Microscopic determination method for fiber microplastics in textile aqueous solution

Abstract

The invention discloses a microscopic determination method for fiber micro-plastics in a textile aqueous solution, and relates to the technical field of environmental pollutant detection.The method comprises the steps that a water sample is collected; preparing a Nile red staining solution; adding the prepared nile red staining solution into a water sample and carrying out fluorescent staining on the water sample; filtering the water sample subjected to fluorescence dyeing by using a trace glass suction filtration device with a glass fiber filter membrane; washing the glass fiber filter membrane with an acetone solution, and washing the glass fiber filter membrane with third-stage water for multiple times; taking down the washed glass fiber filter membrane, and drying the glass fiber filter membrane in a vacuum oven; and placing the dried glass fiber filter membrane on a microscope objective table, observing fluorescent substances by using a fluorescence microscope, measuring the size and counting. The method has the effects of effectively eliminating the interference of background fluorescence and non-fiber micro-plastics, greatly reducing the omission ratio of the fiber micro-plastics, reducing the determination cost, not needing large instruments, being simple to operate and less in time consumption, and effectively improving the determination efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of textile pollutant detection, and in particular to a method for microscopic determination of fiber microplastics in a textile aqueous solution. Background Art

[0002] Plastic products are widely used worldwide due to their stability, strong plasticity, low thermal conductivity, high strength-to-weight ratio, and excellent durability. From industry, agriculture, construction, to household items, plastic products are present in every aspect of human life. Since mass production began in the 1950s, production has increased from 5 million tons to 322 million tons in 2016. According to a 2019 report released by Plastics Europe, global annual plastic production reached 359 million tons in 2018, 60% of which was discarded into the environment. It is estimated that by 2050, the amount of plastic produced on Earth will reach 30 billion tons. While this convenient use has also created a host of new problems. The term "microplastics" was first coined in 2004 by Thompson et al., who demonstrated the presence of fine plastic pollution in the environment. Microplastics are generally considered to be plastic particles, fibers, or fragments smaller than 5 mm in size. Microplastics primarily come from two sources: secondary microplastics and primary microplastics. Secondary microplastics are tiny particles and fragments of plastic discarded into the environment. Due to their resistance to degradation, they weather under the influence of water, light, mechanical wear, and biodegradation. Primary microplastics are microplastic products produced based on actual needs, such as cosmetics, toothpaste, and daily care products. Furthermore, researchers have discovered that washing machine wastewater contains large amounts of microplastic fibers. Microplastics have relatively stable physical and chemical properties, can be stored for long periods of time, and are difficult to completely degrade in the environment. In 2014, the United Nations Environment Programme (UNEP) listed them as one of the top ten emerging pollutants.

[0003] In recent years, with increasing awareness of microplastics, research on their presence in the environment has grown. This research has expanded from the ocean to freshwater, wetlands, and the organisms that inhabit them. By analyzing their bioaccumulation and transmission through the food chain, researchers are attempting to deduce the potential harm microplastics may pose to human health. In recent years, some researchers have suggested that fibers released from laundry may be a significant source of microplastics in aquatic environments, estimating that an average 6 kg wash load of textile fabric can release over 700,000 fibers.

[0004] The current relevant domestic standards for the determination of microplastics include: DB37 / T 4323-2021 "Technical Specifications for Monitoring Microplastics in Marine Aquaculture Areas" and DB21 / T2751-2017 "Determination of Microplastics in Seawater by Fourier Transform Microscopic Infrared Spectroscopy." Both methods use a stereomicroscope followed by a Fourier Transform Infrared spectrometer to determine the material of the microplastic particles. This method is time-consuming and requires a large infrared spectrometer, making it complex to operate and unable to meet the needs of rapid detection.

[0005] The relevant international standard currently is ISO / DIS 4484-2-2021(E) Textiles and textile products - Microplastics from textile sources - Part 2: Qualitative and quantitative evaluation of microplastics. This standard uses optical microscopy followed by Fourier transform infrared spectrometry and Raman spectroscopy for qualitative analysis of microplastics shed from textiles. This method requires two large instruments, a Fourier transform infrared spectrometer and a Raman spectrometer, and requires experienced professionals. Sample preparation is also complex and time-consuming. When using optical microscopy, accurate counting of light-colored microplastics can be difficult, leading to missed detections.

