A filter material, its preparation method and use

Abstract

The application provides a filter material which is composed of a filter layer and an adsorption layer which are tightly combined together; the raw material of the filter layer comprises the following components in parts by weight based on the absolute dry weight: 60-80 parts of glass fiber with a diameter of 200-300 nm, 15-35 parts of nanocellulose and 1-5 parts of water repellent agent; the water repellent agent is a cationic fluororesin; the raw material of the adsorption layer comprises the following components in parts by weight based on the absolute dry weight: 20-40 parts of PET fiber, 0-15 parts of PP / PET double melting point fiber, 30-55 parts of adsorption medium and 5-10 parts of water-soluble PVA fiber; the adsorption medium is selected from at least one of activated carbon fiber and activated carbon particles. The application also provides a preparation method of the filter material and application thereof. The filter material has a thin thickness, high adsorption efficiency and appropriate strength.

Description

Technical Field

[0001] This invention belongs to the field of papermaking and filter materials, specifically relating to a new filter material, its preparation method, and its application. Background Technology

[0002] For fuel cells, clean air free of particulate matter and harmful gases such as sulfur dioxide, ammonia, and nitrogen oxides plays a positive role in the fuel cell reaction. Therefore, the cathode (also known as the negative electrode) of a fuel cell has certain requirements for the incoming air; the air must pass through a filter element before flowing into the fuel cell cathode.

[0003] In existing technologies, fuel cell cathode air filters are mostly formed by folding carbon-reinforced nonwoven fabric. The surface filter layer of this type of filter is mostly made of melt-blown material, mainly used to filter particles; the middle filter layer is an activated carbon layer, used to adsorb and remove harmful gases such as sulfur dioxide, ammonia, and nitrogen oxides.

[0004] The activated carbon used in the aforementioned activated carbon layer is mostly coarse activated carbon of 30-120 mesh. As the particle size of the activated carbon increases, the resistance of the filter material increases, resulting in a higher requirement for activated carbon per unit area of ​​filter media. Therefore, this type of filter media is relatively thick. In actual processing, on the one hand, a specially matched pleating machine is needed for processing; on the other hand, due to the thickness of the material, the number of pleats per unit area of ​​the limited filter is small, resulting not only in a smaller effective filtration area but also in a higher overall resistance of the filter element after processing.

[0005] US Patent 10046271B2 discloses a filter material that bonds a filter layer and an adsorption layer together. The filter layer is formed by folding filter media, and the adsorption layer includes a metal honeycomb structure as a framework and a special activated carbon adsorbent containing manganese-based metal oxides bonded to it with an adhesive. This type of filter has the following drawbacks: First, the adsorbent content is limited by the size of the honeycomb pores; second, a large amount of adhesive can easily clog the activated carbon pores, reducing adsorption performance; third, this type of filter material requires complex processes to manufacture into a cylindrical filter element suitable for fuel cell cathode air filters.

[0006] Chinese patent application CN114288760A discloses a fuel cell cathode air filter adsorption material. This filter material is obtained by roll-coating a reinforcing liquid onto both sides of a base paper substrate; the reinforcing liquid contains an alkali modifier, a binder, an activated carbon adsorbent, and modified graphene prepared through a special process. However, this filter material not only has a complex manufacturing process, but also the reinforcing liquid still contains a significant amount of binder, which cannot avoid the problem of the binder clogging the pores of the activated carbon fibers, thus affecting the gas adsorption effect. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a novel filter material, its preparation method, and its applications. The filter material of this invention has the advantages of simple structure and good adsorption and filtration performance.

[0008] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0009] A filter media consisting of a tightly bonded filter layer and an adsorption layer;

[0010] Based on absolute dry weight, the raw material of the filter layer comprises the following components in parts by weight:

[0011] The composition includes 60-80 parts of glass fiber with a diameter of 200nm-300nm, 15-35 parts of nanocellulose, and 1-5 parts of water-resistant agent; the water-resistant agent is a cationic fluororesin.

