Honeycomb activated carbon/α-FeOOH catalyst: Construction of heterogeneous chemical and electrical Fenton for treating coking wastewater and dynamic practicality assessment

Abstract

Coking wastewater is an organic wastewater containing recalcitrant contaminants. If not treated properly, it poses a serious threat to public health and environment. In this study, a novel heterogeneous Fenton catalyst, honeycomb activated carbon (HAC)/α-FeOOH, was fabricated via an impregnation and calcination method, in which HAC served as a support matrix for immobilizing α-FeOOH. HAC/α-FeOOH exhibits notable process-intensification attributes, including broad pH adaptability (3−9), high efficiency, and practical applicability. In heterogeneous chemical Fenton, the removal rates of chemical oxygen demand (COD), NH₃-N, and color reached 89.3 %, 85 %, and 90 %, respectively. In the heterogeneous electrical Fenton (hetero-EF), the concentrations of COD and NH₃-N were both decreased to below the detection limit. The color removal efficiency reached 99 %. Kinetic analysis revealed that COD reduction followed first-order reaction kinetics. Both quenching experiments and electron paramagnetic resonance (EPR) spectra confirmed that the hydroxyl radicals (·OH) generated is the primary active substance for removing pollutants. Spectral analyses provided evidence of the effective degradation of heterocyclic and aromatic compounds. A miniaturized dynamic apparatus was constructed using HAC/α-FeOOH to mimic real industrial conditions. Over 48 h of continuous operation, the apparatus maintained excellent removal efficiency and stability, confirming the stable performance and practical application potential of HAC/α-FeOOH.