Ozone catalysts, methods of making and using the same

Abstract

The application belongs to the technical field of catalyst preparation, and particularly relates to an ozone catalyst and a preparation method and application thereof. The ozone catalyst provided by the application comprises a composite metal hydroxide core and a shell layer arranged on the outer surface of the composite metal hydroxide core, wherein the shell layer comprises hydroxyl oxide. The ozone catalyst has stable structure, less metal active component dissolution, and the shell layer forms hydroxyl oxide, increases ozone catalytic active sites on the surface of the material, improves the catalytic activity of the material, and further promotes effective decomposition of ozone. The ozone catalyst can be applied in the field of wastewater treatment at low cost.

Description

Technical Field

[0001] This application belongs to the field of catalyst preparation technology, and in particular relates to an ozone catalyst, its preparation method and application. Background Technology

[0002] With the rapid development of industrialization, a large amount of complex chemical wastewater has been generated. Ozone oxidation technology has attracted widespread attention in the water treatment industry due to its advantages of simple operation, low energy consumption, and no secondary pollution. However, ozone oxidation alone is not very effective, and most ozone undergoes ineffective decomposition, resulting in resource waste. To improve the utilization rate of ozone, catalysts are generally added to promote the effective decomposition of ozone and generate hydroxyl radicals with high oxidation potential to improve the mineralization rate of pollutants. Existing relatively mature ozone catalyst preparation methods mainly include sol-gel method, impregnation-calcination method, and doping method. However, the current preparation methods are complicated to operate, and the resulting catalysts have poor stability and low activity, which is not conducive to industrial preparation.

[0003] Given the shortcomings of current ozone catalyst preparation methods, there is an urgent need to provide a new method for preparing ozone catalysts with high activity and strong stability. Summary of the Invention

[0004] The purpose of this application is to provide an ozone catalyst, its preparation method and application, aiming to solve the problems of low catalytic activity, easy dissolution of surface active components and unstable structure of ozone catalysts prepared in the prior art.

[0005] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0006] In a first aspect, this application provides an ozone catalyst, which includes a composite metal hydroxide core and a shell disposed on the outer surface of the composite metal hydroxide core, wherein the shell includes hydroxyl oxides.

[0007] Secondly, this application provides a method for preparing an ozone catalyst, comprising the following steps:

[0008] Prepare soluble salt solutions of composite metals;

[0009] A soluble salt solution of the composite metal is mixed with an alkali, and then precipitated, filtered, and dried to obtain a composite metal precipitate.

[0010] An ozone catalyst was obtained by mixing a composite metal precipitate, persulfate, and alkali and then subjecting the mixture to solid-phase ball milling.

[0011] Thirdly, this application provides an application of the above-mentioned ozone catalyst in ozone treatment of industrial wastewater, wherein the weight ratio of the ozone catalyst to the volume of the industrial wastewater is (1-3) g: 1 L.

[0012] The ozone catalyst provided in the first aspect of this application comprises a composite metal hydroxide core and a shell layer disposed on the outer surface of the composite metal hydroxide core, wherein the shell layer comprises hydroxyl oxides; therefore, the formed ozone catalyst has a stable structure, low dissolution of metal active components, and because the shell layer forms hydroxyl oxides, it increases the ozone catalytic active sites on the material surface, improves the catalytic activity of the material, and thus promotes the effective decomposition of ozone; it can be applied to the field of wastewater treatment at low cost.

[0013] The second aspect of this application provides a method for preparing an ozone catalyst. This method first provides an easily oxidizable composite metal precipitate by adding an alkaline solution. Then, the composite metal precipitate is mixed with a strong oxidant, persulfate, and subjected to thorough solid-phase oxidation under alkaline solid-phase ball milling conditions. This ensures sufficient contact between the persulfate and the composite metal precipitate, improving the utilization rate of the oxidant. The surface of the composite metal precipitate is oxidized into hydroxyl oxides with ozone catalytic effects, increasing the ozone catalytic active sites on the material surface and improving the catalytic activity of the material, thereby promoting the effective decomposition of ozone. Furthermore, it promotes the formation of a stable alloy structure between the composite metals, preventing the dissolution of active components, reducing secondary pollution, and ensuring the catalyst's cycle performance. This preparation method is simple, easy to operate, and beneficial for widespread application in industrial production.

