Degradation of a Toxic Pollutant (Pyridine) in a Flat-Bed Reactor Using Ultraviolet Light: Comparison of Two Catalysts (ZnO-Au and TiO₂-Au)

In this research, a falling film reactor with UV light lamps as a photon emission source was designed and constructed for the degradation of the organic pollutant pyridine. Doping of the catalysts, zinc oxide with gold (ZnO/Au), and titanium dioxide with gold (TiO₂/Au) were performed by photodeposition technique. Subsequently, the doped photocatalysts were supported on ceramic clay sheets at 550 °C. The characterization of the photocatalysts was carried out by Scanning Electron Microscopy (SEM) and UV-vis DR spectroscopy. The following operating conditions were used for pyridine degradation: pH (acidic pH =5.5, natural pH =7.2 and basic pH =8.5) and hydraulic residence time (HRT) (0.2 L/min, 0.5 L/min and 1 L/min). Degradation monitoring was performed by UV-vis Spectroscopy, Total Organic Carbon (TOC), and High-Performance Liquid Chromatography (HPLC). A maximum pyridine removal of 97.64% was obtained using the ZnO/Ag photocatalyst, demonstrating the viability of this photocatalytic system for the degradation of organic pollutants such as pyridine.