Removal of cyanides in wastewater by supported TiO2-based photocatalysts

Abstract

Titania supported samples on different types of silica have been prepared through a sol-gel method followed by hydrothermal processing. The photocatalytic activity of the samples was tested for free cyanides photo-oxidation. As compared to commercial TiO2 all the synthesized materials showed not only similar photocatalytic efficiencies but improved recovery properties. The degradation of iron (III) cyanocomplexes was also studied in the absence or presence of titania catalyst. In all cases, a photoinduced CN¿ released from the complex takes place through a homogeneous process. The further oxidation of those cyanides ions to cyanate species is significantly enhanced in the presence of the catalyst in which mesostructured SBA-15 silica is used as support.