A method of constructing a physical field enhanced electrochemical uranium deposition

Abstract

This invention discloses a method for constructing a physical field-enhanced electrochemical uranium deposition system, comprising: constructing an electrolytic cell: employing a bottom-in, top-out electrolytic cell with dimensions of 70 mm × 70 mm × 45 mm, the solution inlet located at the bottom left, and the outlet located at the bottom right, 20-43 mm from the bottom; and circulating the solution via a peristaltic pump connected to an external hose, using Co3O4@FeO x -IF is the cathode, NiO x -NF is the anode; a physical field coupling reaction is constructed: fluoride- and uranium-containing wastewater is added to the electrolytic cell, and the reaction is carried out under the conditions of a constructed physical field; the physical field is one of parallel coupling of a flow field and an electric field, or parallel coupling of a flow field and an electric field with an external magnetic field. This invention achieves effective product deposition, and a high removal rate can be achieved for fluoride- and uranium-containing wastewater systems when constructing a physical field, proving the feasibility and superiority of constructing a physical field.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment and resource recycling technology. More specifically, this invention relates to a method for constructing a physical field to enhance electrochemical uranium deposition. Background Technology

[0002] Nuclear energy, as a highly efficient, low-carbon, and clean energy source, plays an increasingly important role in the global energy structure transformation and the response to climate change. The proportion of nuclear power generation continues to rise, and uranium, as a key element in the nuclear fuel cycle, is directly related to the sustainable development of the nuclear energy industry. However, throughout the entire nuclear fuel cycle—including uranium mining, nuclear fuel processing, reactor operation, and spent fuel reprocessing—a large amount of uranium-containing radioactive wastewater is inevitably generated. If this fluorine- and uranium-containing wastewater is discharged into the environment without effective treatment, it not only causes the loss of valuable uranium resources but also poses a long-term threat to ecosystems and human health due to its radioactivity and chemical toxicity.

[0003] The most common type of uranium-containing wastewater is fluoride-containing uranium-containing wastewater. This is because fluoride ions and uranyl ions (UO2) react to form fluoride ions. 2 + There are strong coordination interactions between them, forming a variety of stable uranyl fluoride complexes (UO2F) in solution. + UO2F2, UO2F3 - UO2F4 2- The enrichment and separation of uranium, including nuclear wastewater, greatly increases the difficulty of uranium separation. Therefore, developing efficient and reliable methods for uranium enrichment and separation to extract uranium from these nuclear wastewaters is crucial for the sustainable development of nuclear energy and the secondary recycling of uranium resources.

[0004] Electrochemical methods, with their unique separation mechanism, have demonstrated significant advantages in the treatment of fluoride- and uranium-containing wastewater. Under the influence of an applied electric field, positively charged uranyl ions are driven by the electric field force to migrate directionally to the cathode surface and undergo a reduction reaction, while strongly coordinating anions in the system (such as F⁻, CO₃²⁻)... 2- The ions (such as uranyl ions) migrate towards the anode, effectively reducing the interference of competing ions on uranium adsorption and reduction. Currently, research in this field mainly focuses on the design and modification of electrode materials. Researchers are committed to improving the catalytic activity and selectivity of electrodes through various strategies, such as: constructing abundant active sites on the surface of metal oxides using defect engineering; introducing oxygen vacancies to adjust the electronic structure of the material and enhance the adsorption and activation of uranyl ions; and optimizing charge transfer pathways and the binding energy of reaction intermediates through heterostructure construction and single-atom doping. These material innovations have significantly improved the uranium extraction performance from fluorine- and uranium-containing wastewater.

[0005] However, the research and optimization of process parameters is a critical shortcoming that urgently needs to be addressed in moving electrochemical uranium extraction technology from the laboratory to practical engineering applications. Currently, research on process parameters lacks both a systematic investigation of the coupling effects of multiple parameters and verification and optimization in fluorine-containing uranium wastewater systems. Optimizing process parameters is not only fundamental to achieving "high-efficiency, low-energy" operation but also a prerequisite for ensuring reaction selectivity, product stability, and long-term operational reliability of the equipment. Therefore, while continuously innovating electrode materials, it is imperative to conduct in-depth research on electrochemical uranium extraction processes to promote the practical application of this technology. Summary of the Invention

[0006] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0007] To achieve these objectives and other advantages of the present invention, a method for constructing a physical field-enhanced electrochemical uranium deposition system is provided, comprising the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 20-43 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing a physical field coupled reaction: Add fluoride- and uranium-containing wastewater to the electrolytic cell and carry out the reaction under the conditions of constructing a physical field; The physical field is one of the following: parallel coupling of flow field and electric field, or parallel coupling of flow field and electric field with an external magnetic field.

[0008] Preferably, in step one, Co3O4@FeO x The preparation method of -IF includes the following steps: S1. Immerse 1cm×2cm pieces of foamed iron in 0.2 mol / L hydrochloric acid and sonicate for 5-20 minutes to clean the surface. Remove and then immerse in anhydrous ethanol for ultrasonic cleaning 1-5 times, each time for 5-20 minutes. After vacuum drying at 50-70℃ for 8-16 hours, place in a tube furnace and calcine at 400-500℃ in an air stream at a rate of 3-7℃ / min for 2-6 hours to obtain reddish-brown foamed iron FeO. x -IF; S2, FeO x-IF was immersed in 10-20 mL of a mixed solution containing 0.8-1 g of 2-methylimidazole and 0.5-1 g of cobalt nitrate hexahydrate at room temperature for 12-48 h, and then calcined in a tube furnace at a rate of 3-7 °C / min to 350-450 °C for 1-3 h to obtain a black integrated electrode material Co3O4@FeO. x -IF.

[0009] Preferably, in step S1, FeO is used. x -IF is modified, and the modification method is as follows: A. FeO x -IF was added to 20-100 mL of 1,3-propanediol, followed by 1-2 mL of 3-aminopropyltriethoxysilane. The mixture was reacted at 70-90 °C with stirring at 300-600 rpm for 10-18 h. After the reaction, the mixture was filtered, washed 1-3 times each with deionized water and anhydrous ethanol, and then dried under vacuum at 70-80 °C for 4-8 h to obtain pretreated FeO. x -IF; B. Add 2-10 mg of reduced graphene oxide and 100-500 μL of 1 wt% Nafion solution to 20-100 mL of anhydrous ethanol, sonicate for 10-30 min, and then place in pretreated FeO. x -IF, ultrasonic treatment for 1-3 h, then vacuum drying at 40-50℃ for 6-10 h to obtain modified FeO. x -IF.

