Radiation modeling and performance evaluation of a UV-LED photocatalytic reactor for water treatment

A photocatalytic reactor under UV-LED illumination is presented. It is an annular, packed-bed reactor filled with TiO2-coated glass rings. The reactor is irradiated both internally and externally in order to minimize the presence of dark zones. The knowledge of the radiation distribution inside the reactor is a key aspect to optimize its design and improve its efficiency. A three-dimensional model has been developed to describe the distribution of the local rate of photon absorption inside the reactor. The Monte Carlo method was applied to solve the radiation model. Simulation results were validated with experimental measurements. The model was able to predict the influence of the catalyst film thickness and the illumination conditions on the radiation distribution and on the total rate of photon absorption. Also, degradation assays of the pharmaceutical clofibric acid were carried out in the reactor and the performance of different illumination conditions was evaluated by means of the quantum efficiency parameter.