Thin Film of Mesoporous MCM-41 Grown on Indium-Tin-Oxide Glass Substrate

From a basic solution containing celyltrimethylammonium cations as the template, thin film of mesoporous MCM-41 has been grown on the surface of a pre-treated indium-tin-oxide conducting glass substrate. The channel axis of the film is oriented parallel with the surface plane of the substrate, and the film is stable after careful removal of template in vacuum.

Microwave radiation one-pot synthesis of chloropropyl-functionalized mesoporous MCM-41

Chloropropyl-functionalized mesoporous MCM-41(MCM-41-(CH2)3Cl) was synthesized in alkaline medium by the microwave radiation one-pot method, using cetyltrimethy-lammoniumbromide (CTAB) as novel template, tetraethoxysilane (TEOS) as silica source, and chloropropyltriethoxysilane (ClPTES) as the coupling agent. The microstructure of MCM-41-(CH2)3Cl was characterized by the means of X-ray diffraction (XRD), nitrogen absorption-desorption, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that a successful synthesis of MCM-41-(CH2)3Cl with well structure is obtained. The optimal microwave power is 120 W and the best microwave time is 50 min. The dosage of chloropropyltriethoxysilane on the structure of chloropropyl-functionalized MCM-41 was also investigated. It is found that the chloropropyltriethoxysilane volume between 0.8 mL and 1.6 mL is favorable for the formation of highly ordered MCM-41-(CH2)3Cl mesostructure.

Removal of Fluoride from Water Using Mesoporous MCM-41: An Optimization Approach Using Response Surface Methodology (RSM)

Fluoride above 1.5 mg·L-1 is injurious to health. Removal of fluoride from water using mesoporous MCM-41 as a strong adsorbent material has been attempted. Characterization using transmission electron microscopic study of calcined MCM-41 showed the regular hexagonal array of mesoporous channels with an average size of 20 nm and the surface area (BET study) of 1306.96 m2·g-1. The average pore size of the particles was found to be 14.21 nm. A study on the effect of contact time on the removal of fluoride revealed that more than 85% uptake of fluoride onto MCM-41 was achieved at a contact time of 120 min. From the Langmuir adsorption study, the maximum sorption capacity of fluoride was found to be 63.05 mg/g at 301 K. From the thermodynamic study, the +ΔHo value of 2.29 kJ·mol-1 indicated the endothermic nature of the removal process. Application of Response Surface Model suggested that 77.88% of fluoride removal can be achieved at fluoride concentration of 10 mg·L-1, pH (6.3), and contact time of 120 min.

Large Pore Mesoporous MCM-41 Templated from Cetyltriethylammonium Bromide

Following hydrothermal synthesis process, MCM-41 was synthesized by using cetyltriethylammonium bromide as templating agent. The experimental results showed that MCM-41 with pore diameter in the range of 4-7 nm can be obtained by adjusting nsurf/nsi. It was proved that cetyltriethylammonium bromide is an effective templating agent for increasing pore diameter of molecular sieve MCM-41.

Effect of inductively coupled plasma surface treatment on silica gel and mesoporous MCM-41 particles

Silica gel and MCM-41 synthesized mesoporous materials were treated with either oxygen（O_2）,hexamethyldisiloxane（HMDSO） and organic vapors like ethanol（Et OH）,and acrylonitrile（AN）inductive plasma.The radiofrequency power for the modification was fixed to 120 W and30 min,assuring a high degree of organic ionization energy in the plasma.The surface properties were studied by infrared spectroscopy（FTIR）,scanning electron microscopy,x-ray photoelectron spectroscopy and dynamic light scattering technique was used for characterizing size distributions.When the silica and MCM-41 particles were modified by AN and HMDSO plasma gases,the surface morphology of the particles was changed,presenting another color,size or shape.In contrast,the treatments of oxygen and Et OH did not affect the surface morphology of both particles,but increased the oxygen content at the surface bigger than the AN and HMDSO plasma treatments.In this study,we investigated the influence of different plasma treatments on changes in morphology and the chemical composition of the modified particles which render them a possible new adsorbent for utilization in sorptive extraction techniques for polar compounds.

