Xu, B, Zhou, JL, Altaee, A, Ahmed, MB, Johir, MAH, Ren, J & Li, X 2020, 'Improved photocatalysis of perfluorooctanoic acid in water and wastewater by Ga2O3/UV system assisted by peroxymonosulfate', CHEMOSPHERE, vol. 239.View/Download from: UTS OPUS or Publisher's site
Ye, Y, Ngo, HH, Guo, W, Liu, Y, Chang, SW, Dinh, DN, Ren, J, Liu, Y & Zhang, X 2019, 'Feasibility study on a double chamber microbial fuel cell for nutrient recovery from municipal wastewater', CHEMICAL ENGINEERING JOURNAL, vol. 358, pp. 236-242.View/Download from: UTS OPUS or Publisher's site
Ren, J, Woo, YC, Yao, M, Lim, S, Tijing, LD & Shon, HK 2019, 'Nanoscale zero-valent iron (nZVI) immobilization onto graphene oxide (GO)-incorporated electrospun polyvinylidene fluoride (PVDF) nanofiber membrane for groundwater remediation via gravity-driven membrane filtration', SCIENCE OF THE TOTAL ENVIRONMENT, vol. 688, pp. 787-796.View/Download from: UTS OPUS or Publisher's site
Ren, J, Yao, M, Woo, YC, Tijing, LD, Kim, J-H & Shon, HK 2019, 'Recyclable nanoscale zerovalent iron (nZVI)-immobilized electrospun nanofiber composites with improved mechanical strength for groundwater remediation', COMPOSITES PART B-ENGINEERING, vol. 171, pp. 339-346.View/Download from: UTS OPUS or Publisher's site
Yao, M, Ren, J, Akther, N, Woo, YC, Tijing, LD, Kim, S-H & Shon, HK 2019, 'Improving membrane distillation performance: Morphology optimization of hollow fiber membranes with selected non-solvent in dope solution', CHEMOSPHERE, vol. 230, pp. 117-126.View/Download from: UTS OPUS or Publisher's site
Yao, M, Woo, YC, Ren, J, Tijing, LD, Choi, J-S, Kim, S-H & Shon, HK 2019, 'Volatile fatty acids and biogas recovery using thermophilic anaerobic membrane distillation bioreactor for wastewater reclamation.', Journal of environmental management, vol. 231, pp. 833-842.View/Download from: UTS OPUS or Publisher's site
The effects of bioreactor temperatures and salinities of an anaerobic membrane distillation bioreactor (anMDBR) on the permeation performance and their potential recovery of bioresources were fully examined in this study. To the best of our knowledge, this is the first study of a lab-scale anMDBR process utilizing sub-merged hollow fiber membranes. The hybrid system utilizing both membrane distillation (MD) and anaerobic bioreactors achieved 99.99% inorganic salt rejection regardless the operation temperatures and high initial flux from (2-4 L m-2 h-1) at 45-65 °C. However, after 7-day operation, the flux dropped by 16-50% proportional to the bioreactor temperatures. It was found that the effects of bioreactor temperatures had strong impacts on both the permeation performance and fouling behavior while salinity had insignificant effect. A compact non-porous fouling layer was observed on the membrane surface from the bioreactor operated at 65 °C while only a few depositions was found on the membrane from 45 °C bioreactor. In the present study, the optimal anMDBR temperature was found to be 45 °C, showing a balanced biogas production and membrane permeation performance including less fouling formation. At this bioreactor temperature (45 °C), the biogas yield was 0.14 L/g CODremoval, while maintaining a methane recovery of 42% in the biogas, similar recovery to those at bioreactor temperatures of 55 and 65 °C. The potential recovery of volatile fatty acids made anMDBR a more economically efficient system, in addition to its lower operation cost and smaller footprint compared with most other technologies for on-site wastewater treatment.
Ren, J, Tijing, LD & Shon, HK 2017, '"Robbing behavior" and re-immobilization of nanoscale zero-valent iron (nZVI) onto electrospun polymeric nanofiber mats for trichloroethylene (TCE) remediation', SEPARATION AND PURIFICATION TECHNOLOGY, vol. 189, pp. 375-381.View/Download from: UTS OPUS or Publisher's site
Ren, J, Tijing, LD & Shon, HK 2017, 'Effect of polymer ratio on nZVI loading onto Electrospun nanofiber mat for mitigating groundwater contaminants', TechConnect Briefs, vol. 2, pp. 265-268.View/Download from: UTS OPUS
Nanoscale zero-valent iron (nZVI) has been widely used for the reduction of halogenated organics and heavy metals in the groundwater. However, individual nZVI particles are mobile and prone to aggregate, thereby reducing the reaction sites exposed to contaminants. Electrospun polymer nanofiber mat is an ideal carrier to immobilize and distribute nZVI particles after its merits of high specific area, size-controllable and material-compatible properties. In this study, nZVI particles were loaded onto the polyacrylic acid (PAA)-polyvinyl alcohol (PVA) electrospun nanofiber mats with different PAA/PVA ratios. The results indicate that mat with the PAA/PVA ratio of 3:1 loaded the most nZVI particles (∼48 wt%) and had the highest removals to methylene blue at 94% and Cu (II) ions at 84% respectively. The nZVI-loaded electrospun nanofiber mat has promising application for the groundwater contaminants mitigation.
