CN116371377B - A composite porous adsorption material for volatile organic compounds and a preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of adsorption materials, and specifically discloses a composite porous adsorption material for volatile organic compounds and a preparation method thereof. Under the action of a crosslinking agent, a diamine monomer and a dianhydride monomer are compounded with a doped porous carbon material to obtain a porous adsorption material, and erythritol is used as an auxiliary agent. Under the condition of 123-128°C, a nano material is infiltrated into the pores of the porous adsorption material by vacuum impregnation to obtain a composite porous adsorption material with a strong adsorption effect. The material has a high adsorption rate and a high adsorption amount for volatile organic compounds, and after a simple light treatment, the volatile organic compounds adsorbed inside the material can be catalytically degraded and almost no residue is left, so that when the material is reused for a second or even multiple times, the adsorption amount is hardly significantly reduced, and the material still has a high adsorption rate and a high adsorption amount, and has long-term and efficient reusability.

Description

A composite porous adsorption material for volatile organic compounds and its preparation method

Technical Field

The invention belongs to the technical field of adsorption materials, and in particular relates to a composite porous adsorption material for volatile organic compounds and a preparation method thereof.

Background technique

Volatile organic compounds (VOCs) are a general term for liquid or gaseous organic compounds that are easily volatilized into the atmosphere. Gaseous pollutants emitted by industries are the main source of atmospheric environmental pollutants. Among them, volatile organic compound waste gas is a gaseous pollutant that has a serious harmful effect on the environment. It is also the source of occupational disease hazards that affect the health of operators in the workplace. It is widely derived from chemical industries such as paint, coatings, coatings, lubricants, rubber, etc. Due to its huge destructive effect on the human body and the natural environment, the state has issued relevant laws and regulations to strictly control its management and emissions. The commonly used treatment methods for organic waste gas treatment technology currently include combustion, chemical oxidation, chemical absorption, adsorption, biological methods, etc. Among them, adsorption is a commonly used and effective method for organic waste gas purification. It is a method of adsorbing and purifying pollutants in the exhaust gas using various solid adsorbents (such as activated carbon, activated carbon fiber, molecular sieve, etc.); however, conventional adsorbents have limited adsorption efficiency and cannot show sufficient adsorption performance for VOC.

For example, Chinese patent CN104511273A discloses a method for preparing a volatile organic compound adsorption material, which uses a fiber-based material as a raw material, is activated by an oxidant, and an adsorption active substance is loaded onto the fiber-based material through a cross-linking reaction to prepare a crude adsorption material product, and the crude product is repeatedly washed with ethanol and distilled water to remove unreacted substances, and then dried to obtain a pure product volatile organic compound adsorption material; although the adsorption material has a good adsorption effect on volatile organic compounds, after the gas adsorption is saturated, it needs to be heated by high temperature or saturated steam before it can be used again, which is not only cumbersome to handle and easily causes waste of energy consumption, but also some of the adsorbed gases are not easy to desorb, so that the adsorption effect of the adsorption material will become worse and worse with the increase of the number of repeated uses, and it cannot meet the long-term repeated use.

Summary of the invention

In view of the problems existing in the prior art, the purpose of the present invention is to provide a composite porous adsorption material for volatile organic compounds. The adsorption material not only has a strong adsorption effect on volatile organic compounds, making it difficult for the adsorbed gas to desorb, but also has strong reusability. Its adsorption efficiency will not be affected by the number of repeated uses, and it has long-term and efficient reusability.

To achieve the above object, the present invention provides the following technical solutions:

A composite porous adsorption material for volatile organic compounds, wherein the composite porous adsorption material is prepared by the following method:

Under the action of a cross-linking agent, diamine monomers and dianhydride monomers are compounded with doped porous carbon materials to obtain a porous adsorption material. Erythritol is used as an auxiliary agent. At 123-128°C, manganese dioxide nanowires and titanium dioxide nanoparticles are infiltrated into the pores of the porous adsorption material by vacuum impregnation. Then, ultrasound is used to make the manganese dioxide nanowires clumped and the titanium dioxide nanoparticles locked in the pores, thereby obtaining a composite porous adsorption material with a strong adsorption effect.

