CO2 capture and surface structures of ionic liquid-propanol solutions

Abstract

In-situ observations of normal CO2 (nCO2) absorption and desorption were carried out on hydrophobic quaternary ammonium ionic liquids (ILs). Time-resolved mass transfer was directly monitored under a nCO2 flow. Under the nCO2 atmosphere, the rhythmic mass fluctuation of nCO2 was observed in pure N-trimethyl-N-butylammonium bis(trifluoromethylsulfonyl)imide, [N4111][TFSI], in which nCO2 capture was found to be enhanced by the use of a 2-propanol. Surface structures of IL-propanol solutions were examined via X-ray and neutron reflectivity measurements. The complicated surface structures of the [N4111][TFSI]-propanol system were clarified in both air and nCO2via the complementary use of X-ray and neutron measurements, whereby the nCO2 capture in the ILs was found to be influenced by the surface structures.