N-doped NiS nanoparticles and their preparation method and application

Abstract

The invention relates to N-doped NiS nano-microspheres and a preparation method and application thereof. The preparation method of the N-doped NiS nano-microspheres comprises the following steps: first, weighing NiCl2·6H2O and thiourea (CH4N2S) according to the molar ratio of each atom in the chemical formula NiS; then weighing a complexing agent accounting for 0.5% to 2.5% of the total weight of the NiCl2·6H2O and thiourea, and a N-introducing agent accounting for 1.0% to 3.0% of the total weight of the NiCl2·6H2O and thiourea; then, placing the raw materials in a beaker, adding a solvent, stirring and dissolving to form a solution, transferring the solution to a reactor, and reacting the solution at 180° C. to 220° C. and a rotation speed of 180-220 rpm / min for 8 to 16 hours; naturally cooling the solution to room temperature, washing, centrifuging, separating the powder, and drying the powder to obtain the N-doped NiS nano-microspheres; the obtained nano-microspheres have regular morphology, good size uniformity, and excellent adsorption performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterial preparation, and in particular relates to an N-doped NiS nano-microsphere and a preparation method and application thereof. Background Art

[0002] Under the "dual carbon" strategy of carbon peak and carbon neutrality, nuclear energy has become an important option for my country's energy transformation. As a clean energy, nuclear energy has become an indispensable and important clean energy to replace highly polluting fossil energy due to its advantages such as clean and pollution-free, high energy density, low comprehensive cost, and no power supply gap, in order to solve my country's air pollution problem. While the nuclear fuel in the nuclear power plant produces a large amount of nuclear energy during the nuclear reaction process, it also produces a large amount of radioactive fission products. Under the bombardment of neutrons, the nuclear fuel 235 U undergoes fission to produce 90 Sr, 89 Sr and some short-lived isotopes 91 Sr- 102 Sr, among which 90 The fission yield of Sr can reach 5.8%. Therefore, in nuclear power plants, whether it is spent fuel, nuclear waste, or discharged effluent, it contains a certain concentration of Sr. 90 Sr. Due 90 Sr has a high fission yield, a long half-life and is easy to migrate. Once released into the environment, it is easy to enter the human skeleton through the food chain and accumulate. 90 Sr emits high-energy β rays during the decay process, which can easily cause significant radiation damage to the bone marrow hematopoietic tissue and bones. 90 Sr not only has a great impact on human tissue and health, but also has a great impact on the surrounding ecological environment. Therefore, the national nuclear power safety supervision department attaches great importance to 90 Sr emission, 90 The monitoring of Sr is one of the main regulatory items for effluent emissions from nuclear power plants. Therefore, the development of an efficient, rapid and specific adsorption material for radioactive Sr is particularly critical.

[0003] Adsorption materials can effectively adsorb certain substances from the gas phase or liquid phase. The main indicators for measuring whether an adsorption material is good are: specific surface area, pore structure, surface functional groups, hydrothermal stability, etc. Good adsorption materials often have excellent adsorption properties, usually with large specific surface area, many surface active functional groups, good pore structure, large pore volume, good regeneration, low environmental pollution, and easy recycling. The principle of adsorption is to use the material's rich pore structure and large specific surface area to construct space, which is conducive to the occurrence of adsorption. With the continuous deepening of research on adsorption materials, the specific surface area, porosity and size of adsorption materials have been continuously broken through, and advanced nano-adsorption materials have been born. The combination of surface chemistry, chemical engineering and nanotechnology has opened up an attractive direction for the treatment of radioactive wastewater. The nano-adsorbents obtained by surface modification have been successfully proven to have excellent adsorption efficiency and can effectively remove pollutants and heavy metal pollution in wastewater. Among the many high specific surface area nanomaterials, sulfide nanomaterials have attractive prospects in the field of adsorption of radioactive Sr in wastewater due to their unique properties. S 2– It is a soft base ion and has no effect on soft acid ions (such as Hg 2+ , Pb 2+ 、Cd 2+ 、Ni 2+ 、Co 2+ 、UO2 2+ 、Cs + and Sr 2+ etc.) has a strong affinity and high selectivity, while it has a strong affinity and high selectivity for hard acid ions (such as H + 、Na + and Ca 2+ When metal sulfide is used as an adsorbent to treat heavy metal ions or radionuclides, its adsorption performance is affected by H + 、Na + and Ca 2+ The negative impact of metal sulfide adsorbents is less than that of traditional adsorbents (such as activated carbon, zeolite, clay, monometallic oxides, etc.). Therefore, metal sulfide adsorbents can be used to treat wastewater with a wide pH distribution range and high salt concentration.

