Synthesis And Application Of Functionalized Mesoporous Silica In Weak Acidic Medium

Mesoporous silica has become a hot topic in many areas since it has been successfully developed in last 3 decades.In this thesis,we focus on the the direct synthesis of mesoporous silica and realted materials in weak acid system,and the application of those materials in adsorption,photo-catalysis of dye from model wastewater.A series of aluminum-containing mesoporous silica materials were synthesized by using Al salts as additive instead of traditional strong acid or alkali.During the synthesis,inorganic Al species could be hydrolyzed and the self-generated weak acidity,which is benifical for both the phase formation of mesopores and the introduction of a certain amount of aluminum.On this basis to further study doping transition metal elements Fe and Cu into the aluminum-containing mesoporous silica materials,and changing the molar ratio of the Fe/Si and Cu/Si to explore the material structure,photocatalytic degradation of dye wastewater was investigated.Finally,the synthesis method was changed to synthesize mesoporous silica with different morphologies,exploring the adsorption properties of mesoporous silica with different morphologies on the dye wastewater.Using the XRD,SEM,TEM and N2 adsorption –desorption test method and so on to research the effects of the Al/Si molar ratio,doping,synthetic methods on pore structure,size and surface morphology,influence on the removal of dyes capacity in water.The results showed that introduction of inorganic salt AlCl3 can produce weak acid environment,it can be a good way to synthesize mesoporous silica,which pore in a certain range of Al/Si molar ratio with a high degree of regularity and order.Methylene blue(MB)and Rhodamine B(RhB)were used to simulate the dye molecules,the adsorption performance of the material on the dye wastewater showed a certain regularity with the changes of the mole ratio of Al/Si The best ratio is Al/Si=0.5,the maximum adsorption capacity is 166mg/g.In the dual system with dye wastewater,aluminum-containing mesoporous silica exhibited certain selectivity,the adsorption rate and adsorption capacity of the Rh B are both greater than MB.Doped with transition metals Fe and Cu,ordered mesoporous structure of the material can be maintained at low Fe/Si and Cu/Si molar ratio,and the photocatalytic degradation property of the dye wastewater is strong.