Enhanced permeability and antifouling properties of polyvinylidene fluoride ultrafiltration membrane with hydrophilic P(AMPS-co-MMA) copolymer

In this research, a new amphiphilic random copolymer of 2-acrylamido2-methylpropane sulfonic acid (AMPS) and methyl methacrylate (MMA) (abbreviated as P(AMPS-co-MMA)) was synthesized by solution free radical copolymerization method, and was introduced into hydrophobic polyvinylidene fluoride ( PVDF) membrane via nonsolvent induced phase separation ( NIPS) process without adding pore-forming agent to enhance the permeability and antifouling properties of PVDF ultrafiltration membrane. The FT-NMR spectroscopy confirmed the chemical structure of P(AMPS-co-MMA) and copolymerization of AMPS and MMA, the effects of P(AMPS-co-MMA) on membrane surface chemical compositions, morphology, roughness, charge, hydrophilicity, permeability and antifouling properties were characterized indetail. The results indicate that the PVDF/P(AMPS-co- MMA) composite membranes demonstrated excellent permeability, improved antifouling property and long- term stability due to the optimized membrane microstructure, stronger hydrophilicity and endowed negative charge. The PVDF composite membrane blended with 1.5 wt% P( AMPS-co-MMA) showed the best membrane performances, the pure water flux was 286.5 L.m(-2).h(-1) while the BSA rejection was as high as 98%, and the flux recovery ratio (FRR) and reversible fouling ratio to the total fouling ratio (R-r/R-t) reached 94.8% and 87% respectively, which outpaced ever reported and commercial PVDF membranes. Therefore, P(AMPS-co-MMA) copolymer was expected to be a potential excellent pore-forming material in fabricating high-performance membranes.

Automated summary

A new amphiphilic random copolymer (P(AMPS-co-MMA)) was synthesized and introduced into a hydrophobic PVDF membrane via the NIPS process. The effects of P(AMPS-co-MMA) on the membrane properties were studied in detail, and the composite membranes exhibited excellent permeability, improved antifouling property, and long-term stability. The PVDF composite membrane blended with 1.5 wt% P(AMPS-co-MMA) showed the best performance, with high water flux, BSA rejection, and flux recovery ratio.