A method for preparing a dioxin adsorbing fiber membrane

Abstract

The application discloses a preparation method of a dioxin adsorption fiber membrane, and the preparation method is characterized in that: graphite is heated and treated under a high-temperature ammonia atmosphere to prepare a nitrogen-doped graphdiyne adsorbent, then the nitrogen-doped graphdiyne adsorbent, a nano chalcogen compound and a polymer A are dispersed into a solvent A to prepare a spinning internal liquid; on the other hand, a polymer B and a polymer C are dissolved in a solvent B to prepare a spinning external liquid; finally, the dioxin adsorption fiber membrane is prepared through a coaxial electrospinning method and a high-temperature carbonization process. The dioxin adsorption fiber membrane prepared by adopting the method has an adsorption rate of dioxin of more than 90%, and has a particle collection rate of 0.3 microns of more than 98%, and has a wide industrial application prospect. In addition, the fiber membrane prepared by adopting the method still has excellent dioxin adsorption effect and good mechanical strength after long-time use.

Description

Technical Field

[0001] This invention relates to environmental materials, and more specifically, to a method for preparing a dioxin-adsorbing fiber membrane. Background Technology

[0002] Dioxins are commonly generated during processes such as waste incineration, steel smelting, and papermaking. They are a common name for polychlorinated tricyclic aromatic hydrocarbons (PCTs), toxic chemicals. Dioxins are not a single substance, but a mixture of over 200 isomers and homologues, making them chemically very stable organic compounds that are difficult to eliminate. They can accumulate in the human and animal bodies, causing cell carcinogenesis, deformities, and even mutations. The presence of dioxins is extremely harmful to human health; therefore, controlling dioxins is necessary and urgent. Currently, dioxin control methods mainly include: strictly controlling the incineration of high-chlorine materials, adding inorganic inhibitors, and adsorption control technology. Adsorption control technology refers to filtering waste gas to adsorb and remove dioxin pollutants, and it is considered one of the most effective technologies for dioxin treatment in waste gas. Existing technologies also propose using fibrous membrane materials for adsorption treatment. Due to their high porosity and interconnected pore structure, fibrous membrane materials are ideal adsorption materials. Compared to traditional adsorbents, fibrous membrane materials have active sites located on the membrane surface or pore walls, which greatly increases the contact between the material and the adsorbed components, reduces reaction time, shortens the reaction process, and allows for control of reactor volume. Common methods for preparing fibrous membranes include stretching, template synthesis, phase separation, self-assembly, and electrospinning. Electrospinning is the only method that can continuously prepare nanoscale fibrous membranes.

[0003] However, existing fiber membrane materials still suffer from low dioxin capture rates in waste gases, making it difficult to meet the demands for dioxin capture and collection. Furthermore, with frequent and prolonged use, and increasing surface modification and pollution levels, fiber membrane materials inevitably experience shrinkage, agglomeration, and embrittlement, resulting in irreversible damage and making it difficult to maintain both excellent long-term adsorption performance and mechanical strength. Therefore, developing a high-performance fiber membrane with high dioxin filtration and adsorption efficiency is of paramount importance. Summary of the Invention

[0004] Therefore, in order to solve the problems of poor dioxin adsorption effect and decreased mechanical properties of fiber membrane materials after long-term use in the prior art, this invention provides a method for preparing a dioxin adsorption fiber membrane, the specific technical solution of which is as follows:

[0005] A method for preparing a dioxin-adsorbing fiber membrane includes the following steps:

[0006] Nitrogen-doped graphyne adsorbent was prepared by heat treatment of graphyne under a high-temperature ammonia atmosphere.

[0007] The nitrogen-doped graphylene adsorbent, nano-chalcogenide, and polymer A are dispersed in solvent A to prepare the spinning inner solution.

[0008] Polymer B and polymer C are dissolved in solvent B to prepare a spinning external solution;

[0009] Dioxin-adsorbing fiber membranes were prepared by coaxial electrospinning and high-temperature carbonization.

