Design and Evaluation of a Novel Light-Emitting Diode Photocatalytic Reactor for Water Treatment

Abstract

In this paper, an ultraviolet light emitting diode–based immobilized photocatalytic reactor was designed, fabricated, and tested for water treatment. The performance of the reactor was evaluated by testing phenoxy pesticides and chlorophenols, and it was optimized by studying the degradation of 2,4-dichlorophenoxyacetic acid. The effect of operational parameters including light intensity, distance between light emitting diode module and photocatalytic plate, recirculation flow rate, and external electron scavengers on the reactor’s performance were investigated. Furthermore, the performance of immobilized photocatalytic plate (anodized TiO2 nanotubes) was compared with slurry TiO2 and hollow glass microspheres coated with anatase TiO2. A power law relationship between the light intensity (2.2–17.3 mW/cm2) and first-order kinetics rate constants for 2,4-dichlorophenoxyacetic acid degradation was observed; a suitable circulation flow rate and the distance between light emitting diode module and photocatalytic plate was determined to achieve good degradation efficiency. Enhanced performance of the reactor was observed when H2O2 was introduced.