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Title: Sb(III) and Sb(V) Sorption onto Al-Rich Phases: Hydrous Al Oxide and the Clay Minerals Kaolinite KGa-1b and Oxidized and Reduced Nontronite NAu-1

Abstract

We have studied the immobilization of Sb(III) and Sb(V) by Al-rich phases - hydrous Al oxide (HAO), kaolinite (KGa-1b), and oxidized and reduced nontronite (NAu-1) - using batch experiments to determine the uptake capacity and the kinetics of adsorption and Extended X-ray Absorption Fine Structure (EXAFS) Spectroscopy to characterize the molecular environment of adsorbed Sb. Both Sb(III) and Sb(V) are adsorbed in an inner-sphere mode on the surfaces of the studied substrates. The observed adsorption geometry is mostly bidentate corner-sharing, with some monodentate complexes. The kinetics of adsorption is relatively slow (on the order of days), and equilibrium adsorption isotherms are best fit using the Freundlich model. The oxidation state of the structural Fe within nontronite affects the adsorption capacity: if the clay is reduced, the adsorption capacity of Sb(III) is slightly decreased, while Sb(V) uptake is increased significantly. This may be a result of the presence of dissolved Fe(II) in the reduced nontronite suspensions or associated with the structural rearrangements in nontronite due to reduction. These research findings indicate that Sb can be effectively immobilized by Al-rich phases. The increase in Sb(V) uptake in response to reducing structural Fe in clay can be important in natural settings since Fe-richmore » clays commonly go through oxidation-reduction cycles in response to changing redox conditions.« less

Authors:
;  [1]
  1. (Alaska Fairbanks)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
NSFDOD
OSTI Identifier:
1049572
Resource Type:
Journal Article
Journal Name:
Environ. Sci. Technol.
Additional Journal Information:
Journal Volume: 46; Journal Issue: (2) ; 01, 2012; Journal ID: ISSN 0013-936X
Country of Publication:
United States
Language:
ENGLISH
Subject:
54 ENVIRONMENTAL SCIENCES; ABSORPTION; ADSORPTION; ADSORPTION ISOTHERMS; CAPACITY; CLAYS; FINE STRUCTURE; GEOMETRY; KAOLINITE; KINETICS; OXIDES; SORPTION; SPECTROSCOPY; SUBSTRATES; VALENCE

Citation Formats

Ilgen, Anastasia G., and Trainor, Thomas P. Sb(III) and Sb(V) Sorption onto Al-Rich Phases: Hydrous Al Oxide and the Clay Minerals Kaolinite KGa-1b and Oxidized and Reduced Nontronite NAu-1. United States: N. p., 2012. Web. doi:10.1021/es203027v.
Ilgen, Anastasia G., & Trainor, Thomas P. Sb(III) and Sb(V) Sorption onto Al-Rich Phases: Hydrous Al Oxide and the Clay Minerals Kaolinite KGa-1b and Oxidized and Reduced Nontronite NAu-1. United States. doi:10.1021/es203027v.
Ilgen, Anastasia G., and Trainor, Thomas P. Tue . "Sb(III) and Sb(V) Sorption onto Al-Rich Phases: Hydrous Al Oxide and the Clay Minerals Kaolinite KGa-1b and Oxidized and Reduced Nontronite NAu-1". United States. doi:10.1021/es203027v.
@article{osti_1049572,
title = {Sb(III) and Sb(V) Sorption onto Al-Rich Phases: Hydrous Al Oxide and the Clay Minerals Kaolinite KGa-1b and Oxidized and Reduced Nontronite NAu-1},
author = {Ilgen, Anastasia G. and Trainor, Thomas P.},
abstractNote = {We have studied the immobilization of Sb(III) and Sb(V) by Al-rich phases - hydrous Al oxide (HAO), kaolinite (KGa-1b), and oxidized and reduced nontronite (NAu-1) - using batch experiments to determine the uptake capacity and the kinetics of adsorption and Extended X-ray Absorption Fine Structure (EXAFS) Spectroscopy to characterize the molecular environment of adsorbed Sb. Both Sb(III) and Sb(V) are adsorbed in an inner-sphere mode on the surfaces of the studied substrates. The observed adsorption geometry is mostly bidentate corner-sharing, with some monodentate complexes. The kinetics of adsorption is relatively slow (on the order of days), and equilibrium adsorption isotherms are best fit using the Freundlich model. The oxidation state of the structural Fe within nontronite affects the adsorption capacity: if the clay is reduced, the adsorption capacity of Sb(III) is slightly decreased, while Sb(V) uptake is increased significantly. This may be a result of the presence of dissolved Fe(II) in the reduced nontronite suspensions or associated with the structural rearrangements in nontronite due to reduction. These research findings indicate that Sb can be effectively immobilized by Al-rich phases. The increase in Sb(V) uptake in response to reducing structural Fe in clay can be important in natural settings since Fe-rich clays commonly go through oxidation-reduction cycles in response to changing redox conditions.},
doi = {10.1021/es203027v},
journal = {Environ. Sci. Technol.},
issn = {0013-936X},
number = (2) ; 01, 2012,
volume = 46,
place = {United States},
year = {2012},
month = {11}
}