A pinboard by
Chunyan Xu

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.


Mitigation of Biofilm Development on Thin-Film Composite Membranes Functionalized with Zwitterionic Polymers and Silver Nanoparticles.

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