Redox Reactivity of Iron Minerals in the Geosphere

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Environmental Mineralogy and Biogeochemistry".

Deadline for manuscript submissions: closed (31 July 2021) | Viewed by 17258

Special Issue Editors


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Guest Editor
Biogeochemical Processes Group, Biosciences Division, Argonne National Laboratory, Building 203, Room E-137, 9700 South Cass Avenue, Argonne, IL 60439, USA
Interests: biogeochemistry; geomicrobiology; geochemistry; biomineralization; microbial transformations of minerals
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Guest Editor
Department of Earth and Environmental Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea
Interests: microbial biogeochemistry; geomicrobiology; bioremediation

Special Issue Information

Iron is a highly abundant element in the lithosphere, and Fe oxides, Fe-bearing clay minerals, and Fe sulfides are common constituents of soils and sediments. As such, redox-active Fe-bearing minerals are key players in electron transfer reactions involved in the biogeochemical cycling of elements and the transformation of organic and inorganic contaminants in both natural and engineered redox dynamic environments.

We invite contributions on, but not limited to, laboratory and field studies of the transformations of Fe-bearing minerals by abiotic and microbially-driven redox reactions; the coupling of redox reactions of Fe-bearing minerals with the biogeochemical cycling of critical elements (e.g., N, P, and S); and impacts of Fe redox reactions on contaminant transformation, fate, and transport in aquatic and terrestrial environments. We especially encourage multidisciplinary studies that use cutting-edge approaches such as advanced imaging and spectroscopic techniques, isotopic analysis, and omics-based molecular microbiology.

Dr. Edward J. O'Loughlin
Prof. Dr. Man Jae Kwon
Guest Editors

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Keywords

  • Biomineralization
  • Iron oxides
  • Iron sulfides
  • Transformation
  • Contaminants
  • Mineralization

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Published Papers (5 papers)

