Chinese Journal of Chemical Engineering, Vol.26, No.3, 529-533, 2018
Indirect photocatalytic reduction of arsenate to arsenite in aqueous solution with TiO2 in the presence of hole scavengers
The indirect photocatalytic reduction of arsenate to arsenite in aqueous solution with titanium dioxide (TiO2) was investigated with various hole scavengers such as methanol, ethanol, 2-propanol, formaldehyde, acetone, formic acid and acetic acid. Although the direct photocatalytic reduction of arsenate to arsenite with TiO2 was impossible, an indirect reduction of As(V) was possible in the presence of sacrificial electron donors to form strongly reductive radicals. The addition of ethanol was very effective for indirect photocatalytic reduction of As(V) in aqueous solution with TiO2 photocatalyst. The indirect photocatalytic reduction rate of As(V) may be related with both the reaction rate constants of reaction of hydroxyl radicals with hole scavenger and the reactivities for the radicals M center dot which are produced by the reaction of center dot OH with hole scavenger. (C) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.