A mo-co (oh) 2 nanosheet fenton-like catalyst, and a preparation method and application thereof

Abstract

The application discloses a Mo-Co(OH)2 nanosheet Fenton-like catalyst and a preparation method and application thereof, and the Fenton-like catalyst comprises Co(OH)2 nanosheets and monatomic Mo loaded on the Co(OH)2 nanosheets. The application provides a Mo-Co(OH)2 nanosheet Fenton-like catalyst and a preparation method and application thereof, and the Co(OH)2 nanosheet is used as a carrier of monatomic Mo, so that the Mo-Co(OH)2 nanosheet can effectively improve the catalytic activity and degradation efficiency of the Fenton-like catalyst.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials technology, and particularly relates to a Fenton-like catalyst of Mo-Co(OH)2 nanosheets, its preparation method and application. Background Technology

[0002] Antibiotics are secondary metabolites produced by microorganisms (bacteria, fungi, actinomycetes, etc.) or higher plants during their growth process. They possess antipathogenic or other activities and can interfere with or inhibit the survival of pathogenic microorganisms. In recent years, with the continuous improvement of science and technology and rapid economic development in my country, antibiotics have been widely used in medical treatment, aquaculture, and animal husbandry, and their demand is increasing year by year. Tetracycline antibiotics, as a broad-spectrum antibiotic, have strong antibacterial ability and are inexpensive. They are widely used not only for the prevention and treatment of human and animal diseases but also as animal feed to promote growth and development. Tetracycline antibiotics mainly include tetracycline, oxytetracycline, and chlortetracycline. Due to the large-scale use and disorderly discharge of these antibiotics, their residues are frequently detected in aquatic environments such as rivers, lakes, groundwater, and even oceans. Although the detected concentrations are very low, their bioaccumulation, persistence, and toxicity pose a potential threat to the ecological environment and human health. Therefore, the efficient removal of tetracycline antibiotics from water bodies is of great significance.

[0003] Currently, traditional methods for antibiotic removal include physical, chemical, and biochemical methods. Physical methods mainly rely on adsorption and membrane separation technologies. These technologies often use physical adsorption to trap antibiotics on the material surface, but this does not achieve complete removal. Biochemical methods are inefficient due to the long metabolic cycles of microorganisms, making it difficult to efficiently degrade antibiotics. In contrast, chemical methods react more rapidly with antibiotics in water and remove them more thoroughly, but they are prone to secondary pollution. Here, advanced oxidation processes can generate highly oxidizing active substances (such as ·OH and SO4) in the reaction system. - These active substances can decompose recalcitrant macromolecular organic matter into low-toxicity or non-toxic small molecules, and further mineralize them into H2O and CO2. Therefore, advanced oxidation technology is currently the most important and effective means of removing tetracycline antibiotics.

[0004] Existing advanced oxidation technologies mainly include ultrasonic oxidation, ozone (O3) oxidation, electrochemical oxidation, photocatalytic oxidation, and Fenton oxidation. Among these, persulfate-based Fenton advanced oxidation technologies (SR-AOPs) have become a research hotspot in the field of organic pollutant degradation due to their high degradation efficiency, wide applicable pH range, and ease of storage and transportation. Studies have found that persulfate-based Fenton advanced oxidation technologies can effectively remove various types of recalcitrant pollutants from the aquatic environment, such as volatile organic compounds, endocrine disruptors, drugs and their metabolites, cyanide toxins, and perfluorinated compounds. Therefore, it undoubtedly has great potential for the degradation of tetracycline antibiotics. However, due to the late start of research on this technology, many problems still need to be solved, such as: the selection, design, and construction of catalysts are not yet systematic; the mechanism of selective oxidation is unclear; and the reaction mechanism in the degradation process is not yet well understood.

