Wet oxidation catalyst, preparation method, organic wastewater treatment method and application

Abstract

The invention discloses a wet oxidation catalyst, a preparation method, an organic wastewater treatment method and application. The wet oxidation catalyst comprises a carrier and an active component, the active component comprises at least one of platinum group elements, and the platinum group elements are derived from nitrate of at least one of the platinum group elements. The treatment method disclosed by the invention is high in removal rate of ammonia nitrogen in the high-concentration ammonia nitrogen wastewater, and the process is simple.

Description

Technical Field

[0001] The present invention relates to the technical field of organic wastewater treatment, and specifically relates to a wet oxidation catalyst, a preparation method, an organic wastewater treatment method and an application thereof. Background Art

[0002] Ammonia nitrogen (N-NH3) is a main pollutant in wastewater. Due to the unique biological toxicity of ammonia nitrogen wastewater, it has a serious inhibitory and toxic effect on microorganisms, and generally biochemical methods cannot be used to treat high-concentration ammonia nitrogen wastewater. As a high-end technology of advanced oxidation technology, catalytic wet air oxidation can oxidize and decompose ammonia nitrogen in sewage into harmless substances such as N2 and H2O through air oxidation at a certain temperature and pressure, achieving the purpose of purification. It has high purification efficiency and small floor area, and is suitable for the treatment of high-concentration ammonia nitrogen wastewater.

[0003] According to the properties of the catalyst, catalytic wet air oxidation technology is divided into homogeneous and heterogeneous catalytic wet air oxidation. Early research mainly focused on homogeneous catalysts. However, since the catalyst dissolves in the wastewater and causes secondary pollution, subsequent treatment is required, which has gradually phased out this method. In recent years, heterogeneous catalysts have become a research hotspot. Heterogeneous catalysts mainly include two categories: noble metals and metal oxides. Among them, most noble metal catalysts use TiO2, Al2O3, SiO2, ZrO2 or their composite oxides as carriers, and noble metal elements such as Ru, Pt, Pd, and Rh are loaded on the above carriers.

[0004] The patents for catalytic wet air oxidation technology are disclosed as follows:

[0005] CN1084496A discloses a wet air oxidation purification catalyst for industrial sewage containing high concentrations of organic matter and ammonia, which is composed of a noble metal component (one of Ru, Rh, Pd, Ir, Pt) and rare earth elements supported on TiO2, and adopts a preparation technique of co-impregnation or separate impregnation of dual active components. CN1121322A discloses a catalyst for wastewater treatment, a manufacturing method thereof, and a wastewater treatment method using the catalyst. The catalyst contains manganese oxides and / or composite oxides and at least one metal oxide and / or composite oxide selected from the group consisting of iron, titanium, and zirconium, and may also contain noble metals when necessary. However, the current catalytic wet air oxidation technology is not used alone to treat high-concentration ammonia nitrogen wastewater, and other wastewater treatment methods are not thorough in treating high-concentration ammonia nitrogen wastewater or have a long process and high energy consumption. Therefore, there is an urgent need for a treatment method with a high ammonia nitrogen removal rate for high-concentration ammonia nitrogen wastewater and a simple process. Summary of the Invention

[0006] To solve the problem of low ammonia nitrogen (N-NH₃) removal rate in the existing technology, the present invention provides a catalyst for wet oxidation degradation of high-concentration ammonia nitrogen, a preparation method, an organic wastewater treatment method and an application. The treatment method of the present invention has a high ammonia nitrogen removal rate for high-concentration ammonia nitrogen wastewater and a simple process.

[0007] One of the objectives of the present invention is to provide a wet oxidation catalyst, which includes a carrier and an active component. The active component includes at least one of platinum group elements, and the platinum group elements are derived from nitrates of at least one of the platinum group elements. The active component exists in the form of a simple substance and / or an oxide.

[0008] In a preferred embodiment of the present invention,

[0009] the platinum group elements include at least one of Ru, Pt, Pd, and Rh, preferably include at least one of Pt, Pd, and Rh; and / or,

[0010] the carrier includes at least one of TiO₂, ZrO₂, TiO₂-ZrO₂, and SiO₂.

