Cobalt nano-particle / graphite-acetylene nano-composite catalytic material as well as preparation method and application thereof

Abstract

The invention discloses a cobalt nanoparticle / graphite-alkyne nano-composite catalytic material and a preparation method and application thereof.The preparation method comprises the following steps that graphite-alkyne is obtained and mixed with cobalt salt, nitrogen, nitrogen-dimethylformamide and absolute ethyl alcohol to prepare a mixed solution, the mixed solution is subjected to solvothermal reaction and calcination, and the cobalt nanoparticle / graphite-alkyne nano-composite catalytic material is obtained. The nanometer composite catalytic material is obtained. The prepared nano composite catalytic material has the advantages of being large in specific surface area, large in number of active sites, high in cobalt nanoparticle loading capacity, good in cobalt nanoparticle dispersity, high in catalytic activity, good in stability and the like, is a novel cobalt catalyst with excellent catalytic performance and stable structure, can efficiently activate persulfate when being used for activating the persulfate, and has good application prospects. Organic pollutants can be efficiently degraded, the use value is high, and the application prospect is good. The preparation method also has the advantages of simple process, convenience in operation, mild reaction conditions, low cost, environment friendliness and the like, can be used for large-scale preparation, and is convenient for industrial utilization.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of environmental functional nano materials, and relates to a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material and a preparation method and application thereof. Background Art

[0002] As a strong oxidant, persulfate plays an important role in the degradation of environmental pollutants. However, persulfate itself has low activity and usually requires the help of catalysts to activate it to generate strong oxidizing free radicals (such as sulfate radicals and hydroxyl radicals) to enhance the degradation ability of pollutants. Therefore, the key to this technology is to explore economical and efficient Fenton-like catalysts.

[0003] Cobalt nanoparticles have been widely used to activate persulfate because of their excellent conductivity and catalytic properties. During the activation process of persulfate, cobalt nanoparticles react chemically with persulfate molecules through their surface, promoting the decomposition of persulfate and generating highly active free radicals. Although cobalt nanoparticles have shown great potential in activating persulfate, they still have certain disadvantages. First, the relatively small size of cobalt nanoparticles leads to their large surface energy. The high surface energy makes it easy for cobalt nanoparticles to agglomerate during the preparation and catalytic reaction process, resulting in the burial of a large number of active sites. Secondly, cobalt nanoparticles are not easy to recycle during use and may cause secondary pollution to the environment.

[0004] In response to the above problems, the researchers proposed a new idea of ​​loading cobalt nanoparticles on a carrier material to construct a loaded cobalt catalyst. There are two ways to load cobalt nanoparticles: one is to load cobalt nanoparticles on a carrier material, and the other is to coat cobalt nanoparticles in a carrier material. In the first loading method, there are still defects such as poor loading stability of cobalt nanoparticles, uncontrollable dispersion of cobalt nanoparticles on the surface of the carrier material, and easy agglomeration, which is not conducive to improving the catalytic performance of the loaded cobalt catalyst; in the second loading method, although cobalt nanoparticles can be embedded in the carrier material, this loading method cannot control the loading amount of cobalt nanoparticles, and it is difficult to increase the loading amount of cobalt nanoparticles. At the same time, it is also difficult to control the particle size, morphology and dispersibility of cobalt nanoparticles, which is not conducive to the large-scale preparation of loaded cobalt catalysts with excellent performance. Therefore, how to obtain a loaded cobalt catalyst with controllable particle size and morphology, small particle size, controllable loading amount, high loading amount, and good stability is of great significance for effectively activating persulfate and achieving efficient removal of organic pollutants in water. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material with controllable particle size and morphology, small particle size, controllable loading amount, high loading amount and good stability, as well as a preparation method and application thereof.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for preparing a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material comprises the following steps: S1. Obtaining graphene; S2, mixing the graphene-acetylene, cobalt salt, nitrogen, nitrogen-dimethylformamide and anhydrous ethanol obtained in step S1, and performing ultrasonication to obtain a mixed solution; S3, performing a solvothermal reaction on the mixed solution obtained in step S2 to obtain a precursor material; S4, calcining the precursor material obtained in step S3 to obtain cobalt nanoparticles / graphite-acetylene nanocomposite catalytic material.

