Prediction of multicomponent ion-exchange equilibria for a ternary system from data of binary systems

A framework is developed to provide predictions of multicomponent ion-excha nge equilibria from binary data. Our input data were taken from published e xperimental results on the ion-exchange equilibria of the binary systems Sr 2+-Na+, Cs+-Na+ and Sr2+-Cs+ on chabazite zeolite. These systems exhibit no nideal characteristics in both solid and liquid phases. The experimental ch aracterization has been based on the reaction equilibrium constants and the activity coefficients in both phases. The activity coefficients of the exc hanger phase were obtained from the well-known Wilson model. A computer pro gram was given in FORTRAN-77 to carry out the prediction procedure. The sum of the squares of differences between experimental and predicted points wa s used as a criterion for best fit. The model was also verified on systems involving the exchange of the anions SO4-, NO3-, and Cl- on Amberlite IR-40 0. The good agreement between the experimental and predicted data showed th at the proposed framework can be considered as an effective method to predi ct many ternary systems from binary systems.