[0010] Preferably, in step one, NiO x The preparation method of -NF is as follows: cut nickel foam into 1cm×2cm pieces, soak them in acetone for 12-24h, then ultrasonically clean them with anhydrous ethanol 1-5 times, each ultrasonic cleaning time being 5-20min. After vacuum drying at 50-70℃ for 8-16h, place them in a tube furnace and heat them to 350-450℃ in an air flow at a rate of 3-7℃ / min, calcining for 1-3h to obtain NiO. x -NF.

[0011] Preferably, in step two, the volume of the fluoride- and uranium-containing wastewater is 100-220 mL.

[0012] Preferably, in step two, the uranium concentration in the fluorine-containing and uranium-containing wastewater is 10~800 mg / L, and the fluoride ion concentration is 1~50 g / L.

[0013] Preferably, in step two, the flow velocity in the physical field is 5~15 mL / min.

[0014] Preferably, in step two, the electric field in the physical field is in constant current mode of a DC power supply.

[0015] Preferably, in step two, the current density of the electric field in the physical field is 20~40 mA / cm². 2 .

[0016] Preferably, in step two, the strength of the magnetic field in the physical field is 10~40mT.

[0017] Preferably, in step two, the magnetic field is constructed by arranging permanent magnets outside the electrolytic cell to create an external magnetic field.

[0018] The present invention has at least the following beneficial effects: (1) The flow-electric field coupling mode in the physical field of this invention has a decisive influence on the deposition performance. By comparing the three coupling modes of parallel, perpendicular, and reverse, the flow-electric field coupling mode was determined to be the optimal mode. In this mode, the flow field direction is perpendicular to UO2. 2 + With consistent electromigration directions, a synergistic directional driving force was formed, resulting in a uranium deposition efficiency of 95.91% after 6 hours of reaction, significantly higher than that of vertical coupling (80.69%) and reverse coupling (68.14%). Finite element simulations further revealed that the electrode placement corresponding to parallel coupling was most conducive to uniform streamline distribution and enhanced mass transfer, verifying its rationality as the optimal coupling method from a fluid dynamics perspective.

[0019] (2) The external magnetic field in the physical field of this invention can significantly regulate the particle size of the deposited products and improve the reaction efficiency. Laser particle size analysis shows that the magnetic field will affect the characteristic particle size (D) of the particles on the upper liquid surface. 50 The nanometer size was drastically reduced from hundreds of nanometers (528.2~1001.5 nm) in the absence of a magnetic field to the nanometer scale (4.9~9.1 nm), achieving effective product deposition. Under a 30 mT magnetic field, a high removal rate was achieved in a short time for fluoride- and uranium-containing wastewater systems, demonstrating the feasibility and superiority of magnetic field-assisted deposition. Through the directional coupling of the flow field and electric field and the microscopic control of the magnetic field, efficient uranium deposition in fluoride- and uranium-containing wastewater was achieved, providing a theoretical basis and technical pathway for multi-physics field synergistic enhancement of electrochemical uranium extraction.

[0020] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0021] Figure 1 The diagram shows the three current-electric coupling methods (current-horizontal, current-perpendicular, and current-reverse) of Embodiment 1 and Comparative Examples 1-2 of the present invention, along with the pH test point locations. Figure 2 The figures show the performance of three current coupling methods in Embodiment 1 and Comparative Examples 1-2 of the present invention. Figure 3 This is a diagram showing the local residual uranium content of three current coupling methods in Embodiment 1 and Comparative Examples 1-2 of the present invention; Figure 4 The pH values ​​of (a) Example 1 under horizontal current; (b) Comparative Example 1 under vertical current; and (c) Comparative Example 2 under reverse current. Figure 5 (a) Finite element simulation model of the present invention; (b) Surface pressure of the finite element simulation model; Figure 6 The following are three views of the present invention: (a) a 3D view (side view) of the internal streamline distribution of the electrolytic cell; (b) a 3D view (top view) of the internal streamline distribution of the electrolytic cell; (c) a 3D cross-sectional view of the internal streamline of the electrolytic cell; and (d) a 2D view of the internal streamline distribution of the electrolytic cell. Figure 7 For the present invention (a) K in the electrolytic cell + Distribution; (b) UO2 in the electrolytic cell 2+ Distribution; (c) OH in the electrolytic cell - distributed; Figure 8 For the present invention (a) H in the electrolytic cell + Distribution; (b) F in the electrolytic cell - distributed; Figure 9 This is a simulation diagram of uranium species distribution in fluorine- and uranium-containing wastewater under different pH conditions according to the present invention; Figure 10 This is a schematic diagram of the electrochemical uranium extraction reactor with an external magnetic field according to the present invention; Figure 11 This is a diagram illustrating the mechanism of the external magnetic field applied in this invention. Figure 12 The figures show the electrochemical uranium deposition performance and experimental results of Examples 2 and 5 of this invention. Figure 13 Examples 2 and 5 of the present invention are: (a) the time gradient of particle size at the liquid surface without a magnetic field; (b) the time gradient of particle size at the bottom without a magnetic field; (c) the time gradient of particle size at the liquid surface with an applied magnetic field; and (d) the time gradient of particle size at the bottom with an applied magnetic field. Figure 14 This is a multimodal size distribution diagram of the upper liquid surface and bottom in Example 2 without a magnetic field; Figure 15 This is a multimodal size distribution diagram of the upper liquid surface and bottom of the liquid under an applied magnetic field in Example 5; Figure 16 This is a test diagram of the applied magnetic field strength using the teslameter of this invention; Figure 17 The electrochemical uranium deposition performance diagrams are for Examples 3 and 6-7. Figure 18The pH values ​​inside a 150 mL reactor without a magnetic field in Example 3 of the present invention are: (a) pH values ​​inside a 150 mL reactor with an external magnetic field strength of 20 mT in Example 6; and (c) pH values ​​inside a 150 mL reactor with an external magnetic field strength of 30 mT in Example 7. Figure 19 These are electrochemical uranium deposition performance diagrams for Examples 4 and 8-9 of the present invention; Figure 20 These are electrochemical uranium deposition performance diagrams for Examples 9-11 of the present invention; Figure 21 The pH values ​​inside a 200 mL reactor without a magnetic field in Example 4 of the present invention are: (a) pH values ​​inside a 200 mL reactor with an external magnetic field strength of 20 mT in Example 8; and (c) pH values ​​inside a 200 mL reactor with an external magnetic field strength of 30 mT in Example 9. Figure 22 The power consumption diagrams for three current coupling methods in Embodiment 1 and Comparative Examples 1-2 of the present invention are shown. Figure 23 The power consumption diagrams for a 100mL volume of the present invention with and without a magnetic field are shown in Examples 2 and 5 of the present invention. Figure 24 The power consumption diagrams for a volume of 150 mL with and without a magnetic field in Examples 3 and 6-7 of the present invention are shown. Figure 25 This is a power consumption diagram for different magnetic field strengths in a volume of 200 mL in Examples 4 and 8-9 of the present invention. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0023] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0024] In this invention, Co3O4@FeO x The preparation method of -IF includes the following steps: S1. The 1cm × 2cm pieces of foamed iron were immersed in 0.2 mol / L hydrochloric acid and ultrasonically cleaned for 10 minutes. After removal, they were immersed in anhydrous ethanol and ultrasonically cleaned three times, each time for 10 minutes. After vacuum drying at 60℃ for 12 hours, they were placed in a tube furnace and calcined at 450℃ for 3 hours in an air stream at a rate of 5℃ / min to obtain reddish-brown foamed iron FeO. x -IF; S2, FeO x-IF was immersed in 10 mL of a mixed solution containing 0.8211 g of 2-methylimidazole and 0.5806 g of cobalt nitrate hexahydrate for 24 h at room temperature, and then calcined in a tube furnace at a rate of 5 °C / min to 400 °C for 2 h to obtain a black integrated electrode material Co3O4@FeO. x -IF.

