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Sugiarti, Sri, Charlena Charlena i Nurul Afiati Aflakhah. "Zeolit Sintetis Terfungsionalisasi 3-(Trimetoksisilil)-1-Propantiol sebagai Adsorben Kation Cu(II) dan Biru Metilena". Jurnal Kimia VALENSI 3, nr 1 (31.05.2017): 11–19. http://dx.doi.org/10.15408/jkv.v3i1.5144.
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The more commonly used method for making synthetic zeolite from kaolin is hydrothermal method. This research tested a sol-gel method in processing synthetic zeolit using kaolin as the basic ingrediant. The synthetic zeolite derived from the sol-gel method was then characterized using X-ray Difractometer and Scanning Electron Microscope, which found resulting products zeolite-A, zeolite Y and sodalite. The adsorption ability of the synthetic zeolites was tested using Cu(II) and methylene blue. Functionalization of the synthetic zeolites by 3-(trimetoksisilil)-1-propantiol was done to increase adsorption capacity. Zeolite A modified by 3-(trimetoksisilil)-1-propantiol had the greater capacity to adsorb methylene blue at 30.11 mg/g. The adsorption isotherms of all the synthetic zeolites approached the Langmuir form. The adsorption energy off all synthetic zeolites approached the chemical adsorption.DOI: http://dx.doi.org/10.15408/jkv.v0i0.5144
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Solihat, Imas, Lilis Sulistiawaty, Putri Hawa Syaifie i 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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Flores Díaz, Alicia Amairani, Martha Alicia Velázquez Machuca, Adriana Medina Ramírez, José Luis Montañez Soto, José Venegas González i José Luis Pimentel Equihua. "Boron adsorption on modified zeolites: Effect of modifier and source of water". Revista Internacional de Contaminación Ambiental 39 (2.06.2023): 139–57. http://dx.doi.org/10.20937/rica.54473.
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The removal of boron from drinking water is a concern in various parts of the world due to the toxic effects of this metalloid in high concentrations. In this paper, zeolites LTL and FAU X were synthesized and modified with salts of nickel (NiCl2), iron (FeCl3), and aminopropyltriethoxysilane (APS) in order to promote their affinity for boron species present in aqueous systems. The adsorption capacity of modified zeolites for boron was evaluated in a synthetic boron solution and with groundwater samples for human use. The effect of the pH and zeolite dose was studied in adsorption tests using groundwater. The modified zeolites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen physisorption, and Fourier-transform infrared spectroscopy. Results indicated that the modification of zeolites favors affinity for boron species. The highest adsorption capacity of boron on zeolites was achieved in the synthetic solution. The adsorption capacity of the modified zeolites depended on the pH, the electrical conductivity, the modifying agent, the zeolitic structure, and the dose of adsorbent. The zeolitic structure-modifying agent interaction was decisive for boron adsorption capacity, with LTL-Ni zeolite being the best-performing adsorbent, thanks to its textural properties and nickel’s ability to form complexes with boron species.
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Patrylak, Lyubov, Serhii Konovalov, Stepan Zubenko i Anzhela Yakovenko. "Transformation of Hexoses on Natural and Synthetic Zeolites". Chemistry & Chemical Technology 17, nr 2 (1.06.2023): 287–93. http://dx.doi.org/10.23939/chcht17.02.287.
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A number of zeolite catalysts based on synthetic powder zeolites and natural Ukrainian clinoptilolite as well as mordenite-clinoptilolite zeolite rocks were synthesized. The activity and selectivity of the prepared samples were compared in glucose and fructose dehydration into 5-hydroxymethylfurfural in a dimethyl sulfoxide environment.
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Azizi, Seyed Naser, Akram Alavi Daghigh i Maryam Abrishamkar. "Phase Transformation of Zeolite P to Y and Analcime Zeolites due to Changing the Time and Temperature". Journal of Spectroscopy 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/428216.
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In the present study, the synthesis of template free zeolite P under hydrothermal condition was investigated. The effects of parameters such as Si/Al ratios (3–45), crystallization temperatures (80–160°C), and cry (40–60 h) on the synthesis of zeolite P were studied. The phase transformation of zeolite P to two types of high crystallinity Y and analcime zeolites due to change of temperature was observed. The effect of temperature on the achievement of two different zeolite types (Y and analcime) with a constant initial synthetic composition under organic free synthesis of zeolite P was studied. The zeolitic products were characterized by X-ray diffraction, scanning electron microscopy, and IR spectroscopy techniques.
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Woszuk, Agnieszka. "Application of Fly Ash Derived Zeolites in Warm-Mix Asphalt Technology". Materials 11, nr 9 (27.08.2018): 1542. http://dx.doi.org/10.3390/ma11091542.
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In recent years, numerous studies have been carried out on new technologies allowing to reduce of mix asphalt production temperatures. One of the possibilities is to foam the asphalt with “water-containing” additives, which include zeolites. So far, mainly synthetic zeolites of the Linde A structure type, obtained from chemical reagents, and natural clinoptilolite have been used in WMA technology. In this studies, the synthetic zeolites produced from fly ashes with 4 different types of crystalline structure were analyzed. Zeolite materials were characterized by textural parameters and thermal analysis. The amount of zeolite added to asphalt was 0, 3, 5, 7 wt % in relation to the weight of asphalt. Determination of dynamic viscosity was performed at two temperatures: 135 and 160 and 4 time intervals. The tests were performed for two asphalt binders: 35/50 and 100/150 penetration grade. As a conclusion, it was found that the viscosity of asphalt pastes with zeolitic materials increases with the increase in the amount of zeolite added. The increase level depends mainly on the textural parameters. The potential usefulness of fly ash derived zeolites in the process of asphalt foaming, which depends mainly on the amount of water contained in the zeolite structure and the method of its release, has been proved.
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PANDOVA, IVETA, i MIROSLAV RIMAR. "REDUCTION OF METAL CATIONS CONTENT FROM THE AQUEOUS SOLUTIONS BY SORBENTS". MM Science Journal 2021, nr 6 (15.12.2021): 5307–11. http://dx.doi.org/10.17973/mmsj.2021_12_2021044.
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The article presents the results of research on reducing the concentration of heavy metals, such as copper and nickel, on natural zeolite in comparison with synthetic zeolite and chemically treated natural zeolite. The reduction of the content of specific types of heavy metals from aqueous solutions was investigated by the method of sorption kinetics. The results indicate the ability of natural zeolites to compete with synthetic zeolites.
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Ovchinnikov, Grygoriy A., Valentina А. Gorskikh, Ilyana I. Fassalovа, Vadim S. Тukhvatshin i Rifkat F. Talipov. "KINETICS OF ADSORPTION OF 4,4-DIMETHYL-1,3-DIOXANE FROM AQUEOUS SOLUTIONS BY SYNTHETIC ZEOLITES IN PRESENCE OF PHOSPHORIC ACID". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, nr 12 (12.12.2018): 81–86. http://dx.doi.org/10.6060/ivkkt.20186112.5542.
