Synthesis, Characterization And Application Of Functionalized Mesoporous Silica

Mesoporous silica nanoparticles have received explosive interests due to their unique features, such as high surface area, highly ordered pore structure, adjustable pore size, uniform open pores and good biocompatibility, and they show great potentiality in sensor, catalysis, adsorption and separation, bioimaging, drug delivery and so on. After twenty years of exploration, it is still significant to explore functions mediated synthesis of mesoporous silica and expand their application with the deepening of the various research areas. This thesis mainly focuses on two aspects: investigate the synthesis of new functional mesoporous silica materials; explore the applications of the functional mesoporous silica materials.Firstly, prepare different pore sizes of SBA-15mesoporous silica by selecting tetraethoxysilane as silicon source, hexadecyl trimethyl ammonium bromide as surfactant, and then modify mesoporous silica by selecting appropriate indicators and silane coupling agent. Successful modification of mesoporous silica is proven by X-ray powder diffraction, transmission electron microscopy, infrared, nitrogen adsorption desorption, thermogravimetric analysis.Secondly, the modified material realizes the detection and removal of mercury ion. Moreover, it shows high selectivity, and the limit of detection reaches0.5ppb (a significant standard by U.S. Environmental Protection Agency for the safe drinking water). The modified mesoporous silica has good adsorption properties for mercury ion, and the adsorption efficiency reaches96%with a adsorption capacity of192mg/g when the initial concentrations of Hg2+and modified mesoporous silica are1.0mM and1.0mg/g, respectively.Thirdly, a very facile and in-situ approach for the synthesis of modified mesoporous silica was developed through a mild hydrothermal reaction between diamino functionalized SBA-15and citric acid. It showed a very good fluorescence properties. The modified material was successfully obtained by the characterizations of X-ray powder diffraction, transmission electron microscopy, infrared, nitrogen adsorption desorption, thermogravimetric analysis.Finally, the prepared fluorescent mesoporous silica was used in the detection and adsorption of mercury ions, as well as in vitro cell imaging. The study revealed that the material can be employed as a highly selective and sensitive probe and potential adsorbent for Hg2+. MTT assay showed that fluorescent mesoporous silica had a lower cytotoxicity. Breast cancer cells MCF-7cell imaging showed that fluorescent mesoporous silica was successfully engulfed MCF-7cells, with a strong blue fluorescence, indicating the potentiality of flurescent mesoporous silica in drug delivery and tracing. The research lays a good foundation for the design of complex multifunctional nanostructures, and will promote the application of fluorescent mesoporous silica nanoparticles mediated in many fields.