Filter element and application thereof

Abstract

The invention belongs to the technical field of coal mine dust removal, and particularly relates to a filter element and application thereof. The filter element comprises a metal net, a diffusion adsorption layer, a deep filter layer and a deep purification layer which are stacked; the diffusion adsorption layer comprises one or more of glass fiber filter paper, an activated carbon fiber layer, electret melt-blown cloth and antistatic melt-blown cloth; the deep filter layer comprises one or more of high-efficiency air filter paper, a nanofiber membrane and superfine glass fiber filter paper; the deep purification layer comprises one or more of ultra-efficient air filtering filter paper, a graphene-based composite film, a metal organic framework and photocatalytic TiO2 coating ultra-efficient filter paper. The filter element has the beneficial effects that the filter elements can be matched with one another according to the characteristics of mine dust, progressive layer by layer to form an all-directional filter system from large particles to fine particles and from particles to harmful gas and microorganisms, harmful substances in coal mine air can be efficiently removed, and a clean and safe breathing environment is provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mine dust removal, and particularly relates to a filter element and its application. Background Art

[0002] With the vigorous development of the construction of intelligent mines, the degree of mechanization, automation, and intelligence in coal mining is continuously improving, and the dust hazard is becoming increasingly serious. Under the new mining conditions, the total dust concentration and respirable dust (<5μm) concentration in the fully mechanized mining face can reach 4000mg / m 3 and 1100mg / m 3 respectively, and the total dust concentration and respirable dust concentration in the heading face can reach 3000mg / m 3 and 2000mg / m 3 respectively. Calculated based on the proportion of fine and ultrafine particles being 40%-50%, the concentration of dust (<5μm) that can enter the deep part of the miner's respiratory tract, bronchioles, and alveoli in the mining and excavation faces can reach as high as 550mg / m 3 and 1000mg / m 3 respectively, far exceeding the requirement of the "Coal Mine Safety Regulations" that the average respirable dust is less than 2.5mg / m 3 . Given the diameter of fine-ultrafine particles, the particle number concentration of this part of the dust particles (particle number concentration: the number of particulate matter contained in unit volume of air) will be even higher. Although coal miners are already equipped with KN95 or powered air-purifying respirators, when conducting dust-proof experimental tests on KN95 masks or powered air-purifying filter respirators, NaCl non-oily particles or dioctyl phthalate oily particles are used, which have a large difference in nature from real coal and rock dust particulate matter and cannot truly reflect the effective protection of the protective equipment against coal and rock dust; even if coal miners are already equipped with KN95 or powered air-purifying respirators, a large amount of dust <2μm can still be detected in the lung lavage fluid of coal workers with coal worker's pneumoconiosis, indicating that the current protective equipment cannot effectively protect miners. Summary of the Invention

[0003] The present application provides a filter element and its application, aiming to improve the filtration efficiency of organic-inorganic composite particulate matter of respirable dust in coal mines.

[0004] The first aspect of the present application provides a filter element, which includes a metal mesh, a diffusion adsorption layer, a depth filtration layer, and a depth purification layer arranged in a stacked manner;

[0005] The diffusion adsorption layer includes one or more of glass fiber filter paper, activated carbon fiber layer, electret meltblown cloth, and antistatic meltblown cloth;

[0006] The depth filtration layer includes one or more of high-efficiency air filter paper, nanofiber membrane, and ultra-fine glass fiber filter paper;

[0007] The deep purification layer includes one or more of ultra-high efficiency air filter paper, graphene-based composite film, metal-organic framework, and photocatalytic TiO 2 coated ultra-high efficiency filter paper.

[0008] In some embodiments of the filter element according to the present application, the pore size of the metal mesh is 35 - 45 μm.

[0009] In some embodiments of the filter element according to the present application, the thickness of the diffusion adsorption layer is 0.3 - 10 mm; wherein the thickness of the glass fiber filter paper can be 1 - 3 mm, the thickness of the activated carbon fiber layer can be 0.5 - 2 mm, and the thickness of the electret meltblown cloth can be 0.3 - 1 mm.

[0010] In some embodiments of the filter element according to the present application, the thickness of the deep filtration layer is 0.1 - 3 mm; wherein the thickness of the high-efficiency air filter paper (HEPA) can be 0.5 - 2 mm, the thickness of the nanofiber membrane can be 0.1 - 0.5 mm, and the thickness of the ultra-fine glass fiber filter paper can be 0.3 - 1.5 mm.

[0011] In some embodiments of the filter element according to the present application, the thickness of the deep purification layer is 0.05 - 2 mm; wherein the thickness of the ultra-high efficiency air filter paper (ULPA) can be 0.5 - 1.5 mm, the thickness of the graphene-based composite film can be 0.05 - 0.3 mm, and the thickness of the metal-organic framework (MOFs) can be 0.1 - 0.5 mm.

[0012] The second aspect of the present application provides an application of the filter element described in the first aspect of the present application in a device for filtering coal mine dust.

[0013] The third aspect of the present application provides a coal mine dust filtering device, including the filter element described in the first aspect of the present application.

[0014] In some embodiments of the coal mine dust filtering device according to the present application, when the inorganic mineral content in the coal mine dust > 50%, the diffusion adsorption layer is a composite layer of electret meltblown cloth and glass fiber filter paper, the deep filtration layer is a nanofiber membrane layer, and the deep purification layer is a metal-organic framework layer.

[0015] In some embodiments of the coal mine dust filtering device according to the present application, when the organic matter content in the coal mine dust > 50%, the diffusion adsorption layer is a composite layer of activated carbon fiber layer and antistatic meltblown cloth, the deep filtration layer is a nanofiber membrane layer, and the deep purification layer is a photocatalytic TiO 2 coated ultra-high efficiency filter paper layer.

[0016] In some embodiments of the coal mine dust filtering device according to the present application, when the concentration of the coal mine dust is 1000 - 1500 mg / m3 When the inorganic mineral content in the coal mine dust is > 50%, the thickness of the diffusion adsorption layer is 3 - 5 mm, the thickness of the depth filtration layer is 1 - 2 mm, and the thickness of the depth purification layer is 0.5 - 1 mm.

[0017] According to some embodiments of the coal mine dust filtration device of the present application, when the concentration of the coal mine dust is 1000 - 1500 mg / m 3 When the organic matter content in the coal mine dust is > 50%, the thickness of the diffusion adsorption layer is 4 - 6 mm, the thickness of the depth filtration layer is 1.5 - 2.5 mm, and the thickness of the depth purification layer is 0.8 - 1.2 mm.

[0018] According to some embodiments of the coal mine dust filtration device of the present application, when the concentration of the coal mine dust > 1500 mg / m 3 and the inorganic mineral content in the coal mine dust is > 50%, the thickness of the diffusion adsorption layer is 5 - 8 mm, the thickness of the depth filtration layer is 2 - 3 mm, and the thickness of the depth purification layer is 1 - 2 mm.

[0019] According to some embodiments of the coal mine dust filtration device of the present application, when the concentration of the coal mine dust > 1500 mg / m 3 and the organic matter content in the coal mine dust is > 50%, the thickness of the diffusion adsorption layer is 6 - 10 mm, the thickness of the depth filtration layer is 2 - 3 mm, and the thickness of the depth purification layer is 1 - 1.5 mm.

[0020] According to some embodiments of the coal mine dust filtration device of the present application, when the particles constituting the coal mine dust contain oxygen-containing functional groups, plasma graft modification is performed on the diffusion adsorption layer to introduce carboxyl groups, and a composite coating of silica and polyethyleneimine is coated on the depth filtration layer.

[0021] According to some embodiments of the coal mine dust filtration device of the present application, when the particles constituting the coal mine dust contain iron elements, magnetic nano-composite is performed on the diffusion adsorption layer, and a composite coating of graphene and polydopamine is coated on the depth filtration layer.

[0022] The beneficial effects of the present application include: The four-layer structure of the metal mesh, diffusion adsorption layer, depth filtration layer, and depth purification layer contained in the filter element of the present application cooperate with each other according to the characteristics of mine dust and progress layer by layer, forming an all-round filtration system from large particles to fine particles, from particulate matter to harmful gases and microorganisms, which can efficiently remove harmful substances in the coal mine air and provide a clean and safe breathing environment for coal miners.

[0023] The filter element described in this application has strong adaptability and can be used not only for coal mine dust removal, but also in other industrial fields with high air purification requirements, such as chemical industry, electronics, pharmaceuticals, etc. Detailed implementation mode

[0024] The embodiments of the present invention will be described in detail below. The examples of the embodiments are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0025] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0026] The embodiment of this application provides a filter element, which includes a metal mesh, a diffusion adsorption layer, a depth filtration layer, and a depth purification layer arranged in a stacked manner;

[0027] The diffusion adsorption layer includes one or more of glass fiber filter paper, activated carbon fiber layer, electret meltblown cloth, and antistatic meltblown cloth;

[0028] The depth filtration layer includes one or more of high-efficiency air filtration filter paper, nanofiber membrane, and ultra-fine glass fiber filter paper;

[0029] The depth purification layer includes one or more of ultra-high-efficiency air filtration filter paper, graphene-based composite membrane, metal-organic framework, and photocatalytic TiO 2 Coated ultra-high-efficiency filter paper, etc.

[0030] The metal mesh of the filter element described in this application can be used as the first stage of filtration to preliminarily filter large-particle dust, and the diffusion adsorption layer can effectively block inhalable dust with a particle size less than 10 μm; the depth filtration layer can block particles with a particle size of 2-5 μm, and the depth purification layer can block particulate matter with a particle size < 2 μm. The filter element described in this application is designed with multiple filtration layers to efficiently filter coal mine dust underground.

[0031] In some embodiments of this application, the aperture of the metal mesh is 35-45 μm; for example, 35 μm, 40 μm, 42 μm, 45 μm, etc.

[0032] In some embodiments of the present application, the thickness of the diffusion adsorption layer is 0.3 - 10 mm; for example, 0.3 mm, 1 mm, 2.2 mm, 2.8 mm, 3.6 mm, 4.7 mm, 5.8 mm, 6.7 mm, 7.3 mm, 8.1 mm, 9.0 mm, 10 mm, etc.

[0033] In some embodiments of the present application, the thickness of the depth filtration layer is 0.1 - 3 mm; for example, 0.1 mm, 0.9 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2.1 mm, 3 mm, etc.

[0034] In some embodiments of the present application, the thickness of the depth purification layer is 0.05 - 2 mm; for example, 0.05 mm, 0.09 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.6 mm, 1.3 mm, 1.6 mm, 2 mm, etc.

[0035] The embodiments of the present application further provide an application of the filter element described in the first aspect of the present application in a device for filtering coal mine dust.

[0036] The embodiments of the present application further provide a coal mine dust filtering device, including the filter element described in the first aspect of the present application.

[0037] In some embodiments of the present application, when the inorganic mineral content in coal mine dust > 50%, the diffusion adsorption layer is a composite layer of electret meltblown cloth and glass fiber filter paper, the depth filtration layer is a nanofiber membrane layer, and the depth purification layer is a metal-organic framework layer.

[0038] In some embodiments of the present application, when the organic matter content in coal mine dust > 50%, the diffusion adsorption layer is a composite layer of activated carbon fiber layer and antistatic meltblown cloth, the depth filtration layer is a nanofiber membrane layer, and the depth purification layer is a photocatalytic TiO 2 coated ultra-high efficiency filter paper layer.

[0039] In some embodiments of the present application, when the concentration of coal mine dust is 1000 - 1500 mg / m 3 and the inorganic mineral content in coal mine dust > 50%, the thickness of the diffusion adsorption layer is 3 - 5 mm, for example, 3 mm, 3.5 mm, 4.3 mm, 4.7 mm, 5 mm, etc., the thickness of the depth filtration layer is 1 - 2 mm, for example, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, etc., and the thickness of the depth purification layer is 0.5 - 1 mm, for example, 0.5 mm, 0.8 mm, 0.9 mm, 1 mm, etc.

[0040] In some embodiments of the present application, when the concentration of coal mine dust is 1000 - 1500 mg / m 3When the organic matter content in coal mine dust is > 50%, the thickness of the diffusion adsorption layer is 4 - 6 mm, such as 4 mm, 5 mm, 6 mm, etc., the thickness of the depth filtration layer is 1.5 - 2.5 mm, such as 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.5 mm, etc., and the thickness of the depth purification layer is 0.8 - 1.2 mm, such as 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, etc.

[0041] In some embodiments of the present application, when the concentration of coal mine dust > 1500 mg / m 3 When the inorganic mineral content in coal mine dust is > 50%, the thickness of the diffusion adsorption layer is 5 - 8 mm, such as 5 mm, 6 mm, 7 mm, 8 mm, etc., the thickness of the depth filtration layer is 2 - 3 mm, such as 2 mm, 2.5 mm, 1.7 mm, 3 mm, etc., and the thickness of the depth purification layer is 1 - 2 mm, such as 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, etc.

