Porous medium catalyst for efficiently degrading VOCs (Volatile Organic Compounds) as well as preparation and application thereof

Abstract

The invention discloses a porous medium catalyst for efficiently degrading VOCs (volatile organic compounds) as well as preparation and application thereof. The preparation method of the catalyst comprises the following steps: placing a porous medium material in a dilute alkali solution, carrying out hydrothermal treatment to remove surface impurities and etch a microporous structure, taking out the porous medium material, alternately washing the porous medium material with ethanol and deionized water until the porous medium material is neutral, and drying the porous medium material; soaking the porous medium carrier in a modification liquid containing organic acid, organic amine and a chelating agent, soaking in a water bath, taking out and drying, and repeating the water bath soaking step for 2-5 times to obtain a doped and modified porous medium carrier; soaking in a precursor solution, and promoting metal ions to quickly diffuse into the pore channels by adopting intermittent microwave heating; afterwards, redundant solution is purged through inert gas, and low-temperature drying is conducted; and then placing in an atmosphere furnace, and calcining in an environment of introducing 5% O2 / N2 mixed gas to obtain the porous medium catalyst. The porous medium catalyst prepared by the method is more uniform in loading of surface active components, and shows excellent low-temperature catalytic oxidation performance of VOCs (Volatile Organic Compounds).

Description

Technical Field

[0001] This invention belongs to the field of air pollution control technology, specifically relating to a highly efficient porous media catalyst for degrading VOCs, its preparation, and its application. Background Technology

[0002] VOCs are highly reactive and toxic, causing various environmental and health problems, and are important precursors to PM2.5 and ozone. NO... x This is one of the main causes of acid rain and photochemical smog, both of which often coexist in high-temperature flue gas from industries such as chemical, petrochemical, printing and dyeing, rubber, synthetic materials, metallurgy, and building materials. Volatile organic compounds (VOCs) and nitrogen oxides (NOx) are also present in industrial flue gas. x The coordinated governance of ( ) is a key issue in industrial waste gas treatment.

[0003] Existing treatment technologies, such as regenerative thermal oxidation (RTO), plasma oxidation, and photocatalytic oxidation, suffer from problems in engineering practice, including high energy consumption, frequent maintenance, and difficulty in controlling byproducts. Furthermore, they often struggle to address diverse emission scenarios, including high and low concentrations, single and multi-component emissions, and dry and high-humidity conditions. Meanwhile, the currently mainstream powdered catalysts or granular bed structures are ill-suited to the high flow rates, large volumes, and frequent temperature fluctuations of industrial flue gas, exhibiting significant limitations in thermal stability, mechanical strength, and reaction efficiency.

[0004] Porous media catalytic materials, as functional materials that combine thermal conductivity, structural stability, and reactivity, have gradually gained attention in the field of industrial flue gas treatment in recent years. These materials typically use foam ceramics, honeycomb ceramics, or metal foams as supporting carriers, and composite-load transition metals (such as Mn, Cu, Fe, Co) or rare earth elements (such as Ce, La) as catalytic components. They can achieve highly efficient catalytic oxidation of VOCs in a medium-low temperature range of 200–450 °C, with typical removal rates exceeding 90%, while avoiding secondary pollution.

[0005] However, current porous media catalysts still face the following challenges: (1) poor dispersion of catalytic components, active metals are prone to agglomeration or loss, resulting in limited service life; (2) some support materials are prone to cracking or strength reduction under high temperature or temperature fluctuation, affecting catalytic stability; (3) complex preparation process, poor environmental friendliness, and difficulty in achieving low-cost large-scale production.

[0006] Therefore, it is essential to provide a porous media catalyst with high dispersion of active metal components and high catalytic activity for environmental remediation. Summary of the Invention

[0007] To address at least one of the aforementioned problems, this invention provides a porous media catalyst for the efficient degradation of VOCs, its preparation, and its application. The porous media catalyst prepared by this method exhibits a more uniform surface loading of active components and demonstrates excellent VOCs catalytic oxidation performance.

