Method for treating organic pollutant wastewater by using manganese monoxide-graphite diacetylene nano-confined catalytic material to activate persulfate

Abstract

The application discloses a method for treating organic pollutant wastewater by using manganese monoxide-graphite diacetylene nano-confined catalytic material to activate persulfate, the method is to degrade and treat organic pollutant wastewater by using manganese monoxide-graphite diacetylene nano-confined catalytic material as a catalyst for activating persulfate, and the nano-confined catalytic material comprises graphite diacetylene nanosheets, and manganese monoxide nanoparticles are confined between the layered structures of the graphite diacetylene nanosheets.The method has the advantages of rich active sites, fast electron transfer and stable structure, so that the catalytic degradation system is not only high in efficiency, but also strong in adaptability, and shows good degradation effect on various organic pollutants, and has the advantages of simple process, convenient operation, high treatment efficiency, good removal effect, strong adaptability, green environmental protection and the like, and has important promoting significance for deep purification of organic pollutant wastewater.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional nanomaterial preparation technology, and relates to a method for activating persulfate to treat organic pollutant wastewater using manganese monoxide@graphidiyne nanoconfined catalytic material. Background Technology

[0002] Advanced persulfate oxidation technology is one of the important methods for removing organic pollutants from water bodies. The key to the efficient activation of persulfate in this technology lies in developing a highly efficient, stable, and environmentally friendly heterogeneous catalyst. Among numerous candidate materials, manganese monoxide is considered a highly promising catalytic material due to its low cost, good environmental compatibility, rich redox properties, and low biotoxicity. Furthermore, studies have shown that manganese monoxide can effectively catalyze the decomposition of persulfate, generating reactive species such as sulfate radicals, exhibiting considerable degradation activity against various organic compounds, and demonstrating promising application prospects.

[0003] However, manganese monoxide, when used as a heterogeneous catalyst for activating persulfate, suffers from two significant technical drawbacks that severely restrict its performance and sustainability. First, manganese monoxide is prone to manganese ion leaching under acidic or prolonged reaction conditions. This loss of active components not only leads to rapid catalyst deactivation and shortens its lifespan but may also cause secondary metal pollution of water bodies, contradicting the original intent of green water treatment technology. Second, manganese monoxide nanoparticles possess high surface energy, making them highly susceptible to uncontrolled aggregation during preparation and catalysis. This aggregation significantly reduces the effective specific surface area of ​​the catalyst, masks active sites, and hinders contact between reactants and active centers, thereby significantly weakening its intrinsic catalytic activity.

[0004] Currently, anchoring manganese monoxide nanoparticles onto suitable supports is a common approach to improve their dispersibility and stability. However, traditional physical mixing or simple impregnation loading methods often fail to form strong chemical interactions between manganese monoxide and the support (such as activated carbon, conventional graphene, etc.), resulting in uneven size and uncontrollable distribution of the loaded manganese monoxide particles, as well as weak binding force with the support. Consequently, during vigorous catalytic reactions, the loaded manganese monoxide particles may still migrate, aggregate, or even detach from the support, failing to fundamentally solve the problems of ion leaching and poor stability.

[0005] The aforementioned problems make it difficult for existing manganese monoxide catalysts to be widely used for removing organic pollutants from water bodies.

[0006] To address the above problems, this invention is proposed. 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 treating organic pollutant wastewater by activating persulfate using manganese monoxide@graphitediyne nano-confined catalytic material, which is simple in process, convenient in operation, high in treatment 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: A method for treating organic pollutant wastewater by activating persulfate using manganese monoxide@graphidyne nanoconfined catalytic material, wherein the manganese monoxide@graphidyne nanoconfined catalytic material is used as a catalyst to activate persulfate and degrade organic pollutant wastewater; the manganese monoxide@graphidyne nanoconfined catalytic material comprises graphidyne nanosheets, and manganese monoxide nanoparticles are confined between the layered structures of the graphidyne nanosheets.

[0009] In a further improvement to the above method, the manganese monoxide nanoparticles in the manganese monoxide@graphidiyne nanoconfined catalytic material have a particle size of 5 nm to 10 nm.

[0010] A further improvement to the above method, the preparation method of the manganese monoxide@graphidyne nanoconfined catalytic material includes the following steps: S1. Mix graphdiyne, manganese salt, N,N-dimethylformamide and anhydrous ethanol, and disperse by ultrasonication to obtain a mixture; S2. The mixture obtained in step S1 is subjected to a solvothermal reaction to obtain the precursor material; S3. The precursor material obtained in step S2 is calcined under an inert atmosphere or a nitrogen atmosphere to obtain manganese monoxide@graphidiyne nanoconfined catalytic material.

[0011] In a further improvement to the above method, in step S1, the mass ratio of graphdiyne to manganese salt is 1:8 to 32.

[0012] In a further improvement to the above method, in step S1, the mass ratio of graphdiyne to manganese salt is 1:10 to 20.

