Sustainable ZnO nanoparticles synthesized from black elderberry fruit extract for efficient photocatalytic degradation of norfloxacin drug
摘要
The extensive use of antibiotics poses significant environmental and health risks due to the contamination of aquatic ecosystems with persistent pharmaceutical residues. This study explores the photocatalytic degradation of norfloxacin, a commonly used fluoroquinolone antibiotic, employing green-synthesized zinc oxide nanoparticles (ZnO NPs) derived from Sambucus nigra (black elderberry) fruit extract. The novelty of this work lies in utilizing S. nigra as a natural reducing and stabilizing agent, offering an eco-friendly, low-cost synthesis route and focusing on pharmaceutical pollutants instead of conventional dyes. The influence of calcination temperature (500–700 °C) on the structural and optical characteristics of ZnO NPs was thoroughly examined. X-ray diffraction revealed a polycrystalline wurtzite structure with increasing crystallite size at higher temperatures, corroborated by FESEM images showing particle sizes between 20 and 90 nm (average ≈ 58 nm). UV–Vis analysis indicated a slight bandgap narrowing from 2.67 to 2.60 eV, enhancing photocatalytic efficiency. Degradation performance was strongly dependent on catalyst dosage, pH, and calcination temperature. Under optimal conditions (0.5 mg/mL ZnO NPs, pH 9), 89.8% degradation was achieved within 120 min, dominated by hydroxyl radical activity and following pseudo-first-order kinetics, with ZnO NPs calcinated at 700 °C exhibiting the highest rate constants. Utilizing natural sunlight instead of artificial UV light provides a sustainable, energy-efficient, and scalable approach, demonstrating the practical potential of green-synthesized ZnO NPs for pharmaceutical wastewater remediation.