[0008] To achieve the above objectives, the present invention employs the following technical means: The first aspect of this invention provides a method for preparing a porous media catalyst for the efficient degradation of VOCs, comprising the following steps: S1. Place the porous media material in a dilute alkaline solution, perform hydrothermal treatment to remove surface impurities and etch out the microporous structure, remove it and wash it alternately with ethanol and deionized water until neutral, and then dry it. S2. Immerse the porous media material obtained in S1 in a modification solution containing organic acid, organic amine and chelating agent, soak it in water bath, take it out and dry it, and repeat the water bath soaking step 2 to 5 times to obtain the doped and modified porous media carrier. S3. The porous medium support modified by doping in S2 is immersed in the precursor solution, and intermittent microwave heating is used to promote the rapid diffusion of metal ions into the pores; then, excess solution is purged with inert gas and dried at low temperature. S4. The dried porous media support from S3 is placed in an atmosphere furnace and calcined under an environment of 5% O2 / N2 mixed gas to obtain a porous media catalyst.

[0009] In some embodiments of the present invention, in step S1, the dilute alkaline solution is NaOH and / or KOH, with a concentration of 0.1~0.3 mol / L.

[0010] In some embodiments of the present invention, in step S1, the hydrothermal treatment temperature is 60~80 ℃ and the treatment time is 2~4 hours.

[0011] In some embodiments of the present invention, in step S2, the organic acid includes one or more of oxalic acid, citric acid, tartaric acid, malic acid, and glycine.

[0012] In some embodiments of the present invention, in step S2, the organic amine and chelating agent include one or more of ethanolamine, triethanolamine, and ethylenediaminetetraacetic acid.

[0013] In some embodiments of the present invention, in step S2, the concentrations of organic acid, organic amine and chelating agent in the modification solution are 0.01-0.5 mol / L.

[0014] In some embodiments of the present invention, in step S3, the active metal source includes one of manganese acetate and cobalt acetate, or a combination of manganese acetate, cobalt acetate and one of zirconium acetate and nickel acetate.

[0015] In some embodiments of the present invention, in step S3, the concentration of the precursor solution is 0.1-0.5 mol / L.

[0016] In some embodiments of the present invention, in step S3, the intermittent microwave heating treatment is performed with a power of 300W, on for 10 seconds and off for 20 seconds, for a total of 5 to 20 minutes.

[0017] In some embodiments of the present invention, in step S4, the calcination temperature of the porous media catalyst is 450~650℃, and the calcination time is 2-4 hours.

[0018] A second aspect of the present invention provides a porous media catalyst prepared using the method described in the first aspect.

[0019] A third aspect of the invention provides the application of the porous media catalyst described in the second aspect, or the porous media catalyst prepared by the method described in the first aspect, in the efficient removal of VOCs from industrial flue gas. In some embodiments of the invention, the application temperature is below 210 °C.

[0020] Beneficial effects of the present invention Compared with existing technologies, this invention has the following advantages: This invention provides a porous media catalyst for the efficient removal of VOCs from industrial flue gas. It is prepared using a multifunctional organic modification liquid impregnation method, utilizing the coordination interaction between organic functional groups (such as -COOH, -NH, etc.) and metal ions to achieve uniform dispersion of active sites on the surface of the porous media support. Combined with an intermittent microwave loading method, it helps to limit the aggregation and growth of metal nanoparticles or the active phase, thereby obtaining active species with smaller particle size and narrower distribution, improving the specific surface area and dispersion of the catalyst. The prepared porous media catalytic material exhibits excellent VOCs catalytic oxidation performance and has good application prospects in the removal of VOCs from industrial flue gas. Attached Figure Description

[0021] Figure 1 This is a SEM image of the porous media material in Example 1 after organic acid pretreatment; Figure 2 The image shows the SEM analysis of the porous Mn-based catalytic material in Example 1. Figure 3 The image shows the SEM analysis of the porous Mn-based catalytic material in Comparative Example 1. Figure 4 The image shows the SEM analysis of the porous Mn-based catalytic material in Comparative Example 2. Figure 5 The image shows the SEM analysis of the porous Mn-based catalytic material in Comparative Example 3. Figure 6 The image shows the SEM analysis of the porous Mn-based catalytic material in Comparative Example 4. Figure 7 This is a comparison chart showing the activity of the catalytic materials in Example 1 and Comparative Examples 1-4 in terms of toluene removal efficiency. Detailed Implementation

[0022] The following examples are used to illustrate preferred embodiments of the invention. Those skilled in the art will understand that the techniques disclosed in the examples represent techniques discovered by the inventors that can be used to implement the invention, and therefore can be considered preferred embodiments for implementing the invention. However, those skilled in the art should understand from this specification that many modifications can be made to the specific embodiments disclosed herein, still yielding the same or similar results, without departing from the spirit or scope of the invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and all materials disclosed herein and cited therein are incorporated herein by reference. Many equivalent techniques of specific embodiments of the invention described herein will be recognized or can be understood by ordinary experimentation by those skilled in the art. These equivalents will be included in the claims.

[0024] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0025] Example 1 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.2 mol / L sodium hydroxide solution. Perform hydrothermal etching treatment at 80 °C for 3 hours.

[0026] After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is about 7, and dry at 60 °C for 6 hours for later use.

[0027] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.1 mol oxalic acid, 0.05 mol ethanolamine and 0.02 mol EDTA, add them to 500 mL of deionized water and stir thoroughly until dissolved.

[0028] The dried honeycomb ceramic porous medium carrier was immersed in the modification solution, soaked in a water bath at 50 °C for 1 hour, and then removed and dried. The above soaking step was repeated 5 times to obtain the doped and modified porous medium carrier.

[0029] 3. Microwave-loaded metal ions Weigh 6.97 g of manganese acetate (Mn(CH3COO)2) and dissolve it in 100 mL of deionized water to prepare a 0.5 mol / L precursor solution.

[0030] The doped and modified porous medium carrier was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "on for 10 seconds / off for 20 seconds" and a power of 300W for a total heating time of 10 minutes.

[0031] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0032] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 550 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous Mn-based catalytic material for efficient removal of VOCs from industrial flue gas was obtained.

[0033] Example 2 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.3 mol / L sodium hydroxide solution. Perform hydrothermal etching at 70 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0034] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.05 mol tartaric acid, 0.05 mol glycine and 0.01 mol EDTA, add them to 500 mL of deionized water and stir thoroughly until dissolved.

[0035] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 3 times to obtain the doped and modified porous media support.

[0036] 3. Microwave-loaded metal ions Weigh 5.31 g of cobalt acetate ((CH3COO)2Co) and dissolve it in 100 mL of deionized water to prepare a 0.3 mol / L precursor solution.

[0037] The doped and modified porous medium carrier was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "on for 10 seconds / off for 20 seconds" and a power of 300W for a total heating time of 10 minutes.

[0038] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0039] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 500 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous media Co-based catalyst material for efficient removal of VOCs from industrial flue gas was obtained.

[0040] Example 3 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.1 mol / L potassium hydroxide solution. Perform hydrothermal etching at 65 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is about 7. Dry at 60 °C for 6 hours for later use.

[0041] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.1 mol oxalic acid, 0.05 mol triethanolamine and 0.02 mol EDTA, add them to 500 mL of deionized water and stir thoroughly until dissolved.

[0042] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 4 times to obtain the doped and modified porous media support.

[0043] 3. Microwave-loaded metal ions Weigh 2.56 g of yttrium acetate (C6H17O10Y) and dissolve it in 100 mL of deionized water to prepare a 0.1 mol / L precursor solution.

[0044] The doped and modified porous medium carrier was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "on for 10 seconds / off for 20 seconds" and a power of 300W for a total heating time of 12 minutes.

[0045] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0046] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 600 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous media Y-based catalyst material for efficient removal of VOCs from industrial flue gas was obtained.

[0047] Example 4 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.1 mol / L potassium hydroxide solution. Perform hydrothermal etching at 65 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is about 7. Dry at 60 °C for 6 hours for later use.

[0048] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.2 mol malic acid, 0.05 mol ethanolamine and 0.01 mol EDTA, add them to 500 mL of deionized water and stir thoroughly until dissolved to obtain the modification solution.

[0049] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated twice to obtain the doped and modified porous media support.

[0050] 3. Microwave-loaded metal ions Weigh 3.72 g of zirconium acetate ((CH3COO)4Zr) and dissolve it in 100 mL of deionized water to prepare a 0.1 mol / L precursor solution.

[0051] The doped and modified porous medium carrier was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "on for 10 seconds / off for 20 seconds" and a power of 300W for a total heating time of 20 minutes.

[0052] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0053] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 450 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous media Zr-based catalyst material for efficient removal of VOCs from industrial flue gas was obtained.

[0054] Example 5 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.3 mol / L sodium hydroxide solution. Perform hydrothermal etching at 80 °C for 4 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0055] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.2 mol tartaric acid, 0.05 mol triethanolamine and 0.02 mol EDTA, add them to 500 mL of deionized water and stir thoroughly until dissolved.

[0056] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 4 times to obtain the doped and modified porous media support.

