Carbon-coated iron-nickel composite material, preparation and irradiation regeneration method and application

Abstract

The application provides a carbon-coated iron-nickel composite material, a preparation and irradiation regeneration method and application. The composite material is modified by iron-nickel, the active sites on the surface of the composite material are increased, and the adsorption capacity of the composite material to salt and oxidants in wastewater is enhanced. The addition of thiourea realizes the co-doping of sulfur and nitrogen, and improves the stability of iron-nickel in the composite material and the activation capacity of the composite material to the adsorbed oxidants. The composite material not only has good salt separation performance, but also has the capacity of adsorbing and activating oxidants. When the carbon-coated iron-nickel composite material provided by the application is used as an electrode material for irradiation regeneration, through twice irradiation treatment, the pollutant molecules and salt ions on the surface of the electrode are cracked or oxidized, separated from the surface of the electrode, and the iron-nickel active sites of the carbon-coated iron-nickel composite material are regenerated. Compared with the existing alkali regeneration or pyrolysis regeneration method, the regeneration energy consumption of the application is low, the efficiency is high, the application is environment-friendly, and the electrode is not damaged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic electrode materials and preparation technology, and particularly relates to a carbon-coated iron-nickel composite material, a preparation and irradiation regeneration method and application. BACKGROUND

[0002] High-salinity organic wastewater is a difficult problem in the field of industrial wastewater treatment. The high salinity in high-salinity organic wastewater can significantly affect the activity of microorganisms and reduce the treatment effect of biological processes. At the same time, high salinity can also reduce the treatment effect of advanced oxidation processes. How to economically and effectively treat high-salinity organic wastewater is a problem that needs to be solved in the field of industrial wastewater treatment.

[0003] High salinity is the main reason that restricts the existing wastewater treatment process to treat high-salinity organic wastewater. If effective separation of high salinity and water can be achieved, the treatment effect of conventional wastewater treatment processes will be greatly improved. The commonly used methods for separating salts in wastewater include membrane method and electric adsorption method. The membrane method can separate salts while also retaining part of the organic matter, forming high-concentration salt organic wastewater; at the same time, the membrane method also has the problem of membrane clogging. The electric adsorption method can also separate salts and water, and the key lies in the performance of the electrode material. The existing electrode material exhibits good salt separation performance, but does not have the ability to adsorb and activate oxidants. This makes the salt separated by the electric adsorption method lack of purity, which to some extent limits the further application of the electric adsorption method in the treatment of high-salinity organic wastewater.

[0004] At the same time, the economic and effective regeneration of electrode materials has always been a difficult problem in the field of materials. At present, the commonly reported regeneration methods in research include alkali regeneration and pyrolysis regeneration. Alkali regeneration achieves regeneration by destroying the bond between the material and the organic pollutants, and has low regeneration efficiency and generates a large amount of waste liquid. Pyrolysis regeneration requires high energy consumption. SUMMARY

[0005] In view of the above problems existing in the prior art, the present application provides a carbon-coated iron-nickel composite material, a preparation and irradiation regeneration method and application. The carbon-coated iron-nickel composite material provided by the present application uses iron-nickel to modify the carbon material, increasing the active sites on the surface of the composite material. The abundant active sites can effectively adsorb salts and reduce the energy barrier required for activating oxidants. The addition of thiourea realizes the simultaneous doping of sulfur and nitrogen in the material. The presence of sulfur can improve the electron transfer capacity of the composite material, which further enhances the adsorption capacity of the active sites for salts and the activation capacity of the adsorbed oxidants. The activated oxidants can increase the ability of the electric adsorption process to remove organic pollutants, thereby improving the purity of the salts separated by the electric adsorption method. The doping of nitrogen improves the stability of iron-nickel in the composite material, making the composite material suitable for various complex sewage environments. In addition, the present application provides an irradiation regeneration method, which is simple to operate and has the ability to realize large-scale regeneration. The specific application content is as follows:

[0006] In a first aspect, the present application provides a preparation method of carbon-coated iron-nickel composite material, which comprises:

[0007] S1, dropwise adding a potassium ferricyanide solution into a cobalt chloride solution, and after standing for 10-12 hours, filtering and washing the cobalt chloride solution, and collecting the solid material, which is dried to obtain a Fe-Ni Prussian blue analogue;

[0008] S2, simultaneously adding the Fe-Ni Prussian blue analogue and a carbon source in a mass ratio of 1:2-1:4 into a proper amount of deionized water, and after ultrasonic stirring and drying, mixing with thiourea uniformly, and then transferring into a tube furnace, calcining at 550-900℃ for 1-2.5 hours, and cooling to obtain the carbon-coated iron-nickel composite material.

