Silicon carbide ceramic membrane with good pollution resistance and preparation method thereof

Abstract

The invention belongs to the technical field of ceramic membranes, and particularly relates to a silicon carbide ceramic membrane with good pollution resistance and a preparation method of the silicon carbide ceramic membrane. The silicon carbide support is prepared from the following raw materials in parts by weight: 80-100 parts of silicon carbide, 3-7 parts of a sintering aid, 5-10 parts of zirconium oxide whiskers, 5-10 parts of a first binder and 40-50 parts of deionized water; the coating layer is prepared from the following raw materials in parts by weight: 50-70 parts of modified silicon carbide micro powder, 4-8 parts of a second binder and 40-60 parts of deionized water. The prepared silicon carbide ceramic membrane with good pollution resistance has excellent antibacterial performance and filtering effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic membranes, and particularly relates to a silicon carbide ceramic membrane with excellent anti-pollution performance and a preparation method thereof. Background Art

[0002] Ceramic membrane separation technology is an efficient and energy-saving separation method, which is widely used in many fields such as chemical industry, petroleum and petrochemical industry, biochemistry, food, electronics, and medicine. Currently, common ceramic membrane materials on the market include alumina, titanium oxide, silicon oxide, zirconium oxide, and silicon carbide, etc. Among them, silicon carbide ceramic membranes show great application potential in industrial separation and water treatment fields due to their advantages such as high temperature resistance, thermal shock resistance, high mechanical strength, strong hydrophilicity, uniform pore size distribution, high chemical stability, and strong cleanability.

[0003] Patent CN115430297A discloses a silicon carbide ceramic membrane for heavy metal wastewater treatment and a production method thereof. The production method of the silicon carbide ceramic membrane for heavy metal wastewater treatment consists of the following steps in sequence: preparing a support membrane layer, preparing an intermediate body, and preparing a silicon carbide ceramic membrane. The silicon carbide ceramic membrane for heavy metal wastewater treatment of this invention can effectively improve the film-forming integrity and uniformity of the filtration membrane layer on the outer surface of the support membrane layer while ensuring good flexural strength and filtration performance. The filtration pressure drop at different positions of the silicon carbide ceramic membrane and the water flux per unit membrane area are uniform, and it can maintain good long-term filtration performance. Patent CN115385714B discloses a silicon carbide ceramic membrane suitable for sponge cities and a preparation method thereof. The silicon carbide ceramic membrane suitable for sponge cities is prepared by the following method: first, preparing a slurry by mixing silicon carbide powder, sintering aids, and water, then preparing silicon carbide spherical powder by spray drying, extrusion molding of the silicon carbide support: mixing the silicon carbide spherical powder obtained by spray drying with polyethylene oxide, and then extruding the mixture after aging to obtain a green silicon carbide support, sintering to obtain a silicon carbide support, preparing a separation layer slurry by mixing silicon carbide fine powder, dispersant, and water, and then adding a surface modifier to the separation layer slurry, mixing evenly to make a coating material, and high-temperature sintering to prepare a silicon carbide ceramic membrane suitable for sponge cities. This invention can effectively solve the problems of urban black and odorous water bodies and sewage treatment, strengthen the construction of the water treatment system, prevent and eliminate the continuous generation of class V black and odorous water bodies, realize waterlogging prevention and control, and soil and water conservation, laying a solid foundation for building a comprehensive sponge city. However, the above two kinds of silicon carbide ceramic membranes may not have antibacterial properties.

[0004] Therefore, there is an urgent need in the market for a silicon carbide ceramic membrane with antibacterial properties and excellent anti-pollution performance. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to obtain a silicon carbide ceramic membrane with good filtering effect, antibacterial performance and excellent anti-pollution property.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] On the one hand, the present invention provides a silicon carbide ceramic membrane with excellent anti-pollution property, which comprises a silicon carbide support and a coating layer; to prepare the silicon carbide support, calculated by weight, the following raw materials are included: 80-100 parts of silicon carbide, 3-7 parts of sintering aid, 5-10 parts of zirconia whiskers, 5-10 parts of the first binder, 40-50 parts of deionized water; to prepare the coating layer, calculated by weight, the following raw materials are included: 50-70 parts of modified silicon carbide micropowder, 4-8 parts of the second binder, 40-60 parts of deionized water.

[0008] In this application, silicon carbide, sintering aid, carbon fiber are mixed with binder and deionized water, and then obtained the silicon carbide support through ball milling, extrusion molding and sintering. Then, the coating solution prepared from modified silicon carbide micropowder, binder and deionized water is coated on the porous zirconia ceramic support, and then calcined, so that the obtained silicon carbide ceramic membrane with excellent anti-pollution property has excellent antibacterial property and filtering effect.

[0009] In some embodiments, the preparation method of the modified silicon carbide micropowder comprises the following steps: adding copper nitrate trihydrate into deionized water, stirring at room temperature for 15-25 min, adding citric acid and silicon carbide micropowder, stirring at 700-900 rpm for 20-28 h, adding 20-28 wt% ammonia water to adjust the pH to 7-8, and drying at 80-120 °C to obtain the modified silicon carbide micropowder.

[0010] In this application, by using copper nitrate trihydrate, citric acid, and ammonia water to modify silicon carbide micropowder, on the one hand, the antibacterial property and filtration effect of the silicon carbide ceramic membrane can be improved, making its anti-fouling performance more perfect. This may be because after copper ions are introduced into the ceramic membrane, they can bind to the negatively charged groups on the bacterial cell membrane during the filtration process, destroying the integrity of the cell membrane and thus causing the bacteria to die. And copper ions can catalyze the generation of reactive oxygen species with strong oxidizing properties, which can damage the cell membrane, proteins, and DNA of bacteria, thereby killing the bacteria. On the other hand, copper nitrate trihydrate, citric acid, and ammonia water can react to form ions such as tetraamminecopper, which are loaded on the silicon carbide micropowder and can produce strong hydrogen bond interactions with hydroxyl groups, carboxyl groups, etc. on water or the binder, facilitating the dispersion of the silicon carbide micropowder in the coating solution, making the pore size distribution of the ceramic membrane narrower, and thus being conducive to improving the filtration effect of the ceramic membrane. In addition, during the preparation process of the coating layer, tetraamminecopper ions are sintered to form copper oxide, which can form a liquid phase at a lower temperature, fill the pores between silicon carbide particles, promote the rearrangement and sintering of the particles, and is conducive to improving the denseness of the ceramic membrane and enhancing the filtration accuracy, and thus is conducive to improving the anti-fouling performance of the ceramic membrane.

[0011] In some embodiments, the particle size of the silicon carbide micropowder is 3000 - 6000 mesh.

[0012] In some embodiments, the mass ratio of copper nitrate trihydrate, citric acid, and silicon carbide micropowder is (0.1 - 0.4):(0.25 - 0.65):1.

[0013] In this invention, by defining the mass ratio of copper nitrate trihydrate, citric acid, and silicon carbide micropowder, the anti-fouling property of the modified silicon carbide ceramic membrane is increased. At this ratio, it can avoid the blockage of the pores between silicon carbide particles by copper oxide, reducing the number of pores, and thus ensuring the filtration effect of the silicon carbide ceramic membrane.

[0014] In some embodiments, the preparation method of the second binder includes the following steps: adding acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and 2-hydroxyethyl methacrylate into deionized water, stirring at 45 - 55 °C for 20 - 30 min, adding an initiator, raising the temperature to 65 - 75 °C and reacting for 3 - 5 h, adding a 45 - 55 wt% sodium hydroxide aqueous solution to adjust the pH to 7 - 8, and drying to obtain the second binder.

[0015] In this application, a binder is synthesized by using 2-acrylamide-2-methylpropanesulfonic acid and 2-hydroxyethyl methacrylate to modify sodium polyacrylate. When used to prepare ceramic membranes, it can further improve the anti-fouling performance of the ceramic membranes. This may be because the sulfonic acid groups on this binder can complex with copper ions, while the hydroxyl and amino groups can form strong hydrogen bonds with the modified ceramic micropowders, making the modified ceramic micropowders more easily dispersed in the coating solution, reducing the pore size of the ceramic membranes and increasing the filtration accuracy, thereby facilitating the improvement of the filtration effect of the ceramic membranes.

[0016] In some embodiments, the preparation method of the initiator comprises the following steps: Ammonium persulfate and mercaptoacetic acid are added to deionized water, and the mass ratio of the three is (0.05 - 0.15):(0.1 - 0.4):1. Stir at room temperature for 20 - 30 min to obtain the initiator.