[0007] The above preparation method is further improved. In step S2, the mass ratio of graphite to cobalt salt is 1:1-16; the cobalt salt is cobalt chloride; the ratio of graphite to nitrogen, nitrogen-dimethylformamide is 0.1 g:30 mL; the ratio of graphite to anhydrous ethanol is 0.1 g:30 mL; and the ultrasonic time is 30 min.

[0008] The above preparation method is further improved, in step S1, the preparation method of graphene-acetylene comprises the following steps: S1-1, mixing benzene and anhydrous ethanol, adding calcium carbide powder to obtain a dispersion; the ratio of the calcium carbide powder, benzene and anhydrous ethanol is 10 g: 2 mL: 35 mL; S1-2, adding the dispersion obtained in step S1-1 and stainless steel beads into a stainless steel ball mill, evacuating the mixture, reacting in a planetary ball mill, washing, and drying; during the reaction, the rotation speed of the planetary ball mill is controlled to be 600 rpm; the reaction time is 24 h; the washing is performed by washing with nitric acid and glacial acetic acid 3 to 5 times respectively; the drying is performed under vacuum conditions; the drying temperature is 60°C, and the drying time is 12 to 24 h; S1-3, annealing the material dried in step S1-2 to obtain graphene; the heating rate during the annealing process is 5°C / min; the annealing temperature is 260°C; and the annealing time is 2 h.

[0009] The above preparation method is further improved, in step S3, the temperature of the solvent thermal reaction is 140° C.; the time of the solvent thermal reaction is 24 h.

[0010] The above preparation method is further improved, wherein after the solvothermal reaction is completed, the following treatment is further included: washing the product after the solvothermal reaction with anhydrous ethanol for 3 to 5 times, and drying it under vacuum conditions at a temperature of 60° C. for 12 h to 24 h to obtain a precursor material; The above preparation method is further improved in that in step S4, the calcination is carried out under a nitrogen atmosphere.

[0011] The above preparation method is further improved, wherein the calcination is first heated to 450°C at a heating rate of 5°C / min, calcined for 2h, and then continued to heat to 700°C and calcined for 1h to obtain cobalt nanoparticles / graphite-acetylene nanocomposite catalytic material.

[0012] As a general technical concept, the present invention also provides a cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material prepared by the above-mentioned preparation method, wherein the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material includes graphite-yne, on which cobalt nanoparticles are anchored; the mass ratio of cobalt nanoparticles to graphite-yne ​​in the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material is 1 to 16:20.

[0013] The above-mentioned cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material is further constructed, wherein the mass ratio of cobalt nanoparticles to graphite-yne ​​in the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material is 1 to 6:10.

[0014] As a general technical concept, the present invention also provides an application of the above-mentioned cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material as a catalyst for activating persulfate in treating organic pollutant wastewater.

[0015] The above application is further improved and includes the following steps: mixing the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material and organic pollutant wastewater, adding persulfate to carry out a Fenton-like catalytic reaction to complete the degradation of organic pollutants in the wastewater.

[0016] The above application is further improved, wherein the added amount of the cobalt nanoparticles / graphite-alkyne nanocomposite catalytic material is 0.05g to 0.2g of the cobalt nanoparticles / graphite-alkyne nanocomposite catalytic material per liter of organic pollutant wastewater.

[0017] The above application is further improved in that the amount of persulfate added is 0.1 g to 0.5 g per liter of organic pollutant wastewater.

[0018] The above application is further improved in that the persulfate is peroxymonosulfate.

[0019] The above application is further improved, wherein the organic pollutants in the organic pollutant wastewater are antibiotics; the initial concentration of the organic pollutants in the organic pollutant wastewater is ≤10 mg / L; and the antibiotic is tetracycline.

[0020] The above application is further improved in that the time of the Fenton-like catalytic reaction is 6 min to 15 min.

