Preparation method of aldehyde-removing non-woven fabric, aldehyde-removing non-woven fabric and application thereof

Abstract

This invention discloses a method for preparing formaldehyde-removing nonwoven fabric, comprising the following steps: 1) preparing a formaldehyde-removing solution by mixing 18-24% formaldehyde remover, 1.2-1.6% dispersant, 0.3-0.8% stabilizer, 0.5-0.7% binder, and the remainder water according to a mass percentage; the formaldehyde remover includes ethylene urea, polyaspartic acid-urea graft copolymer, and nitrogen-doped straw-based carbon quantum dots, wherein, by weight, ethylene urea comprises 7-9 parts, polyaspartic acid-urea graft copolymer comprises 4-6 parts, and nitrogen-doped straw-based carbon quantum dots comprises 2-4 parts; 2) passing the nonwoven fabric through a formaldehyde-removing solution tank; 3) squeezing the formaldehyde-removing solution-soaked nonwoven fabric through rollers to remove excess formaldehyde-removing solution; 4) drying the squeezed nonwoven fabric in a drying oven. This invention combines ethylene urea, polyaspartic acid-urea graft copolymer, and nitrogen-doped straw-based carbon quantum dots, which has the advantages of low cost, reduced toxicity of formaldehyde remover, and high long-term formaldehyde removal efficiency.

Description

Technical Field

[0001] This invention relates to the field of methods for preparing formaldehyde-removing nonwoven fabrics, specifically to a method for preparing formaldehyde-removing nonwoven fabrics, formaldehyde-removing nonwoven fabrics, and their applications. Background Technology

[0002] Currently, non-woven fabrics have advantages such as moisture resistance, breathability, flexibility, light weight, non-combustibility, easy decomposition, non-toxicity, non-irritation, rich colors, low price, and recyclability. They have been widely used in various fields such as medical and health care, home decoration, clothing, and air purification.

[0003] "Formaldehyde-removing non-woven fabric filters" are filtration components that use non-woven fabric as a base carrier to load activated carbon, chemical agents, photocatalysts, or other adsorption / decomposition materials, specifically designed to remove gaseous pollutants such as formaldehyde from the air. It is one of the important means of combating indoor formaldehyde pollution in modern air purification equipment. The formaldehyde-removing non-woven fabric used relies on urea, which has extremely low efficiency under normal temperature and humidity conditions and requires high temperature and high pressure (industrial production conditions) to complete curing. Furthermore, the polymer generated in the reaction may decompose in reverse when humidity increases, releasing formaldehyde and urea again, causing secondary pollution. Ethylene urea itself is highly toxic; residual monomers may induce allergies through skin contact or inhalation (ECHA animal experiments show skin sensitization), and its long-term formaldehyde removal efficiency is poor. For environmental protection, it is necessary to reduce the use of ethylene urea and improve long-term formaldehyde removal efficiency. Summary of the Invention

[0004] This invention addresses the aforementioned problems by proposing a method for preparing formaldehyde-removing nonwoven fabric. It overcomes the shortcomings of existing methods, such as the extremely low efficiency of urea under normal temperature and humidity conditions, the need for high temperature and high pressure (industrial production conditions) for curing, and the high toxicity and poor long-term formaldehyde removal efficiency of ethylene urea. For environmental protection, it is necessary to reduce the use of ethylene urea and improve its long-term formaldehyde removal efficiency.

[0005] The technical solution adopted in this invention is as follows: A method for preparing formaldehyde-removing nonwoven fabric includes the following steps: 1) Mix 18-24% formaldehyde remover, 1.2-1.6% dispersant, 0.3-0.8% stabilizer, 0.5-0.7% binder, and the balance water according to mass percentage to prepare a formaldehyde remover solution; the formaldehyde remover includes ethylene urea, polyaspartic acid-urea graft copolymer, and nitrogen-doped straw-based carbon quantum dots, wherein by weight, ethylene urea is 7-9 parts, polyaspartic acid-urea graft copolymer is 4-6 parts, and nitrogen-doped straw-based carbon quantum dots are 2-4 parts; 2) The non-woven fabric passes through the formaldehyde removal liquid tank; 3) Squeeze the non-woven fabric soaked in formaldehyde removal solution through rollers to remove excess formaldehyde removal solution; 4) Dry the extruded nonwoven fabric in a drying oven.

[0006] Optionally, the preparation method of the polyaspartic acid-urea graft copolymer is as follows: by weight, 1-2 parts of polysuccinimide, 1-2 parts of urea and 1-3 parts of sodium ethoxide are reacted at 50-52°C for 10-12 hours to generate the polyaspartic acid-urea graft copolymer.

