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 photoc atalytic reactor has been experimentally determined by measuring the radiat ive fluxes coming into and going out of the reaction space through the glas s walls of a reactor. These radiative fluxes were obtained from experimenta l measurements made with precisely calibrated UV detectors. These values of the volume-averaged VRPA were used to decide the validity of theoretical c alculations obtained from the rigorous application of the radiative transfe r equation. Afterward, the reaction kinetic dependence with respect to the local Volumetric rate of photon absorption (LVRPA) and its effect on the qu antum yield evaluation were analyzed. To do this, the linear and square roo t reaction rate dependencies with the LVRPA were considered. Employing a ti tanium dioxide suspension, it has been demonstrated that (i) failing to pro perly account for radiation scattering in suspended solid photocatalytic re actors will normally lead to significant errors in the evaluation of the tr ue absorbed light and (ii) point values of the photon absorption rate are n ecessary in order to represent the true kinetics of the photocatalytic reac tion. The reason being the existence of very strong spatial nonuniformities in the above-mentioned rates.