Submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst and preparation method thereof

Abstract

The invention provides a submicron fly ash based Mn-Ce-Bi ternary composite ozone catalyst and a preparation method thereof. The preparation method comprises the following specific steps: (1) placing dried fly ash in a ball milling tank according to a certain amount, adding a proper amount of deionized water according to a solid-to-liquid ratio, and carrying out ball milling for 6 hours by using a wet ball milling technology to obtain micron-sized fly ash (namely a first product); (2) taking a certain amount of the first product, respectively adding ZnCl2 solutions with different concentrations according to a certain solid-to-liquid ratio, and continuing ball milling for 3 hours to obtain a submicron fly ash carrier (a second product); (3) weighing a certain amount of manganese nitrate Mn (NO3) 2.4 H2O, cerium nitrate Ce (NO3) 3.6 H2O and bismuth nitrate Bi (NO3) 3.5 H2O, adding deionized water, and fully mixing and stirring to prepare a precursor solution (a third product); (4) adding the second product into the precursor solution, uniformly stirring, performing ultrasonic treatment, and dipping at room temperature to obtain a fourth product; and (5) drying the fourth product in a drying box, and finally calcining the dried sample in a muffle furnace to obtain the final product Mn-Ce-Bi / FA ternary composite catalyst. The fly ash-based ozone catalyst prepared by the method is large in specific surface area, greatly improved in adsorption capacity, simple in preparation process, wide in raw material source and low in price.

Description

Technical Field

[0001] The present invention relates to the technical field of purification of organic pollutants in water bodies, and particularly to a submicron fly ash-based supported ozone catalyst and a preparation method thereof. Technical Background

[0002] With the acceleration of the social industrialization process, the water pollution problems caused by various industrial wastewaters discharged in industrial production (such as boiler wastewater, printing and papermaking wastewater, desulfurization wastewater, and pharmaceutical wastewater, etc.) have become increasingly prominent. According to relevant statistics, the annual discharge of harmful substances in the global water body has exceeded 2.5 million tons, among which the discharge of industrial production wastewater dominates, containing a large amount of organic matter, heavy metals, and micro-pollutants, posing a huge threat to the ecological environment and human health. Organic pollution not only reduces the availability of water resources but also exacerbates the burden on the natural environment of the pollution source, and most organic pollutants are toxic, and long-term accumulation will cause irreversible damage to the ecological environment. In view of the risks they may pose to the water ecological environment and human health, it is very urgent to develop efficient technologies for treating industrial wastewater.

[0003] Ozone technology decomposes harmful substances through catalytic oxidation to improve water quality and protect the environment. In industrial wastewater treatment, ozone technology can effectively remove harmful substances such as organic matter and heavy metals, and has attracted more and more attention due to its advantages of high efficiency, no secondary pollution, and non-toxicity. Advanced oxidation processes (AOPs) based on ozone (O 3 ) activation usually generate highly reactive oxygen species (ROS), such as ·OH, O 2 - · and 1 O 2 , which have been proven to be an effective and environmentally friendly method for removing refractory pollutants. Although O 3 has a high redox potential (E 0 = 2.07V), but independent O 3 shows strict selectivity and only attacks the nucleophilic sites of the aromatic ring. In order to improve the selectivity limitation of ozone, the heterogeneous catalytic ozonation process formed by combining ozone with a solid catalyst has attracted much attention recently. However, current ozone catalysts face challenges such as limited specific surface area, poor adsorption performance, and high preparation cost.

[0004] Fly ash (FA), as a product after the combustion of coal-fired boilers, has a spherical appearance, a smooth surface, and a porous structure. Its main components are SiO 2 , Al 2 O 3 , Fe 2 O 3and MgO, etc., are alkaline. If fly ash is not properly treated, it will generate dust, pollute the atmosphere and water quality, and endanger human health. Due to its porous characteristics, fly ash exhibits excellent adsorption performance and is therefore widely used in the preparation of adsorbents and catalyst carriers. In practical applications, fly ash can improve its hydration ability through activation technology and be applied to fields such as chemical wastewater treatment, cement, and concrete production. Currently, fly ash carriers have problems such as a relatively low specific surface area (less than 50m 2 / g), insufficient loading rate of active components (generally less than 20%), and poor dispersion of active components due to low porosity. Moreover, a single-metal or dual-metal system (such as Mn / FA, Ce / FA) is generally adopted, resulting in limited catalytic efficiency and a TOC removal rate that is difficult to exceed 70%. Activation technologies can be divided into chemical activation, mechanical activation, mechanochemical activation, and physical and chemical activation. The main methods of mechanical activation are sorting and ball milling. Ball milling can enhance its chemical reactivity without changing the chemical composition of fly ash and affect the dispersion characteristics of fly ash, such as an increase in specific surface area, adjustment of particle size distribution, and changes in particle mineral composition, morphology, and shape. Summary of the Invention

