Дисертації з теми "Synthetic Zeolites"
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Amin, S. "Surface barriers on synthetic zeolites." Thesis, University of Salford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291648.
Повний текст джерелаSulaiman, Shamsul Kamal. "Preparation of synthetic zeolites from aluminosilicate materials." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427789.
Повний текст джерелаWilliams, C. D. "Use of synthetic zeolites as slow release agents." Thesis, University of Salford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381713.
Повний текст джерелаBrace, Shelley. "Synthetic and structural studies of high silica MFI zeolites." Thesis, Keele University, 2017. http://eprints.keele.ac.uk/3778/.
Повний текст джерелаKini, Gautam Chandrakanth. "Characterization of synthetic zeolites optimized for heavy metal uptake from wastewater." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0015769.
Повний текст джерелаHolmes, Amy Elizabeth. "Synthetic and atomic force microscopy studies of offretite/erionite family zeolites." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/synthetic-and-atomic-force-microscopy-studies-of-offretiteerionite-family-zeolites(476728ac-6294-44e9-9ac7-b2abcef04b0b).html.
Повний текст джерелаHui, Kwan San. "Recycling of coal fly ash : synthetic zeolite 4A and MCM-41 /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?MECH%202004%20HUI.
Повний текст джерелаTian, Yuyang. "Synthesis and characterization of crystalline microporous materials : investigation of new synthetic routes." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6371.
Повний текст джерелаRebedea, Irina. "An investigation into the use of synthetic zeolites for in situ land reclamation." Thesis, Liverpool John Moores University, 1997. http://researchonline.ljmu.ac.uk/5562/.
Повний текст джерелаWhitehead, Kate. "The application of synthetic zeolites for the removal of heavy metals from contaminated effluents." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/771884/.
Повний текст джерелаHart, R. "The potential use of synthetic faujasite zeolites as slow release ammonium and potassium fertilizers." Thesis, City University London, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375831.
Повний текст джерелаSimancas, Coloma Jorge. "Synthesis and Characterization of Zeolitic Materials Using Phosphorous Organic Structure Directing Agents." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/171267.
Повний текст джерела[CA] Les zeolites són materials cristal·lins microporosos amb canals i mides de porus de dimensions moleculars. L'estructura i composició de les zeolites els confereix interessants propietats que permeten la seua aplicació en una àmplia gamma d'aplicacions industrials com adsorció, separació o catàlisi. La síntesi de zeolites és l'etapa més important per al control de l'estructura i composició de les zeolites i, per tant, crítica per a l'optimització de les seues propietats. Aquesta tesi s'ha centrat en la síntesi de zeolites utilitzant compostos que contenen fòsfor (cations fosfoni i aminofosfoni) com a agents directors d'estructura (P-ADE). L'ús de compostos fosforats influeix en la cristal·lització i propietats de les zeolites obtingudes en comparació amb les zeolites obtingudes amb cations d'amoni clàssics. Els compostos fosforats es van triar a causa de la seua diferent química i estabilitat pel que fa als cations d'amoni clàssics utilitzats en la síntesi de zeolites. Aquests aspectes s¿estudiaren amb un estudi comparatiu de diferents cations d'amoni i fosforats. Els compostos de fòsfor utilitzats en aquest treball han donat lloc a noves estructures cristal·lines (ITQ-58 i ITQ-66) i han obert noves vies de síntesi de zeolites ja conegudes (RTH, IWV i DO), ampliant la seua gamma de composicions químiques. La descomposició tèrmica dels P-ADE atrapats dins de les zeolites dona lloc a la for-mació d'espècies de fòsfor extra-xarxa que romanen dins dels canals i cavitats de les zeolites. Aquestes espècies modulen les propietats àcides i d'adsorció dels materials finals depenent dels tractaments post-síntesi. En aquest treball s'ha estudiat una ruta per la incorporació de quantitats controlades de fòsfor durant l'etapa de síntesi. Això ha permés controlar l'adsorció i les propietats àcides en les zeolites de porus petit, el que no es pot aconseguir mitjançant metodologies de post-síntesi.
