Application of modified PHSC model in prediction of phase behavior of single and mixed electrolyte solutions

The modified perturbed hard sphere chain (e-PHSC) equation of state (EoS) has been used for correlation and prediction of thermo-physical properties of single and mixed aqueous electrolyte solutions. In order to take electrostatic contribution into account, the primitive mean spherical approximation (MSA) term has been utilized. The proposed electrolyte equation of state (e-EOS) has two ion-based parameters per each ion. Ion specific parameters were obtained by simultaneous adjustment using mean ionic activity coefficient (MIAC) and solution liquid density experimental data of single electrolyte solutions. In order to check the accuracy of the model, water activity, osmotic coefficient and vapor pressure of single electrolyte solutions have been calculated using adjusted parameters. Finally water activities, MIACs, solution liquid densities, osmotic coefficients and vapor pressures of various mixed electrolyte solutions were predicted. The results showed that using e-PHSC model, MIACs, osmotic coefficient, water activity and vapor pressure and liquid density of mixed electrolyte solutions up to 6.5, 10, 10, 10 and 5 of ionic strength can be well predicted without any additional adjustable parameters.

► PHSC model has been extended to electrolyte solutions.
► The model parameters were obtained using thermodynamic properties of single electrolyte solutions.
► An ion-specific model has been developed for prediction of thermodynamic properties of mixed electrolyte solution.