Enhanced recalcitrant pollutant degradation using hydroxyl radicals generated using ozone and bioelectricity-driven cathodic hydrogen peroxide production: Bio-E-Peroxone process

Accelerated pollutant degradation was examined using a new combined chemical and bioelectrochemical system, called a Bio-E-Peroxone process, based on generating ⋅OH from H₂O₂ produced on the cathode of a microbial fuel cell (MFC) and using ozone-enriched air. To optimize H₂O₂ formation, different carbon materials were examined and the highest H₂O₂ rates were obtained using XC-72 carbon black cathode. In E-Peroxone tests using the XC-72 cathode, methylene blue (a model pollutant) degradation rates followed first-order kinetics, with a rate constant of 0.237 min⁻¹, 6 times higher than that obtained using only ozonation (0.032 min⁻¹), 15 times of electrolysis+O₂ system (0.015 min⁻¹) and 46 times greater than electrolysis (0.005 min⁻¹). In MFC tests when using the complete Bio-E-Peroxone system, the removal rate constant for methylene blue was 2.05 h⁻¹, compared to 1.86 h⁻¹ using only ozone and 0.41 h⁻¹ using only MFC. Adding ozone to the air in cathode also increased power production by 47% to 170 mW m⁻³. The results demonstrated that this Bio-E-Peroxone system could be a feasible method for both refractory compounds degradation and wastewater electricity generation.