[0006] For example, an invention patent with patent publication number CN 109253907 A discloses a method for rapidly assisting the detection of microplastics in aquatic samples using Nile red staining. Nile red, a biological stain formulated with acetone, can stain hydrophobic microplastics in aquatic environments, producing a strong fluorescent effect under a fluorescence microscope. Fluorescence microscopy allows for rapid identification, counting, and sizing of stained substances. However, the measurement method provided by this technical solution has the following disadvantages: 1. It stains the filter membrane black and fails to eliminate background fluorescence interference, which interferes with the determination of microplastics; 2. Glue is required to fix the fibrous microplastics during operation, which is cumbersome; and 3. The filter membrane is an organic filter membrane, which is expensive.

[0007] For example, patent number CN 115753720 A discloses a quantitative detection method for microplastics by fluorescent staining based on Nile red dye. The detection method disclosed in this technical solution aims to eliminate the interference of other substances in the pollutant sample, and also cannot solve the problem of eliminating background fluorescence interference.

[0008] In addition, in the determination of fiber microplastics in the field of textile wastewater, we know that in addition to fiber microplastics, textile wastewater also contains other fibers such as cotton, viscose, flax, sheep wool, mulberry silk, polyacrylonitrile fiber, etc. These other fibers will interfere with the determination of fiber microplastics, resulting in inaccurate fiber microplastic counting. Summary of the Invention

[0009] The purpose of the present invention is to address the shortcomings of the prior art and propose a microscopic determination method for fiber microplastics in textile aqueous solutions. The aqueous solution or fiber microplastics that can be extracted into the aqueous solution is taken as the research object, and a method for determining fiber microplastics is obtained by coloring with fluorescent dyes and testing the fluorescence intensity.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A method for microscopic determination of fiber microplastics in a textile aqueous solution comprises the following steps:

[0012] S100, collecting surface wastewater from the environment into a water sampler, and stirring to obtain a uniform water sample;

[0013] S200, adding a biological colorant Nile red to an acetone solution to prepare a Nile red staining solution;

[0014] S300, pouring the uniform water sample into a beaker, and adding the prepared Nile red staining solution to perform fluorescent staining on the water sample;

[0015] S400, after standing for a period of time, filtering the fluorescently stained water sample using a micro-glass filtration device with a glass fiber filter membrane;

[0016] S500, flushing the sand core filter device on the suction filtration device with an acetone solution, and then flushing it multiple times with tertiary water;

[0017] S600, removing the washed glass fiber filter membrane and placing it in a vacuum oven for drying;

[0018] S700, placing the dried glass fiber filter membrane on a microscope stage, observing the fluorescent substance using a fluorescence microscope at a wavelength of 450-490 nm and a magnification of 4X or 10X, and measuring the size and counting.

[0019] Furthermore, the concentration of the Nile red staining solution prepared in S200 is 180-220 ug / ml.

[0020] Furthermore, in the S300, Nile red fluorescent dye is added at 1-3 ug / ml.

[0021] Furthermore, the step S400 is allowed to stand for 1-4 hours.

[0022] Furthermore, the amount of the S500 acetone solution is 8-15 ml.

[0023] Furthermore, the drying time in S600 is 1-4 hours.

[0024] Furthermore, the measurement stroke in S700 is: measurement starts from a corner of the glass fiber filter membrane, counting all fibers in a field of view, and repeated counting is not allowed. After measuring a field of view, move to an adjacent field of view in a direction parallel to the filter membrane to continue measuring, and continue to move the field of view in this direction to measure until one side of the filter membrane, and then move a field of view in a direction perpendicular to this direction, and then move in the opposite direction to measure back to the initial side, and measure in this way along a bow-shaped route until the entire glass fiber filter membrane is measured.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention provides a method for determining fiber microplastics, which is applied to the field of textile wastewater and can effectively eliminate the interference of fibers other than fiber microplastics in textile wastewater. At the same time, the method of combining glass fiber filter membrane with acetone washing for determination can not only eliminate the interference of background fluorescence, realize the quantitative determination of fiber microplastics, and greatly reduce the missed detection rate, but also use glass fiber filter membrane for filtration, which can ensure that the fiber microplastics show a good fluorescence effect, and the glass fiber filter membrane is low in price, which can reduce the determination cost of fiber microplastics;

