1. College of Chemistry and Chemical EngineeringJinzhong University 199 Wenhua street, Yuci District, Jinzhong, Shanxi China 030619
2. College of Chemistry and Chemical EngineeringTaiyuan University of Technology 79 Yingze West Street, Wanbailin District, Taiyuan, Shanxi China 030024 Fax: +86-351-6018528
3. Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi ProvinceTaiyuan University of Technology 79 Yingze West Street, Wanbailin District, Taiyuan, Shanxi China 030024