Preparation and Spectroscopic Properties of Tris (2, 2′-bipyridine)ruthenium(Ⅱ)Loaded in Siliceous Mesoporous MCM-41

[Ru (bpy)_3]^(2+)/MCM-41 composite material obtained by loading tris(2, 2' - bipyridine)ruthenium(Ⅱ) ([Ru (bpy)_3]^(2+) ) in siliceous mesoporous MCM-41 was characterized by X-ray powder diffraction, UV-Vis absorption and emission spectroscopies. The absorption spectrum of [Ru(bpy)_3]^(2+) /MCM-41 is similar to that of [Ru (bpy)_3]^(2+) aqueous solution, whereas its emission spectrum exhibits hypsochromic shift compared to the solution spectrum. On the other hand, the peak position of the emission spectrum of [Ru(bpy)_3]^(2+)/MCM-41 shifts towards longer wavelength when the loading amount increases.

在极浓体系中合成中孔(MESOPOROUS)Si-MCM-41分子筛及其性质

由无定形凝胶体系Ｎａ２Ｏ－ＳｉＯ２－ＣＴＡＢ（十六烷基三甲基溴化铵）－Ｈ２Ｏ，在控制Ｈ２Ｏ／Ｓｉ≤５．０的极浓条件下，研究了Ｓｉ－ＭＣＭ－４１分子筛的合成条件。在Ｈ２Ｏ／Ｓｉ＝１．０－５．０，ＣＴＡＢ／Ｓｉ＝０．０１２５－０．１２５；Ｎａ／Ｓｉ＝０．０５－０．１５时，均可合成Ｓｉ－ＭＣＭ－４１分子筛。该体系特点是ＣＴＡＢ消耗明显降低。ＸＲＤ、ＳＥＭ、ＴＧ－ＤＴＡ和Ｎ２吸附性质表征了合成的ＭＣＭ－４１分子筛，证明本法合成产物具有典型的ＭＣＭ－４１分子筛特性。

复合材料MnO_(2)/MCM-41对放射性废水中Sr^(2+)的去除

采用一锅法制备MnO_(2)/MCM-41复合材料,探究其对放射性废水中Sr^(2+)的去除。通过SEM、BET、FT-IR对复合材料进行了表征。探究MnO_(2)和MCM-41的质量比、pH、吸附时间、竞争离子效应等参数对其吸附性能的影响。结果表明,复合材料能迅速吸附水中Sr^(2+),并在120 min达到吸附平衡,最大吸附容量为85.46 mg/g。MnO_(2)和MCM-41的质量比为4∶1时复合材料具有最高的吸附容量,在pH为4~9范围内复合材料具有较高的吸附性能,此外复合材料在Na^(+)、K^(+)、Mg^(2+)、Ca^(2+)存在的情况下依然保持良好的吸附容量,抑制吸附能力遵循Na^(+)<K^(+)<Mg^(2+)<Ca^(2+)的排序。吸附动力学分析伪二级模型比伪一级模型更能拟合吸附数据,说明化学吸附在吸附过程中占主导地位。所制备的MnO_(2)/MCM-41新型复合材料用于去除放射性废水中的Sr^(2+)具有吸附迅速、吸附容量大、选择性强、能够大规模制备等优点,这使得其有望在含Sr^(2+)放射性废水处理领域发挥重要作用。

Synthesis of Ln-doped MCM-41 mesoporous materials and their catalytic performance in oxidation of styrene

Using cetyl-trimethyl-ammonium bromide （CTMAB） as the template agent and tetraethylorthosilicate （TEOS） as the silica source, the MCM-41 mesoporous materials were synthesized with La or Ce incorporated in the framework under hydrothermal conditions. The structure and the state of La or Ce were investigated through the analyses of XRD, nitrogen adsorption-desorption, FT-IR, and UV-Vis. XRD and N2 adsorption-desorption results showed that Ln-MCM-41 exhibited the loss of the lattice ordering of the MCM-41 construct, and larger unit cell parameter and pore diameter than pure silica MCM-41. The FT-IR and UV-Vis results indicated the presence of isolated tetra-coordinated La or Ce ions in the framework and other Ln species dispersed highly on the Ln-MCM-41 surface simultaneously. Furthermore, their catalytic behaviors in the oxidation of styrene were studied using H2O2 as the oxidant. The La-MCM-41 catalysts exhibited high reactivity and the reactivity increased with the increase of the La content in the La-MCM-41 samples. On the contrary, Ce-MCM-41 catalysts showed low reactivity in the oxidation of styrene and the conversion of styrene decreased with the increase of the Ce content in the Ce-MCM-41 samples.