[0025] In this invention, because air-calcined foamed iron produces two valence states, +2 and +3, the material obtained in this invention is named in the form of 'x'. Spectroscopic characterization confirms its phase composition as Fe2O3. To ensure consistency in material naming, the material name in this invention is uniformly designated as FeO. x .

[0026] In this invention, NiO x The preparation method of -NF is as follows: Nickel foam is cut into 1cm × 2cm pieces, soaked in acetone for 24 hours, then ultrasonically cleaned three times with anhydrous ethanol for 10 minutes each time. After vacuum drying at 60℃ for 12 hours, it is placed in a tube furnace and heated to 400℃ at a rate of 5℃ / min in an air stream, and calcined for 2 hours to obtain NiO. x -NF.

[0027] In this invention, because air-calcined nickel foam produces two valence states, +2 and +3, the materials obtained in this invention are named in the form of 'x'. To ensure consistency in material naming, the material name in this invention is uniformly NiO. x .

[0028] Example 1 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 42 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO. x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 220 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), the reaction proceeds. 2 The reaction takes place under parallel coupling conditions.

[0029] Example 2 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 20 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 100 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), a physical field coupling reaction is established. 2 The reaction takes place under parallel coupling conditions.

[0030] Example 3 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 30 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 150 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), a physical field coupling reaction is established. 2 The reaction takes place under parallel coupling.

[0031] Example 4 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 40 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO. x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 200 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), a physical field coupling reaction is established. 2The reaction takes place under parallel coupling.

[0032] Example 5 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 20 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 100 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), a physical field coupling reaction is established. 2 The reaction is carried out under parallel coupling with an external magnetic field strength of 20mT.

[0033] Example 6 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 30 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 150 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), a physical field coupling reaction is established. 2 The reaction is carried out under parallel coupling with an external magnetic field strength of 20mT.

[0034] Example 7 This embodiment is basically the same as embodiment 6, except that the external magnetic field with an intensity of 20mT in step two is replaced with an external magnetic field with an intensity of 30mT.

[0035] Example 8 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 40 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO. x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 200 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), a physical field coupling reaction is established. 2 The reaction is carried out under parallel coupling with an external magnetic field strength of 20mT.

[0036] Example 9 This embodiment is basically the same as embodiment 8, except that the external magnetic field with an intensity of 20mT in step two is replaced with an external magnetic field with an intensity of 30mT.

[0037] Example 10 This embodiment is basically the same as Embodiment 9, except that the Co3O4@FeO in step one is changed. x -IF is replaced with Co3O4@A / rGO-FeO x -IF;Co3O4@A / rGO-FeO x The preparation method of -IF includes the following steps: S1. The 1cm × 2cm pieces of foamed iron were immersed in 0.2 mol / L hydrochloric acid and ultrasonically cleaned for 10 minutes. After removal, they were immersed in anhydrous ethanol and ultrasonically cleaned three times, each time for 10 minutes. After vacuum drying at 60℃ for 12 hours, they were placed in a tube furnace and calcined at 450℃ for 3 hours in an air stream at a rate of 5℃ / min to obtain reddish-brown foamed iron FeO. x -IF, will FeO x -IF is modified, and the modification method is as follows: A. FeO x -IF was added to 30 mL of 1,3-propanediol, followed by 1.5 mL of 3-aminopropyltriethoxysilane. The mixture was reacted at 80 °C with stirring at 400 rpm for 14 h. After the reaction was complete, the mixture was filtered, washed twice each with deionized water and anhydrous ethanol, and dried under vacuum at 80 °C for 5 h to obtain pretreated FeO. x -IF; B. Add 3 mg of reduced graphene oxide and 200 μL of 1 wt% Nafion solution to 30 mL of anhydrous ethanol, sonicate for 20 min, and then place in pretreated FeO.x -IF, ultrasonic treatment for 1 h, then vacuum drying at 50℃ for 8 h, to obtain modified FeO x -IF; S2, Modified FeO x -IF was immersed in 10 mL of a mixed solution containing 0.8211 g of 2-methylimidazole and 0.5806 g of cobalt nitrate hexahydrate for 24 h at room temperature, and then calcined in a tube furnace at a rate of 5 °C / min to 400 °C for 2 h to obtain a black integrated electrode material, denoted as Co3O4@A / rGO-FeO. x -IF.

[0038] Example 11 This embodiment is basically the same as Embodiment 9, except that the Co3O4@FeO in step one is changed. x -IF should be replaced with Co3O4@A-FeO x -IF;Co3O4@A-FeO x The preparation method of -IF includes the following steps: S1. The 1cm × 2cm pieces of foamed iron were immersed in 0.2 mol / L hydrochloric acid and ultrasonically cleaned for 10 minutes. After removal, they were immersed in anhydrous ethanol and ultrasonically cleaned three times, each time for 10 minutes. After vacuum drying at 60℃ for 12 hours, they were placed in a tube furnace and calcined at 450℃ for 3 hours in an air stream at a rate of 5℃ / min to obtain reddish-brown foamed iron FeO. x -IF, will FeO x -IF is modified, and the modification method is: FeO x -IF was added to 30 mL of 1,3-propanediol, and 1.5 mL of 3-aminopropyltriethoxysilane was added. The mixture was reacted at 80 °C and 400 r / min with stirring for 14 h. After the reaction was completed, the mixture was filtered, washed twice with deionized water and twice with anhydrous ethanol, and dried under vacuum at 80 °C for 5 h to obtain modified FeO. x -IF; S2, Modified FeO x -IF was immersed in 10 mL of a mixed solution containing 0.8211 g of 2-methylimidazole and 0.5806 g of cobalt nitrate hexahydrate for 24 h at room temperature, and then calcined in a tube furnace at a rate of 5 °C / min to 400 °C for 2 h to obtain a black integrated electrode material, denoted as Co3O4@A-FeO. x -IF.

