A copper-based metal organic framework material, a preparation method and application thereof

Abstract

The application relates to a copper-based metal organic framework material, a preparation method and application thereof, and has a chemical formula of Cu2(TTB) 0.5 , belongs to a monoclinic system, a space group is C 2 / c, and has a non-porous dense-packed three-dimensional structure. The preparation method comprises the following steps: placing H4TTB and CuCN in an organic solvent containing an alkaline compound and an additive, heating to 150-170 DEG C, and performing a solvothermal reaction for 2-4 days to obtain the copper-based metal organic framework material. A system for electrochemically extracting uranium and synergistically degrading organic matters is an H-type electrolytic cell, which comprises a cathode chamber and an anode chamber separated by an ion exchange membrane, the cathode chamber is provided with a cathode, and the anode chamber is provided with an anode, and the cathode comprises the copper-based metal organic framework material. The Cu2(TTB) 0.5 is innovatively combined with the H-type electrolytic cell system, and the electrocatalytic extraction of uranium and the degradation of organic pollutants can be realized for the uranium-containing wastewater.

Description

Technical Field

[0001] This invention relates to the technical field of metal-organic framework materials and electrocatalysis, and more specifically to a copper-based metal-organic framework material, its preparation method, and its application. Background Technology

[0002] Nuclear energy has been widely recognized as a key transitional energy source to replace fossil fuels. Uranium is widely used as the primary fuel in nuclear reactors, but it currently mainly comes from natural uranium ore. However, natural uranium ore reserves are limited, and uranium-containing wastewater is generated in nuclear industry processes such as nuclear fuel production and spent fuel reprocessing. If uranium can be efficiently recovered from this wastewater and reused as a resource, a closed-loop cycle of uranium resources can be constructed, effectively reducing dependence on natural uranium ore, extending the uranium resource supply cycle, and achieving sustainable development of nuclear energy.

[0003] In recent years, metal-organic frameworks (MOFs), after modification with functional groups such as amine oxime, amino, and carboxyl groups, have been widely used in uranium extraction from seawater due to their large specific surface area and abundant adsorption sites. The main extraction methods are physical and chemical adsorption. However, in the actual treatment of uranium-containing wastewater generated by the nuclear industry, these porous MOFs face several bottlenecks: low uranium concentration in the wastewater system, slow uranyl ion diffusion rate, and intense ion competition caused by a large number of coexisting ions. Furthermore, the porous structure is prone to pore blockage, limiting uranium extraction efficiency and adsorption capacity, making it difficult to meet the complex needs of nuclear wastewater treatment. In contrast, electrocatalytic uranium reduction technology, with its faster adsorption kinetics and larger adsorption capacity, has become a promising approach for improving the uranium extraction efficiency of hexavalent uranium (U₂O₃). VI Potential strategies for improving extraction efficiency and rate are gradually becoming a research focus in the field of uranium-containing wastewater treatment.

[0004] In the daily operation and maintenance of nuclear facilities, the cleanliness of metal equipment surfaces is crucial to ensuring equipment safety and radiation protection effectiveness. Residual contaminants such as oil stains and metal oxides can accelerate equipment corrosion, damage the integrity of sealing structures, and even potentially trigger safety accidents such as nuclear leaks. Diethylene glycol dimethyl ether (DME) is a commonly used reagent for cleaning precision components in the nuclear industry due to its excellent solubility, chemical stability, and corrosion resistance. However, its strong chemical stability and resistance to oxidation by traditional chemical reagents make it a difficult-to-degrade organic pollutant, posing a significant challenge to the treatment of organic wastewater from the nuclear industry. More importantly, the wastewater actually generated by the nuclear industry is mostly a complex system in which uranyl ions and DME coexist. The pollutants easily form stable colloids or complexes, which not only significantly increases the difficulty of separating uranium from organic pollutants but may also enhance the migration of radionuclides and heavy metals, leading to potential secondary pollution risks. Currently, research on the degradation of diethylene glycol dimethyl ether (DGE) is still in its infancy. Existing electrochemical uranium extraction processes face three major technical challenges when treating complex radioactive wastewater containing high concentrations of DGE: First, traditional electrocatalytic uranium extraction materials are primarily porous, resulting in insufficient chemical and electrochemical stability in complex electrolysis environments, leading to structural collapse and catalytic activity degradation. Second, DGE and its degradation intermediates in the wastewater easily poison the cathode catalytic sites, strongly inhibiting the reduction reaction of uranium ions and causing a significant decrease in uranium extraction efficiency. Third, traditional electrolysis systems do not effectively isolate the anode and cathode regions, allowing the electrochemical reduction products of uranium (insoluble precipitates) to react with intermediates generated during anode degradation and redissolve, resulting in poor reliability and low efficiency in the uranium extraction process. Summary of the Invention

[0005] To address the problems of poor stability, high concentrations of organic matter inhibiting uranium extraction efficiency, and the inability to synergistically achieve uranium extraction and organic pollutant degradation in existing electrochemical uranium extraction materials, this invention aims to provide a copper-based metal-organic framework material, its preparation method, and its applications.

