Preparation method of non-noble metal monolithic catalyst for purifying formaldehyde gas
By using a non-precious metal catalyst, manganese-cerium alloy, and specific binders to form a uniform coating on the surface of cordierite honeycomb ceramics, the problems of expensive catalysts and high powder shedding rate in air filters are solved, achieving a low-cost and high-efficiency formaldehyde purification effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-03
- Publication Date
- 2026-03-10
AI Technical Summary
The catalysts in existing air filters are expensive and have a high powder shedding rate, which affects the formaldehyde purification efficiency.
A non-precious metal catalyst, manganese-cerium alloy, was used, combined with polyacrylamide, hexadecyltrimethylammonium bromide, and polyether carboxylic acid as binders. A uniform and firm catalyst layer was formed on the surface of cordierite honeycomb ceramics through negative pressure coating and calcination processes.
It achieves low cost, low powder loss rate and high formaldehyde purification effect. The catalyst cost is reduced by 30-70%, the powder loss rate is ≤0.80%, and the formaldehyde removal rate can reach 90%.
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Figure CN121623779A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of air filter cartridges, in particular to a preparation method of a non-noble metal monolithic catalyst for purifying formaldehyde gas. BACKGROUND
[0002] At present, the situation of formaldehyde concentration exceeding the standard in indoor environment is very serious, and its release time can be as long as 10-15 years, which causes great harm to people's health. Formaldehyde has been upgraded to the first class carcinogen. Therefore, it has become an urgent task to improve people's living environment to study formaldehyde purification technology and effectively eliminate indoor formaldehyde pollution.
[0003] The existing indoor formaldehyde gas purification methods mainly include adsorption technology, photocatalytic technology and catalytic oxidation technology. The adsorption technology has the problem of secondary pollution, the photocatalytic technology needs ultraviolet excitation light source, and the catalytic oxidation technology has the advantages of no external excitation light source, mild reaction conditions (room temperature), clean product and good purification effect, so it has the widest application prospect.
[0004] At present, porous materials are mainly used as catalyst supporting substrates. Cordierite honeycomb ceramics have the advantages of regular pore structure, good thermal stability, low price and convenient processing and molding, and are one of the main skeleton matrices of supported noble metal monolithic catalysts for VOCs catalytic purification. However, the existing technology generally uses noble metal catalysts for formaldehyde purification, which has high economic cost. In addition, alumina coating is generally used to treat cordierite honeycomb ceramics before the catalyst surface is bonded, which has poor bonding effect, high powder dropping rate and affects the formaldehyde purification efficiency.
[0005] Therefore, it is necessary to develop an air filter cartridge (including a preparation method) with low cost, low powder dropping rate and high formaldehyde removal efficiency. SUMMARY
[0006] In view of the above analysis, the embodiments of the present application aim to provide an air filter cartridge for purifying formaldehyde and a preparation method thereof, which can solve at least one of the problems in the prior art, such as high cost of catalyst for purifying formaldehyde, high powder dropping rate and unsatisfactory formaldehyde removal effect.
[0007] The present application provides a preparation method of an air filter cartridge for purifying formaldehyde, comprising the following specific steps:
[0008] S1: weighing or measuring a non-noble metal catalyst and water, and mixing to prepare a non-noble metal catalyst slurry;
[0009] S2: adding a bonding aid to the non-noble metal catalyst slurry and mixing uniformly to obtain a mixed slurry;
[0010] S3: coating the mixed slurry in the porous material which is pre-processed by water immersion, drying and calcining to obtain the finished air filter element;
[0011] The binding aid contains polyacrylamide, cetyltrimethylammonium bromide and polyether carboxylic acid.
[0012] Specifically, the non-noble metal catalyst is a manganese-cerium alloy.
[0013] Specifically, the effective mass concentration of the non-noble metal catalyst in the non-noble metal catalyst slurry in step S1 is 10-30%, and the rest is water.
