Afsari, M, Shon, HK & Tijing, LD 2021, 'Janus membranes for membrane distillation: Recent advances and challenges', Advances in Colloid and Interface Science, vol. 289, pp. 102362-102362.
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© 2021 Elsevier B.V. Membrane distillation (MD) is a promising hybrid thermal-membrane separation technology that can efficiently produce freshwater from seawater or contaminated wastewater. However, the relatively low flux and the presence of fouling or wetting agents in feed solution negate the applicability of MD for long term operation. In recent years, ‘two-faced’ membranes or Janus membranes have shown promising potential to decrease wetting and fouling problem of common MD system as well as enhance the flux performance. In this review, a comprehensive study was performed to investigate the various fabrication, modification, and novel design processes to prepare Janus membranes and discuss their performance in desalination and wastewater treatment utilizing MD. The promising potential, challenges and future prospects relating to the design and use of Janus membranes for MD are also tackled in this review.
Ahammad, NA, Badruddin, IA, Kamangar, S, Khaleed, HMT, Saleel, CA & Mahlia, TMI 2021, 'Heat Transfer and Entropy in a Vertical Porous Plate Subjected to Suction Velocity and MHD', Entropy, vol. 23, no. 8, pp. 1069-1069.
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This article presents an investigation of heat transfer in a porous medium adjacent to a vertical plate. The porous medium is subjected to a magnetohydrodynamic effect and suction velocity. The governing equations are nondepersonalized and converted into ordinary differential equations. The resulting equations are solved with the help of the finite difference method. The impact of various parameters, such as the Prandtl number, Grashof number, permeability parameter, radiation parameter, Eckert number, viscous dissipation parameter, and magnetic parameter, on fluid flow characteristics inside the porous medium is discussed. Entropy generation in the medium is analyzed with respect to various parameters, including the Brinkman number and Reynolds number. It is noted that the velocity profile decreases in magnitude with respect to the Prandtl number, but increases with the radiation parameter. The Eckert number has a marginal effect on the velocity profile. An increased radiation effect leads to a reduced thermal gradient at the hot surface.
Ahmed, MB, Rahman, MS, Alom, J, Hasan, MDS, Johir, MAH, Mondal, MIH, Lee, D-Y, Park, J, Zhou, JL & Yoon, M-H 2021, 'Microplastic particles in the aquatic environment: A systematic review', Science of The Total Environment, vol. 775, pp. 145793-145793.
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Microplastics (MPs) pollution has become one of the most severe environmental concerns today. MPs persist in the environment and cause adverse effects in organisms. This review aims to present a state-of-the-art overview of MPs in the aquatic environment. Personal care products, synthetic clothing, air-blasting facilities and drilling fluids from gas-oil industries, raw plastic powders from plastic manufacturing industries, waste plastic products and wastewater treatment plants act as the major sources of MPs. For MPs analysis, pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), Py-MS methods, Raman spectroscopy, and FT-IR spectroscopy are regarded as the most promising methods for MPs identification and quantification. Due to the large surface area to volume ratio, crystallinity, hydrophobicity and functional groups, MPs can interact with various contaminants such as heavy metals, antibiotics and persistent organic contaminants. Among different physical and biological treatment technologies, the MPs removal performance decreases as membrane bioreactor (> 99%) > activated sludge process (~98%) > rapid sand filtration (~97.1%) > dissolved air floatation (~95%) > electrocoagulation (> 90%) > constructed wetlands (88%). Chemical treatment methods such as coagulation, magnetic separations, Fenton, photo-Fenton and photocatalytic degradation also show moderate to high efficiency of MP removal. Hybrid treatment technologies show the highest removal efficacies of MPs. Finally, future research directions for MPs are elaborated.
Ahmed, SF, Hafez, MG, Chu, Y-M & Mofijur, M 2021, 'Turbulent energy motion of fiber suspensions in a rotating frame', Alexandria Engineering Journal, vol. 60, no. 3, pp. 3345-3352.
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Turbulent flows play a major role in many fields of science and industry. Noticeable attention is seen on turbulent flows of suspending fibers because of the sensitivity of the electrical, thermal, and mechanical properties of the connecting fiber composites to the spatial configuration and orientation of fibers. The involvement of fibers in the turbulent flow greatly affects the turbulent energy. It is more influenced when the turbulent flow occurs in a rotating system. The effect of fibers on the turbulent energy in the rotating frame must therefore be investigated. For turbulent energy with fiber suspension, a mathematical model can be built in a rotating system that is very important to enhance the quality of industrial goods. This paper, therefore, develops a mathematical model for turbulent energy motion in a rotating frame with a fiber suspension. The model was formulated using the averaging procedure. The momentum equation for incompressible and viscous fluid turbulent flow was considered to develop the model. The turbulent energy motion of the fiber suspensions was presented in the rotating frame in second-order correlation tensors,, and, where all the tensors are the function of time, distance, and space coordinates.
Ahmed, SF, Liu, G, Mofijur, M, Azad, AK, Hazrat, MA & Chu, Y-M 2021, 'Physical and hybrid modelling techniques for earth-air heat exchangers in reducing building energy consumption: Performance, applications, progress, and challenges', Solar Energy, vol. 216, pp. 274-294.
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Noteworthy advancements are seen in developing the earth-air heat exchanger (EAHE) models in the past several decades to reduce building energy consumption. However, it is still an ongoing challenge in selecting and implementing the most suitable and appropriate EAHE modelling technique in buildings based on the climates, performance, and limitations of the techniques. Therefore, this paper aims to review the published research related to the physical, and hybrid EAHE modelling techniques used in buildings, and highlight the prospects, benefits, progress, and challenges of these techniques. This is the first study that comprehensively evidences the prospects and technical challenges caused by unmeasured disturbances, assumptions, or the uncertainties generated in experimental and numerical works of all EAHE modelling techniques. Nevertheless, this study found that hybrid modelling is more effective than physical models for accurate prediction. On the contrary, the hybrid models suffer from high complexity if EAHE operating conditions and all key parameters are considered during the model development. Regarding the generalization capability, the physical models offer improved performance followed by the hybrid models. A minimum number of training data is needed for developing physical models, whereas medium training data is required for the hybrid models. The outcome of this study also provides valuable information regarding the physical and hybrid EAHE modelling techniques to the scientists, researchers, and so on in adopting the most appropriate EAHE modelling technique for their climates.
Ahmed, SF, Mofijur, M, Nuzhat, S, Chowdhury, AT, Rafa, N, Uddin, MA, Inayat, A, Mahlia, TMI, Ong, HC, Chia, WY & Show, PL 2021, 'Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater', Journal of Hazardous Materials, vol. 416, pp. 125912-125912.
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Emerging contaminants (ECs) in wastewater have recently attracted the attention of researchers as they pose significant risks to human health and wildlife. This paper presents the state-of-art technologies used to remove ECs from wastewater through a comprehensive review. It also highlights the challenges faced by existing EC removal technologies in wastewater treatment plants and provides future research directions. Many treatment technologies like biological, chemical, and physical approaches have been advanced for removing various ECs. However, currently, no individual technology can effectively remove ECs, whereas hybrid systems have often been found to be more efficient. A hybrid technique of ozonation accompanied by activated carbon was found significantly effective in removing some ECs, particularly pharmaceuticals and pesticides. Despite the lack of extensive research, nanotechnology may be a promising approach as nanomaterial incorporated technologies have shown potential in removing different contaminants from wastewater. Nevertheless, most existing technologies are highly energy and resource-intensive as well as costly to maintain and operate. Besides, most proposed advanced treatment technologies are yet to be evaluated for large-scale practicality. Complemented with techno-economic feasibility studies of the treatment techniques, comprehensive research and development are therefore necessary to achieve a full and effective removal of ECs by wastewater treatment plants.
Ahmed, SF, Mofijur, M, Tarannum, K, Chowdhury, AT, Rafa, N, Nuzhat, S, Kumar, PS, Vo, D-VN, Lichtfouse, E & Mahlia, TMI 2021, 'Biogas upgrading, economy and utilization: a review', Environmental Chemistry Letters, vol. 19, no. 6, pp. 4137-4164.
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Biogas production is rising in the context of fossil fuel decline and the future circular economy, yet raw biogas requires purification steps before use. Here, we review biogas upgrading using physical, chemical and biological methods such as water scrubbing, physical absorption, pressure swing adsorption, cryogenic separation, membrane separation, chemical scrubbing, chemoautotrophic methods, photosynthetic upgrading and desorption. We also discuss their techno-economic feasibility. We found that physical and chemical upgrading technologies are near-optimal, but still require high energy and resources. Biological methods are less explored despite their promising potential. High-pressure water scrubbing is more economic for small-sized plants, whereas potassium carbonate scrubbing provides the maximum net value for large-sized plants.
Ahmed, SF, Rafa, N, Mofijur, M, Badruddin, IA, Inayat, A, Ali, MS, Farrok, O & Yunus Khan, TM 2021, 'Biohydrogen Production From Biomass Sources: Metabolic Pathways and Economic Analysis', Frontiers in Energy Research, vol. 9.
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The commercialization of hydrogen as a fuel faces severe technological, economic, and environmental challenges. As a method to overcome these challenges, microalgal biohydrogen production has become the subject of growing research interest. Microalgal biohydrogen can be produced through different metabolic routes, the economic considerations of which are largely missing from recent reviews. Thus, this review briefly explains the techniques and economics associated with enhancing microalgae-based biohydrogen production. The cost of producing biohydrogen has been estimated to be between $10 GJ-1 and $20 GJ−1, which is not competitive with gasoline ($0.33 GJ−1). Even though direct biophotolysis has a sunlight conversion efficiency of over 80%, its productivity is sensitive to oxygen and sunlight availability. While the electrochemical processes produce the highest biohydrogen (>90%), fermentation and photobiological processes are more environmentally sustainable. Studies have revealed that the cost of producing biohydrogen is quite high, ranging between $2.13 kg−1 and 7.24 kg−1via direct biophotolysis, $1.42kg−1 through indirect biophotolysis, and between $7.54 kg−1 and 7.61 kg−1via fermentation. Therefore, low-cost hydrogen production technologies need to be developed to ensure long-term sustainability which requires the optimization of critical experimental parameters, microalgal metabolic engineering, and genetic modification.
Ahmed, SF, Saha, SC, Debnath, JC, Liu, G, Mofijur, M, Baniyounes, A, Chowdhury, SMEK & Vo, D-VN 2021, 'Data-driven modelling techniques for earth-air heat exchangers to reduce energy consumption in buildings: a review', Environmental Chemistry Letters, vol. 19, no. 6, pp. 4191-4210.
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Increasing population and urbanization call for smarter cities where the cycles of matter and energy are optimized, notably in buildings which are actually a source of pollution consuming a lot of energy. The efficiency of building energy has been improved by modelling earth-air heat exchangers, yet selecting the suitable models is challenging. Here we review data-driven earth-air heat exchanger models used for buildings. We discuss issues brought about by assumptions, unmeasured disruptions, and uncertainties in numerical and experimental works. We found that high accuracy can be reached if sufficient data is available. Models are appropriate for real-time activity due to their structure simplicity, yet they display a poor generalization capacity. Model development is limited by the constrained parameters and the complex boundary conditions of the heat exchangers.
Akther, N, Kawabata, Y, Lim, S, Yoshioka, T, Phuntsho, S, Matsuyama, H & Shon, HK 2021, 'Effect of graphene oxide quantum dots on the interfacial polymerization of a thin-film nanocomposite forward osmosis membrane: An experimental and molecular dynamics study', Journal of Membrane Science, vol. 630, pp. 119309-119309.
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We report an ultra-low loading of graphene oxide quantum dots (GQDs) into the polyamide (PA) layer of an outer-selective hollow fiber (OSHF) thin-film composite (TFC) membrane using the vacuum-assisted interfacial polymerization (VAIP) technique to improve the water permeability of OSHF TFC membranes without sacrificing membrane selectivity. Experimental results showed that GQD loading in the PA layer influenced membrane performance. The membrane with a GQD loading of 5 mg L (TFN5) demonstrated an optimal water flux of 30.9 L m h and a specific reverse solute flux (SRSF) of 0.12 g L . To investigate the effect of GQDs on the interfacial polymerization (IP) reaction and membrane performance, molecular dynamics (MD) simulation was employed at the water-hexane and water-PA interfaces. The simulation results showed that GQDs decreased the reaction rate during the IP process by reducing the diffusivities of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). Additionally, GQDs reduced water permeability by acting as barriers to water molecules when present at a high concentration near the PA layer surface. At a very high loading, GQDs aggregated at the water-hexane interface and reduced the membrane selectivity by forming non-selective voids at the interface between the PA layer and GQDs. Together with the experimental findings, the MD simulation results delivered a good insight into the GQDs' effect on the TFC membrane's surface and transport properties at both macroscopic and microscopic levels. −1 −2 −1 −1
Akther, N, Lin, Y, Wang, S, Phuntsho, S, Fu, Q, Ghaffour, N, Matsuyama, H & Shon, HK 2021, 'In situ ultrathin silica layer formation on polyamide thin-film composite membrane surface for enhanced forward osmosis performances', Journal of Membrane Science, vol. 620, pp. 118876-118876.
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© 2020 Elsevier B.V. Polyamide (PA) based thin-film composite (TFC) membranes experience a high degree of organic fouling due to their hydrophobic and rough membrane surfaces during forward osmosis (FO) process. In this study, an ultrathin silica layer was grown in situ on the PA surface to enhance the antifouling property of TFC membrane by silicification process. Surface characterization confirmed the development of a silica layer on the PA surface. The superhydrophilic surface of silica-deposited TFC membrane (contact angle of 20°) with 3 h silicification time (STFC-3h) displayed a 53% higher water flux than the pristine TFC membrane without significantly affecting the membrane selectivity. The silica-modified TFC FO membranes also exhibited excellent stability when subjected to long-term cross-flow shear stress rinsing using deionized (DI) water, including exposure to salty, acidic and basic solutions. Moreover, the fouling tests showed that STFC-3h membrane lost only 4.2%, 9.1% and 12.1% of its initial flux with bovine serum albumin (BSA), humic acid (HA) and sodium alginate (SA), respectively, which are considerably lower compared to the pristine TFC FO membrane where flux losses were 18.7%, 23.2% and 37.2%, respectively. The STFC-3h membrane also revealed higher flux recovery ratio (FRR) of 99.6%, 96.9% and 94.4% with BSA, HA and SA, respectively, after physical cleaning than the pristine membrane (91.4%, 88.7%, and 81.2%, respectively). Overall, the in situ formation of an ultrathin hydrophilic silica layer on the PA surface reported in this work shows that the TFC membrane's water flux and antifouling property could be improved without diminishing the membrane selectivity.
Akther, N, Sanahuja-Embuena, V, Górecki, R, Phuntsho, S, Helix-Nielsen, C & Shon, HK 2021, 'Employing the synergistic effect between aquaporin nanostructures and graphene oxide for enhanced separation performance of thin-film nanocomposite forward osmosis membranes', Desalination, vol. 498, pp. 114795-114795.
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Alam, MA, Muhammad, G, Khan, MN, Mofijur, M, Lv, Y, Xiong, W & Xu, J 2021, 'Choline chloride-based deep eutectic solvents as green extractants for the isolation of phenolic compounds from biomass', Journal of Cleaner Production, vol. 309, pp. 127445-127445.
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Bioresource valorization to obtain valuable phenolic compounds for medicinal, nutraceutical, food, and cosmetic applications are critical for a current and future sustainable and bio-based economy. Renewable, environmentally friendly, and non-toxic choline chloride-based deep eutectic solvents are the newest and utmost environmentally friendly alternatives to conventional organic solvents for the pretreatment and extraction of phenolic compounds. Recently, numerous studies have focused on phenolic compound extraction using choline chloride-based deep eutectic solvents as solvents or catalysts. Process variable optimization has been reported in terms of kinetic modeling and mechanisms involved in phenolic compounds extraction. This paper describes the cutting-edge methods used to extract phenolic compounds from different bio-based sources using choline chloride-based deep eutectic solvents. In addition, the factors affecting, kinetic models, and mechanisms involved in phenolic compound extraction using choline chloride-based deep eutectic solvents are thoroughly summarized. Moreover, future predictions, challenges, and anticipated growth in this field are addressed and can be used for biomass valorization.
Ali, SM, Im, S-J, Jang, A, Phuntsho, S & Shon, HK 2021, 'Forward osmosis system design and optimization using a commercial cellulose triacetate hollow fibre membrane module for energy efficient desalination', Desalination, vol. 510, pp. 115075-115075.
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This study is aimed at developing system mathematical design models to simulate and optimize a full scale forward osmosis (FO) for a hollow fibre membrane module for energy efficient desalination. Experimental data from a commercial outer selective CTA hollow fibre FO membrane module was used for validation. Less than 10% difference between the simulation and experimental results were observed which validated the reliability of the models. Simulation and design were performed for a 1000 m3/day FO plant using 0.6 M NaCl as draw solution (DS) (~seawater) and 0.02 M NaCl feed solution (FS) (~MBR effluent) to produce 0.25, 0.2 and 0.15 M NaCl diluted seawater to reduce the energy consumption of downstream pressure driven desalination process. A single element parallel module arrangement was found more suitable for this commercial hollow fibre membrane element. Finally, the numerical simulations revealed that to achieve 0.25, 0.20 and 0.15 M final DS concentrations, the optimum number of modules required were 370, 435 and 555 respectively considering membrane cost and energy consumption. The FO system using the commercial CTA hollow fibre module was found more energy efficient than a commercial TFC spiral wound membrane module.
Ali, SM, Kim, Y, Qamar, A, Naidu, G, Phuntsho, S, Ghaffour, N, Vrouwenvelder, JS & Shon, HK 2021, 'Dynamic feed spacer for fouling minimization in forward osmosis process', Desalination, vol. 515, pp. 115198-115198.
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In this study, a dynamic feed spacer is used to minimize the fouling problem of forward osmosis (FO) membrane process. The conceptual design of the spacer consists of a series of microturbines assembled in ladder type filament cells and termed as turbospacer. It exploits the kinetic energy of the flowing feed solution to rotate the turbines and creates high flow turbulence in the feed channel to prevent the accumulation of foulants and related performance decline. This proof of concept study employed a 3D printed prototype of the proposed spacer in a lab-scale FO experimental setup to compare their performances with a symmetric non-woven spacer of the same thickness under the same operating condition as a reference. Primary effluent from municipal wastewater treatment plant was used as feed solution for a short term (6 days) fouling experiment in this study. Outcomes of the FO fouling experiment revealed that the turbospacer resulted in (i) a factor 2 lower spacer channel pressure drop built-up, and (ii) a 15% reduction in flux decline compared to the reference symmetric spacer. Almost 2.5 times lower foulant resistance was obtained by using the turbospacer at the end of the fouling experiment. In addition, the analysis of the foulant layer growth over a particular position of the membrane surface captured by an optical coherence tomography (OCT) device at different stages of the experiment exhibited that the turbospacer produced a thinner foulant layer. In summary, the turbospacer demonstrated better fouling prevention and control in the FO process.
Alibeikloo, M, Khabbaz, H, Fatahi, B & Le, TM 2021, 'Reliability Assessment for Time-Dependent Behaviour of Soft Soils Considering Cross Correlation between Visco-Plastic Model Parameters', Reliability Engineering & System Safety, vol. 213, pp. 107680-107680.
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An elastic visco-plastic creep model was combined with the Monte-Carlo probabilistic method incorporating multivariate copula and nonlinear analysis to investigate the effects of uncertainties in the elastic visco-plastic model parameters on time-dependent settlement and the distribution of excess pore water pressure in soft soils under applied loads. The elastic-plastic model parameter (λ/V) and creep coefficient (ψ0/V) were considered as random variables with lognormal distribution while considering the cross correlation between these two random variables. When λ/V and ψ0/V were used as random variables, the coefficient of variation of time-dependent deformation gradually decreased approximately 25% over time until reaching an asymptote. By adopting over 50 years of monitoring data from the case study of Väsby test fill and results from the settlement ratio, the most appropriate cross correlation coefficient between selected random variables was introduced. The results revealed that increasing the cross correlation coefficient between λ/V and ψ0/V increased the standard deviation and the coefficient of variation of settlement up to 40%. Meanwhile, the corresponding statistical features for the predicted excess pore water pressure decreased as the cross correlation coefficient increased. This study also provides a practical insight into selecting the most suitable cross correlation coefficient between elastic visco-plastic model parameters, while adopting reliability-based design approach that captures the time-dependent deformation of embankments and structures built on soft soils.
Almuntashiri, A, Hosseinzadeh, A, Volpin, F, Ali, SM, Dorji, U, Shon, H & Phuntsho, S 2021, 'Removal of pharmaceuticals from nitrified urine', Chemosphere, vol. 280, pp. 130870-130870.
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In this study, granular activated carbon (GAC) was examined for the removal of five of the most commonly detected pharmaceuticals (naproxen, carbamazepine, acetaminophen, ibuprofen and metronidazole) from a nitrified urine to make the urine-derived fertiliser nutrient safe for food crops. Batch experiments were conducted to investigate the adsorption kinetics that described the removal of micropollutants (equal concentrations of 0.2 mM) from the synthetic nitrified urine at different GAC dosages (10-3000 mg/L). Artificial neural network modelling was also used to predict and simulate the removal of pharmaceuticals from nitrified urine. Langmuir and Freundlich isotherm models described the equilibrium data, with the Langmuir model providing slightly higher correlations. At the highest dose of 3000 mg/L GAC, all the pharmaceuticals showed a removal rates of over 90% after 1 h of adsorption time and 99% removal rates after 6 h of adsorption time. This study concludes that GAC is able to remove the targeted xenobiotics without affecting the concentration of N and P in the urine, suggesting that nitrified urine could be safely used as a nutrient product in future.
Alqaisi, R, Le, TM & Khabbaz, H 2021, 'Combined effects of eggshell powder and hydrated lime on the properties of expansive soils', Australian Geomechanics Journal, vol. 56, no. 1, pp. 107-118.
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This study involves the utilization of eggshell powder (ESP) as a supplementary additive to lime stabilization of expansive soil and evaluates its potential in enhancing the performance of expansive soil treated with lime. Eggshell is a waste material obtained from several sources. Some of the challenges associated with dumping eggshell are odour, insect growth, disposal costs and availability of disposal sites. In order to reduce these environmental issues, eggshells can be processed into ESP and play a role as a soil stabilizing agent. Calcium oxide is considered to be the main ingredient of the ESP. Therefore, an experimental program is carried out to test a mixture of kaolinite, bentonite and Sydney fine sand, which is simulated to be as an artificial expansive soil. The eggshell powder was used as an additive to 5% lime in four percentages of 5%, 10%, 15% and 20% by total dry weight of the soil mass. Results of linear shrinkage, proctor compaction, and unconfined compressive strength tests after various curing time are presented in detail and compared with untreated soil samples. The outcomes of these experimental investigations indicated that the combination of eggshell powder and hydrated lime led to a further decrease in linear shrinkage and the maximum dry density of expansive soil samples. It was found that the improved geotechnical characteristics were more pronounced for 5% ESP treated expansive soil. At this percentage, the compressive strength at failure and the corresponding strain increased slightly by 18% and 9%, respectively, compared to the untreated expansive soil after 28 days of curing. Moreover, in comparison with lime (5%) only stabilized expansive soil, the combined lime (5%) and ESP (5%), induced approximately 15% build-up in the compressive strength of samples. Based on the reasonable laboratory test results, this addition is recommended to improve the shrinkage properties and stabilize the expansive soils where the high perfo...
Al-Shetwi, AQ, Hannan, MA, Abdullah, MA, Rahman, MSA, Ker, PJ, Alkahtani, AA, Mahlia, TMI & Muttaqi, KM 2021, 'Utilization of Renewable Energy for Power Sector in Yemen: Current Status and Potential Capabilities', IEEE Access, vol. 9, pp. 79278-79292.
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A severe energy crisis has plagued Yemen for decades, and most of the population lack access to electricity. This has harmed the country’s economic, social, and industrial growth. Yemen generates electricity mainly from fossil fuels, despite having a high potential for renewable energy. Unfortunately, the situation has recently been compounded by the country’s continuing war, which has been ongoing since early 2015. It has impacted the country’s energy infrastructure negatively, resulting in power outages. Therefore, this paper aims to provide an updated perspective on Yemen’s current energy crisis and explain its key issues and potential solutions. Besides, it examines the potential, development, and current state of renewable energy sources, such as solar, wind, geothermal, and biomass. Based on the findings, Yemen is one of the world’s wealthiest countries in terms of sunlight and wind speed, and these two resources are abundant in all regions of the country. In addition, this paper sheds light on the solar energy revolution that has arisen since the war started due to the complete outage of the national electricity. Within a few years, solar energy in Yemen has increased its capacity by 50 times and has recently become the primary source of electricity for most Yemenis. Furthermore, the paper discusses the difficulties and challenges that face the implementation of renewable energy investment projects. Numerous recommendations for potential improvements in Yemen’s widespread use of renewable energy are also provided in this paper. All of the ideas presented in this paper are hoped to increase the efforts to grow renewable energy production in Yemen, thereby solving the issues of energy poverty and reducing environmental effects. The presented analysis can be used as a scientific reference for researchers and industrial companies looking for suitable solutions to advance Yemen’s renewable energy.
AlZainati, N, Saleem, H, Altaee, A, Zaidi, SJ, Mohsen, M, Hawari, A & Millar, GJ 2021, 'Pressure retarded osmosis: Advancement, challenges and potential', Journal of Water Process Engineering, vol. 40, pp. 101950-101950.
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An excessive amount of renewable energy could be possibly produced when solutions of dissimilar salinities are combined simultaneously in a semipermeable membrane. The aforestated energy harnessing for transformation into power could be achieved through the pressure retarded osmosis (PRO) process. The PRO system utilizes a semipermeable membrane for separating a low concentration solution from a pressurized-high concentrated solution. This work examines the recent developments and applications of the PRO process and potential energy that could be conceivably harvested from salinity gradient resources in a single-stage and multi-stage PRO processes. One of the existing challenges for this process is finding a commercial membrane that combines characteristics of the forward osmosis membrane (for reducing the phenomenon of concentration polarization) and the reverse osmosis membrane (to withstand high hydraulic pressure). For addressing this challenge, details about the commercial PRO membranes and the innovative laboratory fabricated PRO membranes are introduced. The potential of the PRO process is presented by elucidating salinity gradient resources, the energy of Pretreatment, the process design, PRO-desalination systems, and dual-stage PRO (DSPRO). It is anticipated that this paper can assist in widely understanding the PRO process and thus deliver important data for activating additional research and development.
Arandiyan, H, S. Mofarah, S, Sorrell, CC, Doustkhah, E, Sajjadi, B, Hao, D, Wang, Y, Sun, H, Ni, B-J, Rezaei, M, Shao, Z & Maschmeyer, T 2021, 'Defect engineering of oxide perovskites for catalysis and energy storage: synthesis of chemistry and materials science', Chemical Society Reviews, vol. 50, no. 18, pp. 10116-10211.
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The present work provides a critical review of the science and technological state-of-the-art of defect engineering applied to oxide perovskites in thermocatalytic, electrocatalytic, photocatalytic, and energy-storage applications.
Argyle, PA, Walworth, NG, Hinners, J, Collins, S, Levine, NM & Doblin, MA 2021, 'Multivariate trait analysis reveals diatom plasticity constrained to a reduced set of biological axes', ISME Communications, vol. 1, no. 1, p. 59.
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Abstract Trait-based approaches to phytoplankton ecology have gained traction in recent decades as phenotypic traits are incorporated into ecological and biogeochemical models. Here, we use high-throughput phenotyping to explore both intra- and interspecific constraints on trait combinations that are expressed in the cosmopolitan marine diatom genus Thalassiosira. We demonstrate that within Thalassiosira, phenotypic diversity cannot be predicted from genotypic diversity, and moreover, plasticity can create highly divergent phenotypes that are incongruent with taxonomic grouping. Significantly, multivariate phenotypes can be represented in reduced dimensional space using principal component analysis with 77.7% of the variance captured by two orthogonal axes, here termed a ‘trait-scape’. Furthermore, this trait-scape can be recovered with a reduced set of traits. Plastic responses to the new environments expanded phenotypic trait values and the trait-scape, however, the overall pattern of response to the new environments was similar between strains and many trait correlations remained constant. These findings demonstrate that trait-scapes can be used to reveal common constraints on multi-trait plasticity in phytoplankton with divergent underlying phenotypes. Understanding how to integrate trait correlational constraints and trade-offs into theoretical frameworks like biogeochemical models will be critical to predict how microbial responses to environmental change will impact elemental cycling now and into the future.
Awang, MSN, Mohd Zulkifli, NW, Abbas, MM, Amzar Zulkifli, S, Kalam, MA, Ahmad, MH, Mohd Yusoff, MNA, Mazlan, M & Daud, WMAW 2021, 'Effect of Addition of Palm Oil Biodiesel in Waste Plastic Oil on Diesel Engine Performance, Emission, and Lubricity', ACS Omega, vol. 6, no. 33, pp. 21655-21675.
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Badeti, U, Pathak, NK, Volpin, F, Dorji, U, Freguia, S, Shon, HK & Phuntsho, S 2021, 'Impact of source-separation of urine on effluent quality, energy consumption and greenhouse gas emissions of a decentralized wastewater treatment plant', Process Safety and Environmental Protection, vol. 150, pp. 298-304.
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The impact of urine diversion on the biological treatment processes at a decentralized wastewater treatment plant (WWTP) was investigated. BioWin software was used for the simulations, and the model was firstly validated with data from a real WWTP. The simulations showed that upto 82 % N, 30 % P, 6% chemical oxygen demand (COD) load to the WWTP can be reduced by complete urine diversion but effluent N reduction was notable up to 75 % urine diversion. Under the current WWTP operating conditions, the simulations suggest that 33 % of aeration energy can be saved by 90 % urine diversion. Direct N2O and CO2 emissions in the treatment processes can also be reduced by 98 % and 25 % respectively. Indirect green house gas emissions can also be reduced by 20 %. Overall, the reduction in the discharge of nutrients and in the operation of blowers was found to contribute to a 22 % reduction in the operating costs (on energy consumption and nutrient discharge).
Bagheri, S, Huang, Y, Walker, PD, Zhou, JL & Surawski, NC 2021, 'Strategies for improving the emission performance of hybrid electric vehicles', Science of The Total Environment, vol. 771, pp. 144901-144901.
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Low emission vehicle technologies need widespread adoption in the transport sector to overcome its significant decarbonisation challenges. Hybrid Electric Vehicles (HEVs) represent an intermediate technology between pure electric vehicles and internal combustion engines that have proven capability in reducing petroleum consumption. HEV customers often cite improved fuel economy as a major benefit from adopting this technology; however, outstanding questions remain regarding their respective emission levels. Through an extensive literature study, we show that several issues remain with HEV emissions performance which stem from frequent high-power cold starts, engine calibration issues and inefficient operating conditions for catalytic converters. HEVs have more NOx, HC, CO and particle number emissions compared to conventional vehicles by up to 21.0, 5.8, 9.0 and 23.3 times, respectively. Improved engine control algorithms, after-treatment design and thermal design of three-way catalysts emerge as research priorities for improving the emissions performance of HEVs.
Bai, X, Hou, S, Wang, X, Hao, D, Sun, B, Jia, T, Shi, R & Ni, B-J 2021, 'Mechanism of surface and interface engineering under diverse dimensional combinations: the construction of efficient nanostructured MXene-based photocatalysts', Catalysis Science & Technology, vol. 11, no. 15, pp. 5028-5049.
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Proposed scheme of the surface and interface engineering to improve the charge separation efficiency of MXene-based photocatalysts.
Bai, X, Jia, T, Wang, X, Hou, S, Hao, D & Bingjie-Ni 2021, 'High carrier separation efficiency for a defective g-C3N4 with polarization effect and defect engineering: mechanism, properties and prospects', Catalysis Science & Technology, vol. 11, no. 16, pp. 5432-5447.
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Different types of defects in g-C3N4 induce polarization effect to promote the separation of charge carriers and improve the photocatalytic efficiency.
Bao, T, Damtie, MM, Wei, W, Phong Vo, HN, Nguyen, KH, Hosseinzadeh, A, Cho, K, Yu, ZM, Jin, J, Wei, XL, Wu, K, Frost, RL & Ni, B-J 2021, 'Simultaneous adsorption and degradation of bisphenol A on magnetic illite clay composite: Eco-friendly preparation, characterizations, and catalytic mechanism', Journal of Cleaner Production, vol. 287, pp. 125068-125068.
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Excess bisphenol A (BPA) is a pollutant of concern in different water sources. In this work, magnetic illite clay-composite material (Fe3O4@illite) was synthesized via the coprecipitation method by loading Fe3O4 nanoparticles (nano-Fe3O4) onto the surfaces of illite clay. Results from different characterizations showed that nano-Fe3O4 was embedded into illite clay nanosheets and existed on the surfaces of illite clay, thereby reducing the degree of agglomeration and improving dispersibility. The catalytic BPA degradation of Fe3O4@illite and nano-Fe3O4 confirmed the superior performance of Fe3O4@illite compared with that of nano-Fe3O4. The optimum operating parameters for degradation were 0.3 mL of H2O2 at pH of 3 in the presence of Fe3O4@illite, which provided a maximum degradation capacity up to 816, 364, 113, and 68 mg/g for epoxy BPA concentration of resin wastewater (266 mg/L), synthetic wastewater (80 mg/L), Hefei City swan lake (25 mg/L), and Hefei University lake wastewater (14.94 mg/L), respectively, in 180 min reaction time. The degradation data conformed to the pseudo-first-order kinetic model. The degradation pathways and mineralization study revealed that the adsorption-Fenton-like reaction was the principal mechanism that demonstrated 100% degradation efficiency of Fe3O4@illite even after nine successive runs. The regeneration and reusability tendency analysis ensured that Fe3O4@illite can be easily separated by using magnets. Therefore, Fe3O4@illite composite with H2O2 Fenton-like technology was a promising method for BPA degradation.
Basha, JS, Jafary, T, Vasudevan, R, Bahadur, JK, Ajmi, MA, Neyadi, AA, Soudagar, MEM, Mujtaba, MA, Hussain, A, Ahmed, W, Shahapurkar, K, Rahman, SMA & Fattah, IMR 2021, 'Potential of Utilization of Renewable Energy Technologies in Gulf Countries', Sustainability, vol. 13, no. 18, pp. 10261-10261.
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This critical review report highlights the enormous potentiality and availability of renewable energy sources in the Gulf region. The earth suffers from extreme air pollution, climate changes, and extreme problems due to the enormous usage of underground carbon resources applications materialized in industrial, transport, and domestic sectors. The countries under Gulf Cooperation Council, i.e., Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates, mainly explore those underground carbon resources for crude oil extraction and natural gas production. As a nonrenewable resource, these are bound to be exhausted in the near future. Hence, this review discusses the importance and feasibility of renewable sources in the Gulf region to persuade the scientific community to launch and explore renewable sources to obtain the maximum benefit in electric power generation. In most parts of the Gulf region, solar and wind energy sources are abundantly available. However, attempts to harness those resources are very limited. Furthermore, in this review report, innovative areas of advanced research (such as bioenergy, biomass) were proposed for the Gulf region to extract those resources at a higher magnitude to generate surplus power generation. Overall, this report clearly depicts the current scenario, current power demand, currently installed capacities, and the future strategies of power production from renewable power sources (viz., solar, wind, tidal, biomass, and bioenergy) in each and every part of the Gulf region.
Beltrán, VH, Puill-Stephan, E, Howells, E, Flores-Moya, A, Doblin, M, Núñez-Lara, E, Escamilla, V, López, T & van Oppen, MJH 2021, 'Physiological diversity among sympatric, conspecific endosymbionts of coral (Cladocopium C1acro) from the Great Barrier Reef', Coral Reefs, vol. 40, no. 4, pp. 985-997.
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Bhol, P, Yadav, S, Altaee, A, Saxena, M, Misra, PK & Samal, AK 2021, 'Graphene-Based Membranes for Water and Wastewater Treatment: A Review', ACS Applied Nano Materials, vol. 4, no. 4, pp. 3274-3293.
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Birrer, SC, Wemheuer, F, Dafforn, KA, Gribben, PE, Steinberg, PD, Simpson, SL, Potts, J, Scanes, P, Doblin, MA & Johnston, EL 2021, 'Legacy Metal Contaminants and Excess Nutrients in Low Flow Estuarine Embayments Alter Composition and Function of Benthic Bacterial Communities', Frontiers in Microbiology, vol. 12, p. 661177.
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Coastal systems such as estuaries are threatened by multiple anthropogenic stressors worldwide. However, how these stressors and estuarine hydrology shape benthic bacterial communities and their functions remains poorly known. Here, we surveyed sediment bacterial communities in poorly flushed embayments and well flushed channels in Sydney Harbour, Australia, using 16S rRNA gene sequencing. Sediment samples were collected monthly during the Austral summer-autumn 2014 at increasing distance from a large storm drain in each channel and embayment. Bacterial communities differed significantly between sites that varied in proximity to storm drains, with a gradient of change apparent for sites within embayments. We explored this pattern for embayment sites with analysis of RNA-Seq gene expression patterns and found higher expression of multiple genes involved in bacterial stress response far from storm drains, suggesting that bacterial communities close to storm drains may be more tolerant of localised anthropogenic stressors. Several bacterial groups also differed close to and far from storm drains, suggesting their potential utility as bioindicators to monitor contaminants in estuarine sediments. Overall, our study provides useful insights into changes in the composition and functioning of benthic bacterial communities as a result of multiple anthropogenic stressors in differing hydrological conditions.
Cao, D-F, Zhu, H-H, Guo, C-C, Wu, J-H & Fatahi, B 2021, 'Investigating the hydro-mechanical properties of calcareous sand foundations using distributed fiber optic sensing', Engineering Geology, vol. 295, pp. 106440-106440.
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Cao, Y, Sheng, L, Cheng, H, Wang, C, Sun, Y & Fu, Q 2021, 'In situ synthesis of metal‐free N‐GQD@g‐C 3 N 4 photocatalyst for enhancing photocatalytic activity', Micro & Nano Letters, vol. 16, no. 1, pp. 77-82.
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Graphitic carbon nitride modified with N-doped graphene quantum dot (N-GQDs/g-C3N4) was prepared by an in situ method, in which the g-C3N4 was synthesized in the presence of N-GQD. Furthermore, the structure and photocatalytic degradation performance of in situ synthesised N-GQDs/g-C3N4 were investigated and compared with N-GQDs/g-C3N4 prepared by traditional mixing method. The removal efficiency was about 98.0% for the photocatalytic degradation of RhB after 70 min, which was larger comparing with other GQDs/g-C3N4 reported in previous works. The result was attributed to uniform distribution of N-GQDs on surface of g-C3N4, leading to more photogenerated electrons transfer. This work did not only report a new synthesis method of N-GQDs/g-C3N4, but also provided a new method to improve photodegradation performance of photocatalyst based on g-C3N4.
Celis-Plá, PSM, Rearte, TA, Neori, A, Masojídek, J, Bonomi-Barufi, J, Álvarez-Gómez, F, Ranglová, K, Carmo da Silva, J, Abdala, R, Gómez, C, Caporgno, M, Torzillo, G, Silva Benavides, AM, Ralph, PJ, Fávero Massocato, T, Atzmüller, R, Vega, J, Chávez, P & Figueroa, FL 2021, 'A new approach for cultivating the cyanobacterium Nostoc calcicola (MACC-612) to produce biomass and bioactive compounds using a thin-layer raceway pond', Algal Research, vol. 59, pp. 102421-102421.
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Chen, X, Hu, Z, Xie, H, Ngo, HH, Guo, W & Zhang, J 2021, 'Enhanced biocatalysis of phenanthrene in aqueous phase by novel CA-Ca-SBE-laccase biocatalyst: Performance and mechanism', Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 611, pp. 125884-125884.
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Chen, X, Huo, P, Liu, J, Li, F, Yang, L, Li, X, Wei, W, Liu, Y & Ni, B-J 2021, 'Model predicted N2O production from membrane-aerated biofilm reactor is greatly affected by biofilm property settings', Chemosphere, vol. 281, pp. 130861-130861.
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Even though modeling has been frequently used to understand the autotrophic deammonification-based membrane-aerated biofilm reactor (MABR), the relationships between system-specific biofilm property settings and model predicted N2O production have yet to be clarified. To this end, this study investigated the impacts of 4 key biofilm property settings (i.e., biofilm thickness/compactness, boundary layer thickness, diffusivity of soluble components in the biofilm structure, and biofilm discretization) on one-dimensional modeling of the MABR, with the focus on its N2O production. The results showed that biofilm thickness/compactness (200-1000 μm), diffusivity of soluble components in the biofilm structure (reduction factor of diffusivity: 0.2-0.9), and biofilm discretization (12-28 grid points) significantly influenced the simulated N2O production, while boundary layer thickness (0-300 μm) only played a marginal role. In the studied ranges of biofilm property settings, distinct upper and lower bounds of N2O production factor (i.e., the percentage ratio of N2O formed to NH4+ removed, 5.5% versus 2.3%) could be predicted. In addition to the microbial community structure, the N2O production pathway contribution differentiation was also subject to changes in biofilm property settings. Therefore, biofilm properties need to be quantified experimentally or set properly to model N2O production from the MABR correctly. As a good practice for one-dimensional modeling of N2O production from biofilm-based reactors, especially the MABR performing autotrophic deammonification, the essential information about those influential biofilm property settings identified in this study should be disclosed and clearly documented, thus ensuring both the reproducibility of modeling results and the reliable applications of N2O models.
Chen, Z, Wei, W & Ni, B-J 2021, 'Cost-effective catalysts for renewable hydrogen production via electrochemical water splitting: Recent advances', Current Opinion in Green and Sustainable Chemistry, vol. 27, pp. 100398-100398.
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Hydrogen, with zero-carbon footprint, high energy density, and earth abundance, is proved as a great energy carrier for a sustainable energy scheme, which is recognized as one key solution to mitigate climate change and reduce air pollution. To achieve this goal, reducing the cost of renewable hydrogen production via electrochemical water splitting is a requisite for supporting a reliable and affordable hydrogen economy. Thus, the development of cost-effective catalysts for water electrolysis is of great significance. In this review, the recent advances in low-cost electrocatalysts for water splitting are summarized, including transition metal–based catalysts and metal-free catalysts. The emphasis is put on the catalyst design strategies and the underlying structure–performance mechanisms. The challenges and perspectives in this booming field are also presented.
Chen, Z, Zheng, R, Deng, S, Wei, W, Wei, W, Ni, B-J & Chen, H 2021, 'Modular design of an efficient heterostructured FeS2/TiO2 oxygen evolution electrocatalyst via sulfidation of natural ilmenites', Journal of Materials Chemistry A, vol. 9, no. 44, pp. 25032-25041.
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Modular design of an efficient FeS2/TiO2 heterostructured OER catalyst from natural ilmenites via a sulfidation process.
Chen, Z, Zheng, R, Graś, M, Wei, W, Lota, G, Chen, H & Ni, B-J 2021, 'Tuning electronic property and surface reconstruction of amorphous iron borides via W-P co-doping for highly efficient oxygen evolution', Applied Catalysis B: Environmental, vol. 288, pp. 120037-120037.
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Designing cost-effective oxygen evolution reaction (OER) electrocatalysts is essential for sustainable water splitting. Recently, amorphous transition metal borides (TMBs) as OER pre-catalysts have acquired growing attention due to their favorable characteristics such as high conductivity, compositional and structural flexibility. Nevertheless, rational design of boride-based OER pre-catalysts remains an ongoing challenge. Herein, an efficient pre-catalyst derived from FeB with accelerated surface reconstruction and regulated intrinsic activity of evolved FeOOH is obtained by W and P co-doping. The obtained catalyst demonstrates an excellent OER activity with a low overpotential of 209 mV at a current density of 10 mA cm−2, and good stability in alkaline electrolyte, which surpasses most of boride-based OER catalysts. Specifically, the anion etching facilitates the surface reconstruction and accelerates the mass/charge transfer. Density functional theory calculations suggest W doping can enhance intrinsic catalytic activity via optimizing the adsorption free energy of reaction intermediates and improving the conductivity. Additionally, the hierarchical structure and amorphous feature also benefit the OER process. This study provides a fundamental insight into the correlation between surface structure and catalytic activity, and a powerful strategy to construct efficient OER pre-catalysts.
Chen, Z, Zheng, R, Zou, W, Wei, W, Li, J, Wei, W, Ni, B-J & Chen, H 2021, 'Integrating high-efficiency oxygen evolution catalysts featuring accelerated surface reconstruction from waste printed circuit boards via a boriding recycling strategy', Applied Catalysis B: Environmental, vol. 298, pp. 120583-120583.
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Converting electronic wastes into high-efficiency energy conversion catalysts is a win-win strategy in addressing the metal resources shortage and sustainable energy challenges. Herein, a facile boriding strategy is developed to directly convert the leachates of waste printed circuit boards into magnetic mixed metal borides (FeNiCuSnBs) for oxygen evolution reaction (OER) catalysts. Via the boriding process, a metal cation recovery rate of 99.78 %, 99.98 %, 99.96 %, and 99.49 % has been attained for Fe, Ni, Cu, and Sn, respectively. The obtained catalysts with a higher ratio of Ni and Fe show better OER performance. The optimal FNCSB-4 attains 10 mA cm−2 at a low overpotential of 199 mV, as well as good stability in alkaline solution. Remarkably, FNCSB-4 represents a record‐high activity among waste-derived OER electrocatalysts. In-depth study suggests that the superior OER performance is mainly owing to accelerated surface self-reconstruction by B/Sn co-etching under OER potential region, and the newly formed multimetal (oxy)hydroxides act as the active species for OER. Additionally, the efficient mass/charge transfer, the amorphous feature, and hierarchical structure also benefit OER. Apart from providing an insight into the correlation between surface self-reconstruction and OER activity of multimetal boride-based catalysts, this study also offers a general strategy for the high-efficiency recovery and advanced energy-driven applications of critical metals from other urban mines in a sustainable and environment-friendly approach.
Chen, Z, Zou, W, Zheng, R, Wei, W, Wei, W, Ni, B-J & Chen, H 2021, 'Synergistic recycling and conversion of spent Li-ion battery leachate into highly efficient oxygen evolution catalysts', Green Chemistry, vol. 23, no. 17, pp. 6538-6547.
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A one-pot synergetic recycling and regeneration strategy to develop highly efficient tri-metal OER electrocatalysts from spent LIB leachates is demonstrated.
Cheng, D, Liu, Y, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Zhang, S, Luo, G & Bui, XT 2021, 'Sustainable enzymatic technologies in waste animal fat and protein management', Journal of Environmental Management, vol. 284, pp. 112040-112040.
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Cheng, D, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Liu, Y, Liu, Y, Deng, L & Chen, Z 2021, 'Evaluation of a continuous flow microbial fuel cell for treating synthetic swine wastewater containing antibiotics', Science of The Total Environment, vol. 756, pp. 144133-144133.
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Microbial fuel cell (MFC) systems are promising technologies for wastewater treatment and renewable energy generation simultaneously. Performance of a double-chamber microbial fuel cell (MFC) to treat synthetic swine wastewater containing sulfonamide antibiotics (SMs) was evaluated in this study. The MFC was operated in continuous modes at different conditions. Results indicated that the current was successfully generated during the operation. The performance of MFC under the sequential anode-cathode operating mode is better than that under the single continuous running mode. Specifically, higher removal efficiency of chemical oxygen demand (>90%) was achieved under the sequential anode-cathode operating mode in comparison with that in the single continuous mode (>80%). Nutrients were also be removed in the MFC's cathode chamber with the maximum removal efficiency of 66.6 ± 1.4% for NH4+-N and 32.1 ± 2.8% for PO43--P. Meanwhile, SMs were partly removed in the sequential anode-cathode operating with the value in a range of 49.4%-59.4% for sulfamethoxazole, 16.8%-19.5% for sulfamethazine and 14.0%-16.3% for sulfadiazine, respectively. SMs' inhibition to remove other pollutants in both electrodes of MFC was observed after SMs exposure, suggesting that SMs exert toxic effects on the microorganisms. A positive correlation was found between the higher NH4+-N concentration used in this study and the removal efficiency of SMs in the cathode chamber. In short, although the continuous flow MFC is feasible for treating swine wastewater containing antibiotics, its removal efficiency of antibiotics requires to be further improved.
Cheng, D, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Nguyen, QA, Zhang, J & Liang, S 2021, 'Improving sulfonamide antibiotics removal from swine wastewater by supplying a new pomelo peel derived biochar in an anaerobic membrane bioreactor', Bioresource Technology, vol. 319, pp. 124160-124160.
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Sulfonamide antibiotics (SMs), as a class of antibiotics commonly used in swine industries, pose a serious threat to animal and human health. This study aims to evaluate the performance of an anaerobic membrane bioreactor (AnMBR) with and without supplying a new pomelo peel derived biochar to treat swine wastewater containing SMs. Results show that 0.5 g/L biochar addition could increase more than 30% of sulfadiazine (SDZ) and sulfamethazine (SMZ) removal in AnMBR. Approximately 95% of chemical oxygen demand (COD) was removed in the AnMBR at an influent organic loading rate (OLR) of 3.27 kg COD/(m3·d) while an average methane yield was 0.2 L/g CODremoved with slightly change at a small dose 0.5 g/L biochar addition. SMs inhibited the COD removal and methane production and increased membrane fouling. The addition of biochar could reduce the membrane fouling by reducing the concentration of SMP and EPS.
Cheng, H, Liu, Y, Huang, D, Cai, B & Wang, Q 2021, 'Rebooting kernel CCA method for nonlinear quality-relevant fault detection in process industries', Process Safety and Environmental Protection, vol. 149, pp. 619-630.
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Process monitoring is essential and important strategy for ensuring process safety and product quality. However, due to the nonlinear characteristics and multiple working conditions in process industries, the traditional process monitoring method cannot be effectively applied. Therefore, we propose a novel process monitoring framework, termed as mixture enhanced kernel canonical correlation analysis framework (M-NAKCCA). The innovations and advantages of M-NAKCCA are as follows: 1). The traditional CCA method is re-boosted as a new method, M-NAKCCA, to better nonlinear fault detection. Also, a matter-element model (MEm) is assimilated into M-NAKCCA to make the information more refined. 2). To overcome the curse of dimensionality that usually occurs in the high-dimensional dataset, M-NAKCCA uses the Nyström approximation technology to compress the kernel matrix. Moreover, the T2 control chart is reconstructed and the corresponding control upper limit is re-configured to improve the method sensitivity and to better the fault detection performance. 3). The proposed M-NAKCCA framework is firstly used to monitor a wastewater treatment plant (WWTP) and chemical plant with diverse process behaviors. The experimental results showed that the M-NAKCCA framework achieved the best performance for both of case studies.
Cheng, H, Wu, J, Huang, D, Liu, Y & Wang, Q 2021, 'Robust adaptive boosted canonical correlation analysis for quality-relevant process monitoring of wastewater treatment', ISA Transactions, vol. 117, pp. 210-220.
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Quality-relevant process monitoring has attracted much attention for its ability to assist in maintaining efficient plant operation. However, when the process suffers from non-stationary and over-complex (with noise, multiplicative faults, etc.) characteristics, the traditional methods usually cannot be effectively applied. To this end, a novel method, termed as Robust adaptive boosted canonical correlation analysis (Rab-CCA), is proposed to monitor the wastewater treatment processes. First, a robust decomposition method is proposed to mitigate the defects of standard CCA by decomposing the corrupted matrix into a low-matrix and a sparse matrix. Second, to further improve the performance of the standard process monitoring method, a novel criterion function and control charts are reconstructed accordingly. Moreover, an adaptive statistical control limit is proposed that can adjust the thresholds according to the state of a system and can effectively reduce the missed alarms and false alarms simultaneously. The superiority of Rab-CCA is verified by Benchmark Simulation Model 1 (BSM1) and a real full-scale wastewater treatment plant (WWTP).
Cheng, H, Yang, G, Li, D, Li, M, Cao, Y, Fu, Q & Sun, Y 2021, 'Ultralow Icing Adhesion of a Superhydrophobic Coating Based on the Synergistic Effect of Soft and Stiff Particles', Langmuir, vol. 37, no. 41, pp. 12016-12026.
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A novel superhydrophobic coating composed of soft polydimethylsiloxane microspheres and stiff SiO2 nanoparticles was developed and prepared. This superhydrophobic coating showed excellent superhydrophobicity with a large water contact angle of 171.3° and also exhibited good anti-icing performance and ultralow icing adhesion of 1.53 kPa. Furthermore, the superhydrophobic coating displayed good icing/deicing cycle stability, in which the icing adhesion was still less than 10.0 kPa after 25 cycles. This excellent comprehensive performance is attributed to stress-localization between ice and the surface, resulting from the synergistic effect of soft and stiff particles. This work thus opens a new avenue to simultaneously optimize the anti-icing and icephobic performance of a superhydrophobic surface for various applications.
Chowdhury, H, Chowdhury, T, Hossain, N, Chowdhury, P, Salam, B, Sait, SM & Mahlia, TMI 2021, 'Exergetic sustainability analysis of industrial furnace: a case study', Environmental Science and Pollution Research, vol. 28, no. 10, pp. 12881-12888.
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Industrial furnaces play a significant role in industrial energy consumption and production. Minimizing losses from these furnaces can contribute to industrial sustainability. Exergy being an optimization tool can reduce energy loss and emission from furnaces and contribute to environmental sustainability. Currently, no exergy-based sustainability analysis has been adopted in the literature. In this analysis, a reheater furnace that is fired by natural gas is analyzed in terms of energy and exergy utilization. To address the sustainability of the furnace, several exergy-based sustainability parameters have been used. The overall energy efficiency of the furnace is 93.40%, while exergy efficiency is only 27.37%. From sustainability analysis, it is found that 72.63% of the fuel is diminished from the furnace, and it contributes to a lower sustainability index of 1.38. Higher exergy losses from this furnace positively affect the environment, which is validated from the higher value of the environmental destruction coefficient, the environmental destruction index, and the lower value of the environmental benign index. The value of the environmental destruction coefficient is 3.65, and the value of the environmental benign index is 0.38. Recovering waste energy and optimizing auxiliary equipment will increase the value of sustainability parameters.
Chowdhury, MA, Shuvho, MBA, Shahid, MA, Haque, AKMM, Kashem, MA, Lam, SS, Ong, HC, Uddin, MA & Mofijur, M 2021, 'Prospect of biobased antiviral face mask to limit the coronavirus outbreak', Environmental Research, vol. 192, pp. 110294-110294.
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The rapid spread of COVID-19 has led to nationwide lockdowns in many countries. The COVID-19 pandemic has played serious havoc on economic activities throughout the world. Researchers are immensely curious about how to give the best protection to people before a vaccine becomes available. The coronavirus spreads principally through saliva droplets. Thus, it would be a great opportunity if the virus spread could be controlled at an early stage. The face mask can limit virus spread from both inside and outside the mask. This is the first study that has endeavoured to explore the design and fabrication of an antiviral face mask using licorice root extract, which has antimicrobial properties due to glycyrrhetinic acid (GA) and glycyrrhizin (GL). An electrospinning process was utilized to fabricate nanofibrous membrane and virus deactivation mechanisms discussed. The nanofiber mask material was characterized by SEM and airflow rate testing. SEM results indicated that the nanofibers from electrospinning are about 15-30 μm in diameter with random porosity and orientation which have the potential to capture and kill the virus. Theoretical estimation signifies that an 85 L/min rate of airflow through the face mask is possible which ensures good breathability over an extensive range of pressure drops and pore sizes. Finally, it can be concluded that licorice root membrane may be used to produce a biobased face mask to control COVID-19 spread.
Commault, AS, Kuzhiumparambil, U, Herdean, A, Fabris, M, Jaramillo-Madrid, AC, Abbriano, RM, Ralph, PJ & Pernice, M 2021, 'Methyl Jasmonate and Methyl-β-Cyclodextrin Individually Boost Triterpenoid Biosynthesis in Chlamydomonas Reinhardtii UVM4', Pharmaceuticals, vol. 14, no. 2, pp. 125-125.
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The commercialisation of valuable plant triterpenoids faces major challenges, including low abundance in natural hosts and costly downstream purification procedures. Endeavours to produce these compounds at industrial scale using microbial systems are gaining attention. Here, we report on a strategy to enrich the biomass of the biotechnologically-relevant Chlamydomonas reinhardtii strain UVM4 with valuable triterpenes, such as squalene and (S)-2,3-epoxysqualene. C. reinhardtii UVM4 was subjected to the elicitor compounds methyl jasmonate (MeJA) and methyl-β-cyclodextrine (MβCD) to increase triterpene yields. MeJA treatment triggered oxidative stress, arrested growth, and altered the photosynthetic activity of the cells, while increasing squalene, (S)-2,3-epoxysqualene, and cycloartenol contents. Applying MβCD to cultures of C. reinhardtii lead to the sequestration of the two main sterols (ergosterol and 7-dehydroporiferasterol) into the growth medium and the intracellular accumulation of the intermediate cycloartenol, without compromising cell growth. When MβCD was applied in combination with MeJA, it counteracted the negative effects of MeJA on cell growth and physiology, but no synergistic effect on triterpene yield was observed. Together, our findings provide strategies for the triterpene enrichment of microalgal biomass and medium.
Cong Nguyen, N, Thi Nguyen, H, Cong Duong, H, Chen, S-S, Quang Le, H, Cong Duong, C, Thuy Trang, L, Chen, C-K, Dan Nguyen, P, Thanh Bui, X, Guo, W & Hao Ngo, H 2021, 'A breakthrough dynamic-osmotic membrane bioreactor/nanofiltration hybrid system for real municipal wastewater treatment and reuse', Bioresource Technology, vol. 342, pp. 125930-125930.
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Dang, B-T, Bui, X-T, Itayama, T, Ngo, HH, Jahng, D, Lin, C, Chen, S-S, Lin, K-YA, Nguyen, T-T, Nguyen, DD & Saunders, T 2021, 'Microbial community response to ciprofloxacin toxicity in sponge membrane bioreactor', Science of The Total Environment, vol. 773, pp. 145041-145041.
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Dang, CC, Dang, LC, Khabbaz, H & Sheng, D 2021, 'Numerical study on deformation characteristics of fibre-reinforced load-transfer platform and columns-supported embankments', Canadian Geotechnical Journal, vol. 58, no. 3, pp. 328-350.
