CN115254176B

CN115254176B - Nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst and preparation method and application thereof

Info

Publication number: CN115254176B
Application number: CN202210840344.8A
Authority: CN
Inventors: 陈晨; 温明月; 田园; 陈柳; 周婧; 唐红玲; 王磊
Original assignee: Jiangsu University of Science and Technology
Current assignee: Jiangsu University of Science and Technology
Priority date: 2022-07-17
Filing date: 2022-07-17
Publication date: 2024-03-15
Anticipated expiration: 2042-07-17
Also published as: CN115254176A

Abstract

The invention discloses a nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst and a preparation method and application thereof. The preparation method comprises the following steps: mixing and stirring (3-mercaptopropyl) methyldimethoxysilane and a nitrate solution to obtain a solution A; slowly adding sodium hydroxide solution into the solution A to obtain a solution B; mixing the solution B with a sodium silicate solution, heating in a water bath, and stirring until the solution is clear to obtain a solution C; continuously condensing, refluxing, heating and stirring the solution C in an oil bath until the solution is brown to obtain a solution D; mixing the solution D with a sodium metaaluminate solution, continuously stirring, and standing until an off-white gel is formed; transferring the gel to a high-pressure reaction kettle for reaction; after the reaction is completed, cooling to room temperature, washing by using ethanol and pure water until the pH is 7, and vacuum drying to obtain the catalyst. The nano zeolite coated heavy metal cluster catalyst is efficient and stable, and can be applied to catalytic wet oxidation treatment of high-concentration alkaline residue wastewater.

Description

Nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst and preparation method and application thereof

Technical Field

The invention belongs to the technical field of environmental catalytic materials, and particularly relates to a nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst and a preparation method and application thereof.

Background

Catalytic wet oxidation is a very important and widely applied method in advanced oxidation technology, and is to oxidize organic matters and ammonia in wastewater into CO through air oxidation under the action of a certain temperature, a certain pressure and a catalyst ₂ 、H ₂ O and N ₂ And harmless substances, thereby achieving the effect of purifying the wastewater. The catalytic wet oxidation method uses a high-efficiency, stable and proper catalyst in the wet oxidation reaction process, so that the oxidation reaction can be completed under milder conditions and in shorter time, thereby reducing the temperature and pressure of the reaction, improving the oxidative decomposition capability and shortening the time required by the reaction. Meanwhile, the corrosion to equipment can be reduced, and the running cost of the equipment can be reduced. The catalytic wet oxidation technology is an effective method for widely treating high-concentration industrial wastewater, and has been rapidly developed at home and abroad. In catalytic wet oxidation technology, the choice of catalyst is the core of the technology. The preparation of the catalyst with high efficiency, stability and proper price is a key factor for the application and popularization of the catalytic wet oxidation technology. However, most of the environmental or chemical catalytic materials at present have the problems of high cost, high preparation difficulty, insignificant pollutant treatment effect and the like, so that the preparation of efficient and stable catalysts has long been the focus of attention of researchers in the development of catalytic wet oxidation technology.

The invention comprises the following steps:

aiming at the defects of the prior art, the invention provides a nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst, a preparation method and application thereof, and the catalyst can efficiently treat high-concentration alkaline residue wastewater, has stable effect and is suitable for industrial production.

In order to solve the problems in the prior art, the invention adopts the following technical scheme:

the preparation method of the nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst comprises the following steps:

step 1, mixing (3-mercaptopropyl) methyldimethoxysilane and a nitrate solution, and stirring for 45-60 minutes to obtain a solution A;

step 2, slowly adding a sodium hydroxide solution into the solution A to obtain a solution B;

step 3, mixing the solution B with a sodium silicate solution, and heating in a water bath while stirring at 60-70 ℃ until the solution is clear to obtain a solution C;

step 4, continuously condensing, refluxing, heating and stirring the solution C in an oil bath until the solution is brown to obtain a solution D;

step 5, mixing the solution D with the sodium metaaluminate solution, continuously stirring for 2-3 hours at room temperature, and standing until an off-white gel is formed;

step 6, the off-white gel is moved into a high-pressure reaction kettle for reaction;

and 7, cooling to room temperature after the reaction is finished, washing by using ethanol and pure water until the pH value of a washing solution is 7, and drying in vacuum at 75 ℃ to obtain the catalyst.

