Adsorption behavior of IO3− by CO32−- and NO3−-hydrotalcite

For the improvement of radioactive waste disposal, the materials with high adsorption capacity for IO3− should be used. Hydrotalcite-type (HT) compounds are considered potential materials. The adsorption behavior of IO3− by hydrotalcite-type compounds with CO3− (HTCO3) or NO3− (HTNO3) interlayer anions was studied. Adsorption equilibrium was reached more quickly for HTCO3 than for HTNO3. The adsorption isotherm for HTCO3 consisted of two Langmuir type adsorption processes. The desorption behavior was quite different for HTCO3–HTNO3. The results suggested that IO3− is adsorbed on the external surface of HTCO3 whereas IO3− is exchanged for interlayer NO3−.