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

The photocatalytic reduction of dichromate using TiO₂/beads as a photocatalyst was studied. The results showed hat 3.8 × 10⁴ mol/dm³ of dichromate can be completely reduced into Cr³⁺ after illumination far 35 min with a 375 W medium pressure mercury lamp. The effects of factors such as the amount of TiO₂/beads, initial concentration of dichromate, initial pH, nitrogen and oxygen atmosphere, and concentration of Fe³⁺ on the photocatalytic reduction of dichromate were investigated. A possible mechanism of the photocatalytic reaction was proposed. After illumination for 200 h, no significant loss of photocatalytic activity of TiO₂/beads was observed.