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| Titel |
Transport of iron oxide nanoparticles in saturated porous media: a
large-scale 3D study |
| VerfasserIn |
Milica Velimirovic, Doris Schmid, Vesna Micić, Kumiko Miyajima, Norbert Klaas, Jürgen Braun, Julian Bosch, Rainer Meckenstock, Frank von der Kammer, Thilo Hofmann  |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250126010
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| Publikation (Nr.) |
 EGU/EGU2016-5678.pdf |
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| Zusammenfassung |
| Iron oxide nanoparticles (FeOxNp) have a high potential as electron acceptor for in situ
microbial oxidation of a wide range of recalcitrant groundwater contaminants (Bosch et al.,
2010). Tosco et al. (2012) reported on high colloidal stability of FeOxNp dispersed in water,
their low deposition behavior, and consequently improved transport in column experiments
compared to extensively studied zerovalent iron nanoparticles. However, determination
of FeOxNp transport behavior at the field-relevant conditions has not been done
before.
The present work is aimed to evaluate different complementary methods for detection,
quantification and transport characterization of FeOxNp in a large-scale three-dimensional
(3D) model aquifer. Prior to that, batch-scale experiments were performed in order to
elucidate the potential of the selected methods for direct and indirect characterization and
detection of FeOxNp. Direct methods included measurements of particle size distribution,
particle concentration, Fetot content and turbidity of the FeOxNp suspension. Indirect
methods included measurements of particle zeta potential, as well as TOC content and pH of
the FeOxNp suspension. The results of the batch experiments indicated that the
most suitable approach for detecting and quantifying FeOxNp was measuring Fetot
content and suspension turbidity, as well as particle size determined using dynamic
light scattering principle. These complementary methods were further applied in a
large-scale 3D study containing medium and coarse sand in order to 1) assess the
transport of FeOxNp in saturated porous medium during injection (VFeOx = 6 m3,
cparticle = 20 g/L, Qinj = 0.7 m3/h), and 2) illustrate their spatial distribution after
injection.
The outcomes of the large-scale 3D study confirmed that FeOxNp transport can be
successfully investigated applying complementary methods. Monitoring data including Fetot
content, turbidity and particle size showed the transport of particles towards the coarse sand
regions creating a radius of influence of 1.5 m. Finally, migration distance of FeOxNp was
more than 2 m from injection point towards to high permeability zone indicating that the
permeability of porous media does have an important impact on particle transport after
injection.
A drawback of all the tested methods is their inability to distinguish between natural and
engineered FeOxNp, which might be an obstacle for applying them when the Fetot
concentrations approach the background levels. In this case other techniques need to be
applied.
This research receives funding from the European Union’s Seventh Framework
Programme FP7/2007-2013 under grant agreement n˚ 309517. |
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