Abdollahi, M, Ghobadian, B, Najafi, G, Hoseini, SS, Mofijur, M & Mazlan, M 2020, 'Impact of water – biodiesel – diesel nano-emulsion fuel on performance parameters and diesel engine emission', Fuel, vol. 280, pp. 118576-118576.
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© 2020 Elsevier Ltd The use of emulsion fuel in the engine has been reported as an effective solution to reduce the harmful emission. This experimental study examined the effects of nano-emulsion biodiesel fuel on engine efficiency, gas emission parameters and combustion parameters of a single-cylinder air-cooled diesel engine. Nano-emulsion fuel made of 5% waste cooking oil biodiesel and 5% distilled water were used to test the performance of the diesel engine. This fuel was produced using ultrasonic waves by stabilizing 5% by volume tween 80 and spans 80 surfactants in HLB8 (Hydrophilic-Lipophilic Balance). Performance parameters and pollutants emission of a diesel engine using nano-emulsion fuel were compared with emulsion fuel. This test was performed on four different engine loads (25%, 50%, 75%, and 100%) at different speeds of 1700, 2000, 2300, and 2600 rpm. Power, torque, cylinder pressure levels, and emissions including soot opacity, carbon monoxide (CO), unburned hydrocarbon (UHC), carbon dioxide (CO2), and nitrogen oxides (NOX) were measured. The test results show that diesel engine power and torque using nano-emulsion fuel improved by about 4.84% and 4.65% compared to emulsion fuel, respectively. The use of nano-emulsion fuel significantly decreased CO (~11%), UHCs (~6%), NOx (~9%) and soot opacity (~10%) emission. However, a small rise in CO2 (~7%) emission was observed. The combustion result shows that nano-emulsion fuel creates more cylinder pressure (CP) than emulsion fuel during combustion. The highest CP was recorded at 10° crank angle after the top dead centre with diesel fuel. Finally, nano-emulsion fuel can be a satisfactory alternative to diesel fuel in a diesel engine without having to change the engine.
Abu Bakar, MS, Ahmed, A, Jeffery, DM, Hidayat, S, Sukri, RS, Mahlia, TMI, Jamil, F, Khurrum, MS, Inayat, A, Moogi, S & Park, Y-K 2020, 'Pyrolysis of solid waste residues from Lemon Myrtle essential oils extraction for bio-oil production', Bioresource Technology, vol. 318, pp. 123913-123913.
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Solid waste residues from the extraction of essential oils are projected to increase and need to be treated appropriately. Valorization of waste via pyrolysis can generate value-added products, such as chemicals and energy. The characterization of lemon myrtle residues (LMR) highlights their suitability for pyrolysis, with high volatile matter and low ash content. Thermogravimetric analysis/derivative thermogravimetric revealed the maximum pyrolytic degradation of LMR at 335 °C. The pyrolysis of LMR for bio-oil production was conducted in a fixed-bed reactor within a temperature range of 350-550 °C. Gas chromatography-mass spectrometry showed that the bio-oil contained abundant amounts of acetic acid, phenol, 3-methyl-1,2-cyclopentanedione, 1,2-benzenediol, guaiacol, 2-furanmethanol, and methyl dodecanoate. An increase in pyrolysis temperature led to a decrease in organic acid and ketones from 18.09% to 8.95% and 11.99% to 8.75%, respectively. In contrast, guaiacols and anhydrosugars increased from 24.23% to 30.05% and from 3.57% to 7.98%, respectively.
Aghayarzadeh, M, Khabbaz, H, Fatahi, B & Terzaghi, S 2020, 'Interpretation of Dynamic Pile Load Testing for Open-Ended Tubular Piles Using Finite-Element Method', International Journal of Geomechanics, vol. 20, no. 2, pp. 04019169-04019169.
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© 2019 American Society of Civil Engineers. For a foundation to perform safely, the ultimate strength of each pile must satisfy the structural and geotechnical requirements. Pile load testing is considered to be a direct method for determining the ultimate geotechnical capacity of piles. In this paper the dynamic and static response of a driven steel pipe pile monitored as part of a highway bridge construction project in New South Wales, Australia, has been simulated and then numerically analyzed using the finite-element method. A continuum numerical model has been established to simulate the dynamic load testing of steel pipe piles with unplugged behavior in which adopting measured soil properties resulted in a reasonable match between the measured and predicted results and without needing random signal matching in an iterative process. Settlement at the head and toe of the pile was then calculated when a static load represented by a dead load plus a heavy platform load of a bridge was applied over the pile head. During the dynamic and static load testing simulation, a hardening soil model with small strain stiffness was used to obtain the best correlation between the large and small strains, which occurred while the pile was under static load and being driven. The numerical predictions obtained using continuum finite-element simulations were then compared with the corresponding predictions obtained from the Case Western Reserve University (CASE) method and CASE Pile Wave Analysis Program (CAPWAP) to evaluate the predictions. The results show that the hardening soil model with small strain stiffness exhibits a reasonable correlation with the field measurements during static and dynamic loading. Moreover, parametric studies have been carried out in the established continuum numerical model to evaluate how the interface properties between the pile and soil and the reference shear strain define the backbone on the velocity at the head of the pile and trac...
Ahmad, HA, Ni, S-Q, Ahmad, S, Zhang, J, Ali, M, Ngo, HH, Guo, W, Tan, Z & Wang, Q 2020, 'Gel immobilization: A strategy to improve the performance of anaerobic ammonium oxidation (anammox) bacteria for nitrogen-rich wastewater treatment', Bioresource Technology, vol. 313, pp. 123642-123642.
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Anaerobic ammonium oxidation (anammox) process appears a suitable substitute to nitrification-denitrification at a lower C/N ratios. Anammox is a chemolithoautotrophic process, belong to phylum Planctomycetes, and they are slow growing bacteria. Different strategies, e.g., biofilm formation, granulation and gel immobilization, have been applied to maintain a critical mass of bacterial cells in the system by avoiding washout from the bioreactor. Gel immobilization of anammox appears the best alternative to the natural process of biofilm formation and granulation. Polyvinyl alcohol-sodium alginate, polyethylene glycol, and waterborne polyurethane are the most reported materials used for the entrapment of anammox bacteria. However, dissolution of the gel beads refrains its application for long term bioprocess. Magnetic powder could coat on the surface of the beads which may increase the mechanical strength and durability of pellets. Application and problem of immobilization technology for the commercialization of this technology also addressed.
Ahmed, MB, Alam, MM, Zhou, JL, Xu, B, Johir, MAH, Karmakar, AK, Rahman, MS, Hossen, J, Hasan, ATMK & Moni, MA 2020, 'Advanced treatment technologies efficacies and mechanism of per- and poly-fluoroalkyl substances removal from water', Process Safety and Environmental Protection, vol. 136, pp. 1-14.
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© 2020 Institution of Chemical Engineers The increasing occurrence of chemically resistant per- and poly-fluoroalkyl substances (PFASs) in the natural environment, animal tissues and even the human body poses a significant health risk. Temporal trend studies on water, sediments, bird, fish, marine mammal and the human show that the exposure of PFAS has significantly increased over the last 20–30 years. Different physical, biological and chemical treatment processes have been investigated for PFAS removal from water. However, there is a lack of detailed understating of the mechanism of removal by different methods, especially by different advanced chemical treatment processes. This article reviews PFASs removal efficacy and mechanism by the advanced chemical treatment methods from aqueous solution. Review shows that several advanced oxidation processes (e.g., electrochemical oxidation, activated persulfate oxidation, photocatalysis, UV-induced oxidation) are successful in degrading PFASs. Moreover, defluorination treatment, some thermal and non-thermal degradation processes are also found to be prominent for the degradation of PFASs with some limitations including process costs over physical treatment (e.g., sorption), production of toxic by-products and greenhouse gases. Finally, knowledge gaps concerning the advanced chemical treatment of PFASs are discussed.
Ahmed, MB, Johir, MAH, McLaughlan, R, Nguyen, LN, Xu, B & Nghiem, LD 2020, 'Per- and polyfluoroalkyl substances in soil and sediments: Occurrence, fate, remediation and future outlook', Science of The Total Environment, vol. 748, pp. 141251-141251.
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Ajani, PA, Lim, HC, Verma, A, Lassudrie, M, McBean, K, Doblin, MA & Murray, SA 2020, 'First report of the potentially toxic marine diatom Pseudo‐nitzschia simulans (Bacillariophyceae) from the East Australian Current', Phycological Research, vol. 68, no. 3, pp. 254-259.
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SUMMARYCertain species of the marine diatom genus Pseudo‐nitzschia are responsible for the production of the domoic acid (DA), a neurotoxin that can bioaccumulate in the food chain and cause amnesic shellfish poisoning (ASP) in animals and humans. This study extends our knowledge by reporting on the first observation of the potentially toxic species Pseudo‐nitzschia simulans from this region. One clonal strain of P. simulans was isolated from the East Australian Current and characterized using light and transmission electron microscopy, and phylogenetic analyses based on regions of the internal transcribed spacer (ITS) and the D1–D3 region of the large subunit (LSU) of the nuclear‐encoded ribosomal deoxyribonucleic acid (rDNA), as well as examined for DA production as measured by liquid chromatography–mass spectrometry. Although this strain was non‐toxic under the defined growth conditions, the results unambiguously confirmed that this isolate is the potentially toxic species P. simulans – the first report of this species from the Southern Hemisphere.
Akther, N, Ali, SM, Phuntsho, S & Shon, H 2020, 'Surface modification of thin-film composite forward osmosis membranes with polyvinyl alcohol–graphene oxide composite hydrogels for antifouling properties', Desalination, vol. 491, pp. 114591-114591.
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© 2020 Elsevier B.V. In this study, the polyamide (PA) layers of commercial thin-film composite (TFC) forward osmosis (FO) membranes were coated with glutaraldehyde cross-linked polyvinyl alcohol (PVA) hydrogel comprising of graphene oxide (GO) at various loadings to enhance their fouling resistance. The optimal GO concentration of 0.02 wt% in hydrogel solution was confirmed from the FO membrane performance, and its influence on membrane antifouling properties was studied. The properties of the modified membranes, such as surface morphology, surface charge and wettability, were also investigated. PVA/GO coating was observed to increase the smoothness and hydrophilicity of the membrane surface. The foulant resistances of the pristine, PVA-coated and PVA/GO-coated membranes were also reported. PVA hydrogel-coated TFC membrane with a GO loading of 0.02 wt% showed a 55% reduction in specific reverse solute flux, only a marginal reduction in the water flux, and the best antifouling property with a 58% higher flux recovery than the pristine TFC membrane. The significant improvement in the selectivity of the modified membranes meant that the hydrogel coating could be used to seal PA defects. The biocidal GO flakes in PVA hydrogel coating also improved the biofouling resistance of the modified membranes, which could be attributed to their morphologies and superior surface properties.
Akther, N, Yuan, Z, Chen, Y, Lim, S, Phuntsho, S, Ghaffour, N, Matsuyama, H & Shon, H 2020, 'Influence of graphene oxide lateral size on the properties and performances of forward osmosis membrane', Desalination, vol. 484, pp. 114421-114421.
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Alam, MM, Hossain, MA, Hossain, MD, Johir, MAH, Hossen, J, Rahman, MS, Zhou, JL, Hasan, ATMK, Karmakar, AK & Ahmed, MB 2020, 'The Potentiality of Rice Husk-Derived Activated Carbon: From Synthesis to Application', Processes, vol. 8, no. 2, pp. 203-203.
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Activated carbon (AC) has been extensively utilized as an adsorbent over the past few decades. AC has widespread applications, including the removal of different contaminants from water and wastewater, and it is also being used in capacitors, battery electrodes, catalytic supports, and gas storage materials because of its specific characteristics e.g., high surface area with electrical properties. The production of AC from naturally occurring precursors (e.g., coal, biomass, coconut shell, sugarcane bagasse, and so on) is highly interesting in terms of the material applications in chemistry; however, recently much focus has been placed on the use of agricultural wastes (e.g., rice husk) to produce AC. Rice husk (RH) is an abundant as well as cheap material which can be converted into AC for various applications. Various pollutants such as textile dyes, organic contaminants, inorganic anions, pesticides, and heavy metals can be effectively removed by RH-derived AC. In addition, RH-derived AC has been applied in supercapacitors, electrodes for Li-ion batteries, catalytic support, and energy storage, among other uses. Cost-effective synthesis of AC can be an alternative for AC production. Therefore, this review mainly covers different synthetic routes and applications of AC produced from RH precursors. Different environmental, catalytic, and energy applications have been pinpointed. Furthermore, AC regeneration, desorption, and relevant environmental concerns have also been covered. Future scopes for further research and development activities are also discussed. Overall, it was found that RH-derived AC has great potential for different applications which can be further explored at real scales, i.e., for industrial applications in the future.
Alhathal Alanezi, A, Alqahs Alanezi, Y, Alazmi, R, Altaee, A, Alsalhy, QF & Sharif, AO 2020, 'Enhancing performance of the membrane distillation process using air injection zigzag system for water desalination', DESALINATION AND WATER TREATMENT, vol. 207, pp. 43-50.
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A novel design of an air injection zigzag system was developed to enhance the tubular membrane distillation module’s performance for desalination of water, unlike the basic design that works without an air injection system. Designed in a zigzag mode, the membrane distillation module is set to yield a high turbulence flow. Operating parameter effects, e.g. the feed temperature (40, 50, 60, and 70°C), feed concentration (1, 3, and 5 g/L), and airflow rate (30 - 90 L/h), on process performance were investigated. The system proved its capability to enhance the heat and mass transfer coefficients. The basic and developed modules’ performances were compared in terms of permeate flux (Jm) and thermal efficiency (η). The Reynolds Number increased threefold, which consequently, increased the mass transfer coefficient by 25% and the heat transfer coefficient twofold compared to the basic module at air flow rate of 90 (L/h). Moreover, the thermal efficiency and permeate flux were higher than the basic module’s by roughly 1.4 and 1.5-fold, respectively, for a 5 g/L feed concentration.
Ali, SM, Qamar, A, Phuntsho, S, Ghaffour, N, Vrouwenvelder, JS & Shon, HK 2020, 'Conceptual design of a dynamic turbospacer for efficient low pressure membrane filtration', Desalination, vol. 496, pp. 114712-114712.
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ALIBEIKLOO, M, ISFAHANI, HS & KHABBAZ, H 2020, 'EFFECT OF SURCHARGE HEIGHT AND PRELOADING TIME ON LONG-TERM SETTLEMENT OF CLOSED LANDFILLS: A NUMERICAL ANALYSIS', WIT Transactions on Ecology and the Environment, vol. 247, pp. 81-92.
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In recent years, by developing cities and increasing population, reconstructing on closed landfill sites is unavoidable in some regions. Long-term settlement is one of the major concerns associated with reconstruction on landfills after closure. The purpose of this research is evaluating the effect of preloading in various patterns of height and time on long-term settlements of closed landfills. In this regard, five scenarios of surcharge from 1 to 3 m high within 3, 4.5 and 6 months of preloading time have been modelled using PLAXIS 2D software. Moreover, the numerical results have been compared to those obtained from analytical methods, and a good agreement has been achieved. The findings indicate that there is a linear relationship between settlement and surcharge height. Although, long-term settlement decreased by applying a longer and higher preloading, the time of preloading was found to be a more effective factor compared to preloading height.
Al-Jubainawi, A, Ma, Z, Guo, Y & Nghiem, LD 2020, 'Effect of regulating main governing factors on the selectivity membranes of electrodialysis used for LiCl liquid desiccant regeneration', Journal of Building Engineering, vol. 28, pp. 101022-101022.
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Allison‐Logan, S, Fu, Q, Sun, Y, Liu, M, Xie, J, Tang, J & Qiao, GG 2020, 'From UV to NIR: A Full‐Spectrum Metal‐Free Photocatalyst for Efficient Polymer Synthesis in Aqueous Conditions', Angewandte Chemie, vol. 132, no. 48, pp. 21576-21580.
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AbstractPhoto‐mediation offers unparalleled spatiotemporal control over controlled radical polymerizations (CRP). Photo‐induced electron/energy transfer reversible addition–fragmentation chain transfer (PET‐RAFT) polymerization is particularly versatile owing to its oxygen tolerance and wide range of compatible photocatalysts. In recent years, broadband‐ and near‐infrared (NIR)‐mediated polymerizations have been of particular interest owing to their potential for solar‐driven chemistry and biomedical applications. In this work, we present the first example of a novel photocatalyst for both full broadband‐ and NIR‐mediated CRP in aqueous conditions. Well‐defined polymers were synthesized in water under blue, green, red, and NIR light irradiation. Exploiting the oxygen tolerant and aqueous nature of our system, we also report PET‐RAFT polymerization at the microliter scale in a mammalian cell culture medium.
Allison‐Logan, S, Fu, Q, Sun, Y, Liu, M, Xie, J, Tang, J & Qiao, GG 2020, 'From UV to NIR: A Full‐Spectrum Metal‐Free Photocatalyst for Efficient Polymer Synthesis in Aqueous Conditions', Angewandte Chemie International Edition, vol. 59, no. 48, pp. 21392-21396.
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AbstractPhoto‐mediation offers unparalleled spatiotemporal control over controlled radical polymerizations (CRP). Photo‐induced electron/energy transfer reversible addition–fragmentation chain transfer (PET‐RAFT) polymerization is particularly versatile owing to its oxygen tolerance and wide range of compatible photocatalysts. In recent years, broadband‐ and near‐infrared (NIR)‐mediated polymerizations have been of particular interest owing to their potential for solar‐driven chemistry and biomedical applications. In this work, we present the first example of a novel photocatalyst for both full broadband‐ and NIR‐mediated CRP in aqueous conditions. Well‐defined polymers were synthesized in water under blue, green, red, and NIR light irradiation. Exploiting the oxygen tolerant and aqueous nature of our system, we also report PET‐RAFT polymerization at the microliter scale in a mammalian cell culture medium.
Alosime, EM, Alshahrani, AA, Nghiem, LD & in het Panhuis, M 2020, 'The preparation and characterization of buckypaper made from carbon nanotubes impregnated with chitosan', Polymer Composites, vol. 41, no. 4, pp. 1393-1404.
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AbstractBiopolymer chitosan was incorporated into a thin multiwalled carbon nanotube membrane (MWNT buckypaper) via filtration and soaking in 0.1% (w/v) of low‐molecular‐weight (MW) chitosan. The properties of the buckypaper membrane before and after annealing and after soaking were characterized by measurement of their electrical conductivities (19 ± 2 to 42 ± 2 S/cm), contact angles (31 ± 4° to 71 ± 4°), and mechanical properties (tensile strength, small‐ranging between 1.4 ± 0.1 and 4.2 ± 0.7 MPa; Young's modulus: 85 ± 4 to 443 ± 20 MPa). Moreover, the morphological properties, surface area, and permeability toward water of these buckypaper membranes were characterized and compared with corresponding carbon nanotube membranes prepared with Triton X‐100 (Trix) as the surfactant. Scanning electron microscopic (SEM) images and Brunauer, Emmett, and Teller (BET) data of MWNT‐annealing buckypaper membranes revealed that the diameters of their surface pores were significantly higher than that of the corresponding buckypaper membranes soaked in chitosan solution. The solution of chitosan incorporated inside the porous structure of the annealed MWNT membrane led to a significantly reduced surface area and pore size distribution of the composite membrane, revealing that this could be a useful method for desalination.
Alshahrani, AA, Alsohaimi, IH, Alshehri, S, Alawady, AR, El-Aassar, MR, Nghiem, LD & Panhuis, MIH 2020, 'Nanofiltration membranes prepared from pristine and functionalised multiwall carbon nanotubes/biopolymer composites for water treatment applications', Journal of Materials Research and Technology, vol. 9, no. 4, pp. 9080-9092.
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Al-Shetwi, AQ, Hannan, MA, Jern, KP, Mansur, M & Mahlia, TMI 2020, 'Grid-connected renewable energy sources: Review of the recent integration requirements and control methods', Journal of Cleaner Production, vol. 253, pp. 119831-119831.
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© 2020 Elsevier Ltd The growing of renewable power generation and integration into the utility grid has started to touch on the security and stability of the power system operation. Hence, the grid integration requirements have become the major concern as renewable energy sources (RESs) such as wind and solar photovoltaic (PV) started to replace the conventional power plant slowly. In line with this, some of the new requirements and technical regulations have been established to ensure grid stability. This study aims to fill the gap and conduct an updating review of the recent integration requirements and compliance control methods regarding the penetration of renewable power plants to the power grid. The review is conducted by a comparing of the key requirements related to voltage stability, frequency stability, voltage ride-through (VRT), power quality, active and reactive power regulations towards grid stability. In order to fulfill these requirements, different control methods have been recently proposed. Accordingly, this paper compares and reviews the state-of-the-art solutions for compliance technology and control methods. Furthermore, a broad discussion on the global harmonization of the integration requirements, challenges, advantages and disadvantages is also highlighted. The rigorous review indicates that although the recent integration requirements can improve the grid operation, stability, security, and reliability, further improvements are still required with respect to protective regulations, global harmonization, and control optimization. Various recommendations for future research related to the integration and technical regulations of RESs are then presented. In sum, the insights provided by this review may aid the development of smooth and stable grid integration of RESs, help developers and researchers to develop the design and control strategies in the sense of current requirements. Additionally, assist power system operators in est...
Altaee, A & AlZainati, N 2020, 'Novel Thermal Desalination Brine Reject-Sewage Effluent Salinity Gradient for Power Generation and Dilution of Brine Reject', Energies, vol. 13, no. 7, pp. 1756-1756.
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Salinity gradient resource presents an essential role for power generated in the process of pressure-retarded osmosis (PRO). Researchers proposed several designs for coupling the PRO process with the desalination plants, particularly reverse osmosis technology for low-cost desalination but there is no study available yet on the utilization of the concentrated brine reject from a thermal desalination plant. This study evaluates the feasibility of power generation in the PRO process using thermal plant brine reject-tertiary sewage effluent (TSE) salinity gradient resource. Power generation in the PRO process was determined for several commercially available FO membranes. Water flux in Oasys Forward Osmosis membrane was more than 31 L/m2h while the average water flux in the Oasys module was 17 L/m2h. The specific power generation was higher in the thin film composite (TFC) membranes compared to the cellulose triacetate (CTA) membranes. The specific power generation for the Oasys membrane was 0.194 kWh/m3, which is 41% of the maximum Gibbs energy of the brine reject-TSE salinity gradient. However, the Hydration Technology Innovation CTA membrane extracted only 0.133 kWh/m3 or 28% of Gibbs free energy of mixing for brine reject-TSE salinity gradient. The study reveals the potential of the brine reject-TSE salinity gradient resource for power generation and the dilution of brine reject.
Altaee, A, Khlaifat, N & Zhou, JL 2020, 'Assessment of wind energy potential at Yanco, New South Wales, Australia', International Journal of Industrial Electronics and Electrical Engineering, vol. 8, no. 1, pp. 26-30.
Arjmandi, A, Peyravi, M, Arjmandi, M & Altaee, A 2020, 'Exploring the use of cheap natural raw materials to reduce the internal concentration polarization in thin-film composite forward osmosis membranes', Chemical Engineering Journal, vol. 398, pp. 125483-125483.
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© 2020 Elsevier B.V. Internal concentration polarization (ICP) is a significant problem in Forward osmosis (FO) membranes, which reduces the water flux. In order to mitigate the ICP phenomenon, rice bran (RB) and wood sawdust (WSD) particles were selected as natural green pore formers and incorporated into the polyethersulfone (PES) matrix to fabricate mixed matrix membranes (MMMs). Fabricated MMMs were used as the porous support layer (SL) to make thin-film composite (TFC) FO membranes. Firstly, the water uptake experiment was performed to evaluate the water adsorption capacity of the RB and WSD particles. Furthermore, all samples were characterized by FTIR, FESEM, AFM, XPS, DLS, static contact angle (CA), and tensile strength. Also, performance tests in reverse osmosis (RO) and the FO units were performed to evaluate the fabricated membranes. The results showed that the use of RB and WSD particles dramatically reduced the structural parameter in all MMMs, resulting in lower ICP effects and high water flux. Due to the softer structure, smaller size, and more water uptake, the RB-based TFC membranes recorded better results. The TFC-RB-5 (with 5% of RB in the SL) was the best membrane with a water flux of about 65.71 L/m2.h for Caspian seawater desalination, while the FO water flux for DI water as the feed solution (FS) was 83.65 L/m2.h. The present study showed the membranes made in this study are competitive with the existing FO membranes and very cost-effective for broad applications.
Arjmandi, M, Altaee, A, Arjmandi, A, Pourafshari Chenar, M, Peyravi, M & Jahanshahi, M 2020, 'A facile and efficient approach to increase the magnetic property of MOF-5', Solid State Sciences, vol. 106, pp. 106292-106292.
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© 2020 Elsevier Masson SAS In this study, a facile and efficient approach to increase the magnetic property of metal-organic framework-5 (MOF-5) has been investigated. The basis of this approach is the encapsulation of cluster-oxygen composition (i.e. ZnO in MOF-5) during the synthesis process of MOF-5 to form ZnO@MOF-5 nanocrystals. Both MOF-5 and ZnO@MOF-5 were synthesized for comparison purposes, considering their magnetic property. The physicochemical properties of MOF-5 and ZnO@MOF-5 were characterized by XRD, FTIR, TGA, DLS, FESEM, and Magnetization measurements. The FTIR spectra confirmed the presence of additional ZnO molecules in the ZnO@MOF-5 structure. Results from the XRD showed that the presence of additional ZnO molecules in the ZnO@MOF-5 altered the structure of MOF-5. The TGA analysis also confirmed the presence of additional ZnO molecules in the ZnO@MOF-5 structure, indicating that the ZnO@MOF-5 contains 15.23 wt% ZnO more than MOF-5. The FESEM and DLS results showed that the average sizes of MOF-5 and ZnO@MOF-5 nanocrystals are below 100 nm, with no defined morphology. Finally, the magnetization measurements showed that the MOF-5 nanocrystals have diamagnetic properties. For ZnO@MOF-5 nanocrystals, a ferromagnetic-like character was observed in the scanned field range and the saturation value of about 2.59 × 10−3 emu/g was obtained. The success of this facile and hassle-free approach can be an important step towards enhancing the magnetic properties of MOFs.
Arjmandi, M, Peyravi, M, Altaee, A, Arjmandi, A, Pourafshari Chenar, M, Jahanshahi, M & Binaeian, E 2020, 'A state-of-the-art protocol to minimize the internal concentration polarization in forward osmosis membranes', Desalination, vol. 480, pp. 114355-114355.
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© 2020 Elsevier B.V. The main reason for the lower water flux, than expected, in the forward osmosis (FO) process, is the internal concentration polarization (DICP). Usually, the structural parameter (S) is used as an indicator of the intensity of DICP. Small S value is desirable for the FO membrane due to the low DICP. However, due to design and construction problems, structural parameter reduction has some drawbacks. In this work, DICP reduction in FO membranes will be investigated using an approach other than structural parameter reduction. Accordingly, during the FO process, the feed solution (FS) valve is opened and closed at a constant period of time (feed valve timing (FVT)). Four types of FO membranes with different S parameters were used. The effects of the implementation of the proposed protocol on the water flux (Jw), reverse salt flux (Js), specific reverse solute flux (Js/Jw) and effective driving force were investigated. The effects of the S parameter and draw solution (DS) concentration also investigated separately. The results showed that the proposed protocol significantly increased Jw. Also, the values of Js/Jw decreased with increasing the FVT values and reached the lowest level in the practical recovery time (PRT).
Arjmandi, M, Pourafshari Chenar, M, Altaee, A, Arjmandi, A, Peyravi, M, Jahanshahi, M & Binaeian, E 2020, 'Caspian seawater desalination and whey concentration through forward osmosis (FO)-reverse osmosis (RO) and FO-FO-RO hybrid systems: Experimental and theoretical study', Journal of Water Process Engineering, vol. 37, pp. 101492-101492.
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Bai, X, Sun, B, Wang, X, Zhang, T, Hao, Q, Ni, B-J, Zong, R, Zhang, Z, Zhang, X & Li, H 2020, 'Defective crystal plane-oriented induced lattice polarization for the photocatalytic enhancement of ZnO', CrystEngComm, vol. 22, no. 16, pp. 2709-2717.
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The mechanism of the photocatalytic reaction of defective ZnO systems was determined.
Bai, X, Wang, X, Lu, X, Liang, Y, Li, J, Wu, L, Li, H, Hao, Q, Ni, B-J & Wang, C 2020, 'Surface defective g-C3N4−Cl with unique spongy structure by polarization effect for enhanced photocatalytic removal of organic pollutants', Journal of Hazardous Materials, vol. 398, pp. 122897-122897.
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Natural sponge is an ancient marine organism with a single lamellar structure, on which there are abundant porous channels to compose full-fledged spatial veins. Illumined by the natural spongy system, herein, the Cl doped surface defective graphite carbon nitride (g-C3N4-xClx) was constructed through microwave etching. In this process, microwave with HCl was employed to produce surface defects and peel bulk g-C3N4 to form natural spongy structured g-C3N4-xClx with three-dimensional networks. The spongy structure of the photocatalyst could provide abundant and unobstructed pathways for the transfer and separation of electron-hole pairs, and it was beneficial for photocatalytic reaction. The spongy defective g-C3N4-xClx achieved excellent degradation of diclofenac sodium (100%), bisphenol A (88.2%), phenol (85.7%) and methylene blue (97%) solution under simulated solar irradiation, respectively. The chlorine atoms were introduced into the g-C3N4 skeleton in microwave field with HCl, forming C-Cl bonds and surface polarization field, which could significantly accelerate the separation of photogenerated electrons and holes. As an efficient and universal approach, microwave etching can be generally used to create surface defects for most photocatalysts, which may have potential applications in environmental purification, energy conversion and photodynamic therapy.
Baird, ME, Wild-Allen, KA, Parslow, J, Mongin, M, Robson, B, Skerratt, J, Rizwi, F, Soja-Woźniak, M, Jones, E, Herzfeld, M, Margvelashvili, N, Andrewartha, J, Langlais, C, Adams, MP, Cherukuru, N, Gustafsson, M, Hadley, S, Ralph, PJ, Rosebrock, U, Schroeder, T, Laiolo, L, Harrison, D & Steven, ADL 2020, 'CSIRO Environmental Modelling Suite (EMS): scientific description of the optical and biogeochemical models (vB3p0)', Geoscientific Model Development, vol. 13, no. 9, pp. 4503-4553.
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Abstract. Since the mid-1990s, Australia's Commonwealth Science Industry and Research Organisation (CSIRO) has been developing a biogeochemical (BGC) model for coupling with a hydrodynamic and sediment model for application in estuaries, coastal waters and shelf seas. The suite of coupled models is referred to as the CSIRO Environmental Modelling Suite (EMS) and has been applied at tens of locations around the Australian continent. At a mature point in the BGC model's development, this paper presents a full mathematical description, as well as links to the freely available code and user guide. The mathematical description is structured into processes so that the details of new parameterisations can be easily identified, along with their derivation. In EMS, the underwater light field is simulated by a spectrally resolved optical model that calculates vertical light attenuation from the scattering and absorption of 20+ optically active constituents. The BGC model itself cycles carbon, nitrogen, phosphorous and oxygen through multiple phytoplankton, zooplankton, detritus and dissolved organic and inorganic forms in multiple water column and sediment layers. The water column is dynamically coupled to the sediment to resolve deposition, resuspension and benthic–pelagic biogeochemical fluxes. With a focus on shallow waters, the model also includes detailed representations of benthic plants such as seagrass, macroalgae and coral polyps. A second focus has been on, where possible, the use of geometric derivations of physical limits to constrain ecological rates. This geometric approach generally requires population-based rates to be derived from initially considering the size and shape of individuals. For example, zooplankton grazing considers encounter rates of one predator on a prey field based on summing relative motion of the predator with the prey individuals and the search area; chlorophyll synthesis includes a geometrically derived self-shading t...
Bao, T, Damtie, MM, Hosseinzadeh, A, Wei, W, Jin, J, Phong Vo, HN, Ye, JS, Liu, Y, Wang, XF, Yu, ZM, Chen, ZJ, Wu, K, Frost, RL & Ni, B-J 2020, 'Bentonite-supported nano zero-valent iron composite as a green catalyst for bisphenol A degradation: Preparation, performance, and mechanism of action', Journal of Environmental Management, vol. 260, pp. 110105-110105.
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Bisphenol A (BPA) is a toxic environmental pollutant commonly found in wastewater. Using non-toxic materials and eco-friendly technology to remove this pollutant from wastewater presents multiple advantages. Treatment of wastewater with clay minerals has received growing interest because of the environment friendliness of these materials. Bentonite is a 2:1 layered phyllosilicate clay mineral that can support nano-metal catalysts. It can prevent the agglomeration of nano-metal catalysts and improve their activity. In this article, a green catalytic nano zero-valent iron/bentonite composite material (NZVI@bentonite) was synthesized via liquid-phase reduction. The average size of NZVI was approximately 40-50 nm. Good dispersion and low aggregation were observed when NZVI was loaded on the surface or embedded into the nanosheets of bentonite. Degradation of BPA, a harmful contaminant widely found in wastewater at relatively high levels, by NZVI@bentonite was then investigated and compared with that by pristine NZVI through batch Fenton-like reaction experiments. Compared with pristine NZVI and bentonite alone, the NZVI@bentonite showed a higher BPA degradation ratio and offered highly effective BPA degradation up to 450 mg/g in wastewater under optimum operating conditions. Adsorption coupled with the Fenton-like reaction was responsible for BPA degradation by NZVI@bentonite. This work extends the application of NZVI@bentonite as an effective green catalyst for BPA degradation in aqueous environments.
Barolo, L, Abbriano, RM, Commault, AS, George, J, Kahlke, T, Fabris, M, Padula, MP, Lopez, A, Ralph, PJ & Pernice, M 2020, 'Perspectives for Glyco-Engineering of Recombinant Biopharmaceuticals from Microalgae', Cells, vol. 9, no. 3, pp. 633-633.
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Microalgae exhibit great potential for recombinant therapeutic protein production, due to lower production costs, immunity to human pathogens, and advanced genetic toolkits. However, a fundamental aspect to consider for recombinant biopharmaceutical production is the presence of correct post-translational modifications. Multiple recent studies focusing on glycosylation in microalgae have revealed unique species-specific patterns absent in humans. Glycosylation is particularly important for protein function and is directly responsible for recombinant biopharmaceutical immunogenicity. Therefore, it is necessary to fully characterise this key feature in microalgae before these organisms can be established as industrially relevant microbial biofactories. Here, we review the work done to date on production of recombinant biopharmaceuticals in microalgae, experimental and computational evidence for N- and O-glycosylation in diverse microalgal groups, established approaches for glyco-engineering, and perspectives for their application in microalgal systems. The insights from this review may be applied to future glyco-engineering attempts to humanize recombinant therapeutic proteins and to potentially obtain cheaper, fully functional biopharmaceuticals from microalgae.
Bates, H, Zavafer, A, Szabó, M & Ralph, PJ 2020, 'The Phenobottle, an open-source photobioreactor platform for environmental simulation', Algal Research, vol. 52, pp. 102105-102105.
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© 2020 Elsevier B.V. Microalgal biotechnologies have great potential for biofuels, bioremediation, food technologies and more recently the production of pharmaceuticals. However, a major obstacle to use microalgae industrially is the optimisation of environmental parameters to the microalgal species of interest (light, CO2 availability, nutrients, etc.). If one aims to optimise productivity, the use of photobioreactors (PBRs) is essential. However, the restrictive design of the few commercial bioreactors and their elevated costs (> $10,000 USD ea.) prevents their use as a mainstream tool. To propel microalgal research we present the Phenobottle, a fully customizable open-source PBR platform (consisting of hardware and software). As the optimisation of photosynthesis is a central process to increasing the productivity of microalgae, the Phenobottle is equipped with a chlorophyll a fluorometer and growth sensors to probe metabolic performance in near-real time. An introductory guide is provided and the Phenobottle's sensors are benchmarked against commercial instruments using the model green alga Chlorella vulgaris.
Bhuiya, MMK, Rasul, M, Khan, M, Ashwath, N & Mofijur, M 2020, 'Comparison of oil extraction between screw press and solvent (n-hexane) extraction technique from beauty leaf (Calophyllum inophyllum L.) feedstock', Industrial Crops and Products, vol. 144, pp. 112024-112024.
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© 2019 Elsevier B.V. An experimental investigation was conducted to evaluate the effects of the processing of the raw materials, such as preparation and extraction, grating (whole and grated), drying and moisture conditioning of the seed kernels on the yield of oil extraction. Both mechanical and chemical methods were used to extract oil from the beauty leaf (BL) seed kernel using a screw press expeller and n-hexane as an oil solvent, respectively. Both whole kernel (WK) and grated kernel (GK) were used in screw press technique, whereas, only GK was used in n-hexane technique. The study indicated that the kernels prepared for 14.4 % moisture content (MC) produced the highest yield of oil in both methods. The highest oil yield of 86.4 % was obtained on the basis of the weight of the kernel in n-hexane method for the GK. On the other hand, the oil yield of 78.0 and 72.1 % was achieved using a screw press technique for the GK and WK, respectively. The gas chromatography (GC) analysis was conducted to determine the fatty acid compositions of beauty leaf oil. The physico-chemical properties of the beauty leaf oil (BLO) were evaluated. A comparison of fossil energy ratio (FER) was made between n-hexane and screw press methods. The FER in-hexane method was found 4.9, whereas, in screw press method it was found 3.4 and 3.1 for the GK and WK, respectively, which indicates that n-hexane method is more efficient than screw press technique. This study provides an understanding of the basis of selecting an appropriate oil extraction technique for oil extraction users in large scale applications.
Bian, Y, Wang, D, Liu, X, Yang, Q, Liu, Y, Wang, Q, Ni, B-J, Li, H & Zhang, Y 2020, 'The fate and impact of TCC in nitrifying cultures', Water Research, vol. 178, pp. 115851-115851.
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Triclocarban (TCC) is a highly effective antibacterial agent, which is widely used in a variety of applications and present at significant levels (e.g., 760 μg/L) in wastewater worldwide. However, the interaction between TCC and nitrifiers, important microbial cultures in wastewater treatment plants, has not been documented. This work therefore aimed to evaluate the fate of TCC in a nitrifying culture and its impact on nitrifiers in four long-term nitrifiers-rich reactors, which received synthetic wastewater containing 0, 0.1, 1, or 5 mg/L TCC. Experimental results showed that 36.7%-50.7% of wastewater TCC was removed by nitrifying cultures in stable operation. Mass balance analysis revealed that the removal of TCC was mainly achieved through adsorption rather than biodegradation. Adsorption kinetic analysis indicated that inhomogeneous multilayer adsorption was responsible for the removal while fourier transform infrared spectroscopy indicated that several functional groups such as hydroxyl, amide and polysaccharide seemed to be the main adsorption sites. The adsorbed TCC significantly deteriorated settleability and performance of nitrifying cultures. With an increase of influent TCC from 0 to 5 mg/L, reactor volatile suspended solids and effluent nitrate decreased from 1200 ± 90 mg/L and 300.81 ± 7.52 mg/L to 880 ± 80 and 7.35 ± 4.62 mg/L while effluent ammonium and nitrite increased from 0.41 ± 0.03 and 0.45 ± 0.23 mg/L to104.65 ± 3.46 and 182.06 ± 7.54 mg/L, respectively. TCC increased the extracellular polymeric substances of nitrifying cultures, inhibited the specific activities of nitrifiers, and altered the abundance of nitrifiers especially Nitrospira sp.. In particular, TCC at environmentally relevant concentration (i.e., 0.1 mg/L) significantly inhibited NOB activity and reduced NOB population.
Chan, NJ-A, Gu, D, Tan, S, Fu, Q, Pattison, TG, O’Connor, AJ & Qiao, GG 2020, 'Spider-silk inspired polymeric networks by harnessing the mechanical potential of β-sheets through network guided assembly', Nature Communications, vol. 11, no. 1.
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AbstractThe high toughness of natural spider-silk is attributed to their unique β-sheet secondary structures. However, the preparation of mechanically strong β-sheet rich materials remains a significant challenge due to challenges involved in processing the polymers/proteins, and managing the assembly of the hydrophobic residues. Inspired by spider-silk, our approach effectively utilizes the superior mechanical toughness and stability afforded by localised β-sheet domains within an amorphous network. Using a grafting-from polymerisation approach within an amorphous hydrophilic network allows for spatially controlled growth of poly(valine) and poly(valine-r-glycine) as β-sheet forming polypeptides via N-carboxyanhydride ring opening polymerisation. The resulting continuous β-sheet nanocrystal network exhibits improved compressive strength and stiffness over the initial network lacking β-sheets of up to 30 MPa (300 times greater than the initial network) and 6 MPa (100 times greater than the initial network) respectively. The network demonstrates improved resistance to strong acid, base and protein denaturants over 28 days.
Chang, Z, Long, G, Zhou, JL & Ma, C 2020, 'Valorization of sewage sludge in the fabrication of construction and building materials: A review', Resources, Conservation and Recycling, vol. 154, pp. 104606-104606.
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© 2019 Elsevier B.V. With increasing amount of sewage sludge becoming an urgent and inevitable issue for every country, its applications in the production of construction and building materials provide an alternative solution for sludge disposal and resource recovery. Similar to clay and Portland cement, the main oxides in sewage sludge are SiO2 (10–25 %), Al2O3 (5–10 %) and CaO (10–30 %) which are increased in sludge ash after incineration to 25–50 %, 10–20 % and 15–30 %. Therefore, this solid waste can be utilized not only as raw material for the production of eco-cement, bricks, ceramic materials and lightweight aggregates through sintering process, but also as supplementary admixtures in cementitious materials such as pozzolanic component, fine aggregate or filling material. By critically reviewing current utilizations of sewage sludge, it is feasible to replace up to 15 % natural raw materials with sewage sludge in cement production and the manufactured eco-cement clinkers show comparable performance to traditional Portland cement. Whilst as raw feed in the fabrication of bricks, ceramic materials and lightweight aggregates, 20 % of sewage sludge substitution is acceptable to produce good quality products (within 8 % firing shrinkage and 15 % water absorption). Though high content of organic matter in raw sludge causes a decrease in mechanical strength and delay in hydration process, controlled low-strength materials offer an innovative reuse with large amount of sludge. The immobilization of heavy metals in products prevents sewage sludge causing secondary environmental pollution. Furthermore, suggestions for future research are proposed in order to strengthen the high value-added applications of sewage sludge.
Chen, X, Rodríguez, Y, López, JC, Muñoz, R, Ni, B-J & Sin, G 2020, 'Modeling of Polyhydroxyalkanoate Synthesis from Biogas by Methylocystis hirsuta', ACS Sustainable Chemistry & Engineering, vol. 8, no. 9, pp. 3906-3912.
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Copyright © 2020 American Chemical Society. Methylocystis hirsuta, a type II methanotroph, has been experimentally demonstrated to be able to efficiently synthesize polyhydroxyalkanoates (PHA) from biogas under nutrient-limited conditions. A mechanistic model capable of describing the relevant processes of M. hirsuta, which is currently not available, would therefore lay a solid foundation for future practical demonstration and optimization of the PHA synthesis technology using biogas. To this end, dedicated batch tests were designed and conducted to obtain experimental data for different mechanistic processes of M. hirsuta. Through utilizing the experimental data of well-designed batch tests and following a step-wise model calibration/validation protocol, the stoichiometrics and kinetics of M. hirsuta are reported for the first time, including the yields of growth and PHA synthesis on CH4 (0.14 ± 0.01 g COD g-1 COD and 0.25 ± 0.02 g COD g-1 COD), the CH4 and O2 affinity constants (5.1 ± 2.1 g COD m-3 and 4.1 ± 1.7 g O2 m-3), the maximum PHA consumption rate (0.019 ± 0.001 g COD g-1 COD d-1), and the maximum PHA synthesis rate on CH4 (0.39 ± 0.05 g COD g-1 COD d-1). Through applying the developed model, an optimal O2:CH4 molar ratio of 1.6 mol O2 mol-1 CH4 was found to maximize the PHA synthesis by M. hirsuta. Practically, the model and parameters obtained would not only benefit the design and operation of bioreactors performing PHA synthesis from biogas, but also enable specific research on selection for type II methanotrophs in diverse environments.
Chen, X, Yang, L, Sun, J, Wei, W, Liu, Y & Ni, B-J 2020, 'Influences of Longitudinal Heterogeneity on Nitrous Oxide Production from Membrane-Aerated Biofilm Reactor: A Modeling Perspective', Environmental Science & Technology, vol. 54, no. 17, pp. 10964-10973.
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As a promising technology for sustainable nitrogen removal from wastewater, the membrane-aerated biofilm reactors (MABRs) performing autotrophic deammonification are faced with the problem of unwanted production of nitrous oxide (N2O, a potent greenhouse gas). As a common tool to study N2O production from such an MABR, the traditional one-dimensional modeling approach fails to simulate the existence of longitudinal gradients in the reactor and therefore might render N2O production significantly deviated from reality. To this end, this work aims to study the influences of key longitudinal gradients (i.e., in oxygen, liquid-phase components, and biofilm thickness) on the N2O production from a typical MABR performing autotrophic deammonification by applying a modified version of a newly developed compartmental model. Through comparing the modeling results of different reactor configurations, this work reveals that the single impact of the longitudinal gradients studied on the N2O production from the MABR follows the order: oxygen (significant) > liquid-phase components (slight) > biofilm thickness (almost none). When multiple longitudinal gradients are present, they become correlated and would jointly influence the N2O production and nitrogen removal of the MABR. The results also show the need for multispot measurements to get an accurate representation of spatial biofilm features of the MABR configuration with the membrane lumen designed/operated as a plug flow reactor. While the traditional modeling approach is acceptable to evaluate the nitrogen removal in most cases, it might overestimate or underestimate the N2O production from the MABR with at least one of the longitudinal gradients in oxygen and liquid-phase components. For such an MABR, the longitudinal heterogeneity in biofilm thickness and the number of biofilm thickness classes to be included in the model would also make a difference to the simulation results, especially the N2O production. The ...
Chen, Z, Duan, X, Wei, W, Wang, S & Ni, B-J 2020, 'Electrocatalysts for acidic oxygen evolution reaction: Achievements and perspectives', Nano Energy, vol. 78, pp. 105392-105392.
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© 2020 Elsevier Ltd Developing efficient electrocatalysts toward acidic oxygen evolution reaction (AOER) is of vital significance in proton exchange membrane (PEM) water electrolysis, which is a promising technique to tackle the approaching energy crisis by supplying high-purity hydrogen. In this work, we first present a general introduction to the AOER mechanism as well as the most important parameters in evaluation of the catalytic performances of catalysts. Fruitful achievements of noble metal-based catalysts (e.g., metals, alloys, and oxides) and noble metal-free catalysts (e.g., transition metal oxides, chalcogenides, and metal-free materials) are fully described, with an emphasis on advanced strategies of catalyst modification/engineering, structure-catalysis correlations, and evolution of catalyst structures and surface chemistry under operational conditions. The representative electrocatalysts are benchmarked based on their catalytic performances. Finally, the challenges are summarized and future opportunities are directed for the rational design of AOER catalysts toward sustainable fuel production.
Chen, Z, Duan, X, Wei, W, Wang, S & Ni, B-J 2020, 'Iridium-based nanomaterials for electrochemical water splitting', Nano Energy, vol. 78, pp. 105270-105270.
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© 2020 Elsevier Ltd Electrochemical water splitting is an appealing technology to produce high-purity hydrogen as a clean and sustainable energy carrier. The efficiency of water splitting largely depends on the intrinsic activity, selectivity, and stability of the electrocatalysts. Hence, soaring scientific endeavors have been made to develop high-performance electrocatalysts and uncover the underling reaction mechanisms. Iridium (Ir)-based nanomaterials are most promising for water splitting due to their favorable intrinsic activity, wide pH window, and high stability. In this review, we first discussed the mechanisms of various Ir-based catalysts in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), including metal, alloys, and oxides. Important criteria and methods for precise evaluation of water splitting catalysts are discussed. Then, the applications of Ir-based nanomaterials in the HER, OER and the overall water splitting are comprehensively reviewed, with an emphasis on correlating the structure-function relationships and the advanced strategies for rational design of reaction-oriented Ir catalysts. Lastly, the current challenges in fundamental studies and future directions in this field are presented.
Chen, Z, Duan, X, Wei, W, Wang, S, Zhang, Z & Ni, B-J 2020, 'Boride-based electrocatalysts: Emerging candidates for water splitting', Nano Research, vol. 13, no. 2, pp. 293-314.
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© 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature. Electrocatalytic water splitting (EWS) is a promising route to produce hydrogen in a sustainable and environment-benign manner. To realize the large-scale hydrogen production, it is paramount to develop desirable electrocatalysts with engineered structure, high catalytic activity, facile accessibility, low cost, and good durability. Of late, boride-based materials, especially transition-metal borides (TMBs), are emerging as promising candidates for the EWS process. However, so far, little attempt has been made to provide a comprehensive summary on these findings. Herein, this review provides the up-to-date status on upgrading the catalytic performance of TMB-based nanomaterials by regulating the internal and external characteristics. The conventional synthetic techniques are first presented for the preparation of TMB-based catalysts. Afterwards, the advanced strategies are summarized to enhance the catalytic performance of TMBs, including morphology control, component regulation, phase engineering, surface oxidation and hybridization. Then, the design principles of TMB-based electrocatalysts for high-performance EWS are outlined. Lastly, the current challenges and future directions in the development of TMB-based materials are proposed. This review article is expected to envisage insights into the TMBs-based water splitting and to provide strategies for design of the next-generation TMB-based electrocatalysts. [Figure not available: see fulltext.].
Chen, Z, Ibrahim, I, Hao, D, Liu, X, Wu, L, Wei, W, Su, D & Ni, B-J 2020, 'Controllable design of nanoworm-like nickel sulfides for efficient electrochemical water splitting in alkaline media', Materials Today Energy, vol. 18, pp. 100573-100573.
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© 2020 Elsevier Ltd Developing cost-effective electrocatalysts for electrochemical water splitting (EWS) is appealing and challenging for sustainable water electrolysis. Currently, nickel sulfides are considered as promising candidates for EWS due to their low cost and high catalytic activity. However, the facile design of nickel sulfides with high catalytic performance is still highly demanded. In this study, we have developed a one-step solvothermal strategy to construct nickel sulfides as efficient water splitting catalysts. By taking advantage of the small size, abundant active sites, large electrochemical surface area, and good conductivity, the nanoworm-like nickel sulfides (NiS-NW/Ni foam [NF]) exhibit better oxygen evolution reaction performance (a low overpotential of 279 mV to achieve 100 mA cm−2, Tafel slope of 38.44 mV dce−1) than the nanoplate-like analogs, as well as most of reported nickel sulfide–based electrocatalysts. In addition, the NiS-NW/NF directly used as bifunctional electrodes for overall water splitting requires a low voltage of 1.563 V to attain a current density of 10 mA cm−2 with good long-term durability. This work provides a facile strategy for the design of efficient nickel sulfide-based electrocatalysts for energy conversion applications.
Chen, Z, Wu, G, Wu, Y, Wu, Q, Shi, Q, Ngo, HH, Vargas Saucedo, OA & Hu, H-Y 2020, 'Water Eco-Nexus Cycle System (WaterEcoNet) as a key solution for water shortage and water environment problems in urban areas', Water Cycle, vol. 1, pp. 71-77.
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Cheng, D, Hao Ngo, H, Guo, W, Wang Chang, S, Duc Nguyen, D, Liu, Y, Zhang, X, Shan, X & Liu, Y 2020, 'Contribution of antibiotics to the fate of antibiotic resistance genes in anaerobic treatment processes of swine wastewater: A review', Bioresource Technology, vol. 299, pp. 122654-122654.
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Antibiotic resistance genes (ARGs) in water environment have become a global health concern. Swine wastewater is widely considered to be one of the major contributors for promoting the proliferation of ARGs in water environments. This paper comprehensively reviews and discusses the occurrence and removal of ARGs in anaerobic treatment of swine wastewater, and contributions of antibiotics to the fate of ARGs. The results reveal that ARGs' removal is unstable during anaerobic processes, which negatively associated with the presence of antibiotics. The abundance of bacteria carrying ARGs increases with the addition of antibiotics and results in the spread of ARGs. The positive relationship was found between antibiotics and the abundance and transfer of ARGs in this review. However, it is necessary to understand the correlation among antibiotics, ARGs and microbial communities, and obtain more knowledge about controlling the dissemination of ARGs in the environment.
Cheng, D, Liu, Y, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Zhang, S, Luo, G & Liu, Y 2020, 'A review on application of enzymatic bioprocesses in animal wastewater and manure treatment', Bioresource Technology, vol. 313, pp. 123683-123683.
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Enzymatic processing has been considered an interesting technology as enzymes play important roles in the process of waste bioconversion, whilst heling to develop valuable products from animal wastes. In this paper, the application of enzymes in animal waste management were critically reviewed in short with respect to utilization in: (i) animal wastewater treatment and (ii) animal manure management. The results indicate that the application of enzymes could increase both chemical oxygen demand (COD) removal efficiency and production of biogas. The enzymatic bioprocesses were found to be affected by the type, source and dosage of enzymes and the operating conditions. Further studies on optimizing the operating conditions and developing cost-effective enzymes for the future large-scale application are therefore necessary.
Cheng, D, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Li, J, Ly, QV, Nguyen, TAH & Tran, VS 2020, 'Applying a new pomelo peel derived biochar in microbial fell cell for enhancing sulfonamide antibiotics removal in swine wastewater', Bioresource Technology, vol. 318, pp. 123886-123886.
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A sequential anode-cathode double-chamber microbial fuel cell (MFC) is a promising system for simultaneously removing contaminants, recovering nutrients and producing energy from swine wastewater. To improve sulfonamide antibiotics (SMs)'s removal in the continuous operating of MFC, one new pomelo peel-derived biochar was applied in the anode chamber in this study. Results demonstrated that SMs can be absorbed onto the heterogeneous surfaces of biochar through pore-filling and π-π EDA interaction. Adding biochar to a certain concentration (500 mg/L) could enhance the efficiency in removing sulfamethoxazole, sulfadiazine and sulfamethazine to 82.44-88.15%, 53.40-77.53% and 61.12-80.68%, respectively. Moreover, electricity production, COD and nutrients removal were improved by increasing the concentration of biochar. Hence, it is proved that adding biochar in MFC could effectively improve the performance of MFC in treating swine wastewater containing SMs.
Cheng, D, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Liu, Y, Shan, X, Nghiem, LD & Nguyen, LN 2020, 'Removal process of antibiotics during anaerobic treatment of swine wastewater', Bioresource Technology, vol. 300, pp. 122707-122707.
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High concentrations of antibiotics in swine wastewater pose potentially serious risks to the environment, human and animal health. Identifying the mechanism for removing antibiotics during the anaerobic treatment of swine wastewater is essential for reducing the serious damage they do to the environment. In this study, batch experiments were conducted to investigate the biosorption and biodegradation of tetracycline and sulfonamide antibiotics (TCs and SMs) in anaerobic processes. Results indicated that the removal of TCs in the anaerobic reactor contributed to biosorption, while biodegradation was responsible for the SMs' removal. The adsorption of TCs fitted well with the pseudo-second kinetic mode and the Freundlich isotherm, which suggested a heterogeneous chemisorption process. Cometabolism was the main mechanism for the biodegradation of SMs and the process fitted well with the first-order kinetic model. Microbial activity in the anaerobic sludge might be curtailed due to the presence of high concentrations of SMs.
Cheng, D, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Liu, Y, Wei, Q & Wei, D 2020, 'A critical review on antibiotics and hormones in swine wastewater: Water pollution problems and control approaches', Journal of Hazardous Materials, vol. 387, pp. 121682-121682.
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Swine wastewater (SW) is an important source of antibiotics and hormones (A&H) in the environment due to their large-scale application in swine industry. A&H in SW can be released into the water environment through the direct discharge of SW, effluent from SW treatment plants, and runoff and leaching from farmland polluted by swine wastes. The presence of A&H in the water environment has become an increasing global concern considering their adverse effects to the aquatic organism and human. This review critically discusses: (i) the occurrence of A&H in global water environment and their potential risks to water organisms and human; (ii) the management and technical approaches for reducing the emission of A&H in SW to the water environment. The development of antibiotic alternatives and the enhanced implementation of vaccination and biosecurity are promising management approaches to cut down the consumption of antibiotics during swine production. Through the comparison of different biological treatment technologies for removing A&H in SW, membrane-based bioprocesses have relatively higher and more stable removal efficiencies. Whereas, the combined system of bioprocesses and AOPs is expected to be a promising technology for elimination and mineralization of A&H in swine wastewater. Further study on this system is therefore necessary.
Cheng, D, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Zhang, X, Varjani, S & Liu, Y 2020, 'Feasibility study on a new pomelo peel derived biochar for tetracycline antibiotics removal in swine wastewater', Science of The Total Environment, vol. 720, pp. 137662-137662.
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Cheng, D, Ngo, HH, Guo, W, Lee, D, Nghiem, DL, Zhang, J, Liang, S, Varjani, S & Wang, J 2020, 'Performance of microbial fuel cell for treating swine wastewater containing sulfonamide antibiotics', Bioresource Technology, vol. 311, pp. 123588-123588.
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Cheng, H, Liu, Y, Huang, D, Pan, Y & Wang, Q 2020, 'Adaptive Transfer Learning of Cross-Spatiotemporal Canonical Correlation Analysis for Plant-Wide Process Monitoring', Industrial & Engineering Chemistry Research, vol. 59, no. 49, pp. 21602-21614.
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© Multivariate statistical methods have gained significant popularity in past decades. However, process dynamics and insufficient training data usually result in degradation or even failure of a trained model. To deal with these problems, this paper proposes a novel process monitoring method, called cross-spatiotemporal adaptive boosting transfer learning (CS-AdBoostTrLM). Different from the standard methods, CS-AdBoostTrLM has the following advantages: first, source domain (SD) data, which are discarded by the factory, can be re-enabled to alleviate the issue of insufficient training data. Second, cross-spatiotemporal canonical correlation analysis is proposed to achieve the domain adaptation between the SD data and target domain data, so as to overcome the negative transfer. Third, the particle swarm optimization algorithm is used to optimize the local detection model, in such a way that the integrated detection model can converge to the optimality globally. Finally, the data from the wastewater treatment plant and chemical plant are analyzed to demonstrate the effectiveness of the proposed method.
Cheshomi, A, Bakhtiyari, E & Khabbaz, H 2020, 'A comparison between undrained shear strength of clayey soils acquired by “PMT” and laboratory tests', Arabian Journal of Geosciences, vol. 13, no. 14, p. 640.
