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1.
氨基功能化短孔道有序介孔材料H_2N-Zr-Ce-SBA-15的合成及吸附性能 总被引:2,自引:0,他引:2
以pluronic(P123)为模板剂,正硅酸乙酯(TEOS)为硅源,氯化氧锆和硝酸亚铈为无机前驱盐,N-(2-氨乙基)-3-氨丙基三甲氧基硅烷(AAPTS)为硅烷化试剂,采用后接枝法合成了氨基功能化六方板状短孔道有序介孔材料H2N-Zr-Ce-SBA-15(H2N-ZCS).采用小角X射线衍射(LXRD)、傅里叶变换红外(FTIR)光谱、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、热重分析、N2吸附/脱附等手段对H2N-ZCS进行了表征.结果表明AAPTS成功地嫁接到有序介孔材料上,H2N-ZCS仍保持了类似于传统SBA-15高度有序的二维六方相介孔结构,且孔道方向垂直于该六方板面.对阴离子染料酸性品红吸附实验表明,H2N-ZCS比H2N-SBA-15具有较强的吸附能力.这种功能化短孔道、大径轴比的六方板状介孔材料在吸附、分离及催化等领域中能更有效地促进分子的扩散传递. 相似文献
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采用三嵌段共聚物EO20PO70EO20(P123)为模板剂,正硅酸乙酯(TEOS)和缺位Keggin型多金属氧酸盐Na7PW11O39(PW11)为无机前驱体,由共缩合法一步合成了PW11/SBA-15介孔杂化材料.通过红外(IR)光谱、紫外-可见漫反射光谱(UV-Vis/DRS)、X射线衍射(XRD)、低温N2吸附、透射电子显微镜(TEM)等手段对杂化材料和合成过程进行了表征.结果表明:杂化材料中不仅多金属氧酸盐的Keggin单元保留完整,且共价键联于介孔孔道内部,而且样品基本具有规整有序的六方介孔结构.TEOS预水解时间的长短对有序结构的构筑有明显影响,随预水解时间延长,样品的介观有序性增加.这是因为多金属氧酸盐对模板剂P123有盐析作用,其作用大小与多金属氧酸盐前驱物的溶解度有关. 相似文献
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《中国科学:化学》2016,(4)
以正硅酸乙酯(TEOS)为硅源,P123为模板剂,通过加入适量HAc及调整反应体系pH方式,采用水热及萃取法合成表面羟基含量较高的介孔SBA-15材料.以不同含量四乙烯五胺(TEPA)对SBA-15进行功能化,获得氨基功能化介孔SBA-15材料.利用X射线衍射(XRD)、N2吸-脱附、傅里叶红外光谱(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、元素分析等手段对材料结构性能进行表征.以不同含量TEPA功能化介孔SBA-15为吸附剂,对CO_2进行吸附,考察了吸附温度、CO_2浓度、水等对吸附效率的影响.实验结果表明,常温、常压下30%TEPA功能化介孔SBA-15的CO_2吸附量最高,且重复使用性能良好. 相似文献
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HCl对有序介孔氧化硅结构与形貌的影响 总被引:4,自引:0,他引:4
以三嵌段共聚物P123为有机模板导向剂、正硅酸乙酯TEOS为无机硅源, 在HCl存在的强酸性环境下, 采用水热法合成了有序介孔分子筛SBA-15. 采用XRD、SEM、TEM、N2吸附-脱附等手段对产物的结构与形貌进行了分析, 考察了HCl用量对有序介孔材料结构及形貌的影响. 结果表明, 在合成有序介孔氧化硅时, HCl发挥了催化和中间离子的双重作用, 促使棒状胶束形成六方有序排列, 降低SBA-15中微孔的数量, 而且对合成有序介孔氧化硅SBA-15的形貌有显著影响. 适宜的HCl用量对形成“珍珠链状”形貌的、热稳定性优良的SBA-15介孔材料具有重要作用. 相似文献
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通过直接合成方法制备了2个二级胺功能化的SBA-15型有机-无机杂化碱性介孔材料. 粉末X射线衍射分析、氮气吸附-脱附和透射电镜表征表明, 合成的材料保持了SBA-15的有序介孔孔道结构, 而热重、红外光谱和元素分析表明有机功能团被成功引入. 在对硝基苯甲醛和丙酮的羟醛缩合反应中, 相对于一级胺功能化的材料, 二级胺功能化的SBA-15展示了极大改进的催化活性, 这可能是由于具有更大空间位阻效应的有机功能团的引入导致了碱性胺中心催化活性增强. 相似文献
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采用嵌段共聚物模板P123和缺位Keggin结构的多金属氧酸盐K8SiW11O39•12H2O, 由溶胶-凝胶法合成了具有类六方结构的SiW11/SBA-15杂化介孔分子筛材料, 并通过X射线衍射(XRD)、傅立叶变换红外光谱(FT-IR)、紫外漫反射光谱(UV/DRS)、电感耦合等离子原子发射光谱(ICP-AES)、低温N2吸附、透射电子显微镜(TEM)等手段对其进行了表征. 结果表明, 杂化材料中不仅规整均一的类六方介孔结构得以保持, 而且多金属氧酸盐的Keggin单元保留完整(含量达25%左右), 并共价键联于介孔材料的孔道内部. 稳定性实验表明, 杂化材料中多金属氧酸盐在水中的流失率远低于一般浸渍法制备的样品. 相似文献
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通过蒸汽诱导内部水解法(VIH)在介孔分子筛SBA-15孔壁上引入Al_2O_3,合成得到Al_2O_3@SBA-15复合物,随后与对二苯甲酸配体反应,从而制备得到金属有机框架化合物(MIL-53)与介孔分子筛(SBA-15)复合材料(MIL-53@SBA-15)。采用粉末X射线衍射(PXRD)、N_2吸附-脱附测试、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等技术证明成功合成了MIL-53@SBA-15复合材料。染料吸附实验结果表明,MIL-53@SBA-15复合材料相比于SBA-15、MIL-53及其物理混合样品,表现出对丁基罗丹明染料更高效吸附特性。 相似文献
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杂化硅胶整体材料研磨法制备混合型高效液相色谱固定相 总被引:1,自引:0,他引:1
以聚乙二醇(PEG)为致孔剂,四甲氧基硅烷(TMOS)和乙烯基三甲氧基硅烷(VTMS)为杂化硅胶前驱体,在乙酸催化作用下使硅烷发生水解,在尿素加热分解提供的碱性环境下水解的硅烷进一步缩聚得到杂化硅胶整体材料。将此整体材料用球磨机研磨,然后用三羟甲基氨基甲烷处理,并洗涤干燥得到粒径为3 μm左右的硅胶颗粒。探索了不同反应条件对硅胶颗粒的大小、比表面积和孔径、表面形貌和分散性的影响;当TMOS和VTMS体积比为3:1时可以得到孔径为7.5 nm和比表面积为245 m2/g的硅胶颗粒。通过对所制得的硅胶颗粒表面进行C18(十八烷基二甲基氯硅烷)键合修饰和巯基-烯点击反应,得到混合型高效液相色谱固定相。对此固定相的测试结果表明以上硅胶色谱填料的制备方法具有一定的实用性。 相似文献
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Usha Ghimire Gautam Mani P Gautam Tsuyoshi Sawada Makoto Takafuji Hirotaka Ihara 《Analytical sciences》2008,24(5):615-621
