Leaching
Mostrando 13-24 de 435 artigos, teses e dissertações.
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13. Maximization of the use of casting sand residue in the production of fired ceramic bricks
Abstract In this study, a red ceramic was developed with the addition of sand residue from deburring and finishing processing of cast iron molds, replacing a variable fraction of the clay. The formulated masses were shaped by pressing and firing at different temperatures (850, 900 and 1000 ºC) at a heating rate of 180 ºC/h and 2-hour level. The bodies were
REM, Int. Eng. J.. Publicado em: 2020-09
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14. DETERMINATION OF THE PESTICIDES IN WATER USED IN THE CULTURE AND PROCESSING OF POTATOES
The contamination of water bodies by pesticide residues through direct flow, leaching and other methods has motivated the development of analytical methods for the determination of these compounds in water. A vortex-assisted liquid-liquid microextraction method followed by gas chromatography coupled to mass spectrometry for the determination of anilazine, li
Quím. Nova. Publicado em: 2020-09
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15. PROCESSING OF A METAL CONCENTRATE FROM GROUND WASTE PRINTED CIRCUIT BOARDS IN ACIDIC MEDIA USING HYDROGEN PEROXIDE AS OXIDANT
The recovery of precious and base metals of a metal concentrate from ground waste printed circuit boards (PCBs) is described in detail. Samples were treated with NaOHaq. to remove the soldering mask. Experiments were performed in acidic medium (HF, H2SO4, CH3COOH or H3PO4) using H2O2 as oxidant. Base metals were leached in high yields (>99 wt.%) at ~40 ºC a
Quím. Nova. Publicado em: 20/07/2020
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16. Effects of addition of engineered ZnO nanoparticles on the stability of colloidal suspensions containing TiO2 interacting with sandy soil
Abstract The stability of colloidal suspensions of engineered nanoparticles in the environment is of great interest for the risk assessment and treatment of hazardous materials. The relevance of this study is due to the evidence that engineered nanoparticles have been produced and used in commercial products in large scale, especially ZnO and TiO2, which are
REM, Int. Eng. J.. Publicado em: 2020-06
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17. Minieditorial: Risco de FA após Ablação de Flutter Dependente de Istmo Cavo-Tricuspídeo: Vale a Pena Fazer a Ablação da FA Simultaneamente?
Considering the size of the Amazon region and the need for studies to establish soil trace metal concentrations in natural environments, the objective of this work was to evaluate heavy metal contents in a toposequence of an Amazon State microbasin. Soil samples were collected in three native forest topographic positions. Samples were opened for analysis by
Arq. Bras. Cardiol.. Publicado em: 2020-05
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18. VALORES DE REFERÊNCIA DA CONCENTRAÇÃO DE METAIS PESADOS EM SOLOS NA AMAZÔNIA CENTRAL
Considering the size of the Amazon region and the need for studies to establish soil trace metal concentrations in natural environments, the objective of this work was to evaluate heavy metal contents in a toposequence of an Amazon State microbasin. Soil samples were collected in three native forest topographic positions. Samples were opened for analysis by
Quím. Nova. Publicado em: 2020-05
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19. Potential Slow Release Fertilizers Based on K2MgSiO4 Obtained from Serpentinite
In this work, a potassium magnesium silicate mineral based on phase K2MgSiO4 was prepared from serpentinite rock and studied as a potential K and Mg slow-release fertilizer. The material was prepared by impregnation of serpentinite/KOH and calcination at 700 °C to produce K2MgSiO4 phase, olivine and forsterite. The release patterns of K and Mg in the stirre
J. Braz. Chem. Soc.. Publicado em: 2020-04
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20. Residue-Based CaO Heterogeneous Catalysts from Crab and Mollusk Shells for FAME Production Via Transesterification
The production of fatty acid methyl esther (FAME) via transesterification was studied, assessing the influence of CaO heterogeneous catalysts obtained from four different fishery residues: sururu, crab, clam and mussel. Characterization and properties of the residues were obtained via thermogravimetric analysis, X-ray diffraction, X-ray fluorescence, Fourier
J. Braz. Chem. Soc.. Publicado em: 2020-04
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21. Evaluation of α- and β-Endosulfan Residues in Teas and Yerba Mate Infusions by Bar Adsorptive Microextraction and Large Volume Injection-Gas Chromatography Mass Spectrometry
Tea and yerba mate are traditional beverages prepared through the infusion of leaves of Camellia sinensis and Ilex paraguariensis, respectively. During this process, the leaching of pesticides onto the beverage, such as endosulfan, may occur. In this study, a bar adsorptive microextraction (BAµE) method prior to large gas chromatography mass spectrometry an
J. Braz. Chem. Soc.. Publicado em: 2020-03
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22. SIMULATION AND EXPERIMENTAL INVESTIGATION OF POWER CONSUMPTION, GAS DISPERSION AND MASS TRANSFER COEFFICIENT IN A MULTI-PHASE STIRRED BIOREACTOR
Abstract Bio-oxidation leaching of refractory gold concentrate was carried out in a typical gas-liquid-solid three-phase stirred bioreactor. The bacteria, which adhered to solid particle surfaces and spread over the liquid phase, require sufficient oxygen and nutrient of carbon and nitrogen, and then the mass transfer rate should be considered. However, the
Braz. J. Chem. Eng.. Publicado em: 13/01/2020
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23. RE-ESTERIFICATION OF MACAUBA ACID OIL USING GLYCEROL FOR ACIDITY REDUCTION AND BIODIESEL PRODUCTION
Abstract Biodiesel production using acid oils is an important alternative for biofuel cost reduction. However, it is a huge challenge for homogeneous transesterification, the main industrial route commonly used. This paper presents macauba oil with high acidity, 43.90 w/w%, as a potential raw material for biodiesel production. The acidity was reduced to 0.8
Braz. J. Chem. Eng.. Publicado em: 09/12/2019
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24. Potassium leaching test in evaluation of popcorn seed vigor
Resumo: A busca por testes que ofereçam rapidez e informações seguras sobre o potencial fisiológico das sementes, torna-se de fundamental importância para programas de controle de qualidade. O objetivo deste trabalho foi avaliar a eficiência do teste de lixiviação de potássio na identificação de diferentes níveis de vigor de lotes de sementes de
J. Seed Sci.. Publicado em: 05/12/2019