共查询到20条相似文献,搜索用时 31 毫秒
1.
Taissire BenamorLaure Michelin Bénédicte Lebeau Claire Marichal 《Microporous and mesoporous materials》2012,147(1):334-342
A new rapid calcination method has been used to completely remove the organic template from SBA-15 ordered mesoporous silica, and to preserve a high number of silanol in these materials. This calcination method provided by an induction furnace was found to considerably reduce the calcination time and therefore the energy consumption associated. Moreover, adjustment of both calcination temperature and duration allowed tuning the hydrophobic/hydrophilic balance of the mesoporous SBA-15 silica materials. For comparison, short and long time conventional muffle furnace calcination was performed. The induction calcination was also successfully applied to different type of mesoporous silica materials such as SBA-16 and MCM-41. 相似文献
2.
Hector Iván Meléndez-Ortiz Bertha Puente-Urbina Jesus Alfonso Mercado-Silva Lorena García-Uriostegui 《International Journal of Applied Ceramic Technology》2019,16(4):1533-1543
The dye adsorption performance of four mesoporous silicas with different structure and textural properties, MCM-41, MCM-48, SBA-15 and mesocellular silica foam (MCF), was studied and compared by using toluidine blue O (TBO) as dye model in aqueous solution. These materials were characterized by X-ray diffraction (XRD), small-angle X-ray scattering, nitrogen adsorption-desorption analyses, and transmission electron microscopy (TEM). The effect of some parameters such as adsorbent dosage, contact time, temperature, and pH on the TBO removal in aqueous solution was studied. Results showed that adsorption capacity raised when adsorbent dosage, contact time and pH solution were increased while an increase in temperature decreased the adsorption of TBO. Langmuir, Freundlich and Temkin isotherm models were employed to elucidate the adsorption mechanism while the adsorption rate data were analyzed according to the pseudo-first and second-order kinetic models. Results showed that adsorption of TBO onto MCM-48, SBA-15, and MCF fitted well the Freundlich isotherm model while the kinetic studies showed that adsorption process could be better described by the pseudo-second-order model for all mesoporous silicas. Finally, some solvents were evaluated to carried out dye desorption from the TBO-loaded mesoporous silicas founding that acetic acid was the most efficient. 相似文献
3.
High quality mesoporous materials prepared by supercritical fluid extraction: effect of curing treatment on their structural stability 总被引:1,自引:0,他引:1
Z. Huang L. Huang S.C. Shen C.C. Poh K. Hidajat S. Kawi S.C. Ng 《Microporous and mesoporous materials》2005,80(1-3):157-163
Mesoporous molecular sieves like SBA-1, SBA-3, MCM-41 and MCM-48 are generally synthesized by using a quaternary ammonium surfactant as a structure-directing agent to form a porous silica framework. The used templating agent is conventionally removed for producing mesopores by calcination at high temperature. In this study, supercritical fluid extraction (SFE) has been employed to remove organic templates from these materials. We found that more than 80% of the templating agent can be successfully removed by using this technique. Among these materials, SBA-3 was observed to experience the collapse of mesoporous structures upon the SFE process. Thus, we have proposed pre-SFE thermal aging as a curing treatment method and found that it has significantly improved the mesoporous structural stability of SBA-3. In the meantime, this curing method has lead to these SFE-processed materials with better ordered mesoporous structures, such as SBA-3 having specific surface area as large as 1670 m2/g. 相似文献
4.
Mesoporous silica SBA-15 samples were subjected to microwave heating for 10–40 min at 393 and 443 K after dry-impregnation
with TPAOH (tetrapropylammonium hydroxide) to prepare a mesoporous material with zeolytically ordered pore walls. Physicochemical
properties of the materials prepared were characterized by XRD, N2 adsorption at 77 K, SEM, TEM, UV–vis and FT-IR spectroscopies. These investigations revealed that selective transformation
of amorphous pore walls of SBA-15 to crystalline zeolytic phase is difficult to be achieved and a mixed phase of mesoporous
silica/zeolite composite material was obtained, instead. Microwave heating time, temperature, TPAOH concentration, and hydrothermal
stability of the mesoporous host materials tested (MCM-41, HMS, and SBA-15) were important factors to maintain the mesopore
structure of the host materials during the post-synthetic microwave heating treatment. 相似文献
5.
