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Title: Photoinduced Oxidation of Arsenite to Arsenate on Ferrihydrite

Abstract

The photochemistry of an aqueous suspension of the iron oxyhydroxide, ferrihydrite, in the presence of arsenite has been investigated using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray absorption near edge structure (XANES), and solution phase analysis. Both ATR-FTIR and XANES show that the exposure of ferrihydrite to arsenite in the dark leads to no change in the As oxidation state, but the exposure of this arsenite-bearing surface, which is in contact with pH 5 water, to light leads to the conversion of the majority of the adsorbed arsenite to the As(V) bearing species, arsenate. Analysis of the solution phase shows that ferrous iron is released into solution during the oxidation of arsenite. The photochemical reaction, however, shows the characteristics of a self-terminating reaction in that there is a significant suppression of this redox chemistry before 10% of the total iron making up the ferrihydrite partitions into solution as ferrous iron. The self-terminating behavior exhibited by this photochemical arsenite/ferrihydrite system is likely due to the passivation of the ferrihydrite surface by the strongly bound arsenate product.

Authors:
; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1041929
Report Number(s):
BNL-97607-2012-JA
Journal ID: ISSN 0013-936X; ESTHAG; TRN: US201212%%340
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 45; Journal Issue: 7; Journal ID: ISSN 0013-936X
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION; ARSENATES; BEARINGS; CHEMISTRY; IRON; OXIDATION; PASSIVATION; PHOTOCHEMICAL REACTIONS; PHOTOCHEMISTRY; REFLECTION; SPECTROSCOPY

Citation Formats

Bhandari, N, Reeder, R, and Strongin, D. Photoinduced Oxidation of Arsenite to Arsenate on Ferrihydrite. United States: N. p., 2011. Web. doi:10.1021/es103793y.
Bhandari, N, Reeder, R, & Strongin, D. Photoinduced Oxidation of Arsenite to Arsenate on Ferrihydrite. United States. https://doi.org/10.1021/es103793y
Bhandari, N, Reeder, R, and Strongin, D. 2011. "Photoinduced Oxidation of Arsenite to Arsenate on Ferrihydrite". United States. https://doi.org/10.1021/es103793y.
@article{osti_1041929,
title = {Photoinduced Oxidation of Arsenite to Arsenate on Ferrihydrite},
author = {Bhandari, N and Reeder, R and Strongin, D},
abstractNote = {The photochemistry of an aqueous suspension of the iron oxyhydroxide, ferrihydrite, in the presence of arsenite has been investigated using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray absorption near edge structure (XANES), and solution phase analysis. Both ATR-FTIR and XANES show that the exposure of ferrihydrite to arsenite in the dark leads to no change in the As oxidation state, but the exposure of this arsenite-bearing surface, which is in contact with pH 5 water, to light leads to the conversion of the majority of the adsorbed arsenite to the As(V) bearing species, arsenate. Analysis of the solution phase shows that ferrous iron is released into solution during the oxidation of arsenite. The photochemical reaction, however, shows the characteristics of a self-terminating reaction in that there is a significant suppression of this redox chemistry before 10% of the total iron making up the ferrihydrite partitions into solution as ferrous iron. The self-terminating behavior exhibited by this photochemical arsenite/ferrihydrite system is likely due to the passivation of the ferrihydrite surface by the strongly bound arsenate product.},
doi = {10.1021/es103793y},
url = {https://www.osti.gov/biblio/1041929}, journal = {Environmental Science and Technology},
issn = {0013-936X},
number = 7,
volume = 45,
place = {United States},
year = {Sat Dec 31 00:00:00 EST 2011},
month = {Sat Dec 31 00:00:00 EST 2011}
}