CO2-facilitated transport through poly(N-vinyl-γ-sodium aminobutyrate-co-sodium acrylate) polysulfone composite membranes

Poly(N-vinyl-gamma-sodium aminobutyrate-co-sodium acrylate) (VSA-SA)/polysulfone (PS) composite membranes were prepared for the separation of CO2. VSA-SA contained secondary amines and carboxylate ions that could act as carriers for CO2. At 20 degrees C and 1.06 atm of feed pressure, a VSA-SA/PS composite membrane displayed a pure CO2 permeation rate of 6.12 X 10(-6) cm(3)(STP)/cm(2) s cmHg and a CO2/CH4 ideal selectivity of 524.5. In experiments with a mixed gas of 50 vol % CO2 and 50 Vol % CH4, at 20 degrees C and 1.04 atm of feed pressure, the CO2 permeation rate was 9.2 X 10-6 cm(3) (STP) /cm(2) S cmHg, and the selectivity of CO2/CH4 was 46.8. Crosslinkages with metal ions were effective for increasing the selectivity. Both the selectivity of CO2 over CH4 and the CO2 permeation rate had a maximum against the carrier concentration. The high CO2 permeation rate originated from the facilitated transport mechanism, which was confirmed by Fourier transform infrared with attenuated total reflectance techniques. The performance of the membranes prepared in this work had good stability. (c) 2006 Wiley Periodicals, Inc.