1. Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, College of Science, Hainan University, Haikou 570228, China
2. School of Chemical Engineering and Technology, Hainan University, Haikou 570228, P. R. China
3. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China