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1
Elysabeth, Tiur, Zulnovri, Gina Ramayanti, Setiadi und Slamet. „Modification of Lampung and Bayah Natural Zeolite to Enhance the Efficiency of Removal of Ammonia from Wastewater“. Asian Journal of Chemistry 31, Nr. 4 (27.02.2019): 873–78. http://dx.doi.org/10.14233/ajchem.2019.21810.
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In this research, modification of Lampung and Bayah natural zeolites was carried out to increase the zeolite’s capacity as an ammonia adsorbent. Natural zeolite is modified by acid treatment using 6 M HCl and ion exchange using 1 M NH4NO3. The modification process continued with calcination at 500 °C for 4 h. X-ray fluorescence characterization shows changes in composition in the modified zeolites. The significant increase in the Si/Al ratio occurred in the modified zeolite with acid treatment that is 10.03 for Lampung natural zeolite HCl (LNZH) and 9.20 for Bayah natural zeolite HCl (BNZH). Surface area increases due to increasing Si/Al ratio. FTIR results indicate changes in the intensity of hydroxyl groups and pyrH+ as a result of the increase in total acidity of zeolites. The zeolites performance test proves that the Bayah natural zeolite has a higher ammonia adsorption capacity than Lampung natural zeolite. Ion exchange-modified zeolite has a higher ammonia adsorption capacity than zeolite modified with acid treatment.
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Barbosa, Tellys Lins Almeida, und Meiry Gláucia Freire Rodrigues. „Synthesis of SAPO-34 Zeolite Membrane: Influence of Sources of Silica“. Catalysis Research 03, Nr. 04 (11.12.2023): 1–19. http://dx.doi.org/10.21926/cr.2304030.
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The research described the production and characterization of various materials, particularly alpha-alumina ceramic supports, zeolite SAPO-34, and zeolite membranes. Ceramic supports were manufactured through dry uniaxial compaction. Sintering of the supports was carried out at 1300°C for 2 h. SAPO-34 zeolites and zeolite membranes were synthesized through a hydrothermal process involving two steps: a first step at 38°C for 24 h and a second step at 200°C for 24 h. The research aimed to determine how different silica sources, namely Aerosil 380, colloidal silica, and TEOS, influenced the outcome of the synthesis. The study identified that Aerosil 380 silica was the most suitable source for synthesizing SAPO-34 zeolites and membranes. Zeolite membranes (SAPO-34/alpha-alumina) displayed a uniform and homogeneous distribution of SAPO-34 phase zeolitic crystals. The absence of defects or cracks in these membranes confirmed the successful formation of the SAPO-34 zeolite membrane structure. This research has significant implications, particularly in materials science and applications utilizing zeolites and membranes. The choice of silica source plays a crucial role in determining the quality and properties of the synthesized materials, and the detailed characterization provides valuable insights into their performance in practical applications. Overall, the research contributes to the understanding and optimization of zeolite synthesis processes.
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Nuhu, A. A., Z. N. Garba, H. Ibrahim und S. Abdulrazak. „Physicochemical Characterization of Zeolite Materials Produced from Selected Low-Cost Agricultural Wastes“. Journal of Applied Sciences and Environmental Management 28, Nr. 3 (27.03.2024): 675–80. http://dx.doi.org/10.4314/jasem.v28i3.7.
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Zeolites play a crucial role in adsorption processes for eliminating pollutants from industrial effluents and are extensively utilized in catalytic activities across diverse syntheses. This study focused on the conversion of three agricultural wastes—corncob, groundnut shell, and sugarcane bagasse—into zeolitic materials through three analytical methods: hydrothermal, microwave sintering, and alkali fusion, respectively. Standard methods were employed to assess the physicochemical parameters of the resulting zeolites. Generally, the produced zeolites had excellent surface areas and porosities. However, zeolites synthesized from sugarcane bagasse via the alkali fusion method exhibited highest porosity (80.9%), whereas that derived from corncob demonstrated highest surface area (1335 m2/g). Point of zero charge for the produced zeolites was within the range of 7.9-9.8, with zeolite produced from groundnut shells via alkali fusion having the highest value (9.8). The elevated porosities and surface areas, and point of zero charge of the synthesized zeolites signify their enhanced adsorptive capacity, implying their suitability for application as adsorbents for the removal of organic and inorganic pollutants. These findings underscore the effectiveness of synthesized zeolites in reducing or completely removing pollutants such as phenols, dyes, pesticides, heavy metals, and inorganic anions from wastewater.
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Hakiki, Muhammad, Muhammad Makiyi, Nuryoto Nuryoto, Rahmayetty Rahmayetty, Indar Kustiningsih und Teguh Kurniawan. „Pengaruh Lokasi Zeolit Alam Bayah terhadap Adsorpsi Amonium: Studi Kinetika dan Kesetimbangan“. Jurnal Teknologi Lingkungan 22, Nr. 1 (03.02.2021): 018–28. http://dx.doi.org/10.29122/jtl.v22i1.4403.
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ABSTRACT Household waste is one of the most significant contributors to wastewater that can pollute the environment, one of which is ammonium pollution. Ammonium pollution can be reduced by natural zeolite by using the adsorption method. This research aims to utilize natural zeolite as an adsorbent that can reduce ammonium levels in wastewater, determine which natural zeolite has the most significant adsorption power from 4 locations, determine natural zeolite characterization of Bayah. This study is also to create a model equilibrium equations and reaction kinetics from the adsorption method. The method used is the adsorption method, X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Brunauer-Emmett-Teller (BET). This study's results were that natural zeolites location 4 could adsorb 99.25% of ammonium and showed the highest adsorption capacity of ammonium. Characterization using XRD analysis obtained the types of zeolite mordenite, clinoptilolite, quartz, and heulandite. The surface area of Bayah natural zeolite in the 4th location is 46 m2/g. The suitable equilibrium model for the adsorption of ammonium by natural zeolites is the Freundlich model. The most suitable adsorption kinetics model for the adsorption of ammonium by Bayah natural zeolites is the pseudo-first-order model. Keywords: household waste, ammonium, eutrophication, natural zeolites ABSTRAK Limbah rumah tangga adalah salah satu penyumbang limbah cair terbesar yang dapat mencemari lingkungan salah satunya pencemaran amonium. Pencemaran amonium dapat dikurangi dengan zeolit alam dengan menggunakan metode adsorpsi. Tujuan dari penelitian ini adalah menentukan zeolit alam yang memiliki daya adsorpsi terbesar dari 4 lokasi berbeda, melakukan karakterisasi zeolit alam Bayah, dan memodelkan persamaan kesetimbangan dan kinetika reaksi adsorpsi amonium. Karakterisasi zeolit dilakukan dengan analisis X-ray diffraction (XRD), Scanning Electron Microsope (SEM), dan luas permukaan material menggunakan model Brunauer-Emmett-Teller (BET). Hasil dari penelitian ini adalah zeolit alam lokasi 4 memiliki kapasitas adsorpsi amonium paling besar, yaitu 9,25%. Adapun kapasitas adsorpsi amonium yang paling besar ditunjukkan oleh zeolit alam Bayah lokasi 4. Analisis XRD menunjukkan bahwa seluruh zeolit Bayah merupakan zeolit bertipe mordenit, klinoptilolit, dan heulandit dengan fasa pengotor quartz. Luas permukaan zeolit alam Bayah lokasi 4 sebesar 46 m2/g. Model kesetimbangan yang sesuai untuk adsorpsi amonium oleh zeolit alam Bayah yaitu model Freundlich. Model kinetika adsorpsi yang paling sesuai untuk adsorpsi amonium oleh zeolit alam Bayah yaitu model kuasi orde satu. Kata Kunci: limbah rumah tangga, amonium, eutrofikasi, zeolit alam
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Reschetilowski, Wladimir. „Catalysis on Zeolites and Zeolite-like Materials II“. Catalysts 14, Nr. 7 (17.07.2024): 460. http://dx.doi.org/10.3390/catal14070460.
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This Special Issue is a continuation of the previous successful Special Issue, “Catalysis on Zeolites and Zeolite-Like Materials”, which presented the latest developments and advances in the synthesis, characterization, and application of zeolites and zeolite-like materials as catalysts by renowned scientists [...]
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Intang, Ambo, Prahady Susmanto, Muhammad Djoni Bustan und Sri Haryati. „Characterization of Natural Zeolite Synthesized by Dealumination and Desilication Method“. Proceeding of the International Conference on Multidisciplinary Research for Sustainable Innovation 1 (12.08.2024): 10–18. http://dx.doi.org/10.31098/icmrsi.v1i.778.
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Delamination and desilication are two methods used in the hierarchical synthesis of zeolites. This process is important for industrial applications, particularly in synthesizing natural zeolites due to their abundance. For instance, Lampung, Indonesia, has abundant natural zeolites. The synthesis process of natural zeolite can be simplified using the solvent swelling mechanism. The swelling solvent mechanism combines the dealumination and desilication methods into one process, making it advantageous to use natural zeolites as raw materials for manufacturing hierarchical zeolites on an industrial scale. The sample used in this study was Natural Zeolite Lampung (NZL), and the resulting product was characterized as NZL Swelling. In this study, only two characterization analyses were selected to test the reliability of the dealumination and desilication methods simultaneously in one process, namely XRD and BET.
