【作者】 屈文；

【导师】 苏继新；

【作者基本信息】 山东大学 ， 环境工程， 2008， 硕士

【摘要】 硅胶和介孔SBA-15均是表面富含硅羟基的二氧化硅材料,本课题围绕硅胶和SBA-15的表面改性制备了HSO₃-硅胶、SH-硅胶、TiO₂/SBA-15、Au-Ti/SBA-15,并将其应用于相应的催化反应中。以氯丙基氯硅烷和苯基氯硅烷对硅胶进行表面改性,进一步磺化得到以磺酸基为活性中心的固体酸,磺化剂分别为硫酸和亚硫酸铵。以BET、红外光谱、总有机碳对固体酸及其前驱体进行了表征并测定了固体酸酸密度;利用总有机碳计算前驱体的键合量,苯基、氯丙基硅胶键合量分别为1.40mmol/g、1.95mmol/g;以这两种前驱体制得的固体酸酸密度分别为0.32mmol/g、0.26mmol/g;BET数据表明键合反应发生后样品的比表面积变小。将制得固体酸应用于乙酸丁酯的合成,结果表明催化剂使用寿命较长,转化率和选择性较高。采用表面化学改性的方法将廉价氯丙基引入到硅胶表面,以硫氢化钠进一步改性得巯基硅胶,用BET、TOC、红外光谱、元素分析对巯基硅胶及其前驱体结构进行了表征,结果表明此制备方法得到巯基含量为1.56mmol/的材料。将所得巯基硅胶应用于含汞废水的去除和含贵金属废水的回收中,吸附实验结果表明对于Hg²⁺、Pd²⁺、Au³⁺材料饱和吸附量分别为47mg/L、87mg/g、120mg/g,且在干扰离子存在时,样品表现了良好的选择性。将硫酸钛浸渍到SBA-15孔道中,经升温原位沉淀、焙烧得到纳米孔道中均匀分散的锐钛型二氧化钛。用TEM、BET、XRD、SAXD、UV-Vis漫反射吸收光谱等方法对材料进行了表征。结果表明,改性后的SBA-15仍保持着有序的孔道,二氧化钛颗粒较均匀地分布在SBA-15孔道内部,SBA-15合适的纳米孔道对二氧化钛颗粒的长大起到较好的限制作用;紫外光下的甲基橙光降解结果表明,SBA-15负载的纳米二氧化钛颗粒有优于商品P25的光催化性能。用无水氯化物气相键合法对介孔材料进行了修饰,将Ti、Mo成功键合到SBA-15表面,并用BET、HRTEM、UV-Vis漫反射吸收光谱对材料进行了表征,结果表明金属氧化物以单层的方式均匀键合在孔道内部。以CO氧化实验为探针考察了Au-Ti/SBA-15的催化活性,结果表明材料在较宽温度范围内具有良好活性,SBA-15孔道对金颗粒聚集有较好限制作用。更多还原

【Abstract】 Silica-gel and mesoporous SBA-15 are both silica oxide material with abundance of suraface Si-OH.HSO₃-silica、SH-silica、TiO₂/SBA-15、Au-Ti₂O-SBA-15 were sybthesised by surface modification method,and these materials were applied in different catalysis rection。The phenyl and chloropropyl silica derived from chlorosilane were applied to synthesize HSO₃-functionalized silica by using H₂SO₄ or（NH₄）₂SO₃.The solid acid and their precursors were characterized by BET,IR,TOC.The surface coverage density of phenyl-silica and chloropropyl-silica were 1.40mmol/g and1.95mmol/g, while the acid exchanger capacities are 0.32mmol/g and 0.26mmol/g,respectively. The specific area of the samples decreased from 511m²/g to 406 m²/g and 432 m²/g. The solid acids were used in the synthesis of butyl acetate,and the results indicated that the catalysts can be reused for 5 times with high conversion.Thiol-functionalized silica has been prepared by cheaper chloropropyl trichlorosilane and NaSH successfully instead of expensive mercaptosilylating agent. The silica-SH and its precursor are characterized by BET,FT-IR,TOC and element analysis.Surface coverage density of silica-chloropropyl and silica-SH is 2.5mmol/g and1.56mmol/g,respectively.The silica-SH is used as sorbent to fix heavy metal ions,and the saturated adsorption capacity for Hg²⁺,Pd²⁺,Au³⁺were 47mg/L、87mg/g、120mg/g respectively,so it is an excellence material for fixation of mercury from wastewater and waste solid.Nanocrystalline anatase TiO₂ limited within the mesoporous channels of SBA-15 has been prepared by in-situ hydrolysis precipitation of Ti（SO₄）₂ solution and calcination subsequently.The as-synthesized samples were characterized by TEM, BET,XRD,SAXD,Raman,UV-Vis,XPS,XRF techniques,and the results indicated that nano-TiO₂ particles were restricted within the channel and dispersed uniformly without block the pores.The Raman and XPS data indicated that most TiO₂ particles are deposited on the support without forming Ti-O-Si bond.The activities of the samples were evaluated by the photo degradation of methyl orange under UV-light.The results showed that the TiO₂ contents and the size of particles on the support of SBA-15 affected the catalytic activity obviously,and the samples with TiO₂ particles size about 6～7nm showed the best catalytic activity.Little difference of the activity was observed between the fresh sample and the sample used for 5 times.TiO₂ and Mo₂O₃ were attach to the surface of SBA-15 by gas-phase surface modification using their chloride as precursors.The samples are characterized by BET, HRTEM,UV-Vis diffuse reflection absorption spectrum.The results indicated that Ti、Mo are in the channel of the SBA-15 without block it.The Au/Ti-SBA-15 are used to used in the oxidation of CO,and the results indicated that the catalysts in a wide range of temperature and the SBA-15 confined the growth of Au particles.更多还原