Catalyst for degradation of organic pollutants in water body by ozone, preparation method and application thereof

Abstract

The present application relates to a kind of catalyst for ozone degradation organic pollutants in water body and preparation method and application.The catalyst includes polymer carbon nitride base and cobalt monatomic atom supported on the polymer carbon nitride base;The cobalt monatomic atom and the polymer carbon nitride base form Co-N4 coordination structure.The technical problem to be solved is how to provide a kind of catalyst for ozone degradation organic pollutants in water body, the catalyst has ultra-high concentration Co monatomic atom active site and Co-N4 coordination structure, can direct activation ozone to generate Co-O3 non-radical active species, to realize the efficient, fast and stable degradation of organic pollutants in water body.

Description

Technical Field

[0001] This invention belongs to the field of environmental science and technology, and in particular relates to a catalyst for the ozone degradation of organic pollutants in water, its preparation method, and its application. Background Technology

[0002] The coexistence of microplastics, pathogenic microorganisms, and persistent water-soluble pollutants (such as pesticides, drug residues, and dyes) in water bodies poses a significant risk to ecosystems and public health. Existing methods such as physical adsorption, membrane separation, biodegradation, and traditional chemical oxidation have drawbacks, including incomplete degradation, high energy consumption, potential for secondary pollution, or limited applicability.

[0003] Ozone oxidation technology has a high redox potential (E°=2.07 V), and the final products are CO2, H2O, and O2, with a low risk of secondary pollution. However, without a catalyst, ozone mass transfer efficiency is low and the direct reaction rate is slow (10⁻³~10² s⁻¹). Existing heterogeneous ozone catalysts (such as Mn, Fe, Co, Cu-based oxides or single-atom materials) still have two major drawbacks: first, they have few active sites and weak ozone adsorption, leading to ozone escape; second, it is difficult to precisely control the generation pathway of reactive oxygen species (ROS). ·OH is easily quenched by background substances, and ¹O2 has high selectivity but limited degradation efficiency, making it impossible to produce optimal ROS for specific pollutants. Summary of the Invention

[0004] The main objective of this invention is to provide a catalyst for the ozone degradation of organic pollutants in water, its preparation method, and its application. The technical problem to be solved is how to provide a catalyst for the ozone degradation of organic pollutants in water, which has an ultra-high concentration of Co single-atom active sites and a Co-N4 coordination structure, capable of directionally activating ozone to generate Co-O3. Non-radical active species, thereby achieving efficient, rapid and stable degradation of organic pollutants in water.

[0005] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, a catalyst for the ozone degradation of organic pollutants in water is proposed. The catalyst comprises a polymer carbon nitride substrate and cobalt single atoms supported on the polymer carbon nitride substrate. The cobalt single atoms form a Co-N4 coordination structure with the polymer carbon nitride substrate.

[0006] In one possible implementation, the content of cobalt single atoms is 17% by weight, and the content of the polymer carbon nitride substrate is 83%.

[0007] In one possible implementation, the present invention also provides a method for preparing the above-mentioned catalyst for ozone degradation of organic pollutants in water, the preparation method comprising: S100. The polymer carbon nitride substrate is placed in a cobalt salt solution, then subjected to ultrasonic treatment and dried to obtain the precursor.

[0008] S200. The precursor is subjected to vacuum calcination at a temperature of 480–550°C for 1.5–2.5 hours.

[0009] In one possible implementation, the cobalt salt solution is selected from any one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt acetylacetonate. The concentration of the cobalt salt solution is 200 mmol / L.

[0010] In one possible implementation, step S100 involves preparing the polymer carbon nitride substrate by mixing melamine and dimelamine, calcining the mixture at 540–560°C for 2–4 hours, cooling, and then adding nitric acid for acid treatment to obtain the polymer carbon nitride substrate.

[0011] In one possible implementation, the molar ratio of melamine to dimelamine is 7:3.

