Photodegradation of reactive red 222 using TiO2 nanostructured thin films prepared by modified sol-gel method

In this paper, a modified sol-gel method using peroxotitanic acid sol (PTA) was applied for the preparation of TiO2 nanostructured thin films on glass plates. The peroxotitanic acid sol was synthesized using titanium isopropoxide, isopropylalchol, H2O and hydrogen peroxide. TiO2 films were then calcined at 500oC and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results showed that increasing the number of coated layers would lead to the formation of anatase phase at high level. Addition of Polyethylene Glycol (PEG) on the PTA sol could cause uniform coating without any cracks. The photocatalytic performance of the obtained films was investigated by the photodegradation measurements of Reactive Red 222 (RR222) in a batch reactor. For further investigations the effect of some parameters such as initial RR222 concentration, pH value, hydrogen peroxide addition and temperature on the photocatalytic performance of TiO2 thin films was studies as the important factors. Kinetic study results of this reaction represented that it obeys of was pseudo-first-order model. The degradation of RR22 was enhanced by the addition of optimum amount of hydrogen peroxide. This is due to the increasing amount of the radical hydroxyls.