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| Titel |
Colloid/Nanoparticle mobility determining processes investigated by laser- and synchrotron based techniques |
| VerfasserIn |
Thorsten Schäfer, Florian Huber, Louis Temgoua, Francis Claret, Gopala Darbha, Aurélie Chagneau, Cornelius Fischer, Chris Jacobsen |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093622
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| Publikation (Nr.) |
 EGU/EGU2014-8522.pdf |
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| Zusammenfassung |
| Transport of pollutants can occur in the aqueous phase or for strongly sorbing pollutants
associated on mobile solid phases spanning the range from a couple of nanometers up to
approx. ~1μm; usually called colloids or nanoparticles [1,2]. A new form of pollutants are
engineered nanoparticles (ENP’s), where properties differ substantially from those of bulk
materials of the same composition and cannot be scaled by simple surface area corrections.
Potential harmful interactions with biological systems and the environment are a new field of
research [3]. A challenge with respect to understand and predict the contaminant mobility
is the contaminant speciation, the aquifer surface interaction and the mobility of
nanoparticles. Especially for colloid/nanoparticle associated contaminant transport the
metal sorption reversibility is a key element for long-term mobility prediction. The
spatial resolution needed is clearly demanding for nanoscopic techniques benefiting
from the new technical developments in the laser and synchrotron community [4].
Furthermore, high energy resolution is needed to either resolve different chemical
species or the oxidation state of redox sensitive elements. In the context of successful
planning of remediation strategies for contaminated sites this chemical information is
categorically needed. In addition, chemical sensitivity as well as post processing
methods extracting trace chemical information from a complex geo-matrix are
required.
The presentation will give examples of homogeneous and heterogeneous nucleation of
nanoparticles [5], the speciation of radionuclides through incorporation in these newly
formed phases [6], the changes of surface roughness and charge heterogeneity and its impact
on nanoparticle mobility [7] and the sorption of organic colloids on mineral surfaces
leading to functional group fractionation and consequently different metal binding
environment as unraveled by time resolved laser fluorescence measurements [8].
Furthermore, aquifer flow path heterogeneity is driving the mobility/retention of
colloids/nanoparticles, which can be resolved by tomographic (CT) methods [9].
Reactive transport models use usually simplified geometrical assumptions which
are essential to properly predict pore clogging. Here, implementation of 3D μCT
information will overcome these shortcomings. Examples of contaminant transport
up-scaling from laboratory scale (μm-dm) to field scale experiments in underground
research laboratories (URL’s) will be discussed and based inter alia on the examples
given current challenges and potential new directions will be highlighted in the
presentation.
[1] T. Schäfer, F. Huber, H. Seher, T. Missana, S. Eidner, F. Enzmann Appl. Geochem.
2012, 27, 390. [2] R. Kretzschmar, T. Schäfer Elements 2005, 1, 205. [3] B. Nowack, T.D.
Bucheli Environmental Pollution 2007, 150, 5. [4] R. Falcone, C. Jacobsen, J. Kirz, D.
Shapiro, J. Spence Contemporary Physics 2011, 52, 293-318. [5] F. Brandt, T. Schäfer, F.
Claret, D. Bosbach Chem. Geol. 2012, 329, 42-52. [6] K. Holliday, A. Chagneau, F. Claret,
T. Schäfer, T. Stumpf Dalton Transactions 2012, 41, (13). [7] G.K. Darbha, G.,
C. Fischer, J. Luetzenkirchen, T. Schäfer ES&T 2012, 46(17), 9378-9387. [8] F.
Claret, T. Schäfer, J. Brevet, P.E. Reiller ES&T 2008, 42, 8809. [9] F. Huber, F.
Enzmann, A. Wenka, M. Dentz, T. Schäfer J. Contam. Hydrol. 2012, 133, 40-52. |
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