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In this investigation, a ground-modification technique utilising a fibre-reinforced load-transfer platform (FRLTP) and columns-supported (CS) embankment constructed on multi-layered soft soils is proposed and investigated. After validating the proposed model with published data in the literature, numerical analysis was firstly conducted on the two-dimensional finite element model of a CS embankment without or with FRLTP to examine the influence of the FRLTP inclusion into the CS embankment system. Secondly, an extensive parametric study was performed to further investigate the effects of the FRLTP essential parameters — including platform thickness, shear strength, and tensile strength properties — and deformation modulus on the embankment performance during the construction and post-construction stages. Additionally, the influence of the embankment design parameters, such as column spacing, column length, and diameter, was examined. The numerical results reveal that the FRLTP inclusion can be effective in enhancing the CS embankment behaviour. It is also found that when increasing the platform thickness, the shear strength properties of FRLTP play a significant role in improving the overall performance of a column embankment with FRLTP.
Dang, KB, Nguyen, TT, Ngo, HH, Burkhard, B, Müller, F, Dang, VB, Nguyen, H, Ngo, VL & Pham, TPN 2021, 'Integrated methods and scenarios for assessment of sand dunes ecosystem services', Journal of Environmental Management, vol. 289, pp. 112485-112485.
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Dang, LC, Khabbaz, H & Ni, B-J 2021, 'Improving engineering characteristics of expansive soils using industry waste as a sustainable application for reuse of bagasse ash', Transportation Geotechnics, vol. 31, pp. 100637-100637.
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Bagasse ash (BA) is an abundant industrial waste of the sugar-cane refining industry, and its improper disposal can result in a detrimental impact on the environment. In this investigation, BA is considered to assess the possible advantages of its pozzolanic component as a novel sustainable waste application for stabilisation of expansive soils. The engineering characteristics of expansive soils were investigated through an array of laboratory experiments on treated and untreated soil specimens mixed with various contents of additive and cured for different times. A comprehensive investigation of the microstructure evolution of soils after treatment was also undertaken using Fourier transform infrared and scanning electron microscopy techniques. The results revealed that addition of BA, lime, and in particular, combined BA-lime (BAL) remarkably improved the maximum strength (815%), the bearing capacity (9.2 times), the compressibility (83%), and the 100% swell properties of stabilised soils due to rich amorphous silica properties of BA waste that promoted higher pozzolanic reactivities of BAL-soil-mixtures and therefore, enhanced the engineering characteristics of treated soils. The findings showed that a proper combination of bagasse ash waste and lime, as a stabilising additive, can effectively enhance the engineering properties of expansive soil while addressing the environmental impact of BA waste disposal. The industrial waste (BA) can be reused as a cost-effective and green construction material for the benefit of sustainable development of civil infrastructure.
Dardor, D, Al Maas, M, Minier-Matar, J, Janson, A, Abdel-Wahab, A, Shon, HK & Adham, S 2021, 'Evaluation of pretreatment and membrane configuration for pressure-retarded osmosis application to produced water from the petroleum industry', Desalination, vol. 516, pp. 115219-115219.
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Devda, V, Chaudhary, K, Varjani, S, Pathak, B, Patel, AK, Singhania, RR, Taherzadeh, MJ, Ngo, HH, Wong, JWC, Guo, W & Chaturvedi, P 2021, 'Recovery of resources from industrial wastewater employing electrochemical technologies: status, advancements and perspectives', Bioengineered, vol. 12, no. 1, pp. 4697-4718.
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Ding, A, Song, R, Cui, H, Cao, H, Ngo, HH, Chang, H, Nan, J, Li, G & Ma, J 2021, 'Presence of powdered activated carbon/zeolite layer on the performances of gravity-driven membrane (GDM) system for drinking water treatment: Ammonia removal and flux stabilization', Science of The Total Environment, vol. 799, pp. 149415-149415.
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Ding, A, Zhang, R, Ngo, HH, He, X, Ma, J, Nan, J & Li, G 2021, 'Life cycle assessment of sewage sludge treatment and disposal based on nutrient and energy recovery: A review', Science of The Total Environment, vol. 769, pp. 144451-144451.
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With the acceleration of urbanization, the production of urban sludge is increasing rapidly. To minimize resource input and waste output, it is crucial to execute analyses of environmental impact and assessments of sustainability on different technical strategies involving sludge disposal based on Life Cycle Assessment (LCA), which is a great potential mean of environmental management adopted internationally in the 21st century. This review aims to compare the environmental sustainability of existing sludge management schemes with a purpose of nutrient recovery and energy saving, respectively, and also to include the substitution benefits of alternative sludge products. Simultaneously, LCA research regarding the emerging sludge management technologies and sludge recycling (cement, adsorbent, bricks) is analyzed. Additionally, the key aspects of the LCA process are worth noting in the context of the current limitations reviewed here. It is worth emphasizing that no technical remediation method can reduce all environmental damage simultaneously, and these schemes are typically more applicable to the assumed local conditions. Future LCA research should pay more attention to the toxic effects of different sludge treatment methods, evaluate the technical ways of adding pretreatment technology to the 'front end' of the sludge treatment process, and further explore how to markedly reduce environmental damage in order to maximize energy and nutrient recovery from the LCA perspective.
Ding, L, Zhou, J, Fu, Q, Bao, G, Liu, Y & Jin, D 2021, 'Triplet Fusion Upconversion with Oxygen Resistance in Aqueous Media', Analytical Chemistry, vol. 93, no. 10, pp. 4641-4646.
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Triplet fusion upconversion (also called triplet-triplet annihilation, TTA) arouses much attention due to its potential in the fields of biological imaging, optogenetics, and light harvesting. However, oxygen quenching remains a challenge ahead, restricting its applications in aqueous media. Previous efforts to realize aqueous TTA with oxygen resistance have been focused on core-shell structures and self-assembly, but tedious processes and complicated chemical modification are required. Here, we report a direct and efficient strategy to realize aqueous TTA by controlling the ionic equilibrium of the TTA dyad. We find that the ionized organic dyad in physiological buffers and electrolyte-based media shows a natural aerotolerance without any complicated structure engineering. In particular, the upconversion intensity of this aqueous TTA in Tris buffer under an air-saturated condition is more than twice that under the deaerated condition. We further demonstrate the TTA system for potential applications in pH and temperature sensing with reversible and sensitive performance. We anticipate this facile approach will inspire the development of practical aqueous TTA and broad applications in biological science.
Ding, W, Jin, W, Zhou, X, Yang, Q, Chen, C & Wang, Q 2021, 'Role of extracellular polymeric substances in anaerobic granular sludge: Assessing dewaterability during Fe(II)-peroxydisulfate conditioning and granulation processes', Journal of Cleaner Production, vol. 286, pp. 124968-124968.
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© 2020 Elsevier Ltd In this study, Fe(II) activated peroxydisulfate (PDS) conditioning and sludge granulation were conducted to investigate the dewaterability of anaerobic granular sludge (AGS). After Fe(II)-PDS conditioning, the dewaterability of three AGS from different sources was enhanced. The specific resistance to filtration (SRF) reduction rates were achieved (98.30% ± 0.19%, 99.51% ± 0.17% and 96.47% ± 1.25%, respectively) under the optimal Fe(II) and PDS additions; And the optimal reductions of capillary suction time (CST) were 93.49% ± 2.49%, 95.33% ± 0.02% and 88.04% ± 2.95%, respectively. The mechanism of improving AGS dewaterability by Fe(II)-PDS conditioning was proposed. The radical SO4⋅−/OH⋅ destroyed the structure of extracellular polymeric substances (EPS) layers and microbial cells, resulting in the bound water released from AGS. Thereafter, the generated Fe(III) facilitated the sludge re-flocculation and decreased the electrostatic repulsion. During a 132-day granulation, the CST value showed a positive correlation with protein (S-EPS), polysaccharide and zeta potential, and a negative correlation with protein (LB-EPS), protein (TB-EPS), particle size and VSS. Collectively, the protein was the primary component in AGS and showed a strong correlation with dewaterability. The variations of protein in TB-EPS during the conditioning and the granulation were consistent with the changes of sludge dewaterability.
Doan, S & Fatahi, B 2021, 'Green’s function analytical solution for free strain consolidation of soft soil improved by stone columns subjected to time-dependent loading', Computers and Geotechnics, vol. 136, pp. 103941-103941.
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This paper proposes an analytical solution in terms of Green's function formulations for axisymmetric consolidation of a stone column improved soft soil deposit subjected to time-dependent loading under free strain condition. The mathematical derivations incorporate the pore water flows in radial and vertical directions in stone column and soft soil synchronously. The capabilities of the proposed analytical solution are evaluated via worked examples investigating the influences of three common time-dependent external surcharges (namely step, ramp and sinusoidal loadings) on consolidation response of the composite ground. The examples show that a faster increase of load from an initial surcharge to an expected loading might generate more significant excess pore water pressure to be dissipated during the early stages of consolidation, but the dissipation rate in soft soil would speed up significantly afterwards. The column and soil settlements along with the differential settlement between them also proceed faster corresponding to the acceleration of loading – unloading processes. Finally, the proposed analytical solution is employed to evaluate the excess pore water pressure dissipation rate at an investigation point in soft clay of a case history foundation. The calculation results exhibit a reasonable agreement with field measurement data when various constant values of stress concentration ratio are substituted into the solution to reflect the increase of stress concentration ratio with consolidation time in real practice.
Dorji, U, Tenzin, U, Dorji, P, Pathak, N, Johir, MAH, Volpin, F, Dorji, C, Chernicharo, CAL, Tijing, L, Shon, H & Phuntsho, S 2021, 'Exploring shredded waste PET bottles as a biofilter media for improved on-site sanitation', Process Safety and Environmental Protection, vol. 148, pp. 370-381.
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This study explores an improved alternative on-site treatment for unsewered urban Bhutan. The system combines up-flow anaerobic sludge blanket for blackwater treatment and anaerobic biofilter for a mixture of up-flow anaerobic sludge blanket effluent and greywater. Shredded waste plastic bottles are used as novel biofilter media that provides a large surface area for attached growth while addressing waste plastic problems. A bench-scale up-flow anaerobic sludge blanket (operated at hydraulic retention time or HRT of 1–10 days) and anaerobic biofilter (HRT of 0.25–3 days) study were conducted for 188 days. At 2-d HRT, up-flow anaerobic sludge blanket removed 70–80 % of chemical oxygen demand (COD) while anaerobic biofilter achieved 90–98 % COD removal at eight-hour HRT. Combined up-flow anaerobic sludge blanket and anaerobic biofilter achieved final effluent with COD less than 50 mg/L and turbidity of less than 3 NTU that meets the discharge standard of Bhutan. The study shows that shredded waste plastic bottles can be an effective biofilter support medium for low-cost on-site treatment while helping address waste plastic problems.
Du, M, Liu, X, Wang, D, Yang, Q, Duan, A, Chen, H, Liu, Y, Wang, Q & Ni, B-J 2021, 'Understanding the fate and impact of capsaicin in anaerobic co-digestion of food waste and waste activated sludge', Water Research, vol. 188, pp. 116539-116539.
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Anaerobic co-digestion is an attractive option to treat food waste and waste activated sludge, which is increasingly applied in real-world situations. As an active component in Capsicum species being substantially present in food waste in many areas, capsaicin has been recently demonstrated to inhibit the anaerobic co-digestion. However, the interaction between capsaicin and anaerobic co-digestion are still poorly understood. This work therefore aims to deeply understand the fate and impact of capsaicin in the anaerobic co-digestion. Experiment results showed that capsaicin was completely degraded in anaerobic co-digestion by hydroxylation, O-demethylation, dehydrogenation and doubly oxidization, respectively. Although methane was proven to be produced from capsaicin degradation, the increase in capsaicin concentration resulted in decrease in methane yield from the anaerobic co-digestion. With an increase of capsaicin from 2 ± 0.7 to 68 ± 4 mg/g volatile solids (VS), the maximal methane yield decreased from 274.6 ± 9.7 to 188.9 ± 8.4 mL/g VS. The mechanic investigations demonstrated that the presence of capsaicin induced apoptosis, probably by either altering key kinases or decreasing the intracellular NAD+/NADH ratio, which led to significant inhibitions to hydrolysis, acidogenesis, and methanogenesis, especially acetotrophic methanogenesis. Illumina Miseq sequencing analysis exhibited that capsaicin promoted the populations of complex organic degradation microbes such as Escherichia-Shigella and Fonticella but decreased the numbers of anaerobes relevant to hydrolysis, acidogenesis, and methanogenesis such as Bacteroide and Methanobacterium.
Duong, HC, Tran, LTT, Vu, MT, Nguyen, D, Tran, NTV & Nghiem, LD 2021, 'A new perspective on small-scale treatment systems for arsenic affected groundwater', Environmental Technology & Innovation, vol. 23, pp. 101780-101780.
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This work provides a new perspective on small-scale treatment systems to remove arsenic from groundwater for potable applications in low-income communities. Data corroborated from the literature highlight a significant challenge to providing potable water in a financially sustainable manner in arsenic affected areas. Analysis of the literature also reveals notable deficiency in the current practice, especially the overfocus on household-scale treatment systems for arsenic affected groundwater without adequate maintenance, monitoring, and a systematic cost–benefit analysis. Accurate and reliable analysis of arsenic in water samples at relevant health guideline values is costly and technologically demanding for low-income communities. Significant discrepancy in the performance of household-scale treatment systems can be attributed to the lack of maintenance and systematic monitoring. Moreover, data on the maintenance and compliance monitoring cost of small-scale arsenic treatment systems are very limited in the literature, and the available data show an exponential increase in maintenance cost per treatment capacity unit as the treatment size decreases. On the other hand, significant opportunities exist to increase performance reliability and reduce water treatment cost by taking advantage of the current digital transformation of the water sector. The analysis in this work suggests the need to reframe current practice towards commune-scale treatment systems as an interim step before centralised water supply is available.
Ejaz, A, Babar, H, Ali, HM, Jamil, F, Janjua, MM, Fattah, IMR, Said, Z & Li, C 2021, 'Concentrated photovoltaics as light harvesters: Outlook, recent progress, and challenges', Sustainable Energy Technologies and Assessments, vol. 46, pp. 101199-101199.
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Concentrated photovoltaics (CPV) is a dawn technology in the field of photovoltaic that helps in escalating the effective use of solar energy. Nowadays, applications of photovoltaic solar cells are catching attention due to the better utilization of solar energy. A huge amount of solar energy is received by the earth from the sun, but a barrier to the large-scale use of photovoltaic solar cells is their higher initial cost and lower conversion compared to other non-renewable energy systems. Concentrated Photovoltaics (CPV) is one of the vital tools that focus solar radiation on the small area of solar cells using optical devices to maximize solar to thermal conversion. Low cost, high efficiency, and climate-friendly are the main advantages of concentrated photovoltaics. The review study presents the outlook of work conducted worldwide on the different types of concentrated photovoltaics. In addition, the effect of various performance affecting parameters, challenges, and recent progress is also part of the study. Most of the CPV have efficiency up to 15% while some have an efficiency range of 25–28% which is still very low. It was found that the CPV gave maximum efficiency of up to 38.5% at optimal solar radiation. The focus of sunlight on a small area of solar cell increases the temperature of concentrated photovoltaic allegedly pernicious for electrical efficiency and the life of CPV. Factors like direct normal irradiance, high cell temperature, soiling, optical design, reliability, and durability are considered as challenges and a concise summary of various studies on these challenges is presented. In this regard, various cooling techniques have been investigated by different researchers for thermal management of CPV systems which are discussed in detail. As CPV technology is still in the development phase, various new optical designs emphasizing novel designs and materials are also summarized in the current study. Finally, some recommendations are o...
Ejeian, M, Grant, A, Shon, HK & Razmjou, A 2021, 'Is lithium brine water?', Desalination, vol. 518, pp. 115169-115169.
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With the development of light and rechargeable batteries for electric vehicles, global demand for lithium has increased considerably in recent years. This has drawn more attention to how lithium is produced, especially on primary extraction operations such as those at the Salar de Atacama in Northern Chile. There are concerns that brine extraction at the Atacama could irreversibly damage the basin's complex hydrological system. However, differing opinions over the definition of water have frustrated basic action measures for minimizing impacts of operations like these. Some lithium industry stakeholders have historically described brine as a mineral, while others emphasize that brine is also a type of water in a complex network of different water resources. In this communication, we show that brines are undeniably a type of water. We support this position by investigating brine's water molecular structure using molecular dynamics simulations and comparing Gibbs formation energy of the brine using thermodynamic principles. Molecular dynamics show that the structure of water molecules in brine is similar to the structure of molecules in pure water at a pressure of 1.2 atm. The analysis of Gibbs formation energy shows that more than 99% of the brine's formation energy is directly from water, not dissolved minerals.
Ekanayake, D, Loganathan, P, Johir, MAH, Kandasamy, J & Vigneswaran, S 2021, 'Enhanced Removal of Nutrients, Heavy Metals, and PAH from Synthetic Stormwater by Incorporating Different Adsorbents into a Filter Media', Water, Air, & Soil Pollution, vol. 232, no. 3.
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Stormwater harvesting and reuse is an attractive option to lower the demand placed on other sources of water supply. However, it contains a wide range of pollutants that need to be removed before it can be reused or even discharged to the waterways and receiving waters. An experimental protocol to estimate the efficiency of a soil-based-filter medium for the treatment of stormwater pollutants from 1 to 3 years rainfall experienced in the field was developed using a laboratory column-set-up over short-term duration. The filter removed substantial amounts of PO -P and NH -N for up to 8 h at a flow velocity of 100 mm/h which is a 1-year time-equivalent of rainfall at a locality in Sydney, Australia. An addition of 10% zeolite to the soil-based filter extended the column saturation period to 24 h. The breakthrough data for PO -P and NH -N were satisfactorily described by the Thomas model. The majority of the nine heavy metals tested were removed by more than 50% for up to 4 h in the soil-based filter. This level of removal increased to 16 h when 10% zeolite was added to the filter. The column with the soil-based filter + 10% zeolite had higher affinity for Pb, Cu, Zn, and As than Ni, with Pb having the highest percentage removal. Soil-based filter + 10% zeolite removed considerable amounts of 3 polycyclic aromatic hydrocarbons (PAHs) (30–50%), while soil-based filter + 10% zeolite + 0.3% granular activated carbon removed 65 to > 99% of the PAHs at 24-h operation. 4 4 4 4
Ekanayake, UGM, Barclay, M, Seo, DH, Park, MJ, MacLeod, J, O'Mullane, AP, Motta, N, Shon, HK & Ostrikov, KK 2021, 'Utilization of plasma in water desalination and purification', Desalination, vol. 500, pp. 114903-114903.
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© 2020 Elsevier B.V. Supplying fresh drinking water to the world population is a persistent global challenge. Therefore, effective and efficient desalination processes are becoming increasingly important. Oceans account for most of the water on Earth and the presence of salts and other contaminants in seawater prevents them from being used as a source of drinking water. Owing to this challenge, non-thermal plasma can be utilized in order to enhance the existing desalination processes via membrane or material modification while it can also be used as a direct tool for seawater desalination leading to significant process improvements. A direct non-thermal plasma-based desalination process is a new emerging area of research and recent efforts have shown its promise with many unexplored mechanisms, providing benefits that conventional desalination processes cannot offer. Here we critically review the use of plasma technologies in water desalination including membrane modification by plasma for pressure, thermal, photothermal processes and direct plasma-based desalination process. We also address the use of plasmas in water purification. Finally, the existing challenges and future prospects are outlined.
Fadillah, G, Fatimah, I, Sahroni, I, Musawwa, MM, Mahlia, TMI & Muraza, O 2021, 'Recent Progress in Low-Cost Catalysts for Pyrolysis of Plastic Waste to Fuels', Catalysts, vol. 11, no. 7, pp. 837-837.
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The catalytic and thermal decomposition of plastic waste to fuels over low-cost catalysts like zeolite, clay, and bimetallic material is highlighted. In this paper, several relevant studies are examined, specifically the effects of each type of catalyst used on the characteristics and product distribution of the produced products. The type of catalyst plays an important role in the decomposition of plastic waste and the characteristics of the oil yields and quality. In addition, the quality and yield of the oil products depend on several factors such as (i) the operating temperature, (ii) the ratio of plastic waste and catalyst, and (iii) the type of reactor. The development of low-cost catalysts is revisited for designing better and effective materials for plastic solid waste (PSW) conversion to oil/bio-oil products.
Fang, C, Liu, W, Zhang, P, Rajabzadeh, S, Kato, N, Sasaki, Y, Shon, HK & Matsuyama, H 2021, 'Hollow fiber membranes with hierarchical spherulite surface structure developed by thermally induced phase separation using triple-orifice spinneret for membrane distillation', Journal of Membrane Science, vol. 618, pp. 118586-118586.
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© 2020 Elsevier B.V. Polyvinylidene fluoride (PVDF) hollow fiber membranes were developed by the thermally induced phase separation (TIPS) process using a triple-orifice spinneret with solvent co-extrusion at the outermost channel for applications in membrane distillation (MD). The polymer surface concentration during membrane preparation was controlled by exploiting the interfacial interactions of the diluent and polymer at the extruded solvent surface. The membrane surface was controlled from a dense to a porous structure with a large pore size and a high porosity, which considerably enhanced the membrane water vapor permeability to 13.5 L m−2 h−1. Furthermore, the solvent co-extrusion was responsible for the formation of surface spherulites with different shapes, such as contacted spherulites, isolated spherulites, and isolated spherulites with humps. The spherulites with humps constructed a novel hierarchical structure, which created a superhydrophobic surface that conferred upon the PVDF membrane a remarkable wetting resistance in the MD process toward low-surface-tension saline water. More significantly, all the unique structures were achieved using the one-step membrane fabrication process of solvent co-extrusion without additional processes and materials. Thus, this work provides a new, simple, and useful alternative for the preparation of hollow fiber membranes with high performances for MD desalination.
Fang, C, Liu, W, Zhang, P, Yao, M, Rajabzadeh, S, Kato, N, Kyong Shon, H & Matsuyama, H 2021, 'Controlling the inner surface pore and spherulite structures of PVDF hollow fiber membranes in thermally induced phase separation using triple-orifice spinneret for membrane distillation', Separation and Purification Technology, vol. 258, pp. 117988-117988.
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© 2020 Elsevier B.V. In this study, we controlled the inner surface structures of polyvinylidene fluoride (PVDF) hollow fiber membranes via a thermally induced phase separation process using a triple-orifice spinneret for direct-contact membrane distillation (DCMD). The coextrusion of propylene carbonate (PC) through the outermost channel of the spinneret led to porous outer surfaces with similar pore sizes and spherulitic structures for all the PVDF hollow fiber membranes. In the innermost channel, the extrusion of solvents having different compatibilities with PVDF and the diluent (PC) as the bore liquids controlled the inner surface pore sizes and spherulite structures, and the effects of these inner surface structures on the DCMD performance were investigated in detail. Increasing the compatibility of the bore liquids toward the diluent led to an increase in the inner surface pore size because of the formation of loose, isolated spherulites, which remarkably enhanced the water vapor permeability from 4 to 8.3 L m−2 h−1, while reducing the membrane hydrophobicity, liquid entry pressure, and salt rejection. When increasing the bore liquid compatibility with the polymer, the surface pore size decreased because of the tight spherulite contact, enhancing membrane salt rejection and wetting resistance. Given the significance of bore liquid compatibility with the diluent and the polymer in controlling the inner surface structures, a useful guideline is presented for selecting the appropriate bore liquids to prepare hollow fiber membranes with the desired inner surface structures for high MD performance.
Fang, F, Xu, R-Z, Huang, Y-Q, Luo, J-Y, Xie, W-M, Ni, B-J & Cao, J-S 2021, 'Exploring the feasibility of nitrous oxide reduction and polyhydroxyalkanoates production simultaneously by mixed microbial cultures', Bioresource Technology, vol. 342, pp. 126012-126012.
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Nitrous oxide (N2O), as a powerful greenhouse gas, has drawn increasing attention in recent years and different strategies for N2O reduction were explored. In this study, a novel strategy for valuable polyhydroxyalkanoates (PHA) production coupling with N2O reduction by mixed microbial cultures (MMC) using different substrates was evaluated. Results revealed that N2O was an effective electron acceptor for PHA production. The highest PHA yield (0.35 Cmmol PHA/Cmmol S) and PHA synthesis rate (227.47 mg PHA/L/h) were obtained with acetic acid as substrate. Low temperature (15℃) and pH of 8.0 were beneficial for PHA accumulation. Results of the thermogravimetric analysis showed that PHA produced with N2O as electron acceptor has better thermal stability (melting temperature of 99.4℃ and loss 5% weight temperature of 211.4℃). Our work opens up new avenues for simultaneously N2O reduction and valuable bioplastic production, which is conducive to resource recovery and climate protection.
Farooq, MA, Nimbalkar, S & Fatahi, B 2021, 'Three-dimensional finite element analyses of tyre derived aggregates in ballasted and ballastless tracks', Computers and Geotechnics, vol. 136, pp. 104220-104220.
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Scrap tyres are a significant source of pollution and pose a grave threat to the environment and human health. The present study aims to examine the application of Tyre Derived Aggregate (TDA) in a concrete slab track and ballasted track and compare its performance in both track forms. In this study, long-term performance of slab track and ballasted track subjected to train induced loading is demonstrated based on the three-dimensional finite element modelling. The most suitable constitutive hyperelastic model for TDA has been identified. Subsequently, the most suitable position for the location of TDA is determined for both track types. A comparative analysis between slab track and ballasted track, with and without TDA, is presented in terms of stress transfer, vibration reduction and displacement (elastic and plastic). It is shown that TDA helps in reducing up to 50% vibration levels of both track types. The influence of train speed and axle load on the vertical and horizontal displacement and stress response of both track forms is shown for a large number of load cycles. Overall, it is observed that the long-term performance of TDA is better in slab track compared to ballasted track.
Feng, S, Hao Ngo, H, Guo, W, Woong Chang, S, Duc Nguyen, D, Cheng, D, Varjani, S, Lei, Z & Liu, Y 2021, 'Roles and applications of enzymes for resistant pollutants removal in wastewater treatment', Bioresource Technology, vol. 335, pp. 125278-125278.
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Resistant pollutants like oil, grease, pharmaceuticals, pesticides, and plastics in wastewater are difficult to be degraded by traditional activated sludge methods. These pollutants are prevalent, posing a great threat to aquatic environments and organisms since they are toxic, resistant to natural biodegradation, and create other serious problems. As a high-efficiency biocatalyst, enzymes are proposed for the treatment of these resistant pollutants. This review focused on the roles and applications of enzymes in wastewater treatment. It discusses the influence of enzyme types and their sources, enzymatic processes in resistant pollutants remediation, identification and ecotoxicity assay of enzymatic transformation products, and typically employed enzymatic wastewater treatment systems. Perspectives on the major challenges and feasible future research directions of enzyme-based wastewater treatment are also proposed.
Fonseka, C, Ryu, S, Choo, Y, Mullett, M, Thiruvenkatachari, R, Naidu, G & Vigneswaran, S 2021, 'Selective Recovery of Rare Earth Elements from Mine Ore by Cr-MIL Metal–Organic Frameworks', ACS Sustainable Chemistry & Engineering, vol. 9, no. 50, pp. 16896-16904.
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Rare earth elements (REEs) have become a strategic resource extensively used in renewable energy technologies and modern electronic devices. Depletion of natural REE-bearing mineral deposits has made selective recovery of REEs from alternative sources crucial in meeting the rising global demand. A chromium-based metal–organic framework was synthesized and modified with N-(phosphonomethyl)iminodiacetic acid (PMIDA) in this study to selectively recover REEs (europium, Eu) from chemically complex zinc ore leachate. The adsorbent was characterized and comprehensively examined for Eu uptake as a function of adsorbate concentration, contact time, and pH of the solution. Cr-MIL-PMIDA showed a maximum adsorption capacity of 69.14 mg/g at pH 5.5 while adsorption kinetics best fitted the pseudo-second-order model. Furthermore, Cr-MIL-PMIDA showed exceptional selectivity (88%) toward Eu over competing transitional metal ions (Na, Mg, Al, Ca, Mn, Fe, Ni, Cu, Co, and Zn) found in the dissolved mine ore. High selectivity toward REEs was attributed to the formation of coordinative complexes with grafted carboxylate, phosphonic, and residual amine functional groups. Cr-MIL-PMIDA demonstrated excellent structural stability over multiple regeneration cycles, highlighting its potential for industrial application for REE recovery.
Freguia, S, Sharma, K, Benichou, O, Mulliss, M & Shon, HK 2021, 'Sustainable engineering of sewers and sewage treatment plants for scenarios with urine diversion', Journal of Hazardous Materials, vol. 415, pp. 125609-125609.
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Fu, Q, Wang, D, Li, X, Yang, Q, Xu, Q, Ni, B-J, Wang, Q & Liu, X 2021, 'Towards hydrogen production from waste activated sludge: Principles, challenges and perspectives', Renewable and Sustainable Energy Reviews, vol. 135, pp. 110283-110283.
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Hydrogen production from waste activated sludge (WAS) was widely considered and intensively investigated as a promising technology to recover energy from wastewater treatment plants. To date, no efforts have been made on either systematic summarization or critical thinking of the application niche of hydrogen production from WAS treatment. It is therefore time to evaluate whether and how to recover hydrogen in a future paradigm of WAS treatment. In this critical review, the principles and potentials, microorganisms, possible technologies, and process parameters of hydrogen generation were analyzed. Microbial electrolysis cell shows high theoretical hydrogen yield and could utilize a variety of organic compounds as substrates, which is regarded as a prospective technology for hydrogen production. However, the poor organics utilization and rapid consumptions of produced hydrogen hindered hydrogen recovery from WAS. Based on the analysis of the current state of the literatures, the opportunities and challenges of hydrogen production from WAS are rethought, the detailed knowledge gaps and perspective of hydrogen production from WAS were discussed, and the probable solutions of hydrogen recovery from WAS treatment are figured out. To guide the application and development of hydrogen recovery, a more promising avenue through rational integration of the available technologies to form a hybrid process is finally proposed. The integrated operational paradigm of WWTPs could achieve substantial technical, environmental and economic benefits. In addition, how this hybrid process works is illustrated, the challenges of this hybrid process and future efforts to be made in the future are put forward.
Fujise, L, Suggett, DJ, Stat, M, Kahlke, T, Bunce, M, Gardner, SG, Goyen, S, Woodcock, S, Ralph, PJ, Seymour, JR, Siboni, N & Nitschke, MR 2021, 'Unlocking the phylogenetic diversity, primary habitats, and abundances of free‐living Symbiodiniaceae on a coral reef', Molecular Ecology, vol. 30, no. 1, pp. 343-360.
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AbstractDinoflagellates of the family Symbiodiniaceae form mutualistic symbioses with marine invertebrates such as reef‐building corals, but also inhabit reef environments as free‐living cells. Most coral species acquire Symbiodiniaceae horizontally from the surrounding environment during the larval and/or recruitment phase, however the phylogenetic diversity and ecology of free‐living Symbiodiniaceae on coral reefs is largely unknown. We coupled environmental DNA sequencing and genus‐specific qPCR to resolve the community structure and cell abundances of free‐living Symbiodiniaceae in the water column, sediment, and macroalgae and compared these to coral symbionts. Sampling was conducted at two time points, one of which coincided with the annual coral spawning event when recombination between hosts and free‐living Symbiodiniaceae is assumed to be critical. Amplicons of the internal transcribed spacer (ITS2) region were assigned to 12 of the 15 Symbiodiniaceae genera or genera‐equivalent lineages. Community compositions were separated by habitat, with water samples containing a high proportion of sequences corresponding to coral symbionts of the genus Cladocopium, potentially as a result of cell expulsion from in hospite populations. Sediment‐associated Symbiodiniaceae communities were distinct, potentially due to the presence of exclusively free‐living species. Intriguingly, macroalgal surfaces displayed the highest cell abundances of Symbiodiniaceae, suggesting a key role for macroalgae in ensuring the ecological success of corals through maintenance of a continuum between environmental and symbiotic populations of Symbiodiniaceae.
Gao, L, Liu, G, Zamyadi, A, Wang, Q & Li, M 2021, 'Life-cycle cost analysis of a hybrid algae-based biological desalination – low pressure reverse osmosis system', Water Research, vol. 195, pp. 116957-116957.
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To fully understand the economic viability and implementation strategy of the emerging algae-based desalination technology, this study investigates the economic aspects of algae-based desalination system by comparing the life-cycle costs of three different scenarios: (1) a multi-stage microalgae based desalination system; (2) a hybrid desalination system based on the combination of microalgae and low pressure reverse osmosis (LPRO) system; and (3) a seawater reverse osmosis (SWRO) desalination system. It is identified that the capital expenditure (CAPEX) and operational expenditure (OPEX) of scenario 1 are significantly higher than those of scenarios 2 and 3, when algal biomass reuse is not taken into consideration. If the revenues obtained from the algal biomass reuse are taken into account, the OPEX of scenario 1 will decrease significantly, and scenarios 2 and 3 will have the highest and lowest OPEX, respectively. However, due to the high CAPEX of scenario 1, the total expenditure (TOTEX) of scenario 1 is still 27% and 33% higher than those of scenarios 2 and 3, respectively. A sensitivity study is undertaken to understand the effects of six key parameters on water total cost for different scenarios. It is suggested that the electricity unit price plays the most important role in determining the water total cost for different scenarios. An uncertainty analysis is also conducted to investigate the effects and limitations of the key assumptions made in this study. It is suggested that the assumption of total dissolved solids (TDS) removal efficiency of microalgae results in a high uncertainty of life-cycle cost analysis (LCCA). Additionally, it is estimated that 1.58 megaton and 0.30 megaton CO2 can be captured by the algae-based desalination process for scenarios 1 and 2, respectively, over 20 years service period, which could result in approximately AU $18 million and AU $3 million indirect financial benefits for scenarios 1 and 2, respectively. When...
Gao, X, Xu, Z, Li, Y, Zhang, L, Li, G, Nghiem, LD & Luo, W 2021, 'Bacterial dynamics for gaseous emission and humification in bio-augmented composting of kitchen waste', Science of The Total Environment, vol. 801, pp. 149640-149640.
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Gao, Y, Sun, S, Zhang, X, Liu, Y, Hu, J, Huang, Z, Gao, M & Pan, H 2021, 'Amorphous Dual‐Layer Coating: Enabling High Li‐Ion Conductivity of Non‐Sintered Garnet‐Type Solid Electrolyte', Advanced Functional Materials, vol. 31, no. 15, pp. 2009692-2009692.
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AbstractGarnet‐type oxide Li6.4La3Zr1.4Ta0.6O12 (LLZTO) has attracted considerable attention as a highly promising solid state electrolyte. However, its high ionic conductivity is achievable only after high temperature sintering (≈1200 °C) to form dense pellets but with detrimental brittleness and poor contact with electrodes. Herein, a novel strategy to achieve high Li+ ion conductivity of LLZTO without sintering is demonstrated. This is realized by ball milling LLZTO together with LiBH4, which results in a LLZTO composite with unique amorphous dual coating: LiBO2 as the inner layer and LiBH4 as the outer layer. After cold pressing the LLZTO composite powders under 300 MPa to form electrolyte pellets, a high Li+ ion conductivity of 8.02 × 10–5 S cm–1 is obtained at 30 °C, which is four orders of magnitude higher than that of the non‐sintered pristine LLZTO pellets (4.17 × 10–9 S cm–1). The composite electrolyte displays an ultrahigh Li+ transference number of 0.9999 and enables symmetric Li–Li cells to be cycled for 1000 h at 60 °C and 300 h at 30 °C. The significant improvements are attributed to the continuous ionic conductive network among LLZTO particles facilitated by LiBH4 that is chemically compatible and electrochemically stable with Li metal electrode.
Gao, Y, Sun, S, Zhang, X, Liu, Y, Hu, J, Huang, Z, Gao, M & Pan, H 2021, 'Solid State Electrolytes: Amorphous Dual‐Layer Coating: Enabling High Li‐Ion Conductivity of Non‐Sintered Garnet‐Type Solid Electrolyte (Adv. Funct. Mater. 15/2021)', Advanced Functional Materials, vol. 31, no. 15, pp. 2170100-2170100.
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Gaur, VK, Sharma, P, Gaur, P, Varjani, S, Ngo, HH, Guo, W, Chaturvedi, P & Singhania, RR 2021, 'Sustainable mitigation of heavy metals from effluents: Toxicity and fate with recent technological advancements', Bioengineered, vol. 12, no. 1, pp. 7297-7313.
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Increase in anthropogenic activities due to rapid industrialization had caused an elevation in heavy metal contamination of aquatic and terrestrial ecosystems. These pollutants have detrimental effects on human and environmental health. The majority of these pollutants are carcinogenic, neurotoxic, and are very poisonous even at very low concentrations. Contamination caused by heavy metals has become a global concern for which the traditional treatment approaches lack in providing a cost-effective and eco-friendly solution. Therefore, the use of microorganisms and plants to reduce the free available heavy metal present in the environment has become the most acceptable method by researchers. Also, in microbial- and phyto-remediation the redox reaction shifts the valence which makes these metals less toxic. In addition to this, the use of biochar as a remediation tool has provided a sustainable solution that needs further investigations toward its implementation on a larger scale. Enzymes secreted by microbes and whole microbial cell are considered an eco-efficient biocatalyst for mitigation of heavy metals from contaminated sites. To the best of our knowledge there is very less literature available covering remediation of heavy metals aspect along with the sensors used for detection of heavy metals. Systematic management should be implemented to overcome the technical and practical limitations in the use of these bioremediation techniques. The knowledge gaps have been identified in terms of its limitation and possible future directions have been discussed.
Gavhane, RS, Kate, AM, Soudagar, MEM, Wakchaure, VD, Balgude, S, Rizwanul Fattah, IM, Nik-Ghazali, N-N, Fayaz, H, Khan, TMY, Mujtaba, MA, Kumar, R & Shahabuddin, M 2021, 'Influence of Silica Nano-Additives on Performance and Emission Characteristics of Soybean Biodiesel Fuelled Diesel Engine', Energies, vol. 14, no. 5, pp. 1489-1489.
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The present study examines the effect of silicon dioxide (SiO2) nano-additives on the performance and emission characteristics of a diesel engine fuelled with soybean biodiesel. Soybean biofuel was prepared using the transesterification process. The morphology of nano-additives was studied using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The Ultrasonication process was used for the homogeneous blending of nano-additives with biodiesel, while surfactant was used for the stabilisation of nano-additives. The physicochemical properties of pure and blended fuel samples were measured as per ASTM standards. The performance and emissions characteristics of different fuel samples were measured at different loading conditions. It was found that the brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) increased by 3.48–6.39% and 5.81–9.88%, respectively, with the addition of SiO2 nano-additives. The carbon monoxide (CO), hydrocarbon (HC) and smoke emissions for nano-additive added blends were decreased by 1.9–17.5%, 20.56–27.5% and 10.16–23.54% compared to SBME25 fuel blends.
Ghanbari, F, Wang, Q, Hassani, A, Wacławek, S, Rodríguez-Chueca, J & Lin, K-YA 2021, 'Electrochemical activation of peroxides for treatment of contaminated water with landfill leachate: Efficacy, toxicity and biodegradability evaluation', Chemosphere, vol. 279, pp. 130610-130610.
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Contaminated water with landfill leachate (CWLL) with high salinity and high organic content (total organic carbon (TOC) = 649 mg/L and Chemical Oxygen Demand (COD) = 1175 mg/L) is a toxic and non-biodegradable effluent. The present research aimed to assess the treatment effectiveness of CWLL by electrocoagulation (EC)/oxidant process. The ferrous ions generated during the process were employed as coagulant and catalyst for the activation of different oxidants such as peroxymonosulfate (PMS), peroxydisulfate (PDS), hydrogen peroxide (HP), and percarbonate (PC) to decrease TOC in CWLL. Removal of ammonia, color, phosphorous, and chemical oxygen demand (COD) from CWLL effluent was explored at various processes. EC/HP had the best performance (∼73%) in mineralization of organic pollutants compared to others under the condition of pH 6.8, applied current of 200 mA, oxidant dosage of 6 mM, and time of 80 min. The oxidation priority was to follow this order: EC/HP > EC/PMS > EC/PDS > EC/PC. These processes enhanced the biodegradability of CWLL based on the average oxidation state and biochemical oxygen demand (BOD)/COD ratio. SUVA254 and E2/E3 indices were also investigated on obtained effluents. The phytotoxicity evaluation was carried out based on the germination index, indicating that the electro-activated oxidant was an effective system to reduce the toxicity of polluted waters. EC/HP showed supremacy compared to others in terms of efficiency, cost, and detoxification. Therefore, the electro-activated oxidant system is a good means for removing organic pollutants from real wastewater.
Ghobadi, R, Altaee, A, Zhou, JL, Karbassiyazdi, E & Ganbat, N 2021, 'Effective remediation of heavy metals in contaminated soil by electrokinetic technology incorporating reactive filter media', Science of The Total Environment, vol. 794, pp. 148668-148668.
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Soil contamination is increasingly a global problem with serious implications for human health. Among different soil decontamination approaches, electrokinetic (EK) remediation is a relatively new technology for treating organic and inorganic contaminants in soil. This research aims to develop an enhanced EK treatment method incorporating a compost-based reactive filter media (RFM) with the advantages of low-cost and strong affinity for heavy metals and test and improve the treatment efficiency for multiple heavy metals in natural soil. A series of EK operations were performed to investigate the performance of EK-RFM under different operating conditions such as the electric current and voltage, processing time, and the amount of RFM. The electric current and treatment time demonstrated a significant positive impact on removing Zn, Cd and Mn ions while changing the amount of RFM had an insignificant impact on the efficiency of heavy metals removal. Overall, 51.6%–72.1% removal of Zn, Cd, and Mn was achieved at 30.00 mA of electric current and 14 days of treatment duration. The energy consumption of the EK process was 0.17 kWh kg−1. The soil organic matter adversely affected the mobilization and migration of heavy metals such as Cu and Pb during EK treatment. The results are valuable in optimizing the design of the EK-RFM system, which will extend its application to field-scale soil decontamination practices.
Ghobadi, R, Altaee, A, Zhou, JL, McLean, P, Ganbat, N & Li, D 2021, 'Enhanced copper removal from contaminated kaolinite soil by electrokinetic process using compost reactive filter media', Journal of Hazardous Materials, vol. 402, pp. 123891-123891.
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Ghosh, B, Fatahi, B, Khabbaz, H, Nguyen, HH & Kelly, R 2021, 'Field study and numerical modelling for a road embankment built on soft soil improved with concrete injected columns and geosynthetics reinforced platform', Geotextiles and Geomembranes, vol. 49, no. 3, pp. 804-824.
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Gonzales, RR, Abdel-Wahab, A, Adham, S, Han, DS, Phuntsho, S, Suwaileh, W, Hilal, N & Shon, HK 2021, 'Salinity gradient energy generation by pressure retarded osmosis: A review', Desalination, vol. 500, pp. 114841-114841.
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Pressure retarded osmosis (PRO) has gained attention due to its use as a salinity gradient energy-generating membrane process. This process can convert difference in salinity between two streams into energy as it allows water transport through a semi-permeable membrane against the application of hydraulic pressure. This review provides a comprehensive look at the history and latest developments in preparation of membranes and modules for the PRO process, as well as the various applications of PRO. This review also explored the influence of feed characteristics and pretreatment strategies on water permeation and power generation during PRO operation. The current status and technological advancements of PRO as a process were reviewed, revealing how PRO can be operated as a stand-alone process or in integration with other hybrid processes. Despite the recent advancements in material and process development for PRO, membrane performance, wide-scale implementation, and commercialization efforts still leave much to be desired. Recognizing the current challenges facing the PRO technology, the advancements in PRO membrane and module development, and the various applications of the process, this review also draws out the future direction of PRO research and generation of osmotic salinity gradient energy as a viable energy source.
Gonzales, RR, Abdel-Wahab, A, Han, DS, Matsuyama, H, Phuntsho, S & Shon, HK 2021, 'Control of the antagonistic effects of heat-assisted chlorine oxidative degradation on pressure retarded osmosis thin film composite membrane surface', Journal of Membrane Science, vol. 636, pp. 119567-119567.
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During pressure retarded osmosis (PRO) operation, thin film composite (TFC) membranes are continuously exposed to chemicals present in the stream that can deteriorate the membrane's selective layer with exposure time. Following this observation, TFC membranes are placed in controlled oxidative degradation conditions using aqueous NaOCl solutions. Active chlorine, along with heat, can thin out the dense layer and, when controlled and optimized, can tune the membrane surface properties and separation efficiency as desirable for specific applications. The chlorine oxidative degradation is optimized in terms of chlorine exposure (a factor of both exposure time and chemical dosage), solution pH, and the subsequent heating time. After the chemical modification process, the membrane surface properties were characterized and the PRO performance as well as the osmotic energy harvesting capability were determined. The modified membranes exhibited different levels of polyamide degradation and increase in water permeability, which came along with decrease in selectivity. Optimization of the chlorine oxidative degradation using response surface methodology was performed to maximize the water permeability and extractable osmotic power while keeping salt rejection satisfactory. After performing chlorine oxidation at the following optimized conditions: 3025 ppm Cl2·h, pH 10.72, and 3 min heating time, initial non-pressure retarded water flux of 73.2 L m−2 h−1, specific reverse solute flux of 1.17 g L−1, and power density of 18.71 W m−2 (corresponding to water flux of 56.1 L m-2 h-1) at 12 bar were obtained using 0.6 M NaCl as draw and deionized water as feed.
Gonzales, RR, Zhang, L, Guan, K, Park, MJ, Phuntsho, S, Abdel-Wahab, A, Matsuyama, H & Shon, HK 2021, 'Aliphatic polyketone-based thin film composite membrane with mussel-inspired polydopamine intermediate layer for high performance osmotic power generation', Desalination, vol. 516, pp. 115222-115222.
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Gonzales, RR, Zhang, L, Sasaki, Y, Kushida, W, Matsuyama, H & Shon, HK 2021, 'Facile development of comprehensively fouling-resistant reduced polyketone-based thin film composite forward osmosis membrane for treatment of oily wastewater', Journal of Membrane Science, vol. 626, pp. 119185-119185.
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© 2021 Forward osmosis (FO) has proven to be a suitable process for treatment of problematic oily wastewater, due to its relatively higher water recovery rate and lower energy requirement, as opposed to pressure-driven membrane processes. Despite the lower membrane fouling propensity during FO operation, the development of comprehensively fouling-resistant membranes is further desired in FO as a suitable oily wastewater treatment process. In this current work, reduced aliphatic polyketone (rPK)-based thin film composite (TFC) membranes were developed. Reduction conditions using NaBH4 were tested, and the suitability of reduction was evaluated with membrane morphology, water wettability, and resistance to oil. The resultant rPK-TFC membrane, whose substrate was reduced with 0.5% (w/w) NaBH4 for 10 min, exhibited 37.8 L m−2 h−1 water flux in PRO mode. Using a foulant solution containing 1% (v/v) soybean oil, and 100 ppm humic acid, sodium alginate, and bovine serum albumin, the resultant rPK-TFC membrane maintained an outstanding 95% average flux recovery ratio, while the pristine PK-TFC membrane achieved an average flux recovery ratio of 67%. The results indicate that reduction of aliphatic polyketone is a facile method to develop membranes with outstanding water permeability and fouling resistance.
Graś, M, Kolanowski, Ł, Chen, Z, Lota, K, Jurak, K, Ryl, J, Ni, B-J & Lota, G 2021, 'Partial inhibition of borohydride hydrolysis using porous activated carbon as an effective method to improve the electrocatalytic activity of the DBFC anode', Sustainable Energy & Fuels, vol. 5, no. 17, pp. 4401-4413.
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Utilization of activated carbons from coffee waste in the complex borohydride electrooxidation process has great potential in increasing the efficiency of an anode based on the AB5-hydrogen storage alloy, as well as in proper management of waste.
Gul, M, Zulkifli, NWM, Kalam, MA, Masjuki, HH, Mujtaba, MA, Yousuf, S, Bashir, MN, Ahmed, W, Yusoff, MNAM, Noor, S, Ahmad, R & Hassan, MT 2021, 'RSM and Artificial Neural Networking based production optimization of sustainable Cotton bio-lubricant and evaluation of its lubricity & tribological properties', Energy Reports, vol. 7, pp. 830-839.
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Gunawan, Y, Putra, N, Hakim, II, Agustina, D & Mahlia, TMI 2021, 'Withering of tea leaves using heat pipe heat exchanger by utilizing low-temperature geothermal energy', International Journal of Low-Carbon Technologies, vol. 16, no. 1, pp. 146-155.
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Abstract The volume of Indonesian tea exports to the European Union (EU) decreased by 43% in 2014 because of the EU setting a maximum residue limit of anthraquinone (AQ) for tea as 0.02 mg/kg. The content of AQ in tea leaves increases when there is incomplete combustion in the combustion of firewood for the energy source of withering and drying of tea leaves. This study aims to develop and test a new concept for the direct use of low-temperature geothermal energy with a heat pipe heat exchanger (HPHE) for the withering of tea leaves as a solution for energy sources free from AQ. The geothermal fluid simulators use water, which is heated by heater and flowed by a pump. The HPHE used consists of 42 heat pipes and 181 fins. The heat pipe used has a length of 700 mm with an outer diameter of 10 mm. Each fin is made of aluminum with a thickness of 0.105 mm and a size of 76 × 345 mm2. The results show that the effectiveness of the HPHE varies from 66% to 79.59%. For 100 g of fresh tea leaves, the heating energy produced ranges from 15.21 W to 45.07 W, meaning it can wither tea leaves from 80% (w.b.) to 54% (w.b.) in a variety of 11 h 56 min to only 49.6 min. The Page mathematical model is the best model to represent the behavior of the tea leaves with this HPHE system.
Guo, W, Ngo, HH, Surampalli, RY & Zhang, TC 2021, 'Preface', Sustainable Resource Management: Technologies for Recovery and Reuse of Energy and Waste Materials, pp. xix-xx.
Hafiz, M, Alfahel, R, Hawari, AH, Hassan, MK & Altaee, A 2021, 'A Hybrid NF-FO-RO Process for the Supply of Irrigation Water from Treated Wastewater: Simulation Study', Membranes, vol. 11, no. 3, pp. 191-191.
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Municipal treated wastewater could be considered as a water source for food crop irrigation purposes. Enhancing the quality of treated wastewater to meet irrigation standards has become a necessary practice. Nanofiltration (NF) was used in the first stage to produce permeate at relatively low energy consumption. In the second stage, two membrane combinations were tested for additional water extraction from the brine generated by the NF process. The simulation results showed that using a hybrid forward osmosis (FO)–reverse osmosis (RO) system is more efficient than using the RO process alone for the further extraction of water from the brine generated by the NF process. The total specific energy consumption can be reduced by 27% after using FO as an intermediate process between NF and RO. In addition, the final permeate water quality produced using the hybrid FO-RO system was within the allowable standards for food crops irrigation.
Hafiz, M, Hawari, AH, Alfahel, R, Hassan, MK & Altaee, A 2021, 'Comparison of Nanofiltration with Reverse Osmosis in Reclaiming Tertiary Treated Municipal Wastewater for Irrigation Purposes', Membranes, vol. 11, no. 1, pp. 32-32.
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This study compares the performance of nanofiltration (NF) and reverse osmosis (RO) for the reclamation of ultrafiltered municipal wastewater for irrigation of food crops. RO and NF technologies were evaluated at different applied pressures; the performance of each technology was evaluated in terms of water flux, recovery rate, specific energy consumption and quality of permeate. It was found that the permeate from the reverse osmosis (RO) process complied with Food and Agriculture Organization (FAO) standards at pressures applied between 10 and 18 bar. At an applied pressure of 20 bar, the permeate quality did not comply with irrigation water standards in terms of chloride, sodium and calcium concentration. It was found that nanofiltration process was not suitable for the reclamation of wastewater as the concentration of chloride, sodium and calcium exceeded the allowable limits at all applied pressures. In the reverse osmosis process, the highest recovery rate was 36%, which was achieved at a pressure of 16 bar. The specific energy consumption at this applied pressure was 0.56 kWh/m3. The lowest specific energy of 0.46 kWh/m3 was achieved at an applied pressure of 12 bar with a water recovery rate of 32.7%.
Halat, DM, Snyder, RL, Sundararaman, S, Choo, Y, Gao, KW, Hoffman, ZJ, Abel, BA, Grundy, LS, Galluzzo, MD, Gordon, MP, Celik, H, Urban, JJ, Prendergast, D, Coates, GW, Balsara, NP & Reimer, JA 2021, 'Modifying Li+ and Anion Diffusivities in Polyacetal Electrolytes: A Pulsed-Field-Gradient NMR Study of Ion Self-Diffusion', Chemistry of Materials, vol. 33, no. 13, pp. 4915-4926.
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Han, C, Wang, X, Peng, J, Xia, Q, Chou, S, Cheng, G, Huang, Z & Li, W 2021, 'Recent Progress on Two-Dimensional Carbon Materials for Emerging Post-Lithium (Na+, K+, Zn2+) Hybrid Supercapacitors', Polymers, vol. 13, no. 13, pp. 2137-2137.
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The hybrid ion capacitor (HIC) is a hybrid electrochemical energy storage device that combines the intercalation mechanism of a lithium-ion battery anode with the double-layer mechanism of the cathode. Thus, an HIC combines the high energy density of batteries and the high power density of supercapacitors, thus bridging the gap between batteries and supercapacitors. Two-dimensional (2D) carbon materials (graphite, graphene, carbon nanosheets) are promising candidates for hybrid capacitors owing to their unique physical and chemical properties, including their enormous specific surface areas, abundance of active sites (surface and functional groups), and large interlayer spacing. So far, there has been no review focusing on the 2D carbon-based materials for the emerging post-lithium hybrid capacitors. This concept review considers the role of 2D carbon in hybrid capacitors and the recent progress in the application of 2D carbon materials for post-Li (Na+, K+, Zn2+) hybrid capacitors. Moreover, their challenges and trends in their future development are discussed.
Han, DS, Solayman, KMD, Shon, HK & Abdel-Wahab, A 2021, 'Pyrite (FeS2)-supported ultrafiltration system for removal of mercury (II) from water', Emergent Materials, vol. 4, no. 5, pp. 1441-1453.
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AbstractThis study investigated the Hg(II) removal efficiencies of the reactive adsorbent membrane (RAM) hybrid filtration process, a removal process that produces stable final residuals. The reaction mechanism between Hg(II) and pyrite and the rejection of the solids over time were characterized with respect to flux decline, pH change, and Hg and Fe concentration in permeate water. Effects of the presence of anions (Cl−, SO42−, NO3−) or humic acid (HA) on the rejection of the Hg(II)-contacted pyrite were studied. The presence of both HA and Hg(II) increased the rate of flux decline due to the formation of irreversible gel-like compact cake layers as shown in the experimental data and modeling related to the flux decline and the SEM images. Stability experiments of the final residuals retained on the membrane using a thiosulfate solution (Na2S2O3) show that the Hg(II)-laden solids were very stable due to little or no detection of Hg(II) in the permeate water. Experiment on the possibility of continuously removing Hg(II) by reusing the Hg/pyrite-laden membrane shows that almost all Hg(II) was adsorbed onto the pyrite surface regardless of the presence of salts or HA, and the Hg(II)-contacted pyrite residuals were completely rejected by the DE/UF system. Therefore, a membrane filter containing pyrite-Hg(II) could provide another reactive cake layer capable of further removal of Hg(II) without post-chemical treatment for reuse.
Han, R, Diao, J, Kumar, S, Lyalin, A, Taketsugu, T, Casillas, G, Richardson, C, Liu, F, Yoon, CW, Liu, H, Sun, X & Huang, Z 2021, 'Boron nitride for enhanced oxidative dehydrogenation of ethylbenzene', Journal of Energy Chemistry, vol. 57, pp. 477-484.
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Hannan, MA, Al-Shetwi, AQ, Ker, PJ, Begum, RA, Mansor, M, Rahman, SA, Dong, ZY, Tiong, SK, Mahlia, TMI & Muttaqi, KM 2021, 'Impact of renewable energy utilization and artificial intelligence in achieving sustainable development goals', Energy Reports, vol. 7, pp. 5359-5373.
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Hannan, MA, How, DNT, Lipu, MSH, Mansor, M, Ker, PJ, Dong, ZY, Sahari, KSM, Tiong, SK, Muttaqi, KM, Mahlia, TMI & Blaabjerg, F 2021, 'Deep learning approach towards accurate state of charge estimation for lithium-ion batteries using self-supervised transformer model', Scientific Reports, vol. 11, no. 1, p. 19541.
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AbstractAccurate state of charge (SOC) estimation of lithium-ion (Li-ion) batteries is crucial in prolonging cell lifespan and ensuring its safe operation for electric vehicle applications. In this article, we propose the deep learning-based transformer model trained with self-supervised learning (SSL) for end-to-end SOC estimation without the requirements of feature engineering or adaptive filtering. We demonstrate that with the SSL framework, the proposed deep learning transformer model achieves the lowest root-mean-square-error (RMSE) of 0.90% and a mean-absolute-error (MAE) of 0.44% at constant ambient temperature, and RMSE of 1.19% and a MAE of 0.7% at varying ambient temperature. With SSL, the proposed model can be trained with as few as 5 epochs using only 20% of the total training data and still achieves less than 1.9% RMSE on the test data. Finally, we also demonstrate that the learning weights during the SSL training can be transferred to a new Li-ion cell with different chemistry and still achieve on-par performance compared to the models trained from scratch on the new cell.
Hannan, MA, Wali, SB, Ker, PJ, Rahman, MSA, Mansor, M, Ramachandaramurthy, VK, Muttaqi, KM, Mahlia, TMI & Dong, ZY 2021, 'Battery energy-storage system: A review of technologies, optimization objectives, constraints, approaches, and outstanding issues', Journal of Energy Storage, vol. 42, pp. 103023-103023.