[0012] In one possible implementation, the acid treatment method includes: mixing the cooled product with a 60-70 wt% nitric acid solution, stirring at room temperature for 2.5-3.5 h, ultrasonically dispersing for 0.8-1.2 h, filtering, discarding the supernatant, washing the precipitate with water 4-5 times, and drying to obtain a polymer carbon nitride substrate.

[0013] In one possible implementation, the amount of polymeric carbon nitride substrate added is 1 g. The amount of cobalt salt solution added is 20 mL.

[0014] In one possible implementation, the present invention also provides a method for the above-described catalyst for degrading organic pollutants in water using ozone, wherein the catalyst is added to the wastewater to be treated at a dosage of 1 g / L, stirred, and ozone is introduced to perform ozone catalytic oxidation treatment. The catalyst comprises a polymer carbon nitride substrate and cobalt single atoms supported on the polymer carbon nitride substrate. The cobalt single atoms form a Co-N4 coordination structure with the polymer carbon nitride substrate.

[0015] In one possible implementation, the ozone introduction rate is 10–100 mL / min. The temperature for ozone catalytic oxidation is 25–60 °C.

[0016] By employing the above technical solution, the catalyst, preparation method, and application for ozone degradation of organic pollutants in water proposed in this invention have at least the following advantages: 1. This application utilizes in-situ anchoring technology via negative pressure calcination to obtain ultra-high density uniformly loaded cobalt single atoms on a polymer carbon nitride substrate, with cobalt atoms forming a stable Co-N4 coordination structure with nitrogen atoms. This structure, on the one hand, significantly increases the number of active sites in the catalyst at the same dosage compared to conventional single-atom catalysts and nanoparticle catalysts, substantially improving the ozone activation efficiency per unit mass of catalyst. On the other hand, the Co-N4 covalent bonding effectively inhibits the dissolution of metal ions, enabling the catalyst to maintain high catalytic activity even after multiple cycles, demonstrating excellent structural stability.

[0017] 2. This application adopts the impregnation-negative pressure calcination method, which does not require the use of precious metal salts, nor does it require complex equipment such as atomic layer deposition or chemical vapor deposition. The raw materials are widely available, inexpensive, environmentally friendly, and can be mass-produced.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0019] Figure 1 The X-ray diffraction (XRD) spectra of the Co / PCN catalyst and the pure PCN substrate described in Example 1 of this invention are shown. Figure 2 The image shows a transmission electron microscope (TEM) image of the Co / PCN catalyst described in Example 1 of this invention. Figure 3 This is the elemental distribution diagram of the energy dispersive X-ray spectroscopy (EDS) of the Co / PCN catalyst described in Example 1 of this invention; Figure 4 This is a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) image of the Co / PCN catalyst described in Example 1 of this invention; Figure 5 The image shows the Co K-edge X-ray absorption near-edge structure (XANES) spectrum of the Co / PCN catalyst described in Example 1 of this invention. Figure 6 The image shows the Co K-edge extended X-ray absorption fine structure (EXAFS) spectrum of the Co / PCN catalyst described in Example 1 of this invention. Figure 7 The Co K-side EXAFS Fourier transform fitting curve of the Co / PCN catalyst described in Example 1 of this invention; Figure 8 This is a comparison chart of the degradation rate constants of phenol by Co / PCN catalysts with different Co loadings as described in Example 1 of the present invention; Figure 9This is a comparison chart of the ozone utilization rate and rate constant of phenol degradation by different catalysts of the present invention at different ozone flow rates. Figure 10 This is a graph showing the degradation rate of different types of soluble small molecule pollutants by the Co / PCN catalyst described in Example 1 of the present invention. Figure 11 This is a graph showing the degradation rate of different types of microplastic pollutants by the Co / PCN catalyst described in Example 1 of the present invention; Figure 12 This is a graph showing the changes in the catalytic performance of the Co / PCN catalyst described in Example 1 of this invention during multiple cyclic degradation experiments; Figure 13 The diagram shows the open-circuit voltage changes when ozone and pollutants are introduced sequentially using different catalysts as electrodes according to the present invention. Figure 14 This diagram illustrates the effect of introducing ozone and adding pollutants on the open-circuit voltage when different catalysts are used as electrodes in this invention. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a catalyst for ozone degradation of organic pollutants in water, its preparation method, and its application according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0021] This invention proposes a catalyst for the ozone degradation of organic pollutants in water. The catalyst comprises a polymeric carbon nitride substrate and cobalt single atoms supported on the polymeric carbon nitride substrate. The cobalt single atoms form a Co-N4 coordination structure with the polymeric carbon nitride substrate.