[EN] Zeolites are microporous crystalline materials with channels and pore openings of molecular dimensions. The structure and composition of zeolites confers them interesting properties that allow their application in a wide range of industrial applications as adsorption, separation or catalysis. The synthesis of zeolites is the most important stage to control the structure and composition of zeolites, and thus, critical to optimize their properties. This thesis has been focused on the synthesis of zeolites using phosphorous containing compounds (phosphonium and aminophosphonium cations) as Organic Structure Directing Agents (P-OSDA). The use of these phosphorous compounds influence the crystallization and properties of the obtained zeolites compared to zeolites obtained with classical ammo-nium cations. Phosphorous compounds were chosen because of their different chemistry and stabil-ity properties respect to classical ammonium cations commonly used in the synthesis of zeo-lites. These aspects were studied in a comparative study with different ammonium and phosphorous cations. The phosphorous compounds used in this work have yielded new crystalline structures (ITQ-58 and ITQ-66) and opened new routes for the synthesis of already known zeolites (RTH, IWV and DON), widening their chemical composition range. The thermal decomposition of the P-OSDAs entrapped inside the zeolites yields to the formation of extra-framework phosphorus species that remain inside the channels and voids of the zeolites. These species modulate the adsorption and acid properties of the final materials depending on the post-synthesis treatments. In this work, a route for the incorporation of controlled amounts of phosphorus during the synthesis stage has been studied. This has allowed to control the adsorption and acid properties in small pores zeolites, which cannot be achieved by post-synthesis methodologies.
I wish to firstly acknowledge the Spanish Government for the necessary funding for the FPI pre-doctoral fellowship (BES-2013-062999). Also, this thesis would not have been possible without the infrastructures provided by the UPV and the CSIC staff, fused into the ITQ. Furthermore, I want to acknowledge the Microscopy Service of the UPV for their support in sample microscopy characterization
Simancas Coloma, J. (2021). Synthesis and Characterization of Zeolitic Materials Using Phosphorous Organic Structure Directing Agents [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171267
TESIS
Zaitceva, Olesia. "Development of new synthetic tools for the preparation of coumarins and thiocoumarins." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF014.
Повний текст джерелаThe first separation of coumarin was made in 1820, since then scientists extracted more than a thousand natural coumarins and came up with many ways to synthesize them. Coumarins have found application in pharmaceutics, medicine, optical chemistry and biochemistry. Thiocoumarins are poorly represented in the literature than coumarins, but find application in similar areas. Due to a wide range of applications of coumarins and great potential of thiocoumarins, we decided to search for effective methods for synthesizing these compounds. The main goal of our study relies on the development of new methods for preparing coumarin and thiocoumarin derivatives starting from acetylenic compounds. The work is divided into the development of two strategies: homogeneous catalysis with a platinum complex and parallel to heterogeneous catalysis with acidic zeolites. According to the results it was possible to reveal the conditions for the cyclization of O- and S- arylpropynoates to coumarins and thiocoumarins. Although it was shown that the Pt (II) complex (PyPhPtCl(MeCN)) acts to cyclize O-arylpropynoates into coumarins, zeolites (H-Y, H-USY) are effective acid catalysts for access not only to coumarins, but also to thiocoumarins
Boruntea, Cristian-Renato. "Design, synthesis and characterization of small-pore zeolites for industrial environmental applications." Doctoral thesis, Universitat Politècnica de València, 2020. http://hdl.handle.net/10251/141094.
Повний текст джерела[CAT] El Projecte d'investigació aquí descrit s'estructura en dos parts. La primera part se centra en la investigació fonamental amb l'objectiu de crear un protocol per a la síntesis de zeolites. La segona part es refereix al disseny, síntesis i caracterització de noves zeolites, particularment útils per a aplicacions DeNOx , però també podria ser útil per a aplicacions MTO. La investigació fonamental suggereix un nou model de preparació de zeolites utilitzant altres zeolites com a llavor. Aquest procés s'anomena transformació zeolita-zeolita o també conversió interzeolita. L'alt rendiment obtingut, la ràpida cristal·lització i la millor utilització i rendiment dels materials de partida s'han tingut en compte per millorar el procés en base a un projecte de doctorat finançat per una empresa. Aquest mètode s'ha il·lustrat utilitzant diverses zeolites com a llavor, entre altres FAU i CHA, per a la preparació de les dues zeolites objectiu: AEI i AFX. A la segona part, la investigació se centra en el disseny de noves zeolites de porus mitjà. S'han seleccionat tres zeolites hipotètiques d'una base de dades de 933.611 estructures. Aquesta selecció s'ha realitzat utilitzant descriptors específicament dissenyats sobre la base de l'aplicabilitat d'aquestes zeolites en processos DeNOx zeolites. A continuació s'han buscat els agents directors d'estructura (ADE) més apropiats, amb l'ajuda de mètodes computacionals, alguns dels quals s'han sintetitzat posteriorment. L'ús d'aquests ADE al gel de síntesi ha permès l'obtenció d'una zeolita la topologia (ERI) ha estat identificada mitjançant anàlisi per PXRD, i la morfologia i mida de vidre (particularment petit) la fan molt adequada per al seu ús com a catalitzador en alguns processos. El treball de síntesi també va revelar l'aparició d'una nova zeolita d'alta densitat, anomenada 'paracelsio-K'. Aquest nou material s'ha obtingut a explorar l'espai de fases que cristal·litzen en utilitzar 1-methyl-DABCO com ADE. La síntesi d'aquesta zeolita té un especial interès perquè el ADE no s'incorpora en els canals de la zeolita, però més aviat influint en la nucleació i cristal·lització. La caracterització va revelar que la composició del material és propera al mineral microcline, estructuralment proper al paracelsio, tots dos feldspats. A diferència dels feldspats el paracelsio-K conté molècules d'aigua al seu interior (1 molècula per cavitat) i pot descriure com el material més simple de la família de les zeolites que conté cadenes del tipus 'doble-cigonyal'. Utilitzant els elements topològics corresponents a aquesta estructura és possible generar estructures zeolítiques ja conegudes, com GIS, APC, MER, PHI, SIV i algunes altres zeolites hipotètiques.
