1. College of Chemistry Taiyuan University of Technology Taiyuan 030024 P. R. China
2. College of Chemical Engineering and Technology Taiyuan University of Technology Taiyuan 030024 P. R. China
3. College of Environment Science and Engineering Taiyuan University of Technology Jinzhong 030600 P. R. China
4. Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization Taiyuan 030024 P. R. China