Mechanism pathway and kinetics of p-cresol photocatalytic degradation over titania nanorods under UV-visible irradiation

Titania nanorods (TNRs) in pure anatase phase were synthesized by a hydrothermal technique and calcined at 450 degrees C. The material was characterized by X-ray diffraction (XRD), N-2 adsorption, transmission electron microscopy (TEM), UV-DR spectroscopy, and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of p-cresol was carried out under UV-vis irradiation. The photodecomposition of p-cresol could be expressed by pseudo-first order in Langmuir-Hinshelwood kinetic model. The rate constant obtained of the TNRS catalyst was higher than that over P25 catalyst. Intermediates produced during the reaction were 4-methylcatechol, 4-hydroxybenzoic acid, 4-hydroxybenzyl alcohol and 4-hydroxybenzaldehyde. All intermediates are indicated to be less hazardous compared to p-cresol. More than 96% TOC mineralization was achieved during the degradation time. In addition, the reaction mechanism and pathway has been proposed and the rate constants for each elementary reaction were evaluated. (C) 2016 Published by Elsevier B.V.