Enhanced Sorption of Radionuclides by Defect-Rich Graphene Oxide


Enhanced Sorption of Radionuclides by Defect-Rich Graphene Oxide

Boulanger, N.; Kuzenkova, A. S.; Iakunkov, A.; Romanchuk, A. Y.; Trigub, A. L.; Egorov, A. V.; Bauters, S.; Amidani, L.; Retegan, M.; Kvashnina, K.; Kalmykov, S. N.; Talyzin, A. V.

Extremely defect graphene oxide (dGO) is proposed as an advanced sorbent for treatment of radioactive waste and con-taminated natural waters. dGO prepared using a modified Hummers oxidation procedure, starting from reduced graphene oxide (rGO) as a precursor, shows significantly higher sorption of U(VI), Am(III) and Eu(III) compared to standard gra-phene oxides (GO). Earlier studies revealed the mechanism of radionuclide sorption related to defects in GO sheets. There-fore, explosive thermal exfoliation of graphite oxide was used to prepare rGO with large number of defects and holes. De-fects and holes are additionally introduced by Hummers oxidation of rGO thus providing extremely defect-rich material. Analysis of characterization by XPS, TGA, FTIR shows that dGO oxygen functionalization is predominantly related to de-fects, such as flake edges and edge atoms of holes, whereas standard GO exhibits oxygen functional groups mostly on the planar surface. The high abundance of defects in dGO results in a 15-fold increase in sorption capacity of U(VI) compared to standard Hummers GO. The improved sorption capacity of dGO is related to abundant carboxylic groups attached hole edge atoms of GO flakes as revealed by synchrotron-based extended X-ray absorption fine structure (EXAFS) and high-energy resolution fluorescence detected X-Ray absorption near edge structure (HERFD-XANES) spectroscopy.

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Publ.-Id: 31261