Highly permeable nanoscale silicon carbide ceramic flat sheet membrane and method of making same
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG JIANMO TECH CO LTD
- Filing Date
- 2026-04-08
- Publication Date
- 2026-07-07
AI Technical Summary
The silicon carbide particles exhibit dispersion issues during preparation, leading to uneven pore size distribution and reduced connectivity in the membrane, which in turn affects the membrane's high-throughput performance and separation stability.
A dispersion sol was prepared by reacting bacterial cellulose with epoxy silane and polyaspartic acid, followed by mixing with polyacrylonitrile dispersion and zinc ion aqueous solution. The uniform dispersion of silicon carbide particles was achieved through hydrogen bonding and dipole-dipole interactions, and a network of interconnected channels was formed during sintering.
It improves the porosity and flux of silicon carbide ceramic flat sheet membranes, reduces the risk of clogging, and enhances the membrane's antifouling resistance and service life.
Smart Images
Figure CN121972027B_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of ceramic membrane technology, and in particular relates to a high-permeability nanoscale silicon carbide ceramic flat sheet membrane and its preparation method. Background Technology
[0002] Membrane separation technology is one of the core technologies in modern separation science. Ceramic flat-sheet membranes, as an important branch of inorganic membranes, have gained widespread attention in numerous industrial fields due to their regular flat-sheet configuration, excellent mechanical strength, high-temperature resistance, chemical corrosion resistance, and ease of modular integration. Compared to other ceramic membrane configurations, ceramic flat-sheet membranes offer higher packing density and easier assembly, effectively improving separation efficiency and adapting to separation scenarios of different scales, making them a key carrier for promoting the large-scale application of membrane separation technology.
[0003] Silicon carbide, as a high-performance inorganic ceramic material, possesses excellent chemical inertness, mechanical strength, and thermal stability, making it an ideal raw material for preparing high-performance ceramic flat-sheet membranes. Leveraging the high specific surface area of silicon carbide particles, membrane structures with uniform pore size and good connectivity can be constructed, significantly improving membrane permeability and separation efficiency, thus meeting the demands for efficient separation in various fields.
[0004] Currently, high-permeability nano-silicon carbide ceramic flat sheet membranes have shown broad application prospects in environmental wastewater treatment, chemical fluid separation, and gas purification. However, with the continuous improvement of separation requirements, higher demands are being placed on the separation performance of silicon carbide flat sheet membranes. During the preparation process of silicon carbide flat sheet membranes, we have discovered the dispersion problem of small silicon carbide particles, which leads to a series of chain reactions. Due to their large specific surface area and high surface energy, silicon carbide particles are prone to agglomeration, making it difficult to achieve uniform dispersion in the preparation system. This results in uneven pore size distribution and poor connectivity of the membrane layer, directly affecting the high-flux performance and separation stability of the membrane. It also limits the yield and service life of the membrane material. Therefore, it is essential to prepare a silicon carbide flat sheet membrane with high water flux. Summary of the Invention
[0005] To address the aforementioned issues and further resolve the silicon carbide dispersion problem, thereby increasing the water flux of the flat sheet membrane, this application provides a high-permeability nanoscale silicon carbide ceramic flat sheet membrane and its preparation method.
[0006] This application first provides a method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane, comprising the following steps:
[0007] 1) Mix silicon carbide and additives, then add dispersing sol and deionized water to obtain mud;
[0008] The dispersion sol is prepared by reacting bacterial cellulose with epoxy silane and polyaspartic acid, and then mixing it with polyacrylonitrile dispersion and zinc ion aqueous solution.
[0009] 2) After aging, the clay is extruded, aged a second time, and then extruded into shape to obtain the original body.
[0010] 3) The original substrate is sintered and impregnated with a coating solution to obtain a high-permeability nanoscale silicon carbide ceramic flat sheet membrane.
