Theoretical estimation of solvation parameters and interfacial tension of clusters of potassium halides in aqueous solutions

Abstract

Using the model of the formation of ionic clusters, an analytical equation valid for the equilibrium concentration of solute in the solution is derived. Employing Boltzmann statistics in conjunction with the experimental values of the equilibrium concentration of KF, KCl, KBr and KI electrolytes in aqueous solution at 25°C, the above analytical equation is used to compute the best values of the dielectric permittivity of the solvation shell for the K + ion and four anions separately. These values of the dielectric permittivity of the solvation shells are then used to compute adsorption energy of water molecules on the {100} surface of regular clusters and their surface tension in the solution as functions of type of the salt, its concentration and cluster size. It is found that both the average adsorption energy and the interfacial tension of regular clusters composed of i ions can be approximated by a linear function of i − 1 2 for different concentrations of all the investigated potassium halides, and that, depending on the concentration of the solutions, the surface tension of regular clusters in solutions can increase or decrease with their size.