[0017] This application discovers that by preparing the initiator with ammonium persulfate and mercaptoacetic acid together, not only can the preparation efficiency of the second binder be improved, but also the anti-pollution performance of the silicon carbide ceramic membrane can be enhanced. This may be because mercaptoacetic acid has reducibility, which can prevent the oxidation and decomposition of copper tetraammine and other ions on the surface of the modified silicon carbide micropowders during the drying process, facilitating the improvement of the dispersibility of the modified silicon carbide micropowders and thus enhancing the anti-fouling property of the silicon carbide ceramic membrane.

[0018] In some embodiments, the mass ratio of acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and 2-hydroxyethyl methacrylate is 1:(0.1 - 0.4):(0.1 - 0.4).

[0019] The chain segment contents of 2-acrylamide-2-methylpropanesulfonic acid and 2-hydroxyethyl methacrylate affect the hydrophilicity of the second binder. By limiting the ratio of acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and 2-hydroxyethyl methacrylate in this application, the second binder can have good hydrophilicity while introducing more sulfonic acid, amino, and hydroxyl groups, which is beneficial to improving the dispersibility of the modified silicon carbide micropowders in the coating solution, and further enhancing the antibacterial property and filtration effect of the silicon carbide ceramic membrane.

[0020] In some embodiments, the sintering aid is any one or more of boron nitride, alumina, and yttrium oxide.

[0021] Preferably, the sintering aid is boron nitride.

[0022] In some embodiments, the first binder is any one or more of polyethylene glycol, hydroxypropyl methylcellulose, carboxymethyl chitosan, and sodium polyacrylate.

[0023] Preferably, the first binder is hydroxypropyl methylcellulose.

[0024] On the other hand, the present invention provides a method for preparing a silicon carbide ceramic membrane with excellent anti-pollution performance, comprising the following steps:

[0025] S1. Stir silicon carbide, sintering aid, zirconia whiskers, the first binder, and deionized water for 1 - 2 h, ball mill for 5 - 6 h, extrude into shape, heat to 300 - 350 °C at a heating rate of 1 - 3 °C / min, then heat to 600 - 620 °C at a heating rate of 2 - 4 °C / min, hold for 1 - 2 h, heat to 1300 - 1500 °C at a heating rate of 3 - 6 °C / min, hold for 2 - 4 h, and cool to obtain a silicon carbide support;

[0026] S2. Add modified silicon carbide micropowder to deionized water and stir at room temperature for 20 - 30 min, add the second binder, and stir at 30 - 50 °C for 1 - 3 h to obtain a coating solution;

[0027] S3. Coat the coating solution obtained in step S2 on the surface of the silicon carbide support obtained in step S1, keep warm at 120 - 130 °C for 1 - 2 h, then heat to 1300 - 1500 °C at a heating rate of 3 - 6 °C / min, and hold for 2 - 5 h to obtain the silicon carbide ceramic membrane with excellent anti-pollution performance.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) In the present invention, silicon carbide, sintering aid, carbon fiber are mixed with binder and deionized water, then ball milled, extruded into shape and sintered to obtain a silicon carbide support. Then, the coating solution prepared from modified silicon carbide micropowder, binder and deionized water is coated on the porous zirconia ceramic support and then calcined, so that the obtained silicon carbide ceramic membrane with excellent anti-pollution performance has excellent antibacterial property and filtration effect.

[0030] (2) By introducing copper ions onto the silicon carbide micropowder, the antibacterial property and filtration effect of the silicon carbide ceramic membrane can be improved. And copper trihydrate nitrate, citric acid and ammonia water can react to form tetraamminecopper ions and other ions. When they are loaded on the silicon carbide micropowder, they can produce strong hydrogen bond interactions with hydroxyl groups, carboxyl groups, etc. on water or binder, which is beneficial to promoting the dispersion of silicon carbide micropowder in the coating solution, making the pore size distribution of the ceramic membrane narrower, and then beneficial to improving the filtration effect of the ceramic membrane. In addition, tetraamminecopper ions are sintered to form cupric oxide during the preparation process of the coating layer, which can form a liquid phase at a lower temperature, fill the pores between silicon carbide particles, promote the rearrangement and sintering of particles, and is beneficial to improving the denseness of the ceramic membrane and making the pore size of the ceramic membrane smaller, and then beneficial to improving the anti-pollution performance of the ceramic membrane.