As an improvement, the nitrate solution in the step 1 is cerium nitrate solution, silver nitrate solution or zirconium nitrate solution, and the concentration is 0.1mol/L-0.5mol/L; the concentration of the (3-mercaptopropyl) methyldimethoxysilane in the solution A is 0.12-0.19mol/L.

As an improvement, the concentration of the sodium hydroxide solution in the step 2 is 1.5mol/L to 3.5mol/L, and the volume ratio of the sodium hydroxide solution to the solution A is 1:1.

As improvement, in the step 3, the concentration of the sodium silicate solution is 6.1-7.6mol/L, and the volume ratio of the sodium silicate solution to the solution B is 1:2.

the improvement is that the heating temperature of the oil bath condensation reflux in the step 4 is 105-120 ℃ and the heating time is 1-2h.

As an improvement, in the step 5, the concentration of the sodium metaaluminate solution is 5.2-7.5mol/L, the standing time is 7-10h, and the volume ratio of the sodium metaaluminate solution to the solution D is 1:3.

As an improvement, the reaction temperature of the high-pressure reaction kettle in the step 6 is 180-220 ℃ and the reaction time is 10-12h.

The nano zeolite coated heavy metal cluster catalytic material prepared based on any one of the preparation methods is provided.

The application of any nano zeolite coated heavy metal cluster catalytic material in treating high-concentration organic wastewater has the COD concentration of 145000-155000mg/L petrochemical industry high-concentration alkaline residue wastewater.

As an improvement, the temperature of the catalytic wet oxidation reaction in the application is 160-200 ℃, the reaction time is 0.5-3.0h, and the adding amount of the catalyst is 0.50-1.80g per liter of wastewater.

The beneficial effects are that:

compared with the prior art, the nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst and the preparation method and application thereof have the advantages that the prepared catalyst is nano-scale, efficient and stable, and can be applied to catalytic wet oxidation treatment of alkaline residue wastewater with COD concentration of up to 150000 mg/L. The novel high-efficiency nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst material provided by the invention can be widely applied to treatment of other high-concentration chemical organic wastewater, pharmaceutical wastewater and the like.

Drawings

FIG. 1 is a graph showing the results of catalytic wet oxidation of samples of the catalyst synthesized in example 1 under various conditions;

FIG. 2 shows the results of catalytic wet oxidation of the catalyst samples synthesized in example 1 under different conditions;

FIG. 3 is a graph showing the results of catalytic wet oxidation of the catalyst samples synthesized in example 3 under various conditions;

FIG. 4 shows the results of catalytic wet oxidation of the catalyst samples synthesized in example 3 under different conditions;

FIG. 5 is a graph showing the results of catalytic wet oxidation of the catalyst samples synthesized in example 5 under various conditions;

FIG. 6 is a graph showing the results of catalytic wet oxidation of a sample of the catalyst synthesized in example 5 under various conditions

FIG. 7 is a graph showing the results of catalytic wet oxidation of a sample of the catalyst synthesized in example 7 under various conditions

FIG. 8 is a graph showing the results of catalytic wet oxidation of the catalyst samples synthesized in example 7 under various conditions;

FIG. 9 is a graph showing the results of catalytic wet oxidation of a sample of the catalyst synthesized in example 9 under various conditions

FIG. 10 is a graph showing the results of catalytic wet oxidation of the catalyst samples synthesized in example 9 under various conditions;

FIG. 11 is a graph showing the results of catalytic wet oxidation of the catalyst samples synthesized in example 11 under various conditions;

FIG. 12 is a graph showing the results of catalytic wet oxidation of the catalyst samples synthesized in example 11 under various conditions;

FIG. 13 is a Scanning Electron Microscope (SEM) result of a catalyst sample synthesized in example 1;

FIG. 14 shows the result of a scanning electron microscope of a catalyst sample synthesized in example 3;

FIG. 15 shows the result of scanning electron microscopy of a sample of the catalyst synthesized in example 5.

FIG. 16 is a Scanning Electron Microscope (SEM) result of a catalyst sample synthesized in example 7;

FIG. 17 is a Scanning Electron Microscope (SEM) result of a catalyst sample synthesized in example 9;

FIG. 18 is a Scanning Electron Microscope (SEM) result of a catalyst sample synthesized in example 11;

FIG. 19 is a flow chart of the preparation process and application of the present invention.

Detailed Description

The invention will be further illustrated with reference to specific examples.

Example 1

1) Mixing (3-mercaptopropyl) methyldimethoxysilane with 0.16mol/L cerium nitrate solution, and stirring for 45 minutes to obtain solution A, wherein the concentration of (3-mercaptopropyl) methyldimethoxysilane in the solution A is 0.12mol/L;

2) Slowly adding 1.5mol/L sodium hydroxide solution into the solution A to obtain a solution B, wherein the volume ratio of the sodium hydroxide solution to the solution A is 1:1;

3) Mixing the solution B with 6.1mol/L sodium silicate solution, heating in a water bath at 60 ℃ and stirring until the solution is clear to obtain solution C, wherein the volume ratio of the sodium silicate solution to the solution B is 1:2;

4) Continuously condensing, refluxing, heating and stirring the solution C in an oil bath at 105 ℃ for 1.5 hours until the solution is brown to obtain a solution D;

5) Mixing the solution D with 5.5mol/L sodium metaaluminate solution, continuously stirring for 2 hours at room temperature, and standing for 7 hours until an off-white gel is formed; wherein the volume ratio of the sodium metaaluminate solution to the solution D is 1:3;

6) The off-white gel is moved into a high-pressure reaction kettle to react for 10 hours at 180 ℃;

7) After the reaction is completed, cooling to room temperature, washing by using ethanol and pure water until the pH value of a washing solution is 7, and vacuum drying at 75 ℃ to obtain the catalyst.

The catalyst prepared in the embodiment is applied to the treatment of high-concentration alkaline residue wastewater in a catalytic wet oxidation device (GCF permanent magnet rotary stirring reaction kettle), and the specific procedures are as follows:

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then, the reaction vessel was opened, a part of the supernatant was collected by a disposable syringe, filtered by a filter paper, and the residual Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) concentration in the sample were analyzed.

The initial COD concentration of the alkaline residue wastewater is 153609mg/L, and the TOC concentration is 148943mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As can be seen from fig. 1, the removal rate of wet oxidation after catalyst addition was significantly improved. If the reaction temperature is 160 ℃, the reaction time is 2.5h, the COD removal rate of the wet oxidation device without adding the catalyst on the organic wastewater is 30.35%, and the TOC removal rate is 27.41%. When 0.5g/L of catalyst is added under similar conditions, the COD removal rate of the catalytic wet oxidation on the alkaline residue wastewater is improved to 60.29%, the TOC removal rate is 57.38%, and the removal rate is improved by about 30% compared with that of a wet oxidation system. When the catalyst amount is further increased to 1.5g/L, the removal rate of COD and TOC of the wastewater by catalytic wet oxidation under similar reaction conditions is increased by about 38% compared with the wet oxidation system rate. This indicates that increasing the amount of catalyst is effective to promote the removal of wastewater contaminants by the catalytic wet oxidation system.

Example 2

The catalyst prepared in the example 1 is used for treating high-concentration alkaline residue wastewater in a catalytic wet oxidation device (GCF permanent magnet rotary stirring reaction kettle), and the specific procedures are as follows:

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then, the reaction vessel was opened, a part of the supernatant was collected by a disposable syringe, filtered by a filter paper, and the residual Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) concentration in the sample were analyzed. The initial COD concentration of the alkaline residue wastewater is 153609mg/L, and the TOC concentration is 148943mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As seen from fig. 2, the reaction temperature has a larger influence on the catalytic wet oxidation, and the higher the reaction temperature is, the more remarkable the effect of removing pollutants is. When the reaction temperature is 175 ℃ and the reaction time is 2.5h, and the catalyst addition amount is 1.5g/L, the removal rate of COD in the organic wastewater by the catalytic wet oxidation system is 87.23 percent, and the removal rate of TOC is 85.59 percent, which is improved by about 18 percent compared with the removal rate of COD and TOC when the reaction temperature is 160 ℃ under similar conditions. The reaction temperature is continuously increased to 195 ℃, and the removal rates of the catalytic wet oxidation system on COD and TOC of the wastewater are up to 95.43% and 93.25%, respectively.

Example 3

1) (3-mercaptopropyl) methyldimethoxysilane was mixed with a cerium nitrate solution at a concentration of 0.24mol/L and stirred for 45 minutes to give a solution A in which the concentration of (3-mercaptopropyl) methyldimethoxysilane in the solution A was 0.14mol/L.

2) Slowly adding 2.4mol/L sodium hydroxide solution into the solution A to obtain a solution B, wherein the volume ratio of the sodium hydroxide solution to the solution A is 1:1.

3) Mixing the solution B with 6.5mol/L sodium silicate solution, heating in a water bath at 60 ℃ and stirring until the solution is clear to obtain solution C, wherein the volume ratio of the sodium silicate solution to the solution B is 1:2.

4) Solution C was stirred under continuous reflux in an oil bath at 115℃for 1.5h until the solution became brown to give solution D.

5) Mixing the solution D with 5.9mol/L sodium metaaluminate solution, continuously stirring for 2 hours at room temperature, and standing for 8 hours until an off-white gel is formed, wherein the volume ratio of the sodium metaaluminate solution to the solution D is 1:3.

6) The off-white gel was transferred to an autoclave and reacted at 185℃for 11h.

7) Cooling to room temperature after the reaction is finished, washing by using ethanol and pure water until the pH value of a washing liquid is 7, and vacuum drying at 75 ℃ to obtain a catalyst product.

The catalyst prepared in the embodiment is utilized to treat alkaline residue wastewater in a catalytic wet oxidation device (GCF permanent magnet rotary stirring reaction kettle), and the specific procedures are as follows:

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the mixture is denseSealing the high-pressure reaction kettle, and maintaining a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then, the reaction vessel was opened, a part of the supernatant was collected by a disposable syringe, filtered by a filter paper, and the residual Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) concentration in the sample were analyzed. The initial COD concentration of the alkaline residue wastewater is 146083mg/L, and the TOC concentration is 132865mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As seen in fig. 3, the catalytic wet oxidation system has a higher efficiency in the removal of wastewater than the wet oxidation system. After the catalyst is added, the catalytic removal effect of the wastewater is obviously improved. The reaction temperature is 165 ℃, the reaction time is 2.5h, the COD removal rate of the wet oxidation device without adding the catalyst to the wastewater is 32.78%, and the TOC removal rate is 30.53%. When 0.6g/L catalyst is added, the removal rates of COD and TOC of the wastewater by catalytic wet oxidation under similar conditions are respectively 64.80%, and 61.63%, which is improved by more than 30% compared with the removal rate of pollutants of a wet oxidation system, which shows that the catalyst can effectively improve the degradation rate of alkaline residue wastewater to pollutants.

Example 4

The alkaline residue wastewater was treated in a catalytic wet oxidation apparatus (GCF permanent magnet rotary stirred tank reactor) using the catalyst prepared in example 3, and the specific procedure was:

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and stirringA non-reactive machine. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then, the reaction vessel was opened, a part of the supernatant was collected by a disposable syringe, filtered by a filter paper, and the residual Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) concentration in the sample were analyzed. The initial COD concentration of the alkaline residue wastewater is 146083mg/L, and the TOC concentration is 132865mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As seen in fig. 4, increasing the amount of catalyst and increasing the reaction temperature all promote the removal of contaminants by catalytic wet oxidation. Such as: the reaction temperature is 165 ℃, the reaction time is 2.5 hours, the catalyst addition amount is 1.3g/L, the removal rates of the catalytic wet oxidation system on the COD and TOC of the wastewater are respectively improved to 74.90 percent and 72.62 percent, and the degradation rate of pollutants of the system is improved by 10 percent compared with the system with the catalyst of 0.6g/L under similar conditions. In addition, the reaction temperature is increased to 185 ℃, the catalyst addition amount is 1.3g/L, and when the reaction time is 2.5 hours, the removal rates of the catalytic wet oxidation system on the COD and the TOC of the wastewater are further increased to 91.46 percent and 88.35 percent respectively.

