Preparation and Surface Modification of Magnetic Fe3O4 Nanoparticles

In this work, the coprecipitation method was used to prepare the magnetic Fe 3 O 4 nanoparticles which were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The particle size and saturation magnetization of Fe 3 O 4 nanoparticles were significant effected by temperature and the precipitant's precipitation time. Under the reaction temperature of 40 °C and the dropping time of 10 h, the size and the saturation magnetization of magnetic Fe 3 O 4 nanoparticles were 9.4 nm and 37.5 emu/g, severally. Besides, the magnetic Fe 3 O 4 nanoparticles were also resoundingly modified with silica (SiO 2 ), chitosan (CS) and sodium alginate (SA). And the hydrodynamic diameters of the Fe 3 O 4 /CS micro-composites and Fe 3 O 4 /SA micro-composites in aqueous solution were 1.16 μ m and 2.11 μ m, respectively.