1. Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576
2. Department of Environmental Science and Engineering, China University of Petroleum, P. R. China
3. Institute of Multifunctional Materials (IMM), Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071, P. R. China
4. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Dongying 257061, P. R. China