Preparation method and application of controllably synthesized zero-valent nickel ZnCdS composite material

Abstract

The invention discloses a preparation method and application of a controllably synthesized zero-valent nickel ZnCdS composite material, and particularly relates to the field of adsorption materials. The preparation method comprises the following steps: adding ethylenediamine into precursors of zinc and cadmium and a sulfur source, preserving heat at 80-160 DEG C for 10-16 hours, and centrifuging to obtain the ZnCdS nanosheet. The preparation method comprises the following steps: dissolving ZnCdS and a precursor of nickel in deionized water to obtain a solution A; dissolving sodium borohydride in deionized water, and stirring to form a sodium borohydride solution, so as to obtain a solution B; and adding the solution B into the solution A, stirring for 6-24 hours, centrifuging, cleaning the precipitate with deionized water, quickly transferring a sample into a deep freezing chamber, freezing for 4-15 hours, transferring into a freeze dryer, and drying for 8-24 hours, thereby obtaining the zero-valent nickel / ZnCdS composite material. According to the technical scheme, the method is simple, the cost is low, reaction conditions are easy to control, and the prepared adsorbent solves the problem that adsorption of uranium is seriously limited due to serious agglomeration of zero-valent nickel and insufficient active sites, and has wide application prospects in the field of extraction of uranium from seawater.

Description

TECHNICAL FIELD

[0001] The application relates to the field of adsorption materials, and particularly relates to a preparation method and application of controllably synthesized zero-valent nickel ZnCdS composite materials. BACKGROUND

[0002] In recent years, due to the urgent demand for clean energy, nuclear energy with the advantages of high energy density and low carbon emission has attracted extensive attention. At present, uranium is the fuel for providing power for nuclear power plants and producing nuclear energy. However, the limited land uranium resources seriously restrict the sustainable development of nuclear power, and in contrast, the ocean uranium reserves are thousands of times higher than the land uranium reserves. In addition, traditional uranium mining will produce tailings pollution, which seriously damages the ecological environment, while seawater uranium extraction will not harm the ecological environment and has lower pollution risk. Therefore, it is of practical significance to collect uranium on a large scale from seawater. So far, a variety of seawater uranium extraction technologies have been developed, such as adsorption method, biological enrichment method, membrane separation method, electrochemical method, photocatalytic method and the like. Among all the seawater uranium extraction technologies, the adsorption method becomes a feasible technology for seawater uranium extraction due to its simple operation, low energy consumption, economy and environmental friendliness and the like. Zhang et al. constructed a micro-aerobic redox reactor for Cu(I) / Cu(II) conversion, induced the activation and regeneration of inactivated binding sites, and improved the capture capacity of the adsorbent for uranium, so that the adsorbent has a high adsorption capacity (962.40 mg-U / g-Ads) (Nature Communications (2024) 15:9124).

[0003] The key of the adsorption method lies in the development of an adsorbent which can adapt to the marine environment, has selectivity, low operation cost and good resistance to pollution. Up to now, a variety of adsorbents have been used for seawater uranium extraction. For example: Zhang et al. synthesized mussel-type magnetic activated carbon, and the uranium recovery rate in the simulated seawater is 427.7 μg / g (Journal of Colloid and Interface Science 534 (2019) 172-182); the extraction performance of the supramolecular supported poly-gem amine oxime macroporous resin synthesized by Wen et al. is 157 mg / g in seawater containing 32 ppm (ACS Appl. Mater. Interfaces 2021, 13, 3246-3258); the uranium extraction performance of the ground crab shell realized by Feng et al. is 1.38 mg / g in natural seawater (Chemical Engineering Journal 430 (2022) 133038). As a typical zero-valent metal, zero-valent nickel has excellent adsorption performance and reduction activity, so it has strong application potential in the field of seawater uranium extraction. However, the zero-valent nickel particles are easy to agglomerate and oxidize in practical application, which seriously limits the adsorption capacity. Summary of the Invention

[0004] The present invention aims to provide a preparation method and application of a controllably synthesized zero-valent nickel ZnCdS composite material, which solves the problem that the shortcomings of easy agglomeration and insufficient active sites of zero-valent nickel seriously limit its adsorption of uranium.

