Publications by authors named "Heike Hildebrand"

4 Publications

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Elucidating the Role of Dissolution in CeO Nanoparticle Plant Uptake by Smart Radiolabeling.

Angew Chem Int Ed Engl 2017 06 19;56(26):7411-7414. Epub 2017 May 19.

Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Permoser Strasse 15, 04318, Leipzig, Germany.

The identification of major uptake pathways in plants is an important factor when evaluating the fate of manufactured nanoparticles in the environment and the associated risks. Using different radiolabeling techniques we were able to show a predominantly particulate uptake for CeO nanoparticles in contrast to a possible uptake in the form of ionic cerium.
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http://dx.doi.org/10.1002/anie.201702421DOI Listing
June 2017

Evaluating the cytotoxicity of palladium/magnetite nano-catalysts intended for wastewater treatment.

Environ Pollut 2010 Jan 23;158(1):65-73. Epub 2009 Sep 23.

Department of Environmental Engineering, UFZ - Helmholtz-Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany.

Palladium/magnetite nanoparticulate catalysts were developed for efficient elimination of halogenated organic pollutants from contaminated wastewater. Particle recovery from treated water can be ensured via magnetic separation. However, in worst-case scenarios, this catalyst removal step might fail, leading to particle release into the environment. Therefore, a toxicological study was conducted to investigate the impact of both pure magnetite and palladium/magnetite nanoparticle exposure upon human skin (HaCaT) and human colon (CaCo-2) cell lines and a cell line from rainbow trout gills (RTgill-W1). To quantify cell viability after particle exposure, three endpoints were examined for all tested cell lines. Additionally, the formation of reactive oxygen species was studied for the human cells. The results showed only minor effects of the particles on the tested cell systems and support the assumption that palladium/magnetite nano-catalysts can be implemented for a new wastewater treatment technology in which advantageous catalyst properties outweigh the risks.
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http://dx.doi.org/10.1016/j.envpol.2009.08.021DOI Listing
January 2010

Highly active Pd-on-magnetite nanocatalysts for aqueous phase hydrodechlorination reactions.

Environ Sci Technol 2009 May;43(9):3254-9

UFZ-Helmholtz-Centre for Environmental Research, Department of Environmental Technology, Permoserstrasse 15, 04318 Leipzig, Germany.

Nanoscale catalyst particles are already in focus as excellent tools in catalytic processes and intensive research is currently optimizing their performance. As known from nanosized metal particles, nanocatalysts have the potential of very high reaction rates due to their high specific surface areas and low mass transfer restrictions. In this study, we generated extremely active palladium catalysts on the basis of colloidal magnetic carriers. The most active catalyst contains only traces of Pd (0.15 wt %) on nanomagnetite as carrier. Pd-on-magnetite was successfully tested in batch experiments for the hydrodechlorination (HDC) of the chlorohydrocarbons trichloroethene (TCE) and chlorobenzene. For the HDC of TCE, second-order rate coefficients of approximately 1.6 x 10(4) L g(-1) min(-1) were measured. Such high activities have never been described before for Pd-containing catalysts in aqueous phase HDC reactions. The ferrimagnetism of the carrier enables a separation of the nanocatalyst from the treated water by means of magnetic separation. This allows the catalyst to be reused several times, which is an important advantage compared to other nanoscale catalytic systems such as pure Pd or Pd-on-Au colloids.
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http://dx.doi.org/10.1021/es802726vDOI Listing
May 2009

[Aspects of animal welfare and species protection in the international trade of ornamental fish and air transport to Germany].

Berl Munch Tierarztl Wochenschr 2005 May-Jun;118(5-6):177-85

Verhaltenskunde,Tierhygiene und Tierhaltung, Tierärztliche Fakultät, Ludwig-Maximilians-Universität München.

The number of ornamental fish kept in German aquariums is rising, but the supply of offspring is not sufficient to meet the needs of the fish enthusiasts. Therefore millions of ornamental fish from foreign countries are being imported to Germany. This provokes a number of new problems regarding the protection of species and the animals' welfare during transportation. For the assessment of the transport conditions, 1000 shipments of ornamental fishes were evaluated at the Rhein-Main-Airport Frankfurt, Germany. Water samples were taken from 100 shipments and were examined for anaesthetics. The results are disturbing: 41% of the shipments have total transportation times between 31-42 h resulting in an oxygen deficit in the transport bags (5.2%) and dead ornamental fish. Also damage of the transportation containers, high fish densities as well as drastic size differences amoung the fish in one transport bag were noticeable. In 99% of the cases, formal defects could be noted. The German association of pet stores has declared that fish belonging to three special fresh water families should not be kept in an aquarium, but 1 200 of such fish were imported. The HPLC analysis of the water samples revealed an additive. The non-declared anaesthetic 2-phenoxyethanol was present in all samples taken from shipments based out of Singapore. The results emphasize that improvements are urgently necessary in the control of the air transport and trade with Ornamental fish.
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August 2005