1. Department of Petrochemical Technology Lanzhou University of Technology Provincial Key Laboratory of Gansu Higher Education for City Environmental Pollution Control School of Chemistry Engineering Lanzhou City University. Lanzhou Yinchuan 730070 P.R. China
2. Provincial Key Laboratory of Gansu Higher Education for City Environmental Pollution Control School of Chemistry Engineering Lanzhou City University. Lanzhou 730070 P.R. China
3. Department of Petrochemical Technology Lanzhou University of Technology Lanzhou 730070 P.R.China