Decolorization of cationic yellow X-Gl 200% from textile dyes by TiO 2 films-coated rotor

Abstract

Application of titanium dioxide (TiO2) films-coated rotor for treatment of wastewater from textile dyes was investigated under photocatalytic activity. This study, TiO2 films were prepared by sol-gel technique from titanium tetraisopropoxide and isopropanal of 1:15 and 1:20 (V/V) and adjusted to pH = 2 by using nitric acid. The TiO2 films were coated on 6-paddles grade 304 stainless steel of rotor by dip coating of 10, 15 and 20 cycles. After deposition, TiO2 films were treated at annealed temperature of 500 °C. All TiO2 films showed anatase phase-structure. The experiments consist of two parts, in the part 1, the influence of titanium tetraisopropoxide and isopropanol ratio and number of TiO2-coating cycles were investigated. In the part 2, efficiencies of decolorization by using coated TiO2 samples and uncoated TiO 2 samples were investigated. Cationic yellow X-Gl 200% that had concentration 100 mg/L were used as wastewater from textile dyes. From, photocatalytic test by using Cationic yellow X-Gl 200% solution and immersed coated TiO2 samples and uncoated TiO2 samples in upon solution, showed that titanium tetraisopropoxide and isopropanal of 1:20 and number of TiO2-coating cycles of 20 cycles was the best condition. Then, used the best condition to prepare the TiO2 films-coated rotor. The TiO2 films-coated rotor and Cationic yellow X-Gl 200% were irradiated under UV-A at middle wavelength of 365 nm with irradiation times at 1 2 and 3 days. The result showed that TiO2 films-coated rotor had decolorization efficiencies of 95.53, 95.84 and 99.14% for irradiation times at 1, 2 and 3 days, respectively. The efficiency of decolorization is better than uncoated-TiO2 surface about 90%. In this way, the photocatalytic degradation process by using coated rotor of TiO2 film as a photocatalyst and UV-A light as an irradiation source showed potential application for the decolorization of wastewater from textile dyes. © 2010 Published by Elsevier Ltd.