CN115970680A - A kind of wet oxidation catalyst and its preparation method and application - Google Patents

Abstract

The invention belongs to the technical field of catalytic synthesis, and in particular relates to a wet oxidation catalyst and its preparation method and application. The wet oxidation catalyst provided by the present invention includes a _TiO2 carrier and noble metal _M1 and noble metal _M2 loaded on the _TiO2 carrier; the noble metal _M1 is Ru, Pt, Pd or Rh; the noble metal _M2 is Ru , Pt, Pd or Rh; the noble metal M ₁ and the noble metal M ₂ are partially covered by the TiO ₂ carrier. The wet oxidation catalyst provided by the invention mainly includes a TiO ₂ carrier and active components M ₁ and M ₂ loaded on the TiO ₂ carrier, and has high activity and good anti-loss performance. When the wet oxidation catalyst provided by the invention is used for the treatment of organic amine wastewater, it has high catalytic activity, and the active components are not easy to be lost, thereby greatly reducing the cost of organic amine wastewater treatment.

Description

A kind of wet oxidation catalyst and its preparation method and application

technical field

The invention belongs to the technical field of catalytic synthesis, and in particular relates to a wet oxidation catalyst and its preparation method and application.

Background technique

Organic amine wastewater mainly comes from industries such as leather, tires, and textiles. It mainly contains methylamine, triethylamine, ammonia, and other trace by-products. It is a high-nitrogen, low-carbon wastewater with high concentration, strong toxicity, and refractory biodegradation. . The direct discharge of untreated organic amine wastewater will cause great harm to the human body and the surrounding environment. Due to the toxicity of organic amine wastewater, it is difficult to treat organic amine wastewater with biological treatment technology.

At present, scholars at home and abroad mainly use chemical and physical methods to degrade organic amine wastewater, among which catalytic oxidation has become a research hotspot due to its large treatment capacity, excellent degradation effect and short treatment time. Among them, catalytic wet oxidizers can efficiently treat organic amine wastewater, but the existing catalysts are not stable and the active components are easy to lose.

As a representative of solid acid catalyst, ZSM-5 molecular sieve (high silica zeolite) can be applied to various catalytic reactions, but its pore size is too small, and the pore size will limit the catalytic degradation performance of organic amine wastewater. Wu Zhen, Zhang Panyue, etc. found that the use of strong alkali to modify ZSM-5 molecular sieve can expand the pore size and solve the problem of the limitation of micropore size on catalytic degradation, but the pore formation rate and depth are not easy to control, and the micropores on the outer surface are large. Partially destroyed, the stability of ZSM-5 molecular sieve is greatly reduced, and the active components are easy to lose.

To sum up, how to obtain a catalyst whose active components are not easy to lose on the basis of ensuring the catalytic activity is a difficult problem faced by those skilled in the art.

Contents of the invention

The object of the present invention is to provide a wet oxidation catalyst and its preparation method and application. The wet oxidation catalyst provided by the present invention has high activity and good anti-loss performance.

In order to achieve the above object, the present invention provides the following technical solutions:

The present invention provides a wet oxidation catalyst, comprising a _TiO2 carrier and a noble metal _M1 and a noble metal _M2 loaded on the _TiO2 carrier; the noble metal _M1 is Ru, Pt, Pd or Rh; the noble metal M ₂ is Ru, Pt, Pd or Rh; the noble metal M ₁ and noble metal M ₂ are partially covered by the TiO ₂ carrier.

Preferably, the content of noble metal _M1 in the wet oxidation catalyst is 0.001-1wt%, the content of noble metal _M2 is 0.005-5wt%, and the rest is _TiO2 carrier.

The present invention also provides a preparation method for the wet oxidation catalyst described in the above scheme, comprising the following steps:

Mix TiO ₂ , NaOH, water and the precursor salt of the noble metal M ₁ and then perform hydrothermal treatment and first thermal reduction in sequence to obtain TiO ₂ (M ₁ /TiO ₂ ) loaded with the noble metal M ₁ ;

The TiO ₂ loaded with the noble metal M ₁ is mixed with the precursor salt of the noble metal M ₂ and ethylene glycol, followed by an alcohol thermal reduction reaction and a second thermal reduction to obtain a wet oxidation catalyst.

