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
Surface complexation modeling of interactions between freshwater and marine diatom species and trace elements (Mo, W, Cr, Ge, Ga, Al)
Alexandre Gélabert,Oleg S. Pokrovsky,Oleg S. Pokrovsky,Oleg S. Pokrovsky,Jacques Schott,Agnès Feurtet-Mazel +5 more
TL;DR: In this paper, a surface complexation approach was used to identify the functional groups involved in the complexation of trace elements with diatom surface moieties and quantified the stability of surface complexes formed at the diatom solution interface.
Journal ArticleDOI
Performance Evaluation of Fixed Bed of Nano Calcium Oxide Synthesized from a Gastropod Shell (Achatina achatina) in Hexavalent Chromium Abstraction from Aqua System
TL;DR: In this article, the shell of a gastropod (Achatina Achatina) was used as a precursor for the synthesis of nano calcium oxide (NC) via the sol-gel technique.
Journal ArticleDOI
Aminated glycidyl methacrylates as a support media for goethite nanoparticle enabled hybrid sorbents for arsenic removal: From copolymer synthesis to full-scale system modeling
Khaled Taleb,Jasmina Markovski,Jasmina Markovski,Kiril Hristovski,Vladana N. Rajaković-Ognjanović,Antonije Onjia,Aleksandar D. Marinković +6 more
TL;DR: In this paper, a cross-linked macroporous glycidyl methacrylate copolymer support media was developed and tested to achieve short mass transfer zones that enable arsenic removal under high hydraulic loading rates and short empty bed contact times needed for small point-of-use packed bed applications.
Journal ArticleDOI
Adsorption and desorption of arsenic and its immobilization in soils
Cecília Calhau Almeida,Maurício Paulo Ferreira Fontes,Adriana Cristina Dias,Thiago Torres Costa Pereira,João Carlos Ker +4 more
TL;DR: In this paper, the authors assess the adsorption of As(V) in soils from Minas Gerais, Brazil, and determine its immobilization rate in order to identify soils with characteristics more favorable to its deployment as an As geochemical barrier.
Journal ArticleDOI
Trace element geochemistry of iron-(oxy)-hydroxides in Ni(Co)-laterites: Review, new data and implications for ore forming processes
TL;DR: In this paper, the authors investigated the geochemistry of goethite and hematite within the oxidation zone of the respective laterite profiles, evaluating the deportment of minor metals such as Ti, Sc, Cr, Ni, Co, V, Zn, and Mn.
References
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Book
Environmental Chemistry of Soils
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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.