A purification material for reducing the concentration of particulate matter in ambient air and a method for preparing the same

Abstract

The application relates to the technical field of air purification materials, and provides a purification material for reducing the concentration of particulate matters in ambient air and a preparation method thereof. The preparation method comprises the following steps: mixing polyester fibers and cellulose fibers, and then sequentially performing webbing treatment and reinforcement treatment to obtain a fiber framework; coating a modified liquid on at least part of the surface of the fiber framework to obtain a modified fiber framework; atomizing and spraying a dust-locking dispersion liquid to the surface of the modified fiber framework, and sequentially performing drying treatment and shaping treatment to obtain the purification material; wherein the liquid amount of the dust-locking dispersion liquid is 2-8 g / m 2 When the particulate matters contact the purification material, the particulate matters can be captured and stably kept in the material, so that the possibility of the particulate matters being suspended again under the action of airflow disturbance, vibration or reverse airflow is reduced, the particulate matter keeping capacity is improved, the air passing property is good, and the risk of pressure drop increase is reduced.

Description

Technical Field

[0001] This invention relates to the field of air purification materials technology, and more specifically, to a purification material for reducing the concentration of particulate matter in ambient air and its preparation method. Background Technology

[0002] With the continuous development of urbanization and industrial activities, particulate matter pollution in ambient air has received increasing attention. Particulate matter in the air typically includes dust, smoke, pollen, carbon black particles, and fine particulate matter, with a wide range of particle sizes. Some fine particles can remain suspended in the air for extended periods and enter indoor ventilation systems, air purification equipment, or the human breathing zone with airflow. Therefore, filtration or purification materials used to reduce the concentration of particulate matter in ambient air have wide-ranging applications in building ventilation, indoor air purification, public place air treatment, and general environmental particulate matter control.

[0003] Existing air particulate matter purification materials mostly use non-woven fabrics, fiber felts, filter paper, melt-blown materials, or composite fiber materials as the basic filter media. These materials typically rely on the inter-fiber channels to capture airborne particulate matter through inertial collision, interception, diffusion deposition, or electrostatic adsorption. To further enhance the retention capacity of particulate matter in the filter material, adhesives or other components can be applied to the surface of the purification material. However, this method can easily cause pore shrinkage or local blockage, increasing the pressure drop of the filter material. In severe cases, it can even cause already adsorbed particulate matter to detach, resulting in secondary pollution.

[0004] Therefore, how to improve the stability of particulate matter after it is captured, while maintaining the interconnected channels of the fiber skeleton and low air resistance, remains a problem that needs to be solved in the field of ambient air particulate matter purification materials. Summary of the Invention

[0005] The present invention aims to provide a purification material for reducing the concentration of particulate matter in ambient air and a method for preparing the same.

[0006] To address the above problems, this invention provides a method for preparing a purification material that reduces the concentration of particulate matter in ambient air, comprising the following steps: S100: Polyester fiber and cellulose fiber are mixed and then subjected to web laying and reinforcement treatments in sequence to obtain a fiber skeleton; S200. The modified liquid is applied to at least a portion of the surface of the fiber skeleton to obtain the modified fiber skeleton. S300: The dust-locking dispersion is atomized and sprayed onto the surface of the modified fiber skeleton, and then dried and shaped in sequence to obtain the purification material; The loading rate of the dust-locking dispersion is 2~8 g / m³. 2 .

[0007] In the above technical solution, the preparation method of the dust-locking dispersion in S300 includes the following steps: S301. Mix glycerin, PEG-400 and sorbitol aqueous solution to obtain a low-volatility dust-locking liquid; S302. After pre-drying the liquid storage particles, add them to the low-volatility dust-locking liquid and stir to obtain liquid-carrying storage particles. S303. Add a fixed component to the carrier liquid storage microparticles and mix to obtain a dust-locking dispersion.

[0008] In any of the above technical solutions, the mass ratio of glycerol, PEG-400 and sorbitol aqueous solution is 1:(0.5~2):(0.2~1); and / or the mass ratio of the reservoir microparticles to glycerol is (1.5~2):1; and / or the mass ratio of the fixed component to glycerol is (4~10):1.

[0009] In any of the above technical solutions, the temperature of the pre-drying treatment is 60~100℃ and the time is 30~120min; and / or the speed of the stirring treatment is 300~1000rpm and the time is 20~60min.

[0010] In any of the above technical solutions, the particle size of the liquid storage particles is 5~20μm; and / or the liquid storage particles include at least one or a combination of diatomaceous earth, porous silica, sepiolite and attapulgite; and / or the fixed component includes at least one or a combination of aqueous polyurethane emulsion and acrylic emulsion.

[0011] In any of the above technical solutions, in S300, the drying temperature is 50~90℃ and the time is 10~60min; and / or the shaping treatment is to place the product at 25~40℃ and relative humidity of 40~70% for 6~24h.

[0012] In any of the above technical solutions, in S200, the modified liquid, by mass, includes: 2-10 parts of film-forming matrix, 1-8 parts of inorganic filler, 0.1-0.5 parts of dispersant, and 100 parts of deionized water; wherein, the film-forming matrix includes chitosan or cationic starch; the inorganic filler includes at least one or a combination of diatomaceous earth, nano-silica, and zeolite powder; and the pH of the modified liquid is 4-7.5.

[0013] In any of the above technical solutions, in S200, applying the modified liquid to at least a portion of the fiber skeleton includes: applying the modified liquid to at least a portion of the fiber skeleton surface by padding, and controlling the roll-up rate to be 60-120%; or spraying the modified liquid onto the fiber skeleton surface, and drying it at 50-80℃ for 10-40 minutes after spraying, with the amount of modified liquid applied being 5-20 g / m². 2 .

[0014] In any of the above technical solutions, S100 and S200 further include: S110. Pre-treat the fiber skeleton; Pretreatment includes corona treatment, plasma treatment, weak alkali treatment, or deionized water cleaning and drying.

[0015] The present invention also provides a purification material for reducing the concentration of particulate matter in ambient air, which is prepared by any of the preparation methods described above.

