Supported ozone catalyst, preparation method thereof, spherical ozone catalyst and application of spherical ozone catalyst

Abstract

The invention discloses a supported ozone catalyst, a preparation method thereof, a spherical ozone catalyst and application thereof, and belongs to the technical field of water treatment and environmental catalysis. The supported ozone catalyst comprises an active component, an auxiliary carbon component and a carrier, the carrier is modified gamma-Al2O3 (aluminum oxide) or modified SiO2 (silicon dioxide); the active component and the additive carbon component are dispersed on the outer surface of the carrier and the inner surface of a pore channel; the active component is an iron-cobalt composite oxide and has a spinel crystal form; the additive carbon component is prepared by calcining urea and citric acid in an inert atmosphere. The active components in the supported ozone catalyst are highly dispersed, the activation efficiency of ozone can be remarkably improved by the supported ozone catalyst under the assistance of the carbon component, and high-efficiency removal of refractory organic pollutants in wastewater is realized.

Description

Technical Field

[0001] This invention relates to the field of water treatment and environmental catalysis technology, and in particular to a supported ozone catalyst and its preparation method, a spherical ozone catalyst and its application. Background Technology

[0002] Ozone oxidation technology, due to its oxidizing properties, is widely used in the treatment of recalcitrant organic pollutants. However, using ozone alone suffers from low mass transfer efficiency, rapid decomposition rate, and insufficient oxidation capacity, limiting its practical application efficiency. To improve ozone utilization, researchers have developed ozone catalytic oxidation technology. The addition of a catalyst significantly enhances the oxidation capacity of the ozone system. Ozone catalysts efficiently activate ozone to generate highly oxidizing hydroxyl radicals, greatly improving the treatment efficiency of recalcitrant pollutants. This technology has been widely used in water treatment and waste gas purification, but its large-scale promotion remains limited by factors such as cost, stability, selectivity, and adaptability to complex operating conditions.

[0003] Currently, supported metal oxide ozone catalysts have attracted widespread attention due to their high stability and reusability. However, traditional loading methods often suffer from problems such as low efficiency of the metal active component, poor dispersibility, easy agglomeration, and complex preparation processes. Therefore, there is an urgent need for a simple, controllable method that can achieve highly dispersed active component loading to improve the overall performance and engineering application value of ozone catalysts. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a supported ozone catalyst and its preparation method, a spherical ozone catalyst and its application. The supported ozone catalyst can significantly enhance ozone utilization efficiency and increase the degradation rate of organic pollutants in wastewater.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a supported ozone catalyst, which includes an active component, a carbon component as an auxiliary agent, and a support;

[0007] The support is modified γ-Al2O3 or modified SiO2;

[0008] The active component and the auxiliary carbon component are dispersed on the outer surface and the inner surface of the pores of the carrier;

[0009] The active component is an iron-cobalt composite oxide, which has a spinel crystal form;

[0010] The carbon component of the additive is prepared by calcining urea and citric acid under an inert atmosphere.

[0011] Preferably, the calcination temperature is 580℃-620℃. The carbon component has a good porous structure, which helps the active component to be highly dispersed on the outer surface and inner surface of the pores of the modified γ-Al2O3 support or modified SiO2 support. When the supported ozone catalyst is applied to the ozone degradation of pollutants, the auxiliary carbon component in the supported catalyst can better adsorb pollutants, improve the contact rate between the supported catalyst and the pollutants being treated, increase the contact area, better exert its catalytic activity, and achieve rapid and efficient degradation of the pollutants being treated.

[0012] Preferably, the carrier is obtained by sequentially treating γ-Al2O3 or SiO2 powder with sodium hydroxide solution and a modifier.

[0013] Preferably, the modifier is selected from silane coupling agents, organic amine compounds, or polyol compounds.

[0014] The concentration of the sodium hydroxide solution is preferably 0.01-0.5 mol·L⁻¹. -1 .