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In this paper we studied the kinetics of adsorption of 4,4-dimethyl-1,3-dioxane by synthetic zeolites from aqueous solutions in the presence of phosphoric acid. Kinetic mechanism of DMD adsorption from aqueous solutions by synthetic zeolites were considered from the position of three kinetic models: the diffusion model (Boyd and Morris-Weber model), Lagergeren (pseudo-first order), and pseudo-second order. As sorbents we have used synthetic zeolites KA, NaA, CaA, CaX, NaX with a pore diameter of 3-9 Å. DMD (boiling point is 113-114 ºC) was synthesized from isobutylene. Chromatographic analysis was performed on Chromatec Crystal 5000.1 instrument (Russia) using columns (2.0 m in length) with silicone SE-30 (5%) stationary phase (0.16–0.20 mm, operating temperature is 50–220 °C) with nitrogen as a carrier gas. An adsorption of DMD from aqueous solutions was investigated at (75±1) °C from a limited volume under constant mixing (laboratory mechanical stirrer, 17 rps). The contact time of the solution with samples of sorbents varied from 120 to 3600 s. The DMD concentration in solution was determined by the chromatographic method (the internal standard is 4,4,5-trimethyl-1,3-dioxane). The values of the external and internal mass transfer diffusion coefficients were obtained. The effect of the size of zeolite’s pores on the contribution of the external or internal diffusion mass transfer in the process of adsorption of 4,4-dimethyl-1,3-dioxane was founded. The time of establishment of sorption equilibrium was determined. We have found that the process of adsorption of DMD by synthetic zeolites in the presence of phosphoric acid is determined by the values of the diameter of the pores. It is shown that the value of pore diameter of synthetic zeolites does not influence on the аdsorption equilibrium time of DMD. The adsorption equilibrium time for all used family zeolites is 900 s. The kinetics of adsorption of DMD on synthetic zeolites can be correctly described by a pseudo-second-order equation, which indicates the presence of sorbate (DMD) interaction with the sorbent (synthetic zeolite).
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Septiansyah, Sy Indra, i Maya Santi. "Pemanfaatan Alumina Waste dari Tailing Bauksit Menjadi Zeolit Adsorben". EKSPLORIUM 39, nr 2 (31.01.2019): 123. http://dx.doi.org/10.17146/eksplorium.2018.39.2.4982.
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ABSTRAK Alumina waste dari tailing bauksit merupakan produk samping yang berasal dari hasil benefisiasi bijih bauksit. Proses benefisiasi dilakukan dengan cara memisahkan partikel-partikel yang ada seperti lumpur atau clay, akar-akar, butiran bijih bauksit berkisar 2 mm yang dibuang atau menjadi waste product atau disebut sebagai limbah tailing. Tingginya kadar alumina dan silika dalam tailing bauksit menjadi salah satu alasan mengapa tailingini dapat dimanfaatkan sebagai bahan dasar dalam pembuatan produk baru yaitu zeolit sintetis. Zeolit sintetis dipilih karena zeolit merupakan produk impor, harganya mahal dan memiliki sifat yang seragam serta >150 jenis zeolit sintetis dapat dibuat secara komersial dan bahkan di industri zeolit dapat dimanfaatkan secara luas sebagai adsorben, penukar ion, membrane, katalis, dan lain-lain.Hasil analisis kimia tailing bauksit menunjukkan komposisi: alumina (Al2O3) sekitar 49,41%, silika (SiO2) sekitar 12,58%, hematit (Fe2O3) sekitar 10,6% dan beberapa oksida anorganik lainnya dalam jumlah yang kecil. Proses konversi tailing bauksit menjadi zeolit adsorben dilakukan dengan metode fusi kaustik untuk mendapatkan ekstrak fusi (mother liquor) kemudian dilanjutkan dengan penambahan prekursor natrium silikat dengan formula sintesis Si/Al(1:1). Kristalisasi produk dilakukan dengan menggunakan metode hidrotermal pada suhu rendah dengan variable waktu inkubasi yang ditentukan. Reaksi sodium aluminat dan sodium silikat telah mentransformasi fasa amorf gel menjadi fasa kristalin zeolit yang berbentuk serbuk putih halus.ABSTRACTA lumina waste from bauxite tailings is the by products derived from bauxite ore beneficiation. The beneficiation process is done by separating the particles that exist such as mud or clay, roots, grain, bauxite ore ranges from 2 mm are discarded or be referred to as a waste product or tailings. High concentration of alumina and silica in bauxite tailings considered as one of the reasons why these tailings can be used as base material in the making new products, namely synthetic zeolites. Zeolites synthetic is selected because zeolites are imported, expensive and have uniform properties and >150 types of synthetic zeolites can be made commercially and even in industrial zeolite can be used widely as an adsorbent, ion exchange, membranes, catalysts, etc. The chemical analysis of bauxite tailings showed the composition of alumina (Al2O3) is approximately 49.41% silica (SiO2) is about 12.58%, hematite (Fe2O3) is approximately 10.6% and some other inorganic oxides are small amounts. The conversion process bauxite tailings into zeolite is carried out by caustic fusion method to extract the fusion (alumina precursor) followed by the addition of sodium silicate precursor with synthesis formula 1.2Na2O.0.5SiO2.0.5Al2O3.10H2O and crystallization products is carried out by the hydrothermal method at low temperatures with variable incubation period specified. The results showed that the zeolite synthesis of bauxite tailings using caustic fusion and followed by crystallization at low temperature and under atmospheric pressure has succeeded in transforming the product into an amorphous phase to the crystalline phase product zeolite adsorbent.
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Łach, Michał, Agnieszka Grela, Tomasz Bajda, Dariusz Mierzwiński, Norbert Komar i Janusz Mikuła. "Production of Zeolite Sorbents from Burning and Co-burning Biomass with Coal". E3S Web of Conferences 44 (2018): 00097. http://dx.doi.org/10.1051/e3sconf/20184400097.
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The limited resources of natural zeolites make it necessary to search for and use synthetic products. This paper presents a method of producing zeolite sorbents resulting from hydrothermal synthesis in an autoclave. The raw materials used in the syntheses were fluidized-bed fly ashes derived from the burning of forest biomass and sunflower hulls and two fly ashes derived from biomass combustion. The raw materials and zeolite sorbents were characterised using the analysis methods of phase composition and textural properties of the samples. The sorptive capacity of the raw materials and zeolite sorbents was determined by means of cation and anion exchange capacity. The analyses and research have shown that as a result of the synthesis process it is possible to obtain the following zeolite phases: sodalite, faujasite, chabazite. The determined value of the cation and anion exchange capacity for synthetic zeolite sorbents are greater than those which characterise natural zeolites.
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Tang, Hui, Xiaoyi Xu, Bin Wang, Chenpei Lv i Dezhi Shi. "Removal of Ammonium from Swine Wastewater Using Synthesized Zeolite from Fly Ash". Sustainability 12, nr 8 (22.04.2020): 3423. http://dx.doi.org/10.3390/su12083423.
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Synthetic zeolites with pretreated fly ash as a raw material were used to remove ammonium from wastewater using a hydrothermal method in this study. Two pretreatment methods of fly ash were used to compare the ammonium removal of zeolites: water-washing and pickling. In addition, the effects of several factors including the time, temperature, pH, adsorbent dosage, coexisting ions and initial concentration were investigated to gain insight into the adsorption rate, behavior and mechanism of synthetic zeolites for ammonium. N2 adsorption/desorption isotherms showed that the synthetic zeolite was a mesoporous material with a higher specific area (13.05 m2/g) than the values for raw fly ash (0.34 m2/g). The X-ray diffraction result suggested that the synthetic products mainly belonged to zeolite P and Y. The adsorption kinetic data fitted well with a pseudo-second-order model. The maximum ammonium adsorption capacity was 32.16 mg/g. The synthetic zeolites were also applied to adsorb the ammonium from real swine wastewater. The ammonium removal efficiencies in raw swine wastewater and effluent from the biochemical unit were 64.34% and 79.61%, respectively, which indicated that the synthetic zeolites have a good application for real ammonium wastewater.