[0014] Specifically, the specific parameters of the binding aid in step S2 are as follows:
[0015] 0.05-0.1% of a polyacrylamide solution by mass of the non-noble metal catalyst slurry, wherein the relative molecular weight of the polyacrylamide is 3 million, and the effective mass concentration of the polyacrylamide is ≥90%;
[0016] 0.1-0.3% of cetyltrimethylammonium bromide powder by mass of the non-noble metal catalyst slurry;
[0017] 0.1-1.0% of a polyether carboxylic acid solution by mass of the non-noble metal catalyst slurry, wherein the effective mass concentration of the polyether carboxylic acid solution is ≥70%.
[0018] Preferably, the porous material is cordierite honeycomb ceramic, and the pore density is 200-600 mesh.
[0019] Preferably, the cordierite honeycomb ceramic is pre-processed by being immersed in water for 0.5-1 h before step S3 to activate the surface hydroxyl groups, which helps the non-metal slurry mixing system to be uniformly coated on the surface.
[0020] Specifically, the specific operation of coating in step S3 is as follows: the porous material is sleeved into one end of a rubber tube, and the other end is connected to a negative pressure device, the negative pressure pressure is controlled to be 60-80 kpa, and the extraction time is 5-15 s; wherein the mass ratio of the mixed slurry to the porous material is 1-2:10.
[0021] Specifically, the drying temperature in step S3 is 100-110°C, and the drying time is 2-3 h.
[0022] Specifically, the calcining temperature in step S3 is 500-650°C, and the calcining time is 2-3 h.
[0023] The application further discloses an air filter element prepared by the preparation method.
[0024] Specifically, the powder dropping rate of the air filter element is ≤0.80%.
[0025] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:
[0026] 1、 The air filter element catalyst provided by the present application is uniformly distributed, firmly bonded, and has low powder loss rate.
[0027] The present application adopts a non-noble metal catalyst (manganese-cerium alloy), the surface of which has hydrophobic properties, while the surface of the cordierite honeycomb ceramic has hydrophilic properties. The present application particularly selects polyacrylamide, cetyltrimethylammonium bromide, and polyether carboxylic acid mixed adhesion aids for preparing catalyst slurry, and optimizes the specific content thereof through theoretical design and experimental adjustment, so that the catalyst slurry can firmly bond the catalyst to the surface of the porous material (cordierite honeycomb ceramic).
[0028] Specifically, polyacrylamide, cetyltrimethylammonium bromide, and polyether carboxylic acid can all be regarded as amphiphilic substances with hydrophilic / lipophilic groups. The present application utilizes the hydrophilicity of the amphiphilic organic substance to allow the adhesion aid to be uniformly loaded on the surface of the cordierite honeycomb ceramic, exposing the hydrophobic tail, which attracts the hydrophobic non-noble metal catalyst to combine therewith, thereby realizing strong combination of the non-noble metal and the cordierite honeycomb ceramic and achieving the beneficial effect of low powder loss rate.
[0029] It is worth emphasizing that in the present application, the higher the loading amount of the formaldehyde removal catalyst is not necessarily better, but rather, under the premise of ensuring formaldehyde removal efficiency, the loading amount of the catalyst should be as low as possible. Based on the dispersion effect of the mixed adhesion aid and in combination with the negative pressure adsorption process, the present application can realize low loading rate of the non-noble metal and avoid plugging of the pore channels of the cordierite honeycomb ceramic under the premise of ensuring catalytic performance, thereby laying a foundation for cost control in mass production and realizing low air resistance in actual use.
[0030] 2、 The present application adopts a non-noble metal catalyst (manganese-cerium alloy), which is low in price and has good formaldehyde removal effect. The manganese-cerium alloy used in the present application has excellent formaldehyde removal performance under normal temperature and humidity conditions. Figure 1 The formaldehyde removal test results of the formaldehyde removal cordierite (porous material) prepared by the method of the present application show that in 3 parallel tests, the formaldehyde removal cordierite all exhibits excellent formaldehyde removal performance, with a formaldehyde removal rate of about 40% in 2 minutes, a formaldehyde removal rate of ≥80% in 18 minutes, and a maximum of 90%.
