Fiber material for enriching uranium as well as preparation method and application of fiber material

Abstract

The invention discloses a fiber material for enriching uranium as well as a preparation method and application thereof, the fiber material for enriching uranium adopts a fiber surface microstructure regulation and control technology, polyamidoxime is grafted on the surface of the fiber material, and nano-particles with broad-spectrum antibacterial performance are modified in situ to prepare a novel uranium extraction fiber brush with biological adhesion resistance. The fiber material is used for enriching uranium, so that the purpose of efficiently extracting uranium from seawater and salt lakes is achieved. The nano-particles are used for blocking or weakening the hydrogen-bond interaction between high-density amidoxime, so that the growth phenomenon caused by too high grafting degree of a traditional polyamidoxime material is effectively inhibited, and the effective utilization rate of a specific ligand is improved, thereby improving the uranium extraction capacity. Meanwhile, the biological adhesion resistance of the fiber material is improved by utilizing the broad-spectrum bactericidal performance of the nanoparticles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of uranium enrichment, and particularly relates to a fiber material for uranium enrichment, a preparation method and application thereof. BACKGROUND

[0002] As a strategic resource of the country, uranium is also the "food" for the development of nuclear energy of the country, and the rapid development of nuclear energy will inevitably lead to a substantial increase in the demand for uranium raw materials. The uranium concentration in Dazece Salt Lake can reach 324 ug / L, and the uranium concentration in Qinghai Lake is 18.3 ug / L. Therefore, from the long-term development, it is an inevitable choice to enrich uranium resources from the ocean or salt lake. The separation and enrichment of uranium from the ocean and salt lake still face challenges such as low adsorption efficiency, difficult deployment and recovery of materials, etc. First, the concentration of uranium in the ocean and salt lake is very low, and there are a large number of competitive ions such as Fe, Cu, V, Ni, Zn, etc., which leads to low uranium extraction efficiency, complex subsequent purification process, and high uranium extraction cost. Second, the surface of the uranium extraction material or device is easily attached by a large number of microorganisms existing in seawater or salt lake, which makes it difficult for uranium to diffuse to the inside, further reducing the amount of uranium extraction; at the same time, the service life of the material and device is also easily reduced by the attachment of microorganisms and high salinity. SUMMARY

[0003] In order to solve the above problems, the present application provides a fiber material for uranium enrichment, a preparation method and application thereof. The fiber material for uranium enrichment uses fiber surface microstructure regulation technology to graft poly-amidoxime on the surface thereof and in-situ modify nanoparticles with broad-spectrum antibacterial properties to prepare a new type of uranium extraction fiber brush, i.e. the fiber material for uranium enrichment, so as to achieve the purpose of efficient uranium extraction from seawater and salt lake. The nanoparticles block or weaken the hydrogen bond interaction between high-density amidoxime, effectively inhibit the evolution phenomenon caused by too high grafting degree of traditional poly-amidoxime materials, improve the effective utilization rate of specific ligands, and thus improve the uranium extraction capacity. At the same time, the broad-spectrum bactericidal performance of the nanoparticles improves the antibioadhesion of the fiber material.

[0004] In the first aspect, the present application provides a fiber material for uranium enrichment, which comprises the following components: fiber, nitrile group-containing olefin compound, specific ligand-containing olefin compound and metal ion-containing substance, wherein the specific ligand can be complexed with the metal ion.

[0005] In some embodiments, the chemical structural formula of the nitrile group-containing olefin compound comprises

[0006] In some embodiments, the chemical structural formula of the specific ligand-containing olefin compound comprises

[0007] In some embodiments, the metal ion-containing substance includes one or more of copper acetate, copper sulfate, copper chloride, copper nitrate, silver nitrate, zinc sulfate, titanium chloride, iron sulfate, cadmium chloride, nickel chloride, and magnesium chloride.

[0008] In some embodiments, the copper acetate includes copper acetate monohydrate; a volume ratio of the nitrile group-containing olefin compound and the specific ligand-containing olefin compound is 4:1; and a mass of the copper acetate monohydrate is 0.5 g.

[0009] In some embodiments, the fiber material for uranium enrichment further includes a solvent for monomer polymerization; and the solvent for monomer polymerization includes acetonitrile, N,N-dimethylformamide, methanol, ethanol, toluene, dichloromethane, 1,4-dioxane, or chloroform.

[0010] In a second aspect, the present application provides a method for preparing a fiber material for uranium enrichment, comprising:

[0011] irradiation grafting on a surface of the fiber in the presence of a metal ion-containing substance, to obtain an acrylonitrile fiber complexed with metal ions on the surface;

[0012] treating the acrylonitrile fiber complexed with metal ions on the surface by hydroxylamine to obtain the fiber material for uranium enrichment; wherein the fiber material for uranium enrichment includes an amidoxime converted from a cyano group in the acrylonitrile fiber complexed with metal ions on the surface, and a corresponding nanoparticle converted from a metal ion in the acrylonitrile fiber complexed with metal ions on the surface.

[0013] In some embodiments, the step of irradiation grafting on a surface of the fiber in the presence of a metal ion-containing substance, to obtain an acrylonitrile fiber complexed with metal ions on the surface, includes: mixing the nitrile group-containing olefin compound, the specific ligand-containing olefin compound, and a solvent for monomer polymerization to obtain a first mixed solution; dissolving the metal ion-containing substance in the first mixed solution to obtain a second mixed solution; immersing the fiber in the second mixed solution; irradiation grafting the second mixed solution with the fiber immersed therein by a cobalt source at a preset irradiation dose rate, stopping irradiation when an irradiation dose reaches a preset dose and standing for a first preset time length; taking out and washing the fiber from the second mixed solution after standing for the first preset time length; and freeze-drying the washed fiber to a constant weight to obtain the acrylonitrile fiber complexed with metal ions on the surface.

[0014] In some embodiments, the step of treating the acrylonitrile fiber complexing metal ions on the surface by hydroxylamine to obtain the fiber material for enriching uranium comprises: soaking the acrylonitrile fiber complexing metal ions on the surface in N,N-dimethylformamide and standing for a second preset time length; adding hydroxylamine hydrochloride solution in a preset pH value range after standing for the second preset time length, taking out the acrylonitrile fiber complexing metal ions on the surface after reacting at room temperature for a third preset time length; washing the taken-out acrylonitrile fiber complexing metal ions on the surface, freeze-drying the washed acrylonitrile fiber complexing metal ions on the surface to obtain the fiber material for enriching uranium; wherein the preparation process of the hydroxylamine hydrochloride solution in the preset pH value range comprises dissolving hydroxylamine hydrochloride in deionized water, adding Na2CO3 to obtain a third mixed solution; adding sodium carbonate aqueous solution to the third mixed solution to obtain the hydroxylamine hydrochloride solution in the preset pH value range, wherein the preset pH value range is 6.9-7.1.

[0015] In a third aspect, the application provides the use of the fiber material for enriching uranium in seawater and salt lakes.

