Novel ionic liquids phase change solvents for CO2 capture

Abstract

Phase change solvents have a great potential to reduce the energy consumption in the CO2 capture process. In this work, a class of novel phase change solvents composed of ionic liquids with some solvents are developed and the performances for capturing CO2 are investigated. Such a class of phase change solvents present very competitive CO2 capture capability, e.g., the CO2 capacity by [TETA]Br-PMDETA-water system is high to 2.631 mol CO2/L under the conditions of 303 K, 4 M, [TETA]Br and PMDETA mole ratio 3:7, while avoid the solvent loss, a major problem in traditional phase change solvents, because ionic liquids are not volatile. Further, the phase change solvents can be regenerated at 423 K and the regeneration efficiency remains above 95% after four cycles. The absorption and phase transition mechanism are revealed with 13C NMR, and such a high capture capability is ascribed to the mutual promoting effect of [TETA]Br and PMDETA.