A high-temperature flue gas filter material and preparation method thereof

Abstract

The invention relates to the field of filter materials, and specifically to a high-temperature flue gas filter material and a preparation method thereof. A high-temperature resistant composite fiber web is prepared by a hydroentanglement process using polyphenylene sulfide fibers and modified polyimide fibers. The composite fiber web is used as a receiving substrate, and a composite polyimide fiber layer is prepared on the composite fiber web by electrostatic spinning and gradient heating treatment to construct a filtering gradient structure. The polyimide fiber is modified, and an aminopyridine-based conjugated microporous polymer is introduced on the surface of the polyimide fiber by excitation of a diazirine group by ultraviolet light. Composite carbon dots are introduced into a spinning solution. The aminopyridine-based conjugated microporous polymer with excellent antibacterial, antifouling and high-temperature resistance is used as a substrate. Water-soluble carbon dots using sodium citrate, aminopyrazine and ethylenediamine as raw materials are grown in situ on the surface of the substrate by a hydrothermal method, thereby giving the filter material excellent anti-aging and antibacterial properties, thereby extending its service life.

Description

Technical Field

[0001] The invention relates to the field of filter materials, in particular to a high-temperature smoke filter material and a preparation method thereof. Background Art

[0002] In modern society, one of the main sources of haze is the emission of industrial smoke, the fine particles in which are particularly harmful to human health. Controlling the emission of dusty smoke from industrial furnaces has always been a research hotspot in the field of environmental protection. However, high-temperature flue gas filtration has high requirements on the performance of the filter materials used. In addition to intercepting fine particles, it is also hoped that the filter materials have the ability to decompose organic pollutants such as formaldehyde and kill bacteria and fungi in the air. At present, the market uses more needle-punched, hydroentangled, coated and other filter materials, which have problems such as insufficient filtration efficiency for small-sized particles, poor antibacterial properties, or the use of fluorine-containing compounds to improve performance.

[0003] For example, the surface of the filter material disclosed in Chinese patent CN108465298A is a microporous coating formed by mutual bonding of fluorine-containing polymer resin powders, and the bottom layer is a fiber material. Although the filtering accuracy and service life of the filter material are improved, the use of fluorine-containing polymer resin powders does not conform to the current green environmental protection concept. Summary of the invention

[0004] The object of the present invention is to provide a high-temperature smoke filter material and a preparation method thereof to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for preparing a high-temperature smoke filter material comprises the following steps:

[0007] S1: opening, carding, cross-laying, hydroentanglement, and drying the polyphenylene sulfide fiber and the modified polyimide fiber in sequence to obtain a composite fiber web;

[0008] S2: preparing a fiber spinning solution containing composite carbon dots using diaminodiphenyl ether, N,N-dimethylformamide, pyromellitic acid dianhydride and composite carbon dots;

[0009] S3: Using the composite fiber web as a receiving substrate, electrospinning is performed to receive a fiber spinning solution containing composite carbon dots, and gradient temperature treatment is performed to form a composite polyimide fiber layer to obtain a high-temperature flue gas filter material.

[0010] Furthermore, the mass ratio of the polyphenylene sulfide fiber to the modified polyimide fiber in the composite fiber web is 1:1; the gram weight of the composite fiber web is 82-88 g / m 2 .

[0011] Furthermore, the water pressure used in the hydroentanglement is 88-92 bar.

[0012] Furthermore, the preparation of a fiber spinning solution containing composite carbon dots includes the following steps: under nitrogen protection, diaminodiphenyl ether and N,N-dimethylformamide are mixed, transferred to a 0°C ice bath, pyromellitic anhydride is added, and the mixture is kept warm for 5-6 hours. Composite carbon dots are added and stirred for 1-2 hours to obtain a fiber spinning solution containing composite carbon dots.

[0013] Furthermore, the working conditions of electrospinning are: spinning voltage of 28 kV, spinning spacing of 16-18 cm, temperature of 20-30° C., and relative humidity of 20-30%.

[0014] Furthermore, the working conditions of the gradient temperature increase are: keep warm at 98-102°C for 85-95 min, heat to 218-222°C for 55-65 min, heat to 298-302°C for 55-65 min.

