1. School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, P.R. China
2. State Key Laboratory Cultivation Base for Gas Geology and Gas Control of Henan Province, Jiaozuo 454003, P.R. China
3. School of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454003, P.R. China