Modeling H2S and CO2 solubility in ionic liquids using the CPA equation of state through a new approach

In this communication, the solubility of two single gases, hydrogen sulfide and carbon dioxide, in the fourteen ionic liquids ([emim][eFAP], [emim][EtSO4], [emim][OTf], [emim][Tf2N], [bmim][BF4], [bmim][PF6], [hmim][PF6], [hmim][Tf2N], [omim][PF6], [omim][Tf2N], [HOemim][BF4], [HOemim][OTf], [HOemim][PF6] and [HOemim][Tf2N]) are modeled using the CPA EoS through a new approach. First, the critical temperature of ionic liquids was estimated using modified Lydersen-Joback-Reid method. Then, Using the CPA EoS, the pure parameters of ionic liquids were obtained through optimization on both of H2S and CO2 solubility data in ionic liquids as well as experimental liquid density data of ionic liquids. In next step, the interaction parameters between the ionic liquids and H2S as well as the ionic liquids and CO2 were calculated. Using the obtained pure parameters of the ionic liquids and the interaction parameters, the vapor-liquid equilibrium data were tested for thermodynamic consistency. Also, the proposed systems were modeled by the SRK EoS and the obtained results were compared by the obtained ones by the CPA EoS. For all the studied systems, the percent average absolute deviation (AAD %) was lower than 10% that shows good agreement between the experimental and calculated values.