[0016] The application provides a fiber material for enriching uranium, a preparation method thereof, and an application thereof. The fiber material for enriching uranium is prepared by using fiber surface microstructure regulation technology, grafting polyamidoxime on the surface thereof, and in-situ modifying nanoparticles with broad-spectrum antibacterial properties, to prepare a new type of uranium extraction fiber brush, i.e., the fiber material for enriching uranium, so as to achieve the purpose of efficiently extracting uranium from seawater and salt lakes. The nanoparticles are used to block or weaken the hydrogen bond interaction between high-density amidoxy groups, effectively inhibit the evolution phenomenon of traditional polyamidoxime materials caused by excessively high grafting degree, improve the effective utilization rate of specific ligands, and thus improve the uranium extraction capacity. Meanwhile, the broad-spectrum bactericidal performance of the nanoparticles is used to improve the antibioadhesion property of the fiber material. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Exemplarily shown is a flow chart of another preparation method of the fiber material for enriching uranium according to some embodiments;

[0018] Figure 2 Exemplarily shown is a synthesis schematic diagram of copper-doped polyamidoxime grafted PE fiber according to some embodiments;

[0019] Figure 3 Exemplarily shown are schematic diagrams of material photos, mechanical properties, and infrared characterization according to some embodiments;

[0020] Figure 4 Exemplarily shown are XPS and XRD characterization diagrams of the material according to some embodiments;

[0021] Figure 5 Exemplary shows the scanning electron microscope (SEM) characterization results and element distribution maps provided according to some embodiments;

[0022] Figure 6 Exemplary shows a schematic diagram of material pore structure characterization provided according to some embodiments;

[0023] Figure 7 Exemplary shows a schematic diagram of the results of the solid-liquid ratio, kinetics, isotherm, and selective adsorption performance tests provided according to some embodiments;

[0024] Figure 8 Exemplary shows a relevant schematic diagram of the antibacterial performance of the material provided according to some embodiments;

[0025] Figure 9 Exemplary shows a schematic diagram of the test results of the regeneration performance of the material provided according to some embodiments. DETAILED DESCRIPTION

[0026] In the related art, the techniques for uranium enrichment mainly include chemical precipitation, membrane separation, ion exchange, adsorption, flotation, and biological enrichment. Compared with other methods, the adsorption method has been widely studied due to its low cost, simple operation, and universality. Therefore, various functional materials, such as fiber materials, membrane materials, and organic porous materials, have been developed and applied in uranium extraction research.

[0027] Membrane materials have been researched and applied in uranium extraction from seawater and salt lakes. In the related art, a kind of amine oxime group functionalized biomimetic membrane material with multiple pore sizes is provided (Nature Sustainability 2022, 5, 71-80). Using this pore structure, the biomimetic membrane allows rapid diffusion of uranyl ions, and the uranium adsorption capacity is 20 times higher than that of membrane materials with single pore size. Using a column adsorption system, the uranium adsorption capacity of this material in natural seawater can reach 9.03 mg U / g. In another related art, low-temperature polymerization is used to cross-link acrylonitrile, acrylic acid, and other monomers, and after freeze-drying, continuous super-macro-pore (10-100 mm) channels are obtained, which facilitate the rapid passage of seawater, and the compressive strength is 1.4-3.3 MPa (Journal of Materials Chemistry A 2023, 11, 10384-10395). In another related art, phenoxy imine is used to self-assemble into a large-area film (CSMCRI HOF-1) through molecular hydrogen bonds in pyridine, and the specific surface area is as high as 550 m 2 / g (Chem 2022, 8, 2749-2765). However, membrane materials still face the bottleneck of microbial viscosity, pollution, and blockage in practical application, and need to be cleaned regularly, which is complex to maintain.

[0028] Porous organic framework materials, such as covalent organic frameworks (COFs), metal-organic frameworks (MOFs), conjugated microporous / mesoporous polymers (CMPs), hydrogen-bonded organic frameworks (HOFs), etc., due to their adjustable chemical structure and pore structure, can improve the adsorption and anti-biofouling properties by rational design of building units. In one related technology, biphenyl is coupled to form a rigid skeleton, and amidoxime groups are well dispersed, and the utilization rate is increased from 10-20% of flexible skeleton to more than 60% (Chemical Science 2020, 11, 4747-4752). In another related technology, a benzoxadiazole-linked covalent organic framework is loaded onto the surface of a silicon-based material to obtain a BHMS sponge, and the solar evaporation rate can reach 1.39 kg·m -2 ·h -1 , which has ideal built-in structural hierarchy and elastic macroporous open cells, providing sufficient water transport (ACS Applied Materials & Interfaces 2021, 13, 31561-31568). However, such materials often have a relatively complex preparation process, expensive raw materials or catalysts, and difficulty in batch production. Moreover, such materials are mostly powdery or small particles, which have great limitations in engineering applications in seawater and salt lake uranium extraction.

[0029] Currently, poly(amino-oxime) fiber materials have become one of the most widely used materials for large-scale seawater uranium extraction due to their high uranium selectivity and good deployability and recycling performance. However, the adhesion of microorganisms to such materials in real seawater is serious, which greatly reduces their mechanical strength and adsorption capacity, resulting in an increase in the cost of uranium extraction. Recent studies have found that the adsorption of poly(amino-oxime) to uranium ions has "emergent phenomena", that is, when the surface grafting degree of the material exceeds a certain threshold, the adsorption capacity will show a nonlinear decline. Studies have shown that this phenomenon is due to the formation of hydrogen bonds between high-density amino-oxime groups, which reduces the hydrophilicity of the material and the utilization rate of the adsorption site (Physical Chemistry Chemical Physics 2019, 21, 554-560). To address this problem, related technologies have prepared a 3D hierarchical porous and high specific surface area poly(amino-oxime) fiber through an axial grafting strategy. This material has a 3.4-fold increase in uranium adsorption capacity compared to traditional methods of preparing poly(amino-oxime) fibers with similar grafting rates, which to some extent inhibits the "emergent phenomenon" (Energy & Environmental Science 2019, 12, 1979-1988). Therefore, precise regulation of the physical and chemical structure of poly(amino-oxime) to further suppress its "emergent phenomenon" and improve the anti-biofouling performance of the material is expected to significantly increase the adsorption capacity of the material and improve the service life of the material, thereby reducing the cost of uranium extraction.

[0030] Membrane materials are prone to clogging or contamination, and require regular cleaning and complex maintenance. Organic porous polymers can improve adsorption rate, adsorption capacity and selectivity by adjusting pore structure and ligands, but the preparation process of such materials is often complex, and the raw materials and catalysts used in the preparation are expensive, making it difficult to economically prepare materials for large-scale uranium extraction. Moreover, such materials are mostly in the form of powders or small particles, which have great limitations in large-scale seawater uranium extraction. Amino-oxime polymer fibers are currently the most widely used materials for large-scale seawater uranium extraction, but the strong hydrogen bonding between high-density amino-oxime groups significantly reduces their effective utilization rate, ultimately resulting in low uranium extraction capacity. At the same time, due to the serious microbial viscosity in seawater and salt lakes, amino-oxime fibers not only further reduce the uranium adsorption capacity, but also reduce their mechanical properties and reduce the number of repeated uses, increasing the cost of uranium extraction.