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Due to urbanization and the rapid growth of population, carbon emission is increasing, which leads to climate change and global warming. With an increased level of fossil fuel burning and scarcity of fossil fuel, the power industry is moving to alternative energy resources such as photovoltaic power (PV), wind power (WP), and battery energy-storage systems (BESS), among others. BESS has some advantages over conventional energy sources, which include fast and steady response, adaptability, controllability, environmental friendliness, and geographical independence, and it is considered as a potential solution to the global warming problem. This paper provides a comprehensive review of the battery energy-storage system concerning optimal sizing objectives, the system constraint, various optimization models, and approaches along with their advantages and weakness. Furthermore, for better understanding, the optimization objectives and methods have been classified into different categories. This paper also provides a detailed discussion on the BESS applications and explores the shortages of existing optimal BESS sizing algorithms to identify the gaps for future research. The issues and challenges are also highlighted to provide a clear idea to the researchers in the field of BESS. Overall, this paper conveys some significant recommendations that would be useful to the researchers and policymakers to structure a productive, powerful, efficient, and robust battery energy-storage system toward a future with a sustainable environment.
Hao, D, Chen, Z-G, Figiela, M, Stepniak, I, Wei, W & Ni, B-J 2021, 'Emerging alternative for artificial ammonia synthesis through catalytic nitrate reduction', Journal of Materials Science & Technology, vol. 77, pp. 163-168.
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Artificial catalytic synthesis of ammonia has become a hot research frontier in recent years. It is regarded as a promising approach that may replace the Haber-Bosch process and reduce global carbon dioxide emission. However, it is extremely difficult for the cleavage of nitrogen molecules under ambient conditions. Thus the ammonia yield rate is still low and the study is still limited in lab scale. If nitrites or nitrates are used as nitrogen sources, rather than nitrogen gas, the catalytic efficiency can be significantly improved, and the residual nitrate and nitrite contaminations in water systems can be efficiently eliminated and converted to energy sources at the same time. It is an emerging alternative for artificial ammonia synthesis, while there is not enough focus on the reduction of nitrate and nitrite. Herein, we systematically compared the differences between the reduction of nitrogen and nitrates, as well as listed the challenges in this area. The total conversion rate and energy efficiency of catalytic nitrate reduction are much higher than nitrogen gas reduction due to the much higher solubility and better converting pathway, which might be further enhanced by employing catalysts improvement strategies. Further, we also proposed suitable materials as well as a few future researches needs that may help boost the development of artificial ammonia synthesis using nitrate.
Hao, D, Huang, Q, Wei, W, Bai, X & Ni, B-J 2021, 'A reusable, separation-free and biodegradable calcium alginate/g-C3N4 microsphere for sustainable photocatalytic wastewater treatment', Journal of Cleaner Production, vol. 314, pp. 128033-128033.
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Graphitic carbon nitride (g-C3N4) is a metal-free photocatalyst with the advantages of facile preparation, low cost and good photocatalytic performance. However, as an extensively studied powder catalyst, it is though difficult to be recycled and reused which requires attention urgently. In this study, we report a facile preparation of g-C3N4 hydrogel microspheres with the cross-link reactions between sodium alginate and calcium ions, which can be simply removed from liquid for reuse. The hydroxyl of calcium alginate enabled to boost the adsorption of organic pollutants as well as to boost the transfer and separation of photogenerated charge carriers. The g-C3N4 hydrogel microspheres showed remarkable performance in the control of organic pollutant contamination. The sample 25%-SACN had the best photocatalytic activity, which can remove 80.94% MB in 42 h. The total removal is 1.77 times as that of 0%-SACN. Meanwhile, it had good cycle stability and the catalytic performance did not decrease after 5-time usage. The used g-C3N4 hydrogel microspheres were also demonstrated to be biodegraded anaerobically to produce methane for energy recovery and recycling. The results and outcome of this paper might bring new inspiration for the study of easily reusable and sustainable photocatalysts for wastewater treatment.
Hao, D, Liu, Y, Gao, S, Arandiyan, H, Bai, X, Kong, Q, Wei, W, Shen, PK & Ni, B-J 2021, 'Emerging artificial nitrogen cycle processes through novel electrochemical and photochemical synthesis', Materials Today, vol. 46, pp. 212-233.
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The nitrogen cycle is an important part of the global biogeochemical cycle, while the human activities have already caused a severe imbalance of the global nitrogen cycle. In this review, we proposed a new generation of artificial nitrogen cycle via electrochemical and photocatalytic reactions. In details, the N2 from the air, NO3−/NO2− containing wastewater, nitrogen oxides from vehicle emission are all able to be utilized as a nitrogen source for the synthesis of NH3 under ambient conditions. The oxidation of NH3, N2 and nitrogen oxides can all achieve the aim of obtaining NO3−. Hydrazine can also be synthesized electrochemical and photochemical reactions. Utilizing electrochemical and photocatalytic processes enables to eliminate the hazardous of nitrogen-containing organic chemicals, and some inorganic nitrogen polluted wastewater. More importantly, coupling N-based reaction with other reaction like CO2 reduction enables to synthesize some high-value chemicals such as urea. Then we highlighted some recent achievements in these reactions and proposed some future potential developing directions. The results and funding of this work may help us develop highly efficient catalysts and strategies for the artificial nitrogen cycle, repairing the broken nitrogen cycle balance.
Hao, D, Ren, J, Wang, Y, Arandiyan, H, Garbrecht, M, Bai, X, Shon, HK, Wei, W & Ni, B-J 2021, 'A Green Synthesis of Ru Modified g-C 3 N 4 Nanosheets for Enhanced Photocatalytic Ammonia Synthesis', Energy Material Advances, vol. 2021, pp. 1-12.
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Nitrate is a crucial environmental pollutant, and its risk on ecosystem keeps increasing. Photocatalytic conversion of nitrate to ammonia can simultaneously achieve the commercialization of environmental hazards and recovery of valuable ammonia, which is green and sustainable for the planet. However, due to the thermodynamic and kinetic energy barriers, photocatalytic nitrate reduction usually involves a higher selectivity of the formation of nitrogen that largely limits the ammonia synthesis activity. In this work, we reported a green and facile synthesis of novel metallic ruthenium particle modified graphitic carbon nitride photocatalysts. Compare with bulk graphitic carbon nitride, the optimal sample had 2.93-fold photocatalytic nitrate reduction to ammonia activity (2.627 mg/h/g cat ), and the NH 3 selectivity increased from 50.77% to 77.9%. According to the experimental and calculated results, the enhanced photocatalytic performance is attributed to the stronger light absorption, nitrate adsorption, and lower energy barrier for the generation of ammonia. This work may provide a facile way to prepare metal modified photocatalysts to achieve highly efficient nitrate reduction to ammonia.
Harari, PA, Banapurmath, NR, Yaliwal, VS, Khan, TMY, Badruddin, IA, Kamangar, S & Mahlia, TMI 2021, 'Effect of Injection Timing and Injection Duration of Manifold Injected Fuels in Reactivity Controlled Compression Ignition Engine Operated with Renewable Fuels', Energies, vol. 14, no. 15, pp. 4621-4621.
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In the current work, an effort is made to study the influence of injection timing (IT) and injection duration (ID) of manifold injected fuels (MIF) in the reactivity controlled compression ignition (RCCI) engine. Compressed natural gas (CNG) and compressed biogas (CBG) are used as the MIF along with diesel and blends of Thevetia Peruviana methyl ester (TPME) are used as the direct injected fuels (DIF). The ITs of the MIF that were studied includes 45° ATDC, 50° ATDC, and 55° ATDC. Also, present study includes impact of various IDs of the MIF such as 3, 6, and 9 ms on RCCI mode of combustion. The complete experimental work is conducted at 75% of rated power. The results show that among the different ITs studied, the D+CNG mixture exhibits higher brake thermal efficiency (BTE), about 29.32% is observed at 50° ATDC IT, which is about 1.77, 3.58, 5.56, 7.51, and 8.54% higher than D+CBG, B20+CNG, B20+CBG, B100+CNG, and B100+CBG fuel combinations. The highest BTE, about 30.25%, is found for the D+CNG fuel combination at 6 ms ID, which is about 1.69, 3.48, 5.32%, 7.24, and 9.16% higher as compared with the D+CBG, B20+CNG, B20+CBG, B100+CNG, and B100+CBG fuel combinations. At all ITs and IDs, higher emissions of nitric oxide (NOx) along with lower emissions of smoke, carbon monoxide (CO), and hydrocarbon (HC) are found for D+CNG mixture as related to other fuel mixtures. At all ITs and IDs, D+CNG gives higher In-cylinder pressure (ICP) and heat release rate (HRR) as compared with other fuel combinations.
Hasan, MH, Mahlia, TMI, Mofijur, M, Rizwanul Fattah, IM, Handayani, F, Ong, HC & Silitonga, AS 2021, 'A Comprehensive Review on the Recent Development of Ammonia as a Renewable Energy Carrier', Energies, vol. 14, no. 13, pp. 3732-3732.
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Global energy sources are being transformed from hydrocarbon-based energy sources to renewable and carbon-free energy sources such as wind, solar and hydrogen. The biggest challenge with hydrogen as a renewable energy carrier is the storage and delivery system’s complexity. Therefore, other media such as ammonia for indirect storage are now being considered. Research has shown that at reasonable pressures, ammonia is easily contained as a liquid. In this form, energy density is approximately half of that of gasoline and ten times more than batteries. Ammonia can provide effective storage of renewable energy through its existing storage and distribution network. In this article, we aimed to analyse the previous studies and the current research on the preparation of ammonia as a next-generation renewable energy carrier. The study focuses on technical advances emerging in ammonia synthesis technologies, such as photocatalysis, electrocatalysis and plasmacatalysis. Ammonia is now also strongly regarded as fuel in the transport, industrial and power sectors and is relatively more versatile in reducing CO2 emissions. Therefore, the utilisation of ammonia as a renewable energy carrier plays a significant role in reducing GHG emissions. Finally, the simplicity of ammonia processing, transport and use makes it an appealing choice for the link between the development of renewable energy and demand.
Hazrat, MA, Rasul, MG, Khan, MMK, Mofijur, M, Ahmed, SF, Ong, HC, Vo, D-VN & Show, PL 2021, 'Techniques to improve the stability of biodiesel: a review', Environmental Chemistry Letters, vol. 19, no. 3, pp. 2209-2236.
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He, D, Xiao, J, Wang, D, Liu, X, Fu, Q, Li, Y, Du, M, Yang, Q, Liu, Y, Wang, Q, Ni, B-J, Song, K, Cai, Z, Ye, J & Yu, H 2021, 'Digestion liquid based alkaline pretreatment of waste activated sludge promotes methane production from anaerobic digestion', Water Research, vol. 199, pp. 117198-117198.
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This work proved an efficient method to significantly increase methane production from anaerobic digestion of WAS. This method is to reflux proper of digestion liquid into waste activated sludge pretreatment unit (pH 9.5 for 24 h). The yield of maximum methane improved between 174.2 ± 7.3 and 282.5 ± 14.1 mL/g VSS with the reflux ratio of digestion liquid increasing from 0% to 20%. It was observed that the biodegradable organics in the digestion liquid did not affect the biological processes related to anaerobic digestion but increased methane production through reutilization. The ammonium in the digestion liquid was the main contributor to the increase in methane production via promoting sludge solubilization, but refractory organics were the major inhibitors to anaerobic digestion. It should be emphasized that the metal ions present in the digestion liquid were beneficial rather than harmful to the biological processes in the anaerobic digestion, which may be connected with the fact that certain metal ions were involved in the expression and activation of key enzymes. In addition, it was found that anaerobes in digestion liquid were another potential contributor to the enhanced anaerobic digestion.
He, D, Xiao, J, Wang, D, Liu, X, Li, Y, Fu, Q, Li, C, Yang, Q, Liu, Y & Ni, B-J 2021, 'Understanding and regulating the impact of tetracycline to the anaerobic fermentation of waste activated sludge', Journal of Cleaner Production, vol. 313, pp. 127929-127929.
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Tetracycline (TC), a widely used antibiotic, was enriched in waste activated sludge (WAS) at significant levels. However, the TC impact on WAS anaerobic fermentation are still poorly understood. This work aims to analyze the effect of TC to the WAS anaerobic fermentation by investigating the differences of sludge properties, short-chain fatty acids (SCFAs) production and microbial community abundance. The results showed that the environmental level of TC had no effect on the SCFAs production, but with the further increase of the content of TC to 60 mg/kg TSS, the maximum SCFAs yield decreased from 125.1 ± 3.2 to 90.8 ± 1.7 mg COD/g VSS. Mechanism exploration indicated that TC had no significant effect on solubilization, hydrolysis and homoacetogenesis processes, but severely inhibited acidogenesis, acetogenesis and methanogenesis processes. Microbial analysis showed that the presence of TC reduced the diversity of microbial communities and the abundance of functional microorganisms relevant to SCFAs production and complex organic degradation, such as Proteiniclasticun and Novosphingobium. This negative effect was persistent because only a small amount of TC can be degraded in the anaerobic fermentation process. Hence, CaO2 was proposed and studied as a regulation strategy that can reduce the toxicity of TC on anaerobic fermentation.
Herdean, A, Hall, CC, Pham, LL, Macdonald Miller, S, Pernice, M & Ralph, PJ 2021, 'Action Spectra and Excitation Emission Matrices reveal the broad range of usable photosynthetic active radiation for Phaeodactylum tricornutum', Biochimica et Biophysica Acta (BBA) - Bioenergetics, vol. 1862, no. 9, pp. 148461-148461.
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Hoang, AT, Nižetić, S, Ong, HC, Mofijur, M, Ahmed, SF, Ashok, B, Bui, VTV & Chau, MQ 2021, 'Insight into the recent advances of microwave pretreatment technologies for the conversion of lignocellulosic biomass into sustainable biofuel', Chemosphere, vol. 281, pp. 130878-130878.
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The utilization of renewable lignocellulosic biomasses for bioenergy synthesis is believed to facilitate competitive commercialization and realize affordable clean energy sources in the future. Among the pathways for biomass pretreatment methods that enhance the efficiency of the whole biofuel production process, the combined microwave irradiation and physicochemical approach is found to provide many economic and environmental benefits. Several studies on microwave-based pretreatment technologies for biomass conversion have been conducted in recent years. Although some reviews are available, most did not comprehensively analyze microwave-physicochemical pretreatment techniques for biomass conversion. The study of these techniques is crucial for sustainable biofuel generation. Therefore, the biomass pretreatment process that combines the physicochemical method with microwave-assisted irradiation is reviewed in this paper. The effects of this pretreatment process on lignocellulosic structure and the ratio of achieved components were also discussed in detail. Pretreatment processes for biomass conversion were substantially affected by temperature, irradiation time, initial feedstock components, catalyst loading, and microwave power. Consequently, neoteric technologies utilizing high efficiency-based green and sustainable solutions should receive further focus. In addition, methodologies for quantifying and evaluating effects and relevant trade-offs should be develop to facilitate the take-off of the biofuel industry with clean and sustainable goals.
Hoang, AT, Ong, HC, Fattah, IMR, Chong, CT, Cheng, CK, Sakthivel, R & Ok, YS 2021, 'Progress on the lignocellulosic biomass pyrolysis for biofuel production toward environmental sustainability', Fuel Processing Technology, vol. 223, pp. 106997-106997.
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The increasing energy demand and diminishing fossil fuel sources have called for the exploration of new energy sources. To satisfy growing global energy demand and accomplish sustainable energy development goals, biomass plays an essential role in present and future energy. Pyrolysis holds considerable potential approaches among biomass conversion technologies. This study presents a critical review of the effect of the key pyrolysis parameters from lignocellulosic biomass to product distribution. The lignocellulosic biomass composition and pyrolysis conversion behavior of every single component was discussed in detail. On top of that, CO2-based benefits, economic assessment, and technical orientation for biofuel production from biomass are included. The carbon and hydrogen content of biomass is critical for producing high-quality bio-oil. When compared to other energy crops and agricultural residues, pyrolysis of clean wood and polar demonstrated the best bio-oil production. The increased cellulose and hemicellulose content aiding in the synthesis of bio-oil, but the high concentration of lignin results in more biochar. The article delves into product upgrading via several routes such as physical, chemical, and catalytic. From the review, considering factors such as pyrolysis technologies, energy demand, and bio-oil yields, greenhouse potential benefits needs to be evaluated, and this needs to be done on an individual basis. In terms of production cost, the current cost of biomass feedstock can range between $50 to $97/ton, which is approximately 30−54% of the liquid fuel production cost. A wide range of studies covering different aspects of biomass pyrolysis technology, from reactor configuration and the heating source to single and poly-step pyrolysis processes, have been carried out in the search for solutions in optimizing the current technologies. Thus, expanding and improving awareness of the lignocellulosic biomass in the pyrolysis technology wou...
Hoang, H-G, Lin, C, Chiang, C-F, Bui, X-T, Lukkhasorn, W, Bui, T-P-T, Tran, H-T, Vo, T-D-H, Le, V-G & Nghiem, LD 2021, 'The Individual and Synergistic Indexes for Assessments of Heavy Metal Contamination in Global Rivers and Risk: a Review', Current Pollution Reports, vol. 7, no. 3, pp. 247-262.
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Holland, MM, Everett, JD, Cox, MJ, Doblin, MA & Suthers, IM 2021, 'Pelagic forage fish distribution in a dynamic shelf ecosystem – Thermal demands and zooplankton prey distribution', Estuarine, Coastal and Shelf Science, vol. 249, pp. 107074-107074.
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Hossain Lipu, MS, Hannan, MA, Karim, TF, Hussain, A, Saad, MHM, Ayob, A, Miah, MS & Indra Mahlia, TM 2021, 'Intelligent algorithms and control strategies for battery management system in electric vehicles: Progress, challenges and future outlook', Journal of Cleaner Production, vol. 292, pp. 126044-126044.
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Globally, the research on battery technology in electric vehicle applications is advancing tremendously to address the carbon emissions and global warming issues. The effectiveness of electric vehicles depends on the accurate assessment of key parameters as well as proper functionality and diagnosis of the battery storage system. However, poor monitoring and safety strategies of the battery storage system can lead to critical issues such as battery overcharging, over-discharging, overheating, cell unbalancing, thermal runaway, and fire hazards. To address these concerns, an effective battery management system plays a crucial role in enhancing battery performance including precise monitoring, charging-discharging control, heat management, battery safety, and protection. The goal of this paper is to deliver a comprehensive review of different intelligent approaches and control schemes of the battery management system in electric vehicle applications. In line with that, the review evaluates the intelligent algorithms in battery state estimation concerning their features, structure, configuration, accuracy, advantages, and disadvantages. Moreover, the review explores the various controllers in battery heating, cooling, equalization, and protection highlighting categories, characteristics, targets, achievements, benefits, and shortcomings. The key issues and challenges in terms of computation complexity, execution problems along with various internal and external factors are identified. Finally, future opportunities and directions are delivered to design an efficient intelligent algorithm and controller toward the development of an advanced battery management system for future sustainable electric vehicle applications.
Hossain, N, Hoong, LL, Barua, P, Soudagar, MEM & Mahlia, TMI 2021, 'The effect of enzymatic hydrolysis of pretreated wastepaper for bioethanol production', Korean Journal of Chemical Engineering, vol. 38, no. 12, pp. 2493-2499.
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Enzymatic hydrolysis of waste biomass for bioethanol production is considered a decades old traditional, inexpensive, and energy-effective approach. In this study, waste office paper was pretreated with diluted sulfuric acid (H2SO4) and hydrolyzed with one of the most available and cost-effective enzymes, cellulase derived from Trichoderma reesei, under submerged static condition. Three different pretreatment approaches—cut into 2 cm2, blended with distilled water, and pretreated with diluted H2SO4—have been implemented, and pretreatment with diluted H2SO4 was the most effective. Hydrolysis with different concentrations—0.5 M, 1.0 M, 1.5 M, 2.0 M of H2SO4—was performed. The maximum glucose content was obtained at 2.0 M H2SO4 at 90 min reaction time, and glucose yield was 0.11 g glucose/g wastepaper. The cut paper, wet-blended, and acid-treated wastepaper was hydrolyzed with cellulase enzyme for 2, 4, and 5 consecutive days with 5 mg, 10 mg, 15 mg, and 20 mg enzyme loadings. The maximum glucose content obtained was 9.75 g/l from acid-treated wastepaper, after 5 days of enzymatic hydrolysis with 20 mg enzyme loading and a glucose yield of a 0.5 g glucose/g wastepaper. The wastepaper hydrolysate was further fermented for 6, 8, and 10 hours continuously with Saccharomyces cerevisiae (yeast), and at 10 hours of fermentation, the maximum glucose consumption was 0.18 g by yeast. Further, HPLC analysis of the fermented medium presented a strong peak of bioethanol content at 16.12 min. The distillation of bioethanol by rotary evaporator presented 0.79 ml bioethanol/fermented solution, which indicated the conversion efficiency of 79%.
Hossain, N, Mahlia, TMI, Miskat, MI, Chowdhury, T, Barua, P, Chowdhury, H, Nizamuddin, S, Ahmad, NB, Zaharin, NAB, Mazari, SA & Soudagar, MEM 2021, 'Bioethanol production from forest residues and life cycle cost analysis of bioethanol-gasoline blend on transportation sector', Journal of Environmental Chemical Engineering, vol. 9, no. 4, pp. 105542-105542.
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Hossain, SM, Park, H, Kang, H-J, Mun, JS, Tijing, L, Rhee, I, Kim, J-H, Jun, Y-S & Shon, HK 2021, 'Facile synthesis and characterization of anatase TiO2/g-CN composites for enhanced photoactivity under UV–visible spectrum', Chemosphere, vol. 262, pp. 128004-128004.
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© 2020 Elsevier Ltd For the purpose of atmospheric NO removal, anatase TiO2/g-CN photocatalytic composites were prepared by using a facile template-free calcination route in atmospheric conditions. Considerably fiscal NP400 and laboratory-grade melamine were used as the precursor of the composites. Additionally, samples were prepared with different wt. ratios of TiO2 and melamine by using two distinct calcination temperatures (550 °C/600 °C). The morphological attributes of the composites were assessed with X-ray diffraction, scanning and transmission electron microscopy, infrared spectroscopy, and X-ray photoelectron spectroscopy. Additionally, the optical traits were evaluated and compared using UV–visible diffuse reflectance spectroscopy and photoluminescence analysis. Finally, the photodegradation potentials for atmospheric NO by using the as-prepared composites were assessed under both UV and visible light irradiation. All the composites showed superior NO oxidation compared to NP400 and bulk g-CN. For the composites prepared by using the calcination temperature of 550 °C, the maximum NO removal was observed when the NP400 to melamine ratio was 1:2, irrespective of the utilized light irradiation type. Whereas for increased calcination temperature (600 °C), the maximum NO removal was observed at the precursor mix ratio of 1:3 (NP400:melamine). Successfully narrowed energy bandgaps were perceived in the as-prepared composites. Moreover, a subsequent drop in NO2 generation during NO oxidation was observed under both UV and visible light irradiation. Interestingly, higher calcination temperature during the synthesis of the catalysts has shown a significant drop in NO2 generation during the photodegradation of NO.
Hossain, SM, Park, H, Kang, H-J, Mun, JS, Tijing, L, Rhee, I, Kim, J-H, Jun, Y-S & Shon, HK 2021, 'Synthesis and NOx removal performance of anatase S–TiO2/g-CN heterojunction formed from dye wastewater sludge', Chemosphere, vol. 275, pp. 130020-130020.
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In this study, sludges generated from Ti-based flocculation of dye wastewater were used to retrieve photoactive titania (S-TiO2). It was heterojunctioned with graphitic carbon nitride (g-CN) to augment photoactivity under UV/visible light irradiance. Later the as-prepared samples were utilized to remove nitrogen oxides (NOx) in the atmospheric condition through photocatalysis. Heterojunction between S-TiO2 and g-CN was prepared through facile calcination (@550 °C) of S-TiO2 and melamine mix. Advanced sample characterization was carried out and documented extensively. Successful heterojunction was confirmed from the assessment of morphological and optical attributes of the samples. Finally, the prepared samples' level of photoactivity was assessed through photooxidation of NOx under both UV and visible light irradiance. Enhanced photoactivity was observed in the prepared samples irrespective of the light types. After 1 h of UV/visible light-based photooxidation, the best sample STC4 was found to remove 15.18% and 9.16% of atmospheric NO, respectively. In STC4, the mixing ratio of S-TiO2, to melamine was maintained as 1:3. Moreover, the optical bandgap of STC4 was found as 2.65 eV, where for S-TiO2, it was 2.83 eV. Hence, the restrained rate of photogenerated charge recombination and tailored energy bandgap of the as-prepared samples were the primary factors for enhancing photoactivity.
Hosseinzadeh, A, Najafpoor, AA, Navaei, AA, Zhou, JL, Altaee, A, Ramezanian, N, Dehghan, A, Bao, T & Yazdani, M 2021, 'Improving Formaldehyde Removal from Water and Wastewater by Fenton, Photo-Fenton and Ozonation/Fenton Processes through Optimization and Modeling', Water, vol. 13, no. 19, pp. 2754-2754.
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This study aimed to assess, optimize and model the efficiencies of Fenton, photo-Fenton and ozonation/Fenton processes in formaldehyde elimination from water and wastewater using the response surface methodology (RSM) and artificial neural network (ANN). A sensitivity analysis was used to determine the importance of the independent variables. The influences of different variables, including H2O2 concentration, initial formaldehyde concentration, Fe dosage, pH, contact time, UV and ozonation, on formaldehyde removal efficiency were studied. The optimized Fenton process demonstrated 75% formaldehyde removal from water. The best performance with 80% formaldehyde removal from wastewater was achieved using the combined ozonation/Fenton process. The developed ANN model demonstrated better adequacy and goodness of fit with a R2 of 0.9454 than the RSM model with a R2 of 0. 9186. The sensitivity analysis showed pH as the most important factor (31%) affecting the Fenton process, followed by the H2O2 concentration (23%), Fe dosage (21%), contact time (14%) and formaldehyde concentration (12%). The findings demonstrated that these treatment processes and models are important tools for formaldehyde elimination from wastewater.
Hosseinzadeh, A, Zhou, JL, Navidpour, AH & Altaee, A 2021, 'Progress in osmotic membrane bioreactors research: Contaminant removal, microbial community and bioenergy production in wastewater', Bioresource Technology, vol. 330, pp. 124998-124998.
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Renewable energy, water conservation, and environmental protection are the most important challenges today. Osmotic membrane bioreactor (OMBR) is an innovative process showing superior performance in bioenergy production, eliminating contaminants, and low fouling tendency. However, salinity build-up is the main drawback of this process. Identifying the microbial community can improve the process in bioenergy production and contaminant treatment. This review aims to study the recent progress and challenges of OMBRs in contaminant removal, microbial communities and bioenergy production. OMBRs are widely reported to remove over 80% of total organic carbon, PO43-, NH4+ and emerging contaminants from wastewater. The most important microbial phyla for both hydrogen and methane production in OMBR are Firmicutes, Proteobacteria and Bacteroidetes. Firmicutes' dominance in anaerobic processes is considerably increased from usually 20% at the beginning to 80% under stable condition. Overall, OMBR process has great potential to be applied for simultaneous bioenergy production and wastewater treatment.
Huang, Q, Wang, C, Hao, D, Wei, W, Wang, L & Ni, B-J 2021, 'Ultralight biodegradable 3D-g-C3N4 aerogel for advanced oxidation water treatment driven by oxygen delivery channels and triphase interfaces', Journal of Cleaner Production, vol. 288, pp. 125091-125091.
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The development of highly efficient and separation-free, low-cost photocatalysts have crucial prospect for sustainable wastewater treatment, because it is able to eliminate the hazards of organic pollutant with facile operation. However, the relatively high cost of previous photocatalysts highly obstructs the application of these materials. Herein, we report a cost-effective and distinct konjac/graphitic carbon nitride (KCN) aerogel, which has superior performance for advanced oxidation water treatment. The abundant porous structure of the ultralight aerogel ensures the rapid adsorption of pollutants, which is much helpful for the further photodegradation process. During the working process, the aerogel is half submerged in pollutant solution and half exposed in air, forming a distinctive gas-solid-liquid triphase system, where oxygen can be rapidly delivered into the solution via the porous channels, boosting the generation of hydroxyl and superoxide radicals. Meanwhile, the aerogel structure can separate the g-C3N4, obstruct its stacking, as well as improve the light absorption rate. The synthesis, utilization and readily biodegradable treatment of the KCN aerogels are all green and eco-friendly, which is extremely constructive for strategies to develop novel highly efficient photocatalytic materials.
Huang, Q-S, Wei, W & Ni, B-J 2021, 'Catalysts derived from Earth-abundant natural biomass enable efficient photocatalytic CO2conversion for achieving a closed-loop carbon cycle', Green Chemistry, vol. 23, no. 23, pp. 9683-9692.
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A one-pot, facile, sulfuric-acid-assisted carbonization method was developed to fabricate a series of biomass-derived metal-free carbonaceous photocatalysts for high performance CO2conversion, which satisfied a closed-loop carbon cycle.
Huang, Y, Lei, C, Liu, C-H, Perez, P, Forehead, H, Kong, S & Zhou, JL 2021, 'A review of strategies for mitigating roadside air pollution in urban street canyons', Environmental Pollution, vol. 280, pp. 116971-116971.
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Urban street canyons formed by high-rise buildings restrict the dispersion of vehicle emissions, which pose severe health risks to the public by aggravating roadside air quality. However, this issue is often overlooked in city planning. This paper reviews the mechanisms controlling vehicle emission dispersion in urban street canyons and the strategies for managing roadside air pollution. Studies have shown that air pollution hotspots are not all attributed to heavy traffic and proper urban design can mitigate air pollution. The key factors include traffic conditions, canyon geometry, weather conditions and chemical reactions. Two categories of mitigation strategies are identified, namely traffic interventions and city planning. Popular traffic interventions for street canyons include low emission zones and congestion charges which can moderately improve roadside air quality. In comparison, city planning in terms of building geometry can significantly promote pollutant dispersion in street canyons. General design guidelines, such as lower canyon aspect ratio, alignment between streets and prevailing winds, non-uniform building heights and ground-level building porosity, may be encompassed in new development. Concurrently, in-street barriers are widely applicable to rectify the poor roadside air quality in existing street canyons. They are broadly classified into porous (e.g. trees and hedges) and solid (e.g. kerbside parked cars, noise fences and viaducts) barriers that utilize their aerodynamic advantages to ease roadside air pollution. Post-evaluations are needed to review these strategies by real-world field experiments and more detailed modelling in the practical perspective.
Huang, Y, Ng, ECY, Zhou, JL, Surawski, NC, Lu, X, Du, B, Forehead, H, Perez, P & Chan, EFC 2021, 'Impact of drivers on real-driving fuel consumption and emissions performance', Science of The Total Environment, vol. 798, pp. 149297-149297.
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Eco-driving has attracted great attention as a cost-effective and immediate measure to reduce fuel consumption significantly. Understanding the impact of driver behaviour on real driving emissions (RDE) is of great importance for developing effective eco-driving devices and training programs. Therefore, this study was conducted to investigate the performance of different drivers using a portable emission measurement system. In total, 30 drivers, including 15 novice and 15 experienced drivers, were recruited to drive the same diesel vehicle on the same route, to minimise the effect of uncontrollable real-world factors on the performance evaluation. The results show that novice drivers are less skilled or more aggressive than experienced drivers in using the accelerator pedal, leading to higher vehicle and engine speeds. As a result, fuel consumption rates of novice drivers vary in a slightly greater range than those of experienced drivers, with a marginally higher (2%) mean fuel consumption. Regarding pollutant emissions, CO and THC emissions of all drivers are well below the standard limits, while NOx and PM emissions of some drivers significantly exceed the limits. Compared with experienced drivers, novice drivers produce 17% and 29% higher mean NOx and PM emissions, respectively. Overall, the experimental results reject the hypothesis that driver experience has significant impacts on fuel consumption performance. The real differences lie in the individual drivers, as the worst performing drivers have significantly higher fuel consumption rates than other drivers, for both novice and experienced drivers. The findings suggest that adopting eco-driving skills could deliver significant reductions in fuel consumption and emissions simultaneously for the worst performing drivers, regardless of driving experience.
Huang, Y, Surawski, NC, Zhuang, Y, Zhou, JL & Hong, G 2021, 'Dual injection: An effective and efficient technology to use renewable fuels in spark ignition engines', Renewable and Sustainable Energy Reviews, vol. 143, pp. 110921-110921.
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Modern spark ignition engines mostly use one injection system to deliver gasoline into the combustion chamber, using either direct injection or port fuel injection. Both technologies have their respective advantages. To integrate their advantages and to promote the use of renewable fuels, dual injection engines are in development in recent years. Dual injection represents an advanced combustion system and is a novel technology to address the urgent issues of sustainability and environmental protection. This study reviews the state-of-the-art research on dual injection spark ignition engines with a focus on renewable fuels, their advantages and engine performance. The main advantages of dual injection include greater control flexibility, enhanced cooling effect, knock mitigation, engine downsizing, extended lean-burn limits, higher thermal efficiency and reductions of several emission species. The most promising renewable fuels for dual injection are ethanol, methanol and hydrogen. Each renewable fuel is aimed at different advantages of dual injection. Alcohol-gasoline dual injection provides great anti-knock ability by taking advantage of alcohols' large enthalpies of vaporisation and high octane numbers, while hydrogen-gasoline dual injection provides extended lean-burn limits by taking advantage of hydrogen's low ignition energy, wide flammability limit and high flame speed. Direct injection of renewable fuels is the optimal injection strategy because it effectively utilises the strong cooling effect of alcohols or avoids the volumetric efficiency reduction and pre-ignition of hydrogen. Dual injection generally demonstrates higher thermal efficiency than single injection. In addition, dual injection effectively reduces particulate emissions while there are usually trade-offs among gaseous emissions.
Hughes, DJ, Giannini, FC, Ciotti, AM, Doblin, MA, Ralph, PJ, Varkey, D, Verma, A & Suggett, DJ 2021, 'Taxonomic Variability in the Electron Requirement for Carbon Fixation Across Marine Phytoplankton', Journal of Phycology, vol. 57, no. 1, pp. 111-127.
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Fast Repetition Rate fluorometry (FRRf) has been increasingly used to measure marine primary productivity by oceanographers to understand how carbon (C) uptake patterns vary over space and time in the global ocean. As FRRf measures electron transport rates through photosystem II (ETRPSII), a critical, but difficult to predict conversion factor termed the “electron requirement for carbon fixation” (Φe,C) is needed to scale ETRPSII to C‐fixation rates. Recent studies have generally focused on understanding environmental regulation of Φe,C, while taxonomic control has been explored by only a handful of laboratory studies encompassing a limited diversity of phytoplankton species. We therefore assessed Φe,C for a wide range of marine phytoplankton (n = 17 strains) spanning multiple taxonomic and size classes. Data mined from previous studies were further considered to determine whether Φe,C variability could be explained by taxonomy versus other phenotypic traits influencing growth and physiological performance (e.g., cell size). We found that Φe,C exhibited considerable variability (~4–10 mol e‐ · [mol C]−1) and was negatively correlated with growth rate (R2 = 0.7, P < 0.01). Diatoms exhibited a lower Φe,C compared to chlorophytes during steady‐state, nutrient‐replete growth. Inclusion of meta‐analysis data did not find significant relationships between Φe,C and class, or growth rate, although confounding factors inherent to methodological inconsistencies between studies likely contributed to this. Knowledge of empirical relationships between Φe,C and growth rate coupled with recent improvements in ...
Hurtado-McCormick, V, Kahlke, T, Petrou, K, Jeffries, T, Ralph, PJ & Seymour, JR 2021, 'Corrigendum: Regional and Microenvironmental Scale Characterization of the Zostera muelleri Seagrass Microbiome', Frontiers in Microbiology, vol. 12, p. 642964.
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[This corrects the article DOI: 10.3389/fmicb.2019.01011.].
Hurtado-McCormick, V, Krix, D, Tschitschko, B, Siboni, N, Ralph, PJ & Seymour, JR 2021, 'Shifts in the seagrass leaf microbiome associated with wasting disease in', Marine and Freshwater Research, vol. 72, no. 9, pp. 1303-1320.
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Seagrass wasting disease (SWD), an infection believed to be caused by Labyrinthula zosterae, has been linked to seagrass declines in several places around the world. However, there is uncertainty about the mechanisms of disease and the potential involvement of opportunistic colonising microorganisms. Using 16S rRNA gene amplicon sequencing, we compared the microbiome of SWD lesions in leaves of Zostera muelleri with communities in adjacent asymptomatic tissues and healthy leaves. The microbiome of healthy leaf tissues was dominated by Pseudomonas and Burkholderia, whereas the most predominant taxa within adjacent tissues were Pseudomonas and Rubidimonas. Members of the Saprospiraceae, potential macroalgal pathogens, were over-represented within SWD lesions. These pronounced changes in microbiome structure were also apparent when we examined the core microbiome of different tissue types. Although the core microbiome associated with healthy leaves included three operational taxonomic units (OTUs) classified as Burkholderia, Cryomorphaceae and the SAR11 clade, a single core OTU from the Arenicella was found within adjacent tissues. Burkholderia are diazotrophic microorganisms and may play an important role in seagrass nitrogen acquisition. In contrast, some members of the Arenicella have been implicated in necrotic disease in other benthic animals. Moreover, microbiome structure was maintained across sites within healthy tissues, but not within SWD lesions or the tissues immediately adjacent to lesions. Predicted functional profiles revealed increased photoautotrophic functions in SWD tissues relative to healthy leaves, but no increase in pathogenicity or virulence. Notably, we demonstrated the presence of L. zosterae in SWD lesions by polymerase chain reaction, but only in one of the two sampled locations, which indicates that other microbiological factors may be involved in the initiation or development of SWD-like symptoms. This study suggests t...
Ibrahim, I, Bhoopal, V, Seo, DH, Afsari, M, Shon, HK & Tijing, LD 2021, 'Biomass-based photothermal materials for interfacial solar steam generation: a review', Materials Today Energy, vol. 21, pp. 100716-100716.
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Ibrahim, I, Seo, DH, Angeloski, A, McDonagh, A, Shon, HK & Tijing, LD 2021, '3D microflowers CuS/Sn2S3 heterostructure for highly efficient solar steam generation and water purification', Solar Energy Materials and Solar Cells, vol. 232, pp. 111377-111377.
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Solar-driven interfacial steam generation is a promising method to produce potable water using renewable energy and help solve global clean water scarcity problems. However, the design of photothermal materials (PTMs) with excellent light absorption that can localize heat at the air/water interface, and facilitate water vapor generation remains a key challenge for its practical implementation. In this work, we demonstrate the synthesis of heterostructure microflowers composed of vertically aligned CuS/Sn2S3 nanosheets (3D CSS-NS MF) using a single-step solvothermal method for solar steam generation application. The microflower structures and the abundant nanocavities between the vertically aligned nanosheets resulted in significant sunlight harvesting over the solar spectrum, excellent heat localization through trapping and re-absorbing the heat, and fast escape of water vapor. Under 1 sun (1 kW m-2) illumination, a high water evaporation rate of 1.42 kg m-2 h-1, corresponding to an efficiency of 82.93% was obtained. The 3D CSS-NS MF based solar evaporator exhibited remarkable salt ions rejection efficiency and good reusability over 10 cycles. Furthermore, efficient removal of organic dyes was observed in application geared towards wastewater treatment with a rejection ∼99.9%. Our work demonstrates the potential of using novel semiconductor-based nanocomposites as effective photothermal materials for high-performance solar steam generation in water desalination and wastewater treatment applications.
Ibrahim, I, Seo, DH, McDonagh, AM, Shon, HK & Tijing, L 2021, 'Semiconductor photothermal materials enabling efficient solar steam generation toward desalination and wastewater treatment', Desalination, vol. 500, pp. 114853-114853.
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© 2020 Elsevier B.V. Water scarcity issues around the world have renewed interest in the use of solar water evaporation as a means of providing fresh water. Advances in photothermal materials and thermal management, together with new interfacial system designs, have considerably improved the overall efficiency of solar steam generation (SSG) for desalination and wastewater treatment. Several classes of rationally-designed photothermal materials (PTMs) and nanostructures have enabled effective absorption of broad solar spectrum resulting in improved solar evaporation efficiency. Among several classes of PTMs, semiconductor-based PTMs have demonstrated great potential for SSG. In this review, we highlight the progress and prospects in SSG with emphasis on the use and evolution of advanced semiconductor materials for PTMs and their various designs and engineered architectures. Applications and future prospects for desalination and wastewater treatment are also discussed.
Ibrar, I, Yadav, S, Ganbat, N, Samal, AK, Altaee, A, Zhou, JL & Nguyen, TV 2021, 'Feasibility of H2O2 cleaning for forward osmosis membrane treating landfill leachate', Journal of Environmental Management, vol. 294, pp. 113024-113024.
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Ideris, F, Shamsuddin, AH, Nomanbhay, S, Kusumo, F, Silitonga, AS, Ong, MY, Ong, HC & Mahlia, TMI 2021, 'Optimization of ultrasound-assisted oil extraction from Canarium odontophyllum kernel as a novel biodiesel feedstock', Journal of Cleaner Production, vol. 288, pp. 125563-125563.
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In this novel study, oil was extracted from the kernel of an exotic indigenous species known as Canarium odontophyllum via an ultrasound-assisted process. The extraction process was optimized using response surface methodology (RSM) based on the Box-Behnken experimental design (BBD). The optimal conditions for the investigated parameters were determined as ultrasound amplitude level: 38.30%, ratio of n-hexane to kernel powder: 50:1 in mL/g, extraction time: 45.79 min, resulting in an oil extraction yield of 63.48%. For verification purposes, experiments were conducted using the same optimized values of the investigated parameters which resulted in the average oil yield of 63.27% and this prove the reliability of the regression model. The extracted oil's fatty acid composition was obtained using a gas chromatograph (GC) equipped with flame-ionization detection (FID). The low acid value of the extracted oil is another interesting finding. This is important because it circumvents pretreatment processes such as degumming and esterification prior to the transesterification process. Biodiesel was produced from the oil via ultrasound-assisted transesterification, with a yield of 95.2%. Physiochemical properties of the C. odontophyllum biodiesel were determined, and it was found that all the tested properties comply with fuel specifications based on ASTM D6751 and EN 14214 standards. Significant savings of 52.3% and 80.9% in energy consumption and extraction time, respectively were achieved via ultrasound-assisted extraction compared with the conventional Soxhlet extraction. This study establishes the foundation and the need to further explore the usage of C. odontophyllum as a potential feedstock for biodiesel production.
Inayat, A, Shahbaz, M, Khan, Z, Inayat, M, Mofijur, M, Ahmed, SF, Ghenai, C & Ahmad, AA 2021, 'Heat integration modeling of hydrogen production from date seeds via steam gasification', International Journal of Hydrogen Energy, vol. 46, no. 59, pp. 30592-30605.
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The purpose of the current study is to identify the potential of energy-efficient hydrogen (H2) production from date seeds as biomass via steam gasification process along with heat integration in Gulf countries. A reaction kinetics model has been established for steam gasification with in-situ carbon dioxide (CO2) capture of date seeds using MATLAB software. The kinetics of reactions involved in the gasification process was calculated using the optimization parameters fitting approach. The heat integration model has been developed via mixed integer nonlinear programming (MINLP) in MATLAB. In the parametric study, temperature and steam/biomass ratio considered their impact on syngas composition and energy recovery. Results showed that both variables have a strong positive effect on H2 production and depicted maximum production of 68 mol% at a temperature of 750 °C with steam/biomass ratio of 1.2. Methane (CH4) and CO2 production were low in the product gas, which showed the activity of water gas shift reaction, methanation reaction, and carbonation reaction. Utilization of waste heat via process heat integration within the system reduced system's external heat load. More than 70% of energy recovered, which could be utilized for gasification and steam production. Energy analysis and process heat integration proved a prospective approach for energy-efficient and sustainable hydrogen production from date seeds.
Islam, A, Kalam, MA, Sayeed, MA, Shano, S, Rahman, MK, Islam, S, Ferdous, J, Choudhury, SD & Hassan, MM 2021, 'Escalating SARS-CoV-2 circulation in environment and tracking waste management in South Asia', Environmental Science and Pollution Research, vol. 28, no. 44, pp. 61951-61968.
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Iwasaki, K, Evenhuis, C, Tamburic, B, Kuzhiumparambil, U, O'Connor, W, Ralph, P & Szabó, M 2021, 'Improving light and CO2 availability to enhance the growth rate of the diatom, Chaetoceros muelleri', Algal Research, vol. 55, pp. 102234-102234.
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Diatoms (Bacillariophyceae) are an important source of feed for juvenile animals in aquaculture hatcheries. Increasing the yield of feed cultures by optimizing illumination and inorganic carbon supply could significantly reduce operational costs for hatcheries. In this study, the growth dynamics and photosynthetic efficiency of the aquaculture-relevant diatom Chaetoceros muelleri were monitored and modelled under four different light and CO2 conditions. By increasing the availability of both light and CO2, a growth rate of 1.59 ± 0.12 (day−1) was achieved for C. muelleri, an increase of approximately 89% compared to 0.84 ± 0.08 (day−1) which was recorded in cultures under light limitation with no CO2 addition. The real-time monitoring and modelling of growth dynamics and photosynthesis rates in different light and CO2 conditions have demonstrated that light availability can be improved by minimizing the path length of light through the culture, and the importance of on-demand CO2 supply. The techniques and results outlined in this study could be used to potentially improve biomass production in hatcheries.
Jahirul, MI, Rasul, MG, Brown, RJ, Senadeera, W, Hosen, MA, Haque, R, Saha, SC & Mahlia, TMI 2021, 'Investigation of correlation between chemical composition and properties of biodiesel using principal component analysis (PCA) and artificial neural network (ANN)', Renewable Energy, vol. 168, pp. 632-646.
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© 2020 Elsevier Ltd Biodiesel will provide a significant renewable energy source for transportation in the near future. In the present study, principal component analysis (PCA) has been used to understand the relationship between important properties of biodiesel and its chemical composition. Finally, several artificial intelligence-based models were developed to predict specific biodiesel properties based on their chemical composition. The experimental study was conducted in order to generate training data for the artificial neural network (ANN). Available (experimental) data from the literature was also employed for this modeling strategy. The analytical part of this study found a complex multi-dimensional correlation between chemical composition and biodiesel properties. Average numbers of double bonds in the chemical structure (representing the unsaturated component in biodiesel) and the poly-unsaturated component in biodiesel had a great impact on biodiesel properties. The simulation result in this study demonstrated that ANN is a useful tool for investigating the fuel properties from its chemical composition which eventually can replace the time consuming and costly experimental test.
Jamil, S, Loganathan, P, Kandasamy, J, Ratnaweera, H & Vigneswaran, S 2021, 'Comparing nanofiltration membranes effectiveness for inorganic and organic compounds removal from a wastewater-reclamation plant’s micro-filtered water', Materials Today: Proceedings, vol. 47, pp. 1389-1393.
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Jamil, S, Loganathan, P, Khan, SJ, McDonald, JA, Kandasamy, J & Vigneswaran, S 2021, 'Enhanced nanofiltration rejection of inorganic and organic compounds from a wastewater-reclamation plant’s micro-filtered water using adsorption pre-treatment', Separation and Purification Technology, vol. 260, pp. 118207-118207.
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© 2020 Elsevier B.V. Adsorption pre-treatment to enhance the nanofiltration (NF) removal of inorganic ions, dissolved organic carbon (DOC) and organic micropollutants (OMP) from microfiltered (MF) wastewater was investigated using NF 90 membrane (contact angle 79% and molecular weight cut off value of 90–200 Da). The NF showed greater rejection for divalent cations (Ca2+, Mg2+) and anions (SO42−) compared to monovalent cations (Na+, K+) and anions (Cl−, NO3−). The degree of total DOC removal was: GAC adsorption + NF (86%) > an ion exchange resin (Purolite) adsorption + NF (81%) > NF operation alone (72%). GAC + NF removed biopolymers and hydrophobic substances almost completely and the highest percentage of LMW neutral substances. In contrast, Purolite + NF almost completely removed humic substances. The degree of membrane fouling order was: LMW neutrals > building blocks > biopolymers > hydrophobics > humics. Adsorption pre-treatment reduced membrane fouling and increased solution flux, the outcome being better with GAC compared to Purolite. Of the 10 MOPs in the MF water, seven were rejected > 90% by NF without any pre-treatment. Conversely, Purolite and GAC pre-treatments rejected > 90% of all OMPs.
Jeffry, L, Ong, MY, Nomanbhay, S, Mofijur, M, Mubashir, M & Show, PL 2021, 'Greenhouse gases utilization: A review', Fuel, vol. 301, pp. 121017-121017.
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The excessive global emission of greenhouse gases (mainly carbon dioxide, CO2 and methane, CH4), especially due to the burning of fossil fuel for energy and power generation, is the main cause to the air pollution and greenhouse effect. This has eventually brought many issues, such as climate change and global warming, that will affect the standard life of human beings. Many strategies have been proposed to further reduce the excessive emission of greenhouse gases, including CO2 and CH4 utilization. This method not only reduce the CO2 concentration in the atmosphere, but also producing renewable energy (syngas) at the same time. Hence, CO2 and CH4 utilization is also a promising approach to assist in overcoming the energy crisis due to the increasing population in time. Basically, the utilization of CO2 and CH4 system can be categorized into four: (i) electrochemical reduction, (ii) advanced catalyst system, (iii) photocatalytic reduction, and (iv) plasma technology. In this review paper, the mechanism implemented on the four abovementioned categories and their respective limitations are presented. Besides, future recommendations to optimize the greenhouse gases utilization system for up-scaling purpose is also highlighted.
Jiang, J, Phuntsho, S, Pathak, N, Wang, Q, Cho, J & Shon, HK 2021, 'Critical flux on a submerged membrane bioreactor for nitrification of source separated urine', Process Safety and Environmental Protection, vol. 153, pp. 518-526.
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Membrane fouling is the biggest challenge in membrane based technology operation. Studies on critical flux mainly focused on membrane bioreactor for municipal wastewater and/or greywater treatment, which can significantly differ from the ultrafiltration membrane bioreactor (UF-MBRs) to treat source separated urine. In this work, the inhibitory factors on nitrifying bacteria activity were investigated for fast acclimation of nitrifying bacteria with high ammonium concentration and optimization of a high-rate partial nitrification MBR. The maximum nitrification rate of 447 ± 50 mgN L–1 d–1 was achieved when concentration of ammonia in feed urine is approximately 4006.3 ± 225.8 mg N L–1 by maintaining desired pH around 6.2 and FA concentrations below 0.5 mgL−1. Furthermore, for the first time, the impact of different operational and filtration conditions (i.e. aeration intensity, filtration method, imposed flux, intermittent relaxation, biomass concentration) on the reversibility of membrane fouling was carried out for enhancement of membrane flux and fouling mitigation. Fouling mechanisms for minor irreversible fouling observed under sub-critical condition were pore blocking and polarization. To mitigate membrane fouling, the UF module with effective membrane surface area of 0.02 m2 is recommended to be operated at the aeration intensity of 0.4 m3 h−1, intermittent relaxation of 15 min, biomass concentration of 3.5 g L−1.
Kalam, MA, Davis, TP, Islam, MA, Islam, S, Kittle, BL & Casas, MP 2021, 'Exploring behavioral determinants of handwashing with soap after defecation in an urban setting in Bangladesh: findings from a barrier analysis', Journal of Water, Sanitation and Hygiene for Development, vol. 11, no. 6, pp. 1006-1015.
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Abstract Social and behavior change (SBC) has long been recognized as a necessary step in the promotion of handwashing with soap (HHWS), and identifying the barriers and enablers of this behavior are key to increasing its adoption. Based on the health belief model (HBM), the theory of reasoned action (TRA) and other behavioral models, this barrier analysis study was conducted to identify the barriers and enablers of HWWS after defecation in an urban setting in Bangladesh. We conducted interviews with 45 adults who washed their hands with soap after defecation (doers) and compared them to 45 adults who did not (non-doers). The analysis showed that the main barriers of HWWS after defecation were related to perceived self-efficacy, difficulty to remember to buy soap, access to low-cost soap, low perceived severity of diarrhea, and not believing that HWWS would reduce diarrhea. Believing that it is Allah's will when one gets diarrhea was mentioned more frequently by the non-doers, while feeling clean and keeping free from illness were reported as benefits of HWWS significantly by the doers. The results suggest that an SBC strategy that addresses these key barriers and enablers would be more effective in promoting the adoption of HWWS.
Kaliaraj, GS, Vishwakarma, V, Dawn, SS, Karthik, A, Vigneshwaran, S & Naidu, GD 2021, 'Reduction of sulphate reducing bacterial survival by Cu-Ni, Zn-Ni and Cu-Zn-Ni coatings using electroless plating technique for oil/diesel pipeline applications', Materials Today: Proceedings, vol. 45, pp. 6804-6806.
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Kaw, HY, Jin, X, Liu, Y, Cai, L, Zhao, X, Wang, J, Zhou, JL, He, M & Li, D 2021, 'Gas-liquid microextraction coupled with magnetic-assisted dispersive solid-phase extraction clean-up for multi-residue pesticide analysis in fatty foods of animal origin', LWT, vol. 137, pp. 110448-110448.
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An effective sequential clean-up method by coupling gas-liquid microextraction (GLME) and magnetic-assisted dispersive solid phase extraction (d-SPE) termed as GLME-MA-d-SPE has been developed for multi-residue pesticide analysis in different fatty foods of animal origin. GLME is applied as a primary clean-up step to remove low-volatile interferences, followed by a secondary clean-up technique through adsorptive removal using d-SPE to eliminate other co-extracts like organic acids in fatty biological samples. As much as 99.3% of lipid substances were effectively eliminated by this powerful clean-up method, and the chromatographic analysis by GC-MS showed at least two orders of magnitude reduction for peaks of interference. Analytical results verified the accuracy and precision of this method with recoveries of 50 pesticides ranged from 60.5% to 119.7%, and RSDs of less than 20%. Permethrin was present in salmon, pork and egg samples, but the concentrations were within the maximum residue levels (MRLs) permitted by both national and international regulations. The GLME-MA-d-SPE technique minimizes matrix effects, and it exhibits significant potential as an analytical technique of food safety control systems for broad-spectrum screening trace-level environmental pollutants in complex biological matrices.
Khan, AUH, Liu, Y, Naidu, R, Fang, C, Dharmarajan, R & Shon, H 2021, 'Interactions between zinc oxide nanoparticles and hexabromocyclododecane in simulated waters', Environmental Technology & Innovation, vol. 24, pp. 102078-102078.
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The zinc oxide nanoparticles (ZnO-NPs) have been increasingly applied in industries and consumer products, causing release of these nanoparticles in environments. The behaviour of ZnO-NPs in the water systems is complicated due to the presence of different cations, anions, organic substances (e.g. humic acid HA) and other organic pollutants (e.g. commonly used brominated flame retardant, BFR). In particular, the aggregation and alteration of these nanoparticles can be influenced by co-existence contaminants. In this study, the interactions between hexabromocyclododecane (HBCD) and ZnO-NPs were investigated for the physicochemical properties and colloidal stability changes in various simulated waters. This is significant to understand the fate and behaviour of ZnO-NPs at environmental relevant conditions. The surface chemistry and particle size distribution (PSD) of ZnO-NPs with and without the existence of HBCD, HA and electrolytes (NaCl, CaCl2 and MgCl2) after different periods (1 and 3 weeks) were investigated at pH 7.00 ± 0.02. The size of the ZnO-NPs increased from nanometres to micrometres with the addition of numerous concentrations of HBCD, HA, and cations and their mixtures. The zeta potential of ZnO-NPs increased upon addition of HBCD, HA and electrolytes indicating a more stable agglomeration form while less agglomeration was observed in the ZnO-NPs and HA suspension after 3 weeks. Hydrophobic and electrostatic interactions, van der Waals forces, including hydrogen bonding and cation bridging could be potential interactive driving forces. The results indicated agglomeration of ZnO-NPs in the existence of organic substances, salts and contaminants, thus sedimentation and precipitation are promising under salty surface water/sea water.
Khan, HM, Iqbal, T, Mujtaba, MA, Soudagar, MEM, Veza, I & Fattah, IMR 2021, 'Microwave Assisted Biodiesel Production Using Heterogeneous Catalysts', Energies, vol. 14, no. 23, pp. 8135-8135.
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As a promising renewable fuel, biodiesel has gained worldwide attention to replace fossil-derived mineral diesel due to the threats concerning the depletion of fossil reserves and ecological constraints. Biodiesel production via transesterification involves using homogeneous, heterogeneous and enzymatic catalysts to speed up the reaction. The usage of heterogeneous catalysts over homogeneous catalysts are considered more advantageous and cost-effective. Therefore, several heterogeneous catalysts have been developed from variable sources to make the overall production process economical. After achieving optimum performance of these catalysts and chemical processes, the research has been directed in other perspectives, such as the application of non-conventional methods such as microwave, ultrasonic, plasma heating etc, aiming to enhance the efficiency of the overall process. This mini review is targeted to focus on the research carried out up to this date on microwave-supported heterogeneously catalysed biodiesel production. It discusses the phenomenon of microwave heating, synthesis techniques for heterogeneous catalysts, microwave mediated transesterification reaction using solid catalysts, special thermal effects of microwaves and parametric optimisation under microwave heating. The review shows that using microwave technology on the heterogeneously catalysed transesterification process greatly decreases reaction times (5–60 min) while maintaining or improving catalytic activity (>90%) when compared to traditional heating.
Khan, HM, Iqbal, T, Yasin, S, Irfan, M, Kazmi, M, Fayaz, H, Mujtaba, MA, Ali, CH, Kalam, MA, Soudagar, MEM & Ullah, N 2021, 'Production and utilization aspects of waste cooking oil based biodiesel in Pakistan', Alexandria Engineering Journal, vol. 60, no. 6, pp. 5831-5849.
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Excessive fuel demand thrusts the Pakistani government to import large volumes of fuel from foreign sources, creating adverse effects on the country's economy. Therefore, exploring an alternative to fossil fuels is unavoidable. The option of environmentally friendly fuel like biodiesel produced from indigenous waste is an additional bonus for the populous developing country like Pakistan where likelihood of waste generation is huge. There exists a potential option for sustainable biodiesel production utilizing excessive waste cooking oil available in the country which otherwise is an ecological burden. The present work is focused to sturdily vindicate the appropriateness of waste cooking oil-based biodiesel generation and utilization in Pakistan through SWOT-AHP, TOWS and PESTLE analysis. The prioritization of SWOT through AHP in view of experts’ perception displayed the strengths and opportunities in highest group priority values (Strengths: 0.51, Opportunities: 0.29). Furthermore, TOWS analysis suggests promising strategies for the sustainable implementation of commercial aspect of waste oil-based biodiesel in Pakistan. Political, Economic, Social, Technological, Legal and Environmental (PESTLE) analysis favors the strengths and opportunities factors of SWOT and TOWS strategies for the application of waste cooking oil based biodiesel in country. At the end, regional recommendations have been provided for the implementation of biodiesel production scenario in country.
