MnZn-F modified persulfate catalyst and preparation method and application thereof

Abstract

The invention discloses a MnZn-F modified persulfate catalyst as well as a preparation method and application thereof, and relates to the technical field of catalysts. The method comprises the following steps: performing fluorine modification on sodium silicate powder by adopting sodium fluoride under the action of a cross-linking agent and a template agent to obtain a fluorine-modified sodium silicate molecular sieve Si-F carrier; loading Mn < 2 + > and Zn < 2 + > on the fluorine-modified sodium silicate molecular sieve Si-F carrier, and granulating to obtain the MnZn-F modified persulfate catalyst. The prepared MnZn-F modified persulfate catalyst has the advantages of favorable catalytic activity, favorable COD (chemical oxygen demand) removal effect, low Mn and Zn dissolution tendency, favorable stability, low production cost and lower consumption, can be continuously reused, and does not cause secondary pollution. The MnZn-F modified persulfate catalyst can be widely applied to the field of oxidation treatment of organic wastewater.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically, to MnZn@F modified persulfate catalysts, their preparation methods, and applications. Background Technology

[0002] Persulfate (PS), as an oxidant, has a redox potential of 2.01V. Direct use for oxidizing organic matter in water is inefficient, but upon activation, it can generate sulfate free radicals (SO42-). - The redox potential of sulfuric acid radicals (SO4·) reaches 2.5–3.1 V, while that of hydroxyl radicals (·OH) is only 1.8–2.7 V, indicating that sulfuric acid radicals (SO4·) have a higher redox potential. - SO42- (·) has stronger oxidizing power and can oxidize most organic matter in wastewater. Furthermore, due to its preference for electron transfer reactions, SO42-... - • Longer lifespan; additionally, SO4 - It can react with water to form OH groups. Compared to OH groups, SO42-... - • has better oxidation performance, therefore, based on SO4 - Advanced oxidation technologies are receiving increasing attention.

[0003] Although based on SO4 - Advanced oxidation technologies have significant advantages, but SO4 - All of these require activation by persulfate to be produced. Common activation methods for persulfate include heat, light, alkali, and transition metal ions. However, all of these methods have certain drawbacks. For example, heat and light activation require additional equipment and energy consumption; alkali activation affects the pH of wastewater and has low efficiency; transition metal ions are added to the water body in the form of homogeneous catalysts, which has high activation efficiency, but there is not only the consumption and loss of transition metal ions, but also the transition metal ions are dissolved in the water body in the form of homogeneous catalysts, which are difficult to separate and remove after the reaction. This makes the water bodies containing transition metal ions (most of which are toxic) prone to secondary pollution of the environment.

[0004] To overcome the above-mentioned shortcomings, it is extremely urgent and important to develop a heterogeneous solid catalyst that can improve the activation efficiency of persulfate, reduce its own consumption, be reusable, and not cause secondary pollution.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a MnZn@F modified persulfate catalyst, its preparation method, and its application.

[0007] This invention is implemented as follows: In a first aspect, the present invention provides a method for preparing a MnZn@F modified persulfate catalyst, comprising: Sodium silicate powder was fluorinated with sodium fluoride under the action of a crosslinking agent and a template agent to obtain a fluorinated sodium silicate molecular sieve Si-F support. Mn was loaded onto the fluorine-modified sodium silicate molecular sieve Si-F support. 2+ and Zn 2+ MnZn@F modified molecular sieve catalyst was obtained; The MnZn@F modified molecular sieve catalyst was granulated to obtain a MnZn@F modified persulfate catalyst.

[0008] In an optional embodiment, the mass ratio of the sodium silicate powder, the sodium fluoride, the crosslinking agent, and the template agent is (30-50):(0.2-0.8):(0.035-0.065):0.1-1; And / or, the crosslinking agent is trimethylolpropane or trimethylolethane; And / or, the template agent comprises at least one of hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride.

[0009] In an optional embodiment, fluorine modification of the sodium silicate powder includes: mixing and reacting the sodium silicate powder, the sodium fluoride, and the crosslinking agent to obtain a gel; stirring the gel in a closed system to obtain crystals; and washing, first drying, and calcining the crystals to obtain a fluorine-modified sodium silicate molecular sieve Si-F support.

[0010] In an optional embodiment, obtaining the gel includes: adding water to a mixture of the sodium silicate powder, the sodium fluoride and the crosslinking agent to form a solution, stirring and reacting at 35-55°C for 60-120 min to form a gel solution, allowing it to stand at room temperature for 24-36 h, removing excess solvent from the surface of the gel, and obtaining the gel. And / or, the closed stirring reaction includes: stirring the gel in a closed environment at 110-180°C and 101-110 kPa for 1-6 days to obtain crystals, and then cooling to room temperature; And / or, the washing includes washing the crystals with deionized water; And / or, the temperature of the first drying is 50-70°C; And / or, the calcination includes calcination in an air atmosphere at 500-600°C for 3-6 hours.

[0011] In an optional embodiment, the fluorine-modified sodium silicate molecular sieve Si-F support is loaded by immersing it in a mixed solution of metal salts containing manganese and zinc salts, wherein the mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the mixed solution of metal salts is (2-5):3, wherein the concentration of the mixed solution of metal salts is 10%-20%, and the mass ratio of Mn:Zn in the mixed solution of metal salts is (100-160):1; Preferably, the loading process involves first immersing the fluorine-modified sodium silicate molecular sieve Si-F support in a mixed solution of manganese and zinc salts, stirring to obtain a suspension, and then subjecting the suspension to a second drying and heat treatment to allow the Mn to react. 2+ Zn 2+ The fluorine-modified sodium silicate molecular sieve Si-F support was loaded to obtain the MnZn@F modified molecular sieve catalyst.

[0012] In an optional embodiment, the fluorine-modified sodium silicate molecular sieve Si-F support is mixed with the metal salt mixed solution and then stirred at 30-50°C for 4-8 hours to obtain the suspension; And / or, the second drying temperature is 100-120℃, and the drying time is 24-36h; And / or, the heat treatment temperature is 150-300℃, and the heat treatment time is 2-4h; And / or, the manganese salt includes at least one of MnCl2, MnSO4 and Mn(NO3)2; And / or, the zinc salt includes at least one of ZnCl2, ZnSO4 and Zn(NO3)2.

