Photocatalytic oxidation of aqueous naproxen with a horizontally placed solar CPC slurry reactor

A solar photocatalytic reactor, that includes a horizontal compound parabolic collector (CPC) with a unitary geometrical concentration ratio, was designed, built and tested. The reactor was used for the photocatalytic oxidation of aqueous naproxen (NPX) with solar UV irradiance. NPX (C-o = 10 mg/L) and its intermediate products were monitored by UV-Vis spectrophotometry after filtering the samples. This target molecule was effectively removed when solar irradiance, Evonik P25 TiO2 and persulfate were used together. No intermediate products remained at important concentrations at the end of the reactions. The reaction kinetics fit partially to a pseudo-first-order Langmuir-Hinshelwood kinetic model. NPX and its intermediate compounds were removed with global efficiencies of up to 99%. These results indicate that the TiO2-based photocatalytic reactor, with a good optical design for the CPC collectors, can be effective in detoxifying polluted waters.