Densities and apparent molar volumes for aqueous solutions of HNO₃−UO₂(NO₃)₂ at 298.15 K

Abstract

In order to obtain the exact information of atomic number density in the ternary system of HNO₃−UO₂(NO₃)₂−H₂O, the densities were measured with an Anton-Paar DMA60/602 digital density meter thermostated at 298.15±0.01 K. The apparent molal volumes for the systems were calculated from the experimental data. The present measured apparent molar volumes have been fitted to the Pitzer ion-interaction model, which provides an adequate representation of the experimental data for mixed aqueous electrolyte solutions up to 6.2 mol/kg ionic strength. This fit yields θ^V, and ψ^V, which are the first derivatives with respect to pressure of the mixing interaction parameters for the excess free energy. With the mixing parameters θ^V, and ψ^V, the densities and apparent molar volumes of the ternary system studied in this work can be calculated with good accuracy, as shown by the standard deviations.