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hexavalent chromium reduction

Reducing Hexavalent Chromium to Trivalent Chromium

Aqueous hexavalent chromium, Cr(VI), is rapidly reduced to trivalent chromium, Cr(III), by exposure to (polystyrylmethyl)trimethylammonium borohydride and with Amberlite-supported mild bases in a heterogeneous environment. Post-reaction removal of the insoluble reagents leaves no remediation-based chemical footprint in the source water. Time dependence with stirred and static conditions is

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US3896209A Reduction of hexavalent chromium Google

Under acidic conditions the hexavalent chromium present in aqueous solutions is chemically reduced to trivalent chromium with hydrogen peroxide. This process is improved if the pH of the aqueous...

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Reduction of hexavalent chromium and degradation of

This study investigates the photocatalytic reduction of hexavalent chromium (Cr(VI)) and degradation of tetracycline (TC) via visible-light-active In-doped Mn 2 O 3 photocatalysis. Mn 2 O 3 photocatalysts loaded with different In doses are prepared using a simple hydrothermal method, and the results indicate the formation of Mn 2 O 3 nanorod -like structures with good crystallinity.

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Reduction of Hexavalent Chromium by H2O2 in Acidic

Reduction of hexavalent chromium by ascorbic acid in aqueous solutions. Chemosphere 2004, 57 (7),609-613. https://doi.org/10.1016/jemosphere.2004.07.031; Tiangui Wang, Zuohu Li. High-temperature reduction of chromium (VI) in solid alkali.

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Reduction of Hexavalent Chromium and Detection of

13/02/2018· Hexavalent chromium reduction was mainly associated with the soluble fraction of the cell evaluated with crude cell-free extracts. A protein of molecular weight around 25 kDa was detected on SDS-PAGE gel depending on the concentration of hexavalent chromium in the medium (0, 100 and 500 mg/L). In silico analysis in this contribution, revealed the presence of the chromate reductase gene

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Hexavalent Chromium Wastewater Treatment Industrial

24/09/2020· Hexavalent chromium reduction is commonly accomplished using chemical reduction. Hexavalent chromium is reduced to trivalent chromium at acid pH using chemical reduction agents. Sodium bisulfide, sodium metabisulfide, and ferrous sulfate are among the common reduction agents used for small plants.

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US20090014094A1 Methods for Reducing Hexavalent

The trivalent chromate conversion coating includes hexavalent chromium and the reducing solution including a reducing agent, which reduces the hexavalent chromium so as to reduce

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Hexavalent Chromium Overview Occupational Safety

Hexavalent chromium [Cr(VI)] is one of the valence states (+6) of the element chromium. It is usually produced by an industrial process. Cr(VI) is known to cause cancer. In addition, it targets the respiratory system, kidneys, liver, skin and eyes. Chromium metal is added to alloy steel to increase hardenability and corrosion resistance. A major source of worker exposure to Cr(VI) occurs during "hot work" such

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Chrome hexavalent — Wikipédia

Le chrome hexavalent ou chrome est le 6e état d'oxydation du chrome. Les produits qui en contiennent sont le plus souvent extrêmement toxiques. Le chrome se trouve dans cet état d’oxydation dans de nombreux composés, tels que le trioxyde de chrome, le dichromate de sodium, le dichromate de potassium et le chromate de strontium, qui sont utilisés dans des procédés industriels: tannage du

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Reduction of hexavalent chromium: photocatalysis and

Hexavalent chromium present in wastewater discharge of galvanic industries is toxic to most microorganisms and potentially harmful to human health. This work examines the photochemical reduction of Cr(VI) with ethanol under ultraviolet (UV) and visible radiation, and photocatalytic reduction of Cr(VI) with TiO 2 in the presence of ethanol under UV radiation.

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Microwave synthesis of ZnIn2S4/WS2 composites for

Microwave synthesis of ZnIn 2 S 4 /WS 2 composites for photocatalytic hydrogen production and hexavalent chromium reduction † Watcharapong Pudkon, ab Sulawan Kaowphong, ac Samuel Pattisson, d Peter J. Miedziak, de Hasliza Bahruji, d Thomas E. Davies, d David J. Morgan d and Graham J. Hutchings * d Author affiliations * Corresponding authors a Department of Chemistry, Faculty of

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US20090014094A1 Methods for Reducing Hexavalent

The present invention is directed to trivalent chromate conversion coatings for plated metals, and more particularly, to methods for reducing hexavalent chromium in trivalent chromate conversion coatings. In one embodiment, such method includes placing a metal article having a trivalent chromate conversion coating in a reducing solution.

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Hexavalent Chromium Reduction by Ferrous Sulphate

Hexavalent chromium reduction by ferrous sulphate heptahydrate addition into the Portland clinker Miroslava Monþeková*, Radoslav Novotný, Jan Koplík, Lukáš Kalina, Vlastimil Bílek, František Šoukal Brno University of Technology, Faculty of Chemistry, Materials Research Centre, Purky ova 118, 612 00 Brno, Czech Republic Abstract Nowadays, hexavalent chromium and its content in Portland

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Hexavalent chromium removal by reduction with

DOI: 10.1021/es050486p Corpus ID: 39057480. Hexavalent chromium removal by reduction with ferrous sulfate, coagulation, and filtration: a pilot-scale study. @article{Qin2005HexavalentCR, title={Hexavalent chromium removal by reduction with ferrous sulfate, coagulation, and filtration: a pilot-scale study.}, author={Gang Qin and Michael J. McGuire and Nicole K. Blute and Chad Seidel and

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Bacterial reduction of hexavalent chromium

Reduction of hexavalent chromium by collection strains of bacteria. Mikrobiologiya 55: 962–965. Mikrobiologiya 55: 962–965. Google Scholar

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Reduction Monitoring in the Chromium Wastewater

The hexavalent chromium in this wastewater must be reduced before the water can be discharged. This requires a two-step process: hexavalent chromium (CR 6) is reduced to trivalent chromium (CR 3); and CR 3 is precipitated as chromium hydroxide. As the oxidation reduction potential (ORP) and the speed of the reduction reaction are closely tied

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Characterization of enzymatic reduction of hexavalent

Chromium reduction by Escherichia coli ATCC 33456 quantitatively transferred hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III). The reduced chromium was predominantly present in the external medium. Supernatant fluids of cell extract, obtained by centrifugation at 12,000 and 150,000 x g, showed almost the same Cr(VI) reduction activity, indicating that Cr(VI) reduction by E. coli

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Efficient Removal of Hexavalent Chromium from

Removal of hexavalent chromium had attracted much attention as it is a hazardous contaminant. An electrocoagulation-like technology electro-reduction was applied. The chromium (VI) in the wastewater was reduced to chromium (III) by the electron supplied by electricity power and Fe2+, formed from corrosion of steel electrodes in acidic conditions.

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[Advances in molecular mechanism of bacterial

[Advances in molecular mechanism of bacterial reduction of hexavalent chromium]. [Article in Chinese] Li D, Zhao YC, Song LY, Yin YJ, Wang YQ, Xu ZH. Cr(VI) has been causing serious environmental pollution due to its carcinogenicity, teratogenicity and strong migration. Reduction of Cr( VI) to Cr(III), a precipitation that is much less toxic, is an efficient strategy to control Cr pollution

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