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Thomas, John A., i Bryan Ballantyne. "Toxicological Assessment of Zeolites". Journal of the American College of Toxicology 11, nr 3 (maj 1992): 259–73. http://dx.doi.org/10.3109/10915819209141860.
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The zeolites, sometimes referred to as molecular sieves, are a large group of natural and synthetic materials. Their composition may consist of an aluminosilicate framework containing alkali or alkaline earth cations. Zeolites exhibit fibrous, cuboidal, or other crystalline morphologies. Often considered nuisance dusts, these materials may evoke pulmonary changes leading to irritation of the respiratory tract. Pulmonary inflammatory responses, particularly those caused by natural occurring zeolites, can lead to fibrosis and even mesotheliomas. Synthetic zeolite structures, usually cuboidal, produce irritation of the eyes and mucous membranes, but there is no evidence of significant pathologic changes in the lungs. Few nonpulmonary toxicologic changes are produced by either the natural or synthetic zeolites.
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Hao, Xiang Ying, Cui Zhang, Shuang Xi Liu i Hai Fu Guo. "A Novel Approach to Disperse CuO onto the Zeolites Mordenite and Beta". Advanced Materials Research 284-286 (lipiec 2011): 58–64. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.58.
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Zeolites mordenite (MOR) and β decorated with high dispersion degree and loading content of CuO composite (symbolized as CuO/zeolite) were prepared via a novel method-the stepped hydrothermal synthesis. The resultant composite were characterized with details by powder XRD, ICP-AES, H2-TPR and TEM techniques. Shown by experiment, the stepped hydrothermal synthetic method adopted in the present research using urea as alkali source as well as benefiting from the ultrasonic wash treatment hardly damages the zeolitic framework structure. Compared with ammonia, high dispersion degree and loading level of CuO are yielded as a consequence of the employment of urea as alkali source. Besides, the ultrasonic wash treatment not only removes some CuO precursors that deposit on the external surface of the porous support but also produces a uniform distribution of CuO particles with smaller dimension on the surface of zeolites: CuO are dispersed in nanoscale of about 4-8 nm on mordenite and 2-5 nm on zeolite β. The present synthetic strategy could be therefore applied as a novel general method for the manufacture of functional materials in a wide spectrum.
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Jang, Eunhee, Jeong Hyeon Lee, Sungwon Hong, Yanghwan Jeong, Jin Chul Kim, Dongjae Kim, Hionsuck Baik i in. "An unprecedented c-oriented DDR@MWW zeolite hybrid membrane: new insights into H2-permselectivities via six membered-ring pores". Journal of Materials Chemistry A 8, nr 28 (2020): 14071–81. http://dx.doi.org/10.1039/d0ta03892j.
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Liguori, Barbara, Paolo Aprea, Bruno de Gennaro, Fabio Iucolano, Abner Colella i Domenico Caputo. "Pozzolanic Activity of Zeolites: The Role of Si/Al Ratio". Materials 12, nr 24 (17.12.2019): 4231. http://dx.doi.org/10.3390/ma12244231.
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A great challenge of research is the utilization of natural or synthetic zeolites, in place of natural pozzolans, for manufacturing blended cements. The difficulties of interpretation of the pozzolanic behavior of natural zeolite-rich materials and the role played by their nature and composition can be overcome by studying more simple systems, such as pure synthetic zeolites. This study aims at investigating the pozzolanic ability of isostructural zeolites with different framework compositions, such as three sodium zeolites of the faujasite (FAU) framework type: LSX, X, and Y. The pozzolanic activity has been estimated by thermogravimetry and X-ray diffraction analysis. The overall outcome of the investigation is that the zeolite structure affects its pozzolanic activity, as zeolites with similar framework densities exhibit distinct abilities to fix lime. Moreover, the framework composition is effective either from a kinetic point of view or on the total amount of fixed lime. Zeolite X appears to possess the best average features.
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Kozera-Sucharda, Bożena, Barbara Gworek i Igor Kondzielski. "The Simultaneous Removal of Zinc and Cadmium from Multicomponent Aqueous Solutions by Their Sorption onto Selected Natural and Synthetic Zeolites". Minerals 10, nr 4 (11.04.2020): 343. http://dx.doi.org/10.3390/min10040343.
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Natural and synthetic aluminosilicate minerals, in particular zeolites, are considered to be very useful in remediation processes, such as purification of waters polluted with heavy metals. That is due to their unique and outstanding physico-chemical properties, rendering them highly efficient, low-cost, and environmentally friendly sorbents of various environmental pollutants. The aim of this study was to examine the sorption capacity of four selected zeolites: A natural zeolite and three synthetic zeolites (3A, 10A, and 13X), towards zinc and cadmium present in multicomponent aqueous solutions, in relation to identified sorption mechanisms. It was stated that synthetic zeolites 3A and 10A were the most efficient in simultaneous removal of zinc and cadmium from aqueous solutions. Additionally, zeolite 10A was demonstrated to be the mineral best coping with prolonged pollution of water with those elements. The mechanism of sorption identified for tested minerals was physisorption.
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Murrieta-Rico, Fabian N., Joel Antúnez-García, Rosario I. Yocupicio-Gaxiola, Armando Reyes Serrato, Vitalii Petranovskii, Mufei Xiao, Oleg Sergiyenko, Wendy Flores-Fuentes i Julio C. Rodríguez-Quiñonez. "Frequency Response Analysis of FAU, LTA and MFI Zeolites Using UV-Vis and Electrochemical Impedance Spectroscopy". Optics 4, nr 3 (28.07.2023): 459–72. http://dx.doi.org/10.3390/opt4030033.
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Zeolites are porous materials that have cavities interconnected by channels. These crystalline materials are composed of Si-O tetrahedral structures, and according to the assembly of such tetrahedral structures, specific crystalline structures are obtained. Until now, it has been said that there are more than 245 different zeolitic frameworks, and since each one has a specific distribution of pores and cavities, each kind of zeolite has a specific area-to-volume ratio. As a result of the type of zeolite structure, the zeolite can exhibit specific properties, i.e., electrical or optical. Moreover, the physical properties of zeolites can be modified after the inclusion of another chemical species in their structure or in their voids, which can result in tuning a zeolite for specific applications. In this work, synthetic zeolites of types LTA, FAU and MFI are characterized by a number of methods. In particular, the data from UV-Vis spectroscopy are analyzed, and the effect of crystalline structure on properties such as optical bandgap, refractive index, absorption coefficient, incident photon frequency, and extinction coefficient is studied.
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Girskas, Giedrius, Ina Pundienė i Jolanta Pranckevičienė. "The Effect of Natural and Synthesised Zeolites on Cement-Based Materials Hydration and Hardened State Properties". Materials 16, nr 16 (13.08.2023): 5608. http://dx.doi.org/10.3390/ma16165608.
