1. Department of Hydrosilicates, Institute of Inorganic Chemistry, Slovak Academy of Sciences, 845 36 Bratislava, Slovakia
2. Department of Chemistry, Faculty of Education, J. Selye University, 945 01 Komárno, Slovakia
3. Laboratory of Interfaces and Nanosized Systems, Institute of Chemistry, ELTE Eötvös Loránd University, H-1117 Budapest, Hungary
4. Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia