1. Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
2. International Iberian Nanotechnology Laboratory, Water Quality Group, Avenue Mestre Jose Veiga s/n, 4715-330 Braga, Portugal
3. Department of Chemistry, University of Fribourg, Chemin du Musee 9, 1700 Fribourg, Switzerland