Antimony-containing nickel-based composite material as well as preparation method and application thereof

Abstract

The invention discloses an antimony-containing nickel-based composite material and a preparation method and application thereof.The antimony-containing nickel-based composite material comprises foamed nickel and an antimony-containing complex growing on the foamed nickel, and the antimony-containing complex comprises a NiSb phase and a Ni3S2 phase. According to the invention, a simple and convenient one-step solvothermal method is adopted, foamed nickel (NF) is used as a substrate and a nickel source, and the antimony-containing nickel-based composite material with efficient iodine adsorption performance is prepared by regulating and controlling the addition amount of an antimony (Sb) source.

Description

Technical Field

[0001] The present invention relates to the technical field of iodine adsorption, and in particular to an antimony-containing nickel-based composite material, a preparation method thereof and applications thereof. Background Art

[0002] Nuclear energy is one of the most promising energy sources for power generation. However, nuclear power plants produce a large amount of radioactive pollutants during operation, which poses great harm to the environment and humans. The management of nuclear waste has become a major safety issue in nuclear power production. Improper handling or disposal may lead to the following: 129 I and 131 The accidental release of radionuclides including I. Therefore, it is very necessary to develop efficient iodine adsorbents.

[0003] In the early work of this research group, sulfonated β-cyclodextrin was reacted with NO3-type nickel-aluminum layered hydroxide using ion exchange reaction to obtain sulfonated β-cyclodextrin-LDH complex. This complex is an organic-inorganic composite adsorbent material with good iodine adsorption performance and can be used as an elemental iodine adsorption material.

[0004] In order to further expand the types of iodine adsorbents, it is necessary to develop more iodine adsorption materials of different systems. Summary of the Invention

[0005] The first aspect of the present invention aims to provide a novel antimony-containing nickel-based composite material. The second aspect of the present invention aims to provide a method for preparing the antimony-containing nickel-based composite material. The third aspect of the present invention aims to provide the use of the antimony-containing nickel-based composite material as an iodine adsorbent.

[0006] To achieve the above objectives:

[0007] A first aspect of the present invention provides an antimony-containing nickel-based composite material, comprising:

[0008] Nickel foam, and

[0009] An antimony-containing composite body grown on the nickel foam comprises a NiSb phase and a Ni3S2 phase.

[0010] In some embodiments, the antimony-containing composite exhibits a spherical morphology.

[0011] In some embodiments, the antimony-containing composite is prepared by reacting an antimony source and a sulfur source in a molar ratio of 1:(0.21-0.65) with a stoichiometric excess of a nickel source.

[0012] In some embodiments, the antimony source is potassium pyroantimonate, the sulfur source is elemental sulfur, and / or the nickel source is nickel foam.

[0013] A second aspect of the present invention provides a method for preparing an antimony-containing nickel-based composite material, comprising:

[0014] An antimony source and a sulfur source in a molar ratio of 1:(0.21-0.65) are mixed with a stoichiometric excess of a nickel source and then subjected to a solvothermal reaction.

[0015] In some embodiments, the solvent for the solvothermal reaction is a mixed solvent of ethylene glycol and water. Preferably, the volume ratio of ethylene glycol to water is 20:8.

[0016] In some embodiments, the solvothermal reaction temperature is 160-200° C., and the reaction time is 6-12 hours.

[0017] In some embodiments, the antimony source is potassium pyroantimonate, the sulfur source is elemental sulfur, and / or the nickel source is nickel foam.

[0018] In some embodiments, the preparation method specifically comprises:

[0019] Dissolving potassium pyroantimonate, sulfur powder, and citric acid in a mixed solvent to obtain a mixed solution;

[0020] In the presence of hydrazine hydrate, the mixed solution is brought into contact with nickel foam and a solvothermal reaction is performed.

[0021] The third aspect of the present invention provides the use of the aforementioned antimony-containing nickel-based composite material as an iodine adsorbent.

[0022] Beneficial effects

[0023] The present invention adopts a simple one-step solvent thermal method, using nickel foam (NF) as substrate and nickel source, and by regulating the addition amount of antimony (Sb) source, prepares an antimony-containing nickel-based composite material with efficient iodine adsorption performance. Especially, when the Sb source addition amount is 1mmol, the obtained 1-NiSb / Ni3S2 / NF presents an optimal spherical morphology, provides more adsorption sites, and shows a high adsorption capacity (1786mg / g) to I2. Moreover, the antimony-containing nickel-based composite material provided by the present invention is an inorganic adsorbent, which can achieve more stable adsorption and solidification for elemental iodine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 XRD spectra of Ni3S2 / NF (a), 0.5-Ni3S2 / NF (b), 1-NiSb / Ni3S2 / NF (c) and 4-NiSb / NF (d) are shown respectively;

[0025] Figure 2 shows the SEM image of the NF substrate;

[0026] Figure 3SEM images of Ni3S2 / NF(aa”), 0.5-Ni3S2 / NF(bb”), 1-NiSb / Ni3S2 / NF(cc”) and 4-NiSb / NF(dd”) are shown;

[0027] Figure 4 The SEM image of 1-NiSb / Ni3S2 / NF and the element distribution of Sb, Ni, and S therein are shown;

[0028] Figure 5 The full XPS spectrum (a) and XPS spectra of Sb 3d (b), Ni 2p (c), and S2p (d) elements of 1-NiSb / Ni3S2 / NF are shown;

[0029] Figure 6 The maximum iodine adsorption capacity and the iodine adsorption capacity after desorption of different samples are shown;

[0030] Figure 7 The adsorption kinetics of 1-NiSb / Ni3S2 / NF are shown. DETAILED DESCRIPTION

[0031] Preparation Example of Antimony-Containing Nickel-Based Composite Material (Also Called NiSb / Ni3S2 / NF)

[0032] Treatment of NF

[0033] Each piece of NF with a size of 1 cm × 1 cm was treated with 1 M HCl to remove surface impurities, and then ultrasonically treated with acetone and deionized water until the pH of the solution was neutral, and finally placed in a vacuum oven to dry.

[0034] Example 1

[0035] An antimony-containing nickel-based composite material was prepared using a solvothermal method. Potassium pyroantimonate (1 mmol, 0.256 g) was placed in a mixture of ethylene glycol (20 ml) and water (8 ml). 0.65 mmol (0.021 g) of sulfur powder and 3 mmol (0.6 g) of citric acid were added and stirred continuously at 60°C for 40 minutes. The resulting mixture and 2 mL of hydrazine hydrate (80% N₂H₄·H₂O) were placed in a 50 mL polytetrafluoroethylene-lined stainless steel autoclave. Eight pretreated NF sheets (approximately 0.64 mol per sheet) with a 1 cm × 1 cm area were then added. The autoclave was sealed and placed in an electrically heated constant-temperature forced-air drying oven at 180°C for 8 hours. The mixture was then cooled to room temperature, washed with deionized water and ethanol, and dried. The resulting product was named 1-NiSb / Ni₃S₂ / NF.

[0036] Example 2

[0037] The composite material was synthesized according to the scheme of Example 1, except that the amount of potassium pyroantimonate was changed to 2 mmol. The obtained product was recorded as 2-NiSb / Ni3S2 / NF.

[0038] Example 3

[0039] The composite material was synthesized according to the scheme of Example 1, except that the amount of potassium pyroantimonate was changed to 3 mmol. The obtained product was recorded as 3-NiSb / Ni3S2 / NF.

[0040] Comparative Example 1

[0041] The composite material was synthesized according to the scheme of Example 1, except that the amount of potassium pyroantimonate was changed to 0.5 mmol (0.128 g). The obtained product was recorded as 0.5-Ni3S2 / NF.

[0042] Comparative Example 2

[0043] The composite material was synthesized according to the scheme of Example 1, except that the amount of potassium pyroantimonate was changed to 4 mmol (1.015 g). The obtained product was recorded as 4-NiSb / NF.

[0044] Comparative Example 3

[0045] The composite material was synthesized according to the scheme of Example 1, without adding potassium pyroantimonate. Other aspects were the same as in Example 1. The obtained product was recorded as Ni3S2 / NF.

[0046] Characterization of Antimony-Containing Nickel-Based Composites

[0047] X-ray diffraction (XRD) characterization

[0048] Taking 1-NiSb / Ni3S2 / NF prepared in Example 1 as an example, XRD was used to characterize the structure and composition of the NiSb / Ni3S2 / NF composite material and the composite material prepared in the comparative example. Figure 1 (a)), the diffraction peaks observed at 2θ of 44.5°, 51.8° and 76.4° (marked with the symbol “☆” in the figure) are attributed to Ni 0(111), (200) and (220) planes of Ni3S2(JCPDS card No. 04-0850). In addition, a series of diffraction peaks appeared at 2Θ = 21.8°, 31.1°, 37.8°, 44.3°, 50.1° and 55.3° (marked with symbol "△" in the figure), which were attributed to the (101), (110), (003), (202), (211) and (300) planes of Ni3S2(JCPDS card No. 44-1418), respectively. It indicated that the as-prepared product was a mixture of Ni3S2and Ni 0 When the Sb source was regulated, 0.5 mmol Sb source was added, as shown in (b) of Figure 1 , the obtained product 0.5-Ni3S2 / NF also only observed the diffraction peaks of Ni 0 and Ni3S2above. It proved that when the amount of Sb added was low, the Ni on the surface of NF preferentially reacted with sulfur to form Ni3S2. When more Sb source was added to 1 mmol (c) of Figure 1 , the presence of Ni3S2and Ni 0 was still observed in the product. It is worth noting that new diffraction peaks appeared at 2Θ = 31.5° and 46.1° (marked with symbol "□" in the figure), which were attributed to the (101) and (110) planes of NiSb(JCPDS No. 41-1471), respectively. It indicated that when a certain amount of Sb source was added, NiSb, Ni3S2and Ni 0 coexisted. For the composite material prepared in Example 2-3, the coexistence of Ni3S2phase and NiSb was also observed. When more Sb source (4 mmol) was added, as shown in (d) of Figure 1 , the Ni3S2phase disappeared, and only the diffraction of Ni 0 and NiSb was observed, indicating that when the Sb source was excessive, the new phase NiSb was preferentially formed.

[0049] Scanning electron microscopy (SEM) characterization

[0050] The morphology of NiSb / Ni3S2 / NF was characterized by SEM. Figure 2 It can be seen that the bare NF substrate has a smooth surface and a porous three-dimensional framework structure, and such a three-dimensional skeleton is conducive to the contact of adsorption sites with iodine vapor. The morphology of the composite material synthesized in the examples and comparative examples is shown in Figure 3 . For the control sample Ni3S2 / NF without adding Sb (a)-(a") in Figure 3 , it was found that a layer of fluffy sheet with irregular cracks was grown on the surface of NF under high magnification, which was different from the smooth morphology of the bare NF substrate. When 0.5 mmol Sb source was added (b)-(b") in Figure 3(b)-(b”) in the figure, the morphology of the obtained 0.5-Ni3S2 / NF changed significantly, and many spherical protrusions were observed on the surface of the NF skeleton under high magnification ( Figure 3 (b') in the figure), further magnification reveals that these spheres are composed of tightly connected ultrathin nanosheets ( Figure 3 (b”)). The morphology of 1-NiSb / Ni3S2 / NF obtained by adding 1mmol Sb source shows a spherical morphology ( Figure 3 (c)-(c”) in the figure, under magnification, it can be observed that the nanosheets are transformed into loose and uniformly distributed micron-spheres, which may be due to the formation of a new phase NiSb. The loose structure easily exposes adsorption sites, which is conducive to contact with iodine. Compared with the nanosheet morphology of 0.5-Ni3S2 / NF, the microspherical morphology of 1-NiSb / Ni3S2 / NF is not conducive to the adsorption of iodine. However, due to the formation of a new phase of NiSb, this phase contains zero-valent Ni and zero-valent Sb, which can undergo redox reactions with I2 molecules, which is conducive to the improvement of iodine adsorption. When the amount of Sb source added is increased to 4 mmol, the obtained 4-NiSb / NF all presents a micron-spherical morphology ( Figure 3 (d)-(d”) in the figure), but the magnified image shows that the microspheres are closely attached to the NF skeleton, which is not conducive to the exposure of adsorption sites. In addition, this phase only contains two types of metal phases, NiSb / Ni (NiSb can be called an intermetallic compound (or alloy), and NF is the metal phase Ni). The absence of sulfur ions affects the attraction of I2 by soft and hard acid-base interactions, ultimately reducing the adsorption of iodine.

[0051] The element distribution test of the composite material 1-NiSb / Ni3S2 / NF containing two phases of NiSb and Ni3S2 was carried out ( Figure 4 ), observing that Ni, Sb, and S elements are uniformly distributed across the micro / nanospheres. The spherical morphology of the material exposes as many active sites as possible, facilitating contact with iodine during adsorption and enhancing its adsorption efficiency.