Khan, T, Bari, G, Kang, H-J, Lee, T-G, Park, J-W, Hwang, H, Hossain, S, Mun, J, Suzuki, N, Fujishima, A, Kim, J-H, Shon, H & Jun, Y-S 2021, 'Synthesis of N-Doped TiO2 for Efficient Photocatalytic Degradation of Atmospheric NOx', Catalysts, vol. 11, no. 1, pp. 109-109.
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Titanium oxide (TiO2) is a potential photocatalyst for removing toxic NOx from the atmosphere. Its practical application is, however, significantly limited by its low absorption into visible light and a high degree of charge recombination. The overall photocatalytic activity of TiO2 remains too low since it can utilize only about 4–5% of solar energy. Nitrogen doping into the TiO2 lattice takes advantage of utilizing a wide range of solar radiation by increasing the absorption capability towards the visible light region. In this work, N-doped TiO2, referred to as TC, was synthesized by a simple co-precipitation of tri-thiocyanuric acid (TCA) with P25 followed by heat treatment at 550 degrees C. The resulting nitrogen doping increased the visible-light absorption and enhanced the separation/transfer of photo-excited charge carriers by capturing holes by reduced titanium ions. As a result, TC samples exhibited excellent photocatalytic activities of 59% and 51% in NO oxidation under UV and visible light irradiation, in which the optimum mass ratio of TCA to P25 was found to be 10.
Khanafer, D, Ibrahim, I, Yadav, S, Altaee, A, Hawari, A & Zhou, J 2021, 'Brine reject dilution with treated wastewater for indirect desalination', Journal of Cleaner Production, vol. 322, pp. 129129-129129.
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Khanafer, D, Yadav, S, Ganbat, N, Altaee, A, Zhou, J & Hawari, AH 2021, 'Performance of the Pressure Assisted Forward Osmosis-MSF Hybrid Desalination Plant', Water, vol. 13, no. 9, pp. 1245-1245.
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An osmotically driven membrane process was proposed for seawater pretreatment in a multi-stage flashing (MSF) thermal plant. Brine reject from the MSF plant was the draw solution (DS) in the forward osmosis (FO) process in order to reduce chemical use. The purpose of FO is the removal of divalent ions from seawater prior the thermal desalination. In this study, seawater at 80 g/L and 45 g/L concentrations were used as the brine reject and seawater, respectively. The temperature of the brine reject was 40 °C and of seawater was 25 °C. Commercial thin-film composite (TFC) and cellulose triacetate (CTA) membranes were evaluated for the pretreatment of seawater in the FO and the pressure-assisted FO (PAFO) processes. Experimental results showed 50% more permeation flux by increasing the feed pressure from 1 to 4 bar, and permeation flux reached 16.7 L/m2h in the PAFO process with a TFC membrane compared to 8.3 L/m2h in the PAFO process with CTA membrane. TFC membrane experienced up to 15% reduction in permeation flux after cleaning with DI water while permeation flux reduction in the CTA membrane was >6%. The maximum recovery rate was 11.5% and 8.8% in the PAFO process with TFC and CTA membrane, respectively. The maximum power consumption for the pretreatment of seawater was 0.06 kWh/m3 and 0.1 kWh/m3 for the PAFO process with a TFC and CTA membrane, respectively.
Khanh Nguyen, V, Kumar Chaudhary, D, Hari Dahal, R, Hoang Trinh, N, Kim, J, Chang, SW, Hong, Y, Duc La, D, Nguyen, XC, Hao Ngo, H, Chung, WJ & Nguyen, DD 2021, 'Review on pretreatment techniques to improve anaerobic digestion of sewage sludge', Fuel, vol. 285, pp. 119105-119105.
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Anaerobic digestion (AD) of sewage sludge is one of the most efficient, effective, and environmentally sustainable remediation techniques; however, the presence of complex floc structures, hard cell walls, and large amounts of molecular organic matter in the sludge hinder AD hydrolysis. Consequently, sewage sludge pretreatment is a prerequisite to accelerate hydrolysis and improve AD efficiency. This review focuses on pretreatment techniques for improving sewage sludge AD, which include mechanical, chemical, thermal, and biological processes. The various pretreatment process effects are discussed in terms of advantages and disadvantages, including their effectiveness, and recent achievements are reviewed for improved biogas production.
Kumar, A, Kim, Y, Su, X, Fukuda, H, Naidu, G, Du, F, Vigneswaran, S, Drioli, E, Hatton, TA & Lienhard, JH 2021, 'Advances and challenges in metal ion separation from water', Trends in Chemistry, vol. 3, no. 10, pp. 819-831.
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Technologies for selective metal ion separation from water and wastewater are currently attracting strong research interest as a pathway to greater sustainability. The chemistry of metal ion separation processes is critical for understanding the mechanisms of selectivity and making the technologies viable. This paper discusses current advances and challenges in metal ion separation technologies from chemical points of view and proposes how they should be approached in the future.
Kumar, A, Naidu, G, Fukuda, H, Du, F, Vigneswaran, S, Drioli, E & Lienhard, JH 2021, 'Metals Recovery from Seawater Desalination Brines: Technologies, Opportunities, and Challenges', ACS Sustainable Chemistry & Engineering, vol. 9, no. 23, pp. 7704-7712.
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The urgent need for environmental sustainability has increasingly prompted policy makers to emphasize resource recovery from desalination brine streams. Recent research on resource recovery from waste streams has shown rising momentum with near term viability for several new technologies. In this perspective, we focus on new opportunities for metal resource recovery from seawater desalination brine, while outlining associated sustainability challenges and opportunities. The potential of metals recovery is discussed.
Kundariya, N, Mohanty, SS, Varjani, S, Hao Ngo, H, W. C. Wong, J, Taherzadeh, MJ, Chang, J-S, Yong Ng, H, Kim, S-H & Bui, X-T 2021, 'A review on integrated approaches for municipal solid waste for environmental and economical relevance: Monitoring tools, technologies, and strategic innovations', Bioresource Technology, vol. 342, pp. 125982-125982.
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Rapid population growth, combined with increased industrialization, has exacerbated the issue of solid waste management. Poor management of municipal solid waste (MSW) not only has detrimental environmental consequences but also puts public health at risk and introduces several other socioeconomic problems. Many developing countries are grappling with the problem of safe disposing of large amounts of produced municipal solid waste. Unmanaged municipal solid waste pollutes the environment, so its use as a potential renewable energy source would aid in meeting both increased energy needs and waste management. This review investigates emerging strategies and monitoring tools for municipal solid waste management. Waste monitoring using high-end technologies and energy recovery from MSW has been discussed. It comprehensively covers environmental and economic relevance of waste management technologies based on innovations achieved through the integration of approaches.
Labeeuw, L, Commault, AS, Kuzhiumparambil, U, Emmerton, B, Nguyen, LN, Nghiem, LD & Ralph, PJ 2021, 'A comprehensive analysis of an effective flocculation method for high quality microalgal biomass harvesting', Science of The Total Environment, vol. 752, pp. 141708-141708.
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Laiolo, L, Matear, R, Soja-Woźniak, M, Suggett, DJ, Hughes, DJ, Baird, ME & Doblin, MA 2021, 'Modelling the impact of phytoplankton cell size and abundance on inherent optical properties (IOPs) and a remotely sensed chlorophyll-a product', Journal of Marine Systems, vol. 213, pp. 103460-103460.
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© 2020 Elsevier B.V. Ocean colour data are commonly used to quantify primary production, study phytoplankton dynamics and calibrate marine models, thus understanding the origin of errors in the retrieved chlorophyll-a (Chl-a) product is critical. One source of uncertainty in retrieved Chl-a products can be related to large photosynthetic cells, characterised by lower mass-specific absorption coefficients due to increased packaging effect. Here, we explore the relationship between phytoplankton size structure and an ocean colour product using optical simulations and in situ observations. Specifically, we use an optical model to explore how phytoplankton cell size and abundance influence phytoplankton absorption and backscattering coefficients and the implication this has for water leaving radiance and the estimated Chl-a derived from satellite ocean colour. The optical model simulations show phytoplankton cell size has a significant impact on the remote-sensing reflectance, with Chl-a packaged in 5 to 10 μm cells resulting in about 54 to 76% the simulated ocean colour Chl-a compared to 1 μm cells, as determined by an algorithm that converts reflectances to Chl-a. To support optical simulations, size-fractionated Chl-a samples were collected from several water masses to investigate the phytoplankton size contribution (i.e., < 2 μm, 2–10 μm and > 10 μm) to the total Chl-a. We focused on the offshore eastern Australian ocean region, largely characterised by oligotrophic waters in which phytoplankton dominate the optical properties of the water column. Of the 22 stations sampled, a total of ten in situ size fractionated Chl-a measurements were matched-up with the corresponding clear-sky satellite Chl-a product. The matched-up points revealed a systematic underestimation of in situ Chl-a. With the low amount of data, it was not possible to statistically relate the satellite underestimation to a specific phytoplankton size class, but the observations showed th...
Leal, E, de Beyer, L, O'Connor, W, Dove, M, Ralph, PJ & Pernice, M 2021, 'Production optimisation of Tisochrysis lutea as a live feed for juvenile Sydney rock oysters, Saccostrea glomerata, using large-scale photobioreactors', Aquaculture, vol. 533, pp. 736077-736077.
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© 2020 Elsevier B.V. The aquaculture industry uses microalgae as a live feed for juvenile oysters in hatcheries to meet their nutritional requirements, including their need for several essential Poly Unsaturated Fatty Acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The mass culture of microalgae is not only a major bottleneck for the production of juvenile oysters, but also a significant cost, accounting for 20–50% of hatchery operating costs. Currently, low biomass concentrations, high production costs and poor cultivation systems limit the quantity and quality of microalgae feed. This study focused on Tisochrysis lutea, a microalgae species commonly used in aquaculture, and we assessed the potential of photobioreactors with an improved light source and CO2 input to increase biomass production and improve biochemical composition of algal feed. Two photobioreactor systems were compared: the current industry set up (DPI) comprising fluorescent lighting and minimal CO2 input versus an optimized system utilising LEDs and increased CO2. Cultures of T. lutea were monitored over a 12-day growth period and harvested on day 14 for biochemical analysis. Final cell density was significantly higher in the optimized system relative to the conventional culture systems (6.2 × 106 cells / mL versus 3.7 × 106 cells / mL, respectively). The biochemical profile of T. lutea was not significantly different between the two photobioreactors systems. The algal biomass produced during this comparative experiment was used in a feeding trial on oyster spat, Saccostrea glomerata. Spat fed with algae produced in optimized vs conventional photobioreactors showed no significant difference in growth, but oyster spat fed with T. lutea grown in optimized photobioreactors did show a significant increase in their EPA content. Overall, our results contribute to our understanding of how altered culture conditions affect microalgal production and biochemical composit...
Li, X, Guan, R, Ou, K, Fu, Q, Yang, G & Sun, Y 2021, 'Ultra-high stability and magnetic response of magnetorheological fluids based on magnetic ionic liquids and carbonyl iron fibers', Journal of Rheology, vol. 65, no. 6, pp. 1347-1359.
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Li, X, Kulandaivelu, J, Zhang, S, Shi, J, Sivakumar, M, Mueller, J, Luby, S, Ahmed, W, Coin, L & Jiang, G 2021, 'Data-driven estimation of COVID-19 community prevalence through wastewater-based epidemiology', Science of The Total Environment, vol. 789, pp. 147947-147947.
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Wastewater-based epidemiology (WBE) has been regarded as a potential tool for the prevalence estimation of coronavirus disease 2019 (COVID-19) in the community. However, the application of the conventional back-estimation approach is currently limited due to the methodological challenges and various uncertainties. This study systematically performed meta-analysis for WBE datasets and investigated the use of data-driven models for the COVID-19 community prevalence in lieu of the conventional WBE back-estimation approach. Three different data-driven models, i.e. multiple linear regression (MLR), artificial neural network (ANN), and adaptive neuro fuzzy inference system (ANFIS) were applied to the multi-national WBE dataset. To evaluate the robustness of these models, predictions for sixteen scenarios with partial inputs were compared against the actual prevalence reports from clinical testing. The performance of models was further validated using unseen data (data sets not included for establishing the model) from different stages of the COVID-19 outbreak. Generally, ANN and ANFIS models showed better accuracy and robustness over MLR models. Air and wastewater temperature played a critical role in the prevalence estimation by data-driven models, especially MLR models. With unseen datasets, ANN model reasonably estimated the prevalence of COVID-19 (cumulative cases) at the initial phase and forecasted the upcoming new cases in 2-4 days at the post-peak phase of the COVID-19 outbreak. This study provided essential information about the feasibility and accuracy of data-driven estimation of COVID-19 prevalence through the WBE approach.
Li, X, Li, M, Mei, Q, Niu, S, Wang, X, Xu, H, Dong, B, Dai, X & Zhou, JL 2021, 'Aging microplastics in wastewater pipeline networks and treatment processes: Physicochemical characteristics and Cd adsorption', Science of The Total Environment, vol. 797, pp. 148940-148940.
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Despite a wealth of information on removal of the microplastics (MPs) in wastewater treatment plants (WWTPs), little attention has been paid to how wastewater treatment process affect the MP physicochemical and adsorption characteristics. In this study, changes in physicochemical property of three MPs, i.e. polyamide (PA), polyethylene (PE) and polystyrene (PS) through the wastewater pipeline, grit and biological aeration tanks were investigated. The results show that compared with virgin MPs, the treated MPs have higher specific surface area and O content, and lower C and H contents, and glass transition temperature, implying that the three treatments cause the chain scission and oxidation of the MPs. Cd adsorption capacities of the MPs are higher than the corresponding virgin MPs after sulfidation in the pipeline (SWPN) and biological treatment in aeration tank (BTAT). Pearson correlation analysis shows that the increase is mainly resulted from the enhancement of the O-containing groups on the MPs. However, Cd adsorption capacities of the MPs decrease after mechanical abrasion in grit tank (MAGT), corresponding to the decrease in carbonyl index. Two dimensional FTIR correlation spectroscopy demonstrates that the NH bond in the PA plays a more important role than CH bond in the adsorption of Cd, but only change of the CH bond is found in the PE and PS. The findings provide new insights into the effect of WWTPs on the MP aging and physicochemical characteristics.
Li, X, Zhang, J, Shen, L, Qin, L, Fu, Q, Sun, Y & Liu, Y 2021, 'Magnetoresistive micro-displacement sensor based on magnetorheological fluid', Smart Materials and Structures, vol. 30, no. 4, pp. 045025-045025.
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Abstract A novel magnetoresistance material based on magnetorheological fluid (MRF) was developed for applications in micro-displacement sensor. The MRF samples were fabricated by dispersing carbonyl iron particles (CIP) into a magnetic ion liquid (MIL) composed of 1-methylethyl ether-3-butylimidazole cation and [Fe2Cl7]− anions. The magnetoresistance characteristics were also systematically tested. It was found that the resistance value of MRF with a CIP content of 20 vol% decreased from 125 to 24.4 KΩ when increasing the magnetic field from 0 to 0.2 T. A sensor device was developed to study the displacement sensing characteristics of MRF, and found that the sensor had a high sensitivity of 0.1 Ω μm−1 and a high resolution of 10.0 μm. The excellent performance can be attributed to the low modulus and good stability of the MIL matrix, allowing for easy change of the resistance by controlling the magnetic field or displacement. In summary, these unique characters make the present MRF a promising magnetoresistance material with potential applications in displacement sensor.
Li, X, Zhang, S, Shi, J, Luby, SP & Jiang, G 2021, 'Uncertainties in estimating SARS-CoV-2 prevalence by wastewater-based epidemiology', Chemical Engineering Journal, vol. 415, pp. 129039-129039.
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Wastewater-based epidemiology (WBE) is a promising approach for estimating population-wide COVID-19 prevalence through detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in wastewater. However, various methodological challenges associated with WBE would affect the accuracy of prevalence estimation. To date, the overall uncertainty of WBE and the impact of each step on the prevalence estimation are largely unknown. This study divided the WBE approach into five steps (i.e., virus shedding; in-sewer transportation; sampling and storage; analysis of SARS-CoV-2 RNA concentration in wastewater; back-estimation) and further summarized and quantified the uncertainties associated with each step through a systematic review. Although the shedding of SARS-CoV-2 RNA varied greatly between COVID-19 positive patients, with more than 10 infected persons in the catchment area, the uncertainty caused by the excretion rate became limited for the prevalence estimation. Using a high-frequency flow-proportional sampling and estimating the prevalence through actual water usage data significantly reduced the overall uncertainties to around 20-40% (relative standard deviation, RSD). And under such a scenario, the analytical uncertainty of SARS-CoV-2 RNA in wastewater was the dominant factor. This highlights the importance of using surrogate viruses as internal or external standards during the wastewater analysis, and the need for further improvement on analytical approaches to minimize the analytical uncertainty. This study supports the application of WBE as a complementary surveillance strategy for monitoring COVID-19 prevalence and provides methodological improvements and suggestions to enhance the reliability for future studies.
Li, Y, Huang, C, Ngo, HH, Yin, S, Dong, Z, Zhang, Y, Chen, Y, Lu, Y & Guo, W 2021, 'Analysis of event stratigraphy and hydrological reconstruction of low-frequency flooding: A case study on the Fenhe River, China', Journal of Hydrology, vol. 603, pp. 127083-127083.
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Li, Y, Wang, D, Yang, G, Yuan, X, Li, H, Wang, Q, Ni, B, He, D, Fu, Q, Jiang, L, Tang, W, Yang, F & Chen, H 2021, 'Comprehensive investigation into in-situ chemical oxidation of ferrous iron/sodium percarbonate (Fe(II)/SPC) processing dredged sediments for positive feedback of solid–liquid separation', Chemical Engineering Journal, vol. 425, pp. 130467-130467.
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Before disposal of dredged sediments (DS), filtrating DS is commonly used for their volume reduction. The work, for the first time, investigated Fe(II)/SPC processing DS to advance their solid–liquid separation from filtering feasibility, operational mechanism, technic reinforcement to potential implication. 16 mg Fe(II)/TSS & 60 mg SPC/TSS treatment elevated solid content of DS from 25.7% to 55.7% (vacuum filtration for 10 min), along with filtrate volume increased from 45.0 mL to 77.5 mL. •OH and Fe(III) with their hydrolyzed polymers, from Fe(II)/SPC system, are mainly lying behind the improved solid–liquid separation. Detailedly, the dilapidation of extracellular polymeric substances (EPS) with the destruction of biomolecules in EPS was completed by •OH invasion, which might rearrange the extracellular/intracellular protein configuration, with the increments of β-sheet & random coil but the decrement of α-helices. Simultaneously, Fe(III) and their hydrolyzed polymers promoted the relief of electrostatic repulsive-forces and the squeezing of double-electric layers, and the gathered DS could be held by integration of Fe(III) with –COOH and –OH. Additionally, CaO strengthened the filtering velocity/extent of Fe(II)/SPC-treated DS. After 70 mg/g CaO treatment, its solid content further elevated to 61.7% after vacuum filtration for 5.5 min, mainly resulting from skeleton construction by CaO, charge neutrality by released Ca2+, bridging cell debris and biopolymers by released Ca2+, compression of colloids double layers by released Ca2+, and binding PO43- in outer centrate liquid by released Ca2+.
Li, Y, Wang, D, Yang, G, Yuan, X, Yuan, L, Li, Z, Xu, Q, Liu, X, Yang, Q, Tang, W, Jiang, L, Li, H, Wang, Q & Ni, B 2021, 'In-depth research on percarbonate expediting zero-valent iron corrosion for conditioning anaerobically digested sludge', Journal of Hazardous Materials, vol. 419, pp. 126389-126389.
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Anaerobically digested sludge (ADS) is commonly hard to dewater for the presence of extracellular polymeric substances (EPS) and the liberation of glutinous soluble microbic products during anaerobic digestion. Sodium percarbonate (SPC) expediting zero-valent iron (ZVI) corrosion (SPC/ZVI) process firstly conditioned ADS to amend its dewaterability. Results showed that SPC/ZVI conditioning decreased moisture content of dewatered cake from 90.5% (control) to 69.9% with addition of 0.10 g/g TS SPC and 0.20 g/g TS ZVI. Mechanistic research indicated that the enhanced ADS dewaterability mainly resulted from •OH and Fe(III)/iron polymers yielded in SPC/ZVI. •OH disrupted EPS, damaged cytoderm & cytomembrane, and lysed intracellular substances, unbinding the bound water. Meanwhile, the breakage and inactivation of microbe by •OH prompted the production of macro-pores in ADS. •OH adjusted the conformation of extracellular/intracellular proteins by intervening in the H-bonds and S-S bonds, availing the hydrophobicity and slight flocculation of ADS. •OH further facilitated the despiralization of α-helical to β-sheet structure in ADS pellets, benefiting cell-to-cell aggregation. Additionally, Fe(III)/iron polymers from ZVI corrosion accelerated to gather ADS and maintained its floc structure. Consequently, SPC/ZVI conditioning not only adjusted the natures of ADS and its EPS but also the features of residual pellets, which further induced the advancement of ADS dewaterability. In addition, SPC/ZVI conditioning possibly surmounts some limitations existing in ZVI/Peroxide or ZVI/Persulfate technique.
Li, Y, Zeng, X, Zhou, J, Shi, Y, Umar, HA, Long, G & Xie, Y 2021, 'Development of an eco-friendly ultra-high performance concrete based on waste basalt powder for Sichuan-Tibet Railway', Journal of Cleaner Production, vol. 312, pp. 127775-127775.
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Generally, tunnel waste is stacked in the slag field nearby for landfilling, which is harmful to sustainable development. The broken rocks and rock powder among the tunnel waste can be recycled to produce machine-made sand, producing many by-products calling rock powder. Based on the practical project, three types of waste basalt powder (BP), from tunnel excavation waste and by-products (rock powder) of machine-made sand producing from tunnel excavation waste in Sichuan-Tibet railway construction sites, was used to prepare an eco-friendly UHPC. The BP is used to replace the cement and is included in the design UHPC based on Modified Andreasen &Andersen particle packing model (MAA). Moreover, the chemical and physical behaviors and ecological evaluation of the designed UHPC and UHPC pasted were discussed. The results showed that when BP (Specific surface area 4.6582 m2/g) replaces up to 15%, the highest compressive strength of designed UHPC (220 MPa) was obtained. Compared with quartz powder, the pozzolanic activity of BP was generally low and increased with the increase of reaction temperature. However, the presence of BP and its fineness in UHPC pastes increased the values of the total autogenous shrinkage and decreased the total heat release at an early age of designed UHPC pastes, this effect is more pronounced with temperature increasing. Based on a quartering method with embodied carbon dioxide emissions and the compressive strength, UHPC with waste BP reduced embodied carbon dioxide and possessed higher compressive strength and lower environmental impact than the control samples of UHPC.
Liu, F, Han, R, Naficy, S, Casillas, G, Sun, X & Huang, Z 2021, 'Few-Layered Boron Nitride Nanosheets for Strengthening Polyurethane Hydrogels', ACS Applied Nano Materials, vol. 4, no. 8, pp. 7988-7994.
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Two-dimensional hexagonal boron nitride nanosheets (BNNS) are an outstanding filler and additive, since they are transparent, thermally stable, and chemically inert. However, it is difficult to obtain few-layered BNNS with large lateral sizes in an efficient way due to the strong interlayer interactions in h-BN. Herein, a facile and efficient molten salt-assisted synthesis has been developed to prepare few-layered BNNS with a few microns in lateral size. Ammonia borane was mixed with KCl and NaCl and then heated to 1000 °C and held for 2 min, and the resultant powders were sonicated in water to produce hydroxylated BNNS. Used as an additive with 0.066 wt % loading, the functionalized BNNS can effectively improve the mechanical modulus of polyurethane (PU) hydrogels from 1635 to 2776 kPa, and the optical property of the hydrogel is not compromised. The BNNS-reinforced PU hydrogel with significantly improved mechanical properties can be highly useful in the application of printed electronics.
Liu, F, Han, R, Nattestad, A, Sun, X & Huang, Z 2021, 'Carbon- and oxygen-doped hexagonal boron nitride for degradation of organic pollutants', Surface Innovations, vol. 9, no. 4, pp. 222-230.
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Carbon- and oxygen-doped hexagonal boron nitrides (BCNOs) with good chemical stability and photoresponsiveness to visible light are found to be promising metal-free catalysts for degradation of Rhodamine B (RhB). By doping with heteroatoms of carbon and oxygen, insulating hexagonal boron nitride was transformed into semiconducting BCNO. The BCNO photocatalyst presents photodegradation performance towards RhB, with degradation rates up to 1.39 h−1 (0.05 wt% catalyst loading). The active species involved in the photoreaction were demonstrated to be superoxide anion radical (˙O2 −) and holes (h+), as opposed to ˙OH in the most studied titanium dioxide. The stability of BCNO in highly acidic environments was exploited for catalyst regeneration, as is necessary after long-term use and poisoning. This work demonstrates that BCNO is a promising low-cost and metal-free photocatalyst for environmental pollution remediation.
Liu, H, Li, X, Zhang, Z, Nghiem, LD, Gao, L & Wang, Q 2021, 'Semi-continuous anaerobic digestion of secondary sludge with free ammonia pretreatment: Focusing on volatile solids destruction, dewaterability, pathogen removal and its implications', Water Research, vol. 202, pp. 117481-117481.
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Our previous work has reported the pretreatment of secondary sludge with free ammonia (NH3, FA) enhanced the methane production in batch biochemical methane potential tests. However, the batch biochemical methane potential test could only provide conservative results compared to continuous/semi-continuous anaerobic digestion. Also, the impacts of FA pretreatment on the key anaerobic digestion parameters, including volatile solids (VS) destruction, sludge dewaterability and pathogen removal, are still unknown. This study for the first time investigated these impacts using semi-continuous anaerobic digestion systems for 130 days. Pretreatment of secondary sludge for 24 h at an FA concentration of 560 mg NH3-N/L improved VS destruction by 26.4% (from 22.0 to 27.8%), supported by a similar increase of 28.6% in methane production (from 126.7 to 162.9 ml CH4/g VSfed). Model based analysis revealed that FA pretreatment improved the sludge degradability extent, which may be the reason for the enhanced VS destruction. Equally importantly, the dewaterability of the digested sludge with FA pretreatment was also enhanced by 9.2% (from 12.0 to 13.1% in solids content of the dewatered digested sludge), which could be partly attributed to the increased zeta potential from -16.7 to -14.5 mV. Anaerobic digestion with FA pretreatment enhanced the removals of Fecal Coliform and E. Coli by 1.3 and 1.4 log MPN/g TS (MPN: Most Probable Number; TS: Total Solids), indicating FA pretreatment was effective in enhancing pathogen removal. With inorganic solids representing 21% of the sludge used, the volume of dewatered sludge to be disposed of was reduced by 14.5% via FA pretreatment. This will substantially decrease the cost as evaluated by economic analysis. In brief, this study provides a promising strategy to enhance sludge reduction in anaerobic digestion and is of great significance in promoting the application of FA pretreatment strategy in the real world.
Liu, H, Wang, Z, Nghiem, LD, Gao, L, Zamyadi, A, Zhang, Z, Sun, J & Wang, Q 2021, 'Solid-Embedded Microplastics from Sewage Sludge to Agricultural Soils: Detection, Occurrence, and Impacts', ACS ES&T Water, vol. 1, no. 6, pp. 1322-1333.
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Liu, M, Xie, K, Nothling, MD, Zu, L, Zhao, S, Harvie, DJE, Fu, Q, Webley, PA & Qiao, GG 2021, 'Ultrapermeable Composite Membranes Enhanced Via Doping with Amorphous MOF Nanosheets', ACS Central Science, vol. 7, no. 4, pp. 671-680.
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Thin-film composite (TFC) polymeric membranes have attracted increasing interest to meet the demands of industrial gas separation. However, the development of high-performance TFC membranes within their current configuration faces two key challenges: (i) the thickness-dependent gas permeability of polymeric materials (mainly poly(dimethylsiloxane) (PDMS)) and (ii) the geometric restriction effect due to the limited pore accessibility of the underlying porous substrate. Here we demonstrate that the incorporation of trace amounts (∼1.8 wt %) of amorphous metal-organic framework (MOF) nanosheets into the gutter layer of TFC assemblies can simultaneously address these two limitations by the creation of rapid, transmembrane gas diffusion pathways. The resultant PDMS&MOF membrane displayed excellent CO2 permeance of 10450 GPU and CO2/N2 selectivity of 9.1. Leveraging this strategy, we successfully fabricate a novel TFC membrane, consisting of a PDMS&MOF gutter and an ultrathin (∼54 nm) poly(ethylene glycol) top selective layer via surface-initiated atom transfer radical polymerization. The complete TFC membrane exhibits excellent processability and remarkable CO2/N2 separation performance (1990 GPU with a CO2/N2 ideal selectivity of 39). This study reveals a strategy for the design and fabrication of a new TFC membrane system with unprecedented gas-separation performance.
Liu, X, Chen, Z, Tian, K, Zhu, F, Hao, D, Cheng, D, Wei, W, Zhang, L & Ni, B-J 2021, 'Fe3+ Promoted the Photocatalytic Defluorination of Perfluorooctanoic Acid (PFOA) over In2O3', ACS ES&T Water, vol. 1, no. 11, pp. 2431-2439.
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Liu, X, Fu, Q, Liu, Z, Zeng, T, Du, M, He, D, Lu, Q, Ni, B-J & Wang, D 2021, 'Alkaline pre-fermentation for anaerobic digestion of polyacrylamide flocculated sludge: Simultaneously enhancing methane production and polyacrylamide degradation', Chemical Engineering Journal, vol. 425, pp. 131407-131407.
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The residual Polyacrylamide (PAM) in sewage sludge might cause severe disturbance in anaerobic digestion, and appropriate solutions to alleviate such situation are urgently required. In present study, alkaline pre-fermentation was proposed for PAM-flocculated sewage sludge (PFS) pretreatment, by which both PFS methane production and PAM degradation were remarkably enhanced. Under the optimal alkaline pre-fermentation condition (pH 10 for 12 d), the biochemical methane potential of PFS (12 g PAM/kg TS) increased from 107.2 to 246.6 mL/g VS, the hydrolysis rate increased from 0.109 to 0.197 d−1, and the degradation efficiency of PAM increased from 30.6% to 80.1%. Mechanism analysis indicated that the alkaline pre-fermentation broke the large “PAM-sludge” floccules, decreased the molecular weight of PAM, which alleviated the disturbance situation of PAM-present digester and made PAM more available for microbes to be biodegraded. Moreover, PFS hydrolysis and acidification were simultaneously accelerated by alkaline pre-fermentation, thereby providing more bioavailable carbon substrates for subsequent methane producing and PAM co-metabolism. Microbial community analysis demonstrated syntrophic bacteria such as Petrimonas and Sedimentibacter, which had ability to degrade an extensive range of various types of organics including carbohydrates and PAM, were enriched in alkaline pre-fermenter, and the acetotrophic methanogen Methanosaeta, were elevated in anaerobic digester. This work provides an effective microbial based strategy to improve the efficiency of anaerobic digestion of PFS.
Liu, X, Ren, Z, Ngo, HH, He, X, Desmond, P & Ding, A 2021, 'Membrane technology for rainwater treatment and reuse: A mini review', Water Cycle, vol. 2, pp. 51-63.
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Because of the current situation of global water shortage, finding strategies that can effectively guarantee water safety and sustainable use has become an urgent problem that needs to be solved at present. Rainwater is a type of clean energy and the method of the treatment and reuse of rainwater has become a pivotal problem that is worthy of consideration. Membrane technology has become the preferred method in the field of wastewater treatment due to its small footprint, good treatment effect, and low cost, and has also received increasing attention in rainwater treatment field. This review aims to retrospect the existing research technology of rainwater treatment with membrane technology and seek out the most critical research gaps to meet future research needs and technological exploration. The characteristics of different types of membrane technologies in rainwater treatment were summarized, the water quality after treatment and the feasibility in practical applications was analyzed. Membrane fouling has been identified as the main challenge. Nowadays, the research on membrane surface modification and membrane process optimization is gradually deepening, and the exploration and synthesis of new membrane materials and the process of treating rainwater with various technology combinations are still under research. The future application prospects are worth looking forward to.
Liu, X, Wu, Y, Xu, Q, Du, M, Wang, D, Yang, Q, Yang, G, Chen, H, Zeng, T, Liu, Y, Wang, Q & Ni, B-J 2021, 'Mechanistic insights into the effect of poly ferric sulfate on anaerobic digestion of waste activated sludge', Water Research, vol. 189, pp. 116645-116645.
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Poly ferric sulfate (PFS), one of the typical inorganic flocculants widely used in wastewater management and waste activated sludge (WAS) dewatering, could be accumulated in WAS and inevitably entered in anaerobic digestion system at high levels. However, knowledge about its impact on methane production is virtually absent. This study therefore aims to fill this gap and provide insights into the mechanisms involved through both batch and long-term tests using either real WAS or synthetic wastewaters as the digestion substrates. Experimental results showed that the maximum methane potential and production rate of WAS was respectively retarded by 39.0% and 66.4%, whereas the lag phase was extended by 237.0% at PFS of 40 g per kg of total solids. Mechanism explorations exhibited that PFS induced the physical enmeshment and disrupted the enzyme activity involved in anaerobic digestion, resulting in an inhibitory state of the bioprocess of hydrolysis, acidogenesis, and methanogenesis. Furthermore, PFS's inhibition to hydrogenotrophic methanogenesis was much severer than that to acetotrophic methanogenesis, which could be supported by the elevated abundances of Methanosaeta sp and the dropped abundances of Methanobacterium sp in PFS-present digester, and probably due to the severe mass transfer resistance of hydrogen between the syntrophic bacteria and methanogens, as well as the higher hydrogen appetency of PFS-induced sulfate reducing bacteria. Among the derivatives of PFS, 'multinucleate and multichain-hydroxyl polymers' and sulfate were unveiled to be the major contributors to the decreased methane potential, while the 'multinucleate and multichain-hydroxyl polymers' were identified to be the chief buster to the slowed methane-producing rate and the extended lag time.
Liu, X, Xu, B, Duan, X, Hao, Q, Wei, W, Wang, S & Ni, B-J 2021, 'Facile preparation of hydrophilic In2O3 nanospheres and rods with improved performances for photocatalytic degradation of PFOA', Environmental Science: Nano, vol. 8, no. 4, pp. 1010-1018.
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This study used metal–organic-framework (MOF) derived In2O3 for the photocatalytic degradation of PFOA for the first time. MOF derived In2O3 demonstrated significantly enhanced performance for PFOA decomposition compared to commercial In2O3.
Liu, Y, Ma, C, Zhang, X, Ngo, HH, Guo, W, Zhang, M & Zhang, D 2021, 'Role of structural characteristics of MoS2 nanosheets on Pb2＋ removal in aqueous solution', Environmental Technology & Innovation, vol. 22, pp. 101385-101385.
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In this study, ultrasonic-assisted liquid-phase stripping and hydrothermal synthesis were used to prepare the two structural types of MoS2 nanosheets, namely u-MoS2 and h-MoS2, respectively. The u-MoS2 and h-MoS2 were characterized by various techniques, and the profound relationship between the structure and preparation method was also identified. Results indicated that adsorptions of Pb2＋ onto both u-MoS2 and h-MoS2 nanosheets reached equilibrium after 30 min at higher rates. The removal efficiencies of Pb2＋ by h-MoS2 and u-MoS2 nanosheets were 98.4% and 20.6% under the condition of low dosage (60 mg/L). The Pb2＋ by h-MoS2 adsorption fitted well to the Langmuir adsorption isotherm with the adsorption capacity of 174.0 mg/g while the Pb2＋ adsorption by u-MoS2 fitted well to the Freundlich isotherm (n=1). The obvious discrepancy suggested that the adsorption performance was directly associated with their structural properties, which were induced by two different synthesis methods. Based on these results, the effects of operational parameters (pH, dosage and existing ions) on Pb2＋ adsorption using h-MoS2 were further investigated. The dosage greatly affected the adsorption capacity and removal efficiency, while pH and coexisting ions had small effects on adsorption performance. In short, this study could help to better understand the role of MoS2 nanosheets’ structures obtained by different preparation methods for adsorption of heavy metal ions in aqueous solution.
Ma, M, Liu, Y, Wei, Y, Hao, D, Wei, W & Ni, B-J 2021, 'A facile oxygen vacancy and bandgap control of Bi(OH)SO4·H2O for achieving enhanced photocatalytic remediation', Journal of Environmental Management, vol. 294, pp. 113046-113046.
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The development of highly efficient photocatalysts is crucial for the remediation of organic pollutants. Herein, we reported a facile synthesis of oxygen vacancy rich Bi(OH)SO4·H2O photocatalyst by the control of precursor. The samples were characterized by XRD, scanning electron microscope, electron paramagnetic resonance, X-ray photoelectron spectroscopy etc. With more oxygen vacancies introduced, the photocatalytic activity on the degradation of RhB and tetracycline was significantly boosted. Density functional theory calculation was used to further reveal the influence of oxygen vacancy on the band structure of Bi(OH)SO4·H2O. The results and finding of this work are helpful for the development of sustainable environmental protection.
Mahlia, TMI & Fattah, IMR 2021, 'Energy for Sustainable Future', Energies, vol. 14, no. 23, pp. 7962-7962.
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Energy and the environment are interrelated, and they are critical factors that influence the development of societies [...]
Mahmudul, HM, Rasul, MG, Akbar, D, Narayanan, R & Mofijur, M 2021, 'A comprehensive review of the recent development and challenges of a solar-assisted biodigester system', Science of The Total Environment, vol. 753, pp. 141920-141920.
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The extensive use of fossil fuels and the environmental effect of their combustion products have attracted researchers to look into renewable energy sources. In addition, global mass production of waste has motivated communities to recycle and reuse the waste in a sustainable way to lower landfill waste and associated problems. The development of waste to energy (WtE) technology including the production of bioenergy, e.g. biogas produced from various waste through Anaerobic Digestion (AD), is considered one of the potential measures to achieve the sustainable development goals of the United Nations (UN). Therefore, this study reviews the most recent studies from relevant academic literature on WtE technology (particularly AD technology) for biogas production and the application of a solar-assisted biodigester (SAB) system aimed at improving performance. In addition, socio-economic factors, challenges, and perspectives have been reported. From the analysis of different technologies, further work on effective low-cost technologies is recommended, especially using SAB system upgrading and leveraging the opportunities of this system. The study found that the performance of the AD system is affected by a variety of factors and that different approaches can be applied to improve performance. It has also been found that solar energy systems efficiently raise the biogas digester temperature and through this, they maximize the biogas yield under optimum conditions. The study revealed that the solar-assisted AD system produces less pollution and improves performance compared to the conventional AD system.
Mannina, G, Alliet, M, Brepols, C, Comas, J, Harmand, J, Heran, M, Kalboussi, N, Makinia, J, Robles, Á, Rebouças, TF, Ni, B-J, Rodriguez-Roda, I, Victoria Ruano, M, Bertanza, G & Smets, I 2021, 'Integrated membrane bioreactors modelling: A review on new comprehensive modelling framework', Bioresource Technology, vol. 329, pp. 124828-124828.
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Integrated Membrane Bioreactor (MBR) models, combination of biological and physical models, have been representing powerful tools for the accomplishment of high environmental sustainability. This paper, produced by the International Water Association (IWA) Task Group on Membrane Modelling and Control, reviews the state-of-the-art, identifying gaps for future researches, and proposes a new integrated MBR modelling framework. In particular, the framework aims to guide researchers and managers in pursuing good performances of MBRs in terms of effluent quality, operating costs (such as membrane fouling, energy consumption due to aeration) and mitigation of greenhouse gas emissions.
Mazaheri, H, Ong, HC, Amini, Z, Masjuki, HH, Mofijur, M, Su, CH, Anjum Badruddin, I & Khan, TMY 2021, 'An Overview of Biodiesel Production via Calcium Oxide Based Catalysts: Current State and Perspective', Energies, vol. 14, no. 13, pp. 3950-3950.
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Biodiesel is a clean, renewable, liquid fuel that can be used in existing diesel engines without modification as pure or blend. Transesterification (the primary process for biodiesel generation) via heterogeneous catalysis using low-cost waste feedstocks for catalyst synthesis improves the economics of biodiesel production. Heterogeneous catalysts are preferred for the industrial generation of biodiesel due to their robustness and low costs due to the easy separation and relatively higher reusability. Calcium oxides found in abundance in nature, e.g., in seashells and eggshells, are promising candidates for the synthesis of heterogeneous catalysts. However, process improvements are required to design productive calcium oxide-based catalysts at an industrial scale. The current work presents an overview of the biodiesel production advancements using calcium oxide-based catalysts (e.g., pure, supported, and mixed with metal oxides). The review discusses different factors involved in the synthesis of calcium oxide-based catalysts, and the effect of reaction parameters on the biodiesel yield of calcium oxide-based catalysis are studied. Further, the common reactor designs used for the heterogeneous catalysis using calcium oxide-based catalysts are explained. Moreover, the catalytic activity mechanism, challenges and prospects of the application of calcium oxide-based catalysts in biodiesel generation are discussed. The study of calcium oxide-based catalyst should continue to be evaluated for the potential of their application in the commercial sector as they remain the pivotal goal of these studies.
Mazlan, M, Najafi, G, Hoseini, SS, Mamat, R, Alenzi, RA, Mofijur, M & Yusaf, T 2021, 'Thermal efficiency analysis of a nanofluid-based micro combined heat and power system using CNG and biogas', Energy, vol. 231, pp. 120870-120870.
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In the present study, a micro combined heat and power (micro-CHP) system using compressed natural gas (CNG) and biogas fuels, was developed. The objective of this research study was to investigate the utilization of nanofluids as a working fluid to improve thermal performance of the micro-CHP system. Three different nanofluids based on the CNT, Al2O3, and SiO2 have been investigated. The nanofluids was used as the circulating fluid to recover the heating power from the micro-CHP system. Three different concentration of nanoparticles (25, 50 and 100 ppm) have been used. The efficiency of separated heat and power (SHP) system was 27.6% while using combined heat and power, the total efficiency increased up to 65.3%. The results showed that by using CNG gas thermal efficiency of micro-CHP improve compared to the biogas. The result of the present study showed that nanofluids enhances the thermal efficiency of the micro-CHP system. By using the Al2O3 nanofluid the efficiency of micro-CHP efficiency is 73%. While by using the SiO2 and CNTs nanofluids the efficiency of micro-CHP efficiency is 70% and 66.3% respectively. So, we can coclude that by using the Al2O3 nanofluid thermal performance of micro-CHP systems improves.
Mazlan, M, Rahmani-dehnavi, M, Najafi, G, Ghobadian, B, Hoseini, SS, Fayyazi, E, Mamat, R, Alenezi, RA & Mofijur, M 2021, 'Thermal efficiency analysis of the phase change material (PCM) microcapsules', Sustainable Energy Technologies and Assessments, vol. 48, pp. 101557-101557.
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The aim of the present study is to evaluate the thermal behavior of cylindrical modules in a thermal energy storage unit as a combined sensible and latent heat. A thermal energy storage unit is designed, fabricated, and connected to a cold and hot water supply at constant temperatures to monitor the performance of the storage unit. The thermal energy storage unit contains the cylindrical microcapsules containing paraffin waxes as a phase change material which is located inside an insulating cylinder storage tank. Water is used as a heat transfer fluid to transfer heat from a hot water reservoir to the thermal energy storage unit during the phase change material charging process and also during the discharging process water receives heat from the thermal energy storage unit. Charge tests are carried out at the constant temperature. Moreover, the effect of different inlet flow on storage unit performance is investigated. Data were analyzed using Design Expert software and regression analysis which indicated that the increase of charge inlet temperature and charge inlet flow leads to the increase of heat power, thermal performance of thermal energy storage unit, and output variables. In comparison to the heat storage system without phase change material, microcapsules phase change material can improve the heat power of the heat storage system. Also, based on the optimization process, the maximum thermal performance of 96.4% and the maximum heat power level of 1.7 kW can be achieved in the optimized condition of the charging inlet temperature of 75 °C, charging inlet flow of 1.8−4 m3/s, and discharging inlet temperature of 35 °C.
Merenda, A, Bortolassi, ACC, Rodriguez-Andres, J, Al-Attabi, R, Schütz, JA, Kujawski, W, Shon, HK & Dumée, LF 2021, 'Hybrid polymer/ionic liquid electrospun membranes with tunable surface charge for virus capture in aqueous environments', Journal of Water Process Engineering, vol. 43, pp. 102278-102278.
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Mofijur, M, Ahmed, SF, Rahman, SMA, Arafat Siddiki, SKY, Islam, ABMS, Shahabuddin, M, Ong, HC, Mahlia, TMI, Djavanroodi, F & Show, PL 2021, 'Source, distribution and emerging threat of micro- and nanoplastics to marine organism and human health: Socio-economic impact and management strategies', Environmental Research, vol. 195, pp. 110857-110857.
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The nature of micro- and nanoplastics and their harmful consequences has drawn significant attention in recent years in the context of environmental protection. Therefore, this paper aims to provide an overview of the existing literature related to this evolving subject, focusing on the documented human health and marine environment impacts of micro- and nanoplastics and including a discussion of the economic challenges and strategies to mitigate this waste problem. The study highlights the micro- and nanoplastics distribution across various trophic levels of the food web, and in different organs in infected animals which is possible due to their reduced size and their lightweight, multi-coloured and abundant features. Consequently, micro- and nanoplastics pose significant risks to marine organisms and human health in the form of cytotoxicity, acute reactions, and undesirable immune responses. They affect several sectors including aquaculture, agriculture, fisheries, transportation, industrial sectors, power generation, tourism, and local authorities causing considerable economic losses. This can be minimised by identifying key sources of environmental plastic contamination and educating the public, thus reducing the transfer of micro- and nanoplastics into the environment. Furthermore, the exploitation of the potential of microorganisms, particularly those from marine origins that can degrade plastics, could offer an enhanced and environmentally sound approach to mitigate micro- and nanoplastics pollution.
Mofijur, M, Fattah, IMR, Alam, MA, Islam, ABMS, Ong, HC, Rahman, SMA, Najafi, G, Ahmed, SF, Uddin, MA & Mahlia, TMI 2021, 'Impact of COVID-19 on the social, economic, environmental and energy domains: Lessons learnt from a global pandemic', Sustainable Production and Consumption, vol. 26, pp. 343-359.
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COVID-19 has heightened human suffering, undermined the economy, turned the lives of billions of people around the globe upside down, and significantly affected the health, economic, environmental and social domains. This study aims to provide a comprehensive analysis of the impact of the COVID-19 outbreak on the ecological domain, the energy sector, society and the economy and investigate the global preventive measures taken to reduce the transmission of COVID-19. This analysis unpacks the key responses to COVID-19, the efficacy of current initiatives, and summarises the lessons learnt as an update on the information available to authorities, business and industry. This review found that a 72-hour delay in the collection and disposal of waste from infected households and quarantine facilities is crucial to controlling the spread of the virus. Broad sector by sector plans for socio-economic growth as well as a robust entrepreneurship-friendly economy is needed for the business to be sustainable at the peak of the pandemic. The socio-economic crisis has reshaped investment in energy and affected the energy sector significantly with most investment activity facing disruption due to mobility restrictions. Delays in energy projects are expected to create uncertainty in the years ahead. This report will benefit governments, leaders, energy firms and customers in addressing a pandemic-like situation in the future.
Mofijur, M, Fattah, IMR, Kumar, PS, Siddiki, SYA, Rahman, SMA, Ahmed, SF, Ong, HC, Lam, SS, Badruddin, IA, Khan, TMY & Mahlia, TMI 2021, 'Bioenergy recovery potential through the treatment of the meat processing industry waste in Australia', Journal of Environmental Chemical Engineering, vol. 9, no. 4, pp. 105657-105657.
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The farm animal and meat processing industry generate waste, including manure, fat, blood, sludge, bones, and wastewater, which create environmental problems worldwide. The effluents generated by this industry are rich in proteins, lipids, fibres, and carbohydrates. All these pollutants have the potential to be used as a resource for energy recovery. The organic matters obtained from the farm animal and meat processing industry are critical sources for biogas production via anaerobic digestion. This process leads to the production of energy-rich biogas, reducing greenhouse gas emissions. This study attempts to determine biogas amount and the energy value produced from the farm animal and meat processing industry in Australia. Australia's livestock population mainly consists of dairy cattle, meat cattle, sheep and lambs, pigs, layers, and meat chickens. Results show a potential biogas amount of 23,874,165 million m3 (Mm3), 215,670 Mm3, 288,228 Mm3, 18,430 Mm3, and 392,284 Mm3 can be obtained from cattle, lamb, sheep, pig, and poultry annually, respectively. The methane generated from slaughterhouse waste and wastewater is estimated to provide 4.52E+ 14 MJ/yr of heat energy with total electricity generation potential from livestock wastes of 4.4E+ 13 kWh/yr. About half of the electricity can be generated in Queensland State. Finally, the present study suggests farm animal and meat processing industry effluent as a potential sustainable energy source in Australia.
Mofijur, M, Siddiki, SYA, Shuvho, MBA, Djavanroodi, F, Fattah, IMR, Ong, HC, Chowdhury, MA & Mahlia, TMI 2021, 'Effect of nanocatalysts on the transesterification reaction of first, second and third generation biodiesel sources- A mini-review', Chemosphere, vol. 270, pp. 128642-128642.
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Biodiesel is a fuel that has numerous benefits over traditional petrodiesel. The transesterification process is the most popular method for biodiesel production from various sources, categorized as first, second and third generation biodiesel depending on the source. The transesterification process is subject to a variety of factors that can be taken into account to improve biodiesel yield. One of the factors is catalyst type and concentration, which plays a significant role in the transesterification of biodiesel sources. At present, chemical and biological catalysts are being investigated and each catalyst has its advantages and disadvantages. Recently, nanocatalysts have drawn researchers' attention to the efficient production of biodiesel. This article discusses recent work on the role of several nanocatalysts in the transesterification reaction of various sources in the development of biodiesel. A large number of literature from highly rated journals in scientific indexes is reviewed, including the most recent publications. Most of the authors reported that nanocatalysts show an important influence regarding activity and selectivity. This study highlights that in contrast to conventional catalysts, the highly variable surface area of nanostructure materials favours interaction between catalysts and substrates that efficiently boost the performance of products. Finally, this analysis provides useful information to researchers in developing and processing cost-effective biodiesel.
Mohanty, SS, Koul, Y, Varjani, S, Pandey, A, Ngo, HH, Chang, J-S, Wong, JWC & Bui, X-T 2021, 'A critical review on various feedstocks as sustainable substrates for biosurfactants production: a way towards cleaner production', Microbial Cell Factories, vol. 20, no. 1, p. 120.
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AbstractThe quest for a chemical surfactant substitute has been fuelled by increased environmental awareness. The benefits that biosurfactants present like biodegradability, and biocompatibility over their chemical and synthetic counterparts has contributed immensely to their popularity and use in various industries such as petrochemicals, mining, metallurgy, agrochemicals, fertilizers, beverages, cosmetics, etc. With the growing demand for biosurfactants, researchers are looking for low-cost waste materials to use them as substrates, which will lower the manufacturing costs while providing waste management services as an add-on benefit. The use of low-cost substrates will significantly reduce the cost of producing biosurfactants. This paper discusses the use of various feedstocks in the production of biosurfactants, which not only reduces the cost of waste treatment but also provides an opportunity to profit from the sale of the biosurfactant. Furthermore, it includes state-of-the-art information about employing municipal solid waste as a sustainable feedstock for biosurfactant production, which has not been simultaneously covered in many published literatures on biosurfactant production from different feedstocks. It also addresses the myriad of other issues associated with the processing of biosurfactants, as well as the methods used to address these issues and perspectives, which will move society towards cleaner production.
Mojiri, A, Zhou, JL, Ratnaweera, H, Ohashi, A, Ozaki, N, Aoi, Y, Vakili, M & Kindaichi, T 2021, 'Performance optimization of a chitosan/anammox reactor in nitrogen removal from synthetic wastewater', Journal of Environmental Chemical Engineering, vol. 9, no. 3, pp. 105252-105252.
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Anaerobic ammonia oxidation (anammox) is an environmentally friendly, cost-effective, and biological method for nitrogen treatment from aqueous solutions. However, slow growth rate, negative effects of high concentration of nitrite, ammonia and other pollutants (such as metals) on anammox activity are the main drawbacks of using anammox. Thus, in this study, anammox was attached on chitosan to improve anammox performance. Two reactors comprising chitosan and anammox bacteria (first reactor, chitosan/anammox) and solely anammox (second reactor, control) were run for 73 d. The nitrogen loading rate (NLR) varied from 2 to 14 (gN/L/d), while the nitrogen concentration varied from 80 to 700 mg/L. The chitosan/anammox reactor showed a better performance than the sole anammox (control), with respective maximum abatement values of ammonia (NH4+), nitrite (NO2-), and total nitrogen (TN) of 90.8%, 83.5%, and 81.7% on days 20-25 under a NLR of 8-10 kgTN/(m3 d). Response surface methodology (RSM) was employed to optimize the performance of both reactors, and a reasonable R2 value showed that the RSM well optimized the performance of the reactors. After finding the optimum performance conditions for both reactors, Fe and Cu (0.5-7.0 mg/L) were added to the influent to monitor the effects of metals on the performance of both reactors. The performance of both reactors decreased to 0% following the addition of 7.0 (first reactor) and 6.5 (second reactor) mg/L Cu and Fe, respectively. This indicated that chitosan not only enhanced nitrogen removal by anammox but also improved the resistance of anammox to metals.
Mojiri, A, Zhou, JL, Ratnaweera, H, Ohashi, A, Ozaki, N, Kindaichi, T & Asakura, H 2021, 'Treatment of landfill leachate with different techniques: an overview', Journal of Water Reuse and Desalination, vol. 11, no. 1, pp. 66-96.
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AbstractLandfill leachate is characterised by high chemical and biological oxygen demand and generally consists of undesirable substances such as organic and inorganic contaminants. Landfill leachate may differ depending on the content and age of landfill contents, the degradation procedure, climate and hydrological conditions. We aimed to explain the characteristics of landfill leachate and define the practicality of using different techniques for treating landfill leachate. Different treatments comprising biological methods (e.g. bioreactors, bioremediation and phytoremediation) and physicochemical approaches (e.g. advanced oxidation processes, adsorption, coagulation/flocculation and membrane filtration) were investigated in this study. Membrane bioreactors and integrated biological techniques, including integrated anaerobic ammonium oxidation and nitrification/denitrification processes, have demonstrated high performance in ammonia and nitrogen elimination, with a removal effectiveness of more than 90%. Moreover, improved elimination efficiency for suspended solids and turbidity has been achieved by coagulation/flocculation techniques. In addition, improved elimination of metals can be attained by combining different treatment techniques, with a removal effectiveness of 40–100%. Furthermore, combined treatment techniques for treating landfill leachate, owing to its high chemical oxygen demand and concentrations of ammonia and low biodegradability, have been reported with good performance. However, further study is necessary to enhance treatment methods to achieve maximum removal efficiency.
Moldovan, D, Choi, J, Choo, Y, Kim, W-S & Hwa, Y 2021, 'Laser-based three-dimensional manufacturing technologies for rechargeable batteries', Nano Convergence, vol. 8, no. 1, p. 23.
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AbstractLaser three-dimensional (3D) manufacturing technologies have gained substantial attention to fabricate 3D structured electrochemical rechargeable batteries. Laser 3D manufacturing techniques offer excellent 3D microstructure controllability, good design flexibility, process simplicity, and high energy and cost efficiencies, which are beneficial for rechargeable battery cell manufacturing. In this review, notable progress in development of the rechargeable battery cells via laser 3D manufacturing techniques is introduced and discussed. The basic concepts and remarkable achievements of four representative laser 3D manufacturing techniques such as selective laser sintering (or melting) techniques, direct laser writing for graphene-based electrodes, laser-induced forward transfer technique and laser ablation subtractive manufacturing are highlighted. Finally, major challenges and prospects of the laser 3D manufacturing technologies for battery cell manufacturing will be provided.
Muhammad, G, Alam, MA, Mofijur, M, Jahirul, MI, Lv, Y, Xiong, W, Ong, HC & Xu, J 2021, 'Modern developmental aspects in the field of economical harvesting and biodiesel production from microalgae biomass', Renewable and Sustainable Energy Reviews, vol. 135, pp. 110209-110209.
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Microalgae have been widely explored because of the diverse number of their worthwhile applications and potential as a source biomass for the production of biofuels and value-added materials. However, downstream techniques have yet to be fully developed to overcome techno-economic barriers. Flocculation is a superior method for harvesting microalgae from growth medium because of its harvesting efficiency, economic feasibility. Various kind of bio-flocculation harvesting methods are consider as attractive low cost and environmentally friendly options and able to harvest >90% biomass. Lipid recovery from microalgal cells is a major barrier for the biofuel industry because of process complexity and algae cell structure. Thus, the pretreatment method is necessary to disrupt the cell walls of microalgae and enhance lipid extraction. Many techniques, including dry methods of extraction, are already being implemented but found out that they are not efficient and cost-effective. Various new wet harvesting strategies have been claimed to extract major lipids in cost-efficient (30% less than conventional) way as wet technologies can eliminate the cost of cell drying and associated instruments. It is necessary to develop new methods which are energy and cost-effective, and environmentally friendlier for the commercialization of biofuels. Therefore, this review presents the advances in the progress of various flocculation harvesting methods with special emphasis on innovative bio-flocculation, the underlying mechanism of microalgae and flocculation. In this study also summarize the recent progress on microalgal oil extraction processes, and comparison was made between the processes in terms of sustainability, technology readiness, and applications in larger scales.
Mujtaba, MA, Muk Cho, H, Masjuki, HH, Kalam, MA, Farooq, M, Soudagar, MEM, Gul, M, Ahmed, W, Afzal, A, Bashir, S, Raju, VD, Yaqoob, H & Syahir, AZ 2021, 'Effect of alcoholic and nano-particles additives on tribological properties of diesel–palm–sesame–biodiesel blends', Energy Reports, vol. 7, pp. 1162-1171.
