1. College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong 030600, Shanxi, P. R. China
2. Department of Environmental and Safety Engineering, Taiyuan Institute of Technology, Taiyuan 030018, Shanxi, P. R. China
3. Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, P. R. China