Zwitterionic polymer brush functionalized graphene oxide blended polyethersulfone membrane with enhanced performance and anti-biofouling properties

Biofouling still poses a significant challenge to membrane-based water treatment as it compromises water flux, increases energy consumption, and reduces membrane life. Zwitterion-based polymer brushes have recently received a great deal of attention as prospective anti-biofouling materials. This study explored the efficacy of grafting zwitterionic polymer brushes on Graphene oxide (GO) blended Poly-ether sulfone (PES) membrane to develop better-performing ultrafiltration (UF) membranes with enhanced anti-biofouling potential. These GO-blended PES membranes were modified by surface-initiated atom transfer radical polymerization (SI-ATRP) to graft poly[2-(methacryloyloxy) ethyl dimethyl-(3-sulfopropyl) ammonium hydroxide] (pMEDSAH) zwitterionic brushes to the membrane surface. The pMEDSAH grafting has improved the hydrophilicity and provided smoother topology to the surface. Compared to the pristine PES membrane, the pMEDSAH grafted GO-PES membrane (PES-GO-PB) showed better performance with an increase in water flux and improvement in BSA rejection. In dynamic biofouling experiments using Escherichia coli, similar to 90% decrease in the live biomass for polymer brushes-modified membrane was observed. The water flux recovery has also been enhanced for the PES-GO-PB membrane. Finally, the relation between ATRP reaction time and membrane performance was also explored, and the result suggested that membrane porosity acts as a key factor.