1. Environmental Protection and Energy Saving Center, China Waterborne Transport Research Institute, No. 8 Xitucheng Road, Haidian District, Beijing 100088, P. R. China
2. Department of Chemical Processes and Environments, The University of Kitakyushu, 1-1 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0135, Japan
3. School of the Earth Sciences and Resources, China University of Geosciences, No. 29 Xueyuan Road, Haidian District, Beijing 100083, P. R. China