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© 2020, Saudi Society for Geosciences. A pressuremeter test (PMT) is one of the in situ tests, which is used to evaluate deformation and strength parameters of soils for various projects, including subway projects. The limit pressure (PL) and undrained shear strength (Su) are the key parameters that are obtained directly and indirectly from the pressuremeter testing results. This research was carried out using geotechnical information obtained from a subway project in Qom city, Iran. Based on 44 PMT and uniaxial tests on very stiff to hard saturated clayey soils, a linear empirical equation between Su − PL and Su − PL* = (PL − σH) with R2 = 0.68 was proposed and it was found that σH had an insignificant effect on the proposed relationship. The effect of physical properties of soil, including plastic index (PI), liquid limit (LL), and water content (ω), was evaluated, and a multivariate equation was proposed between them. A comparison between the equations obtained in this research and those proposed by other researchers reveals that the empirical relationships between Su and PL are associated with the consistency of soils; the stiffer the soil is, the slope of relationship between Su and PL is less.
Choi, Y, Naidu, G, Lee, S & Vigneswaran, S 2020, 'Recovery of sodium sulfate from seawater brine using fractional submerged membrane distillation crystallizer', Chemosphere, vol. 238, pp. 124641-124641.
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Seawater reverse osmosis (SWRO) brine contain many valuable resources. In this study, fractional-submerged membrane distillation crystallizer (F-SMDC) was used to recover sodium sulfate (Na2SO4) from SWRO brine. The concentration/temperature gradient (CG/TG) in the reactor enhanced water recovery utilizing MD and Na2SO4 crystallization via a crystallizer. Crystals were not obtained at the bottom section of the F-SMDC due to: firstly, calcium sulfate crystallization occurring on the membrane surface; and secondly, low temperature-sensitivity solubility component such as NaCl exerting a negative influence. In order to obtain supersaturation, a sulfate-rich scenario was created in the reactor through the addition of the following three components: Na2SO4, MgSO4 and (NH4)2SO4. When Na2SO4 and MgSO4 were added, a larger concentration was observed at the top section, resulting in a low concentration gradient (CG) ratio, i.e. around 1.7. Conversely, the addition of (NH4)2SO4 achieved faster Na2SO4 crystallization (VCF 1.42) at the bottom section with a greater CG ratio of more than 2.0. Total water recovery ratio of 72% and 223.73 g Na2SO4 crystals were successfully extracted from simulated SWRO brine using laboratory scale F-SMDC.
Choo, Y, Halat, DM, Villaluenga, I, Timachova, K & Balsara, NP 2020, 'Diffusion and migration in polymer electrolytes', Progress in Polymer Science, vol. 103, pp. 101220-101220.
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Mixtures of neutral polymers and lithium salts have the potential to serve as electrolytes in next-generation rechargeable Li-ion batteries. The purpose of this review is to expose the delicate interplay between polymer-salt interactions at the segmental level and macroscopic ion transport at the battery level. Since complete characterization of this interplay has only been completed in one system: mixtures of poly(ethylene oxide) and lithium bis(trifluoromethanesulfonyl)imide (PEO/LiTFSI), we focus on data obtained from this system. We begin with a discussion of the activity coefficient, followed by a discussion of six different diffusion coefficients: the Rouse motion of polymer segments is quantified by Dseg, the self-diffusion of cations and anions is quantified by Dself,+ and Dself,−, and the build-up of concentration gradients in electrolytes under an applied potential is quantified by Stefan-Maxwell diffusion coefficients, D0+, D0-, and D+-. The Stefan-Maxwell diffusion coefficients can be used to predict the velocities of the ions at very early times after an electric field is applied across the electrolyte. The surprising result is that D0- is negative in certain concentration windows. A consequence of this finding is that at these concentrations, both cations and anions are predicted to migrate toward the positive electrode at early times. We describe the controversies that surround this result. Knowledge of the Stefan-Maxwell diffusion coefficients enable prediction of the limiting current. We argue that the limiting current is the most important characteristic of an electrolyte. Excellent agreement between theoretical and experimental limiting current is seen in PEO/LiTFSI mixtures. What sequence of monomers that, when polymerized, will lead to the highest limiting current remains an important unanswered question. It is our hope that the approach presented in this review will guide the development of such polymers.
Chowdhury, FR, Hoque, A, Chowdhury, FUH, Amin, MR, Rahim, A, Rahman, MM, Yasmin, R, Amin, MR, Miah, MT, Kalam, MA & Rahman, MS 2020, 'Convalescent plasma transfusion therapy in severe COVID-19 patients- a safety, efficacy and dose response study: A structured summary of a study protocol of a phase II randomized controlled trial', Trials, vol. 21, no. 1.
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AbstractObjectivesGeneral: To assess the safety, efficacy and dose response of convalescent plasma (CP) transfusion in severe COVID-19 patientsSpecific:a. To identify the appropriate effective dose of CP therapy in severe patientsb. To identify the efficacy of the therapy with their end point based on clinical improvement within seven days of treatment or until discharge whichever is later and in-hospital mortalityc. To assess the clinical improvement after CP transfusion in severe COVID-19 patientsd. To assess the laboratory improvement after CP transfusion in severe COVID-19 patientsTrial DesignThis is a multicentre, multi-arm phase II Randomised Controlled Trial.ParticipantsAge and sex matched COVID-19 positive (by RT-PCR) severe cases will be enrolled in this trial. Severe case is defined by the World Health Organization (W.H.O) clinical case definition. The inclusion criteria are1. Respiratory rate > 30 breaths/min; PLUS2. Severe respiratory distress; or SpO2 ≤ 88% on room air or PaO2/FiO2≤ 300 mm of Hg, PLUS3. Radiological (X-ray or CT scan) evidence of bilateral lung infiltrate, AND OR4. Systolic BP < 90 mm of Hg or diastolic BP <60 mm of Hg.AND/OR5. Criteria 1 to 4 AND or patient in ventilator supportPatients’ below18 years, pregnant and lactating women, previous history of allergic reaction to plasma, patients who have already received plasma from a different source will be excluded. Patients will be enrolled at Bangabandhu Sheikh Mujib Medical University (BSMMU) hospital, Dhaka medical college hospital (DMCH) and Mugda medic...
Chowdhury, MA, Shuvho, MBA, Hossain, MI, Ali, MO, Kchaou, M, Rahman, A, Yeasmin, N, Khan, AS, Rahman, MA & Mofijur, M 2020, 'Multiphysical analysis of nanoparticles and their effects on plants', Biotechnology and Applied Biochemistry.
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Nanoparticles are the magic bullets and at the leading edge in the field of nanotechnology, and their unique properties make these materials indispensable and superior in many areas, including the electronic field. Extensive applications of nanomaterials are incontrovertibly entering our living system. The increasing use of nanomaterials into the ecosystem is one of the crucial environmental factors that human being is facing. Nanomaterials raise noticeable toxicological concerns; particularly their accumulation in plants and the resultant toxicity may affect the food chain. Here, we analyzed the characterization of nanomaterials, such as graphene, Al2 O3 , TiO2 , and semi-insulating or conducting nanoparticles. Quantitative evaluation of the nanomaterials was conducted and their commercialization aspects were discussed. Various characterization techniques, scanning electron microscopy, X-ray diffraction, and ultraviolet rays were utilized to identify the morphology, phase, absorbance, and crystallinity. In addition, we analyzed the effects of nanomaterials on plants. The toxicity of nanoparticles has severe effects on loss of morphology of the plants. Potential mechanisms including physical and physiological effects were analyzed. In future studies, it is indispensable to assess widely accepted toxicity evaluation for safe production and use of nanomaterials.
Chu-Van, T, Surawski, N, Ristovski, Z, Yuan, C-S, Stevanovic, S, Ashrafur Rahman, SM, Hossain, FM, Guo, Y, Rainey, T & Brown, RJ 2020, 'The effect of diesel fuel sulphur and vanadium on engine performance and emissions', Fuel, vol. 261, pp. 116437-116437.
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© 2019 Elsevier Ltd Metallic composition of diesel particulate matter, even though a relatively small proportion of total mass, can reveal important information regarding engine conditions, fuel/lubricating oil characteristics and for health impacts. In this study, a detailed investigation into the metallic elemental composition at different particle diameter sizes has been undertaken. A bivariate statistical analysis was performed in order to investigate the correlation between the metallic element, measured engine performance and engine emission variables. Major sources of metallic elements in the emitted particles are considered in this study, including the fuel and lubricating oil compositions, engine wear emissions and metal-containing dust in the ambient air. Metallic solid ultrafine-particles (Dp < 100 nm) are strongly associated with metallic compounds derived from lubricating oil (Ca, Zn, Mg and K), while the fuel related metallic compounds and engine wear emissions are represented in the accumulation mode particle fraction (>100 nm). Calculated correlation matrices show a clear effect of engine load conditions and fuel S contents on particle number and mass emissions.
Clark, JS, Poore, AGB, Coleman, MA & Doblin, MA 2020, 'Local Scale Thermal Environment and Limited Gene Flow Indicates Vulnerability of Warm Edge Populations in a Habitat Forming Macroalga', Frontiers in Marine Science, vol. 7.
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© Copyright © 2020 Clark, Poore, Coleman and Doblin. Species inhabiting warm-edge populations of their distribution are suggested to be at the forefront of global warming due to reduced fitness, limited gene flow and living close to their physiological thermal limits. Determining the scale that governs thermal niche and the functional responses of habitat-forming species to environmental stressors is critical for successful conservation efforts, particularly as coastal ecosystems are impacted by global change. Here, we examine the susceptibility of warm-edge populations to warming, in the habitat-forming macroalga, Hormosira banksii, from south-eastern Australia. We use a quantitative breeding design to quantify intraspecific variation in thermal performance (growth, ontogenic development and photosynthetic efficiency) of different genotypes sourced from sites at the equatorward distributional edge (warm-edge) and those toward the center of its distribution (non-edge). The genetic diversity and structure of H. banksii was also examined using microsatellite markers amongst the same sites. Our results found variable responses in thermal performance for growth and development. Warm-edge germlings grew optimally in lower temperatures tested and had narrower thermal breadth compared to non-edge germlings which grew in higher and more broader temperatures. Warm-edge germlings however, showed greater plasticity to tolerate high light indicated by a greater proportion of energy being dissipated as regulated non-photochemical quenching [Y(NPQ)] than non-regulated non-photochemical quenching [Y(NO)]. Overall genetic diversity was lower at the warm-edge location with evidence of increased structuring and reduced gene flow in comparison to the non-edge location. Evidence of genetic structuring was not found locally between high and low shore within sites. Together, these data suggest that non-edge populations may be “thermally buffered” from increased temperatures associated...
Collins, S, Boyd, PW & Doblin, MA 2020, 'Evolution, Microbes, and Changing Ocean Conditions', Annual Review of Marine Science, vol. 12, no. 1, pp. 181-208.
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Experimental evolution and the associated theory are underutilized in marine microbial studies; the two fields have developed largely in isolation. Here, we review evolutionary tools for addressing four key areas of ocean global change biology: linking plastic and evolutionary trait changes, the contribution of environmental variability to determining trait values, the role of multiple environmental drivers in trait change, and the fate of populations near their tolerance limits. Wherever possible, we highlight which data from marine studies could use evolutionary approaches and where marine model systems can advance our understanding of evolution. Finally, we discuss the emerging field of marine microbial experimental evolution. We propose a framework linking changes in environmental quality (defined as the cumulative effect on population growth rate) with population traits affecting evolutionary potential, in order to understand which evolutionary processes are likely to be most important across a range of locations for different types of marine microbes.
Commault, AS, Kaur Walia, N, Fabris, M, Barolo, L, Siboni, N, Adriaans, J, Ralph, PJ & Pernice, M 2020, 'Effect of biphasic temperature regime on therapeutic recombinant protein production in the green alga Chlamydomonas reinhardtii', Algal Research, vol. 50, pp. 101997-101997.
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© 2020 Elsevier B.V. Microalgae are increasingly being considered for recombinant protein production because of low cultivation costs, absence of endotoxins and insusceptibility to human infectious agents. Despite these advantages, the yield of recombinant protein produced in microalgae is still low compared to more established expression systems and optimization at the genetic and cultivation levels is required for this new system to be economically viable. This study investigates the effect of biphasic temperature regimes on the yield of recombinant human interferon alpha 2a (IFN-α2a), a therapeutic protein known for its anti-cancer and anti-viral properties, produced by the model green alga Chlamydomonas reinhardtii (Cr.IFN-α2a). Biphasic growth is commonly employed to increase recombinant protein production in mammalian cell lines used for commercial production of therapeutic proteins, with a lowering of the temperature resulting in higher yields. In this study, lowering the temperature from 25 °C to 15 °C in mid-exponential growth phase increased the accumulation of Cr.IFN-α2a by 3.3-fold while it slowed down the growth of the three C. reinhardtii transgenic lines tested. In contrast, a rise of temperature from 25 °C to 35 °C accelerated cell growth, while negatively impacting the production of Cr.IFN-α2a. After a two-step chromatography purification, the Cr.IFN-α2a produced was estimated to be 53% pure with a yield of 90 μg/L of culture. The amino acid sequence of Cr.IFN-α2a was confirmed by mass spectrometry. However, the anti-viral activity of Cr.IFN-α2a was found to be 10 times lower than the human IFN-α2a standard produced using E. coli when challenged in a cytopathic effect (CPE) assay, likely due to the formation of aggregates. While the molecular mechanisms driving the accumulation of Cr.IFN-α2a at lower temperature remains unclear, our results support that reducing the temperature at the peak of expression is a valid strategy to increase the yield o...
Cong Nguyen, N, Cong Duong, H, Chen, S-S, Thi Nguyen, H, Hao Ngo, H, Guo, W, Quang Le, H, Cong Duong, C, Thuy Trang, L, Hoang Le, A, Thanh Bui, X & Dan Nguyen, P 2020, 'Water and nutrient recovery by a novel moving sponge – Anaerobic osmotic membrane bioreactor – Membrane distillation (AnOMBR-MD) closed-loop system', Bioresource Technology, vol. 312, pp. 123573-123573.
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For the first time, a novel sponge-based moving bed-anaerobic osmosis membrane bioreactor/membrane distillation (AnOMBR/MD) system using mixed Na3PO4/EDTA-2Na as the draw solution was employed to treat wastewater for enhanced water flux and reduced membrane fouling. Results indicated that the moving sponge-AnOMBR/MD system obtained a stable water flux of 4.01 L/m2 h and less membrane fouling for a period lasting 45 days. Continuous moving sponge around the FO module is the main mechanism for minimizing membrane fouling during the 45-day AnOMBR operation. The proposed system's nutrient removal was almost 100%, thus showing the superiority of simultaneous FO and MD membranes. Nutrient recovery from the MF permeate was best when solution pH was controlled to 9.5, whereby 17.4% (wt/wt) of phosphorus was contained in precipitated components. Moreover, diluted draw solute following AnOMBR was effectively regenerated using the MD process with water flux above 2.48 L/m2 h and salt rejection > 99.99%.
Cui, Z, Hao Ngo, H, Cheng, Z, Zhang, H, Guo, W, Meng, X, Jia, H & Wang, J 2020, 'Hysteresis effect on backwashing process in a submerged hollow fiber membrane bioreactor (MBR) applied to membrane fouling mitigation', Bioresource Technology, vol. 300, pp. 122710-122710.
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Hysteresis effect on backwashing in a submerged MBR was investigated with dead-end hollow fiber membranes. The out-of-step changes in TMP and flux is the real hysteresis effect which is common but easily overlooked. Methods of visualization and ultrasonic spectrum analysis were implemented. The results showed that fouling layer is just the culprit of hysteresis effect. Fouling level and fiber length were determined as two key factors that affect hysteresis effect by data and model derivation. Moreover, a hysteresis evaluation index "τbw" is proposed to quantify the result of TMP vs time. The relationship between influence factors and "τbw" is interactive. A linear relationship between fouling level and "τbw" was found as well as an extreme value between fiber length and "τbw". A lower fouling level (lower backwashing flow) and optimal backwashing duration will be helpful for an effective backwashing no matter for membrane fouling control or energy cost reduce.
Dadol, GC, Kilic, A, Tijing, LD, Lim, KJA, Cabatingan, LK, Tan, NPB, Stojanovska, E & Polat, Y 2020, 'Solution blow spinning (SBS) and SBS-spun nanofibers: Materials, methods, and applications', Materials Today Communications, vol. 25, pp. 101656-101656.
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© 2020 Elsevier Ltd Solution blow spinning (SBS) is a maturing nanofiber fabrication technology. Over the past decade, there has been a growing interest in employing and developing this facile method of fabricating nanofibers, sourced from different materials to suit varied applications. For the first time, this review will provide a comprehensive overview of solution blow spinning, including the principles, materials, methods, and applications. We start with the principles of the SBS method, followed by a detailed account of the different precursor polymers (i.e., synthetic, biocompatible, and bio-based materials) and composites that have been used in the SBS of nanofibers. The proceeding section presents the known applications of nanofibers obtained through SBS which are discussed primarily in the areas of energy and electronics, biomedical, environmental, membrane separation, and, textile and smart material applications. We highlight the most important and recent advances related to SBS over the last ten years. Lastly, we give perspectives, challenges, opportunities, and new directions of the SBS technology.
Daer, S, Akther, N, Wei, Q, Shon, HK & Hasan, SW 2020, 'Influence of silica nanoparticles on the desalination performance of forward osmosis polybenzimidazole membranes', Desalination, vol. 491, pp. 114441-114441.
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© 2020 Elsevier B.V. Polybenzimidazole (PBI) is a chemically and thermally stable polymer, which is being considered for forward osmosis (FO) seawater desalination in regions with high seawater temperatures and salinities. In this work, FO flat sheet membranes were fabricated using non-solvent induced phase separation (NIPS) method from PBI dope solution incorporated with silica nanoparticles (SNPs) at different concentrations (0, 0.5, 1 and 2 wt%). The influence of draw solution concentration, cross-flow velocity and membrane cell orientation on the performance of pristine PBI and PBI/SNP membranes was examined. Results showed that the performance of the PBI/SNP membranes improved compared to the pristine PBI membrane. Addition of 0.5 wt% of SNPs to PBI membranes (S0.5) reduced the membrane's structural parameter (809.4 μm vs. 1193.2 μm), augmented the tensile strength (31.9 MPa vs. 27.3 MPa), and increased water flux by two folds (16.9 Lm−2 h−1 vs. 7.4 Lm−2 h−1) compared to the pristine PBI membrane (S0). Given the thermal stability of the PBI/SNP membrane along with its improved water permeation performance, the modified membrane offers a promising option for the FO process in hot and arid zones.
Dang, LC, Dang, CC & Khabbaz, H 2020, 'Modelling of columns and fibre-reinforced load-transfer platform-supported embankments', Proceedings of the Institution of Civil Engineers - Ground Improvement, vol. 173, no. 4, pp. 197-215.
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A novel ground modification technique is proposed utilising a fibre-reinforced load-transfer platform (FRLTP) and deep cement mixing column-supported (CS) embankment constructed over soft soils. An equivalent two-dimensional finite-element model was developed to simulate the full geometry of a CS embankment reinforced without or with an FRLTP. A series of numerical analyses was first conducted on the proposed model for different improvement depths to assess the effectiveness of the introduction of FRLTP into the CS embankment system in terms of total and differential settlements, the stress-transfer mechanism and lateral displacement with depth. Subsequently, another extensive parametric study was conducted to further investigate the influence of the FRLTP key parameters, including elastic deformation modulus, shear strength properties and tensile strength, on the embankment performance during construction and consolidation time. The numerical results showed that the FRLTP effectively diminished the total settlement and the lateral deformation of the embankment, while improving the stress concentration ratio and the embankment stability to a great extent. The findings of the extensive parametric study indicate that the FRLTP's shear strength properties appear to be the most influential factors to be considered in the design procedure of a target CS–FRLTP–embankment system.
Deng, L, Guo, W, Ngo, HH, Wang, XC, Hu, Y, Chen, R, Cheng, D, Guo, S & Cao, Y 2020, 'Application of a specific membrane fouling control enhancer in membrane bioreactor for real municipal wastewater treatment: Sludge characteristics and microbial community', Bioresource Technology, vol. 312, pp. 123612-123612.
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Ding, A, Zhao, Y, Ngo, HH, Bai, L, Li, G, Liang, H, Ren, N & Nan, J 2020, 'Metabolic uncoupler, 3,3′,4′,5-tetrachlorosalicylanilide addition for sludge reduction and fouling control in a gravity-driven membrane bioreactor', Frontiers of Environmental Science & Engineering, vol. 14, no. 6.
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© 2020, Higher Education Press. The gravity-driven membrane bioreactor (MBR) system is promising for decentralized sewage treatment because of its low energy consumption and maintenance requirements. However, the growing sludge not only increases membrane fouling, but also augments operational complexities (sludge discharge). We added the metabolic uncoupler 3,3′,4′,5-tetrachlorosalicylanilide (TCS) to the system to deal with the mentioned issues. Based on the results, TCS addition effectively decreased sludge ATP and sludge yield (reduced by 50%). Extracellular polymeric substances (EPS; proteins and polysaccharides) decreased with the addition of TCS and were transformed into dissolved soluble microbial products (SMPs) in the bulk solution, leading to the break of sludge flocs into small fragments. Permeability was increased by more than two times, reaching 60–70 L/m2/h bar when 10–30 mg/L TCS were added, because of the reduced suspended sludge and the formation of a thin cake layer with low EPS levels. Resistance analyses confirmed that appropriate dosages of TCS primarily decreased the cake layer and hydraulically reversible resistances. Permeability decreased at high dosage (50 mg/L) due to the release of excess sludge fragments and SMP into the supernatant, with a thin but more compact fouling layer with low bioactivity developing on the membrane surface, causing higher cake layer and pore blocking resistances. Our study provides a fundamental understanding of how a metabolic uncoupler affects the sludge and bio-fouling layers at different dosages, with practical relevance for in situ sludge reduction and membrane fouling alleviation in MBR systems. [Figure not available: see fulltext.].
Do, MH, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Deng, L, Chen, Z & Nguyen, TV 2020, 'Performance of mediator-less double chamber microbial fuel cell-based biosensor for measuring biological chemical oxygen', Journal of Environmental Management, vol. 276, pp. 111279-111279.
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Recently, the microbial fuel cell-based biosensor has been considered as an attractive technology for measuring wastewater quality such as biochemical oxygen demand (BOD). In this study, a mediator-less double compartment MFC based biosensor utilizing carbon felt as an anode electrode and inoculated with mixed culture was developed to improve the real application of a rapid BOD detection. This study aims to: (i) establish the effect of the operating conditions (i.e., pH, external resistance, fuel feeding rate) on MFC performance; (ii) investigate the correlation between biochemical oxygen demand (BOD) and signal output, and (iii) evaluate the operational stability of the biosensor. The presented result reveals that the maximum current and power production was obtained while 100 mM NaCl and 50 mM Phosphate buffer saline was used as a catholyte solution, neutral pH condition of media and fuel feeding rate at 0.3 mL min-1. Notably, a wider range of BOD concentration up to 300 mg L -1 can be obtained with the voltage output (R2 > 0.9901). Stable and steady power was produced by running MFC in 30 days when cells operated at 1000 Ω external resistance. Our research has some competition with the previous double chamber MFC in the upper limit of BOD detection. This results might help to increase the real application of MFC based BOD biosensor in real-time measurement.
Do, MH, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Liu, Y, Varjani, S & Kumar, M 2020, 'Microbial fuel cell-based biosensor for online monitoring wastewater quality: A critical review', Science of The Total Environment, vol. 712, pp. 135612-135612.
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© 2019 Elsevier B.V. Recently, the application of the microbial fuel cell (MFC)-based biosensor for rapid and real-time monitoring wastewater quality is very innovative due to its simple compact design, disposability, and cost-effectiveness. This review represents recent advances in this emerging technology for the management of wastewater quality, where the emphasis is on biochemical oxygen demand, toxicity, and other environmental applications. In addition, the main challenges of this technology are discussed, followed by proposing possible solutions to those challenges based on the existing knowledge of detection principles and signal processing. Potential future research of MFC-based biosensor has been demonstrated in this review.
Doan, S & Fatahi, B 2020, 'Analytical solution for free strain consolidation of stone column-reinforced soft ground considering spatial variation of total stress and drain resistance', Computers and Geotechnics, vol. 118, pp. 103291-103291.
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© 2019 Elsevier Ltd This paper provides an analytical solution for consolidation problem of a stone column-improved soft soil layer subjected to an instantly applied loading under free strain condition. The radial and vertical consolidation equations are solved in a coupled fashion for both the stone column and its surrounding soil. A general solution of excess pore water pressure at any point of a unit cell model in terms of a Fourier-Bessel series was achieved using the combination of separation of variables method and orthogonal expansion technique. The obtained solution can capture the drain (well) resistance effect and the space-dependent distribution of total vertical stress induced by the external loading. Indeed, since the permeability and size of the stone column are directly utilised in the governing equations and the analytical solution, the drain resistance is directly captured. The capabilities of the proposed solution are exhibited through a comprehensive worked example, while the accuracy of the solution is verified against a finite element simulation and field measurements of a case history with good agreements. To examine the effect of various factors on consolidation behaviour of the composite ground, a parametric study involving column spacing, modulus and permeability of soft soil along with distribution pattern of total stress and thickness of soil layer is also conducted. A decrease in the column spacing or an increase in the modulus or permeability of soft soil led to the acceleration of the consolidation process of the soil region, while the variation of the total stress with depth and the thickness of soil deposit primarily affected the consolidation rate of stone column. Under the free strain condition, the average differential settlement between the stone column and encircling soil was indeed considerable during the consolidation process.
Dong, Y & Fatahi, B 2020, 'Discrete element simulation of cavity expansion in lightly cemented sands considering cementation degradation', Computers and Geotechnics, vol. 124, pp. 103628-103628.
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© 2020 Elsevier Ltd This study aims to investigate the influence of cementation on the stress-strain and strength characteristics of soil during cavity expansion in lightly cemented sand deposit using three-dimensional discrete element simulations. Contact models, simulating the cementation effects of bonded clumps and capturing the interlocking effects between discrete sand particles, are incorporated to mimic the cemented sands with various cement contents. The microscopic parameters are calibrated and validated against existing experimental results. Real scale cylindrical cavity expansion models starting from zero initial cavity radius with different levels of cementation are developed, and each proposed model consists of 150,000 particles with boundary conditions carefully selected to reproduce the realistic scenario. The embedded scripting is utilised to precisely measure both the local and global stress–strain variations, and record and analyse the cementation bond breakage during the cavity expansion process. The results confirm that the cementation enhances the material strength through the increase in cohesion and tensile strength at the contacting interfaces, whereas the friction angle is not altered notably. Hence, the failure envelope of the cemented sand gradually merges with the critical state line due to the cementation degradation, particularly at a high confining pressure. It was found that the failure mode of the lightly cemented sand adopted in this study, was mainly controlled by the shear rather than tensile strength at the contacting interfaces. Referring to the numerical predictions it is evident that the zone with significant cementation degradation due to the cavity expansion extends as far as 4af for all cemented specimens (af being the final cavity radius). In addition, specimens with higher cement content experience a more pronounced dilation at the internal cavity wall, while an inverse trend is captured at a greater radial ...
Dong, Y, Fatahi, B & Khabbaz, H 2020, 'Three dimensional discrete element simulation of cylindrical cavity expansion from zero initial radius in sand', Computers and Geotechnics, vol. 117, pp. 103230-103230.
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© 2019 Elsevier Ltd This study seeks to assess the influence of choice of initial cavity radius on the soil response during cavity expansion in sandy soil adopting three-dimensional discrete element simulations and obtaining the size of the influence zone when the expansion starts from zero initial radius. Sandy soil is modelled adopting rolling resistance contact model to capture the effects of particle interlocking, and the microscopic parameters are calibrated utilising linear model deformability method for both loose and dense sands against experimental results. Four cylindrical cavity expansions that commenced from different initial radii are simulated in dense and loose sand specimens. The large-scale three-dimensional model is proposed with more than 500,000 particles, enabling precise volumetric dilation and contraction predictions using strain rate tensors. During the cavity expansion process, cavity pressure is constantly recorded by appropriate subroutines, while the stress-strain and void ratio variations are continuously monitored using an array of prediction spheres situated close to the internal cavities. The results confirm that the initial cavity radius chosen has conspicuous effects on the cavity pressure, the stress path, the volumetric strain and the deviatoric stress, especially at the initial stage of expansion; however, these effects become less pronounced and are ultimately minor as the cavity reaches full expansion. The results confirmed that given the same expansion volume, the pressure required to create a cavity is significantly larger than expanding an existing cavity in the same soil medium, whereas the pressure needed to maintain an already expanded cavity is not sensitive to the choice of initial cavity radius. The results obtained were further validated adopting the variations of stress path, deviatoric stress and volumetric strain in the vicinity of the cavity wall. The findings from this study may provide practicing en...
Dorji, P, Kim, DI, Hong, S, Phuntsho, S & Shon, HK 2020, 'Pilot-scale membrane capacitive deionisation for effective bromide removal and high water recovery in seawater desalination', Desalination, vol. 479, pp. 114309-114309.
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© 2020 Although seawater desalination is becoming an important technology for freshwater production, the presence of a high concentration of bromide in the seawater presents a major challenge. Bromide is one of the major inorganic precursors for the formation of disinfection by-products such as bromate, which is highly regulated due to its toxicity and carcinogenicity. Hence, a significant reduction of bromide ions is required prior to water disinfection. In Australia, all the desalination plants have to operate a two-stage reverse osmosis system to ensure effective bromide removal, which adds significant cost to the desalination system. In this study, a pilot-scale membrane capacitive deionisation (MCDI) was investigated as a potential alternative to the 2nd stage RO in seawater desalination. Moreover, strategies to enhance water recovery in MCDI was also carried out by using lower flow rates and shorter duration during the desorption stage. In order to reduce energy consumption in MCDI, a combined short-circuit and reverse polarity desorption is introduced. The results showed that MCDI can effectively remove bromide and dissolved salt at a much lower energy consumption compared with membrane process and that MCDI can be operated to achieve high water recovery without increasing the total energy consumption.
Duan, H, Gao, S, Li, X, Ab Hamid, NH, Jiang, G, Zheng, M, Bai, X, Bond, PL, Lu, X, Chislett, MM, Hu, S, Ye, L & Yuan, Z 2020, 'Improving wastewater management using free nitrous acid (FNA)', Water Research, vol. 171, pp. 115382-115382.
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Free nitrous acid (FNA), the protonated form of nitrite, has historically been an unwanted substance in wastewater systems due to its inhibition on a wide range of microorganisms. However, in recent years, advanced understanding of FNA inhibitory and biocidal effects on microorganisms has led to the development of a series of FNA-based applications that improve wastewater management practices. FNA has been used in sewer systems to control sewer corrosion and odor; in wastewater treatment to achieve carbon and energy efficient nitrogen removal; in sludge management to improve the sludge reduction and energy recovery; in membrane systems to address membrane fouling; and in wastewater algae systems to facilitate algae harvesting. This paper aims to comprehensively and critically review the current status of FNA-based applications in improving wastewater management. The underlying mechanisms of FNA inhibitory and biocidal effects are also reviewed and discussed. Knowledge gaps and current limitations of the FNA-based applications are identified; and perspectives on the development of FNA-based applications are discussed. We conclude that the FNA-based technologies have great potential for enhancing the performance of wastewater systems; however, further development and demonstration at larger scales are still required for their wider applications.
Duan, H, van den Akker, B, Thwaites, BJ, Peng, L, Herman, C, Pan, Y, Ni, B-J, Watt, S, Yuan, Z & Ye, L 2020, 'Mitigating nitrous oxide emissions at a full-scale wastewater treatment plant', Water Research, vol. 185, pp. 116196-116196.
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Mitigation of nitrous oxide (N2O) emissions is of primary importance to meet the targets of reducing carbon footprints of wastewater treatment plants (WWTPs). Despite of a large amount of N2O mitigation studies conducted in laboratories, full-scale implementation of N2O mitigation is scarce, mainly due to uncertainties of mitigation effectiveness, validation of N2O mathematical model, risks to nutrient removal performance and additional costs. This study aims to address the uncertainties by investigating the quantification, development and implementation of N2O mitigation strategies at a full-scale sequencing batch reactor (SBR). To achieve this, N2O emission dynamics, nutrient removal performance and operation of the SBR were monitored to quantify N2O emissions, and identify the N2O generation mechanisms. N2O mitigation strategies centered on reducing dissolved oxygen (DO) levels were consequently proposed and evaluated using a multi-pathway N2O production mathematical model before implementation. The implemented mitigation strategy resulted in a 35% reduction in N2O emissions (from the emission factor of 0.89 ± 0.05 to 0.58 ± 0.06%), which was equivalent to annual reduction of 2.35 tonne of N2O from the studied WWTP. This could be mainly attributed to reductions in N2O generated via the NH2OH oxidation pathway due to the lowering of DO level. As the first reported mitigation strategy permanently implemented at a full scale WWTP, it showcased that the mitigation of N2O emissions at full-scale is feasible and that widely accepted N2O mitigation strategies developed in laboratory studies are also likely effective in full-scale plants. Furthermore, the close agreement between the validated and predicted N2O emission factors (0.58% vs 0.55%, respectively), showed that the ...
Duong, HC, Ansari, AJ, Cao, HT, Nguyen, NC, Do, K-U & Nghiem, LD 2020, 'Membrane distillation regeneration of liquid desiccant solution for air-conditioning: Insights into polarisation effects and mass transfer', Environmental Technology & Innovation, vol. 19, pp. 100941-100941.
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© 2020 Membrane distillation (MD) embodies ideal attributes for the regeneration of liquid desiccant solutions used in air-conditioning systems. The MD process has been experimentally proven technically viable for the regeneration of liquid desiccant solutions; however, it suffers severely from temperature and concentration polarisation effects. In this study, for the first time a descriptive mass and heat transfer (DMHT) model is developed to quantitatively describe the mass transfer and the negative impacts of temperature and concentration polarisation during the MD regeneration of the LiCl desiccant solution. The simulation results demonstrate significant reduction in water flux along the membrane due to decreasing mass transfer coefficient (Cm) and transmembrane water vapour pressure gradient (ΔPm). Over the length of the membrane leaf of 0.145 m, water flux reduces by 31% from 11.0 to 7.6 L/m2⋅h. The temperature and concentration polarisation effects cause a substantial decline in the process driving force - ΔPm is only two thirds of the water vapour pressure difference between the bulk feed and distillate (ΔPb). Temperature polarisation is the predominant cause of the reduction in ΔPm compared with ΔPb; however, the negative impact of concentration polarisation is also notable. Finally, amongst the key operating conditions, the inlet feed temperature and concentration exert the most profound influence on the temperature and concentration polarisation during the DCMD regeneration of the hyper saline LiCl solution.
Duong, HC, Ansari, AJ, Hailemariam, RH, Woo, YC, Pham, TM, Ngo, LT, Dao, DT & Nghiem, LD 2020, 'Membrane Distillation for Strategic Water Treatment Applications: Opportunities, Challenges, and Current Status', Current Pollution Reports, vol. 6, no. 3, pp. 173-187.
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© 2020, Springer Nature Switzerland AG. Purpose of Review: Membrane distillation (MD) has been known as a promising water treatment process for many years. However, despite its advantages, MD has never been able to compete with other processes for industrial water treatment and supply. Instead, it has been orientated towards several unique strategic water treatment applications. This review aims to uncover the opportunities and technical challenges pertinent to the MD process and the current status of its strategic water treatment applications most notably including decentralised small-scale desalination for fresh water provision in remote areas, hybridisation with forward osmosis (FO) for treatment of challenging polluted waters, regeneration of liquid desiccant solutions for air conditioning, and treatment of acid effluents for beneficial reuse. Recent Findings: Pilot and small-scale MD systems have been demonstrated for decentralised desalination using various renewable energy sources to supply fresh water in remote, rural areas and on ships where other desalination processes are inefficient or unfeasible. For this strategic desalination application, MD is technically viable, but more works on configuration modification and process optimisation are required to reduce the process energy consumption and water production costs. For the three other strategic applications, the technical viability of the MD process has been proved by extensive lab-scale researches, but its economic feasibility is still questionable due to the lack of large-scale evaluation and the uncertain costs of MD systems. Summary: The orientation of MD towards strategic water treatment applications is clear. However, huge efforts are required to facilitate these applications at commercial and full scale.
Dwi Prasetyo, W, Putra, ZA, Bilad, MR, Mahlia, TMI, Wibisono, Y, Nordin, NAH & Wirzal, MDH 2020, 'Insight into the Sustainable Integration of Bio- and Petroleum Refineries for the Production of Fuels and Chemicals', Polymers, vol. 12, no. 5, pp. 1091-1091.
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A petroleum refinery heavily depends on crude oil as its main feedstock to produce liquid fuels and chemicals. In the long term, this unyielding dependency is threatened by the depletion of the crude oil reserve. However, in the short term, its price highly fluctuates due to various factors, such as regional and global security instability causing additional complexity on refinery production planning. The petroleum refining industries are also drawing criticism and pressure due to their direct and indirect impacts on the environment. The exhaust gas emission of automobiles apart from the industrial and power plant emission has been viewed as the cause of global warming. In this sense, there is a need for a feasible, sustainable, and environmentally friendly generation process of fuels and chemicals. The attention turns to the utilization of biomass as a potential feedstock to produce substitutes for petroleum-derived fuels and building blocks for biochemicals. Biomass is abundant and currently is still low in utilization. The biorefinery, a facility to convert biomass into biofuels and biochemicals, is still lacking in competitiveness to a petroleum refinery. An attractive solution that addresses both is by the integration of bio- and petroleum refineries. In this context, the right decision making in the process selection and technologies can lower the investment and operational costs and assure optimum yield. Process optimization based on mathematical programming has been extensively used to conduct techno-economic and sustainability analysis for bio-, petroleum, and the integration of both refineries. This paper provides insights into the context of crude oil and biomass as potential refinery feedstocks. The current optimization status of either bio- or petroleum refineries and their integration is reviewed with the focus on the methods to solve the multi-objective optimization problems. Internal and external uncertain parameters are importan...
Ekanayake, UGM, Seo, DH, Faershteyn, K, O'Mullane, AP, Shon, H, MacLeod, J, Golberg, D & Ostrikov, KK 2020, 'Atmospheric-pressure plasma seawater desalination: Clean energy, agriculture, and resource recovery nexus for a blue planet', Sustainable Materials and Technologies, vol. 25, pp. e00181-e00181.
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Fabris, M, Abbriano, RM, Pernice, M, Sutherland, DL, Commault, AS, Hall, CC, Labeeuw, L, McCauley, JI, Kuzhiuparambil, U, Ray, P, Kahlke, T & Ralph, PJ 2020, 'Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy', Frontiers in Plant Science, vol. 11.
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Mankind has recognized the value of land plants as renewable sources of food, medicine, and materials for millennia. Throughout human history, agricultural methods were continuously modified and improved to meet the changing needs of civilization. Today, our rapidly growing population requires further innovation to address the practical limitations and serious environmental concerns associated with current industrial and agricultural practices. Microalgae are a diverse group of unicellular photosynthetic organisms that are emerging as next-generation resources with the potential to address urgent industrial and agricultural demands. The extensive biological diversity of algae can be leveraged to produce a wealth of valuable bioproducts, either naturally or via genetic manipulation. Microalgae additionally possess a set of intrinsic advantages, such as low production costs, no requirement for arable land, and the capacity to grow rapidly in both large-scale outdoor systems and scalable, fully contained photobioreactors. Here, we review technical advancements, novel fields of application, and products in the field of algal biotechnology to illustrate how algae could present high-tech, low-cost, and environmentally friendly solutions to many current and future needs of our society. We discuss how emerging technologies such as synthetic biology, high-throughput phenomics, and the application of internet of things (IoT) automation to algal manufacturing technology can advance the understanding of algal biology and, ultimately, drive the establishment of an algal-based bioeconomy.
Fabris, M, George, J, Kuzhiumparambil, U, Lawson, CA, Jaramillo-Madrid, AC, Abbriano, RM, Vickers, CE & Ralph, P 2020, 'Extrachromosomal Genetic Engineering of the Marine Diatom Phaeodactylum tricornutum Enables the Heterologous Production of Monoterpenoids', ACS Synthetic Biology, vol. 9, no. 3, pp. 598-612.
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Geraniol is a commercially relevant plant-derived monoterpenoid that is a main component of rose essential oil and used as insect repellent. Geraniol is also a key intermediate compound in the biosynthesis of the monoterpenoid indole alkaloids (MIAs), a group of over 2000 compounds that include high-value pharmaceuticals. As plants naturally produce extremely small amounts of these molecules and their chemical synthesis is complex, industrially sourcing these compounds is costly and inefficient. Hence, microbial hosts suitable to produce MIA precursors through synthetic biology and metabolic engineering are currently being sought. Here, we evaluated the suitability of a eukaryotic microalga, the marine diatom Phaeodactylum tricornutum, for the heterologous production of monoterpenoids. Profiling of endogenous metabolism revealed that P. tricornutum, unlike other microbes employed for industrial production of terpenoids, accumulates free pools of the precursor geranyl diphosphate. To evaluate the potential for larger synthetic biology applications, we engineered P. tricornutum through extrachromosomal, episome-based expression, for the heterologous biosynthesis of the MIA intermediate geraniol. By profiling the production of geraniol resulting from various genetic and cultivation arrangements, P. tricornutum reached the maximum geraniol titer of 0.309 mg/L in phototrophic conditions. This work provides (i) a detailed analysis of P. tricornutum endogenous terpenoid metabolism, (ii) a successful demonstration of extrachromosomal expression for metabolic pathway engineering with potential gene-stacking applications, and (iii) a convincing proof-of-concept of the suitability of P. tricornutum as a novel production platform for heterologous monoterpenoids, with potential for complex pathway engineering aimed at the heterologous production of MIAs.
Faisal, M, Hannan, MA, Ker, PJ, Rahman, MSA, Begum, RA & Mahlia, TMI 2020, 'Particle swarm optimised fuzzy controller for charging–discharging and scheduling of battery energy storage system in MG applications', Energy Reports, vol. 6, pp. 215-228.
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© 2020 The Authors Aiming at reducing the power consumption and costs of grids, this paper deals with the development of particle swarm optimisation (PSO) based fuzzy logic controller (FLC) for charging–discharging and scheduling of the battery energy storage systems (ESSs) in microgrid (MG) applications. Initially, FLC was developed to control the charging–discharging of the storage system to avoid mathematical calculation of the conventional system. However, to improve the charging–discharging control, the membership function of the FLC is optimised using PSO technique considering the available power, load demand, battery temperature and state of charge (SOC). The scheduling controller is the optimal solution to achieve low-cost uninterrupted reliable power according to the loads. To reduce the grid power demand and consumption costs, an optimal binary PSO is also introduced to schedule the ESS, grid and distributed sources under various load conditions at different times of the day. The obtained results proved that the robustness of the developed PSO based fuzzy control can effectively manage the battery charging–discharging with reducing the significant grid power consumption of 42.26% and the costs of the energy usage by 45.11% which also demonstrates the contribution of the research.
Fang, C, Rajabzadeh, S, Zhang, P, Liu, W, Kato, N, Shon, HK & Matsuyama, H 2020, 'Controlling spherulitic structures at surface and sub-layer of hollow fiber membranes prepared using nucleation agents via triple-orifice spinneret in TIPS process', Journal of Membrane Science, vol. 609, pp. 118229-118229.
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Fatahi, B, Huang, B, Yeganeh, N, Terzaghi, S & Banerjee, S 2020, 'Three-Dimensional Simulation of Seismic Slope–Foundation–Structure Interaction for Buildings Near Shallow Slopes', International Journal of Geomechanics, vol. 20, no. 1, pp. 04019140-04019140.
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© 2019 American Society of Civil Engineers. Buildings constructed adjacent to the slope crest in seismically active areas might be exposed to serious danger when they are subjected to strong earthquake excitations. The ground conditions can influence the seismic response of structures through a phenomenon known as the slope-foundation-structure interaction. Indeed, the presence of the slope in the vicinity of a building foundation can significantly affect the seismic response of the superstructure. In this study, the impact of shallow slopes on the seismic performance of nearby buildings was numerically assessed. In the adopted three-dimensional finite-element simulation, the nonlinear variations of the soil stiffness and damping with the cyclic shear strain plus varying distances between the edge of the foundation and crest of the slope were employed. A 15-story moment-resisting structure, a 30-m-thick clayey deposit, and a 2-m-high shallow slope were considered as the benchmark model, being simulated using the direct method in the time domain. According to the results of the analyses, the seismic response of a building could be highly sensitive to the distance between the slope crest and foundation. Particularly, the building closer to the slope crest experienced more severe foundation rocking, lateral deformation, and interstory drifts owing to the amplified effect of the slope-foundation-structure interaction. Moreover, the results highlighted the importance of the slope-foundation-structure interaction in altering the natural period and damping of the system. Hence, it is critical for practicing engineers to assess the impact of nearby slopes on the seismic performance of structures with extreme care to ensure the reliability and safety of the design.
Fattah, IMR, Noraini, MY, Mofijur, M, Silitonga, AS, Badruddin, IA, Khan, TMY, Ong, HC & Mahlia, TMI 2020, 'Lipid Extraction Maximization and Enzymatic Synthesis of Biodiesel from Microalgae', Applied Sciences, vol. 10, no. 17, pp. 6103-6103.
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Microalgae has received overwhelming attention worldwide as a sustainable source for energy generation. However, the production of biofuel from microalgae biomass consists of several steps, of which lipid extraction is the most important one. Because of the nature of feedstock, extraction needs special attention. Three different methods were studied to extract algal oil from two different algae variant, Chlorella sp. and Spirulina sp. The highest percentage oil yield was obtained by ultrasonication (9.4% for Chlorella sp., 6.6% for Spirulina sp.) followed by the Soxhlet and solvent extraction processes. Ultrasonication and Soxhlet extraction processes were further optimized to maximize oil extraction as solvent extraction was not effective in extracting lipid. For ultrasonication, an amplitude of 90% recorded the highest percentage yield of oil for Spirulina sp. and a 70% amplitude recorded the highest percentage yield of oil for Chlorella sp. On the other hand, for Soxhlet extraction, a combination of chloroform, hexane, and methanol at a 1:1:1 ratio resulted in the highest yield of algal oil. Afterward, the crude algae oil from the ultrasonication process was transesterified for 5 h using an immobilized lipase (Novozyme 435) at 40 °C to convert triglycerides into fatty acid methyl ester and glycerol. Thus, ultrasonic-assisted lipid extraction was successful in producing biodiesel from both the species.
Fisher, NL, Campbell, DA, Hughes, DJ, Kuzhiumparambil, U, Halsey, KH, Ralph, PJ & Suggett, DJ 2020, 'Divergence of photosynthetic strategies amongst marine diatoms', PLOS ONE, vol. 15, no. 12, pp. e0244252-e0244252.
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Marine phytoplankton, and in particular diatoms, are responsible for almost half of all primary production on Earth. Diatom species thrive from polar to tropical waters and across light environments that are highly complex to relatively benign, and so have evolved highly divergent strategies for regulating light capture and utilization. It is increasingly well established that diatoms have achieved such successful ecosystem dominance by regulating excitation energy available for generating photosynthetic energy via highly flexible light harvesting strategies. However, how different light harvesting strategies and downstream pathways for oxygen production and consumption interact to balance excitation pressure remains unknown. We therefore examined the responses of three diatom taxa adapted to inherently different light climates (estuarine Thalassioisira weissflogii, coastal Thalassiosira pseudonana and oceanic Thalassiosira oceanica) during transient shifts from a moderate to high growth irradiance (85 to 1200 μmol photons m-2 s-1). Transient high light exposure caused T. weissflogii to rapidly downregulate PSII with substantial nonphotochemical quenching, protecting PSII from inactivation or damage, and obviating the need for induction of O2 consuming (light-dependent respiration, LDR) pathways. In contrast, T. oceanica retained high excitation pressure on PSII, but with little change in RCII photochemical turnover, thereby requiring moderate repair activity and greater reliance on LDR. T. pseudonana exhibited an intermediate response compared to the other two diatom species, exhibiting some downregulation and inactivation of PSII, but high rep...
Gao, KW, Loo, WS, Snyder, RL, Abel, BA, Choo, Y, Lee, A, Teixeira, SCM, Garetz, BA, Coates, GW & Balsara, NP 2020, 'Miscible Polyether/Poly(ether–acetal) Electrolyte Blends', Macromolecules, vol. 53, no. 14, pp. 5728-5739.
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George, J, Kahlke, T, Abbriano, RM, Kuzhiumparambil, U, Ralph, PJ & Fabris, M 2020, 'Metabolic Engineering Strategies in Diatoms Reveal Unique Phenotypes and Genetic Configurations With Implications for Algal Genetics and Synthetic Biology', Frontiers in Bioengineering and Biotechnology, vol. 8.
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Ghobadi, R, Altaee, A, Zhou, JL, McLean, P & Yadav, S 2020, 'Copper removal from contaminated soil through electrokinetic process with reactive filter media', Chemosphere, vol. 252, pp. 126607-126607.
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Gomes, SDC, Zhou, JL, Li, W & Qu, F 2020, 'Recycling of raw water treatment sludge in cementitious composites: effects on heat evolution, compressive strength and microstructure', Resources, Conservation and Recycling, vol. 161, pp. 104970-104970.
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Water treatment sludge (WTS) is produced daily and represents a globally significant solid waste stream. The application of this sludge as construction materials has been studied although most studies have modified the sludge before its incorporation, hence involving significant energy consumption. This study aims to use raw sludge as a novel cementitious material, by determining the effects of sludge addition on the composition and performance of cementitious composites. Important aspects such as the physicochemical interaction of the raw sludge with the Portland cement, the heat evolution of the cement paste and the compressive strength of the composite cement were carefully studied. The results show that for 1-2% of WTS addition, the compressive strength and heat evolution of the cement paste was well maintained being close to the reference specimen after 28 days of curing. However, for sludge addition above 5%, a delay in the hydration reaction was observed, together with about 25% reduction in compressive strength at 28 days of curing. The mineralogical and thermal analysis showed decreasing portlandite content and increasing calcite in the WTS-amended composites. Scanning electron microscope analysis demonstrated that the addition of sludge induced more porous and weak surface structures compared to the reference specimen.
Gonzales, RR, Yang, Y, Park, MJ, Bae, T-H, Abdel-Wahab, A, Phuntsho, S & Shon, HK 2020, 'Enhanced water permeability and osmotic power generation with sulfonate-functionalized porous polymer-incorporated thin film nanocomposite membranes', Desalination, vol. 496, pp. 114756-114756.
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Gowri, AK, Karunakaran, MJ, Muthunarayanan, V, Ravindran, B, Nguyen-Tri, P, Ngo, HH, Bui, X-T, Nguyen, XH, Nguyen, DD, Chang, SW & Chandran, T 2020, 'Evaluation of bioremediation competence of indigenous bacterial strains isolated from fabric dyeing effluent', Bioresource Technology Reports, vol. 11, pp. 100536-100536.
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© 2020 Elsevier Ltd In this present assessment, fabric dyeing wastewater was subjected to the characterization of physical-chemical parameters in terms of colour, TDS, COD and chloride. The indigenous bacterial strains were isolated from the effluent and identified as Bacillus velezensis, Chryseomicrobium imtechense, Planococcus maritimus and Sphingobacterium daejeonense by 16S rRNA gene sequencing method. The bioremediation competency of the strains was evaluated by conducting treatment process with monoculture and bacterial consortium. The consortia removed about 98%, 71.5%, 79%, 69.65% of colour, TDS, COD and chloride, respectively. Among the four isolates, monoculture of B. velezensis showed effective diminution of pollutants from the effluent than other strains. The bacterial degradation of pollutants was determined by GC–MS based on the disappearance of certain peaks after bioremediation. The results suggested that the bioremediation efficiency of bacterial strains can be utilized as an eco-friendly and inexpensive method for dyeing effluent treatment.
Gul, M, Kalam, MA, Mujtaba, MA, Alam, S, Bashir, MN, Javed, I, Aziz, U, Farid, MR, Hassan, MT & Iqbal, S 2020, 'Multi-objective-optimization of process parameters of industrial-gas-turbine fueled with natural gas by using Grey-Taguchi and ANN methods for better performance', Energy Reports, vol. 6, pp. 2394-2402.
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Gul, M, Masjuki, HH, Kalam, MA, Zulkifli, NWM & Mujtaba, MA 2020, 'A Review: Role of Fatty Acids Composition in Characterizing Potential Feedstock for Sustainable Green Lubricants by Advance Transesterification Process and its Global as Well as Pakistani Prospective', BioEnergy Research, vol. 13, no. 1, pp. 1-22.
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High demand for crop oils is anticipated in the lubricant industry because of their renewable, non-toxic, environment-friendly nature. Crop oils typically offer high viscosities, viscosity indexes, and flashpoints. The unique structure of crop oils provides good lubrication, high flammability, and anti-corrosion ability. In contrast, petroleum-based lubricants face a difficult future because of declining petroleum reservoirs that will increase their prices. This paper reviews green-lubricant feedstock requirements, the effect of fatty acids composition to improve physicochemical properties, chemical modifications of green lubricants by applying transesterification to find suitable environmentally -friendly and cheaper feedstock to replace petroleum lubricants. Moreover, global and Pakistani indigenous crop oils are also analyzed for their potential use in green lubricants by comparing their fatty acid compositions, characteristics and reaction conditions according to applications and standards. This review discovers that cottonseed oil has great potential as a new sustainable and cheaper feedstock for the global and Pakistani green-lubricant markets. Green lubricant production rate can be enhanced significantly after upgrading the conventional production method. It is believed that this review paper will provide useful information to engineers, researchers, chemists, industrialists, and policymakers, who are interested in green-lubricants synthesis.
Gul, M, Zulkifli, NWM, Masjuki, HH, Kalam, MA, Mujtaba, MA, Harith, MH, Syahir, AZ, Ahmed, W & Bari Farooq, A 2020, 'Effect of TMP-based-cottonseed oil-biolubricant blends on tribological behavior of cylinder liner-piston ring combinations', Fuel, vol. 278, pp. 118242-118242.
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Cottonseed oil-based biolubricant was synthesized by the TMP-based transesterification process. 10–50% by volume blends of TMP-based cotton-biolubricant and SAE-40 were prepared and tested on the high-frequency-reciprocating-rig with engine cylinder-liner and piston-ring combination to investigate their tribology. While tribological characteristics were also evaluated by four-ball tribo-testers at high constant load of 785 N. 10% addition of cotton-biolubricant showed the lowest friction and wear as compared to SAE-40 but>10% volume of cotton biolubricant in blend increased the wear and friction considerably as tested by both HFRR and four-ball. Hence, 10% addition of TMP-cotton-biolubricant can be utilized as an energy-saving lubricant additive to partially reduce the dependency on petroleum-based lubricant for automotive engine application.
Guo, W, Nguyen, PD, You, S-J & Lin, C 2020, 'Editorial - Special issue on green technologies for waste treatment', Bioresource Technology Reports, vol. 11, pp. 100495-100495.
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Guo, Y, Karimi, F, Fu, Q, G. Qiao, G & Zhang, H 2020, 'Reduced administration frequency for the treatment of fungal keratitis: a sustained natamycin release from a micellar solution', Expert Opinion on Drug Delivery, vol. 17, no. 3, pp. 407-421.
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Background: Natamycin is the only topical ophthalmic antifungal drug approved by the Food and Drug Administration (FDA) of the United States, but has unsatisfactory factors such as high dosing frequency.Methods: We report the synthesis and preparation of self-assembled poly(ethylene glycol)-block-poly(glycidyl methacrylate) (PEG-b-PGMA) micelles. These nanoparticles exhibit sustained delivery of a hydrophobic natamycin by topical administration on eye due to the hydrolysable properties of PGMA segments of micelle. Hydrolysis of glycidyl groups within a physiologically relevant environment provides an additional driving force for drug release by generation of hydrophilic hydroxyl groups to 'push' the encapsulated hydrophobic drug away from the resultant hydrophilic domains and into surrounding environment.Results: In vitro and in vivo results revealed that the self-assembled micelles and the encapsulated natamycin were not cytotoxic and the released drug have strong antifungal ability to Candida albicans. Importantly, sustained natamycin release from micelles leads to the reduced administration frequency of natamycin from 8 times per day to 3 times per day in rabbits suffering from fungal keratitis (FK).Conclusion: This study demonstrates a facile method that can greatly reduce dosing frequency of natamycin administration and thus improve long-term patient compliance.
Guo, Z, Kang, Y, Hu, Z, Liang, S, Xie, H, Ngo, HH & Zhang, J 2020, 'Removal pathways of benzofluoranthene in a constructed wetland amended with metallic ions embedded carbon', Bioresource Technology, vol. 311, pp. 123481-123481.
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Hafiz, M, Hawari, AH, Yasir, AT, Alfahel, R, Hassan, MK & Altaee, A 2020, 'Impact of high turbidity on reverse osmosis: evaluation of pretreatment processes', DESALINATION AND WATER TREATMENT, vol. 208, pp. 96-103.
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This study evaluates the performance of sand filtration (SF) and ultra-filtration (UF) as pretreatment processes for reverse osmosis (RO) for seawater with turbidities of 4.8, 23.2, and 99.7 NTU. For seawater with a turbidity of 4.8 and 23.2 NTU, the average membrane flux and the water recovery rate in the RO process did not improve significantly by pretreating the seawater using SF or UF. However, when the turbidity of seawater was 99.7 NTU, pretreating the seawater with UF improved the average membrane flux and the water recovery rate in the RO process by 5 LMH and 1.7%, respectively. Pretreatment of seawater with a turbidity of 99.7 NTU with UF reduces the specific energy demand and increases the average membrane flux and water recovery rate.
Han, R, Liu, F, Wang, X, Huang, M, Li, W, Yamauchi, Y, Sun, X & Huang, Z 2020, 'Functionalised hexagonal boron nitride for energy conversion and storage', Journal of Materials Chemistry A, vol. 8, no. 29, pp. 14384-14399.
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This review highlights recent research advances in functionalised hexagonal boron nitride for energy conversion and storage applications.
Hannan, MA, Ali, JA, Hossain Lipu, MS, Mohamed, A, Ker, PJ, Indra Mahlia, TM, Mansor, M, Hussain, A, Muttaqi, KM & Dong, ZY 2020, 'Role of optimization algorithms based fuzzy controller in achieving induction motor performance enhancement', Nature Communications, vol. 11, no. 1, p. 3792.
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AbstractThree-phase induction motors (TIMs) are widely used for machines in industrial operations. As an accurate and robust controller, fuzzy logic controller (FLC) is crucial in designing TIMs control systems. The performance of FLC highly depends on the membership function (MF) variables, which are evaluated by heuristic approaches, leading to a high processing time. To address these issues, optimisation algorithms for TIMs have received increasing interest among researchers and industrialists. Here, we present an advanced and efficient quantum-inspired lightning search algorithm (QLSA) to avoid exhaustive conventional heuristic procedures when obtaining MFs. The accuracy of the QLSA based FLC (QLSAF) speed control is superior to other controllers in terms of transient response, damping capability and minimisation of statistical errors under diverse speeds and loads. The performance of the proposed QLSAF speed controller is validated through experiments. Test results under different conditions show consistent speed responses and stator currents with the simulation results.