[0013] In a further improvement to the above method, in step S1, the manganese salt is manganese chloride; the mass-to-volume ratio of the manganese salt to anhydrous ethanol is 0.4 g:30 mL; the volume ratio of N,N-dimethylformamide to anhydrous ethanol is 1:1; and the ultrasonic dispersion time is 30 min to 60 min.

[0014] In a further improvement to the above method, in step S2, the temperature of the solvothermal reaction is 120℃~180℃; the time of the solvothermal reaction is 12 h~48 h; after the solvothermal reaction is completed, the following treatment is also included: the product is vacuum filtered, washed with ethanol, and vacuum dried at 60℃ for 12 h~48 h to obtain the precursor material.

[0015] In a further improvement to the above method, in step S3, the calcination is performed by first heating the temperature to 450°C at a heating rate of 5°C / min and holding it at that temperature for 2 hours, and then heating it to 700°C at the same rate and holding it at that temperature for 1 hour to obtain manganese monoxide@graphidiyne nanoconfined catalytic material.

[0016] A further improvement to the above method, using manganese monoxide@graphidiyne nano-confined catalytic material as a catalyst to activate persulfate for the degradation of organic pollutant wastewater, includes the following steps: Manganese monoxide@graphitediyne nanoconfined catalytic material is mixed with organic pollutant wastewater, and persulfate is added to carry out a Fenton-like catalytic reaction to complete the degradation treatment of organic pollutant wastewater.

[0017] In a further improvement to the above method, the amount of manganese monoxide@graphidyne nano-confined catalytic material added is 0.05 g to 0.2 g per liter of the organic pollutant wastewater; and the amount of persulfate added is 0.1 g to 0.5 g per liter of the organic pollutant wastewater.

[0018] In a further improvement to the above method, the persulfate is permonosulfate; the organic pollutant includes antibiotics; the initial concentration of antibiotics in the wastewater is ≤10 mg / L; and the antibiotic is tetracycline.

[0019] The above method is further improved in that the time for the Fenton-like catalytic reaction is 6 min to 18 min. Compared with the prior art, the advantages of the present invention are as follows: (1) In view of the shortcomings of existing manganese monoxide catalytic materials, such as small specific surface area, few active sites, poor dispersibility, low catalytic activity, and easy leaching, and the resulting defects such as difficulty in efficiently activating persulfate, difficulty in efficiently degrading organic pollutants and poor reuse effect, this invention creatively proposes a method for treating organic pollutant wastewater by activating persulfate using manganese monoxide@graphidyne nanoconfined catalytic material. The manganese monoxide@graphidyne nanoconfined catalytic material is used as a catalyst to activate persulfate and degrade organic pollutant wastewater. The manganese monoxide@graphidyne nanoconfined catalytic material includes graphidyne nanosheets, and manganese monoxide nanoparticles are confined between the layered structure of the graphidyne nanosheets. In this invention, graphdiyne nanosheets are used as a carrier. Their unique two-dimensional planar structure, large specific surface area, and uniformly distributed alkyne bonds provide an ideal template for the uniform adsorption and confined growth of manganese ions. On one hand, the huge specific surface area greatly increases the loading capacity of the active component; on the other hand, the unique strong interaction between the alkyne bonds and manganese ions is the microscopic basis for achieving the "in-situ growth, uniform dispersion, and strong bonding" of manganese monoxide nanoparticles, which is not present in traditional carbon materials (such as activated carbon and graphene). Based on this, manganese monoxide nanoparticles are confined within the layered structure of graphdiyne nanosheets. On the one hand, the strong interaction between the π electrons of the alkyne bonds in graphdiyne and manganese monoxide allows for the adsorption of more manganese monoxide. The nanoparticles are firmly fixed within the layered structure of graphdiyne nanosheets. In particular, through confinement, manganese monoxide nanoparticles can be "locked" within the graphdiyne layers, and the leaching of manganese ions is effectively prevented under the protection of graphdiyne. This not only improves the catalytic activity of the catalytic material but also enhances its structural stability, exhibiting excellent reusability and being more environmentally friendly. On the other hand, the uneven electron distribution on the surface of graphdiyne also increases the migration resistance of manganese monoxide nanoparticles, thereby effectively preventing their aggregation and improving the dispersion uniformity of manganese monoxide nanoparticles within the layered structure of graphdiyne nanosheets. In particular, the particle size of manganese monoxide nanoparticles can be controlled to be 5 nm to 10 nm, which can increase the specific surface area and the number of active sites of the catalytic material, enabling it to exhibit excellent catalytic performance. Compared with conventional manganese monoxide catalytic materials, the manganese monoxide@graphitediyne nanoconfined catalytic material used in this invention has advantages such as large specific surface area, numerous active sites, high loading, good dispersibility, high catalytic activity, and good stability. It is a novel manganese-based catalyst with excellent catalytic performance and stable structure. As a catalyst for activating persulfate, it can rapidly form a degradation system containing a large number of strongly oxidizing free radicals and non-free radicals, thereby achieving efficient degradation of different types of organic pollutants in wastewater. Taking tetracycline as an example, it can achieve efficient removal of tetracycline in a very short time (6-15 minutes).Furthermore, because the manganese monoxide nanoparticles are confined within graphdiyne, the catalytic material of this invention exhibits minimal loss of active components during repeated use and slow catalytic performance degradation. Simultaneously, its excellent physicochemical stability ensures its ability to be used multiple times to treat organic pollutant wastewater, significantly reducing the unit water treatment cost. This overcomes the economic and technical bottlenecks of homogeneous manganese catalysts and traditional supported manganese catalysts, which are either single-use or have short lifespans, thus facilitating practical engineering applications. In addition, because the manganese monoxide nanoparticles are confined within graphdiyne, the catalytic active components are less affected by pH, allowing the manganese monoxide@graphdiyne catalyst to maintain excellent degradation performance on pollutants even at pH values ​​of 3-11, greatly enhancing the practical applicability of this catalytic material. More importantly, in the manganese monoxide@graphidyne nanoconfined catalytic material of this invention, the graphdiyne and manganese monoxide nanoparticles are not simply physically mixed, but form a strongly coupled interface. The highly conductive network of graphdiyne greatly promotes the efficiency of electron transfer from manganese monoxide to persulfate at the interface and accelerates the generation of active species. Simultaneously, the electronic structure modulation that may occur at the interface (such as changes in electron cloud density at active sites induced by electron transfer) further enhances the catalytic material's activation ability for persulfate and its oxidative degradation efficiency for organic matter, exhibiting a synergistic catalytic effect of "1+1≥2". This invention's method for activating persulfate to treat organic pollutant wastewater using manganese monoxide@graphidyne nanoconfined catalytic material benefits from the material's abundant active sites, rapid electron transfer, and stable structure. This results in a catalytic degradation system that is not only highly efficient but also highly adaptable, showing good degradation effects on various organic pollutants. It possesses advantages such as simple process, convenient operation, high treatment efficiency, good removal effect, strong adaptability, and environmental friendliness, and has significant implications for the deep purification of organic pollutant wastewater.