[0052] Chemical valence analysis

[0053] XPS was used to characterize the chemical valence state of 1-NiSb / Ni3S2 / NF. Figure 5 As shown in the figure, Ni, Sb and S elements can be observed in the whole spectrum. Figure 5 In (b), the two main peaks at 530.8 and 539.7 eV correspond to Sb 3+ 3D 5 / 2 and 3D 3 / 2 , the two weaker peaks at 528.4 and 537.9 eV are attributed to Sb 0 3D 5 / 2 and 3D3 / 2 In addition, the binding energy of 532.8 eV is related to the lattice O 2- This indicates that there is slight oxidation on the surface of the sample. Ni 2p spectrum ( Figure 5 (c)) Ni was observed 2+ 2p 3 / 2 (854.5eV) and Ni 2+ 2p 1 / 2 (872.7eV), indicating that Ni 2+ The presence of NiSb or Ni3S2 and a weak peak at the binding energy of 852.4 eV are attributed to the zero-valent nickel (Ni 0 ). In the S2p spectrum, Figure 5 (d) shows two peaks at 161.8 and 163.0 eV, corresponding to S 2- 2p 3 / 2 and S 2- 2p 1 / 2 , and SO4 2- The presence of oxidized carbon indicates that the sample surface is slightly oxidized.

[0054] Study on iodine adsorption properties of nickel-based composite materials containing antimony

[0055] (1) Determination of maximum iodine adsorption capacity

[0056] Non-radioactive I2 was used for iodine adsorption experiments. 0.20g I2 was placed at the bottom of the vial, 0.05g adsorbent was placed on the top of the vial, and the top of the vial was supported by filter paper. The vial was sealed and placed in a covered glass bottle to prevent iodine vapor from leaking and ensure that heat was evenly transferred to the vial. Adsorbed in a forced air drying oven at 80°C and ambient pressure for 24 hours, and ventilated in a fume hood for 1 minute. The purple iodine vapor in the bottle quickly escaped from the bottle. The solid sample after iodine adsorption was weighed, and the iodine adsorption amount q was calculated by the mass difference before and after adsorption according to formula (1). e :

[0057]

[0058] Where: m1 (mg) is the initial mass of the adsorbent;

[0059] m2 (mg) is the mass of the adsorbent after adsorption of iodine;

[0060] q e (mg / g) is the adsorption amount at adsorption equilibrium.

[0061] The experimental results are as follows Figure 6As shown. Compared with the iodine adsorption capacity of Ni3S2 / NF synthesized without adding Sb source (1511 mg / g), the adsorption capacity of 0.05-Ni3S2 / NF synthesized by adding 0.5 mmol Sb source increased to 1664 mg / g, which may be mainly due to the introduction of Sb source changing the morphology of the material. The material presents a spherical morphology composed of tightly connected ultra-thin nanosheets, which is conducive to exposing adsorption sites and allowing the material surface to fully contact with iodine. In addition, the sample 1-NiSb / Ni3S2 / NF obtained by adding 1 mmol Sb source contains two phases of NiSb and Ni3S2. Its iodine capture performance is significantly higher than that of 0.5-Ni3S2 / NF and 4-NiSb / NF, highlighting the role of NiSb / Ni3S2 / NF composite materials in iodine adsorption. Comparison of the three materials shows that 1-NiSb / Ni3S2 / NF has the largest iodine adsorption capacity of 1786 mg / g, which is higher than the adsorption capacity of 0.5-Ni3S2 / NF (1664 mg / g) and 4-NiSb / NF (1711 mg / g). For 0.5-Ni3S2 / NF, its adsorption performance may be limited by the absence of the NiSb phase, while the presence of Ni3S2 was not observed in 4-NiSb / NF. The optimized 1-NiSb / Ni3S2 / NF contains both NiSb and Ni3S2 phases, and the synergistic effect between them improves the iodine capture performance. The adsorption performance of NiSb / Ni3S2 / NF is due to the key role played by the NiSb alloy phase obtained by introducing the antimony source in iodine capture. On the other hand, the spherical morphology of the material can better expose the adsorption sites, making it easier for iodine to contact the material surface and improve the adsorption efficiency.

[0062] (2) Iodine desorption experiment

[0063] The iodine-loaded sample (the sample after iodine adsorption during the maximum iodine adsorption determination) was placed in a glass container and heated at 80°C for 2 hours in a vacuum drying oven (vacuum level 0.09 MPa) to release molecular iodine physically adsorbed on the surface or iodine captured by the interaction of soft and hard acids and bases. The remaining iodine adsorption after desorption was calculated using Equation (2).

