1. Soils and Plant Nutrition Division, Tea Research Institute, Thalawakele, Sri Lanka;
2. Department of Engineering Technology, Faculty of Technology, University of Sri Jayewardenepura, Nugegoda, Sri Lanka;
3. Sri Lanka Institute of Nanotechnology, Homagama, Sri Lanka;
4. Department of Chemistry, University of Peradeniya, Peradeniya, Sri Lanka;
5. Department of Chemistry/Center for Advanced Materials Research, University of Sri Jayewardenepura, Nugegoda, Sri Lanka