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采用溶胶-凝胶法,以正硅酸乙酯为硅源、十六烷基三甲基溴化铵(CTAB)为模板,在碱性条件下合成了尺寸均匀、形状规则的花状形貌的介孔状二氧化硅微球。基于二氧化硅花球特殊的表面褶皱和内部的介孔孔道,将其作为载体负载模型药物布洛芬,探究其药物缓释性能。结果表明,所制备的介孔二氧化硅花球对布洛芬模型药物的负载量为701.63 mg·g~(-1),明显高于传统药物载体材料。此外,对介孔二氧化硅/布洛芬复合粒子进行缓释实验研究,发现10 h后布洛芬的释放量为74.60%,表明其具有较好的药物缓释性能。 相似文献
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利用紫外光引发过硫酸钠产生的羟基自由基替代无机强酸,在中性条件下水解正硅酸四乙酯,一步绿色合成了铜、铁共掺杂的SBA-15有序介孔二氧化硅材料。采用XRD、SEM、TEM、EDS能谱以及物理吸附(N2)等表征手段对所得介孔二氧化硅材料进行了系统表征分析。结果表明:成功合成了纤维状的Fe、Cu共掺杂SBA-15介孔氧化硅材料,该材料呈现出有序的介孔结构,其中Fe∶Cu∶Si原子比约为1∶3∶58;随着Fe、Cu掺杂量增加,Fe-Cu-SBA-15介孔氧化硅材料的比表面积先增大后减小,介孔孔径逐渐减小。 相似文献
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介孔材料由于具有比表面积和孔体积较大、孔径均一、纳米尺寸可调、二氧化硅无生理毒性、热稳定性较好等一系列特点而引起了人们广泛的兴趣和关注.控制介孔二氧化硅的形貌和尺寸可以拓展介孔二氧化硅的应用,尤其是开发介孔二氧化硅在生物医学、 相似文献
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以硅酸钠为硅源,硫酸为酸化剂,聚乙二醇为模板剂,利用均相反应器水热法制备了介孔二氧化硅微球.考察硅酸钠、硫酸、聚乙二醇的浓度及聚乙二醇聚合度对产物形貌和材料表面特性的影响,研究了介孔二氧化硅微球的形成机理.运用XRD,FT-IR,XRF,SEM,BET等手段对产品进行表征.从表征结果可以看出,所制备的介孔二氧化硅微球球形度良好,粒径分布比较均匀,纯度高,比表面在92~577 m2/g、孔体积在0.141~1.141 cm3/g范围内可调控.通过TEM对聚乙二醇胶束的研究得到介孔二氧化硅微球的形成机理. 相似文献
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以长碳链阳离子表面活性剂如十六烷基三甲基溴化铵为模板,可制得高度有序的介孔二氧化硅材料,而碳链较短的表面活性剂如十二烷基三甲基溴化铵,由于其表面活性较差,以其为模板难以制得有序介孔二氧化硅材料.以十二烷基三甲基溴化铵为模板剂,考察了不同硅源、碱源以及pH值对介孔材料结构的影响,采用XRD、FTIR、SEM、HRTEM和N2物理吸附等手段分别对产物的晶体结构、织构性质、形貌和孔道结构进行表征.结果 表明,以正硅酸乙酯为硅源,在有机碱四甲基氢氧化铵存在下,以十二烷基三甲基溴化铵为模板,制得了具有规整六方结构的高度有序介孔二氧化硅材料,其孔径和晶胞常数分别为2.25 nm和3.72 nm. 相似文献
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《Ceramics International》2017,43(2):2174-2181
This work reports the controllable preparation of a unique kind of hierarchically mesoporous silica (HMS) fibers with bimodal porosities based on a simple TEOS/P123/HCl(aq.) templating system via the partitioned cooperative self-assembly (PCSA) process. Experimental results show that the formation of hierarchical mesostructures, especially the 2nd mode porous structure, depends on the interval time pertaining to the PCSA process. Synthetic conditions, including the interval time, temperature and stirring, are all found to be important in the evolution of fiber particle morphology. Moreover, such HMS fibers can be used as building units to prepare mesoporous silica monoliths with hierarchical trimodal pore systems via a simple gel-casting method, with additional (the 3rd modal) macropores originating from the packing of micron-sized HMS fibers. Such materials might further expand the application of both HMS fibers and HMS monoliths in various fields. 相似文献
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Preparation of mesoporous silica fiber matrix for VOC removal 总被引:3,自引:0,他引:3
Young-Hwan Chu Hyun-Jong Kim Keun-Young Song Yong-Gun Shul Kyeong-Taek Jung Kangtaek Lee Moon-Hee Han 《Catalysis Today》2002,74(3-4):249-256
A novel method for the preparation of the mesoporous silica fiber matrix was introduced for a removal of volatile organic compounds (VOCs). Paper making technology was applied to make a sheet of mesoporous silica fiber matrix. Reinforcing the mesoporous silica fiber with the ceramic fibers (50 wt.%) increased the mechanical strength of the matrix. Mesoporous silica fibers using TMOS (tetramethoxysilane) as a silica source and CTAC (cetyltrimethyl-ammoniumchloride) as a surfactant were drawn by the spinning method. The spinning process increased both the crystallinity and the fraction of mesopores (1.9 nm) of the fiber. As the spinning rate was increased both the crystallinity and the specific area of the mesoporous silica fiber increased, but the diameter of fiber decreased. We could control the size and morphology of mesoporous silica fiber matrix by changing the shape of substrates. This leads to easy fabrication of honeycomb-structured adsorbent which can be used for the VOC removal. 相似文献
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Hirobumi Shibata Taku Ogura Keishi Nishio Hideki Sakai Masahiko Abe Kazuaki Hashimoto Mutsuyoshi Matsumoto 《SILICON》2011,3(3):139-143
Large-pore mesoporous silica particles were synthesized through a solvent evaporation process using hydrophobic fumed silica
particles and tetraethyl orthosilicate (TEOS) as silica sources. The solvent evaporation of an ethanol solution of fumed silica
particles, TEOS, HCl and triblock copolymer (F127) resulted in mesoporous silica particles with pores with sizes of about
