Sorption mechanisms of metals to graphene oxide

16th International Conference on X-ray Absorption Fine Structure

Showalter, Allison R.^1 ; Duster, Thomas A.^2 ; Szymanowski, Jennifer E.S.^2 ; Na, Chongzheng^2 ; Fein, Jeremy B.^2 ; Bunker, Bruce A.^1

Department of Physics, University of Notre Dame, Notre Dame

IN

46556, United States^1

Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame

IN

46556, United States^2

关键词: Adsorption mechanism;    Binding mechanisms;    Electrostatic attractions;    Environmental remediation;    Filtration systems;    Multi-layered graphene;    Sorption mechanism;    Strength condition;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012094/pdf
DOI  :  10.1088/1742-6596/712/1/012094

来源: IOP

【 摘 要 】

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+2ion 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.