1. 1College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, PR China
2. 2College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, PR China
3. 3The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, Guilin 541004, PR China
4. 4Hezhou University, Hezhou 542899, PR China