[0022] The catalyst disclosed in this application uses polymeric carbon nitride as a substrate, on which cobalt single atoms are loaded to form a Co-N4 coordination structure. This structure exhibits extremely strong adsorption and activation capabilities for ozone, and can directionally generate Co-O3. This is a non-radical reactive species. This species exhibits high oxidative activity and is not easily quenched by background substances such as carbonate and nitrate ions in the water, thus significantly improving ozone utilization and oxidation efficiency, thereby achieving rapid and efficient degradation of various pollutants (such as water-soluble organic molecules and microplastics). Experiments show that, under ozone flow rate conditions of 30 mL / min, the catalyst disclosed in this application can achieve a degradation rate of over 95% for pollutants in 50 mL of wastewater within 2 hours.

[0023] In one possible implementation, the content of cobalt single atoms is 17% by weight, and the content of the polymer carbon nitride substrate is 83%.

[0024] This application limits the content of cobalt single atoms and polymer carbon nitride substrate, which can prevent cobalt atoms from agglomerating while ensuring a high density of active sites and maintaining a uniform dispersion of single atoms.

[0025] In one possible implementation, the present invention also provides a method for preparing the above-mentioned catalyst for ozone degradation of organic pollutants in water, the preparation method comprising: S100. The polymer carbon nitride substrate is placed in a cobalt salt solution, then subjected to ultrasonic treatment and dried to obtain the precursor.

[0026] S200. The precursor is subjected to vacuum calcination at a temperature of 480–550°C for 1.5–2.5 hours.

[0027] In one possible implementation, the cobalt salt solution is selected from any one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt acetylacetonate. The concentration of the cobalt salt solution is 200 mmol / L.

[0028] In one possible implementation, step S100 involves preparing the polymer carbon nitride substrate by mixing melamine and dimelamine, calcining the mixture at 540–560°C for 2–4 hours, cooling, and then adding nitric acid for acid treatment to obtain the polymer carbon nitride substrate.

[0029] In one possible implementation, the molar ratio of melamine to dimelamine is 7:3.

[0030] In one possible implementation, the acid treatment method includes: mixing the cooled product with a 60-70 wt% nitric acid solution, stirring at room temperature for 2.5-3.5 h, ultrasonically dispersing for 0.8-1.2 h, filtering, discarding the supernatant, washing the precipitate with water 4-5 times, and drying to obtain a polymer carbon nitride substrate.

[0031] In one possible implementation, the amount of polymeric carbon nitride substrate added is 1 g. The amount of cobalt salt solution added is 20 mL.

[0032] This application discloses a method for preparing a catalyst for ozone degradation of organic pollutants in water. The preparation method employs an impregnation-negative pressure calcination method, and the specific steps include: S110. Preparation of polymer carbon nitride substrate: S111. Melamine and melamine are mixed in a molar ratio of 7:3, ground, and then placed in a corundum crucible after being ground evenly. The crucible is then placed in a muffle furnace and calcined at 550°C for 3 hours. After cooling to room temperature, a light yellow powdery intermediate product is obtained.

[0033] S112. Take 1g of intermediate product, grind it thoroughly, and then add it to 50mL of 65wt% nitric acid. Stir for 3h at room temperature and sonicate for 1h. Then centrifuge, remove the supernatant, wash with deionized water 5 times, and dry to obtain polymer carbon nitride substrate.

