Rutin precursor for the synthesis of superparamagnetic ZnFe2O4 nanoparticles: experimental and density functional theory

Superparamagnetic nanoparticles could be greatly used in biomedical fields like cancer hyperthermia, magnetic separation, and magnetic resonance imaging (MRI) enhancement. Furthermore, the biosynthetic method has been used to produce various nanostructures and nanoparticles due to the economical and eco-friendly route. In the present study, zinc ferrite (ZnFe2O4) nanoparticles were biosynthesized by applying rutin from Ruta graveolens L. extracted as a reducing and stabilizing agent. Furthermore, the chemical, thermal, and magnetic properties of the nanoparticles were evaluated by transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering method (DLS), ultraviolet–visible absorption spectroscopy (UV–Vis), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) spectroscopy, and thermal gravimetry analysis (TGA). The XRD and TEM results represented that the nearly spherical shape of zinc ferrite nanoparticles with an average diameter of 20–30 nm was successfully synthesized with a cubic structure. ZnFe2O4 nanoparticles exhibited superparamagnetic properties with the magnetization of 5.9 emu/g at 15 kOe that could be applied for medical devices or tissue imaging in the future. DFT calculations on the crystal structure, electronic, and magnetic properties of the ZnFe2O4 revealed that both simulated crystal structures and magnetic properties are in good agreement with experimental results. The band gap of ZnFe2O4 is 1.93 eV represented that is in good consistent with the optical band gap (2.11 eV). Furthermore, electronic results revealed strong interactions between O with Zn and Fe atoms. Both O–Zn and O–Fe bonds have a covalent character as well as the O–Zn bond strength is more than the O–Fe bond.