Thermodynamic Modeling of Aqueous Ionic Liquid Solutions Using PC-SAFT Equation of State

In this work, an equation of state has been utilized for thermodynamic modeling of aqueous ionic liquid (IL) solutions. The proposed equation of state is a combination of perturbed chain statistical associating fluid theory (PC-SAFT) equation of state and mean spherical approximation (MSA) term. In this model, the ion-based approach has been used to adjust the model parameters. The ion parameters have been estimated through simultaneous fitting to experimental mean ionic activity coefficient and liquid density data of strong electrolytes. Using adjusted ion parameters, osmotic coefficients, mean ionic activity coefficients, liquid densities, apparent molar volume, and water activity of several ILs, assumed as chainlike electrolytes, have been calculated. Results show that PC-SAFT, in combination with the MSA term has acceptable accuracy for prediction of density, apparent molar volume, and activity coefficient of ILs. The average deviations of predicted mean ionic activity coefficients, liquid densities, water activity, and apparent molar volume are 6.43, 0.86, 0.033, and 8.20%, respectively.