1. Master Student, Dept. of Inorganic Chemical Technology, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu
2. Ph.D. Student, Dept. of Inorganic Chemical Technology, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu
3. Senior Teaching Assistant, Dept. of Environmental Engineering, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu
4. Associate Professor, Dept. of Inorganic Chemical Technology, Faculty of Technology and Metallurgy, Univ. of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia. E-mail: nht@tmf.bg.ac.yu