1. UNESCO-UNISA Africa Chair in Nanoscience and Nanotechnology College of Graduates Studies, University of South Africa, Muckleneuk Ridge, Pretoria 392, South Africa
2. Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, P.O. Box 722, Somerset West 7129, Western Cape, South Africa
3. Nanotechnology and Water Sustainability Research (NanoWS) Unit, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709, South Africa
4. Department of Agriculture and Animal Health, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X6, Florida 1710, South Africa
5. School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg 3201, South Africa