Ozone catalyst, method for preparing the same, and use thereof

Abstract

The application provides an ozone catalyst and a preparation method and application thereof. The ozone catalyst is prepared based on the preparation method, the preparation process is simple, energy consumption is low, the ozone catalyst can have good mechanical properties and wastewater treatment effect, and is particularly suitable for treating organic wastewater generated in the field of coal chemical industry. The preparation method comprises the following steps: 1) taking porous cordierite as a carrier, pretreating the carrier in an alkaline solution, and then cleaning and drying; 2) coating a coating liquid on the carrier pretreated in step 1); the coating liquid comprises manganese dioxide and silica sol; and 3) drying the carrier coated with the coating liquid in step 2) at 120-200 DEG C, so as to obtain an ozone catalyst with a coating layer formed on the carrier.

Description

Technical Field

[0001] This invention relates to ozone catalysts suitable for the treatment of organic wastewater, specifically to an ozone catalyst, its preparation method, and its application. Background Technology

[0002] Advanced oxidation technologies (AOCs) are highly efficient wastewater treatment technologies that decompose organic matter in water by generating highly oxidizing hydroxyl radicals, which then mineralize it into CO2 and H2O. Ozone catalytic oxidation is one of the most widely used AOC methods in engineering applications. Ozone catalytic oxidation technologies often employ heterogeneous ozone catalysts, primarily supported particulate catalysts, which are packed into a reaction tower in a fixed-bed configuration for a gas-liquid-solid three-phase reaction. However, solid particles are prone to pulverization and breakage during application, presumably due to particle collisions caused by airflow and water flow, resulting in mechanical damage to the catalyst. Furthermore, fluid flow can easily create channeling between particles, reducing catalyst utilization.

[0003] Patent application CN202010067144.4 describes a highly efficient heterogeneous ozone catalyst for treating acidic industrial wastewater and its preparation method. This heterogeneous ozone catalyst consists of a cordierite honeycomb ceramic support and γ-Al₂O₃ and the active component Pd-CeOx supported on the surface of the cordierite honeycomb ceramic support. The specific preparation method includes: impregnating the cordierite honeycomb ceramic sequentially in γ-Al₂O₃ sol, CeOx sol, and lead nitrate solution, followed by drying and calcination to obtain the heterogeneous ozone catalyst.

[0004] Patent application CN201711065843.X relates to a method for preparing a heterogeneous ozone catalyst, its products, and applications. The preparation method mainly includes hydrothermal growth of nickel oxide nanosheets on the surface of cordierite honeycomb ceramics and growth of zinc oxide nanorods on the surface of cordierite honeycomb ceramics on which nickel oxide nanosheets have been grown.

[0005] Patent application CN201510508937.4 discloses a high-salt ozone resistant catalyst, which is composed of the following components in parts by weight: 88.7-91.3 parts of activated alumina particles with a particle size of 2-4 mm, 1.4-1.6 parts of copper oxide, 0.8-1.2 parts of titanium dioxide, 4-7 parts of polyethylene glycol, and 1.9-2.1 parts of polyvinyl alcohol. The preparation process involves mixing the components in a mixer to prepare a coating solution, immersing the activated alumina particles in the coating solution, and then drying and calcining them to obtain the high-salt ozone resistant catalyst.

[0006] Existing heterogeneous ozone catalyst preparation processes suffer from drawbacks such as complex processes, unsatisfactory catalyst mechanical properties, and insufficient ozone utilization. Particularly when using ozone catalysts to treat organic wastewater from the coal chemical industry, the complex composition of this wastewater, typically containing high levels of salt and organic matter, places higher demands on the mechanical properties and catalytic activity of the ozone catalyst. Developing an ozone catalyst suitable for organic wastewater, particularly from the coal chemical industry, and capable of providing a relatively simple preparation process that balances good mechanical properties with effective wastewater treatment, is one of the critical technical challenges in this field that urgently needs to be overcome. Summary of the Invention

[0007] This invention provides an ozone catalyst, its preparation method, and its application. The ozone catalyst prepared by the method of this invention has a simple preparation process, low energy consumption, and the obtained ozone catalyst can achieve both good mechanical properties and wastewater treatment effect, and is particularly suitable for treating organic wastewater generated in the coal chemical industry.

