1. Applied Physical and Analytical Chemistry Laboratory, Department of Inorganic Chemistry, Faculty of Science, University of Yaoundé I, Cameroon
2. Solid Mineral Chemistry, Applied Chemistry and Environment Laboratory, Faculty of Sciences, Mohammed First University, Oujda, Morocco
3. UR Argile, Géochimie et Environnement Sédimentaires (AGEs), Département de Géologie, University of Liège, Liège, Belgium