1. 1 Valahia University from Targoviste , Doctoral School of Materials Engineering , Targoviste , Romania
2. 2 National Institute for Research and Development in Chemistry and Petrochemistry – ICECHIM , 202 Splaiul Independentei, 060021 , Bucharest , Romania
3. 3 Valahia University from Targoviste , Institute of Multidisciplinary Research for Science and Technology , Targoviste , Romania