1. Faculty of Science; Laboratory of Analytical Chemistry; University of Yaoundé 1; Yaoundé Cameroon
2. Faculty of Civil and Industrial Engineering, Department of Chemical Engineering, Materials and Environment; Sapienza University of Rome; Rome Italy
3. Faculty of Civil and Industrial Engineering, Department of Civil, Building and Environmental Engineering; Sapienza University of Rome; Rome Italy
4. Laboratoire des Sciences des Procédés et des Matériaux; CNRS, Université Paris 13; Villataneuse France