Poly(4-vinylpyridine)-modified silica with high grafting density have been prepared by a grafting-from (g-from) approach through radical chain-transfer reactions. The widely used silane coupling agent 3-mercaptopropyltrimethoxysilane was used to prepare thiol-terminated silica. Chain-transfer reaction and polymerization of 4-vinylpyridine was carried out using alpha,alpha'-azobisisobutyronitrile as an initiator. Thiol-terminated silica and polymer-modified silica were both characterized qualitatively and quantitatively. The quantification of the organic phase has been done by thermogravimetric analysis and elemental analysis. Thus, the modified silica was used as a packing material and the retention behavior of polycyclic aromatic hydrocarbons (PAHs) was studied in normal-phase high-performance liquid chromatography. Results were compared with those of poly(4-vinylpyridine)-modified silica prepared by a grafting-to (g-to) approach. Commercially available aminopropyl-bonded silica and bare silica columns were also used as reference columns. The column of poly(4-vinylpyridine)-grafted silica prepared by the g-from method, having higher grafting density, provided the better retentivity and selectivity for PAHs compared to the other reference columns. 相似文献
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We demonstrate a facile method of fabricating opal and inverse opal structures with a planar defect. A single layer of silica beads was embedded into polystyrene opals by combining an inward-growing self-assembly method with spin-coating technique. After the infiltration of silica followed by the removal of the polystyrene beads by calcination, an inverted structure was obtained. The silica beads were connected together by the infiltrated silica, thus a solid silica phase with the silica beads as a planar defect embedded in the inverse silica opal was obtained. The thickness of the defect layer can be adjusted by changing the size of the silica beads. Scanning electron microscope images showed the good quality of the crystal and the uniformity of the defect layer. Optical transmission spectra indicated the existence of a defect state induced by the defect layer in both the opal and inverse opal structures. High-cost techniques such as lithography and chemical vapor deposition are not involved in the fabrication of inverse opals with planar defects. 相似文献
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以蛋白质或多肽修饰的吲哚类菁染料Cy3为内核, 采用实验条件简单的油包水反相微乳液方法成核, 通过正硅酸乙酯水解形成的网状二氧化硅包壳的方法制备吲哚类菁染料Cy3嵌入的核壳荧光纳米颗粒. 考察了以不同等电点的蛋白质和多肽修饰的Cy3为内核材料对吲哚类菁染料Cy3嵌入的核壳荧光纳米颗粒制备的影响. 结果表明, 分别采用人免疫球蛋白(IgG)或多聚赖氨酸修饰的Cy3为内核材料, 都能制备荧光强度高、荧光稳定性强和染料泄漏极少的Cy3嵌入的核壳荧光纳米颗粒. 进一步对Cy3嵌入的核壳荧光纳米颗粒进行了表征, 并将基于这一新型的荧光纳米颗粒建立起来的生物标记方法初步应用于流感病毒DNA的检测, 其检测线性范围为3.18×10-10~1.27×10-9 mol/L, 检测下限为3.51×10-10 mol/L, 相关系数r为0.986 5. 相似文献
