In-situ cross-linked porous anion exchange membranes with high performance for efficient acid recovery

Diffusion dialysis (DD) has high economic competitiveness for acid recovery; however, the fabrication of highly acid-permeable and salt-rejecting anion exchange membranes (AEMs) for DD is still a grand challenge. This paper presents in-situ cross-linked porous AEMs with tunable microstructures and high DD performance. The AEMs were fabricated based on chloromethyl polyethersulfone substrate using N, N, N′, N″, N″-pentamethyldiethylenetriamine as a bifunctional agent for cross-linking and quaternization. The prepared porous AEMs showed significantly superior DD performance over conventional dense AEMs due to the high free volume and cross-linked networks within our membranes. The acid dialysis coefficient (UH+) and acid/salt separation factor (S) of the optimal AEM were 2.6 and 255.4 times as high as those of the commercial DF-120 AEM, respectively. Therefore, our low-cost, high-performance in-situ cross-linked porous AEMs may pave the way for large-scale acid recovery applications.