[0006] The copper-based metal-organic framework material according to the present invention has the chemical formula Cu2(TTB). 0.5 It belongs to the monoclinic crystal system, with space group C2 / c, and exhibits a three-dimensional structure with no pores and close packing.

[0007] In a preferred embodiment, Cu2(TTB) 0.5 The unit cell parameters are: a = 16.1176(11) Å, b = 8.8433(5) Å, c = 9.9041(6) Å, α = γ = 90 o , β=98.854(2) o V=1394.84(15)Å 3 .

[0008] According to the preparation method of the copper-based metal-organic framework material of the present invention, the method includes placing H4TTB and copper salt in an organic solvent containing alkaline compounds and additives, heating to 150~170°C for a solvothermal reaction for 2~4 days to obtain the copper-based metal-organic framework material.

[0009] In a preferred embodiment, the copper salt is CuCN, the alkaline compound is ammonia, the additive is ammonium fluoride, and the organic solvent is N,N-dimethylformamide and ethanol.

[0010] In a preferred embodiment, the molar ratio of H4TTB to CuCN is 1:3.5 to 1:4.5, the volume ratio of N,N-dimethylformamide to ethanol is 0.8 to 1:1 to 1.2, and the volume ratio of N,N-dimethylformamide to ammonia is 1 to 1.4:1 to 2.0.

[0011] The application of the copper-based metal-organic framework material according to the present invention in the preparation of electrode catalysts for the electrochemical extraction of uranium from aqueous solutions.

[0012] The system for electrochemical extraction of uranium and synergistic degradation of organic matter according to the present invention is an H-type electrolytic cell, comprising a cathode chamber and an anode chamber separated by an ion exchange membrane, wherein a cathode is disposed in the cathode chamber and an anode is disposed in the anode chamber, and the cathode comprises the aforementioned copper-based metal-organic framework material.

[0013] In a preferred embodiment, the ion exchange membrane is an anion exchange membrane, the cathode is made by loading the copper-based metal-organic framework material onto a conductive substrate, and the anode is a platinum sheet.

[0014] The method for systematic electrochemical extraction of uranium and synergistic degradation of organic matter according to the present invention comprises the following steps: S1, adding wastewater containing uranyl ions and organic pollutants to the cathode chamber and the anode chamber; S2, adding an electrolyte to the wastewater for electrocatalytic reaction; S3, applying a potential of -1.3V to -1.9V relative to the reference electrode to the cathode for constant potential electrolysis; wherein, during the electrolysis process, the uranyl ions are reduced to insoluble deposits on the cathode surface, while the organic pollutants are degraded in the anode region.

[0015] In a preferred embodiment, the Ag / AgCl electrode is used as a reference electrode, the electrolyte is sodium sulfate, and the organic pollutant is one or more selected from diethylene glycol dimethyl ether, 1-fluoro-1,1-dichloroethane, 1,1-dichloroethane, and dichloromethane. The concentration of diethylene glycol dimethyl ether in the wastewater to be treated is 0~100 g·L⁻¹. -1 The pH value of the wastewater to be treated is 1.0~8.0, and the concentration of uranyl ions in the wastewater to be treated is 0~100 mg·L⁻¹.-1 .

[0016] This invention utilizes the dense and stable MOF material Cu2(TTB) 0.5 Innovatively combined with a membrane separation H-type electrolytic cell system, even at concentrations up to 100 g·L⁻¹ -1 In the presence of diethylene glycol dimethyl ether, the effect on 100 mg·L⁻¹ -1 The uranium-containing wastewater can achieve complete electrocatalytic extraction of uranium (>99%) within 60 minutes, overcoming the traditional bottleneck of high-concentration organic matter strongly inhibiting uranium extraction; thanks to Cu2(TTB). 0.5 The inherently dense and stable structure of the material ensures that the cathode catalyst maintains its structural integrity over a wide pH range (1.0-8.0) and under long-term electrolysis conditions. After 10 consecutive cycles, the uranium extraction efficiency shows no significant decline (all >96.4%), solving the key problem of easy deactivation of crystalline catalytic materials. The membrane separation design of the H-type cell prevents the diffusion of toxic organic degradation intermediates (such as formic acid) generated at the anode into the cathode chamber, causing the redissolution of uranium crystals deposited at the cathode. On the other hand, it promotes the deep mineralization of organic matter at the anode. Simultaneously, the electrolysis of water in the cathode region creates a locally strong alkaline environment, accelerating the pH-driven uranium deposition process. This achieves efficient enrichment and separation of uranium resources at the cathode end and mineralization and volume reduction of organic wastewater at the anode. By further exchanging the electric field direction, the radioactive organic wastewater is ultimately deactivated and purified to meet emission standards. The material also withstands various common competing cations (such as Na+). + Ca 2+ Co 2+ Ni 2+ Al 3+ Fe 3+ ) and anions (such as F) − Cl − ,Br − I − NO3 − CO3 2− Even with the coexistence of these components, the system can still maintain a high selectivity for uranium extraction (efficiency > 85%), indicating that it has good adaptability and robustness to real complex wastewater components. Attached Figure Description

[0017] Figure 1 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 Coordination environment diagram of copper atoms in the material.