[0009] Optionally, the molar ratio of the potassium ferricyanide solution to the cobalt chloride solution is 1:1-2.

[0010] Optionally, the mass ratio of the Fe-Ni Prussian blue analogue to the carbon source is 1:2-1:4.

[0011] Optionally, the mass ratio of the total mass of the Fe-Ni Prussian blue analogue and the carbon source to the mass of the thiourea is 1:5-1:20.

[0012] Optionally, in step S1, the drying is selected at a temperature of 60-80℃ for 10-12 hours.

[0013] In step S2, the drying is selected at a temperature of 60-80℃ for 10-12 hours.

[0014] Optionally, the calcination is a staged temperature rising calcination, which comprises: rising the temperature to 550℃ at a rate of 1-5℃ / min, and continuing the calcination for 1-1.5 hours, then rising the temperature to 900℃ at a rate of 5-10℃ / min, and continuing the calcination for 0.5-1 hour.

[0015] Optionally, the carbon source is graphene, modified graphene, biochar or modified biochar.

[0016] In a second aspect, the present application provides a carbon-coated iron-nickel composite material obtained by the preparation method of the first aspect.

[0017] In a third aspect, the present application provides an application of the carbon-coated iron-nickel composite material obtained by the preparation method of the first aspect, which is used as an electrode material for removing salt in wastewater by electro-adsorption.

[0018] In a fourth aspect, the present application provides a method for regenerating the carbon-coated iron-nickel composite material obtained by the method of the first aspect, which is used as an electrode material for removing salt from wastewater by electro-adsorption, and the electrode material is regenerated by the following method, which comprises:

[0019] The used carbon-coated iron-nickel composite material is placed in a proper amount of deionized water, separated after the first irradiation treatment, and then placed in a mixed solution composed of water and ethanol in a volume ratio of 1:2-1:5, transferred to a vacuum drying oven for drying after the second irradiation treatment, and the regeneration is completed.

[0020] The irradiation sources for the first irradiation treatment and the second irradiation treatment include an electron accelerator, 60 Co or 137 Cs;

[0021] The dose of the first irradiation treatment and the second irradiation treatment is between 5 and 50 kGy.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] The present application provides a method for preparing a carbon-coated iron-nickel nanoparticle composite material, which comprises adding a certain amount of potassium ferricyanide dropwise into a certain amount of cobalt chloride solution to obtain a Fe-Ni Prussian blue analogue, mixing the Fe-Ni Prussian blue analogue with a carbon source and thiourea in a certain proportion, and calcining the obtained solid powder mixture in a tube furnace to obtain the carbon-coated iron-nickel composite material after natural cooling. The preparation method is green, environmentally friendly, low in cost, simple in process, and easy to realize mass production.

[0024] The present application also provides a carbon-coated iron-nickel nanoparticle composite material and its application. When the material is used as an electrode for electro-adsorption and acts on wastewater containing oxidants, the iron-nickel modification increases the active sites on the surface of the electrode, enhances the adsorption capacity of the electrode for salt in the wastewater, and at the same time, reduces the energy barrier required by the oxidants in the activation system. The activated oxidants increase the ability of the electro-adsorption process to remove organic pollutants. In addition, the addition of thiourea introduces sulfur and nitrogen into the composite material at the same time. Sulfur is a polyvalent element with abundant electrons, which can improve the electron transfer capacity and electron exchange capacity of the electrode material, thereby further promoting the activation of the adsorbed oxidants. The electrode material not only has good salt separation performance, but also has the ability to adsorb and activate oxidants. The presence of nitrogen makes the iron-nickel in the composite material complex with nitrogen to form a more stable structure, effectively preventing material loss or failure caused by iron-nickel dissolution during actual use.