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Alsawalha, Murad. „Overview of Current and Future Perspectives of Saudi Arabian Natural Clinoptilolite Zeolite: A Case Review“. Journal of Chemistry 2019 (03.03.2019): 1–16. http://dx.doi.org/10.1155/2019/3153471.
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After a thorough review of existing studies of clinoptilolite zeolites, three areas for potential investigation of the Saudi Arabian zeolites were found. They are the characterizations, the catalytic activity, active sites, and uses of natural clinoptilolite zeolites. First, no analysis is available worldwide to compare the percentage weight of local zeolites with those sourced from other countries, nor does one exist for the establishment on the zeolite conversion of MBOH with water on acidic catalysts at lower temperatures. Secondly, a review of current literature on the topic revealed that basic and active sites of Saudi Arabian zeolites have yet to be examined. Future investigation of zeolite catalytic activity can be achieved by methyl butynol test reaction (MBOH) and absorption-desorption of ammonia. In the characterization of a range of international materials, the methyl butynol test reaction was utilized, including on natural zeolites, natural clays, and synthesized hydrotalcites. However, the catalytic performance of natural Saudi Arabian clinoptilolite zeolites by test reaction of MBOH conversion has not been yet investigated. Therefore, this article also includes an outline of the general testing conditions and parameters required to execute the accurate characterization of local Saudi clinoptilolite under optimal test conditions. Likewise, knowledge of the important active acidic centers of local materials is prescribed. This can be ascertained by determining the conditions together with the test parameters for the application of the “temperature-programmed desorption of ammonia” method in order to obtain an accurate determination of local Saudi clinoptilolite acidic centers. Additionally, an outline of the catalytic activity of worldwide clinoptilolite is given in this article together with kinetic investigations of other sources for the clinoptilolite zeolite in order to form the basis for the testing of local Saudi clinoptilolite. The percentage average of chemical composition (Wt.%) of natural clinoptilolite from various countries is also included. Finally, a future research plan is proposed here. This will form the basis for a complete study or survey to be compiled detailing the modifications needed to increase the surface areas for Saudi natural clinoptilolite zeolites using different methods of modifications. This could enhance its application as acid catalysts for use in the retardation of coke formation and for membrane separation on cationic exchange.
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Pan, M., P. A. Crozier, I. Y. Chan und S. I. Zones. „High-resolution electron microscopy on SSZ-26 zeolite materials“. Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 1032–33. http://dx.doi.org/10.1017/s0424820100089470.
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Zeolites constitute an important class of catalyst materials in the petrochemical industry. Zeolites are aluminosilicates with their framework structures made up of SiO4 (or AlO4) tetrahedra. The catalytic properties such as selectivity and activity are closely related to the structure sensitive properties of zeolites, e.g. shape selectivity, diffusivity, etc. Understanding these properties requires detailed structure characterization of the zeolites. High resolution electron microscopy (HREM) has been successfully applied to solve some zeolite structures when combined with experimental data from other techniques, e.g. absorption experiment. The connectivities of n-member rings in the zeolite frameworks can be directly deduced from the corresponding HREM images. However, radiation damage to the zeolite framework structures by the electron beam necessitates the use of low dose imaging techniques.
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Kamlesh Sahu. „STUDIES ON THE SYNTHESIS AND CHARACTERIZATION OF ZEOLITES AND THEIR APPLICATION AS A CATALYST“. International Journal for Research Publication and Seminar 15, Nr. 3 (18.09.2024): 357–64. http://dx.doi.org/10.36676/jrps.v15.i3.1518.
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Because of their wide range of uses in catalysis, adsorption, and ion exchange, zeolites, which belong to the family of microporous aluminosilicate minerals, have garnered a lot of interest in recent years. The synthesis and characterisation of a variety of zeolites, as well as their potential application as catalysts in certain industrial processes, are the primary objectives of this research. Following the hydrothermal synthesis of various zeolite structures, such as ZSM-5, Y-zeolite, and Beta-zeolite, using a variety of templates and raw materials, followed by the structural and chemical characterization of these zeolite structures using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR), the research is being conducted. In order to evaluate the effectiveness and selectivity of the produced zeolites in comparison to traditional catalysts, their catalytic activity is examined in a number of different processes, such as cracking, isomerization, and alkylation. The findings indicate that the particular pore structure, surface area, and acidity of the zeolites have a substantial impact on the catalytic activity of the zeolites. In addition, the catalytic capabilities of zeolites can be further improved by modifying them by ion exchange or impregnation with metal nanoparticles (for example, platinum or lead). After doing the research, the researchers came to the conclusion that zeolites have the potential to be effective catalysts for a variety of chemical transformations that are also kind to the environment. These catalysts are interesting alternatives to traditional catalysts in industrial processes such as the refinement of petrochemicals and the creation of sustainable energy because of their adaptability, the fact that their characteristics may be tuned, and the fact that they can be recycled.
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Bux, Nabi, Sadam Hussain Tumrani, Razium Ali Soomro und XiaodongJi. „Synthesis of Zeolites from Coal Fly Ash and Their Environmental Application“. International Journal of Economic and Environmental Geology 13, Nr. 2 (14.06.2022): 58–61. http://dx.doi.org/10.46660/ijeeg.v13i2.32.
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This study aims to make adsorption-capable zeolite from coal fly ash, a waste product from coal-fired power plants (CFA). When it comes to commercializing sorbent, the total cost and efficiency of the adsorbent material are critical. This work used tap water instead of distilled water (DW) to synthesis zeolite from fly ashes at 90°C crystallization temperatures. The discovery lays the door for a cost-effective but easy technique of synthesizing viable zeolitic materials for adsorption applications using waste products like coal fly ash. According to the comprehensive characterization, the support for the use of TP to make zeolites is based on its larger particle size, and lower carbon impurities. The generated zeolite was homogenous and A-type, and applied as an adsorbent to remove traces of heavy metals contaminants. During a 25-minute agitation period, the zeolites produced with TP had a greater adsorption capacity. In principle, the proposed approach permits the synthesis of low-cost, high-efficiency zeolite-based adsorbent materials for environmental remediation without the use of harmful or expensive chemicals.
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Hudec, P., J. Novanský, S. Silhár, T. N. Trung, M. Zúbek und J. Maďar. „Possibility of Using t-Plots, Obtained from Nitrogen Adsorption for the Valuation of Zeolites“. Adsorption Science & Technology 3, Nr. 3 (September 1986): 159–66. http://dx.doi.org/10.1177/026361748600300305.
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Data of adsorption isotherms of nitrogen adsorption at 77 K on various samples of zeolites were measured. Besides derivation of specific surface area by BET analysis, samples were characterised by values obtained by t-plots; specific surface areas of mesopores and specific volumes of micropores are also calculated. Results show the value of the use of t-plot method for the characterization of microporosity changes in zeolites after various treatments, and also for quantitative estimation of zeolite content in natural zeolites and the crystallinity of synthetic zeolites.
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Cadar, Oana, Irina Vagner, Ion Miu, Daniela Scurtu und Marin Senila. „Preparation, Characterization, and Performance of Natural Zeolites as Alternative Materials for Beer Filtration“. Materials 16, Nr. 5 (25.02.2023): 1914. http://dx.doi.org/10.3390/ma16051914.
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The clarity of the beer is essential to its marketability and good consumer approval. Moreover, the beer filtration aims to remove the unwanted constituents that cause beer haze formation. Natural zeolite, an inexpensive and widespread material, was tested as a substitute filter media for diatomaceous earth in removing the haze constituents in beer. The zeolitic tuff samples were collected from two quarries in Northern Romania: Chilioara, in which the zeolitic tuff has a clinoptilolite content of about 65%, and the Valea Pomilor quarry, containing zeolitic tuff with a clinoptilolite content of about 40%. Two-grain sizes, <40 and <100 µm, from each quarry were prepared and thermally treated at 450 °C in order to improve their adsorption properties and remove organic compounds and for physico-chemical characterization. The prepared zeolites were used for beer filtration in different mixtures with commercial filter aids (DIF BO and CBL3) in laboratory-scale experiments, and the filtered beer was characterized in terms of pH, turbidity, color, taste, flavor, and concentrations of the major and trace elements. The results showed that the taste, flavor, and pH of the filtered beer were generally not affected by filtration, while turbidity and color decreased with an increase in the zeolite content used in the filtration. The concentrations of Na and Mg in the beer were not significantly altered by filtration; Ca and K slowly increased, while Cd and Co were below the limits of quantification. Our results show that natural zeolites are promising aids for beer filtration and can be readily substituted for diatomaceous earth without significant changes in brewery industry process equipment and protocols for preparation.
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Tawachkultanadilok, Pimrapus, Nattawut Osakoo, Chalermpan Keawkumay, Krittanun Deekamwong, Narongrit Sosa, Catleya Rojviriya, Supinya Nijpanich, Narong Chanlek, Sanchai Prayoonpokarach und Jatuporn Wittayakun. „Synthesis and Characterization of Zeolite NaY Dispersed on Bamboo Wood“. Materials 16, Nr. 14 (11.07.2023): 4946. http://dx.doi.org/10.3390/ma16144946.
