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Abstract

Nano-porous titanium oxide coatings were produced on titanium of commercial purity by anodization in methanolic electrolytes. The structure of the oxide was found to be amorphous. Following heat-treatment at 400°C for 20 min the amorphous oxide crystallized and was transformed into anatase. Application of this coating as a catalyst for the destruction of cyanide ions in aqueous solutions under ultraviolet radiation was investigated. The effects of process parameters, such as oxide crystallinity (amorphous versus anatase), ultraviolet intensity and oxygen exposure, on the rate of cyanide destruction were studied. Anatase exhibited superior photocatalytic activity to the amorphous form of TiO₂. The poor activity of amorphous TiO₂ was attributed to the recombination of photo-excited electrons and holes at defects located on the surface and in the bulk of the coatings. As expected, oxygen was found to play a critical role in the destruction of the cyanide.

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Photocatalytic oxidation of cyanide ions by alkoxy-derived titanium oxide coatings

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