Mean Activity Coefficients of NaCL in the NaCL + SrCl2 + H2O Ternary System at 278.15 K by the Cell Potential Method

In this article, research on the thermodynamic mean activity coefficients for the ternary system (NaCl-SrC12-H20) has been carried out. A cell without a liquid junction can be expressed as sodium-ISElsodium chloride (mA), strontium chloride (m8)I chlorine-ISE. It is used to determine the activity coefficients in these mixtures at 278.15 K by the cell potential method. Then, the total ionic strengths are I = 0.0100-3.0000 mol-kg-1 with different yb (ionic strength fraction) = (0.0, 0.2, 0.4, 0.6, and 0.8). The relationship diagrams between y,,,a (mean activity coefficients of NaCI) and yb (ionic strength fraction) were plotted. Mixed interaction parameters ONa,sr and 111Na,Sr,CI of this system in Pitzer equations at 278.15 K were fitted by using the determined activity coefficients and multiple regression method. In addition, those obtained parameters were also used to calculate v SrC12 (mean activity coefficients of SrC12) by the Pitzer equations. Accordingly, the osmotic coefficients, water activity, and excess Gibbs free energy in the mixtures were studied in detail.