Method and cutting device for the extraction of plastic micro-particles from a fabric

Abstract

The application provides a method for extracting plastic micro-particles in a fabric, comprising the following steps: embedding the fabric with an embedding liquid, freezing to solidification to obtain a solid to be cut; cutting the solid to be cut and collecting the solid flake obtained by cutting; centrifuging the solid flake after the solid flake is melted, and drying to obtain the plastic micro-particles. The extraction method can obtain plastic micro-particles with small size and high purity, which is beneficial to providing a technical basis for in-depth research on the pollution of plastic micro-particles to the ecological environment and the harm to biological health. The application further provides a cutting device for plastic micro-particles.

Description

Technical Field

[0001] This application relates to the field of material extraction technology, specifically to a method and cutting device for extracting plastic microparticles from fabrics. Background Technology

[0002] With the widespread use of plastics in human society, their pollution of the ecological environment and potential harm to organisms have become a research area of ​​great practical significance. Against this backdrop, microplastics, which can enter the ecological environment and be absorbed by organisms (e.g., plants, mammals) and affect their health, are a research subject worthy of focused attention. However, due to the limited availability of commercially available microplastics, and the fact that most commercially available microplastics are artificially synthesized with specific compositions and shapes, it is difficult to simulate microplastics formed naturally from the breakup of large pieces of plastic. Therefore, the extraction of microplastics is a necessary technique for researchers to conduct in-depth studies on the environmental problems caused by microplastics.

[0003] Early methods of obtaining plastic microparticles by cutting or cryogenically grinding plastic wires resulted in microparticles that were too large, typically exceeding 500 μm, making them unsuitable for studying the effects of plastic microparticles on small mammals. Current techniques involve binding neatly arranged nylon or other fibers with tape around a spool, embedding them in a glycosyl cryo-embedding agent, freezing them, and then sectioning them using a microtome to obtain plastic fibers / microparticles of 20 μm-50 μm. However, these extraction techniques still have several limitations, such as the still large size of the plastic microparticles, the inability to exclude the influence of tape and cryo-embedding agents on the sample, complex sample pretreatment, and the easy loss of plastic microparticles during the cutting process, which can pollute the surrounding environment.

[0004] Therefore, it is necessary to break through the limitations of existing technologies and provide a better method for extracting microplastics in order to improve the extraction quality and yield of microplastics. Summary of the Invention

[0005] In view of this, this application provides a method and cutting device for extracting microplastics from fabrics. The sample pretreatment for the microplastic extraction method is simple, and the microplastics obtained by the method are free of adhesive tape, cryogenic embedding agents, etc., thus eliminating the influence of external substances. Furthermore, the microplastics have different sizes and shapes, simulating microplastics formed naturally from large pieces of plastic breaking apart. The obtained microplastics contain smaller sizes ranging from 2μm to 20μm, which can meet the research needs on the effects of microplastics on small mammals and improve the extraction quality. The cutting device effectively reduces the loss of microplastics during the cutting process and the pollution to the surrounding environment, thereby increasing the yield of microplastics.

[0006] Specifically, in a first aspect, this application provides a method for extracting microplastics from a fabric, comprising the following steps:

[0007] The fabric was embedded with an embedding liquid and then frozen until solidified to obtain the solid to be cut.

[0008] The solid to be cut is cut, and the resulting solid slices are collected.

[0009] After the solid sheet melts, it is centrifuged and dried to obtain the plastic microparticles.

[0010] Optionally, the embedding liquid includes one or more of water, edible oil, honey, and drug solution.

[0011] Specifically, the process of cutting the solid to be cut involves cutting the solid into thin slices of a preset thickness, wherein the preset thickness is less than or equal to 1 μm.

[0012] Optionally, the temperature during the cutting process is between -50°C and -20°C.

[0013] The freezing temperature is lower than or equal to the temperature during the cutting process.

