Contribution to understanding iodine sorption mechanism onto mixed solid alumina cement and calcium compounds

An experimental study on the iodine sorption mechanism onto mixed solid alumina cement and calcium compounds was carried out. The solids were prepared by mixing the alumina cement with Ca(OH)2 and/or CaSO4·2H2O. Batch experiments were performed for iodine sorption onto the solid and iodine desorption from the solid that was obtained after a sorption experiment. In order to clarify the hydrates in the solids, X-ray diffraction measurement and scanning electron microscopic observation were adopted. The iodine sorption onto the solid proceeded to replace the OH- in 4CaO·Al2O3·13H2O by I- in solution to form the new hydrate, 3CaO·Al2O3·CaI2·12H2O. The results of sorption and desorption experiments showed that the iodine sorption proceeded reversibly and was independent of concentration of iodine up to 1x10-2 mole/dm3 in solution. (author)