Journal articles: 'Silicalite'

1

He, Qiuping, Wei Chen, Pengfei Wang, and Xiaoming Dou. "Silicalite-1/PDMS Hybrid Membranes on Porous PVDF Supports: Preparation, Structure and Pervaporation Separation of Dichlorobenzene Isomers." Polymers 14, no. 9 (April 21, 2022): 1680. http://dx.doi.org/10.3390/polym14091680.

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Separation of dichlorobenzene (DCB) isomers with high purity by time− and energy−saving methods from their mixtures is still a great challenge in the fine chemical industry. Herein, silicalite-1 zeolites/polydimethylsiloxane (PDMS) hybrid membranes (silicalite-1/PDMS) have been successfully fabricated on the porous polyvinylidene fluoride (PVDF) supports to first investigate the pervaporation separation properties of DCB isomers. The morphology and structure of the silicalite-1 zeolites and the silicalite-1/PDMS/PVDF hybrid membranes were characterized by XRD, FTIR, SEM and BET. The results showed that the active silicalite-1/PDMS layers were dense and continuous without any longitudinal cracks and other defects with the silicalite-1 zeolites content no more than 10%. When the silicalite-1 zeolites content exceeded 10%, the surfaces of the active silicalite-1/PDMS layers became rougher, and silicalite-1 zeolites aggregated to form pile pores. The pervaporation experiments both in single-isomer and binary−isomer systems for the separation of DCB isomers was further carried out at 60 °C. The results showed that the silicalite-1/PDMS/PVDF hybrid membranes with 10% silicalite-1 zeolites content had better DCB selective separation performance than the silicalite-1/α−Al2O3 membranes prepared by template method. The permeate fluxes of the DCB isomers increased in the order of m−DCB < o−DCB < p−DCB both in single-isomer and binary-isomers solutions for the silicalite-1/PDMS/PVDF hybrid membranes. The separation factor of the silicalite-1/PDMS/PVDF hybrid membranes for p/o−DCB was 2.9 and for p/m−DCB was 4.6 in binary system. The permeate fluxes of the silicalite-1/PDMS/PVDF hybrid membranes for p−DCB in p/o−DCB and p/m−DCB binary−isomers solutions were 126.2 g∙m−2∙h−1 and 104.3 g∙m−2∙h−1, respectively. The thickness−normalized pervaporation separation index in p/o−DCB binary−isomers solutions was 4.20 μm∙kg∙m−2∙h−1 and in p/m−DCB binary−isomers solutions was 6.57 μm∙kg∙m−2∙h−1. The results demonstrated that the silicalite-1/PDMS/PVDF hybrid membranes had great potential for pervaporation separation of DCB from their mixtures.

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2

Thongkam, Montree, Somsak Woramongkolchai, Sairoong Saowsupa, and Pesak Rungrojchaipon. "A Facile Method to Synthesize b-Oriented Silicalite-1 Thin Film." Membranes 12, no. 5 (May 13, 2022): 520. http://dx.doi.org/10.3390/membranes12050520.

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Silicalite-1 thin film was prepared with the following batch composition—3TPAOH:25TEOS:1450H2O:100EtOH—and synthesized using the hydrothermal technique. Silicalite-1 colloidal crystals were successfully coated on the surface of the silica substrate by the dip-coating method. The investigation of silicalite-1 thin film with organic structure-directing agents (SDA), using a seeding technique with various colloidal seed concentrations, number of dip-coating steps, and crystallization time, were systematically discussed and obtained interesting results. Silicalite-1 powder and Silicalite-1 membrane, the patterns of which showed a unique characteristic crystallography of MFI topology, were characterized by XRD, which indicated the preferred orientation along the b-axis perpendicular to the substrate surface. The morphology and crystal size aspect of Silicalite-1 were also examined by a scanning electron microscope (SEM).

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3

Marthosa, Sutida, Wirote Youravong, Chaiwat Kongmanklang, and Watsa Khongnakorn. "Applications and characterization of silicalite-1/polydimethylsiloxane composite membranes for the pervaporation of a model solution and fermentation broth." Journal of Polymer Engineering 39, no. 2 (February 25, 2019): 152–60. http://dx.doi.org/10.1515/polyeng-2018-0138.

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AbstractEthanol recovery via pervaporation is greatly influenced by membrane separation performance, which can be enhanced by adding hydrophobic fillers such as silicalite-1. Silicalite-1 was prepared by controlling the gel molar composition in hydrothermal synthesis, and it was incorporated into a polydimethylsiloxane (PDMS) membrane on Teflon. The silicalite-1 Si-O-Si structures interacted with the -Si(CH3)2-O- backbone of the PDMS chain. The thermal gravimetric analysis results showed that the silicalite-1 improved the thermal stability and raised the initial decomposition temperature from 405°C to 450–470°C. Increasing silicalite-1 content from 5 to 20 wt% enhanced the relative ethanol/water swelling from 1.33% to 1.52% and advanced the contact angle from 112.6° to 138.6°. Addition of 20 wt% silicalite-1 improved the separation factor in broth from 2.55 to 5.56. When using 20 wt% silicalite-1/PDMS membrane and replacing the ethanol solution with broth, fouling reduced the flux from 597 to 482 g m−2h−1, but the broth composite increased the separation factor from 3.14 to 5.56. The overall pervaporation separation index with a santol broth of the 20 wt% silicalite-1/PDMS and commercial PDMS membranes were 2199 and 2110. The prepared membranes had similar overall performance as a commercial membrane.

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Zieliński, Michał, Ewa Janiszewska, Adrianna Drewniak, and Mariusz Pietrowski. "Methanation of CO2 over Ruthenium Supported on Alkali-Modified Silicalite-1 Catalysts." Molecules 28, no. 17 (August 31, 2023): 6376. http://dx.doi.org/10.3390/molecules28176376.

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This study focuses on the catalytic properties of ruthenium catalysts supported on modified silicalite-1 (with an MFI structure). By post-synthesis modification of silicalite-1 with solutions of alkali metal compound, a novel and cost-effective method was discovered to create basic centers on the surface of silicalite-1 supports. The modification not only affected the basicity of the supports but also their porosity. The influence of the type of alkali solution (KOH or NaOH) and its concentration (0.1 M or 1.0 M) on both the basicity and porosity was investigated. The modified silicalite-1 materials were employed as supports for ruthenium catalysts (1 wt.% Ru) and evaluated for their CO2 methanation activity. The results were compared with the hydrogenation performance of ruthenium catalysts supported on unmodified silicalite-1. Characterization of the supports and catalysts was conducted using techniques such as BET, XRD, FT-IR, ICP-OES, TPR-H2, H2 chemisorption, TPD-CO2, SEM, and TEM. Remarkably, the catalytic activity of ruthenium supported on silicalite-1 treated with 1.0 M NaOH (exhibiting selectivity toward methane above 90% in a reaction temperature range of 250–450 °C) outperformed both unmodified and KOH-modified silicalite-1 supported Ru catalysts.

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5

Sakai, Motomu, Yukichi Sasaki, Takuya Kaneko, and Masahiko Matsukata. "Contribution of Pore-Connectivity to Permeation Performance of Silicalite-1 Membrane; Part I, Pore Volume and Effective Pore Size." Membranes 11, no. 6 (May 24, 2021): 382. http://dx.doi.org/10.3390/membranes11060382.

