Preparation And Application Of Mesoporous Silica And Silica Composites

As an inorganic biology material, silica has been shown huge application prospect on catalysts loading and drug delivery, and so on. Especially, mesoporous silica materials have been obtained extensively attention on biology catalysis and biology medicine areas because of its characteristics of super specific surface area, large pore volume, available adjustment on morphologies and sizes. Hence, it takes higher demands for preparing of mesoporous silica. The synthesis of mesoporous silica is always under acidic or basic conditions. Furthermore, the process will takes long aged time to form mesoporous structure, and many procedures have harsh demand for temperature. These conditions limit the simple and fast fabrication of mesoporous silica materials. Here, we used relatively cheaper sodium silicate as Si resource and PI23 as surfactant, two kinds of mesoporous silica materials were prepared rapidly with the assistance of phosphate and sulfate, respectively. Moreover, we used sodium silicate and bismuth nitrate as raw materials, photocatalysts Bi2O3/SiO2 composites were prepared via sol-gel precess. The detailed results are summarized as follows:(1) At room tempreture, highly ordered mesoporous silica has been prepared under neutral condition with the assistance of phosphate uing sodium silicate as Si source and P123 as surfactant. This synthesis method is sample and rapid, the formation of mesoporous structure would be finished in several minutes. During this process, disodium hydrogen phosphate plays an important part as a flocculatingagent, bridging agent and pH adjuster. We study the influence of pH value and static time on regularity of the pore and the morphology, respectively. The results demonstrated that the obtained materials had highly ordered mesoporous structure and uniform pore diameter distribution when the pH value was 6.15. Based on the optical pH value, the morphology of mesoporous silica transferred to more uniform spherical particle. In addition, we studied the formation mechanism of ordered mesoporous silica.(2) At room temperature, highly ordered mesoporous silica was prepared rapidly under acidic condition with the assistance of sulfate using high modulus of sodium silicate as Si source and P123 as surfactant.Moreover, the mesoporous silica was functionalized with sulfonic acid groups by quantitive carbonization of benzyl alcohol impregnating in mesoporous silica and then sulfonation. We also researched the catalysis efficiency of vary loading weight acid catalysts on esterification reaction of oleic acid and methyl alcohol.(3) We used sodium silicate and bismuth nitrate as raw materials, photocatalysts Bi2O3/SiO2 composites were prepared via sol-gel precess. The results of characteristic revealed the photocatalysts prepared without hydrothermal treatment had smaller size particles and larger band gap energy. The photocatalysis experiment demonstrated the nanocomposite prepared without hydrothermal treatment exhibited higher photocatalytic efficiency for degradation of RhB and MO than that of product by hydrothermal treatment. And it also exhibit good absorb property for MB. The photocatalytic degradation mechanism of the composites was investigated.