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Zeolites in powder form have the potential to agglomerate, lowering access to active sites. Furthermore, a suspension of fine zeolite powder in liquid media is difficult to separate. Such drawbacks could be improved by dispersing zeolite crystals on support materials. This work demonstrates the dispersion of zeolite NaY crystals on bamboo wood by mixing the wood with zeolite gel before hydrothermal treatment. The syntheses were performed with acid-refluxed and non–refluxed wood. The phase of zeolites, particle distribution and morphology, zeolite content in the wood, and zeolite–wood interaction were investigated using X-ray diffraction, X-ray tomography, scanning electron microscopy, thermogravimetric analysis, nitrogen sorption analysis, and X-ray photoelectron spectroscopy. Higher zeolite content and better particle dispersion were obtained in the synthesis with the acid–refluxed wood. The composite of NaY on the acid-refluxed wood was demonstrated to be an effective adsorbent for Ni(II) ions in aqueous solutions, providing a higher adsorbed amount of Ni(II) per weight of NaY.
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Gil-Muñoz, Gema, Juan Alcañiz-Monge und María José Illán-Gómez. „Analyzing the Effect of Zr, W, and V Isomorph Framework Substitution on ZSM-5 and Beta Zeolites for Their Use as Hydrocarbon Trap“. Molecules 28, Nr. 12 (13.06.2023): 4729. http://dx.doi.org/10.3390/molecules28124729.
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This work evaluates the effect on the adsorption and desorption kinetics of propene and toluene (used as probe molecules for vehicle cold-start emissions) of the isomorph framework substitution of Zr, W, and V on commercial ZSM-5 and beta zeolites. TG-DTA and XRD characterization data indicated that: (i) Zr does not modify the crystalline structure of the parent zeolites, (ii) W develops a new crystalline phase, and (iii) V causes the breakdown of the zeolite structure during the aging step. The CO2 and N2 adsorption data revealed that the substituted zeolites present a narrower microporosity than pristine zeolites. As a consequence of all these modifications, the modified zeolites feature different adsorption capacity and kinetics of HCs, so, different hydrocarbon trapping ability than pristine zeolites. However, a clear correlation is not observed between the changes in the porosity/acidity of zeolites and the adsorption capacity and kinetics, which depends on: (i) the zeolite (ZSM-5 or BEA), (ii) the hydrocarbon (toluene or propene), and (iii) the cation to be inserted (Zr, W, or V).
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Solihat, Imas, Lilis Sulistiawaty, Putri Hawa Syaifie und Agus Taufiq. „Removal of Cu Metals from Wastewater by Adsorption using Synthetic Zeolites from Rice Husk and Corncob“. Molekul 15, Nr. 2 (27.07.2020): 105. http://dx.doi.org/10.20884/1.jm.2020.15.2.589.
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Heavy metals, such as Cu, are hazardous components so that it needs to reduce their concentration due to their negative impact on the environment. One method that can be used to reduce heavy metals in waste is to use adsorbents (synthetic zeolites). Utilization of agricultural waste such as rice husks and corncobs as precursors of synthetic zeolites will add economic value because it is relatively cheap with a lot of availability. This research aimed to find out new variants of synthetic zeolites, which can reduce the concentration of Cu in the adsorption process. The study consisted of 3 stages, the first stage was zeolite synthesis by the sol-gel method with 3 zeolite variants (A, B and C), the second stage was characterization using XRD and SEM, and the third stage was zeolites optimization (variations in pH, weight, and concentration). According to the results of SEM, zeolite B had a larger and uniform pore size so as it produced a greater adsorption capacity (4.82 mg/g) to be compared with zeolites A and C. The results showed synthetic zeolite C was able to adsorb Cu waste by following the adsorption isotherm model of Langmuir
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Coughlan, Brendan, und Mark A. Keane. „A characterization and catalytic study of Y zeolite supported Ni/Cu bimetallics“. Canadian Journal of Chemistry 68, Nr. 9 (01.09.1990): 1471–76. http://dx.doi.org/10.1139/v90-225.
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A wide range of CuNiNaY andCuNiKY zeolites were prepared by ion exchange. The location of both Ni2+ and Cu2+ cations within the zeolite framework was monitored after various stages of thermal treatment and the reduction process of the transition metal ions in a flowing hydrogen atmosphere was investigated and correlated with reduction time and temperature. The metallic phase generated on reduction was characterized by X-ray diffraction line broadening. The catalytic activity of the reduced zeolites in the hydrogenation of benzene is discussed in the light of these physical characterizations.Keywords: zeolites, supported Ni/Cu bimetals, cation location, crystallite size, catalysis.
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Akinruli, Ifedayo Joshua, Seun Samuel Owoeye, Segun Michael Abegunde, Ayodeji E. Onipede und Ukoba Kingsley. „Synthesis and Characterization of NaA Zeolite Using Natural Kaolinite Clays from Nigeria by Low Temperature Hydrothermal Method“. International Journal of Research in Engineering, Science and Management 4, Nr. 2 (13.02.2021): 40–47. http://dx.doi.org/10.47607/ijresm.2021.498.
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Zeolites NaA is one of the most valuable synthetic zeolites widely used as ion-exchange material, catalysts, and adsorbents in industry. There is therefore need to adopt a more energy-efficient route for its synthesis from low-cost and sustainable raw materials. In this present work, zeolites Na-A was synthesized from natural kaolinite clays obtained from three selected regions (Ikere, Okpella and Kankara) in Nigeria. The as-received kaolinite clays (IKclay, OKclay and KAclay) were initially beneficiated thoroughly to obtain pure powders (˂75 μm). The processed kaolinite clay powders were then subjected to heating in a muffle furnace at 850oC for 3 h at a heating rate of 10oC/min to convert the kaolinite clays to their respective metakaolins. The obtained metakaolins were then reacted with NaOH solutions at varying concentrations of 3.0 and 4.0M respectively using a low temperature hydrothermal transformation to obtained Zeolites Na-A powders. The obtained zeolites were then analyzed by scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FT-IR). The results showed that zeolite NaA is produced with mixture of hydroxysodalite (HS) while the EDS revealed the presence of Si, Al, O and Na indicating chemical constituents of typical zeolite NaA. All the tested kaolinite clays are therefore suitable for preparation of zeolite NaA as cheaper source of silica and aluminum.
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Kamal, Sanarya K., und Ammar S. Abbas. „Textural Properties Characterization for NaX and FeX Zeolites by Nitrogen Adsorption-desorption Technique“. Iraqi Journal of Chemical and Petroleum Engineering 23, Nr. 4 (30.12.2022): 33–41. http://dx.doi.org/10.31699/ijcpe.2022.4.5.
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The zeolite's textural properties have a significant effect on zeolite's effectiveness in the different industrial processes. This research aimed to study the textual properties of the NaX and FeX zeolites using the nitrogen adsorption-desorption technique at a constant low temperature. According to the International Union of Pure and Applied Chemistry, the adsorption-desorption isotherm showed that the studied materials were mixed kinds I/II isotherms and H3 type hysteresis. The Brunauer-Emmett-Teller isotherm was the best model to describe the nitrogen adsorption-desorption better than the Langmuir and Freundlich isotherms. The obtained adsorption capacity and Brunauer-Emmett-Teller surface area values for NaX were greater than FeX. According to the Kelvin equation, Barrett, Joyner, and Halenda model was used to determine pore size distribution, diameter, and average pore volume for the selected zeolites. The pore size distribution for NaX was wider than FeX zeolites, the pore diameter for NaX was less than FeX, and the average pore volume for FeX was greater than the value of NaX average pore volume. The comparative study was carried out with the previous studies, and the comparison showed that the textual properties of the modified zeolites agreed with other studies.
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Yee, Maxine, und Iskandar I. Yaacob. „Synthesis and Characterization of Iron Oxide Nanostructured Particles in Na–Y Zeolite Matrix“. Journal of Materials Research 19, Nr. 3 (März 2004): 930–36. http://dx.doi.org/10.1557/jmr.2004.19.3.930.
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Formation of iron oxide nanoparticles within the internal cages of Na–Y zeolites was investigated. Sodium ions within the zeolites were replaced with iron(II) ions. Elemental composition studies showed a significant amount of iron in the exchanged sample. NaOH and dropwise additions of H2O2 at 60 °C triggered formation of zeolite–iron oxide systems. X-ray diffraction (XRD) patterns showed diminishing zeolite peaks along with evolution of peaks corresponding to γ-Fe2O3 and α-Fe2O3 with increasing NaOH concentration. Morphological changes from hexagonal-shaped zeolite to clusters of fine particles were observed under scanning electron microscope. Particles with about 15-nm diameter were detected by transmission electron microscopy. γ-Fe2O3 crystallites of 13.4 nm were determined from the broadening of XRD peaks. The magnetization curves of samples (precipitated using NaOH with concentrations of 2.0 M and above) showed absence of hysteresis and passed through the origin, indicating the particles are superparamagnetic. Gas adsorption–desorption measurement of the system precipitated with 2.0 M NaOH revealed a 26% increase in its specific surface area, indicating the presence of nanometer-sized particles within the zeolites.
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Gackowski, Mariusz, und Jerzy Datka. „Acid Properties of Hierarchical Zeolites Y“. Molecules 25, Nr. 5 (26.02.2020): 1044. http://dx.doi.org/10.3390/molecules25051044.
