Advanced oxidation processes (AOP) have been proposed as an effective treatment method for organic contaminants in water and wastewaters. Among them, UV/H2O2 has shown great potential for the destruction of a wide range of persistent organic contaminants. The UV/H2O2 process comprises direct photolysis, where the target compound is transformed through absorbing UV photons, and indirect photolysis, where the compounds react with OH radical produced via photolysis of H2O2. Whereas direct photolysis rate is controlled by two factors, i.e. the molar absorption coefficient and the quantum yield, indirect photodegradation rate depends on the formation of oxidant species, i.e. the hydroxyl radical, and radical scavengers in the background water.
In this study, photodegradation of parathion both by direct UV and the UV/H2O2 oxidation process were investigated. The objectives of this study were to: (i) elucidate the parathion UV photodegradation kinetics, and (ii) understand the degradation mechanism through the analysis of various byproducts. Both low pressure (LP) UV lamps and medium pressure (MP) UV lamps were evaluated