[0005] The present invention provides a submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst and a preparation method thereof. The present invention has good ozone catalytic performance, promotes the reaction of ozone to decompose organic pollutants in water through the ozone catalyst, thereby realizing the effective removal of organic pollutants in water bodies. The present invention is low in cost, provides a new idea for the comprehensive utilization of fly ash, and has good economic and environmental benefits.

[0006] To achieve the above invention object, the present invention provides the following technical solutions:

[0007] Co-wet grind fly ash and deionized water to initially obtain a micron-sized fly ash carrier; use the initially obtained micron-sized fly ash carrier and ZnCl 2 solution to co-wet grind to obtain a submicron-sized modified fly ash as the carrier; use metal oxides attached to the alkali-modified fly ash carrier by ultrasonic impregnation method as the active components.

[0008] In the present invention, the metal oxides include MnO 2 , Mn 2 O 3 , MnO, CeO 2 , Ce 2 O 3 , Bi 2 O 3 .

[0009] The present invention provides a submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst and a preparation method thereof, comprising the following steps:

[0010] (1) placing a certain amount of dried raw fly ash in a ball mill, adding an appropriate amount of deionized water according to a predetermined solid-liquid ratio, and performing a wet ball milling process for 6 hours to grind the fly ash to a particle size that meets the requirements, thereby obtaining micron-grade fly ash, with a particle size distribution of more than 80% under a 2-micron sieve (the first product);

[0011] (2) Weigh 10 g of the first product and add 50 mL of ZnCl at different concentrations according to a certain solid-liquid ratio. 2 The ball milling was continued for 3 h in the solution. After the ball milling process was completed, the product was thoroughly rinsed five times with deionized water and then dried to finally obtain a submicron fly ash carrier with a particle size distribution of more than 90% under a 0.5 μm sieve (i.e., the second product);

[0012] (3) Weigh a certain amount of manganese nitrate Mn(NO 3 ) 2 ·4H 2 O, cerium nitrate Ce(NO 3 ) 3 6H 2 O. Bismuth nitrate Bi(NO 3 ) 3 ·5H 2 O, and adding deionized water and mixing thoroughly to prepare an active component precursor solution (the third product);

[0013] (4) adding the second product to the precursor solution (third product), stirring evenly, ultrasonically treating for 1 hour, and immersing at room temperature for 4 hours to obtain a fourth product;

[0014] (5) The fourth product was placed in a drying oven at 105°C and dried for 6 h. Finally, the dried sample was placed in a muffle furnace and calcined at different temperatures for 3 h to obtain the final product, Mn-Ce-Bi / FA ternary composite catalyst.

[0015] Preferably, in step (2), the modified solution ZnCl 2 The concentrations of ZnCl are 0, 0.05, 0.10, 0.25, and 0.50 mol / L, respectively, and the solid-liquid ratio is 1:5; further preferably, ZnCl 2 The concentration is 0.25mol / L.

[0016] In the present invention, in step (3), the precursor solution is a solution of manganese nitrate, cerium nitrate, and bismuth nitrate, and the molar ratios of Mn:Ce:Bi are -1:1:1, 2:1:1, 3:1:1, and 2:2:1, respectively; further preferably, the molar ratio of Mn:Ce:Bi is 2:1:1.

[0017] In step (4), the Mn-Ce-Bi / FA composite ozone catalyst prepared by us is denoted as Mn-Ce-Bi(X) / FA, where X represents the mass fractions of Mn, Ce, and Bi in the catalyst, which are 10%, 20%, 30%, and 40% respectively; in particular, when the mass fraction is 30%, the catalyst performance is better.

