Carbon Dioxide Capture by Aqueous Ionic Liquid Solutions.

Confined water in aqueous solutions of imidazolium-based ionic liquids (ILs) associated with acetate and imidazolate anions react reversibly with CO2 to yield bicarbonate. Three types of CO2 sorption in these "IL aqueous solutions" were observed: physical, CO2 -imidazolium adduct generation, and bicarbonate formation (up to 1.9 molbicarbonate  mol-1 of IL), resulting in a 10:1 (molar ratio) total absorption of CO2 relative to imidazolate anions in the presence of water 1:1000 (IL/water). These sorption values are higher than the classical alkanol amines or even alkaline aqueous solutions under similar experimental conditions.