Chemical oxidation of selenite to selenate: Evaluation of reactive oxygen species and O transfer pathways

Paydary, Pooya; Schellenger, Alexandra E. P.; Teli, M. T.; Jaisi, Deb P.; Onnis‐Hayden, Annalisa; Larese-Casanova, Philip

doi:10.1016/j.chemgeo.2021.120229

Cited by 9 publications

(3 citation statements)

References 77 publications

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“…Sharmasarkar and Vance (1995) found Se strongly correlated with clay fractions in Powder River Basin overburden formations. Selenium salts readily dissolve, but the dissolution of Se salts may not contribute substantial soluble Se species (e.g., HSeO3 -or SeO4 2-) if selenite is produced given its preference to readily sorb to sediments (Elrashidi et al 1987;Torres et al 2011;Paydary et al 2021). For the weathering of Powder River Basin waste rock, Se can be modeled as the dissolution of Se-containing gypsum [CaSO4].…”

Section: Arsenic and Selenium Sourcesmentioning

confidence: 99%

Kinetic Model Evaluation of Arsenic and Selenium Sources and Mobility in Waste Rock of the Powder River Basin, USA

Langman

2024

Preprint

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Groundwater quality can be impacted through the backfilling of coal pits with waste rock containing new mineral surfaces and transportable particles. Reaction fronts may propagate with the saturation of these backfill aquifers as the previously bound minerals and newly created nanomaterials provide additional release of potential contaminants. This study was implemented to identify newly available arsenic and selenium sources and effectively model their release with the weathering of waste rock from the Cordero Rojo Mine in the Powder River Basin, Wyoming. Basic forward models were constructed to replicate the typical modeling scenario for the identified mineral sources of arsenic and selenium in the Powder River Basin overburden—pyrite and gypsum, respectively. The basic forward models were unable to capture the arsenic and selenium trends recorded for leachate from a kinetic column loaded with waste rock from the Cordero Rojo Mine. Enhanced models were constructed to capture nanomaterial contributions to supplement the initially identified processes of the oxidation of arsenic-bearing pyrite and dissolution of selenium-bearing gypsum. Incorporation of the nanomaterial contributions produced modeled arsenic and selenium trends similar to the observed trends in the column leachate. The identification and modeling of newly available contaminant sources in backfill waste rock is necessary to predict the exceedance of water quality criteria for overburden formations that have not previously shown the potential for water quality contamination.

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Section: Arsenic and Selenium Sourcesmentioning

confidence: 99%

Kinetic Model Evaluation of Arsenic and Selenium Sources and Mobility in Waste Rock of the Powder River Basin, USA

Langman

2024

Preprint

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“…Such processes are partially responsible for the significant presence of gypsum in Powder River Basin sedimentary formations [59][60][61][62][63]. Se-bearing salts can readily dissolve, but the dissolution of the salts may not contribute substantial soluble Se species (e.g., selenate (SeO 4 2− )) if selenite is produced because of the preference of selenite to readily sorb to sediments [64][65][66]. The Se released into the leachate appears to be primarily particle release (early and large concentrations) with a contribution from Se salt dissolution that is more visible in the second week when the warm-room leachate indicated higher concentrations of Se.…”

Section: Weathering Processes and Solute Trendsmentioning

confidence: 99%

“…The large, early concentrations for Ca and K suggest the release of Ca-and K-bearing nanoparticles [19], desorption (exchangeable ions) from larger particles [79], and/or loss from roughened surfaces [80], followed by a typical slow release of these elements with bulk aluminosilicate weathering [81,82]. Warm-room leachate shows higher initial concentrations than coldroom leachate for both Ca and K, which is the result of temperature and pH controls on desorption and mineral degradation [62][63][64][65][66][67].…”

Section: Bulk Solid Weatheringmentioning

confidence: 99%

Leachate Experiments to Evaluate Weathering of Waste Rock for Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA

Martin,

Langman

2023

Geosciences

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Restoration of open-pit mines may utilize waste rock for landscape reconstruction, which can include the construction of backfill aquifers. Weathering and contaminant transport may be different in backfill aquifers compared to the surrounding aquifer because of newly available mineral surfaces and transportable nano- to micro-scale particles generated during mining. Waste rock from the Cordero Rojo open-pit coal mine in the Powder River Basin was exposed to benchtop leachate experiments for 20 weeks at temperatures of 5 °C and 20 °C. Collected leachate was analyzed for Eh, pH, specific conductance, alkalinity, and cation and anion concentrations as unfiltered and 0.45-μm and 0.2-μm filtered concentrations. During the experiment, leachate Eh and pH substantially varied during the first 55 days, which corresponds to a period of high specific conductance (>1000 µS/cm) and alkalinity (>200 mg/L). Correspondingly, anion and cation concentrations were the largest during this early weathering stage, and the filter fractions indicated multiple forms of transported elements. After this early weathering stage, column leachate evolved towards a weathering equilibrium of neutral, oxidizing, and low solute conditions indicated by positive Eh values, pH near 7, and specific conductance <500 μS/cm. This evolution was reflected in the decline and stabilization or non-detection of metal(loid) concentrations reflective of a shift to primarily bulk aluminosilicate weathering when coal- and salt-associated elements, such as arsenic, cadmium, and selenium, were not detected or at minimal concentrations. Over the course of the experiment, the solute trend of certain elements indicated particular weathering processes—cadmium and nanoparticle transport, selenium and salt dissolution, and arsenic and pyrite oxidation. The mining of overburden formations and use of the waste rock for backfill aquifers as part of landscape reconstruction will create newly available mineral surfaces and nanoparticles that will weather to produce solute concentrations not typically found in groundwater associated with the original overburden.

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Selenite and selenate in clouds at a high-altitude mountain location in central Japan

Kagawa

Katsuta

Ishizaka

2022

Atmospheric Research

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Chemical oxidation of selenite to selenate: Evaluation of reactive oxygen species and O transfer pathways

Cited by 9 publications

References 77 publications

Kinetic Model Evaluation of Arsenic and Selenium Sources and Mobility in Waste Rock of the Powder River Basin, USA

Kinetic Model Evaluation of Arsenic and Selenium Sources and Mobility in Waste Rock of the Powder River Basin, USA

Leachate Experiments to Evaluate Weathering of Waste Rock for Backfill Aquifers in Restored Coal Mine Pits, Powder River Basin, USA

Selenite and selenate in clouds at a high-altitude mountain location in central Japan

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