Toward improved antifouling properties and monovalent anion selectivity of anion exchange membrane via interfacial polymerization modification

Anion exchange membrane (AEM) with both antifouling properties and monovalent anion selectivity are crucial to promoting the widespread application of electrodialysis in industrial wastewater resourcing. In this study, interfacial polymerization (IP) modification AEMs with different structures were prepared by regulating the composition of aqueous monomers. Results show that the polyester modified layer with tannic acid (TA) as an aqueous phase monomer is more hydrophilic, and has the best negative charge density. The service life of the IPmodified AEM with TA as an aqueous phase monomer (TA-M) exceeds 200 % of pristine AEM (PM) in actual wastewater testing, and its selective separation efficiency in anion selectivity testing is over 10 times greater than that of PM. These results indicate that TA-M has improved antifouling properties and monovalent anion selectivity. According to in-situ electrochemical impedance spectroscopy results, the IP-modified layer of TA-M can not only avoid an obvious fouling layer formed due to concentration polarization but also attenuate the negative influence of sodium dodecylbenzene sulfonate on transmembrane migration of Cl-, thus improving the antifouling performance of AEM. Moreover, IP-modified layers form a new ion transfer interface during the transmembrane migration of SO42- to enhance the mass-transfer resistance, which determines the monovalent anion selectivity of AEM. This work provides valuable insights for constructing IP-modified layers on the AEM surface and promoting their application in the resourcing treatment of coking wastewater.