ZIF‐8 membrane synthesized via covalent‐assisted seeding on polyimide substrate for pervaporation dehydration

Abstract

Abstract In this study, a novel covalent‐assisted seeding method is developed to fabricate well‐intergrown ZIF‐8 membrane on polyimide (PI) substrate with imidazole‐2‐carboxaldehyde (ICA) as the covalent agent between ZIF‐8 layer and PI substrate. Compared to ethylenediamine‐crosslinked PI membrane and ZIF‐8/PI membrane synthesized without covalent‐assisted seeding method, ZIF‐8/PI membrane synthesized with ICA covalent‐assisted seeding method shows improved pervaporation performance for isopropanol dehydration. Subsequent surface coating with polydimethylsiloxane or polydopamine is applied to mitigate the grain boundary of ZIF‐8/PI membrane, which results in a further performance enhancement. The morphologies and physicochemical properties of the resultant membranes are characterized by scanning electron microscope, attenuated total reflectance‐Fourier transform infrared, X‐ray diffraction, and water contact angle. The effect of operation temperature on the separation performance is also carried out. This work demonstrates the novel covalent‐assisted seeding method for the preparation of ZIF‐8 membrane with high‐performance, which may hold a great potential for various ZIF membranes separation applications.