Thermodynamics of interphase equilibrium in system ion exchanger-solution of low molecular weight electrolyte

In order to calculate the activity of ion exchange groups in the resin having monoionic form we used published reference data assuming that the activity of resin exchange sites and that of corresponding monomer are equal in the solutions with equal concentrations. For ion exchange resin in mixed form in equilibrium with the mixed solution of corresponding low molecular weight electrolytes the method of calculating each of ionic forms was also suggested. These activities were used to determine the constant of ion exchange equilibrium.