MoS2 nitrogen-phosphorus co-doped carbon nanowire adsorption material, preparation method thereof and application thereof in uranium adsorption

Abstract

The invention discloses a nitrogen-phosphorus co-doped carbon nanowire adsorption material and a preparation method and application thereof in uranium adsorption, and belongs to the field of radioactive wastewater treatment and environmental functional materials, the preparation method comprises the following steps: dissolving aniline and phytic acid in ionized water, and mixing to obtain a mixed solution; adding an ammonium persulfate aqueous solution into the mixed solution to obtain a phytic acid-polyaniline hybrid; washing the phytic acid-polyaniline hybrid to obtain a wet phytic acid-polyaniline hybrid; drying the wet phytic acid-polyaniline hybrid to obtain a phytic acid-polyaniline hybrid dried body; carbonizing the phytic acid-polyaniline hybrid dry body at a high temperature, and cooling to obtain the nitrogen and phosphorus co-doped carbon nanowire; dispersing a molybdenum source, a sulfur source and the nitrogen and phosphorus co-doped carbon nanowire in deionized water, and performing ultrasonic treatment to obtain a carbon nanowire precursor; and carrying out hydrothermal reaction on the carbon nanowire precursor, cooling, separating, washing and carrying out vacuum drying to obtain the carbon nanowire. The nitrogen and phosphorus co-doped carbon nanowire adsorption material disclosed by the invention has excellent adsorption capacity on uranium.

Description

Technical Field

[0001] This invention relates to the field of radioactive wastewater treatment and environmental functional materials technology, specifically to... Nitrogen-phosphorus co-doped carbon nanowire adsorbent materials, their preparation methods, and their application in uranium adsorption. Background Technology

[0002] With the rapid development of the nuclear energy industry, the direct discharge of radioactive wastewater generated during uranium mining, nuclear fuel processing, and nuclear facility decommissioning without effective treatment poses a serious threat to the ecological environment and human health. Uranium, as a key pollutant in radioactive wastewater, requires efficient and selective separation and recovery, which is one of the core requirements for nuclear environmental governance.

[0003] Currently, uranium adsorption technology has become one of the mainstream technologies for radioactive wastewater treatment due to its advantages such as simple operation, low cost, and environmental friendliness. Commonly used adsorption materials include activated carbon and metal-organic frameworks (MOFs). ), graphene oxide, metal sulfides, etc. Among them, molybdenum disulfide ( Because its surface is rich in sulfur (S) active sites, it can interact with S through... The strong coordination effect enables the efficient adsorption of uranium, and Its layered structure provides ample adsorption channels, resulting in a theoretically high adsorption capacity. However, a simple... The material suffers from problems such as easy agglomeration, poor dispersion in aqueous phase, and insufficient mechanical stability, resulting in an actual adsorption capacity that is far lower than the theoretical value. In addition, its recycling performance is poor, which limits its industrial application.

[0004] Carbon nanowires (CNWs), as one-dimensional carbon-based materials, possess high specific surface area, excellent electrical conductivity and mechanical stability, good aqueous dispersibility, and are easily functionalized, making them ideal carrier materials. In existing technologies, carbon nanowires are often used to load active components such as metal oxides and sulfides to improve their dispersibility; however, how to achieve… In situ uniform growth of carbon nanowires, suppression of aggregation and maximization of exposure of S active sites, while simplifying the preparation process and reducing costs, remain technical challenges that urgently need to be addressed. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides... Nitrogen-phosphorus co-doped carbon nanowire adsorbent materials, their preparation methods, and their applications in uranium adsorption, overcoming existing limitations. Overcoming the shortcomings of traditional adsorbent materials, such as easy aggregation, low adsorption capacity, poor selectivity, and insufficient cycle stability, this method achieves [adsorption / conversion] through an "interfacial polymerization-pyrolysis-in-situ hydrothermal" strategy. By uniformly loading nitrogen and phosphorus co-doped carbon nanowires and utilizing the carrier effect of carbon nanowires to improve the dispersibility and stability of the material, an adsorbent material with high adsorption capacity, high selectivity and excellent cycling performance for uranium is finally obtained.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A sort of A method for preparing nitrogen-phosphorus co-doped carbon nanowire adsorbent materials includes the following steps:

[0010] S1: Raw material mixing: Dissolve aniline and phytic acid in deionized water and mix them evenly with magnetic stirring at room temperature for 0.5-2 hours to obtain a mixed solution;

[0011] S2: Interfacial polymerization reaction: Add 0.2~1.0 mol / L of ammonium persulfate aqueous solution to the mixed solution in step S1, and let it stand at room temperature for 12~36 h to obtain phytic acid-polyaniline hybrid;

[0012] S3: Purification treatment: Wash the phytic acid-polyaniline hybrid with deionized water by centrifugation 3 to 5 times to obtain wet phytic acid-polyaniline hybrid;

[0013] S4: Drying treatment: Place the wet phytic acid-polyaniline hybrid in a vacuum drying oven at 80~120℃ and dry for 2~2 hours to obtain the dried phytic acid-polyaniline hybrid body;

[0014] S5: High-temperature carbonization: The dried phytic acid-polyaniline hybrid body is placed in a tube furnace, and... Under an inert atmosphere, carbonization was carried out at a high temperature of 850℃ and then naturally cooled to room temperature to obtain nitrogen-phosphorus co-doped carbon nanowires.