[EN] The research project described herein is structured in two parts. The first part is focused on the fundamental research with the aim of creating a toolbox for zeolite preparation. The second part deal with the design, synthesis and characterization of novel zeolites particular useful for DeNOx applications, but could be also useful for MTO applications. The fundamental research is addressing a novel approach of preparing zeolites by using other zeolites as raw materials. This process is known as zeolite-to-zeolite transformation or interzeolite conversion. The high yield obtained, fast crystallization time and the better utilization of the raw materials (e.g. parent zeolite, organic structure directing agent (OSDA)), are important benefits of interzeolite conversion technic, which answer the objectives formulated for an industrial PhD project. The method has been exemplified by using various raw materials as parent zeolites, such as FAU and CHA for the preparation of two target small pore zeolites AEI and AFX. In the second part the focus has been on the design of novel small pore zeolites. Three hypothetical frameworks have been selected by narrowing down a database containing 933611 structures. The selection has been performed by using the general descriptors for the state-of-the-art DeNOx zeolites (e.g. CHA). This was followed by finding suitable OSDAs for the selected frameworks, by using computational methods. The usage of the theoretically predicted OSDAs in synthesis gels made possible the synthesis of a novel high-silica zeolite. PXRD analysis, revealed that the zeolite has the ERI framework topology. The obtained material has a distinct particle morphology and smaller crystallites, which are key parameters for various catalytic processes. The synthesis work revealed also a novel dense zeolite, named K-paracelsian. The new material has been obtained while exploring the phase space using 1-methyl-DABCO as OSDA. The synthesis of this zeolite is especially interesting in the sense that the OSDA is not being incorporated into the zeolite channels, but rather influencing the nucleation and crystallization. Further characterization revealed a material compositionally closely related to the mineral microcline and structurally closely related to the mineral paracelsian, both of which are feldspars. In contrast to the feldspars, K-paracelsian contains intrazeolitic water corresponding to one molecule per cage and can be described as the simplest endmember of a family of dense double-crankshaft zeolite topologies. By applying the identified building principle, a number of known zeolite frameworks (e.g. GIS, APC, MER, PHI, SIV) and hypothetical zeolite topologies can be constructed.
The authors thank Haldor Topsoe A/S and Innovation Fund Denmark for financial support under the Industrial PhD programme (Case no. 1355-0174B). We thank MINECO of Spain for funding (SEV-2016- 0683 and RTI2018-101033-B-100) and ASIC-UPV for the use of computational facilities. We also thank Prof. M. M. J. Treacy for assistance with the Database of Prospective Zeolite Structures.
Boruntea, C. (2020). Design, synthesis and characterization of small-pore zeolites for industrial environmental applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/141094
TESIS
Barquist, Karna Nicole Larsen Sarah C. "Synthesis and environmental adsorption applications of functionalized zeolites and iron oxide/zeolite composites." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/334.
Повний текст джерелаBarquist, Karna Nicole. "Synthesis and environmental adsorption applications of functionalized zeolites and iron oxide/zeolite composites." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/334.
Повний текст джерелаCornelius, Mero-Lee Ursula. "The role of aluminium content in the control of the morphology of fly ash based hierarchical zeolite X." University of the Western Cape, 2015. http://hdl.handle.net/11394/5232.
