Column Dynamics of Ternary Ion Exchange Part II: Solution Mass Transfer Controlling

Abstract

The nonequilibrium theory for column dynamics of multicomponent ion exchange has been evaluated using the ternary system Ag-Na-H at a total solution concentration of 0.05 N (0.05 M) so that solution mass transfer controls the exchange. Ternary mass transfer coefficients have been related to binary values by both simple (constant) and improved (concentration-dependent) Fick's law models, as well as by simple and improved Nernst-Planck models. Binary coefficients of all four types were obtained directly from constant-pattern binary breakthroughs and the individual-component Nernst-Planck coefficients were derived from the binary coefficients. Using each of the four models, ternary effluent concentration histories (ECH) were predicted using the method of characteristics. All the models predicted effluent concentration histories that matched closely the experimental ones, indicating that either model may be used satisfactorily for prediction; the simple models are preferred to the improved ones since they contain fewer parameters.