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The micropore volumes and effective pore sizes of two types of silicalite-1 membranes were compared with those of a typical silicalite-1 powder. The silicalite-1 membrane with fewer grain boundaries in the membrane layer showed similar micropore volume and effective pores size to those of the silicalite-1 powder. In contrast, when the silicalite-1 membrane contained many grain boundaries, relatively small micropore volume and effective pore size were observed, suggesting that narrowing and obstruction of the micropore would occur along grain boundaries due to the disconnection of the zeolite pore. The silicalite-1 membrane with fewer grain boundaries exhibited relatively high permeation properties for C6-C8 hydrocarbons. There was an over 50-fold difference in benzene permeance between these two types of membranes. We concluded that it is important to reduce grain boundaries and improve pore-connectivity to develop an effective preparation method for obtaining a highly permeable membrane.

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6

Lu, Shih-Yuan, Hsiang-Yuan Huang, and Kwen-Hua Wu. "Silicalite/poly(dimethylsiloxane) nanocomposite pervaporation membranes for acetic acid/water separation." Journal of Materials Research 16, no. 11 (November 2001): 3053–59. http://dx.doi.org/10.1557/jmr.2001.0422.

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Composite separation membranes of poly(dimethylsiloxane) (PDMS) containing well-dispersed silicalite particles of 50 nm were successfully prepared and applied to the preferential pervaporation of acetic acid over water. The nanocomposite membranes showed improvement on both separation factor and permeation flux for the pervaporation process, as compared to plain PDMS membranes and composite membranes containing silicalite particles of 5 μm. The improvement can be attributed to higher readily accessible specific surface area and higher sorption selectivity toward acetic acid of the nano-size silicalite particles. Improvement on membrane thermal stability was also acquired through incorporation of nano-size silicalite particles.

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7

Deng, Kang, Liangjun Xiao, Junming Xie, Shunheng Tu, and Yongfeng Li. "Novel Pd-loaded self-standing hierarchical pore structure silicalite for low temperature toluene catalytic combustion." Journal of Physics: Conference Series 2342, no. 1 (September 1, 2022): 012001. http://dx.doi.org/10.1088/1742-6596/2342/1/012001.

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Abstract A novel Pd-loaded self-standing hierarchical pore structure silicalite were obtained by a handy polymer form board assisted hydrothermal method. The selected foam-shaped form board of a polyurethane (PU) foam monolith was regarded as the precursor of the self-standing hierarchical pore structure silicalite. The fruiting silicalite can steadily hold unique macroporous network structure and shape of the anterior original PU foam board . By means of the BET and BJH pore size distribution tests, the as-synthesis silicalite demonstrated hierarchical pore structure. The method of in-situ reduction was wielded to load palladium on the silicalite, and the catalytic performance of the catalyst to decompose toluene was tested at multiple burning temperatures. The experimental results revealed that the Pd-loaded catalyst can effectively decompose toluene at nearly 230°C, realizing low-temperature catalytic combustion of toluene.

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8

Chen, Hong Liang, Ji Song Yang, Yan Wang, Hui Ying Li, Xin Xin Li, and Wei Shen Yang. "Preparation of Silicalite-1 Membranes with Seeding Method and its Separation Performance for Low Ethanol/Water Mixture." Advanced Materials Research 807-809 (September 2013): 591–95. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.591.

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High performance silicalite-1 membranes were successfully synthesized on silica tubes by seeding method after filling the tubes with water and glycerol mixtures. After seeding the silica tubes with 200 nm seeds, all the silicalite-1 membranes show acceptable separation performance towards ethanol/water mixture after 4-12 h hydrothermal synthesis, and the highest flux of membrane with 8 h hydrothermal synthesis reaches about 0.98 kg/m2.h and the separation factor reaches about 60 towards 3 wt.% ethanol/water mixture. This result shows that the as-synthesized silicalite-1 membrane can concentrate the ethanol from 3% to about 65%, and the ethanol can be obtained over 600 g/m2.h by using the silicalite-1 membrane, which shows that seeding method and suitable control of synthesis conditions is possible for preparing high-performance silicalite-1 membranes.

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9

Cheng, Yue, Shun Long Pan, and Yuan Zhou. "Study on Magnetic Mn_0.2Co_0.8Fe₂O₄/Silicalite-2 Catalyst and its Electro-Catalytic Property." Advanced Materials Research 669 (March 2013): 30–33. http://dx.doi.org/10.4028/www.scientific.net/amr.669.30.

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Silicalite-2 zeolite was hydrothermally synthesized and Mn0.2Co0.8Fe2O4 magnetic nano-particle based on the Silicalite-2 zeolite carrier was prepared by a coprecipitation-impregnation method. The morphologies and microstructures of synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). The heterogeneous catalytic oxidation electrolysis system of Mn0.2Co0.8Fe2O4/silicalite-2 was built by dispersing the catalysts in glass reactor for treating cationic brilliant red X-5GN wastewater. The SEM images showed that the structure of silicalite-2 zeolite remained its original after the introduction of Mn0.2Co0.8Fe2O4 magnetic particle. The XRD patterns revealed that Mn0.2Co0.8Fe2O4 oxides could not be observed on the surface of the silicalite-2 zeolite carrier. The experimental results showed that the dye wastewater with a satisfied decolorization rate (79.1%) was obtained when the initial pH was 6, the magnetic catalyst dosage was 0.4g/L, the electrolysis voltage was 2V, electrolytic time was 45min, respectively.

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10

Chen, Sheng, Guofeng Li, and Qipeng Yuan. "High adsorption capacity by creating a hydrophobic/hydrophilic layer on the surface of silicalite-1." RSC Advances 6, no. 101 (2016): 99509–13. http://dx.doi.org/10.1039/c6ra21257c.

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11

Creci, Simone, Anna Martinelli, Szilvia Vavra, Per-Anders Carlsson, and Magnus Skoglundh. "Acidity as Descriptor for Methanol Desorption in B-, Ga- and Ti-MFI Zeotypes." Catalysts 11, no. 1 (January 12, 2021): 97. http://dx.doi.org/10.3390/catal11010097.

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The isomorphous substitution of Si with metals other than Al in zeotype frameworks allows for tuning the acidity of the zeotype and, therefore, to tailor the catalyst’s properties as a function of the desired catalytic reaction. In this study, B, Ga, and Ti are incorporated in the MFI framework of silicalite samples and the following series of increasing acidity is observed: Ti-silicalite < B-silicalite < Ga-silicalite. It is also observed that the lower the acidity of the sample, the easier the methanol desorption from the zeotype surface. In the target reaction, namely the direct conversion of methane to methanol, methanol extraction is affected by the zeotype acidity. Therefore, the results shown in this study contribute to a more enriched knowledge of this reaction.

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12

Chen, Hong Liang, Bin Bin Yang, Ji Song Yang, Yan Wang, and Hui Ying Li. "Synthesis of Silicalite-1 Membrane with High-Thermal Stability on Silica Tubes by In Situ Hydrothermal Synthesis." Applied Mechanics and Materials 692 (November 2014): 391–95. http://dx.doi.org/10.4028/www.scientific.net/amm.692.391.