[0025] The application further provides an irradiation regeneration method of the carbon-coated iron-nickel nanoparticle composite material. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0027] Figure 1 A flow chart of the preparation method of the carbon-coated iron-nickel composite material provided by the embodiment of the present application is shown;

[0028] Figure 2 An XRD graph of the carbon-coated iron-nickel composite material provided by the embodiment of the present application is shown;

[0029] Figure 3 An XRD graph of the carbon-coated iron-nickel composite material after irradiation regeneration provided by the embodiment of the present application is shown. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, any product identical or similar to the present application obtained by anyone under the inspiration of the present application or by combining the present application with other prior art features falls within the protection scope of the present application. In addition, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0031] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0032] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of this specification.

[0033] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0034] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The primary objective of this invention is to provide a method for preparing carbon-coated iron-nickel composite materials. Figure 1 A flowchart illustrating the preparation method of carbon-coated iron-nickel composite material provided in an embodiment of the present invention is shown, as follows: Figure 1 As shown, the preparation method includes:

[0036] S1. Potassium ferricyanide solution was added dropwise to cobalt chloride solution, and then the cobalt chloride solution was filtered, washed and dried to obtain Fe-Ni Prussian blue analogue;

[0037] S2. The Fe-Ni Prussian blue analogue and the carbon source in a mass ratio of 1:2-1:4 are added to an appropriate amount of deionized water. After ultrasonic stirring and drying, the mixture is then mixed evenly with thiourea and transferred to a tube furnace for calcination at 550-900℃ for 1-2.5 hours. After cooling, carbon-coated iron-nickel composite material is obtained.

[0038] In specific implementation, the present application adds a certain amount of potassium ferricyanide drop by drop into a certain amount of cobalt chloride solution to make it precipitate and generate a solid blue precipitate, Fe-Ni Prussian blue analogue, which is collected after filtration, deionized water washing and drying in an oven. The obtained solid is added into a certain amount of deionized water together with a carbon source, and then is uniformly mixed by ultrasonic stirring and dried in an oven to remove water. Further, thiourea is mixed with the dried solid (Prussian blue and carbon source mixture) in a certain proportion, and then is ground to make it uniformly mixed. The obtained solid powder is calcined at high temperature in a tube furnace. After calcination, the product is naturally cooled, washed with deionized water and dried in an oven to obtain the final carbon-coated iron-nickel composite material.

[0039] In some embodiments, the molar ratio of potassium ferricyanide solution and cobalt chloride solution is 1:1-2, and preferably the molar ratio of potassium ferricyanide solution and cobalt chloride solution is 1:1.5.

[0040] In some embodiments, the mass ratio of Fe-Ni Prussian blue analogue and carbon source is 1:2-1:4, and preferably the mass ratio of Fe-Ni Prussian blue analogue and carbon source is 1:3.

[0041] In some embodiments, the mass ratio of the total mass of Fe-Ni Prussian blue analogue and carbon source to the mass of thiourea is 1:5-1:20, and preferably the mass ratio of the total mass of Fe-Ni Prussian blue analogue and carbon source to the mass of thiourea is 1:10.

[0042] In some embodiments, the selected temperature for drying Fe-Ni Prussian blue analogue is 60-80℃, and the time is 10-12h; the selected temperature for drying the mixture of Fe-Ni Prussian blue analogue and carbon source is 60-80℃, and the time is 10-12h.

[0043] In specific implementation, the calcination is a staged temperature rising calcination, which is divided into two stages. In the first stage, the temperature is raised to 550℃ at a rate of 1-5℃ / min for 1-1.5h, during which the carbon source and thiourea are pyrolyzed and decomposed to generate a large amount of gas, which promotes the thermal polymerization of iron-nickel particles. In the second stage, the temperature is raised to 900℃ at a rate of 5-10℃ / min, and continues to be calcined for 0.5-1h, during which the iron-nickel particles gradually increase and form a certain grain structure. At the same time, the carbon layer coated on the surface of the iron-nickel particles continues to pyrolyze at high temperature to form certain pores and uneven surfaces. These pores and uneven surface morphology can provide more active sites.