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The article reviews different strategies towards obtaining mesoporous zeolites Y: desilication; surfactant templating and assembly of zeolite crystals. The impact of those methods on physicochemical properties is covered, with a special focus on the acidity of the samples measured with infrared (IR) spectroscopy. The methods of characterization of acidity are presented. Quaternary ammonium cations used for desilication lead to obtaining crystalline; mesoporous and highly acidic zeolites. Si-OH-Al groups of extremely high acidity can be produced by calcination in a humid atmosphere. When the conditions are optimized, post-synthetic surfactant templating allows crystalline mesoporous zeolite to be obtained with no loss of material. All mesoporous zeolites Y proved to be active catalysts in liquid phase isomerization, catalytic cracking, and other reactions.
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Kiradzhiyska, Denitsa, Tsvetelina Batsalova, Balik Dzhambazov, Nikolina Milcheva, Kiril Gavazov, Nikolay Zahariev, Georgi Avdeev und Stanislava Simeonova. „Synthesis, Characterization, and Cytotoxicity Evaluations of Silver–Zeolite Nanocomposite“. Coatings 14, Nr. 6 (29.05.2024): 681. http://dx.doi.org/10.3390/coatings14060681.
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Zeolites of natural origin are materials exhibiting many positive effects on the human body. Silver-modified zeolites have already been introduced as bactericidal agents, although studies dealing with their toxicity are insufficient. This work describes the synthesis of activated and silver-loaded Bulgarian zeolite using a simple wet impregnation method. Morphological characteristics and compositions of natural zeolite, activated zeolite, and Ag-nanocomposites were studied by the X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. Silver loading is approximately 13 wt. %, with mean Ag particle size around 19 nm. Analyses of the samples included antioxidant activity assays based on ABTS radical scavenging ability and in vitro cytotoxicity tests with human normal fibroblasts and three adenocarcinoma cell lines. The experiments were performed with natural, activated, and Ag-modified zeolite in comparison to two commercial food supplements. Our results indicated moderate antioxidant activity of the tested samples. Silver-modified zeolite demonstrated cytotoxic effects against both tumor cells and normal fibroblasts, but the detected levels of inhibition were stronger against the adenocarcinoma cells, suggesting anti-tumor potential. The present article indicates a new aspect of Bulgarian natural zeolite and Ag-loaded zeolite biological activity. It highlights the need for detailed toxicity evaluations of Ag-nanocomposites prior to healthcare applications.
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Gómez-Castillo, R., P. Del Angel-Vicente und J. M. Domínguez-Esquivel. „High-resolution characterization of zeolites“. Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 778–79. http://dx.doi.org/10.1017/s0424820100145236.
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Structural variations such as microdefects, symmetry changes and crystalline intergrowths might influence the catalytic and chemisorptive properties of zeolites. Those variations occur at a very local scale, making it that traditional x-ray diffraction techniques are unsuitable to detect them. The alternative methods are high resolution electron microscopy and solid state- NMR.The HREM images obtained in the microscope are influenced by instabilites of the zeolite crystals, beam damage, electronoptical parameters and other dynamical interactions, which add each other to produce a rather complex picture. Thus, the correct interpretation of results requires the determination of pa rameters, i.e. defocus, resolution level, astigmatism, etc.; together with the calculation of images, i.e. through Multislice methods.
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Ibsaine, Fatima, Dariush Azizi, Justine Dionne, Lan Huong Tran, Lucie Coudert, Louis-César Pasquier und Jean-François Blais. „Conversion of Aluminosilicate Residue Generated from Lithium Extraction Process to NaX Zeolite“. Minerals 13, Nr. 12 (22.11.2023): 1467. http://dx.doi.org/10.3390/min13121467.
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The production of lithium from spodumene ores generates huge amounts of residues mainly composed of aluminosilicates. The main objective of the present study was to synthesize NaX zeolites with good ion-exchange capacity from these aluminosilicate residues, without using the fusion step or chemically modifying their initial Si/Al ratio. A physico-chemical (chemical composition, sorption capacity) and mineralogical (XRD, SEM) characterization of the zeolite synthesized using the conventional hydrothermal process (Process_1) was performed and compared with zeolite produced using a fusion step followed by a hydrothermal treatment process (Process_2) and commercial zeolite 13X. Then, the effect of operating parameters such as aging time and temperature, crystallization time and solid/liquid ratio on the sorption capacities of the synthesized zeolites using the conventional hydrothermal process was assessed. Initial aluminosilicate residues were mainly composed of Al2O3 (24.6%) and SiO2 (74.0%), while containing low amounts of potential contaminants (<1.6%). Based on its chemical composition, the fine fraction (<53 µm) was identified as the most suitable fraction to produce zeolites, while coarser fractions which contained higher Li content can be used to produce glass and ceramics. Physico-chemical and mineralogical characterization results show that zeolite produced using the conventional hydrothermal process (Process_1) had similar properties compared to zeolites 13X. Therefore, Process_1 was identified as the most performant while reducing operating costs related to alkaline fusion pre-treatments, which did not significantly improve zeolite properties. Finally, the optimum conditions for converting the residues into zeolite NaX, which had an ion-exchange capacity of 58 mg Ca/g were 8 h of aging at 75 °C and 16 h of crystallization at 100 °C, with a solid/liquid ratio of 1/10 (w/v).
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Al Muhammadi, N. A. S., und A. Hussin. „Physical and mineral characterisation of natural zeolites from Taiz, South-western Yemen“. Journal of Environmental Biology 42, Nr. 3(SI) (31.05.2021): 744–49. http://dx.doi.org/10.22438/jeb/42/3(si)/jeb-02.
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Aim: To investigate the physical, minerals and geochemical composition of Taiz natural zeolites. Methodology: Each zeolite sample were assessed for its characterization via optical microscopy, X-ray Diffraction (XRD) techniques, X-ray Fluorescence Methods (XRF), Inductively Coupled Plasma- Optical Emission Spectrometry (ICP-OES) to examine their mineral composition and geochemistry properties. Further, physical properties like pH, electrical conductivity (EC), plasticity, specific surface area, water content and brightness were estimated by standard methods. Results: Natural zeolite in the studied area occurs within pyroclast of volcanic tuffs. It consists mainly of perlite and rhyolite as lenses grey to light green in color with fine granulation texture. Petrography analysis showed that the Taiz zeolites are mainly classified as clinoptilolite – heulandite and are mixed with various types of others zeolite minerals such as analcime, chabazite and mazzite. Small amounts of impurities like K-.feldspar (orthoclase) and clay mineral such as montmorillonite, kaolinite and illite were also detected. The mean ratio of SiO2:Al2O3 for representative zeolite sample from the study area ranged between of 6.34-6.98. Interpretation: Zeolites showed fairly medium to high brightness and on comparing with the commercial zeolites, Taiz zeolite showed significant industrial potential to be used as a filler in paper industry.
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Mauer, Volker, Christian Bläker, Christoph Pasel und Dieter Bathen. „Energetic Characterization of Faujasite Zeolites Using a Sensor Gas Calorimeter“. Catalysts 11, Nr. 1 (12.01.2021): 98. http://dx.doi.org/10.3390/catal11010098.
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In addition to the adsorption mechanism, the heat released during exothermic adsorption influences the chemical reactions that follow during heterogeneous catalysis. Both steps depend on the structure and surface chemistry of the catalyst. An example of a typical catalyst is the faujasite zeolite. For faujasite zeolites, the influence of the Si/Al ratio and the number of Na+ and Ca2+ cations on the heat of adsorption was therefore investigated in a systematic study. A comparison between a NaX (Sodium type X faujasite) and a NaY (Sodium type Y faujasite) zeolite reveals that a higher Si/Al ratio and therefore a smaller number of the cations in faujasite zeolites leads to lower loadings and heats. The exchange of Na+ cations for Ca2+ cations also has an influence on the adsorption process. Loadings and heats first decrease slightly at a low degree of exchange and increase significantly with higher calcium contents. If stronger interactions are required for heterogeneous catalysis, then the CaNaX zeolites must have a degree of exchange above 53%. The energetic contributions show that the highest-quality adsorption sites III and III’ make a contribution to the load-dependent heat of adsorption, which is about 1.4 times (site III) and about 1.8 times (site III’) larger than that of adsorption site II.
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An, Hyejin, Sungjoon Kweon, Sanggil Park, Jaeyoung Lee, Hyung-Ki Min und Min Bum Park. „Immobilization of Radioiodine via an Interzeolite Transformation to Iodosodalite“. Nanomaterials 10, Nr. 11 (29.10.2020): 2157. http://dx.doi.org/10.3390/nano10112157.
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We described a technology for immobilizing radioiodine in the sod-cages by the interzeolite transformation of iodine-containing LTA (zeolite A) and FAU (zeolites X and Y) into a sodalite (SOD) structure. The immobilization of iodine in the sod-cage was confirmed using diverse characterization methods including powder XRD, elemental analysis, SEM–EDS, 127I MAS NMR, and I 3d XPS. Although both zeolites A (Na-A) and X (Na-X) were well converted into SOD structure in the presence of NaI and AgI, the iodide anions were fixed in the sod-cages only when NaI was used. The ability to adsorb methyl iodide (CH3I) was evaluated for zeolites A and X in which Na+ and/or Ag+ ions were exchanged, and Ag+ and zeolite X showed better adsorption properties than Na+ and zeolite A, respectively. However, when both CH3I adsorption ability and the successive immobilization of iodine by interzeolite transformation were considered, Na-X was determined to be the best candidate of adsorbent among the studied zeolites. More than 98% of the iodine was successfully immobilized in the sod-cage in the SOD structure by the interconversion of Na-X following CH3I adsorption, although the Na-X zeolite exhibited half the CH3I adsorption capacity of Ag-X.
