LCH - Laboratory of Radiochemistry and Environmental Chemistry

The Laboratory of Radiochemistry and Environmental Chemistry (LCH) at the Paul Scherrer institute is part of a joint research unit with the University of Bern, where the head of LCH holds the only chair of radiochemistry in Switzerland.

One of the main mission of LCH is to disseminate the knowledge and skills required to handle radioactive materials to a large number of doctoral and master students. The LCH holds six integrating research groups focusing on radiochemical basic and applied science.

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News

12 April 2013

Annual Report 2012

LCH proudly presents:
The Annual Report 2012
Contact: Andreas Türler
Download Internet
Search & Download Intranet

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6 March 2013

Focus on Chemistry in Snow

Our research on chemistry on ice and snow was recently covered in the Media
An article in the Neue Zürcher Zeitung (NZZ) View at NZZ
A comment in Nature View at Nature
A podcast from Nature Listen at Nature
A note in Horizonte Read at SNF
An interview Read at PSI

Contact: Thorsten Bartels-Rausch
Contact: Markus Ammann

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15 October 2012

Research Portrait in "Fenster zur Forschung"

Anja Eichler and her research are presented in the current PSI publication "Fenster zur Forschung".
Contact: Anja Eichler
More Info: Download pdf

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Recent Scientific Highlight

Effect of surface charge density on the affinity of oxide nanoparticles for the vapor–water interface

Research Department Biology and Chemistry (BIO), Surface Chemistry Group, Head Markus Ammann. Using in-situ X-ray photoelectron spectroscopy at the vapor-water interface, the affinity of nanometer-sized silica colloids to adsorb at the interface is shown to depend on colloid surface charge density. In aqueous suspensions at pH 10 corrected Debye-Hückel theory for surface complexation calculations predict that smaller silica colloids have increased negative surface charge density that originates from enhanced screening of deprotonated silanol groups by counterions in the condensed ion layer. The increased negative surface charge density results in an electrostatic repulsion from the vapor-water interface that is seen to a lesser extent for larger particles that have a reduced charge density in the XPS measurements. We compare the results and interpretation of the in-situ XPS and corrected Debye-Hückel theory for surface complexation calculations with traditional surface tension measurements. Our results show that controlling the surface charge density of colloid particles can regulate their adsorption to the interface between two dielectrics.

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Recent Publications

• Effect of surface charge density on the affinity of oxide nanoparticles for the vapor–water interface MA Brown, N Duyckaerts, AB Redondo, I Jordan, F Nolting, A Kleibert, M Ammann, HJ Wörner, JA van Bokhoven and Z Abbas
  Langmuir 29, 5023-5029 (2013).
  DOI: 10.1021/la4005054  
• Temporal variations of perfluoroalkyl substances and polybrominated diphenyl ethers in alpine snow T Kirchgeorg, A Dreyer, J Gabrieli, N Kehrwald, M Sigl, M Schwikowski, C Boutron, A Gambaro, C Barbante and R Ebinghaus
  Environmental Pollution 178, 367-374 (2013).
  DOI: 10.1016/j.envpol.2013.03.043  
• Adsorption characteristics of ²¹⁰Pb, ²¹⁰Po and ⁷Be onto micro-particle surfaces and the effects of macromolecular organic compounds W Yang, L Guo, C-Y Chuang, D Schumann, M Ayranov and PH Santschi
  Geochimica et Cosmochimica Acta 107, 47-64 (2013).
  DOI: 10.1016/j.gca.2012.12.039