[0015] When using sodium hydroxide solution for treatment, the preferred solid-liquid ratio is controlled at 5-50 mL·g. -1 The processing temperature is 40℃-80℃.

[0016] The concentration of the modifier is preferably 0.1wt%-5wt%.

[0017] The silane coupling agents include, but are not limited to, 3-aminopropyltriethoxysilane, n-octyltriethoxysilane, tetraethoxysilane, etc.

[0018] The organic amine compounds include, but are not limited to, ethylenediamine (EDA), triethylamine (TEA), triethanolamine (TEOA), tetrapropylammonium hydroxide, etc.

[0019] The polyol compounds include, but are not limited to, ethylene glycol, propylene glycol, glycerol, pentaerythritol, etc.

[0020] After treatment with the sodium hydroxide solution and modifier, the process includes subsequent treatments such as filtration, washing, and drying.

[0021] The drying temperature is preferably 80℃-120℃.

[0022] This invention also provides a method for preparing the above-mentioned ozone catalyst, comprising the following steps:

[0023] (1) Mix soluble iron salt, soluble cobalt salt, ethanol, citric acid, acetone and water to react and obtain metal complex system S1;

[0024] (2) Mix S1 with soluble metal salt, structure modifier and urea to obtain system S2;

[0025] (3) Mix and impregnate modified γ-Al2O3 or modified SiO2 with system S2 to obtain system S3;

[0026] (4) After filtering and drying the system S3 in sequence, it is calcined under an inert atmosphere to prepare the supported ozone catalyst.

[0027] Preferably, the calcination temperature is 580℃-620℃; more preferably 590℃-600℃; and even more preferably 600℃.

[0028] The preferred heating rate for the calcination temperature is 5~10 °C / min. In the above preparation method, step (1) mixes to obtain a transparent or homogeneous solution. The carboxyl group in the citric acid and the hydroxyl group in the ethanol molecule can form a stable chelate with the metal ions, so that the metal component remains highly dispersed during the subsequent loading process.

[0029] A portion of the citric acid is used to form the aforementioned chelate, and the remaining portion, together with the urea, forms the auxiliary carbon component under the inert atmosphere during calcination.

[0030] The inert atmosphere includes, but is not limited to, argon, nitrogen, etc.

[0031] In addition, the urea can also be used as a slow-release deposition regulator to regulate the deposition of complexes in the metal-metal complex system S1.

[0032] The preferred mass ratio of urea to soluble iron salt is (0.01-0.3):0.05; more preferably (0.05-0.2):0.05; and even more preferably 0.1:0.05. The preparation method of this invention has certain limitations on the molar amounts of iron and cobalt; otherwise, it is difficult to prepare a supported ozone catalyst with excellent performance.

[0033] Preferably, the molar amount of iron in the soluble iron salt is ≥0.31 mmol;

[0034] Preferably, the molar amount of cobalt in the soluble cobalt salt is ≥0.19 mmol;

[0035] Preferably, the ratio of ethanol to citric acid is (30-50) mL: (0.05-0.2) g; more preferably, it is 40 mL: 0.1 g.

[0036] Preferably, the soluble iron salt is selected from ferric chloride, ferric nitrate, or ferric acetate; more preferably, it is ferric chloride.

[0037] Preferably, the soluble cobalt salt is selected from cobalt chloride, cobalt nitrate, cobalt acetate, or cobalt sulfate; more preferably, it is cobalt chloride.

[0038] In the above preparation method, the purpose of adding the soluble cooperating metal salt and structure modifier in step (2) is to improve the dispersion of the iron and cobalt components and promote their better loading on the support. Ultimately, the cooperating metal in the soluble cooperating metal salt does not exist in the supported catalyst structure because the transition metal will form a metal precipitate after the addition of NaOH, and the cooperating metal Mg is an alkali metal that dissolves in water and will be lost during solid-liquid separation.

