Abstract
In the present work, an equation-of-state-based approach has been used to correlate the experimental gas solubility data of carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), ammonia (NH3), nitrogen dioxide (NO2), sulfur dioxide (SO2) and hydrogen sulfide (H2S) in some representative deep eutectic solvents (DESs) having a common halide salt (choline chloride). Accordingly, two cubic equations of state (CEoS): Peng-Robinson and Soave-Redlich-Kwong coupled with van der Waals mixing rules, were considered here. As a matter of fact, in addition to the Soave alpha function, the one proposed by Yokozeki was also tested in an attempt to obtain improved solubility estimations at low gas concentrations. The best possible representation of experimental solubility data was achieved by adjusting the value of two binary interaction parameters present in the mixing rules (assuming that the DES is a pseudo-pure component), namely, ?? ??,?? (enthalpic differences due to hydrogen-bonding effects) and ?? ??,?? (entropic differences due to diverse molecular structures of the constituents) using a least-square procedure for each CEoS. Furthermore, it was found that the Yokozeki alpha function in the CEoS correlates the phase equilibria of some of the Gas-DES systems slightly better than the Soave alpha function. Overall speaking, the performance of the present modelling approach was quite good in representing the experimental solubility of the aforementioned acid and sour gases in several choline chloride-based DESs within their corresponding experimental uncertainties in the majority of the cases.
