Electrolyte-UNIQUAC-NRF model based on ion specific parameters for correlation of mean activity coefficient of electrolyte solutions

The Electrolyte-UNIQUAC-NRF excess Gibbs function, including a long range term expressed by the equation of Pitzer-Debye- Hückel, and a short range term based on the Electrolyte-UNIQUAC-NRF model, is applied for calculation of activity coefficient of aqueous electrolyte solutions using ion specific parameter. In this approach, the ion specific interaction energy parameters of each species with the other species are calculated by global optimization of experimental activity coefficients for 35 electrolyte systems. Subsequently the total number of 16 ion specific parameters is obtained for water and several cations and anions. Furthermore, the estimated individual ion parameters have been reasonably used to predict osmotic coefficient of electrolyte solutions. Finally, by comparing the obtained deviations for each single-salt solution, it could be demonstrated that the activity and osmotic coefficient of several electrolyte solutions with common cation or anion would be calculated by limited adjustable parameters of ions.

Keywords:

Electrolyte-UNIQUAC-NRF , activity coefficient , osmotic coefficient , Electrolyte solution