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Research

21 pages, 13257 KiB  
Article
Reduction of Vanadium(V) by Iron(II)-Bearing Minerals
by Edward J. O’Loughlin, Maxim I. Boyanov and Kenneth M. Kemner
Minerals 2021, 11(3), 316; https://doi.org/10.3390/min11030316 - 18 Mar 2021
Cited by 23 | Viewed by 3831
Abstract
Fe(II)-bearing minerals (magnetite, siderite, green rust, etc.) are common products of microbial Fe(III) reduction, and they provide a reservoir of reducing capacity in many subsurface environments that may contribute to the reduction of redox active elements such as vanadium; which can exist as [...] Read more.
Fe(II)-bearing minerals (magnetite, siderite, green rust, etc.) are common products of microbial Fe(III) reduction, and they provide a reservoir of reducing capacity in many subsurface environments that may contribute to the reduction of redox active elements such as vanadium; which can exist as V(V), V(IV), and V(III) under conditions typical of near-surface aquatic and terrestrial environments. To better understand the redox behavior of V under ferrugenic/sulfidogenic conditions, we examined the interactions of V(V) (1 mM) in aqueous suspensions containing 50 mM Fe(II) as magnetite, siderite, vivianite, green rust, or mackinawite, using X-ray absorption spectroscopy at the V K-edge to determine the valence state of V. Two additional systems of increased complexity were also examined, containing either 60 mM Fe(II) as biogenic green rust (BioGR) or 40 mM Fe(II) as a mixture of biogenic siderite, mackinawite, and magnetite (BioSMM). Within 48 h, total solution-phase V concentrations decreased to <20 µM in all but the vivianite and the biogenic BiSMM systems; however, >99.5% of V was removed from solution in the BioSMM and vivianite systems within 7 and 20 months, respectively. The most rapid reduction was observed in the mackinawite system, where V(V) was reduced to V(III) within 48 h. Complete reduction of V(V) to V(III) occurred within 4 months in the green rust system, 7 months in the siderite system, and 20 months in the BioGR system. Vanadium(V) was only partially reduced in the magnetite, vivianite, and BioSMM systems, where within 7 months the average V valence state stabilized at 3.7, 3.7, and 3.4, respectively. The reduction of V(V) in soils and sediments has been largely attributed to microbial activity, presumably involving direct enzymatic reduction of V(V); however the reduction of V(V) by Fe(II)-bearing minerals suggests that abiotic or coupled biotic–abiotic processes may also play a critical role in V redox chemistry, and thus need to be considered in modeling the global biogeochemical cycling of V. Full article
(This article belongs to the Special Issue Redox Reactivity of Iron Minerals in the Geosphere)
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44 pages, 12998 KiB  
Article
Effects of Fe(III) Oxide Mineralogy and Phosphate on Fe(II) Secondary Mineral Formation during Microbial Iron Reduction
by Edward J. O’Loughlin, Maxim I. Boyanov, Christopher A. Gorski, Michelle M. Scherer and Kenneth M. Kemner
Minerals 2021, 11(2), 149; https://doi.org/10.3390/min11020149 - 31 Jan 2021
Cited by 22 | Viewed by 3984
Abstract
The bioreduction of Fe(III) oxides by dissimilatory iron-reducing bacteria may result in the formation of a suite of Fe(II)-bearing secondary minerals, including magnetite (a mixed Fe(II)/Fe(III) oxide), siderite (Fe(II) carbonate), vivianite (Fe(II) phosphate), chukanovite (ferrous hydroxy carbonate), and green rusts (mixed Fe(II)/Fe(III) hydroxides). [...] Read more.
The bioreduction of Fe(III) oxides by dissimilatory iron-reducing bacteria may result in the formation of a suite of Fe(II)-bearing secondary minerals, including magnetite (a mixed Fe(II)/Fe(III) oxide), siderite (Fe(II) carbonate), vivianite (Fe(II) phosphate), chukanovite (ferrous hydroxy carbonate), and green rusts (mixed Fe(II)/Fe(III) hydroxides). In an effort to better understand the factors controlling the formation of specific Fe(II)-bearing secondary minerals, we examined the effects of Fe(III) oxide mineralogy, phosphate concentration, and the availability of an electron shuttle (9,10-anthraquinone-2,6-disulfonate, AQDS) on the bioreduction of a series of Fe(III) oxides (akaganeite, feroxyhyte, ferric green rust, ferrihydrite, goethite, hematite, and lepidocrocite) by Shewanella putrefaciens CN32, and the resulting formation of secondary minerals, as determined by X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy. The overall extent of Fe(II) production was highly dependent on the