[0039] Preferably, the soluble metal salt is selected from magnesium sulfate or magnesium nitrate;

[0040] The preferred molar ratio of the auxiliary metal in the soluble auxiliary metal salt to the iron in the soluble iron salt is (0.01-0.02):0.3; more preferably, it is 0.01:0.3.

[0041] The auxiliary metal salt can be introduced by directly adding the solid or by pre-dissolving and then adding dropwise.

[0042] Preferably, the structure modifier is selected from one or more of polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and polyacrylic acid (PAA); more preferably, it is polyvinylpyrrolidone.

[0043] The molecular weight of the polyvinylpyrrolidone is preferably 30,000.

[0044] The mass ratio of the structure modifier to the soluble iron salt is (0.01-0.5):0.05; more preferably (0.1-0.3):0.05; and even more preferably 0.2:0.05.

[0045] In the above preparation method, after the impregnation in step (3), the pH value is adjusted to 7-10. The purpose is to better perform the filtration in step (4) and ensure that the transition metal is uniformly bound to the carrier in the form of precipitate.

[0046] The filtration in step (4) preferably uses a Buchner funnel equipped with a microporous filter membrane.

[0047] The pore size of the microporous filter membrane is preferably 0.22-1 μm.

[0048] The microporous filter membrane is made of polytetrafluoroethylene (PTFE) or polyethersulfone (PES) to ensure good chemical resistance and mechanical stability.

[0049] The drying temperature in step (4) is preferably 60°C-80°C.

[0050] Through the complexation reaction described above, as well as the combined effects of soluble co-metal salts and structure modifiers, the metal components in the supported catalyst are highly dispersed, resulting in a more stable overall catalyst structure.

[0051] The supported catalyst described in this invention can significantly improve the activation efficiency of ozone and enhance the generation rate of highly reactive oxygen species such as •OH, thereby achieving efficient removal of recalcitrant organic pollutants.

[0052] To reduce the loss and consumption of the supported ozone catalyst during actual use, and to reduce the equipment blockage caused by it, which would increase costs due to the need for solid-liquid separation equipment, the supported ozone catalyst can be granulated to form spherical ozone catalysts, which can then be directly applied to fixed-bed or fluidized-bed reactors used for wastewater treatment.

[0053] The present invention also provides a spherical ozone catalyst, which is prepared by mixing and granulating the above-mentioned supported ozone catalyst or the supported ozone catalyst prepared by the above-mentioned preparation method with a binder.

[0054] The supported ozone catalyst and binder were uniformly mixed without significant phase separation.

[0055] Preferably, the spherical ozone catalyst of the present invention has a particle size of 2-4 mm.

[0056] Preferably, the mass ratio of the supported ozone catalyst to the binder is (500-2000):1; more preferably, it is 1000:1.

[0057] This invention selects a suitable adhesive to ensure the strength of the spheres and the stability of the pore structure.

[0058] Preferably, the adhesive is composed of one or more of hydroxypropyl cellulose, polyvinyl alcohol, and amide; more preferably, the adhesive is composed of hydroxypropyl cellulose and polyvinyl alcohol; even more preferably, the adhesive contains 60%-70% hydroxypropyl cellulose and 30%-40% polyvinyl alcohol.

[0059] During the granulation process, the binder is added in batches to achieve dynamic distribution of the binder during granulation. In the first step, 30%-40% of the total mass of the binder is added to the supported catalyst powder to obtain primary particles. In the second step, the remaining binder is dissolved in water and then added to the primary particles to obtain the final spherical ozone catalyst.

[0060] The granulation process also includes particle sieving and drying.

[0061] The particle sieving yields spherical ozone catalysts with a particle size of 2-4 mm.

[0062] The drying temperature is preferably 100℃-110℃.