[0014] The ozone catalyst provided in the third aspect of this application is used in the ozone treatment of industrial wastewater. Based on the stable structure and high catalytic activity of the ozone catalyst in this application, the ozone catalyst is used in the ozone treatment of industrial wastewater. The ozone catalyst can catalyze the generation of hydroxyl radicals from ozone, thereby rapidly decomposing and oxidizing pollutants in industrial wastewater, improving the utilization rate of ozone, and promoting the application of ozone in the field of industrial wastewater treatment. Detailed Implementation

[0015] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0016] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0017] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0018] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0019] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0020] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as μg, mg, g, or kg.

[0021] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0022] The first aspect of this application provides an ozone catalyst, which includes a composite metal hydroxide core and a shell disposed on the outer surface of the composite metal hydroxide core, wherein the shell includes hydroxyl oxides.

[0023] The ozone catalyst provided in the first aspect of this application comprises a composite metal hydroxide core and a shell layer disposed on the outer surface of the composite metal hydroxide core, wherein the shell layer comprises hydroxyl oxides; therefore, the formed ozone catalyst has a stable structure, low dissolution of metal active components, and because the shell layer forms hydroxyl oxides, it increases the ozone catalytic active sites on the material surface, improves the catalytic activity of the material, and thus promotes the effective decomposition of ozone; it can be applied to the field of wastewater treatment at low cost.

[0024] In some embodiments, the composite metal hydroxide core comprises a hydroxide of a first metal and a hydroxide of a second metal, wherein the first metal comprises a trivalent active metal and the second metal comprises a divalent active metal. The trivalent and divalent active metals can form a layered bimetallic hydroxide structure, which enables the generation of electron-hole pairs after the collapse of the layer-transfer structure, ensuring that the hydroxyl oxides in the shell are more likely to have more active sites, resulting in better catalytic performance.

[0025] In some embodiments, the trivalent active metal includes at least one of trivalent iron and aluminum.

[0026] In some embodiments, the divalent active metal includes at least one of nickel, copper, cobalt, and manganese.

[0027] In some embodiments, the molar ratio of the first metal and the second metal is (1-3):1. By controlling the molar amount of the first metal, which includes a trivalent active metal, to be greater, it is ensured that the composite metal hydroxide obtained from the first metal and the second metal carries a positive charge and that the interlayer is filled with exchangeable anions, which in turn promotes electron transfer and achieves a better catalytic effect.

[0028] In some specific embodiments, the molar ratio of the first metal and the second metal includes, but is not limited to, 1:1, 1.5:1, 2:1, 2.5:1, and 3:1.

[0029] The second aspect of this application provides a method for preparing an ozone catalyst, comprising the following steps:

[0030] S01. Prepare a soluble salt solution of a composite metal;

[0031] S02. Mix the soluble salt solution of the composite metal with an alkali, then precipitate, filter, and dry to obtain the composite metal precipitate;

[0032] S03. The composite metal precipitate, persulfate and alkali are mixed and then subjected to solid-phase ball milling to obtain the ozone catalyst.

[0033] The second aspect of this application provides a method for preparing an ozone catalyst. This method first provides an easily oxidizable composite metal precipitate by adding an alkaline solution. Then, the composite metal precipitate is mixed with a strong oxidant, persulfate, and subjected to thorough solid-phase oxidation under alkaline solid-phase ball milling conditions. This ensures sufficient contact between the persulfate and the composite metal precipitate, improving the utilization rate of the oxidant. The surface of the composite metal precipitate is oxidized into hydroxyl oxides with ozone catalytic effects, increasing the ozone catalytic active sites on the material surface and improving the catalytic activity of the material, thereby promoting the effective decomposition of ozone. Furthermore, it promotes the formation of a stable alloy structure between the composite metals, preventing the dissolution of active components, reducing secondary pollution, and ensuring the catalyst's cycle performance. This preparation method is simple, easy to operate, and beneficial for widespread application in industrial production.

[0034] In step S01, a composite metal soluble salt solution is prepared.

[0035] In some embodiments, the composite metal includes a first metal and a second metal, wherein the first metal includes at least one of trivalent iron and aluminum, and the second metal includes at least one of nickel, copper, cobalt, and manganese.

[0036] It can be seen that the provided composite metal soluble salt solution is a bimetallic soluble salt solution formed by the combination of trivalent and divalent active metal salts. By providing a combination of trivalent and divalent active metal salts, it is beneficial for the composite precipitate formed after subsequent precipitation with alkali to exhibit a layered structure, forming a layered bimetallic hydroxide. This facilitates the generation of electron-hole pairs after the collapse of the layer-transfer structure, ensuring that the oxide obtained after oxidation treatment is more likely to have more active sites and thus has a better catalytic effect.

[0037] In some embodiments, the molar ratio of the first metal and the second metal is (1-3):1. By controlling the molar amount of the first metal, which includes a trivalent active metal, to be greater, it is ensured that the composite metal hydroxide obtained from the first metal and the second metal carries a positive charge and that the interlayer is filled with exchangeable anions, which in turn promotes electron transfer and achieves a better catalytic effect.

[0038] In some specific embodiments, the molar ratio of the first metal and the second metal includes, but is not limited to, 1:1, 1.5:1, 2:1, 2.5:1, and 3:1.

[0039] In some embodiments, the soluble salt solution includes at least one of a soluble sulfate solution, a soluble nitrate solution, and a soluble chloride solution.

[0040] In some specific embodiments, ferric salts include, but are not limited to, at least one of ferric sulfate, ferric nitrate, and ferric chloride; aluminum salts include, but are not limited to, at least one of aluminum sulfate, aluminum nitrate, and aluminum chloride.

[0041] In some embodiments, the divalent active metal salt includes at least one of nickel salt, copper salt, cobalt salt, and manganese salt. In some specific embodiments, the nickel salt includes, but is not limited to, at least one of nickel sulfate, nickel nitrate, and nickel chloride; the copper salt includes, but is not limited to, at least one of copper sulfate, copper nitrate, and copper chloride; the cobalt salt includes, but is not limited to, at least one of cobalt sulfate, cobalt nitrate, and cobalt chloride; and the manganese salt includes, but is not limited to, at least one of manganese sulfate, manganese nitrate, and manganese chloride.

[0042] In some embodiments, the step of preparing a composite metal soluble salt solution includes: providing a first metal salt and a second metal salt in a certain molar ratio, mixing them with a certain amount of pure water, and stirring at room temperature and 400-500 rpm for 3-4 hours to obtain a composite metal soluble salt solution.

[0043] Step S02. Mix the soluble salt solution of the composite metal with an alkali, then precipitate, filter, and dry to obtain the composite metal precipitate.

[0044] In some embodiments, during the step of mixing the composite metal soluble salt solution and the alkali, the pH of the resulting solution is controlled to be 11–13. By mixing the alkali solution and the composite metal soluble salt solution, an easily oxidizable composite metal hydroxide is prepared.

[0045] In some embodiments, the alkali includes, but is not limited to, at least one of sodium hydroxide and potassium hydroxide.

[0046] In some specific embodiments, the alkali is selected from sodium hydroxide solution with a concentration of 0.1 to 0.5 mol / L.

[0047] In some embodiments, the drying temperature is 60–80°C, and the drying time is 12–14 hours. The main purpose is to dry the composite metal precipitate, and the specific drying temperature is determined according to the drying time.

[0048] In some specific embodiments, the steps for obtaining the composite metal precipitate include: mixing a soluble salt solution of the composite metal with a 0.1 mol / L sodium hydroxide solution, adjusting the pH of the mixed solution to 11-13; stirring for 1 hour and filtering to obtain the composite metal precipitate; rinsing the composite metal precipitate with water; and drying it at 60-80°C for 12-14 hours to obtain the composite metal precipitate.

[0049] In step S03, the composite metal precipitate, persulfate, and alkali are mixed and then subjected to solid-phase ball milling to obtain the ozone catalyst. The composite metal precipitate and the strong oxidant persulfate are mixed and subjected to thorough solid-phase oxidation under alkaline solid-phase ball milling conditions. This ensures sufficient contact between the persulfate and the composite metal precipitate, improves the utilization rate of the oxidant, and oxidizes the surface of the composite metal precipitate into hydroxyl oxides with ozone catalytic effects. This increases the ozone catalytic active sites on the material surface, improves the catalytic activity of the material, and thus promotes the effective decomposition of ozone. Furthermore, it promotes the formation of a stable alloy structure between the composite metals, prevents the dissolution of active components, reduces secondary pollution, and ensures the catalyst's cycle performance. This preparation method is simple, easy to operate, and conducive to widespread application in industrial production.

