Nitrate Reduction by Surface-Bound Fe(II) on Solid Surfaces at Near-Neutral pH and Ambient Temperature

Yong H. Huang, Tian C. Zhang

Research output: Contribution to journalArticle

Abstract

Nitrate reduction by Fe(II) species was previously known to occur only in Cu2+-catalyzed and alkaline conditions or at high temperatures. In this study, a reactant system consisting of nitrate, iron oxide particles, and Fe(II) (in different forms) was used to study possible reactions between nitrate and Fe(II). At near-neutral pH, nitrate could not be reduced by aqueous Fe(II) species or by Fe(OH)2 gel. In the presence of magnetite (Fe3O4) particles, however, a significant amount of Fe2+ could be adsorbed onto an Fe3O4 surface at pH=7.3 and became surface-bound Fe2+(S.B. Fe2+), which could react with nitrate via the reaction: 12 S.B. Fe2++NO3-+13 H2O 4 Fe3O4 +NH4++22 H+. The reaction stopped when pH decreased to <6.8. Introducing trace amount of O2 or Fe3+(aq) into the nitrate-Fe2+ reactant system was as effective as seeding magnetite particles in triggering the nitrate-Fe(II) reaction, suggesting that lepidocrocite (γ-FeOOH) is a precursor for initiating the nitrate-Fe(II) reaction. Hematite and Kaolinite particles could also serve as the reactive sites for the nitrate-Fe(II) reaction upon surface transformation by S.B. Fe2+. The observed abiotic nitrate reduction by Fe(II) could be an important link between the nitrogen cycling and the Fe(II)/Fe(III) redox couple in the biosphere or geosphere.

Original languageEnglish (US)
Article number4016053
JournalJournal of Environmental Engineering (United States)
Volume142
Issue number11
DOIs
StatePublished - Nov 1 2016

Fingerprint

Nitrates
nitrate
temperature
Temperature
Ferrosoferric Oxide
Surface reactions
Magnetite
magnetite
Kaolin
lepidocrocite
Kaolinite
Hematite
seeding
Iron oxides
iron oxide
biosphere
hematite
Particles (particulate matter)
kaolinite
Nitrogen

Keywords

  • Ferrous ion
  • Iron oxides
  • Nitrate reduction
  • Solid surfaces
  • pH

ASJC Scopus subject areas

  • Environmental Engineering
  • Civil and Structural Engineering
  • Environmental Chemistry
  • Environmental Science(all)

Cite this

Nitrate Reduction by Surface-Bound Fe(II) on Solid Surfaces at Near-Neutral pH and Ambient Temperature. / Huang, Yong H.; Zhang, Tian C.

In: Journal of Environmental Engineering (United States), Vol. 142, No. 11, 4016053, 01.11.2016.

Research output: Contribution to journalArticle

@article{9c761b6ba5a442f092e00aeb6e205644,
title = "Nitrate Reduction by Surface-Bound Fe(II) on Solid Surfaces at Near-Neutral pH and Ambient Temperature",
abstract = "Nitrate reduction by Fe(II) species was previously known to occur only in Cu2+-catalyzed and alkaline conditions or at high temperatures. In this study, a reactant system consisting of nitrate, iron oxide particles, and Fe(II) (in different forms) was used to study possible reactions between nitrate and Fe(II). At near-neutral pH, nitrate could not be reduced by aqueous Fe(II) species or by Fe(OH)2 gel. In the presence of magnetite (Fe3O4) particles, however, a significant amount of Fe2+ could be adsorbed onto an Fe3O4 surface at pH=7.3 and became surface-bound Fe2+(S.B. Fe2+), which could react with nitrate via the reaction: 12 S.B. Fe2++NO3-+13 H2O 4 Fe3O4 +NH4++22 H+. The reaction stopped when pH decreased to <6.8. Introducing trace amount of O2 or Fe3+(aq) into the nitrate-Fe2+ reactant system was as effective as seeding magnetite particles in triggering the nitrate-Fe(II) reaction, suggesting that lepidocrocite (γ-FeOOH) is a precursor for initiating the nitrate-Fe(II) reaction. Hematite and Kaolinite particles could also serve as the reactive sites for the nitrate-Fe(II) reaction upon surface transformation by S.B. Fe2+. The observed abiotic nitrate reduction by Fe(II) could be an important link between the nitrogen cycling and the Fe(II)/Fe(III) redox couple in the biosphere or geosphere.",
keywords = "Ferrous ion, Iron oxides, Nitrate reduction, Solid surfaces, pH",
author = "Huang, {Yong H.} and Zhang, {Tian C.}",
year = "2016",
month = "11",
day = "1",
doi = "10.1061/(ASCE)EE.1943-7870.0001130",
language = "English (US)",
volume = "142",
journal = "Journal of Environmental Engineering, ASCE",
issn = "0733-9372",
publisher = "American Society of Civil Engineers (ASCE)",
number = "11",

