1. Department of Environmental Engineering, School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, China
2. Department of Analytical Chemistry, School of Chemical Engineering, Lanzhou University of Arts and Science, Lanzhou, PR China
3. Lanzhou Center for Oil and Gas Resource, Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou, PR China