有机/无机复合介孔膜的合成及其生物酶吸附行为研究

以正硅酸四乙酯(TEOS)为硅源、三嵌段共聚物(F127)为表面活性剂, 聚碳酸酯膜为硬模板, 并采用抽滤法在聚碳酸酯膜内的亚微米级孔道中组装介孔氧化硅从而制备出有机(聚碳酸酯)/无机(介孔氧化硅)复合介孔膜. 通过扫描电镜、能量分散光谱以及透射电镜等实验表征了该有机/无机复合介孔膜的组成、结构及形貌. 研究结果表明: 通过该方法可以在聚碳酸酯膜内孔道中形成长度为9 μm、直径为200 nm的一维氧化硅棒状材料, 且该棒状材料具有无序蠕虫状和有序体心立方的混合介孔结构, 有序体心立方介孔的平均孔径约为8.5 nm. 另外, 初步考察了该复合介孔膜对生物酶的物理吸附行为, 结果表明其对肌红蛋白酶的单位吸附负载量为5.85 mg/g.     

有机官能化MSU-x孔分子筛的界面特征

MSU- x是自 M41S系列介孔分子筛问世以来所合成的另一类新型介孔分子筛材料 ,它具有三维立体交叉排列的 " worm- like"孔道结构特征及采用中性模板剂、廉价无毒等诸多合成优点 [1～ 4],有着潜在的应用价值 .为了改善纯硅的介孔材料的表面和孔道性质 ,扩大其应用领域 ,除了在骨架引入金属离子或在其孔道中负载催化活性物质外 ,对介孔材料进行有机官能化制备无机-有机杂化材料改善其骨架和孔道性质是当前研究的热点之一 [5].正是由于活性有机基团的存在 ,使得这些材料可直接用于催化反应 ,或作为中间介质成为其它络合离子的主体 .由于有机基…     

磺酸基功能化MCM-41有机-无机杂化材料的合成与表征

 利用直接合成法和后接枝法将含有磺酸基团的硅烷偶联剂引入MCM-41介孔分子筛中, 合成了酸性介孔有机-无机杂化材料. 利用XRD和TEM等方法对其结构进行了表征. 结果表明,利用直接合成法和后接枝法合成的杂化材料仍保持规整的介孔孔道,该材料作为酸催化剂在苯甲醛与乙二醇的缩醛反应中显示了较好的催化活性.     

三头季铵盐表面活性剂导向合成新型立方相介孔二氧化硅

介孔分子筛因具有大而均一的孔道、高比表面积及相对良好的热稳定性而在精细化学品催化剂[1,2 ] 、生物大分子分离 [3] 和功能材料的主体 [4 ] 等领域有十分广阔的应用前景 .自 1 992年 Mobil公司合成 M41 S[5,6 ] 系列介孔材料以来 ,HMS[7] ,MSU[8] 和 SBA[9～ 12 ] 系列以及 FDU- 1 [13] 等不同结构的介孔分子筛材料相继被合成 .立方相介孔分子筛因具有三维网状结构和可通性较高的孔道而在反应中不易堵塞 ,相对于一维孔道结构的六角相 MCM- 41和 SBA- 1 5 ,其应用前途更加广阔 .迄今 ,人们已经合成了 MCM- 48[14～ 16 ]( Ia3d) …     

Eu(TTA)_3/MCM-41介孔复合体的溶胶凝胶法组装

利用溶胶 凝胶法将稀土配合物Eu(TTA) 3 组装到MCM 41介孔分子筛的孔道中 ,并初步认定客体分子Eu(TTA) 3 是以加合物形式包裹于表面活性剂胶束中。该法制得的介孔复合体Eu(TTA) 3/MCM 41,用XRD、HRTEM技术证实具有短程有序的、规整的六方介孔结构和大小分布均匀的纳米晶粒。对其光致发光和荧光寿命的研究发现 :与乙醇溶液中相比 ,Eu3 的荧光寿命没有发生改变 ,但Stokes位移却明显增大 ;复合体中 ,能量是从主体MCM 41传递到客体Eu(TTA) 3 上。     

