X Ray Spectroscopy
Mostrando 1-12 de 1235 artigos, teses e dissertações.
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1. Catalysts Derived from Thermal Treatments of Hydrocalumite-Type Compounds: Synthesis and Application in Transesterification Reactions
Catalyst performance is a relevant factor in biodiesel production because it can affect the efficiency of the process. This work provides a study of the performance of heterogeneous catalysts for biodiesel production derived from thermal-treated hydrocalumite-type compounds. This work aimed to synthesize and characterize hydrocalumite-type compounds intercal
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Bimetallic Au-Pd/α-MoO3 Catalyst with High Oxygen Vacancies for Selective Oxidation of Cinnamyl Alcohol
Supported Au-Pd nanoparticles (NPs) have been extensively studied in alcohol oxidation reactions. However, few studies use reducible metal oxides as support, which can activate oxygen molecules and boost the selectivity of the reaction. In this work, Au-Pd NPs were supported on α-MoO3 and evaluated in the selective oxidation of cinnamyl alcohol without solv
Journal of the Brazilian Chemical Society. Publicado em: 2023
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3. Study of rhombohedral tricalcium phosphate in hexagonal crystal structure family on the sample prepared by the sol-gel route and the effect of calcination temperature
Abstract The effect of the calcination temperature at 800 and 1000 °C on the stable formation of the tricalcium phosphate with rhombohedral structure in the system of the hexagonal crystal family was determined, while its precursor was made from limestone obtained from nature in the Lumajang district, Indonesia. The rhombohedral tricalcium phosphate samples
Cerâmica. Publicado em: 2023
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4. Carbon Dots from Pilosocereus gounellei for Fluorimetric Determination of Tannin in Tea Using a Flow-Batch System
In this study, xiquexique (Pilosocereus gounellei) native endemic cactus from the Brazilian semiarid was used for the first time as a natural carbon source (“green precursor”) for the synthesis of highly fluorescent carbon dots (CDs). These CDs were successfully used to develop a fast, low-cost, eco-friendly fluorescence method for the determination of t
Journal of the Brazilian Chemical Society. Publicado em: 2023
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5. Synthesis of delafossite CuCrO2 via solution combustion method and its acid functionalization for biodiesel production
Abstract CuCrO2 was synthesized by solution combustion synthesis (SCS) and applied as a heterogeneous catalyst to produce soybean biodiesel. The combustion reaction was carried out using urea as a fuel, and copper (II) and chromium (III) nitrates as precursors. After the powders’ obtention, these were calcined and functionalized in an acidic medium. The po
Cerâmica. Publicado em: 2023
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6. A química analítica aplicada aos estudos de pigmentos rupestres: uma revisão
Instrumental advances have been employed in the study of archeological remains such as prehistoric rupestrians paintings with the objective of chemically characterizing them in order to reconstruct the cultural technologies of a prehistoric human group and/or to support conservation science studies. The analytical techniques most commonly used in archaeometr
Química Nova. Publicado em: 2022
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7. Enhancement of Visible Light-Responsive Photocatalytic Efficiency by Using a Laccaic Acid-Modified Titanium Dioxide Photocatalyst
In this study, a laccaic acid-modified TiO2 photocatalyst (Lac-TiO2) was prepared via an impregnation method with 0.50, 1.00, 2.50, and 5.00 wt.% laccaic acid. The products’ physical properties were examined through X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoemission spectroscopy (XPS), UV-Vis diffused
Journal of the Brazilian Chemical Society. Publicado em: 2022
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8. The influence of separately and combined bentonite and kaolinite as binders for pelletization of NaA zeolite from coal fly ash
Abstract Pelletization of zeolitic materials is required to facilitate their practical industrial and commercial applications. Zeolite-NaA was synthesized from fly ash by the fusion method and shaped into spherical granules. Bentonite, kaolinite, and a combination of bentonite with kaolinite were tested as binders with different contents from 5 to 10 wt%. Th
Cerâmica. Publicado em: 2022
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9. Preparation and performance of magnetic zirconium-iron oxide nanoparticles loaded on palygorskite in the adsorption of phosphate from water
Magnetic zirconium-iron oxide nanoparticles loaded on palygorskite as a low-cost adsorbent was produced by one-step co precipitation technique and its properties for phosphate adsorption were overall investigated. The Brunauer Emmett Teller (BET) specific surface area analysis, scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), Fourier tr
Química Nova. Publicado em: 2022
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10. Study of nanocomposites with carbon nanotubes and their tendency for carbon organization
Abstract The carbon derived from the thermal treatment of modified phenolic resins (PR) tends to organize into graphitic lamellae or turbostratic carbon and is commonly considered non-graphitizable. In this study, nanocomposites were synthesized with modified phenolic resin (Novolac) used as the matrix and oxidized multi-walled carbon nanotubes (NTox) in amo
Cerâmica. Publicado em: 2022
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11. Thermostimulated crystal structure transformation of the polymineral clay submicron particles
Abstract Changes in the structure of phyllosilicate microparticles of submicron fractions of polymineral clay with an average size of 290 nm, as well as changes in the positions of impurity ions of transition metals in the crystal lattice, were studied by X-ray diffraction analysis, Fourier transform infrared spectroscopy, and high-resolution electron parama
Cerâmica. Publicado em: 2022
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12. EFFECT OF REACTION CONDITIONS ON PARTICLE SIZE OF ZNO NANOPARTICLES VIA CONTROLLED PRECIPITATION METHOD AND IN-VITRO ANTIBACTERIAL CAPACITY
High-yield ZnO spheroidal nanoparticles with an average diameter around 23 nm (≈ 25% frequency) and 30 nm (≈ 28% frequency) were obtained by controlled semicontinuous precipitation at low temperatures. This synthesis was obtained from hydrozincite (Zn5(CO3)2(OH)6) as primary nanoparticles. The Zn5(CO3)2(OH)6 nanoparticles were synthesized by hydrolysis o
Química Nova. Publicado em: 2022