An absorbent for treating organic waste gas and its preparation method

Abstract

This invention belongs to the field of waste gas treatment technology, specifically relating to an absorbent for treating organic waste gas and its preparation method. The absorbent for treating organic waste gas comprises the following raw materials in parts by weight: 10-25 parts graphene oxide, 20-30 parts catalyst, 25-40 parts functionalized ionic liquid, and 10-20 parts N-isopropylacrylamide. In the catalyst prepared by this invention, the synergistic effect of the cerium source, cobalt source, and sodium selenate forms a stable heterojunction structure through hydrothermal and thermal treatment processes, optimizing the number and distribution of catalytic active sites and enhancing catalytic oxidation capacity. After oxidation and modification, the graphene oxide enhances its dispersion stability, firmly anchoring the catalyst particles to the graphene surface and accelerating electron transfer in the catalytic reaction. This results in the prepared absorbent for treating organic waste gas possessing high adsorption capacity, efficient catalytic degradation ability, and cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of waste gas treatment technology, specifically relating to an absorbent for treating organic waste gas and its preparation method. Background Technology

[0002] With the rapid development of industry, organic waste gases emitted by industries such as coating, printing, petrochemicals, and pharmaceuticals have become a significant source of air pollution. These waste gases are complex in composition, containing various pollutants such as aromatic hydrocarbons, aldehydes, ketones, esters, and sulfur- and nitrogen-containing impurities. They are characterized by high toxicity, wide diffusion range, and high treatment difficulty, not only harming human health but also causing environmental problems such as photochemical smog. Therefore, the efficient treatment of organic waste gases is urgently needed.

[0003] Currently, adsorption is widely used in organic waste gas treatment due to its simplicity and low cost. However, traditional adsorption materials can only physically enrich pollutants and cannot completely degrade them, easily causing secondary pollution. While catalytic oxidation can completely mineralize organic waste gas, it suffers from drawbacks such as high catalyst ignition temperature, low efficiency in treating low-concentration waste gas, and susceptibility to poisoning and deactivation by sulfur- and nitrogen-containing impurities. To integrate the advantages of both technologies, integrated adsorption-catalysis materials have become a research hotspot. However, existing integrated materials still have many shortcomings: some materials only combine adsorbent and catalyst through simple physical mixing, resulting in weak interfacial bonding and preventing synergistic adsorption and catalytic performance; adsorption capacity and catalytic activity decay rapidly, and cycle stability is poor. Therefore, developing a material that combines high adsorption capacity, excellent anti-poisoning performance, and cycle stability is of great significance for advancing organic waste gas treatment technology. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an absorbent for treating organic waste gas and its preparation method.

[0005] This invention prepares a composite system of a catalyst, amino-functionalized graphene oxide, and temperature-sensitive ionic liquid microcapsules, employing a stepwise controllable preparation strategy to obtain the target absorbent. The graphene oxide in this invention, after oxidation and modification, enhances its dispersion stability, firmly anchoring the catalyst particles to the graphene surface and accelerating electron transfer in the catalytic reaction. This solves the technical problems of existing organic waste gas treatment materials, such as the inability to synergistically utilize adsorption and catalytic performance, susceptibility to poisoning and deactivation by impurities, poor cycle stability, and difficulty in adapting to complex operating conditions. The prepared absorbent for organic waste gas treatment possesses high adsorption capacity, efficient catalytic degradation capability, and cycle stability, enabling efficient treatment of various organic waste gases. Furthermore, the preparation process is controllable and reproducible, adaptable to complex operating conditions in multiple industries such as coating, printing, and petrochemicals, demonstrating significant application value.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides an absorbent for treating organic waste gas, the absorbent comprising the following raw materials in parts by weight: 10-25 parts graphene oxide, 20-30 parts catalyst, 25-40 parts functionalized ionic liquid, 10-20 parts N-isopropylacrylamide, 5-10 parts 4-dimethylaminopyridine, and 15-25 parts DCC.

[0008] The catalyst comprises raw materials in the following mass ratio: Ce(NO3)3·6H2O:Co(NO3)2·6H2O:sodium selenate:urea:PVP (polyvinylpyrrolidone) = 1-1.5:0.9:0.6:1.2:0.1;

[0009] The method for preparing the catalyst includes the following steps:

[0010] (1) Weigh Ce(NO3)3·6H2O and cobalt nitrate hexahydrate, add ethylene glycol, place the beaker in a 60℃ constant temperature water bath to form solution A, weigh sodium selenate and dissolve it in deionized water, and after complete dissolution, form solution B; add PVP and urea to solution A in sequence to obtain a mixture, sonicate the mixture for 10 minutes, and under continuous magnetic stirring, slowly and dropwise add solution B to the mixture using a constant pressure dropping funnel to form a mixture;

[0011] (2) Slowly add 25% ammonia water to the mixture until the pH value of the system stabilizes at 9-10 and a sol is formed. Transfer all the sol to a high-pressure reactor with a polytetrafluoroethylene liner and carry out hydrothermal reaction according to the following procedure: raise the temperature from room temperature to 120°C at a rate of 2°C / min and keep it at 120°C for 8 hours. Then raise the temperature to 180°C at a rate of 1°C / min and keep it at 180°C for 20 hours. After the reaction is completed, turn off the oven power and let the reactor cool naturally to room temperature in the oven. Centrifuge for 10 min, discard the supernatant, wash, and dry for 6 hours to obtain the precursor powder.

[0012] (3) The dried precursor powder was heat-treated according to the following procedure: the furnace temperature was increased from room temperature to 350°C at a heating rate of 2°C / min, and held at this temperature for 2 hours. Then the temperature was increased to 450°C at a rate of 5°C / min, and held at this temperature for 2 hours. After the heat treatment was completed, the powder was cooled naturally, and then gently ground with an agate mortar and passed through a 400-mesh standard sieve to obtain the catalyst.

[0013] This invention also provides a method for preparing an absorbent for treating organic waste gas, specifically including the following steps:

[0014] S1, weigh graphene oxide and add it to a freshly prepared mixed acid solution made of concentrated sulfuric acid and concentrated nitric acid at a volume ratio of 3:1 (graphene oxide to mixed acid solution ratio 1 mg: 1 mL). Place in an ice-water bath and sonicate for 3 hours. After treatment, dilute and then filter under reduced pressure. Wash with deionized water until pH is neutral. Redisperse the obtained product in anhydrous N,N-dimethylformamide (DMF) to form a graphene dispersion with a concentration of 1.5-3 mg / mL. KH-550 and 4-dimethylaminopyridine were added to the graphene dispersion. The mixture was heated to 80°C under nitrogen protection and stirred under reflux for 24 hours. After the reaction was completed, N,N′-dicyclohexylcarbodiimide (DCC) was added, wherein the volume ratio of graphene dispersion to KH-550 was 50:1. The reaction was continued at 80°C for 12 hours. The mixture was then centrifuged and washed, and the resulting product was redispersed in anhydrous ethanol to obtain a stable aminated graphene dispersion.

[0015] S2, weigh the catalyst, add anhydrous ethanol, the ratio of catalyst to anhydrous ethanol is 1g:25mL, sonicate for 30 minutes to fully disperse it to obtain a suspension, mix the suspension with the amino graphene dispersion, add glacial acetic acid, stir and react for 8 hours, after the reaction is completed, collect the solid product by centrifugation, wash, and finally dry to constant weight in a vacuum drying oven at 60℃ to obtain composite powder.

[0016] S3, N-isopropylacrylamide, N,N′-methylenebisacrylamide (MBA) and benzoyl peroxide (initiator BPO) are added to the functionalized ionic liquid, wherein the mass ratio of N-isopropylacrylamide, MBA and initiator BPO is 5:0.5:0.1, tetrahydrofuran is added to dissolve, and the mixture is refluxed at 70°C for 6 hours. The solvent is removed by rotary evaporation to obtain a thermosensitive ionic liquid prepolymer.

[0017] S4. The thermosensitive ionic liquid prepolymer is dissolved in cyclohexane and sonicated to completely dissolve it, forming an oil phase. The ratio of thermosensitive ionic liquid prepolymer to cyclohexane is 0.5g:20mL. The composite powder is weighed and added to deionized water containing sodium dodecyl sulfate (SDS). The ratio of composite powder to deionized water is 0.1g:50mL. The mixture is vigorously stirred and sonicated for 30 minutes to form an aqueous phase. In a high-speed shear disperser, the oil phase is slowly poured into the aqueous phase and emulsified by high-speed shearing for 5 minutes to form a stable oil-in-water emulsion. Potassium persulfate is added to the emulsion. The ratio of emulsion to potassium persulfate is 15-20mL:1mg. The mixture is transferred to a 70℃ water bath and stirred at 300rpm for 6 hours to complete interfacial polymerization. The mixture is then filtered, washed, and dried for 12 hours to obtain an absorbent for treating organic waste gas.

[0018] Further, the preparation process of the functionalized ionic liquid is as follows: 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and dry dichloromethane are weighed, and acryloyl chloride is slowly added dropwise using a constant pressure dropping funnel under ice-water bath and stirring. The ratio of 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, dichloromethane and acryloyl chloride is 1g:40-60mL:0.5mL. The dropping time is controlled to exceed 30 minutes. After the dropping is completed, the ice bath is removed, and the reaction is stirred at room temperature for 12 hours. After the reaction is completed, dichloromethane is removed using a rotary evaporator to obtain the functionalized ionic liquid.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0020] The interactions among the raw materials in this invention significantly enhance the overall performance of the absorbent. The synergistic effect of the cerium source, cobalt source, and sodium selenate in the catalyst prepared by this invention, through hydrothermal and thermal treatment processes, forms a stable heterojunction structure. This not only optimizes the number and distribution of catalytic active sites but also strengthens the catalytic oxidation capacity through the electron transfer effect at the heterojunction interface, providing the core driving force for the efficient degradation of organic waste gas. The introduction of PVP and urea improves the dispersibility and structural stability of the catalyst by dispersing and regulating the crystallization process, preventing the agglomeration and deactivation of active sites. After mixed acid oxidation and KH-550 amination modification, the carboxyl and amino groups on the surface of graphene oxide not only enhance its own dispersion stability but also form a strong interfacial interaction with the catalyst, firmly anchoring the catalyst particles to the graphene surface. This inhibits the agglomeration and growth of catalyst particles and accelerates electron transfer in the catalytic reaction through the excellent electron transport properties of graphene. Simultaneously, the layered structure of graphene provides abundant adsorption channels and sites for organic waste gas molecules, achieving a synergistic improvement in adsorption and catalytic performance. A thermosensitive ionic liquid prepolymer, formed by the polymerization reaction of 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt with N-isopropylacrylamide after acrylate functionalization, uniformly coats the surface of the composite powder to form a microcapsule structure during interfacial polymerization. The stepwise composite and interfacial fusion of the raw materials during the preparation process endows the absorbent with high adsorption capacity, efficient catalytic degradation ability, excellent anti-poisoning performance, and cycle stability, providing reliable material support for the treatment of organic waste gas under complex operating conditions. Attached Figure Description

[0021] Figure 1 Here is a SEM image of the catalyst prepared in this invention;

[0022] Figure 2 This is a cyclic stability diagram of the absorbent prepared in this invention for treating organic waste gas. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions of the present invention and to make the above-mentioned features, objectives, and advantages of the present invention clearer and easier to understand, the present invention will be further described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0025] Unless otherwise specified, all methods described in the following embodiments are conventional. Unless otherwise specified, all materials used in the following embodiments are new materials purchased from the market.

