Preparation method and application of manganese-based spinel monolithic catalyst

Abstract

The invention belongs to the technical field of catalysts, and relates to a preparation method and application of a manganese-based spinel monolithic catalyst. The method comprises the following steps: mixing a binder and a solvent to obtain a colloidal solution, uniformly mixing Mn (OH) 2, raw bauxite and activated carbon to obtain a mixture, and mixing the colloidal solution and the mixture to obtain mud; transferring the mud into a mold, and then putting the whole mold into water for phase inversion molding; the manganese-based spinel monolithic catalyst is prepared by the following steps: preparing a manganese-based spinel monolithic catalyst, demolding, drying, calcining to obtain the manganese-based spinel monolithic catalyst, and finally further performing alkali etching to obtain the high-activity manganese-based spinel monolithic catalyst. A phase inversion molding-calcining process is adopted, Mn (OH) 2 is directly mixed with raw bauxite and activated carbon, an integrated spinel structure is formed after calcining, the structural stability of the catalyst is remarkably improved, and the catalytic efficiency is further improved through alkali treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts and relates to a preparation method and application of a manganese-based spinel monolithic catalyst. Background Art

[0002] Controlling the emission of volatile organic compounds (VOCs) in industrial processes is an important task in the prevention and control of air pollution. Catalytic oxidation is a promising VOC treatment technology that mainly relies on highly active catalysts in practical applications. Manganese-based spinels such as Mn3O4, MnAl2O4 and CuMn2O4 are widely used in the catalytic oxidation of VOCs due to their high catalytic activity, synergistic effect and thermal / structural stability. For example, Mn3O4-HNS catalyst has a high surface active oxygen content, rich Mn 4+ The catalyst exhibits excellent stability and low-temperature reducibility, demonstrating good ethanol combustion activity. The abundant oxygen vacancies and strong reducibility of the Mn3O4 catalyst enable a significant low-temperature oxidation of methyl ethyl ketone. While manganese-based spinels possess high catalytic activity, they are typically powdered catalysts in practical applications, making them unsuitable for VOC purification. Therefore, the development of monolithic manganese-based spinel catalysts is necessary.

[0003] On the other hand, to date, monolithic catalysts have been widely used in the catalytic oxidation of VOCs due to their advantages such as structural geometry, low pressure drop, and large specific surface area. Common types include ceramic-based monolithic catalysts, metal-based monolithic catalysts, and mixed or composite monolithic catalysts. Most monolithic catalysts are usually coated with active ingredients on the surface of the carrier. Among them, coating precious metals or transition metal oxides on the surface of ceramics (cordierite and Al2O3) has been widely studied and used for VOCs. For example, Zhou et al. (Zhou, J., et al., Enhanced Catalytic Combustion Performance of Toluene over a Novel Co-CeO x Monolith Catalyst.Energy&Fuels,2021.35(7):p.6190-6201) reported that Co-CeO xThe active components are coated on a cordierite support to form a monolithic catalyst, which has good catalytic activity for toluene oxidation. Dai et al. (Dai, Y., et al., Catalytic combustion of toluene over cerium modified CuMn / Al2O3 / cordierite monolithic catalyst. Journal of Fuel Chemistry and Technology, 2024. 52 (1): p. 55-64) proposed the use of ultrasonic-assisted impregnation to prepare a CuMnCe2 / Al2O3 / cordierite monolithic catalyst, which also showed high catalytic activity for toluene combustion. Although these monolithic catalysts show excellent catalytic performance for the degradation of VOCs, most catalysts still have the disadvantages of uneven coating or easy loss of active components, resulting in decreased catalytic activity.

[0004] In order to solve these problems, the preparation of manganese-based spinel monolithic catalysts after mixing the supporting material and the active material can make up for these shortcomings. So far, manganese-based spinel is usually also loaded on a carrier to form a monolithic catalyst, such as Mn3O4 / cordierite monolithic catalyst (Piumetti, M., D.Fino, and N.Russo, Mesoporous manganese oxides prepared by solution combustion synthesis as catalysts for the total oxidation of VOCs. Applied Catalysis B: Environmental, 2015.163: p.277-287.) and Co 3-x Mn x O4 / Ni foam monolithic catalyst (Jiang, X., et al., Integral structured Co-Mn composite oxides grown on interconnected Ni foam for catalytic toluene oxidation. RSC Advances, 2019.9 (12): p. 6533-6541). Therefore, in the monolithic catalyst, the monolithic catalyst in which both the carrier and the active material include manganese-based spinel is rarely reported. However, this monolithic catalyst greatly increases the preparation cost and is not suitable for practical application. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a preparation method and application of a manganese-based spinel monolithic catalyst to overcome the shortcomings of the prior art.

[0006] One object of the present invention is achieved through the following technical solutions:

[0007] A method for preparing a manganese-based spinel monolithic catalyst comprises the following steps:

[0008] Mixing a binder and a solvent to obtain a colloidal solution, uniformly mixing Mn(OH)2, raw bauxite, and activated carbon to obtain a mixture, and mixing the colloidal solution and the mixture to obtain a sludge;

[0009] The sludge is transferred to a mold, and the entire mold is then placed in water for phase inversion molding;

[0010] The mold is demoulded, dried, and then calcined to obtain a monolithic catalyst.

[0011] The binder and the solvent are mixed to obtain a colloidal solution, Mn(OH)2, raw bauxite, and activated carbon are mixed uniformly to obtain a mixture, and the colloidal solution and the mixture are mixed to obtain a sludge. The above mixing method is preferably ball milling.

[0012] Preferably, the mass ratio of the solvent to the binder is 2 to 10:1.

[0013] Preferably, the binder is a combination of one or more of polyethersulfone, polysulfone, phenolic resin, epoxy resin, polyvinylpyrrolidone, and polyvinyl alcohol. The binder is mixed with the raw materials to form a slurry. After injection molding, the binder solidifies (phase inversion) upon contact with water, thereby forming a solidified green body. After calcination, the binder is burned off, and it also acts as a pore-forming agent.

[0014] More preferably, the binder is polyethersulfone and polyvinylpyrrolidone.

[0015] Preferably, the solvent is a combination of one or more of N-methylpyrrolidone, N-ethylpyrrolidone, dimethylacetamide, dimethylformamide and dimethyl sulfoxide.

[0016] Preferably, the mass ratio of Mn(OH)2, raw bauxite and activated carbon is 1:2-5:0.8-2.

[0017] Preferably, the element contents in raw bauxite include: Al: 40-45wt%, Si: 38-42wt%, Fe: 4-6wt%, Ti: 3-5wt%, K: 3-5wt%, Ca: 2-4wt%, and the others are inevitable impurities and / or trace elements.

[0018] Trace elements include one or more of gallium (Ga), germanium (Ge), niobium (Nb), tantalum (Ta), scandium (Sc), vanadium (V), phosphorus (P), chromium (Cr), nickel (Ni), and the like.

[0019] Preferably, the D50 of Mn(OH)2 is 10 to 100 μm, the D50 of raw bauxite is 5 to 50 μm, and the D50 of activated carbon is 5 to 80 μm.

[0020] Preferably, the mass ratio of the colloidal solution to the mixture is 1:1-4.

[0021] Preferably, the entire mold is placed in water for 5 to 50 hours, more preferably for 10 to 40 hours.

[0022] Preferably, the drying temperature is 80-95° C., and the drying time is 2-10 hours.

[0023] Preferably, the calcination temperature is 550-750° C., and the calcination time is 1-5 hours.

[0024] Preferably, the preparation method further comprises the following step: immersing the monolithic catalyst in an alkaline solution for 2 to 60 minutes.

[0025] The alkaline solution may be one or more of a sodium hydroxide solution, a potassium hydroxide solution, an ammonia solution, and a sodium bicarbonate solution.

[0026] Preferably, the concentration of the alkaline solution is 0.05 to 5 mol / L, more preferably 0.5 to 2 mol / L.

[0027] The monolithic catalyst of the present invention is prepared by a phase conversion molding-calcination process. The preparation process is shown in Figure 1 shown.

[0028] The second object of the present invention is achieved through the following technical solutions:

[0029] A manganese-based spinel monolithic catalyst is prepared by the above preparation method.