Ren, J, Woo, YC, Yao, M, Tijing, LD & Shon, HK 2017, 'Enhancement of nanoscale zero-valent iron immobilization onto electrospun polymeric nanofiber mats for groundwater remediation', Process Safety and Environmental Protection, vol. 112, no. Part B, pp. 200-208.View/Download from: UTS OPUS or Publisher's site
© 2017 Institution of Chemical Engineers A new approach that combines nanoscale zero-valent iron (nZVI) with electrospinning technology has been put forward to avoid nZVI agglomeration and a secondary pollution. In this study, to enhance the immobilization of nZVI particles onto the polyacrylic acid (PAA)/polyvinyl alcohol (PVA) electrospun nanofiber mat, mats (M1, M2 and M3) with different PAA/PVA mass ratios (1:1, 2:1 and 3:1) were tested for the immobilization of nZVI particles and their performance of removing contaminants. The results indicate that M3 immobilized the most nZVI particles (48.4 wt% on the mat, ∼2.5 times the figure for previous study) and had the highest removals to methylene blue and Cu(II) ions at 94% and 83.6% respectively, resulting from more free carboxylic groups available on the cross-linked nanofibers as well as a higher porosity into the mat. Therefore, increasing the PAA/PVA ratio is effective to boost the performance of nZVI–PAA/PVA electrospun nanofiber mat, which has a great potential for the application of nZVI-targeted contaminants remediation.
Ren, J, Li, X, Yang, Y, Liu, Y, Zhou, Z & Ji, S 2016, 'Effect of backwash temperature on hollow fiber ultrafiltration membranes fouled by sodium alginate', Desalination and Water Treatment, vol. 57, no. 8, pp. 3350-3357.View/Download from: Publisher's site
© 2014 Balaban Desalination Publications. All rights reserved. This study focuses on the effect of backwash temperatures (25, 40, and 55°C) on hollow fiber ultrafiltration membranes fouled by sodium alginate (SA). The results indicate that a higher backwash temperature could achieve a significant mitigation of total backwash resistance and a cleaning rate promotion. In the following cycle, the initial total fouling resistance was decreased with the temperature increase, while there was an undesirable increase on the fouling rate due to a higher SA concentration in the membrane pool. Although the membrane fouling resistance was more reversible, backwash at 55°C had a negative impact on the SA removal, because the functional gel layer was washed out. Moreover, all the beneficial effects from 25 to 40°C were more noticeable than those from 40 to 55°C. Overall, backwash at 40°C was relatively a better choice in this study.
Liu, Y, Li, X, Yang, Y, Ji, S, Ren, J & Zhou, Z 2015, 'Identification of the fouling-caused foulants with different pretreatments during ultrafiltration in polluted raw water', Desalination and Water Treatment, vol. 55, no. 11, pp. 2891-2899.View/Download from: Publisher's site
© 2014 Balaban Desalination Publications. All rights reserved. Abstract: Different pretreatments, including coagulation, adsorption, and biofiltration, were used to identify the useful pretreatment for the ultrafiltration of polluted raw water. The following prefiltration investigation was conducted to identify foulants that were responsible for membrane fouling. Organic removal and particle size distribution of different pretreated samples were measured. The results indicated that the concentration of organic matter was not the critical factor that determined the extent of flux decline. The turbidity relevant materials, such as colloids and particles, were supposed to be important fouling-caused substances, and the particle size distribution also had a significant influence on flux decline. Moreover, the fouling resistance of different prefiltrated samples showed that foulants sized over the membrane pore size caused the main part of the membrane fouling in raw water. Component analysis demonstrated that protein-like substances played a crucial role in membrane fouling; however, humic-like substances led to a weak membrane fouling.
