Method for degrading antibiotics by using single-atom cobalt / hollow ceria catalytic material

Abstract

The application discloses a method for degrading antibiotics by using single-atom cobalt / hollow ceria catalytic material, which is used for degrading and treating antibiotic wastewater by taking single-atom cobalt / hollow ceria catalytic material as a catalyst for activating persulfate, and the single-atom cobalt / hollow ceria catalytic material used in the method comprises hollow ceria, on which single-atom cobalt is loaded. In the application, the single-atom cobalt / hollow ceria catalytic material has the advantages of high atom utilization rate, high atom loading capacity, excellent catalytic performance, strong stability and the like, and as a novel single-atom catalyst with excellent performance, the single-atom cobalt / hollow ceria catalytic material can efficiently activate persulfate without adding a promoter and can realize efficient degradation of antibiotics in wastewater, and has the advantages of simple process, convenient operation, high treatment efficiency, good removal effect, good adaptability, green environmental protection and the like, and has important significance for efficiently purifying antibiotics in the environment, high use value and good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional nanomaterials and water pollution control technology, and relates to a method for degrading antibiotics using single-atom cobalt / hollow cerium dioxide catalytic materials. Background Technology

[0002] Antibiotics are not only widely used in medicine and agriculture, but also enter the environment through human emissions and inadequate wastewater treatment. These antibiotics not only pose a potential threat to ecosystems, but may also promote the emergence of antibiotic-resistant bacteria through selective stress, thereby threatening public health. Therefore, developing efficient, green, and sustainable antibiotic degradation technologies has become one of the important research topics in the fields of environmental science and technology.

[0003] Compared with hydrogen peroxide, persulfate has the following advantages in advanced oxidation processes: (1) Persulfate is less dependent on pH and can be used in a wider range of aquatic environments, while the Fenton reaction of hydrogen peroxide is limited by acidity; (2) It can generate reactive oxygen species with higher oxidation potentials during activation; (3) Due to the asymmetry of its structure, the activation conditions for persulfate are usually more relaxed than those for hydrogen peroxide. Therefore, developing high-performance catalysts for activating persulfate is crucial.

[0004] Isolated metal atoms have been extensively studied in advanced persulfate oxidation due to their extremely high surface energy and activity. However, they spontaneously migrate and aggregate into clusters or nanoparticles, reducing the total energy. Therefore, to overcome the above technical problems, the strategy commonly used in the prior art is to load single atoms onto carbon materials, utilizing the covalent bond between single metal sites and carbon materials to break the limitations of traditional catalytic processes in terms of kinetics and catalytic activity. However, carbon materials as supports still have the following defects: (1) Carbon materials usually rely on defects (such as vacancies, heteroatom doping) to anchor single atoms, but the thermodynamic stability of these sites is limited. At high temperatures or during the reaction process, single atoms are prone to migrate and aggregate to form nanoparticles, leading to catalyst deactivation. (2) There are limitations in the anchoring method. The strength of metal-nitrogen bonds is usually weaker than that of metal-oxide bonds, and metal ion leaching may occur in strongly reducing or oxidizing environments. (3) When single atoms are loaded onto carbon materials, most of them are calcined at high temperatures to form mesoporous carbon, which greatly enhances the adsorption capacity of the catalytic material, thereby affecting its catalytic ability.

[0005] For the reasons mentioned above, existing researchers have proposed a method for preparing cobalt-cerium dioxide single-atom catalysts. First, cerium nitrate hexahydrate is calcined in a muffle furnace to obtain cerium dioxide, which is then mixed with a cerium salt solution and impregnated to obtain a catalyst precursor. Finally, the precursor is calcined in air to prepare the cobalt-cerium dioxide single-atom catalyst. However, this catalyst still suffers from drawbacks such as small specific surface area, few active sites, low atom utilization, poor catalytic activity, and poor stability. This results in poor activation of persulfates (such as PMS), making it difficult to construct efficient degradation systems. Consequently, additional promoters (such as bicarbonate) are required in its practical applications. In particular, this hinders the widespread application of cobalt-cerium dioxide single-atom catalysts in advanced oxidation processes.

[0006] Therefore, obtaining a novel single-atom cobalt / hollow cerium dioxide catalytic material with high atom utilization, high atom loading, excellent catalytic performance, and strong stability is of great significance for promoting the widespread application of advanced oxidation processes in antibiotic degradation and achieving effective removal of antibiotics from the environment. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for degrading antibiotics using single-atom cobalt / hollow cerium dioxide catalytic materials that is simple in process, convenient in operation, high in processing efficiency, good in removal effect, good in adaptability, and environmentally friendly.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A method for degrading antibiotics using a single-atom cobalt / hollow cerium dioxide catalytic material, wherein the method uses the single-atom cobalt / hollow cerium dioxide catalytic material as a catalyst for activating persulfate to degrade antibiotic wastewater; the single-atom cobalt / hollow cerium dioxide catalytic material comprises hollow cerium dioxide, wherein single-atom cobalt is loaded on the hollow cerium dioxide.

[0010] In a further improvement to the above method, the mass ratio of single-atom cobalt to hollow cerium dioxide in the single-atom cobalt / hollow cerium dioxide catalytic material is 1 to 5:50.

[0011] In a further improvement to the above method, the mass ratio of monatomic cobalt to hollow cerium dioxide in the monatomic cobalt / hollow cerium dioxide catalytic material is 2 to 3:50; and the hollow cerium dioxide has a hollow spherical structure.

[0012] A further improvement to the above method, the preparation method of hollow cerium dioxide includes the following steps:

[0013] (1) Mix trisodium citrate dihydrate, urea and water, add hydrogen peroxide solution and cerium catalyst, stir to obtain a mixed solution;

[0014] (2) The mixed solution was subjected to a hydrothermal reaction to obtain hollow cerium dioxide.

[0015] In a further improvement to the above method, in step (1), the mass ratio of trisodium citrate dihydrate, urea, and cerium catalyst is 55-65:500-520:515-530; the ratio of hydrogen peroxide solution to cerium catalyst is 0.5 mL-1 mL:515 mg-530 mg; the cerium catalyst is cerium nitrate hydrate; the mass fraction of hydrogen peroxide solution is 30%; the stirring speed is 500 rpm-800 rpm; and the stirring time is 1 h-2 h.

[0016] The above method is further improved in step (2), where the temperature of the hydrothermal reaction is 150℃~180℃ and the time of the hydrothermal reaction is 12h~20h; after the hydrothermal reaction is completed, the following treatment is also included: the hollow cerium dioxide slurry obtained after the hydrothermal reaction is washed with water and anhydrous ethanol, centrifuged at a speed of 8000rpm~10000rpm for 8min~10min, and the obtained solid product is dried under vacuum at a temperature of 40℃~80℃ for 480min~720min to obtain hollow cerium dioxide.

[0017] A further improvement to the above method, the preparation method of the single-atom cobalt / hollow cerium dioxide catalytic material includes the following steps:

[0018] S1. Obtain hollow cerium dioxide;

[0019] S2. Mix and stir the hollow cerium dioxide, ammonia, and cobalt salt obtained in step S1, and centrifuge to separate them to obtain a light yellow powder.

[0020] S3. In an argon atmosphere containing hydrogen, the pale yellow powder obtained in step S2 is calcined to obtain a single-atom cobalt / hollow cerium dioxide catalyst.

[0021] A further improvement to the above method, in step S2, the preparation method of the pale yellow powder includes the following steps:

[0022] S2-1. Hollow cerium dioxide is mixed with ammonia water and ultrasonically dispersed to obtain a hollow cerium dioxide dispersion. The ratio of hollow cerium dioxide to ammonia water is 50 mg: 10 mL to 20 mL; the mass fraction of ammonia water is 30%; and the ultrasonic dispersion time is 20 min to 30 min.

[0023] S2-2. Add cobalt salt to hollow cerium dioxide dispersion and stir to obtain precursor solution; the mass ratio of hollow cerium dioxide to cobalt salt in hollow cerium dioxide dispersion is 10:1 to 5; the cobalt salt is cobalt nitrate hexahydrate; the stirring time is 5 min to 20 min.

[0024] S2-3. The precursor solution was washed with water and anhydrous ethanol, and centrifuged at 8000 rpm to 10000 rpm for 8 min to 10 min. The resulting solid product was dried under vacuum at 40℃ to 80℃ for 480 min to 720 min to obtain a light yellow powder.

[0025] In a further improvement to the above method, in step S3, the volume percentage of hydrogen in the argon atmosphere containing hydrogen is 2% to 5%; the heating rate during the calcination process is 3℃ / min to 8℃ / min; the calcination temperature is 400℃ to 800℃; and the calcination time is 2h to 3h.

[0026] The above method is further improved by using single-atom cobalt / hollow cerium dioxide catalyst as a catalyst to activate persulfate for the degradation treatment of antibiotic wastewater, including the following steps: mixing single-atom cobalt / hollow cerium dioxide catalyst and antibiotic wastewater, adding persulfate to carry out a Fenton-like catalytic reaction, and completing the degradation of antibiotics in the wastewater.

[0027] In a further improvement to the above method, the amount of the single-atom cobalt / hollow cerium dioxide catalyst added is 0.05 g to 0.2 g per liter of antibiotic wastewater; the amount of persulfate added is 0.1 g to 0.5 g per liter of antibiotic wastewater; the persulfate is permonosulfate; the antibiotic in the antibiotic wastewater is at least one of sulfamethoxazole, levofloxacin, ciprofloxacin, and tetracycline; and the initial concentration of the antibiotic wastewater is ≤5 mg / L.

[0028] In a further improvement to the above method, the time for the Fenton-like catalytic reaction is 10 min to 15 min.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] (1) In view of the shortcomings of existing cobalt-cerium dioxide single-atom catalysts, such as small specific surface area, few active sites, low atomic utilization, poor catalytic activity and poor stability, and the resulting defects such as difficulty in efficiently activating persulfate, difficulty in efficiently degrading organic pollutants and poor reusability, this invention creatively proposes a method for degrading antibiotics using single-atom cobalt / hollow cerium dioxide catalyst material. The single-atom cobalt / hollow cerium dioxide catalyst material is used as a catalyst for activating persulfate to degrade antibiotic wastewater. The single-atom cobalt / hollow cerium dioxide catalyst material used includes hollow cerium dioxide, on which single-atom cobalt is loaded. In this invention, hollow cerium dioxide is used as the "active support" for single-atom cobalt. This not only enhances the loading capacity and stability of single-atom cobalt, but also allows it to directly participate in the reaction and form a strong synergistic effect with single-atom cobalt during the reaction. Therefore, by loading single-atom cobalt onto hollow cerium dioxide, the single-atom cobalt / hollow cerium dioxide catalytic material has the following advantages: (a1) Hollow cerium dioxide has a hollow structure, and its cavity can form a confined reaction environment, which can enrich reactant molecules, increase local concentration, and accelerate the reaction; (a2) The surface of hollow cerium dioxide has more abundant oxygen vacancies and defects that can act as "traps" to anchor single atoms, increasing the loading capacity of single-atom cobalt and thus improving catalytic activity. In particular, oxygen vacancies can act as electron buffers, dynamically adjusting electron density during PMS activation and promoting the generation of highly active free radicals. Simultaneously, the single-atom cobalt loaded on the surface of hollow cerium dioxide can act as a highly efficient electron switch, promoting the generation of Ce on the surface of hollow cerium dioxide. 4+ / Ce 3+ The cycling and generation and elimination of oxygen vacancies, especially from an electronic structure perspective, are unique to cerium dioxide (Ce). 4+ / Ce 3+Redox pairs can form strong electronic interactions with cobalt single atoms, significantly enhancing the electron transfer efficiency of the catalytic active center; (a3) ​​Utilizing the cavities and channels of hollow cerium dioxide, cobalt single atoms can be firmly anchored, thereby physically restricting the migration and aggregation of single-atom cobalt during the reaction process. Therefore, even if a single atom desorbs from the anchoring point, it is difficult to escape from the cavity and meet and aggregate into particles, thus greatly improving the thermal stability and cycle stability of the single-atom catalyst. This is a key strategy to solve the problem of easy sintering and deactivation of single-atom catalysts. More importantly, hollow cerium dioxide creates a unique "nanoreactor" effect for pollutant degradation through physical confinement and chemical microenvironment regulation. This enables the single-atom cobalt / hollow cerium dioxide catalytic material of the present invention to bring the following unexpected technical effects when used as a catalyst for activating persulfate to degrade antibiotic wastewater: (b1) From the perspective of spatial confinement, the hollow cavity can confine pollutant molecules within a limited space, greatly increasing the collision frequency between them and the active site. In particular, the local concentration of pollutant molecules in the hollow cavity can be 2-3 orders of magnitude higher than that in the solution, significantly improving the reaction kinetics. Meanwhile, the single-atom cobalt distribution on the cavity wall forms a uniform catalytic inner surface, ensuring that pollutants continuously contact the active sites during diffusion; (b2) From the perspective of mass transfer kinetics, the hollow structure creates a unique "internal and external synergistic" mass transfer pathway. Specifically, pollutant molecules and PMS can be transported simultaneously through the mesopores of the outer shell and the inner surface, allowing pollutant molecules and PMS to approach the active sites from both the inner and outer surfaces at the same time, greatly shortening the diffusion path. This multi-path diffusion mechanism breaks through the common diffusion limitation problem of traditional solid catalysts. Especially for macromolecular antibiotics, the larger pore size of the hollow structure avoids the problem of pore blockage. As can be seen, compared with conventional cobalt-cerium dioxide single-atom catalysts, the single-atom cobalt / hollow cerium dioxide catalytic material used in the method of this invention has advantages such as high atom utilization, high atom loading, excellent catalytic performance, and strong stability. As a novel single-atom catalyst with excellent performance, it can efficiently activate persulfate without the addition of promoters and achieve efficient degradation of antibiotics in wastewater. In particular, it can achieve efficient removal of antibiotics from wastewater under conditions of pH 3-11 and under the interference of different interfering substances, which greatly improves its practical applicability in advanced oxidation processes. It has the advantages of simple process, convenient operation, high treatment efficiency, good removal effect, good adaptability, and green environmental protection. It is of great significance for the efficient purification of antibiotics in the environment, has high use value, and good application prospects.

[0031] (2) In this invention, by optimizing the mass ratio of cobalt atoms to hollow cerium dioxide in the cobalt / hollow cerium dioxide catalytic material to 1–5:50, especially to 2–3:50, the aggregation of cobalt atoms can be effectively avoided, thereby exposing more active sites for catalytic reactions. Furthermore, in the catalytic material of this invention, insufficient cobalt loading can easily lead to insufficient active sites required for persulfate activation, while excessive cobalt loading will reduce electron generation and weaken Co… 3+ (III) Reduction to Co 2+ Its reducing activity.

[0032] (3) In the preparation method of hollow cerium dioxide used in this invention, urea and hydrogen peroxide are added. Urea, as a structure regulator, slowly decomposes into ammonia and carbon dioxide during the hydrothermal reaction. The ammonium ions formed by the ammonia dissolving in water gradually alkalinize the reaction, and the fine control of the pH gradient helps to form a uniform hollow structure. At the same time, the addition of hydrogen peroxide can regulate the Ce 3+ / Ce 4+ The conversion rate, along with changes in the local redox environment and supersaturation of the solution, is conducive to the stable formation of the hollow structure. It is evident that the combined action of urea and hydrogen peroxide leads to the formation of more abundant oxygen vacancies, which is more beneficial for subsequent strong Co-O-Ce interactions. Compared to existing hollow cerium dioxide, the hollow cerium dioxide prepared in this invention is key to improving the utilization rate, stability, and reaction efficiency of single-atom cobalt. By loading single-atom cobalt onto hollow cerium dioxide, a single-atom cobalt / hollow cerium dioxide catalytic material with high atom utilization, high atom loading, excellent catalytic performance, and strong stability can be obtained. Attached Figure Description

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0034] Figure 1 This is a scanning electron microscope image of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) prepared in Example 1 of the present invention.

[0035] Figure 2 This is a projection electron microscope image of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) prepared in Example 1 of the present invention.

[0036] Figure 3 The image shows the XRD patterns of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) and hollow cerium dioxide prepared in Example 1 of this invention.

[0037] Figure 4This is the energy dispersive X-ray spectral distribution of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) prepared in Example 1 of the present invention.

[0038] Figure 5 This is a comparison diagram showing the degradation effects of single-atom cobalt / hollow cerium dioxide catalytic materials (A1, A2, A3) and hollow cerium dioxide on sulfamethoxazole in Example 1 of the present invention.

[0039] Figure 6 This is a comparison chart showing the degradation effect of single-atom cobalt / hollow cerium dioxide catalyst (A1) on sulfamethoxazole under different pH conditions in Example 2 of the present invention.

[0040] Figure 7 This is a comparison chart showing the degradation effects of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) on different pollutants in Example 3 of the present invention.

[0041] Figure 8 This is a comparison chart showing the degradation effect of single-atom cobalt / hollow cerium dioxide catalytic material (A1) on sulfamethoxazole in the presence of different coexisting ions in Example 4 of the present invention.

[0042] Figure 9 This is a comparison diagram showing the degradation effect of single-atom cobalt / hollow cerium dioxide catalytic material (A1) on p-chlorophenol in Example 5 of the present invention.

[0043] Figure 10 This is a comparison chart of the normalized k-values ​​of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) in Example 5 of the present invention and existing catalytic materials. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0045] In the following embodiments 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.

[0046] Example 1

[0047] A method for degrading antibiotics using single-atom cobalt / hollow cerium dioxide catalytic material, specifically using single-atom cobalt / hollow cerium dioxide catalytic material as a catalyst for activating persulfate to degrade sulfamethoxazole wastewater, includes the following steps:

[0048] 50 mL of sulfamethoxazole solution with an initial pH of 6.8 and a concentration of 5 mg / L was added to a 150 mL beaker. 0.050 g of single-atom cobalt / hollow cerium dioxide catalyst (A1, A2, A3) was added separately. The mixture was stirred for 10 min in the dark to ensure uniform mixing and allow sulfamethoxazole to reach adsorption-desorption equilibrium on the material surface. 10 mg of persulfate was then added to initiate a Fenton-like catalytic reaction for 12 min, thus completing the degradation of sulfamethoxazole in the water.

[0049] Control group 1: Hollow cerium dioxide was used instead of single-atom cobalt / hollow cerium dioxide catalyst (A1), with other conditions remaining the same.

[0050] In this embodiment, the single-atom cobalt / hollow cerium dioxide catalytic material (A1) used includes hollow cerium dioxide with single-atom cobalt loaded on it; the mass ratio of single-atom cobalt to hollow cerium dioxide in the single-atom cobalt / hollow cerium dioxide catalytic material (A1) is 1:25. The hollow cerium dioxide has a hollow spherical structure.

[0051] In this embodiment, the preparation method of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) includes the following steps:

[0052] S1. Preparation of hollow cerium dioxide, specifically:

[0053] S1-1. Dissolve 58.5 mg of trisodium citrate dihydrate in 20 mL of deionized water to obtain a sodium citrate solution; dissolve 510.5 mg of urea in 85 mL of deionized water to obtain a urea solution; mix the two solutions, add 0.5 mL of 30% hydrogen peroxide solution and 524 mg of cerium nitrate hexahydrate while stirring at 800 rpm, then stir for 1 h, transfer the mixture to a 100 mL polytetrafluoroethylene-lined reactor, and hydrothermally react at 180 °C for 20 h to obtain a hollow cerium dioxide slurry.

[0054] S1-2. The hollow cerium dioxide slurry was washed three times each with water and anhydrous ethanol. The resulting mixed solution was centrifuged at 8000 rpm for 8 min and then vacuum dried at 60℃ for 720 min to obtain hollow cerium dioxide.

[0055] S2. Preparation of single-atom cobalt / hollow cerium dioxide catalytic materials

[0056] S2-1. Mix 50 mg of hollow cerium dioxide with 20 mL of 30% ammonia water and sonicate for 20 min to obtain a hollow cerium dioxide dispersion.

[0057] S2-2. Add 10 mg of cobalt nitrate hexahydrate to the hollow cerium dioxide dispersion and stir for 5 min to obtain the precursor solution.

[0058] S2-3. The precursor solution was washed with water and anhydrous ethanol three times each. The washed product was centrifuged at 8000 rpm for 8 min. The resulting solid product was dried under vacuum at 60℃ for 720 min to obtain a light yellow powder.

[0059] S2-4. Place the pale yellow powder in a tube furnace and calcine it to 600°C at a heating rate of 5°C / min under a mixed atmosphere of 5% hydrogen / 95% argon (the volume percentage of hydrogen in the mixed atmosphere is 5%). Hold the temperature for 3 hours to obtain a single-atom cobalt / hollow cerium dioxide catalyst.

[0060] In this embodiment, the single-atom cobalt / hollow cerium dioxide catalytic material (A2) used is basically the same as the single-atom cobalt / hollow cerium dioxide catalytic material (A1), the only difference being that the mass ratio of single-atom cobalt to hollow cerium dioxide in the single-atom cobalt / hollow cerium dioxide catalytic material (A2) is 1:50.

[0061] In this embodiment, the preparation method of the single-atom cobalt / hollow cerium dioxide catalytic material (A2) is basically the same as that of the single-atom cobalt / hollow cerium dioxide catalytic material (A1), except that the amount of cobalt nitrate hexahydrate used in the preparation method of the single-atom cobalt / hollow cerium dioxide catalytic material (A2) is 5 mg.

[0062] In this embodiment, the single-atom cobalt / hollow cerium dioxide catalytic material (A3) used is basically the same as the single-atom cobalt / hollow cerium dioxide catalytic material (A1), the only difference being that the mass ratio of single-atom cobalt to hollow cerium dioxide in the single-atom cobalt / hollow cerium dioxide catalytic material (A3) is 3:50.

[0063] In this embodiment, the preparation method of the single-atom cobalt / hollow cerium dioxide catalytic material (A3) is basically the same as that of the single-atom cobalt / hollow cerium dioxide catalytic material (A1), except that the amount of cobalt nitrate hexahydrate used in the preparation method of the single-atom cobalt / hollow cerium dioxide catalytic material (A3) is 15 mg.

[0064] Figure 1 This is a scanning electron microscope image of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) prepared in Example 1 of this invention. Figure 1 It can be seen that the single-atom cobalt / hollow cerium dioxide catalytic material (A1) has a spherical structure.

[0065] Figure 2This is a transmission electron microscope image of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) prepared in Example 1 of this invention. Figure 2 It can be seen that the single-atom cobalt / hollow cerium dioxide catalytic material (A1) has a hollow structure.

[0066] Figure 3 The images show the XRD patterns of the single-atom cobalt / hollow cerium dioxide catalytic material (Al) and hollow cerium dioxide prepared in Example 1 of this invention. Figure 3 It can be seen that the single-atom cobalt / hollow cerium dioxide catalytic material prepared by this invention only has the peak of the hollow cerium dioxide support and does not have the peak of metallic cobalt, proving that it is synthesized by a single atom.

[0067] Figure 3 This is the energy-dispersive X-ray spectral distribution of the single-atom cobalt / hollow cerium dioxide catalytic material (Al) prepared in Example 1 of this invention. Figure 4 It can be seen that the single-atom cobalt / hollow cerium dioxide catalytic material prepared by this invention contains cerium, oxygen and cobalt.

[0068] As can be seen from the above results, the single-atom cobalt / hollow cerium dioxide catalytic material of the present invention has been successfully prepared as a composite material.

[0069] During the reaction, 2 mL samples were taken at specified time points (e.g., 0, 2, 4, 6, 8, 10, and 12 min) and immediately filtered through a 0.22 μm organic phase membrane to separate the catalyst. The concentration of sulfamethoxazole in the solution was tested using high-performance liquid chromatography (HPLC), and the degradation efficiency of sulfamethoxazole by different materials was calculated. The results are as follows: Figure 5 As shown.

[0070] Figure 5 This is a comparison chart showing the degradation effects of single-atom cobalt / hollow cerium dioxide catalytic materials (A1, A2, A3) and hollow cerium dioxide on sulfamethoxazole in Example 1 of this invention. Figure 5It can be seen that the hollow cerium dioxide monomer has poor Fenton-like catalytic performance for sulfamethoxazole, with a removal rate of only 20% for tetracycline after 12 min of reaction. Unlike other methods, the single-atom cobalt / hollow cerium dioxide catalytic materials (A1, A2, A3) prepared in this invention exhibit removal rates of 100%, 94.9%, and 89.6% for sulfamethoxazole, respectively. This demonstrates that the catalytic performance of the single-atom cobalt / hollow cerium dioxide catalytic materials of this invention is far superior to that of hollow cerium dioxide monomers. Furthermore, the catalytic performance gradually increases and then decreases with increasing mass of cobalt nitrate hexahydrate. The single-atom cobalt / hollow cerium dioxide catalytic materials (A1, A2, A3) all showed removal rates of over 89% for sulfamethoxazole after 12 minutes of reaction. In particular, when the mass ratio of single-atom cobalt to hollow cerium dioxide is 1:25, the single-atom cobalt / hollow cerium dioxide catalytic material (A1) achieves a 100% removal rate for sulfamethoxazole after 12 minutes of reaction. This indicates that the single-atom cobalt / hollow cerium dioxide catalytic materials of this invention can efficiently remove antibiotics from water.

[0071] Example 2

[0072] A method for degrading antibiotics using a single-atom cobalt / hollow cerium dioxide catalytic material, specifically, using the single-atom cobalt / hollow cerium dioxide catalytic material (Al) prepared in Example 1 as a catalyst for activating persulfate, and applying it to degrade sulfamethoxazole wastewater under different pH conditions, includes the following steps:

[0073] Accurately weigh 5 mg of the single-atom cobalt / hollow cerium dioxide catalyst material (Al) prepared in Example 1, and add it to 50 mL of sulfamethoxazole aqueous solution with an initial concentration of 5 mg / L, respectively, and adjust the pH to 3, 5, 7, 9, and 11. Stir magnetically for 10 min in the dark to allow sulfamethoxazole to reach adsorption-desorption equilibrium on the catalyst surface. Subsequently, add 10 mg of permonosulfate (PMS) to each system to initiate the Fenton-like catalytic reaction.

[0074] During the reaction, 2 mL samples were taken at specified time points (e.g., 0, 2, 4, 6, 8, 10, and 12 min) and immediately filtered through a 0.22 μm organic phase membrane to separate the catalyst. The concentration of sulfamethoxazole in the solution was determined using high-performance liquid chromatography (HPLC), and the degradation efficiency of sulfamethoxazole by the single-atom cobalt / hollow cerium dioxide catalyst at different pH values ​​was calculated. The results are as follows: Figure 6 As shown.

[0075] Figure 6 This is a comparison chart showing the degradation effect of single-atom cobalt / hollow cerium dioxide catalyst (A1) on sulfamethoxazole under different pH conditions in Example 2 of this invention. Figure 6As can be seen, the single-atom cobalt / hollow cerium dioxide catalyst (Al) exhibits good removal performance across a wide pH range (3-11), indicating the broad practical applicability of the catalyst. This is mainly due to the confinement of the active sites, protecting them from pH interference. In contrast, traditional Fenton reactions and some current Fenton-like reactions cannot achieve efficient degradation of sulfamethoxazole at pH 7-11.

[0076] Example 3

[0077] A method for degrading antibiotics using a single-atom cobalt / hollow cerium dioxide catalytic material, specifically, using the single-atom cobalt / hollow cerium dioxide catalytic material (Al) prepared in Example 1 as a catalyst for activating persulfate, to degrade different pollutants, includes the following steps:

[0078] Accurately weigh 5 mg of single-atom cobalt / hollow cerium dioxide catalyst (A1) and add it to aqueous solutions of sulfamethoxazole, levofloxacin, ciprofloxacin, tetracycline, atrazine, and carbamazepine (each aqueous solution has a volume of 50 mL and an initial concentration of 5 mg / L). Stir magnetically for 10 min in the dark to allow sulfamethoxazole to reach adsorption-desorption equilibrium on the catalyst surface. Then, add 10 mg of permonosulfate (PMS) to each system to initiate a Fenton-like catalytic reaction.

[0079] During the reaction, 2 mL samples were taken at specified time points (e.g., 0, 2, 4, 6, 8, 10, and 12 min) and immediately filtered through a 0.22 μm organic phase membrane to separate the catalyst. The concentration of pollutants in the solution was tested using high-performance liquid chromatography (HPLC), and the degradation efficiency for different pollutants was calculated. The results are as follows: Figure 7 As shown.

[0080] Figure 7 This is a comparison chart showing the degradation effects of the single-atom cobalt / hollow cerium dioxide catalytic material (Al) on different pollutants in Example 3 of the present invention. From... Figure 7 As can be seen, the removal rates of sulfamethoxazole, levofloxacin, ciprofloxacin, tetracycline, atrazine, and carbamazepine by the single-atom cobalt / hollow cerium dioxide catalytic material (A1) are 100%, 100%, 97.7%, 100%, 96.1%, and 100%, respectively. This indicates that the single-atom cobalt / hollow cerium dioxide catalytic material of the present invention has a good removal effect on most pollutants and good adaptability.

