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Abstract

The facilitated transport of CO2 through ion exchange membranes containing organic amine counterions was studied. Steady state CO2 fluxes were measured from pure gas streams and mixtures with CH4. Facilitation factors for CO2 up to 26.7 were calculated from transport data. Transport measurements were binary mixtures of CO2 and CH4 yielded ratios of CO2 flux to CH4 flux ranging from 29.0 to 264. Conversion of flux ratios to permeabilities yielded separation factors up to 551 for CO2 over CH4, 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 CO2 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.