[0012] Based on absolute dry weight, the raw material of the adsorption layer comprises the following components in parts by weight:

[0013] The composition includes 20-40 parts PET fiber, 0-15 parts PP / PET dual-melting-point fiber, 30-55 parts adsorption medium, and 5-10 parts water-soluble PVA fiber; the adsorption medium is selected from at least one of activated carbon fiber and activated carbon particles.

[0014] Preferably, the thickness of the filter material is 0.5-0.8 mm, and the thickness of the adsorption layer is 0.3-0.5 mm.

[0015] Preferably, the paper basis weight of the filter layer is 1-15 g / m³. 2 More preferably 5g / m 2 .

[0016] The raw material of the filter layer includes:

[0017] Preferably, the beating degree of the glass fiber is 54-79°SR.

[0018] Preferably, the nanocellulose has a diameter of 10-500 nm and a length of 500-2000 μm.

[0019] Preferably, the water-repellent agent is a C6 waterproofing agent or a C8 waterproofing agent.

[0020] More preferably, the water-repellent agent is a C6 waterproofing agent.

[0021] Preferably, the paper basis weight of the adsorption layer is 70-150 g / m³. 2 More preferably 120g / m 2 .

[0022] The raw material of the adsorption layer:

[0023] Preferably, the adsorption medium is a mixture of activated carbon fiber and activated carbon particles; based on the total weight of the adsorption medium as 100%, the activated carbon fiber accounts for 70%-90%, and the remainder is activated carbon particles.

[0024] More preferably, the adsorption medium is a mixture of activated carbon fiber and activated carbon particles; based on the total weight of the adsorption medium as 100%, the activated carbon fiber accounts for 80%-90%, and the remainder is activated carbon particles.

[0025] Preferably, the activated carbon fiber has a BET specific surface area of ​​1300-2000 m². 2 / g.

[0026] Preferably, the activated carbon particles pass through a 200-325 mesh sieve and have an iodine value of 1100-1500.

[0027] Preferably, the diameter of the PET fiber is 2-7 μm, the diameter of the PP / PET dual-melting-point fiber is 10-15 μm, and the diameter of the water-soluble PVA fiber is 5-15 μm.

[0028] Another object of the present invention is to provide a method for preparing the above-mentioned filter material, including pulping and molding; the specific steps include:

[0029] I. Pulping

[0030] I-1. Preparation of Adsorption Layer Slurry

[0031] Add the specified weight proportions of PET fiber, PP / PET dual-melting-point fiber, adsorption medium and water-soluble PVA fiber to water, then add alkali, mix, and pulp to prepare a slurry with pH=12±1 and solid content of 5-8%.

[0032] I-2. Preparation of Filter Layer Slurry

[0033] The glass fiber, nanocellulose and water-resistant agent in the specified weight parts are added to water, mixed and pulped to obtain a filter layer slurry with a solid content of 1-3%.

[0034] II. Molding

[0035] The adsorption layer slurry is dehydrated on the forming wire of the paper machine to form an adsorption layer paper blank. The filter layer slurry is then uniformly coated onto the adsorption layer paper blank and dehydrated to obtain a double-layer wet blank.

[0036] III. Drying and Curing

[0037] The double-layer wet blank obtained in step II is dried at 80±5℃ until the moisture content is ≤3%, and then cured at 120-160℃ for 5-10 minutes.

[0038] Preferably, in step I-1, the alkali is selected from one or more of sodium hydroxide, potassium hydroxide, and sodium bicarbonate.

[0039] A third objective of this invention is to provide the application of the above-described filter material or the filter material prepared by the above-described preparation method in air filtration; particularly in the application of fuel cell cathode air filtration.

[0040] Furthermore, another objective of this invention is to provide an air filtration device, comprising the filter material described in this invention or the filter material prepared by the preparation method described in this invention.

[0041] The present invention also provides the application of the above-described air filtration device in filtering air flowing into a fuel cell.