[0026] Example 1: This example provides an absorbent for treating organic waste gas, which comprises the following raw materials in parts by weight: 10 parts graphene oxide, 20 parts catalyst, 25 parts functionalized ionic liquid, 10 parts N-isopropylacrylamide, 5 parts 4-dimethylaminopyridine, and 15 parts DCC.

[0027] The catalyst comprises raw materials in the following mass ratio: Ce(NO3)3·6H2O:Co(NO3)2·6H2O:sodium selenate:urea:PVP=1:0.9:0.6:1.2:0.1;

[0028] The method for preparing the catalyst includes the following steps:

[0029] (1) Weigh Ce(NO3)3·6H2O and cobalt nitrate hexahydrate, add ethylene glycol, the ratio of Ce(NO3)3·6H2O to ethylene glycol is 1g:40mL, place in a 60℃ constant temperature water bath, dissolve under magnetic stirring to form solution A, weigh sodium selenate and dissolve in deionized water, the ratio of sodium selenate to deionized water is 0.3g:10mL, after complete dissolution to form solution B, add PVP and urea to solution A in sequence to obtain a mixture, sonicate the mixture for 10 minutes to ensure that the additives are fully dispersed, under continuous magnetic stirring, use a constant pressure dropping funnel to slowly and dropwise add solution B to the mixture, control the dropping speed to 1 drop per second to form a mixture;

[0030] (2) Add 25% ammonia water by mass slowly to the mixture while monitoring the pH until the pH value of the system stabilizes at 9 and an orange-red transparent sol is formed. Transfer all of the above sol to a high-pressure reactor with a polytetrafluoroethylene liner, seal the reactor, and place it in a forced-air drying oven. Perform the hydrothermal reaction according to the following procedure: raise the temperature from room temperature to 120°C at a rate of 2°C / min and keep it at 120°C for 8 hours. Then raise the temperature to 180°C at a rate of 1°C / min and keep it at 180°C for 20 hours. After the reaction is completed, cool it naturally to room temperature and then centrifuge it at 8000 rpm for 10 minutes. Discard the supernatant and use a 1:1 volume ratio ethanol-deionized water mixture as a washing agent to perform ultrasonic redispersion and centrifugal washing of the precipitate. Repeat this process 3 times. Dry it under vacuum conditions of 80°C and -0.09 MPa for 6 hours to obtain the precursor powder.

[0031] (3) Place the dried precursor powder in an alumina crucible, then place it in a quartz boat in the constant temperature zone of a tube furnace, connect the gas path, and ensure good sealing. Then, perform heat treatment according to the following procedure: introduce dry air at a flow rate of 50 mL / min to purge the furnace chamber for 30 minutes. Increase the furnace temperature from room temperature to 350°C at a heating rate of 2°C / min and hold it at this temperature for 2 hours. Switch the inlet gas to high-purity nitrogen at a flow rate of 50 mL / min and then increase the temperature to 450°C at a rate of 5°C / min. Hold it at this temperature for 2 hours. After the heat treatment is completed, turn off the heating power supply and allow the furnace to cool naturally to below 50°C under continuous nitrogen supply. Grind the catalyst gently with an agate mortar and pass it through a 400-mesh standard sieve to obtain the catalyst.

[0032] This embodiment also provides a method for preparing an absorbent for treating organic waste gas, specifically including the following steps:

[0033] S1, weigh graphene oxide and add it to a freshly prepared mixed acid solution made of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 (1 mg: 1 mL). Place the solution in an ice-water bath and connect a reflux condenser. With stirring, treat the solution at a depth of 1 cm below the liquid surface using a 400 W ultrasonic probe for 3 hours, maintaining the ice bath temperature at 15°C during treatment. After treatment, slowly pour the solution into deionized water for dilution and filter under reduced pressure using a 0.22 µm polyethersulfone membrane. Wash the solution with deionized water until the pH of the filtrate is neutral. Redisperse the resulting product on anhydrous DM... In step F, a graphene dispersion with a concentration of 1.5 mg / mL was formed. KH-550 and 4-dimethylaminopyridine were added to the graphene dispersion. Under nitrogen protection, the mixture was heated to 80°C and stirred under reflux for 24 hours. After the reaction was completed, DCC was added, wherein the volume ratio of graphene dispersion to KH-550 was 50:1. The reaction was continued at 80°C for 12 hours. The reaction solution was transferred to a centrifuge tube and washed 5 times alternately with anhydrous DMF and anhydrous ethanol. Finally, the product was redispersed in anhydrous ethanol to obtain a stable aminated graphene dispersion.

[0034] S2, weigh the catalyst, add anhydrous ethanol, the ratio of catalyst to anhydrous ethanol is 1g:25mL, sonicate for 30 minutes to fully disperse it to obtain a suspension, mix the suspension with the amino graphene dispersion, and then add glacial acetic acid to form a mixed system, the volume ratio of glacial acetic acid to amino graphene dispersion is 1:1000, and stir the mixed system in a 60℃ water bath at 300rpm for 8 hours. After the reaction is completed, collect the solid product by centrifugation, wash it 3 times with ethanol, and finally dry it to constant weight in a 60℃ vacuum drying oven to obtain composite powder;

[0035] S3, N-isopropylacrylamide, MBA and initiator BPO were added to the functionalized ionic liquid, wherein the mass ratio of N-isopropylacrylamide, MBA and initiator BPO was 5:0.5:0.1, tetrahydrofuran was added to dissolve it, and the ratio of N-isopropylacrylamide to tetrahydrofuran was 0.25g:20mL, and the mixture was refluxed at 70℃ for 6 hours. After the polymerization was completed, the solvent was removed by rotary evaporation to obtain the thermosensitive ionic liquid prepolymer.