[0013] In an optional embodiment, the granulation includes wet granulation or dry granulation; Preferably, the wet granulation process includes: mixing the MnZn@F modified molecular sieve catalyst and a binder, wherein the mass ratio of the catalyst to the binder is 1:(0.04-0.08); after granulation, the mixture is sieved through a 3-10 mesh screen to obtain wet particles; and the wet particles are dried at 40-60°C to obtain spherical MnZn@F modified persulfate catalyst with a particle size of 2-4 mm.

[0014] In an optional embodiment, before immersing the fluorine-modified sodium silicate molecular sieve Si-F support in a mixed solution of manganese and zinc salts, the fluorine-modified sodium silicate molecular sieve Si-F support is further soaked and acid-washed with an acidic solution of pH 1-3 for 2-4 hours, then filtered and washed with deionized water. Preferably, the acidic solution includes hydrochloric acid, sulfuric acid, or nitric acid.

[0015] Secondly, the present invention provides a MnZn@F modified persulfate catalyst, which is prepared by the preparation method of MnZn@F modified persulfate catalyst as described in any of the foregoing embodiments.

[0016] Thirdly, the present invention provides the application of the MnZn@F modified persulfate catalyst as described in the foregoing embodiments as a persulfate catalyst in the oxidation treatment of organic wastewater.

[0017] The present invention has the following beneficial effects: First, the method for preparing the MnZn@F modified persulfate catalyst provided by this invention involves fluorinating sodium silicate powder with sodium fluoride under the action of a crosslinking agent, followed by loading Mn... 2+ and Zn 2+ The MnZn@F modified persulfate catalyst is then obtained through granulation. In this invention, sodium silicate molecular sieve is used as the support. Sodium silicate molecular sieve has extremely high specific surface area and good thermal stability (withstanding temperatures above 1000℃). By fluorinating the sodium silicate molecular sieve, some oxygen atoms (O) bonded to Si atoms are replaced by fluorine atoms (F), forming an F-doped molecular sieve, which increases the stability of the material. This is because fluorine modification forms Si-F bonds. Since F has higher electronegativity than O, is difficult to oxidize, and is not easily deformed, it belongs to the "hard base" category. Si, on the other hand, has a high charge density and a small ionic radius, belonging to the "hard acid" category. The "hard base" F... - With "hard acid" Si 4+ Due to electrostatic interactions, they readily combine to form a stable complex, SiF6. 2- Compared to the original Si-O bonds, this enhances the stability of the catalyst, avoids the problem of catalyst shedding after long-term use, and has a longer service life.

[0018] Secondly, the F-modified molecular sieve was then loaded with metal Mn. 2+ and Zn 2+ Among these methods, manganese (Mn) modification provides "active sites" for reactants, offering electron transfer opportunities and promoting the reaction. It catalyzes the conversion of persulfate into sulfate radicals, which can oxidize most organic matter in water, thus improving catalytic oxidation efficiency. Zn modification alters the outer electronic structure of Mn and the structure of Mn atoms, resulting in a more uniform catalytic reaction, better and longer-lasting catalytic performance, and significantly reduced Mn addition, thus lowering costs.

[0019] Finally, the modified MnZn@F molecular sieve catalyst is further granulated to transform it into spherical particles with a fixed particle size (2-4 mm). Compared to molecular sieves, spherical particles have a large surface area, which facilitates the rapid physical adsorption of more pollutants in the water onto the catalyst surface, thereby promoting the catalytic oxidation reaction. On the other hand, they can be fixedly filled in the catalytic reaction device, can be reused repeatedly, and will not be lost due to wastewater flow, reducing catalyst loss and consumption. They also avoid the problem of traditional homogeneous catalysts being difficult to separate from water. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a graph showing the COD data of the influent and effluent from the catalyst provided in Example 1 of the present invention after three months of continuous operation. Figure 2 The curve and fitting curve of COD removal rate over time for the catalyst provided in Example 1 of this invention after 300 days of continuous operation; Figure 3 This is a graph showing the COD data of the influent and effluent from the catalysts provided in Example 1 and Comparative Example 1 of the present invention after three months of continuous operation. Figure 4 Here is a scanning electron microscope image of the catalyst from Example 1 of this invention; Figure 5 This is a scanning electron microscope image of the catalyst in Comparative Example 4 of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0023] This invention provides a method for preparing a MnZn@F modified persulfate catalyst, comprising: fluorinating sodium silicate powder with sodium fluoride under the action of a crosslinking agent and a template agent to obtain a fluorinated sodium silicate molecular sieve Si-F support; and loading Mn onto the fluorinated sodium silicate molecular sieve Si-F support. 2+ and Zn 2+MnZn@F modified molecular sieve catalyst was obtained; the MnZn@F modified molecular sieve catalyst was granulated to obtain MnZn@F modified persulfate catalyst.

[0024] In this invention, sodium silicate powder and a template agent react to form a pure silicon-based molecular sieve. Using the sodium silicate molecular sieve as a carrier, it possesses extremely high specific surface area and good thermal stability (withstanding temperatures above 1000℃). During the molecular sieve preparation process, sodium fluoride and a crosslinking agent are added to fluorine-modify the sodium silicate molecular sieve, replacing some oxygen atoms (O) bonded to Si atoms with fluorine atoms (F), forming an F-doped molecular sieve, thus increasing the material's stability. This is because fluorine modification forms Si-F bonds. Since F has higher electronegativity than O, is difficult to oxidize, and is not easily deformed, it belongs to the category of "hard bases," while Si has a high charge density and a small ionic radius, belonging to the category of "hard acids." The "hard base" F... - With "hard acid" Si 4+ Due to electrostatic interactions, they readily combine to form a stable complex, SiF6. 2- Compared to the original Si-O bonds, this enhances the stability of the catalyst, avoids the problem of catalyst shedding after long-term use, and has a longer service life.

[0025] Subsequently, by loading the metal Mn 2+ and Zn 2+ Among these processes, manganese (Mn) modification provides "active sites" for reactants, offering electron transfer opportunities and promoting the reaction. It can catalyze the conversion of persulfate into sulfate radicals, which can oxidize most organic matter in water, thereby improving catalytic oxidation efficiency. Meanwhile, zinc (Zn) alters the outer electronic structure of Mn and the structure of Mn atoms, resulting in a more uniform catalytic reaction, better and longer-lasting catalytic performance. Simultaneously, it significantly reduces the need for Mn addition, lowering costs.