[0057] 3. Microwave-loaded metal ions 1.76 g of nickel acetate ((CH3COO)2Ni) was weighed and dissolved in 100 mL of deionized water to prepare a 0.1 mol / L precursor solution. The doped and modified porous medium support was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "10 seconds on / 20 seconds off" and a power of 300W for a total heating time of 10 minutes.

[0058] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0059] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 650 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous media Ni-based catalyst material for efficient removal of VOCs from industrial flue gas was obtained.

[0060] Example 6 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.3 mol / L sodium hydroxide solution. Perform hydrothermal etching at 80 °C for 4 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0061] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.2 mol tartaric acid, 0.05 mol triethanolamine and 0.02 mol EDTA, add them to 500 mL of deionized water and stir thoroughly until dissolved.

[0062] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 5 times to obtain the doped and modified porous media support.

[0063] 3. Microwave-loaded metal ions 3.46 g of manganese acetate (Mn(CH3COO)2) was weighed and dissolved in 100 mL of deionized water to prepare a 0.2 mol / L precursor solution. The doped and modified porous media support was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "10 seconds on / 20 seconds off" and a power of 300 W for a total heating time of 5 minutes.

[0064] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0065] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 500 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous Mn-based catalytic material for efficient removal of VOCs from industrial flue gas was obtained.

[0066] Example 7 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a NaOH / KOH mixture (0.2 mol / L, molar ratio 1:1). Perform hydrothermal etching at 80 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0067] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.2 mol citric acid, 0.1 mol triethanolamine and 0.05 mol EDTA, add them to 500 mL deionized water and stir thoroughly until dissolved to obtain the modification solution.

[0068] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 3 times to obtain the doped and modified porous media support.

[0069] 3. Microwave-loaded metal ions A precursor solution was prepared by dissolving 0.15 mol / L each of nickel acetate ((CH3COO)2Ni) and manganese acetate ((CH3COO)2Mn) in 100 mL of deionized water.

[0070] The doped and modified porous medium carrier was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "on for 10 seconds / off for 20 seconds" and a power of 300W for a total heating time of 8 minutes.

[0071] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0072] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 600 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous media NiMn-based catalyst material for efficient removal of VOCs from industrial flue gas was obtained.

[0073] Example 8 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a NaOH / KOH mixture (0.2 mol / L, molar ratio 1:1). Perform hydrothermal etching at 80 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0074] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.1 mol citric acid, 0.1 mol oxalic acid, 0.05 mol glycine and 0.02 mol EDTA, add them to 500 mL of deionized water and stir thoroughly until dissolved.

[0075] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 3 times to obtain the doped and modified porous media support.

[0076] 3. Microwave-loaded metal ions A precursor solution was prepared by dissolving 0.1 mol / L each of zirconium acetate ((CH3COO)4Zr) and cobalt acetate ((CH3COO)2Co) in 100 mL of deionized water. The doped and modified porous media support was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "10 seconds on / 20 seconds off" and a power of 300W for a total heating time of 15 minutes.

[0077] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0078] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 550 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous media ZrCo-based catalyst material for efficient removal of VOCs from industrial flue gas was obtained.

[0079] Comparative Example 1 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.2 mol / L sodium hydroxide solution. Perform hydrothermal etching at 80 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0080] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.1 mol of nitric acid and add it to 500 mL of deionized water. Stir thoroughly until dissolved to obtain the modification solution.

[0081] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 4 times to obtain the doped and modified porous media support.

[0082] 3. Microwave-loaded metal ions Weigh 6.97 g of manganese acetate (Mn(CH3COO)2) and dissolve it in 100 mL of deionized water to prepare a 0.5 mol / L precursor solution.

[0083] The doped and modified porous medium carrier was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "on for 10 seconds / off for 20 seconds" and a power of 300W for a total heating time of 10 minutes.

[0084] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0085] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 550 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the nitric acid-modified porous Mn-based catalytic material was obtained.

[0086] Comparative Example 2 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.1 mol / L sodium hydroxide solution. Perform hydrothermal etching at 80 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0087] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.2 mol of hydrochloric acid and add it to 500 mL of deionized water. Stir thoroughly until dissolved to obtain the modification solution.

[0088] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 5 times to obtain the doped and modified porous media support.

[0089] 3. Microwave-loaded metal ions Weigh 6.97 g of manganese acetate (Mn(CH3COO)2) and dissolve it in 100 mL of deionized water to prepare a 0.5 mol / L precursor solution.

