Spectroscopic Investigation of the Uptake of Arsenite from Solution by Synthetic Mackinawite

Gallegos, Tanya J.; Hyun, Sung Pil; Hayes, Kim F.

doi:10.1021/es070613c

Cited by 93 publications

(95 citation statements)

References 34 publications

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“…This result is in contrast to what has been reported for As(III) removal by troilite (FeS), where higher removals occurred above pH 5 and very little As(III) was removed below pH 5 (Wang, et al, 2009). However, experiments on As(III) sorption by synthetic mackinawite (FeS) that were performed by Gallegos (2007), showed a comparable sorption trend with our results. The difference in As(III) sorption edges may be caused by higher solubility of synthetic mackinawite than troilite (Gallegos, 2007).…”

Section: Arsenic(iii) Removal and Stabilitysupporting

confidence: 88%

“…However, experiments on As(III) sorption by synthetic mackinawite (FeS) that were performed by Gallegos (2007), showed a comparable sorption trend with our results. The difference in As(III) sorption edges may be caused by higher solubility of synthetic mackinawite than troilite (Gallegos, 2007). At low pH, the dissolved sulfide from mackinawite can react with soluble As(III) to form As-S precipitates, resulting in higher As(III) removal.…”

Section: Arsenic(iii) Removal and Stabilitysupporting

confidence: 88%

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Novel Adsorbent-Reactants for Treatment of Ash and Scrubber Pond Effluents

Batchelor¹,

Han²,

Kim³

2010

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The overall goal of this project was to evaluate the ability of novel adsorbent/reactants to remove specific toxic target chemicals from ash and scrubber pond effluents while producing stable residuals for ultimate disposal. The target chemicals studied were arsenic (As(III) and As(V)), mercury (Hg(II)) and selenium (Se(IV) and Se(VI)). The adsorbent/reactants that were evaluated are iron sulfide (FeS) and pyrite (FeS 2 ). Procedures for measuring concentrations of target compounds and characterizing the surfaces of adsorbent-reactants were developed. Effects of contact time, pH (7, 8, 9, 10) and sulfate concentration (0, 1, 10 mM) on removal of all target compounds on both adsorbent-reactants were determined. Stability tests were conducted to evaluate the extent to which target compounds were released from the adsorbent-reactants when pH changed. Surface characterization was conducted with x-ray photoelectron spectroscopy (XPS) to identify reactions occurring on the surface between the target compounds and surface iron and sulfur. Results indicated that target compounds could be removed by FeS 2 and FeS and that removal was affected by time, pH and surface reactions. Stability of residuals was generally good and appeared to be affected by the extent of surface reactions. Synthesized pyrite and mackinawite appear to have the required characteristics for removing the target compounds from wastewaters from ash ponds and scrubber ponds and producing stable residuals.

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Section: Arsenic(iii) Removal and Stabilitysupporting

confidence: 88%

Section: Arsenic(iii) Removal and Stabilitysupporting

confidence: 88%

Novel Adsorbent-Reactants for Treatment of Ash and Scrubber Pond Effluents

Batchelor¹,

Han²,

Kim³

2010

View full text Add to dashboard Cite

show abstract

“…Furthermore, As(III)-mackinawite interactions led to the formation of an orpiment (As 2 S 3 )-like species during reduction of As(V)-co-precipitated schwertmannite (Burton et al 2013(Burton et al , 2014. The extent and strength of As sorption to Fe sulfides depend on aqueous As speciation (Bostick and Fendorf 2003;Jönsson and Sherman 2008;Couture et al 2013) and iron sulfide mineralogy (Gallegos et al 2007;Jönsson and Sherman 2008;Renock et al 2009;Couture et al 2013). Ultimately, the interactions of these redox transformations determine how sulfate reduction affects As mobility, considering the various sequestration and mobilization processes.…”

Section: Introductionmentioning

confidence: 99%

Arsenic bioavailability to rice plant in paddy soil: influence of microbial sulfate reduction