[0031] The cost of the manganese-cerium alloy catalyst of the present application is about 120-150 yuan / kg, while the price of the commonly used noble metal catalyst on the market is about 350-390 yuan / kg, so the cost advantage of the present application is great. In addition, the formaldehyde removal cordierite prepared by the present application has the possibility of mass production, and its process is simple, repeatable, has excellent performance, and the production cost is controllable, so the comprehensive cost advantage is greater.
[0032] 3. The raw materials and equipment involved in this invention are common and readily available, and the preparation process is simple. There is no need to make an alumina coating, which shortens the production / process cycle, has low operation difficulty, and is suitable for large-scale production and large-scale promotion.
[0033] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description
[0034] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.
[0035] Figure 1 The graphs show the relationship between the formaldehyde removal rate and time for the formaldehyde-removing cordierite in Examples 1-3.
[0036] Figure 2 Schematic diagram of a frame used for formaldehyde removal testing of air filters;
[0037] Figure 3 A schematic diagram of the assembly status for formaldehyde removal testing of an air filter element;
[0038] Figure 4 A flowchart of the manufacturing process for air filter elements (including corresponding equipment). Detailed Implementation
[0039] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.
[0040] This invention provides a method for preparing an air filter element for purifying formaldehyde, comprising the following specific steps:
[0041] S1: Weigh or measure the non-precious metal catalyst and water, and mix them to prepare a non-precious metal catalyst slurry.
[0042] S2: Add a binder to the non-precious metal catalyst slurry and mix evenly to obtain a mixed slurry;
[0043] S3: The mixed slurry is coated onto a porous material that has been pre-treated with water, and then dried and calcined to obtain the finished air filter element;
[0044] The adhesive additive contains polyacrylamide, cetyltrimethylammonium bromide, and polyether carboxylic acid.
[0045] Specifically, the non-noble metal catalyst is a manganese-cerium alloy, and the mass ratio of manganese oxide, cerium oxide and graphite powder in the manganese-cerium alloy is 2:1:30, wherein the manganese oxide is manganese dioxide with a particle size of 400 mesh, the cerium oxide is cerium oxide with a particle size of 400 mesh, and the graphite powder has a particle size of 400 mesh. The above alloy has good aldehyde removal effect.
[0046] Specifically, the manganese-cerium alloy can be prepared according to the prior art: manganese dioxide with a particle size of 400 mesh, cerium oxide with a particle size of 400 mesh and graphite powder are mixed in a mass ratio of 2:1:30, the obtained mixture is dried at 120°C for 12h, and then filled into an empty graphite rod, the graphite rod is inserted into the positive clamp of an electric arc furnace, the electric arc furnace is subjected to negative pressure and filled with nitrogen inert gas, the gas pressure is 10kpa, the two-stage short circuit of the electric arc furnace is 40min, the starting current of the electric arc furnace is 200A, and the non-noble metal manganese-cerium alloy is obtained by collecting the original ash after the anode graphite plate is consumed. In the above preparation process, the manganese dioxide and the cerium oxide are uniformly embedded into the five-membered ring carbon cage structure unique to graphite, which increases the contact area of the manganese-cerium alloy molecules in the external reaction process and also enhances the molecular structure, and the manganese-cerium alloy prepared by the method has better formaldehyde catalytic activation capacity and stability compared with other methods.
[0047] The above alloy is placed in a quartz tube, and dry air with an initial concentration of 1mg / m 3 of formaldehyde is introduced, the gas flow is 1L / min, the tail gas is sampled for 4min, the residual formaldehyde concentration in the sample is tested by ultraviolet spectrophotometry, phenyl reagent is selected as the absorption liquid, and the formaldehyde conversion rate is calculated (based on the amount of formaldehyde absorbed by the empty tube); the formaldehyde removal conversion rate can reach more than 95%.