[0042] In some embodiments of the present application, when the concentration of coal mine dust > 1500 mg / m 3 When the organic matter content in coal mine dust is > 50%, the thickness of the diffusion adsorption layer is 6 - 10 mm, such as 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc., the thickness of the depth filtration layer is 2 - 3 mm, such as 2 mm, 2.2 mm, 2.6 mm, 2.8 mm, 3 mm, etc., and the thickness of the depth purification layer is 1 - 1.5 mm, such as 1 mm, 1.2 mm, 1.3 mm, 1.5 mm, etc.

[0043] In some embodiments of the present application, when the particles constituting the coal mine dust contain oxygen-containing functional groups, the diffusion adsorption layer is subjected to plasma grafting modification to introduce carboxyl groups, and a composite coating of silica and polyethyleneimine is coated on the depth filtration layer.

[0044] In some embodiments of the present application, when the particles constituting the coal mine dust contain iron elements, magnetic nanocomposites are carried out in the diffusion adsorption layer, and a composite coating of graphene and polydopamine is coated on the depth filtration layer.

[0045] The technical solution of the present application will be further described below with specific embodiments.

[0046] Example 1

[0047] A filter element includes a metal mesh layer with a pore size of 40 μm arranged in layers, a diffusion adsorption layer composed of an electret meltblown cloth with a thickness of 5 mm and a glass fiber filter paper, a nanofiber depth filtration layer with a thickness of 1 mm, and a metal-organic framework depth purification layer with a thickness of 0.5 mm.

[0048] Example 2

[0049] A filter element includes a metal mesh layer with a pore size of 40 μm arranged in layers, a diffusion adsorption layer composed of an electret meltblown cloth with a thickness of 5 mm and a glass fiber filter paper, a nanofiber depth filtration layer with a thickness of 1.5 mm, and a metal-organic framework deep purification layer with a thickness of 0.8 mm.

[0050] Example 3

[0051] A filter element includes a metal mesh layer with a pore size of 40 μm arranged in layers, a diffusion adsorption layer composed of an activated carbon fiber layer with a thickness of 5 mm and an antistatic meltblown cloth, a nanofiber depth filtration layer with a thickness of 2 mm, and a photocatalytic TiO 2 coated ultra-high efficiency filter paper layer.

[0052] Example 4

[0053] A filter element includes a metal mesh layer with a pore size of 40 μm arranged in layers, a diffusion adsorption layer composed of an activated carbon fiber layer with a thickness of 7 mm and an antistatic meltblown cloth, a nanofiber depth filtration layer with a thickness of 2 mm, and a photocatalytic TiO 2 coated ultra-high efficiency filter paper layer.

[0054] Comparative Example 1

[0055] An N95 mask is composed of an outer layer of polypropylene non-woven fabric, a middle layer of polypropylene meltblown cloth, and a soft non-woven fabric inner layer, and can effectively block particles with a particle size greater than 0.3 μm and above.

[0056] Study on the filtration performance of the filter elements described in Examples 1-4 and Comparative Example 1 of this application:

[0057] Research method:

[0058] (1) Preparation of dust generation device

[0059] A dust generation device is equipped in a self-built experimental chamber for simulating the dust environment in a mine. The dust generation device consists of a pressure loading module and coal and rock blocks. When loading pressure, it can stably generate mine dust with different particle size distributions, and the components include coal dust, rock dust, etc. The minimum particle size of the particulate matter can reach dozens of microns or even a few microns. Through the temperature and humidity regulation system in the experimental chamber, the environmental conditions (such as temperature, humidity, etc.) are made similar to the real mine environment.

[0060] (2) Sample installation and testing process

[0061] ① Install the filter elements of Examples 1-4 and the N95 mask described in Comparative Example 1 on the same specification test fixtures respectively, and connect them to the air outlet position of the experimental chamber, ensuring good sealing to ensure that all the passing air can pass through the corresponding filter samples.

[0062] ② Turn on the dust generating device and set the initial dust concentration (for example, set it to a relatively high concentration, such as 50 mg / m 3 ) in the air. Adjust the gas flow rate to simulate the air velocity during normal breathing of miners, about 15 - 20 L / min), and let the dust-containing air flow through each filter sample. After continuous ventilation for 30 min, detect the dust concentration after filtration.

[0063] ③ Use a laser dust tester to collect samples at the air outlet of each filter sample, measure and record the remaining dust concentration in the air after filtration. At the same time, detect the pressure difference between the air inlet and the air outlet through the pressure sensor installed on the test fixture to obtain the filtration resistance.