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Silicalite-1 membranes with high-thermal stability were prepared on silica tubes by two-step hydrothermal synthesis after filling the tubes with water and glycerol mixtures. It was found that the filling method can improve the membrane separation performance effectively. After filling the silica tubes with mixed solution, the average flux of silicalite-1 membranes was improved by 23% while keeping the separation selectivity nearly unchanged. The results showed that the silicalite-1 membrane still showed high separation performance towards ethanol/water mixture after the repeated calcination at 400°C for 5 h, even with a calcination rate of 4 °C/min, which suggested that silica tubes may be very suitable to synthesize high-performance silicalite-1 membranes in large area.

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13

Casal, H. L., and J. C. Scaiano. "Intrazeolite photochemistry. II. Evidence for site inhomogeneity from studies of aromatic ketone phosphorescence." Canadian Journal of Chemistry 63, no. 6 (June 1, 1985): 1308–14. http://dx.doi.org/10.1139/v85-222.

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The luminescent properties of several aromatic ketones included in the hydrophobic zeolite Silicalite have been examined. Acetophenone, benzophenone, and β-phenylpropiophenone show readily detectable phosphorescence; by contrast, valerophenone does not luminesce, but undergoes the Norrish Type II reaction. Thus, irradiated samples of valerophenone in Silicalite show phosphorescence due to the accumulation of acetophenone. In the case of β-phenylpropiophenone the triplet lifetime is ca. 100 000 times longer than the solution value, suggesting severe conformational restrictions. Co-inclusion of acetophenone with various substrates and oxygen quenching studies indicate that Silicalite has at least two distinct classes of inclusion sites. In one of them energy transfer processes are rapid and efficient, suggesting a cooperative effect in the inclusion of ketones in these regions of the Silicalite framework.

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14

Gautam, Siddharth, Tingting Liu, and David Cole. "Sorption, Structure and Dynamics of CO2 and Ethane in Silicalite at High Pressure: A Combined Monte Carlo and Molecular Dynamics Simulation Study." Molecules 24, no. 1 (December 28, 2018): 99. http://dx.doi.org/10.3390/molecules24010099.

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Silicalite is an important nanoporous material that finds applications in several industries, including gas separation and catalysis. While the sorption, structure, and dynamics of several molecules confined in the pores of silicalite have been reported, most of these studies have been restricted to low pressures. Here we report a comparative study of sorption, structure, and dynamics of CO2 and ethane in silicalite at high pressures (up to 100 bar) using a combination of Monte Carlo (MC) and molecular dynamics (MD) simulations. The behavior of the two fluids is studied in terms of the simulated sorption isotherms, the positional and orientational distribution of sorbed molecules in silicalite, and their translational diffusion, vibrational spectra, and rotational motion. Both CO2 and ethane are found to exhibit orientational ordering in silicalite pores; however, at high pressures, while CO2 prefers to reside in the channel intersections, ethane molecules reside mostly in the sinusoidal channels. While CO2 exhibits a higher self-diffusion coefficient than ethane at low pressures, at high pressures, it becomes slower than ethane. Both CO2 and ethane exhibit rotational motion at two time scales. At both time scales, the rotational motion of ethane is faster. The differences observed here in the behavior of CO2 and ethane in silicalite pores can be seen as a consequence of an interplay of the kinetic diameter of the two molecules and the quadrupole moment of CO2.

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15

Doubkova, Martina, Ivana Nemcakova, Ivan Jirka, Vitezslav Brezina, and Lucie Bacakova. "Silicalite-1 Layers as a Biocompatible Nano- and Micro-Structured Coating: An In Vitro Study on MG-63 Cells." Materials 12, no. 21 (October 31, 2019): 3583. http://dx.doi.org/10.3390/ma12213583.

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Silicalite-1 is a purely siliceous form of zeolite, which does not contain potentially harmful aluminum in its structure as opposed to ZSM-5 aluminosilicate types of zeolite. This paper reports on a study of a silicalite-1 film, deposited on a silicon Si(100) substrate, as a potential anti-corrosive and biocompatible coating for orthopaedic implants. Silicalite-1 film was prepared in situ on the surface of Si(100) wafers using a reaction mixture of tetrapropyl-ammonium hydroxide (TPAOH), tetraethyl-orthosilicate (TEOS), and diH2O. The physico-chemical properties of the obtained surface were characterized by means of X-ray photoelectron spectroscopy, water contact angle measurement, atomic force microscopy, and scanning electron microscopy. The biocompatibility was assessed by interaction with the MG-63 cell line (human osteosarcoma) in terms of cell adhesion, morphology, proliferation, and viability. The synthesized silicalite-1 film consisted of two layers (b- and a, b-oriented crystals) creating a combination of micro- and nano-scale surface morphology suitable for cell growth. Despite its hydrophobicity, the silicalite-1 film increased the number of initially adhered human osteoblast-like MG-63 cells and the proliferation rate of these cells. The silicalite-1 film also improved the cell viability in comparison with the reference Si(100) substrate. It is therefore a promising candidate for coating of orthopaedic implants.

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Zhao, Jing, Yifu Zhang, Fuping Tian, Yi Zuo, Yang Mu, and Changgong Meng. "High pH promoting the synthesis of V-Silicalite-1 with high vanadium content in the framework and its catalytic performance in selective oxidation of styrene." Dalton Transactions 47, no. 33 (2018): 11375–85. http://dx.doi.org/10.1039/c8dt02042f.

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V-Silicalite-1 with a high vanadium content in the framework was synthesized. OH⁻ ions effectively promoted the entry of vanadium atoms into the framework. The V-Silicalite-1 exhibited good catalytic performance.

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17

Astorino, E., J. B. Peri, R. J. Willey, and G. Busca. "Spectroscopic Characterization of Silicalite-1 and Titanium Silicalite-1." Journal of Catalysis 157, no. 2 (December 1995): 482–500. http://dx.doi.org/10.1006/jcat.1995.1313.

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18

Deng, Yi-Qiang, Wei-Fang Zhou, Hao-Ming Lv, Ying-Ying Zhang, Chak-Tong Au, and Shuang-Feng Yin. "Synthesis of HZSM-5@silicalite-1 core–shell composite and its catalytic application in the generation of p-xylene by methylation of toluene with methyl bromide." RSC Adv. 4, no. 70 (2014): 37296–301. http://dx.doi.org/10.1039/c4ra04126g.

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A core–shell HZSM-5@silicalite-1 composite was synthesized by overgrowing silicalite-1 on the external surface of HZSM-5, and was characterized by XRD, SEM, TEM, NH₃-TPD, 1,3,5-triisopropylbenzene (TIPB) cracking and BET methodsdesorption techniques.

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19

Lee, L. Y., S. P. Perera, B. D. Crittenden, and S. T. Kolaczkowski. "Manufacture and Characterisation of Silicalite Monoliths." Adsorption Science & Technology 18, no. 2 (March 2000): 147–70. http://dx.doi.org/10.1260/0263617001493350.