[0011] In a preferred embodiment of the present invention,

[0012] Calculated by weight, the wet oxidation catalyst includes: 95.0 to 99.5 parts by weight of the carrier; 0.5 to 5.0 parts by weight of the active component, wherein the weight of the active component is calculated based on the platinum group elements; preferably, calculated by weight, the wet oxidation catalyst includes: 98.5 to 99.2 parts by weight of the carrier; 0.8 to 1.5 parts by weight of the active component, for example, it can be 0.9 part by weight of the active component, 1 part by weight of the active component, 1.1 parts by weight of the active component, 1.2 parts by weight of the active component, 1.3 parts by weight of the active component, 1.4 parts by weight of the active component, wherein the weight of the active component is calculated based on the platinum group elements.

[0013] In a preferred embodiment of the present invention,

[0014] The wet oxidation catalyst is prepared by a preparation method including the step of loading a nitrate solution of at least one of the platinum group elements on the carrier.

[0015] Another objective of the present invention is to provide a preparation method of the wet oxidation catalyst of one of the objectives of the present invention, which includes the step of loading a nitrate solution of at least one of the platinum group elements on the carrier.

[0016] In a preferred embodiment of the present invention,

[0017] The method includes:

[0018] 1) Shaping, drying, and calcining a group of components including a carrier precursor to obtain the carrier;

[0019] 2) Impregnating the carrier with a nitrate solution containing at least one of the platinum group elements in an equal volume, and drying and reducing to obtain the wet oxidation catalyst.

[0020] In a preferred embodiment of the present invention,

[0021] In step 1),

[0022] The carrier precursor is a powder of the carrier, preferably a powder of at least one of TiO2, ZrO2, TiO2-ZrO2, and SiO2; and / or,

[0023] The drying temperature is 80-120°C, preferably 90-110°C, and / or, the drying time is 10-16 h, preferably 11-13 h; and / or,

[0024] The calcining temperature is 650-900°C, preferably 650-750°C, and / or, the calcining time is 3.0-5.0 h, preferably 4.0-5.0 h.

[0025] Preferably,

[0026] The carrier obtained in step 1) is spherical or quasi-spherical. The diameter range of the carrier can be determined by selecting a forming die of an appropriate size according to the actual situation. In the present invention, it is preferred that the diameter of the carrier is 1-5 mm, more preferably 3 mm.

[0027] In a preferred embodiment of the present invention,

[0028] In step 2),

[0029] The weight ratio of the total weight of the platinum group elements in the nitrate solution containing at least one of the platinum group elements to the weight of the carrier is (0.5-5.0):(95.0-99.5), preferably (0.8-1.5):(98.5-99.2); and / or,

[0030] The present invention has no particular limitation on the concentration of the nitrate solution containing at least one of the platinum group elements, and it can be set according to the actual situation;

[0031] The drying temperature is 80-150°C, preferably 100-120°C, and / or, the drying time is 5-20 h, preferably 14-18 h; and / or,

[0032] The reduction temperature is 320 to 500 °C, preferably 340 to 480 °C, more preferably 380 to 420 °C, and / or the reduction time is 3.5 to 5.5 h, preferably 3.7 to 5.3 h, more preferably 4.7 to 5.3 h.

[0033] The following specific technical solutions can be adopted in the present invention:

[0034] The catalyst can be obtained by a preparation method including the following steps:

[0035] 1) Mix components including the carrier powder and the binder, form, dry, and calcine to obtain a formed carrier;

[0036] 2) Impregnate the formed carrier with a nitrate solution containing at least one of the platinum group elements in an equal volume, dry, and reduce to obtain the catalyst.

[0037] There is no particular limitation on the particle size of the carrier powder in the above technical solutions. It is obvious that the finer the powder, the more uniform the subsequent mixing. For example, but not limited to, the average particle size of TiO2 powder is 10 to 30 nm, preferably 20 nm.

[0038] There is no particular limitation on the preparation method of the carrier of the catalyst of the present invention. For example, but not limited to: tableting, rolling ball forming, extrusion forming, etc. The binder used can preferably be at least one of an organic binder and an inorganic binder, more preferably at least one of PEG, CMC, methyl cellulose, starch, nitric acid, aluminum sol, and silica sol. There is no particular limitation on the amount of the binder in the present invention, and it can be added according to actual situations.