Hannan, MA, Begum, RA, Al-Shetwi, AQ, Ker, PJ, Al Mamun, MA, Hussain, A, Basri, H & Mahlia, TMI 2020, 'Waste collection route optimisation model for linking cost saving and emission reduction to achieve sustainable development goals', Sustainable Cities and Society, vol. 62, pp. 102393-102393.
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© 2020 Elsevier Ltd Developing an efficient, cost-effective and environmentally friendly solution for solid waste collection (SWC) and transportation system remains a major challenge for municipalities. Waste collection encompasses the largest part of the total budget in current waste management systems. SWC is a crosscutting issue that can be directly or indirectly linked to 10 of the 17 United Nations’ sustainable development goals (SDGs). This study aims to develop an SWC route optimisation model to improve collection efficiency, save collection costs and reduce emissions by considering fixed routing optimisation (FRO) with static data and variable routing optimisation (VRO) with real-time data. To realise the optimisation, a mixed-integer linear programming model utilising FRO and VRO was developed. Results show that VRO improved the collection efficiency by 26.08 % when the minimum filled-up level for collection was 70 %. Moreover, VRO achieved 44.44 % cost savings and 17.60 % carbon emission reduction at 70 % filled level. The proposed system achieved the targeted goals and demonstrated the feasibility of an optimisation model for the waste management sector to build a sustainable smart city. The findings of this study can be used to strengthen efforts towards the achievement of the SDGs related to solid waste collection and management.
Hannan, MA, Lipu, MSH, Hussain, A, Ker, PJ, Mahlia, TMI, Mansor, M, Ayob, A, Saad, MH & Dong, ZY 2020, 'Toward Enhanced State of Charge Estimation of Lithium-ion Batteries Using Optimized Machine Learning Techniques', Scientific Reports, vol. 10, no. 1, p. 4687.
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AbstractState of charge (SOC) is a crucial index used in the assessment of electric vehicle (EV) battery storage systems. Thus, SOC estimation of lithium-ion batteries has been widely investigated because of their fast charging, long-life cycle, and high energy density characteristics. However, precise SOC assessment of lithium-ion batteries remains challenging because of their varying characteristics under different working environments. Machine learning techniques have been widely used to design an advanced SOC estimation method without the information of battery chemical reactions, battery models, internal properties, and additional filters. Here, the capacity of optimized machine learning techniques are presented toward enhanced SOC estimation in terms of learning capability, accuracy, generalization performance, and convergence speed. We validate the proposed method through lithium-ion battery experiments, EV drive cycles, temperature, noise, and aging effects. We show that the proposed method outperforms several state-of-the-art approaches in terms of accuracy, adaptability, and robustness under diverse operating conditions.
Hao Ngo, H, Bui, X-T, Nghiem, LD & Guo, W 2020, 'Green technologies for sustainable water', Bioresource Technology, vol. 317, pp. 123978-123978.
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Hao, D, Liu, C, Xu, X, Kianinia, M, Aharonovich, I, Bai, X, Liu, X, Chen, Z, Wei, W, Jia, G & Ni, B-J 2020, 'Surface defect-abundant one-dimensional graphitic carbon nitride nanorods boost photocatalytic nitrogen fixation', New Journal of Chemistry, vol. 44, no. 47, pp. 20651-20658.
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Defective g-C3N4 nanorods enable to boots the adsorption and cleavage of N2 molecules to achieve higher photocatalytic nitrogen fixation performance.
Hao, Q, Jia, G, Wei, W, Vinu, A, Wang, Y, Arandiyan, H & Ni, B-J 2020, 'Graphitic carbon nitride with different dimensionalities for energy and environmental applications', Nano Research, vol. 13, no. 1, pp. 18-37.
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© 2019, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature. As a metal-free semiconductor, graphitic carbon nitride (g-C3N4) has received extensive attention due to its high stability, nontoxicity, facile and low-cost synthesis, appropriate band gap in the visible spectral range and wide availability of resources. The dimensions of g-C3N4 can influence the regime of the confinement of electrons, and consequently, g-C3N4 with various dimensionalities shows different properties, making them available for many stimulating applications. Although there are some reviews focusing on the synthesis strategy and applications of g-C3N4, there is still a lack of comprehensive review that systemically summarises the synthesis and application of different dimensions of g-C3N4, which can provide an important theoretical and practical basis for the development of g-C3N4 with different dimensionalities and maximises their potential in diverse applications. By reviewing the latest progress of g-C3N4 studies, we aim to summarise the preparation of g-C3N4 with different dimensionalities using various structural engineering strategies, discuss the fundamental bottlenecks of currently existing methods and their solution strategies, and explore their applications in energy and environmental applications. Furthermore, it also puts forward the views on the future research direction of these unique materials. [Figure not available: see fulltext.]
Hao, Q, Liu, C, Jia, G, Wang, Y, Arandiyan, H, Wei, W & Ni, B-J 2020, 'Catalytic reduction of nitrogen to produce ammonia by bismuth-based catalysts: state of the art and future prospects', Materials Horizons, vol. 7, no. 4, pp. 1014-1029.
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This review provides an up-to-date review on Bi-based nitrogen-fixation materials and future directions for the development of new Bi-based nitrogen-fixation materials under ambient conditions.
Hao, Q, Xie, C, Huang, Y, Chen, D, Liu, Y, Wei, W & Ni, B-J 2020, 'Accelerated separation of photogenerated charge carriers and enhanced photocatalytic performance of g-C3N4 by Bi2S3 nanoparticles', Chinese Journal of Catalysis, vol. 41, no. 2, pp. 249-258.
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© 2020 Dalian Institute of Chemical Physics, the Chinese Academy of Sciences Employing photothermal conversion to improve the photocatalytic activity of g-C3N4 is rarely reported previously. Herein, different ratios of g-C3N4/Bi2S3 heterojunction materials are synthesized by a facile ultrasonic method. Advanced characterizations such as X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy are employed to analyze the morphology and structure of the prepared materials. Compared with sole counterparts, the heterojunction materials CN-BiS-2 exhibit significantly enhanced photocatalytic performance, which is 2.05-fold as g-C3N4 and 4.42-fold as Bi2S3. A possible degradation pathway of methylene blue (MB) was proposed. Based on the photoproduced high-energy electrons and photothermal effect of Bi2S3, the transfer and separation of electron-hole pairs are greatly enhanced and more active species are produced. In addition, the relatively high utilization efficiency of solar energy has synergistic effect for the better photocatalytic performance.
Hawari, AH, Hafiz, M, Yasir, AT, Alfahel, R & Altaee, A 2020, 'Evaluation of ultrafiltration and multimedia filtration as pretreatment process for forward osmosis', DESALINATION AND WATER TREATMENT, vol. 195, pp. 84-92.
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© 2020 Desalination Publications. All rights reserved. In order to reduce scaling in a multistage flash (MSF) desalination plant, the brine reject can be diluted using forward osmosis (FO) before recycling. In this FO process, the brine is used as the draw solution (DS) and seawater is used as the feed solution (FS). However, the FO process suffers from low water flux owing to membrane fouling. The water flux in FO can be enhanced by reduc-ing the foulant concentration in the FO feed solution (FS). Thus, in this paper seawater, multimedia sand filtered seawater, and ultrafiltrated seawater is being used as feed solution for the FO process. The flowrate of the feed solution was kept constant at 2.0 L/min. However, the flowrate of the draw solution (DS) were tested at 2.0 and 0.8 L/min. When the flowrate of the DS was 0.8 L/min, the highest initial flux of 44.1 L/m2 h were obtained using ultrafiltrated seawater as FS. After the initial run, the membrane was cleaned and during the second run, 83% of the initial flux was recovered using the ultrafiltrated seawater as FS. For ultrafiltrated seawater, the water recovery rate and specific energy consumption was 36.2% and 0.065 kWh/m3, respectively.
Hazrat, MA, Rasul, MG, Mofijur, M, Khan, MMK, Djavanroodi, F, Azad, AK, Bhuiya, MMK & Silitonga, AS 2020, 'A Mini Review on the Cold Flow Properties of Biodiesel and its Blends', Frontiers in Energy Research, vol. 8, p. 598651.
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Biodiesels are renewable fuel that may be produced from various feedstock using different techniques. It is endorsed in some countries of the world as a viable substitute to diesel fuel. While biodiesel possesses numerous benefits, the cold flow properties (CFP) of biodiesel in comparison with petro-diesel are significantly less satisfactory. This is due to the presence of saturated and unsaturated fatty acid esters. The poor CFP of biodiesel subsequently affects performance in cold weather and damages the engine fuel system, as well as chokes the fuel filter, fuel inlet lines, and injector nozzle. Previously, attempts were made to minimize the damaging impact of bad cold flow through the reduction of pour point, cloud point, and the cold filter plugging point of biodiesel. This study is focused on the biodiesel CFP-related mechanisms and highlights the factors that initialize and pace the crystallization process. This review indicates that the CFP of biodiesel fuel can be improved by utilizing different techniques. Winterisation of some biodiesel has been shown to improve CFP significantly. Additives such as polymethyl acrylate improved CFP by 3-9 ° C. However, it is recommended that improvement methods in terms of fuel properties and efficiency should be carefully studied and tested before being implemented in industrial applications as this might impact biodiesel yield, cetane number, etc.
Helwani, Z, Ramli, M, Rusyana, A, Marlina, M, Fatra, W, Idroes, GM, Suhendra, R, Ashwie, V, Mahlia, TMI & Idroes, R 2020, 'Alternative Briquette Material Made from Palm Stem Biomass Mediated by Glycerol Crude of Biodiesel Byproducts as a Natural Adhesive', Processes, vol. 8, no. 7, pp. 777-777.
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Recently, the global population has increased sharply, unfortunately, the availability of fossil fuel resources has significantly decreased. This phenomenon has become an attractive issue for many researchers in the world so that various studies in the context of finding renewable energy are developing continuously. Relating to this challenge, this research has been part of scientific work in the context of preparing an energy briquette employing palm oil stems and glycerol crude of biodiesel byproducts as inexpensive and green materials easily found in the Riau province, Indonesia. Technically, the palm oil stems are used for the production of charcoal particles and the glycerol crude as an adhesive compound in the production of energy briquettes. The heating value of palm oil stem is 17,180 kJ/kg, which can be increased to an even higher value through a carbonization process followed by a densification process so that it can be used as a potential matrix to produce energy briquettes. In detail, this study was designed to find out several parameters including the effect of sieve sizes consisting of 60, 80, and 100 mesh, respectively, which are used for the preparation of charcoal particles as the main matrix for the manufacture of the briquettes; the effect of charcoal-adhesive ratios (wt) of 60:40, 70:30, and 80:20; and the effect of varied pressures of 100, 110, and 120 kg/cm2 on the briquette quality. The quality of the obtained briquettes is analyzed through the observation of important properties which involve the heating value and the compressive strength using Response Surface Methodology (RSM). The results showed that the produced briquettes had an optimum heating value of 30,670 kJ/kg, while their loaded charcoal particles resulted from the mesh sieve of 80, in which there was a charcoal loading of 53 g and it pressed at 93.1821 bar, whereas, the compressive strength value of the briquette was 100,608 kg/cm2, which loaded charcoal part...
Helwani, Z, Ramli, M, Saputra, E, Bahruddin, B, Yolanda, D, Fatra, W, Idroes, GM, Muslem, M, Mahlia, TMI & Idroes, R 2020, 'Impregnation of CaO from Eggshell Waste with Magnetite as a Solid Catalyst (Fe3O4/CaO) for Transesterification of Palm Oil Off-Grade', Catalysts, vol. 10, no. 2, pp. 164-164.
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In this work, calcium oxide (CaO) extracted from eggshell impregnated with magnetite (Fe3O4) is prepared successfully and it had been applied on transesterification of palm oil off-grade. Prior experiment, the eggshells material are powdered and calcined at 900 °C then impregnated with Fe3O4 and recalcined. The obtained Fe3O4/CaO catalyst is characterized using X-ray diffraction and Braunaeur–Emmet–Teller (BET) surface area. The influence of various parameters including recalcined time and temperature are investigated. The prepared catalyst is tested for transesterification of palm oil off-grade to produce biodiesel in which the optimal conditions of a methanol/palm oil off-grade molar ratio of 10:1, the catalyst weight of 6%, the reaction temperature of 70 °C, and the reaction time of 2 h. The transesterification product was analyzed using GC-MS, which showed the biodiesel yield of 90% at the recalcined temperature of 600 °C and reaction time of 2 h. It has been noted that the catalyst activity is achieved when the moderate recalcination temperature is applied and the disordered structure of the catalyst is maintained. This study also confirms that CaO impregnated with Fe3O4 could be a solid catalyst for the biodiesel synthesis through transesterification reaction of palm oil off-grade.
Hien, NT, Nguyen, LH, Van, HT, Nguyen, TD, Nguyen, THV, Chu, THH, Nguyen, TV, Trinh, VT, Vu, XH & Aziz, KHH 2020, 'Heterogeneous catalyst ozonation of Direct Black 22 from aqueous solution in the presence of metal slags originating from industrial solid wastes', Separation and Purification Technology, vol. 233, pp. 115961-115961.
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© 2019 Elsevier B.V. This study developed a low cost catalyst, namely, zinc slag (Zn-S) for the ozonation process of Direct Black 22 (DB22) from aqueous solutions. Among five different kind of low cost metal slags including Fe-S, Cu-S, Cd-S, Pb-S and Zn-S, the Zn-S slag was selected as an efficient catalyst in this study. Zn-S contained mainly zinc (Zn) and calcium (Ca) discharged from zinc slag waste in Vietnam. It was found that Zn-S could effectively decolonize and mineralize DB22 through heterogeneous catalytic ozonation. The degradation kinetic of DB22 followed the pseudo-first order model. The best removal efficiency of DB22 (Zn-S/O3/H2O2 (76%) > Zn-S/O3 (69%) > O3/H2O2 (66%) > O3 (55% for COD) occurred at pH 11 for heterogeneous catalytic ozonation processes with Zn-S as the catalyst as well as ozone alone and perozone processes due to fast decomposition of O3 in alkaline solution to generate powerful and non-selective OH radicals. An increase in decolonization and mineralization rate was observed when increasing the Zn-S dosage from 0.125 g/L to 0.75 g/L for Zn-S/O3 and 0.125 g/L to 1.0 g/L for Zn-S/O3/H2O2. The K values of the pseudo-first order model followed the same sequence as mineralization rates of DB22 in term of COD removal. Ca and Zn constituents in the Zn-S catalyst contributed to the increase in O3 decomposition and improvement of reaction rate with H2O2. Subsequently, the degradation of DB22 by the ozonation process with Zn-S catalyst was enhanced through the enrichment mechanism of hydroxyl radicals (*OH) and surface adsorption. The degradation mechanism of DB22 by hydroxyl radicals was surely affirmed by tests with the decrease in degradation percentage of DB22 in case of the presence t-butanol, Cl− and CO32−.
Hirsimaki, C, Outram, JG, Millar, GJ & Altaee, A 2020, 'Process simulation of high pH reverse osmosis systems to facilitate reuse of coal seam gas associated water', Journal of Environmental Chemical Engineering, vol. 8, no. 5, pp. 104122-104122.
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Hoang, LP, Nguyen, TMP, Van, HT, Hoang, TKD, Vu, XH, Nguyen, TV & Ca, NX 2020, 'Cr(VI) Removal from Aqueous Solution Using a Magnetite Snail Shell', Water, Air, & Soil Pollution, vol. 231, no. 1.
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© 2020, Springer Nature Switzerland AG. In this study, magnetic snail shell (MSS) prepared by impregnating of iron oxide onto snail shell (SS) powder was used for removing Cr(VI) from aqueous solution. Among six different mass ratios of Fe/SS powder studied, the MSS25 produced at a ratio of 25% achieved the highest Cr(VI) adsorption capacity. Batch adsorption experiments were conducted to investigate the adsorption isotherm, kinetics, and mechanism of Cr(VI) onto MSS25. The results illustrated that adsorption of Cr(VI) onto MSS25 reached equilibrium after 150 min at pH 3. The adsorption kinetics could be well described by the pseudo-second order model (R2 = 0.986). The Langmuir model (R2 = 0.971) was the best-fitting model that described the adsorption isotherm of Cr(VI) onto MSS25. The maximum adsorption capacity was 46.08 mg Cr(VI) per gram of MSS25. Ion exchange, electrostatic attraction, and adsorption-coupled reduction were determined as the main adsorption mechanisms of Cr(VI) onto MSS25. The high percentages of CaCO3 and Fe3O4 found in the MSS25 structure made a significant contribution to the Cr(VI) adsorption process.
Hossain, N, Hasan, MH, Mahlia, TMI, Shamsuddin, AH & Silitonga, AS 2020, 'Feasibility of microalgae as feedstock for alternative fuel in Malaysia: A review', Energy Strategy Reviews, vol. 32, pp. 100536-100536.
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© 2020 The Authors Biodiesel is an attractive fuel replacement for diesel engine in Malaysia. The application of biodiesel as fuel-blend has been implemented commercially in transport sector in the country. Among various potential feedstock for biodiesel production, microalgae have been appeared as a promising source since a decade due to its' high biomass productivity, rapid growth rate, large amount of lipid content, capability of high CO2 capture and sequestration as well as suitable geographical location to be harvested. The main objective of this study was to determine the feasibility of microalgae harvesting in Malaysia to produce biodiesel and potential to implement microalgae-biodiesel as commercial transportation fuel. This study demonstrated the current scenario of overall biodiesel production and application in Malaysia. Since Malaysia is the world's second-largest oil palm producer, exploitation of edible palm oil for the making of biodiesel is to be blamed as the cause of soaring food price; therefore, the country is currently looking for 3rd generation biofuel sources and microalgae has been preferred for this purpose. Therefore, insight of the significance of microalgae cultivation for this purpose, suitable microalgae candidates and possible feasibility of microalgae biodiesel have been delineated in this review study. Prospects and challenges to implement microalgae biodiesel have also been emphasized in this study. Therefore, the advantages and limitations of this biodiesel can be transparent to government and non-government sectors. Thus, this study can re-direct both sectors in future. Consequently, it may contribute setting an appropriate government policy to encourage microalgae for biodiesel production to sustain the local biofuel and secure economic growth, energy security and improve environmental conditions in near future.
Hossain, N, Nizamuddin, S, Griffin, G, Selvakannan, P, Mubarak, NM & Mahlia, TMI 2020, 'Synthesis and characterization of rice husk biochar via hydrothermal carbonization for wastewater treatment and biofuel production', Scientific Reports, vol. 10, no. 1, p. 18851.
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AbstractThe recent implication of circular economy in Australia spurred the demand for waste material utilization for value-added product generations on a commercial scale. Therefore, this experimental study emphasized on agricultural waste biomass, rice husk (RH) as potential feedstock to produce valuable products. Rice husk biochar (RB) was obtained at temperature: 180 °C, pressure: 70 bar, reaction time: 20 min with water via hydrothermal carbonization (HTC), and the obtained biochar yield was 57.9%. Enhancement of zeta potential value from − 30.1 to − 10.6 mV in RB presented the higher suspension stability, and improvement of surface area and porosity in RB demonstrated the wastewater adsorption capacity. Along with that, an increase of crystallinity in RB, 60.5%, also indicates the enhancement of the catalytic performance of the material significantly more favorable to improve the adsorption efficiency of transitional compounds. In contrast, an increase of the atomic O/C ratio in RB, 0.51 delineated high breakdown of the cellulosic component, which is favorable for biofuel purpose. 13.98% SiO2 reduction in RB confirmed ash content minimization and better quality of fuel properties. Therefore, the rice husk biochar through HTC can be considered a suitable material for further application to treat wastewater and generate bioenergy.
Hossain, SM, Park, H, Kang, H-J, Kim, JB, Tijing, L, Rhee, I, Jun, Y-S, Shon, HK & Kim, J-H 2020, 'Preparation and Characterization of Photoactive Anatase TiO2 from Algae Bloomed Surface Water', Catalysts, vol. 10, no. 4, pp. 452-452.
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The purpose of the study was to effectively treat algae bloomed water while using a Ti-based coagulant (TiCl4) and recover photoactive novel anatase TiO2 from the flocculated sludge. Conventional jar tests were conducted in order to evaluate the coagulation efficiency, and TiCl4 was found superior compared to commercially available poly aluminum chloride (PAC). At a dose of 0.3 g Ti/L, the removal rate of turbidity, chemical oxygen demand (COD), and total phosphorus (TP) were measured as 99.8%, 66.7%, and 96.9%, respectively. Besides, TiO2 nanoparticles (NPs) were recovered from the flocculated sludge and scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDX), and X-ray diffraction (XRD) analysis confirmed the presence of only anatase phase. The recovered TiO2 was found to be effective in removing gaseous CH3CHO and NOx under UV-A lamp at a light intensity of 10 W/m2. Additionally, the TiO2 mixed mortar blocks that were prepared in this study successfully removed atmospheric nitrogen oxide (NOx) under UV irradiance. This study is one of the first to prepare anatase TiO2 from flocculated algal sludge and it showed promising results. Further research on this novel TiO2 concerning internal chemical bonds and shift in the absorbance spectrum could explore several practical implications.
Hossain, SM, Park, H, Kang, H-J, Mun, JS, Tijing, L, Rhee, I, Kim, J-H, Jun, Y-S & Shon, HK 2020, 'Modified Hydrothermal Route for Synthesis of Photoactive Anatase TiO2/g-CN Nanotubes from Sludge Generated TiO2', Catalysts, vol. 10, no. 11, pp. 1350-1350.
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Titania nanotube was prepared from sludge generated TiO2 (S-TNT) through a modified hydrothermal route and successfully composited with graphitic carbon nitride (g-CN) through a simple calcination step. Advanced characterization techniques such as X-ray diffraction, scanning and transmission electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, UV/visible diffuse reflectance spectroscopy, and photoluminescence analysis were utilized to characterize the prepared samples. A significant improvement in morphological and optical bandgap was observed. The effective surface area of the prepared composite increased threefold compared with sludge generated TiO2. The optical bandgap was narrowed to 3.00 eV from 3.18 in the pristine sludge generated TiO2 nanotubes. The extent of photoactivity of the prepared composites was investigated through photooxidation of NOx in a continuous flow reactor. Because of extended light absorption of the as-prepared composite, under visible light, 19.62% of NO removal was observed. On the other hand, under UV irradiation, owing to bandgap narrowing, although the light absorption was compromised, the impact on photoactivity was compensated by the increased effective surface area of 153.61 m2/g. Hence, under UV irradiance, the maximum NO removal was attained as 32.44% after 1 h of light irradiation. The proposed facile method in this study for the heterojunction of S-TNT and g-CN could significantly contribute to resource recovery from water treatment plants and photocatalytic atmospheric pollutant removal.
Hosseinzadeh, A, Baziar, M, Alidadi, H, Zhou, JL, Altaee, A, Najafpoor, AA & Jafarpour, S 2020, 'Application of artificial neural network and multiple linear regression in modeling nutrient recovery in vermicompost under different conditions', Bioresource Technology, vol. 303, pp. 122926-122926.
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© 2020 Elsevier Ltd Vermicomposting is one of the best technologies for nutrient recovery from solid waste. This study aims to assess the efficiency of Artificial Neural Network (ANN) and Multiple Linear Regression (MLR) models in predicting nutrient recovery from solid waste under different vermicompost treatments. Seven chemical and biological indices were studied as input variables to predict total nitrogen (TN) and total phosphorus (TP) recovery. The developed ANN and MLR models were compared by statistical analysis including R-squared (R2), Adjusted-R2, Root Mean Square Error and Absolute Average Deviation. The results showed that vermicomposting increased TN and TP proportions in final products by 1.5 and 16 times. The ANN models provided better prediction for TN and TP with R2 of 0.9983 and 0.9991 respectively, compared with MLR models with R2 of 0.834 and 0.729. TN and C/N ratio were key factors for TP and TN prediction by ANN with percentages of 17.76 and 18.33.
Hosseinzadeh, A, Zhou, JL, Altaee, A, Baziar, M & Li, D 2020, 'Effective modelling of hydrogen and energy recovery in microbial electrolysis cell by artificial neural network and adaptive network-based fuzzy inference system', Bioresource Technology, vol. 316, pp. 123967-123967.
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Hosseinzadeh, A, Zhou, JL, Altaee, A, Baziar, M & Li, X 2020, 'Modeling water flux in osmotic membrane bioreactor by adaptive network-based fuzzy inference system and artificial neural network', Bioresource Technology, vol. 310, pp. 123391-123391.
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Osmotic Membrane Bioreactor (OMBR) is an emerging technology for wastewater treatment with membrane fouling as a major challenge. This study aims to develop Adaptive Network-based Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN) models in simulating and predicting water flux in OMBR. Mixed liquor suspended solid (MLSS), electrical conductivity (EC) and dissolved oxygen (DO) were used as model inputs. Good prediction was demonstrated by both ANFIS models with R2 of 0.9755 and 0.9861, and ANN models with R2 of 0.9404 and 0.9817, for thin film composite (TFC) and cellulose triacetate (CTA) membranes, respectively. The root mean square error for TFC (0.2527) and CTA (0.1230) in ANFIS models was lower than in ANN models at 0.4049 and 0.1449. Sensitivity analysis showed that EC was the most important factor for both TFC and CTA membranes in ANN models, while EC (TFC) and MLSS (CTA) are key parameters in ANFIS models.
Hu, X, Zhang, X, Ngo, HH, Guo, W, Wen, H, Li, C, Zhang, Y & Ma, C 2020, 'Comparison study on the ammonium adsorption of the biochars derived from different kinds of fruit peel', Science of The Total Environment, vol. 707, pp. 135544-135544.
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Application of biochars to remove inorganic nitrogen (NH4+, NO2-, NH3, NO, NO2, N2O) from wastewater and agricultural fields has gained a significant interest. This study aims to investigate the relationship between ammonium sorption and physicochemical properties of biochars derived from different kinds of fruit peel. Biochars from three species of fruit peel (orange, pineapple and pitaya) were prepared at 300, 400, 500 and 600 °C with the residence time of 2 h and 4 h. Their characteristics and sorption for ammonium was evaluated. The results show a clear effect of pyrolysis conditions on physicochemical properties of biochars, including elemental composition, functional groups and pH. The maximum NH4+ adsorption capacities were associated with biochars of orange peel (4.71 mg/g) and pineapple peel (5.60 mg/g) produced at 300 °C for 2 h. The maximum NH4+ adsorption capacity of the pitaya peel biochar produced at 400 °C for 2 h was 2.65 mg/g. For all feedstocks, biochars produced at low temperatures showed better NH4+ adsorption capacity. It was found that biochars had better adsorption efficiency on ammonium at a pH of 9. Adsorption kinetics of ammonium on biochars followed the pseudo-second-order kinetic model while Langmuir isotherm model could well simulate the adsorption behavior of ammonium on biochars. The adsorption mechanism of ammonium on biochars predominantly involved surface complexation, cation exchange and electrostatic attraction. Conclusively, the fruit peel-derived biochars can be used as an alternative to conventional sorbents in water treatment.
Hu, Y, Zang, Y, Yang, Y, Duan, A, Wang, XC, Ngo, HH, Li, Y-Y & Du, R 2020, 'Zero-valent iron addition in anaerobic dynamic membrane bioreactors for preconcentrated wastewater treatment: Performance and impact', Science of The Total Environment, vol. 742, pp. 140687-140687.
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Wastewater preconcentration to capture abundant organics is promising for facilitating subsequent anaerobic digestion (AD) to recover bioenergy, however research efforts are still needed to verify the effectiveness of such an emerging strategy as carbon capture plus AD. Therefore, lab-scale anaerobic dynamic membrane bioreactors (AnDMBRs) without and with the addition of zero-valent iron (ZVI) (i.e., AnDMBR1 versus AnDMBR2) were developed for preconcentrated domestic wastewater (PDW) treatment, and the impact of ZVI addition on process performance and associated mechanisms were investigated. The stepwise addition of ZVI from 2 to 4 to 6 g/L improved the treatment performance as COD removal slightly increased and TP removal and methane production were enhanced by 53.3%-62.9% and 22.6%-31.3%, respectively, in consecutive operational phases. However, the average increasing rate of the transmembrane pressure (TMP) in AnDMBR2 (0.18 kPa/d) was obviously higher than that in AnDMBR1 (0.05 kPa/d), indicating an unfavorable impact of dosing ZVI on the dynamic membrane (DM) filtration performance. ZVI that has transformed to iron ions (mainly Fe2+) can behave as a coagulant, electron donor or inorganic foulant, thus enabling the excellent removal of dissolved phosphorous, enhancing the enrichment and activities of specific methanogens and causing the formation of a compact DM layer. Morphological, componential, and microbial community analyses provided new insights into the functional mechanisms of ZVI added to membrane-assisted anaerobic digesters, indicating that ZVI has the potential to improve bioenergy production and resource recovery, while optimizing the ZVI dosage should be considered to alleviate membrane fouling.
Huang, Q-S, Wang, C, Wei, W & Ni, B-J 2020, 'Magnetic poly(aniline-co-5-sulfo-2-anisidine) as multifunctional adsorbent for highly effective co-removal of aqueous Cr(VI) and 2,4-Dichlophenol', Chemical Engineering Journal, vol. 387, pp. 124152-124152.
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© 2020 Elsevier B.V. The common coexistence of heavy metal ions (HMIs) and toxic organic matters (OMs) arouses public concerns for their combined toxicity and carcinogenicity. The magnetic poly[aniline(AN)-co-5-sulfo-2-anisidine(SA)] (AN-SA/Fe3O4) was synthesized by an oxidative copolymerization method for the highly-effectively simultaneous removal of Cr(VI) and 2,4-dichlorophenol (2,4-DCP) from aqueous solution. The novel adsorbent exhibited ultra-strong adsorption capacities for sole Cr(VI) and sole 2,4-DCP. The mechanism studies revealed that Cr(VI) species (HCrO4− and Cr2O72− in solution pH as 5) were reduced to Cr(III) by the –NH–/–NH2 groups after attaching to the protonated binding sites of AN-SA/Fe3O4 through electrostatic attraction. By contrast, multiple reactions involving the n-π electron donor-acceptor (EDA) interaction, π-π stacking and hydrogen bond contributed to the elimination of 2,4-DCP. In binary system, the coexistent Cr(VI) and 2,4-DCP elevated mutual adsorption capacities by 88.1% and 102.1%, respectively. Specially, 2,4-DCP can form bridge interactions with both Cr(VI) and Cr(III) due to conjugate effect. This property enabled Cr(VI) to additionally link to the hydrophobic sites, except for the hydrophilic sites, via 2,4-DCP bridges. Moreover, the produced Cr(III) can forcefully captured 2,4-DCP with the electron-rich groups (i.e., [sbnd]NH[sbnd], [sbnd]N[dbnd], [sbnd]SO3H, [sbnd]OCH3) on AN-SA/Fe3O4 to form the multi-components complexes. The bridge interactions (i.e., n-π EDA interaction, complexation) created the newly available sites for Cr(VI) and 2,4-DCP, resulting in enlarged adsorbance and synchronous removal on AN-SA/Fe3O4 in coexisting system. In addition, the high proportion of [sbnd]N[dbnd] groups generated by Cr(VI) oxidation also devoted to the uptake enhancement due to its strong affinity for 2,4-DCP. Overall, the high-performance and synergistic removal qualified AN-SA/Fe3O4 as a multifunctional adsorbent for the...
Huang, Q-S, Wu, W, Wei, W, Song, L, Sun, J & Ni, B-J 2020, 'Highly-efficient Pb2+ removal from water by novel K2W4O13 nanowires: Performance, mechanisms and DFT calculation', Chemical Engineering Journal, vol. 381, pp. 122632-122632.
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© 2019 Elsevier B.V. As one of the most toxic heavy metals, lead ions (Pb2+) contamination arouses increasing public concern for high carcinogenicity and neurotoxicity. In this study, a modified hydrothermal method was designed to fabricate novel hexagonal K2W4O13 nanowires to achieve highly-efficient Pb2+ removal from water. Attractively, the as-prepared K2W4O13 exhibited large uptake capacity (228.83 mg/g), fast kinetic (141.67 mg/g in 30 min), superior acid-resistance (75% of removal at pH = 2) and excellent reusability (over 95% of removal after 5 runs) toward Pb2+ adsorption. The Langmuir isotherm and pseudo-second-order kinetic model gave a better fit to the adsorption experimental data. The Pb2+ adsorption process on K2W4O13 was revealed to be a spontaneous, exothermic, film diffusion limited chemisorption reaction. The mechanism studied elucidated that both ion-exchange and complexation were involved in Pb2+ adsorption, with each accounting for approximate 50% of Pb2+ elimination. Through density functional theory (DFT) calculation, the equatorial oxygen was found to be more accessible for Pb attachment than the axial corner oxygen from [WO6] octahedra. Electron pairs from the adjacent O atoms would transfer to the empty orbitals of Pb atoms after adsorption, causing the Pb2+ removal via metal-ligand complexation.
Huang, Y, Mok, W-C, Yam, Y-S, Zhou, JL, Surawski, NC, Organ, B, Chan, EFC, Mofijur, M, Mahlia, TMI & Ong, HC 2020, 'Evaluating in-use vehicle emissions using air quality monitoring stations and on-road remote sensing systems', Science of The Total Environment, vol. 740, pp. 139868-139868.
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Huang, Y, Ng, ECY, Surawski, NC, Yam, Y-S, Mok, W-C, Liu, C-H, Zhou, JL, Organ, B & Chan, EFC 2020, 'Large eddy simulation of vehicle emissions dispersion: Implications for on-road remote sensing measurements', Environmental Pollution, vol. 259, pp. 113974-113974.
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© 2020 Elsevier Ltd On-road remote sensing technology measures the concentration ratios of pollutants over CO2 in the exhaust plume in half a second when a vehicle passes by a measurement site, providing a rapid, non-intrusive and economic tool for vehicle emissions monitoring and control. A key assumption in such measurement is that the emission ratios are constant for a given plume. However, there is a lack of study on this assumption, whose validity could be affected by a number of factors, especially the engine operating conditions and turbulence. To guide the development of the next-generation remote sensing system, this study is conducted to investigate the effects of various factors on the emissions dispersion process in the vehicle near-wake region and their effects on remote sensing measurement. The emissions dispersion process is modelled using Large Eddy Simulation (LES). The studied factors include the height of the remote sensing beam, vehicle speed, acceleration and side wind. The results show that the measurable CO2 and NO exhaust plumes are relatively short at 30 km/h cruising speed, indicating that a large percentage of remote sensing readings within the measurement duration (0.5 s) are below the sensor detection limit which would distort the derived emission ratio. In addition, the valid measurement region of NO/CO2 emission ratio is even shorter than the measurable plume and is at the tailpipe height. The effect of vehicle speed (30–90 km/h) on the measurable plume length is insignificant. Under deceleration condition, the length of the valid NO/CO2 measurement region is shorter than under cruising and acceleration conditions. Side winds from the far-tailpipe direction have a significant effect on remote sensing measurements. The implications of these findings are discussed and possible solutions to improve the accuracy of remote sensing measurement are proposed.
Huang, Y, Surawski, NC, Yam, Y-S, Lee, CKC, Zhou, JL, Organ, B & Chan, EFC 2020, 'Re-evaluating effectiveness of vehicle emission control programmes targeting high-emitters', Nature Sustainability, vol. 3, no. 11, pp. 904-907.
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© 2020, The Author(s), under exclusive licence to Springer Nature Limited. Estimating emission distribution within a vehicle fleet is critical for air pollution control. Previous studies reported that more than half of total fleet emissions were produced by only the highest 10% emitters, making repairing or deregistering a small percentage of high-emitters the most cost-effective measure to control vehicle emissions. With diesel emissions data from chassis dynamometer testing and on-road remote sensing, we show that such a strategy may be oversimplified.
Huang, Y, Yu, Y, Yam, Y-S, Zhou, JL, Lei, C, Organ, B, Zhuang, Y, Mok, W-C & Chan, EFC 2020, 'Statistical evaluation of on-road vehicle emissions measurement using a dual remote sensing technique', Environmental Pollution, vol. 267, pp. 115456-115456.
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On-road remote sensing (RS) is a rapid, non-intrusive and economical tool to monitor and control the emissions of in-use vehicles, and currently is gaining popularity globally. However, a majority of studies used a single RS technique, which may bias the measurements since RS only captures a snapshot of vehicle emissions. This study aimed to use a unique dual RS technique to assess the characteristics of on-road vehicle emissions. The results show that instantaneous vehicle emissions are highly dynamic under real-world driving conditions. The two emission factors measured by the dual RS technique show little correlation, even under the same driving condition. This indicates that using the single RS technique may be insufficient to accurately represent the emission level of a vehicle based on one measurement. To increase the accuracy of identifying high-emitting vehicles, using the dual RS technique is essential. Despite little correlation, the dual RS technique measures the same average emission factors as the single RS technique does when a large number of measurements are available. Statistical analysis shows that both RS systems demonstrate the same Gamma distribution with ≥200 measurements, leading to converged mean emission factors for a given vehicle group. These findings point to the need for a minimum sample size of 200 RS measurements in order to generate reliable emission factors for on-road vehicles. In summary, this study suggests that using the single or dual RS technique will depend on the purpose of applications. Both techniques have the same accuracy in calculating average emission factors when sufficient measurements are available, while the dual RS technique is more accurate in identifying high-emitters based on one measurement only.
Huang, Y, Zhou, J, Yu, Y, Mok, W-C, Lee, C & Yam, Y-S 2020, 'Uncertainty in the Impact of the COVID-19 Pandemic on Air Quality in Hong Kong, China', Atmosphere, vol. 11, no. 9, pp. 914-914.
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Strict social distancing rules are being implemented to stop the spread of COVID-19 pandemic in many cities globally, causing a sudden and extreme change in the transport activities. This offers a unique opportunity to assess the effect of anthropogenic activities on air quality and provides a valuable reference to the policymakers in developing air quality control measures and projecting their effectiveness. In this study, we evaluated the effect of the COVID-19 lockdown on the roadside and ambient air quality in Hong Kong, China, by comparing the air quality monitoring data collected in January–April 2020 with those in 2017–2019. The results showed that the roadside and ambient NO2, PM10, PM2.5, CO and SO2 were generally reduced in 2020 when comparing with the historical data in 2017–2019, while O3 was increased. However, the reductions during COVID-19 period (i.e., February–April) were not always higher than that during pre-COVID-19 period (i.e., January). In addition, there were large seasonal variations in the monthly mean pollutant concentrations in every year. This study implies that one air pollution control measure may not generate obvious immediate improvements in the air quality monitoring data and its effectiveness should be evaluated carefully to eliminate the effect of seasonal variations.
Huang, Z, Wang, S, Dewhurst, RD, Ignat'ev, NV, Finze, M & Braunschweig, H 2020, 'Boron: Its Role in Energy‐Related Processes and Applications', Angewandte Chemie International Edition, vol. 59, no. 23, pp. 8800-8816.
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AbstractBoron's unique position in the Periodic Table, that is, at the apex of the line separating metals and nonmetals, makes it highly versatile in chemical reactions and applications. Contemporary demand for renewable and clean energy as well as energy‐efficient products has seen boron playing key roles in energy‐related research, such as 1) activating and synthesizing energy‐rich small molecules, 2) storing chemical and electrical energy, and 3) converting electrical energy into light. These applications are fundamentally associated with boron's unique characteristics, such as its electron‐deficiency and the availability of an unoccupied p orbital, which allow the formation of a myriad of compounds with a wide range of chemical and physical properties. For example, boron's ability to achieve a full octet of electrons with four covalent bonds and a negative charge has led to the synthesis of a wide variety of borate anions of high chemical and electrochemical stability—in particular, weakly coordinating anions. This Review summarizes recent advances in the study of boron compounds for energy‐related processes and applications.
Hughes, DJ, Crosswell, JR, Doblin, MA, Oxborough, K, Ralph, PJ, Varkey, D & Suggett, DJ 2020, 'Dynamic variability of the phytoplankton electron requirement for carbon fixation in eastern Australian waters', Journal of Marine Systems, vol. 202, pp. 103252-103252.
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© 2019 Elsevier B.V. Fast Repetition Rate fluorometry (FRRf) generates high-resolution measures of phytoplankton primary productivity as electron transport rates (ETRs). How ETRs scale to corresponding inorganic carbon (C) uptake rates (the so-called electron requirement for carbon fixation, Φe,C), inherently describes the extent and effectiveness with which absorbed light energy drives C-fixation. However, it remains unclear whether and how Φe,C follows predictable patterns for oceanographic datasets spanning physically dynamic, and complex, environmental gradients. We utilise a unique high-throughput approach, coupling ETRs and 14C-incubations to produce a semi-continuous dataset of Φe,C (n = 80), predominantly from surface waters, along the Australian coast (Brisbane to the Tasman Sea), including the East Australian Current (EAC). Environmental conditions along this transect could be generally grouped into cooler, more nutrient-rich waters dominated by larger size-fractionated Chl-a (>10 μm) versus warmer nutrient-poorer waters dominated by smaller size-fractionated Chl-a (<2 μm). Whilst Φe,C was higher for warmer water samples, environmental conditions alone explained <20% variance of Φe,C, and changes in predominant size-fraction(s) distributions of Chl-a (biomass) failed to explain variance of Φe,C. Instead, normalised Stern-Volmer non-photochemical quenching (NPQNSV = F0′/Fv′) was a better predictor of Φe,C, explaining ~55% of observed variability. NPQNSV is a physiological descriptor that accounts for changes in both long-term driven acclimation in non-radiative decay, and quasi-instantaneous PSII downregulation, and thus may prove a useful predictor of Φe,C across physically-dynamic regimes, provided the slope describing their relationship is predictable. We also consider recent advances in fluorescence-based corrections to evaluate the potential role of baseline fluorescence (Fb) in contributing to overestimation of Φe,C and the correlation be...
Hurtado-McCormick, V, Kahlke, T, Krix, D, Larkum, A, Ralph, PJ & Seymour, JR 2020, 'Seagrass leaf reddening alters the microbiome of Zostera muelleri', Marine Ecology Progress Series, vol. 646, pp. 29-44.
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Seagrasses host an extremely diverse microbiome that plays fundamental roles in seagrass health and productivity but may be sensitive to shifts in host physiology. Here, we observed a leaf reddening phenomenon in Zostera muelleri and characterized bacterial assemblages associated with green and reddened leaves to determine whether this change in leaf pigmentation stimulates shifts in the seagrass microbiome. Using 16S rRNA gene amplicon sequencing, we observed that the microbiome associated with 4 different leaf pigmentation categories (i.e. green, white, purple and black) differed significantly, with substantial changes in microbiome composition when the tissue is whitened (non-pigmented). Actinobacteria, Rhodobacteraceae, Erythrobacter, Sulfitobacter and Granulosicoccus were enriched in black and/or purple tissues and discriminated these microbiomes from those associated with green leaves. Contrastingly, all ‘discriminatory’ zero-radius operational taxonomic units (zOTUs) were depleted within the communities associated with white samples. While 40% of the abundant zOTUs identified were exclusively associated with a single pigmentation category, only 3% were shared across all categories, indicating partitioning of the phyllosphere microbiome. However, a significant proportion of the ‘normal’ (green) leaf core microbiome was also retained in the core communities associated with black (70%) and purple (70%) tissues. Contrastingly, no core zOTUs were maintained in the white tissues. These results indicate that environmentally driven physiological shifts in seagrasses, such as leaf reddening expressed in response to high irradiance, can impact the seagrass leaf microbiome, resulting in significant shifts in the microbiome of reddened leaves with the most extreme expression (in white tissue...
Huy Tran, V, Lim, S, Jun Park, M, Suk Han, D, Phuntsho, S, Park, H, Matsuyama, H & Kyong Shon, H 2020, 'Fouling and performance of outer selective hollow fiber membrane in osmotic membrane bioreactor: Cross flow and air scouring effects', Bioresource Technology, vol. 295, pp. 122303-122303.
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© 2019 Elsevier Ltd This study assessed impacts of cross-flow velocity (CFV) and air scouring on the performance and membrane fouling mitigation of a side-stream module containing outer-selective hollow fiber thin film composite forward osmosis membrane in osmosis membrane bioreactor (OMBR) system for urban wastewater treatment. CFV of draw solution was optimized, followed by the impact assessment of three CFVs on feed solution (FS) stream and periodic injection of air scouring into the side-stream module. Overall, the OMBR system exhibited high and stable performance with initial water flux of approximately 15 LMH, high removal efficiencies of bulk organic matter and nutrients. While FS's CFVs insignificantly affected the performance and membrane fouling, regular air scouring showed substantial impact with better performance and high efficiency in mitigating membrane fouling. These results indicated that periodic air scouring can be applied into the side-stream membrane module for efficient fouling mitigation without interruption the operation of the OMBR system.
Ibrar, I, Altaee, A, Zhou, JL, Naji, O & Khanafer, D 2020, 'Challenges and potentials of forward osmosis process in the treatment of wastewater', Critical Reviews in Environmental Science and Technology, vol. 50, no. 13, pp. 1339-1383.
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© 2019, © 2019 Taylor & Francis Group, LLC. An emerging osmotically driven membrane process, forward osmosis has attracted growing attention in the field of desalination and wastewater treatment. The present study provides a critical review of the forward osmosis process for wastewater treatment focusing on most recent studies. Forward osmosis is one of the technologies that has been widely studied for the treatment of a wide range of wastewater because of its low fouling and energy consumption compared to conventional techniques for wastewater treatment. To date, forward osmosis has limited applications in the field of wastewater treatment due to several technical and economic concerns. Although membrane cost is one of the critical issues that limit the commercial application of forward osmosis, there are other obstacles such as membrane fouling, finding an ideal draw solution that can easily be recycled, concentration polarization and reverse salt diffusion. Innovative technologies for in-situ real-time fouling monitoring can give us new insights into fouling mechanisms and fouling control strategies in forward osmosis. This study evaluated recent advancements in forward osmosis technology for wastewater treatment and the main challenges that need to be addressed in future research work.
Ibrar, I, Yadav, S, Altaee, A, Hawari, A, Nguyen, V & Zhou, J 2020, 'A novel empirical method for predicting concentration polarization in forward osmosis for single and multicomponent draw solutions', Desalination, vol. 494, pp. 114668-114668.
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Ibrar, I, Yadav, S, Altaee, A, Samal, AK, Zhou, JL, Nguyen, TV & Ganbat, N 2020, 'Treatment of biologically treated landfill leachate with forward osmosis: Investigating membrane performance and cleaning protocols', Science of The Total Environment, vol. 744, pp. 140901-140901.
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This study presents systematic investigations to evaluate the performance, rejection rate, fouling, cleaning protocols and impact of physical and chemical cleaning strategies on the performance of commercial cellulose triacetate (CTA) membrane. The treatment of landfill leachate (LFL) solution was performed in the active layer facing feed solution and support layer facing the draw solution (AL-FS mode), and active layer facing the draw solution and support layer facing the feed solution (AL-DS mode). Compared to the AL-FS mode, a higher flux for AL-DS mode was achieved, but membrane fouling was more severe in the latter. In both membrane orientations, the rejection rate of the FO membrane to heavy ions and contaminants in the wastewater was between 93 and 99%. Physical and chemical cleaning strategies were investigated to recover the performance of the FO membrane and to study the impact of cleaning methods on the membrane rejection rate. Physical cleaning with hot water at 35 °C and osmotic backwashing with 1.5 M NaCl demonstrated excellent water flux recovery compared to chemical cleaning. In the chemical cleaning, an optimal concentration of 3% hydrogen peroxide was determined for 100% flux recovery of the fouled membrane. However, slight membrane damage was achieved at this concentration on the active layer side. Alkaline cleaning at pH 11 was more effective than acid cleaning at pH 4, although both protocols compromised the membrane rejection rate for some toxic ions. A comparison of the membrane long-term performance found that cleaning with osmotic backwashing and hot water were effective methods to restore water flux without comprising the membrane rejection rate. Overall, it was found that physical cleaning protocols are superior to chemical cleaning protocols for forward osmosis membrane fouled by landfill leachate wastewater.
Jamil, S, Loganathan, P, Kandasamy, J, Listowski, A, McDonald, JA, Khan, SJ & Vigneswaran, S 2020, 'Removal of organic matter from wastewater reverse osmosis concentrate using granular activated carbon and anion exchange resin adsorbent columns in sequence', Chemosphere, vol. 261, pp. 127549-127549.
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Reverse osmosis concentrate (ROC) generated as a waste stream during reverse osmosis treatment of reclaimed wastewater, presents significant disposal challenges. This is because it causes environmental pollution when it is disposed to lands and natural water bodies. A long-term dynamic adsorption experiment was conducted by passing ROC from a wastewater reclamation plant, firstly through a granular activated carbon (GAC) column, and subsequently through an anion exchange resin (Purolite) column, for the removal of two major ROC pollutants, namely dissolved organic carbon (DOC) and microorganic pollutants (MOP). GAC removed most of the smaller-sized low molecular weight neutrals and building block fractions as well as the hydrophobic fraction of DOC with much less removal by the subsequent Purolite column. In contrast, the humics fraction was less well removed by the GAC column; however, Purolite column removed all that was remaining of this fraction. This study demonstrated that combining adsorbents having different affinities towards a variety of DOC fractions constitute an effective method of taking advantage of their different properties and achieving larger DOC removals. Almost 100% of all 17 MOPs were removed by the GAC column, even after 2880 bed volumes of continuous use. This contrasted with the DOC fractions' removal which was much lower.
Jamshaid, M, Masjuki, HH, Kalam, MA, Zulkifli, NWM, Arslan, A & Zulfattah, ZM 2020, 'Effect of Fatty Acid Methyl Ester on Fuel-Injector Wear Characteristics', Journal of Biobased Materials and Bioenergy, vol. 14, no. 3, pp. 327-339.
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This paper presents the experimental results carried out to evaluate the fatty acid methyl ester (FAME) obtained from cotton-seed oil and palm oil on fuel-injector wear characteristics. The cottonseed oil methyl ester (COME) and palm oil methyl ester (POME) were produced in the laboratory using alkaline transesterification. Gas chromatography based on 'BS EN 14103:2011' standard was used to analyze the percentage of fatty acids in COME and POME. The physicochemical properties of the two methyl esters were measured based on ASTM and EN standards. Various unique blends using cottonseed–palm oil methyl ester (CPME) were tested. Thirteen (13) different types of fuel blends were prepared from COME, POME, and petroleum diesel fuel (DF100). The wear and lubricity characteristics were measured using a high-frequency reciprocating rig (HFRR) based on ASTM D6079 standard. The worn surfaces of the specimen plates were evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The COME100, POME100, and CPME100 showed excellent lubricity properties for the fuel injector in terms of lower COF and wear coefficient when compared with DF100. COME100, POME100 and CPME100 showed lower average COF compared to DF100 by 16.9%, 13.9% and 16.1%, respectively. This may be due to the presence of unsaturated fatty acids in the methyl esters composition. Consequently, the fatty acid methyl esters can be used to reduce the friction and wear of the fuel injectors due to the improvement in the tribological properties of the fuel.
Jaramillo-Madrid, AC, Abbriano, R, Ashworth, J, Fabris, M, Pernice, M & Ralph, PJ 2020, 'Overexpression of Key Sterol Pathway Enzymes in Two Model Marine Diatoms Alters Sterol Profiles in Phaeodactylum tricornutum', Pharmaceuticals, vol. 13, no. 12, pp. 481-481.
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Sterols are a class of triterpenoid molecules with diverse functional roles in eukaryotic cells, including intracellular signaling and regulation of cell membrane fluidity. Diatoms are a dominant eukaryotic phytoplankton group that produce a wide diversity of sterol compounds. The enzymes 3-hydroxy-3-methyl glutaryl CoA reductase (HMGR) and squalene epoxidase (SQE) have been reported to be rate-limiting steps in sterol biosynthesis in other model eukaryotes; however, the extent to which these enzymes regulate triterpenoid production in diatoms is not known. To probe the role of these two metabolic nodes in the regulation of sterol metabolic flux in diatoms, we independently over-expressed two versions of the native HMGR and a conventional, heterologous SQE gene in the diatoms Thalassiosira pseudonana and Phaeodactylum tricornutum. Overexpression of these key enzymes resulted in significant differential accumulation of downstream sterol pathway intermediates in P. tricornutum. HMGR-mVenus overexpression resulted in the accumulation of squalene, cycloartenol, and obtusifoliol, while cycloartenol and obtusifoliol accumulated in response to heterologous NoSQE-mVenus overexpression. In addition, accumulation of the end-point sterol 24-methylenecholesta-5,24(24’)-dien-3β-ol was observed in all P. tricornutum overexpression lines, and campesterol increased three-fold in P. tricornutum lines expressing NoSQE-mVenus. Minor differences in end-point sterol composition were also found in T. pseudonana, but no accumulation of sterol pathway intermediates was observed. Despite the successful manipulation of pathway intermediates and individual sterols in P. tricornutum, total sterol levels did not change significantly in transformed lines, suggesting the existence of tight pathway regulation to maintain total sterol content.
Jaramillo-Madrid, AC, Ashworth, J & Ralph, PJ 2020, 'Levels of Diatom Minor Sterols Respond to Changes in Temperature and Salinity', Journal of Marine Science and Engineering, vol. 8, no. 2, pp. 85-85.
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Diatoms are a broadly distributed and evolutionarily diversified group of microalgae that produce a diverse range of sterol compounds. Sterols are triterpenoids that play essential roles in membrane-related processes in eukaryotic cells. Some sterol compounds possess bioactivities that promote human health and are currently used as nutraceuticals. The relationship between sterol diversity in diatoms and their acclimation to different environments is not well understood. In this study, we investigated the occurrence of different sterol types across twelve diatom species, as well as the effect of temperature reduction and changes in salinity on the sterol contents of three model diatom species. In the diatoms Thalassiosira pseudonana, Phaeodactylum tricornutum and Chaetoceros muelleri, we found that changes in the relative contents of minor sterols accompanied shifts in temperature and salinity. This may be indicative of acquired adaptive traits in diatom metabolism.
Jaramillo-Madrid, AC, Ashworth, J, Fabris, M & Ralph, PJ 2020, 'The unique sterol biosynthesis pathway of three model diatoms consists of a conserved core and diversified endpoints', Algal Research, vol. 48, pp. 101902-101902.
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© 2020 Diatoms produce a wide diversity of sterols among different species, the biosynthesis and conservation of which is not yet fully understood. To investigate the conservation and divergence of sterol biosynthesis pathways among diatoms, we performed comparative metabolic profiling and transcriptomics for a centric diatom (Thalassiosira pseudonana), a pennate diatom (Phaeodactylum tricornutum) and a chaetocerid (Chaetoceros muelleri) in response to inhibitors of enzymes involved in sterol biosynthesis. These three model diatoms, which are representative of distinct clades, share a unique core phytosterol biosynthesis pathway that relies on a terbinafine-insensitive alternative squalene epoxidase and the cyclization of 2,3-epoxysqualene into cycloartenol by a conserved oxidosqualene cyclase. Lineage-specific divergence in the synthesis of sterol precursors was found in the species analyzed. Cholesterol synthesis in diatoms seems to occur via cycloartenol rather than lanosterol. The diversification of natural sterols produced by each species appears to occur downstream of all experimentally targeted enzymes, suggesting adaptive specialization in terminal synthesis pathways.
Jenifer A, A, Chandran, T, Muthunarayanan, V, Ravindran, B, Nguyen, VK, Nguyen, XC, Bui, X-T, Ngo, HH, Nguyen, XH, Chang, SW & Nguyen, DD 2020, 'Evaluation of efficacy of indigenous acidophile- bacterial consortia for removal of pollutants from coffee cherry pulping wastewater', Bioresource Technology Reports, vol. 11, pp. 100533-100533.
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The efficiency of indigenous bacteria to remove colour, TDS and COD pollutants from coffee cherry pulping wastewater (CCPWW) in an acidic pH without any manipulation of the effluent was studied. For the removal of such pollutants, the CCPWW was subjected to treatment with four indigenous microbial test strains isolated from CCPWW and characterised using 16S rRNA molecular technique, namely Enterobacter ludwigii, Bacilllus cereus, Enterobacter aerogenes and Enterobacter cloacae. Among the individual microbial treatments, the Enterobacter cloacae bacterial strain removed higher amount of TDS (37.6%) and COD (40.1%). Treatment with the bacterial consortia removed about 40.9% TDS, 48.7% COD from CCPWW after 48 h. The correlation coefficient ‘r’ between TDS and COD removal for each individual treatment was 1, showed the positive linear relationship. The microbes had endured in the harsh–low pH environment of the effluent and effectively removed the pollutants without any addition of other nutrient support.
Ji, M, Hu, Z, Hou, C, Liu, H, Ngo, HH, Guo, W, Lu, S & Zhang, J 2020, 'New insights for enhancing the performance of constructed wetlands at low temperatures', Bioresource Technology, vol. 301, pp. 122722-122722.
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Constructed wetlands (CWs) have been widely utilized for various types of wastewater treatment due to their merits, including high cost-effectiveness and easy operation. However, a few intrinsic drawbacks have always restricted their application and long-term stability, especially their weak performance at temperatures under 10 °C (low temperatures) due to the deterioration of microbial assimilation and plant uptake processes. The existing modifications to improve CWs performance from the direct optimization of internal components to the indirect adjunction of external resources promoted the wastewater treatment efficiency to a certain degree, but the sustainability and sufficiency of pollutants removal remains a challenge. With the goal of optimizing CW components, the integrity of the CW ecosystem and the removal of emerging pollutants, future directions for research should include radiation plant breeding, improvements to CW ecosystems, and the combination or integration of certain treatment processes with CWs to enhance wastewater treatment effects at low temperatures.
Khaleque, A, Alam, MM, Hoque, M, Mondal, S, Haider, JB, Xu, B, Johir, MAH, Karmakar, AK, Zhou, JL, Ahmed, MB & Moni, MA 2020, 'Zeolite synthesis from low-cost materials and environmental applications: A review', Environmental Advances, vol. 2, pp. 100019-100019.
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Zeolites with the three-dimensional structures occur naturally or can be synthesized in the laboratory. Zeolites have versatile applications such as environmental remediation, catalytic activity, biotechnological application, gas sensing and medicinal applications. Although, naturally occurring zeolites are readily available, nowadays, more emphasis is given on the synthesis of the zeolites due to their easy synthesis in the pure form, better ion exchange capabilities and uniform in size. Recently, much attention has also been paid on how zeolite is being synthesized from low-cost material (e.g., rice husk), particularly, by resolving the major environmental issues. Hence, the main purpose of this review is to make an effective resolution of zeolite synthesis methods together with potential applications in environmental engineering. Among different synthesis methods, hydrothermal method is commonly found to be used widely in the synthesis of various zeolites from inexpensive raw materials such as fly ash, rice husk ash, blast furnace slag, municipal solid waste, paper sludge, lithium slag and kaolin. Besides, future expectation in the field of synthetic zeolites research is also included.
