Novel pyrrolidinium-based polymeric ionic liquids with cyano counter-anions: High performance membrane materials for post-combustion CO2 separation

Abstract

Polymeric ionic liquids (PlLs) are blossoming as a nevv generation of materials aL the interface of many areas leading to a renaissance of the field of ionic polymers. Although PlLs are interesting membranes materials for CO2 separation, additional research is still required to realize their full potential. In this work, pyrroliclinium-based polymers containing different cyano-functionalized counter -anions were synthesized by straightforvvarcl anion exchange reactions and characterized. Their film forming ability blended with different amounts of free ionic liquid (IL) was evaluated and the CO2 and N-2 permeation properties through the prepared composites were determined. The results show that increasing the IL content in the composites not only increased CO2 permeability but also boosted the CO2/N-2 permselectivity, leading to improved separation performances. The best performance was achieved for the C(CN)(3)-based membrane containing 60 wt% of IL, which overcomes the Robeson 2008 upper bound, with CO2 permeability of 439.3 Bat rer and CO2/N-2 permselectivity of 64.4. Therefore, the pyrrolidinium-based PIL combined with the [C(CN)(3)](-) as counter-anion has potential for efficient post-combustion CO2 separation, suggesting the preparation of high performance membranes for industrial applications. (C) 2015 Elsevier B.V. All rights reserved.