[0021] Compared with the prior art, the advantages of the present invention are: (1) In view of the defects of the existing supported cobalt catalysts, such as poor loading stability of cobalt nanoparticles, uncontrollable dispersion and easy agglomeration of cobalt nanoparticles on the surface of carrier materials, difficulty in regulating the particle size, morphology and dispersion of cobalt nanoparticles, uncontrollable loading amount of cobalt nanoparticles and low loading amount, the present invention creatively proposes a method for preparing a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material. Graphite-acetylene is used as a carrier material. Graphite-acetylene, cobalt salt, nitrogen, nitrogen-dimethylformamide and anhydrous ethanol are first mixed and ultrasonicated. A large amount of cobalt ions are uniformly adsorbed on the surface of graphite-acetylene by utilizing the huge specific surface area and abundant adsorption sites of graphite-acetylene. This is the basis for regulating the loading amount and dispersion of cobalt nanoparticles. Then, during the solvent thermal reaction, the cobalt ions are converted into precursor materials that are easy to calcine, which is conducive to reducing the calcination temperature and saving energy. This is one of the key means to improve the uniform dispersion of subsequent cobalt nanoparticles on the surface of graphite-acetylene. On this basis, the precursor material prepared after the solvent thermal reaction is calcined to convert the low-cost, high-cobalt content precursor material into a cobalt nanoparticle with small particle size and good dispersion. Nanoparticles, in particular, the use of two-step calcination is more conducive to increasing the loading amount of cobalt nanoparticles, and with the help of the abundant acetylene bonds on the surface of graphite-yne, the cobalt nanoparticles and the π electrons of the acetylene bonds interact with each other with strong binding force, and then under the promotion of this interaction, the cobalt nanoparticles can be firmly attached to the surface of graphite-yne, and at the same time, the uneven distribution of electrons on the surface of graphite-yne ​​also increases the migration resistance of the cobalt nanoparticles on its surface, which is also conducive to preventing the agglomeration of cobalt nanoparticles, and then can significantly increase the stability and catalytic performance of the cobalt nanoparticles, and finally prepare a cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material with large specific surface area, large number of active sites, high loading amount of cobalt nanoparticles, good dispersibility of cobalt nanoparticles, high catalytic activity and good stability, which is a new type of cobalt catalyst with excellent catalytic performance and stable structure. When the composite catalytic material is used to activate persulfate, the persulfate can be efficiently activated under the joint action of graphite-yne ​​and cobalt nanoparticles, and the constructed degradation system can efficiently degrade organic pollutants, with high use value and good application prospects. At the same time, the preparation method of the present invention also has the advantages of simple process, convenient operation, mild reaction conditions, low cost, green and environmental protection, etc., and can be used for large-scale preparation and is convenient for industrial utilization.

[0022] (2) In the preparation method of the present invention, by optimizing the mass ratio of graphene-acetylene to cobalt salt to 1:1-16, the cobalt nanoparticle loading amount and the better dispersion in the prepared cobalt nanoparticle / graphene-acetylene nanocomposite catalytic material are moderate, and the catalytic performance is more excellent and the structure is more stable, which can meet different application requirements.

[0023] (3) The present invention provides a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material for use as a catalyst for activating persulfate in treating organic pollutant wastewater. Specifically, the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared by the present invention has a large specific surface area, a large number of active sites, a high cobalt nanoparticle loading, good cobalt nanoparticle dispersibility, high catalytic activity and good stability. As a catalyst for activating persulfate, a degradation system containing a large number of free radicals with strong oxidizing effects (such as sulfate radicals and hydroxyl radicals) is quickly formed, thereby achieving efficient degradation of different types of organic pollutants in wastewater. The method has the advantages of simple process, convenient operation, low cost, high treatment efficiency, good removal effect and green environmental protection, and is of great significance for purifying organic pollutant wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0025] Figure 1 This is an X-ray diffraction pattern of the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 2 of the present invention.

[0026] Figure 2 This is the energy spectrum of the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 2 of the present invention.

[0027] Figure 3 This is a Fourier infrared spectrum of the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material prepared in Example 2 of the present invention.

[0028] Figure 4 This is an X-ray photoelectron spectrum of the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 2 of the present invention.

[0029] Figure 5 This is a diagram showing the degradation effect of cobalt nanoparticles / graphite-alkyne nanocomposite catalytic materials (A1, A2, A3) and graphite-alkyne on tetracycline according to Example 4 of the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0031] In the following examples of the present invention, unless otherwise specified, the materials and instruments used are commercially available, the equipment used is conventional equipment, and the data obtained are the average values ​​of more than three repeated experiments.

[0032] Example 1 A method for preparing a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material comprises the following steps: S1. Obtain graphene-acetylene, the preparation method of which is as follows: First, 2 mL of benzene and 35 mL of ethanol were added to a 250 mL stainless steel ball mill, and then 10 g of calcium carbide powder was added to the mixed solution. Then the mixture of the three and the stainless steel beads were added to the stainless steel ball mill, the lid was closed and vacuumed. Then the ball mill was placed on a planetary ball mill and run at 600 rpm for 24 h (resting for 3 min every 6 min to prevent overheating). The obtained material was then washed with nitric acid and glacial acetic acid for 3-5 times, and the washed material was dried in a vacuum drying oven (60 ° C). The dried material was placed in a tubular furnace, and the tubular furnace was heated to 260 ° C at a heating rate of 5 ° C / min, and then annealed at 260 ° C for 2 h to obtain graphene-yne.

