The oxidation of Fe(II) with H2O2 in seawater

Millero, Frank J.; Sotolongo, Sara

doi:10.1016/0016-7037(89)90307-4

Cited by 265 publications

(197 citation statements)

References 18 publications

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“…Typically half-lives for the oxidation were around 90 min, consistent with extrapolation of the laboratory data of Millero and Sotolongo (1989) and Millero et al (1987) The lowest temperatures at which laboratory Fe(II) oxidation experiments have been reported in the literature is at 5 8C (Kuma et al, 1992(Kuma et al, , 1995Millero and Sotolongo, 1989;Millero et al, 1987) with most experimental data having been obtained at 25 8C. Similarly King and coworkers have shown the importance of carbonate speciation on the oxidation of Fe(II) by O 2 (King, 1998) and by H 2 O 2 (King and Farlow, 2000).…”

Section: Fe(ii) Oxidation Ratessupporting

confidence: 76%

“…For the present case, we used the 25 8C value when no other value was available. As the effect of temperature on the oxidation rates of Fe(II) for O 2 and H 2 O 2 are caused largely by the enthalpy change for K w (Millero and Sotolongo, 1989;Millero et al, 1987), it may be possible to correct the O 2 À similarly, but this has not been pursued here. Fig.…”

Section: Model Resultsmentioning

confidence: 99%

“…The pH data used in this study were computed using the dtotal hydrogen ion concentration scaleT. The Fe(II) oxidation rate data of Millero and Sotolongo (1989) and Millero et al (1987) were corrected from the free pH scale (Tris buffers in seawater) used in that work, to the total hydrogen ion concentration scale using the appropriate algorithms (DOE, 1994).…”

Section: Underway Phmentioning

confidence: 99%

“…This Fe II source is significantly more soluble than Fe III , the thermodynamically favoured form; however, Fe II is rapidly oxidised to Fe III by O 2 and H 2 O 2 in warm waters (Millero and Sotolongo, 1989;Millero et al, 1987). Fe III rapidly forms complexes with hydroxide with subsequent formation of colloidal oxyhydroxide (Kuma et al, 1996) species which lately coagulate and form particulate iron (Johnson et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

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Spatial and temporal distribution of Fe(II) and H2O2 during EisenEx, an open ocean mescoscale iron enrichment

et al. 2005

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Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. concentrations increased at the depth of the chlorophyll maximum when iron concentrations returned to pre-infusion concentrations (b80 pM) possibly due to biological production related to iron reductase activity.In this work, Fe(II) and dissolved iron were used as tracers themselves for subsequent iron infusions when no further SF 6 was added. EisenEx was subject to periods of weak and strong mixing. Slow mixing after the second infusion allowed significant concentrations of Fe(II) and Fe to exist for several days. During this time, dissolved and total iron in the infusion plume behaved almost conservatively as it was trapped between a relict mixed layer and a new rain-induced mixed layer. Using dissolved iron, a value for the vertical diffusion coefficient K z =6.7F0.7 cm 2 s À1 was obtained for this 2-day period. During a subsequent surface survey of the iron-enriched patch, elevated levels of Fe(II) were found in surface waters presumably from Fe(II) dissolved in the rainwater that was falling at this time.Model results suggest that the reaction between uncomplexed Fe(III) and O 2 À was a significant source of Fe(II) during EisenEx and helped to maintain high levels of Fe(II) in the water column. This phenomenon may occur in iron enrichment experiments when two conditions are met: (i) When Fe is added to a system already saturated with regard to organic complexation and (ii) when mixing processes are slow, thereby reducing the dispersion of iron into under-saturated waters. D

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Section: Fe(ii) Oxidation Ratessupporting

confidence: 76%

Section: Model Resultsmentioning

confidence: 99%

Section: Underway Phmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spatial and temporal distribution of Fe(II) and H2O2 during EisenEx, an open ocean mescoscale iron enrichment

et al. 2005

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“…It is rapidly oxidized to iron(III) in the euphotic zone by hydrogen peroxide, oxygen (Millero and Sotolongo 1989), superoxide (O 2 -), and hydroxyl radical (OH) (Millero 1989). Therefore, iron(III) is the dominant form of dissolved iron in surface seawater (Millero and Sotolongo 1989;Achterberg et al 2001); however, only a small fraction of iron(III) occurs in a free hydrated (Fe 3+ ) form.…”

Section: Introductionmentioning

confidence: 99%

Sequential injection trace determination of iron in natural waters using a long‐pathlength liquid core waveguide and different spectrophotometric chemistries

Páscoa

Tóth

Rangel

2009

Limnology & Ocean Methods

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We developed a sequential injection analysis (SIA) method for the determination of iron in coastal, ground, and surface fresh waters using two different reagents (ferrozine and 1,10-phenathroline). The methodology uses a double-line SIA system to improve mixing conditions between sample and reagent solutions. A liquid waveguide capillary cell (LWCC) with 1.0 m pathlength, 550 µm i.d., and 250 µL internal volume was used to enhance the sensitivity of the determination. The detection limits for the ferrozine and 1,10-phenanthroline reagent were 0.15 and 0.35 µg L -1 , respectively. The system provides a linear response up to 20 µg L -1 and has a high throughput rate (41 h -1 ), low reagent consumption, and also low effluent production for both reagents. The developed method was applied to natural waters (river, well, ground, potable, and sea waters) and one reference water sample.

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Determination of Iron Speciation by Cathodic Stripping Voltammetry in Seawater Using the Competing Ligand 2-(2-Thiazolylazo)-p-cresol (TAC)

2000

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A new sensitive competitive ligand exchange‐adsorptive cathodic stripping voltammetric (CLE‐ACSV) method for the determination of iron speciation in seawater has been developed using the iron binding ligand TAC 2‐(2‐thiazolylazo)‐p‐cresol. An earlier method for determining iron using TAC [1] was reexamined and optimized for measurements in seawater at pH 8.0. The sensitivity was improved by employing a fast (10.12 V/s) linear sweep scan waveform. The detection limit (3σ of blank) is 0.10 nM after an adsorption time of 300 s; the detection limit can be lowered, however, by using a longer deposition time or for the determination of total iron, by increasing the pH to 8.5. This method was applied to samples from Swedish coastal waters and the results indicate the possible efflux of iron binding ligands from sediments in coastal waters.

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The oxidation of Fe(II) with H2O2 in seawater

Cited by 265 publications

References 18 publications

Spatial and temporal distribution of Fe(II) and H2O2 during EisenEx, an open ocean mescoscale iron enrichment

Spatial and temporal distribution of Fe(II) and H2O2 during EisenEx, an open ocean mescoscale iron enrichment

Sequential injection trace determination of iron in natural waters using a long‐pathlength liquid core waveguide and different spectrophotometric chemistries

Determination of Iron Speciation by Cathodic Stripping Voltammetry in Seawater Using the Competing Ligand 2-(2-Thiazolylazo)-p-cresol (TAC)

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