Modification of an anion exchange membrane based on rapid mussel-inspired deposition for improved antifouling performance

Abstract

In this study, an anion exchange membrane (AEM) was modified by rapid deposition of polydopamine (PDA) and 2,5-diaminobenzenesulfonic acid (DSA), where DSA was further immobilized by mussel-inspired PDA on the membrane surface. The surface properties of the AEM were characterized by a series of analysis techniques such as ATR-FTIR, XPS, AFM and SEM analysis, contact angle and zeta potential measurements. The results indicated that a uniform membrane surface was obtained by the rapid deposition of PDA/DSA complexes, which endowed the membrane with negative charge and higher hydrophilicity without significant increase of surface roughness. The rapid deposition of PDA/DSA complexes on the membrane surface improved significantly the antifouling performance of AEM to an organic foulant, i.e., sodium dodecyl sulfate (SDS) in electrodialysis. According to the change of the area electrical resistance after the fouling experiment, the antifouling performance of the modified AEM could be improved by 50.6 % under optimal modification parameter compared with the pristine AEM. The surface negative charge and higher hydrophilicity reduced the adsorption of organic foulants on the membrane and restricted the formation of a fouling layer on the membrane surface, hence contributed to the improvement of antifouling performance of the modified AEM.