A Kinetic Study of Photocatalytic Degradation of Phenol over Titania–Silica Mixed Oxide Materials under UV Illumination

Abstract

A set of titania–silica mixed oxide materials were prepared by a cosolvent-induced gelation method using ethanol and toluene as solvent and cosolvent, respectively. These materials were extensively characterized by utilizing several characterization techniques and assessed for phenol degradation under UV illumination. The degradation of phenol follows first-order kinetics, and fragmented products formed during the phenol degradation were qualitatively identified by using high performance liquid Chromatographic (HPLC) and atomic pressure chemical ionization mass spectroscopic (APCI-MS) techniques. The complete mineralization of phenol was further evidenced by the measurement of the total organic contents that remained in the solution after irradiation. The pore diameter of the materials was found to be the key factor for phenol degradation, whereas surface area and pore volume play a role among the mixed oxide materials. In addition, in the mixed oxide system there was an inverse correlation obtained with the particle size of the materials and the degradation efficiency. The smaller particle size of titania in the mixed oxide material was found to be a requirement for an effective degradation of phenol.