Other affiliations: University of California, Los Angeles, Nanyang Technological University, National University of Singapore
Bio: Xue Jin is an academic researcher from University of Glasgow. The author has contributed to research in topics: Membrane fouling & Membrane. The author has an hindex of 17, co-authored 22 publications receiving 2208 citations. Previous affiliations of Xue Jin include University of California, Los Angeles & Nanyang Technological University.
TL;DR: In this article, the authors investigated the effects of operating conditions (feed and draw solution concentration, membrane type, membrane orientation, and temperature) and reverse solute diffusion on pressure retarded osmosis (PRO) performance using commercially available osmotic membranes.
Abstract: Pressure retarded osmosis (PRO) is a potential technology to harvest the renewable osmotic power from the salinity-gradient resources. This study systematically investigated the effects of operating conditions (feed and draw solution concentration, membrane type, membrane orientation, and temperature) and reverse solute diffusion on PRO performance using commercially available osmotic membranes. The PRO performance was improved by decreasing the feed solution concentration, increasing the draw solution concentration, orientating the membrane with active layer facing draw solution (AL-DS), and increasing temperature. The membrane with higher water permeability, lower solute permeability and lower structure parameter performed better in PRO process. However, the experimentally obtained power densities for all the membranes used in this study were lower than the predictions from conventional ICP model that assumes membrane separation parameters are constant in PRO process. It was found that this was mainly caused by the severe reverse solute diffusion and thus the enhanced internal concentration polarization (ICP) in PRO. The specific reverse solute flux was found to increase with increasing the applied hydraulic pressure, but the increase of experimental results was much more drastic than the theoretic prediction especially under higher hydraulic pressure, probably due to the increased solute permeability caused by membrane deformation.
TL;DR: Fetal bovine serum (FBS) was an effective dispersing agent for TiO(2) nanoparticles in all six media due to synergistic effects of its multiple protein components, successfully reproduced using a simple "FBS mimic" protein cocktail containing similar concentrations of BSA, γ-globulin, and apo-transferrin.
Abstract: Accurate evaluation of engineered nanomaterial toxicity requires not only comprehensive physical-chemical characterization of nanomaterials as produced, but also thorough understanding of nanomaterial properties and behavior under conditions similar to those used for in vitro and in vivo toxicity studies. In this investigation, TiO(2) nanoparticles were selected as a model nanoparticle and bovine serum albumin (BSA) was selected as a model protein for studying the effect of protein-nanoparticle interaction on TiO(2) nanoparticle dispersion in six different mammalian, bacteria, and yeast cell culture media. Great improvement in TiO(2) dispersion was observed upon the addition of BSA, even though the degree of dispersion varied from medium to medium and phosphate concentration in the cell culture media was one of the key factors governing nanoparticle dispersion. Fetal bovine serum (FBS) was an effective dispersing agent for TiO(2) nanoparticles in all six media due to synergistic effects of its multiple protein components, successfully reproduced using a simple "FBS mimic" protein cocktail containing similar concentrations of BSA, γ-globulin, and apo-transferrin.
TL;DR: These simple, but systematic studies--enabled by high-throughput screening--reveal the inherent complexity associated with understanding silver nanoparticle antibacterial efficacy as well as potential environmental impacts of silver nanoparticles.
Abstract: Although silver nanoparticles are being exploited widely in antimicrobial applications, the mechanisms underlying silver nanoparticle antimicrobial properties in environmentally relevant media are not fully understood. The latter point is critical for understanding potential environmental impacts of silver nanoparticles. The aim of this study was to elucidate the influence of inorganic aquatic chemistry on silver nanoparticle stability (aggregation, dissolution, reprecipitation) and bacterial viability. A synthetic “fresh water” matrix was prepared comprising various combinations of cations and anions while maintaining a fixed ionic strength. Aggregation and dissolution of silver nanoparticles was influenced by electrolyte composition; experimentally determined ionic silver concentrations were about half that predicted from a thermodynamic model and about 1000 times lower than the maximum dispersed silver nanoparticle concentration. Antibacterial activity of silver nanoparticles was much lower than Ag+ io...
TL;DR: High-throughput screening was used to elucidate ZnO nanoparticle stability, bioavailability, and antibacterial mechanisms as a function of iron doping level, aquatic chemistry, and bacterial cell type, and results underscore the complexities and challenges regulators face in assessing potential environmental impacts of nanotechnology.
