A method for degrading bisphenol a using monatomic and atomic cluster manganese-based catalysts

Abstract

The application discloses a method for degrading bisphenol A by using monatomic and atomic cluster manganese-based catalysts, and belongs to the technical field of environmental remediation. The method comprises the following steps: adding monatomic and atomic cluster manganese-based catalysts into wastewater containing bisphenol A to establish adsorption and desorption equilibrium; then adding persulfate oxidants to cause Fenton-like degradation reaction; and finally recovering monatomic and atomic cluster manganese-based catalysts in the solution after the reaction is completed, so as to realize degradation and removal of bisphenol A. The monatomic and atomic cluster manganese-based catalysts comprise a carrier and active manganese species, the carrier is nitrogen-doped carbon, the active manganese species is manganese monatomic and manganese atomic cluster, the manganese atomic cluster is composed of multiple manganese monatomic, and the size of the manganese atomic cluster is 2-5 nm. In the monatomic and atomic cluster manganese-based catalysts, the loading amount of the active manganese species is 9-15 wt%. The method has good degradation effect on bisphenol A, can completely degrade 0.2 mM of bisphenol A reaction solution within 30 seconds, and has a wide pH adaptation range.

Description

Technical Field

[0001] This invention belongs to the field of environmental remediation technology, specifically relating to a method for degrading bisphenol A using single-atom and cluster manganese-based catalysts. Background Technology

[0002] Urban sewage and industrial wastewater commonly contain recalcitrant organic pollutants such as bisphenol A (BPA) and phenol. BPA, also known as bisphenol A propane, is widely used in the production of various polymer materials such as polycarbonate and epoxy resin, as well as in fine chemical products such as plasticizers, flame retardants, antioxidants, heat stabilizers, rubber antioxidants, pesticides, and coatings. Studies have shown that BPA has certain physiological toxicity, may cause endocrine system disorders, affect the reproductive system, and has some carcinogenic potential.

[0003] Currently, there are three main approaches to treating wastewater containing bisphenol A (BPA): biodegradation, physical absorption, and chemical remediation. Advanced oxidation processes based on persulfate activation are among the ideal solutions for eliminating phenolic pollutants in water. Among numerous heterogeneous catalysts for activating persulfate, single-atom catalysts have advantages such as good economic efficiency, excellent activity, and well-defined catalytic sites, and are attracting increasing attention. Cheng Chong et al. from the Free University of Berlin, Germany, synthesized a series of MN catalysts with similar structures and physicochemical properties. x -C-type single-atom catalysts (denoted as M-SACs, M = Mn, Fe, Co, Ni, Cu) revealed the PMS catalytic activity trend of common transition metal M-SACs experimentally and theoretically: Fe-SAC > Co-SAC > Mn-SAC > Ni-SAC > Cu-SAC. Iron-based single-atom catalysts showed the best catalytic activity in this system (Gao, Y., Wu, T., Yang, C., Ma, C., Zhao, Z., Wu, Z., Cao, S., Geng, W., Wang, Y., Yao, Y., Zhang, Y. and Cheng, C. (2021), Activity Trends and Mechanisms in Peroxymonosulfate-Assisted Catalytic Production of Singlet Oxygen over Atomic Metal-NC). Catalysts. Angew. Chem. Int. Ed. https: / / doi.org / 10.1002 / anie.202109530).

[0004] However, single-atom catalysts still have some shortcomings: on the one hand, due to thermodynamic instability, metal single atoms are prone to agglomeration during the preparation process, making it difficult for the metal loading of single-atom catalysts to exceed 5.0 wt%, thus limiting the continuous improvement of their activity; on the other hand, the active sites of single-atom catalysts are of a single form (usually MN). x The lack of diverse catalytic capabilities (such as oxidative cleavage of intramolecular C-C or CH bonds in pollutant molecules) results in poor activity of single-atom catalysts in synergistic degradation reactions. Chinese patent document CN110681396A discloses a method for the rapid degradation of bisphenol A in water. This invention synthesizes trimetallic spinel-type ferrite nanoparticles via chemical coprecipitation, achieving complete degradation of bisphenol A in water through adsorption and Fenton-like reaction processes. However, the nanoparticles are relatively large, and their catalytic activity needs further improvement.