[0016] Beneficial effects This invention provides a purification material for reducing particulate matter concentration in ambient air and its preparation method. A fiber skeleton is formed by mixing polyester and cellulose fibers, giving the purification material interconnected channels and a stable support structure. A modified liquid is applied to the surface of the fiber skeleton, creating a modified layer with polarity and roughness, increasing the contact probability and initial trapping ability between particulate matter and the fiber surface, and providing an anchoring basis for the stable deposition of the subsequent dust-locking dispersion. The low-volatility dust-locking liquid enters the channels of the storage microparticles, forming liquid-carrying storage microparticles. These microparticles are then fixed to the modified fiber skeleton by a fixed component, allowing the low-volatility dust-locking liquid to be confined and retained by the storage microparticles, reducing its free flow, migration, and seepage on the fiber surface, and lowering the possibility of forming a continuous liquid film. After contacting the purification material, particulate matter is not only trapped but also relatively stably retained within the material, reducing the possibility of re-suspension under airflow disturbance, vibration, or reverse airflow. Furthermore, while improving particulate matter retention capacity, good air permeability is maintained, reducing the risk of increased pressure drop. Detailed Implementation

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, a detailed description of specific embodiments of the present invention will be provided below.

[0018] Unless otherwise specified, all reagents and raw materials used in this invention are commercially available. Experimental methods in the following examples that do not specify particular conditions should be performed according to conventional methods and conditions, or as selected in the product instructions.

[0019] Air particulate matter purification materials typically use non-woven fabrics, fiber felts, filter paper, meltblown materials, or composite fiber materials as the basic filter medium. They rely on the pores between the fibers to capture airborne particulate matter through inertial collision, interception, diffusion deposition, or electrostatic adsorption. In related technologies, to further enhance the retention capacity of particulate matter in the filter material, adhesives or other components are often applied to the surface of the purification material to form a membrane layer that can adhere to the particulate matter. However, this membrane layer is prone to causing pore shrinkage or localized blockage, increasing the pressure drop of the filter material, and in severe cases, even causing the already adsorbed particulate matter to detach, resulting in secondary pollution.

[0020] This invention provides a purification material for reducing the concentration of particulate matter in ambient air and its preparation method. By forming a modified layer on the surface of a fiber skeleton and spraying a dust-locking dispersion containing liquid-carrying microparticles and fixed components onto the modified fiber skeleton surface, the low-volatility dust-locking liquid is confined and retained by the liquid-carrying microparticles and fixed to the fiber skeleton by the fixed components. This can improve the stability of particulate matter capture while maintaining the air permeability of the fiber skeleton, and reduce the problems of pore blockage and pressure drop caused by continuous liquid film or continuous adhesive film.

[0021] Specifically, this invention provides a method for preparing a purification material that reduces the concentration of particulate matter in ambient air, comprising the following steps: S100: Polyester fiber and cellulose fiber are mixed and then subjected to web laying and reinforcement treatments in sequence to obtain a fiber skeleton; S200. The modified liquid is applied to at least a portion of the surface of the fiber skeleton to obtain the modified fiber skeleton. S300: The dust-locking dispersion is atomized and sprayed onto the surface of the modified fiber skeleton, and then dried and shaped in sequence to obtain the purification material; The loading rate of the dust-locking dispersion is 2~8 g / m³. 2 .

[0022] Preferably, since particulate filtration does not rely on completely blocking the air, but rather on the inertial collision, interception, and diffusion contact between particles and fibers as air passes through a porous fiber network, and polyester fibers have good mechanical support and dimensional stability, ensuring that the material does not easily collapse under airflow, while cellulose fibers contain many polar groups on their surface, which is beneficial for the adhesion of subsequent modification liquids; therefore, in step S100, polyester fibers and cellulose fibers are used as raw materials for the fiber skeleton in a ratio of (2~6):1. First, they are opened, then mixed and combed, and then the fibers are interwoven to form a three-dimensional porous structure through a web-laying process. Then, a reinforcement process is used to stabilize the fiber intersections, thereby forming a filter skeleton with a certain strength and interconnected channels. The reinforcement process preferably includes any one of needle punching, hot air bonding, or hydroentangling reinforcement. The resulting fiber skeleton ensures air permeability while providing the basic space for inertial collision, interception, and diffusion deposition of particles, and also provides a bondable fiber interface for subsequent surface modification.

[0023] Preferably, the fiber skeleton obtained in step S100 has a high proportion of polyester fibers, so its surface is relatively inert. Particles may bounce off or be carried away by the airflow after contact. In order to improve the polarity, roughness and interfacial bonding force of the fiber surface, so as to increase the number of contact points between particles and fibers and make it easier for the subsequent dust-locking dispersion to anchor, in step S200, a modified liquid is applied to at least part of the surface of the fiber skeleton. The modified liquid can change the interfacial state of the fiber skeleton surface, so that the originally smooth or inert fiber surface is transformed into a surface that is easier to contact and adhere to particles and dust-locking dispersion. After the modified liquid covers the fiber surface, it can improve the polarity, roughness or local adhesion of the fiber surface, so that particles are more likely to stay on the fiber surface, fiber intersection or pore wall area after entering the fiber skeleton with the airflow, thereby enhancing the initial capture probability of particles and improving the adhesion stability of the subsequent dust-locking dispersion on the fiber skeleton, avoiding the problems of poor adhesion, local loss or unstable distribution after the dust-locking components are directly sprayed.

[0024] Furthermore, between S100 and S200, there is also: S110. Pre-treat the fiber skeleton.

[0025] Preferably, in order to improve the treatment effect of the modified liquid in step S200, the fiber skeleton needs to be pretreated before step S200 to improve the stability of the combination between the fiber skeleton and the modified liquid. The pretreatment includes corona treatment, plasma treatment, weak alkali treatment or deionized water cleaning and drying treatment. After pretreatment, the polar groups on the fiber surface increase, which is conducive to the uniform adhesion of the modified liquid on the fiber surface.