[0005] Recently, single-atom catalysts (SACs) have attracted considerable attention due to their high atomic efficiency and unique electronic properties. Furthermore, Fenton-like advanced oxidation technologies based on single-atom catalysts have also seen rapid development due to their high reactivity and minimal catalyst usage. Currently developed single-atom catalysts typically involve supporting noble metal atoms on a substrate material (support), and these supported metal single-atom catalysts have proven to possess excellent catalytic performance. Molybdenum (Mo), as a common transition metal element, not only possesses advantages such as convenient preparation, low cost, stable performance, and low toxicity, but its single-atom Mo can also achieve a highly tunable d-orbital electronic structure through strong orbital hybridization with surrounding atoms, thus making it a suitable effective supporting metal for single-atom catalysts. Meanwhile, among various supports for single-atom catalysts, ultrathin two-dimensional (2D) nanosheets, due to their large specific surface area, numerous active sites, and excellent electron transport capabilities, have become a promising candidate for maximizing electrochemical performance in energy storage and conversion fields. However, since the porous structure constructed in ultrathin 2D nanosheets is inherently loose and prone to collapse or aggregation, it hinders electron transport, which greatly reduces its catalytic activity as a single-atom catalyst, and the actual application effect is not ideal. Summary of the Invention

[0006] Based on the above-mentioned technical problems, the present invention provides a Fenton-like catalyst of Mo-Co(OH)2 nanosheets, its preparation method and application. By using Co(OH)2 nanosheets as a support for single-atom Mo, the resulting Mo-Co(OH)2 nanosheets can effectively improve its catalytic activity and degradation efficiency as a Fenton-like catalyst.

[0007] The present invention proposes a Fenton-like catalyst based on Mo-Co(OH)2 nanosheets, wherein the Fenton-like catalyst comprises Co(OH)2 nanosheets and single-atom Mo supported on the Co(OH)2 nanosheets.

[0008] Preferably, the Co(OH)2 nanosheets are two-dimensional α-Co(OH)2 nanosheets with a thickness of 0.8-1 nm.

[0009] Preferably, the loading amount of the single-atom Mo on the Co(OH)2 nanosheet is 2-4 wt%.

[0010] The present invention also proposes a method for preparing the above-mentioned Mo-Co(OH)2 nanosheets Fenton-like catalyst, comprising: dissolving the triblock copolymer in an alcohol-water mixed solvent, adding cobalt salt, hexamethylenetetramine and ethylene glycol and stirring thoroughly, allowing it to stand for aging and then carrying out a hydrothermal reaction to obtain Co(OH)2 nanosheets; adding the Co(OH)2 nanosheets and molybdenum salt to an alcohol solvent and stirring thoroughly to obtain the Fenton-like catalyst.

[0011] Preferably, the triblock copolymer is at least one of polyether P123 or polyether F127; the cobalt salt is at least one of cobalt acetate, cobalt chloride, cobalt sulfate or cobalt nitrate; the molybdenum salt is at least one of molybdenum chloride, ammonium molybdate, sodium molybdate or molybdenum acetylacetonate; and the alcohol is ethanol.

[0012] Preferably, the molar ratio of the triblock copolymer, cobalt salt, hexamethylenetetramine, and ethylene glycol is 0.1-0.4:0.5-2:0.5-2:240-1000; the mass ratio of the Co(OH)₂ nanosheets to the molybdenum salt is 1-2:0.1-0.3.

[0013] Preferably, the volume ratio of the alcohol to the aqueous solvent is 15-65:1-4; and the concentration of the triblock copolymer in the alcohol-aqueous solvent is 8-145 mg / mL.

[0014] Preferably, the hydrothermal reaction is carried out at a temperature of 150-200°C for 1-3 hours.

[0015] Preferably, the reaction of the Co(OH)2 nanosheets and molybdenum salt in an alcohol solvent with thorough stirring specifically includes: ultrasonically dissolving the Co(OH)2 nanosheets in an alcohol solvent, adding an alcohol solution containing molybdenum salt, and stirring thoroughly for 10-20 hours to obtain a reaction solution containing the Fenton-like catalyst.

[0016] Preferably, the reaction solution is filtered using a 0.22 μm organic filter membrane to separate the Fenton-like catalyst.

[0017] This invention also proposes the application of the above-mentioned Fenton-like catalyst or the Fenton-like catalyst prepared by the above-mentioned preparation method in the degradation of tetracycline antibiotics.

[0018] Preferably, when degrading tetracycline antibiotics, the Fenton-like catalyst is combined with persulfate as a catalyst.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) The Fenton-like catalyst of Mo-Co(OH)2 nanosheets described in this invention uses Co(OH)2 with an ultrathin 2D nanosheet structure as a support. Its structure is formed by the collaborative self-assembly of oligomers (ethylene glycol) and polymer surfactant molecules (triblock copolymers) into a layered structure, which is then condensed, polymerized and crystallized into 2D metal hydroxide nanosheets with atomic thickness. The nanosheet structure formed by this self-assembly is not limited by the layered host material and can synthesize homogeneous nanomaterials in large quantities. Therefore, it can provide more anchorable vacancy sites for single Mo atoms (i.e., provide abundant single atom attachment sites). At the same time, the Co(OH)2 surface forms Mo-O, Mo-OH and Mo-Mo equivalent bonds with single Mo atoms, which helps electron transport and enhances catalytic performance.

[0021] (2) In the preparation of the Mo-Co(OH)2 nanosheet Fenton catalyst of the present invention, not only is the sheet structure of Co(OH)2 retained to ensure high catalytic activity, but the entire preparation method is simple to operate and the conditions are controllable.

[0022] (3) When the Fenton-like catalyst of the Mo-Co(OH)2 nanosheets described in this invention is applied to the degradation of tetracycline antibiotics, the introduction of stable low-valence Mo can significantly enhance the activity, especially the oxygen vacancies induced on the surface in the mixed metal oxide, which enhances the adsorption of O2. Therefore, by uniformly anchoring single-atom Mo on the metal hydroxide nanosheets, the electronic structure of the Mo sites can be precisely controlled, enhancing the electron transfer efficiency during the catalytic process, enhancing the activation rate of persulfate (PMS), and thus increasing the generation of active substances, ultimately achieving efficient degradation of tetracycline antibiotic pollutants. At the same time, the Fenton-like catalyst of the Mo-Co(OH)2 nanosheets contains hydroxyl groups, which enhance the adsorption performance of tetracycline, further improving the degradation rate and efficiency of tetracycline antibiotics. Attached Figure Description

[0023] Figure 1 Here is a SEM image of the Mo-Co(OH)2 nanosheets obtained in Example 1;

[0024] Figure 2 This is a TEM image of the Mo-Co(OH)2 nanosheets obtained in Example 1;

[0025] Figure 3 The image shows the HADDF-SETM diagram of the Mo-Co(OH)2 nanosheets obtained in Example 1.

[0026] Figure 4 The XRD patterns are comparison images of the Mo-Co(OH)2 nanosheets obtained in Example 1 and the Co(OH)2 nanosheets obtained in Comparative Example 1.

[0027] Figure 5 The above are FT-IR comparison images of Mo-Co(OH)2 nanosheets obtained in Example 1 and Co(OH)2 nanosheets obtained in Comparative Example 1.

[0028] Figure 6 The graph shows the degradation effect of different catalysts on tetracycline-containing water bodies as described in Example 1.

[0029] Figure 7 This is an experimental diagram showing the quenching effect of activated persulfate on tetracycline degradation by Mo-Co(OH)2 nanosheets obtained in Example 1;

[0030] Figure 8 The image shows the EPR curve of the activated persulfate degradation of tetracycline by the Mo-Co(OH)2 nanosheets obtained in Example 1. Detailed Implementation

[0031] The present invention will now be described in detail through specific embodiments. However, these embodiments are clearly provided for illustrative purposes and are not intended to limit the scope of the present invention.

[0032] Example 1

[0033] The Mo-Co(OH)2 nanosheets described in this embodiment can be used as Fenton-like catalysts, specifically including Co(OH)2 ultrathin nanosheets and single-atom Mo supported on Co(OH)2 ultrathin nanosheets.

[0034] The preparation methods of the above-mentioned Mo-Co(OH)2 nanosheets include:

[0035] 1.45 g (0.25 mmol) of polyether P123 was added to a mixed solvent composed of 80 mL of absolute ethanol and 2.5 mL of deionized water. After ultrasonic oscillation to form a clear solution, 0.30 g (1.2 mmol) of cobalt acetate tetrahydrate and 0.17 g (1.2 mmol) of hexamethylenetetramine (HMT) were added. After stirring and dissolving thoroughly, 35 g (0.56 mol) of ethylene glycol was added. After continuous stirring and dissolving, the obtained clear solution was allowed to stand and age, and then the clear solution was transferred to a high-temperature and high-pressure reaction kettle for hydrothermal reaction. The hydrothermal reaction temperature was 170 °C and the time was 2 h. After completion, it was centrifuged, washed alternately with deionized water and absolute ethanol, and vacuum dried at 60 °C overnight to obtain two-dimensional Co(OH)2 ultrathin nanosheets; 0.15 g of the two-dimensional Co(OH)2 ultrathin nanosheets was added to 100 mL of absolute ethanol. After ultrasonic oscillation to dissolve it thoroughly, 7.5 mL of a MoCl5 ethanol solution with a concentration of 2.5 g / L was quickly added dropwise. After stirring thoroughly for 12 h, it was filtered by a 0.22 μm organic filter membrane, washed with ethanol, and vacuum dried at 40 °C overnight to obtain the Mo-Co(OH)2 nanosheets.

[0036] Figure 1 Figure 4 is the SEM image of the Mo-Co(OH)2 nanosheets obtained in Example 1. Figure 2 Figure 5 is the TEM image of the Mo-Co(OH)2 nanosheets obtained in Example 1; as can be seen from Figure 1 and Figure 2 the Mo-Co(OH)2 nanosheets obtained in the example are in a flaky structure (0.8 - 1 nm), and show an α-Co(OH)2 crystal phase, with a structure similar to hydrotalcite, and its flaky structure has good conductivity. Figure 3 Figure 6 is the HADDF-STEM image of the Mo-Co(OH)2 nanosheets obtained in Example 1; as can be seen from Figure 3 in the Mo-Co(OH)2 nanosheets obtained in the example, single-atom Mo is successfully loaded on the surface of the Co(OH)2 nanosheets. According to the distribution of the bright spots, it is concluded that the single-atom Mo is evenly distributed and there is no agglomeration phenomenon.

[0037] Example 2

[0038] The Mo-Co(OH)2 nanosheets in this example can be used as a Fenton-like catalyst, specifically including Co(OH)2 ultrathin nanosheets and single-atom Mo loaded on the Co(OH)2 ultrathin nanosheets.

[0039] The preparation method of the above Mo-Co(OH)2 nanosheets includes:

[0040] 0.58 g (0.1 mmol) of polyether P123 was added to a mixed solvent consisting of 80 mL of anhydrous ethanol and 2.5 mL of deionized water. After ultrasonic oscillation to form a clear solution, 0.50 g (2 mmol) of cobalt acetate tetrahydrate and 0.28 g (2 mmol) of hexamethylenetetramine (HMT) were added and stirred thoroughly to dissolve. Then, 35 g (0.56 mol) of ethylene glycol was added and stirred to dissolve again. The resulting clear solution was allowed to stand for aging, and then transferred to a high-temperature and high-pressure reactor for hydrothermal reaction at a temperature of 150 °C. The reaction time was 3 hours. After the reaction, the nanosheets were centrifuged, washed alternately with deionized water and anhydrous ethanol, and then vacuum dried overnight at 60°C to obtain two-dimensional Co(OH)2 ultrathin nanosheets. 0.20 g of the two-dimensional Co(OH)2 ultrathin nanosheets were added to 100 mL of anhydrous ethanol and sonicated to dissolve them completely. Then, 5 mL of a 3 g / L MoCl5 ethanol solution was quickly added dropwise. After stirring thoroughly for 12 hours, the mixture was filtered through a 0.22 μm organic filter membrane, washed with ethanol, and vacuum dried overnight at 40°C to obtain the Mo-Co(OH)2 nanosheets.

[0041] Example 3

[0042] The Mo-Co(OH)2 nanosheets described in this embodiment can be used as Fenton-like catalysts, including Co(OH)2 ultrathin nanosheets and single-atom Mo supported on Co(OH)2 ultrathin nanosheets.

[0043] The preparation methods of the above-mentioned Mo-Co(OH)2 nanosheets include:

[0044] 2.32 g (0.4 mmol) of polyether P123 was added to a mixed solvent consisting of 80 mL of anhydrous ethanol and 2.5 mL of deionized water. After ultrasonic oscillation to form a clear solution, 0.12 g (0.5 mmol) of cobalt acetate tetrahydrate and 0.07 g (0.5 mmol) of hexamethylenetetramine (HMT) were added. After thorough stirring and dissolution, 35 g (0.56 mol) of ethylene glycol was added, and stirring was continued until dissolved. The resulting clear solution was allowed to stand for aging, and then transferred to a high-temperature and high-pressure reactor for hydrothermal reaction at a temperature of 20 °C. The mixture was centrifuged at 0℃ for 1 hour, washed alternately with deionized water and anhydrous ethanol, and then vacuum-dried overnight at 60℃ to obtain two-dimensional Co(OH)2 ultrathin nanosheets. 0.10 g of the two-dimensional Co(OH)2 ultrathin nanosheets were added to 100 mL of anhydrous ethanol and sonicated until fully dissolved. Then, 10 mL of a 2 g / L MoCl5 ethanol solution was rapidly added dropwise, and the mixture was stirred thoroughly for 12 hours. The mixture was then filtered through a 0.22 μm organic filter membrane, washed with ethanol, and vacuum-dried overnight at 40℃ to obtain the Mo-Co(OH)2 nanosheets.

[0045] Comparative Example 1

[0046] The Co(OH)2 nanosheets described in this comparative example can be used as Fenton-like catalysts, specifically including Co(OH)2 ultrathin nanosheets.

[0047] The preparation methods of the above-mentioned Co(OH)2 nanosheets include:

[0048] 1.45 g (0.25 mmol) of polyether P123 was added to a mixed solvent consisting of 80 mL of anhydrous ethanol and 2.5 mL of deionized water. After ultrasonic oscillation to form a clear solution, 0.30 g (1.2 mmol) of cobalt acetate tetrahydrate and 0.17 g (1.2 mmol) of hexamethylenetetramine (HMT) were added. After thorough stirring and dissolution, 35 g (0.56 mol) of ethylene glycol was added. After stirring and dissolution continued, the resulting clear solution was allowed to stand for aging. Then, the clear solution was transferred to a high-temperature and high-pressure reactor for hydrothermal reaction at 170 °C for 2 h. After the reaction, the solution was centrifuged, washed alternately with deionized water and anhydrous ethanol, and vacuum dried overnight at 60 °C to obtain two-dimensional Co(OH)2 ultrathin nanosheets, which are the Co(OH)2 nanosheets.

[0049] Figure 4 The image shows a comparison of the XRD patterns of the Mo-Co(OH)₂ nanosheets obtained in Example 1 and the Co(OH)₂ nanosheets obtained in Comparative Example 1, that is, a comparison of the XRD patterns of the Co(OH)₂ nanosheets before and after loading with single-atom Mo. Figure 4 It can be seen that Co(OH)2 nanosheets did not show any other characteristic peaks after being loaded with single-atom Mo, and Mo-Co(OH)2 nanosheets showed obvious peaks at 2θ = 34.01° and 2θ = 59.58°, which correspond to the (100) and (110) crystal planes of Co(OH)2 nanosheets, respectively. Figure 5 The image shows a FT-IR comparison of the Mo-Co(OH)₂ nanosheets obtained in Example 1 and the Co(OH)₂ nanosheets obtained in Comparative Example 1, that is, a FT-IR comparison of the Co(OH)₂ nanosheets before and after loading with single-atom Mo. Figure 5 It can be seen that no other characteristic peaks appeared after the Co(OH)2 nanosheets were loaded with single-atom Mo, and the main absorption band of the surface functional groups of Mo-Co(OH)2 nanosheets was at 3410 cm⁻¹. -1 The peak is the stretching vibration peak of -OH, and it is at 1300 cm⁻¹. -1 Up to 1600cm -1 The presence of multiple absorption bands is attributed to the aromatic functional group of C=C.

[0050] Comparative Example 2

[0051] The Mo-Co3O4 nanosheets described in this comparative example can serve as Fenton-like catalysts, specifically comprising Co3O4 nanosheets and single-atom Mo supported on Co3O4 nanosheets.

[0052] The preparation methods of the above-mentioned Mo-Co3O4 nanosheets include:

[0053] 1.45 g (0.25 mmol) of polyether P123 was added to a mixed solvent consisting of 40 mL of anhydrous ethanol and 2.5 mL of deionized water. After ultrasonic oscillation to form a clear solution, 0.30 g (1.2 mmol) of cobalt acetate tetrahydrate and 0.17 g (1.2 mmol) of hexamethylenetetramine (HMT) were added and stirred thoroughly to dissolve. Then, 35 g (0.56 mol) of ethylene glycol was added, and stirring was continued to dissolve. The resulting clear solution was allowed to stand for aging, and then transferred to a high-temperature and high-pressure reactor for hydrothermal reaction at 180 °C for 1 h. After the reaction, the solution was centrifuged, washed alternately with deionized water and anhydrous ethanol, and vacuum dried overnight at 60 °C. Two-dimensional Co(OH)₂ ultrathin nanosheets were obtained. 0.15 g of the two-dimensional Co(OH)₂ ultrathin nanosheets were added to 100 mL of anhydrous ethanol, and after ultrasonic oscillation to ensure complete dissolution, 7.5 mL of a 2.5 g / L MoCl₅ ethanol solution was rapidly added dropwise. After stirring thoroughly for 12 h, the mixture was filtered through a 0.22 μm organic filter membrane, washed with ethanol, vacuum dried overnight at 40 °C, and then calcined in a muffle furnace at 350 °C for 2 h to obtain the Mo-Co₃O₄ nanosheets. Alternatively, the two-dimensional Co(OH)₂ ultrathin nanosheets could be directly calcined in a muffle furnace at 350 °C for 2 h to obtain Co₃O₄ nanosheets.

