Degradation of cefadroxil by photoelectrocatalytic ozonation under visible-light irradiation and single processes

Here, we investigate the degradation of 20 mg L^-1 Cefadroxil (CFX) in water using photoelectrocatalytic ozonation (PECO), and compared against its individual processes. A carbon nitrogen-codoped titanium dioxide (CN-TiO₂) anode is synthesized using ethylene glycol and ethylenediamine as carbon and nitrogen source, respectively. The X-ray diffraction (XRD) and Scanning Electronic Microscopy (SEM) analysis conducted to this material indicate a crystalline phase anatase with irregular morphology formed on the electrode surface; while the diffuse reflectance spectroscopy (DRS) shows a shift in the photoanode absorbance towards the visible region, unlike undoped TiO₂ structure. This behavior results from the inclusion of Carbon and Nitrogen species on the CN-TiO₂ electrode in weight percentages of 14.5 and 1.61 wt%, respectively, according to Energy Dispersive Spectroscopy (EDS) analysis. The Cefadroxil (CFX) abatement is monitored UV–Vis spectroscopy, high-performance liquid chromatography (HPLC), and total organic carbon (TOC). All techniques reveal that the highest CFX removal occurs with PECO (Photoelectrocatalytic Ozonation) process, decreasing TOC by 57.6% (96% degradation by HPLC) after 90 min of treatment. The main by-products formed from oxidation with the PECO, PCO (Photocatalytic Ozonation) and O₃ (Ozonation) systems were acid species presumably corresponding to short chain carboxylic acids. Finally, the germination of lettuce sativa is carried out in water contaminated with the drug, and compared with water treated by PECO and PCO processes, showing that PECO process improves germination by 23.5% on the contaminated sample and 7.4% on the sample treated with PCO. These findings confirm that synergism of oxidation techniques could be a tractable way to resolve the problems related to recalcitrant compounds contained in wastewater.