Pure and Sb-doped ZrO 2 for removal of IO 3 − from radioactive waste solutions

Radioactive 129 I with a long half-life (1.57 × 10 7 y) and high mobility is a serious radiohazard and one of the top risk radionuclides associated with its accidental and planned releases to nature. The complex speciation chemistry of iodine makes its removal a complicated task, and usually a single method is not able to remove all iodine species. Especially its oxidized form iodate (IO 3 − ) lacks a selective and effective removal method. Here, the granular aggregates of hydrous zirconium oxides with and without antimony doping were tested for IO 3 − removal and the effects of contact time, competing anions in different concentrations and pH were examined. The materials showed high selectivity for IO 3 − ( K d over up to 50,000 ml/g) in the presence of competing ions and relatively fast uptake kinetics (eq. < 1 h). However, B(OH) 4 − and SO 4 2− , as competing ions, lowered the iodate uptake significantly in basic and acidic solution, respectively. The suitability of the materials for practical applications was tested in a series of column experiments where the materials showed remarkably high apparent capacity for the IO 3 − uptake (3.2–3.5 mmol/g). Graphic abstract