Composite materials and methods of making and uses of composite materials

Abstract

The application discloses a composite material and a preparation method and application thereof. The composite material takes carbon felt as a matrix, and CdS and modified polyacrylonitrile are loaded on the carbon felt matrix, and the modified groups in the modified polyacrylonitrile are amidoxime groups and hydroxyl groups. The composite material has high extraction efficiency on uranium in seawater.

Description

TECHNICAL FIELD

[0001] The present application relates to a composite material and a preparation method and use of the composite material. BACKGROUND

[0002] Natural uranium is a basic raw material for the development of nuclear industry, which can be used to manufacture nuclear weapons and nuclear power fuel in military field, and can be used as fuel for nuclear power reactors in national economic construction. As an important nuclear fuel for nuclear power operation, the supply of uranium is the key to guarantee the sustainable development of nuclear power.

[0003] The natural uranium resources in China are relatively scarce, and the development of unconventional uranium resources should be sought and developed while developing land uranium resources. Seawater is an important and promising unconventional uranium resource. Uranium in seawater mainly exists in the form of hexavalent uranyl in uranyl carbonate or neutral charge derivatives, and the concentration is low, with a large number of competitive ions.

[0004] The mainstream method of uranium extraction from seawater is adsorption, but it has many challenges such as insufficient extraction capacity and long adsorption equilibrium time. Compared with the traditional physical and chemical adsorption process, electrochemical seawater uranium extraction has the advantages of fast reaction rate and strong anti-interference ability. The key to electrochemical seawater uranium extraction is the research and development of electrode materials. At present, in the research of electrochemical seawater uranium extraction, the electrode materials are mainly graphene, amide oxime, chitosan and the like, but there are problems of complex preparation process. SUMMARY

[0005] One object of the present application is to provide a composite material which has a high extraction efficiency for uranium in seawater. Further, the composite material is easy to recycle. Another object of the present application is to provide a preparation method of a composite material, which has a high extraction efficiency for uranium in seawater and is easy to recycle. Still another object of the present application is to provide a use of the composite material.

[0006] The objects of the present application are achieved by the following technical solutions.

[0007] In one aspect, the present application provides a composite material, which has a carbon felt as a matrix, and CdS and modified polyacrylonitrile are loaded on the carbon felt matrix, and the modified groups in the modified polyacrylonitrile are amine oxime groups and hydroxyl groups.

[0008] The modified polyacrylonitrile can extract uranium in seawater. CdS is a narrow band gap photocatalytic material, has high photosensitive response in the visible light region, and can reduce hexavalent uranium to tetravalent uranium under visible light excitation. CdS is a powder material, and has the problems of difficult separation and recovery in practical application, so that the application is limited. The CdS is introduced into the polyacrylonitrile modified composite material in the application, the photoelectric synergistic effect is utilized to improve the extraction efficiency of the material on uranium in electrochemical seawater uranium extraction, and the problem of difficult recovery of CdS is solved.

[0009] In another aspect, the application provides a preparation method of the composite material, comprising the following steps:

[0010] (1) loading CdS and polyacrylonitrile on carbon felt to obtain carbon felt loaded with CdS and polyacrylonitrile;

[0011] (2) modifying the polyacrylonitrile in the carbon felt loaded with CdS and polyacrylonitrile by amidoxime to obtain a modified product;

[0012] (3) modifying the amidoxime modified polyacrylonitrile in the modified product by hydroxyl to obtain the composite material.

[0013] According to the preparation method of the application, preferably, in step (1), the carbon felt is placed in a mixed solution containing CdS and polyacrylonitrile, and then ultrasonic treatment is performed to obtain the carbon felt loaded with CdS and polyacrylonitrile. CdS and polyacrylonitrile can be used in a powder state.

[0014] According to the preparation method of the application, preferably, the solvent of the mixed solution is selected from one or more of N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide; and the mass ratio of CdS to polyacrylonitrile in the mixed solution is (0.05-0.8):1.

[0015] In some embodiments, the mass ratio of CdS to polyacrylonitrile in the mixed solution is (0.1-0.5):1.

[0016] The mass ratio of the solvent to polyacrylonitrile in the mixed solution can be (10-50):1; preferably (20-40):1.

[0017] In some embodiments, the CdS is stirred and mixed with the solvent, and then stirred and mixed with the polyacrylonitrile for 1-5 hours, preferably 2-4 hours, to obtain the mixed solution containing CdS and polyacrylonitrile. The polyacrylonitrile can be dried polyacrylonitrile.

[0018] In the present application, the carbon felt can be placed in the mixed solution for multiple times for loading. The CdS and polyacrylonitrile can be uniformly and effectively loaded on the carbon felt by using ultrasonic method. In some embodiments, the carbon felt is placed in the mixed solution, and is ultrasonically treated for 5-50 min, preferably 15-30 min, and then taken out and dried to obtain a first loading. The first loading is placed in the mixed solution, and is ultrasonically treated for 5-50 min, preferably 15-30 min, and then taken out and dried to obtain a second loading. The second loading is placed in the mixed solution, and is ultrasonically treated for 5-50 min, preferably 15-30 min, and then taken out and dried to obtain the carbon felt loaded with CdS and polyacrylonitrile.