[0042] The filter material provided by this invention has a simple structure and manufacturing process, yet boasts a high adsorption rate. Its thin thickness facilitates folding and fabrication into a filter element for an air filter used in fuel cells. Compared to existing carbon-filled filter materials with a thickness exceeding 1.2 mm, the filter material of this invention can achieve approximately twice the number of folds. Therefore, air filtration devices equipped with the filter material described in this invention exhibit higher filtration efficiency.

[0043] The filter material provided by this invention has an adsorption medium in the adsorption layer selected from one or two of activated carbon fibers and activated carbon particles, preferably a mixture of activated carbon fibers and activated carbon particles. This invention achieves a balance between filtration and gas adsorption functions and flow resistance through a preferred mass ratio of activated carbon fibers to activated carbon particles. Specifically, based on the total weight of the adsorption medium as 100%, the activated carbon fibers account for 70%-90%, preferably 80%-90%, with the remainder being activated carbon particles. Attached Figure Description

[0044] The present invention will be further described below with reference to the accompanying drawings.

[0045] Figure 1 This is a cross-sectional view of the filter material of Example 1 under a scanning electron microscope (magnification 500X).

[0046] Figure 2 This is an electron microscope image of the adsorption layer of the filter material in Example 1.

[0047] Figure 3 This is an electron microscope micrograph of the filter layer of the filter material in Example 1.

[0048] The above Figures 1-3 In the diagram, 1 represents the adsorption layer, and 2 represents the filtration layer. Implementation

[0049] This invention provides a novel filter material with a simple structure and high filtration efficiency, consisting of a tightly bonded adsorption layer and a filter layer. The thickness of the double-layer filter material of this invention is 0.5-0.8 mm, wherein the thickness of the adsorption layer is 0.3-0.5 mm.

[0050] The adsorption layer has a fibrous paper structure, which serves as the framework for the filter layer and can also adsorb harmful gases that affect the electrochemical reaction of the fuel cell, such as sulfur dioxide, hydrogen sulfide, ammonia, and nitrogen oxides.

[0051] Based on absolute dry weight, the raw material of the adsorption layer comprises the following components in parts by weight:

[0052] The composition includes 20-40 parts by weight of PET fiber, 0-15 parts by weight of PP / PET dual-melting-point fiber, 30-55 parts by weight of adsorption medium, and 5-10 parts by weight of water-soluble PVA fiber. The adsorption medium is selected from at least one of activated carbon fiber and activated carbon granules, preferably two. More preferably, the adsorption medium is a mixture of activated carbon fiber and activated carbon granules, wherein, based on a total weight of 100 parts of the adsorption medium, the activated carbon fiber comprises 70-90 parts by weight, more preferably 80-90 parts, with the remainder being activated carbon granules.

[0053] The quantitative concentration of the adsorption layer is 70-150 g / m³. 2 Preferably 120 g / m 2 .

[0054] The filter layer is directly and tightly attached to one surface of the adsorption layer, and has a denser fibrous network structure than the adsorption layer. The filter layer is capable of filtering particulate matter.

[0055] Based on absolute dry weight, the raw material of the filter layer comprises the following components in parts by weight:

[0056] 60-80 parts by weight of glass fiber with a diameter of 200nm-300nm, 15-35 parts by weight of nanocellulose, and 1-5 parts by weight of water-resistant agent.

[0057] The water-repellent agent is a cationic fluoropolymer, such as a C6 waterproofing agent and / or a C8 waterproofing agent. For environmental friendliness, a C6 waterproofing agent is preferred.

[0058] The quantitative amount of the filter layer is 1-15 g / m³. 2 Preferably 12 g / m 2 .

[0059] The present invention will be described below with reference to specific embodiments. Those skilled in the art will understand that these embodiments are for illustrative purposes only and do not limit the scope of the invention in any way.

[0060] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all raw materials and reagents used in the following examples are commercially available products. The purchase details of some raw materials and reagents are as follows:

[0061] PET fiber: 0.7D denier, 6mm length, manufactured by Teijin Ltd., Japan;

[0062] PP / PET dual melting point fiber: denier 1.5D, length 6mm, manufactured by Kumatsu Corporation, Japan;

[0063] Activated carbon fiber: Product model BET1500, manufactured by Calgon Ltd.

[0064] Activated carbon granules: KBEVsuper coconut shell activated carbon, manufactured by Cabot Corporation;

[0065] Water-soluble PVA fiber: Product model VPB041, water solubility temperature 80°C, manufactured by Kuraray Co., Ltd., Japan;

[0066] Glass fiber: Product model 475-59, freeness 59°SR, produced by Shenyang Dongxiang Company;

[0067] Nanocellulose: Product model CNFS, manufactured by Northern Century Cellulose Materials Co., Ltd.

[0068] Water-repellent agent: C6 cationic waterproof and oil-repellent agent, product model TG-5574, manufactured by Daikin Industries, Japan.

[0069] Paper machine: Multi-layer composite pilot paper machine, manufactured by Guangzhou Huachuang Chemical Materials Technology Development Co., Ltd.

[0070] Example 1: A filter material

[0071] The filter media in this embodiment consists of a tightly bonded adsorption layer and a filtration layer. The compositions of the adsorption layer and the filtration layer, based on oven-dry weight, are as follows:

[0072] (1) Adsorption layer: 25 parts by weight of PET fiber, 5 parts by weight of PP / PET dual melting point fiber, 50 parts by weight of activated carbon fiber, 10 parts by weight of activated carbon granules, and 10 parts by weight of water-soluble PVA fiber; where 1 part by weight = 1 kg; the papermaking quantity is 120 g / m 2 .

[0073] (2) Filter layer: 70 parts by weight of glass fiber, 25 parts by weight of nanocellulose, and 5 parts by weight of water-resistant agent; where 1 part by weight = 1 kg. The papermaking quantity is 15 g / m³. 2 .

[0074] The filter material in this embodiment is prepared by the following method:

[0075] I. Pulping

[0076] I-1. Preparation of Adsorption Layer Slurry

[0077] The five materials of the adsorption layer were added to a pulper, along with water and potassium hydroxide, to achieve a potassium hydroxide concentration of 5% and a solid content of 7%. The pulper was started and pulped for 30 minutes to obtain the adsorption layer slurry.

[0078] I-2. Preparation of Filter Layer Slurry

[0079] The three materials of the filter layer were added to a pulper and stirred, and water was added to make the solid content 2%. The pulper was started and pulped for 30 minutes to obtain the filter layer slurry.

[0080] II. Molding

[0081] The adsorption layer slurry is transferred to the pulping tank of the paper machine, and the filter layer slurry is transferred to the sheet coating preparation tank of the paper machine. The paper machine is started, and the adsorption layer slurry is pumped to the forming wire and vacuum-dehydrated to form an adsorption layer paper blank. Then, the filter layer slurry is evenly coated onto the adsorption layer paper blank using a coating machine, and vacuum-dehydrated to obtain a double-layer wet blank.

[0082] III. Drying and Curing

[0083] The double-layer wet blank obtained in step II is dried at 80℃±5℃ until the moisture content is ≤3%, and then cured at 120-160℃ for 5-10 minutes.

[0084] The cross-sectional image of the filter material prepared in this embodiment under a scanning electron microscope (magnification 500X) is shown below. Figure 1 The magnified micrograph of the adsorption layer is shown below. Figure 2 See the magnified micrograph of the filter layer. Figure 3 .

[0085] Example 2: A filter material

[0086] The filter media in this embodiment consists of a tightly bonded adsorption layer and a filtration layer. The adsorption layer and the filtration layer are composed of the following:

[0087] (1) Adsorption layer: 15 parts by weight of PET fiber, 15 parts by weight of PP / PET dual melting point fiber, 50 parts by weight of activated carbon fiber, 10 parts by weight of activated carbon granules, and 10 parts by weight of water-soluble PVA fiber; where 1 part by weight = 1 kg; the papermaking quantity is 120 g / m 2 .