[0015] Furthermore, the preparation of the composite carbon dots includes the following steps:

[0016] Sodium citrate, aminopyrazine, ethylenediamine and deionized water were mixed, the pH was adjusted to 7, aminopyridyl conjugated microporous polymer was added, ultrasonic stirring was performed for 20-30 minutes, the mixture was transferred to a reaction kettle, and the mixture was kept at 158-162° C. for 5-6 hours to obtain composite carbon dots.

[0017] Furthermore, the usage ratio of diaminodiphenyl ether, pyromellitic acid dianhydride, and composite carbon dots is 10 mmol: 10.4 mmol: (0.18-0.21) g.

[0018] Further, the preparation of the modified polyimide fiber comprises the following steps:

[0019] (1) ultrasonically cleaning the polyimide fiber with deionized water and methanol in sequence, drying, spraying 4-[3-(trifluoromethyl)-3H-diaziridin-3-yl]benzyl bromide onto the surface of the polyimide fiber, irradiating with 365 nm ultraviolet light for 5 min, washing, and drying to obtain a pretreated polyimide fiber;

[0020] (2) Methanol and aminopyridine-based conjugated microporous polymer are mixed, and the pretreated polyimide fiber is impregnated with the mixture, ultrasonically treated for 1-2 hours, and then kept at 25-35° C. for 8-10 hours to obtain a modified polyimide fiber.

[0021] Further, the preparation of the aminopyridyl conjugated microporous polymer comprises the following steps:

[0022] In a nitrogen atmosphere, 1,3,5-triethynylbenzene, 2-amino-3,5-dibromopyridine, cuprous iodide, tetrakis(triphenylphosphine)palladium(0), toluene and triethylamine are mixed, heated to 78°C and kept warm until gelation occurs, stirring is stopped, the temperature is raised to 82-84°C and kept warm for 70-72 hours, the mixture is washed with chloroform, acetone, water and methanol for 3-5 times in sequence, washed in a methanol Soxhlet extraction apparatus for 72 hours, dried, crushed and ground to obtain an aminopyridine-based conjugated microporous polymer.

[0023] Beneficial effects of the present invention:

[0024] The present invention provides a high-temperature flue gas filter material and a preparation method thereof. A high-temperature resistant composite fiber web is prepared by a hydroentanglement process using polyphenylene sulfide fiber and modified polyimide fiber. The composite fiber web is used as a receiving substrate. Electrospinning and gradient heating treatment are used to prepare a composite polyimide fiber layer on the composite fiber web to construct a filtering gradient structure, thereby improving the filtering efficiency, antibacterial property and anti-aging property of the filter material.

[0025] In the present invention, polyphenylene sulfide fiber and modified polyimide fiber are used to prepare a high-temperature resistant composite fiber web through a spunlace process. In order to improve the antibacterial property of the composite fiber web, the polyimide fiber is modified, and the diaziridine group is excited by ultraviolet light to generate a disordered and instantaneous insertion reaction of carbene free radicals on adjacent CH bonds, and an aminopyridine-based conjugated microporous polymer is introduced on the surface of the polyimide fiber. The aminopyridine-based conjugated microporous polymer is synthesized using 1,3,5-triethynylbenzene and 2-amino-3,5-dibromopyridine as reaction precursors, and the aminopyridine antibacterial active group is introduced into a porous skeleton in the form of a covalent bond, and then introduced into the composite fiber web, so as to give the composite fiber web excellent antibacterial, antifouling and high-temperature resistance, and improve the filtration efficiency of the composite fiber web.

[0026] In order to construct a gradient filtration structure, a composite fiber web is used as a substrate, a fiber spinning solution containing composite carbon dots is received, and the temperature is increased gradiently for imidization treatment, so that the polyamic acid is melted and bonded to the composite fiber web, so that the composite polyimide fiber layer and the composite fiber web are composited together, avoiding the disadvantages of the composite polyimide fiber layer prepared by electrospinning being very easy to peel off and separate from other supporting materials. The present invention utilizes the melt cross-linking of the nanofibers themselves to composite with the base fabric. Compared with adhesive bonding, while improving the strength, it can not only keep the pore structure of the composite polyimide fiber layer from being blocked and damaged, but also ensure that the filtration efficiency is not affected.

