The Theoretical Samulation Study Of UO₂²⁺ Complexation With Substituent Amidoximes

Uranium is the most important nuclear fuel.Recovery of uranium from seawater has been of great strategetic significance to the forthcoming uranium scarcity due to a large scale of utilization of uranium to alleviate the fossil energy crisis.The preparations of advanced,diverse adsorbents characterized by their excellent selectivity,large capacity,high adsorption rate and resistance to self-radiation of radioactive uranium have enabled the enrichment of uranium from seawater to solve the upcoming starvation of uranium.The theoretical calculations used in this paper are the Amsterdam density functional?ADF,Amsterdam Density Functional?simulation software.In the second chapter,the geometrical properties of the different substituents?-H,-F,-OH,-NH₂,-CF₃?amidoxime in the bis-ligand?2chelating mode with UO₂²⁺and VO+were calculated from the theoretical point of view at the PBE level Optimize structure,frequency and thermodynamic properties.And the results of the analysis of the data,the results show that amidoxime is indeed known in the literature,the uranium ion has a better adsorption performance.It was found that the double ligand chelation model was superior to the chelate mode of single ligand,and the selectivity to uranium was stronger than vanadium ion,which was different from the expected result.There is also the potential for further development of the amidoxime of the fluoro group,which is of reference to the design of subsequent adsorption ligands.In the second chapter,this study investigates the electronic effects of different substituents amidoximate ligands?-OH,-NH₂,-H,-F,-CF₃?bound to the UO₂²⁺,Fe³⁺,Ni²⁺,Co²⁺.Density functional theory calculations have been performed on a series of(UO₂²⁺,Fe³⁺,Ni²⁺,Co²⁺)-amidoximate derivatives to investigate their structural optimization and thermochemical properties.From analysis of bond energy,the data show that the basic trend to different substituents amidoxime chelated Fe³⁺ is the most stable relatively with UO₂²⁺chelation which is the most unstable.The calculation results of thermochemical properties indicates that AO adsorbent is easier to chelate with UO₂²⁺and Co²⁺,while AO-CF₃ adsorbent is the harder one to chelate.From the thermodynamic??G?analysis,different substituents amidoxime chelate on Co²⁺ and UO₂²⁺ion substitution sequence is-NH₂>-OH>-H>-F>-CF₃ which indicates the AO can be the first to chelate with Co²⁺,UO₂²⁺in the seawater.The theoretical results establish AO are more stable than other substituents amidoximate ligands and the Gibbs free energy of UO?AO?₂ are found to be-646.65kJ/mol in the ?² motif.So,this research work both on theoretical simulation method and on development of new adsorbent experimental study provides theoretical basis and experimental data.This work also plays certain significance in adsorption uranium in solution of using polymeritic fibric adsorbent.