Повний текст джерелаCoal is the main source of electricity in South Africa, the combustion of which produces a large amount of waste (coal fly ash) annually. The large-scale generation of coal fly ash places major strain on landfills and the material is toxic in nature. The high silicon and aluminium content in fly ash makes it a suitable starting material for zeolite synthesis. Utilisation of fly ash as a starting material for zeolite synthesis alleviates an environmental burden by converting a waste product to an industrially applicable material. In this study, hierarchical zeolite X was synthesised from coal fly ash via the fusion method. The clear fused fly ash (FFA) extract (with molar composition 0.12 Al·14.6 Na·1.00 Si·163 H₂O) served as the synthesis solution for hydrothermal treatment. The influence of synthesis parameters (such as Si/Al ratio, aluminium source, hydrothermal temperature and stirring) on hierarchical zeolite X formation was studied to determine the cause behind the formation of this material. Synthesised zeolites and starting materials (Arnot coal fly ash and fused fly ash) were characterised by various analytical techniques such as XRD and SEM-EDS to determine the phase purity, morphology and elemental composition (framework Si/Al ratio) of these materials. The synthesis of hierarchical zeolite X under hydrothermal conditions was found to be highly sensitive to the aluminium content of the synthesis solution. The hierarchical morphology of zeolite X was formed preferentially in relatively aluminium-deficient (i.e. high Si/Al ratio) synthesis environments under stirred hydrothermal conditions of 90 °C for 16 hours. In the case of sodium aluminate addition, octahedral shaped zeolite X crystals were formed in relatively low Si/Al ratio synthesis environments, which was attributed to the presence of excess sodium cation content in the synthesis solution. Selected hierarchical zeolites (D2 and E2) were characterised further to gain more insight into the properties of this material. HR-TEM and FTIR revealed that hierarchical zeolite D2 and E2 exhibited the typical structural features of zeolite X. Zeolite D2 and E2 contained both micropores and mesopores and had a high BET surface area of 338-362 m²/g. These zeolites also exhibited appreciable solid acidity (0.81-1.12 mmol H/g zeolite). These properties make hierarchical zeolite X a favourable material for application in catalysis or adsorption. Overall, the formation of zeolite X with hierarchical morphology was proposed to be linked to the presence of zeolite P1 structural units in the framework of the zeolite.
National Research Foundation
Folifac, Leo. "Performance of zeolite ZSM-5 synthesised from South African fly ash in the conversion of methanol to hydrocarbons." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2751.
Повний текст джерелаZeolites have found applications as heterogeneous or solid catalyst in the petrochemical and refining industries. Zeolite ZSM-5 in particular is a highly siliceous solid catalyst with a porous network that consists of medium pore structure (pore openings 5-5.5 A). The solid catalyst (ZSM-5) is well known for its high temperature stability and strong acidity, which makes it an established catalyst used for different petrochemical processes such as Methanol-To-Gasoline (MTG), isomerisation, disproportionation, and cracking. Unlike in the past, the synthesis of zeolite ZSM-5 from other sources that contains silica (Si) and alumina (Al) with the addition of a template (TPBr) as a structure-directing agent is eminent. Its synthesis can be achievable from coal fly ash that is a waste material and a cheap source of Si and Al. Coal fly ash is a waste material that is produced during the combustion of coal to generate electricity. The elemental composition of coal fly ash consists of mostly SiO2 and Al2O3 together with other significant and trace elements. Zeolite ZSM-5 catalyst synthesised from coal fly ash by previous authors required an excessive amount of additional source of silica even though the XRD spectra still show the presence of quartz and mullite phase in the final products. These phases prevented the use of fly ash (solid) as a precursor to synthesise zeolite ZSM-5 products. However, the synthesis of high purity zeolite ZSM-5 products by extracting silica and alumina from South African fly ash and then using it with small amounts of fumed silica was investigated This aim was achieved by fusing fly ash (FA) with sodium hydroxide (NaOH) under hydrothermal condition set at 550 oC for 1 hour 30 minutes. The quartz and mullite phase observed by previous authors was digested by the fusion process. Thereafter, the treatment of fused fly ash filtrate (FFAF) with concentrated H2SO4 (98-99%), precipitated silica and removed Al that therefore increased the Si/Al ratio from 1.97 in fly ash (FA) to 9.5 in the silica extract (named fused fly ash extract). This route was designed to improve the quality of the final products and reduced the amount of fumed silica added to the synthesis mixture prior to hydrothermal synthesis. In this line of investigation, the process of adding fumed silica to the hydrothermal gel was optimised. H-FF1 with a Si/Al ratio of 9.5 was synthesised using the silica extract without the addition of fumed silica. Its XRD, SEM and relative crystallinity results proved that H-FF1 was inactive and hence was not further characterised and utilised in the conversion of methanol to hydrocarbons (MTH). Purer phase zeolite ZSM-5 products (H-FF2 and H-FF3) that were synthesised from silica extract with the addition of small amounts of fumed silica were characterised and successfully used in the methanol to hydrocarbons (MTH) reaction. The synthesised ZSM-5 products had different Si/Al ratio, different morphology, crystal size, BET surface area, and relative crystallinity as well as different trends in the MTH reaction. It was also observed that H-FF2 and H-FF3 (pure phase) solid catalyst deactivated faster than the commercial H-ZSM-5 in the MTH reaction. However, the MTH conversion over H-FF2 competed with that of the commercial H-ZSM-5 within 3 hours of time on stream (TOS) but later deactivated at a faster rate. This was caused by the large crystal size and reduced BET surface area of H-FF2 when compared to the commercial H-ZSM-5. However, H-FF2 performed better than H-FF3 on stream (MTH reaction) due to its smaller crystal size and higher BET. This study has successfully utilised a route that synthesised high purity zeolite ZSM-5 products from the South African fused fly ash extract (FFAE) with the addition of small amounts of fumed silica. The properties of the synthesised zeolite ZSM-5 products (H-FF2 and H-FF3) were similar to that of the commercial H-ZSM-5 as well as active in the MTH reaction. This promoted the utilisation of a waste material (coal fly ash) to synthesise highly siliceous zeolite ZSM-5 products that avoided the presence of mineral phases from fly ash in the final products.