As a further preferred embodiment of the present invention, the specific preparation method of the composite porous adsorption material is as follows:

(1) Add N-methylpyrrolidone and 4,4'-diaminodiphenyl ether to a container, stir until completely dissolved, slowly add pyromellitic anhydride to the mixed solution in portions, stir at 100-160 r/min in an ice water bath to allow sufficient reaction, then slowly dropwise add 3-aminopropyltriethoxysilane and continue stirring for 1-2 hours to obtain a reaction solution;

(2) pouring the reaction solution into a mold, adding the doped porous carbon material, stirring and dispersing it uniformly, adding acetic anhydride and pyridine at the same time, stirring thoroughly until the doped porous carbon material no longer settles, stopping stirring and aging for 25-30 hours, demolding it, eluting it with ethanol, and then drying it with supercritical carbon dioxide to obtain a porous adsorption material;

(3) fully mixing the manganese dioxide nanowires, titanium dioxide nanoparticles, and erythritol, heating them to 123-128° C., and uniformly dispersing them by ultrasonication to obtain an impregnation solution; placing the porous adsorption material in a vacuum impregnation tank, evacuating the tank to reduce the vacuum degree in the tank to below 10 Pa, and then injecting nitrogen into the vacuum impregnation tank to make the air pressure in the tank reach one atmosphere, controlling the temperature in the tank at 123-128° C., evacuating the tank again to reduce the vacuum degree in the tank to below 10 Pa, and then injecting a sufficient amount of impregnation solution into the tank, and impregnating for 8-12 hours;

(4) After the impregnation is completed, the product together with the excess impregnation liquid is transferred to a container and ultrasonically treated at 113-116°C for 1-2 hours. After the treatment is completed, the product is heated to 123-128°C and ultrasonically treated for 3-5 hours. The product is then taken out and placed in an oven at 125-130°C for drying for 10-15 hours to obtain a composite porous adsorption material.

Furthermore, the ratio of N-methylpyrrolidone, 4,4'-diaminodiphenyl ether, pyromellitic acid dianhydride, and 3-aminopropyltriethoxysilane in step (1) is 22-25 mL: 1.0-1.6 g: 2.0-2.8 g: 2.2-2.5 g;

Furthermore, the doped porous carbon material in step (2) is prepared by the following method: ethylenediamine, carbon tetrachloride and white carbon black are placed in a container, and after sufficient stirring, the container is connected to a condensation reflux device, placed in a 90-95°C oil bath, heated and stirred for 6-10 hours, and after the reaction is completed, the product is taken out and dried, and then calcined at 600-650°C for 4-6 hours under a nitrogen atmosphere. The obtained product is ground and immersed in 5-8wt% hydrofluoric acid and immersed and stirred for 24-30 hours, filtered, washed, dried, and ultrafinely ground to obtain a doped porous carbon material; wherein the ratio of ethylenediamine, carbon tetrachloride and white carbon black is 5-10mL:5-10mL:1-3g.

Furthermore, the amount of the doped porous carbon material added in step (2) accounts for 10-15% of the weight of the reaction solution;

Furthermore, the ratio of the reaction solution, acetic anhydride and pyridine in step (2) is 25-30 mL: 8.0-8.5 g: 21-23 g;

Furthermore, the ethanol displacement elution in step (2) is performed 3-5 times, and the displacement time is 10-13h/time.

Furthermore, in step (3), the mass ratio of the manganese dioxide nanowires, titanium dioxide nanoparticles and erythritol is 3-8:1-5:30-50;

Furthermore, the power of the ultrasonic dispersion in step (3) is 200-300W.

Furthermore, the power of the ultrasonic treatment in step (4) is 800-1000W.

The present invention also provides a method for preparing manganese dioxide nanowires: after dissolving manganese sulfate, potassium chlorate and potassium acetate in deionized water, adding acetic acid solution and stirring for 5-10 minutes, then transferring the formed mixed solution into a reaction kettle, sealing it and placing it in an oven at 160-170° C. to react for 12-15 hours, cooling it to room temperature after the reaction is completed, washing the product and drying it to obtain manganese dioxide nanowires.

Preferably, the ratio of manganese sulfate, potassium chlorate, potassium acetate, deionized water and acetic acid solution is 6.2-7.3 g: 8.5-9.6 g: 6.5-7.0 g: 60-80 mL: 30-37 mL.

The concentration of the acetic acid solution is 3-5wt%.