[0026] The modified MnZn@F molecular sieve catalyst is then granulated to transform it into spherical particles with a fixed particle size (2-4 mm). Compared to molecular sieves, spherical particles have a large surface area, which facilitates the rapid physical adsorption of more pollutants in the water onto the catalyst surface, thereby promoting the catalytic oxidation reaction. Furthermore, they can be fixedly filled in the catalytic reaction device, can be reused repeatedly, and will not be lost due to wastewater flow, reducing catalyst loss and consumption. They also avoid the problem of traditional homogeneous catalysts being difficult to separate from water.

[0027] The preparation method of the MnZn@F modified persulfate catalyst provided by this invention specifically includes the following steps: S1. Sodium silicate powder is fluorinated with sodium fluoride under the action of a crosslinking agent and a template agent to obtain a fluorinated sodium silicate molecular sieve Si-F support.

[0028] Fluorine modification of sodium silicate powder includes: mixing sodium silicate powder, sodium fluoride, crosslinking agent and template agent to obtain a gel, stirring the gel in a closed system to obtain crystals; washing, first drying and calcining the crystals to obtain fluorine-modified sodium silicate molecular sieve Si-F support.

[0029] In this invention, a mixture of sodium silicate powder, sodium fluoride, crosslinking agent, and template agent is added to water to form a solution, and stirred at 35-55°C for 60-120 min to form a gel. After standing at room temperature for 24-36 h, excess solvent is removed from the gel surface to obtain the gel. The mass ratio of sodium silicate powder, sodium fluoride, crosslinking agent, and template agent is (30-50):(0.2-0.8):(0.035-0.065):0.1-1. The crosslinking agent is trimethylolpropane or trimethylolethane, and the template agent includes at least one of hexadecyltrimethylammonium bromide (CTAB) and hexadecyltrimethylammonium chloride (CTAC). In this invention, by adding water to a mixture of sodium silicate powder, sodium fluoride, crosslinking agent, and template agent to form a solution, sodium silicate readily undergoes hydrolysis / condensation in the aqueous solution to form oligomeric silicic acid, while the crosslinking agent contains OH groups. - Oligomeric silicates readily combine with crosslinking agents, facilitating subsequent gel formation. F⁻ combines with sodium silicate to form Si-F bonds, slowing the condensation rate and preventing the rapid formation of amorphous precipitates, thus providing a stable precursor for subsequent crystallization. Crosslinking agents promote intermolecular crosslinking, forming a three-dimensional network structure, ultimately resulting in a uniform gel system. This disperses the sodium silicate silicon source and sodium fluoride within the three-dimensional network, providing a uniform chemical environment for subsequent crystal growth.

[0030] The gel was subjected to a closed-loop stirring reaction at 110-180℃ and 101-110KPa for 1-6 days to obtain crystals, which were then cooled to room temperature. By reacting the gel in a closed environment, the amorphous or low-crystallinity substances in the gel were transformed into solids with a definite crystal structure.

[0031] The crystals are washed with deionized water, then dried at 50-70℃, followed by calcination in air at 500-600℃ for 3-6 hours. Washing reduces ionic impurities (such as Na⁺, F⁻, etc.) in the product, preventing structural defects caused by residual impurities during subsequent drying or calcination. The first drying removes physically adsorbed water, fixing the crystal morphology and facilitating subsequent calcination. It also reduces crystal fragmentation caused by rapid water evaporation during calcination. Subsequent calcination removes organic residues from the pores, opens blocked pores, and improves the crystallinity and structural stability of the crystals, enabling them to withstand higher temperatures and stronger chemical environments in subsequent applications (such as adsorption and catalysis).

[0032] S2. The fluorine-modified sodium silicate molecular sieve Si-F support is soaked and acid-washed in an acidic solution with a pH of 1-3 for 2-4 hours, then filtered and washed with deionized water.

[0033] In this invention, acid washing can remove some residual inorganic impurities from the surface and channels of the molecular sieve, thereby increasing the effective surface area of ​​the channels and facilitating the uniform distribution of metals in the subsequent process. The acidic solution includes, but is not limited to, hydrochloric acid, sulfuric acid, or nitric acid.

[0034] S3, Mn loaded onto fluorine-modified sodium silicate molecular sieve Si-F support 2+ and Zn 2+ MnZn@F modified molecular sieve catalyst was obtained.

[0035] Load Mn 2+ and Zn 2+ There are various methods, and this invention provides a typical but non-limiting example in which the fluorine-modified sodium silicate molecular sieve Si-F support is loaded by immersing it in a mixed solution of metal salts containing manganese and zinc salts.

[0036] Specifically, the fluorine-modified sodium silicate molecular sieve Si-F support is first immersed in a mixed solution of manganese and zinc salts, and the reaction is carried out at 30-50℃ with stirring for 4-8 hours. The resulting suspension is then subjected to a second drying and heat treatment to allow the Mn... 2+ Zn 2+ MnZn@F modified molecular sieve catalysts were obtained by loading them onto a fluorine-modified sodium silicate molecular sieve Si-F support.

[0037] The mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the metal salt mixed solution is (2-5):3, wherein the concentration of the metal salt mixed solution is 10%-20%, and the mass ratio of Mn:Zn in the metal salt mixed solution is (100-160):1; the manganese salt includes, but is not limited to, at least one of MnCl2, MnSO4 and Mn(NO3)2; the zinc salt includes, but is not limited to, at least one of ZnCl2, ZnSO4 and Zn(NO3)2.

