1. Shanxi Key Laboratory of Compound Air Pollutions Identification and Control, College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
2. Key Laboratory of Coal Science and Technology, Ministry of Education, College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan 030024, P. R. China
3. Xi’an North Huian Chemical Industries Co. Ltd, Xi’an 710302, P. R. China
4. College of Chemistry and Chemical Engineering, Shaanxi Key Laboratory of Chemical Reaction Engineering, Yan’an University, Yan’an 716000, P. R. China