1. Laboratory of Applied Environmental Chemistry, Department of Environmental Science, University of Eastern Finland, Patteristonkatu 1, FI-50100, Mikkeli, Finland, Department of Fundamental Material Science, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima, Okayama 700-8530, Japan, and Faculty of Technology, Lappeenranta University of Technology, Patteristonkatu 1, FI-50100 Mikkeli, Finland