Example 5

1) (3-mercaptopropyl) methyldimethoxysilane was mixed with a silver nitrate solution having a concentration of 0.25mol/L and stirred for 45 minutes to obtain a solution A in which the concentration of (3-mercaptopropyl) methyldimethoxysilane in the solution A was 0.16mol/L.

2) Slowly adding 2.2mol/L sodium hydroxide solution into the solution A to obtain a solution B, wherein the volume ratio of the sodium hydroxide solution to the solution A is 1:1.

3) Mixing the solution B with 6.9mol/L sodium silicate solution, heating in water bath (60 ℃) and stirring until the solution is clear to obtain solution C, wherein the volume ratio of the sodium silicate solution to the solution B is 1:2.

4) Solution C was stirred under continuous reflux in an oil bath at 105℃for 1.6h until the solution became brown to give solution D.

5) Mixing the solution D with 5.9mol/L sodium metaaluminate solution, continuously stirring for 2 hours at room temperature, and standing for 7 hours until an off-white gel is formed, wherein the volume ratio of the sodium metaaluminate solution to the solution D is 1:3.

6) The off-white gel was transferred to an autoclave and reacted at 190℃for 11h.

The catalyst prepared in the embodiment is utilized to treat high-concentration alkaline residue wastewater in a catalytic wet oxidation device (GCF permanent magnet rotary stirring reaction kettle), and the specific procedures are as follows:

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then the reaction vessel was opened, a part of the supernatant was taken out by a disposable syringe, and filtered by a filter paper to analyze the residual COD and TOC concentrations in the sample. The initial COD concentration of the alkaline residue wastewater is 148721mg/L, and the TOC concentration is 135761mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As can be seen from fig. 5, the addition of the catalyst can greatly increase the removal rate of pollutants in the wastewater by wet oxidation. If the reaction temperature is 170 ℃, the reaction time is 2.5h, and the removal rates of COD and TOC of the wet oxidation system on the organic wastewater are 36.53% and 33.65%, respectively. After 0.5g/L of catalyst is added, the removal rate of pollutants in wastewater by the catalytic wet oxidation system is greatly increased, and the removal rates of COD and TOC are respectively increased to 65.21% and 63.01% under similar conditions.

Example 6

The catalyst prepared in example 5 is used for treating high-concentration alkaline residue wastewater in a catalytic wet oxidation device (GCF permanent magnet rotary stirring reaction kettle), and the specific procedures are as follows:

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then the reaction kettle is opened, a part of supernatant is taken by a disposable injector, and is filtered by filter paper, and the residual COD and TOC concentration in the sample is analyzed. The initial COD concentration of the alkaline residue wastewater is 148721mg/L, and the TOC concentration is 135761mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As can be seen from fig. 6, increasing the amount of catalyst and increasing the reaction temperature significantly increases the removal rate of contaminants in the catalytic wet oxidation wastewater. Such as: when the catalyst amount is 1.5g/L, the reaction temperature is 170 ℃, the reaction time is 2.5h, the removal rates of the catalytic wet oxidation system on COD and TOC of the wastewater are 81.49% and 78.49%, respectively, and the removal rate of pollutants in the system is improved by about 15% compared with the removal rate of pollutants in the system under similar conditions of the catalyst amount of 0.5g/L, and is improved by 45% compared with the removal rate of pollutants in the wet oxidation system without the catalyst. When the reaction temperature is increased to 200 ℃, the reaction time is 2.5 hours, the catalyst amount is 1.5g/L, the removal rate of the catalytic wet oxidation system to COD is up to 98.89%, and the removal rate to TOC is 96.58%.

Example 7

1) (3-mercaptopropyl) methyldimethoxysilane was mixed with a silver nitrate solution having a concentration of 0.33mol/L and stirred for 45 minutes to obtain a solution A in which the concentration of (3-mercaptopropyl) methyldimethoxysilane in the solution A was 0.17mol/L.