[0018] Figure 2 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 Coordination environment diagram of the organic ligands in the material.

[0019] Figure 3The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 Three-dimensional crystal structure diagram of the material.

[0020] Figure 4 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 A three-dimensional spatial filling diagram of the material.

[0021] Figure 5 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 X-ray powder diffraction pattern of the material.

[0022] Figure 6 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 PXRD overlay images of the material after immersion in aqueous solutions of different pH values ​​for 24 hours and after irradiation with β and γ rays.

[0023] Figure 7 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 Thermogravimetric analysis diagram of the material.

[0024] Figure 8 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 Nitrogen adsorption curve of the material.

[0025] Figure 9 This is a schematic diagram illustrating the working principle of the H-type electrolytic cell for synergistic uranium extraction and organic matter degradation according to the present invention.

[0026] Figure 10 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 The material at a potential of -1.3V vs. Ag / AgCl, for 100 mg·L⁻¹ -1 Uranyl ions with different concentrations of diethylene glycol dimethyl ether (10~200 g·L⁻¹) -1 Kinetic diagram of electrochemical extraction of uranium from a mixed solution of ( ).

[0027] Figure 11 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 The material at different potentials (vs. Ag / AgCl) at 100 mg·L -1 Uranyl and 100 g·L -1 Electrochemical kinetics of uranium extraction from a diethylene glycol-dimethyl ether mixture.

[0028] Figure 12 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5The material was tested at different pH values ​​and at potentials of -1.3V vs. Ag / AgCl for 1 hour at a concentration of 100 mg·L⁻¹. -1 Uranyl and 100 g·L -1 Graph showing the effect of electrochemical uranium extraction in a diethylene glycol-dimethyl ether mixed solution.

[0029] Figure 13 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 The material, at a potential of -1.3V vs. Ag / AgCl, reacted with 1 g·L⁻¹ of Ag / AgCl within 1 hour. -1 Different sulfates (except calcium sulfate in saturated solution), 100 mg·L -1 Uranyl and 100 g·L -1 The effect of electrochemical extraction of uranium from a diethylene glycol-dimethyl ether mixture is shown in the figure.

[0030] Figure 14 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 The material at a potential of -1.3V vs. Ag / AgCl showed a yield of 1 g·L⁻¹ over 1 hour. -1 Different sodium salts, 100 mg·L -1 Uranyl and 100 g·L -1 The effect of electrochemical extraction of uranium from a diethylene glycol-dimethyl ether mixture is shown in the figure.

[0031] Figure 15 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 The material at a potential of -1.3V vs. Ag / AgCl, for 100 mg·L⁻¹ -1 Uranyl and 10 g·L -1 A diagram illustrating the cyclic effect of electrochemical extraction of uranium from a mixed solution of different organic pollutants.

[0032] Figure 16 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 The material at a potential of -1.3V vs. Ag / AgCl, for 100 mg·L⁻¹ -1 Uranyl and 100 g·L -1 Circulation effect diagram of electrochemical extraction of uranium from a diethylene glycol-dimethyl ether mixed solution.

[0033] Figure 17 The Cu2(TTB) is prepared according to Example 1 of the present invention. 0.5 The graph shows the evolution of the ratio of degradation intermediates to the initial diethylene glycol dimethyl ether concentration over time in an H-type electrolytic cell. Detailed Implementation

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. The embodiments described are only preferred embodiments of the present invention and are not intended to limit the present invention in any way.

[0036] This invention provides a copper-based metal-organic framework material with the chemical formula Cu2(TTB). 0.5 TTB is the organic ligand 1,2,4,5-tetra(1H-tetrazazole-5-yl)phenyl ion. Cu2(TTB) 0.5 It belongs to the monoclinic crystal system, space group C2 / c, and exhibits a pore-free, close-packed three-dimensional structure. The cell parameters are: a = 16.1176(11) Å, b = 8.8433(5) Å, c = 9.9041(6) Å, α = γ = 90°. o , β=98.854(2) o V=1394.84(15)Å 3 It should be understood that these unit cell parameters are for Cu2(TTB) prepared in the examples. 0.5 The typical characterization value is given, and the scope of protection of this invention includes Cu2(TTB) with the same structure whose cell parameters fluctuate slightly within the test error range. 0.5 Material.

[0037] This invention also provides a method for preparing a copper-based metal-organic framework material, comprising placing 1,2,4,5-tetra(1H-tetrazazole-5-yl)benzene (H4TTB) and CuCN in an organic solvent containing an alkaline compound and an additive, and heating to 150-170°C for 2-4 days to obtain the copper-based metal-organic framework material. In a preferred embodiment, the molar ratio of H4TTB to CuCN is 1:3.5 to 1:4.5. In another preferred embodiment, the molar ratio of H4TTB to CuCN is 1:4. In a preferred embodiment, the alkaline compound is ammonia. In a preferred embodiment, the additive is ammonium fluoride. In a preferred embodiment, the organic solvent is N,N-dimethylformamide and ethanol. In a preferred embodiment, the volume ratio of N,N-dimethylformamide to ethanol is 0.8-1:1-1.2. In another preferred embodiment, the volume ratio of N,N-dimethylformamide to ethanol is 1:1. In a preferred embodiment, the volume ratio of N,N-dimethylformamide to ammonia is 1~1.4:1~2.0. In another preferred embodiment, the volume ratio of N,N-dimethylformamide to ammonia is 1:1.75. In a preferred embodiment, the solvothermal reaction is carried out in a high-pressure reactor. In a preferred embodiment, the temperature is increased to 150~170°C at a heating rate of 9~11°C / min for isothermal reaction. In another preferred embodiment, the heating rate is 10°C / min. In another preferred embodiment, the reaction time is 3 days.

[0038] The present invention also provides the application of the above-mentioned copper-based metal-organic framework material in the preparation of electrode catalysts for the electrochemical extraction of uranium from aqueous solutions.

[0039] This invention also provides a system for the electrochemical extraction of uranium and the co-degradation of organic matter, which is an H-type electrolytic cell, comprising a cathode chamber and an anode chamber separated by an ion exchange membrane. The cathode chamber contains a cathode, and the anode chamber contains an anode. The cathode comprises the aforementioned copper-based metal-organic framework material. The ion exchange membrane is an anion exchange membrane. In a preferred embodiment, the cathode is made by loading the aforementioned copper-based metal-organic framework material onto a conductive substrate. In a preferred embodiment, the copper-based metal-organic framework material is loaded using a binder. In a preferred embodiment, the conductive substrate is carbon paper, carbon cloth, or graphite felt. In a preferred embodiment, the binder is an ionic binder. In a preferred embodiment, the binder is Nafion 117. In a preferred embodiment, the anode is a platinum sheet. In a preferred embodiment, the H-type electrolytic cell further includes an external power source for applying a reduction potential to the cathode.

[0040] This invention also provides a method for electrochemically extracting uranium and co-degrading organic matter using the above-described system, comprising the following steps: S1, adding wastewater containing uranyl ions and organic pollutants to the cathode and anode chambers; S2, adding an electrolyte to the wastewater for electrocatalytic reaction; S3, applying a potential of -1.3V to -1.9V relative to the reference electrode to the cathode for constant potential electrolysis; wherein, during electrolysis, the uranyl ions are reduced to insoluble precipitates on the cathode surface, while the organic pollutants are degraded in the anode region. In a preferred embodiment, the Ag / AgCl electrode is the reference electrode. In a preferred embodiment, the electrolyte is 0.5M sodium sulfate. In a preferred embodiment, the organic pollutant is one or more selected from diethylene glycol dimethyl ether, 1-fluoro-1,1-dichloroethane, 1,1-dichloroethane, and dichloromethane. In a preferred embodiment, the concentration of diethylene glycol dimethyl ether in the wastewater is 0-100 g·L⁻¹. -1 In a preferred embodiment, the pH value of the wastewater to be treated is 1.0 to 8.0. In a preferred embodiment, the concentration of uranyl ions in the wastewater to be treated is 0 to 100 mg / L. -1 In a preferred embodiment, the wastewater to be treated also contains substances selected from Na. + Ca 2+ Co 2+ Ni 2+ Al 3+ Fe 3+ F − Cl − ,Br − I − NO3 − and CO3 2− One or more coexisting ions.

[0041] The equipment and test parameters used for material characterization and performance testing in the embodiments of this invention are as follows:

[0042] X-ray powder diffraction characterization test: X-ray powder diffraction data collection was completed on a Bruker D8 Advance diffractometer with an operating voltage of 40 kV and a current of 40 mA. The test was completed by continuous scanning in the range of 3° to 40° using graphite monochromated copper target X-rays (CuKα, λ=1.54178 Å).

