Thermodynamic properties and solubilityof potassium fluoride in aqueous solutions at various temperatures

Abstract

The experimental and calculated solubilities of potassium fluoride in aqueous solutions were investigated at various temperatures. The experimental solubility of KF in aqueous solutions was determined up to mmax = 17.50 to 25.80 mol kg−1 respectively from 298.15 to 353.15 K. The calculated solubility requires the thermodynamic properties of the binary system based on the water activity measurements. Accordingly, the water activity of KF aqueous solutions were measured from diluted to the saturated solutions, using the hygrometric method at different temperatures. The related thermodynamic properties of KF(aq) were evaluated by the development of ion interaction model. The new binary parameters (β(0)(K,F), β(1)(K,F), and Cφ(KF)) were determined at various temperatures and used to evaluate the solute activity and the osmotic coefficients ranging from 298.15 to 353.15 K. The solubility product of KF(s) (given in lnKsp°) and the standard molar Gibbs energies of dissolution ΔGdiss° were also given at different temperatures.