[0030] Preferably, the monolithic catalyst is cylindrical and has 10 to 100 axial channels thereon, and the axial channels penetrate the front and rear surfaces of the cylinder.

[0031] The height of the monolithic catalyst can be 0.5 to 100 cm, and is further preferably 1 to 10 cm.

[0032] The diameter of the monolithic catalyst can be 0.5 to 100 cm, preferably 1 to 10 cm.

[0033] Preferably, the channels are cylindrical, and the diameter of each channel is 0.05 to 1 cm.

[0034] Preferably, the specific surface area of ​​the monolithic catalyst is 10 to 50 m 2 / g.

[0035] During the catalyst preparation process, the shape of the mold used corresponds to that of the monolithic catalyst. The mold has a lower bottom surface, which, together with the mold's side surfaces, forms a cylindrical cavity (the mold's side inner walls form the cylindrical sides of the cavity). The lower bottom surface has several through-holes, the number of which corresponds to the catalyst's axial passages. Stainless steel rods are inserted into the through-holes, extending axially through the through-holes toward the cylindrical cavity. The length of the rod above the through-holes corresponds to the height of the catalyst. A sludge is poured into the mold cavity, and then the entire mold is placed in water for phase inversion molding to form a green compact of a specific shape.

[0036] The third object of the present invention is achieved through the following technical solutions:

[0037] Application of the manganese-based spinel monolithic catalyst in catalytic degradation of volatile organic compounds.

[0038] When the volatile organic compound is acetone, the catalyst's T 50 ≤320℃, T 90 ≤380℃, T 50 and T 90 It refers to the reaction temperature at which the conversion rate of acetone is 50% and 90%.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention adopts a phase transformation molding-calcination process to directly mix Mn(OH)2 with raw bauxite and activated carbon, avoiding the problems of easy shedding of active components and uneven coating in traditional coating methods; after calcination, an integrated spinel structure (MnAl2O4, Mn3O4) is formed, and the carrier and active components are deeply combined, which significantly improves the structural stability and catalytic efficiency of the catalyst.

[0041] 2. This invention uses raw bauxite and Mn(OH)2 as primary raw materials, replacing precious metals or complex synthetic supports, significantly reducing preparation costs. Furthermore, activated carbon, acting as a pore-forming and reducing agent, forms a porous structure during calcination, exposing more active sites and synergistically improving the efficiency of catalytic oxidation of VOCs.

[0042] 3. The monolithic catalyst is treated by immersion in an alkaline solution to etch part of the crystal phase and regulate the pore structure. This treatment effectively dissolves catalytically inactive substances and increases oxygen vacancies, thereby improving the efficiency of catalytic oxidation of VOCs and reducing the T of VOCs conversion. 50 、T 90 temperature.

[0043] 4. The present invention utilizes a simple method of mixing a colloidal solution with a powder mixture to achieve solid-phase molding in water. A cylindrical monolithic catalyst with axial channels is prepared using a mold. The activated carbon decomposes during calcination to form abundant micropores, which synergize with the axial channels to achieve efficient contact between reactants and the catalyst, improving catalytic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the preparation of the monolithic catalyst;

[0045] Figure 2 is the SEM image of the powder raw material;

[0046] Figure 3 Thermogravimetric diagram of raw material raw bauxite;

[0047] Figure 4 Thermogravimetric diagram of raw material manganese hydroxide;

[0048] Figure 5 This is the particle size distribution diagram of raw bauxite, manganese hydroxide, and activated carbon;

[0049] Figure 6 This is a particle size distribution diagram after the powder raw materials are mixed according to the proportions of Example 1;

[0050] Figure 7 Actual images and dimensions of the monolithic catalysts prepared in Examples 1 and 3;

[0051] Figure 8 is the XRD pattern of the monolithic catalyst of Examples 1-4;

[0052] Figure 9 (a) Nitrogen adsorption / desorption curves and (b) pore size distribution diagrams of the monolithic catalysts of Examples 1-4;

[0053] Figure 10 Graph showing the catalytic oxidation performance of the monolithic catalysts of Examples 1-4 for acetone. DETAILED DESCRIPTION

[0054] Below by specific embodiment and accompanying drawing, technical scheme of the present invention is further described explanation, it should be understood that specific embodiment described herein is only for helping to understand the present invention, is not used for specific limitation of the present invention.And accompanying drawing used herein, is only for better illustrating the disclosure of the present invention, does not have limiting effect on protection scope.If no special instructions, the raw materials adopted in the embodiment of the present invention are all raw materials commonly used in this area, and the method adopted in the embodiment is all conventional method in this area.