[0020] (2) In the preparation method of the manganese monoxide@graphidyne nanoconfined catalytic material used in this invention, manganese salt and graphidyne are first mixed in N,N-dimethylformamide and anhydrous ethanol. During ultrasonic dispersion, the abundant alkyne bonds on the surface of graphidyne are used to strongly chemically anchor manganese ions, so that more manganese ions can be uniformly adsorbed between the layered structures of graphidyne nanosheets. This is the basis for achieving high dispersion loading of manganese species and inhibiting their aggregation. Furthermore, the mixture is subjected to a solvothermal reaction. During the solvothermal reaction, the anchored manganese ions grow in situ as manganese precursors and are uniformly confined into the graphidyne interlayer. This process is the key to controlling the size and dispersibility of manganese monoxide nanoparticles. Subsequently, by calcining the precursor, the high-manganese-content precursor can be transformed in situ into manganese monoxide nanoparticles with good crystallinity, uniform and fine particle size, and good dispersion uniformity under relatively mild conditions. Specifically, calcination is first carried out at a temperature of 450℃, which can gently transform the manganese species in the precursor into manganese monoxide crystal nuclei and strengthen the interfacial bonding with graphdiyne, avoiding structural damage caused by violent reactions. Then, calcination is carried out at a temperature of 700℃, which further allows the manganese monoxide grains to grow and crystallize appropriately. Under the premise of not excessive agglomeration, its crystal phase and electronic structure are optimized, thereby achieving the best balance between "high dispersion" and "high crystallinity", and finally obtaining a composite structure with the highest catalytic activity. Of particular importance is that during this calcination process, a strong interaction is formed between the π electrons of the pyridyl bonds in graphdiyne and the manganese species, ultimately establishing a stable, strongly interacting interface after calcination. This strong interfacial force not only firmly "locks" the manganese monoxide nanoparticles within the graphdiyne interlayer, but also increases the migration resistance of the manganese monoxide nanoparticles due to the uneven electron distribution on the graphdiyne surface, effectively preventing agglomeration and sintering during use. Furthermore, the confinement of the graphdiyne within the interlayer also helps prevent the leaching of its metal ions. Ultimately, a manganese monoxide@graphdiyne nano-confined catalytic material with a large specific surface area, high manganese oxide loading, abundant active sites, good dispersibility, strong interfacial bonding, and good stability was successfully prepared. In addition, the raw materials required for the entire preparation process are readily available, the reaction conditions are mild and controllable, and there is no need to use expensive or highly toxic reagents. It also has the advantages of simple process, mild conditions, and strong controllability, making it easy to prepare on a large scale and suitable for industrial production. Furthermore, the preparation method of this invention combines structural design with controllable preparation, providing a practical new path for the large-scale preparation of high-performance, long-life manganese-based water treatment catalysts.

