1. Department of Chemical Engineering, College of Environment and Chemical Engineering, Xi'an Polytechnic University, Xi'an, Shaanxi, China.
2. Department of Environmental Engineering, State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, China.
3. Department of Civil Engineering, School of Civil Engineering, North Minzu University, Yinchuan, China.