Patent ID: 7011694

Claim:
A process for purification of H 2 from a synthesis gas containing CO 2 by the water-gas-shift reaction, comprising: contacting a CO 2 -containing synthesis gas stream with a first side of a CO 2 -selective membrane comprising a polyimide hard segment and a polyamine, wherein the membrane further comprises at least one salt of an amino acid selected from salts having the formulae: wherein R 1 , R 2 and R 3 are hydrogen or alkyl groups having from 1 to 4 carbon atoms, n is an integer ranging from 0 to 4, A m+ is a cation having a valence of 1 to 3 and selected from metals of Groups IA, IIA, and IIIA of the Periodic Table of Elements and an amine cation having the formula: wherein R 4 and R 5 are hydrogen or alkyl groups having from 1 to 4 carbon atoms, R 6 is hydrogen, an alkyl group of from 1 to 4 carbon atoms or an alkyl amine of from 2 to 6 carbon atoms and 1 to 4 nitrogen atoms, y is an integer ranging from 1 to 4, and m is an integer equal to the valence of the cation; and withdrawing a CO 2 -enriched permeate from an obverse side of said CO 2 -selective membrane.