Simplified Model for the Hydrodynamics and Reaction Kinetics in a Gas−Liquid−Solid Three-Phase Fluidized-Bed Photocatalytic Reactor: Degradation of o-Cresol with Immobilized TiO2

Abstract

The hydrodynamics and reaction kinetics in gas−liquid−solid three-phase fluidized-bed photocatalytic reactors were examined. The effects of initial o-cresol concentration, intensity of UV light, catalyst loading and size of TiO2 photocatalyst, and the dispersion of catalytic particles on the degradation rate of o-cresol used as a model pollutant were examined. The photocatalytic decomposition of o-cresol was reasonably described by the Langmuir−Hinshelwood kinetics. The rate constant of photocatalytic degradation was found to be proportional to TiO2 surface area and the square root of UV light intensity. For the design and scale-up of an external light irradiation fluidized-bed photoreactor, a phenomenological model was developed. The simplified model for the average light intensity was linked to a one-dimensional sedimentation−dispersion model describing catalyst particles concentration profiles in the photoreactor and then to the reaction kinetics. The sedimentation−dispersion model could reasonably des...