Khan, JA, Nguyen, LN, Duong, HC & Nghiem, LD 2020, 'Acetic acid extraction from rumen fluid by forward osmosis', Environmental Technology & Innovation, vol. 20, pp. 101083-101083.
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Khanzada, NK, Farid, MU, Kharraz, JA, Choi, J, Tang, CY, Nghiem, LD, Jang, A & An, AK 2020, 'Removal of organic micropollutants using advanced membrane-based water and wastewater treatment: A review', Journal of Membrane Science, vol. 598, pp. 117672-117672.
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© 2019 Elsevier B.V. The rising consumption of pharmaceuticals, personal care products, and endocrine disruptive compounds for healthcare purposes and improving living standards has resulted in the widespread occurrence of organic micropollutants (MPs) in water and wastewater. Conventional water/wastewater treatment plants are faced with inherent limitations in tackling these compounds, leading to difficulties in the provision of secure and safe water supplies. In this context, membrane technology has been found to be a promising method for resolving this emerging concern. To ensure the suitability of membrane-based treatment processes in full-scale applications, we first need to develop a better understanding of the behavior of MPs and the mechanisms behind their removal using advanced membrane technologies. This review provides a thorough overview of the advanced membrane-based treatment methods available for the effective removal of MPs, including reverse osmosis, nanofiltration, ultrafiltration, forward osmosis, and membrane distillation.
Khlaifat, N, Altaee, A, Zhou, J & Huang, Y 2020, 'A review of the key sensitive parameters on the aerodynamic performance of a horizontal wind turbine using computational fluid dynamics modelling', AIMS Energy, vol. 8, no. 3, pp. 493-524.
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© 2020 the Author(s), licensee AIMS Press. Renewable energy technologies are receiving much attention to replacing power plants operated by fossil and nuclear fuels. Of all the renewable technologies, wind power has been successfully implemented in several countries. There are several parameters in the aerodynamic characteristics and design of the horizontal wind turbine. This paper highlights the key sensitive parameters that affect the aerodynamic performance of the horizontal wind turbine, such as environmental conditions, blade shape, airfoil configuration and tip speed ratio. Different turbulence models applied to predict the flow around the horizontal wind turbine using Computational Fluid Dynamics modeling are reviewed. Finally, the challenges and concluding remarks for future research directions in wind turbine design are discussed.
Khlaifat, N, Altaee, A, Zhou, J & Huang, Y 2020, 'A review of the key sensitive parameters on the aerodynamic performance of a horizontal wind turbine using Computational Fluid Dynamics modelling', AIMS Energy, vol. 8, no. 3, pp. 493-524.
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© 2020 the Author(s), licensee AIMS Press. Renewable energy technologies are receiving much attention to replacing power plants operated by fossil and nuclear fuels. Of all the renewable technologies, wind power has been successfully implemented in several countries. There are several parameters in the aerodynamic characteristics and design of the horizontal wind turbine. This paper highlights the key sensitive parameters that affect the aerodynamic performance of the horizontal wind turbine, such as environmental conditions, blade shape, airfoil configuration and tip speed ratio. Different turbulence models applied to predict the flow around the horizontal wind turbine using Computational Fluid Dynamics modeling are reviewed. Finally, the challenges and concluding remarks for future research directions in wind turbine design are discussed.
Khlaifat, N, Altaee, A, Zhou, J & Huang, Y 2020, 'Evaluation of wind resource potential using statistical analysis of probability density functions in New South Wales, Australia', Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, pp. 1-18.
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Wind energy is a vital part of Australia's energy mix. The first step in a wind power project at a particular site is to assess the wind resource potential and feasibility for wind energy production. Research on wind potential and statistical analysis has been done throughout the world. Currently, recent potential wind studies are lacking, especially in New South Wales (NSW), Australia. This study highlighted the feasibility of wind potential at four sites in NSW, namely Ballina, Merriwa, Deniliquin, and the Bega region. The type of wind speed distribution function dramatically affects the output of the available wind energy and wind turbine performance at a particular site. Therefore, the accuracy of four probability density functions was evaluated, namely Rayleigh, Weibull, Gamma, and Lognormal distributions. The outcomes showed Weibull provided the most accurate distribution. The annual average scale and shape parameters of Weibull distribution varied between 2.935-5.042 m/s and 1.137-2.096, respectively. The maximum shape and scale factors were at Deniliquin, while the minimum shape and scale factors were at Bega area. Assessment of power density indicated that Deniliquin had a marginal wind speed resource, while Ballina, Bega, and Merriwa had poor wind resources.
Khlaifat, N, Altaee, A, Zhou, J, Huang, Y & Braytee, A 2020, 'Optimization of a Small Wind Turbine for a Rural Area: A Case Study of Deniliquin, New South Wales, Australia', Energies, vol. 13, no. 9, pp. 2292-2292.
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The performance of a wind turbine is affected by wind conditions and blade shape. This study aimed to optimize the performance of a 20 kW horizontal-axis wind turbine (HAWT) under local wind conditions at Deniliquin, New South Wales, Australia. Ansys Fluent (version 18.2, Canonsburg, PA, USA) was used to investigate the aerodynamic performance of the HAWT. The effects of four Reynolds-averaged Navier–Stokes turbulence models on predicting the flows under separation condition were examined. The transition SST model had the best agreement with the NREL CER data. Then, the aerodynamic shape of the rotor was optimized to maximize the annual energy production (AEP) in the Deniliquin region. Statistical wind analysis was applied to define the Weibull function and scale parameters which were 2.096 and 5.042 m/s, respectively. The HARP_Opt (National Renewable Energy Laboratory, Golden, CO, USA) was enhanced with design variables concerning the shape of the blade, rated rotational speed, and pitch angle. The pitch angle remained at 0° while the rising wind speed improved rotor speed to 148.4482 rpm at rated speed. This optimization improved the AEP rate by 9.068% when compared to the original NREL design.
Kim, DI, Gonzales, RR, Dorji, P, Gwak, G, Phuntsho, S, Hong, S & Shon, H 2020, 'Efficient recovery of nitrate from municipal wastewater via MCDI using anion-exchange polymer coated electrode embedded with nitrate selective resin', Desalination, vol. 484, pp. 114425-114425.
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Kim, SY, Choo, Y, Bilodeau, RA, Yuen, MC, Kaufman, G, Shah, DS, Osuji, CO & Kramer-Bottiglio, R 2020, 'Sustainable manufacturing of sensors onto soft systems using self-coagulating conductive Pickering emulsions', Science Robotics, vol. 5, no. 39, p. eaay3604.
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An ethanol-based Pickering emulsion that spontaneously forms conductive composites is used to sustainably manufacture compliant strain sensors.
Kulandaivelu, J, Choi, PM, Shrestha, S, Li, X, Song, Y, Li, J, Sharma, K, Yuan, Z, Mueller, JF, Wang, C & Jiang, G 2020, 'Assessing the removal of organic micropollutants from wastewater by discharging drinking water sludge to sewers', Water Research, vol. 181, pp. 115945-115945.
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Discharging drinking water treatment sludge (DWTS) to sewers could be an efficient waste management strategy with the potential to replace chemical dosing for pollutant control. This study for the first time investigated the fate of 28 different organic micropollutants (MPs) due to the dosing of iron-rich and aluminum-rich DWTS in a pilot rising main sewer. Nine MPs had an initial rapid removal within 1-hr (i.e., 10-80%) due to Fe-DWTS dosing. The formation of FeS particles due to Fe-DWTS dosing was responsible for the removal of dissolved sulfides (80% reduction comparing to control sewer). Further particle characterization using SEM-EDS, XRD and ATR-FTIR confirmed that FeS particles formation played an important role in the removal of MPs from wastewater. Adsorption of MPs onto the FeS particles was likely the possible mechanism for their rapid removal. In comparison to iron-rich DWTS, aluminum-rich DWTS had very limited beneficial effects in removing MPs from wastewater. The degradability of degradable MPs, including caffeine, paraxanthine, paracetamol, metformin, cyclamate, cephalexin, and MIAA were not affected by the DWTS dosing. Some non-degradable MPs, including cotinine, hydroxycotinine, tramadol, gabapentin, desvenlafaxine, hydrochlorothiazide, carbamazepine, fluconazole, sulfamethoxazole, acesulfame, saccharin and sucralose were also not impacted by the DWTS dosing. This study systematically assessed the additional benefits of discharging Fe-DWTS to the sewer network i.e., the removal of MPs from the liquid phase thereby reducing its load to the treatment plant. The results corroborate the discharge of Fe-rich DWTS in sewers as an effective and beneficial way of managing the waste by-product.
Kulk, G, Platt, T, Dingle, J, Jackson, T, Jönsson, B, Bouman, H, Babin, M, Brewin, R, Doblin, M, Estrada, M, Figueiras, F, Furuya, K, González-Benítez, N, Gudfinnsson, H, Gudmundsson, K, Huang, B, Isada, T, Kovač, Ž, Lutz, V, Marañón, E, Raman, M, Richardson, K, Rozema, P, Poll, W, Segura, V, Tilstone, G, Uitz, J, Dongen-Vogels, V, Yoshikawa, T & Sathyendranath, S 2020, 'Primary Production, an Index of Climate Change in the Ocean: Satellite-Based Estimates over Two Decades', Remote Sensing, vol. 12, no. 5, pp. 826-826.
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Primary production by marine phytoplankton is one of the largest fluxes of carbon on our planet. In the past few decades, considerable progress has been made in estimating global primary production at high spatial and temporal scales by combining in situ measurements of primary production with remote-sensing observations of phytoplankton biomass. One of the major challenges in this approach lies in the assignment of the appropriate model parameters that define the photosynthetic response of phytoplankton to the light field. In the present study, a global database of in situ measurements of photosynthesis versus irradiance (P-I) parameters and a 20-year record of climate quality satellite observations were used to assess global primary production and its variability with seasons and locations as well as between years. In addition, the sensitivity of the computed primary production to potential changes in the photosynthetic response of phytoplankton cells under changing environmental conditions was investigated. Global annual primary production varied from 38.8 to 42.1 Gt C yr − 1 over the period of 1998–2018. Inter-annual changes in global primary production did not follow a linear trend, and regional differences in the magnitude and direction of change in primary production were observed. Trends in primary production followed directly from changes in chlorophyll-a and were related to changes in the physico-chemical conditions of the water column due to inter-annual and multidecadal climate oscillations. Moreover, the sensitivity analysis in which P-I parameters were adjusted by ±1 standard deviation showed the importance of accurately assigning photosynthetic parameters in global and regional calculations of primary production. The assimilation number of the P-I curve showed strong relationships with environmental variables such as temperature and had a practically one-to-one relationship with the magnitude of change in primary product...
Lau, AKS, Bilad, MR, Nordin, NAHM, Faungnawakij, K, Narkkun, T, Wang, DK, Mahlia, TMI & Jaafar, J 2020, 'Effect of membrane properties on tilted panel performance of microalgae biomass filtration for biofuel feedstock', Renewable and Sustainable Energy Reviews, vol. 120, pp. 109666-109666.
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© 2019 Elsevier Ltd Efficient membrane-based technology for microalgae harvesting can be achieved via application effective membrane fouling control coupled with appropriate membrane materials. This study explores the combined impact of membrane properties and the tilted panel system on filterability of Euglena sp broth, a potential source of biofuel feedstock. Four membranes from polyvinylidene difluoride (PVDF) and polysulfone (PSF) of PVDF-1, PVDF-3, PSF-1 and PSF-3 were evaluated. Generally, increasing aeration rate, tilting angle and lowering switching period enhance the system performance for all the tested membranes to give the highest permeances of 660, 724, 743 L/m2 h bar, respectively. Those values are among the highest reported in literature. The magnitude of the effect is affected by the membrane properties, mainly by pore size. Tilting without switching configuration is desirable for the membrane with a large pore size (PVDF-1, 0.42 μm) which produced the highest panel permeability of 724.3 (L/m2 h bar), which is >23% higher than the tilted with switching. For this membrane, intermittent aeration applied under switching mode worsened the pore blocking. Membranes with low pore sizes (0.11, 0.04 and 0.03 μm for PVDF-3, PSF-1 and PSF-3, respectively) excelled under switching mode since they are less prone to pore blocking due to smaller pore apertures. Overall results suggest that to gain the full benefit of the tilted panel, operational system of either one-sided without switching or two-sided involving switching must be tailored in conjunction with the desirable properties of the membranes. This finding can help to lower the energy input for microalgae-based biofuel production.
Lee, D, Woo, YC, Park, KH, Phuntsho, S, Tijing, LD, Yao, M, Shim, W-G & Shon, HK 2020, 'Polyvinylidene fluoride phase design by two-dimensional boron nitride enables enhanced performance and stability for seawater desalination', Journal of Membrane Science, vol. 598, pp. 117669-117669.
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© 2019 The instability of polyvinylidene fluoride (PVDF) membranes in membrane distillation (MD) for seawater desalination is still a problem, despite the tremendous effort expended to resolve this issue. Here, a simple and feasible approach for improving desalination performance through the incorporation of two-dimensional boron nitride nanosheets (BNNSs) in polyvinylidene fluoride-co-hexafluoropropene (PVDF-co-HFP) electrospun nanofiber membrane (BNs-PH) is proposed as well as demonstrate its origin for fundamental understanding. The BNs-PH membrane exhibits a stable water vapor flux (18 LMH) and superior salt rejection (99.99%), even after operation for 280 h (commercial PVDF: steep decay within 28 h; neat PH: wetting within 4 h). From structural/chemical analyses, the BNNSs play a crucial role in forming favorable phases of the PH polymer crystal structure, inducing a superhydrophobic surface with greater nanoporosity and higher heterogeneity as well as enhanced mechanical properties (increase of UTS: 13.4%; modulus: 1.2%) for long-term operation. Theoretical modeling results of an air-gap MD system are consistent with our experimental results. The approach introduced in this study can be applied to other desalination systems to boost various water treatment applications.
Lee, XJ, Ong, HC, Gan, YY, Chen, W-H & Mahlia, TMI 2020, 'State of art review on conventional and advanced pyrolysis of macroalgae and microalgae for biochar, bio-oil and bio-syngas production', Energy Conversion and Management, vol. 210, pp. 112707-112707.
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© 2020 Elsevier Ltd Algal biomass including macroalgae and microalgae show great potential as pyrolysis feedstock in generating energy-dense and valuable pyrolytic products such as bio-oil, biochar and bio-syngas. The chemical constituents of macroalgae and microalgae show great variations, especially their lipid, carbohydrate and protein contents, which could affect the qualities of the pyrolytic products. From the established conventional pyrolysis, the products produced from both macroalgae and microalgae show moderate energy contents (<34 MJ/kg). The review identifies the issues associated with development of conventional pyrolysis such as flash and intermediate pyrolysis. To enhance the production of biofuels from algal biomass, advanced or non-conventional pyrolysis techniques have been employed. Catalytic pyrolysis on algal biomass could reduce the nitrogenates and oxygenates in the biofuels. On top of that, co-pyrolysis with suitable feedstock shows great enhancement on the bio-oil yield. As for hydropyrolysis of algal biomass, their generated biofuels can produce up to 48 MJ/kg with high yield of bio-oil up to 50 wt%, comparable to conventional fuels. Microwave-assisted pyrolysis of algal biomass greatly shortens the processing time through advanced heating; however, favours the formation of bio-syngas by improving the yield up to 84 wt% depending on the feedstock used. Therefore, formation of biofuel fraction suitable for energy generation highly depends on the selected pyrolysis technologies.
Li, L, Song, K, Yeerken, S, Geng, S, Liu, D, Dai, Z, Xie, F, Zhou, X & Wang, Q 2020, 'Effect evaluation of microplastics on activated sludge nitrification and denitrification', Science of The Total Environment, vol. 707, pp. 135953-135953.
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A large amount of microplastics have entered conventional wastewater treatment plants, and their effects on activated sludge nitrification and denitrification are rarely reported. This study investigated the effects of microplastics on activated sludge nitrification and denitrification using five typical microplastics, namely, polyvinyl chloride (PVC), polypropylene, polyethylene, polystyrene, and polyester (PES) with concentrations of 0, 1000, 5000, and 10,000 particles/L. Results indicated that microplastics had negative effects on ammonia oxidation rate and low effect on nitrite oxidation rate during nitrification. The total inorganic nitrogen did not have much difference during 3 h nitrification under all the tested conditions. The addition of microplastics showed positive effects on denitrification, especially for PVC and PES at microplastic concentration of 5000 particles/L. Nitrification and denitrification did not evidently stop under all the tested conditions, indicating that the selected microplastic types and concentrations were not toxic to nitrification and denitrification within 3 h. The high abundance of PVC microplastics remarkably increased the nitrous oxide (N2O) emission during denitrification. The N2O emission in the test with 10,000 particle/L of PVC was 4.6times higher than the blank control. This study indicated that microplastics with <10,000 particle/L concentration in wastewater had low effects on nitrification and denitrification, whereas they had high effects on the N2O emission during denitrification.
Li, W, Wen, W, Chen, X, Ni, B, Lin, X & Fan, W 2020, 'Functional Evolving Patterns of Cortical Networks in Progression of Alzheimer’s Disease: A Graph-Based Resting-State fMRI Study', Neural Plasticity, vol. 2020, pp. 1-11.
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AD is a common chronic progressive neurodegenerative disorder. However, the understanding of the dynamic longitudinal change of the brain in the progression of AD is still rough and sometimes conflicting. This paper analyzed the brain networks of healthy people and patients at different stages (EMCI, LMCI, and AD). The results showed that in global network properties, most differences only existed between healthy people and patients, and few were discovered between patients at different stages. However, nearly all subnetwork properties showed significant differences between patients at different stages. Moreover, the most interesting result was that we found two different functional evolving patterns of cortical networks in progression of AD, named ‘temperature inversion’ and “monotonous decline,” but not the same monotonous decline trend as the external functional assessment observed in the course of disease progression. We suppose that those subnetworks, showing the same functional evolving pattern in AD progression, may have something the same in work mechanism in nature. And the subnetworks with ‘temperature inversion’ evolving pattern may play a special role in the development of AD.
Li, X, Bond, PL, O’Moore, L, Wilkie, S, Hanzic, L, Johnson, I, Mueller, K, Yuan, Z & Jiang, G 2020, 'Increased Resistance of Nitrite-Admixed Concrete to Microbially Induced Corrosion in Real Sewers', Environmental Science & Technology, vol. 54, no. 4, pp. 2323-2333.
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Microbially induced concrete corrosion is a major deterioration process in sewers, causing a huge economic burden, and improved mitigating technologies are required. This study reports a novel and promising effective solution to attenuate the corrosion in sewers using calcium nitrite-admixed concrete. This strategy aims to suppress the development and activity of corrosion-inducing microorganisms with the antimicrobial free nitrous acid, which is generated in situ from calcium nitrite that is added to the concrete. Concrete coupons with calcium nitrite as an admixture were exposed in a sewer manhole, together with control coupons that had no nitrite admixture, for 18 months. The corrosion process was monitored by measuring the surface pH, corrosion product composition, concrete corrosion loss, and the microbial community on the corrosion layer. During the exposure, the corrosion loss of the admixed concrete coupons was 30% lower than that of the control coupons. The sulfide uptake rate of the admixed concrete was also 30% lower, leading to a higher surface pH (0.5-0.6 unit), in comparison to that of the control coupons. A negative correlation between the calcium nitrite admixture in concrete and the abundance of sulfide-oxidizing microorganisms was determined by DNA sequencing. The results obtained in this field study demonstrated that this novel use of calcium nitrite as an admixture in concrete is a promising strategy to mitigate the microbially induced corrosion in sewers.
Li, X, Chen, L, Ji, Y, Li, M, Dong, B, Qian, G, Zhou, J & Dai, X 2020, 'Effects of chemical pretreatments on microplastic extraction in sewage sludge and their physicochemical characteristics', Water Research, vol. 171, pp. 115379-115379.
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© 2019 Elsevier Ltd Sewage sludge is a primary pathway for microplastics (MPs) entering into terrestrial ecosystems. However, a standardized method to analyze MP in sludge is lacking due to its high organic matter. This study investigated the extraction efficiency of six MPs in five solid matrices, i.e. sewage sludge, cattle manure, soil, sediment and silicon dioxide. Results show lower extraction efficiency of 87.2% for MPs in sludge compared with that in other matrices, especially polyethylene terephthalate (PET) (only 27.8%). The possible reason was that the presence of extracellular polymeric substances within the sludge hinders the MPs to float. Therefore, five protocols, i.e. hydrogen peroxide (H2O2), Fenton, nitric acid (HNO3), hydrochloric acid (HCl) and sodium hydroxide (NaOH) were used to pretreat the sludge and optimize the MP extraction. The sludge pretreated by H2O2, Fenton and 1 M of acids had higher MP extraction efficiency than the raw sludge due to higher extraction of the PET. The MP extraction efficiency in the sludge first increased, and subsequently decreased with the soluble chemical oxygen demand (SCOD) content, implying that moderate dissolution of sludge organic matter is beneficial to the MP extraction. Quantitative analysis of the changes in the MP physicochemical characteristics after the pretreatments indicated that polyamide (PA) and PET are not resistant to acid and alkali treatment, respectively. Principal component analysis shows that the effect of pretreatments on the MPs follows a decreasing sequence: alkali > high concentration of acids > low concentration of acids > H2O2 and Fenton. Additionally, the susceptibility of the MPs to the pretreatments follows a decreasing sequence: PET, PA and polymethyl methacrylate (PMMA) > polystyrene (PS) > polyethylene (PE) and polypropylene (PP). The findings supply novel insights into the effect of chemical pretreatments on MP extraction in sewage sludge.
Li, X, Ji, M, Nghiem, LD, Zhao, Y, Liu, D, Yang, Y, Wang, Q, Trinh, QT, Vo, D-VN, Pham, VQ & Tran, NH 2020, 'A novel red mud adsorbent for phosphorus and diclofenac removal from wastewater', Journal of Molecular Liquids, vol. 303, pp. 112286-112286.
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© 2019 Elsevier B.V. The ubiquitous occurrence of nutrients (e.g. phosphorus) and micropollutants (e.g. pharmaceuticals and endocrine disrupting chemicals) in wastewater and urban stormwater runoff sources may cause adverse effects on aquatic ecosystems and human health. Therefore, the removal of these pollutants from wastewater, treated effluent, and urban stormwater runoff is critically needed. In this study, a novel modified red mud with polypyrrole (RM-PPy) was successfully synthesized with improved functional groups (–OH, –N=, –NH–, N+), specific area (SBET 102.24 m2/g), and mesopore structure (i.e. average pore diameter of 3.29 nm), which are assumed to enhance the adsorptive removal of diclofenac (DCF) and phosphorus (P) in aqueous solution. The measured maximum adsorption capacity of RM-PPy towards diclofenac (195 mg/g) in single adsorbate system was higher than that (115.7 mg/g) in the binary adsorbates system (i.e. in the presence of P), indicating that the presence of pollutants such as P in water hampered the adsorptive removal of DCF. The adsorption of DCF and P was largely dependent on solution pH values. Higher adsorptive removals of DCF and P were observed at acidic conditions (pH 2–5). Adsorption isotherm of DCF and P was better fitted to Freundlich model compared to Langmuir isotherm model, suggesting multilayer coverage. Adsorption of DCF onto RM-PPy might take place via anion exchange and electrostatic interactions. For P adsorption, apart from anion exchange and electrostatic interactions, the chemical precipitation via ligand exchange between P and hydroxyl (–OH) in RM-PPy can be considered as one of the main adsorption mechanisms. Further studies on the competitive adsorption of other anionic micropollutants at environmentally relevant concentrations (ng/L–μg/L) in water samples by RM-PPy are needed to evaluate the potential application of RM-PPy for the removal of other anionic micropollutants (i.e. antibiotics) in treated wastew...
Li, X, Kuang, Z, Zhang, J, Liu, X, Hu, J, Xu, Q, Wang, D, Liu, Y, Wang, Q, Yang, Q & Li, H 2020, 'Performance and Mechanism of Potassium Ferrate(VI) Enhancing Dark Fermentative Hydrogen Accumulation from Waste Activated Sludge', ACS Sustainable Chemistry & Engineering, vol. 8, no. 23, pp. 8681-8691.
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© 2020 American Chemical Society. Potassium ferrate (K2FeO4, PF), as a multifunctional green oxidant, has been used for oxidative degradation of pollutants and recovery of resources in sludge. However, its impact on the generation of hydrogen in anaerobic fermentation of waste activated sludge (WAS) is still unclear. The purpose of this work is to study the influence of PF on the dark fermentative hydrogen production. Experimental result suggested that as PF increased from 0 to 0.09 g/g of TSS (total suspended solids), the maximal hydrogen production increased from 1.47 to 8.35 mL/g VSS (volatile suspended solids). A further increase to 0.12 g/g of TSS resulted in a decrease in hydrogen yield. Mechanism studies revealed that that the addition of PF not only facilitated the disruption of sludge cell and extracellular polymeric substances (EPS) but also increased the proportion of biodegradable organics, providing more bioavailable organics for subsequent reactions involved in hydrogen accumulation. Although the activities of microorganisms relevant to dark fermentation were suppressed to a certain extent in the presence of PF, the induced suppression to hydrogen consumers was more severe. Microbial studies indicated that the relative abundances of hydrogen producers (such as Petrimonas and Proteiniborus) were augmented while hydrogen consumers (such as Methanosaeta and Methylocaldum) decreased in the presence of PF.
Li, Y, Wang, D, Yang, G, Yuan, X, Xu, Q, Yang, Q, Liu, Y, Wang, Q, Ni, B-J, Tang, W & Jiang, L 2020, 'Enhanced dewaterability of anaerobically digested sludge by in-situ free nitrous acid treatment', Water Research, vol. 169, pp. 115264-115264.
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As the protonated form of nitrite, free nitrous acid (FNA) is a renewable chemical that can be produced on site from the anaerobic digestion liquor by nitritation, and has been widely employed to improve the fermentation of waste activated sludge (WAS). However, it is not clear whether and how FNA improves the dewaterability of anaerobically digested sludge (ADS). This work therefore aims to provide such supports through comparing the dewaterability of ADS treated by nitrite at different concentrations (0-250 mg/L) under three pH values (5.5, 6.3, or 7.2). Environmental results showed that nitrite was completely denitrified within 12 h, and its addition improved the dewaterability of ADS in all the cases. The optimal normalized capillary suction time of 18.0 ± 0.4 s L/g VSS was obtained at nitrite 50 mg/L and pH 5.5 (equivalent of 0.35 mg/L FNA) in comparison with corresponding value of 23.2 ± 0.4 s L/g·VSS at pH 5.5 (equivalent of 0 mg/L FNA). Under this scenario, 80.5% ± 2.0% of water content was obtained in the FNA-treated sample after press filtration while the corresponding value was 88.5% ± 1.7% in the control. The mechanism investigations showed that FNA treatment reduced surface negative charge of ADS flocs and caused disruption of extracellular polymeric substances and release of intracellular substances, which enhanced the flocculability, hydrophobicity, and flowability, but decreased the bound water content, fractal dimension, and viscosity of ADS. Additionally, FNA treatment altered the secondary structure of proteins through destroying the hydrogen bond, which led to a loose structure of protein, benefiting the exposure of hydrophobic sites or groups in EPS proteins. The findings obtained deepen our understanding of FNA affecting sludge dewatering and provide strong supports to sustainable operation of wastewater treatment plants.
Li, Y, Zeng, X, Zhou, J, Liu, H, Gu, Y, Pan, Z, Zeng, Y & Zeng, Y 2020, 'Incorporation of disposed oil-contaminated soil in cement-based materials', Resources, Conservation and Recycling, vol. 160, pp. 104838-104838.
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© 2020 Elsevier B.V. To realize the win-win objective of environmental conservation and waste recycling, oil-contaminated soil was utilized as an additive in cement-based materials. The effect of diesel and engine oil and the corresponding oil-contaminated soil on cement-based materials were studied, including the heat release of cement hydration, rheological and flow properties, flexural and compressive strength, hydration products and oil leaching values. The results showed that oil-contaminated soil increased the heat release of hydration of unit mass cement and reduced rheological and flow properties of cement paste and mortars. However, when the dosage of oil-contaminated soil is about 4%, the optimum values of the flexural and compressive strength of mortar, in standard curing 7 and 28 days, were obtained. The leaching values of oil in the disposition satisfied the requirement of China standards. The results confirmed that utilizing an appropriate dosage of oil-contaminated soil in cement-based materials improved the flexural and compressive strength, which is stable to dispose of the waste. This shows that using disposed oil-contaminated soil in cement-based materials will serve as a cost-effective and environmental solution.
Li, Y, Zhu, Y, Wang, D, Yang, G, Pan, L, Wang, Q, Ni, B-J, Li, H, Yuan, X, Jiang, L & Tang, W 2020, 'Fe(II) catalyzing sodium percarbonate facilitates the dewaterability of waste activated sludge: Performance, mechanism, and implication', Water Research, vol. 174, pp. 115626-115626.
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In this work, Fe(II) catalyzing sodium percarbonate (Fe(II)/SPC) was managed to facilitate waste activated sludge (WAS) dewatering for the first time. The results showed that after WAS was treated by 20 mg/g total suspended solids (TSS) Fe(II) and 50 mg/g TSS SPC, the water content of sludge cake (WCSC) by press filtration and capillary suction time (CST) dropped from 90.8% ± 1.6% and 96.1 ± 4.0 s (the control) to 55.6% ± 1.4% and 30.1 ± 2.5 s, respectively. The mechanism investigations indicated that four intermediates or products (i.e., •OH, H2O2, Fe(II), and Fe(III)) generated in the Fe(II)/SPC process were responsible for the improved WAS dewaterability, and •OH and Fe(III) were the two major contributors. It was found that •OH collapsed and fragmented extracellular polymeric substances, damaged cell wall and permeabilized cytoplasmic membrane, and transformed conformation of the extracellular proteins secondary structure via both affecting the hydrogen bond maintaining α-helix and cracking disulfide bond in cysteine residues while Fe(III), the oxidization product of Fe(II), decreased the surface electronegativity and water-affinity surface areas of WAS flocs. As a result, the bound water release, flocculability, surface hydrophobicity, drain capability, and flowability of WAS flocs were strengthened whereas the compact surface structure, colloidal forces, network strength, gel-like structure, and apparent viscosity of WAS flocs were weakened. In addition, Fe(II)/SPC process also reduced the recalcitrant organics and fecal coliforms in sludge, which facilitated land application of dewatered sludge. The findings acquired in this work not only deepens our understanding of Fe(II)/SPC-involved WAS treatment process but also may guide engineers to develop both effective and promising strategies to better condition WAS for dewatering in the future.
Lim, S, Akther, N, Tran, VH, Bae, T-H, Phuntsho, S, Merenda, A, Dumée, LF & Shon, HK 2020, 'Covalent organic framework incorporated outer-selective hollow fiber thin-film nanocomposite membranes for osmotically driven desalination', Desalination, vol. 485, pp. 114461-114461.
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Lim, S, Park, KH, Tran, VH, Akther, N, Phuntsho, S, Choi, JY & Shon, HK 2020, 'Size-controlled graphene oxide for highly permeable and fouling-resistant outer-selective hollow fiber thin-film composite membranes for forward osmosis', Journal of Membrane Science, vol. 609, pp. 118171-118171.
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© 2020 Elsevier B.V. Size-controlled graphene oxide (SGO) nanosheets, which are uniform and smaller in size than 2 μm, were successfully incorporated into a polyamide (PA) layer for preparing an outer-selective hollow fiber (OSHF) thin-film nanocomposite (TFN) membrane for forward osmosis (FO) applications by vacuum-assisted interfacial polymerization (VAIP). Here, we specifically demonstrate that the SGO nanosheets in amine aqueous solution were horizontally aligned and stacked on the surface of a membrane substrate by vacuum suction from outside to inside in the VAIP; the SGO nanosheets were then well-incorporated into the thin PA layer with less physical damage. In addition, the SGO nanosheets' effective loading inside the PA layer under the VAIP was much higher than that under the typical interfacial polymerization (IP), since there is no issue about the particle loss from air or nitrogen blowing to remove excess amine solution. The benefit would be highly cost-effective in terms of the nanomaterial's use in a TFN membrane production. As a result, the optimum OSHF TFN membrane incorporated with SGO at 0.0005 wt% (SGO5) exhibited outstanding FO performance, including higher water flux at 39.0 L m-2 h-1 and lower specific reverse solute flux at 0.16 g L-1, using a 1 M NaCl draw solution. Furthermore, this study demonstrates the effect of graphene oxide (GO)'s lateral size toward the short water pathway, and GO's stable incorporation and hydrophilicity of the PA thin film. In the fouling test using artificial wastewater, SGO-incorporated membranes exhibited enhanced fouling resistance and cleaning efficiency against the foulant-rich solution. This novel TFN membrane is therefore a good candidate to address FO's challenges for wastewater treatment or desalination.
Liu, M, Lu, X, Nothling, MD, Doherty, CM, Zu, L, Hart, JN, Webley, PA, Jin, J, Fu, Q & Qiao, GG 2020, 'Physical Aging Investigations of a Spirobisindane-Locked Polymer of Intrinsic Microporosity', ACS Materials Letters, vol. 2, no. 8, pp. 993-998.
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Polymers of intrinsic microporosity (PIMs) have exceptional gas separation performance for a broad range of applications. However, PIMs are highly susceptible to physical aging, which drastically reduces their long-term performance over time. In this work, we leverage complementary experimental and density functional theory (DFT) studies to decipher the inter-/intrachain changes that occur during aging of the prototypical PIM-1 and its rigidified analogue PIM-C1. By elucidating this hereto unexplored aging behavior, we reveal that the dramatic decrease in gas permeability of PIM materials during aging stems from a loss of fractional free volume (FFV) due to PIM chain relaxations induced by π-πinteractions, hydrogen bonding, or van der Waals' forces. While the PIM-1 based membranes displayed enhanced gas pair selectivities after aging, the PIM-C1 based membranes showed an opposite trend with unexpected reductions for CO2/N2 and CO2/CH4. This is due to the reductions in CO2/N2 and CO2/CH4 solubility (S) selectivities and, unlike PIM-1, the spirobisindane locked PIM-C1 (i.e., maintenance of micropore sizes) has a stable diffusivity (D) selectivities that cannot offset such reductions. These fundamental insights into the intrinsic relaxation of different PIM polymer chains during physical aging can guide the future design of high-performance PIM materials with enhanced anti-aging properties.
Liu, M, Nothling, MD, Tan, SSL, Webley, PA, Qiao, GG & Fu, Q 2020, 'Polyrotaxane-based thin film composite membranes for enhanced nanofiltration performance', Separation and Purification Technology, vol. 246, pp. 116893-116893.
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© 2020 An urgent need exists for the development of advanced water purification technologies to meet the increasing global demand being placed on freshwater resources. Membrane-based separation technologies for size-selective contaminant removal represent a promising approach to achieve this goal. Here, a novel thin film composite nanofiltration membrane is prepared via interfacial polymerization of α-cyclodextrin on a commercially available polyacrylonitrile substrate. Subsequent in-situ inclusion complexation of alkyne-functionalized poly(ethylene glycol) (PEG) is then used to tune the polyrotaxane-based pores for size-dependent filtration. The resultant membrane shows excellent size-selective rejection rates for organic dye (e.g. rhodamine B, >99%) as well as heavy-metal ions (e.g. Co(II), >90%), while crucially maintaining high water permeance (e.g. H2O: 7.1 L h−1 m−2 bar−1). The facile and straightforward synthetic approach to the fabrication of polyrotaxane nanofiltration membranes, combined with their strong nanofiltration separation performance, holds significant promise for membrane-based water purification applications.
Liu, M, Nothling, MD, Webley, PA, Jin, J, Fu, Q & Qiao, GG 2020, 'High-throughput CO2 capture using PIM-1@MOF based thin film composite membranes', Chemical Engineering Journal, vol. 396, pp. 125328-125328.
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© 2020 Elsevier B.V. Carbon capture from power plants represents a powerful technique to mitigate increasing greenhouse gas emissions. In this work, we describe a thin film composite (TFC) membrane incorporating a polymer of intrinsic microporosity (PIM-1) and metal organic framework (MOF) nanoparticles for post-combustion CO2 capture. The novel TFC membrane design consists of three layers: (1) a CO2 selective layer composed of a PIM-1@MOF mixed matrix; (2) an ultrapermeable PDMS gutter layer doped with MOF nanosheets; and (3) a porous polymeric substrate. Notably, the PDMS@MOF gutter layer incorporating amorphous nanosheets provides a CO2 permeance of 10,000–11,000 GPU, suggesting less gas transport resistance in comparison with pristine PDMS gutter layers. In addition, by blending nanosized MOF particles (MOF-74-Ni and NH2-UiO-66) into PIM-1 to afford a selective layer, the resultant TFC membrane assembly delivered improved CO2 permeance of 4660–7460 GPU and CO2/N2 selectivity of 26–33, compared with a pristine PIM-1 counterpart (CO2 permeance of 4320 GPU and CO2/N2 selectivity of 19). Furthermore, PIM-1@MOF based TFC membranes displayed an enhanced resistance to aging effect, maintaining a stable CO2 permeance of 900–1200 GPU and CO2/N2 selectivity of 26–30 after aging for 8 weeks. To the best of our knowledge, the high CO2 separation performance presented here is unprecedented for PIM-1 based TFC membranes reported in the open literature.
Liu, X, He, D, Wu, Y, Xu, Q, Wang, D, Yang, Q, Liu, Y, Ni, B-J, Wang, Q & Li, X 2020, 'Freezing in the presence of nitrite pretreatment enhances hydrogen production from dark fermentation of waste activated sludge', Journal of Cleaner Production, vol. 248, pp. 119305-119305.
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© 2019 Elsevier Ltd Due to the poor biodegradability of released organics and the rapid consumption of hydrogen, hydrogen production from the untreated waste activated sludge (WAS) and/or inocula is still limited. In this study, it was found that the dark fermentative hydrogen production was largely enhanced from WAS pretreated by freezing in the presence of nitrite. With an increase of nitrite addition from 100 to 400 mg NO2−-N/L during freezing pretreatment (−5 °C for 4 h), the maximal hydrogen yield increased from 7.96 to 19.40 mL/g VS (volatile solids), which was 5.5–13.4 times of that in the control (without freezing and nitrite addition). Mechanism explorations revealed that the proposed pretreatment not only accelerated the disintegration of sludge but also promoted the proportion of biodegradable organics released, thereby provided more bio-available substrates for subsequent hydrogen production. Proposed pretreatment severely suppressed the sludge microorganisms responding to homoacetogenesis (−32.1%), methanogenesis (−58.4%), and sulfate-reducing process (−51.5%), inhibited the consumption of hydrogen. Moreover, there was more acetic and butyric (76% versus 57.5%) but less propionic acid (22.6% versus 13.4%) in this pretreated fermenter, which was in correspondence with the theory of fermentation type affecting hydrogen production. Long-term fermentation experiments indicated that the proposed pretreatment boosted the [FeFe]-hydrogenase activities while suppressed the activities of carbon monoxide dehydrogenase, coenzyme F420, and adenylyl sulfate reductase.
Liu, X, Huang, X, Wu, Y, Xu, Q, Du, M, Wang, D, Yang, Q, Liu, Y, Ni, B-J, Yang, G, Yang, F & Wang, Q 2020, 'Activation of nitrite by freezing process for anaerobic digestion enhancement of waste activated sludge: Performance and mechanisms', Chemical Engineering Journal, vol. 387, pp. 124147-124147.
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© 2020 Elsevier B.V. Nitrite-based pretreatment was demonstrated to effectively improve anaerobic digestion of waste activated sludge. It was found in this work that the freezing activated nitrite pretreatment could further enhance the performances. With the increase of nitrite addition from 0 to 600 mg NO2−-N/L during freezing process, the biochemical methane potential of pretreated-sludge gradually increased from 191.3 ± 8.0 to 233.2 ± 10.6 mL per gram volatile solid (VS), while only 178.6 ± 7.3 mL/g VS was obtained in the raw sludge. Mechanism explorations revealed that the freezing activated nitrite pretreatment remarkably facilitated the disintegration of sludge. Excitation emission matrix and fluorescence regional integration analyses further revealed that nitrite addition during freezing process promoted the proportion of biodegradable organics released, thereby providing more bio-available substrates for subsequent anaerobic digestion. Freezing condition induced reactive derivatives from nitrite (e.g., free nitrite acid, NO2[rad], N2O3) were assumed to be the major contributors to the enhanced sludge disintegration and recalcitrant organics (e.g., humic acid-like substances) degradation. It was also found that 600 mg NO2−-N/L addition activated by freezing pretreatment produced an anaerobically digested sludge with an improved dewaterability, as indicated by the decrease of the specific resistance to filterability and moisture content of dewatered cake. Moreover, 600 mg NO2−-N/L addition activated by freezing pretreatment and subsequent anaerobic digestion largely inactivated the pathogens to the levels below Class A biosolids requirements. Considering that nitrite can be in-situ produced in wastewater treatment plants through nitritation of the digestion liquid, this nitrite-based freezing process for sludge pretreatment was environmental-friendly and economically attractive.
Liu, X, Wei, W, Xu, J, Wang, D, Song, L & Ni, B-J 2020, 'Photochemical decomposition of perfluorochemicals in contaminated water', Water Research, vol. 186, pp. 116311-116311.
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Perfluorochemicals (PFCs) are a set of chemicals containing C-F bonds, which are concerned due to their bioaccumulation property, persistent and toxicological properties. Photocatalytic approaches have been widely studied for the effective removal of PFCs due to the mild operation conditions. This review aims to provide a comprehensive and up-to-date summary on the homogenous and heterogeneous photocatalytic processes for PFCs removal. Specifically, the homogenous photocatalytic methods for remediating PFCs are firstly discussed, including generation of hydrated electrons (eaq‒) and its performance and mechanisms for photo-reductive destruction of PFCs, the active species responsible for photo-oxidative degradation of PFCs and the corresponding mechanisms, and metal-ion-mediated (Fe(III) mainly used) processes for the remediation of PFCs. The influences of molecular structures of PFCs and water matrix, such as dissolved oxygen, humic acid, nitrate, chloride on the homogenous photocatalytic degradation of PFCs are also discussed. For heterogeneous photocatalytic processes, various semiconductor photocatalysts used for the decomposition of perfluorooctanoic acid (PFOA) are then discussed in terms of their specific properties benefiting photocatalytic performances. The preparation methods for optimizing the performance of photocatalysts are also overviewed. Moreover, the photo-oxidative and photo-reductive pathways are summarized for remediating PFOA in the presences of different semiconductor photocatalysts, including active species responsible for the degradation. We finally put forward several key perspectives for the photocatalytic removal of PFCs to promote its practical application in PFCs-containing wastewater treatment, including the treatment of PFCs degradation products such as fluoride ion, and the development of noble-metal free photocatalysts that could efficiently remove PFCs under solar light irradiation.
Liu, Y, Li, H-W & Huang, Z 2020, 'Editorial: Metal Hydride-Based Energy Storage and Conversion Materials', Frontiers in Chemistry, vol. 8, p. 675.
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Liu, Y, Luo, G, Ngo, HH, Guo, W & Zhang, S 2020, 'Advances in thermostable laccase and its current application in lignin-first biorefinery: A review', Bioresource Technology, vol. 298, pp. 122511-122511.
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© 2019 Elsevier Ltd As the most abundant aromatic polymers on the Earth, lignin has great potential to produce biofuels and aromatic chemicals due to their high carbon content and low oxygen content. Lignin-first biorefinery methods have attracted increasing attention recently for their high-value of aromatic chemicals, and high biofuels productivity from lignocellulosic wastes. Thermostable laccase has proven to be an excellent alternative catalyst in degrading lignin for its versatile catalytic abilities under industrial conditions and pollution-free by-products. Thermostable laccases can be found in native extreme environments or modified by biologically based technologies such as gene recombination expression and enzyme direct evolution. This review demonstrated thermostable laccases and their application in lignin degradation. Future research should focus more on the investigation of the reaction of thermostable laccases with lignin substrates.
Liu, Y, Ngo, HH, Guo, W, Wang, D, Peng, L, Wei, W & Ni, B-J 2020, 'Impact of coexistence of sludge flocs on nitrous oxide production in a granule-based nitrification system: A model-based evaluation', Water Research, vol. 170, pp. 115312-115312.
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© 2019 Elsevier Ltd A common operational status of granule-based reactor is the inevitable coexistence of sludge flocs. Such hybrid system could have a profound impact on nitrous oxide (N2O) production in nitrifying process. In this work, a mathematical model is employed to evaluate the key role of the coexistence of sludge flocs on N2O production in a granule-based nitrifying system for the first time, by considering both nitrifier denitrification and hydroxylamine oxidation pathways. The modelling results show that the N2O production gradually decreases with the increase of the percentage of sludge flocs in the total biomass (10–60%). More N2O is tended to be generated in sludge flocs which has lower N2O production capacity compared to granular biomass, thus lowering the total N2O production. The relative contributions of two N2O production pathways are only affected by bulk dissolved oxygen (DO) for the sludge flocs in the hybrid system, whereas those are affected by both bulk DO and the fractions of sludge flocs for the granular biomass. The results reveal a substantial effect of the coexistence of sludge flocs on N2O production in granule-based nitrifying process, which should not be ignored in future design and operation.
Liu, Y, Zhao, T, Su, Z, Zhu, T & Ni, B-J 2020, 'Evaluating the roles of coexistence of sludge flocs on nitrogen removal and nitrous oxide production in a granule-based autotrophic nitrogen removal system', Science of The Total Environment, vol. 730, pp. 139018-139018.
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Certain levels of sludge flocs would always coexist in granule-based reactors due to the biomass detachment from granules. Such inevitable coexistence could affect both total nitrogen (TN) removal and nitrous oxide (N2O) production in autotrophic nitrogen removal systems. This work utilized a mathematical approach to systematically study the influence of the coexisting sludge flocs on TN removal and N2O production in a granular nitritation-anaerobic ammonium oxidation (Anammox) process for the first time, based on a 2-pathway N2O production model concept. The modelling results reveal that the highest TN removal efficiency decreases from ca. 87-88% to ca. 41-49% as the fraction of sludge flocs in the system increases from 10% to 40%, while the N2O production rate gradually increases with such increase. Meanwhile, both bulk dissolved oxygen (DO, 0.05-0.3 mg/L) and the size of granule (200-400 μm) could also influence the TN removal efficiency and N2O production. As the fraction of sludge flocs increases from 10% to 40%, the contribution of granular biomass to total N2O production is reduced due to increase of N2O-producing ammonia-oxidizing bacteria (AOB) in the sludge flocs, and the increase of granule size could intensify such decrease. In addition, the hydroxylamine oxidation pathway dominates the nitrifier denitrification pathway in both granules and sludge flocs under various testing conditions, whereas the increasing contribution of the latter would occur at a certain DO range, higher fraction of sludge flocs and smaller granule size. These results disclose an important influence of the coexisting sludge flocs on the performance of granular nitritation-Anammox systems.
Loganathan, P, Gradzielski, M, Bustamante, H & Vigneswaran, S 2020, 'Progress, challenges, and opportunities in enhancing NOM flocculation using chemically modified chitosan: a review towards future development', Environmental Science: Water Research & Technology, vol. 6, no. 1, pp. 45-61.
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Natural organic matter (NOM) occurs ubiquitously in water bodies and this can greatly affect feed or raw water quality (taste, colour, odour, bacterial growth). Chemically modified chitosan can effectively remove NOM by the flocculation process.
Logeswaran, J, Shamsuddin, AH, Silitonga, AS & Mahlia, TMI 2020, 'Prospect of using rice straw for power generation: a review', Environmental Science and Pollution Research, vol. 27, no. 21, pp. 25956-25969.
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With the ever-increasing energy demands, fossil fuels are gradually depleting and eventually, these nonrenewable sources of energy will be exhausted. Hence, there is an urgent need to formulate alternative fuels that are both renewable and sustainable. Biomass is one of the reliable sources of energy because it is replenishable. Rice is the staple food in many countries, particularly in Asia. The number of paddy fields has increased tremendously over the years and is expected to increase in the future in response to the growing world population. This will lead to significant amounts of agricultural wastes annually, particularly rice straw. In some countries, open burning and soil incorporation are used to manage agricultural wastes. Open burning is the preferred method because it is inexpensive. However, this method is highly undesirable because of its detrimental impact on the environment resulting from the release of carbon dioxide and methane gas. Hence, it is important to develop an energy-harvesting method from rice straw for power generation. More studies need to be carried out on the availability and characteristics of rice straw as well as logistic analysis to assess the potential of rice straw for power generation. This paper is focused on reviewing studies pertaining to the characteristics and potential of rice straw for power generation, current rice straw management practices, and logistic analysis in order to develop a suitable energy-harvesting method from rice straw in Malaysia.
Long, G, Xie, Y, Luo, Z, Qu, L, Zhou, JL & Li, W 2020, 'Deterioration mechanism of steam-cured concrete subjected to coupled environmental acid and drying action', Journal of Infrastructure Preservation and Resilience, vol. 1, no. 1, p. 5.
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AbstractIn order to investigate the deterioration mechanism of steam-cured concrete under severe environmental actions such as acid rain corrosion, salt corrosion, and cyclic thermal loading, accelerated corrosion tests were conducted in this study. Surface damage as well as deteriorative kinetics of steam-cured concrete and cement paste suffering from coupled acid-thermal actions was investigated by soaking-drying cycle experiments. The effects of mineral admixture, curing regime and corrosion condition on the durability were all comparatively studied, and the X-ray diffractograms and nanoindentation were applied to analyse the mechanism of corrosion deterioration. The results revealed that compared with the cementitious materials under standard curing, larger depth and faster corrosion were observed for steam-cured concrete and cement paste, which might be partly attributed to the lower content of hydrated production presented in steam-cured specimens. Besides, under acid solution soaking-drying cycle regime, there was significant higher corrosion depth compared to only soaking in acid solution. The corrosion depth under steam curing and soaking-drying condition increased by 156.68% and 44.17%, respectively, compared with those under standard curing and only soaking treatment. In addition, fly ash effectively decreased the corrosion depth of steam-cured cement paste and concrete by 64.98% and 16.33%, respectively.
Ly, QV, Matindi, C, Kuvarega, AT, Ngo, HH, Le, QV, Nam, VH & Li, J 2020, 'Exploring the novel PES/malachite mixed matrix membrane to remove organic matter for water purification', Chemical Engineering Research and Design, vol. 160, pp. 63-73.
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Lyu, H, Dong, Z, Roobavannan, M, Kandasamy, J & Pande, S 2020, 'Prospects of interventions to alleviate rural–urban migration in Jiangsu Province, China based on sensitivity and scenario analysis', Hydrological Sciences Journal, vol. 65, no. 13, pp. 2175-2184.
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© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Rural–urban migration is an adaptive response to location-specific environmental or socio-economic stressors. Jiangsu Province, China is witnessing rapid economic growth fuelled by manufacturing and services sector. Rural–urban migration in Jiangsu, which brings higher stress to resource-carrying capacity of urban areas, is driven by rural “push” factors, principally labour surplus and unemployment in agriculture. This study investigates possible policy interventions aimed at relieving the rapid rural–urban migration in Jiangsu based on a sensitivity analysis of driving factors in rural agricultural production. It shows that rural–urban migration is sensitive to input elasticities of precipitation and labour. Two groups of scenario analysis corresponding to possible policy interventions are implemented. The first policy focuses on providing government subsidies to rural non-agricultural industries then compensate for the shrinking agricultural production. Another policy supports education in rural areas to provide more skilled labour resource which can be absorbed by non-agricultural industries. Both two policies are effective in reducing rural unemployment and alleviating rural–urban migration.
Ma, XY, Dong, K, Tang, L, Wang, Y, Wang, XC, Ngo, HH, Chen, R & Wang, N 2020, 'Investigation and assessment of micropollutants and associated biological effects in wastewater treatment processes', Journal of Environmental Sciences, vol. 94, pp. 119-127.
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Currently, the wastewater treatment plants (WWTPs) attempt to achieve the shifting from general pollution parameters control to reduction of organic micropollutants discharge. However, they have not been able to satisfy the increasing ecological safety needs. In this study, the removal of micropollutants was investigated, and the ecological safety was assessed for a local WWTP. Although the total concentration of 31 micropollutants detected was reduced by 83% using the traditional biological treatment processes, the results did not reflect chemicals that had poor removal efficiencies and low concentrations. Of the five categories of micropollutants, herbicides, insecticides, and bactericides were difficult to remove, pharmaceuticals and UV filters were effectively eliminated. The specific photosynthesis inhibition effect and non-specific bioluminescence inhibition effect from wastewater were detected and evaluated using hazardous concentration where 5% of aquatic organisms are affected. The photosynthesis inhibition effect from wastewater in the WWTP was negligible, even the untreated raw wastewater. However, the bioluminescence inhibition effect from wastewater which was defined as the priority biological effect, posed potential ecological risk. To decrease non-specific biological effects, especially of macromolecular dissolved organic matter, overall pollutant reduction strategy is necessary. Meanwhile, the ozonation process was used to further decrease the bioluminescence inhibition effects from the secondary effluent; ≥ 0.34 g O3/g DOC of ozone dose was recommended for micropollutants elimination control and ecological safety.
Mahlia, TMI, Syazmi, ZAHS, Mofijur, M, Abas, AEP, Bilad, MR, Ong, HC & Silitonga, AS 2020, 'Patent landscape review on biodiesel production: Technology updates', Renewable and Sustainable Energy Reviews, vol. 118, pp. 109526-109526.
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© 2019 Elsevier Ltd Biodiesel is a renewable fuel made from vegetable oils and animal fats. Compared with fossil fuels, it has the potential to alleviate environmental pressures and achieve sustainable development. In this paper, 1660 patents related to biodiesel production were reviewed. They were published between January 1999 and July 2018 and were retrieved from the Derwent Innovation patent database. The patents were grouped into five categories depending on whether they related to starting materials, pre-treatment methods, catalysts, reactors and processing methods, or testing methods. Their analysis shows that the availability of biodiesel starting materials depends on climate, geographical location, local soil conditions, and local agricultural practices. Starting materials constitute 75% of overall production costs and, therefore, it is crucial to select the best feedstock. Pre-treatment of feedstock can improve its suitability for processing and increase extraction effectiveness and oil yield. Catalysts can enhance the solubility of alcohol, leading to higher reaction rates, faster biodiesel production processes, and lower biodiesel production costs. Moreover, the apparatus and processes used strongly affect the oil yield and quality, and production cost. In order to be commercialized and marketed, biodiesel should pass either the American Society for Testing and Materials (ASTM) standards or European Standards (EN). Due to increases in environmental awareness, it is likely that the number of published patents on biodiesel production will remain stable or even increase.
Mannina, G, Ni, B-J, Ferreira Rebouças, T, Cosenza, A & Olsson, G 2020, 'Minimizing membrane bioreactor environmental footprint by multiple objective optimization', Bioresource Technology, vol. 302, pp. 122824-122824.
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This paper presents a modelling study aimed at minimizing the environmental foot print of a membrane bioreactor (MBR) for wastewater treatment. Specifically, an integrated model for MBR was employed in view of the management optimization of an MBR biological nutrient removal (BNR) pilot plant in terms of operational costs and direct greenhouse gases emissions. The influence of the operational parameters (OPs) on performance indicators (PIs) was investigated by adopting the Extended-FAST sensitivity analysis method. Further, a multi-objective analysis was performed by applying the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The results show-up that the sludge retention time is the OP mostly affecting all the investigated PIs. By applying the set of optimal OPs, there was a reduction of 48% and 10% of the operational costs and direct emissions, respectively.
McCauley, JI, Labeeuw, L, Jaramillo-Madrid, AC, Nguyen, LN, Nghiem, LD, Chaves, AV & Ralph, PJ 2020, 'Management of Enteric Methanogenesis in Ruminants by Algal-Derived Feed Additives', Current Pollution Reports, vol. 6, no. 3, pp. 188-205.
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© 2020, Springer Nature Switzerland AG. Purpose of Review: In this paper, we critically review the current state of nutritional management strategies to reduce methane emissions resulting from enteric fermentation in livestock production. In this context, it highlights the novel strategy regarding the use of macroalgal- and microalgal-derived feed additives. Recent Findings: Several feed management strategies for ruminants focus on the inclusion of nutritional supplements, increasing proportion of starch, or supplementation with high-energy lipids. These strategies aim to improve animal productivity, whilst at the same time reduce methane emissions. Algae supplements are currently investigated as novel ingredients for decreasing methanogenesis, with the potential production of algal biomass also contributing to reducing greenhouse gas emissions. Thus, utilisation of algal biomass as a feed concentrate in dietary supplementation presents a sustainable and environmentally friendly strategy. Summary: This review summarises the current stage of research on dietary strategies and their influences on the metabolic processes during enteric fermentation. This information is essential for developing strategies to mitigate methane emissions in the livestock industry. We specifically present the opportunities that algae could offer as a feed additive for methanogenic reduction in cattle. The data compiled from the peer-reviewed literature revealed synergistic effects of algal biomass on methane reduction and animal productivity. However, the challenges regarding the mass cultivation of macro- and microalgae were noticed. Considering the diversity of algal species, future research should increase screening efforts to include more species and dosage evaluation, along with efforts to see if such effects are sustained over time.
Meena, NK, Nimbalkar, S, Fatahi, B & Yang, G 2020, 'Effects of soil arching on behavior of pile-supported railway embankment: 2D FEM approach', Computers and Geotechnics, vol. 123, pp. 103601-103601.
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Messer, LF, Ostrowski, M, Doblin, MA, Petrou, K, Baird, ME, Ingleton, T, Bissett, A, Van de Kamp, J, Nelson, T, Paulsen, I, Bodrossy, L, Fuhrman, JA, Seymour, JR & Brown, MV 2020, 'Microbial tropicalization driven by a strengthening western ocean boundary current', Global Change Biology, vol. 26, no. 10, pp. 5613-5629.
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AbstractWestern boundary currents (WBCs) redistribute heat and oligotrophic seawater from the tropics to temperate latitudes, with several displaying substantial climate change‐driven intensification over the last century. Strengthening WBCs have been implicated in the poleward range expansion of marine macroflora and fauna, however, the impacts on the structure and function of temperate microbial communities are largely unknown. Here we show that the major subtropical WBC of the South Pacific Ocean, the East Australian Current (EAC), transports microbial assemblages that maintain tropical and oligotrophic (k‐strategist) signatures, to seasonally displace more copiotrophic (r‐strategist) temperate microbial populations within temperate latitudes of the Tasman Sea. We identified specific characteristics of EAC microbial assemblages compared with non‐EAC assemblages, including strain transitions within the SAR11 clade, enrichment of Prochlorococcus, predicted smaller genome sizes and shifts in the importance of several functional genes, including those associated with cyanobacterial photosynthesis, secondary metabolism and fatty acid and lipid transport. At a temperate time‐series site in the Tasman Sea, we observed significant reductions in standing stocks of total carbon and chlorophyll a, and a shift towards smaller phytoplankton and carnivorous copepods, associated with the seasonal impact of the EAC microbial assemblage. In light of the substantial shifts in microbial assemblage structure and function associated with the EAC, we conclude that climate‐driven expansions of WBCs will expand the range of tropical oligotrophic microbes, and potentially profoundly impact the trophic status of temperate waters.