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Naji, O, Al-juboori, RA, Khan, A, Yadav, S, Altaee, A, Alpatova, A, Soukane, S & Ghaffour, N 2021, 'Ultrasound-assisted membrane technologies for fouling control and performance improvement: A review', Journal of Water Process Engineering, vol. 43, pp. 102268-102268.
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Naveed, M, Arslan, A, Javed, HMA, Manzoor, T, Quazi, MM, Imran, T, Zulfattah, ZM, Khurram, M & Fattah, IMR 2021, 'State-of-the-Art and Future Perspectives of Environmentally Friendly Machining Using Biodegradable Cutting Fluids', Energies, vol. 14, no. 16, pp. 4816-4816.
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The use of cutting fluids has played a vital role in machining operations in lubrication and cooling. Most cutting fluids are mineral oil-based products that are hazardous to the environment and the worker, cause severe diseases and pollute the environment. In addition, petroleum resources are becoming increasingly unsustainable. Due to environmental and health issues, legislations have been established to ensure that the consumption of mineral oil is reduced. Consequently, researchers are making efforts to replace these mineral oil-based products. Vegetable oils are grasping attention due to their better lubricating properties, ease of availability, biodegradability, low prices, and non-toxicity. In this study, a detailed review and critical analysis are conducted of the research works involving vegetable oils as cutting fluids keeping in view the shortcomings and possible solutions to overcome these drawbacks. The purpose of the review is to emphasise the benefits of vegetable oil-based cutting fluids exhibiting comparable performance to that of mineral oil-based products. In addition, an appropriate selection of non-edible vegetable oil-based cutting fluids along with optimum cutting parameters to avoid a scanty supply of edible oils is also discussed. According to this research, vegetable oils are capable of substituting synthetic cutting fluids, and this option might aid in the successful and cost-efficient implementation of green machining.
Ng, ECY, Huang, Y, Hong, G, Zhou, JL & Surawski, NC 2021, 'Reducing vehicle fuel consumption and exhaust emissions from the application of a green-safety device under real driving', Science of The Total Environment, vol. 793, pp. 148602-148602.
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Vehicle emissions have a significantly negative impact on climate change, air quality and human health. Drivers of vehicles are the last major and often overlooked factor that determines vehicle performance. Eco-driving is a relatively low-cost and immediate measure to reduce fuel consumption and emissions significantly. This paper reports investigation of the effects of an on-board green-safety device on fuel consumption and emissions for both experienced and inexperienced drivers. A portable emissions measurement system (PEMS) was installed on a diesel light goods vehicle (LGV) to measure real-driving emissions (RDE), including total hydrocarbons (THC), CO CO2, NO, NO2 and particulate matter (PM). In addition, driving parameters (e.g. vehicle speed and acceleration) and environmental parameters (e.g. ambient temperature, humidity and pressure) were recorded in the experiments. The experimental results were evaluated using the Vehicle Specific Power (VSP) methodology to understand the effects of driving behavior on fuel consumption and emissions. The results indicated that driving behavior was improved for both experienced and inexperienced drivers after activation of the on-board green-safety device. In addition, the average time spent was shifted from higher to lower VSP modes by avoiding excessive speed, and aggressive accelerations and decelerations. For experienced drivers, the average fuel consumption and NO, NO2 and soot emissions were reduced by 5%, 56%, 39% and 35%, respectively, with the on-board green-safety device. For inexperienced drivers, the average reductions were 6%, 65%, 50% and 19%, respectively. Moreover, the long-term formed habits of experienced drivers are harder to be changed to accept the assistance of the green-safety device, whereas inexperienced drivers are likely to be more receptive to change and improve their driving behaviors.
Nghiem, LD, Iqbal, HMN & Zdarta, J 2021, 'The shadow pandemic of single use personal protective equipment plastic waste: A blue print for suppression and eradication', Case Studies in Chemical and Environmental Engineering, vol. 4, pp. 100125-100125.
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Ngo, MTT, Ueyama, T, Makabe, R, Bui, X-T, Nghiem, LD, Nga, TTV & Fujioka, T 2021, 'Fouling behavior and performance of a submerged flat-sheet nanofiltration membrane system for direct treatment of secondary wastewater effluent', Journal of Water Process Engineering, vol. 41, pp. 101991-101991.
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Nguyen, AQ, Vu, HP, Nguyen, LN, Wang, Q, Djordjevic, SP, Donner, E, Yin, H & Nghiem, LD 2021, 'Monitoring antibiotic resistance genes in wastewater treatment: Current strategies and future challenges', Science of The Total Environment, vol. 783, pp. 146964-146964.
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Antimicrobial resistance (AMR) is a growing threat to human and animal health. Progress in molecular biology has revealed new and significant challenges for AMR mitigation given the immense diversity of antibiotic resistance genes (ARGs), the complexity of ARG transfer, and the broad range of omnipresent factors contributing to AMR. Municipal, hospital and abattoir wastewater are collected and treated in wastewater treatment plants (WWTPs), where the presence of diverse selection pressures together with a highly concentrated consortium of pathogenic/commensal microbes create favourable conditions for the transfer of ARGs and proliferation of antibiotic resistant bacteria (ARB). The rapid emergence of antibiotic resistant pathogens of clinical and veterinary significance over the past 80 years has re-defined the role of WWTPs as a focal point in the fight against AMR. By reviewing the occurrence of ARGs in wastewater and sludge and the current technologies used to quantify ARGs and identify ARB, this paper provides a research roadmap to address existing challenges in AMR control via wastewater treatment. Wastewater treatment is a double-edged sword that can act as either a pathway for AMR spread or as a barrier to reduce the environmental release of anthropogenic AMR. State of the art ARB identification technologies, such as metagenomic sequencing and fluorescence-activated cell sorting, have enriched ARG/ARB databases, unveiled keystone species in AMR networks, and improved the resolution of AMR dissemination models. Data and information provided in this review highlight significant knowledge gaps. These include inconsistencies in ARG reporting units, lack of ARG/ARB monitoring surrogates, lack of a standardised protocol for determining ARG removal via wastewater treatments, and the inability to support appropriate risk assessment. This is due to a lack of standard monitoring targets and agreed threshold values, and paucity of information on the ARG-pat...
Nguyen, HM, Ralph, PJ, Marín‐Guirao, L, Pernice, M & Procaccini, G 2021, 'Seagrasses in an era of ocean warming: a review', Biological Reviews, vol. 96, no. 5, pp. 2009-2030.
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ABSTRACTSeagrasses are valuable sources of food and habitat for marine life and are one of Earth's most efficient carbon sinks. However, they are facing a global decline due to ocean warming and eutrophication. In the last decade, with the advent of new technology and molecular advances, there has been a dramatic increase in the number of studies focusing on the effects of ocean warming on seagrasses. Here, we provide a comprehensive review of the future of seagrasses in an era of ocean warming. We have gathered information from published studies to identify potential commonalities in the effects of warming and the responses of seagrasses across four distinct levels: molecular, biochemical/physiological, morphological/population, and ecosystem/planetary. To date, we know that although warming strongly affects seagrasses at all four levels, seagrass responses diverge amongst species, populations, and over depths. Furthermore, warming alters seagrass distribution causing massive die‐offs in some seagrass populations, whilst also causing tropicalization and migration of temperate species. In this review, we evaluate the combined effects of ocean warming with other environmental stressors and emphasize the need for multiple‐stressor studies to provide a deeper understanding of seagrass resilience. We conclude by discussing the most significant knowledge gaps and future directions for seagrass research.
Nguyen, HT, Yoon, Y, Ngo, HH & Jang, A 2021, 'The application of microalgae in removing organic micropollutants in wastewater', Critical Reviews in Environmental Science and Technology, vol. 51, no. 12, pp. 1187-1220.
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© 2020, © 2020 Taylor & Francis Group, LLC. Micropollutants have become a serious environmental problem with several negative outcomes for human health and ecosystems. Many efforts have been made to remove micropollutants using a variety of physical, chemical and biological methods. By far, the most attention has been paid to microalgae-based technologies for wastewater treatment in order to obtain high-quality effluents, recover algal biomass for fertilizers, protein-rich feed, biofuel, and put them to other practical use. This paper reviews the potential of microalgae-based systems for the removal of organic micropollutants from open ponds to closed photobioreactors coupled by suspended microalgal cells, immobilized cells, or microalgae-microbial consortia. The inhibition of micropollutants on microalgae growth as well as micropollutant removal mechanisms performed by microalgae-based systems are also discussed. Other treatment methods for the removal of micropollutants are analyzed to show the advantages and limitations of microalgae-based treatment strategies, from which some possible combined systems can be suggested. Finally, some recommendations for future studies on this topic are proposed. (Figure presented.).
Nguyen, KT, Ahmed, MB, Mojiri, A, Huang, Y, Zhou, JL & Li, D 2021, 'Advances in As contamination and adsorption in soil for effective management', Journal of Environmental Management, vol. 296, pp. 113274-113274.
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Arsenic (As) is a heavy metal that causes widespread contamination and toxicity in the soil environment. This article reviewed the levels of As contamination in soils worldwide, and evaluated how soil properties (pH, clay mineral, organic matter, texture) and environmental conditions (ionic strength, anions, bacteria) affected the adsorption of As species on soils. The application of the adsorption isotherm models for estimating the adsorption capacities of As(III) and As(V) on soils was assessed. The results indicated that As concentrations in contaminated soil varying significantly from 1 mg/kg to 116,000 mg/kg, with the highest concentrations being reported in Mexico with mining being the dominating source. Regarding the controlling factors of As adsorption, soil pH, clay mineral and texture had demonstrated the most significant impacts. Both Langmuir and Freundlich isotherm models can be well fitted with As(III) and As(V) adsorption on soils. The Langmuir adsorption capacity varied in the range of 22-42400 mg/kg for As(V), which is greater than 45-8901 mg/kg for As(III). The research findings have enhanced our knowledge of As contamination in soil and its underlying controls, which are critical for the effective management and remediation of As-contaminated soil.
Nguyen, LN, Kumar, J, Vu, MT, Mohammed, JAH, Pathak, N, Commault, AS, Sutherland, D, Zdarta, J, Tyagi, VK & Nghiem, LD 2021, 'Biomethane production from anaerobic co-digestion at wastewater treatment plants: A critical review on development and innovations in biogas upgrading techniques', Science of The Total Environment, vol. 765, pp. 142753-142753.
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Anaerobic co-digestion (AcoD) can utilise spare digestion capacity at existing wastewater treatment plants (WWTP) to generate surplus biogas beyond the plant's internal energy requirement. Data from industry reports and the peer-reviewed literature show that through AcoD, numerous examples of WWTPs have become net energy producers, necessitating other high-value applications for surplus biogas. A globally emerging trend is to upgrade biogas to biomethane, which can then be used as town gas or transport fuel. Water, organic solvent and chemical scrubbing, pressure swing adsorption, membrane separation, and cryogenic technology are commercially available CO2 removal technologies for biogas upgrade. Although water scrubbing is currently the most widely applied technology due to low capital and operation cost, significant market growth in membrane separation has been seen over the 2015-2019 period. Further progress in materials engineering and sciences is expected and will further enhance the membrane separation competitiveness for biogas upgrading. Several emerging biotechnologies to i) improve biogas quality from AcoD; ii) accelerate the absorption rate, and iii) captures CO2 in microalgal culture have also been examined and discussed in this review. Through a combination of AcoD and biogas upgrade, more WWTPs are expected to become net energy producers.
Nguyen, LN, Vu, MT, Abu Hasan Johir, M, Pernice, M, Ngo, HH, Zdarta, J, Jesionowski, T & Nghiem, LD 2021, 'Promotion of direct interspecies electron transfer and potential impact of conductive materials in anaerobic digestion and its downstream processing - a critical review', Bioresource Technology, vol. 341, pp. 125847-125847.
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Nguyen, MK, Tran, VS, Pham, TT, Pham, HG, Hoang, BL, Nguyen, TH, Nguyen, TH, Tran, TH & Ngo, HH 2021, 'Fenton/ozone-based oxidation and coagulation processes for removing metals (Cu, Ni)-EDTA from plating wastewater', Journal of Water Process Engineering, vol. 39, pp. 101836-101836.
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Wastewater containing heavy metals has caused many serious problems to land and marine environments. These heavy metal-laden wastewaters containing organic complexing agents are the consequence of using large-scale industrial applications for dissolving metals. Ethylenediaminetetraacetate (EDTA) is a widely used complexing agent in plating, metal finishing and chemical cleaning industries. However, due to the dramatic increase in the solubility of metal ions, EDTA has negative impact on heavy metals removed in wastewaters by conventional precipitation processes. This study aims to find the optimal conditions of combined/hybrid process of advanced oxidation and coagulation to treat metals-EDTA containing Cu, Ni plating wastewater from an electroplating manufacturer in Vietnam. The effects of pH, H2O2 dose, Fe2+ dose, ozone, reaction time and poly acrylic acid (PAA) dose were investigated. Results indicated that the 3-stage treatment process at the optimal conditions could remove 99.7 % of Ni and 99.72 % of Cu. The effluent of wastewater after the whole treatment process met the Vietnamese national regulation on industrial wastewater (QCVN 40:2011/BTNMT) for NH4+, Cu and Ni at column A and COD at column B. In short, the combined advanced oxidation processes and coagulation/flocculation could successfully be applied for plating wastewater treatment.
Nguyen, P-D, Tran, N-ST, Nguyen, T-T, Dang, B-T, Le, M-TT, Bui, X-T, Mukai, F, Kobayashi, H & Ngo, HH 2021, 'Long-term operation of the pilot scale two-stage anaerobic digestion of municipal biowaste in Ho Chi Minh City', Science of The Total Environment, vol. 766, pp. 142562-142562.
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A pilot-scale two-stage anaerobic digestion system, which includes a feed tank (0.4 m3), a hydrolysis reactor (1.2 m3) followed by a methane fermenter (4.0 m3) was set up and run at the municipal solid waste landfill located in Ho Chi Minh City (HCMC), Vietnam. The feed that was separated from urban organic solid waste was collected at households and restaurants in District 1, HCMC. This study aimed to investigate the resource recovery performance of the pilot two-stage anaerobic digestion system, in terms of carbon recovery via biogas production and nutrient recovery from digestate. The average organic loading rate (OLR) of the system was step increased from 1.6 kg volatile solids (VS)·m-3·d-1, 2.5 kg VS·m-3·d-1 and 3.8 kg VS·m-3·d-1 during 400 days of operation. During the long-term operation at three OLRs, pH values and alkalinity were stable at both hydrolysis and methanogenesis stages without any addition of alkalinity for the methanogenesis phase. High buildup of propanoic acid and total volatile fatty acid concentrations in the fermenter did not drop pH values and inhibit the methanogenic process at high OLRs (2.5-3.8 kg VS m-3·d-1). The obtained total chemical oxygen demand (tCOD) removal performance was 83-87% at the OLRs ranging from 2.5 kg VS·m-3·d-1 and 3.8 kg VS·m-3·d-1, respectively. The highest biogas yield of 263 ± 64 L·kg-1 tCOD removed obtained at OLR of 2.5 kg VS·m-3·d-1. It is expected that a full scale 2S-AD plant with capacity of 5200 tons day-1 of biowaste collected currently from municipal solid waste in HCMC may create daily electricity of 552 MWh, thermal energy of 630 MWh, and recovery of 16.1 tons of NH4+-N, 11.4 tons of organic-N, and 2.1 tons of TP as both organic liquid and solid fertilizers.
Nguyen, TH, Nguyen, AT, Loganathan, P, Nguyen, TV, Vigneswaran, S, Nguyen, THH & Tran, HN 2021, 'Low-cost laterite-laden household filters for removing arsenic from groundwater in Vietnam and waste management', Process Safety and Environmental Protection, vol. 152, pp. 154-163.
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Nguyen, TKL, Ngo, HH, Guo, W, Nghiem, LD, Qian, G, Liu, Q, Liu, J, Chen, Z, Bui, XT & Mainali, B 2021, 'Assessing the environmental impacts and greenhouse gas emissions from the common municipal wastewater treatment systems', Science of The Total Environment, vol. 801, pp. 149676-149676.
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This study measured the environmental impacts from three same-size wastewater treatment systems, specifically activated sludge, a constructed wetland, and a high rate algal pond. Detailed data inventories were employed using SimaPro 9 software to calculate the entire consequences by ReCiPe 2016 and Greenhouse Gas Protocol method. The environmental outcomes caused by substance emissions and resource extraction are presented in several impact categories at the endpoint level. For a better comparison, the single score tool was applied to aggregate all factors into three areas of protection: human health, ecosystem, and resource shortage. Results showed that concrete and steel are the main contributors to the construction phase, while electricity is responsible for the operation stage. The single score calculation indicates that the proportion of construction activities could be equal to or even higher than the operation stage for a small capacity plant. The total environmental impact of the conventional system was 2.3-fold and 3-fold higher than that of constructed wetland and high rate algal pond, respectively. High rate algal pond has the best environmental performance when generating the least burdens and greenhouse gas emissions of 0.72 kg CO2 equivalent per m3. Constructed wetland produces 5.69 kg CO2, higher than an algal pond but much lower than activated sludge plant, emitting 11.42 kg CO2 per m3.
Nguyen, TKL, Ngo, HH, Guo, W, Nguyen, TLH, Chang, SW, Nguyen, DD, Varjani, S, Lei, Z & Deng, L 2021, 'Environmental impacts and greenhouse gas emissions assessment for energy recovery and material recycle of the wastewater treatment plant', Science of The Total Environment, vol. 784, pp. 147135-147135.
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Nguyen, T-T, Bui, X-T, Ngo, HH, Nguyen, T-T-D, Nguyen, K-Q, Nguyen, H-H, Huynh, K-P-H, Némery, J, Fujioka, T, Duong, CH, Dang, B-T & Varjani, S 2021, 'Nutrient recovery and microalgae biomass production from urine by membrane photobioreactor at low biomass retention times', Science of The Total Environment, vol. 785, pp. 147423-147423.
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Urine has been considered as an ideal nutrient source for microalgae cultivation thanks to its composition containing the high concentrations of nitrogen and phosphorus. Herein, the microalgae growth in urine was evaluated in a lab-scale membrane photobioreactor (MPBR) system. This work aimed to validate the influence of low biomass retention times (BRT) (10, 7, 5, 3, 2 d) on nutrient remediation and biomass productivity. It revealed that BRT of 7 d resulted in synergistically high biomass production (biomass productivity of 313 mg/L.d) and removal rates (TN of 90.5 mg/L.d and TP of 4.7 mg/L.d). Notably, the short BRT of 2–5 d was not sufficient to trigger actively growing microalgae and thus reduced biomass production rate. In addition, as operated at a low flux of 2 L/m2.h, MPBR system required no physical cleaning for 100 days of operation. The BRT-dependent biomass concentration played a pivotal role in changing the fouling rate of MPBR; however, the fouling is reversible in the MPBR system under the low flux condition.
Nguyen, TTQ, Loganathan, P, Dinh, BK, Nguyen, TV, Vigneswaran, S & Ngo, HH 2021, 'Removing arsenate from water using batch and continuous-flow electrocoagulation with diverse power sources', Journal of Water Process Engineering, vol. 41, pp. 102028-102028.
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Nguyen, XC, Ly, QV, Li, J, Bae, H, Bui, X-T, Nguyen, TTH, Tran, QB, Vo, T-D-H & Nghiem, LD 2021, 'Nitrogen removal in subsurface constructed wetland: Assessment of the influence and prediction by data mining and machine learning', Environmental Technology & Innovation, vol. 23, pp. 101712-101712.
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Nguyen, XC, Ly, QV, Peng, W, Nguyen, V-H, Nguyen, DD, Tran, QB, Huyen Nguyen, TT, Sonne, C, Lam, SS, Ngo, HH, Goethals, P & Le, QV 2021, 'Vertical flow constructed wetlands using expanded clay and biochar for wastewater remediation: A comparative study and prediction of effluents using machine learning', Journal of Hazardous Materials, vol. 413, pp. 125426-125426.
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Nguyen, XC, Nguyen, TTH, Bui, X-T, Tran, XV, Tran, TCP, Hoang, NTT, La, DD, Chang, SW, Ngo, HH & Nguyen, DD 2021, 'Status of water use and potential of rainwater harvesting for replacing centralized supply system in remote mountainous areas: a case study', Environmental Science and Pollution Research, vol. 28, no. 45, pp. 63589-63598.
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The failure of the centralized water supply system forced XY community to become more dependent on uncertain and unstable water sources. The results of surveying 50 households showed that 89.18% of total households depended on water collected from rivers, which contributed 58.3% of the total water volume used for the domestic demands. The average water volume consumed was 19.5 liters/person/day (l/p/d), and 86.5% of households used more than one source; 13.5% of households collected water only from rivers, and 45.94% of families had rainwater harvesting (RWH) for their activities (domestic water demand); however, RWH only provided 9.9% of total water consumption. In this study, basic methods were applied to calculate the storage tanks necessary to balance the water deficit created by drought months. Three levels of water demand (14, 20, and 30 l/p/d) can be the best choices for RWH; for a higher demand (40 and 60 l/p/d), small roof area (30-40 m2), and many people (six to seven) per family, RWH might be impractical because of unsuitable rainfall or excessively large storage tanks.
Obeid, F, Van, TC, Guo, B, Surawski, NC, Hornung, U, Brown, RJ, Ramirez, JA, Thomas-Hall, SR, Stephens, E, Hankamer, B & Rainey, T 2021, 'The fate of nitrogen and sulphur during co-liquefaction of algae and bagasse: Experimental and multi-criterion decision analysis', Biomass and Bioenergy, vol. 151, pp. 106119-106119.
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The removal of nitrogen (N) and sulphur (S) from biocrude oil produced using hydrothermal liquefaction (HTL), is important for the production of high quality renewable fuels. Here the effect of co-liquefaction of bagasse and algae was analysed. Algae (Chlorella vulgaris and Cyanobacteria) were mixed with bagasse (1:1) subjected to HTL at 250–350 °C for 10–60 min. Higher HTL temperatures had a positive effect in increasing the biocrude yield and slightly reduced N content; S did not show a consistent trend. Most of the nitrogen (~66%) and sulphur (~80%) were recovered in the aqueous phase rather than in the biocrude phase, opening the opportunity to recycle these nutrients for algae cultivation. Co-liquefying bagasse with algae improved the biocrude yield (54 wt%) compared to pure Cyanobacteria (47.5 wt%). It also reduced N content from 7 wt% (Cyanobacteria biocrude) to 4.2 wt% (Cyanobacteria: Bagasse) and S from 0.7 wt% to 0.4 wt%. Principal Component Analysis (PCA) analysis identified that biocrude yield is positively correlated with the initial lipid content and anti-correlated with the carbohydrates fraction. Biocrude N content is closely related to the initial amount of proteins in the algae. The Preference Ranking Organization METHod for Enrichment of Evaluations and its descriptive complement Geometrical Analysis for Interactive Aid (PROMETHEE and GAIA) analysis ranked the co-liquefaction of Chlorella vulgaris and bagasse (1:1) at 350 °C and 60 min as one of the best overall combination in terms of biocrude yield, N and S content.
Ong, HC, Tiong, YW, Goh, BHH, Gan, YY, Mofijur, M, Fattah, IMR, Chong, CT, Alam, MA, Lee, HV, Silitonga, AS & Mahlia, TMI 2021, 'Recent advances in biodiesel production from agricultural products and microalgae using ionic liquids: Opportunities and challenges', Energy Conversion and Management, vol. 228, pp. 113647-113647.
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© 2020 Elsevier Ltd Biodiesel is considered as a potential substitute for petroleum-based diesel fuel owing to its comparable properties to diesel. Biodiesel is generally produced from renewable sources such as agricultural products and microalgae in the presence of a suitable catalyst. Recently ionic liquid (IL) catalyzed synthesis of biodiesel has become a promising pathway to an eco-friendly production route for biodiesel. This review focuses on the use of ILs both as solvents as well as catalysts for sustainable biodiesel production from agricultural feedstocks and microalgae with high free fatty acid content. Reactions catalyzed by ILs are known to render high reactivity under the mild condition and high selectivity of ester product with simple separation steps. The article first discusses the state of the art of biodiesel production using ILs along with the physicochemical properties of the produced biodiesel. Then, current IL technologies were elucidated in terms of the categories such as acidic and basic ILs. The use of more advanced ILs such as supported ionic liquids and ionic liquid-enzyme catalysts on different biodiesel feedstocks were also discussed. Furthermore, the role of IL catalyst in intensified biodiesel production methods such as microwave and ultrasound technologies were also discussed. Finally, the prospects and challenges of IL catalyzed biodiesel production are discussed in this article. The review shows that ILs with brønsted acidity or basicity not only pose a low risk to the environment but also result in high biodiesel yields with mild reaction conditions in a short time. Brønsted acidic ILs can convert free fatty acids as well as triglycerides to biodiesel without the need for pretreatment, which facilitates in reducing the production cost of biodiesel. From the review, it can be concluded that ILs present great potential as catalysts for biodiesel production.
Pan, S, Chen, X, Cao, C, Chen, Z, Hao Ngo, H, Shi, Q, Guo, W & Hu, H-Y 2021, 'Fluorescence analysis of centralized water supply systems: Indications for rapid cross-connection detection and water quality safety guarantee', Chemosphere, vol. 277, pp. 130290-130290.
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Park, MJ, Nisola, GM, Seo, DH, Wang, C, Phuntsho, S, Choo, Y, Chung, W-J & Shon, HK 2021, 'Chemically Cross-Linked Graphene Oxide as a Selective Layer on Electrospun Polyvinyl Alcohol Nanofiber Membrane for Nanofiltration Application', Nanomaterials, vol. 11, no. 11, pp. 2867-2867.
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Graphene oxide (GO) nanosheets were utilized as a selective layer on a highly porous polyvinyl alcohol (PVA) nanofiber support via a pressure-assisted self-assembly technique to synthesize composite nanofiltration membranes. The GO layer was rendered stable by cross-linking the nanosheets (GO-to-GO) and by linking them onto the support surface (GO-to-PVA) using glutaraldehyde (GA). The amounts of GO and GA deposited on the PVA substrate were varied to determine the optimum nanofiltration membrane both in terms of water flux and salt rejection performances. The successful GA cross-linking of GO interlayers and GO-PVA via acetalization was confirmed by FTIR and XPS analyses, which corroborated with other characterization results from contact angle and zeta potential measurements. Morphologies of the most effective membrane (CGOPVA-50) featured a defect-free GA cross-linked GO layer with a thickness of ~67 nm. The best solute rejections of the CGOPVA-50 membrane were 91.01% for Na2SO4 (20 mM), 98.12% for Eosin Y (10 mg/L), 76.92% for Methylene blue (10 mg/L), and 49.62% for NaCl (20 mM). These findings may provide one of the promising approaches in synthesizing mechanically stable GO-based thin-film composite membranes that are effective for solute separation via nanofiltration.
Park, MJ, Wang, C, Seo, DH, Gonzales, RR, Matsuyama, H & Shon, HK 2021, 'Inkjet printed single walled carbon nanotube as an interlayer for high performance thin film composite nanofiltration membrane', Journal of Membrane Science, vol. 620, pp. 118901-118901.
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Inkjet printing process enables rapid deposition of inks with precise amount and location. Moreover, the process can be automated and provide control such as repetitive printing of the inks. Utilizing the advantageous features of the inkjet printing process, we demonstrate the synthesis of thin film composite (TFC) flat-sheet membrane for NF application where single walled carbon nanotube (SWCNT) was deposited via an inkjet printing process, acting as an interlayer between the polyamide (PA) selective layer and polyethersulfone (PES) MF membrane support. By controlling the number of SWCNT printings on the PES membrane, we investigated how the SWCNT interlayer thickness influences the formation of PA selective layer. The best membrane performance was achieved from the TFC membrane synthesized using 15 cycles of SWCNT printing, where both high water flux (18.24 ± 0.43 L m−2 h−1 bar−1) and the high Na2SO4 salt rejection (97.88 ± 0.33%) rates were demonstrated. SWCNT interlayer provided highly porous, interconnected structure with uniform pore size distribution which led to the formation of a defect-free ultrathin PA selective layer. Designing of TFC membrane using the SWCNT deposition via inkjet printing is the new approach and successfully demonstrated the significant improvement in the NF membrane performances.
Parvin, K, Lipu, MSH, Hannan, MA, Abdullah, MA, Jern, KP, Begum, RA, Mansur, M, Muttaqi, KM, Mahlia, TMI & Dong, ZY 2021, 'Intelligent Controllers and Optimization Algorithms for Building Energy Management Towards Achieving Sustainable Development: Challenges and Prospects', IEEE Access, vol. 9, pp. 41577-41602.
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Peng, L, Fan, S-Q, Xie, G-J, Ni, B-J, Liu, Y, Xu, Y, Liu, B-F, Xing, D-F, Han, H-J, Song, S & Ren, N-Q 2021, 'Modeling nitrate/nitrite dependent anaerobic methane oxidation and Anammox process in a membrane granular sludge reactor', Chemical Engineering Journal, vol. 403, pp. 125822-125822.
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The granular bioreactor, characterized by excellent settling velocity, high rate and low cost is an ideal choice for achieving coupled nitrate/nitrite dependent denitrifying anaerobic methane oxidation (n-DAMO) and anaerobic ammonium oxidation (Anammox) process. To fundamentally understand its underlining mechanisms and provide suggestions for process optimization, a granule-based model framework was developed to describe simultaneous anaerobic methane and ammonium oxidation by functional microbes. The proposed model was evaluated based on long-term experimental data from two membrane granular sludge reactors (MGSRs) with different operational conditions. The model possessed of good predictive ability to reproduce removal rates and effluent concentrations of nitrogen species. The predicted biomass abundance in two MGSRs and stratified microbial distribution along granule depth were consistent with experimental observations. The estimated parameter values, with good identifiability and reliability indicated a stimulated growth of DAMO archaea in MGSRs. Both hydraulic retention times (HRTs) and granule sizes have influences on microbial abundance in the MGSR and community distribution inside granules. Within the investigated HRTs from 1.4 h to 20 h and granule sizes from 500 μm to 2900 μm, it was revealed that a proper control of relatively short HRTs and small granule sizes resulted in an increased fraction of DAMO archaea and a reduced DAMO bacteria abundance with AnAOB less impacted, which would lower the required nitrite nitrogen to ammonium nitrogen ratio in the nitritation reactor (prior unit) and thus minimize operational cost in sidestream treatment lines.
Pettit, T, Torpy, FR, Surawski, NC, Fleck, R & Irga, PJ 2021, 'Effective reduction of roadside air pollution with botanical biofiltration', Journal of Hazardous Materials, vol. 414, pp. 125566-125566.
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Punetha, P, Nimbalkar, S & Khabbaz, H 2021, 'Simplified geotechnical rheological model for simulating viscoelasto‐plastic response of ballasted railway substructure', International Journal for Numerical and Analytical Methods in Geomechanics, vol. 45, no. 14, pp. 2019-2047.
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AbstractA proper understanding of the mechanical behaviour of the substructure layers is crucial for optimising the design and performance of a ballasted railway track. The recent advent of high‐speed trains and heavy haul freight wagons has heightened this need more than ever. The accurate prediction of the long‐term performance of the railway tracks under increased speed and loads still remains an intriguing challenge for researchers and design engineers. In this context, the present paper proposes a simplified geotechnical rheological model to evaluate the viscoelasto‐plastic response of the track substructure layers. The proposed approach combines plastic slider, elastic springs and viscous dampers to predict the transient response during a train passage, and the irrecoverable deformation accumulated in the track substructure over an operational period. The model simulates tri‐layered substructure (ballast, subballast, and subgrade) in comparison with existing rheological approaches employing either single or dual‐layered substructure. The model is validated against the field data published in the literature. An acceptable agreement between the predicted results and the field data verifies the accuracy of the model. Parametric investigations are conducted to study the influence of train and track parameters on the cumulative track deformation. The results demonstrate the enhanced capability of the rheological model to adequately capture the crucial effects of axle load, train speed and thickness of granular layers on the accumulation of track settlement. The proposed method can provide an effective tool for the practising engineers for quick prediction of changes to the geometry of railway tracks over their operational periods.
Qamar, A, Kerdi, S, Ali, SM, Shon, HK, Vrouwenvelder, JS & Ghaffour, N 2021, 'Novel hole-pillar spacer design for improved hydrodynamics and biofouling mitigation in membrane filtration', Scientific Reports, vol. 11, no. 1.
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AbstractFeed spacers are the critical components of any spiral-wound filtration module, dictating the filtration performance. Three spacer designs, namely a non-woven commercial spacer (varying filament cross-section), a symmetric pillar spacer, and a novel hole-pillar spacer (constant filament diameter) were studied using Direct Numerical Simulations (DNS), 3-D printed and subsequently experimentally tested in a lab-scale ultrafiltration set-up with high biofouling potential feed water at various feed pressures. Independent of the applied pressure, the novel hole-pillar spacer showed initially the lowest feed channel pressure drop, the lowest shear stress, and the highest permeate flux compared to the commercial and pillar spacers. Furthermore, less biofilm thickness development on membrane surface was visualized by Optical Coherent Tomography (OCT) imaging for the proposed hole-pillar spacer. At higher feed pressure, a thicker biofilm developed on membrane surface for all spacer designs explaining the stronger decrease in permeate flux at high pressure. The findings systematically demonstrated the role of various spacer designs and applied pressure on the performance of pre-treatment process, while identifying specific shear stress distribution guidelines for engineering a new spacer design in different filtration techniques.
Rafa, N, Ahmed, SF, Badruddin, IA, Mofijur, M & Kamangar, S 2021, 'Strategies to Produce Cost-Effective Third-Generation Biofuel From Microalgae', Frontiers in Energy Research, vol. 9, pp. 1-11.
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Third-generation biofuel produced from microalgae is a viable solution to global energy insecurity and climate change. Despite an annual current global algal biomass production of 38 million litres, commercialization confronts significant economic challenges. However, cost minimization strategies, particularly for microalgae cultivation, have largely been excluded from recent studies. Therefore, this review provides essential insights into the technologies and economics of cost minimization strategies for large-scale applications. Cultivation of microalgae through aquafarming, in wastewater, or for biogas upgrading, and co-production of value-added products (VAPs) such as photo-bioreactors, protein, astaxanthin, and exopolysaccharides can drastically reduce biodiesel production costs. For instance, the co-production of photo-bioreactors and astaxanthin can reduce the cost of biodiesel production from $3.90 to $0.54 per litre. Though many technical challenges need to be addressed, the economic analysis reveals that incorporating such cost-effective strategies can make the biorefinery concept feasible and profitable. The cost of producing microalgal biodiesel can be lowered to $0.73kg−1dry weight when cultivated in wastewater or $0.54L−1when co-produced with VAPs. Most importantly, access to co-product markets with higher VAPs needs to be encouraged as the global market for microalgae-based VAPs is estimated to rise to $53.43 billion in 2026. Therefore, policies that incentivize research and development, as well as the production and consumption of microalgae-based biodiesel, are important to reduce the large gap in production cost that persists between biodiesel and petroleum diesel.
Rahaman, M, Hasan, MI, Mofijur, M, Rasul, MG, Hassan, NMS & Ong, HC 2021, 'Impact of Partial Alteration of Diesel Fuel on the Performance and Regulated Emission of a Diesel Engine', e-Prime, vol. 1, pp. 100007-100007.
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Rahman, A, Putra, JD, Prihantini, NB, Mahlia, TMI, Aziz, M, Deendarlianto & Nasruddin, N 2021, 'Cultivation of Synechococcus HS-9 in a novel rectangular bubble column photobioreactor with horizontal baffle', Case Studies in Thermal Engineering, vol. 27, pp. 101264-101264.
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Rahman, SMA, Fattah, IMR, Maitra, S & Mahlia, TMI 2021, 'A ranking scheme for biodiesel underpinned by critical physicochemical properties', Energy Conversion and Management, vol. 229, pp. 113742-113742.
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© 2020 Elsevier Ltd Diminishing oil reserve, escalating energy dependence, and the environmental impact of fossil fuel utilization has led to research on renewable energy resources with a cleaner carbon footprint. Biofuel, especially biodiesel, has become a feasible substitute for petroleum diesel as it can be directly used in existing transport infrastructure without significant alteration. This paper starts by discussing some critical physicochemical properties and their effect on engine performance and emission. The research then proposes a ranking scheme to select the most suitable biodiesel based on six vital physicochemical properties: density, viscosity, heating value, flash point, cetane number and oxidation stability. The solution developed is independent of supervision, contrary to popular learning algorithms and can operate on the only intelligence whether an attribute is favourable by its higher/lower values. The novelty of the work consists in ensuring that the rarer properties pick up the greater weights and in establishing a simple ranker based on descriptive statistics. This scheme first generates transactions against each biodiesel which helps in association rule mining, which is later used to score/rank the biodiesels. The three phases and their subordinate sub-steps have been carried out using the platforms: Python, R and Tableau, respectively. The study endorses Brassica juncea, Cardoon (Cynara cardunculu), and poppyseed oil as the most desirable biodiesel feedstocks. On the other hand, cedar, castor and hiptage were ranked as least desirable in the list of 71 feedstocks based on the proposed ranking scheme. The proposed ranking scheme will help decision-makers such to analyze and obtain tailored biodiesel feedstock for their purposes.
Rahman, SMA, Fattah, IMR, Ong, HC, Ashik, FR, Hassan, MM, Murshed, MT, Imran, MA, Rahman, MH, Rahman, MA, Hasan, MAM & Mahlia, TMI 2021, 'State-of-the-Art of Establishing Test Procedures for Real Driving Gaseous Emissions from Light- and Heavy-Duty Vehicles', Energies, vol. 14, no. 14, pp. 4195-4195.
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Air pollution caused by vehicle emissions has raised serious public health concerns. Vehicle emissions generally depend on many factors, such as the nature of the vehicle, driving style, traffic conditions, emission control technologies, and operational conditions. Concerns about the certification cycles used by various regulatory authorities are growing due to the difference in emission during certification procedure and Real Driving Emissions (RDE). Under laboratory conditions, certification tests are performed in a ‘chassis dynamometer’ for light-duty vehicles (LDVs) and an ‘engine dynamometer’ for heavy-duty vehicles (HDVs). As a result, the test drive cycles used to measure the automotive emissions do not correctly reflect the vehicle’s real-world driving pattern. Consequently, the RDE regulation is being phased in to reduce the disparity between type approval and vehicle’s real-world emissions. According to this review, different variables such as traffic signals, driving dynamics, congestions, altitude, ambient temperature, and so on have a major influence on actual driving pollution. Aside from that, cold-start and hot-start have been shown to have an effect on on-road pollution. Contrary to common opinion, new technology such as start-stop systems boost automotive emissions rather than decreasing them owing to unfavourable conditions from the point of view of exhaust emissions and exhaust after-treatment systems. In addition, the driving dynamics are not represented in the current laboratory-based test procedures. As a result, it is critical to establish an on-road testing protocol to obtain a true representation of vehicular emissions and reduce emissions to a standard level. The incorporation of RDE clauses into certification procedures would have a positive impact on global air quality.
Rahman, SMA, Rizwanul Fattah, IM, Ong, HC & Zamri, MFMA 2021, 'State-of-the-Art of Strategies to Reduce Exhaust Emissions from Diesel Engine Vehicles', Energies, vol. 14, no. 6, pp. 1766-1766.
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Compression ignition engines play a significant role in the development of a country. They are widely used due to their innate properties such as high efficiency, high power output, and durability. However, they are considered one of the key contributors to transport-related emission and have recently been identified as carcinogenic. Thus, it is important to modify the designs and processes before, during, and after combustion to reduce the emissions to meet the strict emission regulations. The paper discusses the pros and cons of different strategies to reduce emissions of a diesel engine. An overview of various techniques to modify the pre-combustion engine design aspects has been discussed first. After that, fuel modifications techniques during combustion to improve the fuel properties to reduce the engine-out emission is discussed. Finally, post-combustion after-treatment devices are briefly discussed, which help improve the air quality of our environment.
Rasal, AS, Yadav, S, Yadav, A, Kashale, AA, Manjunatha, ST, Altaee, A & Chang, J-Y 2021, 'Carbon Quantum Dots for Energy Applications: A Review', ACS Applied Nano Materials, vol. 4, no. 7, pp. 6515-6541.
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Rasouli, H & Fatahi, B 2021, 'Geosynthetics reinforced interposed layer to protect structures on deep foundations against strike-slip fault rupture', Geotextiles and Geomembranes, vol. 49, no. 3, pp. 722-736.
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In the present study, the interaction mechanism of a 10-story moment-resisting building frame sitting on the conventional piled raft foundation with a strike-slip fault rupture with a dip angle of 90̊ is studied via three-dimensional finite element numerical simulation using ABAQUS. In addition, an alternative composite foundation system with geosynthetics reinforced interposed layer between piles and raft is proposed to improve the safety and performance of foundation under strike-slip fault ruptures. The interposed layer is reinforced with two high tensile strength of the geotextile layer. The inelastic behaviour of piles under large ground deformations is simulated using moment-curvature relationships of the real reinforced concrete section of piles and ductility concepts. The performance of both composite and conventional piled raft foundations are evaluated in terms of the geotechnical and structural responses of foundations including rotational and translational displacements and shear forces of the raft, as well as shear forces and ductility capacity of piles. The obtained results show the superior performance of composite foundation with geotextile reinforced interposed layer in terms of a significant reduction in shear forces in the raft and piles, as well as ductility demand in the piles.
Raza, Y, Raza, H, Ahmad, A, Quazi, MM, Abid, M, Kazmi, MR, Rahman, SMA, Zulfattah, ZM & Fattah, IMR 2021, 'Production and investigation of mechanical properties of graphene/polystyrene nano composites', Journal of Polymer Research, vol. 28, no. 6, pp. 1-12.
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Working with pristine polystyrene is a great challenge due to its poor mechanical properties and is a massive task to utilize for packaging and structural applications. This study includes the analysis and optimization of tensile properties of graphene-polystyrene nanocomposites membrane to determine the reinforcing effect of nanofiller on tensile properties. The two-dimensional (2D) graphene sheets and samples of graphene-polystyrene nanocomposites were fabricated by liquid exfoliation and solution casting technique, respectively. Nanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and thermogravimetric analysis (TGA) to evaluate their morphology, crystallographic phases, topography and thermal stability, respectively. Effect of filler concentration (0.06—0.74 wt. %), sonication time after mixing (3.18 – 36.82 min) and sonication temperature (16.48 – 58.52 ˚C) on ultimate tensile strength (UTS), percentage elongation and elastic modulus (E) were investigated and their responsive behavior was monitored respectively. In our experiment, it is shown that the concentration of graphene is a highly significant parameter. The optimized variables were found to be 0.60 wt. % of Graphene at 10 min of sonication time after mixing and 25 °C of sonication temperature. The obtained results demonstrate that the incorporation of graphene in the polystyrene matrix increases the mechanical properties of polystyrene. When compared with pristine polystyrene, the maximum increase witnessed in UTS, elongation and E was 97.36%, 82.70% and 174.08%, respectively.
Razzaq, L, Mujtaba, MA, Soudagar, MEM, Ahmed, W, Fayaz, H, Bashir, S, Fattah, IMR, Ong, HC, Shahapurkar, K, Afzal, A, Wageh, S, Al-Ghamdi, A, Ali, MS & EL-Seesy, AI 2021, 'Engine performance and emission characteristics of palm biodiesel blends with graphene oxide nanoplatelets and dimethyl carbonate additives', Journal of Environmental Management, vol. 282, pp. 111917-111917.
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This study investigated the engine performance and emission characteristics of biodiesel blends with combined Graphene oxide nanoplatelets (GNPs) and 10% v/v dimethyl carbonate (DMC) as fuel additives as well as analysed the tribological characteristics of those blends. 10% by volume DMC was mixed with 30% palm oil biodiesel blends with diesel. Three different concentrations (40, 80 and 120 ppm) of GNPs were added to these blends via the ultrasonication process to prepare the nanofuels. Sodium dodecyl sulphate (SDS) surfactant was added to improve the stability of these blends. GNPs were characterised using Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR), while the viscosity of nanofuels was investigated by rheometer. UV-spectrometry was used to determine the stability of these nanoplatelets. A ratio of 1:4 GNP: SDS was found to produce maximum stability in biodiesel. Performance and emissions characteristics of these nanofuels have been investigated in a four-stroke compression ignition engine. The maximum reduction in BSFC of 5.05% and the maximum BTE of 22.80% was for B30GNP40DMC10 compared to all other tested blends. A reduction in HC (25%) and CO (4.41%) were observed for B30DMC10, while a reduction in NOx of 3.65% was observed for B30GNP40DMC10. The diesel-biodiesel fuel blends with the addition of GNP exhibited a promising reduction in the average coefficient of friction 15.05%, 8.68% and 3.61% for 120, 80 and 40 ppm concentrations compared to B30. Thus, combined GNP and DMC showed excellent potential for utilisation in diesel engine operation.
Ren, J, Hao, D, Jiang, J, Phuntsho, S, Freguia, S, Ni, B-J, Dai, P, Guan, J & Shon, HK 2021, 'Fertiliser recovery from source-separated urine via membrane bioreactor and heat localized solar evaporation', Water Research, vol. 207, pp. 117810-117810.
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Urine with its abundant macronutrients (N-P-K) is an ideal resource for the production of fertiliser. However, the odor and pathogens in the raw urine must be removed to meet the public acceptance of urine collection systems and to enable its safe reuse as a fertiliser. In this work, real urine was collected and treated through a pilot-scale gravity-driven membrane bioreactor (GDMBR) to remove the malodorous organics and to nitrify almost 50% of the ammonia into nitrate. The stablised urine was subsequently distilled via low-cost heat localized solar evaporation (HLSE) to produce a non-odorous solid fertiliser. The developed HLSE with a small footprint can attract bulk solution into a vertical insulated space and quickly heat it up to 68 °C within 1 h. The HLSE process had vapour flux at 1.3 kg m-2 h-1 as well as high solar to vapour conversion efficiency at 87%. Based on the EDX mapping and XRD analysis, the generated crystals are mainly NaNO3, NH4Cl, NaCl, NH4H2PO4 and K2HPO4, which are ideal nutrients for vegetation. In this study, the produced urine-derived fertilisers have a better performance on the growth of the leafy basil than the all-purpose commercial fertilisers. Generally, the GDMBR-HLSE is a promising cost-effective and green technology for nutrients recovery from urine.
Ren, L, Wang, G, Huang, Y, Guo, J, Li, C, Jia, Y, Chen, S, Zhou, JL & Hu, H 2021, 'Phthalic acid esters degradation by a novel marine bacterial strain Mycolicibacterium phocaicum RL-HY01: Characterization, metabolic pathway and bioaugmentation', Science of The Total Environment, vol. 791, pp. 148303-148303.
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Phthalic acid esters (PAEs) are one of the most widely used plasticizers and the well-studied environmental pollutants with endocrine disrupting properties. Investigation about PAEs in terrestrial ecosystem has been extensively conducted while the fate of PAEs in marine environment remains underexplored. In this study, a novel di-(2-ethylhexyl) phthalate (DEHP) degrading marine bacterial strain, Mycolicibacterium phocaicum RL-HY01, was isolated and characterized from intertidal sediments. Strain RL-HY01 could utilize a range of PAE plasticizers as sole carbon source for growth. The effects of different environmental factors on the degradation of PAEs were evaluated and the results indicated that strain RL-HY01 could efficiently degrade PAEs under a wide range of pH (5.0 to 9.0), temperature (20 °C to 40 °C) and salinity (below 10%). Specifically, when Tween-80 was added as solubilizing agent, strain RL-HY01 could rapidly degrade DEHP and achieve complete degradation of DEHP (50 mg/L) in 48 h. The kinetics of DEHP degradation by RL-HY01 were well fitted with the modified Gompertz model. The metabolic intermediates of DEHP by strain RL-HY01 were identified by ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis and then the metabolic pathway of DEHP was deduced. DEHP was transformed into di-ethyl phthalate (DEP) via β-oxidation and then DEP was hydrolyzed into phthalic acid (PA) by de-esterification. PA was further transformed into gentisate via salicylic acid and further utilized for cell growth. Bioaugmentation of strain RL-HY01 with marine samples was performed to evaluate its application potential and the results suggested that strain RL-HY01 could accelerate the elimination of DEHP in marine samples. The results have advanced our understanding of the fate of PAEs in marine ecosystem and identified an efficient bioremediation strategy for PAEs-polluted marine sites.
Ren, Z, Zhang, X, Li, H-W, Huang, Z, Hu, J, Gao, M, Pan, H & Liu, Y 2021, 'Titanium Hydride Nanoplates Enable 5 wt% of Reversible Hydrogen Storage by Sodium Alanate below 80°C', Research, vol. 2021, pp. 9819176-13.
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Sodium alanate (NaAlH 4 ) with 5.6 wt% of hydrogen capacity suffers seriously from the sluggish kinetics for reversible hydrogen storage. Ti-based dopants such as TiCl 4 , TiCl 3 , TiF 3 , and TiO 2 are prominent in enhancing the dehydrogenation kinetics and hence reducing the operation temperature. The tradeoff, however, is a considerable decrease of the reversible hydrogen capacity, which largely lowers the practical value of NaAlH 4 . Here, we successfully synthesized a new Ti-dopant, i.e., TiH 2 as nanoplates with ~50 nm in lateral size and ~15 nm in thickness by an ultrasound-driven metathesis reaction between TiCl 4 and LiH in THF with graphene as supports (denoted as NP-TiH 2 @G). Doping of 7 wt% NP-TiH 2 @G enables a full dehydrogenation of NaAlH 4 at 80°C and rehydrogenation at 30°C under 100 atm H 2 with a reversible hydrogen capacity of 5 wt%, superior to all literature results reported so far. This indicates that nanostructured TiH 2 is much more effective than Ti-dopants in improving the hydrogen storage performance of NaAlH 4 . Our finding not only pushes the practical application of NaAlH 4 forward greatly but also opens up new opportunities to tailor the kinetics with the minimal capacity loss.
Rene, ER, Bui, XT, Ngo, HH, Nghiem, LD & Guo, W 2021, 'Green technologies for sustainable environment: an introduction', Environmental Science and Pollution Research, vol. 28, no. 45, pp. 63437-63439.
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Reza, MS, Mannan, M, Wali, SB, Hannan, MA, Jern, KP, Rahman, SA, Muttaqi, KM & Mahlia, TMI 2021, 'Energy storage integration towards achieving grid decarbonization: A bibliometric analysis and future directions', Journal of Energy Storage, vol. 41, pp. 102855-102855.
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During the last decade, numerous important benefits have been considered in energy storage development as a form of grid decarbonization that has enhanced a great impact on innovation, investigation, and further developments for emerging energy storage technologies. In this article, a comprehensive overview and investigation have been provided in the field of energy storage to achieve grid decarbonization. Related articles on energy storage integration were searched on the Scopus database under some defined conditions for the selection of the hot articles in this field. Most of the articles were published in 2018s (20) and the country of origin of the largest number of papers in Germany (19). The most profile authors were from 3 different countries of origin (seven of them from Germany) and 5 different institutions, which published 35 articles. This study identified that energy storage integration as a form of achieving grid decarbonization has offered great insights into the advancement and development in this research area. In this study, grid conned energy storage was determined based on evidence through bibliometric analysis to identify the most influential articles, journals, and countries in the field, mapping the interdisciplinary character, visualizing nature and trends, and synthesizing areas for further research. It is estimated that selecting, developing, and investigating the highest cited papers and its analysis will contribute to a systematic basis for future advancement of energy storage integration and suggest promising avenues for further research towards achieving grid decarbonization.
Riayatsyah, TMI, Thaib, R, Silitonga, AS, Milano, J, Shamsuddin, AH, Sebayang, AH, Rahmawaty, Sutrisno, J & Mahlia, TMI 2021, 'Biodiesel Production from Reutealis trisperma Oil Using Conventional and Ultrasonication through Esterification and Transesterification', Sustainability, vol. 13, no. 6, pp. 3350-3350.
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The limitation of fossil fuel sources and negative environmental impact persuade scientists around the world to find a solution. One possible solution is by using renewable fuel to replace fossil fuel with an inexpensive, fast, and effective production process. The objective of this study is to investigate the biodiesel production from crude Reutealis trisperma oil using the conventional and the ultrasonic bath stirrer method through the esterification and transesterification process. The result shows that the most effective reaction time with an optimum condition for the esterification and transesterification of Reutealis trisperma oil is at 2 h 30 min by using the ultrasonic bath stirrer method. The optimum conditions at a temperature of 55 °C for the esterification and at 60 °C for transesterification with 2% (v/v) of sulphuric acid with catalyst concentration of 0.5 wt.% were a methanol-to-oil ratio of 60%, and agitation speed of 1000 rpm. This optimum condition gives the highest yield of 95.29% for the Reutealis trisperma biodiesel. The results showed that the ultrasonic bath stirrer method had more effect on the reaction time needed than using the conventional method and reduced half of the conventional method reaction time. Finally, the properties of Reutealis trisperma biodiesel fulfilled the ASTM D6751 and EN 14214 biodiesel standards with density, 892 kg/m3; pour point, −2 °C; cloud point, −1 °C; flash point, 206.5 °C; calorific value, 40.098 MJ/kg; and acid value, 0.26 mg KOH/g.
Rizal, TA, Amin, M, Widodo, SB, Abdul Rachman, N, Amir, F, Pane, N & Mahlia, TMI 2021, 'Integration of Phase Change Material in the Design of Solar Concentrator-Based Water Heating System', Entropy, vol. 24, no. 1, pp. 57-57.
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Indonesia has been blessed with excellent solar heat distribution, which can be used as renewable energy to heat water. Various technologies have been developed to utilize these inexhaustible thermodynamic resources, in the form of photons arrays, converted into concentrated heat for daily use, i.e., solar water heater. This renewable-based water heating system can provide significant energy efficiency, benefit the environment, and reduce energy use costs. This experimental study attempts to harvest the energy from the sun using a cylindrical through collector (CTC) type solar concentrator. The CTC was made of the solar reflective film (SRF) affixed to concentrator collector surfaces which was then mounted on an adjustable angle frame of the concentrator collector support. The heat generated from the concentrator was stored in water, and phase change material is embedded in the system to retain the heat longer. The research was carried out in Langsa City, Aceh, Indonesia. The results showed that water heaters using CTC systems could produce 16 L of hot water retained at 40–60 °C for four hours. With the addition of beeswax, the water temperature of the same capacity can be maintained at 40–60 °C for around 5 h. This technology demonstrated an excellent result that produces as much as 60 L of water per day, increasing solar thermal energy efficiency. This technology presented a great potential for replication or even for further development on an industrial scale.
Roslan, MF, Hannan, MA, Jern Ker, P, Begum, RA, Indra Mahlia, TM & Dong, ZY 2021, 'Scheduling controller for microgrids energy management system using optimization algorithm in achieving cost saving and emission reduction', Applied Energy, vol. 292, pp. 116883-116883.
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This study deals with the development of an optimal power scheduling controller for energy management of distributed energy resources in the microgrid system. The developed optimized controller is implemented using lightning search algorithm to overcome the uncertainties of microgrid energy management and to provide an optimum power delivery to loads with minimum cost. The primary objectives of the proposed optimized controller are to: (i) develop an optimized controller for microgrids energy management, (ii) minimize the total operating cost of the distributed energy resources units, (iii) reduce the environmental emission, and (iv) solve the complicated constraint optimization problems. The proposed optimization algorithm is implemented in the modified IEEE 14-bus test system to optimize the microgrid power management schedule. The optimized controller is executed based on the real load varying conditions recorded in Perlis, Malaysia. It is observed that the optimized controller successfully reduced the amount of power consumption from 971.65 MW to 364.3 MW which in turn saving cost of RM 265432.06. The proposed scheduling optimized controller performance is compared with the recent reported work of backtracking search algorithm optimization for validation. Result shows that the lightning search algorithm based MG controller produced a cost-effective system with 62.5% of cost saving and 61.98% of carbon dioxide emission reduction which is much higher compared to with MG and backtracking search algorithm based MG optimization, respectively. The effectiveness of the proposed approach outperformed other techniques in terms of minimum total operating cost of distributed energy resources and solving complicated constraints in optimization problems.
Roslan, MF, Hannan, MA, Ker, PJ, Muttaqi, KM & Mahlia, TMI 2021, 'Optimization algorithms for energy storage integrated microgrid performance enhancement', Journal of Energy Storage, vol. 43, pp. 103182-103182.
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Distributed energy resource (DER) in microgrid has emerged significant challenges in the existing centralized energy management systems. This is due to the stochastic energy sources integrated into microgrid and dynamic power demand that has brought difficulties in controlling the optimal output power. An inefficient and without optimally controlled DERs and charge/discharge of energy storage system results in high operating cost to consumers as well as decrease a lifetime of energy storage based microgrid. Therefore, to solve the issues, a day-ahead optimized scheduling controller-based novel lightning search algorithm (LSA) technique is introduced to provide an optimum power delivery with minimum cost including optimum use of energy storage. The main objective of the proposed controller is to develop an optimized controller for the microgrid to minimize the operating cost of DER and optimal operation of charge/discharge of the energy storage system. The optimized controller's effectiveness is executed in a 14-bus test system based on a real load varying conditions recorded in Perlis, Malaysia for 24-hours’ operation. The obtained results show that the performance of the optimized controller for energy storage-based microgrid successfully reduced the amount of power consumption which in turn saving the energy and cost of 62.5%. The proposed day-ahead optimized scheduling controller outperforms the backtracking search algorithm and particle swarm optimization techniques in terms of iteration (53.56) and time consumption (2915.2 min) which in turn validate the controller performance. Thus, the developed optimized controller can realize the effectiveness of energy storage integrated MG energy management with the optimum operation of DER units.
Ryu, S, Fonseka, C, Naidu, G, Loganathan, P, Moon, H, Kandasamy, J & Vigneswaran, S 2021, 'Recovery of rare earth elements (Lu, Y) by adsorption using functionalized SBA-15 and MIL-101 (Cr)', Chemosphere, vol. 281, pp. 130869-130869.
