Search

The study concerns the photo-oxidation of pollutants in a photo-reactor containing a TiO2 type catalyst. We modeled caffeine degradation, a persistent pollutant, in a continuous-flow photo-reactor undergoing time-variable incident irradiation conditions. The model is a mass balance in which the degradation reaction rate of caffeine is an empirical law, function of both pollutant concentration and of the local volumetric rate of photon absorption. This latter was determined by resolving the radiative transfer equation via a Monte-Carlo method and using Mie theory as a tool to define the medium radiative properties. Kinetic constants were identified via a parametric optimization study based on batch mode caffeine degradation experiments with varying incident flux density. The model was validated to represent the treatment capacity of the continuous-mode process under the constant incident flux density conditions applied. It was also successfully used to represent process treatment capacities and efficiencies under time-variable simulated irradiation conditions representative of typical Summer and Winter days. This study is therefore a first step for the prediction of treatment capacity and efficiency of continuous mode solar processes undergoing intermittency and fluctuating light.