Compared with the prior art, the present invention has the following beneficial effects:

In the present invention, ethylenediamine and carbon tetrachloride are used as nitrogen source and carbon source, and white carbon black is used as hard template to synthesize nitrogen-doped porous carbon material. By doping the porous carbon material, on the one hand, the porosity of the porous carbon material can be effectively improved, so that it has a better specific surface area, and at the same time, the pore volume of the porous carbon material is increased, so that it has a larger spatial position, which can provide sufficient accommodation space for the adsorbed volatile organic compounds, thereby having a larger adsorption capacity; moreover, nitrogen atoms are doped into the carbon material skeleton, which will produce a large number of defect sites, and the formation of these defect sites is more conducive to the formation of a large number of active centers in the carbon material, so that the carbon material can be quickly adsorbed. The volatile organic compounds from the outside are adsorbed and confined in the pores, which can significantly improve the adsorption firmness, thereby reducing the desorption of the adsorbed volatile compounds; at the same time, the mesoporous structure that penetrates the inside of the doped porous carbon material is conducive to the transmission and diffusion of volatile organic compounds, which can greatly improve the adsorption performance, and with the increase of the specific surface area of the doped porous carbon material, the contact area between the volatile organic compounds and the active sites is also increased, which has a positive effect on the adsorption and mass transfer process, and can significantly improve the adsorption rate, so that the doped porous carbon material can form a high adsorption rate and high adsorption amount for volatile organic compounds.

In the present invention, 4,4'-diaminodiphenyl ether is selected as a diamine monomer, pyromellitic dianhydride is selected as a dianhydride monomer, and under the action of a cross-linking agent 3-aminopropyltriethoxysilane, they are compounded with a doped porous carbon material to form a porous adsorption material, and erythritol is used as an auxiliary agent. Taking advantage of the fact that erythritol has the characteristic of changing physical properties with temperature, at 123-128°C, liquid erythritol is used as an auxiliary agent, and a vacuum impregnation method is used to inject manganese dioxide nanowires and nano-titanium dioxide into the pores of the porous adsorption material, and the temperature is reduced to 113-116°C by regulating the temperature, so that the erythritol is in a viscous state close to melting and does not flow out of the pores, and through ultrasonic action, the manganese dioxide nanowires and nano-titanium dioxide infiltrated into the porous adsorption material are in a viscous state. Violent movement occurs in erythritol. During the violent movement, manganese dioxide nanowires will entangle with each other to form a network structure and block the pores of the porous adsorption material, thereby confining nano titanium dioxide in the pores of the porous material. At the same time, it will not affect the entry of external volatile organic compounds into the pores. The infiltrated nano titanium dioxide can catalytically degrade volatile organic compounds under the action of light, so that the adsorption saturated composite porous adsorption material can be reused. Moreover, since the volatile organic compounds adsorbed in the composite porous adsorption material are catalytically degraded under light conditions instead of desorbed, there will be almost no residual volatile organic compounds in the composite porous adsorption material when it is reused, so that its adsorption amount will hardly decrease significantly when it is reused for the second or even multiple times.

The composite porous adsorption material provided in the present invention has a high adsorption rate and a high adsorption amount for volatile organic compounds, and after a simple light treatment, the volatile organic compounds adsorbed inside can be catalytically degraded with almost no residue, so that when the composite porous adsorption material is reused for a second or even multiple times, its adsorption amount will hardly decrease significantly, and it still has a high adsorption rate and a high adsorption amount, and has long-term and efficient reusability.

Detailed ways

The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Example 1

A composite porous adsorption material for volatile organic compounds, the preparation method of the composite porous adsorption material is as follows:

S1, under the action of a crosslinking agent, compounding a diamine monomer and a dianhydride monomer with a doped porous carbon material to prepare a porous adsorption material, specifically comprising the following steps:

1) 5 mL of ethylenediamine, 5 mL of carbon tetrachloride and 1 g of white carbon black are placed in a container, and after being fully stirred, the container is connected to a condensation reflux device, placed in a 90°C oil bath, heated and stirred for 6 hours, and after the reaction is completed, the product is taken out and placed in an evaporating dish, heated and dried at 80°C, and then moved to a 600°C tube furnace under the protection of a nitrogen atmosphere for calcination for 4 hours. The obtained product is ground and immersed in 5wt% hydrofluoric acid and immersed and stirred for 24 hours, filtered, and then repeatedly washed with ethanol, placed in a 100°C oven for full drying, and then ultrafinely ground to obtain a doped porous carbon material;