[0055] Figure 2The SEM images of raw bauxite, manganese hydroxide and activated carbon are shown below. Figure 3 Thermogravimetric diagram of raw material raw bauxite, Figure 4 Thermogravimetric diagram of raw material manganese hydroxide, Figure 5 This is the particle size distribution diagram of raw bauxite, manganese hydroxide, and activated carbon. Figure 6 This is a particle size distribution diagram after the powder raw materials are mixed according to the proportions of Example 1. Table 1 lists the specific values ​​of the particle size distribution of raw bauxite, manganese hydroxide, activated carbon and the mixture.

[0056] Table 1 Particle size data of raw bauxite, manganese hydroxide, activated carbon and their mixtures

[0057]

[0058] The element contents of the raw bauxite used in the following examples are shown in Table 2:

[0059] Table 2 XRF test results of raw bauxite (wt.%)

[0060]

[0061] Example 1

[0062] Take polyethersulfone (24g), polyvinylpyrrolidone (9g), N-methylpyrrolidone (100g) and zirconium oxide balls and put them into a polytetrafluoroethylene ball mill. Use a planetary ball mill to mix them to obtain a uniform colloidal solution. Put Mn(OH)2 (46g), raw bauxite (138g) and activated carbon powder (46g) and zirconium oxide balls into a ball mill and use a drum ball mill to evenly mix the three powders. The above colloidal solutions and powders are further placed in a drum ball mill to fully mix to form a muddy solid. Then transfer it to a mold, and then put the entire mold into water for 24h for phase inversion molding. After demolding, dry it at 90℃ for 6h, and then calcine it at 650℃ for 2h to obtain a monolithic catalyst named BTMn.

[0063] The shape of the monolithic catalyst prepared in Example 1 is as follows Figure 7 As shown, the monolithic catalyst is cylindrical and has 64 axial channels, which extend through the front and back surfaces of the cylinder to form through-holes. The monolithic catalyst is 3 cm tall and 3 cm in diameter, and each channel is cylindrical and has a diameter of 0.15 cm.

[0064] Example 2

[0065] The difference between Example 2 and Example 1 is that Example 2 subsequently adopts NaOH solution immersion treatment:

[0066] The BTMn monolithic catalyst prepared in Example 1 was immersed in a 0.25 mol / L NaOH solution (completely covering the monolithic catalyst) for 30 minutes, and then dried to obtain a catalyst named BTMn-0.25OH.

[0067] Example 3

[0068] The difference between Example 3 and Example 2 is that the concentration of the NaOH solution in Example 3 is 1 mol / L, and the obtained catalyst is named: BTMn-OH.

[0069] Example 4

[0070] The difference between Example 4 and Example 1 is that the concentration of the NaOH solution in Example 4 is 1.75 mol / L, and the obtained catalyst is named: BTMn-1.75OH.

[0071] Figure 8 The XRD patterns of the monolithic catalysts prepared in Examples 1-4 show that, in addition to Al2O3 (PDF#73-1512) and Al2SiO5 (PDF#74-1976), a manganese-based spinel phase is also present in the monolithic catalysts. New diffraction peaks at 36.3°, 44.6°, and 58.8° are attributed to the

[311] ,

[400] , and

[511] crystal planes of the MnAl2O4 phase (PDF#29-0880); and new diffraction peaks at 18.0°, 32.3°, 51.0°, 60.7°, and 64.6° are attributed to the

[101] ,

[103] ,

[105] ,

[215] , and

[400] crystal planes of the Mn3O4 phase (PDF#80-0382). This indicates that the spinel phases Mn3O4 and MnAl2O4 were newly formed after mixing and calcining Mn(OH)2 with bauxite. The diffraction peak intensity of the monolithic catalyst decreased slightly after alkali treatment, indicating that the alkali treatment etched part of the crystal phase.

