Electro-oxidation of Ofloxacin antibiotic by dimensionally stable Ti/RuO₂ anode: Evaluation and mechanistic approach

Present study investigates the potential of Ti/RuO₂ electrode for degradation and mineralization of Ofloxacin (OFLX) antibiotic from synthetic wastewater by electro-oxidation (EO) method, not reported earlier. Effects of various EO parameters such as applied current (I), initial pH, initial OFLX concentration (C₀) and supporting electrolyte concentration on %OFLX removal efficiency and %TOC removal efficiency were systematically studied and reported. Decay kinetics of OFLX by varying C₀ and applied I were also studied. Additionally, mineralization current efficiency and specific energy consumption of OFLX mineralization were evaluated. Moreover, mode of oxidation method involved (direct and/or indirect oxidation) was also explored. Major OFLX transformation products during EO were identified using UPLC-Q-TOF-MS, and possible degradation reaction mechanism was proposed. Furthermore, operating cost analysis was performed to check the economic feasibility of the EO process. The optimum pH and current (I) were found to be ≈6.8 (natural pH of OFLX wastewater) and 1 A, respectively. Mineralization current efficiency decreased from 7.8% to 4.9% with increase in I value from 0.25 to 1 A. ≈80% of OFLX removal in 30 min of electrolysis and 46.3% TOC removal in 240 min of electrolysis at I = 1 A were observed. Pseudo-first-order kinetic model best fitted the experimental data showing R² value ≈ 0.99 for all the C_o and applied I studied.