Study Of UiO-66-based Photocatalyst For Uranium Enrichment And Separation In Fluorinated Uranium Containing Wastewater

Nuclear power is expected to remove traditional fossil power for the advantage of high power efficient and none carbon dioxide production.While,a lot of fluorinated uranium contained wastewater will be produced in the process of nuclear fuel production.For the Uranium have strong toxicity and enduring radioactivity,it has great harmful for environment and human body.In natural environment,uranium was exist as two stable species:hard-migrate U（IV）and easy-migrate U（VI）.In fluorinated uranium contained wastewater,stable F-U bond will be formed by the coordination of fluorion and uranyl ion.So,separating uranium in fluorinated uranium contained wastewater efficiently is of significant mining to nuclear power sustainable development.Reducing easy-migrate U（VI）to hard-migrate U（IV）in water solution is an efficient method in separating uranium in fluorinated uranium contained wastewater system.For the advantage of cleaner,efficient,and no extra energy required,photocatalystic method is expected to extract U（VI）in fluorinated uranium contained wastewater efficiently.In large kinds of photocatalyst,metal-organic framework（MOF）have its inborn advantage of other photocatalyst for the high porosity and surface area.While common MOFs materials were lack of U（VI）special confinement sites and high recombination rate of electron and holes limiting the efficient of U（VI）separation.This paper used Ui O-66 as photocatalyst and developed two photocatalysts（Mn O_x/NH₂-Ui O-66 and Mn O_x/NH₂-Ui O-66-r GO aerogel）by the method of coupling surface functionalized groups and loading cocatalyst,achieving efficient U（VI）separation in fluorinated uranium contained wastewater.The main research contents of this paper are as follows:（1）Aiming at the difficulty of U（VI）reduction in fluorinated uranium contained wastewater which resulting by the coordination of fluorion and uranyl ion,we synthesized Mn O_x/NH₂-Ui O-66 photocatalyst by introducing amino group as U（VI）special confinement sites and loading Mn O_xas oxidation cocatalyst achieved efficient U（VI）removal in fluorinated uranium contained wastewater system.By analysing the XPS spectra,the N characteristic peak were shifted after photocatalystic,indicating amino groups were served as the U（VI）confinement sites.The concentration of·O₂^-and the oxygen evolution rate of the materials were significantly promoted after loading Mn O_x,indicating Mn O_xis able to caught holes efficiently and served as the water oxidation sites.When the catalyst concentration is 0.5 g/L,simulate sunlight irradiation for 120 min,and the mole concentration of U:F is 1:20,the U（VI）removal ratio of Mn O_x/NH₂-Ui O-66 achieved 81.3%.Similarly,under the condition of different U（VI）concentration,multiple cations coexist,and wide p H value,Mn O_x/NH₂-Ui O-66 kept excellent U（VI）removal capability.（2）Mn O_x/NH₂-Ui O-66-r GO aerogel（M/Ui O-r GO）were successfully synthesized,which was used Ui O-66 as main body,reduced graphene oxide as frame,and manganese oxide as cocatalyst.The synthesized M/Ui O-r GO were used to separate U（VI）from fluorinated uranium contained wastewater by photocaralystic.r GO were served as the frame materials and the cocatalyst which is able to catch electrons.Also,r GO provided a lot of confinement sites for U（VI）confinement.By analysing PL and PL-time spectra of the materials,r GO and Mn O_xwere able to catch the photogenerate electrons and holes which produced on NH₂-Ui O-66,respectively.In the simulate fluorinated uranium contained wastewater experiment,when the catalyst concentration is 0.25 g/L and the mole ratio of U:F is 1:20,M/Ui O-r GO is able to remove 78.6%of U（VI）in system after photocaralysis for 1 h.Additionally,M/Ui O-r GO have excellent cycling stability,and the U（VI）removal ratio is of 87.2%even after fifth cycle.In this paper,Ui O-66 were enhanced by coupling surface functionalized groups and loading cocatalyst Two photocatlysts were developed to separate uranium in fluorinated uranium contained wastewater,achieving efficient U（VI）in fluorinated uranium contained wastewater system.At the same time,this paper also provides theoretical guidance for the efficient separating U（VI）in fluorinated uranium contained wastewater system.