Liu, Y, Li, X, Yang, Y, Ye, W, Ren, J & Zhou, Z 2015, 'Effect of ionic strength and calcium ions on humic acid fouling of hollow-fiber ultrafiltration membrane', Desalination and Water Treatment, vol. 54, no. 11, pp. 2976-2985.View/Download from: Publisher's site
© 2014 Balaban Desalination Publications. All rights reserved. Abstract: Effect of ionic strength and calcium ions addition on the molecular properties of humic acid (HA), as well as the HA rejection coefficient and fouling characteristics of ultrafiltration were investigated in this study. Experiments were performed with an immersed hollow-fiber polyvinyl chloride membrane at a laboratory scale. The results indicated that both ionic strength and calcium ions could effectively reduce zeta potential of the HA solution. Average size of HA was identical with various ionic strength (10, 20, and 40 mM) or low calcium ion concentration (0.5 mM), but a much larger HA size was obtained with higher calcium ion concentrations (1.0 mM or 2.0 mM) for the complexation interaction between HA molecules. The ionic strength significantly reduced the HA removal, and somewhat mitigated the membrane fouling for the reduction of electrostatic repulsive forces between HA molecules and the membrane surface. At a low calcium ion concentration, the surface complexation dominated the fouling behavior of the process, and led to an increase of cake fouling resistance. However, at higher calcium ion concentrations, the bulk complexation dominated the interaction fouling behavior of the process, leading to a reduction of both cake fouling and pore blocking for the larger size aggregations.
Zhou, Z, Yang, Y, Li, X, Su, Z, Liu, Y, Ren, J & Zhang, Y 2015, 'Effect of recycling filter backwash water on characteristic variability of dissolved organic matter in coagulation sedimentation process', Desalination and Water Treatment, vol. 53, no. 1, pp. 48-56.View/Download from: Publisher's site
© 2013, © 2013 Balaban Desalination Publications. All rights reserved. In this study, the physicochemical characteristics of the dissolved organic matter (DOM) in simulated raw water, corresponding filter backwash water (FBWW) and treated water at three recycling ratios of 2, 5, and 8%, including control without FBWW were evaluated using bulk properties, in addition to advanced characterization by molecular weight distribution (MWD), hydrophobicity, and fluorescence. The DOM characteristics of raw water and FBWW were primarily identified and compared, and it was found that DOM in FBWW was roughly hydrophilic as compared with raw water, and the FBWW was more refractory due to a substantial increment of low-MW (< 3 KDa). Additionally, humic-like fluorophore (Peak A) and protein-like fluorophore (Peak T1), with maxima at the Ex/Em wavelengths of 245.0–265.0 nm/400.0–435.0 nm, 280.0–305.0 nm/305.0–345.0 nm, respectively, were the two main components in raw water and FBWW. Recycling trial results indicated that DOM removal efficiencies were improved with comparison to control. Specifically, all chemical fractions except hydrophobic neutral could enhance removal, but MWD was highly depended on the physical nature of raw water and FBWW. Fluorescence spectra of treated water indicated recycling FBWW could effectively improve humic-like substance (Peak A) removal, but the protein-like matter (Peak T1) was resistant to elimination or was enriched.
Liu, Y, Li, X, Yang, Y, An, D, Ren, J, Zhou, Z, Jia, R & Song, W 2014, 'Effect of raw water and sedimentation effluent on fouling control of PAC/UF integrated process', Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology, vol. 46, no. 2, pp. 98-103.
To investigate the main factor that influenced membrane fouling in ultrafiltration, a simulated process of powdered activated carbon and ultrafiltration (PAC/UF) was used to treat micro-polluted raw water and the sedimentation effluent. Membrane fouling characteristics of two samples, effect of particle size and dissolved organic matter on membrane fouling were investigated. The results indicated that PAC/UF process could mitigate the membrane fouling of the sedimentation effluent, but it could not alleviate the membrane fouling of raw water. Organics in the raw water were mostly hydrophilic organic-based small molecules, and it could not mitigate the membrane fouling of the raw water although the aromaticity and the dissolved microbiological products were reduced with the adsorption of PAC particles, which indicated that the adsorbed organic did not cause serious membrane fouling in the raw water. The particles in raw water, with a small particle size and high number, was thought to be the main factor that leading to the invalid fouling control function of PAC/UF process on raw water. Particle number and particle size distribution have a critical role in membrane fouling.
Liu, Y, Li, X, Yang, Y, Liang, S, Liu, L & Ren, J 2014, 'Treatment of micro-polluted alga-rich water with PAC and ultrafiltration integrated process', Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology), vol. 45, no. 8, pp. 2928-2933.