[0026] Preferably, in S200, the modified liquid, by mass, comprises: 2-10 parts of film-forming matrix, 1-8 parts of inorganic filler, 0.1-0.5 parts of dispersant, and 100 parts of deionized water. Since the surface of polyester fibers is relatively inert, the dust-locking components tend to adhere poorly when the dust-locking dispersion is directly sprayed. Although cellulose fibers have hydroxyl groups, film-forming components are still needed to improve surface bonding stability. Therefore, by forming a thin polar adhesion layer on the fiber surface through the film-forming matrix, inorganic fillers can be fixed to the fiber skeleton surface, giving the fiber skeleton a certain initial adhesion ability. The film-forming matrix includes chitosan or cationic starch. Chitosan and cationic starch contain polar groups such as amino and hydroxyl groups, which can form hydrogen bonds with cellulose fibers and also improve the affinity of the polyester fiber surface. Inorganic fillers first create an uneven fiber surface, increasing its roughness. This makes it easier for particulate matter and the dust-locking dispersion to remain at fiber intersections, pore wall areas, or micro-recesses. The inorganic fillers include at least one or a combination of diatomaceous earth, nano-silica, and zeolite powder. Diatomaceous earth, with its porous structure and irregular surface, can form micro-protrusions and micro-recesses on the fiber surface, making it easier for airborne particulate matter to be intercepted and retained. Nano-silica, with its small particle size and large specific surface area, can increase the micro-roughness of the fiber surface and the number of polar contact sites. Zeolite powder, with its porous structure and strong surface polarity, is beneficial for increasing the contact and adsorption probability of particulate matter. Dispersants help maintain the uniform dispersion of the inorganic fillers in the aqueous modified liquid, preventing agglomeration.

[0027] Furthermore, an appropriate amount of pH adjuster needs to be added to the modified solution to adjust the pH of the modified solution to the range of 4 to 7.5. When chitosan is selected as the film-forming matrix, chitosan should first be dissolved in an aqueous acetic acid solution with a mass fraction of 1.5 to 2%, and then inorganic filler should be added and dispersed at a speed of 500 to 2000 rpm for 20 to 60 minutes. The pH of the prepared modified solution is preferably controlled in the range of 4 to 5.8. When cationic starch is used as the film-forming matrix, the pH is preferably adjusted to 5 to 7.5.

[0028] Furthermore, in S200, applying the modified liquid to at least a portion of the surface of the fiber skeleton includes: applying the modified liquid to at least a portion of the surface of the fiber skeleton by padding. Since the fiber skeleton typically has interconnected channels and numerous fiber intersections, air particles are not only captured on the outer surface of the material, but collide, intercept, and deposit with the fiber surface, pore wall area, and fiber intersections after entering the channels. Through padding, the modified liquid can wet the inner and outer surfaces of the fiber skeleton, allowing the film-forming matrix and inorganic filler to adhere to more fiber surfaces. Excess modified liquid is then removed by roller pressing, which avoids excessive retention of modified liquid in the pores, resulting in a more complete distribution of the modified layer. The internal pores also possess the ability to initially capture particles and anchor the subsequent dust-locking dispersion liquid. The roll-off rate is 60-120%, which allows the modified liquid to fully penetrate the fiber skeleton, while removing excess free liquid by roller pressing to avoid the formation of an excessively thick or continuous pore-clogging layer. Alternatively, the modified liquid can be sprayed onto the fiber skeleton surface, where it is deposited as droplets. The film-forming matrix and inorganic fillers adhere to the fiber surface with the droplets, reducing the overall filling of the pores by the modified liquid and lowering the risk of increased pressure drop caused by excessive modified liquid entering the internal pores. After spraying, drying at 50-80℃ for 10-40 minutes allows the film-forming matrix to form a stable adhesion layer and fixes the inorganic fillers to the fiber surface, thus forming a stable modified layer. The amount of modified liquid applied is 5-20 g / m³. 2 It can effectively form a modified layer while avoiding excessive clogging of pores.

[0029] Preferably, in step S300, the dust-locking dispersion is atomized and sprayed onto the surface of the modified fiber skeleton, so that the dust-locking dispersion is dispersed and deposited in the form of fine droplets on the surface of the modified fiber skeleton and part of the pore area, rather than continuously covering the fiber pores over a large area as in impregnation or large-scale coating; after the dust-locking dispersion is deposited, it is dried to remove volatile media, so that the dust-locking components remain on the fiber surface; the drying temperature is 50~90℃ and the time is 10~60min, so that the water or volatile dispersion media in the dust-locking dispersion evaporates appropriately, and promotes the fixed components to form a stable bond on the surface of the modified fiber skeleton, thereby fixing the liquid-carrying storage particles on the fiber surface, fiber intersections or pore wall areas. Further stabilization treatment stabilizes the distribution and bonding of the dust-locking components on the fiber skeleton. This stabilization process involves equilibrating at 25–40°C and 40–70% relative humidity for 6–24 hours, further stabilizing the film-forming state of the fixed components, strengthening the bond between the liquid-carrying particles and the modified fiber skeleton, and ensuring a more stable retention of the low-volatility dust-locking liquid within the pores of the liquid-carrying particles. The resulting dust-locking phase is not a continuous film on the surface of the modified fiber skeleton, but rather a discontinuous, island-like dust-locking phase. This allows particles to be captured by the fiber skeleton and modified surface, further adhered and retained by the dust-locking sites, reducing the likelihood of particles detaching or resuspending under airflow disturbances. Simultaneously, it maintains unobstructed airflow, minimizing the possibility of particle blockage in the fiber pores after the particles are fixed by the dust-locking phase.

[0030] Preferably, during the process of atomizing and spraying the dust-locking dispersion onto the surface of the modified fiber skeleton, the spraying pressure is 0.1~0.4MPa, the spraying distance is 10~30cm, and the spray particle size is 50~150μm. During the spraying process, a negative pressure of -0.5~-5kPa needs to be applied to the back of the modified fiber skeleton to form a weak pressure difference airflow in the thickness direction of the material, so that the dust-locking dispersion not only exists on the surface, but also enters the internal pore walls and fiber intersections, thereby improving the effective utilization rate in the thickness direction of the material.

