Sludge-based high-entropy oxide catalyst and preparation method thereof

Abstract

The invention belongs to the field of environmental engineering water treatment, and particularly discloses a sludge-based high-entropy oxide catalyst and a preparation method thereof.The catalyst is composed of a sludge carrier and a high-entropy oxide according to the mass ratio of 20-400: 1, and the preparation method of the catalyst specifically comprises the steps that S1, the sludge carrier is cleaned and then dried for use; s2, activating the standby carrier material; s3, doping a high-entropy oxide into the activated carrier material; s4, performing high-temperature sintering on the material obtained in S3; the sludge-based high-entropy oxide catalyst has high catalytic activity, can effectively improve the utilization efficiency of ozone (Fenton catalysis), and reduces the aeration rate and the operation cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment materials, and particularly relates to a sludge-based high-entropy oxide catalyst and a preparation method thereof. Background Art

[0002] With the rapid development of industrialization, the discharge of industrial wastewater has been increasing continuously. A large number of toxic and harmful organic pollutants contained therein pose a serious threat to the environment and human health. In recent years, new pollutants, especially perfluorinated compounds, have grown rapidly in variety and attracted global attention due to their characteristics such as biotoxicity, environmental persistence, and bioaccumulation. In the field of advanced treatment of industrial wastewater PFAS, advanced oxidation processes (AOPs) are considered to be one of the representative technologies to achieve this goal. Among them, the ozone catalytic oxidation technology has received extensive attention in recent years due to its high treatment efficiency, wide application range, and ability to effectively remove refractory organic pollutants and toxic and harmful substances. Its reaction process mainly adsorbs ozone molecules through the active sites on the catalyst surface and decomposes them into more oxidizing active free radicals such as hydroxyl radicals or superoxide radicals (such as ·OH, ·O2 - 、 1 O2, etc.), and reacts with the organic pollutants adsorbed on the catalyst surface or in the water body to oxidize them into low-toxicity or non-toxic small-molecule substances, or even mineralize them into carbon dioxide and water. In addition, Fenton catalysis can catalyze the chain reaction between divalent iron ions (Fe 2+ ) and hydrogen peroxide to generate hydroxyl radicals, which have strong oxidation ability. Hydroxyl radicals have high electronegativity or electrophilicity, so the Fenton reaction has a high ability to remove refractory organic pollutants and is widely used in the treatment of wastewater such as printing and dyeing wastewater, oily wastewater, phenolic wastewater, coking wastewater, nitrobenzene-containing wastewater, and diphenylamine wastewater. The key to the ozone catalytic oxidation and Fenton catalytic processes is an efficient catalyst. At present, ozone (Fenton) catalysts mainly include single-metal or multi-metal oxides, carbon-based non-metals, etc. However, considering factors such as cost-effectiveness, environmental protection, and high performance, cheap and green environmentally friendly catalysts are urgently needed to be explored.

[0003] As a green and environmentally friendly new functional material, biochar materials have great application potential in the field of wastewater ozone catalysis (Fenton catalysis) due to their excellent physical and chemical properties and diverse surface functionalities. However, most biochar-derived catalysts are prepared by doping metals or metal oxides with biochar as the matrix, often suffering from problems such as cumbersome steps, low activity, and high costs. Therefore, developing an easily prepared and highly active biochar-based catalytic material is of great significance for achieving efficient ozone catalysis. As a precursor of biochar, sludge is deposited at the bottom of water bodies after long-term physical, chemical, biological actions and water body transportation. It is composed of clay, sediment, organic matter, and various minerals and can be used as a good raw material for preparing biochar. At the same time, due to its rich organic groups and resource substances such as C, N, and P, it can serve as surface active sites and adsorption sites. In addition, the sludge powder has excellent hardness and strength after granulation, which can meet the requirements of aeration during the ozone catalysis process. It can not only turn waste into treasure and increase the added value of sludge but also improve the resource utilization efficiency of sludge.

