Performance and Mechanism of Fe3O4 Loaded Biochar Activating Persulfate to Degrade Acid Orange 7

Abstract

Azo dye wastewater is a common type of organic wastewater that often presents a significant challenge due to its gloomy color, high toxicity, and resistance to degradation. The discharge of such wastewater directly into natural water bodies can pose a severe threat to both ecological security and human health. Traditional biological treatment methods are often ineffective in treating industrial pollutants, but advanced oxidation technologies, such as persulfate (PS), offer unique advantages due to their strong oxidation ability and short reaction times. This study investigates the use of modified biochar (BC) material and catalyzed persulfate advanced oxidation technology to adsorb and separate acid orange 7 (AO7), a common industrial pollutant, from water and further oxidize and degrade it. Wood chips were used as biological templates to create an efficient, eco-friendly, and reusable adsorbent and catalytic material. In this paper, the adsorption effect of Fe3O4@BC on AO7 in water was compared, the adsorption kinetics and isotherm of Fe3O4@BC on different pollutants were studied, and the possible adsorption mechanism was proposed based on the relevant characterization. Adsorption kinetics describes the rate and quality of adsorption by studying the adsorption capacity in the adsorption process. Furthermore, the activated PS system was used to explore the degradation of AO7 at room temperature. First, the catalytic performance of Fe3O4@BC was evaluated by examining the amounts of PS and Fe3O4@BC, the initial pH, the ionic strength, and the reusability of Fe3O4@BC. Then, a possible degradation mechanism was proposed through electron paramagnetic resonance (EPR), free radical quenching experiment, and density functional theory (DFT) analysis. The results of this study suggest that modified biochar material and catalyzed persulfate advanced oxidation technology offer an effective and eco-friendly method for treating AO7 in wastewater.