[0015] S6: Hydrothermal reaction: The molybdenum source, sulfur source, and the nitrogen-phosphorus co-doped carbon nanowires obtained above are dispersed in deionized water and ultrasonically stirred to obtain... Carbon nanowire precursor;

[0016] S7: Will The carbon nanowire precursor was transferred to a reaction vessel and hydrothermally reacted at 120–180 °C for 8–24 h. After cooling to room temperature, it was centrifuged and washed 3–5 times successively with deionized water and ethanol. The precursor was then vacuum dried at 600–900 °C to obtain the final product. Carbon nanowire adsorbent material, sealed and stored for later use.

[0017] Furthermore, in step S1, the molar ratio of aniline to phytic acid is 0.02 to 0.2.

[0018] Furthermore, in step S2, the volume ratio of the ammonium persulfate aqueous solution to the mixed solution is 0.5-1.0.

[0019] Furthermore, the molybdenum source is ammonium molybdate or sodium molybdate, and the sulfur source is thiourea.

[0020] Furthermore, the mass ratio of the molybdenum source: sulfur source: nitrogen and phosphorus co-doped carbon nanowires is 1:(1~5):1.

[0021] The nitrogen-phosphorus co-doped carbon nanowire adsorbent material was prepared using the method described above.

[0022] One as described above Preparation method of nitrogen and phosphorus co-doped carbon nanowire adsorbent materials Application of nitrogen-phosphorus co-doped carbon nanowire adsorbent materials in uranium adsorption.

[0023] Furthermore, the aforementioned The nitrogen-phosphorus co-doped carbon nanowire adsorbent material exhibits an adsorption selectivity of ≥86% for uranium in wastewater.

[0024] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0025] 1. The invention used In nitrogen-phosphorus co-doped carbon nanowire adsorbent materials, carbon nanowires serve as a carrier and can effectively inhibit... The aggregation of nanosheets maximizes the exposure of S active sites. S-sites on the surface and Strong coordination is formed, and the high specific surface area of ​​carbon nanowires provides ample adsorption channels, and the carbon nanowires and... The strong interfacial interaction (Mo-C bond) between the components prevents the active components from falling off, ensuring a high saturated adsorption capacity and removal rate for uranium.

[0026] 2. The invention used Nitrogen-phosphorus co-doped carbon nanowire adsorbents exhibit strong adsorption selectivity in uranium-containing wastewater: (The text abruptly ends here, likely due to an incomplete sentence or missing information.) , , , , , , or When ) is present, the material's adsorption selectivity for uranium remains ≥86%.

[0027] 3. The invention used The nitrogen-phosphorus co-doped carbon nanowire adsorption material has a simple preparation process, adopts an "interface polymerization-pyrolysis conversion-in-situ hydrothermal" strategy, does not need complex equipment, has mild reaction conditions, and is easy to scale up.

[0028] 4、 The raw material used in the method described in the application is simple and easy to obtain, and the end product is uranium, which is conducive to realizing the sustainability of resource-environment integration and recycling. BRIEF DESCRIPTION OF DRAWINGS

[0029] FIG. 1 is a SEM image of the nitrogen-phosphorus co-doped carbon nanowire adsorption material obtained in Example 1. Figure 1 FIG. 2 is a relationship between the adsorption effect of the adsorbent material obtained in Example 2 on uranium and the pH of the system.

[0030] Figure 2 FIG. 3 is a relationship between the adsorption effect of the adsorbent material obtained in Example 3 on uranium and the adsorption time of the system.

[0031] FIG. 4 is the effect of the adsorbent material obtained in Example 4 on uranium and the stability of the adsorbent. Figure 3 FIG. 5 is the influence of the adsorbent material on the adsorption selectivity of uranium when coexisting ions (Na+, K+, Ca2+, Mg2+, NH4+, Cl-, SO42-, HCO3-) exist.

[0032] Figure 4 FIG. 6 is a specific embodiment of the application.