Yanchen HuZhuangzhi Zhi Qinfu ZhaoChao Wu Peng ZhaoHaitao Jiang Tongying Jiang Siling Wang 《Microporous and mesoporous materials》2012,147(1):94-101
The present work was proposed not only to exploit the potential of 3D cage-like mesoporous silica SBA-16 with a well-defined spherical morphology as a carrier for poorly soluble drugs, but also to compare the drug loading and release properties of 3D cubic SBA-16 with that of classic 2D hexagonal MCM-41. SBA-16 microsphere with highly ordered mesostructures was synthesized by a facile method using block co-polymer F127 as template, cetyltrimethylammonium bromide (CTAB) as co-template and tetraethyl orthosilicate (TEOS) as silica source. Carvedilol (CAR), an antihypertensive agent, was used as a model drug and loaded into mesoporous silica via solvent deposition method at drug-silica ratio of 1:3. In vitro dissolution was performed in both simulated intestinal fluid (SIF, pH 6.8) and simulated gastric fluid (SGF, pH 1.2). Of particular interest was that in SIF both MCM-41 and SBA-16 samples exhibited promoted dissolution profile for CAR as compared to its corresponding crystalline form which exhibited poor dissolution behavior. This dissolution-enhancing effect might be due to the non-crystalline state and increased surface area of confined CAR as well as the hydrophilic nature of silica. In comparison with MCM-41, SBA-16 displayed a more rapid release profile in both SIF and SGF, which may be ascribed to the 3D interconnected pore networks and the highly accessible surface areas. The suitability of the utilization of SBA-16 microsphere as carriers will open new avenues for the formulation of poorly soluble drugs. 相似文献
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以分子筛为载体,采用等体积浸渍法制备Ce/SBA-15、Ce/MCM-41、Ce Co/SBA-15和Ce Co/MCM-41催化剂。用N2吸附-脱附、X射线衍射、扫描电子显微镜、H2程序升温还原、X射线光电子能谱和傅立叶变换红外光谱等对载体和催化剂进行表征,并考察催化剂催化氧化甲苯的活性。结果表明,与载体相比,随着Ce和Co的浸渍,催化剂的比表面积和孔容下降,但仍然保持了载体的有序介孔结构。引入的Ce和Co没有进入分子筛骨架,而是以立方相固溶体形式存在于分子筛表面和孔道中。催化剂催化氧化甲苯活性顺序依次为:Ce Co/SBA-15>Ce Co/MCM-41>Ce/MCM-41>Ce/SBA-15。共浸渍Ce和Co的催化剂活性明显优于只浸渍Ce的催化剂,活性与其还原性能直接相关,Ce Co/SBA-15催化剂具有最低的还原温度和最好的供氧能力,从而表现出最优的催化性能。 相似文献
8.
采用溶剂法和焙烧法制备了SBA-15和MCM-41两类介孔氧化硅,并以此为载体制备固载型三氟甲基磺酸镱(Yb(OTf)3)催化剂。通过小角X射线衍射(SAXD)、氮气吸附/脱附、29Si固体核磁共振光谱(NMR)、透射电子显微镜(TEM)及热重分析(TG)等方法对载体及催化剂进行表征,研究其在葡萄糖制备乳酸反应中的催化性能。结果表明:溶剂法制备的氧化硅表面羟基含量比焙烧法高,负载的磺酸基团和三氟甲基磺酸镱都更多,催化活性更高;SBA-15的平均孔径比MCM-41的大3 nm左右,这使得SBA-15具有更好的传质性能以及Yb(OTf)2-SBA-15具有更好的催化性能。以Yb(OTf)2-SBA-15-S为催化剂,在2 MPa N2压力、190 ℃下反应60 min,乳酸的收率达到42.35%。 相似文献
9.
Synthesis of mesoporous materials SBA-15 and CMK-3 from fly ash and their application for CO2 adsorption 总被引:1,自引:0,他引:1
A supernatant solution of silicate species extracted from coal fly ash in a power plant by alkali fusion was used in acidic
condition to prepare a mesoporous silica SBA-15. The SBA-15 was used as a template for the synthesis of a mesoporous carbon
CMK-3 using sucrose as a carbon source. Characterization of the produced mesoporous materials by XRD, N2 adsorption-desorption, SEM, and TEM confirmed the formation of well-ordered hexagonal mesostructures. Textural properties
were found close to those prepared by pure chemicals. SBA-15 after polyethyleneimine impregnation and CMK-3 were tested for
carbon dioxide adsorption, successfully demonstrating the possibility of recycling the industrial waste product in a power
plant into a useful adsorbent. 相似文献
10.
