Preparation And Application Of Magnetic Mesoporous Silica Composites

The large amount of industrial waste water makes the environment more and more pressure.Among them,the heavy metal wastewater and dye wastewater in metallurgical industry are seriously polluted.Because of the traditio nal physical,chemical and biological methods of wastewater treatment,there are two problems,such as expensive,double pollution and difficult to meet the national emission standards.Therefore,it is urgent to find new methods for wastewater treatment.In recent years,mesoporous silica as adsorbent or photocatalyst functional materials have been widely used in heavy metal adsorption and photocatalysis.However,the efficient use of mesoporous materials,well-developed pore structures and photocatalysts（TiO₂）still plague people.Therefore,the research and development of recyclable and high efficiency mesoporous silica adsorbent or photocatalyst is a hot research topic.The Fe₃O₄ microspheres prepared by solvothermal method,using magnetic m esoporous silica core-shell structure was prepared by St?ber modified.Scanning e lectron microscopy（SEM）and transmission electron microscopy（TEM）were use d to characterize the morphology of the material.It was found that the amount of TEOS could be changed,and the mesoporous silica shell with different sizes could be obtained.The best preparation conditions for synthesis of magnetic mes oporous silica were: 0.15 g,Fe₃O₄,0.45 mL,TEOS（TEOS）,alcohol water ratio（V:V）,3:4,0.6g sixteen alkyl three,ammonium bromide（CTAB）,reaction time 12 h.At this time,the prepared magnetic mesoporous silica has good dispersion a nd good core-shell structure,and the magnetic saturation intensity is between 30.97emu·g^-1.On the basis of magnetic mesoporous silica were prepared by impregnation of the nuclear magnetic mesoporous silicon semiconductor photocatalyst Three ele ment system,the load of different amounts of TiO₂ photocatalytic degradation o f methylene blue performance,found that four of butyl titanate（TBOT）was add ed to the 2.5mL the highest catalytic efficiency of Fe₃O₄@SiO₂@ mSiO₂@TiO₂ photocatalyst.The study found that due to the pore structure of magnetic mesop orous silica special,make TiO₂ is limited to crystallization,in special pore intern al growth of nanoparticles,TiO₂ nanometer structure makes the photogenerated h ole electron pair recombination probability is reduced,thereby improving the phot ocarrier concentration,further improve its photocatalytic performance.By studying the degradation of methylene blue at different p H and temperature with composi te photocatalyst,it was found that the degradation efficiency of composite photoc atalyst was the highest at 25℃,pH=7.In order to further investigate the adsorption properties of magnetic mesopor ous silica,we have synthesized a mesoporous magnetic silica composite based on magnetic mesoporous silica.The surface area and pore volume of amino functio nalized magnetic core-shell microspheres were 413.46 m2·g^-1 and 0.21 cm³·g^-1,re spectively,by N₂ desorption and desorption tests.The amino functionalized magn etic mesoporous silica adsorption of Cr（VI）in the process of quasi two level d ynamic model,the adsorption of Cr（VI）is the mechanism of ion species in sol ution of Cr（VI）and the surface of amino functiona lized magnetic mesoporous si lica composite amino by means of electron sharing or electrostatic interaction.