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Zandbergen, H. W., und D. van Dyck. „High Resolution Electron Microscopy on zeolites“. Proceedings, annual meeting, Electron Microscopy Society of America 48, Nr. 4 (August 1990): 290–91. http://dx.doi.org/10.1017/s0424820100174588.
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Zeolites are very suitable for high-resolution electron microscopical investigation since their pore structure often allows an unambiguous interpretation of the images, especially when taken with the electron beam parallel to one of the pore channel direction. HREM can give very useful information on a number of subjects of major importance in zeolite synthesis a.Nucleation;b.Defect characterization;c.Characterization of growth mechanisms of denser phases;d.Structure determination;e.Identification of small metal particles inside the zeolite matrix.f.Structural changes due to (catalytic) reactions.
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Ruíz-Baltazar, Alvaro, Rodrigo Esparza, Maykel Gonzalez, Gerardo Rosas und Ramiro Pérez. „Preparation and Characterization of Natural Zeolite Modified with Iron Nanoparticles“. Journal of Nanomaterials 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/364763.
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This study is aimed at investigating the structural and morphological characterization of natural and modified zeolite obtained from the state of Oaxaca (Mexico). Iron nanoparticles were used for the zeolite modification. The iron nanoparticles were loaded on the zeolite surface by homogeneous nucleation. Adsorption kinetic models of pseudo first and second order were surveyed. The characterization of pristine and modified zeolite was performed by Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). From the results, three main phases were identified: clinoptilolite, mordenite, and feldspar. We could also determine the adsorption capacity of the zeolites by means of adsorption kinetic models.
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Kasic, Vladan, Slavica Mihajlovic, Dragana Zivotic, Vladimir Simic, Jovica Stojanovic, Zivko Sekulic und Milan Kragovic. „Characterization of the zeolitic tuff from the “Igros-Vidojevici” deposit regarding geological and technological aspects“. Chemical Industry 72, Nr. 1 (2018): 29–37. http://dx.doi.org/10.2298/hemind170428015k.
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This study presents investigations of zeolitic tuff samples from the ?Igros- -Vidojevici? deposit. The aim of the research was to determine the quality of samples taken from all deposit parts. Thus, samples were taken from the footwall (?Zeolit 1?), and four samples from the central deposit part (?Zeolit 2?, ?Zeolit 3?, ?Zeolit 4? and ?Zeolit 5?). Characterization of the samples included chemical analysis, determination of the adsorption coefficient for methylene blue dye and cation-exchange capacity (CEC), X-ray powder diffraction analysis (XRPD), differential thermal and thermogravimetric analysis (DTA and TGA), and Fourier transform Infrared spectroscopic analysis (FTIR). Results have shown that the footwall consists mostly of clays, whereas zeolite minerals dominate in the rest of the deposit. XRD analysis of the ?Zeolit 1? sample confirmed presence of smectite and kaolinite clays, while zeolite of analcime type and quartz are present as smaller fractions. Chemical composition analysis and determination of heavy metal contents showed a significant amount (7.58%) of Fe2O3 in this sample. Therefore, further research can be pursued to find a method for removal of magnetic impurities in this deposit portion in order to utilize the clay fraction. On the other hand, according to XRD, FTIR, DTA/TGA and SEM/EDS analyses, samples which belong to the central deposit part (?Zeolit 2?5?) consist of clinoptilolite zeolite type, while clays are present in less than 10%. Thus, clays (smectites and kaolinite) accompanied with analcime and quartz are the most abundant footwall minerals while central deposit parts contain predominantly clinoptilolite accompanied with small amounts of clays. Mineragenetically, zeolites are most abundant in the ?Zeolit 2? and ?Zeolit 3? samples. The smallest value of CEC was determined for the ?Zeolit 1? sample (46.98 mmol/100g). According to CEC values determined for ?Zeolit 2? and ?Zeolit 3? (141.99 and 121.01 mmol/100 g, respectively) these samples are of the best quality, and could be utilized as adsorbents of inorganic pollutants from contaminated waters. Moreover, they could be potentially used for removal of mycotoxins from cattle feed. ?Zeolit 4? and ?Zeolit 5? samples have shown slightly lower CEC values (89.48 and 83.75 mmol/100 g, respectively), which implies lower quality, and, therefore, could be used for soil quality improvement. Finally, determination of the external CEC has revealed a significant difference between ?Zeolit 1? and ?Zeolit 5? samples (17.9 and 5.31 mmol/100 g, respectively).
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Padilla, Jessyka, und Verónica García. „Preparation and Characterization of ZSM-5 Zeolites Modified with Titanium and Iron by Direct Synthesis“. MRS Proceedings 1765 (2015): 145–51. http://dx.doi.org/10.1557/opl.2015.821.
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ABSTRACTThe research for new energy sources has promoted hydrocarbon production from biomass and solid wastes over ZSM-5 zeolites. The metal incorporation by different methods has led to a variety of chemical applications. In this way, the combination of the shape selectivity and acidity properties of the pentasil zeolites with the activity of metal oxide under different environments may influence the product distribution in diverse catalytic reactions. In this work, ZSM-5 zeolites were prepared by hydrothermal synthesis employing aluminum nitrate and AIP as aluminium sources and TPAOH as structure director agent at atmospheric pressure and low temperature (90 °C). In addition, these materials were modified with iron and titanium cations by direct synthesis at 170 °C and autogenous pressure to promote the crystallinity. The characterization of the samples was performed by XRD, XRF, SEM, TPD-NH3 and nitrogen adsorption. It was observed that the use of AIP and the metal incorporation decreases the crystallinity of the zeolites under synthesis conditions, which leads to increase the specific area value in the BET because of the presence of amorphous material. On the other hand, acidity of the modified zeolites was found to be lower than that of ZSM-5 zeolite.
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Vokhmintsev, Andrei P. „Ektacytometry: Characterization of erythrocytes of residents of KhMAO-Yugra treated with natural zeolites“. Izvestiya of Saratov University. Chemistry. Biology. Ecology 24, Nr. 4 (18.12.2024): 461–72. https://doi.org/10.18500/1816-9775-2024-24-4-461-472.
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The effect of a diet containing natural zeolite (clinoptilolite) on the deformability of red blood cells of volunteers of both sexes, of a wide age range living in KhMAO-Yugra (Khanty-Mansiysk), was studied. Natural zeolites, according to literature data, have antioxidant, membrane-protective and hematostimulating properties. It has been shown that the use of zeolite powder by volunteers for 30 days causes an increase in the erythrocyte deformability index (determined by laser diffractometry) compared to measurements taken before the start of the study. Such changes were the result of a significant increase in erythropoiesis and a decrease in lipoperoxidation processes. The results obtained indicate the multifaceted role of zeolites in ensuring the normal functioning of the human body living in areas with uncomfortable climatic and geographical conditions.
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Zhou, Jian, Ni Zhang, Tao Meng, Qiangsheng Guo, Zhaoteng Xue und Dongsen Mao. „Fluoride-Treated Nano-HZSM-5 Zeolite as a Highly Stable Catalyst for the Conversion of Bioethanol to Propylene“. Nanomaterials 14, Nr. 19 (26.09.2024): 1558. http://dx.doi.org/10.3390/nano14191558.
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Fluoride treatment of ZSM-5 zeolite can effectively adjust surface acidity and generate a secondary pore structure. In this study, a series of modified nano-HZSM-5 zeolites were prepared by NH4F-HF mixed solution treatment and applied to the selective conversion of bioethanol to propylene at 500 °C, atmospheric pressure, and a WHSV of 10 h−1. The results showed that NH4F-HF modification weakened the surface acidity of nano-HZSM-5 zeolites, thus inhibiting coke formation. Additionally, the mesopores in the nano-HZSM-5 zeolites increased after NH4F-HF treatment, thereby enhancing the mass transfer rate and improving the coke-resistance ability. The NH4F-HF mixed solution modification significantly improved the stability of nano-HZSM-5 zeolites in catalyzing bioethanol to propylene and greatly extended the working life of nano-HZSM-5 zeolites. It can be seen from the characterization of the deactivated catalysts that coke deposition and weakening of acidity may be the key factors for catalyst deactivation.
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Purnamaningsih, Nur'aini, Endah Retnaningrum und Wahyu Wilopo. „PEMANFATAAN KONSORSIUM BAKTERI PEREDUKSI SULFAT DAN ZEOLIT ALAM DALAM PENGENDAPAN LOGAM Mn“. Jurnal Penelitian Saintek 22, Nr. 1 (28.08.2017): 37. http://dx.doi.org/10.21831/jps.v22i1.15311.
