1. Faculty of Environmental Science and Engineering; Kunming University of Science and Technology; Kunming 650500 P. R. China
2. Department of Environmental and Chemistry Engineering; Chongqing Three Gorges University; Wanzhou 404100 Chongqing P. R. China
3. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization; Faculty of Land Resource Engineering; Kunming University of Science and Technology; Kunming 650093 P. R. China