[0063] The supported ozone catalyst or the spherical ozone catalyst of the present invention can effectively promote the decomposition of ozone to generate highly active oxide species such as •OH, significantly improve the ozone oxidation efficiency, and is suitable for the deep treatment of recalcitrant organic pollutants. It exhibits excellent catalytic performance and stability in various wastewater treatment fields.

[0064] The present invention also provides the application of the above-mentioned spherical ozone catalyst in the degradation of oxalic acid or atrazine.

[0065] The use of the supported ozone catalyst or the spherical ozone catalyst described in this invention to degrade oxalic acid or atrazine in wastewater has the advantages of being simple, safe, and low-cost, making it suitable for large-scale industrial applications.

[0066] Compared with existing technologies, the supported ozone catalyst provided by this invention comprises an active component, a carbon auxiliary component, and a support; the support is modified γ-Al₂O₃ or modified SiO₂; the active component and the carbon auxiliary component are dispersed on the outer surface and inner surface of the pores of the support; the active component is an iron-cobalt composite oxide with a spinel crystal form; the carbon auxiliary component is prepared by calcining urea and citric acid under an inert atmosphere. In the supported ozone catalyst of this invention, the active component is highly dispersed, and with the assistance of the carbon component, the supported ozone catalyst can significantly improve the ozone activation efficiency, achieving efficient removal of recalcitrant organic pollutants from wastewater. Attached Figure Description

[0067] Figure 1 The images show the appearance of the catalysts synthesized in Example 1 (left) and Comparative Example 1 (right).

[0068] Figure 2 The surface electron microscope (SEM) images of catalysts S1, S2, S3, S4, S5, and S6 synthesized in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, respectively.

[0069] Figure 3 This is a transmission electron microscope (TEM) image of the catalyst synthesized in Example 1.

[0070] Figure 4 SEM and energy dispersive spectroscopy (EDS-Mapping) images of the catalyst synthesized in Example 1.

[0071] Figure 5 SEM and EDS-Mapping of the catalyst synthesized in Comparative Example 1;

[0072] Figure 6SEM and EDS-Mapping of the catalyst used in Comparative Example 3;

[0073] Figure 7 The X-ray diffraction (XRD) patterns of catalysts S1 and S3 synthesized in Example 1 and Comparative Example 2, respectively.

[0074] Figure 8 The X-ray diffraction (XRD) patterns of catalysts S2 and S4 synthesized in Comparative Example 1 and Comparative Example 3, respectively.

[0075] Figure 9 The X-ray diffraction (XRD) patterns of catalysts S5 and S6 synthesized in Comparative Examples 4 and 5, respectively.

[0076] Figure 10 The degradation curves of oxalic acid (OA) catalyzed by catalysts S1, S2, S3, S4, S5, and S6 synthesized in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, respectively, are shown.

[0077] Figure 11 The degradation curves of atrazine (ATZ) catalyzed by catalysts S1, S2, S3, S4, S5, and S6 synthesized in Examples 1, 1, 2, 3, 4, and 5, respectively. Detailed Implementation

[0078] To further illustrate the present invention, the supported ozone catalyst and its preparation method, as well as the spherical ozone catalyst and its application, provided by the present invention are described in detail below with reference to embodiments.

[0079] Example 1

[0080] 1. Weigh 50 mg of FeCl3 and 25 mg of CoCl2 into a 150 mL beaker, add 0.10 g of citric acid, 40 mL of ethanol, 40 mL of acetone, and 20 mL of deionized water. Stir at 1000 rpm for 10 h to form a homogeneous and transparent metal complex solution.

[0081] 2. Next, 2 mg of magnesium nitrate solid and 0.2 g of PVP (MW=30000) were added to the above metal complex solution, and the mixture was stirred until the solution became clear. Then, 0.1 g of urea was added as a slow-release deposition regulator, and the mixture was stirred until the solution became clear.

