Preparation of Fe3O4/C Composite Material from Red Mud for the Degradation of Acid Orange 7

This study presents a novel Fe3O4/C composite material synthesized from red mud through a process of magnetic roasting and separation. The research explores the impact of Fe3O4/C dosages, sodium persulfate (PS) concentrations, and initial solution pH on the chemical oxygen demand (COD) removal efficiency using Acid Orange 7 as a model pollutant. Optimal conditions were identified as 3 g/L Fe3O4/C, 20 mM PS, and an initial pH of 2, achieving a 94.11% COD removal efficiency within 30 min. X-ray diffraction and photoelectron spectroscopy analyses confirmed that the magnetization roasting process effectively transformed red mud’s ferric oxide (Fe2O3) into magnetite (Fe3O4). Concurrently, Fe3O4 interacted with residual carbon to form the Fe3O4/C composite. This composite demonstrated superior catalytic performance, along with excellent recyclability and reusability.