[0034] S120. Preparation of catalyst precursor: S121. Place 1g of polymer carbon nitride substrate in 20mL of a cobalt salt solution with a concentration of 200mmol / L (the cobalt salt solution can be any one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt acetylacetonate), then sonicate for 5h, and then dry at 80℃ to obtain a light pink solid powder precursor.

[0035] Preparation of S200 catalyst: The precursor was placed in a tube furnace. Argon gas was first introduced into the tube furnace at a rate of 30 mL / min to replace the air in the tube furnace. Then, the pressure inside the tube furnace was controlled at 0.01 bar using a vacuum pump. The pressure was maintained and calcined at 500 °C for 2 h to obtain a brown powder, which is the Co / PCN catalyst.

[0036] This invention utilizes an in-situ anchoring technique involving impregnation and negative pressure calcination to construct active centers with a Co-N4 coordination structure by loading ultra-high concentrations of Co single atoms onto a polymeric carbon nitride (PCN) substrate. This catalyst can efficiently activate ozone and directionally generate Co-O3. Non-radical reactive oxygen species (ROS) enable the rapid and efficient degradation of various pollutants, including water-soluble small organic molecules and microplastics. The preparation process of this invention is simple, requires no precious metal raw materials, and the resulting catalyst possesses advantages such as high catalytic activity, good stability, high ozone utilization, and wide applicability. Experimental results show that, under an ozone flow rate of 30 mL / min, this catalyst can achieve a pollutant degradation rate of over 95% in 50 mL of simulated wastewater within 2 hours.

[0037] In one possible implementation, the present invention also provides a method for the above-described catalyst for degrading organic pollutants in water using ozone, wherein the catalyst is added to the wastewater to be treated at a dosage of 1 g / L, stirred, and ozone is introduced to perform ozone catalytic oxidation treatment. The catalyst comprises a polymer carbon nitride substrate and cobalt single atoms supported on the polymer carbon nitride substrate. The cobalt single atoms form a Co-N4 coordination structure with the polymer carbon nitride substrate.

[0038] In one possible implementation, the ozone introduction rate is 10–100 mL / min. The temperature for ozone catalytic oxidation is 25–60 °C.

[0039] This application discloses a method for using the Co / PCN catalyst, as follows: A Co / PCN catalyst was added to 50 mL of wastewater containing organic pollutants at a dosage of 1 g / L, and the solution was ultrasonically treated for 30 min to disperse the catalyst. Ozone was then bubbled into the system with continuous stirring to perform ozone catalytic oxidation treatment, thereby degrading the organic pollutants in the wastewater. The ozone introduction rate was 10–100 mL / min, preferably 30 mL / min. The reaction temperature was 25–60 °C, preferably 60 °C.

[0040] Under conditions of ozone flow rate of 30 mL / min and temperature of 60 °C, the catalyst of this invention can achieve efficient degradation of organic pollutants in 50 mL of tap water, and maintain stable catalytic performance after multiple cycles. Specifically, it can degrade soluble small organic molecules (phenols, fuels, or antibiotics) at a concentration of 1 g / L within 30 min with a residual rate of less than 5%, and degrade microplastics (polyesters, polyamides, or polyolefins) at a concentration of 10 mg / L within 24 h with a residual rate of less than 5%.

[0041] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0042] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0043] Example 1 A method for preparing a catalyst for ozone degradation of organic pollutants in water, the method comprising: S110. Preparation of polymer carbon nitride substrate: S111. Melamine and melamine are mixed in a molar ratio of 7:3, ground, and then placed in a corundum crucible after being ground evenly. The crucible is then placed in a muffle furnace and calcined at 550°C for 3 hours. After cooling to room temperature, a light yellow powdery intermediate product is obtained.

[0044] S112. Take 1g of intermediate product, grind it thoroughly, and then add it to 50mL of 65wt% nitric acid. Stir for 3h at room temperature and sonicate for 1h. Then centrifuge, remove the supernatant, wash with deionized water 5 times, and dry to obtain polymer carbon nitride substrate.