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The synthesis of zeolites from difficult-to-utilise waste materials facilitates the creation of more financially attractive and efficient synthetic zeolites. These can be incorporated into construction materials, resulting in a reduction in cement usage and the production of superior, clean, and sustainable construction materials. The potential to enhance the hydration rate of fresh cement paste by substituting up to 10% of the cement with two synthetic zeolites—one commercially produced and the other synthesised from waste and natural zeolite—was explored. Due to a higher Al/Na ratio, newly sintered waste-based zeolite possesses six times higher electrical conductivity compared to industrially produced 4A zeolite and more than 20 times higher electrical conductivity compared to natural zeolite. As the sequence of this fact, substituting up to 10% of the cement with AX zeolite cement paste accelerates the maximum heat release rate time and increases the total heat by 8.5% after 48 h of hydration. The structure, compressive strength, and water absorption of the hardened cement paste depends on the Al/Na ratio, pH, and electrical conductivity values of the zeolite used. The findings revealed that AX zeolite, due to presence of mineral gibbsite, which speeds up hydration products, such as CSH development, increases the compressive strength up to 28.6% after 28 days of curing and reduces the water absorption by up to 1.5%. Newly synthesised waste-based AX zeolite is cheap because its production is based on waste materials and is mostly promising due to superior properties of created construction materials compared to the other presented zeolites.
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Woszuk, Agnieszka, Lidia Bandura i Rafał Panek. "Application of zeolites as fillers in mix asphalt". Budownictwo i Architektura 14, nr 1 (10.03.2015): 127–34. http://dx.doi.org/10.35784/bud-arch.1677.
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The aim of this paper is estimation of the effect of zeolites addition on properties of asphalt and examination of possible application of zeolites in mix asphalt as a filler. The addition of zeolites to the mix asphalt is one of the ways used for reduction of technological temperatures by asphalt foaming. At the same time the zeolite material replaces the filler. The paper presents the results of studies on the synthetic zeolite NaP1, natural zeolite- clinoptilolite and mineral filled.
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Yang, Li Ying, i Yi Qiu Tan. "Compacting Properties of Zeolite Based Warm Asphalt Mixture". Advanced Engineering Forum 5 (lipiec 2012): 299–304. http://dx.doi.org/10.4028/www.scientific.net/aef.5.299.
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Warm asphalt mixture develops rapidly throughout the world in recent years. Zeolite based warm mix is one of the warm mixtures. In this paper, seven kinds of zeolites including six natural zeolites and one synthetic zeolite are selected. As warm mix additives, their physical properties such as density, water content and pore arrangements are tested respectively. To evaluate the compacting properties of zeolites based warm asphalt mixture, AC-20 mixture is designed and compaction is conducted. It shows that zeolites can reduce the compacting temperature for both Marshall and gyratory compaction. Temperature is the main factors which influence the compaction effect. Type of zeolite affects compaction to some extent. Marshall compaction is more sensitive to zeolite than gyratory compaction.
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Miteva, Adelina, i Valeria Stoyanova. "Zeolites application in terrestrial and space industry – a review". Aerospace Research in Bulgaria 32 (2020): 209–23. http://dx.doi.org/10.3897/arb.v32.e17.
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This brief overview presents an attempt to systematize some of the available historical and recent data on the impact of zeolite science and engineering on the progress of various areas of Earth and Space development. The basic structural and chemical properties of natural and synthetic zeolites are presented. Valuable applications of the zeolites, such as catalysts, gas adsorbers and ion exchangers are also included. The most commonly used methods for the synthesis of zeolites from different materials are presented, as well as some Bulgarian developments for the reuse of waste materials to zeolites. The important role of zeolites as an indispensable material for improving the quality of soil, fuels, water, air, etc., required for the needs of orbiting space stations and spacecrafts has been confirmed by typical examples.
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Behin, Jamshid, Elmira Ghadamnan i Hossein Kazemian. "Recent advances in the science and technology of natural zeolites in Iran". Clay Minerals 54, nr 2 (24.05.2019): 131–44. http://dx.doi.org/10.1180/clm.2019.19.
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AbstractIran has significant deposits of high-purity natural zeolites. Many Iranian scholars conduct scientific research on porous materials, from natural and synthetic zeolites to metal organic framework materials. Iranian zeolite deposits and associated research are reviewed here. Various industrial applications of natural zeolites, from agriculture to animal husbandry to the construction industry and beyond are discussed here.
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Belviso, Claudia, Giulia Guerra, Maryam Abdolrahimi, Davide Peddis, Federica Maraschi, Francesco Cavalcante, Maurizio Ferretti, Annalisa Martucci i Michela Sturini. "Efficiency in Ofloxacin Antibiotic Water Remediation by Magnetic Zeolites Formed Combining Pure Sources and Wastes". Processes 9, nr 12 (26.11.2021): 2137. http://dx.doi.org/10.3390/pr9122137.
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In this work, red mud (RM) and spinel iron oxide nanoparticles (SPIONs) were added to pure silica/alumina sources (SAs) and fly ash (FA) with the aim of synthesizing and investigating the magnetic behavior of different zeolites. SAs were used to synthesize zeolite with LTA topology (zeolite A) with the addition of both red mud and spinel iron oxide nanoparticles. FA and RM were mixed to synthesize sodalite whereas only FA with the addition of SPIONs was used to form zeolite with FAU-topology (zeolite X). All the synthetic products showed magnetic properties. However, zeolites with spinel iron oxide nanoparticles (zeolites A and X) showed ferromagnetic-like behavior. Sodalite was characterized by a reduction in saturation magnetization, whereas zeolite A with red mud displayed antiferromagnetic behavior. For the first time, all the synthetic products were tested for polluted water remediation by a persistent emerging contaminant, ofloxacin (OFL) antibiotic. The four zeolite types showed good adsorption affinity towards OFL under actual conditions (tap water, natural pH). All materials were also tested for OFL removal in real waters spiked with OFL 10 µg L−1. Satisfactory recoveries (90–92% in tap water, 83–87% in river water) were obtained for the two zeolites synthesized from industrial waste materials.
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Belviso, Claudia, Davide Peddis, Gaspare Varvaro, Maryam Abdolrahimi, Andrea Pietro Reverberi i Francesco Cavalcante. "Obsidian as a Raw Material for Eco-Friendly Synthesis of Magnetic Zeolites". Materials 13, nr 20 (16.10.2020): 4633. http://dx.doi.org/10.3390/ma13204633.
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A sample of rhyolitic obsidian (OS) was used as raw material for zeolite synthesis by long (4 days) and fast (2 h)-aging hydrothermal processes. Zeolite synthesis was also performed by a fast (2 h) sonication method. The products were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) both immediately after and 3 years after their formation in order to determine the stability of synthetic materials according to the method used. The results confirm zeolitization of obsidian both by long-aging conventional hydrothermal heating and fast hydrothermal process. However, the data highlight the efficiency of direct ultrasound energy in achieving more stable zeolite crystals over time. These results carried out using a natural source, follow those already obtained using wastes and pure sources as raw materials thus providing a definitive validation of the different mechanisms controlling zeolite formation according to the process used. Moreover, the results confirm the effectiveness of ultrasonic energy in the formation of zeolites that are more stable over time. Due to the chemical composition of the obsidian precursor, all synthetic zeolites show good magnetic properties (i.e., saturation magnetization), in view to potential magnetic separation.
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Levenets, V. V., A. Yu Lonin, O. P. Omelnik i A. O. Shchur. "Use of mathematical modeling for a comparative assessment of the sorption properties of natural and synthetic zeolites to cobalt". Nuclear Physics and Atomic Energy 22, nr 3 (25.09.2021): 318–23. http://dx.doi.org/10.15407/jnpae2021.03.318.
