In-situ growth of highly permeable zeolite imidazolate framework membranes on porous polymer substrate using metal chelated polyaniline as interface layer

Abstract

A facile and simple chelation assisted in-situ growth approach for the preparation of thin uniform metal organic framework composite membranes has been developed. Coherent zeolite imidazolate framework ZIF-7 and ZIF-67 layers were successfully grown on porous polypropylene substrate covered with metal-chelating polyaniline interface layer. These membranes exhibited a H2 permeance of 1.6 × 10−7 mol m−2 s−1 Pa−1 and an ideal H2/CO2 separation factor of 7.9. The incorporation of the second organic linker 2-aminobenzimidazole in the ZIF-7 framework afforded ZIF-7-NH2 layer enabling gate-opening and flexibility. This new hybrid ZIF-7-NH2 membrane featured a significantly increased H2 permeance of 4.9 × 10−6 mol m−2 s−1 Pa−1 and an ideal H2/CO2 separation factor of 10.6.