[0036] S4. Dissolve the thermosensitive ionic liquid prepolymer in cyclohexane and sonicate until completely dissolved to form an oil phase. The ratio of thermosensitive ionic liquid prepolymer to cyclohexane is 0.5 g: 20 mL. Weigh the composite powder and add a solution containing 0.5% (by mass) of... In SDS-treated deionized water, the ratio of composite powder to deionized water was 0.1 g: 50 mL. The mixture was vigorously stirred and sonicated for 30 minutes to form an aqueous phase. In a high-speed shear disperser, the oil phase was slowly poured into the aqueous phase and emulsified at 10,000 rpm for 5 minutes to form a stable oil-in-water emulsion. Potassium persulfate was added to the emulsion at a ratio of 15 mL: 1 mg. The mixture was then transferred to a 70°C water bath and stirred at 300 rpm for 6 hours to complete interfacial polymerization. After the reaction, the product was filtered through a Buchner funnel and washed three times with a large amount of ethanol and deionized water. The filter cake was then dried in a 40°C vacuum drying oven for 12 hours to obtain an absorbent for treating organic waste gas.

[0037] The preparation method of the functionalized ionic liquid includes the following steps:

[0038] Weigh 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and dichloromethane. Under ice-water bath and stirring, slowly add acryloyl chloride dropwise using a constant pressure dropping funnel. The ratio of 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, dichloromethane and acryloyl chloride is 1 g: 40 mL: 0.5 mL. Control the dropping time to 30 minutes. After the addition is complete, remove the ice bath and let the reaction continue to be stirred at room temperature for 12 hours. After the reaction is complete, remove dichloromethane using a rotary evaporator to obtain the functionalized ionic liquid.

[0039] Example 2: This example provides an absorbent for treating organic waste gas, which comprises the following raw materials in parts by weight: 15 parts graphene oxide, 25 parts catalyst, 30 parts functionalized ionic liquid, 15 parts N-isopropylacrylamide, 8 parts 4-dimethylaminopyridine, and 20 parts DCC.

[0040] The catalyst comprises raw materials in the following mass ratio: Ce(NO3)3·6H2O:Co(NO3)2·6H2O:sodium selenate:urea:PVP=1.2:0.9:0.6:1.2:0.1;

[0041] The method for preparing the catalyst includes the following steps:

[0042] (1) Weigh Ce(NO3)3·6H2O and cobalt nitrate hexahydrate, add ethylene glycol, the ratio of Ce(NO3)3·6H2O to ethylene glycol is 1g:40mL, place in a 60℃ constant temperature water bath, dissolve under magnetic stirring to form solution A, weigh sodium selenate and dissolve in deionized water, the ratio of sodium selenate to deionized water is 0.3g:15mL, after complete dissolution to form solution B, add PVP and urea to solution A in sequence to obtain a mixture, sonicate the mixture for 10 minutes to ensure that the additives are fully dispersed, under continuous magnetic stirring, use a constant pressure dropping funnel to slowly and dropwise add solution B to the mixture, control the dropping speed to 1 drop per second to form a mixture;

[0043] (2) Add 25% ammonia water by mass slowly to the mixture, while monitoring with a precision pH meter until the pH value of the system stabilizes at 9.5 and an orange-red transparent sol is formed. Transfer all of the above sol to a high-pressure reactor with a polytetrafluoroethylene liner, seal the reactor, and place it in a forced-air drying oven. Perform the hydrothermal reaction according to the following procedure: raise the temperature from room temperature to 120°C at a rate of 2°C / min and keep it at 120°C for 8 hours. Then raise the temperature to 180°C at a rate of 1°C / min and keep it at 180°C for 20 hours. After the reaction is completed, cool it naturally to room temperature and then centrifuge it at 8000 rpm for 10 min. Discard the supernatant and use a 1:1 volume ratio ethanol-deionized water mixture as a washing agent to perform ultrasonic redispersion and centrifugal washing of the precipitate. Repeat this process 3 times. Dry it under vacuum conditions of 80°C and -0.09 MPa for 6 hours to obtain the precursor powder.

[0044] (3) Place the dried precursor powder in an alumina crucible, then place it in a quartz boat in the constant temperature zone of a tube furnace, connect the gas path, and ensure good sealing. Then, perform heat treatment according to the following procedure: introduce dry air at a flow rate of 50 mL / min to purge the furnace chamber for 30 minutes. Increase the furnace temperature from room temperature to 350°C at a heating rate of 2°C / min and hold it at this temperature for 2 hours. Switch the inlet gas to high-purity nitrogen at a flow rate of 50 mL / min and then increase the temperature to 450°C at a rate of 5°C / min. Hold it at this temperature for 2 hours. After the heat treatment is completed, turn off the heating power supply and allow the furnace to cool naturally to below 50°C under continuous nitrogen supply. Grind the catalyst gently with an agate mortar and pass it through a 400-mesh standard sieve to obtain the catalyst.