[0039] Comparative Example 1 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 42 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO. x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 220 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), the reaction proceeds. 2 The reaction takes place under vertical coupling conditions.

[0040] Comparative Example 2 A method for constructing a physical field-enhanced electrochemical uranium deposition system includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 42 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO. x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing the physical field coupling reaction: Add 220 mL of fluoride- and uranium-containing wastewater (uranium concentration of 500 mg / L and fluoride ion concentration of 30 g / L) to the electrolytic cell. Under the influence of a flow field (flow rate of 10 mL / min) and an electric field (DC power supply in constant current mode, current density of 30 mA / cm²), the reaction proceeds. 2 The reaction takes place under reverse coupling conditions.

[0041] Figure 1 This document presents three coupling modes (parallel, perpendicular, and reverse) for flow-electric coupling in Example 1 and Comparative Examples 1-2 of this invention, along with pH test point diagrams. From the perspective of synergistic regulation of the flow field and electric field, its influence on electrochemical uranium deposition behavior is systematically investigated. In this invention, the direction of uranyl ion movement is defined as the electric field direction, and the spatial relationship between the flow field and electric field under each coupling mode is illustrated. Schematic diagrams of the three coupling modes and pH test point locations are shown below. Figure 1 As shown.

[0042] Figure 2 The figures show the performance of three current-electric coupling methods in Embodiment 1 and Comparative Examples 1-2 of the present invention. The present invention systematically compared the uranium deposition performance under three coupling methods—parallel coupling, perpendicular coupling, and reverse coupling—and the results are as follows. Figure 2As shown, under the parallel coupling of the flow field and electric field in Example 1, the uranium removal efficiency reached 95.91% after only 6 hours of reaction, significantly higher than that of the vertical coupling in Comparative Example 1 (80.69%) and the reverse coupling in Comparative Example 2 (68.14%) during the same period. After 8 hours of reaction, the efficiency of parallel coupling slowly increased to 96.77%. The performance curves clearly show that parallel coupling exhibits an extremely high uranium removal rate in the first 4 hours of reaction. This phenomenon can be attributed to the flow field and electric field providing forces in the same direction, resulting in a superposition effect between the electric field-driven directional migration and the flow field-driven fluid migration, jointly promoting UO2 removal. 2+ The uranium moves towards the working electrode region, enhancing the mass transfer process and allowing it to fully participate in the reaction. The performance curve flattens out after 4 hours of reaction, which is due to the significant decrease in the residual uranium concentration in the solution after the highly efficient electrochemical reaction in the early stage.

[0043] Under conditions of perpendicular coupling between the flow field and the electric field, this mode exhibits a performance curve that is initially rapid but then slows down. This phenomenon stems from the fact that in this mode, the cathode surface is parallel to the flow field direction, and the solution flows along the electrode surface, effectively thinning the diffusion boundary layer and facilitating the transport of uranyl ions from the solution to the electrode interface. However, due to the flow field direction being parallel to UO2... 2+ The electric fields were perpendicular to each other, failing to form a continuous directional driving force, which caused the mass transfer enhancement effect to gradually weaken as the reaction progressed, reaching only 90% removal rate by 8 hours.

[0044] Under reverse coupling of the flow field and electric field, the overall uranium deposition performance was poor, with a removal rate of only 68.14% after 6 hours of reaction, significantly lower than the other two modes. The direct cause of this phenomenon is the misalignment of the flow field direction with the UO2 content. 2+ The electric field migration direction is opposite, and the force generated by the solution flow cancels out the directional migration force driven by the electric field, severely hindering the effective migration of uranyl ions to the cathode region. Furthermore, the performance curves show an increasing efficiency trend in the later stages of the reaction, reaching approximately 75% by 8 hours. This is due to the OH- produced by the hydrogen evolution reaction (HER) at the cathode. - Driven by the flow field, it diffuses inside the electrolytic cell and reacts with UO2 in the solution. 2+ A reaction occurs, thereby achieving the indirect removal of uranium.

[0045] Figure 3 The figures show the local residual uranium content of three flow-electric coupling methods in Example 1 and Comparative Examples 1-2 of this invention. To reveal the spatial regulation effect of the flow-electric coupling method on the electrochemical uranium deposition process, the local residual uranium concentration in the reactor inlet, outlet, and middle region was measured under a constant flow rate of 10 mL / min. The results are shown below. Figure 3As shown in the figure, comparative analysis of local uranium concentrations allows for a deeper understanding of the mechanism of electrochemical uranium deposition reactions within the reactor under different coupling modes. Experimental results show that, at a flow rate of 10 mL / min, the residual uranium concentrations at various points within the reactor exhibit similar uniformity under all three coupling modes. However, significant differences in residual uranium concentrations exist at different points under different coupling modes.

[0046] The residual uranium concentration at all spatial points in parallel coupling was significantly lower than that in vertical coupling and reverse coupling. The residual uranium concentration at the reactor inlet, outlet, and middle region remained at a low level with no significant difference between regions, indicating that horizontal coupling has a positive effect on the overall electrochemical uranium deposition. The residual uranium concentration at each point in vertical coupling was slightly higher than that in parallel coupling. This is because although the flow field force promotes the movement of target ions, it lacks a driving force coordinated with the electric field direction, and the overall electrochemical reaction has not reached equilibrium, resulting in relatively less uniform local uranium concentration. The residual uranium concentration at each point in reverse coupling was the highest among the three, essentially because the flow field force hinders the movement of target ions towards the cathode.