[0027] In order to improve the antibacterial and anti-ultraviolet aging properties of the composite polyimide fiber layer, composite carbon dots were introduced into the spinning solution. Aminopyridine-based conjugated microporous polymer with excellent antibacterial, antifouling and high temperature resistance was used as the substrate. Water-soluble carbon dots with sodium citrate, aminopyrazine and ethylenediamine as raw materials were grown in situ on its surface through a hydrothermal method, giving the filter material excellent anti-aging and antibacterial properties, thereby extending its service life. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, and back, the directional indication is only used to explain a specific posture such as the relative position relationship between the components, the movement status, etc. If the specific posture changes, the directional indication will also change accordingly. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0030] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0031] Embodiment 1: A method for preparing a high-temperature smoke filter material, comprising the following steps:

[0032] S1: opening, carding, cross-laying, hydroentanglement, and drying the polyphenylene sulfide fiber and the modified polyimide fiber in sequence to obtain a composite fiber web;

[0033] The mass ratio of polyphenylene sulfide fiber to modified polyimide fiber in the composite fiber web is 1:1;

[0034] The gram weight of the composite fiber web is 82 g / m2; the water pressure used in the hydroentanglement is 88 bar;

[0035] The preparation of the modified polyimide fiber comprises the following steps:

[0036] (1) 2 g of polyimide fiber was ultrasonically cleaned with deionized water and methanol in sequence, and then dried. 5 μL of 4-[3-(trifluoromethyl)-3H-diaziridin-3-yl]benzyl bromide was sprayed onto the surface of the polyimide fiber, and then irradiated under 365 nm ultraviolet light for 5 min, washed, and dried to obtain pretreated polyimide fiber.

[0037] (2) 10 mL of methanol and 1 g of aminopyridine-based conjugated microporous polymer were mixed, 2 g of pretreated polyimide fiber was impregnated, ultrasonic treatment was performed for 1 h, and then the mixture was kept at 25 °C for 10 h to obtain modified polyimide fiber;

[0038] The preparation of the aminopyridyl conjugated microporous polymer comprises the following steps:

[0039] In a nitrogen atmosphere, 4mmol 1,3,5-triethynylbenzene, 4mmol 2-amino-3,5-dibromopyridine, 100mg cuprous iodide, 240mg tetrakis(triphenylphosphine)palladium(0), 15mL toluene, and 15mL triethylamine were mixed, heated to 78°C and kept until gelation, and then stirring was stopped. The mixture was heated to 82°C and kept for 72h, and washed with chloroform, acetone, water, and methanol three times in sequence, and washed in a methanol Soxhlet extraction device for 72h, dried, crushed, and ground to obtain an aminopyridine-based conjugated microporous polymer.

[0040] S2: preparing a fiber spinning solution containing composite carbon dots using diaminodiphenyl ether, N,N-dimethylformamide, pyromellitic acid dianhydride and composite carbon dots;

[0041] The preparation of the fiber spinning solution containing composite carbon dots comprises the following steps: under nitrogen protection, 10 mmol of diaminodiphenyl ether and 200 mL of N,N-dimethylformamide are mixed, transferred to a 0° C. ice bath, 10.4 mmol of pyromellitic anhydride is added, the mixture is kept warm for 5 hours, 0.18 g of composite carbon dots is added, and the mixture is stirred for 1 hour to obtain a fiber spinning solution containing composite carbon dots;

[0042] S3: using the composite fiber web as a receiving substrate, performing electrospinning, receiving a fiber spinning solution containing composite carbon dots, performing gradient temperature treatment, forming a composite polyimide fiber layer, and obtaining a high-temperature smoke filter material;

[0043] The working conditions of electrospinning were: spinning voltage 28 kV, spinning spacing 16 cm, temperature 20 °C, and relative humidity 20%;

[0044] The working conditions of gradient heating were: keep at 98°C for 95 min, heat to 218°C for 55 min, heat to 298°C for 65 min;

[0045] The preparation of the composite carbon dots comprises the following steps:

[0046] 3.34 g of sodium citrate, 0.5 g of aminopyrazine, 3 mL of ethylenediamine, and 40 mL of deionized water were mixed, the pH was adjusted to 7, 3 g of aminopyridyl conjugated microporous polymer was added, ultrasonic stirring was performed for 20 min, the mixture was transferred to a reaction kettle, and the mixture was kept at 158° C. for 6 h to obtain composite carbon dots.