[0031] (3) In the present invention, a binder is synthesized by modifying sodium polyacrylate with 2-acrylamido-2-methylpropanesulfonic acid and 2-hydroxyethyl methacrylate, and used to prepare a ceramic membrane, which can further improve the anti-fouling performance of the ceramic membrane. This may be because the sulfonic acid groups on this binder can complex with copper ions, while the hydroxyl and amino groups can form strong hydrogen bond interactions with the modified ceramic micropowders, making the modified ceramic micropowders more easily dispersed in the coating solution, increasing the filtration accuracy of the ceramic membrane, and thus improving the anti-pollution performance and antibacterial performance of the ceramic membrane. Detailed implementation manners

[0032] The present invention will be described below in conjunction with specific implementation manners. It should be noted that the following examples are examples of the present invention, only used to illustrate the present invention, and not to limit the present invention. Other combinations and various improvements within the concept of the present invention can be made without departing from the main idea or scope of the present invention.

[0033] In the following examples and comparative examples, except for the modified silicon carbide micropowders and the second binder, the other compounds and related reagents used can be purchased from the market. Among them, the diameter of the zirconia whiskers is 0.1 - 1 μm, and the length is 20 - 30 μm, purchased from Ningbo Luofei Nano Technology Co., Ltd.; the average particle size of silicon carbide is 200 mesh, and the average particle size of silicon carbide micropowders is 5000 mesh, both purchased from Gongyi Yuying Refractory Materials Co., Ltd.; the average particle size of boron nitride micropowders is 1000 mesh, purchased from Beijing Huawei Ruike Chemical Technology Co., Ltd.

[0034] Preparation Example 1

[0035] A preparation method of modified silicon carbide micropowder - 1 includes the following steps: Add 2.5 g of copper nitrate trihydrate to 50 g of deionized water and stir at room temperature for 20 min, add 4.5 g of citric acid and 10 g of silicon carbide micropowders, stir at 800 rpm for 24 h, add 24 wt% ammonia water to adjust the pH to 7.5, and dry at 100 °C to obtain modified silicon carbide micropowder - 1.

[0036] Preparation Example 2

[0037] A preparation method of modified silicon carbide micropowder - 2, the specific implementation manner is the same as that of Preparation Example 1, the difference is that the addition amount of copper nitrate trihydrate is 5 g.

[0038] Preparation Example 3

[0039] A preparation method of modified silicon carbide micropowder - 3, the specific implementation manner is the same as that of Preparation Example 1, the difference is that the addition amount of citric acid is 8 g.

[0040] Preparation Example 4

[0041] Preparation method of Initiator-1, comprising the following steps: Add 1 g of ammonium persulfate and 2.5 g of mercaptoacetic acid to 10 g of deionized water, stir at room temperature for 25 min to obtain Initiator-1.

[0042] Preparation Example 5

[0043] Preparation method of Initiator-2, the specific implementation is the same as that of Preparation Example 4, the difference is that the addition amount of mercaptoacetic acid-1 is 0.5 g.

[0044] Preparation Example 6

[0045] Preparation method of Initiator-3, comprising the following steps: Add 3.5 g of ammonium persulfate to 10 g of deionized water, stir at room temperature for 25 min to obtain Initiator-3.

[0046] Preparation Example 7

[0047] Preparation method of the second binder-1, comprising the following steps: Add 10 g of acrylic acid, 2.5 g of 2-acrylamido-2-methylpropanesulfonic acid, and 2.5 g of 2-hydroxyethyl methacrylate to 50 g of deionized water, stir at 50 °C for 25 min, dropwise add 2 g of Initiator-1, after 30 min of dropping, raise the temperature to 70 °C and react for 4 h, add 50 wt% sodium hydroxide aqueous solution to adjust the pH to 7.5, and obtain the second binder-1 after drying.

[0048] Preparation Example 8

[0049] Preparation method of the second binder-2, the specific implementation is the same as that of Preparation Example 7, the difference is that the addition amount of 2-acrylamido-2-methylpropanesulfonic acid is 5 g.

