【作者】 赵娜；

【导师】 魏坤；

【作者基本信息】 华南理工大学 ， 材料学， 2010， 硕士

【摘要】 六方介孔固体HMS (hexagonal mesoporous silica)是具有六方结构的介孔二氧化硅分子筛,是以长链伯胺为模板剂,在中性条件下合成出的六方介孔分子筛，具有较大的比表面积和较大的孔容,孔径大小均一。相对于其它分子筛来说,HMS具有较厚的骨架内壁和较丰富的表面羟基,HMS在合成过程中由于使用了比较温和的模板剂去除方法,所以模板剂可以回收进行循环利用,可以降低成本和减少环境污染,所以广泛应用于催化、吸附、分离以及传感器、分子工程、纳米复合材料等方面。然而,在实际应用当中,如果仅仅依靠HMS的吸附性还远远不能满足要求,因此,可以通过表面改性将有机或无机基团引入分子筛,提高其吸附的选择性,使其有更广泛的应用。本研究采用分子自组装合成法,用长链伯胺十二胺(DDA)为模板剂,以正硅酸乙酯(TEOS)为硅源,室温下合成了大比表面积的中孔分子筛HMS,用PEG及稀土元素镧掺杂改性HMS,并用XRD、SEM、TEM、红外光谱(FTIR)、TG、N2吸附等对材料进行了表征,研究了材料在降低香烟中焦油含量方面的应用,并对采用细胞毒性实验对材料的细胞毒性进行了检测。结果表明：(1)以长链伯胺为模板剂,在中性条件下合成出的六方介孔分子筛,具有较大的比表面积(1478.95m2g-1)和较大的孔容,孔径大小均一,其粒子均为球形,孔结构象蜂巢,可以作为理想的纳米主体用于客体纳米材料的构筑；(2)掺杂后的La-HMS仍保持原来的介孔结构。材料可以均匀地分散到介孔二氧化硅的基质中。在合成La-HMS介孔固体时,模板剂与硅酸盐之间有很强的相互作用,稀土离子的加入有利于促进介孔固体硅羟基的凝聚,使Si与O(H2O)的作用减弱,960cm-1带的存在,并不能直接用来证明稀土离子已掺入HMS介孔固体。EDS表明没有新的元素出现,证明稀土离子已掺入HMS介孔固体。掺杂材料的比表面积有所减小,但仍保持较大的比表面积,La-HMS的比表面积分别为1020.12m2g-1。与原材料相比,掺杂稀土金属镧后的材料应用于香烟中有更好的吸附性；(3)改性后的PEG-HMS也保持原来的介孔结构,PEG的加入没有破坏材料的介孔结构。PEG是靠氢键吸附在HMS颗粒表面,两者并没有发生化学反应生成新的化合物；改性后的材料比表面积有所减小,但仍保持较大的比表面积,PEG-HMS的比表面积为1015.65m2g-1。制备的PEG-HMS复合材料的热稳定性比PEG有所提高。复合材料PEG-HMS的细胞相容性比HMS有所提高,且没有毒性。通过两种材料的复合,得到的新I的复合材料,兼具两种材料的优点,在选择性吸附香烟中有害物质的方面有很好的应用。(4)初步采用HMS、La-HMS及PEG-HMS作为添加剂加入到香烟中,发现材料对卷烟烟气中的焦油和烟碱,具有一定的吸附和降解作用,但作为工业产品开发还需进一步的研究。(5)通过MTT法的测定结果可知,本实验制备的材料没有毒性。细胞毒性程度为0～1级,与对照组无显著差异,而且随着时间的增长,细胞在第5天,第7天的增殖率超过了对照组细胞,可见材料利于细胞的增殖,这可能与材料结构有关。本实验用的材料为六方介孔材料,材料的介孔结构利于细胞的黏附,且材料本身无毒性,利于细胞增殖。可见,材料可以用作香烟添加剂,在生物医药方面也具有十分好的前景。更多还原

【Abstract】 HMS (hexagonal mesoporous silica) synthesized under neutral conditions based on long-chain primary amine as template is a hexagonal structure mesoporous silica molecular sieve with large surface area, large pore volume, and uniform pore size. Compared to other molecular sieve, HMS has thick frame walls and abundant surface hydroxyl groups. Furthermore we adopted a relatively mild template removal method in the HMS synthesis process and the template is recyclable, reducing costs and environmental pollution. Therefore it is widely used in the field of catalysis, adsorption, separation,sensors, molecular engineering, nano-composite materials and so on. However, molecular sieves with simplex adsorption of HMS can not meet the requirements in the practical application. By surface modification introducing organic or inorganic groups into molecular sieves,we can improve its adsorption selectivity and widen its applications.In this study, we synthesized a large surface area mesoporous molecular sieve HMS at room temperature with molecular self-assembly synthesis, using long chain primary amine dodecylamine (DDA) as template agent and TEOS (TEOS) as silica source. Then HMS was modified with Lanthanum doped and PEG. XRD, SEM, TEM, infrared spectroscopy (FTIR), TG, and N2 adsorption were used to characterize the materials. We also studied the effects of the material in reducing tar content of cigarettes, and detected the toxicity of the materials with cytotoxicity experiment. The results showed that:(1) Using long-chain primary amine as template, the hexagonal mesoporous molecular sieves can be synthesized,which are spherical particles with honeycomb pore structure under neutral conditions, with large surface area (1478.95m2g-1), large pore volume, and uniform pore size.,and can be used as an ideal subject for nano-objects to build nano-materials;(2) Doped La-HMS kept the original mesoporous structure. Doped Materials can be evenly distributed in mesoporous silica matrix. In the synthesis of La-HMS mesoporous solid process, there is strong interaction between the template and silicate. Rare earth ions is helpful to promote the condensation of silanols of the mesoporous solid and so reduce the Si and O (H2O) interaction. The presence of 960cm-1 band can not be directly used to prove that rare earth ions have been doped into HMS mesoporous solid. EDS showed that no new element appears, which means rare earth ions have been doped into HMS mesoporous solid. Though doped materials have reduced its surface area, but it still maintains a large surface area. The surface area of La-HMS is 1020.12m2g-1. Compared with the raw material, rare earth lanthanum doped material used in cigarettes has a better adsorption. (3) the modified PEG-HMS also maintained the original mesoporous structure, the added PEG did not destroy the mesoporous structure. PEG is adsorbed on the HMS particle surface by hydrogen bonding,which do not have no chemical reaction. The modified material surface area decreased slightly, but still maintains a large value, PEG-HMS specific surface area is 1015.65m2g-1. Thermal stability of PEG-HMS composites increased compared to the PEG Cell compatible of PEG-HMS Composite improved compared to HMS, and it is no toxicity. A new composite material with both the advantages of the two materials was produced by combining two materials. Its selective adsorption has a good application in adsorpting harmful substances in cigarettes.(4)HMS, La-HMS and PEG-HMS was added into cigarettes in the initial study. And it was found that the additive materials have certain effect in absorption and degradation for smoke tar and nicotine in cigarette. But it needs further study before it was used as an industrial product.(5)MTT results showed the prepared materials in this study are not toxic.Toxicity levels range from 0 to1, with no significant difference compared to the control group. At the 5th day,and the 7th day, the proliferation rate of cells exceeded over the control, indicating the material is favorable to the cell proliferation, which may be related to the material structure. In this study hexagonal mesoporous materials was adopted. The mesoporous structure is conducive to cell adhesion. And the material itself is non-toxic, which is beneficial to cell proliferation. Accordingly, the hexagonal mesoporous materials can be used as cigarette additives; it also has very good prospects in biological medicine.更多还原