Solubility of carbon dioxide in encapsulated ionic liquids

Ionic liquids (ILs) have been object of extensive research during the last years due to their potential for industrial application with special interest on carbon dioxide (CO2) capture. Nonetheless, ILs transport properties have stand out as the major drawback for their use on absorption applications. This work proposes ionic liquids encapsulated (ENILs) into carbonaceous submicrocapsules, as a novel material for CO2 capture. This innovative material takes advantage of the ILs gas-absorbing properties and cost-effectiveness while circumventing the IL viscosity by increasing the surface contact area with respect to the bulk fluid. The ENILs prepared using 1-ethyl3-methylimadazolium bis(trifluoromethylsulfonyl)imide ([C2C1im][NTf2]) and N-methyl-2hydroxyethylammonium pentanoate (m-HEAP), were characterized by SEM, TEM, elemental analysis, TGA and BET to assess their morphology, chemical composition, porous structure and thermal stability. The absorption of CO2 on these materials was studied up to 0.6 MPa and 353 K. Desorption of CO2 from the exhausted ENILs was evaluated, at mild conditions, evidencing the ENILs as suitable separating agents for CO2 capture, with high sorption capacity and fast and complete regeneration, and feasible alternatives to bulk IL absorption.