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A series of silicone resin/silica polymeric nanocomposites with 0–6 wt% silica content, comprising well-distributed silica nanoparticles in silicone resin matrix, have been synthesized from a UV-curable polysilisiquioxane (UV-PSL) and a methacrylate-functionalized silica via UV-curing in the presence of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184) as photoinitiator. To enhance the interfacial interaction, the silica surface was firstly treated with 3-(methacryloxy) propyl trimethoxysilane (MPTS), and its structure was analyzed by FTIR spectrophotometry. The thermal stability of nanocomposites was slightly enhanced with the addition of silica particles. SEM studies indicate that silica particles were dispersed homogenously through the polymer matrix. The physical and mechanical properties such as the thickness, hardness, adhesion, impact strength as well as gloss were examined. 相似文献
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源自水稻壳的高比表面纳米二氧化硅负载12-磷钨酸:一种高效纳米催化剂用于几种有机反应(英文) 总被引:1,自引:0,他引:1
Nano silica was prepared from rice husk with high surface area.X-ray diffraction(XRD) pattern showed that the amorphous form of silica was produced.Chemical composition of the nano silica was estimated by X-ray fluorescence spectroscopy and CHN analysis.The nano silica was used as a support for H3PW12O40.The nano silica and nano silica supported H3PW12O40 were characterized by inductively coupled plasma,XRD,transmission electron microscopy(TEM),N2 adsorption-desorption,and Fourier transform infrared spectroscopy.TEM images of nano silica as well as the supported catalyst displayed average size of 6 and 7 nm,respectively.The catalyst showed excellent activity in some important organic reactions including Biginelli,Hantzsch,Mannich,and Claisen-Schmidt reactions with good reusability.Catalytic activity of this nano catalyst is an improvement over the commercially available silica that is used to support H3PW12O40. 相似文献
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以高无机含量SiO2/聚甲基丙烯酸甲酯(PMMA)接枝复合材料为预分散母料,与PMMA树脂进行熔融共混,制得低无机含量的SiO2/PMMA复合材料.通过切片透射电镜(TEM)观察熔融共混过程中预分散母料内堆积SiO2粒子分散状态的演化.发现预分散母料接枝状态对其影响最为显著,不经接枝修饰的SiO2粒子经熔融共混后,不可避免地会在熔体中产生大量亚微米级的立体团聚体;复杂接枝预分散母料内构成以SiO2粒子为交联点的立体交联结构,其中的堆积SiO2粒子不能在剪切场中得到有效解离和释放;只有在使用简单接枝预分散母料时,基体高分子链才能不断地渗透扩散进入预分散母料内,而预分散母料可被不断地溶胀和撕裂,因而其中的堆积SiO2才可不断地向基体相迁移和扩散,并最终在整个复合材料内实现初级粒子形式的高度均匀稳定分散. 相似文献
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A facile method for introducing mesoporous silica sublayer onto the surface of a ceramic membrane for use in liquid-phase separation is described. To reduce the electrostatic repulsion between the mesoporous silica sol and the ceramic membrane in highly acidic conditions (pH < 2), thus facilitating the approach of hydrolyzed silica sol to the surface of the membrane, poly(sodium 4-styrenesulfonate) (Na+PSS-, denoted as PSS-) was used as an ionic linker. The use of PSS- led to a significant reduction in positive charge on the ceramic membrane, as confirmed by experimental titration data. Consistent with the titration results, the amount of mesoporous silica particles on the surface of the ceramic membrane was low, in the absence of PSS- treatment, whereas mesoporous silica sublayer with hierarchical pore structure was produced, when 1 wt % PSS- was used. The results show that mesoporous silica grows in the confined surface, eventually forming a multistacked surface architecture. The mesoporous silica sublayer contained uniform, ordered (P6 mm) mesopores of ca. 7.5 nm from mesoporous silica as well as macropores ( approximately mum) from interparticle voids, as evidenced by transmission electron microscopy and scanning electron microscopy analyses. The morphologies of the supported mesoporous silica could be manipulated, thus permitting the generation of uniform needlelike forms or uniform spheroid particles by varying the concentration of PSS-. 相似文献
