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Arsenite and ferrous iron oxidation linked to chemolithotrophic denitrification for the immobilization of arsenic in anoxic environments

Environmental Science and Technology

By:
, , , , and
DOI: 10.1021/es900978h

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Abstract

The objective of this study was to explore a bioremediation strategy based on injecting NO3- to support the anoxic oxidation of ferrous iron (Fe(II)) and arsenite (As(III)) in the subsurface as a means to immobilize As in the form of arsenate (As(V)) adsorbed onto biogenic ferric (Fe(III)) (hydr)oxides. Continuous flows and filled columns were used to simulate a natural anaerobic groundwater and sediment system with co-occurring As(III) and Fe(II) in the presence (column SF1) or absence (column SF2) of nitrate, respectively. During operation for 250 days, the average influent arsenic concentration of 567 ??g L-1 was reduced to 10.6 (??9.6) ??g L-1 in the effluent of column SF1. The cumulative removal of Fe(II) and As(III) in SF1 was 6.5 to 10-fold higher than that in SF2. Extraction and measurement of the mass of iron and arsenic immobilized on the sand packing of the columns were close to the iron and arsenic removed from the aqueous phase during column operation. The dominant speciation of the immobilized iron and arsenic was Fe(III) and As(V) in SF1, compared with Fe(II) and As(III) in SF2. The speciation was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicate that microbial oxidation of As(III) and Fe(II) linked to denitrification resulted in the enhanced immobilization of aqueous arsenic in anaerobic environments by forming Fe(III) (hydr)oxide coated sands with adsorbed As(V). ?? 2009 American Chemical Society.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Arsenite and ferrous iron oxidation linked to chemolithotrophic denitrification for the immobilization of arsenic in anoxic environments
Series title:
Environmental Science and Technology
DOI:
10.1021/es900978h
Volume
43
Issue:
17
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Environmental Science and Technology
First page:
6585
Last page:
6591