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Multichannel monoliths containing up to 90% silicalite by weight and with cell densities up to 28 cells/cm2, wall thicknesses down to 0.6 mm and an overall diameter of 40 mm have been prepared from silicalite powder and sodium bentonite (as a binder) by the unit operations of paste preparation, extrusion, drying and firing. The manufactured monoliths, which show good strength, retain the crystal structure and micropore size of the source silicalite powder, and adsorption measurements made by using a dynamic flow system confirm that the monoliths exhibit an equilibrium performance broadly similar to that of commercial silicalite pellets. In addition, the manufactured monoliths possess a higher macroporosity than the commercial pellets. Regeneration of the monoliths was found to be possible at mildly increased temperature. These features augur well for the recovery and/or separation of organic compounds in simple pressure swing and thermal swing processes.

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Da Silva, J. P., and L. F. Vieira Ferreira. "A comparative study of the photochemistry of biphenyl adsorbed on cellulose and silicalite." International Journal of Photoenergy 6, no. 4 (2004): 193–98. http://dx.doi.org/10.1155/s1110662x04000248.

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The photochemistry of biphenyl (BP) was studied on two model solid supports, silicalite and cellulose, using time resolved diffuse reflectance techniques and product degradation analysis. The results showed that the photochemical behaviour of BP depends on the solid support. Ground state absorption spectra indicated a near planar configuration in the ground state. BP triplet state was the only species detected on cellulose, while the radical cation(BP•+)was observed in silicalite. BP is relatively stable in both supports. Prolonged irradiations in cellulose lead to the formation of the three monohydroxybiphenyls, while in silicalite photooxidation products prevailed.

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Yang, Xiaobing, Chuanhai Gan, Huaping Xiong, Liuqing Huang, and Xuetao Luo. "Fabrication and characterization of SiO2@TiO2@silicalite-1 catalyst and its application for degradation of rhodamine B." RSC Advances 6, no. 107 (2016): 105737–43. http://dx.doi.org/10.1039/c6ra23883a.

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SiO₂@TiO₂@silicalite-1 catalyst, with TiO₂ (Degussa P25) nanoparticles encapsulated by SiO₂ and adhered on the surface of silicalite-1 zeolite, was successfully fabricated by combining pressing, sintering and infiltration methods.

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Zieliński, Michał, Monika Kot, Mariusz Pietrowski, Robert Wojcieszak, Jolanta Kowalska-Kuś, and Ewa Janiszewska. "Studies of New Iridium Catalysts Supported on Modified Silicalite-1—Their Structure and Hydrogenating Properties." Materials 14, no. 16 (August 9, 2021): 4465. http://dx.doi.org/10.3390/ma14164465.

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This paper investigates the catalytic properties of the iridium catalysts supported on modified silicalite-1. Post-synthesis modification of silicalite-1, with solutions of ammonium compounds (NH4F and NH4OH), appeared to be an efficient method to generate the acidic sites in starting support. The modification of support led not only to changes in its acidity but also its porosity—formation of additional micro- and mesopores. The novel materials were used as supports for iridium. The iridium catalysts (1 wt.% Ir) were characterized by N2 adsorption/desorption measurements, temperature-programmed reduction with hydrogen (TPR-H2), H2 chemisorption, transmission electron microscopy (TEM), temperature-programmed desorption of ammonia (TPD-NH3), X-ray photoelectron spectroscopy (XPS) and tested in the hydrogenation of toluene reaction. The catalytic activity of iridium supported on silicalite-1 treated with NH4OH (higher porosity of support, better dispersion of active phase) was much higher than that of Ir supported on unmodified and modified with NH4F silicalite-1.

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Sakai, Motomu, Takuya Kaneko, Yukichi Sasaki, Miyuki Sekigawa, and Masahiko Matsukata. "Formation Process of Columnar Grown (101)-Oriented Silicalite-1 Membrane and Its Separation Property for Xylene Isomer." Crystals 10, no. 10 (October 17, 2020): 949. http://dx.doi.org/10.3390/cryst10100949.

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Silicalite-1 membrane was prepared on an outer surface of a tubular α-alumina support by a secondary growth method. Changes of defect amount and crystallinity during secondary growth were carefully observed. The defect-less well-crystallized silicalite-1 membrane was obtained after 7-days crystallization at 373 K. The silicalite-1 membrane became (h0l)-orientation with increasing membrane thickness, possibly because the orientation was attributable to “evolutionally selection”. The (h0l)-oriented silicalite-1 membrane showed high p-xylene separation performance for a xylene isomer mixture (o-/m-/p-xylene = 0.4/0.4/0.4 kPa). The p-xylene permeance through the membrane was 6.52 × 10−8 mol m−2 s−1 Pa−1 with separation factors αp/o, αp/m of more than 100 at 373 K. As a result of microscopic analysis, it was suggested that a very thin part in the vicinity of surface played as effective separation layer and could contribute to high permeation performance.

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Knappe, D. R. U., and A. A. Rossner Campos. "Effectiveness of high-silica zeolites for the adsorption of methyl tertiary-butyl ether from natural water." Water Supply 5, no. 5 (December 1, 2005): 83–91. http://dx.doi.org/10.2166/ws.2005.0042.

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MTBE adsorption isotherm data were collected for a matrix of high-silica zeolites with different pore sizes (ZSM-5/silicalite, mordenite, beta, Y), exchangeable cations (H+, Na+, NH4+), and hydrophobicities (SiO2/Al2O3 ratios). MTBE adsorption capacities of high-silica zeolites were compared with those of one coconut-shell-based and two coal-based granular activated carbons (GACs) as well as a carbonaceous resin. Isotherm experiments were conducted in ultrapure water buffered at pH 7.2 and in Tar River water (Greenville, NC) to determine the effects of co-adsorbing and preloaded natural organic matter (NOM) on MTBE adsorption. The results of this study showed that (1) high-silica zeolites with small pores (ZSM-5/silicalite, mordenite) exhibit higher MTBE adsorption capacities than GACs, (2) NOM has little or no effect on MTBE adsorption capacities of ZSM-5/silicalite zeolites, and (3) equilibrium model results suggest that silicalite-based adsorption systems are cost-competitive with activated-carbon-based adsorption systems while offering operational advantages such as longer adsorber life and possibly greater ease of regeneration.

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Fujiyama, Shinjiro, Shintaro Seino, Natsumi Kamiya, Koji Nishi, and Yoshinobu Yokomori. "Adsorption structure of dimethyl ether on silicalite-1 zeolite determined using single-crystal X-ray diffraction." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 70, no. 5 (October 1, 2014): 856–63. http://dx.doi.org/10.1107/s2052520614015911.

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The adsorption structures of dimethyl ether (DME) on silicalite-1 zeolite (MFI-type) are determined using single-crystal X-ray diffraction. The structure of low-loaded DME-silicalite-1 indicates that all DME molecules are located in the sinusoidal channel, which is the most stable sorption site based on the van der Waals interaction between DME and the framework. The configuration of guest molecules (linear or bent) plays an important role in determining where the stable sorption site is in the pore system of MFI-type zeolites. Bent molecules favor the sinusoidal channel, while linear molecules favor the straight channel. The contribution of DME–DME interactions is considerable in the high-loaded DME-silicalite-1 structure.

