1. Department of Process and Environmental Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, 90014 Oulu, Finland
2. Department of Technology, Central Ostrobothnia University of Applied Sciences, Talonpojankatu 2, 67100 Kokkola, Finland
3. Department of Chemistry, Faculty of Science, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland