Zeolite Imidazolate Framework Membranes on Polymeric Substrates Modified with Poly(vinyl alcohol) and Alginate Composite Hydrogels.

Poly(vinyl alcohol)-sodium alginate composite hydrogels were first introduced to synthesize robust and well-intergrown zeolite imidazolate framework (ZIF)/polymer hollow fiber membranes. Through enough adsorption interaction with metal ions by chelation, sufficient nucleation sites for in situ metal-organic framework (MOF) preparation are provided. Using this method, we can not only easily prepare defect-free MOF membranes ignoring the complex modification process and seed deposition but also structurally fix crystalline MOF layers and greatly improve the stiffness and durability of MOF composite membranes. The strategy also gives the appropriate level of generality for synthesis of versatile dense MOF membranes on a variety of polymeric supports. The fabricated ZIF-8/polyethersulfone membrane presented remarkable gas separation performance with H2 permeance of as high as 9.66 × 10-7 mol m-2 s-1 Pa-1 and a high H2/CO2 separation factor of up to 29.0.