[0004] Due to their characteristics such as rich active sites and electronic structures, high entropy oxides (HEOs) show broad application prospects in the field of ozone catalysis (Fenton catalysis). Usually, methods for synthesizing high entropy oxides include ball milling, etc., but this may lead to sintering of powder particles and easy agglomeration, limiting the formation of nanoparticles. In addition, single high entropy oxides often face problems such as phase separation and agglomeration in industrial wastewater, resulting in a decrease in the activity and stability of high entropy oxides. Therefore, loading high entropy oxides prepared by the co-precipitation method on a sludge-based carrier is an effective strategy, which can not only improve the conductivity and dispersibility of high entropy oxides in solution but also enhance their degradation activity and stability. At the same time, the sludge-based carrier exposes rich surface active sites to optimize the adsorption energy of reaction intermediate species, thereby effectively improving the degradation efficiency and selectivity and promoting their development and application in the catalytic field. Patent [202411216161.4] uses a solution method to coat lithium titanate and amorphous carbon on the surface of high entropy oxides to achieve uniform doping of titanium elements in the bulk phase, showing excellent structural stability and applying it to the lithium insertion / extraction reaction. Patent [202010768018.1] discloses a method for preparing a persulfate catalyst using coagulation sludge from a water treatment plant and applying it to the degradation of Rhodamine B. However, there are few reports on the theoretical and application research of ozone catalysis (Fenton catalysis) using sludge and its derived carbon catalytic materials. In addition, promoting the production of HEOs catalysts to engineering applications and achieving ozone catalytic oxidation (Fenton catalysis) under complex conditions also faces challenges. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a sludge-based high-entropy oxide catalyst and a preparation method thereof, which can convert waste sludge into a sludge-derived catalyst material with high added value for water treatment, break through the bottleneck of the current sludge treatment method, and expand a new mode of sludge resource utilization through the method of this patent to achieve high-value resource utilization of sludge.

[0006] The technical solution of the present invention to solve the above technical problems is: a sludge-based high-entropy oxide catalyst, which is composed of a sludge carrier and a high-entropy oxide, and the mass ratio thereof is 20 - 400:1.

[0007] The present invention provides a preparation method of a sludge-based high-entropy oxide catalyst, which specifically includes the following steps:

[0008] S1 Wash the sludge carrier with ultrapure water, then place it in an oven for drying treatment, and set it aside for use.

[0009] S2 Activate the reserved carrier material.

[0010] S3 Dope high-entropy oxide into the carrier material after activation treatment. Specifically, dissolve a metal precursor solution with an equimolar ratio in N,N-dimethylformamide to obtain solution A with a concentration of 1 g / L - 100 g / L, dissolve terephthalic acid in N,N-dimethylformamide to obtain solution B with a concentration of 50 g / L - 200 g / L, then mix the above two solutions A and B, add triethanolamine and stir. The mass ratio of triethanolamine to terephthalic acid is 1:(0.1 - 0.5). Finally, mix it with the carrier material and stir evenly, and place it in an oven for drying to obtain a precursor.

[0011] S4 Place the dried material obtained in S3 in a muffle furnace for high-temperature sintering, and sinter the sludge-based high-entropy oxide in the precursor to the surface layer of the carrier.

[0012] Preferably, in S1, after washing the sludge carrier with ultrapure water, place it in an oven for drying treatment and set it aside for use, and the oven temperature is 80 - 85 °C.

[0013] Preferably, in S2, activate the reserved carrier material, prepare a 30 - 50 mmol / L H2O2 solution, place the carrier material and the oxidant in a hydrothermal autoclave, and react at 70 - 85 °C for 3 - 5 h.

[0014] Preferably, in S3, the metal precursor solution is an aqueous solution of metal salts, and the metal elements are any 5 or more combinations of iron, cobalt, nickel, copper, manganese, cerium, aluminum, magnesium, chromium, titanium, tin, molybdenum, and zinc.

[0015] Preferably, the metal salt can be a metal organic salt or a metal inorganic salt, and the metal inorganic salt is any one or a combination of at least two of metal acetates, metal chlorides, and metal nitrates.

[0016] Preferably, in S4, the dried material obtained in S3 is placed in a muffle furnace for high-temperature sintering, heated at a rate of 8 - 10 °C / min, and calcined at a temperature of 400 - 800 °C for 2 - 3 h.