[0088] (2) Filter layer: 70 parts by weight of glass fiber, 25 parts by weight of nanocellulose, and 5 parts by weight of water-resistant agent; where 1 part by weight = 1 kg. The papermaking quantity is 15 g / m³. 2 .

[0089] The filter material in this embodiment was prepared using the same methods and steps as in Example 1.

[0090] Example 3: A filter material

[0091] The filter media in this embodiment consists of a tightly bonded adsorption layer and a filtration layer. The adsorption layer and the filtration layer are composed of the following:

[0092] (1) Adsorption layer: 25 parts by weight of PET fiber, 15 parts by weight of PP / PET dual melting point fiber, 40 parts by weight of activated carbon fiber, 10 parts by weight of activated carbon granules, and 10 parts by weight of water-soluble PVA fiber; where 1 part by weight = 1 kg; the papermaking quantity is 120 g / m 2 .

[0093] (2) Filter layer: 70 parts by weight of glass fiber, 25 parts by weight of nanocellulose, and 5 parts by weight of water-resistant agent; where 1 part by weight = 1 kg. The papermaking quantity is 15 g / m³. 2 .

[0094] The filter material in this embodiment was prepared using the same methods and steps as in Example 1.

[0095] Example 4: A filter material

[0096] The filter media in this embodiment consists of a tightly bonded adsorption layer and a filtration layer. The adsorption layer and the filtration layer are composed of the following:

[0097] (1) Adsorption layer: 45 parts by weight of PET fiber, 15 parts by weight of PP / PET dual melting point fiber, 30 parts by weight of activated carbon fiber, 5 parts by weight of activated carbon granules, and 5 parts by weight of water-soluble PVA fiber; where 1 part by weight = 1 kg; the papermaking quantity is 120 g / m 2 .

[0098] (2) Filter layer: 70 parts by weight of glass fiber, 25 parts by weight of nanocellulose, and 5 parts by weight of water-resistant agent; where 1 part by weight = 1 kg. The papermaking quantity is 15 g / m³. 2 .

[0099] The filter material in this embodiment was prepared using the same methods and steps as in Example 1. Example

[0100] The filter media in this embodiment consists of a tightly bonded adsorption layer and a filtration layer. The adsorption layer and the filtration layer are composed of the following:

[0101] (1) Adsorption layer: 25 parts by weight of PET fiber, 5 parts by weight of PP / PET dual melting point fiber, 50 parts by weight of activated carbon fiber, 10 parts by weight of activated carbon granules, and 10 parts by weight of water-soluble PVA fiber; where 1 part by weight = 1 kg; the papermaking quantity is 120 g / m 2 .

[0102] (2) Filter layer: 60 parts by weight of glass fiber, 35 parts by weight of nanocellulose, and 5 parts by weight of water-resistant agent; where 1 part by weight = 1 kg. The papermaking quantity is 15 g / m³. 2 .

[0103] The filter material in this embodiment was prepared using the same methods and steps as in Example 1.

[0104] Comparative Example 1: A filter material

[0105] The filter media in this comparative example consists of a tightly bonded adsorption layer and a filtration layer. The compositions of the adsorption layer and the filtration layer are as follows:

[0106] (1) Adsorption layer: 15 parts by weight of PET fiber, 5 parts by weight of PP / PET dual melting point fiber, 70 parts by weight of activated carbon fiber, and 10 parts by weight of activated carbon granules; where 1 part by weight = 1 kg; the papermaking quantity is 120 g / m 2 .

[0107] (2) Filter layer: 70 parts by weight of glass fiber, 25 parts by weight of nanocellulose, and 5 parts by weight of water-resistant agent; where 1 part by weight = 1 kg. The papermaking quantity is 15 g / m³. 2 .

[0108] The filter material of this comparative example was prepared using a method and steps similar to those in Example 1. In terms of raw material composition, the adsorption layer slurry of this comparative example did not contain water-soluble PVA fibers and had a low PET fiber content.

