ION-EXCHANGE OF RADIUM AND BARIUM IN ZEOLITES

The sorption of radium, barium and mixtures of both elements has been studied in the zeolites 3A, 5A and Y. The ratio zeolite : solution was 100 mg : 10 cm(3) and the pH was 3. Carrier-free radium was completel y retained in all studied zeolites. When 0.0016 meg of barium/cm(3) we re added, the sorption of radium decreased in the zeolite 5A only and when 0.014 meq of barium/cm(3), the radium sorption was reduced in all the studied zeolites. The sorption of barium was similar to that of r adium. The amounts of sodium, potassium and calcium removed from the z eolites and the proton quantity fixed to them allowed us propose the i on exchange mechanism. The charges and ionic radii of the species exch anged did not play an important role. However, the location of the ion s in the crystalline network of each zeolite is probably an important parameter for the exchange.