Solubility of dilute sulfur dioxide in binary mixtures of ethylene glycol and tetraethylene glycol dimethyl ether

Solubility data of dilute SO2 in binary mixtures of ethylene glycol (EG) and tetraethylene glycol dimethyl ether (TEGDME) were measured by the isothermal gas-liquid equilibrium experiments at temperatures ranging from 293.15 K to 313.15 K with SO2 partial pressure below 120 Pa. The results show that the solubility of SO2 increases with the increasing mass fraction of TEGDME in the mixtures. When the mass fraction of TEGDME is up to 80.00%, the mixture exhibits the greatest solubility. Henry's law constants (H′), enthalpy changes (ΔH), entropy changes (ΔS) and Gibbs free energies (ΔG) of the absorption processes were also calculated. According to the obtained thermodynamic parameters, the absorption processes are physical absorptions, which obey Henry's law within the investigated SO2 partial pressure region. Furthermore, the addition of TEGDME shows significant improvement over pure EG in absorption solubility, and the mixtures after SO2 absorption can be regenerated by heating and N2 bubbling. The binary mixtures have a potential application in SO2 removal.