[0017] The beneficial effects of the present invention are as follows:

[0018] (1) The present invention designs a method for converting sludge into a high-value catalyst for water treatment, using the organic groups and resource substances such as C, N, and P rich in sludge as surface active sites and adsorption sites. In addition, after high-temperature pyrolysis, the sludge also has excellent hardness and strength, which can meet the requirements of aeration in ozone catalysis and Fenton processes. Compared with the traditional incineration method, this innovation opens up a new path for the disposal of waste sludge and promotes the formation of a more sustainable new model for the resource utilization of wastewater and waste.

[0019] (2) The catalytic material of the present invention is prepared by a co-precipitation - high-temperature calcination process. Compared with the traditional ball milling method and solid-phase synthesis method, it has a lower synthesis and sintering temperature, can obtain materials with small particle size and uniform mixing, and has a low industrial production cost. At the same time, the adsorption characteristics and multi-active site catalytic characteristics of sludge and high-entropy oxides can be exerted and effectively combined. The adsorption, degradation, and catalytic properties of the composite material are all greater than those of single sludge or single high-entropy oxide, which not only promotes the degradation of pollutants in industrial wastewater but also effectively improves the removal rate of conventional indicators such as COD and the utilization rate of medicaments.

[0020] (3) After activation, the catalytic material of the present invention can increase the amount of oxygen-containing functional groups on the surface of the carrier, enhance the binding ability to the active metal in the precursor, is conducive to increasing the reaction sites of the filler, and improving the catalytic performance of the material; and the re-activated catalyst can adsorb and complex metal ions in the solution, increasing the reaction active sites and prolonging the service life of the catalyst.

[0021] (4) The catalyst of the present invention has a porous structure and a large specific surface area, has a good effect on wastewater treatment, reduces the dosage of medicaments, reduces the generation of iron sludge, and lowers energy consumption and operating costs. The conditions are mild, the operation is simple, and there is no other waste discharge, having extremely high economic value and industrial application prospects. Description of the Drawings

[0022] Figure 1 It is the Fourier transform infrared spectrum diagram of the sludge in Example 1 of the present invention;

[0023] Figure 2XRD pattern of the sludge-based high-entropy oxide catalyst of Embodiment 2 of the present invention;

[0024] Figure 3 Electron microscopy spectrum of the sludge-based high-entropy oxide catalyst described in Embodiment 3 of the present invention;

[0025] Figure 4 Electron paramagnetic resonance spectrum of the sludge-based high-entropy oxide catalyst described in Embodiment 4 of the present invention. Detailed implementation manners

[0026] Embodiment 1

[0027] This embodiment provides a sludge-based high-entropy oxide catalyst, which is composed of a sludge carrier and a high-entropy oxide, and their mass ratio is 400:1.

[0028] The preparation method of the above catalyst specifically includes the following steps:

[0029] S1 Wash the sludge carrier with ultrapure water and then place it in an oven at 80°C for drying treatment for later use;

[0030] S2 Activate the prepared carrier material. Prepare a 30 mmol / L H2O2 solution, place the carrier and the oxidant in a hydrothermal autoclave, and react at 80°C for 4 h;

[0031] S3 Dope the high-entropy oxide into the carrier material after activation treatment. Specifically: dissolve the metal salt solution with equimolar ratio in N,N-dimethylformamide to obtain solution A with a concentration of 100 g / L. The above metal precursor solution is a metal chloride solution, and the metal elements are iron, cobalt, nickel, copper, and manganese;

[0032] Dissolve terephthalic acid in N,N-dimethylformamide to obtain solution B with a concentration of 200 g / L. Then mix the above two solutions A and B, add triethanolamine and stir. The mass ratio of triethanolamine to terephthalic acid is 1:0.4. Finally, mix it with the carrier and stir for 2 h, and place it in an oven at 80°C for drying to obtain a precursor;

[0033] S4 Place the dried material obtained in S3 in a muffle furnace for high-temperature sintering. Heat it up at a rate of 10°C / min and calcine it at 600°C for 2 h to sinter the sludge-based high-entropy oxide in the precursor to the surface layer of the carrier.