[0005] Therefore, in order to address the problems of low metal loading and single active sites in single-atom catalysts, as well as the large size of metal nanoparticles and the need for further improvement in catalytic activity, it is urgent to develop a multiphase single-atom catalyst for efficient catalytic oxidation and degradation of bisphenol A. Summary of the Invention

[0006] This invention provides a method for degrading bisphenol A using single-atom and cluster manganese-based catalysts, which has good degradation effect on bisphenol A and a wide pH range adaptability.

[0007] The specific technical solution adopted is as follows:

[0008] A method for degrading bisphenol A using single-atom and cluster manganese-based catalysts, comprising:

[0009] (1) Add single-atom and cluster manganese-based catalysts to wastewater containing bisphenol A to establish adsorption-desorption equilibrium;

[0010] (2) Add persulfate oxidant to the system in step (1) to carry out Fenton-like degradation reaction. After the reaction is completed, recover the single-atom and cluster manganese-based catalyst in the solution to achieve the degradation and removal of bisphenol A.

[0011] The single-atom and cluster manganese-based catalysts include a support and active manganese species. The support is nitrogen-doped carbon, and the active manganese species are manganese single atoms and manganese clusters. The manganese clusters are composed of multiple manganese single atoms, and the size of the manganese clusters is 2-5 nm.

[0012] In the aforementioned single-atom and cluster manganese-based catalysts, the loading of active manganese species is 9-15 wt%.

[0013] This invention integrates manganese single atoms and manganese clusters to construct a multiphase single-atom-like catalyst for the degradation of bisphenol A. Compared to single atoms, atomic clusters exhibit greater stability and tunability in their geometry and electronic structure, and show more significant catalytic performance compared to larger metal nanoparticles. This invention leverages the unique interatomic interactions of the "manganese single atom + manganese cluster" combination to form a unique electronic structure distribution, providing diverse active sites in a Fenton-like reaction, thereby optimizing the reaction pathway and synergistically catalyzing the reaction to achieve rapid degradation of bisphenol A in wastewater. Under the action of single-atom and cluster manganese-based catalysts, the complete degradation of 0.4 mM bisphenol A solution can be achieved within 1 minute.

[0014] Preferably, the pH value of the bisphenol A-containing wastewater is 1-11, further preferably 2-10, and even more preferably 2, 6, or 10.

[0015] Preferably, in the bisphenol A-containing wastewater, the content of bisphenol A is 0.1-0.5 mM; and the amount of single-atom and cluster manganese-based catalyst added is 0.1-0.2 g / L.

[0016] Preferably, the persulfate is selected from potassium persulfate compound salt.

[0017] Specifically, in the aforementioned single-atom and cluster manganese-based catalysts, the number of manganese single atoms in the manganese cluster is less than 100, further, no more than 50, even further, 10-50, and still even further, 15-50.

[0018] Specifically, the preparation method of the single-atom and cluster manganese-based catalysts is as follows:

[0019] S01. Melamine, cyanuric acid, and tannic acid are added to water and dissolved to obtain solution A; an aqueous solution of manganese nitrate tetrahydrate is used as solution B; solution A and solution B are mixed while stirring to obtain a mixed solution; the mixed solution is stirred and the resulting solid is dried to obtain the manganese precursor.

[0020] S02 grinds the manganese precursor, anneals it at 400-800℃ for 1-5 hours in an inert gas atmosphere, and then cleans and dries it to obtain the single-atom and cluster manganese-based catalysts.

[0021] In step S01, the mass ratio of cyanuric acid, melamine, tannic acid and manganese nitrate tetrahydrate is 5:5:0.25-2:1.25-5, and the mass ratio of tannic acid and manganese nitrate tetrahydrate is 1:1-6.25.

