Highly CO2-selective composite membranes from amino-functionalized imidazolium-based Poly(ionic liquids)

Design and synthesis of novel poly(ionic liquids) (PILs) containing amino groups hold great promise in CO2 separation fields owing to the tunability of the cation and anion, as well as the high CO2 affinity of the amino groups. Herein, two novel amino-functionalized PILs were designed for the preparation of composite membranes by casting the synthesized PIL-based solutions on the top of polysulfone ultrafiltration membranes to explore the effect of different chemical structures on the separation performances of the NH2-carrier-based membranes. Highly CO2-selective membranes with a CO2/N2 selectivity of 173.5 were obtained by introducing the mobile carrier of 2-(1-piperazinyl) ethylamine sarcosine (PZEA-Sar) into the amino-functionalized PIL-based membranes, which provides the synergistic effect from both fixed-site and mobile carriers for promoting CO2-facilitated transport. Thus, the developed membranes may offer a high energy-efficiency process for industrial CO2 capture.