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Comparison of the sorption capacity of natural zeolite (clinoptilolite) and synthetic zeolites (NaX and NaA) in relation to cobalt ions is done under dynamic conditions. The sorption capacity of zeolites in relation to cobalt was: for clinoptilolite - 59.00 mg/g; for zeolite NaX - 87.03 mg/g; for zeolite NaA - 73.00 mg/g. Based on the data obtained, mathematical modeling of sorption isotherms was carried out using the Langmuir equation, Chebyshev criterion, and the criterion of the least-squares method. The performed correlation of the factual and model results indicates that the considered models adequately reflect the sorption processes taking place in zeolites. The results obtained make it possible to use the considered models for prognostication of the behavior of zeolites with respect to cobalt.
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Imoisili, Patrick Ehi, i Tien Chien Jen. "Microwave-Assisted Synthesis and Characterization of Zeolite Prepared From South Africa Coal Fly Ash". Key Engineering Materials 917 (13.04.2022): 154–59. http://dx.doi.org/10.4028/p-2oxfw6.
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In industry, synthetic zeolites are commonly used as ion-exchange materials, catalyst supports, and adsorbents. As a result, a more energy-efficient alternative for its synthesis from low-cost and accessible raw materials is needed. This study, presents the possibility of using class F South African coal fly ash (SACFA) from Lethaba thermal-power station as a precursor to produce zeolites via a microwave (MW) assisted synthesis route. The mineral content of synthetic materials was determined using X-ray florescence (XRF). Morphology was determined using a Scanning electron microscopy (SEM), elemental composition by energy dispersive spectrometer (EDS). X-ray diffractometry (XRD) was used to get structural characterization. Microwave (MW) irradiation time and intensity enhance the crystallization of the zeolite phase as a result of sufficient energy required to enable the solubility of alumina and silica from coal fly ash. The use of MW irradiation provides a green alternative to zeolite synthesis from fly ash (FA) than traditional thermal and fusion techniques, which uses a great deal of energy consumption and a longer reaction time.
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Giannatou, Spyridoula, Charalampos Vasilatos, Ioannis Mitsis i Nikolaos Koukouzas. "Utilization of natural and synthetic zeolitic materials as soil amendments in abandoned mine sites". Bulletin of the Geological Society of Greece 53, nr 1 (9.10.2018): 78. http://dx.doi.org/10.12681/bgsg.18567.
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The aim of this paper is to evaluate the effects of natural and synthetic zeolitic materials as soil amendments in contaminated soils. Two species of natural zeolites, clinoptilolite and mordenite, sampled from Samos Island, Greece, were used as low-cost modifiers (amendments). Both of these materials show perfect XRD-patterns. Moreover, coal fly ash (CFA) derived from the electrostatic precipitators of the Meliti power plant (Florina, Greece) converted via an alkaline hydrothermal treatment with 1M NaOH was used to produce a synthetic zeolitic material. The mineralogical composition of natural and synthetic zeolites was tested and identified by X-ray diffraction (XRD) and scanning electron microscope (SEM). The amendments and original contaminated soils from a former mining area of Lavrion, were mixed and equilibrated for 1 week, hydrated up to 40% of their water holding capacity. After the equilibration, the growth of Trifolium alexandrinum both in amended and original soils was studied in a pot experiment. The increase in pH value of treated soil by the tested amendments, confirmed the buffering effect and suggested the opportunity of using zeolitic materials for conditioning and remedying contaminated acidic soils from sulphidic mining areas. Moreover, the amended soils exhibited higher CEC values compared with unamended soil. Results showed that the synthetic zeolite produced by Meliti’s power station fly ash, was the most effective for plant growth, among the tested amendments. Between natural zeolitic materials from Samos Island, the most efficient was the clinoptilolite rich, probably because of its better water holding capacity compared with mordenite.
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Alekberov, Y. Z., R. Z. Khalilov i X. G. Ismailova. "Research and application of natural zeolite in the processes of gas purification and drying". SOCAR Proceedings, SI2 (30.12.2021): 16–21. http://dx.doi.org/10.5510/ogp2021si200601.
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This article describes the adsorption capability of natural zeolites for the purification and dehydration of natural gases. Studies were carried out with natural clinoptilolite treated with various cadmium and titanium solutions. Zeolite-containing rocks were used as a natural adsorbent and experiments using a synthetic CaA zeolite were also carried for comparison. The experiments showed that zeolite from the Ai-Dag deposits possesses the highest activity in terms of sulfur compound. Its activity is closer to that of synthetic CaA zeolite. Studies showed that natural zeolites and adsorbents obtained on their basis allow the gas to be dehydrated to a dew point temperature of minus 40-45 °C. This is sufficient to prepare gas for transportation directly from the fields under any climatic conditions. Keywords: gas dehydration; zeolite; adsorbent; sulfur compounds.
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Korpa, A., V. Teneqja, S. Gjyli i A. Andoni. "Parameters Affecting the Synthesis of X and A Zeolites from Coal Fly Ash". European Journal of Environment and Earth Sciences 2, nr 1 (25.02.2021): 53–59. http://dx.doi.org/10.24018/ejgeo.2021.2.1.114.
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This paper summarizes the investigation results on the main parameters affecting the synthesis of type X and A zeolites using coal silicious fly ash (FA) as raw material. The synthesis was performed by dissolution of alkali-fused alumino-silicates, followed by hydrothermal treatment. The experimental data confirm that fly ash SiO2/Al2O3 ratio, NaOH/FA ratio, acid treatment of pre-fused fly ash, salinity of solution have a significant effect on type and properties of newly formed zeolites. In summary, the results show that A and X-type zeolite form with FA SiO2/Al2O3 ratio < 1.12 and > 1.86, respectively. Moreover, FA characterized by SiO2/Al2O3 mole ratio of 3.15 is suitable for X-type zeolite synthesis while A-type zeolite does not form without NaAlO2 addition. The crystallization occurs faster at higher temperatures although above 90°C X-type zeolite evolves into more stable phases whereas increasing the crystallization time from 1 to 72 hours, the yield of the synthetic products enhances from 60 to 75%. The use of seawater is responsible for the synthesis of X-type showing both lower purity and specific surface area. However, the synthetic products are characterized by high exchange capacity (> 320 meq/100 g), thus suggesting their successful application as adsorbents and catalysts in different types of wastewater and industrial waste treatments.
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Hu, Tao, Wenyan Gao, Xin Liu, Yifu Zhang i Changgong Meng. "Synthesis of zeolites Na-A and Na-X from tablet compressed and calcinated coal fly ash". Royal Society Open Science 4, nr 10 (październik 2017): 170921. http://dx.doi.org/10.1098/rsos.170921.
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Zeolites Na-A and Na-X are important synthetic zeolites widely used for separation and adsorption in industry. It is of great significance to develop energy-efficient routines that can synthesize zeolites Na-A and Na-X from low-cost raw materials. Coal fly ash (CFA) is the major residue from the combustion of coal and biomass containing more than 85% SiO 2 and Al 2 O 3 , which can readily replace the conventionally used sodium silicate and aluminate for zeolite synthesis. We used Na 2 CO 3 to replace the expensive NaOH used for the calcination of CFA and showed that tablet compression can enhance the contact with Na 2 CO 3 for the activation of CFA through calcination for the synthesis of zeolites Na-A and Na-X under mild conditions. We optimized the control variables for zeolite synthesis and showed that phase-pure zeolite Na-A can be synthesized with CFA at reactant molar ratio, hydrothermal reaction temperature and reaction time of 1.3Na 2 O: 0.6Al 2 O 3 : 1SiO 2 : 38H 2 O at 80°C for 6 h, respectively, while phase-pure zeolite Na-X can be synthesized at 2.2Na 2 O: 0.2Al 2 O 3 : 1SiO 2 : 88H 2 O at 100°C for 8 h, respectively. The composition, morphology, specific surface area, vibration spectrum and thermogravimetry of synthesized Na-A and Na-X were further characterized.