[0034] Fenton catalysis: The biochemical effluent of a certain industrial enterprise has a COD of about 870 mg / L and needs to meet the local sewage network connection standard (COD ≤ 500 mg / L). The prepared catalyst is filled in a Fenton fluidized bed reaction column. An inlet is set at the lower end of the bed layer, and an outlet is set at the upper end. A peristaltic pump is externally connected to the fluidized bed. The wastewater to be treated enters the fluidized bed from the lower inlet and flows out from the upper outlet, thereby circulating and treating the wastewater to be treated. The rotational speed of the peristaltic pump is set at 100 rpm. The catalyst in the Fenton fluidized bed can effectively contact the water body, improve the mass transfer efficiency, and thus enhance the reaction rate. 50 g / L of the catalyst is put into the system, the concentration of hydrogen peroxide is 220 mg / L, and the concentration of FeSO4 is 50 mg / L. The peristaltic pump is started, and the wastewater is degraded by the heterogeneous Fenton reaction.

[0035] Example 2

[0036] This example provides a sludge-based high-entropy oxide catalyst, which is composed of a sludge carrier and a high-entropy oxide, and their mass ratio is 100:1.

[0037] The preparation method of the above catalyst specifically includes the following steps:

[0038] S1 Wash the sludge carrier with ultrapure water, then place it in an oven at 80 °C for drying treatment, and set aside;

[0039] S2 Activate the spare carrier material. Prepare a 30 mmol / L H2O2 solution, place the carrier and the oxidant in a hydrothermal autoclave, and react at 80 °C for 4 h;

[0040] S3 Dope high-entropy oxide into the carrier material after activation treatment. Specifically: dissolve metal salt solutions with equimolar ratios in N,N-dimethylformamide to obtain solution A with a concentration of 100 g / L. The above metal precursor solution is a mixed solution of acetate and chloride, and the metal elements are iron, cobalt, manganese, cerium, and nickel;

[0041] Dissolve terephthalic acid in N,N-dimethylformamide to obtain solution B with a concentration of 200 g / L. Then mix the above two solutions A and B, add triethanolamine and stir. The mass ratio of triethanolamine to terephthalic acid is 1:0.3. Finally, mix it with the carrier and stir for 2 h, and place it in an oven at 80 °C for drying to obtain a precursor;

[0042] S4 Place the dried material obtained in S3 in a muffle furnace for high-temperature sintering. Heat it at a rate of 10 °C / min and calcine it at 600 °C for 2 h to sinter the sludge-based high-entropy oxide in the precursor to the surface layer of the carrier.

[0043] Fenton catalysis: The biochemical effluent of an industrial enterprise has a COD of about 870 mg / L and needs to meet the local sewage network connection standard (COD ≤ 500 mg / L). The catalyst is loaded into a Fenton fluidized bed reactor column. An inlet is provided at the lower end of the bed layer, and an outlet is provided at the upper end. A peristaltic pump is externally connected to the fluidized bed. The wastewater to be treated enters the fluidized bed from the lower inlet and flows out from the upper outlet, thereby circulating and treating the wastewater to be treated. The rotational speed of the peristaltic pump is set to 100 rpm. The catalyst in the Fenton fluidized bed can effectively contact the water body, improve the mass transfer efficiency, and thus enhance the reaction rate. 50 g / L of the catalyst is added to the system, the hydrogen peroxide concentration is 220 mg / L, and the FeSO4 concentration is 50 mg / L. The peristaltic pump is turned on, and the wastewater is degraded by the heterogeneous Fenton reaction.

[0044] Example 3

[0045] This example provides a sludge-based high-entropy oxide catalyst, which is composed of a sludge carrier and a high-entropy oxide, and their mass ratio is 100:1.

[0046] The preparation method of the above catalyst specifically includes the following steps:

[0047] S1: After washing the sludge carrier with ultrapure water, it is placed in an oven at 80 °C for drying treatment and reserved;

[0048] S2: The reserved carrier material is activated. A 30 mmol / L H2O2 solution is prepared. The carrier and the oxidant are placed in a hydrothermal autoclave and reacted at 80 °C for 4 h;

[0049] S3: The activated carrier material is doped with a high-entropy oxide. Specifically: equimolar metal salt solutions are dissolved in N,N-dimethylformamide to obtain solution A with a concentration of 100 g / L. The above metal precursor solution is a mixed solution of metal chloride and metal nitrate, and the metal elements are iron, chromium, titanium, tin, and molybdenum;

[0050] Terephthalic acid is dissolved in N,N-dimethylformamide to obtain solution B with a concentration of 200 g / L. Then the above two solutions A and B are mixed, and triethanolamine is added and stirred. The mass ratio of triethanolamine to terephthalic acid is 1:0.4. Finally, it is mixed and stirred with the carrier for 2 h and placed in an oven at 80 °C for drying to obtain a precursor;

[0051] S4: The dried material obtained in S3 is placed in a muffle furnace for high-temperature sintering. It is heated at a rate of 10 °C / min and calcined at 600 °C for 2 h to sinter the sludge-based high-entropy oxide in the precursor to the surface layer of the carrier.

