Fe/Cu-γ-Al2O3 catalyst for pilot-scale internal circulation Fenton degradation of methyl orange: performance and mechanism.

The Fe/Cu-γ-Al2O3 catalyst was obtained via impregnation coupled with calcination and then applied to a pilot-scale heterogeneous Fenton process in an internal circulation fluidized bed reactor (IC-FBR) to remove methyl orange (MO). Under the optimal conditions (catalyst dosage 2.0 g/L, H2O2 30 mM, pH 3.3, and flow rate 0.8 m3/h), the decolorization efficiency of MO and COD removal efficiency reached 97.81% and 75.39%, respectively, and the degradation process followed the Behnajady-Modirshahla-Ghanbary (BMG) kinetic model. Hydroxyl radicals(•OH), superoxide radicals(•O2-), and singlet oxygen (1O2) were identified as the dominant reactive species, while the synergistic effects between Fe and Cu promoted the Fe3+/Fe2+ cycling, consequently boosting the catalytic performance. These findings offer valuable guidance for the practical implementation of IC-FBR Fenton technology in industrial wastewater treatment.