[0021] (3) In this invention, by optimizing the mass ratio of graphdiyne to manganese salt to 1:8 to 32, the manganese monoxide nanoparticles in the prepared manganese monoxide@graphdiyne nanoconfined catalytic material have a moderate loading and better dispersion, and have better catalytic performance and more stable structure, which can meet different application requirements. Attached Figure Description

[0022] 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.

[0023] Figure 1 The image shows the X-ray diffraction pattern of the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 of this invention.

[0024] Figure 2 The elemental distribution diagram is shown for the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 of this invention.

[0025] Figure 3 The images show transmission electron microscopy (TEM) images and high-resolution TEM images of the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 of this invention.

[0026] Figure 4 The image shows the X-ray photoelectron spectrum of the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 of this invention.

[0027] Figure 5 This is a comparison diagram of the degradation effects of manganese monoxide@graphidyne nanoconfined catalytic materials (A1, A2, A3) and graphidyne on tetracycline in Example 1 of the present invention.

[0028] Figure 6 This is a comparison of the degradation effects of manganese monoxide@graphidiyne nanoconfined catalytic material (A2) on tetracycline under different pH conditions in Example 2 of the present invention.

[0029] Figure 7 This is a comparison of the degradation effects of manganese monoxide@graphidiyne nanoconfined catalytic material (A2) on tetracycline under different coexisting ion conditions in Example 3 of the present invention.

[0030] Figure 8 This is a comparison chart showing the degradation effect of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) on tetracycline in different actual water bodies in Example 4 of the present invention.

[0031] Figure 9 This is a comparison chart showing the repeated degradation effect of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) on tetracycline in wastewater in Example 4 of the present invention. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] Example 1 A method for treating organic pollutant wastewater using manganese monoxide@graphitdiyne nanoconfined catalytic material to activate persulfate (PMS) involves using manganese monoxide@graphitdiyne nanoconfined catalytic material as a catalyst to degrade tetracycline wastewater, including the following steps: Accurately weigh 5 mg of manganese monoxide@graphidiyne nanoconfined catalytic materials (A1, A2, A3) and add them to 50 mL of tetracycline aqueous solution with an initial concentration of 10 mg / L (pH 5). Mechanically stir for 30 min in the dark to allow tetracycline to reach adsorption-desorption equilibrium on the catalyst surface. Then, add 5 mg of permonosulfate (PMS) to each system to initiate a Fenton-like catalytic reaction and degrade the tetracycline wastewater for 12 min, thus completing the removal of tetracycline from the wastewater.

[0035] In this embodiment, the manganese monoxide@graphidyne nanoconfined catalytic material (A1) used includes graphidyne nanosheets and manganese monoxide nanoparticles, with the manganese monoxide nanoparticles confined within the layered structure of the graphidyne nanosheets.

[0036] In this embodiment, the preparation method of the manganese monoxide@graphidyne nanoconfined catalytic material (A1) includes the following steps: S1. Obtain graphdiyne, the preparation method of which is as follows: First, 1.00 g of hexabromobenzene, 1.20 g of calcium carbide, 0.03 g of palladium catalyst (tetraphenylphosphine palladium), and 0.50 g of copper catalyst (CuI) were mixed and an organic solvent was added, comprising 40 mL of pyridine, 40 mL of tetrahydrofuran, 50 mL of toluene, and 40 mL of ethyl acetate. A single-necked flask was used as the reaction vessel, and the mixture was reacted at a constant temperature of 80 °C for 12 h. Subsequently, 10 mL of a 1 mol / L tetrabutylammonium fluoride solution was added to the reaction system, and the reaction was continued at 80 °C for another 1 h. Afterward, 20 mL of deionized water and 10 mL of concentrated hydrochloric acid were added stepwise, the reaction temperature was adjusted to 60 °C, and the reaction was continued for 35 h to obtain a graphdiyne slurry product. The graphdiyne slurry product was rotary evaporated at 85°C to obtain a viscous substance, which was then ultrasonically dispersed in anhydrous ethanol. High-boiling-point organic matter and copper catalyst were removed by repeated centrifugation with anhydrous ethanol and dilute ammonia. The product was then treated with hot concentrated hydrochloric acid, filtered, and dried to obtain graphdiyne.

[0037] S2. Following a mass ratio of manganese salt to graphdiyne of 8:1, the graphdiyne, manganese salt, N,N-dimethylformamide, and anhydrous ethanol obtained in step S1 are mixed and ultrasonically dispersed to obtain a homogeneous mixture, specifically: Add 0.4 g of anhydrous manganese chloride and 0.05 g of graphdiyne prepared in step S1 to a mixed solution of 30 mL of nitrogen, nitrogen-dimethylformamide and 30 mL of anhydrous ethanol, and sonicate for 30 min to mix the components evenly to obtain a mixed solution.

[0038] S3. The mixture obtained in step S2 is subjected to a solvothermal reaction to obtain the precursor material, specifically: The mixture was transferred to a polytetrafluoroethylene-lined autoclave, and the autoclave was placed in an oven for solvothermal reaction at 140 °C for 24 h. The reacted material was washed 3-5 times with anhydrous ethanol and dried in a vacuum drying oven at 60 °C for 12 h to obtain the precursor material.

[0039] S4. The precursor material obtained in step S3 is calcined to obtain manganese monoxide@graphidiyne nano-confined catalytic material, specifically: The precursor material was placed in a tube furnace and heated to 450°C at a heating rate of 5°C / min, and calcined at 450°C for 2 hours; then heated to 700°C at a heating rate of 5°C / min, and calcined at 700°C for 1 hour to obtain manganese monoxide@graphidiyne nanoconfined catalytic material, denoted as A1.

[0040] In this embodiment, the manganese monoxide@graphidyne nanoconfined catalytic material (A2) used includes graphidyne nanosheets and manganese monoxide nanoparticles, with the manganese monoxide nanoparticles confined within the layered structure of the graphidyne nanosheets.

[0041] In this embodiment, the particle size of manganese monoxide nanoparticles in the manganese monoxide@graphidyne nanoconfined catalytic material (A2) is 7 nm.

[0042] In this embodiment, the preparation method of manganese monoxide@graphidyne nanoconfined catalytic material (A2) is basically the same as that of manganese monoxide@graphidyne nanoconfined catalytic material (A1), except that in the preparation method of manganese monoxide@graphidyne nanoconfined catalytic material (A2), the amount of manganese chloride used is 0.8 g, that is, the mass ratio of manganese chloride to graphidyne is 16:1.

[0043] In this embodiment, the preparation method of manganese monoxide@graphidyne nanoconfined catalytic material (A3) is basically the same as that of manganese monoxide@graphidyne nanoconfined catalytic material (A1), except that in the preparation method of manganese monoxide@graphidyne nanoconfined catalytic material (A3), the amount of manganese chloride used is 1.6 g, that is, the mass ratio of manganese chloride to graphidyne is 32:1.

[0044] Figure 1 This is the X-ray diffraction pattern of the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 of this invention. Figure 1 It can be seen that, compared with the diffraction peak of graphdiyne, the new diffraction peak of the manganese monoxide@graphdiyne nanoconfined catalytic material prepared in this invention is completely consistent with the diffraction peak of manganese monoxide nanoparticles, which indicates that manganese monoxide has been successfully confined.

[0045] Figure 2 The elemental distribution diagram is shown for the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 of this invention. Figure 2 In the image, a is the SEM image of A2, b is the carbon element distribution map, c is the oxygen element distribution map, and d is the manganese element distribution map. From Figure 2 It can be seen that the manganese monoxide@graphitediyne nanoconfined catalytic material (A2) of the present invention contains carbon, oxygen and manganese.

[0046] Figure 3 The images show transmission electron microscopy (TEM) images and high-resolution TEM images of the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 of this invention. Figure 3 In the image, a is a transmission electron microscope (TEM) image, and b is a high-resolution TEM image. (From...) Figure 3 It is known that graphdiyne is a nanosheet, and nanoparticles with a diameter of 7 nm are confined within the layered structure of the ultrathin nanosheets. The high-resolution transmission electron microscopy image of these particles shows lattice fringes with a lattice spacing of 0.227 nm, which is in perfect agreement with the (200) lattice of manganese monoxide.

[0047] Figure 4 The image shows the X-ray photoelectron spectrum of the manganese monoxide@graphidiyne nanoconfined catalytic material (A2) prepared in Example 1 of this invention. Figure 4 In the figure, peaks mainly appear at 654.0 eV, 652.8 eV, 644.7 eV and 641.6 eV, which are basically consistent with the binding energy of manganese.

[0048] The above results demonstrate that the manganese monoxide@graphidiyne nanoconfined catalytic material of the present invention has been successfully prepared.

[0049] In the Fenton-like catalytic reaction, 3 mL samples were taken at specified time points (e.g., 0, 2 min, 4 min, 6 min, 8 min, 10 min, and 12 min) and immediately filtered through a 0.22 μm organic phase membrane to separate the catalyst. The concentration of tetracycline in the filtrate was determined using a UV-Vis spectrophotometer, and the degradation efficiency of different catalysts was calculated accordingly. The results are shown below. Figure 5 As shown.