Miller, AD, Coleman, MA, Clark, J, Cook, R, Naga, Z, Doblin, MA, Hoffmann, AA, Sherman, CDH & Bellgrove, A 2020, 'Local thermal adaptation and limited gene flow constrain future climate responses of a marine ecosystem engineer', Evolutionary Applications, vol. 13, no. 5, pp. 918-934.
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AbstractRising ocean temperatures and extreme temperature events have precipitated declines and local extinctions in many marine species globally, but patterns of loss are often uneven across species ranges for reasons that are poorly understood. Knowledge of the extent of local adaptation and gene flow may explain such patterns and help predict future trajectories under scenarios of climate change. We test the extent to which local differentiation in thermal tolerance is influenced by gene flow and local adaptation using a widely distributed intertidal seaweed (Hormosira banksii) from temperate Australia. Population surveys across ~2,000 km of the species range revealed strong genetic structuring at regional and local scales (global FST = 0.243) reflecting extremely limited gene flow, while common garden experiments (14‐day exposures to 15, 18, 21°C) revealed strong site differences in early development and mortality in response to elevated temperature. Embryos from many sites spanning a longitudinal thermal gradient showed suppressed development and increased mortality to elevated water temperatures, but populations originating from warmer and more variable thermal environments tended to be less susceptible to warming. Notably, there was significant local‐scale variation in the thermal responses of embryos within regions which was corroborated by the finding of small‐scale genetic differences. We expect the observed genetic and phenotypic differentiation to lead to uneven responses to warming sea surface temperatures in this important marine foundation species. The study highlights the challenges of predicting species responses to thermal stress and the importance of management strategies that incorporate evolutionary potential for “climate‐proofing” marine ecosystems.
Mishra, B, Varjani, S, Agrawal, DC, Mandal, SK, Ngo, HH, Taherzadeh, MJ, Chang, J-S, You, S & Guo, W 2020, 'Engineering biocatalytic material for the remediation of pollutants: A comprehensive review', Environmental Technology & Innovation, vol. 20, pp. 101063-101063.
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Mishra, B, Varjani, S, Pradhan, I, Ekambaram, N, Teixeira, JA, Ngo, HH & Guo, W 2020, 'Insights into Interdisciplinary Approaches for Bioremediation of Organic Pollutants: Innovations, Challenges and Perspectives', Proceedings of the National Academy of Sciences, India Section B: Biological Sciences, vol. 90, no. 5, pp. 951-958.
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© 2020, The National Academy of Sciences, India. Modern industrialization has originated a tremendous industrial growth. Discharge of industrial effluent is a critical threat to a safe environment. Removal of various pollutants from industrial wastewater is obligatory for controlling environmental pollution. Bioremediation using biotechnological interventions has attracted greater attention among the researchers in the field of control and abatement of environmental pollution. This review is aimed to introduce methods for bioremediation on the removal of organic pollutants from industrial wastewater that have been discussed, and the kinetic models that are related to it have been introduced. In addition, biotechnological interventions on bioremediation of pollutants have been discussed fingerprinting of microbial sp. present at polluted sites. Microbial electrochemical technologies such as a green technology for the removal of pollutants from industrial effluents and simultaneous resource recovery from industrial waste have been discussed to generate up-to-date scientific literature. This review also provides detailed knowledge gaps, challenges and research perspectives related to the topic.
Mofijur, M, Kusumo, F, Fattah, IMR, Mahmudul, HM, Rasul, MG, Shamsuddin, AH & Mahlia, TMI 2020, 'Resource Recovery from Waste Coffee Grounds Using Ultrasonic-Assisted Technology for Bioenergy Production', Energies, vol. 13, no. 7, pp. 1770-1770.
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Biodiesel is a proven alternative fuel that can serve as a substitute for petroleum diesel due to its renewability, non-toxicity, sulphur-free nature and superior lubricity. Waste-based non-edible oils are studied as potential biodiesel feedstocks owing to the focus on the valorisation of waste products. Instead of being treated as municipal waste, waste coffee grounds (WCG) can be utilised for oil extraction, thereby recovering an energy source in the form of biodiesel. This study evaluates oil extraction from WCG using ultrasonic and Soxhlet techniques, followed by biodiesel conversion using an ultrasonic-assisted transesterification process. It was found that n-hexane was the most effective solvent for the oil extraction process and ultrasonic-assisted technology offers a 13.5% higher yield compared to the conventional Soxhlet extraction process. Solid-to-solvent ratio and extraction time of the oil extraction process from the dried waste coffee grounds (DWCG) after the brewing process was optimised using the response surface methodology (RSM). The results showed that predicted yield of 17.75 wt. % of coffee oil can be obtained using 1:30 w/v of the mass ratio of DWCG-ton-hexane and 34 min of extraction time when 32% amplitude was used. The model was verified by the experiment where 17.23 wt. % yield of coffee oil was achieved when the extraction process was carried out under optimal conditions. The infrared absorption spectrum analysis of WCG oil determined suitable functional groups for biodiesel conversion which was further treated using an ultrasonic-assisted transesterification process to successfully convert to biodiesel.
Mofijur, M, Rizwanul Fattah, IM, Saiful Islam, ABM, Uddin, MN, Ashrafur Rahman, SM, Chowdhury, MA, Alam, MA & Uddin, MA 2020, 'Relationship between Weather Variables and New Daily COVID-19 Cases in Dhaka, Bangladesh', Sustainability, vol. 12, no. 20, pp. 8319-8319.
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The present study investigated the relationship between the transmission of COVID-19 infections and climate indicators in Dhaka, Bangladesh, using coronavirus infections data available from the Institute of Epidemiology, Disease Control and Research (IEDCR), Bangladesh. The Spearman rank correlation test was carried out to study the association of seven climate indicators, including humidity, air quality, minimum temperature, precipitation, maximum temperature, mean temperature, and wind speed with the COVID-19 outbreak in Dhaka, Bangladesh. The study found that, among the seven indicators, only two indicators (minimum temperature and average temperature) had a significant relationship with new COVID-19 cases. The study also found that air quality index (AQI) had a strong negative correlation with cumulative cases of COVID-19 in Dhaka city. The results of this paper will give health regulators and policymakers valuable information to lessen the COVID-19 spread in Dhaka and other countries around the world.
Mojiri, A, Zhou, J, Vakili, M & Van Le, H 2020, 'Removal performance and optimisation of pharmaceutical micropollutants from synthetic domestic wastewater by hybrid treatment', Journal of Contaminant Hydrology, vol. 235, pp. 103736-103736.
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Occurrence of pharmaceutical micropollutants in aquatic environments has been one amongst serious environmental problems. During this study, two reactors, including a sequencing batch reactor (SBR) + powdered composite adsorbent (CA) (first reactor, SBR + CA) and a sequencing batch reactor (second reactor, SBR), were designed to treat synthetic wastewater. Powdered CA was added with a dosage of 4.8 g L-1 to the first reactor. Tap water was contaminated with chemical oxygen demand (COD), ammonia and three pharmaceuticals, namely, atenolol (ATN), ciprofloxacin (CIP) and diazepam (DIA) to produce synthetic wastewater. The SBR + CA illustrated a better performance during synthetic municipal wastewater treatment. Up to 138.6 mg L-1 (92.4%) of COD and up to 114.2 mg L-1 (95.2%) of ammonia were removed by the first reactor. Moreover, optimisation of pharmaceuticals removal was conducted through response surface methodology (RSM) and artificial neural network (ANN). Based on the RSM, the best elimination of ATN (90.2%, 2.26 mg L-1), CIP (94.0%, 2.35 mg L-1) and DIA (95.5%, 2.39 mg L-1) was detected at the optimum initial concentration of MPs (2.51 mg L-1) and the contact time (15.8 h). In addition, ANN represented a high R2 value (>0.99) and a rational mean squared error (<1.0) during the optimisation of micropollutants removal by both reactors. Moreover, adsorption isotherm study showed that the Freundlich isotherm could justify the abatement of micropollutants by using CA better than the Langmuir isotherm.
Mojiri, A, Zhou, JL, Robinson, B, Ohashi, A, Ozaki, N, Kindaichi, T, Farraji, H & Vakili, M 2020, 'Pesticides in aquatic environments and their removal by adsorption methods', Chemosphere, vol. 253, pp. 126646-126646.
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Although pesticides are widely used in agriculture, industry and households, they pose a risk to human health and ecosystems. Based on target organisms, the main types of pesticides are herbicides, insecticides and fungicides, of which herbicides accounted for 46% of the total pesticide usage worldwide. The movement of pesticides into water bodies occurs through run-off, spray drift, leaching, and sub-surface drainage, all of which have negative impacts on aquatic environments and humans. We sought to define the critical factors affecting the fluxes of contaminants into receiving waters. We also aimed to specify the feasibility of using sorbents to remove pesticides from waterways. In Karun River in Iran (1.21 × 105 ng/L), pesticide concentrations are above regulatory limits. The concentration of pesticides in fish can reach 26.1 × 103 μg/kg, specifically methoxychlor herbicide in Perca fluviatilis in Lithuania. During the last years, research has focused on elimination of organic pollutants, such as pesticides, from aqueous solution. Pesticide adsorption onto low-cost materials can effectively remediate contaminated waters. In particular, nanoparticle adsorbents and carbon-based adsorbents exhibit high performance (nearly 100%) in removing pesticides from water bodies.
Moon, DH, Chung, WJ, Chang, SW, Lee, SM, Kim, SS, Jeung, JH, Ro, YH, Ahn, JY, Guo, W, Ngo, HH & Nguyen, DD 2020, 'Fabrication and characterization of Ni-Ce-Zr ternary disk-shaped catalyst and its application for low-temperature CO2 methanation', Fuel, vol. 260, pp. 116260-116260.
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Mujtaba, MA, Kalam, MA, Masjuki, HH, Gul, M, Soudagar, MEM, Ong, HC, Ahmed, W, Atabani, AE, Razzaq, L & Yusoff, M 2020, 'Comparative study of nanoparticles and alcoholic fuel additives-biodiesel-diesel blend for performance and emission improvements', Fuel, vol. 279, pp. 118434-118434.
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© 2020 Elsevier Ltd This study aims to investigate a CI diesel engine characteristic of diesel-biodiesel blend with oxygenated alcohols and nanoparticle fuel additives. Biodiesel was synthesized from a complementary palm-sesame oil blend using an ultrasound-assisted transesterification process. B30 was mixed with fuel additives as the base fuel to form ternary blends in different proportions before engine testing. The oxygenated alcohols (DMC and DEE) and nanoparticles (CNT and TiO2) were used to improve both the fuel characteristics and engine emission and performance parameters. B30 fuel was mixed with 5% (DEE) and 10% (DMC) by volume and 100 ppm concentration of CNT and TiO2 nanoparticles, respectively, which are kept constant during this study. Engine performance and emissions characteristics were studied using a CI diesel engine with variable engine rpm at full load condition. The results were compared with B30 fuel and B10 (commercial diesel). The main findings indicated that the B30 + TiO2 ternary blend shows an overall decrease in brake specific fuel consumption up to 4.1% among all tested fuels. B30 + DMC produced a higher 9.88% brake thermal efficiency, among other fuels. B30 + DMC ternary blend showed a maximum decrease in CO and HC emissions by 29.9% and 21.4%, respectively, collated to B30. B30 + CNT ternary blend showed a maximum reduction of 3.92% in NOx emissions compared to B30.
Mujtaba, MA, Masjuki, HH, Kalam, MA, Noor, F, Farooq, M, Ong, HC, Gul, M, Soudagar, MEM, Bashir, S, Rizwanul Fattah, IM & Razzaq, L 2020, 'Effect of Additivized Biodiesel Blends on Diesel Engine Performance, Emission, Tribological Characteristics, and Lubricant Tribology', Energies, vol. 13, no. 13, pp. 3375-3375.
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This research work focuses on investigating the lubricity and analyzing the engine characteristics of diesel–biodiesel blends with fuel additives (titanium dioxide (TiO2) and dimethyl carbonate (DMC)) and their effect on the tribological properties of a mineral lubricant. A blend of palm–sesame oil was used to produce biodiesel using ultrasound-assisted transesterification. B30 (30% biodiesel + 70% diesel) fuel was selected as the base fuel. The additives used in the current study to prepare ternary fuel blends were TiO2 and DMC. B30 + TiO2 showed a significant reduction of 6.72% in the coefficient of friction (COF) compared to B30. B10 (Malaysian commercial diesel) exhibited very poor lubricity and COF among all tested fuels. Both ternary fuel blends showed a promising reduction in wear rate. All contaminated lubricant samples showed an increment in COF due to the dilution of combustible fuels. Lub + B10 (lubricant + B10) showed the highest increment of 42.29% in COF among all contaminated lubricant samples. B30 + TiO2 showed the maximum reduction (6.76%) in brake-specific fuel consumption (BSFC). B30 + DMC showed the maximum increment (8.01%) in brake thermal efficiency (BTE). B30 + DMC exhibited a considerable decline of 32.09% and 25.4% in CO and HC emissions, respectively. The B30 + TiO2 fuel blend showed better lubricity and a significant improvement in engine characteristics.
Mujtaba, MA, Masjuki, HH, Kalam, MA, Ong, HC, Gul, M, Farooq, M, Soudagar, MEM, Ahmed, W, Harith, MH & Yusoff, MNAM 2020, 'Ultrasound-assisted process optimization and tribological characteristics of biodiesel from palm-sesame oil via response surface methodology and extreme learning machine - Cuckoo search', Renewable Energy, vol. 158, pp. 202-214.
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© 2020 Elsevier Ltd The purpose of this study was the improvement of cold flow and lubricity characteristics of biodiesel produced from the palm-sesame oil blend. Extreme learning machine (ELM) and response surface methodology (RSM) techniques were used to model the production process and the input variables (time, catalyst amount, methanol to oil ratio, and duty cycle) were optimized using cuckoo search algorithm. The mean absolute percentage error (MAPE), coefficient of determination (R2), mean square error (MSE), root mean square error (RMSE), and standard error of prediction (SEP) were calculated to evaluate the performance of RSM and ELM. The results showed that ELM model had better performance in prediction than RSM model. The optimum yield of P50S50 biodiesel obtained was 96.6138% under operating parameters of time (38.96 min), duty cycle (59.52%), methanol to oil ratio (60 V/V %) and catalyst amount (0.70 wt%). The cold flow characteristics of P50S50 biodiesel are significantly improved like cloud point (7.89 °C), pour point (3.80 °C), and cold filter plugging point (- 1.77 °C) with better oxidation stability 6.89 h. The average coefficient of friction P50S50 biodiesel was lower than palm biodiesel (B100) and B10 commercial diesel by 2.29% and 12.37% respectively.
Mujtaba, MA, Muk Cho, H, Masjuki, HH, Kalam, MA, Ong, HC, Gul, M, Harith, MH & Yusoff, MNAM 2020, 'Critical review on sesame seed oil and its methyl ester on cold flow and oxidation stability', Energy Reports, vol. 6, pp. 40-54.
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© 2019 The demand for renewable energy is steadily increasing due to rapid population growth and economic development worldwide. An additional reason is that fossil fuel reserves are limited, and this situation results in their non-uniform availability globally. Furthermore, the attitudes of the society, energy policies and technology choices are constantly changing. Thus, renewable energy resources are now considered good alternatives to fossil fuels. In the meantime, liquid energy, such as methyl ester from locally produced vegetable oils, is well accepted by many countries, even though it is currently being blended up to 20% with petroleum fuels. Recently, the industrialisation of biodiesel is a major problem because of its poor cold flow properties and oxidative stability. Vegetable oils are also being blended in an appropriate proportion before transesterification to obtain the desired properties in biodiesel. Similarly, poor cold flow properties and oxidative stability can be improved by choosing suitable vegetable oils for making blends. Amongst all available vegetable oils, sesame seed oil (SSO) has unique cold flow properties and oxidation stability, particularly because of naturally occurring antioxidants and preservatives, which enhance the stability of oil towards rancidity. Therefore, SSO can be used as a potential feedstock for blending with other vegetable oils to enhance the overall cold flow and oxidation stability properties. This overview summarises sesame cultivation, SSO production, the physicochemical properties of SSO and its potential as an alternative renewable fuel source. In this review, the physicochemical properties of sesame biodiesel are compared with those of biodiesel derived from other vegetable oils. Results show that blending SSO with palm oil before transesterification will successfully improve the cold flow properties and oxidation stability of palm methyl ester (biodiesel).
Muniyasamy, A, Sivaporul, G, Gopinath, A, Lakshmanan, R, Altaee, A, Achary, A & Velayudhaperumal Chellam, P 2020, 'Process development for the degradation of textile azo dyes (mono-, di-, poly-) by advanced oxidation process - Ozonation: Experimental & partial derivative modelling approach', Journal of Environmental Management, vol. 265, pp. 110397-110397.
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Murray, JS, Nishimura, T, Finch, SC, Rhodes, LL, Puddick, J, Harwood, DT, Larsson, ME, Doblin, MA, Leung, P, Yan, M, Rise, F, Wilkins, AL & Prinsep, MR 2020, 'The role of 44-methylgambierone in ciguatera fish poisoning: Acute toxicity, production by marine microalgae and its potential as a biomarker for Gambierdiscus spp.', Harmful Algae, vol. 97, pp. 101853-101853.
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Ciguatera fish poisoning (CFP) is prevalent around the tropical and sub-tropical latitudes of the world and impacts many Pacific island communities intrinsically linked to the reef system for sustenance and trade. While the genus Gambierdiscus has been linked with CFP, it is commonly found on tropical reef systems in microalgal assemblages with other genera of toxin-producing, epiphytic and/or benthic dinoflagellates - Amphidinium, Coolia, Fukuyoa, Ostreopsis and Prorocentrum. Identifying a biomarker compound that can be used for the early detection of Gambierdiscus blooms, specifically in a mixed microalgal community, is paramount in enabling the development of management and mitigation strategies. Following on from the recent structural elucidation of 44-methylgambierone, its potential to contribute to CFP intoxication events and applicability as a biomarker compound for Gambierdiscus spp. was investigated. The acute toxicity of this secondary metabolite was determined by intraperitoneal injection using mice, which showed it to be of low toxicity, with an LD50 between 20 and 38 mg kg-1. The production of 44-methylgambierone by 252 marine microalgal isolates consisting of 90 species from 32 genera across seven classes, was assessed by liquid chromatography-tandem mass spectrometry. It was discovered that the production of this secondary metabolite was ubiquitous to the eight Gambierdiscus species tested, however not all isolates of G. carpenteri, and some species/isolates of Coolia and Fukuyoa.
Naidu, G, Tijing, L, Johir, MAH, Shon, H & Vigneswaran, S 2020, 'Hybrid membrane distillation: Resource, nutrient and energy recovery', Journal of Membrane Science, vol. 599, pp. 117832-117832.
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© 2020 Elsevier B.V. Membrane distillation (MD) is a promising alternative thermal-based membrane process that can achieve high-quality freshwater across various impaired water sources. However, the performance of MD as a stand-alone system remains a challenge for attaining commercialization. Hybrid MD - the integration of MD with other processes, offers a practical approach for performance enhancement as well as the possibility to achieve valuable resource recovery. This review details the performance and related challenges of various hybrid MD systems with a focus on resource recovery. On the basis of recovering valuable salt/element from impaired water sources, hybrid MD-crystallizer is limited to the recovery of major salts. Comparatively, MD-adsorbent exhibits potential for selectively recovering valuable elements, which may offset treatment cost. Meanwhile, hybrid MD-bioreactor (MDBR) and MD-forward osmosis (MD-FO) are especially favorable combinations for attaining water reclamation from the wastewater industry and recovering nutrients and biogas that mitigates environmental pollution. Simultaneous recovery of water and energy can be attained with hybrid MD-pressure retarded osmosis (MD-PRO) and MD-reverse electrodialysis (MD-RED). Overall, this review highlights the favorable potential of hybrid MD for recovering resources in niche applications. Future suggestions for improving hybrid MD are discussed, specifically pilot-scale application, module configuration and membrane development.
Nakagawa, K, Uchida, K, Wu, JLC, Shintani, T, Yoshioka, T, Sasaki, Y, Fang, L-F, Kamio, E, Shon, HK & Matsuyama, H 2020, 'Fabrication of porous polyketone forward osmosis membranes modified with aromatic compounds: Improved pressure resistance and low structural parameter', Separation and Purification Technology, vol. 251, pp. 117400-117400.
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Nghiem, LD, Morgan, B, Donner, E & Short, MD 2020, 'The COVID-19 pandemic: Considerations for the waste and wastewater services sector', Case Studies in Chemical and Environmental Engineering, vol. 1, pp. 100006-100006.
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Ngoc, TP, Fatahi, B, Khabbaz, H & Sheng, D 2020, 'Impacts of matric suction equalization on small strain shear modulus of soils during air drying', Canadian Geotechnical Journal, vol. 57, no. 12, pp. 1982-1997.
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In this study, a weight-control bender element system has been developed to investigate the impact of matric suction equalization on the measurement of small strain shear modulus (Gmax) during an air-drying process. The setup employed is capable of measuring the shear wave velocity and the corresponding Gmax of the soil sample in either an open system in which the soil sample evaporates freely or in a closed system that allows the process of matric suction equalization. The comparison between measurements of Gmax in the open and closed systems revealed underestimations of Gmax when matric suction equalization was ignored due to the nonuniform distribution of water content across the sample cross-sectional area. This study also investigated the time required for matric suction equalization tse to be established for samples with different sizes. The experimental results indicated two main mechanisms driving the matric suction equalization in a closed system during an air-drying process, namely the hydraulic flow of water and the flow of vapour. While the former played the key role when the micropores were still saturated at the high range of water content, effects of the latter increased and finally dominated when more air invaded the micropores at lower water contents.
Nguyen, AQ, Nguyen, LN, Johir, MAH, Ngo, H-H, Chaves, AV & Nghiem, LD 2020, 'Derivation of volatile fatty acid from crop residues digestion using a rumen membrane bioreactor: A feasibility study', Bioresource Technology, vol. 312, pp. 123571-123571.
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Nguyen, HM, Kim, M, Ralph, PJ, Marín-Guirao, L, Pernice, M & Procaccini, G 2020, 'Stress Memory in Seagrasses: First Insight Into the Effects of Thermal Priming and the Role of Epigenetic Modifications', Frontiers in Plant Science, vol. 11, p. 494.
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While thermal priming and the relative role of epigenetic modifications have been widely studied in terrestrial plants, their roles remain unexplored in seagrasses so far. Here, we experimentally compared the ability of two different functional types of seagrass species, dominant in the Southern hemisphere, climax species Posidonia australis and pioneer species Zostera muelleri, to acquire thermal-stress memory to better survive successive stressful thermal events. To this end, a two-heatwave experimental design was conducted in a mesocosm setup. Findings across levels of biological organization including the molecular (gene expression), physiological (photosynthetic performances and pigments content) and organismal (growth) levels provided the first evidence of thermal priming in seagrasses. Non-preheated plants suffered a significant reduction in photosynthetic capacity, leaf growth and chlorophyll a content, while preheated plants were able to cope better with the recurrent stressful event. Gene expression results demonstrated significant regulation of methylation-related genes in response to thermal stress, suggesting that epigenetic modifications could play a central role in seagrass thermal stress memory. In addition, we revealed some interspecific differences in thermal responses between the two different functional types of seagrass species. These results provide the first insights into thermal priming and relative epigenetic modifications in seagrasses paving the way for more comprehensive forecasting and management of thermal stress in these marine foundation species in an era of rapid environmental change.
Nguyen, LN, Commault, AS, Kahlke, T, Ralph, PJ, Semblante, GU, Johir, MAH & Nghiem, LD 2020, 'Genome sequencing as a new window into the microbial community of membrane bioreactors – A critical review', Science of The Total Environment, vol. 704, pp. 135279-135279.
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Recent developed sequencing techniques have resulted in a new and unprecedented way to study biological wastewater treatment, in which most organisms are uncultivable. This review provides (i) an insight on state-of-the-art sequencing techniques and their limitations; (ii) a critical assessment of the microbial community in biological reactor and biofouling layer in a membrane bioreactor (MBR). The data from high-throughput sequencing has been used to infer microbial growth conditions and metabolisms of microorganisms present in MBRs at the time of sampling. These data shed new insight to two fundamental questions about a microbial community in the MBR process namely the microbial composition (who are they?) and the functions of each specific microbial assemblage (what are their function?). The results to date also highlight the complexity of the microbial community growing on MBRs. Environmental conditions are dynamic and diverse, and can influence the diversity and structural dynamics of any given microbial community for wastewater treatment. The benefits of understanding the structure of microbial communities on three major aspects of the MBR process (i.e. nutrient removal, biofouling control, and micropollutant removal) were symmetrically delineated. This review also indicates that the deployment of microbial community analysis for a practical engineering context, in terms of process design and system optimization, can be further realized.
Nguyen, LN, Truong, MV, Nguyen, AQ, Johir, MAH, Commault, AS, Ralph, PJ, Semblante, GU & Nghiem, LD 2020, 'A sequential membrane bioreactor followed by a membrane microalgal reactor for nutrient removal and algal biomass production', Environmental Science: Water Research & Technology, vol. 6, no. 1, pp. 189-196.
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A hybrid process combining a single compartment aerobic membrane bioreactor (MBR) and a membrane microalgal reactor (MMR) was evaluated for nutrient removal and microalgal biomass production.
Nguyen, LN, Vu, MT, Johir, MAH, Pathak, N, Zdarta, J, Jesionowski, T, Semblante, GU, Hai, FI, Khanh Dieu Nguyen, H & Nghiem, LD 2020, 'A Novel Approach in Crude Enzyme Laccase Production and Application in Emerging Contaminant Bioremediation', Processes, vol. 8, no. 6, pp. 648-648.
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Laccase enzyme from white-rot fungi is a potential biocatalyst for the oxidation of emerging contaminants (ECs), such as pesticides, pharmaceuticals and steroid hormones. This study aims to develop a three-step platform to treat ECs: (i) enzyme production, (ii) enzyme concentration and (iii) enzyme application. In the first step, solid culture and liquid culture were compared. The solid culture produced significantly more laccase than the liquid culture (447 vs. 74 µM/min after eight days), demonstrating that white rot fungi thrived on a solid medium. In the second step, the enzyme was concentrated 6.6 times using an ultrafiltration (UF) process, resulting in laccase activity of 2980 µM/min. No enzymatic loss due to filtration and membrane adsorption was observed, suggesting the feasibility of the UF membrane for enzyme concentration. In the third step, concentrated crude enzyme was applied in an enzymatic membrane reactor (EMR) to remove a diverse set of ECs (31 compounds in six groups). The EMR effectively removed of steroid hormones, phytoestrogen, ultraviolet (UV) filters and industrial chemical (above 90%). However, it had low removal of pesticides and pharmaceuticals.
Nguyen, NC, Duong, HC, Nguyen, HT, Chen, S-S, Le, HQ, Ngo, HH, Guo, W, Duong, CC, Le, NC & Bui, XT 2020, 'Forward osmosis–membrane distillation hybrid system for desalination using mixed trivalent draw solution', Journal of Membrane Science, vol. 603, pp. 118029-118029.
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Nguyen, TAH, Ngo, HH, Guo, WS, Nguyen, THH, Soda, S, Vu, ND, Bui, TKA, Vo, TDH, Bui, XT, Nguyen, TT & Pham, TT 2020, 'White hard clam (Meretrix lyrata) shells media to improve phosphorus removal in lab-scale horizontal sub-surface flow constructed wetlands: Performance, removal pathways, and lifespan', Bioresource Technology, vol. 312, pp. 123602-123602.
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This work examined the phosphorus (P) removal from the synthetic pretreated swine wastewater using lab-scale horizontal sub-surface flow constructed wetlands (HSSF-CWs). White hard clam (Meretrix lyrata) shells (WHC) and Paspalum atratum were utilized as substrate and plant, respectively. The focus was placed on treatment performance, removal mechanisms and lifespan of the HSSF-CWs. Results indicated that WHC-based HSSF-CW with P. atratum exhibited a high P removal (89.9%). The mean P efluent concentration and P removal rate were 1.34 ± 0.95 mg/L and 0.32 ± 0.03 g/m2/d, respectively. The mass balance study showed that media sorption was the dominant P removal pathway (77.5%), followed by microbial assimilation (14.5%), plant uptake (5.4%), and other processes (2.6%). It was estimated the WHC-based bed could work effectively for approximately 2.84 years. This WHC-based HSSF-CWs technology will therefore pave the way for recycling Ca-rich waste materials as media in HSSF-CWs to enhance P-rich wastewater purification.
Nguyen, TAH, Ngo, HH, Guo, WS, Nguyen, TT, Vu, ND, Soda, S, Nguyen, THH, Nguyen, MK, Tran, TVH, Dang, TT, Nguyen, VH & Cao, TH 2020, 'White hard clam (Meretrix lyrata) shells as novel filter media to augment the phosphorus removal from wastewater', Science of The Total Environment, vol. 741, pp. 140483-140483.
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It is well recognized that filter media play a crucial role in constructed wetlands (CWs) for decontamination of phosphorus (P)-rich wastewater. This study investigates the suitability of raw white hard clam shells (WHC) and white hard clam shells thermally modified at 800 °C (WHC-M800) as potential media to enhance P treatment performance in CWs. The results indicated that both WHC and WHC-M800 displayed appropriate physicochemical properties, such as high porosity, excellent hydraulic conductivity, and rich Ca content. WHC-M800 exhibited a superior P adsorption capacity (38.7 mg/g) to WHC (12.8 mg/g). However, the practical utilization of WHC-M800 as filter media in CWs may be compromised, due to certain limitations, for example: extremely high pH values in the post-adsorption solutions; high weight losses during calcination and adsorption processes; low mechanical strength; and intensive energy consumption. In contrast, the WHC demonstrated significant advantages of reasonably high P adsorption capacity, locally abundant availability, low cost, and marginal side effects. The fractionation of inorganic P of WHC and WHC-M800 revealed that Ca-bounded P was the most dominant binding form, followed by loosely bound P, Fe-P, occluded P, and Al-P. The present study demonstrates that recycling of WHC shells as a potential substrate in CWs provides a feasible method for upgrading P removal in CWs. Additionally, it helps to reduce waste WHC shells in a simple, cheap, and eco-friendly way, thus can double environmental benefits.
Nguyen, TH, Tran, HN, Vu, HA, Trinh, MV, Nguyen, TV, Loganathan, P, Vigneswaran, S, Nguyen, TM, Trinh, VT, Vu, DL & Nguyen, THH 2020, 'Laterite as a low-cost adsorbent in a sustainable decentralized filtration system to remove arsenic from groundwater in Vietnam', Science of The Total Environment, vol. 699, pp. 134267-134267.
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© 2019 Elsevier B.V. In the Red River Delta, Vietnam, arsenic (As) contamination of groundwater is a serious problem where more than seventeen million people are affected. Millions of people in this area are unable to access clean water from the existing centralized water treatment systems. They also cannot afford to buy expensive household water filters. Similar dangerous situations exist in many other countries and for this reason there is an urgent need to develop a cost-effective decentralized filtration system using new low-cost adsorbents for removing arsenic. In this study, seven locally available low-cost materials were tested for arsenic removal by conducting batch adsorption experiments. Of these materials, a natural laterite (48.7% Fe2O3 and 18.2% Al2O3) from Thach That (NLTT) was deemed the most suitable adsorbent based on arsenic removal performance, local availability, stability/low risk and cost (US$ 0.10/kg). Results demonstrated that the adsorption process was less dependent on the solution pH from 2.0 to 10. The coexisting anions competed with As(III) and As(V) in the order, phosphate > silicate > bicarbonate > sulphate > chloride. The adsorption process reached a fast equilibrium at approximately 120–360 min, depending on the initial arsenic concentrations. The Langmuir maximum adsorption capacities of NLTT at 30 °C were 512 μg/g for As(III) and 580 μg/g for As(V), respectively. Thermodynamic study conducted at 10 °C, 30 °C, and 50 °C suggested that the adsorption process of As(III) and As(V) was spontaneous and endothermic in nature. A water filtration system packed with NLTT was tested in a childcare centre in the most disadvantaged community in Ha Nam province, Vietnam, to determine arsenic removal performance in an operation lasting six months. Findings showed that the system reduced total arsenic concentration in groundwater from 122 to 237 μg/L to below the Vietnam drinking water standard of 10 μg/L.
Nguyen, TKL, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Nguyen, TV & Nghiem, DL 2020, 'Contribution of the construction phase to environmental impacts of the wastewater treatment plant', Science of The Total Environment, vol. 743, pp. 140658-140658.
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This study aims to investigate the environmental issues regarding the construction phase of the wastewater treatment plant (WWTP) and explore the roles of different materials through their environmental impacts. Detailed inventories of the two WWTPs were conducted by involving materials and transportation for civil works undertaken. EPD 2018 and ReCiPe life cycle impact assessment methods were employed to measure all the impact categories. Five treatment processes - (1) pumping, (2) primary treatment, (3) secondary treatment, (4) sludge line, and (5) building landscape - were considered for the assessment. It was found that concrete and reinforcing steel played similarly vital roles in most of the EPD 2018 impacts. The significant score of reinforcing steel was found on human cancer toxicity, which contributed more than 90% of the impacts. The contribution of diesel on ozone formation was 5% higher than that of reinforcing steel. Glassfiber was responsible for 70% of the burdens on ozone depletion, showing much higher than the total share of concrete and reinforcing steel. Primary treatment units only contributed 9.5% of the construction impacts in the Girona WWTP but up to 43.8% in Mill Creek WWTP mainly because of the proportion of consumed materials. In short, the comprehensive data inventories were necessary when evaluating the total environmental impacts of the WWTP.
Nguyen, TKL, Ngo, HH, Guo, WS, Chang, SW, Nguyen, DD, Nghiem, LD & Nguyen, TV 2020, 'A critical review on life cycle assessment and plant-wide models towards emission control strategies for greenhouse gas from wastewater treatment plants', Journal of Environmental Management, vol. 264, pp. 110440-110440.
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© 2020 Elsevier Ltd For decades, there has been a strong interest in mitigating greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs). Numerous models were developed to measure the emissions and propose the quantification. Existing studies looked at the relationship between GHG emissions and operational cost (OCI), which is one of the most important indicators for decision-makers. Other parameters that can influence the control strategies include the effluent quality (EQI) and total environmental impacts. Plant-wide models are reliable methods to examine the OCI, EQI and GHG emissions while Life cycle assessment (LCA) works to assess the potential environmental impacts. A combined LCA and plant-wide model proved to be a valuable tool evaluating and comparing strategies for the best performance of WWTPs. For this study involving a WWTP, the benchmark model is used while LCA is the decision tool to find the most suitable treatment strategy. LCA adds extra criteria that complement the existing criteria provided by such models. Complementing the cost/performance criteria is proposed for plant-wide models, including environmental evaluation, based on LCA, which provides an overall better assessment of WWTPs. It can capture both the dynamic effects and potential environmental impacts. This study provides an overview of the integration between plant-wide models and LCA.
Nguyen, TT, Ngo, HH, Guo, W & Wang, XC 2020, 'A new model framework for sponge city implementation: Emerging challenges and future developments', Journal of Environmental Management, vol. 253, pp. 109689-109689.
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© 2019 Sponge City concept is emerging as a new kind of integrated urban water systems, which aims to address urban water problems. However, its implementation has encountered a variety of challenges. The lack of an integrated comprehensive model to assist Sponge City planning, implementation and life cycle assessment is one of the most challenging factors. This review briefly analyses the opportunity of existing urban water management models and discusses the limitation of recent studies in the application of current integrated models for Sponge City implementation. Furthermore, it proposes a new Sponge City model framework by integrating four main sub-models including MIKE-URBAN, LCA, W045-BEST, and MCA in which environmental, social, and economic aspects of Sponge City infrastructure options are simulated. The new structure of Sponge City model that includes the sub-model layer, input layer, module layer, output layer, and programing language layer is also illustrated. Therefore, the proposed model could be applied to optimize different Sponge City practices by not only assessing the drainage capacity of stormwater infrastructure but also pays attention to multi-criteria analysis of urban water system (including the possibility of assessing Sponge City ecosystem services for urban areas and watershed areas) as well. Balancing between simplification and innovation of integrated models, increasing the efficiency of spatial data sharing systems, defining the acceptability of model complexity level and improving the corporation of multiple stakeholders emphasizing on possible future directions of a proper Sponge City design and construction model.
Nguyen, TT, Ngo, HH, Guo, W, Nguyen, HQ, Luu, C, Dang, KB, Liu, Y & Zhang, X 2020, 'New approach of water quantity vulnerability assessment using satellite images and GIS-based model: An application to a case study in Vietnam', Science of The Total Environment, vol. 737, pp. 139784-139784.
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Water deficiency due to climate change and the world's population growth increases the demand for the water industry to carry out vulnerability assessments. Although many studies have been done on climate change vulnerability assessment, a specific framework with sufficient indicators for water vulnerability assessment is still lacking. This highlights the urgent need to devise an effective model framework in order to provide water managers and authorities with the level of water exposure, sensitivity, adaptive capacity and water vulnerability to formulate their responses in implementing water management strategies. The present study proposes a new approach for water quantity vulnerability assessment based on remote sensing satellite data and GIS ModelBuilder. The developed approach has three layers: (1) data acquisition mainly from remote sensing datasets and statistical sources; (2) calculation layer based on the integration of GIS-based model and the Intergovernmental Panel on Climate Change's vulnerability assessment framework; and (3) output layer including the indices of exposure, sensitivity, adaptive capacity and water vulnerability and spatial distribution of remote sensing indicators and these indices in provincial and regional scale. In total 27 indicators were incorporated for the case study in Vietnam based on their availability and reliability. Results show that the most water vulnerable is the South Central Coast of the country, followed by the Northwest area. The novel approach is based on reliable and updated spatial-temporal datasets (soil water stress, aridity index, water use efficiency, rain use efficiency and leaf area index), and the incorporation of the GIS-based model. This framework can then be applied effectively for water vulnerability assessment of other regions and countries.
Nguyen, T-T-D, Nguyen, T-T, An Binh, Q, Bui, X-T, Ngo, HH, Vo, HNP, Andrew Lin, K-Y, Vo, T-D-H, Guo, W, Lin, C & Breider, F 2020, 'Co-culture of microalgae-activated sludge for wastewater treatment and biomass production: Exploring their role under different inoculation ratios', Bioresource Technology, vol. 314, pp. 123754-123754.
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In this study, mixed culture (microalgae:activated sludge) of a photobioreactor (PBR) were investigated at different inoculation ratios (1:0, 9:1, 3:1, 1:1, 0:1 wt/wt). This work was not only to determine the optimal ratio for pollutant remediation and biomass production but also to explore the role of microorganisms in the co-culture system. The results showed high total biomass concentrations were obtained from 1:0 and 3:1 ratio being values of 1.06, 1.12 g L-1, respectively. Microalgae played a dominant role in nitrogen removal via biological assimilation while activated sludge was responsible for improving COD removal. Compared with the single culture of microalgae, the symbiosis between microalgae and bacteria occurred at 3:1 and 1:1 ratio facilitated a higher COD removal by 37.5-45.7 %. In general, combined assessment based on treatment performance and biomass productivity facilitated to select an optimal ratio of 3:1 for the operation of the co-culture PBR.
Nguyen, TTQ, Loganathan, P, Nguyen, TV & Vigneswaran, S 2020, 'Removing arsenate from water using modified manganese oxide ore: Column adsorption and waste management', Journal of Environmental Chemical Engineering, vol. 8, no. 6, pp. 104491-104491.
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© 2020 Elsevier Ltd. There is a need to remove arsenic (As) in drinking water supplies by simple and cost-effective techniques. A column adsorption study was conducted to remove As(V) from water employing an iron (Fe) and zirconium (Zr) grafted Vietnamese manganese oxide ore (Fea-VMO and Zra-VMO). At a flow rate of 0.15 L/h, the bed volumes of water (As(V) concentration 0.1 mg/L) treated by Zra-VMO and Fea-VMO to produce water with As(V) concentration below the WHO guideline concentration (10 μg/L) were 6 and 8 times higher than for VMO, respectively. An increase in influent As concentration increased the adsorption capacity, but the increase of flow rate reduced the adsorption capacity. The maximum adsorption capacities derived from the Thomas model for VMO, Fea-VMO, and Zra-VMO at an influent concentration of 0.25 mg As(V)/L and flow rate of 0.15 L/h were 0.151, 1.145, and 0.925 mg/g, respectively. These values fell when influent As concentration decreased or the flow rate increased. Solidification/stabilisation method was applied to immobilise As(V) in the exhausted absorbent wastes by replacing 5, 10, 15, and 20 % of sand in a sand/cement concrete mixture by the adsorbent waste. This solidified material had satisfactory compressive strength, rapid chloride penetrability test, and volume of permeable voids, which indicated the material had good stability, making it suitable for use as a building material in construction work. The As(V) leaching from these materials, as measured by Method 1313 of the Leaching Environmental Assessment Framework of USEPA, proved to be very negligible.
Nguyen, TTQ, Loganathan, P, Nguyen, TV & Vigneswaran, S 2020, 'Removing arsenic from water with an original and modified natural manganese oxide ore: batch kinetic and equilibrium adsorption studies', Environmental Science and Pollution Research, vol. 27, no. 5, pp. 5490-5502.
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© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Arsenic contamination of drinking water is a serious water quality problem in many parts of the world. In this study, a low-cost manganese oxide ore from Vietnam (Vietnamese manganese oxide (VMO)) was firstly evaluated for its performance in arsenate (As(V)) removal from water. This material contains both Mn (25.6%) and Fe (16.1%) mainly in the form of cryptomelane and goethite minerals. At the initial As(V) concentration of 0.5 mg/L, the adsorption capacity of original VMO determined using the Langmuir model was 0.11 mg/g. The modified VMOs produced by coating VMO with iron oxide (Fea-VMO) and zirconium oxide (Zra-VMO) at 110 °C and 550 °C achieved the highest As(V) adsorption capacity when compared to three other methods of VMO modifications. Langmuir maximum adsorption capacities of Fea-VMO and Zra-VMO at pH 7.0 were 2.19 mg/g and 1.94 mg/g, respectively, nearly twenty times higher than that of the original VMO. Batch equilibrium adsorption data fitted well to the Langmuir, Freundlich, and Temkin models and batch kinetics adsorption data to pseudo-first order, pseudo-second order, and Elovich models. The increase of pH progressively from 3 to 10 reduced As(V) adsorption with a maximum reduction of 50–60% at pH 10 for both original and modified VMOs. The co-existing oxyanions considerably weakened the As(V) removal efficiency because they competed with As(V) anions. The competition order was PO43− > SiO32− > CO32− > SO42−. The characteristics of the original and modified VMOs evaluated using SEM, FTIR, XRD, XRF, surface area, and zeta potential explained the As(V) adsorption behaviour.
Nguyen, TTQ, Loganathan, P, Nguyen, TV, Vigneswaran, S & Ngo, HH 2020, 'Iron and zirconium modified luffa fibre as an effective bioadsorbent to remove arsenic from drinking water', Chemosphere, vol. 258, pp. 127370-127370.
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Porous luffa plant fibre (LF) was grafted with Fe and Zr, and the ability of the fabricated adsorbents to remove arsenate (As(V)) from water was investigated in batch and column adsorption experiments. The Langmuir adsorption capacity (mg g-1) at pH 7 of LF was found to be 0.035, which increased to 2.55 and 2.89 after being grafted with Fe (FLF-3) and Zr (ZLF-3), respectively. Grafting with Fe and Zr increased the zeta potential and zero point of charge (ZPC) of LF (from pH 3.9 to 7.4 for Fe grafting and to 7.6 for Zr grafting), due to chemical bonding of the metals, possibly with the hydroxyl and carboxylic groups in LF as indicated in FTIR peaks. Zeta potential and ZPC decreased after As adsorption owing to inner-sphere complexation mechanism of adsorption. The increase of pH from 3 to 10 progressively reduced the adsorbents' adsorption capacity. Co-existing anions weakened the As(V) removal efficiency in the order, PO43- > SiO32- > CO32- > SO42-. Adsorption kinetics data fitted well to the Weber and Morris model, which revealed initial fast and subsequent slow rates of intra-particle As diffusion into the bigger pores and smaller pores, respectively. Column adsorption data fitted well to the Thomas model with the predicted adsorption capacities in the same order as in the batch adsorption experiment (ZLF-3 > FLF-3 > LF).
Nguyen, XC, Tran, TCP, Hoang, VH, Nguyen, TP, Chang, SW, Nguyen, DD, Guo, W, Kumar, A, La, DD & Bach, Q-V 2020, 'Combined biochar vertical flow and free-water surface constructed wetland system for dormitory sewage treatment and reuse', Science of The Total Environment, vol. 713, pp. 136404-136404.
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A two-stage treatment system that included vertical flow (VF) and free-water surface (FWS) constructed wetlands was investigated for the dual purposes of sewage treatment and reuse. The VF included four layers (biochar, sand, gravel, and sandy soil), and the FWS was installed after the VF and used as a polishing tank. Two types of local plants, namely Colocasia esculenta and Canna indica, were planted in the VF and FWS, respectively. The system operated for approximately six months, and the experimental period was categorized into four stages that corresponded to changes in the hydraulic loading rate (HLR) (0.02-0.12 m/d). The removal efficiencies for total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD5), ammonia (NH4-N), and total coliform (Tcol) were 71 ± 11%, 73 ± 13%, 79 ± 11%, 91 ± 3%, and 70 ± 20%, respectively. At HLRs of 0.04-0.06 m/d, the COD and BOD5 levels satisfied Vietnam's irrigation standards, with removable rates of 64% and 88%, respectively, and the TSS and Tcol levels satisfied Vietnam's standards for potable water. Furthermore, the NO3-N levels satisfied the reuse limits, whereas the NH4-N levels exceeded the reuse standards. At high HLRs (e.g., 0.12 m/d), all the effluent parameters, except Tcol and NO3-N, exceeded the standards.
Ni, B-J, Yan, X, Dai, X, Liu, Z, Wei, W, Wu, S-L, Xu, Q & Sun, J 2020, 'Ferrate effectively removes antibiotic resistance genes from wastewater through combined effect of microbial DNA damage and coagulation', Water Research, vol. 185, pp. 116273-116273.
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The widespread of antibiotic resistance genes (ARGs) in the environment can pose severe threats to public health. The wastewater treatment plant (WWTP) is regarded as an important hotspot of ARGs in the urban environment, but the removal of ARGs through conventional treatment techniques has been proven not sufficient. In this study, ferrate (Fe(VI)) was applied for the first time to remove intracellular ARGs from the secondary effluent of the WWTP. The results showed that Fe(VI) treatment could effectively remove 15 ARGs covering eight different types as well as intI1, the most common integron important to ARGs horizontal transfer. The removal efficiencies of tested genes could reach 1.10-4.37 log at the Fe(VI) dosage of 10 mg-Fe/L, which is significantly higher than those achieved through traditional disinfection methods. The DNA gel electrophoresis suggested that Fe(VI) could induce microbial DNA damage and consequently resulted in ARGs elimination. The presence of ARGs in settled residues indicated that coagulation initiated by Fe(VI) reduction products also contributed to ARGs removal from wastewater. In addition, the viability and relative abundances of potential ARGs hosts in the wastewater were decreased after Fe(VI) treatment. This study suggested a promising prospect for applying Fe(VI) to efficiently remove ARGs from wastewater, and consequently to control their proliferation and transfer in the environment.
Ni, B-J, Zeng, S, Wei, W, Dai, X & Sun, J 2020, 'Impact of roxithromycin on waste activated sludge anaerobic digestion: Methane production, carbon transformation and antibiotic resistance genes', Science of The Total Environment, vol. 703, pp. 134899-134899.
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The macrolide antibiotic roxithromycin is widely detected in varying aquatic environments, especially in the wastewater systems, as an emerging contaminant and leads to significant impacts on the microorganisms involved. In this study, the impact of a shock load of roxithromycin on waste activated sludge (WAS) anaerobic digestion was comprehensively investigated. The biochemical methane potential tests showed that the methane production from WAS anaerobic digestion was significantly inhibited by roxithromycin. With the dosage of roxithromycin increasing from 0 to 1000 μg/L, the maximum cumulative methane production decreased from 163.5 ± 2.6 mL/g VS to 150.9 ± 4.5 mL/g VS. In particular, roxithromycin inhibited the acidogenesis and methanogenesis in WAS anaerobic digestion, leading to the decreased methane production. The methanogenic archaea in the studied system mainly belonged to the genera of Methanoseata, Candidatus Methanofastidiosum and Methanolinea and their relative abundances also decreased with roxithromycin addition. The analysis of antibiotic resistance genes (ARGs) in the digested sludge indicated that the abundances of most ARGs detected in this study were increased with roxithromycin exposure, suggesting the potential of growing antibiotic resistance, which was probably caused by enhancing the effect of esterases, methylases and phosphorylases. This work reveals how roxithromycin affects the WAS anaerobic digestion and the change of ARGs in the anaerobic digestion with roxithromycin exposure, and provides useful information for practical operation.
Ni, B-J, Zhu, Z-R, Li, W-H, Yan, X, Wei, W, Xu, Q, Xia, Z, Dai, X & Sun, J 2020, 'Microplastics Mitigation in Sewage Sludge through Pyrolysis: The Role of Pyrolysis Temperature', Environmental Science & Technology Letters, vol. 7, no. 12, pp. 961-967.
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© 2020 American Chemical Society. All rights reserved. Sewage sludge is an important source of introducing microplastics into the environment, and thus, effective mitigation of microplastics in the sludge is in urgent need. Herein, the effect of pyrolysis on microplastics reduction in sewage sludge was investigated through a lab-scale study. The micro-Raman analysis showed that the microplastics concentrations in sludge residues decreased significantly from 550.8 to 960.9 particles/g to 1.4-2.3 particles/g with the pyrolysis temperature increasing to 500 °C, and no tiny (10-50 μm) microplastics remained. Polyethylene and polypropylene, the two most abundant microplastics in sewage sludge, were entirely degraded when the pyrolysis temperature reached 450 °C. However, during the pyrolysis process, new plastic polymers could be produced through the reaction between original microplastics with organics in sludge, and heavy metals in sludge can also be combined. Moreover, scanning electron microscopy analysis of spiked microplastics showed that incomplete pyrolysis at low temperatures could result in rough surface morphology of microplastics, making it more readily to adsorb contaminants. Overall, the results of this study provide the first insight into the effectiveness of microplastics control in sewage sludge through pyrolysis, but to avoid potential environmental risks induced by incomplete pyrolysis, a pyrolysis temperature of 450 °C should be reached at least.
Nothling, MD, Fu, Q, Reyhani, A, Allison‐Logan, S, Jung, K, Zhu, J, Kamigaito, M, Boyer, C & Qiao, GG 2020, 'Progress and Perspectives Beyond Traditional RAFT Polymerization', Advanced Science, vol. 7, no. 20, pp. 2001656-2001656.
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AbstractThe development of advanced materials based on well‐defined polymeric architectures is proving to be a highly prosperous research direction across both industry and academia. Controlled radical polymerization techniques are receiving unprecedented attention, with reversible‐deactivation chain growth procedures now routinely leveraged to prepare exquisitely precise polymer products. Reversible addition‐fragmentation chain transfer (RAFT) polymerization is a powerful protocol within this domain, where the unique chemistry of thiocarbonylthio (TCT) compounds can be harnessed to control radical chain growth of vinyl polymers. With the intense recent focus on RAFT, new strategies for initiation and external control have emerged that are paving the way for preparing well‐defined polymers for demanding applications. In this work, the cutting‐edge innovations in RAFT that are opening up this technique to a broader suite of materials researchers are explored. Emerging strategies for activating TCTs are surveyed, which are providing access into traditionally challenging environments for reversible‐deactivation radical polymerization. The latest advances and future perspectives in applying RAFT‐derived polymers are also shared, with the goal to convey the rich potential of RAFT for an ever‐expanding range of high‐performance applications.
Nuruzzaman, M, Ren, J, Liu, Y, Rahman, MM, Shon, HK & Naidu, R 2020, 'Hollow Porous Silica Nanosphere with Single Large Pore Opening for Pesticide Loading and Delivery', ACS Applied Nano Materials, vol. 3, no. 1, pp. 105-113.
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Ong, HC, Mofijur, M, Silitonga, AS, Gumilang, D, Kusumo, F & Mahlia, TMI 2020, 'Physicochemical Properties of Biodiesel Synthesised from Grape Seed, Philippine Tung, Kesambi, and Palm Oils', Energies, vol. 13, no. 6, pp. 1319-1319.
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The production of biodiesel using vegetable oil is an effective way to meet growing energy demands, which could potentially reduce the dependency on fossil fuels. The aim of this study was to evaluate grape seed (Vitis vinifera), Philippine tung (Reutealis trisperma), and kesambi (Schleichera oleosa) oils as potential feedstocks for biodiesel production to meet this demand. Firstly, biodiesels from these oils were produced and then their fatty acid methyl ester profiles and physicochemical properties were evaluated and compared with palm biodiesel. The results showed that the biodiesel produced from grape seed oil possessed the highest oxidation stability of 4.62 h. On the other hand, poor oxidation stability was observed for Philippine tung biodiesel at 2.47 h. The poor properties of Philippine tung biodiesel can be attributed to the presence of α-elaeostearic fatty acid. Furthermore, synthetic antioxidants (pyrogallol) and diesel were used to improve the oxidation stability. The 0.2 wt.% concentration of pyrogallol antioxidant could increase the oxidation stability of grape seed biodiesel to 6.24 h, while for kesambi and Philippine tung, biodiesels at higher concentrations of 0.3% and 0.4 wt.%, respectively, were needed to meet the minimum limit of 8 h. The blending of biodiesel with fossil diesel at different ratios can also increase the oxidation stability.
Organ, B, Huang, Y, Zhou, JL, Yam, Y-S, Mok, W-C & Chan, EFC 2020, 'Simulation of engine faults and their impact on emissions and vehicle performance for a liquefied petroleum gas taxi', Science of The Total Environment, vol. 716, pp. 137066-137066.
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© 2020 Elsevier B.V. The deterioration of emissions control systems in a spark ignition engine is predominantly a gradual process of wear and tear occurring as vehicles accumulate mileage. As new innovations in engine and emissions technology have been progressively introduced to meet lower emissions targets, the impact of gradual deterioration of hardware has become more challenging to identify and quantify in the repair industry. When a pioneering emissions control programme utilising remote sensing to detect high emitting gasoline and liquefied petroleum gas (LPG) vehicles was to be introduced in Hong Kong, it became apparent the repair industry needed specialised training to assist with identifying the types of failures which would lead to high vehicle emissions. To identify the impact of hardware deterioration and failures, a Toyota Crown Comfort LPG taxi was used to demonstrate simulated failures of engine hardware systems to measure their impact on emissions, fuel consumption and drivability using a chassis dynamometer. This novel study simulated a broad range of deterioration and failures covering the intake, fuel supply, ignition, and exhaust systems. The results of the study showed significant THC and CO increases of up to 317% (0.604 g/km) and 782% (5.351 g/km) respectively for a simulated oxygen sensor high voltage fault and a sticky mixture control valve. The largest increase in NOx emissions was for restricted main fuel supply in the LPG vapouriser, producing an increase of 282% (1.41 g/km). Fuel consumption varied with increases of up to 15.5%. Drivability was impacted with poor idle from a number of faults and especially by a worn throttlebody which produced rough acceleration characteristics as well. This study clearly highlights the importance of having properly maintained emissions and engine hardware systems to achieve optimal fuel economy and compliant emissions levels, which could be reproduced in other regions for prescribed emiss...
Pardeshi, V, Nimbalkar, S & Khabbaz, H 2020, 'Field Assessment of Gravel Loss on Unsealed Roads in Australia', Frontiers in Built Environment, vol. 6, pp. 1-11.
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The gravel loss is a major limitation for unsealed roads and it needs major maintenance annually. The continual process of gravel loss leads to the unsustainability of these roads. The unsealed road management faces several issues, viz., difficulty to forecast behavior, huge data collection needs, and a vulnerability in the service and maintenance practices. The quality of gravel material also plays a major role in the process of gravel loss. In view of the aforementioned, appropriate revisions to ARRB material specifications are proposed in this study. The gravel material as per modified ARRB specifications is used on the unsealed road network in the Scenic Rim Regional Council in the state of Queensland. Gravel loss monitoring stations were established over the entire region in order to assess the gravel loss and the implication of using a better quality of gravel material. This study discusses the gravel loss monitoring approaches, data analyses, and improved material specification for gravel. It is found that the modified gravel used on unsealed road performs better than conventionally used gravel.
Park, J, Lim, J, Park, Y, Han, DS, Shon, HK, Hoffmann, MR & Park, H 2020, 'In Situ-Generated Reactive Oxygen Species in Precharged Titania and Tungsten Trioxide Composite Catalyst Membrane Filters: Application to As(III) Oxidation in the Absence of Irradiation', Environmental Science & Technology, vol. 54, no. 15, pp. 9601-9608.
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This study demonstrates that in situ-generated reactive oxygen species (ROSs) in prephotocharged TiO2 and WO3 (TW) composite particle-embedded inorganic membrane filters oxidize arsenite (As(III)) into arsenate (As(V)) without any auxiliary chemical oxidants under ambient conditions in the dark. TW membrane filters have been charged with UV or simulated sunlight and subsequently transferred to a once-through flow-type system. The charged TW filters can transfer the stored electrons to dissolved O2, producing ROSs that mediate As(III) oxidation in the dark. Dramatic inhibition of As(V) production with O2 removal or addition of ROS quenchers indicates an ROS-mediated As(III) oxidation mechanism. Electron paramagnetic spectroscopic analysis has confirmed the formation of the HO2•/O2•- pair in the dark. The WO3 fraction in the TW filter significantly influences the performance of the As(III) oxidation, while As(V) production is enhanced with increasing charging time and solution pH. The As(III) oxidation is terminated when the singly charged TW filter is fully discharged; however, recharging of TW recovers the catalytic activity for As(III) oxidation. The proposed oxidation process using charged TW membrane filters is practical and environmentally benign for the continuous treatment of As(III)-contaminated water during periods of unavailability of sunlight.
Parvin, K, Hannan, MA, Al-Shetwi, AQ, Ker, PJ, Roslan, MF & Mahlia, TMI 2020, 'Fuzzy Based Particle Swarm Optimization for Modeling Home Appliances Towards Energy Saving and Cost Reduction Under Demand Response Consideration', IEEE Access, vol. 8, pp. 210784-210799.