[0007] Optionally, by weight, nitrogen-doped straw-based carbon quantum dots are prepared by hydrothermal reaction of 1 part crushed straw, 1-2 parts aspartic acid and 2-3 parts oxalic acid at 170-190℃ for 6-8 hours; after the reaction, ultrapure water is added to dissolve and the mixture is stirred for 40-60 minutes to obtain nitrogen-doped straw-based carbon quantum dots.

[0008] Optionally, the dispersant may be one or more of maleate and acrylate.

[0009] Optionally, the stabilizer includes sodium carboxymethyl cellulose and sodium silicate.

[0010] Optionally, the adhesive is one or more of aminosilane and cationic silane.

[0011] Optionally, in step 2), the running speed of the nonwoven fabric is controlled to be 0.3-0.5 m / s throughout the process.

[0012] Optionally, the drying oven temperature is set at 105-120℃ within 5 meters of the inlet, 120-140℃ within 5-20 meters, and a cooling section is set at 20-25 meters to rapidly cool the nonwoven fabric to room temperature.

[0013] The present invention also discloses a formaldehyde-removing nonwoven fabric prepared using the above-described preparation method.

[0014] The present invention also discloses the application of formaldehyde-removing nonwoven fabric on filter screens, wherein the formaldehyde-removing nonwoven fabric is applied to the filter screen after being laminated with hot melt adhesive by different grades of meltblowing.

[0015] In summary, the present invention has the following beneficial effects: 1. The polyaspartic acid-urea graft copolymer in this invention provides abundant free amino groups through urea units, which undergo an irreversible nucleophilic addition reaction with formaldehyde to generate stable hydroxymethylurea derivatives. The reaction rate is fast (more than 10 times faster than activated carbon adsorption) and can be carried out efficiently at room temperature. The carboxyl groups (-COOH) of the polyaspartic acid backbone are combined with hydroxymethylurea through hydrogen bonds to form a three-dimensional cross-linked network structure, which completely fixes formaldehyde on the polymer backbone, blocks secondary release, and is metabolically non-toxic. Nitrogen-doped straw-based carbon quantum dots remove formaldehyde in a green and environmentally friendly way. This invention combines ethylene urea, polyaspartic acid-urea graft copolymer, and nitrogen-doped straw-based carbon quantum dots, making the formaldehyde-removing nonwoven fabric have the advantages of low cost, reduced toxicity of formaldehyde removal agents, and high long-term formaldehyde removal efficiency.

[0016] 2. In this invention, the basis weight of the nonwoven fabric after drying is ensured by controlling the running speed of the nonwoven fabric. The faster the speed, the lower the increase in basis weight of the nonwoven fabric. It is easy to operate and has high control precision.

[0017] 3. By extending the length of the drying oven, the present invention reduces the drying temperature, thereby reducing the risk of copolymer decomposition and resulting in products with higher stability. Attached Figure Description

[0018] Figure 1 This is the chemical reaction formula of the polyaspartic acid-urea graft copolymer in the preparation method of the formaldehyde-removing nonwoven fabric of the present invention. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0020] The main components of this invention are all purchased from commercially available products. For example, ethylene urea was purchased from Hebei Benyu Technology Co., Ltd. The polyaspartic acid used in this invention was purchased from Shandong Yuanlian Chemical Co., Ltd. Example 1:

[0021] like Figure 1 As shown, this invention discloses a method for preparing formaldehyde-removing nonwoven fabric, comprising the following steps: 1) Prepare a formaldehyde removal solution by mixing 18% formaldehyde remover, 1.2% dispersant, 0.3% stabilizer, 0.5% binder, and the balance water according to the following mass percentages. The dispersant is maleate. The stabilizer includes sodium carboxymethyl cellulose. The binder is aminosilane.

[0022] The formaldehyde removal agent includes ethylene urea, polyaspartic acid-urea graft copolymer and nitrogen-doped straw-based carbon quantum dots, wherein, by weight, there are 7 parts of ethylene urea, 4 parts of polyaspartic acid-urea graft copolymer and 2 parts of nitrogen-doped straw-based carbon quantum dots. 2) The non-woven fabric passes through the formaldehyde removal liquid tank; in step 2), the running speed of the non-woven fabric is controlled to be 0.3m / s throughout the process.