[0005] In order to achieve the above object, the present invention provides a technical solution as follows: a method for preparing a controllably synthesized zero-valent nickel ZnCdS composite material, comprising the following steps: S1. Add a zinc precursor, a cadmium precursor, and a sulfur source to a reaction vessel, and add 50-90 mL of a solvent to the reaction vessel, stir and heat to 100-140° C., keep warm for 10-16 hours, and then naturally cool to room temperature; S2. Centrifuge the product of step S1, wash the precipitate with deionized water, and vacuum dry it at 40-80° C. for 6-12 hours to obtain ZnCdS nanosheets; S3. Add an appropriate amount of nickel precursor and ZnCdS into a reaction vessel, add 30-60 mL of deionized water into the vessel, and stir for 0.5-3 h under an inert gas atmosphere; S4. Add 0.5g-2g of sodium borohydride to 30-60mL of deionized water and continue stirring for 1-4h until the solution no longer produces bubbles; S5, adding the sodium borohydride solution of step S4 to the mixed solution of step S3, and stirring under inert gas protection for 10-24 hours; S6. Centrifuge the mixed solution of step S5, wash the precipitate with deionized water, freeze the sample for 4-15 hours, and then transfer it to a freeze dryer and dry it for 8-24 hours to obtain a zero-valent nickel / ZnCdS composite material.

[0006] Furthermore, in step S1, the molar ratio of the zinc precursor, the cadmium precursor, and the sulfur source is 1:1:2.

[0007] Through the above setting, the adsorbent prepared by adopting this ratio has a stable structure and a high number of active sites.

[0008] Furthermore, in step S1, the zinc precursor is selected from zinc acetate, zinc chloride, and zinc nitrate; the cadmium precursor is selected from cadmium acetate, cadmium chloride, and cadmium sulfate; and the sulfur source is selected from thiourea or thioacetamide.

[0009] Furthermore, the solvent in step S1 is ethylenediamine, diethylenetriamine or triethylenetetramine.

[0010] Through the above setting, the solvent can not only effectively dissolve and stabilize the metal precursor, but also play an important role in template and crystal regulation when synthesizing nanomaterials, and has the characteristics of environmental friendliness and degradability, which makes it have potential in green chemistry and environmentally friendly synthesis.

[0011] Further, the inert gas in steps S3 and S5 is nitrogen or argon.

[0012] Through the above setting, the inert gas helps to prevent product oxidation, improve product yield, maintain stable reaction conditions and ensure the safety and stability of the reaction process.

[0013] Further, the reaction vessel in step S1 is a Teflon reaction kettle.

[0014] Through the above setting, the Teflon reaction kettle has the advantages of high sealing property, high safety, economy and easy maintenance.

[0015] Further, the reaction vessel in step S3 is a three-necked flask or a four-necked flask.

[0016] Further, the incorporation amount of zero-valent nickel is 1.5 mmol, and a 2-zero-valent nickel / ZnCdS composite material is prepared.

[0017] Another technical solution provided by the present application is that the controllable synthesized zero-valent nickel ZnCdS composite material is used in the seawater uranium extraction process.

[0018] Compared with the prior art, the present application has the following advantages: 1、In the present application, the ZnCdS nanosheet not only has the advantages of two-dimensional material, but also has excellent hydrophilicity and stability. 2- As a soft Lewis base, it can form strong interaction with soft Lewis acid UO2 2+ , achieve the purpose of adsorbing uranium. 2- Can store electrons for the reduction of UO2 2+ , also can be used as electron donor to accelerate electron transfer, promote the reduction of UO2 2+ . Adjusting the loading amount of zero-valent nickel on the ZnCdS nanosheet can obtain ZnCdS nanosheet with optimal adsorption performance.

[0019] 2、The preparation method provided by the present application has the advantages of simple preparation method, easy operation, wide source of raw materials, easy control of reaction conditions, etc. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the XRD pattern of the zero-valent nickel / ZnCdS composite material prepared in Example 1-3; Figure 2 is a transmission electron micrograph of 2-zerovalent nickel / ZnCdS prepared in Example 2; Figure 3 is the infrared (FT-IR) spectrum of uranium adsorbed on 2-zerovalent nickel / ZnCdS prepared in Example 2; Figure 4 This is a graph showing the uranium adsorption performance of 2-zerovalent nickel / ZnCdS prepared in Example 2 in real seawater. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below through specific embodiments: Example

[0022] A method for preparing a controllably synthesized zero-valent nickel (ZnCdS) composite material comprises the following steps: ultrasonically dispersing 1.5 mmol of zinc nitrate dihydrate, 1.5 mmol of cadmium chloride dihydrate, and 3 mmol of thioacetamide in 50 mL of diethylenetriamine solution. The solution is then stirred until uniformly dispersed, transferred to a 100 mL Teflon reactor, and maintained at 100°C for 11 hours. After the reaction, the solution is cooled to room temperature. The resulting mixture is then washed three times with deionized water and anhydrous ethanol in a 1:1 volume ratio. Finally, the mixture is vacuum-dried at 60°C for 8 hours to obtain ZnCdS ultrathin nanosheets.

[0023] Weigh 50 mg of ZnCdS and add it to a three-necked flask with 50 mL of deionized water. The volume of the three-necked flask is 100 mL, and stir at a rate of 700 rpm / min for 5 minutes to form a uniformly dispersed suspension. Then add 0.5 mmol of nickel acetate and stir the mixed solution for 2 hours. At the same time, disperse 0.5 g of sodium borohydride (NaBH4) in 50 mL of deionized water, and then add the sodium borohydride solution dropwise to the above solution and stir for 12 hours under an argon atmosphere. After the reaction is completed, use a centrifuge to obtain the precipitate, and wash the precipitate several times with deionized water. The sample is quickly transferred to a refrigerator and frozen for 8 hours to freeze the water in the sample into a solid state. It is then dried in a freeze dryer for 12 hours, and the water is removed by sublimation under vacuum conditions to obtain a 1-zero-valent nickel / ZnCdS composite material (such as Figure 1 As shown, the horizontal axis is the 2θ diffraction angle and the vertical axis is the diffraction intensity).

[0024] The evaluation method for the adsorption performance of zero-valent nickel / ZnCdS on uranium in seawater is as follows: 10 mg of the adsorbent was dispersed in 100 mL of seawater containing 50 mg / L of uranium. The pH of the U(VI) solution was adjusted between 3 and 8 using 0.05 M HCl and NaOH solutions. Adsorption experiments were conducted at room temperature with stirring. After one hour of adsorption, 1.5-3.5 mL of the solution was collected and filtered to remove the adsorbent. The uranium ion concentration was then measured using an inductively coupled plasma spectrometer (ICP). Figure 1 The X-ray diffraction pattern of zero-valent nickel / ZnCdS is shown. According to the spectrum, the prepared 1-zero-valent nickel / ZnCdS has good crystallinity, and the XRD diffraction peaks can be compared with those corresponding to Zn 0.5 Cd 0.5 The characteristic diffraction peaks of S (PDF#89-2943) and Ni (PDF#04-0850) are well matched. Example

[0025] A method for preparing a controllably synthesized zero-valent nickel (ZnCdS) composite material comprises the following steps: ultrasonically dispersing 1.5 mmol of zinc acetate dihydrate, 1.5 mmol of cadmium acetate dihydrate, and 3 mmol of thiourea in 70 mL of ethylenediamine solution. The solution is then stirred until uniformly dispersed, transferred to a 100 mL Teflon reactor, and maintained at 100°C for 11 hours. After the reaction, the solution is cooled to room temperature. The resulting mixture is then washed three times with deionized water and anhydrous ethanol in a 1:1 volume ratio. Finally, the mixture is vacuum-dried at 60°C for 8 hours to obtain ZnCdS ultrathin nanosheets.

[0026] Weigh 50 mg of ZnCdS and add it to a three-necked flask with 50 mL of deionized water. The volume of the three-necked flask is 100 mL, and stir at a rate of 700 rpm / min for 5 minutes to form a uniformly dispersed suspension. Then add 1.5 mmol of nickel acetate and stir the mixed solution for 2 hours. At the same time, disperse 1.0 g of sodium borohydride (NaBH4) in 50 mL of deionized water, and then add the sodium borohydride solution dropwise to the above solution and stir for 12 hours under an argon atmosphere. After the reaction is completed, use a centrifuge to obtain the precipitate, and wash the precipitate several times with deionized water. The sample is then quickly transferred to a refrigerator and frozen for 8 hours to freeze the water in the sample into a solid state. It is then dried in a freeze dryer for 12 hours, and the water is removed by sublimation under vacuum conditions to obtain a 2-zero-valent nickel / ZnCdS composite material (such as Figure 1 As shown, the horizontal axis is the 2θ diffraction angle and the vertical axis is the diffraction intensity).