3) And mixing the solution B with 7.1mol/L sodium silicate solution, heating in a water bath (60 ℃) and stirring until the solution is clear to obtain a solution C, wherein the volume ratio of the sodium silicate solution to the solution B is 1:2.

4) Solution C was stirred under reflux in an oil bath at 108℃for 1.7h until the solution became brown to give solution D.

5) Mixing the solution D with 6.4mol/L sodium metaaluminate solution, continuously stirring for 2 hours at room temperature, and standing for 8.5 hours until an off-white gel is formed, wherein the volume ratio of the sodium metaaluminate solution to the solution D is 1:3.

6) The off-white gel was transferred to an autoclave and reacted at 210℃for 12h.

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then the reaction vessel was opened, a part of the supernatant was taken out by a disposable syringe, and filtered by a filter paper to analyze the residual COD and TOC concentrations in the sample. The initial COD concentration of the wastewater is 150134mg/L and the TOC concentration is 138266mg/L. COD removal Rate= (COD _{ReactionFront part} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As seen in fig. 7, the catalytic wet oxidation system with the addition of the catalyst significantly facilitates wastewater contaminant removal. The reaction temperature is 175 ℃, the reaction time is 2.5 hours, and the removal rate of COD and TOC of a catalytic wet oxidation system added with 0.7g/L catalyst is improved by about 30 percent compared with that of a wet oxidation system.

Example 8

The catalyst prepared in the example 7 is utilized to treat high-concentration alkaline residue wastewater in a catalytic wet oxidation device (GCF permanent magnet rotary stirring reaction kettle), and the specific procedures are as follows:

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then the reaction vessel was opened, a part of the supernatant was taken out by a disposable syringe, and filtered by a filter paper to analyze the residual COD and TOC concentrations in the sample. The initial COD concentration of the wastewater is 150134mg/L and the TOC concentration is 138266mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As can be seen from fig. 8, increasing the amount of catalyst, extending the reaction time, and increasing the reaction temperature can improve the degradation efficiency of the contaminants to some extent. The reaction temperature is 190 ℃, the reaction time is 2.5 hours, and the pollutant removal rate of a catalytic wet oxidation system added with 1.4g/L catalyst is more than 90%.

Example 9

1) (3-mercaptopropyl) methyldimethoxysilane was mixed with a zirconium nitrate solution having a concentration of 0.36mol/L and stirred for 45 minutes to obtain a solution A in which the concentration of (3-mercaptopropyl) methyldimethoxysilane in the solution A was 0.18mol/L.

2) Slowly adding 3.2mol/L sodium hydroxide solution into the solution A to obtain a solution B, wherein the volume ratio of the sodium hydroxide solution to the solution A is 1:1.

3) And mixing the solution B with 7.3mol/L sodium silicate solution, heating in a water bath (60 ℃) and stirring until the solution is clear to obtain solution C, wherein the volume ratio of the sodium silicate solution to the solution B is 1:2.

4) Solution C was stirred in an oil bath at 110℃under continuous reflux with heating for 1.8h until the solution became brown to give solution D.

5) Mixing the solution D with 6.6mol/L sodium metaaluminate solution, continuously stirring for 2 hours at room temperature, and standing for 8.5 hours until an off-white gel is formed, wherein the volume ratio of the sodium metaaluminate solution to the solution D is 1:3.

6) The off-white gel was transferred to an autoclave and reacted at 200℃for 12h.

The catalyst prepared in the embodiment is utilized to treat alkaline residue wastewater in a catalytic wet oxidation device (GCF permanent magnet rotary stirring reaction kettle), and the specific procedures are as follows: 1500mL of high-concentration alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then the reaction kettle is opened, a part of supernatant is taken by a disposable injector, and is filtered by filter paper, so as to analyze the residual in the sampleCOD and TOC concentrations. The initial COD concentration of the wastewater was 152705mg/L and the TOC concentration was 140071mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As can be seen from fig. 9, the addition of the catalyst can greatly improve the removal rate of wet oxidation. In addition, the extension of the reaction time can also increase the removal effect of the wastewater. The reaction temperature is 180 ℃, the reaction time is 3.0h, and the pollutant removal rate of the catalytic wet oxidation system is 28 percent higher than that of the wet oxidation system without the catalyst when the catalyst amount is 0.6 g/L.