[0048] Specifically, the effective mass fraction of the non-noble metal catalyst in the non-noble metal catalyst slurry in step S1 is 10-30%, and the rest is water. The effective mass fraction of the catalyst is ≥10%, which can exhibit excellent catalytic performance. When the effective mass fraction of the catalyst is too large, the flowability of the slurry will be reduced, which will affect the subsequent coating. Considering the flowability and cost of the slurry, the effective mass fraction of the catalyst should not be ≥30%.
[0049] Specifically, the specific parameters of the binding aid in step S2 are as follows:
[0050] The non-noble metal catalyst slurry contains 0.05-0.1% of polyacrylamide solution, wherein the relative molecular weight of the polyacrylamide is 3 million, and the effective mass concentration of the polyacrylamide is ≥90%; 0.1-0.3% of cetyltrimethylammonium bromide powder; and 0.1-1.0% of polyether carboxylic acid solution, wherein the effective mass concentration of the polyether carboxylic acid solution is ≥70%.
[0051] The three different adhesion aids are mixed and configured according to the above-mentioned ratio to have more optimal hydrophilic / lipophilic amphoteric properties, and the adhesion aid in the above-mentioned ratio does not affect the performance of the catalyst; in addition, too much adhesion aid will cover the surface of the catalyst, reducing the performance of the catalyst; too little adhesion aid will result in poor adhesion.
[0052] Preferably, the porous material is cordierite honeycomb ceramic, and the pore density is 200-600 mesh, and examples can be 200, 300, 400, 500, 600 mesh. Cordierite honeycomb ceramic has the advantages of regular pore structure, good thermal stability, low price, and convenient processing and molding; the commonly used size is 150mm*150mm*50mm.
[0053] Preferably, the cordierite honeycomb ceramic is pretreated before step S3, and is immersed in water for 0.5-1h to activate the surface hydroxyl group, which helps the non-metallic slurry mixing system to be uniformly coated on the surface.
[0054] Specifically, the specific operation of coating in step S3 is: the porous material is sleeved into one end of the rubber tube, the other end is connected to a negative pressure device, the mixed slurry is poured onto the porous material, the negative pressure pressure is controlled to be 60-80kpa, and the extraction time is 5-15s; the mass ratio of the mixed slurry to the porous material is 1-2:10, and examples can be 1:10, 1.1:10, 1.2:10, 1.3:10, 1.4:10, 1.5:10, 1.6:10, 1.7:10, 1.8:10, 1.9:10, 2:10. The purpose of this step is to make the mixed slurry flow up and down in the pore channel of the porous material, and then form a catalyst coating on the pore channel wall of the porous material. This parameter is conducive to forming a uniformly coated porous material module, and the coating thickness is moderate, which can ensure good formaldehyde removal effect and save cost. Too much mixed slurry will result in too thick coating and waste; too little mixed slurry will result in insufficient formaldehyde removal catalyst loading and affect the formaldehyde removal effect.
[0055] Specifically, the drying temperature in step S3 is 100-110℃, and the drying time is 2-3h. The purpose of this operation is to remove the moisture and volatile components of the porous material module to prevent the manganese-cerium alloy catalyst from being disturbed or releasing substances with peculiar smell when it plays a role in removing formaldehyde.
[0056] Specifically, the calcination temperature in step S3 is 500-650℃, and the calcination time is 2-3h. This step can activate the manganese-cerium alloy, improve its catalytic formaldehyde performance, and further pore the porous material to further increase its specific surface area and pore volume and increase its physical adsorption capacity for formaldehyde.
[0057] Preferably, during the calcination process, the porous material can be taken out, weighed, and its mass recorded at regular intervals, such as 0.1, 0.2, 0.3, 0.4, 0.5, and 1 hour. Calcination can be stopped when the mass no longer changes.
[0058] The present invention also discloses an air filter element, which is prepared by the above-described preparation method.
[0059] The air filter catalyst has good adhesion, low powder shedding rate, and high formaldehyde removal efficiency.