Preferably, the temperature of the hydrothermal treatment is 50-200° C., and the holding time is 5-50 hours.

Preferably, the first thermal reduction is as follows: heating the reaction system to 300-600°C in a protective gas, switching the protective gas to H ₂ , performing a constant temperature reduction reaction for 0.5-5 hours, and then switching H ₂ to a protective gas and cool to room temperature.

Preferably, before the first thermal reduction, it also includes: sequentially cooling, filtering, washing to neutrality and drying the product obtained by the hydrothermal treatment;

Before the second thermal reduction, it also includes: sequentially filtering the product obtained in the alcohol thermal reduction reaction, washing with water until the filtrate is free of Cl ⁻ and drying.

Preferably, the alcohol thermal reduction reaction is as follows: adjust the pH value of the mixture of TiO ₂ loaded with noble metal M ₁ , the precursor salt of noble metal M ₂ and ethylene glycol to 6-12, raise the temperature to 50-150°C and keep it warm for 1- 5h, then the obtained reaction product was cooled to room temperature, and the pH value was adjusted to below 3, and the reaction was continued for 1-15h; the alcohol thermal reduction reaction was carried out in a protective gas.

Preferably, the second thermal reduction is: a constant temperature reduction reaction at 300-600° C. for 2-12 hours in a hydrogen atmosphere.

Preferably, the noble metal M ₁ precursor salt is a soluble salt of Ru, Pt, Pd or Rh; the noble metal M ₂ precursor salt is a soluble salt of Ru, Pt, Pd or Rh.

The present invention also provides the application of the wet oxidation catalyst described in the above scheme or the wet oxidation catalyst obtained by the preparation method described in the above scheme in the treatment of organic amine wastewater.

The present invention provides a wet oxidation catalyst, comprising a _TiO2 carrier and a noble metal _M1 and a noble metal _M2 loaded on the _TiO2 carrier; the noble metal _M1 is Ru, Pt, Pd or Rh; the noble metal M ₂ is Ru, Pt, Pd or Rh; the noble metal M ₁ and noble metal M ₂ are partially covered by the TiO ₂ carrier. The wet oxidation catalyst provided by the present invention mainly includes a TiO ₂ carrier and active components noble metal M ₁ and noble metal M ₂ supported on the TiO ₂ carrier, the active components noble metal M ₁ and noble metal M ₂ are partially covered by the TiO ₂ carrier, and part Bare, this special structure makes the wet oxidation catalyst of the present invention have high activity and good anti-loss performance. Wherein, the noble metal _M1 and the noble metal _M2 are partially coated, so that the wet oxidation catalyst of the present invention has good anti-loss performance, and the noble metal _M1 and the noble metal _M2 are partially exposed, so that the wet oxidation catalyst of the present invention has good catalytic activity .

The present invention also provides a method for preparing the wet oxidation catalyst described in the above scheme. The present invention ensures that the TiO ₂ carrier coats the precursor salt of the noble metal M ₁ through hydrothermal treatment, and then reduces the precursor salt of the noble metal M ₁ to the noble metal M ₁ through the first thermal reduction, at this time, most of the noble metal M ₁ is covered by the TiO ₂ carrier Then through the alcohol thermal reduction reaction, it is guaranteed that the noble metal _M2 is in situ immobilized on the exposed site of the noble metal _M1 (the noble metal _M1 can decompose ethylene glycol to generate active hydrogen species, and the active hydrogen species can reduce the noble metal _M2 precursor salt , so the noble metal _M2 generated by the alcohol thermal reduction reaction must be at the position of the noble metal _M1 ), the second thermal reduction makes the _TiO2 carrier partially cover the noble metal _M2 , and finally the wet oxidation catalyst is prepared. The preparation method provided by the invention has the advantages of convenient operation, environmental protection and good safety.

The present invention also provides the application of the wet oxidation catalyst described in the above scheme or the wet oxidation catalyst obtained by the preparation method described in the above scheme in the treatment of organic amine wastewater. The wet oxidation catalyst provided by the invention has high catalytic activity when used in the treatment of organic amine wastewater, and the active components are not easy to lose, thereby reducing the cost of organic amine wastewater treatment.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without paying creative labor.

Figure 1 is an electron micrograph of the Pt-0.5Pt%/ _TiO2 wet oxidation catalyst prepared in Example 1 of the present invention.

Detailed ways

The present invention provides a wet oxidation catalyst, comprising a _TiO2 carrier and a noble metal _M1 and a noble metal _M2 loaded on the _TiO2 carrier; the noble metal _M1 is Ru, Pt, Pd or Rh; the noble metal M ₂ is Ru, Pt, Pd or Rh; the noble metal M ₁ and noble metal M ₂ are partially covered by the TiO ₂ carrier.

The wet oxidation catalyst provided by the present invention includes a TiO ₂ carrier; the content of the TiO ₂ carrier in the wet oxidation catalyst is preferably 94-99.994wt%, more preferably 95-99wt%, even more preferably 96-98wt%.

The wet oxidation catalyst provided by the present invention includes noble metal M ₁ and noble metal M ₂ supported on the TiO ₂ carrier; the noble metal M ₁ is Ru, Pt, Pd or Rh; the noble metal M ₂ is Ru, Pt, Pd or Rh; the content of noble metal _M1 in the wet oxidation catalyst is preferably 0.001 to 1 wt%, more preferably 0.01 to 0.8 wt%, further preferably 0.1 to 0.5 wt%; the content of noble metal _M2 in the wet oxidation catalyst Preferably it is 0.005-5 wt%, More preferably, it is 0.01-3 wt%, More preferably, it is 0.1-1 wt%. In the present invention, the general formula of the wet oxidation catalyst is M ₂ -M ₁ /TiO ₂ .

The present invention also provides a preparation method for the wet oxidation catalyst described in the above scheme, comprising the following steps:

Mix TiO ₂ , NaOH, water and the precursor salt of the noble metal M ₁ and then perform hydrothermal treatment and first thermal reduction in sequence to obtain TiO ₂ (M ₁ /TiO ₂ ) loaded with the noble metal M ₁ ;

The TiO ₂ loaded with the noble metal M ₁ is mixed with the precursor salt of the noble metal M ₂ and ethylene glycol, followed by an alcohol thermal reduction reaction and a second thermal reduction to obtain a wet oxidation catalyst.

In the present invention, TiO ₂ , NaOH, water and the precursor salt of noble metal M ₁ are mixed, followed by hydrothermal treatment and first thermal reduction to obtain TiO ₂ (M ₁ /TiO ₂ ) loaded with noble metal M ₁ . In the present invention, the TiO ₂ is commercially available TiO ₂ ; the noble metal M ₁ precursor salt is preferably a soluble salt of Ru, Pt, Pd or Rh; the soluble salt of Pt is preferably H ₂ PtCl ₆ ·6H ₂ O; the soluble salt of Pd is preferably PdCl ₂ ; the soluble salt of Rh is preferably RhCl ₃ ·3H ₂ O; the mass ratio of TiO ₂ to NaOH is preferably 1-10:10-100, more preferably 2～9:15～90; the mass ratio of the TiO ₂ and water is preferably 1～10:15～200, more preferably 2～9:20～180; the mass ratio of the TiO ₂ and the noble metal M ₁ precursor salt The ratio is preferably 1-10000:10000-16000, more preferably 2-1000:10000-15500; the temperature of the hydrothermal treatment is preferably 50-200°C, more preferably 90-150°C, and even more preferably 120°C. The time is preferably 5 to 50 hours, more preferably 10 to 40 hours, and further preferably 20 to 30 hours; the hydrothermal treatment equipment is preferably a polytetrafluoroethylene-lined reactor; before the first thermal reduction, it is also preferable to include: The product obtained by the hydrothermal treatment is cooled, filtered, washed to neutral and dried in sequence; the final temperature of the cooling is preferably room temperature; the filtration is preferably suction filtration; the washing reagent is preferably deionized water; The drying temperature is preferably 40 to 120°C, more preferably 60 to 90°C.