[0064] To comprehensively evaluate the filtration performance, conduct multiple repeated tests on dust with different particle size ranges. The dust particle size can be divided into different intervals such as large particles (>10 μm), medium particles (1 - 10 μm), small particles (0.3 - 1 μm), and submicron particles (<0.3 μm). Adjust the dust generating device to generate dust with the corresponding particle size range for experiments respectively, and record the corresponding dust concentration after filtration and filtration resistance data after each experiment.

[0065] In addition, to simulate long-term use, after the above experiments are completed, continuously let the dust-containing air flow through each filter sample for a cumulative of 8 hours. During this period, repeat the detection of the dust concentration after filtration and the filtration resistance every 2 hours, and observe the change over time to evaluate the long-term filtration performance of each filter sample.

[0066] Research results

[0067] (1) Comparison of initial filtration efficiency

[0068] Large particle dust (>10 μm): The filtration efficiency of the filter cartridges in Examples 1 - 4 for large particle dust is close to 100%. This benefits from the metal mesh layer with a pore size of 40 μm on the outermost layer, which can play a good role in intercepting large particles. The filtration efficiency of Comparative Example 1 (N95 mask) for large particle dust is also relatively high, reaching about 98%, but it is slightly lower than that of the filter cartridges in the examples. The main reason is that the interception of the outer non-woven fabric is easily affected by the impact of large particle dust, and the protective effect is slightly inferior to the direct physical interception of the metal mesh layer.

[0069] Medium particle dust (1 - 10 μm): The filtration efficiency of the filter cartridges in Examples 1 - 4 is between 95% - 99%. Among them, the diffusion adsorption layer and the depth filtration layer work together to have a good capture effect on medium particle mine dust and organic dust. The filtration efficiency of Comparative Example 1 (N95 mask) is about 90% - 93%, mainly relying on the physical interception and electrostatic adsorption of the middle meltblown cloth layer, but the overall effect is slightly weaker than that of the filter cartridges in the examples.

[0070] Small particulate dust (0.3 - 1μm): The filtration efficiency of the filter elements in Examples 1 - 4 can still remain above 90%. The nanofiber membrane in the deep filtration layer and the relevant materials in the deep purification layer have further interception and adsorption effects on the dust in this particle size range. The filtration efficiency of Comparative Example 1 (N95 mask) for this part of the particle size dust is roughly around 85% - 90%. As the dust particle size becomes smaller and the content of organic particles in the dust increases, its filtration effect begins to show an obvious gap compared with the filter element of the example.

[0071] Sub - micron particles (<0.3μm): The filter elements in Examples 1 - 4 show different degrees of advantages, and the filtration efficiency is around 70% - 85%. Different examples vary due to the differences in the materials of the deep purification layer. In Examples 3 and 4, the ultra - high - efficiency filter paper layer with a photocatalytic TiO 2 coating has a relatively better filtration effect on sub - micron particles. While Comparative Example 1 (N95 mask) has almost no filtration effect, particles <0.3μm can still penetrate the N95 mask and reach the air outlet. The reason is that the melt - blown cloth layer has limited interception and adsorption ability for sub - micron particles.

[0072] (2) Comparison of long - term filtration performance

[0073] During the experiment of continuous ventilation for 8 hours to simulate long - term use, the decline in the filtration efficiency of the filter elements in Examples 1 - 4 is relatively small. In the initial few hours, a relatively high filtration level can be basically maintained. As time goes by, the decline in the filtration efficiency of dust in each particle size range is approximately between 5% - 15%. This is mainly due to the synergistic effect of its multi - layer structure and the long - term adsorption characteristics of some materials in the deep purification layer. Although the filtration resistance increases to a certain extent, it is still within an acceptable range and will not cause too much obstruction to normal air circulation.

[0074] The decline in the filtration efficiency of Comparative Example 1 (N95 mask) is more obvious. Especially after 4 hours of use, the decline in the filtration efficiency of dust in each particle size range can reach about 20% - 30%. This is because the electrostatic adsorption effect of its melt - blown cloth weakens continuously as more dust is adsorbed, forming a dust breakthrough. At the same time, it causes a sharp rise in the filtration resistance, making it difficult to breathe, which greatly affects its feasibility of continuous use.