有序介孔硅胶及其复合材料作固定相在液相色谱中的应用

系统地介绍了有序介孔硅胶及其复合材料的研究进展。重点评述了颗粒状无机介孔硅胶材料、颗粒状有机-无机复合介孔硅胶材料、手性介孔硅胶材料和整块介孔硅胶材料在用作液相色谱固定相方面的最新进展。对硅基有序介孔材料制备方面存在的问题进行了分析,并就该领域今后的发展趋势做了展望。     

孔道三维相互连通锐钛矿TiO2-SiO2纳米复合介孔材料的制备及其高光催化活性

本文报道一种孔道三维相互连通锐钛矿TiO2-SiO2纳米复合介孔材料的制备.该介孔材料是以两维六方有序结构、直孔道、锐钛矿70TiO2-30SiO2-950纳米复合介孔材料(于950oC晶化2 h)为前驱体, NaOH为SiO2的刻蚀剂,通过“在孔壁内造孔”的方法获得.我们的策略是采用温和的造孔条件,如稀NaOH溶液,合适的温度与固/液比等.采用X射线衍射(XRD),透射电镜(TEM)和低温N2吸附等技术对样品的介孔结构进行了系统表征.结果表明,墙内孔的密度非常高,孔径均一(平均尺寸3.6 nm),且在三维网络高度连通原孔道,但介孔结构仍保持其完整性.锐钛矿纳米晶粒的结晶度和大小在墙内造孔前后基本保持不变.该材料光催化降解罗丹明B(0.303 min–1)与亚甲基蓝(0.757 min–1)的活性相当高,此活性分别是其母体材料的5.1和5.3倍,甚至是Degussa P25光催化剂的16.5和24.1倍.这充分表明三维连通孔道结构对活性的大幅提高起了关键作用.孔道三维连通式锐钛矿TiO2-SiO2纳米复合介孔材料对上述污染物展现出意想不到的高降解活性,显著高于迄今已报道的金属氧化物基介孔材料对上述污染物的降解活性.更重要的是,该光催化剂具有相当高的稳定性和重复使用性.相信,本方法将为具有超高性能的孔道三维相互连通其它金属氧化物基介孔材料的制备铺平了道路.
　　小角XRD结果表明,母体材料的孔道是两维六方有序结构,在孔壁内造孔之后,样品原有的介孔结构仍保持其规整性.宽角XRD结果显示,二氧化钛的晶相是锐钛矿,晶粒尺寸为10.8 nm.造新孔之后,锐钛矿纳米晶粒的结晶度和大小与母体样品的相比变化不大. TEM结果显示,母体样品的孔壁内没有孔.孔道是两维六方有序排列的直孔道,孔径大小均一(平均尺寸4.1 nm).高分辨透射电镜(TEM)观察揭示,锐钛矿纳米晶粒(平均大小11.3 nm)在孔壁内随机排列,并与无定形SiO2纳米颗粒相互连接,相间共存,形成类似“砖块?水泥砂浆”砌成的孔壁,这种独特的复合骨架结构赋予其很高的稳定性.当一些SiO2纳米颗粒被去除之后, TEM观察显示,孔壁内有密集分布的孔,这些孔取向随机,并在三维方向连通原孔道,但介孔骨架结构仍保持其完整性.墙内孔的大小范围很窄(3.1?4.3 nm),平均大小为3.6 nm.高分辨TEM观察显示,锐钛矿晶粒大小与母体材料内的相比基本未变.上述结果与XRD结果一致.低温N2吸附表征结果显示,母体样品内只有一种孔道,孔径为4.0 nm.去除部分SiO2后的样品内有两种孔道,孔径分别是3.4和4.1 nm.这些结果与TEM的观察吻合.罗丹明B与亚甲基蓝在造孔前后样品内扩散速率评价结果显示,其在三维连通孔道内的扩散速率很高,大约是其母体材料内的5倍以上.这表明相互连通的孔道网络结构非常有利于客体分子在其内扩散.光催化降解性能评价结果显示,罗丹明B与亚甲基蓝在相互连通孔道内降解的速率相当高,分别是其在不连通孔道内的5.1和5.3倍.这充分证明孔道三维相互连通对活性的大幅提高起了关键作用.我们对材料的稳定性和重复使用性作了评价,经过10次循环使用孔道三维相互连通锐钛矿TiO2-SiO2纳米复合介孔材料,其吸附与光催化降解罗丹明B的性能变化不大.这充分证明本文制备的孔道连通复合介孔材料的性能是相当稳定的和可重复使用的.该方法可用于制备具有超高性能的孔道三维相互连通其它金属氧化物基介孔材料,如Nb2O5, Ta2O5等.     