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Kamiya, Natsumi, Wataru Iwama, Tomokazu Kudo, Tomomi Nasuno, Shinjiro Fujiyama, Koji Nishi, and Yoshinobu Yokomori. "Determining the structure of a benzene7.2-silicalite-1 zeolite using a single-crystal X-ray method." Acta Crystallographica Section B Structural Science 67, no. 6 (October 13, 2011): 508–15. http://dx.doi.org/10.1107/s0108768111038560.

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A simple method for preparing orthorhombic single crystals of benzene-silicalite-1 was developed. A silicalite-1 crystal was pressed with a weight of 2 g along the +c and −c crystallographic axes while the temperature was increased to 473 K. The temperature was then slowly reduced to 313 K, and these heating and cooling steps were repeated three times. After the orthorhombic single crystals adsorbed benzene, the crystal structure of the resulting benzene-silicalite-1 was determined. There were two kinds of benzene molecules in the asymmetric unit. One was located at the intersection of the straight channels and the sinusoidal channels with the benzene ring parallel to the ac plane. The other benzene was located in the middle of the straight channel.

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Yashnik, Svetlana A., Tatjana A. Surovtsova, Anton V. Salnikov, and Valentin N. Parmon. "Leaching Stability and Redox Activity of Copper-MFI Zeolites Prepared by Solid-State Transformations: Comparison with Ion-Exchanged and Impregnated Samples." Materials 16, no. 2 (January 10, 2023): 671. http://dx.doi.org/10.3390/ma16020671.

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The catalyst preparation route is well known to affect the copper loading and its electronic state, which influence the properties of the resulting catalyst. Electronic states of copper ions in copper-containing silicalites with the MFI-framework topology obtained by a solid-state transformation S (SST) were studied with using EPR, UV-Vis DR, XRD, H2-TPR and chemical differentiating dissolution. They were compared with Cu-ZSM-5 and Cu-MFI (silicalite) prepared via the ion-exchange and incipient wetness impregnation. SST route was shown to provide the formation of MFI structure and favor clustering of Cu-ions near surface and subsurface of zeolite crystals. The square-planar oxide clusters of Cu2+-ions and the finely dispersed CuO nanoparticles with the size down to 20 nm were revealed in Cu-MFI-SST samples with low (0.5–1.0 wt.%) and high (16 wt.%) Cu-content. The CuO nanoparticles were characterized by energy band gap 1–1.16 eV. The CuO-like clusters were characterized by ligand-to-metal charge transfer band (CTB L → M) at 32,000 cm−1 and contain EPR-visible surface Cu2+-ions. The low Cu-loaded SST-samples had poor redox properties and activity towards different solvents due to decoration of copper-species by silica; whereas CuO nanoparticles were easily removed from the catalyst by HCl. In the ion-exchanged samples over MFI-silicalite and ZSM-5, Cu2+-ions were mainly CuO-like clusters and isolated Cu2+ ions inside MFI channels. Their redox properties and tendency to dissolve in acidic solutions differed from the behavior of SST-series samples.

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Куцова, Д. С., Е. В. Богатиков, А. Н. Шебанов, and Е. Н. Бормонтов. "Метод повышения эффективности тепловой регенерации сенсора на основе силикалита: молекулярно-динамическое моделирование." Письма в журнал технической физики 45, no. 7 (2019): 57. http://dx.doi.org/10.21883/pjtf.2019.07.47541.17642.

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AbstractThe molecular dynamics simulation has been used to find a nonlinear temperature dependence of the sorption/desorption probability coefficients in the methane–silicalite system. A method is proposed for using this nonlinearity to raise the efficiency of methane desorption from the silicalite via oscillatory heating. The results obtained can be used in thermal regeneration of zeolite-based gas-sensitive sensors.

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29

Pan, Xu, Xin Huang, Ruizhuang Wang, Haiyong Zhang, Hui Wei, Jingyun Chen, Suyao Liu, Liping Sun, Deping Xu, and Yi Liu. "Effects of Silicalite-1 Coating on the p-Xylene Selectivity and Catalytic Stability of HZSM-5 in Toluene Methylation with Methanol." Catalysts 12, no. 12 (November 29, 2022): 1538. http://dx.doi.org/10.3390/catal12121538.

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The methanol–toluene alkylation process over zeolites catalysts offers a promising route for the production of p-xylene from low-cost feedstocks. Herein, we present a catalyst by preparing a core-shell aluminosilicate zeolite with an epitaxial silicalite-1 shell that passivates acid sites on the exterior surfaces. The para-selectivity was obviously increased due to the inhibition of the unselective isomerization of p-xylene over the external acid sites, and the open porous structure of the silicalite-1 shell ensured the mass transfer of reactants and products. Meanwhile, the carbon deposition was suppressed over HZSM-5@silicalite-1 catalysts, as a result of the decreased external acid sites. Furthermore, pulse chromatographic experiments revealed that the silicalite-1 coating could also improve the separation efficiency of p-xylene over o-xylene and m-xylene, due to the steric hindrance and extended diffusion path, resulting in a higher selectivity for p-xylene compared to that of the parent HZSM-5. The HZSM-5@4%S-1 catalyst showed the highest p-xylene selectivity (>80%) and methanol efficiency (66%), with good catalytic stability throughout the 170 h reaction time.

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30

Rhodes, Christopher J., and Timothy C. Dintinger. "Radiolabelling Measurements of Free Radicals Derived from Aromatic Volatile Organic Compounds Adsorbed in Zeolite Nanomaterials to and above Saturation Loadings." Progress in Reaction Kinetics and Mechanism 36, no. 4 (November 2011): 287–322. http://dx.doi.org/10.3184/146867811x13177993978554.

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Benzene, para-xylene and mesitylene were adsorbed into silicalite, Na - morde- nite, Na - ZSM5 and Li - X zeolites, and studied using the longitudinal field muon spin relaxation (LF-μSRx) technique. The zeolites ZSM5/silicalite and mordenite contain microporous channels while zeolite X has only supercages. For cyclohex- adienyl radicals/benzene adsorbed in Na-ZSM5, silicalite and Na - mordenite, a fraction was detected with a common reorientational activation energy in the region of ca 5kJ mol−1; however, in all cases there appeared a second fraction with an activation energy of ca 12kJmol’. [In Li-X only a single fraction was observed with Ea = 8.1kJ mol−1, from molecules adsorbed in supercages]. Given that high loadings of benzene, beyond the saturation capacities of the zeolites were employed, we believe the two distinct motional distributions represent the channel intersection and channel/external-surface niche locations in ZSM5/silicalite, the latter having the higher activation energy. An extraneous fraction may also be present (possibly as a thin film coating the zeolite grains), which probably also contributes to the detected ca 5 kJ mol−1 component in which, as at the channel-intersections, the motion tends toward bulk behaviour. Mordenite has only a single accessible channel structure and is hence devoid of the relatively unrestricting channel intersecting pores that are present in ZSM5/silicalite. However, the channels are wider (ca 7 A diameter) and we may ascribe therefore, the ca 5 kJ mol−1 fraction to the formation of benzene clusters within these channels that exhibit bulk-type behaviour, while we assign, in analogy with the results for ZSM5/silicalite, the ca 12kJ mol−1 fraction to molecules adsorbed in niches on the external surface. It is thought that the essential difference between the two activation energies is that the ca 5 kJ mol -1 processes involve molecular motion within clusters of benzene molecules with properties similar to the bulk phase (6.6 kJ mol -1 was measured in pure benzene), while those characterised at ca 12kJ mol−1 reflect single benzene molecules or small, ordered molecular clusters interacting with a zeolite surface. The results for dimethylcyclohexadienyl radicals (derived from p-xylene) are rather similar, but indicate slightly reduced activation energies. The larger mesitylene molecules can penetrate zeolite X and (more slowly) mordenite, but are excluded from the internal pores of ZSM5/silicalite.

