Montag, 24. Juni 2013, 16:30 - 18:00 iCal
Analysis, fate, and effects of single-walled carbon nanotubes in the aquatic environment
Current Issues in Environmental Geosciences II
Aktuelle Themen in den Umweltgeowissenschaften II
Eberhard Clar-Saal (2B 204), Fakultät für Geowissenschaften, Geographie und Astronomie
Althanstrasse 14, UZA II, 1090 Wien
Seminar, Workshop, Kurs
Single-walled carbon nanotubes (SWNTs) are filamentous manifestations of a repeating aromatic carbon structure formed into an open cylinder. Because of their unique physicochemical properties and potential for large-scale commercialization, concerns have emerged over potential adverse effects of nanomaterials such as SWNTs in the aquatic environment. These concerns include direct toxicity to aquatic organisms as well as potential effects on distribution of hydrophobic organic contaminants (HOC) through adsorptive sequestration. This presentation will focus on a summary of work performed to date in my laboratory aimed at elucidating the analytical chemistry and environmental fate & effects of these novel contaminants in aquatic systems. One of the most challenging problems we face in assessing fate of SWNT in the aquatic environment is the lack of reliable analytical methods for detecting these species in complex environmental samples. Near Infrared fluorescence (NIRF) spectroscopy has advanced as a highly selective and information-rich technique for sensitive detection and structural characterization of SWNT materials. We have combined asymmetric flow field flow fractionation (A4F) with NIRF spectroscopy as a promising tool for determination of SWNT in the environment. The combination of these two techniques allows trace (part-per-billion) detection and quantitation of SWNT in aquatic systems and biota. In laboratory studies, we have observed that SWNTs can be stabilized in colloidal solutions by coating with natural organic matter, but that this stability is highly dependent on solution ionic strength. Increasing ionic strength leads to aggregation of SWNTs as well as deposition of these materials to suspended particulates. In addition, SWNTs adsorb HOCs strongly from aqueous solutions. Taken together, these results indicate that these carbon nanomaterials will associate strongly with sediments in aquatic systems, where they may become important in modulating fate of co-occurring molecular contaminants. Results of laboratory microcosm and field mesocosm studies are fully consistent with these findings. Toxicity assays indicate that while purified SWNTs themselves are relatively non-toxic to benthic deposit feeders, their carbonaceous manufacturing byproducts may cause deleterious effects to these organisms. The implications of our findings will be interpreted in context of potential ecotoxicological hazards posed by contamination of aquatic systems with SWNTs.
Veranstalter
Prof. Lee Ferguson, Duke University, NC, USA
Kontakt
Vesna Micic Batka
Department of Environmental Geosciences
Environmental Geosciences Group
01/427753372
vesna.micic@univie.ac.at
Erstellt am Donnerstag, 06. Juni 2013, 11:29
Letzte Änderung am Mittwoch, 19. Juni 2013, 12:54