7 nm. In addition, the interplanar spacing of the mesoporous silica particles can be controlled by changing the solvent evaporation
temperatures. 相似文献
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Hsien-Ming Kao Tzu-Yi Shen Jyun-Da Wu Lung-Ping Lee 《Microporous and mesoporous materials》2008,110(2-3):461-471
Well-ordered cubic mesoporous silicas SBA-1 functionalized with thiol groups have been synthesized via co-condensation of tetraethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) templated by cetyltriethylammonium bromide (CTEABr) under strongly acidic conditions. Various synthesis parameters such as HCl concentration, synthesis temperature, and time for hydrothermal treatment were systematically investigated as a function of MPTMS contents. The materials thus obtained were characterized by a variety of techniques including powder X-ray diffraction (XRD), solid-state 13C and 29Si NMR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and nitrogen sorption measurements. Direct evidence of the presence of chemically attached thiol moieties was provided by solid-state 29Si and 13C NMR spectroscopy. A high degree of structural ordering was still retained when MPTMS loading was incorporated up to 20 mol% in the synthesis mixture. Increasing the synthesis temperature and the time for the hydrothermal treatment not only increased the degree of framework cross-linking, but also did not lead to the undesirable phase transformation as often observed in the conventional synthesis of pure silica SBA-1. SEM results reveal that the morphology of thiol-functionalized SBA-1 depends on the HCl concentration used in the synthesis. The sample prepared with a low acid concentration exhibits a highly isotropic morphology with more facets than that of pure silica SBA-1, whereas it changes to a spherical shape as the acid concentration is increased. The maximum content of the attached thiol group (–SH) in the mesoporous framework is 2.39 mmol/g. The thiol-functionalized SBA-1 mesoporous materials are efficient Hg2+ adsorbents. 相似文献
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Hatem M Alsyouri Malyuba A Abu-Daabes Ayah Alassali Jerry YS Lin 《Nanoscale research letters》2013,8(1):484
Acidic interfacial growth can provide a number of industrially important mesoporous silica morphologies including fibers, spheres, and other rich shapes. Studying the reaction chemistry under quiescent (no mixing) conditions is important for understanding and for the production of the desired shapes. The focus of this work is to understand the effect of a number of previously untested conditions: acid type (HCl, HNO3, and H2SO4), acid content, silica precursor type (TBOS and TEOS), and surfactant type (CTAB, Tween 20, and Tween 80) on the shape and structure of products formed under quiescent two-phase interfacial configuration. Results show that the quiescent growth is typically slow due to the absence of mixing. The whole process of product formation and pore structuring becomes limited by the slow interfacial diffusion of silica source. TBOS-CTAB-HCl was the typical combination to produce fibers with high order in the interfacial region. The use of other acids (HNO3 and H2SO4), a less hydrophobic silica source (TEOS), and/or a neutral surfactant (Tweens) facilitate diffusion and homogenous supply of silica source into the bulk phase and give spheres and gyroids with low mesoporous order. The results suggest two distinct regions for silica growth (interfacial region and bulk region) in which the rate of solvent evaporation and local concentration affect the speed and dimension of growth. A combined mechanism for the interfacial bulk growth of mesoporous silica under quiescent conditions is proposed. 相似文献
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In a neutral buffer system (Tris–HCl), the sheet-like mesoporous silica SBA-15 with regular hexagonal array was synthesized
in the presence of the triblock copolymer P123 and the organic salt Na2EDTA. The small angle X-ray scattering, N2 adsorption–desorption, SEM, and TEM techniques were used to investigate the topology and morphology of the synthesized mesoporous
silica, which shows a well-ordered hexagonal mesostructure and a sheet-like morphology. The mesopore channels in the synthesized
