Surface chemistry and structural properties of mackinawite prepared by reaction of sulfide ions with metallic iron

Mullet, Martine; Boursiquot, Sophie; Abdelmoula, Mustapha; Génin, J.‐M. R.; Ehrhardt, J.J.

doi:10.1016/s0016-7037(01)00805-5

Cited by 227 publications

(194 citation statements)

References 32 publications

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“…The B.E.T. surface area was measured as 66.96 m 2 /g, which is consistent with Wolthers et al [56] The EDS measurements performed on various sized particles showed this FeS yields an approximate Fe : S ratio of 1 (FeS 0.97 ), which is consistent for all size fractions and agrees well with Mullet et al [57].…”

Section: Fes Characterizationsupporting

confidence: 89%

Pertechnetate immobilization with amorphous iron sulfide

Liu

Terry

Jurisson³

2008

Radiochimica Acta

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Section: Fes Characterizationsupporting

confidence: 89%

Pertechnetate immobilization with amorphous iron sulfide

Liu

Terry

Jurisson³

2008

Radiochimica Acta

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“…This behavior indicates that the oxidation process decreased until pH 6, increasing to higher pHs. This is in agreement with the mackinawite surface chemistry (Mullet et al, 2002). There is a lower intensity of the peaks caracteristic of sulfur (S) and lepdocrocite (L), and the highest band intensity characteristic of mackinawite (M) in the XRPD pattern of the FeS-Cys in relation to the XRPD pattern of the FeS.…”

Section: Mackinawite Oxidation -Short Time-scale Experimentssupporting

confidence: 87%

Modification of Mackinawite with L-Cysteine: Synthesis, Characterization, and Implications to Mercury Immobilization in Sediment

Chaves¹,

Valsaraj²,

DeLaune³

et al. 2011

Sediment Transport

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“…Various causes were proposed for the expansion of this spacing relative to the d (001) of crystalline mackinawite, including the incorporation of either water molecules or oxygen between the (001) sheets (Wolthers et al, 2003). X-ray photoelectron spectroscopy studies identified Fe (III), presumably in greigite-like octahedral coordination, both on the surfaces of mackinawite (Mullet et al, 2002) and in poorly crystalline FeS (Herbert et al, 1998). It is tempting to describe the observed few-layer-thick sheets as hydrated sulfide analogs of metal hydroxides; however, SH groups were never detected by spectroscopic analyses of samples that can be regarded equivalent to FeS am (Rickard and Luther, 2007).…”

Section: Structure and Particle Size Of Precipitated Fesmentioning

confidence: 99%

“…For the low-temperature synthesis of iron monosulfide, three approaches are commonly used: reacting sulfide with either (1) metallic iron or (2) a ferrous solution, and (3) by using sulfate-reducing bacteria. In general, method 1 leads to crystalline mackinawite with a stoichiometric composition (Lennie et al, 1995;Mullet et al, 2002), whereas processes 2 and 3 result in either ordered mackinawite (Michel et al, 2005;Benning et al, 2000) or disordered, mackinawite-like phases (termed 'FeS am ' hereinafter) (Wolthers et al, 2003;Shi et al, 2006;Renock et al, 2009;this study). Typically, the XRD patterns of such disordered materials contain a broad peak between~5 and 6 Å, usually interpreted as indicating an expansion along the c axis relative to that of crystalline mackinawite (Herbert et al, 1998;Ohfuji and Rickard, 2006;Jeong et al, 2008) (Table 2).…”

Section: Introductionmentioning

confidence: 99%

Structural properties and transformations of precipitated FeS

et al. 2012

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Editor: J. Fein Keywords:Amorphous iron sulfide Mackinawite Greigite Phase transformations XRD TEM Nanocrystalline iron sulfides form in diverse anoxic environments. The initial precipitate is commonly referred to as nanocrystalline mackinawite (FeS) or amorphous FeS. In order to better understand the structure of the initial precipitate and its conversion to mackinawite and greigite (Fe 3 S 4 ), we studied synthetic iron sulfide samples that were precipitated from hydrous solutions near room temperature. The transformation of precipitated FeS was followed in both aqueous and dry aging experiments using X-ray powder diffraction (XRD) and scanning and transmission electron microscopy (SEM/TEM) and selected-area electron diffraction (SAED). Under tightly controlled anoxic conditions the first precipitate was nanocrystalline mackinawite. In contrast, when anaerobic conditions during synthesis were not completely ensured, freshly precipitated iron sulfide was typically X-ray amorphous (FeS am ), and showed only one broad Bragg-peak at 2Θ = 16.5°(5.4 Å). A distribution of interatomic distances calculated from pair-distribution function analysis of SAED patterns of FeS am showed that only short-range (b 7 Å) order was present in the bulk of the material, with Fe mainly present in tetrahedral coordination. SEM and TEM images confirmed the poorly ordered structure and showed that FeS am formed aggregates of curved, amorphous sheets that contained 3-8 structurally ordered layers at their cores. Such layers are generally assumed to be structurally similar to the tetrahedral iron sulfide layers in mackinawite. However, both inter-and intralayer spacings measured in high-resolution TEM images (~5.3 to 6.3 and~3.0 to 3.1 Å, respectively) were significantly larger than the corresponding spacings in crystalline mackinawite (5.03 and 2.6 Å, respectively), suggesting that short-range structural order within the semi-ordered layers of FeS am was not mackinawite-like. In aqueous aging experiments at room temperature, FeS am transformed into a mixture of mackinawite and greigite in~2 months, and completely converted to platy greigite crystals after~10 months. These aqueous transformations were likely driven by excess sulfur in the reacting solutions. We also studied the conversions of nanocrystalline mackinawite. In order to accelerate phase transitions, the initial FeS precipitate was heated to 120°C, resulting in the formation of crystalline mackinawite within 2 h; at 150°C, the material converted directly to pyrrhotite. Finally, when stored in a dry state at room temperature, crystalline mackinawite converted to greigite in 3 months, much faster than in the equivalent experiments in the aqueous solution, probably as a result of a more oxidative environment. The distinction between FeS am and nanocrystalline mackinawite is significant, since conditions for the formation of both phases are present in natural settings. Our experiments in a well-sealed anaerobic chamber simulate iron sulfide formation under anoxic conditions, where...

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Surface chemistry and structural properties of mackinawite prepared by reaction of sulfide ions with metallic iron

Cited by 227 publications

References 32 publications

Pertechnetate immobilization with amorphous iron sulfide

Pertechnetate immobilization with amorphous iron sulfide

Modification of Mackinawite with L-Cysteine: Synthesis, Characterization, and Implications to Mercury Immobilization in Sediment

Structural properties and transformations of precipitated FeS

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