A three-characteristic-parameter correlation model for strong electrolyte solutions

In this study, a characteristic-parameter correlation model was developed for the aqueous strong electrolyte solutions. This correlation model consisted of the long-range ion–ion interaction described by Pitzer–Debye–Huckel model and short-range ion-solvent molecule interaction attributed to solvation effect. The proposed approach is based on our previous paper of Lin et al. [C.-L. Lin, L.-S. Lee, H.-C.Tseng, Fluid Phase Equilibria, 90 (1993) 57–79.]. However, the significant improvement was made that the differential equation was solved analytically instead of numerically. This proposed model contains three parameters of physical significance and has been used to estimate the mean activity coefficients of electrolytes and osmotic coefficients of 144 aqueous strong electrolyte solutions from literature. Comparisons were made to the models of Chen et al. [C.C. Chen, H.I. Britt, J.F. Boston, L.B. Evans, AIChE, 28 (1982) 588–596; C.C. Chen, L.B. Evans, AIChE, 32 (1986) 444–454.], Ananth and Ramachandran [M.S. Ananth, S. Ramachandran, AIChE, 36 (1990) 370–386.], and Lin et al. [C.-L. Lin, L.-S. Lee, H.-C. Tseng, Fluid Phase Equilibria, 90 (1993) 57–79.]. The results also showed that the present model is at least as good as above models for 1-1 and 1-2 electrolyte solutions and improved very much for 2-1, 2-2, 3-1, and 3-2 electrolyte solutions.