ION-INTERACTION APPROACH FOR VOLUMETRIC CALCULATIONS FOR SOLUTIONS OFSINGLE ELECTROLYTES AT 25-DEGREES-C

The ion interaction approach of Pitzer permits the prediction of therm odynamic characteristics of multiple-electrolyte solutions if the ion interaction parameters (Pitzer parameters) for each type of single-ele ctrolyte solutions are known. The purpose of the present paper is to s uggest the best sets of volumetric Pitzer parameters, V(MX)oBAR, beta( MX)(O)V, beta(MX)(1)V, beta(MX)(2)V and C(MX)V, at 25-degrees-C for sa lts formed from Na+, K, Mg2+, Ca2+, Cl-, Br-, HCO3-, CO32- and SO42- i ons. Using essentially all published relevant experimental data, a dat abase for the mass densities and apparent molar volumes at 25-degrees- C vs. the solute concentration has been created for each single-electr olyte solution type. Unreliable data were discarded by an appropriate statistical lest. The remaining data, covering solute concentrations f rom infinite dilution to saturation, were used to compute the unrestri cted and restricted sets of volumetric Pitzer parameters by least squa res. Taking the differences between the calculated and experimental de nsities and apparent molar volumes as the criterion of quality , the b est set of volumetric Pitzer parameters was selected for each type of electrolyte and was used to calculate the mass densities, at 25-degree s-C, of some multiple-electrolyte solutions resembling Dead Sea waters .