[0008] To achieve its objective, the present invention provides the following technical solution:

[0009] This invention provides a method for preparing an ozone catalyst, comprising the following steps:

[0010] 1) Using porous cordierite as a carrier, the carrier is pretreated in an alkaline solution, and then cleaned and dried;

[0011] 2) Coating the pretreated carrier in step 1) with a coating solution; the coating solution contains manganese dioxide and silica sol;

[0012] 3) Dry the carrier coated with the coating liquid in step 2) at 120-200°C to obtain an ozone catalyst with a coating layer formed on the carrier.

[0013] In some embodiments, in step 1), the pH of the alkaline solution is 10-12;

[0014] Preferably, in step 1), the pretreatment is carried out at 60-100°C, and the pretreatment time is preferably 6-10 hours.

[0015] Preferably, the alkaline solution is selected from aqueous solutions of sodium hydroxide and / or potassium hydroxide.

[0016] In some embodiments, in the coating solution of step 2), the mass ratio of water, silica sol and manganese dioxide is 50-150:12.5-37.5:100, wherein the amount of silica sol is calculated based on the silica content in the silica sol.

[0017] In some embodiments, in step 2), the carrier pretreated in step 1) is repeatedly immersed in the coating solution to coat the carrier with the coating solution.

[0018] In some embodiments, in step 3), the drying is carried out at 120-150°C.

[0019] In some embodiments, the coating layer comprises 2%-10% by weight, preferably 3%-5%, based on the total weight of the ozone catalyst.

[0020] In some embodiments, in the coating liquid of step 2), the mass ratio of water, silica sol and manganese dioxide is 50-150:20-30:100, wherein the amount of silica sol is calculated based on the silica content in the silica sol.

[0021] In step 3), the drying is carried out at 120-150°C;

[0022] The coating layer comprises 3%-5% of the total weight of the ozone catalyst.

[0023] In some embodiments, the porous cordierite is honeycomb cordierite;

[0024] And / or, the carrier has a regularly shaped form.

[0025] The present invention also provides an ozone catalyst, wherein the ozone catalyst uses porous cordierite as a support, and a coating layer is formed on the support, the coating layer comprising manganese dioxide and silicon dioxide;

[0026] Preferably, the coating layer comprises 2%-10% by weight, more preferably 3-5%, based on the total weight of the ozone catalyst.

[0027] Preferably, in the coating layer, the mass ratio of manganese dioxide to silicon dioxide is 100:12.5 to 100:37.5;

[0028] Preferably, the porous cordierite is honeycomb cordierite;

[0029] Preferably, the carrier has a regularly shaped form;

[0030] More preferably, the ozone catalyst is prepared by the preparation method according to any one of claims 1-8.

[0031] The present invention also provides an application in which the ozone catalyst obtained by the preparation method described above or the ozone catalyst described above is used in the treatment of organic wastewater; in particular, the wastewater is organic wastewater generated in the coal chemical industry.

[0032] The technical solution provided by this invention has the following beneficial effects:

[0033] The preparation method provided by this invention pretreats the carrier with an alkaline solution, loads the active material manganese dioxide by coating, and dries it in one step by low temperature drying. It has the characteristics of simple preparation process, low energy consumption, and easy and quick acquisition of ozone catalyst. At the same time, the ozone catalyst provided has good catalytic reaction efficiency, good mechanical properties, and is not easy to fall off, which helps to reduce mechanical loss. Attached Figure Description

[0034] Figure 1 The diagram shown is a schematic of the experimental apparatus for catalytic ozonation.

[0035] Figure 2 The image shown is a schematic diagram of an ozone catalyst obtained in one embodiment.

[0036] Figure 1 The following are the labels in the attached diagram: 1. Ozone generator, 2. Ozone concentration detector, 3. Reactor, 4. Catalyst. Detailed Implementation

[0037] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0039] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in this technical field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0040] This invention provides a method for preparing an ozone catalyst, which mainly includes the following steps:

[0041] 1) Using porous cordierite as a carrier, the carrier is pretreated in an alkaline solution, then cleaned and dried;

[0042] 2) Coat the carrier after the pretreatment in step 1) with a coating solution; the coating solution contains manganese dioxide and silica sol;

[0043] 3) Dry the carrier coated with the coating liquid in step 2) at 120-200℃ to obtain an ozone catalyst with a coating layer formed on the carrier.