[0011] Furthermore, the preparation method of the dispersible sol in step 1) includes the following steps:
[0012] S1: Bacterial cellulose and deionized water are mixed, then epoxy silane and polyaspartic acid are added, stirred, and then a catalyst is added to carry out the polymerization reaction. After cooling, the base solution is obtained.
[0013] S2: Add polyacrylonitrile powder to sodium thiocyanate aqueous solution, stir to obtain polyacrylonitrile solution, then add deionized water for precipitation, filter, wash, redisperse the solid components in deionized water, and shear at high speed to obtain polyacrylonitrile dispersion.
[0014] S3: Mix the base solution with the polyacrylonitrile dispersion, then add the zinc acetate aqueous solution and continue stirring to obtain the dispersion sol.
[0015] Furthermore, in step S1, the mass ratio of bacterial cellulose, deionized water and polyaspartic acid is 1:(200-220):(1.6-2).
[0016] Furthermore, in step S3, the concentration of the zinc acetate aqueous solution is 0.3-0.5 mol / L.
[0017] Furthermore, in step 1), the mass fraction of silicon carbide is 100-120 parts, the mass fraction of the additive is 8-10 parts, the mass fraction of the dispersing sol is 2-4 parts, and the mass fraction of deionized water is 10-15 parts.
[0018] Furthermore, in step 1), the additives include kaolin, methylcellulose, and boron carbide.
[0019] Furthermore, in step 2), the aging temperature is 25-30℃ and the relative humidity is ≥85%.
[0020] Furthermore, the sintering temperature in step 3) is 1600-1750℃.
[0021] Furthermore, in step 3), the coating liquid comprises silicon carbide, polyethylene glycol, and sodium hexametaphosphate.
[0022] This application also provides a high-permeability nanoscale silicon carbide ceramic flat sheet membrane, which is prepared by the above-described method.
[0023] Compared with the prior art, this application has the following beneficial effects:
[0024] 1. Bacterial cellulose forms a three-dimensional nano-network to construct a micro-nano space, while the abundant polar functional groups on the polyaspartic acid segments adsorb onto the surface of silicon carbide particles through hydrogen bonds and dipole-dipole interactions, achieving uniform dispersion of silicon carbide particles in the organic network. During the sintering process, a highly interconnected, low-torsional-degree pore network is formed, improving the porosity and flux of the flat sheet membrane.
[0025] 2. Zinc ions bridge the two polymers through coordination, improving the stability of the dispersed sol and ensuring the stability of the pore network during sintering. Meanwhile, the gas released by the high-temperature thermal decomposition of polyacrylonitrile creates more interconnected pores within the framework formed by the bacterial cellulose network, reducing the risk of clogging and further modifying the silicon carbide sintering process, giving the flat sheet membrane higher porosity and antifouling properties. Attached Figure Description
[0026] Figure 1 The images shown are cross-sectional SEM images of the flat sheet membranes of Example 1 and Comparative Examples 1-2 of this application. Detailed Implementation
[0027] To make the inventive objectives, technical solutions, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments, clearly and completely describing the technical solutions in the embodiments of this application. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0028] 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 application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0029] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.
[0030] The terms "preferred," "more preferably," "better," and "even better" used in this application refer to embodiments of this application that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, "preferred," "more preferably," "better," and "even better" are merely descriptions of implementations or embodiments with better effects, but do not constitute a limitation on the scope of protection of this application.
[0031] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.
[0032] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.
[0033] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.
[0034] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.
[0035] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.
[0036] In this application, room temperature refers to 0-40°C, including but not limited to 10-40°C, or further to 20-30°C.
[0037] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.
[0038] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.
[0039] Preparation Example 1
[0040] Mix 5g sodium hexametaphosphate and 250g deionized water, add 50g silicon carbide (average particle size 0.4μm), stir and mix for 10min, then add 55mL polyethylene glycol (PEG4000), and continue stirring for 40min to obtain the coating solution.
