Reactivity of surface sites on fractured arsenopyrite (FeAsS) toward oxygen

Schaufuß, Andrea G; Nesbitt, H.W.; Scaini, M. J.; Hoechst, H.; Bancroft, Michael; Szargan, R.

doi:10.2138/am-2000-11-1219

Cited by 94 publications

(51 citation statements)

References 35 publications

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“…This is consistent with previous studies, which have identifi ed a range of As-and (or) Fe-rich coatings as arsenopyrite oxidation products (Buckley and Walker 1988;Richardson and Vaughan 1989;Nesbitt et al 1995;Nesbitt and Muir 1998; Schaufuss et al 2000). The main difference between this and previous studies arises from the ability to collect images, chemical analyses, and diffraction data from the same sample at the nanoscale while preserving spatial relationships.…”

Section: Summary Of Resultssupporting

confidence: 90%

“…The geochemistry, hydrogeology, and mineralogy of the Mount Pleasant Mine tailings has been previously presented by Petrunic and Al (2005), and from this study it is evident that elevated As concentrations occur in the near-surface pore water (maximum of 7.1 mg/L). The abiotic and biotic oxidation of arsenopyrite under a variety of conditions (e.g., air and aqueous solutions) has been studied previously (e.g., Buckley and Walker 1988;Richardson and Vaughan 1989;Nesbitt et al 1995;Fernandez et al 1996a, b;Nesbitt and Muir 1998;Schaufuss et al 2000;Jones et al 2003;Mikhlin and Tomashevich 2005). Many of these studies have used spectroscopic techniques to detect changes in oxidation state for As, Fe, and S as arsenopyrite oxidizes and secondary minerals form.…”

Section: Introductionmentioning

confidence: 99%

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Geoscience at the nanometre scale: review of analytical transmission electron microscopy applications

Petrunic

Cavé

et al. 2006

atgeol

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This paper describes applications of analytical Transmission Electron Microscopy (TEM) in the geosciences. The topics include: 1) sulphide-mineral oxidation; 2) trace-metal attenuation by secondary Mn oxides; 3) silicate weathering; 4) transition-metal valence in minerals; and 5) secondary Hg minerals in stream sediments. The main advantage of the analytical TEM is the ability to obtain images, chemical information, and electron diffraction patterns at the nanometre scale. With such high spatial resolution, it is possible to observe physical and chemical features in samples that cannot be resolved with most other techniques. This information can lead to signifi cant improvement in our understanding of the system under investigation. Sample preparation techniques that are used in each study are also described in this paper. The preparation of samples for TEM analysis can be challenging because of the heterogeneity commonly encountered in geological materials, the fragility of some geological samples (e.g., low-temperature minerals), and the need to maintain spatial relationships present in the samples. The sample preparation techniques presented are specifi c to the needs of the study and the appropriateness of these methods is demonstrated by the high quality analytical TEM data that are obtained. RÉSUMÉCet exposé décrit des applications de la microscopie électronique à transmission analytique dans les sciences de la terre. Les aspects étudiés comprennent : 1) l'oxydation des minéraux sulfurés; 2) l'atténuation des métaux-traces par des oxydes de Mn secondaires; 3) la silicatisation météorique; 4) la valence des métaux de transition dans les minéraux; et 5) les minéraux de Hg secondaires dans les sédiments fl uviatiles. Le principal avantage qu'offre la MET analytique est la possibilité d'obtenir des images, des données chimiques et des fi gures de diffraction des électrons à l'échelle nanométrique. Une résolution spatiale aussi élevée permet l'observation dans les échantillons de propriétés physiques et chimiques impossibles à éclaircir au moyen de la majorité des autres techniques. De tels renseignements peuvent mener à une amélioration marquée de notre compréhension du système à l'étude. Cet exposé décrit en plus les techniques de préparation des échantillons utilisées lors de chaque étude. La préparation des échantillons à une analyse MET peut s'avérer compliquée en raison de l'hétérogénéité que présentent communément les matières géologiques, de la fragilité de certains échantillons géologiques (p. ex. minéraux à basse température) et de la néces-sité de maintenir les liens spatiaux présents dans les échantillons. Les techniques de préparation des échantillons présentées sont propres aux besoins de l'étude; les données de haute qualité obtenues des analyses MET témoignent de la pertinence de ces méthodes.