[0082] 3. Add γ-Al₂O₃ powder to a concentration of 0.2 mol·L⁻¹ -1 In the NaOH solution, the liquid-to-solid ratio is controlled at 10 mL·g -1The carrier was stirred at room temperature or 70 °C for 2 h; the carrier was dispersed in a solution containing 2 wt% silane coupling agent for treatment; after treatment, the carrier was filtered, washed with deionized water, and dried at 80 °C for 10 h to obtain the modified carrier (modified γ-Al2O3).

[0083] Slowly add 20 g of modified γ-Al₂O₃ to the solution obtained in step 2 above, and stir at 1000 rpm for 8 h to allow the metal complex to be uniformly loaded. Adjust the pH of the solution to 9.0 with NaOH.

[0084] 4. Pour the mixture into a Buchner funnel and filter it using a 0.45 μm PES microporous membrane under vacuum of -0.08 MPa. Wash the filter cake twice with deionized water to remove free metal ions.

[0085] 5. After drying the filter cake at 80 °C for 12 h, heat it to 600 °C (7 °C / min) under an argon atmosphere and hold for 4 h to obtain the ozone catalyst monomer.

[0086] 6. The above-mentioned composite catalyst was synthesized multiple times. The catalyst powder and binder were mixed at a mass ratio of (1000:1), wherein the binder consisted of HPC (60%) and polyvinyl alcohol (40%). The mixture was then wetted with water (the water mass was 10% of the powder mass). In the initial stage, 40% of the total water was sprayed, and the mixture was rolled at 30 rpm for 20 min to form primary nucleated particles. Subsequently, the remaining deionized water was sprayed, and granulation was carried out for 60 min under the action of rolling friction (rolling speed 30 rpm, rolling angle 40°), allowing the primary particles to gradually grow and densify. During granulation, the first binder (accounting for 30% of the total binder) was introduced during the powder mixing stage; the second binder (accounting for 70%) was dissolved in the deionized water used for spraying and was simultaneously sprayed during the granulation process to achieve dynamic distribution of the binder during granulation. After granulation, the resulting particles were sieved, and spherical catalyst particles of 2-4 mm were preferably obtained. The sieved particles were dried at 105°C for 5 h, and then dried at room temperature for 24 h. The resulting catalyst was designated as S1.

[0087] Comparative Example 1

[0088] 1. Weigh 25 mg of CoCl2 and 25 mg of FeCl3, add 0.02 g of citric acid, 20 mL of ethanol, and 40 mL of deionized water. Stir to form a clear, homogeneous solution, add 20 g of γ-Al2O3, and stir at 900 rpm for 10 h to ensure uniform loading of the metal complex. Adjust the pH of the solution to 9.0 with NaOH.

[0089] 2. Step 2 is the same as step 4 in Example 1.

[0090] 3. After drying the filter cake at 90 °C for 12 h, heat it to 500 °C (10 °C / min) in air and keep it at that temperature for 4 h to obtain the ozone catalyst monomer.

[0091] 4. The above composite catalyst was synthesized multiple times. The catalyst powder and binder were mixed with polyvinyl alcohol (60%) and amide (40%) at a mass ratio of (1200:1), and then wetted with water (10% of the powder mass). Initially, 40% of the total added water was sprayed, and the mixture was rolled at 30 rpm for 20 min to form primary nucleated particles. Subsequently, the remaining deionized water was sprayed, and granulation was carried out for 40 min under rolling friction (rolling speed 20 rpm, rolling angle 30°), allowing the primary particles to gradually grow and densify. During granulation, the first binder (50% of the total binder) was introduced during the powder mixing stage; the second binder (50%) was dissolved in the sprayed deionized water and simultaneously sprayed during granulation to achieve dynamic distribution of the binder. After granulation, the resulting particles were sieved, with spherical catalyst particles of 2–4 mm being preferred. The sieved particles were dried at 105 °C for 5 h, and then dried at room temperature for 24 h. The resulting catalyst was designated as S2.