material are perpendicular to the sheet plane. The strategy via the addition of the organic salt Na2EDTA provides an alternative to synthesize SBA-15 with a sheet-like morphology under mild conditions. 相似文献
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Electroblowing and sol–gel reaction were combined to prepare mesoporous silica fibers. Poly(methyl methacrylate) (PMMA), a simple commercial polymer with weak hydrogen bonding to silica, was demonstrated to be valuable in improving the electrospinnability and as a porogenic agent. Compared with that in electrospinning, the jet stream in electroblowing was more stable and the resultant fibers were more uniform. The electroblown fibers were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption and desorption isotherms. The phase separation behavior and mechanism for the formation of the amorphous mesoporous structure were discussed. Although there was no covalent bonding between PMMA and silica, macrophase separation was completely prevented in the electroblown fibers and the pore size in the calcined silica fibers ranged from 10 to 20 nm. However, the previously reported electrospun silica fibers, in which surfactants or polymers with strong hydrogen or covalent bonding to silanol groups were used as structure directing agents, had average pore sizes below 10 nm. The present study offers a facile method for the preparation of highly mesoporous silica fibers with large mesopores. 相似文献
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Preparation of Spherical Hexagonal Mesoporous Silica 总被引:1,自引:0,他引:1
A series of hexagonal mesoporous silica (HMS) have been synthesized by the neutral assemble pathway in water-alcohol cosolvent systems, using dodecylamine (DDA) and tetraethyl orthosilicate (TEOS) as the starting materials. These materials were characterized with powder X-ray diffraction, nitrogen sorption measurement, differential thermal analysis, and transmission electron microscopy. The XRD patterns of these samples exhibited a strong intense reflection at low angle, suggesting the excellent mesostructures of the samples. The particle size of HMS decreased and the morphology of HMS exhibited high textural porosity as the HMS was prepared with high addition rate of TEOS. The particle size of HMS prepared without aging was smaller than that aged for 18 h, due to the reaction time of TEOS was not enough to form complete particles. Addition of NaCl and HCl hindered the formation of HMS mesoporous structure. In contrast, addition of 1-butanol did not affect the formation of HMS mesoporous structure. The sphereical HMS silica with uniform size has been synthesized by adjusting DDA and TEOS concentrations. The shape of HMS became larger and more spherical as the concentrate on of DDA decreased. The stirring rate of the reaction mixture had no effect on either the shape or the size of the spheroid HMS silicas. However, the particles started to crack at higher stirring rates. 相似文献
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Ji Sun Im Jeen-Seok Jang Young-Seak Lee 《Journal of Industrial and Engineering Chemistry》2009,15(6):914-918
In our study, mesoporous carbon fibers were prepared by using electrospinning and physical activation. In order to develop mesoporous structure, silica was used as a physical activation agent due to meso-size of particle. The diameter of activated carbon fibers increased and surface became rougher after physical activation. Textural properties of carbon fibers were evaluated by using surface pore structure analysis apparatus. The specific surface area increased 12 times and total pore volume increased about 57 times through physical activation using silica. The development of mesoporous structure was confirmed by pore size distribution and fraction of micropore volume. From the DFT pore size distribution, it is sure that broad meso-sized porous carbon fibers were obtained from physical activation in our experiment. The fact that fractions of micropore volume are too low showing less than 2% by the results of total pore volume and HK pore volume concedes that silica activated CFs are pretty mesoporous. Eventually activated carbon fibers having broad meso-sized pores were obtained successfully. 相似文献