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Section: Summary Of Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Geoscience at the nanometre scale: review of analytical transmission electron microscopy applications

Petrunic

Cavé

et al. 2006

atgeol

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“…During oxidation, As 1− and As 0 on the surfaces of the arsenopyrite initially convert to As 2+ , As 3+ , As 5+ , and possibly As 1+ (Nesbitt, Muir and Pratt, 1995;Schaufuss et al, 2000). Scorodite (FeAsO 4 ·2H 2 O) or amorphous Fe(III) arsenates commonly precipitate from the oxidation of arsenopyrite ( (Krause and Ettel, 1988), 851; (Williams, 2001), 273; (Craw, Falconer and Youngson, 2003), 73; Chapter 3).…”

Section: Arsenosulfides and Arsenian Sulfidesmentioning

confidence: 99%

Arsenic Chemistry

Henke

Hutchison

2009

Arsenic

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“…The Fe2p 3/2 spectrum of pristine arsenopyrite presents one strong peak at 707.26 eV that typically corresponds to Fe(II)-AsS in mineral lattices (Fig. 4a) Nesbitt and Muir 1998;Schaufuss et al 2000). The highenergy tail rising at~709 eV probably reflects the presence of minor Fe(II)-O and/or Fe(III)-AsS and Fe(III)-O contributions, which have been observed for vacuum-fractured surfaces (Schaufuss et al 1998b;Mikhlin and Romanchenko 2007).…”

Section: Surface Analyses Of Pristine and Weathered Arsenopyrite Graimentioning

confidence: 76%

Arsenopyrite weathering under conditions of simulated calcareous soil

Lara¹,

Velázquez²,

Vazquez‐Arenas³

et al. 2015

Environ Sci Pollut Res

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Mining activities release arsenopyrite into calcareous soils where it undergoes weathering generating toxic compounds. The research evaluates the environmental impacts of these processes under semi-alkaline carbonated conditions. Electrochemical (cyclic voltammetry, chronoamperometry, EIS), spectroscopic (Raman, XPS), and microscopic (SEM, AFM, TEM) techniques are combined along with chemical analyses of leachates collected from simulated arsenopyrite weathering to comprehensively examine the interfacial mechanisms. Early oxidation stages enhance mineral reactivity through the formation of surface sulfur phases (e.g., S n (2-)/S(0)) with semiconductor properties, leading to oscillatory mineral reactivity. Subsequent steps entail the generation of intermediate siderite (FeCO3)-like, followed by the formation of low-compact mass sub-micro ferric oxyhydroxides (α, γ-FeOOH) with adsorbed arsenic (mainly As(III), and lower amounts of As(V)). In addition, weathering reactions can be influenced by accessible arsenic resulting in the formation of a symplesite (Fe3(AsO4)3)-like compound which is dependent on the amount of accessible arsenic in the system. It is proposed that arsenic release occurs via diffusion across secondary α, γ-FeOOH structures during arsenopyrite weathering. We suggest weathering mechanisms of arsenopyrite in calcareous soil and environmental implications based on experimental data.

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Reactivity of surface sites on fractured arsenopyrite (FeAsS) toward oxygen

Cited by 94 publications

References 35 publications

Geoscience at the nanometre scale: review of analytical transmission electron microscopy applications

Geoscience at the nanometre scale: review of analytical transmission electron microscopy applications

Arsenic Chemistry

Arsenopyrite weathering under conditions of simulated calcareous soil

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