[0027] (2) The determination method provided by the present invention does not require the use of large instruments such as Fourier transform infrared spectrometers and Raman spectrometers, is simple to operate, takes less time, and helps to improve detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram showing the measurement results of Test Example 1 of the present invention;

[0029] Figure 2 This is a diagram showing the measurement results of Test Example 2 of the present invention;

[0030] Figure 3 Graph showing the measurement results using glass fiber filter paper in Test Example 3 of the present invention;

[0031] Figure 4 This is a graph showing the measurement results using a nitrocellulose filter membrane in Test Example 3 of the present invention;

[0032] Figure 5 This is a graph showing the measurement results using aluminum oxide filter paper in Test Example 3 of the present invention;

[0033] Figure 6This is a diagram of the observation results under a fluorescence microscope in Example 1 of the present invention (at one viewing angle);

[0034] Figure 7 This is a diagram of the observation results under a fluorescence microscope in Example 1 of the present invention (from another viewing angle);

[0035] Figure 8 This is a diagram showing the results of observation under a fluorescence microscope in Experimental Example 4 of the present invention;

[0036] Figure 9 This is a diagram showing the results of observation under a fluorescence microscope in Example 2 of the present invention;

[0037] Figure 10 This is a diagram showing the results of observation under a fluorescence microscope in Experimental Example 5 of the present invention. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0039] The examples given in this application use the washing wastewater of black plush fabric blended with black cotton and polyester fibers and the washing wastewater of tops blended with viscose and nylon fibers as wastewater samples to determine fiber microplastics. The wastewater samples are not limited to these, but can also be other textile aqueous solutions, such as the washing wastewater of mats blended with polypropylene fibers and linen fibers. It should be pointed out that the choice of wastewater samples is diverse and can be selected according to actual needs.

[0040] The implementation principle of the embodiment of the present application is: taking the above-mentioned textile wastewater, using Nile red fluorescent dye to color the fiber microplastics after filtering the wastewater, and then coloring with the fluorescent dye and filtering it to a glass fiber filter membrane, rinsing the glass fiber filter membrane with a small amount of acetone solution to eliminate the background fluorescence of the Nile red dye on the glass fiber filter membrane and at the same time eliminate the interference of non-fiber microplastics in the textile wastewater, and then using a fluorescence microscope to observe the morphology and size of the colored fiber microplastics and count them to achieve quantitative detection results.

[0041] Example 1

[0042] This embodiment provides a method for microscopic determination of fiber microplastics in a textile aqueous solution, wherein the textile aqueous solution is wastewater from washing black plush fabric blended with black cotton and polyester fibers, and comprises the following steps:

[0043] S100. Use a water sampler to collect 2 L of black cotton and polyester blended black plush fabric washing wastewater and stir to obtain a uniform water sample. Simultaneously collect parallel samples. For specific methods, refer to GB 17378.3 Marine Monitoring Specifications, Part 3, Sample Collection, and the sampler collection section stored during transportation. Detailed description is omitted here.

[0044] S200, adding the biological colorant Nile red to the acetone solution to prepare a Nile red staining solution with a concentration of 200 μg / ml;

[0045] S300, pour the uniform water sample into a beaker, and add 2 ml of the prepared Nile red staining solution to perform fluorescent staining on the water sample;

[0046] S400, let it stand for 2 hours, and filter the fluorescently stained water sample using a micro-glass filtration device with a glass fiber filter membrane;

[0047] S500, rinse the sand core filter on the filtration device with 10ml acetone solution, and then rinse with tertiary water 3-5 times;

[0048] S600, remove the glass fiber filter membrane and place it in a vacuum oven to dry for 2 hours;

[0049] S700. Place the dried glass fiber filter membrane on the microscope stage, and use a fluorescence microscope to observe the fluorescent substance at a wavelength of 450-490 nm and a magnification of 10X to measure the size and count.

[0050] The measurement stroke is: measurement starts from one corner of the glass fiber filter membrane, counting all fibers in a field of view, and repeated counting is not allowed. After measuring a field of view, move to the adjacent field of view in a direction parallel to the filter membrane to continue measuring, and continue to move the field of view in this direction to measure until one side of the filter membrane, and then move one field of view in a direction perpendicular to this direction, and then move in the opposite direction to measure back to the initial side, and measure in this way along a bow-shaped route until the entire glass fiber filter membrane is measured.