[0022] This invention uses nitrogen-doped carbon as a support and tannic acid as a nitrogen source. Through high-temperature annealing, single-atom and cluster manganese are fixed on the nitrogen-doped carbon support to form single-atom and cluster manganese-based catalysts.

[0023] Preferably, the mass ratio of cyanuric acid, melamine, tannic acid and manganese nitrate tetrahydrate is 5:5:0.25-1:1.25-5, and most preferably it is 5:5:0.5:1.25.

[0024] Optionally, in step S02, the inert gas atmosphere is an argon atmosphere.

[0025] Preferably, the ground manganese precursor is annealed at 400-800℃ under an inert gas atmosphere at a heating rate of 1-15℃ / min.

[0026] More preferably, the ground manganese precursor is annealed at 600-800℃ under an inert gas atmosphere at a heating rate of 3-10℃ / min.

[0027] The preferred method is to anneal the ground manganese precursor at 600°C for 2 hours under an inert gas atmosphere at a heating rate of 10°C / min.

[0028] Optionally, in steps S01 and S02, the drying conditions are: 40-80℃, 24-60h;

[0029] This invention also provides the application of the single-atom and cluster manganese-based catalysts activating persulfate to form a Fenton-like system in the degradation of bisphenol A.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) This invention uses cyanuric acid as a precursor for manganese, and melamine and tannic acid as nitrogen sources to synthesize single-atom and cluster manganese-based catalysts, in which the product catalyst Mn a / c In NC-1.25 / 0.5, the loading of active manganese species in the catalyst is as high as 11.7 wt%. The preparation process of single-atom and cluster manganese-based catalysts is simple, the preparation time is short, the catalytic activity is strong, the metal loading is high, and the metal leakage rate is low. It can completely degrade 0.4 mM bisphenol A in 6 minutes, and under optimal conditions, it can completely degrade 0.2 mM bisphenol A reaction solution in 30 seconds, which surpasses the iron-based single-atom catalysts reported to date.

[0032] (2) In this invention, the manganese precursor forms an organic framework to fix the manganese sites through a dissolution and stirring reaction. Melamine and tannic acid are used as nitrogen sources to coordinate nitrogen through high-temperature calcination to form carbon-based materials of manganese single atoms and manganese atom clusters. The results show that manganese is dispersed in the form of single atoms and atom clusters through transmission electron microscopy, aberration electron microscopy and other means.

[0033] (3) The degradation of bisphenol A using a single-atom and cluster manganese-based catalyst to activate persulfate to form a Fenton-like system is an electron transfer reaction mechanism, not a free radical oxidation (such as SO42-). - The reaction pathways, including oxidation by OH or singlet oxygen, facilitate the selective degradation of organic pollutants and reduce the interference of complex water bodies on the system. When degrading bisphenol A, the system of this invention exhibits broad applicability to pH, with an applicable pH range of 1-11. Attached Figure Description

[0034] Figure 1 These are the X-ray diffraction patterns of the single-atom and cluster manganese-based catalysts prepared in Examples 1-6;

[0035] Figure 2 The X-ray diffraction patterns of the manganese-based catalysts prepared in Comparative Examples 2-3 are shown below.

[0036] Figure 3 These are scanning electron microscope images of the single-atom and cluster manganese-based catalysts prepared in Example 6;

[0037] Figure 4 These are high-angle annular dark-field scanning transmission electron microscope images of the single-atom and cluster manganese-based catalysts prepared in Example 6;

[0038] Figure 5 These are aberration-corrected high-angle annular dark-field scanning transmission electron microscope images of the single-atom and cluster manganese-based catalysts prepared in Example 6.