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Due to increasing application in the green energy sector, rare earth elements (REEs) have become a precious commodity in the international market. The REEs, Yttrium (Y) and Lutetium (Lu) are used as catalysts in wide array of industries. SBA-15 modified with 1,4-phthaloyl diamido-propyltriethoxysilane (1,4-PA-APTES) ligands; and chromium based metal organic frameworks (MOF) modified with PMIDA (MIL-101-PMIDA) were prepared in this study as potential adsorbents for recovery of these elements. The adsorption capacities for Lu and Y on virgin SBA-15 were negligible. After modification of SBA-15, the Langmuir adsorption capacities for Lu and Y significantly increased to 17.0 and 17.9 mg/L, respectively. The Langmuir adsorption capacities of Lu and Y on PMIDA modified MIL-101 (MIL-101-PMIDA) were 63.4 and 25.3 mg/g, respectively. Higher adsorption capacities of the MOF are due to its higher surface area (1050 m2/g) and beneficial functional groups such as phosphonic group present on the adsorbent surface and it attributes to rapider REE adsorption on MIL-101-PMIDA than on1,4-PA-SBA. Lu adsorption capacity was 2.5 times higher than Y due to its superior ion-exchange capability with grafted phosphonic groups. Both adsorbents retained over 90% of adsorption capacity after 5 adsorption/desorption cycles which demonstrate the high structural stability of the materials.
Ryu, S, Naidu, G, Moon, H & Vigneswaran, S 2021, 'Continuous and selective copper recovery by multi-modified and granulated SBA-15', Chemosphere, vol. 271, pp. 129820-129820.
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Continuous and selective recovery of copper (Cu) from heavy metal wastewater not only mitigates the pollution of environment but also can be applied for industrial field. Due to several advantages such as large pore size, easy modification, physical and chemical stabilities, mesoporous silica material, SBA-15, has been synthesized via hydrothermal reaction in this study. For enhancing the adsorption capacity and selectivity for Cu ions, prepared SBA-15 was modified with manganese loading and amine-grafting (MN-SBA) then granulated by alginic-acid (GMN-SBA), successfully. Adsorption capacities for heavy metals such as Cu, Zn, Ni and Mn were 2.11, 1.24, 1.74 and 1.25 mmol/g on MN-SBA and decreased to 1.23, 0.68, 0.86 and 0.65 when it was granulated. Even though the adsorption capacities of GMN-SBA for heavy metals decreased by 40–50%, it enabled easy regeneration and separation process when applied for continuous fixed-bed column adsorption mode. Specifically, the results demonstrated that GMN-SBA was able to be reused for 5 times while maintaining over 80% adsorption capacities. Fixed-bed adsorption results were well explained by dynamic adsorption model incorporated with linear driving force approximation (LDFA) model. The simulation of fixed-bed adsorption tests was proceeded in terms of bed length, feeding concentration and flow rate, and it showed the breakthrough times were shifted in the axis of time. In multi-component adsorption, LDFA model showed a high overshoot phenomenon of the breakthrough curves for Zn, Ni and Mn compared to Cu. This reflected the high affinity of Cu towards GMN-SBA compared to other heavy metals.
Salaheldeen, M, Mariod, AA, Aroua, MK, Rahman, SMA, Soudagar, MEM & Fattah, IMR 2021, 'Current State and Perspectives on Transesterification of Triglycerides for Biodiesel Production', Catalysts, vol. 11, no. 9, pp. 1121-1121.
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Triglycerides are the main constituents of lipids, which are the fatty acids of glycerol. Natural organic triglycerides (viz. virgin vegetable oils, recycled cooking oils, and animal fats) are the main sources for biodiesel production. Biodiesel (mono alkyl esters) is the most attractive alternative fuel to diesel, with numerous environmental advantages over petroleum-based fuel. The most practicable method for converting triglycerides to biodiesel with viscosities comparable to diesel fuel is transesterification. Previous research has proven that biodiesel–diesel blends can operate the compression ignition engine without the need for significant modifications. However, the commercialization of biodiesel is still limited due to the high cost of production. In this sense, the transesterification route is a crucial factor in determining the total cost of biodiesel production. Homogenous base-catalyzed transesterification, industrially, is the conventional method to produce biodiesel. However, this method suffers from limitations both environmentally and economically. Although there are review articles on transesterification, most of them focus on a specific type of transesterification process and hence do not provide a comprehensive picture. This paper reviews the latest progress in research on all facets of transesterification technology from reports published by highly-rated scientific journals in the last two decades. The review focuses on the suggested modifications to the conventional method and the most promising innovative technologies. The potentiality of each technology to produce biodiesel from low-quality feedstock is also discussed.
Samadi, A, Xie, M, Li, J, Shon, H, Zheng, C & Zhao, S 2021, 'Polyaniline-based adsorbents for aqueous pollutants removal: A review', Chemical Engineering Journal, vol. 418, pp. 129425-129425.
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Samadi-Boroujeni, H, Naghshbandi, SA & Altaee, A 2021, 'Time Variations of Sediment Floc Size and Density by using Settling Column Data', Civil Engineering Research Journal, vol. 11, no. 3, pp. 1-12.
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The current study was conducted to examine the sediment floc size and density changes over time in quiescent water by experimenting with a plexy glass settling column. The experiments were done with 5 initial concentrations of 3, 5, 10, 15 and 20 g/l and suspended sediment concentration was measured at different time and height intervals. Mclauglin differential equation, Kranenburg’s equation, and Stokes’ Law relationship were solved to estimate the geometrical characteristics of the flocs. In all experiments, the maximum settling velocity of particles occurred 15 minutes after the beginning of the settling process and the maximum settling velocity of sediments was obtained about 8 times the average settling velocity. The results showed that after 15 minutes of the start of the experiment, the floc size and density reached to the maximum and minimum value, respectively.
Samani, BH, Behruzian, M, Najafi, G, Fayyazi, E, Ghobadian, B, Behruzian, A, Mofijur, M, Mazlan, M & Yue, J 2021, 'The rotor-stator type hydrodynamic cavitation reactor approach for enhanced biodiesel fuel production', Fuel, vol. 283, pp. 118821-118821.
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Today renewable energies such as biodiesel have considerable role in the bio-based economy. Long production time and low efficiency are a number of problems in biodiesel production that is essential to be considered when designing and operating the biodiesel production systems. In this study, using safflower oil in a hydrodynamic cavity reactor, biodiesel fuel was produced in the possible shortest time and maximum efficiency. The effect of reaction time (30, 60 and 90 s), concentration of potassium hydroxide catalyst (0.75%, 1% and 1.25%), alcohol to oil ratio (6, 8 and 10) and rotor-stator distance (1 cm, 2 cm and 3 cm) on the reaction yield were analyzed. The results were analyzed by response surface methodology. Among the independent variables, reaction time was the most important factor on the reaction yield, which had a positive impact on the quality of methyl ester. The optimum values obtained were: 63.88 s reaction time, 0.94% catalyst concentration, 1: 8.36 alcohol to oil molar ratio, 1.53 cm rotor-stator distance, and 89.11% yield. Several properties and compounds of biodiesel obtained were measured and compared with ASTM D6751 (American Society for Testing and Materials) and EN 14214 standard (European Standards). The results showed that most of the features conform to the afore-mentioned standard. Therefore, transesterification of safflower oil with a hydrodynamic cavitation reactor can function as a good alternative to the diesel.
Sandhya, M, Ramasamy, D, Sudhakar, K, Kadirgama, K, Samykano, M, Harun, WSW, Najafi, G, Mofijur, M & Mazlan, M 2021, 'A systematic review on graphene-based nanofluids application in renewable energy systems: Preparation, characterization, and thermophysical properties', Sustainable Energy Technologies and Assessments, vol. 44, pp. 101058-101058.
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Graphene has attracted much attention from various researchers because of its enhanced mechanical, thermal, and physio-chemical properties. Graphene exhibits high thermal conductivity and stability, less erosion and corrosion than other available nanoparticles. Various existing literature signifies a large portion of the research focuses on stability, heat transfer characteristics and thermal conductivity of Graphene nanofluids. This review article represents a detailed analysis of the preparation techniques, characterization methods stability evaluation, and thermal properties enhancements of Graphene nanofluids. Comparative analysis of the effects of nanoparticle size, volume concentration and temperature on thermal conductivity and viscosity of Graphene nanofluids are reviewed based on heat transfer application. Graphene nanoparticles significantly enhances the thermal conductivity, viscosity, and heat transfer capacity of base fluid. It is noticed that the thermal conductivity of Graphene nanofluids increases with an increase in temperature and volume concentration. Applications of Graphene based nano coolant in automotive radiator, electronic cooling, solar cells and fuel cells are presented. This article can be the rapid reference model with investigational and theoretical analysis for highly critical considerations that impact the thermal performance of graphene based nanofluids in different heat transfer trends. This review also outlined the imminent challenges and future scope of research in Graphene.
Satya, A, Harimawan, A, Haryani, GS, Johir, MAH, Vigneswaran, S, Kurniawan, TA & Setiadi, T 2021, 'Integrated treatment of submerged membrane and adsorption using dried Aphanothece sp for removing cadmium from synthetic wastewater', Journal of Water Process Engineering, vol. 41, pp. 102022-102022.
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Water pollution from the discharge of wastewater containing toxic heavy metals such as cadmium (Cd) to the natural water bodies is one of the biggest problem affecting humanity. Different technologies such as sorption, membrane filtration etc. have been used to remove heavy metal from the polluted water. In this work, the effects of operational parameters on the ability of the submerged membrane adsorption hybrid system (SMAHS) to remove Cd2+ from synthetic wastewater using dried Aphanothece sp A15 as a suspended biosorbent was evaluated. This biomass originates from a cyanobacterium was cultivated in a photobioreactor system enriched with 15 % of CO2. The operational parameters investigated were filtration flux, biomass dosage, frequency of replacing biosorbent, and initial metal concentration. Of the various parameters, the filtration flux and the initial concentration of Cd were the most influential parameters concerning biosorption efficiency in this study. More than 95 % removal of Cd was achieved with initial Cd concentration of 4.89 mg/L at a filtration flux of 20 L/m2.h. The highest biosorption capacity (112.89 mg/g) was obtained with a flux of 60 L/m2.h.The biosorbent became saturated after 20 h of operation without biosorbent replacement. This suggests that the dried biomass of Aphanothece sp A15 has the potential to be implemented in the industrial wastewater treatment plant using SMAHS processes integrated within the CO2 bio-sequestration unit. Therefore, cadmium removal from wastewater can be coupled with the reduction of CO2 emissions from flue gas.
Satya, A, Harimawan, A, Sri Haryani, G, Johir, MAH, Nguyen, LN, Nghiem, LD, Vigneswaran, S, Ngo, HH & Setiadi, T 2021, 'Fixed-bed adsorption performance and empirical modelingof cadmium removal using adsorbent prepared from the cyanobacterium Aphanothece sp cultivar', Environmental Technology & Innovation, vol. 21, pp. 101194-101194.
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© 2020 Elsevier B.V. Water contamination by cadmium (Cd), which is a toxic heavy metal widely used in many industrial processes, is a pervasive environmental problem. This study investigated the removal of Cd by dry cyanobacterium Aphanothece sp cultivar in adsorption columns The effect of inlet Cd concentrations (1.00 – 4.85mg/L), flow rates (0.30-0.60 L/h) and bed height (4.6 -7.2 cm) on the breakthrough characteristics of the adsorption column was investigated. The maximum adsorption capacity and efficiency were found to be 8.20 mg/g and 89.07 %, respectively with a flow rate of 0.60 L/h and 4.85 mg/L inlet concentration of Cd. The fixed bed adsorption data were fitted to three well known fixed bed empirical models namely Thomas, Adam–Bohart and Yoon–Nelson. The experimental results well fitted with the models mentioned above with R2 of greater than 0.98 at different conditions. The regeneration efficiency of benthic cyanobacterium Aphanothece sp cultivar based adsorbent was studied using 0.1 M HCl. Repetitive adsorption–regeneration experiment show that, at the end of the fifth cycle, the desorption efficiency decreased by 21%. Thus, further research is necessary to improve the reusability of dried biomass of cyanobacterium Aphanothece sp adsorbent.
Seo, DH, Xie, M, Murdock, AT, van der Laan, T, Lawn, M, Park, MJ, Woo, YC, Pineda, S, Hong, JM, Grigore, M, Yick, S, Han, Z, Millar, G, Gray, S, Ostrikov, K, Shon, HK & Bendavid, A 2021, 'Rejection of harsh pH saline solutions using graphene membranes', Carbon, vol. 171, pp. 240-247.
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Water security is a pressing issue for global citizens in the 21st century. Concerns over clean water supply, and the environmental impact of industrial waste water, make water treatment a world-wide problem requiring a simple and effective solution. Membrane distillation is an emerging water purification technique that complements state-of-the-art reverse osmosis processes. Membrane distillation achieves high rejection over a range of salt concentrations while maintaining flux, using a temperature differential as opposed to pressure across the membrane. Importantly the process can be driven using low grade waste heat energy. Current membranes used in membrane distillation do not guarantee stable membrane performance under harsh (high salt and acid or base concentrations) conditions. Here we report, a permeable graphene membrane operating in harsh conditions with no observable degradation. A permeate of pH neutral water with a flux of 25 ± 1 L m−2 h−1 is produced by this membrane through near (99.9 ± 0.1%) ion rejection from 0.6 M sodium chloride at pH 1 and pH 13, over 144 h. More complex ion solutions, including real acid mine drainage waste-water, were also successfully purified. These findings may present a membrane that is suitable to improve water supply and reduce the environmental impact of industrial waste-water.
Shafaghat, A, Khabbaz, H & Fatahi, B 2021, 'Analytical and Numerical Approaches to Attain the Optimum Tapering Angle for Axially-Loaded Bored Piles in Sandy Soils', International Journal of Geomechanics, vol. 21, no. 7.
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This study aims to establish an equation to obtain the optimum tapering angle (αopt) for bored tapered piles that is correlated with pile geometry and sand properties that vary with the relative density. This αopt corresponds with the maximum axial bearing capacity when the volume of material in the tapered pile is maintained identical to the counterpart straight cylindrical pile. First, analytical formulations will be developed to estimate the axial bearing capacity of bored tapered piles that are embedded in sand. The proposed governing equations capture the shaft vertical bearing component of the tapered pile, which is unique to tapered piles and varies nonlinearly with the tapering angle (α). By differentiating the obtained bearing capacity equation for α, an αopt is achieved. The finite element method (FEM) will be adopted to conduct the numerical modeling and to calibrate the model parameters of the proposed analytical equation, which considers soil nonlinearities and interactions between the tapered pile and the surrounding soil that is subjected to axial loading. The UBCSAND constitutive model will be used to simulate the soil response near the tapered pile and the model parameters will be calibrated against laboratory test results for sandy soils with different relative densities. However, due to the complexity of the proposed differentiation and inverse calculation, a numerical solution will be used to obtain the results. Then, the load-displacement curves of the tapered piles will be attained numerically and αopt, which results in the maximum axial capacity of the pile, will be determined. The results exhibit good agreement between the analytically determined axial bearing capacity for the tapered pile and the corresponding numerical modeling predictions. Furthermore, a simplified empirical equation will be established to select αopt, which could be used by practicing engineers.
Shahabuddin, M, Alim, MA, Alam, T, Mofijur, M, Ahmed, SF & Perkins, G 2021, 'A critical review on the development and challenges of concentrated solar power technologies', Sustainable Energy Technologies and Assessments, vol. 47, pp. 101434-101434.
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Solar energy is considered to be one of the most promising renewable and sustainable energy sources. Two key technologies such as photovoltaic and concentrated solar power are mainly used to convert solar radiation, out of which photovoltaic directly converts solar radiation into electricity, while concentrated solar power technology converts solar radiation both into heat and electricity. The key advantages of concentrated solar power technology over photovoltaic is its capability of storing heat energy which can be utilised in the absence of sunlight, overcoming the limitation of the intermittent nature of solar power. Currently, the cost for the concentrated solar power with storage is about 9.0 ¢/kWh (same as commercial photovoltaic system), which is expected to drop at ~5.0 ¢/kWh by 2030. Besides four mainstream concentrated solar power technologies, this paper reviewed the application of concentrated solar power in thermolysis, thermochemical cycle, hydrocarbon cracking, reforming and solar gasification. Based on the literature review, this study has outlined the key challenges and prospects of concentrated solar power technologies. The main challenge in thermolysis is the requirement of very high temperature, while the thermochemical cycle is inefficient. Solar thermal cracking, reforming, and gasification integrate carbonaceous fuel to produce synthesis gas and hydrogen and therefore are not emission-free. The concentrated solar power technologies require further development and cost reductions before they can be scaled up to have a meaningful impact on renewable energy targets towards 2050.
Shahabuddin, M, Mofijur, M, Shuvho, MBA, Chowdhury, MAK, Kalam, MA, Masjuki, HH & Chowdhury, MA 2021, 'A Study on the Corrosion Characteristics of Internal Combustion Engine Materials in Second-Generation Jatropha Curcas Biodiesel', Energies, vol. 14, no. 14, pp. 4352-4352.
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The corrosiveness of biodiesel affects the fuel processing infrastructure and different parts of an internal combustion (IC) engine. The present study investigates the corrosion behaviour of automotive materials such as stainless steel, aluminium, cast iron, and copper in 20% (B20) and 30% (B30) by volume second-generation Jatropha biodiesel using an immersion test. The results were compared with petro-diesel (B0). Various fuel properties such as the viscosity, density, water content, total acid number (TAN), and oxidation stability were investigated after the immersion test using ASTM D341, ASTM D975, ASTM D445, and ASTM D6751 standards. The morphology of the corroded materials was investigated using optical microscopy and scanning electron microscopy SEM), whereas the elemental analysis was carried out using energy-dispersive X-ray spectroscopy (EDS). The highest corrosion using biodiesel was detected in copper, while the lowest was detected in stainless steel. Using B20, the rate of corrosion in copper and stainless steel was 17% and 14% higher than when using diesel, which further increased to 206% and 86% using B30. After the immersion test, the viscosity, water content, and TAN of biodiesel were increased markedly compared to petro-diesel.
Shahapurkar, K, Chenrayan, V, Soudagar, MEM, Badruddin, IA, Shahapurkar, P, Elfasakhany, A, Mujtaba, MA, Siddiqui, MIH, Ali, MA & Mahlia, TMI 2021, 'Leverage of Environmental Pollutant Crump Rubber on the Dry Sliding Wear Response of Epoxy Composites', Polymers, vol. 13, no. 17, pp. 2894-2894.
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The effect of crump rubber on the dry sliding wear behavior of epoxy composites is investigated in the present study. Wear tests are carried out for three levels of crump rubber (10, 20, and 30 vol.%), normal applied load (30, 40, and 50 N), and sliding distance (1, 3, and 5 km). The wear behavior of crump rubber–epoxy composites is investigated against EN31 steel discs. The hybrid mathematical approach of Taguchi-coupled Grey Relational Analysis (GRA)—Principal Component Analysis (PCA) is used to examine the influence of crump rubber on the tribological response of composites. Mathematical and experimental results reveal that increasing crump rubber content reduces the wear rate of composites. Composites also show a significant decrease in specific wear values at higher applied loads. Furthermore, the coefficient of friction also shows a decreasing trend with an increase in crump rubber content, indicating the effectiveness of reinforcing crump rubber in a widely used epoxy matrix. Analysis of Variance (ANOVA) results also reveal that the crump rubber content in the composite is a significant parameter to influence the wear characteristic. The post-test temperature of discs increases with an increase in the applied load, while decreasing with an increase in filler loading. Worn surfaces are analyzed using scanning electron microscopy to understand structure–property correlations. Finally, existing studies available in the literature are compared with the wear data of the present study in the form of a property map.
Sharma, P, Ngo, HH, Khanal, S, Larroche, C, Kim, S-H & Pandey, A 2021, 'Efficiency of transporter genes and proteins in hyperaccumulator plants for metals tolerance in wastewater treatment: Sustainable technique for metal detoxification', Environmental Technology & Innovation, vol. 23, pp. 101725-101725.
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Sharma, P, Tripathi, S, Sirohi, R, Kim, SH, Ngo, HH & Pandey, A 2021, 'Uptake and mobilization of heavy metals through phytoremediation process from native plants species growing on complex pollutants: Antioxidant enzymes and photosynthetic pigments response', Environmental Technology & Innovation, vol. 23, pp. 101629-101629.
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Shen, L, Chen, H, Qi, C, Fu, Q, Xiong, Z, Sun, Y & Liu, Y 2021, 'A green and facile fabrication of rGO/FEVE nanocomposite coating for anti-corrosion application', Materials Chemistry and Physics, vol. 263, pp. 124382-124382.
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Shen, X, Zhang, J, Xie, H, Sun, B, Liang, S, Wu, H, Hu, Z, Ngo, HH, Guo, W & Lu, J 2021, 'Electron shuttles enhance phenanthrene removal in constructed wetlands filled with manganese oxides-coated sands', Chemical Engineering Journal, vol. 426, pp. 131755-131755.
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Mn oxides could realize persistent organic pollutants (POPs) removal through the cycle of Mn between Mn(II) and biogenic Mn oxides in constructed wetlands (CWs) filled with Mn oxides. However, the inefficient cycle of Mn caused by the limited oxidation ability of Mn oxides inhibited its effective degradation of POPs. Ruthenium (Ru) and 2,2′-azino-bis(3-ethylbenzothiazoline)-6-sulfonate (ABTS) could act as electron shuttles in catalytic Mn oxides oxidation process. In this study, phenanthrene (PHE) was selected as a typical POP and biochar (BC) supported Ru (Ru/BC) and ABTS (ABTS/BC) were induced in CWs with Mn oxides (birnessite). The removal efficiencies of PHE in CWs with Ru/BC and ABTS/BC reached 94.61% and 95.51%, higher than the control (79.91%). ABTS performed best for enhancing Mn cycle based on the results of highest oxidation removal capacity and relative abundance of Mn-oxidizing bacteria. What's more, the addition of Ru/BC contributed to the best adsorption ability and highest relative abundance of PHE degrading bacteria.
Shi, X, Wei, W, Wu, L & Ni, B-J 2021, 'Zero-valent iron mediated biological wastewater and sludge treatment', Chemical Engineering Journal, vol. 426, pp. 130821-130821.
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In quest of meeting the requirements of sustainable development, coupling zero valent iron (ZVI) with microorganisms has attracted extensive attentions for enhancing biological wastewater and sludge treatment in terms of microbial growth, nutrients removal, and resources recovery. Given to the significant role of ZVI playing in biological wastewater and sludge treatment, a thorough evaluation of the associated interactions among ZVI and microorganisms is necessary to further scale-up the application of ZVI-based biotechnologies. To this end, this review comprehensively summarizes the mechanisms of ZVI for enhancing nutrients removal (i.e., C, N, S and P) in several typical biological wastewater treatment processes, discusses the role of ZVI in improving the excess sludge reduction by dewatering or anaerobic digestion for methane production, and analyzes the feasibility of recovering phosphorus from anaerobic sludge digestion system in the form of vivianite through using ZVI. Knowledge gaps regarding the application of ZVI in sludge or wastewater treatment are also identified in this review to facilitate the further development of the ZVI-based biological technology.
Shindhal, T, Rakholiya, P, Varjani, S, Pandey, A, Ngo, HH, Guo, W, Ng, HY & Taherzadeh, MJ 2021, 'A critical review on advances in the practices and perspectives for the treatment of dye industry wastewater', Bioengineered, vol. 12, no. 1, pp. 70-87.
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Rapid industrialization has provided comforts to mankind but has also impacted the environment harmfully. There has been severe increase in the pollution due to several industries, in particular due to dye industry, which generate huge quantities of wastewater containing hazardous chemicals. Although tremendous developments have taken place for the treatment and management of such wastewater through chemical or biological processes, there is an emerging shift in the approach, with focus shifting on resource recovery from such wastewater and also their management in sustainable manner. This review article aims to present and discuss the most advanced and state-of-art technical and scientific developments about the treatment of dye industry wastewater, which include advanced oxidation process, membrane filtration technique, microbial technologies, bio-electrochemical degradation, photocatalytic degradation, etc. Among these technologies, microbial degradation seems highly promising for resource recovery and sustainability and has been discussed in detail as a promising approach. This paper also covers the challenges and future perspectives in this field.
Shon, HK, Jegatheesan, V, Shu, L & Phuntsho, S 2021, 'Challenges in Environmental Science and Engineering (CESE-2019)', Process Safety and Environmental Protection, vol. 148, pp. 1264-1267.
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Siddiki, SYA, Uddin, MN, Mofijur, M, Fattah, IMR, Ong, HC, Lam, SS, Kumar, PS & Ahmed, SF 2021, 'Theoretical calculation of biogas production and greenhouse gas emission reduction potential of livestock, poultry and slaughterhouse waste in Bangladesh', Journal of Environmental Chemical Engineering, vol. 9, no. 3, pp. 105204-105204.
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The utilisation of available renewable resources and mitigating their impact on the environment boosts sustainable development and helps to achieve the United Nations Sustainable Development Goals. Biogas is a renewable energy option produced through anaerobic digestion of wastes such as livestock excreta and slaughterhouse wastes. Biogas production is treated as one of the leading processes to combat climate change as well as a waste management strategy, especially for a developing country like Bangladesh. It is also vital in meeting future demand for energy utilising indigenous sources. Livestock farming is an important economic activity in rural areas of Bangladesh. Thus, the livestock waste production, estimated biogas generation capacity, electricity generation potential, greenhouse gas (GHG) reduction potential, and estimated biofertiliser generation capacity of Bangladesh were determined for the financial year 2018-2019 in this study. The results show that Bangladesh had 486.77 million tons per year of animal waste products to produce 27,923.72 million m3/year biogas in 2018-2019. This biogas potential corresponds to a theoretical potential to produce a 512 PJ/year heating value and electric power of 50 TW h/year. Besides, about 29.232 million tons per year of organic fertiliser can be produced with the residues of the biogas plants. The findings of this study will contribute to guiding policymakers and governments who will concentrate on the use of animal waste in biogas industries and livestock farming as a potential bioenergy source to meet national energy demand.
Siow, JH, Bilad, MR, Caesarendra, W, Leam, JJ, Bustam, MA, Sambudi, NS, Wibisono, Y & Mahlia, TMI 2021, 'Progress in Development of Nanostructured Manganese Oxide as Catalyst for Oxygen Reduction and Evolution Reaction', Energies, vol. 14, no. 19, pp. 6385-6385.
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The rise in energy consumption is largely driven by the growth of population. The supply of energy to meet that demand can be fulfilled by slowly introducing energy from renewable resources. The fluctuating nature of the renewable energy production (i.e., affected by weather such as wind, sun light, etc.), necessitates the increasing demand in developing electricity storage systems. Reliable energy storage system will also play immense roles to support activities related to the internet of things. In the past decades, metal-air batteries have attracted great attention and interest for their high theoretical capacity, environmental friendliness, and their low cost. However, one of the main challenges faced in metal-air batteries is the slow rate of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) that affects the charging and the discharging performance. Various types of nanostructure manganese oxide with high specific surface area and excellent catalytic properties have been synthesized and studied. This review provides a discussion of the recent developments of the nanostructure manganese oxide and their performance in oxygen reduction and oxygen evolution reactions in alkaline media. It includes the experimental work in the nanostructure of manganese oxide, but also the fundamental understanding of ORR and OER. A brief discussion on electrocatalyst kinetics including the measurement and criteria for the ORR and the OER is also included. Finally, recently reported nanostructure manganese oxide catalysts are also discussed.
Snyder, RL, Choo, Y, Gao, KW, Halat, DM, Abel, BA, Sundararaman, S, Prendergast, D, Reimer, JA, Balsara, NP & Coates, GW 2021, 'Improved Li+ Transport in Polyacetal Electrolytes: Conductivity and Current Fraction in a Series of Polymers', ACS Energy Letters, vol. 6, no. 5, pp. 1886-1891.
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Sohn, W, Guo, W, Ngo, HH, Deng, L & Cheng, D 2021, 'Powdered activated carbon addition for fouling control in anaerobic membrane bioreactor', Bioresource Technology Reports, vol. 15, pp. 100721-100721.
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The effect of powdered activated carbon (PAC) addition to a conventional anaerobic membrane bioreactor (AnMBR) on removal performance and membrane fouling was explored in this study. The optimal one-off PAC dose could increase average chemical oxygen demand (COD) and total organic carbon (TOC) removal rates up to 15.7% and 15.6%, respectively. The PAC addition exhibited not only lower TMP increase rate, but also reduced soluble microbial product (SMP) and extracellular polymeric substances (EPS). Higher protein to polysaccharide ratio of SMP and higher zeta potential in AnMBR with PAC could enhance hydrophobicity and flocculation ability, thereby effectively alleviating membrane fouling. Lower total membrane resistance and pore blocking resistance indicated that PAC addition could prevent both severe pore blocking and irreversible fouling, due to the lower polysaccharide level in SMP of the cake layer. Moreover, PAC addition facilitated the decrease in fouling-related bacteria such as Cloacibacterium and Paludibacter.
Sohn, W, Guo, W, Ngo, HH, Deng, L, Cheng, D & Zhang, X 2021, 'A review on membrane fouling control in anaerobic membrane bioreactors by adding performance enhancers', Journal of Water Process Engineering, vol. 40, pp. 101867-101867.
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Song, Y, Chetty, K, Garbe, U, Wei, J, Bu, H, O'moore, L, Li, X, Yuan, Z, McCarthy, T & Jiang, G 2021, 'A novel granular sludge-based and highly corrosion-resistant bio-concrete in sewers', Science of The Total Environment, vol. 791, pp. 148270-148270.
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Bio-concrete is known for its self-healing capacity although the corrosion resistance was not investigated previously. This study presents an innovative bio-concrete by mixing anaerobic granular sludge into concrete to mitigate sewer corrosion. The control concrete and bio-concrete (with granular sludge at 1% and 2% of the cement weight) were partially submerged in a corrosion chamber for 6 months, simulating the tidal-region corrosion in sewers. The corrosion rates of 1% and 2% bio-concrete were about 17.2% and 42.8% less than that of the control concrete, together with 14.6% and 35.0% less sulfide uptake rates, 15.3% and 55.6% less sulfate concentrations, and higher surface pH (up to 1.8 units). Gypsum and ettringite were major corrosion products but in smaller sizes on bio-concrete than that of control concrete. The total relative abundance of corrosion-causing microorganisms, i.e. sulfide-oxidizing bacteria, was significantly reduced on bio-concrete, while more sulfate-reducing bacteria (SRB) was detected. The corrosion-resistance of bio-concrete was mainly attributed to activities of SRB derived from the granular sludge, which supported the sulfur cycle between the aerobic and anaerobic corrosion sub-layers. This significantly reduced the net production of biogenic sulfuric acid and thus corrosion. The results suggested that the novel granular sludge-based bio-concrete provides a highly potential solution to reduce sewer corrosion.
Soo, A, Ali, SM & Shon, HK 2021, '3D printing for membrane desalination: Challenges and future prospects', Desalination, vol. 520, pp. 115366-115366.
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Recent years have shown a growing interest in the field of 3D printing for applications in the area of water treatment and desalination. The applications for 3D printing are applicable on numerous levels from membranes, spacers, modules, and entire plants; thanks to the high level of customisation, improving resolutions, low-cost to prototype and test designs, sustainability benefits, and reduced time and costs to fabricate new components for desalination. Previous review papers have discussed 3D printing for membrane desalination with a focus on membrane components and additive fabrication methods. This paper addresses the current limitations faced by 3D printing for water desalination and finally provides future perspectives that could address these barriers. The primary goal for this work is to compare and review the current limitations faced by 3D printing technologies in membrane desalination and provide future perspectives in order to improve its adoptability in the industry. The identified barriers include: insufficient resolutions; build volume scale; production rates; appropriate materials; costs; mechanical strength; thermal, mechanical, and chemical stability, which are factors that impede the successful application of 3D printing in membrane water treatment and desalination. Meanwhile, future directions are proposed based on the current trends in membrane research and 3D printing technologies available.
Su, G, Ong, HC, Ibrahim, S, Fattah, IMR, Mofijur, M & Chong, CT 2021, 'Valorisation of medical waste through pyrolysis for a cleaner environment: Progress and challenges', Environmental Pollution, vol. 279, pp. 116934-116934.
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The COVID-19 pandemic has exerted great shocks and challenges to the environment, society and economy. Simultaneously, an intractable issue appeared: a considerable number of hazardous medical wastes have been generated from the hospitals, clinics, and other health care facilities, constituting a serious threat to public health and environmental sustainability without proper management. Traditional disposal methods like incineration, landfill and autoclaving are unable to reduce environmental burden due to the issues such as toxic gas release, large land occupation, and unsustainability. While the application of clean and safe pyrolysis technology on the medical wastes treatment to produce high-grade bioproducts has the potential to alleviate the situation. Besides, medical wastes are excellent and ideal raw materials, which possess high hydrogen, carbon content and heating value. Consequently, pyrolysis of medical wastes can deal with wastes and generate valuable products like bio-oil and biochar. Consequently, this paper presents a critical and comprehensive review of the pyrolysis of medical wastes. It demonstrates the feasibility of pyrolysis, which mainly includes pyrolysis characteristics, product properties, related problems, the prospects and future challenges of pyrolysis of medical wastes.
Su, H, Zhang, D, Antwi, P, Xiao, L, Deng, X, Liu, Z, Long, B, Shi, M, Manefield, MJ & Ngo, HH 2021, 'Exploring potential impact(s) of cerium in mining wastewater on the performance of partial-nitrification process and nitrogen conversion microflora', Ecotoxicology and Environmental Safety, vol. 209, pp. 111796-111796.
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Sukarno, R, Putra, N, Hakim, II, Rachman, FF & Indra Mahlia, TM 2021, 'Utilizing heat pipe heat exchanger to reduce the energy consumption of airborne infection isolation hospital room HVAC system', Journal of Building Engineering, vol. 35, pp. 102116-102116.
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© 2020 Elsevier Ltd The COVID-19 pandemic in early 2020 became a global issue and received substantial attention worldwide. In a hospital, airborne infection isolation (AII) room is significant to prevent the spread of the virus to patients and medical personnel. This research aims to improve the design of the HVAC system of AII room used for removing contaminated air by making physical changes through the addition of heat pipe heat exchanger (HPHE). Experiments were conducted with varying fresh air inlet temperature between 30 and 45 °C and velocity between 1.5 and 2.5 m/s with three configurations of HPHE to investigate the performance of the HVAC system in the AII room. To ensure the HVAC system with HPHE meets the AII room requirements, this study carried out a smoke test as well as pressure and hourly air volume measurement tests between the exhaust and supply air sides. The results showed that the design of ventilation coupled with HPHE could meet the standards for the AII room. The HPHE succeeded in reducing energy consumption through pre-cooling of fresh air before entering the cooling coil device, with the highest temperature difference of 9.4 °C. The highest energy recovery was 767 W at 0.080 m3/s air volume, which can handle 46% of the total HVAC system load at operating conditions and enhance the combined efficiency of the HVAC system. Based on the results, it can be concluded that the HPHE can be coupled in the HVAC system of the hospital AII room that is safe from cross-contamination which significantly reduces the energy consumption.
Sukarno, R, Putra, N, Hakim, II, Rachman, FF & Mahlia, TMI 2021, 'Multi-stage heat-pipe heat exchanger for improving energy efficiency of the HVAC system in a hospital operating room1', International Journal of Low-Carbon Technologies, vol. 16, no. 2, pp. 259-267.
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Abstract The demands of specific requirements related to thermal comforts, such as temperature, relative humidity, inside air exchange and other factors required in a hospital operating rooms, have necessitated the development of energy-efficient heating, ventilation and air conditioning (HVAC) systems and efficient heat-recovery system using a heat-pipe heat exchanger (HPHE). The experiment was conducted by using HPHEs having three, six and nine rows, with four heat pipes in each row, arranged in a staggered configuration with a variation of fresh-air inlet temperature and velocity. The theoretical analysis was conducted using the ε-NTU method for predicting the effectiveness, outlet temperature of the evaporator side and energy recovery of the HPHE. The experimental results indicated that increasing the air-inlet temperature in the evaporator section and the number of rows increased the HPHE effectiveness but increasing the air-inlet velocity reduced the effectiveness. The highest effectiveness of 62.6% was obtained at an air-inlet temperature of 45°C with an air-inlet velocity of 2 m/s and a 9-row HPHE. The energy recovery of the HPHE increased with the number of rows, air-inlet temperature and air velocity in the evaporator section. The ε-NTU method can be used as a comparison method in the analysis of heat-recovery systems that apply HPHE air conditioning systems. Heat pipes that utilize cold-air exhaust from a room in an HVAC system can enhance efficiency and reduce emissions.
Sun, H, Zou, Y, Kaw, HY, Wang, L, Wang, G, Zhou, JL, Meng, L-Y & Li, D 2021, 'Carbon Nanofibers-Based Nanoconfined Liquid Phase Filtration for the Rapid Removal of Chlorinated Pesticides from Ginseng Extracts', Journal of Agricultural and Food Chemistry, vol. 69, no. 32, pp. 9434-9442.
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A rapid nanoconfined liquid phase filtration system (NLPF) based on solvent-confined carbon nanofibers/carbon fiber materials (CNFs/CFs) was proposed to effectively remove chlorinated pesticides from ginsenosides-containing ginseng extracts. A series of major parameters that may affect the separation performance of the CNFs-NLPF method were extensively investigated, including the water solubility of nanoconfined solvents, filtration rate, ethanol content of the ginseng extracts, and reusability of the material for repeated adsorption. The developed method showed a high removal efficiency of pesticides (85.5-97.5%), high retainment rate of ginsenosides (95.4-98.9%), and consistent reproducibility (RSD < 11.8%). Furthermore, the feasibility of the CNFs-NLPF technique to be scaled-up for industrial application was systematically explored by analyzing large-volume ginseng extract (1 L), which also verified its excellent modifiable characteristic. This filtration method exhibits promising potential as a practical tool for removing pesticide residues and other organic pollutants in food samples to assure food quality and safeguard human health.
Sun, J, Zhu, Z-R, Li, W-H, Yan, X, Wang, L-K, Zhang, L, Jin, J, Dai, X & Ni, B-J 2021, 'Revisiting Microplastics in Landfill Leachate: Unnoticed Tiny Microplastics and Their Fate in Treatment Works', Water Research, vol. 190, pp. 116784-116784.
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Due to the environmental risks caused by microplastics, understanding the sources and characteristics of microplastics and cutting off their routes into the environment are crucial. However, so far, studies on microplastics in the landfill leachate system (a major pathway of microplastics into the environment) are still limited, especially for tiny particles <50 µm that might have higher risks to the environment. This study investigated the microplastics in landfill leachate and in leachate treatment works, with a size detection limit down to 10 µm. The results showed that the microplastics particle and mass concentrations in the untreated leachate were 235.4 ± 17.1 item/L and 11.4 ± 0.8 µg/L, respectively, with tiny particles (<50 µm) accounting for over 50%. Overall, 27 polymeric materials were detected in leachate samples, with polyethylene and polypropylene being the most abundant in the untreated leachate. The neutral buoyancy of microplastics (average density: 0.94 g/cm3), together with irregular shapes, suggested they may be difficult to be removed by sedimentation. Further exploring the fate of microplastics in leachate treatment works showed that the membrane treatment effectively reduced microplastics loading to 0.14% for particle and 0.01% for mass, but the average particle density rose. The differences in polymeric materials distribution at different sampling locations and the presence of membrane-related polymer in membrane treatment effluent suggested tiny microplastics could be generated and released from membrane systems. Moreover, this study discovered that the sludge dewatering liquor could contain a high amount of microplastics, and the estimated particle loading was about 3.6 times higher than that in dewatered sludge. This suggested a new approach to microplastics mitigation through separating microplastics from the sludge dewatering liquor before its recirculation.
Sun, L, Ma, B, Pei, L, Zhang, X & Zhou, JL 2021, 'The relationship of human activities and rainfall-induced landslide and debris flow hazards in Central China', Natural Hazards, vol. 107, no. 1, pp. 147-169.
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Human activities have been recognized as one of the significant influencing factors on natural hazard, yet studies of quantitative relationship between human activities and natural hazard have been limited. The relations of human activities and hazards (landslide and debris flow) induced by heavy rainfall are quantitatively analyzed in this study and suggestions are provided for the integrated hazard mitigation management in the study area of Central China. The results show that human activities index (HAI) is an effective indicator to characterize spatiotemporal changes of human activities. The relations of rainfall-induced landslide, debris flow hazards and human activities are significant as shown in spatial distribution. The probability of rainfall-induced landslide, debris flow hazards is highly correlated with the intensity of human activities and the changes of HAI. However, in terms of temporal relations, human activities have more direct impact on rainfall-induced landslide hazard than on rainfall-induced debris flow hazard, as the frequency of landslide hazard shows a 2-year delay with HAI changing, in general, according to the cross-wavelet transform analysis. In comparison, no significant correlating period is shown between the changing human activities and the frequency of rainfall-induced debris flow hazard. Specifically, there are three types of time relationship between the changing human activities and rainfall-induced landslide, debris flow hazards in the affected counties: (1) concurrent changing, accounting for 30% of landslide and 18% of debris flow; (2) lagging relationship, accounting for 54% of landslide and 30% of debris flow; (3) no direct relationship, accounting for 16% of landslide and 52% of debris flow. The results in this study suggest that HAI is a simple and effective index for the local governments to manage human impacts on rainfall-induced landslide and debris flow hazards, and integrated prevention measures are sugg...
Sun, L, Zhou, JL, Cai, Q, Liu, S & Xiao, J 2021, 'Comparing surface erosion processes in four soils from the Loess Plateau under extreme rainfall events', International Soil and Water Conservation Research, vol. 9, no. 4, pp. 520-531.
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This research aims to improve erosion control practice in the Loess Plateau, by studying the surface erosion processes, including splash, sheet/interrill and rill erosion in four contrasting soils under high rainfall intensity (120 mm h−1) with three-scale indoor artificial experiments. Four contrasting soils as sandy loam, sandy clay loam, clay loam and loamy clay were collected from different parts of the Loess Plateau. The results showed that sediment load was significantly impacted by soil properties in all three sub-processes. Splash rate (4.0–21.6 g m−2∙min−1) was highest in sandy loam from the north part of the Loess Plateau and showed a negative power relation with the mean weight diameter of aggregates after 20 min of rainfall duration. The average sediment load by sheet/interrill erosion (6.94–42.86 g m−2∙min−1) was highest in clay loam from middle part of the Loess Plateau, and the stable sediment load after 20 min showed a positive power relation with the silt content in soil. The average sediment load increased dramatically by rill and interrill erosion (21.03–432.16 g m−2∙min−1), which was highest in loamy clay from south part of the Loess Plateau. The average sediment load after the occurrence of rill showed a positive power relation with clay content and a negative power relation with soil organic matter content. The impacts of slope gradient on the runoff rate and sediment load also changed with soil properties. The critical factors varied for different processes, which were the aggregate size for splash erosion, the content of silt particles and slope gradient for sheet/interrill erosion, and the content of clay particles, soil organic matter and slope gradient for rill erosion. Based on the results of the experiments, specific erosion control practices were proposed by targeting certain erosion processes in areas with different soil texture and different distribution of slope gradient. The findings from this study should support the i...
Sundararaman, S, Halat, DM, Choo, Y, Snyder, RL, Abel, BA, Coates, GW, Reimer, JA, Balsara, NP & Prendergast, D 2021, 'Exploring the Ion Solvation Environments in Solid-State Polymer Electrolytes through Free-Energy Sampling', Macromolecules, vol. 54, no. 18, pp. 8590-8600.
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Supasri, K, Kumar, M, Mathew, M, Signal, B, Padula, M, Suggett, D & Ralph, P 2021, 'Evaluation of Filter, Paramagnetic, and STAGETips Aided Workflows for Proteome Profiling of Symbiodiniaceae Dinoflagellate', Processes, vol. 9, no. 6, pp. 983-983.
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The integrity of coral reef ecosystems worldwide rests on a fine-tuned symbiotic interaction between an invertebrate and a dinoflagellate microalga from the family Symbiodiniaceae. Recent advances in bottom-up shotgun proteomic approaches and the availability of vast amounts of genetic information about Symbiodiniaceae have provided a unique opportunity to better understand the molecular mechanisms underpinning the interactions of coral-Symbiodiniaceae. However, the resilience of this dinoflagellate cell wall, as well as the presence of polyanionic and phenolics cell wall components, requires the optimization of sample preparation techniques for successful implementation of bottom-up proteomics. Therefore, in this study we compare three different workflows—filter-aided sample preparation (FASP), single-pot solid-phase-enhanced sample preparation (SP3), and stop-and-go-extraction tips (STAGETips, ST)—to develop a high-throughput proteotyping protocol for Symbiodiniaceae algal research. We used the model isolate Symbiodinium tridacnidorum. We show that SP3 outperformed ST and FASP with regard to robustness, digestion efficiency, and contaminant removal, which led to the highest number of total (3799) and unique proteins detected from 23,593 peptides. Most of these proteins were detected with ≥2 unique peptides (73%), zero missed tryptic peptide cleavages (91%), and hydrophilic peptides (>70%). To demonstrate the functionality of this optimized SP3 sample preparation workflow, we examined the proteome of S. tridacnidorum to better understand the molecular mechanism of peridinin-chlorophyll-protein complex (PCP, light harvesting protein) accumulation under low light (LL, 30 μmol photon m−2 s−1). Cells exposed to LL for 7 days upregulated various light harvesting complex (LHCs) proteins through the mevalonate-independent pathway; proteins of this pathway were at 2- to 6-fold higher levels than the control of 120 μmol photon m−2 s−1. Potentially, L...
Supasri, KM, Kumar, M, Segečová, A, McCauley, JI, Herdean, A, Padula, MP, O’Meara, T & Ralph, PJ 2021, 'Characterisation and Bioactivity Analysis of Peridinin-Chlorophyll a-Protein (PCP) Isolated from Symbiodinium tridacnidorum CS-73', Journal of Marine Science and Engineering, vol. 9, no. 12, pp. 1387-1387.
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Peridinin-Chlorophyll a-Proteins (PCP) are the major light harvesting proteins in photosynthetic dinoflagellates. PCP shows great variation in protein length, pigment ratio, sequence, and spectroscopic properties. PCP conjugates (PerCP) are widely used as fluorescent probes for cellular and tissue analysis in the biomedical field. PCP consists of a peridinin carotenoid; thereby, it can potentially be used as a bioactive compound in pharmaceutical applications. However, the biological activities of PCP are yet to be explored. In this study, we extracted, purified, and partially characterised the PCP from Symbiodinium tridacnidorum (CS-73) and explored its antioxidant, anti-cancer and anti-inflammation bioactivities. The PCP was purified using an ÄKTA™ PURE system and predicted to be of 17.3 kDa molecular weight (confirmed as a single band on SDS-PAGE) with an isoelectric point (pI) 5.6. LC-MS/MS and bioinformatic analysis of purified PCP digested with trypsin indicated it was 164 amino acids long with >90% sequence similarity to PCP of SymA3.s6014_g3 (belonging to clade A of Symbiodinium sp.) confirmed with 59 peptide combinations matched across its protein sequence. The spectroscopic properties of purified PCP showed a slight shift in absorption and emission spectra to previously documented analysis in Symbiodinium species possibly due to variation in amino acid sequences that interact with chl a and peridinin. Purified PCP consisted of a 19-amino-acid-long signal peptide at its N terminal and nine helixes in its secondary structure, with several protein binding sites and no DNA/RNA binding site. Furthermore, purified PCP exhibited antioxidant and in vitro anti-inflammation bioactivities, and anti-cancer activities against human metastatic breast adenocarcinoma (MDA-MB-231) and human colorectal (HTC-15) cancer cell lines. Together, all these findings present PCP as a promising candidate for continued investigations for pharmaceutical applicat...
Sutherland, DL & Ralph, PJ 2021, 'Differing growth responses in four related microalgal genera grown under autotrophic, mixotrophic and heterotrophic conditions', Journal of Applied Phycology, vol. 33, no. 6, pp. 3539-3553.
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Sutherland, DL & Ralph, PJ 2021, 'Productivity and community response along an ammonia gradient in cultured wild marine microalgae, using wastewater-derived nutrients for cost-effective feedstock production', Journal of Applied Phycology, vol. 33, no. 5, pp. 2933-2945.
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Sutherland, DL & Ralph, PJ 2021, 'Shortening hydraulic retention time through effluent recycling: impacts on wastewater treatment and biomass production in microalgal treatment systems', Journal of Applied Phycology, vol. 33, no. 6, pp. 3873-3884.
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Sutherland, DL, Burke, J & Ralph, PJ 2021, 'High-throughput screening for heterotrophic growth in microalgae using the Biolog Plate assay', New Biotechnology, vol. 65, pp. 61-68.
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Sutherland, DL, Burke, J & Ralph, PJ 2021, 'Trade-offs between effluent quality and ammonia volatilisation with CO2 augmented microalgal treatment of anaerobically digested food-waste centrate', Journal of Environmental Management, vol. 277, pp. 111398-111398.
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Diversion of food waste from landfill disposal to waste-to-energy facilities has become both an environmentally and economically viable option to support the circular bioeconomy. However, the liquid centrate produced during anaerobic digestion is high in total ammonia, with concentrations ~2000 g m-3, and can release gaseous emissions, including ammonia, methane, CO2 and nitrous oxide, to the atmosphere. Further treatment is required before discharge to sewer, or to the environment. Microalgal wastewater treatment systems augmented with CO2 offer a promising and cost-effective treatment solution for reducing both total ammonia concentrations and ammonia volatilisation. In this study, we investigate the effects of augmenting CO2 on nutrient removal and specifically nitrogen losses, as well as biomass productivity under two difference hydraulic retention times (HRT). Both CO2 addition and HRT affect nitrogen losses, with the percentage removal of total ammonia significantly lower (p < 0.01) when CO2 was added to the treatments, while increased HRT significantly increased (p < 0.05) total ammonia percentage removal. Total nitrogen budgets showed significantly lower (p < 0.01) abiotic nitrogen losses from the system when CO2 was added to the culture but at the expense of effluent quality. Both total suspended solids and volatile suspended solids significantly increased (p < 0.01) under longer HRT (8 days), with CO2 addition, while chlorophyll-a biomass significantly increased (p < 0.01) on longer HRT, regardless of CO2 addition. These results demonstrate that, while CO2 augmentation helped to mitigate ammonia losses to atmosphere, the trade-off was poorer effluent quality. Coupling CO2 augmentation with longer HRT increased biomass production and nutrient removal efficiency. This study provides an insight into how simple operational changes can alleviate some of the trade-offs between atmospheric losses and effluent quality. However, in order to manage the trade-off ...
Sutherland, DL, McCauley, J, Labeeuw, L, Ray, P, Kuzhiumparambil, U, Hall, C, Doblin, M, Nguyen, LN & Ralph, PJ 2021, 'How microalgal biotechnology can assist with the UN Sustainable Development Goals for natural resource management', Current Research in Environmental Sustainability, vol. 3, pp. 100050-100050.
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Sutherland, DL, Park, J, Ralph, PJ & Craggs, R 2021, 'Ammonia, pH and dissolved inorganic carbon supply drive whole pond metabolism in full-scale wastewater high rate algal ponds', Algal Research, vol. 58, pp. 102405-102405.
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Swain, S, Maithry Shenoy, B, Bhol, P, Yadav, S, Ranjan Jena, S, Hegde, G, Altaee, A, Saxena, M & Samal, AK 2021, 'Facet dependent catalytic activity of Pd nanocrystals for the remedy of organic Pollutant: A mechanistic study', Applied Surface Science, vol. 570, pp. 150775-150775.
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The facet effect and underlying molecular mechanisms of noble metal-based nanocrystals have shown promise as a potential candidate for various applications including catalysis and soil-water remediation. Facet-dependent catalytic activities of Palladium (Pd) nanocrystals have great significance in the field of catalysis. In this report, the well-known seed-mediated synthesis method has been used to synthesize three different Pd nanostructures of cuboctahedral (Coh), octahedral (Oh), and nanocubes (NCs). By changing the time and temperature, the growth of nanocrystals was directed along different low index planes such as {100} for NCs, {111} for Oh, and mixed planes of {100} and {111} for Coh structures. Shape-controlled Pd nanocrystals with distinctly varied surface facets were used to conduct a mechanistic study for the remediation of organic dyes. To understand the facets dependent catalysis, nanocrystals were employed for the reduction of organic pollutant 4-Nitroaniline (4-NA) to 4-Phenylenediamine (4-PDA), and the substituent effect of nitro (–NO2) groups were studied. By keeping the total surface area of particles unchanged, different volumes of nanocrystals were taken into account to carry out an accurate facet-dependent analysis. Further to extend the catalytic activity study, degradation of cationic dye, Rhodamine B (Rh B), and anionic dye, Methyl Orange (MO) were performed. The reduction and degradation processes were monitored through UV-Visible absorption spectroscopy. It was confirmed from the absorption spectra that the efficiency of Pd NCs was higher than Oh and Coh nanocrystals, which established the depiction of the best role of {100} plane out of the other two planes exposed on the surface. The catalytic trends for the asymmetric growth of planes follows the order of NCs {100}> Oh {111}> Coh {100} {111}. The specific reactivity performance of the nanocrystals was confirmed using an analytical model.
Tang, L, Liu, X, Yang, G, Xia, J, Zhang, N, Wang, D, Deng, H, Mao, M, Li, X & Ni, B-J 2021, 'Spatial distribution, sources and risk assessment of perfluoroalkyl substances in surface soils of a representative densely urbanized and industrialized city of China', CATENA, vol. 198, pp. 105059-105059.
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As a representative densely urbanized and industrialized city of China, Ningbo has experienced extremely rapid development, with a wide variety of chemical, electronic, pharmaceutical, and paper manufacturing industries. However, limited data and researches are available regarding the levels and profiles of perfluoroalkyl substances (PFASs) in surface soils of Ningbo. The present study was launched to address the knowledge gap through analyzing 27 sites in five functional regions for 9 PFASs types. Results showed that concentrations of the total PFASs (∑PFASs) ranged from 0.63 to 25.6 ng·g−1, with an average of 10.1 ng·g−1. The concentrations of ∑PFASs in different functional regions were in the order of landfill sites > industrial areas > farmlands > residential communities > animal farms. Correlation analyses between soil physicochemical properties and PFASs content revealed that concentrations of ∑PFASs were negatively correlated with soil pH but positively correlated with soil organic matter. Principal component analysis indicated that fluorochemical industrial discharge, daily life discharge, atmospheric precipitation, and electrochemical fluorination process dominated factor loadings. In addition, the ecological risk assessment based on the risk quotient demonstrated that although the risk of PFOA contamination in landfill sites was highest, there are no risk of PFOA and PFOS contamination in the surface soil environment, but needs more supervision for the neighborhood of landfill sites to avoid additional risk. This work provides new data on the different PFAS profiles in soils impacted by different contamination sources within a densely urbanized and industrialized area, and the results obtained should be useful for delineating priority sites for remediation and restauration of polluted soils.
Tijing, L, Dizon, JR & Cruz Jr., G 2021, '3D-Printed Absorbers for Solar-Driven Interfacial Water Evaporation: A Mini-Review', Advance Sustainable Science, Engineering and Technology, vol. 3, no. 1, pp. 0210103-0210103.
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Solar-driven interfacial water evaporation (SWE) is considered as a promising sustainable solution for clean water production especially for remote and off-grid communities. Various approaches have been developed in the last decade to improve the evaporation and thermal efficiency of the system, and to make it more robust for long-term operation. In recent years, 3D printing has emerged as an attractive method to fabricate simple and complex absorber geometries for SWE. In this mini-review, we present the new developments of 3D-printed solar absorbers including the various designs, fabrication strategies, challenges and opportunities. This study hopes to provide more insights into the use of additive manufacturing for improving the absorber design and performance of SWE.
Tran, CV, La, DD, Thi Hoai, PN, Ninh, HD, Thi Hong, PN, Vu, THT, Nadda, AK, Nguyen, XC, Nguyen, DD & Ngo, HH 2021, 'New TiO2-doped Cu–Mg spinel-ferrite-based photocatalyst for degrading highly toxic rhodamine B dye in wastewater', Journal of Hazardous Materials, vol. 420, pp. 126636-126636.
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The quest for finding an effective photocatalyst for environmental remediation and treatment strategies is attracting considerable attentions from scientists. In this study, a new hybrid material, Cu0.5Mg0.5Fe2O4-TiO2, was designed and fabricated using coprecipitation and sol-gel approaches for degrading organic dyes in wastewater. The prepared hybrid materials were fully characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results revealed that the Cu0.5Mg0.5Fe2O4-TiO2 hybrid material was successfully synthesized with average particle sizes of 40.09 nm for TiO2 and 27.9 nm for Cu0.5Mg0.5Fe2O4. As the calculated bandgap energy of the hybrid material was approximately 2.86 eV, it could harvest photon energy in the visible region. Results indicate that the Cu0.5Mg0.5Fe2O4-TiO2 also had reasonable magnetic properties with a saturation magnetization value of 11.2 emu/g, which is a level of making easy separation from the solution by an external magnet. The resultant Cu0.5Mg0.5Fe2O4-TiO2 hybrid material revealed better photocatalytic performance for rhodamine B dye (consistent removal rate in the 13.96 × 10-3 min-1) compared with free-standing Cu0.5Mg0.5Fe2O4 and TiO2 materials. The recyclability and photocatalytic mechanism of Cu0.5Mg0.5Fe2O4-TiO2 are also well discussed.
Tran, H-T, Lin, C, Bui, X-T, Ngo, H-H, Cheruiyot, NK, Hoang, H-G & Vu, C-T 2021, 'Aerobic composting remediation of petroleum hydrocarbon-contaminated soil. Current and future perspectives', Science of The Total Environment, vol. 753, pp. 142250-142250.
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This article provides a comprehensive review on aerobic composting remediation of soil contaminated with total petroleum hydrocarbons (TPHs). The studies reviewed have demonstrated that composting technology can be applied to treat TPH contamination (as high as 380,000 mg kg-1) in clay, silt, and sandy soils successfully. Most of these studies reported more than 70% removal efficiency, with a maximum of 99%. During the composting process, the bacteria use TPHs as carbon and energy sources, whereas the fungi produce enzymes that can catalyze oxidation reactions of TPHs. The mutualistic and competitive interactions between the bacteria and fungi are believed to sustain a robust biodegradation system. The highest biodegradation rate is observed during the thermophilic phase. However, the presence of a diverse and dynamic microbial community ensures that TPH degradation occurs in the entire composting process. Initial concentration, soil type, soil/compost ratio, aeration rate, moisture content, C/N ratio, pH, and temperature affect the composting process and should be monitored and controlled to ensure successful degradation. Nevertheless, there is insufficient research on optimizing these operational parameters, especially for large-scale composting. Also, toxic and odorous gas emissions during degradation of TPHs, usually unaddressed, can be potential air pollution sources and need further insightful characterization and mitigation/control research.
