1. Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education; China University of Mining & Technology; Xuzhou 221116 Jiangsu China
2. State Key Laboratory of High-efficiency Coal Utilization and Green Chemical Engineering; Ningxia University; Yinchuan 750021 Ningxia China
3. College of Chemistry and Chemical Engineering; Taiyuan University of Technology; Taiyuan 030024 Shanxi China
4. School of Chemistry and Chemical Engineering, Anhui Key Laboratory of Coal Clean Conversion and Utilization; Anhui University of Technology; Ma'anshan 243002 Anhui People's Republic of China