Abstract
Environmental toxic metal contamination remediation and prevention is an ongoing issue. Graphene oxide is highly sorptive for many heavy metals over a wide pH range under different ionic strength conditions. We present x-ray absorption fine structure (XAFS) spectroscopy results investigating the binding environment of Pb(II), Cd(II) and U(VI) ions onto multi-layered graphene oxide (MLGO). Analysis indicates that the dominant sorption mechanism of Pb to MLGO changes as a function of pH, with increasing inner sphere contribution as pH increases. In contrast, the sorption mechanism of Cd to MLGO remains constant under the studied pH range. This adsorption mechanism is an electrostatic attraction between the hydrated Cd+2 ion and the MLGO surface. The U(VI), present as the uranyl ion, changes only subtly as a function of pH and is bound to the surface via an inner sphere bond. Knowledge of the binding mechanism for each metal is necessary to help in optimizing environmental remediation or prevention in filtration systems.
| Original language | English |
|---|---|
| Article number | 012094 |
| Journal | Journal of Physics: Conference Series |
| Volume | 712 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2016 |
| Externally published | Yes |
| Event | 16th International Conference on X-Ray Absorption Fine Structure, XAFS 2015 - Karlsruhe, Germany Duration: Aug 23 2015 → Aug 28 2015 |
Funding
MRCAT is supported by the U.S. Department of Energy and the member institutions. Use of the APS was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A.R.S. wishes to thank the staff at MRCAT, B. Mishra and K. Werellapatha for beamline support and useful conversations. Experiment used instrumentation at the Center for Environmental Science and Technology (CEST) at the University of Notre Dame. This research was supported, in part, by a fellowship to TAD from the Arthur J. Schmitt Foundation. The authors also wish to thank the two anonymous reviewers for their excellent comments.