2) Add 22 mL of N-methylpyrrolidone and 1 g of 4,4'-diaminodiphenyl ether to a container, stir until completely dissolved, slowly add a total of 2 g of pyromellitic anhydride to the mixed solution in three portions, stir at 100 r/min for 3 h in an ice-water bath, then slowly dropwise add 2.2 g of 3-aminopropyltriethoxysilane and continue stirring for 1 h to obtain a reaction solution;

3) Pour 25 mL of the reaction solution into a mold, add 10% of the weight of the doped porous carbon material, stir and disperse evenly, then add 8 g of acetic anhydride and 21 g of pyridine, stir thoroughly until the doped porous carbon material no longer settles, stop stirring and age for 25 h, demould it, soak it in an ethanol solution for replacement 3 times, the replacement time is 10 h/time, and then dry it with supercritical carbon dioxide to obtain a porous adsorption material;

S2 uses erythritol as an auxiliary agent, and uses vacuum impregnation at 123°C to infiltrate the nanomaterial into the pores of the porous adsorption material, thereby obtaining a composite porous adsorption material with a strong adsorption effect; specifically, the steps include:

1) After dissolving 6.2 g of manganese sulfate, 8.5 g of potassium chlorate and 6.5 g of potassium acetate in 60 mL of deionized water, 30 mL of 3 wt% acetic acid solution was added and stirred at 80 r/min for 5 min, and then the resulting mixed solution was transferred to a reactor, sealed and placed in an oven at 160° C. for reaction for 12 h, and after the reaction was completed, cooled to room temperature, and the product was repeatedly washed with deionized water and ethanol alternately and then dried to obtain manganese dioxide nanowires;

2) 3 g of manganese dioxide nanowires and 1 g of nano-titanium dioxide are fully mixed and added to a container, 30 g of erythritol is added, mixed evenly, heated to 123° C. and ultrasonically dispersed at 200 W for 10 min to obtain an impregnation solution, the porous adsorption material is placed in a vacuum impregnation tank, evacuated, the vacuum degree in the tank is reduced to below 10 Pa, nitrogen is then injected into the vacuum impregnation tank to make the air pressure in the tank reach one atmosphere, the temperature in the tank is controlled at 123° C., evacuated again to reduce the vacuum degree in the tank to below 10 Pa, and then a sufficient amount of impregnation solution is injected into the tank for immersion for 8 hours;

3) After the impregnation is completed, the product is transferred to a container together with the excess impregnation liquid, and the temperature of the container is controlled at 113°C. Under the action of 800W ultrasound, the ultrasonic treatment is carried out for 1 hour. After the treatment is completed, it is heated to 123°C and the ultrasonic treatment is continued for 3 hours. Then the product is taken out and placed in an oven, and dried at 125°C for 10 hours to obtain a composite porous adsorption material.

Example 2

A composite porous adsorption material for volatile organic compounds, the preparation method of the composite porous adsorption material is as follows:

S1, under the action of a crosslinking agent, compounding a diamine monomer and a dianhydride monomer with a doped porous carbon material to prepare a porous adsorption material, specifically comprising the following steps:

1) 8 mL of ethylenediamine, 8 mL of carbon tetrachloride and 2 g of white carbon black were placed in a container, and after being fully stirred, the container was connected to a condensation reflux device, placed in a 92°C oil bath, heated and stirred for 8 h, and after the reaction was completed, the product was taken out and placed in an evaporating dish, heated and dried at 83°C, and then moved to a 620°C tubular furnace under the protection of a nitrogen atmosphere for calcination for 5 h. The obtained product was ground and immersed in 7 wt% hydrofluoric acid and immersed and stirred for 28 h, filtered, and then washed repeatedly with ethanol, placed in a 110°C oven for full drying, and then ultrafinely ground to obtain a doped porous carbon material;

2) Add 23 mL of N-methylpyrrolidone and 1.2 g of 4,4'-diaminodiphenyl ether to a container, stir until completely dissolved, slowly add a total of 2.5 g of pyromellitic anhydride to the mixed solution in 4 portions, stir at 140 r/min for 4 h in an ice-water bath, then slowly dropwise add 2.3 g of 3-aminopropyltriethoxysilane and continue stirring for 1.5 h to obtain a reaction solution;