[0060] Specifically, the air filter has a dust shedding rate of ≤0.80%, and according to the testing method of GB / T18801-2022 "Air Purifiers", the formaldehyde clean air CADR value can reach up to 283.4, which has a good formaldehyde removal effect.
[0061] The following specific embodiments and comparative examples demonstrate the advantages of the air filter element prepared by the present invention over ordinary filter elements in terms of formaldehyde removal effect and powder removal rate, as well as the further optimization of some related parameters; the specific embodiments are used to illustrate the principle of the advantages of the present invention, and are not intended to limit the scope of the present invention.
[0062] Example 1
[0063] (1) Preparation of non-precious metal slurry: Mix 30g of non-precious metal manganese-cerium alloy with 120g of water, wherein the mass ratio of manganese dioxide, cerium trioxide and graphite powder in the manganese-cerium alloy is 2:1:30, and prepare a non-precious metal slurry with a non-precious metal mass concentration of 20%.
[0064] (2) Adding adhesive additives: Add 0.075g of polyacrylamide solution with a relative molecular weight of 3 million and an effective mass concentration of ≥90% to the above slurry in sequence, i.e., 0.05% of the slurry mass of polyacrylamide solution; 0.30g of cetyltrimethylammonium bromide, i.e., 0.2% of the slurry mass of cetyltrimethylammonium bromide; and 0.75g of polyether carboxylic acid solution, i.e., 0.5% of the slurry mass of polyether carboxylic acid solution; mix and disperse evenly, and divide it into 4 equal parts.
[0065] (3) Cordierite honeycomb ceramic pretreatment: Weigh 4 pieces of 400-mesh cordierite honeycomb ceramic with the same pore density to obtain a total weight of m1 (2082.34g). The 4 weighed pieces of cordierite honeycomb ceramic were completely immersed in water for 0.8h to wet the surface and activate the hydroxyl groups on the surface, which helps the non-metallic slurry mixing system to be uniformly coated on the surface.
[0066] (4) Coating non-precious metals on cordierite honeycomb ceramics: Insert one side of four pretreated cordierite honeycomb ceramics into one end of a rubber tube, connect the rubber tube to a negative pressure device, pour the above-mentioned mixed slurry divided into four equal parts into the other side, control the negative pressure to 70 kPa, and extract for 8 seconds.
[0067] (5) Drying the cordierite honeycomb ceramic loaded with non-precious metals: Place the four cordierite honeycomb ceramics loaded with metals into a drying oven at 100℃ for 2.5h, take them out and put them into a muffle furnace at 550℃ for calcination. Weigh them every 30min until the total mass of the four pieces no longer changes after three consecutive measurements. Then take them out to obtain sample 1 with a total mass of m2 (2111.31g). Finally, the total loading of the catalyst is m3 (28.97g), where m3 = m2 - m1.
[0068] Example 2
[0069] (1) Preparation of non-precious metal slurry: Mix 45g of non-precious metal manganese-cerium alloy with 105g of water, wherein the mass ratio of manganese dioxide, cerium trioxide and graphite powder in the manganese-cerium alloy is 2:1:30, and prepare a non-precious metal slurry with a non-precious metal mass concentration of 30%.
[0070] (2) Adding adhesive additives: Add 0.15g of polyacrylamide solution with a relative molecular weight of 3 million and an effective mass concentration of ≥90% to the above slurry in sequence, i.e., 0.1% of the slurry mass of polyacrylamide solution; 0.45g of cetyltrimethylammonium bromide, i.e., 0.3% of the slurry mass of cetyltrimethylammonium bromide; and 0.15g of polyether carboxylic acid solution, i.e., 0.1% of the slurry mass of polyether carboxylic acid solution; mix and disperse evenly, and divide it into 4 equal parts.
[0071] (3) Cordierite honeycomb ceramic pretreatment: Weigh 4 pieces of 600-mesh cordierite honeycomb ceramic with the same pore density to obtain a total weight of m4 (2146.37g). The 4 weighed pieces of cordierite honeycomb ceramic were completely immersed in water for 0.8h to wet the surface and activate the hydroxyl groups on the surface, which helps the non-metallic slurry mixing system to be uniformly coated on the surface.
