Radiotracer studies on adsorption of iodide ions on thorium oxide

The kinetics of adsorption of iodide ions from bulk to the surface of thorium oxide has been studied by labelling the KI solution with 131I in different concentration range 10-12 M to 10-3 M, at different pH values of KI solution (3.5 to 10.1) and after irradiating the oxide sample for 12 to 48 hours by 300 mc (Ra-Be) neutron source. The adsorption obeys Freundlich adsorption isotherm and the kinetics of adsorption is found to be of first order. The effect of irradiation with neutrons and γ-rays on the adsorbent and the variation in pH of the solution influence the extent of adsorption and the rates show first order kinetics in both the cases. (auth.)