In the present invention, the first thermal reduction is preferably: raising the temperature of the reaction system to 300-600°C in the protective gas, switching the protective gas to H ₂ , performing a constant temperature reduction reaction for 0.5-5 hours, and then switching the H ₂ It is a protective gas and cooled to room temperature; the equipment for the first thermal reduction is preferably an atmosphere furnace; the protective gas is preferably nitrogen or argon. In the present invention, the mixing of the TiO ₂ , NaOH, water and the precursor salt of the noble metal M ₁ is preferably: uniformly mixing the TiO ₂ and the aqueous NaOH solution, and then mixing the resulting mixture with the precursor salt of the noble metal M 1 .

After obtaining the TiO ₂ (M ₁ /TiO ₂ ) loaded with the noble metal M ₁ , the present invention mixes the M ₁ /TiO ₂ , the precursor salt of the noble metal M ₂ , and ethylene glycol, and then performs alcohol thermal reduction reaction and second thermal reduction in sequence. , to obtain a wet oxidation catalyst. In the present invention, the noble metal M ₂ is preferably Ru, Pt, Pd or Rh; the mass ratio of M ₁ /TiO ₂ to ethylene glycol is preferably 1-10:2-20, more preferably 2-9 : 3 to 18; the mixing of M ₁ /TiO ₂ , the noble metal M ₂ precursor salt, and ethylene glycol is preferably: after ethylene glycol and M ₁ /TiO ₂ are ultrasonically mixed, an inert gas is introduced and stirred at room temperature (denoted as The first stirring), then add the ethylene glycol solution of the noble metal _M2 precursor salt and stir at room temperature (referred to as the second stirring); the M ₁ /TiO ₂ , noble metal _M2 precursor salt, and ethylene glycol mixing equipment are preferably Three-necked round bottom flask; the ultrasonic equipment is preferably a sonicator; the ultrasonic time is preferably 0.5～5h, more preferably 2～4h; the oil bath heating equipment is preferably an oil bath; the first The stirring time is preferably 10-60 min, more preferably 30-50 min; the second stirring time is preferably 10-60 min, more preferably 40-50 min.

In the present invention, the alcohol thermal reduction reaction is preferably: adjusting the pH value of the mixture of TiO ₂ loaded with noble metal M ₁ , the precursor salt of noble metal M ₂ and ethylene glycol to 6-12 (referred to as the first pH value) , be heated to 50～150 ℃ (recorded as the first temperature) insulation reaction 1～5h (recorded as the first reaction time), then the obtained reaction product is cooled to room temperature and the pH value is adjusted to below 3 (recorded as the second pH value ), continue to react for 1 to 15 hours (recorded as the second reaction time); the first pH value is preferably 7 to 11, more preferably 8 to 10; adjust the TiO ₂ and noble metal M ₂ precursors loaded with noble metal M ₁ The reagent used for the pH value of _the mixture of salt and ethylene glycol is preferably NaOH ethylene glycol solution; after adjusting the pH value of the mixture of TiO ₂ , noble metal M ₂ precursor salt and ethylene glycol, the resulting product is preferably Stirring (denoted as the third stirring); the time for the third stirring is preferably 10-60 min, more preferably 20-50 min; the first temperature is preferably 60-130°C, more preferably 80-110°C; The first reaction time is preferably 2 to 5 hours, more preferably 3 to 4 hours; the second pH value is preferably 1 to 3, more preferably 1 to 2; the obtained reaction product is cooled to room temperature to adjust the pH The reagent used is preferably hydrochloric acid; the second reaction time is preferably 6-12 hours, more preferably 8-10 hours; the alcohol thermal reduction reaction is preferably carried out in a protective gas; the protective gas is preferably nitrogen or argon.