[0072] (4) Coating non-precious metals on cordierite honeycomb ceramics: Insert one side of each of the four pretreated cordierite honeycomb ceramics into one end of the tubing, connect the tubing to the negative pressure device, pour the above-mentioned mixed slurry divided into four equal parts onto the other side, control the negative pressure to 80 kPa, and extract for 5 seconds.
[0073] (5) Drying the cordierite honeycomb ceramic loaded with non-precious metals: Place the four cordierite honeycomb ceramics loaded with the coating into a drying oven at 100℃ for 2 hours, take them out and place them in a muffle furnace at 650℃ for calcination. Weigh them every 30 minutes until the total mass of the four pieces no longer changes after three consecutive measurements. Then take them out to obtain sample 2, with a total mass of m5 (2188.21g). Finally, the total loading of the catalyst is m6 (41.84g), where m6 = m5 - m4.
[0074] Example 3
[0075] (1) Preparation of non-precious metal slurry: Mix 15g of non-precious metal manganese-cerium alloy with 135g of water, wherein the mass ratio of manganese dioxide, cerium trioxide and graphite powder in the manganese-cerium alloy is 2:1:30, and prepare a non-precious metal slurry with a non-precious metal mass concentration of 10%.
[0076] (2) Adding adhesive additives: Add 0.075g of polyacrylamide solution with a relative molecular weight of 3 million and an effective mass concentration of ≥90% to the above slurry in sequence, i.e., 0.05% of the slurry mass of polyacrylamide solution; 0.15g of cetyltrimethylammonium bromide, i.e., 0.1% of the slurry mass of cetyltrimethylammonium bromide; and 1.5g of polyether carboxylic acid solution, i.e., 1% of the slurry mass of polyether carboxylic acid solution; mix and disperse evenly, and divide it into 4 equal parts.
[0077] (3) Cordierite honeycomb ceramic pretreatment: Weigh 4 pieces of 200-mesh cordierite honeycomb ceramic with the same pore density to obtain a total weight of m7 (2041.87g). The 4 weighed pieces of cordierite honeycomb ceramic were completely immersed in water for 0.8h to wet the surface and activate the hydroxyl groups on the surface, which helps the non-metallic slurry mixing system to be uniformly coated on the surface.
[0078] (4) Coating non-precious metals on cordierite honeycomb ceramics: Insert one side of four pretreated cordierite honeycomb ceramics into one end of a rubber tube, connect the rubber tube to a negative pressure device, pour the above-mentioned mixed slurry divided into four equal parts into the other side, control the negative pressure to 60 kPa, and extract for 12 seconds.
[0079] (5) Drying the cordierite honeycomb ceramic loaded with non-precious metals: Place the four cordierite honeycomb ceramics loaded with metals into a drying oven at 110℃ for 2.5h, take them out and put them into a muffle furnace at 500℃ for calcination. Weigh them every 30min until the total mass of the four pieces no longer changes after three consecutive measurements. Then take them out to obtain sample 3, with a total mass of m8 (2055.61g). Finally, the total loading of the catalyst is m9 (13.74g), where m9 = m8 - m7.
[0080] Comparative Example 1
[0081] Compared with Example 1, Comparative Example 1 did not have the step of "adding adhesive additive", but the other steps were completely the same, resulting in Sample 4.
[0082] Comparative Example 2
[0083] Compared with Example 1, Comparative Example 2 did not have the final step of "calcining in a muffle furnace at 550°C until constant weight". The remaining steps were completely the same, and Sample 5 was obtained.
[0084] Comparative Example 3
[0085] Compared with Example 1, the operation steps of Comparative Example 3 are completely identical except that step 4 is "to pour one side of each of the four pretreated cordierite honeycomb ceramic pieces into the above-mentioned mixed slurry which is divided into four equal parts". The remaining steps are completely identical to obtain Sample 6.
