Reduction Kinetics of Polymeric (Soluble) Manganese (IV) Oxide (MnO2) by Ferrous Iron (Fe2+)

Siebecker, Matthew G.; Madison, Andrew S.; Luther, George W.

doi:10.1007/s10498-015-9257-z

Cited by 38 publications

(26 citation statements)

References 26 publications

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“…As reported, for the oxidation of Fe 2+ and Cr 3+ by manganese oxides, reaction rate was controlled by chemical reaction and not dependent upon diffusion from the bulk solution or transport of dissolved species from birnessite at pH > 4, and initial reduction rates can be significantly faster than long-term rates because of the inhibition by Fe(III) precipitates [ 20 , 22 , 23 , 43 ]. In this work, the adsorption of Fe 2+ on the surface of birnessite was extremely fast, and it could be proved by the release rate and concentration variation of K + .…”

Section: Resultsmentioning

confidence: 83%

“…All the released Mn 2+ concentrations were lower than the theoretical values. Therefore, all the reductions of birnessite by Fe 2+ were incomplete when Fe 2+ ions were controlled at 10, 20 and 40 mmol L −1 , and the formation of the precipitate of ferric (hydr)oxides including goethite and lepidocrocite possibly inhibited the further reduction of birnessite [ 20 , 22 , 23 , 43 ]. Another possibility should be considered for the low concentration of released Mn 2+ , the formed Mn 2+ would be partially readsorbed on the surface of newly exposed birnessites, resulting in a decrease in released Mn 2+ concentration.…”

Section: Resultsmentioning

confidence: 99%

“…Column experiment was conducted to study the reduction of Mn-oxides by ferrous ions in a flow system, and reactive transport modeling was used to analyze, quantify, and elucidate the different reaction controls and their interaction, and it was found that the release of newly formed Fe 3+ and Mn 2+ would be retarded as they would be first adsorbed on the surface of manganese oxides [ 22 ]. During the redox process, initial reduction rates were much faster than long-term rates because of the inhibition by Fe(III) precipitates in the later stage at higher pH [ 23 ]. The above researches focus on reaction kinetics, which is usually based on the deduced reaction process.…”

Section: Introductionmentioning

confidence: 99%

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Interaction mechanisms and kinetics of ferrous ion and hexagonal birnessite in aqueous systems

et al. 2015

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BackgroundIn soils and sediments, manganese oxides and oxygen usually participate in the oxidation of ferrous ions. There is limited information concerning the interaction process and mechanisms of ferrous ions and manganese oxides. The influence of air (oxygen) on reaction process and kinetics has been seldom studied. Because redox reactions usually occur in open systems, the participation of air needs to be further investigated.ResultsTo simulate this process, hexagonal birnessite was prepared and used to oxidize ferrous ions in anoxic and aerobic aqueous systems. The influence of pH, concentration, temperature, and presence of air (oxygen) on the redox rate was studied. The redox reaction of birnessite and ferrous ions was accompanied by the release of Mn2+ and K+ ions, a significant decrease in Fe2+ concentration, and the formation of mixed lepidocrocite and goethite during the initial stage. Lepidocrocite did not completely transform into goethite under anoxic condition with pH about 5.5 within 30 days. Fe2+ exhibited much higher catalytic activity than Mn2+ during the transformation from amorphous Fe(III)-hydroxide to lepidocrocite and goethite under anoxic conditions. The release rates of Mn2+ were compared to estimate the redox rates of birnessite and Fe2+ under different conditions.ConclusionsRedox rate was found to be controlled by chemical reaction, and increased with increasing Fe2+ concentration, pH, and temperature. The formation of ferric (hydr)oxides precipitate inhibited the further reduction of birnessite. The presence of air accelerated the oxidation of Fe2+ to ferric oxides and facilitated the chemical stability of birnessite, which was not completely reduced and dissolved after 18 days. As for the oxidation of aqueous ferrous ions by oxygen in air, low and high pHs facilitated the formation of goethite and lepidocrocite, respectively. The experimental results illustrated the single and combined effects of manganese oxide and air on the transformation of Fe2+ to ferric oxides.Graphical abstract:Lepidocrocite and goethite were formed during the interaction of ferrous ion and birnessite at pH 4-7. Redox rate was controlled by the adsorption of Fe2+ on the surface of birnessite. The presence of air (oxygen) accelerated the oxidation of Fe2+ to ferric oxides and facilitated the chemical stability of birnessite