Example 10

The alkaline residue wastewater was treated in a catalytic wet oxidation apparatus (GCF permanent magnet rotary stirring reactor) using the catalyst prepared in this example 9, and the specific procedure was:

1500mL of high-concentration alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed, and a certain oxygen partial pressure is maintained. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then the reaction kettle is opened, a part of supernatant is taken by a disposable injector, and is filtered by filter paper, and the residual COD and TOC concentration in the sample is analyzed. The initial COD concentration of the wastewater was 152705mg/L and the TOC concentration was 140071mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As can be seen from fig. 10, the increase in the catalyst amount and the increase in the reaction temperature can improve the wastewater contaminant removal rate. When the reaction temperature is 195 ℃, the reaction time is 3.0h and the catalyst amount is 1.8g/L, the removal rates of the catalytic wet oxidation system on COD and TOC of the organic wastewater are up to 96.73% and 94.50%, respectively.

Example 11

1) (3-mercaptopropyl) methyldimethoxysilane was mixed with a zirconium nitrate solution having a concentration of 0.50mol/L and stirred for 45 minutes to obtain a solution A in which the concentration of (3-mercaptopropyl) methyldimethoxysilane in the solution A was 0.19mol/L.

2) Slowly adding 3.4mol/L sodium hydroxide solution into the solution A to obtain a solution B, wherein the volume ratio of the sodium hydroxide solution to the solution A is 1:1.

3) And mixing the solution B with 7.6mol/L sodium silicate solution, heating in a water bath (60 ℃) and stirring until the solution is clear to obtain solution C, wherein the volume ratio of the sodium silicate solution to the solution B is 1:2.

4) Solution C was stirred in an oil bath under continuous reflux at 120deg.C for 2.0h until the solution became brown to give solution D.

5) Mixing the solution D with 7.1mol/L sodium metaaluminate solution, continuously stirring for 2 hours at room temperature, and standing for 8.5 hours until an off-white gel is formed, wherein the volume ratio of the sodium metaaluminate solution to the solution D is 1:3.

6) The off-white gel was transferred to an autoclave and reacted at 215℃for 11h.

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and stirringA stirring non-reactive machine. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then the reaction kettle is opened, a part of supernatant is taken by a disposable injector, and is filtered by filter paper, and the residual COD and TOC concentration in the sample is analyzed. The initial COD concentration of the wastewater was 154851mg/L and the TOC concentration was 149624mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

Fig. 11 shows that the removal of contaminants by the catalytic wet oxidation system is significantly increased over the wet oxidation system. The catalyst amount is 0.8g/L, and the removal rate of the wastewater by catalytic wet oxidation is about 33% higher than that by wet oxidation at the reaction temperature of 185 ℃ for 3.0 h.

Example 12

The catalyst prepared in the example 11 was used to treat high-concentration alkaline residue wastewater in a catalytic wet oxidation apparatus (GCF permanent magnet rotary stirring reactor), and the specific procedure was:

1500mL of alkaline residue wastewater is added into a 2.0L permanent magnet rotary stirring reaction kettle, a certain amount of catalyst is added for mixing, and the high-pressure reaction kettle is sealed to keep a certain oxygen partial pressure. And heating the reaction kettle to a set reaction temperature, and then carrying out a catalytic wet oxidation experiment of the alkaline residue wastewater. In the experimental process, a mechanical stirrer is adopted for stirring, and circulating water is utilized to protect electronic equipment for temperature control and non-reaction machinery for stirring. After the catalytic wet oxidation experiment is finished, cooling is carried out by cooling water to room temperature. Then the reaction kettle is opened, a part of supernatant is taken by a disposable injector, and is filtered by filter paper, and the residual COD and TOC concentration in the sample is analyzed. The initial COD concentration of the wastewater is 154851mg/L and the TOC concentration is 149624mg/L. COD removal Rate= (COD _{Before the reaction} -COD _{After the reaction} )÷COD _{Before the reaction} X 100%, TOC removal rate= (TOC) _{Before the reaction} -TOC _{After the reaction} )÷TOC _{Before the reaction} ×100％。