[0038] As can be seen from the Mn:Zn mass ratio in this invention, the amount of Mn added is much greater than the amount of Zn added. This is mainly because Mn is the transition metal that plays the primary catalytic role, while the trace amount of Zn mainly serves an auxiliary role for Mn. One aspect is to enhance the catalytic performance of Mn, primarily by altering the outer electronic structure of Mn and increasing the number of empty orbitals. This enhances the catalytic activity of Mn during the persulfate reaction. 2+ Adsorption of S2O8 2-The interaction force of the O-O peroxide bond in the ion reduces the bond energy of the O-O peroxide bond, accelerates the breaking of the O-O bond, and promotes the S2O8 bond. 2- Converted to sulfate radical SO4 - The reaction occurs, improving the catalytic performance of Mn. On the other hand, Zn allows Mn to be better embedded in the support surface, preventing loss and detachment, thus preventing Mn aggregation and limiting Mn migration on the support surface. This results in a more uniform catalytic reaction and better performance, while significantly reducing the amount of Mn needed and lowering costs. Finally, Zn alters the atomic structure of Mn, shrinking the Mn-Mn lattice spacing, which is beneficial for SO42-. - ▪ Desorption and dissociation leave "active sites" to facilitate the next round of continuous reaction, thus ensuring that the catalyst's catalytic performance is more sustainable and long-lasting.

[0039] The catalytic mechanism of metallic manganese (Mn) is as follows: Reactants near Mn 2+ At that time, the electron cloud of the reactants will affect Mn 2+ The d orbitals of Mn generate a strong electrostatic repulsion, leading to Mn 2+ (Electron configuration [Ar]3d) 5 When five d orbitals of equal energy split (e.g., into two groups, t2g and eg), under the influence of repulsive forces, Mn 2+ Electrons in Mn are arranged in a high-spin or low-spin configuration for bonding. 2+ Hybridize the elevated eg orbital (which interacts strongly with reactants) with the empty outer 4s and 4p orbitals (e.g., sp orbitals) 3 d 2 This forms new empty hybrid orbitals, which can provide "active sites" for reactants, making them easier to be adsorbed and activated. This provides a "site" for electron transfer in the reaction, that is, to participate in the catalytic reaction without being consumed by the reactants themselves.

[0040] Mn 2+ The specific process of the catalytic mechanism: (1) Adsorption process: When reactant molecules in water (such as S2O8) 2- When Mn in the catalyst diffuses to the catalyst surface (including organic matter), the Mn in the catalyst... 2+ The empty orbitals of S2O8 are chemically bonded to molecules / ions, making S2O8 2- Organic matter (such as CH3-COOH) is strongly adsorbed onto specific "active sites" on the catalyst surface.

[0041] (2) Catalytic activation: Mn 2+ Empty orbitals readily absorb S2O8 2- The electron pairs of OO in S2O8 make S2O8 2-Upon activation at the "active site," it dissociates into sulfate radicals (SO4). - ·) and high-valence active species Mn 3+ The reaction equation is as follows (1-1): (1-1) (3) Oxidation reaction: SO4 - • Upon contact with organic matter on the catalyst surface, a chain reaction occurs, generating organic intermediate free radicals. These intermediate free radicals then continue to react with SO4. - The reaction proceeds, ultimately producing CO2 and SO4. 2- As shown in reaction (1-2); simultaneously, it desorbs from the "active site" of the catalyst, freeing up the "active site", which can then be recycled for the next round of catalysis of S2O8. 2- The reaction.

[0042] SO4 - +CH3-COOH→·CH2-COOH+SO4 2- +H + (1-2) 7SO4 - ·+·CH2-COOH+2H2O→2CO2+7H + +7SO4 2- (1-3) (4) Catalytic cycle: high-valence active species Mn 3+ It has strong oxidizing properties and will oxidize organic matter into free radicals. The free radicals generated will undergo the reactions described above (1-3). Mn 3+ It is restored to its initial valence state Mn 2+ It can continue to catalyze the reaction in a cyclical manner, and no manganese is consumed during the entire reaction process.

[0043] Mn 3+ +CH3-COOH→Mn 2+ +·CH2-COOH+H + (1-4) This invention improves the catalytic performance of MnZn@F modified persulfate catalysts by loading Mn and Zn in a specific ratio onto the surface of a fluorine-modified sodium silicate molecular sieve Si-F support, resulting in more durable performance and reduced production costs.

[0044] Furthermore, in this invention, the second drying temperature is 100-120℃ and the drying time is 24-36h; the heat treatment temperature is 150-300℃ and the heat treatment time is 2-4h.

[0045] The second drying process can dry the free water in the suspension, preparing it for subsequent heat treatment. The heat treatment is carried out at a temperature of 150-300℃, which can fix Mn and Zn in the pores and surface of the fluorine-modified sodium silicate molecular sieve Si-F support, making their binding effect better and preventing Mn and Zn from dissolving during subsequent catalysis.

[0046] S4. Granulate the MnZn@F modified molecular sieve catalyst to obtain a spherical MnZn@F modified persulfate catalyst with a particle size of 2-4 mm.

[0047] This invention granulates the MnZn@F modified persulfate catalyst, thereby controlling the particle size of the final product. This makes it easy to fix within the oxidation reactor, allowing for repeated use and preventing loss during catalysis due to wastewater flow. It also avoids the problem of separation between traditional homogeneous catalysts and water.

[0048] There are various granulation methods, including but not limited to wet granulation or dry granulation.

[0049] This invention describes a typical but not limited wet granulation method, specifically comprising: mixing a MnZn@F modified molecular sieve catalyst and a binder, wherein the mass ratio of catalyst to binder is 1:(0.04-0.08), and the binder includes, but is not limited to, polyvinyl acetate emulsion; after granulation, the mixture is sieved through a 3-10 mesh sieve to obtain wet particles; and the wet particles are dried at 40-60°C to obtain spherical MnZn@F modified persulfate catalyst with a particle size of 2-4 mm.

[0050] This invention provides a MnZn@F modified persulfate catalyst, which is prepared using the aforementioned method for preparing MnZn@F modified persulfate catalysts. The prepared MnZn@F modified persulfate catalyst exhibits good catalytic activity, excellent COD removal efficiency, and minimal dissolution of the active components Mn and Zn, resulting in good stability. The catalyst also has low production costs, is virtually non-consumable, can be repeatedly used, and does not cause secondary pollution. This MnZn@F modified persulfate catalyst can be widely used in the preparation of persulfate catalysts.

