131I− sorption from aqueous solutions by nitrated hydrotalcites

The sorption of radioactive iodide anion from aqueous solutions on hydrotalcite in the nitrate form has been investigated as a function of the Al/(Mg+Al) ratio. It was found that I− can replace only a small fraction of the nitrates in hydrotalcites and that I− sorption depends highly on Al/(Mg+Al) ratio.131I− was sorbed by anion exchange in the interlayer of hydrotalcite with an Al/(Mg+Al) ratio of 0.20 and, for higher ratios,131I− sorption increased more than 3 times. Hydrotalcites in the nitrate form were prepared using microwave irradiation in the hydrotreatment step. The radionuclide content was determined by Γ-spectrometry. Solids were characterized by BET, X-ray diffraction and atomic absorption analyses.