[0047] Figure 4 The pH values ​​are shown in (a) Example 1 with horizontal current flow; (b) Comparative Example 1 with vertical current flow; and (c) Comparative Example 2 with reverse current flow. In this invention, the pH values ​​of the time gradient at various points within the reactor were measured under three coupling modes, and the results are as follows: Figure 4 As shown. Under parallel coupling conditions ( Figure 4 a) The pH values ​​at the cathode and at P3 and P4 show an increasing trend with reaction time, with the most significant increase rate occurring in the first 3 hours of the reaction. This phenomenon is due to the fact that horizontal coupling promotes the electrochemical reaction, resulting in the generation of a large amount of OH- in the cathode region. - This leads to a rapid increase in local pH. The pH in the anolyte region shows a relatively gradual upward trend, while the pH generated in the cathode region... - Under the influence of the flow field, it is continuously diffused to the anode, thus significantly improving the overall uranium removal efficiency. Under vertical coupling conditions ( Figure 4 (b) The pH distribution within the reactor exhibits a significant spatial symmetry. The pH values ​​at the cathode and at points P2 and P3 remain at a high level (pH≈10), because the vigorous electrochemical reactions in the cathode region continuously produce OH-. - The pH values ​​at the anode and P1 and P4 also showed a significant upward trend. This phenomenon indicates that, under vertical coupling conditions, the OH- produced at the cathode... - It will migrate towards the anode region under the influence of the flow field. Under reverse coupling conditions ( Figure 4 c) The pH values ​​at each point showed an overall rapid upward trend. Although the pH value near the cathode (located on the left) remained relatively high due to electrochemical reactions, the flow field direction was opposite to that of UO2.2+ The electric fields are in opposite directions, resulting in the generation of OH-. - Under the influence of the flow field, it continues to migrate to the right-side anode region, causing the pH value on the anode side to increase. Simultaneously, UO2... 2+ Driven by the electric field, the material migrates towards the cathode, but is hindered by the flow field, resulting in a significant reduction in overall deposition efficiency.

[0048] Figure 5 (a) Finite element simulation model of the present invention; (b) Surface pressure of the finite element simulation model. Based on the determination that parallel coupling of the flow field and electric field is the optimal coupling mode, this invention employs finite element simulation to simulate the streamline distribution of ions inside the reactor under parallel coupling conditions in order to explore the promoting mechanism of this mode on the electrochemical uranium deposition process within the reactor. In constructing the physical model, all factors inside the actual reactor were fully considered, and the solid structure of the electrode clamping device and the electrode material itself were included in the model scope to ensure the geometric realism of the simulation. The established finite element model is as follows: Figure 5 As shown in a. Figure 5 b shows a pressure distribution cloud map inside the electrolyzer. It is clearly observed from the figure that areas of higher pressure are mainly concentrated at the inlet, outlet, and near the electrode surfaces. The pressure at the inlet and outlet primarily stems from the momentum changes generated when fluid flows in and out driven by an external peristaltic pump. The pressure on the electrode surface is due to two factors: firstly, the electrode material itself has a macroscopic porous structure, creating flow resistance as the solution flows through its complex internal channels; secondly, during the continuous electrochemical reaction, the hydrogen and oxygen evolution reactions generate microbubbles on the electrode surface and within the pores, and the movement of these bubbles exerts pressure on the electrode surface.

[0049] Figure 6 The following are three views of the streamline distribution inside the electrolytic cell: (a) a side view; (b) a top view; (c) a 3D cross-sectional view; and (d) a 2D view. In the finite element simulation, the overall solution streamlines are first analyzed, and each streamline is shown below. Figure 6 As shown. Figure 6 a and Figure 6 b. From the 3D and 2D side views of the streamline inside the electrolytic cell, it can be clearly observed that the bottom left is the inlet and the top right is the outlet. There is a main streamline between the inlet and outlet, and there is a backflow phenomenon at the right electrode. This phenomenon can effectively promote the participation of uranyl ions in the solution in the electrochemical reaction. Therefore, the position of the working electrode is more suitable for the right electrode, which verifies that the anode is on the left and the cathode is on the right in the parallel coupling of the flow field and the electric field.

[0050] Figure 7 For the present invention (a) K in the electrolytic cell + Distribution; (b) UO2 in the electrolytic cell2+ Distribution; (c) OH in the electrolytic cell - Distribution. It can be clearly observed that the streamlines of the three ions are basically the same, indicating that mass transfer in the reactor is mainly caused by fluid flow. For K... + The observation that the pressure is lower at the anode surface and higher at the cathode surface fully demonstrates that K + The fluid flows and fully participates in the reaction to generate the target product K2U2O7. Hydrogen evolution occurs at the right cathode, producing OH-. - According to the electroneutrality condition, the cathode region requires positively charged species to neutralize the excess negative charge; therefore, the Kc in the cathode region... + and UO2 2+ Concentration increased. It is worth noting that, in Figure 7 In step b, the pressure on the surface of the cathode material is very small, which is consistent with the results of uranium deposition in this invention.

[0051] Figure 8 For the present invention (a) H in the electrolytic cell + Distribution; (b) F in the electrolytic cell - Distribution. H + and F - These are the other two ions in the high-fluoride, fluoride-containing, and uranium-containing wastewater of this invention, and their concentration distribution cloud map and streamline distribution diagram are shown in Figure 8. H + The formation of H is due to the oxygen evolution reaction at the anode. + It then migrates towards the electrolytic cell outlet under the influence of the flow field, and some H exists there. + With OH - Neutralization results in water. Electrochemical treatment of high-fluoride uranium-containing wastewater effectively breaks the strong coordination complex between fluoride ions and uranyl ions, reducing F... - It accumulates at the anode under the influence of electric and flow fields.

[0052] Figure 9 This is a simulation diagram of uranium species distribution in fluorine-containing uranium wastewater under different pH conditions according to the present invention. In the aforementioned study, the overall pH value of the simulated nuclear wastewater solution was consistently high during the electrochemical reaction process. Visual MINTEQ 3.1 software was used to simulate the distribution of uranium species in uranium solutions (500 mg / LU and 30 g / LF) at different pH conditions. - Distribution of uranium species in ). The results are as follows Figure 9 In uranium-containing wastewater with high fluoride content, when pH > 5, the main uranium species in the solution is UO2F4. 2- .

[0053] Figure 10 This is a schematic diagram of the electrochemical uranium extraction reactor with an external magnetic field according to the present invention. To achieve uranium deposition assisted by an external magnetic field, the present invention arranges permanent magnets outside the electrolytic cell to construct an external magnetic field, as shown in the specific arrangement below. Figure 10As shown.