[0044] In some embodiments, the preferred temperature-programmed calcination is as follows: increase the temperature to 550℃ at a rate of 3℃ / min, calcine for 1h, then increase the temperature to 900℃ at a rate of 5℃ / min, and continue to calcine for 1h.

[0045] The preparation method of the carbon-coated iron-nickel nanoparticle composite material provided by the application is green, low in cost, simple in process, and easy to implement in mass production.

[0046] In a second aspect, the application provides a carbon-coated iron-nickel composite material obtained by the preparation method of the first aspect.

[0047] In a third aspect, the application provides an application of the carbon-coated iron-nickel composite material obtained by the preparation method of the first aspect, which is used as an electrode material for removing salt from wastewater by electro-adsorption.

[0048] In specific implementation, the carbon-coated iron-nickel nanoparticle composite material provided by the first aspect of the application is used as an electrode material for electro-adsorption. When the obtained electrode is used to treat wastewater containing oxidants, the iron-nickel modification increases the active sites on the surface of the electrode, enhances the adsorption capacity of the electrode for salt in the wastewater, and reduces the energy barrier required for the oxidant (such as hydrogen peroxide) in the activation system. The active species generated by the activated oxidant can decompose organic matter in the salt adsorbed by the electrode, thereby improving the purity of the salt obtained by electro-adsorption. In addition, the addition of thiourea introduces sulfur into the electrode material. Sulfur is a multi-valent element with abundant electrons, which can improve the electron transfer capacity and electron exchange capacity of the electrode material, thereby further promoting the activation of the adsorbed oxidant. As a result, the electrode material not only has good salt separation performance, but also has the ability to adsorb and activate the oxidant, which enables the electro-adsorption method to be further developed and applied in the treatment of high-salt organic wastewater.

[0049] In a fourth aspect, the application provides a regeneration method for the carbon-coated iron-nickel composite material obtained by the preparation method of the first aspect, which is used as a component material of an electrode for removing salt from wastewater by electro-adsorption. After the electrode material is regenerated, the method comprises the following steps:

[0050] The used carbon-coated iron-nickel composite material is placed in a certain volume of deionized water, and the separated material after irradiation treatment is placed in a mixed solution composed of water and ethanol in a volume ratio of 1:2-1:5. After irradiation treatment, the material is transferred to a vacuum drying box for drying to achieve regeneration.

[0051] In some embodiments, the irradiation source of the irradiation treatment includes an electron accelerator, 60 Co or 137 Cs; and the dose of the irradiation treatment is between 5 and 50 kGy.

[0052] The present application adopts twice irradiation treatment, the first irradiation treatment (oxidation treatment), the pollutants on the electrode surface and salt ions are cracked or oxidized to a certain extent by means of irradiation, thereby reducing the adsorption capacity of the electrode surface, and separating from the electrode surface; the second irradiation treatment (reduction treatment) promotes the regeneration of the iron-nickel active site of the carbon-coated iron-nickel composite material. Compared with the existing alkali regeneration and pyrolysis regeneration methods, the regeneration method provided by the present application has low energy consumption, high efficiency, is friendly to the environment, and will not damage the electrode.

[0053] In order to enable those skilled in the art to more clearly understand the present application, the carbon-coated iron-nickel composite material, the preparation and irradiation regeneration method and application described in the present application are described in detail through the following examples.

[0054] Example 1:

[0055] 20ml 0.1M iron cyanide solution is added dropwise to 20ml 0.15M solution, aged in air for 12h, filtered, washed with deionized water for 3 times, and prussian blue analogues are obtained. Then, it is placed in a 60℃ oven and dried for 12h. 0.5g of dried prussian blue solid and 1.5g of chitosan are placed in 50ml deionized water, ultrasonic for 10min, then stirred for 1h, and then dried in an 80℃ oven for 12h. 1g of dried solid is mixed with 10g of thiourea solid, and ground uniformly. The ground powder is placed in a tube furnace. Under the condition of nitrogen, it is heated to 550℃ at a rate of 3℃ / min and kept for 1h, then heated to 900℃ at a rate of 5℃ / min and kept for 1h, and after natural cooling, the obtained solid is washed with deionized water for 3 times and placed in a 60℃ oven for drying. The obtained solid is the carbon-coated iron-nickel composite material.

