Metal Doping Porous Silicon Aluminum Oxide Composite Materials Preparaed By Sol-gel Method

Mesoporous SiO2 has some unique structural characteristics such as extremely high surface area,narrow poer size distribution and large adjustable pore sizes (2-50nm), which have made such materials become the researching focus of porus materials. They could have potential application in various fields especially in adsorption and separation, ion exchange, catalysis, molecular host, optoelectronic, photonic devices, sensing, drug delivery and so on.In this paper, mesoporous silica and its metallic oxide doped composite materials were synthesized by sol-gel and hydrothermal methods, using polyethylene glycol (PEG) as template. The influences of reaction condition, such as molecular weight and addation ratio of PEG, doping metal ions, calcination temperature, on porous structure were investigated in details. The application in adsorption of organic dyes in wastewater was studied. The thesis includes the following sections:First, sol-gel method was employed to synthesize mesoporous silica and its metallic oxide doped composites using nonionic surfactants PEG as template. The influence of PEG molecular length and weight, metallic doping amount, calcination temperature on the mesoporous structure of composites was investigated. The results showed that mesoporous structure could be regulated by the molecular weight and concentrations of PEG and length of chains. Generally, molecular weight had few influence on mesoporous structure, however, SABET and Vtot increased with the increment of PEG mass. The pore volume and specific surface of doped composites decreased owing to some metallic oxide occupied pore channel. Chemical bonds of Si-O-M were formed which enhanced the thermal and hydrothermal stability of composites. In addition, influence of calcination temperature was also studied, the organtic could't be get ride of completely at low temperature and porous framework of silicon collapsed at high temperature. The results showed that the optimum temperature was 550℃.Second, CuO/SiO2 composite was prepared by sol-gel method, the samples were characterized by XRD, N2 isothermal adsorption-desorption method, fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HRTEM) and so on. The results showed that: the introduction of CuO didn't change the framework of SiO2; the bonds of Si-O-M were formed; the specific surface of material declined as a result of small particles of CuO crystal occupying pore channel partially.Third, CuO/SiO2 composites were synthesized by sol-gel-hydrothermal method. The adsorption of methylene blue (MB) was studied. The results showed that CuO/SiO2 mesoporous composite had good absorbability of MB. The maximum removal rate reached 97.17% in the condition that the pH value was 9,0.015g sorbent (Cs-600-6-15-NaOH-11-12h-140) was added.As a whole, the experimental resultes showed that the mesoprous SiO2 and metal ions doped mesoporous SiO2 composite could prepared by sol-gel method and hydrothermal route using PEG as template. The mesoporous structure could be regulated by the molecular weight and concentrations of PEG and length of chains. Inorganic metal oxide could be introduced into the framework of with the formation of Si-O-M bonds which endow mesoporous SiO2 composite with new physical and chemical properties. The multifunctional mesoporous composites could have a wide application at the fileds of adsorption catalysis.