[0039] The third object of the present invention is to provide a method for treating organic wastewater containing N-NH3, including the step of contacting the organic wastewater containing N-NH3 with an oxygen-containing oxidant for reaction in the presence of the wet oxidation catalyst of the first object of the present invention or the wet oxidation catalyst obtained by the preparation method of the second object of the present invention.

[0040] The technical key of the present invention is the selection of the catalyst. Once the catalyst is determined, those skilled in the art can reasonably select the process conditions adopted, such as but not limited to:

[0041] The content of N-NH3 in the organic wastewater containing N-NH3 is greater than 300 ppm, preferably 500 - 1500 ppm; preferably the organic wastewater is industrial ammonia nitrogen wastewater; and / or,

[0042] The oxygen-containing oxidant is oxygen or air; and / or,

[0043] The volume ratio of the oxygen-containing oxidant to the organic wastewater containing N-NH3 is (50-400):1, preferably (80-200):1; and / or,

[0044] The reaction conditions include: the temperature is 220-300 °C, preferably 240-280 °C, and / or, the pressure is 5.0-10.0 MPa, preferably 6.0-8.5 MPa, and / or, the mass space velocity of the organic wastewater is 0.4-1.2 h -1 , preferably 0.6-1.0 h -1 .

[0045] A fourth object of the present invention is to provide an application of the wet oxidation catalyst of one of the objects of the present invention, or the wet oxidation catalyst obtained by the preparation method of the second object of the present invention, or the treatment method of the third object of the present invention in the treatment of organic wastewater containing N-NH3.

[0046] Adopting the technical solution of the present invention, after the industrial wastewater is mixed with oxygen and passes through a wet oxidation reactor equipped with a catalyst, at a reaction temperature of 260 °C, a pressure of 7.0 MPa, and a volume ratio of oxygen to industrial wastewater of 200, after reacting for 400 h, excellent results are obtained for the removal rate of N-NH3 in the high-concentration ammonia-nitrogen wastewater, which can be as high as more than 99%, and the method is simple and easy to industrialize. Specific Embodiments

[0047] The present invention will be specifically described below in conjunction with specific embodiments. It is necessary to point out here that the following embodiments are only for further illustration of the present invention and cannot be understood as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0048] The raw materials used in the examples and comparative examples of the present invention are all conventional commercially available products.

[0049] The evaluation method of the catalyst of the present invention is as follows: Take 100 g of the catalyst and load it into a wet oxidation reactor (the reactor is a fixed-bed reactor with an inner diameter of 22 mm and a reactor length of 700 mm). Use industrial ammonia-nitrogen wastewater with an N-NH3 value of 850 ppm as the raw material. After mixing with oxygen, pass through the wet oxidation reactor equipped with the catalyst. The reaction temperature is 220-300 °C, the pressure is 5.0-10.0 MPa, the volume ratio of oxygen to industrial ammonia-nitrogen wastewater is (50-400):1, and the mass space velocity of the industrial wastewater is 0.4-1.2 h -1 . The N-NH3 value of the reaction product is measured by a Hach DR3900 analyzer of Hach Company.

[0050]

Example 1

[0051] 1. Support Preparation

[0052] Put 99 parts by weight of TiO2 powder (average particle size 20 nm) into a kneader for mixing, pour in 3.0 parts by weight of methylcellulose and 90 parts by weight of water, carry out kneading, extrusion, and ball rolling to form pellets, dry at 100 °C for 12 h, and then calcine in a muffle furnace at 700 °C for 4.5 h to obtain spherical supports with a diameter of 3 mm.

[0053] 2. Catalyst Preparation

[0054] Impregnate 99 parts by weight of spherical supports with an equal volume of an aqueous solution of Pd(NO3)2 containing 1 part by weight of Pd, let it stand at room temperature for 4 h, then dry in an oven at 110 °C for 16 h, and then reduce in a tubular atmosphere furnace at 400 °C for 5.0 h to obtain the catalyst.

[0055] 3. Catalyst Evaluation

[0056] Take 100 g of the catalyst and load it into a wet oxidation fixed-bed reactor for reaction. The reaction temperature is 260 °C, the pressure is 7.0 MPa, the volume ratio of oxygen to industrial ammonia-nitrogen wastewater (N-NH3 value is 850 ppm) is 200:1, and the mass space velocity of the industrial wastewater is 1.0 h -1 . The N-NH3 value of the reaction product is measured using a DR3900 analyzer from Hach Company. The catalyst evaluation results are shown in Table 1.