[0010] Furthermore, the heat treatment is as follows: Graphdiyne is heated to 600℃~750℃ in a tube furnace under an ammonia atmosphere and held at that temperature for 0.5h~3h.

[0011] Furthermore, the ammonia atmosphere is a mixture of ammonia and argon or a mixture of ammonia and nitrogen, and the volume ratio of ammonia to argon is (1:2) to (1:4).

[0012] Furthermore, the nano-chalcogenide includes one or a mixture of several of MoS2, MoSe2, MoTe2, SnSe, SnS, WS2, and WSe2.

[0013] Further, the polymer A includes one or a mixture of several of the following: polyvinyl alcohol, polyvinylpyrrolidone, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose, and urea.

[0014] Furthermore, solvent A includes one or a mixture of several of N,N-dimethylformamide, N-methylpyrrolidone, 1,4-dioxane, etc.

[0015] Furthermore, the mass ratio of the nitrogen-doped graphdiyne adsorbent to the nano-chalcogenide is (5:1) to (1:1).

[0016] Furthermore, the mass ratio of the total mass of the nitrogen-doped graphdiyne adsorbent and the nano-chalcogenide compound to the mass of the polymer A is (1:50) to (1:10).

[0017] Furthermore, the polymer B comprises one or a mixture of several of polyacrylonitrile, polyvinylidene fluoride, polyvinylpyrrolidone, and polyvinyl alcohol.

[0018] Further, the high-temperature carbonization treatment is as follows: the fiber membrane prepared by electrospinning is kept at 200℃~250℃ in an air atmosphere for 3h~5h, with a heating rate of 1℃ / min~5℃ / min; then, the fiber membrane is placed in an inert atmosphere at 700℃~900℃ for 2h~6h, with a heating rate of 5℃ / min~10℃ / min.

[0019] The above method involves heat-treating graphyne under a high-temperature ammonia atmosphere to prepare a nitrogen-doped graphyne adsorbent. Then, the nitrogen-doped graphyne adsorbent, nano-chalcogenides, and polymer A are dispersed in solvent A to prepare the spinning inner solution. Conversely, polymers B and C are dissolved in solvent B to prepare the spinning outer solution. Finally, a dioxin-adsorbing fiber membrane is prepared via coaxial electrospinning and a high-temperature carbonization process. The dioxin-adsorbing fiber membrane prepared using the method described in this application exhibits an adsorption rate of over 90% for dioxins and a capture rate of over 98% for 0.3-micron particles, demonstrating broad prospects for industrial application. Furthermore, the fiber membrane prepared in this application retains excellent dioxin adsorption performance even after prolonged use, while also possessing good mechanical strength. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process for preparing the dioxin-adsorbing fiber membrane in Example 1 of the present invention;

[0021] Figure 2 This is a schematic diagram showing the adsorption rate of dioxins by the dioxin-adsorbing fiber membrane prepared in Example 1 of the present invention.

[0022] Figure 3 This is a schematic diagram showing the adsorption rate of dioxins by the dioxin-adsorbing fiber membrane prepared in Example 2 of the present invention.

[0023] Figure 4 This is a schematic diagram showing the adsorption rate of dioxins by the dioxin-adsorbing fiber membrane prepared in Comparative Example 1. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] A method for preparing a dioxin-adsorbing fiber membrane according to one embodiment of the present invention includes the following steps:

[0027] Nitrogen-doped graphyne adsorbent was prepared by heat treatment of graphyne under a high-temperature ammonia atmosphere.

[0028] The nitrogen-doped graphylene adsorbent, nano-chalcogenide, and polymer A are dispersed in solvent A to prepare the spinning inner solution.

[0029] Polymer B and polymer C are dissolved in solvent B to prepare a spinning external solution;

[0030] Dioxin-adsorbing fiber membranes were prepared by coaxial electrospinning and high-temperature carbonization.