In the present invention, the second thermal reduction is preferably: constant temperature reduction reaction at 300-600°C for 2-12 hours in a hydrogen atmosphere; the temperature of the second thermal reduction is preferably 350-550°C, more preferably 400-500°C °C, the time for the second thermal reduction is preferably 3-10 h, more preferably 5-8 h. In the present invention, before the second thermal reduction, it is preferred to further include: sequentially filtering the product obtained in the alcohol thermal reduction reaction, washing with water until the filtrate is Cl ^- free and drying; the filtering is preferably vacuum filtration; the washing with water The reagent used is preferably deionized water; the drying equipment is preferably a vacuum drying oven, the drying temperature is preferably 40-120°C, more preferably 60-100°C, further preferably 80°C, and the holding time is preferably 2 ~48h, more preferably 10~30h.

The present invention also provides the application of the wet oxidation catalyst described in the above scheme or the wet oxidation catalyst obtained by the preparation method described in the above scheme in the treatment of organic amine wastewater.

In the present invention, the application of the wet oxidation catalyst in the treatment of organic amine wastewater preferably includes the following steps: mixing the wet oxidation catalyst and organic amine wastewater to carry out catalytic oxidation reaction. In the present invention, the mass ratio of the wet oxidation catalyst to the organic amine wastewater is preferably 1-10:100-3000, more preferably 2-8:150-2800.

In order to further illustrate the present invention, the solutions of the present invention are described in detail below in conjunction with the examples, but they should not be understood as limiting the protection scope of the present invention.

Example 1

A preparation method for a wet oxidation catalyst, comprising the steps of:

(1) After uniformly mixing TiO ₂ and NaOH aqueous solution, add 0.0665 g of noble metal precursor salt H ₂ PtCl ₆ 6H ₂ O to obtain a mixed solution;

(2) Transfer the mixed solution to a polytetrafluoroethylene liner, hydrothermally treat it at 140°C for 20 hours, and after cooling to room temperature, wash it with deionized water until the pH value of the filtrate is neutral. Dry the powder at 100°C to obtain noble metal-modified TiO ₂ ;

(3) Place the obtained noble metal-modified TiO ₂ solid powder in an atmosphere furnace, heat up to 500°C in nitrogen, switch the inert gas to H ₂ , and perform a constant temperature reduction treatment for 2 hours. After the reduction, switch the H ₂ to inert gas and cooled to room temperature to obtain Pt/TiO ₂ ;

(4) Add ethylene glycol and Pt/TiO ₂ into a three-necked round-bottomed flask, and place it in a sonicator for 2 hours of sonication;

(5) Transfer the three-neck round bottom flask to an oil bath, feed inert gas to drive out the air in the bottle, stir at room temperature for 40min, measure 6.65mL of 10g/LH ₂ PtCl ₆ ethylene glycol solution and add the precious metal precursor salt Into the three-necked flask, stirred at room temperature for 40min;

(6) Add NaOH ethylene glycol solution to the solution obtained above, adjust the pH value to 8, continue to stir for 40 minutes, then raise the temperature to 120 ° C and react for 3 hours, and continue to pass nitrogen protection during the whole process;

(7) Stop heating after the reaction is over, adjust the pH value to 2 with hydrochloric acid solution after cooling to room temperature, continue to stir for 8 hours, vacuum filter the obtained solid-liquid mixture, and wash with deionized water until the filtrate is free of ^Cl- , then the obtained The material was placed in a vacuum drying oven, dried at 100°C for 24h, and then heat-treated at 400°C for 4h in a hydrogen atmosphere to obtain a 0.5% Pt-0.5Pt%/TiO ₂ catalyst, the appearance of which is shown in Figure 1.

Fig. 1 is the Pt-0.5Pt%/ _TiO2 catalyst photomicrograph prepared by the present embodiment, as can be seen from Fig. 1, the Pt active component (black particle) part is covered by _TiO2 carrier (contrast around the Pt nanoparticle The color is lighter and shiny).

