Abiotic dechlorination in the presence of ferrous minerals

Schaefer, Charles E.; Ho, Paul C.; Berns, Erin; Werth, Charles J.

doi:10.1016/j.jconhyd.2021.103839

Cited by 6 publications

(9 citation statements)

References 38 publications

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“…XRD spectra of the reduced iron minerals prepared under abiotic and biotic conditions were taken (Figure S6); sharp peaks indicate siderite (FeCO 3 ), while broad low peaks and shoulders suggest mackinawite (FeS). Mackinawite was expected to form from Fe and S and can have a weak XRD spectrum; , the siderite formed due to the addition of the bicarbonate buffer, even though FeCO 3 has a much larger solubility constant, K sp , than FeS (3.7 × 10 –11 vs 8.0 × 10 –19 , respectively). , Both mackinawite and siderite have shown reactivity for direct TCE reduction , and for oxygen reduction to create the •OH; , associated reaction rates are generally greater for mackinawite than siderite. The amounts of mackinawite and siderite in this work could not be distinguished, so they are collectively referred to as reduced iron minerals (RIM).…”

Section: Results and Discussionmentioning

confidence: 99%

“…The oxidation–reduction potential (ORP) has been used as a surrogate for iron mineral reactivity with aqueous phase pollutants, , and is used here to determine whether it is related to either •OH production or TCE oxidation. Initial ORP values (i.e., just before O 2 addition) for the different systems are presented in Figure c; they decrease with increasing Fe–S ratios from 1:1 to 50:1.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Hydroxyl radical production has been documented for a suite of reduced iron minerals exposed to O 2 . These include ferrous sulfides like mackinawite and pyrite, ,− ferrous carbonates like siderite and ankerite, iron-containing biotite, and several iron-containing phyllosilicate clays (e.g., montmorillonite, chlorite, illite, and nontronite), ,, with mackinawite generally showing the greatest mass-normalized activity for •OH production. Hydroxyl radical production has also been documented for natural sediments containing reduced iron minerals exposed to O 2.…”

Section: Introductionmentioning

confidence: 99%

“…5,19 In these studies, •OH production increased when sediments were chemically or biologically reduced prior to O 2 exposure, 7,8 and the amount of •OH production was related to the amount of reduced iron in the sediments. 5,7,12,18,19 Minerals implicated in •OH production in the sediments were iron sulfides and iron-containing phyllosilicates. If sulfide is released during iron sulfide mineral oxidation, it can reduce oxidized iron species back to Fe(II), 20 possibly promoting the formation of more reactive iron minerals.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of Hydroxyl Radical Production from Oxygenation of Reduced Iron Minerals and Their Reactivity with Trichloroethene: Effects of Iron Amounts, Iron Species, and Sulfate Reducing Bacteria

You

Liu

Berns-Herrboldt

et al. 2023

Environ. Sci. Technol.

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Reactive oxygen species generated during the oxygenation of different ferrous species have been documented at groundwater field sites, but their effect on pollutant destruction remains an open question. To address this knowledge gap, a kinetic model was developed to probe mechanisms of •OH production and reactivity with trichloroethene (TCE) and competing species in the presence of reduced iron minerals (RIM) and oxygen in batch experiments. RIM slurries were formed by combining different amounts of Fe(II) and sulfide (with Fe(II):S ratios from 1:1 to 50:1) or Fe(II) and sulfate with sulfate reducing bacteria (SRB) added. Extents of TCE oxidation and •OH production were both greater with RIM prepared under more reducing conditions (more added Fe(II)) and then amended with O2. Kinetic rate constants from modeling indicate that •OH production from free Fe(II) dominates •OH production from solid Fe(II) and that TCE competes for •OH with Fe(II) and organic matter (OM). Competition with OM only occurs in experiments with SRB, which include cells and their exudates. Experimental results indicate that cells and/or exudates also provide electron equivalents to reform Fe(II) from oxidized RIM. Our work provides new insights into mechanisms and environmental significance of TCE oxidation by •OH produced from oxygenation of RIM. However, further work is necessary to confirm the relative importance of reaction pathways identified here and to probe potentially unaccounted for mechanisms that affect abiotic TCE oxidation in natural systems.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetics of Hydroxyl Radical Production from Oxygenation of Reduced Iron Minerals and Their Reactivity with Trichloroethene: Effects of Iron Amounts, Iron Species, and Sulfate Reducing Bacteria

You

Liu

Berns-Herrboldt

et al. 2023

Environ. Sci. Technol.

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“…Under anaerobic conditions, the natural attenuation of CEs was observed to be mediated by solid-phase organic substances and reduced minerals . For example, ferrous minerals (e.g., mackinawite, green rust, and pyrite) as essential components involving heterogeneous redox reactions were identified to mediate the abiotic dechlorination of trichloroethene (TCE). − In addition, soil organic matter (SOM) could also affect the fate, mobility, and bioavailability of CEs through adsorption/desorption and other processes . Mechanisms underlying the SOM adsorption of CEs included hydrogen bonding, electrostatic attraction, and pore-filling .…”

Section: Introductionmentioning

confidence: 99%

Reciprocal Interactions of Abiotic and Biotic Dechlorination of Chloroethenes in Soil

Liu,

Zhang,

Shen

et al. 2023

Environ. Sci. Technol.

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Chloroethenes (CEs) as common organic pollutants in soil could be attenuated via abiotic and biotic dechlorination. Nonetheless, information on the key catalyzing matter and their reciprocal interactions remains scarce. In this study, FeS was identified as a major catalyzing matter in soil for the abiotic dechlorination of CEs, and acetylene could be employed as an indicator of the FeS-mediated abiotic CE-dechlorination. Organohalide-respiring bacteria (OHRB)-mediated dechlorination enhanced abiotic CEs-to-acetylene potential by providing dichloroethenes (DCEs) and trichloroethene (TCE) since chlorination extent determined CEs-to-acetylene potential with an order of trans-DCE > cis-DCE > TCE > tetrachloroethene/PCE. In contrast, FeS was shown to inhibit OHRB-mediated dechlorination, inhibition of which could be alleviated by the addition of soil humic substances. Moreover, sulfate-reducing bacteria and fermenting microorganisms affected FeS-mediated abiotic dechlorination by re-generation of FeS and providing short chain fatty acids, respectively. A new scenario was proposed to elucidate major abiotic and biotic processes and their reciprocal interactions in determining the fate of CEs in soil. Our results may guide the sustainable management of CE-contaminated sites by providing insights into interactions of the abiotic and biotic dechlorination in soil.

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Abiotic natural attenuation of 1,2,3-trichloropropane by natural magnetite under O2 perturbation

Gu,

Li,

Zhou

et al. 2024

Chemosphere

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Abiotic dechlorination in the presence of ferrous minerals

Cited by 6 publications

References 38 publications

Kinetics of Hydroxyl Radical Production from Oxygenation of Reduced Iron Minerals and Their Reactivity with Trichloroethene: Effects of Iron Amounts, Iron Species, and Sulfate Reducing Bacteria

Kinetics of Hydroxyl Radical Production from Oxygenation of Reduced Iron Minerals and Their Reactivity with Trichloroethene: Effects of Iron Amounts, Iron Species, and Sulfate Reducing Bacteria

Reciprocal Interactions of Abiotic and Biotic Dechlorination of Chloroethenes in Soil

Abiotic natural attenuation of 1,2,3-trichloropropane by natural magnetite under O2 perturbation

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