[0051] Example 2

[0052] This embodiment provides a method for microscopically determining fiber microplastics in a textile aqueous solution, wherein the textile aqueous solution is wastewater from washing a garment blended with viscose and nylon fibers, and comprises the following steps:

[0053] S100. Use a water sampler to collect 5 L of wastewater from washing a viscose-nylon blended top and stir to obtain a uniform water sample. Simultaneously, collect parallel samples. For specific methods, refer to Part 3 of GB 17378.3 Marine Monitoring Specifications, Sample Collection and Storage, and the sampler collection section during transportation is omitted here for details.

[0054] S200, adding the biological colorant Nile red to the acetone solution to prepare a Nile red staining solution with a concentration of 200 μg / ml;

[0055] S300, pour the uniform water sample into a beaker, and add 5 ml of the prepared Nile red staining solution to perform fluorescent staining on the water sample;

[0056] S400, let it stand for 2 hours, and filter the fluorescently stained water sample using a micro-glass filtration device with a glass fiber filter membrane;

[0057] S500, rinse the sand core filter on the filtration device with 10ml acetone solution, and then rinse with tertiary water 3-5 times;

[0058] S600, remove the glass fiber filter membrane and place it in a vacuum oven to dry for 2 hours;

[0059] S700. Place the dried glass fiber filter membrane on the microscope stage, and use a fluorescence microscope to observe the fluorescent substance at a wavelength of 450-490 nm and a magnification of 10X to measure the size and count.

[0060] The measurement stroke is: measurement starts from one corner of the glass fiber filter membrane, counting all fibers in a field of view, and repeated counting is not allowed. After measuring a field of view, move to the adjacent field of view in a direction parallel to the filter membrane to continue measuring, and continue to move the field of view in this direction to measure until one side of the filter membrane, and then move one field of view in a direction perpendicular to this direction, and then move in the opposite direction to measure back to the initial side, and measure in this way along a bow-shaped route until the entire glass fiber filter membrane is measured.

[0061] Test Example 1

[0062] In addition to difficult-to-degrade microplastic fibers such as polyester fibers, polyamide fibers, polyethylene fibers, polypropylene fibers, etc., textile aqueous solutions also include other degradable fibers such as cotton, viscose, linen, sheep wool, mulberry silk, polyacrylonitrile fibers, etc. These fibers are mixed in textile aqueous solutions and will interfere with the determination of fiber microplastics.

[0063] Based on this, the microscopic determination method for fiber microplastics in aqueous textile solutions, as provided in this application, was used to measure single fiber microplastics and single fibers. The single fiber microplastics measured included polyester fibers, polyamide fibers, polyethylene fibers, and polypropylene fibers, while the single fibers measured included cotton, viscose, linen, sheep wool, mulberry silk, polyacrylonitrile fibers, acetate fibers, and triacetate fibers.

[0064] Polyester fiber, polyamide fiber, polyethylene fiber, polypropylene fiber, cotton, viscose fiber, flax, sheep wool, mulberry silk, polyacrylonitrile fiber, acetate fiber, and triacetate fiber were mixed with water to obtain several test water samples. Except for the difference in water samples, the other test water samples were measured using the measurement method in Example 1 or Example 2, and the measurement results were observed under a fluorescence microscope. Figure 1 .

[0065] Depend on Figure 1 It can be seen that polyester, polyamide (nylon), polyethylene (PE), and polypropylene (PP) fiber microplastics have a good dyeing effect under the fluorescence microscope, showing a good fluorescent state and can be well distinguished. However, cotton, viscose, linen, sheep wool, mulberry silk, and polyacrylonitrile fibers have a less obvious dyeing effect and show a subtle fluorescent state. In addition, acetate and triacetate fibers are semi-dissolved, with blurred edges, and also have no good dyeing effect, and the fluorescence state is also not obvious.

[0066] It can be seen from this that in an aqueous solution containing a single fiber microplastic or a single other fiber, the measurement method of the present application can be used to well distinguish fiber microplastics through fluorescence microscopy observation.