Example 2

The difference between this example and Example 1 is that 0.069g of Na ₂ PdCl ₄ solid is added in step (1), and the others are the same as in Example 1 to obtain a 0.5% Pt-0.5Pd%/TiO ₂ catalyst.

Example 3

The difference between this embodiment and Example 1 is that 6.9 mL of 10 g/L Na ₂ PdCl ₄ ethylene glycol solution is added in step (5), and the others are the same as in Example 1 to obtain 0.5% Pd-0.5Pt %/TiO ₂ catalyst.

Example 4

The difference between this embodiment and Example 1 is that 0.064g of RhCl ₃ 3H ₂ O solid is added in the step (1), and others are the same as in Example 1 to obtain 0.5% Pt-0.5Rh%/ _TiO catalyzer .

Example 5

The present embodiment is different from Example 1 in that what was added in the step (5) was 6.4mL of 10g/L RhCl ₃ ethylene glycol solution, and others were the same as in Example 1 to obtain 0.5% Rh-0.5Pt%/ _TiO2 catalyst.

Comparative example 1

The difference between this comparative example and Example 1 is that 0.133g of H ₂ PtCl ₆ 6H ₂ O noble metal precursor salt was added in step (1), and the catalyst preparation was completed in step (3), and the catalyst was recorded as 1Pt%/ TiO ₂ .

Comparative example 2

The difference between this comparative example and Example 1 is that the catalyst preparation starts from step (4), adding ethylene glycol and TiO ₂ , and step (5) measures 13.3mL of 10g/L H ₂ PtCl ₆ ethylene glycol solution Noble metal, the catalyst is recorded as 1Pt%-TiO ₂ .

The wet oxidation catalysts prepared in _Examples 1 to 5 of the present invention were tested for their catalytic oxidation performance. The test conditions were: 0.1 g of 0.5% Pt-Pt/TiO catalyst and 10 mL of waste water with a pH value of 10 (dimethyl formaldehyde The amide content is 1000ppm, the COD content is 1300mg/L), and placed in a high-pressure reactor, and the catalytic reaction is carried out at a temperature of 180°C and a pressure of 2MPa for 2 hours; Nessler's reagent method is used to detect ammonia nitrogen content, and ICP detection The active components are lost, and the metal loss rate of the catalyst after the catalytic reaction, the conversion rate of ammonia nitrogen in the waste water and the removal rate of COD are calculated, and the results are shown in Table 1.

Catalytic oxidation performance of the wet oxidation catalyst prepared in table 1 embodiment 1～5

Example COD conversion rate (%) Ammonia nitrogen conversion rate (%) Metal loss rate (%) 1 98.3 97.5 Churn not detected 2 96.6 95.2 Churn not detected 3 97.2 96.8 Churn not detected 4 99.1 98.3 Churn not detected 5 98.5 97.1 Churn not detected

The catalysts prepared in Comparative Examples 1-2 of the present invention were tested for catalytic oxidation performance under the same test conditions as above, and the results are shown in Table 2.

The catalytic oxidation performance of the catalyst prepared in Table 2 Comparative Examples 1-2

comparative example COD conversion rate (%) Ammonia nitrogen conversion rate (%) Metal loss rate (%) 1 58.7 47.8 Churn not detected 2 91.9 90.2 26.1

It can be seen from Table 1 and Table 2 that in Comparative Example 1, a double amount of noble metal precursor salt was added to prepare a single metal catalyst 1Pt%/TiO ₂ , and in Comparative Example 2, a double amount of noble metal precursor salt was added to prepare a single metal catalyst 1Pt%/TiO ₂ , and the present invention adds the noble metal precursor salt twice to prepare the wet oxidation catalyst. Compared with the single metal catalysts prepared in Comparative Example 1 and Comparative Example 2, the wet oxidation catalyst prepared by the present invention has a high catalytic efficiency of up to 99.1%, an ammonia nitrogen conversion rate of up to 98.3%, and no metal loss. It can be seen that the present invention provides The wet oxidation catalyst used in organic amine wastewater treatment has high catalytic activity, and the active components are not easy to lose, which reduces the cost of organic amine wastewater treatment. In addition, comparative example 1 only carried out hydrothermal treatment and first thermal reduction, and most of the noble metals of the prepared catalyst were coated, and the active sites were insufficient, resulting in poor catalytic performance of the catalyst.