[0027] The evaluation method for the adsorption performance of zero-valent nickel / ZnCdS on uranium in seawater is as follows: 10 mg of the adsorbent was dispersed in 100 mL of seawater containing 50 mg / L of uranium. The pH of the U(VI) solution was adjusted within a range of 3-8 using 0.05 M HCl and NaOH solutions. Adsorption experiments were conducted at room temperature with stirring. After one hour of adsorption, 1.5-3.5 mL of the solution was collected and filtered to remove the adsorbent. The uranium ion concentration was measured using an inductively coupled plasma spectrometer (ICP). The adsorption capacity of the adsorbent for uranium was calculated using the adsorption capacity formula. Figure 1 The X-ray diffraction pattern of zero-valent nickel / ZnCdS is shown. According to the spectrum, the prepared 2-zero-valent nickel / ZnCdS has good crystallinity, and the XRD diffraction peaks can be compared with those corresponding to Zn 0.5 Cd 0.5 The characteristic diffraction peaks of S (PDF#89-2943) and Ni (PDF#04-0850) are well matched. Figure 2 The transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) images of 2-zerovalent nickel / ZnCdS are shown. Figure 2 The transmission image shows that the prepared zerovalent nickel nanoparticles are well dispersed on the ZnCdS nanosheets. Figure 3 The FTIR after adsorption of U(VI) is shown, 887 cm -1 The peak at is O=U=O, indicating that uranium is adsorbed on the material. Figure 4 (a) shows the adsorption capacity of uranium under different pH conditions in seawater. When C0=50 mg / L, the adsorption capacity of uranium ions at pH 4-8 is excellent. Among them, the adsorption performance of uranium is the best (90%) when pH=4. Therefore, pH=4 is selected to test the effect of different initial uranium concentrations (C0) in seawater on uranium adsorption capacity, as shown in the figure below. Figure 4 As shown in (b): When C0 = 10, 30, 50, 80, 100 mg / L, the adsorption performance of uranium can reach more than 80%. Example

[0028] A method for preparing a controllably synthesized zero-valent nickel (ZnCdS) composite material comprises the following steps: ultrasonically dispersing 3 mmol of zinc acetate dihydrate, 3 mmol of cadmium acetate dihydrate, and 6 mmol of thiourea in 90 mL of ethylenediamine solution. The solution is then stirred until uniformly dispersed, transferred to a 100 mL Teflon reactor, and maintained at 120°C for 10 hours. After the reaction, the solution is cooled to room temperature. The resulting mixture is then washed three times with deionized water and anhydrous ethanol in a 1:1 volume ratio. Finally, the mixture is vacuum-dried at 60°C for 8 hours to obtain ZnCdS ultrathin nanosheets.

[0029] Weigh 50 mg of ZnCdS and add it to a three-necked flask with 6 mL of deionized water. The volume of the three-necked flask is 100 mL, and stir at a rate of 700 rpm / min for 5 minutes to form a uniformly dispersed suspension. Then add 3 mmol of nickel acetate and stir the mixed solution for 2 hours. At the same time, disperse 1.5 g of sodium borohydride (NaBH4) in 50 mL of deionized water, and then add the sodium borohydride solution dropwise to the above solution and stir for 12 hours under an argon atmosphere. After the reaction is completed, use a centrifuge to obtain the precipitate, and wash the precipitate several times with deionized water. The sample is then quickly transferred to a refrigerator and frozen for 6 hours to freeze the water in the sample into a solid state. It is then dried in a freeze dryer for 10 hours, and the water is removed by sublimation under vacuum conditions to obtain a 3-zero-valent nickel / ZnCdS composite material (such as Figure 1 As shown, the horizontal axis is the 2θ diffraction angle and the vertical axis is the diffraction intensity).

[0030] The evaluation method for the adsorption performance of zero-valent nickel / ZnCdS on uranium in seawater is as follows: 10 mg of the adsorbent was dispersed in 100 mL of seawater containing 50 mg / L of uranium. The pH of the U(VI) solution was adjusted between 3 and 8 using 0.05 M HCl and NaOH solutions. Adsorption experiments were conducted at room temperature with stirring. After one hour of adsorption, 1.5-3.5 mL of the solution was collected and filtered to remove the adsorbent. The uranium ion concentration was measured using an inductively coupled plasma spectrometer (ICP). The adsorption capacity of the adsorbent for uranium was calculated using the adsorption capacity formula. Figure 1 The X-ray diffraction pattern of zero-valent nickel / ZnCdS is shown. According to the spectrum, the prepared 3-zero-valent nickel / ZnCdS has good crystallinity, and the XRD diffraction peaks can be compared with those corresponding to Zn 0.5 Cd 0.5 The characteristic diffraction peaks of S (PDF#89-2943) and Ni (PDF#04-0850) are well matched. Example

[0031] A method for preparing a controllably synthesized zero-valent nickel (ZnCdS) composite material comprises the following steps: ultrasonically dispersing 1.5 mmol of zinc chloride dihydrate, 1.5 mmol of cadmium sulfate dihydrate, and 3 mmol of thiourea in 70 mL of triethylenetetramine solution. The solution is then stirred until uniformly dispersed, transferred to a 100 mL Teflon reactor, and maintained at 140°C for 16 hours. After the reaction, the solution is cooled to room temperature and then washed three times with deionized water and anhydrous ethanol in a 1:1 volume ratio. Finally, the resulting ZnCdS ultrathin nanosheets are dried in a vacuum at 40°C for 12 hours.