[0092] Comparative Example 2

[0093] 1. Step 1 is the same as step 1 in Example 1.

[0094] 2. Slowly add 20 g of SiO2 to the above solution, and stir at 1000 rpm for 8 h to allow the metal complex to be uniformly loaded. Adjust the pH of the solution to 9.0 with NaOH.

[0095] 3. Step 3 is the same as step 4 in Example 1.

[0096] 4. Step 4 is the same as step 5 in Example 1.

[0097] 5. The above-mentioned composite catalyst was synthesized multiple times. The catalyst powder and binder were mixed with HPC (50%) and polyvinyl alcohol (50%) at a mass ratio of (1000:1) and then sprayed with water (10% of the powder mass). In the initial stage, 40% of the total water was sprayed and rolled at a speed of 30 rpm for 20 min to form primary nucleated particles. Subsequently, the remaining deionized water was sprayed, and granulation was carried out for 60 min under the action of rolling friction (rolling speed 30 rpm, rolling angle 40°) to gradually increase the size and densify the primary particles. During granulation, the first binder (accounting for 30% of the total binder) was introduced during the powder mixing stage; the second binder (accounting for 70%) was dissolved in the deionized water used for spraying and was introduced simultaneously during the granulation process to achieve dynamic distribution of the binder during granulation. After granulation, the obtained particles were sieved, and spherical particles of 2-4 mm were preferably obtained. The sieved particles were dried at 105 °C for 5 h, and then dried at room temperature for 24 h. The resulting catalyst was designated as S3.

[0098] Comparative Example 3

[0099] 1. Weigh 50 mg of FeCl3 and add it to a 150 mL beaker. Add 0.05 g of citric acid, 20 mL of ethanol, and 60 mL of deionized water. Stir at 1000 rpm for 10 h to form a homogeneous and transparent metal complex solution.

[0100] 2. Step 2 is the same as step 3 in Example 1.

[0101] 3. Step 3 is the same as step 4 in Example 1.

[0102] 4. Step 4 is the same as step 5 in Comparative Example 1.

[0103] 5. Step 5 is the same as step 6 in Example 1.

[0104] The resulting catalyst is denoted as S4.

[0105] Comparative Example 4

[0106] 1. Weigh 50 mg of FeCl3 and 25 mg of CuCl2 into a 150 mL beaker, add 0.10 g of citric acid, 20 mL of ethanol, and 60 mL of deionized water. Stir at 1000 rpm for 10 h to form a homogeneous and transparent metal complex solution.

[0107] 2. Step 2 is the same as step 3 in Example 1.

[0108] 3. Step 3 is the same as step 4 in Example 1.

[0109] 4. Step 4 is the same as step 5 in Example 1.

[0110] 5. Step 5 is the same as step 6 in Example 1.

[0111] The resulting catalyst is designated as S5.

[0112] Comparative Example 5

[0113] 1. Weigh 5.0 mg of FeCl3 and 2.5 mg of CoCl2 into a 150 mL beaker, add 0.10 g of citric acid, 40 mL of ethanol, 40 mL of acetone, and 20 mL of deionized water. Stir at 1000 rpm for 8 h to form a homogeneous and transparent metal complex solution.

[0114] 2. Step 2 is the same as step 2 in Example 1.

[0115] 3. Slowly add 20 g of modified γ-Al₂O₃ to the solution obtained in step 2 above, and stir at 1000 rpm for 8 h to allow the metal complex to be uniformly loaded. Adjust the pH of the solution to 9.0 with NaOH.

[0116] 4. Step 4 is the same as step 4 in Example 1.

[0117] 5. Step 5 is the same as step 5 in Example 1.

[0118] 6. Step 6 is the same as step 6 in Example 1.

[0119] The resulting catalyst is designated as S6.

[0120] The catalyst materials synthesized above were characterized and their performance tested using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and HPLC.

