Absorption and Separation of SO2 by Ionic Liquids

Room-temperature ionic liquids (ILs), which have excellent properties, such as extremely low vapor pressure, high thermal and chemical stability and tunable structures, are regarded as environmentally benign solvents. Due to their tunable structures and properties, ILs can be designed to endow with a high solvent power for SO2 absorption and separation, and they have been widely investigated in SO2 absorption and separation by many researchers. The paper briefly introduces the characters of ILs used for SO2 capture and separation from flue gas or mixed gas, the capacity of SO2 absorption in these ILs, the ways to enhance the absorption of SO2, and the mechanism of the absorption. Furthermore, the application prospect of the absorption by ILs is presented, and the existing problems and the further studies are discussed.