Highly Permeable Zeolite Imidazolate Framework-8 Membranes for CO 2 /CH 4 Separation

ZIF-8 membranes, a type of zeolite imidazolate framework, were synthesized by secondary seeded growth on tubular alpha-Al(2)O(3) porous supports. The presence of small, highly crystalline, microporous crystals with narrow particle size distribution led to continuous thin membranes. The synthesized novel ZIF-8 membranes displayed unprecedented high CO(2) permeances and relatively high separation indexes for equimolar mixtures of CO(2) and CH(4).