[0031] To solve the above technical problems, the embodiment of the present application provides a fiber material for enriching uranium, a preparation method and an application thereof. The fiber material for enriching uranium adopts a fiber surface microstructure regulation technology, grafts poly-amidoxime on the surface thereof, and in-situ modifies nanoparticles with broad-spectrum antibacterial performance, so as to prepare a new type of uranium extraction fiber brush, that is, the fiber material for enriching uranium, so as to achieve the purpose of efficiently extracting uranium from seawater and salt lakes. The nanoparticles are used to block or weaken the hydrogen bond effect between high-density amidoxime, effectively inhibit the evolution phenomenon of the traditional poly-amidoxime material caused by excessively high grafting degree, improve the effective utilization rate of specific ligands, and thus improve the uranium extraction capacity. Meanwhile, the broad-spectrum bactericidal performance of the nanoparticles is used to improve the antibioadhesion of the fiber material.

[0032] The embodiment of the present application provides a fiber material for enriching uranium, which comprises the following components: fiber, nitrile group-containing olefin compound, specific ligand-containing olefin compound and metal ion M-containing substance, wherein the specific ligand can be complexed with the metal ion.

[0033] In the embodiment of the present application, the fiber is a commercial high-strength fiber. The fiber comprises polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) or nylon (PA).

[0034] In some embodiments, the volume ratio of the nitrile group-containing olefin compound and the specific ligand-containing olefin compound is 2-8:1.

[0035] In some embodiments, the chemical structural formula of the nitrile group-containing olefin compound comprises

[0036] In some embodiments, the chemical structural formula of the specific ligand-containing olefin compound comprises

[0037] In some embodiments, the metal ion M-containing substance comprises one or more of copper acetate, copper sulfate, copper chloride, copper nitrate, silver nitrate, zinc sulfate, titanium chloride, iron sulfate, cadmium chloride, nickel chloride, magnesium chloride. The corresponding metal ion M can be copper ion, silver ion, zinc ion, titanium ion, iron ion, cadmium ion, nickel ion or magnesium ion. In addition, the metal ion-containing substance can also comprise a gold ion-containing substance. The corresponding nanoparticles converted from the metal ions included in the fiber material for enriching uranium generated subsequently can comprise copper nanoparticles, silver nanoparticles, zinc nanoparticles, titanium nanoparticles, iron nanoparticles, cadmium nanoparticles, nickel nanoparticles, magnesium nanoparticles and gold nanoparticles.

[0038] In some embodiments, the copper acetate comprises copper acetate monohydrate; the volume ratio of the nitrile group-containing olefin compound and the specific ligand-containing olefin compound is 4:1; and the mass of the copper acetate monohydrate is 0.5 g.

[0039] In some embodiments, the monomer polymerization solvent further comprises acetonitrile, N,N-dimethylformamide, methanol, ethanol, toluene, dichloromethane, 1,4-dioxane, or chloroform.

[0040] The embodiments of the present application also provide a preparation method of a fiber material for enriching uranium, comprising:

[0041] A fiber is used as a substrate, and a nitrile group-containing olefin compound and a specific ligand-containing olefin compound are used as polymerization monomers. Irradiation grafting is performed on the surface of the fiber in the presence of a substance containing metal ions M, to obtain acrylonitrile fiber complexed with metal ions on the surface (MPAN@Fiber).

[0042] The acrylonitrile fiber complexed with metal ions on the surface is treated by hydroxylamine to obtain a fiber material for enriching uranium (MPAO@Fiber). The fiber material for enriching uranium comprises amidoxime converted from the cyano group in the acrylonitrile fiber complexed with metal ions on the surface, and nanoparticles converted from the metal ions in the acrylonitrile fiber complexed with metal ions on the surface.

[0043] Figure 1 An example shows a flow chart of another preparation method of a fiber material for enriching uranium according to some embodiments.

[0044] In some embodiments, the step of using a fiber as a substrate, using a nitrile group-containing olefin compound and a specific ligand-containing olefin compound as polymerization monomers, and performing irradiation grafting on the surface of the fiber in the presence of a substance containing metal ions to obtain acrylonitrile fiber complexed with metal ions on the surface comprises:

[0045] The nitrile group-containing olefin compound, the specific ligand-containing olefin compound, and the monomer polymerization solvent are mixed to obtain a first mixed solution.

[0046] In one example, the nitrile group-containing olefin compound is acrylonitrile (AN), the specific ligand-containing olefin compound is acrylic acid (AA), and the monomer polymerization solvent is acetonitrile.

[0047] The substance containing the metal ions is dissolved in the first mixed solution to obtain a second mixed solution.

[0048] In one example, the substance containing the metal ions is copper acetate monohydrate.

[0049] immersed in the second mixed solution.

[0050] In one example, the fiber is polyethylene (PE) fiber.

[0051] The second mixed solution with the immersed fiber is irradiated grafting by using a cobalt source at a preset irradiation dose rate, and the irradiation is stopped when the irradiation dose reaches a preset dose and the fiber is rested for a first preset time. In one example, the preset irradiation dose rate is 15 Gy min-1, the preset dose is 100 kGy, and the first preset time is 16 h.

[0052] After the first preset time, the fiber is taken out of the second mixed solution and washed.

[0053] In some embodiments, the washing process of the removed fiber includes washing with DMF, ethanol and water in sequence; when washing with DMF, the process is using 30 mL of DMF each time and washing three times. For example, the removed fiber is washed with 30 mL of DMF for the first time, then washed with new 30 mL of DMF for the second time, and then washed with new 30 mL of DMF for the third time. Similarly, the ethanol and water are also used 30 mL each time and washed three times.

[0054] The washed fiber is freeze-dried to a constant weight to obtain acrylonitrile fiber with surface complexed metal ions.

[0055] In some embodiments, the step of treating the acrylonitrile fiber with surface complexed metal ions by hydroxylamine to obtain a fiber material for enriching uranium includes:

[0056] The acrylonitrile fiber with surface complexed metal ions is soaked in N,N-dimethylformamide and rested for a second preset time; after the second preset time, a hydroxylamine hydrochloride solution in a preset pH range is added, and the acrylonitrile fiber with surface complexed metal ions is taken out after reacting for a third preset time at room temperature. In one example, the second preset time is 2 h, and the third preset time is 72 h.

[0057] In one example, 1.0 g of the acrylonitrile fiber with surface complexed metal ions is soaked in N,N-dimethylformamide and rested for 2 h to allow it to swell fully. After 2 h of resting, 10 mL of a hydroxylamine hydrochloride solution in a preset pH range is added, and the acrylonitrile fiber with surface complexed metal ions is taken out after reacting for 72 h at room temperature.

[0058] The taken-out acrylonitrile fiber with surface complexed metal ions is washed, and the washed acrylonitrile fiber with surface complexed metal ions is freeze-dried to obtain a fiber material for enriching uranium.

[0059] In the embodiment of the present application, the process of cleaning the acrylonitrile fiber after taking out the surface complex metal ions includes alternating cleaning with ethanol and water; the process of alternating cleaning with ethanol and water includes first cleaning with 30 mL of ethanol, then cleaning with 30 mL of water, and then repeating twice.

