Enhancing hydrogen peroxide activation in heterogeneous Fenton reaction by codoping hydrochar with iron and Copper

The development of a bimetallic Fenton-type catalyst with desirable activity and reusability remains a major challenge for the practical degradation of organic pollutants. Herein, we focused on modifying almond shell hydrochar with a Fe/Cu bimetal (Fe/Cu-HC) to develop a catalyst capable of activating H₂O₂ for degrading MO. The bimetallic Fe/Cu-HC catalyst was synthesized through hydrothermal carbonization and pyrolysis and characterized using SEM, FTIR, BET analysis, and XRD to confirm the presence and uniform dispersion of Cu and Fe co-doped species on HC. The impact of various factors, such as the solution pH (X₁), organic pollutant concentration (X₂) and catalyst mass (X₃), on dye degradation efficiency via heterogeneous Fenton oxidation, was examined using the BBD model coupled with Surface response methodology (RSM). The Fe/Cu-HC catalyst showed superior performance in degrading MO dye compared to single-metal catalysts (Cu-HC, Fe-HC), due to the synergistic interaction between Fe and Cu species. To demonstrate the heterogeneous Fenton catalytic performance of the synthesized FeCu/HC, the results showed that 98.97 % of methyl orange was eliminated under optimal conditions: 100 mg. l^-1 of methyl orange, a duration of 1 h, a catalyst mass of 1.65 g. l^-1, a pH of 6, and a concentration of 4 mM H₂O₂. In addition, the Fe/Cu-HC catalyst showed excellent stability over multiple cycles, with minimal metal leaching. These results indicate that Fe/Cu-HC is a promising catalyst for the degradation of methyl orange and pave the way for the development of other cost-effective and efficient bimetallic catalysts for environmental remediation.