[0109] Comparative Example 2: A filter material

[0110] The filter media in this comparative example consists of a tightly bonded adsorption layer and a filtration layer. The compositions of the adsorption layer and the filtration layer are as follows:

[0111] (1) Adsorption layer: 25 parts by weight of PET fiber, 5 parts by weight of PP / PET dual melting point fiber, 50 parts by weight of activated carbon fiber, 10 parts by weight of activated carbon granules, and 10 parts by weight of water-soluble PVA fiber; where 1 part by weight = 1 kg; the papermaking quantity is 130 g / m 2 .

[0112] (2) Filter layer: 90 parts by weight of glass fiber, 5 parts by weight of nanocellulose, and 5 parts by weight of water-resistant agent; where 1 part by weight = 1 kg. The papermaking quantity is 5 g / m³. 2 .

[0113] This comparative example was prepared using the same methods and steps as in Example 1. In terms of raw material composition, the filter layer of this comparative example has a higher content of glass fiber and a lower content of nanocellulose.

[0114] Test Example: Performance Determination of Filter Media in Examples and Comparative Examples

[0115] The performance of the filter media prepared in the above embodiments and comparative examples was measured using the following methods or equipment:

[0116] Quantitative standard: GB / T451.2;

[0117] Thickness: GB / T451.3;

[0118] Breathability: GB / T5453;

[0119] Bursting strength: GB / T454;

[0120] Stiffness: GB / T22364;

[0121] 0.26-micron filtration efficiency: TSI8130 tester, at 32 L / min and a test area of ​​100 cm². 2 Test under the conditions;

[0122] SO2 gas adsorption efficiency: TSI8130 tester, using 100ppm standard 99.9% SO2 gas in an area of ​​20cm² 2 Tested under a surface flow velocity of 2.5 cm / s.

[0123] The measurement results are shown in Table 1.

[0124] Table 1. Performance test results of filter media in each embodiment and comparative example.

[0125]

[0126] As can be seen from the results in Table 1, according to the method of the present invention, it is possible to obtain a thinner filter material for air filters that has high adsorption efficiency and the strength required for practical use.

Claims

1. A filter material for filtering cathode air in a fuel cell, comprising a filter layer and an adsorption layer tightly bonded together; the filter material has a thickness of 0.5-0.8 mm, wherein the adsorption layer has a thickness of 0.3-0.5 mm; The raw material of the filter layer, based on its oven-dry weight, consists of the following components in parts by weight: The composition includes 60-80 parts of glass fiber with a diameter of 200nm-300nm, 15-35 parts of nanocellulose, and 1-5 parts of water-resistant agent; the water-resistant agent is a cationic fluororesin. The glass fiber has a beating degree of 54-79°SR; Based on absolute dry weight, the raw material of the adsorption layer consists of the following components in parts by weight: The composition includes 20-40 parts PET fiber, 0-15 parts PP / PET dual-melting-point fiber, 30-55 parts adsorption medium, and 5-10 parts water-soluble PVA fiber; the adsorption medium is selected from at least one of activated carbon fiber and activated carbon particles. The filter material is prepared by a method comprising the following steps: I. Pulping I-1. Preparation of Adsorption Layer Slurry Add the specified weight proportions of PET fiber, PP / PET dual-melting-point fiber, adsorption medium and water-soluble PVA fiber to water, then add alkali, mix, and pulp to prepare a slurry with pH=12±1 and solid content of 5-8%. I-2. Preparation of Filter Layer Slurry The glass fiber, nanocellulose and water-resistant agent in the specified weight parts are added to water, mixed and pulped to obtain a filter layer slurry with a solid content of 1-3%. II. Molding The adsorption layer slurry is dehydrated on the forming wire of the paper machine to form an adsorption layer paper blank. The filter layer slurry is then uniformly coated onto the adsorption layer paper blank and dehydrated to obtain a double-layer wet blank. III. Drying and Curing The double-layer wet blank obtained in step II is dried at 80±5℃ until the moisture content is ≤3%, and then cured at 120-160℃ for 5-10 minutes.