[0052] Ozone Catalysis: For a certain industrial enterprise, the biochemical effluent has a COD of approximately 870 mg / L and needs to meet the local sewage network connection standard (COD ≤ 500 mg / L). The catalyst is loaded into an ozone catalytic device. The device has an inlet at the lower end and an outlet at the upper end. The device is externally connected to a peristaltic pump. The wastewater to be treated enters the device from the lower inlet and flows out from the upper outlet, thereby circulating and treating the wastewater to be treated. The rotation speed of the peristaltic pump is set at 100 rpm. The catalyst in the ozone catalytic device can effectively contact the water body, improve the mass transfer efficiency, and thus enhance the reaction rate. 150 g / L of the catalyst is added to the system, and the ozone aeration rate is 300 mg / L. The peristaltic pump is turned on, and the wastewater is degraded by the ozone catalytic oxidation reaction.

[0053] Example 4

[0054] This example provides a sludge-based high-entropy oxide catalyst, which consists of a sludge carrier and a high-entropy oxide, and their mass ratio is 20:1.

[0055] The preparation method of the above catalyst specifically includes the following steps:

[0056] S1 Wash the sludge carrier with ultrapure water and then place it in an 80 °C oven for drying treatment for later use;

[0057] S2 Activate the prepared carrier material. Prepare a 30 mmol / L H2O2 solution, place the carrier and the oxidant in a hydrothermal autoclave, and react at 80 °C for 4 h;

[0058] S3 Dope the high-entropy oxide into the carrier material after activation treatment. Specifically: dissolve the metal salt solution with an equimolar ratio in N,N-dimethylformamide to obtain solution A with a concentration of 100 g / L. The above metal precursor solution is a mixed solution of metal acetate, metal chloride, and metal nitrate, and the metal elements are manganese, cerium, aluminum, magnesium, and chromium;

[0059] Dissolve terephthalic acid in N,N-dimethylformamide to obtain solution B with a concentration of 200 g / L. Then mix the above two solutions A and B, add triethanolamine and stir. The mass ratio of triethanolamine to terephthalic acid is 1:0.3. Finally, mix it with the carrier and stir for 2 h, and place it in an oven at 80 °C for drying to obtain the precursor;

[0060] S4 Place the dried material obtained in S3 in a muffle furnace for high-temperature sintering. Heat it at a rate of 10 °C / min and calcine it at 600 °C for 2 h to sinter the sludge-based high-entropy oxide in the precursor to the surface layer of the carrier.

[0061] Ozone catalysis: For a certain industrial enterprise, the biochemical effluent has a COD of approximately 870 mg / L and needs to meet the local sewage network connection standard (COD ≤ 500 mg / L). The catalyst is loaded into an ozone catalytic device. The device has an inlet at the lower end and an outlet at the upper end. The device is externally connected to a peristaltic pump. The wastewater to be treated enters the device from the lower inlet and flows out from the upper outlet, thereby circulating the wastewater to be treated. The rotational speed of the peristaltic pump is set at 100 rpm. The catalyst in the ozone catalytic device can effectively contact the water body, improve the mass transfer efficiency, and thus enhance the reaction rate. 150 g / L of the catalyst is added to the system, and the ozone aeration volume is 300 mg / L. The peristaltic pump is turned on, and the wastewater is degraded by the ozone catalytic oxidation reaction.

