1. School of Environmental Engineering, Henan University of Technology, Zhengzhou 450001, P. R. China
2. School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, P. R. China
3. Department of Physics, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00925, United States
4. Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00925, United States