engleski

Enhancing photocatalytic activity of the sol-gel TiO2 film by polyethylene glycol addition on example of azo-dye: effects of reaction temperatures and irradiation wavelengths

Two different nanostructured sol-gel TiO2 films were prepared on a glass substrate by means of the dip-coating technique with titanium tetraisopropoxide as a precursor: with and without of polyethylene glycol (PEG) as a structure-directing agent. The synthesized films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD) method, thermal gravimetry (TG) and differential scanning calorimetry (DSC). The TiO2 film prepared with the addition of PEG has a higher ratio of antase/rutile crystalline phases and higher roughness parameters. The photocatalytic activity of the films was evaluated by the photocatalytic degradation of Congo Red dye (CR) with the radiation wavelengths of 365 nm (UV-A) and 254 nm (UV-C). The temperature effects (17.5, 25 and 35 °C) on the reaction rate were followed for each wavelength and for each TiO2 film. TiO2 film with the addition of PEG showed higher photoactivity. Higher degradation rates were observed with UV-C than with UV-A radiation, mostly due to the simultaneous photolytic and photocatalytic processes and at higher reaction temperatures. Photocatalytic activities of the films were monitored by means of UV/VIS spectrophotometry, total organic carbon (TOC), LC/MS/MS and ion chromatography (IC).

Congo red dye; photocatalytic degradation; polyethylene glycol; reaction temperature; sol-gel TiO2 film; UV radiation

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