1. College
of Environmental Science and Engineering, Hunan University, Changsha 410082, P. R. China
2. Key
Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, P. R. China
3. Mobile
E-business 2011 Collaborative Innovation Center of Hunan Province, Hunan University of Commerce, Changsha 410205, China
4. School
of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore