A durable and antifouling monovalent selective anion exchange membrane modified by polydopamine and sulfonated reduced graphene oxide

Developing a durable and antifouling monovalent selective anion exchange membrane is critical in practical electrodialysis (ED) process. Herein, a commercial anion exchange membrane was modified by sulfonated reduced graphene oxide (S-rGO) and polydopamine (PDA). Inspired by biological adhesion from mussels, the PDA coating on the surface of S-rGO-PDA membrane enhanced the stability of S-rGO nanosheets due to strong adhesion. The monovalent anion selectivity was evaluated by means of the Cl-/SO42- permeselectivity, and stability property was measured by the ion concentration changes of Cl- and SO42- for a long time application of ED. Moreover, antifouling property was measured by recording the time course of the potential difference in the presence of sodium dodecyl benzene sulfonate (SDBS). The results show that permselectivity of S-rGO-PDA membrane is 2.50, which is higher than pristine membrane (1.08). In addition, S-rGO-PDA membrane is stable, the permselectivity did not change significantly during 70 h ED process. Besides antifouling property of S-rGO-PDA membranes is improved compared with S-rGO membranes.