[0031] In one embodiment, the heat treatment is as follows: Graphdiyne is heated to 600°C to 750°C in a tube furnace under an ammonia atmosphere and held at that temperature for 0.5h to 3h.

[0032] In one embodiment, the ammonia atmosphere is a mixture of ammonia and argon or a mixture of ammonia and nitrogen, and the volume ratio of ammonia to argon is (1:2) to (1:4).

[0033] In one embodiment, the nano-chalcogenide includes one or a mixture of several of MoS2, MoSe2, MoTe2, SnSe, SnS, WS2, and WSe2.

[0034] In one embodiment, the size of the nano-chalcogenide is 50 nm to 800 nm.

[0035] In one embodiment, the nano-chalcogenide is in the form of two-dimensional sheets or particles.

[0036] In one embodiment, the polymer A includes one or a mixture of several of polyvinyl alcohol, polyvinylpyrrolidone, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose, and urea.

[0037] In one embodiment, solvent A includes one or a mixture of several of N,N-dimethylformamide, N-methylpyrrolidone, 1,4-dioxane, etc.

[0038] In one embodiment, the mass percentage of polymer A in the spinning solution is 8 wt% to 16 wt%.

[0039] In one embodiment, the mass ratio of the nitrogen-doped graphdiyne adsorbent to the nano-chalcogenide is (5:1) to (1:1).

[0040] In one embodiment, the total mass ratio of the nitrogen-doped graphdiyne adsorbent and the nano-chalcogenide to the polymer A is (1:50) to (1:10).

[0041] In one embodiment, the polymer B comprises one or a mixture of several of polyacrylonitrile, polyvinylidene fluoride, polyvinylpyrrolidone, and polyvinyl alcohol.

[0042] In one embodiment, the polyacrylonitrile has a molecular weight of 50,000; the polyvinylidene fluoride has a molecular weight of 8,000; the polyvinylpyrrolidone has a molecular weight of 40,000; and the polyvinyl alcohol has a molecular weight of 9,000 to 10,000.

[0043] In one embodiment, the solvent B comprises one or a mixture of several of N-methylpyrrolidone, dichloromethane, N,N-dimethylformamide, and 1,4-dioxane.

[0044] In one embodiment, polymer C accounts for 10% to 30% of the total mass of polymer B and polymer C.

[0045] In one embodiment, the solid content of the spinning solution is 8 wt% to 20 wt%.

[0046] In one embodiment, the coaxial electrospinning method yields a fiber membrane thickness greater than 4 mm.

[0047] In one embodiment, the high-temperature carbonization treatment is as follows: the fiber membrane prepared by electrospinning is kept at 200℃~250℃ in an air atmosphere for 3h~5h, with a heating rate of 1℃ / min~5℃ / min; then, the fiber membrane is placed in an inert atmosphere at 700℃~900℃ for 2h~6h, with a heating rate of 5℃ / min~10℃ / min.

[0048] The fiber membrane prepared in the above scheme has an adsorption rate of over 90% for dioxins and a capture rate of over 98% for 0.3-micron particles.

[0049] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments.

[0050] Example 1:

[0051] A method for preparing a dioxin-adsorbing fiber membrane includes the following steps:

[0052] S1: Add 100g of graphyne to a quartz boat, then place it in a quartz tube, and pass a mixture of ammonia and nitrogen gas through it. The gas flow rate is 140 sccm, and the flow rate ratio of nitrogen to ammonia is 2.5:1. After passing the gas for 10 min, raise the temperature to 700℃ at a heating rate of 10℃ / min and keep it at that temperature for 2.5 h to obtain nitrogen-doped graphyne.

[0053] S2: Dissolve 200g of polyacrylonitrile and 40g of urea in 1760g of N,N-dimethylformamide solution, then add 6g of nitrogen-doped graphylene obtained after S1 treatment and 2g of SnSe with a particle size of 100nm. After stirring for 8h, the spinning inner solution of the present invention is obtained for later use.

