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

[Display omitted] • Two novel amino-functionalized PILs were designed by incorporating the amino groups into PILs. • The copolymerized PILs were prepared as composite membranes to explore the effect of different chemical structures on their separation performance. • Highly CO 2 -selective membranes with a superior CO 2 /N 2 selectivity of 173.5 were obtained. • Membranes with both fixed-site and mobile carriers provide the synergistic effect for CO 2 -facilitated transport. Design and synthesis of novel poly(ionic liquids) (PILs) containing amino groups hold great promise in CO 2 separation fields owing to the tunability of the cation and anion, as well as the high CO 2 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 NH 2 -carrier-based membranes. Highly CO 2 -selective membranes with a CO 2 /N 2 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 CO 2 -facilitated transport. Thus, the developed membranes may offer a high energy-efficiency process for industrial CO 2 capture. [ABSTRACT FROM AUTHOR]