Photocatalytic reduction of dichromate by titanium dioxide supported on hollow glass microbeads

The photocatalytic reduction of dichromate using TiO2/beads as a photocatal yst was studied. The results showed that 3.8 x 10(-4) mol/dm(3) of dichroma te can be completely reduced into Cr3+ after illumination for 35 min with a 375 W medium pressure mercury lamp. The effects of factors such as the amo unt of TiO2/beads, initial concentration of dichromate, initial pH, nitroge n and oxygen atmosphere, and concentration of Fe3+ on the photocatalytic re duction of dichromate were investigated. A possible mechamism of the photoc atalytic reaction was proposed. After illumination for 200 h, no significan t loss of photocatalytic activity of TiO2/beads was observed.