Degradation of tetracycline in water using hydrogen peroxide activated by soybean residue-derived magnetic biochar

Tetracyclines (TCs) are the second most commonly used antibiotics worldwide, utilized in medical treatments and animal husbandry. Although effective against various infectious diseases, TC residues persist in the environment and contribute to the emergence of antibiotic-resistant pathogens, posing significant risks to human health. This study employed the heterogeneous Fenton process to degrade TC using soybean residue-derived magnetic biochar (Fe-SoyB) as the catalyst. The Fe-SoyB sample was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and superconducting quantum interference device (SQUID) techniques. The effects of key parameters, including pH, H₂O₂ concentration, catalyst dosage, and initial TC concentration, on TC degradation were investigated. The results indicated that the TC removal efficiency decreased with increasing initial TC concentration, while it was improved with higher H₂O₂ concentrations and greater catalyst dosages. The optimal conditions for the Fenton-like process were determined: a pH of 3, a H₂O₂ concentration of 245 mmol/L, an initial TC concentration of 800 mg/L, and a catalyst dosage of 0.75 g/L, achieving a removal efficiency of 90.0% after 150 min. Additionally, the TC removal efficiency of the Fe-SoyB system varied significantly across different water matrices, with 87.1% for deionized water, 78.5% for tap water, and 72.5% for river water. The catalyst demonstrated notable stability, maintaining a TC removal efficiency of 79.7% after three cycles of use. Overall, Fe-SoyB shows promise as a cost-effective catalyst for the elimination of organic pollutants in aqueous solutions.