[0047] Embodiment 2: A method for preparing a high-temperature smoke filter material, comprising the following steps:

[0048] S1: opening, carding, cross-laying, hydroentanglement, and drying the polyphenylene sulfide fiber and the modified polyimide fiber in sequence to obtain a composite fiber web;

[0049] The mass ratio of polyphenylene sulfide fiber to modified polyimide fiber in the composite fiber web is 1:1;

[0050] The gram weight of the composite fiber web is 85 g / m2; the water pressure used in the hydroentanglement is 89 bar;

[0051] The preparation of the modified polyimide fiber comprises the following steps:

[0052] (1) 2 g of polyimide fiber was ultrasonically cleaned with deionized water and methanol in sequence, and then dried. 5 μL of 4-[3-(trifluoromethyl)-3H-diaziridin-3-yl]benzyl bromide was sprayed onto the surface of the polyimide fiber, and then irradiated under 365 nm ultraviolet light for 5 min, washed, and dried to obtain pretreated polyimide fiber.

[0053] (2) 10 mL of methanol and 1 g of aminopyridine-based conjugated microporous polymer were mixed, 2 g of pretreated polyimide fiber was impregnated, ultrasonic treatment was performed for 1.5 h, and then the mixture was kept at 30 °C for 9 h to obtain modified polyimide fiber;

[0054] The preparation of the aminopyridyl conjugated microporous polymer comprises the following steps:

[0055] In a nitrogen atmosphere, 4mmol 1,3,5-triethynylbenzene, 4mmol 2-amino-3,5-dibromopyridine, 100mg cuprous iodide, 240mg tetrakis(triphenylphosphine)palladium(0), 15mL toluene, and 15mL triethylamine were mixed, heated to 78°C and kept until gelation, and then stirring was stopped, heated to 83°C and kept for 71h, washed with chloroform, acetone, water, and methanol four times in sequence, washed in a methanol Soxhlet extraction device for 72h, dried, crushed, and ground to obtain an aminopyridine-based conjugated microporous polymer;

[0056] S2: preparing a fiber spinning solution containing composite carbon dots using diaminodiphenyl ether, N,N-dimethylformamide, pyromellitic acid dianhydride and composite carbon dots;

[0057] The preparation of the fiber spinning solution containing composite carbon dots comprises the following steps: under nitrogen protection, 10 mmol of diaminodiphenyl ether and 200 mL of N,N-dimethylformamide are mixed, transferred to a 0° C. ice bath, 10.4 mmol of pyromellitic anhydride is added, the mixture is kept warm for 5.5 hours, 0.19 g of composite carbon dots is added, and the mixture is stirred for 1.5 hours to obtain a fiber spinning solution containing composite carbon dots;

[0058] S3: using the composite fiber web as a receiving substrate, performing electrospinning, receiving a fiber spinning solution containing composite carbon dots, performing gradient temperature treatment, forming a composite polyimide fiber layer, and obtaining a high-temperature smoke filter material;

[0059] The working conditions of electrospinning were: spinning voltage 28 kV, spinning spacing 17 cm, temperature 25 °C, and relative humidity 25%;

[0060] The working conditions of gradient heating are: keep at 100℃ for 90min, heat to 220℃ for 60min, heat to 300℃ for 60min;

[0061] The preparation of the composite carbon dots comprises the following steps:

[0062] 3.34 g of sodium citrate, 0.5 g of aminopyrazine, 3 mL of ethylenediamine, and 40 mL of deionized water were mixed, the pH was adjusted to 7, 3 g of aminopyridyl conjugated microporous polymer was added, ultrasonic stirring was performed for 25 min, the mixture was transferred to a reaction kettle, and the mixture was kept at 160° C. for 5.5 h to obtain composite carbon dots.

