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Previous issue date: 2018-01-31 / Argilas s?o mat?rias naturais, terrosos e amplamente dispon?veis na natureza. T?m em sua composi??o os argilominerais e diversas impurezas. Essas impurezas podem interferir em suas aplica??es e o uso de argilomineral sint?tico surge como uma solu??o. A fim de estudar as diferen?as entre os materiais sint?ticos e naturais, o argilomineral montmorillonita foi sintetizado em condi??es hidrot?rmicas, press?o autog?nica, meio ?cido e fluor?drico. Tanto a argila sint?tica quanto argila natural foram caracterizados por meio de difra??o de raios X (DRX), an?lise termogravim?trica (TGA), espectroscopia na regi?o do infravermelho (FTIR), resson?ncia magn?tica nuclear de 27Al (27Al RMN), adsor??o e dessor??o de N2, microscopia eletr?nica de varredura (MEV) e energia dispersiva de raios X (EDS). A argila sint?tica apresentou um difratograma de raios X com reflex?es caracter?sticas da montmorillonita, tal como a argila natural, com exce??o da presen?a de quartzo na composi??o mineral?gica desta ?ltima. Por meio das an?lises realizadas, uma maior quantidade de alum?nio foi identificada para a argila sint?tica, assim como um car?ter mais meso-macroporoso e pureza composicional, ao comparar com a argila natural. A pilariza??o das argilas foi realizada partindo de duas fontes distintas de ?ons de Keggin (preparada em laborat?rio e solu??o de clorohidr?xido de alum?nio), uma comercial e outra produzida em laborat?rio. Os materiais resultantes foram caracterizados por DRX, TGA, FTIR, 27Al RMN e adsor??o e dessor??o de N2. Os materiais pilarizados sint?ticos apresentaram uma estrutura desorganizada, por?m pilarizada, tal como constatado por meio dos difratogramas de raios e an?lise textural. A argila natural pilarizou, tamb?m, com ambas as fontes, e apresentou caracter?sticas t?picas dos materiais pilarizados. O uso de clorohidr?xido de alum?nio (ACH) como fonte de ?ons de Keggin gerou materiais com maior quantidade de esp?cies de alum?nio no espa?o interlamelar, resultando em materiais com menor volume de microporos. As ?reas espec?ficas dos materiais naturais pilarizados foram superiores as calculadas para os an?logos oriundos da argila sint?tica, devido a uma maior contribui??o da microporosidade criada com o processo de pilariza??o. / Clays are natural, earthy and widely available in nature. They have in their composition the clay minerals and various impurities. These impurities can interfere in their applications and the use of synthetic clay appears as a solution. In order to study the differences between synthetic and natural materials, the montmorillonite claymineral was synthesized under hydrothermal conditions, autogenic pressure, acidic and hydrofluoric medium. Both synthetic and natural clays were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), 27Al nuclear magnetic resonance (27Al NMR), adsorption and desorption of N2, scanning electron microscopy (SEM) and energy dispersive (EDS). The synthetic clay presented an X-ray diffraction pattern with characteristic reflections of montmorillonite, like natural clay, with the exception of the presence of quartz in the mineralogical composition of the latter. By means of the analyzes, a greater amount of aluminum was identified for the synthetic clay, as well as a more meso-macroporosity character and compositional purity, when compared with the natural clay. The pillarization of the clays was done starting from two distinct sources of Keggin ions (as made in laboratory and aluminum chlorohydrol solution), one commercial and the other produced in the laboratory. The resulting materials were characterized by XRD, TGA, FTIR, 27Al NMR and adsorption and desorption of N2. The synthetic pillared materials presented a disorganized, but pillared structure, as verified by means of X-ray diffraction and textural analysis. The natural clay also pillared with both sources presented characteristics typical of the pillared materials. The use of aluminum chlorohydrol (ACH) as a source of Keggin ions generated materials with higher amounts of aluminum species in the interlamellar space, resulting in materials with a lower volume of micropores. The specific areas of the natural pillared materials were higher than those calculated for synthetic pillared clays due to a greater contribution of the microporosity created with the pillarization process.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/24825 |
| Date | 31 January 2018 |
| Creators | Nascimento, Joe V?tor Alves do |
| Contributors | 50942611004, Gondim, Amanda Duarte, 03014598437, Penha, F?bio Garcia, 68001851915, Bertolino, Luiz Carlos, 04936904848, Pergher, Sibele Berenice Castella |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM QU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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