[0086] The catalyst coating adhesion of the above samples was tested by purging with compressed air. The samples were purged with compressed air with an 8mm air pressure tube and an air pressure of 0.6MPa for 15 minutes and then weighed to calculate the powder loss rate.
[0087] The samples were then placed into a specific test frame (e.g., 302mm (length) * 302mm (width) * 50mm (height)). Figure 2 As shown in the diagram, the assembled state is as follows: Figure 3 As shown, the frame was placed inside the test air purifier. According to GB / T18801-2022 "Air Purifiers" test method, the air purifier was placed in a 30m... 3 In the experimental chamber, the formaldehyde clean air delivery rate (CADR) was measured using an air sampler and an ultraviolet spectrophotometer. The test results are shown in Table 2 below:
[0088] Table 2. Powder shedding rate and formaldehyde clean air delivery rate (CADR) of the samples.
[0089]
[0090] Based on the test results of samples 1, 2, and 3 above, the air filter element provided by this invention has a dust shedding rate of ≤0.80% and a formaldehyde clean air CADR value of 270m³. 3 The dust shedding rate was above 1 / h, with sample 1 in the examples exhibiting the lowest dust shedding rate and the highest formaldehyde clean air CADR value. Furthermore, the test results of samples 4, 5, and 6 indicate that the absence of any one of the following steps—lack of binder, lack of muffle furnace calcination, or lack of negative pressure extraction—affects the dust shedding rate and formaldehyde clean air CADR value of the air filter, with the lack of binder having the greatest impact on the dust shedding rate.
[0091] 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 changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for producing an air filter element for purifying formaldehyde, characterized by, The preparation method comprises the following specific steps: S1: weighing or measuring the non-noble metal catalyst and water, and mixing to prepare a non-noble metal catalyst slurry; S2: adding a binding aid to the non-noble metal catalyst slurry and mixing uniformly to obtain a mixed slurry; S3: coating the mixed slurry in a porous material which has been previously treated by water immersion, and drying and calcining to obtain a finished air filter element; The binding aid contains polyacrylamide, cetyltrimethylammonium bromide and polyether carboxylic acid.
2. The method of claim 1, wherein: The non-noble metal catalyst is a manganese-cerium alloy.
3. The method of claim 1, wherein: In step S1, the effective mass concentration of the non-noble metal catalyst in the non-noble metal catalyst slurry is 10-30%, and the rest is water.
4. The preparation method according to claim 1, characterized in that: In step S2, the specific parameters of the binding aid are as follows: 0.05-0.1% of a polyacrylamide solution by mass of the non-noble metal catalyst slurry, wherein the relative molecular weight of the polyacrylamide is 3 million, and the effective mass concentration of the polyacrylamide is ≥90%; 0.1-0.3% of cetyltrimethylammonium bromide powder by mass of the non-noble metal catalyst slurry; 0.1-1.0% of a polyether carboxylic acid solution by mass of the non-noble metal catalyst slurry, wherein the effective mass concentration of the polyether carboxylic acid is ≥70%.
5. The method of claim 1, wherein: The porous material is cordierite honeycomb ceramic, and the pore density is 200-600 mesh.
6. The preparation method according to claim 1, characterized in that: In step S3, the specific operation of coating is as follows: the porous material is sleeved into one end of a rubber tube, and the other end is connected to a negative pressure device, the negative pressure pressure is controlled to be 60-80 kpa, and suction is performed for 5-15 s; wherein the mass ratio of the mixed slurry to the porous material is 1-2:
10.
7. The method of claim 1, wherein: In step S3, the drying temperature is 100-110°C, and the drying time is 2-3 h.
8. The method of claim 1, wherein: In step S3, the calcining temperature is 500-650°C, and the calcining time is 2-3 h.
9. An air filter cartridge, characterized by: The air filter element is prepared by the preparation method according to any one of claims 1-8.
10. The air filter cartridge of claim 9 wherein: The powder drop rate of the air filter element is ≤0.80%.