[0090] The doped and modified porous medium carrier was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "on for 10 seconds / off for 20 seconds" and a power of 300W for a total heating time of 10 minutes.

[0091] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0092] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 550 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the hydrochloric acid-modified porous Mn-based catalytic material was obtained.

[0093] Comparative Example 3 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.1 mol / L sodium hydroxide solution. Perform hydrothermal etching at 80 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0094] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.2 mol of sulfuric acid and add it to 500 mL of deionized water. Stir thoroughly until dissolved to obtain the modification solution.

[0095] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 3 times to obtain the doped and modified porous media support.

[0096] 3. Microwave-loaded metal ions Weigh 6.97 g of manganese acetate (Mn(CH3COO)2) and dissolve it in 100 mL of deionized water to prepare a 0.5 mol / L precursor solution.

[0097] The doped and modified porous medium carrier was immersed in the precursor solution and subjected to microwave-assisted treatment in a microwave reactor with an intermittent mode of "on for 10 seconds / off for 20 seconds" and a power of 300W for a total heating time of 10 minutes.

[0098] 4. Inertial purging and drying The porous media carrier after microwave treatment was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0099] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 550 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the sulfuric acid-modified porous Mn-based catalytic material was obtained.

[0100] Comparative Example 4 1. Carrier etching treatment Weigh out a honeycomb ceramic porous medium carrier (10 mm × 10 mm × 10 mm) and place it in a 0.2 mol / L sodium hydroxide solution. Perform hydrothermal etching at 80 °C for 3 hours. After removal, wash twice with anhydrous ethanol, then wash with deionized water until the pH of the washing solution is approximately 7. Dry at 60 °C for 6 hours for later use.

[0101] 2. Additive doping and modification Preparation of the modification solution: Weigh 0.1 mol oxalic acid, 0.05 mol ethanolamine and 0.02 mol EDTA, add them to 500 mL of deionized water and stir thoroughly until dissolved to obtain the modification solution.

[0102] The dried porous media support was immersed in the modification solution, soaked in a 50 °C water bath for 1 hour, and then removed and dried. The above steps were repeated 4 times to obtain the doped and modified porous media support.

[0103] 3. Metal ion impregnation loading Weigh 6.97 g of manganese acetate (Mn(CH3COO)2) and dissolve it in 100 mL of deionized water to prepare a 0.5 mol / L precursor solution.

[0104] The doped and modified porous medium support was immersed in the precursor solution and allowed to stand for 30 minutes.

[0105] 4. Inertial purging and drying After settling, the porous medium carrier was removed, and the pores were purged with high-purity nitrogen for 10 minutes to remove residual solution. Then it was dried at 80 °C for 10 hours.

[0106] 5. Atmosphere-controlled calcination The dried porous media support was placed in an atmosphere furnace and calcined at 550 °C for 3 hours under the condition of passing through a 5 vol.% O2 / N2 mixed gas. After cooling, the porous Mn-based catalytic material for efficient removal of VOCs from industrial flue gas was obtained.

[0107] SEM analysis was performed on the catalysts obtained in Example 1 and Comparative Examples 1-4, and the results are shown in the figure below. Figures 1-6 As shown; where, Figure 1 The image shows the SME diagram of the porous media material in Example 1 after pretreatment with a modification solution containing organic acid. Figure 2 This is a SEM image of the porous Mn-based catalytic material in Example 1; Figures 3-6 The images show SEM images of the porous Mn-based catalytic materials in Comparative Examples 1-4.

[0108] Depend on Figure 2 and Figure 3-6 The comparison reveals that the porous Mn-based catalytic material prepared by this invention has larger catalyst particles on its surface and a more uniform distribution.

[0109] The catalytic activity of the Mn-based porous media catalytic materials obtained in Example 1 and Comparative Examples 1-4 was evaluated using the following method: the catalyst activity evaluation was carried out in a fixed-bed reactor with toluene as the probe molecule. The amount of catalyst used was 1 g, the toluene concentration was 100 ppm, the remainder was air, and the gas flow rate was 200 mL / min. The reaction tail gas was detected and analyzed by gas chromatography.

[0110] The evaluation results of the above catalysts are shown in Table 1 and below. Figure 7 As shown.

[0111] Table 1. T90 temperature and toluene conversion rate at 250 °C for the materials in Example 1 and Comparative Examples 1-4.