[0051] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0052] Example 1 This embodiment provides a method for preparing a MnZn@F modified persulfate catalyst, which includes the following steps: S1. Sodium silicate powder, sodium fluoride, crosslinking agent (trimethylolpropane), and template agent (hexadecyltrimethylammonium bromide) were mixed in a mass ratio of 30:0.2:0.035:0.2, and water was added to form a solution. The mixture was stirred at 45°C for 90 min to form a gel. After standing at room temperature for 30 h, excess solvent was removed from the gel surface to obtain a gel. The gel was then stirred in a sealed environment at 140°C and 105 kPa for 4 days to obtain crystals, which were then cooled to room temperature. The crystals were washed with deionized water, then dried at 60°C, and finally calcined in air at 550°C for 4.5 h to obtain a fluorine-modified sodium silicate molecular sieve Si-F support.

[0053] S2. The fluorine-modified sodium silicate molecular sieve Si-F support was soaked and acid-washed for 3 hours with hydrochloric acid solution at pH 2, then filtered and washed with deionized water.

[0054] S3. The fluorine-modified sodium silicate molecular sieve Si-F support was immersed in a mixed solution of manganese and zinc salts, and the reaction was stirred at 40°C for 6 hours. A suspension was obtained by stirring, and the suspension was subjected to a second drying at 115°C for 30 hours, followed by heat treatment at 230°C for 3 hours to allow the Mn... 2+ Zn 2+ MnZn@F modified molecular sieve catalysts were obtained by loading them onto a fluorine-modified sodium silicate molecular sieve Si-F support.

[0055] The mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the metal salt mixed solution is 4:3, the concentration of the metal salt mixed solution is 15%, and the mass ratio of Mn:Zn in the metal salt mixed solution is 150:1; the manganese salt is MnCl2; and the zinc salt is ZnCl2.

[0056] S4. Mix the MnZn@F modified molecular sieve catalyst and binder (polyvinyl acetate emulsion) at a mass ratio of 1:0.06, granulate, and then sieve through a 6-mesh sieve to obtain wet particles; dry the wet particles at 50°C to obtain spherical MnZn@F modified persulfate catalyst with a particle size of 2-4 mm.

[0057] Example 2 This embodiment provides a method for preparing a MnZn@F modified persulfate catalyst, which includes the following steps: S1. Sodium silicate powder, sodium fluoride, crosslinking agent (trimethylolpropane), and template agent (hexadecyltrimethylammonium chloride) were mixed in a mass ratio of 50:0.8:0.065:1, and water was added to form a solution. The mixture was stirred at 35°C for 120 min to form a gel. After standing at room temperature for 36 h, excess solvent was removed from the gel surface to obtain a gel. The gel was then subjected to a closed-loop stirring reaction at 110°C and 101 kPa for 6 days to obtain crystals, which were then cooled to room temperature. The crystals were washed with deionized water, then dried at 50°C, and finally calcined in air at 500°C for 6 h to obtain a fluorine-modified sodium silicate molecular sieve Si-F support.

[0058] S2. The fluorine-modified sodium silicate molecular sieve Si-F support was soaked and acid-washed with sulfuric acid solution at pH 1 for 4 hours, then filtered and washed with deionized water.

[0059] S3. The fluorine-modified sodium silicate molecular sieve Si-F support was immersed in a mixed solution of manganese and zinc salts, and the reaction was stirred at 30°C for 8 hours. A suspension was obtained by stirring, and the suspension was subjected to a second drying at 110°C for 36 hours, followed by heat treatment at 150°C for 4 hours to allow the Mn... 2+ Zn 2+ MnZn@F modified molecular sieve catalysts were obtained by loading them onto a fluorine-modified sodium silicate molecular sieve Si-F support.

[0060] The mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the metal salt mixed solution is 2:3, the concentration of the metal salt mixed solution is 10%, and the mass ratio of Mn:Zn in the metal salt mixed solution is 100:1; the manganese salt is MnSO4; and the zinc salt is ZnSO4.

[0061] S4. Mix the MnZn@F modified molecular sieve catalyst and binder (polyvinyl acetate emulsion) at a mass ratio of 1:0.04, granulate, and then sieve through a 5-mesh sieve to obtain wet particles; dry the wet particles at 40℃ to obtain spherical MnZn@F modified persulfate catalyst with a particle size of 2-4 mm.

[0062] Example 3 This embodiment provides a method for preparing a MnZn@F modified persulfate catalyst, which includes the following steps: S1. Sodium silicate powder, sodium fluoride, crosslinking agent (trimethylolpropane), and template agent (hexadecyltrimethylammonium bromide) were mixed in a mass ratio of 40:0.4:0.05:0.8, and water was added to form a solution. The mixture was stirred at 55°C for 60 min to form a gel. After standing at room temperature for 24 h, excess solvent was removed from the gel surface to obtain a gel. The gel was then stirred in a sealed environment at 180°C and 110 kPa for 3 days to obtain crystals, which were then cooled to room temperature. The crystals were washed with deionized water, then dried at 70°C, and finally calcined in air at 600°C for 3 h to obtain a fluorine-modified sodium silicate molecular sieve Si-F support.

[0063] S2. The fluorine-modified sodium silicate molecular sieve Si-F support was soaked and acid-washed for 2 hours in a nitric acid solution with a pH of 3, then filtered and washed with deionized water.

[0064] S3. The fluorine-modified sodium silicate molecular sieve Si-F support was immersed in a mixed solution of manganese and zinc salts, and the reaction was stirred at 50°C for 4 hours. A suspension was obtained by stirring, and the suspension was subjected to a second drying at 120°C for 24 hours, followed by heat treatment at 300°C for 2 hours to allow the Mn... 2+ Zn 2+ MnZn@F modified molecular sieve catalysts were obtained by loading them onto a fluorine-modified sodium silicate molecular sieve Si-F support.

[0065] The mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the metal salt mixed solution is 5:3, the concentration of the metal salt mixed solution is 20%, and the mass ratio of Mn:Zn in the metal salt mixed solution is 160:1; the manganese salt is Mn(NO3)2; and the zinc salt is Zn(NO3)2.

[0066] S4. Mix the MnZn@F modified molecular sieve catalyst and binder (polyvinyl acetate emulsion) at a mass ratio of 1:0.08, granulate, and then sieve through an 8-mesh sieve to obtain wet particles; dry the wet particles at 60℃ to obtain spherical MnZn@F modified persulfate catalyst with a particle size of 2-4 mm.

[0067] Example 4 This embodiment is basically the same as Embodiment 1, except that the mass ratio of sodium silicate powder, sodium fluoride, crosslinking agent and template agent in this embodiment is 10:0.2:0.035:1.3.

