Investigation of SO2 solubilities in some biobased solvents and their thermodynamic properties

Solubilities of SO2 have been determined in four biobased solvents (BBSs) at temperatures between 293.15 K and 323.15 K with 10 K intervals and pressure scope of (0-120.0) kPa using isochoric saturation method. The BBSs were selected from butyl lactate (BL), glyceryl triacetate (GT), triethyl citrate (TEC), and acetyl triethyl citrate (ATEC). Henry's constants and thermodynamic properties such as Gibbs free energy, enthalpy and entropy of dissolution were derived from the solubility data. The gravimetric solubilities of SO2 in BBSs were in the range of (0.07-8.52) mol.kg−1 and changed with the sequence of GT > BL > TEC ≈ ATEC. All the dissolution enthalpies were negative at each condition. The performances of SO2 absorption in these solvents were further compared with those in some ionic liquids as well as common absorbents. The results illustrated that present BBSs possessed the potentiality as SO2 absorbents due to their relatively large absorption ability, small absorption enthalpy, low toxicity, and biodegradability.