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Tujuan dari penelitian ini adalah untuk mengetahui pengaruh penambahan zeolit alam Wonosari terhadap aktivitas Bakteri Pereduksi Sulfat dalam pengendapan logam Mn skala continous culture dan mengidentifikasi karakter biofilm Bakteri Pereduksi Sulfat oleh aktivitas konsorsium Bakteri Pereduksi Sulfat pada zeolit alam dalam skala continous culture. Tahap penelitian meliputi aktivasi zeolit, pengujian aktivitas konsorsium Bakteri Pereduksi Sulfat dalam skala continous culture; serta karakterisasi biofilm konsorsium Bakteri Pereduksi Sulfat. Konsorsium Bakteri Pereduksi Sulfat yang digunakan berasal dari kotoran kambing. Zeolit yang digunakan pada pengujian aktivitas konsorsium Bakteri Pereduksi Sulfat adalah zeolit alam Wonosari yang berukuran 0,8-1,2 cm. Hasil penelitian menunjukkan bahwa konsorsium Bakteri Pereduksi Sulfat pada bioreaktor dengan penambahan zeolit mempunyai aktivitas yang lebih efektif dibandingkan dengan bioreaktor tanpa penambahan zeolit, dimana pH meningkat menjadi pH 6,9; efisiensi pengendapan logam Mn sebesar 61,16%, serta nilai MPN yang lebih tinggi. Zeolit dalam bioreaktor dengan waktu pembentukan biofilm 5 hari dan 9 hari terlihat adanya biofilm konsorsium Bakteri Pereduksi Sulfat yang tumbuh melekat pada permukaan zeolit. The objective of this study were determining the effects of natural zeolite from Wonosari on the activites of Sulfate Reducing Bacteria in Mangan (Mn) sedimentation of continous culture scale, and identifying the biofilm character of Sulfate Reducing Bacteria on consortium activites on natural zeolite using continous culture scale. The first studies was activation of zeolites, followed by testing the activity of consortium activities of Sulfate Reduction Bacteria in continuous culture scales; and biofilm characterization of Sulfate Reducing Bacteria consortium. The consortium of Sulfate Reducing Bacteria derived from goat feces. The size of zeo natural zeolites used in the consortium activity test of Sulfate Reducing Bacteria in Mangan sedimentation was 0.8 to 1.2 cm. The results showed that the consortium of Sulfate Reducing Bacteria in the bioreactor with the addition of zeolite had an activity that was more effective than the bioreactor without the addition of zeolite, where the pH was increased to pH 6.9; Mangan sedimentation was 61,16%, and the higher MPN index. Zeolite in a bioreactor with biofilm formation in 5th days and 9th days seems that there were biofilm consortium of Sulfate Reducing Bacteria growing attached to the surface of the zeolite.
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Mukti, Rino R., Shofarul Wustoni, Agus Wahyudi und Ismunandar Ismunandar. „CONVERSION OF THE LOW QUALITY INDONESIAN NATURALLY-OCCURRING MINERALS INTO SELECTIVE TYPE OF ZEOLITES BY SEED-ASSISTED SYNTHESIS METHOD“. Indonesian Journal of Chemistry 13, Nr. 3 (18.12.2013): 278–82. http://dx.doi.org/10.22146/ijc.21288.
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An X-ray diffraction (XRD) revealed that Indonesian naturally-occurring mineral from Nanggung, Bogor shows to be a low quality product as it does not seem to contain any zeolite materials. As located in the volcanic area, Indonesia essentially has abundant source of natural zeolites and the country has put much efforts on these treasured materials for export commodity. In order to bring the local natural mineral into high value and to discover whether the mineral has at least zeolitic fragments, we have implemented seed-assisted synthesis to see the possibility of growing zeolite and turn this mineral into high quality. In principle, once the mineral has zeolitic fragment or nuclei, recrystallization of the mineral may occur. By utilizing this mineral as seed in aluminosilicate mother solution, selective mordenite-type (MOR) zeolite can be obtained after hydrothermal treatment. Characterization by XRD showed that this MOR zeolite has high crystallinity and scanning electron microscopy (SEM) depicted the crystal morphology. The natural mineral is conclusively essential for the formation of MOR zeolite by seeding the aluminosilicate mother solution. In the absence of aluminosilicate mother solution, natural mineral can be recrystallized into selective analcime-type (ANA) zeolite. MOR zeolite is known to be useful for several applications such as catalysis whereas ANA zeolite has been considered to be less potential due to relatively small microporosity.
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Kurniawan, Teguh, Nuryoto und Rahmayetty. „Characterization and Application of Bayah Natural Zeolites for Ammonium Capture: Isotherm and Kinetic“. Materials Science Forum 988 (April 2020): 51–64. http://dx.doi.org/10.4028/www.scientific.net/msf.988.51.
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The aim of this study is to characterize Bayah natural zeolites and tested for ammonium capture. Characterization of Bayah natural zeolites were performed by X-ray diffraction (XRD), scanning electron microscope (SEM), and nitrogen physisorption. The natural zeolites were identified as mordenite and clinoptilolite. Non-zeolitic phase appeared on the XRD pattern was quartz. The morphology of clinoptilolite and mordenite were observed as platy and needle shape in the SEM images, respectively. Major cations were K+ and Ca2+ which were determined by energy dispersive X-ray. Nitrogen isotherm physisorption suggested that the natural zeolites was typical of type IV isotherm. Pore size distribution were determined using Barrett, Joyner, and Halenda model with mesopore size 3-5 nm. Ammonium exchange on Bayah natural zeolites were conducted in a batch experiment by varying the particle sizes, time and mass loading. Non-linear least squared method was applied to fit the experimental data with various kinetic and isotherm models. The kinetic data was well fitted with the Elovich equation with error 1.6 x 10-4. Isotherm adsorption of ammonium followed Langmuir-Vageler with error 4 x 10-2.
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Martinez-Ortigosa, Joaquin, Jorge Simancas, Jose A. Vidal-Moya, Fernando Rey, Susana Valencia und Teresa Blasco. „A Multi-Nuclear MAS-NMR Study on the Structural Properties of Silicalite-1 Zeolite Synthesized Using N- and P-Based Organic Structure Directing Agents“. Applied Sciences 11, Nr. 15 (26.07.2021): 6850. http://dx.doi.org/10.3390/app11156850.
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The nature of organic structure directing agents (OSDAs) is of paramount importance in the final properties of zeolites, particularly the framework and porosity. Recently, the use of P-containing OSDAs has been employed for new zeolites, but there is little discussion compared to their analogues N-OSDAs. The main objective of this work is the characterization of pure silica MFI zeolite (silicalite-1) prepared by the dual-template route with tetrapropylammonium (TPA), tetrapropylphosphonium (TPP) cations, and mixtures thereof aiming to understand by advanced NMR methods how the nature of the organic influences the physico-chemical properties of the zeolite. Silicalite-1 has been successfully synthesized using the dual-template procedure with TPA and TPP molecules. Both OSDAs are incorporated into the zeolite without any specific preference, differently to that observed before for the TEA/TEP system, and homogenously mixed inside of the zeolite voids. The presence of TPP leads to the incorporation of less F, raising the concentration of Q3-defective sites in the silicalite-1 zeolites. Detailed NMR results indicate that those structural defects are close to the –CH3 group of the entrapped OSDAs in the zeolite and these defects consist of at least two silanol groups stabilizing the Si-O- species, which is responsible for the charge balancing.
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Wu, Jianbing, Sen Wang, Haitao Li, Yin Zhang, Ruiping Shi und Yongxiang Zhao. „The Synergistic Effect of Acidic Properties and Channel Systems of Zeolites on the Synthesis of Polyoxymethylene Dimethyl Ethers from Dimethoxymethane and Trioxymethylene“. Nanomaterials 9, Nr. 9 (23.08.2019): 1192. http://dx.doi.org/10.3390/nano9091192.
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A series of zeolites with different topology structures, including SAPO-34, SUZ-4, ZSM-5, USY, MOR, and beta, were used to synthesize polyoxymethylene dimethyl ethers (PODEn) from dimethoxymethane (DMM) and trioxymethylene (TOM). The influence of acidic properties and channel systems were studied by activity evaluation, characterization, and theoretical calculation. The results confirmed that pore mouth diameter larger than a TOM molecule was an essential prerequisite for the synthesis of PODEn over zeolites, and the synergistic effect between medium-strong Brønsted acid sites (Brønsted MAS) and the maximal space of zeolites available determined the catalytic performance of all studied zeolites. DMM and TOM were firstly decomposed into methoxymethoxy groups (MMZ) and monomer CH2O over Brønsted MAS. Subsequently, the steric constraint of the maximum included sphere, with an appropriate size in zeolite channels, can promote the combination of CH2O and MMZ to form transition species ZO(CH2O)nCH3, which reacted with the methyl-end group to form PODEn over Brønsted MAS. Moreover, the reaction temperature showed different effects on the product selectivity and distribution, which also mainly depends on the size of the maximum space available in zeolite channels.
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Bakalár, Tomáš, Henrieta Pavolová, Kamil Kyšeľa und Zuzana Hajduová. „Characterization of Cu(II) and Zn(II) Sorption onto Zeolite“. Crystals 12, Nr. 7 (25.06.2022): 908. http://dx.doi.org/10.3390/cryst12070908.