[0045] S120. Preparation of catalyst precursor: S121. Place 1g of polymer carbon nitride substrate in 20mL of a cobalt salt solution with a concentration of 200mmol / L (the cobalt salt solution can be any one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt acetylacetonate), then sonicate for 5h, and then dry at 80℃ to obtain a light pink solid powder precursor.

[0046] Preparation of S200 catalyst: The precursor was placed in a tube furnace. Argon gas was first introduced into the tube furnace at a rate of 30 mL / min to replace the air in the tube furnace. Then, the pressure inside the tube furnace was controlled at 0.01 bar using a vacuum pump. The pressure was maintained and calcined at 500 °C for 2 h to obtain a brown powder, which is the Co / PCN catalyst.

[0047] Example 2 A method for preparing a catalyst for ozone degradation of organic pollutants in water, the method comprising: S110. Preparation of polymer carbon nitride substrate: S111. Melamine and melamine are mixed in a molar ratio of 7:3, ground, and then placed in a corundum crucible after being ground evenly. The crucible is then placed in a muffle furnace and calcined at 540°C for 4 hours. After cooling to room temperature, a light yellow powdery intermediate product is obtained.

[0048] S112. Take 1g of intermediate product, grind it thoroughly, and then add it to 50mL of 65wt% nitric acid. Stir for 2.5h at room temperature and sonicate for 1h. Then centrifuge, remove the supernatant, wash with deionized water 5 times, and dry to obtain polymer carbon nitride substrate.

[0049] S120. Preparation of catalyst precursor: S121. Place 1g of polymer carbon nitride substrate in 20mL of cobalt chloride solution with a concentration of 200mmol / L, then sonicate for 5h, and then dry at 80℃ to obtain a light pink solid powder precursor.

[0050] Preparation of S200 catalyst: The precursor was placed in a tube furnace. Argon gas was first introduced into the tube furnace at a rate of 30 mL / min to replace the air in the tube furnace. Then, the pressure inside the tube furnace was controlled at 0.01 bar using a vacuum pump. The pressure was maintained and calcined at 500 °C for 2 h to obtain a brown powder, which is the Co / PCN catalyst.

[0051] Example 3 A method for preparing a catalyst for ozone degradation of organic pollutants in water, the method comprising: S110. Preparation of polymer carbon nitride substrate: S111. Melamine and melamine are mixed in a molar ratio of 7:3, ground, and then placed in a corundum crucible after being ground evenly. The crucible is then placed in a muffle furnace and calcined at 560°C for 2 hours. After cooling to room temperature, a light yellow powdery intermediate product is obtained.

[0052] S112. Take 1g of intermediate product, grind it thoroughly, and then add it to 50mL of 65wt% nitric acid. Stir for 3.5h at room temperature and sonicate for 1h. Then centrifuge, remove the supernatant, wash with deionized water 5 times, and dry to obtain polymer carbon nitride substrate.

[0053] S120. Preparation of catalyst precursor: S121. Place 1g of polymer carbon nitride substrate in 20mL of cobalt nitrate with a concentration of 200mmol / L, then sonicate for 5h, and then dry at 80℃ to obtain a light pink solid powder precursor.

[0054] Preparation of S200 catalyst: The precursor was placed in a tube furnace. Argon gas was first introduced into the tube furnace at a rate of 30 mL / min to replace the air in the tube furnace. Then, the pressure inside the tube furnace was controlled at 0.01 bar using a vacuum pump. The pressure was maintained and calcined at 500 °C for 2 h to obtain a brown powder, which is the Co / PCN catalyst.

[0055] Example 3 A method for degrading water pollutants, comprising: S100. Weigh 1200 mg of the Co / PCN catalyst prepared in Example 1, and add a portion of the catalyst to 50 mL of wastewater to be treated at a concentration of 1 g / L.

[0056] S200. The above mixture is ultrasonically treated for 30 minutes to ensure uniform dispersion of the catalyst.

[0057] S300. Place the dispersed mixture in a reaction vessel, start stirring, and continuously bubble ozone into the system while stirring until the organic pollutants in the wastewater are completely degraded. The ozone bubbling rate is controlled at 30 mL / min, and the reaction temperature is controlled at 60℃.

[0058] Comparative Example 1 A method for degrading water pollutants, in which the catalyst of Comparative Example 1 is Co3O4, compared with Example 3.

[0059] Comparative Example 2 A method for degrading water pollutants, in which the catalyst in Comparative Example 2 is PCN, compared to Example 3.

[0060] Comparative Example 3 A method for degrading water pollutants, wherein the catalyst in Comparative Example 3 is Co2O3, compared with Example 3.

[0061] Comparative Example 4 A method for degrading water pollutants, wherein the catalyst in Comparative Example 4 is O3, compared with Example 3.

[0062] The Co / PCN catalyst prepared in Example 1 was characterized, and the results are as follows: pass Figure 1 The XRD patterns showed that the Co1 / PCN catalyst had similar diffraction peaks to the pure PCN substrate, and no characteristic diffraction peaks associated with elemental Co or cobalt oxides were observed, indicating that the cobalt species were highly dispersed on the PCN substrate. Figure 2 TEM images show that the Co / PCN catalyst exhibits a two-dimensional nanosheet structure. Figure 3 The EDS elemental distribution diagram shows that Co, C, and N are uniformly distributed on the catalyst surface. Figure 4 Numerous uniformly distributed bright spots were observed in the HAADF-STEM images, corresponding to individual Co atoms, confirming that Co exists on the PCN surface in single-atom form. Figures 5 to 7 Synchrotron radiation characterization results show that Co in Co1 / PCN mainly exists in a Co-N4 coordination structure, and no Co-Co metallic bonds were detected, further confirming the single-atom dispersion state of Co.

[0063] The catalytic activity of the catalyst was tested, and the results are as follows: pass Figure 8 It can be seen that the pollutant degradation rate is directly proportional to the Co atom loading, indicating that the Co atoms are utilized efficiently and that the ultra-high loading of Co single atoms can be fully utilized without site redundancy / deactivation. This shows that all Co active sites of the catalyst disclosed in this application effectively participate in the catalytic reaction, achieving maximum utilization of active sites, and thus maintaining excellent catalytic efficiency even at ultra-high loading density.

[0064] pass Figure 9 It can be seen that, under all ozone flow rate conditions, the ozone utilization rate and degradation rate constant of the Co / PCN catalyst disclosed in this application are significantly higher than those of the conventional catalysts in Comparative Examples 1, 2, 3, and 4. Furthermore, it can be seen that the performance of the Co / PCN catalyst reaches its peak at an ozone flow rate of 30 mL / min.

[0065] pass Figure 10 It can be seen that the Co / PCN catalyst disclosed in this application has a high degradation rate for typical persistent water-soluble organic pollutants in water, such as phenols, dyes, and antibiotics, with a residual rate of less than 5% in a short period of time. This proves that the catalyst has strong substrate adaptability and is not limited to a single pollutant, but is more suitable for the treatment of complex industrial wastewater and domestic sewage, and has a wide range of applications.

[0066] pass Figure 11 It can be seen that the Co / PCN catalyst disclosed in this application has good degradation efficiency for polyesters, polyamides, and polyolefins, which are mainstream environmentally difficult-to-degrade microplastics. Figure 11 It can be seen that, for recalcitrant microplastics, the catalyst has a degradation residual rate of less than 5% within a set time, indicating that the Co / PCN catalyst disclosed in this application can not only degrade persistent water-soluble organic pollutants in water, but also degrade microplastics in water, achieving dual degradation and further expanding the application scenarios of the catalyst.

[0067] pass Figure 12 It can be seen that after multiple cycle experiments, the degradation efficiency of the Co / PCN catalyst disclosed in this application does not decrease significantly and its performance remains stable. This further demonstrates that the coordination structure of Co-N4 is firmly bonded, Co single atoms are not easily detached or aggregated, and the catalyst has strong resistance to deactivation. This also shows that the catalyst disclosed in this application has strong stability and can be reused.