[0032] 50 mg of ZnCdS was weighed and added to a 100 mL four-necked flask containing 30 mL of deionized water. The flask was stirred at 700 rpm / min for 5 minutes to form a uniformly dispersed suspension. 0.5 mmol of nickel acetate was then added, and the mixture was stirred for 4 hours. Simultaneously, 2.0 g of sodium borohydride (NaBH4) was dispersed in 50 mL of deionized water. The NaBH4 solution was then added dropwise to the mixture, and the mixture was stirred under a nitrogen atmosphere for 24 hours. After the reaction was complete, the precipitate was collected using a centrifuge and washed several times with deionized water. The sample was then quickly transferred to a freezer and frozen for 15 hours to solidify the water in the sample. It was then dried in a freeze dryer for 15 hours to remove the water by sublimation under vacuum conditions, yielding a zero-valent nickel / ZnCdS composite.

[0033] The evaluation method for the adsorption performance of zero-valent nickel / ZnCdS on uranium in seawater is as follows: 10 mg of the adsorbent was dispersed in 100 mL of seawater containing 50 mg / L of uranium. The pH of the U(VI) solution was adjusted in the range of 3-8 using 0.05 M HCl and NaOH solutions. Adsorption experiments were performed at room temperature with stirring. After one hour of adsorption, 1.5-3.5 ml of the solution was collected and the adsorbent was filtered out. The uranium ion concentration was then measured using an inductively coupled plasma spectrometer (ICP).

[0034] The above are only embodiments of the present invention, and common knowledge such as the specific structure and / or characteristics of the scheme are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a controllable synthesis of zero-valent nickel ZnCdS composite material, characterized in that: The steps include: S1. Add a zinc precursor, a cadmium precursor, and a sulfur source to a reaction vessel, and add 50-90 mL of a solvent to the reaction vessel, stir and heat to 100-140° C., keep warm for 10-16 hours, and then naturally cool to room temperature; S2, centrifuging the product of step S1, washing the precipitate with deionized water, and vacuum drying at 40-60° C. for 8-12 hours to obtain ZnCdS nanosheets; S3. Add an appropriate amount of nickel precursor and ZnCdS into a reaction vessel, add 30-60 mL of deionized water into the vessel, and stir for 0.5-3 h under an inert gas atmosphere; S4. Add 0.5g-2g of sodium borohydride to 30-60mL of deionized water and continue stirring for 1-4h until the solution no longer produces bubbles; S5, adding the sodium borohydride solution of step S4 to the mixed solution of step S3, and stirring under inert gas protection for 12-24 hours; S6. Centrifuge the mixed solution of step S5, wash the precipitate with deionized water, freeze the sample for 4-15 hours, and then transfer it to a freeze dryer and dry it for 8-24 hours to obtain a zero-valent nickel / ZnCdS composite material.

2. The method for preparing a controllably synthesized zero-valent nickel ZnCdS composite material according to claim 1, wherein: In step S1 , the molar ratio of the zinc precursor, the cadmium precursor, and the sulfur source is 1:1:

2.

3. The method for preparing a controllably synthesized zero-valent nickel ZnCdS composite material according to claim 2, wherein: In step S1, the zinc precursor is selected from zinc acetate, zinc chloride, and zinc nitrate; the cadmium precursor is selected from cadmium acetate, cadmium chloride, and cadmium sulfate; and the sulfur source is selected from thiourea or thioacetamide.

4. The method for preparing a controllably synthesized zero-valent nickel ZnCdS composite material according to claim 1, wherein: The solvent in step S1 is ethylenediamine, diethylenetriamine or triethylenetetramine.

5. The method for preparing a controllably synthesized zero-valent nickel ZnCdS composite material according to claim 1, wherein: The inert gas in steps S3 and S5 is nitrogen or argon.

6. The method for preparing a controllably synthesized zero-valent nickel ZnCdS composite material according to claim 1, wherein: The reaction container in step S1 is a Teflon reactor.

7. The method for preparing a controllably synthesized zero-valent nickel ZnCdS composite material according to claim 1, wherein: The reaction container in step S3 is a three-necked flask or a four-necked flask.

8. The method for preparing a controllably synthesized zero-valent nickel ZnCdS composite material according to claim 1, wherein: The doping amount of zero-valent nickel was 1.5 mmol, and a 2-zero-valent nickel / ZnCdS composite material was prepared.

9. Using the controllably synthesized zero-valent nickel ZnCdS composite material according to claims 1-8 in a seawater uranium extraction process.

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