[0031] Preferably, the loading rate of the dust-locking dispersion is 2~8 g / m³. 2 The amount of liquid applied refers to the actual mass of wet dispersion retained per unit area of ​​the material after the dust-locking dispersion is applied to the modified fiber skeleton and treated with negative pressure suction or free liquid removal. When the amount of dust-locking dispersion retained is too low, the number of dust-locking sites on the fiber skeleton is insufficient, and there is not enough adhesion and retention area after the particles are captured, resulting in an insignificant anti-resuspension effect. When the amount of dust-locking dispersion retained is too high, the dust-locking dispersion is prone to clump or accumulate between fibers, causing pore narrowing or even local blockage, leading to increased air resistance. Therefore, the amount of dust-locking dispersion applied is 2~8 g / m². 2It can provide sufficient dust-locking sites, improve the stability of particulate matter after capture, and reduce the risk of pore blockage and pressure drop caused by excessive dust-locking dispersion.

[0032] Furthermore, in S300, the preparation method of the dust-locking dispersion includes the following steps: S301. Mix glycerin, PEG-400 and sorbitol aqueous solution to obtain a low-volatility dust-locking liquid; S302. After pre-drying the liquid storage particles, add them to the low-volatility dust-locking liquid and stir to obtain liquid-carrying storage particles. S303. Add a fixed component to the carrier liquid storage microparticles and mix to obtain a dust-locking dispersion.

[0033] Preferably, in step S301, glycerol, PEG-400, and sorbitol aqueous solution are mixed evenly. Glycerol has low volatility, hygroscopicity, and a certain viscosity, which can provide a basis for wetting and adhesion when particles come into contact. PEG-400 can adjust the viscosity and flowability of the system, allowing the dust-locking liquid to enter the pores of the reservoir particles without excessive flow. The sorbitol aqueous solution has moisturizing and thickening effects, helping to maintain the wet state of the dust-locking liquid. After compounding glycerol, PEG-400, and sorbitol aqueous solution, the resulting low-volatility dust-locking liquid can form a local liquid meniscus when particles come into contact, providing a basis for subsequent capillary bridge dust locking. The mass ratio of glycerol, PEG-400, and sorbitol aqueous solution is 1:(0.5~2):(0.2~1), which allows the low-volatility dust-locking liquid to enter the interior of the reservoir particles and maintain appropriate wetting and adhesion capabilities during subsequent use.

[0034] Preferably, in step S302, the storage microparticles are first pre-dried, and then added to the low-volatility dust-locking liquid and stirred, so that the low-volatility dust-locking liquid enters the pores of the storage microparticles. Since the storage microparticles themselves have a porous structure, but their pores may contain moisture or adsorbed water, if they are not pre-dried, the moisture will occupy the pore space, reducing the amount of dust-locking liquid entering and maintaining stability. The pre-drying temperature is 60~100℃ and the time is 30~120min, which can fully remove free water and adsorbed water from the surface and pores of the storage microparticles, and improve the storage microparticles' ability to absorb the low-volatility dust-locking liquid. After pre-drying, the pores of the liquid-holding microparticles more easily absorb the low-volatility dust-locking liquid. Further agitation ensures thorough contact between the microparticles and the dust-locking liquid. Capillary suction and wetting penetration allow the dust-locking liquid to penetrate the interior of the microparticles, forming liquid-carrying reservoirs. This prevents the low-volatility dust-locking liquid from existing as a free liquid; instead, it is confined and held within the microparticles. When subsequently sprayed onto the fiber matrix, the dust-locking liquid is less likely to flow, migrate, or spread into a continuous liquid film over a large area, instead remaining concentrated within and around the microparticles, thus forming localized dust-locking sites. Agitation speed of 300–1000 rpm for 20–60 minutes ensures sufficient contact between the pre-dried microparticles and the low-volatility dust-locking liquid, promoting its entry into the pores of the microparticles. A mass ratio of microparticles to glycerin of (1.5–2):1 is beneficial for sufficient liquid loading in the microparticles and prevents excessive liquid release. The storage microparticles have a particle size of 5-20 μm, which facilitates uniform spraying of the storage microparticles with the dust-locking dispersion and stable adhesion to the fiber surface, fiber intersections, or pore wall areas, while providing sufficient local storage space. The storage microparticles include at least one or a combination of diatomaceous earth, porous silica, sepiolite, and attapulgite. Diatomaceous earth has a natural porous structure and irregular surface, which can adsorb low-volatility dust-locking liquid and form rough dust-locking sites; porous silica has a large specific surface area and contains silanol groups on its surface, which is beneficial for wetting and retaining polar liquids such as glycerol and PEG-400; sepiolite and attapulgite have fibrous or chain-like pore structures, which can adsorb and retain liquids and help improve the thixotropy and stability of the dispersion system; using the above-mentioned types of storage microparticles can transform the low-volatility dust-locking liquid from a free liquid state to a liquid-carrying state confined by pores, thereby reducing subsequent migration and continuous liquid film formation.

[0035] Preferably, in step S303, adding a fixing component to the liquid-carrying microparticles is to enable the microparticles to subsequently adhere and be fixed. Although the liquid-carrying microparticles can store the dust-locking liquid, if they are directly sprayed onto the modified fiber skeleton, problems such as particle detachment, unstable distribution, or being carried away by airflow may occur. The fixing component can form a flexible bonding structure during subsequent drying and setting processes, fixing the liquid-carrying microparticles to the fiber surface, fiber intersections, or pore wall areas, enabling them to stably perform their dust-locking function. If the fixing component is added first, and then the liquid-carrying microparticles absorb the dust-locking liquid, the fixing component may coat the surface of the liquid-carrying microparticles, hindering the low-volatility dust-locking liquid from entering the pores, causing more of the dust-locking liquid to remain on the outside, increasing free liquid migration and adhesion. To mitigate the risk of continuous film formation, the solution involves first allowing the reservoir microparticles to absorb the locking liquid before adding the fixing component. This ensures that the locking liquid preferentially enters the reservoir microparticles, and the fixing component then provides external fixation. The fixing component includes at least one or a combination of aqueous polyurethane emulsion and acrylic emulsion. Both aqueous polyurethane and acrylic emulsions possess good film-forming properties, flexibility, and adhesion to fiber surfaces. Aqueous polyurethane emulsions, after film formation, exhibit flexibility and abrasion resistance, enabling them to maintain the stability of the reservoir microparticles under airflow scouring. The acrylic emulsion preferably uses a low Tg (glass transition temperature) acrylic emulsion, with Tg ≤ 0℃, which provides good adhesion and film-forming controllability, enhancing the bond between the reservoir microparticles and the modified fiber skeleton. The mass ratio of the fixing component to glycerol is (4~10):1, ensuring that the reservoir microparticles are stably fixed on the modified fiber skeleton while avoiding the formation of excessive continuous films.