[0050] Figure 5 This is a comparison of the degradation effects of manganese monoxide@graphidiyne nanoconfined catalytic materials (A1, A2, A3) and graphidiyne on tetracycline in Example 1 of this invention. Figure 5 It was found that pure graphdiyne exhibited the lowest catalytic performance, with a tetracycline removal rate of only 28.09% after 12 min of reaction. When manganese monoxide nanoparticles were confined within the layered structure of graphdiyne nanosheets to form a manganese monoxide@graphdiyne nanoconfined catalytic material, its tetracycline degradation performance was significantly improved. After 12 min of reaction, the tetracycline removal rate of the composite material increased to over 60%. In particular, when the mass ratio of manganese chloride to graphdiyne was 16:1, the prepared manganese monoxide@graphdiyne nanoconfined catalytic material (A2) sample showed a tetracycline removal rate as high as 90.61% within 12 min, exhibiting the best catalytic performance. This significant improvement is attributed to the fact that the graphdiyne support not only effectively improved the dispersibility of manganese monoxide nanoparticles and exposed more active sites, but also that the strong interfacial coupling between it and manganese oxide synergistically promoted the activation of persulfate and the degradation of pollutants. Furthermore, when the amount of manganese chloride added was further increased (corresponding to sample A3), excessive manganese precursor could not be effectively anchored by graphdiyne, leading to the aggregation of manganese oxide nanoparticles, a reduction in active sites, and consequently a decrease in catalytic performance. These results indicate that by optimizing the mass ratio of manganese chloride to graphdiyne during preparation to between 8:1 and 32:1, particularly controlling it to 10–20:1, a manganese monoxide@graphdiyne nanoconfined catalytic material with suitable manganese oxide loading, optimal dispersibility, superior catalytic performance, and stable structure can be obtained.

[0051] Example 2 A method for treating organic pollutant wastewater using manganese monoxide@graphidyne nanoconfined catalytic material to activate persulfate (PMS) specifically uses the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 as a catalyst to degrade tetracycline wastewater with different pH values, including the following steps: Five portions (5 mg each) of the manganese monoxide@graphidiyne nanoconfined catalytic material (A2) prepared in Example 1 were accurately weighed and added to 50 mL of tetracycline aqueous solution with an initial concentration of 10 mg / L. The pH values ​​of the tetracycline solutions were adjusted to 3, 5, 7, 9, and 11, respectively. The solutions were mechanically stirred for 30 min in the dark to allow the tetracycline to reach adsorption-desorption equilibrium on the catalyst surface. Subsequently, 5 mg of permonosulfate (PMS) was added to each system to initiate a Fenton-like catalytic reaction and degrade the tetracycline wastewater for 12 min, thus completing the removal of tetracycline from the wastewater.

[0052] In the Fenton-like catalytic reaction, 3 mL samples were taken at specified time points (e.g., 0, 2 min, 4 min, 6 min, 8 min, 10 min, and 12 min) and immediately filtered through a 0.22 μm organic phase membrane to separate the catalyst. The concentration of tetracycline in the filtrate was determined using a UV-Vis spectrophotometer. Based on this, the degradation efficiency of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) for tetracycline in wastewater at different pH values ​​was calculated. The results are as follows: Figure 6 As shown.

[0053] Figure 6 This is a comparison of the degradation effects of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) on tetracycline under different pH conditions in Example 2 of this invention. Figure 6 It is evident that the manganese monoxide@graphidyne nanoconfined catalytic material of this invention can achieve tetracycline degradation over a wide pH range. In contrast, traditional Fenton reactions and some Fenton-like reactions cannot achieve efficient tetracycline degradation under pH conditions of 7-11. This indicates that the manganese monoxide@graphidyne nanoconfined catalytic material of this invention has broad practical applicability. This is mainly because the manganese monoxide@graphidyne nanoconfined catalytic material of this invention can confine the active site of manganese monoxide within graphidyne, and the active site is protected from pH interference by the graphidyne, ultimately resulting in the manganese monoxide@graphidyne nanoconfined catalytic material exhibiting superior adaptability.

[0054] Example 3 A method for treating organic pollutant wastewater using manganese monoxide@graphidyne nanoconfined catalytic material to activate persulfate (PMS) specifically uses the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 as a catalyst to degrade tetracycline wastewater under different coexisting ion conditions, including the following steps: Accurately weigh 5 mg of each of the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1, and add them to 50 mL of tetracycline aqueous solution with an initial concentration of 10 mg / L. Add anions (Cl-) to each tetracycline solution.- and H2PO4 - The concentrations of the tetracycline molecules in the solution were all 10 mmol / L. The mixture was mechanically stirred for 30 min in the dark to allow the tetracycline to reach adsorption-desorption equilibrium on the catalyst surface. Subsequently, 5 mg of permonosulfate (PMS) was added to each system to initiate a Fenton-like catalytic reaction, and the tetracycline wastewater was degraded for 12 min, thus completing the removal of tetracycline from the wastewater.

[0055] In the Fenton-like catalytic reaction, 3 mL samples were taken at specified time points (e.g., 0, 2 min, 4 min, 6 min, 8 min, 10 min, and 12 min) and immediately filtered through a 0.22 μm organic phase membrane to separate the catalyst. The concentration of tetracycline in the filtrate was determined using a UV-Vis spectrophotometer. Based on this, the degradation efficiency of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) for tetracycline in wastewater under different coexisting ion conditions was calculated. The results are as follows: Figure 7 As shown.

[0056] Figure 7 This is a comparison of the degradation effects of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) on tetracycline under different coexisting ion conditions in Example 3 of this invention. Figure 7 It can be seen that the manganese monoxide@graphidiyne nanoconfined catalytic material of the present invention can be used in Cl... - and H2PO4 - Even under coexisting conditions, it can still efficiently degrade tetracycline in water, which indicates that the manganese monoxide@graphitediyne nanoconfined catalytic material of the present invention has strong anti-interference ability, enabling it to treat various organic pollutants in wastewater and broadening its practical application scope.

[0057] Example 4 A method for treating organic pollutant wastewater using manganese monoxide@graphidyne nanoconfined catalytic material to activate persulfate (PMS) specifically uses the manganese monoxide@graphidyne nanoconfined catalytic material (A2) prepared in Example 1 as a catalyst to degrade tetracycline in actual water bodies, including the following steps: Three portions (5 mg each) of the manganese monoxide@graphidiyne nanoconfined catalytic material (A2) prepared in Example 1 were accurately weighed and added to 50 mL of tetracycline aqueous solution (ultrapure water, tap water, and lake water, respectively) with an initial concentration of 10 mg / L. The solutions were mechanically stirred for 30 min in the dark to allow tetracycline to reach adsorption-desorption equilibrium on the catalyst surface. Subsequently, 5 mg of permonosulfate (PMS) was added to each system to initiate a Fenton-like catalytic reaction, and the tetracycline wastewater was degraded for 12 min to complete the removal of tetracycline from the wastewater.

[0058] In the Fenton-like catalytic reaction, 3 mL samples were taken at specified time points (e.g., 0, 2 min, 4 min, 6 min, 8 min, 10 min, and 12 min) and immediately filtered through a 0.22 μm organic phase membrane to separate the catalyst. The concentration of tetracycline in the filtrate was determined using a UV-Vis spectrophotometer. Based on this, the degradation efficiency of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) for tetracycline in actual water bodies was calculated. The results are as follows: Figure 8 As shown.

[0059] Figure 8 This is a comparison chart showing the degradation effect of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) on tetracycline in different actual water bodies in Example 4 of this invention. Figure 8 It is known that the manganese monoxide@graphitediyne nanoconfined catalytic material of the present invention can efficiently degrade tetracycline in actual water bodies (tap water and lake water), which shows that the manganese monoxide@graphitediyne nanoconfined catalytic material has strong practical applicability.

[0060] In addition, the repeated degradation effect of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) on tetracycline wastewater was also investigated in this invention. The effect was basically the same as in Example 4, except that the manganese monoxide@graphitediyne nanoconfined catalytic material was used to activate persulfate multiple times and to degrade tetracycline wastewater (prepared with ultrapure water).

[0061] Figure 9 This is a comparison chart showing the repeated degradation effect of manganese monoxide@graphitediyne nanoconfined catalytic material (A2) on tetracycline in wastewater in Example 4 of this invention. Figure 9 It can be seen that after three repeated uses, the removal rate of tetracycline in wastewater by the manganese monoxide@graphitediyne nanoconfined catalytic material (A2) of the present invention is still as high as 79.47%. This shows that the manganese monoxide@graphitediyne nanoconfined catalytic material prepared by the present invention can still maintain high efficiency of persulfate activation and excellent pollutant degradation performance after multiple cycles of use, showing good structural stability and recyclability. This helps to reduce the catalyst consumption cost in actual water treatment process and provides convenience for its large-scale application.