[0033] S2, mixing the graphene-acetylene, cobalt salt, nitrogen, nitrogen-dimethylformamide and anhydrous ethanol obtained in step S1, and ultrasonicating to obtain a mixed solution, specifically: 0.1 g of anhydrous cobalt chloride and 0.1 g of graphene prepared in step S1 were added to a mixed solution of 30 mL of nitrogen, nitrogen-dimethylformamide and 30 mL of anhydrous ethanol, and ultrasonicated for 30 min to mix the components evenly to obtain a mixed solution.

[0034] S3, performing a solvothermal reaction on the mixed solution obtained in step S2 to obtain a precursor material, specifically: The mixed solution was transferred to a polytetrafluoroethylene-lined autoclave, and the autoclave was placed in an oven for solvent thermal reaction at 140°C for 24 h. The reacted material was washed 3-5 times with anhydrous ethanol and dried in a vacuum drying oven at 60°C for 12 h to obtain a precursor material.

[0035] S4, calcining the precursor material obtained in step S3 to obtain a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material, specifically: The precursor material was placed in a tubular furnace, first heated to 450 °C at a heating rate of 5 °C / min, and calcined at 450 °C for 2 h; then heated to 700 °C at a heating rate of 5 °C / min, and then calcined at 700 °C for 1 h to obtain cobalt nanoparticles / graphite-acetylene nanocomposite catalytic material, recorded as A1.

[0036] The cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material prepared in this embodiment includes graphite-yne, on which cobalt nanoparticles are anchored, wherein the mass ratio of cobalt nanoparticles to graphite-yne ​​in the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material is 1:20.

[0037] Example 2 A method for preparing a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material is substantially the same as that of Example 1, except that in Example 2, the amount of anhydrous cobalt chloride used is 0.8 g.

[0038] The cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 2 is denoted as A2.

[0039] The mass ratio of cobalt nanoparticles to graphite in the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 2 is 2:5.

[0040] Example 3 A method for preparing a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material is substantially the same as that of Example 1, except that in Example 3, the amount of anhydrous cobalt chloride used is 1.6 g.

[0041] The cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 3 is denoted as A3.

[0042] The cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material prepared in Example 3 includes graphite-yne, on which cobalt nanoparticles are anchored, wherein the mass ratio of cobalt nanoparticles to graphite-yne ​​in the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material is 4:5.

[0043] Figure 1 : is the X-ray diffraction pattern of the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 2 of the present invention. Figure 1 It can be seen that after the cobalt nanoparticles are loaded, compared with the diffraction peak of graphene, the extra diffraction peak of the cobalt nanoparticle / graphene nanocomposite catalytic material corresponds to the peak of the cobalt nanoparticles.

[0044] Figure 2 : is the energy spectrum of the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 2 of the present invention. Figure 2 It can be seen that the composite catalytic material contains carbon, nitrogen, oxygen and cobalt.

[0045] Figure 3 This is a Fourier infrared spectrum of the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared in Example 2 of the present invention. Figure 3It can be seen that in the range of 2000-2300 cm -1 There is stretching vibration of carbon-carbon triple bond at 1400-1500 cm -1 There is CH bending vibration. Cobalt nanoparticles / graphene-acetylene nanocomposite catalytic material and graphene-acetylene have a wavelength of 1400-1500 cm -1 There are slight differences in peak shape, which reflects the interaction between cobalt and carbon atoms.

[0046] Figure 4 This is an X-ray photoelectron spectrum of the cobalt nanoparticle / graphene-acetylene nanocomposite catalytic material prepared in Example 2 of the present invention. Figure 4 In the graph, the peaks mainly appear at 781.6 eV, 786.8 eV, 797.7 eV and 803.6 eV, which is basically consistent with the binding energy of cobalt.

[0047] The above results can prove that the cobalt nanoparticles / graphite-yne ​​nanocomposite catalytic material has been successfully prepared.

[0048] Example 4 A cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material is used as a catalyst for activating persulfate in treating organic pollutant wastewater, specifically: using the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material (A1, A2, A3) prepared in Examples 1-3 as a catalyst for activating persulfate to treat tetracycline wastewater, comprising the following steps: Accurately weigh 0.01 g of graphite-yne ​​and cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic materials (A1, A2, A3), add them to 100 mL and 10 mg / L tetracycline solution, respectively, and stir magnetically in the dark for 30 min to allow tetracycline to reach adsorption-desorption equilibrium on different catalyst surfaces. Then add 30 mg of persulfate (permonosulfate) to carry out Fenton-like catalytic reaction to complete the degradation of tetracycline in the wastewater.

[0049] During the Fenton-like catalytic reaction, 3 mL of the solution was taken every 2 min (a total of 12 min of sampling), and the solution was filtered through a 0.22 µm organic phase filter membrane to remove the catalyst. The concentration of tetracycline in the filtered sample was measured by a UV-visible spectrophotometer, and the degradation efficiency of different catalysts was calculated. The results are shown in Figure 2. Figure 5 shown.

[0050] Figure 5 This is a graph showing the degradation effect of tetracycline by cobalt nanoparticles / graphite-acetylene nanocomposite catalytic materials (A1, A2, A3) and graphite-acetylene in Example 4 of the present invention. Figure 5It can be seen that the effect of graphene-acetylene monomer is the worst, and the removal rate of tetracycline is only 35% after 12 minutes of reaction. When cobalt nanoparticles are loaded on graphene-acetylene, the degradation effect of cobalt nanoparticles / graphene-acetylene nanocomposite catalyst on tetracycline is greatly improved, and the removal rate of tetracycline can be increased to more than 60% after 12 minutes of reaction. In particular, when the mass ratio of cobalt nanoparticles to graphene-acetylene is 2:5, the corresponding cobalt nanoparticles / graphene-acetylene nanocomposite catalyst has a removal rate of 98.57% for tetracycline within 12 minutes. This is because: graphene-acetylene as a carrier improves the dispersibility of cobalt nanoparticles, thereby exposing more active metal sites for persulfate activation and tetracycline degradation. However, the addition of too many cobalt nanoparticles inhibits the catalytic effect, because too many cobalt nanoparticles cannot be effectively anchored on the surface of graphene-acetylene, which leads to the agglomeration of nanoparticles and reduces the catalytic effect. Therefore, in the present invention, by optimizing the mass ratio of cobalt nanoparticles and graphite-alkyne in the cobalt nanoparticle / graphite-alkyne nanocomposite catalytic material to be 1-16:20, in particular, the mass ratio of the two is 1:6-10, the corresponding cobalt nanoparticle loading amount in the cobalt nanoparticle / graphite-alkyne nanocomposite catalytic material is moderate and the dispersion is better, the material has more excellent catalytic performance and a more stable structure, and can meet different application requirements.

[0051] In addition, after the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material prepared by the present invention is used for multiple times to activate persulfate and treat antibiotic wastewater, it can efficiently activate persulfate and efficiently remove antibiotics in the water body, showing very excellent stability. By repeatedly using the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material to treat antibiotic wastewater, the treatment cost of antibiotic wastewater can be significantly reduced, which is convenient for promotion and use.

[0052] It can be seen from the above results that, compared with the conventional method, the present invention creatively proposes a method for preparing a cobalt nanoparticle / graphite-alkyne nanocomposite catalytic material, which uses graphite-alkyne, cobalt salt, nitrogen, nitrogen-dimethylformamide and anhydrous ethanol as raw materials, and sequentially undergoes ultrasound, solvent thermal reaction and calcination to convert a low-cost, high-cobalt content precursor material into cobalt nanoparticles with small particle size and good dispersibility, and by means of the interaction between graphite-alkyne and cobalt nanoparticles, the cobalt nanoparticles can be firmly attached to the surface of graphite-alkyne, and the stability and catalytic performance of the cobalt nanoparticles are significantly increased, and finally a cobalt nanoparticle / graphite-alkyne nanocomposite catalytic material with large specific surface area, large number of active sites, high cobalt nanoparticle loading, good cobalt nanoparticle dispersibility, high catalytic activity and good stability is prepared, which is a new type of cobalt catalyst with excellent catalytic performance and stable structure, and when the composite catalytic material is used to activate persulfate, the persulfate can be efficiently activated under the joint action of graphite-alkyne and cobalt nanoparticles, and the constructed degradation system can efficiently degrade organic pollutants, has high use value and good application prospects. At the same time, the preparation method of the present invention also has the advantages of simple process, convenient operation, mild reaction conditions, low cost, green and environmental protection, etc., and can be used for large-scale preparation and is convenient for industrial utilization.

