Highly selective capture of sulfur dioxide by low viscosity 1,2,4-triazole + [Emim]Cl deep eutectic solvents

Abstract

Sulfur dioxide (SO2) is a toxic gas emitted from industrial waste gases, and its removal is crucial to improve the quality of the atmosphere and reduce the harm to human health. In this work, we investigated the absorption of SO2 by deep eutectic solvents (DESs) with low viscosity 1,2,4-triazole (Trtz) and 1-ethyl-3-methylimidazole chloride ([Emim]Cl) under different conditions. We briefly investigated the mechanism of sulfur dioxide absorption by DESs and measured the absorption performance of Trtz + [Emim]Cl DESs for SO2 at different molar ratios. The experimental results show that all Trtz + [Emim]Cl DESs have good capture performance for SO2, among which 298.2 K Trtz + [Emim]Cl (1:3) DES has an absorption capacity of 18.15 mol/kg (102.2 kPa) for SO2, surpassing most previously reported deep eutectic solvents. We found that the solubility of CO2 and N2 is much lower than that of SO2. The absorption capacity of DESs for SO2 is about 452 times that of CO2 and 1530 times that of N2.Therefore, this absorbent has extensive application prospects in the field of SO2 gas capture.