[0062] The results above show that, compared with conventional manganese monoxide catalysts, the manganese monoxide@graphidyne nanoconfined catalyst used in this invention has advantages such as large specific surface area, numerous active sites, high loading, good dispersibility, high catalytic activity, and good stability. It is a novel manganese-based catalyst with excellent catalytic performance and stable structure. As a catalyst for activating persulfate, it can rapidly form a degradation system containing a large number of strongly oxidizing free radicals and non-free radicals, thereby achieving efficient degradation of different types of organic pollutants in wastewater. In addition, because the manganese monoxide nanoparticles are confined within graphidyne, the catalytic material of this invention experiences minimal loss of active components during repeated use and slow decay of catalytic performance. Furthermore, its excellent physicochemical stability ensures that it can be used multiple times to treat organic pollutant wastewater, significantly reducing the unit water treatment cost. This solves the economic and technical bottlenecks of homogeneous manganese catalysts and traditional supported manganese catalysts, which are either single-use or have short lifespans, and is beneficial for practical engineering applications. Furthermore, because the manganese monoxide nanoparticles are confined within graphdiyne, the catalytically active components are less affected by pH, allowing the manganese monoxide@graphdiyne catalyst to maintain excellent degradation performance for pollutants at pH values ​​of 3-11, significantly enhancing the practical applicability of this catalytic material. More importantly, in the manganese monoxide@graphdiyne nanoconfined catalytic material of this invention, the graphdiyne and manganese monoxide nanoparticles are not simply physically mixed, but form a strongly coupled interface. The highly conductive network of graphdiyne greatly promotes the efficiency of electron transfer from manganese monoxide to persulfate at the interface and accelerates the generation of active species. Simultaneously, the electronic structure modulation that may occur at the interface (such as changes in electron cloud density at active sites induced by electron transfer) further enhances the catalytic material's activation capacity for persulfate and its oxidative degradation efficiency for organic matter, exhibiting a synergistic catalytic effect of "1+1≥2". Therefore, the present invention utilizes manganese monoxide@graphitediyne nano-confined catalytic material to activate persulfate for treating organic pollutant wastewater. Benefiting from the material's abundant active sites, rapid electron transfer, and stable structure, the catalytic degradation system is not only highly efficient but also highly adaptable, exhibiting good degradation effects on a variety of organic pollutants. It has advantages such as simple process, convenient operation, high treatment efficiency, good removal effect, strong adaptability, and green environmental protection, and has important significance for promoting the deep purification of organic pollutant wastewater.

[0063] 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 treating organic pollutant wastewater using manganese monoxide@graphidiyne nanoconfined catalytic material by activating persulfate, characterized in that, The method uses manganese monoxide@graphidyne nanoconfined catalytic material as a catalyst to activate persulfate and degrade organic pollutant wastewater; the manganese monoxide@graphidyne nanoconfined catalytic material includes graphidyne nanosheets, and manganese monoxide nanoparticles are confined between the layered structures of the graphidyne nanosheets.

2. The method according to claim 1, characterized in that, The manganese monoxide nanoparticles in the aforementioned manganese monoxide@graphidiyne nanoconfined catalytic material have a particle size of 5 nm to 10 nm.

3. The method according to claim 2, characterized in that, The preparation method of the manganese monoxide@graphidyne nanoconfined catalytic material includes the following steps: S1. Mix graphdiyne, manganese salt, N,N-dimethylformamide and anhydrous ethanol, and disperse by ultrasonication to obtain a mixture; S2. The mixture obtained in step S1 is subjected to a solvothermal reaction to obtain the precursor material; S3. The precursor material obtained in step S2 is calcined under an inert atmosphere or a nitrogen atmosphere to obtain manganese monoxide@graphidiyne nanoconfined catalytic material.

4. The method according to claim 3, characterized in that, In step S1, the mass ratio of graphdiyne to manganese salt is 1:8 to 32.

5. The method according to claim 4, characterized in that, In step S1, the mass ratio of graphdiyne to manganese salt is 1:10 to 20.

6. The method according to claim 5, characterized in that, In step S1, the manganese salt is manganese chloride; the mass-to-volume ratio of the manganese salt to anhydrous ethanol is 0.4 g:30 mL; the volume ratio of N,N-dimethylformamide to anhydrous ethanol is 1:1; and the ultrasonic dispersion time is 30 min to 60 min. In step S2, the temperature of the solvothermal reaction is 120℃~180℃; the time of the solvothermal reaction is 12 h~48 h; after the solvothermal reaction is completed, the following treatment is also included: the product is vacuum filtered, washed with ethanol, and vacuum dried at 60℃ for 12 h~48 h to obtain the precursor material. In step S3, the calcination is performed by first heating to 450°C at a heating rate of 5°C / min and holding for 2 hours, then heating to 700°C at the same rate and holding for 1 hour to obtain manganese monoxide@graphidiyne nanoconfined catalytic material.

7. The method according to any one of claims 1 to 6, characterized in that, The degradation treatment of organic pollutant wastewater using manganese monoxide@graphitediyne nanoconfined catalytic material as a catalyst for activating persulfate includes the following steps: Manganese monoxide@graphitediyne nanoconfined catalytic material is mixed with organic pollutant wastewater, and persulfate is added to carry out a Fenton-like catalytic reaction to complete the degradation treatment of organic pollutant wastewater.

8. The method according to claim 7, characterized in that, The amount of manganese monoxide@graphidyne nanoconfined catalytic material added is 0.05 g to 0.2 g per liter of the organic pollutant wastewater; the amount of persulfate added is 0.1 g to 0.5 g per liter of the organic pollutant wastewater.

9. The method according to claim 8, characterized in that, The persulfate is permonosulfate; the organic pollutant includes antibiotics; the initial concentration of antibiotics in the wastewater is ≤10 mg / L; the antibiotic is tetracycline.

10. The method according to claim 7, characterized in that, The time for the Fenton-like catalytic reaction is 6 min to 18 min.

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