[0039] Figure 6 This is a graph showing the concentration changes of bisphenol A in the degradation of bisphenol A by the single-atom and cluster manganese-based catalysts prepared in Example 6;

[0040] Figure 7 This is a graph showing the changes in bisphenol A concentration at different pH levels for the single-atom and cluster manganese-based catalysts prepared in Example 6. Detailed Implementation

[0041] The present invention will be further illustrated below with reference to the embodiments and accompanying drawings. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0042] Example 1

[0043] Step 1: Take 5.0g of cyanuric acid (C3H3N3O3), 5.0g of melamine (C3H6N6), and 2.0g of tannic acid (C 76 H 52 O 46 Add the solution to 300 mL of deionized water and stir for 15 min to obtain solution A.

[0044] Step 2: Take 5.0g of manganese nitrate tetrahydrate (Mn(NO3)2·4H2O), add it to 100mL of deionized water, stir for 15min to obtain solution B;

[0045] Step 3: Add all of solution B to solution A while stirring and mixing to obtain solution C;

[0046] Step 4: Stir the mixture C at a speed of 1000 r / min for 9 hours.

[0047] Step 5: After the stirred solution C is allowed to stand for 12 hours, the precipitate is placed in a vacuum oven and dried at 60°C for 48 hours to obtain the manganese precursor.

[0048] Step 6: Grind the manganese precursor into powder (approximately 20 min), then place it in a tube furnace for annealing. After washing with deionized water and drying, the single-atom and cluster manganese-based catalysts are obtained. The annealing process involves raising the furnace temperature to 600°C at a rate of 10°C / min and holding it for 2 hours, followed by natural cooling. This single-atom and cluster manganese-based catalyst is labeled Mn. a / c -NC-5.0 / 2.0, X-ray diffraction pattern as follows Figure 1 As shown in the figure, graphite crystals are present but manganese oxides are not.

[0049] Bisphenol A degradation experiment: 100 mL of wastewater to be treated was added to an Erlenmeyer flask. The concentration of bisphenol A in the wastewater was 0.2 mM, the initial pH of the wastewater was 6.0, and the initial temperature was 25 °C. Then, 0.015 g of the single-atom and cluster manganese-based catalyst prepared in the above steps was added, and the mixture was sonicated for 10 min and shaken for 15 min to establish adsorption-desorption equilibrium. Then, 0.1 mL of a 1 mM potassium persulfate composite salt PMS solution was added to the above system to initiate the reaction to degrade and remove bisphenol A from the wastewater. After the reaction was completed, the single-atom and cluster manganese-based catalyst in the solution was recovered. The single-atom and cluster manganese-based catalyst prepared in this example can completely degrade 0.2 mM bisphenol A within 480 s.

[0050] Example 2

[0051] In this embodiment, the preparation method of the single-atom and cluster manganese-based catalysts differs from that in Example 1 only in that the amount of tannic acid used is 1g, while the other preparation methods and conditions are the same.

[0052] The single-atom and cluster manganese-based catalysts prepared in this embodiment are labeled Mn. a / c -NC-5.0 / 1.0, X-ray diffraction pattern as follows Figure 1 As shown in the figure, graphite crystals are present but manganese oxides are not.

[0053] In this embodiment, the bisphenol A degradation experiment method is the same as the degradation experiment scheme in Example 1, and the catalyst used is Mn. a / c -NC-5.0 / 1.0. Single-atom and cluster manganese-based catalysts Mn a / c -NC-5.0 / 1.0 can completely degrade 0.2mM bisphenol A within 180s.

[0054] Example 3

[0055] In this embodiment, the preparation method of the single-atom and cluster manganese-based catalysts differs from that in Example 1 only in that the amount of tannic acid used is 0.8g, while the other preparation methods and conditions are the same.

[0056] The single-atom and cluster manganese-based catalysts prepared in this embodiment are labeled Mn. a / c -NC-5.0 / 0.8, X-ray diffraction pattern as follows Figure 1 As shown in the figure, graphite crystals are present but manganese oxides are not.