[0014] In this application, the size of the plastic microparticles is 2μm-200μm.

[0015] The method for cutting plastic microparticles from fabrics provided in the first aspect of this application is simple to operate, does not introduce foreign substances, and can obtain plastic microparticles of different sizes and shapes. The obtained plastic microparticles contain small sizes of 2μm-20μm, which can meet the research needs of the impact of plastic microparticles on small mammals and help to expand the research scope of plastic microparticles on ecological environment pollution and biological health hazards.

[0016] Secondly, this application provides a cutting device, including a slicer and a centrifuge tube. The slicer includes a slicing platform, and the centrifuge tube has a cut end at the tube opening, the edge of which is in contact with the slicing platform; or the tube wall near the tube opening of the centrifuge tube includes an inclined plane, the inclined plane being in contact with the slicing platform.

[0017] In this application, the slicer also includes a cutting blade disposed on the slicing platform, and the opening of the centrifuge tube covers the area where the cutting blade is located.

[0018] In this application, the slicer also includes a tray for holding the material to be cut, the tray being located below the cutting blade, and the angle α between the central axis of the centrifuge tube and the surface of the tray being 85°-120°.

[0019] In this application, the centrifuge tube has a threaded section at its opening, and the cutting depth of the centrifuge tube is less than the height of the threaded section at the opening of the centrifuge tube; or the vertical distance between the first end away from the opening and the second end located at the opening on the inclined plane of the centrifuge tube is less than the height of the threaded section at the opening of the centrifuge tube.

[0020] The cutting device provided in the second aspect of this application can effectively reduce the loss of microplastics during the cutting process, the pollution to the surrounding environment, and the harm to the cutting personnel, and is conducive to improving the yield of microplastics. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the extraction process of microplastic particles in an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of the cutting device according to an embodiment of this application;

[0023] Figure 3 This is a schematic diagram of the centrifuge tubes used in the embodiments of this application;

[0024] Figure 4 This is a schematic diagram of a centrifuge tube with a notch at one end, as described in one embodiment of this application.

[0025] Figure 5 This is a schematic diagram of a centrifuge tube with an inclined plane on the tube wall near the end of the tube in one embodiment of this application.

[0026] Figure 6 This is a schematic diagram of the solid to be cut in an embodiment of this application;

[0027] Figure 7 This is a microscopic image of the plastic microparticles extracted in Example 1 of this application;

[0028] Figure 8 This is a microscopic image of the plastic microparticles extracted in Example 2 of this application.

[0029] Figure 9 This is a microscopic image of the plastic microparticles extracted in Example 3 of this application;

[0030] Figure 10 This is a microscopic image of the plastic microparticles extracted in Comparative Example 1 of this application.

[0031] Figure 11 This is a microscopic image of the plastic microparticles extracted in Comparative Example 2 of this application.

[0032] Figure 12 This is a photograph of the plastic microparticles obtained after drying in Comparative Example 3 of this application;

[0033] Figure 13This is a photograph of the plastic microparticles extracted in Example 1 of this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0035] See Figure 1 This application provides a method for extracting plastic particles from fabrics, comprising the following steps:

[0036] S10. Embed the fabric with the embedding liquid, freeze until solidified, and obtain the solid to be cut;

[0037] S20. Cut the solid to be cut and collect the resulting solid slices;

[0038] S30. After the solid sheet melts, centrifuge and dry it to obtain the plastic microparticles.

[0039] In this embodiment, plastic fibers in fabrics are used as the source for extracting microplastics. That is, the desired microplastics are obtained by cutting the plastic fibers in the fabric. The applicability of this method is not limited by the spatial arrangement of the plastic fibers. In other words, the method provided in this embodiment overcomes the limitation that plastic fibers used for extracting microplastics must be regularly arranged. It can extract microplastics from various fabrics containing the desired plastic fibers, such as clothing fabrics and mask fabrics. Since it is not necessary to regularly arrange the plastic fibers by wrapping them around a spool, the method provided in this application helps reduce experimental costs. In one embodiment of this application, plastic fibers in the nonwoven fabric layer of a mask can be used as the source for extracting microplastics. This nonwoven fabric layer is made of melted polypropylene that is then drawn into a web, containing a large number of plastic fibers with an interlaced mesh structure.