[0036] Preferably, when the purification material prepared by the preparation method described in this invention is used, after airborne particulate matter enters the fiber skeleton pores, it is first intercepted, collided with, and initially adsorbed by the fiber skeleton and the modified layer. When the particulate matter comes into contact with the area where the liquid-carrying particles are located, the low-volatility dust-locking liquid held in the liquid-carrying particles can form a local liquid meniscus between the particulate matter and the liquid-carrying particles, thereby generating a capillary liquid bridge effect. This capillary liquid bridge can improve the holding force between the particulate matter and the purification material through surface tension and capillary negative pressure, so that the particulate matter is not only intercepted, but also locally fixed.

[0037] This invention also provides a purification material for reducing the concentration of particulate matter in ambient air, prepared using any of the methods described above. Therefore, it possesses all the beneficial effects of this invention, which will not be elaborated further here.

[0038] Example 1

[0039] This embodiment provides a modified liquid, which, by mass, comprises: 2 parts chitosan, 1 part diatomaceous earth, 0.1 parts dispersant, 100 parts deionized water, and has a pH of 4.

[0040] Example 2

[0041] This embodiment provides a modified liquid, which, by mass, comprises: 10 parts cationic starch, 8 parts nano silica, 0.5 parts dispersant, 100 parts deionized water, and has a pH of 7.5.

[0042] Example 3

[0043] This embodiment provides a modified liquid, which, by mass, comprises: 8 parts chitosan, 6 parts zeolite powder, 0.3 parts dispersant, 100 parts deionized water, and has a pH of 5.

[0044] The solid content, viscosity at 25°C, surface tension, and sedimentation rate after standing for 24 hours were measured for the modified liquids of Examples 1-3, and the results are shown in Table 1.

[0045] Table 1

[0046] As shown in Table 1, the modified liquids of Examples 1-3 all exhibit moderate solid content, good fluidity, adjustable wetting properties, and low sedimentation rates, indicating good compatibility among the film-forming matrix, inorganic filler, and dispersant, and suitable pH conditions. This modified liquid can stably disperse inorganic fillers and is suitable for coating the fiber skeleton surface to form a modified layer, thus providing a foundation for the subsequent adhesion of the dust-locking dispersion and the initial capture of particulate matter.

[0047] Example 4

[0048] This embodiment provides a method for preparing a dust-locking dispersion, including the following steps: S301. Glycerin, PEG-400 and sorbitol aqueous solution are mixed in a mass ratio of 1:0.5:0.2 to obtain a low-volatility dust-locking liquid; S302. After pre-drying the storage microparticles at 60°C for 30 min, add them to a low-volatility dust-locking liquid and stir at 300 rpm for 20 min to obtain the liquid-carrying storage microparticles. S303. Add aqueous polyurethane emulsion to the carrier liquid storage microparticles, and mix to obtain a dust-locking dispersion. The liquid storage particles are diatomaceous earth with a particle size of 5 μm, the mass ratio of liquid storage particles to glycerol is 1.5:1, and the mass ratio of waterborne polyurethane emulsion to glycerol is 4:1.

[0049] Example 5

[0050] This embodiment provides a method for preparing a dust-locking dispersion, including the following steps: S301. Mix glycerin, PEG-400 and sorbitol aqueous solution in a mass ratio of 1:2:1 to obtain a low-volatility dust-locking liquid; S302. After pre-drying the liquid storage particles at 100°C for 120 min, add them to a low-volatility dust-locking liquid and stir at 1000 rpm for 60 min to obtain liquid-carrying storage particles. S303. Add acrylic emulsion to the carrier liquid storage microparticles, and mix to obtain a dust-locking dispersion. The reservoir microparticles are porous silica with a particle size of 20 μm. The mass ratio of the reservoir microparticles to glycerol is 2:1, the mass ratio of the acrylic emulsion to glycerol is 10:1, and the Tg of the acrylic emulsion is ≤0℃.

[0051] Example 6

[0052] This embodiment provides a method for preparing a dust-locking dispersion, including the following steps: S301. Glycerin, PEG-400 and sorbitol aqueous solution are mixed in a mass ratio of 1:1:0.5 to obtain a low-volatility dust-locking liquid; S302. After pre-drying the liquid storage particles at 80°C for 100 min, add them to a low-volatility dust-locking liquid and stir at 800 rpm for 40 min to obtain liquid-carrying storage particles. S303. Add acrylic emulsion to the carrier liquid storage microparticles, and mix to obtain a dust-locking dispersion. The reservoir microparticles are sepiolite with a particle size of 10 μm, the mass ratio of reservoir microparticles to glycerol is 1.5:1, the mass ratio of acrylic emulsion to glycerol is 8:1, and the Tg of the acrylic emulsion is ≤0℃.

[0053] The viscosity, liquid absorption, liquid retention rate after centrifugation at 3000 rpm for 10 min, mass retention rate at 80℃, sedimentation rate after standing for 24 h, and sedimentation rate after standing for 7 d were measured for the dust-locking dispersions prepared in Examples 4-6. The results are shown in Table 2.

[0054] Table 2

[0055] As can be seen from Table 2, the dust-locking dispersions can all enable the storage particles to adsorb and retain the low-volatility dust-locking liquid. This indicates that the dust-locking dispersions obtained by the preparation method described in this invention can effectively absorb and stably retain the low-volatility dust-locking liquid by the storage particles. At the same time, by fixing the components to form a dispersion system suitable for spraying and subsequent fixation, the dust-locking dispersions can form a stable liquid-carrying storage particle dust-locking structure on the modified fiber skeleton during the subsequent preparation of purification materials, providing a reliable basis for the capillary liquid bridge dust-locking effect after particulate matter contact.