[0054] Figure 11 This is a diagram illustrating the mechanism of the external magnetic field in this invention. The external magnetic field must fully consider UO2F4. 2- The charged property of the object, so that it is subjected to an effective Lorentz force, such as Figure 11 As shown. The permanent magnets on both sides have polarities of S pole at the top and N pole at the bottom, with the magnetic field direction from the N pole to the S pole, forming an external magnetic field. Inside the electrolytic cell, UO2F4 2- The direction of motion of the positive charge is influenced by both the electric field and the flow field, and both directions are consistent, moving from left to right. According to the left-hand rule, the direction of motion of the positive charge, the direction of the magnetic field, and the direction of the force satisfy a vector relationship. For the negatively charged UO2F4 2- The magnetic field points from N to S, and the ion moves to the right. It can be deduced that the Lorentz force acting on it is vertically downwards. This downward Lorentz force can cause UO₂F₄ to... 2- The movement generates a deflection towards the bottom of the reactor, which is expected to improve uranium deposition efficiency.

[0055] Figure 12 The figures show the electrochemical uranium deposition performance and experimental results of Examples 2 and 5 of this invention. To investigate the enhancing effect of an external magnetic field on the electrochemical uranium deposition process, this invention selected 100 mL (solution height ≈ 2 cm) of high-fluoride uranium-containing wastewater as the research object, and systematically examined the uranium deposition performance under conditions of no magnetic field and an external magnetic field. The results are as follows: Figure 12 As shown in the figure. Experimental results indicate that the electrochemical performance under an applied magnetic field is significantly better than that under no magnetic field conditions. Under an applied magnetic field, the removal efficiency reaches 94.57% after 2 hours of reaction. Furthermore, after the reaction, it can be clearly observed that the uranium deposition products are stably enriched at the bottom of the electrolytic cell, and there are no visible suspended particles on the upper surface of the solution, indicating that the magnetic field assistance not only improves the uranium removal rate but also promotes the effective deposition of the products.

[0056] Figure 13 Examples 2 and 5 of this invention show: (a) the time gradient of particle size at the liquid surface without a magnetic field; (b) the time gradient of particle size at the bottom without a magnetic field; (c) the time gradient of particle size at the liquid surface with an applied magnetic field; and (d) the time gradient of particle size at the bottom with an applied magnetic field. To verify the effect of uranium deposition assisted by an applied magnetic field, this invention uses laser particle size analysis to determine the particle size at the upper and lower layers of the solution under a time gradient. Figure 13 The results shown are the logarithmic size distribution of the particle size.

[0057] Figure 14 This is a multimodal size distribution diagram of the upper liquid surface and bottom without a magnetic field in Example 2.

[0058] Figure 15This is a multimodal size distribution diagram of the upper liquid surface and bottom of the liquid under an applied magnetic field in Example 5.

[0059] Figure 14 and Figure 15 The multimodal size distribution diagrams for Examples 2 and 5 are shown with and without a magnetic field and with an applied magnetic field, respectively. The particle size data of the upper layer of the two solutions are compared in Tables 1 to 4. In the particle size analysis, D... 10 D 50 D 90 These are three key statistical indicators, among which D 50 Also known as median particle size, it refers to the particle size value corresponding to a cumulative particle size distribution percentage of 50%. It is the most critical indicator for describing a sample.

[0060] Table 1. Data on particle size in the upper layer of solution without a magnetic field. 1h-Upper 274.9 528.2 1014.6 2h-Upper 290.4 495.7 846.0 3h-Upper 511.7 1001.5 1959.9 Table 2. Data on particle size at the bottom of the solution in the absence of a magnetic field. 1h-Bottom 377.0 637.6 1078.4 2h- Bottom 881.9 1874.3 3983.5 3h- Bottom 1294.6 2257.6 3937.3 Table 3. Size data of particles in the upper layer of solution under an applied magnetic field. 1h-Upper-M 2.2 4.9 10.9 2h-Upper-M 3.0 6.3 13.1 3h-Upper-M 4.3 9.1 19.2 Table 4. Size data of particles at the bottom of the solution under an applied magnetic field. 1h-Bottom -M 421.8 668.0 1058.0 2h- Bottom -M 774.4 1626.3 3415.1 3h- Bottom -M 787.9 1667.8 3530.0 In a magnetic field-free environment, by Figure 14 As shown in Table 1, the upper layer of the solution, D 50 The particle size data from 1 h to 3 h were 528.2 nm, 495.7 nm, and 1001.5 nm, respectively. The D at the bottom of the solution... 50 The data shows a trend of increasing with reaction time (from 637.6 nm to 2257.6 nm), indicating that uranium deposition occurs during the electrochemical reaction process. In the middle stage of the reaction, the floating products on the upper layer of the solution precipitate downwards due to aggregation. In the later stage of the reaction, due to the efficient electrochemical reaction, larger particles also exist on the upper layer of the solution. At the bottom of the solution, the particles consistently show an increasing trend due to deposition.

[0061] In an applied magnetic field, as shown in Tables 3 and 4, for the upper layer of the solution, D 50Data shows that the particle size is significantly smaller than that without a magnetic field, and the particle size distribution is extremely narrow, exhibiting a stable symmetrical single-peak distribution. This phenomenon indicates that the applied magnetic field can effectively assist uranium deposition downwards. At the bottom of the solution, the particle size value shows no significant change in the later stages of the reaction. This is because the efficient electrochemical reaction and the uranium deposition assisted by the applied magnetic field ensure that the deposited product remains stable at the bottom. These particle size distribution characteristics confirm, at the microscopic level, the assisting effect of the applied magnetic field on electrochemical uranium deposition. The Lorentz force applied by the applied magnetic field not only enhances ion mass transfer but also promotes effective product deposition, providing strong experimental evidence for the technical parameters of magnetic field-assisted electrochemical uranium extraction processes.

[0062] Figure 16 This is a test diagram of the applied magnetic field strength measured by the teslameter of this invention. This invention further investigates the influence of solution volume (liquid level) and applied magnetic field strength on the electrochemical uranium deposition process. To determine the magnetic field strength constructed by the applied magnetic field, the magnetic field strength placed between two permanent magnets was measured using a teslameter. Figure 16 As shown, when one permanent magnet is placed on each side of the reactor, the measured peak magnetic field strength is approximately 23.29 mT. By stacking permanent magnets at this location to enhance the magnetic field, i.e., placing two magnets on each side, the measured peak magnetic field strength significantly increases to approximately 40 mT, indicating that stacking magnets can effectively increase the magnetic field strength. To evaluate the magnetic field strength inside the reactor under actual operating conditions, the electrolytic cell was further placed between the permanent magnets for measurement. The tests showed that the actual measured peak value with one magnet on each side was 21.49 mT, and the actual measured peak value with two magnets on each side was 32.91 mT. Under the condition of placing the same number of magnets, the thickness of the electrolytic cell attenuates the magnetic field, resulting in a slightly lower measured value by the teslameter than the value without the electrolytic cell. Considering the actual reaction environment, to ensure the accuracy of subsequent magnetic field strength parameters, the magnetic field strength with one permanent magnet on each side of the reactor was marked as 20 mT, and the magnetic field strength with two permanent magnets on each side was marked as 30 mT.