[0040] See Figure 6In this embodiment, the pretreatment for extracting microplastics from the fabric includes embedding the fabric 601. Specifically, this can be done by cutting the fabric 601 into multiple pieces of the same or similar size and stacking them in the embedding container 602 for embedding, or by folding the fabric 601 multiple times and placing it in the embedding container 602 for embedding. Furthermore, the single-cutting amount of plastic fibers can be increased by controlling the ratio of the fabric volume to the embedding container volume, thereby increasing the yield of microplastics after a single cut. For example, the fabric volume in the embedding container can be controlled to be 2 / 3 or more of the embedding container volume. In specific embodiments, the fabric volume in the embedding container can be 2 / 3, 3 / 4, 4 / 5, 5 / 6, etc., of the embedding container volume. In one embodiment of this application, after the non-woven fabric layer of the mask is cut off, it is further cut into multiple pieces of non-woven fabric with a side length of about 1.8cm. The non-woven fabric pieces are then stacked to form a cube with a side length of about 1.8cm, and then placed into a cube embedding container with a side length of about 2cm for subsequent embedding.

[0041] Because plastics, once in the natural environment, can exist in various fluid media and flow with the fluid medium, during animal food ingestion, microplastics may enter the animal's body along with the fluid medium connected to the ingestion route, and then be absorbed by the animal's digestive system, harming the animal's health. Based on the different ingestion routes of microplastics by animals in the natural environment, in this embodiment, a fluid medium connected to the animal's final ingestion route can be selected as the embedding liquid 603 to replace traditional glycosyl cryo-embedding agents. This selection of the embedding liquid allows for a more realistic simulation of animal microplastic ingestion, improving the reliability of research on the harm of microplastics to animals; it also eliminates interference caused by residual cryo-embedding agents in the sample, ensuring the effectiveness of the experimental design. Depending on research needs, the embedding liquid 603 in this embodiment may include one or more of water, edible oil, honey, and drug solutions, but is not limited to these.

[0042] In this embodiment, the embedding liquid 603 is added to the embedding container 602 containing the fabric 601 until the fabric 601 is completely covered. After squeezing out the air between the fabrics 601, the embedding container 602 is then filled with the embedding liquid 603. This embodiment of the application, through the above-mentioned operation of removing air between the fabrics, allows the embedding liquid to more fully embed the fabric, thereby avoiding the formation of a hollow structure in the solid to be cut due to the presence of air after freezing and solidification. This prevents uneven stress on the solid to be cut during the cutting process, thus affecting the cutting effect. In this embodiment of the application, the solid to be cut is obtained by freezing the fabric and the embedding liquid at a certain temperature for a certain time. Specifically, the embedding container containing the fabric can be placed in a refrigerator at a temperature lower than or equal to -20°C until solidification, for example, -20°C, -40°C, -50°C, -60°C, -70°C, -80°C, etc. This process typically takes 10 minutes. To improve the solidification effect, the solidified solid to be cut can be frozen for an additional period of time, such as 5 minutes, 10 minutes, 15 minutes, or 20 minutes. In one embodiment of this application, after embedding, the embedding container is placed in a freezer at -80°C and frozen for 10 minutes until solidification, and then frozen for another 10 minutes to obtain the solid to be cut.

