Synthesis and Characterization of Magnetic Nanocomposite Fe₃O₄@nSiO₂@mSiO₂with Dual Shells Containing Non-Porous Silica and Mesoporous Silica Structure

Abstract

Magnetic nanocomposites of Fe 3 O 4 @nSiO 2 @mSiO 2 were synthesized by a two-step template method. Firstly, Fe 3 O 4 magnetic core encapsulated clusters of SiO 2 nanoparticles (Fe 3 O 4 @nSiO 2 , non-porous SiO 2 ) was prepared by a spray drying method. Then the core-shell spheres of Fe 3 O 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.