TERNARY AND QUATERNARY ION-EXCHANGE EQUILIBRIA

Using a semi-empirical model developed previously by the authors the c ation exchange equilibria within the ternary H+ - Na+ - K+ system, and the quaternary H+ - Na+ - K+ - Ca++ system were investigated. Non-ide alities in the solution phase are considered by applying Fitter's mode l for electrolyte behaviour while the resin phase activity coefficient s are calculated by applying Wilson's model. Using the equilibrium con stants and two binary interaction parameters determined experimentally for each of the constitutive binary systems, the equilibrium behaviou r for the ternary and quaternary are predicted. The average deviations are all of smaller magnitude than the experimental error for the tern ary and quaternary ion exchange systems studied.