[0044] The preparation method of the present invention uses an alkaline solution to pretreat the carrier, and then forms a coating layer by one-step coating with a coating solution containing manganese dioxide and silica sol. The ozone catalyst is then prepared by one-step drying at low temperature. This method has the advantages of short process flow, simple operation, low energy consumption, and the ozone catalyst obtained can well balance mechanical properties and catalytic activity. It is used to treat organic wastewater, especially high-salt organic wastewater in the coal chemical industry. It has the characteristics of high COD removal efficiency, good mechanical properties, not easy to fall off and pulverize, and easy to reuse.

[0045] In the preparation method of this invention, in step 1), the porous cordierite support is pretreated in an alkaline solution. This pretreatment facilitates the formation of a uniform and robust coating layer on the support surface by the subsequent coating solution, thereby improving mechanical properties and catalytic activity. In some preferred embodiments, the pH of the alkaline solution in step 1) is 10-12. In some preferred embodiments, in step 1), the pretreatment is carried out at 60-100℃, preferably 60-90℃, for a preferred time of 6-10 hours. Pretreatment at the preferred temperature improves the pretreatment effect and yields a catalyst with better performance. In some embodiments, the alkaline solution is selected from aqueous solutions of sodium hydroxide and / or potassium hydroxide.

[0046] In the preparation method of this invention, in step 2), the coating solution used contains manganese dioxide and silica sol, and also contains an appropriate amount of water; preferably, in the coating solution of step 2), the mass ratio of water, silica sol and manganese dioxide is 50-150:12.5-37.5:100, wherein the amount of silica sol is based on the silica content in the silica sol. Using a coating solution with the preferred composition is beneficial for uniformly and relatively firmly coating the active component manganese dioxide onto the carrier surface, which is beneficial for improving catalyst activity and mechanical properties, and the resulting catalyst coating layer is less prone to peeling off. In a preferred embodiment, the coating solution can be ball-milled before being used for coating in step 3).

[0047] In the preparation method of the present invention, in step 2), the coating liquid is applied to the carrier by coating, that is, the coating liquid is applied to the outer surface and inner surface (e.g., the surface of internal pores) of the carrier. Preferably, the coating liquid is applied to the carrier by immersing the carrier pretreated in step 1) in the coating liquid and repeating the immersion operation multiple times. This coating method is beneficial to ensure that both the inner and outer surfaces of the carrier are in uniform contact with the coating liquid and to uniformly form a coating liquid layer.

[0048] In the preparation method of this invention, step 3) involves drying the carrier coated with the coating solution in step 2) at a low temperature of 120-200°C to obtain a high-salt-resistant (TDS content ≤ 60000 mg / L) ozone catalyst; drying can be carried out, for example, in a muffle furnace. Preferably, in step 3), drying is carried out at 120-150°C. Compared to drying at higher temperatures, this results in a coating with better mechanical stability and improves the stability of the structured catalyst, leading to efficient and stable COD removal rates when used to treat organic wastewater. In step 3), the carrier coated with the coating solution is dried until the catalyst reaches a constant weight and its mass no longer decreases (for example, this can be determined by weighing every 1 hour after 6 hours).

[0049] The ozone catalyst prepared using the method of this invention does not require a relatively high coating rate and can achieve good treatment results in treating organic wastewater, obtaining a high COD removal rate and saving costs. In some embodiments, the weight percentage of the coating layer is 2%-10% based on the total weight of the ozone catalyst, preferably 3%-5%. Using the preferred coating amount not only helps to save costs but also improves the COD removal effect of the obtained ozone catalyst on organic wastewater. The inventors have found that if the coating amount is too high, it will lead to a decrease in the COD removal effect.

[0050] In a preferred embodiment, in the coating solution of step 2), the mass ratio of water, silica sol, and manganese dioxide is 50-150:20-30:100, wherein the amount of silica sol is based on the silica content in the silica sol; in step 3), the drying is carried out at 120-150°C; and based on the total weight of the ozone catalyst, the weight percentage of the coating layer is 3%-5%. The catalyst prepared using this preferred combination of conditions exhibits better mechanical properties and superior catalyst activity, resulting in better COD removal efficiency when used for organic wastewater treatment.