[0063] Embodiment 3: A method for preparing a high-temperature smoke filter material, comprising the following steps:

[0064] S1: opening, carding, cross-laying, hydroentanglement, and drying the polyphenylene sulfide fiber and the modified polyimide fiber in sequence to obtain a composite fiber web;

[0065] The mass ratio of polyphenylene sulfide fiber to modified polyimide fiber in the composite fiber web is 1:1;

[0066] The gram weight of the composite fiber web is 88 g / m2; the water pressure used in the hydroentanglement is 92 bar;

[0067] The preparation of the modified polyimide fiber comprises the following steps:

[0068] (1) 2 g of polyimide fiber was ultrasonically cleaned with deionized water and methanol in sequence, and then dried. 5 μL of 4-[3-(trifluoromethyl)-3H-diaziridin-3-yl]benzyl bromide was sprayed onto the surface of the polyimide fiber, and then irradiated under 365 nm ultraviolet light for 5 min, washed, and dried to obtain pretreated polyimide fiber.

[0069] (2) 10 mL of methanol and 1 g of aminopyridine-based conjugated microporous polymer were mixed, 2 g of pretreated polyimide fiber was impregnated, ultrasonic treatment was performed for 2 h, and then the mixture was kept at 35 °C for 8 h to obtain modified polyimide fiber;

[0070] The preparation of the aminopyridyl conjugated microporous polymer comprises the following steps:

[0071] In a nitrogen atmosphere, 4mmol 1,3,5-triethynylbenzene, 4mmol 2-amino-3,5-dibromopyridine, 100mg cuprous iodide, 240mg tetrakis(triphenylphosphine)palladium(0), 15mL toluene, and 15mL triethylamine were mixed, heated to 78°C and kept until gelation, and then stirring was stopped. The mixture was heated to 84°C and kept for 70h, and washed with chloroform, acetone, water, and methanol for 5 times in sequence, and washed in a methanol Soxhlet extraction device for 72h, dried, crushed, and ground to obtain an aminopyridine-based conjugated microporous polymer.

[0072] S2: preparing a fiber spinning solution containing composite carbon dots using diaminodiphenyl ether, N,N-dimethylformamide, pyromellitic acid dianhydride and composite carbon dots;

[0073] The preparation of the fiber spinning solution containing composite carbon dots comprises the following steps: under nitrogen protection, 10 mmol of diaminodiphenyl ether and 200 mL of N,N-dimethylformamide are mixed, transferred to a 0° C. ice bath, 10.4 mmol of pyromellitic anhydride is added, the mixture is kept warm for 6 hours, 0.21 g of composite carbon dots is added, and the mixture is stirred for 2 hours to obtain a fiber spinning solution containing composite carbon dots;

[0074] S3: using the composite fiber web as a receiving substrate, performing electrospinning, receiving a fiber spinning solution containing composite carbon dots, performing gradient temperature treatment, forming a composite polyimide fiber layer, and obtaining a high-temperature smoke filter material;

[0075] The working conditions of electrospinning were: spinning voltage 28 kV, spinning spacing 18 cm, temperature 30 °C, and relative humidity 30%;

[0076] The working conditions of gradient heating are: keep at 102℃ for 85min, heat to 222℃ for 55min, heat to 302℃ for 55min;

[0077] The preparation of the composite carbon dots comprises the following steps:

[0078] 3.34 g of sodium citrate, 0.5 g of aminopyrazine, 3 mL of ethylenediamine, and 40 mL of deionized water were mixed, the pH was adjusted to 7, 3 g of aminopyridyl conjugated microporous polymer was added, ultrasonic stirring was performed for 30 min, the mixture was transferred to a reaction kettle, and the mixture was kept at 162° C. for 5 h to obtain composite carbon dots.

[0079] Comparative Example 1: Taking Example 3 as the control group, the modified polyimide fiber was replaced by polyimide fiber, and the other processes were normal.

[0080] Comparative Example 2: Example 3 was used as the control group, no composite carbon dots were prepared, and other processes were normal.