Abstract: The stability and bioavailability of nanoparticles is governed by the interfacial properties that nanoparticles acquire when immersed in a particular aquatic media as well as the type of organism or cell under consideration. Herein, high-throughput screening (HTS) was used to elucidate ZnO nanoparticle stability, bioavailability, and antibacterial mechanisms as a function of iron doping level (in the ZnO nanoparticles), aquatic chemistry, and bacterial cell type. ζ-Potential and aggregation state of dispersed ZnO nanoparticles was strongly influenced by iron doping in addition to electrolyte composition and dissolved organic matter; however, bacterial inactivation by ZnO nanoparticles was most significantly influenced by Zn2+ ions dissolution, cell type, and organic matter. Nanoparticle IC50 values determined for Bacillus subtilis and Escherichia coli were on the order of 0.3−0.5 and 15−43 mg/L (as Zn2+), while the IC50 for Zn2+ tolerant Pseudomonas putida was always >500 mg/L. Tannic acid decreased toxic...
TL;DR: This study systematically investigated the alginate fouling on an osmotic membrane during FO operation using four types of draw solutions to elucidate the relationships between reverse (from draw solution to feed solution) and forward (from feed solution to draw solution) solute diffusion, and membrane fouling.
Abstract: Osmotically driven membrane processes, such as forward osmosis (FO) and pressure retarded osmosis (PRO), are attracting increasing interest in research and applications in environment and energy related fields. In this study, we systematically investigated the alginate fouling on an osmotic membrane during FO operation using four types of draw solutions (NaCl, MgCl2, CaCl2 and Ca(NO3)2) to elucidate the relationships between reverse (from draw solution to feed solution) and forward (from feed solution to draw solution) solute diffusion, and membrane fouling. At the same water flux level (achieved by adjusting the draw solution concentration), the greatest reverse solute diffusion rate was observed for NaCl draw solution, followed by Ca(NO3)2 draw solution, and then CaCl2 draw solution and MgCl2 draw solution, the order of which was consistent with that of their solute permeability coefficients. Moreover, the reverse solute diffusion of draw solute (especially divalent cation) can change the feed solution chemistry and thus enhance membrane fouling by alginate, the extent of which is related to the rate of the reverse draw solute diffusion and its ability to interact with the foulant. The extent of fouling for the four types of draw solution followed an order of Ca(NO3)2 > CaCl2 >> MgCl2 > NaCl. On the other hand, the rate of forward diffusion of feed solute (e.g., Na+) was in turn promoted under severe membrane fouling in active layer facing draw solution orientation, which may be attributed to the fouling enhanced concentration polarization (pore clogging enhanced ICP and cake enhanced concentration polarization). The enhanced concentration polarization can lead to additional water flux reduction and is an important mechanism governing the water flux behavior during FO membrane fouling. Findings have significant implications for the draw solution selection and membrane fouling control in osmotically driven membrane processes.
TL;DR: This review critically assesses the contributions of carbon-based nanomaterials to a broad range of environmental applications: sorbents, high-flux membranes, depth filters, antimicrobial agents, environmental sensors, renewable energy technologies, and pollution prevention strategies.
Abstract: The unique and tunable properties of carbon-based nanomaterials enable new technologies for identifying and addressing environmental challenges. This review critically assesses the contributions of carbon-based nanomaterials to a broad range of environmental applications: sorbents, high-flux membranes, depth filters, antimicrobial agents, environmental sensors, renewable energy technologies, and pollution prevention strategies. In linking technological advance back to the physical, chemical, and electronic properties of carbonaceous nanomaterials, this article also outlines future opportunities for nanomaterial application in environmental systems.
TL;DR: In this paper, a review of the recent developments in forward osmosis (FO) focusing on the opportunities and challenges is presented, as well as a clear outline for FO-concerned researchers.
Abstract: Recently, forward osmosis (FO) has attracted growing attention in many potential applications such as power generation, desalination, wastewater treatment and food processing. However, there are still several critical challenges, including concentration polarization, membrane fouling, reverse solute diffusion and the need for new membrane development and draw solute design in FO. These challenges are also the current research focus on FO. This paper aims to review the recent developments in FO, focusing on the opportunities and challenges. It begins with discussing the advantages of the FO process over pressure-driven membrane processes. These potential advantages lie in FO's low energy consumption, low fouling propensity, reduced or easy cleaning, low costs, high salt rejection and high water flux. Next, the recent applications of FO, as the outcomes of the above advantages, are described. The key part of this review is a detailed discussion of five critical challenges faced by FO and their relationships. Finally, the future of FO is viewed. This review provides a clear outline for FO-concerned researchers on the recent developments in FO.