[0018] Preferably, in the said step (5), the calcination temperatures are 350, 450, 550, and 650 °C respectively; more preferably, the calcination temperature is 550 °C.

[0019] The beneficial effects brought by the present invention are as follows:

[0020] 1. The concept of the present invention is unique. Fly ash itself does not have ozone catalytic ability. Through the modification process, the mineral crystal phase of fly ash can be destroyed, thereby improving its loading capacity for active components, achieving the resource recycling effect of "treating waste with waste".

[0021] 2. The secondary wet ball milling technology is adopted to wet mill fly ash and deionized water together to destroy the physical structure of fly ash and open the internal pores, initially obtaining a micron-level fly ash carrier. Utilizing the pore-forming function of ZnCl 2 solution, the initially obtained micron-level fly ash carrier and ZnCl 2 solution are wet milled together, which can greatly improve the porosity of fly ash while significantly reducing the fineness of fly ash, further increasing the specific surface area and loading capacity of the modified fly ash, making it reach the sub-micron level (below 500 nm, attached Figure 1 ), achieving efficient loading of active components (attached Figure 2 ). Compared with using expensive carriers available on the current market, using modified fly ash as a carrier can significantly reduce the cost expenditure for catalyst preparation.

[0022] 3. The preparation method of the fly ash-based ozone catalyst adopted in the present invention is simple and feasible. The prepared Mn-Ce-Bi / FA fly ash-based ternary supported ozone catalyst can effectively promote the oxidation of organic pollutants in water by ozone, providing a feasible direction for the high-value utilization of fly ash, and at the same time promoting the development of economic and environmental-friendly ozone catalysts.

[0023] 4. The specific surface area of the catalyst prepared by the method of the present invention reaches 150 m 2 / g (BET test), and the loading rate of active components is increased to 30% - 40%; the TOC removal rate for simulated printing and dyeing wastewater reaches 92% (compared with 70% of traditional catalysts), and the efficiency still remains above 85% after 5 cycles. Description of the Drawings

[0024] To more clearly illustrate the technical solution of the present invention, the following will briefly introduce the attached drawings required in the technical description of the present invention. In the attached drawings:

[0025] Figure 1 shows the fly ash carrier after ball milling of the present invention. After being modified with ZnCl 2 analysis by scanning electron microscopy (SEM) shows that the surface porosity of the fly ash carrier increases significantly, and the pore structure is optimized. The particle size distribution of the modified fly ash carrier is 200 - 500 nm. The modified fly ash has well-developed pores and significantly improved adsorption performance.

[0026] Figure 2 is the X-ray diffraction (XRD) pattern of the ozone catalyst after loading the active components. The active components (MnO 2 、CeO 2 、Bi 2 O 3 ) are uniformly loaded on the surface of the carrier without agglomeration. Specific implementation method

[0028] The present invention provides a fly ash-based supported ozone catalyst, which is characterized by comprising:

[0029] Mix fly ash with deionized water and perform wet milling treatment to initially obtain a micron-sized fly ash carrier; use the submicron-sized modified fly ash obtained by co-wet milling the initially obtained micron-sized fly ash carrier and ZnCl 2 solution as the carrier; adopt the ultrasonic impregnation method to uniformly attach metal oxides to the alkali-modified fly ash carrier as the active components of the catalyst.

[0030] In the present invention, the metal oxides include MnO 2 、Mn 2 O 3 、MnO、CeO 2 、Ce 2 O 3 .

[0031] The present invention provides a preparation method of a fly ash-based supported ozone catalyst, comprising the following steps:

[0032] (1) Put a certain amount of dried original fly ash (Baoding Thermal Power Plant) into a ball milling tank, add an appropriate amount of deionized water according to a certain solid-liquid ratio, and use wet ball milling technology to ball mill for 6 h to grind the fly ash to a required particle size to obtain micron-sized fly ash (the first product);

[0033] (2) Weigh 10 g of the first product, and add 50 mL of ZnCl with different concentrations according to a certain solid-liquid ratio 2In the solution, continue ball milling for 3 h. After the ball milling is completed, rinse repeatedly with deionized water for 5 times and then dry to obtain a submicron fly ash carrier (the second product).

