Phenol destruction by photocatalysis on TiO2: an attempt to solve the reaction mechanism

Six hydroxylated aromatic compounds, p-benzoquinone and four aliphatic compounds were detected as intermediates of the reaction of phenol photocatalytic oxidation in the presence of illuminated TiO2. The concentration of catechol, hydroquinone and p-benzoquinone was determined quantitatively along with that of phenol in the course of the photoreaction. The reactions of TiO2-photooxidation of phenol and its primary intermediates—dihydroxybenzenes show 1st order behaviour. The use of initial reaction rates for kinetic studies is recommended because of many competitive reactions in illuminated suspensions of titanium dioxide. A possible mechanism of phenol full mineralisation is presented.

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