Study on absorption, desorption and mechanism of low concentration of SO 2 in the dimethyl sulphoxide +2-propoxyethanol binary system

Based on the efficient and reversible absorption of low-concentration of SO2, this work was designed to select a binary system of 2-propoxyethanol (2-PE) + dimethyl Sulphoxide (DMSO) with different concentration ratios as the absorption liquid. The gas–liquid equilibrium (GLE) data of SO2 absorbed by these absorbing liquids were measured at p = 123.15 kPa, T = 298.15–318.15 K. By fitting the gas–liquid equilibrium data, it is found that it conforms to Henry’s law, and further the molar Gibbs free energy change (△solGm molar dissolution entropy (△solSm)_ and molar dissolution enthalpy (△solHm) of the absorption process were obtained. Through FT-IR and UV spectroscopic techniques combined with Gaussian and Multiwfn calculation software, it is analysed that there is a hydrogen bond between the H atom on the hydroxyl group of 2-PE and the O atom of SO2.