Synthesis and Characterization of Magnetic Nanocomposite Fe_3O_4@nSiO_2@mSiO_2 with Dual Shells Containing Non-porous Silica and Mesoporous Silica Structure

摘要

Magnetic nanocomposites of Fe_3O_4@nSiO_2@mSiO_2 were synthesized by a two-step template method. Firstly, Fe_3O_4 magnetic core encapsulated clusters of SiO_2 nanoparticles (Fe_3O_4@nSiO_2, non-porous SiO_2) was prepared by a spray drying method. Then the core-shell spheres of Fe_3O_4@nSiO_2 were coated further with an m-SiO_2 layer (mesoporous silica) by a sol-gel process using CTAB as a template. The resultant samples were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Nitrogen adsorption-desorption and Magnetic measurements. The acquired magnetic nanocomposites possess abundant mesopores, thus extends their potential application in biomedical and wastewater treatment due to their magnetic separation ability upon an external magnetic field.