Activated carbon loaded with Fe@Fe2O3 and CeO2 as a novel composite catalyst for heterogeneous electro-Fenton process

A novel heterogeneous electro-Fenton (HEF) composite catalyst based on activated carbon (AC) as the support material was prepared with the inclusion of Fe@Fe2O3 for its HEF catalytic activity and cerium oxide (CeO2) for its redox properties. The effect of different Fe/Ce molar ratios on the activity of the prepared catalysts was investigated. XRD, BET, FTIR, SEM, and EDS techniques were used to characterize the prepared catalysts. The catalyst activity was examined by its ability to degrade 50 mg/L of methylene blue (MB) at 20 mA/cm² and pH 3 within 150 min. A higher removal rate of 91% was achieved when AC+Fe/Ce (2:1) was used as a HEF catalyst. The results confirmed the synergy between Fe and Ce at a Fe/Ce molar ratio of 2:1. This improved catalyst was used to remove chemical oxygen demand (COD) from petroleum refinery wastewater. The optimum conditions were a current density of 10 mA/cm², pH of 3, and a catalyst dosage of 1 g/L, achieving a COD removal rate of 83.4%, with an energy consumption of 9.22 kWh/kg COD. Reusability testing confirmed the good catalytic activity of AC+Fe/Ce (2:1) catalyst after five cycles. Furthermore, the COD degradation over time was found to follow pseudo-first-order kinetics. These findings demonstrate that the prepared AC+Fe/Ce (2:1) catalyst is a highly efficient and energy-effective material for degrading organic pollutants in wastewater.