[0004] Currently, the materials used to adsorb radioactive strontium from nuclear wastewater are primarily organic, including crown ether resins and chromatography resin powders. These materials suffer from drawbacks such as lengthy synthesis steps, complex preparation processes, numerous intermediates, large amounts of solvent used in the extraction process, and difficulty in recovering them. Furthermore, organic polymer chemical materials have stringent requirements for synthesis and preparation conditions. In recent years, metal-organic frameworks (MOFs) have also been used in some applications for adsorbing metal ions from wastewater. However, factors such as the type of coordination compounds, preparation costs, and difficulty in obtaining crystal forms have limited their commercialization and industrialization. Inorganic nanomaterials prepared by hydrothermal methods, on the other hand, are a popular method for preparing materials due to their simple preparation process, simple preparation conditions, low energy consumption, easy access to high-purity, high-quality crystal forms, effective avoidance of hard agglomerates, and excellent dispersion. Furthermore, magnetic nanomaterials are readily separable and recyclable, allowing for reuse and minimizing the generation of harmful substances, making them an important research area for environmentally friendly adsorption materials. In addition, surface modification methods are used to modify organic groups on the surface of magnetic nanomaterials, and the interaction between metal ions and organic groups, including surface complexation, cation-π bonding, π-π bonding, H bonding, etc., is used to improve the adsorption performance of the material. Surface modification of nanomaterials enriches the surface functional groups of the material and can significantly increase the surface activity of the material, becoming an important direction for improving the adsorption performance of the material. At present, the research and application of sulfide magnetic nanomaterials in China mainly focus on photoelectrocatalysis, lithium batteries and supercapacitors, and biopharmaceuticals. There are few reports on their application in the adsorption of radioactive nuclides in nuclear waste liquids. In particular, there are almost no reports on the application of sulfide magnetic adsorption nanospheres for the adsorption of radioactive Sr in nuclear waste liquids.

[0005] The present invention utilizes a hydrothermal method to innovatively prepare N-doped NiS nanospheres. The entire preparation process is simple, the preparation conditions are simple, and the energy consumption is low. The prepared crystals are nanoscale in size with good size uniformity. The nanospheres have excellent adsorption properties and have the potential for industrial production and application. They have potential application and development value in the field of adsorption of radioactive Sr in nuclear waste liquid. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects existing in the preparation of nano-adsorption materials, such as long preparation cycle, low preparation efficiency, complicated preparation process, harsh preparation conditions, poor uniformity and dispersion of prepared small particles, and difficulty in separating and recovering materials. By using a hydrothermal method, a preparation method of novel N-doped NiS nano-microspheres is provided, which have short preparation cycle, simple operation process, simple preparation conditions, good uniformity and dispersion of nano-particles, easy separation and recovery, rich surface functional groups, and excellent adsorption performance, as well as the N-doped NiS nano-microspheres prepared by the method and applications thereof.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for preparing N-doped NiS nanospheres comprises the following steps:

[0009] Step (1) Weighing of raw materials: According to the molar ratio of each atom in the chemical formula NiS, weigh the following reaction raw materials: 0.01-0.05 mol NiCl2·6H2O, 0.02-0.10 mol thiourea (CH4N2S);

[0010] Next, weighing 0.5% to 2.5% of a complexing agent based on the total weight of NiCl2·6H2O and thiourea (CH4N2S), and 1.0% to 3.0% of a nitrogen-introducing agent based on the total weight of NiCl2·6H2O and thiourea (CH4N2S);

[0011] Step (2) reaction:

[0012] The raw materials weighed in step (1) are placed in a beaker, a solvent is added, and the mixture is stirred and dissolved to form a solution, which is then transferred to a hydrothermal reactor. The mixture is then reacted at 180° C. to 220° C. and a rotation speed of 180-220 rpm / min for 8 to 16 hours. After naturally cooling to room temperature, the mixture is washed with deionized water and anhydrous ethanol, and the powder is separated by centrifugation and dried to obtain black N-doped NiS nanospheres.

[0013] Wherein, the complexing agent is one of cetyltrimethylammonium bromide (CTAB), ethylenediaminetetraacetic acid (EDTA), ethylene glycol ditetraacetic acid (EGTA), diethylenetriaminepentaacetic acid (DTPA), and hydroxyethylethylenediaminetriacetic acid (HEDTA);

[0014] The N-introducing agent is one of 2,4-diaminobenzenesulfonic acid, p-aminobenzenesulfonic acid, benzenesulfonic acid, 4-aminobenzoic acid, and aminophenylboronic acid.