[0043] In this embodiment, the solid to be cut is placed on the tray of a slicer for cutting. Because the plastic fibers in the fabric form an interwoven mesh structure on the fabric surface, the plastic microparticles obtained by cutting along directions parallel to and perpendicular to the fabric surface have different size distribution characteristics. Specifically, cutting along a direction parallel to the fabric surface is equivalent to cutting along the length of the plastic fibers, resulting in plastic microparticles with a smaller size distribution range and a larger average size. Cutting along a direction perpendicular to the fabric surface is equivalent to cutting along different directions of the plastic fibers, resulting in plastic microparticles with an even larger size distribution range and a smaller average size. These different directions include directions parallel to the length of the plastic fibers, directions perpendicular to the length of the plastic fibers, and directions forming other angles with the length of the plastic fibers. Cutting along a direction perpendicular to the length of the plastic fibers yields smaller-sized plastic microparticles, cutting along a direction parallel to the length of the plastic fibers yields larger-sized plastic microparticles, and cutting along directions forming other angles with the length of the plastic fibers yields plastic microparticles with sizes between smaller and larger sizes. This embodiment of the application adjusts the placement direction of the solid to be cut, so that the cutting direction of the cutting blade is perpendicular to the non-woven fabric surface. This allows the cutting blade to cut in different directions of the plastic fibers, resulting in a wider distribution of plastic microparticles across a larger size range. This facilitates a better simulation of the distribution of plastic microparticles of various sizes in the environment. After adjusting the placement direction, ultrapure water or embedding liquid is injected into the contact edge between the solid to be cut and the tray, connecting them through the ultrapure water or embedding liquid. Once the ultrapure water or embedding liquid freezes, the solid to be cut is firmly fixed on the tray, facilitating subsequent cutting.

[0044] In this embodiment, by controlling the temperature of the slicer chamber during the cutting process to -50°C to -20°C, the solid to be cut is kept in a better cuttable state. In this cuttable state, the plastic fibers in the fabric can have greater rigidity and are less prone to bending and deformation during cutting, which is beneficial for obtaining smaller plastic microparticles. Specifically, the temperature of the slicer chamber during the cutting process can be -50°C, -45°C, -40°C, -35°C, -30°C, -25°C, -20°C, etc. Since the temperature of the solid to be cut may rise during the transfer to the slicer after freezing, causing the temperature of the solid to be cut to be higher than the suitable cutting temperature, the fibers in the fabric to be cut will bend and deform during the cutting process, thus affecting the cutting effect of the plastic fibers. This application avoids the adverse effects of the increased temperature of the solid to be cut on the cutting effect by controlling the freezing temperature of the solid to be cut in the refrigerator to be lower than or equal to the temperature during the cutting process. For example, in one embodiment of this application, the freezing temperature of the solid to be cut in the refrigerator can be set to -80°C, and the temperature during the cutting process can be set to -40°C.

[0045] In this embodiment, plastic microparticles within the desired size range can be obtained by cutting the solid to be cut into thin slices of a preset thickness. The preset thickness can be less than or equal to 1 μm, specifically 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, etc. In one embodiment of this application, cutting the solid to be cut to a preset thickness of 0.5 μm results in small plastic microparticles (2 μm-20 μm) that can be absorbed by the mammalian digestive system, facilitating a more accurate study of the harmful effects of plastic microparticles on mammals. In this embodiment of the application, the size range of the plastic microparticles obtained by the above cutting method is 2μm-200μm, specifically 2μm, 3μm, 5μm, 10μm, 15μm, 20μm, 25μm, 50μm, 75μm, 100μm, 125μm, 150μm, 175μm, 200μm, etc.

[0046] In this embodiment, the thin solid slices obtained from cutting are prone to breakage due to their thinness, falling into the centrifuge tube as irregular fragments or debris. This application addresses this by directly collecting the cut solid slices in the centrifuge tube and tightening the cap. This helps prevent the solid slices from splashing around inside the slicer chamber, causing loss of microplastics, contamination of the slicer chamber, and harm to the operator. Furthermore, it confines the falling space of the solid slices within the centrifuge tube, reducing the contact area between the solid slices and the slicing platform, thereby reducing microplastic residue and contamination on the slicing platform.