Chang-Lin Chen Tao Li Soofin Cheng Nanping Xu Chung-Yuan Mou 《Catalysis Letters》2002,78(1-4):223-229
Alumina-promoted sulfated zirconia was supported on mesoporous molecular sieves of pure-silica MCM-41 and SBA-15. The catalysts were prepared by direct impregnation of metal sulfate onto the as-synthesized MCM-41 and SBA-15 materials, followed by solid state dispersion and thermal decomposition. Measurements of XRD and nitrogen adsorption isotherms showed that the structures of resultant materials retain well-ordered pores, even with ZrO2 loading as high as 50 wt%. The characterization results indicated that most of the promoted sulfated zirconia were well dispersed on the internal surface of the ordered mesopores. The catalytic behavior of the alumina-promoted sulfated zirconia supported on mesoporous silica was studied in n-butane isomerization. The supports of mesoporous structures led to high dispersion of sulfated zirconia in the meta-stable tetragonal phase, which was the catalytic active phase. The high performance of alumina-promoted catalysts was ascribed to the sulfur retention by alumina. 相似文献
11.
Sadanobu Sumiya Yuka Kubota Yasunori Oumi Masahiro Sadakane Tsuneji Sano 《Applied Catalysis A: General》2010,372(1):82-89
The calcination and thermal degradation behaviors of surfactants in mesoporous silicas SBA-15 and MCM-41 were investigated by FT-IR, 13C CP/MAS NMR, TG/DTA, and GPC. It was found that carboxylic acid-containing products were generated as active components in the mesopores of SBA-15 and MCM-41 from the triblock copolymer (PEO)20(PPO)70(PEO)20 and cetyltrimethylammonium bromide (CTAB), respectively; the latter materials were used as templates. The carboxylic acid-containing mesoporous silica obtained showed a catalytic activity for hydrolysis of sucrose. The acidity was evaluated by means of NaOH titration. The acidity sensitively depended on both the calcination temperature and the atmosphere; the maximum appeared at 150 °C in air for SBA-15 where the highest activity was observed. However, the product in MCM-41 showed a lower catalytic activity than that in SBA-15. The SBA-15 product was easily leached from the mesopores of SBA-15 into the solution, but the degree of leaching for MCM-41 was considerably smaller than that for SBA-15. 相似文献
12.
Chao Chen Kwang-Seok You Ji-Whan Ahn Wha-Seung Ahn 《Korean Journal of Chemical Engineering》2010,27(3):1010-1014
A supernatant solution of silicate species extracted from bottom ash in a power plant was used to prepare a mesoporous silica
by the synthesis protocol of SBA-15. XRD, N2 adsorption-desorption, and TEM confirmed a disordered mesopore structure. The pore volume and average pore size of the product
were significantly larger than SBA-15 prepared using pure chemicals, and complementary textural mesoporosity was detected.
When the mesoporous silica was tested for carbon dioxide sorption after polyethyleneimine (PEI) impregnation, substantially
higher CO2 sorption capacity (169 mg CO2/g-sorbent) was achieved than that of PEI-impregnated pure SBA-15 under the same test conditions. High CO2 sorption capacity was maintained when the gas composition was changed to 15% CO2, and the hybrid material exhibited satisfactory performances during the 10 recycle runs. 相似文献
13.
Highly Effective Oxidative Dehydrogenation of Propane Over Vanadia Supported on Mesoporous SBA-15 Silica 总被引:1,自引:0,他引:1
Vanadia-containing mesoporous SBA-15 catalysts were prepared and characterized for the oxidative dehydrogenation (ODH) of propane. It is demonstrated that the vanadia-supported SBA-15 catalysts exhibit a much higher catalytic activity than those reported in the literature obtained over vanadium-supported mesoporous MCM-41 catalysts in the ODH of propane. The high catalytic performance of the mesoporous SBA-15 catalysts is attributed to the particularly large pore diameters and low surface acidity. 相似文献
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15.
