Oxidation processes of aromatic sulfides by hydroxyl radicals in colloidal solution of TiO2 during pulse radiolysis

The pulse radiolysis technique has been used to elucidate the oxidation reaction of aromatic sulfides by hydroxyl radicals on the TiO2 nanoparticles in pH 2 aqueous solution. The hydroxyl radicals generated during the pulse radiolysis of the colloidal TiO2 aqueous solution were strongly adsorbed on the TiO2 particles with an apparent association constant (Kapp) of ∼106 M−1. The hydroxyl radicals trapped on the TiO2 surface exhibit the absorption spectrum with a maximum peak at 370 nm. In order to clear the oxidative ability of this species, the oxidation processes of 4-methylthiophenylmethanol (MTPM) and 2-phenylthioethanol (PTE) in the colloidal TiO2 aqueous solution have been examined based on the kinetic analysis of the transient absorption.