[0023] 3) Squeeze the non-woven fabric soaked in formaldehyde removal solution through rollers to remove excess formaldehyde removal solution; 4) The extruded nonwoven fabric is placed in a drying oven for drying. The temperature of the drying oven is controlled at 105°C within 5 meters of the inlet, 120°C within 5 meters, and a cooling section is set at 20 meters to allow the nonwoven fabric to cool down to room temperature rapidly.

[0024] The preparation method of the polyaspartic acid-urea graft copolymer is as follows: by weight, 1 part of polysuccinimide, 1 part of urea and 1 part of sodium ethoxide are reacted at 50°C for 10 hours to generate the polyaspartic acid-urea graft copolymer.

[0025] By weight, nitrogen-doped straw-based carbon quantum dots were obtained by hydrothermal reaction of 1 part crushed straw, 1 part aspartic acid and 2 parts oxalic acid at 170℃ for 6 hours; after the reaction, ultrapure water was added to dissolve the mixture and stirred for 40 minutes. Example 2:

[0026] This invention discloses a method for preparing formaldehyde-removing nonwoven fabric, comprising the following steps: 1) Prepare a formaldehyde removal solution by mixing 24% formaldehyde remover, 1.6% dispersant, 0.8% stabilizer, 0.7% binder, and the balance water according to the following mass percentages. The dispersant is one or more acrylates. The stabilizer includes sodium silicate. The binder is a cationic silane.

[0027] The formaldehyde removal agent includes ethylene urea, polyaspartic acid-urea graft copolymer and nitrogen-doped straw-based carbon quantum dots, wherein, by weight, there are 9 parts of ethylene urea, 6 parts of polyaspartic acid-urea graft copolymer and 4 parts of nitrogen-doped straw-based carbon quantum dots. 2) The non-woven fabric passes through the formaldehyde removal liquid tank; in step 2), the running speed of the non-woven fabric is controlled to be 0.5m / s throughout the process.

[0028] 3) Squeeze the non-woven fabric soaked in formaldehyde removal solution through rollers to remove excess formaldehyde removal solution; 4) The extruded nonwoven fabric is placed in a drying oven for drying. The temperature of the drying oven is controlled at 120°C within 5 meters of the inlet, 140°C within 5-20 meters, and a cooling section is set at 20-25 meters to allow the nonwoven fabric to cool down to room temperature rapidly.

[0029] The preparation method of the polyaspartic acid-urea graft copolymer is as follows: by weight, 2 parts of polysuccinimide, 2 parts of urea and 3 parts of sodium ethoxide are reacted at 52°C for 12 hours to generate the polyaspartic acid-urea graft copolymer.

[0030] By weight, nitrogen-doped straw-based carbon quantum dots were obtained by hydrothermal reaction of 1 part crushed straw, 2 parts aspartic acid and 3 parts oxalic acid at 190℃ for 8 hours; after the reaction, ultrapure water was added to dissolve the mixture and stirred for 60 minutes. Example 3:

[0031] This invention discloses a method for preparing formaldehyde-removing nonwoven fabric, comprising the following steps: 1) Prepare a formaldehyde removal solution by mixing 21% formaldehyde remover, 1.4% dispersant, 0.5% stabilizer, 0.6% binder, and the balance water according to the following mass percentages. The dispersant is one or more acrylates. The stabilizer includes sodium silicate. The binder is an aminosilane.

[0032] The formaldehyde removal agent includes ethylene urea, polyaspartic acid-urea graft copolymer and nitrogen-doped straw-based carbon quantum dots, wherein, by weight, there are 8 parts of ethylene urea, 5 parts of polyaspartic acid-urea graft copolymer and 4 parts of nitrogen-doped straw-based carbon quantum dots. 2) The non-woven fabric passes through the formaldehyde removal liquid tank; in step 2), the running speed of the non-woven fabric is controlled to be 0.4m / s throughout the process.

[0033] 3) Squeeze the non-woven fabric soaked in formaldehyde removal solution through rollers to remove excess formaldehyde removal solution; 4) The extruded nonwoven fabric is placed in a drying oven for drying. The temperature of the drying oven is controlled at 112°C within 5 meters of the inlet, 130°C within 5-20 meters, and a cooling section is set at 20-25 meters to allow the nonwoven fabric to cool down to room temperature rapidly.

[0034] The preparation method of the polyaspartic acid-urea graft copolymer is as follows: by weight, 1 part of polysuccinimide, 1.5 parts of urea and 2 parts of sodium ethoxide are reacted at 51°C for 11 hours to generate the polyaspartic acid-urea graft copolymer.