[0054] Application Example 1

[0055] The degradation effects of the Mo-Co(OH)₂ nanosheets obtained in Example 1, the Co(OH)₂ nanosheets obtained in Comparative Example 1, the Co₃O₄ nanosheets obtained in Comparative Example 2, the Mo-Co₃O₄ nanosheets obtained in Comparative Example 2, the Mo-Co(OH)₂ nanosheets obtained in Example 1 + PMS, the Co(OH)₂ nanosheets obtained in Comparative Example 1 + PMS, the Co₃O₄ nanosheets obtained in Comparative Example 2 + PMS, and the Mo-Co₃O₄ nanosheets obtained in Comparative Example 2 + PMS were investigated. The specific experimental method was as follows: 10 mg of the Mo-Co(OH)₂ nanosheets obtained in Example 1, 10 mg of the Co(OH)₂ nanosheets obtained in Comparative Example 1, 10 mg of the Co₃O₄ nanosheets obtained in Comparative Example 2, 10 mg of the Mo-Co₃O₄ nanosheets obtained in Comparative Example 2, 10 mg of the Mo-Co(OH)₂ nanosheets obtained in Example 1 + 30 mg of PMS, and 10 mg of the Co(OH)₂ nanosheets obtained in Comparative Example 1 + 30 mg of PMS were used as catalysts. PMS, 10 mg of Co3O4 nanosheets obtained from Comparative Example 2 + 30 mg of PMS, and 10 mg of Mo-Co3O4 nanosheets obtained from Comparative Example 2 + 30 mg of PMS were dispersed in water samples containing 20 ppm tetracycline (V = 100 mL). The tetracycline concentration in the water samples was measured at time intervals of 0 min, 2 min, 5 min, 10 min, 20 min, and 30 min. The results are as follows: Figure 6 As shown.

[0056] Figure 6 The graph shows the degradation effect of different catalysts on tetracycline-containing water bodies as described in Example 1; Figure 6 It can be seen that, compared with the Co(OH)2 nanosheets obtained in Comparative Example 1, the Co3O4 nanosheets obtained in Comparative Example 2, and the Mo-Co3O4 nanosheets, the Mo-Co(OH)2 nanosheets obtained in Example 1 exhibit better adsorption performance; compared with the Co(OH)2 nanosheets obtained in Comparative Example 1, the Co3O4 nanosheets obtained in Comparative Example 2, and the Mo-Co3O4 nanosheets obtained in Example 1, when combined with PMS, achieve a 99% degradation capacity in 2 minutes, and the reaction rate is faster.

[0057] Figure 7 This is an experimental diagram illustrating the quenching effect of Mo-Co(OH)₂ nanosheets obtained in Example 1 on the degradation of tetracycline by activated persulfate. Figure 7It can be seen that, without the addition of any quenching agent, the degradation efficiency of tetracycline can reach 99% within 2 minutes. When 1M tert-butanol (TBA) is added, the degradation efficiency of tetracycline decreases to 95.8%, indicating that ·OH has virtually no effect in the degradation of tetracycline. When 1M anhydrous ethanol (ETOH) or 1mM L-histidine (L-His) is added, the degradation efficiency of tetracycline decreases to 69.5% and 70%, respectively, indicating that SO42-... - ·and 1 O2 plays a major role in the degradation of tetracycline.

[0058] Figure 8 This is an EPR diagram of the activation of persulfate to degrade tetracycline (TC) by Mo-Co(OH)₂ nanosheets obtained in Example 1. Figure 8 It can be seen that only when PMS is present is a weak DMPO-·OH signal detected in the system, indicating that PMS can self-decompose to produce a small amount of ·OH; when PMS and Mo-Co(OH)2 nanosheets are added to the water sample, the addition of DMPO captures the signal, which is fitted as the superposition of CH3· and ·OH signals, and the signal is significantly enhanced; when TEMP captures the signal, a... 1 The O2 signal indicates that there is also O2 in the reaction. 1 The presence of O2. Based on the combined results of free radical quenching and free radical capture experiments on this system, it can be concluded that SO42- is present during the activation of PMS by Mo-Co(OH)2. - ·、·OH、 1 O2 is present in all of them, including SO4. - ·and 1 O2 plays a key role in the degradation of tetracycline.

[0059] Application Example 2

[0060] Using the Mo-Co(OH)2 nanosheets + PMS obtained in Example 1 as a catalyst, the degradation behavior of chlortetracycline by the Mo-Co(OH)2 nanosheets + PMS obtained in Example 1 as a catalyst was studied.

[0061] The specific experimental method was as follows: 20 mg of Mo-Co(OH)2 nanosheets obtained in Example 1 were added to a prepared 20 ppm chlortetracycline solution (V = 100 mL), and 30 mg of PMS was added at the same time. The reaction was stirred for 30 min, and the degradation efficiency of chlortetracycline was measured to be 90%.

[0062] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. The application of a Fenton-like catalyst based on Mo-Co(OH)2 nanosheets in the degradation of tetracycline antibiotics, characterized in that, The Fenton-like catalyst comprises Co(OH)₂ nanosheets and single-atom Mo supported on the Co(OH)₂ nanosheets; The preparation method of the Fenton-like catalyst of Mo-Co(OH)2 nanosheets includes: dissolving the triblock copolymer in an alcohol-water mixed solvent, adding cobalt salt, hexamethylenetetramine and ethylene glycol, stirring thoroughly, allowing it to stand for aging, and then carrying out a hydrothermal reaction to obtain Co(OH)2 nanosheets; adding the Co(OH)2 nanosheets and molybdenum salt to an alcohol solvent and stirring thoroughly to obtain the Fenton-like catalyst.

2. The application of the Fenton-like catalyst of Mo-Co(OH)2 nanosheets according to claim 1 in the degradation of tetracycline antibiotics, characterized in that, The Co(OH)2 nanosheets are two-dimensional α-Co(OH)2 nanosheets with a thickness of 0.8-1 nm.

3. The application of the Fenton-like catalyst of Mo-Co(OH)₂ nanosheets according to claim 1 in the degradation of tetracycline antibiotics, characterized in that, The loading of the single-atom Mo on the Co(OH)2 nanosheet is 2-4 wt%.

4. The application of the Fenton-like catalyst of Mo-Co(OH)2 nanosheets according to claim 1 in the degradation of tetracycline antibiotics, characterized in that, The triblock copolymer is at least one of polyether P123 or polyether F127; the cobalt salt is at least one of cobalt acetate, cobalt chloride, cobalt sulfate or cobalt nitrate; the molybdenum salt is at least one of molybdenum chloride, ammonium molybdate, sodium molybdate or molybdenum acetylacetonate; and the alcohol is ethanol.

5. The application of the Fenton-like catalyst of Mo-Co(OH)₂ nanosheets according to claim 1 in the degradation of tetracycline antibiotics, characterized in that, The molar ratio of the triblock copolymer, cobalt salt, hexamethylenetetramine, and ethylene glycol is 0.1-0.4:0.5-2:0.5-2:240-1000; the mass ratio of the Co(OH)₂ nanosheets to the molybdenum salt is 1-2:0.1-0.

3. The volume ratio of the alcohol to the aqueous solvent is 15-65:1-4; the concentration of the triblock copolymer in the alcohol-aqueous solvent is 8-145 mg / mL.

6. The application of the Fenton-like catalyst of Mo-Co(OH)₂ nanosheets according to claim 1 in the degradation of tetracycline antibiotics, characterized in that, The hydrothermal reaction is carried out at a temperature of 150-200 ℃ for 1-3 h.

7. The application of the Fenton-like catalyst of Mo-Co(OH)₂ nanosheets according to claim 1 in the degradation of tetracycline antibiotics, characterized in that, The specific steps of adding the Co(OH)2 nanosheets and molybdenum salt to an alcohol solvent and stirring thoroughly include: ultrasonically dissolving the Co(OH)2 nanosheets in an alcohol solvent, adding an alcohol solution containing molybdenum salt, and stirring thoroughly for 10-20 hours to obtain a reaction solution containing the Fenton-like catalyst. The reaction solution was filtered using a 0.22 μm organic filter membrane to separate the Fenton-like catalyst.

8. The application of the Fenton-like catalyst of Mo-Co(OH)2 nanosheets according to claim 1 in the degradation of tetracycline antibiotics, characterized in that, When degrading tetracycline antibiotics, the Fenton-like catalyst is combined with persulfate as a catalyst.

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