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Pathak, N, Phuntsho, S, Tran, VH, Johir, MAH, Ghaffour, N, Leiknes, T, Fujioka, T & Shon, HK 2020, 'Simultaneous nitrification-denitrification using baffled osmotic membrane bioreactor-microfiltration hybrid system at different oxic-anoxic conditions for wastewater treatment', Journal of Environmental Management, vol. 253, pp. 109685-109685.
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The efficacy of a baffled osmotic membrane bioreactor-microfiltration (OMBR-MF) hybrid system equipped with thin film forward osmosis membrane for wastewater treatment was evaluated at laboratory scale. The novel OMBR-MF hybrid system involved baffles, that separate oxic and anoxic zones in the aerobic reactor for simultaneous nitrification and denitrification (SND), and a bioreactor comprised of thin film composite-forward osmosis (TFC-FO) and polyether sulfone-microfiltration (PES-MF) membranes. The evaluation was conducted under four different oxic-anoxic cycle patterns. Changes in flux, salinity build-up, and microbial activity (e.g., extracellular polymeric substances (EPS) were assessed. Over the course of a 34 d test, the OMBR-MF hybrid system achieved high removal of total organic carbon (TOC) (86-92%), total nitrogen (TN) (63-76%), and PO4-P (57-63%). The oxic-anoxic cycle time of 0.5-1.5 h was identified to be the best operating condition. Incorporation of MF membrane effectively alleviated salinity build-up in the reactor, allowing stable system operation.
Pathak, N, Tran, VH, Merenda, A, Johir, MAH, Phuntsho, S & Shon, H 2020, 'Removal of Organic Micro-Pollutants by Conventional Membrane Bioreactors and High-Retention Membrane Bioreactors', Applied Sciences, vol. 10, no. 8, pp. 2969-2969.
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The ubiquitous presence of organic micropollutants (OMPs) in the environment as a result of continuous discharge from wastewater treatment plants (WWTPs) into water matrices—even at trace concentrations (ng/L)—is of great concern, both in the public and environmental health domains. This fact essentially warrants developing and implementing energy-efficient, economical, sustainable and easy to handle technologies to meet stringent legislative requirements. Membrane-based processes—both stand-alone or integration of membrane processes—are an attractive option for the removal of OMPs because of their high reliability compared with conventional process, least chemical consumption and smaller footprint. This review summarizes recent research (mainly 2015–present) on the application of conventional aerobic and anaerobic membrane bioreactors used for the removal of organic micropollutants (OMP) from wastewater. Integration and hybridization of membrane processes with other physicochemical processes are becoming promising options for OMP removal. Recent studies on high retention membrane bioreactors (HRMBRs) such as osmotic membrane bioreactor (OMBRs) and membrane distillation bioreactors (MDBRs) are discussed. Future prospects of membrane bioreactors (MBRs) and HRMBRs for improving OMP removal from wastewater are also proposed.
Pattison, TG, Spanu, A, Friz, AM, Fu, Q, Miller, RD & Qiao, GG 2020, 'Growing Patterned, Cross-linked Nanoscale Polymer Films from Organic and Inorganic Surfaces Using Ring-Opening Metathesis Polymerization', ACS Applied Materials & Interfaces, vol. 12, no. 3, pp. 4041-4051.
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The ability to modify substrates with thin polymer films allows for the tailoring of surface properties, and through combination of patterning finds use in a large variety of applications such as electronics and lab-on-chip devices. Although many techniques can be used to afford polymer-modified surfaces such as surface-initiated polymerization or layer-by-layer methodologies, their stability in a wide range of environments as well as their ability to target specific chemistry are critical factors to enable their successful application. In this paper, we report a facile technique in creating nanoscale polymer thin films using solid-state continuous assembly of polymers via ring-opening metathesis polymerization (ssCAPROMP) directly from surfaces functionalized through silanization. Using a polymeric precursor that includes norbornene moieties, a highly dense cross-linked network of polymer can be grown in a bottom-up fashion to afford thin films from an olefin-terminated silanized planar surface. Such nanotechnology affords films retaining the desirable qualities of previously reported methods while, at the same time, being covalently bound to the substrate: they are virtually pinhole free and can be reinitiated multiple times. By combining this process with microcontact printing, patterned films can be created by either the patterned deposition of a catalyst or by controlling the surface silanization chemistry and placement of olefin-terminated and nonreactive silanes. Additionally, patterned ssCAPROMP films were grown from SU-8 by selectively functionalizing the surface through masking and lift-off processes after the silanization step, thereby spatially controlling the surface-initiation, and subsequent polymer film formation. These patterned films expand the capabilities of the CAPROMP process and offer advantages over other film formation techniques in processes where patterned substrates and modified but robust surface chemistries are utilized.
Peng, L, Nie, W-B, Ding, J, Ni, B-J, Liu, Y, Han, H-J & Xie, G-J 2020, 'Denitrifying Anaerobic Methane Oxidation and Anammox Process in a Membrane Aerated Membrane Bioreactor: Kinetic Evaluation and Optimization', Environmental Science & Technology, vol. 54, no. 11, pp. 6968-6977.
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Denitrifying anaerobic methane oxidation (DAMO) coupled to anaerobic ammonium oxidation (anammox) is a promising technology for complete nitrogen removal with economic and environmental benefit. In this work, a model framework integrating DAMO and anammox process was constructed based on suspended-growth systems. The proposed model was calibrated and validated using experimental data from a sequencing batch reactor and a membrane aerated membrane bioreactor (MAMBR). The model managed to describe removal rates of ammonium (NH4+), nitrite (NO2-), and total nitrogen, as well as biomass changes of DAMO archaea, DAMO bacteria, and anaerobic ammonium oxidizing bacteria (AnAOB) in both reactors. The estimated parameter values revealed that DAMO archaea possessed properties of faster growth and higher biomass yield in suspended-growth systems compared to those in attached-growth systems (e.g., biofilm). Model simulation demonstrated that solid retention time (SRT) was effective in washing out DAMO bacteria, but retaining DAMO archaea and AnAOB in the MAMBR. The optimal SRT and nitritation efficiency (the ratio of the NO2- to the sum of NH4+ and NO2- in the MAMBR influent) were simulated so that 99% of total nitrogen was removed to meet the discharge standard. MAMBR further suggested to be operated with SRT between 15 and 30 days so that the optimal nitritation efficiency could be minimized to 49% for cost savings.
Pham, TT, Ngo, HH, Tran, VS & Nguyen, MK 2020, 'Removal of As (V) from the aqueous solution by a modified granular ferric hydroxide adsorbent', Science of The Total Environment, vol. 706, pp. 135947-135947.
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A novel adsorbent was prepared in granular form from iron (III) hydroxide and other additives to remove arsenate (As (V)) from aqueous solution. Adsorption of As (V) onto the adsorbent in batch experiments was analyzed to understand the adsorption mechanism, affecting factors, and adsorption isotherms. The optimal working conditions for the developed adsorbent were at pH 3, 30 °C and 50 g/L. The adsorption of arsenate onto the adsorbent occurred rapidly in the first 10 min and reached equilibrium in 2 h. The Langmuir isotherm was found to be best fitted the adsorption. The pre- and post-adsorption adsorbents were characterized by SEM, BET, FTIR, XRD, and Zeta potential techniques. Experimental results clearly demonstrated the potential impact of elemental composition, crystallinity, surface morphology, and other physico-chemical properties of the adsorbent on the adsorption performance variety. The experimental results with the pilot scale treatment system revealed that the adsorbent can be applied successfully and lead to a very efficient drinking water treatment system, at a competitive cost compared to the water market in Hanoi, Vietnam.
Phong Vo, HN, Ngo, HH, Guo, W, Hong Nguyen, TM, Li, J, Liang, H, Deng, L, Chen, Z & Hang Nguyen, TA 2020, 'Poly‐and perfluoroalkyl substances in water and wastewater: A comprehensive review from sources to remediation', Journal of Water Process Engineering, vol. 36, pp. 101393-101393.
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© 2020 Elsevier Ltd Per- and polyfluoroalkyl substances (PFAS) are pollutants have attracted major concern due to their high persistence and bioaccumulation. They are causing increasingly serious epidemiological problems in many communities globally due to consuming PFAS-contaminated water sources. Necessarily, the behavior of PFAS in water and wastewater needs to be understood better. This study attempts to comprehensively review, analyze and discuss PFAS based on the following key aspects: (i) sources, (ii) occurrence in water and wastewater, (iii) transformation, fate and migration, and (iv) remediation technologies. Studies indicated that modern water and wastewater treatment plants cannot deal completely with PFAS and in some cases, the removal efficiency is minus -3500-fold. The main reasons are the high hydrophobicity of PFAS and presence of PFAS precursors. Precursors can account for 33–63% of total PFAS concentration in water and wastewater. Detection and identification of precursors are challenging due to the requirement of advanced analytical instrument and standard chemicals. Several technologies have been developed for PFAS remediation involving two main mechanisms: separation-concentration and destruction. The most widespread in-use technology is adsorption because it is reasonably affordable. Anion exchange resin and synthesized materials are the most effective sorbents having a sorption capacity of 100–2000 mg PFAS/g sorbent, effective within a few hours. The destruction technology such as plasma can also be a promising one for degrading PFAS to below health-based standard in 1 min. However, plasma is costly and not yet ready for full scale application.
Phuntsho, S, Kim, JE, Tran, VH, Tahara, S, Uehara, N, Maruko, N, Matsuno, H, Lim, S & Shon, HK 2020, 'Free-standing, thin-film, symmetric membranes: Next-generation membranes for engineered osmosis', Journal of Membrane Science, vol. 607, pp. 118145-118145.
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© 2020 Elsevier B.V. The support layer of an asymmetric thin-film composite membrane results in structural resistance (internal concentration polarization) that significantly undermines engineered osmosis. Increasing the porosity and reducing the thickness and tortuosity of the membrane support layer reduces structural resistance; however, internal concentration polarization still impacts membrane performance. A novel, ultrathin, free-standing and symmetric membrane has been synthesized using sulfonated polyether ketone and tested for forward osmosis applications. This membrane is composed of a protonic acid group containing an aromatic polyether resin with sulfonated structural units. Polyether ketone provides high mechanical strength essential for ultrathin free-standing membranes, while sulfonation enhances the membrane hydrophilicity. These sulfonated polyether ketone membranes show promising water flux performances with impressive mechanical strength under the hydraulic operating conditions used for a FO process.
Pourzolfaghar, H, Abnisa, F, Wan Daud, WMA, Aroua, MK & Mahlia, TMI 2020, 'Catalyst Characteristics and Performance of Silica-Supported Zinc for Hydrodeoxygenation of Phenol', Energies, vol. 13, no. 11, pp. 2802-2802.
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The present investigation aimed to study the physicochemical characteristics of supported catalysts comprising various percentages of zinc dispersed over SiO2. The physiochemical properties of these catalysts were surveyed by N2 physisorption (BET), thermogravimetry analysis (TGA), H2 temperature-programmed reduction, field-emission scanning electron microscopy (FESEM), inductively coupled plasma-optical emission spectrometry (ICP-OES), and NH3 temperature-programmed desorption (NH3-TPD). In addition, to examine the activity and performance of the catalysts for the hydrodeoxygenation (HDO) of the bio-oil oxygenated compounds, the experimental reaction runs, as well as stability and durability tests, were performed using 3% Zn/SiO2 as the catalyst. Characterization of silica-supported zinc catalysts revealed an even dispersion of the active site over the support in the various dopings of the zinc. The acidity of the calcinated catalysts elevated clearly up to 0.481 mmol/g. Moreover, characteristic outcomes indicate that elevating the doping of zinc metal led to interaction and substitution of proton sites on the SiO2 surface that finally resulted in an increase in the desorption temperature peak. The experiments were performed at temperature 500 °C, pressure 1 atm; weight hourly space velocity (WHSV) 0.32 (h−1); feed flow rate 0.5 (mL/min); and hydrogen flow rate 150 (mL/min). Based on the results, it was revealed that among all the prepared catalysts, that with 3% of zinc had the highest conversion efficiency up to 80%. However, the selectivity of the major products, analyzed by gas chromatography flame-ionization detection (GC-FID), was not influenced by the variation in the active site doping.
Pramanik, BK, Nghiem, LD & Hai, FI 2020, 'Extraction of strategically important elements from brines: Constraints and opportunities', Water Research, vol. 168, pp. 115149-115149.
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Punetha, P, Nimbalkar, S & Khabbaz, H 2020, 'Analytical Evaluation of Ballasted Track Substructure Response under Repeated Train Loads', International Journal of Geomechanics, vol. 20, no. 7, pp. 04020093-04020093.
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© 2020 American Society of Civil Engineers. The irrecoverable deformations in the substructure layers are detrimental to the track stability and demand frequent maintenance. With an escalation in axle load and traffic volume, the frequency of maintenance operations has remarkably increased. Consequently, there is an inevitable need to predict the long-term behavior of the track substructure layers. This article presents a methodology to evaluate the recoverable and irrecoverable responses of the substructure layers under the train-induced repetitive loads. The present method utilizes an integrated approach combining track loading, resiliency, and settlement models. The track substructure layers are simulated as lumped masses that are connected by springs and dashpots. The method is successfully validated against the field investigation data reported in the literature. A parametric study is conducted to investigate the influence of substructure layer properties on the track response. The results reveal that the response of each track layer is significantly influenced by the neighboring layer properties and the incorporation of multilayered track structure enables more accurate prediction of track behavior. The present analytical approach is simple, computationally efficient and may assist the practicing engineers in the safer design of the ballasted track.
Punetha, P, Nimbalkar, S & Khabbaz, H 2020, 'Evaluation of additional confinement for three-dimensional geoinclusions under general stress state', Canadian Geotechnical Journal, vol. 57, no. 3, pp. 453-461.
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Three-dimensional cellular geoinclusions (e.g., geocells, scrap tires) offer all-around confinement to the granular infill materials, thus improving their strength and stiffness. The accurate evaluation of extra confinement offered by these geoinclusions is essential for predicting their performance in the field. The existing models to evaluate the additional confinement are based on either a plane-strain or axisymmetric stress state. However, these geoinclusions are more likely to be subjected to the three-dimensional stresses in actual practice. This note proposes a semi-empirical model to evaluate the additional confinement provided by cellular geoinclusions under the three-dimensional stress state. The proposed model is successfully validated against the experimental data. A parametric study is conducted to investigate the influence of input parameters on additional confinement. Results reveal that the simplification of the three-dimensional stress state into axisymmetric or plane-strain condition has resulted in inaccurate and unreliable results. The extra confinement offered by the geoinclusion shows substantial variation along the intermediate and minor principal stress directions depending on the intermediate principal stress, infill soil, and geoinclusion properties. The magnitude of additional confinement increases with an increase in the geoinclusion modulus. The findings are crucial for accurate assessment of the in situ performance of three-dimensional cellular geoinclusions.
Putra, N, Sandi, AF, Ariantara, B, Abdullah, N & Indra Mahlia, TM 2020, 'Performance of beeswax phase change material (PCM) and heat pipe as passive battery cooling system for electric vehicles', Case Studies in Thermal Engineering, vol. 21, pp. 100655-100655.
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© 2020 The Authors. Increasing greenhouse gas (GHG) emissions in the atmosphere and the scarcity of fossil fuel sources have encouraged car manufacturers to develop more environmentally friendly electric vehicles (EVs). The technology advancements of EVs - those with battery systems in particular - have increased their travel distances. Therefore, increasing and maintaining the battery capacity is a key concern in the development of sustainable EVs. In this study, passive cooling systems were constructed with a heat pipe and phase change material (PCM), and their performances were investigated with battery simulators. The aim was to determine the effectiveness of the cooling system and to identify the optimal PCM (beeswax or Rubitherm RT 44 HC) for a temperature range of 25-55 °C. The use of a heat pipe could decrease the battery temperature by 26.62 °C under a 60 W heat load compared to the case without passive cooling system. Furthermore, the addition of RT 44 to a heat pipe resulted in a maximal temperature decrease of 33.42 °C. Thus, an RT 44 HC is more effective than beeswax because its melting temperature lies within the recommended range of the battery working temperature, and its latent heat allows the absorption of more heat compared to beeswax.
Qi, C, Chen, H, Shen, L, Li, X, Fu, Q, Zhang, Y, Sun, Y & Liu, Y 2020, 'Superhydrophobic Surface Based on Assembly of Nanoparticles for Application in Anti-Icing under Ultralow Temperature', ACS Applied Nano Materials, vol. 3, no. 2, pp. 2047-2057.
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© 2020 American Chemical Society. A new class of superhydrophobic surface based on assembly of nanoparticles was fabricated for improving mechanical durability and anti-icing performance under ultralow temperature. Furthermore, the anti-icing performance and mechanism of the yielded superhydrophobic surface were investigated by high speed video and thermal infrared imaging equipment. The frozen time of water droplets could be prolonged to 372.0 s when glass slides with superhydrophobic surface were exposed to an ultralow temperature of -40.0 °C. This outstanding anti-icing performance is attributed to the unique structure of the superhydrophobic surface based on assembly of nanoparticles, which possesses good free-energy barrier and low heat transfer rate. This study thus opens up an avenue for the design and fabrication of superhydrophobic surface with good durability and anti-icing performance under ultralow temperature.
Qi, C, Chen, H, Sun, Y, Fu, Q, shen, L, Li, X & Liu, Y 2020, 'Facile synthesis and anti-icing performance of superhydrophobic flower-like OTS-SiO2 with tunable size', Advanced Powder Technology, vol. 31, no. 11, pp. 4533-4540.
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© 2020 The Society of Powder Technology Japan The superhydrophobic flower-like OTS-SiO2 particles with tunable size were synthesized for application in anti-icing technology, in which the nanosilica fibers were grown on surface of SiO2 sphere. Furthermore, the anti-icing process of flower-like OTS-SiO2 particles was investigated by a high speed video and thermal infrared imaging equipment. It was found that the flower-like OTS-SiO2 particles with a diameter of 300.0 nm showed best anti-icing ability, in which the frozen time of water droplets could be prolonged to 564.0 s at −25.0℃. The good anti-icing ability was attributed to micro-nano hierarchical structure and surface modification of flower-like OTS-SiO2 particles. The work has an important guiding implication for the subsequent design and preparation of superhydrophobic particles for application in anti-icing technology.
Qi, C, Chen, H, Sun, Y, Shen, L, Li, X, Fu, Q & Liu, Y 2020, 'Facile preparation of robust superhydrophobic surface based on multi‐scales nanoparticle', Polymer Engineering & Science, vol. 60, no. 8, pp. 1785-1794.
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AbstractA new superhydrophobic surface based on multi‐scales nanoparticle was designed and prepared to enhance the robustness and reproducibility. The influence of multi‐scale nanoparticles on the structure and property of the superhydrophobic surface was further investigated. The superhydrophobic surface with optimized composition did not only show high contact angle of 160°‐166.3° but also exhibited good durability to the mechanical, chemical, and thermal environments. Furthermore, the superhydrophobic surface was evaluated for application in anticorrosion, anti‐icing, and self‐cleaning. This study provides a new method to prepare robust superhydrophobic surface based on polymer nanocomposite coating for various potential applications.
Rao, RN, Silitonga, AS, Shamsuddin, AH, Milano, J, Riayatsyah, TMI, Sebayang, AH, Nur, TB, Sabri, M, Yulita, MR & Sembiring, RW 2020, 'Effect of Ethanol and Gasoline Blending on the Performance of a Stationary Small Single Cylinder Engine', Arabian Journal for Science and Engineering, vol. 45, no. 7, pp. 5793-5802.
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Rasouli, H & Fatahi, B 2020, 'Geofoam blocks to protect buried pipelines subjected to strike-slip fault rupture', Geotextiles and Geomembranes, vol. 48, no. 3, pp. 257-274.
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© 2019 Elsevier Ltd This paper proposes using geofoam blocks to improve the safety of buried steel pipelines under permanent ground deformation due to strike-slip fault rupture. Since these geofoam blocks are deformable, they can compress during fault rupture and thus reduce the pressure imposed on the pipeline by the surrounding soil. This means that the pipe can sustain a higher level of tectonic deformations. For the pipeline system adopted in this study, the geofoam blocks consist of two 1 m thick blocks at each side and another on the top of the pipeline. The effectiveness of this configuration is then assessed in comparison to the conventional buried pipeline by three dimensional numerical simulations that consider the interaction between soil and structure and the impact of critical parameters such as the pipeline-fault trace crossing angle, geofoam blocks thickness and the internal pressure of the pipeline. The results indicated that the geofoam blocks reduced the axial tensile strain of non-pressurised pipeline from the unacceptable 4.16% to the safe level of 0.75% when the crossing angle was 135°. In addition, geofoam blocks successfully decreased the maximum ovalisation parameter and compressive strain of the non-pressurised pipeline from 0.237 and −25.8% to 0.065 and −0.47%, respectively when the crossing angle was 65°.
Rasouli, H, Fatahi, B & Nimbalkar, S 2020, 'Liquefaction and post-liquefaction assessment of lightly cemented sands', Canadian Geotechnical Journal, vol. 57, no. 2, pp. 173-188.
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Post-liquefaction response of lightly cemented sands during an earthquake may change and become similar to uncemented sands due to bonding breakage. In the current study, the effect of degree of cementation on liquefaction and post-liquefaction behaviour of lightly cemented sands was studied through a series of cyclic and monotonic triaxial tests. Portland cement with high early strength and Sydney sand were used to reconstitute the lightly cemented specimens with unconfined compression strength ranging from 25 to 220 kPa. A series of multi-stage soil element tests including stress-controlled cyclic loading events with different amplitudes and post-cyclic undrained monotonic shearing tests were carried out on both uncemented and cemented specimens. Furthermore, a series of undrained monotonic shearing tests without cyclic loading history on different types of specimens was conducted to investigate the effect of cyclic loading history on the post-cyclic response of the specimens. The results show that residual excess pore-water pressure is correlated to the cyclic degradation of lightly cemented sands during cyclic loading. In addition, optical microstructure images of the cemented specimens after liquefaction showed that a major proportion of cementation bonds remained unbroken, which resulted in a superior post-liquefaction response with respect to initial stiffness and shear modulus in comparison to the uncemented sand.
Ratiko, R, Wisnubroto, DS, Nasruddin, N & Mahlia, TMI 2020, 'Current and future strategies for spent nuclear fuel management in Indonesia', Energy Strategy Reviews, vol. 32, pp. 100575-100575.
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© 2020 The Author(s) Currently, Indonesia has only three nuclear research reactors. However, Indonesia is the world's fourth most populous country. Owing to the enormous size and rapid growth of the population and the limited availability of fossil fuel and renewable energy resources, the construction of new nuclear power plants (NPPs) has been considered. Because of this, the management policies for long-term spent nuclear fuel in Indonesia have become crucial. This paper reviews the current handling and future management strategies for spent nuclear fuel in Indonesia. With a maximum capacity of 1448 spent fuel elements, Indonesia's interim wet storage of spent fuel (ISSF) is designed to store spent nuclear fuel arising from 25 years of reactor operation at maximum power. However, with the existing low-power reactor operation, the ISSF could be utilized for more than 75 years. The potential problem for long-term storage in the ISSF is system, structure, and component (SSC) aging. Continuous planning, operation, monitoring, and maintenance of the SSC in the ISSF have been conducted to ensure safe long-term utilization of the facility. In accordance with the possibility of NPP construction in the future, three possible scenarios may be considered for future nuclear spent fuel management strategies in Indonesia: 1) wet storage - dry storage - disposal; 2) wet storage -repatriation or sending to other countries; and 3) wet storage - moving to wet- or dry storage of NPP candidate - disposal.
Ren, L-F, Ngo, HH, Bu, C, Ge, C, Ni, S-Q, Shao, J & He, Y 2020, 'Novel external extractive membrane bioreactor (EMBR) using electrospun polydimethylsiloxane/polymethyl methacrylate membrane for phenol-laden saline wastewater', Chemical Engineering Journal, vol. 383, pp. 123179-123179.
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© 2019 Elsevier B.V. Phenol-laden saline wastewaters can adversely affect water, groundwater, soil, organisms and ecosystems. Given that frequently-used biodegradation process is generally inhibited by salinity, this work aims to solve the problem through a novel configuration of external extractive membrane bioreactor (EMBR) for the objective of simultaneous phenol permeation, salt rejection and biodegradation. Contact angles of 160.9 ± 2.2° (water) and 0.0° (phenol) were observed on the electrospun polydimethylsiloxane/polymethyl methacrylate (PDMS/PMMA) membrane, suggesting this superhydrophobic/superorganophilic membrane was suitable for separating phenol from water-soluble salt. Phenol ranging from 14.1 ± 2.7 to 290.7 ± 10.4 mg/L (stages 1 to 8) was continuously permeated and completely biodegraded in external EMBR under a hydraulic retention time (HRT) of 24 h, which corresponded with detoxification performance improving from 6.3% to 70.5%. After phenol exposure of 8 stages, Proteobacteria and Saccharibacteria became the main phyla for microorganisms. Enumeration of functional genes (phe, amoA, narG, nirS) confirmed that phenol was mainly consumed by denitrifiers and other heterotrophs as the sole carbon and energy source via oxidation and ring cleavage. As bacterial responses, these genes’ proliferation was promoted under low phenol concentrations but inhibited under high phenol concentrations. Meanwhile, results of extracellular polymeric substances revealed that protein was the key substance in toxicity resistance, phenol adsorption and transfer.
Ren, Y, Hao Ngo, H, Guo, W, Wang, D, Peng, L, Ni, B-J, Wei, W & Liu, Y 2020, 'New perspectives on microbial communities and biological nitrogen removal processes in wastewater treatment systems', Bioresource Technology, vol. 297, pp. 122491-122491.
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Biological nitrogen removal (BNR) is a critical process in wastewater treatment. Recently, there have new microbial communities been discovered to be capable of performing BNR with novel metabolic pathways. This review presents the up-to-date status on these microorganisms, including ammonia oxidizing archaea (AOA), complete ammonia oxidation (COMAMMOX) bacteria, anaerobic ammonium oxidation coupled to iron reduction (FEAMMOX) bacteria, anaerobic ammonium oxidation (ANAMMOX) bacteria and denitrifying anaerobic methane oxidation (DAMO) microorganism. Their metabolic pathways and enzymatic reactions in nitrogen cycle are demonstrated. Generally, these novel microbial communities have advantages over canonical nitrifiers or denitrifiers, such as higher substrate affinities, better physicochemical tolerances and/or less greenhouse gas emission. Also, their recent development and/or implementation in BNR is discussed and outlook. Finally, the key implications of coupling these microbial communities for BNR are identified. Overall, this review illustrates novel microbial communities that could provide new possibilities for high-performance and energy-saving nitrogen removal from wastewater.
Rizwanul Fattah, IM, Ong, HC, Mahlia, TMI, Mofijur, M, Silitonga, AS, Rahman, SMA & Ahmad, A 2020, 'State of the Art of Catalysts for Biodiesel Production', Frontiers in Energy Research, vol. 8.
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© Copyright © 2020 Rizwanul Fattah, Ong, Mahlia, Mofijur, Silitonga, Rahman and Ahmad. Biodiesel is one of the potential alternative energy sources that can be derived from renewable and low-grade origin through different processes. One of the processes is alcoholysis or transesterification in the presence of a suitable catalyst. The catalyst can be either homogeneous or heterogeneous. This article reviews various catalysts used for biodiesel production to date, presents the state of the art of types of catalysts, and compares their suitability and associated challenges in the transesterification process. Biodiesel production using homogeneous and heterogeneous catalysis has been studied extensively, and novel heterogeneous catalysts are being continuously investigated. Homogeneous catalysts are generally efficient in converting biodiesel with low free fatty acid (FFA) and water containing single-origin feedstock. Heterogeneous catalysts, on the other hand, provide superior activity, range of selectivity, good FFA, and water adaptability. The quantity and strengths of active acid or basic sites control these properties. Some of the heterogeneous catalysts such as zirconia and zeolite-based catalysts can be used as both basic and acidic catalyst by suitable alteration. Heterogeneous catalysts from waste and biocatalysts play an essential role in attaining a sustainable alternative to traditional homogeneous catalysts for biodiesel production. Recently, high catalytic efficiency at mild operating conditions has drawn attention to nanocatalysts. This review evaluates state of the art and perspectives for catalytic biodiesel production and assesses the critical operational variables that influence biodiesel production along with the technological solutions for sustainable implementation of the process.
Roobavannan, M, Kandasamy, J, Pande, S, Vigneswaran, S & Sivapalan, M 2020, 'Sustainability of agricultural basin development under uncertain future climate and economic conditions: A socio-hydrological analysis', Ecological Economics, vol. 174, pp. 106665-106665.
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© 2020 Elsevier B.V. A socio-hydrological model is used to forecast future conditions in a river basin arising from changes in climate and the economy in order to learn about macroeconomic conditions that would yield pathways for sustainable development and how they may be affected by changes in climate and the economy. The study uses a system dynamics model with endogenous social values and preferences and exogenous climate and economic drivers. Basin scale sustainability is defined as a function of economic growth, provision of environmental services and equality within the basin. The analysis reveals that a diversified basin economy is important to achieve sustainable development. Under current climate conditions, a higher level of diversification in the basin's economy increases sustainability. Higher current capital growth rates, e.g., >2% of the current rate, would also lead to more sustainable development of a kind that is less affected by the availability of water and robust to vagaries of climate change. The results suggest that policy-makers and resource managers should focus on measures to diversify the economy when it is thriving, but also consider the capacity of society to adapt to unpredictable shocks to the system.
Roobavannan, S, Vigneswaran, S & Naidu, G 2020, 'Enhancing the performance of membrane distillation and ion-exchange manganese oxide for recovery of water and lithium from seawater', Chemical Engineering Journal, vol. 396, pp. 125386-125386.
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© 2020 Elsevier B.V. Recovering lithium (Li) from natural sources such as seawater is a sustainable alternative to meet its high demands. Li recovery from seawater must be enhanced to attain economic efficiency. In this work, the potential of enhancing Li recovery from seawater by acid treated manganese oxide ion sieve (HMO) is evaluated by increasing Li concentration in seawater using direct contact membrane distillation (DCMD) and reducing competitive ions. DCMD achieved enhanced water recovery upon pre-treatment with oxalic acid (88–91%) compared to caustic soda ash (65–68%) and without pre-treatment (47–51%). Caustic soda ash required Na addition in alkaline condition for Ca removal, while, oxalic acid removed Ca in acidic condition without any inorganic ion addition. The low ion concentration in acidic condition upon oxalic acid pre-treatment enabled DCMD to concentrate seawater to high levels, increasing Li concentration by 7 times. In Li solution, HMO achieved a maximum adsorptive capacity (Langmuir Qmax) of 17.8 mg/g in alkaline condition. Multiple cycles of desorption and regeneration of HMO showed only 7–11% decline of Li uptake and minimal Mn dissolution, which, established HMO's reuse capacity. Selective Li mechanism is attributed to H/Li exchange as well as high negative surface charge of HMO. In seawater, Li uptake by HMO reduced by 44–46% due to Mg. Seawater with minimal Mg was favourable for enhancing Li uptake by HMO. Seawater treatment in stages – divalent pretreament and concentrating seawater, followed by HMO, provided a favourable scenario for attaining high quality water, selective Li recovery, and other resources – Ca and Mg.
Ryu, S, Naidu, G, Moon, H & Vigneswaran, S 2020, 'Selective copper recovery by membrane distillation and adsorption system from synthetic acid mine drainage', Chemosphere, vol. 260, pp. 127528-127528.
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Acid mine drainage (AMD) which involves high sulfur and heavy metals concentrations and furthermore are acidic in character, has been a major environmental and economic issue due to the associated toxicity and treatment costs. A large quantity of AMD in nature has a variety of resources including water and heavy metals such as Cu, Al, Fe and Ni. In this study, the valuable resource of Cu was selectively recovered from model AMD solution through membrane distillation and adsorption systems. Direct contact membrane distillation (DCMD) system enabled to concentrate the Cu concentration in AMD by more than 2.5 times while recovering 80% of high-quality water for reuse purposes. For adsorption, mesoporous silica material was used after multi-modification with Mn and amine grafting to enhance the adsorption capacity as well as selectivity for Cu. Under acidic conditions, heavy metals cannot be adsorbed on amine grafted SBA-15. Therefore, the pH of synthetic AMD (pH = 2.2) had to be adjusted to the 5.0-5.2 range, in order to enable adsorption of Cu on modified SBA-15 (this is to prevent protonation of amine groups grafted on prepared SBA-15). Moreover, an increase in pH helped to precipitate more than 99% of Fe and Al (predominant metals in AMD). Cu adsorption on modified SBA-15 was 24.53 mg/g for KOH-treated AMD. However, Cu adsorption on modified SBA-15 decreased by 26% (18.11 mg/g) for NaOH-treated AMD. Cu adsorption with modified SBA-15 significantly improved to 55.75 mg/g when the Cu concentration was concentrated by DCMD.
Safira, L, Putra, N, Trisnadewi, T, Kusrini, E & Mahlia, TMI 2020, 'Thermal properties of sonicated graphene in coconut oil as a phase change material for energy storage in building applications1', International Journal of Low-Carbon Technologies, vol. 15, no. 4, pp. 629-636.
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Abstract This study aims to investigate the thermal properties of a phase change material (PCM) based on coconut oil for building energy storage applications. Coconut oil is classified as an organic PCM composed of fatty acids made from renewable feedstock. However, low thermal conductivity is one of the major drawbacks of organic PCMs that must be improved. Graphene could be an effective material to enhance the thermal performance of organic PCMs. In this study, coconut oil with a latent heat capacity of 114.6 J/g and a melting point of 17.38°C was used. PCMs were prepared by sonicating graphene into coconut oil, as a supporting material. The mass fractions of the prepared PCMs were 0, 0.1, 0.2, 0.3, 0.4 and 0.5. Thermal conductivity tests were performed using a KD2 thermal property analyser under different ambient temperatures of 5, 10, 15, 20 and 25°C simulated with a circulating thermostatic bath. The latent heat, melting point and freezing point were determined through differential scanning calorimetry, the thermal stability was determined using thermogravimetric analysis (TGA) and the morphology and chemical structure were examined using transmission electron microscopy and Fourier-transform infrared spectroscopy, respectively. The results of this study showed that graphene addition to coconut oil improved the thermal performance, with the highest improvement seen in a 0.3 wt% sample at 20°C. The latent heat decreased by 11% owing to molecular movements within the PCM. However, TGA revealed that the composite PCMs showed good thermal stability in ambient building temperature ranges.
Samadi-Boroujeni, H, Abbasi, S, Altaee, A & Fattahi-Nafchi, R 2020, 'Numerical and Physical Modeling of the Effect of Roughness Height on Cavitation Index in Chute Spillways', International Journal of Civil Engineering, vol. 18, no. 5, pp. 539-550.
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© 2019, Iran University of Science and Technology. This study presents the results of physical and numerical modeling of the effect of bed roughness height of chute spillways on the cavitation index. A 1:50-scale physical hydraulic model of the chute spillway of Surk Dam was constructed at the hydraulic laboratory of Shahrekord University, Iran. The experiments were conducted for different flow rates and the parameters of pressure, velocity, and flow depth in 26 positions along the chute. Finally, the ANSYS-FLUENT model was calibrated in the chute spillway using the experimental data by assumptions of two-phase volume of fluid and k–ε (RNG) turbulence models. The cavitation index in different sections of the chute spillway was calculated for different values of bed roughness including the roughness heights of 1, 2, and 2.5 mm. Results showed that the minimum values of the cavitation index were 0.2906, 0.2733, and 0.2471 for the roughness heights of 1, 2, and 2.5 mm, respectively. The statistical significance analysis showed that reducing the roughness height from 2.5 to 1 mm would not change significantly the value of the cavitation index at 95% confidence interval.
Samaei, SM, Gato-Trinidad, S & Altaee, A 2020, 'Performance evaluation of reverse osmosis process in the post-treatment of mining wastewaters: Case study of Costerfield mining operations, Victoria, Australia', Journal of Water Process Engineering, vol. 34, pp. 101116-101116.
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© 2019 Elsevier Ltd Reverse Osmosis (RO) membrane has been used for treatment and purification of industrial wastewaters including those from the mining industry before being discharged to receiving body or reuse for applications that are fit for purpose. This study evaluates the performance of Reverse Osmosis (RO) plant as a post-treatment process in mining operations in Victoria, Australia. The data analysis shows that the RO unit significantly improves the quality of the final permeate before discharged to surface waters. Considering average rejection efficiency for the entire evaluated period, turbidity, total dissolved solids (TDS), Antimony, Arsenic, Nickel, Zinc and Iron concentrations are reduced by 85 %, 96 %, 95 %, 66 %, 82 %, 48 % and 10 %, respectively in the RO permeate compared to the feed water. Although the quality of the RO permeate was in a desirable condition in most days of the evaluated years, TDS concentrations on the October 11 and 20,2016 and November 14, 2017 were higher than the limits specified by Environmental Protection Authority (EPA) Victoria. Anomalies regarding antimony levels in RO permeate occurred in September and November 2016 as well as August 2017 due to inconsistency in the RO feed quality. This resulted in fouling of RO membranes and contributed to discharge non-compliance with EPA licence conditions on TDS and antimony. Discharge to waterways was suspended over the period when TDS and antimony contents were above the EPA guidelines. Changes in the pre-treatment reduced the turbidity of the feed water and improved the performance of the RO system to comply with the discharge guidelines.
Satya, A, Harimawan, A, Haryani, GS, Johir, MAH, Vigneswaran, S, Ngo, HH & Setiadi, T 2020, 'Batch Study of Cadmium Biosorption by Carbon Dioxide Enriched Aphanothece sp. Dried Biomass', Water, vol. 12, no. 1, pp. 264-264.
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The conventional method for cadmium removal in aqueous solutions (1–100 mg/L) is ineffective and inefficient. Therefore, a batch biosorption reactor using a local freshwater microalga (originating from an urban lake, namely, Situ Rawa Kalong-Depok) as dried biosorbent was tested. Biosorbent made from three kinds of cyanobacterium Aphanothece sp. cultivars (A0, A8, and A15) were used to eliminate cadmium (Cd2+) ions in aqueous solution (1–7 mg/L). The biosorbents were harvested from a photobioreactor system enriched with carbon dioxide gas of 0.04% (atmospheric), 8%, and 15% under continuous light illumination of about 5700–6000 lux for 14 d of cultivation. Produced dried biosorbents had Brunauer–Emmet–Teller (BET) surface area ranges of 0.571–1.846 m2/g. Biosorption of Cd2+ was pH and concentration dependent. Sorption was spontaneous (ΔG = −8.39 to −10.88 kJ/mol), exothermic (ΔH = −41.85 to −49.16 kJ/mol), and decreased randomness (ΔS = −0.102 to −0.126 kJ/mol. K) on the interface between solid and liquid phases when the process was completed. The kinetic sorption data fitted best to the pseudo-second-order model (k2 = 2.79 × 10−2, 3.96 × 10−2, and 4.54 × 10−2 g/mg.min). The dried biosorbents of A0, A8, and A15, after modeling with the Langmuir and Dubinin–Radushkevich isotherm models, indicated that cadmium binding occurred through chemisorption (qmax, D-R = 9.74 × 10−4, 4.79 × 10−3, and 9.12 × 10−3 mol/g and mean free energy of 8.45, 11.18, and 11.18 kJ/mol) on the monolayer and homogenous surface (qmax, Langmuir of 12.24, 36.90, and 60.24 mg/g). In addition, the results of SEM, EDX, and FTIR showed that there were at least nine functional groups that interacted with Cd2+ (led to bond formation) after biosorption through cation exchange mechanisms, and morphologically the surfaces changed after biosorption. Biosorbent A15 indicated the best resilient features over three cycles of sorption–desorption using 1 M HCl as the desorbing eluent. These...
Shahabuddin, M, Mofijur, M, Kalam, MA & Masjuki, HH 2020, 'Study on the Friction and Wear Characteristics of Bio-lubricant Synthesized from Second Generation Jatropha Methyl Ester', Tribology in Industry, vol. 42, no. 1, pp. 41-49.
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© 2020 Published by Faculty of Engineering. The demands for eco-friendly bio-lubricants are growing due to the environmental concern and the rapid depletion of petroleum oil. This paper outlines the tribological evaluation of jatropha methyl ester (JME) based bio-lubricant by analyzing its anti-wear (AW) and extreme pressure (EP) characteristics. The AW and EP tests were conducted using a four-ball tribotester with standard test methods of ASTM D 4172 and ASTM D 2783, respectively. After each test, the wear scar diameter, flash temperature parameter, viscosity and viscosity index (VI) were measured. The SEM analysis characterized the surface structure of the worn surface. The properties of formulated bio-lubricants were compared with the commercial lubricant SAE 15W-40. Experimental results showed that under boundary lubrication, the bio-lubricants showed excellent tribological properties up to the initial seizure load (ISL). Over the ISL, the friction and wear were increased slightly as compared to the commercial lubricant. The final seizure load (FSL) found for the bio-lubricant (BL 10), and commercial lubricant was 220 kg. The bio-lubricant with 10 % JME (BL 10) was found to be the most favorable, which met standard ISO requirements except for pour point.
Shanmugam, S, Ngo, H-H & Wu, Y-R 2020, 'Advanced CRISPR/Cas-based genome editing tools for microbial biofuels production: A review', Renewable Energy, vol. 149, pp. 1107-1119.
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© 2019 Elsevier Ltd With rapid progress in the fields of synthetic biology and metabolic engineering, there are possible applications to generate a wide range of advanced biofuels with maximized yield and productivity to achieve a more sustainable bioprocess with reduced carbon footprints. Among the diverse molecular biology tools, clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins (CRISPR-Cas) technology stands out with potential targeted genome editing, exhibiting a more precise and accurate gene knock-out and knock-in system better than its predecessors, for example zinc finger nucleases (ZFN) and transcription activator-like effector nucleases (TALEN). There are reports involved in the advanced microbial genome engineering tools for the biofuels production; however, there is lack of a comprehensive review about the CRISPR-Cas based-techniques in improved biofuel production along with the strategies to reduce the off-target effect that ensures the success and safety of this method. Therefore, in this review we attempt to systematically comment on the mechanism of CRISPR-Cas and its application to microbial biofuels production. This includes bioethanol, biobutanol as well as other hydrocarbons that sequentially follow various suggestions on enhancing the efficiency of targeting genes. The role of inducible on/off genetic circuits in response to environmental stimuli in the regulation of targeted genome editing (TGE) by minimizing metabolic burden and maximizing fermentation efficiency is also discussed. The relevant stringent regulatory demands to ensure minimal off-target cleavage with maximum efficiency coupled with complete biosafety of this technology are considered. It can be concluded that the recent development of CRISPR-Cas technology should open a new avenue in creating microbial biorefineries for potentially enhanced biofuel production.
Shen, Q, Lin, Y, Kawabata, Y, Jia, Y, Zhang, P, Akther, N, Guan, K, Yoshioka, T, Shon, H & Matsuyama, H 2020, 'Engineering Heterostructured Thin-Film Nanocomposite Membrane with Functionalized Graphene Oxide Quantum Dots (GOQD) for Highly Efficient Reverse Osmosis', ACS Applied Materials & Interfaces, vol. 12, no. 34, pp. 38662-38673.
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In this study, custom-tailored graphene oxide quantum dots (GOQD) were synthesized as functional nanofillers to be embedded into the polyamide (PA) membrane for reverse osmosis (RO) via interfacial polymerization (IP). The heterostructured interface-functionalization of amine/sulfonic decoration on GOQD (N/S-d-GOQD) takes place via the tuning of the molecular design. The embedded N/S-d-GOQD inside the PA matrix contributes to facilitating water molecules quick transport due to the more accessible capturing sites with higher internal polarity, achieving a nearly 3-fold increase in water permeance when compared to the pristine thin-film composite (TFC) membrane. Covalent bonding between the terminal amine groups and the acyl chloride of trimesoyl chloride (TMC) enables the formation of an amplified selective layer, while the sulfonic part assists in maintaining a robust membrane surface negative charge, thus remarkably improving the membrane selectivity toward NaCl. As a result, the newly developed TFN membrane performed remarkably high water permeance up to 5.89 L m-2 h-1 bar-1 without the compromising of its favorable salt (NaCl) rejection ratio of 97.1%, revealing a comparably high separation property when comparing to the state-of-the-art RO membranes, and surpassing the permeability-selectivity trade-off limits. Furthermore, we systematically investigated the GOQDs with different surface decorations but similar configurations (including 3 different nanofillers of pristine GOQD, amine decorated GOQD (N-d-GOQD), and N/S-d-GOQD) to unveil the underlying mechanisms of the swing effects of internal geometry and polarity of the embedded nanofillers on contributing to the uptake, and/or release of aqueous molecules within TFN membranes, providing a fundamental perspective to investigate the impact of embedded nanofillers on the formation of an IP layer and the overall transporting behavior of the RO process.
Shen, X, Zhang, J, Xie, H, Hu, Z, Liang, S, Ngo, HH, Guo, W, Chen, X, Fan, J & Zhao, C 2020, 'Intensive removal of PAHs in constructed wetland filled with copper biochar', Ecotoxicology and Environmental Safety, vol. 205, pp. 111028-111028.
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Silitonga, AS, Shamsuddin, AH, Mahlia, TMI, Milano, J, Kusumo, F, Siswantoro, J, Dharma, S, Sebayang, AH, Masjuki, HH & Ong, HC 2020, 'Biodiesel synthesis from Ceiba pentandra oil by microwave irradiation-assisted transesterification: ELM modeling and optimization', Renewable Energy, vol. 146, pp. 1278-1291.
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© 2019 Elsevier Ltd In this study, microwave irradiation-assisted transesterification was used to produce Ceiba pentandra biodiesel, which accelerates the rate of reaction and temperature within a shorter period. The improvement of biodiesel production requires a reliable model that accurately reflects the effects of input variables on output variables. In this study, an extreme learning machine integrated with cuckoo search algorithm was developed to predict and optimize the process parameters. This model will be useful for virtual experimentations in order to enhance biodiesel research and development. The optimum parameters of the microwave irradiation-assisted transesterification process conditions were obtained as follows: (1) methanol/oil ratio: 60%, (2) potassium hydroxide catalyst concentration: 0.84%(w/w), (3) stirring speed: 800 rpm, and (4) reaction time: 388 s. The corresponding Ceiba pentandra biodiesel yield was 96.19%. Three independent experiments were conducted using the optimum process parameters and the average biodiesel yield was found to be 95.42%. In conclusion, microwave irradiation-assisted transesterification is an effective method for biodiesel production because it is more energy-efficient, which will reduce the overall cost of biodiesel production.
Singh, R, Altaee, A & Gautam, S 2020, 'Nanomaterials in the advancement of hydrogen energy storage', Heliyon, vol. 6, no. 7, pp. e04487-e04487.
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The hydrogen economy is the key solution to secure a long-term energy future. Hydrogen production, storage, transportation, and its usage completes the unit of an economic system. These areas have been the topics of discussion for the past few decades. However, its storage methods have conflicted for on-board hydrogen applications. In this review, the promising systems based on solid-state hydrogen storage are discussed. It works generally on the principles of chemisorption and physisorption. The usage of hydrogen packing material in the system enhances volumetric and gravimetric densities of the system and helps in improving ambient conditions and system kinetics. Numerous aspects like pore size, surface area ligand functionalization and pore volume of the materials are intensively discussed. This review also examines the newly developed research based on MOF (Metal-Organic Frameworks). These hybrid clusters are employed for nano-confinement of hydrogen at elevated temperatures. A combination of the various methodologies may give another course to a wide scope in the area of energy storage materials later in the future.
Soja-Woźniak, M, Laiolo, L, Baird, ME, Matear, R, Clementson, L, Schroeder, T, Doblin, MA & Suthers, IM 2020, 'Effect of phytoplankton community size structure on remote-sensing reflectance and chlorophyll a products', Journal of Marine Systems, vol. 211, pp. 103400-103400.
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© 2020 Elsevier B.V. Remotely-sensed ocean colour is the main tool for estimating chlorophyll a (Chl-a) concentration and primary productivity on the global scale. In order to investigate the source of errors in remotely-sensed Chl-a concentration we obtained in situ bio-optical properties, in situ reflectances, satellite-derived reflectances and the Chl-a concentration satellite products of the Ocean and Land Colour Instrument (OLCI) Instrument on board Sentinel-3 A in waters off eastern Australia. The mesoscale eddies of these oligotrophic waters provide contrasting phytoplankton communities that allowed us to focus on the effect of phytoplankton size as a source of errors. In these waters, cold-core cyclonic eddies (CE) are dominated by large phytoplankton cells, while small cells dominate warm-core anticyclonic eddies (ACE). The chlorophyll-specific absorption and backscattering from contrasting sites show significant difference due to the differing package effect of phytoplankton size distributions. After normalising the absorption and backscattering spectra to Chl-a associated with just small phytoplankton, the spectra of optical properties become much more similar, showing that small-sized phytoplankton dominate IOPs even when large cells contain the greater fraction of Chl-a concentration of the phytoplankton community. Measured in situ reflectances agreed with reflectances calculated using a simple optical model based on measured IOPs. Furthermore, the in situ measured reflectances agreed well with the OLCI reflectance (mean normalised bias (MNB) of 7% for wavelengths <600 nm). However, a systematic underestimation of Chl-a concentrations by the OLCI algorithms was found in the region of cyclonic eddies characterised by increased Chl-a concentration and dominance of large-sized phytoplankton. A similar underprediction was found in Chl-a concentration calculated with the band-ratio OC4Me algorithm using in situ and IOP-calculated reflectance. Excluding Ch...
Song, Z, Zhang, X, Sun, F, Ngo, HH, Guo, W, Wen, H, Li, C & Zhang, Z 2020, 'Specific microbial diversity and functional gene (AOB amoA) analysis of a sponge-based aerobic nitrifying moving bed biofilm reactor exposed to typical pharmaceuticals', Science of The Total Environment, vol. 742, pp. 140660-140660.
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© 2018 Elsevier B.V. Four bench-scale sponge-based aerobic nitrifying moving bed biofilm reactors (MBBRs) were used to treat municipal wastewater containing typical pharmaceuticals (1 mg/L, 2 mg/L and 5 mg/L). This preliminary research aims to investigate the effects of sulfadiazine (SDZ), ibuprofen (IBU) and carbamazepine (CBZ) on nitrification performance and explore specific microbial diversity and functional gene (Ammonia-oxidizing bacteria (AOB), amoA) of MBBRs. After 90 days of operation, the MBBR without pharmaceuticals could remove up to 97.4 ± 1.5% of NH4+-N while the removals of NH4+-N by the MBBRs with SDZ, IBU and CBZ were all suppressed to varying degrees. Based on the Shannon and Chao 1 index, the specific microbial diversity and richness in biofilm samples increased at a range of 1 mg/L to 2 mg/L pharmaceuticals (SDZ, IBU or CBZ) and started decreasing after the pharmaceutical concentration was higher than 2 mg/L. The determination of functional gene (AOB amoA) showed that Proteobacteria was the most dominant bacteria within all biofilms with the relative abundance ranging from 24.81% to 55.32%. Furthermore, Nitrosomonas was the most numerous genus in AOB, followed by Campylobacter and Thauera, whose relative abundance shifted under the pressure of different pharmaceuticals.
Sornalingam, K, McDonagh, A, Canning, J, Cook, K, Johir, MAH, Zhou, JL & Ahmed, MB 2020, 'Photocatalysis of 17α-ethynylestradiol and estriol in water using engineered immersible optical fibres and light emitting diodes', Journal of Water Process Engineering, vol. 33, pp. 101075-101075.
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© 2019 Elsevier Ltd This research aims to promote photocatalysis of endocrine disrupting chemicals (EDCs) in water. Two reactor setups with (i) modified air-clad optical fibres and (ii) waterproof LED strips were utilised to transmit light to photocatalysts P25 TiO2 and gold-modified TiO2 (Au-TiO2). The performances to photodegrade 17α-ethynylestradiol (EE2) and estriol (E3) under Cool White and UVA high efficacy LEDs were examined. Au-TiO2 showed superior photocatalytic activity for EE2 removal over P25 TiO2. The pseudo first-order rate constants for EE2 photocatalysis under UVA were 0.55 h−1 and 0.89 h−1 for TiO2 and Au-TiO2, respectively. E3 was effectively degraded by Au-TiO2 in the immersible LED strip reactor (0.13 h−1).
Soudagar, MEM, Kalam, MA, Sajid, MU, Afzal, A, Banapurmath, NR, Akram, N, Mane, SD & Saleel C, A 2020, 'Thermal analyses of minichannels and use of mathematical and numerical models', Numerical Heat Transfer, Part A: Applications, vol. 77, no. 5, pp. 497-537.
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Soudagar, MEM, Nik-Ghazali, N-N, Kalam, MA, Badruddin, IA, Banapurmath, NR, Bin Ali, MA, Kamangar, S, Cho, HM & Akram, N 2020, 'An investigation on the influence of aluminium oxide nano-additive and honge oil methyl ester on engine performance, combustion and emission characteristics', Renewable Energy, vol. 146, pp. 2291-2307.
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The potential use of aluminium oxide nanoparticles as nanofuel additives was investigated on honge oil methyl ester and diesel fuel blend. The nanofuel blends were prepared by dispersing aluminium oxide in varying quantities in a HOME(B20) (20% biodiesel+80% diesel). Sodium dodecyl sulfate (SDS), an anionic surfactant, was used for a stable dispersion of aluminium oxide nanoparticles in the fuel blends. HOME(B20) fuel with concentration levels of 20, 40, and 60 ppm of aluminium oxide nanoparticles (HOME20, HOME2040 and HOME2060) with varying ratios of SDS surfactants were prepared using ultrasonication technique. The investigated properties of diesel, honge oil biodiesel and nanofuel blends were in agreement with the ASTM D6751-15 standards. The dispersion and homogeneity were established and characterized by using the Ultraviolet–Visible (UV–Vis) spectrometry. The UV–Vis spectrometry results illustrated an increase in absorbance level with a relative increase in the concentration of surfactant. The highest absolute value of UV-absorbency was observed for a mass fraction of 1:4 (Al2O3 NPs to SDS ratio). The investigation was performed at a constant speed of 1500 rpm, and BP of 0 kW, 1.04 kW, 3.12 kW, 4.16 kW and 5.20 kW. The fuel HOME2040 demonstrated an overall improvement in the engine parameters, the brake thermal efficiency (BTE) enhanced by 10.57%, while there was a decline in brake specific fuel consumption (BSFC) by 11.65% and the engine exhaust emission: HC, CO, and smoke reduced by 26.72%, 48.43%, and 22.84%, while the NOx increased by 11.27%. Similarly, the addition of aluminium oxide nanoparticles in HOME(B20) fuel blend resulted in decent reduction in the combustion duration (CD), ignition delay period (ID), improvement in the peak pressure, and a marginal increase in heat release rate (HRR) and cylinder pressure at maximum loading conditions. Based on the experimental results, it is concluded that the aluminium oxide nanoparticles in HOME(B...
Sukor, NR, Shamsuddin, AH, Mahlia, TMI & Mat Isa, MF 2020, 'Techno-Economic Analysis of CO2 Capture Technologies in Offshore Natural Gas Field: Implications to Carbon Capture and Storage in Malaysia', Processes, vol. 8, no. 3, pp. 350-350.
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Growing concern on global warming directly related to CO2 emissions is steering the implementation of carbon capture and storage (CCS). With Malaysia having an estimated 37 Tscfd (Trillion standard cubic feet) of natural gas remains undeveloped in CO2 containing natural gas fields, there is a need to assess the viability of CCS implementation. This study performs a techno-economic analysis for CCS at an offshore natural gas field in Malaysia. The framework includes a gas field model, revenue model, and cost model. A techno-economic spreadsheet consisting of Net Present Value (NPV), Payback Period (PBP), and Internal Rate of Return (IRR) is developed over the gas field’s production life of 15 years for four distinctive CO2 capture technologies, which are membrane, chemical absorption, physical absorption, and cryogenics. Results predict that physical absorption solvent (Selexol) as CO2 capture technology is most feasible with IRR of 15% and PBP of 7.94 years. The output from the techno-economic model and associated risks of the CCS project are quantified by employing sensitivity analysis (SA), which indicated that the project NPV is exceptionally sensitive to gas price. On this basis, the economic performance of the project is reliant on revenues from gas sales, which is dictated by gas market price uncertainties.
Sun, L, Zhou, JL & Cai, Q 2020, 'Impacts of soil properties on flow velocity under rainfall events: Evidence from soils across the Loess Plateau', CATENA, vol. 194, pp. 104704-104704.
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© 2020 Elsevier B.V. Flow velocity is one of the most significant hydraulic parameters directly connected to sediment transport-deposition processes. Four soils were collected from north to south of the Loess Plateau, namely Sandy Loess (SL), Loessial Soil (LS), Heilu Soil (HS) and Anthrosol Soil (AS), to examine the impacts of soil property on mean flow velocity in both interrill and rill flows under different simulated rainfall experiments. The mean velocity of interrill flow (MVIF) followed the order of LS > HS ≈ AS > SL at 90 mm h−1 rainfall intensity and LS > HS > AS > SL at 120 mm h−1 rainfall intensity. The mean velocity of rill flow (MVRF) decreased as LS ≈ HS > AS at 90 mm h−1 and LS ≈ HS > AS > SL at 120 mm h−1. The order of MVIF and MVRF on four soil slopes is determined by the relations of runoff discharge, Darcy-Weisbach friction factor in interrill area (fI) and rills (fR), which are closely related to soil properties. Soil properties also changed the effects of rainfall intensity on flow velocities in different erosion stages, resulting in the increasing trend of MVIF on SL, HS and AS slopes and the decreasing trend of MVIF on LS slope with the increase of rainfall intensity. Moreover, soil properties may change the variations of MVIF and MVRF with the increase of slope gradient, by altering the relations of sealing progress and slope effect. The slope effect determined the increasing trend of MVIF with the increase of slope gradients. However, the sealing progress may offset the slope effect and cause the decrease of MVIF on the critical slopes, and the critical slope decreased from the north (20° and 25°) to the south (15°). The equal roles of rill bed roughness and slope effect caused the unchanged of MVRF on LS and HS slopes, while rill bed roughness dominated the fluctuations of MVRF on SL and AS slopes.
Surawski, NC, Macdonald, LM, Baldock, JA, Sullivan, AL, Roxburgh, SH & Polglase, PJ 2020, 'Exploring how fire spread mode shapes the composition of pyrogenic carbon from burning forest litter fuels in a combustion wind tunnel', Science of The Total Environment, vol. 698, pp. 134306-134306.
