Dilution enthalpies, osmotic and activity coefficients of aqueous electrolyte binary systems at different temperatures using an extended solvation theory

We present a correlation that accurately captures both solute–solvent and solute–solute interactions. This model is particularly effective in representing concentrated electrolytes, such as those encountered in batteries and industrial brines, thereby offering significant utility for advanced industrial applications. In this work, we have used two models based upon an extended solvation theory to correlate the temperature dependence of activity coefficients, osmotic coefficients, and dilution enthalpies for binary aqueous electrolyte systems. In the first model, the Debye Hückel equation is used with the solvation model (DH-MS model); in the second, the Pitzer-Debye-Hückel equation is used with the same solvation model (PDH-MS model). We have compared the correlating performance of these two models with the Archer extended Pitzer model. Forty-seven aqueous solutions with electrolytes 1:1, 1:2, 2:1 and 2:2 have been used to test these models. When correlating the activity and osmotic coefficients, the average percentage deviation from the Archer model is slightly higher than from the solvation models. In the case of dilution enthalpies, the DH-MS model is better in 63.64 % of the systems, followed by the PDH-MS model with 36.36%. In the case of dilution enthalpies, the Archer model does not outperform the solvation models in any of the systems studied.