[0056] Example 7

[0057] This embodiment provides a method for preparing a purification material that reduces the concentration of particulate matter in ambient air, including the following steps: S100. Polyester fiber and cellulose fiber are mixed at a mass ratio of 2:1 and then subjected to web laying and reinforcement treatments in sequence to obtain a fiber skeleton. S200. The modified liquid of Example 1 is applied to at least a portion of the surface of the fiber skeleton by padding, with a roll-off rate of 60%, to obtain the modified fiber skeleton. S300. The dust-locking dispersion prepared in Example 4 is atomized and sprayed onto the surface of the modified fiber skeleton. The spraying pressure is 0.1 MPa, the spraying distance is 10 cm, and the spray particle size is 50 μm. During the spraying process, a negative pressure of -0.5 kPa needs to be applied to the back of the modified fiber skeleton. The material is dried at 50°C for 10 min and then placed at 25°C and 40% relative humidity for 6 h to obtain the purification material. The loading rate of the dust-locking dispersion is 2 g / m³. 2 .

[0058] Example 8

[0059] This embodiment provides a method for preparing a purification material that reduces the concentration of particulate matter in ambient air, including the following steps: S100. Polyester fiber and cellulose fiber are mixed at a mass ratio of 6:1 and then subjected to web laying and reinforcement treatments in sequence to obtain a fiber skeleton. S110. Corona treatment is applied to the fiber skeleton. S200. The modified liquid from Example 2 is sprayed onto the surface of the fiber skeleton, and then dried at 50°C for 10 minutes. The amount of modified liquid applied is 5 g / m². 2 A modified fiber skeleton was obtained; S300. The dust-locking dispersion prepared in Example 5 is atomized and sprayed onto the surface of the modified fiber skeleton. The spraying pressure is 0.4 MPa, the spraying distance is 30 cm, and the spray particle size is 150 μm. During the spraying process, a negative pressure of -5 kPa needs to be applied to the back of the modified fiber skeleton. The material is dried at 90°C for 60 min and then placed at 40°C and 70% relative humidity for 24 h to obtain the purification material. The loading rate of the dust-locking dispersion is 8 g / m³. 2 .

[0060] Example 9

[0061] This embodiment provides a method for preparing a purification material that reduces the concentration of particulate matter in ambient air, including the following steps: S100. Polyester fiber and cellulose fiber are mixed at a mass ratio of 4:1 and then subjected to web laying and reinforcement treatments in sequence to obtain a fiber skeleton. S110. Plasma treatment is applied to the fiber skeleton; S200. The modified liquid of Example 3 is applied to at least a portion of the surface of the fiber skeleton by padding, with a roll-off rate of 120%, to obtain the modified fiber skeleton. S300. The dust-locking dispersion prepared in Example 6 is atomized and sprayed onto the surface of the modified fiber skeleton. The spraying pressure is 0.3 MPa, the spraying distance is 20 cm, and the spray particle size is 100 μm. During the spraying process, a negative pressure of -2 kPa needs to be applied to the back of the modified fiber skeleton. The material is dried at 77°C for 40 min and then placed at 35°C and 50% relative humidity for 18 h to obtain the purification material. The loading rate of the dust-locking dispersion is 5 g / m³. 2 .

[0062] Example 10

[0063] This embodiment provides a method for preparing a purification material that reduces the concentration of particulate matter in ambient air, including the following steps: S100. Polyester fiber and cellulose fiber are mixed at a mass ratio of 5:1 and then subjected to web laying and reinforcement treatments in sequence to obtain a fiber skeleton. S110. The fiber skeleton is treated with a weak alkali. S200. The modified liquid from Example 3 is sprayed onto the surface of the fiber skeleton, and then dried at 80°C for 40 minutes. The amount of modified liquid applied is 20 g / m². 2 A modified fiber skeleton was obtained; S300. The dust-locking dispersion prepared in Example 6 is atomized and sprayed onto the surface of the modified fiber skeleton. The spraying pressure is 0.2 MPa, the spraying distance is 15 cm, and the spray particle size is 85 μm. During the spraying process, a negative pressure of -3 kPa needs to be applied to the back of the modified fiber skeleton. The material is dried at 85°C for 50 min and then placed at 35°C and 66% relative humidity for 18 h to obtain the purification material. The loading rate of the dust-locking dispersion is 6 g / m³. 2 .

[0064] Comparative Example 1 This comparative example provides a purification material, which is a fiber skeleton obtained by mixing polyester fiber and cellulose fiber in a mass ratio of 2:1 and then sequentially performing web laying and reinforcement treatment. The difference from Example 7 is that steps S200~300 are not included.

[0065] Comparative Example 2 This comparative example provides a purification material, which differs from Example 7 in that step S200 is omitted. In step S300, the dust-locking dispersion prepared in Example 4 is directly atomized and sprayed onto the surface of the fiber skeleton obtained in S100.

[0066] Comparative Example 3 This comparative example provides a purification material, which differs from Example 7 in that step S300 is omitted.

[0067] Comparative Example 4 This comparative example provides a purification material. The difference from Example 7 is that the dust-locking dispersion liquid of Example 4 is not used in step S300. Instead, the low-volatility dust-locking liquid obtained in step S301 of Example 4 is directly atomized and sprayed onto the surface of the modified fiber skeleton, and the amount of low-volatility dust-locking liquid applied is controlled to be the same as in Example 7.

[0068] Comparative Example 5 This comparative example provides a purification material. The difference from Example 7 is that the preparation method of the dust-locking dispersion used in step S300 is basically the same as that in Example 4, but the storage particles are not pre-dried in step S302.

[0069] Comparative Example 6 This comparative example provides a purification material. The difference between this material and Example 7 is that the preparation method of the dust-locking dispersion used in step S300 is basically the same as that in Example 4, but no aqueous polyurethane emulsion is added in step S303, that is, no fixed component is added.

[0070] Comparative Example 7 This comparative example provides a purification material, which differs from Example 7 in that negative pressure is not applied to the back of the modified fiber skeleton in step S300.