[0121] The appearances of catalysts S1 and S2 synthesized in Example 1 and Comparative Example 1, respectively, are as follows: Figure 1 As shown, the results indicate that catalysts S1 and S2 exhibit significant color differences due to their different components. The cross-sectional sections and powder morphology of catalysts S1–S6 synthesized in Examples 1, 1, 2, 3, 4, and 5 were observed using SEM, as shown below. Figure 2 As shown, the catalyst synthesized in Example 1 exhibits a uniform surface distribution and a good pore structure. Due to differences in raw materials or reaction conditions during the material synthesis process, the final catalyst surfaces show significant variations.

[0122] Furthermore, catalyst S1 was characterized by TEM, such as Figure 3 As shown, the results indicate that catalyst S1 has a finer microstructure and distribution.

[0123] In addition, we also analyzed Example 1 (e.g., using SEM energy spectrum EDS-Mapping) Figure 4 As shown), Comparative Example 1 (as shown) Figure 5 As shown), Comparative Example 3 (as shown) Figure 6 The elemental composition of the synthesized catalyst is shown in the figure. The microstructure of the catalyst can be seen from the figure, demonstrating that the synthesis method of this invention (Example 1) utilizes organic carbon to assist in the uniform loading of metal on the support surface. After heating with argon gas, the metal coexists with iron-cobalt composite oxides on the catalyst support surface in the form of carbon. The crystal structures of the catalysts obtained in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5 were compared by XRD. Figure 7-9 As can be seen, the active component has a distinct spinel structure. Catalysts obtained by different synthesis methods exhibit differences in crystal structure. S1 and S3 show significant differences due to variations in whether the support is modified; compared to S4, the S2 catalyst shows a distinctly sharp peak due to the increase in metal composition; S6 and S5 show significantly different peak proportions in XRD due to significant differences in metal loading and metal selection.

[0124] In summary, catalyst S1 is supported by modified γ-Al₂O₃ (γ-alumina), and its active component is a composite metal oxide component with Fe and Co as the core elements. Metal promoters, represented by Mg, promote the dispersion of the composite metal during synthesis but are not present in the final catalyst. A homogeneous metal complex system is formed through complexation with ethanol and citric acid, and controlled-release deposition with urea. Finally, after calcination under argon atmosphere, the active phase is formed, ultimately existing in the form of an iron-cobalt composite oxide. The active component is loaded onto the surface of the surface-modified alumina or the inner surface of its pores, which increases the loading capacity and enhances the stability of the loading. Organic carbon (derived from raw material urea and residual organic solvents) not only reduces defects in the modified support but also acts as a promoter carbon component to improve the loading of the active metal. The active component is loaded onto the surface and pore structure of the modified γ-Al₂O₃ support, preserving the original pore structure of the support and the dispersion of the active component.

[0125] Application Example 1

[0126] (1) Using pure oxygen as the gas source, O3 is generated by an ozone generator. The O3 concentration is measured in real time using an ozone concentration detector and the ozone concentration is controlled at 30 mg / L. The ozone flow rate is maintained at 100 mL / min using a gas flow meter.

[0127] (2) The generated O3 is passed into a mixed aqueous solution of catalyst and pollutant. The reaction is carried out in a 250 mL beaker at a temperature of 25±2℃.

[0128] (3) Oxalic acid (OA) was selected as the contaminant in step 2: 200 mL of a 5 mg / L atrazine solution was prepared and added to a beaker. 0.04 g of S1, S2, S3, S4, S5, and S6 provided in the examples and comparative examples were added to the solution, and O3 was bubbled into the solution. Samples were taken at fixed time intervals. After adding ascorbic acid to stop the reaction, the solution was filtered through a 0.22 μm filter membrane, and the concentration of the contaminant was tested using high performance liquid chromatography (HPLC).

