Absorption of SO₂ at High Temperatures by Ionic Liquids and the Absorption Mechanism

摘要

The capture of SO2 at or close to the temperatures of real flue gas is much more attractive in application. In this work, two kinds of ionic liquids (ILs) based on lactate anion were used to absorb SO2 at high temperatures from 100 to 120 oC. The ILs show high absorption capacities of over one mol SO2 per mol IL at 110 oC. The absorption of SO2 by the ILs based on lactate anion is reversible and the ILs can be reused for the capture of SO2 at high temperatures with high absorption capacity and thermal stability. Furthermore, the absorption mechanism of SO2 by the ILs was studied by FT-IR, 1H NMR and 13C NMR spectra. It has been found that there are strong chemical interactions between the ILs and SO2. Also the absorption mechanism is different when there is water present in ILs compared to when there is not.