Synthesis, Characterization, and Properties of Zero-Valent Iron Nanoparticles

Baer, Donald R.; Tratnyek, Paul G.; Qiang, You; Amonette, J. E.; Linehan, John C.; Sarathy, Vaishnavi; Nurmi, James T.; Wang, C.-M.; Antony, Jiji

doi:10.1142/9781860948572_0003

Cited by 13 publications

(8 citation statements)

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“…[17] The second type of particle was produced by a sputter-gasaggregation process in vacuum Fe SP . [18,22] The TEM images indicate that these are core/shell particles made up of ∼10-14 nm particles with ∼2-3-nm thick oxide shells. The XRD data (line width and ratio of metal to oxide) are also quite consistent with the TEM data.…”

Section: Time-dependent Properties Of Fe Nanoparticlesmentioning

confidence: 99%

Characterization challenges for nanomaterials

Baer

Amonette

Engelhard

et al. 2008

Surface & Interface Analysis

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122

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Nanostructured materials are increasingly subject to nearly every type of chemical and physical analysis possible. Due to their small sizes, there is a significant focus on tools with high spatial resolution. It is also natural to characterize nanomaterials using tools designed to analyze surfaces, because of their high surface area. Regardless of the approach, nanostructured materials present a variety of obstacles to adequate, useful, and needed analysis. Case studies of measurements on ceria and iron metal-core/oxide-shell nanoparticles are used to introduce some of the issues that frequently need to be addressed during analysis of nanostructured materials. We use a combination of tools for routine analysis including X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and x-ray diffraction (XRD) and apply several other methods as needed to obtain essential information. The examples provide an introduction to other issues and complications associated with the analysis of nanostructured materials including particle stability, probe effects, environmental effects, specimen handling, surface coating, contamination, and time.

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Section: Time-dependent Properties Of Fe Nanoparticlesmentioning

confidence: 99%

Characterization challenges for nanomaterials

Baer

Amonette

Engelhard

et al. 2008

Surface & Interface Analysis

Self Cite

122

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“…33 ). Without recovered solids, characterization of the nZVI using standard methods for nanomaterials (transmission electron microscopy, X-ray absorption spectroscopy, and X-ray diffraction 34 ) is generally not feasible. Instead, characterization of the fate of CMC-nZVI, in both lab and field studies, has been based mainly on methods that provide bulk analyses of solution samples.…”

Section: ■ Introductionmentioning

confidence: 99%

Field Deployable Chemical Redox Probe for Quantitative Characterization of Carboxymethylcellulose Modified Nano Zerovalent Iron

Fan

Chen

Johnson

et al. 2015

Environ. Sci. Technol.

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Nano zerovalent iron synthesized with carboxymethylcelluose (CMC-nZVI) is among the leading formulations of nZVI currently used for in situ groundwater remediation. The main advantage of CMC-nZVI is that it forms stable suspensions, which are relatively mobile in porous media. Rapid contaminant reduction by CMC-nZVI is well documented, but the fate of the CMC-nZVI (including "aging" and "reductant demand") is not well characterized. Improved understanding of CMC-nZVI fate requires methods with greater specificity for Fe(0), less vulnerability to sampling/recovery artifacts, and more practical application in the field. These criteria can be met with a simple and specific colorimetric approach using indigo-5,5'-disulfonate (I2S) as a chemical redox probe (CRP). The measured stoichiometric ratio for reaction between I2S and nZVI is 1.45 ± 0.03, suggesting complete oxidation of nZVI to Fe(III) species. However, near pH 7, reduction of I2S is diagnostic for Fe(0), because aqueous Fe(II) reduces I2S much more slowly than Fe(0). At that pH, adding Fe(II) increased I2S reduction rates by Fe(0), consistent with depassivation of nZVI, but did not affect the stoichiometry. Using the I2S assay to quantify changes in the Fe(0) content of CMC-nZVI, the rate of Fe(0) oxidation by water was found to be orders of magnitude faster than previously reported values for other types of nZVI.

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“…The above limitations to conventional PRBs using construction-grade Fe 0 can be addressed by using nanosized Fe 0 , which has the potential to be (i) more reactive with target contaminants, (ii) more benign in the products produced, and (iii) mobile in porous media (and therefore suitable for emplacement by injection). − While nano-Fe 0 clearly has great promise for a range of remediation applications, there are important aspects of the environmental fate and effects of nano-Fe 0 that are not well understood or where the understanding at this time may even be misleading. , One of the most significant uncertaintieswith implications for both engineering design and assessment of potential collateral impactsis how particles of nano-Fe 0 change during immersion in water (i.e., aging). In this work, we investigate the aging of nano-Fe 0 particles in water, focusing on changes in their composition, structure, and reactivity.…”

Section: Introductionmentioning

confidence: 99%

Aging of Iron Nanoparticles in Aqueous Solution: Effects on Structure and Reactivity

et al. 2008

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Aging (or longevity) is one of the most important and potentially limiting factors in the use of nano-Fe 0 to reduce groundwater contaminants. We investigated the aging of Fe H2 (Toda RNIP-10DS) in water with a focus on changes in (i) the composition and structure of the particles (by XRD, TEM, XPS, and bulk Fe 0 content) and (ii) the reactivity of the particles (by carbon tetrachloride reaction kinetics, electrochemical corrosion potentials, and H 2 production rates). Our results show that Fe H2 becomes more reactive between 0 and ∼2 days exposure to water 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 Fe H2 during immersion and the subsequent formation of a new passivating mixed-valence Fe(II)-Fe(III) oxide shell. The effect of aging on the rate of carbon tetrachloride reduction was best described by the corrosion potential of Fe H2 , whereas the yield of chloroform from this reaction correlated best with the rate of H 2 production. The behavior of unaged nano-Fe 0 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 Fe H2 acquires properties that are relatively stable over weeks or even months.

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Synthesis, Characterization, and Properties of Zero-Valent Iron Nanoparticles

Cited by 13 publications

References 0 publications

Characterization challenges for nanomaterials

Characterization challenges for nanomaterials

Field Deployable Chemical Redox Probe for Quantitative Characterization of Carboxymethylcellulose Modified Nano Zerovalent Iron

Aging of Iron Nanoparticles in Aqueous Solution: Effects on Structure and Reactivity

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