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Ngapa, Yulius Dala, Sri Sugiarti i Zaenal Abidin. "Hydrothermal Transformation of Natural Zeolite from Ende-NTT and Its Application as Adsorbent of Cationic Dye". Indonesian Journal of Chemistry 16, nr 2 (13.03.2018): 138. http://dx.doi.org/10.22146/ijc.21156.
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A synthetic zeolite was produced from natural zeolite from Ende-Nusa Tenggara Timur (NTT) by hydrothermal method. This study aims to produce synthetic zeolite from Ende natural zeolite to remove cation dye through the adsorption process. Temperature of crystal formation (ageing) was performed at 60 °C for 6 h and hydrothermal process was at 100 °C for 24 h. The natural zeolite produced synthetic NaP1 and synthetic Faujasite. Based on the research results, the synthesis of zeolite by the hydrothermal method can enhance the adsorption capacity and Cation Exchange Capacity (CEC). The adsorption capacity in the natural zeolites of type ZG, ZL and ZC before the hydrothermal process were 17.289, 17.276, and 16.483 mg/g, respectively, and after hydrothermal they increased to 37.398, 37.369 and 37.362 mg/g, respectively. In addition, the CEC increased from 84.154, 81.042, and 77.474 cmol/kg, respectively, to 244.063, 216.354, and 211.432 cmol/kg, respectively. The Langmuir model most closely matched the isothermal adsorption equilibrium process.
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Hudec, P., J. Novanský, S. Silhár, T. N. Trung, M. Zúbek i J. Maďar. "Possibility of Using t-Plots, Obtained from Nitrogen Adsorption for the Valuation of Zeolites". Adsorption Science & Technology 3, nr 3 (wrzesień 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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Ferella, Francesco, Valentina Innocenzi, Nicold M. Ippolito i Ida De Michelis. "Adsorption of CO2 by synthetic zeolites". E3S Web of Conferences 161 (2020): 01116. http://dx.doi.org/10.1051/e3sconf/202016101116.
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The paper reports on a possible way to recycle fluid catalytic cracking catalysts (FCCCs), widely used in oil refining operations. This research proposes a novel approach that leads to a near zero-waste process. The spent FCCC was leached by 1.5 mol/L of HNO3, HCl and H2SO4 solutions at 80°C, for 3 h with a solid to liquid ratio of 20 %wt/vol. The leaching yields for cerium and lanthanum were in the range 69-82 %. The solid residues from the leaching stage were used as base material for the synthesis of the zeolites by means of a combined thermal-hydrothermal treatment. The characterization of the zeolites demonstrated that the Na-A phase was predominant over the Na-X phase. The zeolites were tested as sorbent material for CO2 separation from CH4, in order to simulate the upgrading of biogas to biomethane. The maximum adsorption rate of CO2 was 0.778 mol CO2/kg of zeolite at 3 bar, with a resulting CH4 recovery of 62 % and purity of 97 %vol. The zeolites synthesized from spent FCCC represent a feasible solution to recover such industrial waste.
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Mlekodaj, Kinga, Joanna E. Olszowka, Venceslava Tokarova, Edyta Tabor, Ales Kasparek, Jana Novakova, Gabriela Stavova i in. "Effect of Alkali-Free Synthesis and Post-Synthetic Treatment on Acid Sites in Beta Zeolites". Molecules 25, nr 15 (28.07.2020): 3434. http://dx.doi.org/10.3390/molecules25153434.
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Beta zeolites with Si/Al around 14 were prepared using three new alkali-free synthesis methods based on the application of amorphous aluminosilicate precursor and calcined in ammonia or air. All samples exhibit structural and textural properties of standard beta zeolite. Comprehensive study by 27Al and 29Si MAS NMR, together with FTIR adsorption of d3-acetonitrile and pyridine were used to characterize the influence of both the synthesis and calcination procedure on the framework Al atoms and related Brønsted and Lewis acid sites. While calcination in ammonia preserves all framework Al atoms, calcination in air results in 15% release of framework Al, but without restrictions of the accessibility of the beta zeolite channel system for bulky pyridine molecules. Terminal (SiO)3AlOH groups present in the hydrated zeolites were suggested as a precursor of framework Al-Lewis sites. Surprisingly, the mild dealumination of the air-calcined zeolites result in an increase of the concentration of Brønsted acid sites and a decrease of the total concentration of Lewis sites with the formation of the extra-framework ones.
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Kerr, George T. "Synthetic Zeolites". Scientific American 261, nr 1 (lipiec 1989): 100–109. http://dx.doi.org/10.1038/scientificamerican0789-100.
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Akinruli, Ifedayo Joshua, Seun Samuel Owoeye, Segun Michael Abegunde, Ayodeji E. Onipede i 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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Kowalak, S., i A. Zywert. "Preparation of Maya Blue analogues using natural zeolites". Clay Minerals 46, nr 2 (czerwiec 2011): 197–204. http://dx.doi.org/10.1180/claymin.2011.046.2.197.
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AbstractPigments similar to the famous Maya Blue were prepared by entrapment of indigo inside the channels of natural zeolites such as clinoptilolite and mordenite. The zeolites were mixed and ground with indigo and then heated at 150°C. Surplus (unbound) dye was removed by solvent extraction or by vacuum sublimation. As is the case when synthetic zeolites are used as matrices, the colouration of the resulting pigments could be modified by the previous cation exchange of the zeolite.
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Król, Magdalena, Andrzej Koleżyński i Włodzimierz Mozgawa. "Vibrational Spectra of Zeolite Y as a Function of Ion Exchange". Molecules 26, nr 2 (11.01.2021): 342. http://dx.doi.org/10.3390/molecules26020342.
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Zeolite Y is one of the earliest known and most widely used synthetic zeolites. Many experimental investigations verify the valuable ion exchange capability of this zeolite. In this study, we assessed the effects of ion exchange on its vibrational spectra. We applied classical lattice dynamics methods for IR and Raman intensity calculations. Computed spectra of optimized zeolite Y structures with different cations were compared with experimental data. The spectra obtained in this study are in agreement with previous experimental and computational studies on zeolites from the faujasite group.
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Król, Magdalena, Andrzej Koleżyński i Włodzimierz Mozgawa. "Vibrational Spectra of Zeolite Y as a Function of Ion Exchange". Molecules 26, nr 2 (11.01.2021): 342. http://dx.doi.org/10.3390/molecules26020342.
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Zeolite Y is one of the earliest known and most widely used synthetic zeolites. Many experimental investigations verify the valuable ion exchange capability of this zeolite. In this study, we assessed the effects of ion exchange on its vibrational spectra. We applied classical lattice dynamics methods for IR and Raman intensity calculations. Computed spectra of optimized zeolite Y structures with different cations were compared with experimental data. The spectra obtained in this study are in agreement with previous experimental and computational studies on zeolites from the faujasite group.
