Photochemical oxidation of arsenic by oxygen and iron in acidic solutions

Emett, Maree T; Khoe, G. H.

doi:10.1016/s0043-1354(00)00294-3

Cited by 176 publications

(92 citation statements)

References 18 publications

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“…In abiotic conditions, a small and immediate decrease in the concentration of dissolved As(III) but not of As was observed as soon as Fe(II) was added to the medium with or without light (Fig. 2B); this was likely due to the oxidation of As(III) in the presence of oxygen and Fe(II), as previously described (11,15,18,21). The total and rapid removal of dissolved As and of As(III) seen in Fig.…”

Section: Resultssupporting

confidence: 72%

Immobilization of Arsenite and Ferric Iron by Acidithiobacillus ferrooxidans and Its Relevance to Acid Mine Drainage

Duquesne

Lebrun

Casiot

et al. 2003

Appl Environ Microbiol

103

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Weathering of the As-rich pyrite-rich tailings of the abandoned mining site of Carnoulès (southeastern France) results in the formation of acid waters heavily loaded with arsenic. Dissolved arsenic present in the seepage waters precipitates within a few meters from the bottom of the tailing dam in the presence of microorganisms. An Acidithiobacillus ferrooxidans strain, referred to as CC1, was isolated from the effluents. This strain was able to remove arsenic from a defined synthetic medium only when grown on ferrous iron. This A. ferrooxidans strain did not oxidize arsenite to arsenate directly or indirectly. Strain CC1 precipitated arsenic unexpectedly as arsenite but not arsenate, with ferric iron produced by its energy metabolism. Furthermore, arsenite was almost not found adsorbed on jarosite but associated with a poorly ordered schwertmannite. Arsenate is known to efficiently precipitate with ferric iron and sulfate in the form of more or less ordered schwertmannite, depending on the sulfur-to-arsenic ratio. Our data demonstrate that the coprecipitation of arsenite with schwertmannite also appears as a potential mechanism of arsenite removal in heavily contaminated acid waters. The removal of arsenite by coprecipitation with ferric iron appears to be a common property of the A. ferrooxidans species, as such a feature was observed with one private and three collection strains, one of which was the type strain.Weathering of sulfide-rich rocks results in the formation of highly acidic and heavy metal-laden effluents. At the abandoned Pb-Zn mining site of Carnoulès (southeastern France), the pyrite-rich tailings are subject to bioleaching. Consequently, the Reigous spring, which collects the seepage waters from the waste materials, is acid (pH 3) and contains high levels of solubilized metals (Fe, Zn, and Pb) but also extremely high arsenic (As) concentrations (250 mg liter Ϫ1 on average) (26, 27). The extremely high contents of this metalloid are lowered by 2 to 3 orders of magnitude between the bottom of the tailing dam and few hundred meters downstream. The presence in the sediments of bacteria coated with Fe-As-rich material suggested that arsenic attenuation was due to precipitation mechanisms mediated by microorganisms (24,25,26,27). Among them, Acidithiobacillus ferrooxidans was proposed to be involved in the removal of soluble arsenic (9,26,27,35). The role of microorganisms in arsenic attenuation in this ecosystem was evaluated by two different approaches: (i) an A. ferrooxidans strain was isolated from the effluent and its role in arsenic oxidation and/or precipitation was determined (this paper); (ii) arsenite oxidizing bacteria, one of which belongs to the Thiomonas genus, were isolated and characterized (K. Duquesne, A. Yarzabal, J. Ratouchniak, D. Muller, D. Lièvre-mont, M-C. Lett, and V. Bonnefoy, unpublished results).A. ferrooxidans is an acidophilic chemolithoautotrophic gram-negative bacterium commonly encountered in acid mine drainage. This bacterium is resistant to heavy metals and metallo...

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Section: Resultssupporting

confidence: 72%

Immobilization of Arsenite and Ferric Iron by Acidithiobacillus ferrooxidans and Its Relevance to Acid Mine Drainage

Duquesne

Lebrun

Casiot

et al. 2003

Appl Environ Microbiol

103

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“…Water in the stilling pond has a residence time of approximately 2-3 d under the dredging conditions during this study, and contains dissolved organic carbon and suspended iron phases which are photoactive (Khoe et al, 2000;Emett and Khoe, 2001). These compounds can photoreduce, thereby creating hydroxyl radicals and other oxidant species which could oxidize selenium species to selenate in a manner similar to that previously reported for arsenic (Hall et al, 1999;Khoe et al, 2000;Emett and Khoe, 2001;Hug et al, 2001;Bednar et al, 2003). Although this hypothesis is based on a single field collected sample, it remains an active area of investigation for this system.…”

