Sustainable synthesis of ZnO and FeO nanoparticles and their nanocomposite ZnFeO: Comprehensive characterization and applications in antioxidant activity and antibiotics degradation efficiency.

This study focuses on developing and evaluating eco-friendly nanoparticles, specifically FeO NPs, ZnO NPs, and a ZnFeO nanocomposite (NC), for potential applications in environmental remediation and biomedicine. The nanoparticles were synthesized and characterized using X-ray diffraction (XRD), which revealed their crystalline structures with sizes of 20.3 nm for FeO NPs, 22.1 nm for ZnO NPs, and 10.9 nm for ZnFeO NC. Fourier-transform infrared (FTIR) spectroscopy identified functional groups, while UV-visible spectroscopy determined band gap energies of 2.35 eV, 3.38 eV, and 2.68 eV for FeO NPs, ZnO NPs, and ZnFeO NC, respectively. Morphological analysis via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that FeO NPs have cubic, hexagonal, and tetragonal forms, ZnO NPs are hexagonal nanorods, and ZnFeO NC has a hexagonal-faced cubic structure. Antioxidant activity, assessed through the DPPH assay, revealed that ZnFeO NC had the highest potency. Additionally, under sunlight irradiation, ZnFeO NC demonstrated superior degradation of the antibiotic cephalexin (96 % within 30 min) compared to FeO NPs (58.2 %) and ZnO NPs (52 %), with respective kinetic rate constants of 0.109 min, 0.029 min, and 0.025 min. These results highlight the nanoparticles' potential for environmental and biomedical applications.