Improving CO2/N2 separation performance using nonionic surfactant Tween containing polymeric gel membranes

Abstract

Polymeric gel membranes containing 0 to 65 wt% of Tween20, Tween21 and Tween80 in PEBA2533 were prepared using a solvent casting method. The effect of Tween with different lengths of alkyl chain on the properties and performance of the gel membranes was discussed. The results showed a better compatibility of PEBA2533 with Tween21 than Tween20 and Tween80. Both the pure CO₂ permeability and CO₂/N₂ selectivity increased with the increase in the number of N-alkyl groups in Tween. On the other hand, with the increase of Tween content, CO₂ permeability and CO₂/N₂ selectivity simultaneously increased. The best separation performance was achieved for the PEBA2533/Tween80-65 gel membrane, which had CO₂ permeability of 289 Barrer and CO₂/N₂ selectivity of 40.70, at 0.6 atm and 25 °C. This suggests a potential application in gas separation membranes, for instance for CO₂ capture.