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31

Hill, SG, K. Kinson, and D. Seddon. "The Crystal Size and Morphology of Silicalite as Influenced by Gel Nucleation Temperature, Alkalinity and Sodium-Chloride Concentration." Australian Journal of Chemistry 41, no. 5 (1988): 783. http://dx.doi.org/10.1071/ch9880783.

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The influence of sodium chloride, nucleation temperature and alkalinity on crystal size and product morphology of silicalite is described for crystallizations at temperatures of about 170�C. Addition of sodium chloride and increasing alkalinity produce crystals with less intergrowth. Nucleating the gel at 90�C before crystallization significantly reduces crystal size. The intergrowths on the faces of silicalite can be separated and features of the interlocking of separate crystal entities revealed.

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32

Moukahhal, Kassem, Bénédicte Lebeau, Ludovic Josien, Anne Galarneau, Joumana Toufaily, Tayssir Hamieh, and T. Jean Daou. "Synthesis of Hierarchical Zeolites with Morphology Control: Plain and Hollow Spherical Beads of Silicalite-1 Nanosheets." Molecules 25, no. 11 (May 31, 2020): 2563. http://dx.doi.org/10.3390/molecules25112563.

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Binderless pure silica zeolites (zeosils) spheres and hollow spheres with a diameter of 20 µm composed of silicalite-1 nanosheets particles were prepared by pseudomorphic transformation of spherical silica beads using different temperatures (110, 130, and 150 °C) and treatment times (1–5 days) in order to adapt the local dissolution rate of silica to the crystallization rate of silicalite-1 nanosheets allowing to preserve the initial morphology of the silica beads. Fully crystalline beads of 20 µm were obtained at 110 °C for 5 days, whereas hollow spheres similar in size were synthesized at higher temperatures. The crystallization process seems to begin at the outer surface of the amorphous silica beads and spreads with the time in the interior of the beads leading to a dissolution of the inner amorphous part of the beads to create zeosil hollow spheres for the highest treatment temperatures (130 and 150 °C). The dissolution rate of the inner amorphous part of the beads increases by increasing the hydrothermal treatment temperature from 130 to 150 °C. The silicalite-1 beads synthesized at 110 °C for 5 days showed to be promising for rapid molecular decontamination by adsorbing n-hexane in larger amount than the silicalite-1 conventional big crystals in powder forms.

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33

Wang, Haiyan, Wilhelm Schwieger, and Yining Huang. "An investigation of the conformational behavior of a chlorinated hydrocarbon, 1,1,2-trichloroethane, adsorbed in zeolites by Raman spectroscopy." Canadian Journal of Chemistry 93, no. 1 (January 2015): 118–25. http://dx.doi.org/10.1139/cjc-2014-0187.

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The conformational behavior of 1,1,2-trichloroethane (TCE) adsorbed in two representative zeolites (silicalite-1 and zeolite L) was investigated by Fourier transform (FT)-Raman spectroscopy in combination with thermogravimetric analysis (TGA) and powder X-ray diffraction (XRD). The results indicate that the conformational properties of the TCE molecules inside a zeolitic host are strongly influenced by both the framework topology and the existence of charge balancing cations. When TCE is adsorbed inside completely siliceous silicalite-1, the population of the trans conformer increases significantly relative to pure liquid. Adsorption of TCE also induces a phase transition from the monoclinic to orthorhombic crystal system in the framework of silicalite-1 at high loading levels. At low loading, the TCE molecules are adsorbed inside the channels of silicalite-1. When at high loading levels, TCE molecules reside at both the channel intersection as well as the midsection of the channels. For zeolite L, the presence of an extra-framework cation shows a strong influence on TCE conformation. The strong interaction of the cation with the large dipole moment of the gauche isomer leads to a large increase in the gauche population. Raman data provide direct evidence that the cations in the framework interact much more strongly with the gauche isomer than the trans isomer.

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34

Zhao, Wei, Bijay Basnet, Sukyoung Kim, and Ik Jin Kim. "Synthesis of Vertically Aligned Carbon Nanotubes on Silicalite-1 Monolayer-Supported Substrate." Journal of Nanomaterials 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/327398.

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Monodisperse magneticFe3O4nanoparticles (NPs) with the size of ca. 3.5 nm were prepared and used as the catalysts for the synthesis of vertically aligned carbon nanotube (VACNT) arrays. A silicalite-1 microcrystal monolayer was used as the support layer between catalyst NPs and the silicon substrate. Compared to our previous report which used radio-frequency- (rf-) sputteredFe2O3film as the catalyst,Fe3O4NPs that were synthesized by wet chemical method showed an improved catalytic ability with less agglomeration. The silicalite-1 crystal monolayer acted as an effective “buffer” layer to prevent the catalyst NPs from agglomerating during the reaction process. It is believed that this is the first report that realizes the vertical alignment of CNTs over the zeolite monolayer, namely, silicalite-1 microcrystal monolayer, instead of using the intermediate anodic aluminum oxide (AAO) scaffold to regulate the growth direction of CNT products.

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35

Sakai, Motomu, Yukichi Sasaki, Takuya Kaneko, and Masahiko Matsukata. "Contribution of Pore-Connectivity to Permeation Performance of Silicalite-1 Membrane; Part II, Diffusivity of C6 Hydrocarbon in Micropore." Membranes 11, no. 6 (May 27, 2021): 399. http://dx.doi.org/10.3390/membranes11060399.

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This study investigated the permeation behaviors of n-hexane and 2-methylpentane through two-types of silicalite-1 membranes that have different pore-connectivity. The permeation mechanisms of these hydrocarbons were able to be explained by the adsorption–diffusion model. In addition, the fluxes through silicalite-1 membranes could be expressed by the modified Fick’s first law. The hydrocarbon fluxes through S-1S with better pore-connectivity were ca. 3–20 times larger than those through S-1M with poor pore-connectivity. For these membranes with different pore-connectivity, the activation energy of diffusion of n-hexane was 17.5 kJ mol−1 for the membrane with better pore-connectivity and 18.0 kJ mol−1 for the membrane with poorer pore-connectivity, whereas for 2-methylpentane it was 17.9 and 33.0 kJ mol−1, respectively. We concluded that the pore-connectivity in silicalite-1 membrane significantly influences the molecular diffusivities.

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36

Zhao, Wei, Ashish Pokhrel, Hyun Sung Kim, Hyung Tae Kim, and Ik Jin Kim. "Synthesis of Carbon Nanotubes from Silicalite-1-Coated Substrates." Key Engineering Materials 512-515 (June 2012): 275–79. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.275.

