AC/TiO2 granular photocatalysts optical properties: Material composition effect on the radiative transfer in a photoreactor

The radiative transfer analysis in photoreactor with heterogeneous media is still a challenge for reasons relative to solid particles structural complexity or materials complex optical properties. This article aims to study the radiative transfer in a photoreactor containing Activated-Carbon/Titanium Dioxide (AC/TiO2) composite particulate media. A focus was made on the analysis of the photon rate absorbed by these media, which is a key value for the further study of chemical photo-reaction for which they are intended into the system. The radiative properties of these media were first consistently defined using different mixing laws for refractive index calculation, coupled to Mie theory. A validation of the radiative properties was achieved by solving the radiative transfer equation using a Monte Carlo algorithm and by comparing the results of transmittance modelling of each media with transmittance experiments. The second part of the work consisted in the use of a second Monte Carlo algorithm for modelling local radiant energy repartition in the studied photoreactor and access the rate of energy absorbed. These parameters are some key tools for the description and the assessment of reactions in a defined photoreactor. An originality of the study comes from the wide range of AC/TiO2 composition studied through the work which allows to analyze the evolution of the radiative properties, radiant energy repartition and rate of energy absorbed as a function of the AC/TiO2 material composition.