Structure of heavy-metal sorbed birnessite: Part 1. Results from X-ray diffraction

Lanson, Bruno; Drits, Victor A.; Gaillot, Anne-Claire; Silvester, Ewen; Plançon, A.; Manceau, Alain

doi:10.2138/am-2002-11-1213

Cited by 124 publications

(138 citation statements)

References 61 publications

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“…Since the structure is turbostratic, the periodicity is only two-dimensional and the XRD patterns have no hkl reflections (Warren 1941). Thus, three-dimensional unit-cell parameters and space groups cannot be defined, and structure models can be determined only by modeling the scattered X-ray intensity to theoretical models, as described previously Drits et al 1998;Lanson et al 2000Lanson et al , 2002aLanson et al , 2002bLanson et al , 2008Gaillot et al 2004Gaillot et al , 2005Villalobos et al 2006;Grangeon et al 2008). The sensitivity of XRD to structural parameters, including the size of coherent scattering domains (CSD sizes), a and b lattice parameters, atomic positions, and site occupancies has been discussed elsewhere Villalobos et al 2006;Grangeon et al 2008;Lanson et al 2008).…”

Section: X-ray Diffractionmentioning

confidence: 99%

Structure of nanocrystalline phyllomanganates produced by freshwater fungi

Grangeon

Lanson

Miyata

et al. 2010

American Mineralogist

145

134

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The crystal structures of biogenic Mn oxides produced by three fungal strains isolated from stream pebbles were determined using chemical analyses, XANES and EXAFS spectroscopy, and powder X-ray diffraction. The fungi-mediated oxidation of aqueous Mn 2+ produces layered Mn oxides analogous to vernadite, a natural nanostructured and turbostratic variety of birnessite. The crystallites have domain dimensions of ~10 nm in the layer plane (equivalent to ~35 MnO 6 octahedra), and ~1.5-2.2 nm perpendicularly (equivalent to ~2-3 layers), on average. The layers have hexagonal symmetry and from 22 to 30% vacant octahedral sites. This proportion likely includes edge sites, given the extremely small lateral size of the layers. The layer charge deficit, resulting from the missing layer Mn 4+ cations, is balanced mainly by interlayer Mn 3+ cations in triple-corner sharing position above and/or below vacant layer octahedra. The high surface area, defective crystal structure, and mixed Mn valence confer to these bio-minerals an extremely high chemical reactivity. They serve in the environment as sorption substrate for trace elements and possess catalytic redox properties.

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Section: X-ray Diffractionmentioning

confidence: 99%

Structure of nanocrystalline phyllomanganates produced by freshwater fungi

Grangeon

Lanson

Miyata

et al. 2010

American Mineralogist

145

134

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“…The present study helps to explain the sorptive capacity of the Mn oxide coatings. Bacteriogenic and abiotic layered Mn oxides have impressive sorptive capacity for a range of metals, with edge sites and Mn(IV) vacancy sites being particularly important for contaminant metal binding (Nelson et al, 1999;Lanson et al, 2002b;O'Reilly and Hochella, 2003;Tebo et al, 2004;Villalobos et al, 2005a,b;Toner et al, 2006;Webb et al, 2006). The nanosheet morphology and abundant Mn(IV) vacancies of the Pinal Creek hyporheic zone Mn oxides should bequeath them with a great abundance of metal-binding sites.…”

Section: Comparison To Laboratory Bacteriogenic Mn Oxidesmentioning

confidence: 99%

Structural characterization of terrestrial microbial Mn oxides from Pinal Creek, AZ