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Masayoshi Satoh Kumi Shirai Hiroshi Saitoh Takeshi Yamauchi Norio Tsubokawa 《Journal of polymer science. Part A, Polymer chemistry》2005,43(3):600-606
The photograft polymerization of various vinyl monomers onto nanosized silica surfaces was investigated. It was initiated by eosin moieties introduced onto the silica surface. The preparation of the silica with eosin moieties was achieved by the reaction of eosin with benzyl chloride groups on the silica surface.These were introduced by the reaction of surface silanol groups with 4‐(chloromethyl)phenyltrimethoxysilane in the presence of t‐butyl ammonium bromide as a phase‐transfer catalyst. The photopolymerization of various vinyl monomers, such as styrene, acrylamide, acrylic acid, and acrylonitrile was successfully initiated by eosin moieties on the silica surface in the presence of ascorbic acid as a reducing agent and by oxygen. The corresponding polymers were grafted from the silica surface. The grafting efficiency (percentage of grafted polymer to total polymer formed) in the photoinitiation system was much larger than that in the radical polymerization initiated by surface radicals; these radicals were formed by the thermal decomposition of azo groups introduced onto the silica surface. It was found that the polymer‐grafted silica gave stable dispersions in good solvents of grafted polymer and the wettability of the surfaces can be easily controlled by grafting of polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 600–606, 2005 相似文献
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Jin‐Xing He Guo‐zhen Fang Yu‐chao Yao Shuo Wang 《Journal of separation science》2010,33(20):3263-3271
In this work, a novel approach of preparing molecularly imprinted film‐derivatized silica monolith materials was developed by a two‐step procedure. The silica monolithic support was first prepared by the sol–gel method with tetramethoxysilane as the precursor. Subsequently, vinyl groups were introduced onto the surface of silica monolith by immobilization of γ‐methacryloxypropyltrimethoxysilane. The prepolymerization mixtures, consisting of methacrylic acid as a functional monomer, ethylene dimethacrylate as a crosslinker, sulfamethazine as a template molecule and an ionic liquid as porogen, were injected into the silica monolith immobilized vinyl groups to form the molecularly imprinted films on the surface of the vinyl functionalized silica monolith. The monolithic materials were characterized by SEM, Fourier transform IR and solid‐state reflection UV spectra. The resulted imprinted materials were evaluated under CEC and HPLC mode. The results indicated that there were enough recognition sites on the surface of the imprinted film‐derivatized monolithic materials for selectively recognizing sulfamethazine from the sulfonamide mixture. Ionic liquids, which was utilized as the porogens, could improve the flow‐through property and the imprinting effect of the molecularly imprinted film‐functionalized silica monolithic materials. 相似文献