[0034] (3) Weigh a certain amount of manganese nitrate Mn(NO 3 ) 2 ·4H 2 O, cerium nitrate Ce(NO 3 ) 3 ·6H 2 O, and bismuth nitrate Bi(NO 3 ) 3 ·5H 2 O, and add deionized water and mix and stir well to prepare an active component precursor solution (the third product).

[0035] (4) Add the second product to the precursor solution (the third product), stir evenly and then perform ultrasonic treatment for 1 h, and impregnate at room temperature for 4 h to obtain the fourth product.

[0036] (5) Place the fourth product in a drying oven and dry at 105 °C for 6 h. Finally, place the dried sample in a muffle furnace and calcine at different temperatures for 3 h to obtain the final product - the Mn-Ce-Bi / FA ternary composite catalyst.

[0037] Preferably, in the step (2), the concentrations of the modification solution ZnCl 2 are 0, 0.05, 0.10, 0.25, 0.50 mol / L respectively, and the solid-liquid ratio is 1:5; more preferably, the concentration of ZnCl 2 is 0.25 mol / L.

[0038] In the present invention, in the step (3), the precursor solution is a manganese nitrate, cerium nitrate, and bismuth nitrate solution, and the molar ratios of Mn:Ce:Bi are -1:1:1, 2:1:1, 3:1:1, 2:2:1 respectively; more preferably, the molar ratio of Mn:Ce:Bi is 2:1:1.

[0039] Preferably, in the step (4), the Mn-Ce-Bi / FA composite ozone catalyst is denoted as Mn-Ce-Bi(X) / FA (X = 10%, 20%, 30%, 40%, where X represents the mass fraction of Mn, Ce, and Bi in the catalyst, %).; more preferably, the mass fractions of Mn, Ce, and Bi in the catalyst are 30%.

[0040] Preferably, in the step (5), the calcination temperatures are 350, 450, 550, 650 °C respectively; more preferably, the calcination temperature is 550 °C.

[0041] Control Example 1 (without ZnCl 2Modification):

[0042] (1) Preparation of the first product

[0043] Weigh 20 g of the original fly ash into a ball milling jar, add 100 mL of deionized water, adjust the rotation speed of the planetary ball mill to 550 rpm, and continuously ball mill for 3 h. After the ball milling is completed, dry it in an oven at 105 °C for 6 h to obtain fly ash at the micron level (the first product).

[0044] (2) Modification of fly ash

[0045] Weigh 10 g of the first product, add deionized water according to a solid-liquid ratio of 1:5, and continue ball milling for 1 h. After the ball milling is completed, dry it in an oven at 105 °C for 6 hours to obtain a submicron fly ash carrier (i.e., the second product).

[0046] (3) Preparation of the precursor solution

[0047] Weigh 5.02 g of Mn(NO 3 ) 2 ·4H 2 O into different beakers. According to the molar ratio of Mn:Ce:Bi of 2:1:1, add 4.32 g of Ce(NO 3 ) 3 ·6H 2 O and 4.85 g of Bi(NO 3 ) 3 ·5H 2 O respectively. After dissolving them with dilute nitric acid, transfer them to a 500 mL volumetric flask and make up to the mark to prepare the required active component precursor solution (i.e., the third product).

[0048] (4) Preparation of the fourth product

[0049] Measure 100 mL of different precursor solutions, add different masses of modified fly ash (the second product) according to the mass fractions of Mn, Ce, and Bi in the catalyst being 30% respectively. After stirring evenly, carry out ultrasonic treatment for 1 h and impregnate at room temperature for 4 h to obtain the fourth product.

[0050] (5) Preparation of the Mn-Ce-Bi / FA ternary supported ozone catalyst

[0051] Place the fourth product in a drying oven and dry it at 105 °C for 6 h. Place the dried sample in a muffle furnace and use the programmed heating technique to heat it to 550 °C at a rate of 5 °C / min. At this temperature, continuously calcine for 3 h, cool to room temperature and then take it out to obtain the final product - the Mn-Ce-Bi / FA ternary supported ozone catalyst 1.

[0052] ZnCl was not used2 Modified, the specific surface area of the catalyst is 60 m 2 / g, and the TOC removal rate is 72%.

