Photocatalytic degradation of p-chlorophenol by hybrid H₂O₂ and TiO₂ in aqueous suspensions under UV irradiation

In this study, TiO₂ particles were used as photocatalysts for the degradation of aqueous p-chlorophenol (p-CP) under UV irradiation. The effect of TiO₂ dose (0-3g/L), initial p-CP concentration, H₂O₂ concentration (2-45mM), solution pH (4.6-9.5), and UV light intensity on the degradation of p-CP were examined. Four oxidative degradation processes, which utilized UV alone (direct photolysis), H₂O₂/UV, TiO₂/UV, and H₂O₂/TiO₂/UV, were compared in a batch photoreactor with a 100-W high-pressure mercury lamp. The photodegradation of p-CP could be described by the pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. Moreover, the apparent degradation rate constants increased considerably from 3.5×10^-3min^-1 (direct photolysis) to 19.9×10^-3min^-1 (H₂O₂/TiO₂/UV system).