[0060] The process of preparing the hydroxylamine hydrochloride solution in the preset pH value range includes dissolving hydroxylamine hydrochloride in deionized water, adding Na2CO3 to obtain a third mixed solution; adding an aqueous sodium carbonate solution to the third mixed solution to obtain a hydroxylamine hydrochloride solution in a preset pH value range, wherein the preset pH value range is 6.9-7.1. For example, 2.0 g of hydroxylamine hydrochloride is dissolved in 20 mL of deionized water, 1.0 g of Na2CO3 is added to obtain a third mixed solution. Then, 1M Na2CO3 aqueous solution is added to the third mixed solution to adjust the pH value of the hydroxylamine hydrochloride solution to 6.9-7.1.

[0061] The embodiment of the present application also provides the use of the fiber material for enriching uranium in seawater and salt lakes.

[0062] In the embodiment of the present application, the fiber material for enriching uranium is also subjected to adsorption test, repeated performance and stability test, and simulation seawater adsorption experiment.

[0063] Specifically, the process of adsorption test includes investigating the adsorption of the fiber material for uranium from the aspects of material dosage, adsorption kinetics, isotherm, selectivity, etc.

[0064] The process of repeated performance and stability test includes eluting and regenerating the fiber material with appropriate concentration of hydrochloric acid to investigate the repeatability of uranium extraction. The regenerated fiber material is characterized by infrared and SEM to investigate the stability of its chemical structure and micro-pore channel.

[0065] The process of simulation seawater adsorption experiment includes soaking the fiber material in seawater with 100 times additional concentration of U, V, Fe, Ni, Zn, Pb, Cr, Mn and Cd, and then dissolving the fiber material after adsorption equilibrium, and detecting the selectivity and adsorption amount in simulation seawater by ICP-OES (inductively coupled plasma atomic emission spectrometer).

[0066] The fiber material for enriching uranium in the embodiments of the present application is prepared by surface microstructure regulation technology, and poly-amidoxime is grafted on the surface of the fiber while metal nanoparticles with broad-spectrum antibacterial performance are modified in situ. The introduction of the metal nanoparticles can destroy the hydrogen bond effect between high-density amidoxime, effectively inhibit the development effect, and improve the effective utilization rate of amidoxime. On the basis of maintaining the mechanical strength of the fiber and the convenience of deployment, the adsorption performance is improved by increasing the grafting rate. At the same time, the antibacterial performance of the fiber material is improved, and the service life of the material is effectively improved by cutting off the microbial adhesion from the source.

[0067] The embodiments of the present application provide a fiber material for enriching uranium, a preparation method and applications thereof. The fiber material for enriching uranium is prepared by surface microstructure regulation technology, and poly-amidoxime is grafted on the surface of the fiber while nanoparticles with broad-spectrum antibacterial performance are modified in situ to prepare a new type of uranium extraction fiber brush with antibioadhesion, i.e., the fiber material for enriching uranium, so as to realize efficient uranium extraction from seawater and salt lakes. The nanoparticles are used to block or weaken the hydrogen bond effect between high-density amidoxime, effectively inhibit the development phenomenon of traditional poly-amidoxime materials due to excessively high grafting degree, improve the effective utilization rate of specific ligands, and thus improve the uranium extraction capacity. At the same time, the broad-spectrum bactericidal performance of the nanoparticles is used to improve the antibioadhesion of the fiber material. The fiber material with high strength and high adsorption performance can not only be used for uranium extraction in seawater and salt lakes, but also be applied to other resource or pollutant efficient separation fields.

[0068] The following will describe in detail how to prepare the fiber material for enriching uranium, and the characterization data, various performances and the like of the fiber material through specific embodiments.

[0069] Taking the fiber material MPAO@Fiber for enriching uranium as an example, the specific implementation is as follows:

[0070] (1) Preparation method of the fiber material for enriching uranium

[0071] (a) First, CuPAN@PE, i.e., acrylonitrile fiber complexed with metal ions, is prepared.

[0072] Copper acetate monohydrate (Cu(OAc)2·H2O) is dissolved in a mixed solution of acetonitrile (MeCN) containing acrylonitrile (AN) and acrylic acid (AA). Subsequently, 2.0 g of polyethylene fiber (PE fiber) is completely immersed in the above solution. Cobalt source is used for irradiation grafting (γ-ray irradiation). The irradiation dose rate is 15 Gy / min. -1, continuous irradiation dose of 100 kGy. After irradiation, the mixture was allowed to stand for 16 hours, and then the irradiated fiber was washed with DMF (3 x 30 mL), ethanol (3 x 30 mL), and water (3 x 30 mL) in sequence. The fiber was freeze-dried to constant weight to obtain CuPAN@PE.

[0073] (b) Then, CuPAO@PE, i.e., copper-doped polyamidoxime grafted PE fiber, was prepared.

[0074] 2.0 g of hydroxylamine hydrochloride was dissolved in 20 mL of deionized water, 1.0 g of Na2CO3 was added, and then the pH value of the hydroxylamine hydrochloride solution was adjusted to 6.9-7.1 with 1 M Na2CO3 aqueous solution to obtain a hydroxylamine aqueous solution, i.e., a hydroxylamine hydrochloride solution in a preset pH range was obtained.

[0075] 1.0 g of the prepared CuPAN@PE was weighed, immersed in 30 mL of DMF (N,N-dimethylformamide) and allowed to stand for 2 h for sufficient swelling. After swelling, 10 mL of the above-mentioned prepared hydroxylamine aqueous solution was added, and the reaction was carried out at room temperature for 72 h. After the reaction, the fiber was taken out and washed with ethanol (3 x 30 mL) and water (3 x 30 mL) alternately. The washed fiber was freeze-dried to obtain CuPAO@PE.

[0076] Figure 2 An exemplary synthesis schematic diagram of the copper-doped polyamidoxime grafted PE fiber according to some embodiments is shown.

[0077] In order to better show the performance of the fiber material in the embodiments of the present application, PAN@PE-2, CuPAN@PE-1, CuPAN@PE-2, CuPAN@PE-3, CuPAN@PE-4, CuPAN@PE-5 and CuPAN@PE-6 were prepared under the conditions of different mass of copper acetate monohydrate and different volume ratios of acrylonitrile (AN) and acrylic acid (AA) using the same method of preparing acrylonitrile fiber for surface complexation of metal ions (i.e., the preparation method in (a) above). Then, PAO@PE, CuPAO@PE-1, CuPAO@PE-2, CuPAO@PE-3, CuPAO@PE-4, CuPAO@PE-5 and CuPAO@PE-6 were prepared using the same method of preparing copper-doped polyamidoxime grafted PE fiber (i.e., the preparation method in (b) above). The different parameters used in the preparation of the seven samples are shown in Table 1.

[0078] Table 1

[0079]

[0080] Table 1 a: Here the grafting rate is the weight increase of the fiber after grafting relative to the weight before grafting, containing grafted cyano, carboxylic acid and copper species. Irradiation conditions: 2.0 g PE fiber, 15 Gy / min, 100 kGy.

