The Revese-Selectivity of Nanoporous Membrane for the Separation of Gas Mixtures

Abstract

Abstract Membrane technology has attracted more and more attentions in oil/gas industries. Most of the membranes separation are based on the difference in molecular dimensions (or the mechanism of molecular sieving). However, this work reports the reverse-selectivity based on the permeation of binary gas mixtures (CO2/He and CO2/H2) through a nanoporous carbon molecular sieve membrane. It was found that adsorption-diffusion mechanism made it a possible for the nanoporous membrane to be selective to the lighter species (He or H2) or to the heavier CO2, possibly due to surface flux. The membrane permselectivity in this case is a function of the feed composition such that CO2 molecules can be preferentially permeated based on ‘surface flow’.