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Geochemical investigations of metals release from submerged coal fly ash using extended elutriate tests

Bednar¹,

Chappell²,

Seiter³

et al. 2010

Chemosphere

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a b s t r a c tA storage pond dike failure occurred at the Tennessee Valley Authority Kingston Fossil Plant that resulted in the release of over 3.8 million cubic meters (5 million cubic yards) of fly ash. Approximately half of this material deposited in the main channel of the Emory River, 3.5 km upstream of the confluence of the Emory and Clinch Rivers, Tennessee, USA. Remediation efforts to date have focused on targeted removal of material from the channel through hydraulic dredging, as well as mechanical excavation in some areas. The agitation of the submerged fly ash during hydraulic dredging introduces river water into the fly ash material, which could alter the redox state of metals present in the fly ash and thereby change their sorption and mobility properties. A series of extended elutriate tests were used to determine the concentration and speciation of metals released from fly ash. Results indicated that arsenic and selenium species released from the fly ash materials during elutriate preparation were redox stable over the course of 10 d, with dissolved arsenic being present as arsenate, and dissolved selenium being present as selenite. Concentrations of certain metals, such as arsenic, selenium, vanadium, and barium, increased in the elutriate waters over the 10 d study, whereas manganese concentrations decreased, likely due to oxidation and precipitation reactions.Published by Elsevier Ltd.

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“…Oxidizing reagents for As(III) (chlorine, ozone, permanganate, and manganese oxide) recommended by USEPA can complete the oxidation within a minute or two [14]. According to the investigation of oxidation of As(III) in low pH solutions by photo-Fenton reactions with dissolved Fe(III) and illumination with near-UV light, Fe(III)-chloride and Fe(III)-hydroxide produced hydroxyl and di-chloro radicals that oxidized As(III) to As(V) [15]. The initial As(III) oxidation rate was increased with the Fe(III) concentration from 0.14 and 0.97 mg/L/min in the solution containing Fe(III) ranging between 50 mg/L and 800 mg/L (As(III) concentration 150 mg/L).…”

Section: A Background Of Our Researchmentioning

confidence: 99%

Monitoring of Arsenite Sorption to Biogenic Iron Oxide in a Flow-Through Column by X-Ray Absorption Spectroscopy

Fujikawa

Sugahara

Honma

et al. 2015

e-J. Surf. Sci. Nanotech.

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We have conducted a pilot study of a biological filtration (BF) system for low-cost arsenic (As) removal from groundwater containing both ferrous iron (Fe(II)) and arsenic (As). Throughout the study, we have observed that arsenite (As(III)) as well as arsenate (As(V)) could be removed with this system. In conventional water treatment technologies, the preoxidation of As(III) to As(V) by oxidizing chemical is a mandatory step for As(III) removal However, such a preoxidation unit has not been used in our BF pilot unit, and hence the mechanisms of As(III) removal by BF have been of interest. Using a flow-through column reactor that simulates the actual BF pond for analysis by X-ray absorption spectroscopy (XAS), we could observe the adsorption of As(III) in water onto iron hydroxides deposited on the biological filter. The time-resolved As K-edge X-ray absorption near-edge structure (XANES) spectra were obtained when the water containing As(III) and Fe(II) was continuously fed to the reactor. An increase in the absorption intensity of the X-ray with time was clearly observed in the time-resolved spectra, indicating that the spectra represented the concentration and chemical state of As adsorbed at the solid-liquid interface of the biological filter. The XAS results also show that while the original water fed to the reactor was supposed to contain only As(III) and Fe(II), a small portion of As(III) was oxidized to As(V) in the influent line when the As(III) solution met the Fe(II) solution before flowing into the reactor. Consequently, besides As(III), As(V) probably formed by the oxidation of As(III) in the influent, was detected on the filter by XAS. The results demonstrate that, in BF, mechanisms of As(III) removal are at least partially explained by the adsorption of As(III) in the raw water to the biological filter as it is.

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Photochemical oxidation of arsenic by oxygen and iron in acidic solutions

Cited by 176 publications

References 18 publications

Immobilization of Arsenite and Ferric Iron by Acidithiobacillus ferrooxidans and Its Relevance to Acid Mine Drainage

Immobilization of Arsenite and Ferric Iron by Acidithiobacillus ferrooxidans and Its Relevance to Acid Mine Drainage

Geochemical investigations of metals release from submerged coal fly ash using extended elutriate tests

Monitoring of Arsenite Sorption to Biogenic Iron Oxide in a Flow-Through Column by X-Ray Absorption Spectroscopy

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