Photo-oxidation of an endocrine disrupting chemical o-chloroaniline with the assistance of TiO2 and iodate: Reaction parameters and kinetic models

• The UV/TiO2/KIO3 system is efficient in photo-oxidation of o-ClA.
• The KIO3 has a significant influence, which is more critical than TiO2.
• The decay follows two stage pseudo first-order kinetics with fast k1 and slow k2.
• Kinetic models are successfully derived in terms of [KIO3]0, [TiO2]0 and pH levels.
• Kinetic models offer efficient approaches to predict o-ClA decay in this system.

An efficient photo-oxidation system was introduced to decay a typical endocrine disrupting chemical o-chloroaniline (o-ClA) by using UV light with the assistant of TiO2 and IO3− (UV/TiO2/KIO3 system). The o-ClA decay in UV/TiO2/KIO3 system is much superior to sole UV and UV/TiO2. For depth evaluating the system, the effect of TiO2 dosages, KIO3 dosages, and initial pH levels ([TiO2]0, [KIO3]0 and pH0) were investigated and optimized. The optimum o-ClA decay was achieved at [KIO3]0 of 66.7 mg/L and pH0 of 7.09. The kinetics analysis showed that the o-ClA decay followed a two-stage pseudo first-order, and the decay rate constants at both stages (k1 and k2) are significantly influenced by [TiO2]0, [KIO3]0 and pH0. After data analysis, both 1/k1 and 1/k2 were found linearly correlated to [KIO3]0, pH0 and 1/[TiO2]0. Mathematic models were therefore derived for predicting o-ClA decay in terms of [TiO2]0, [KIO3]0 and pH0. Moreover, the proposed models offered efficient approaches to predict the o-ClA decay in UV/TiO2/KIO3 system under various conditions.