Swelling behavior and gas permeation performance of PVAm/PVA blend FSC membrane

Water swelling behavior and permeation performance of CO2 and N2, CH4, H2 in polyvinylamine/polyvinylalcohol (PVAm/PVA) blend fixed-site-carrier (FSC) membrane were studied with respect to the relative humidity of the gases in the separation system. Two exponential fittings were presented to describe the two stage swelling behavior of the membrane. The effects of operating parameters on CO2 separation performance were investigated and optimized. Interactions between gases in mixed gas separation were discussed. Experiments showed exponential dependencies of gas permeance on relative humidity, which could be explained by the dependence of gas diffusion on membrane swelling and the unique CO2 facilitated transport membrane in this membrane. The reversible hydration reactions of CO2 initiated by amino carriers in the water swelling membrane facilitate the CO2 transport. CO2 diffuses in the form of HCO3− in this membrane, resulting in both high CO2 permeance and selectivity over other gases. A selectivity up to 45 and CO2 permeance up to 0.55 m3(STP)/(m2 h bar) for CO2–CH4 separation, and a selectivity up to 160 and CO2 permeance up to 0.83 m3(STP)/(m2 h bar) for CO2–N2 separation were documented.