[0050] In some embodiments, the persulfate includes at least one of ammonium persulfate, sodium persulfate, and potassium persulfate. Providing a strong oxidizing agent, the persulfate, can oxidize the surface of the composite metal precipitate into hydroxyl oxides with ozone-catalyzing effects, increasing the ozone-catalyzing active sites on the material surface, improving the catalytic activity of the material, and thus promoting the effective decomposition of ozone.

[0051] Furthermore, the reactants provided, in addition to the composite metal precipitate and persulfate, also include an alkali. During the solid-phase ball milling process, the alkali is provided for mixing. This serves two purposes: firstly, it has a water-absorbing effect, providing some wetting to the composite metal precipitate and persulfate, thus improving the contact effect; secondly, it avoids introducing impurities, ensuring a high purity of the resulting catalyst.

[0052] In some embodiments, the molar ratio of the composite metal precipitate, persulfate, and alkali is 1:(1-4):(2-4). Providing an excess of persulfate and alkali to react with the composite metal precipitate helps ensure sufficient solid-phase oxidation of the composite material surface, generating hydroxyl oxides with ozone catalytic effects and forming a stable alloy structure. In some specific embodiments, the molar ratio of the composite metal precipitate, persulfate, and alkali includes, but is not limited to, 1:1:2, 1:2:2, 1:2.5:2.5, 1:3:3, 1:3.5:3.5, and 1:4:4.

[0053] In some embodiments, during the solid-phase ball milling process, the milling speed is 100–200 rpm and the time is 2–4 hours. Under these conditions, the efficiency of the solid-phase ball milling process can be significantly improved, ensuring uniform milling and sufficient solid-phase oxidation of the composite material surface. This results in the formation of hydroxyl oxides with ozone catalytic effects and the formation of a stable alloy structure.

[0054] In some specific embodiments, the ball milling speed includes, but is not limited to, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, 160 rpm, 170 rpm, 180 rpm, 190 rpm, and 200 rpm.

[0055] In some specific embodiments, the ball milling time includes, but is not limited to, 2 hours, 2.5 hours, 3 hours, 3.5 hours, and 4 hours.

[0056] In some embodiments, during the solid-phase ball milling process, the ball-to-material ratio is (3-4):1; and the diameter of the grinding balls is 10-12 mm. Controlling the ball-to-material ratio and the diameter of the grinding balls ensures that the abrasive is fully ground, while avoiding excessive ball material that could affect grinding efficiency.

[0057] In some specific embodiments, the ball-to-material ratio includes, but is not limited to, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, and 4:1.

[0058] In some specific embodiments, the diameter of the grinding ball includes, but is not limited to, 10mm, 10.2mm, 10.4mm, 10.6mm, 10.8mm, 11mm, 11.2mm, 11.4mm, 11.6mm, 11.8mm, and 12mm.

[0059] The second aspect of this application provides an ozone catalyst, which is prepared by the ozone catalyst preparation method described above.

[0060] The ozone catalyst provided in the second aspect of this application is prepared by a solid-phase ball milling method. The surface of the ozone catalyst is composed of hydroxyl oxides and the interior is composed of composite metal hydroxides. The structure is relatively stable and the metal active components are leached out in small amounts. It has high catalytic activity during use and can be applied to the field of wastewater treatment at low cost.

[0061] The third aspect of this application provides the application of an ozone catalyst in ozone treatment of industrial wastewater, wherein the weight ratio of the ozone catalyst to the volume of the industrial wastewater is (1-3) g: 1 L.

[0062] The ozone catalyst provided in the third aspect of this application is used in the ozone treatment of industrial wastewater. Based on the stable structure and high catalytic activity of the ozone catalyst in this application, the ozone catalyst is used in the ozone treatment of industrial wastewater. The ozone catalyst can catalyze the generation of hydroxyl radicals from ozone, thereby rapidly decomposing and oxidizing pollutants in industrial wastewater, improving the utilization rate of ozone, and promoting the application of ozone in the field of industrial wastewater treatment.

[0063] In some embodiments, the weight ratio of ozone catalyst to the volume of industrial wastewater is (1-3) g:1L, which means that 1g, 1.5g, 2g, 2.5g, or 3g of the ozone catalyst of this application can be used in 1L of industrial wastewater.