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Assembled monolayer of silicalite-1 (AMS) microcrystals on Si wafer for carbon nanotube (CNT) growth has been prepared by the rubbing method. Iron oxide (α-Fe2O3, hematite) catalyst films were deposited onto silicate-1 monolayers from a Fe2O3 target by radio frequency (rf)-sputtering. This approach has the potential for producing well-aligned CNTs with controlled diameter from predesigned silicalite-1 templates by catalytic chemical vapor deposition (CCVD). Silicalite-1 monolayer oriented with faces parallel to Si wafer showed only the planes in the forms {0 k 0} lines at (020), (040), (060), (080) and (0100) by XRD. The formation and growth of CNTs by CCVD were achieved on the pores of silicate-1 crystals whereby the pores can be defined as confined spaces (channels, 5.60 Å) in nanometer dimensions acting as a template for a fine dispersion of well-defined Fe2O3 (10-15 nm) particles.

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37

Golden, T. C., and S. Sircar. "Gas Adsorption on Silicalite." Journal of Colloid and Interface Science 162, no. 1 (January 1994): 182–88. http://dx.doi.org/10.1006/jcis.1994.1023.

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38

Kim, Hyun Su, Su Kyung Kang, Haoxiang Zhang, Elsa Tsegay Tikue, Jin Hyung Lee, and Pyung Soo Lee. "Al-ZSM-5 Nanocrystal Catalysts Grown from Silicalite-1 Seeds for Methane Conversion." Energies 14, no. 2 (January 18, 2021): 485. http://dx.doi.org/10.3390/en14020485.

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This study evaluated Al-ZSM-5 nanocrystals grown from silicalite-1 seed crystals as catalysts for the methane dehydroaromatization (MDA) reaction. Silicalite-1 seed crystals sized between 30 and 40 nm were used to grow Al-ZSM-5 under various synthesis conditions. The size of Al-ZSM-5 was significantly affected by the Si/Al ratio (SAR), synthesis time, and silica nutrients/seed crystal ratio (NSR). Larger crystals were obtained with an increased SAR in the synthesis sols. Gradual growth of Al-ZSM-5 occurred with synthesis time, although the growth in crystal size ceased at 5 h of synthesis at 120 °C, indicating the rapid growth of Al-ZSM-5 aided by the silicalite-1 seeds. Precise tuning of Al-ZSM-5 size was possible by changing the nutrient/silicalite-1 seed ratio; a higher NSR led to larger crystals. Two representative Al-ZSM-5 crystals with SARs of 35 and 140 were prepared for catalyst testing, and the crystal sizes were tailored to <100 nm by controlling NSR. The MDA reaction was conducted in the presence of the prepared Al-ZSM-5. The catalyst size exhibited distinct differences in catalyst stability, while the SAR of catalysts did not produce noticeable changes in the catalyst stability of the Al-ZSM-5 crystals and commercial zeolites in this reaction system.

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39

Ueno, Kyohei, Hideyuki Negishi, Takuya Okuno, Hiromasa Tawarayama, Shinji Ishikawa, Manabu Miyamoto, Shigeyuki Uemiya, and Yasunori Oumi. "Effects of Silica-Particle Coating on a Silica Support for the Fabrication of High-Performance Silicalite-1 Membranes by Gel-Free Steam-Assisted Conversion." Membranes 9, no. 4 (April 1, 2019): 46. http://dx.doi.org/10.3390/membranes9040046.

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Silicalite-1 membranes with high pervaporation performance were prepared successfully on a silica-particle-coated tubular silica support using a gel-free steam-assisted conversion (SAC) method. The effects of the silica-particle layer formed on the top surface of the silica support and the physical properties of the silica particles themselves on the membrane-formation process were investigated. The silica particles coated served as the additional silica source for growing the silicalite-1 seed crystal layer into the silicalite-1 membrane. As a result, it was possible to form a dense and continuous membrane even under gel-free conditions. Furthermore, it was found that the properties of the silica particles, such as their primary particle diameter, had a determining effect on their solubility during the steam treatment, that is, on the supply rate of the silica source. The silicalite-1 membrane obtained using the spherical-silica-particle-coated support had an approximately 9-μm-thick separation layer and showed very high pervaporation performance, exhibiting a separation factor of 105 and a flux of 3.72 kg m−2 h−1 for a 10 wt % ethanol/water mixture at 323 K. Thus, the gel-free SAC method can be used with a silica support coated with silica particles to readily prepare high-performance membranes without producing any chemical waste.

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40

Petkovic, Sandra, Borivoj Adnadjevic, and Jelena Jovanovic. "Novel kinetics model for adsorption of pollutant from wastewaters onto zeolites. Kinetics of phenol adsorption on zeolite-type silicalite." Adsorption Science & Technology 37, no. 3-4 (March 4, 2019): 349–64. http://dx.doi.org/10.1177/0263617419833201.

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The kinetics of isothermal adsorption of phenol from an aqueous solution onto the zeolite-type silicalite was investigated. Zeolite-type silicalite was synthesized and its basic physico-chemical properties were determined. Isothermal adsorption kinetics curves of phenol on zeolite-type silicalite were measured at temperature range from 283 to 313 K. By applying Friedman’s differential isoconversional method it was found that the adsorption of phenol on silicalite has one rate determining step. By using the ‘model-fitting’ method it was established that the kinetic of adsorption can be described with theoretical kinetic model of the two-dimensional phase-boundary controlled reaction (model R2). The kinetic parameters, activation energy ([Formula: see text]) and preexponetial factor ( lnA = 14.1 min−1) of phenol adsorption were calculated. The thermodynamic parameters, standard enthalpy (Δ H*), standard entropy (Δ S*) and standard free Gibbs energy of adsorption (Δ G*) were calculated and discussed. A novel model for the kinetics of pollutant adsorption from wastewaters onto zeolites based on the following: zeolite pores have cylindrical shape with average radius r0, pores in zeolite are filled simultaneously by the model ‘layer by layer’, the rate of phenol adsorption is higher than the rate of the growth of the thickness of the adsorption layer was suggested. It has been found that the adsorption kinetics can be completely described by this kinetic model.

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41

Zhang, Jianguang, Xiangping Li, Juping Liu, and Chuanbin Wang. "A Comparative Study of MFI Zeolite Derived from Different Silica Sources: Synthesis, Characterization and Catalytic Performance." Catalysts 9, no. 1 (December 26, 2018): 13. http://dx.doi.org/10.3390/catal9010013.

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In this paper, a comparative study of MFI zeolite derived from different silica sources is presented. Dry gel conversion (DGC) method is used to synthesize silicalite-1 and ZSM-5 with MFI structure. Two kinds of silica sources with different particle sizes are used during the synthesis of MFI zeolite. The as-prepared samples were characterized by X-ray diffraction (XRD), N2-sorption, Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray fluorescence spectrometer (XRF). From the characterization results, it could be seen that the high-quality coffin-like silicalite-1 was synthesized using silica sphere with particle size of 300 nm as silica source, with crystallization time being shortened to 2 h. The schematic diagram of silicalite-1 formation using silica sources with different particle sizes is summarized. ZSM-5 was obtained by adding Al atoms to raw materials during the synthesis of MFI zeolite. The performance of aqueous phase eugenol hydrodeoxygenation over Pd/C-ZSM-5 catalyst is evaluated.

