Dual Functional Layers Modified Anion Exchange Membranes with Improved Fouling Resistant for Electrodialysis

Abstract The fouling mitigation of anion exchange membrane (AEM) performance is a great challenge faced by many membrane applications (e.g., electrodialysis, ED). In this study, a novel AEM is modified with dual functional layers prepared by coating hydrophilic polydopamine (PDA) on quaternized poly(2,6‐dimethyl‐1,4‐phenylene oxide), and subsequently grafting with zwitterionic structure of sulfobetaine methacrylate via the aza‐Michael reaction, aiming to improve the membrane fouling resistant. In particular, the sodium dodecyl benzene sulfonate (SDBS) is used as model foulant. The hydrophilic layer (PDA) and hydrophilic/negatively charged zwitterionic surface of AEM, act as useful barriers via physical blocking and electrostatic repulsion, respectively. The proposed modification can restrict the deposition and/or chemical adsorption of SDBS. The time elapsed until the occurrence of fouling (transition time) is significantly enhanced as result of modification (around five times longer) as evidence of the reinforced antifouling property. The enhanced performance of modified membrane is also confirmed by desalting experiments in terms of NaCl rejection potential. The facile preparation and advanced performances of dual functional layers modified AEM suggest its potential ED application.