[0057] In this embodiment, the bisphenol A degradation experiment method is the same as the degradation experiment scheme in Example 1, and the catalyst used is Mn. a / c -NC-5.0 / 0.8. Single-atom and cluster manganese-based catalysts Mn a / c -NC-5.0 / 0.8 can completely degrade 0.2mM bisphenol A within 120s.

[0058] Example 4

[0059] In this embodiment, the preparation method of the single-atom and cluster manganese-based catalysts differs from that in Example 1 only in that the amount of manganese nitrate tetrahydrate used is 3.0g, while the other preparation methods and conditions are the same.

[0060] The single-atom and cluster manganese-based catalysts prepared in this embodiment are labeled Mn. a / c -NC-3.0 / 2.0, X-ray diffraction pattern as follows Figure 1 As shown in the figure, graphite crystals are present but manganese oxides are not.

[0061] In this embodiment, the bisphenol A degradation experiment method is the same as the degradation experiment scheme in Example 1, and the catalyst used is Mn. a / c -NC-3.0 / 2.0. Single-atom and cluster manganese-based catalysts Mn a / c -NC-3.0 / 2.0 can completely degrade 0.2mM bisphenol A within 360s.

[0062] Example 5

[0063] In this embodiment, the preparation method of the single-atom and cluster manganese-based catalysts differs from that in Example 1 only in that the amount of manganese nitrate tetrahydrate used is 2.0g, while the other preparation methods and conditions are the same.

[0064] The single-atom and cluster manganese-based catalysts prepared in this embodiment are labeled Mn. a / c -NC-2.0 / 2.0, X-ray diffraction pattern as follows Figure 1 As shown in the figure, graphite crystals are present but manganese oxides are not.

[0065] In this embodiment, the bisphenol A degradation experiment method is the same as the degradation experiment scheme in Example 1, and the catalyst used is Mn. a / c -NC-2.0 / 2.0. Single-atom and cluster manganese-based catalysts Mn a / c -NC-2.0 / 2.0 can completely degrade 0.2mM bisphenol A within 300s.

[0066] Example 6

[0067] In this embodiment, the preparation method of the single-atom and cluster manganese-based catalysts differs from that in Example 1 only in that the amount of tannic acid used is 0.5g and the amount of manganese nitrate tetrahydrate used is 1.25g, while the other preparation methods and conditions are the same.

[0068] The single-atom and cluster manganese-based catalysts prepared in this embodiment are labeled Mn. a / c -NC-1.25 / 0.5, X-ray diffraction pattern as follows Figure 1 As shown in the figure, graphite crystals are present but manganese oxides are not.

[0069] Scanning electron microscope images of the single-atom and cluster manganese-based catalysts prepared in Example 6 are shown below. Figure 3 As shown in the figure, the single-atom and cluster manganese-based catalysts exist in a flocculent form; the high-angle annular dark-field scanning transmission electron microscope images of the single-atom and cluster manganese-based catalysts are as follows. Figure 4 As shown in the figure, it can be seen that the C, N, O, and Mn elements in the single-atom and cluster manganese-based catalysts prepared in Example 6 are relatively uniformly distributed in the catalyst; the aberration-corrected high-angle annular dark-field scanning transmission electron microscope images of the single-atom and cluster manganese-based catalysts are shown in the figure. Figure 5 As shown, the number of manganese atoms in both the single-atom and cluster manganese-based catalysts is less than 100 (the numbers indicate the number of single atoms in the corresponding clusters), and the size of the manganese clusters is 2-5 nm.

[0070] In this embodiment, the bisphenol A degradation experiment method is the same as the degradation experiment scheme in Example 1, and the catalyst used is Mn. a / c-NC-1.25 / 0.5. During the reaction, the concentration of bisphenol A in the reaction solution was tested. Specifically, 1 mL of the reaction solution was taken at the set time and filtered through a 220 nm filter membrane into a chromatographic bottle containing 0.5 mL of methanol solution. The concentration of bisphenol A in the reaction solution was tested using high-performance liquid chromatography (HPLC). The adsorption-degradation curve of bisphenol A in the water obtained by the test is shown below. Figure 6 As shown, during the first 25 minutes of adsorption-desorption process, approximately 1.04% of bisphenol A was adsorbed. After the degradation process began, bisphenol A in the water was 100% completely degraded within 30 seconds. Under the same conditions, similar iron-based catalysts require 30 minutes to degrade bisphenol A to 100%. Therefore, the manganese-based catalyst prepared in this example far surpasses similar iron-based catalysts.

[0071] Simultaneously, the changes in bisphenol A concentration due to the degradation of single-atom and cluster manganese-based catalysts prepared in this embodiment at different pH values ​​were tested, and the results are as follows: Figure 7 As shown, the single-atom and cluster manganese-based catalysts exhibit broad applicability to pH, with a pH range of 1-11.

[0072] Comparative Example 1

[0073] In this comparative example, the main focus is on comparing the iron-based catalysts under the same parameters as in Example 6. Under the same parameters, the iron-based catalysts (Li,Y.; Yang,T.; Qiu,S.; Lin,W.; Yan,J.; Fan,S.; Zhou,Q., Uniform N-coordinated single-atomic iron sites dispersed in porous carbon framework to activate PMS for efficient BPA degradation via high-valent iron-oxospecies. Chem. Eng.J. 2020, 389, 124382.) achieved 100% degradation of bisphenol A within 30 min, while the single-atom and cluster manganese-based catalysts prepared in Example 6 achieved 100% degradation of bisphenol A under the same parameters within 30 s.

[0074] Comparative Example 2

[0075] In this comparative example, the only difference between the preparation method of the manganese-based catalyst and that of Example 1 is that the amount of tannic acid used is 0.5g, while the other preparation methods and conditions are the same.

[0076] The manganese-based catalyst prepared in this comparative example is labeled as Mn. a / c -NC-5.0 / 0.5.

[0077] In this comparative example, the bisphenol A degradation experiment method is the same as the degradation experiment scheme in Example 1, and the manganese-based catalyst Mn a / c -NC-5.0 / 0.5 can completely degrade 0.2 mM bisphenol A within 60 s. Although this manganese-based catalyst achieves the same effect as similar iron-based catalysts, such as... Figure 2 The X-ray diffraction pattern results show that the manganese-based catalyst contains manganese oxides, but does not contain manganese clusters or graphite carbon crystals.

[0078] Comparative Example 3

[0079] In this comparative example, the preparation method of the manganese-based catalyst differs from that in Example 1 only in that the amount of tannic acid used is 0.25g, while the other preparation methods and conditions are the same.

[0080] The manganese-based catalyst prepared in this comparative example is labeled as Mn. a / c -NC-5.0 / 0.25.

[0081] In this comparative example, the bisphenol A degradation experiment method is the same as the degradation experiment scheme in Example 1, and the manganese-based catalyst Mn a / c -NC-5.0 / 0.25 can completely degrade 0.2mM bisphenol A within 60s. Although this manganese-based catalyst achieves the same effect as similar iron-based catalysts, such as... Figure 2 The X-ray diffraction pattern results show that the manganese-based catalyst contains manganese oxides, but does not contain manganese clusters or graphite carbon crystals.

[0082] Clearly, the degradation effects of Comparative Examples 2 and 3 on bisphenol A were worse than those in Example 6.