[0067] Test Example 2

[0068] Compared with Test Example 1, this test example differs in that the test water samples taken are mixed solutions made by artificially mixing different types of textile fibers, namely, mixed water samples of multiple single-fiber microplastics, mixed water samples of multiple single fibers, and mixed water samples of multiple single fibers and single-fiber plastics.

[0069] Among them, mixed water samples of multiple single fibers include: mixed water samples of cotton, viscose and flax; mixed water samples of sheep wool and mulberry silk.

[0070] Mixed water samples of multiple single fiber microplastics include: mixed water samples of nylon and polyester fibers.

[0071] Mixed water samples of various single fibers and single fiber plastics include: mixed water samples of cotton, viscose, linen, and polyester fibers; mixed water samples of sheep wool, mulberry silk, and polyester fibers; mixed water samples of polyacrylonitrile fiber and polyester fibers; mixed water samples of cotton, viscose, linen, and nylon; mixed water samples of sheep wool, mulberry silk, and nylon; mixed water samples of polyacrylonitrile fiber and nylon; mixed water samples of cotton, viscose, linen, and polypropylene; mixed water samples of sheep wool, mulberry silk, and polypropylene; mixed water samples of polyacrylonitrile fiber and polypropylene; mixed water samples of cotton, viscose, linen, and polyethylene; mixed water samples of sheep wool, mulberry silk, and polyethylene; mixed water samples of polyacrylonitrile fiber and polyethylene.

[0072] Similarly, except for the difference in water samples, the determination method in Example 1 or Example 2 was used to measure each test water sample, and the determination results were obtained by fluorescence microscopy. Figure 2 .

[0073] Depend on Figure 2 It can be seen that in the mixed water sample of multiple single fibers, the mixed multiple single fibers still have a poor dyeing effect, and the fluorescence effect is not obvious; in the mixed water sample of multiple single fiber microplastics, the mixed multiple single fiber microplastics still have a good dyeing effect, and show a strong fluorescence state; in the mixed water sample of multiple single fibers and single fiber microplastics, the mixed multiple single fibers still appear darker, and the mixed multiple single fiber microplastics appear better fluorescence.

[0074] It can be seen from this that in a mixed solution of multiple single fibers and single fiber microplastics, using the measurement method of the present application, fibers outside the scope of microplastics will not affect the fluorescent coloration of fiber microplastics, and fiber microplastics can be better identified under a fluorescence microscope.

[0075] That is to say, the microscopic determination method of fiber microplastics in textile aqueous solutions given in this application can eliminate the interference of other fibers in the textile aqueous solution except for fiber microplastics.

[0076] Test Example 3

[0077] Among the types of filter membranes currently in common use, polyamides, polysulfones, fluorinated types, and polyolefins fall into the category of microplastics, which can affect the determination of microplastics. When conducting microplastic determinations, other fields mostly use Whatman black PC etched track membrane (47mm 0.2μm). This membrane can effectively block background epifluorescence and show the fluorescence of the substance to be observed on the membrane, but this membrane is not produced domestically and is expensive. In some fields, ink-dyed organic membranes (50mm 0.22μm) are used instead of PC etched track membranes, which can also block part of the epifluorescence and achieve the convenience of observation. However, the material of organic filter membranes basically falls into the category of microplastics, which also affects the determination of microplastics. In addition, the filter membranes used include cellulose membranes, glass fiber filter paper, and inorganic membranes made of inorganic materials. Among them, cellulose membranes are divided into nitrocellulose membranes, cellulose acetate membranes, and filter membranes mixed with nitric acid and acetate fibers. Nitrocellulose is expensive, and cellulose acetate fibers are soluble in acetone. During filtration, some filter membrane fibers will dissolve, appearing in a semi-dissolved state, making it impossible to perform normal determination.

[0078] A filter membrane mixed with nitric acid and acetic acid fibers, glass fiber filter paper, and alumina filter paper (a type of inorganic membrane) are used as filter membranes in the fiber microplastic determination method of this application for testing. The determination method in Example 1 or Example 2 is used for determination, and when the three filter membranes are used for determination, the step of rinsing with acetone solution is not performed.

[0079] The results of the test are shown in Figure 3-5 , Figure 3 The image shows the observation results of glass fiber filter paper under a fluorescence microscope. Figure 4 The image shows the observation results of the filter membrane mixed with nitric acid and acetic acid fibers under a fluorescence microscope. Figure 5 Shown is the observation result of alumina filter paper under a fluorescence microscope.