[0112] The results showed that the Mn-based catalyst prepared in Example 1 had a lower toluene degradation temperature than the comparative example. The inorganic modification solution showed better toluene catalytic oxidation ability. With microwave loading, the low-temperature catalytic activity of the catalyst for toluene was effectively improved. The catalytic T90 temperature was below 210 °C, and the catalytic conversion rate of toluene reached 99% at 250 °C.

[0113] Examples 1-8 were prepared by impregnation and loading with different metal ions, and the T90 temperature and toluene conversion rate at 250 °C of the catalysts are shown in Table 2 below.

[0114] Table 2 shows the T90 temperature and toluene conversion rate at 250 °C for the materials in Examples 1-8.

[0115] The results showed that catalysts supported solely on Mn and Co exhibited lower T90 catalytic temperatures and higher toluene conversion rates compared to catalysts supported solely on other metal ions. In summary, supporting Mn and Co contributes to improving the low-temperature catalytic activity of the catalysts. The combined support of multiple different metals also contributes to enhancing the low-temperature catalytic activity of the catalysts.

[0116] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by this application.

Claims

1. A method for preparing a porous medium catalyst for efficient degradation of VOCs, characterized by, The method comprises the following steps: S1, placing the porous medium material in a dilute alkali solution, removing surface impurities and etching a microporous structure by hydrothermal treatment, and then washing with ethanol and deionized water alternately to neutralize after taking out, and drying; S2, soaking the porous medium material obtained in S1 in a modification solution containing an organic acid, an organic amine and a chelating agent, drying after water bath immersion, and repeating the water bath immersion step 2-5 times to obtain a doped and modified porous medium carrier; S3, soaking the doped and modified porous medium carrier in S2 in a precursor solution, promoting rapid diffusion of metal ions into the pores by intermittent microwave heating; then using inert gas to blow off the excess solution and drying at low temperature; S4, placing the dried porous medium carrier in S3 in an atmosphere furnace, calcining in an environment with 5% O2 / N2 mixed gas to obtain a porous medium catalyst.

2. The method of claim 1, wherein the porous medium catalyst for efficient degradation of VOCs is prepared by the steps of: In step S1, the dilute alkali solution is NaOH and / or KOH, and the concentration is 0.1-0.3 mol / L.

3. The method for preparing a porous media catalyst for efficient VOCs degradation according to claim 1, characterized in that, In step S1, the hydrothermal treatment temperature is 60-80 ℃, and the treatment time is 2-4 hours.

4. The method of claim 1, wherein the porous medium catalyst for efficient degradation of VOCs is prepared by the steps of: In step S2, the organic acid includes one or more of oxalic acid, citric acid, tartaric acid, malic acid, and glycine.

5. The method of claim 1, wherein the porous medium catalyst for efficient degradation of VOCs is prepared by the steps of: In step S2, the organic amine and the chelating agent include one or more of ethanolamine, triethanolamine, and ethylenediaminetetraacetic acid.

6. The method of claim 1, wherein the porous medium catalyst for efficient degradation of VOCs is prepared by the steps of: In step S2, the concentration of the organic acid, the organic amine and the chelating agent in the modification solution is 0.01-0.5 mol / L.

7. The method of claim 1, wherein the porous medium catalyst is prepared by the steps of: a) providing a porous medium; b) coating the porous medium with a first catalyst layer; c) coating the first catalyst layer with a second catalyst layer; and d) coating the second catalyst layer with a third catalyst layer. In step S3, the active metal source includes one of manganese acetate and cobalt acetate, or a combination of one of manganese acetate and cobalt acetate with one of zirconium acetate and nickel acetate.

8. The method of claim 6, wherein the porous medium catalyst for efficient degradation of VOCs is prepared by the steps of: In step S3, the concentration of the precursor solution is 0.1-0.5 mol / L.

9. The method of claim 1, wherein the porous medium catalyst is prepared by the steps of: a) providing a porous medium; b) coating the porous medium with a first catalyst layer; c) coating the first catalyst layer with a second catalyst layer; and d) coating the second catalyst layer with a third catalyst layer. In step S3, the intermittent microwave heating treatment conditions are 300W, 10 seconds on / 20 seconds off, and the cumulative time is 5-20 minutes.

10. The method of claim 1, wherein the porous medium catalyst is prepared by the steps of: a) providing a porous medium; b) coating the porous medium with a first catalyst layer; c) coating the first catalyst layer with a second catalyst layer; and d) coating the second catalyst layer with a third catalyst layer. In step S4, the calcination temperature of the porous medium catalyst is 450-650 ℃, and the calcination time is 2-4 hours.

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