[0043] X-ray single-crystal diffraction characterization and structural analysis: Single crystals of appropriate size were selected under a microscope, and data were collected using Mo-Kα (λ=0.71073Å) radiation at 100K on a Bruker D8 VENTURE CMOS photon 100 diffractometer with helios mxmultilayer single-crystal diffractometer. All crystal data were corrected for Lp factor and empirical absorption correction. Absorption correction was performed using the SADABS program, and the structure was analyzed using the direct method. Anisotropic corrections were then performed on all non-hydrogen atoms in the framework using the full matrix least squares method. The coordinates of hydrogen atoms on all carbon atoms were obtained by theoretical hydrogen addition, followed by isotropic corrections for the hydrogen atoms.

[0044] Simulation and conversion of X-ray powder diffraction patterns of single-crystal structures: completed using Mercury software;

[0045] Infrared spectroscopy (IR) testing: A Thermo Nicolet 6700 FTIR spectrometer equipped with a diamond attenuated total reflectance (ATR) accessory was used, with a testing range of 400-4000 cm⁻¹. -1 ;

[0046] Thermogravimetric analysis (TGA): The test was conducted using a NETZSCH STA 449 F3 in a nitrogen atmosphere at a heating rate of 10 °C / min, with a test temperature range of 40 °C to 800 °C.

[0047] Nitrogen adsorption test: The N2 adsorption isotherm at 77K was tested using a Bestar adsorption instrument;

[0048] Electrochemical performance testing: The tests were conducted at room temperature using a CHI-660D electrochemical workstation and a standard three-electrode system.

[0049] Example 1: Dense copper-based metal-organic framework material Cu2(TTB) 0.5 Preparation

[0050] Weigh H4TTB (17.5 mg, 0.05 mmol) and CuCN (17.9 mg, 0.2 mmol) at a molar ratio of 1:4, and add ammonium fluoride (18.5 mg, 0.5 mmol). Dissolve all three in 2 mL of N,N-dimethylformamide (DMF), sonicate to homogenize the mixture, add 2 mL of ethanol and 3.5 mL of ammonia to the solution, and sonicate again to obtain a homogeneous mixture.

[0051] The above mixture was transferred to a 25 mL high-pressure reactor and heated at 10 °C / min. -1The temperature was increased to 160℃ at a rising rate, and the reaction was carried out at a constant temperature of 160℃ for 3 days in a solvothermal manner. After the reaction was completed, the reaction vessel was naturally cooled to room temperature, and then filtered to separate the crystals and filtrate.

[0052] The obtained crystals were washed and purified by washing with DMF three times and then with acetonitrile three times. After washing, the crystals were dried to obtain a dense copper-based metal-organic framework material Cu2(TTB). 0.5 .

[0053] The prepared Cu2(TTB) 0.5 Optical microscopy and X-ray single-crystal diffraction characterization were performed. Optical micrographs showed that the single crystal exhibited a yellow blocky structure, with dimensions of approximately 0.2 mm × 0.18 mm × 0.07 mm. The crystal quality and size met the requirements for indoor X-ray single-crystal diffraction instrumentation. Some parameters of its crystallographic diffraction point data collection and structural refinement are shown in Table 1.

[0054] Table 1 Cu2(TTB) 0.5 Single crystal parameters

[0055]

[0056] The crystal structure analysis results are as follows: Cu2(TTB) 0.5 It belongs to the monoclinic crystal system, space group C2 / c, and its asymmetric unit contains half a TTB. 4- Ligands and two crystallographically independent Cu + .like Figure 1 As shown, Cu1 coordinates with nitrogen atoms on four different tetrazolium groups, forming a tetrahedral coordination configuration; Cu2 coordinates with nitrogen atoms on three tetrazolium groups, exhibiting a trigonal planar coordination configuration. Figure 2 As shown, adjacent Cu + Bridging via tri- or tetra-coordinated tetrazolium groups, the Cu···Cu spacing is 3.4586(2)~3.5729(2) Å, per TTB 4- Two nitrogen atoms on the ligand remain uncoordinated, and each TTB 4- The ligand can connect to 12 Cu + This leads to the formation of a three-dimensional close-packed crystal structure without pores, such as... Figure 3 and Figure 4 As shown, the material has no internal pore channels, meaning its porosity is 0.

[0057] In such Figure 5 The X-ray powder diffraction pattern obtained from the single-crystal data simulation shown is consistent with that of Cu2(TTB). 0.5 In the actual measured PXRD spectrum, the diffraction peak positions and intensities of the two lines are highly consistent, indicating that the synthesized Cu2(TTB) 0.5The crystal structure is completely consistent with the structure obtained from single-crystal analysis.