[0081] Comparative Example 3: Example 3 was used as a control group, aminopyridyl conjugated microporous polymer was not prepared, and other processes were normal.

[0082] In the examples and comparative examples, the thickness of the composite fiber web was 1 mm, and the thickness of the composite polyimide fiber layer was 0.2 mm.

[0083] Source of raw materials:

[0084] Polyphenylene sulfide fiber (2.2 dtex) was obtained by melt spinning (polyphenylene sulfide: Zhejiang Xinhecheng Co., Ltd.), doubling and twisting; polyimide fiber KD-WFB08403: Jiangsu Kaidun New Materials Co., Ltd.; 4-[3-(trifluoromethyl)-3H-diaziridin-3-yl]benzyl bromide T162224, 1,3,5-triethynylbenzene T162680, 2-amino-3,5-dibromopyridine A151580, iodinated Cuprous acid C433811, tetrakis(triphenylphosphine)palladium(0) T359229, triethylamine T103285, diaminodiphenyl ether D104463, N,N-dimethylformamide D111999, pyromellitic dianhydride P109616, sodium citrate S189183, aminopyrazine A111242, ethylenediamine E112132: Aladdin reagent; methanol, toluene, chloroform, acetone, analytical grade: Sinopharm reagent.

[0085] Performance test: The filter materials prepared in the examples and comparative examples were tested:

[0086] Filtration efficiency: The test was conducted using an automatic filter material filtration tester. The aerosol particle model selected 0.3μm NaCl particles, the air flow rate was 85L / min, the test area was 100cm2, and the filtration efficiency was tested after the filter material was kept at 280℃ for 12h. Antibacterial property: The test was conducted in accordance with GB / T21866-2008, and Staphylococcus aureus was used as the test strain. Anti-aging property: The antibacterial rate was measured again after irradiation with an ultraviolet lamp with a wavelength of 365nm for 3d, and compared with the initial antibacterial rate. If the difference in antibacterial rate was less than 1% (including 1%), the anti-aging property was excellent, otherwise it was unqualified. The results are shown in Table 1.

[0087] Table 1

[0088]

[0089] The present invention provides a high-temperature flue gas filter material and a preparation method thereof. A high-temperature resistant composite fiber web is prepared by a hydroentanglement process using polyphenylene sulfide fiber and modified polyimide fiber. The composite fiber web is used as a receiving substrate. Electrospinning and gradient heating treatment are used to prepare a composite polyimide fiber layer on the composite fiber web to construct a filtering gradient structure, thereby improving the filtering efficiency, antibacterial property and anti-aging property of the filter material.

[0090] By comparing Example 3 with Comparative Example 1 and Comparative Example 3, it can be seen that in the present invention, polyphenylene sulfide fibers and modified polyimide fibers are used to prepare a high-temperature resistant composite fiber web through a spunlace process. In order to improve the antibacterial property of the composite fiber web, the polyimide fiber is modified, and the diaziridine group is excited by ultraviolet light to produce a disordered and instantaneous insertion reaction of carbene free radicals on adjacent CH bonds, and an aminopyridine-based conjugated microporous polymer is introduced on the surface of the polyimide fiber, wherein the aminopyridine-based conjugated microporous polymer is synthesized using 1,3,5-triethynylbenzene and 2-amino-3,5-dibromopyridine as reaction precursors, and the aminopyridine antibacterial active group is introduced into the porous skeleton of CMP in the form of a covalent bond, and is introduced into the composite fiber web, thereby giving the composite fiber web excellent antibacterial, antifouling and high-temperature resistance, and improving the filtration efficiency of the composite fiber web.

[0091] By comparing Example 3 with Comparative Example 2 and Comparative Example 3, it can be seen that in order to improve the antibacterial and UV aging resistance of the composite polyimide fiber layer, composite carbon dots are introduced into the spinning solution, and an aminopyridine-based conjugated microporous polymer with excellent antibacterial, antifouling and high temperature resistance is used as the substrate. Through a hydrothermal method, water-soluble carbon dots with sodium citrate, aminopyrazine and ethylenediamine as raw materials are in situ grown on its surface, giving the filter material excellent anti-aging and antibacterial properties, thereby extending its service life.

