Synthesis And Application Of Hollow Mesoporous Silica By Template Method

Over the past few decades,due to the potential applications of catalysis,adsorption,separation,environmental pollution control,drug delivery,imaging,sensors,the mesoporous materials have attracted great interests.The hollow mesoporous nano-microspheres with hollow and mesoporous structure have been widely concerned because of their stronger molecular load-carrying capacity and higher activity of nano reactors.However,this kind of material is faced with the problems of completed synthetic steps and low production.In this thesis,the method of rapid synthesis of hollow mesoporous nanospheres was explored,and then a series of researches on the functionalization of nanospheres were carried out and the following research results:1.The hollow mesoporous silica nanospheres were prepared rapidly by using polyacrylic acid(PAA)as the hollow template,Pluronic F127 was introduced as the pore forming agent in alkaline ethanol system with TEOS(tetraethoxysilane)as the silicon source.The effects of stirring speed and Pluronic F127 amount on the morphology and specific surface area of hollow mesoporous Si02 nanospheres were systematically studied.The transmission electron microscope(TEM)and BET studies show that by adjusting the amount of F127 the specific surface area can be effectively controlled.Data analysis showed that the amount of PAA and F127 was 0.7 g,and the stirring speed was 450 rpm.The SiO2 nanoparticles showed the best morphology and the specific surface area was the largest,reaching 692.464 m2/g.2.The adsorption properties of the uranyl ion were investigated by the functionalized modification of nanospheres by amination.The adsorption kinetic curve shows that the adsorption equilibrium of nanospheres can be reached by 30min under the condition of pH=6,and the maximum adsorption capacity is 489mg U/g Sorbent.On the basis of aminated nanospheres,salicylaldehyde was grafted onto nanospheres via Schiff base reaction to investigate the adsorption capacity of uranium at low concentration.It is found that nanospheres can completely adsorb 5mg/L uranyl ions in 15min.The fluorescence properties of salicylaldehyde functionalized nanospheres were further studied.The data indicate that the modified hollow mesoporous SiO2 nanospheres can effectively detect Al3+ ions in aqueous solution with a detection limit of 1.19×10-7 M.3.The Fe3O4 @ HMS was synthesized by an "in situ" approach,and the synthesized material was well characterized using XRD,N2 adsorption-desorption isotherm,TEM,analysis.The catalytic performance of Fenton like reaction has been systematically studied.The results show that the catalytic effect is the best under the condition of H2O2/Fe3O4 @ HMS 6mL/40mg,and the degradation rate of methylene blue in 100mg/L reaches 98.02%within 150min.