The cationic covalent organic frameworks (COFs) with editable pore environment and pore size are promising candidates for constructing the ion channel of anion exchange membranes (AEMs) with excellent separation properties, but the high reversible linking bond (e.g. imine) makes these membranes unstable in the industrial applications. In this work, the keto-linked COF (TpTG_Cl) with high acid-stability was fabricated on the surface of carboxyl-modified polyacrylonitrile (CPAN) ultrafiltration membrane. The COF active layer with positively charged property in pore channels afforded high separation factor of H⁺/Fe²⁺ up to 450 under batch dialysis process. Owing to the electrostatic repulsion, the cationic nanopore demonstrated a screening feature that transmitted H⁺ and rejected Fe²⁺. Moreover, the membranes (TpTG_Cl/CPAN) exhibited outstanding acid-stability, which could maintain high separation performance after 10 cycle under strong-acid conditions. The result suggested that COF with chemical stability and functional embellishment offered opportunities to synthesis high performance ion exchange membrane, and it could further be leveraged to tackle other challenges in membrane separation field.

具有可编辑孔环境和孔径的阳离子共价有机骨架 (COF) 是构建具有优异分离性能的阴离子交换膜 (AEM) 离子通道的有希望的候选者，但高度可逆的连接键（例如亚胺）使这些膜在工业应用。在这项工作中，在羧基改性聚丙烯腈（CPAN）超滤膜的表面上制备了具有高酸稳定性的酮联COF（TpTG _Cl）。孔道中带正电荷的COF活性层提供了高的H ⁺ /Fe ²⁺分离因子高达 450 在批量透析过程中。由于静电排斥，阳离子纳米孔表现出传输H ⁺和排斥Fe ²⁺的筛选特征。此外，膜（TpTG _Cl /CPAN）表现出优异的酸稳定性，在强酸条件下循环10次后仍能保持较高的分离性能。结果表明，具有化学稳定性和功能修饰的 COF 为合成高性能离子交换膜提供了机会，并且可以进一步利用它来应对膜分离领域的其他挑战。