1. a Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
2. b Research Centre for Sustainable Process Technology, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
3. c Department of Civil Engineering, Politeknik Sultan Idris, Sungai Lang 45100, Sungai Air Tawar, Selangor, Malaysia
4. d Ralph E Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, AR 72701, USA