[0041] Preparation Example 2
[0042] Weigh 2g of polyacrylonitrile powder and place it in a beaker. Add 100g of 50wt% sodium thiocyanate aqueous solution to the beaker, heat to 85℃, and stir at 500rpm for 2h. Then add 0.5g of polyvinylpyrrolidone K30 and continue stirring for 30min to obtain a mixture. Then, at a stirring speed of 800rpm, add the mixture to 10 times its volume of deionized water at a rate of 1mL / min. After the addition is complete, continue stirring for 30min. Filter and retain the solid component. Redisperse the washed solid component in 110g of deionized water and perform high-speed shearing at 12000rpm for 10min and ultrasonic dispersion at 300W for 20min in sequence to obtain a polyacrylonitrile dispersion.
[0043] Example 1
[0044] The preparation method of the high-permeability nanoscale silicon carbide ceramic flat sheet membrane in this embodiment is as follows:
[0045] 1) Weigh 1 kg of silicon carbide (silicon carbide with an average particle size of 5 μm and silicon carbide with an average particle size of 2 μm weighed at a mass ratio of 15:1), 40 g of kaolin, 15 g of methyl cellulose, 15 g of alumina, and 10 g of boron carbide and place them in a high-speed mixer for dry mixing at a speed of 300 rpm for 10 min. After mixing, transfer the mixed dry material to a twin-screw extruder, add 20 g of dispersing sol and 100 g of deionized water, adjust the speed to 50 rpm, and the meshing time to 30 min to obtain mud.
[0046] 2) Place the clay in a constant temperature and humidity sealed aging chamber for aging treatment. The temperature is 25℃, the relative humidity is ≥85%, and the aging time is 24h. After aging, the clay is kneaded again for 10min in a kneader, and then extruded into shape by an extruder. The extruded clay blocks are placed in a constant temperature and humidity sealed aging chamber for secondary aging treatment. The temperature is 25℃, the humidity is ≥85%, and the time is 24h. The clay blocks after secondary aging are put into a flat ceramic film extruder and extruded into shape using a flat die head. They are dried at room temperature for two days to obtain the original body.
[0047] 3) The original substrate was placed in a high-temperature sintering furnace for sintering treatment. The temperature was first raised from room temperature to 600℃ at a heating rate of 5℃ / min, then raised to 1200℃ at a heating rate of 10℃ / min, and finally raised to 1600℃ at a heating rate of 15℃ / min. The temperature was maintained at this temperature for 4 hours. After cooling to room temperature, the substrate was immersed in the coating solution for 50 seconds. It was then removed, dried at 40℃ for two days, and then sintered at 1100℃ for 30 minutes to obtain a high-transparency nanoscale silicon carbide ceramic flat sheet membrane.
[0048] The method for preparing the dispersion sol in this embodiment is as follows:
[0049] S1: Take 3g of bacterial cellulose and put it into a flask. Add 600g of deionized water, sonicate at 300W and 40kHz for 30min, stir at 1000rpm for 40min, add hydrochloric acid to adjust the pH of the system to 5.5, then heat the system to 75℃, and add 1.2g of KH560 dropwise to the system. After stirring for 2h, add a mixed solution consisting of 4.8g of polyaspartic acid (Wm=4000) and 240g of deionized water, stir for 10min, then add 1 drop of triethylamine, and stir at a constant temperature for 4h to obtain the base solution.
[0050] S2: Add the polyacrylonitrile dispersion to the base solution and stir at 400 rpm for 20 min. Then, homogenize at 10,000 rpm for 8 min in a high-speed homogenizer. While stirring at 300 rpm, add 1 g of 0.5 mol / L zinc acetate aqueous solution dropwise to the homogenized mixture. After the addition is complete, continue stirring for 15 min. Stir at 150 rpm for 60 min at room temperature to obtain the dispersion sol.
[0051] The coating solution in this embodiment was prepared in Preparation Example 1.
[0052] The polyacrylonitrile dispersion in this embodiment was prepared in Preparation Example 2.