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© 2019 In this study, solid state 13C nuclear magnetic resonance (NMR) spectroscopy was used to explore the carbon-containing functional groups present in pyrogenic carbon (PyC) produced during different fire spread modes to forest litter fuels from a dry sclerophyll eucalypt forest burnt in a combustion wind tunnel. A replicated experimental study was performed using three different fire spread modes: heading fires (i.e. fires which spread with the wind), flanking fires (i.e. fires which spread perpendicular to the wind) and backing fires (i.e. fires which spread against the wind). In addition to 13C NMR measurements of PyC, detailed fire behaviour measurements were recorded during experiments. Experiments showed that heading fires produced significantly more aryl carbon in ash samples than flanking fires. All other experimental comparisons for burnt fuel samples involving different fire spread modes were statistically insignificant. Principal component analysis (PCA) was used to explore the relationship between 13C NMR functional groups and fire behaviour observations. Results from PCA indicate that maximising the residence time of high temperature combustion and the combustion factor (i.e. the fraction of pre-fire biomass consumed by fire) could be a method for increasing the amount of aryl carbon in PyC. Maximising the amount of aryl carbon could be beneficial for the overall PyC balance from fire, since more recalcitrant carbon (e.g. carbon with a higher aryl carbon content) that is not emitted to the atmosphere has been shown to have longer residence times in environmental media such as soils or sediments.
Suryani, S, Sariani, S, Earnestly, F, Marganof, M, Rahmawati, R, Sevindrajuta, S, Mahlia, TMI & Fudholi, A 2020, 'A Comparative Study of Virgin Coconut Oil, Coconut Oil and Palm Oil in Terms of Their Active Ingredients', Processes, vol. 8, no. 4, pp. 402-402.
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This research aims to study the unique factors of virgin coconut oil (VCO) compared with coconut oil (i.e., coconut oil processed through heating the coconut milk and palm oil sold on the market). Its novelty is that it (VCO) contains lactic acid bacteria and bacteriocin. Lauric acid content was analyzed by the Chromatographic Gas method. Isolation of lactic acid bacteria (LAB) was conducted by the dilution method using MRSA + 0.5% CaCO3 media. Iodium number, peroxide, and %FFA were analyzed using a general method, and isolation bacteriocin by the deposition method using ammonium sulfate. In addition, macromolecular identification was conducted by 16S rRNA. VCO was distinguished by a higher content of lauric acid (C12:0) 41%–54.5% as compared with 0% coconut and 0, 1% palm oil, respectively. The VCO also contains LAB, namely Lactobacillus plantarum and Lactobacillus paracasei, and can inhibit the growth of pathogenic bacteria, such as Pseudomonas aeruginosa, Klebsiella, Staphylococcus aureus, S. epidermidis, Proteus, Escherichia coli, Listeria monocytogenes, Bacillus cereus, Salmonella typhosa and bacteriocin. Comparison with VCO is based on having a high content of lauric acid, 54%, and LAB content. The difference between VCO and coconut oil and palm oil is fatty acids. In VCO there are lauric acid and stearic acid, namely lauric acid VCO (A) 54.06%, VCO (B) 53.9% and VCO (C) 53.7%. The content of stearic acid VCO (A) is 12.03%, VCO (B) 12.01% and VCO (C) 11.9%. Coconut oil contains a little lauric acid, which is 2.81%, stearic acid 2.65% and palmitic acid 2.31%. Palm oil can be said to have very little lauric acid, namely in palm oil 1, 0.45%, and even in palm oil 2, 0%; in turn, palmitic acid palm oil 1 has 2.88% and palm oil 2 palmitic acid has 24.42%.
Sutherland, DL & Ralph, PJ 2020, '15 years of research on wastewater treatment high rate algal ponds in New Zealand: discoveries and future directions', New Zealand Journal of Botany, vol. 58, no. 4, pp. 334-357.
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© 2020, © 2020 The Royal Society of New Zealand. Over the last 15 years, New Zealand led research on wastewater treatment high rate algal ponds (HRAP) has focused on ways to optimise pond performance, particularly with respect to nutrient removal and resource recovery (microalgal biomass production). The primary motivation for most of this research has been the need to cost-effectively improve wastewater treatment, particularly in small towns and rural communities, where wastewater treatment would otherwise be unaffordable. The ability to recover resources (water and nutrients) helps enable a circular bio-economy, through the reuse of these recovered resources in future products. New Zealand HRAP research has focused on 10 broad categories, including improving pond performance (nutrient removal and biomass yield), environmental impacts of HRAPs, pond design and operation, microalgal and zooplankton community composition and control, algal-based products, enhancing phosphorus removal, biomass harvesting and emerging contaminants. Research has been carried out at a range of scales, including mesocosm, pilot-scale and full-scale. Simple modification to how HRAPs are operated, such as culture depth, operating ponds in series, biomass recycling and night-time CO2 addition, have been shown to improve pond performance, particularly nutrient removal, biomass productivity, species dominance maintenance or zooplankton graze control. However, despite our improved understandings over the last 15 years, there are still a number of priorities for increasing HRAP performance, including effective CO2 addition at full-scale, improving phosphorus removal and reducing potential environmental impacts of HRAPs. Uptake of HRAP technology by local government bodies and industries is low and the reasons for this are not fully clear. Cost-effective and sustainable harvesting of the microalgal/bacterial biomass, to ensure effluent discharge meets total nutrient and total suspended solids ...
Sutherland, DL, Burke, J & Ralph, PJ 2020, 'Flow-way water depth affects algal productivity and nutrient uptake in a filamentous algae nutrient scrubber', Journal of Applied Phycology, vol. 32, no. 6, pp. 4321-4332.
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© 2020, Springer Nature B.V. Filamentous algae treatment systems can provide cost-effective treatment of a range of wastewater types. In the current study, filamentous algae nutrient scrubbers (FANS), treating anaerobically digested food-waste centrate, were used to investigate the role of flow-way water depth (5, 10 and 15 mm) on productivity and nutrient removal. The study found that the proportion of light reaching the surface of the filamentous algae mat (Emat) increased with decreasing water depth, with 5-mm depth significantly higher than 10 mm (p < 0.05) and 15 mm (p < 0.01). On all sampling occasions, both the total solids and ash-free dry mass biomass productivities, as well as the chlorophyll a biomass, were all significantly higher (p < 0.01) on the FANS operated at 5 mm depth compared with 15 mm. Both the percentage carbon (C) and percentage phosphorus (P) were significantly higher in the biomass from 15 mm compared with 5 and 10 mm deep. Percentage nitrogen (N) content did not differ significantly between treatments but biological nitrogen removal rates (particulate N removed m−2 day−1) were significantly higher on the 5-mm-deep FANS compared with the 10 mm deep (p < 0.05) and the 15 mm deep (p < 0.01). The C:N ratio of algal biomass varied but not with depth whereas the C:P ratio significantly decreased (p < 0.01) with increasing water depth. These results indicate the important roles that light and water depth play on the performance of FANS.
Sutherland, DL, Burke, J, Leal, E & Ralph, PJ 2020, 'Effects of nutrient load on microalgal productivity and community composition grown in anaerobically digested food-waste centrate', Algal Research, vol. 51, pp. 102037-102037.
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© 2020 Elsevier B.V. Anaerobic digestion of food waste has many environmental benefits over traditional landfilling and is a promising technology to convert food waste to energy. However, the centrate, a liquid by-product of anaerobic digestion, is high in total ammonia, with concentrations ~20,000 g m−3, which requires treatment being discharged to the environment. Microalgae offer a promising and cost-effective treatment solution for this centrate but some dilution is required to prevent free-ammonia inhibition. In this study, we investigate the performance of microalgae, grown outdoors in high rate algal mesocosms, under three different total ammonia loads i) 20 g m−3 (20N), ii) 60 g m−3 (60 N) and iii) 100 g m−3 (100N). Both total suspended solids (TSS) and volatile suspended solids (VSS) increased with increasing nutrient load, with 100 N significantly higher (p < .01) than 60 N and 20 N biomass. The percentage nitrogen uptake was significantly higher in 20 N compared to 60 N (p < .05) and 100 N (p < .01). In contrast, the percentage biological uptake of phosphorus (P) did not differ significantly between treatments. Total microalgal biovolume increased with increasing nutrient load with nine species of chlorophytes (green algae) observed across all treatments throughout the experiment. Bray–Curtis percentage similarities between the microalgal community relative abundance, showed that the community in the 100 N treatment was at least 50% dissimilar to 20 N and 60 N, which were at least 75% similar to each other throughout the course of the experiment. These results indicate the capability of microalgae to bioremediate centrate from anaerobically digested food waste with high ammonia loading. Coupled centrate treatment and resource recovery could help support the circular bioeconomy.
Sutherland, DL, Howard-Williams, C, Ralph, P & Hawes, I 2020, 'Environmental drivers that influence microalgal species in meltwater pools on the McMurdo Ice Shelf, Antarctica', Polar Biology, vol. 43, no. 5, pp. 467-482.
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© 2020, Springer-Verlag GmbH Germany, part of Springer Nature. Rich in both microbial mat biomass and species diversity, the meltwater ponds of the McMurdo Ice Shelf (MIS) form important biodiversity and productivity elements in an otherwise barren landscape. These ponds are thought to be sensitive indicators of climate change-driven fluxes in pond water balance but our ability to predict such effects is confounded by our poor understanding of the inherent variability of these communities in response to the physico-chemical environment. Understanding how microbial communities are shaped across broad physico-chemical gradients may allow better predictions of the effects of climate change on the MIS wetlands. Our study found that distinct clustering of community types against environmental variables was apparent for both the diatom and cyanobacterial communities. For diatoms, conductivity was correlated with the separation of five significantly distinct communities. Significant differences in NH4–N concentrations were correlated to the three distinct cyanobacterial communities but many of the cyanobacteria morphotypes were recorded across a wide ecological range. More distinct community types suggested that diatoms were more sensitive to environmental change in these ponds than the cyanobacteria, despite the latter’s overall dominance. Distinct community clusters for diatoms, and to a lesser extent cyanobacteria, suggest that changes at a functional group level may be more important than at the level of individual species. Further understanding of diatom functional groups would provide us with the opportunity to hindcast past climates and water budgets within the Antarctic region. However, the disconnect between biomass and community composition currently prevents hindcasting past productivities in relation to environmental changes.
Sutherland, DL, Park, J, Heubeck, S, Ralph, PJ & Craggs, RJ 2020, 'Size matters – Microalgae production and nutrient removal in wastewater treatment high rate algal ponds of three different sizes', Algal Research, vol. 45, pp. 101734-101734.
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© 2019 Elsevier B.V. High rate algal ponds for coupled wastewater treatment and resource recovery have been the focus of much international research over the last 15 years. Microalgal biomass productivity reported in full-scale studies (1-ha or greater) have often been substantially lower than that reported from smaller scale ponds in similar climates, regardless of the season or the dominant microalgal species used. The disconnect between smaller-scale and full-scale productivity is unclear and uncertainty remains regarding the applicability of smaller scale studies to full-scale systems. In order to better understand the differences in reported productivity, the performance of three different size wastewater treatment high rate algal ponds (5 m2, 330 m2 and 1-ha) were assessed with respect to nutrient removal and microalgal productivity over three seasons. Both daily areal nutrient removal and biomass production were affected by the size of the pond. NH4-N removal via nitrification/denitrification decreased with increasing pond size, with the highest removal rate in the 5 m2 pond and the lowest in the 1-ha. Microalgal areal productivity was maximal in the 330 m2 pond, suggesting that a combination of mixing frequency and higher photosynthetic potential under low light conditions were the main drivers of enhanced productivity in this pond compared to the 5 m2 (mesocosm) and 1-ha (full-scale) ponds. The lowest daily nutrient removal and biomass production occurred in the 1-ha (full-scale) pond. Our results suggest that, based on the current design and operation of high rate algal ponds, the optimum size for maximum productivity is considerably smaller than the current full-scale systems. This has implications for commercial scale systems, with respect to capital and operational costs.
Sutherland, DL, Park, J, Ralph, PJ & Craggs, RJ 2020, 'Improved microalgal productivity and nutrient removal through operating wastewater high rate algal ponds in series', Algal Research, vol. 47, pp. 101850-101850.
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© 2020 Elsevier B.V. High rate algal ponds are recognised as a cost effective and efficient upgrade to conventional wastewater ponds for the treatment of a wide range of wastewaters. Their design allows microalgae to proliferate, which, in turn, results in high levels of nutrient removal, via algal assimilation. Furthermore, these ponds offer the opportunity to recover resources, in the form of algal biomass, for beneficial re-use, thus creating a circular bio-economy using wastewater. However, both increased microalgal biomass and nutrient removal is required to make coupled full-scale systems commercially viable. The performance of high rate algal ponds operated in series, on short hydraulic retention time of 4 days, versus in parallel, on a longer retention time of 8 days, was assessed with respect to nutrient removal and microalgal production. For microalgal productivity, the combined total volatile suspended solids (organic matter) and chlorophyll-a biomass were significantly higher (p < 0.01) under Series (191 ± 41 kg per day for volatile suspended solids) than Parallel (127 ± 18 kg per day) operation. The combined total dissolved inorganic nitrogen removed per day was significantly higher (p < 0.01) under Series (23 ± 4 kg of nitrogen per day) than Parallel (17 ± 4 kg) operation. The total amount of phosphorus removed per day was unaffected by mode of operation. Higher biomass production under short retention times came at the expense of nitrogen removal but treatment of the harvested effluent through a second pond in series, resulted in overall higher daily nitrogen removal and biomass production than ponds in parallel, for the same volume of wastewater treated. This study has demonstrated that with simple modifications to pond operation higher microalgal yields and improved effluent water quality without increased capital or operational costs.
Suwaileh, W, Pathak, N, Shon, H & Hilal, N 2020, 'Forward osmosis membranes and processes: A comprehensive review of research trends and future outlook', Desalination, vol. 485, pp. 114455-114455.
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Syahir, AZ, Harith, MH, Zulkifli, NWM, Masjuki, HH, Kalam, MA, Yusoff, MNAM, Zulfattah, ZM & Ibrahim, TM 2020, 'Compatibility of Ionic Liquid With Glycerol Monooleate and Molybdenum Dithiocarbamate as Additives in Bio-Based Lubricant', Journal of Tribology, vol. 142, no. 6.
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AbstractThis study reports the tribological characteristics of trimethylolpropane trioleate (TMPTO) additivated with antifriction and antiwear additives, which are ionic liquid (IL), glycerol monooleate (GMO), and molybdenum dithiocarbamate (MoDTC). In addition, to obtain the ideal composition that results in the minimal coefficient of friction (COF), optimization tool was employed using response surface methodology (RSM) technique with the Box–Behnken design. The IL used in this study was a phosphorus-type IL, namely trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl) phosphinate, [P14,6,6,6][TMPP]. The resulting COF and worn surface morphology were investigated using high-frequency reciprocating rig (HFRR) tribotester and scanning electron microscope with energy-dispersive X-ray spectroscopy (SEM-EDX), respectively. From the experimental results, a second-order polynomial mathematical model was constructed and able to statistically predict the resulting COF. The optimized values that resulted in the lowest average COF of 0.0458 were as follows: 0.93 wt% IL, 1.49 wt% GMO, and 0.52 wt% MoDTC. The addition of IL into neat base oil managed to reduce the COF, while the combination of IL, GMO, and MoDTC at optimum concentration further reduced the average COF and wear as observed through SEM micrographs when compared with those of additive-free TMPTO, suggesting that GMO and MoDTC were compatible to be used with IL.
Syahir, AZ, Zulkifli, NWM, Masjuki, HH, Kalam, MA, Harith, MH, Yusoff, MNAM, Zulfattah, ZM & Jamshaid, M 2020, 'Tribological Improvement Using Ionic Liquids as Additives in Synthetic and Bio-Based Lubricants for Steel–Steel Contacts', Tribology Transactions, vol. 63, no. 2, pp. 235-250.
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Tahmoorian, F & Khabbaz, H 2020, 'Performance comparison of a MSW settlement prediction model in Tehran landfill', Journal of Environmental Management, vol. 254, pp. 109809-109809.
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The municipal solid waste (MSW) landfills experience a large post-closure settlement over time. Waste settlement significantly impairs utilities, structures, and the other facilities constructed on top of a landfill. This study presents the settlement mechanisms and the methods of estimating MSW landfill settlements. Since the waste materials exhibit engineering properties which vary depending on many factors such as the location, time, climate, this study also presents the data related to the landfill characteristics, waste composition, waste moisture content, and other physical and chemical properties of waste. In addition, this paper discusses the findings of a settlement investigation conducted at a municipal solid waste landfill in Tehran. In this research, based on the collected field data and data obtained from the available literature, a technical management tool for MSW closed landfills has been developed using MATLAB, which aims to predict time dependent settlement under self-weight and surcharge loads in landfills considering various related parameters, leachate, gas generation, and moisture distribution, coefficients of compression, whilst it calculates different properties of wastes, and determines the landfill slope stability under various conditions. This user-friendly program captures the variation of the model parameters with time. The results of the verification process indicate that the results from the technical management tool have been in a very good agreement with the measured field settlement data, collected from Tehran landfill. Moreover, the results of sensitivity analysis of the model in regard to variation of input parameters indicate that there are two prominent characteristics, having significant impacts on the overall landfill settlement. These characteristics are the landfill height and the compressibility parameters. The outcomes of this study can improve the confidence for design and construction on MSW landfills. It ma...
Tijing, LD, Dizon, JRC, Ibrahim, I, Nisay, ARN, Shon, HK & Advincula, RC 2020, '3D printing for membrane separation, desalination and water treatment', Applied Materials Today, vol. 18, pp. 100486-100486.
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© 2019 Elsevier Ltd Additive manufacturing or commonly known as 3D printing is driving innovation in many industries and academic research including the water resource sector. The capability of 3D printing to fabricate complex objects in a fast and cost-effective manner makes it highly desirable over conventional manufacturing processes. Recent years have seen a rapid increase in research using 3D printing for membrane separation, desalination and water purification applications, potentially revolutionizing this field. This review focuses on recent advancements in 3D-printed materials and methods for water-related applications including developments in module spacers, novel filtration and desalination membranes, adsorbents, water remediation, solar steam generation materials, catalysis, etc. The emergence of new 3D printers with higher printing resolution, better efficiency, faster speed, and wider material applicability has garnered more interest and can potentially reshape research and development in this field. The promising potential, challenges and future prospects of 3D printing, additive manufacturing, and materials for water resource and treatment-related applications are all discussed in this review.
To, VHP, Nguyen, TV, Bustamante, H & Vigneswaran, S 2020, 'Effects of extracellular polymeric substance fractions on polyacrylamide demand and dewatering performance of digested sludges', Separation and Purification Technology, vol. 239, pp. 116557-116557.
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© 2020 Elsevier B.V. High polymer demand in sludge conditioning is an intractable aspect of the water industry. This study investigated the effects of extracellular polymeric substances (EPS) fractions on polyacrylamide demand for conditioning and dewatering performance. Specifically, it examined aerobically and anaerobically digested sludges from seven full-scale wastewater treatment plants (WWTPs). Our study successfully quantified the contributions of soluble EPS to polyacrylamide demand during conditioning and explained the role of tightly bound EPS (TB-EPS) in determining the digested sludges’ dewatering performance. Results show that the concentrations of soluble EPS in the sludges varied between 92 and 1148 mg/L. Experimental results also demonstrated that between 25% and 80% of polyacrylamides used for conditioning were wasted in “parasitic” reactions with soluble EPS. The residual cationic polyacrylamide left in solution, after the parasitic reactions, was substantial and varied between 35 and 254 mg/L. Despite this outcome, the zeta potential values of dewatered sludge cakes remained negative, i.e. between −24 and −35 mV. These indicated that the residual soluble cationic polyacrylamides would not have been absorbed on the negatively charged sludge particles. This explained the relatively poor performance of the dewatering stage in the treatment plants studied. Furthermore the results suggested the TB-EPS attached to the sludge particles would be responsible for the poor dewatering. We postulated that the TB-EPS would gelify and immobilize the water surrounding the sludge particles. Our study suggested that new and more effective polymers for conditioning are needed to both: (i) reduce polymer demand; and (ii) improve the dewatering performance.
Toriello, M, Afsari, M, Shon, H & Tijing, L 2020, 'Progress on the Fabrication and Application of Electrospun Nanofiber Composites', Membranes, vol. 10, no. 9, pp. 204-204.
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Nanofibers are one of the most attractive materials in various applications due to their unique properties and promising characteristics for the next generation of materials in the fields of energy, environment, and health. Among the many fabrication methods, electrospinning is one of the most efficient technologies which has brought about remarkable progress in the fabrication of nanofibers with high surface area, high aspect ratio, and porosity features. However, neat nanofibers generally have low mechanical strength, thermal instability, and limited functionalities. Therefore, composite and modified structures of electrospun nanofibers have been developed to improve the advantages of nanofibers and overcome their drawbacks. The combination of electrospinning technology and high-quality nanomaterials via materials science advances as well as new modification techniques have led to the fabrication of composite and modified nanofibers with desired properties for different applications. In this review, we present the recent progress on the fabrication and applications of electrospun nanofiber composites to sketch a progress line for advancements in various categories. Firstly, the different methods for fabrication of composite and modified nanofibers have been investigated. Then, the current innovations of composite nanofibers in environmental, healthcare, and energy fields have been described, and the improvements in each field are explained in detail. The continued growth of composite and modified nanofiber technology reveals its versatile properties that offer alternatives for many of current industrial and domestic issues and applications.
Tran, VH, Phuntsho, S, Han, DS, Dorji, U, Zhang, X & Shon, HK 2020, 'Submerged module of outer selective hollow fiber membrane for effective fouling mitigation in osmotic membrane bioreactor for desalination', Desalination, vol. 496, pp. 114707-114707.
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© 2020 Elsevier B.V. This paper investigated the membrane fouling mitigation efficacy and performance of a home-made submerged module containing outer selective hollow fiber thin film composite forward osmosis (OSHF TFC FO) membrane in osmosis membrane bioreactor (OMBR) system treating municipal wastewater for desalination. Initial tests, optimization of draw solution flowrate and pumping mode for the submerged module were carried out before it was applied into the OMBR system. Overall, the OMBR system exhibited an initial water flux of approximately 6.3 LMH using 35 g/L NaCl as draw solution, and high removal efficiencies of bulk organic matter and nutrients. Moreover, membrane fouling was effectively mitigated with slow rate of flux decline during 33-day operation of the OMBR system. These results indicated that the submerged membrane module of OSHF TFC FO membrane has stable and reliable performances making it suitable for OMBR supplication without the need of air scouring to prevent membrane fouling.
Trevathan-Tackett, SM, Jeffries, TC, Macreadie, PI, Manojlovic, B & Ralph, P 2020, 'Long-term decomposition captures key steps in microbial breakdown of seagrass litter', Science of The Total Environment, vol. 705, pp. 135806-135806.
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Seagrass biomass represents an important source of organic carbon that can contribute to long-term sediment carbon stocks in coastal ecosystems. There is little empirical data on the long-term microbial decomposition of seagrass detritus, despite this process being one of the key drivers of carbon-cycling in coastal ecosystems, that is, it influences the amount and quality of carbon available for sequestration. Here, our goal was to investigate how litter quality (leaf vs. rhizome/root) and the microbial communities involved in organic matter remineralisation shift over a 2-year field decomposition study north of Sydney, Australia using the temperate seagrass Zostera muelleri. The sites varied in bulk sediment characteristics and the sediment-associated microbial communities, but these variables overall had little influence on long-term seagrass decomposition rates or seagrass-associated microbiomes. The results showed a clear succession of bacterial and archaeal communities for both tissues types from r-strategists such as α- and γ-proteobacteria to K-strategies, including δ-proteobacteria, Bacteroidia and Spirochaetes. We used a new mathematical model to capture how decay rates varied over time and found that two decomposition events occurred for some seagrass leaf samples, possibly due to exudate input from living seagrass roots growing into the litter bag. The new model also indicated that conventional single exponential models overestimate long-term decay rates, and we detected for the first time the refractory, or stable, phase of decomposition for rhizome/root biomass. The stable phase began at approximately 20% mass remaining and after 600 days, and the persistence of rhizome/root biomass was attributed to the anoxic conditions and the preservation of refractory organic matter. While we predict that rhizome/root biomass will contribute more to the long-term sediment carbon stocks, the preservation of leaf carbon may be enhanced at locations were...
Trinh, VT, Nguyen, TMP, Van, HT, Hoang, LP, Nguyen, TV, Ha, LT, Vu, XH, Pham, TT, Nguyen, TN, Quang, NV & Nguyen, XC 2020, 'Phosphate Adsorption by Silver Nanoparticles-Loaded Activated Carbon derived from Tea Residue', Scientific Reports, vol. 10, no. 1, p. 3634.
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AbstractThis study presents the removal of phosphate from aqueous solution using a new silver nanoparticles-loaded tea activated carbon (AgNPs-TAC) material. In order to reduce costs, the tea activated carbon was produced from tea residue. Batch adsorption experiments were conducted to evaluate the effects of impregnation ratio of AgNPs and TAC, pH solution, contact time, initial phosphate concentration and dose of AgNPs-AC on removing phosphate from aqueous solution. Results show that the best conditions for phosphate adsorption occurred at the impregnation ratio AgNPs/TAC of 3% w/w, pH 3, and contact time lasting 150 min. The maximum adsorption capacity of phosphate on AgNPs-TAC determined by the Langmuir model was 13.62 mg/g at an initial phosphate concentration of 30 mg/L. The adsorption isotherm of phosphate on AgNPs-TAC fits well with both the Langmuir and Sips models. The adsorption kinetics data were also described well by the pseudo-first-order and pseudo-second-order models with high correlation coefficients of 0.978 and 0.966, respectively. The adsorption process was controlled by chemisorption through complexes and ligand exchange mechanisms. This study suggests that AgNPs-TAC is a promising, low cost adsorbent for phosphate removal from aqueous solution.
Truong, MV, Nguyen, LN, Li, K, Fu, Q, Johir, MAH, Fontana, A & Nghiem, LD 2020, 'Biomethane production from anaerobic co-digestion and steel-making slag: A new waste-to-resource pathway', Science of The Total Environment, vol. 738, pp. 139764-139764.
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Truong, NT, Thi, HPN, Ninh, HD, Phung, XT, Van Tran, C, Nguyen, TT, Pham, TD, Dang, TD, Chang, SW, Rene, ER, Ngo, HH, Nguyen, DD & La, DD 2020, 'Facile fabrication of graphene@Fe-Ti binary oxide nanocomposite from ilmenite ore: An effective photocatalyst for dye degradation under visible light irradiation', Journal of Water Process Engineering, vol. 37, pp. 101474-101474.
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© 2020 Elsevier Ltd Photocatalysis is an effective treatment technique for the removal of toxic pollutants present in water and wastewater. In this study, graphene@Fe-Ti binary oxide composites was prepared using a hydrothermal method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and Brunauer-Emmett-Teller surface area analysis. The prepared composite exhibited even distribution of the Fe-Ti binary oxide on the surface of graphene, with an average diameter of 16.4 nm and a surface area of 133.7 m2/g. The optical property was evaluated and the band gap was calculated to be 2.867 eV using solid-state UV–vis spectroscopy and the [F(R)hν]1/2 plot. Lab-scale experiments were performed to evaluate the performance of graphene@Fe-Ti binary oxides to remove methyl blue (i.e. a dye) from wastewater. It was observed that the graphene loading had a significant effect on the photocatalytic activity of the composite and a composite with 20 % graphene showed the highest photocatalytic activity, with 100 % removal of the dye, after 20 min of irradiation time and a degradation rate constant of 0.213 min−1. Besides, the possible photocatalytic dye degradation mechanism using graphene@Fe-Ti binary oxide composite has also been proposed.
Usman, M, Shi, Z, Ren, S, Ngo, HH, Luo, G & Zhang, S 2020, 'Hydrochar promoted anaerobic digestion of hydrothermal liquefaction wastewater: Focusing on the organic degradation and microbial community', Chemical Engineering Journal, vol. 399, pp. 125766-125766.
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Varjani, S, Joshi, R, Srivastava, VK, Ngo, HH & Guo, W 2020, 'Treatment of wastewater from petroleum industry: current practices and perspectives', Environmental Science and Pollution Research, vol. 27, no. 22, pp. 27172-27180.
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© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Petroleum industry is one of the fastest growing industries, and it significantly contributes to economic growth in developing countries like India. The wastewater from a petroleum industry consist a wide variety of pollutants like petroleum hydrocarbons, mercaptans, oil and grease, phenol, ammonia, sulfide, and other organic compounds. All these compounds are present as very complex form in discharged water of petroleum industry, which are harmful for environment directly or indirectly. Some of the techniques used to treat oily waste/wastewater are membrane technology, photocatalytic degradation, advanced oxidation process, electrochemical catalysis, etc. In this review paper, we aim to discuss past and present scenario of using various treatment technologies for treatment of petroleum industry waste/wastewater. The treatment of petroleum industry wastewater involves physical, chemical, and biological processes. This review also provides scientific literature on knowledge gaps and future research directions to evaluate the effect(s) of various treatment technologies available.
Verma, A, Hughes, DJ, Harwood, DT, Suggett, DJ, Ralph, PJ & Murray, SA 2020, 'Functional significance of phylogeographic structure in a toxic benthic marine microbial eukaryote over a latitudinal gradient along the East Australian Current', Ecology and Evolution, vol. 10, no. 13, pp. 6257-6273.
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AbstractGenetic diversity in marine microbial eukaryotic populations (protists) drives their ecological success by enabling diverse phenotypes to respond rapidly to changing environmental conditions. Despite enormous population sizes and lack of barriers to gene flow, genetic differentiation that is associated with geographic distance, currents, and environmental gradients has been reported from planktonic protists. However, for benthic protists, which have reduced dispersal opportunities, phylogeography and its phenotypic significance are little known. In recent years, the East Australian Current (EAC) has intensified its southward flow, associated with the tropicalization of temperate waters. Benthic harmful algal species have been increasingly found in south‐eastern Australia. Yet little is known about the potential of these species to adapt or extend their range in relation to changing conditions. Here, we examine genetic diversity and functional niche divergence in a toxic benthic dinoflagellate, Ostreopsis cf. siamensis, along a 1,500 km north–south gradient in southeastern Australia. Sixty‐eight strains were established from eight sampling sites. The study revealed long‐standing genetic diversity among strains established from the northern‐most sites, along with large phenotypic variation in observed physiological traits such as growth rates, cell volume, production of palytoxin‐like compounds, and photophysiological parameters. Strains from the southern populations were more uniform in both genetic and functional traits, and have possibly colonized their habitats more recently. Our study reports significant genetic and functional trait variability in a benthic harmful algal species, indicative of high adaptability, and a possible climate‐driven range extension. The observed high trait variation may facilitate development of harmful algal blooms under dynamic c...
Vilayphone, V, Outram, JG, Collins, F, Millar, GJ & Altaee, A 2020, 'Process design of coal seam gas associated water treatment plants to facilitate beneficial reuse', Journal of Environmental Chemical Engineering, vol. 8, no. 5, pp. 104255-104255.
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Vo, HNP, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Chen, Z, Wang, XC, Chen, R & Zhang, X 2020, 'Microalgae for saline wastewater treatment: a critical review', Critical Reviews in Environmental Science and Technology, vol. 50, no. 12, pp. 1224-1265.
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© 2019, © 2019 Taylor & Francis Group, LLC. Saline wastewater contains numerous pollutants such as nutrients, heavy metals, micropollutants, and organic pollutants. This kind of wastewater needs to be treated prior to discharging. Compared to other technologies for saline wastewater treatment, the microalgae process is considered to be ‘green’ or environmentally friendly as it generates no secondary pollutants and creates profit. To elucidate the issue, this review investigated the following: (1) the nature of saline wastewater; (2) adaptation of microalgae in saline wastewater; (3) pollutants’ remediation by microalgae in saline wastewater; (4) comparisons with other technologies; and (5) future perspectives. Most importantly, during microalgae process, the saline wastewater is transformed from a waste into a source for biofuel and pigment production. This trend implies to heal the environment, cut remediation expenses and raise revenue.
Vo, HNP, Ngo, HH, Guo, W, Liu, Y, Woong Chang, S, Nguyen, DD, Zhang, X, Liang, H & Xue, S 2020, 'Selective carbon sources and salinities enhance enzymes and extracellular polymeric substances extrusion of Chlorella sp. for potential co-metabolism', Bioresource Technology, vol. 303, pp. 122877-122877.
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This study investigated the extracellular polymeric substance (EPS) and enzyme extrusion of Chlorella sp. using seven carbon sources and two salinities for potential pollutant co-metabolism. Results indicated that the levels of biomass, EPS and enzymes of microalgae cultured with glucose and saccharose outcompeted other carbon sources. For pigment production, glycine received the highest chlorophyll and carotene, up to 10 mg/L. The EPS reached 30 mg/L, having doubled the amount of protein than carbohydrate. For superoxide dismutase and peroxidase enzymes, the highest concentrations were beyond 60 U/ml and 6 nmol/d.ml, respectively. This amount could be potentially used for degrading 40% ciprofloxacin of concentration 2000 µg/L. When increasing salinity from 0.1% to 3.5%, the concentrations of pigment, EPS and enzymes rose 3 to 30 times. These results highlighted that certain carbon sources and salinities could induce Chlorella sp. to produce EPS and enzymes for pollutant co-metabolism and also for revenue-raising potential.
Vo, HNP, Ngo, HH, Guo, W, Nguyen, KH, Chang, SW, Nguyen, DD, Liu, Y, Liu, Y, Ding, A & Bui, XT 2020, 'Micropollutants cometabolism of microalgae for wastewater remediation: Effect of carbon sources to cometabolism and degradation products', Water Research, vol. 183, pp. 115974-115974.
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This study investigated the impacts of selective sole carbon source-induced micropollutants (MPs) cometabolism of Chlorella sp. by: (i) extracellular polymeric substances (EPS), superoxide dismutase and peroxidase enzyme production; (ii) MPs removal efficiency and cometabolism rate; (iii) MPs' potential degradation products identification; and (iv) degradation pathways and validation using the Eawag database to differentiate the cometabolism of Chlorella sp. with other microbes. Adding the sole carbon sources in the presence of MPs increased EPS and enzyme concentrations from 2 to 100-fold in comparison with only sole carbon sources. This confirmed that MPs cometabolism had occurred. The removal efficiencies of tetracycline, sulfamethoxazole, and bisphenol A ranged from 16-99%, 32-92%, and 58-99%, respectively. By increasing EPS and enzyme activity, the MPs concentrations accumulated in microalgae cells also fell 400-fold. The cometabolism process resulted in several degradation products of MPs. This study drew an insightful understanding of cometabolism for MPs remediation in wastewater. Based on the results, proper carbon sources for microalgae can be selected for practical applications to remediate MPs in wastewater while simultaneously recovering biomass for several industries and gaining revenue.
Volpin, F, Badeti, U, Wang, C, Jiang, J, Vogel, J, Freguia, S, Fam, D, Cho, J, Phuntsho, S & Shon, HK 2020, 'Urine Treatment on the International Space Station: Current Practice and Novel Approaches', Membranes, vol. 10, no. 11, pp. 327-327.
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A reliable, robust, and resilient water recovery system is of paramount importance on board the International Space Station (ISS). Such a system must be able to treat all sources of water, thereby reducing resupply costs and allowing for longer-term space missions. As such, technologies able to dewater urine in microgravity have been investigated by different space agencies. However, despite over 50 years of research and advancements on water extraction from human urine, the Urine Processing Assembly (UPA) and the Water Processor Assembly (WPA) now operating on the ISS still achieve suboptimal water recovery rates and require periodic consumables resupply. Additionally, urine brine from the treatment is collected for disposal and not yet reused. These factors, combined with the need for a life support system capable of tolerating even dormant periods of up to one year, make the research in this field ever more critical. As such, in the last decade, extensive research was conducted on the adaptation of existing or emerging technologies for the ISS context. In virtue of having a strong chemical resistance, small footprint, tuneable selectivity and versatility, novel membrane-based processes have been in focus for treating human urine. Their hybridisation with thermal and biological processes as well as the combination with new nanomaterials have been particularly investigated. This article critically reviews the UPA and WPA processes currently in operation on the ISS, summarising the research directions and needs, highlighted by major space agencies, necessary for allowing life support for missions outside the Low Earth Orbit (LEO). Additionally, it reviews the technologies recently proposed to improve the performance of the system as well as new concepts to allow for the valorisation of the nutrients in urine or the brine after urine dewatering.
Volpin, F, Jiang, J, El Saliby, I, Preire, M, Lim, S, Hasan Johir, MA, Cho, J, Han, DS, Phuntsho, S & Shon, HK 2020, 'Sanitation and dewatering of human urine via membrane bioreactor and membrane distillation and its reuse for fertigation', Journal of Cleaner Production, vol. 270, pp. 122390-122390.
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© 2020 Elsevier Ltd Source separation and recovery of human urine have often been proposed as an effective way to achieve a more sustainable waste-to-resource cycle. Its high density of available macronutrients (N–P–K) in urine makes it an ideal raw material for the production of fertiliser. However, to improve the safety and public acceptance of urine-based fertilisers, odour and pathogens must be removed. In this work, low-temperature DCMD was investigated a mean to produce a non-odorous high-concentration liquid fertiliser. The effectiveness of urine-fertiliser in hydroponically growing leafy vegetables was benchmarked with a commercial solution. Also, prior to the DCMD, urine was biologically oxidised through an MBR which removed over 95% of the DOC and converted almost 50% of the NH3 into NO3−. The results showed that, despite the high salinity and high LMW organics in human urine, MD was still able to achieve a final product with TDS concentration up to 280 g.L−1. A sharp flux decline was measured after 80% water recovery, but alkaline cleaning effectively removed the thick fouling layer and fully recovered the initial flux. When used to grow lettuce and Pak Choi hydroponically, the produced urine fertiliser achieved promising performances as the biomass from the aerial part of the plants was often similar to the one obtained with commercial fertilisers. Overall, this article investigates the whole urine-to-biomass cycle, from collection to treatment to plant growth tests.
Volpin, F, Woo, YC, Kim, H, Freguia, S, Jeong, N, Choi, J-S, Cho, J, Phuntsho, S & Shon, HK 2020, 'Energy recovery through reverse electrodialysis: Harnessing the salinity gradient from the flushing of human urine', Water Research, vol. 186, pp. 116320-116320.
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Urine dilution is often performed to avoid clogging or scaling of pipes, which occurs due to urine's Ca2+ and Mg2+ precipitating at the alkaline conditions created by ureolysis. The large salinity gradient between urine and flushing water is, theoretically, a source of potential energy which is currently unexploited. As such, this work explored the use of a compact reverse electrodialysis (RED) system to convert the chemical potential energy of urine dilution into electric energy. Urine' composition and ureolysis state as well as solution pumping costs were all taken into account. Despite having almost double its electric conductivity, real hydrolysed urine obtained net energy recoveries ENet of 0.053-0.039 kWh/m3, which is similar to energy recovered from real fresh urine. The reduced performances of hydrolysed urine were linked to its higher organic fouling potential and possible volatilisation of NH3 due to its high pH. However, the higher-than-expected performance achieved by fresh urine is possibly due to the fast diffusion of uncharged urea to the freshwater side. Real urine was also tested as a novel electrolyte solution and its performance compared with a conventional K4Fe(CN)6/K3Fe(CN)6 couple. While K4Fe(CN)6/K3Fe(CN)6 outperformed urine in terms of power densities and energy recoveries, net chemical reactions seemed to have occurred in urine when used as an electrolyte solution, leading to TOC, ammonia and urea removal of up to 13%, 6% and 4.4%, respectively. Finally, due to the migration of K+, NH4+ and PO43-, the low concentration solution could be utilised for fertigation. Overall, this process has the potential of providing off-grid urine treatment or energy production at a household or building level.
Vu, HP, Nguyen, LN, Lesage, G & Nghiem, LD 2020, 'Synergistic effect of dual flocculation between inorganic salts and chitosan on harvesting microalgae Chlorella vulgaris', Environmental Technology & Innovation, vol. 17, pp. 100622-100622.
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© 2020 Elsevier B.V. The flocculation efficiency of microalgae Chlorella vulgaris for subsequent harvesting was investigated using single flocculants of inorganic salts, synthetic polymer, chitosan and dual flocculants of inorganic salts and chitosan. Synthetic polymer (FlopamTM) could achieve over 90% optical density removal (OD680removal) at a low flocculant dose (20 to 40 mg polymer per litre of algal suspension) through the bridging mechanism and charge neutralisation. Inorganic salts (i.e. ferric chloride and aluminium sulphate) and chitosan individually resulted in low flocculation efficiency (<90%) despite high dose (i.e. 160 to 200 mg per litre of algal suspension). The dual flocculation combining ferric chloride or aluminium sulphate with chitosan induced synergistic effects, resulting in >80% flocculation efficiency, significantly higher than the sum of each individual flocculation. The improvement in flocculation efficiency was 57 and 24% respectively for ferric chloride/chitosan and aluminium sulphate/chitosan. Charge neutralisation of microalgal cells by ferric chloride or aluminium sulphate combined with bridging by chitosan produced the synergy.
Vu, HP, Nguyen, LN, Vu, MT, Johir, MAH, McLaughlan, R & Nghiem, LD 2020, 'A comprehensive review on the framework to valorise lignocellulosic biomass as biorefinery feedstocks', Science of The Total Environment, vol. 743, pp. 140630-140630.
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An effective pretreatment is the first step to enhance the digestibility of lignocellulosic biomass - a source of renewable, eco-friendly and energy-dense materials - for biofuel and biochemical productions. This review aims to provide a comprehensive assessment on the advantages and disadvantages of lignocellulosic pretreatment techniques, which have been studied at the lab-, pilot- and full-scale levels. Biological pretreatment is environmentally friendly but time consuming (i.e. 15-40 days). Chemical pretreatment is effective in breaking down lignocellulose and increasing sugar yield (e.g. 4 to 10-fold improvement) but entails chemical cost and expensive reactors. Whereas the combination of physical and chemical (i.e. physicochemical) pretreatment is energy intensive (e.g. energy production can only compensate 80% of the input energy) despite offering good process efficiency (i.e. > 100% increase in product yield). Demonstrations of pretreatment techniques (e.g. acid, alkaline, and hydrothermal) in pilot-scale have reported 50-80% hemicellulose solubilisation and enhanced sugar yields. The feasibility of these pilot and full-scale plants has been supported by government subsidies to encourage biofuel consumption (e.g. tax credits and mandates). Due to the variability in their mechanisms and characteristics, no superior pretreatment has been identified. The main challenge lies in the capability to achieve a positive energy balance and great economic viability with minimal environmental impacts i.e. the energy or product output significantly surpasses the energy and monetary input. Enhancement of the current pretreatment techno-economic efficiency (e.g. higher product yield, chemical recycling, and by-products conversion to increase environmental sustainability) and the integration of pretreatment methods to effectively treat a range of biomass will be the steppingstone for commercial lignocellulosic biorefineries.
Vu, HP, Nguyen, LN, Zdarta, J, Nga, TTV & Nghiem, LD 2020, 'Blue-Green Algae in Surface Water: Problems and Opportunities', Current Pollution Reports, vol. 6, no. 2, pp. 105-122.
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Vu, MT, Vu, HP, Nguyen, LN, Semblante, GU, Johir, MAH & Nghiem, LD 2020, 'A hybrid anaerobic and microalgal membrane reactor for energy and microalgal biomass production from wastewater', Environmental Technology & Innovation, vol. 19, pp. 100834-100834.
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Wang, A, Wang, W, Chen, J, Mao, R, Pang, Y, Li, Y, Chen, W, Chen, D, Hao, D, Ni, B-J, Saunders, M & Jia, G 2020, 'Dominant Polar Surfaces of Colloidal II–VI Wurtzite Semiconductor Nanocrystals Enabled by Cation Exchange', The Journal of Physical Chemistry Letters, vol. 11, no. 13, pp. 4990-4997.
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Polar surfaces of ionic crystals are of growing technological importance, with implications for the efficiency of photocatalysts, gas sensors, and electronic devices. The creation of ionic nanocrystals with high percentages of polar surfaces is an option for improving their efficiency in the aforementioned applications but is hard to accomplish because they are less thermodynamically stable and prone to vanish during the growth process. Herein, we develop a strategy that is capable of producing polar surface-dominated II-VI semiconductor nanocrystals, including ZnS and CdS, from copper sulfide hexagonal nanoplates through cation exchange reactions. The obtained wurtzite ZnS hexagonal nanoplates have dominant {002} polar surfaces, occupying up to 97.8% of all surfaces. Density functional theory calculations reveal the polar surfaces can be stabilized by a charge transfer of 0.25 eV/formula from the anion-terminated surface to the cation-terminated surface, which also explains the presence of polar surfaces in the initial Cu1.75S hexagonal nanoplates with cation deficiency prior to cation exchange reactions. Experimental results showed that the HER activity could be boosted by the surface polarization of polar surface-dominated ZnS hexagonal nanoplates. We anticipate this strategy is general and could be used with other systems to prepare nanocrystals with dominant polar surfaces. Furthermore, the availability of colloidal semiconductor nanocrystals with dominant polar surfaces produced through this strategy opens a new avenue for improving their efficiency in catalysis, photocatalysis, gas sensing, and other applications.
Wang, B, Ni, B-J, Yuan, Z & Guo, J 2020, 'Unravelling kinetic and microbial responses of enriched nitrifying sludge under long-term exposure of cephalexin and sulfadiazine', Water Research, vol. 173, pp. 115592-115592.
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Wastewater treatment plants (WWTPs) have been identified as one of the reservoirs of antibiotics. Although nitrifying bacteria have been reported to be capable of degrading various antibiotics, there are very few studies investigating long-term effects of antibiotics on kinetic and microbial responses of nitrifying bacteria. In this study, cephalexin (CFX) and sulfadiazine (SDZ) were selected to assess chronic impacts on nitrifying sludge with stepwise increasing concentrations in two independent bioreactors. The results showed that CFX and SDZ at an initial concentration of 100 μg/L could be efficiently removed by enriched nitrifying sludge, as evidenced by removal efficiencies of more than 88% and 85%, respectively. Ammonia-oxidizing bacteria (AOB) made a major contribution to the biodegradation of CFX and SDZ via cometabolism, compared to limited contributions from heterotrophic bacteria and nitrite-oxidizing bacteria. Chronic exposure to CFX (≥30 μg/L) could stimulate ammonium oxidation activity in terms of a significant enhancement of ammonium oxidation rate (p < 0.01). In contrast, the ammonium oxidation activity was inhibited due to exposure to 30 μg/L SDZ (p < 0.01), then it recovered after long-term adaption under exposure to 50 and 100 μg/L SDZ. In addition, 16S rRNA gene amplicon sequencing revealed that the relative abundance of AOB decreased distinctly from 23.8% to 28.8% in the control phase (without CFX or SDZ) to 14.2% and 10.8% under exposure to 100 μg/L CFX and SDZ, respectively. However, the expression level of amoA gene was up-regulated to overcome this adverse impact and maintain a stable and efficient removal of both ammonium and antibiotics. The findings in this study shed a light on chronic effects of antibiotic exposure on kinetic and microbial responses of enriched nitrifying sludge in WWTPs.
Wang, G, Li, Y, Sheng, L, Xing, Y, Liu, G, Yao, G, Ngo, HH, Li, Q, Wang, XC, Li, Y-Y & Chen, R 2020, 'A review on facilitating bio-wastes degradation and energy recovery efficiencies in anaerobic digestion systems with biochar amendment', Bioresource Technology, vol. 314, pp. 123777-123777.
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In this review, progress in the potential mechanisms of biochar amendment for AD performance promotion was summarized. As adsorbents, biochar was beneficial for alleviating microbial toxicity, accelerating refractory substances degradation, and upgrading biogas quality. The buffering capacity of biochar balanced pH decreasing caused by volatile fatty acids accumulation. Moreover, biochar regulated microbial metabolism by boosting activities, mediating electron transfer between syntrophic partners, and enriching functional microbes. Recent studies also suggested biochar as potential useful additives for membrane fouling alleviation in anaerobic membrane bioreactors (AnMBR). By analyzing the reported performances based on different operation models or substrate types, debatable issues and associated research gaps of understanding the real role of biochar in AD were critically discussed. Accordingly, Future perspectives of developing biochar-amended AD technology for real-world applications were elucidated. Lastly, with biochar-amended AD as a core process, a novel integrated scheme was proposed towards high-efficient energy-resource recovery from various bio-wastes.
Wang, X, Guo, Z, Hu, Z, Ngo, H, Liang, S & Zhang, J 2020, 'Adsorption of phenanthrene from aqueous solutions by biochar derived from an ammoniation-hydrothermal method', Science of The Total Environment, vol. 733, pp. 139267-139267.
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Wang, Y, Liu, X, Liu, Y, Wang, D, Xu, Q, Li, X, Yang, Q, Wang, Q, Ni, B-J & Chen, H 2020, 'Enhancement of short-chain fatty acids production from microalgae by potassium ferrate addition: Feasibility, mechanisms and implications', Bioresource Technology, vol. 318, pp. 124266-124266.
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Anaerobic fermentation of microalgae was always hindered by its rigid cell wall structure. This paper reports a novel technique, i.e., adding potassium ferrate (K2FeO4) into microalgae fermentation systems to enhance short-chain fatty acids (SCFAs) production. The results showed that the maximum SCFAs production and acetic acid proportion were 732.6 mg COD/g VS and 54.6% at a dosage of 112.8 mg Fe(VI)/g VS, which were 168% and 208% of those in the control, respectively. Mechanism studies revealed that K2FeO4 effectively destroyed surface morphology and cell structure, and thus facilitated microalgae solubilization, providing a large number of biodegradable substrates for subsequent SCFA production. Although K2FeO4 inhibited all the microbial activities relevant to hydrolysis, acidification and methanogenesis processes to some degree, its inhibition to methanogens was much severer than that to other microbes. Illumina MiSeq sequencing analyses revealed that K2FeO4 addition increased the relative abundance (from 9.45% to 50.4%) of hydrolytic and SCFAs-forming bacteria.
Wang, Y, Wang, D, Yi, N, Li, Y, Ni, B-J, Wang, Q, Wang, H & Li, X 2020, 'Insights into the toxicity of troclocarban to anaerobic digestion: Sludge characteristics and methane production', Journal of Hazardous Materials, vol. 385, pp. 121615-121615.
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© 2019 Elsevier B.V. Triclocarban (TCC), as the most typical antibacterial agent, is widely discovered in many ecological environment, especially in sludge. However, so far, no studies have reported the effect of TCC exposure on the properties of excess sludge. Therefore, in this study, TCC's toxicities to waste activated sludge (WAS) were analyzed by investigating the variation of physicochemical properties of sludge. It was found that TCC exposure has no effect on sludge pH, while it facilitated organic substances release from sludge, e.g. dissolved organic matter (DOM), protein and polysaccharide, which caused an increase of sludge reduction and changed the structure of functional groups and surface morphology of sludge. Moreover, we explored the effect of TCC on anaerobic digestion of WAS and found methane production was seriously inhibited by TCC. The related mechanism tests had illustrated that TCC exposure did not affect the hydrolysis process, but promoted the acidification and acetogenesis, and importantly inhibited the methanogenesis process. Methanogenic community was further evaluated and observed that the presence of TCC could vary the microbial community of methanogens with the abundance of aceticlastic methanogens increasing and hydrogenotrophic methanogens decreasing. These findings reached in this study would widen the understanding scope for TCC's toxicity to WAS.
Wang, Y, Wei, W, Wu, S-L & Ni, B-J 2020, 'Zerovalent Iron Effectively Enhances Medium-Chain Fatty Acids Production from Waste Activated Sludge through Improving Sludge Biodegradability and Electron Transfer Efficiency', Environmental Science & Technology, vol. 54, no. 17, pp. 10904-10915.
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A novel zerovalent iron (ZVI) technique to simultaneously improve the production of medium-chain fatty acids (MCFAs) from waste activated sludge (WAS) and enhance WAS degradation during anaerobic WAS fermentation was proposed in this study. Experimental results showed that the production and selectivity of MCFAs were effectively promoted when ZVI was added at 1-20 g/L. The maximum MCFAs production of 15.4 g COD (Chemical Oxygen Demand)/L and MCFAs selectivity of 71.7% were both achieved at 20 g/L ZVI, being 5.3 and 4.8 times that without ZVI (2.9 g COD/L and 14.9%). Additionally, ZVI also promoted WAS degradation, which increased from 0.61 to 0.96 g COD/g VS when ZVI increased from 0 to 20 g/L. The microbial community analysis revealed that the ZVI increased the populations of key anaerobes related to hydrolysis, acidification, and chain elongation. Correspondingly, the solubilization, hydrolysis, and acidification processes of WAS were revealed to be improved by ZVI, thereby providing more substrates (short-chain fatty acids (SCFAs)) for producing MCFAs. The mechanism studies showed that ZVI declined the oxidation-reduction potential (ORP), creating a more favorable environment for the anaerobic biological processes. More importantly, ZVI with strong conductivity could act as an electron shuttle, contributing to increasing electron transfer efficiency from electron donor to acceptor. This strategy provides a new paradigm of transforming waste sludge into assets by a low-cost waste to bring significant economic benefits to sludge disposal and wastewater treatment.
Waqas, S, Bilad, MR, Man, Z, Wibisono, Y, Jaafar, J, Indra Mahlia, TM, Khan, AL & Aslam, M 2020, 'Recent progress in integrated fixed-film activated sludge process for wastewater treatment: A review', Journal of Environmental Management, vol. 268, pp. 110718-110718.
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Integrated fixed-film activated sludge (IFAS) process is considered as one of the leading-edge processes that provides a sustainable solution for wastewater treatment. IFAS was introduced as an advancement of the moving bed biofilm reactor by integrating the attached and the suspended growth systems. IFAS offers advantages over the conventional activated sludge process such as reduced footprint, enhanced nutrient removal, complete nitrification, longer solids retention time and better removal of anthropogenic composites. IFAS has been recognized as an attractive option as stated from the results of many pilot and full scales studies. Generally, IFAS achieves >90% removals for combined chemical oxygen demand and ammonia, improves sludge settling properties and enhances operational stability. Recently developed IFAS reactors incorporate frameworks for either methane production, energy generation through algae, or microbial fuel cells. This review details the recent development in IFAS with the focus on the pilot and full-scale applications. The microbial community analyses of IFAS biofilm and floc are underlined along with the special emphasis on organics and nitrogen removals, as well as the future research perspectives.
Wei, W, Guo, W, Ngo, HH, Mannina, G, Wang, D, Chen, X, Liu, Y, Peng, L & Ni, B-J 2020, 'Enhanced high-quality biomethane production from anaerobic digestion of primary sludge by corn stover biochar', Bioresource Technology, vol. 306, pp. 123159-123159.
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This study conducted batch and continuous tests to reveal the feasibility of corn stover biochar on improving anaerobic digestion of primary sludge (PS). Dosing biochar (1.82, 2.55 and 3.06 g/g Total Solids (TS)) in digester improved methane content increasing from 67.5% to 81.3-87.3% and enhanced methane production by 8.6-17.8%. Model analysis indicated that biochar accelerated PS hydrolysis and enhanced methane potential of PS. The mechanistic studies showed that biochar enhanced process stability provided by strong buffering capacity and alleviated NH3 inhibition. In continuous test over 116 days, the volatile solids (VS) destruction in the biochar-dosed digester increased by 14.9%, resulting in a 14% reduction in the volume of digestate for disposal. Biochar changed microbial community in an expected direction for anaerobic digestion. This work suggests that biochar technology would apply to co-digestion of WAS and PS to maximize the energy recovery and sludge reduction from the two sludge streams.
Wei, W, Hao, Q, Chen, Z, Bao, T & Ni, B-J 2020, 'Polystyrene nanoplastics reshape the anaerobic granular sludge for recovering methane from wastewater', Water Research, vol. 182, pp. 116041-116041.
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Wastewater has been identified as an important carrier for nanoplastics, which could elicit unintended impacts on critical microbial processes. However, the long-term impacts of nanoplastics on anaerobic granular sludge (AGS) for methane recovery from wastewater and the mechanisms involved remains unclear. In this study, we investigated the long term exposure-response relationship between polystyrene nanoplastics (Nano-PS) and AGS. In continuous test over 120 days with 86 days' Nano-PS exposure, feeding wastewater with 10 μg/L of Nano-PS had no significant impacts on the AGS performance. In comparison, higher levels (i.e., 20 and 50 μg/L) of Nano-PS decreased methane production and chemical oxygen demand (COD) removal by 19.0-28.6% and 19.3-30.0%, respectively, along with volatile fatty acids (VFA) accumulation. More extracellular polymeric substance (EPS) was induced by 10 μg/L of Nano-PS as a response to protect microbes, but higher levels (i.e., 20 and 50 μg/L) of Nano-PS decreased EPS generation, causing a decline in granule size and cell viability. Fluorescence tagging found that a large number of Nano-PS agglomerated/accumulated on the outer layer of AGS and even transferred into deeper layers of AGS over exposure time, producing toxic effects to adherent microorganisms, e.g., Longilinea sp., Paludibacter sp. and Methanosaeta sp.. The oxidative stress induced by Nano-PS was revealed to be a key factor for reshaping the AGS, reflected by the increased reactive oxygen species (ROS) generation and lactate dehydrogenase (LDH) release. The sodium dodecyl sulfate (SDS) leached from Nano-PS was also demonstrated to restrain the activities of antioxidant enzymes, thereby further lessening resistance to oxidative stress induced by Nano-PS. This work improves our ability to predict the risks associated with this ubiquitous contaminant in the environment.
Wei, W, Liu, X, Wu, L, Wang, D, Bao, T & Ni, B-J 2020, 'Sludge Incineration Bottom Ash Enhances Anaerobic Digestion of Primary Sludge toward Highly Efficient Sludge Anaerobic Codigestion', ACS Sustainable Chemistry & Engineering, vol. 8, no. 7, pp. 3005-3012.
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Copyright © 2020 American Chemical Society. In wastewater treatment plants (WWTPs), two main sludge streams, i.e., primary sludge (PS) and waste activated sludge (WAS), are generally mixed for anaerobic codigestion. However, the methane production is usually restricted by the poor and slow biodegradability of PS, and an effective approach for its efficient codigestion with WAS is still lacking due to its highly different sludge properties from those of WAS. Herein, we reported a novel strategy through using the sludge incineration bottom ash to enhance the anaerobic digestion of PS and its codigestion with WAS. Biochemical methane potential (BMP) test results showed that ash additive at 0.6-1.2 g/g-dry matter (DM) significantly enhanced PS anaerobic digestion, identified by an up to 18.2% increase in specific methane production. This was accompanied by a significantly improved dewaterability in the digestate. The transformations of metabolic intermediates revealed that the ash additive accelerated the hydrolysis and acidogenesis processes, which were also supported by the increased hydrolysis rate (k) of PS determined through kinetic modeling. Ash additive was then experimentally demonstrated to be effective in enhancing the anaerobic codigestion of PS and WAS, with the increased volatile solids (VS) destruction being approximately 19.8%, representing a reduction of digestate volume by 12.6%. The novel strategy proposed in this study provides a new paradigm of an integrated sludge-control by sludge to bring significant economic benefits to wastewater treatment and sludge disposal.
