Investigation of tertiary amine-based PILs for ideal efficient SO2 capture from CO2

Four tertiary amine-based protic ionic liquids (PILs) have been carefully designed to investigate the performance of SO2 uptake. Their physical properties of densities and viscosities were determined. In the four PILs, the highest capacity for SO2 of the four PILs reached up to 5.64 mol/kg ILs (P = 1.0 bar, T = 313.2 K). The ideal selectivity of SO2/CO2 was up to 250 in the separation application of SO2 from CO2. The kinetic study demonstrated that the PILs could efficiently capture SO2 quickly under the ambient pressure. Based on the SO2 absorption capacity and selectivity, excellent recyclability, and fast absorption process, the PILs in this work are considered as a potential alternative to traditional absorbents in the flue gas desulfurization (FGD).