[0033] FIG. 7 is a specific embodiment of the application. Figure 5 FIG. 8 is a specific embodiment of the application. , , , , , , or ) exist, the influence of the adsorbent material on the adsorption selectivity of uranium. DETAILED DESCRIPTION

[0034] The technical solutions in the application will be described below in conjunction with the embodiments in the application, and obviously, the described embodiments are only a part of the embodiments of the 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 application of the application or use. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0035] Example 1

[0036] A The preparation method of the nitrogen-phosphorus co-doped carbon nanowire adsorption material comprises the following steps:

[0037] ​​S1: Raw material mixing: Aniline and phytic acid are dissolved in deionized water at a molar ratio of 0.1:1 and mixed evenly by magnetic stirring at room temperature for 1 hour to obtain a mixed solution;

[0038] S2: Interfacial polymerization reaction: Add 0.8 mol / L ammonium persulfate aqueous solution to the mixed solution in step S1, and let it stand at room temperature for 24 h to obtain phytic acid-polyaniline hybrid, wherein the volume ratio of ammonium persulfate aqueous solution to mixed solution is 0.5:1;

[0039] S3: Purification treatment: The phytic acid-polyaniline hybrid was washed 5 times by centrifugation with deionized water to remove unreacted aniline, APS and oligomers, to obtain wet phytic acid-polyaniline hybrid;

[0040] S4: Drying treatment: The wet phytic acid-polyaniline hybrid was placed in a vacuum drying oven at 90℃ and dried for 8 hours to obtain the dried phytic acid-polyaniline hybrid body;

[0041] S5: High-temperature carbonization: The dried phytic acid-polyaniline hybrid body is placed in a tube furnace, and... Under an inert atmosphere, carbonization was carried out at a high temperature of 850℃ and then naturally cooled to room temperature to obtain nitrogen-phosphorus co-doped carbon nanowires.

[0042] S6: Hydrothermal reaction: The molybdenum source, sulfur source, and the nitrogen-phosphorus co-doped carbon nanowires obtained above are dispersed in deionized water and ultrasonically stirred to obtain... The carbon nanowire precursor is ammonium molybdate as the molybdenum source and thiourea as the sulfur source. The mass ratio of molybdenum source: sulfur source: nitrogen and phosphorus co-doped carbon nanowires is 1:2.5:1.

[0043] S7: Will The carbon nanowire precursor was transferred to a reaction vessel and hydrothermally reacted at 150°C for 12 h. After cooling to room temperature, it was centrifuged, washed five times successively with deionized water and ethanol, and then vacuum dried at 750°C to obtain the desired product. Carbon nanowire adsorbent material, sealed and stored for later use.

[0044] Example 2

[0045] pH The effect of nitrogen-phosphorus co-doped carbon nanowire adsorbents on uranium adsorption.

[0046] The uranium solution was injected into a 500 mL Erlenmeyer flask, and the uranium mass concentration was 50 mg·L⁻¹. -1 Subsequently, through 0.1 mol·L -1 Nitric acid and 0.1 mol·L -1 The pH value was adjusted using sodium hydroxide solution to maintain the system's pH within the range of 2-7. Finally, 15 mg of sodium hydroxide solution was added. N, P-codoped carbon nanowires, adsorption time is 24 h, adsorption temperature is 25℃; after the reaction, centrifugal, remove 1 mL supernatant, use visible spectrophotometry to determine the content of uranium in solution, calculate the adsorption rate and adsorption capacity. Figure 2 As shown in FIG. (2), when the pH value is 6, The adsorption capacity of N, P-codoped carbon nanowires adsorbent adsorbent to uranium in solution is also optimal 379.38 mg·g-1( Figure 2 (a)), and the adsorption rate is maximum 94.84% ( Figure 2 (b)).

[0047] Example 3

[0048] The effect of adsorption time on N, P-codoped carbon nanowires adsorbent adsorbent to uranium.

[0049] The uranium solution is injected into a conical flask with a volume of 500 mL, and the mass concentration of uranium is 50 mg·L -1 , then 0.1 mol·L -1 of sodium hydroxide concentrated solution is used to adjust the pH value, so that the pH value of the system is 6, and finally 15 mg N, P-codoped carbon nanowires are added, and the temperature is 25 o C, and the adsorption time is 1-240 min; after the reaction, centrifugal, remove 1 mL supernatant, use visible spectrophotometry to determine the content of uranium in solution, calculate the adsorption rate and adsorption capacity. As shown in FIG. (3), when the reaction time is ≥120 min, the adsorption of uranium in wastewater begins to approach saturation, and almost all of it is adsorbed.

[0050] Example 4

[0051] The adsorption stability of N, P-codoped carbon nanowires adsorbent adsorbent to uranium.