[0047] In this embodiment, after tightening the centrifuge tube cap, centrifugation is performed after the solid flakes inside the centrifuge tube have melted, separating the plastic microparticles from the encapsulating liquid. The separated plastic microparticles accumulate at the bottom of the centrifuge tube, while the encapsulating liquid accumulates at the top. After centrifugation, the centrifuge tube cap is loosened for drying. This process helps ensure gas flow while isolating the solid plastic microparticles inside the centrifuge tube, preventing them from flowing with the outside environment. As a result, the encapsulating liquid inside the centrifuge tube is removed through drying, while the plastic microparticles are almost completely removed, thus increasing the yield of plastic microparticles.

[0048] See Figure 13The dried product obtained is a mixture of plastic microparticles of different sizes. In this embodiment, the small-sized plastic microparticles with a diameter of 2μm-20μm account for 0.5%-2% of the total extracted plastic microparticles by mass, specifically 0.5%, 1%, 1.5%, 2%, etc. This embodiment can separate and screen the dried plastic microparticles to obtain plastic microparticles of 2μm-20μm for research on the harmful effects of plastic microparticles on mammals. Other sizes of plastic microparticles can also be separated and screened according to research needs. In this application, the separation methods include electrostatic adsorption separation and centrifugal separation. Furthermore, the plastic microparticles obtained by the above extraction method can be stored in a sealed container without the need for water storage. The plastic microparticles can be used immediately after drying or after sealed storage without further pretreatment, which improves experimental efficiency.

[0049] The method for extracting microplastics from fabrics provided in this application is simple to operate, does not introduce any external substances, and can obtain microplastics of different sizes and shapes. The obtained microplastics contain smaller sizes of 2μm-20μm, which can meet the research needs of the impact of microplastics on small mammals and help to expand the research scope of microplastics on ecological environment pollution and biological health hazards.

[0050] See Figures 2-5 This application also provides a slicing device 100, including a slicer and a centrifuge tube 10b. The slicer includes a slicing platform 20, and the tube end of the centrifuge tube 10b has a cut 10b-1, the edge of which is in contact with the slicing platform 20; or the tube wall near the tube end of the centrifuge tube 10b includes an inclined plane 10b-2, which is in contact with the slicing platform 20.

[0051] The aforementioned slicer also includes a tray 30 for holding the material to be sliced ​​and a cutting blade 40 mounted on the slicing platform. The centrifuge tube 10b is fixed to the slicing platform 20 by freezing water 50 or frozen embedding liquid 50, and the solid to be sliced ​​60 is fixed to the tray 30 by the same method. During the slicing process, the tray 30 reciprocates along the cutting direction, continuously slicing the material 60 according to a set cutting thickness. The solid flakes cut by the cutting blade 40 fall off and are collected inside the centrifuge tube 10b.

[0052] In this embodiment, by setting a centrifuge tube 10b on the slicing platform 20, the cut solid slices can be directly collected in the centrifuge tube 10b. This helps to avoid the loss of plastic particles caused by the solid slices splashing around in the slicer chamber, reduces pollution of the slicer chamber, and lowers the risk of operators inhaling plastic particles. Furthermore, it reduces the contact area between the solid slices and the slicing platform, thereby reducing the residue and contamination of plastic particles on the slicing platform. In one embodiment, a centrifuge tube with a notch at the end is used to collect plastic particles, controlling the contact area between the plastic particles and the slicing platform within the area enclosed by the edges of the notch and the slicing platform. In another embodiment, to further reduce the contact between plastic particles and the slicing platform, a specially designed centrifuge tube with an inclined plane on the wall near the notch end is used to collect plastic particles, allowing the plastic particles to fall directly onto the inclined plane, thus avoiding direct contact between the plastic particles and the slicing platform.