[0063] Figure 17 The figures show the electrochemical uranium deposition performance of Examples 3 and 6-7. Based on verifying that the applied magnetic field promotes electrochemical uranium deposition, this invention further increased the solution height to 3 cm (solution volume ≈ 150 mL) and, while keeping other experimental conditions constant, systematically investigated the effect of different magnetic field strengths on uranium deposition performance. The results are as follows: Figure 17As shown in the figure, the experimental results indicate that the uranium removal efficiency in the electrolytic cell increases with the increase of the magnetic field strength. Under no magnetic field conditions, it takes at least 6 hours to reach the 90% standard (the removal rate after 6 hours is only 92.91%). When the magnetic field strength is 20 mT, the removal rate reaches 92.23% after 4 hours of reaction. Further increasing the magnetic field strength to 30 mT, the removal rate is 91.11% after 2 hours of reaction, and as the reaction continues, the removal rate further increases to 97.23% after 6 hours. These data clearly demonstrate that an external magnetic field can significantly accelerate uranium deposition, and the effect increases with increasing magnetic field strength.

[0064] Figure 18 The pH values ​​are shown in (a) Example 3 (without magnetic field), (b) Example 6 (with an applied magnetic field of 20 mT), and (c) Example 7 (with an applied magnetic field of 30 mT). This invention simultaneously measured the pH changes over time at four characteristic points (inlet, outlet, cathode, and anode) within the electrolytic cell under different magnetic field strengths. Figure 18 It can be observed that the pH data distribution is relatively concentrated under the condition of no magnetic field, with the pH value at the cathode and outlet around 10, and the pH value at the anode and inlet around 8.

[0065] In contrast, the pH distribution under an applied magnetic field exhibits significant differences. The pH values ​​in the inlet and anode regions are significantly lower than those in the outlet and cathode regions. This is primarily due to the Lorentz force's directional migration of charged particles. Under an applied magnetic field, all charged particles in the solution are affected by the Lorentz force. For negatively charged OH-... - and UO2F4 2- The Lorentz force acting on it is in the same direction (downward according to the left-hand rule). The downward Lorentz force causes it to deflect towards the working electrode region during horizontal movement, promoting the oxidation of OH. - and UO2F4 2- The enrichment and reaction at the cathode accelerate the electrochemical reaction. For positively charged K... + and H + In terms of the direction of the Lorentz force it experiences, it is upward, but due to K + The concentration in the solution is high, and H + Its main function is to maintain the electroneutrality of the solution rather than directly participate in the reaction. Under the applied magnetic field, the pH change trends at the four sites generally tended to be gradual, indicating that magnetic field assistance not only enhances the reaction of the target ion UO2F4... 2- The mass transfer process also promotes the uniform distribution and dynamic equilibrium of the chemical environment within the electrolyzer, enabling the reaction to proceed continuously and efficiently in a relatively stable environment.

[0066] Figure 19 The figures show the electrochemical uranium deposition performance of Examples 4 and 8-9 of this invention. Based on the aforementioned research, the liquid level was further increased to 4 cm (solution volume ≈ 200 mL), and the experimental results showed that ( Figure 19 Increasing the liquid level did not alter the promoting effect of the applied magnetic field on electrochemical uranium deposition, but the overall deposition efficiency decreased compared to a liquid level of 3 cm (150 mL). This is because the solution volume increases; when the liquid level increases from 3 cm to 4 cm, the solution volume increases by 50 mL, leading to a larger total amount of uranium to be processed by the working electrode, thus prolonging the required time. Under a magnetic field strength of 20 mT, the uranium removal rate reached 92.83% after 6 hours of reaction. When the magnetic field strength was increased to 30 mT, the removal rate reached 95.20% after 3 hours. As the reaction time progressed, the increase in removal rate leveled off, reaching only 95.51% after 6 hours, with a relatively small overall change. This indicates that increasing the reaction solution significantly promotes electrochemical uranium deposition with increased magnetic field strength. A magnetic field strength of 30 mT not only shortens the time required to achieve efficient removal but also achieves a higher removal efficiency.

[0067] Figure 20 These are electrochemical uranium deposition performance diagrams from Examples 9-11 of this invention. Experimental results show that Co3O4@FeO... x -FeO in IF x After modification, Co3O4@A / rGO-FeO was obtained. x -IF with Co3O4@A-FeO x When -IF was used as the electrode cathode, the uranium removal rate increased compared to the uranium removal rate after 6 hours. This may be due to Co3O4@A / rGO-FeO x -FeO in IF x -IF, after being aminated and loaded with reduced graphene oxide, increases its specific surface area and functional groups, thereby enhancing interfacial bonding, increasing active sites, and improving its uranium removal capacity. Meanwhile, Co3O4@A-FeO... x -IF only applies to FeO x - IF hydroxylation treatment is more effective than Co3O4@FeO in removing uranium. x -IF, but compared to Co3O4@A / rGO-FeO x -IF removal effectiveness is reduced.

[0068] Figure 21The pH values ​​are as follows: (a) pH inside a 200 mL reactor without a magnetic field in Example 4 of this invention; (b) pH inside a 200 mL reactor with an applied magnetic field strength of 20 mT in Example 8; and (c) pH inside a 200 mL reactor with an applied magnetic field strength of 30 mT in Example 9. The pH values ​​at various points under these conditions were also measured, and the results are as follows: Figure 21 As shown in the figure, the pH data at each point is relatively concentrated under no magnetic field conditions, and all points show an increasing trend with the reaction progress. Under the condition of an applied magnetic field, the pH distribution shows an evolutionary characteristic closely related to the magnetic field strength. When the magnetic field strength is 20 mT, the pH values ​​at the inlet and anode areas also show high values. Under this magnetic field strength, the magnetic field's effect on the directional control of charged particles inside the electrolyzer is not obvious. Combined with the performance data of 20 mT, it takes 6 hours to achieve a 90% removal efficiency, indicating that in a large solution system, the magnetic field strength (20 mT) constructed by two permanent magnets on both sides is insufficient to support uranium deposition. When the magnetic field strength is 30 mT, the pH value at the inlet is similar to that at the anode, and the pH value at the outlet is similar to that at the cathode, and the overall pH change at each point tends to be gradual. This indicates that the enhanced magnetic field can effectively drive the directional movement of charged particles, making OH... - With UO2F4 2- The reactor exhibits efficient enrichment and complexation precipitation near the cathode, resulting in a more uniform and stable chemical environment.

