1. Faculty of Applied Sciences, Coal and Biomass Energy Research Group, Universiti Teknologi MARA, Arau Campus, Arau, Perlis 02600, Malaysia, Tel. , Tel. , Tel.
2. Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor 40450, Malaysia
3. Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7 N 5C9, Canada, Tel.