[0129] The degradation curve obtained from the test in Example 1 is as follows: Figure 10 As shown in the figure, the ozone system can efficiently degrade OA after adding the catalysts S1-S6 synthesized in the examples, with S1 and S3 exhibiting better ozone catalytic activation performance.

[0130] Application Example 2

[0131] The steps in this application example are the same as in application example 1, except that step (3) is:

[0132] (3) Atrazine (ATZ) was selected as the contaminant in step 2: 200 mL of 5 mg / L oxalic acid solution was prepared and added to a beaker. 0.04 g of S1~S6 provided in the examples and comparative examples, without catalyst and with only alumina were added to the solution respectively. O3 was bubbled into the solution, and samples were taken at fixed time intervals. After adding ascorbic acid to stop the reaction, the solution was filtered through a 0.22 μm filter membrane, and the concentration of the contaminant was tested using high performance liquid chromatography (HPLC).

[0133] from Figure 11 As can be seen, simple ozone oxidation and the addition of alumina have the worst effects. The addition of catalysts S1 to S6 improves the degradation efficiency of pollutants. Among them, catalyst S1 has the highest efficiency in degrading ATZ and has better ozone catalytic activation performance.

[0134] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A supported ozone catalyst, characterized in that, It includes active components, auxiliary carbon components, and a carrier; The support is modified γ-Al2O3 or modified SiO2; The active component and the auxiliary carbon component are dispersed on the outer surface and the inner surface of the pores of the carrier; The active component is an iron-cobalt composite oxide, which has a spinel crystal form; The carbon component of the additive is prepared by calcining urea and citric acid under an inert atmosphere.

2. The supported ozone catalyst according to claim 1, characterized in that, The calcination temperature is 580℃-620℃.

3. The supported ozone catalyst according to claim 1, characterized in that, The carrier is obtained by sequentially treating γ-Al2O3 or SiO2 powder with sodium hydroxide solution and a modifier; The modifier is selected from silane coupling agents, organic amine compounds, or polyol compounds.

4. The method for preparing the ozone catalyst according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Mix soluble iron salt, soluble cobalt salt, ethanol, citric acid, acetone and water to react and obtain metal complex system S1; (2) Mix S1 with soluble metal salt, structure modifier and urea to obtain system S2; (3) Mix and impregnate modified γ-Al2O3 or modified SiO2 with system S2 to obtain system S3; (4) After filtering and drying the system S3 in sequence, it is calcined under an inert atmosphere to prepare the supported ozone catalyst.

5. The preparation method according to claim 4, characterized in that, The calcination temperature is 580℃-620℃.

6. The preparation method according to claim 4, characterized in that, The molar amount of iron in the soluble iron salt is ≥0.31 mmol; The molar amount of cobalt in the soluble cobalt salt is ≥0.19 mmol; The ratio of ethanol to citric acid is (30-50) mL: (0.05-0.2) g.

7. The preparation method according to claim 4, characterized in that, The soluble iron salt is selected from ferric chloride, ferric nitrate, or ferric acetate; The soluble cobalt salt is selected from cobalt chloride, cobalt nitrate, cobalt acetate, or cobalt sulfate; The soluble auxiliary metal salt is selected from magnesium sulfate or magnesium nitrate; The structure modifier is selected from one or more of polyvinylpyrrolidone, polyethylene glycol, and polyacrylic acid.

8. A spherical ozone catalyst, characterized in that, It is prepared by mixing and granulating an ozone catalyst obtained by any one of claims 1-3 or by any one of claims 4-7 with a binder; The spherical ozone catalyst has a particle size of 2-4 mm.

9. The spherical ozone catalyst according to claim 8, characterized in that, The mass ratio of the supported ozone catalyst to the binder is (500-2000):1; The adhesive is composed of one or more of hydroxypropyl cellulose, polyvinyl alcohol, and amide.

10. The use of the spherical ozone catalyst according to claim 8 or 9 in the degradation of oxalic acid or atrazine.

Images