Aging of Iron Nanoparticles in Aqueous Solution: Effects on Structure and Reactivity
Aging (or longevity) is one of the most important and potentially limiting factors in the use of nano-Fe0 to reduce groundwater contaminants. We investigated the aging of FeH2 (Toda RNIP-10DS) in water with a focus on changes in (i) the composition and structure of the particles (by XPS, XRD, TEM, and bulk Fe0 content), and (ii) the reactivity of the particles (by carbon tetrachloride reaction kinetics and electrochemical corrosion potentials). Our results show that the FeH2 becomes more reactive between 0 and ~2 days aging, and then gradually loses reactivity over the next few hundred days. These changes in reactivity correlate with evidence for rapid destruction of the original Fe(III) oxide film on FeH2 during immersion and the subsequent formation of a new passivating mixed-valence Fe(II)-Fe(III) oxide shell. The behavior of “unaged” nano-Fe0 in the laboratory may be similar to that in field-scale applications for source-zone treatment due to the short reaction times involved. Long-term aged FeH2 acquires properties that are relatively stable over weeks or even months.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 926931
- Report Number(s):
- PNNL-SA-57321; 2573b; KP1504010
- Journal Information:
- Journal of Physical Chemistry C, 112(7):2286-2293, Journal Name: Journal of Physical Chemistry C, 112(7):2286-2293
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structural response of phyllomanganates to wet aging and aqueous Mn(II)
Effects of aging and oxidation of palladized iron embedded in activated carbon on the dechlorination of 2-chlorobiphenyl