1. State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry & Chemical Engineering, Ningxia University, Yinchuan 750021, P. R. China
2. Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
3. Ningxia Academy of Metrology & Quality Inspection, National Quality Supervision and Inspection Center for Coal and Coal Chemical Products (Ningxia), Yinchuan 750200, P. R. China