Effective degradation of methylene blue by a novel electrochemically driven process

A new electrochemically driven process (E-peroxone) was developed to treat methylene blue (MB) wastewater. During the E-peroxone process, ozone generator effluent (O2 and O3 gas mixture) is continuously sparged into a reactor that has a carbon-polytetrafluorethylene (carbon-PTFE) cathode, which can electrochemically convert the sparged O2 to H2O2 effectively. The in situ generated H2O2 then reacts with the sparged O3 to produce hydroxyl radicals (OH), which are a much stronger oxidant than O3. Thus, by utilizing the sparged O2 that has little value in ozonation processes to produce H2O2 in situ, the E-peroxone process can achieve the synergy of O3 and H2O2 (peroxone) on pollutant degradation. The E-peroxone process therefore mineralized MB much more effectively than ozonation. The total organic carbon removal was 93 and 22% after 2 h of the E-peroxone and ozonation treatment, respectively. The E-peroxone process may thus offer a simple and effective method to degrade ozone-refractory organic pollutants in wastewater.

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► A new electrochemically driven process (electro-peroxone) was developed.
► H2O2 is electro-generated in situ from O2 in sparged O2 and O3 gas mixture.
► The E-peroxone process can achieve synergy of H2O2 and O3 for organic degradation.
► The E-peroxone process is an effective method for degrading refractory organics.