Fe-modified TiO 2 photocatalysts for the oxidative degradation of recalcitrant water contaminants

Abstract

Fe–TiO 2 with enhanced photocatalytic oxidation activity was synthesized by hydrolysis of titanium butoxide. Sol–gel process leads to less active Fe–TiO 2 particles than bare TiO 2; meanwhile, the hydrothermal synthesis of Fe–TiO 2 seems to promote the stabilization of Fe 3+ in the TiO 2 structure promoting the photo-oxidation activity of TiO 2 towards the degradation of azo-dyes and the inactivation of Escherichia coli ( E. coli) in water. Photocatalysts were characterized by X-ray diffraction (XRD), diffusive reflectance spectrophotometry (DRS), and N 2 adsorption–desorption. The TiO 2 synthesized by the hydrothermal synthesis reaches the TiO 2 Degussa P-25 photo-oxidation activity towards the degradation of orange II. Furthermore, Fe loading of TiO 2 in hydrothermal synthesis improves remarkably the photoactivity of HT. The comparative performance of the photocatalysts towards the direct photo-oxidation of iodide, the photocatalytic degradation of orange II and the photocatalytic disinfection of water infected with E. coli suggested different mechanisms of oxidation: a surface-hole-oxidation mode for hydrothermally synthesized TiO 2 particles and a homogeneous phase oxidation mode promoted by OH radicals produced in the TiO 2 P25 surface.