Absorption, desorption and spectroscopic investigation of sulfur dioxide in the binary system ethylene glycol + dimethyl sulfoxide

Isothermal gas–liquid equilibrium (GLE) data were measured at 298.15 K and 122.66 kPa for dilute SO2 in the binary system ethylene glycol (EG) + dimethyl sulfoxide (DMSO), in which SO2 partial pressures were calculated in range of (0–130) Pa. The solubility of dilute SO2 in the binary system gradually increased with the increasing DMSO concentration in the whole composition. Based on the GLE data, Henry’s law constants (HLC) of dilute SO2 in the binary system EG (1) + DMSO (2) were obtained. The regeneration experiments showed that the 97.6% SO2 could be separated from the dissolving SO2 solution at 80 °C and bubbling N2 within 30 min; meanwhile, SO2 desorption ran smoothly and solubility of SO2 no significant dropped after five-successive absorption–desorption cycles. Furthermore, to obtain important reaction mechanism, the intermolecular interaction among SO2, EG, and DMSO were investigated by UV–vis, FTIR, and 1H NMR spectroscopic techniques. Spectral results showed that the interaction among EG, DMSO, and SO2 were resulted from both the O → S charge-transfer interaction and intermolecular hydrogen bonding.