Journal ArticleDOI
Arsenate and Chromate Retention Mechanisms on Goethite. 1. Surface Structure
TLDR
In this paper, the authors used Extended X-ray absorption fine structure (EXAFS) spectroscopy to deduce the local coordination environment of two environmental contaminants, arsenate and chromate, on the mineral goethite (α-FeOOH).Abstract:
The molecular structure of ions retained on mineral surfaces is needed to accurately model their sorption process and to determine their stability. Extended X-ray absorption fine structure (EXAFS) spectroscopy was used in this study to deduce the local coordination environment of two environmental contaminants, arsenate and chromate, on the mineral goethite (α-FeOOH). Based on the oxyanion−Fe distances, it was concluded that three different surface complexes exist on goethite for both oxyanions: a monodentate complex, a bidentate-binuclear complex, and a bidentate-mononuclear complex. At low surface coverages, the monodentate complex was favored while at higher coverages the bidentate complexes were more prevalentthe bidentate-binuclear complex appears to be in the greatest proportion at these highest surface coverages. Therefore, modeling efforts for chromate or arsenate retention on goethite need to consider a monodentate complex at very low coverages, both the monodentate and bidentate complexes at in...read more
Citations
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Journal ArticleDOI
Removal of arsenic(V) from spent ion exchange brine using a new class of starch-bridged magnetite nanoparticles.
TL;DR: A new class of starch-bridged magnetite nanoparticles were prepared and tested for removal of arsenate from spent IX brine using a low-cost, "green" starch at 0.049% as a stabilizer and as a bridging agent allowing the nanoparticles to flocculate and precipitate while maintaining their high arsenic sorption capacity.
Journal ArticleDOI
Phosphate adsorption on the iron oxyhydroxides goethite (α-FeOOH), akaganeite (β-FeOOH), and lepidocrocite (γ-FeOOH): a 31P NMR Study
TL;DR: In this article, a static spin-echo mapping NMR experiment was conducted to determine how the phosphate anion binds to common soil minerals, including goethite, akaganeite, and lepidocrocite.
Journal ArticleDOI
Solid-phases and desorption processes of arsenic within Bangladesh sediments
Matthew L. Polizzotto,Charles F. Harvey,Guangchao Li,B Badruzzman,A Ali,Matthew Newville,Steven Sutton,Scott Fendorf +7 more
TL;DR: In this paper, the authors used micro-X-ray fluorescence elemental mapping and near-edge structure spectroscopy to detect arsenic-bearing sulfides in the aquifer sediments from a field site in Munshiganj, Bangladesh.
Journal ArticleDOI
Arsenite oxidation by a poorly crystalline manganese-oxide. 2. Results from X-ray absorption spectroscopy and X-ray diffraction.
TL;DR: X-ray absorption spectroscopy and X-ray diffraction data show that Mn(II) sorption on a poorly crystalline hexagonal birnessite (δ-MnO₂) is important in passivation early during reaction with As(III).
Journal ArticleDOI
XAS speciation of arsenic in a hyper-accumulating fern.
TL;DR: The coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyper-accumulating fern were investigated by X-ray absorption spectroscopy and results indicate that arsenic is predominantly accumulated as As(III) in the leaves.
References
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Book
Environmental Chemistry of Soils
TL;DR: In this article, an introduction to modern soil chemistry describes chemical processes in soils in terms of established principles of inorganic, organic, and physical chemistry, providing an understanding of the structure of the solid mineral and organic materials from which soils are formed.
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Iron Oxides in the Laboratory: Preparation and Characterization
Udo Schwertmann,R. M. Cornell +1 more
TL;DR: In this paper, the main aim of the second edition is to present reliable, well-tested, up-to-date methods of synthesizing pure iron oxides, including monodispersed particles, presently of great interest to industry.
Journal ArticleDOI
Theoretical X-ray Absorption Fine Structure Standards
John J. Rehr,John J. Rehr,J. Mustre de Leon,S. I. Zabinsky,S. I. Zabinsky,R. C. Albers,R. C. Albers +6 more
Journal ArticleDOI
Surface chemistry of ferrihydrite: Part 1. EXAFS studies of the geometry of coprecipitated and adsorbed arsenate
TL;DR: In this article, the As and Fe K-edges were collected from samples of two-line ferrihydrite with adsorbed (ADS) and coprecipitated (CPT) arsenate prepared over a range of conditions and arsenate surface coverages.