[0083] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for degrading bisphenol A using single-atom and cluster manganese-based catalysts, characterized in that, include: (1) Add single-atom and cluster manganese-based catalysts to wastewater containing bisphenol A to establish adsorption-desorption equilibrium; (2) Add persulfate oxidant to the system in step (1) to carry out Fenton-like degradation reaction. After the reaction is completed, recover the single-atom and cluster manganese-based catalyst in the solution to achieve the degradation and removal of bisphenol A. The single-atom and cluster manganese-based catalysts include a support and active manganese species. The support is nitrogen-doped carbon, and the active manganese species are manganese single atoms and manganese clusters. The manganese clusters are composed of multiple manganese single atoms, and the size of the manganese clusters is 2-5 nm. In the single-atom and cluster manganese-based catalysts described above, the loading of active manganese species is 9-15 wt%. The preparation method of the single-atom and cluster manganese-based catalysts is as follows: S01 Melamine, melamine, and tannic acid are dissolved in water to obtain solution A; an aqueous solution of manganese nitrate tetrahydrate is used as solution B; solution A and solution B are mixed while stirring to obtain a mixed solution. The resulting solid is dried to obtain a manganese precursor; the mass ratio of melamine, melamine, tannic acid, and manganese nitrate tetrahydrate is 5:5:0.25-2:1.25-5, and the mass ratio of tannic acid to manganese nitrate tetrahydrate is 1:1-6.

25. S02 After grinding the manganese precursor, it is annealed at 400-800℃ for 1-5 h in an inert gas atmosphere, and then cleaned and dried to obtain the single-atom and cluster manganese-based catalysts.

2. The method for degrading bisphenol A using single-atom and cluster manganese-based catalysts according to claim 1, characterized in that, The bisphenol A-containing wastewater has a pH value of 1-11 and a bisphenol A content of 0.1-0.5 mM; the amount of single-atom and cluster manganese-based catalysts added is 0.1-0.2 g / L.

3. The method for degrading bisphenol A using single-atom and cluster manganese-based catalysts according to claim 1, characterized in that, The persulfate mentioned is selected from potassium persulfate compound salt.

4. The method for degrading bisphenol A using single-atom and cluster manganese-based catalysts according to claim 1, characterized in that, The number of manganese atoms in a manganese cluster is less than 100.

5. The method for degrading bisphenol A using single-atom and cluster manganese-based catalysts according to claim 1, characterized in that, The mass ratio of cyanuric acid, melamine, tannic acid, and manganese nitrate tetrahydrate is 5:5:0.5:1.

25.

6. The method for degrading bisphenol A using single-atom and cluster manganese-based catalysts according to claim 1, characterized in that, In step S02, the inert gas atmosphere is an argon atmosphere.

7. The method for degrading bisphenol A using single-atom and cluster manganese-based catalysts according to claim 1, characterized in that, The ground manganese precursor was annealed at 400-800℃ under an inert gas atmosphere at a heating rate of 1-15℃ / min.

8. The method for degrading bisphenol A using single-atom and cluster manganese-based catalysts according to claim 1, characterized in that, The ground manganese precursor was annealed at 600-800℃ under an inert gas atmosphere at a heating rate of 3-10℃ / min.

9. The application of a single-atom and cluster manganese-based catalyst activating persulfate to form a Fenton-like system in the degradation of bisphenol A, characterized in that, The single-atom and cluster manganese-based catalysts include a support and active manganese species. The support is nitrogen-doped carbon, and the active manganese species are manganese single atoms and manganese clusters. The manganese clusters are composed of multiple manganese single atoms, and the size of the manganese clusters is 2-5 nm. In the single-atom and cluster manganese-based catalysts described above, the loading of active manganese species is 9-15 wt%. The preparation method of the single-atom and cluster manganese-based catalysts is as follows: S01 Melamine, melamine, and tannic acid are dissolved in water to obtain solution A; an aqueous solution of manganese nitrate tetrahydrate is used as solution B; solution A and solution B are mixed while stirring to obtain a mixed solution. The resulting solid is dried to obtain a manganese precursor; the mass ratio of melamine, melamine, tannic acid, and manganese nitrate tetrahydrate is 5:5:0.25-2:1.25-5, and the mass ratio of tannic acid to manganese nitrate tetrahydrate is 1:1-6.

25. S02 After grinding the manganese precursor, it is annealed at 400-800℃ for 1-5 h in an inert gas atmosphere, and then cleaned and dried to obtain the single-atom and cluster manganese-based catalysts.

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