1. School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal, Penang, Malaysia
2. Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
3. Department of Chemistry, University of Pretoria, Pretoria, South Africa
4. Department of Physical Sciences, Industrial Chemistry Programme, Landmark University, Omu-Aran, Nigeria