2. The filter material according to claim 1, characterized in that, The paper basis weight of the filter layer is 1-15 g / m³. 2 .

3. The filter material according to claim 2, characterized in that, The paper basis weight of the filter layer is 5g / m³. 2 .

4. The filter material according to claim 1, characterized in that, In the raw material of the filter layer, the nanocellulose has a diameter of 10-500 nm and a length of 500-2000 μm.

5. The filter material according to claim 1, characterized in that, The water-resistant agent in the raw materials of the filter layer is either a C6 waterproofing agent or a C8 waterproofing agent.

6. The filter material according to claim 5, characterized in that, The water-resistant agent in the raw materials of the filter layer is C6 waterproofing agent.

7. The filter material according to claim 1, characterized in that, The paper basis weight of the adsorption layer is 70-150 g / m³. 2 .

8. The filter material according to claim 7, characterized in that, The paper basis weight of the adsorption layer is 120g / m³. 2 .

9. The filter material according to claim 1, characterized in that, In the raw materials of the adsorption layer, the adsorption medium is a mixture of activated carbon fiber and activated carbon particles; based on the total weight of the adsorption medium as 100%, the activated carbon fiber accounts for 70%-90%, and the remainder is activated carbon particles.

10. The filter material according to claim 9, characterized in that, The adsorption medium is a mixture of activated carbon fiber and activated carbon particles; based on the total weight of the adsorption medium as 100%, the activated carbon fiber accounts for 80%-90%, and the remainder is activated carbon particles.

11. The filter material according to claim 1, 9, or 10, characterized in that, The activated carbon fiber has a BET specific surface area of ​​1300-2000 m². 2 / g.

12. The filter material according to claim 1, 9, or 10, characterized in that, The activated carbon particles pass through a 200-325 mesh sieve and have an iodine value of 1100-1500.

13. The filter material according to claim 1, characterized in that, In the raw materials of the adsorption layer, the diameter of the PET fiber is 2-7 μm, the diameter of the PP / PET dual-melting-point fiber is 10-15 μm, and the diameter of the water-soluble PVA fiber is 5-15 μm.

14. A method for preparing the filter material according to any one of claims 1 to 13: comprising pulping and molding; The specific steps include: I. Pulping I-1. Preparation of Adsorption Layer Slurry Add the specified weight proportions of PET fiber, PP / PET dual-melting-point fiber, adsorption medium and water-soluble PVA fiber to water, then add alkali, mix, and pulp to prepare a slurry with pH=12±1 and solid content of 5-8%. I-2. Preparation of Filter Layer Slurry The glass fiber, nanocellulose and water-resistant agent in the specified weight parts are added to water, mixed and pulped to obtain a filter layer slurry with a solid content of 1-3%. II. Molding The adsorption layer slurry is dehydrated on the forming wire of the paper machine to form an adsorption layer paper blank. The filter layer slurry is then uniformly coated onto the adsorption layer paper blank and dehydrated to obtain a double-layer wet blank. III. Drying and Curing The double-layer wet blank obtained in step II is dried at 80±5℃ until the moisture content is ≤3%, and then cured at 120-160℃ for 5-10 minutes.

15. The preparation method according to claim 14, characterized in that, In step I-1, the alkali is selected from one or more of sodium hydroxide, potassium hydroxide, and sodium bicarbonate.

16. The use of the filter material according to any one of claims 1 to 13 or the filter material prepared by the preparation method according to claim 14 or 15 in air filtration.

17. The application of the filter material according to any one of claims 1 to 13 or the filter material prepared by the preparation method according to claim 14 or 15 in the cathode air filtration of a fuel cell.

18. An air filtration device comprising the filter material according to any one of claims 1 to 13 or the filter material prepared by the preparation method according to claim 14 or 15.

19. The air filtration device of claim 18 is used for filtering air flowing into a fuel cell.

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