[0052] The uranium solution is injected into a conical flask with a volume of 500 mL, and the mass concentration of uranium is 50 mg·L -1 , then 0.1 mol·L -1 of sodium hydroxide concentrated solution is used to adjust the pH value, so that the pH value of the system is 6, and finally 15 mg N, P-codoped porous carbon adsorbent is added, and the temperature is 25 o C, and the adsorption time is 24 h; after the reaction, centrifugal, remove 1 mL supernatant, use visible spectrophotometry to determine the content of uranium in solution, calculate the adsorption rate and adsorption capacity. The filter residue is washed, dried and reused 1-4 times. As shown in FIG. (4), when After the N, P-codoped carbon nanowires adsorbent is reused 5 times, the removal rate of uranium in wastewater still remains as high as 89.8%.

[0053] Example 5

[0054] In coexisting ions ( , , , , , , or When they exist separately, The effect of nitrogen-phosphorus co-doped carbon nanowires on the adsorption selectivity of uranium.

[0055] Prepare uranium-containing and coexisting ions separately ( , , , , , , or The mixture of the two solutions was then injected into a 500 mL Erlenmeyer flask, and the solution was reacted with 0.1 mol·L⁻¹. -1 The pH of the system was adjusted to 6 using concentrated sodium hydroxide solution, and finally 5 mg of sodium hydroxide solution was added. Nitrogen-phosphorus co-doped carbon nanowire adsorbent material, at a temperature of 25°C. o C, the adsorption time is 300 min; after the reaction is completed, centrifuge, transfer 1 mL of the supernatant, and determine the uranium content in the solution by visible spectrophotometry, and calculate the adsorption rate and adsorption amount. As shown in Figure (5), in the presence of a certain coexisting ion, the adsorption selectivity of the adsorbent material for uranium still remains ≥86%, and selective separation of uranium can be achieved.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing nitrogen-phosphorus co-doped carbon nanowire adsorbent materials, characterized in that: Includes the following steps: S1: Raw material mixing: Dissolve aniline and phytic acid in deionized water and mix them evenly with magnetic stirring at room temperature for 0.5-2 hours to obtain a mixed solution; S2: Interfacial polymerization reaction: Add 0.2~1.0 mol / L of ammonium persulfate aqueous solution to the mixed solution in step S1, and let it stand at room temperature for 12~36 h to obtain phytic acid-polyaniline hybrid; S3: Purification treatment: Wash the phytic acid-polyaniline hybrid with deionized water by centrifugation 3 to 5 times to obtain wet phytic acid-polyaniline hybrid; S4: Drying treatment: Place the wet phytic acid-polyaniline hybrid in a vacuum drying oven at 80~120℃ and dry for 2~2 hours to obtain the dried phytic acid-polyaniline hybrid body; S5: High-temperature carbonization: The dried phytic acid-polyaniline hybrid body is placed in a tube furnace, and... Under an inert atmosphere, carbonization was carried out at a high temperature of 850℃ and then naturally cooled to room temperature to obtain nitrogen-phosphorus co-doped carbon nanowires. S6: Hydrothermal reaction: The molybdenum source, sulfur source, and the nitrogen-phosphorus co-doped carbon nanowires obtained above are dispersed in deionized water and ultrasonically stirred to obtain... Carbon nanowire precursor; S7: Will The carbon nanowire precursor was transferred to a reaction vessel and hydrothermally reacted at 120–180 °C for 8–24 h. After cooling to room temperature, it was centrifuged and washed 3–5 times successively with deionized water and ethanol. The precursor was then vacuum dried at 600–900 °C to obtain the final product. Carbon nanowire adsorption materials.

2. As described in claim 1 A method for preparing nitrogen-phosphorus co-doped carbon nanowire adsorbent materials, characterized in that: In step S1, the molar ratio of aniline to phytic acid is 0.02 to 0.

2.

3. As described in claim 1 A method for preparing nitrogen-phosphorus co-doped carbon nanowire adsorbent materials, characterized in that: In step S2, the volume ratio of ammonium persulfate aqueous solution to the mixed solution is 0.5~1.

0.

4. As described in claim 1 A method for preparing nitrogen-phosphorus co-doped carbon nanowire adsorbent materials, characterized in that: The molybdenum source is ammonium molybdate or sodium molybdate, and the sulfur source is thiourea.

5. The method according to claim 1 A method for preparing nitrogen-phosphorus co-doped carbon nanowire adsorbent materials, characterized in that: The mass ratio of the molybdenum source, sulfur source, and nitrogen-phosphorus co-doped carbon nanowires is 1:(1~5):

1.

6. A preparation method according to any one of claims 1 to 5. Nitrogen-phosphorus co-doped carbon nanowire adsorbent materials.

7. A device as described in claim 6 The application of nitrogen-phosphorus co-doped carbon nanowire adsorbent materials in uranium adsorption is characterized by: The The adsorption selectivity of nitrogen-phosphorus co-doped carbon nanowire adsorbent for uranium in wastewater is ≥86%.

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