有机双官能化MSU-X介孔分子筛的合成

分别在两种非离子表面活性剂的存在下,采用共水解缩聚法一步合成具有双有机官能基的MSU-X介孔材料,并对其合成过程、材料的结构和表面性质进行了系统研究.结果表明,不同的制备参数对双官能化MSU-X孔道特征、表面性质和孔结构性能均有一定的影响;有机物以共价键的方式与SiO₂骨架相连并均匀分布于孔道表面形成有机界面层.双有机官能化的介孔材料具有分形特征.     

手性有序无机介孔硅用作气相色谱固定相

手性介孔材料在手性分离、不对称催化、手性传感等领域具有广泛的应用价值。手性有序无机介孔硅是一类介孔结构高度有序、不含有机成分的手性材料。该文采用D-苯丙氨酸为手性源合成手性有序无机介孔硅(COIMS),将其用聚硅氧烷(OV-1701)稀释后用作固定相制备毛细管气相色谱手性柱,并对该手性柱的分离性能进行了考察,8种手性化合物在该手性柱上得到了拆分。COIMS柱对直链烷烃、醇的分离也表现出良好的选择性。该柱还具有分析时间短、在较高温度下测定稳定等优点,其具有开发成高温手性固定相的潜力。     

有机-无机杂化介孔二氧化硅在环境保护中的应用

将有机基团通过后嫁接或共缩聚法引入到介孔二氧化硅的孔道表面或骨架中,根据有机基团在材料中的位置可得到表面结合型和桥键型两类功能化介孔材料.本文总结了有机-无机杂化介孔二氧化硅的分类及合成方法,重点介绍了该类材料作为吸附剂在环境保护中的应用,包括金属阳离子、含氧阴离子、有机污染物和气体的去除与回收.并展望了有机-无机杂化...     

MCM-41介孔分子筛共价键联钴酞菁的制备，表征及性质

采用两种方法将钴酞菁配合物共价联接到介孔分子筛MCM-41的表面：(1) 在MCM-41表面联接含伯胺的有机侧链；(2) 是在MCM-41表面联接含仲胺的有机侧链。含氯磺酸基的钴酞菁与胺反应形成磺酰胺。对得到的主客体化合物用多种物化手段和催化反应进行了表征。结果表明，钴酞菁以单体形式固定在介孔分子筛MCM-41的孔道壁上，在反应条件下固载后的钴酞菁具有高催化活性，同时表现出良好的稳定性，多次重复使用活性没有明显的改变。     

Rapid synthesis of highly ordered Si-MCM-41

A very short-time synthesis of highly ordered MCM-41 molecular sieve was formulated by using cetyltrimethylammonium bromide (CTAB) as the template and silica gel from SiliCycle as the silica source. The physical properties of MCM-41 samples were characterized by X-ray diffraction (XRD), nitrogen physisorption, and transmission electron microscopy (TEM). The MCM-41 sample prepared in this study exhibited well defined long-range order and good hydrothermal stability. It was demonstrated that reducing the time of self-assembly step to 2 h during the synthesis had no unfavorable effect on the quality of MCM-41 materials.     