[0068] Example 5 This embodiment is basically the same as Embodiment 1, except that the mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the metal salt mixed solution is 2:1, the concentration of the metal salt mixed solution is 15%, and the mass ratio of Mn:Zn in the metal salt mixed solution is 130:1.

[0069] Example 6 This embodiment is basically the same as Embodiment 1, except that the mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the metal salt mixed solution is 4:3, the concentration of the metal salt mixed solution is 15%, and the mass ratio of Mn:Zn in the metal salt mixed solution is 50:1.

[0070] Comparative Example 1 This comparative example provides an unmodified catalyst, which is prepared without doping with F, Mn, and Zn. The specific preparation method includes: S1. Sodium silicate powder and template agent (hexadecyltrimethylammonium bromide) are mixed at a mass ratio of 30:0.2, and water is added to form a solution. The mixture is stirred at 45°C for 90 min to form a gel. After standing at room temperature for 30 h, excess solvent is removed from the surface of the gel to obtain a gel. The gel is then stirred in a sealed environment at 140°C and 105 kPa for 4 days to obtain crystals. After cooling to room temperature, the crystals are washed with deionized water, then dried at 60°C, and finally calcined in air at 550°C for 4.5 h to obtain the final product.

[0071] S2 is the same as S2 in Example 1.

[0072] S3 is the same as S4 in Example 1.

[0073] Comparative Example 2 This comparative example provides a Mn-Zn catalyst that has not undergone F modification. The catalyst is prepared without F doping during the process, and the specific preparation method includes: S1. Sodium silicate powder and template agent (hexadecyltrimethylammonium bromide) were mixed at a mass ratio of 30:0.2, and water was added to form a solution. The mixture was stirred at 45°C for 90 min to form a gel. After standing at room temperature for 30 h, excess solvent was removed from the surface of the gel to obtain a gel. The gel was then stirred in a sealed container at 140°C and 105 kPa for 4 days to obtain crystals. The crystals were then cooled to room temperature. The crystals were washed with deionized water, then dried at 60°C, and finally calcined in air at 550°C for 4.5 h.

[0074] S2-S4 are the same as S2-S4 in Example 1.

[0075] Comparative Example 3 This comparative example provides an F-Zn catalyst that has not undergone Mn modification and is prepared without Mn doping. The specific preparation method includes: S1-S2 are the same as S1-S2 in Example 1.

[0076] S3. The fluorine-modified sodium silicate molecular sieve Si-F support was immersed in a zinc salt solution and stirred at 40°C for 6 hours. A suspension was obtained by stirring and then subjected to a second drying at 115°C for 30 hours, followed by heat treatment at 230°C for 3 hours to allow the Zn... 2+ Zn@F modified molecular sieve catalysts were obtained by loading the catalysts onto a fluorine-modified sodium silicate molecular sieve Si-F support.

[0077] The mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the zinc salt solution is 4:3, the concentration of the zinc salt solution is 15%, and the zinc salt is ZnCl2.

[0078] S4 is the same as S4 in Example 1.

[0079] Comparative Example 4 This comparative example provides an F-Mn catalyst that has not undergone Zn modification and is prepared without Mn doping. The specific preparation method includes: S1-S2 are the same as S1-S2 in Example 1.

[0080] S3. The fluorine-modified sodium silicate molecular sieve Si-F support was immersed in a manganese salt solution and stirred at 40°C for 6 hours. A suspension was obtained by stirring and then subjected to a second drying at 115°C for 30 hours, followed by heat treatment at 230°C for 3 hours to allow the Mn... 2+ Mn@F modified molecular sieve catalysts were obtained by loading them onto a fluorine-modified sodium silicate molecular sieve Si-F support.

[0081] The mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the zinc salt solution is 4:3, the concentration of the zinc salt solution is 15%, and the manganese salt is MnCl2.

[0082] S4 is the same as S4 in Example 1.

[0083] Comparative Example 5 This comparative example provides an F catalyst that has not been modified with Mn and Zn, and its preparation process does not involve doping with Mn and Zn. The specific preparation method includes: S1-S2 are the same as S1-S2 in Example 1.

[0084] S3 is the same as S4 in Example 1.

[0085] Comparative Example 6 This comparative example is basically the same as Example 1, except that Mn in Example 1 is replaced with Mo in this comparative example.

[0086] Comparative Example 7 This comparative example is basically the same as Example 1, except that Zn in Example 1 is replaced with Cr in this comparative example.

[0087] Comparative Example 8 This comparative example is basically the same as Example 1, except that the acid washing step S2 of Example 1 is omitted in this comparative example.

[0088] Comparative Example 9 This comparative example is basically the same as Example 1, except that the granulation step S4 of Example 1 is omitted in this comparative example.

[0089] Experimental Example 1 The catalyst samples prepared in Examples 1-6 and Comparative Examples 1-9 were respectively packed into oxidation reactors. The catalyst packing ratio (the ratio of packing volume to the effective reactor volume) was 50%. A certain smelting wastewater (pH=6-8, SO42-) was continuously introduced into the reactor. 2- =40000-55000 mg / L, Cl - =2000-3000mg / L, COD=800-1120mg / L, Na + =20000-29500 mg / L, F - =0.1-0.2 mg / L, Mn 2+ =0.1-0.22 mg / L, Zn 2+ =0.05-0.1 mg / L), while continuously adding sodium persulfate solution with a concentration of 35%, controlling the sodium persulfate dosage to 600 mg / L (600 mg sodium persulfate per L of water), controlling the hydraulic retention time to 2 hours, continuous operation at room temperature, and testing the influent and effluent COD and F every 3 days. - Mn 2+ Zn 2+ Concentration, with the data for each indicator within the first 30 days as follows: Figures 1-2 Tables 1-2: Table 1. COD Statistics of Influent and Effluent in Different Examples over the First 30 Days

[0090] From the table above and Figure 1It can be seen that, during three months of continuous operation, the catalysts prepared in Examples 1-4 maintained a stable effluent COD of less than 60 mg / L when the influent COD fluctuated within the range of 800-1120 mg / L, meeting the standard requirements, indicating that the catalysts had good catalytic oxidation effect. In Examples 5-6, the Mn:Zn mass ratio was outside the range specified in this application, resulting in effluent CODs exceeding 100 mg / L, which failed to meet the standard requirements.