[0064] The following description is based on specific embodiments.

[0065] Example 1

[0066] Weigh 27.8g of ferric sulfate (Fe2(SO4)3) and 13.14g of nickel sulfate hexahydrate (NiSO4·6H2O) (Fe2(SO4)3). 3+ :Ni 2+ Add 500 ml of pure water to a beaker (molar ratio of 2:1), and stir at room temperature and 500 rpm for 3 hours to fully dissolve the materials and obtain a clear mixed solution.

[0067] Reduce the rotation speed to 400 rpm, add 0.1 mol / L sodium hydroxide solution dropwise to adjust the pH of the mixed solution to 12. After the pH of the system stabilizes, continue stirring for 1 hour to ensure sufficient precipitate formation. Stop stirring, then filter, rinse with an appropriate amount of pure water, and transfer to an oven to dry at 60°C for 12 hours.

[0068] The dried filter residue, 68.46g of ammonium persulfate, and 8g of sodium hydroxide were added to a ball mill in a molar ratio of 1:2:2 and ball-milled at 150 rpm for 2 hours to ensure thorough mixing of the materials. The ball-milled powder was rinsed with an appropriate amount of distilled water to remove the ammonium persulfate, sodium hydroxide, and other auxiliary materials. The powder was then dried at 60°C for 12 hours and ground to obtain the ozone catalyst.

[0069] Weigh 5g of the prepared material into a 1L volume air flotation column, add 500mL of industrial wastewater (industrial wastewater indicators are shown in Table 1), and use an ozone generator to introduce ozone from the bottom of the air flotation column at a flow rate of 8ml / min for 2 hours. After aeration is stopped, filter the solution and take the filtrate for analysis. The COD in the filtrate is reduced to 54.3mg / L, and the COD removal rate is 92.16%.

[0070] Example 2

[0071] Weigh 41.7g of ferric sulfate (Fe2(SO4)3) and 13.14g of nickel sulfate hexahydrate (NiSO4·6H2O) (Fe2(SO4)3). 3+ :Ni 2+ Add 500 ml of pure water to a beaker (molar ratio of 3:1), and stir at room temperature and 500 rpm for 3 hours to fully dissolve the materials and obtain a clear mixed solution.

[0072] Reduce the rotation speed to 400 rpm, add 0.1 mol / L sodium hydroxide solution dropwise to adjust the pH of the mixed solution to 12, and continue stirring for 1 hour after the pH of the system stabilizes to ensure sufficient precipitation. Stop stirring, filter, rinse with an appropriate amount of pure water, and then transfer to an oven to dry at 60°C for 12 hours.

[0073] The dried filter residue, 34.23g of ammonium persulfate, and 8g of sodium hydroxide were added to a ball mill in a molar ratio of 1:1:2 and ball-milled at 150 rpm for 2 hours to ensure thorough mixing of the materials. The ball-milled powder was rinsed with an appropriate amount of distilled water to remove the ammonium persulfate, sodium hydroxide, and other auxiliary materials. The powder was then dried at 80°C for 12 hours and ground to obtain the ozone catalyst.

[0074] Weigh 5g of the prepared material into a 1L volume air flotation column, add 500mL of industrial wastewater, and use an ozone generator to introduce ozone from the bottom of the air flotation column at a flow rate of 8ml / min for 2 hours. After aeration is stopped, filter the solution and take the filtrate for analysis. The COD in the filtrate is reduced to 79.6mg / L, and the COD removal rate is 88.51%.

[0075] Example 3

[0076] Weigh 27.8g of ferric sulfate (Fe2(SO4)3) and 13.14g of nickel sulfate hexahydrate (NiSO4·6H2O) (Fe2(SO4)3). 3+ :Ni 2+ Add 500 ml of pure water to a beaker (molar ratio of 2:1), and stir at room temperature and 500 rpm for 3 hours to fully dissolve the materials and obtain a clear mixed solution.

[0077] Reduce the rotation speed to 400 rpm, add 0.1 mol / L sodium hydroxide solution dropwise to adjust the pH of the mixed solution to 12, and continue stirring for 1 hour after the pH of the system stabilizes to ensure sufficient precipitation. Stop stirring, filter, rinse with an appropriate amount of pure water, and then transfer to an oven to dry at 60°C for 12 hours.