Bargar

Fuller

Marcus

et al. 2009

Geochimica et Cosmochimica Acta

110

106

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The microbial catalysis of Mn(II) oxidation is believed to be a dominant source of abundant sorption-and redox-active Mn oxides in marine, freshwater, and subsurface aquatic environments. In spite of their importance, environmental oxides of known biogenic origin have generally not been characterized in detail from a structural perspective. Hyporheic zone Mn oxide grain coatings at Pinal Creek, Arizona, a metals-contaminated stream, have been identified as being dominantly microbial in origin and are well studied from bulk chemistry and contaminant hydrology perspectives. This site thus presents an excellent opportunity to study the structures of terrestrial microbial Mn oxides in detail. XRD and EXAFS measurements performed in this study indicate that the hydrated Pinal Creek Mn oxide grain coatings are layer-type Mn oxides with dominantly hexagonal or pseudo-hexagonal layer symmetry. XRD and TEM measurements suggest the oxides to be nanoparticulate plates with average dimensions on the order of 11 nm thick Â 35 nm diameter, but with individual particles exhibiting thickness as small as a single layer and sheets as wide as 500 nm. The hydrated oxides exhibit a 10-Å basal-plane spacing and turbostratic disorder. EXAFS analyses suggest the oxides contain layer Mn(IV) site vacancy defects, and layer Mn(III) is inferred to be present, as deduced from Jahn-Teller distortion of the local structure. The physical geometry and structural details of the coatings suggest formation within microbial biofilms. The biogenic Mn oxides are stable with respect to transformation into thermodynamically more stable phases over a time scale of at least 5 months. The nanoparticulate layered structural motif, also observed in pure culture laboratory studies, appears to be characteristic of biogenic Mn oxides and may explain the common occurrence of this mineral habit in soils and sediments.

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“…At high Pb loading, another interlayer adsorbed species, a triple edge-sharing (TES) surface complex (Fig. 1b), has been identified, wherein Pb(II) binds to two O II and the one surface O (O III ) that is triply-coordinated to Mn near the tridentate cavity created by three edge-sharing Mn octahedra Lanson et al, 2002;Manceau et al, 2002). The Pb-TES variant with Pb(II) positioned near the vacancy Grangeon et al, 2008) is regarded as more stable than the corresponding alternative surface complex with Pb(II) bonded to three O III , which is similar to the local Pb(II) coordination environment in the Pb-Mn oxyhydroxide mineral, quenselite [PbMnO 2 OH (Rouse, 1971)].…”

Section: Introductionmentioning

confidence: 99%

Surface complexation of Pb(II) by hexagonal birnessite nanoparticles

Kwon

Refson

Sposito

2010

Geochimica et Cosmochimica Acta

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Natural hexagonal birnessite is a poorly-crystalline layer type Mn(IV) oxide precipitated by bacteria and fungi which has a particularly high adsorption affinity for Pb(II). X-ray spectroscopic studies have shown that Pb(II) forms strong inner-sphere surface complexes mainly at two sites on hexagonal birnessite nanoparticles: triple corner-sharing (TCS) complexes on Mn(IV) vacancies in the interlayers and double edge-sharing (DES) complexes on lateral edge surfaces. Although the TCS surface complex has been well characterized by spectroscopy, some important questions remain about the structure and stability of the complexes occurring on the edge surfaces. First-principles simulation techniques such as density functional theory (DFT) offer a useful way to address these questions by providing complementary information that is difficult to obtain by spectroscopy. Following this computational approach, we used spinpolarized DFT to perform total-energy-minimization geometry optimizations of several possible Pb(II) surface complexes on model birnessite nanoparticles similar to those that have been studied experimentally. We first validated our DFT calculations by geometry optimizations of (1) the Pb-Mn oxyhydroxide mineral, quenselite (PbMnO 2 OH), and (2) the TCS surface complex, finding good agreement with experimental structural data while uncovering new information about bonding and stability. Our geometry optimizations of several protonated variants of the DES surface complex led us to conclude that the observed edge-surface species is very likely to be this complex if the singly-coordinated terminal O that binds to Pb(II) is protonated. Our geometry optimizations also revealed that an unhydrated double corner-sharing (DCS) species that has been proposed as an alternative to the DES complex is intrinsically unstable on nanoparticle edge surfaces, but could become stabilized if the local coordination environment is 3 well-hydrated. A significant similarity exists in the structural parameters for the TCS complex and those for a DCS edge-surface complex that is protonated in the same manner as the optimal DES complex, which could complicate detecting the DCS complex in X-ray absorption spectra.4

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Structure of heavy-metal sorbed birnessite: Part 1. Results from X-ray diffraction

Cited by 124 publications

References 61 publications

Structure of nanocrystalline phyllomanganates produced by freshwater fungi

Structure of nanocrystalline phyllomanganates produced by freshwater fungi

Structural characterization of terrestrial microbial Mn oxides from Pinal Creek, AZ

Surface complexation of Pb(II) by hexagonal birnessite nanoparticles

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