Chromium Vi
Mostrando 1-12 de 94 artigos, teses e dissertações.
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1. Yellow Mombin (Spondias mombin L.) Seeds from Agro-Industrial Waste as a Novel Adsorbent for Removal of Hexavalent Chromium from Aqueous Solutions
The objective of this study was to develop a low-cost and eco-friendly adsorbent from agro-industrial waste for the removal of hexavalent chromium in the aqueous medium. The adsorbent (BMC) produced from yellow mombin (Spondias mombin L.) seeds was characterized by the determination of the chemical composition, thermal analysis (thermogravimetric (TG) analys
J. Braz. Chem. Soc.. Publicado em: 2021-02
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2. Optimization of Methodology for Determination of Inorganic Chromium Species in Sewage Sludge Samples by HPLC-ICP-MS/MS
This study developed a methodology for extracting and speciating CrIII and CrVI in sewage sludge by high performance liquid chromatography, inductively coupled plasma tandem mass spectrometry (HPLC-ICP-MS/MS). The optimal procedure was solid-liquid extraction in a water bath with stirring at 50 °C for 16 h and 50 mmol L−1 ethylenediaminetetraacetic acid (
J. Braz. Chem. Soc.. Publicado em: 2020-12
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3. Preparation and application of Zero Valent Iron immobilized in Activated Carbon for removal of hexavalent Chromium from synthetic effluent
RESUMO Diferentemente dos contaminantes orgânicos, os metais pesados não são biodegradáveis e tendem a se acumular nos organismos vivos e também são reconhecidos por serem tóxicos ou carcinogênicos. A utilização de nanopartículas de ferro zero valente (nFVZ) é relatada como uma técnica alternativa e de elevado potencial para remediação in situ
Rev. Ambient. Água. Publicado em: 03/10/2019
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4. STUDY OF THE CHROMIUM(VI) REMOVAL FROM AQUEOUS SYSTEMS BY COBALT NANOPARTICLES
The cobalt nanoparticles (NPs-Co) were synthesized and applied in the removal of Cr(VI). The obtained nanomaterials presented magnetic properties and were characterized by the techniques of Transmission Electron Microscopy and X-ray diffraction. The NPs-Co, with a diameter of less than 50 nm, had a composition based on metallic cobalt and cobalt oxide. The N
Quím. Nova. Publicado em: 18/07/2019
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5. Oxidative Stress, Chromium-Resistance and Uptake by Fungi: Isolated from Industrial Wastewater
ABSTRACT Trichosporon asahii and Rhodotorula mucilaginosa isolated from wastewater effluents were identified as chromium-resistant yeasts. Cr(VI) concentrations at 8 mM and 6 mM were inhibitory for R. mucilaginosa and T. asahii. Remarkably elevated GSH (69.88 ± 10.01) and GSSG (11.24 ± 0.96) was observed under metal stress in T. asahii as compared to R. mu
Braz. arch. biol. technol.. Publicado em: 14/06/2018
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6. Interference film grown on stainless steel by pulsed current process using chromium free vanadate solution
ABSTRACT Deposition of interference film is an alternative way for the formation of colored protective layers on the surface of stainless steels for decorative applications. The process involves growth of a chromium oxide film by electrochemical methods using in general sulphochromic solutions. However, it is well known that chromic acid contains Cr(VI), whi
Matéria (Rio J.). Publicado em: 05/03/2018
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7. Agronomic and environmental implications of using a By-Product of the Intermediate Tanning Processes as Nitrogen Fertilizer
ABSTRACT Nitrogen (N) is an important nutrient for agriculture, and Brazil is heavily dependent on N imports. A by-product of the intermediate processes of tanning (BPIPT) may be used as an N fertilizer which will reduce this dependency, but its chromium (Cr) content is a matter of concern. This work assessed Cr (III, VI) and N (total, inorganic) contents in
Sci. agric. (Piracicaba, Braz.). Publicado em: 2017-06
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8. Speciation of Chromium in Water Samples after Dispersive Liquid-Liquid Microextraction, and Detection by Means of High-Resolution Continuum Source Atomic Absorption Spectrometry
A newly analytical method has been developed to determine total chromium and speciation of this element in water samples through dispersive liquid-liquid microextraction combined with a high-resolution continuum source flame atomic absorption spectrometry. The most significant variables affecting complexation and extraction were optimized by using response s
J. Braz. Chem. Soc.. Publicado em: 2017-02
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9. IN VITRO Cr(VI) SPECIATION IN SYNTHETIC SALIVA AFTER RELEASING FROM ORTHODONTIC BRACKETS USING SILICA-APTES SEPARATION AND GF AAS DETERMINATION
A method for Cr(VI) speciation in synthetic saliva after releasing from orthodontic brackets, using silica nanoparticles organofunctionalized with (3-aminopropyl)triethoxysilane (APTES) for Cr(III)/Cr(VI) separation and GF AAS determination is proposed. Under the optimized conditions, Cr(VI) speciation was performed using 150 mg of silica organofunctionalize
Quím. Nova. Publicado em: 2016-09
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10. Kinetic Analysis of the Decomposition of the KFe3(SO4)2-x(CrO4)x(OH)6 Jarosite Solid Solution in Ca(OH)2 Medium
The decomposition of the solid solution of potassium jarosite with chromium(VI) in Ca(OH)2 media was studied in the present work. According to experimental results, the incorporation of CrO42- into the crystal structure of jarosite resulted in a solid solution with the following approximate formula: [K0.86(H3O)0.14]Fe2.67[(SO4)1.23(CrO4)0.77][(OH)5.01(H2O)0.
J. Braz. Chem. Soc.. Publicado em: 2016-06
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11. Removal of Chromium(VI) from Industrial Effluents Through Supported Liquid Membrane Using Trioctylphosphine Oxide as a Carrier
The present study describes extraction of chromium(VI) through supported liquid membrane (SLM), Celgard 2400, which was impregnated with trioctylphosphine oxide (TOPO) dissolved in toluene. The stripping phase was comprised of diphenylcarbazide (DPC) in sulfuric acid (H2SO4) whereas the feed phase consists of potassium dichromate (K2Cr2O7) and hydrogen perox
J. Braz. Chem. Soc.. Publicado em: 2016-01
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12. Magnetic Nanoparticles Coated with Ionic Liquid as a Sorbent for Solid Phase Extraction of Chromium(VI) Prior to Its Determination by Electrothermal Atomic Absorption Spectrometry
A simple, sensitive and reliable method for the separation, preconcentration and determination of ultra trace amounts of chromium species has been developed. Chromium(VI) in aqueous sample was reacted with 9-phenyl-2,3,7-trihydroxy-6-fluorone to produce a chelate at pH of 5.0 and extracted onto the magnetic nanoparticles coated with the ionic liquid 1-hexade
J. Braz. Chem. Soc.. Publicado em: 2016-01