[0078] The dried filter residue, 34.23g of ammonium persulfate, and 8g of sodium hydroxide were added to a ball mill in a molar ratio of 1:1:2 and ball-milled at 150 rpm for 2 hours to ensure thorough mixing of the materials. The ball-milled powder was rinsed with an appropriate amount of distilled water to remove the ammonium persulfate, sodium hydroxide, and other auxiliary materials. The powder was then dried at 80°C for 12 hours and ground to obtain the ozone catalyst.

[0079] Weigh 5g of material into a 1L volume air flotation column, add 500mL of industrial wastewater, and use an ozone generator to introduce ozone from the bottom of the air flotation column at a flow rate of 8ml / min for 2 hours. After aeration is stopped, filter the solution and take the filtrate for analysis. The COD in the filtrate is reduced to 98.6mg / L, and the COD removal rate is 85.77%.

[0080] Comparative Example 1

[0081] Weigh 27.8g of ferric sulfate (Fe2(SO4)3) and 13.14g of nickel sulfate hexahydrate (NiSO4·6H2O) (Fe2(SO4)3). 3+ :Ni 2+ Add 500 ml of pure water to a beaker (molar ratio of 2:1), and stir at room temperature and 500 rpm for 3 hours to fully dissolve the materials and obtain a clear mixed solution.

[0082] Reduce the rotation speed to 400 rpm, add 0.1 mol / L sodium hydroxide solution dropwise to adjust the pH of the mixed solution to 12, and continue stirring for 1 hour after the pH of the system stabilizes to ensure sufficient precipitation. Stop stirring, filter, rinse with an appropriate amount of pure water, transfer to an oven and dry at 60°C for 12 hours, and grind to obtain the iron-nickel composite material.

[0083] Weigh 5g of material into a 1L volume air flotation column, add 500mL of industrial wastewater, and use an ozone generator to introduce ozone from the bottom of the air flotation column at a flow rate of 8ml / min for 2 hours. After aeration is stopped, filter the solution and take the filtrate for analysis. The COD in the filtrate is reduced to 429.6mg / L, and the COD removal rate is 38%.

[0084] Comparative Example 2

[0085] 500 mL of industrial wastewater was added to a 1 L volume air flotation column. Ozone was introduced from the bottom of the air flotation column using an ozone generator at a flow rate of 8 ml / min for 2 hours. After aeration was stopped, the column was filtered and the filtrate was analyzed. The COD in the filtrate was reduced to 564.3 mg / L, and the COD removal rate was 18.55%.

[0086] Comparative Example 3

[0087] Weigh 27.8g of ferric sulfate (Fe2(SO4)3) and 13.14g of nickel sulfate hexahydrate (NiSO4·6H2O) (Fe2(SO4)3). 3+ :Ni 2+ Add 500 ml of pure water to a beaker (molar ratio of 2:1), and stir at room temperature and 500 rpm for 3 hours to fully dissolve the materials and obtain a clear mixed solution.

[0088] Reduce the rotation speed to 400 rpm, add 0.1 mol / L sodium hydroxide solution dropwise to adjust the pH of the mixed solution to 12. After the pH of the system stabilizes, continue stirring for 1 hour to ensure sufficient precipitate formation. Stop stirring, then filter, rinse with an appropriate amount of pure water, and transfer to an oven to dry at 60°C for 12 hours.

[0089] The dried filter residue, 68.46g of ammonium persulfate, and 8g of sodium hydroxide were added to a ball mill in a molar ratio of 1:2:2 and ball-milled at 150 rpm for 2 hours to ensure thorough mixing of the materials. The ball-milled powder was rinsed with an appropriate amount of distilled water to remove the ammonium persulfate, sodium hydroxide, and other auxiliary materials. The powder was then dried at 80°C for 12 hours and ground to obtain the ozone catalyst.

[0090] During use, only ozone catalyst and industrial wastewater were mixed to investigate the adsorption effect of ozone catalyst on COD.

[0091] Weigh 5g of material into a 1L beaker, add 500mL of industrial wastewater, and stir at 500rpm for 2h at room temperature. After stirring, filter and take the filtrate for analysis. The COD in the filtrate decreased to 678.6mg / L, and the COD removal rate was 2.05%.