[0091] From the table above and Figure 3 It can be seen that the effluent COD of Comparative Example 1 and the unmodified catalyst and the catalyst without Mn and Zn modification provided in Comparative Example 1 are significantly higher, while the removal rate is significantly lower. The main reason is that COD degradation relies solely on the oxidation effect of sodium persulfate itself, that is, the oxidizing power is weak when there is no catalytic effect. However, after the catalyst of Example 1 of this application was modified, sodium persulfate was catalyzed to produce SO4. - Its oxidation activity is significantly enhanced, meaning that the COD removal effect is significantly improved.

[0092] As can be seen from the table above, in Comparative Example 2, no F modification was performed, and the catalytic activity was almost unaffected, but the stability of the catalyst may be relatively low. In Comparative Example 3, which was not modified with Mn, the catalytic effect was slightly higher than that of the unmodified catalyst in Comparative Example 1, but the average removal rate was only 57.82%, which was significantly lower than that in Example 1. This indicates that the catalyst without Mn modification has a significantly reduced catalytic performance.

[0093] Depend on Figure 4 , Figure 5 It can be seen that Comparative Example 4, which was not modified with Zn, showed a significant decrease in catalytic effect, with an average COD removal rate of only 68.23%. This indicates that Zn modification can better embed Mn on the support surface, making it less prone to loss and detachment, preventing Mn aggregation, limiting the migration of Mn on the support surface, and making the catalytic reaction of the catalyst more uniform and the catalytic effect better.

[0094] Comparative Example 5, which only underwent F modification, showed a slightly better catalytic effect than the unmodified catalyst in Comparative Example 1, but was significantly worse than Comparative Examples 2-4. This indicates that F modification alone can only improve the stability of the catalyst structure, while without metal Mn and Zn modification, the catalyst activity cannot be improved.

[0095] Comparative Examples 6 and 7 show that the COD of the effluent was significantly higher than that of Example 1, and the removal rate was significantly lower, indicating that the catalytic effect of Mo replacing Mn and Cr replacing Zn was significantly weaker than that of Mn and Zn.

[0096] Comparative Examples 8 and 9 show that omitting the acid washing and granulation steps has little impact on the catalyst's activity, but the catalyst may contain impurities that could affect water quality.

[0097] Table 2. Influent and Effluent F in the first 30 days for different examples - Mn 2+ Zn 2+ Concentration statistics table

[0098] As shown in Table 2 above, only Comparative Examples 2, 8, and 9 showed an increase in effluent ion concentration. In Comparative Example 2, due to the lack of F modification, the catalyst's structural stability was poor. During long-term operation, active components such as Mn and Zn in the catalyst detached and dissolved into the water, leading to an increase in ionic impurities. In Comparative Examples 8 and 9, the lack of acid washing or granulation steps in the catalyst preparation process may have introduced a small amount of impurities into the final catalyst material. Furthermore, the ungranulated catalyst easily lost and dissolved into the water, resulting in an increase in ionic impurities. In addition, the F concentration in the effluent of the other examples was significantly higher. - Mn 2+ Zn 2+ The concentrations were almost equal to the influent ion concentrations, indicating that F, Mn, and Zn in the catalyst did not detach or dissolve from the catalyst, suggesting that the catalyst has good stability within 3 months of continuous operation.

[0099] Experimental Example 2 This experiment compares the amount of Mn in the catalysts of Example 1 and Comparative Example 4 while keeping the COD removal rate and the mass of the support constant.

[0100] Table 3. Statistics on the amount of Mn used in the catalysts of Examples 1 and 4

[0101] It can be seen that when the catalytic effects of the catalysts are equal (COD removal rates both reach 95%), the amount of Zn added in Example 1 of this application is 1 mg and the amount of Mn added is 150 mg, while in Comparative Example 4 without Zn, the amount of Mn required to be added is 320 mg. It is evident that Zn modification can significantly reduce the amount of Mn added, thereby reducing the production cost of the catalyst.

[0102] Experiment Example 3 To further evaluate the lifespan of the catalyst prepared in Example 1, the continuous operating time was extended. The COD removal rate as a function of operating time during the first 300 days is shown in the figure below. Figure 2 As shown.

[0103] Depend on Figure 2It can be seen that the COD removal rate gradually decreases over time during 300 days of continuous operation. Using linear fitting, the fitting equation can be obtained as: ρ=97.60736-0.07508t (1-5). When t=0, ρ0=97.60736%; when t=297 days, ρ t =75.3086%.

[0104] The deactivation rate (the percentage decrease in COD removal rate per unit time) is used to estimate the catalyst's lifetime. The formula for calculating the deactivation rate is as follows: (1-6); in, —Inactivation rate, % / day; 0 — Initial COD removal rate, % t -time t COD removal rate at that time, % t —Time, days.

[0105] For t=0, ρ0=97.60736%; for t=297 days, ρ t Substituting the data of 75.3086% into formula (1-6), we get r = 0.0769% / day. It can be seen that during continuous operation, the daily percentage decrease (deactivation rate) of the catalyst is extremely small, only 0.0776%, indicating that the catalyst has good stability.

[0106] Since the catalyst is completely deactivated, only the oxidant sodium persulfate itself has an oxidizing effect. Based on experience with persulfate oxidation, it is assumed that the COD removal rate through oxidation alone is over 30%, i.e. ρ ≥30%, calculated according to the fitted equation (1), then t ≥900 days (approximately 2.5 years), meaning the catalyst's lifespan is at least 2.5 years, which further demonstrates its superior stability.

