Adsorption of technetium on selected inorganic ion-exchange materials and on a range of naturally occurring minerals under oxic conditions

Abstract

The adsorption of Tc 95m, as TcO 4 −, on a weakly basic organic ion-exchange resin was studied as a function of pH in 0.1M solutions of Na 2SO 4, NaCl and NaNO 3. A similar study was performed with the adsorbents ZrO 2 and Al 2O 3. In addition, adsorption on ZrO 2 was investigated in 0.01 and 0.25M NaCl. An unusual pH profile of the distribution coefficient was found for the polymer, [(CHg 3O)Cl] n in 0.1 and 1M NaCl and 0.1N Na 2SO 4, in as much as the D values increased with pH rather than decreased as was observed in all prior examples. In a number of selected systems, the adsorption of I 131, as I −, was studied to aid in the characterization of the mechanisms. In addition, the adsorption properties of 37 minerals with respect to TcO 4 − were investigated in 0.1M NaCl as a function of pH. For the minerals, montmorillonite, illite, kaolinite and monazite this work was expanded to include 0.01, 1.0 and 4.0M NaCl solutions. In general, the distribution coefficients observed under the oxic conditions employed here were small and could be adequately accounted for by an ion-exchange mechanism.