The effect of organic compounds in the oxidation kinetics of Cr(III) by H2O2

Pettine, M.; Gennari, Francesca; Campanella, Luigí; Millero, Frank J.

doi:10.1016/j.gca.2008.09.009

Cited by 33 publications

(20 citation statements)

References 54 publications

(94 reference statements)

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“…On the other hand, Cr(III) is slowly oxidized back to Cr(VI) for instance by H2O2 (Pettine et al, 2008). Hydrogen peroxide concentrations decrease with depth due to photochemical production, atmospheric deposition to surface waters, and subsequent decomposition (Kieber et al, 2001).…”

Section: Internal Cyclingmentioning

confidence: 99%

Modeling the marine chromium cycle: New constraints on global-scale processes

Pöppelmeier

Janssen

Jaccard

et al. 2021

Preprint

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Abstract. Chromium (Cr) and its isotopes hold great promise as tracer of past oxygenation and marine biological activity due to the different chemical properties of its two main oxidation states, Cr(III) and Cr(VI), and the associated fractionation during redox transformations. However, to date the Cr cycle remains poorly constrained due to insufficient knowledge about sources and sinks and the influence of biological activity on redox reactions. We therefore implemented the two oxidation states of Cr in the Bern3D Earth system model of intermediate complexity, in order to gain an improved understanding on the mechanisms that modulate the spatial distribution of Cr in the ocean. Due to the computational efficiency of the Bern3D model we are able to explore and constrain the range of a wide array of parameters. Our model simulates vertical, meridional, and inter-basin Cr concentration gradients in good agreement with observations. We find a mean ocean residence time of Cr between 5 and 8 kyr, and a benthic flux, emanating from all sediment surfaces, of of 0.1–0.2 nmol cm-2 yr-1, both in the range of previous estimates. We further explore the origin of regional model-data mismatches through a number of sensitivity experiments. These indicate that the benthic Cr flux may be substantially lower in the Arctic than elsewhere. In addition, we find that a refined representation of oxygen minimum zones and their Cr redox potential yields Cr(III) concentrations and Cr removal rates in much improved agreement with observational data.

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Section: Internal Cyclingmentioning

confidence: 99%

Modeling the marine chromium cycle: New constraints on global-scale processes

Pöppelmeier

Janssen

Jaccard

et al. 2021

Preprint

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“…However, little is known about the rate of oxidation of Cr(III)-organic complexes by H 2 O 2 . Pettine et al (2008) reported that monohydroxamic acids are able to bind with Cr(III) and can increase the oxidation rates of Cr(III) with H 2 O 2 by a factor of 3.5 when acetohydroxamic acid was used as ligand, whereas Desferal (a natural siderophore) and EDTA do not have a great effect on the oxidation of Cr(III) with H 2 O 2 (Pettine et al, 2008). This study aims to characterise the mechanism and kinetics of oxidation of Cr(III)-organic complexes by H 2 O 2 .…”

Section: Introductionmentioning

confidence: 99%

Kinetics of oxidation of Cr(III)-organic complexes by H₂O₂

Luo

Chatterjee

2010

Chemical Speciation & Bioavailability

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“…Thanks to recently developed techniques allowing direct detection of O { 2 in marine water samples (Rose et al 2008a,b), interest is growing in its role as a reductant or oxidant of redoxactive trace metals in the ocean. Reactions with H 2 O 2 have also been suggested to be important to the marine redox cycling of Cu (Moffett and Zika 1987), Fe (Moffett and Zika 1987;Millero and Sotolongo 1989), Mn (Sunda and Huntsman 1994), and Cr (Pettine et al 2008).…”

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confidence: 99%

Dark production of hydrogen peroxide in the Gulf of Alaska

Vermilyea

Hansard

Voelker

2010

Limnology & Oceanography

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Dark H2O2 production rates were measured in samples collected in the Gulf of Alaska. We used a simple, novel method for determining absolute rates of dark production and decay of H2O2, both of which are occurring simultaneously (presumably as a result of biological activity) in unfiltered samples. [H2O2] vs. time was measured in 24‐h dark incubations of both unaltered samples and the same samples spiked with 100–250 nmol L−1 H2O2. Data were modeled with zero‐order H2O2 production rates and first‐order H2O2 decay coefficients as fitting parameters, with the assumption that addition of [H2O2] to a sample does not change either parameter. H2O2 production rates ranged from < 0.5 nmol L−1 h−1 to 8 nmol L−1 h−1, and generally decreased with depth and decreasing chlorophyll. Comparison of dark production with estimates of average photochemical H2O2 production rates in the top 50 m of the water column indicated that dark production is likely to be a significant source of H2O2. Indeed, many of the unaltered incubations indicated that in situ [H2O2] was close to a steady state between dark production and decay, especially in samples from depths of ≥ 10 m.

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The effect of organic compounds in the oxidation kinetics of Cr(III) by H2O2

Cited by 33 publications

References 54 publications

Modeling the marine chromium cycle: New constraints on global-scale processes

Modeling the marine chromium cycle: New constraints on global-scale processes

Kinetics of oxidation of Cr(III)-organic complexes by H₂O₂

Dark production of hydrogen peroxide in the Gulf of Alaska

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The effect of organic compounds in the oxidation kinetics of Cr(III) by H2O2

Cited by 33 publications

References 54 publications

Modeling the marine chromium cycle: New constraints on global-scale processes

Modeling the marine chromium cycle: New constraints on global-scale processes

Kinetics of oxidation of Cr(III)-organic complexes by H2O2

Dark production of hydrogen peroxide in the Gulf of Alaska

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Kinetics of oxidation of Cr(III)-organic complexes by H₂O₂