Volumetric Ion Interaction Parameters for Single-Solute Aqueous Electrolyte Solutions at Various Temperatures

Abstract

The ion interaction approach developed by Pitzer allows the prediction of thermodynamic characteristics of mixed electrolyte solutions at various temperatures, if the respective parameters for each type of single electrolyte solution are known. Among such thermodynamic characteristics are the volumetric ones (density and apparent molal volumes). A database for the densities and the apparent molal volumes versus concentrations was developed at a temperature interval of 288.15–368.15 K using all available literature sources for each single electrolyte solution formed by various electrically neutral combinations of the following ions (Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+, Cl−, Br−, HCO3−, CO32−, and SO42−). These are the most important ions for industrial solutions as well as for natural waters. Statistical treatment was applied to this database in order to discard poor data. The proper treatment of all sound quality apparent molal volumes, in a wide range of concentrations from infinite dilution through saturation, allowed us to compute sets of volumetric ion interaction parameters (V̄MX0, βMX(0)V, βMX(1)V, βMX(2)V, and CMXV) at various temperatures in a 288.15–368.15 K temperature interval. The validity of the selected sets at various temperatures was demonstrated by a comparison of the experimental and calculated densities for multiple-solute electrolyte solutions containing NaCl, KCl, MgCl2, and CaCl2 with an ionic strength reaching 9.23 that resembled Dead Sea water.