Synthesis and Characterization of Mesoporous Materials MCM-41 Incorporated by Yttrium, Neodymium and Samarium

Using cetyl-trimethyl-ammonium bromide （CTMAB） as template and tetraethylortho-silicate （TEOS） as silica source, the MCM-41 mesoporous materials incorporated in framework by Y, Nd and Sm were synthesized by hydrothermal synthesis method. The structure, morphology of materials and the state of Y, Nd, Sm in materials were investigated by means of XRD, nitrogen adsorption-desorption, SEM, IR spectrometry, TG-DTA. The XRD results indicate that the samples possess the mesoporous MCM-41 structures with ordered hexagonal arrangements. Y, Nd and Sm ions can get into the framework of mesoporous materials. Nitrogen adsorption desorption isotherms show that the samples have typical mesopores characteristics. SEM micrographs reveal that incorporated sampies show a spherical morphology and the diameters are averagely 0. l0 to 0.15 μm. In IR spectrum of samples, there are the feature adsorption peaks about Si-O-Ln（Ln=Y, Sm, Nd）at 960-985 cm^-1, which affirm that Y, Nd, Sm ions locate in the framework of several mesoporous materials. Results from TG-DTA analysis suggest that two different template sorption sites exist in the framework of YMCM-41, SmMCM-41, NdMCM-41, which powerfully proves that the presence of Y, Nd and Sm in Si framework of the materials.

Preparation and Properties of Zirconium Hydrideon the surface of MCM-41 Mesoporous Molecular Sieves

Zirconium monohydride bonded to the framework oxygen of MCM-41 surface was prepared by the reaction of tetraneopentyl zirconium with MCM-41 surface hydroxyl groups, followed by the hydrogenolysis of the resulted product. The surface hydride was characterized by using infrared spectroscopy, solid-state NMR, elemental analysis, gas-phase chromatography and chemical probing reaction. It was shown that this surface species is stable below 150 ’C and can catalytically crack alkanes into methane and ethane at 100 .

Synthesis and Characterization of Mesoporous Silicon Oxynitride MCM-41 with High Nitrogen Content

Mesoporous silicon oxynitrides MCM-41 were synthesized successfully. The resulting materials not only have high nitrogen contents and good structural characteristics of MCM-41 (high surface area, narrow pore size distribution and good order), but also are amorphous. The composition and structure of the materials were investigated by CNH element analysis, XPS, Si MAS NMR, XRD, HRTEM and N-2 sorption, respectively. Mesoporous silicon oxynitrides MCM-41 with a high nitrogen content are still non-crystal (amorphous).

Formation at low surfactant concentrations and characterization of mesoporous MCM-41

At low concentrations of cetyltrimethylammonium bromide,all silica-based mesoporous materials with hexagonal phase have been synthesized via interactions between self-assembled surfactant molecule aggregates and aniomc silicate polymers.The resulting materials are characterized by XRD,FT-IR,solid state 29Si MAS NMR,thermal analysis and N2 adsorption-desorption measurements.After soluble ions are removed,the interactors between surfactant micelles and silicate polymers are reorganized and then form mesostructures 1 he hexagonal framework is sonsistent with amorphous silica gel.The structures of materials depend on the synthesis conditions Hydrothermal process improves the interactions between molecules and increases the degree of framework silicon atom polymerization The.surface area and the mesopore volume of the material prepared at 100℃ increase by 87% and 71 %,respectively,compared with those obtained at room temperature.

A catalysis study of mesoporous MCM-41 supported Schiff base and CuSO_4·5H_2O in a highly regioselective synthesis of 4-thiazolidinone derivatives from cyclocondensation of mercaptoacetic acid

Mesoporous MCM-41 supported Schiff base and Cu SO4· 5H2 O shows high catalytic activity in the cyclocondensation of mercaptoacetic acid with imines（or aldehydes and amines） to afford pharmaceutically important thiazolidinone derivatives. The catalytic reactions involving twocomponents or three-components afforded the desired product in high yields（up to 98% and 99%）.Moreover, the catalyst works well with respect to recyclability, giving the product in 85% and 83% yields after recycling six times.