[0035] By weight, nitrogen-doped straw-based carbon quantum dots were obtained by hydrothermal reaction of 1 part crushed straw, 1.5 parts aspartic acid and 2.5 parts oxalic acid at 180℃ for 7 hours; after the reaction, ultrapure water was added to dissolve the mixture and stirred for 50 minutes to obtain nitrogen-doped straw-based carbon quantum dots.

[0036] Comparative Example 1: This invention discloses a method for preparing formaldehyde-removing nonwoven fabric, comprising the following steps: 1) Prepare a formaldehyde removal solution by mixing 17% formaldehyde remover, 1.1% dispersant, 0.2% stabilizer, 0.4% binder, and the balance water according to the following mass percentages: The dispersant is one or more acrylates. The stabilizer includes sodium silicate. The binder is an aminosilane.

[0037] The formaldehyde removal agent includes ethylene urea, polyaspartic acid-urea graft copolymer and nitrogen-doped straw-based carbon quantum dots, wherein, by weight, there are 6 parts of ethylene urea, 3 parts of polyaspartic acid-urea graft copolymer and 1 part of nitrogen-doped straw-based carbon quantum dots. 2) The non-woven fabric passes through the formaldehyde removal liquid tank; in step 2), the running speed of the non-woven fabric is controlled to be 0.2m / s throughout the process.

[0038] 3) Squeeze the non-woven fabric soaked in formaldehyde removal solution through rollers to remove excess formaldehyde removal solution; 4) The extruded nonwoven fabric is placed in a drying oven for drying. The temperature of the drying oven is controlled at 104℃ within 5 meters of the inlet, 119℃ within 5-20 meters, and a cooling section is set at 20-25 meters to allow the nonwoven fabric to cool down to room temperature rapidly.

[0039] The preparation method of the polyaspartic acid-urea graft copolymer is as follows: by weight, 1 part of polysuccinimide, 0.9 parts of urea and 3.1 parts of sodium ethoxide are reacted at 49°C for 9 hours to generate the polyaspartic acid-urea graft copolymer.

[0040] By weight, nitrogen-doped straw-based carbon quantum dots were obtained by hydrothermal reaction of 1 part crushed straw, 1 part aspartic acid and 3.1 parts oxalic acid at 169℃ for 5 hours; after the reaction, ultrapure water was added to dissolve the mixture and stirred for 39 minutes to obtain nitrogen-doped straw-based carbon quantum dots.

[0041] Comparative Example 2: This invention discloses a method for preparing formaldehyde-removing nonwoven fabric, comprising the following steps: 1) Prepare a formaldehyde removal solution by mixing 25% formaldehyde remover, 1.7% dispersant, 0.3-0.8% stabilizer, 0.8% binder, and the balance water according to the following mass percentages. The dispersant is one or more acrylates. The stabilizer includes sodium silicate. The binder is an aminosilane.

[0042] The formaldehyde removal agent includes ethylene urea, polyaspartic acid-urea graft copolymer and nitrogen-doped straw-based carbon quantum dots, wherein, by weight, there are 10 parts of ethylene urea, 3 parts of polyaspartic acid-urea graft copolymer and 1 part of nitrogen-doped straw-based carbon quantum dots. 2) The non-woven fabric passes through the formaldehyde removal liquid tank; in step 2), the running speed of the non-woven fabric is controlled to be 0.6m / s throughout the process.

[0043] 3) Squeeze the non-woven fabric soaked in formaldehyde removal solution through rollers to remove excess formaldehyde removal solution; 4) The extruded nonwoven fabric is placed in a drying oven for drying. The temperature of the drying oven is controlled at 121°C within 5 meters of the inlet, 141°C within 5-20 meters, and a cooling section is set at 20-25 meters to rapidly cool the nonwoven fabric to room temperature.

[0044] The preparation method of the polyaspartic acid-urea graft copolymer is as follows: by weight, 1-2 parts of polysuccinimide, 1-2 parts of urea and 1-3 parts of sodium ethoxide are reacted at 50-52°C for 10-12 hours to generate the polyaspartic acid-urea graft copolymer.

[0045] By weight, nitrogen-doped straw-based carbon quantum dots were obtained by hydrothermal reaction of 1 part crushed straw, 2.1 parts aspartic acid and 1.9 parts oxalic acid at 191℃ for 8.1 h; after the reaction was completed, ultrapure water was added to dissolve the mixture and stirred for 61 minutes to obtain nitrogen-doped straw-based carbon quantum dots.