Liu, X. "Gallosilicate zeolites." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377222.
Повний текст джерелаKhodabandeh, Shervin Davis Mark E. Davis Mark E. "Synthesis of alkaline-earth zeolites /." Diss., Pasadena, Calif. : California Institute of Technology, 1997. http://resolver.caltech.edu/CaltechETD:etd-01102008-150302.
Повний текст джерелаBessa, Raquel de Andrade. "Synthesis and characterization of composite magnetic zeolites using kaolin for softening water." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=17007.
Повний текст джерелаThe present work deals about the synthesis and characterization of magnetic zeolites obtained by hydrothermal route using kaolin from Brazilian Northeast as silicon and aluminum source. By means of the X-ray diffraction technique it was possible to identify zeolite LTA and zeolite P1 as major crystalline phases for each synthesis, with low intensity peaks referent to unreacted quartz present in the kaolin used, which is in accordance to the. FTIR spectra; the nanoparticles were identified as magnetite, with low intensity peaks referent to goethite. In scanning electron microscopy, however, it was not possible to morphologically identify these minor components, while the zeolites showed well defined morphologies, presenting unchanged morphology when in the composites form, but with nanoparticles dispersed over their surface, as expected. From transmission electron microscopy it was observed that the nanoparticles were of ca. 50 nm. Magnetic measurements indicated magnetite presence with superior diameter to critical diameter to superparamagnetic particles and remanent magnetization. Thermogravimetric analyses showed for the composites, lower mass loss than compared to the pure zeolites what may be associated to the improvement of its thermal stability. Granulometric distribution indicated nanoparticles agglomeration in variable sizes, while zeolites formed agglomerates of ca. 10 Âm. Water softening was accomplished by using both zeolites, with high efficiency on Ca2+ removal and similar behavior between the zeolite and its respective composite, being the best result observed for zeolite A, with efficiency of 97,95%, reaching equilibrium in the first contact minutes. The dependence on mass studies also showed that zeolite A and its composite presented the best efficiency, whereas zeolite P achieved the same removal levels using corresponding zeolite masses (45 mg). This way, the proposed method for zeolites synthesis proved to be efficient, so that the use of a magnet is capable to attract them, leading their excellent separation from the aqueous medium with its ionic exchange capacity unaffected.
O presente trabalho trata da sÃntese e caracterizaÃÃo de zeÃlitas magnÃticas obtidas por impregnaÃÃo de nanopartÃculas de magnetita a zeÃlitas A e P, sintetizadas por mÃtodo hidrotÃrmico utilizando caulim branco do Nordeste brasileiro como fonte de silÃcio e alumÃnio. Por meio da tÃcnica de difraÃÃo de raios-X foi possÃvel identificar como fases cristalinas majoritÃrias a zeÃlita LTA e P1 para cada sÃntese, com picos de baixa intensidade referentes a quartzo, resistente ao processo tÃrmico de tratamento prÃvio do caulim, bem como nos espectros de infravermelho; as nanopartÃculas foram identificadas como magnetita, havendo ainda indÃcios da presenÃa de goethita em pequena quantidade. Nas anÃlises de microscopia eletrÃnica de varredura, entretanto, nÃo foi possÃvel identificar esses componentes minoritÃrios morfologicamente; enquanto que a morfologia das zeÃlitas mostrou-se bem definida, sem alteraÃÃes apÃs a formaÃÃo dos compÃsitos, apenas com nanopartÃculas espalhadas em sua superfÃcie, como desejado. A partir da microscopia eletrÃnica de transmissÃo, pÃde-se observar melhor a variaÃÃo de tamanho das nanopartÃculas, em mÃdia de 50 nm. Medidas magnÃticas das amostras com essa propriedade indicaram a presenÃa de magnetita com diÃmetro superior ao diÃmetro crÃtico para partÃculas superparamagnÃticas e magnetizaÃÃo remanente. As anÃlises termogravimÃtricas mostraram que a adiÃÃo das nanopartÃculas Ãs zeÃlitas diminuiu sua perda de massa diante do aumento de temperatura e as anÃlises de distribuiÃÃo granulomÃtrica indicaram a aglomeraÃÃo das nanopartÃculas em tamanhos variÃveis, enquanto que as zeÃlitas formaram aglomerados de aproximadamente 10 Âm. Os ensaios de abrandamento de Ãguas mostraram alta eficiÃncia das zeÃlitas em remover Ca2+, com comportamento similar entre a zeÃlita e o seu respectivo compÃsito, encontrando para a zeÃlita A o maior percentual de remoÃÃo, de 97,95 %, atingindo equilÃbrio nos primeiros minutos de aplicaÃÃo. Os estudos de massa tambÃm mostraram a eficiÃncia da zeÃlita A e de seu compÃsito, tendo a zeÃlita P se aproximado dos mesmos nÃveis de remoÃÃo em massas referentes a 45 mg de zeÃlita. Assim, o mÃtodo proposto para sÃntese das zeÃlitas magnÃticas mostrou-se eficiente, de modo que a utilizaÃÃo de um Ãmà à capaz de atraÃ-las facilitando a separaÃÃo do meio apÃs a aplicaÃÃo em meio aquoso e sua capacidade de troca iÃnica nÃo foi afetada.