MCM-41中孔SiO2分子筛合成新方法

以溴代十六烷基吡啶（CPBr）为模板剂，正硅酸乙酯（TEOS）为硅源，在优化的操作条件下通过S＋X-I 路径合成了高结晶度的MCM－41中孔SiO2分子筛，并提高了其收率；以TG－DTA结果为基础，对分子筛脱模板剂的过程进行了优化，同时以XRD对合成物系中CPBr；TEOSHCl，H2O相对含量对MCM－41分子筛晶相结构的影响以及该结构的形成过程进行了分析，发现MCM－41结构沿S＋X-I 路径的形成经过了Lamellar→Hexagonal相转移历程.     

NSAID naproxen in mesoporous matrix MCM-41: drug uptake and release properties

Hexagonally ordered mesoporous silica material MCM-41 (S_BET?=?1090?m²/g, pore size?=?31.2 ?) was synthesized and modified by 3-aminopropyl ligands. The differences in an uptake and subsequent release of anti-inflammatory drug naproxen from unmodified and amino modified MCM-41 samples were studied. The prepared materials were characterized by high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM), nitrogen adsorption/desorption, Fourier-Transform Infrared Spectroscopy (FT-IR), Small-angle X-ray scattering (SAXS), thermoanalytical methods (TG/DTA) and elemental analysis. The amount of the drug released was monitored with thin layer chromatography (TLC) with densitometric detection in defined time intervals. The amounts of the released naproxen from mesoporous silica MCM-41/napro and amine-modified silica sample A-MCM-41/napro were 95 and 90% of naproxen after 72?h. In this study we compare the differences of release profiles from mesoporous silica MCM-41 and mesoporous silica SBA-15.     

Cu修饰的MCM-41的合成、表征及对芳烃羟化反应催化作用的研究

利用MCM-41形成过程中协同自组装的特点,在合成过程中引入Cu(NH₃)₄²⁺,制备出过渡金属表面修饰的纯硅介孔分子筛Cu-MCM-41,采用XRD,ICP,ESR,N₂吸附等手段确定Cu处于MCM-41的表面,取代了端羟基中氢的位置,与骨架桥氧和硅羟基中的氧配位.利用苯酚羟化反应为探针,考察了Cu-MCM-41的催化活性.结果表明,Cu-MCM-41具有很高的苯酚羟化活性,与TS-1分子筛的催化效果相当,对萘酚的羟化活性也较高.     

Cu修饰的MCM—41的合成,表征及对芳烃羟化反应催化作？…

利用ＭＣＭ－４１形成过程中协同自组装特点,在合成过程中引入Ｃｕ（ＮＨ３）４＾２＋,制备出过渡金属表面修饰的纯硅介孔分子筛Ｃｕ－ＭＣＭ－４１,采用ＸＲＤ,ＩＣＰ,ＥＳＲ,Ｎ２吸附等手段确定Ｃｕ处于ＭＣＭ－４１的表面,取代了端羟基中氢的位置,与骨架桥氧和硅羟基中的氧配位,利用苯酚羟化反应为探针,考察了Ｃｕ－ＭＣＭ－４１的催化活性。结果表明,Ｃｕ－ＭＣＭ－４１具有很高的苯酚羟化活性,与ＴＳ－１分子筛的催     

Influence of cross profile of PE fibers on thermal properties of materials

Molecular sieves MCM-41 were synthesized from rice husk ash (RHA) as alternative sources of silica, called RHA MCM-41. The material was synthesized by a hydrothermal method from a gel with the molar composition 1.00 CTMABr:4.00 SiO₂:1.00 Na₂O:200.00 H₂O at 100 °C for 120 h with pH correction. The cetyltrimethylammonium bromide (CTMABr) was used as a structure template. The material was characterized by X-ray powder diffraction, FTIR, TG/DTG, and surface area determination by the BET method. The kinetics models proposed by Ozawa, Flynn–Wall, and Vyazovkin were used to determine the apparent activation energy for CTMA⁺ species decomposition from the pores of MCM-41 material. The results were compared with those obtained from the MCM-41 synthesized with silica gel. The synthesized material had specific surface area, size, and pore volume as specified by mesoporous materials developed from conventional sources of silica.     

