Photocatalysis and H2O2/UV-C - Application to nuclear wastes
Résumé
The efficiency of photocatalytic methods based on TiO2 (Degussa P-25) and UV/H2O2 as
means of degrading, mineralizing Ethylenediaminetetraacetic acid (EDTA) alone or
complexes with radioelement and recovering the radioelement (Co) were studied under
UV-C irradiation. EDTA was chosen because it is present in high proportions at nuclear
facilities, where it is used for cleaning and decontamination purposes because of its
chelating properties. In a first step the photonic flux of the UV-C lamps was established
using actinometric and Keitzâs methods. Then adsorption capacities of TiO2 to adsorb
Co complexes or not with EDTA have been studied. Finally, we compared the
disappearance and mineralization rates, the intermediate by-products formed in the
degradation of EDTA under UV-C photolysis, photocatalysis and H2O2/UV-C and studied
the effect of pH. The results show that the efficiency of the UV/TiO2 and UV/H2O2
processes was found to be similar, provided H2O2 was added continuously during the
UV/H2O2 process. The photonic efficiency was calculated and found to be equal to 0.9%
in the case of photocatalysis and 1.4% in that of UV/H2O2