[0062] Comparative Example 1

[0063] A sludge-based high-entropy oxide catalytic material, which is composed of a sludge carrier and a high-entropy oxide with a mass ratio of 20:1. Its preparation method includes the following steps:

[0064] Wash the sludge carrier with ultrapure water and then place it in an 80 °C oven for drying treatment;

[0065] Activate the spare carrier material. Prepare a 30 mmol / L H2O2 solution, place the carrier and the oxidant in a hydrothermal autoclave, and react at 80 °C for 4 h;

[0066] The high-entropy oxide is doped into the sludge carrier. Specifically, it is prepared by the ball milling method. Weigh a certain amount of Fe2O3 (0.808 g), NiO (0.833 g), Cr2O3 (0.768 g), MnO2 (0.966 g), and Co3O4 (0.803 g). After stirring evenly, add them to the ball milling tank, and then add an appropriate amount of grinding balls and alcohol, and grind at a speed of 300 revolutions per minute for 3 hours. The precursor is dried in an oven at 70 °C and then heat-treated.

[0067] Ozone catalysis: For a certain industrial enterprise, the biochemical effluent has a COD of approximately 870 mg / L and needs to meet the local sewage network connection standard (COD ≤ 500 mg / L). The catalyst is loaded into an ozone catalytic device. The device has an inlet at the lower end and an outlet at the upper end. The device is externally connected to a peristaltic pump. The wastewater to be treated enters the device from the lower inlet and flows out from the upper outlet, thereby circulating the wastewater to be treated. The rotational speed of the peristaltic pump is set at 100 rpm. The catalyst in the ozone catalytic device can effectively contact the water body, improve the mass transfer efficiency, and thus enhance the reaction rate. 150 g / L of the catalyst is added to the system, and the ozone aeration volume is 300 mg / L. The peristaltic pump is turned on, and the wastewater is degraded by the ozone catalytic oxidation reaction.

[0068] Comparative Example 2

[0069] This comparative example provides a sludge catalyst, which is composed of a single sludge.

[0070] The preparation method of the above catalyst specifically includes the following steps:

[0071] S1 Wash the sludge with ultrapure water, then place it in an oven at 80 °C for drying treatment, and set aside;

[0072] S2 Activate the reserved material, prepare a 30 mmol / L H2O2 solution, place the material and the oxidant in a hydrothermal kettle, and react at 80 °C for 4 h;

[0073] S3 Place the material obtained after activation treatment in step S2 in a muffle furnace for high-temperature sintering, heat it up at a rate of 10 °C / min, and calcine it at 600 °C for 2 h.

[0074] Ozone catalysis: The biochemical effluent of a certain industrial enterprise has a COD of about 870 mg / L and needs to meet the local sewage network connection standard (COD ≤ 500 mg / L). Load the catalyst into an ozone catalytic device. An inlet is provided at the lower end of the device, and an outlet is provided at the upper end. A peristaltic pump is externally connected to the device. The wastewater to be treated enters the device from the lower inlet and flows out from the upper outlet, so as to circulate the wastewater to be treated. Set the rotation speed of the peristaltic pump to 100 rpm. The catalyst in the ozone catalytic device can effectively contact the water body, improve the mass transfer efficiency, and thus increase the reaction rate. Put 150 g / L of catalyst into the system, the ozone aeration volume is 300 mg / L, turn on the peristaltic pump, and use the ozone catalytic oxidation reaction to degrade the wastewater.

[0075] Comparative Example 3

[0076] This comparative example provides a high-entropy oxide catalyst, which is composed of a single high-entropy oxide.

[0077] The preparation method of the above catalyst specifically includes the following steps:

[0078] S1 Dissolve the metal salt solution with an equimolar ratio in N,N-dimethylformamide to obtain solution A with a concentration of 100 g / L. The above metal precursor solution is a mixed solution of metal acetate, metal chloride, and metal nitrate, and the metal elements are manganese, cerium, aluminum, magnesium, and chromium;

[0079] S2 Dissolve terephthalic acid in N,N-dimethylformamide to obtain solution B with a concentration of 200 g / L. Then mix the above two solutions A and B, add triethanolamine and stir. The mass ratio of triethanolamine to terephthalic acid is 1:0.3. Mix and stir for 2 h, and place it in an oven at 80 °C for drying to obtain a precursor;

[0080] S3 Place the dried material obtained in S2 in a muffle furnace for high-temperature sintering, heating at a rate of 10 °C / min and calcining at 600 °C for 2 h.