[0075] (3) Comprehensive evaluation

[0076] From the perspective of the overall filtration performance, the filter elements in Examples 1 - 4 are superior to Comparative Example 1 (N95 mask) in terms of the filtration efficiency of dust in different particle sizes, long - term filtration ability, and dealing with particulate matter with complex components in the mine. They are more suitable for use in the environment of mine organic - inorganic composite dust and long - term operation, and can provide more reliable and continuous dust filtration protection for users.

[0077] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Variations, modifications, substitutions, and alterations made by those of ordinary skill in the art to the above embodiments are all within the scope of protection of the present invention.

Claims

1. A filter element, characterized in that: It includes a metal mesh, a diffusion adsorption layer, a deep filtration layer and a deep purification layer arranged in layers; The diffusion adsorption layer includes one or more of glass fiber filter paper, activated carbon fiber layer, electret melt-blown cloth and antistatic melt-blown cloth; The depth filtration layer includes one or more of high efficiency air filter paper, nanofiber membrane and ultrafine glass fiber filter paper; The deep purification layer includes one or more of ultra-high efficiency air filter paper, graphene-based composite membrane, metal organic framework, and photocatalytic TiO2 coated ultra-high efficiency filter paper.

2. The filter element according to claim 1, characterized in that: The pore size of the metal mesh is 35-45 μm; And / or, the diffusion adsorption layer has a thickness of 0.3-10 mm; And / or, the depth filtration layer has a thickness of 0.1-3 mm; And / or, the thickness of the deep purification layer is 0.05-2 mm.

3. Application of the filter element according to any one of claims 1 to 2 in equipment for filtering coal mine dust.

4. A coal mine dust filtering device, characterized in that: The invention comprises the filter element as described in any one of claims 1 to 2.

5. The coal mine dust filtering equipment according to claim 4, characterized in that: When the content of inorganic minerals in coal mine dust is greater than 50%, the diffusion adsorption layer is a composite layer of electret meltblown cloth and glass fiber filter paper, the deep filtration layer is a nanofiber membrane layer, and the deep purification layer is a metal organic framework layer.

6. The coal mine dust filtering equipment according to claim 4, characterized in that: When the organic matter content in the coal mine dust is greater than 50%, the diffusion adsorption layer is an activated carbon fiber layer and an antistatic melt-blown cloth composite layer, the deep filtration layer is a nanofiber membrane layer, and the deep purification layer is a photocatalytic TiO2 coated ultra-high efficiency filter paper layer.

7. The coal mine dust filtering equipment according to any one of claims 5-6, characterized in that: When the concentration of coal mine dust is 1000-1500mg / m 3 When the content of inorganic minerals in the coal mine dust is greater than 50%, the thickness of the diffusion adsorption layer is 3-5 mm, the thickness of the deep filtration layer is 1-2 mm, and the thickness of the deep purification layer is 0.5-1 mm; And / or, when the concentration of coal mine dust is 1000-1500mg / m 3 When the organic matter content in the coal mine dust is greater than 50%, the thickness of the diffusion adsorption layer is 4-6 mm, the thickness of the deep filtration layer is 1.5-2.5 mm, and the thickness of the deep purification layer is 0.8-1.2 mm.

8. The coal mine dust filtering equipment according to any one of claims 5-6, characterized in that: When the concentration of coal mine dust is greater than 1500mg / m 3 When the content of inorganic minerals in the coal mine dust is greater than 50%, the thickness of the diffusion adsorption layer is 5-8 mm, the thickness of the deep filtration layer is 2-3 mm, and the thickness of the deep purification layer is 1-2 mm; and / or, when the concentration of coal mine dust is greater than 1500 mg / m 3 When the organic matter content in the coal mine dust is greater than 50%, the thickness of the diffusion adsorption layer is 6-10 mm, the thickness of the deep filtration layer is 2-3 mm, and the thickness of the deep purification layer is 1-1.5 mm.

9. The coal mine dust filtering equipment according to claim 4, characterized in that: When the particles constituting the coal mine dust contain oxygen-containing functional groups, the diffusion adsorption layer is modified by plasma grafting to introduce carboxyl groups, and a composite coating of silica and polyethyleneimine is applied to the depth filtration layer.

10. The mineral dust filtering equipment according to claim 4, characterized in that: When the particles constituting the coal mine dust contain iron, magnetic nanocomposites are carried out in the diffusion adsorption layer, and a composite coating of graphene and polydopamine is applied in the depth filtration layer.