A preferential CO2 separation using binary phases membrane consisting of Pebax®1657 and [Omim][PF6] ionic liquid

Pebax (R) 1657 and [Omim][PF6] ionic liquid (IL) were used to fabricate a blend membrane and applied for CO2 separation. The changes upon adding ionic liquid into the polymer matrix as well as the membrane characteristics were studied through SEM, FTIR, DSC and TGA analysis. The obtained gas permeation results indicated that the CO2 permeability in all membranes was much higher than the other studied gases. CO2 permeability of Pebax containing 8 wt% IL increased from 82.3 Barrer up to 125.6 Barrer at a pressure of 2 bar, which showed a 53% increment compared to the neat Pebax membrane. Furthermore, as the [Omim][PF6] loading within the polymer matrix was increased, the CO2/CH4 and CO2/N-2 selectivities improved. In addition, the permeability and selectivity of gases was enhanced as the feed pressure increased. Upon increasing feed pressure to 10 bar, the CO2 permeability of Pebax containing 8 wt% IL reached 185.3 Barrer, which was approximately 48% higher than the permeability at a pressure of 2 bar. Moreover, the selectivity of CO2/CH4 and CO2/N-2 for the Pebax/8 wt% IL membrane at pressure of 2 bar was 15.3 and 46.5, respectively, which improved to 19.7 and 59.8 as the pressure increased to 10 bar.