[0050] Preparation Example 9

[0051] Preparation method of the second binder-3, the specific implementation is the same as that of Preparation Example 7, the difference is that the addition amount of 2-hydroxyethyl methacrylate is 5 g.

[0052] Preparation Example 10

[0053] Preparation method of the second binder-4, the specific implementation is the same as that of Preparation Example 7, the difference is that Initiator-1 is replaced with Initiator-2 in equal amount.

[0054] Preparation Example 11

[0055] Preparation method of the second binder-5, the specific implementation is the same as that of Preparation Example 7, the difference is that Initiator-1 is replaced with Initiator-3 in equal amount.

[0056] Preparation Example 12

[0057] The preparation method of the second binder-6 comprises the following steps: Add 10 g of acrylic acid and 2.5 g of hydroxyethyl methacrylate to 50 g of deionized water, stir at 50 °C for 25 min, dropwise add 2 g of initiator-1, after dropping for 30 min, raise the temperature to 70 °C and react for 4 h, add 50 wt% sodium hydroxide aqueous solution to adjust the pH to 7.5, and obtain the second binder-6 after drying.

[0058] Example 1

[0059] A silicon carbide ceramic membrane with excellent anti-pollution performance, comprising a silicon carbide support and a coating layer; the preparation of the silicon carbide support, in parts by weight, comprises the following raw materials: 90 parts of silicon carbide, 5 parts of boron nitride, 8 parts of zirconia whiskers, 7 parts of hydroxypropyl methylcellulose, 45 parts of deionized water; the preparation of the coating layer, in parts by weight, comprises the following raw materials: 60 parts of modified silicon carbide micropowder-1, 6 parts of the second binder-1, 50 parts of deionized water.

[0060] The preparation method of the silicon carbide ceramic membrane with excellent anti-pollution performance in this example comprises the following steps:

[0061] S1. Stir silicon carbide, boron nitride, zirconia whiskers, hydroxypropyl methylcellulose, and deionized water for 1.5 h, ball mill for 5.5 h, extrude into shape, raise the temperature to 325 °C at a heating rate of 2 °C / min, then raise the temperature to 610 °C at a heating rate of 3 °C / min, hold for 1.5 h, raise the temperature to 1400 °C at a heating rate of 4 °C / min, hold for 3 h, and cool to obtain the silicon carbide support;

[0062] S2. Add modified silicon carbide micropowder-1 to deionized water and stir at room temperature for 25 min, add the second binder-1, and stir at 40 °C for 2 h to obtain a coating solution;

[0063] S3. Coat the coating solution obtained in step S2 on the surface of the silicon carbide support obtained in step S1, control the coating thickness to be 120 μm, keep warm at 125 °C for 1.5 h, then raise the temperature to 1400 °C at a heating rate of 4 °C / min, and hold for 3.5 h to obtain the silicon carbide ceramic membrane with excellent anti-pollution performance.

[0064] Example 2

[0065] A silicon carbide ceramic membrane with excellent anti-pollution performance, comprising a silicon carbide support and a coating layer; the preparation of the silicon carbide support, in parts by weight, comprises the following raw materials: 80 parts of silicon carbide, 3 parts of boron nitride, 5 parts of zirconia whiskers, 5 parts of hydroxypropyl methylcellulose, 40 parts of deionized water; the preparation of the coating layer, in parts by weight, comprises the following raw materials: 50 parts of modified silicon carbide micropowder-1, 4 parts of the second binder-1, 40 parts of deionized water.

[0066] The preparation method of the silicon carbide ceramic membrane with excellent anti-pollution performance in this example comprises the following steps:

[0067] S1. Stir silicon carbide, boron nitride, zirconia whiskers, hydroxypropyl methylcellulose, and deionized water for 1 h, ball mill for 5 h, extrude into shape, heat to 300 °C at a heating rate of 1 °C / min, then heat to 600 °C at a heating rate of 2 °C / min, hold for 2 h, heat to 1300 °C at a heating rate of 3 °C / min, hold for 4 h, and cool to obtain a silicon carbide support;

[0068] S2. Add modified silicon carbide powder - 1 to deionized water and stir at room temperature for 20 min, then add the second binder - 1 and stir at 30 °C for 3 h to obtain a coating solution;

[0069] S3. Coat the coating solution obtained in step S2 on the surface of the silicon carbide support obtained in step S1, control the coating thickness to be 120 μm, keep at 120 °C for 2 h, then heat to 1300 °C at a heating rate of 3 °C / min, hold for 5 h to obtain a silicon carbide ceramic membrane with excellent anti - fouling performance.