[0054] S3: Take 180g of polyacrylonitrile (molecular weight 150000) and 20g of polyvinylpyrrolidone (molecular weight 8000) and add them to 1800g of N,N-dimethylformamide solution, stir for 8h to obtain the spinning external solution of the present invention, for later use.

[0055] S4: Using the spinning inner liquid and spinning outer liquid prepared in S2 and S3 above as spinning liquids, a fiber membrane with a thickness of 8 mm is prepared by coaxial electrospinning under the conditions of 18KV voltage, inner liquid injection rate of 0.6mL / min, outer liquid injection rate of 1.2mL / min, and humidity below 18%.

[0056] S5: The fiber membrane obtained in S4 above is kept at 220°C in an air atmosphere for 3 hours with a heating rate of 1°C / min. After cooling, it is kept at 800°C in an inert atmosphere for 3 hours with a heating rate of 4°C / min. After natural cooling, the dioxin adsorption fiber membrane of the present invention is obtained.

[0057] The dioxin-adsorbing fiber membrane prepared in this embodiment was subjected to dioxin adsorption tests. The results showed that the adsorption rate for dioxins was over 93.1%, and the collection rate for 0.3-micron particles was also over 99.6%. After being reused 5 times, the adsorption rate for dioxins was still over 93.0%, and the collection rate for 0.3-micron particles was still over 99.5%. The membrane exhibited stable structure and maintained excellent mechanical properties and adsorption stability.

[0058] Example 2:

[0059] A method for preparing a dioxin-adsorbing fiber membrane includes the following steps:

[0060] S1: Take 100g of graphyne and add it to a quartz boat, then place it in a quartz tube and pass a mixture of ammonia and argon gas through it. The gas flow rate is 160sccm, and the flow ratio of argon to ammonia is 3:1. After passing the gas for 10min, raise the temperature to 650℃ at a heating rate of 5℃ / min and keep it at that temperature for 2h to obtain nitrogen-doped graphyne.

[0061] S2: Dissolve 200g of polyacrylonitrile in 1800g of N,N-dimethylformamide solution, then add 8g of nitrogen-doped graphylene obtained after S1 treatment and 2g of MoSe2 with a particle size of 200nm. After stirring for 8h, the spinning inner solution of the present invention is obtained for later use.

[0062] S3: Take 160g of polyacrylonitrile (molecular weight 150000) and 40g of polyvinyl alcohol (molecular weight 9000-10000) and add them to 1466.66g of N,N-dimethylformamide solution, stir for 8h to obtain the spinning external solution of the present invention, for later use;

[0063] S4: Using the spinning inner liquid and spinning outer liquid prepared in S2 and S3 above as spinning liquids, a fiber membrane with a thickness of 6 mm is prepared by coaxial electrospinning under the conditions of 18KV voltage, inner liquid injection rate of 0.8mL / min, outer liquid injection rate of 1.4mL / min, and humidity below 18%.

[0064] S5: The fiber membrane obtained in S4 above is kept at 230°C in an air atmosphere for 3 hours with a heating rate of 1.5°C / min. After cooling, it is kept at 800°C in an inert atmosphere for 3 hours with a heating rate of 5°C / min. After natural cooling, the dioxin adsorption fiber membrane of the present invention is obtained.

[0065] The dioxin adsorption fiber membrane prepared in Example 2 was subjected to a dioxin adsorption test. The results showed that the adsorption rate of dioxins was over 91.7%, and the collection rate of 0.3-micron particles was also over 99.2%. After being reused 5 times, the adsorption rate of dioxins was over 91.6%, and the collection rate of 0.3-micron particles was also over 99.0%. The structure was stable and it still had excellent mechanical properties and adsorption stability.