[0092] The above descriptions are only embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the present invention specification under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a high-temperature flue gas filter material, characterized in that: The following steps are involved: S1: opening, carding, cross-laying, hydroentanglement, and drying the polyphenylene sulfide fiber and the modified polyimide fiber in sequence to obtain a composite fiber web; S2: preparing a fiber spinning solution containing composite carbon dots using diaminodiphenyl ether, N,N-dimethylformamide, pyromellitic acid dianhydride and composite carbon dots; S3: using the composite fiber web as a receiving substrate, performing electrospinning, receiving a fiber spinning solution containing composite carbon dots, performing gradient temperature treatment, forming a composite polyimide fiber layer, and obtaining a high-temperature smoke filter material; The preparation of the composite carbon dots comprises the following steps: Sodium citrate, aminopyrazine, ethylenediamine and deionized water were mixed, the pH was adjusted to 7, aminopyridyl conjugated microporous polymer was added, ultrasonic stirring was performed for 20-30 minutes, the mixture was transferred to a reaction kettle, and the mixture was kept at 158-162°C for 5-6 hours to obtain composite carbon dots; The preparation of the modified polyimide fiber comprises the following steps: (1) ultrasonically cleaning the polyimide fiber with deionized water and methanol in sequence, drying, spraying 4-[3-(trifluoromethyl)-3H-bis(aziridine-3-yl)benzyl bromide onto the surface of the polyimide fiber, irradiating the fiber with 365 nm ultraviolet light for 5 min, washing, and drying to obtain a pretreated polyimide fiber; (2) Methanol and aminopyridine-based conjugated microporous polymer are mixed, and the pretreated polyimide fiber is impregnated, ultrasonically treated for 1-2 hours, and then kept at 25-35° C. for 8-10 hours to obtain a modified polyimide fiber; The preparation of the aminopyridyl conjugated microporous polymer comprises the following steps: In a nitrogen atmosphere, 1,3,5-triethynylbenzene, 2-amino-3,5-dibromopyridine, cuprous iodide, tetrakis(triphenylphosphine)palladium(0), toluene and triethylamine are mixed, heated to 78°C and kept warm until gelation occurs, stirring is stopped, the temperature is raised to 82-84°C and kept warm for 70-72 hours, the mixture is washed with chloroform, acetone, water and methanol for 3-5 times in sequence, washed in a methanol Soxhlet extraction apparatus for 72 hours, dried, crushed and ground to obtain an aminopyridine-based conjugated microporous polymer.

2. The method for preparing a high-temperature flue gas filter material according to claim 1, characterized in that: The mass ratio of polyphenylene sulfide fiber to modified polyimide fiber in the composite fiber web is 1:1; the gram weight of the composite fiber web is 82-88 g / m 2 The water pressure used in the hydroentanglement is 88-92 bar.

3. The method for preparing a high-temperature flue gas filter material according to claim 1, characterized in that: The preparation of the fiber spinning solution containing composite carbon dots comprises the following steps: under nitrogen protection, diaminodiphenyl ether and N,N-dimethylformamide are mixed, transferred to a 0°C ice bath, pyromellitic anhydride is added, the temperature is kept for 5-6 hours, the composite carbon dots are added, and the spinning solution containing composite carbon dots is stirred for 1-2 hours to obtain a fiber spinning solution containing composite carbon dots.

4. The method for preparing a high-temperature flue gas filter material according to claim 3, characterized in that: The usage ratio of the diaminodiphenyl ether, pyromellitic acid dianhydride and composite carbon dots is 10 mmol: 10.4mmol: (0.18-0.21) g.

5. The method for preparing a high-temperature flue gas filter material according to claim 1, characterized in that: The working conditions of electrospinning are: spinning voltage of 28 kV, spinning spacing of 16-18 cm, temperature of 20-30 °C, and relative humidity of 20-30%.

6. The method for preparing a high-temperature flue gas filter material according to claim 1, characterized in that: The working conditions of gradient heating are: keep warm at 98-102℃ for 85-95min, heat to 218-222℃ for 55-65min, heat to 298-302℃ for 55-65min.

7. A high-temperature flue gas filter material, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 6.

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