[0015] The solvent is one of ethylene glycol, ethanol, isopropanol, butanol, and propylene glycol, or a mixture of several of them.

[0016] The specific operation method of step (2) is:

[0017] The raw materials weighed in step (1) are placed in a beaker, a solvent is added, and the mixture is stirred and dissolved to form a solution, which is then transferred to a hydrothermal reactor. The mixture is then reacted at 180° C. to 220° C. and a rotation speed of 180-220 rpm / min for 8 to 16 hours. After naturally cooling to room temperature, the mixture is washed with deionized water and anhydrous ethanol, and the powder is separated by centrifugation. The powder is then freeze-dried in a freeze dryer at -45° C. and 20 Pa to obtain black N-doped NiS nanospheres.

[0018] Preferably, the specific operation method of step (2) is:

[0019] The raw materials weighed in step (1) were placed in a beaker, a solvent was added, and the mixture was stirred and dissolved to form a solution, which was then transferred to a hydrothermal reactor. The mixture was then reacted at 200° C. and a rotation speed of 200 rpm / min for 8 to 16 hours. After naturally cooling to room temperature, the mixture was washed with deionized water and anhydrous ethanol, and the powder was separated by centrifugation. The powder was then freeze-dried in a freeze dryer at -45° C. and 20 Pa to obtain black N-doped NiS nanospheres.

[0020] Or the specific operation method of step (2) is:

[0021] The raw materials weighed in step (1) are placed in a beaker, a solvent is added, and the mixture is stirred and dissolved to form a solution, which is then transferred to a hydrothermal reactor. The mixture is then reacted at 180° C. to 220° C. and a rotation speed of 180-220 rpm / min for 8 to 16 hours. After naturally cooling to room temperature, the mixture is washed with deionized water and anhydrous ethanol, and the powder is separated by centrifugation. The powder is then vacuum dried at 60° C. (the vacuum degree can be conventionally -0.08 MPa) to obtain black N-doped NiS nanospheres.

[0022] Preferably, the complexing agent is cetyltrimethylammonium bromide (CTAB), and the added amount of the complexing agent is 1.5% of the total weight of NiCl2·6H2O and thiourea (CH4N2S).

[0023] Preferably, the N-introducing agent is 2,4-diaminobenzenesulfonic acid, and the added amount of the N-introducing agent is 2.0% of the total weight of NiCl2·6H2O and thiourea (CH4N2S).

[0024] The present invention also provides N-doped NiS nano-microspheres prepared by the preparation method, and application of the N-doped NiS nano-microspheres in preparing an adsorption material for Sr adsorption.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] 1. The preparation cycle of the present invention is short and the operation process is simple. The required preparation cycle is controlled within 24 hours. The operation process only includes the steps of weighing, dissolving, mixing, stirring, heat preservation, filtering, washing, and drying, which is simple and easy to carry out.

[0027] 2. The preparation equipment of the present invention is simple and has high preparation efficiency. The required equipment is glassware and drying oven commonly used in the laboratory. Multiple hydrothermal kettles used in the preparation can be used simultaneously, which greatly improves the preparation efficiency.

[0028] 3. The preparation cost of the present invention is low, and it is green, clean and pollution-free. The raw materials in the preparation process are cheap and easily available, the drying oven involved only consumes a small amount of electricity, the added solute reacts completely, the amount of aqueous solution is small, and the environmental pollution is small.

[0029] 4. The nano-microspheres prepared by the present invention have regular morphology, good size uniformity and excellent adsorption performance. The morphology is regular spheres, and the size is uniform and basically stable at about 600nm. The adsorption performance is excellent after testing. 2+ The adsorption capacity of ions is 102.6 mg / g, and the adsorption capacity of Sr 2+ The ion removal rate reached 94.7%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the XRD test spectrum of Example 1 of the present invention.

[0031] Figure 2 This is a scanning electron microscope image of Example 1 of the present invention.

[0032] Figure 3 This is the adsorption equilibrium curve of Example 1 of the present invention.