[0066] Example 3:

[0067] A method for preparing a dioxin-adsorbing fiber membrane includes the following steps:

[0068] S1: Add 100g of graphyne to a quartz boat, then place it in a quartz tube, and pass a mixture of ammonia and argon gas through it. The gas flow rate is 180sccm, and the flow ratio of argon to ammonia is 2:1. After passing the gas for 10min, raise the temperature to 700℃ at a heating rate of 3℃ / min and keep it at that temperature for 1.5h to obtain nitrogen-doped graphyne.

[0069] S2: Dissolve 200g of polyvinylidene fluoride in 1800g of N,N-dimethylformamide solution, then add 8.88g of nitrogen-doped graphylene obtained after S1 treatment and 4.44g of MoS2 with a particle size of 500nm. After stirring for 8h, the spinning inner solution of the present invention is obtained for later use.

[0070] S3: Take 160g of polyvinylidene fluoride (molecular weight 150,000) and 40g of polyacrylonitrile (molecular weight 50,000) and add them to 1800g of N,N-dimethylformamide solution. Stir for 8 hours to obtain the spinning external solution of the present invention for later use.

[0071] S4: Using the spinning inner liquid and spinning outer liquid prepared in S2 and S3 above as spinning liquids, a fiber membrane with a thickness of 6 mm is prepared by coaxial electrospinning under the conditions of 18KV voltage, inner liquid injection rate of 0.8mL / min, outer liquid injection rate of 1.4mL / min, and humidity below 18%.

[0072] S5: The fiber membrane obtained in S4 above is kept at 240°C in an air atmosphere for 2.5 hours with a heating rate of 1°C / min. After cooling, it is kept at 750°C in an inert atmosphere for 5 hours with a heating rate of 8°C / min. After natural cooling, the dioxin adsorption fiber membrane of the present invention is obtained.

[0073] The dioxin adsorption fiber membrane prepared in Example 3 was subjected to a dioxin adsorption test. The results showed that the adsorption rate of dioxins was over 90.6%, and the collection rate of 0.3-micron particles was also over 98.7%. After being reused 5 times, the adsorption rate of dioxins was over 90.5%, and the collection rate of 0.3-micron particles was also over 98.5%. The structure was stable and it still had excellent mechanical properties and adsorption stability.

[0074] Comparative Example 1:

[0075] A method for preparing a dioxin-adsorbing fiber membrane includes the following steps:

[0076] The difference between Comparative Example 1 and Example 1 is that the graphylene added in Comparative Example 1 was not treated under a high-temperature ammonia atmosphere, while the other processes were the same as in Example 1.

[0077] The dioxin adsorption fiber membrane prepared in Comparative Example 1 was subjected to an adsorption test for dioxins. The results showed that the adsorption rate for dioxins was 71.2% and the collection efficiency for 0.3 μm particles was 89.4%. After being reused 5 times, the adsorption rate for dioxins was 68.7% and the collection efficiency for 0.3 μm particles was 86.9%. The overall adsorption rate decreased slightly, but the structure remained stable and it had excellent mechanical properties.

[0078] Comparative Example 2:

[0079] A method for preparing a dioxin-adsorbing fiber membrane includes the following steps:

[0080] The difference between Comparative Example 2 and Example 1 is that no graphylene was added in Comparative Example 2, while the other processes were the same as in Example 1.

[0081] The dioxin adsorption fiber membrane prepared in Comparative Example 2 was subjected to a dioxin adsorption test. The results showed that the adsorption rate of dioxins was 63% and the collection efficiency of 0.3 μm particles was 86.5%. After being used repeatedly for 5 times, the adsorption rate of dioxins was 51% and the collection efficiency of 0.3 μm particles was 63.1%. It can be seen that the adsorption stability of dioxins is poor, the structure is poor, and the mechanical properties are 79% of those of Example 1 after 5 uses.

[0082] Comparative Example 3:

[0083] A method for preparing a dioxin-adsorbing fiber membrane includes the following steps:

[0084] The difference between Comparative Example 3 and Example 1 is that no nano-chalcogenide compound was added in Comparative Example 3, while the other processes were the same as in Example 1.

