Transformation of natural ferrihydrite aged in situ in As, Cr and Cu contaminated soil studied by reduction kinetics

Sanne Skov Nielsen, Peter Kjeldsen, Hans Christian Bruun Hansen, Rasmus Jakobsen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Several soil remediation techniques for As, Cu and Cr contaminated soil utilize adsorption of contaminants to ferrihydrite as the removal mechanism, even though ferrihydrite will transform to secondary iron oxides and part of the sorption capacity will be lost. Transformation of ferrihydrite following 4 yr of in situ burial at a contaminated site was examined in samples of impure (Si-bearing) ferrihydrite in soil heavily polluted with As, Cr and Cu. The samples are so-called iron water treatment residues (Fe-WTR) precipitated from anoxic groundwater during aeration. The extent of transformation of ferrihydrites in the field was evaluated in the lab through experiments where the kinetics of iron and contaminant release was studied in a pH 3 ascorbic acid solution. Compared to fresh controls the aged samples had scavenged significant amounts of contaminants (up to 9.2 mmolAs/molFe and 1.5 mmolCu/molFe) and the reactivity had decreased by one order of magnitude, indicating partial transformation of ferrihydrite to more crystalline iron phases. Iron crystallinity increased during the 4 yr of aging with XRD suggesting goethite, alpha-FeO(OH), to be the most prominent transformation products. The study clarifies the fate of ferrihydrite and associated contaminants during burial enabling an improvement of the methods for amending contaminated soil with Fe-WTR. (C) 2014 Elsevier Ltd. All rights reserved.
Original languageEnglish
JournalApplied Geochemistry
Volume51
Pages (from-to)293-302
Number of pages10
ISSN0883-2927
DOIs
Publication statusPublished - 2014

Keywords

  • GEOCHEMISTRY
  • DISSIMILATORY IRON REDUCTION
  • CHROMATED COPPER ARSENATE
  • WATER TREATMENT RESIDUALS
  • SYNTHETIC FERRIHYDRITE
  • AQUEOUS FE(II)
  • OXIDE MINERALS
  • ASCORBIC-ACID
  • GOETHITE
  • DISSOLUTION
  • HEMATITE

Cite this

Nielsen, Sanne Skov ; Kjeldsen, Peter ; Hansen, Hans Christian Bruun ; Jakobsen, Rasmus. / Transformation of natural ferrihydrite aged in situ in As, Cr and Cu contaminated soil studied by reduction kinetics. In: Applied Geochemistry. 2014 ; Vol. 51. pp. 293-302.
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abstract = "Several soil remediation techniques for As, Cu and Cr contaminated soil utilize adsorption of contaminants to ferrihydrite as the removal mechanism, even though ferrihydrite will transform to secondary iron oxides and part of the sorption capacity will be lost. Transformation of ferrihydrite following 4 yr of in situ burial at a contaminated site was examined in samples of impure (Si-bearing) ferrihydrite in soil heavily polluted with As, Cr and Cu. The samples are so-called iron water treatment residues (Fe-WTR) precipitated from anoxic groundwater during aeration. The extent of transformation of ferrihydrites in the field was evaluated in the lab through experiments where the kinetics of iron and contaminant release was studied in a pH 3 ascorbic acid solution. Compared to fresh controls the aged samples had scavenged significant amounts of contaminants (up to 9.2 mmolAs/molFe and 1.5 mmolCu/molFe) and the reactivity had decreased by one order of magnitude, indicating partial transformation of ferrihydrite to more crystalline iron phases. Iron crystallinity increased during the 4 yr of aging with XRD suggesting goethite, alpha-FeO(OH), to be the most prominent transformation products. The study clarifies the fate of ferrihydrite and associated contaminants during burial enabling an improvement of the methods for amending contaminated soil with Fe-WTR. (C) 2014 Elsevier Ltd. All rights reserved.",
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Transformation of natural ferrihydrite aged in situ in As, Cr and Cu contaminated soil studied by reduction kinetics. / Nielsen, Sanne Skov; Kjeldsen, Peter; Hansen, Hans Christian Bruun; Jakobsen, Rasmus.