Synthesis and Characterization of Mesoporous Materials MCM-41 Incorporated by Yttrium, Neodymium and Samarium

Using cetyl-trimethyl-ammonium bromide （CTMAB） as template agent and tetraethylorthosilicate （TEOS） as silica Source, the MCM-41 mesoporous materials were synthesized with Y, Nd and Sm incorporated in the framework under hydrothermal conditions. The structure and the micro-morphology of the materials and the state of Y, Nd and Sm were investigated through the analyses of XRD, nitrogen adsorption-desorption isotherm, SEM, IR and TG-DTA. The XRD resuits indicate that the synthetic samples are of typical structure of mesoporous MCM-41 with ordered hexagonal arrangements, and Y, Nd and Sm can be incorporated into the framework of these mesoporous materials. Nitrogen adsorption-desorption isotherms show that the samples possess the typical mesopores character. SEM micrographs reveal that the incorporated samples show a well-defined spherical morphology with the diameter ranging 0.10 - 0.15μm. The occurrence of two different template sorption sites in the framework as revealed by TG-DTA analysis further suggests the presence of Y, Nd and Sm in siliceous framework.

Synthesis of Mesoporous Molecular Sieve MCM-41 in Extremely Dense System

Mesoporous molecular sieve MCM-41 has been synthesized in the extremely dense system (with H2O/Si<10) and characterized by XRD, N-2 adsorption isotherm as well as probe reactions of cracking of cumene and isomerization of o-xylene.

CoFe_(2)O_(4)/MCM-41催化剂的制备及其光催化降解亚甲基蓝性能

采用水热法将纳米CoFe_(2)O_(4)与MCM-41介孔分子筛复合,制备了CoFe_(2)O_(4)/MCM-41光催化剂。通过TG-DTA,XRD,SEM,N2吸附-脱吸等方法对制备的催化剂进行表征,并以亚甲基蓝染料废水为研究对象,考察了催化剂光催化降解亚甲基蓝的性能。实验结果表明,CoFe_(2)O_(4)/MCM-41催化剂仍具有介孔材料的孔道结构,CoFe_(2)O_(4)纳米粒子在分子筛孔道或表面均匀分散,呈现尖晶石结构,使CoFe_(2)O_(4)/MCM-41复合催化剂具有良好的催化活性。CoFe_(2)O_(4)/MCM-41复合催化剂(Co与Si摩尔比为1∶1)在初始染料质量浓度为10 mg/L、溶液pH=7、可见光照射的条件下,2 h内对亚甲基蓝降解率达到98.3%,降解速率符合一级反应动力学。CoFe_(2)O_(4)/MCM-41重复使用5次后,亚甲基蓝的降解率仍可达到86.6%。

ZnO/MCM-41煤气脱硫剂脱硫过程COS生成行为及Co助剂的影响

在金属氧化物脱硫过程中,普遍存在部分硫化氢(H_(2)S)转化为羰基硫(COS)的现象,而COS具有与H_(2)S相似的危害性,且脱除难度更大。采用溶胶凝胶法制备了具有良好脱硫性能的ZnO/MCM-41煤气脱硫剂(以下简称“脱硫剂”),在固定床装置上探究了COS在煤气脱硫过程中的生成行为,并提出采用Co助剂对脱硫剂进行改性的方法来抑制COS的形成,然后结合XRD和XPS等表征手段对脱硫剂的物相组成和结构进行分析。通过研究不同脱硫气氛中COS的生成行为,发现COS主要来源于CO/CO_(2)与H_(2)S之间的反应,且ZnS对CO_(2)与H_(2)S之间的反应起催化作用;CO-H_(2)S反应与CO_(2)-H_(2)S反应之间不存在协同作用;H_(2)对COS的形成有抑制作用。向脱硫剂中添加Co质量分数为1%、3%和5%的Co助剂时,分别使脱硫过程中的COS产生量降低了69.0%、94.9%和98.4%,这主要与Co助剂对COS加氢反应的催化作用有关。此外,添加Co质量分数为3%的Co助剂使脱硫剂的硫容提升了0.32%。

复合材料TiO_(2)/MCM-41光催化降解四环素的研究

以粉煤灰为主要原料,采用水热合成法制备粉煤灰基MCM-41分子筛,并以此为载体,制备不同TiO_(2)质量分数的TiO_(2)/MCM-41复合材料,采用XRD、XPS、SEM和UV-Vis DRS等对材料进行表征,结果表明,MCM-41分子筛的介孔孔道为TiO_(2)生长提供了良好环境并有效阻止了TiO_(2)晶粒的团聚,使之形成均匀的晶粒,减小粒径长度产生吸收带蓝移。将其作为催化剂用于对四环素(TC)的催化降解研究,考察了催化剂投加量、TC初始质量浓度及初始pH等对光催化反应的影响。结果表明,TiO_(2)质量分数为32%的催化剂在pH为6.8、催化剂投加量为0.2 g/L和TC初始质量浓度为30 mg/L时的催化效果最优,TC的降解过程符合拟二级动力学方程。