PhD student, Georgia Institute of Technology
Membrane has been used in desalination area for a couple years. It becomes the most promising method for desalination as it is a high efficient and environmental friendly way to purify water without chemical addition. However, how to scale up membrane desalination process is still a problem. When the membrane is made into a large piece, the deformation problem becomes more serious, which will decrease water flux and rejection at the same time. Also, membrane deformation will intensify membrane fouling as the structure becomes unstable. In recent years, nanoparticles and 2-D materials such as graphene has been added in membrane fabrication to improve membrane properties include anti-fouling property, mechanical strength and hydrophilicity. In my research, I mainly focus on analyze the influence of mechanical properties of nanoparticles and 2-D materials on membrane desalination performance. Nanoparticles such as TiO2, multiwall carbon nanotubes (MWCNT), and silver nanoparticles all can increase the mechanical properties of membranes. Also, 2-D materials such as graphene, graphene oxide and silicone have influence on the strength of membrane as well. For high pressure desalination process like nanofiltration, forward osmosis, reverse osmosis, membrane mechanical strength is crucial for desalination performance. Structure determines properties. So if we want to optimize membrane performance, we need to fully understand the relation between the addition of nanoparticles, 2-D materials and membrane mechanical strength. In my research, I will test membrane performance and use simulation to explain it in detail. Based on the theory that previous researchers have raised, I will add my own idea and put membrane desalination scale up process forward.
Abstract: By modifying existing methods for synthesizing polyaniline, a polyaniline polymer having a new constellation of material properties has been produced. The material properties of the polymeric compositions disclosed herein enhance the use of polyanilines in a wide variety of processes that use such materials, for example processes used in the formation of filtration membranes.
Pub.: 06 Oct '11, Pinned: 16 Aug '17
Abstract: Disclosed are compaction resistant thin film composite membranes having a porous polymeric support; a semi-permeable polymer film polymerized on the porous polymeric support; and particles, of a size in the range of microparticles and nanoparticles, dispersed in the porous polymeric support. Also disclosed are methods of making compaction resistant membranes by polymerizing a polymer film on a porous polymeric support with particles of a size in the range of microparticles and nanoparticles dispersed therein, the particles having been selected to improve flux flow characteristics over time of the semi-permeable membrane. Also disclosed are methods of purifying water using the disclosed membranes. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.
Pub.: 04 Oct '11, Pinned: 16 Aug '17
Abstract: Azide-functionalized graphene oxide (AGO) was covalently anchored onto commercial reverse osmosis (RO) membrane surfaces via azide photochemistry. Surface modification was carried out by coating the RO membrane with an aqueous dispersion of AGO followed by UV exposure under ambient conditions. This simple process produces a hydrophilic, smooth, antibacterial membrane with limited reduction in water permeability or salt selectivity. The GO-RO membrane exhibited a seventeen fold reduction in biofouling after 24 hours of E. coli contact and almost two times reduced BSA fouling after a one week cross-flow test compared to its unmodified counterpart.
Pub.: 28 May '16, Pinned: 16 Aug '17
Abstract: The separated NaOH and produced H2 in membrane processes can be recycled for the sustainable production of V2O5.Here, an energy-saving and efficient method is proposed for the clean and sustainable production of typical metal oxide (vanadium pentoxide as a case) by integrating diffusion dialysis with membrane electrolysis via cation-exchange membranes. This integrated process can achieve alkali recycle with less energy consumption. In addition, the gases—H2 and O2—produced in the membrane electrolysis process can be used as byproducts. Results indicate that the total alkali recovery ratio and the vanadium rejection ratio can be as high as ∼100% and ∼92.56%, respectively. Moreover, preliminary economic evaluation indicates that the running cost can be significantly decreased from $24.52/(m3 feed) (traditional method) to $–24.18/(m3 feed) (proposed method).
Pub.: 26 Apr '17, Pinned: 16 Aug '17
Abstract: We demonstrate the functionalization of thin-film composite membranes with zwitterionic polymers and silver nanoparticles (AgNPs) for combating biofouling. Combining hydrophilic zwitterionic polymer brushes and biocidal AgNPs endows the membrane with dual functionality: antiadhesion and bacterial inactivation. An atom transfer radical polymerization (ATRP) reaction is used to graft zwitterionic poly(sulfobetaine methacrylate) (PSBMA) brushes to the membrane surface, while AgNPs are synthesized in situ through chemical reduction of silver. Two different membrane architectures (Ag-PSBMA and PSBMA-Ag TFC) are developed according to the sequence AgNPs, and PSBMA brushes are grafted on the membrane surface. A static adhesion assay shows that both modified membranes significantly reduced the adsorption of proteins, which served as a model organic foulant. However, improved antimicrobial activity is observed for PSBMA-Ag TFC (i.e., AgNPs on top of the polymer brush) in comparison to the Ag-PSBMA TFC membrane (i.e., polymer brush on top of AgNPs), indicating that architecture of the antifouling layer is an important factor in the design of zwitterion-silver membranes. Confocal laser scanning microscopy (CLSM) imaging indicated that PSBMA-Ag TFC membranes effectively inhibit biofilm formation under dynamic cross-flow membrane biofouling tests. Finally, we demonstrate the regeneration of AgNPs on the membrane after depletion of silver from the surface of the PSBMA-Ag TFC membrane.
Pub.: 16 Dec '16, Pinned: 16 Aug '17
Abstract: In recent years, numerous large-scale seawater desalination plants have been built in water-stressed countries to augment available water resources, and construction of new desalination plants is expected to increase in the near future. Despite major advancements in desalination technologies, seawater desalination is still more energy intensive compared to conventional technologies for the treatment of fresh water. There are also concerns about the potential environmental impacts of large-scale seawater desalination plants. Here, we review the possible reductions in energy demand by state-of-the-art seawater desalination technologies, the potential role of advanced materials and innovative technologies in improving performance, and the sustainability of desalination as a technological solution to global water shortages.
Pub.: 06 Aug '11, Pinned: 16 Aug '17