Thermodynamics of extraction equilibria. Part 6. A further study of the method for determination of equilibrium constants of extraction processes

Abstract

The equilibrium constant (K) expression of the extraction of an inorganic compound (M) from the aqueous phase by an organic solvent (S) forming a solvate (M·nS), rearranged in the form –log a_M=y= log K+ log a_sⁿ/a_MS(a= chemical activity of species), has been used to determine K. The method is based on the appearance of an inflexion point in a plot of the experimental data as y= f(c_MS), where c denotes analytical concentration. The quotient a_Sⁿ/a_MS at the inflexion point can be substituted by an expression containing the total concentrations of the solvent and the compound extracted.