[0081] Example 4

[0082] A method for degrading antibiotics using a single-atom cobalt / hollow cerium dioxide catalytic material, specifically, using the single-atom cobalt / hollow cerium dioxide catalytic material (Al) prepared in Example 1 as a catalyst for activating persulfate, and degrading sulfamethoxazole wastewater under different coexisting ion conditions, includes the following steps:

[0083] Accurately weigh 5 mg of the single-atom cobalt / hollow cerium dioxide catalyst material (A1) prepared in Example 1, and add it to 50 mL of sulfamethoxazole aqueous solution with an initial pH of 6.8 and an initial concentration of 5 mg / L. Add Cl-, a common water-borne anion, to the solution. - H2PO4 - SO4 2- and HCO3 2- The concentration of each catalyst was 3 mM. The mixture was magnetically stirred for 10 min in the dark to allow sulfamethoxazole to reach adsorption-desorption equilibrium on the catalyst surface. Subsequently, 10 mg of permonosulfate (PMS) was added to each system to initiate a Fenton-like catalytic reaction.

[0084] During the reaction, 2 mL samples were taken at specified time points (e.g., 0, 2, 4, 6, 8, 10, and 12 min) and immediately filtered through a 0.22 μm organic phase filter membrane to separate the catalyst. The concentration of sulfamethoxazole in the solution was determined using high-performance liquid chromatography (HPLC), and the degradation efficiency of sulfamethoxazole under different coexisting ions was calculated. The results are as follows: Figure 8 As shown.

[0085] Figure 8 This is a comparison chart showing the degradation effect of single-atom cobalt / hollow cerium dioxide catalyst (A1) on sulfamethoxazole in the presence of different coexisting ions in Example 4 of the present invention. Figure 8 As can be seen, the single-atom cobalt / hollow cerium dioxide catalytic material (Al) has a good anti-interference effect on most ions, which indicates that the single-atom cobalt / hollow cerium dioxide catalytic material of the present invention has a strong anti-interference ability, which is beneficial to its treatment of various organic pollutants in wastewater and broadens its practical application scope.

[0086] Example 5

[0087] The degradation effect of the single-atom cobalt / hollow cerium dioxide catalyst (Al) prepared in Example 1 on p-chlorophenol wastewater as an activated persulfate catalyst was investigated, including the following steps:

[0088] The single-atom cobalt / hollow cerium dioxide catalyst (Al) prepared in Example 1 was added to 30 mL of an aqueous solution of p-chlorophenol with an initial concentration of 5 mg / L at an addition rate of 0.2 g / L. The solution was magnetically stirred for 10 min in the dark to allow the p-chlorophenol to reach adsorption-desorption equilibrium on the catalyst surface. Subsequently, persulfate (PMS) was added to the system to bring the PMS concentration to 0.2 mM, initiating a Fenton-like catalytic reaction.

[0089] During the reaction, 2 mL samples were taken at specified time points (e.g., 0, 2, 4, 6, 8, 10, and 12 min) and immediately filtered through a 0.22 μm organic phase membrane to separate the catalyst. The concentration of p-chlorophenol in the solution was determined using high-performance liquid chromatography (HPLC), and the degradation efficiency of p-chlorophenol by the single-atom cobalt / hollow cerium dioxide catalyst was calculated. The results are as follows: Figure 9 As shown.

[0090] Figure 9 This is a comparison chart showing the degradation effect of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) on p-chlorophenol in Example 5 of the present invention. Figure 9 It is known that the degradation efficiency of single-atom cobalt / hollow cerium dioxide catalyst (A1) for p-chlorophenol is 70%; however, without the addition of bicarbonate ions, the degradation efficiency of existing cobalt-cerium dioxide single-atom catalysts is only 30%.

[0091] also, Figure 10 This is a comparison chart of the normalized k-values ​​of the single-atom cobalt / hollow cerium dioxide catalytic material (A1) in Example 5 of this invention and existing catalytic materials. From... Figure 10 As can be seen, the normalized k-value of the single-atom cobalt / hollow cerium dioxide catalyst (A1) is the highest, which indicates that the catalytic performance of the single-atom cobalt / hollow cerium dioxide catalyst (A1) is very good.

[0092] The results above show that, compared with conventional methods, the present invention utilizes single-atom cobalt / hollow cerium dioxide catalytic materials to degrade antibiotics. Using single-atom cobalt / hollow cerium dioxide catalytic materials with maximum atomic utilization, precise control of active centers, excellent catalytic performance, and strong stability as catalysts, this method can achieve highly efficient degradation of antibiotics with less catalyst usage. It has advantages such as low cost, high treatment efficiency, good removal effect, and environmental friendliness. It is of great significance for the effective removal of antibiotics from the environment, has high application value, and promising prospects.

[0093] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for degrading antibiotics using a single-atom cobalt / hollow ceria catalytic material, characterized in that, The method is to degrade and treat antibiotic wastewater by using single-atom cobalt / hollow ceria catalytic material as a catalyst for activating persulfate; the single-atom cobalt / hollow ceria catalytic material comprises hollow ceria, and single-atom cobalt is loaded on the hollow ceria and anchored in cavities and channels of the hollow ceria.

2. The method of claim 1, wherein, The mass ratio of single-atom cobalt to hollow ceria in the single-atom cobalt / hollow ceria catalytic material is 1-5:

50.

3. The method of claim 2, wherein, The mass ratio of single-atom cobalt to hollow ceria in the single-atom cobalt / hollow ceria catalytic material is 2-3:50; and the hollow ceria has a hollow spherical structure.

4. The method of claim 3, wherein, The preparation method of the hollow ceria comprises the following steps: (1) mixing trisodium citrate dihydrate, urea and water, adding hydrogen peroxide solution and cerium catalyst, and stirring to obtain a mixed solution; (2) performing hydrothermal reaction on the mixed solution to obtain hollow ceria.

5. The method of claim 4, wherein, In step (1), the mass ratio of trisodium citrate dihydrate, urea and cerium catalyst is 55-65:500-520:515-530; the ratio of hydrogen peroxide solution to cerium catalyst is 0.5 mL-1 mL:515 mg-530 mg; the cerium catalyst is cerium nitrate hydrate; the mass fraction of the hydrogen peroxide solution is 30%; the stirring speed is 500 rpm-800 rpm; and the stirring time is 1 h-2 h; In step (2), the hydrothermal reaction temperature is 150°C-180°C, and the hydrothermal reaction time is 12 h-20 h; after the hydrothermal reaction is completed, the following treatment is further included: washing the hollow ceria slurry obtained after the hydrothermal reaction is completed with water and anhydrous ethanol, centrifuging at a speed of 8000 rpm-10000 rpm for 8 min-10 min, drying the obtained solid product under vacuum at a temperature of 40°C-80°C for 480 min-720 min to obtain hollow ceria.

6. The method of claim 3, wherein, The preparation method of the single-atom cobalt / hollow ceria catalytic material comprises the following steps: S1, obtaining hollow ceria; S2, mixing and stirring the hollow ceria obtained in step S1, ammonia water and cobalt salt to perform reaction, and centrifuging to obtain a light yellow powder; S3, calcining the light yellow powder obtained in step S2 in an argon atmosphere containing hydrogen to obtain a single-atom cobalt / hollow ceria catalytic material.

7. The method of claim 6, wherein, In step S2, the preparation method of the light yellow powder comprises the following steps: S2-1, mixing hollow ceria and ammonia water, and ultrasonic dispersion to obtain a hollow ceria dispersion; the ratio of the hollow ceria to the ammonia water is 50 mg:10 mL-20 mL; the mass fraction of the ammonia water is 30%; and the ultrasonic dispersion time is 20 min-30 min; S2-2. Add cobalt salt to hollow cerium dioxide dispersion and stir to obtain precursor solution; the mass ratio of hollow cerium dioxide to cobalt salt in hollow cerium dioxide dispersion is 10:1 to 5; the cobalt salt is cobalt nitrate hexahydrate; the stirring time is 5 min to 20 min. S2-3. The precursor solution was washed with water and anhydrous ethanol, centrifuged at 8000 rpm to 10000 rpm for 8 min to 10 min, and the resulting solid product was dried under vacuum at 40℃ to 80℃ for 480 min to 720 min to obtain a light yellow powder. In step S3, the volume percentage of hydrogen in the argon atmosphere containing hydrogen is 2% to 5%; the heating rate during the calcination process is 3℃ / min to 8℃ / min; the calcination temperature is 400℃ to 800℃; and the calcination time is 2h to 3h.

8. The method according to any one of claims 1 to 7, characterized in that, The degradation treatment of antibiotic wastewater using single-atom cobalt / hollow cerium dioxide catalyst as an activated persulfate catalyst includes the following steps: mixing single-atom cobalt / hollow cerium dioxide catalyst with antibiotic wastewater, adding persulfate to carry out a Fenton-like catalytic reaction, and completing the degradation of antibiotics in the wastewater.

9. The method of claim 8, wherein, The amount of the single-atom cobalt / hollow cerium dioxide catalyst added is 0.05 g to 0.2 g per liter of antibiotic wastewater; the amount of persulfate added is 0.1 g to 0.5 g per liter of antibiotic wastewater; the persulfate is permonosulfate; the antibiotic in the antibiotic wastewater is at least one of sulfamethoxazole, levofloxacin, ciprofloxacin, and tetracycline; the initial concentration of the antibiotic wastewater is ≤5 mg / L.

10. The method of claim 9, wherein, The time for the Fenton-like catalytic reaction is 10 min to 15 min.

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