1. Key Laboratory of Water Pollution Treatment & Resource Reuse, Hainan Normal University, Haikou, Hainan 571158, P. R. China
2. College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou, Hainan 571158, P. R. China
3. Division of Sustainable and Environmental Engineering, Graduate School of Engineering, Muroran Institute of Technology, 27-1, Mizumoto-cho, Muroran, Hokkaido, 050-8585, Japan