1. School of Chemical and Biomedical Engineering; Nanyang Technological University; Singapore 637459 Singapore
2. College of Environmental Science and Engineering; Hunan University; Changsha 410082 P. R. China
3. School of Chemical Engineering; Shandong University of Technology; Zibo 255049 P. R. China
4. Singapore Membrane Technology Center; Nanyang Environment and Water Research Institute; Nanyang Technological University; Singapore 639798 Singapore