Some examples of the use of amphoteric ion-exchange resins for inorganic separations

The usefulness of the amphoteric ion exchange resin Retardion 11A8, as well as, the chelating ion exchanger Chelex 100 for the separation of inorganic ions is demonstrated. The ion exchange method for selective separation of cadmium from other elements exploiting both anion-and cation-exchange function of Retardion 11A8 is presented. Conditions which should be met in order to retain, as well as, remove cadmium from the column are discussed. The ion exchange behaviour of about 20 elements on Chelex 100, depending on pH, as well as, concentration of HCl and NH3, respectively was studied. Results of the above investigations allowed the development of several interesting separations of some metal ions, where not only cationic (chelating) but also anionic function of the resin was employed. (C) 1997 Elsevier Science B.V.