An analytic model for aqueous electrolyte solutions based on fluctuation solution theory

Abstract

A model for strong aqueous electrolyte solutions based on fluctuation solution theory is introduced. The key thermodynamic quantities in the model—direct correlation function integrals—are evaluated using results from the mean spherical approximation for mixtures of charged hard spheres for the electrostatic part, from hard sphere mixture theory for the excluded volume part and from corrections for infinite dilution properties obtained from experimental data. This model is compared to experimental data on aqueous NaCl and NaBr solutions at room temperature from infinite dilution to 25% salt by weight at pressures of 1 and 250 bar with very encouraging results.