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Dang, Long Van, Thu Thi Minh Nguyen, Dang Van Do, Son Thanh Le, Trong Dinh Pham i Anh Thi Mai Le. "Study on the Synthesis of Chabazite Zeolites via Interzeolite Conversion of Faujasites". Journal of Analytical Methods in Chemistry 2021 (29.03.2021): 1–10. http://dx.doi.org/10.1155/2021/5554568.
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The interzeolite conversion of faujasite (FAU-type) zeolites to chabazite (CHA-type) zeolite in the presence of N,N,N-trimethyladamantammonium and N,N,N-dimethylethylcyclohexylammonium cations was investigated over a large compositional range by carefully controlling the reaction mixture compositions. Highly crystalline CHA zeolites were also obtained by the transformation of several zeolite types including EMT, LTL, LEV, RTH, and MFI frameworks. The formation of CHA zeolite from FAU zeolite precursors was substantially faster than that from zeolite L with a similar composition. High-silica CHA zeolites were also produced successfully using a mixture of TMAda with a number of less expensive organic structure-directing agents. The CHA zeolite materials have been synthesized with high crystallinity and with a Si/Al ratio ranging from 5 to 140. Our data support the importance of structural similarity between the zeolite precursors, nucleation/crystallization processes, and the zeolite product in the interzeolite conversion compared to conventional amorphous aluminosilicate gels. Our synthetic methods could be used to prepare other 8-membered ring zeolites such as AEI and AFX frameworks, potential candidates for selective catalytic reduction of NOx, light olefin production, and CO2 abatement.
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Etz, Edgar S. "Exploratory Investigation of Synthetic Zeolites by Near-Infrared Fourier-Transform Raman Microspectroscopy". Microscopy and Microanalysis 3, S2 (sierpień 1997): 861–62. http://dx.doi.org/10.1017/s1431927600011193.
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Zeolites are complex, three-dimensional, hydrated crystalline aluminosilicates that have porous structures with channels or cages of various dimensions. In the simplest way they can be represented by (Na2,K,Ca,Ba) [(Al,Si)O2]nxH2O. They may be either of natural or synthetic origin. As high-surface-area materials, they take on great technological importance, foremost in surface science and catalysis. The structure of the zeolite is critical to its function. Structure information is commonly obtained by x-ray and neutron diffraction, NMR, IR, and Raman spectroscopy techniques. Synthetic zeolites are produced in enormous quantities worldwide and are key to critical technologies. Yet, no real zeolite standards exit that are defined and certified. NIST, with input from industry and academia, has begun a measurement program to certify various physico-chemical properties for a suite of synthetic zeolite powder standard reference materials (SRMs) and research materials (RMs). These proposed "standard" zeolite materials span a range of pore sizes, SiO2/Al2O3 ratios, ring sizes, structural building units, and cage sizes.
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Belviso, Claudia, Antonio Satriani, Stella Lovelli, Alessandro Comegna, Antonio Coppola, Giovanna Dragonetti, Francesco Cavalcante i Anna Rita Rivelli. "Impact of Zeolite from Coal Fly Ash on Soil Hydrophysical Properties and Plant Growth". Agriculture 12, nr 3 (2.03.2022): 356. http://dx.doi.org/10.3390/agriculture12030356.
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Zeolites can be extensively employed in agricultural activities because they improve soil properties such as infiltration rates, saturated hydraulic conductivity, water holding capacity, and cation exchange capacity. Natural and synthetic zeolites can efficiently hold water. Zeolites are also believed to have the ability to lose and gain water reversibly, without changing their crystal structure. In the present study, several laboratory tests were carried out using: (i) zeolite synthesized from coal fly ash (a waste product from burning coal in thermoelectric power plants), (ii) a silty loam soil, typically found in Southern Italy, and (iii) sunflower as a reference plant. The selected soil was amended with different percentages of zeolite (1, 2, 5, and 10%) and the effects of the synthetic mineral addition on the hydrophysical properties of the soil and plant growth were evaluated. The results indicated that soil–zeolite mixtures retained water more efficiently by pore radius modification. However, this causes a variation in the range of plant-available water towards higher soil humidity values, as the amount of added zeolite increases. These data confirm that zeolite addition modifies the selected hydrophysical properties of the soil with the effect of decreasing the soil drainage capacity, making the soil less habitable for plant growth.
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Yu, Seung-Hye, Manjesh Kumar, Il Won Kim, Jeffrey D. Rimer i Tae-Jung Kim. "A Comparative Analysis of In Vitro Toxicity of Synthetic Zeolites on IMR-90 Human Lung Fibroblast Cells". Molecules 26, nr 11 (26.05.2021): 3194. http://dx.doi.org/10.3390/molecules26113194.
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Broad industrial application of zeolites increases the opportunity of inhalation. However, the potential impact of different types and compositions of zeolite on cytotoxicity is still unknown. Four types of synthetic zeolites have been prepared for assessing the effect on lung fibroblast: two zeolite L (LTL-R and LTL-D), ZSM-5 (MFI-S), and faujasite (FAU-S). The cytotoxicity of zeolites on human lung fibroblast (IMR-90) was assessed using WST1 cell proliferation assay, mitochondrial function, membrane leakage of lactate dehydrogenase, reduced glutathione levels, and mitochondrial membrane potential were assessed under control. Intracellular changes were examined using transmission electron microscopy (TEM). Toxicity-related gene expressions were evaluated by PCR array. The result showed significantly higher toxicity in IMR-90 cells with FAU-S than LTL-R, LTL-D and MFI-S exposure. TEM showed FAU-S, spheroidal zeolite with a low Si/Al ratio, was readily internalized forming numerous phagosomes in IMR-90 cells, while the largest and disc-shaped zeolites showed the lowest toxicity and were located in submembranous phagosomes in IMR-90 cells. Differential expression of TNF related genes was detected using PCR arrays and confirmed using qRT-PCR analysis of selected genes. Collectively, the exposure of different zeolites shows different toxicity on IMR-90 cells.
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Gangele, Richa, Priya Pawaiya i Yogesh Pandey. "Synthetic Zeolites- Structure Properties and Application Area". International Journal of Scientific Research 3, nr 6 (1.06.2012): 78–80. http://dx.doi.org/10.15373/22778179/june2014/29.
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Ke, Guojun, Haichen Shen i Pengfei Yang. "Synthesis of X-Zeolite from Waste Basalt Powder and its Influencing Factors and Synthesis Mechanism". Materials 12, nr 23 (26.11.2019): 3895. http://dx.doi.org/10.3390/ma12233895.
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Traditional hydrothermal method (TH) and alkali fusion-assisted hydrothermal method (AFH) were evaluated for the preparation of zeolites from waste basalt powder by using NaOH as the activation reagent in this study. The synthesized products were characterized by BET, XRD, FTIR and SEM. The effects of acid treatment, alkali/basalt ratio, calcination temperature and crystallization temperature on the synthesis process were studied. The results showed that AFH successfully synthesized zeolite X with higher crystallinity and no zeolite was formed by TH. The specific surface area of synthetic zeolite X was 486.46 m2·g−1, which was much larger than that of original basalt powder (12.12 m2·g−1). Acid treatment and calcination temperature had no effect on zeolite types, but acid treatment improved the yield and quality of zeolite. Alkali/basalt ratio and crystallization temperature not only affected the crystallinity of synthesized zeolites but also affected its type. The optimum synthesis condition of zeolite X are as follows: acid treatment of 5 wt% HCl solution, NaOH/basalt ratio of 1:1, a calcination temperature of 650 °C and crystallization temperature of 120 °C. The work shows that basalt can be used as a raw material to prepare zeolite.