High enantioselectivity in the asymmetric hydrogenation of ketones by a supported Pt nanocatalyst on a mesoporous modified MCM-41 support

Catalysts containing metal nanotubes were prepared by the adsorption of platinum metal nano‐tubes onto functionalized and modified silica surfaces (MCM‐41 and fumed silica). (3‐Chloropro‐pyl)trimethoxysilane and cinchonidine were used for functionalization and modification, respec‐tively. Potassium chloroplatinate was used as the metal precursor to impregnate platinum metal nanotubes on the pretreated functionalized and modified silica surfaces. The solid catalysts were characterized by ESEM, TEM, EDAX, and XPS. The MCM‐41 supported platinum nanotube catalyst showed>98%to~100%enantioselectivity towards the hydrogenation of a range of pharmaceuti‐cally important chemicals such as methyl pyruvate, ethyl pyruvate, and acetophenone with nearly full conversion.     

介孔修饰MCM-41负载Pt纳米催化剂高对映选择性催化酮不对称加氢(英文)

Catalysts containing metal nanotubes were prepared by the adsorption of platinum metal nano-tubes onto functionalized and modified silica surfaces(MCM-41 and fumed silica).(3- Chloropro-pyl)trimethoxysilane and cinchonidine were used for functionalization and modification, respec-tively. Potassium chloroplatinate was used as the metal precursor to impregnate platinum metal nanotubes on the pretreated functionalized and modified silica surfaces. The solid catalysts were characterized by ESEM, TEM, EDAX, and XPS. The MCM-41 supported platinum nanotube catalyst showed 98% to ~100% enantioselectivity towards the hydrogenation of a range of pharmaceuti-cally important chemicals such as methyl pyruvate, ethyl pyruvate, and acetophenone with nearly full conversion.     

Influence of the pore structure of MCM-41 and SBA-15 silica fibers on atomic layer chemical vapor deposition of cobalt carbonyl

Mesoporous high surface area MCM-41 and SBA-15 type silica materials with fibrous morphology were synthesized and used as support materials for the ALCVD (atomic layer chemical vapor deposition) preparation of Co/MCM-41 and Co/SBA-15 catalysts. Co/MCM-41 and Co/SBA-15 catalysts were prepared by deposition of Co2(CO)8 from the gas phase onto the surfaces of preheated support materials in a fluidized bed reactor. For both silica materials, two different kinds of preparation methods, direct deposition and a pulse deposition method, were used. Pure silica supports as well as supported cobalt catalysts were characterized by various spectroscopic (IR) and analytical (X-ray diffraction, Brunauer-Emmett-Teller, elemental analysis) methods. MCM-41 and SBA-15 fibers showed considerable ability to adsorb Co2(CO)8 from the gas phase. For MCM-41 and SBA-15 silicas, cobalt loadings of 13.7 and 12.1 wt % were obtained using the direct deposition method. The cobalt loadings increased to 23.0 and 20.7 wt % for MCM-41 and SBA-15 silicas, respectively, when the pulse deposition method was used. The reduction behavior of silica-supported cobalt catalysts was found to depend on the catalyst preparation method and on the mesoporous structure of the support material. Almost identical reduction properties of SBA-15-supported catalysts prepared by different deposition methods are explained by the structural properties of the mesoporous support and, in particular, by the chemical structure of the inner surfaces and walls of the mesopores. Pulse O2/H2 chemisorption experiments showed catalytically promising redox properties and surface stability of the prepared MCM-41- and SBA-15-supported cobalt catalysts.