1. College of Geology and Environment, Xi’an University of Science and Technology, Xi’an, China
2. Institute of Engineering and Technology, PetroChina Coalbed Methane Co., Ltd., Xi’an, China
3. School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi’an, China
4. College of Chemistry and Chemical Engineering, Xi’an University of Science and Technology, Xi’an, China