Enhanced antifouling performance of anion exchange membrane via in-situ constructed interfacial polymerization modified layer within electrodialysis stack

Organic fouling of anion exchange membranes (AEMs) severely limits the large-scale application of electrodialysis (ED) in industrial wastewater resource recovery, primarily due to the compromised engineering feasibility of ex-situ modifications requiring stack disassembly. To address this, we developed an efficient strategy enabling in-situ directional construction of an interfacial polymerization (IP) modified layer within ED stacks, significantly enhancing AEM antifouling performance. This approach leverages direct-current electric field to directionally deposit tannic acid (TA) onto AEM surfaces, followed by injection of trimesoyl chloride (TMC) to initiate polymerization, enabling in-situ constructing of IP-modified layers. Optimized conditions yielded [email protected] g/L-AEM (TMC: 1.0 g/L) with maximized esterification degree and surface charge density (−31.25 mV), exhibiting superior antifouling performance. In sodium dodecyl sulfonate (SDS) fouling tests, [email protected] g/L maintained 24.29% higher desalination rate than pristine membrane stacks at 120 min and exhibited exceptional operational stability (>1200 min). Mechanistic analysis revealed that the in-situ IP-modified layer synergistically suppresses foulant aggregation in the diffusion boundary layer through enhanced surface negative charge density and stability compared to solely electrodeposited TA. This work provides a scalable approach for in-situ construction of modified layers within ED stacks.