Preparation Of Porous Silica And Its Adsorption And Catalytic Properties

Hierarchically porous materials with porosity on different length scales have exhibited high application value in the field of catalysis,adsorption,separation,and biomedicine,because of their variety of advantages,such as high specific surface area,large pore volume and interconnected hierarchical porosity.With the development of our country's economy,pollution problems due to the massive discharge of dyeing wastewater and the number of automobiles rapid increase are affecting the ecological environment.Dye wastewater has the characteristics of large discharge,complex composition and high concentration of organic compounds.The treatment of dyeing wastewater that generated in the textile process is a major problem in the industrial wastewater.The deep desulfurization of fuel oil is an important operation in the petroleum refining process.The sulfur-containing organic compounds released in the form of SO_X during combustion,which forms acid rain,haze and suspension.Therefore,this article aims to synthesize hierarchically porous materials,and explore its adsorption performance for methylene blue(MB)and catalytic performance for oxidation adsorption desulfurization.The main content is as follows.Hierarchically porous silica PAA-n were synthesized by using surfactant-polyelectrolyte(CPC-PAA)as the dynamic template,and the morphology and structure of the samples were characterized by SEM,TEM,nitrogen adsorption and XRD.The results showed that the mesoporous silica materials possessed both ordered mesopores(7 nm)and nanopores(15-50 nm).In terms of adsorption properties,the performances were examined by adsorption of dye on PAA-n materials.The results showed that the adsorption process of PAA-n for MB were fitted Fruendlich adsorption isotherm.When the initial concentration of the dye was 20mg/L,the theoretical maximum adsorption capacity of PAA-0.6 adsorbed MB was36.6 mg/g.The kinetic models indicates that pseudo-second order kinetics were well-fitted of the adsorption behavior of dyes on PAA-n materials.In addition,the study of adsorption thermodynamics showed that the adsorption process of PAA-n was exothermic.After five times regeneration of PAA-n,the removal rate of MB was still above 70%,and it had good regeneration performance.Ti-doped and Sn-doped nanospheres with hierarchically mesoporous structure were synthesized by using mesoscopic complex formed by surfactant-polyelectrolyte(CPC-PAA/CPC-PAA-P123)as template,and the morphology and structure of the samples were characterized by SEM,TEM,UV,nitrogen adsorption and XRD.The results showed that the titanosilicate nanospheres possessed highly ordered mesopores(3 nm)and large secondary mesopores(6-20 nm),and the framework Ti and Sn content reach 7.5 wt%and 3.9 wt%respectively.At room temperature,using 60 mg titanosilicate nanospheres as catalyst,30 ml of 200 ppm dibenzothiophene was completely converted into the corresponding sulfone within 20 min.Due to the nanoscale size,hierarchically mesoporous structure,and high Ti content,the hierarchically mesoporous titanosilicate nanospheres exhibited excellent oxidative desulfurization activity.