[0072] Table 3 Specific surface area, pore volume and pore diameter of the catalysts prepared in Examples 1-4

[0073]

[0074] From Table 3 and Figure 9 It can be seen that with the increase of the concentration of NaOH solution, the specific surface area, pore volume and pore diameter of the catalyst increase accordingly.

[0075] Example 5

[0076] The difference between Example 5 and Example 3 is that Example 5 is calcined at 600° C. for 3 h. The rest is the same as Example 3, and a monolithic catalyst is obtained.

[0077] Example 6

[0078] The difference between Example 6 and Example 3 is that Example 6 is calcined at 700° C. for 2 h. The rest is the same as Example 3, to obtain a monolithic catalyst.

[0079] Example 7

[0080] Take polyethersulfone (20g), polyvinylpyrrolidone (12g), N-methylpyrrolidone (100g) and zirconium oxide balls and put them into a polytetrafluoroethylene ball mill, and use a planetary ball mill to mix them to obtain a uniform colloidal solution. Put Mn(OH)2 (40g), raw bauxite (120g) and activated carbon powder (45g) and zirconium oxide balls into a ball mill, and use a drum ball mill to evenly mix the three powders. These colloidal solutions and powders are further placed in a drum ball mill and fully mixed to form a muddy solid. Then transfer it to a mold, and then put the entire mold into water for 18h for phase inversion molding. After demolding, dry it at 80°C for 8h, and then calcine it at 620°C for 3h to obtain a monolithic catalyst;

[0081] The monolithic catalyst was immersed in a NaOH solution with a concentration of 0.85 mol / L (completely covering the monolithic catalyst) for 40 minutes, and then the obtained catalyst was dried.

[0082] Comparative Example 1

[0083] Comparative Example 1 differs from Example 1 in that no Mn(OH)2 is added, and raw bauxite (184 g), activated carbon powder (46 g), and zirconium oxide balls are placed in a ball mill for ball milling. Other procedures are the same as in Example 1.

[0084] Comparative Example 2

[0085] Comparative Example 2 differs from Example 1 in that no activated carbon powder is added. Instead, Mn(OH)2 (46 g), raw bauxite (184 g), and zirconia balls are placed in a ball mill for ball milling. Other steps are the same as in Example 1.

[0086] Comparative Example 3

[0087] The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 uses MnO2 instead of Mn(OH)2, and the rest is the same as Example 1.

[0088] Comparative Example 4

[0089] The difference between Comparative Example 4 and Example 1 is that Comparative Example 4 uses Mn3O4 instead of Mn(OH)2, and the rest is the same as Example 1.

[0090] No MnAl2O4 crystalline phase was observed in the XRD patterns of the catalysts prepared in Comparative Examples 1, 3, and 4. Since no Mn was added to Comparative Example 1, a manganese-based spinel phase naturally did not form. Comparative Examples 3 and 4, respectively, used MnO2 and Mn3O4 instead of Mn(OH)2. MnO2 and Mn3O4 are difficult to produce manganese-based spinel with aluminum hydroxide from bauxite.

[0091] The monolithic catalyst prepared in Examples 1-7 and Comparative Examples 1-4 was used to catalyze acetone. The test method was as follows: the total flow rate was 2.5 L·min -1 , acetone concentration is 0.05% (volume percentage), humidity is 50%, and reaction mass space velocity is 5000 mL·g -1 ·h -1 The reactor was a stainless steel tube with a diameter of 30 mm and a length of 600 mm. During each run, the monolithic catalyst was loaded into the stainless steel reactor and the reaction temperature was controlled by temperature programming. At each reaction temperature, the acetone concentration at the reactor inlet and outlet was measured by gas chromatography.

[0092] Acetone conversion rate (X acetone )calculate:

[0093]

[0094] [acetone] in is the acetone concentration at the reactor inlet, [acetone] out is the acetone concentration at the reactor outlet.

[0095] The test results are as follows Figure 10 As shown in Table 1:

[0096] Table 4 Catalytic performance of catalysts prepared in Examples and Comparative Examples for acetone

[0097]

[0098] *T 50 and T 90 It refers to the reaction temperature at which the conversion rate of acetone is 50% and 90%.

