1. Department of Materials and Energy Science and Engineering (MESE), School of Materials, Energy, Water and Environmental Sciences, Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania
2. Department of Chemistry, College of Natural and Mathematical Sciences, University of Dodoma, P.O. Box 338, Dodoma, Tanzania
3. School of Materials, Energy, Water and Environmental Sciences, Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania