Cobalt-manganese spinel compound PMS activator and preparation method and application thereof

Abstract

The invention discloses a cobalt-manganese spinel compound PMS activator and a preparation method and application thereof, and belongs to the technical field of oxidation technology and environmental catalysis. According to the activating agent, a cobalt source and a manganese source serve as precursors, precursor precipitates are prepared through a low-temperature coprecipitation method, and cobalt manganese oxide of a spinel structure is finally obtained through heat treatment, centrifugal washing, drying and calcination. The activator can show excellent catalytic performance in a PMS activated degradation organic pollutant system, and can be widely applied to removal of organic pollutants in the fields of industrial wastewater, domestic sewage, environmental restoration and the like. The method is simple in process, and the obtained product is high in catalytic activity and good in stability and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of oxidation technology and environmental catalysis technology, specifically relating to a cobalt-manganese spinel compound PMS activator, its preparation method and application. Background Technology

[0002] In recent years, peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) have attracted widespread attention in the water treatment field due to their high selectivity, mild reaction conditions, and broad-spectrum degradation capabilities for a variety of persistent organic pollutants. Under appropriate activation conditions, PMS can generate highly oxidizing reactive species, such as sulfate radicals, hydroxyl radicals, and high-valence metal intermediates. These reactive species exhibit excellent degradation performance on recalcitrant organic pollutants in water, such as antibiotics, dyes, and endocrine disruptors.

[0003] Catalytic activation is one of the key pathways to improve the efficiency of PMS reactions. Common activation methods include thermal activation, UV activation, electrochemical activation, and metal catalytic activation. Among these, metal oxide catalysts are widely used in PMS activation systems due to their ease of operation, high reaction efficiency, and strong recyclability. Currently reported PMS metal catalysts mainly include Fe-based (e.g., Fe3O4), Mn-based (e.g., MnO2), Co-based (e.g., Co3O4), and their composite oxides. Cobalt-manganese composite oxides, with their synergistic effect between metals, exhibit excellent catalytic activity and higher stability, making them a research hotspot. Cobalt-manganese spinel oxides are a class of transition metal oxides with the general AB2O4 structure, possessing high crystallinity, large specific surface area, multiple variable valence states, and good charge conductivity. In their structure, Co and Mn elements can be flexibly distributed between octahedral and tetrahedral sites. By adjusting the Co / Mn ratio, the valence state distribution and oxygen vacancy concentration of the catalytic center can be effectively controlled, thereby improving the activation efficiency for PMS. This type of material also has broad application prospects in electrocatalysis, water splitting, and other fields.

[0004] However, although existing studies have confirmed that cobalt-manganese spinel catalysts possess excellent PMS activation capabilities, current synthesis methods generally suffer from complex processes, high precursor costs, and harsh reaction conditions, limiting their large-scale application. Furthermore, some materials exhibit activity decay during repeated cycles, affecting their practical application in water treatment. Therefore, developing a structurally stable, high-performance, and easily scalable cobalt-manganese spinel PMS activator has significant theoretical and engineering application value.