[0092] Comparative Example 4

[0093] Weigh 27.8g of ferric sulfate (Fe2(SO4)3) and 13.14g of nickel sulfate hexahydrate (NiSO4·6H2O) (Fe2(SO4)3). 3+ :Ni 2+ Add 500 ml of pure water to a beaker (molar ratio of 2:1), and stir at room temperature and 500 rpm for 3 hours to fully dissolve the materials and obtain a clear mixed solution.

[0094] Reduce the rotation speed to 400 rpm, add 0.1 mol / L sodium hydroxide solution dropwise to adjust the pH of the mixed solution to 12, and continue stirring for 1 hour after the pH of the system stabilizes to ensure sufficient precipitation. Stop stirring, filter, rinse with an appropriate amount of pure water, and then transfer to an oven to dry at 60°C for 12 hours.

[0095] The dried filter residue, 171.15g of ammonium persulfate, and 20g of sodium hydroxide were added to a ball mill in a molar ratio of 1:5:5 and ball-milled at 150 rpm for 2 hours to ensure thorough mixing of the materials. The ball-milled powder was rinsed with an appropriate amount of distilled water to remove the ammonium persulfate, sodium hydroxide, and other auxiliary materials. The powder was then dried at 80°C for 12 hours and ground to obtain the ozone catalyst.

[0096] Weigh 5g of material into a 1L volume air flotation column, add 500mL of industrial wastewater, and use an ozone generator to introduce ozone from the bottom of the air flotation column at a flow rate of 8ml / min for 2 hours. After aeration is stopped, filter the solution and take the filtrate for analysis. The COD in the filtrate is reduced to 316.2mg / L, and the COD removal rate is 54.36%.

[0097] Comparative Example 5

[0098] Weigh 55.6g of ferric sulfate (Fe2(SO4)3) and 13.14g of nickel sulfate hexahydrate (NiSO4·6H2O) (Fe2(SO4)3). 3+ :Ni 2+ Add 500 ml of pure water to a beaker (molar ratio 4:1), and stir at room temperature and 500 rpm for 3 hours to fully dissolve the materials and obtain a clear mixed solution. Reduce the speed to 400 rpm, and add 0.1 mol / L sodium hydroxide solution dropwise to adjust the pH of the mixed solution to 12. After the pH value of the system stabilizes, continue stirring for 1 hour to ensure sufficient precipitation. Stop stirring, filter, rinse with an appropriate amount of pure water, and transfer to an oven to dry at 60℃ for 12 hours. Add the dried filter residue, 68.46 g of ammonium persulfate, and 8 g of sodium hydroxide to a ball mill at a molar ratio of 1:2:2, and ball mill at 150 rpm for 2 hours to ensure thorough mixing of the materials. Rinse the ball-milled powder with an appropriate amount of distilled water to remove the ammonium persulfate, sodium hydroxide, and other auxiliary materials. Dry at 80℃ for 12 hours, and grind to obtain the ozone catalyst.

[0099] Weigh 5g of material into a 1L volume air flotation column, add 500mL of industrial wastewater, and use an ozone generator to introduce ozone from the bottom of the air flotation column at a flow rate of 8ml / min for 2 hours. After aeration is stopped, filter the solution and take the filtrate for analysis. The COD in the filtrate is reduced to 289.5mg / L, and the COD removal rate is 58.21%.

[0100] The indicators of the industrial wastewater treated by Examples 1-3 and Comparative Examples 1-3 are shown in Table 1.

[0101] Table 1

[0102] Samples to be processed COD (mg / L) Oil (mg / L) pH Industrial wastewater 692.8 12 7.56

[0103] Performance testing

[0104] The application effect data of the preparations obtained in Examples 1-3 and Comparative Examples 1-5 are shown in Table 2 below.

[0105] Table 2

[0106] COD value (mg / L) in the treated sample COD removal rate (%) Example 1 54.3 92.16 Example 2 79.6 88.51 Example 3 98.6 85.77 Comparative Example 1 429.6 38 Comparative Example 2 564.3 18.55 Comparative Example 3 678.6 2.05 Comparative Example 4 316.2 54.36 Comparative Example 5 289.5 58.21