type of Fe(III) oxide provided. With the exception of hematite, AQDS enhanced the rate of Fe(II) production; however, the presence of AQDS did not always lead to an increase in the overall extent of Fe(II) production and did not affect the types of Fe(II)-bearing secondary minerals that formed. The effects of the presence of phosphate on the rate and extent of Fe(II) production were variable among the Fe(III) oxides, but in general, the highest loadings of phosphate resulted in decreased rates of Fe(II) production, but ultimately higher levels of Fe(II) than in the absence of phosphate. In addition, phosphate concentration had a pronounced effect on the types of secondary minerals that formed; magnetite and chukanovite formed at phosphate concentrations of ≤1 mM (ferrihydrite), <~100 µM (lepidocrocite), 500 µM (feroxyhyte and ferric green rust), while green rust, or green rust and vivianite, formed at phosphate concentrations of 10 mM (ferrihydrite), ≥100 µM (lepidocrocite), and 5 mM (feroxyhyte and ferric green rust). These results further demonstrate that the bioreduction of Fe(III) oxides, and accompanying Fe(II)-bearing secondary mineral formation, is controlled by a complex interplay of mineralogical, geochemical, and microbiological factors. Full article
(This article belongs to the Special Issue Redox Reactivity of Iron Minerals in the Geosphere)
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13 pages, 1248 KiB  
Article
Reduction of Hg(II) by Fe(II)-Bearing Smectite Clay Minerals
by Edward J. O’Loughlin, Maxim I. Boyanov, Kenneth M. Kemner and Korbinian O. Thalhammer
Minerals 2020, 10(12), 1079; https://doi.org/10.3390/min10121079 - 01 Dec 2020
Cited by 14 | Viewed by 3050
Abstract
Aluminosilicate clay minerals are often a major component of soils and sediments and many of these clays contain structural Fe (e.g., smectites and illites). Structural Fe(III) in smectite clays is redox active and can be reduced to Fe(II) by biotic and abiotic processes. [...] Read more.
Aluminosilicate clay minerals are often a major component of soils and sediments and many of these clays contain structural Fe (e.g., smectites and illites). Structural Fe(III) in smectite clays is redox active and can be reduced to Fe(II) by biotic and abiotic processes. Fe(II)-bearing minerals such as magnetite and green rust can reduce Hg(II) to Hg(0); however, the ability of other environmentally relevant Fe(II) phases, such as structural Fe(II) in smectite clays, to reduce Hg(II) is largely undetermined. We conducted experiments examining the potential for reduction of Hg(II) by smectite clay minerals containing 0–25 wt% Fe. Fe(III) in the clays (SYn-1 synthetic mica-montmorillonite, SWy-2 montmorillonite, NAu-1 and NAu-2 nontronite, and a nontronite from Cheney, Washington (CWN)) was reduced to Fe(II) using the citrate-bicarbonate-dithionite method. Experiments were initiated by adding 500 µM Hg(II) to reduced clay suspensions (4 g clay L−1) buffered at pH 7.2 in 20 mM 3-morpholinopropane-1-sulfonic acid (MOPS). The potential for Hg(II) reduction in the presence of chloride (0–10 mM) and at pH 5–9 was examined in the presence of reduced NAu-1. Analysis of the samples by Hg LIII-edge X-ray absorption fine structure (XAFS) spectroscopy indicated little to no reduction of Hg(II) by SYn-1 (0% Fe), while reduction of Hg(II) to Hg(0) was observed in the presence of reduced SWy-2, NAu-1, NAu-2, and CWN (2.8–24.8% Fe). Hg(II) was reduced to Hg(0) by NAu-1 at all pH and chloride concentrations examined. These results suggest that Fe(II)-bearing smectite clays may contribute to Hg(II) reduction in suboxic/anoxic soils and sediments. Full article
(This article belongs to the Special Issue Redox Reactivity of Iron Minerals in the Geosphere)
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21 pages, 9014 KiB  
Article
Geochemistry of Groundwater and Naturally Occurring Biogenic Pyrite in the Holocene Fluvial Aquifers in Uphapee Watershed, Macon County, Alabama
by Md Mahfujur Rahman, Ming-Kuo Lee and Ashraf Uddin
Minerals 2020, 10(10), 912; https://doi.org/10.3390/min10100912 - 15 Oct 2020
Cited by 1 | Viewed by 2916
Abstract
Naturally occurring biogenic pyrite has been found in Holocene fluvial aquifers in the Uphapee watershed, Macon County, Alabama. The electron microprobe (EMP) analysis showed that the pyrite grains contain 0.20–0.92 weight% of arsenic (As). The scanning electron microscope and energy dispersive spectroscopy (SEM-EDS) [...] Read more.