[0107] In summary, the method for preparing the MnZn@F modified persulfate catalyst provided by this invention involves fluorinating sodium silicate powder with sodium fluoride under the action of a crosslinking agent and a template agent, followed by loading Mn... 2+ and Zn 2+Granulation yielded MnZn@F modified persulfate catalyst. In this invention, sodium silicate molecular sieve is used as the support. Sodium silicate molecular sieve has extremely high specific surface area and good thermal stability (1000℃). By fluorinating the sodium silicate molecular sieve, some oxygen atoms (O) surrounding Si atoms are replaced by fluorine atoms (F), forming an F-doped molecular sieve, which increases the active sites and the stability of the material. After fluorination, Si-F bonds are formed. Because F has higher electronegativity than oxygen (O), is difficult to oxidize, and is not easily deformed, it belongs to the "hard base" category. Si, on the other hand, has a high charge density and a small ionic radius, belonging to the "hard acid" category. Therefore, the "hard base" F... - With "hard acid" Si 4+ Due to electrostatic interactions, they readily combine to form a stable complex, SiF6. 2- Compared to the original Si-O bonds, this enhances the catalyst's stability, avoids catalyst detachment issues after long-term use, and extends its service life. Subsequently, by supporting metallic Mn... 2+ and Zn 2+ Among these processes, manganese (Mn) modification provides "active sites" for reactants, offering electron transfer opportunities and promoting the reaction. It catalyzes the conversion of persulfate into sulfate radicals, which can oxidize most organic matter in water, thus improving catalytic oxidation efficiency. Meanwhile, zinc (Zn) alters the outer electronic structure and atomic structure of Mn, resulting in a more uniform catalytic reaction, better and longer-lasting catalytic performance. Simultaneously, it significantly reduces the need for Mn addition, lowering costs.

[0108] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a MnZn@F modified persulfate catalyst, characterized in that, It includes: Sodium silicate powder was fluorinated with sodium fluoride in the presence of a crosslinking agent and a template agent to obtain a fluorinated sodium silicate molecular sieve Si-F support. Mn was loaded onto the fluorine-modified sodium silicate molecular sieve Si-F support. 2+ and Zn 2+ MnZn@F modified molecular sieve catalyst was obtained; The MnZn@F modified molecular sieve catalyst was granulated to obtain a MnZn@F modified persulfate catalyst.

2. The method for preparing the MnZn@F modified persulfate catalyst according to claim 1, characterized in that, The mass ratio of the sodium silicate powder, the sodium fluoride, the crosslinking agent, and the template agent is (30-50):(0.2-0.8):(0.035-0.065):0.1-1; And / or, the crosslinking agent is trimethylolpropane or trimethylolethane; And / or, the template agent comprises at least one of hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride.

3. The method for preparing the MnZn@F modified persulfate catalyst according to claim 2, characterized in that, Fluorine modification of the sodium silicate powder includes: mixing and reacting the sodium silicate powder, the sodium fluoride and the crosslinking agent to obtain a gel; stirring the gel in a closed system to obtain crystals; and washing, first drying and calcining the crystals to obtain a fluorine-modified sodium silicate molecular sieve Si-F support.

4. The method for preparing the MnZn@F modified persulfate catalyst according to claim 3, characterized in that, Obtaining the gel involves: adding water to a mixture of the sodium silicate powder, the sodium fluoride, and the crosslinking agent to form a solution, stirring and reacting at 35-55°C for 60-120 min to form a gel solution, allowing it to stand at room temperature for 24-36 h, removing excess solvent from the surface of the gel, and obtaining the gel. And / or, the closed stirring reaction includes: stirring the gel in a closed environment at 110-180°C and 101-110 kPa for 1-6 days to obtain crystals, and then cooling to room temperature; And / or, the washing includes washing the crystals with deionized water; And / or, the temperature of the first drying is 50-70°C; And / or, the calcination includes calcination in an air atmosphere at 500-600°C for 3-6 hours.

5. The method for preparing the MnZn@F modified persulfate catalyst according to claim 1, characterized in that, The fluorine-modified sodium silicate molecular sieve Si-F support is loaded by immersing it in a mixed solution of metal salts containing manganese and zinc salts. The mass ratio of the fluorine-modified sodium silicate molecular sieve Si-F support to the mixed solution of metal salts is (2-5):3, wherein the concentration of the mixed solution of metal salts is 10%-20%, and the mass ratio of Mn:Zn in the mixed solution of metal salts is (100-160):

1. Preferably, the loading process involves first immersing the fluorine-modified sodium silicate molecular sieve Si-F support in a mixed solution of manganese and zinc salts, stirring to obtain a suspension, and then subjecting the suspension to a second drying and heat treatment to allow the Mn to react. 2+ Zn 2+ The fluorine-modified sodium silicate molecular sieve Si-F support was loaded to obtain the MnZn@F modified molecular sieve catalyst.

6. The method for preparing the MnZn@F modified persulfate catalyst according to claim 5, characterized in that, The fluorine-modified sodium silicate molecular sieve Si-F support is mixed with the metal salt mixed solution and then stirred at 30-50℃ for 4-8 hours to obtain the suspension; And / or, the second drying temperature is 100-120℃, and the drying time is 24-36h; And / or, the heat treatment temperature is 150-300℃, and the heat treatment time is 2-4h; And / or, the manganese salt includes at least one of MnCl2, MnSO4 and Mn(NO3)2; And / or, the zinc salt includes at least one of ZnCl2, ZnSO4 and Zn(NO3)2.

7. The method for preparing the MnZn@F modified persulfate catalyst according to claim 1, characterized in that, The granulation includes wet granulation or dry granulation; Preferably, the wet granulation process includes: mixing the MnZn@F modified molecular sieve catalyst and a binder, wherein the mass ratio of the catalyst to the binder is 1:(0.04-0.08); after granulation, the mixture is sieved through a 3-10 mesh screen to obtain wet particles; and the wet particles are dried at 40-60°C to obtain spherical MnZn@F modified persulfate catalyst with a particle size of 2-4 mm.

8. The method for preparing the MnZn@F modified persulfate catalyst according to claim 1, characterized in that, Before immersing the fluorine-modified sodium silicate molecular sieve Si-F support in a mixed solution of manganese and zinc salts, the process further includes soaking and acid washing the fluorine-modified sodium silicate molecular sieve Si-F support in an acidic solution with a pH of 1-3 for 2-4 hours, followed by filtration and washing with deionized water. Preferably, the acidic solution includes hydrochloric acid, sulfuric acid, or nitric acid.

9. A MnZn@F modified persulfate catalyst, characterized in that, It is prepared using the method for preparing MnZn@F modified persulfate catalyst as described in any one of claims 1-8.

10. The application of the MnZn@F modified persulfate catalyst as described in claim 9 in the preparation of persulfate catalysts for the oxidation treatment of organic wastewater.

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