Facile and Economic Method for the Preparation of Core-Shell Magnetic Mesoporous Silica

In this work core-shell structure Fe3O4@SiO2@meso-SiO2 microsphere has been successfully prepared. An inorganic magnetic core has been coated with multi-shell structure, dense nonporous silica as an inner layer and mesoporous silica as an outer layer. The dense silica shell can enhance the stability and minimize the negative effect of acidic conditions on the inner core and the porous outer shell can provide high surface area and enhance the loading of a functionalized group. Cetyltrimethylammonium bromide (CTAB) has been used as a pore-forming agent and a modified methodology was adopted to improve the extraction condition of this kind of surfactant. The as-prepared microspheres were characterized by Field Emission Scanning Electron Microscope (FESEM), X-Ray Diffraction (XRD), Fourier Transform InfraRed (FT-IR) spectroscopy, Vibration Sample Magnetometer (VSM), N2 adsorption-desorption, and Particle Size Analyzer (PSA). The resulted materials possessing uniform core-shell structure, and well preserved structural stability. Additionally, they can be collected readily by using an external magnetic field. The prepared material has considerable potential applications in various fields including catalysis, drug delivery, and water treatment.