1. School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan, Hubei 430070, China
2. Department of Chemistry, University of Connecticut, U-3060, 55 N. Eagleville Road, Storrs, Connecticut 06269, United States
3. Institute of Materials Science, University of Connecticut, U-3136, 97 N. Eagleville Road, Storrs, Connecticut 06269, United States