Photocatalytic oxidation and removal of arsenite by titanium dioxide supported on granular activated carbon.
Arsenic contamination in drinking water is a worldwide concern. Photocatalysis can rapidly oxidize arsenite, i.e. As(III), to less labile arsenate, i.e. As(V), which then can be removed by adsorption on to various adsorbents. This study investigated the photocatalytic oxidation of arsenite in aqueous solution by granular activated carbon supporting a titanium dioxide photocatalyst (GAC-TiO2). The effects of photocatalyst dosage, solution pH values, initial concentration of As(III) and co-anions (SO4(2-), PO4(3-), SiO3(2-) and Cl-) on the oxidation of As(III) were studied. The photocatalytic oxidation of As(III) took place in minutes and followed first-order kinetics. The presence of phosphate and silicate significantly decreased As(III) oxidation, while the effect of sulphate, chloride was insignificant. The oxidation efficiency of As(III) was observed to increase with increasing pH. The results suggest that the supported photocatalyst developed in this study is an ideal candidate for pre-oxidation treatment of arsenic-contaminated water.
Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China; bSchool ofApplied Chemistry, Shenyang University of Chemical Technology, Shenyang 110142, China.
Shu Hua
SH
Yao
Yong Feng
YF
Jia
Shan Lin
SL
Zhao
D018053:Arsenites / Q000302:isolation & purification*; D002606:Charcoal; D010084:Oxidation-Reduction; D010782:Photolysis; D014025:Titanium / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D018053:Arsenites; C009495:titanium dioxide; D002606:Charcoal; D014025:Titanium; C015001:arsenite