An integrated process of powdered activated carbon (PAC) and ultrafiltration (UF) and the independent UF were conducted to treat a micro-polluted alga-rich water. Effects of the two treatments on pollutant and microcystin-LR removal, as well as fouling control of PAC, were investigated. The results indicate that both of the two processes can remove the chlorophyll-a effectively. The maturities of nitrosomonas group and nitrobacteria are about 15 d and 20 d, respectively. The removal efficiencies of DOC and UV254 for the PAC/UF are 32.7% and 23.8%, and those of the independent UF process are 11.5% and 15.0%. Therefore, PAC can effectively enhance the organic removal and the MC-LR removal increases from 18.5% to 43.0% with the PAC addition, Moreover, PAC can mitigate the membrane fouling of UF process of alga-rich water. The integrated process of biological powdered activated carbon and UF tends to be a both economical and efficient technology for the treatment of MC-LR.
Liu, Y, Li, X, Yang, Y, Ren, J, Luo, W, Lin, X & Li, G 2014, 'Treatment of micro-polluted water with PAC and ultrafiltration integrated process', Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology), vol. 45, no. 7, pp. 2517-2522.
An integrated process of powdered activated carbon (PAC) and ultrafiltration (UF) was used to treat a micro-polluted water. Effects of PAC dosages on turbidity, UV254 and CODMn removal, as well as membrane fouling were investigated. Effects of PAC retention-time on organic removal was conducted simultaneously. The results indicate that the effluent turbidity is under 0.1000 NTU, which could not be influenced by PAC dosage and the turbidity of influent. Organics removal is enhanced with the increase of PAC dosage at 10, 20 and 40 mg/L, but the performance of unit PAC mass is reduced. It could meet the demand of economics and effluent quality at the dosage of 10 mg/L PAC. Organics removal is decreased with the increase of PAC retention-time, and the decline is weaker at a higher dosage. Membrane fouling is reduced with PAC-UF process. A better trans-membrane pressure (TMP) recovery is received for sodium hypochlorite composite with acid or alkali during chemical cleaning.
Liu, Y, Li, X, Yang, Y, Ye, W, Ji, S, Ren, J & Zhou, Z 2014, 'Analysis of the major particle-size based foulants responsible for ultrafiltration membrane fouling in polluted raw water', Desalination, vol. 347, pp. 191-198.View/Download from: Publisher's site
This paper focused on the major particle-size based foulants responsible for membrane fouling of ultrafiltration in simulated surface water polluted by sewage discharge. The experiment was conducted with a sequential filtration process, pre-filtration steps removed specific foulants (1.2. μm, 0.45. μm, 100. kDa and 10. kDa) from raw water with different membranes, and followed filtration tests were performed to investigate the fouling caused by remaining foulants. Flux decline and specific fouling resistance of different fractioned substances were compared to identify the particle-size based foulants most responsible for membrane fouling. The normalized flux decline showed that foulants over 1.2. μm had limited influence on flux decline, but that the 100. kDa-0.45. μm fraction contributed a significant part. Results of specific fouling resistance revealed that the 100. kDa-0.45. μm fraction caused higher fouling resistance than other fractions with the same quality of organic matter, and this fraction was confirmed to be most closely related to protein-like substances. Component analysis demonstrated that protein-like substances played a crucial role in membrane fouling, whereas humic-like substances were of minor relevance. Standard blocking and cake filtration were major mechanisms of membrane fouling caused by pre-filtered water, independent of the pore size of fractionation membranes. © 2014 Elsevier B.V.
Liu, YW, Li, X, Yang, YL, Ren, JW, Wang, WQ & Zhou, ZW 2014, 'Effect of coagulation/adsorption pretreatment on ultrafiltration characteristics', Beijing Ligong Daxue Xuebao/Transaction of Beijing Institute of Technology, vol. 34, no. 6, pp. 638-643.
Two methods of coagulation and adsorption were used to pretreat a simulated micro-polluted ground water to study the relationship between ultrafiltration (UF) membrane and pollution levels of different water samples and analyze the effect of particles characteristics on flux decline. The experimental results indicate that powdered activated carbon could reduce the concentration of organics effectively, but the effect of wiping out turbidity is not obvious. Coagulation could reduce the turbidity of water effectively although it has low efficiency on organics removal. The coagulation pretreatment could improve the flux of raw water, but the adsorption has no influence on flux. The correlation fitting results of fouling index of turbidity and dissolved organic matter (DOC) show that fouling index of UF has an obvious correlation with turbidity, but no obvious correlation could be found with DOC concentration. The turbidity-causing pollutants are the major foulant under experimental condition. The colloidal and particles sized between 0.01 μm and 1.2 μm are the main pollutant which lead to flux decline, meanwhile, it is cumulatively on fouling index for turbidity-causing pollutants during UF process.