[0081] Table 1 b: Pre-adsorption capacity of different materials after ammoximation under the same conditions (adsorption conditions: Co(U) = 11.9 mg / L, material dosage 0.05 g / L, pH 8 ± 0.1, 300 h, 298.15 K).

[0082] In addition, 0.5 g Cu(OAc) 2· H2O was prepared using the same method of preparing copper-doped polyaminoxime grafted PE fiber (i.e. the preparation method in (b)).

[0083] (c) Pre-adsorption test

[0084] The seven materials in Table 1 (i.e. the seven samples in Table 1) were dispersed in a uranyl nitrate solution at a proportion of 0.05 mg / mL, 11.9 ppm, pH = 8.0, and after 300 h of shaking at room temperature, the supernatant was taken and filtered, the uranium concentration in the filtrate was tested by ICP-OES, and the adsorption capacity of the material was calculated accordingly.

[0085] Table 1 AN: When the AA dosage ratio is 4:1, three materials CuPAO@PE-1~3 are prepared by changing the amount of copper acetate added, corresponding to the amount of copper acetate added of 0.25 g, 0.5 g, and 0.75 g respectively, and the pre-adsorption results of different materials are shown in Table 1. Among them, CuPAO@PE-2 has the highest pre-adsorption capacity. When the optimal amount of copper acetate is determined, the ratio of acrylonitrile to acrylic acid is optimized. When the amount of copper acetate added is 0.5 g, CuPAO@PE-2 and CuPAO@PE-4~6, corresponding to the AN:AA volume ratio of 4:1, 1:0, 8:1, and 2:1 respectively, are used to evaluate the effect of monomer dosage ratio (AN:AA) on adsorption performance. It is found from the pre-adsorption experiment results that when the AN:AA dosage volume ratio is 4:1, the material has the optimal adsorption performance. Therefore, CuPAO@PE-2 is mainly used for subsequent characterization and adsorption experiments.

[0086] (2) Characterization of CuPAO@PE-2

[0087] Figure 3 Exemplary schematic diagrams of material photos, mechanical properties and infrared characterization provided according to some embodiments are shown.

[0088] From the macroscopic morphological characteristics of the material, it can be clearly found that the copper-doped polyacrylonitrile acrylic fiber (CuPAN@PE-2) presents a uniform light green color Figure 3A). After hydroxylamine treatment, the color of the product CuPAO@PE-2 changed to obvious yellow brown Figure 3 B), which may be due to the following conversion process: hydroxylamine first reduces the coordinated Cu 2+ to cuprous state (Cu + ), and then under the action of air oxidation, part of the cuprous ions are further converted into cuprous oxide (CuO, red) or cupric oxide (CuO, black) nanoparticles. The coexistence of these two copper oxides results in the final yellow brown color of the material. Through tensile test, the tensile strength of CuPAO@PE-2 reaches 169 MPa Figure 3 C), and the material with a cross section of about 1 mm 2 can bear the weight of 4.5 L of water Figure 3 D), meeting the strength requirements of seawater uranium extraction.

[0089] The copper content of the prepared fiber material CuPAN@PE-2 was 1.25wt% by using concentrated nitric acid digestion method combined with ICP-MS technology, and after amidoxime modification, the copper content of CuPAO@PE-2 was significantly reduced to 0.21wt% (measured by digestion sample). This change is mainly due to the reduction of part of the copper ions to low valence copper after hydroxylamine, which changes the coordination structure of cyanide or carboxyl group, resulting in the loss of part of the copper.

[0090] Figure 3 E shows the infrared spectra of different materials, where a represents PAN@PE-2, b represents CuPAN@PE-2, c represents PAO@PE, and d represents CuPAO@PE-2. Compared with PE fiber, the infrared spectrum of grafted polyacrylonitrile fiber CuPAN@PE-2 appears new infrared absorption peaks at 3059-3695 cm -1 , 2236 cm -1 , 1713 cm -1 and 1640 cm -1 , which are respectively attributed to the -OH peak of carboxyl group, cyanide peak, -C=O anti-symmetric stretching vibration peak and symmetric stretching vibration peak of carboxyl group. After amidoxime, the cyanide peak at 2236 cm -1 in the infrared spectrum of CuPAO@PE-2 basically disappears, while the peak at 3326 cm -1 significantly enhances, which is due to the generation of NH2 in amidoxime. The peak at 1640 cm -1 enhances due to the generation of C=N characteristic peak after amidoxime. At the same time, characteristic absorption peaks of sodium carboxylate appear at 1565 cm -1 and 1446 cm -1 .

[0091] Figure 4Exemplary XPS and XRD characterization figures of the materials provided according to some embodiments are shown. Refer to Figure 4 , Figure 4 A is the N1s fine spectrum of XPS, Figure 4 B is the O1s fine spectrum of XPS, Figure 4 C is the Cu2p fine spectrum of XPS, Figure 4 D is the XRD figure. In Figure 4 A, Figure 4 D, a represents PAN@PE-2, b represents CuPAN@PE-2; c represents PAO@PE; d represents CuPAO@PE-2; e represents CuPAN@PE-3; f represents CuPAO@PE-3. In Figure 4 A, the N1s binding energy of the cyano group (-C≡N) in CuPAN@PE-2 is located at 399.6 eV, which is shifted from that of PAN@PE-2 (399.0 eV). This phenomenon indicates that the copper ion is involved in the coordination of the cyano group. After hydroxylamine treatment, the N1s spectra of PAO@PE and CuPAO@PE-2 can be deconvoluted into two characteristic peaks: amine group (-C-NH) nitrogen at 400.0 eV and oxime group (-C=N-OH) nitrogen at 399.4 eV. This result indicates that during the amidoxime reaction, part of the cyano group originally coordinated with the copper ion in CuPAN@PE-2 not only undergoes chemical transformation, but also releases the metal coordination, ultimately forming free amidoxime groups without complexing copper. This result is consistent with the copper content determination results by ICP-MS, further confirming the structural evolution of the material during modification.

[0092] Figure 4 In B, the O1s peak of PAN@PE-2 can be split into a C=O peak of carboxylic acid at 533.3 eV and an OH peak of carboxylic acid at 531.9 eV, as well as a COO - resonance oxygen peak. In the O1s fine spectrum of CuPAN@PE-2, the two peaks are shifted due to the coordination of copper ions with COOH or COO - After hydroxylamine treatment, the O1s peaks of PAO@PE and CuPAO@PE-2 can be split into an oxime group peak at 532.7 eV and a carboxylate peak at 531.3 eV. This indicates that the cyano group and the carboxyl group are successfully converted into the oxime group and the carboxylate.

[0093] The above results show that the polyethylene fiber surface is successfully grafted with acrylonitrile and acrylic acid copolymer, and is converted into amidoxime groups and carboxylate, respectively, during the amidoxime process.

[0094] Because the copper content of CuPAN@PE-2 and CuPAO@PE-2 is very low, the Cu2pXPS fine spectra of these two materials are too noisy for copper valence state analysis. Therefore, CuPAN@PE-3 and CuPAO@PE-3 were selected for analysis to determine the valence state and content of copper in the materials. Figure 5 As shown in C, Cu2p of CuPAN@PE-3 3 / 2 and 2p 1 / 2 The peaks are at 933.2 and 953.5 eV, corresponding to divalent copper (Cu). 2+ Characteristic peaks

[23] After hydroxylamine treatment, Cu2p 3 / 2 and 2p 1 / 2 Each peak can be decomposed into two, corresponding to divalent copper (933.0 and 953.2 eV) and low-valent copper (monovalent and zero-valent copper, 931.8 and 951.7 eV), respectively, with low-valent copper accounting for 73% of the total copper content. These results indicate that the copper ions complexed on the polymer underwent a reduction reaction under the action of hydroxylamine. X-ray diffraction (XRD) was used to supplement the material to analyze the types of copper in the material. Figure 5 As shown by line f in D, characteristic peaks of elemental copper, Cu2O, and CuO can be observed. This suggests that copper in CuPAO@PE exists in the forms of Cu(0), Cu2O, and CuO. The presence of Cu(0) and Cu2O is attributed to hydroxylamine reducing some divalent copper to monovalent and zero-valent copper.

[0095] Figure 5 Exemplary examples illustrate scanning electron microscopy (SEM) characterization results and elemental distribution maps provided according to some embodiments, wherein... Figure 5 A represents the scanning electron microscope image of PE. Figure 5 B represents the scanning electron microscope image of CuPAN@PE-2. Figure 5 C represents the scanning electron microscope image of CuPAO@PE-2; Figure 5 D represents the elemental distribution diagram of CuPAO@PE-2; Figure 5 E represents the high-resolution transmission electron microscopy elemental distribution map of CuPAO@PE-2.

[0096] See Figure 5 A- Figure 5 C. The polyethylene fiber surface is smooth, but after copolymer grafting, the material shows more wrinkles, indicating that acrylonitrile and acrylic acid are uniformly grafted onto the material surface. After hydroxylamine treatment, the lamellar wrinkles on the material surface are more obvious. This can be verified by elemental distribution mapping (…). Figure 6 D) Further observation revealed that C, N, O, and Cu elements were uniformly dispersed on the material surface, confirming that the copolymer had been uniformly grafted onto the substrate surface. To further investigate the distribution of copper in the material, a high-resolution transmission electron microscope (HR-TEM) was used. Figure 6E) Elemental surface scanning was performed on the CuPAO@PE-2 fiber graft layer. This analysis showed that C, N, O, and Cu elements exhibited high spatial overlap at the microscale, and copper aggregation points were detected. Combined with XPS and XRD results, the presence of nano-copper and nano-copper oxides in the material can be inferred.

[0097] Figure 6 The illustration shows a schematic diagram of material pore structure characterization according to some embodiments, in which the pore structure properties of the material are systematically characterized using surface area analysis (BET) and mercury intrusion porosimetry (MIP) techniques. Figure 6 A shows the nitrogen adsorption and desorption curves for PAO@PE and CuPAO@PE-2. Figure 6 B represents the BET aperture distribution; Figure 6 C represents the mercury pressure curve; Figure 6 D represents the pore size distribution in mercury indentation method.

[0098] exist Figure 6 In component A, the specific surface area of ​​CuPAO@PE-2 is 0.32 m². 2 g-1, compared to undoped copper PAO@PE (0.25m) 2 The g-1 concentration increased by 28%, indicating that the introduction of copper effectively improved the surface properties of the material. This was further demonstrated by combining BET and MIP pore size distribution analysis. Figure 7 B and Figure 7 D) It was found that CuPAN@PE-2 mainly exhibits a macroporous structure with a pore size of 4.0 μm, which is due to the physical stacking between fibers; while CuPAO@PE-2, in addition to retaining micron-sized macropores, also significantly increased the mesoporous structure with a pore size of 5.2 nm. This evolution of pore structure can be attributed to the metal-organic coordination effect changing the aggregated state structure of the polymer, thereby forming a richer mesoporous network inside the fibers.

[0099] (3) Adsorption performance study

[0100] 5 mg of the material was weighed and dispersed in a uranyl solution, then fixed on a shaker at 120 rpm and 298.15 K until adsorption equilibrium was reached. After adsorption, the uranium concentration in the solution before and after adsorption was quantitatively analyzed by high-resolution inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma fluorescence spectrometry (ICP-OES). The equilibrium adsorption capacity (qe) and adsorption efficiency (SE) of uranium were calculated according to formulas (1) and (2):

[0101]

[0102]

[0103] Among them + eC0(mg / L) and C0(mg / L) represent the equilibrium concentration and initial concentration of uranium, respectively. M represents the weight of the material (g), and V represents the volume of the test solution (L).

[0104] Figure 7 Example 1 shows the results of solid-liquid ratio, kinetics, isotherm, and selective adsorption performance tests provided according to some embodiments. The results of the effect of material dosage on the adsorption performance of CuPAO@PE-3 are shown in the schematic diagram. Figure 7 A is a schematic diagram of the effect of adsorbent dosage on the adsorption performance of CuPAO@PE-3, Figure 7 As shown in A, the uranium adsorption capacity of CuPAO@PE-3 gradually decreases with the increase of material dosage, while the adsorption efficiency gradually increases with the increase of material dosage. When the material dosage reaches 0.6 mg / mL, the adsorption efficiency reaches 97.6%. Figure 7 B and Figure 7 C is a schematic diagram of the adsorption kinetics test results of different materials, with an adsorption condition of C0(U) = 11.9 mg / L, 0.05 g / L material, pH 8 ± 0.1, 300 h, and 298.15 K. a represents CuPAO@PE-1, b represents CuPAO@PE-2, c represents CuPAO@PE-3, d represents CuPAO@PE-4, e represents CuPAO@PE-5, f represents CuPAO@PE-6, g represents PAO@PE, and h represents CuNPs. As shown in C, the adsorption kinetics of CuPAO@PE-1 to CuPAO@PE-6 with a grafting rate of about 560% is similar to that of PAO@PE with a grafting rate of about 100%, and the equilibrium time is close to 30 hours. Figure 7 As shown in B and 7C, the PAO@PE with a grafting rate of about 100% and CuPAO@PE-1 to CuPAO@PE-6 with a grafting rate of about 560% show similar adsorption kinetics, and the equilibrium time is close to 30 hours. Among them, the adsorption performance of PAO@PE is the worst, but it is still slightly higher than that of the copper species (copper, cuprous oxide, and copper hydroxide) obtained by treating copper acetate with hydroxylamine, indicating that the uranium extraction capacity of the material mainly comes from the polyamidoxime grafted on the surface of the fiber, and the loading of nano-copper can significantly improve the adsorption performance of the material. Figure 7 D is a schematic diagram of the adsorption isotherm test results of the material, with an adsorption condition of C0(U) = 11.9-32 mg / L, 0.05 g / L material, pH 8 ± 0.1, 300 h, and 298.15 K. Figure 7 E is a schematic diagram of the selectivity of CuPAO@PE-3 in simulated seawater, with an adsorption condition of C0(U) = 2.4-32 ppm, material dosage 0.01 g / L, pH 8 ± 0.1, 300 h, and 298 K. Figure 8 F is a schematic diagram of the copper content of CuPAO@PE grafting layers with different grafting rates and the adsorption performance of CuPAO@PE with different grafting rates and PAO@PE, with an adsorption condition of simulated seawater: ion concentration is 100 times the corresponding ion concentration of real seawater, material dosage 0.001 g / L, adsorption time 600 h, and 298 K.

