Mathematical modelling of phenol photooxidation: Kinetics of the process toxicity

This work reports the kinetic analysis of the photochemical degradation of phenol making use of the evolution of parameters such as the total organic carbon (TOC), toxicity of the treated water (TU), and oxidant concentration H2O2. The experimental study was carried out working with an initial concentration of phenol of 1000 mg L^−1, with a constant flux of radiation of 8.8×10^−5 einstein s^−1 and a variable initial concentration of the oxidant in the range between 17 000 mg L^−1 and 51 000 mg L^−1. The obtained results of TOC fitted to a first order kinetic law whereas zero order kinetics was found to describe H2O2 evolution. The decrease of the toxicity followed a constant trend related to TOC, being the ratio TU/TOC dependant on the initial H2O2 concentration.