Kinetics of chromium(VI) reduction by ferrous iron

Batchelor, Bill; Schlautman, Mark A.; Hwang, Inseong; Wang, Run

doi:10.2172/290853

Cited by 5 publications

(3 citation statements)

References 5 publications

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“…There are cases of chromium oxidation of the (-2 to +6), but only two oxidation states (Cr +3 , Cr +6 ) are stable under the most natural aquatic environments (19). The geochemical behavior and toxicity to lives (Biological Toxicity) of Cr in both cases varies since the (Cr VI) tends to become negative dissolved ionic forms or types of natural insoluble, can be high mobility and is acutely toxic to the contrary, (Cr III) tends to precipitate in a positive dissolved ionic species and is immobile under basic conditions and weak acidic conditions and relatively nontoxic (20).…”

Section: -Chromium (Cr)mentioning

confidence: 99%

Distribution of Heavy Metals in Parts of Diyala River (Basin), Iraq

2017

IJSR

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Diyala River (Middle-Lower) Basin water was analyzed for (Cd, Co, Cr, Cu, Ni, Pb and Zn ) in order to determine; heavy metals distribution, pollution sources, the influence of human activities and natural processes. Ten water samples were collected along Diyala River from Kalar region to the meeting point of Diyala river and Tigris river southern Baghdad city. The results had been shown that Cd, Co, Cr, Ni and Pb concentrations were higher than the acceptable limits of the WHO, 2006 guideline and Iraqi guideline, 2009 for drinking water, while Cu and Zn concentrations were within acceptable limits a according to the mentioned guidelines. The most enriched metals were Cr and Pb, and the occurrence of metal generally ranked in the order Cr > Pb > (Zn, Ni, Co) > Cu > Cd. The occurrence of these heavy metals contributed as a result of both natural processes and human resources of pollution and affected by many chemical variables in aquatic environment such as; pH, oxidation states, oxidation and reduction effort, mobility, organic matter and hardness. These heavy metals considerable polluted elements to water. The presence of heavy metals above the acceptable limits could be toxic to aquatic organisms and harmful to human beings and that toxicity can cause several health effects.

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Section: -Chromium (Cr)mentioning

confidence: 99%

Distribution of Heavy Metals in Parts of Diyala River (Basin), Iraq

2017

IJSR

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“…Heavy metals continue to pose environmental treats when present in contaminated soils. Cr(VI) is of concern because of the broad range of industrial processes that are sources of Cr(VI) contamination of soil and groundwater ( , ). The persistence of Cr(VI) in these media suggests the continuing need for a variety of suitable techniques of treatment ( − ).…”

Section: Introductionmentioning

confidence: 99%

“…Cr(VI) is of concern because of the broad range of industrial processes that are sources of Cr(VI) contamination of soil and groundwater ( , ). The persistence of Cr(VI) in these media suggests the continuing need for a variety of suitable techniques of treatment ( − ). A widely accepted method to reduce the impact of chromium in the environment is to convert Cr(VI) to the less toxic and less mobile Cr(III) ( − ).…”

Section: Introductionmentioning

confidence: 99%

Enhanced Reduction of Cr(VI) by Direct Electric Current in a Contaminated Clay

Pamukcu

Weeks

Wittle

2004

Environ. Sci. Technol.

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The probable relation between diffuse double-layer processes and redox reactions that enhance degradation or conversion of contaminants under an applied electric field were examined in a clay medium. Kaolinite clay, precontaminated with hexavalent chromium, was the test soil medium. Analyte, containing ferrous iron, was transported through the kaolinite clay using direct electric current. The Cr(VI) reduction to Cr(III) was followed by measuring the soil redox potential and pH at discrete locations in the clay bed. The post-test distribution of Cr showed significantly more Cr(III) than Cr(VI) at low to slightly acidic pH distribution (2 < pH < 6) in clay. The stoichiometric analyses of measured chromium and iron species concentrations versus the measured redox potentials were compared to Nernst equation predictions of an equivalent aqueous system. An average of +0.37 V shift was measured from the linear Nernstian prediction of cell potential. The applied electric field appeared to provide additional “cathodic current” to drive forth the redox reactions. The redox potential shift was explained by possible overpotential development at the clay−water interfaces due to double-layer polarization under the applied field.

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