A Feasible Mechanochemical Ball Milling Method for Preparing Persulfate Activator for Tetracycline Degradation
Abstract
The use of activated persulfate to degrade antibiotics has been proven to be an effective technique. However, this technology requires the preparation of many nanoscale persulfate activators to adapt to engineering applications, which is still a challenge at present. In addressing the issue, this work prepared a nanoscale composite of pyrite@activated carbon (named FeS2@AC) by mechanochemical ball milling. The composite has been shown to effectively activate persulfate, generating sulfate radicals (SO4-•) and hydroxyl radicals (OH•). The optimal reaction conditions were determined through orthogonal experiments, range analysis, and variance analysis. At initial concentrations of 50 mg/L and 100 mg/L, the degradation rates of tetracycline hydrochloride by FeS2@AC reached 87.28% and 85.62%, respectively. Combining experimental validation and density functional theory (DFT) calculations, Fe2+ serves as the primary catalytic site, while S- species facilitate rapid Fe3+/Fe2+ cycling, enhancing radical generation and catalytic durability. Notably, this one-step ball milling approach offers a cost-effective, scalable, and environmentally benign alternative to traditional nanomaterial synthesis methods. The study further elucidated degradation pathways and intermediate toxicity, providing critical insights for practical implementation. These findings present a transformative framework for engineering high-activity nanocatalysts to combat antibiotic pollution in wastewater treatment.