[0058] Take equal amounts of Cu2(TTB) 0.5 Single-crystal materials were soaked in aqueous solutions of different pH values ​​for 24 hours, and an equal amount of Cu2(TTB) was taken. 0.5 Single-crystal materials were irradiated with β and γ rays, and then subjected to PXRD analysis to study Cu2(TTB). 0.5 Its chemical stability and radiation resistance. Figure 6 It includes simulated spectral lines, spectral lines immersed in aqueous solution at pH=0, spectral lines immersed in aqueous solution at pH=14, 200 kGy β-irradiation spectral lines, and 200 kGy γ-irradiation spectral lines, with irradiation doses of 2 × 10⁻⁶. 4 Gy·h -1 and 1.2×10 3 Gy·h -1 The positions of all diffraction peaks are attributed to the initial Cu2(TTB). 0.5 The crystal form and the lack of significant change in the intensity of the characteristic diffraction peaks indicate that Cu2(TTB) is intact. 0.5 The crystal form remained unchanged in strong acid and strong alkali aqueous solutions and under 200 kGy dose of β and γ ray irradiation, exhibiting excellent chemical stability and radiation resistance.

[0059] For Cu2(TTB) 0.5 Thermogravimetric analysis of the material, such as Figure 7 As shown, the remaining mass does not decrease significantly below 400℃, indicating that the material has good thermal stability below 400℃.

[0060] For Cu2(TTB) 0.5 Materials for nitrogen adsorption, such as Figure 8 As shown, the material exhibits almost no adsorption of nitrogen, further demonstrating that it possesses a dense, non-porous, three-dimensional close-packed structure. Figure 3 , Figure 4 The characterization results are consistent.

[0061] Example 2: Synergistic Degradation of Electrocatalytic Uranyl Reduction and Diethylene Glycol Dimethyl Ether

[0062] Take 5 mg of Cu2(TTB) prepared in Example 1. 0.5 The material was dispersed in a mixture of 30 μL of 5 wt% Nafion 117 solution and 1000 μL of ethanol, and ultrasonically treated for 0.5 h to obtain a uniform catalyst ink. This catalyst ink was then loaded into an air-pumped spray gun and uniformly sprayed onto a 2 × 2 cm area. 2 The working electrode is prepared by drying the microporous hydrophilic side of gas diffusion carbon paper under an irradiation lamp, and Cu2(TTB) is applied to this electrode. 0.5 The final catalyst loading was 1.25 mg·cm³.-2 .

[0063] The prepared supported Cu2(TTB) 0.5 A standard three-electrode system was constructed using gas diffusion carbon paper as the working electrode (cathode), a platinum sheet as the counter electrode (anode), and an Ag / AgCl electrode as the reference electrode. This three-electrode system was placed in an H-type electrolytic cell, with the cathode and anode chambers separated by an anion exchange membrane to form independent cathode and anode reaction zones. A mixed treatment solution was added to both the cathode and anode chambers of the electrolytic cell. This mixed treatment solution consisted of a mixture of wastewater to be treated and electrolyte. The wastewater contained uranyl ions and diethylene glycol dimethyl ether organic pollutants. The uranyl ions existed as uranyl nitrate at a concentration of 100 mg·L⁻¹. -1 The electrolyte is 0.5M sodium sulfate.

[0064] like Figure 9 As shown, the synergistic working principle of this H-type electrolytic cell is as follows: the external power supply provides a reduction potential to the system, driving electrons to flow from the anode to the cathode; in the cathode chamber, uranyl ions (UO2)... 2+ On the catalyst surface, it is electrocatalytically reduced to unstable UO2 with a +5 oxidation state. + Subsequently, a rapid disproportionation reaction occurs, forming a water-insoluble sodium diuranate compound precipitate with the participation of hydroxide and sodium ions, which is deposited on the electrode, thus achieving uranium extraction. In the anode chamber, diethylene glycol dimethyl ether is oxidized and degraded into smaller molecule products; simultaneously, OH- produced by the electrolysis of water at the cathode... - The uranium migrates to the anode chamber through the anion exchange membrane, maintaining the charge balance of the system and ensuring the efficient and coordinated extraction and degradation of organic matter.

[0065] A constant reduction potential is applied to the cathode, ranging from -1.3V to -1.9V, and constant potential electrolysis is performed at room temperature to achieve the reduction and deposition of uranyl ions in the cathode chamber and the degradation of diethylene glycol dimethyl ether in the anode chamber.

[0066] At a potential of -1.3V vs. Ag / AgCl, for a substance containing 100 mg·L⁻¹ -1 Uranyl nitrate and different concentrations of diethylene glycol dimethyl ether (10~200 g·L⁻¹) -1 Electrochemical extraction of uranium is performed using a mixed solution of , such as Figure 10 As shown, the curves correspond to 10 g·L -1 50g·L -1 100g·L -1 200g·L -1 The diethylene glycol dimethyl ether concentration system showed that: 10 g·L -1 In the system, the residual rate of uranyl ions dropped sharply to near zero within 20 minutes, indicating an extremely rapid reduction rate; 50 g·L -1100g·L -1 In the system, the initial reduction rate decreased slightly, but the residual uranyl ion concentration still dropped to approximately 0 within 60 minutes; 200 g·L⁻¹ -1 In this system, due to limited mass transfer, the reduction kinetics of uranyl ions are slowed down, with a reduction efficiency of only about 20% within 80 minutes. The above experimental results indicate that increasing the concentration of diethylene glycol dimethyl ether (DGE) slightly inhibits the initial reduction rate of uranyl ions; at a potential of -1.3 V vs. Ag / AgCl, a DGE concentration ≤ 100 g·L⁻¹ is optimal. -1 At that time, Cu2(TTB) 0.5 It can still maintain efficient uranyl ion reduction performance.

