High Absorption Performance of HCl in 1-Octyl-3-Methylimidazolium Chloride

Incineration of wastes and combustion of chlorine-rich coal are the major sources of local and global environmental pollution related to hydrogen chloride (HCl) emission. At the same time, HCl is a common tail gas in chemical industry such as PVC and Freon production. HCl is regarded as the most significant substance to destroy the ozone layer, moreover it is harmful, corrosive and can contribute to the production of chlorinated unburned hydrocarbons and dioxins. In order to capture HCl for reducing the environmental risk and utilizing HCl as chloride resource, the investigation of efficient methods for HCl removal and recovery is critically important in recent decades. Although there are some commercial processes for flue gas dechlorination, such as hydrated lime, ion-exchange resin, condensation, alkali absorption, water absorption etc., the disadvantages of these processes are obvious, such as low efficiency, absorbent waste, secondary pollution and so on. Therefore, a novel solvent that could facilitate the separation of HCl from flue gas without concurrent loss of the absorbent into the gas stream is highly required. In this regard, ionic liquids (ILs) show great potential as an alternative for such applications. In recent years, significant progress has been made in the application of ILs as alternative solvents due to their unique properties such as negligible vapor pressure, a broad range of liquid temperatures, excellent thermal and chemical stabilities, tunable physicochemical characteristics and selective absorption of certain organic and inorganic materials, such as CO2, SO2 , NH3 and so on.