[0057]

Comparative Example 1

[0058] 1. Support Preparation

[0059] Put 99 parts by weight of TiO2 powder (average particle size 20 nm) into a kneader for mixing, pour in 3.0 parts by weight of methylcellulose and 90 parts by weight of water, carry out kneading, extrusion, and ball rolling to form pellets, dry at 100 °C for 12 h, and then calcine in a muffle furnace at 700 °C for 4.5 h to obtain spherical supports with a diameter of 3 mm.

[0060] 2. Catalyst Preparation

[0061] Impregnate 99 parts by weight of spherical supports with an equal volume of an aqueous solution of PdCl2 containing 1 part by weight of Pd, let it stand at room temperature for 4 h, then dry in an oven at 110 °C for 16 h, and then reduce in a tubular atmosphere furnace at 400 °C for 5.0 h to obtain the catalyst.

[0062] 3. Catalyst Evaluation

[0063] Take 100 g of the catalyst and load it into a wet oxidation fixed-bed reactor for reaction. The reaction temperature is 260 °C, the pressure is 7.0 MPa, the volume ratio of oxygen to industrial ammonia-nitrogen wastewater (N-NH3 value is 850 ppm) is 200:1, and the mass space velocity of the industrial wastewater is 1.0 h -1The N-NH3 value of the reaction product was measured using a DR3900 analyzer from Hach Company. The catalyst evaluation results are shown in Table 1.

[0064]

Example 2

[0065] 1. Support preparation.

[0066] 99 parts by weight of TiO2 powder (average particle size 20 nm) were put into a kneader for mixing, and 3.0 parts by weight of methyl cellulose and 90 parts by weight of water were poured in. Kneading, extrusion, and rolling ball forming were carried out, followed by drying at 100 °C for 12 h, and then calcining in a muffle furnace at 650 °C for 4.8 h to obtain spherical supports with a diameter of 3 mm.

[0067] 2. Catalyst preparation.

[0068] An aqueous solution of Rh(NO3)3 containing 1 part by weight of Rh was impregnated on 99 parts by weight of the spherical support in an equal volume, and left standing at room temperature for 4 h. Subsequently, it was dried in an oven at 110 °C for 16 h, and then reduced in a tubular atmosphere furnace at 380 °C for 5.2 h to obtain the catalyst.

[0069] 3. The catalyst evaluation was the same as in Example 1. The catalyst evaluation results are shown in Table 1.

[0070]

Comparative Example 2

[0071] 1. The support preparation was the same as in Example 2.

[0072] 2. In the catalyst preparation, except that Rh(NO3)3 was replaced by RhCl3, the others were the same as in Example 2.

[0073] 3. The catalyst evaluation was the same as in Example 2. The catalyst evaluation results are shown in Table 1.

[0074]

Example 3

[0075] 1. Support preparation.

[0076] 99 parts by weight of TiO2 powder (average particle size 20 nm) were put into a kneader for mixing, and 3.0 parts by weight of methyl cellulose and 90 parts by weight of water were poured in. Kneading, extrusion, and rolling ball forming were carried out, followed by drying at 100 °C for 12 h, and then calcining in a muffle furnace at 720 °C for 4.3 h to obtain spherical supports with a diameter of 3 mm.

[0077] 2. Catalyst preparation.

[0078] An aqueous solution of Pt(NO3)2 containing 1 part by weight of Pt was impregnated on 99 parts by weight of the spherical support in an equal volume, and left standing at room temperature for 4 h. Subsequently, it was dried in an oven at 110 °C for 16 h, and then reduced in a tubular atmosphere furnace at 420 °C for 4.8 h to obtain the catalyst.

[0079] 3. The catalyst evaluation was the same as in Example 1. The catalyst evaluation results are shown in Table 1.

[0080]

Comparative Example 3

[0081] 1. The carrier preparation was the same as in Example 3.

[0082] 2. For the catalyst preparation, except that Pt(NO3)2 was replaced with PtCl2, the others were the same as in Example 3.

[0083] 3. The catalyst evaluation was the same as in Example 3. The catalyst evaluation results are shown in Table 1.