[0019] According to the preparation method of the present application, preferably, the method further comprises the step of adding the first solution containing the sulfide and the basic reagent into the second solution containing the water-soluble cadmium salt, and then reacting at 10-60°C to obtain CdS. In some embodiments, the first solution can be added into the second solution by using a constant flow pump. Preferably, the reaction temperature is 20-40°C. The reaction time can be 0.5-8 h, preferably 1-5 h.

[0020] In some embodiments, the method comprises the step of filtering and then drying the first product obtained by the reaction of the first solution and the second solution, thereby obtaining CdS.

[0021] According to the preparation method of the present application, preferably, the sulfide is an alkali metal sulfide, the basic reagent is an alkali metal hydroxide, the solvent of the first solution is water, the water-soluble cadmium salt is cadmium chloride, and the solvent of the second solution is selected from one or more of water and monohydric alcohol containing 1-6 carbon atoms. More preferably, the solvent of the second solution is a mixture of water and monohydric alcohol.

[0022] Examples of the alkali metal hydroxide include, but are not limited to, sodium hydroxide and potassium hydroxide. Examples of the alkali metal sulfide include, but are not limited to, sodium sulfide and potassium sulfide. Examples of the monohydric alcohol containing 1-6 carbon atoms include, but are not limited to, methanol, ethanol, propanol, isopropanol, and butanol.

[0023] According to the preparation method of the present application, preferably, the mass ratio of the sulfide to the water-soluble cadmium salt is (0.3-2):(0.2-1.5), and the mass ratio of the sulfide to the basic reagent is (0.3-2):(8-20). More preferably, the mass ratio of the sulfide to the water-soluble cadmium salt is (0.5-1.5):(0.3-0.8).

[0024] In the first solution, the mass ratio of the sulfide to the solvent is (0.3-2):(400-850), preferably (0.5-1.5):(500-750).

[0025] In the first solution, the mass ratio of the sulfide to the basic reagent is (0.3-2):(8-20); preferably (0.5-1.5):(10-15).

[0026] In the second solution, the mass ratio of the water-soluble cadmium salt to the solvent is (0.2-1.5):(550-900); preferably (0.3-0.8):(600-830).

[0027] In the second solution, the mass ratio of the water to the monohydric alcohol is (500-850):(15-35); preferably (550-800):(20-32).

[0028] According to the preparation method of the present application, preferably, in step (2), the carbon felt loaded with CdS and polyacrylonitrile is reacted with hydroxylamine hydrochloride in the presence of a basic condition and a potassium salt. Specifically, the reaction can be carried out in the presence of water. In some embodiments, the reaction can be carried out in a constant temperature shaker.

[0029] Examples of the potassium salt include, but are not limited to, potassium chloride. The basic condition can be provided by an alkali metal hydroxide. Examples of the alkali metal hydroxide include, but are not limited to, sodium hydroxide, potassium hydroxide.

[0030] In step (2), the reaction temperature can be 60-90°C; preferably 65-85°C. The reaction time can be 12-30h; preferably 15-25h.

[0031] In step (2), the mass ratio of hydroxylamine hydrochloride to the potassium salt can be (2-7):(0.2-1.5); preferably (3-6):(0.3-1.2).

[0032] In step (2), the mass ratio of hydroxylamine hydrochloride to the alkali metal hydroxide can be (2-7):(1.2-5); preferably (3-6):(1.5-4).

[0033] In step (2), the mass ratio of hydroxylamine hydrochloride to water can be (2-7):(65-110); preferably (3-6):(70-100).

[0034] In some embodiments, the water, hydroxylamine hydrochloride and the potassium salt are stirred, and then the alkali metal hydroxide is added and stirred to obtain a reaction liquid to be reacted. The reaction liquid to be reacted and the carbon felt loaded with CdS and polyacrylonitrile are reacted to obtain a modified product.

[0035] The stirring time of the water, hydroxylamine hydrochloride and the potassium salt can be 0.2-2h; preferably 0.5-1h.

[0036] The stirring time after adding the alkali metal hydroxide can be 0.2-2h; preferably 0.5-1h.

[0037] According to the preparation method of the present application, preferably, in step (3), the modified product is reacted with an alkali metal hydroxide solution to obtain a composite material. In some embodiments, the reaction is carried out in a constant temperature oscillator. Examples of the alkali metal hydroxide include, but are not limited to, potassium hydroxide, sodium hydroxide.

[0038] The concentration of the alkali metal hydroxide solution can be 0.05-0.4 mol / L; preferably 0.1-0.3 mol / L.

[0039] In step (3), the reaction temperature can be 30-70℃; preferably 35-60℃. The reaction time can be 0.2-3 h; preferably 0.5-2 h.

[0040] In some embodiments, the method further comprises the following steps: the second product obtained by reacting the modified product with the alkali metal hydroxide solution is washed with water, and then dried to obtain the composite material. The water washing can be carried out once or multiple times. For example, 3-8 times, and for example, 5-6 times.