[0067] At different potentials, for substances containing 100 mg·L -1 Uranyl and 100 g·L -1 Electrochemical extraction of uranium using a mixed solution of diethylene glycol and dimethyl ether, such as... Figure 11 As shown, the curves correspond to potentials of -1.1V, -1.2V, -1.3V, -1.5V, and -1.9V, respectively. The results show that as the cathode potential gradually shifts negative, the uranium ion extraction efficiency significantly improves, and the reaction kinetic rate accelerates; when the potential is ≤-1.3V, the uranium extraction efficiency exceeds 98.2% within 60 minutes. The above experimental results indicate that the suitable potential range for efficient uranium extraction in this system is -1.3V to -1.9V.

[0068] At different pH values ​​and potentials of -1.3V vs. Ag / AgCl, the effect of 100 mg·L⁻¹ on Ag / AgCl concentration over 1 hour was investigated. -1 Uranyl and 100 g·L -1 Electrochemical extraction of uranium using a mixed solution of diethylene glycol and dimethyl ether, such as... Figure 12 As shown, under strongly acidic conditions (pH=1.0), the uranium extraction efficiency can still reach approximately 85.3%; the extraction performance gradually improves with increasing pH, reaching 97.2% at pH=5.0; and within the pH range of 4-8, the uranium extraction efficiency remains above 94.9%. These experimental results demonstrate that this electrocatalytic system exhibits excellent uranium extraction adaptability across a wide pH range from acidic to near-neutral.

[0069] At a potential of -1.3V vs. Ag / AgCl, the concentration of 1 g·L⁻¹ Ag / AgCl was measured within 1 hour. -1 Different sulfates (calcium sulfate with a concentration of less than 1 g·L) -1 (excluding saturated solutions), 100 mg·L -1 Uranyl and 100 g·L -1 Electrochemical extraction of uranium using a mixed solution of diethylene glycol and dimethyl ether, such as... Figure 13 As shown, in Na + Co 2+Ni 2+ Al 3+ Fe 3+ In the coexistence system, uranium extraction efficiency remained above 93.8%; (The text abruptly ends here, likely due to an incomplete sentence or missing information.) 2+ In this system, the uranium extraction efficiency reached 90.0%. The above experimental results demonstrate that this system has good resistance to interference from common cations.

[0070] At a potential of -1.3V vs. Ag / AgCl, the concentration of 1 g·L⁻¹ Ag / AgCl was measured within 1 hour. -1 Different sodium salts, 100 mg·L -1 Uranyl and 100 g·L -1 Electrochemical extraction of uranium using a mixed solution of diethylene glycol and dimethyl ether, such as... Figure 14 As shown, in Cl − ,Br − I − NO3 − In coexisting systems, uranium extraction efficiency exceeds 91.4%; even in F, which has strong complexing properties... − CO3 2− Under coexistence conditions, the uranium extraction efficiency can be maintained above 85.6%. These experimental results demonstrate that the system also exhibits excellent resistance to interference from common anions.

[0071] At a potential of -1.3V vs. Ag / AgCl, for a substance containing 100 mg·L⁻¹ -1 Uranyl and 10 g·L -1 Electrochemical extraction of uranium was performed using a mixed solution of different organic pollutants (1-fluoro-1,1-dichloroethane, 1,1-dichloroethane, dichloromethane, and diethylene glycol dimethyl ether). Figure 15 As shown, the uranium extraction efficiency exceeded 91.0% within 60 minutes in various organic pollutant coexistence systems. These experimental results indicate that the system exhibits good tolerance to a variety of organic pollutants and is not only applicable to the diethylene glycol dimethyl ether system.

[0072] At a potential of -1.3V vs. Ag / AgCl, for a substance containing 100 mg·L⁻¹ -1 Uranyl and 100 g·L -1 Electrochemical extraction of uranium using a mixed solution of diethylene glycol and dimethyl ether, such as... Figure 16 As shown, after ten consecutive extraction cycles, Cu2(TTB) 0.5 The uranium extraction efficiency remained above 96.4%, the catalytic activity did not show significant decline, and the total uranium extracted reached 195 g·g⁻¹. -1 The above experimental results demonstrate that this material exhibits excellent cyclic stability and can be repeatedly used for uranium extraction, making it a highly promising adsorption-electrocatalyst.

