Solar Photocatalytic Decolorization of Four Commercial Dyes in Aqueous Solution of Two Forms of Titanium Dioxide TiO2

Abstract

The photocatalytic decolorization of four commercial dyes with different structures and different substitute groups has been investigated using pure TiO2 and TiO2 sol-gel as photocatalysts in aqueous solution under solar radiation. Influence of different kinds of dye and photocatalyst on photo-catalytic process was studied. Solution temperature and daily photon flux during experiment was calculated. The result decolorization percentage of four dyes was in the following order: reactive yellow > methylene blue > tubantin blue > tubantin red; this is due to molecular structural difference among these four molecules of dyes. High decolorization when used TiO2 sol-gel due to small particle size, small surface area and wide energy gab. The daily photon flux average was nearly constant during the experiments, owing to its large surface area pure TiO2 caused higher average solution temperature than caused by TiO2 sol-gel when they are used as potocatalytic decolorizers.