Comparative study on the effects of {2 0 1} TiO2 and {2 0 1}TiO2−ZrO2 on arsenite photocatalysis

Escalated levels of arsenic (As) in drinking water is an urgent environmental problem that has attracted increasing public concern. The need for effective removal of As has motivated great research efforts. Herein, {2 0 1} TiO2 and its Zr doped composite were compared in reducing As toxicity via photocatalysis. Macroscopic photocatalytic kinetics show that the oxidization process of As(III) catalyzed by {2 0 1} TiO2, { 20 1}TiO2−ZrO2, and ZrO2 followed first-order kinetics with a rate constant of {2 0 1} TiO2 >{2 0 1}TiO2−ZrO2 > ZrO2. UV–vis DRS and photoluminescence results suggested that the photooxidizing activity of {2 0 1} TiO2 outdone {2 0 1}TiO2−ZrO2 due to its narrower band gap and higher electron-hole separation efficiency. After 190 min of UV irradiation, the quantum yields of •OH during {2 0 1} TiO2 and {2 0 1}TiO2−ZrO2 photocatalysis were 146.1 and 112.6 μM, respectively. As evidenced by the radical-scavenging test, photocatalytically generated h+ and O2•- were the predominant participants in As(III) photooxidation for {2 0 1} TiO2 and {2 0 1}TiO2−ZrO2, respectively. The photocatalytic mechanism gained from the investigation would be helpful for developing high-index TiO2-based environmental techniques.