[0081] Ozone catalysis: The biochemical effluent of an industrial enterprise has a COD of about 870 mg / L and needs to meet the local sewage network connection standard (COD ≤ 500 mg / L). Load the catalyst into the ozone catalytic device. The lower end of the device is provided with an inlet, and the upper end is provided with an outlet. The device is externally connected to a peristaltic pump. The wastewater to be treated enters the device from the lower inlet and flows out from the upper outlet, so as to circulate the wastewater to be treated. Set the rotation speed of the peristaltic pump to 100 rpm. The catalyst in the ozone catalytic device can effectively contact the water body, improve the mass transfer efficiency, and thus increase the reaction rate. Put 150 g / L of catalyst into the system, with an ozone aeration rate of 300 mg / L. Turn on the peristaltic pump and use the ozone catalytic oxidation reaction to degrade the wastewater.

[0082] Table 1 Comparison of the removal effects of the catalysts in the examples of the present invention / the catalysts in the comparative examples on the biochemical effluent of an industrial enterprise

[0083]

[0084] From the above experimental data, it can be seen that the COD removal rate of the comparative example by ozone oxidation is only 23.3%, and the COD removal rates of single sludge and high-entropy oxides are even lower. After using the catalyst of the present invention, a COD removal rate of more than 46% can be achieved. Figure 1 It is the Fourier infrared spectrum of the sludge material. It can be seen that there are abundant O-H, C=C, C-O and C-H functional groups in the sludge, providing abundant adsorption sites for organic pollutants. Figure 2 It is the X-ray diffraction (XRD) pattern of HEO, showing a single orthorhombic crystal structure. Figure 3 It is the morphology of the material under the SEM at a scale of 100 nm, showing an irregular flaky structure. From the EPR test results (as Figure 4 shown), this material has strong superoxide radicals and hydroxyl radicals, which is beneficial to the mineralization and degradation of organic pollutants.

[0085] In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A sludge-based high-entropy oxide catalyst, characterized in that: The catalyst is composed of a sludge support and a high-entropy oxide, and their mass ratio is 20 - 400:

1.

2. The preparation method of a sludge-based high-entropy oxide catalyst according to claim 1, characterized in that The catalyst is composed of a sludge support and a high-entropy oxide, and their mass ratio is 20 - 400:

1. The specific steps are as follows: S1 Wash the sludge support and then perform a drying treatment for later use. S2 Activate the prepared support material. S3 Dope the high-entropy oxide into the activated support material. Specifically, dissolve the metal precursor solution with equimolar ratio in N,N-dimethylformamide to obtain solution A with a concentration of 1 g / L - 100 g / L, dissolve terephthalic acid in N,N-dimethylformamide to obtain solution B with a concentration of 50 g / L - 200 g / L, then mix the above two solutions A and B, add triethanolamine and stir. The mass ratio of triethanolamine to terephthalic acid is 1:(0.1 - 0.5). Finally, mix it with the support material and stir evenly, and then perform drying to obtain the precursor. S4 High-temperature sinter the dried material obtained in S3, and sinter the sludge-based high-entropy oxide in the precursor to the surface layer of the support.

3. The preparation method of a sludge-based high-entropy oxide catalyst according to claim 2, characterized in that: In S1, after washing the sludge support, perform a drying treatment for later use.

4. The preparation method of a sludge-based high-entropy oxide catalyst according to claim 2, characterized in that: In S2, activate the prepared support material. Prepare an H2O2 solution with a concentration of 30 - 50 mmol / L, place the support material and the oxidant in a hydrothermal reactor, and react at 70 - 85 °C for 3 - 5 h.

5. The preparation method of a sludge-based high-entropy oxide catalyst according to claim 1, characterized in that: In S3, the metal precursor solution is an aqueous solution of metal salts, and the metal elements are any combination of 5 or more of iron, cobalt, nickel, copper, manganese, cerium, aluminum, magnesium, chromium, titanium, tin, molybdenum, and zinc.

6. The preparation method of a sludge-based high-entropy oxide catalyst according to claim 5, characterized in that: The metal salt can be a metal organic salt or a metal inorganic salt, and the metal inorganic salt is any one or at least two combinations of metal acetates, metal chlorides, and metal nitrates.

7. The preparation method of a sludge-based high-entropy oxide catalyst according to claim 1, characterized in that: In S4, high-temperature sinter the dried material obtained in S3, heat it up at a rate of 8 - 10 °C / min, and calcine it at a temperature of 400 - 800 °C for 2 - 3 h.

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