2015

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Purpose High arsenic (As) mobility in anaerobic paddy soil due to microbial Fe-and As-reducing processes results in As accumulation into rice plants. Sulfur (S) also undergoes microbial reducing processes in the anaerobic paddy soil, while this process interacts with the Fe-and As-reducing processes, forms secondary minerals, and thus influences As mobility in paddy soil. This work was carried out to investigate the role of sulfur and sulfate-reducing bacteria (SRB) in As redox transformation and bioavailability to rice plant in an anaerobic paddy soil. Materials and methods Anaerobic incubation experiments with or without sulfate (SO 4 2− ) and SRB were carried out to monitor S and iron (Fe) dynamics and their relations to As speciation and release to soil solution. Rice cultivation in pot experiment was then carried out to check the SO 4 2− amendment in bioavailability and uptake into rice plants.Results and discussion The inoculation of an enriched SRB community into the sterilized paddy soil increased reduction and release of As to the soil solution after flooding, showing its ability in arsenate (As(V)) as well as SO 4 2− reduction to arsenite (As(III)) and sulfide (S 2− ), respectively. Sulfate addition (2 and 100 mM) into the anaerobic paddy soil increased the reduction of SO 4 2− and ferric iron (Fe 3+ ) and resulted to lower dissolved As in the soil solution, which limited As mobility in the paddy soil. Application of SO 4 2− (100 mg kg −1 ) into paddy soil finally decreased the concentration of dissolved As in the soil solution by 23.5 % and also decreased As content in rice roots and iron plaque by 22.6 and 30.5 %, respectively. Conclusions The results revealed the important role of sulfur and the SRB activity in As speciation and mobility in anaerobic paddy soil, implying a lower As bioavailability to rice plants under sulfur-enriched anaerobic paddy soil, and an efficient way to reduce As accumulation in rice plants by sulfur fertilization in paddy soils.

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“…Markelova et al Applied Geochemistry 91 (2018) 75-88 particle diffusion (Zhang and Stanforth, 2005) or the formation of surface precipitates (Gallegos et al, 2007), such as Ca-arsenate phases (Bothe and Brown, 1999;Raposo et al, 2004). Based on the initial [As] concentration in Exp.…”

Section: Arsenic Abiotic Sequestrationmentioning

confidence: 99%

Speciation dynamics of oxyanion contaminants (As, Sb, Cr) in argillaceous suspensions during oxic-anoxic cycles

Markelova

Couture

Parsons

et al. 2018

Applied Geochemistry

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A B S T R A C TArgillaceous geological formations are considered promising repositories for waste containing inorganic contaminants. However, the sequestration capacity of an argillaceous natural barrier may change as a result of dynamic environmental conditions, in particular changes in redox state. Here, we imposed redox cycles to argillaceous suspensions amended with a mixture of the inorganic contaminants As(V), Sb(V), Cr(VI), by alternating 7-day cycles of sparging with either oxic or anoxic gas mixtures. During the redox cycles, we assessed the relative importance of different contaminant sequestration mechanisms under sterile and non-sterile conditions. The non-sterile experiments were carried out 1) with the argillaceous material as is, that is, containing the native microbial population, 2) with the addition of ethanol as a source of labile organic carbon, and 3) with the addition of both ethanol and a soil microbial inoculum. In order to capture the observed solid-solution partitioning trends, a series of mixed thermodynamic-kinetic models representing the dynamic conditions in the experiments were developed using PHREEQC. Parameter values for processes such as adsorption, which occurred in all experiments, were kept constant across all the simulations. Additional formulations were introduced as needed to account for the microbial detoxification and respiration of the contaminants in the increasing complexity experiments. Abiotic adsorption of As and abiotic reductive precipitation of Cr dominated sequestration of these two contaminants under all experimental conditions, whereas the presence of microorganisms was essential to decrease the aqueous Sb concentration. Once reduced, As(III), Sb(III), and Cr(III) were not reoxidized upon exposure to dissolved O 2 in any of the experiments. Neither the mineralogy nor the native microbiota catalysed contaminant oxidation processes. Thus, kinetically, the reduction of As(V), Sb(V), and Cr(VI) was irreversible over the experimental duration (49 days). The capacity of the argillaceous matrix to reduce and sequester the aqueous contaminants, without subsequent remobilization to the aqueous phase during the oxic periods, supports the use of argillaceous barriers for geologic waste storage.

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Spectroscopic Investigation of the Uptake of Arsenite from Solution by Synthetic Mackinawite

Cited by 93 publications

References 34 publications

Novel Adsorbent-Reactants for Treatment of Ash and Scrubber Pond Effluents

Novel Adsorbent-Reactants for Treatment of Ash and Scrubber Pond Effluents

Arsenic bioavailability to rice plant in paddy soil: influence of microbial sulfate reduction

Speciation dynamics of oxyanion contaminants (As, Sb, Cr) in argillaceous suspensions during oxic-anoxic cycles

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