CO2 separation from a mixture of CO2/C2H6 through membranes containing immobilized solutions of diethanolamine (DEA) and poly(ethylene glycol) (PEG) was carried out. The effects of flow pattern, flow rates, DEA concentration and CO2 partial pressure were investigated. The addition of DEA in the membrane matrix resulted in the enhancement of CO2 transport rate across the membrane. CO2/C2H6 separation factors of up to 145 were obtained. Higher selectivities were obtained at lower CO2 partial pressure differential conditions. An increasing CO2 partial pressure differential across the membrane resulted in the saturation of the DEA carrier.