Prediction of the solid-liquid equilibrium of ternary and quaternary salt-water systems. Influence of the e-NRTL interaction parameters

The aim of this work is to use the refined binary electrolyte-solvent interaction parameters of the e-NRTL model obtained in a previous paper (J.L. Valverde et al. Fluid Phase Equilibria (2022), 551, 113264) and to analyse the impact of considering the electrolyte-electrolyte interaction parameters different from zero on the prediction of solid-liquid equilibria in salt-water mixtures. For this purpose, experimental data were fitted to the complete e-NRTL model by non-linear regression. Ternary (two salts + water) and quaternary (three salts + water) systems were considered. Almost all the systems analyzed were precisely predicted by using the e-NRTL model with the electrolyte-water pairs regressed previously and electrolyte-electrolyte ones set to zero. Including the electrolyte -electrolyte binary parameters in a proper way can slightly improve the solid-liquid equilibria prediction for some of the selected systems. The Na2SO4+K2SO4+Li2SO4+H2O mixture was described poorly than the remainder ones computed due to the complexity of the system which exhibits the formation of multiple salts.