Tran, TTV, Vo, DN, Nguyen, ST, Luu, SDN, Mofijur, M & Vu, CM 2021, 'In situ sintered silver decorated 3D structure of cellulose scaffold for highly thermoconductive electromagnetic interference shielding epoxy nanocomposites', Journal of Applied Polymer Science, vol. 138, no. 40, pp. 51193-51193.
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AbstractThis study presents a 3‐dimensional (3D) network structure of cellulose scaffold (CS), which was in situ decorated with silver nanoparticles (AgNPs). The scaffold was then infiltrated with epoxy matrix and cured at elevated temperature to sinter the AgNPs; finally, highly thermoconductive epoxy composites (Ag@CS/epoxy) was obtained. The resultant Ag@CS20/epoxy composite reached a thermal conductivity of 2.52 W·m−1·K−1 at 2.2 vol% of filler loading, which shows an enhancement of over 11‐folds in the thermal conductivity compared to the neat epoxy. The superb electrical conductivity value of over 53,691 S·m−1 of the Ag@CS20/epoxy was achieved, which led to exceptional EMI SE values of 69.1 dB. Furthermore, surface temperatures during heating and cooling were also investigated to demonstrate the superior heat dissipating capacity of the Ag@CS/epoxy composite, which can be potentially put an application as thermal dissipating material in the next generation of electronics.
Tran, VH, Lim, S, Choi, PJ, An, AK, Han, DS, Phuntsho, S & Shon, H 2021, 'Submerged versus side-stream osmotic membrane bioreactors using an outer-selective hollow fiber osmotic membrane for desalination', Desalination, vol. 515, pp. 115196-115196.
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This study investigated the comparative performances, fouling mitigation efficiencies, and operational costs of side-stream and submerged osmotic membrane bioreactors (OMBR) systems using an outer-selective hollow fiber thin-film composite forward osmosis (OSHF TFC FO) membrane. Generally, the submerged OMBR system exhibited the higher fouling mitigation efficiency and a much slower flux decline rate when compared with that of the side-stream system. The side-stream OMBR system demonstrated an initial water flux of 15.8 LMH using 35 g/L NaCl as the draw solution, which was 2-fold higher than that of the submerged system when at its optimal performance. However, salinity accumulation in the reactor of the side-stream system was at a higher rate than for the submerged OMBR system. Both OMBR systems showed comparably high pollutant removal efficiencies over the experimental period. Annual operating costs for the side-stream OMBR system has been estimated to be 38% higher (OPEX) than for the submerged system. Membrane replacement cost accounted for the majority of the OPEX, over 89%, while the energy consumption and cleaning costs only accounted for relatively small portions. Therefore, reducing the membrane replacement cost is critical to realizing the commercial viability of the submerged OMBR system.
Trisnadewi, T, Kusrini, E, Nurjaya, DM, Putra, N & Mahlia, TMI 2021, 'Experimental analysis of natural wax as phase change material by thermal cycling test using thermoelectric system', Journal of Energy Storage, vol. 40, pp. 102703-102703.
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Uddin, MN, Siddiki, SYA, Mofijur, M, Djavanroodi, F, Hazrat, MA, Show, PL, Ahmed, SF & Chu, Y-M 2021, 'Prospects of Bioenergy Production From Organic Waste Using Anaerobic Digestion Technology: A Mini Review', Frontiers in Energy Research, vol. 9, pp. 1-8.
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Anaerobic digestion (AD) from organic waste has gained worldwide attention because it offers significant environmental and economic benefits. It can reduce the local waste through recycling which will conserve resources, reduce greenhouse gas emissions, and build economic resilience in the face of an uncertain future for energy production and waste disposal. The productive use of local waste through recycling conserves resources by reducing landfill space, the whole of life impacts of landfilling, and post-closure maintenance of landfills. Turning waste into a renewable energy source will assist the decarbonisation of the economy by reducing harmful emissions and pollutants. Therefore, this mini-review aims to summarise key factors and present valuable evidence for an efficient AD process. It also presents the pros and cons of different AD process to convert organic waste along with the reactor technologies. Besides, this paper highlights the challenges and the future perspective of the AD process. However, it is highlighted that for an effective and efficient AD process, appropriate temperature, pH, a strong inoculum to substrate ratio, good mixing and small particle sizes are important factors. The selection of suitable AD process and reactor is important because not all types of processes and reactors are not effective for processing organic waste. This study is of great importance for ongoing work on renewable energy generation from waste and provides important knowledge of innovative waste processing. Finally, it is recommended that the government should increase their support towards the AD technology and consider the unutilized significant potential of gaseous biofuel production.
van Ngoc, P, Turner, B, Huang, J & Kelly, R 2021, 'The durability of soil-cement columns in high sulphate environments', Geotechnical Engineering, vol. 51, no. 4, pp. 139-145.
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Soil-cement column is a geotechnical solution used for ground improvement in coastal areas. However, after long periods of exposure, the strength of these columns may decrease to below their designed safe bearing capacity, ultimately resulting in failure. In this paper, the effects of high sulphate concentrations (100%, 200%, 500% and 1000% that of seawater) on the durability of soil-cement samples were examined. In addition, the simple simulation model was applied to predict the deterioration depth and long-term strength of the soil-cement columns. The results show that the deterioration is more pronounced and occurs deeper in the presence of high sulphate concentrations. For instance, the strength of a 0.5 m diameter column exposed to 200% seawater will fall below the minimum design strength after 75 years. For higher sulphate environments (5 to 10 times that of normal seawater) the same column would never reach the minimum design strength requirement. Consequently, this has significant implications on soil-cement column when used to stabilise soils in high sulphate environments.
Varjani, S, Rakholiya, P, Shindhal, T, Shah, AV & Ngo, HH 2021, 'Trends in dye industry effluent treatment and recovery of value added products', Journal of Water Process Engineering, vol. 39, pp. 101734-101734.
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© 2020 Elsevier Ltd Increased population and industrialization generate a large number of organic pollutants that create problems on the planet earth. The level of freshwater is reducing which has pushed the society to reuse/recycle wastewater. Eco-friendly and economically sound treatment of industrial wastewater has attracted global attention and hence is a thrust area of research. Organic compounds rich wastewater can be used to generate bioenergy and value-added products from the resource recovery point of view. Wastewater treatment(s) can be used to trap energy from industrial effluents in form of biofuel, bioenergy and biogas. Recovered products can be used in various ways such as recovered nutrients for (bio)fertilizer production and algal biomass for bioplastic production. Microbial electrochemical technology is a promising approach for resource recovery. This review article aims to present and discuss trends and scientific developments about recovery of value-added products from dye industry effluent. It also provides state-of-art technical information about technologies for remediation of pollutants from dye industry effluent with emphasis on nanotechnological approaches and microbial electrochemical technologies (METs). It narrates literature on classification and properties of dyes, effects of dye pollutants on environment and human health and factors affecting degradation of dyes. Generation of bioenergy and recovery of valuables from dye industrial wastewater along with challenges and perspectives of this research area have been covered.
Varjani, S, Rakholiya, P, Yong Ng, H, Taherzadeh, MJ, Hao Ngo, H, Chang, J-S, Wong, JWC, You, S, Teixeira, JA & Bui, X-T 2021, 'Bio-based rhamnolipids production and recovery from waste streams: Status and perspectives', Bioresource Technology, vol. 319, pp. 124213-124213.
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Vo, HNP, Ngo, HH, Guo, W, Nguyen, KH, Chang, SW, Nguyen, DD, Cheng, D, Bui, XT, Liu, Y & Zhang, X 2021, 'Effect of calcium peroxide pretreatment on the remediation of sulfonamide antibiotics (SMs) by Chlorella sp.', Science of The Total Environment, vol. 793, pp. 148598-148598.
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This study investigated the effect of CaO2 pretreatment on sulfonamide antibiotics (SMs) remediation by Chlorella sp. Results showed that a CaO2 dose ranging from 0.05 to 0.1 g/g biomass was the best and led to higher SMs removal efficacy 5-10% higher than the control. The contributions made by cometabolism and CaO2 in SMs remediation were very similar. Bioassimilation could remove 24% of sulfadiazine (SDZ) and sulfamethazine (SMZ), and accounted for 38% of sulfamethoxazole (SMX) remediation. Pretreatment by CaO2 wielded a positive effect on microalgae. The extracellular polymeric substances (EPS) level of the CaO2 pretreatment microalgae was three times higher when subjected to non-pretreatment. For the long-term, pretreatment microalgae removed SMs 10-20% more than the non-pretreatment microalgae. Protein fractions of EPS in continuous operation produced up to 90 mg/L for cometabolism. For bioassimilation, SMX intensity of the pretreatment samples was 160-fold less than the non-treatment one. It indicated the CaO2 pretreatment has enhanced the biochemical function of the intracellular environment of microalgae. Peroxidase enzyme involved positively in the cometabolism and degradation of SMs to several metabolites including ring cleavage, hydroxylation and pterin-related conjugation.
Vo, T-K-Q, Dang, B-T, Ngo, HH, Nguyen, T-T, Nguyen, V-T, Vo, T-D-H, Ngo, T-T-M, Nguyen, T-B, Lin, C, Lin, K-YA & Bui, X-T 2021, 'Low flux sponge membrane bioreactor treating tannery wastewater', Environmental Technology & Innovation, vol. 24, pp. 101989-101989.
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Vu, HP, Nguyen, LN, Emmerton, B, Wang, Q, Ralph, PJ & Nghiem, LD 2021, 'Factors governing microalgae harvesting efficiency by flocculation using cationic polymers', Bioresource Technology, vol. 340, pp. 125669-125669.
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This study aims to elucidate the mechanisms governing the harvesting efficiency of Chlorella vulgaris by flocculation using a cationic polymer. Flocculation efficiency increased as microalgae culture matured (i.e. 35-45, 75, and > 97% efficiency at early, late exponential, and stationary phase, respectively. Unlike the negative impact of phosphate on flocculation in traditional wastewater treatment; here, phosphorous residue did not influence the flocculation efficiency of C. vulgaris. The observed dependency of flocculation efficiency on growth phase was driven by changes in microalgal cell properties. Microalgal extracellular polymeric substances (EPS) in both bound and free forms at stationary phase were two and three times higher than those at late and early exponential phase, respectively. Microalgae cells also became more negatively charged as they matured. Negatively charged and high EPS content together with the addition of high molecular weight and positively charged polymer could facilitate effective flocculation via charge neutralisation and bridging.
Vu, HP, Nguyen, LN, Vu, MT, Labeeuw, L, Emmerton, B, Commault, AS, Ralph, PJ, Mahlia, TMI & Nghiem, LD 2021, 'Harvesting Porphyridium purpureum using polyacrylamide polymers and alkaline bases and their impact on biomass quality', Science of The Total Environment, vol. 755, no. Pt 1, pp. 142412-142412.
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This study aims to examine the flocculation efficiency of Porphyridium purpureum (i.e. a red marine microalga with high content of pigments and fatty acids) grown in seawater medium using polyacrylamide polymers and alkaline flocculation. Polymers Flopam™ and FO3801 achieved the highest flocculation efficiency of over 99% at the optimal dose of 21 mg per g of dry biomass through charge neutralisation and bridging mechanism. The addition of sodium hydroxide, potassium hydroxide, and sodium carbonate also achieved flocculation efficiency of 98 and 91%, respectively, but high doses were required (i.e. > 500 mg per g of dry biomass). Calcium hydroxide was not as effective and could only achieve 75% flocculation efficiency. Precipitation of magnesium hydroxide was identified as the major cause of hydroxide-induced flocculation. On the other hand, sodium carbonate addition induced flocculation via both magnesium and calcium carbonate co-precipitation. The large mass of precipitates caused a sweeping effect and enmeshed the microalgal cells to trigger sedimentation. Cell membrane integrity analysis of flocculated P. purpureum indicated that polyacrylamide polymers led to significant compromised cells (i.e. 96%), compared to the alkaline bases (70-96% compromised cells). These results appear to be the first to demonstrate the high efficiency of polyacrylamide polymer and alkaline flocculation of P. purpureum but at the expense of the biomass quality.
Vu, MT, Nguyen, LN, Hasan Johir, MA, Ngo, HH, Skidmore, C, Fontana, A, Galway, B, Bustamante, H & Nghiem, LD 2021, 'Phosphorus removal from aqueous solution by steel making slag – Mechanisms and performance optimisation', Journal of Cleaner Production, vol. 284, pp. 124753-124753.
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© 2020 This study aims to evaluate a passive inexpensive process to remove the residual phosphorus (P) from wastewater treatment effluents prior to discharge to the environment. This work also differentiates between surface adsorption and chemical precipitation in the bulk solution as key P removal mechanisms by steel-making slag. Experimental results show that P removal efficiency is governed by steel-making slag particle size, initial P content and ratio of steel-making slag mass to aqueous solution volume. The results demonstrate the potential of steel-making slag for removing dissolved phosphate from wastewater especially as a polishing step. Even at an elevated concentration of P of 5 mg/L, 90% P removal was achieved using 5 kg steel-making slag with particle size of 0.15–0.6 mm for each m3 aqueous solution. Higher removal efficiency was also achievable through process optimisation. In particular, P removal by steel-making slag can be significantly enhanced, and nearly complete removal (>99%) can be achievable by buffering the aqueous solution at pH of 5.6. This study also established the isotherms and kinetics of the adsorption of P to steel-making slag to identify key removal mechanisms. Experimental data systematically indicate that P removal by steel-making slag is governed by both adsorption and chemical precipitation. At the early stage of the removal process, adsorption is the dominating removal mechanism, while the P removal via chemical precipitation can occur once the release of Ca2+ calcium into the aqueous phase is sufficient to form calcium phosphate precipitates. Overall, P removal by chemical precipitation depends on both pH and Ca2+ concentration in aqueous solution.
Vu, MT, Nguyen, LN, Hasan Johir, MA, Zhang, X, Nghiem, LD & Elimelech, M 2021, 'Biogas sparging to control fouling and enhance resource recovery from anaerobically digested sludge centrate by forward osmosis', Journal of Membrane Science, vol. 625, pp. 119176-119176.
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This study demonstrates the proof-of-concept of biogas sparging to control membrane fouling during sludge centrate pre-concentration by forward osmosis (FO). Sludge centrate sparging by biogas reduced membrane fouling (measured by water flux decline) and filtration time by two and eight times, respectively, compared to FO operation without biogas sparging at the same water recovery of 60%. In addition, the water flux was almost fully recovered by physical flushing when biogas sparging was applied. Biogas sparging also resulted in a significant improvement in the enrichment of organic, ammonia, and phosphate to close to the theoretical value based on mass balance calculation. In other words, organic matter and nutrients were retained in the bulk solution for subsequent recovery. Fouling mitigation and nutrient enrichment improvement by biogas sparging could be attributed to carbonate buffering to maintain a near neutral pH for preventing calcium phosphate precipitation on the membrane surface and ammonia volatilisation.
Walworth, NG, Hinners, J, Argyle, PA, Leles, SG, Doblin, MA, Collins, S & Levine, NM 2021, 'The evolution of trait correlations constrains phenotypic adaptation to high CO2in a eukaryotic alga', Proceedings of the Royal Society B: Biological Sciences, vol. 288, no. 1953, pp. 1-9.
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Microbes form the base of food webs and drive biogeochemical cycling. Predicting the effects of microbial evolution on global elemental cycles remains a significant challenge due to the sheer number of interacting environmental and trait combinations. Here, we present an approach for integrating multivariate trait data into a predictive model of trait evolution. We investigated the outcome of thousands of possible adaptive walks parameterized using empirical evolution data from the algaChlamydomonasexposed to high CO2. We found that the direction of historical bias (existing trait correlations) influenced both the rate of adaptation and the evolved phenotypes (trait combinations). Critically, we use fitness landscapes derived directly from empirical trait values to capture known evolutionary phenomena. This work demonstrates that ecological models need to represent both changes in traits and changes in the correlation between traits in order to accurately capture phytoplankton evolution and predict future shifts in elemental cycling.
Wang, C, Park, MJ, Seo, DH & Shon, HK 2021, 'Inkjet printing of graphene oxide and dopamine on nanofiltration membranes for improved anti-fouling properties and chlorine resistance', Separation and Purification Technology, vol. 254, pp. 117604-117604.
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© 2020 Elsevier B.V. Anti-fouling properties and chlorine resistance nature are highly desirable features for membranes used in nanofiltration (NF). Conventional polymeric NF membranes often suffer from fouling issues and poor stability under chlorine based chemicals. Therefore, in this work, a thin film composite (TFC) NF membrane was modified by coating a binding agent polydopamine (PDA) and graphene oxide (GO) using a simple and scalable inkjet printing process where the GO deposition was controlled by the number of printing cycles. The NF test results revealed the PDA-GO printed NF membranes exhibited higher salt rejection while achieving slightly lower permeate flux compared to control membrane. Moreover, the PDA-GO printed membrane exhibited enhanced anti-fouling properties where only 20% of permeate flux reduction was observed while the control membrane displayed significant reduction in flux up to 48%. Furthermore, chlorine resistance of the PDA-GO printed membrane showed reduction in salt rejection was effectively suppressed compared to the control membrane for the chlorination time of 1 and 3 h. Our work demonstrates an effective strategy to mitigate fouling and chlorine stability issues in NF membranes as well as validate inkjet printing as a versatile technique for the formation of advanced nanomaterial based membranes with high controllability of membrane properties.
Wang, C, Park, MJ, Seo, DH, Drioli, E, Matsuyama, H & Shon, H 2021, 'Recent advances in nanomaterial-incorporated nanocomposite membranes for organic solvent nanofiltration', Separation and Purification Technology, vol. 268, pp. 118657-118657.
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Recently, there is an increasing interest on organic solvent nanofiltration (OSN) for the separation and recovery of organic solvents due to the high energy consumption and the high cost involved in conventional organic solvent recovery processes. Conventional organic solvent recovery processes often involve, thermal phase separation processes such as distillation and deactivation which utilizes varying boiling points of organic solvents. Owing to such issues, pressure driven, membrane-based OSN process attracted significant attention as a low energy and low-cost alternative approach for the recovery of the organic solvents which utilizes the molecular size sieving effect via varying membrane pore sizes. However, the low solvent permeate flux, low stabilities of polymeric membranes under organic solvents and controlling the membrane properties suited for separation of various organic solvents/solutes has risen as significant challenges in implementing OSN membranes/process in practical applications. To overcome such challenges, chemically stable nanomaterials have been used as an additive material in nanocomposite membrane fabrication for OSN applications. This paper comprehensively review the nanomaterial-based OSN nanocomposite membranes based on different types of nanofillers used and the different fabrication approaches. Besides, this paper also discusses the major issues involved in different nanocomposite membrane fabrication and possible solutions for the issues involved. Moreover, the challenges and future prospective are also provided to present the current research gaps and to further develop nanomaterial-based OSN membranes for practical application.
Wang, C, Wu, L, Zhang, Y-T, Wei, W & Ni, B-J 2021, 'Unravelling the impacts of perfluorooctanoic acid on anaerobic sludge digestion process', Science of The Total Environment, vol. 796, pp. 149057-149057.
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Perfluorooctanoic acid (PFOA) is a type of persistent organic pollutant that has been detected in wastewater treatment systems, subsequently entering the waste activated sludge (WAS) anaerobic digesters. Nevertheless, how PFOA affects the anaerobic digestion of WAS has never been reported till now. In this study, a series of batch digesters were set up to assess the performance of the anaerobic sludge digestion processes with exposures to different levels of PFOA. Experimental results revealed that the increased PFOA concentration (3-60 μg/g-TS) caused the 11.1-19.2% decrease in methane production than the control. Correspondingly, the relative abundances of several key microbes related to acidification (e.g., Longilinea sp.) and methanation (e.g., Methanosaeta sp.) decreased when exposed to PFOA, as demonstrated by microbial community analysis. Further investigations based on modelling and intermediate metabolites analysis confirmed the inhibition of acidification and methanation caused by PFOA, thus decreasing the methane production potential of WAS in anaerobic digestion.
Wang, D, Yi, N, Wang, Y, Yang, J, Fu, Q, Liu, X, Yang, Q, Cai, Z, Ye, J, Liu, Y, Wang, Q & Ni, B-J 2021, 'Triclosan degradation in sludge anaerobic fermentation and its impact on hydrogen production', Chemical Engineering Journal, vol. 421, pp. 129948-129948.
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Triclosan (TCS), a widely used antibacterial agent, was accumulated at significant levels in waste activated sludge (WAS). To date, however, the interaction between TCS and sludge anaerobic fermentation was rarely reported. Hence, this work aimed to deeply understanding the degradation of TCS in sludge anaerobic fermentation and its impact on hydrogen production. Experimental results showed that ~ 45% of TCS was degraded in long-term anaerobic fermentation, with 2,4-dichlorophenol as its main intermediate. Based on the information from high performance liquid chromatography–mass spectrometry analysis, three pathways i.e., dechlorination, hydroxylation, and cleavage of ether bonds, were proposed for TCS degradation. It was found that the maximum hydrogen yield decreased from 18.6 to 12.8 mL/g VSS with the increase of TCS from 12 to 487 mg/kg TSS. One possible reason for the decreased hydrogen yield was that a part of hydrogen generated might serve as electron donors for TCS dechlorination. Besides, the presence of TCS significantly suppressed acidogenesis (an important step responsible for hydrogen generation). This inhibition to acidogenesis is likely due to that the high-affinity functional groups of TCS such as hydroxyl groups could bind to the active sites of acetate kinase (AK, a key enzyme in acidogenesis), which reduced the active sites available for original fermentation substrates. Microbial analysis revealed that TCS increased the relative abundances of potential contaminant decomposers such as Guggeheimella but inhibited the populations of hydrogen producers such as Proteiniborus, which was consistent with the results obtained by chemical analyses.
Wang, H, Gao, B, Hou, L, Shon, HK, Yue, Q & Wang, Z 2021, 'Fertilizer drawn forward osmosis as an alternative to 2nd pass seawater reverse osmosis: Estimation of boron removal and energy consumption', Frontiers of Environmental Science & Engineering, vol. 15, no. 6.
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Wang, H, Gao, Y, Gao, B, Guo, K, Shon, HK, Yue, Q & Wang, Z 2021, 'Comprehensive analysis of a hybrid FO-NF-RO process for seawater desalination: With an NF-like FO membrane', Desalination, vol. 515, pp. 115203-115203.
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Process optimization is a popular strategy to improve efficiency, reduce the energy consumption and total cost of the seawater reverse osmosis (SWRO). Forward osmosis (FO) process with a nanofiltration (NF)-like membrane has emerged as a cost-effective technology for seawater desalination pretreatment, due to its high water permeability and low energy consumption compared to RO-like FO membrane. The present work comprehensively evaluated the potential of using an NF-like FO membrane for SWRO pretreatment and analyzed the feasibility of the NF-like membrane-based FO-NF-RO process for seawater desalination. The performance of the FO-NF-RO integrated process was investigated with MgSO4, Na2SO4, and Mg(CH3COO)2 as draw solute, respectively. Besides, the energy consumption and total cost of the hybrid process were also estimated on the laboratory and large scale. The NF-like membrane-based FO process could effectively remove organic molecules and divalent ions effectively. The hybrid process product water could reach the drinking water standard in China (TDS ≤ 1000 mg/L). When water recovery was 42.0%, the hybrid process could produce freshwater with specific energy consumption of 2.99 kWh/m3 and specific water cost of 0.92 $/m3, which were comparable with the conventional SWRO process. Overall, our study revealed the feasibility of the FO-NF-RO process for seawater desalination.
Wang, L-K, Chen, X, Wei, W, Xu, Q, Sun, J, Mannina, G, Song, L & Ni, B-J 2021, 'Biological Reduction of Nitric Oxide for Efficient Recovery of Nitrous Oxide as an Energy Source', Environmental Science & Technology, vol. 55, no. 3, pp. 1992-2005.
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Chemical absorption-biological reduction based on Fe(II)EDTA is a promising technology to remove nitric oxide (NO) from flue gases. However, limited effort has been made to enable direct energy recovery from NO through production of nitrous oxide (N2O) as a potential renewable energy rather than greenhouse gas. In this work, the enhanced energy recovery in the form of N2O via biological NO reduction was investigated by conducting short-term and long-term experiments at different Fe(II)EDTA-NO and organic carbon levels. The results showed both NO reductase and N2O reductase were inhibited at Fe(II)EDTA-NO concentration up to 20 mM, with the latter being inhibited more significantly, thus facilitating N2O accumulation. Furthermore, N2O accumulation was enhanced under carbon-limiting conditions because of electron competition during short-term experiments. Up to 47.5% of NO-N could be converted to gaseous N2O-N, representing efficient N2O recovery. Fe(II)EDTA-NO reduced microbial diversity and altered the community structure toward Fe(II)EDTA-NO-reducing bacteria-dominated culture during long-term experiments. The most abundant bacterial genus Pseudomonas, which was able to resist the toxicity of Fe(II)EDTA-NO, was significantly enriched, with its relative abundance increased from 1.0 to 70.3%, suggesting Pseudomonas could be the typical microbe for the energy recovery technology in NO-based denitrification.
Wang, Y, Wei, W, Dai, X & Ni, B-J 2021, 'Coconut shell ash enhances short-chain fatty acids production from anaerobic algae fermentation', Bioresource Technology, vol. 338, pp. 125494-125494.
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This study proposed a novel method to enhance short-chain fatty acids (SCFAs) production from anaerobic algae fermentation by using coconut shell ash. The maximum SCFAs production was 683.0 mg COD/g VS at the ash dosage of 1.2 g/g TS, which was about 1.4-folds that of the control, and the enhancement of acetate production was the main path for the promotion of SCFAs. Coconut shell ash increased the pH and alkalinity of digestate, thereby reducing the use of alkaline reagents and being more resistant to acidic environments. Coconut shell ash promoted the processes of solubilization, hydrolysis and acetogenesis, and enriched hydrolytic microorganisms (e.g., Candidatus Microthrix) and acidifying microorganisms with acetate as substrate (e.g., Caldilinea and Proteiniphilum). Anaerobic fermentation residue with ash containing inorganic elements has the potential to be used as fertilizer, making this waste-control-waste strategy with more economic and environmental benefits for potential practical applications.
Wang, Y, Wei, W, Huang, Q-S & Ni, B-J 2021, 'Methane production from algae in anaerobic digestion: Role of corncob ash supplementation', Journal of Cleaner Production, vol. 327, pp. 129485-129485.
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The recycling and utilization of waste has attracted increasing attention due to the requirement of sustainable development. This study proposed a novel waste reuse technology using crop incineration waste (i.e., corncob ash) as an additive to enhance the methane production from anaerobic digestion of algae. Biochemical methane production tests demonstrated that corncob ash (0.6, 0.9 and 1.2 g/g TS (Total Solids)) enhanced methane production from algae, and the maximal methane production was 75.8 ± 1.2 ml CH4/g VS (Volatile Solids) achieved at 0.6–0.9 g/g TS of corncob ash addition, representing the relative increase of 35–37% compared to that without corncob ash. By monitoring the transformation of metabolic intermediates, corncob ash was confirmed to be beneficial to the solubilization, hydrolysis and methanogenesis processes during anaerobic algae digestion. This was supported by the microbial analysis results that corncob ash enriched the related key microorganisms, e.g., Longilinea sp. and Methanosaeta sp. Moreover, mechanism studies revealed that corncob ash alleviated ammonia inhibition and improved the electron transfer efficiency for methane production, which was probably attributed to the porous structure and high redox characteristics of corncob ash. The anaerobic digestion residue with corncob ash rich in inorganic elements (e.g., potassium, calcium and magnesium) could also be used as a potential agricultural fertilizer for soil. The novel strategy proposed in this study might provide a new paradigm of an integrated waste-control by waste to bring significant economic and environmental benefits to waste disposal.
Wang, Y, Wei, W, Wu, W, Sun, J, Xu, Q, Wang, D, Song, L & Ni, B-J 2021, 'Improving Medium-Chain Fatty Acid Production from Anaerobic Fermentation of Waste Activated Sludge Using Free Ammonia', ACS ES&T Engineering, vol. 1, no. 3, pp. 478-489.
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Wang, YK, Ma, XY, Tang, L, Wang, XC, Zhang, S, Ngo, HH & Yu, M 2021, 'Capability of shallow open-water unit for emerging contaminants attenuation and ecological safety improvement in a treated effluent polishing process', Journal of Water Process Engineering, vol. 40, pp. 101788-101788.
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Nature-based solutions of polishing treated effluent are drawing increased attention because of their potential to mitigate ecological risks, and the shallow open water unit (SOWU) process is one of the most promising options. In this study, a pilot experiment was conducted to assess the efficiency of SOWU for effluent quality polishing in a municipal wastewater treatment plant targeting 33 residual emerging contaminants (ECs) that were categorized into six groups, namely pharmaceuticals, sunscreens, bactericides, pesticides, flame retardants and phenols. In the 14-day monitoring period, each of the ECs decayed following a first order reaction, and about 61 % total ECs removal was achieved, indicating the remarkable photolysis effect of the SOWU under natural conditions. The significant removal of ECs, especially the very high removals of pharmaceuticals (76 %) and sunscreens (77 %), was associated with the attenuation of both the acute luminescent bacterial toxicity and genotoxicity. From the linear relationship between the acute toxicity and chromophoric dissolved organic matter and that between genotoxicity and UV absorbance at 254 nm, it was likely that the attenuation of biotoxicities resulted from the decay of chromophoric and aromatic compounds. By analyzing several reactive species, the excellent photoreactivity of the SOWU was further identified.
Wang, Z, Gu, X, Zhang, Y, Zhang, X, Ngo, HH, Liu, Y, Jiang, W, Tan, X, Wang, X & Zhang, J 2021, 'Activated nano-Al2O3 loaded on polyurethane foam as a potential carrier for fluorine removal', Journal of Water Process Engineering, vol. 44, pp. 102444-102444.
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Wang, Z, Ma, K, Zhang, Y, Zhang, X, Ngo, HH, Meng, J & Du, L 2021, 'High internal phase emulsion hierarchical porous polymer grafting polyol compounds for boron removal', Journal of Water Process Engineering, vol. 41, pp. 102025-102025.
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Removing micro-pollutants is an important global challenge for the development of good adsorbents and environmental engineering issues. In this work, the structure of hierarchically and interconnected porous polymer has been fabricated by a high internal phase emulsion (HIPE) with water-in-oil and used for removing boron from water. This porous polymer was synthesized via monomer radical polymerization and utilized the active sites of monomer –Cl. In this way the vicinal hydroxyl group of N-Methyl-D-glucamine (NMG) was successfully introduced and grafted into HIPE by nucleophilic substitution reaction under the catalysis of triethylamine. The maximum boron uptake capacity was 2.54 mmol/g at a boron concentration of 100 mg/L, and reached adsorption equilibrium after about 2 h. Compared to traditional adsorption membrane materials, the HIPE porous polymer had better mechanical strength and able to resist acid and alkaline in the long-term. Meanwhile the regeneration efficiency of the HIPE30 %-g-PNMG porous polymer remained at 100 % after being used for 10 cycles.
Wei, W, Chen, X & Ni, B-J 2021, 'Different Pathways of Microplastics Entering the Sludge Treatment System Distinctively Affect Anaerobic Sludge Fermentation Processes', Environmental Science & Technology, vol. 55, no. 16, pp. 11274-11283.
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Microplastics in wastewater inevitably accumulate in waste activated sludge (WAS) via wastewater biological treatment, potentially affecting the subsequent sludge treatment unit. Nevertheless, all previous research studies focused on the impacts of the direct addition of one type of model microplastics on the sludge anaerobic treatment process. This approach actually cannot reflect the real situation where multiple different microplastics simultaneously get into the wastewater treatment unit prior to the sludge treatment unit. Herein, this work innovatively proposed a more realistic method to assess the real toxic influences of microplastics on anaerobic WAS fermentation for short-chain fatty acid (SCFA) production by initially adding four typical microplastics (i.e., polyethylene terephthalate, polystyrene, and polypropylene) to the biological wastewater treatment system. Results showed that four microplastics initially entering the biological wastewater treatment reactor had little influence on the subsequent anaerobic SCFA production since WAS solubilization increased but hydrolysis and acidification decreased. In contrast, when the four microplastics were directly dosed in a WAS anaerobic fermenter, although there was no effect on WAS solubilization, the bioprocess of hydrolysis-acidification was clearly suppressed, ultimately significantly (P = 1.86 × 10-7) inhibiting the maximal SCFA production from WAS by 21.5 ± 0.1% compared to the control without microplastic addition. The excessive oxidative stress and toxic leachates from these typical microplastics reduced the relative abundances of key anaerobes (e.g., Longilinea sp.) involved in the anaerobic fermentation. This work revealed that the different pathways of microplastics entering the sludge treatment system had different impacts on anaerobic sludge fermentation processes and selecting a more realistic and accurate approach was important to evaluate the true toxicity of microplastics on the s...
Wei, W, Chen, X, Liu, Y & Ni, B-J 2021, 'Aerobic sludge digestion is distinguishingly affected by the different entering pathways of zinc oxide nanoparticles', Journal of Hazardous Materials, vol. 416, pp. 125799-125799.
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Zinc oxide nanoparticles (ZnO NPs) are widespread emerging pollutants raising global concerns about their influences on biological wastewater treatment processes. However, the impacts of ZnO NPs on aerobic sludge digestion that is a major sludge treatment process remain unknown. Herein, this study comprehensively investigated the key influences of ZnO NPs on aerobic digestion of waste activated sludge (WAS) and the potential mechanisms involved. Two different entering pathways, i.e., ZnO NPs directly entered into aerobic sludge digester and ZnO NPs initially entered into wastewater bio-treatment reactor, were tested to evaluate the different impacts. Compared to the control, ZnO NPs initially entering into wastewater bioreactor inhibited WAS degradation by 18.2 ± 0.1%, whereas ZnO NPs immediately entered into digester inhibited it by 29.7 ± 0.1%. This was accompanied by a similar decrease in inorganic nitrogen production and oxygen consumption. ZnO NPs exposure in wastewater bioreactor changed WAS characteristics in favor of solubilization in aerobic digestion. Modelling analysis indicated that ZnO NPs inhibited WAS hydrolysis, especially for their direct entering into aerobic digester. Correspondingly, microbial community was shifted in the direction against aerobic digestion by the ZnO NPs. Excessive oxidative stress and Zn2+ release represented the primary toxicity factors for the inhibition.
Wei, W, Chen, X, Peng, L, Liu, Y, Bao, T & Ni, B-J 2021, 'The entering of polyethylene terephthalate microplastics into biological wastewater treatment system affects aerobic sludge digestion differently from their direct entering into sludge treatment system', Water Research, vol. 190, pp. 116731-116731.
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The entering of the widespread polyethylene terephthalate (PET) microplastics into biological wastewater treatment system results in their retention in sewage sludge, which inevitably enters the sludge treatment system. However, all previous studies regarding the impact of microplastics on sludge treatment system were conducted by directly adding microplastics to system and focusing on anaerobic sludge digestion, although PET microplastics commonly enter into the biological wastewater treatment system first before sludge being subsequently treated. The potential impact of the microplastics on waste activated sludge (WAS) aerobic digestion is also completely missing. Therefore, herein the influences of PET microplastics with different entry paths on WAS aerobic digestion as well as the key mechanisms involved was firstly explored. Experimental results demonstrated that compared to the control test, the entering of PET microplastics to biological wastewater treatment system inhibited WAS aerobic digestion by 10.9 ± 0.1% through the decreased hydrolysis, although WAS solubilization during aerobic digestion was improved due to the change of generated WAS characteristics. In contrast, when PET microplastics was directly added to the sludge aerobic digester, there was little impact on solubilization, while the hydrolysis were inhibited seriously, thereby suppressing WAS aerobic digestion more severely by 28.9 ± 0.1%. Further investigation revealed that PET microplastics reduced the populations of key bacteria (e.g., Saprospiraceae, Chitinophagaceae and Xanthomonadaceae) involved in aerobic digestion via induced oxidative stress or/and releasing toxic chemical. This study provided a more accurate approach to assessing the real situation regarding the influences of PET microplastics on aerobic sludge digestion.
Wei, W, Chen, Z, Hao, D, Liu, X & Ni, B-J 2021, 'Natural diatomite mediated continuous anaerobic sludge digestion: Performance, modelling and mechanisms', Journal of Cleaner Production, vol. 329, pp. 129750-129750.
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Anaerobic digestion is generally restricted by the low degradability of waste activated sludge (WAS) and slow hydrolysis rate. This work provided an innovative technique to promote continuous anaerobic digestion performance mediated by natural diatomite. In continuous tests over 125 days, 2 g/g-Total solids (TS) of natural diatomite addition increased daily methane production and volatile solids (VS) destruction by 23.3% and 23.5%, respectively, leading to a 5.6% decrease in digestate volume for disposal. Microbial community in the natural diatomite mediated digester changed toward a favorable direction for anaerobic sludge digestion. Process modelling indicated that the increased natural diatomite presence increased hydrolysis rate, biomethane potential and degradation extent of the rapidly biodegradable substrates in WAS, with the highest enhancement being approximately 78.9%, 44.5% and 45.0%, respectively, achieved at 2 g/g- TS diatomite. However, the slowly biodegradable substrates in WAS stayed relatively stable. The mechanism studies revealed that natural diatomite mitigated ammonia inhibition and enhanced electron transfer for WAS-to-methane conversion mediated by its strong adsorption capacity and conductivity. The versatility of the technology proposed is also verified by the diatomite mediated experiments using different natural diatomite from different sources. Compared to the most natural minerals, diatomite exhibited either a greater anaerobic digestion performance or a lower dosage, bringing strong benefits in economy, environment and technology.
Wei, W, Shi, X, Wu, L & Ni, B-J 2021, 'Insights into coconut shell incineration bottom ash mediated microbial hydrogen production from waste activated sludge', Journal of Cleaner Production, vol. 322, pp. 129157-129157.
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Previous studies reported that alkaline anaerobic fermentation was an efficient method for microbial hydrogen production from waste activated sludge (WAS) via inhibiting hydrogen-consuming microorganisms. However, the hydrogen production is still hindered by the low hydrolysis efficiency. This study proposed a new strategy to overcome this barrier by using coconut shell incineration bottom ash as mediator, which is a renewable waste and can be obtained for free from waste-to-electricity facilities. Experiment results showed that coconut shell ash (0.6, 0.9 and 1.2 g/g-Total Solids (TS)) remarkably enhanced microbial hydrogen productions from WAS in alkaline anaerobic fermentation, with the highest output being 3.2 times that without coconut shell ash mediating. Based on process modelling analysis, coconut shell ash promoted hydrogen production rate and potential of WAS by up to 7.9 and 3.0 times, and shortened the lag-phase time from 2.1 days to 0.1 day. A mechanistic study revealed that alkaline condition inhibited methonogenesis and homoacetogenesis processes for hydrogen consumption, and coconut shell ash as mediator enhanced WAS solubilization and hydrolysis that related to hydrogen generation. This was supported by microbial community analysis, which demonstrated that microbial community was changed to be favorable to hydrogen generation. This study provided an integrated waste-control paradigm by waste with more renewable energy production, achieving double benefits in sustainability and economy.
Wei, W, Wu, L, Shi, X & Ni, B-J 2021, 'Mechanisms of CuO Nanoparticles at an Environmentally Relevant Level Enhancing Production of Hydrogen from Anaerobic Fermentation of Waste-Activated Sludge', ACS ES&T Water, vol. 1, no. 6, pp. 1495-1502.
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Wei, Y, Ye, Y, Ji, M, Peng, S, Qin, F, Guo, W & Ngo, HH 2021, 'Microbial analysis for the ammonium removal from landfill leachate in an aerobic granular sludge sequencing batch reactor', Bioresource Technology, vol. 324, pp. 124639-124639.
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Wen, H, Wang, J, Ngo, HH, Zhang, H, Bai, R, Jia, H & Zhang, X 2021, 'Numerical and experimental investigation on the forward osmosis (FO) process for the operational conditions and spacer configuration optimization in microalgae dewatering', Journal of Water Process Engineering, vol. 40, pp. 101922-101922.
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Microalgae (Scenedesmus obliquus) dewatering using forward osmosis membrane has received considerable attention for its possible application in biofuel generation. To investigate the filtration performance by analyzing permeate water flux, five different velocities (0.23 m/s, 0.31 m/s, 0.40 m/s, 0.55 m/s, 0.66 m/s) were selected in a bench-scale experiments. The results showed that the optimal flux was with 0.55 m/s velocity. Moreover, the same velocities (0.23 m/s, 0.31 m/s, 0.40 m/s, 0.55 m/s, 0.66 m/s) and three various spacer positions (0.3 mm, 1 mm and 2 mm away from the membrane) were simulated employing the computational fluid dynamics (CFD) approach. The results showed that the pressure and velocity distribution were affected by the velocities at the module inlet and the spacer configuration. And the 0.55 m/s velocity was confirmed, while the CFD revealed that the velocity distribution was relatively uniform and exerted a higher pressure on the membrane, and 0.55 m/s velocity agreed with the experiment in optimal operation. As for the spacer configurations, they were evenly distributed in the channel and the optimum structures occurred when the spacers were 1 mm away from the membrane. The spacer is beneficial for alleviating external concentration polarization (ECP) during osmosis process.
Windhagauer, M, Abbriano, RM, Ashworth, J, Barolo, L, Jaramillo-Madrid, AC, Pernice, M & Doblin, MA 2021, 'Characterisation of novel regulatory sequences compatible with modular assembly in the diatom Phaeodactylum tricornutum', Algal Research, vol. 53, pp. 102159-102159.
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Woo, YC, Yao, M, Shim, W-G, Kim, Y, Tijing, LD, Jung, B, Kim, S-H & Shon, HK 2021, 'Co-axially electrospun superhydrophobic nanofiber membranes with 3D-hierarchically structured surface for desalination by long-term membrane distillation', Journal of Membrane Science, vol. 623, pp. 119028-119028.
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© 2021 Elsevier B.V. Electrospun nanofiber membranes (ENMs) have gained increasing interest in membrane distillation (MD) applications due to their high surface area, high hydrophobicity and porosity, and controllable pore size and membrane thickness. However, despite these advantages, ENMs still suffer from wetting issues in MD. Co-axial electrospinning is an attractive strategy for the one-step fabrication of non-woven membranes with core-sheath structures and improved wetting resistance for MD application. In the present study, we investigated poly (vinylidene fluoride-co-hexafluoropropylene) (PH) as the core and PH/silica aerogel (SiA) as the sheath to obtain superhydrophobic co-axial composite ENMs. The surface characterization results indicated that the active layer (i.e., PH) of the co-axial ENMs was rough, highly porous (>80%), and superhydrophobic (contact angle >160°). Further, the co-axial ENMs possessed small pore sizes (<0.39 μm) and a suitable liquid entry pressure (>1.72 bar). Upon the application in long-term (one month) direct contact MD testing using a 3.5 wt% NaCl solution as the feed, high water vapor flux and salt rejection of 14.5 L/m2h and 99.99% were achieved, respectively, when applying the optimal 4 wt% SiA solution loading at the sheath. The ENMs fabricated using the versatile co-axial electrospinning showed great potential for long-term applications in direct contact MD desalination.
Wu, L, Wei, W & Ni, B-J 2021, 'Response to Comment on “A Critical Review on Nitrous Oxide Production by Ammonia-Oxidizing Archaea”', Environmental Science & Technology, vol. 55, no. 1, pp. 799-800.
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Wu, L, Wei, W, Song, L, Woźniak-Karczewska, M, Chrzanowski, Ł & Ni, B-J 2021, 'Upgrading biogas produced in anaerobic digestion: Biological removal and bioconversion of CO2 in biogas', Renewable and Sustainable Energy Reviews, vol. 150, pp. 111448-111448.
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Biogas produced in anaerobic digestion contains energetically useable methane (CH4) and unavoidable unwanted carbon dioxide (CO2). To increase the calorific value of this environmental-friendly renewable fuel recovered from wastewater, an upgrading process is necessary to reduce the high concentration of CO2 and increase the associated CH4 content. The pipe-line quality biomethane concentration can be achieved after biologically converting CO2 by either microorganisms or algae. Over the contemporary reviews published on the biogas upgrading, no paper has ever comprehensively covered the emerging biological methods for converting or reducing CO2. Thus, the biotechnologies for CO2 bioconversion such as H2-assisted chemoautotrophic reactor, gas fermentation, microbial electrochemical cells (MEC) and microalgae-based photosynthetic technique are comprehensively reviewed from the aspects of mechanisms, configurations, bottlenecks and efficiencies in this article. The strategies towards improving the performance of each technique regarding CO2 conversion are systematically analysed. The feasibility of each method from economic and environmental perspectives is also outlined. The outlook for biotechnologies with larger scalability and better economic or technical feasibility are then put forward to facilitate their applications for more efficient biogas upgrading.
Wu, L, Wei, W, Wang, D & Ni, B-J 2021, 'Improving nutrients removal and energy recovery from wastes using hydrochar', Science of The Total Environment, vol. 783, pp. 146980-146980.
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Hydrothermal carbonization (HTC) is an eco-friendly, flexible and efficient way to valorise wet solid wastes, producing a carbon-rich material named as hydrochar. Considerable efforts have been devoted to studying the feasibility of using hydrochar in waste management to achieve the goal of circular economy. However, a comprehensive evaluation of the impacts of hydrochar on energy recovery from anaerobic digestion (AD), nutrient reclamation, and wastewater treatment is currently lacking. To understand the influence of hydrochar type on its application, this review will firstly introduce the mechanisms and biomass treatment for hydrochar preparation. Most recent studies regarding the improvement of methane (CH4) and volatile fatty acids (VFAs) production after dosing hydrochar in anaerobic digesters are quantitatively summarized and deeply discussed. The potential of using various hydrochar as slow-fertilizer to support the growth of plants are analysed by providing quantitative data. The usage of hydrochar in remediating pollutants from wastewater as effective adsorbent is also evaluated. Based on the review, we also address the challenges and demonstrate the opportunities for the future application of hydrochar in waste management. Conclusively, this review will not only provide a systematic understanding of the up-to-date developments of improving the nutrients removal and energy recovery from wastes by using hydrochar but also several new directions for the application of hydrochar in the future.
Wu, L, Wei, W, Xu, J, Chen, X, Liu, Y, Peng, L, Wang, D & Ni, B-J 2021, 'Denitrifying biofilm processes for wastewater treatment: developments and perspectives', Environmental Science: Water Research & Technology, vol. 7, no. 1, pp. 40-67.
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Biofilms can retain microorganisms with very different growth kinetics and different electron acceptor preferences, due to their natural redox zonation.
Wu, M, Fu, Q, Huang, J, Xu, Q, Wang, D, Liu, X, Yang, J, Wu, Y, He, D, Ni, B-J & Wang, Q 2021, 'Effect of sodium dodecylbenzene sulfonate on hydrogen production from dark fermentation of waste activated sludge', Science of The Total Environment, vol. 799, pp. 149383-149383.
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Sodium dodecylbenzene sulfonate (SDBS), a typical surfactant being widely used in various applications, was highly accumulated in waste activated sludge. To date, however, its effect on hydrogen production from dark fermentation of sludge has not been documented. The work therefore aimed to explore whether and how SDBS affects hydrogen production. Experimental results showed that with an increase of SDBS from 0 to 30 mg/g TSS, the maximal hydrogen yield increased from 2.47 to 10.73 mL/g VSS (without any treatment) and from 13.05 to 23.51 mL/g VSS (under free ammonia pretreatment). Mechanism exploration showed that SDBS lowered surface tension, facilitated organics transfer from solid to liquid. SDBS also destroyed hydrogen bonding networks of protein, promoted macromolecular organics degradation. Besides, SDBS improved the electric charge in organics, then weakened the mutual repulsion, improved adsorb, interact and promoted the availability of reaction sites between anaerobes and organic substances. Enzyme activity analysis showed that SDBS not only improved the activities of enzymes related to hydrolysis and acidification processes, but also inhibited the activities of homoacetogens and methanogens. SDBS presence lowered sludge ORP and created an environment which was helpful to the growth of butyric-type bacteria, thus enhanced butyric-type fermentation, which contributed hydrogen production largely. Microbial community analysis revealed that SDBS existence affected distributions of microbial populations, and increased the abundances of hydrogen producing microorganisms (e.g., unclassified_f_Synergistaceae). PICRUSt2 analysis showed that SDBS reduced hydrogenotrophic methanogens activity for its inhibitory effect on the biotransformation of 5,10-Methenyl-THMPT to 5-methyl-THMPT.
Wu, S-L, Luo, G, Sun, J, Wei, W, Song, L & Ni, B-J 2021, 'Medium chain fatty acids production from anaerobic fermentation of waste activated sludge', Journal of Cleaner Production, vol. 279, pp. 123482-123482.
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© 2020 Elsevier Ltd The utilization of waste activated sludge (WAS) to recover energy in the form of methane or short-chain fatty acids (SCFAs) is generally restricted by the low energy density of products and poor degradability of WAS. Herein, this study reported a novel alternative WAS fermentation technology to produce high-energy medium-chain fatty acids (MCFAs) from WAS in a one-stage anaerobic fermentation system using ethanol as electron donor. The MCFAs production and WAS degradation at different ethanol levels were investigated. The increased ethanol levels resulted in increasing MCFAs production (from 1875 to 6115 mg chemical oxygen demand (COD)/L) and selectivity (from 30.3 to 56.2%). The main MCFAs products were n-caproate and n-caprylate at lower level of ethanol, while n-caproate was the sole MCFA product at higher level of ethanol with longer chain alcohol (i.e., n-hexanol) produced as well. The ethanol markedly increased WAS degradation, with the greatest degradation (0.72 g COD/g volatile solids (VS)) being 1.9 times of that without ethanol (0.38 mg COD/mg VS, at 0 mmol/L), which was ascribed to the advancement of sludge solubilization, hydrolysis and acidification. Microbial community revealed that the ethanol participation induced the community shift to the favorable direction for hydrolysis-acidification and chain elongation in anaerobic WAS fermentation.
Wu, S-L, Wei, W & Ni, B-J 2021, 'Enhanced methane production from anaerobic digestion of waste activated sludge through preliminary pretreatment using calcium hypochlorite', Journal of Environmental Management, vol. 295, pp. 113346-113346.
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Methane recovery from waste activated sludge (WAS) through anaerobic digestion is generally restricted by the poor degradability of WAS. Herein, a novel sludge pretreatment technology by using the calcium hypochlorite (Ca(ClO)2) in enhancing the methane production from WAS anaerobic digestion was reported. The solubilization of WAS was significantly increased after 10-240 mg Ca(ClO)2/g VS (VS: volatile solids) pretreatment for 48 h, under which the solubilization was 1.7-3.4 folds (i.e., 0.17-0.34 mg SCOD/mg VS; SCOD: soluble chemical oxygen demand) higher than that without Ca(ClO)2 pretreatment (i.e., 0.1 mg SCOD/mg VS). Correspondingly, the methane production was increased from 250.0 ± 5.3 mL/g VS to 385.1 ± 3.3 mL/g VS with the doses of Ca(ClO)2 increasing from 10 mg/g VS to 240 mg/g VS, resulted in an increasing methane production of 3.6%-59.7% than that without Ca(ClO)2 pretreatment. The microbial community composition results exhibited that the populations of key acidogens (e.g., Longilinea sp.) and methanogens (e.g., Methanosaeta sp.) were both reduced significantly. Moreover, Ca(ClO)2 decreased the cells viability, leading to a 76.2% reduction of living cells fraction. Accordingly, it was further confirmed that high dosage of Ca(ClO)2 could inhibit three microbial-related processes relevant to methane production, i.e., acidification, hydrolysis and methanogenesis.
Wu, S-L, Wei, W, Xu, Q, Huang, X, Sun, J, Dai, X & Ni, B-J 2021, 'Revealing the Mechanism of Biochar Enhancing the Production of Medium Chain Fatty Acids from Waste Activated Sludge Alkaline Fermentation Liquor', ACS ES&T Water, vol. 1, no. 4, pp. 1014-1024.
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Wu, W, Zhu, S, Huang, X, Wei, W & Ni, B-J 2021, 'Mechanisms of persulfate activation on biochar derived from two different sludges: Dominance of their intrinsic compositions', Journal of Hazardous Materials, vol. 408, pp. 124454-124454.
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Sludge-derived biochar (SDBC) has been regarded as persulfate (PS) activator during the remediation of organic contamination. However, the complexity of sludge composition makes it difficult to predict the activity of SDBC and the efficacy of PS. To improve the understanding of how the composition of sludge regulated activity of its parent SDBC towards PS activation, we used two SDBCs derived from different sludges with significantly different organic compositions and metals. Results indicated the higher content of organic and nitrogen content in sludge led to higher polymerization and condensation of carbon layer and more moieties in SDBC1, whereas more Fe species (e.g. Fe-O, Fe2+ and Fe3+) formed in SDBC2. According to the results of phenol (PN) degradation in SDBC/PS, the apparent rate constants (kobs) of SDBC2-700 (0.0037 min-1) was 2 folds higher than that of SDBC1-700 (0.0016 min-1), whereas the SDBC1-500 (6.0 ×10-4 min-1) exhibited higher kobs than that of SDBC2-500 (4.9 ×10-4 min-1). The difference of PS activation by different SDBCs mainly relied on generated reactive oxygen species (ROS). The persistent free radicals (PFRs) and Fe species acted as redox sites for generated ROS, which were depended on the organic compositions and involved metals in used sludges.
Wu, W, Zhu, S, Huang, X, Wei, W, Jin, C & Ni, B-J 2021, 'Determination of Instinct Components of Biomass on the Generation of Persistent Free Radicals (PFRs) as Critical Redox Sites in Pyrogenic Chars for Persulfate Activation', Environmental Science & Technology, vol. 55, no. 11, pp. 7690-7701.
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Persulfate (PS) activation on biochar (BC) is a promising technology for degrading the aqueous organic contaminants. However, the complexity of activation mechanisms and components in biomass that used to produce BC makes it difficult to predict the performance of PS activation. In this study, we employed eight sludges as the representative biomass that contained absolutely different organic or inorganic components. Results showed that the elemental composition, surface properties, and structures of the sludge-derived BCs (SBCs) clearly depended on the inherent components in the sludges. The intensities of persistent free radicals (PFRs) in the electron paramagnetic resonance (EPR) correlated positively with N-containing content of sludges as electron shuttle, but negatively with the metal content as electron acceptor. Linking with PFRs as crucial sites of triggering a radical reaction, a poly-parameter relationship of predicting PS activation for organic degradation using the sludge components was established (kobs,PN = 0.004 × Cprotein + 0.16 × CM-0.895 -0.118). However, for the PS activation on those SBCs without PFRs, this redox process only relied on the sorption or conductivity-related characteristics, not correlating with the content of intrinsic components in biomass but with pyrolysis temperatures. This study provided insightful information of predicting the remediation efficiency of PS activation on BCs and further understanding the fate of contaminants and stoichiometric efficiency of oxidants in a field application.
Xiao, R, Ni, B-J, Liu, S & Lu, H 2021, 'Impacts of organics on the microbial ecology of wastewater anammox processes: Recent advances and meta-analysis', Water Research, vol. 191, pp. 116817-116817.
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Anaerobic ammonium oxidation (anammox) represents a promising technology for wastewater nitrogen removal. Organics management is critical to achieving efficient and stable performance of anammox or integrated processes, e.g., denitratation-anammox. The aim of this systematic review is to synthesize the state-of-the-art knowledge on the multifaceted impacts of organics on wastewater anammox community structure and function. Both exogenous and endogenous organics are discussed with respect to their effects on the biofilm/granule structure and function, as well as the interactions between anammox bacteria (AnAOB) and a broad range of coexisting functional groups. A global core community consisting of 19 taxa is identified and a co-occurrence network is constructed by meta-analysis on the 16S rDNA sequences of 149 wastewater anammox samples. Correlations between core taxa, keystone taxa, and environmental factors, including COD, nitrogen loading rate (NLR) and C/N ratio are obtained. This review provides a holistic understanding of the microbial responses to different origins and types of organics in wastewater anammox reactors, which will facilitate the design and operation of more efficient anammox-based wastewater nitrogen removal process.
Xie, S, Li, X, Pham, CU, Nguyen, HV, Song, Y, Chetty, K, Kulandaivelu, J, Wang, C, Hai, F & Jiang, G 2021, 'Co-digestion of primary sewage sludge with drinking water treatment sludge: A comprehensive evaluation of benefits', Bioresource Technology, vol. 330, pp. 124994-124994.
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Anaerobic co-digestion of primary sludge with two types of drinking water treatment sludge (DWTS), namely iron- or aluminum-rich DWTS (Fe- or Al-DWTS) were systematically evaluated by biochemical methane potential tests, kinetic modelling, downstream process parameters and microbial community analysis. Specific methane yields decreased approximately 19% to 123 mL·g-1 VS, while the hydrolysis constant kh decreased from 0.21 d-1 to 0.18 d-1 for Fe-DWTS at 10% to 40% dosages. On the contrary, specific methane yields decreased 45-55% for Al-DWTS, and kh decreased to 0.14 d-1 at 40% dosage. Significant removals (>95%) of phosphate and hydrogen sulfide were observed for Fe- and Al-DWTS additions at 40% dosage. Microbial community analysis revealed that Al-DWTS increased the abundance of most hydrogenotrophic methanogens, while Fe-DWTS increased the abundance of acetoclastic methanogens. Kinetic modelling further revealed that Fe- and Al-DWTS additions affected the hydrolysis and methanogenesis process kinetics and the methane yield differently.
Xu, B, Liu, S, Zhou, JL, Zheng, C, Weifeng, J, Chen, B, Zhang, T & Qiu, W 2021, 'PFAS and their substitutes in groundwater: Occurrence, transformation and remediation', Journal of Hazardous Materials, vol. 412, pp. 125159-125159.
