Facilitated transport of CO₂ in ion exchange membranes

Abstract

Abstract The facilitated transport of CO 2 through ion exchange membranes containing organic amine counterions was studied. Steady state CO 2 fluxes were measured from pure gas streams and mixtures with CH 4 . Facilitation factors for CO 2 up to 26.7 were calculated from transport data. Transport measurements were binary mixtures of CO 2 and CH 4 yielded ratios of CO 2 flux to CH 4 flux ranging from 29.0 to 264. Conversion of flux ratios to permeabilities yielded separation factors up to 551 for CO 2 over CH 4 , which are compared to literature data for polymeric membranes. The transport data support a mobile, reactive‐carrier facilitated transport mechanism with a carbamate zwitterion complex. Effective diffusivities for CO 2 and the carrier‐gas complex were determined from transport data. A reaction equilibrium model predicted facilitation factors that were in very good agreement with experimental values. Potential applications are also discussed.