Highly selective sieving of small gas molecules by using an ultra-microporous metal-organic framework membrane

Two tailor-made microporous metal-organic framework (MOF) membranes were successfully fabricated on nickel screens by secondary growth. The effect of pore structures on gas separation was examined by means of single and binary gas permeation tests. The MOF JUC-150 membrane with its ultramicropores showed marked preferential permeance to H-2 relative to other gas molecules. The selectivity factors of this membrane were 26.3, 17.1 and 38.7 for H-2/CH4, H-2/N-2 and H-2/CO2, respectively, at room temperature. To the best of our knowledge, these values represent unprecedentedly high separation selectivity among those for all MOF membranes reported to date. The JUC-150 membrane also shows high thermal stability and outstanding separation performance at a high temperature of 200 degrees C. The separation performance of these membranes persists even after more than 1 year exposure to air. The superiority of the tailored pore size, high selectivity for H-2 over other gases, significant stability and recyclability make these materials potential candidates for industrial H-2 recycling applications.