Advances in applications of ionic liquids for phase change CO2 capture

Abstract

Research and development of novel absorbents with high efficiency and low energy consumption is the key to achieve large-scale carbon dioxide (CO2) emissions reduction by chemical absorption method. Due to the advantages of adjustable structure, negligible vapor pressure, low specific heat capacity, and moderate reaction heat, the CO2 capture technology based on ionic liquids (ILs) absorbents has remarkable potential for energy conservation. The applications of ILs in CO2 capture process with phase change can further cut down the regeneration energy penalty. In this article, we reviewed the recent progress in ILs-based phase change absorbents for CO2 capture technology, focusing on phase change behaviors, reaction and phase change mechanisms, and process flow and energy consumption analyses. Applications of ILs as solvents or absorbents in phase change absorbents were discussed including liquid–liquid biphasic absorbents, liquid–solid biphasic absorbents, and phase change ILs. We have provided challenges and outlooks on novel ILs-based phase change absorbents for CO2 capture from laboratory research to industrial applications.