[0073] At a potential of -1.3V vs. Ag / AgCl, for a substance containing 100 mg·L⁻¹ -1 Uranyl and 10 g·L -1 Electrochemical extraction of uranium was performed using a mixed solution of diethylene glycol and dimethyl ether. Figure 17 The graph shows the evolution of the ratio of degradation intermediates to the initial concentration of diethylene glycol dimethyl ether (DME) over time in an H-type electrolytic cell. The curves correspond to DME and its intermediates (ethylene glycol monomethyl ether (EGME), methoxyacetic acid (MAA), ethylene glycol (EG), ethanol (EtOH), glycolic acid (GA), methanol (MeOH), and formic acid (HCOOH)). The results show that DME is consumed rapidly, and its characteristic signal almost disappears after 6 hours of reaction. The degradation products are diverse, indicating the existence of diverse DME degradation pathways in the system. The content of each degradation intermediate changes significantly over time; after 24 hours of reaction, only formic acid remains as a degradation product, achieving deep degradation of DME.

[0074] The above performance test results show that the Cu2(TTB) prepared by this invention... 0.5 The material exhibits excellent chemical stability, thermal stability, radiation resistance, and recyclability. When used as a cathode catalyst, it forms an H-type electrocatalytic cell system that can efficiently and rapidly extract uranyl ions in complex systems with a wide pH range, multiple coexisting ions, and high concentrations of diethylene glycol dimethyl ether. Simultaneously, it can deeply degrade diethylene glycol dimethyl ether, achieving synergistic effects of uranium extraction and organic pollutant degradation.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A copper-based metal-organic framework material, characterized in that, The chemical formula is Cu2(TTB). 0.5 It belongs to the monoclinic crystal system, with space group C2 / c, and exhibits a three-dimensional structure with no pores and close packing.

2. The copper-based metal-organic framework material according to claim 1, characterized in that, Cu2(TTB) 0.5 The unit cell parameters are: a = 16.1176(11) Å, b = 8.8433(5) Å, c = 9.9041(6) Å, α = γ = 90 o , β=98.854(2) o V=1394.84(15)Å 3 .

3. The method for preparing the copper-based metal-organic framework material according to claim 1 or 2, characterized in that, The process involves placing H4TTB and a copper source in an organic solvent containing alkaline compounds and additives, heating it to 150-170°C for a solvothermal reaction for 2-4 days to obtain a copper-based metal-organic framework material.

4. The preparation method according to claim 3, characterized in that, The copper source is CuCN, the alkaline compound is ammonia, the additive is ammonium fluoride, and the organic solvent is N,N-dimethylformamide and ethanol.

5. The preparation method according to claim 4, characterized in that, The molar ratio of H4TTB to CuCN is 1:3.5 to 1:4.5, the volume ratio of N,N-dimethylformamide to ethanol is 0.8 to 1:1 to 1.2, and the volume ratio of N,N-dimethylformamide to ammonia is 1 to 1.4:1 to 2.

0.

6. The application of the copper-based metal-organic framework material according to claim 1 or 2 in the preparation of electrode catalysts for the electrochemical extraction of uranium from aqueous solutions.

7. A system for electrochemically extracting uranium and synergistically degrading organic matter, characterized in that, The system is an H-type electrolytic cell, comprising a cathode chamber and an anode chamber separated by an ion exchange membrane. The cathode chamber contains a cathode, and the anode chamber contains an anode. The cathode comprises a copper-based metal-organic framework material according to claim 1 or 2.

8. The system according to claim 7, characterized in that, The ion exchange membrane is an anion exchange membrane, the cathode is made by loading the copper-based metal-organic framework material onto a conductive substrate, and the anode is a platinum sheet.

9. A method for electrochemically extracting uranium and co-degrading organic matter using the system as described in claim 7 or 8, characterized in that, Includes the following steps: S1, add wastewater containing uranyl ions and organic pollutants to the cathode chamber and anode chamber; S2, add electrolyte to the wastewater for electrocatalytic reaction; S3, apply a potential of -1.3V to -1.9V relative to the reference electrode to the cathode for constant potential electrolysis; wherein, during electrolysis, the uranyl ions are reduced to insoluble deposits on the cathode surface, while the organic pollutants are degraded in the anode region.

10. The method according to claim 9, characterized in that, The Ag / AgCl electrode serves as the reference electrode, and the electrolyte is sodium sulfate. The organic pollutant is one or more selected from diethylene glycol dimethyl ether, 1-fluoro-1,1-dichloroethane, 1,1-dichloroethane, and dichloromethane. The concentration of diethylene glycol dimethyl ether in the wastewater to be treated is 0~100 g·L⁻¹. -1 The pH value of the wastewater to be treated is 1.0~8.0, and the concentration of uranyl ions in the wastewater to be treated is 0~100 mg·L⁻¹. -1 .

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