Degradation of a cobalt(II)-EDTA complex by photocatalysis and H2O2/UV-C. Application to nuclear wastes containing Co-60

K. Rekab , C. Lepeytre , F. Goettmann , M. Dunand , C. Guillard (1) , J. M. Null Herrmann (1)

1 CARE - IRCELYON-Catalytic and Atmospheric Reactivity for the Environment

The Co-60 present in some low-level effluents forms complexes with organic ligands such as ethylenediaminetetraacetic acid (EDTA). These complexes make it difficult to remove the Co-60 using conventional filtration methods. The aim of this study was to test the use of titanium-based photocatalysis (TiO2/UV) and photochemical methods involving the use of oxidation agents (H2O2/UV-C) (both of which are advanced oxidation processes) to degrade EDTA and recover Co-60 once it has been released from the complex. In preliminary experiments on the Co-59-EDTA complex, we tested the efficiency of the TiO2/UV and H2O2/UV-C processes as means of degrading EDTA molecules and releasing cobalt in its cationic forms Co2+ and Co3+. These cations can be trapped by either precipitating and/or adsorbing them on TiO2 depending on the pH. When this treatment was applied experimentally to radioactive wastes, it turned out to be highly effective since it improved the decontamination factor (DF: initial volumic activity/final volumic activity) twofold.

Domaines: Catalyse; Environnement et Société

K. Rekab, C. Lepeytre, F. Goettmann, M. Dunand, C. Guillard, et al.. Degradation of a cobalt(II)-EDTA complex by photocatalysis and H2O2/UV-C. Application to nuclear wastes containing Co-60. Journal of Radioanalytical and Nuclear Chemistry, 2015, 303 (1), pp.131-137. ⟨10.1007/s10967-014-3311-y⟩. ⟨hal-01149290⟩