Experimental measurement and modeling of the distribution of solvent and ions between an aqueous phase and an ion exchange resin

The distribution of solutes and solvent between an aqueous solution of salt and an ion exchange resin has been measured at ambient temperature. The experiments have been performed for aqueous solutions of KNO3, KCl, Ca(NO3)2 and CaCl2 in the concentration range of 0-3N. The absorption has been measured for three gel-type and three macroreticular resins with a degree of cross-linking varying from 10.5 to 18.5%. The experimental results have been modeled with the Extended UNIQUAC model combined with an elastic term taking the elastic properties of the resin structure into account. The model shows very good predictions with varying degree of cross-linking, and the deviations between model results and experimental data are all within the experimental error.