Study of effect of two sulfonating agents on electrochemical properties of surface‐modified polyethersulfone membrane

Abstract

The work deals with the selection of sulfonating agent and preparation of polymeric coating on membrane step by step. The surface modification of a commercial ultrafiltration polyethersulfone (PES) membrane was covalently attached to the poly(styrene‐co‐divinylbenzene‐co‐4‐vinylbenzylchloride). The whole process was tracked step by step using analytical methods. Chlorosulfonic acid and trimethylsilyl chlorosulfonate were tested as sulfonating agents. Ion‐exchange capacity (IEC), water content, specific resistance, and permselectivity were measured and scanning electron microscope analyzed the surface of the cation exchange membrane. The best results were achieved using 5 wt % chlorosulfonic acid as sulfonating agent. IEC reached values of up to 2.44 meq g−1 of dry matter, permselectivity of 93.6%, area resistances of 10.1 Ω cm2, and specific resistance around 299 Ω cm. The prepared cation exchange PES membrane with chlorosulfonic acid can be used in electrochemical processes, for example, in electrodialysis. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48826.