[0071] The purification materials in Examples 7-10 and Comparative Examples 1-7 were subjected to the following tests: PM2.5 and PM10 removal rates and initial pressure drop tests: Samples from Examples 7-10 and Comparative Examples 1-7 were cut into circular specimens with a diameter of 100 mm and installed in a filtration performance testing device. PM2.5 and PM10 particulate aerosols were generated using a standard particulate matter generator. The test wind speed was controlled at 0.3 m / s, the test temperature at 25°C, and the relative humidity at 50%. The mass concentrations of particulate matter upstream and downstream of the samples were measured, and the particulate matter removal rate was calculated according to the following formula: Particulate matter removal rate (%) = (C0 - C1) / C0 × 100% Where C0 is the mass concentration of particulate matter upstream of the sample, and C1 is the mass concentration of particulate matter downstream of the sample; At the same time, the initial pressure drop of the sample under the test wind speed was measured, and the test results are shown in Table 3.

[0072] Table 3

[0073] As shown in Table 3, the PM2.5 and PM10 removal rates of Examples 7-10 were significantly higher than those of Comparative Example 1, indicating that although the simple fiber skeleton has a basic interception function, its particulate matter removal capacity is limited. However, after treatment with the modified liquid and the introduction of the dust-locking dispersion, the particulate matter capture performance of the purification material was significantly improved. Compared with Comparative Example 2, the PM2.5 and PM10 removal rates of Example 7 were higher, indicating that the modified layer can improve the adhesion stability of the dust-locking dispersion on the fiber skeleton, allowing the liquid-carrying particles to participate more effectively in particulate matter capture. Compared to Example 3, Example 7 also showed an improved removal rate, indicating that the particle capture capacity was still limited when only the modified layer was used. The dust-locking phase formed by the dust-locking dispersion could further improve the particle capture effect. The particle removal rate of Comparative Example 4 was close to that of Example 7, but the initial pressure drop was significantly higher than that of Example 7. This indicates that although direct spraying of low-volatility dust-locking liquid can enhance particle adhesion, it is easy to cause liquid spreading or pore shrinkage, which increases air resistance. The present invention can improve the particle capture capacity while maintaining a low pressure drop by confining the low-volatility dust-locking liquid with liquid-storing microparticles.

[0074] Particulate matter retention rate and resuspension rate test: The samples of Examples 7-10 and Comparative Examples 1-7 were placed in a standard dust loading device to capture the same mass of standard dust. Then the samples were placed in a disturbance test device and purged with an airflow of 0.8 m / s for 10 min while low-intensity mechanical vibration was applied. The mass of particulate matter released during the purging process was collected, and the particulate matter retention rate and resuspension rate were calculated. The results are shown in Table 4.

[0075] Table 4

[0076] As shown in Table 4, the particulate matter retention rate and resuspension rate of Examples 7-10 are significantly better than those of the comparative examples, indicating that the purification material obtained by the present invention can not only capture particulate matter, but also effectively improve the retention stability of captured particulate matter. The particulate matter retention rate of Comparative Example 1 is only 52.8%, indicating that the particulate matter intercepted by the fiber alone is easily detached again under airflow disturbance and vibration conditions; the particulate matter retention rate of Comparative Example 3 is 70.2%, indicating that the modified layer can improve the initial adhesion ability, but it lacks the capillary liquid bridge dust-locking effect formed by the liquid-carrying storage particles, and the anti-resuspension ability is still insufficient; the particulate matter retention rate of Comparative Example 4 is 78.4%, indicating that when the low-volatile dust-locking liquid is directly present on the fiber surface, it is easy to migrate or spread locally, and cannot stably form dispersed dust-locking sites. However, the present invention uses liquid-carrying particles to lock low-volatile dust-locking sites. The confined retention of the dust-locking liquid can form more stable local capillary bridges when particles come into contact, thereby improving the particle retention rate. The particle retention rate of Comparative Example 5 is lower than that of Example 7, indicating that the pre-drying treatment is beneficial to improving the absorption and retention capacity of the reservoir microparticles for the low-volatility dust-locking liquid. The particle retention rate of Comparative Example 6 is further reduced, indicating that the fixing component plays an important role in the stable fixation of the reservoir microparticles on the fiber skeleton. The retention rate of Comparative Example 7 is lower than that of Example 7, indicating that negative pressure assistance is beneficial for the dust-locking dispersion to enter the pores and distribute at fiber intersections or pore wall areas.

[0077] Dust-locking fluid migration rate test: Samples from Examples 7-10 and Comparative Examples 1-7 were cut into 50mm × 50mm specimens, placed on clean glass slides, and left at 40°C and 50% relative humidity for 24 hours. The mass of liquid that migrated from the glass slides was weighed, and the dust-locking fluid migration rate was calculated according to the following formula: Dust-locking liquid migration rate (%) = (mass of migrated liquid / theoretical mass of low-volatile dust-locking liquid in the sample) × 100%; The results are shown in Table 5.

[0078] Table 5

[0079] As shown in Table 5, the migration rate of the dust-locking liquid in Examples 7-10 is less than 5%, indicating that the low-volatility dust-locking liquid can be well confined and maintained by the storage microparticles, and is not prone to significant migration during use or storage. The migration rate of Comparative Example 4 is significantly higher than that of Example 7, indicating that the direct spraying method easily leads to the free spreading and migration of the low-volatility dust-locking liquid on the fiber surface. The migration rate of Comparative Example 5 is also higher than that of Example 7, indicating that the moisture in the pores of the storage microparticles affects the entry of the low-volatility dust-locking liquid into the pores, resulting in an increase in the proportion of free liquid. The migration rate of Comparative Example 6 is 7.8%, indicating that the fixed component can help the liquid-carrying storage microparticles to adhere stably to the fiber skeleton and indirectly reduce the risk of dust-locking liquid migration.

[0080] Liquid storage particle shedding rate test: Each sample was placed in an airflow with a wind speed of 1.0 m / s and purged for 30 min, and the detached particles downstream of the sample were collected. The liquid storage particle shedding rate was calculated based on the change in the mass of liquid storage particles in the sample before and after purging, and the results are shown in Table 6.