}

TY - JOUR

T1 - Nitrate Reduction by Surface-Bound Fe(II) on Solid Surfaces at Near-Neutral pH and Ambient Temperature

AU - Huang, Yong H.

AU - Zhang, Tian C.

PY - 2016/11/1

Y1 - 2016/11/1

N2 - Nitrate reduction by Fe(II) species was previously known to occur only in Cu2+-catalyzed and alkaline conditions or at high temperatures. In this study, a reactant system consisting of nitrate, iron oxide particles, and Fe(II) (in different forms) was used to study possible reactions between nitrate and Fe(II). At near-neutral pH, nitrate could not be reduced by aqueous Fe(II) species or by Fe(OH)2 gel. In the presence of magnetite (Fe3O4) particles, however, a significant amount of Fe2+ could be adsorbed onto an Fe3O4 surface at pH=7.3 and became surface-bound Fe2+(S.B. Fe2+), which could react with nitrate via the reaction: 12 S.B. Fe2++NO3-+13 H2O 4 Fe3O4 +NH4++22 H+. The reaction stopped when pH decreased to <6.8. Introducing trace amount of O2 or Fe3+(aq) into the nitrate-Fe2+ reactant system was as effective as seeding magnetite particles in triggering the nitrate-Fe(II) reaction, suggesting that lepidocrocite (γ-FeOOH) is a precursor for initiating the nitrate-Fe(II) reaction. Hematite and Kaolinite particles could also serve as the reactive sites for the nitrate-Fe(II) reaction upon surface transformation by S.B. Fe2+. The observed abiotic nitrate reduction by Fe(II) could be an important link between the nitrogen cycling and the Fe(II)/Fe(III) redox couple in the biosphere or geosphere.

AB - Nitrate reduction by Fe(II) species was previously known to occur only in Cu2+-catalyzed and alkaline conditions or at high temperatures. In this study, a reactant system consisting of nitrate, iron oxide particles, and Fe(II) (in different forms) was used to study possible reactions between nitrate and Fe(II). At near-neutral pH, nitrate could not be reduced by aqueous Fe(II) species or by Fe(OH)2 gel. In the presence of magnetite (Fe3O4) particles, however, a significant amount of Fe2+ could be adsorbed onto an Fe3O4 surface at pH=7.3 and became surface-bound Fe2+(S.B. Fe2+), which could react with nitrate via the reaction: 12 S.B. Fe2++NO3-+13 H2O 4 Fe3O4 +NH4++22 H+. The reaction stopped when pH decreased to <6.8. Introducing trace amount of O2 or Fe3+(aq) into the nitrate-Fe2+ reactant system was as effective as seeding magnetite particles in triggering the nitrate-Fe(II) reaction, suggesting that lepidocrocite (γ-FeOOH) is a precursor for initiating the nitrate-Fe(II) reaction. Hematite and Kaolinite particles could also serve as the reactive sites for the nitrate-Fe(II) reaction upon surface transformation by S.B. Fe2+. The observed abiotic nitrate reduction by Fe(II) could be an important link between the nitrogen cycling and the Fe(II)/Fe(III) redox couple in the biosphere or geosphere.

KW - Ferrous ion

KW - Iron oxides

KW - Nitrate reduction

KW - Solid surfaces

KW - pH

UR - http://www.scopus.com/inward/record.url?scp=84991677980&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84991677980&partnerID=8YFLogxK

U2 - 10.1061/(ASCE)EE.1943-7870.0001130

DO - 10.1061/(ASCE)EE.1943-7870.0001130

M3 - Article

AN - SCOPUS:84991677980

VL - 142

JO - Journal of Environmental Engineering, ASCE

JF - Journal of Environmental Engineering, ASCE

SN - 0733-9372

IS - 11

M1 - 4016053

ER -