New Insights on the heterogeneous photocatalytic removal of U(VI) in the presence of formic acid. Evidence of U(III) formation

M I LITTER; V. SALOMONE; J.M. MEICHTRY

Encuentro; 9th European meeting on Solar Chemistry and Photocatalysis: Environmental Applications (SPEA9); 2016

The efficiency of TiO2 heterogeneous photocatalysis under UV-visible light for removal of uranyl (0.25 mM, pH 3) in the presence of formic acid (HCOOH) was investigated. The effect of the counterion of the uranium salt (perchlorate and acetate+nitrate) was analyzed. The highest removal efficiency was observed for uranyl perchlorate with 0.001 M HCOOH. U(VI) photocatalytic transformation studied by direct spectrophotometry using transparent TiO2 nanoparticles in the presence of 1 M HCOOH at pH < 2 allowed the detection of U(V), U(IV) and U(III). U(III) formation was also apparent in similar conditions but in the absence of the photocatalyst. This is the first time that formation of U(III) in a photochemical U(VI) system is reported.