[0105] The formula for the first-order dynamic equation is as follows:

[0106]

[0107] Where q e and q t These are the adsorption amounts at equilibrium and at a certain moment, respectively, k1(min) -1 Then ) represents the first-order dynamic constant, which can be expressed as log(q) e -q t For a linear fit plot of t, the slope and intercept of the line are k1 and q, respectively. e t is the adsorption time.

[0108] The formula for the second-order dynamic equation is as follows:

[0109]

[0110] In the formula, k2 represents the second-order kinetic constant, and can be obtained by... The result was obtained by linear fitting to t.

[0111] The adsorption kinetics of PAO@PE and CuPAO@PE-1~6 were studied using first- and second-order kinetic models. The kinetic parameters are listed in Table 2, which shows the first- and second-order kinetic fits for PAO@PE and CuPAO@PE-1~6. A large R0 2 The values ​​indicate that the kinetics of PAO@PE and CuPAO@PE-1 to 6 are more consistent with the pseudo-second-order model, proving that chemisorption is dominant throughout the adsorption process.

[0112] Table 2

[0113]

[0114] To evaluate the adsorption capacity of the materials, uranium adsorption isotherms of CuPAO@PE-3 and PAO@PE were studied in solutions with different uranium concentrations (2.4 ppm to 250 ppm) at pH 8.0 ± 0.1 and 298 K. Figure 8 D). Adsorption isotherm data were analyzed using the Langmuir and Freundlich models, with the following formulas and detailed parameters in Table 3:

[0115]

[0116] Where q max (mg / g) represents the maximum adsorption capacity, while b(L / mg) represents the Langmuir constant, whose value is related to the affinity of the binding site for capturing the target ion. (The last part, "through C," appears to be an incomplete sentence or fragment and is left untranslated.) e / q e For C eThe slope and intercept of the linear fitting can be used to calculate q max and b values, and the relevant parameters are shown in Table 3.

[0117] The Freundlich model refers to multilayer adsorption of target ions on the material, and the formula is as follows:

[0118]

[0119] where K F (mol 1-n L n / g) represents the Freundlich constant, and n is the distribution coefficient, and the two values can be calculated by the slope and intercept of the linear fitting of logq e The linear fitting of logC e is performed, and the slope and intercept are used to calculate, and the relevant parameters are shown in Table 3. Table 3 shows the results of Langmuir adsorption isotherm and Freundlich adsorption isotherm fitting of different materials.

[0120] Table 3

[0121]

[0122] A higher R 2 value indicates that the adsorption isotherm of CuPAO@PE-3 and PAO@PE conforms to the Langmuir model, indicating that the adsorption sites are uniformly distributed on the surface of the material and uranium is monolayer adsorbed (Table 3). After Langmuir model fitting, the maximum adsorption capacity of PAO@PE and CuPAO@PE-3 is 662.2 and 819.6 mg U / g, respectively. Table 4 lists the adsorption capacity of different materials for uranium under similar conditions. It can be seen that the uranium adsorption capacity of CuPAO@PE-3 is higher than that of most reported adsorption materials.

[0123] Table 4

[0124]

[0125]

[0126] In Table 4 a : maximum adsorption capacity in uranium solution;

[0127] In Table 4 b : standard seawater, the concentrations of uranium and other detected ions are 100 times the concentrations of real seawater.

[0128] The simulated seawater solution of U, V, Fe, Ni, Zn, Pb, Cr, Mn, Cd with the concentration 100 times of the real seawater was prepared, and CuPAO@PE-3 was added at the solid-liquid ratio of 0.001 mg / mL. After adsorption equilibrium, the sample was nitrified. The uranium concentration in the nitrified solution was tested by ICP-MS after dilution, and the adsorption amount was calculated. As shown in Table 2, the adsorption amount of uranium in the simulated seawater was 28.4 mg / g, which was 1.1 times of vanadium and 11.7 times of iron. Figure 8 As shown in Table 2, the selectivity of the optimized functional fiber material CuPAO@PE-3 to uranium in the simulated seawater was obviously better than that of other ions, and the adsorption amount of uranium reached 28.4 mg / g, which was 1.1 times of vanadium and 11.7 times of iron. The above results show that the prepared fiber material has good selectivity to uranium in seawater.

[0129] In the amidoxime fiber, the "evolution effect" is used to express that the adsorption amount of the material does not continuously increase linearly with the increase of the grafting rate of the material, but after the grafting rate reaches a certain threshold, the increase rate slows down or even the adsorption amount decreases. In the embodiment of the present application, copper ions are introduced synchronously during the grafting of the polymer, and the chemical structure of the polymer is changed by using the coordination and reduction reaction of copper ions, so as to "weaken" the strong interaction between the amidoxime ligands, inhibit the "evolution effect", and improve the adsorption amount. The preparation ratio of the optimized functional fiber is adjusted, a series of functional fibers CuPAO@PE-7-14 with different grafting rates and PAO@PE-7-14 without loaded copper are prepared by adjusting the ratio of the polymerization monomer and the PE fiber. See Table 5 for details. Table 5 shows the PAO@PE and CuPAO@PE materials with different grafting rates.

[0130] Table 5

[0131]

[0132]

[0133] In Table 5, a: irradiation condition: 2.0 g of PE fiber, AN: AA = 4:1, V (AN+AA) : V MeCN = 19:31, 15 Gy min -1 , 100 kGy.

[0134] In Table 5, b: after hydroxylamine treatment, the copper content of the fiber after digestion was determined by ICP-OES.

[0135] CuPAO@PE-7~14 were nitrified, and the copper concentration of the fiber nitrification solution was determined by ICP-OES to obtain the copper loading of different fibers. As shown in Table 5, the copper content in CuPAO@PE-7~14 is relatively close, about 0.19~0.24wt%. Uranium adsorption was carried out on fibers with different grafting rates. The uranium extraction amount of the fiber without loading of nano-copper gradually increased with the increase of the grafting rate. When the grafting rate increased to 149.9%, the uranium adsorption amount was 57.2mg / g, and further increasing the grafting rate showed a downward trend, i.e. the threshold of the evolution effect of PAO@PE was 149.9%. For the material loaded with nano-copper oxide, the uranium adsorption amount began to decrease only when the amidoxime grafting rate reached 712.0%, and the threshold of the evolution effect was increased by 4.3 times, and the adsorption amount reached 165.0mg / g. The above results show that the loading of nano-copper on the surface of the amidoxime fiber can effectively inhibit the "evolution effect" of high-density amidoxime, increase the utilization rate of amidoxime, and thus increase the uranium adsorption amount of the material.

