Characterization of natural zeolite membranes for H2/CO2 separations by single gas permeation

Abstract

Natural zeolite membranes can be used as a model for the development of robust molecular sieve membranes with superior separation characteristics. We describe the characterization of natural clinoptilolite membranes made from dense mineral deposits by single gas H2 and CO2 permeation. Permeability values as a function of temperature and pressure were analyzed on the basis of mass transport fundamentals of gas permeation through zeolite and nonzeolite pathways. H2 and CO2 fluxes through the membranes were fitted with a model based on a combination of zeolitic, Knudsen, and viscous transports so that the selective and nonselective flux fractions could be quantified. An increase in feed pressure increased the total permeance especially at low temperatures. The membranes were also characterized by XRD, SEM, and EDX analysis.