Wei, W, Wu, L, Liu, X, Chen, Z, Hao, Q, Wang, D, Liu, Y, Peng, L & Ni, B-J 2020, 'How does synthetic musks affect methane production from the anaerobic digestion of waste activated sludge?', Science of The Total Environment, vol. 713, pp. 136594-136594.
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The increasing use of synthetic musks has led to a large amount of synthetic musks retaining in waste activated sludge (WAS) via wastewater treatment, thereby entering anaerobic digester. However, the potential effects of synthetic musks on WAS anaerobic digestion remain unknown. Herein, this study selected the dominant galaxolide (HHCB) in WAS as the typical synthetic musks and experimentally evaluated the long-term effects on WAS anaerobic digestion using continuous lab-scale anaerobic digesters as well as the mechanisms involved. The results demonstrated that the increased HHCB levels (i.e., 90, 150 and 200 mg/kg-dw) resulted in the decreased methane production, with the methane production at 200 mg/kg-dw being only 80.5 ± 0.1% of the control. Supporting the methane production data, volatile solids (VS) destruction decreased by 18.6 ± 0.9%, which increased 6.8% of volume waste sludge for transfer and disposal. Correspondingly, the microbial community was shifted in the direction against anaerobic digestion. By modeling based on biochemical methane potential tests and investigating the key stages involved in anaerobic digestion, it was found that although the HHCB showed little impacts on the solubilization, WAS hydrolysis-acidification steps was inhibited by HHCB with the decreased hydrolysis rate and methane production potential, thereby causing the deteriorated performance of WAS anaerobic digestion.
Wilkinson, S, Biloria, N & Ralph, P 2020, 'The technical issues associated with algae building technology', International Journal of Building Pathology and Adaptation, vol. 38, no. 5, pp. 673-688.
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PurposeAs the impacts of climate change become more evident, the need to adopt new ways of constructing buildings becomes more urgent. The Earth has experienced hotter climates globally for the last 70 years (NASA, 2019), and this has resulted in unprecedented levels of bushfire in Australia, flooding in the UK and drought in Africa in early 2020 (World Resources Institute, 2019). The predictions are for increased temperatures globally and increasing carbon emissions from fossil fuel consumption. There is a critical need to reduce the reliance on fossil fuels as a building energy source (WCED, 1987). Existing renewables focus on solar, wind and wave power, where technological improvements have increased efficiencies (Hinnells, 2008). Uptake of the technologies is variable depending on location and willingness to adopt renewables. As well as further uptake of existing renewable energy sources, we need to look wider and across traditional discipline groups, at new technologies such as biotechnologies. One potential energy source is biofuels. Biofuels are produced from biomass, which is algae. In 2016, the BIQ, a four-storey apartment building, was constructed in Hamburg, Germany. The BIQ features glazed façade panels filled with algae to produce biomass and solar thermal energy. Could algae building technology (ABT), in the form of façade panels, offer a new renewable energy source?Design/methodology/approachWhat are the technical issues associated with Algae building technology? This qualitative research sought to identify what technical issues likely to arise in terms of algae building construction, operation and maintenance. Semi-structured interviews with 24 experienced built environment professionals in Australia were undertaken in 2016 to assess the most likely issues that cou...
Wu, L, Chen, X, Wei, W, Liu, Y, Wang, D & Ni, B-J 2020, 'A Critical Review on Nitrous Oxide Production by Ammonia-Oxidizing Archaea', Environmental Science & Technology, vol. 54, no. 15, pp. 9175-9190.
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The continuous increase of nitrous oxide (N2O) in the atmosphere has become a global concern because of its property as a potent greenhouse gas. Given the important role of ammonia-oxidizing archaea (AOA) in ammonia oxidation and their involvement in N2O production, a clear understanding of the knowledge on archaeal N2O production is necessary for global N2O mitigation. Compared to bacterial N2O production by ammonia-oxidizing bacteria (AOB), AOA-driven N2O production pathways are less-well elucidated. In this Critical Review, we synthesized the currently proposed AOA-driven N2O production pathways in combination with enzymology distinction, analyzed the role of AOA species involved in N2O production pathways, discussed the relative contribution of AOA to N2O production in both natural and anthropogenic environments, summarized the factors affecting archaeal N2O yield, and compared the distinctions among approaches used to differentiate ammonia oxidizer-associated N2O production. We, then, put forward perspectives for archaeal N2O production and future challenges to further improve our understanding of the production pathways, putative enzymes involved and potential approaches for identification in order to potentially achieve effective N2O mitigations.
Wu, L, Peng, L, Wei, W, Wang, D & Ni, B-J 2020, 'Nitrous oxide production from wastewater treatment: The potential as energy resource rather than potent greenhouse gas', Journal of Hazardous Materials, vol. 387, pp. 121694-121694.
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Nitrous oxide (N2O), produced from wastewater treatment, is a potent greenhouse gas and has become a global concern in recent years. However, N2O has also been commonly used as a powerful oxidant for energy generation. As such, an increasing effort has been devoted to explore the energy potential of N2O from wastewater treatment processes recently. Nevertheless, the holistic knowledge on energy recovery from nitrogen in wastewater is still lacking for facilitating its further development. Striving for sustainable wastewater treatment, this review paper aimed to give the up-to-date status on several essential aspects regarding the N2O recovery as an energy resource rather than emission as a greenhouse gas, including energy production via N2O decomposition, main biotic N2O production sources, the potential bioprocesses used for N2O recovery, and the possible N2O harvesting strategies. We then put forward perspectives for N2O recovery and future challenges to improve our understanding of the energy generation, microbial processes involved and harvesting approaches in order to potentially achieve sustainable wastewater treatment via N2O recovery.
Wu, S-L, Sun, J, Chen, X, Wei, W, Song, L, Dai, X & Ni, B-J 2020, 'Unveiling the mechanisms of medium-chain fatty acid production from waste activated sludge alkaline fermentation liquor through physiological, thermodynamic and metagenomic investigations', Water Research, vol. 169, pp. 115218-115218.
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Effective sludge treatment with bioenergy production is attracting increasing interests as large quantities of waste activated sludge (WAS) are produced during the wastewater treatment. In this study, a new biotechnical process for converting the WAS alkaline fermentation liquor (WASAFL) into valuable, easy-separated medium chain fatty acids (MCFAs) through chain elongation (CE) was investigated, which may provide a new insight into sludge treatment. In the process, ethanol was served as the electron donor (EDs) and WASAFL were main electron acceptors (EAs). The MCFAs productions were investigated under three different ED to EA ratios (i.e., 1:2, 1:1 and 2:1). The result showed that MCFAs production was increased from 2.88 ± 0.01 to 5.28 ± 0.18 g COD/L with the increase of ED to EA ratio. However, the highest MCFA selectivity was achieved at 72.9% when the ED to EA ratio was 1:1. The decrease in the selectivity at high ED:EA ratio is mainly due to the production of higher alcohol (i.e., n-butanol and n-hexanol). The thermodynamic analysis confirmed all CE processes for MCFAs production from WASAFL were exothermic reactions, with the spontaneity and energy release of the reactions increased with the ethanol level. The microbial community analysis showed that the relative abundances of Clostridium, Oscillibacter, Leptolinea and Exilispira were positively correlated with the MCFAs production. The metagenomic analysis suggested that both the reverse β-oxidization pathway and fatty acid biosynthesis pathway contributed to the CE process in the studied system. The functional enzymes were mainly associated within Clostridium, with Clostridium Kluyveri, Clostridium botulinum and Clostridium magnum being likely the key species responsible for the CE process.
Wu, S-L, Wei, W, Sun, J, Xu, Q, Dai, X & Ni, B-J 2020, 'Medium-Chain fatty acids and long-chain alcohols production from waste activated sludge via two-stage anaerobic fermentation', Water Research, vol. 186, pp. 116381-116381.
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Traditional bioenergy recovery in the form of short chain fatty acids (SCFAs) from waste activated sludge (WAS) is generally limited by economic unattractiveness and complexity of products separation. Herein, a novel biotechnology process of two-stage anaerobic fermentation for converting the WAS into high energy density, easy-separated medium chain fatty acids (MCFAs) and long-chain alcohols (LCAs) was evaluated. In this process, the WAS was first converted to WAS alkaline fermentation liquid (WASAFL), serving as electron acceptors (EAs) and inoculum, then adding ethanol as electron donor (ED) for chain elongation (CE). The co-production of MCFAs and LCAs during CE were studied under three different ED to EA ratios, i.e., 3:1, 4:1 and 5:1. Experimental results demonstrated that when the ratio of ED to EA increased from 3:1 to 5:1, the production of MCFA and LCAs respectively increased from 5.57 ± 0.17 and 2.58 ± 0.18 to7.67 ± 0.48 and 4.21 ± 0.19 g COD/L. A similar observation was made in the total product electron efficiency, increasing from 59.9% to 72.1%. However, the highest total product selectivity (i.e., 68.0%) and highest products production yield (i.e., 59.77%) were not achieved at the ED to EA ratio of 5:1 due to toxicity caused by higher accumulation of n-caproate. The kinetic analysis further confirmed that high ratio of ED to EA induced improvement in product maximum yield, production rate for both MCFAs and LCAs. Microbial community analysis indicated that Clostridium, Caproiciproducens, Acinetobacter, Exilispira, and Oscillibacter were clearly enriched in the CE reactor and had positive correlation with MCFAs and LCAs production.
Xie, S, Li, X, Wang, C, Kulandaivelu, J & Jiang, G 2020, 'Enhanced anaerobic digestion of primary sludge with additives: Performance and mechanisms', Bioresource Technology, vol. 316, pp. 123970-123970.
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Anaerobic digestion of primary sludge with different additives, namely nano magnetite, graphite powder, activated carbon powder and NiCl2/CoCl2, were evaluated by biomethane potential tests, kinetics modelling and microbial community analysis. Specific methane yields increased from 136 mL/g VS for primary sludge to 146 mL/g VS, 151 mL/g VS, and 152 mL/g VS for the addition of nano magnetite, graphite powder, and activated carbon powder at optimal dosages, respectively. The first order hydrolysis constant kh increased from 0.488 d-1 to 0.526 d-1, 0.622 d-1, and 0.724 d-1, respectively. Microbial community analysis revealed that the abundance of key bacterial and archaeal populations was positively correlated with hydrolysis and methane production. The enhanced methane production with activated carbon powder was due to shifting methane formation pathway from acetoclastic to hydrogenotrophic methanogenesis. In contrast, nano magnetite and graphite powder additives enhanced the direct interspecies electron transfer evidenced by increased abundance of Methanosaeta and Methanolinea.
Xie, S, Xia, R, Chen, Z, Tian, J, Yan, L, Ren, M, Li, Z, Zhang, G, Xue, Q, Yip, H-L & Cao, Y 2020, 'Efficient monolithic perovskite/organic tandem solar cells and their efficiency potential', Nano Energy, vol. 78, pp. 105238-105238.
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Xu, B, Ahmed, MB, Zhou, JL & Altaee, A 2020, 'Visible and UV photocatalysis of aqueous perfluorooctanoic acid by TiO2 and peroxymonosulfate: Process kinetics and mechanistic insights', Chemosphere, vol. 243, pp. 125366-125366.
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© 2019 Elsevier Ltd The global occurrence and adverse environmental impacts of perfluorooctanoic acid (PFOA) have attracted wide attention. This study focused on the PFOA photodegradation by using photocatalyst TiO2 with peroxymonosulfate (PMS) activation. Aqueous PFOA (50 mg L−1) at the pH 3 was treated by TiO2/PMS under 300 W visible light (400–770 nm) or 32 W UV light (254 nm and 185 nm). The addition of PMS induced a significant degradation of PFOA under powerful visible light compared with sole TiO2. Under visible light, 0.25 g L−1 TiO2 and 0.75 g L−1 PMS in the solution with the initial pH 3 provided optimum condition which achieved 100% PFOA removal within 8 h. Under UV light irradiation at 254 nm and 185 nm wavelength, TiO2/PMS presented excellent performance of almost 100% removal of PFOA within 1.5 h, attributed to the high UV absorbance by the photocatalyst. The intermediates analysis showed that PFOA was degraded from a long carbon chain PFOA to shorter chain intermediates in a stepwise manner. Furthermore, scavenger experiments indicated that SO4•–radicals from PMS and photogenerated holes from TiO2 played an essential role in degrading PFOA. The presence of organic compounds in real wastewater reduced the degradation efficacy of PFOA by 18–35% in visible/TiO2/PMS system. In general, TiO2/PMS could be an ideal and effective photocatalysis system for the degradation of PFOA from wastewater using either visible or UV light source.
Xu, B, Zhou, JL, Altaee, A, Ahmed, MB, Johir, MAH, Ren, J & Li, X 2020, 'Improved photocatalysis of perfluorooctanoic acid in water and wastewater by Ga2O3/UV system assisted by peroxymonosulfate', Chemosphere, vol. 239, pp. 124722-124722.
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© 2019 Elsevier Ltd Perfluorooctanoic acid (PFOA) has attracted considerable attention worldwide due to its widespread occurrence and environmental impacts. This research focused on the photocatalytic process for the treatment of PFOA in water and wastewater. Gallium oxide (Ga2O3) and peroxymonosulfate (PMS) were mixed directly in PFOA solution, which was irradiated under different light sources. The treatment system showed excellent performance that 100% PFOA was degraded within 90 min and 60 min under 254 nm and 185 nm UV irradiation, respectively. Moreover, the degradation efficacy was unaffected by initial PFOA concentration from 50 ng L−1 to 50 mg L−1. Acidic solution (pH 3) improved the degradation process. The quantum yield in the PMS/Ga2O3 system under UV light (254 nm) was estimated to be 0.009 mol E−1. Scavengers such as tert-butanol (t-BuOH), disodium ethylenediaminetetraacetate (EDTA-Na2) and benzoquinone (BQ) were added into PFOA solution to prove that sulfate radicals (SO4•–), superoxide radical (O2•–) and photogenerated electrons (e–) were the main active species with strong redox ability for PFOA degradation in PMS/Ga2O3/UV system. Combined with the intermediates analysis, PFOA was degraded stepwise from long chain compound to shorter chain intermediates. In addition, PFOA in real wastewater exhibited similar degradation efficiency, together with 75–85% TOC removal by Ga2O3/PMS under 254 nm UV irradiation. Therefore, Ga2O3/PMS system was highly effective for PFOA photodegradation under UV irradiation, which has potential to be applied for the perfluoroalkyl substances (PFAS) treatment in water and wastewater.
Xu, D-S, Xu, X-Y, Li, W & Fatahi, B 2020, 'Field experiments on laterally loaded piles for an offshore wind farm', Marine Structures, vol. 69, pp. 102684-102684.
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© 2019 Elsevier Ltd Pile foundations are widely used to support offshore wind turbines due to their cost effectiveness and rapid constructions. Offshore piles must be designed with enough capacity to withstand overturning moments caused by wind turbines and other environmental factors such as wave excitations and extreme winds. In this study, a full-scale field experimental test is undertaken to determine the pile behaviour under various lateral loading conditions. A distributed fiber optic sensing technology is used to measure strains along two instrumented piles. The bending moments and lateral deflections are calculated from distributed fiber optic sensors, and then analysed with the various p-y methods. Field measurements indicated that for two offshore piles ZK01 and ZK28 with diameter of 2 m and length of 71.5 m and 77.5 m, the maximum lateral movements under a given lateral load of 800 kN were 369.1 mm and 351.7 mm, respectively. The maximum bending moment occurred at 6.5 m and 5.5 m below seabed level with the corresponding depth of 12.15D and 11.95D for pile ZK01 and ZK28, respectively. The position of “zero crossing” of soil resistance for two instrumented piles is almost the same, even though the piles have different lengths. The lateral deflections and bending moments of the two instrumented piles are predicted by the API and hyperbolic method, which indicates that the hyperbolic method yields larger prediction errors than the API method. A modified p-y approach is then proposed for more reliable predictions when compared with field measurements.
Xu, Q, Du, M, Liu, X, Wang, D, Wu, Y, Li, Y, Yang, J, Fu, Q, He, D, Feng, C, Liu, Y, Wang, Q & Ni, B-J 2020, 'Calcium peroxide eliminates grease inhibition and promotes short-chain fatty acids production during anaerobic fermentation of food waste', Bioresource Technology, vol. 316, pp. 123947-123947.
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Deterioration of anaerobic fermentation can occur with the presence of grease in food waste, but little information on eliminating this deterioration is currently available. In this study, it was found that the presence of 10 g/L grease decreased SCFAs production from 16.97 to 13.32 g COD/L and prolonged the optimal fermentation time to 7 days, but could be respectively recovered to 39.10 g COD/L and 4 days with 0.02 mg/g VS (volatile solids) calcium peroxide addition. Mechanism investigations indicated that calcium peroxide facilitated biodegradable organics release and improved grease degradation, thereby providing enough nutrients and better growth environments to microbes for SCFAs-producing, which could be further supported by the elevated enzymes activities responding to hydrolysis and acidification process. Further investigations revealed that among the main derivates of calcium peroxide, OH- and Ca2+ played vital role in SCFAs production promotion, O2- and OH radicals were the main contributors to grease degradation.
Xu, Q, Huang, Q-S, Wei, W, Sun, J, Dai, X & Ni, B-J 2020, 'Improving the treatment of waste activated sludge using calcium peroxide', Water Research, vol. 187, pp. 116440-116440.
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The treatment and disposal of waste activated sludge (WAS) has become one of the major challenges for the wastewater treatment plants (WWTPs) due to large output, high treatment costs and enriched substantial emerging contaminants (ECs). Therefore, reducing sludge volume, recovering energy and resource from WAS, and removing ECs and decreasing environmental risk have gained increasing attentions. Calcium peroxide (CaO2), a versatile and safe peroxide, has been widely applied in terms of WAS treatment including sludge dewatering, anaerobic sludge digestion and anaerobic sludge fermentation due to its specific properties such as generating free radicals and alkali, etc., providing supports for sludge reduction, recycling, and risk mitigation. This review outlines comprehensively the recent progresses and breakthroughs of CaO2 in the fields of sludge treatment. In particular, the relevant mechanisms of CaO2 enhancing WAS dewaterability, methane production from anaerobic digestion, short-chain fatty acids (SCFA) and hydrogen production from anaerobic fermentation, and the removal of ECs in WAS and role of experiment parameters are systematically elucidated and discussed, respectively. Finally, the knowledge gaps and opportunities in CaO2-based sludge treatment technologies that need to be focused in the future are prospected. The review presented can supply a theoretical basis and technical reference for the application of CaO2 for improving the treatment of WAS.
Xu, Q, Liu, X, Yang, G, Wang, D, Wu, Y, Li, Y, Huang, X, Fu, Q, Wang, Q, Liu, Y, Li, X & Yang, Q 2020, 'Norfloxacin-induced effect on enhanced biological phosphorus removal from wastewater after long-term exposure', Journal of Hazardous Materials, vol. 392, pp. 122336-122336.
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In this study, long-term experiments were performed under synthetic wastewater conditions to evaluated the potential impacts of norfloxacin (NOR) (10, 100 and 500 μg/L) on enhanced biological phosphorus removal (EBPR). Experimental result showed that long-term exposure to 10 μg/L NOR induced negligible effects on phosphorus removal. The presence of 100 μg/L NOR slightly decreased phosphorus removal efficiency to 94.41 ± 1.59 %. However, when NOR level further increased to 500 μg/L, phosphorus removal efficiency was significantly decreased from 97.96 ± 0.8 5% (control) to 82.33 ± 3.07 %. The mechanism study revealed that the presence of 500 μg/L NOR inhibited anaerobic phosphorus release and acetate uptake as well as aerobic phosphorus uptake during long-term exposure. It was also found that 500 μg/L NOR exposure suppressed the activity of key enzymes related to phosphorus removal but promoted the transformations of intracellular polyhydroxyalkanoate and glycogen. Microbial analysis revealed that that the presence of 500 μg/L NOR reduced the abundances of polyphosphate accumulating organisms but increased glycogen accumulating organisms, as compared the control.
Xu, Y, Peng, L, Liu, Y, Xie, G, Song, S & Ni, B-J 2020, 'Modelling melamine biodegradation in a membrane aerated biofilm reactor', Journal of Water Process Engineering, vol. 38, pp. 101626-101626.
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© 2020 Elsevier Ltd Membrane aerated biofilm reactor (MABR) system is excellent in developing slow growing microorganisms and treating micropollutants prior to entering the aquatic environment. In this work, a mathematical biofilm model was developed to assess melamine biodegradation under different conditions and to predict the profiles of melamine, nitrogen species and microbial biomass in the MABR system. Comtabolism linked to growth of ammonia oxidizing bacteria (AOB) or heterotrophic bacteria (HB) and their respective metabolism were involved in the model to contribute to melamine biodegradation. Results demonstrated the good predictive performance of the developed model in describing dynamic profiles of melamine, COD and nitrogen species in the MABR system. The relative contribution by AOB-induced cometabolism and metabolism by AOB and HB varied depending on the stratification of the biofilm system with AOB prevalent in the inner layer of the biofilm. Metabolism by AOB and HB played more important roles than AOB-induced cometabolism in melamine removal. Controlling optimal biofilm thickness in the suitable range (e.g., more than 750 μm) might realize better simultaneous removal of melamine and nitrogen. This work might provide further insight on efficient removal of melamine from wastewater.
Yadav, S, Ibrar, I, Altaee, A, Déon, S & Zhou, J 2020, 'Preparation of novel high permeability and antifouling polysulfone-vanillin membrane', Desalination, vol. 496, pp. 114759-114759.
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A novel high-performance nanofiltration membrane was fabricated by a simple and scalable route involving in situ cross-linking of hydrophilic, cheap, and environmentally friendly vanillin as antifouling agent with polysulfone (PSf) for salt rejection performance. Vanillin acts as a porogen, which induces a negative surface charge on the membrane surface due to the presence of polar functional groups like alcohol and aldehyde. The surface properties, including charge, morphology, and hydrophilicity, were investigated in detail using analytical instruments. The nanofiltration performance of the fabricated PSf-vanillin membranes was dependent on the percentage of vanillin added in the casting solution. The PSf-vanillin membrane antifouling tests were evaluated using 200 mg/L bovine serum albumin (BSA), and results showed 99% rejection with 88.55% flux recovery ratio. Performance studies were compared with commercially available TRISEP® UA60 nanofiltration membrane. PSf-vanillin membrane M2 showed higher MgSO4 (87.49%), NaCl (25.78%) rejection with excellent antifouling properties compared to commercial UA60 membrane. It is believed that charged membranes are the building blocks for the development of future generation desalination membranes possessing high permeability and selectivity index. The developed membranes have potential niche application in the pre-treatment of feed solution.
Yadav, S, Ibrar, I, Altaee, A, Samal, AK, Ghobadi, R & Zhou, J 2020, 'Feasibility of brackish water and landfill leachate treatment by GO/MoS2-PVA composite membranes', Science of The Total Environment, vol. 745, pp. 141088-141088.
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Two-dimensional (2D) based layered materials with tunable chemical functionalities and surface charge properties have emerged for on-demand applications including membrane technology. However, the process control, time and energy-efficient production of non-swelling graphene oxide (GO) with retaining physicochemical properties are still challenging. In this work, we have fabricated highly ordered GO membrane on cellulose acetate supporting membrane filters of 1.2 μm pore size using molybdenum disulphide (MoS2) as a nano-spacer and polyvinyl alcohol (PVA) as an adhesive for the first time with limited swelling. The fabricated membranes were used for NaCl rejection and removal of toxic heavy metal ions, and the radioactive element from landfill leachate water. The introduction of hydrophilic PVA, thickness control using a various amount of nanospacer and graphene oxide played a vital role in the transport mechanism, permeability, and selectivity index. The composition of PVA and MoS2 in the coating solution was optimized to tune the d-spacing of graphene oxide layers. The newly developed composite membranes have 89% rejection rate to NaCl and 3.96 L/m2h water flux at low operating pressures of 5 bar. Also, the prepared membranes have a high rejection of multivalent metal ions in landfill leachate. 86.5% to 99.8% rejection rate of multivalent metal ions in landfill leachate was observed for the M3 (GO (10): MoS2 (10): PVA (0.5)) membrane. The excellent rejection performance is ascribed to the combined impact of size exclusion, ion adsorption, electrostatic interaction and Gibbs-Donnan exclusion mechanism. The excellent stability and high rejection rate even after 216 h of operation make the fabricated membranes promising for use in practical water separation applications.
Yadav, S, Ibrar, I, Bakly, S, Khanafer, D, Altaee, A, Padmanaban, VC, Samal, AK & Hawari, AH 2020, 'Organic Fouling in Forward Osmosis: A Comprehensive Review', Water, vol. 12, no. 5, pp. 1505-1505.
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Organic fouling in the forward osmosis process is complex and influenced by different parameters in the forward osmosis such as type of feed and draw solution, operating conditions, and type of membrane. In this article, we reviewed organic fouling in the forward osmosis by focusing on wastewater treatment applications. Model organic foulants used in the forward osmosis literature were highlighted, which were followed by the characteristics of organic foulants when real wastewater was used as feed solution. The various physical and chemical cleaning protocols for the organic fouled membrane are also discussed. The study also highlighted the effective pre-treatment strategies that are effective in reducing the impact of organic fouling on the forward osmosis (FO) membrane. The efficiency of cleaning methods for the removal of organic fouling in the FO process was investigated, including recommendations on future cleaning technologies such as Ultraviolet and Ultrasound. Generally, a combination of physical and chemical cleaning is the best for restoring the water flux in the FO process.
Yadav, S, Saleem, H, Ibrar, I, Naji, O, Hawari, AA, Alanezi, AA, Zaidi, SJ, Altaee, A & Zhou, J 2020, 'Recent developments in forward osmosis membranes using carbon-based nanomaterials', Desalination, vol. 482, pp. 114375-114375.
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© 2020 Elsevier B.V. Contamination and industrial development are among the reasons for water quality deterioration beyond treatability by conventional processes. Unfortunately, conventional water and wastewater treatment technologies are not always capable of handling industrial wastewaters, and hence more advanced treatment technologies are required. The new trend of osmotically driven membrane technologies has demonstrated an exceptional efficiency for water purification and treatment including seawater desalination. Compared to pressure-driven membrane processes, forward osmosis (FO) technology, as a standalone process, is more energy-efficient, and less prone to membrane fouling than its predecessor reverse osmosis (RO) technology. However, forward osmosis suffers a severe concentration polarization that is acting on both sides of the membrane and results in a sharp decline in water flux. A thinner support layer has been recommended to lessen the concentration polarization impact in the FO process but a very thin support layer compromises the membrane mechanical strength. Recently, researchers have applied different carbon-based nanomaterials to enhance water flux, fouling propensity, and mechanical strength of the FO membrane. This work reviews advancement in the FO membrane fabrication using carbon nanomaterials to improve the membrane characteristics. Despite a large number of laboratory experiments, carbon-based nanomaterials in the FO membrane are still at the early-stage of laboratory investigation and no commercial products are available yet. The study also reviews the main challenges that limit the application of carbon-based nanomaterials for FO membranes.
Yan, X, Sun, J, Kenjiahan, A, Dai, X, Ni, B-J & Yuan, Z 2020, 'Rapid and strong biocidal effect of ferrate on sulfidogenic and methanogenic sewer biofilms', Water Research, vol. 169, pp. 115208-115208.
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For the control of sulfide and methane in sewers, it is favorable to reduce their production rather than to remove them after generation. In this study, we revealed rapid and strong biocidal effect of ferrate (Fe(VI)) on sulfidogenic and methanogenic sewer biofilms, leading to control of sulfide and methane production in sewer. The inactivation of the microorganisms in sewer biofilms by Fe(VI) could be accomplished within 15 min for a single dosing event and the biocidal effect could be enhanced by applying pulse dosing strategy. The microbiological analysis showed that the key functional genes involved in sulfide and methane production, i.e. dsrA and mcrA, in the viable cells after Fe(VI) dosing were decreased substantially by 84.2% and 86.6%, respectively. Significant drops were also observed in the relative abundances of viable sulfide reducing bacteria (SRB) and methanogenic archaea (MA). The direct dosing of Fe(VI) into a sewer reactor led to instant and complete suppression of sulfidogenic and methanogenic activities, and the recovery of the activities resembled the regrowth of residual SRB and MA. The results of this study suggested the feasibility for developing an efficient and cost-effective sulfide and methane control strategy using Fe(VI).
Yang, G, Zhang, N, Yang, J, Fu, Q, Wang, Y, Wang, D, Tang, L, Xia, J, Liu, X, Li, X, Yang, Q, Liu, Y, Wang, Q & Ni, B-J 2020, 'Interaction between perfluorooctanoic acid and aerobic granular sludge', Water Research, vol. 169, pp. 115249-115249.
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The increasing use of perfluorooctanoic acid (PFOA) raises concerns about its potential toxicity to the environment. However, the interaction between PFOA and aerobic granular sludge has never been documented. This work therefore aims to provide such support through investigating the fate of PFOA at environmentally relevant levels in aerobic granular sludge systems and its impact on aerobic granular sludge. Experimental results showed that 32.0%∼36.4% of wastewater PFOA was removed by aerobic granular sludge in stable operation when PFOA concentration was ranged from 0.1 to 1.0 mg/L. Mass balance analyses and X-ray photoelectron spectroscopy survey scan revealed that the removal of PFOA was dominated by adsorption rather than biodegradation, and sorption kinetic analysis indicated that inhomogeneous multilayer adsorption was responsible for this removal. The adsorbed PFOA deteriorated the settleability of granular sludge and biological nitrogen and phosphorus removal significantly. Experimental results showed that 1.0 mg/L PFOA inhibited anaerobic phosphate release, aerobic phosphate uptake, nitrate reduction, and nitrite reduction processes by 60%, 50%, 13.1%, and 5.8%, respectively. It was observed that PFOA induced large amounts of filamentous villus growing on the surface and increased the extracellular polymeric substances of granular sludge. Fourier-transform infrared spectra and X-ray photoelectron spectroscopy spectrum showed that several function groups in extracellular polymeric substances such as hydroxyl groups, amides and polysaccharides were affected by PFOA. It was also found that PFOA inhibited the cyclic transformations of polyhydroxyalkanoates and glycogen. Microbial community analyses showed that PFOA decreased the abundances of Nitrosomonas, Nitrospira, Accumulibacter, and other function microbes such as Rhodospirillaceae, Thauera, and Azoarcus.
Yang, J, Liu, X, Liu, X, Xu, Q, Wang, W, Wang, D, Yang, G, Fu, Q, Kang, Z, Yang, Q, Liu, Y, Wang, Q & Ni, B-J 2020, 'Enhanced dark fermentative hydrogen production from waste activated sludge by combining potassium ferrate with alkaline pretreatment', Science of The Total Environment, vol. 707, pp. 136105-136105.
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© 2019 Alkaline pretreatment was demonstrated to be effective in the enhancement of hydrogen production. However, the sludge solubilization rate of alkaline pretreatment is still limited. This study reports a new strategy of K2FeO4 + pH 9.5 for sludge mesophilic anaerobic fermentation. Experimental results showed that the combination of K2FeO4/pH 9.5 pretreatment had a greater hydrogen yield than the individual K2FeO4 and pH 9.5. The maximum hydrogen yield was 19.2 mL per gram volatile suspended solids (VSS) under the optimal condition (0.02 g per gram total suspended solids K2FeO4 + pH 9.5). Kinetic analysis showed that the highest hydrogen production potential of 19.9 mL/g VSS was obtained in the combined reactor, which well fitted the first-order kinetic model (R2 = 0.9925). Besides, the fermentation type was mainly acetic and butyric in the combined reactor, which contributed to hydrogen production. Further analyses showed that the combined pretreatment reduced hydrogen sulfide yield, providing an environmentally friendly method to sludge treatment.
Yang, Y, Liu, Y, Fang, X, Miao, W, Chen, X, Sun, J, Ni, B-J & Mao, S 2020, 'Heterogeneous Electro-Fenton catalysis with HKUST-1-derived Cu@C decorated in 3D graphene network', Chemosphere, vol. 243, pp. 125423-125423.
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Transition metal and nanocarbon-based composites with high activity and stability draw great attention in electro-Fenton system for organic pollutants removal. In this study, HKUST-1-derived Cu@C nanoparticles embedded within three-dimensional reduced graphene oxide (rGO) network (denoted as 3DG/Cu@C) is synthesized through a simple strategy. The prepared catalyst shows ordered 3D porous carbon structure and Cu@C NPs are uniformly dispersed in the matrix. The 3DG/Cu@C is used as heterogeneous electro-Fenton (hetero-EF) catalyst and shows outstanding performance in various persistent organic pollutants removal. High concentration Rhodamine B (RhB) (40 mg L-1) can achieve a complete decolorization within 150 min with 25 mg L-1 3DG/Cu@C catalyst, which is one of the lowest catalyst dosages in hetero-EF for RhB removal. More importantly, the 3DG/Cu@C achieves high RhB mineralization efficiency of 81.5% and exhibits high catalytic performance in a wide pH window from 3 to 9. The 3DG/Cu@C also remains high efficiency after five successive reaction cycles. The working mechanism study shows that RhB is mainly oxidized by •OH and O2•- radicals through hetero-EF and anodic oxidation processes. The high stability and outstanding performance of 3DG/Cu@C provide new insights in organic pollutants removal by hetero-EF process with transition metal and nanocarbon-based catalysts.
Yang, Y, Zang, Y, Hu, Y, Wang, XC & Ngo, HH 2020, 'Upflow anaerobic dynamic membrane bioreactor (AnDMBR) for wastewater treatment at room temperature and short HRTs: Process characteristics and practical applicability', Chemical Engineering Journal, vol. 383, pp. 123186-123186.
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© 2019 Elsevier B.V. An upflow anaerobic dynamic membrane bioreactor (AnDMBR) was set up for real domestic wastewater treatment at room temperature (20–25 °C) and short hydraulic retention time (HRT = 8 h, 4 h, 2 h, and 1 h). Following continuous operation for 93 days with stepwise decreased HRT, stable average chemical oxygen demand (COD) removal was achieved (between 77.3% and 70.6%) when HRT was reduced from 8 h to 4 h, then 2 h with flux varying from 22.5 to 90 L/m2·h. At these three HRTs, the rate of increase in trans-membrane pressure (TMP) was 0.4, 0.38, and 0.57 kPa/d, and average methane (CH4) production was 0.12, 0.10, and 0.08 L/g CODremoved, respectively. Furthermore, decreasing the HRT to 1 h resulted in less COD being removed (60.4%) and lower CH4 production (0.05 L/g CODremoved) as well as a faster rate of TMP increase (2.11 kPa/d). Various analytical methods were applied to characterize the morphology and composition of the dynamic membrane (DM) layers. Organic components analysis revealed that, with reduced HRT, there were apparent increases in soluble microbial products in the liquid phase and accumulation of tryptophan protein-like substances and aromatic protein-like substances in the DM layer, especially when the HRT was shortened to 1 h. Whilst the upflow AnDMBR proved applicable to wastewater treatment at room temperature with short HRTs, 2 h could be the HRT limit for maintaining stable operation.
Yao, M, Tijing, LD, Naidu, G, Kim, S-H, Matsuyama, H, Fane, AG & Shon, HK 2020, 'A review of membrane wettability for the treatment of saline water deploying membrane distillation', Desalination, vol. 479, pp. 114312-114312.
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© 2020 Elsevier B.V. Membrane distillation (MD) is an alternative membrane technology that offers the capacity to treat highly saline water including industrial wastewater, seawater, brine water from other processes, and oil-gas field produced water. However, conventional hydrophobic membranes suffer fast wetting and severe fouling especially when low surface tension chemicals exist in saline water, which compromises the performance of MD. Recent advances in material science and nanomaterials research have led to the incorporation of special wetting properties on membrane surfaces. Membranes with special wettability can achieve high resistance against membrane fouling and wetting, as well as overcome the trade-off between membrane permeability and selectivity. This review summarizes the progress and recent development of studies on MD membranes with special wettability. Firstly, the fundamental concepts pertaining to membrane surface wettability including insights of their benefits and potential issues are highlighted in this review. Secondly, fabrication methods and applications of membranes utilizing various special wettability are discussed in detail, along with their challenges. Finally, this review concludes the advantages of membranes with special wettability and demonstrates potential solutions to the above-mentioned challenges for future research in high saline wastewater treatment.
Ye, Y, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Zhang, X, Zhang, J & Liang, S 2020, 'Nutrient recovery from wastewater: From technology to economy', Bioresource Technology Reports, vol. 11, pp. 100425-100425.
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© 2020 Elsevier Ltd The recovery of fertilizer-used nutrients from wastewater is a sustainable approach for wastewater management and helping social sustainability. This is especially the case given the strict discharge requirements and shortages existing in nutrients supply. Recognizing that wastewater is a very useful resource and the value of recycled nutrients has made researchers consider the recovery of nutrients from wastewater. This review described the current technologies used to recover nutrients in wastewater treatment and their mechanisms, including chemical methods, biological technologies, membrane systems and advanced membrane systems. Also, an economic analysis of these nutrient recovery systems was discussed and compared them in terms of positive and negative aspects. The economic feasibility of recovered nutrients was investigated. Finally, future perspectives expects some possible research directions regarding recovery system which can be more economically accessible for wastewater treatment, in which the osmotic membrane bioreactors (OMBR) and bioelectrochemical systems (BES)-based hybrid systems are highly recommended.
Ye, Y, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Zhang, X, Zhang, S, Luo, G & Liu, Y 2020, 'Impacts of hydraulic retention time on a continuous flow mode dual-chamber microbial fuel cell for recovering nutrients from municipal wastewater', Science of The Total Environment, vol. 734, pp. 139220-139220.
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Zang, Y, Yang, Y, Hu, Y, Ngo, HH, Wang, XC & Li, Y-Y 2020, 'Zero-valent iron enhanced anaerobic digestion of pre-concentrated domestic wastewater for bioenergy recovery: Characteristics and mechanisms', Bioresource Technology, vol. 310, pp. 123441-123441.
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Pre-concentrated domestic wastewater (PDWW) rich in organic matters can be a suitable substrate for anaerobic digestion (AD) towards holistic resource and bioenergy recovery. Micron zero-valent iron (ZVI) was applied in designed batch experiments during anaerobic treatment of PDWW to verify its roles in performance enhancement and associated mechanisms. In the selected range of food to microorganism (F/M) ratio, 0.5 gCOD/gMLVSS was most appropriate as biomethane production potential (BMP) of 0.275 L CH4/gCOD was obtained. The optimal ZVI dosage at fixed F/M of 0.5 was 6 g/L, further enhancing the BMP by 15.2%. Furthermore, ZVI improved the hydrolysis process (producing more soluble organics) and regulated acidification process (affecting volatile fatty acids distribution). No obvious impact on acetoclastic and hydrogenotrophic methanogenesis processes was noted with ZVI addition. ZVI based AD of the PDWW is promising for promoting the practical application of advanced domestic wastewater treatment strategy (pre-concentration plus anaerobic digestion).
Zeweldi, HG, Bendoy, AP, Park, MJ, Shon, HK, Kim, H-S, Johnson, EM, Kim, H, Lee, S-P, Chung, W-J & Nisola, GM 2020, 'Tetrabutylammonium 2,4,6-trimethylbenzenesulfonate as an effective and regenerable thermo-responsive ionic liquid drawing agent in forward osmosis for seawater desalination', Desalination, vol. 495, pp. 114635-114635.
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© 2020 Elsevier B.V. Efficient drawing agents are essential in forward osmosis (FO) for clean water production. Monomeric thermo-responsive ionic liquid (IL) [N4444]2,4,6-MeBnSO3 was thoroughly investigated as a drawing agent in FO. The IL can be safely employed due to its thermal stability and low cytotoxicity. It has a van't Hoff factor i = 1.21, with sufficient ionic strength to generate osmotic pressure ~ 58.92 bars (2 M). FO operations especially under PRO mode demonstrate that 2 M [N4444]2,4,6-MeBnSO3 can induce competitive water flux Jv ~ 12.3 L m−2 h−1 with remarkably low reverse solute flux Js < 0.006 mol m−2 h−1 and specific reverse solute flux Js/Jv ~ 4.5 × 10−4 mol L−1. Using 0.6 M NaCl as feed demonstrates its consistency in desalinating seawater (Jv ~ 3.72 L m−2 h−1, Js ~ 0.004 mol m−2 h−1, and Js/Jv ~ 0.91 × 10−3 mol L−1). After FO, [N4444]2,4,6-MeBnSO3 can be effectively retrieved (~98%) through thermal precipitation at 60 °C, above its cloud point temperature (57 °C). Meanwhile, >99% of the remaining 2% can be recovered through reverse osmosis or membrane distillation to produce water effluents with non-toxic IL concentrations (≪100 mg L−1). Results indicate that thermo-responsive [N4444]2,4,6-MeBnSO3 is a promising alternative reusable drawing agent in FO process.
Zhang, L, Chen, Y, Ma, C, Liu, L, Pan, J, Li, B, Wu, X & Wang, Q 2020, 'Improving heavy metals removal, dewaterability and pathogen removal of waste activated sludge using enhanced chemical leaching', Journal of Cleaner Production, vol. 271, pp. 122512-122512.
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© 2020 In order to enhance heavy metals removal, two enhanced chemical leaching techniques were examined comparatively using NaClO and NaNO2 with the addition of FeCl3. The phosphorus release, dewaterability and pathogen removal of treated sludge were also examined after chemical leaching. The results showed that the heavy metals solubilization, improvement of dewaterability and pathogen removal were simultaneously achieved. Compared with NaClO treatment system, the better solubilization rates of Zn and Ni were observed in the NaNO2 treatment system. The improvement of Cu, Zn and Ni removal can be attributed to the disruption of the organically bound metal fraction based on metal distribution and EEM analysis. The TP loss caused by chemical leaching in this study was in the range of 47 %–54%. The treated sludge of the two systems could both meet Class A biosolids standards (US EPA) for land application. These results provided an alternative chemical leaching method for simultaneous improvement of sludge properties.
Zhang, S, Ly, QV, Nghiem, LD, Wang, J, Li, J & Hu, Y 2020, 'Optimization and organic fouling behavior of zwitterion-modified thin-film composite polyamide membrane for water reclamation: A comprehensive study', Journal of Membrane Science, vol. 596, pp. 117748-117748.
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© 2019 Membrane fouling can hinder the widespread application of thin film composite (TFC) reverse osmosis (RO) for water treatment. This study evaluated a novel zwitterion-grafted TFC RO as a mean to address organic fouling for water reclamation. The membrane exhibited the best permeability at the grafting condition of 45 °C in 1 h. This modified membrane consistently possessed improved antifouling ability irrespective of organic foulants. Among individual foulants, surfactant Dodecyl Trimethyl Ammonium Chloride (DTAC) posed the worst fouling potential due to its low molecular weight and positive charge, whereas fouling induced by other substances were relatively analogous and minor. In the mixture of DTAC and proteins, the former played a key role in governing the membrane fouling. While, their interplay affected membrane fouling, the fouling extent varied upon the membrane materials. The extended Derijaguin, Landau, Verwey and Overbeek (xDLVO) theory was unable to fully describe the interactions between surfactant foulants and the membrane materials. The complementary use of quartz crystal microbalance with dissipation (QCM-D), otherwise, concurred the fouling potential and gave the plausible interpretation for fouling mechanisms by providing insightful information of foulant layer on the polyamide-coated sensor. This study provided critical insights of organic foulants’ behavior on TFC RO membrane and offered the promising industrial implication of the novel membrane.
Zhang, X, Song, Z, Hao Ngo, H, Guo, W, Zhang, Z, Liu, Y, Zhang, D & Long, Z 2020, 'Impacts of typical pharmaceuticals and personal care products on the performance and microbial community of a sponge-based moving bed biofilm reactor', Bioresource Technology, vol. 295, pp. 122298-122298.
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Four lab-scale moving bed biofilm reactors (MBBRs) were built to treat simulated wastewater containing typical pharmaceuticals and personal care products (PPCPs). The efficiency in removing different PPCPs at different concentrations (1, 2 and 5 mg/L) and their effects on the performance of MBBRs were investigated. Results showed that the average removal efficiencies of sulfadiazine, ibuprofen and carbamazepine were 61.1 ± 8.8%, 74.9 ± 8.8% and 28.3 ± 7.4%, respectively. Compared to the reactor without PPCPs, the total nitrogen (TN) removal efficiency of the reactors containing sulfadiazine, ibuprofen and carbamazepine declined by 21%, 30% and 42%, respectively. Based on the microbial community analysis, increasing the PPCPs concentration within a certain range (<2 mg/L) could stimulate microbial growth and increase microbial diversity yet the diversity reduced when the concentration (5 mg/L) exceeded the tolerance of microorganisms. Furthermore the presence and degradation of different PPCPs resulted in a different kind of microbial community structure in the MBBRs.
Zhang, X, Zhang, Y, Ngo, HH, Guo, W, Wen, H, Zhang, D, Li, C & Qi, L 2020, 'Characterization and sulfonamide antibiotics adsorption capacity of spent coffee grounds based biochar and hydrochar', Science of The Total Environment, vol. 716, pp. 137015-137015.
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A large amount of spent coffee grounds is produced as a processing waste each year during making the coffee beverage. Sulfonamide antibiotics (SAs) are frequently detected in the environment and cause pollution problems. In this study, biochar (BC) and hydrochar (HC) were derived from spent coffee grounds through pyrolysis and hydrothermal carbonization, respectively. Their characteristics and sulfonamide antibiotics adsorption were investigated and compared with reference to adsorption capacity, adsorption isotherm and kinetics. Results showed BC possessed more carbonization and less oxygen-containing functional groups than HC when checked by Elemental Analysis, X-ray diffraction, X-ray photoelectron spectrometry and Fourier transform infrared. These groups affected the adsorption of sulfonamide antibiotics and adsorption mechanism. The maximum adsorption capacities of BC for sulfadiazine (SDZ) and sulfamethoxazole (SMX) were 121.5 μg/g and 130.1 μg/g at 25 °C with the initial antibiotic concentration of 500 μg/L, respectively. Meanwhile the maximum adsorption capacities of HC were 82.2 μg/g and 85.7 μg/g, respectively. Moreover, the adsorption mechanism for SAs adsorbed onto BC may be dominated by π-π electron donor-acceptor interactions, yet the SAs adsorption to HC may be attributed to hydrogen bonds. Further analysis of the adsorption isotherms and kinetics, found that physical and chemical interactions were involved in the SAs adsorption onto BC and HC. Overall, results suggested that: firstly, pyrolysis was an effective thermochemical conversion of spent coffee grounds; and secondly, BC was the more promising adsorbent for removing sulfonamide antibiotics.
Zhang, X, Zhang, Z, Liu, Y, Hao Ngo, H, Guo, W, Wang, H, Zhang, Y & Zhang, D 2020, 'Impacts of sulfadiazine on the performance and membrane fouling of a hybrid moving bed biofilm reactor-membrane bioreactor system at different C/N ratios', Bioresource Technology, vol. 318, pp. 124180-124180.
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The performance and membrane fouling of a hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) system was evaluated when exposed to 0.5 mg/L of antibiotic sulfadiazine (SDZ). Results indicated that although SDZ reduced the removal efficiency of NH -N and TN (up to 12%) and TOC (up to 6%) at low C/N (2.5 and 4), it had no significant effect at high C/N (6 and 9). It was found that SDZ was removed 75% and 58% at high C/N of 9 and low C/N of 2.5, respectively. SDZ decreased the ratio of volatile biomass/total biomass and sludge particle size and increased the concentrations of extracellular polymeric substance (EPS) and soluble microbial product (SMP) in MBR. Consequently, this accelerated the membrane fouling rates, with an average increase of 6.85 kPa/d at low C/N (2.5) and 0.513–0.701 kPa/d at medium and high C/N (4, 6 and 9). 4 +
Zhang, Y-T, Wei, W, Huang, Q-S, Wang, C, Wang, Y & Ni, B-J 2020, 'Insights into the microbial response of anaerobic granular sludge during long-term exposure to polyethylene terephthalate microplastics', Water Research, vol. 179, pp. 115898-115898.
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The negative effects of ubiquitous microplastics on wastewater treatment have attracted increasing attention. However, the potential impacts of microplastics on anaerobic granular sludge (AGS) remain unknown. To fill this knowledge gap, this paper investigated the response of AGS to the exposure of model microplastics (polyethylene terephthalate (PET-MPs)) and provided insights into the mechanisms involved. The 84 days' long-term exposure experiments demonstrated that PET-MPs, at relatively low level (15 MP L-1) did not affect AGS performance during anaerobic wastewater treatment, while 75-300 MP L-1 of PET-MPs caused the decreases of COD removal efficiency and methane yields by 17.4-30.4% and 17.2-28.4%, accompanied with the 119.4-227.8% increase in short-chain fatty acid (SCFA) accumulation and particle breakage. Extracellular polymeric substances (EPS) analysis showed that dosage-dependent tolerance of AGS to PET-MPs was attributed to the induced EPS producing protection role, but PET-MPs at higher concentrations (75-300 MP L-1) suppressed EPS generation. Correspondingly, microbial community analysis revealed that the populations of key acidogens (e.g., Levilinea sp.) and methanogens (e.g., Methanosaeta sp.) decreased after long-term exposure to PET-MPs. Assessment of the toxicity of PET-MPs revealed that the leached di-n-butyl phthalate (DBP) and the induced reactive oxygen species (ROS) by PET-MPs were causing toxicity towards AGS, confirmed by the increases in cell mortality and lactate dehydrogenase (LDH) release. These results provide novel insights into the ecological risk assessment of microplastics in anaerobic wastewater treatment system.
Zhang, Y-T, Wei, W, Sun, J, Xu, Q & Ni, B-J 2020, 'Long-Term Effects of Polyvinyl Chloride Microplastics on Anaerobic Granular Sludge for Recovering Methane from Wastewater', Environmental Science & Technology, vol. 54, no. 15, pp. 9662-9671.
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Polyvinyl chloride microplastics (PVC-MPs) are emerging contaminants affecting biological wastewater treatment processes. However, most of the previous studies mainly focused on their short-term impacts on floc sludge, with little work being conducted to explore their potential effects on more complex anaerobic granular sludge (AGS), which has been widely used for high-strength organic wastewater treatment. In this paper, the long-term effects of PVC-MPs on AGS were investigated via continuous feeding tests that are representative of real wastewater treatment processes. The results of a continuous 264 days test showed that the prolonged exposure of PVC-MPs at 15-150 MPs·L-1 significantly (p = 7.86 × 10-37, 3.44 × 10-43, and 5.29 × 10-46) inhibited the COD removal efficiency of AGS by 13.2%-35.5%, accompanied by a 11.0%-32.3% decreased production of methane and 40.3%-272.7% increased accumulation of short-chain fatty acids (SCFAs). In addition, the PVC-MPs exposure suppressed the secretion of extracellular polymeric substances (EPS), causing AGS and the inside microorganisms to lose the protection of EPS, thereby resulting in granule breakage and decreased cells viability. Aligning with the deteriorated performance, the long-term exposure of PVC-MPs reduced the total microbial populations and the relative abundances of key methanogens and acidogens. A toxicity mechanism assessment revealed that the negative impacts induced by PVC-MPs are mainly attributed to the toxic leachate and excess oxidative stress.
Zhao, S, Dou, P, Song, J, Nghiem, LD, Li, X-M & He, T 2020, 'Direct preparation of dialysate from tap water via osmotic dilution', Journal of Membrane Science, vol. 598, pp. 117659-117659.
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© 2019 Elsevier B.V. Preparation of dialysate for hemodialysis (or dialysis) requires dilution of the dialysis concentrate with purified water. Present practice contains two steps: first to purify water, and then water is transported to clinic to mix with the dialysate concentrate before treatment. As a new forward osmosis dialysis hybrid process, based on osmotic dilution, is evaluated for decentralized health care systems. A commercial cellulose triacetate (CTA) and a tailor-made thin film composite (TFC) polyamide FO membranes were examined. The rejection of salts in tap water by the FO membranes was investigated, and the real rejections of various ions as a function of permeate flux were well described by using a irreversible thermodynamic model. The hollow fiber TFC FO membrane showed higher water flux and lower reverse salt flux than the CTA membrane in diluting process. Both steric hindrance and electrostatic repulsion explained the rejection behavior of the membranes to the ions. Higher rejections of anions were obtained than cations, which was attributed to the anions selection characteristics of the membranes. No obvious foulings or scalings were observed in a relatively long time osmotic dilution process over 5 repeated cycles. The stable, high efficient osmotic dilution process in hemodialysis holds a strong promise in reducing the consumption of purified water or even eliminating the water purification step. This work provides a potentially new platform hemodialysis which can be portable and implementable away from major hospitals and major clinics.
Zheng, L, Price, WE, He, T & Nghiem, LD 2020, 'Simultaneous cooling and provision of make-up water by forward osmosis for post-combustion CO2 capture', Desalination, vol. 476, pp. 114215-114215.
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© 2019 This study evaluates the feasibility of forward osmosis (FO) for simultaneous post-combustion CO2 capture and make-up water provision using seawater and treated effluent as the feed. Three amine-based CO2 adsorbents (glycine, sodium glycinate, and monoethanolamine (MEA)) were used as draw solutes. A non-linear relationship between concentration of these adsorbents and conductivity (thus osmotic pressure) was observed. Glycine showed higher water flux and lower reverse salt flux and specific reverse salt flux than sodium glycinate and MEA in both membrane orientations, thus was selected for further investigations. A higher water flux but with the considerable flux decline were observed when active layer faced draw solution. In addition, temperature increase in draw solution could alter thermodynamic properties of glycine, resulting in an increase of reverse salt flux. Water flux increase was also observed due to diminishing concentrative internal concentration polarisation. Changes in water flux were insignificant when active layer faced feed solution even as temperature increased. Temperature increase was likely to aggravate the severity of dilutive internal concentration polarisation and offset the growth of osmotic pressure. Seawater could also be a potential source for simultaneous cooling and providing the make-up water, although the water flux was lower compared to treated effluent.
Zhou, X, Jin, W, Wang, Q, Guo, S, Tu, R, Han, S-F, Chen, C, Xie, G, Qu, F & Wang, Q 2020, 'Enhancement of productivity of Chlorella pyrenoidosa lipids for biodiesel using co-culture with ammonia-oxidizing bacteria in municipal wastewater', Renewable Energy, vol. 151, pp. 598-603.
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© 2019 Elsevier Ltd As one of the most promising renewable energy, microalgal biodiesel has been widely studied worldwide. However, the low-efficiency of conventional microalgae cultivation procedures restrict the development of microalgae biodiesel production. Microalgal-bacterial symbiosis could both enhance the growth of algal-bacterial culture and promote the removal and conversion of wastewater nutrients. In this study, three strains of high-efficient heterotrophic ammonia-oxidizing bacteria JN1, FN3, and FN5 were screened from municipal wastewater treatment system with over 80% degradation rates of 50 mg/L ammonia-nitrogen (NH3–N) in 24 h. Among them, FN5, belonging to Kluyvera sp., had the optimum effect on enhancing growth of oil-rich microalga Chlorella pyrenoidosa. In stationary phase, the biomass and lipid content of Chlorella pyrenoidosa was14.8% and 13.6% higher than the blank control tests without FN5. In contrast, JN1 and FN3 failed to enhance the growth of Chlorella pyrenoidosa. After the cultivation of Chlorella pyrenoidosa-FN5 consortia in municipal wastewater, the degradation rate of NH3–N was up to 91% while the content of microalgae biomass and lipid attained 0.35 g/L and 39.0%. The Saturated fatty acids (SFAs), Monounsaturated fatty acids (MUFAs), and Polyunsaturated fatty acids (PUFAs) were 43.9, 37.1 and 19.0%, respectively, which had the potential for biodiesel production after pretreatment.
Zhu, Y, Ouyang, L, Zhong, H, Liu, J, Wang, H, Shao, H, Huang, Z & Zhu, M 2020, 'Closing the Loop for Hydrogen Storage: Facile Regeneration of NaBH4 from its Hydrolytic Product', Angewandte Chemie International Edition, vol. 59, no. 22, pp. 8623-8629.
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AbstractSodium borohydride (NaBH4) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2, forming Na2B4O7⋅10 H2O and Na2CO3, both of which are ball‐milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2, bypasses the energy‐intensive dehydration procedure to remove water from Na2B4O7⋅10 H2O, and does not require high‐pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.
Zhu, Y, Ouyang, L, Zhong, H, Liu, J, Wang, H, Shao, H, Huang, Z & Zhu, M 2020, 'Closing the Loop for Hydrogen Storage: Facile Regeneration of NaBH4 from its Hydrolytic Product', Angewandte Chemie, vol. 132, no. 22, pp. 8701-8707.
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AbstractSodium borohydride (NaBH4) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2, forming Na2B4O7⋅10 H2O and Na2CO3, both of which are ball‐milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2, bypasses the energy‐intensive dehydration procedure to remove water from Na2B4O7⋅10 H2O, and does not require high‐pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.
Zhu, Y, Ouyang, L, Zhong, H, Liu, J, Wang, H, Shao, H, Huang, Z & Zhu, M 2020, 'Efficient Synthesis of Sodium Borohydride: Balancing Reducing Agents with Intrinsic Hydrogen Source in Hydrated Borax', ACS Sustainable Chemistry & Engineering, vol. 8, no. 35, pp. 13449-13458.
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© 2020 American Chemical Society. Sodium borohydride (NaBH4) has been identified as one of the most promising hydrogen storage materials; however, it is still challenging to produce NaBH4 with low cost and high efficiency, which are largely determined by the sources of boron and hydrogen and reducing agents used. Herein, we report an economical method to produce NaBH4 by ball milling hydrated borax (Na2B4O7·10H2O and/or Na2B4O7·5H2O) with different reducing agents such as MgH2, Mg, and NaH under ambient conditions. The direct use of natural hydrated borax avoids the dehydration process (at 600 °C) and consequently reduces cost and improves overall energy efficiency. A high yield of 93.1% can be achieved for a short ball mill duration (3.5 h) for Na2B4O7·5H2O-NaH-MgH2 system. In this system, H2 is generated in situ which subsequently reacts with Mg forming MgH2. Low cost Mg is therefore employed to replace the majority of MgH2, leading to an attractive yield of 78.6%. To further reduce the cost of raw materials and improve the utilization of hydrogen source in the hydrated borax, Na2B4O7·10H2O is used to partially substitute for Na2B4O7·5H2O, leading to a complete replacement of MgH2. Compared with literature results, the optimized recipe features low cost and high efficiency since it utilizes hydrogen from the hydrated water in natural borax and avoids high temperatures. Our finding is expected to facilitate applications of NaBH4 for hydrogen storage.
Zhuang, L-L, Li, M & Hao Ngo, H 2020, 'Non-suspended microalgae cultivation for wastewater refinery and biomass production', Bioresource Technology, vol. 308, pp. 123320-123320.
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