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Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Interaction mechanisms and kinetics of ferrous ion and hexagonal birnessite in aqueous systems

et al. 2015

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“…20,67,68 However, these putative Mn(III) intermediates are extremely difficult to detect in reactions with sulfide, even by powerful UV–vis and voltammetry techniques; 69 additionally, Mn(III) is reduced by ferrous iron and sulfide in seconds 70 unless strong Mn(III) ligands are present. 71 Despite evidence for two single-electron transfers to the Mn(IV) surface, these steps appear to be extremely rapid —occurring in seconds 67,72 — and the reported product of Mn(IV) reduction by iron and sulfide without strong Mn(III) ligands present is aqueous Mn 2+ 67,69 . It is possible the brief Mn(III) intermediates in these reactions can undergo hydration and form a temporary MnOOH compound; however, we think that the short-lived Mn(III) intermediates reported in earlier works would have been undetected in our experiments.…”

Section: Resultsmentioning

confidence: 99%

Real-Time Manganese Phase Dynamics during Biological and Abiotic Manganese Oxide Reduction

Johnson

Savalia

Davis

et al. 2016

Environ. Sci. Technol.

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Manganese oxides are often highly reactive and easily reduced, both abiotically, by a variety of inorganic chemical species, and biologically during anaerobic respiration by microbes. To evaluate the reaction mechanisms of these different reduction routes and their potential lasting products, we measured the sequence progression of microbial manganese(IV) oxide reduction mediated by chemical species (sulfide and ferrous iron) and the common metal-reducing microbe Shewanella oneidensis MR-1 under several endmember conditions, using synchrotron X-ray spectroscopic measurements complemented by X-ray diffraction and Raman spectroscopy on precipitates collected throughout the reaction. Crystalline or potentially long-lived phases produced in these experiments included manganese(II)-phosphate, manganese(II)-carbonate, and manganese(III)-oxyhydroxides. Major controls on the formation of these discrete phases were alkalinity production and solution conditions such as inorganic carbon and phosphate availability. The formation of a long-lived Mn(III) oxide appears to depend on aqueous Mn2+ production and the relative proportion of electron donors and electron acceptors in the system. These real-time measurements identify mineralogical products during Mn(IV) oxide reduction, contribute to understanding the mechanism of various Mn(IV) oxide reduction pathways, and assist in interpreting the processes occurring actively in manganese-rich environments and recorded in the geologic record of manganese-rich strata.

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“…2. Biogeochemical cycles of trace metals in freshwater systems This section illustrates approaches based on field studies in lake sediments (Dittrich et al 2015) and wetlands (Davranche et al 2015) but covers also process-oriented research on redox kinetics of manganese oxides (Siebecker et al 2015) and the role of metallophores in trace metal biogeochemistry (Kraemer et al 2015). 3.…”

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confidence: 99%

Laura Sigg: Investigating the Speciation, Bioavailability and Ecotoxicology of Trace Metals in Natural Waters

Wehrli

Behra

2015

Aquat Geochem

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Reduction Kinetics of Polymeric (Soluble) Manganese (IV) Oxide (MnO2) by Ferrous Iron (Fe2+)

Cited by 38 publications

References 26 publications

Interaction mechanisms and kinetics of ferrous ion and hexagonal birnessite in aqueous systems

Interaction mechanisms and kinetics of ferrous ion and hexagonal birnessite in aqueous systems

Real-Time Manganese Phase Dynamics during Biological and Abiotic Manganese Oxide Reduction

Laura Sigg: Investigating the Speciation, Bioavailability and Ecotoxicology of Trace Metals in Natural Waters

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