[0041] In another aspect, the present application provides the use of the above-mentioned composite material or the composite material obtained by the above-mentioned method as an electrode material for extracting uranium from seawater.

[0042] The composite material of the present application can be used as an electrode for extracting uranium from seawater by electrochemical method, and has high extraction efficiency. The present application loads the powder-like CdS on the carbon felt, which is convenient for recycling. DETAILED DESCRIPTION

[0043] The present application will be further described below in conjunction with specific examples, but the scope of protection of the present application is not limited thereto.

[0044] The test method is described below:

[0045] Uranium extraction efficiency: the composite material is used as the working electrode, a platinum sheet is used as the counter electrode, and a saturated calomel electrode is used as the reference electrode. A 300W xenon lamp is used as the light source. The distance between the electrolytic cell and the light source is 10 cm. The electrolyte is a simulated seawater composed of natural seawater and uranyl tricarbonate. The concentration of uranium in the simulated seawater is 3.3 mg / L, and the pH is 8.1. The electrolysis is carried out under the irradiation of the light source. The electrolysis conditions are: temperature 25℃, set voltage -3-0V, working electrode voltage -3V, reference electrode voltage 0V, and time 4h. The concentration of uranium is tested according to HJ700-2014.

[0046] Examples 1 to 4

[0047] CdCl2 and alcohol solvent were added into distilled water A and stirred to obtain a second solution. Na2S and alkaline reagent were added into distilled water B and stirred to obtain a first solution. The first solution was slowly added into the second solution by a constant flow pump, and then reacted at T1 for t1 to obtain a first reaction product. The first reaction product was filtered and then dried to obtain CdS.

[0048] CdS was mixed with an organic solvent and then mixed with dry polyacrylonitrile powder for t2 to obtain a mixture containing CdS and polyacrylonitrile. A 30mm×30mm carbon felt was placed in the mixture and ultrasonically treated for t3, and then taken out and dried to obtain a first loading. The first loading was placed in the mixture and ultrasonically treated for t4, and then taken out and dried to obtain a second loading. The second loading was placed in the mixture and ultrasonically treated for t5, and then taken out and dried to obtain a carbon felt loaded with CdS and polyacrylonitrile.

[0049] Distilled water C, hydroxylamine hydrochloride and potassium chloride were stirred for t6, and then an alkali hydroxide was added and stirred for t7 to obtain a reaction solution. The reaction solution and the carbon felt loaded with CdS and polyacrylonitrile were placed in a constant temperature shaker and reacted at T2 for t8 to obtain a modified product.

[0050] The modified product and a sodium hydroxide solution were placed in a constant temperature shaker and reacted at T3 for t9 to obtain a second reaction product. The second reaction product was washed with water and then dried to obtain a composite material.

[0051] Specific parameters and uranium extraction efficiency of the composite material are shown in Table 1.

[0052] Table 1

[0053]

[0054]

[0055] Note: Distilled water A, distilled water B and distilled water C all represent distilled water. The letters after the distilled water only distinguish the distilled water added in different steps and have no other meanings.

[0056] The present application is not limited to the above-mentioned embodiments, and any modification, improvement or replacement conceived by those skilled in the art without departing from the essential content of the present application falls within the scope of the present application.

Claims

1. A method for preparing a composite material, characterized in that, Includes the following steps: Add 0.48g of cadmium chloride and 24g of ethanol to 600g of distilled water A, stir well to obtain the second solution; add 0.8g of sodium sulfide and 10g of potassium hydroxide to 500g of distilled water B, stir well to obtain the first solution. The first solution was slowly added to the second solution using a constant flow pump, and then reacted at 30°C for 3 hours to obtain the first reaction product. The first reaction product was filtered and then dried to obtain CdS. 0.2 g of CdS was stirred and mixed with 30 g of dimethyl sulfoxide, and then stirred and mixed with 1 g of dried polyacrylonitrile powder for 2 h to obtain a mixture containing CdS and polyacrylonitrile; a 30 mm × 30 mm carbon felt was placed in the mixture, sonicated for 25 min, and then dried to obtain the first loading; the first loading was placed in the mixture, sonicated for 20 min, and then dried to obtain the second loading; the second loading was placed in the mixture, sonicated for 15 min, and then dried to obtain a carbon felt loaded with CdS and polyacrylonitrile. 80g of distilled water C, 4g of hydroxylamine hydrochloride and 1g of potassium chloride were stirred for 0.7h, and then 3.2g of potassium hydroxide was added and stirred for 1h to obtain the reaction solution. The reaction solution and carbon felt loaded with CdS and polyacrylonitrile were placed in a constant temperature shaker and reacted at 75℃ for 20h to obtain the modified product. The modified product and a 0.15 mol / L sodium hydroxide solution were placed in a constant temperature shaker and reacted at 45 °C for 1.5 h to obtain the second reaction product. The second reaction product was washed with water 6 times and then dried to obtain the composite material.

2. Use of a composite material obtained by the preparation method of claim 1 as an electrode material for extracting uranium from seawater.

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