[0053] Example 2
[0054] The preparation method of the high-permeability nanoscale silicon carbide ceramic flat sheet membrane in this embodiment is as follows:
[0055] 1) Weigh 1.2 kg of silicon carbide (silicon carbide with an average particle size of 5 μm and silicon carbide with an average particle size of 2 μm weighed at a mass ratio of 15:1), 43 g of kaolin, 25 g of methyl cellulose, 12 g of alumina, and 20 g of boron carbide and place them in a high-speed mixer for dry mixing at a speed of 400 rpm for 10 min. After mixing, transfer the mixed dry material to a twin-screw extruder, add 40 g of dispersing sol and 150 g of deionized water, adjust the speed to 60 rpm, and the meshing time to 30 min to obtain mud.
[0056] 2) Place the clay in a constant temperature and humidity sealed aging chamber for aging treatment. The temperature is 30℃, the relative humidity is ≥85%, and the aging time is 24h. After aging, the clay is kneaded in a kneader for 10min, and then extruded into shape by an extruder. The extruded clay blocks are placed in a constant temperature and humidity sealed aging chamber for secondary aging treatment. The temperature is 30℃, the humidity is ≥85%, and the time is 24h. The clay blocks after secondary aging are put into a flat ceramic film extruder and extruded into shape using a flat die head. They are dried at room temperature for two days to obtain the original body.
[0057] 3) The original substrate was placed in a high-temperature sintering furnace for sintering treatment. The temperature was first raised from room temperature to 600℃ at a heating rate of 10℃ / min, then raised to 1200℃ at a heating rate of 15℃ / min, and finally raised to 1650℃ at a heating rate of 20℃ / min. The temperature was maintained at this temperature for 8 hours, then immersed in the coating solution for 50 seconds, removed, dried at 40℃ for two days, and then sintered at 1100℃ for 30 minutes to obtain a high-transparency nanoscale silicon carbide ceramic flat sheet membrane.
[0058] The method for preparing the dispersion sol in this embodiment is as follows:
[0059] S1: Take 3g of bacterial cellulose and put it into a flask. Add 660g of deionized water, sonicate at 300W and 40kHz for 30min, stir at 1000rpm for 40min, add hydrochloric acid to adjust the pH of the system to 5.5, then heat the system to 75℃, and add 1.5g of KH560 dropwise to the system. After stirring for 2h, add a mixed solution consisting of 6g of polyaspartic acid (Wm=4000) and 300g of deionized water, stir for 10min, then add 1 drop of triethylamine, and stir at a constant temperature for 4h to obtain the base solution.
[0060] S2: Add the polyacrylonitrile dispersion to the base solution and stir at 400 rpm for 20 min. Then, homogenize at 10,000 rpm for 8 min in a high-speed homogenizer. While stirring at 300 rpm, add 1.7 g of 0.3 mol / L zinc acetate aqueous solution dropwise to the homogenized mixture. After the addition is complete, continue stirring for 15 min. Stir at 150 rpm for 60 min at room temperature to obtain the dispersion sol.
[0061] The coating solution in this embodiment was prepared in Preparation Example 1.
[0062] The polyacrylonitrile dispersion in this embodiment was prepared in Preparation Example 2.
[0063] Example 3
[0064] The preparation method of the high-permeability nanoscale silicon carbide ceramic flat sheet membrane in this embodiment is as follows:
[0065] 1) Weigh 1.1 kg of silicon carbide (silicon carbide with an average particle size of 5 μm and silicon carbide with an average particle size of 1 μm weighed at a mass ratio of 15:1), 42 g of kaolin, 20 g of methyl cellulose, 8 g of alumina, and 15 g of boron carbide and place them in a high-speed mixer for dry mixing at a speed of 300 rpm for 20 min. After mixing, transfer the mixed dry material to a twin-screw extruder, add 30 g of dispersing sol and 120 g of deionized water, adjust the speed to 50 rpm, and the meshing time to 30 min to obtain mud.
