The mechanisms of Co(II) oxidation on synthetic birnessite

Crowther, D.L.; Dillard, John G.; Murray, James

doi:10.1016/0016-7037(83)90298-3

Cited by 111 publications

(60 citation statements)

References 17 publications

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“…Similarity in distributions has been attributed to preferential adsorption of Co onto Mn oxide particles (Murray 1975;Balistrieri and Murray 1986) or chemical oxidation of Co(I1) to Co(II1) once adsorbed onto the Mn oxide particles (Burns 1976;Crowther and Dillard 1983). Balistrieri and Murray ( 1986) reported that deep-sea sediments with high Mn content adsorbed more Co than did Mn-depleted sediment.…”

Section: At Energy Agency 1985)mentioning

confidence: 82%

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Microbially mediated cobalt oxidation in seawater revealed by radiotracer experiments

Lee

Fisher

1993

Limnology & Oceanography

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The influence of microbial activity on Co and Mn oxidation in decomposing diatom cultures was determined with radiotracer techniques. Adding a consortium of microorganisms collected from coastal seawater (0.2-3-km size fraction) to the cultures increased particulate Co formation rates at 18°C by an order of magnitude (to 3.8% d-l) and particulate Mn formation rates 3-fold (to 7.9% d-') over rates in cultures without added microorganisms. The rates of both particulate Co and Mn formation increased with incubation temperature (Q," = 2.5-2.9 for Co and 1.3-l .8 for Mn; T = 4-l PC) and were faster in the dark than in the light. Ascorbic acid (used as a reducing agent) rinses of particulate Co and Mn indicated that these particles were primarily formed by the oxidation of Co(I1) and Mn(I1) to metal oxides. By manipulating Mn: Co ratios we showed that formation of particulate Co is directly mediated by microbial activity rather than Co adsorption to or oxidation by Mn oxides. The results help explain the scavenged-type profile exhibited by Co in the water column and the high K+s of Co in marine sediments.

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Section: At Energy Agency 1985)mentioning

confidence: 82%

“…Energy Agency 198 5), with concentrations in sedimenting particles increasing with depth (Masuzawa et al 1989). This behavior has been attributed to the preferential adsorption of Co onto Mn oxide particles (Murray 1975;Balistrieri and Murray 1986) or chemical oxidation of Co(H) to Co(II1) adsorbed onto Mn oxides (Burns 1976;Crowther and Dillard 1983).…”

mentioning

confidence: 99%

Microbially mediated cobalt oxidation in seawater revealed by radiotracer experiments

Lee

Fisher

1993

Limnology & Oceanography

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“…Only by addition of Cs, which is larger than the interlayer H20 molecules, did the basal spacing change significantly. Hem (1979), Crowther et al (1983), and Krishnamurti and Huang (1987) established that birnessite can act as a catalyst to oxidize aqueous metal ions. Hem (1979Hem ( , 1980 proposed an autocatalytic process to explain how such reactions can occur without releasing large amounts of Mn 2+ to solution.…”

Section: Reaction Schemementioning

confidence: 99%

Reaction Scheme for the Oxidation of as(III) to as(V) by Birnessite

Moore

Walker

Hayes

1990

Clays and clay miner.

100

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Abstract--The oxidation of As(III) to As(V) by K-birnessite was examined at different temperatures, pHs, and birnessite/As(III) ratios. Experiments ranged in duration from 5 to 64 hr, and solution and solid products were determined at several intervals. All experiments showed that the reaction produced large amounts of K + to solution and very little Mn 2+. As(V) was released to solution and incorporated into the K-birnessite. The oxidation was initially rapid and then slowed. The oxidation of As(III) was probably facilitated initially by autocatalytic Mn-As(V) reactions occurring mostly in the interlayer, in which large amounts of As(V) and K + could be easily released to solution. The reaction also slowed when interlayer Mn was exhausted by forming Mn-As(V) complexes. Mn(IV) could only be acquired from the octahedral sheets of the birnessite. The two-stage reaction process proposed here depended on the layered structure of birnessite, the specific surface, and presence of exchangeable cations in K-birnessite.

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“…Later, it was shown that adsorption of cobalt onto Mn oxides did occur and could account for the enrichment of Co found in the particulate layer of the Black Sea (13). Further examination of this particulate-bound cobalt by X-ray photoelectron spectroscopy (16) showed that it had been oxidized from Co(II) to Co(III) at the MnO 2 interface and that Mn(IV) was the oxidant (6).…”

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confidence: 99%

Indirect Oxidation of Co(II) in the Presence of the Marine Mn(II)-Oxidizing Bacterium Bacillus sp. Strain SG-1

Murray

Webb

Bargar

et al. 2007

Appl Environ Microbiol

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Cobalt(II) oxidation in aquatic environments has been shown to be linked to Mn(II) oxidation, a process primarily mediated by bacteria. This work examines the oxidation of Co(II) by the spore-forming marine Mn(II)-oxidizing bacterium Bacillus sp. strain SG-1, which enzymatically catalyzes the formation of reactive nanoparticulate Mn(IV) oxides. Preparations of these spores were incubated with radiotracers and various amounts of Co(II) and Mn(II), and the rates of Mn(II) and Co(II) oxidation were measured. Inhibition of Mn(II) oxidation by Co(II) and inhibition of Co(II) oxidation by Mn(II) were both found to be competitive. However, from both radiotracer experiments and X-ray spectroscopic measurements, no Co(II) oxidation occurred in the complete absence of Mn(II), suggesting that the Co(II) oxidation observed in these cultures is indirect and that a previous report of enzymatic Co(II) oxidation may have been due to very low levels of contaminating Mn. Our results indicate that the mechanism by which SG-1 oxidizes Co(II) is through the production of the reactive nanoparticulate Mn oxide.

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The mechanisms of Co(II) oxidation on synthetic birnessite

Cited by 111 publications

References 17 publications

Microbially mediated cobalt oxidation in seawater revealed by radiotracer experiments

Microbially mediated cobalt oxidation in seawater revealed by radiotracer experiments

Reaction Scheme for the Oxidation of as(III) to as(V) by Birnessite

Indirect Oxidation of Co(II) in the Presence of the Marine Mn(II)-Oxidizing Bacterium Bacillus sp. Strain SG-1

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