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
Interaction of Chromium(VI) with the α-Aluminum Oxide−Water Interface
TL;DR: In this article, the authors apply resonantly enhanced second harmonic generation as well as the χ(3) to control the transport, speciation, and ultimate fate of aqueous pollutants in groundwater.
Journal ArticleDOI
Arsenic Occurrence, Mobility, and Retardation in Sandstone and Dolomite Formations of the Fox River Valley, Eastern Wisconsin
Katie Thornburg,Nita Sahai +1 more
TL;DR: Results indicate that arsenic is present in isomorphous substitution with pyrite/marcasite (FeS2), which occurs as disseminated veins, grains, and nodules in the dolomite and sandstone, and elevated As levels observed in eastern Wisconsin groundwater are attributed to differences in the type of sulfide occurrence.
Journal ArticleDOI
Effects of pH, competing ions and aging on arsenic(V) sorption and isotopic exchange in contaminated soils
M.S. Rahman,Malcolm W Clark,Lachlan H Yee,M.J. Comarmond,Timothy E. Payne,Timothy E. Payne,Edward D Burton +6 more
TL;DR: In this paper, As(V)-sorption and accessibility in three As-contaminated soils and two uncontaminated soil types (ferralitic and sandy soils) were investigated utilizing batch sorption experiments and isotopic exchange techniques.
Journal ArticleDOI
Iron incorporated rice husk silica as a sorbent for hexavalent chromium attenuation in aqueous system
Nurudeen A. Oladoja,Isaac Ayodele Ololade,Oyekunle Azeez Alimi,Thompson A. Akinnifesi,G.A. Olaremu +4 more
TL;DR: In this paper, an environmentally benign metal oxide, Fe, was incorporated into silica derived from rice husk via the sol gel route and the physiognomies of both the modified (IRS) and raw Rice husk derived silica (RHS) were studied via FTIR and XRD analysis and pH PZC and surface area determinations.
Book ChapterDOI
Adsorption of phosphate on variable charge minerals and soils as affected by organic and inorganic ligands.
TL;DR: The competitive adsorption of phosphate and organic ligands (e.g., oxalate, tartrate, malate, citrate) is influenced by pH, the nature of the ligands, and the surface of clay minerals and soils.
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.
Book
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.