[0084]

Example 4

[0085] 1. The carrier preparation was the same as in Example 1.

[0086] 2. Catalyst preparation.

[0087] An aqueous solution of Pd(NO3)2 containing 2 parts by weight of Pd was impregnated on 98 parts by weight of a spherical carrier in an equal volume, left to stand at room temperature for 4 h, then dried in an oven at 110 °C for 16 h, and then reduced in a tubular atmosphere furnace at 400 °C for 5.0 h to obtain the catalyst.

[0088] 3. The catalyst evaluation was the same as in Example 1. The catalyst evaluation results are shown in Table 1.

[0089]

Example 5

[0090] 1. The carrier preparation was the same as in Example 1.

[0091] 2. Catalyst preparation.

[0092] An aqueous solution of Pd(NO3)2 containing 0.6 parts by weight of Pd was impregnated on 99.4 parts by weight of a spherical carrier in an equal volume, left to stand at room temperature for 4 h, then dried in an oven at 110 °C for 16 h, and then reduced in a tubular atmosphere furnace at 400 °C for 5.0 h to obtain the catalyst.

[0093] 3. The catalyst evaluation was the same as in Example 1. The catalyst evaluation results are shown in Table 1.

[0094]

Comparative Example 4

[0095] 1. The carrier preparation was the same as in Example 3.

[0096] 2. Catalyst preparation

[0097] An aqueous solution of H2PtCl6 containing 1 part by weight of Pt was impregnated on 99 parts by weight of a spherical carrier in an equal volume, left to stand at room temperature for 4 h, then dried in an oven at 110 °C for 16 h, and then reduced in a tubular atmosphere furnace at 420 °C for 4.8 h to obtain the catalyst.

[0098] 3. The catalyst evaluation was the same as in Example 3. The catalyst evaluation results are shown in Table 1.

[0099]

Comparative Example 5

[0100] 1. The carrier preparation was the same as in Example 1.

[0101] 2. Catalyst preparation

[0102] An aqueous solution of PdSO4 containing 1 part by weight of Pd was impregnated on 99 parts by weight of a spherical carrier in an equal volume, left standing at room temperature for 4 h, then dried in an oven at 110 °C for 16 h, and then reduced in a tubular atmosphere furnace at 400 °C for 5.0 h to obtain the catalyst.

[0103] 3. The catalyst evaluation was the same as in Example 1. The catalyst evaluation results are shown in Table 1.

[0104]

Comparative Example 6

[0105] 1. The carrier preparation was the same as in Example 2.

[0106] 2. Catalyst preparation

[0107] An aqueous solution of Rh2(SO4)3 containing 1 part by weight of Rh was impregnated on 99 parts by weight of a spherical carrier in an equal volume, left standing at room temperature for 4 h, then dried in an oven at 110 °C for 16 h, and then reduced in a tubular atmosphere furnace at 380 °C for 5.2 h to obtain the catalyst.

[0108] 3. The catalyst evaluation was the same as in Example 2. The catalyst evaluation results are shown in Table 1.

[0109] Table 1

[0110]

[0111] It can be seen from Examples 1-5, Comparative Examples 1-6 and Table 1 that when the nitrate solutions of Ru, Pt, Pd, and Rh are used as the precursor solutions of the active components in the present invention, the finally obtained wet oxidation catalyst has significantly better removal rate for N-NH3.

[0112] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications having the same function.

[0113] All publications, patent applications, patents, and other references mentioned in this specification are hereby incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by one of ordinary skill in the art. In case of conflict, the definitions in this specification shall prevail.

[0114] When this specification uses prefixes such as "well-known to those skilled in the art", "prior art", or their similar terms to introduce materials, substances, methods, steps, devices, or components, etc., the objects introduced by such prefixes cover those commonly used in the art at the time when this application is filed, but also include those that are not commonly used currently but will become recognized in the art as suitable for similar purposes.

[0115] In the scope disclosed in this application document, the endpoints and any values of the scope are not limited to the exact scope or value. These scopes or values should be understood to include values close to these scopes or values. For numerical ranges, the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein. In the following text, in principle, various technical solutions can be combined with each other to obtain new technical solutions, and this should also be regarded as specifically disclosed herein.