[0056] Figure 2 The XRD pattern of the carbon-coated iron-nickel composite material provided by the embodiment of the present application is shown as follows: Figure 2 The XRD diffraction composition analysis result is shown as follows, the Fe 0 The XRD image of BC can obviously see the characteristic peaks corresponding to FeNi and carbon, which indicates that the carbon-coated iron-nickel composite material is successfully prepared in this embodiment.

[0057] The prepared carbon-coated iron-nickel composite material is used for adsorbing salt in wastewater, 0.5g of the used carbon-coated iron-nickel composite material is added to 30ml of ethanol and 10ml of deionized water mixed solution, and irradiation treatment is carried out by using a Co-60 source, the absorbed dose is 30kGy, and after the treated electrode is recovered by centrifugation, it is placed in a 60℃ vacuum drying oven for drying, and the irradiation regeneration process is completed.

[0058] Figure 3The XRD pattern of the carbon-coated iron-nickel composite material after irradiation regeneration provided by the embodiment of the present application is shown in Figure 2. Figure 3 As shown in Figure 2, the XRD pattern of the carbon-coated iron-nickel composite material after irradiation regeneration can clearly see that the characteristic peak intensity of FeNi and carbon after regeneration increases, indicating that the carbon-coated iron-nickel composite material can be successfully regenerated in this embodiment.

[0059] Embodiment 2

[0060] 20ml 0.1M iron cyanide solution was added dropwise to 20ml 0.15M solution, and after aging in air for 12h, it was filtered, washed with deionized water for 3 times, and a Prussian blue analogue was obtained. Then, it was placed in a 60℃ oven for drying for 12h. 0.5g of the dried Prussian blue solid and 1g of graphene were placed in 50ml of deionized water, ultrasonicated for 10min and stirred for 1h, and then dried in an 80℃ oven for 12h. 1g of the dried solid was mixed with 20g of thiourea solid, and ground uniformly. The ground powder was placed in a tube furnace. Under nitrogen, it was heated to 550℃ at a rate of 5℃ / min and kept for 1h, and then heated to 900℃ at a rate of 10℃ / min and kept for 1h, and after natural cooling, the obtained solid was washed with deionized water for 3 times and placed in a 60℃ oven for drying, and the obtained solid was the carbon-coated iron-nickel composite material.

[0061] The prepared carbon-coated iron-nickel composite material was used for electric adsorption of salt in wastewater, 0.5g of the used carbon-coated iron-nickel composite material was added to a mixed solution of 30ml of ethanol and 10ml of deionized water, and was treated by irradiation using a Co-60 source, with an absorbed dose of 30kGy. After centrifugal recovery, the treated electrode was dried in a 60℃ vacuum drying oven, and the irradiation regeneration process was completed.

[0062] The XRD pattern of the carbon-coated iron-nickel composite material obtained in this embodiment, and the XRD pattern of the carbon-coated iron-nickel composite material after irradiation regeneration are consistent with those shown in Figure 2 of Embodiment 1, and will not be repeated here. Figure 2 、 Figure 3

[0063] Embodiment 3

[0064] ​20ml 0.1M potassium ferricyanide solution was added dropwise to 20ml 0.2M solution, after aging in air for 10h, the Prussian blue analogue was obtained by filtration, deionized water washing 3 times, then placed in an oven at 80℃ drying 12h. Take 0.5g dried Prussian blue solid and 2g modified graphene in 50ml deionized water, ultrasonic 10min, then stirring 1h, then drying in an oven at 80℃ for 12h. Take 1g dried solid and mix with 15g thiourea solid, grind evenly. Put the ground powder into a tube furnace. Under the condition of nitrogen, heat to 550℃ at 3℃ / min, keep for 1h, then heat to 900℃ at 5℃ / min, keep for 1h, after natural cooling, the obtained solid is washed with deionized water 3 times and placed in a 60℃ oven to dry, the obtained solid is carbon-coated iron-nickel composite material.

