In Situ Chemical Transformations of Silver Nanoparticles along the Water-Sediment Continuum.
In: Environmental Science & Technology, Jg. 49 (2015-01-06), Heft 1, S. 318-325
academicJournal
Zugriff:
In order to accurately assess the potential environmental risk posed by silver nanoparticles (Ag-NPs), their transformation and fate must be investigated in natural systems. This has proven to be very challenging due to the difficulties encountered in retrieving/analyzing NPs dispersed in complex and heterogeneous environmental matrices at relevant (i.e., low) concentrations. In this study, we overcame this challenge by immobilizing functionalized Ag-NPs onto plasma polymerized solid substrates to form "nano in situ deployment devices" (nIDDs). This method allowed us to retrieve and analyze the Ag-NPs after 48 h of direct exposure in freshwater-sediment and saltwater-sediment environments. The type and extent of Ag-NPs transformation was expected to vary along the water-sediment continuum as sediments typically contain steep gradients in solute concentrations and redox potential. To trace the distribution of redox sensitive elements (e.g., Fe, Mn), Diffusive Equilibration in Thin-films (DET) devices were inserted into the sediments alongside the nIDDs. Chemical transformation of the immobilized Ag-NPs across the water-sediment continuum was investigated after retrieval by synchrotron radiation X-ray Absorption Spectroscopy. Linear combination fitting of Ag K-edge X-ray absorption spectra indicated that the chemical transformations of Ag-NPs in both freshwater and saltwater sediments were strongly affected by the redox conditions over the investigated range. Silver bound to reduced sulfur was the principal product of Ag-NP transformations but different extents of transformation were observed for Ag-NPs exposed to different depths in the sediment. These field results add important insights about the transformation of Ag-NPs in heterogeneous environments. [ABSTRACT FROM AUTHOR]
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In Situ Chemical Transformations of Silver Nanoparticles along the Water-Sediment Continuum.
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Autor/in / Beteiligte Person: | Khaksar, Maryam ; Jolley, Dianne F. ; Sekine, Ryo ; Vasilev, Krasimir ; Johannessen, Bernt ; Donner, Erica ; Lombi, Enzo |
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Zeitschrift: | Environmental Science & Technology, Jg. 49 (2015-01-06), Heft 1, S. 318-325 |
Veröffentlichung: | 2015 |
Medientyp: | academicJournal |
ISSN: | 0013-936X (print) |
DOI: | 10.1021/es504395m |
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