[0064]

[0065] Where: m1 (mg) is the initial mass of the adsorbent

[0066] m2′ (mg) is the mass of the sample after desorption operation (the sample is still loaded with iodine at this time)

[0067] q e '(mg / g) is the amount of iodine adsorption remaining after desorption

[0068] Experimental results: After desorption, the amount of iodine adsorbed by 0.5-Ni3S2 / NF, 1-NiSb / Ni3S2 / NF and 4-NiSb / NF were 1487, 1658 and 1589 mg / g respectively (see Figure 6 ), accounting for 92% to 97% of the initial adsorption capacity. Under the desorption conditions of 80°C and vacuum degree of 0.09 MPa, the iodine that is not desorbed corresponds to the iodine captured by the redox reaction (REDOX). The above high ratio (the ratio of the iodine adsorption after desorption to the initial maximum iodine adsorption) indicates that this type of adsorbent mainly captures iodine by means of REDOX. In addition, due to the S in sulfide 2- It has soft Lewis base properties and has a high affinity for I2, which is a soft Lewis acid. It is speculated that the small amount of iodine released by the decompression + heating treatment may come from I2 captured by the action of soft and hard acids and bases. Moreover, this high ratio also shows that the iodine captured by the material through REDOX is not easily desorbed, showing good stability, thereby achieving stable solidification of gaseous iodine. In addition, the iodine adsorption residual amount after desorption of 1-NiSb / Ni3S2 / NF (1658 mg / g) is significantly higher than that of the control samples Ni3S2 / NF, 0.5-Ni3S2 / NF and 4-NiSb / NF (1367, 1487 and 1589 mg / g), proving that the coexistence of NiSb, Ni3S2 and Ni enhances the adsorption capacity of the composite material for iodine.

[0069] (3) Adsorption kinetics

[0070] To investigate the adsorption kinetics of NiSb / Ni3S2 / NF, the iodine adsorption capacity was studied over time in a saturated iodine vapor environment. Specifically, the adsorption kinetics experiment was conducted using 0.05g of adsorbent material and 0.2g of iodine. The iodine adsorption capacity was measured and calculated after different adsorption times (0.5, 1, 2, 3, 4, 5, 6, 8, 12, 16, and 24h).

[0071] The experimental results are as follows Figure 7 As shown in Figure 2, within the first 6 hours, the adsorption of iodine by 1-NiSb / Ni3S2 / NF increased rapidly, reaching 90% of the equilibrium adsorption capacity. This is because in the initial stage, the Ni exposed on the NF surface 0 、Sb 0 and S 2- As adsorption sites, they quickly react chemically with I2. As adsorption proceeds, the adsorption sites on the surface are used up, and the sites inside the solid adsorbent material are difficult to contact with iodine, and the adsorption rate slows down until the adsorption reaches equilibrium.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. An antimony-containing nickel-based composite material, characterized in that: include: Nickel foam, and An antimony-containing composite body grown on the nickel foam comprises a NiSb phase and a Ni3S2 phase.

2. The antimony-containing nickel-based composite material according to claim 1, characterized in that The antimony-containing composite has a spherical morphology.

3. The antimony-containing nickel-based composite material according to claim 1, characterized in that The antimony-containing composite is prepared by reacting an antimony source and a sulfur source in a molar ratio of 1:(0.21-0.65) with a stoichiometric excess of a nickel source.

4. The antimony-containing nickel-based composite material according to any one of claims 1 to 3, characterized in that The antimony source is potassium pyroantimonate, the sulfur source is elemental sulfur, and / or the nickel source is foamed nickel.

5. A method for preparing an antimony-containing nickel-based composite material, characterized in that: include: An antimony source and a sulfur source in a molar ratio of 1:(0.21-0.65) are mixed with a stoichiometric excess of a nickel source and then subjected to a solvothermal reaction.

6. The preparation method according to claim 5, characterized in that The solvent for the solvothermal reaction is a mixed solvent of ethylene glycol and water. Preferably, the volume ratio of ethylene glycol to water is 20:

8.

7. The preparation method according to claim 5, characterized in that The temperature of the solvent thermal reaction is 160-200° C., and the reaction time is 6-12 hours.

8. The preparation method according to claim 5, characterized in that The antimony source is potassium pyroantimonate, the sulfur source is elemental sulfur, and / or the nickel source is foamed nickel.

9. The preparation method according to any one of claims 5 to 8, characterized in that include: Dissolving potassium pyroantimonate, sulfur powder, and citric acid in a mixed solvent to obtain a mixed solution; In the presence of hydrazine hydrate, the mixed solution is brought into contact with nickel foam and a solvothermal reaction is performed.

10. Use of the antimony-containing nickel-based composite material according to any one of claims 1 to 4 as an iodine adsorbent.

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