[0085] The dioxin adsorption fiber membrane prepared in Comparative Example 3 was subjected to a dioxin adsorption test. The results showed that the adsorption rate of dioxins was 68% and the collection efficiency of 0.3 μm particles was 85.2%. After repeated use 5 times, the adsorption rate of dioxins was 55% and the collection efficiency of 0.3 μm particles was 81.2%. It can be seen that the adsorption effect of dioxins deteriorated after repeated use. The structure was better and the mechanical properties were 82% of those of Example 1 after 5 uses.

[0086] Comparative Example 4:

[0087] A method for preparing a dioxin-adsorbing fiber membrane includes the following steps:

[0088] The difference between Comparative Example 4 and Example 1 is that no graphylene and nano-chalcogenide were added in Comparative Example 4, while the other processes were the same as in Example 1.

[0089] The dioxin adsorption fiber membrane prepared in Comparative Example 4 was subjected to a dioxin adsorption test. The results showed that the adsorption rate of dioxins was 37% and the collection efficiency of 0.3 μm particles was 71.6%. After being used 5 times, the adsorption rate of dioxins was 29.1% and the collection efficiency of 0.3 μm particles was 63.7%. The structure was poor and the mechanical properties were 64% of those of the example after 5 uses.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for producing a dioxin adsorbing fiber film, characterized by, The method comprises the following steps: The graphite yne is heated to 600-750 DEG C in an ammonia atmosphere in a tube furnace for 0.5-3 h, the ammonia atmosphere is a mixture of ammonia and argon or a mixture of ammonia and nitrogen, the volume ratio of ammonia to argon is (1:2)-(1:4), the volume ratio of ammonia to argon is (1:2)-(1:4), and a nitrogen-doped graphite yne adsorbent is prepared; The nitrogen-doped graphite yne adsorbent, nano-sulfur compound and polymer A are dispersed in solvent A to prepare a spinning internal solution; the mass ratio of the nitrogen-doped graphite yne adsorbent to the nano-sulfur compound is (5:1)-(1:1); and the mass ratio of the total mass of the nitrogen-doped graphite yne adsorbent and nano-sulfur compound to the polymer A is (1:50)-(1:10). Polymer B and polymer C are dissolved in solvent B to prepare a spinning external solution; the polymer C is polyvinylpyrrolidone or polyvinyl alcohol; The fiber membrane prepared by the coaxial electrospinning method is treated by high-temperature carbonization, the high-temperature carbonization is that the fiber membrane is placed in an air atmosphere at 200-250 DEG C for 3-5 h at a heating rate of 1-5 DEG C / min, and then the fiber membrane is placed in an inert atmosphere at 700-900 DEG C for 2-6 h at a heating rate of 5-10 DEG C / min, and a dioxin adsorption fiber membrane is prepared.

2. The production method according to claim 1, characterized by, The nano-sulfur compound includes one or a mixture of several of MoS2, MoSe2, MoTe2, SnSe, SnS, WS2 and WSe2.

3. The preparation method according to claim 1, characterized in that, The polymer A includes one or a mixture of several of polyvinyl alcohol, polyvinylpyrrolidone, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, carboxymethyl cellulose and urea. The polymer B includes one or a mixture of several of polyacrylonitrile, polyvinylidene fluoride, polyvinylpyrrolidone and polyvinyl alcohol. The molecular weight of the polyacrylonitrile is 50000, the molecular weight of the polyvinylidene fluoride is 8000, the molecular weight of the polyvinylpyrrolidone is 40000, and the molecular weight of the polyvinyl alcohol is 9000-10000.

4. The production method according to claim 1, characterized by, The solvent A includes one or a mixture of several of N,N-dimethylformamide, N-methylpyrrolidone and 1,4-dioxane.

5. The method of claim 1, wherein, The polymer B includes one or a mixture of several of polyacrylonitrile, polyvinylidene fluoride, polyvinylpyrrolidone and polyvinyl alcohol.

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