Publications by authors named "Karsten Franke"

6 Publications

  • Page 1 of 1

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

Effect of glutamic acid on copper sorption onto kaolinite - Batch experiments and surface complexation modeling.

Chemosphere 2017 Jul 21;178:277-281. Epub 2017 Mar 21.

Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Permoserstr. 15, 04318 Leipzig, Germany. Electronic address:

High carbonate content of the European Kupferschiefer ore deposits is a challenge for acid copper leaching (pH ≤ 2). Therefore investigating the mobility behavior of Cu(II) under conditions related to an alternative, neutrophil biohydrometallurgical Cu(II) leaching approach is of interest. As glutamic acid (Glu) might be present as a component in the growth media, we studied its effects on the adsorption of Cu(II) onto kaolinite. The binary and ternary batch sorption measurements of Cu(II) and Glu onto kaolinite were performed in the presence of 10 mM NaClO as background electrolyte and at a pH range from 4 to 9. Sorption experiments were modeled by the charge-distribution multi-site ion complexation (CD-MUSIC) model by using single sorption site (≡SOH) and monodentate surface complexation reactions. Glu sorption on kaolinite is weak (<10%) and independent of pH. Furthermore, Glu slightly enhances the Cu(II) sorption at low pH but strongly hinders (up to 50%) the sorption at higher pH and therewith enhances copper mobility. The results of isotherms show that Cu(II)-Glu sorption onto kaolinite mimics the Freundlich model. The proposed CD-MUSIC model provides a close fit to the experimental data and predicts the sorption of Cu(II), Cu(II)-Glu and Glu onto kaolinite as well as the effect of Glu on Cu(II) mobility.
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http://dx.doi.org/10.1016/j.chemosphere.2017.03.073DOI Listing
July 2017

Mobility and transport of copper(II) influenced by the microbial siderophore DFOB: Column experiment and modelling.

Chemosphere 2017 Apr 12;173:326-329. Epub 2017 Jan 12.

Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Reactive Transport Division, Permoserstr. 15, 04318 Leipzig, Germany.

Acid Cu leaching from the European Kupferschiefer ore deposits is a challenge e.g. due to its high carbonate content. In this study, we investigated the transport behaviour of Cu under conditions related to a biohydrometallurgical leaching approach using neutrophil microorganisms in neutral to slightly alkaline solutions. We studied the effect of the microbial siderophore desferrioxamineB (DFOB) as a model leaching organic ligand on Cu mobility in column experiments with kaolinite. The results revealed that DFOB strongly enhances Cu mobility. The breakthrough of Cu occurs considerably earlier in the presence of DFOB than in the absence of the organic ligand. Furthermore, complete elution of Cu was observed at 5 pore volume exchanges faster compared to elution with deionized water. The established geochemical transport model shows good agreement with the experimental data and suggests a maximum efficiency at a Cu to DFOB molar ratio of 1:1. In addition, results of modelling revealed that in the absence of the ligand, a pH increase from 6.5 to 8.5 significantly retarded Cu breakthrough, whereas in the presence of DFOB, Cu breakthrough curves were nearly insensitive to pH changes and close to the breakthrough curve of a non-reactive tracer.
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http://dx.doi.org/10.1016/j.chemosphere.2017.01.058DOI Listing
April 2017

Convenient recycling and reuse of bombarded [¹⁸O]H₂O for the production and the application of [¹⁸F]F⁻.

Appl Radiat Isot 2015 Jul 11;101:44-52. Epub 2015 Mar 11.

Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Departments of Neuroradiopharmaceuticals and Production of Radiopharmaceuticals, POB 51 01 19, D-01314 Dresden, Germany.

The limited availability and the increasing demands of [(18)O]H2O force the reuse of bombarded [(18)O]H2O for the production of [(18)F]F(-) at least for the purposes of research. Therefore, inorganic and organic contaminants have to be removed from the [(18)O]H2O after bombardment. We present a simple, effective, easy-handling and reliable method of [(18)O]H2O purification including oxidation and distillation. The obtained recycled [(18)O]H2O had comparable quality to commercially distributed [(18)O]water. This was confirmed by a detailed comparison of produced radionuclides and their activities and the application of [(18)F]F(-) for the automated synthesis of [(18)F]fluspidine.
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http://dx.doi.org/10.1016/j.apradiso.2015.03.009DOI Listing
July 2015

Production of 85Sr at a 18MeV-cyclotron and purification for geochemical investigations.

Appl Radiat Isot 2014 Sep 12;92:22-4. Epub 2014 Jun 12.

Department of Neuroradiopharmaceuticals, Research Site Leipzig, Institute for Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Permoserstrasse 15, 04318 Leipzig, Germany.

The production of (85)Sr by irradiation of a Rb-target at a cyclotron was investigated. The purification of the radionuclide was performed by a Sr-selective resin. (85)Sr was separated in no-carrier-added aqueous solution with a recovery of 98% and a concentration up to 6.6MBq in 200µl.
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http://dx.doi.org/10.1016/j.apradiso.2014.06.001DOI Listing
September 2014

Radioiodination of humic substances via azocoupling with 3-[125I] iodoaniline.

Environ Sci Technol 2008 Jun;42(11):4083-7

Institute of Interdisciplinary Isotope Research, Permoserstrasse 15, 04318 Leipzig, Germany.

A new method is described for radiolabeling humic substances (HS) with iodine radioisotopes. The method radiolabels the electron-rich aromatic moieties of HS with the 3-[125I]iodobenzenediazonium ion via azocoupling. The method uses four steps: (i) 3-aminobenzenetrimethylstannane is synthesized and isolated by using a silica gel column, (ii) 3-[125I]iodoaniline is synthesized and isolated by HPLC, with radiochemical yields of up to 60%, (iii) 3-[125I]iodobenzenediazonium chloride is synthesized, and the reaction mixture from this step is used in step iv to radioiodinate HS with radiochemical yields of up to 95% (with reference to 3-[125I]iodoaniline). The advantage of this method is that it is selective radiolabeling, placing the radiolabel in a specific site (the 3-position of the phenyl ring) within HS molecules, which minimizes unwanted secondary chemical interactions. Investigations of the stability of the radiolabel and the effect of photoreductive dehalogenation showed that there was a negligible release of 125I. The production of radiolabeled HS using this method allows the sensitive detection of HS in laboratory and field studies. In addition, the method offers the possibility of using different iodine radioisotopes simultaneously in investigations using HS.
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http://dx.doi.org/10.1021/es702671vDOI Listing
June 2008