Synthesis And Morphology Control Of Magnetic Mesoporous Materials Via Self-assembly

In recent years, magnetic mesoporous silicas (MMS) have attracted lots of attention all over the world due to its potential applications. This kind of novel material has adopted the advantages of porous structure and magnetic properties. As is well known, mesoporous silica (MS) has large surface area, uniform pore structure, chemical stability and optical transparency. When MS materials possess the magnetic property, it provides a possibility for them to be controllably moved and placed via a magnetic field. It could introduce new applications to the porous material. On the other hand, MS has various types of mesophases, which is related to the shapes of micelles and the interaction between surfactant micelles and silicate species. Changing the morphology of MS has a significant influence on their use. A lot of methods have been made to tune the morphology in the form of fibers, spheres, film, hollow tubes, rods and so on. This thesis launched a series of studies which focused on the synthesis and application of morphology control of MMS. The main results are as follows:1. A facile method, which was based on the cationic surfactant self-assembly and oxidation, was designed to fabricate MMS. Three types of metalorganic amphiphiles with a terminal ferrocene moiety were synthesized and used as structure-directing agents and iron source to prepare MMS. Among all the surfactants, FcC11PyBr exhibited the best ability to produce mesopores with tetraethoxysilane at a suitable molar ratio. After the oxidation reaction at573K, the MMS material showed an obvious magnetic property, with a large surface area and pore volume. The MMS was found have a good absorptivity and used as magnetic adsorbent to remove some dye pollutants in water.2. Using FcC11PyBr as the structure-directing agent, it was easy to control the morphology of MMS by adjusting the solvent and its ratio. It can be controllable to fabricate diverse morphologies of MS:powder, sphere, rodlike powder and film. After the oxidation reaction at573K, these various morphologies of MMSs possess a magnetic property, with a large surface area and pore volume. They were characterized by X-ray diffraction, N2adsorption-desorption isotherms, SEM, TEM and vibration magnetometry.