First-principles Investigations Of Absorption Ability To Nuclear Waste With Graphene

Nuclear fuel cycle will produce a large amount of radioactive substance,which can pose long-tell risks to the human life if put the irradiated nuclear fuel under the deep ground,so the best way to dispose these radioactive substance is reprocessing technology.Separate uranium and plutonium can back into the reactor,some minor actinides and fission products also can separation and purification.Am and Cm belongs to typical minor actinides,they can binding H2O form coordination compounds in the water.Am(or Cm)is difficult to separate in the industrial and they are expensive in market value.Graphene is a planar-monolayer structure consisting of extraordinarily hexagonal sp2-bonded carbon rings,has excellent physical and chemical properties.Graphene used to remove radionuclides from radioactive solutions and demonstrated to be an effective adsorbent,and also have some studys on experiment like U and Pu.The oxygen-bearing groups on the graphene's surface can increase its hydrophilicity,so efficiently bind metal ions through sharing an electron pair of the oxygen atom.The first-principle calculations are used in this paper to estimate the structure and binding nuture of the[Am(H2O)8]3+/GO and[Cm(H2O)n]3+/GO compare the binding energy can give us the relationship of the different GO adsorption Am and Cm.The natural bond orbital can clear understanding of the bonding nuture of these two elements.In this paper,first we optimized the complexes formed between Am3+(or Cm3+)and graphene modified by oxygen-containing groups in gaseous phassand solvation effect respectiveiy,the binging nuture and bonding nuclear though gibbs free energy ?G and NBO analysis.The result show that GO can efficiently bind with Am+ and Cm3+.To examine the bingding ability of four oxygen-containing groups functionalized GO with uranyl ion,we investigate the binding energies of uranyl ion and GO in both the gas and aqueous phase together with the changes of the Gibbs free energy in solution ?G,the oxygen-containing groups is is sensitive to the adsorption abilities,and GO with amino functional group can separate Am and Cm effectively.In order to further study the bonding nature between GO and Am3+(or Cm3+),the bond orders investigated by NBO analysis.The result show that:GO can adsorb Am3+(or Cm3+)stablely because of the oxygen-bearing groups on the ligand can share an eletron pair of the oxygen atom,efficiently bind central metal ion,and form a covalent character.