Iron-rich nanoparticles in natural aquatic environments
Date
2019-05-11
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
Naturally-occurring iron nanoparticles constitute a quantitatively-important and
biogeochemically-active component of the broader Earth ecosystem. Yet detailed insights into
their chemical speciation is sparse compared to the body of work conducted on engineered Fe
nanoparticles. The present contribution briefly reviews the analytical approaches that can be used
to characterize natural Fe nanoparticles, before detailing a dedicated synchrotron-based X-ray
spectro-microscopic investigation into the speciation of suspended Fe nanoparticles collected from
fluvial, marine, and lacustrine surface waters. Ferrous, ferric and magnetite classes of Fe nanoparticles
(10–100 nm) were identified, and all three classes exhibited a high degree of heterogeneity in the local
bonding environment around the Fe center. The heterogeneity is attributed to the possible presence of
nanoparticle aggregates, and to the low degrees of crystallinity and ubiquitous presence of impurities
(Al and organic moieties) in natural samples. This heterogeneity further precludes a spectroscopic
distinction between the Fe nanoparticles and the larger sized Fe-rich particles that were evaluated.
The presented results provide an important baseline for natural nanoparticle speciation in pristine
aquatic systems, highlight the degree of inter-particle variability, which should be parameterized in
future accurate biogeochemical models, and may inform predictions of the fate of released engineered
Fe nanoparticles as they evolve and transform in natural systems.
Description
CITATION: Von der Heyden, B., Roychoudhury, A. & Myneni, S. 2019. Iron-rich nanoparticles in natural aquatic environments. Minerals, 9(5):287, doi:10.3390/min9050287 .
The original publication is available at https://www.mdpi.com
Publication of this article was funded by the Stellenbosch University Open Access Fund.
The original publication is available at https://www.mdpi.com
Publication of this article was funded by the Stellenbosch University Open Access Fund.
Keywords
Iron nanoparticles, Nanoparticles -- Analysis, Engineered iron nanoparticles, Natural iron nanoparticles, Ocean biogeochemistry models
Citation
Von der Heyden, B., Roychoudhury, A. & Myneni, S. 2019. Iron-rich nanoparticles in natural aquatic environments. Minerals, 9(5):287, doi:10.3390/min9050287