Ab Initio calculations were performed to model the sorption of uranyl pentahydrate (UO2(H2O)5) onto the carboxyl functional group of graphene oxide, and these calculations were compared with experimental batch sorption and FTIR spectra.  The models were utilized to characterize the sorption reactions in terms of energetics, changes in molecular geometry, and vibrational peak shifts.    The calculations performed used Gaussian09, the B3LYP functional, and 6-311++G(d,p) and LANL2DZ basis sets.  The modelling found sorption onto a carboxyl group oriented approximately parallel to the plane of the graphene sheet to be energetically favorable (?Esorption =  -113.4 kJ/mol).  The model for the parallel orientation showed that the uranyl asymmetric stretch vibrational peak shifted lower with sorption, from 1003 cm-1 to 934 cm-1.  Though the exact wavelengths do not match, this redshift is consistent with experimental results, where a shift in the uranyl asymmetric stretch from 937 cm-1 to 912 cm-1 was observed upon sorption.

Ab initio calculations and experimental studies of uranyl sorption to graphene oxide

248th National Meeting (2014)

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