[0046] Comparative Example 3: This invention discloses a method for preparing formaldehyde-removing nonwoven fabric, comprising the following steps: 1) Prepare a formaldehyde removal solution by mixing 18% formaldehyde remover, 1.2% dispersant, 0.3% stabilizer, 0.5% binder, and the balance water according to the following mass percentages. The dispersant is one or more acrylates. The stabilizer includes sodium silicate. The binder is an aminosilane.

[0047] The formaldehyde removal agent includes ethylene urea and polyaspartic acid-urea graft copolymer, wherein, by weight, ethylene urea is 7 parts and polyaspartic acid-urea graft copolymer is 4 parts. 2) The non-woven fabric passes through the formaldehyde removal liquid tank; in step 2), the running speed of the non-woven fabric is controlled to be 0.3m / s throughout the process.

[0048] 3) Squeeze the non-woven fabric soaked in formaldehyde removal solution through rollers to remove excess formaldehyde removal solution; 4) The extruded nonwoven fabric is placed in a drying oven for drying. The temperature of the drying oven is controlled at 105℃ within 5 meters of the inlet, 120℃ within 5-20 meters, and a cooling section is set at 20-25 meters to allow the nonwoven fabric to cool down to room temperature rapidly.

[0049] The preparation method of the polyaspartic acid-urea graft copolymer is as follows: by weight, 1 part of polysuccinimide, 1 part of urea and 1 part of sodium ethoxide are reacted at 50°C for 10 hours to generate the polyaspartic acid-urea graft copolymer.

[0050] Comparative Example 4: This invention discloses a method for preparing formaldehyde-removing nonwoven fabric, comprising the following steps: 1) Prepare a formaldehyde removal solution by mixing 18% formaldehyde remover, 1.2% dispersant, 0.3% stabilizer, 0.5% binder, and the balance water according to the following mass percentages. The dispersant is one or more acrylates. The stabilizer includes sodium silicate. The binder is an aminosilane.

[0051] The formaldehyde removal agent includes ethylene urea and nitrogen-doped straw-based carbon quantum dots, wherein, by weight, there are 7 parts ethylene urea and 2 parts nitrogen-doped straw-based carbon quantum dots; 2) The non-woven fabric passes through the formaldehyde removal liquid tank; in step 2), the running speed of the non-woven fabric is controlled to be 0.3m / s throughout the process.

[0052] 3) Squeeze the non-woven fabric soaked in formaldehyde removal solution through rollers to remove excess formaldehyde removal solution; 4) The extruded nonwoven fabric is placed in a drying oven for drying. The temperature of the drying oven is controlled at 105℃ within 5 meters of the inlet, 120℃ within 5-20 meters, and a cooling section is set at 20-25 meters to allow the nonwoven fabric to cool down to room temperature rapidly.

[0053] By weight, nitrogen-doped straw-based carbon quantum dots were obtained by hydrothermal reaction of 1 part crushed straw, 1 part aspartic acid and 2 parts oxalic acid at 170℃ for 6 hours; after the reaction, ultrapure water was added to dissolve the mixture and stirred for 40 minutes.

[0054] The present invention also discloses a formaldehyde-removing nonwoven fabric prepared using the above-described preparation method.

[0055] This invention also discloses the application of formaldehyde-removing nonwoven fabric in filter screens, wherein the formaldehyde-removing nonwoven fabric is applied to the filter screen after being laminated with hot melt adhesive through different grades of meltblowing. Commonly used spinnerets have microfiltration efficiencies for 0.3-micron particles ranging from 90% to 99.995%.

[0056] The term "meltblown" in this invention generally refers to the meltblown nonwoven process and the material made by this process—meltblown fabric.

[0057] Specifically, polymer chips (most commonly polypropylene (PP), but also polyester (PET), polyamide (PA), etc.) are used as raw materials. This invention uses a screw extruder to heat and melt the polymer into a melt. The melt is extruded from the micropores of a spinneret, forming fine streams. These streams are stretched, refined, and cooled using a high-temperature, high-speed airflow (usually hot air). The stretched ultrafine fibers are randomly laid on a receiving device (such as a mesh curtain or roller), where they entangle and bond together using their own residual heat or thermal adhesion. This ultimately forms a continuous nonwoven fabric with a random fiber structure.

[0058] Performance testing: Formaldehyde removal experiment: The products prepared in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, 4 were subjected to formaldehyde removal experiments. The test methods were strictly carried out in accordance with the industry standard QB / T2761-2006.

