Fe/TiO2 ve Fe/TiO2–Ce katalizörler üzerinde ultrases destekli foto-fenton tipi reaksiyon ile reactive yellow 84 (RY 84)'ün parçalanması

In this study, a hybrid process which is a combination of heterogeneous Fenton Process with Photocatalysis in the presence of ultrasound (US), "Heterogeneous SonophotoFenton Process", was used to degrade Reactive Yellow 84 (RY 84) dissolved in water by using TiO2 and TiO2-Ce catalysts containing iron. The catalysts were prepared by sol-gel and incipient wetness impregnation methods and characterized by XRD, SEM, FTIR, Nitrogen adsorption, UV-Vis DRS and ICP-AES measurements. The catalysts were tested in the sonophotoFenton degradation of RY 84 in order to determine the most effective catalyst for decolorization and mineralization of RY 84. The TiO2 catalyst containing 1% (in weight) iron, prepared by incipient wetness impregnation technique and calcined at 300°C (1%Fe/TiO2 (IW) 300°C) was found to be the most effective catalyst. The effect of individually, binary and ternary combinations of advanced oxidation techniques including catalyst, UV, US and H2O2 were studied on the degradation of RY 84. Parametric study of sonophotoFenton process was carried out over 1%Fe/TiO2 (IW) 300°C catalyst and the effects of H2O2 concentration, initial pH of solution, initial dye concentration, temperature, catalyst amount and ultrasonic power were studied on the degradation of dye. Stability and recycling of the catalyst were investigated. Optimum degradation conditions for the sonophotoFenton process were determined as, 25 mg/L of RY 84 solution, 0.5 g/L of catalyst, 5 mM of H2O2, a temperature of 25°C, 4W+ 4W UV-C lamp and 40 W of ultrasonic power. Decolorization of RY 84 obeyed first order kinetics with an activation energy of 20.7 kJ/mol. At the obtained optimum conditions, with the sonophotoFenton oxidation of RY 84 almost complete color removal (99%), 55% COD, and 38% TOC reductions were obtained after 45 min of oxidation. At the end of the 120 min of oxidation, COD and TOC reductions increased to 90% and 57%, respectively. At the same conditions with the UV+catalyst+H2O2 oxidation of RY 84, it was possible to achieve almost complete (99%) color removal, 62% COD reduction, and 48% TOC reduction after 45 min of reaction. After 120 min COD reduction increase to 87%, however, TOC reduction remained constant after 45 min with combined system of UV+catalyst+H2O2.