[0080] Depend on Figure 3-5 It can be seen that when glass fiber filter paper is used for measurement, there is fluorescence interference in the background of the glass fiber filter paper; when the filter membrane mixed with nitric acid and acetic acid fibers is used for measurement, there is also fluorescence interference, and the cellulose acetate fiber is partially dissolved, showing a semi-dissolved state with blurred edges; when alumina filter paper is used for measurement, there is no fluorescence interference in the alumina filter paper, and it appears as a black film.

[0081] It can be seen from this that, using the determination method of the present application (excluding the acetone rinsing step), the filter membrane of the mixture of nitric acid and acetic acid fibers has fluorescence interference. Although it can achieve the determination of fiber microplastics in aqueous solution, its semi-dissolved and blurred edge state will affect the observation of fiber microplastics, and it is expensive. Although alumina filter paper can achieve the determination of fiber microplastics in aqueous solution, the price of alumina filter paper is more expensive. In contrast, glass fiber filter paper is used for the determination of fiber microplastics in textile aqueous solution. Glass fiber filter paper is cheap, and if the local fluorescence interference can be eliminated, a better measurement effect can be achieved.

[0082] Test Example 4

[0083] When dyeing and filtering with Nile red dye, a small amount of fluorescent dye will remain on the filter membrane, causing background fluorescence on the filter membrane and interfering with the observation of fiber microplastics.

[0084] Compared with Example 1, in this test example, except for not implementing the step of "rinsing the sand core filter device on the filtration device with acetone solution and then rinsing it multiple times with tertiary water", the water samples taken and the other measurement steps of fiber microplastics are the same as in Example 1.

[0085] One of the fields of view of the glass fiber filter membrane observed under a fluorescence microscope in Example 1 and Test Example 4 is shown in FIG. Figure 6 、 Figure 7 and Figure 8 , Figure 6 、 Figure 7 The following figure shows the results of observation under a fluorescence microscope of Example 1. Figure 8 Shown is the result of observation under a fluorescence microscope of Experimental Example 4.

[0086] The measurement results are shown in Tables 1 and 2. Table 1 shows the number and abundance of fiber microplastics obtained by Example 1 under a fluorescence microscope, and Table 2 shows the number and abundance of fiber microplastics obtained by Experimental Example 4 under a fluorescence microscope.

[0087] Table 1

[0088] Number of fiber microplastics / root 146 Fiber microplastic abundance / root / L 73

[0089] Table 2

[0090] Number of fiber microplastics / root Countless Fiber microplastic abundance / root / L Difficult to measure

[0091] pass Figure 6-7 and Figure 8 From the comparison of the results, it can be seen that the background fluorescence of Example 1 is obviously eliminated, and the fiber microplastics emit strong fluorescence under the fluorescence microscope, which does not interfere with their observation. However, the background fluorescence of Experimental Example 4 is more obvious, which interferes with the observation of the fiber microplastics.

[0092] By comparing the results in Table 1 and Table 2, it can be seen that the number and abundance of the obtained fiber microplastics were measured in Example 1, while in Experimental Example 4, it was difficult to measure the number and abundance of fiber microplastics due to the influence of background fluorescence.

[0093] It can be seen from this that the microscopic determination method of fiber microplastics in textile aqueous solutions provided by the present invention can eliminate the interference of background fluorescence in the determination of fiber microplastics in the washing wastewater of black plush fabrics blended with black cotton and polyester fibers, so that only fiber microplastics are counted, which can greatly reduce the missed detection rate of fiber microplastics.

[0094] Test Example 5

[0095] Compared with Example 2, in Test Example 5, except for not implementing the step of "rinsing the sand core filter device on the filtration device with acetone solution and then rinsing it multiple times with tertiary water", the water samples taken and the other measurement steps of fiber microplastics are the same as in Example 2.

[0096] One of the fields of view of the glass fiber filter membrane observed under a fluorescence microscope in Example 2 and Test Example 5 is shown in FIG. Figure 9 and Figure 10 , Figure 9 The following figure shows the results of observation under a fluorescence microscope of Example 2. Figure 10 Shown is the result of observation under a fluorescence microscope of Experimental Example 5.

