Sustainable synthesis of ZnO and FexOy nanoparticles and their nanocomposite ZnFe2O4: Comprehensive characterization and applications in antioxidant activity and antibiotics degradation efficiency

Abstract

This study focuses on developing and evaluating eco-friendly nanoparticles, specifically Fe x O y NPs , ZnO NPs , and a ZnFe 2 O 4 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 Fe x O y NPs , 22.1 nm for ZnO NPs , and 10.9 nm for ZnFe 2 O 4 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 Fe x O y NPs, ZnO NPs , and ZnFe 2 O 4 NC, respectively. Morphological analysis via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that Fe x O y NPs have cubic, hexagonal, and tetragonal forms, ZnO NPs are hexagonal nanorods, and ZnFe 2 O 4 NC has a hexagonal-faced cubic structure. Antioxidant activity, assessed through the DPPH assay, revealed that ZnFe 2 O 4 NC had the highest potency. Additionally, under sunlight irradiation, ZnFe 2 O 4 NC demonstrated superior degradation of the antibiotic cephalexin (96 % within 30 min) compared to Fe x O y NPs (58.2 %) and ZnO NPs (52 %), with respective kinetic rate constants of 0.109 min −1 , 0.029 min −1 , and 0.025 min −1 . These results highlight the nanoparticles’ potential for environmental and biomedical applications.