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 AII(Mg+Al) ratio. I-131(-) was sorbed by anion exchange in the interlayer of hydrotalcite with an Al/(Mg+Al) ratio of 0.20 and, for higher ratios, I-131-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 gamma-spectrometry. Solids were characterized by BET, X-ray diffraction and atomic absorption analyses.