Anodized graphite felt as an efficient cathode for in-situ hydrogen peroxide production and Electro-Fenton degradation of rhodamine B

This work investigated that the graphite felt anodized by NaOH, NH4HCO3, or H2SO4 aqueous, and then as the cathode materials for in-situ hydrogen peroxide (H2O2) production and its employed for rhodamine B (RhB) degradation via Electro-Fenton (EF) process. At-0.60 V (vs. SCE), after 120 min electrolysis, the H2O2 yield by graphite felt which anodized by 0.2 M H2SO4 achieved up 110.5 mg L-1 in 0.05 M Na2SO4 electrolyte. Compared with the raw graphite felt used for cathode, the H2O2 yield increased by 15.85 times under the same conditions. The results of Raman spectroscopy demonstrated that graphite felt anodized by H2SO4 solution can be achieved the highest defect degree. For the degradation of RhB, the cathode which anodized by H2SO4 solution has the highest removal rate. For the degradation rate of RhB, the effect of applied current density, Fe2+ ions concen-tration, pH value were investigated. In addition, suggested that the efficient Fe3+ reduction reaction on the cathode surface was an important reason of the high efficiency of RhB degradation. 5-times continuous runs indicated that the modified cathode has remarkable stability and reusability during the EF process.

Automated summary

This study found that graphite felt anodized by H2SO4 solution exhibited the highest H2O2 yield and RhB removal rate in the EF process. The effects of current density, Fe2+ ion concentration, and pH value on the degradation rate of RhB were investigated under different conditions. The efficient Fe3+ reduction reaction on the cathode surface was identified as a key factor for the high efficiency of RhB degradation. Additionally, the modified cathode showed remarkable stability and reusability during 5 consecutive runs in the EF process.