Beamline 10.3.2 at ALS: a hard X-ray microprobe for environmental and materials sciences

Marcus, Matthew A.; MacDowell, Alastair A.; Celestre, Richard; Manceau, Alain; Miller, T.; Padmore, H. A.; Sublett, Robert E.

doi:10.1107/s0909049504005837

Cited by 261 publications

(244 citation statements)

References 6 publications

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“…It is known that the predominant U oxidation state is U(VI) in these oxic/suboxic subsurface environments and that U(VI) speciation changes with depth (3). Uranium is released slowly from contaminated 300 Area sediments to percolating waters (4), and information is sought on the mechanisms responsible for the slow kinetics.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Evidence for Uranium Bearing Precipitates in Vadose Zone Sediments at the Hanford 300-Area Site

Arai

Marcus

Tamura

et al. 2007

Environ. Sci. Technol.

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Uranium (U) solid-state speciation in vadose zone sediments collected beneath the former North Process Pond (NPP) in the 300 Area of the Hanford site (Washington) was investigated using multi-scale techniques. In 30 day batch experiments, only a small fraction of total U (∼7.4%) was released to artificial groundwater solutions equilibrated with 1% pCO 2 . Synchrotron-based micro-X-ray fluorescence spectroscopy analyses showed that U was distributed among at least two types of species: (i) U discrete grains associated with Cu and (ii) O) at some U discrete grains, and muscovite at U intermediate concentration areas, were identified in synchrotron-based micro-X-ray diffraction. Scanning electron microscopy/energy dispersive X-ray analyses revealed 8-10 µm size metatorbernite particles that were embedded in C-, Al-, and Si-rich coatings on quartz and albite grains. In µ-and bulk-X-ray absorption structure (µ-XAS and XAS) spectroscopy analyses, the structure of metatorbernite with additional U-C and U-U coordination environments was consistently observed at U discrete grains with high U concentrations. The consistency of the µ-and bulk-XAS analyses suggests that metatorbernite may comprise a significant fraction of the total U in the sample. The entrapped, micrometer-sized metatorbernite particles in C-, Al-, and Si-rich coatings, along with the more soluble precipitated uranyl carbonates and uranophane, likely control the long-term release of U to water associated with the vadose zone sediments.

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Section: Introductionmentioning

confidence: 99%

Spectroscopic Evidence for Uranium Bearing Precipitates in Vadose Zone Sediments at the Hanford 300-Area Site

Arai

Marcus

Tamura

et al. 2007

Environ. Sci. Technol.

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“…Synchrotron l-X-ray fluorescence (l-SXRF) image maps of thin sections were recorded using monochromatic radiation at Advanced Light Source (ALS) beam line 10.3.2 (Marcus et al, 2004). X-ray energy was generally 10 keV.…”

Section: Imagingmentioning

confidence: 99%

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

Bargar

Fuller

Marcus

et al. 2009

Geochimica et Cosmochimica Acta

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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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“…X-ray microanalysis and Cl 1s XANES spectroscopy l-XRF experiments were performed on beamline 10.3.2 (Marcus et al, 2004) at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL, Berkeley, CA, USA). Detection of elements with atomic numbers lower than 18 was enabled using a He-purged air exclusion device fitted with X-ray clean polyfilm windows over the 7-element solid-state Ge detector.…”

Section: Experimental Field Stationmentioning

confidence: 99%

X-ray spectromicroscopic investigation of natural organochlorine distribution in weathering plant material

Leri

Marcus

Myneni

2007

Geochimica et Cosmochimica Acta

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Beamline 10.3.2 at ALS: a hard X-ray microprobe for environmental and materials sciences

Cited by 261 publications

References 6 publications

Spectroscopic Evidence for Uranium Bearing Precipitates in Vadose Zone Sediments at the Hanford 300-Area Site

Spectroscopic Evidence for Uranium Bearing Precipitates in Vadose Zone Sediments at the Hanford 300-Area Site

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

X-ray spectromicroscopic investigation of natural organochlorine distribution in weathering plant material

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