[0059] The experimental data obtained are shown in Table 1 below: Table 1: Formaldehyde removal test data of Examples 1, 2, 3 and Comparative Examples 1, 2, 3, 4 2) Formaldehyde removal durability test: Formaldehyde removal durability is an important indicator of the formaldehyde removal performance of nonwoven fabrics. The products prepared in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, 4 were subjected to a periodic formaldehyde removal test with an experimental cycle of 50 days. The formaldehyde removal rate was obtained by testing according to QB / T2761-2006.

[0060] Comparing Examples 1, 2, and 3 with Comparative Examples 1 and 2, it is evident that the formaldehyde removal effect of Comparative Examples 1 and 2, which exceed the process range, is significantly reduced, and the removal rate decreases rapidly after 30 days. Comparing Examples 1, 2, and 3 with Comparative Examples 3 and 4, it is evident that the mixtures of ethylene urea and polyaspartic acid-urea graft copolymer, and the mixture of ethylene urea and nitrogen-doped straw-based carbon quantum dots, are not as effective as the composite mixture of ethylene urea, polyaspartic acid-urea graft copolymer, and nitrogen-doped straw-based carbon quantum dots described in this application.

[0061] The above description is merely a preferred embodiment of the present invention and does not limit the scope of patent protection of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, whether directly or indirectly applied to other related technical fields, are similarly included within the scope of protection of the present invention.

Claims

1. A method for preparing a formaldehyde-removing nonwoven fabric, characterized in that, Includes the following steps: 1) Mix 18-24% formaldehyde remover, 1.2-1.6% dispersant, 0.3-0.8% stabilizer, 0.5-0.7% binder, and the balance water according to mass percentage to prepare a formaldehyde remover solution; the formaldehyde remover includes ethylene urea, polyaspartic acid-urea graft copolymer, and nitrogen-doped straw-based carbon quantum dots, wherein by weight, ethylene urea is 7-9 parts, polyaspartic acid-urea graft copolymer is 4-6 parts, and nitrogen-doped straw-based carbon quantum dots are 2-4 parts; 2) The non-woven fabric passes through the formaldehyde removal liquid tank; 3) The non-woven fabric soaked in formaldehyde removal solution is squeezed by rollers to remove excess formaldehyde removal solution; 4) Place the extruded nonwoven fabric in a drying oven to dry; The preparation method of the polyaspartic acid-urea graft copolymer is as follows: 1-2 parts by weight of polysuccinimide, 1-2 parts by weight of urea, and 1-3 parts by weight of sodium ethoxide are reacted at 50-52℃ for 10-12 hours to generate the polyaspartic acid-urea graft copolymer; 1 part by weight of pulverized straw, 1-2 parts by weight of aspartic acid, and 2-3 parts by weight of oxalic acid are subjected to a hydrothermal reaction at 170-190℃ for 6-8 hours; after the reaction, ultrapure water is added to dissolve the pulverized straw, and the mixture is stirred for 40-60 minutes to obtain nitrogen-doped straw-based carbon quantum dots; the formaldehyde-removing nonwoven fabric is applied to the filter screen after being laminated with hot melt adhesive through different grades of meltblown fabric. In step 2), the running speed of the nonwoven fabric is controlled to be 0.3-0.5 m / s throughout the process; the temperature of the drying oven is set at 105-120℃ within 5 meters of the inlet, 120-140℃ within 5-20 meters, and a cooling section is set at 20-25 meters to allow the temperature of the nonwoven fabric to be rapidly cooled to room temperature.

2. The method for preparing a formaldehyde-removing nonwoven fabric as described in claim 1, characterized in that, The dispersant is one or more of maleate and acrylate.

3. The method for preparing a formaldehyde-removing nonwoven fabric as described in claim 1, characterized in that, The stabilizers include sodium carboxymethyl cellulose and sodium silicate.

4. The method for preparing a formaldehyde-removing nonwoven fabric as described in claim 1, characterized in that, The adhesive is one or more of aminosilane and cationic silane.

5. A formaldehyde-removing nonwoven fabric, characterized in that, The formaldehyde-removing nonwoven fabric is made using the method for preparing formaldehyde-removing nonwoven fabric as described in any one of claims 1 to 4.

6. An application of a formaldehyde-removing nonwoven fabric in a filter screen, characterized in that, The formaldehyde-removing nonwoven fabric is the formaldehyde-removing nonwoven fabric as described in claim 5, wherein the formaldehyde-removing nonwoven fabric is applied to the filter screen after being laminated with hot melt adhesive by different grades of meltblowing.

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