[0053] In this embodiment, the shape and position of the cut 10b-1 of the centrifuge tube 10b, or the position of the inclined plane 10b-2 of the centrifuge tube 10b, can be designed and adjusted according to actual needs. By designing the shape of the cut 10b-1, it can be made to fit flush with the slicing platform, thereby preventing solid flakes from scattering onto the slicing platform 20 outside the centrifuge tube 10b, which helps reduce the loss of plastic particles and improve the yield of plastic particles. By adjusting the position of the cut 10b-1 or the inclined plane 10b-2, on the one hand, the opening of the centrifuge tube 10b can cover the area where the cutting blade 40 is located; that is, the projection of the centrifuge tube wall on the cutting blade can completely cover the cutting blade 40, thus ensuring that the cut solid flakes can fall into the centrifuge tube. On the other hand, the centrifuge tube 10b can have a suitable degree of inclination, which, without hindering normal cutting, better plays the role of blocking solid flakes from splashing, further reducing the loss of plastic particles and improving the yield of plastic particles. The aforementioned degree of tilt can be represented by the angle α between the central axis L of the centrifuge tube 10b and the surface of the tray 30. If the angle α is too small, the opening of the centrifuge tube 10b will come into contact with the solid to be cut, hindering the movement of the solid along the cutting direction during the cutting process. If the angle α is too large, the resulting fragmented or shard-like slices may splash out of the centrifuge tube and fall into the slicer chamber, causing contamination. See also Figures 3-5In this embodiment of the application, by adjusting the ratio of the depth L1 of the cut 10b-1 to the width L2 of the cut 10b-1, or by adjusting the ratio of the vertical distance L1 between the first end A away from the tube opening and the second end B located at the tube opening on the inclined plane 10b-2 and the projection width L2 of the inclined plane 10b-1 in the tube opening direction, the included angle α can be controlled within the range of 85°-120°, so that the centrifuge tube has a more suitable degree of inclination. The included angle α can specifically be 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, etc.

[0054] In this embodiment, the centrifuge tube 10b is fixed to the slicing platform 20 by freezing water 50 or frozen embedding liquid 50, meaning the centrifuge tube 10b is a detachable structure. Specifically, before cutting begins, the centrifuge tube 10b is placed upside down on the slicing platform 20 near the cutting blade 40, so that the edge of the cut 10b-1 or the inclined plane 10b-2 is in contact with the slicing platform 20. Then, ultrapure water or embedding liquid is injected into the contact edge between the centrifuge tube 10b and the slicing platform 20, connecting the centrifuge tube 10b and the slicing platform 20 through the ultrapure water or embedding liquid. After the ultrapure water or embedding liquid freezes, the centrifuge tube 10b is firmly fixed to the slicing platform 20. The centrifuge tube 10b serves both as a barrier during the cutting process and as a collection and storage unit after cutting. Specifically, during the cutting process, the centrifuge tube can be used to prevent solid slices from splashing, thereby avoiding contamination caused by solid slices scattering inside the slicer chamber. After cutting, the centrifuge tubes are capped and can be used to collect and store solid flakes.

[0055] Since the cut solid sheet needs to be dried in the centrifuge tube 10b, and the centrifuge tube cap needs to be loosened during the drying process to ensure that the embedded liquid can evaporate while the plastic particles are isolated inside the centrifuge tube, in this embodiment of the application, the centrifuge tube 10b has a threaded section at the opening, and the cut depth L1 of the centrifuge tube 10b is less than the threaded section depth L3 at the opening of the centrifuge tube 10b, or the vertical distance L1 between the first end away from the opening and the second end located at the opening on the inclined plane 10b-2 of the centrifuge tube is less than the threaded section depth L3 at the opening of the centrifuge tube 10b. That is, the cap 10a of the centrifuge tube can completely cover the cut 10b-1 or the inclined plane 10b-2 of the centrifuge tube 10b.