TL;DR: An attempt has been made in this paper to review As contamination, its effect on human health and various conventional and advance technologies which are being used for the removal of As from soil and water.
Abstract: The exposure to low or high concentrations of arsenic (As), either due to the direct consumption of As contaminated drinking water, or indirectly through daily intake of As contaminated food may be fatal to the human health. Arsenic contamination in drinking water threatens more than 150 millions peoples all over the world. Around 110 millions of those peoples live in 10 countries in South and South-East Asia: Bangladesh, Cambodia, China, India, Laos, Myanmar, Nepal, Pakistan, Taiwan and Vietnam. Therefore, treatment of As contaminated water and soil could be the only effective option to minimize the health hazard. Therefore, keeping in view the above facts, an attempt has been made in this paper to review As contamination, its effect on human health and various conventional and advance technologies which are being used for the removal of As from soil and water.
TL;DR: In this article, the authors used alginate as a model organic foulant to examine forward osmosis (FO) membrane fouling and cleaning behavior with the ultimate goal of determining the underlying FO fouling/cleaning mechanisms.
Abstract: The recently resurgent forward osmosis (FO) membrane process has the potential to become a sustainable alternative to conventional membrane processes. However, the fouling and cleaning behavior of FO membranes remains largely unknown. There is a need to fully understand the fouling phenomena in FO in order to take advantage of this emerging technology. In this study, we used alginate as a model organic foulant to examine FO membrane fouling and cleaning behavior with the ultimate goal of determining the underlying FO fouling/cleaning mechanisms. Results showed that alginate fouling in FO is almost fully reversible, with more than 98% recovery of permeate water flux possible after a simple water rinse without any chemical cleaning reagents. We also studied the role of applied hydraulic pressure in membrane fouling and cleaning by performing fouling tests in FO (without hydraulic pressure) and RO (with hydraulic pressure) modes. Flux recovery in the FO mode was much higher than that in the RO mode under similar cleaning conditions, although the rate of membrane flux decline was similar in the two modes. The fouling reversibility of FO was attributed to the less compact organic fouling layer formed in FO mode due to the lack of hydraulic pressure. Our results suggest that operating in FO mode may offer an unprecedented advantage in reducing or even eliminating the need for chemical cleaning. AFM force measurements were used to elucidate the impact of membrane materials (cellulose acetate versus polyamide) on membrane fouling and cleaning behavior. Adhesion force data revealed that a small percentage of relatively adhesive sites on the membrane surface play an important role in increasing membrane fouling potential and decreasing cleaning efficiency. This finding implies that using average adhesion force to predict membrane fouling potential is inadequate. Extensive long-range adhesion forces are observed for the polyamide membrane in the presence of alginate and calcium ions. The long-range interactions are attributed to calcium bridging of alginate molecules between the AFM probe and the adhesive sites on the polyamide membrane surface.
TL;DR: In this paper, a review of polymeric membrane fabrication techniques for pressure driven membrane processes and membrane distillation is discussed, the fabrication technique, properties of the fabricated membranes and performance in water desalination are related.
Abstract: In this review, polymeric membrane fabrication techniques for pressure driven membrane processes and membrane distillation are discussed. The fabrication technique, properties of the fabricated membranes and performance in water desalination are related. Important parameters which affect the membrane performance such as crystallinity of the membrane based polymer, porous structure, hydrophobicity/hydrophilicity, membrane charge and surface roughness are analyzed. Despite the fact that extensive knowledge exist on how to ‘tailor’ membrane pore structure including its surface properties and cross-section morphology by selection of appropriate fabrication methods, there is still a challenge to produce reliable membranes with anti-fouling properties, chemical resistance, high mechanical strength with high flux and selectivity. To ensure progress in membrane performance, further improvements are needed of common membrane fabrication techniques such as phase inversion and interfacial polymerization. At the same time, the potential of novel fabrication techniques such as electrospinning and track-etching needs to be assessed. A comprehensive understanding between structure-surface properties and performance is a key for further development and progress in membrane technology for water desalination.