[0069] Experimental results combining different liquid level heights and magnetic field strengths reveal a regularity. For smaller solutions (e.g., 150 mL), increasing the magnetic field strength has a relatively limited effect on overall performance improvement; however, for larger solutions (e.g., 200 mL), increasing the magnetic field strength significantly promotes the electrochemical reaction. This phenomenon can be attributed to the matching relationship between the range of magnetic field regulation of charged particle motion and the solution volume. In large-volume systems, a stronger magnetic field can effectively cover a wider spatial area, allowing more UO2F4 particles far from the electrode to move. 2- The material is deflected towards the cathode by the Lorentz force, thereby significantly improving the overall removal efficiency.

[0070] In this invention, energy consumption calculations were performed for the electrostatic coupling method and the external magnetic field-assisted uranium deposition.

[0071] Figure 22 The diagram shows the power consumption of three current-electric coupling methods in Embodiment 1 and Comparative Examples 1-2 of this invention. From the perspective of current-electric coupling methods, the energy consumption of the three coupling relationships shows slight differences. The energy consumption of parallel, vertical, and reverse coupling are 1.18, 1.25, and 1.26 kW·h, respectively. Among them, parallel coupling has the lowest energy consumption, which is closely related to its high mass transfer efficiency and uniform pH distribution.

[0072] Figure 23 This is a power consumption diagram for a volume of 100 mL with or without a magnetic field in Examples 2 and 5 of the present invention. Figure 24 This is a power consumption diagram for a volume of 150 mL with or without a magnetic field in Examples 3 and 6-7 of the present invention. Figure 25 This is a power consumption diagram for different magnetic field strengths in a volume of 200 mL in Examples 4 and 8-9 of the present invention. Figure 23-25 The energy consumption is related to the applied magnetic field strength, where the magnetic field (MF) is abbreviated as MF. In the experiment verifying magnetic field-assisted uranium deposition, with a solution level of 2 cm (volume 100 mL), the energy consumption with and without a magnetic field was 0.74 kW·h and 0.77 kW·h, respectively, showing no significant difference. This indicates that the applied magnetic field did not result in unnecessary energy loss; rather, by optimizing reaction kinetics, a slight reduction in energy consumption was achieved. Figure 23-24 The energy consumption is calculated as follows: at a liquid level of 3 cm (150 mL), the energy consumption is 1.14 kW·h for no magnetic field (MF), 1.15 kW·h for a magnetic field strength of 20 mT, and 1.13 kW·h for a magnetic field strength of 30 mT. At a liquid level of 4 cm (200 mL), the energy consumption is 1.11 kW·h for no magnetic field (MF), 1.09 kW·h for a magnetic field strength of 20 mT, and 1.14 kW·h for a magnetic field strength of 30 mT. Analysis of the energy consumption data shows that the applied magnetic field has no significant impact on the overall energy consumption. The applied magnetic field only plays a guiding role in the migration of charged particles in the solution, accelerating the electrochemical reaction. In summary, parallel coupling exhibits the best energy consumption performance, while the applied magnetic field effectively improves the reaction efficiency without significantly increasing energy consumption. These results provide important design basis for designing low-energy-consumption, high-efficiency electrochemical uranium extraction processes.

[0073] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for constructing a physical field-enhanced electrochemical uranium deposition system, characterized in that, Includes the following steps: Step 1: Construction of the electrolytic cell: A bottom-in, top-out electrolytic cell is adopted, with cell dimensions of 70 mm × 70 mm × 45 mm. The solution inlet is located at the bottom left, and the outlet is located at the bottom right, 20-43 mm from the bottom. Solution circulation is achieved through a peristaltic pump connected to an external hose, using Co3O4@FeO x -IF is the cathode, NiO x -NF is the anode; Step 2: Constructing a physical field coupled reaction: Add fluoride- and uranium-containing wastewater to the electrolytic cell and carry out the reaction under the conditions of constructing a physical field; The physical field is one of the following: parallel coupling of flow field and electric field, or parallel coupling of flow field and electric field with an external magnetic field.

2. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 1, characterized in that, In step one, Co3O4@FeO x The preparation method of -IF includes the following steps: S1. Immerse 1cm×2cm pieces of foamed iron in 0.2 mol / L hydrochloric acid and sonicate for 5-20 minutes to clean the surface. Remove and then immerse in anhydrous ethanol for ultrasonic cleaning 1-5 times, each time for 5-20 minutes. After vacuum drying at 50-70℃ for 8-16 hours, place in a tube furnace and calcine at 400-500℃ in an air stream at a rate of 3-7℃ / min for 2-6 hours to obtain reddish-brown foamed iron FeO. x -IF; S2, FeO x -IF was immersed in 10-20 mL of a mixed solution containing 0.8-1 g of 2-methylimidazole and 0.5-1 g of cobalt nitrate hexahydrate at room temperature for 12-48 h, and then calcined in a tube furnace at a rate of 3-7 °C / min to 350-450 °C for 1-3 h to obtain a black integrated electrode material Co3O4@FeO. x -IF.

3. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 1, characterized in that, In step one, NiO x The preparation method of -NF is as follows: cut nickel foam into 1cm×2cm pieces, soak them in acetone for 12-24h, then ultrasonically clean them with anhydrous ethanol 1-5 times, each ultrasonic cleaning time being 5-20 min. After vacuum drying at 50-70℃ for 8-16h, place them in a tube furnace and heat them to 350-450℃ in an air flow at a rate of 3-7℃ / min, calcining for 1-3h to obtain NiO. x -NF.

4. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 1, characterized in that, In step two, the volume of the fluorine- and uranium-containing wastewater is 100-220 mL.

5. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 1, characterized in that, In step two, the uranium concentration in the fluorine-containing and uranium-containing wastewater is 10~800 mg / L, and the fluoride ion concentration is 1~50 g / L.

6. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 1, characterized in that, In step two, the flow velocity in the physical field is 5~15 mL / min.

7. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 1, characterized in that, In step two, the electric field in the physical field is in constant current mode of DC power supply.

8. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 1, characterized in that, In step two, the current density of the electric field in the physical field is 20~40 mA / cm². 2 .

9. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 1, characterized in that, In step two, the strength of the magnetic field in the physical field is 10~40mT.

10. The method for constructing a physical field-enhanced electrochemical uranium deposition as described in claim 9, characterized in that, In step two, the magnetic field is constructed by arranging permanent magnets outside the electrolytic cell to create an external magnetic field.

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