It can be seen from the above examples that the wet oxidation catalyst provided by the present invention is used for the treatment of organic amine wastewater, has high catalytic activity and is not easy to lose active components.

Although the foregoing embodiment has described the present invention in detail, it is only a part of the embodiments of the present invention, rather than all embodiments, and other embodiments can also be obtained according to the present embodiment without inventive step, and these embodiments are all Belong to the protection scope of the present invention.

Claims (10)

1. A wet oxidation catalyst, characterized in that, comprises TiO ₂ carrier and loaded on the TiO ₂ noble metal M ₁ and noble metal M ₂ on the carrier; the noble metal M ₁ is Ru, Pt, Pd or Rh; the The noble metal M ₂ is Ru, Pt, Pd or Rh; the noble metal M ₁ and the noble metal M ₂ are partially covered by the TiO ₂ carrier. 2. The wet oxidation catalyst according to claim 1, characterized in that, in the wet oxidation catalyst, the content of noble metal _M1 is 0.001-1wt%, the content of noble metal _M2 is 0.005-5wt%, and the balance of _TiO2 carrier . 3. The preparation method of the wet oxidation catalyst according to any one of claims 1 to 2, characterized in that it comprises the following steps: Mixing TiO ₂ , NaOH, water and the precursor salt of the noble metal M ₁ is followed by hydrothermal treatment and first thermal reduction to obtain TiO ₂ loaded with the noble metal M ₁ ; The TiO ₂ loaded with the noble metal M ₁ is mixed with the precursor salt of the noble metal M ₂ and ethylene glycol, followed by an alcohol thermal reduction reaction and a second thermal reduction to obtain a wet oxidation catalyst. 4. The preparation method according to claim 3, characterized in that, the hydrothermal treatment temperature is 50-200° C., and the holding time is 5-50 h. 5. The preparation method according to claim 3, wherein the first thermal reduction is as follows: heating the reaction system to 300-600°C in a protective gas, switching the protective gas to H ₂ , and constant temperature reduction React for 0.5~5h, then switch _H2 to protective gas and cool to room temperature. 6. The preparation method according to claim 3 or 5, characterized in that, before the first thermal reduction, further comprising: sequentially cooling, filtering, washing to neutrality and drying the product obtained by the hydrothermal treatment; Before the second thermal reduction, it also includes: sequentially filtering the product obtained in the alcohol thermal reduction reaction, washing with water until the filtrate is free of Cl ⁻ and drying. _{7. The preparation method according to claim 3, characterized in that, the alcohol thermal reduction reaction is: adjusting the pH value of the mixture of TiO 2 ,} noble metal M ₂ precursor salt and ethylene glycol loaded with noble metal M to 6 ～12, heat up to 50～150°C for 1～5h, then cool the obtained reaction product to room temperature, adjust the pH value to below 3, and continue the reaction for 1～15h; the alcohol thermal reduction reaction is carried out in protective gas. 8 . The preparation method according to claim 3 , wherein the second thermal reduction is: a constant temperature reduction reaction at 300-600° C. for 2-12 hours in a hydrogen atmosphere. 9. preparation method according to claim 3, is characterized in that, described noble metal M ₁ precursor salt is the soluble salt of Ru, Pt, Pd or Rh; Described noble metal M ₂ precursor salt is Ru, Pt, Pd or Rh of soluble salts. 10. The application of the wet oxidation catalyst according to any one of claims 1 to 2 or the wet oxidation catalyst obtained by the preparation method according to any one of claims 3 to 9 in the treatment of organic amine wastewater.

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