Evaluation of radiation absorption in slurry photocatalytic reactors. 2. Experimental verification of the proposed method

The volume-averaged volumetric rate of photon absorption (VRPA) in a photocatalytic reactor has been experimentally determined by measuring the radiative fluxes coming into and going out of the reaction space through the glass walls of a reactor. These radiative fluxes were obtained from experimental measurements made with precisely calibrated UV detectors. These values of the volume-averaged VRPA were used to decide the validity of theoretical calculations obtained from the rigorous application of the radiative transfer equation. Afterward, the reaction kinetic dependence with respect to the local Volumetric rate of photon absorption (LVRPA) and its effect on the quantum yield evaluation were analyzed. To do this, the linear and square root reaction rate dependencies with the LVRPA were considered. Employing a titanium dioxide suspension, it has been demonstrated that (i) failing to properly account for radiation scattering in suspended solid photocatalytic reactors will normally lead to significant errors in the evaluation of the true absorbed light and (ii) point values of the photon absorption rate are necessary in order to represent the true kinetics of the photocatalytic reaction. The reason being the existence of very strong spatial nonuniformities in the above-mentioned rates.