[0051] In a preferred embodiment, the porous cordierite is honeycomb cordierite, which has regular honeycomb-shaped channels that can achieve fixed spatial distribution and transport of liquids and gases, reducing the scouring and collision of the catalyst by the fluid. At the same time, the abundant channel structure provides more active sites for the catalytic reaction, which is beneficial for the ozone-catalyzed decomposition of COD.

[0052] In a preferred embodiment, the carrier used in this invention has a regular, well-formed shape, i.e., a carrier with a regular structure, such as a cuboid, cube, or approximately cuboid or approximately cube shape. When an ozone catalyst made with a carrier with a regular structure is used for organic wastewater treatment, it is beneficial to have a more uniform gas-liquid distribution, thereby improving the catalytic reaction efficiency. Moreover, during use, it can reduce collisions caused by catalyst displacement, thereby further reducing catalyst mechanical loss.

[0053] This invention also provides an ozone catalyst, which can be obtained by the preparation method described above. The ozone catalyst includes a support and a coating layer formed on the support, wherein the support is porous cordierite, preferably honeycomb cordierite. The coating layer includes manganese dioxide and silicon dioxide. Preferably, the mass ratio of manganese dioxide to silicon dioxide in the coating layer is 100:12.5 to 100:37.5, which can be obtained based on using a coating solution containing manganese dioxide and silica sol (calculated as silicon dioxide) in a mass ratio of 100:12.5 to 100:37.5 during catalyst preparation. Preferably, the support has a regularly shaped form. Preferably, based on the total weight of the ozone catalyst, the weight percentage of the coating layer is 2%-10%, preferably 3%-5%. This ozone catalyst has a simple composition, requires only a small amount of coating layer to achieve good wastewater treatment results, has high catalytic efficiency, good mechanical stability, and low preparation cost. For a description of ozone catalysts, please refer to the previous explanations; they will not be repeated here.

[0054] The present invention also provides the ozone catalyst obtained by the preparation method described above or the ozone catalyst described above for use in the treatment of organic wastewater, especially for the treatment of organic wastewater generated in the coal chemical industry, specifically for example, high-salt organic wastewater in the coal chemical industry (e.g., high-salt organic wastewater with a salt content TDS≤60000mg / L).

[0055] The present invention will be illustrated below with reference to embodiments:

[0056] The organic wastewater involved in the following examples or comparative examples is high-salt organic wastewater from coal chemical industry, and its various indicators are as follows:

[0057]

[0058] In the following examples, the weight percentage of the coating layer in the obtained catalyst is calculated as follows: the weight of the carrier before coating with the coating liquid is recorded as m1, and the weight after coating with the coating liquid and drying is recorded as m2. The weight ratio of the coating layer is (m2-m1) / m2*100%.

[0059] In the following examples and comparative examples, all raw materials used were commercially available.

[0060] Example 1

[0061] 1) Commercially available honeycomb cordierite was cut into regular structures with length × width × height = 40mm × 40mm × 80mm as a carrier. It was pretreated by soaking it in a sodium hydroxide aqueous solution with pH 12 and water bath at 80℃ for 6 hours, and then washed and dried.

[0062] 2) Prepare a coating solution by mixing 100g MnO2, 100mL silica sol (containing 25g silica), and 100g water; place the coating solution in a ball mill jar and ball mill at 3500r / min for 30min; immerse the pretreated carrier in the above coating solution and repeat the immersion operation multiple times until the surface of the carrier is uniformly coated with a layer of coating solution; then blow it clean to remove excess coating solution.

[0063] 3) The support was dried in an oven at 120°C for 6 hours to obtain catalyst A. See the image of the catalyst. Figure 2 As shown, the coating layer of the obtained catalyst did not exhibit peeling, powdering, or flaking. In catalyst A, the coating layer constituted 5% by weight.

[0064] Performance evaluation of catalyst A in treating organic wastewater:

[0065] The obtained catalyst A was in Figure 1 Organic wastewater was treated using the catalytic ozonation experimental apparatus shown. Ozone generator 1 was turned on and preheated for 30 minutes. Two catalyst pieces 4 (approximately 95g each) were placed in glass reactor 3, and 250mL of organic wastewater sample was added. After adsorption for 1 hour, ozone was introduced into the reactor through a pipeline from the ozone outlet of the ozone generator (gas flow rate: 0.2L / min, inlet ozone concentration: 40mg / L). The ozone gas generated by the ozone generator flowed through a pipeline equipped with a flow meter into the reactor. It formed fine bubbles at the bottom of the reactor via a porous gas distribution plate, contacting catalyst A and the organic wastewater, thus initiating a gas-liquid-solid three-phase reaction. The reaction time was 2 hours. The chemical oxygen demand (COD) in the water was measured using a Hach analyzer. The final result showed that the COD removal rate of the organic wastewater after treatment with catalyst A was 55%. During application, the catalyst coating did not peel off, indicating that the catalyst can be reused.

