Ofloxacin degradation in chloride-containing medium by photo-assisted sonoelectrochemical process using a mixed metal oxide anode.

A photo-assisted sonoelectrochemical (UV/US/EC) hybrid process using a mixed metal oxide (MMO) (e.g., Ti/Ru 0.3 Ti 0.7 O 2) electrode was evaluated with the aim of investigating the degradation and mineralization of ofloxacin (OFL) in a chloride-containing medium. Under optimized condition (30 mA/cm², 0.05 mol/L NaCl, 10 mL/min, and natural pH), the OFL concentration decayed to 0 in 5 min and, after only 60 min of treatment, ~60% TOC was removed. The comparison of different combinations of UV, US, and EC techniques showed that the UV/US/EC and UV/EC techniques were the most advantageous, due to the production of highly reactive radicals through photolysis of electrochemically generated active chlorine species. A significant reduction in OFL was only achieved in the presence of NaCl, compared to Na 2 SO 4 as supporting electrolyte, demonstrating that DSA® electrodes have high electrocatalytic activity for chlorine evolution. Under real conditions, the percentage of OFL removal from the river water sample was 97% after 10 min of treatment. Phytotoxicity tests indicated that it is possible to reduce the toxicity of the solution using NaCl as supporting electrolyte. In addition, a mineralization pathway for OFL was proposed for the process in question. [Display omitted] • Complete OFL degradation was reached within 5 min of UV/US/EC process. • 60% of TOC was removed after 60 min of treatment. • Positive synergistic effects were obtained for the UV/US/EC and UV/EC techniques. • The hybrid UV/US/EC process showed low energy consumption (55.48 kWh/m³, $0.99/m³). • The toxicity of the solution in chloride-containing medium was drastically reduced. [ABSTRACT FROM AUTHOR]