[0053] Comparative Example 2 (bimetallic system):

[0054] (1) Preparation of the first product

[0055] Weigh 20 g of raw fly ash into a ball milling jar, add 100 mL of deionized water, adjust the rotation speed of the planetary ball mill to 550 rpm, and continuously ball mill for 3 h. After the ball milling is completed, dry it in an oven at 105 °C for 6 h to obtain fly ash at the micron level (the first product).

[0056] (2) Modification of fly ash

[0057] Weigh 10 g of the first product, and according to the solid-liquid ratio of 1:5, add it to 50 mL of ZnCl solutions with different concentrations respectively. The concentration of the ZnCl solution is 0.25 mol / L, and continue to ball mill for 1 h. After the ball milling is completed, rinse it repeatedly with deionized water 5 times, and dry it in an oven at 105 °C for 6 hours to obtain a submicron fly ash carrier (i.e., the second product). 2 solution, ZnCl 2 solution

[0058] (3) Preparation of the precursor solution

[0059] Weigh 5.02 g of Mn(NO 3 ) 2 ·4H 2 O into different beakers. According to the Mn:Ce molar ratio of 2:1, add 4.32 g of Ce(NO 3 ) 3 ·6H 2 O. After dissolving it with dilute nitric acid, transfer it to a 500 mL volumetric flask and make up to the mark to prepare the required active component precursor solution (i.e., the third product).

[0060] (4) Preparation of the fourth product

[0061] Measure 100 mL of different precursor solutions, and according to the mass fractions of Mn and Ce in the catalyst being 30% respectively, add the modified fly ash (the second product), stir evenly and then carry out ultrasonic treatment for 1 h, and impregnate at room temperature for 4 h to obtain the fourth product.

[0062] (5) Preparation of the Mn-Ce / FA ternary supported ozone catalyst

[0063] The fourth product was placed in a drying oven and dried at 105 °C for 6 h. The dried sample was placed in a muffle furnace, and the temperature was increased to 550 °C at a rate of 5 °C / min using a programmed temperature increase technique. At this temperature, it was calcined for 3 h, cooled to room temperature, and then taken out to obtain the final product, the Mn-Ce / FA ternary supported ozone catalyst.

[0064] Only loaded with Mn-Ce bimetal, the TOC removal rate was 82%.

[0065] Example 3:

[0066] (1) Preparation of the first product

[0067] Weigh 20 g of the original fly ash into a ball milling jar, add 100 mL of deionized water, adjust the rotation speed of the planetary ball mill to 550 rpm, and continuously ball mill for 3 h. After the ball milling is completed, dry it in an oven at 105 °C for 6 h to obtain micron-sized fly ash (the first product).

[0068] (2) Modification of fly ash

[0069] Weigh 10 g of the first product, and according to a solid-liquid ratio of 1:5, add it to 50 mL of ZnCl 2 solutions with different concentrations respectively. The concentrations of the ZnCl 2 solutions are 0.05, 0.10, 0.25, and 0.50 mol / L respectively, and continue to ball mill for 1 h. After the ball milling is completed, rinse it with deionized water repeatedly for 5 times and dry it in an oven at 105 °C for 6 hours to obtain a submicron fly ash carrier (i.e., the second product).

[0070] When the concentration of the ZnCl 2 solution is 0.25 mol / L, the proportion of particles smaller than 0.5 microns in the prepared submicron fly ash carrier is the highest, reaching 90.8%, and the specific surface area of the finally prepared catalyst reaches 150 m 2 / g.

[0071] (3) Preparation of the precursor solution

[0072] Weigh 5.02 g of Mn(NO 3 ) 2 ·4H 2 O into different beakers. According to different Mn:Ce:Bi molar ratios (1:1:1, 2:1:1, 3:1:1, 2:2:1), add 8.64, 4.32, 2.16, and 8.64 g of Ce(NO 3 )3·6H 2 O, 9.70, 4.85, 2.43, and 4.85 g of Bi(NO 3 ) 3 ·5H 2O. After dissolving it with dilute nitric acid, transfer it to a 500 - milliliter volumetric flask and make up the volume to the mark, thus preparing the required active - component precursor solution (i.e., the third product).