[0066] In addition, a 200-hour continuous evaluation experiment was conducted on catalyst A. Figure 1 Organic wastewater was continuously passed through the catalytic ozonation experimental apparatus shown. Samples were taken every 2 hours to monitor the COD removal rate, which was found to be between 50% and 55%. The mass of the catalyst before and after the reaction was weighed, and the catalyst loss rate was calculated to be 0.05%.

[0067] Example 2

[0068] 1) Commercially available honeycomb cordierite was cut into regular structures with length × width × height = 40mm × 40mm × 80mm as a carrier. It was pretreated by soaking it in a sodium hydroxide aqueous solution with pH 12 and water bath at 80℃ for 6 hours, and then washed and dried.

[0069] 2) Prepare a coating solution by mixing 100g MnO2, 50mL silica sol (containing 12.5g silica), and 150g water; place the coating solution in a ball mill jar and ball mill at 3500r / min for 30min; immerse the pretreated carrier in the above coating solution and repeat the immersion operation multiple times until the surface of the carrier is uniformly coated with a layer of coating solution; then blow it clean to remove excess coating solution.

[0070] 3) The support was dried in an oven at 120℃ for 6 hours to obtain catalyst B. The coating layer of the obtained catalyst did not exhibit peeling, powdering, or flaking. The coating layer accounted for 3% of the weight of catalyst B.

[0071] The performance evaluation process in Example 1 was used to evaluate the effect of catalyst B on organic wastewater. The results showed that after 2 hours of treatment with catalyst B, the COD removal rate of organic wastewater was 43%. During the application process, the surface coating did not peel off, and the catalyst could be reused.

[0072] Example 3

[0073] 1) Commercially available honeycomb cordierite was cut into regular structures with length × width × height = 40mm × 40mm × 80mm as a carrier. It was pretreated by soaking it in a sodium hydroxide aqueous solution with pH 12 and water bath at 80℃ for 6 hours, and then washed and dried.

[0074] 2) Prepare a coating solution by mixing 100g MnO2, 150mL silica sol (containing 37.5g silica), and 50g water; place the coating solution in a ball mill jar and ball mill at 3500r / min for 30min; immerse the pretreated carrier in the above coating solution and repeat the immersion operation multiple times until the surface of the carrier is uniformly coated with the coating solution; then remove the excess coating solution.

[0075] 3) The support was dried in an oven at 120°C for 6 hours to obtain catalyst C. The coating layer accounted for 10% by weight. The coating layer of the obtained catalyst did not exhibit peeling, powdering, or flaking.

[0076] The performance evaluation process in Example 1 was used to evaluate the effect of catalyst C on organic wastewater. The results showed that after 2 hours of treatment with catalyst C, the COD removal rate of organic wastewater was 50%. During the application process, the coating layer on the catalyst surface did not peel off, and the catalyst can be reused.

[0077] Example 4

[0078] 1) Commercially available honeycomb cordierite was cut into regular structures with length × width × height = 40mm × 40mm × 80mm as a carrier. It was pretreated by soaking it in a sodium hydroxide aqueous solution with pH 12 and water bath at 80℃ for 6 hours, and then washed and dried.

[0079] 2) Prepare a coating solution by mixing 100g MnO2, 100mL silica sol (containing 25g silica), and 100g water; place the coating solution in a ball mill jar and ball mill at 3500r / min for 30min; immerse the pretreated carrier in the above coating solution and repeat the immersion operation multiple times until the surface of the carrier is uniformly coated with a layer of coating solution; then remove the excess coating solution.

[0080] 3) The support was dried in an oven at 200°C for 6 hours to obtain catalyst D. The coating layer in catalyst D accounted for 5% by weight, and the catalyst exhibited slight peeling and powdering.