[0045] This embodiment also provides a method for preparing an absorbent for treating organic waste gas, specifically including the following steps:

[0046] S1. Weigh graphene oxide and add it to a freshly prepared mixed acid solution made of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 (1 mg: 1 mL). Place the solution in an ice-water bath and connect a reflux condenser. With stirring, treat the solution at a depth of 1 cm below the liquid surface using a 400 W ultrasonic probe for 3 hours, maintaining the ice bath temperature at 10°C during treatment. After treatment, slowly pour the solution into deionized water for dilution and perform vacuum filtration using a 0.22 µm polyethersulfone membrane. Wash the solution with deionized water until the pH of the filtrate is neutral. Redisperse the resulting product in anhydrous DMF. A graphene dispersion with a concentration of 2 mg / mL was formed. KH-550 and 4-dimethylaminopyridine were added to the graphene dispersion. Under nitrogen protection, the mixture was heated to 80°C and stirred under reflux for 24 hours. After the reaction was completed, DCC was added, with the volume ratio of graphene dispersion to KH-550 being 50:1. The reaction was continued at 80°C for 12 hours. The reaction solution was transferred to a centrifuge tube and washed 5 times alternately with anhydrous DMF and anhydrous ethanol. Finally, the product was redispersed in 100 mL of anhydrous ethanol to obtain a stable aminated graphene dispersion.

[0047] S2, weigh the catalyst, add anhydrous ethanol, the ratio of catalyst to anhydrous ethanol is 1g:25mL, sonicate for 30 minutes to fully disperse it to obtain a suspension, mix the suspension with the amino graphene dispersion, and then add glacial acetic acid to form a mixed system, the volume ratio of glacial acetic acid to amino graphene dispersion is 1:1000, and stir the mixed system in a 60℃ water bath at 300rpm for 8 hours. After the reaction is completed, collect the solid product by centrifugation, wash it 3 times with ethanol, and finally dry it to constant weight in a 60℃ vacuum drying oven to obtain composite powder;

[0048] S3, N-isopropylacrylamide, MBA and initiator BPO were added to the functionalized ionic liquid, wherein the mass ratio of N-isopropylacrylamide, MBA and initiator BPO was 5:0.5:0.1, tetrahydrofuran was added to dissolve it, and the ratio of N-isopropylacrylamide to tetrahydrofuran was 0.25g:20mL, and the mixture was refluxed at 70℃ for 6 hours. After the polymerization was completed, the solvent was removed by rotary evaporation to obtain the thermosensitive ionic liquid prepolymer.

[0049] S4. Dissolve the thermosensitive ionic liquid prepolymer in cyclohexane and sonicate until completely dissolved to form an oil phase. The ratio of thermosensitive ionic liquid prepolymer to cyclohexane is 0.5 g: 20 mL. Weigh the composite powder and add a solution containing 0.5% (by mass) of... In SDS-treated deionized water, the ratio of composite powder to deionized water was 0.1 g: 50 mL. The mixture was vigorously stirred and sonicated for 30 minutes to form an aqueous phase. In a high-speed shear disperser, the oil phase was slowly poured into the aqueous phase and emulsified at 10,000 rpm for 5 minutes to form a stable oil-in-water emulsion. Potassium persulfate was added to the emulsion at a ratio of 20 mL: 1 mg. The mixture was then transferred to a 70°C water bath and stirred at 300 rpm for 6 hours to complete interfacial polymerization. After the reaction, the product was filtered through a Buchner funnel and washed three times with a large amount of ethanol and deionized water. The filter cake was then dried in a 40°C vacuum drying oven for 12 hours to obtain an absorbent for treating organic waste gas.

[0050] The preparation method of the functionalized ionic liquid includes the following steps:

[0051] Weigh 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and dichloromethane. Under ice-water bath and stirring, slowly add acryloyl chloride dropwise using a constant pressure dropping funnel. The ratio of 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, dichloromethane and acryloyl chloride is 1 g: 50 mL: 0.5 mL. Control the dropping time to 40 minutes. After the dropping is complete, remove the ice bath and let the reaction continue to be stirred at room temperature for 12 hours. After the reaction is complete, remove dichloromethane using a rotary evaporator to obtain the functionalized ionic liquid.

[0052] Example 3: This example provides an absorbent for treating organic waste gas, which comprises the following raw materials in parts by weight: 25 parts graphene oxide, 30 parts catalyst, 40 parts functionalized ionic liquid, 20 parts N-isopropylacrylamide, 10 parts 4-dimethylaminopyridine, and 25 parts DCC.

[0053] The catalyst comprises raw materials in the following mass ratio: Ce(NO3)3·6H2O:Co(NO3)2·6H2O:sodium selenate:urea:PVP (polyvinylpyrrolidone) = 1.5:0.9:0.6:1.2:0.1;

[0054] The method for preparing the catalyst includes the following steps:

[0055] (1) Weigh Ce(NO3)3·6H2O and cobalt nitrate hexahydrate, add ethylene glycol, the ratio of Ce(NO3)3·6H2O to ethylene glycol is 1g:40mL, place in a 60℃ constant temperature water bath, dissolve under magnetic stirring to form solution A, weigh sodium selenate and dissolve in deionized water, the ratio of sodium selenate to deionized water is 0.3g:15mL, after complete dissolution to form solution B, add PVP and urea to solution A in sequence to obtain a mixture, sonicate the mixture for 10 minutes to ensure that the additives are fully dispersed, under continuous magnetic stirring, use a constant pressure dropping funnel to slowly and dropwise add solution B to the mixture, control the dropping speed to 1 drop per second to form a mixture;

[0056] (2) Add 25% ammonia water by mass slowly to the mixture, while monitoring with a precision pH meter until the pH value of the system stabilizes at 10 and an orange-red transparent sol is formed. Transfer all of the above sol to a high-pressure reactor with a polytetrafluoroethylene liner, seal the reactor, and place it in a forced-air drying oven. Perform the hydrothermal reaction according to the following procedure: raise the temperature from room temperature to 120°C at a rate of 2°C / min and keep it at 120°C for 8 hours. Then raise the temperature to 180°C at a rate of 1°C / min and keep it at 180°C for 20 hours. After the reaction is completed, cool it naturally to room temperature and then centrifuge it at 8000 rpm for 10 min. Discard the supernatant and use a 1:1 volume ratio ethanol-deionized water mixture as a washing agent to perform ultrasonic redispersion and centrifugal washing of the precipitate. Repeat this process 3 times. Dry it under vacuum conditions of 80°C and -0.09 MPa for 6 hours to obtain the precursor powder.