[0033] Figure 4 For Sr in Example 1 of the present invention 2+ Removal rate curve. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the accompanying drawings and embodiments:

[0035] Example 1:

[0036] The following reaction materials were weighed according to the molar ratio of each atom in the chemical formula NiS: 0.02 mol NiCl2·6H2O and 0.06 mol thiourea (CH4N2S). A chelating agent, cetyltrimethylammonium bromide (CTAB), was added at a concentration of 1.5% based on the combined weight of NiCl2·6H2O and thiourea (CH4N2S). A nitrogen-introducing agent, 2,4-diaminobenzenesulfonic acid, was also added at a concentration of 2.0% based on the combined weight of NiCl2·6H2O and thiourea (CH4N2S). The reaction materials were placed in a 50 mL beaker, and 30 mL of ethylene glycol was added. The solution was stirred and dissolved, then transferred to a 50 mL hydrothermal reactor and reacted at 200°C and 200 rpm / min for 15 hours. After cooling to room temperature, the solution was washed with deionized water and anhydrous ethanol, separated by centrifugation, and freeze-dried in a freeze dryer at -45°C and 20 Pa to obtain black, nitrogen-doped NiS nanospheres.

[0037] Figure 1: is the XRD pattern of this embodiment. The characteristic peaks in the pattern all correspond to the characteristic peaks of the NiS phase, indicating that pure NiS nanoparticles have been successfully prepared. Figure 2 This is a scanning electron microscope picture of this embodiment. It can be seen from the picture that the nanomaterial is a regular spherical structure with a size of 600nm. Figure 3 The adsorption equilibrium curve of this embodiment is well fitted with the Langmuir-Freundlich isotherm model (correlation coefficient R 2 =0.995), where Sr 2+ The maximum adsorption capacity is 102.6 mg / g. Figure 4 The adsorption removal rate curve of this embodiment is shown in Figure 2. The adsorption equilibrium is reached in 24 hours, and the removal rate is 94.7%. The data can be fitted with a pseudo-second-order model (correlation coefficient R 2 =0.992). Figure 3 and Figure 4 The curve and results show that N-doped NiS nanospheres have a great influence on Sr 2+ Excellent ion adsorption performance.

[0038] Example 2:

[0039] The following reaction materials were weighed according to the molar ratio of each atom in the chemical formula NiS: 0.02 mol NiCl2·6H2O and 0.06 mol thiourea (CH4N2S). A chelating agent, cetyltrimethylammonium bromide (CTAB), was added at a rate of 1.5% based on the combined weight of NiCl2·6H2O and thiourea (CH4N2S). A nitrogen-introducing agent, 2,4-diaminobenzenesulfonic acid, was also added at a rate of 2.0% based on the combined weight of NiCl2·6H2O and thiourea (CH4N2S). The reaction materials were placed in a 50 mL beaker, and 30 mL of ethylene glycol was added. The solution was stirred and dissolved, then transferred to a 50 mL hydrothermal reactor and reacted at 200°C and 200 rpm / min for 15 hours. After cooling to room temperature, the solution was washed with deionized water and anhydrous ethanol, centrifuged, and vacuum-dried at 60°C to obtain black, nitrogen-doped NiS nanospheres.

[0040] In order to better explore the effects of the feed ratio of each raw material, reaction conditions, and drying method on the performance of the obtained N-doped NiS nanospheres, the inventors also carried out other examples as shown in Table 1. The products obtained in each example were verified by XRD patterns. It was verified that the characteristic peaks in the patterns of the products obtained in each example corresponded to the characteristic peaks of the NiS phase, indicating that pure phase NiS nanospheres were successfully prepared in each example. The inventors conducted XRD on the particle size, Sr 2+ The maximum adsorption capacity of Sr 2+The removal rate was tested and the test results are shown in Table 1.

[0041] Among them, Sr 2+ The adsorption capacity of Sr 2+ The test method for removal rate is:

[0042] Adsorption isotherm (Sr 2+ Adsorption capacity): configure a series of different concentrations of Sr 2+ solution, 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 100ppm, 150ppm, 200ppm, 300ppm, 400ppm, 600ppm. N-doped NiS nanospheres were added to different initial concentrations of Sr 2+ After adsorption equilibrium, the Sr 2+ The concentration of Sr is plotted. 2+ The adsorption isotherm.

[0043] Sr 2+ Removal rate curve: Sr is configured at a concentration of 100 mg / L 2+ 5 mL of the solution was placed in a centrifuge tube, and N-doped NiS nanospheres were added at a solid-liquid ratio of 10 g / L, and the solution was shaken at room temperature. After a period of time, the clear solution was filtered with a filter membrane and sampled to determine the Sr content in the solution. 2+ The concentration of Sr is plotted based on the concentration and time curve. 2+ Removal rate curve.

[0044] Table 1

[0045]

[0046] From the data in Table 1, it can be seen that the N-doped NiS nanospheres prepared by the preparation method described in Example 1 of the present invention have the best performance and are expected to be used in the preparation of adsorption materials for Sr adsorption.

