Degradation of the anti-inflammatory drug ibuprofen by electro-peroxone process

Electro-peroxone (E-peroxone) treatment of the anti-inflammatory drug ibuprofen aqueous solution was investigated in this study. The E-peroxone process combined conventional zonation with electrolysis processes, and used a carbon-polytetrafluorethylene cathode to electrochemically generate H2O2 from O-2 in the sparged ozone generator effluent (O-2 and O-3 mixture). The in-situ generated H2O2 then reacted with the sparged O-3 to produce aqueous center dot OH, which can in turn oxidize pollutants effectively in the bulk solution. The E-peroxone process overcomes several intrinsic limitations of conventional zonation and electrolysis processes for pollutant degradation such as the selective oxidation with O-3 and mass transfer limitations of pollutants to the electrodes, and thus significantly enhanced both ibuprofen degradation and total organic carbon (TOC) mineralization. Results show that ibuprofen could be completely degraded much more rapidly in the E-peroxone process (e.g., 5-15 min under all tested reaction conditions) than in zonation (>= 30 min) and electrolysis (several hours) processes. In addition, thanks to the powerful and non-selective oxidation capacity of center dot OH, toxic intermediates formed during ibuprofen degradation could be completely mineralized in the E-peroxone process. The E-peroxone effluent (2 h) thus exhibited much lower toxicity (5% inhibition of bioluminescence of Vibrio fisheri) than the ozonation and electrolysis effluents (22% and 88% inhibition, respectively). The results of this study indicate that the E-peroxone process may provide a promising technology for pharmaceutical wastewater treatment. (C) 2014 Elsevier Ltd. All rights reserved.