[0057] (3) Place the dried precursor powder in an alumina crucible, then place it in a quartz boat in the constant temperature zone of a tube furnace, connect the gas path, and ensure good sealing. Then, perform heat treatment according to the following procedure: introduce dry air at a flow rate of 50 mL / min to purge the furnace chamber for 30 minutes. Increase the furnace temperature from room temperature to 350°C at a heating rate of 2°C / min and hold it at this temperature for 2 hours. Switch the inlet gas to high-purity nitrogen at a flow rate of 50 mL / min and then increase the temperature to 450°C at a rate of 5°C / min. Hold it at this temperature for 2 hours. After the heat treatment is completed, turn off the heating power supply and allow the furnace to cool naturally to below 50°C under continuous nitrogen supply. Grind the catalyst gently with an agate mortar and pass it through a 400-mesh standard sieve to obtain the catalyst.

[0058] This embodiment also provides a method for preparing an absorbent for treating organic waste gas, specifically including the following steps:

[0059] S1, weigh graphene oxide and add it to a freshly prepared mixed acid solution made of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 (1 mg: 1 mL). Place the solution in an ice-water bath and connect a reflux condenser. With stirring, treat the solution at a depth of 1 cm below the liquid surface using a 400 W ultrasonic probe for 3 hours, maintaining the ice bath temperature at 20°C during treatment. After treatment, slowly pour the solution into deionized water for dilution and perform vacuum filtration using a 0.22 µm polyethersulfone membrane. Wash the solution with deionized water until the pH of the filtrate is neutral. Redisperse the resulting product in anhydrous DMF. A graphene dispersion with a concentration of 3 mg / mL was formed. KH-550 and 4-dimethylaminopyridine were added to the graphene dispersion. Under nitrogen protection, the mixture was heated to 80°C and stirred under reflux for 24 hours. After the reaction was completed, DCC was added, with the volume ratio of graphene dispersion to KH-550 being 50:1. The reaction was continued at 80°C for 12 hours. The reaction solution was transferred to a centrifuge tube and washed 5 times alternately with anhydrous DMF and anhydrous ethanol. Finally, the product was redispersed in 100 mL of anhydrous ethanol to obtain a stable aminated graphene dispersion.

[0060] S2, weigh the catalyst, add anhydrous ethanol, the ratio of catalyst to anhydrous ethanol is 1g:25mL, sonicate for 30 minutes to fully disperse it to obtain a suspension, mix the suspension with the amino graphene dispersion, and then add glacial acetic acid to obtain a mixed system, the volume ratio of glacial acetic acid to amino graphene dispersion is 1:1000, and stir the mixed system in a 60℃ water bath at 300rpm for 8 hours. After the reaction is completed, collect the solid product by centrifugation, wash it 3 times with ethanol, and finally dry it to constant weight in a 60℃ vacuum drying oven to obtain composite powder;

[0061] S3, N-isopropylacrylamide, MBA and initiator BPO were added to the functionalized ionic liquid, wherein the mass ratio of N-isopropylacrylamide, MBA and initiator BPO was 5:0.5:0.1, tetrahydrofuran was added to dissolve it, and the ratio of N-isopropylacrylamide to tetrahydrofuran was 0.25g:20mL, and the mixture was refluxed at 70℃ for 6 hours. After the polymerization was completed, the solvent was removed by rotary evaporation to obtain the thermosensitive ionic liquid prepolymer.

[0062] S4. Dissolve the thermosensitive ionic liquid prepolymer in cyclohexane and sonicate until completely dissolved to form an oil phase. The ratio of thermosensitive ionic liquid prepolymer to cyclohexane is 0.5 g: 20 mL. Weigh the composite powder and add a solution containing 0.5% (by mass) of... In SDS-treated deionized water, the ratio of composite powder to deionized water was 0.1 g: 50 mL. The mixture was vigorously stirred and sonicated for 30 minutes to form an aqueous phase. In a high-speed shear disperser, the oil phase was slowly poured into the aqueous phase and emulsified at 10,000 rpm for 5 minutes to form a stable oil-in-water emulsion. Potassium persulfate was added to the emulsion at a ratio of 20 mL: 1 mg. The mixture was then transferred to a 70°C water bath and stirred at 300 rpm for 6 hours to complete interfacial polymerization. After the reaction, the product was filtered through a Buchner funnel and washed three times with a large amount of ethanol and deionized water. The filter cake was then dried in a 40°C vacuum drying oven for 12 hours to obtain an absorbent for treating organic waste gas.

[0063] The preparation method of the functionalized ionic liquid includes the following steps:

[0064] Weigh 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and dichloromethane. Under ice-water bath and stirring, slowly add acryloyl chloride dropwise using a constant pressure dropping funnel. The ratio of 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, dichloromethane and acryloyl chloride is 1 g: 60 mL: 0.5 mL. Control the dropping time to 50 minutes. After the dropping is complete, remove the ice bath and let the reaction continue to be stirred at room temperature for 12 hours. After the reaction is complete, remove dichloromethane using a rotary evaporator to obtain the functionalized ionic liquid.