[0047] The inventors also tried to introduce other complexing agents and N-introducing agents to prepare N-doped NiS nanospheres. The specific operation method is as follows:

[0048] Example 11

[0049] The following reaction materials were weighed according to the molar ratio of each atom in the chemical formula NiS: 0.02 mol NiCl2·6H2O and 0.06 mol thiourea (CH4N2S). Ethylene glycol ditetraacetic acid (EGTA) was added as a complexing agent at a rate of 1.5% based on the combined weight of NiCl2·6H2O and thiourea (CH4N2S); and benzenesulfonic acid, a nitrogen-introducing agent, was added at a rate of 2.0% based on the combined weight of NiCl2·6H2O and thiourea (CH4N2S). The reaction materials were placed in a 50 mL beaker, and 30 mL of ethanol was added. The solution was then stirred and dissolved, transferred to a 50 mL hydrothermal reactor, and reacted at 200°C and 200 rpm / min for 12 hours. After cooling to room temperature, the solution was washed with deionized water and anhydrous ethanol, centrifuged, and dried at 60°C to obtain black, N-doped NiS nanospheres.

[0050] The test results show that the pure phase NiS nanoparticles were successfully prepared in this embodiment. 2+ The adsorption performance is also inferior to that of the N-doped NiS nanospheres obtained in Example 1.

[0051] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for preparing N-doped NiS nanospheres, characterized in that: It includes the following process steps: Step (1) Weighing of raw materials: According to the molar ratio of each atom in the chemical formula NiS, weigh the following reaction raw materials: 0.01-0.05 mol NiCl2·6H2O, 0.02-0.10 mol thiourea (CH4N2S); Next, weighing 0.5% to 2.5% of a complexing agent based on the total weight of NiCl2·6H2O and thiourea (CH4N2S), and 1.0% to 3.0% of a nitrogen-introducing agent based on the total weight of NiCl2·6H2O and thiourea (CH4N2S); Step (2) reaction: The raw materials weighed in step (1) are placed in a beaker, a solvent is added, and the mixture is stirred and dissolved to form a solution, which is then transferred to a hydrothermal reactor. The mixture is then reacted at 180° C. to 220° C. and a rotation speed of 180-220 rpm / min for 8 to 16 hours. After naturally cooling to room temperature, the mixture is washed with deionized water and anhydrous ethanol, and the powder is separated by centrifugation and dried to obtain black N-doped NiS nanospheres. Wherein, the complexing agent is one of cetyltrimethylammonium bromide (CTAB), ethylenediaminetetraacetic acid (EDTA), ethylene glycol ditetraacetic acid (EGTA), diethylenetriaminepentaacetic acid (DTPA), and hydroxyethylethylenediaminetriacetic acid (HEDTA); The N-introducing agent is one of 2,4-diaminobenzenesulfonic acid, p-aminobenzenesulfonic acid, benzenesulfonic acid, 4-aminobenzoic acid, and aminophenylboronic acid.

2. The method for preparing N-doped NiS nanospheres according to claim 1, wherein: The solvent is one of ethylene glycol, ethanol, isopropanol, butanol, and propylene glycol, or a mixture of several of them.

3. The method for preparing N-doped NiS nanospheres according to claim 1, wherein: The specific operation method of step (2) is: The raw materials weighed in step (1) are placed in a beaker, a solvent is added, and the mixture is stirred and dissolved to form a solution, which is then transferred to a hydrothermal reactor. The mixture is then reacted at 180° C. to 220° C. and a rotation speed of 180-220 rpm / min for 8 to 16 hours. After naturally cooling to room temperature, the mixture is washed with deionized water and anhydrous ethanol, and the powder is separated by centrifugation. The powder is then freeze-dried in a freeze dryer at -45° C. and 20 Pa to obtain black N-doped NiS nanospheres.

4. The method for preparing N-doped NiS nanospheres according to claim 1, wherein: The specific operation method of step (2) is: The raw materials weighed in step (1) were placed in a beaker, a solvent was added, and the mixture was stirred and dissolved to form a solution, which was then transferred to a hydrothermal reactor. The mixture was then reacted at 180° C. to 220° C. and a rotation speed of 180-220 rpm / min for 8 to 16 hours. After naturally cooling to room temperature, the mixture was washed with deionized water and anhydrous ethanol, and the powder was separated by centrifugation. The powder was then vacuum dried at 60° C. to obtain black N-doped NiS nanospheres.

5. N-doped NiS nanoparticles prepared by the preparation method according to any one of claims 1 to 4. 6 . Use of the N-doped NiS nanoparticles according to claim 5 in preparing an adsorption material for Sr adsorption.

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