[0097] The measurement results are shown in Tables 3 and 4. Table 3 shows the number and abundance of fiber microplastics obtained by Example 2 under a fluorescence microscope, and Table 4 shows the number and abundance of fiber microplastics obtained by Experimental Example 5 under a fluorescence microscope.

[0098] Table 3

[0099] Number of fiber microplastics / root 256 Fiber microplastic abundance / root / L 51

[0100] Table 4

[0101] Number of fiber microplastics / root Countless Fiber microplastic abundance / root / L Difficult to measure

[0102] pass Figure 9 and Figure 10 From the comparison of the results, it can be seen that the background fluorescence of Example 2 is obviously eliminated, the fiber microplastics emit strong fluorescence under the fluorescence microscope, and other fibers appear darker in color, which does not interfere with their observation. However, the background fluorescence of Experimental Example 5 is more obvious, which interferes with the observation of the fiber microplastics.

[0103] By comparing the results in Table 3 and Table 4, it can be seen that the number and abundance of the obtained fiber microplastics were measured in Example 2, while in Experimental Example 5, it was difficult to measure the number and abundance of fiber microplastics due to the influence of background fluorescence.

[0104] It can be seen from this that the microscopic determination method of fiber microplastics in textile aqueous solutions provided by the present invention can eliminate the interference of background fluorescence in the determination of fiber microplastics in the washing wastewater of viscose and nylon fiber blended tops, so that only fiber microplastics are counted, which can greatly reduce the missed detection rate of fiber microplastics.

[0105] In summary, combined with Test Examples 3-5, it can be seen that combining the glass fiber filter paper with the acetone rinsing steps to carry out the determination of fiber microplastics can not only eliminate the background fluorescence on the filter paper, realize the quantitative determination of fiber microplastics in textile aqueous solution, and reduce the missed detection rate of fiber microplastics, but also the glass fiber filter paper is cheap, which can reduce the determination cost.

[0106] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for microscopic determination of fiber microplastics in aqueous textile solutions, characterized in that: The following steps are involved: S100, collecting surface wastewater in the environment into a water sampler, and stirring to obtain a uniform water sample; S200, adding biological colorant Nile red into acetone solution to prepare Nile red staining solution; S300, pouring the uniform water sample into a beaker, and adding the prepared Nile red staining solution to perform fluorescent staining on the water sample; S400, after standing for a period of time, filtering the water sample after fluorescent staining using a micro-glass filtration device with a glass fiber filter membrane; S500, flushing the sand core filter device on the suction filtration device with an acetone solution, and then flushing it with tertiary water for multiple times; S600, removing the washed glass fiber filter membrane and placing it in a vacuum oven for drying; S700, placing the dried glass fiber filter on a microscope stage, using a fluorescence microscope at a wavelength of 450-490nm and a magnification of 4X or 10X to observe the fluorescent substance, measure the size, and count.

2. The method for microscopic determination of fiber microplastics in aqueous textile solution according to claim 1, characterized in that: The concentration of the Nile red staining solution prepared in the S200 is 180-220 ug / ml.

3. The method for microscopic determination of fiber microplastics in aqueous solution of textiles according to claim 1, characterized in that: In the S300, Nile red fluorescent dye is added at 1-3 ug / ml.

4. The method for microscopic determination of fiber microplastics in aqueous textile solution according to claim 1, characterized in that: The S400 is allowed to stand for 1-4 hours.

5. The method for microscopic determination of fiber microplastics in aqueous solution of textiles according to claim 1, characterized in that: The amount of the S500 acetone solution is 8-15 ml.

6. The method for microscopic determination of fiber microplastics in aqueous solution of textiles according to claim 1, characterized in that: The drying time in S600 is 1-4 hours.

7. The method for microscopic determination of fiber microplastics in aqueous solution of textiles according to claim 1, characterized in that: The measurement stroke in S700 is: measurement starts from a corner of the glass fiber filter membrane, all fibers in a field of view are counted, and repeated counting is not allowed. After measuring a field of view, move to the adjacent field of view in a direction parallel to the filter membrane to continue measuring, and continue to move the field of view in this direction to measure until one side of the filter membrane, and then move a field of view in a direction perpendicular to this direction, and then move in the opposite direction to measure back to the initial side, and measure in this way along a bow-shaped route until the entire glass fiber filter membrane is measured.

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