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42

Wei, Ning, Jia Zhang, Hexiang Zhong, Liwei Pan, Zeyu Wang, Juan Wang, and Yi Zhou. "Methane Steam Reforming Over NiO/CexZryO2-Sil-1 Catalyst Prepared by In-Situ Self-Assembly." Journal of Nanoscience and Nanotechnology 19, no. 11 (November 1, 2019): 7416–20. http://dx.doi.org/10.1166/jnn.2019.16620.

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NiO/CexZryO2-Sil-1 catalysts were prepared using an In-Situ self-assembly approach by coupling silicalite-1 and CexZryO2. This one-step synthesis method utilized the high surface area and hydrothermal stability of silicalite-1 and the good oxidation-reduction ability of the CexZryO2, and hence offered high synthesis efficiency. The catalyst structure was examined by N2-physisorption, temperature-programmed reduction, transmission electron microscopy, and X-ray diffraction. All the results showed that silicalite-1 was well-encapsulated by NiO/Ce0.5Zr0.5O2. Furthermore, the effect of the Ce/Zr molar ratio on the performance of the catalysts was investigated in detail. The catalysts were subjected to methane steam reforming at high temperatures to evaluate their catalytic performance. The result showed that the NiO/Ce0.5Zr0.5O2-Sil-1 catalyst exhibited the best performance and its methane conversion efficiency reached up to 99.5%. Even after 16 h of continuous stability test, this catalyst could retain a methane conversion efficiency of 97.8%.

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43

Xu, Guo Liang, Yu Cong, Xin Cheng Wang, Cai Xia Sun, Chun Tian Wu, Xiao Dong Wang, and Tao Zhang. "Synthesis of Silicalite-1 Membranes on the Surface of Stainless Steel." Advanced Materials Research 233-235 (May 2011): 1524–28. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.1524.

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Silicalite-1 (pure silica MFI) membranes were hydrothermally synthesized on pretreated surface of two common stainless steel materials, i.e., AISI 304 and 316L. XRD and SEM techniques were used to characterize the membranes. Various membrane morphologies can be obtained by adjusting synthesis conditions such as the H2O/SiO2ratio in the start colloid, the crystallization time and temperature as well as the substrate materials. The silicalite-1 membranes on the stainless steel surface show potential applications for regenerative fuel cooling technology in high speed flight field.

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44

Cruz-Navarro, Dalia Santa, Miguel Torres-Rodríguez, Violeta Mugica-Álvarez, and Mirella Gutiérrez-Arzaluz. "Separation and Capture of CO2 through A Zeolitic Membrane." Proceedings 2, no. 23 (November 12, 2018): 1436. http://dx.doi.org/10.3390/proceedings2231436.

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This paper presents the development and evaluation of a technology for CO2 separation and capture from a mixture of post-combustion gases through a zeolitic membrane. A silicalite-1 membrane was hydrothermally synthesized to selectively separate CO2 from a CO2/N2 mixture and permeation tests were performed on the mixture and the simple gases. The composition and morphology of the silicalite-1 crystals were confirmed by XRD and SEM/EDS. The recovered CO2 was used as raw material for its transformation into inorganic media like carbonates.

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45

Hong, Do-Young, Hyun Su Kim, Haoxiang Zhang, Su Kyung Kang, Elsa Tsegay Tikue, and Pyung Soo Lee. "Si–OH Nest and Al Distribution of Silicalite-1 Core/Al-ZSM-5 Shell Zeolites for Methane Dehydroaromatization Reaction." Crystals 11, no. 6 (June 8, 2021): 647. http://dx.doi.org/10.3390/cryst11060647.

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Silicalite-1 core/Al-ZSM-5 shell zeolite crystals were prepared in various sizes for use as catalysts in methane dehydroaromatization (MDA), and the growth kinetics and corresponding physicochemical properties of this core–shell zeolite were investigated. Al-ZSM-5 was grown on silicalite-1 seeds at various Si/Al ratios. Core–shell catalysts of all size variations exhibited similar deactivation trends in the MDA reaction, with minor changes in aromatic yields despite clear differences in reaction channel lengths and acid-site properties. This outcome was shown to originate from the unique growth kinetics of the Al-ZSM-5 layer on silicalite-1 seeds, in which the Al species in the sol used in the synthesis were consumed quickly during the early aggregative growth period. This led to an interesting spatial distribution of Al in the Al-ZSM-5 layer, in that the inner layer was relatively Al-rich. This distribution is advantageous because it can inhibit coke deactivation, which often occurs at the catalyst surface during MDA. However, a substantial quantity of Si–OH nests, which inhibit the effective loading of Mo species at the acid sites of the crystals, were detected in the microstructural analysis of large crystals. Therefore, this study shows that silicalite-1 core/Al-ZSM-5 shell zeolites can be prepared for use as coke-resistant catalysts for the MDA reaction. Further work is required, however, to design a synthesis method which reduces the number of Si–OH nests formed.

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46

Sánchez-Flores, N. A., M. Solache, M. T. Olguín, J. Legaspe, G. Pacheco-Malagón, J. M. Saniger, E. Martinez, S. Bulbulian, and J. J. Fripiat. "Silicalite-1, an adsorbent for 2-, 3-, and 4-chlorophenols." Water Science and Technology 66, no. 2 (July 1, 2012): 247–53. http://dx.doi.org/10.2166/wst.2012.073.

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The adsorption of the three chlorophenol isomers, ortho, meta and para, by silicalite-1 has been studied at 30 °C, below the solubility (at the same temperature) in water. Large differences, up to 30 times, have been observed between the adsorption of the para- vs. the ortho-isomer. The difference of behavior observed between the isomers is assigned to the tendency to self-organization of the para-isomer. It seems probable that the adsorption sites are at the intersection channels. From a technical point of view, silicalite-1 seems a competitive adsorbent for p-chlorophenol.

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47

Sakai, Motomu, Hayata Hori, and Masahiko Matsukata. "Self-defect-healing of silicalite-1 membrane in alkaline aqueous solution with surfactant." Materials Advances 2, no. 12 (2021): 3892–97. http://dx.doi.org/10.1039/d1ma00364j.

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48

Zhang, Yanfei, Lanjian Xu, Jie Zhang, Peidong Li, Yangyang Yuan, Hongchen Guo, Xiaomin Zhang, and Lei Xu. "Insight into the dissolution–crystallization strategy towards macro/meso/microporous Silicalite-1 zeolites and their performance in the Beckmann rearrangement of cyclohexanone oxime." Catalysis Science & Technology 8, no. 17 (2018): 4526–36. http://dx.doi.org/10.1039/c8cy00885j.

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49

Bhange, D. S., and Veda Ramaswamy. "Negative thermal expansion in silicalite-1 and zirconium silicalite-1 having MFI structure." Materials Research Bulletin 41, no. 7 (July 2006): 1392–402. http://dx.doi.org/10.1016/j.materresbull.2005.12.002.

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50

Gora, L. "Highly reproducible high-flux silicalite-1 membranes: optimization of silicalite-1 membrane preparation." Separation and Purification Technology 22-23, no. 1-2 (March 1, 2001): 223–29. http://dx.doi.org/10.1016/s1383-5866(00)00132-5.

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Journal articles on the topic 'Silicalite'

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