A Kinetic Study of the Reduction of Colloidal Manganese Dioxide by Oxalic Acid

Perez‐Benito, Joaquin F.; Arias, Conchita; Amat, E.

doi:10.1006/jcis.1996.0034

Cited by 148 publications

(83 citation statements)

References 19 publications

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“…These characteristics were consistent with the characterization of the colloidal oxide by PerezBenito et al (24). We added this solution in a range of concentrations to a premixed aliquot of distilled water, HEPES buffer and 100 μM Cr(III).…”

Section: Cr(iii) Oxidation By Colloidal Mnosupporting

confidence: 83%

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Cr(III) Is Indirectly Oxidized by the Mn(II)-Oxidizing Bacterium Bacillus sp. Strain SG-1

Murray

Tebo

2006

Environ. Sci. Technol.

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Manganese oxides are the only known oxidants of Cr(III) in the environment, and predictions of the fate of Cr(III) have been based on Cr(III) oxidation rates with well-characterized Mn(III,IV) oxide minerals. Our research, however, indicates that the presence of Mn(II)-oxidizing bacteria, may accelerate these rates through the production of very reactive Mn oxides or intermediates formed in the oxidation process. Experiments with the Mn(II)-oxidizing Bacillus sp. strain SG-1 show that this bacterium can accelerate Cr(III) oxidation compared to both abiotic and biologically produced Mn oxides. Initial rates of Cr(III) oxidation by biogenic oxides were approximately 7 times faster than Cr(III) oxidation rates by equivalent amounts of synthetic δ-MnO 2 and 25 times faster by SG-1 spores with Mn(II). Cr(III) oxidation by SG-1 is not direct; Mn is required, but only in small amounts, indicating that it is recycled. Cr(III) oxidation is inhibited above 5 μM dissolved Mn(II), while Mn(II) oxidation is not, suggesting that the processes are controlled by different mechanisms. These results illustrate the need to consider bacterial activity and the concentration of Mn when predicting the potential for Cr(III) oxidation.

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Section: Cr(iii) Oxidation By Colloidal Mnosupporting

confidence: 83%

“…Colloidal Mn oxide was prepared according to Perez-Benito et al (24). Ten ml of 100 mM KMnO4 was brought up to 50 mL with distilled water and titrated with 18.8 mM Na 2 S 2 O 3 while being stirred until the pink color of the permanganate was not visible in solution after filtration with a 0.02 μM syringe filter.…”

Section: Synthesis Of Abiotic Mn Oxidesmentioning

confidence: 99%

Cr(III) Is Indirectly Oxidized by the Mn(II)-Oxidizing Bacterium Bacillus sp. Strain SG-1

Murray

Tebo

2006

Environ. Sci. Technol.

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“…Colloidal Mn oxide was prepared according to the method of Perez-Benito et al (19). Ten milliliters of 100 mM KMnO 4 was brought up to 50 ml with distilled water and titrated with 18.8 mM Na 2 S 2 O 3 while being stirred until the pink color of the permanganate was not visible in solution after filtration with a 0.02-m syringe filter.…”

Section: Methodsmentioning

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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“…In the present study, oxalate production seems to have an important role in the solubilization of Mn and Ni. Oxalate-promoted dissolution of Mn oxides by reduction of Mn(IV) to Mn(II) has been proposed by several authors (36)(37)(38). The higher concentrations of Ni released into the culture medium (or the redistribution of Ni toward labile phases) may be related to the ability of strain LA44 to create reducing conditions.…”

Section: Discussionmentioning

confidence: 97%

Bacterially Induced Weathering of Ultramafic Rock and Its Implications for Phytoextraction

Becerra-Castro

Kidd

Kuffner

et al. 2013

Appl Environ Microbiol

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The bioavailability of metals in soil is often cited as a limiting factor of phytoextraction (or phytomining). Bacterial metabolites, such as organic acids, siderophores, or biosurfactants, have been shown to mobilize metals, and their use to improve metal extraction has been proposed. In this study, the weathering capacities of, and Ni mobilization by, bacterial strains were evaluated. Minimal medium containing ground ultramafic rock was inoculated with either of two Arthrobacter strains: LA44 (indole acetic acid [IAA] producer) or SBA82 (siderophore producer, PO 4 solubilizer, and IAA producer). Trace elements and organic compounds were determined in aliquots taken at different time intervals after inoculation. Trace metal fractionation was carried out on the remaining rock at the end of the experiment. The results suggest that the strains act upon different mineral phases. LA44 is a more efficient Ni mobilizer, apparently solubilizing Ni associated with Mn oxides, and this appeared to be related to oxalate production. SBA82 also leads to release of Ni and Mn, albeit to a much lower extent. In this case, the concurrent mobilization of Fe and Si indicates preferential weathering of Fe oxides and serpentine minerals, possibly related to the siderophore production capacity of the strain. The same bacterial strains were tested in a soil-plant system: the Ni hyperaccumulator Alyssum serpyllifolium subsp. malacitanum was grown in ultramafic soil in a rhizobox system and inoculated with each bacterial strain. At harvest, biomass production and shoot Ni concentrations were higher in plants from inoculated pots than from noninoculated pots. Ni yield was significantly enhanced in plants inoculated with LA44. These results suggest that Ni-mobilizing inoculants could be useful for improving Ni uptake by hyperaccumulator plants.

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A Kinetic Study of the Reduction of Colloidal Manganese Dioxide by Oxalic Acid

Cited by 148 publications

References 19 publications

Cr(III) Is Indirectly Oxidized by the Mn(II)-Oxidizing Bacterium Bacillus sp. Strain SG-1

Cr(III) Is Indirectly Oxidized by the Mn(II)-Oxidizing Bacterium Bacillus sp. Strain SG-1

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

Bacterially Induced Weathering of Ultramafic Rock and Its Implications for Phytoextraction

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