PERMEATION OF BINARY GAS-MIXTURE THROUGH GLASSY POLYMER MEMBRANES WITH CONCENTRATION-DEPENDENT DIFFUSIVITIES

An analytical solution has been obtained for the modified dual-mode mobility for a single gas proposed by Zhou and Stern and extended to a binary gas mixture to describe the pressure dependence of mean permeability coefficients for CO2 and CH4 mixtures in homogeneous cellulose triacetate membranes. The permeabilities calculated from the model fitted the corresponding experimental results quite well. Permeation experiments for equimolar CO2 and CH4 mixture in a homogeneous membranes of methyl methacrylate and n-butyl acrylate copolymer were performed along with sorption experiments for pure CO2 and CH4 to test the applicability of the model. The experimental permeabilities were close to those calculated from the model.