Degradation of contaminated industrial waste water using sol-gel derived Ru-doped TiO₂ photocatalyticfilms

In this study, Ru-TiO₂ films were deposited on glass substrates with a sol-gel route for degradation of contaminated industrial water. A solution with the Ru/Ti molar ratio of 0.05 was prepared using ruthenium and titanium based precursors. Solution characterizations were made using a turbidimeter and pH meter. The gel films, prepared by the sol-gel drop casting method, were dried at 300°C for 10 minutes and subsequently heat-treated at 500°C for 5 minutes in air. After that, the oxide thin films were annealed at 600°C for 60 minutes in air. In order to evaluate the phase structure, microstructure, optical, and photocatalytic properties of the coatings, they were investigated using XRD, SEM, and UV/Vis spectrophotometer, respectively. The obtained phase was mostly anatase TiO₂. Photo-oxidation experiments were performed to obtain the photocatalytic activity of the films on impure water using an UV light source. The absorption spectrum of the water samples taken from Cigli Industrial Plant and Gediz River in Izmir/Turkey showed that they have absorbance bands in the range of 300 nm and 500 nm. The Ru doped TiO₂ films exhibited highly photocatalytic activity to decompose organic species in contaminated waters. The degradation percentage ratios were calculated as 75% and 62% for two different industrial water samples.