New types of graphene-based membranes with molecular sieve properties for He, H2 and H2O

Graphene oxide (GO) and graphene membranes were fabricated by dip-coating a GO dispersion on a specially designed 8YSZ mesoporous membrane. With the use of a reductive thermal treatment at 750 degrees C, it was possible to obtain a graphene membrane with permselectivities of 215, 80 and 170, for the gas pairs He/N-2, H-2/CO2 and H-2/N-2, respectively, and the H-2 permeance reached similar to 7 center dot 10(-8) mol m(-2) s(-1) Pa-1. High H2O permeance and selectivity was achieved by processing a GO membrane in air at 300 degrees C. In pervaporation with H2O/IPA mixtures (5% H2O), the resulting membrane selectively separated H2O (separation factor > 800) and a flux of 4-8 kg m(-2) h(-1) was achieved at 70 degrees C.