[0081] The performance evaluation process in Example 1 was used to evaluate the effect of catalyst D on organic wastewater. The results showed that after 2 hours of treatment with catalyst D, the COD removal rate of organic wastewater was 45%. During the application process, slight peeling of the surface coating occurred.

[0082] The main difference between Example 4 and Example 1 is that the drying temperature was increased to 200°C. The resulting catalyst activity was weaker than that of Example 1, and the COD removal rate decreased under the same experimental conditions.

[0083] Comparative Example 1 (compared to Example 1)

[0084] 1) Commercially available honeycomb cordierite was cut into regular structures with length × width × height = 40mm × 40mm × 80mm as a carrier. It was pretreated by soaking it in a sodium hydroxide aqueous solution with pH 12 and water bath at 80℃ for 6 hours, and then washed and dried.

[0085] 2) Prepare a coating solution by mixing 100g MnO2, 100mL silica sol (containing 25g silica), and 100g water; place the coating solution in a ball mill jar and ball mill at 3500r / min for 30min; immerse the pretreated carrier in the above coating solution and repeat the immersion operation multiple times until the surface of the carrier is uniformly coated with a layer of coating solution; then remove the excess coating solution.

[0086] 3) The support was dried in an oven at 280°C for 6 hours to obtain catalyst E; the coating layer in catalyst E accounted for 5% by weight; the coating layer of the obtained catalyst showed obvious pulverization.

[0087] The effect of catalyst E on the treatment of organic wastewater for 2 hours was evaluated according to the performance evaluation process in Example 1. The results showed that the COD removal rate of organic wastewater after 2 hours of treatment with catalyst E was 33%. During the application process, the coating layer of the catalyst showed obvious peeling and could not be reused.

[0088] The main difference between this comparative example and Example 1 is that the drying temperature was increased to 280°C. As a result, the performance of the catalyst was significantly worse, and the COD removal effect was significantly less than that of Example 1.

[0089] Comparative Example 2 (compared to Example 2, without pretreatment)

[0090] 1) Commercially available honeycomb cordierite is cut into regular structures with a length × width × height of 40mm × 40mm × 80mm as the carrier, and then washed and dried with deionized water;

[0091] 2) Prepare a coating solution by mixing 100g MnO2, 50mL silica sol (containing 12.5g silica), and 150g water; place the coating solution in a ball mill jar and ball mill at 3500r / min for 30min; immerse the pretreated carrier in the above coating solution and repeat the immersion operation multiple times until the surface of the carrier is uniformly coated with a layer of coating solution; then remove the excess coating solution.

[0092] 3) The support was dried in an oven at 120°C for 6 hours to obtain catalyst F. The coating layer in catalyst F has a weight percentage of 1.3%.

[0093] The performance evaluation process in Example 1 was used to evaluate the effect of catalyst F on organic wastewater. The results showed that after 2 hours of treatment with catalyst F, the COD removal rate of organic wastewater was 27%.

[0094] Compared with Example 2, the main difference in this comparative example is that the support was not pretreated with an alkaline solution. As a result, the coating liquid was difficult to fully coat and adhere to the support, and the coating amount was difficult to reach more than 2%. The activity of the resulting catalyst was significantly worse, and the COD removal effect was significantly worse than that of Example 2.

[0095] Comparative Example 3 (compared to Example 1)

[0096] 1) Commercially available honeycomb cordierite was cut into regular structures with length × width × height = 40mm × 40mm × 80mm as a carrier. It was pretreated by soaking it in a sodium hydroxide aqueous solution with pH 12 and water bath at 80℃ for 6 hours, and then washed and dried.

[0097] 2) Prepare a coating solution by mixing 100g MnO2, 100mL aluminum sol (alumina content is 25g) and 100g water; place the coating solution in a ball mill jar and ball mill at 3500r / min for 30min; immerse the pretreated carrier in the above coating solution and repeat the immersion operation multiple times until the surface of the carrier is uniformly coated with a layer of coating solution; then remove the excess coating solution.

[0098] 3) The support was dried in an oven at 120°C for 6 hours to obtain catalyst G. The coating layer in catalyst G accounted for 5% by weight. During the experiment, it was found that the coating layer in this comparative example exhibited obvious powdering on the support surface and was easily detached, indicating that the coating solution could not form on the support surface.

