Oxygen Isotope Evidence for Mn(II)-Catalyzed Recrystallization of Manganite (γ-MnOOH)

Andrew J Frierdich, Michael J Spicuzza, Michelle M Scherer

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Manganese is biogeochemically cycled between aqueous Mn(II) and Mn(IV) oxides. Aqueous Mn(II) often coexists with Mn(IV) oxides, and redox reactions between thetwo (e.g., comproportionation) are well known to result in the formation of Mn(III) minerals. It is unknown, however,whether aqueous Mn(II) exchanges with structural Mn(III) in manganese oxides in the absence of any mineral transformation(similar to what has been reported for aqueous Fe(II) and some Fe(III) minerals). To probe whether atoms exchange between a Mn(III) oxide and water, we use a 17O tracer to measure oxygen isotope exchange between structural oxygen in manganite (γ-MnOOH) and water. In the absence of aqueous Mn(II), about 18% of the oxygen atoms in manganite exchange with the aqueous phase, which is close to the estimated surface oxygen atoms (∼11%). In the presence of aqueous Mn(II), an additional 10% (for a total of 28%) of the oxygen atoms exchange with water, suggesting that some of the bulk manganite mineral (i.e., beyond surface) is exchanging with the fluid. Exchange of manganite oxygen with water occurs without any observable change in mineral phase and appears to be independent of the rapid Mn(II) sorption kinetics. These experiments suggest that Mn(II) catalyzes manganese oxide recrystallization and illustrate a new pathway by which these ubiquitous minerals interact with their surrounding fluid.
Original languageEnglish
Pages (from-to)6374−6380
Number of pages7
JournalEnvironmental Science and Technology
Volume50
Issue number12
DOIs
Publication statusPublished - 2016

Cite this

Frierdich, Andrew J ; Spicuzza, Michael J ; Scherer, Michelle M. / Oxygen Isotope Evidence for Mn(II)-Catalyzed Recrystallization of Manganite (γ-MnOOH). In: Environmental Science and Technology. 2016 ; Vol. 50, No. 12. pp. 6374−6380.
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title = "Oxygen Isotope Evidence for Mn(II)-Catalyzed Recrystallization of Manganite (γ-MnOOH)",
abstract = "Manganese is biogeochemically cycled between aqueous Mn(II) and Mn(IV) oxides. Aqueous Mn(II) often coexists with Mn(IV) oxides, and redox reactions between thetwo (e.g., comproportionation) are well known to result in the formation of Mn(III) minerals. It is unknown, however,whether aqueous Mn(II) exchanges with structural Mn(III) in manganese oxides in the absence of any mineral transformation(similar to what has been reported for aqueous Fe(II) and some Fe(III) minerals). To probe whether atoms exchange between a Mn(III) oxide and water, we use a 17O tracer to measure oxygen isotope exchange between structural oxygen in manganite (γ-MnOOH) and water. In the absence of aqueous Mn(II), about 18{\%} of the oxygen atoms in manganite exchange with the aqueous phase, which is close to the estimated surface oxygen atoms (∼11{\%}). In the presence of aqueous Mn(II), an additional 10{\%} (for a total of 28{\%}) of the oxygen atoms exchange with water, suggesting that some of the bulk manganite mineral (i.e., beyond surface) is exchanging with the fluid. Exchange of manganite oxygen with water occurs without any observable change in mineral phase and appears to be independent of the rapid Mn(II) sorption kinetics. These experiments suggest that Mn(II) catalyzes manganese oxide recrystallization and illustrate a new pathway by which these ubiquitous minerals interact with their surrounding fluid.",
author = "Frierdich, {Andrew J} and Spicuzza, {Michael J} and Scherer, {Michelle M}",
year = "2016",
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language = "English",
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journal = "Environmental Science and Technology",
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}

Oxygen Isotope Evidence for Mn(II)-Catalyzed Recrystallization of Manganite (γ-MnOOH). / Frierdich, Andrew J; Spicuzza, Michael J; Scherer, Michelle M.

In: Environmental Science and Technology, Vol. 50, No. 12, 2016, p. 6374−6380.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Oxygen Isotope Evidence for Mn(II)-Catalyzed Recrystallization of Manganite (γ-MnOOH)

AU - Frierdich, Andrew J

AU - Spicuzza, Michael J

AU - Scherer, Michelle M

PY - 2016

Y1 - 2016

N2 - Manganese is biogeochemically cycled between aqueous Mn(II) and Mn(IV) oxides. Aqueous Mn(II) often coexists with Mn(IV) oxides, and redox reactions between thetwo (e.g., comproportionation) are well known to result in the formation of Mn(III) minerals. It is unknown, however,whether aqueous Mn(II) exchanges with structural Mn(III) in manganese oxides in the absence of any mineral transformation(similar to what has been reported for aqueous Fe(II) and some Fe(III) minerals). To probe whether atoms exchange between a Mn(III) oxide and water, we use a 17O tracer to measure oxygen isotope exchange between structural oxygen in manganite (γ-MnOOH) and water. In the absence of aqueous Mn(II), about 18% of the oxygen atoms in manganite exchange with the aqueous phase, which is close to the estimated surface oxygen atoms (∼11%). In the presence of aqueous Mn(II), an additional 10% (for a total of 28%) of the oxygen atoms exchange with water, suggesting that some of the bulk manganite mineral (i.e., beyond surface) is exchanging with the fluid. Exchange of manganite oxygen with water occurs without any observable change in mineral phase and appears to be independent of the rapid Mn(II) sorption kinetics. These experiments suggest that Mn(II) catalyzes manganese oxide recrystallization and illustrate a new pathway by which these ubiquitous minerals interact with their surrounding fluid.

AB - Manganese is biogeochemically cycled between aqueous Mn(II) and Mn(IV) oxides. Aqueous Mn(II) often coexists with Mn(IV) oxides, and redox reactions between thetwo (e.g., comproportionation) are well known to result in the formation of Mn(III) minerals. It is unknown, however,whether aqueous Mn(II) exchanges with structural Mn(III) in manganese oxides in the absence of any mineral transformation(similar to what has been reported for aqueous Fe(II) and some Fe(III) minerals). To probe whether atoms exchange between a Mn(III) oxide and water, we use a 17O tracer to measure oxygen isotope exchange between structural oxygen in manganite (γ-MnOOH) and water. In the absence of aqueous Mn(II), about 18% of the oxygen atoms in manganite exchange with the aqueous phase, which is close to the estimated surface oxygen atoms (∼11%). In the presence of aqueous Mn(II), an additional 10% (for a total of 28%) of the oxygen atoms exchange with water, suggesting that some of the bulk manganite mineral (i.e., beyond surface) is exchanging with the fluid. Exchange of manganite oxygen with water occurs without any observable change in mineral phase and appears to be independent of the rapid Mn(II) sorption kinetics. These experiments suggest that Mn(II) catalyzes manganese oxide recrystallization and illustrate a new pathway by which these ubiquitous minerals interact with their surrounding fluid.

U2 - 10.1021/acs.est.6b01463

DO - 10.1021/acs.est.6b01463

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