I-131(-) sorption from aqueous solutions by nitrated hydrotalcites

The sorption of radioactive iodide anion from aqueous solutions on hydrotal cite in the nitrate form has been investigated as a function of the Al/(MgAl) ratio. It was found that I- can replace only a small fraction of the ni trates in hydrotalcites and that I- sorption depends highly on AII(Mg+Al) r atio. I-131(-) was sorbed by anion exchange in the interlayer of hydrotalci te 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 prepare d 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.