[0136] (6) Anti-biofouling

[0137] Figure 8 The relevant diagrams showing the antibacterial performance of the material provided according to some embodiments are exemplarily shown. The antibacterial performance of the material on two common marine bacteria (Escherichia coli and Staphylococcus aureus) was tested by microdilution method. It can be observed that the bacteria solution treated by CuPAO@PE-2 can better inhibit the growth of Escherichia coli and Staphylococcus aureus under the same dilution multiple, as shown in Figure 8 A, Figure 9 A is the view of the antibacterial effect of CuPAO@PE-2 and PAO@PE-2. The antibacterial rates of the two materials were calculated by plate counting method. The antibacterial rates of CuPAO@PE-2 on Escherichia coli and Staphylococcus aureus were 97.4% and 99.9% respectively, which were higher than 72.3% and 93.6% of PAO@PE-2, indicating that doping copper can effectively improve the antibacterial performance of the material, which is helpful to improve the anti-biofouling performance of the seawater uranium extraction material in seawater, Figure 9 B, Figure 9 B is the diagram of the antibacterial rates of CuPAO@PE-2 and PAO@PE-2.

[0138] (7) Regeneration performance

[0139] Figure 9 The test result diagram of the regeneration performance of the material provided according to some embodiments is exemplarily shown. Figure 9 A is the result diagram of the regeneration test of CuPAO@PE-2. Figure 9 B is the result diagram of the cycle adsorption test of CuPAO@PE-2, Figure 9The conditions of the corresponding test method are C0(U) = 11.9 ppm, 0.01 g / L adsorbent, pH 8.0 ± 0.1, 298 K, 300 h. Figure 9 C is the infrared contrast of CuPAO@PE-2 before adsorption and after 10 cycles.

[0140] The regeneration performance of the material was investigated using different concentrations of HCl, Na2CO3, EDTA, and Na2EDTA solution as eluent. ​ A) When the molar concentration was 0.1 M, the elution rate of Na2CO3 on CuPAO@PE-2 was significantly higher than that of HCl (78%), EDTA (49%), and Na2EDTA (76%), which could reach 100%. Therefore, 0.1 M Na2CO3 solution was selected as the eluent for subsequent regeneration and cyclic adsorption tests. After 10 adsorption-desorption cycles, CuPAO@PE-2 still retained 83.9% of the original adsorption performance ​ B), and the infrared spectra of CuPAO@PE-2 before and after 10 cycles did not change significantly ​ C), which indicated that using 0.1 M Na2CO3 solution as the eluent, the material had good regeneration performance.

[0141] It is easy for those skilled in the art to understand that the above advantageous modes can be freely combined and superimposed without conflict. The above is only a preferred embodiment of the present application and does not limit the present application. Any modification, equivalent replacement, and improvement made within the spirit and principles of the present application should be included in the protection scope of the present application. The above is only a preferred embodiment of the present application, and it should be noted that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, which should be considered as the protection scope of the present application.

Claims

1. A fibrous material for uranium enrichment, characterized in that, It comprises the following components: fibers, nitrile-containing olefin compounds, olefin compounds containing specific ligands, and substances containing metal ions, wherein the specific ligands can complex with the metal ions.

2. The fibrous material for uranium enrichment according to claim 1, characterized in that, The chemical structural formula of the nitrile-containing olefin compound includes 3. The fibrous material for uranium enrichment according to claim 1, characterized in that, The chemical structural formula of the olefin compound containing a specific ligand includes 4. The fibrous material for uranium enrichment according to claim 1, characterized in that, The metal ion-containing substances include one or more of the following: copper acetate, copper sulfate, copper chloride, copper nitrate, silver nitrate, zinc sulfate, titanium chloride, ferric sulfate, cadmium chloride, nickel chloride, and magnesium chloride.

5. The fiber material according to claim 4, characterized in that, The copper acetate comprises copper acetate monohydrate; the volume ratio of the nitrile-containing olefin compound to the olefin compound containing a specific ligand is 4:1; the mass of the copper acetate monohydrate is 0.5g.

6. The fibrous material for uranium enrichment according to claim 1, characterized in that, It also includes solvents used for monomer polymerization; the solvents used for monomer polymerization include acetonitrile, N,N-dimethylformamide, methanol, ethanol, toluene, dichloromethane, 1,4-dioxane or chloroform.

7. The method for preparing the fibrous material for uranium enrichment according to any one of claims 1-6, characterized in that, include: Using fibers as a base and olefin compounds containing nitrile groups and olefin compounds containing specific ligands as polymerization monomers, the surface of the fibers is irradiated and grafted in the presence of substances containing metal ions to obtain acrylonitrile fibers with surface complexed metal ions. The acrylonitrile fibers with surface-complexed metal ions are treated with hydroxylamine to obtain a fiber material for uranium enrichment; wherein the fiber material for uranium enrichment includes a metallo-oxime converted from the cyano group in the acrylonitrile fibers with surface-complexed metal ions, and metal ions in the acrylonitrile fibers with surface-complexed metal ions converted into corresponding nanoparticles.

8. The method according to claim 7, characterized in that, The step of obtaining acrylonitrile fibers with surface-complexed metal ions by irradiation grafting on the surface of the fibers, using fibers as a substrate and olefin compounds containing nitrile groups and olefin compounds containing specific ligands as polymerizing monomers, under the condition of the presence of a substance containing metal ions, includes: The nitrile-containing olefin compound, the olefin compound containing a specific ligand, and the solvent used for monomer polymerization are mixed to obtain a first mixed solution; the substance containing the metal ions is dissolved in the first mixed solution to obtain a second mixed solution; the fiber is immersed in the second mixed solution; the second mixed solution without the fiber is subjected to irradiation grafting using a cobalt source at a preset irradiation dose rate, and irradiation is stopped when the irradiation dose reaches the preset dose and the fiber is left to stand for a first preset time; after standing for the first preset time, the fiber is removed from the second mixed solution and cleaned; the cleaned fiber is freeze-dried to constant weight to obtain acrylonitrile fiber with surface complexed metal ions.

9. The method according to claim 8, characterized in that, The step of treating the acrylonitrile fibers with surface-complexed metal ions with hydroxylamine to obtain a fiber material for uranium enrichment includes: The acrylonitrile fibers with surface-complexed metal ions are immersed in N,N-dimethylformamide and allowed to stand for a second preset time. After standing for the second preset time, a hydroxylamine hydrochloride solution within a preset pH range is added, and the reaction is carried out at room temperature for a third preset time. The acrylonitrile fibers with surface-complexed metal ions are then removed. The removed acrylonitrile fibers with surface-complexed metal ions are then washed and freeze-dried to obtain a fiber material for uranium enrichment. The preparation process of the hydroxylamine hydrochloride solution within the preset pH range includes dissolving hydroxylamine hydrochloride in deionized water, adding Na2CO3 to obtain a third mixed solution, and adding an aqueous sodium carbonate solution to the third mixed solution to obtain a hydroxylamine hydrochloride solution within a preset pH range, wherein the preset pH range is 6.9–7.

1.

10. The application of the fibrous material for uranium enrichment according to any one of claims 1-6 in uranium enrichment in seawater and salt lakes.

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