Carbon sponge as a new cathode material for the electro-Fenton process: Comparison with carbon felt cathode and application to degradation of synthetic dye basic blue 3 in aqueous medium

A novel cathode material, carbon sponge (CS), was investigated for treating wastewater containing the basic blue 3 (BB3) dye by electrochemical advanced oxidation processes, electro-Fenton. The efficiency of the CS electrode was comparatively discussed with carbon felt (CF) electrode for degradation of BB3. The amount of electrogenerated H2O2 by using CS electrode was three times higher than that of CF electrode. The effect of some operational parameters such as applied current value, type of supporting electrolyte, O2 flow rate, pH and temperature on the generation of H2O2 was investigated. The optimal current value for the H2O2 production was 100 mA (5.6 mA cm−2). The applied current, temperature and O2 flow rate have a significant effect on the amount of electrogenerated H2O2, whereas supporting electrolyte and pH of the solution have a slight affect. The degradation and mineralization of BB3 were followed by using HPLC and TOC analysis, respectively. The degradation and mineralization of BB3 using CS was faster than that of CF. At the end of eight hours electrolysis under the same conditions, 91.6% and 50.8% of the initial TOC of the system was removed by using CS and CF electrodes, respectively. The mineralization current efficiency (MCE) of CS electrode was four times higher than that of CF electrode. The results showed that the CS electrode provides an alternative cathode material for future designing of water treatment system in the electro-Fenton process.