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Title: Effect of Aqueous Fe(II) on Arsenate Sorption on Goethite and Hematite

Abstract

Biogeochemical iron cycling often generates systems where aqueous Fe(II) and solid Fe(III) oxides coexist. Reactions between these species result in iron oxide surface and phase transformations, iron isotope fractionation, and redox transformations of many contaminant species. Fe(II)-induced recrystallization of goethite and hematite has recently been shown to cause the repartitioning of Ni(II) at the mineral-water interface, with adsorbed Ni incorporating into the iron oxide structure and preincorporated Ni released back into aqueous solution. However, the effect of Fe(II) on the fate and speciation of redox inactive species incompatible with iron oxide structures is unclear. Arsenate sorption to hematite and goethite in the presence of aqueous Fe(II) was studied to determine whether Fe(II) causes substantial changes in the sorption mechanisms of such incompatible species. Sorption isotherms reveal that Fe(II) minimally alters macroscopic arsenate sorption behavior except at circumneutral pH in the presence of elevated concentrations (10{sup -3} M) of Fe(II) and at high arsenate loadings, where a clear signature of precipitation is observed. Powder X-ray diffraction demonstrates that the ferrous arsenate mineral symplesite precipitates under such conditions. Extended X-ray absorption fine structure spectroscopy shows that outside this precipitation regime arsenate surface complexation mechanisms are unaffected by Fe(II). In addition, arsenate wasmore » found to suppress Fe(II) sorption through competitive adsorption processes before the onset of symplesite precipitation. This study demonstrates that the sorption of species incompatible with iron oxide structure is not substantially affected by Fe(II) but that such species may potentially interfere with Fe(II)-iron oxide reactions via competitive adsorption.« less

Authors:
; ;  [1]
  1. WU
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF)
OSTI Identifier:
1027659
Resource Type:
Journal Article
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 45; Journal Issue: 20; Journal ID: ISSN 0013-936X
Country of Publication:
United States
Language:
ENGLISH
Subject:
54 ENVIRONMENTAL SCIENCES; ABSORPTION; ADSORPTION; AQUEOUS SOLUTIONS; ARSENATES; FINE STRUCTURE; FRACTIONATION; GOETHITE; HEMATITE; IRON; IRON ISOTOPES; IRON OXIDES; ISOTHERMS; OXIDES; PHASE TRANSFORMATIONS; PRECIPITATION; RECRYSTALLIZATION; SORPTION; SPECTROSCOPY; TRANSFORMATIONS; X-RAY DIFFRACTION

Citation Formats

Catalano, Jeffrey G, Luo, Yun, and Otemuyiwa, Bamidele. Effect of Aqueous Fe(II) on Arsenate Sorption on Goethite and Hematite. United States: N. p., 2011. Web. doi:10.1021/es202445w.
Catalano, Jeffrey G, Luo, Yun, & Otemuyiwa, Bamidele. Effect of Aqueous Fe(II) on Arsenate Sorption on Goethite and Hematite. United States. https://doi.org/10.1021/es202445w
Catalano, Jeffrey G, Luo, Yun, and Otemuyiwa, Bamidele. 2011. "Effect of Aqueous Fe(II) on Arsenate Sorption on Goethite and Hematite". United States. https://doi.org/10.1021/es202445w.
@article{osti_1027659,
title = {Effect of Aqueous Fe(II) on Arsenate Sorption on Goethite and Hematite},
author = {Catalano, Jeffrey G and Luo, Yun and Otemuyiwa, Bamidele},
abstractNote = {Biogeochemical iron cycling often generates systems where aqueous Fe(II) and solid Fe(III) oxides coexist. Reactions between these species result in iron oxide surface and phase transformations, iron isotope fractionation, and redox transformations of many contaminant species. Fe(II)-induced recrystallization of goethite and hematite has recently been shown to cause the repartitioning of Ni(II) at the mineral-water interface, with adsorbed Ni incorporating into the iron oxide structure and preincorporated Ni released back into aqueous solution. However, the effect of Fe(II) on the fate and speciation of redox inactive species incompatible with iron oxide structures is unclear. Arsenate sorption to hematite and goethite in the presence of aqueous Fe(II) was studied to determine whether Fe(II) causes substantial changes in the sorption mechanisms of such incompatible species. Sorption isotherms reveal that Fe(II) minimally alters macroscopic arsenate sorption behavior except at circumneutral pH in the presence of elevated concentrations (10{sup -3} M) of Fe(II) and at high arsenate loadings, where a clear signature of precipitation is observed. Powder X-ray diffraction demonstrates that the ferrous arsenate mineral symplesite precipitates under such conditions. Extended X-ray absorption fine structure spectroscopy shows that outside this precipitation regime arsenate surface complexation mechanisms are unaffected by Fe(II). In addition, arsenate was found to suppress Fe(II) sorption through competitive adsorption processes before the onset of symplesite precipitation. This study demonstrates that the sorption of species incompatible with iron oxide structure is not substantially affected by Fe(II) but that such species may potentially interfere with Fe(II)-iron oxide reactions via competitive adsorption.},
doi = {10.1021/es202445w},
url = {https://www.osti.gov/biblio/1027659}, journal = {Environmental Science and Technology},
issn = {0013-936X},
number = 20,
volume = 45,
place = {United States},
year = {2011},
month = {11}
}