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In this study, a batch sorption study approach was combined with an instrumental analytical approach of atomic absorption spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) for the sorption of copper and zinc ions from aqueous solution on zeolites. Both copper and zinc are biogenic elements; nevertheless, many industrial processes produce an excessive amount, which is why their efficient removal from water must be studied. Two types of zeolites, Zeolite Micro 20 (Z-M20) and Zeolite Micro 50 (Z-M50), were used. The results showed that the maximum sorption capacities for removal of Cu and Zn were 1.06 for CuSO4, 42.35 for Cu(NO3)2, 1.15 for ZnSO4 and 2.29 for Zn(NO3)2 adsorption onto Z-M20 and 0.45 for CuSO4, 1.67 for Cu(NO3)2, 0.39 for ZnSO4 and 1.51 for Zn(NO3)2 adsorption onto Z-M50. The maximum sorption capacities are higher for sulfates and the sorbent with smaller particle size. The sorption capacities of Cu and Zn for corresponding anion and particle size differ only up to 5–15%. Using XRD and XPS analyses before and after the sorption process, it was found that the content of both Cu and Zn in the surface layer and the bulk are the same for sorption onto sorbent with smaller particle size, but are higher in the surface layer than in the bulk for sorption onto sorbent with larger particle size. One of the main findings of this study is that a zeolite with smaller particles takes Cu and Zn by the whole particle, while with bigger particles, Cu and Zn concentrate in the surface of the particle. The results of the study may be used as an indicator for sorption efficiency of the studied zeolites for their application in the treatment of copper and zinc contaminated effluents.
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Pathak, Dhanju Mani, Pankaj Kumar Ghosh, Kishor Kr Shah und Anup Kumar Talukdar. „Synthesis and Characterization of Architecturally Modified Mesoporous-Microporous MFI (Mobil Five) Zeolite with Enhanced Catalytic Activity“. Asian Journal of Chemistry 33, Nr. 10 (2021): 2430–38. http://dx.doi.org/10.14233/ajchem.2021.23352.
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Four samples of MFI zeolites with silica to alumina ratio of 100 and using different silica to carbon mass ratios (1:1, 1:4, 1:8 and 1:12) were synthesized by using carbon black particles. Silica-alumina molar ratio imposes the framework structure to the synthesized zeolites. In general with an increase in the silica-alumina molar gel ratio, the thermal stability, acid resistance and hydrophobicity of the product increases and ion-exchange capacity decreases. A higher molar ratio (as high as 100) of silica to alumina is considered. ZSM-5 zeolites being mainly microporous, their use as catalyst is restricted only to small molecules. So, by introducing mesopores in zeolite framework, we basically tried to overcome the limited use of ZSM-5 in reactions involving large molecules. Pore structure of ZSM-5 can be modified by using carbon black particles during synthesis. Such type of synthesis can be used to introduce the mesopore and to decrease the crystal size of ZSM-5 zeolite. Different silica to carbon mass ratio is used to study the pore structure and crystal size of ZSM-5 zeolites under autogeneous pressure without adding any promoter or organic solvent. The synthesized samples were characterized by different techniques such as X-ray diffraction, FTIR spectroscopy, scanning electron microscopy, TGA and N2 adsorption-desorption isotherm. The samples exhibit high crystallinity (84-91%). The particle size ranged from 2.8 to 7.3 μm. Mesopore to micropore ratios was found to increase with increasing silicon to carbon mass ratio. These structurally modified meso-micro zeolite showed enhanced activity in the benzyl alcohol esterification reaction using acetic acid. The selectivity towards benzyl acetate in all the cases was found to be 100%.
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Ren, Tieqiang, Yue Sun, Yujia Wang, Lulu Wang, Qian Yu, Lisheng Liang, Xianming Kong und Haiyan Wang. „Regulation of TS-1 Zeolite with Small Particle Size by Colloidal Silicon Seed-Induced Synthesis and Application in Oxidative Desulfurization“. Materials 17, Nr. 23 (22.11.2024): 5722. http://dx.doi.org/10.3390/ma17235722.
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The dosages of colloidal silicon seeds in the seed-induced synthesis of TS-1 zeolites were investigated in detail. The characterization results revealed that the colloidal silicon seeds not only reduced the particle sizes but also promoted the incorporation of titanium atoms into the framework of TS-1 zeolites as prepared. SEM images and particle size distribution (PSD) confirmed that the particle sizes of TS-1 zeolite could be effectively reduced to about 150 nm. The lattice plane [2 1 0] and [0 2 0] of 7.0-Seed-TS-1 zeolite were well exposed, as observed by the HRTEM images. It is worth noting that the ratio of non-framework Ti atoms incorporated onto the surface of TS-1 zeolites increased slightly to 0.11% by XPS. By regulating the dosage of colloidal Si seeds and promoting rapid nucleation, the size of the crystals could be easily tuned, and then the resulting high external specific surface area and pore volume ensured the reactant accessibility to the active site. The TS-1 zeolites regulated by the 5.0~7.0% dosages of colloidal silicon seeds possessed high external specific surface areas (148.1 m2/g and 130.9 m2/g) and small particle sizes (about 150 nm). The oxidative desulfurization of 500 ppm DBT by 7.0-Seed-TS-1 zeolite could reach to 100%.
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NAKATA, Shin-ichi, Sachio ASAOKA und Hiromitsu TAKAHASHI. „Characterization of zeolites. V. Special articles on zeolite chemistry and technology. Characterization of zeolites by 23Na-MAS-NMR.“ NIPPON KAGAKU KAISHI, Nr. 3 (1989): 393–97. http://dx.doi.org/10.1246/nikkashi.1989.393.
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Vavouraki, Aikaterini, Georgios Bartzas und Konstantinos Komnitsas. „Synthesis of Zeolites from Greek Fly Ash and Assessment of Their Copper Removal Capacity“. Minerals 10, Nr. 10 (24.09.2020): 844. http://dx.doi.org/10.3390/min10100844.
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The objective of this study was to synthesize zeolites through fusion of lignite fly ash and NaOH or KOH pellets at 600 °C and assess their removal efficiency in terms of decontamination of solutions containing Cu(II) ions. The removal efficiency of the produced zeolites was tested in batch kinetic experiments using different zeolites and Cu(II) ion concentrations. Experimental data revealed that zeolites synthesized with the use of NaOH exhibited higher removal efficiency compared with those synthesized with the use of KOH. Kinetic data showed that the pseudo-second-order equations described well the removal process. Copper removal was mainly accomplished through the concerted action of chemisorption and intraparticle diffusion. Analytical techniques involving XRF, XRD, FTIR, SEM/EDS and XPS were used for the characterization and morphology analysis of the produced zeolites. SEM/EDS confirmed the presence of copper on the zeolite surface. XPS spectra of Cu2p at 934.3 eV proved the presence of Cu(II) oxidation state, confirming the possible formation of CuO and/or Cu-Cl.
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Peng, Gong Ming, De Lian Yi, Lin Wu, Zhao Hui Ou Yang und Jian Guo Wang. „Novel Base Catalysts by Nitridation of Zeolite Y: Characterization and Catalytic Evaluation“. Advanced Materials Research 148-149 (Oktober 2010): 1096–99. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.1096.
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Novel base catalysts were obtained by subjecting Y zeolites to nitridation. These materials were characterized by elemental analysis, X-ray diffraction, BET surface area analysis, In situ diffuse reflectance infrared fourier transform Spectroscopy (in situ DRIFTS), Pyrrole adsorption. The results indicated nitrogen-incorporated NaY zeolite was well ordered and possess high surface area and pore volume. In situ DRIFTS experiments confirmed that N atoms had been introduced into the framework by nitridation to form -NH2- or -NH- species. It was found that Lewis basicity of these oxynitride materials increased by the pyrrole adsorption. Furthmore, the basic catalytic properties of nitrogen-incorporated zeolites were evaluated by Knoevenagal condensation of benzaldehyde with diethyl malonate and enhanced yield of product was achieved.
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M. Ibrahim, Jamal Eldin F., Emese Kurovics, Mohammed Tihtih, László A. Gömze und István Kocserha. „Synthesis and characterization of alkali-activated zeolite-poor rocks“. Journal of Physics: Conference Series 2315, Nr. 1 (01.07.2022): 012020. http://dx.doi.org/10.1088/1742-6596/2315/1/012020.
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Abstract Zeolite-geopolymer composite materials were obtained through mechanical activation using planetary ball mill followed by chemical activation using an aqueous solution of sodium hydroxide (NaOH), these materials integrate the beneficial features of both zeolites and geopolymers. In this present work, the morphological characteristics, microstructure, phase determination of raw materials and the generated ceramic samples were studied by several characterization methods such as SEM, EDS and XRD. The microstructural analysis confirms the formation of needle-like structure in sub-micron and nanostructure, while the phase identification reveals the creation of single-phase zeolite (heulandite).
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Stojkić, Ognjen, Radislav Filipović, Mladen Janković, Duško Kostić, Mitar Perusic, Srećko Stopić und Vladimir Damjanović. „Influence of process parameters on the adsorption properties of zeolite 13X“. Journal of Chemists, Technologists and Environmentalists 5, Nr. 1 (30.12.2024): 20–31. https://doi.org/10.59919/jcte05202401005.
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<p>Zeolite 13X is one of the best adsorbents among zeolites and one of the most commercially available zeolites.&nbsp; This paper investigates the influence of several process parameters on the properties of 13X zeolite, including crystallization temperature, crystallization duration and Si/Al molar ratio in the starting reaction mixture. The quality of the obtained powders was examined in detail through a series of analytical and instrumental methods, presented in the paper. Water and CO<sub>2</sub> adsorption capacities were determined as key quality parameters of 13X zeolite, and additional characterization was performed by determining material granulometry, specific surface area (BET analysis), crystallinity (X-ray diffraction method) as well and SEM analysis. The obtained results indicate a clear dependence between the examined process parameters of the system and the characteristics of the synthesized materials, thus enabling the selection of optimal conditions for the synthesis of 13X zeolite.</p>
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Dimitrijevic, Radovan, und Vera Dondur. „Thermally induced conversion of Mg2+ cation exchanged LTA, FAU, GIS and SOD zeolites: Syntheses and characterization of γ-cordierite, a new Mg2Al4Si5O18 polymorph“. Journal of the Serbian Chemical Society 72, Nr. 12 (2007): 1351–62. http://dx.doi.org/10.2298/jsc0712351d.
