Supported Imidazolium-Based Ionic Liquids on a Polysulfone Matrix for Enhanced CO(2) Capture

The present work demonstrates the potential for improved CO(2) capture capabilities of ionic liquids (ILs) by supporting them on a polysulfone polymeric matrix. CO(2) is one of the main gases responsible for the greenhouse effect and is a focus of The European Commission, which committed to diminishing its emission to 55% by 2023. Various ILs based on combinations of 1-butyl-3-methyl- imidazolium cations and different anions (BMI·X) were synthesized and supported on a polysulfone porous membrane. The influence of the membrane structure and the nature of ILs on the CO(2) capture abilities were investigated. It was found that the membrane’s internal morphology and its surface characteristics influence its ILs sorption capacity and CO(2) solubility. In most of the studied configurations, supporting ILs on porous structures increased their contact surface and gas adsorption compared to the bulk ILs. The phenomenon was strongly pronounced in the case of ILs of high viscosity, where supporting them on porous structures resulted in a CO(2) solubility value increase of 10×. Finally, the highest CO(2) solubility value (0.24 mol(CO2)/mol(IL)) was obtained with membranes bearing supported ILs containing dicarboxylate anion (BMI.MAL).