1. School of Molecular Sciences, Arizona State University, Tempe, AZ 85297-1604, USA
2. NSF Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, AZ 85287-3005, USA
3. Department of Civil Engineering, University of North Dakota, Grand Forks, ND 58202-8115, USA