Kibby, Sarah A. M. "Applications of zeolites to organic synthesis." Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/10989.
Повний текст джерелаSeverance, Michael A. "Nanocrystalline Zeolites: Synthesis, Mechanism, and Applications." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1387817713.
Повний текст джерелаRonchi, Laura. "Synthesis of Hydrophobic Zeolites for Energetic Applications." Thesis, Mulhouse, 2017. http://www.theses.fr/2017MULH0678/document.
Повний текст джерелаZeolites are microporous crystalline solids widely used in adsorption, catalysis, ion exchange and molecular sieving. Hydrophobic pure-silica zeolites (zeosils) can be used for mechanical energy absorption and storage by high pressure intrusion-extrusion of water. Depending on the “zeosil-water” system, when the pressure is released (extrusion), the system is able to restore, dissipate or absorb the supplied mechanical energy during the compression step (intrusion) and therefore to display a spring, shock absorber or bumper behavior. Recently, it was found that the use of aqueous salt solutions could considerably improve the energetic performances of such systems by an increase of the intrusion pressure.In this work the intrusion of water and LiCl solutions was studied for different zeosils in order to understand the relationship between the structure of zeosils (pore size, pore system type and dimensionality) and the behavior or the energetic performances of “zeosil-liquid” systems. The experiments with cage-type zeosils confirmed a lower intrusion pressure in comparison with channel-type ones. The intrusion pressure strongly increases with the LiCl content for the zeosils with small pore openings, particularly, for the cage-type ones, while for larger pores this increase is less important. An influence of salt concentration on the behavior of “zeosils-liquid” systems probably due to the particular nature of highly concentrated solutions was also shown
Herreros, Bruno. "Silicoglycolates in zeolite synthesis." Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/273044.
Повний текст джерелаSchmidt, Iver. "Design of nanoporous materials for light alkane transformation." Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369114.
Повний текст джерелаNearchou, Antony. "Zeolites fit for a crown." Thesis, University of Bath, 2019. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767594.
Повний текст джерелаTaylor, Ann Elizabeth. "Microwave synthesis and occlusion reactions of zeolites." Thesis, University of Birmingham, 2007. http://etheses.bham.ac.uk//id/eprint/79/.
Повний текст джерелаShah, Rashed. "Zeolite-Modified Fischer-Tropsch Synthesis." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10738.
Повний текст джерелаGuarino, Bertholini Marita. "Innovative applications of natural zeolites." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/96581/1/Marita_Guarino%20Bertholini_Thesis.pdf.
Повний текст джерелаHealey, Adam Michael. "Synthesis and characterisation of potential high capacity ion exchange materials." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299518.
Повний текст джерелаNaydenov, Valeri. "Structured molecular sieves : synthesis, modification and characterization /." Luleå, 2003. http://epubl.luth.se/1402-1544/2003/39.
Повний текст джерелаForbes, Neil R. "Synthesis of zeolites in the presence of diethanolamine." Thesis, Imperial College London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268138.
Повний текст джерелаWilliams, Jennifer Jean. "The modelling, synthesis and mechanical properties of zeolites." Thesis, University of Exeter, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438377.
Повний текст джерелаPetushkov, Anton. "Synthesis and characterization of nanocrystalline and mesoporous zeolites." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1057.