[0066] 2) Place the clay in a constant temperature and humidity sealed aging chamber for aging treatment. The temperature is 28℃, the relative humidity is ≥85%, and the aging time is 24h. After aging, the clay is kneaded in a kneader for 10min, and then extruded into shape by an extruder. The extruded clay blocks are placed in a constant temperature and humidity sealed aging chamber for secondary aging treatment. The temperature is 30℃, the humidity is ≥85%, and the time is 24h. The clay blocks after secondary aging are put into a flat ceramic film extruder and extruded into shape using a flat die head. They are dried at room temperature for two days to obtain the original body.
[0067] 3) The original substrate was placed in a high-temperature sintering furnace for sintering treatment. The temperature was first raised from room temperature to 600℃ at a heating rate of 5℃ / min, then raised to 1200℃ at a heating rate of 15℃ / min, and finally raised to 1600℃ at a heating rate of 15℃ / min. The temperature was maintained at this temperature for 4 hours, then immersed in the coating solution for 50 seconds, removed, dried at 40℃ for two days, and then sintered at 1100℃ for 30 minutes to obtain a high-permeability nanoscale silicon carbide ceramic flat sheet membrane.
[0068] The method for preparing the dispersion sol in this embodiment is as follows:
[0069] S1: Take 3g of bacterial cellulose and put it into a flask. Add 600g of deionized water, sonicate at 300W and 40kHz for 30min, stir at 1000rpm for 40min, add hydrochloric acid to adjust the pH of the system to 5.5, then heat the system to 75℃, and add 1.2g of KH560 dropwise to the system. After stirring for 2h, add a mixed solution consisting of 5g of polyaspartic acid (Wm=4000) and 240g of deionized water, stir for 10min, then add 1 drop of triethylamine, and stir at a constant temperature for 4h to obtain the base solution.
[0070] S2: Add the polyacrylonitrile dispersion to the base solution and stir at 400 rpm for 20 min. Then, homogenize at 10,000 rpm for 10 min in a high-speed homogenizer. While stirring at 300 rpm, add 1.3 g of 0.4 mol / L zinc acetate aqueous solution dropwise to the homogenized mixture. After the addition is complete, continue stirring for 15 min. Stir at 150 rpm for 60 min at room temperature to obtain the dispersion sol.
[0071] The coating solution in this embodiment was prepared in Preparation Example 1.
[0072] The polyacrylonitrile dispersion in this embodiment was prepared in Preparation Example 2.
[0073] Comparative Example 1
[0074] The difference between this comparative example and Example 1 is that polyaspartic acid was not added during the preparation of the dispersion sol.
[0075] The remaining steps are the same as in Example 1.
[0076] Comparative Example 2
[0077] The difference between this comparative example and Example 1 is that no polyacrylonitrile dispersion was added during the preparation of the dispersible sol.
[0078] The remaining steps are the same as in Example 1.
[0079] Performance testing
[0080] 1. Pure water flux test (dead-end filtration method)
[0081] At 25℃, the ceramic membrane was completely immersed in deionized water, first sonicated at 30kHz for 8 minutes, then soaked for 25 minutes, and finally filtered with deionized water. After the outflowing water stabilized, it was then processed according to the formula. Pure water flux was calculated. The test results for the flat sheet membranes of Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.
[0082] Where J is the pure water flux (L·m -2 ·h -1 ·bar -1 V represents the outflow rate (L), and A represents the effective surface area of the membrane (m²). 2 ), t is the filtration time (h), and P is the transmembrane pressure (bar).