[0116] In the context of this specification, any matter or thing not mentioned, except as explicitly stated, directly applies to those known in the art without any change.

[0117] Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or technical ideas thus formed shall be regarded as part of the original disclosure or original record of the present invention, and shall not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider such combination to be obviously unreasonable.

Claims

1. A wet oxidation catalyst, comprising a carrier and an active component, wherein the active component comprises at least one of platinum group elements, and the platinum group element is derived from nitrates of at least one of the platinum group elements.

2. The wet oxidation catalyst according to claim 1, wherein: the platinum group element comprises at least one of Ru, Pt, Pd, and Rh, preferably at least one of Pt, Pd, and Rh; and / or, the carrier comprises at least one of TiO2, ZrO2, TiO2-ZrO2, and SiO2.

3. The wet oxidation catalyst according to claim 1, wherein: by weight, the wet oxidation catalyst comprises: 95.0 - 99.5 parts by weight of the carrier; 0.5 - 5.0 parts by weight of the active component, wherein the weight of the active component is calculated based on the platinum group element; preferably, by weight, the wet oxidation catalyst comprises: 98.5 - 99.2 parts by weight of the carrier; 0.8 - 1.5 parts by weight of the active component, wherein the weight of the active component is calculated based on the platinum group element.

4. The wet oxidation catalyst according to any one of claims 1 - 3, wherein: the wet oxidation catalyst is prepared by a preparation method comprising the step of loading the carrier with a nitrate solution of at least one of the platinum group elements.

5. A preparation method of the wet oxidation catalyst according to any one of claims 1 - 4, comprising the step of loading the carrier with a nitrate solution of at least one of the platinum group elements.

6. The preparation method according to claim 5, characterized in that The method comprises: 1) Shaping, drying, and calcining a composition including a carrier precursor to obtain the carrier; 2) Equally volumetrically impregnating the carrier with a nitrate solution containing at least one of the platinum group elements, and drying and reducing to obtain the wet oxidation catalyst.

7. The preparation method according to claim 6, wherein: in step 1), the drying temperature is 80 - 120 °C, preferably 90 - 110 °C, and / or, the drying time is 10 - 16 h, preferably 11 - 13 h; and / or, the calcining temperature is 650 - 900 °C, preferably 650 - 750 °C, and / or, the calcining time is 3.0 - 5.0 h, preferably 4.0 - 5.0 h.

8. The preparation method according to claim 6, wherein: in step 2), the weight ratio of the total weight of the platinum group element in the nitrate solution of at least one of the platinum group elements to the weight of the carrier is (0.5 - 5.0):(95.0 - 99.5), preferably (0.8 - 1.5):(98.5 - 99.2); and / or, the drying temperature is 80 - 150 °C, preferably 100 - 120 °C, and / or, the drying time is 5 - 20 h, preferably 14 - 18 h; and / or, the reduction temperature is 320 - 500 °C, preferably 340 - 480 °C, and the reduction time is 3.5 - 5.5 h, preferably 3.7 - 5.3 h.

9. A method for treating organic wastewater containing N-NH3, comprising the step of contacting and reacting the organic wastewater containing N-NH3 with an oxygen-containing oxidant in the presence of the wet oxidation catalyst according to any one of claims 1-4 or the wet oxidation catalyst obtained by the preparation method according to any one of claims 5-8.

10. The method according to claim 9, characterized in that: the content of N-NH3 in the organic wastewater containing N-NH3 is greater than 300 ppm, preferably 500-1500 ppm; and / or, the oxygen-containing oxidant is oxygen or air; and / or, the volume ratio of the oxygen-containing oxidant to the organic wastewater containing N-NH3 is (50-400):1, preferably (80-200):1; and / or, The conditions of the reaction include: the temperature is 220 to 300 °C, preferably 240 to 280 °C, and / or the pressure is 5.0 to 10.0 MPa, preferably 6.0 to 8.5 MPa, and / or the mass space velocity is 0.4 to 1.2 h -1 , preferably 0.6 to 1.0 h -1 .

11. Use of the wet oxidation catalyst according to any one of claims 1-4 or the wet oxidation catalyst obtained by the preparation method according to any one of claims 5-8 or the method according to any one of claims 9-10 in the treatment of organic wastewater containing N-NH3.

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