Fabrication of polyamide/zwitterion functionalized mesoporous silica nanofiltration membrane with highly enhanced antifouling performance

Abstract

BackgroundThe nanofiltration membrane plays an important role in wastewater treatment and desalination. Fabricating the hydrophilic separation layer is a good way to construct nanofiltration membranes with both high water flux and antifouling performance. MethodsThe chemical and physical structure of the membrane surface are optimized simultaneously to enhance its performance. Three kinds of zwitterions bearing different positively and negatively charged units are grated onto mesoporous silica (MS), then the functionalized MS nanoparticles are introduced into polyamide separation layer on porous polyethersulfone substrate to construct hybrid nanofiltration membranes. The influence of zwitterion functionalized MS on the structure and comprehensive performance of hybrid membranes is thoroughly investigated by experimental and computational means. Significant findingsThe existence of zwitterion functionalized MS overcomes the tradeoff effect between water flux and salt rejection. The hybrid membrane shows a high water flux of 334.0 L m − 2h − 1 MPa−1 and a superior flux recovery ratio of 94.1% against bovine serum albumin. The corrected zero-point binding energies of three kinds of zwitterions with water molecules are computed for the first time, the carboxybetaine methacrylate shows the highest energy of 36.99 kJ mol−1, explaining why the as-prepared hybrid membranes possess outstanding antifouling performance.