3) Pour 28 mL of the reaction solution into a mold, add 13% of the weight of the doped porous carbon material, stir and disperse evenly, then add 8.3 g of acetic anhydride and 22 g of pyridine, stir thoroughly until the doped porous carbon material no longer settles, stop stirring and let stand for aging for 28 h, demould it, soak it in an ethanol solution for 4 times, the replacement time is 12 h/time, and then dry it with supercritical carbon dioxide to obtain a porous adsorption material;

S2 uses erythritol as an auxiliary agent, and uses vacuum impregnation at 125°C to infiltrate the nanomaterial into the pores of the porous adsorption material, thereby obtaining a composite porous adsorption material with a strong adsorption effect; specifically, the steps include:

1) After dissolving 6.8 g of manganese sulfate, 9.2 g of potassium chlorate and 6.7 g of potassium acetate in 70 mL of deionized water, 35 mL of 4 wt% acetic acid solution was added and stirred at 110 r/min for 6 min, and then the resulting mixed solution was transferred to a reactor, sealed and placed in an oven at 165° C. for reaction for 13 h, and after the reaction was completed, cooled to room temperature, and the product was repeatedly washed with deionized water and ethanol alternately and then dried to obtain manganese dioxide nanowires;

2) 5 g of manganese dioxide nanowires and 3 g of nano-titanium dioxide were fully mixed and added to a container, 40 g of erythritol was added, the mixture was heated to 125° C. and ultrasonically dispersed at 250 W for 15 min to obtain an impregnation solution, the porous adsorption material was placed in a vacuum impregnation tank, vacuumed, the vacuum degree in the tank was reduced to below 10 Pa, nitrogen was then injected into the vacuum impregnation tank to make the air pressure in the tank reach one atmosphere, the temperature in the tank was controlled at 125° C., vacuumed again to reduce the vacuum degree in the tank to below 10 Pa, and then a sufficient amount of impregnation solution was injected into the tank for impregnation for 10 hours;

3) After the impregnation is completed, the product is transferred to a container together with the excess impregnation liquid, and the temperature of the container is controlled at 115°C. Under the action of 900W ultrasound, the ultrasonic treatment is carried out for 1.5 hours. After the treatment is completed, it is heated to 125°C and the ultrasonic treatment is continued for 4 hours. Then the product is taken out and placed in an oven and dried at 128°C for 13 hours to obtain a composite porous adsorption material.

Example 3

A composite porous adsorption material for volatile organic compounds, the preparation method of the composite porous adsorption material is as follows:

S1, under the action of a crosslinking agent, compounding a diamine monomer and a dianhydride monomer with a doped porous carbon material to prepare a porous adsorption material, specifically comprising the following steps:

1) 10 mL of ethylenediamine, 10 mL of carbon tetrachloride and 3 g of white carbon black were placed in a container, and after being fully stirred, the container was connected to a condensation reflux device, placed in a 95°C oil bath, heated and stirred for 10 hours, and after the reaction was completed, the product was taken out and placed in an evaporating dish, heated and dried at 85°C, and then moved to a 650°C tubular furnace under the protection of a nitrogen atmosphere for calcination for 6 hours. The obtained product was ground and immersed in 8wt% hydrofluoric acid and immersed and stirred for 30 hours, filtered, and then washed repeatedly with ethanol, placed in a 120°C oven for full drying, and then ultrafinely ground to obtain a doped porous carbon material;

2) Add 25 mL of N-methylpyrrolidone and 1.6 g of 4,4'-diaminodiphenyl ether to a container, stir until completely dissolved, slowly add a total of 2.8 g of pyromellitic anhydride to the mixed solution in 5 portions, stir at 160 r/min for 5 h in an ice-water bath, then slowly dropwise add 2.5 g of 3-aminopropyltriethoxysilane and continue stirring for 2 h to obtain a reaction solution;

3) Pour 30 mL of the reaction solution into a mold, add 15% of the weight of the doped porous carbon material, stir and disperse evenly, then add 8.5 g of acetic anhydride and 23 g of pyridine, stir thoroughly until the doped porous carbon material no longer settles, stop stirring and age for 30 h, demould it, soak it in an ethanol solution and replace it 5 times, the replacement time is 13 h/time, and then dry it with supercritical carbon dioxide to obtain a porous adsorption material;

