skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Potentiometric and electrokinetic signatures of iron(II) interactions with (a,y)-Fe2O3

Abstract

The role of surface electrostatics on the reductive dissolution of iron (III) oxides is poorly understood, despite its importance in controlling the amount of mobilized iron. We report the potentiometric titration of the a; y -Fe2O3 oxides exposed to reductants and complexing ligands (Fe(II), ascorbate, oxalate, malonate). We monitored in situ surface and potentials, the ratio of mobilized ferric to ferrous ions, and periodically analyzed nanoparticle crystal structure using X-ray diffraction. We found that addition of Fe2+ ions produces a response consistent with the iron solubilityactivity curve, whereas the presence of ascorbate significantly decreases the amount of mobilized Fe(III) due to reduction to Fe(II). In addition, XRD analysis proved that y-Fe2O3 particles remain structurally unchanged along the titration pathway despite iron cycling between aqueous and solid reservoirs. Our studies, suggest that the surface redoxactivity of iron oxides is primarily governed by the balance between Fe(III) and Fe(II) ions in aqueous phase, which may be easily altered by complexing and reducing agents.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1244818
Report Number(s):
PNNL-SA-103997
Journal ID: ISSN 1463-9076; KC0302060
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Physical Chemistry Chemical Physics. PCCP (Print)
Additional Journal Information:
Journal Volume: 17; Journal Issue: 39; Journal ID: ISSN 1463-9076
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English

Citation Formats

Toczydlowska, Diana, Kedra-Krolik, Karolina, Nejbert, Krzysztof, Preocanin, Tajana, Rosso, Kevin M., and Zarzycki, Piotr P. Potentiometric and electrokinetic signatures of iron(II) interactions with (a,y)-Fe2O3. United States: N. p., 2015. Web. doi:10.1039/C5CP03106K.
Toczydlowska, Diana, Kedra-Krolik, Karolina, Nejbert, Krzysztof, Preocanin, Tajana, Rosso, Kevin M., & Zarzycki, Piotr P. Potentiometric and electrokinetic signatures of iron(II) interactions with (a,y)-Fe2O3. United States. doi:10.1039/C5CP03106K.
Toczydlowska, Diana, Kedra-Krolik, Karolina, Nejbert, Krzysztof, Preocanin, Tajana, Rosso, Kevin M., and Zarzycki, Piotr P. Fri . "Potentiometric and electrokinetic signatures of iron(II) interactions with (a,y)-Fe2O3". United States. doi:10.1039/C5CP03106K.
@article{osti_1244818,
title = {Potentiometric and electrokinetic signatures of iron(II) interactions with (a,y)-Fe2O3},
author = {Toczydlowska, Diana and Kedra-Krolik, Karolina and Nejbert, Krzysztof and Preocanin, Tajana and Rosso, Kevin M. and Zarzycki, Piotr P.},
abstractNote = {The role of surface electrostatics on the reductive dissolution of iron (III) oxides is poorly understood, despite its importance in controlling the amount of mobilized iron. We report the potentiometric titration of the a; y -Fe2O3 oxides exposed to reductants and complexing ligands (Fe(II), ascorbate, oxalate, malonate). We monitored in situ surface and potentials, the ratio of mobilized ferric to ferrous ions, and periodically analyzed nanoparticle crystal structure using X-ray diffraction. We found that addition of Fe2+ ions produces a response consistent with the iron solubilityactivity curve, whereas the presence of ascorbate significantly decreases the amount of mobilized Fe(III) due to reduction to Fe(II). In addition, XRD analysis proved that y-Fe2O3 particles remain structurally unchanged along the titration pathway despite iron cycling between aqueous and solid reservoirs. Our studies, suggest that the surface redoxactivity of iron oxides is primarily governed by the balance between Fe(III) and Fe(II) ions in aqueous phase, which may be easily altered by complexing and reducing agents.},
doi = {10.1039/C5CP03106K},
journal = {Physical Chemistry Chemical Physics. PCCP (Print)},
issn = {1463-9076},
number = 39,
volume = 17,
place = {United States},
year = {2015},
month = {5}
}