[0056] The aforementioned detachable centrifuge tubes can be disposable coarse plastic centrifuge tubes, which can be used throughout the entire process of microplastic extraction. This helps reduce the loss of microplastics due to sample transfer in different operation steps, and can also effectively avoid cross-contamination between different samples due to unclean centrifuge tubes.

[0057] In this embodiment, the cutting device described above can also be applied to cutting other materials, including but not limited to materials that are corrosive to metals. Depending on the properties of the material being cut, the cutting blade and slicing platform can be replaced with other suitable materials such as ceramics.

[0058] The cutting device provided in this application embodiment can effectively reduce the loss of plastic microparticles during the cutting process and the pollution to the surrounding environment, which is conducive to improving the yield of plastic microparticles.

[0059] The implementation scheme of this application will be further explained below with several case studies.

[0060] Example 1

[0061] A method for extracting microplastics from a face mask includes the following steps:

[0062] (1) Processing plastic fibers. Cut off the non-woven fabric layer of the mask made of polypropylene meltblown fabric, then cut the non-woven fabric layer of the mask into non-woven fabric pieces with a side length of about 1.8 cm, stack the non-woven fabric pieces and put them into a cube-shaped embedding container with a side length of 2 cm;

[0063] (2) Embedding. Fill the cube-shaped embedding container containing the non-woven fabric with ultrapure water, squeeze out the air between the non-woven fabric pieces, and fill the embedding container with ultrapure water again; place the container in a freezer at -80°C for 10 minutes until solidified, and continue to freeze at -80°C for 10 minutes to obtain the solid to be cut.

[0064] (3) Slicing. Place the frozen solid to be sliced ​​into a slicer and freeze it on a tray with ultrapure water. Set the cutting thickness to 0.5 μm and cut the solid to be sliced ​​at a machine temperature of -40℃. While cutting, collect the sliced ​​solid slices in a centrifuge tube. After cutting, tighten the centrifuge tube cap to obtain the plastic microparticles to be extracted.

[0065] (4) Extraction of microplastics. After the solid flakes in the centrifuge tube melt, centrifuge the tube. After centrifugation, loosen the centrifuge tube and dry it in an oven at 45℃-60℃. The remaining substance in the centrifuge tube after drying is the microplastic.

[0066] Example 2

[0067] A method for extracting microplastics from a face mask, which differs from Example 1 only in that: in step (3), the cutting thickness is set to 1 μm.

[0068] Example 3

[0069] A method for extracting microplastics from a mask, which differs from Example 1 only in that: in step (3), the solid to be cut is cut at a machine room temperature of -20°C.

[0070] To highlight the beneficial effects of this application, the following comparative examples are provided:

[0071] Comparative Example 1

[0072] A method for extracting microplastics from a face mask, which differs from Example 1 only in that: in step (3), the cutting thickness is set to 2 μm.

[0073] Comparative Example 2

[0074] A method for extracting microplastics from a mask, which differs from Example 1 only in that: in step (3), the solid to be cut is cut at a machine room temperature of -10°C.

[0075] Comparative Example 3

[0076] A method for extracting microplastics from a face mask differs from Example 1 only in that, in step (2), an optimal cutting temperature compound is used to embed the nonwoven fabric. The optimal cutting temperature compound is a water-soluble mixture of polyethylene glycol and polyvinyl alcohol.

[0077] To verify the beneficial effects of the technical solutions in the embodiments of this application, the plastic microparticles obtained in Examples 1-3 and Comparative Examples 1-2 were placed under a microscope to observe the size range of the plastic microparticles. The results are as follows: Figures 7-11 And as shown in Table 1 below. In addition, the plastic microparticles obtained in Comparative Example 3 were observed using the naked-eye observation method, and the results are as follows: Figure 12 As shown.

