Effects of humic acids on the photoinduced reduction of U(VI) in the presence of semiconducting TiO2 particles.
The effects of Humic Acids (HA) on the photoinduced reduction of U(VI) in aqueous suspensions containing titanium dioxide particles was investigated by Time-Resolved Laser Induced Fluorescence in the pH range 5 to 7. The fluorescence response was of both aqueous phase and adsorbed U(VI) species was also analyzed. The rate of the aqueous phase U(VI) photo-reduction was found to be enhanced by U(VI) complexation with HA. A photo-sensitizing effect of HA on the interface reaction was evidenced at high irradiation intensity, with the HA pre-filter effect prevailing at low irradiation. A kinetic model was developed, which takes into account U(VI) photo-reduction occurring both in the aqueous phase and at the semiconductor oxide - water interface, as well as adsorption and re-oxidation reactions.
Bibliographic Reference: Article: Environmental Science and Technology
Availability: Environmental Science and Technology (Journal)
Record Number: 200012024 / Last updated on: 2000-06-14
Original language: en
Available languages: en