Kinetic model basis of ozone/light-based advanced oxidation processes: a pseudoempirical approach

Most works on AOP technologies aimed at removing contaminants from water have focused on the influence of experimental variables on the overall removal rate of specific target contaminants. Few studies have been devoted to proposing detailed kinetic models of these processes. Photocatalytic ozonation is a highly complex process, where commonly the number of unknown parameters, reactions, intermediates generated, etc. impedes the proposal of a detailed rigorous reaction mechanism. In this work, a pseudoempirical model based on experimental data and the typical reactions occurring during photocatalytic oxidation and ozonation of a model compound (primidone) has been proposed and discussed. Total organic carbon was selected as a surrogate parameter to simulate the process. The experimental system consisted of an ozonation tank where water was pumped to and recirculated through a tubular photoreactor equipped with 6 high power UVA LEDs. The photoreactor was characterized by non-ideal flow analysis and chemical actinometry. The model was implemented in Simulink (R) and solved to minimize differences between the model and experimental data. Simple processes such as ozonation, photolytic ozonation and photocatalytic oxidation were acceptably modelled and used to simulate the photocatalytic ozonation process.