[0081] Table 6

[0082] As shown in Table 6, the drop rates of the liquid-carrying microparticles in Examples 7-10 were all low, indicating that the liquid-carrying microparticles could be stably attached to the modified fiber skeleton by the fixation component. The drop rate of the liquid-carrying microparticles in Comparative Example 6 was significantly higher than that in Example 7, indicating that the fixation component could significantly improve the fixation stability of the liquid-carrying microparticles on the fiber skeleton; the drop rate of the liquid-carrying microparticles in Comparative Example 2 was higher than that in Example 7, indicating that the modified layer could improve the polarity and roughness of the fiber surface, providing anchoring points for the liquid-carrying microparticles; the drop rate of the liquid-carrying microparticles in Comparative Example 7 was also higher than that in Example 7, indicating that negative pressure assistance helps the dust-locking dispersion enter the fiber channels and deposit at fiber intersections or pore wall areas, thereby improving the stability of the dust-locking phase.

[0083] Pressure drop growth rate test after dust loading: Each sample was installed in a dust loading test device, and a standard dust aerosol was introduced at a test wind speed of 0.3 m / s to ensure all samples had the same dust load. The pressure drop before and after dust loading was measured, and the pressure drop growth rate was calculated using the following formula: Pressure drop growth rate (%) = (ΔP2 - ΔP1) / ΔP1 × 100% Where ΔP1 is the initial pressure drop and ΔP2 is the pressure drop after dust loading; The test results are shown in Table 7.

[0084] Table 7

[0085] As shown in Table 7, the pressure drop growth rate of Examples 7-10 after dust loading was lower than that of the comparative examples, indicating that the purification material of the present invention does not easily form a dense dust layer after capturing particulate matter, and maintains good air permeability. Comparative Example 4 had the highest pressure drop growth rate, indicating that direct spraying of low-volatility dust-locking liquid easily causes liquid spreading and local accumulation of particulate matter, causing the pores to shrink more quickly. Compared with Comparative Example 4, Example 7 had a higher particulate matter retention rate and a lower pressure drop growth rate, indicating that the present invention can avoid the problems of continuous liquid film and pore blockage caused by direct spraying by storing liquid particles to confine the low-volatility dust-locking liquid.

[0086] As shown in Tables 3-7, Examples 7-10 exhibit better overall performance. This invention enables the low-volatility dust-locking liquid to be confined, held, and stably fixed on the surface or pore wall region of the fiber skeleton, thereby improving the retention capacity after particulate matter capture, reducing the risk of particulate matter resuspension, and avoiding the problems of pore blockage and increased pressure drop caused by direct spreading of the low-volatility dust-locking liquid. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this invention; therefore, the scope of protection of this invention should be determined by the scope defined in the claims.

Claims

1. A method for preparing a purification material that reduces the concentration of particulate matter in ambient air, characterized in that, Includes the following steps: S100: Polyester fiber and cellulose fiber are mixed and then subjected to web laying and reinforcement treatments in sequence to obtain a fiber skeleton; S200. Apply the modified liquid to at least a portion of the surface of the fiber skeleton to obtain a modified fiber skeleton. S300. The dust-locking dispersion is atomized and sprayed onto the surface of the modified fiber skeleton, and then dried and shaped in sequence to obtain the purification material. The dustproof dispersion liquid has a liquid amount of 2-8 g / m 2 .

2. The preparation method according to claim 1, characterized in that, In step S300, the preparation method of the dust-locking dispersion includes the following steps: S301. Mix glycerin, PEG-400 and sorbitol aqueous solution to obtain a low-volatility dust-locking liquid; S302. After pre-drying the storage microparticles, add them to the low-volatility dust-locking liquid and stir to obtain liquid-carrying storage microparticles. S303. Add a fixed component to the liquid storage microparticles and mix to obtain the dust-locking dispersion.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the glycerol, the PEG-400, and the sorbitol aqueous solution is 1:(0.5~2):(0.2~1); and / or The mass ratio of the reservoir microparticles to the glycerol is (1.5~2):1; and / or The mass ratio of the fixed component to the glycerol is (4~10):

1.

4. The preparation method according to claim 2, characterized in that, The pre-drying treatment is performed at a temperature of 60-100℃ for a time of 30-120 minutes; and / or The stirring speed is 300~1000 rpm and the time is 20~60 min.

5. The preparation method according to claim 2, characterized in that, The particle size of the reservoir microparticles is 5~20μm; and / or The liquid storage particles include at least one or a combination of diatomaceous earth, porous silica, sepiolite, and attapulgite; and / or The fixed component includes at least one or a combination of aqueous polyurethane emulsion and acrylic emulsion.

6. The preparation method according to claim 1, characterized in that, In S300, The drying process is carried out at a temperature of 50-90°C for a time of 10-60 minutes; and / or The shaping process involves placing the object at 25-40°C and 40-70% relative humidity for 6-24 hours to achieve equilibrium.

7. The preparation method according to claim 1, characterized in that, In step S200, the modified liquid, by mass parts, comprises: Film-forming matrix 2-10 parts, inorganic filler 1-8 parts, dispersant 0.1-0.5 parts, deionized water 100 parts; The film-forming matrix includes chitosan or cationic starch; The inorganic filler includes at least one or a combination of diatomaceous earth, nano-silica and zeolite powder; The pH of the modified solution is 4~7.

5.

8. The method of claim 1, wherein, In step S200, coating at least a portion of the surface of the fiber skeleton with the modified liquid includes: The modified liquid is applied to at least a portion of the surface of the fiber skeleton by padding, and the roll-off rate is controlled to be 60-120%. or The modified liquid is sprayed on the surface of the fiber framework, and after spraying, it is dried at 50-80°C for 10-40 min, and the liquid uptake of the modified liquid is 5-20 g / m 2 .

9. The method of claim 1, wherein, Between S100 and S200, there is also: S110. Pre-treat the fiber skeleton; The pretreatment includes corona treatment, plasma treatment, weak alkali treatment, or deionized water washing and drying.

10. A purification material for reducing the concentration of particulate matter in ambient air, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.

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