Characterization of Superparamagnetic/Monodisperse PEG-Coated Magnetite Nanoparticles Sonochemically Prepared from the Hematite Ore for Cd(II) Removal from Aqueous Solutions

In this study, a novel sonochemically synthetic process of superparamagnetic and monodisperse magnetite nanoparticles from the Egyptian hematite ore has been done. Then the synthesized magnetite nanoparticles were subjected to surface modification through coating by polyethylene glycol to obtain stabilized and biocompatible magnetic nanoparticles (PEG-MN). The synthesized PEG-MN nanoparticles were characterized by the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XRF), vibrating sample magnetometer (VSM), infrared spectroscopy (FT-IR), adsorption of nitrogen (BET method), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. The results showed that the synthesized PEG-MN nanoparticles have an average crystalline size of 12 nm and 69.6% of iron oxide (Fe3O4) in the sample with a specific surface area of 219 m(2)/g. The magnetic hysteresis curve revealed that the synthesized PEG-MN nanoparticles exhibit a superparamagnetic behavior at room temperature with a saturation magnetization of 39.370 emu/g. While the morphology of the synthesized PEG-MN nanoparticles displayed a spherical shape and well-PEG coating of the magnetite particles as well as a perfect monodispersity of the particles. The reactivity of the PEG-MN nanoparticles was examined for adsorption of the cadmium ion Cd(II) from aqueous solutions. The maximum adsorption capacity of the PEG-MN nanoparticles was found to be 0.452 mg/g. The adsorption process is well fitted by the pseudo-second-order kinetic model, and the adsorption efficiency of Cd(II) was found to be 52% suggesting that the synthesized PEG-MN nanoparticles are an effective and promising tool for the removal of the selected metal.