[0099] The performance evaluation process in Example 1 was used to evaluate the effect of catalyst G on organic wastewater. The results showed that after 2 hours of treatment with catalyst G, the COD removal rate of the organic wastewater was 30% (the surface coating detached into the solution, making it difficult to recover and reuse). Compared with Example 1, the main difference in this comparative example is that silica sol was replaced with aluminum sol. As a result, the mechanical properties and catalytic activity of the catalyst were significantly worse, and the COD removal rate was significantly reduced.

[0100] As can be seen from the above experiments, the ozone catalyst obtained by the method of the present invention has better catalytic activity, better COD removal effect, and good mechanical properties. The coating layer is not easily pulverized and / or peeled off, or there is no obvious pulverization and / or peeling phenomenon. Even under relatively low coating amount conditions, a good COD removal effect can still be obtained. In Example 1, by using the preferred coating solution composition, preferred drying conditions, and preferred coating amount, the resulting catalyst has even better performance and a better COD removal effect.

[0101] For Examples 2-4, similar continuous evaluation tests as for Example 1 were conducted. Examples 2-3 had essentially the same COD removal rate stability (COD removal rate fluctuation of about 5%) and catalyst loss rate (COD removal rate of about 0.05%) as Example 1. However, the COD removal rate stability and catalyst loss rate of Example 4 were worse than those of Examples 1-3.

[0102] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. Use of an ozone catalyst, characterized in that, The ozone catalyst is applied in the treatment of organic wastewater generated in the field of coal chemical industry, and the preparation method of the ozone catalyst comprises the following steps: 1) taking porous cordierite as a carrier, pretreating the carrier in an alkaline solution, and then cleaning and drying; 2) coating a coating liquid on the carrier pretreated in step 1); the coating liquid comprises manganese dioxide and silica sol; in the coating liquid, the mass ratio of water, silica sol and manganese dioxide is 50-150:20-37.5:100, wherein the amount of silica sol is calculated based on the content of silicon dioxide in the silica sol; 3) drying the carrier coated with the coating liquid in step 2) at 120-150 ℃ to obtain an ozone catalyst with a coating layer formed on the carrier.

2. Use according to claim 1, characterized in that, In step 1), the pH of the alkaline solution is 10-12.

3. Use according to claim 2, characterized in that, In step 1), the pretreatment is carried out at 60-100 ℃.

4. Use according to claim 3, characterized in that, In step 1), the pretreatment time is 6-10 h.

5. Use according to claim 2, characterized in that, The alkaline solution is selected from an aqueous solution of sodium hydroxide and / or potassium hydroxide.

6. Use according to any one of claims 1 to 5, characterized in that, In step 2), the carrier pretreated in step 1) is repeatedly soaked in the coating liquid for multiple times to coat the coating liquid on the carrier.

7. The use according to any one of claims 1 to 5, characterized in that, The weight percentage of the coating layer is 2%-10% based on the total weight of the ozone catalyst.

8. Use according to claim 7, characterized in that, The weight percentage of the coating layer is 3%-5% based on the total weight of the ozone catalyst.

9. Use according to any one of claims 1 to 5, characterized in that, In the coating liquid of step 2), the mass ratio of water, silica sol and manganese dioxide is 50-150:20-30:100, wherein the amount of silica sol is calculated based on the content of silicon dioxide in the silica sol; In step 3), the drying is carried out at 120-150 ℃; The weight percentage of the coating layer is 3%-5% based on the total weight of the ozone catalyst.

10. Use according to any one of claims 1 to 5, characterized in that, The porous cordierite is honeycomb-shaped cordierite; And / or, the carrier has a regular shaped appearance.

11. Use according to any one of claims 1 to 5, characterized in that, The ozone catalyst takes porous cordierite as a carrier, and a coating layer is formed on the carrier, wherein the coating layer comprises manganese dioxide and silicon dioxide.

12. Use according to claim 11, characterized in that, The weight percentage of the coating layer is 3-5% based on the total weight of the ozone catalyst.

13. The use according to claim 11, characterized in that, In the coating layer, the mass ratio of the manganese dioxide and the silicon dioxide is 100:12.5-100:37.

5.

14. The use according to claim 11, characterized in that, The porous cordierite is honeycomb-shaped cordierite; And / or, the carrier has a regular shaped appearance.

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