Photocatalytic Reduction of Selenate and Selenite Solutions Using TiO2 Powders

The photocatalytic reduction of aqueous solutions containing Se(VI) and Se(IV) was studied using TiO2 powders and an HCOOH reductant. Without the addition of a suitable reductant and UV irradiation, no significant reduction of Se(VI) and Se(IV) can proceed. The ability of Se ions to be adsorbed onto TiO2 is an important factor in the ease of reduction of these ions. Elemental Se is directly produced from both Se(VI) and Se(IV) solutions. The maximum yield of elemental Se never reaches 100 pct, due to the initiation of H2Se generation.