S2 uses erythritol as an auxiliary agent, and uses vacuum impregnation at 128°C to infiltrate the nanomaterial into the pores of the porous adsorption material, thereby obtaining a composite porous adsorption material with a strong adsorption effect; specifically, the steps include:

1) After dissolving 7.3 g of manganese sulfate, 9.6 g of potassium chlorate and 7.0 g of potassium acetate in 80 mL of deionized water, 37 mL of 5 wt% acetic acid solution was added and stirred at 130 r/min for 10 min, and then the resulting mixed solution was transferred to a reactor, sealed and placed in an oven at 170° C. for reaction for 15 h, cooled to room temperature after the reaction was completed, and the product was washed alternately with deionized water and ethanol and then dried to obtain manganese dioxide nanowires;

2) 8 g of manganese dioxide nanowires and 5 g of nano-titanium dioxide were fully mixed and added to a container, 50 g of erythritol was added, the mixture was heated to 128° C. and ultrasonically dispersed at 300 W for 20 min to obtain an impregnation solution, the porous adsorption material was placed in a vacuum impregnation tank, vacuumed, the vacuum degree in the tank was reduced to below 10 Pa, nitrogen was then injected into the vacuum impregnation tank to make the air pressure in the tank reach one atmosphere, the temperature in the tank was controlled at 128° C., vacuumed again to reduce the vacuum degree in the tank to below 10 Pa, and then a sufficient amount of impregnation solution was injected into the tank for impregnation for 12 hours;

3) After the impregnation is completed, the product is transferred to a container together with the excess impregnation liquid, and the temperature of the container is controlled at 116°C. Under the action of 1000W ultrasound, the ultrasonic treatment is carried out for 2 hours. After the treatment is completed, it is heated to 128°C and the ultrasonic treatment is continued for 5 hours. Then the product is taken out and placed in an oven, and dried at 130°C for 15 hours to obtain a composite porous adsorption material.

Comparative Example 1

This comparative example is substantially the same as Example 1, except that activated carbon is used instead of the doped porous carbon material.

Comparative Example 2

This comparative example is substantially the same as Example 1, except that deionized water is used instead of erythritol in the preparation of the composite porous adsorption material.

Comparative Example 3

This comparative example is substantially the same as Example 1, except that manganese dioxide nanowires are not added in the preparation of the composite porous adsorption material.

Comparative Example 4

This comparative example is basically the same as Example 1, except that nano titanium dioxide is not added in the preparation of the composite porous adsorption material.

According to the "Technical Specifications for Monitoring Exhaust Gas from Stationary Sources" (HJ/T397-2007) and the "Determination of Volatile Organic Compounds in Exhaust Gas from Stationary Pollution Sources by Solid Phase Adsorption-Thermal Desorption/Gas Chromatography-Mass Spectrometry" (HJ734-2014), the VOCs of the exhaust pipe pollutants in the loader painting workshop of Hangzhou Minsheng Machinery Manufacturing Co., Ltd. were detected respectively. The dosage of the composite porous adsorption material samples provided in Examples 1-3 and Comparative Examples 1-4 was 50 kg. The results are shown in Table 1.

The composite porous adsorption material sample used for more than 170 hours was placed under light for 10 hours and then reused a second time to test the adsorption performance of the reused composite porous adsorption material sample. The results are shown in Table 1.

Table 1: Performance test results of the composite porous adsorbent samples of Examples 1-3 and Comparative Examples 1-4 for the first and second use

It can be seen from Table 1 that the composite porous adsorption material of the present invention has a strong adsorption effect on volatile organic compounds, and the effect is still significant when it is reused for the second time, and it has long-term and efficient reusability.

The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims (8)

