1. School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430070, P. R. China
2. Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Saltlakes, Chinese Academy of Sciences, Xining 810008, P. R. China
3. Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of Saltlakes, Xining 810008, P. R. China
4. College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China