Design of a novel poly(aryl ether nitrile)-based composite ultrafiltration membrane with improved permeability and antifouling performance using zwitterionic modified nano-silica

Abstract

Zwitterionic nano-silica (SiO2 NPs) obtained by lysine surface modification was used as a hydrophilic inorganic filler for preparing a poly(aryl ether nitrile) (PEN) nanocomposite membrane via an immersion precipitation phase inversion method. The effects of zwitterionic SiO2 NPs addition on the morphology, separation and antifouling performance of the synthesized membranes were investigated. Zwitterionic surface modification effectively avoided the agglomeration of SiO2 NPs. The PEN/zwitterionic SiO2 NPs composite membranes exhibited improved porosity, equilibrium water content, hydrophilicity and permeability due to the introduction of hydrophilic SiO2 NPs in the casting solution, and the optimal pure water flux was up to 507.2 L m-2 h-1, while the BSA rejection ratio was maintained at 97.4%. A static adsorption capacity of 72.9 μg cm-2 and the FRR up to 85.3% in the dynamic antifouling experiment proved that the introduction of zwitterionic SiO2 NPs inhibited irreversible fouling and enhanced the antifouling ability of the PEN membrane.