[0107] According to Table 2 above, under the conditions of room temperature and ozone flux of 8 mg / L, the COD removal efficiency of the ozone oxidants obtained in Examples 1-3 in industrial wastewater was 92.16%, 88.51%, and 85.77%, respectively. Compared with Comparative Examples 1-3, it can be seen that the catalytic effect of the ozone oxidant provided in this application is significantly improved, proving that the ozone catalyst prepared by solid-phase ball milling with ammonium sulfate has better ozone catalytic ability. XRD detection showed that the ozone catalysts prepared by solid-phase ball milling in Examples 1-3 and Comparative Examples 3-4 had hydroxyl oxides on their surface, and the amount of hydroxyl oxides on the surface of the ozone catalyst in Comparative Example 4 was less than that in Examples 1-3 and Comparative Example 2. No hydroxyl oxides were detected on the surface of the ozone catalysts prepared in Comparative Examples 1-2. Compared with Comparative Example 4, the proportion of ball milling raw materials needs to be controlled within a reasonable range. Too much oxidant will cause the material to be over-oxidized to form metal oxides, thus failing to generate catalytically active hydroxyl oxides, thereby reducing the catalytic effect of ozone. Comparing Examples 1, 2, 3, and 5, the molar ratio of the first metal to the second metal in Examples 1-3 was (2-3):1, while the molar ratio of the first metal to the second metal in Comparative Example 5 was 4:1. The resulting products were processed. The COD values ​​of the samples treated in Examples 1-3 were below 100 mg / L, with removal rates of 85.77%-92.16%. The COD value of the sample treated in Comparative Example 5 was 289.5 mg / L, with a removal rate of 58.21%. Therefore, it can be seen that a specific molar ratio of the first metal to the second metal is required to achieve a catalytic effect in reducing ozone.

[0108] Furthermore, analysis of the filtrate after 2 hours of ozone aeration in Example 1 revealed that the Ni and Fe contents were only approximately 2 ppm and 4 ppm, respectively, indicating that the prepared ozone catalyst material possesses a stable structure and reduces the loss of active components. Moreover, after drying the ozone catalyst at 60°C and reusing it, the effects after five cycles were 92.16%, 90.88%, 89.12%, 86.41%, and 82.1%, respectively, with the COD removal rate remaining above 80%, demonstrating the catalyst's excellent recyclability.

[0109] In summary, the ozone catalyst provided in this application has a stable structure, low dissolution of metal active components, and the formation of hydroxyl oxides in the shell increases the ozone catalytic active sites on the material surface, thereby improving the catalytic activity of the material and promoting the effective decomposition of ozone; it can be applied to the field of wastewater treatment at low cost.

[0110] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An ozone catalyst characterized in that, The ozone catalyst comprises a composite metal hydroxide inner core and a shell layer arranged on the outer surface of the composite metal hydroxide inner core, wherein the shell layer comprises hydroxyl oxide; the composite metal hydroxide inner core comprises hydroxide of a first metal and hydroxide of a second metal, wherein the first metal comprises at least one of trivalent iron and aluminum, and the second metal comprises at least one of divalent nickel, copper, cobalt and manganese; and the preparation method of the ozone catalyst comprises the following steps: a step of preparing a composite metal soluble salt solution; a step of mixing the composite metal soluble salt solution and an alkali, and then performing precipitation, filtration and drying to obtain a composite metal precipitate; a step of mixing the composite metal precipitate, a persulfate and an alkali, and then performing solid-phase ball milling treatment to obtain the ozone catalyst.

2. The ozone catalyst according to claim 1, characterized in that, The molar ratio of the first metal to the second metal is (1-3):

1.

3. The ozone catalyst of claim 1, wherein The soluble salt solution comprises at least one of a soluble sulfate solution, a soluble nitrate solution and a soluble chloride solution; and the persulfate comprises at least one of ammonium persulfate, sodium persulfate and potassium persulfate.

4. The ozone catalyst of claim 1, wherein In the step of solid-phase ball milling treatment, the molar ratio of the composite metal precipitate, the persulfate and the alkali is 1:(1-4):(2-4).

5. The ozone catalyst of claim 1, wherein In the step of mixing the composite metal soluble salt solution and the alkali, the pH of the mixed solution is controlled to be 11-13.

6. The ozone catalyst of claim 1, wherein In the step of solid-phase ball milling treatment, the rotation speed of the ball milling treatment is 100-200 rpm, and the time is 2-4 hours.

7. Use of the ozone catalyst according to any one of claims 1 to 6 for the treatment of industrial waste water with ozone, wherein The ratio of the weight of the ozone catalyst to the volume of the industrial wastewater is (1-3) g: 1 L.