Metals
Mostrando 25-36 de 2170 artigos, teses e dissertações.
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25. Telepsychiatry in Brazil during the COVID-19 pandemic: Did we exchange a walk-on part in a war for a lead role in a cage?
Abstract Wheat and rice constitute important cereal crops and any contamination may pose potential adverse impacts on human health. The study was conducted to determine eight trace metals, i.e. cadmium (Cd), copper (Cu), cobalt (Co), chromium (Cr), zinc (Zn), lead (Pb), nickel(Ni), manganese (Mn), in wheat, rice and soil samples collected from different citi
J. bras. psiquiatr.. Publicado em: 2020-12
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26. Zeolite-SPION Nanocomposite for Ammonium and Heavy Metals Removal from Wastewater
Minimizing the emission of industrial effluents and realizing the recovery/extraction of key elements such as the rare earths from low concentration solutions, or during water decontamination processes, are some of the biggest challenges of modern society. Accordingly, the preparation and characterization of a low cost recyclable and reusable superparamagnet
J. Braz. Chem. Soc.. Publicado em: 2020-11
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27. Electroanalytical Method for Determination of Trace Metals in Struvite Using Electrochemically Treated Screen-Printed Gold Electrodes
We present an electroanalytical method using square-wave anodic stripping voltammetry on electrochemically-treated screen-printed gold electrodes to the simultaneous determination of lead(II), copper(II) and mercury(II) in struvite (natural fertilizer produced from urine). Electrochemical treatment via cyclic voltammetry of the working electrodes increased s
J. Braz. Chem. Soc.. Publicado em: 2020-09
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28. A review of common parameters and descriptors used in studies of the impacts of heavy metal pollution on marine macroalgae: identification of knowledge gaps and future needs
ABSTRACT This study presents a systematic review to assess the main similarities and gaps in efforts to evaluate the impacts of heavy metals on benthic marine seaweeds. A total of 91 studies were compiled, the main parameters (abiotic, biological, ecotoxicological, and heavy metals) and descriptors of which were evaluated by quantitative and qualitative ana
Acta Bot. Bras.. Publicado em: 2020-09
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29. Mestrado Profissional em Climatologia e Aplicações nos Países da CPLP e áfrica
AuPd nanoparticles have gained substantial attention due to their application in selective oxidation of alcohols. However, due to the radical nature of the oxidation of benzyl alcohol, under specific conditions, even without a catalyst, the reaction occurs and affects the selectivity of the system. Therefore, we aimed to develop a catalyst that enables the c
Rev. bras. meteorol.. Publicado em: 2020-09
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30. Aquamarine from Massangana batholith, Rondônia State: mineral chemistry and fluid inclusion data
Abstract Beryl is usually found in granite-pegmatite systems. The addition of chromophore elements (V, Cr, Mn, Fe) into the crystalline structure favors color changes in beryl and thus generates some of the world’s expensive gems such as emerald, morganite, heliodor and aquamarine. The Massangana polyphasic batholith is a well-known cassiterite, wolframite
REM, Int. Eng. J.. Publicado em: 2020-09
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31. Drawing Electrochemical Sensors Using a 3D Printing Pen
This communication demonstrates that a 3D printing pen, commercially-available as a toy for kids, can be used to draw thermoplastic electrochemical sensors using conductive filaments over any desirable format and substrate. A polylactic acid filament containing graphene or carbon black was passed through the 3D pen that works as a handheld 3D printer (fused
J. Braz. Chem. Soc.. Publicado em: 2020-09
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32. Accessing Basic Sites on Modified CoFe2O4 Nanoparticles: Addressing the Selective Oxidation of Benzyl Alcohol and Unraveling the Au:Pd Ratio Effects by XPS
AuPd nanoparticles have gained substantial attention due to their application in selective oxidation of alcohols. However, due to the radical nature of the oxidation of benzyl alcohol, under specific conditions, even without a catalyst, the reaction occurs and affects the selectivity of the system. Therefore, we aimed to develop a catalyst that enables the c
J. Braz. Chem. Soc.. Publicado em: 2020-09
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33. SYNTHESIS OF MATERIALS PRODUCED FROM SPENT BATTERIES WITH ENVIRONMENTAL APPLICATION
In this work, alkaline and nickel-metal hydride spent batteries were used as precursors of metals for the synthesis of polymetallic materials. These materials were synthesized via chemical reduction. Materials produced from nickel-metal hydride spent batteries (PM-NiMH) have a nanometric size, whereas the alkaline spent batteries (PM-Alk) have a micrometric
Quím. Nova. Publicado em: 2020-09
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34. APRESENTAÇÃO - História Antiga: Diferentes Perspectivas
Biodiesel is a suitable alternative to replace the petro-diesel. The biodiesel is formed by unsaturated esters easily degraded by interferences of oxygen, temperature, contact with metals or contaminants. The aim of this research was to investigate the biodiesel degradation process via 1H nuclear magnetic resonance (NMR) spectroscopy, observing the olefinic,
Rev. Bras. Hist.. Publicado em: 2020-08
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35. Evaluation of the Oxidation Degradation Process of Biodiesel via 1H NMR Spectroscopy
Biodiesel is a suitable alternative to replace the petro-diesel. The biodiesel is formed by unsaturated esters easily degraded by interferences of oxygen, temperature, contact with metals or contaminants. The aim of this research was to investigate the biodiesel degradation process via 1H nuclear magnetic resonance (NMR) spectroscopy, observing the olefinic,
J. Braz. Chem. Soc.. Publicado em: 2020-08
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36. 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