Naturally occurring biogenic pyrite has been found in Holocene fluvial aquifers in the Uphapee watershed, Macon County, Alabama. The electron microprobe (EMP) analysis showed that the pyrite grains contain 0.20–0.92 weight% of arsenic (As). The scanning electron microscope and energy dispersive spectroscopy (SEM-EDS) analysis confirmed a similar concentration of As in the pyrite that was consistent with the EMP analysis. The SEM analysis also confirmed the presence of additional trace elements such as cobalt (0.19 wt.%), and nickel (0.15 wt.%), indicative of pyrite’s capacity to sequester As and other trace elements. Pyrite grains were naturally formed and developed as large (20–200 μm) euhedral (i.e., cube, octahedron) crystals and non-framboid aggregates. However, the inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the As concentration in the groundwater was not high, and it was within the EPA drinking water standard for As (10 µg/L). These results indicate that dissolved As is sequestered in naturally formed pyrite found in the fluvial sediments. The groundwater was moderately reducing to slightly oxidizing (Eh = 46 to173 mV), and nearly neutral to slightly acidic (pH = 5.53 to 6.51). Groundwater geochemistry data indicated a redox sequence of oxidation, denitrification, Mn(IV) reduction, Fe(III) reduction, and sulfate reduction along the flow path in the fluvial aquifer. The downgradient increases in dissolved Mn and then Fe concentrations reflect increased Mn(II) and Fe(II) production via microbial competition as the aquifer becomes progressively more reduced. Bacterial sulfate reduction seems to dominate near the end of the groundwater flow path, as the availability of Mn- and Fe-oxyhydroxides becomes limited in sediments rich in lignitic wood where increasing sulfate reduction leads to the formation of biogenic pyrite. The groundwater is a Ca-SO4 type and is not SO4 limited; thus, sulfate may serve as an electron acceptor for the bacterial sulfate-reducing reactions that sequester As into pyrite, which in turn results in very low groundwater As concentration (<2 µg/L). Full article
(This article belongs to the Special Issue Redox Reactivity of Iron Minerals in the Geosphere)
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17 pages, 3633 KiB  
Article
Biogenic Fe(II-III) Hydroxycarbonate Green Rust Enhances Nitrate Removal and Decreases Ammonium Selectivity during Heterotrophic Denitrification
by Georges Ona-Nguema, Delphine Guerbois, Céline Pallud, Jessica Brest, Mustapha Abdelmoula and Guillaume Morin
Minerals 2020, 10(9), 818; https://doi.org/10.3390/min10090818 - 16 Sep 2020
Cited by 7 | Viewed by 2572
Abstract
Nitrification-denitrification is the most widely used nitrogen removal process in wastewater treatment. However, this process can lead to undesirable nitrite accumulation and subsequent ammonium production. Biogenic Fe(II-III) hydroxycarbonate green rust has recently emerged as a candidate to reduce nitrite without ammonium production under [...] Read more.
Nitrification-denitrification is the most widely used nitrogen removal process in wastewater treatment. However, this process can lead to undesirable nitrite accumulation and subsequent ammonium production. Biogenic Fe(II-III) hydroxycarbonate green rust has recently emerged as a candidate to reduce nitrite without ammonium production under abiotic conditions. The present study investigated whether biogenic iron(II-III) hydroxycarbonate green rust could also reduce nitrite to gaseous nitrogen during bacterial nitrate reduction. Our results showed that biogenic iron(II-III) hydroxycarbonate green rust could efficiently decrease the selectivity of the reaction towards ammonium during heterotrophic nitrate reduction by native wastewater-denitrifying bacteria and by three different species of Shewanella: S. putrefaciens ATCC 12099, S. putrefaciens ATCC 8071 and S. oneidensis MR-1. Indeed, in the absence of biogenic hydroxycarbonate green rust, bacterial reduction of nitrate converted 11–42% of the initial nitrate into ammonium, but this value dropped to 1–28% in the presence of biogenic hydroxycarbonate green rust. Additionally, nitrite accumulation did not exceed the 2–13% in the presence of biogenic hydroxycarbonate green rust, versus 0–28% in its absence. Based on those results that enhance the extent of denitrification of about 60%, the study proposes a water treatment process that couples the bacterial nitrite production with the abiotic nitrite reduction by biogenic green rust. Full article
(This article belongs to the Special Issue Redox Reactivity of Iron Minerals in the Geosphere)
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