Patent ID: 8747521

Claim:
A gas separation membrane to separate at least one acid gas from a mix gas, comprising in this order: a first layer that is porous; a second layer that is a separation-active layer containing a compound having a molecular weight of 150,000 or less and capable of interacting with the acid gas; and a third layer having high gas permeability, wherein the second layer comprises at least one hydrophilic cross-linked polymer and the hydrophilic cross-linked polymer comprises at least one repeating unit selected from polyethylene glycol, polypropylene glycol, polyvinyl alcohol, polyvinyl acetate, polyvinylpyrrolidone, polyethyleneimine and polyallylamine, the third layer comprises a cross-linked polymer and the cross-linked polymer comprises at least one repeating unit selected from polyethylene glycol, polypropylene glycol, polysiloxane, and polyolefin; and wherein the compound having a molecular weight of 150,000 or less and being capable of interacting with an acid gas is at least one acid gas carrier selected from hydroxide of alkali metal, alkoxide of alkali metal, alkali metal carbonate, alkali metal bicarbonate, alkali metal phosphate, hydroxide of alkaline earth metal, alkoxide of alkaline earth metal, alkaline earth metal carbonate, alkaline earth metal bicarbonate, alkali metal phosphate, organic amine, ion liquids and metal complexes.