| Nuclear power is a clean and highly efficient energy that is regarded as a key component of contemporary energy systems.As an important nuclear energy strategic resource,uranium is the basic guarantee for the development of China’s nuclear industry.However,the uranium resources on China’s terrestrial ore are not unlimited,which can only maintain energy supply for the next 100 years.The ocean contains nearly 4.5 billion tons of uranium,which is about 1,000 times the amount of uranium deposited on land.Utilizing uranium resources in the oceans will solve the problem of shortages of nuclear energy supplies for centuries.However,the concentration of uranium ions in the ocean is only 3.3 ppb,and there are a large number of interference impurities.Effective and selective absorption of uranium is a difficult task.In order to overcome these major challenges,this paper uses the biomimetic technology and the modified phase separation strategy to prepare efficient,durable,and low-cost adsorbents,and characterizes the structure and morphology of materials by FT-IR,SEM,AFM and XPS.The uranium adsorption performances of the material under different adsorption conditions were also evaluated.More deteails are given as follows:（1）Highly efficient uranium adsorption by salicylaldoxime/polydopamine graphene oxide nanocompositesHere,inspired by the mussel foot proteins,a new method for rapid preparation of amidoxime-based uranium sorbents was developed in this study using dopamine as a functional reagent to synthesize salicylaldoxime/polydopamine modified reduced graphene oxide（RGo-PDA/oxime）via the polymerization of dopamine（DA）and simultaneous deposition of oxime.With the obviously decreased syntheses time from several days to 2 h,the maximum uranium adsorption capacity of the prepared RGo-PDA/oxime was up to1049 mg g-1,which was 3-16 times larger than those of the reported single PDA or oxime modified nanostructures.It demonstrated that the adsorption of uranium by RGo-PDA/oxime was fast and the adsorption process agreed well with the pseudo-second-order kinetics model and Langmuir isotherm equation with excellent adsorption selectivity and recycles.The outstanding sorption performance is attributable to the oxime that probably attached onto the upper surface of the samples due to the electrostatic repulsion between Go and salicylaldoxime as well as the effective combination between PDA and oxime molecules.Finally,given that DA can adhere on diverse surfaces,this rapid one-step method was used in five other nanostructures,and the prepared oxime/PDA modified materials exhibited improved uranium adsorption efficiency.These findings provided a way to fabricate oxime-functionalized nanostructures,which are promising candidates for uranium adsorption.（2）Robust flexible poly（amidoxime）porous network membranes for highly efficient uranium extraction from seawaterIn this study,modified aerosol porous network membranes（PAO PNMs）with high mechanical properties and adsorption capacity were prepared simply,quickly,and inexpensively using modified phase separation technology.The prepared PAO PNMs have excellent hydrophilicity,flexibility,tensile strength（16.98 MPa）,Young’s modulus（0.55GPa Young’s modulus）and porosity（3D porous network structure）;and show very good Its adsorption capacity,specificity and reproducibility,its uranium adsorption capacity is as high as 707±5.8 mg/g（in 8 ppm uranium spiked simulated seawater）and 9.35±0.47 mg/g（in natural seawater）,and recycled After 10 times,the adsorbent still has high adsorption efficiency.The kinetic model,XPS analysis,and Kd value confirmed the chemical affinity of the amidoxime group and uranyl in the adsorbent,and explained its adsorption mechanism.More importantly,this method can easily and inexpensively prepare porous PAO membranes.The high adsorption capacity and mechanical properties of PAO PNMs,simple and large-scale preparation techniques,show that they have broad application prospects in industrial seawater extraction of uranium. |
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