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Poly- and perfluoroalkyl substances (PFAS) are increasingly investigated due to their global occurrence and potential human health risk. The ban on PFOA and PFOS has led to the use of novel substitutes such as GenX, F-53B and OBS. This paper reviews the studies on the occurrence, transformation and remediation of major PFAS i.e. PFOA, PFNA, PFBA, PFOS, PFHxS, PFBS and the three substitutes in groundwater. The data indicated that PFOA, PFBA, PFOS and PFBS were present at high concentrations up to 21,200 ng L−1 while GenX and F-53B were found up to 30,000 ng L−1 and 0.18–0.59 ng L−1, respectively. PFAS in groundwater are from direct sources e.g. surface water and soil. PFAS remediation methods based on membrane, redox, sorption, electrochemical and photocatalysis are analyzed. Overall, photocatalysis is considered to be an ideal technology with low cost and high degradation efficacy for PFAS removal. Photocatalysis could be combined with electrochemical or membrane filtration to become more advantageous. GenX, F-53B and OBS in groundwater treatment by UV/sulfite system and electrochemical oxidation proved effective. The review identified gaps such as the immobilization and recycling of materials in groundwater treatment, and recommended visible light photocatalysis for future studies.
Xu, Q, Fu, Q, Liu, X, Wang, D, Wu, Y, Li, Y, Yang, J, Yang, Q, Wang, Y, Li, H & Ni, B-J 2021, 'Mechanisms of potassium permanganate pretreatment improving anaerobic fermentation performance of waste activated sludge', Chemical Engineering Journal, vol. 406, pp. 126797-126797.
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Potassium permanganate (KMnO4), one typical strong oxidant, is used extensively in various applications. However, its impact on anaerobic fermentation of waste activated sludge is unknown. This paper therefore aims to investigate its effect on generation of short-chain fatty acids (SCFAs) and qualities of fermentation liquor and fermented solid sludge. Experimental results showed that when KMnO4 increased from 0 to 0.1 g/TSS, the highest SCFAs production enhanced from 33.9 to 251.8 mg COD/g VSS. The mechanism analysis revealed that KMnO4 addition increased the disintegration of sludge cells and the degradation of substantial recalcitrant organics in sludge such as humus and lignocellulose, thereby provided more substances for SCFAs generation. Ultraviolet absorption spectroscopy analysis showed that KMnO4 addition destroyed unsaturated conjugated bonds and decreased organics aromaticity, thereby promoting humus and lignocellulose degradation. GC/MS analyses showed that several micro-molecular substances (e.g., acid-like, alkane-like, and alcohol-like organics) were generated from KMnO4 pretreated humus and lignocellulose, and some of them were demonstrated to serve as substrates to produce SCFAs. The enzyme activity and model-based analyses showed that although KMnO4 restrained all the microorganisms to some extends, the activities of SCFAs generators were much higher than those of SCFAs consumers. In addition, the sludge mixture was separated into liquid and solid fraction after anaerobic fermentation, and the components in fermentation liquid and solid sludge were tested. It was found that the addition of KMnO4 effectively reduced the categories and total detected frequency of refractory organic pollutants in fermentation liquid, which improved the quality of the produced SCFAs. KMnO4 addition also increased the inactivation of fecal coliforms and degradation of emerging contaminants in fermented sludge, which were helpful to its final disposal.
Xu, Q, Huang, Q-S, Luo, T-Y, Wu, R-L, Wei, W & Ni, B-J 2021, 'Coagulation removal and photocatalytic degradation of microplastics in urban waters', Chemical Engineering Journal, vol. 416, pp. 129123-129123.
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The global concerns to the environmental pollution and health risks by microplastics (MPs) urgently require action to develop effective and sustainable processes to deal with this problem. Coagulation removal and photocatalytic degradation, considered as cost- and energy-effective techniques, have attracted growing attention to remove MPs from urban waters. However, its removal behavior and degradation mechanism have not been systematically summarized. Therefore, the recent progress on coagulation and photocatalysis for MPs removal was comprehensively reviewed in this study. Particularly, the effects of parameters (e.g., type and dosage of coagulant, environmental conditions, characteristics of MPs and catalyst type, etc) and removal mechanisms were commendably discussed. Moreover, the challenges of current techniques application process and the potential coping strategies were also put forward. This review will not only help to deeply understand the detailed processes and mechanisms for removing MPs by coagulation and photocatalysis but also provide constructive information and useful data for future researches relevant to the enhanced removal of MPs from urban waters.
Xu, Z, Qi, C, Zhang, L, Ma, Y, Li, G, Nghiem, LD & Luo, W 2021, 'Regulating bacterial dynamics by lime addition to enhance kitchen waste composting', Bioresource Technology, vol. 341, pp. 125749-125749.
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This study examined bacterial dynamics in response to lime addition to enhance kitchen waste composting using modular network analysis. Bacterial communities could be separated into three meta-modules corresponding to the mesophilic, thermophilic, and mature stage of composting. Lime addition at 1% (wet weight) suppressed acidogens and denitrifiers (e.g. Lactobacillus and Acinetobacter) at the mesophilic stage to reduce greenhouse gas emissions. The matrix pH and temperature were also increased by lime addition via hydrogen reaction to favor bacterial growth and activity. Thus, thermophilic bacteria (e.g. Thermoactinomycetaceae and Planifilum) were enriched with lime addition to facilitate lignocellulose biodegradation for humus formation at the thermophilic stage. Further lime addition to 1.5% reduced ammonia emission at the thermophilic stage via chemical fixation. Moreover, lime inhibited denitrifiers but proliferated nitrifiers at the mature stage to decrease nitrous oxide emission and enhance nitrate content, respectively. As such, lime addition improved both biotic and abiotic composting performance.
Xu, Z, Xu, W, Zhang, L, Ma, Y, Li, Y, Li, G, Nghiem, LD & Luo, W 2021, 'Bacterial dynamics and functions driven by bulking agents to mitigate gaseous emissions in kitchen waste composting', Bioresource Technology, vol. 332, pp. 125028-125028.
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This study investigated the impacts of different bulking agents (i.e. garden waste, cornstalks, and spent mushroom substrates) on bacterial structure and functions for gaseous emissions during kitchen waste composting. High-throughput sequencing was integrated with functional Annotation of Prokaryotic Taxa (FAPROTAX) to decipher the bacterial structure and functions. Results show that adding cornstalks constructed a more complex and mutualistic bacterial network to enhance organic biodegradation. This scenario, however, aggravated the emission of ammonia and hydrogen sulphide with the enrichment of the genus Bacillus and Desulfitibacter at the thermophilic stage of composting to facilitate ammonification and sulphur-related respiration, respectively. By contrast, spent mushroom substrates facilitated the proliferation of the genus Pseudomonas to promote nitrate reduction at the cooling stage, leading to considerable emission of nitrous oxide. Compared to these two agents, garden waste contained less easily biodegradable substances to limit bacterial mutualism, thereby reducing gaseous emissions in composting.
Yadav, S, Jena, SR, M.B., B, Altaee, A, Saxena, M & Samal, AK 2021, 'Heterostructures of 2D materials-quantum dots (QDs) for optoelectronic devices: challenges and opportunities', Emergent Materials, vol. 4, no. 4, pp. 901-922.
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Despite the fact that organic semiconductors have promising properties such as ease of fabrication and low cost, further improvements in the properties and performances of both materials and devices remain necessary. The unique characteristics of two-dimensional (2D) materials including carbon-based nanomaterials, black phosphorus, transition-metal carbides, nitrides, and carbonitrides are the most promising nanomaterials for optoelectronic devices due to their atomic thickness and excellent optical properties. These 2D-layered materials can be combined to form a monolayer (lateral 2D heterostructure) or a multilayer stack (vertical 2D heterostructure). Nevertheless, their light detection efficiency is limited by their low light absorption ability and the rapid recombination of photogenerated electron-hole pairs. Also, recently, it has been discovered that quantum dots (QDs) have excellent local photon capture capabilities which can enhance the overall efficiency of photodetectors in 2D materials. As a result, QDs are integrated with 2D heterostructures to improve the performance of 2D materials and overcome their limitations. Integration of QDs with 2D material enhances electronic performance. In the present review, we have discussed the important properties, synthesis, and optoelectronic applications of 2D materials. This article also provides an overview of state of the art and highlights the promising results of the research field for next-generation heterostructures of 2D materials-QDs. 2D heterostructures with QD composite materials are successfully shown for optoelectronic properties. Graphical abstract: [Figure not available: see fulltext.]
Yang, G, Sun, Y, Limin qin, Li, M, Ou, K, Fang, J & Fu, Q 2021, 'Direct-ink-writing (DIW) 3D printing functional composite materials based on supra-molecular interaction', Composites Science and Technology, vol. 215, pp. 109013-109013.
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Direct ink writing (DIW) is the most versatile AM technique in terms of materials development, it enables the creation of complex 3D shapes using any material by formulating a paste with controlled rheology. One of the main challenges of DIW is to design and formulate the viscoplastic and self-healing soft inks that easily flow under shear and quickly recover upon deposition. Researchers often look for flexible approaches that can be adapted to formulate printing inks with a wide range of materials. Here we report a supra-molecular interaction system composed of triethanolamine and ammonium oleate for application in DIW technology. Almost any materials (eg. rubber, plastic, ceramic, metal and composites) can be integrated into the ink system, and then can be 3D printing via shear-thinning DIW method. Furthermore, the solid contents of the ink system are higher than 80%, avoiding the formation of porous structure and dimensional changes after shaping. Present DIW method was used to construct sensors based on multi-material for application in real-time monitoring human health. This work may provide an new method to develop 3D printing materials for various practical applications.
Yang, Y, Hu, Y, Duan, A, Wang, XC, Hao Ngo, H & Li, Y-Y 2021, 'Characterization of preconcentrated domestic wastewater toward efficient bioenergy recovery: Applying size fractionation, chemical composition and biomethane potential assay', Bioresource Technology, vol. 319, pp. 124144-124144.
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Ye, Y, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Varjani, S, Ding, A, Bui, X-T & Nguyen, DP 2021, 'Bio-membrane based integrated systems for nitrogen recovery in wastewater treatment: Current applications and future perspectives', Chemosphere, vol. 265, pp. 129076-129076.
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Nitrogen removal is crucial in wastewater treatment process as excessive nitrogen content could result in eutrophication and degradation of aquatic ecosystems. Moreover, to satisfy the fast-growing need of fertilizers due to an increase in human population, recovering nitrogen from wastewater is of the most sustainable approach. Currently, the membrane technique integrated with biological processes namely bio-membrane based integrated system (BMIS) is a promising technology for recovering nitrogen from wastewater, including osmotic membrane bioreactors, bioelectrochemical systems and membrane photobioreactors. In this review study, the nitrogen recovery in different BMHSs, the role of operational parameters and the nitrogen recovery mechanism were discussed. Apart from this, the implementation of nitrogen recovery at pilot- and full-scale was summarized. Perspectives on the major challenges and recommendations of the BMIS for the nitrogen recovery in wastewater treatment were proposed, in which the integrated technologies and more scale-up studies regarding nitrogen recovery by the BMISs were also highlighted and recommended.
Ying, L, Sinutok, S, Pramneechote, P, Aiyarak, P, Ralph, PJ & Chotikarn, P 2021, 'Physiological Responses of Pocillopora acuta and Porites lutea Under Plastic and Fishing Net Stress', Frontiers in Marine Science, vol. 8, pp. 1-13.
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Marine debris has become a global problem affecting coral health around the globe. However, the photophysiological responses of corals to marine debris stress remain unclear. Therefore, this study firstly investigated transparent and opaque plastic bag shading and fishing nets directly contacting the coral. Photosynthetic performance, pigment content, symbiont density, and calcification rate of a branching coral Pocillopora acuta and a massive coral Porites lutea were investigated after 4 weeks of exposure to marine debris. The results show that the maximum quantum yield of PSII significantly decreased in P. lutea with all treatments, while P. acuta showed no effect on the maximum quantum yield of PSII from any treatments. Transparent plastic bag shading does not affect P. acuta, but significantly affected the maximum photochemical efficiency of P. lutea. Photoacclimation of cellular pigment content was also observed under opaque plastic bag shading for both species at week 2. Fishing nets had the strongest effect and resulted in P. acuta bleaching and P. lutea partial mortality as well as a decline in zooxanthellae density. Calcification rate of P. acuta significantly decreased with treatments using opaque plastic bag and fishing net, but for P. lutea only the treatment with fishing net gave any observable effects. This study suggests that the sensitivities of corals to marine debris differ strongly by species and morphology of the coral.
Yu, S, Peng, L, Xu, Y, Song, S, Xie, G-J, Liu, Y & Ni, B-J 2021, 'Optimizing light sources for selective growth of purple bacteria and efficient formation of value-added products', Journal of Cleaner Production, vol. 280, pp. 124493-124493.
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The slow growth and inefficient productivity of value-added products are the main obstacles to industrialization of purple non-sulfur bacteria (PNSB)-based technology for clean production from wastewater. To overcome these, a strain of PNSB was obtained through selective cultivation and purification, which was subsequently identified as Rhodobacter sphaeroides. The impacts of different light sources (i.e. halogen lamp, incandescent lamp, infrared light, and light-emitting diodes (LEDs) of white, red, blue, green and yellow) were investigated on the production of biomass, pigments and protein by Rb. sphaeroides. Results suggested that, in addition to infrared light, green and yellow LED, most light sources managed to keep the purity of Rb. sphaeroides above 96%. After 7-day cultivation, halogen lamp and infrared light yielded the highest concentrations of biomass (5.78 g SS L−1) and pigments (22.6 mg L−1), respectively. Highest protein-to-biomass ratio (82%) was observed under blue LED, while maximum protein concentration (4.43 g protein L−1) was obtained under incandescent lamp. The infrared light and incandescent lamp might account for the higher production of pigments and protein, respectively. Considering the culture screening, productivity of biomass, pigments and protein as well as energy efficiency together, incandescent lamp was the optimal light source in lab scale. It also gave rise to the highest net profit of $ 14.43 per ton of wastewater treated in a desktop extrapolation evaluating economic benefit of full-scale PNSB-based wastewater recovery process. The results jointly demonstrated that appropriate light source (i.e. incandescent lamp) would boost the microbial protein production and enhance the protein content, which is of great importance to cost control in practice.
Yuan, C, Chen, W, Yang, Z, Huang, Z & Yu, X 2021, 'The effect of various cations/anions for MgH2 hydrolysis reaction', Journal of Materials Science & Technology, vol. 73, pp. 186-192.
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MgH2 is regarded as a potential hydrolysis material for the hydrogen generation due to its high theoretical hydrogen yield, abundant source on earth and environmentally friendly hydrolysates. However, the quickly formed passive magnesium hydroxide layer on the surface of MgH2 will hinder its further hydrolysis reaction, leading to sluggish reaction kinetics and low H2 yield. In this paper, we explore the improvement of different anions and cations in solutions for the hydrolysis of MgH2. It is found that the cations in the solution promote the reaction rate of MgH2 hydrolysis through the hydrolysate-induced growth effect, among which the fastest hydrogen yield can get 1664 mL/g within a few minutes in the Fe2(SO4)3 solution. As for the anions, it enables different microstructures of the Mg(OH)2 hydrolysate which give rise to enhanced water utilization. Specially, for the mixed 0.5 M MgCl2 + 0.05 M MgSO4 solution, the water utilization rate attains the optimum value of 51.3 %, much higher than that of the single MgCl2 or MgSO4 solutions. These findings are of great significance for the application of MgH2 hydrolysis as hydrogen generation.
Yuan, D, Zhou, X, Jin, W, Han, W, Chi, H, Ding, W, Huang, Y, He, Z, Gao, S & Wang, Q 2021, 'Effects of the Combined Utilization of Ultrasonic/Hydrogen Peroxide on Excess Sludge Destruction', Water, vol. 13, no. 3, pp. 266-266.
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Excess sludge reduction has been a research hotspot for a long time. Ultrasonic treatment of excess sludge was an efficient and green pretreatment method, and also can be combined with the addition of oxidants. To improve the effect of ultrasound treatment on sludge destruction, hydrogen peroxide (H2O2) was added to examine the combined results in the current study. The effects of the ultrasound/hydrogen peroxide system on the release of sludge organic matter during the destruction process were studied. Single-factor experiments were carried out to determine the optimal operating conditions. With the initial pH of 11.0, H2O2 concentration of 0.5 mmol/L, initial sludge concentration of 17 g/L, and 15 min ultrasonic treatment, the maximum soluble chemical oxygen demand (ΔSCOD) in the sludge supernatant after destruction was achieved at 3662.78 ± 239.21 mg/L, with a disintegration degree of 28.61 ± 2.14%, sludge reduction rate of 19.47 ± 0.82%, and the change of mixture sludge concentration (ΔMLSS) of 3.31 ± 0.06 g/L. Meanwhile, the release of nitrogen and phosphorus were greatly improved. Under the optimal conditions, the release of total nitrogen (TN), ammonia nitrogen (NH3-N) and total phosphorus (TP) were 282.30 ± 24.06 mg/L, 25.68 ± 2.09 mg/L, and 105.69 ± 7.84 mg/L, respectively. The current work had provided solid evidence showing the addition of hydrogen peroxide can effectively strengthen the treatment effects of ultrasound on sludge destruction.
Yuan, Z, Yu, Y, Wei, L, Wang, C, Zhong, X, Sui, X, Yu, Z, Han, DS, Shon, H & Chen, Y 2021, 'Thermo-osmosis-Coupled Thermally Regenerative Electrochemical Cycle for Efficient Lithium Extraction', ACS Applied Materials & Interfaces, vol. 13, no. 5, pp. 6276-6285.
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Yusof, NK, Abas, PE, Mahlia, TMI & Hannan, MA 2021, 'Techno-Economic Analysis and Environmental Impact of Electric Buses', World Electric Vehicle Journal, vol. 12, no. 1, pp. 31-31.
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Electric vehicles are a leading candidate in the clean energy market. This paper aims to analyse the feasibility of the deployment of electric buses (EB) based on the existing bus routes in Brunei, by the use of life cycle cost analysis and the analysis of the parameters that influence the overall life cycle cost. The findings from the study revealed that EB are significantly more expensive than diesel buses (DB), with their acquisition and maintenance costs contributing substantially to their overall life cycle cost. In order to promote EB deployment, the government needs to look simultaneously into providing subsidies for EB and imposing taxes on DB, the provision of charging infrastructure, and ensuring maintenance capability, as well as increasing the current subsidised diesel price. It was also shown that increasing the cost of diesel to the average US diesel price of USD$3.101/L, an initial subsidy of USD$67,586 towards the purchase of EB, and a tax of USD$67,586 for the purchase of DB would allow EB to compete in the market, with the amount of tax and subsidy being gradually reducible over time, as EB and battery technology becomes more mature. From an environmental perspective, the emissions from EB come out higher than the emissions from DB. The efficiency of electric power generation needs to be enhanced, and renewable energy sources and the adoption of carbon capture technology need to be explored in order to exploit the full benefit of EB and ensure more environmentally sustainable bus operation.
Zamri, MFMA, Bahru, R, Suja', F, Shamsuddin, AH, Pramanik, SK & Fattah, IMR 2021, 'Treatment strategies for enhancing the removal of endocrine-disrupting chemicals in water and wastewater systems', Journal of Water Process Engineering, vol. 41, pp. 102017-102017.
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The emergence of endocrine-disrupting chemicals (EDC) in water and wastewater systems has high-risk implications for the environment. This manuscript discusses the treatment strategies for the removal of EDC in water and wastewater systems. The reviewed treatment outlines for EDC removal are classified into physical, biological, and chemical treatments. The application of EDC treatments is discussed based on the removal and degradation process to eliminate the EDC compounds. Interestingly, the physical treatment of membrane filtration processes has been an efficient method for EDC removal without using chemical disinfection in a treatment system. Nevertheless, like other EDC treatment methods, the membrane filtrations are not able to remove emerging contaminants completely. Thus, the overall factor of limitations and challenges in EDC treatment methods such as solubility, hydrophilicity, degradability, and polarity are discussed as to understand the applicability of the treatment techniques from the degradation pathways and the by-products produced. The integration treatment strategies through alternative approaches, such as sequential and hybrid treatments that enhanced the considerable removal of EDC are rely on the sample characteristics. Therefore, this article gathered each treatment approach's effectiveness and limitations, providing a potential outlook of EDC treatment strategies in water and wastewater treatment systems.
Zamri, MFMA, Hasmady, S, Akhiar, A, Ideris, F, Shamsuddin, AH, Mofijur, M, Fattah, IMR & Mahlia, TMI 2021, 'A comprehensive review on anaerobic digestion of organic fraction of municipal solid waste', Renewable and Sustainable Energy Reviews, vol. 137, pp. 110637-110637.
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© 2020 Elsevier Ltd This article aims to comprehensively review the anaerobic digestion (AD) process utilising the organic fraction of municipal solid waste (OFMSW) substrate. The AD of OFMSW has received considerable attention due to its significant energy and nutrient recovery as well as its greenhouse gas (GHG) mitigation potential. AD is a biological process involving treating and stabilising organic matter in the absence of oxygen accomplished by a consortium of microorganisms and occurs under hydrolysis, acidogenesis, acetogenesis, and methanogenesis phases. The hydrolysis phase is recognised as the primary rate-limiting step. Thus, exploring the ways to speed up the hydrolysis process will maximise biogas production. The key factors affecting the digestion efficiency include feedstock quality, pre-treatment process, design and selection of digestion process and process conditions including pH, temperature, carbon to nitrogen (C: N) ratio, organic loading rate and hydraulic retention time. The review reveals that solid-state anaerobic digestion (SSAD) is best suited for OFMSW due to its high solid concentration (>15%) and better process performance. The continuous digestion with thermophilic temperatures was found to be the best condition for high solid AD process. The plug flow and continuous stir tank reactors were the best performing options to control the biological conditions for the digestate post-treatment. Proper selection of the parameters for the whole process is crucial in ensuring process feasibility and economic sustainability of AD of OFMSW. The study revealed that the AD of OFMSW could play a significant role to mitigate waste and waste-related problems.
Zavafer, A, Bates, H, Labeeuw, L, Kofler, JR & Ralph, PJ 2021, 'Normalized chlorophyll fluorescence imaging: A method to determine irradiance and photosynthetically active radiation in phytoplankton cultures', Algal Research, vol. 56, pp. 102309-102309.
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Zavahir, S, Elmakki, T, Gulied, M, Ahmad, Z, Al-Sulaiti, L, Shon, HK, Chen, Y, Park, H, Batchelor, B & Han, DS 2021, 'A review on lithium recovery using electrochemical capturing systems', Desalination, vol. 500, pp. 114883-114883.
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Zdarta, A, Smułek, W, Bielan, Z, Zdarta, J, Nguyen, LN, Zgoła-Grześkowiak, A, Nghiem, LD, Jesionowski, T & Kaczorek, E 2021, 'Significance of the presence of antibiotics on the microbial consortium in wastewater – The case of nitrofurantoin and furazolidone', Bioresource Technology, vol. 339, pp. 125577-125577.
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Zdarta, J, Jankowska, K, Bachosz, K, Degórska, O, Kaźmierczak, K, Nguyen, LN, Nghiem, LD & Jesionowski, T 2021, 'Enhanced Wastewater Treatment by Immobilized Enzymes', Current Pollution Reports, vol. 7, no. 2, pp. 167-179.
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Abstract Purpose of Review In the presented review, we have summarized recent achievements on the use of immobilized oxidoreductases for biodegradation of hazardous organic pollutants including mainly dyes, pharmaceuticals, phenols, and bisphenols. In order to facilitate process optimization and achievement of high removal rates, effect of various process conditions on biodegradation has been highlighted and discussed. Recent Findings Current reports clearly show that immobilized oxidoreductases are capable of efficient conversion of organic pollutants, usually reaching over 90% of removal rate. Further, immobilized enzymes showed great recyclability potential, allowing their reuse in numerous of catalytic cycles. Summary Collected data clearly indicates immobilized oxidoreductases as an efficient biocatalytic tools for removal of hazardous phenolic compounds, making them a promising option for future water purification. Data shows, however, that both immobilization and biodegradation conditions affect conversion efficiency; therefore, process optimization is required to achieve high removal rates. Nevertheless, we have demonstrated future trends and highlighted several issues that have to be solved in the near-future research, to facilitate large-scale application of the immobilized oxidoreductases in wastewater treatment.
Zeng, S, Sun, J, Chen, Z, Xu, Q, Wei, W, Wang, D & Ni, B-J 2021, 'The impact and fate of clarithromycin in anaerobic digestion of waste activated sludge for biogas production', Environmental Research, vol. 195, pp. 110792-110792.
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Clarithromycin retained in waste activated sludge (WAS) inevitably enters the anaerobic digestion system. So far, the complex impacts and fate of clarithromycin in continuous operated WAS anaerobic digestion system are still unclear. In this study, two semi-continuous long-term reactors were set up to investigate the effect of clarithromycin on biogas production and antibiotic resistance genes (ARGs) during WAS anaerobic digestion, and a batch test was carried out to explore the potential metabolic mechanism. Experimental results showed that clarithromycin at lower concentrations (i.e., 0.1 and 1.0 mg/L) did not affect biogas production, whereas the decrease in biogas production was observed when the concentration of clarithromycin was further increased to 10 mg/L. Correspondingly, the relative abundance of functional bacteria in WAS anaerobic digestion (i.e., Anaerolineaceae and Microtrichales) was reduced with long-term clarithromycin exposure. The investigation of ARGs suggested that the effect of methylation belonging to the target site modification played a critical role for the anaerobic microorganisms in the expression of antibiotic resistance, and ermF, played dominated ARGs, presented the most remarkable proliferation. In comparison, the role of efflux pump was weakened with a significant decrease of two detected efflux genes. During WAS anaerobic digestion, clarithromycin could be partially degraded into metabolites with lower antimicrobial activity including oleandomycin and 5-O-desosaminyl-6-O-methylerythronolide and other metabolites without antimicrobial activity.
Zeweldi, HG, Bendoy, AP, Park, MJ, Shon, HK, Johnson, EM, Kim, H-S, Kim, H, Chung, W-J & Nisola, GM 2021, 'Forward osmosis with direct contact membrane distillation using tetrabutylphosphonium p-toluenesulfonate as an effective and safe thermo-recyclable osmotic agent for seawater desalination', Chemosphere, vol. 263, pp. 128070-128070.
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Zeweldi, HG, Bendoy, AP, Park, MJ, Shon, HK, Kim, H-S, Johnson, EM, Kim, H, Chung, W-J & Nisola, GM 2021, 'Supramolecular host-guest complex of methylated β-cyclodextrin with polymerized ionic liquid ([vbim]TFSI) as highly effective and energy-efficient thermo-regenerable draw solutes in forward osmosis', Chemical Engineering Journal, vol. 411, pp. 128520-128520.
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© 2021 Elsevier B.V. Supramolecular inclusion complexes with lower critical solution temperature (LCST) properties were investigated for the first time as forward osmosis (FO) draw solutes. Randomly methylated-β-cyclodextrin (Rm-β-CD) host molecules accommodate polymerized ionic liquids (([vbim]TFSI)n PILs) through their hydrophobic TFSI− anions as guests. LCST properties were tuned by varying the chain lengths of ([vbim]TFSI)n, from which, short-chain oligo([vbim]TFSI) was found most suitable. Draw solutions (DS) of Rm-β-CD/oligo([vbim]TFSI) complex have highly tunable cloud-point temperatures (Tc), fast LCST kinetics and sufficient osmotic properties for an efficient FO. Under PRO mode, 0.5 M Rm-β-CD/0.078 M oligo([vbim]TFSI) induced competitive FO water flux (Jv ~13.73 L m−2h−1) and negligible reverse solute flux (Js ~4.41 × 10−3 mol m−2h−1) against DI water feed. It successfully processed different saline feeds (0.034 M and 0.6 M NaCl) with reasonable FO performance and superior Js/JV ~0.001 mol m−2h−1, demonstrating its competence for FO desalination. When heated slightly above its Tc = 29 °C (TTP = 30 °C), thermal precipitation (TP) is ensued with the release of TFSI− anions in oligo([vbim]TFSI) from Rm-β-CD. Due to its hydrophobicity, oligo([vbim]TFSI) precipitates while entrapping the suspended Rm-β-CDs between its chains causing flocculation and sedimentation. Thus, with only +5 °C heating above FO temperature (25 °C), 95% of draw solutes are effectively recovered from the spent DS after settling. Residual (~5%) Rm-β-CD in the DS supernatant is subsequently removed via nanofiltration at 99.33% rejection, producing non-toxic water effluent based on in vitro cytotoxicity results. Energy consumption estimates reveal the feasibility of Rm-β-CD/oligo([vbim]TFSI) as it requires minimal heat energy for recovery. This study offers new insights on the potential of host-guest complexes as a new class of energy-efficient draw solutes for FO desalination technology.
Zhang, G, Morrison, D, Bao, G, Yu, H, Yoon, CW, Song, T, Lee, J, Ung, AT & Huang, Z 2021, 'An Amine–Borane System Featuring Room‐Temperature Dehydrogenation and Regeneration', Angewandte Chemie International Edition, vol. 60, no. 21, pp. 11725-11729.
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AbstractAmine–borane complexes have been extensively studied as hydrogen storage materials. Herein, we report a new amine–borane system featuring a reversible dehydrogenation and regeneration at room temperature. In addition to high purity H2, the reaction between ethylenediamine bisborane (EDAB) and ethylenediamine (ED) leads to unique boron–carbon–nitrogen 5‐membered rings in the dehydrogenation product where one boron is tricoordinated by three nitrogen atoms. Owing to the unique cyclic structure, the dehydrogenation product can be efficiently converted back to EDAB by NaBH4 and H2O at room temperature. This finding could lead to the discovery of new amine boranes with potential usage as hydrogen storage materials.
Zhang, G, Morrison, D, Bao, G, Yu, H, Yoon, CW, Song, T, Lee, J, Ung, AT & Huang, Z 2021, 'An Amine–Borane System Featuring Room‐Temperature Dehydrogenation and Regeneration', Angewandte Chemie, vol. 133, no. 21, pp. 11831-11835.
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AbstractAmine–borane complexes have been extensively studied as hydrogen storage materials. Herein, we report a new amine–borane system featuring a reversible dehydrogenation and regeneration at room temperature. In addition to high purity H2, the reaction between ethylenediamine bisborane (EDAB) and ethylenediamine (ED) leads to unique boron–carbon–nitrogen 5‐membered rings in the dehydrogenation product where one boron is tricoordinated by three nitrogen atoms. Owing to the unique cyclic structure, the dehydrogenation product can be efficiently converted back to EDAB by NaBH4 and H2O at room temperature. This finding could lead to the discovery of new amine boranes with potential usage as hydrogen storage materials.
Zhang, G, Ngo, HH, Peng, Y, Bux, F & Mannina, G 2021, 'Biological nutrients removal and recovery', Bioresource Technology, vol. 320, no. Pt B, pp. 124377-124377.
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Zhang, J, Sui, K, Wang, D, Liu, X, Li, L, Li, X, Xu, Q, Liu, Y, Wang, Q & Yang, Q 2021, 'Free ammonia pretreatment assists potassium ferrate to enhance the production of short-chain fatty acids from waste activated sludge: Performance, mechanisms and applications', Journal of Cleaner Production, vol. 328, pp. 129620-129620.
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Anaerobic fermentation of waste activated sludge (WAS) is often limited by low disintegration rates of WAS and quick consumptions of short-chain fatty acids (SCFAs) by methanogens. This work proposed a novel, efficient and harmless pretreatment approach i.e., using potassium ferrate (PF) combined with free ammonia (FA), to enhance the disintegration of WAS and the accumulation of SCFAs from WAS anaerobic fermentation. It was found in this work, the best pretreating condition of WAS is 0.10 g PF/g VSS + 180 mg FA/L, under which the SCFAs consistence reached its maximum value (342.5 mg COD/g VSS), which was respectively 7.45-fold, 3.50-fold and 2.06-fold of that from the Blank, FA and PF reactor. Further in-depth mechanism study showed that the disintegration of WAS promoted and the biodegradability of fermentation broth enhanced under the PF + FA pretreatment condition. Moreover, the populations of fecal coliforms in WAS reduced significantly when PF + FA was adopted. Considering that FA could be produced in situ during the ammoniating process, the findings in this work promoted the utilization of PF-based pretreatment method in actual operations.
Zhang, L, Gonzales, RR, Istirokhatun, T, Lin, Y, Segawa, J, Shon, HK & Matsuyama, H 2021, 'In situ engineering of an ultrathin polyamphoteric layer on polyketone-based thin film composite forward osmosis membrane for comprehensive anti-fouling performance', Separation and Purification Technology, vol. 272, pp. 118922-118922.
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Thin film composite (TFC) membranes easily suffer from fouling induced by oil and other pollutants during forward osmosis (FO) due to the relatively hydrophobic chemistry and rough structure of polyamide (PA). To achieve comprehensive anti-fouling properties, poly(2-methacryloyloxyethyl phosphorylcholine-co-2-aminoethyl methacrylate hydrochloride) (MPC-co-AEMA) was immobilized on top of a polyketone (PK)-based TFC membrane following a single-step simultaneous deposition with dopamine. The adhesive properties of polydopamine (PDA), as well as the covalent interactions between PDA and MPC-co-AEMA, ensured the firm immobilization of the MPC-co-AEMA on PA layer. As a result of the simultaneous deposition of PDA and MPC-co-AEMA, a high-performance and superhydrophilic and underwater superoleophobic TFC membrane was engineered. In addition, the outstanding water adsorption capacity of the polyamphoteric layer resulted in better protein adhesion mitigation. FO operation using various foulants also demonstrated a high fouling resistance of the PK-TFC-PDA/MPC membrane, especially during the treatment of wastewater emulsion containing high concentration of oil and bovine serum albumin (BSA). In summary, the findings in this study could provide insights into the preparation of anti-fouling membranes for wastewater purification using FO.
Zhang, W, Zhang, X, Huang, Z, Li, H-W, Gao, M, Pan, H & Liu, Y 2021, 'Recent Development of Lithium Borohydride‐Based Materials for Hydrogen Storage', Advanced Energy and Sustainability Research, vol. 2, no. 10, pp. 2100073-2100073.
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Lithium borohydride (LiBH4) has been attracting extensive attention as an exemplary high‐capacity complex hydride for solid‐state hydrogen storage applications because of its high hydrogen capacities (18.5 wt% and 121 kg H2 m−3). However, the strong and highly directional covalent and ionic bonds within LiBH4 structure induce high desorption temperatures, slow kinetics, and poor reversibility, which make large‐scale application impractical. To improve its hydrogen cycling performance, several strategies including cation/anion substitution, catalyst doping, reactive compositing, and nanoengineering, have been developed to tailor the thermodynamics and kinetics of hydrogen storage process. For example, largely reduced operation temperatures and remarkably improved hydrogen storage reversibility under moderate conditions have been achieved by the synergistic effect of nanostructuring and nanocatalysis. Herein, the state‐of‐the‐art development of LiBH4‐based hydrogen storage materials is summarized, including the basic physical and chemical properties, the principles of thermodynamic and kinetic manipulation and the strategies to improve hydrogen storage properties. The remaining challenges and the main directions of future research are also discussed.
Zhang, X & Fatahi, B 2021, 'Assessing axial load transfer mechanism of open-ended tubular piles penetrating in weak rocks using three-dimensional discrete element method', Computers and Geotechnics, vol. 137, pp. 104267-104267.
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Zhang, X, Cheng, X, Reng, J, Ma, X, Liu, Q, Yao, P, Ngo, HH & Nghiem, LD 2021, 'UV assisted backwashing for fouling control in membrane bioreactor operation', Journal of Membrane Science, vol. 639, pp. 119751-119751.
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Zhang, X, Liu, Y, Ren, Z, Zhang, X, Hu, J, Huang, Z, Lu, Y, Gao, M & Pan, H 2021, 'Realizing 6.7 wt% reversible storage of hydrogen at ambient temperature with non-confined ultrafine magnesium hydrides', Energy & Environmental Science, vol. 14, no. 4, pp. 2302-2313.
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Non-confined MgH2 nanoparticles of 4–5 nm diameter enable reversible storage of hydrogen up to 6.7 wt% at 30 °C.
Zhang, X, Nan, J, Liu, T, Xiao, Q, Liu, B, He, X, Ngo, HH & Ding, A 2021, 'Modeling and simulation of an extended ASM2d model for the treatment of wastewater under different COD: N ratio', Journal of Water Process Engineering, vol. 40, pp. 101831-101831.
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Zhang, X, Yang, Y, Ngo, HH, Guo, W, Wen, H, Wang, X, Zhang, J & Long, T 2021, 'A critical review on challenges and trend of ultrapure water production process', Science of The Total Environment, vol. 785, pp. 147254-147254.
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The recent and vigorous developments in semiconductor technology strictly request better quality and large quantity of ultrapure water (UPW) for their production. It is crucial to secure a large amount of raw water for the future development of UPW production. Using reclaimed water as alternative raw water source to produce UPW is therefore considered the feasible trend and solution for sustainable use of water resources towards a common future practice in UPW production. The challenge of using reclaimed water is due to its higher content of organic pollutants, especially small molecule organic pollutants such as urea, which are difficult to remove through traditional UPW production process. Consequently, improving the existing UPW production process to meet the water standard desired in the semiconductor industry is essential. This paper reviewed the current traditional processes for removing organic matters in UPW production, including ion-exchange (IX) adsorption, granular activated carbon (GAC) adsorption, reverse osmosis (RO) and ultraviolet (UV) irradiation. The potential problems in the actual UPW production process were identified when using reclaimed water as raw water source. A new strategy of applying the advanced oxidation process (AOPs) to UPW production as a supplementary unit to guarantee UPW quality was proposed. Its feasibility and research focus were then analyzed and discussed in obtaining a new solution for a future development of the UPW production process.
Zhang, X, Zhang, L, Zhang, W, Ren, Z, Huang, Z, Hu, J, Gao, M, Pan, H & Liu, Y 2021, 'Nano-synergy enables highly reversible storage of 9.2 wt% hydrogen at mild conditions with lithium borohydride', Nano Energy, vol. 83, pp. 105839-105839.
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In this work, we report an effective synthetic strategy to obtain LiBH4 featuring low-temperature and highly reversible hydrogen cycling. This is achieved by a unique nanocomposite structure where LiBH4 nanoparticles of 5–10 nm on graphene are decorated by Ni nanocrystals of 2–4 nm. The prepared LiBH4 nanocomposite reversibly desorbs and absorbs ~9.2 wt% hydrogen at 300 °C with a stable cyclability for up to 100 cycles, superior to all the literature results reported so far. The decisive factor affecting the hydrogen cycling is the reactivity of boron toward hydrogen. The formation of stable B12H122- cluster during hydrogen cycling has been successfully prevented. The synergetic effects of nanostructuring and nanocatalysis lead to efficient formation of BH4¯ during hydrogenation and elemental boron during dehydrogenation. This breakthrough sheds light on new strategies to explore borohydride family for practical hydrogen storage applications.
Zhang, Y-T, Wei, W & Ni, B-J 2021, 'Revealing the mechanism of zinc oxide nanoparticles facilitating hydrogen production in alkaline anaerobic fermentation of waste activated sludge', Journal of Cleaner Production, vol. 328, pp. 129580-129580.
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Zinc oxide nanoparticles (ZnO NPs) has been documented to accumulate in waste activated sludge (WAS). Nevertheless, its potential effect on hydrogen accumulation during anaerobic fermentation has never been reported. Such impact exists in anaerobic sludge treatment systems but is unrecognized before. Therefore, this work aims to explore the effect of ZnO NPs on hydrogen accumulation during WAS fermentation while avoiding hydrogen consumption by maintaining pH around 10. Deep insights into the mechanisms of the enhanced hydrogen production after dosing ZnO NPs can then be provided. The 21.1 to 74.0 mL-H2/g-VS hydrogen yields were obtained after dosing 0–150 mg/g-TS ZnO NPs into the system, which is 2.5 times higher than the control. The zinc ions released from ZnO NPs did not pose obvious cytotoxic effect on organisms based on the mechanism exploration of this study. The reactive oxygen species (ROS) induced by ZnO NPs facilitated sludge disintegration and improved the biodegradability of released organics, but restrained the bio-processes of hydrolysis and acetogenesis simultaneously. This was further verified by the microbial community analysis, as the abundance of key microbes related to hydrolysis and acetogenesis was reduced evidently in the presence of 150 mg/g-TS ZnO NPs. This study would provide a green and economic strategy for the sustainable engineering application of WAS containing ZnO NPs.
Zhang, Y-T, Wei, W, Wang, Y & Ni, B-J 2021, 'Enhancing methane production from algae anaerobic digestion using diatomite', Journal of Cleaner Production, vol. 315, pp. 128138-128138.
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Zhang, Z, Li, X, Liu, H, Gao, L & Wang, Q 2021, 'Free ammonia pretreatment enhances the removal of antibiotic resistance genes in anaerobic sludge digestion', Chemosphere, vol. 279, pp. 130910-130910.
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Sludge has been recognized as a reservoir of antibiotic resistance genes (ARGs) in the wastewater treatment plants. Our previous study has demonstrated that free ammonia (FA, i.e., NH3-N) pretreatment is an effective method for enhancing anaerobic digestion of sludge. However, the effects of FA pretreatment on the removal of ARGs in the anaerobic sludge digestion is still unknown. In this study, several ARGs representing various antibiotic classes and integrase gene (intI1) which is crucial for horizontal transfer of ARGs were chosen. This study demonstrated that combined FA pretreatment (420 mg NH3-N/L for 24 h, under which the highest anaerobic sludge biodegradability was achieved in our previous study) and anaerobic digestion could enhance the removal of aac(6')-Ib-cr, blaTEM, sul2, tetA, tetB and tetX from sludge by 17-74% compared with anaerobic digestion without FA pretreatment, resulting in a lower ARGs abundance in the anaerobically digested sludge. This is caused by the removal of tested ARGs during FA pretreatment and the reduced abundance of potential microbial hosts of ARGs due to FA pretreatment during anaerobic digestion. The removal of IntI1 was not significantly affected by FA pretreatment and intI1 did not play a large role in the fate of the tested ARGs in this study. This study indicated that FA pretreatment for anaerobic digestion could potentially reduce the spread of ARGs from the sludge to the natural environment during sludge disposal or reuse.
Zhang, Z, Liu, H, Wen, H, Gao, L, Gong, Y, Guo, W, Wang, Z, Li, X & Wang, Q 2021, 'Microplastics deteriorate the removal efficiency of antibiotic resistance genes during aerobic sludge digestion', Science of The Total Environment, vol. 798, pp. 149344-149344.
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Sludge from wastewater treatment plants (WWTPs) is considered to be reservoirs of antibiotic resistance genes (ARGs), which can be efficiently removed by sludge treatment processes, e.g., aerobic sludge digestion. However, recent studies report microplastics, which also accumulate in sludge, may serve as carriers for ARGs. In the presence of microplastics, whether ARGs can still be efficiently destroyed by aerobic sludge digestion remains to be urgently investigated. In this study, the fate of ARGs during aerobic digestion was investigated with and without the addition of three prevalent categories of (i.e., polyvinyl chloride (PVC), polyethylene (PE), and polyethylene terephthalate (PET)). Nine ARGs and class 1 integron-integrase gene (intI1) that represents the horizontal transfer potential of ARGs were tested in this study. Compared with the control, the ARGs removal efficiency decreased by 129.6%, 137.0%, and 227.6% with the presence of PVC, PE, and PET, respectively, although a negligible difference was observed with their solids reduction efficiencies. The abundance of potential bacterial hosts of ARGs and intI1 increased in the reactors with the addition of microplastics, suggesting that microplastics potentially selectively enriched bacterial hosts and promoted the horizontal transfer of ARGs during aerobic sludge digestion. These may have contributed to the deteriorated ARGs removal efficiency. This study demonstrated that microplastics in sludge would decrease the ARGs removal efficiency in aerobic digestion process, potentially leading to more ARGs entering the local environment during sludge disposal or utilization.
Zhao, E, May, E, Walker, PD & Surawski, NC 2021, 'Emissions life cycle assessment of charging infrastructures for electric buses', Sustainable Energy Technologies and Assessments, vol. 48, pp. 101605-101605.
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This paper evaluates and calculates the magnitude of greenhouse gases produced from the implementation of electric bus charging stations into existing bus depots concurrent with the transitioning of the commuter bus fleets into electrified powertrains. To achieve this, a comprehensive and in-depth emissions life cycle assessment is conducted and utilises the Australian based fleets as a case study, focusing particularly on Sydney city and Inner West regions. To define the scope and system boundary for this type of study, the authors have chosen bus routes that take into account city, suburban, and highway driving. The study conducts a life cycle assessment of electric bus charging stations that incorporates the greenhouse gas emissions produced from the production, transportation, installation, operations, and decommissioning phases. Additionally, three alternate scenarios are explored: time variance, high shares of renewables, and net-zero emissions by 2050. Results show that contributions from infrastructure development and the transition to electrified buses are substantially outweighed by operation emissions. The operations phase is heavily dependent on the electricity grid-mixes carbon intensity and contributes the most greenhouse gas emissions (98.8%), followed by production (0.69%), recycling and disposal (0.48%), installation (0.01%), and transportation (0.01%). The current Australian electricity grid-mix produces approximately 1.2 ∼ 1.4 times more greenhouse emissions than when combusting diesel fuel. Thus, net-zero emissions will not be achieved without substantial grid-mix decarbonisation. This study also finds that regional-specific parameters heavily influences the final life cycle emissions calculations. For the case-specific scenario, it is found that transitioning the existing transport bus fleet into electric powertrains has the potential to significantly reduce the impact on climate change compared to diesel buses. However, it can only...
Zhao, E, Walker, PD, Surawski, NC & Bennett, NS 2021, 'Assessing the life cycle cumulative energy demand and greenhouse gas emissions of lithium-ion batteries', Journal of Energy Storage, vol. 43, pp. 103193-103193.
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Zhao, J, Hou, T, Wang, Q, Zhang, Z, Lei, Z, Shimizu, K, Guo, W & Ngo, HH 2021, 'Application of biogas recirculation in anaerobic granular sludge system for multifunctional sewage sludge management with high efficacy energy recovery', Applied Energy, vol. 298, pp. 117212-117212.
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This study investigated the possibility of biogas recirculation-driven anaerobic granular sludge system for sewage sludge treatment, aiming to develop an energy sufficient and multifunctional anaerobic digestion (AD) system for sewage sludge with biogas upgrading, sludge stabilization and self-aggregation. Results show that biogas recirculation could enhance the CH4 production rate by 31–44% and shorten the lag-phase duration to 0.08–0.2 day with simultaneous increment of CH4 content (> 83% in this study). The reason is mainly associated with the stronger interspecies electron transfer under the biogas recirculation condition. In addition, 37–40% better dewaterability of the digested sludge was achieved, implying the occurrence of self-aggregation of microbial cells induced by biogas recirculation. Energy balance analysis reflects that this sewage sludge treatment system could enhance the net energy recovery by 78–85%. Moreover, almost no obvious influence was noticed on the seed granules’ composition and properties. These findings suggest that the biogas recirculation-driven anaerobic granular sludge system could be a promising alternative for sewage sludge treatment, which can improve biogas quality and sludge dewaterability simultaneously towards sludge self-aggregation with no addition of other chemicals.
Zhao, X, Lu, C, Yang, L, Chen, W, Xin, W, Kong, X-Y, Fu, Q, Wen, L, Qiao, G & Jiang, L 2021, 'Metal organic framework enhanced SPEEK/SPSF heterogeneous membrane for ion transport and energy conversion', Nano Energy, vol. 81, pp. 105657-105657.
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© 2020 Elsevier Ltd Bioinspired nanofluidic devices have drawn increasing global interest due to their giant applicable potential in a wide range of fields. By mimicking biological prototype, it is expected to achieve high energy conversion efficiency and tunable ion transport. However, the low osmotic conversion efficiency, weak ion transport capability and poor mechanical performance limit practical application. We designed a class of heterogeneous membrane consisting of a support layer and a thin top layer to meet fundamental requirements. To achieve higher power generation, we incorporated metal organic framework (MOF) nanosheets (dispersed phase) into polymer matrix (continuous phase) to afford a mixed matrix top layer. This unique structure addressed the geometric restriction associated with the polymeric specie due to their limited pore accessibility. As a result, the presented membranes produced high power density of ca. 7 W m−2 and a high energy conversion efficiency of ca. 40% under a salinity gradient of 50 (0.5 M|0.01 M, NaCl). This work thus offers an insight into a new methodology in the development of a novel membrane technology for highly efficient energy conversion.
Zheng, L, Li, K, Wang, Q, Naidu, G, Price, WE, Zhang, X & Nghiem, LD 2021, 'Proof of concept: Integrated membrane distillation-forward osmosis approaches water production in a low-temperature CO2 capture', Environmental Technology & Innovation, vol. 22, pp. 101508-101508.
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This study investigated the removal of CO2 from flue gas by an integrated membrane distillation-forward osmosis (MD–FO) system. Monoethanolamine (MEA) and sodium glycinate solutions were loaded with CO2 from a mixture of CO2 and N2 (1:9 in volume ratio) to simulate synthetic flue gas. CO2 desorption from the amine solution was evaluated using MD at 80 °C. Interaction between amines and the membrane polymeric matrix could alter the membrane surface hydrophobicity; however, under all experimental conditions it was still sufficiently hydrophobic for MD operation. Amine loss during MD operation for CO2 desorption was insignificant. FO was used to provide make-up water and cooling to the regenerated amine solution after CO2 desorption by MD. The results showed stable FO water flux when wastewater effluent was used as the source for make-up water. Repetitive CO2 loading and desorption experiments showed 87.0% and 88.1% CO2 re-absorption efficiency for MEA and sodium glycinate in the second cycle, respectively. Further investigation of this hybrid system is suggested to advance the CO2 desorption by MD process and water production by FO process.
Zhou, Y, Ma, Y, Qi, C, Shen, L, Fu, Q, Sun, Y & Liu, Y 2021, 'Superhydrophobic surface based on nano-engineering for enhancing the durability of anticorrosion', Surface Engineering, vol. 37, no. 3, pp. 288-298.
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© 2020, © 2020 Institute of Materials, Minerals and Mining Published by Taylor & Francis on behalf of the Institute. Here, a new class superhydrophobic surface based on nano-engineering was proposed and prepared to improve the durability of corrosion protect. Moreover, the durability of anticorrosion was evaluated by the Tafel polarization curves and electrochemical impedance spectroscopy under various damages of mechanical abrasion, chemical immersion and cool/thermal treatment. The superhydrophobic surface based on nano-engineering still showed excellent anticorrosion performance, such as low corrosion current (∼10−10 A cm−2), large polarization resistance (>150.0 MΩ cm2) and low corrosion rate (∼10−6 mm/year). The good durability was attributed to the special nano-engineering with low surface roughness and surface energy. The work provides a new method to improve the durability of the superhydrophobic surfaces for application in anticorrosion technology.
Zhou, Y, Xu, X, Song, K, Yeerken, S, Deng, M, Li, L, Riya, S, Wang, Q & Terada, A 2021, 'Nonlinear pattern and algal dual-impact in N2O emission with increasing trophic levels in shallow lakes', Water Research, vol. 203, pp. 117489-117489.
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Shallow lakes are considered important contributors to emissions of nitrous oxide (N2O), a powerful greenhouse gas, in aquatic ecosystems. There is a large degree of uncertainty regarding the relationship between N2O emissions and the progress of lake eutrophication, and the mechanisms underlying N2O emissions are poorly understood. Here, N2O emission fluxes and environmental variables in different lakes along a trophic state gradient in the Yangtze River basin were studied. N2O emission fluxes were -1.0-53.0 μg m-2 h-1 and 0.4-102.9 μg m-2 h-1 in summer and winter, respectively, indicating that there was marked variation in N2O emissions among lakes of different trophic state. The non-linear exponential model explained differences in N2O emission fluxes by the degree of eutrophication (p < 0.01). TN and chl-a both predicted 86% of the N2O emission fluxes in shallow lakes. The predicted N2O emission fluxes based on the IPCC EF5r overestimated the observed fluxes, particularly those in hyper-eutrophic lakes. These findings demonstrated that nutrient-rich conditions and algal accumulation are key factors determining N2O emission fluxes in shallow lakes. Furthermore, this study also revealed that temperature and algae accumulation-decomposition determine an N2O emission flux in an intricate manner. A low temperature, i.e., winter, limits algae growth and low oxygen consumption for algae decomposition. The environment leaves a high dissolved oxygen concentration, slowing down N2O consumption as the final step of denitrification. In summer, with the oxygen consumed by excess algal decomposition, the N2O production is limited by the complete denitrification as well as the limited substrate supply of nitrate by nitrification in hypoxic or anoxic conditions. Such cascading events explained the higher N2O emission fluxes from shallow lakes in winter compared with summer. This trend was amplified in hyper-eutrophic shallow lakes after algal disappearance. Collect...
Zhu, P, Pan, X, Li, X, Liu, X, Liu, Q, Zhou, J, Dai, X & Qian, G 2021, 'Biodegradation of plastics from waste electrical and electronic equipment by greater wax moth larvae (Galleria mellonella)', Journal of Cleaner Production, vol. 310, pp. 127346-127346.
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Disposal of the increasing amount of the plastics from waste electrical and electronic equipment (WEEE) is of great concern. In this study, biodegradation feasibility of waste rigid polyurethane (WRPU), waste polystyrene (WPS) and waste acrylonitrile-butadiene-styrene (WABS) from WEEE by Galleria mellonella larvae were investigated. The cumulative consumptions of WRPU, WPS and WABS are 35.08%, 13.41% and 4.87% of the total 2 g plastic within 7 d, respectively. TG-MS shows a decrease in the total weight loss and the changes of weight loss stages, implying that thermal stabilities of the three plastics drop. Meanwhile, Mn and Mw of the WPS and WABS decrease after the digestion, suggesting the depolymerization and biodegradation of the plastics. Fluorescence imaging demonstrates that total fluorescence intensity of the WRPU has a considerable decrease from 5.904 × 109 to 5.140 × 109 after digestion by Galleria mellonella larvae for 24 h. High-throughput sequencing reveals that the relative abundance of Enterococcus in the WABS and WPS groups increases and Enterobacter decreases, while WRPU shows the opposite trend. The findings suggest active adaptability of intestinal microbes to WEEE plastics with different properties, indicate the feasibility of Galleria mellonella larvae biodegrading the WEEE plastics, and provide a new potential biological treatment for WEEE plastics.
Zhu, P, Shen, Y, Pan, X, Dong, B, Zhou, J, Zhang, W & Li, X 2021, 'Reducing odor emissions from feces aerobic composting: additives', RSC Advances, vol. 11, no. 26, pp. 15977-15988.
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Aerobic composting is a reliable technology for treating human and animal feces, and converting them into resources. The addition of additives can reduce the production of odor during the composting process.
Zhu, Y, Zhong, H, Wang, H, Ouyang, L, Liu, J, Huang, Z & Zhu, M 2021, 'Breaking the Passivation: Sodium Borohydride Synthesis by Reacting Hydrated Borax with Aluminum', Chemistry – A European Journal, vol. 27, no. 35, pp. 9087-9093.
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AbstractA significant obstacle in the large‐scale applications of sodium borohydride (NaBH4) for hydrogen storage is its high cost. Herein, we report a new method to synthesize NaBH4 by ball milling hydrated sodium tetraborate (Na2B4O7 ⋅ 10H2O) with low‐cost Al or Al88Si12, instead of Na, Mg or Ca. An effective strategy is developed to facilitate mass transfer during the reaction by introducing NaH to enable the formation of NaAlO2 instead of dense Al2O3 on Al surface, and by using Si as a milling additive to prevent agglomeration and also break up passivation layers. Another advantage of this process is that hydrogen in Na2B4O7 ⋅ 10H2O serves as a hydrogen source for NaBH4 generation. Considering the low cost of the starting materials and simplicity in operation, our studies demonstrate the potential of producing NaBH4 in a more economical way than the commercial process.
Zou, L, Song, L, Li, M, Wang, X, Huang, X, Zhang, Y, Dong, B, Zhou, J & Li, X 2021, 'Differential Effect of Anaerobic Digestion on Gaseous Products from Sequential Pyrolysis of Three Organic Solid Wastes', ACS Omega, vol. 6, no. 34, pp. 22103-22113.
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Studies have shown that anaerobic digestion (AD) has an effect on the liquid and solid product property of sequential pyrolysis, but its influence on the gaseous products is lacking. In this study, syngas produced by pyrolysis from three raw organic solid wastes and the corresponding digestates, i.e., food waste, vinasse, and cow manure were investigated. AD causes a decrease in the contents of volatile solid, fixed carbon, C, H, and N and an increase in the S content. The weight loss of the wastes mainly occurs at 200–550 °C during the pyrolysis and the loss of the food waste and vinasse is higher than that of cow manure. In the carbon (C)-containing gas, AD leads to a decrease in the CH4 content of the syngas, implying that the heat values of the digestates are lower than that of the raw substrates. After AD, the total amount of nitrogen (N)-containing gas from the vinasse increases by 40.1%, while that from cow manure decreases by 14.1%. On the contrary, the total amount of sulfur (S)-containing groups in the syngas from vinasse drop by 22.0%, while that from cow manure increases by 9.1%. In addition, slight changes in the C-, N-, and S-containing gases are found from food waste. The results indicate that AD has a different effect on the N- and S- containing gaseous groups from different organic solid wastes, and the mechanisms deserve further investigation. The findings supply a theoretical foundation for environmental-friendly application of syngas from the digestates.
Zuo, L, Yao, H, Li, H, Jia, F, Wei, W, Liu, Y, Ni, B-J & Chen, X 2021, 'Modeling of completely autotrophic nitrogen removal process with salt and glycine betaine addition', Chemosphere, vol. 264, no. Pt 2, pp. 128474-128474.
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The susceptibility of the completely autotrophic nitrogen removal over nitrite (CANON) process to high salinity limits its widespread application. The addition of glycine betaine (GB), a type of compatible solutes that could resist osmotic stress, could be an effective strategy to enhance the salt tolerance ability of aerobic and anaerobic ammonium oxidizing bacteria (AOB and anammox bacteria) involved in the CANON process. This study aims to make use of mathematical modeling to systematically investigate the effects of salt and GB addition on the activities of AOB and anammox bacteria and the treatment performance of the CANON process. To this end, a series of dedicated batch tests and long-term experiments for the CANON process with salt and GB additions were conducted and the data was used to calibrate and validate the model established to consider the relationships between salt and GB concentrations and bacterial growth in the CANON process. The calibrated/validated CANON process model was then applied to simulate the long-term impacts of GB addition concentration and sludge retention time (SRT) on the CANON process. The results showed that 1 mM GB addition and a SRT of 50 days would be sufficient to protect AOB and anammox bacteria under the high salinity (30 g/L NaCl) conditions studied and therefore reduce the time needed to recover the treatment performance of the CANON process from exposure to salt inhibition by 35%-40%.