[0099] From Table 1 and Figure 10 It can be seen that in Comparative Example 1, Mn(OH)2 was not added, and the prepared catalyst catalyzed the T 50 and T 90 Temperature>400℃, the conversion effect is very poor; although the manganese source is added in Comparative Examples 3 and 4, no MnAl2O4 crystal phase is formed, which catalyzes the T 50 and T 90 The higher the temperature, the poorer the conversion effect.

[0100] Comparison of Examples 1-4 shows that treating the catalyst with an alkaline solution is beneficial for improving the catalytic activity for VOC oxidation. Furthermore, the alkaline treatment requires adjusting the alkaline concentration and treatment time to achieve a better catalytic effect.

[0101] The various aspects, embodiments, and features of the present invention should be considered in all respects as illustrative and not limiting, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0102] In the preparation method of the present invention, the order of the steps is not limited to the order listed. Persons skilled in the art will appreciate that variations in the order of the steps are within the scope of the present invention without inventive effort. Furthermore, two or more steps or actions may be performed simultaneously.

[0103] Finally, it should be noted that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit its implementation. Persons skilled in the art may make various modifications, additions, or substitute similar methods for the described specific embodiments. It is not necessary and impossible to provide comprehensive examples of all implementations here. However, obvious variations or modifications arising from the essential spirit of the present invention remain within the scope of protection of the present invention, and interpreting them as any additional limitations would be contrary to the spirit of the present invention.

Claims

1. A method for preparing a manganese-based spinel monolithic catalyst, characterized in that: The following steps are involved: Mixing a binder and a solvent to obtain a colloidal solution, uniformly mixing Mn(OH)2, raw bauxite, and activated carbon powder to obtain a mixture, and mixing the colloidal solution and the mixture to obtain a sludge; The sludge is transferred into a mold, and the entire mold is then placed in water for phase inversion molding; The mold is demoulded, dried, and then calcined to obtain a monolithic catalyst.

2. The preparation method according to claim 1, characterized in that The mass ratio of solvent to binder is 2 to 10:1; and / or, the mass ratio of Mn(OH)2, raw bauxite, and activated carbon is 1:2-5:0.8-2; And / or, the mass ratio of the colloidal solution to the mixture is 1:1-4.

3. The preparation method according to claim 1, characterized in that The binder is a combination of one or more of polyethersulfone, polysulfone, phenolic resin, epoxy resin, polyvinylpyrrolidone, and polyvinyl alcohol; and / or, the solvent is a combination of one or more of N-methylpyrrolidone, N-ethylpyrrolidone, dimethylacetamide, dimethylformamide and dimethyl sulfoxide; And / or, the element content in the raw bauxite includes: Al: 40-45wt%, Si: 38-42wt%, Fe: 4-6wt%, Ti: 3-5wt%, K: 3-5wt%, Ca: 2-4wt%, and the others are inevitable impurities and / or trace elements; And / or, the D50 of Mn(OH)2 is 10-100 μm, the D50 of raw bauxite is 5-50 μm, and the D50 of activated carbon is 5-80 μm.

4. The preparation method according to claim 1, characterized in that Place the entire mold in water for 5 to 50 hours; and / or, the drying temperature is 80-95° C. and the drying time is 2-10 hours; And / or, the calcination temperature is 550-750° C., and the calcination time is 1-5 hours.

5. The preparation method according to any one of claims 1 to 4, characterized in that The preparation method further comprises the following steps: placing the monolithic catalyst in an alkaline solution and immersing it for 2 to 60 minutes.

6. The preparation method according to claim 5, characterized in that The concentration of the alkaline solution is 0.05 to 5 mol / L.

7. A manganese-based spinel monolithic catalyst, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 6.

8. The manganese-based spinel monolithic catalyst according to claim 7, characterized in that: The monolithic catalyst is cylindrical and has 10 to 100 axial channels thereon, and the axial channels penetrate the front and rear surfaces of the cylinder.

9. Use of the manganese-based spinel monolithic catalyst according to claim 7 in catalytic degradation of volatile organic compounds.

10. The use according to claim 9, characterized in that When the volatile organic compound is acetone, the catalyst's T 50 ≤320℃, T 90 ≤380℃, T 50 and T 90 It refers to the reaction temperature at which the conversion rate of acetone is 50% and 90%.

Images