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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Dissertation
Mobilization and natural attenuation of arsenic in acid mine drainage ( AMD )
Asta Andrés,María Pilar +1 more
TL;DR: In this article, the authors study the impact of the mobilitzacio of larsenic alliberat a les aigues depen de la seva atenuacio natural.
Dissertation
The adsorption of arsenic oxyacids to iron oxyhydroxide columns
TL;DR: In this paper, the ionic radius for the sodium ion in six-coordination is derived from structures not representative for aqueous solutions, and the improved larger value is 1.07 A in 6-coordinated crystal structures and increases to 1.09 A due to hydration effects.
Journal ArticleDOI
Arsenite Removal from Aqueous Solution using Mixed Mineral Systems Injected with Iron Sulfide under Sulfidic- Anoxic conditions 1: Reactivity and Removal Kinetics
TL;DR: In this paper, the reactivity and removal kinetics of arsenite treated with single and mixed mineral systems of kaolinite, montmorillonite and goethite injected with iron sulfide under sulfidic-anoxic conditions has been investigated.
Journal ArticleDOI
Improved arsenite adsorption using iron-impregnated marble dust with surface functionalized by quaternary ammonium ions
TL;DR: In this article, marble dust impregnated with iron and functionalized with quaternary ammonium ions [using ammonium persulphate (APS)] was used as a novel adsorbent for the removal of arsenite ions from wastewater.
Journal ArticleDOI
Firing Increases Arsenic Leaching from Ceramic Water Filters via Arsenic and Iron Phase Transformations
TL;DR: In this article, the authors investigate the extent of arsenic leaching from fired and uncalibrated clay and test-fired clay from the United States and Cambodia using X-ray absorption spectra.
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.