Sulfur dioxide capture by deep eutectic solvents: Proposing purely predictive absorption models

Sulfur dioxide (SO₂) is one of the hazardous gases during coal or hydrogen sulfide combustion in petrochemical and coal-related industries. Unfortunately, SO₂ is released into the atmosphere in most SO₂-involved industries. The high concentration of SO₂ in the atmosphere leads to acid rain, which leads to various damage and destruction of the environment. Therefore, preventing SO₂ emissions into the atmosphere is vital. Considering environmental guidelines, Deep Eutectic Solvents (DESs), as the recent category of green solvents because of their eco-friendly characteristics are interesting. Considering the huge number of introduced DESs and also the costly and time-consuming process for experimental measurement of SO₂ absorption by DESs, it is vital to have predictive thermodynamic models for predicting SO₂ solubilities in DESs. In this study, for the first time in open literature, two general, accurate, and predictive models of atomic and group contributions were developed for SO₂ absorption by various nature DESs based on a comprehensive data bank over wide ranges of temperatures and pressures. The gathered data bank includes 997 SO₂ absorption data points for 65 various nature DESs. Both developed GC and AC models showed reliable and predictive performances by presenting the AARD% values of 10.3 and 11.7, respectively.