Zeolites
Mostrando 1-12 de 127 artigos, teses e dissertações.
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1. K2O SUPORTADO EM ZEÓLITA NATURAL: SÍNTESE, CARACTERIZAÇÃO E APLICAÇÃO PRODUÇÃO DE BIODIESEL A PARTIR DO ÓLEO DE GIRASSOL
Biodiesel is a renewable fuel, a substitute for fossil diesel, which is important for reducing GHG in Brazil. Therefore, this work aims to synthesize and characterize the catalyst using the support of natural zeolite impregnated with K2O and apply it in the production of biodiesel through the transesterification reaction. Through the analysis of characteriza
Química Nova. Publicado em: 2022
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2. Optimization and Study of the Response Surface of Properties for the Synthesis of ZSM-5 Zeolites with Hierarchical Pore Structure Obtained by Desilication
Hierarchical ZSM-5 zeolites were prepared by alkali treatment (desilication) at two temperatures, two reaction times, and two NaOH concentrations. A 23 factorial design was used to study the effect of these variables on the crystallinity, microporosity, and mesoporosity of the zeolite due to the desilication treatment. The factorial design analysis showed th
J. Braz. Chem. Soc.. Publicado em: 2021-06
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3. Porosity of CHA Zeolite Driving the Formation of Polyaromatic Coke Species in the Methanol to Olefins Reaction
The pore size of the chabazite structure is exceptionally suitable for the methanol to olefins (MTO) reaction. The reaction has an induction period required for the formation of a hydrocarbon pool (HP), usually composed of aromatic compounds of different sizes. HP is alkylated by methanol and afterward cracked, leading to the formation of olefins. Despite th
J. Braz. Chem. Soc.. Publicado em: 2021-05
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4. Reordering of Depolymerized Silicates as Adsorbents for Large Nitrogen Compounds
The adsorption capacities of two synthesized zeolites (crystalline ZSM-5 and semi-crystalline faujasite Y) for a mixture of indole, quinoline and carbazole were studied. The different samples obtained show different crystalline degree, mesoporosity and Si/Al ratios. The synthesis procedure is based on the simultaneous depolymerization of a mixture of high su
J. Braz. Chem. Soc.. Publicado em: 2021-01
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5. Development of Geopolymers for Catalyst Support Applications
A geopolymer with high specific surface area was synthesized from metakaolin, amorphous silica and KOH, in the absence of foaming or saponification agents. The mixture modelling technique was selected for this study among the Design of Experiments tools, using surface area and total pores volume as response variables. The Si/K = 2.46 and Si/Al = 1.37 ratios
Mat. Res.. Publicado em: 25/11/2019
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6. Catalytic Transformation Conditions of Ethanol on Dealuminated BEA Zeolites
Catalysis is an important tool in obtaining a range of derivative products from renewable sources, such as ethanol. Solid-state dealumination using ammonium hexafluorosilicate on the BEA zeolite under the treatment at temperature of 190 °C, 70 mol% dealumination in the presence of humidity and washing with buffer solution at 25 °C generated larger pores. T
J. Braz. Chem. Soc.. Publicado em: 21/10/2019
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7. Synthesis of high-silica ZSM-5 with seeds in the presence of ethanol and amine
Resumo A possibilidade de cristalização da ZSM-5 com alta razão Si/Al foi avaliada através do uso combinado de sementes de cristalização e compostos orgânicos que não são direcionadores convencionais da ZSM-5 (etanol, metilamina, etilamina, propilamina, butilamina, isopropilamina e dietilamina) a fim de encontrar uma rota de síntese menos tóxica e
Cerâmica. Publicado em: 15/08/2019
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8. Application of SnO2 Nanoparticles and Zeolites in Coal Mine Methane Sensors
We evaluated solid-state sensors (MOS) manufactured using nanostructured tin oxide (SnO2) obtained by different synthesis methods for selectivity, response and repeatability at different operating temperatures and methane concentrations. In addition, Zeolite 13X pellets were placed in front of the sensors to improve CH4 selectivity in the presence of CO2. Th
Mat. Res.. Publicado em: 27/05/2019
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9. Desilication of ZSM-5 and ZSM-12 Zeolites with Different Crystal Sizes: Effect on Acidity and Mesoporous Initiation
In the present work, the desilication of the H-ZSM-5 and H-ZSM-12 zeolites with Si/AL ratios of 28 and 56 and crystal sizes of around 200 and 600 nm, respectively, was performed. Through electron transmission microscopy analysis, it was possible to verify the influence of aluminium gradients on smaller crystals in addition to the exact moment at which the fo
Mat. Res.. Publicado em: 11/02/2019
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10. Selection between LTA or FAU phases by manipulating the synthesis gel composition, crystallization time and temperature
Resumo Zeólitas LTA e FAU foram sintetizadas com brometo de cetiltrimetilamônio (CTAB) visando avaliar os efeitos das razões Si/Al, Na/Al e H2O/Al, do tempo e da temperatura no rendimento de cada estrutura. A significância de cada variável foi determinada através de planejamentos experimentais, cujas variáveis resposta foram as áreas de picos de difr
Cerâmica. Publicado em: 2019-01
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11. Generación de mesoporosidad en zeolitas ZSM-11, BETA e Y por tratamiento alcalino
ABSTRACT Zeolites, Y, ZSM-11 and BETA, widely used in refineries and petrochemical processes, fine chemistry and environmental processes were subjected to an alkaline treatment of desilication, in order to generate mesoporosity in the structure. The process used consisted of treating samples with an aqueous solution of NaOH at 65 ° C for 30 minutes. An exch
Matéria (Rio J.). Publicado em: 19/07/2018
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12. Síntesis y caracterización de fotocatalizadores de hierro soportado sobre zeolitas microporosas
ABSTRACT ZSM11 and BETA zeolitic materials were synthesized by the hydrothermal method and were further impregnated with a 6 wt% of iron and characterized by different physicochemical techniques in order to be employed in the photocatalytic degradation of methyl orange (MO). Matrices structures and crystallinity were verified by X Ray Diffraction (XRD) and F
Matéria (Rio J.). Publicado em: 19/07/2018