Efficient Sol-gel Nanocomposite TiO2-clay in Photodegradation of Phenol: Comparison to Labe-made and Commercial Photocatalysts.

The degradation and mineralization of phenol have been studied by means of photocatalysis process using UV light (λ_max ≈ 365 nm). The investigated nanocompositephotocatalyst TiO₂-Py(750) (S_BET=16.58 m².g^{− 1}), with mixed phases of Anatase and Rutile (52.2/10.7), have been sol-gel synthetized and calcined at 750 °C using a decarbonatedpyrophyllite as layered clay and titanium (IV) t-butoxide, Ti(OCH₂CH₂CH₂CH₃)₄as precursor. Best results were achieved with TiO₂-Py(750), which showed great photo-activity than that of labe-made TiO₂ ECT1023t and commercial TiO₂AEROXIDE®P25. The influences of different operating parameters, like pH, H₂O₂ concentration, photocatalyst dose, on the photodegradation of phenol by UV/TiO₂-Py(750) system were examined. The TiO₂-Py(750) showed total degradation, detoxification and good TOC mineralization at optimum conditions (pH = 5, [H₂O₂] = 10 mmol.L^{− 1}, m = 2 g.L^{− 1}). The toxicity analysis was carriedout based on the inhibition of bioluminescence of the marine bacteria Vibrio fischeri. The title photocatalysts have been investigated by UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR) and BET specific surface area. [ABSTRACT FROM AUTHOR]