1. College of Chemistry and Chemical Engineering, Hubei Polytechnic University, Huangshi 435003, P. R. China
2. Hubei Key Laboratory of Mine Environmental Pollution Control & Remediation, Hubei Polytechnic University, Huangshi 435003, P. R. China
3. Key Laboratory of Coal Conversion and New Carbon Materials of Hubei Province, College of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, P. R. China