以正硅酸乙酯为硅源,丙醇锆为锆源,十六烷基三甲基溴化铵为模板剂,通过水热合成法制备Zr-MCM-48介孔材料,提高材料的耐碱性能.利用XRD、N2吸附-脱附、XPS等手段对产物进行了结构和性能的分析.XRD检测显示当Zr/Si物质的量比小于0.1时,可以获得长程有序的MCM-48结构.N2吸附-脱附实验、XPS测试等证实Zr已经掺入MCM-48骨架中.稳定性实验结果表明Zr/Si物质的量比为0.03时,Zr-MCM-48材料的耐碱性能明显增强,进一步表明Zr掺入了MCM-48材料的骨架中. 相似文献
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Ordered mesoporous materials are attracting wide concern because of their applications in the field of catalysis, adsorption, separations, drug delivery systems and gas sensors owing of their extremely high surface area combined with well-defined pore structures with narrow pore size distributions. Various mesoporous materials such as MCM-41, MCM-48, SBA-15 and SBA-16 have been reported in past two decades. Synthesis of mesoporous materials involves the concept of aggregation of surfactants as structure directing agents under acidic or basic conditions. The dimensions of these mesopores can be obtained by type of surfactant, auxiliary chemicals and synthesis conditions. At present, SBA-15 has attracted more attention among different mesoporous silica structures due to their desirable properties such as thick pore wall and hexagonal mesopores (4–12 nm), high surface area, ease of synthesis and functionalization and high thermal and mechanical stability. In last few years, great effort has been made on the development of various methods for the synthesis of mesoporous materials as support for oxidation reactions. The aim of this review article is to focus mainly on mesoporous SBA-15 together with its application as support for various oxidation reactions. 相似文献
18.
Kiwilsza Anna Milanowski Bartłomiej Drużbicki Kacper Coy L. Emerson Grzeszkowiak Mikołaj Jarek Marcin Mielcarek Jadwiga Lulek Janina Pajzderska Aleksandra Wąsicki Jan 《Journal of Porous Materials》2015,22(3):817-829
Journal of Porous Materials - Two mesoporous silica materials: MCM-41 and SBA-15 were applied as potential nanocarriers for poorly soluble drug—nimodipine. Drug incorporation was performed... 相似文献
19.
在多巴胺修饰的水基TiO_2纳米微粒(TiO_2NPs)悬浮液中,以正硅酸乙酯为硅源,十六烷基三甲基溴化铵为模板剂,分别采用碱性水热方法或酸性溶胶-凝胶方法,制备了有序介孔TiO_2-SiO_2(TiO_2NPs/MCM-41或TiO_2NPs/SBA-3)。采用XRD、TEM、ICP和N2吸附-脱附实验对样品进行表征。结果表明,制备的介孔TiO_2-SiO_2在TiO_2高负载质量分数(23.98%TiO_2NPs/MCM-41、17.27%TiO_2NPs/SBA-3)时,仍能保持长程有序的介孔氧化硅结构。TiO_2NPs随机地嵌入在有序介孔氧化硅孔道所组成的网络结构中。在可见光下催化甲基橙降解反应中,反应时间120 min时,在P25上甲基橙相对浓度降为57%,在TiO_2NPs/MCM-41上降为33%,而在TiO_2NPs/SBA-3上降为5.7%。 相似文献
20.
Yuye Zhao Sheng Sun Xuefan Cai Yuchi Fan Wan Jiang Beiying Zhou Shijia Gu Nian Shi Wei Luo Lianjun Wang 《Journal of the American Ceramic Society》2020,103(10):5654-5663
In this study, the sintering behaviors of a series of mesoporous silica (FDU-12, SBA-15, MCM-41, and mesoporous silica nanoparticles) and microporous zeolite (ZSM-5) using spark plasma sintering (SPS) technology were investigated. Highly transparent glass was prepared at a low temperature from all the powders. In particular, FDU-12 type of mesoporous silica could be fully densified at an ultralow sintering temperature (910°C). It is suggested that the collapse of ordered mesostructures during SPS process dependents on the large pore size/pore wall thickness ratio, appropriate pore arrangement and amorphous frameworks of mesoporous silica, which implies that the enhancement in sinterability is possibly derived from the in situ collapse of ordered mesostructures. Such present findings pave a new way toward the construction of functional dense bulk materials from mesoporous powders. 相似文献