1. A composite porous adsorption material, characterized in that a diamine monomer and a dianhydride monomer are compounded with a doped porous carbon material under the action of a crosslinking agent to obtain a porous adsorption material; erythritol is used as an auxiliary agent, and manganese dioxide nanowires and titanium dioxide nanoparticles are infiltrated into the pores of the porous adsorption material by vacuum impregnation at 123-128° C., and then the manganese dioxide nanowires are agglomerated and the titanium dioxide nanoparticles are locked in the pores by ultrasound to obtain the composite porous adsorption material; The preparation method of the doped porous carbon material comprises the following steps: putting ethylenediamine, carbon tetrachloride and white carbon black into a container, fully stirring the container, connecting the container to a condensation reflux device, putting the container into a 90-95° C. oil bath, heating and stirring for 6-10 hours, taking out the product after drying, and calcining it at 600-650° C. under nitrogen atmosphere for 4-6 hours after the reaction is completed, grinding the obtained product, soaking it in 5-8wt% hydrofluoric acid, soaking it and stirring it for 24-30 hours, filtering, washing, drying it, and ultrafine grinding it to obtain the doped porous carbon material; wherein the ratio of ethylenediamine, carbon tetrachloride and white carbon black is 5-10mL:5-10mL:1-3g. 2. The method for preparing the composite porous adsorbent material according to claim 1, characterized in that it comprises the following steps: (1) Add N-methylpyrrolidone and 4,4 ^- diaminodiphenyl ether to a container, stir until completely dissolved, then slowly add pyromellitic anhydride in portions, stir at 100-160r/min in an ice water bath to allow for sufficient reaction, then slowly dropwise add 3-aminopropyltriethoxysilane and continue stirring for 1-2h to obtain a reaction solution; wherein the ratio of N-methylpyrrolidone, 4,4 ^- diaminodiphenyl ether, pyromellitic anhydride, and 3-aminopropyltriethoxysilane is 22-25mL: 1.0-1.6g: 2.0-2.8g: 2.2-2.5g; (2) Pour the reaction solution into a mold, add the doped porous carbon material, stir and disperse evenly, then add acetic anhydride and pyridine, stir thoroughly until the doped porous carbon material no longer settles, stop stirring and age for 25-30 hours, demold, wash with ethanol, and dry with carbon dioxide supercritically to obtain a porous adsorption material; wherein the ratio of the reaction solution, acetic anhydride, and pyridine is 25-30 mL: 8.0-8.5 g: 21-23 g; (3) After fully mixing the manganese dioxide nanowires, titanium dioxide nanoparticles and erythritol, heat them to 123-128°C and disperse them evenly by ultrasonication to obtain an impregnation solution; place the porous adsorption material in a vacuum impregnation tank, reduce the vacuum degree in the tank to below 10Pa, inject nitrogen into the vacuum impregnation tank to make the air pressure in the tank reach one atmosphere, control the temperature in the tank at 123-128°C, evacuate the tank again to reduce the vacuum degree in the tank to below 10Pa, and then inject the impregnation solution into the tank for impregnation for 8-12 hours; (4) After the impregnation is completed, the product together with the excess impregnation liquid is transferred to a container and ultrasonically treated at 113-116°C for 1-2 hours. After the treatment is completed, the product is heated to 123-128°C and ultrasonically treated for 3-5 hours. The product is dried at 125-130°C for 10-15 hours to obtain a composite porous adsorption material. 3. The method for preparing a composite porous adsorption material according to claim 2, characterized in that the amount of the doped porous carbon material added accounts for 10-15% of the weight of the reaction solution. 4. The method for preparing a composite porous adsorbent material according to claim 2, characterized in that the ethanol displacement elution is performed 3 to 5 times, and the displacement time is 10-13 hours per time. 5. The method for preparing a composite porous adsorption material according to claim 2, characterized in that in the impregnation solution, the mass ratio of manganese dioxide nanowires, nano-titanium dioxide and erythritol is 3-8:1-5:30-50. 6. The method for preparing a composite porous adsorbent material according to claim 2, characterized in that the power of the ultrasonic treatment in step (4) is 800-1000W. 7. The method for preparing a composite porous adsorption material according to claim 2, characterized in that the manganese dioxide nanowires are prepared by the following method: after dissolving manganese sulfate, potassium chlorate and potassium acetate in deionized water, 3-5wt% acetic acid solution is added and stirred for 5-10 minutes, and then the formed mixed solution is transferred to a reactor, sealed and placed in an oven at 160-170°C for reaction for 12-15 hours, and after the reaction is completed, it is cooled to room temperature, the product is washed and dried to obtain manganese dioxide nanowires. 8. The method for preparing a composite porous adsorbent material according to claim 7, characterized in that the ratio of manganese sulfate, potassium chlorate, potassium acetate, deionized water and acetic acid solution is 6.2-7.3 g: 8.5-9.6 g: 6.5-7.0 g: 60-80 mL: 30-37 mL.