[0005] Patent CN108339550A discloses a method for preparing porous cobalt-manganese spinel microspheres, employing a soft template-hydrothermal method combined with a high-temperature calcination process. By controlling the amount of polyethylene glycol 400, a hollow porous cobalt-manganese spinel structure was successfully constructed. This application uses simple raw materials, and the product exhibits catalytic degradation ability for methylene blue; however, its high energy consumption is a significant issue: the hydrothermal reaction needs to be carried out at 160-240℃, and the subsequent calcination temperature is even higher at 750-900℃, resulting in high overall process costs and hindering large-scale applications. Patent CN104810518A discloses a cobalt-manganese spinel nanomaterial, prepared under normal pressure air atmosphere through a two-step method of oxidation precipitation and intercalation crystallization. The product obtained by this application possesses an ultrafine nanocrystalline structure, high specific surface area, and abundant active sites, significantly improving electrocatalytic performance. However, this application still relies on a hydrothermal reaction at 180-200℃, resulting in high energy consumption, which also limits its practical application potential. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a cobalt-manganese spinel compound PMS activator, its preparation method, and its application.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for preparing a cobalt-manganese spinel compound PMS activator includes the following steps: S1. Preparation of precursor solution: Cobalt source and manganese source are added to deionized water in the reaction vessel and stirred thoroughly to dissolve them and form a homogeneous precursor solution. S2. Precipitation reaction: While keeping the precursor solution under continuous stirring, slowly add alkaline precipitant dropwise to the reaction vessel, adjust the pH of the system to 9-12, and continue stirring for 10-15 minutes after the addition is complete to ensure the formation of a uniform precipitate. S3. Hydrothermal reaction: Continue heating the reactor to 50-80℃ and maintain constant temperature while stirring for 2-6 hours to promote the formation and crystallization of precursor precipitate. S4. Solid-liquid separation and washing: After the reaction is completed, the precipitate is collected by centrifugation and washed alternately with deionized water and anhydrous ethanol until the washing solution is neutral, and the washed precipitate is obtained. S5. Drying and calcination: The washed precipitate is dried at low temperature and then calcined to obtain the cobalt-manganese spinel compound PMS activator.

[0008] Preferably, the cobalt source is cobalt nitrate hexahydrate.

[0009] Preferably, the manganese source is one of manganese sulfate monohydrate and manganese chloride dihydrate.

[0010] Preferably, the alkaline precipitant is any one or more of sodium hydroxide solution, potassium hydroxide solution, or ammonia water.

[0011] Preferably, the stirring speed is 300-600 rpm.

[0012] Preferably, the low-temperature drying process is performed by drying the washed precipitate in an oven at 60-80°C for 12-24 hours.

[0013] Preferably, the calcination temperature is 300-500℃ and the time is 2-4 hours.

[0014] This invention involves the reaction of cobalt and manganese ions with hydroxide ions under alkaline conditions to generate a cobalt-manganese hydroxide coprecipitate. After low-temperature crystallization of the precipitate, calcination is performed to finally obtain a cobalt-manganese spinel compound PMS activator with the chemical formula (Co,Mn). x (Co,Mn) 2-x O4 (1≤x≤2) or Mn x Co 3-x O4 (1≤x≤2) has a stable spinel structure, a large specific surface area, excellent electron transport performance, and multiple redox active sites, which can significantly improve the activation efficiency of PMS.

[0015] The beneficial effects of this invention are: 1. This invention employs a low-temperature solution method with a calcination step, which not only significantly reduces energy consumption and production costs, but also ensures that the product has a high specific surface area and abundant oxygen vacancies. Compared with traditional processes, the method is simple, the process conditions are mild, the energy consumption is low, and it is easy to scale up. 2. The activator obtained by this invention can efficiently activate PMS under neutral pH conditions, and its degradation efficiency for organic pollutants is better than that of traditional high-temperature synthesized materials. In addition, it has a stable structure and can be recycled multiple times. 3. This invention reduces the use of organic solvents, and the reaction byproducts can be recycled and treated, which is in line with the principles of green chemistry and provides a low-cost and sustainable preparation scheme for the industrial application of cobalt manganese spinel compounds. In summary, the preparation method of the present invention is simple, the process conditions are mild, the energy consumption is low, it is easy to scale up, and the use of organic solvents is minimal, which conforms to the principles of green chemistry. The prepared activator has strong activation ability for PMS, stable structure, and can be recycled multiple times. Therefore, the present invention has important application value in the field of wastewater treatment. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 The image shows the SEM image (scale bar 500 nm) of the activator prepared in Example 1 of this invention.

[0018] Figure 2 The image shows a SEM image (scale bar 3 μm) of the activator prepared in Example 1 of this invention.

[0019] Figure 3 The XRD pattern of the activator prepared in Example 1 of this invention is shown.

[0020] Figure 4 The image shows the SEM image (scale bar 500 nm) of the activator prepared in Example 2 of this invention.

[0021] Figure 5 This is a SEM image (scale bar 3 μm) of the activator prepared in Example 2 of the present invention.

[0022] Figure 6 The XRD pattern of the activator prepared in Example 2 of this invention is shown.

[0023] Figure 7 The image shows the SEM image (scale bar 500 nm) of the activator prepared in Example 3 of this invention.

[0024] Figure 8 This is a SEM image (scale bar 3 μm) of the activator prepared in Example 3 of the present invention.

[0025] Figure 9 The XRD pattern of the activator prepared in Example 3 of this invention is shown.

[0026] Figure 10 The EDS spectrum of the activator prepared in Example 3 of this invention is shown.

[0027] Figure 11 The degradation curve of the activator prepared in Example 3 of the present invention after cyclic use test is shown.

[0028] Figure 12 The image shows the SEM image (scale bar 500 nm) of the activator prepared in Example 4 of this invention.

[0029] Figure 13 This is a SEM image (scale bar 3 μm) of the activator prepared in Example 4 of the present invention.

[0030] Figure 14 The XRD pattern of the activator prepared in Example 4 of this invention is shown.

[0031] Figure 15 The image shows the SEM image (scale bar 500 nm) of the activator prepared in Example 5 of this invention.

[0032] Figure 16 This is a SEM image (scale bar 3 μm) of the activator prepared in Example 5 of the present invention.

[0033] Figure 17The XRD pattern of the activator prepared in Example 5 of this invention is shown.

[0034] Figure 18 The image shows the SEM image (scale bar 500 nm) of the activator prepared in Example 6 of this invention.

[0035] Figure 19 This is a SEM image (scale bar 3 μm) of the activator prepared in Example 6 of the present invention.

[0036] Figure 20 The XRD pattern of the activator prepared in Example 6 of this invention is shown.

[0037] Figure 21 The image shows the SEM image (scale bar 500 nm) of the activator prepared in Example 7 of this invention.

[0038] Figure 22 The image shows a SEM image (scale bar 3 μm) of the activator prepared in Example 7 of this invention.

[0039] Figure 23 The XRD pattern of the activator prepared in Example 7 of this invention.

[0040] Figure 24 The degradation curves of RhB by the activators prepared in Examples 1-7 of this invention are shown. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1 A method for preparing a cobalt-manganese spinel compound PMS activator includes the following steps: S1. In a reaction vessel, add 0.01 mol cobalt nitrate hexahydrate and 0.01 mol manganese sulfate monohydrate to 100 mL of deionized water and stir thoroughly to dissolve them (stirring speed is 300 rpm) to form a homogeneous precursor solution. S2. While keeping the precursor solution under continuous stirring (stirring speed of 300 rpm), slowly add 1 mol / L sodium hydroxide solution dropwise to the reactor to adjust the pH of the system to 12. After the addition is completed, continue stirring for 10 min to ensure the formation of a uniform precipitate. S3. Continue heating the reactor to 60°C and maintain the constant temperature while stirring for 2 hours (stirring speed 300 rpm) to promote the formation and crystallization of the precursor precipitate. S4. After the reaction is complete, the precipitate is collected by centrifugation and washed alternately with deionized water and anhydrous ethanol until the washing solution is neutral, thus obtaining the washed precipitate. S5. The washed precipitate was dried in an oven at 60°C for 12 hours, and then calcined in a muffle furnace at 400°C for 2 hours to obtain the cobalt manganese spinel compound PMS activator. SEM images of the activator at different magnifications were obtained using scanning electron microscopy, as shown below. Figure 1 and Figure 2 As shown, the activator is observed to be granular with a particle size of approximately 100-200 nm, uniformly distributed, and exhibiting good dispersibility. The XRD pattern obtained using an X-ray diffractometer is shown below. Figure 3 As shown, the characteristic diffraction peaks of the obtained sample are highly matched with the (Co,Mn)(Co,Mn)2O4 spinel structure corresponding to the standard card (PDF# 18-0408), indicating that the sample successfully formed the target crystal structure.

[0043] Example 2 This embodiment is operated in the same way as in Example 1, except that the following conditions are changed: the 1 mol / L sodium hydroxide solution is replaced with 25% ammonia water; the calcination temperature is adjusted from 400℃ to 450℃ and the calcination time is adjusted from 2h to 2.5h to obtain the cobalt manganese spinel compound PMS activator. SEM images of the activator at different magnifications were obtained using scanning electron microscopy, as shown below. Figure 4 and Figure 5 As shown, the sample still exhibits a granular structure, similar in morphology to the sample in Example 1, with a particle size of approximately 100-200 nm and a uniform distribution, indicating that the ammonia precipitation method is also beneficial for forming a good microstructure. The XRD pattern obtained using an X-ray diffractometer is shown below. Figure 6 As shown, the characteristic diffraction peaks of the obtained sample are highly matched with the (Co,Mn)(Co,Mn)2O4 spinel structure corresponding to the standard card (PDF# 18-0408), and the crystallinity is similar to that of Example 1, indicating that the product also has ideal crystallinity.

[0044] Example 3 A method for preparing a cobalt-manganese spinel compound PMS activator includes the following steps: S1. In a reaction vessel, add 0.01 mol cobalt nitrate hexahydrate and 0.02 mol manganese sulfate monohydrate to 100 mL of deionized water and stir thoroughly to dissolve them (stirring speed is 600 rpm) to form a homogeneous precursor solution. S2. While keeping the precursor solution under continuous stirring (stirring speed of 600 rpm), slowly add 1 mol / L sodium hydroxide solution dropwise to the reactor to adjust the pH of the system to 12. After the addition is complete, continue stirring for 10 min to ensure the formation of a uniform precipitate. S3. Continue heating the reactor to 60°C and maintain the constant temperature while stirring for 2 hours (stirring speed 600 rpm) to promote the formation and crystallization of the precursor precipitate. S4. After the reaction is complete, the precipitate is collected by centrifugation and washed alternately with deionized water and anhydrous ethanol until the washing solution is neutral, thus obtaining the washed precipitate. S5. The washed precipitate was dried in an oven at 60°C for 12 hours, and then calcined in a muffle furnace at 400°C for 2 hours to obtain the cobalt manganese spinel compound PMS activator. SEM images of the activator at different magnifications were obtained using scanning electron microscopy, as shown below. Figure 7 and Figure 8 As shown, the activator is observed to be granular with a particle size of approximately 100-200 nm, uniformly distributed, and exhibiting good dispersibility. The XRD pattern obtained using an X-ray diffractometer is shown below. Figure 9 As shown, the characteristic diffraction peaks of the obtained sample highly match the (Co,Mn)(Co,Mn)₂O₄ spinel structure corresponding to the standard card (PDF# 18-0408), and the crystallinity is high, indicating that the product has good crystallinity; in addition, the EDS spectrum obtained is as follows. Figure 10 As shown in the figure, the product is mainly composed of three elements: Co, Mn, and O. The detected Si element originated from the silicon wafer substrate used in the analysis, further confirming the successful construction of the cobalt-manganese spinel structure.

[0045] Example 4 This embodiment is operated in the same way as in Example 3, except that the following conditions are changed: manganese sulfate monohydrate is replaced with manganese chloride dihydrate to obtain cobalt manganese spinel compound PMS activator; SEM images of the activator at different magnifications were obtained using scanning electron microscopy, as shown below. Figure 12 and Figure 13 As shown, the activator is observed to be granular, similar to that in Example 3, with a particle size of approximately 100-200 nm, uniformly distributed, and exhibiting good dispersibility. The XRD pattern obtained using an X-ray diffractometer is shown below. Figure 14 As shown, the characteristic diffraction peaks of the obtained sample are highly matched with the (Co,Mn)(Co,Mn)2O4 spinel structure corresponding to the standard card (PDF# 18-0408), and the crystallinity is high, indicating that the product has good crystallinity.

[0046] Example 5 This embodiment is operated in the same way as in Example 3, except that the following conditions are changed: the 1 mol / L sodium hydroxide solution is replaced with 1 mol / L potassium hydroxide to obtain the cobalt manganese spinel compound PMS activator. SEM images of the activator at different magnifications were obtained using scanning electron microscopy, as shown below. Figure 15 and Figure 16 As shown, the activator is observed to be granular, similar to that in Example 3, with a particle size of approximately 100-200 nm, uniformly distributed, and exhibiting good dispersibility. The XRD pattern obtained using an X-ray diffractometer is shown below. Figure 17 As shown, the characteristic diffraction peaks of the obtained sample are highly matched with the (Co,Mn)(Co,Mn)2O4 spinel structure corresponding to the standard card (PDF# 18-0408), and the crystallinity is high, indicating that the product has good crystallinity.

[0047] Example 6 S1. In a reaction vessel, add 0.02 mol cobalt nitrate hexahydrate and 0.01 mol manganese sulfate monohydrate to 100 mL of deionized water and stir thoroughly to dissolve them (stirring speed is 600 rpm) to form a homogeneous precursor solution. S2. While keeping the precursor solution under continuous stirring (stirring speed of 600 rpm), slowly add 1 mol / L sodium hydroxide solution dropwise to the reactor to adjust the pH of the system to 12. After the addition is complete, continue stirring for 10 min to ensure the formation of a uniform precipitate. S3. Continue heating the reactor to 60°C and maintain the constant temperature while stirring for 2 hours (stirring speed 600 rpm) to promote the formation and crystallization of the precursor precipitate. S4. After the reaction is complete, the precipitate is collected by centrifugation and washed alternately with deionized water and anhydrous ethanol until the washing solution is neutral, thus obtaining the washed precipitate. S5. The washed precipitate was dried in an oven at 60°C for 12 hours, and then calcined in a muffle furnace at 400°C for 2 hours to obtain the cobalt manganese spinel compound PMS activator. SEM images of the activator at different magnifications were obtained using scanning electron microscopy, as shown below. Figure 18 and Figure 19 As shown, the activator is observed to be granular, similar to that in Example 3, with a particle size of approximately 100-200 nm, uniformly distributed, and exhibiting good dispersibility. The XRD pattern obtained using an X-ray diffractometer is shown below. Figure 20As shown, the sample exhibits clear spinel structure diffraction characteristic peaks. The characteristic diffraction peaks of the obtained sample are highly matched with the spinel structure of the standard card (PDF# 23-1237) MnCo2O4, and the crystallinity is high, indicating that the product has good crystallinity.

[0048] Example 7 S1. In a reaction vessel, add 0.02 mol cobalt nitrate hexahydrate and 0.01 mol manganese sulfate monohydrate to 100 mL of deionized water and stir thoroughly to dissolve them (stirring speed is 600 rpm) to form a homogeneous precursor solution. S2. While keeping the precursor solution under continuous stirring (stirring speed of 600 rpm), slowly add 1 mol / L sodium hydroxide solution dropwise to the reactor to adjust the pH of the system to 12. After the addition is complete, continue stirring for 10 min to ensure the formation of a uniform precipitate. S3. Continue heating the reactor to 80°C and maintain the constant temperature while stirring for 2 hours (stirring speed is 600 rpm) to promote the formation and crystallization of the precursor precipitate. S4. After the reaction is complete, the precipitate is collected by centrifugation and washed alternately with deionized water and anhydrous ethanol until the washing solution is neutral, thus obtaining the washed precipitate. S5. The washed precipitate was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 500°C for 2 hours to obtain the cobalt manganese spinel compound PMS activator. SEM images of the activator at different magnifications were obtained using scanning electron microscopy, as shown below. Figure 21 and Figure 22 As shown, the activator is observed to be granular, similar to that in Example 3, with a particle size of approximately 100-200 nm, uniformly distributed, and exhibiting good dispersibility. The XRD pattern obtained using an X-ray diffractometer is shown below. Figure 23 As shown, the sample exhibits clear spinel structure diffraction characteristic peaks. The characteristic diffraction peaks of the obtained sample are highly matched with the corresponding MnCo2O4 spinel structure of the standard card (PDF# 23-1237), and the crystallinity is high, indicating that the product has good crystallinity.

[0049] The catalytic performance of the samples obtained in Examples 1-7 was tested using the following methods: 1 mM persulfate was added to 50 mL of Rhodamine B (RhB) solution with an initial concentration of 50 mg / L. After stirring thoroughly, 10 mg of sample was added to the solution, and the mixture was stirred to carry out the degradation experiment. 2 mL samples were taken at regular intervals, and 20 μL of 1 M sodium sulfate solution was added to the samples to terminate the degradation reaction. The RhB concentration in the samples was then measured using a UV spectrophotometer, and the degradation rate (%) was calculated. Degradation rate (%) = (initial RhB concentration - RhB concentration after degradation) / initial RhB concentration × 100%. The results are shown in Table 1. Table 1 The test results from various embodiments show that when the molar ratio of Co / Mn is 1:1-2, the product obtained is (Co,Mn)(Co,Mn)₂O₄, and when the molar ratio of Co / Mn is 2:1, the product obtained is MnCo₂O₄. Furthermore, the catalytic activity of (Co,Mn)(Co,Mn)₂O₄ is higher than that of MnCo₂O₄. This indicates that a higher cobalt content alters the crystal structure, facilitating the formation of MnCo₂O₄ with a higher cobalt content. Although the catalytic effect of MnCo₂O₄ is somewhat lower than that of (Co,Mn)(Co,Mn)₂O₄, it still exhibits excellent oxidation activity.

[0050] Using the above method, the sample prepared in Example 3 was subjected to a cyclic use test, and the results are as follows. Figure 11 As shown in the figure, after five repeated uses, the activator still achieved a degradation efficiency of 88.4% for RhB within 30 minutes, indicating that the activator has good catalytic stability and reusability.

[0051] The degradation curve was plotted as a line graph with the ratio of post-degradation RhB concentration to initial RhB concentration multiplied by 100% on the ordinate and time (0-30 min) on the abscissa. Figure 24 As shown.

[0052] In summary, the activator prepared by this invention has high efficiency, good stability, and can be recycled and reused, which is conducive to large-scale use and has important application value in the field of wastewater treatment.

[0053] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a cobalt-manganese spinel compound PMS activator, characterized in that, Includes the following steps: S1. Add the cobalt source and manganese source to deionized water and stir to dissolve them to form a precursor solution; S2. While stirring continuously, slowly add an alkaline precipitant to the precursor solution to adjust the pH of the system to 9-12. After the addition is complete, continue stirring for 10-15 minutes to generate a precipitate. S3. Heat to 50-80℃ and maintain constant temperature, then stir continuously for 2-6 hours. S4. After the reaction is complete, the precipitate is collected by centrifugation and washed alternately with deionized water and anhydrous ethanol until the washing solution is neutral, thus obtaining the washed precipitate. S5. The washed precipitate is dried at low temperature and then calcined to obtain the cobalt-manganese spinel compound PMS activator.

2. The method for preparing a cobalt-manganese spinel compound PMS activator according to claim 1, characterized in that, The cobalt source is cobalt nitrate hexahydrate.

3. The method for preparing a cobalt-manganese spinel compound PMS activator according to claim 1, characterized in that, The manganese source is either manganese sulfate monohydrate or manganese chloride dihydrate.

4. The method for preparing a cobalt-manganese spinel compound PMS activator according to claim 1, characterized in that, The alkaline precipitant is any one or more of sodium hydroxide solution, potassium hydroxide solution, or ammonia water.

5. The method for preparing a cobalt-manganese spinel compound PMS activator according to claim 1, characterized in that, The stirring speed is 300-600 rpm.

6. The method for preparing a cobalt-manganese spinel compound PMS activator according to claim 1, characterized in that, The low-temperature drying process involves drying the washed precipitate in an oven at 60-80℃ for 12-24 hours.

7. The method for preparing a cobalt-manganese spinel compound PMS activator according to claim 1, characterized in that, The calcination temperature is 300-500℃, and the time is 2-4 hours.

8. A cobalt-manganese spinel compound PMS activator, characterized in that, Prepared according to the method according to any one of claims 1-7.

9. The application of the cobalt-manganese spinel compound PMS activator according to claim 8 in the field of wastewater treatment.

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