[0078] Table 1

[0079] Plastic particle size range (μm) Example 1 2-200 Example 2 2-550 Example 3 2-300 Comparative Example 1 3-800 Comparative Example 2 8-900

[0080] Depend on Figures 7-11 As shown in Table 1, the plastic microparticles obtained in Examples 1-3 of this application exhibit different sizes and shapes within observation ranges of 200 μm, 100 μm, 50 μm, and 10 μm, which helps to better simulate plastic microparticles formed from the breakage of large pieces of plastic under natural conditions. Furthermore, the plastic microparticles obtained in Examples 1, 2, and 3 have size ranges of 2 μm-200 μm, 2 μm-550 μm, and 2 μm-300 μm, respectively, and all three examples contain smaller plastic microparticles of 2 μm-20 μm, with the smallest size reaching 2 μm-3 μm. This meets the research needs regarding the impact of plastic microparticles on small mammals and helps to expand the research scope on the environmental pollution and biological health hazards of plastic microparticles.

[0081] Compared to Examples 1-3, Comparative Example 1 had an excessively large cutting thickness, resulting in larger extracted plastic microparticles with a minimum size that was difficult to achieve (2μm-3μm). Therefore, it was difficult to meet the research requirements regarding the effects of plastic microparticles on small mammals. In Comparative Example 2, the slicer chamber temperature was high during the cutting process, causing the plastic fibers to bend and deform, resulting in larger extracted plastic microparticles with a minimum size that could not reach 2μm-3μm. Therefore, it also failed to meet the research requirements regarding the effects of plastic microparticles on small mammals.

[0082] In Comparative Example 3, a cryo-section embedding agent was used to embed the nonwoven fabric. Figure 12 It can be seen that solid residue b of cryosection embedding agent exists around the dried plastic microparticle a. This solid residue b is not easy to separate from the plastic microparticle a, resulting in low purity of the prepared plastic microparticle sample, which is difficult to apply in refined research.

Claims

1. A method for extracting microplastics from fabrics, characterized in that, Includes the following steps: The fabric is embedded in an embedding liquid, the air between the fabric is squeezed out, and then frozen until solidified to obtain the solid to be cut. The embedding liquid includes water, and the freezing temperature is lower than or equal to the temperature during the cutting process. The solid to be cut is cut into thin slices according to a preset thickness, the preset thickness being less than or equal to 1 μm, the temperature during the cutting process is -50℃ to -20℃, and the cut solid slices are collected. After the solid sheet melts, it is centrifuged and dried to obtain the plastic microparticles, the minimum size of which is 2μm-3μm. The cutting device used includes a slicer and a centrifuge tube. The slicer includes a slicing platform. The centrifuge tube is placed upside down on the slicing platform. The end of the centrifuge tube has a cut. The edge of the cut is in contact with the slicing platform. The slicer also includes a tray for holding the material to be cut, the tray being located below the cutting blade, and the angle α between the central axis of the centrifuge tube and the surface of the tray being 85°-120°.

2. The method for extracting plastic microparticles from fabrics as described in claim 1, characterized in that, The size of the plastic microparticles is 2μm-200μm.

3. The method for extracting plastic microparticles from fabrics as described in claim 1, characterized in that, The plastic microparticles with a size of 2μm-20μm account for 0.5%-2% of the total mass of the plastic microparticles.

4. The method for extracting plastic microparticles from fabrics as described in claim 1, characterized in that, The slicer also includes a cutting blade disposed on the slicing platform, and the opening of the centrifuge tube covers the area where the cutting blade is located.

5. The method for extracting plastic microparticles from fabrics as described in claim 1, characterized in that, The centrifuge tube has a threaded section at its opening, and the cutting depth of the centrifuge tube is less than the height of the threaded section at the opening of the centrifuge tube. Alternatively, the vertical distance between the first end of the centrifuge tube away from the tube opening and the second end located at the tube opening on the inclined plane of the centrifuge tube is less than the height of the threaded section of the centrifuge tube opening.

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