[0068] The catalytic mechanism of the catalyst was analyzed, and the results are as follows: pass Figure 13It can be seen that after ozone is introduced, the change in open-circuit voltage of the Co / PCN catalyst electrode disclosed in this application is much greater than that of conventional catalysts such as Comparative Examples 1, 2, 3 and 4. This indicates that the Co / PCN catalyst has a stronger ozone adsorption capacity, and ozone can be stably adsorbed on the active site with a longer residence time. It can overcome the defects of traditional catalysts, such as weak ozone adsorption and easy desorption and escape.

[0069] pass Figure 14 It can be seen that the Co / PCN catalyst disclosed in this application exhibits the strongest potential response in both the ozone activation and pollutant oxidation stages, indicating that the active substances it generates have a stronger oxidation capacity. Comparative Examples 1, 2, 3, and 4 show poorer performance, because traditional catalysts randomly generate ·OH... 1 O2、·O2 - It contains various free radicals, which are easily quenched by carbonate and nitrate ions in water, thus exhibiting poor performance. However, this catalyst directionally generates Co-O3. Non-radical active substances have high oxidation activity and excellent resistance to quenching, which enables Co / PCN catalysts to have stronger ozone adsorption capacity, and the active species generated after ozone adsorption have a stronger oxidation capacity for phenol.

[0070] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A catalyst for ozone degradation of organic pollutants in water, characterized in that, The catalyst comprises a polymeric carbon nitride substrate and cobalt single atoms supported on the polymeric carbon nitride substrate; the cobalt single atoms form a Co-N4 coordination structure with the polymeric carbon nitride substrate.

2. The catalyst for ozone degradation of organic pollutants in water according to claim 1, characterized in that, The content of cobalt single atoms is 17% by weight, and the content of the polymer carbon nitride substrate is 83%.

3. A method for preparing a catalyst for ozone degradation of organic pollutants in water as described in any one of claims 1 to 2, characterized in that, The preparation method includes: S100. The polymer carbon nitride substrate is placed in a cobalt salt solution, then subjected to ultrasonic treatment and dried to obtain the precursor; S200. The precursor is subjected to vacuum calcination at a temperature of 480–550°C for 1.5–2.5 hours.

4. The preparation method according to claim 3, characterized in that, The cobalt salt solution is selected from any one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt acetylacetonate; the concentration of the cobalt salt solution is 200 mmol / L.

5. The preparation method according to claim 3, characterized in that, In step S100, the preparation method of the polymer carbon nitride substrate includes: mixing melamine and dimelamine, mixing them evenly, calcining them at 540-560°C for 2-4 hours, cooling them, and then adding nitric acid for acid treatment to obtain the polymer carbon nitride substrate.

6. The preparation method according to claim 5, characterized in that, The molar ratio of melamine to dimelamine is 7:

3.

7. The preparation method according to claim 5, characterized in that, The acid treatment method includes: mixing the cooled product with a 60-70 wt% nitric acid solution, stirring at room temperature for 2.5-3.5 h, ultrasonically dispersing for 0.8-1.2 h, filtering, discarding the supernatant, washing the precipitate with water 4-5 times, and drying to obtain the polymer carbon nitride substrate.

8. The preparation method according to claim 3, characterized in that, The amount of the polymer carbon nitride substrate added is 1g; the amount of the cobalt salt solution added is 20mL.

9. A method for degrading water pollution using the catalyst for ozone degradation of organic pollutants in water as described in any one of claims 1 to 2, characterized in that, The catalyst was added to the wastewater to be treated at a dosage of 1 g / L, stirred, and ozone was introduced to carry out ozone catalytic oxidation treatment; the catalyst includes a polymer carbon nitride substrate and cobalt single atoms supported on the polymer carbon nitride substrate; the cobalt single atoms form a Co-N4 coordination structure with the polymer carbon nitride substrate.

10. The method for degrading water pollution according to claim 9, characterized in that, The ozone introduction rate is 10–100 mL / min; the ozone catalytic oxidation temperature is 25–60 °C.

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