title: Understanding the interactions of neptunium and plutonium ions with graphene oxide: scalar-relativistic DFT investigations.
abstract: Due to the vast application potential of graphene oxide (GO)-based materials in nuclear waste processing, it is of pivotal importance to investigate the interaction mechanisms between actinide cations such as Np(V) and Pu(IV, VI) ions and GO. In this work, we have considered four types of GOs modified by hydroxyl, carboxyl, and carbonyl groups at the edge and epoxy group on the surface, respectively. The structures, bonding nature, and binding energies of Np(V) and Pu(IV, VI) complexes with GOs have been investigated systematically using scalar-relativistic density functional theory (DFT). Geometries and harmonic frequencies suggest that Pu(IV) ions coordinate more easily with GOs compared to Np(V) and Pu(VI) ions. NBO and electron density analyses reveal that the coordination bond between Pu(IV) ions and GO possesses more covalency, whereas for Np(V) and Pu(VI) ions electrostatic interaction dominates the An-OG bond. The binding energies in aqueous solution reveal that the adsorption abilities of all GOs for actinide ions follow the order of Pu(IV) > Pu(VI) > Np(V), which is in excellent agreement with experimental observations. It is expected that this study can provide useful information for developing more efficient GO-based materials for radioactive wastewater treatment.
authors.affiliation: Key Laboratory of Nuclear Radiation and Nuclear Energy Technology and Key Laboratory For Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Qun-Yan
authors.initials: QY
authors.lastname: Wu
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Lan
authors.forename: Cong-Zhi
authors.initials: CZ
authors.lastname: Wang
authors.forename: Yu-Liang
authors.initials: YL
authors.lastname: Zhao
authors.forename: Zhi-Fang
authors.initials: ZF
authors.lastname: Chai
authors.forename: Wei-Qun
authors.initials: WQ
authors.lastname: Shi
mesh_terms: D006108:Graphite / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D009405:Neptunium / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D011005:Plutonium / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D007477:Ions; D010087:Oxides; D011005:Plutonium; D009405:Neptunium; D006108:Graphite