A study on dye photoremoval in TiO 2 suspension solution

Abstract

TiO 2 samples with different characteristics and adsorption ability were prepared via hydrolysis of titanium tetraisopoxide and calcination at four different temperatures. The photoremoval of Acid Red 3B catalyzed by these catalysts was carried out. The results show high firing temperature lead to large TiO 2 particle and a low adsorption ability of TiO 2. The dye photoremoval reaction fits zero order kinetics well in catalyst-free solution and changes to first order kinetics in the presence of TiO 2. The solution pH value has a large effect on the removal efficiency. High dye removal efficiency can be obtained at high pH value. Catalyst addition improves the dye photoremoval efficiency and leads to the change of removal kinetics. Anatase TiO 2 fired at 400 °C shows the best catalytic activity and the catalytic activity of TiO 2 fired at 800 °C, which is rutile, is the worst of all catalysts. The catalytic ability of TiO 2 is influenced mainly by two factors of catalysts: crystalline form and adsorption ability for Acid Red 3B. The crystalline form is a more important factor influencing the catalytic activity than the adsorption ability of TiO 2 and the catalytic activity can be enhanced by the high dye adsorption ability of TiO 2.