1. College of Engineering, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
2. Nanyang Environment and Water Research Institute, Residues and Resource Reclamation Center, 1 Cleantech Loop, Cleantech, Singapore 637141, Singapore
3. Laboratory of Molecular Science and Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, FI-20500 Turku, Finland