Solubility products of amorphous ferric arsenate and crystalline scorodite (FeAsO4·2H2O) and their application to arsenic behavior in buried mine tailings

Langmuir, Donald; Mahoney, John J.; Rowson, John

doi:10.1016/j.gca.2006.03.006

Cited by 338 publications

(187 citation statements)

References 12 publications

(23 reference statements)

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“…The very low bioaccessibility results for sample GD1 (predominantly scorodite) are consistent with the low solubility of this phase, and cannot be attributed to limited available surface area since the scorodite in this sample is present as micro-to nano-crystalline aggregates (24). Furthermore, the bioaccessible arsenic concentration of 671 mg•kg -1 (0.32%) at the neutral pH of P2, compared to only 277 mg•kg -1 (0.13%) in P1 is consistent with the pH dependent solubility behaviour of pure scorodite (31). In general, the presence of iron arsenates other than scorodite (e.g.…”

Section: )supporting

confidence: 80%

Effects of Soil Composition and Mineralogy on the Bioaccessibility of Arsenic from Tailings and Soil in Gold Mine Districts of Nova Scotia

Meunier

Walker

Wragg

et al. 2010

Environ. Sci. Technol.

179

113

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Bioaccessibility tests and mineralogical analyses were performed on arsenic-contaminated tailings and soils from gold mine districts of Nova Scotia, Canada, to examine the links between soil composition, mineralogy and arsenic bioaccessibility. Arsenic bioaccessibility ranges from 0.1% to 49%. A weak correlation was observed between total and bioaccessible arsenic concentrations, and the arsenic bioaccessibility was not correlated with other elements. Bulk Xray absorption near-edge structure analysis shows arsenic in these near-surface samples is mainly in pentavalent form, indicating that most of the arsenopyrite (As 1-) originally present in the tailings and soils has been oxidized during weathering reactions. Detailed mineralogical analyses of individual samples identified up to seven arsenic species, the relative proportions of which appear to affect arsenic bioaccessibility. The highest arsenic bioaccessibility (up to 49%) is associated with the presence of calcium-iron arsenate. Samples containing arsenic predominantly as arsenopyrite or scorodite have the lowest bioaccessibility (< 1%). Other arsenic species identified (predominantly amorphous iron arsenates and arsenic-bearing iron(oxy)hydroxides) are associated with intermediate bioaccessibility (1 to 10%). The presence of a more soluble arsenic phase, even at low concentrations, results in increased arsenic bioaccessibility from the mixed arsenic phases associated with tailings and mine-impacted soils.3

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Section: )supporting

confidence: 80%

Effects of Soil Composition and Mineralogy on the Bioaccessibility of Arsenic from Tailings and Soil in Gold Mine Districts of Nova Scotia

Meunier

Walker

Wragg

et al. 2010

Environ. Sci. Technol.

179

113

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“…2H 2 O) appear to be the most effective compounds for the immobilization or disposal of As. Thus far, several studies have been conducted on the solubility and stability of ferric arsenate compounds in water [1][2][3][4][5] and on the dissolution of As from ferric arsenate compounds. [5][6][7] Fundamental studies on E-pH diagrams of arsenic relevant systems 8) and experimental studies on adsorption characteristics of arsenate on ferric compounds [9][10][11][12][13][14][15] have also been conducted.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, it has been reported that different solubilities of As were obtained for different scorodite particles. 1,4) In order to synthesize stable ferric arsenate compounds, precipitation processes of scorodite in water have been investigated by examining the precipitates and analyzing the solution. [16][17][18][19] In these studies, scorodite particles were precipitated by reacting Fe(III) with As(V) in water; it should be noted that the solution conditions in these studies were different in each study.…”

Section: Introductionmentioning

confidence: 99%

Coprecipitation of Large Scorodite Particles from Aqueous Fe(II) and As(V) Solution by Oxygen Injection

Shinoda

Tanno

Fujita³

et al. 2009

Mater. Trans.

