Use of SiO2 - TiO2 Nanocomposite as Photocatalyst for the Removal of Trichlorophenol: A Kinetic Study and Numerical Evaluation

Abstract

A series of silica-titania nanocomposite materials with different silica–titania ratios was prepared in presence of a novel ethoxylated sulphanilamide of molecular weight 1053 by the sol-gel method. Several characterisation techniques were adopted such as thermal analysis (differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA)), N₂-adsorption-desorption, X-ray diffraction (XRD), Fourier transform infrared (FTIR), and transmission electron microscopy (TEM) connected with energy dispersive spectroscopy (EDS). The surface acidity was investigated by pyridine adsorption using FTIR spectroscopy. The photocatalytic activity and the adsorptive ability of the composites were evaluated based on the photodegradation of 2, 4, 6- trichlorophenol (TCP) under UV irradiation with a wavelength of 254 nm. The maximum TCP adsorption onto the composites was measured in darkness. The results showed that there was no adsorption of TCP on pure SiO₂. The 10% TiO₂-SiO₂ catalyst showed the highest rate of TCP removal among the synthesised composites. The removal % reached to 87 % after 90 min irradiation time. This activity was caused by the large surface area and pore volume as well as the formation of a mesoporous structure, as evidenced from the pore size distribution curve. Finally, the numerical evaluation of the photodegradation of TCP was conducted.

Keywords: Nanocomposite, Ethoxylated sulphanilamide, Photocatalytic degradation, UV irradiation, 2,4,6-TCP, Numerical evaluation.