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Hussain, Tabassum, Abdullah Ijaz Hussain, Shahzad Ali Shahid Chatha, Adnan Ali, Muhammad Rizwan, Shafaqat Ali, Parvaiz Ahamd, Leonard Wijaya i Mohammed Nasser Alyemeni. "Synthesis and Characterization of Na-Zeolites from Textile Waste Ash and Its Application for Removal of Lead (Pb) from Wastewater". International Journal of Environmental Research and Public Health 18, nr 7 (24.03.2021): 3373. http://dx.doi.org/10.3390/ijerph18073373.
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Massive production of carcinogenic fly ash waste poses severe threats to water bodies due to its disposal into drains and landfills. Fly ash can be a source of raw materials for the synthesis of adsorbents. Rag fly ash as a new class of raw materials could be a cheap source of Al and Si for the synthesis of Na-zeolites. In this work, NaOH activation, via a prefusion- and postfusion-based hydrothermal strategy, was practiced for the modification of rag fly ash into Na-zeolite. Morphology, surface porosity, chemical composition, functionality, mineral phases, and crystallinity, in conjunction with ion exchangeability of the tailored materials, were evaluated by SEM, ICP-OES, XRF, FTIR, XRD, and cation exchange capacity (CEC) techniques. Rag fly ash and the synthesized Na-zeolites were applied for the removal of Pb (II) from synthetic wastewater by varying the reaction conditions, such as initial metal ion concentration, mass of adsorbent, sorption time, and pH of the reaction medium. It was observed that Na-zeolite materials (1 g/100 mL) effectively removed up to 90–98% of Pb (II) ions from 100 mg/L synthetic solution within 30 min at pH ≈ 8. Freundlich adsorption isotherm favors the multilayer heterogeneous adsorption mechanism for the removal of Pb (II). It is reasonable to conclude that recycling of textile rag fly ash waste into value-added Na-zeolites for the treatment of industrial wastewater could be an emergent move toward achieving sustainable and green remediation.
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Urminská, Barbora, Ján Derco, Ronald Zakhar i Adriana Korpicsová. "Use of zeolites for macronutrients removal from wastewater". Acta Chimica Slovaca 12, nr 1 (1.04.2019): 150–61. http://dx.doi.org/10.2478/acs-2019-0021.
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Abstract Natural or synthetic zeolites have unique physical, chemical and structural properties that predetermine their use in many processes, including wastewater treatment. This study presents the results of our preliminary research in the field of nitrogen and phosphorus removal using adsorption and adsorptive ozonation with natural and modified zeolites. Iron-modified zeolite was the most efficient for the removal of ammonium nitrogen by adsorption. Phosphorus removal efficiency using adsorption was relatively low and natural zeolite was not suitable for the phosphorus removal at all. Ozone had no significant impact on the removal efficiency. Regeneration of loaded zeolites with ozone has also been studied. This method was partly efficient but it needs be further examined.
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Nowak, Paulina, Barbara Muir, Agnieszka Solińska, Małgorzata Franus i Tomasz Bajda. "Synthesis and Characterization of Zeolites Produced from Low-Quality Coal Fly Ash and Wet Flue Gas Desulphurization Wastewater". Materials 14, nr 6 (22.03.2021): 1558. http://dx.doi.org/10.3390/ma14061558.
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This study investigated a low-energy-consuming procedure for the synthesis of zeolite materials from coal fly ash (CFA). Materials containing zeolite phases, namely Na–X, Na–P1, and zeolite A, were produced from F–class fly ash, using NaOH dissolved in distilled water or in wastewater obtained from the wet flue gas desulphurization process, under atmospheric pressure at a temperature below 70 °C. The influence of temperature, exposure time, and alkaline solution concentration on the synthesized materials was tested. In addition, chemical, mineralogical, and textural properties of the obtained materials were determined by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and cation exchange capacity (CEC). Cd(II), Ni(II), NH4+ cation, and Se(VI) anion sorption experiments were conducted to compare the sorption properties of the produced synthetic zeolites with those of the commercially available ones. Zeolitization resulted in an increase of CEC (up to 30 meq/100 g) compared to raw CFA and enhanced the ability of the material to adsorb the chosen ions. The obtained synthetic zeolites showed comparable or greater sorption properties than natural clinoptilolite and synthetic Na–P1. They were also capable of simultaneously removing cationic and anionic compounds. The structural, morphological, and textural properties of the final product indicated that it could potentially be used as an adsorbent for various types of environmental pollutants.
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Chen, Huei-Fen, Yi-Jun Lin, Bo-Hong Chen, Iizuka Yoshiyuki, Sofia Liou i Rong-Tan Huang. "A Further Investigation of NH4+ Removal Mechanisms by Using Natural and Synthetic Zeolites in Different Concentrations and Temperatures". Minerals 8, nr 11 (1.11.2018): 499. http://dx.doi.org/10.3390/min8110499.
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We investigated the ammonium removal abilities of natural and synthetic zeolites with distinct Si/Al ratios and various surface areas to study how adsorption and ion exchange processes in zeolites perform under different ammonium concentrations and different temperatures. Five zeolites—natural mordenite, chabazite, erionite, clinoptilolite, and synthetic merlinoite—were immersed in 20, 50, and 100 mg/kg ammonium solutions. The results demonstrate that zeolites under high ammonium concentrations (100 mg/kg) possess higher physical adsorption capacity (0.398–0.468 meq/g), whereas those under lower ammonium concentrations (20 mg/kg) possess greater ion exchange properties (64–99%). The ion exchange ability of zeolites is extremely dependent on the cation content of the zeolites, and the cation content is affected by the Si/Al ratio. The surface area of zeolites also has a partial influence on its physical adsorption ability. When the surface area is less than 100 m2/g, the adsorption ability of zeolite increases obviously with surface area; however, adsorption ability is saturated as the surface area becomes larger than this critical value of 100 m2/g. When we placed the zeolites in 50 mg/kg ammonium concentration at different temperatures (5–50 °C), we found that the zeolites exhibited the highest ammonium removal ability at 30 °C and the potassium release was enhanced at 30–40 °C.
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Liu, Zhendong, Kotatsu Okabe, Chokkalingam Anand, Yasuo Yonezawa, Jie Zhu, Hiroki Yamada, Akira Endo i in. "Continuous flow synthesis of ZSM-5 zeolite on the order of seconds". Proceedings of the National Academy of Sciences 113, nr 50 (28.11.2016): 14267–71. http://dx.doi.org/10.1073/pnas.1615872113.
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The hydrothermal synthesis of zeolites carried out in batch reactors takes a time so long (typically, on the order of days) that the crystallization of zeolites has long been believed to be very slow in nature. We herein present a synthetic process for ZSM-5, an industrially important zeolite, on the order of seconds in a continuous flow reactor using pressurized hot water as a heating medium. Direct mixing of a well-tuned precursor (90 °C) with the pressurized water preheated to extremely high temperature (370 °C) in the millimeter-sized continuous flow reactor resulted in immediate heating to high temperatures (240–300 °C); consequently, the crystallization of ZSM-5 in a seed-free system proceeded to completion within tens of or even several seconds. These results indicate that the crystallization of zeolites can complete in a period on the order of seconds. The subtle design combining a continuous flow reactor with pressurized hot water can greatly facilitate the mass production of zeolites in the future.