Visible-Light-Driven S-Scheme MgFe-LDH/BiVO4/Activated Carbon Composite for the Degradation of Tetracycline Antibiotic.

The widespread contamination of water bodies by antibiotics poses a significant threat to global ecosystems. In this study, a novel MgFe layered double hydroxide (LDH)-BiVO4/activated carbon (AC) composite was synthesized and utilized for the photocatalytic degradation of tetracycline (TC) under visible light irradiation. The composite achieved a 92% degradation efficiency (20 mg/L TC, 0.2 g/L dosage, pH 7) within 120 min, significantly outperforming pure MgFe and BiVO4. This enhanced performance is attributed to the formation of an S-scheme heterostructure, which facilitates the efficient separation of photogenerated charge carriers while maintaining a high redox potential. Scavenger experiments identified hydroxyl radicals as the primary reactive species during the degradation process. In addition, toxicity assessment using Protox-3 and ADMETlab 3.0 confirmed the progressive detoxification of TC during the degradation. The composite demonstrated excellent stability and reusability over six consecutive cycles. Furthermore, the composite shows practical applicability using real wastewater samples by retaining an 81% degradation efficiency.