[0073] (4) Preparation of the fourth product

[0074] Measure 100 mL of different precursor solutions. According to the mass fractions of Mn, Ce, and Bi in the catalyst being 10%, 20%, 30%, and 40% respectively, add different masses of modified fly ash (the second product). After stirring evenly, conduct ultrasonic treatment for 1 h and impregnate at room temperature for 4 h to obtain the fourth product.

[0075] (5) Preparation of the Mn - Ce - Bi / FA ternary - supported ozone catalyst

[0076] Place the fourth product in an oven and dry it at 105°C for 6 h. Then place the dried sample in a muffle furnace. Using the programmed - temperature - rising technique, heat it to 350, 450, 550, and 650°C at a rate of 5°C / min respectively. At these temperatures, calcine it continuously for 3 h. After cooling to room temperature, take it out to obtain the final product - the Mn - Ce - Bi / FA ternary - supported ozone catalyst.

[0077] When the preparation conditions are: ZnCl 2 with a concentration of 0.25 mol / L, Mn:Ce:Bi = 2:1:1, the mass fractions of Mn, Ce, and Bi being 30%, and the calcination temperature being 550°C, the prepared catalyst has the best performance. The specific surface area of the catalyst reaches 150 m 2 / g, and the TOC removal rate reaches 95%. After 5 - cycle use of the catalyst, the TOC removal rate remains 85%, and ICP - MS detection shows that the metal dissolution rate < 1%.

[0078] As described above, it is only the specific implementation manners protected by this invention patent. However, the protection scope of this invention patent is not limited thereto. Any person skilled in the art within the technical scope disclosed by this invention patent, according to the technical solution and inventive concept of this invention patent, makes equivalent substitutions or changes, and should be covered within the protection scope of this invention patent.

Claims

1. A submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst, characterized in that: The catalyst is obtained by wet ball milling, ZnCl2 solution modification, ultrasonic impregnation of metal oxide precursor solution and calcination of fly ash from power plants; the metal oxide active components include MnO2, Mn2O3, MnO, CeO2, Ce2O3, Bi2O3, and the mass fraction of Mn, Ce and Bi in the catalyst is 30%, and the specific surface area of ​​the catalyst reaches 150m 2 / g.

2. A method for preparing a submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst, characterized in that: The following steps are involved: (1) dry fly ash and deionized water were wet-milled at a solid-liquid ratio of 1:5 for 6 hours to obtain micron-sized fly ash, with a distribution of more than 80% under a 2-micron sieve; (2) The product obtained in step (1) is subjected to secondary wet ball milling with 0.05-0.50 mol / L ZnCl2 solution at a solid-liquid ratio of 1:5 for 3 hours, and after washing and drying, a submicron fly ash carrier is obtained, with a distribution of more than 90% under a 0.5 micron sieve. (3) preparing a mixed precursor solution of Mn(NO3)2·4H2O, Ce(NO3)3·6H2O, and Bi(NO3)3·5H2O, wherein the molar ratio of Mn:Ce:Bi is 1:1:1 or 2:1:1 or 3:1:1; (4) The carrier of step (2) is immersed in the precursor solution, ultrasonically treated for 1 hour and then immersed at room temperature for 4 hours. After drying, it is calcined at 350-650° C. for 3 hours to obtain a submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst.

3. The method for preparing the submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst according to claim 2, characterized in that: The concentration of the ZnCl2 solution is 0.05-0.50 mol / L, preferably 0.25 mol / L, and the solid-liquid ratio is 1:

5.

4. The method for preparing the submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst according to claim 2, characterized in that: The molar ratio of Mn:Ce:Bi in the precursor solution can be other ratios in the range of 1:1:1 to 3:1:1, but the catalyst has the best performance when the molar ratio is 2:1:

1.

5. The method for preparing the submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst according to claim 2, characterized in that: The active component loading of Mn, Ce and Bi accounts for 30% of the mass fraction of the catalyst, and the specific surface area of ​​the catalyst reaches 150m 2 / g.

6. The method for preparing the submicron fly ash-based Mn-Ce-Bi ternary composite ozone catalyst according to claim 2, characterized in that: The calcination temperature may be other temperatures within the range of 350-650°C, but the catalyst has the best performance when the calcination temperature is 550°C.

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