[0065] The difference between Comparative Example 1 and Example 2 is that no catalyst is added; the rest is exactly the same as Example 2.

[0066] The difference between Comparative Example 2 and Example 2 is that no functionalized ionic liquid is added; the rest is exactly the same as Example 2.

[0067] Experimental example:

[0068] Adsorption capacity test: The adsorption performance of the absorbents prepared for organic waste gas treatment in Examples 1-3 and Comparative Examples 1-2 of this invention was tested using the dynamic adsorption breakthrough method. The testing apparatus mainly consisted of a mass flow meter, a VOCs vapor generator, a constant-temperature fixed-bed reactor (10 mm inner diameter), and an online gas chromatograph. All gas pipelines were made of polytetrafluoroethylene and placed in a constant-temperature chamber at 25°C to eliminate the influence of temperature fluctuations. 100 mg of the composite absorbent prepared in this invention was accurately weighed. All samples were degassed at 105°C under a nitrogen atmosphere for 2 hours before use to remove surface-adsorbed moisture and impurities, and then cooled to room temperature. The pretreated samples were uniformly packed into the constant-temperature zone of the reaction tube, and both ends were fixed with quartz wool to ensure a tight bed without channeling. Toluene is used as an example below; the testing steps for other VOCs (ethyl acetate, methanethiol, formaldehyde) are the same, only the liquid in the vapor generator bottle needs to be replaced. The carrier gas was turned on, and the system was purged at the flow rate corresponding to the test space velocity for at least 30 minutes until the online gas chromatogram baseline stabilized. Switch the valve to allow the prepared toluene-containing standard gas to pass through the sample bed at a constant space velocity. Simultaneously, start data recording and record the toluene concentration at the reactor outlet every 2 minutes. Breakthrough determination: Continuously introduce VOCs until the ratio of outlet concentration to inlet concentration (C / C0) reaches and stabilizes above 0.95, which is considered as complete adsorption saturation, and stop the test. The adsorption capacity results are recorded in Table 1.

[0069] Anti-poisoning performance: Using the absorbents for organic waste gas treatment prepared in Examples 1-3 and Comparative Examples 1-2 of this invention as samples, the samples were dried in a vacuum drying oven at 60°C for 2 hours for later use; simulated waste gas preparation: using nitrogen as the balance gas, mixed waste gases containing methanethiol and toluene (toluene concentration 50 mg / m³) were prepared separately. 3 Methanethiol concentration 5 mg / m 3 Simulated industrial waste gas containing sulfur impurities), pure toluene waste gas (50 mg / m³) 3 (Blank control group). 0.5 g of dried absorbent was packed into a fixed-bed reactor, and pure toluene waste gas was introduced. The reaction temperature was controlled at 100℃ and the space velocity at 10000 h⁻¹. -1 After 1 hour of stable operation, the concentrations of toluene at the inlet and outlet of the reactor were detected by gas chromatography, and the initial degradation efficiency was calculated. Switch to a mixed waste gas containing methanethiol and toluene, maintain the same reaction conditions, and run continuously for 24 hours. Monitor the inlet and outlet toluene concentrations every 4 hours and calculate the degradation efficiency at different time points. ). Calculate the degradation efficiency retention rate after 24 h (). The degradation efficiency retention rate after 24 hours (×100%) is recorded in Table 1.

[0070] Table 1: Performance test results of the absorbent prepared in this invention for treating organic waste gas

[0071]

[0072] Table 1 shows that the adsorption capacity of the examples was significantly higher than that of Comparative Examples 1 and 2, indicating that the synergistic addition of the catalyst and ionic liquid not only provided additional adsorption sites but also optimized the adsorption structure through interfacial interactions, thereby enhancing the adsorption capacity for various organic waste gases. Specifically, the increased adsorption capacity for toluene and ethyl acetate was mainly due to the hydrophobic selective adsorption of the ionic liquid, the increased adsorption capacity for formaldehyde was mainly due to the synergistic chemisorption of the catalyst and amino-functionalized GO, and the increased adsorption capacity for methanethiol was due to the anti-poisoning site effect of the heterojunction. The degradation efficiency remained above 90% after 24 hours, indicating that the absorbent prepared in this invention for treating organic waste gases can maintain a high degradation retention rate in sulfur-containing toxic waste gases and possesses excellent anti-poisoning performance.

[0073] Figure 1 The results show that the catalyst prepared by this invention exhibits a flower-like structure, has a large specific surface area, and does not show any aggregation. Figure 2 The results of the cycle stability of the absorbent for treating organic waste gas prepared using Example 2 of the present invention are shown. Figure 2 It is evident that the absorbent maintains a beneficial catalytic degradation efficiency even after multiple cycles. This demonstrates good stability, indicating that the absorbent prepared in this invention for treating organic waste gas can further degrade the adsorbed organic waste gas, regenerating the absorbent and exhibiting excellent cycle stability.

[0074] In summary, this invention successfully prepared a high-performance organic waste gas treatment absorbent. During the preparation process, the synergistic application of hydrothermal reaction and programmed temperature-controlled pyrolysis achieved atomic-level interfacial fusion of cerium selenate and cobalt oxide, forming a highly efficient catalytic heterojunction. The carboxylation enhancement of graphene oxide and the grafting modification with aminosilane not only strengthened the chemical adsorption capacity for organic waste gas molecules but also provided stable anchoring points for the heterojunction particles, effectively inhibiting particle aggregation. The temperature-sensitive ionic liquid microcapsules formed by interfacial polymerization endowed the material with hydrophobic protection and temperature-responsive properties, while protecting the internal active components. The preparation process is highly controllable and reproducible, and the product is adaptable to various industrial organic waste gas treatment scenarios, possessing significant technological innovation and practical application value. It provides a feasible technical solution for the efficient, long-term, and low-cost treatment of organic waste gas.

