溶致液晶模板法制备介孔氧化铝

发布时间：2018-03-01 15:01

  本文关键词： 溶致液晶 介孔氧化铝 表面活性剂 模板法　出处：《内蒙古工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：介孔氧化铝是一种优于传统氧化铝新兴材料,因其具有比表面积大、孔径分布集中、热稳定性高、易于参杂、可负载多种金属等特性,越来越多的被用于催化、吸附分离、生物医药等领域。溶致液晶模板法是软模板法的一种,用溶致液晶模板法制取介孔材料,易于操作,粒度可控,通过改变模板可以改变粒子型态、产物形貌及比表面积,是近年来研究的热点。本文采用溶致液晶模板法制备介孔氧化铝,分别构建SDS/C5H11OH/H2O和CTAB/C10H21OH/H2O三元体系的溶致液晶模板。考察了表面活性剂浓度、助溶剂浓度以及二次水含量对溶致液晶相结构的影响。在SDS:C5H11OH=8:2,二次水含量为50%的比例下,SDS/C5H11OH/H2O呈现层状的溶致液晶相;在CTAB:C10H21OH=5:5,二次水含量为60%的比例下,CTAB/C10H21OH/H2O呈现层状的溶致液晶相,由于在SDS/C5H11OH/H2O体系下形成的溶致液晶相分布均匀,确定采用SDS/C5H11OH/H2O体系作为模板以氯化铝为铝源,氨水为沉淀剂,替代体系中的水,考察了铝源的浓度、沉淀剂的质量分数对模板形成的影响以及焙烧温度对氧化铝形貌的影响。焙烧温度过高,导致孔坍塌,不利于结晶。采用热重(TG-DSC)、X-射线衍射仪(XRD)、红外光谱仪(FTIR)、比表面积测定仪(BET)、扫描电子显微镜(SEM)等测试手段进行表征。研究结果表明,XRD和FTIR测试结果表明制备的样品为氧化铝,在氯化铝浓度为0.5mol/L、氨水质量分数为25%时能够得到层状的溶致液晶相。焙烧温度为700℃的条件下得到样品为γ-Al2O3,BET测定该样品的平均孔径为6.5nm,比表面积为400 m2/g左右,达到介孔物质的要求。
[Abstract]:Mesoporous alumina is a better material than traditional alumina, because of its large specific surface area, concentrated pore size distribution, high thermal stability, easy to be mixed, and can be loaded with many kinds of metals, it is more and more used in catalysis, adsorption and separation. Lyotropic liquid crystal template is a kind of soft template method. Mesoporous materials can be prepared by lyotropic liquid crystal template method, which is easy to operate and can be controlled in size. By changing the template, the particle shape, product morphology and specific surface area can be changed. In this paper, mesoporous alumina was prepared by lyotropic liquid crystal template method. The lyotropic liquid crystal templates of SDS/C5H11OH/H2O and CTAB/C10H21OH/H2O ternary systems were prepared respectively. The concentration of surfactant was investigated. Effects of the concentration of cosolvent and the content of secondary water on the structure of lyotropic liquid crystal phase. SDS / C _ 5H _ (11) H / H / H _ 2O presents a layered lyotropic liquid crystal phase at the ratio of 8: 2 and 50% of SDS / C _ 5H _ (11) H / H _ 2O, and at the ratio of CTAB / C _ (10) H _ (21) H _ (5) / H _ (5) and C _ (TAB) / C _ (10) H _ (11) H / H / H / H / H / H / H / H / H _ 2O, the liquid crystal phase appears as layered lyotropic liquid crystal phase. Due to the uniform distribution of lyotropic liquid crystal phase formed in SDS/C5H11OH/H2O system, the concentration of aluminum source was investigated by using SDS/C5H11OH/H2O system as template, aluminum chloride as aluminum source and ammonia water as precipitant, instead of water in the system. The influence of the mass fraction of precipitator on the formation of template and the effect of calcination temperature on the morphology of alumina. TG-DSC-X- ray diffractometer, FTIR, BET and SEM were used to characterize the samples. The results showed that the samples prepared were alumina. The lamellar lyotropic liquid crystal phase can be obtained when the concentration of aluminum chloride is 0.5 mol / L and the mass fraction of ammonia water is 25. The average pore size of the sample is 6.5 nm and the specific surface area is about 400 m2 / g when the calcination temperature is 700 鈩，

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