In: Applied Geochemistry, Vol. 51, 2014, p. 293-302.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Transformation of natural ferrihydrite aged in situ in As, Cr and Cu contaminated soil studied by reduction kinetics

AU - Nielsen, Sanne Skov

AU - Kjeldsen, Peter

AU - Hansen, Hans Christian Bruun

AU - Jakobsen, Rasmus

PY - 2014

Y1 - 2014

N2 - Several soil remediation techniques for As, Cu and Cr contaminated soil utilize adsorption of contaminants to ferrihydrite as the removal mechanism, even though ferrihydrite will transform to secondary iron oxides and part of the sorption capacity will be lost. Transformation of ferrihydrite following 4 yr of in situ burial at a contaminated site was examined in samples of impure (Si-bearing) ferrihydrite in soil heavily polluted with As, Cr and Cu. The samples are so-called iron water treatment residues (Fe-WTR) precipitated from anoxic groundwater during aeration. The extent of transformation of ferrihydrites in the field was evaluated in the lab through experiments where the kinetics of iron and contaminant release was studied in a pH 3 ascorbic acid solution. Compared to fresh controls the aged samples had scavenged significant amounts of contaminants (up to 9.2 mmolAs/molFe and 1.5 mmolCu/molFe) and the reactivity had decreased by one order of magnitude, indicating partial transformation of ferrihydrite to more crystalline iron phases. Iron crystallinity increased during the 4 yr of aging with XRD suggesting goethite, alpha-FeO(OH), to be the most prominent transformation products. The study clarifies the fate of ferrihydrite and associated contaminants during burial enabling an improvement of the methods for amending contaminated soil with Fe-WTR. (C) 2014 Elsevier Ltd. All rights reserved.

AB - Several soil remediation techniques for As, Cu and Cr contaminated soil utilize adsorption of contaminants to ferrihydrite as the removal mechanism, even though ferrihydrite will transform to secondary iron oxides and part of the sorption capacity will be lost. Transformation of ferrihydrite following 4 yr of in situ burial at a contaminated site was examined in samples of impure (Si-bearing) ferrihydrite in soil heavily polluted with As, Cr and Cu. The samples are so-called iron water treatment residues (Fe-WTR) precipitated from anoxic groundwater during aeration. The extent of transformation of ferrihydrites in the field was evaluated in the lab through experiments where the kinetics of iron and contaminant release was studied in a pH 3 ascorbic acid solution. Compared to fresh controls the aged samples had scavenged significant amounts of contaminants (up to 9.2 mmolAs/molFe and 1.5 mmolCu/molFe) and the reactivity had decreased by one order of magnitude, indicating partial transformation of ferrihydrite to more crystalline iron phases. Iron crystallinity increased during the 4 yr of aging with XRD suggesting goethite, alpha-FeO(OH), to be the most prominent transformation products. The study clarifies the fate of ferrihydrite and associated contaminants during burial enabling an improvement of the methods for amending contaminated soil with Fe-WTR. (C) 2014 Elsevier Ltd. All rights reserved.

KW - GEOCHEMISTRY

KW - DISSIMILATORY IRON REDUCTION

KW - CHROMATED COPPER ARSENATE

KW - WATER TREATMENT RESIDUALS

KW - SYNTHETIC FERRIHYDRITE

KW - AQUEOUS FE(II)

KW - OXIDE MINERALS

KW - ASCORBIC-ACID

KW - GOETHITE

KW - DISSOLUTION

KW - HEMATITE

U2 - 10.1016/j.apgeochem.2014.10.014

DO - 10.1016/j.apgeochem.2014.10.014

M3 - Journal article

VL - 51

SP - 293

EP - 302

JO - Applied Geochemistry

JF - Applied Geochemistry

SN - 0883-2927

ER -