Enhancing anti-biofouling activity in electrodialysis by spraying GO@Ag nanosheets on anion exchange membranes

To mitigate biofouling and maintain the properties of the anion exchange membranes (AEMs) in electrodialysis (ED) processes, conferring specialized functional coatings onto surfaces has proven effective in reducing susceptibility to biofouling. In this research, AEM substrates were synthesized using the conventional chemical assembly method, involving the reaction of 1-butylimidazole (BIm) with commercially available bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO). Subsequently, a synergistic anti-biofouling system comprising graphene oxide (GO) and Ag nanoparticles (NPs) co-mingled casting-solution was formulated into a 2-μm coating through spraying onto the AEM surface. Exceptional static antibacterial activity of this system towards prevalent Gram-negative ( E. coli ) and Gram-positive ( S. aureus ) bacteria due to contact killing mechanisms. The dynamic anti-biofilm capability of post-electrodialysis AEM was evaluated using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), revealing consistent efficacy. Notably, the enhancement of anti-biofouling properties was achieved without compromising separation efficiency, as the coating solution shares the same composition as the substrate membrane. Crucially, the co-sprayed coating technique on the AEM surface overcomes the conventional “trade-off phenomenon” between performance and stability. This approach to fabricating anti-biofouling AEMs is believed to provide valuable insights for further optimization and application, thereby facilitating their deployment in water treatment and related fields.