[0053] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material, characterized in that: The following steps are involved: S1. Obtaining graphene; S2, mixing the graphene-acetylene, cobalt salt, nitrogen, nitrogen-dimethylformamide and anhydrous ethanol obtained in step S1, and performing ultrasonication to obtain a mixed solution; S3, performing a solvothermal reaction on the mixed solution obtained in step S2 to obtain a precursor material; S4, calcining the precursor material obtained in step S3 to obtain cobalt nanoparticles / graphite-acetylene nanocomposite catalytic material.

2. The preparation method according to claim 1, characterized in that: In step S2, the mass ratio of graphene to cobalt salt is 1:1-16.

3. The preparation method according to claim 2, characterized in that In step S2, the cobalt salt is cobalt chloride; the ratio of graphene-acetylene to nitrogen and nitrogen-dimethylformamide is 0.1 g:30 mL; the ratio of graphene-acetylene to anhydrous ethanol is 0.1 g:30 mL; and the ultrasonic time is 30 min.

4. The preparation method according to any one of claims 1 to 3, characterized in that In step S1, the method for preparing graphene-acetylene comprises the following steps: S1-1, mixing benzene and anhydrous ethanol, adding calcium carbide powder to obtain a dispersion; the ratio of the calcium carbide powder, benzene and anhydrous ethanol is 10 g: 2 mL: 35 mL; S1-2, adding the dispersion obtained in step S1-1 and stainless steel beads into a stainless steel ball mill, evacuating the mixture, reacting in a planetary ball mill, washing, and drying; during the reaction, the rotation speed of the planetary ball mill is controlled to be 600 rpm; the reaction time is 24 h; the washing is performed by washing with nitric acid and glacial acetic acid 3 to 5 times respectively; the drying is performed under vacuum conditions; the drying temperature is 60°C, and the drying time is 12 to 24 h; S1-3, annealing the material dried in step S1-2 to obtain graphene; the heating rate during the annealing process is 5°C / min; the annealing temperature is 260°C; and the annealing time is 2 h.

5. The preparation method according to any one of claims 1 to 3, characterized in that: In step S3, the temperature of the solvothermal reaction is 140°C; the time of the solvothermal reaction is 24 hours; after the solvothermal reaction is completed, the following treatment is also included: washing the product after the solvothermal reaction with anhydrous ethanol for 3 to 5 times, and drying it under vacuum conditions at a temperature of 60°C for 12 hours to 24 hours to obtain a precursor material; In step S4, the calcination is carried out under a nitrogen atmosphere; the calcination is firstly heated to 450°C at a heating rate of 5°C / min, calcined for 2h, then continued to heat to 700°C, calcined for 1h, to obtain a cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material.

6. A cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material comprises graphite-yne, on which cobalt nanoparticles are anchored; the mass ratio of cobalt nanoparticles to graphite-yne ​​in the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material is 1 to 16:

20.

7. The cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material according to claim 6, characterized in that: The mass ratio of cobalt nanoparticles to graphite-yne ​​in the cobalt nanoparticle / graphite-yne ​​nanocomposite catalytic material is 1-6:

20.

8. Use of the cobalt nanoparticle / graphite-acetylene nanocomposite catalytic material as claimed in claim 6 or 7 as a catalyst for activating persulfate in treating organic pollutant wastewater.

9. The use according to claim 8, characterized in that: The following steps are involved: Cobalt nanoparticles / graphite-alkyne nanocomposite catalytic materials and organic pollutant wastewater are mixed, and persulfate is added to carry out a Fenton-like catalytic reaction to complete the degradation of organic pollutants in the wastewater; the addition amount of the cobalt nanoparticles / graphite-alkyne nanocomposite catalytic materials is 0.05g to 0.2g per liter of organic pollutant wastewater; the addition amount of the persulfate is 0.1g to 0.5g per liter of organic pollutant wastewater.

10. The use according to claim 9, characterized in that The persulfate is peroxymonosulfate; the organic pollutants in the organic pollutant wastewater are antibiotics; the initial concentration of the organic pollutants in the organic pollutant wastewater is ≤10 mg / L; the antibiotic is tetracycline; and the time of the Fenton-like catalytic reaction is 6 min to 15 min.

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