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The thermal behaviours of fully Mg2+ cation exchanged LTA, FAU (X and Y species), GIS and SOD zeolites were investigated in the temperature range from ambient to 1400 ?C. The initial zeolite frameworks collapsed into amorphous intermediate substances after air heating between 800-850 ?C. Prolonged annealing of these products above 850 ?C induced recrystallization into sapphirine-like phases (Mg-LTA and Mg-FAUx zeolites) and ?-cordierite (Mg-FAUy and Mg-GIS zeolites) phases. These phases were unstable during further temperature/time treatment and between 1000-1100 ?C they polymorphously transformed into ?-cordierite, a new Mg2Al4Si5O18 polymorph. ?-Cordierite was formed as a transformation product from the investigated zeolite precursors, except for the Mg-SOD zeolite. Structurally the ?-cordierite phase is a modulated, Mg-stuffed derivative of cristobalite with the approximate composition Mg2Al4Si5O18, which precedes the appearance of ?-cordierite. The orthorhombic unit cell dimensions calculated from X-ray powder diffraction pattern are: a = 16.387(7) ?, b = 8.835(4) ?, c = 7.853(3) ?. ?-Cordierite has a narrow range of temperature stability (1100-1200 ?C) and during prolonged temperature/time treatment, it is polymorphously transformed to the ?-cordierite phase.
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Kalista, Nadia Nanda, Rahmana Emran Kartasasmita, Marlia Singgih Wibowo und Lenny Marilyn Estiaty. „KARAKTERISASI DAN PEMURNIAN ZEOLIT ALAM LAMPUNG SEBAGAI KANDIDAT ANTIDOTUM KERACUNAN TIMBAL“. Acta Pharmaceutica Indonesia 42, Nr. 2 (27.12.2017): 84–91. http://dx.doi.org/10.5614/api.v42i2.5656.
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Indonesia memiliki kelimpahan zeolit yang berpotensi dapat dikembangkan sebagai zeolit yang berderajat farmasi. Penelitian ini bertujuan untuk mendapatkan zeolit olahan dengan karakteristik yang cocok sebagai bahan baku farmasi. Zeolit alam diproses dengan cara pencucian menggunakan masing-masing larutan HCl, aquabidest, dan EDTA lalu diikuti dengan pemanasan pada 350 °C. Sebelum dan sesudah pengolahan sampel zeolit dikarakterisasi menggunakan berbagai metode instrumental. Selanjutnya, zeolit olahan diuji kemampuannya untuk menjerap parasetamol dan timbal. Hasil analisis menunjukkan bahwa komposisi sampel zeolit > 91% berjenis klinoptilolit dengan kandungan utama unsur Si, Al dan K. Setelah pencucian dengan larutan HCl 1 M, EDTA 0,1 M dan aquabidest, kadar As dalam masing-masing sampel zeolit 4,12 ± 0,75 ppm, < 0,1 ppm dan 11,8 ± 0,56 ppm dan kadar Pb untuk seluruh sampel < 1 ppm, sedangkan Cd dari semua sampel < 1 ppm. Tidak ada perubahan struktur dalam sampel zeolit yang teramati setelah proses pencucian dan pemanasan. Zeolit yang dicuci dengan larutan EDTA mampu menjerap Pb dalam cairan lambung buatan tanpa pepsin secara efektif dengan penurunan kadar hingga 89% namun tidak mampu menjerap parasetamol secara efektif. Disimpulkan bahwa hasil proses zeolit menunjukkan karakteristik yang cocok sebagai kandidat bahan baku farmasi. Zeolit yang diberi perlakuan dengan EDTA mampu menjerap Pb secara efektif sehingga berpeluang digunakan sebagai antidot lokal dalam kasus keracunan Pb akut.Kata kunci: zeolit, klinoptilolit, logam berat. CHARACTERIZATION AND PURIFICATION OF NATURAL LAMPUNG ZEOLITE AS A CANDIDATE OF ANTIDOTE OF LEAD INTOXICATIONABSTRACTIndonesia has the abundance potential of zeolites having possibility to be developed as pharmaceutical grade zeolites. This research aimed to obtain processed zeolite showing suitable characteristics as pharmaceutical ingredient. Natural zeolite was processed by means of washing using dilute HCl, aquabidest and EDTA solutions, respectively and subsequently followed by heating at 350 oC. Prior and after processing, the zeolite samples were characterized using various instrumental methods. Furthermore, the processed zeolite was tested for its ability to adsorb paracetamol and lead. The analysis results confirmed that the composition of zeolite samples were > 91% of clinoptilolite mainly composed of Si, Al and K. After washing with 1 M HCl, 0.1 M EDTA and aquabidest, the level of As in each of zeolite samples were 4.12 ± 0.75 ppm, < 0.1 ppm and 11.8 ± 0.56 ppm and those of Pb were all < 1 ppm, while those of Cd from all samples were < 1 ppm, respectively. No structural changes in zeolite samples were observed after washing and heating treatment. EDTA treated zeolite was able to adsorb Pb in artificial gastric fluid without pepsin effectively up to 89% reduction but failed to adsorb paracetamol effectively. It was concluded that processed natural zeolite was suitable as a pharmaceutical ingredient. EDTA-treated zeolite was able to adsorb Pb effectively and hence could be possibly applied as local antidote in the case of acute Pb intoxication.Keywords: zeolite, clinoptilolite, heavy metals.
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Irawan, Anton, Yazid Bindar, Teguh Kurniawan, Hafid Alwan, Rosid Rosid und Nisa Aina Fauziah. „Bayah Natural Zeolites to Upgrade the Quality of Bio Crude Oil from Empty Fruit Bunch Pyrolysis“. Journal of Engineering and Technological Sciences 53, Nr. 3 (28.06.2021): 210308. http://dx.doi.org/10.5614/j.eng.technol.sci.2021.53.3.8.
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Currently, the fuel oil for transportation and industry is produced mostly from fossil fuels. Because fossil fuels are a limited resource, biomass could be an alternative resource. Empty fruit bunch (EFB) is biomass waste from fresh fruit bunch processing in palm oil mills. EFB can be converted to bio-crude oil through pyrolysis at temperatures from 400 to 600 °C. The quality of bio-crude oil must be upgraded due to its high oxygen content. Esterification of bio-crude oil potentially improves the quality of bio-crude oil by using zeolite as catalyst. The purpose of this research was to investigate the properties of Bayah natural zeolites for upgrading the quality of bio-crude oil from EFB pyrolysis. Bayah natural zeolite was activated using various NaOH concentrations. Characterization of the natural zeolites was performed by using X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray (SEM-EDX), and nitrogen physisorption. The optimum ratio of Si/Al of the modified Bayah natural zeolites was 3.91. The surface area of the parent was initially 19 m2/g and increased significantly to 150 m2/g after treatment with 0.4 M NaOH solution. The application of the activated zeolites for bio-crude oil esterification successfully decreased the total acid number.
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Larsen, Sarah C. „Nanocrystalline Zeolites and Zeolite Structures: Synthesis, Characterization, and Applications“. Journal of Physical Chemistry C 111, Nr. 50 (07.11.2007): 18464–74. http://dx.doi.org/10.1021/jp074980m.
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Barros, Thiago Rodrigo Barbosa, Thianne Silva Batista Barbosa und Meiry Gláucia Freire Rodrigues. „Adsorption of reactive yellow BF-3R dye by CTABr modified zeolite NaY“. Research, Society and Development 10, Nr. 14 (03.11.2021): e323101422147. http://dx.doi.org/10.33448/rsd-v10i14.22147.
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Textile industries generate effluents composed of organic salts and complexes from dyes not fixed on fabrics, or not degraded by the inefficiency of conventional treatment processes, which represents a high potential for environmental impact due to inadequate disposal of the generated effluent. Zeolites are porous materials that have a three-dimensional structure containing tetrahedrals of AlO4 e SiO4 which can be modified to improve its properties. The adsorption process using zeolites as adsorbents can be considered an excellent economic physical treatment to solve or minimize such a problem. This work presents an experimental study focusing on the preparation and characterization of zeolite NaY and modified with organic surfactant cetyltrimethylammonium bromide (CTABr) intended to be used as adsorbent in the process of removing yellow dye BF-3R in dye-water system batch system. The samples were characterized by X-ray diffraction (XRD), Infrared spectroscopy (IR) and thermogravimetry (TG). The effect of process parameter such as pH was studied. Results revealed that even though the modified cetyltrimethylammonium bromide organic surfactant (CTABr) did not cause alterations on the zeolite NaY structure. The IR results revealed that CTABr was successfully incorporated to zeolite NaY structure. The best conditions were established with respect to pH to saturate the available sites located on the zeolite NaY and NaY_CTABr surface. The maximum adsorption capacities were 3.35 and mg/g for dye 5.35 using as-synthesized zeolite NaY and CTABr modified zeolite NaY. Modified zeolites are excellent adsorbents for removing reactive dyes from industrial wastewater.