[0075] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An absorbent for treating organic waste gas, characterized in that, The raw materials include the following parts by weight: 10-25 parts graphene oxide, 20-30 parts catalyst, 25-40 parts functionalized ionic liquid, 10-20 parts N-isopropylacrylamide, 5-10 parts 4-dimethylaminopyridine, and 15-25 parts DCC. The preparation process of the functionalized ionic liquid is as follows: weigh 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, add dichloromethane, add acryloyl chloride under ice-water bath and stirring, and rotary evaporate to obtain the functionalized ionic liquid; The catalyst comprises raw materials in the following mass ratio: Ce(NO3)3·6H2O:Co(NO3)2·6H2O:sodium selenate:urea:PVP=1-1.5:0.9:0.6:1.2:0.1; The method for preparing the catalyst includes the following steps: (1) Weigh Ce(NO3)3·6H2O and Co(NO3)2·6H2O, add ethylene glycol, stir at constant temperature to form solution A, weigh sodium selenate and dissolve it in deionized water to form solution B, add PVP and urea to solution A in sequence to obtain a mixture, sonicate the mixture, and then add solution B to the mixture to form a mixture; (2) Add ammonia water dropwise to the mixture to adjust the pH and form a sol. Perform a hydrothermal reaction on the sol, cool, centrifuge, wash, and vacuum dry to obtain the precursor powder. (3) The precursor powder is heat-treated, then cooled naturally, ground and sieved to obtain the catalyst; The preparation method of the absorbent for treating organic waste gas specifically includes the following steps: S1. Weigh graphene oxide, add it to a mixed acid solution, sonicate, then dilute, filter under reduced pressure, wash, and obtain a filter cake. Redisperse the filter cake in DMF to form a graphene dispersion. Add KH-550 and 4-dimethylaminopyridine to the graphene dispersion, heat under reflux in an inert atmosphere to carry out an amination reaction, then add DCC, heat to react, centrifuge and wash, and redisperse the product in anhydrous ethanol to obtain an aminated graphene dispersion. S2, weigh the catalyst, add anhydrous ethanol, ultrasonically disperse to obtain a suspension, mix the suspension with the amino graphene dispersion, stir, centrifuge to collect the solid product, wash, vacuum dry to obtain composite powder; S3, add N-isopropylacrylamide, MBA and initiator BPO to the functionalized ionic liquid, then add tetrahydrofuran to dissolve, reflux and polymerize to obtain a thermosensitive ionic liquid prepolymer; S4. The temperature-sensitive ionic liquid prepolymer is dissolved in cyclohexane and sonicated to form an oil phase. The composite powder is weighed and added to deionized water and stirred to form an aqueous phase. Then, the oil phase is poured into the aqueous phase and emulsified by high-speed shearing to form an emulsion. Potassium persulfate is added to the emulsion, stirred, filtered, washed, and dried to obtain an absorbent for the treatment of organic waste gas.

2. The absorbent for treating organic waste gas according to claim 1, characterized in that, In step (1), the ratio of Ce(NO3)3·6H2O to ethylene glycol is 1g:40mL; the ratio of sodium selenate to deionized water is 0.3g:10-15mL. In step (2), the temperature control of the hydrothermal reaction is as follows: the temperature is increased from room temperature to 120°C at a rate of 2°C / min and kept constant at 120°C for 8 hours, then the temperature is increased to 180°C at a rate of 1°C / min and kept constant at 180°C for 20 hours.

3. The absorbent for treating organic waste gas according to claim 1, characterized in that, In step (3), the heat treatment is as follows: the temperature is increased from room temperature to 350°C at a rate of 2°C / min and held at that temperature for 2 hours, then the temperature is increased to 450°C at a rate of 5°C / min and held at that temperature for 2 hours.

4. A method for preparing an absorbent for treating organic waste gas according to any one of claims 1-3, characterized in that, Specifically, the following steps are included: S1. Weigh graphene oxide, add it to a mixed acid solution, sonicate, then dilute, filter under reduced pressure, wash, and obtain a filter cake. Redisperse the filter cake in DMF to form a graphene dispersion. Add KH-550 and 4-dimethylaminopyridine to the graphene dispersion, heat under reflux in an inert atmosphere to carry out an amination reaction, then add DCC, heat to react, centrifuge and wash, and redisperse the product in anhydrous ethanol to obtain an aminated graphene dispersion. S2, weigh the catalyst, add anhydrous ethanol, ultrasonically disperse to obtain a suspension, mix the suspension with the amino graphene dispersion, stir, centrifuge to collect the solid product, wash, vacuum dry to obtain composite powder; S3, add N-isopropylacrylamide, MBA and initiator BPO to the functionalized ionic liquid, then add tetrahydrofuran to dissolve, reflux and polymerize to obtain a thermosensitive ionic liquid prepolymer; S4. The temperature-sensitive ionic liquid prepolymer is dissolved in cyclohexane and sonicated to form an oil phase. The composite powder is weighed and added to deionized water and stirred to form an aqueous phase. Then, the oil phase is poured into the aqueous phase and emulsified by high-speed shearing to form an emulsion. Potassium persulfate is added to the emulsion, stirred, filtered, washed, and dried to obtain an absorbent for the treatment of organic waste gas.

5. The method for preparing an absorbent for treating organic waste gas according to claim 4, characterized in that, In step S1, the mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1; the volume ratio of graphene oxide to the mixed acid solution is 1 mg: 1 mL; the volume ratio of graphene dispersion to KH-550 is 50:1; and the volume ratio of the product to anhydrous ethanol is 1 mg: 5-10 mL.

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