[0065] The prepared carbon-coated iron-nickel composite material was used for electric adsorption of salt in wastewater, 0.5g of the used carbon-coated iron-nickel composite material was added to a mixed solution of 30ml ethanol and 10ml deionized water, and was treated by Co-60 source irradiation with an absorbed dose of 30kGy. The treated electrode was recovered by centrifugation and dried in a 60℃ vacuum drying oven to complete the irradiation regeneration process.

[0066] The XRD pattern of the carbon-coated iron-nickel composite material obtained in this example, and the XRD pattern of the carbon-coated iron-nickel composite material after irradiation regeneration are consistent with those given in Figure 2 、 Figure 3 of Example 1, which will not be repeated here.

[0067] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in the specification.

[0068] For the method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the order of the described actions, because according to the present application, certain steps can be performed in other order or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily necessary for the present application.

[0069] The carbon-coated iron-nickel composite material, the preparation and irradiation regeneration method and the application provided by the present application are described in detail above. The principles and implementation manners of the present application are described by using specific examples in this paper. The above examples are only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method for preparing a carbon-coated iron-nickel composite material, characterized in that, The preparation method includes: S1. Potassium ferricyanide solution was added dropwise to nickel chloride solution and allowed to stand for 10-12 h. The nickel chloride solution was then filtered and washed. The collected solid material was dried to obtain Fe-Ni Prussian blue analogue. S2. The Fe-Ni Prussian blue analogue with a mass ratio of 1:2 to 1:4 and the carbon source are added to an appropriate amount of deionized water. After ultrasonic stirring and drying, it is mixed evenly with thiourea and then transferred to a tube furnace for calcination at 550-900 °C for 1-2.5 h. After cooling, carbon-coated iron-nickel composite material is obtained. The carbon source is graphene or biochar.

2. The method for preparing carbon-coated iron-nickel composite material according to claim 1, characterized in that, The molar ratio of the potassium ferricyanide solution to the nickel chloride solution is 1:1-2.

3. The method for preparing carbon-coated iron-nickel composite material according to claim 1, characterized in that, The mass ratio of the Fe-Ni Prussian blue analog to the carbon source is 1:2 to 1:

4.

4. The method for preparing carbon-coated iron-nickel composite material according to claim 1, characterized in that, The total mass ratio of the Fe-Ni Prussian blue analogue and the carbon source to the thiourea is 1:5 to 1:

20.

5. The method for preparing carbon-coated iron-nickel composite material according to claim 1, characterized in that, In step S1, the drying temperature is selected as 60-80 ℃, and the time is 10-12 h; In step S2, the drying temperature is selected as 60-80 ℃ and the time is 10-12 h.

6. The method for preparing carbon-coated iron-nickel composite material according to claim 1, characterized in that, The calcination is a segmented heating calcination, which includes: heating to 550 ℃ at 1-5 ℃ / min, calcining for 1-1.5 h, then heating to 900 ℃ at 5-10 ℃ / min, and continuing to calcine for 0.5-1 h.

7. A carbon-coated iron-nickel composite material obtained by the preparation method according to any one of claims 1-6.

8. The application of a carbon-coated iron-nickel composite material obtained by any one of the preparation methods according to claims 1-6, characterized in that, The carbon-coated iron-nickel composite material is used as an electrode material for electro-adsorption to remove salt from wastewater.

9. A method for irradiating and regenerating carbon-coated iron-nickel composite materials obtained by the preparation method according to any one of claims 1-6, characterized in that, The carbon-coated iron-nickel composite material is used as an electrode material for electro-adsorption removal of salts from wastewater. The electrode material then undergoes a regeneration process, including: The used carbon-coated iron-nickel composite material was placed in an appropriate amount of deionized water, separated after the first irradiation treatment, and then placed in a mixed solution of water and ethanol with a volume ratio of 1:2-1:

5. After the second irradiation treatment, it was transferred to a vacuum drying oven to dry, thus completing the regeneration. The irradiation sources for the first and second irradiation treatments include electron accelerators, 60 Co or 137 Cs; The doses for the first and second irradiation treatments were between 5 and 50 kGy.

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