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A novel method for synthesizing large scorodite (FeAsO 4 . 2H 2 O) particles was recently developed for the fixation of arsenic. This method involves the coprecipitation of scorodite particles from an Fe(II) and As(V) aqueous solution at approximately 95 C by oxygen injection. In order to understand the process of coprecipitation of scorodite particles by this method, X-ray diffractometry (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used for characterizing reaction products extracted from the suspension during the reaction. The SEM observation showed that the formation of large scorodite particles was almost completed after a reaction time of 3 h, and then, fine particles precipitated on the large particles by further reactions. The XRD results indicated that scorodite particles with specific lattice parameters were formed in the reaction. The XPS results indicated that the arsenic composition on the surface of the scorodite particles decreased until 3 h from the start of precipitation reaction and increased thereafter. These results correspond to the results on the morphology of the scorodite particles obtained by SEM. Furthermore, X-ray absorption spectra (XAS) in the range of X-ray absorption near edge structure (XANES) were measured for gel-like reaction products formed in the initial stages of the reaction. The spectra revealed that the gel-like reaction products were composed of Fe(II) and Fe(III). The coprecipitation of scorodite particles synthesized by the novel method is discussed on the basis of these results together with previous results on the analyses of iron and arsenic concentrations in solution.

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“…Consequently, it was assumed that any As released into the soil pore water will be present as As(V). The co-release of ferrihydrite during scorodite dissolution has been shown to reduce As(V) concentrations in pore waters due to adsorption onto the Fe oxide surface [53]. Due to this and the possibility of arsenate immobilization by other sorbates in soil, electron probe microanalysis (EPMA) was used to visually determine, based on elemental mapping, the chemical association of As on the surface of the with the binary oxide waste.…”

Section: Binary Oxide Waste Lysimeter Trialmentioning

confidence: 99%

In situ arsenic oxidation and sorption by a Fe-Mn binary oxide waste in soil

McCann

Peacock

Hudson‐Edwards

et al. 2018

Journal of Hazardous Materials

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In situ arsenic oxidation and sorption by a Fe-Mn binary oxide waste in soil., Journal of Hazardous Materialshttp://dx.doi.org/10. 1016/j.jhazmat.2017.08.066 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Graphical abstractHighlights  A Fe-Mn binary oxide waste is used to remediate As contaminated soils. As(III) and As(V) adsorption capacities of 70 mg g 1 and 32 mg g 1 were determined. The bioaccessibility of total As was significantly reduced by 7.80 %  Arsenic in the contaminated soil effectively binds to the exogenous binary oxide. As(V) was sorbed by mononuclear bidentate corner-sharing with Fe. AbstractThe ability of a Fe-Mn binary oxide waste to adsorb arsenic (As) in a historically contaminated soil was investigated. Initial laboratory sorption experiments indicated that arsenite [As(III)] was oxidized to arsenate [As(V)] by the Mn oxide component, with concurrent As(V) sorption to the Fe oxide. The binary oxide waste had As(III) and As(V) adsorption capacities of 70 mg g 1 and 32 mg g 1 respectively. X-ray Absorption Near-Edge Structure and Extended X-ray Absorption Fine Structure at the As K-edge confirmed that all binary oxide waste surface complexes were As(V) sorbed by 3 mononuclear bidentate corner-sharing, with 2 Fe at ~ 3.27 Ǻ The ability of the waste to perform this coupled oxidation-sorption reaction in real soils was investigated with a 10% by weight addition of the waste to an industrially As contaminated soil. Electron probe microanalysis showed As accumulation onto the Fe oxide component of the binary oxide waste, which had no As innately. The bioaccessibility of As was also significantly reduced by 7.80 % (p < 0.01) with binary oxide waste addition. The results indicate that Fe-Mn binary oxide wastes could provide a potential in situ remediation strategy for As and Pb immobilization in contaminated soils.

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Solubility products of amorphous ferric arsenate and crystalline scorodite (FeAsO4·2H2O) and their application to arsenic behavior in buried mine tailings

Cited by 338 publications

References 12 publications

Effects of Soil Composition and Mineralogy on the Bioaccessibility of Arsenic from Tailings and Soil in Gold Mine Districts of Nova Scotia

Effects of Soil Composition and Mineralogy on the Bioaccessibility of Arsenic from Tailings and Soil in Gold Mine Districts of Nova Scotia

Coprecipitation of Large Scorodite Particles from Aqueous Fe(II) and As(V) Solution by Oxygen Injection

In situ arsenic oxidation and sorption by a Fe-Mn binary oxide waste in soil

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