1. Department of Chemical Engineering, Faculty of Engineering, Universitas Sriwijaya, Indralaya 30662 South Sumatra, Indonesia
2. Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
3. Department of Environmental Science, Faculty of Science and Natural Resources, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia