THERMODYNAMIC MODELING OF CONCENTRATED MULTICOMPONENT AQUEOUS-ELECTROLYTE AND NONELECTROLYTE SOLUTIONS

A new approach is presented for calculation of activity coefficients i n multicomponent aqueous electrolyte and non-electrolyte solutions. Th e approach is based on an integration of the Gibbs-Duhem equation. It is shown that using standard thermodynamic properties for the pure com ponents and for the components at infinite dilution in water, it is po ssible to predict joint solubilities of both electrolytes and non-elec trolytes. To illustrate the usefulness of the method proposed in this work, calculations of solubility are presented for the two-electrolyte systems H2O-NaCl-KCl, H2O-NaNO3-KNO3, H2O-CaCl2-NaCl, and for a syste m containing both an electrolyte and a non-electrolyte H2O-sucrose-NaC l. The solubility of carbon dioxide at different pressures in water co ntaining various electrolytes [Ca(NO3)(2), NaCl, CaCl2,Na2SO4] is also calculated.