[0083] 2. Porosity test (Archimedes drainage method)
[0084] After drying the ceramic membrane in an oven, its mass is measured. The dried sample is then soaked in deionized water for 24 hours. Next, the sample is suspended in a special basket and completely submerged in the deionized water, ensuring it does not contact the container's inner wall or bottom. The underwater suspended mass of the sample is then measured. After removing the sample, a small amount of free water will adhere to the membrane surface. Excess water should be gently wiped away with pre-soaked multi-layered gauze. The total wet mass of the sample is then measured. Finally, the final mass is determined according to the formula... Porosity was calculated. The test results for the flat sheet membranes of Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.
[0085] Where m1 is the mass of the sample after drying (g), m2 is the underwater mass of the sample when it is suspended in the basket (g), and m3 is the wet mass of the sample after wiping off the surface moisture (g).
[0086] 3. The cross-sections of the flat sheet membranes of Example 1 and Comparative Examples 1-2 were observed using a scanning electron microscope. The results are as follows: Figure 1 As shown.
[0087] Table 1. Performance test results of flat sheet membranes
[0088]
[0089] Analysis of Examples 1-3 and Comparative Examples 1-2, in conjunction with Table 1 and Figure 1 In the preparation of flat sheet membranes, the addition of self-made dispersing sol can improve the water flux and porosity of the flat sheet membrane. By comparing the examples with the comparative examples, the presence of polyaspartic acid and polyacrylonitrile dispersion in the dispersing sol has a significant promoting effect on improving the water flux and porosity of the flat sheet membrane.
[0090] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane, characterized in that: Includes the following steps: 1) Mix silicon carbide and additives, then add dispersing sol and deionized water to obtain mud; The dispersion sol is prepared by reacting bacterial cellulose with epoxy silane and polyaspartic acid, and then mixing it with polyacrylonitrile dispersion and zinc ion aqueous solution. 2) After aging, the clay is extruded, aged a second time, and then extruded into shape to obtain the original body. 3) The original substrate is sintered and impregnated with a coating solution to obtain a high-permeability nanoscale silicon carbide ceramic flat sheet membrane.
2. The method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane according to claim 1, characterized in that: The preparation method of the dispersion sol in step 1) includes the following steps: S1: Bacterial cellulose and deionized water are mixed, then epoxy silane and polyaspartic acid are added, stirred, and then a catalyst is added to carry out the polymerization reaction. After cooling, the base solution is obtained. S2: Add polyacrylonitrile powder to sodium thiocyanate aqueous solution, stir to obtain polyacrylonitrile solution, then add deionized water for precipitation, filter, wash, redisperse the solid components in deionized water, and shear at high speed to obtain polyacrylonitrile dispersion. S3: Mix the base solution with the polyacrylonitrile dispersion, then add the zinc acetate aqueous solution and continue stirring to obtain the dispersion sol.
3. The method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane according to claim 2, characterized in that: In step S1, the mass ratio of bacterial cellulose, deionized water and polyaspartic acid is 1:(200-220):(1.6-2).
4. The method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane according to claim 2, characterized in that: In step S3, the concentration of the zinc acetate aqueous solution is 0.3-0.5 mol / L.
5. The method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane according to claim 2, characterized in that: In step 1), the mass fraction of silicon carbide is 100-120 parts, the mass fraction of the additive is 8-10 parts, the mass fraction of the dispersing sol is 2-4 parts, and the mass fraction of deionized water is 10-15 parts.
6. The method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane according to claim 1, characterized in that: In step 1), the additives include kaolin, methylcellulose, boron carbide, and alumina.
7. The method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane according to claim 1, characterized in that: In step 2), the aging temperature is 25-30℃ and the relative humidity is ≥85%.
8. The method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane according to claim 1, characterized in that: The sintering temperature in step 3) is 1600-1750℃.
9. The method for preparing a high-permeability nanoscale silicon carbide ceramic flat sheet membrane according to claim 1, characterized in that: In step 3), the coating solution comprises silicon carbide, polyethylene glycol, and sodium hexametaphosphate.
10. A high-permeability nanoscale silicon carbide ceramic flat sheet membrane, characterized in that: It is prepared by the method described in any one of claims 1-9.