Facilitated transport of CO2 through polyvinylamine/polyethlene glycol blend membranes

Poly(vinylamine)/poly(ethylene glycol) blend membranes were prepared. The effects of blend polymer composition on the membrane structure and CO2/CH4 separation performance were investigated. The results show that membrane crystallinity are at a minimum against poly(ethylene glycol)(PEG) content, while the permeation rates of CO2 and CH4 are the maximum. The blend membrane with 10 wt% PEG has the highest pure CO2 permeation rate of 5.8×10−6 cm3 (STP)/cm2.s.cm Hg and the highest selectivity of 63.1 at 25°C and 96 cm Hg of feed pressure. The effects of cross-linking and the coupling effects between CO2 and CH4 were also investigated. The selectivity increased remarkably when the membrane is cross-linked. For mixed gas of constant CH4 partial pressure and changing CO2 partial pressure, the CH4 permeation rate increased with an increase of CO2 partial pressure due to the coupling effects.