Повний текст джерелаKuhn, Raquel Cristine. "Purificação de oligossacarideos utilizando coluna de leito fixo de zeolitas." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256546.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-07T02:51:20Z (GMT). No. of bitstreams: 1 Kuhn_RaquelCristine_M.pdf: 869149 bytes, checksum: 29e524283c358cff48f2049cd6406f50 (MD5) Previous issue date: 2006
Resumo: Os frutooligossacarídeos (FOS) são considerados ingredientes naturais de alimentos devido aos efeitos benéficos na proliferação de bifidobactérias no cólon humano, sendo classificados como prebióticos. Estudos recentes demonstram que a separação cromatográfica de monossacarídeos e misturas de dissacarídeos pode melhorar através da utilização de zeólitas Y, sendo também promissoras na separação de oligossacarídeos. Neste estudo, colunas com zeólitas foram utilizadas na separação de oligossacarídeos. A enzima produtora dos frutooligossacarídeos foi isolada de Rhodotorula sp., produzindo seletivamente GF2 (kestose), GF3 (nistose) e GF4 (frutofuranosilnistose). O rendimento de frutooligossacarídeos produzidos foi de 52% quando foi utilizada sacarose 50% como substrato. A separação dos frutooligossacarídeos foi realizada através de coluna empacotada com zeólitas Y trocadas com íons Ba2+. A eficiência de separação foi utilizada como critério para caracterizar a separação. Efeitos de temperatura (400C a 500C), quantidade de amostra injetada (1 a 3 mL), vazão (0,08 a 0,12 mL.min-1) e composição do desorvente (etanol 40 a 60%) foram analisados, através de um planejamento experimental fracionário, onde a vazão se mostrou significativa. O estudo de separação dos açúcares demonstrou que a condição mais favorável para a separação foi com duas colunas em série com etanol 60% como desorvente, temperatura de 500C, vazão de 0,08 mL.min-1 e quantidade de amostra injetada de 1 mL. Os valores de eficiência de separação foram de 0,60 para oligossacarídeos e glicose, 1,00 para oligossacarídeos e frutose, 0,22 para oligossacarídeos e sacarose, 0,43 para glicose e frutose, 0,82 para glicose e sacarose e 1,23 para frutose e sacarose
Abstract: Fructooligosaccharides (FOS) are nowadays considered natural food ingredients because of their beneficial effects in proliferating bifidobactéria in human colon; FOS are classified as prebiotics. Some recent studies show that the chromatographic separation of monosaccharides and a mixture of the disaccharides can be improved by using Y-zeolites, being promising in the separation of oligosaccharides. In this study, a column packed with zeolite was used to study the separation of oligosaccharides. The enzyme, which produces FOS from sucrose, was isolated from Rhodotorula sp., produced selectively GF2 (kestose), GF3 (nystose) and GF4 (frutofuranosyl nystose). The final yield of FOS was 52% when 50% sucrose was used as substrate. For the separation of fructooligosaccharides was used column packed with Ba2+ - exchanged Y zeolites. Efficiency of separation was used as a criterion to characterize the effectiveness of the separation. Effects of temperature (400C a 500C), amount of mixture injection (1 a 3 mL), flow rate (0,08 a 0,12 mL.min-1) and desorbent composition (ethanol 40 a 60%) were investigated, the according to a fractionary fatorial design; the flow rate was a significant factor under the response of efficiency of separation. The study of separation of sugars showed that the most favorable conditions for this separation were with utilization of two columns in series with ethanol 60% as desorbent, temperature of 500C, flow rate of 0,08mL.min-1 and amount of mixture injection of 1 mL. The values for the separation efficiency were 0,60 for oligosaccharides-glucose, 1,00 for oligosaccharides-fructose, 0,22 for oligosaccharides-sucrose, 0,43 for glucose-fructose, 0,82 for glucose-sucrose and 1,23 for fructose-sucrose
Mestrado
Mestre em Engenharia de Alimentos
Hill, Susan Jane. "The synthesis of transition metal substituted aluminophosphate molecular sieves using tetrahalometallates." Thesis, University of Wolverhampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337315.
Повний текст джерелаWarrender, Stewart James. "Structure direction in the formation of zeolitic materials." Thesis, University of St Andrews, 2007. http://hdl.handle.net/10023/376.
Повний текст джерелаNouar, Farid. "Design, Synthesis and Post-Synthetic Modifications of Functional Metal-Organic Materials." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1725.
Повний текст джерелаTamer, Nadir Hakan. "Synthesis And Characterization Of Zeolite Beta." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607433/index.pdf.