As seen from fig. 12, increasing the reaction temperature increases the removal rate of wastewater contaminants. Meanwhile, comparing the experimental results of fig. 11, increasing the amount of catalyst can also improve the pollutant removal effect. The reaction temperature is 200 ℃, the reaction time is 3.0h, and when the catalyst amount is 1.8g/L, the removal rates of COD and TOC of the catalytic wet oxidation system wastewater are respectively 98.86 percent and 96.67 percent.

In summary, as can be seen from fig. 13 to fig. 19, according to the preparation method of the nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst of the present invention, the properties of the catalyst are different due to different preparation processes. Fig. 13 shows that the catalysts obtained in example 1 and example 2 exhibit a mixture of nano-bulk and rod-like structures. Fig. 14 shows that the catalysts obtained in example 3 and example 4 still exhibit a mixture of nano-sized blocks and rod-like structures, but agglomeration occurred in a part of the regions. Fig. 15 shows that the catalysts obtained in example 5 and example 6 exhibit a nanorod-like structure, and that agglomeration phenomenon occurs in a part of the region. The catalysts obtained in examples 7 to 12 shown in fig. 16 to 18 exhibited good nanorod-like structures and were free from agglomeration.

The nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst is applied to the treatment of alkaline residue wastewater with high concentration in petrochemical industry, has stable catalytic effect, has a pollutant removal rate of more than 95%, and can effectively reduce the pollutant concentration of the wastewater and lighten the pollution and harm of the wastewater to the environment.

In the foregoing, the protection scope of the present invention is not limited to the preferred embodiments of the present invention, and any simple changes or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention disclosed in the present invention fall within the protection scope of the present invention.

Claims

1. The preparation method of the nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst is characterized by comprising the following steps of:

step 1, mixing and stirring 0.12-0.19mol/L (3-mercaptopropyl) methyldimethoxysilane and 0.1-0.5 mol/L nitrate solution for 45-60 minutes to obtain a solution A, wherein the nitrate solution is cerium nitrate solution or zirconium nitrate solution;

step 2, slowly adding a sodium hydroxide solution with the concentration of 1.5mol/L-3.5mol/L into the solution A to obtain a solution B, wherein the volume ratio of the sodium hydroxide solution to the solution A is 1:1;

step 3, mixing the solution B with a sodium silicate solution with the concentration of 6.1-7.6mol/L according to the volume ratio of 2:1, mixing, and heating in a water bath while stirring at 60-70 ℃ until the mixture is clear to obtain a solution C;

step 4, continuously condensing, refluxing, heating and stirring the solution C in an oil bath until the solution is brown to obtain a solution D, wherein the condensing, refluxing and heating temperature of the oil bath is 105-120 ℃ and the heating time is 1-2h;

step 5, mixing the solution D with the sodium metaaluminate solution, continuously stirring for 2-3 hours at room temperature, and standing until an off-white gel is formed, wherein the concentration of the sodium metaaluminate solution is 5.2-7.5mol/L, the standing time is 7-10 hours, and the volume ratio of the sodium metaaluminate solution to the solution D is 1:3;

step 6, transferring the off-white gel into a high-pressure reaction kettle to react for 10-12 hours at 180-220 ℃;

2. The nano zeolite coated heavy metal cluster catalytic material prepared based on the preparation method of the nano zeolite coated heavy metal cluster catalytic wet oxidation catalyst of claim 1.

3. The application of the nano zeolite coated heavy metal cluster catalytic material prepared according to the method in treating high-concentration organic wastewater is characterized in that the COD concentration of the high-concentration organic wastewater is 145000-155000mg/L petrochemical industry high-concentration alkaline residue wastewater.

4. The method according to claim 3, wherein the catalytic wet oxidation reaction is carried out at a temperature of 160-200 ℃ for a reaction time of 0.5-3.0h and the catalyst is added in an amount of 0.50-1.80g per liter of wastewater.