Chlorobenzene Degradation Assisted by TiO2 under UV Irradiation in Aqueous Solutions

We report the photocatalytic degradation of chlorobenzene (CB) in suspended TiO2 aqueous solution at pH7 under UV irradiation. We measured the kinetics of CB degradation and Cl- release and calculated a pseudo-first-order rate constant in both cases. We found a higher value of the rate constant kCB than of kCl- one, which show that the dechlorination does not take place concomitantly with the OH attack on CB. This oxidation reaction obeyed Langmuir-Hinshelwood equation. The half life time value resulted from this equation was lower than that of the pseudo-first order rate constant at any CB initial concentration. This showed us the existence of competition between the byproducts and the pollutant for OH radical consumption. Also, we demonstrate the positive effect of doped S-TiO2 on CB photocatalytic degradation (powder or film) due to its enhanced absorption in UV and in addition to a new absorption band in visible.