Повний текст джерела#8729
Al2O3&
#8729
x SiO2&
#8729
4.6 (TEA)2O&
#8729
444 H2O was utilized. The synthesis parameters were SiO2/Al2O3 ratio (20 &
#8804
x &
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50) and crystallization time (6 &
#8804
t &
#8804
16 days). Pure zeolite beta was crystallized from the experiments which were performed with the batch composition having SiO2/Al2O3 of 20 and 30 in 6 to 16 days period. For SiO2/Al2O3 of 20 and 30, the highest yield was obtained for 12 days. Therefore, the rest of the experiments, in which SiO2/Al2O3 was 40 and 50, were carried out keeping the synthesis time constant (12 days). Pure zeolite beta was also synthesized for SiO2/Al2O3 of 40 and 50. The highest yield and the most crystalline zeolite beta sample were obtained from the experiment performed at SiO2/Al2O3 of 50 with a synthesis time of 12 days. The morphology and crystal size of the zeolite beta samples were identified by using scanning electron microscope (SEM). It was observed that, zeolite beta samples had spheroidal morphology with the crystal size of about 0.5 &
#956
m. According to the thermogravimetric analyses (TGA), it was found that template molecules and moisture constituted nearly 18 % by weight of the zeolite beta samples. The surface area of the calcined zeolite beta sample was determined by N2 adsorption and was found to be 488 m2/g. Gravimetric sorption analyses yield that, the limiting sorption capacity of Na-Beta for methanol, ethanol, isopropanol and n-butanol at 0°
C was about the same with a value of 0.25 cm3/g. For o-xylene, m-xylene and p-xylene that value was 0.21 cm3/g, 0.22 cm3/g and 0.24 cm3/g, respectively.
Molina, Aurora De La Trinidad. "Synthesis of zeolites and their utilisation in waste treatment." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405726.
Повний текст джерелаRossin, Joseph A. "Synthesis, characterization and reactivity of transition metal containing zeolites." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/76271.
Повний текст джерелаPh. D.
Li, Yunxiang. "Modification of zeolites and synthesis of SAPO-templated carbon." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-141834.
Повний текст джерелаAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
Firth, Daniel Sean. "A manifold destiny : advancing the frontiers of the ADOR process." Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/15664.
Повний текст джерелаGilbert, Darren J. "Synthesis and processing using supercritical fluids." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388317.
Повний текст джерелаCarleen, Bradford J. "Hydrothermal Synthesis Process for the Production of Silicalite-1 Crystal Aggregate Packing Particles." Digital WPI, 2010. https://digitalcommons.wpi.edu/etd-theses/137.
Повний текст джерелаCetinturk, Gurtepe Irde. "Synthesis Of Binderless Tubular Zeolite X Macrobodies." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612789/index.pdf.
Повний текст джерелаpreparing hydrogel by mixing sodium aluminate and sodium silicate solutions, filtration of the hydrogel, paste preparation from solid phase of the hydrogel, extrusion of green tubes from paste, calcination of green tubes and crystallization of calcined tubes in filtered liquid of the hydrogel. In this study, synthesis of binderless tubular pure zeolite X macrobodies with high crystallinity was achieved. Micropore volume and BET surface area of the zeolite X tubular macrobody IÇ
S-18, which has 99.9 % crystallinity were determined as 0.178 cm3/g and 631.2 m2/g, respectively. Pure zeolite X, pure zeolite A and zeolite A, X mixtures were obtained after the crystallization of the calcined extrudates which were obtained from different hydrogel compositions. Ternary diagram which was based on the hydrogel compositions and the obtained zeolite phases was plotted.
Onder, Aylin. "Synthesis Of Zeolite Membranes In Flow System." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614815/index.pdf.
Повний текст джерелаC and 220°
C, and the corresponding system pressures were approximately 20 and 30 bars for MFI and SAPO-34, respectively. The CH4 and n-C4H10 single gas permeances were measured through MFI membranes and the performance of membranes was investigated in the separation of equimolar CH4/n-C4H10 mixtures. The best MFI membrane had a CH4 single gas permeance of 1.45x10-6 mol/m2-s-Pa and CH4/n-C4H10 ideal selectivity of 35 at 25oC. The membranes preferentially permeated n-C4H10 in the separation of mixtures. The n-C4H10/CH4 separation selectivity was 43.6 with a total permeance of approximately 0.8x10-6 mol/m2-s-Pa at 25oC. The ideal selectivities of CO2/CH4 of SAPO-34 membrane synthesized in stagnant medium were 227, and >
1000 at 220 and 200oC, respectively. Formation of amorphous structure and the additional secondary phases (impurities) were observed on SAPO-34 membranes synthesized in recirculating flow system. The results showed that it is possible to produce SAPO-34 and high quality MFI membranes by a recirculating flow system operating at elevated temperature.
Burkett, Sandra Louise Davis Mark E. "Mechanisms of structure direction in zeolite synthesis /." Diss., Pasadena, Calif. : California Institute of Technology, 1995. http://resolver.caltech.edu/CaltechETD:etd-11102005-104907.
Повний текст джерелаSandström, Linda. "Zeolite membranes for efficient synthesis of biofuels /." Luleå : Luleå university of technology, 2009. http://pure.ltu.se/ws/fbspretrieve/3283415.
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