[0070] Example 3

[0071] A silicon carbide ceramic membrane with excellent anti - fouling performance, comprising a silicon carbide support and a coating layer; to prepare the silicon carbide support, by weight, it contains the following raw materials: 100 parts of silicon carbide, 7 parts of boron nitride, 10 parts of zirconia whiskers, 10 parts of hydroxypropyl methylcellulose, and 50 parts of deionized water; to prepare the coating layer, by weight, it contains the following raw materials: 70 parts of modified silicon carbide powder - 1, 8 parts of the second binder - 1, and 60 parts of deionized water.

[0072] The preparation method of the silicon carbide ceramic membrane with excellent anti - fouling performance in this example comprises the following steps:

[0073] S1. Stir silicon carbide, boron nitride, zirconia whiskers, hydroxypropyl methylcellulose, and deionized water for 2 h, ball mill for 6 h, extrude into shape, heat to 350 °C at a heating rate of 3 °C / min, then heat to 620 °C at a heating rate of 4 °C / min, hold for 1 h, heat to 1500 °C at a heating rate of 6 °C / min, hold for 2 h, and cool to obtain a silicon carbide support;

[0074] S2. Add modified silicon carbide powder - 1 to deionized water and stir at room temperature for 30 min, then add the second binder - 1 and stir at 50 °C for 1 h to obtain a coating solution;

[0075] S3. Coat the coating solution obtained in step S2 on the surface of the silicon carbide support obtained in step S1, control the coating thickness to be 120 μm, keep at 130 °C for 1 h, then heat to 1500 °C at a heating rate of 6 °C / min, hold for 2 h to obtain a silicon carbide ceramic membrane with excellent anti - fouling performance.

[0076] Example 4

[0077] A silicon carbide ceramic membrane with excellent anti-pollution performance and its preparation method. The specific implementation manner is the same as that of Example 1, except that the modified silicon carbide micropowder-1 is replaced with the modified silicon carbide micropowder-2 in equal amount.

[0078] Example 5

[0079] A silicon carbide ceramic membrane with excellent anti-pollution performance and its preparation method. The specific implementation manner is the same as that of Example 1, except that the modified silicon carbide micropowder-1 is replaced with the modified silicon carbide micropowder-3 in equal amount.

[0080] Example 6

[0081] A silicon carbide ceramic membrane with excellent anti-pollution performance and its preparation method. The specific implementation manner is the same as that of Example 1, except that the second binder-1 is replaced with the second binder-2 in equal amount.

[0082] Example 7

[0083] A silicon carbide ceramic membrane with excellent anti-pollution performance and its preparation method. The specific implementation manner is the same as that of Example 1, except that the second binder-1 is replaced with the second binder-3 in equal amount.

[0084] Example 8

[0085] A silicon carbide ceramic membrane with excellent anti-pollution performance and its preparation method. The specific implementation manner is the same as that of Example 1, except that the second binder-1 is replaced with the second binder-4 in equal amount.

[0086] Example 9

[0087] A silicon carbide ceramic membrane with excellent anti-pollution performance and its preparation method. The specific implementation manner is the same as that of Example 1, except that the second binder-1 is replaced with the second binder-5 in equal amount.

[0088] Example 10

[0089] A silicon carbide ceramic membrane with excellent anti-pollution performance and its preparation method. The specific implementation manner is the same as that of Example 1, except that the second binder-1 is replaced with the second binder-6 in equal amount.

[0090] Comparative Example 1

[0091] A silicon carbide ceramic membrane with excellent anti-pollution performance and its preparation method. The specific implementation manner is the same as that of Example 1, except that the modified silicon carbide micropowder-1 is replaced with silicon carbide micropowder in equal amount.

[0092] Performance test

[0093] The silicon carbide ceramic membranes with excellent anti-pollution performance obtained in the above examples and comparative examples were tested:

[0094] (1) Antibacterial performance: Cut the silicon carbide ceramic membranes with good anti-pollution performance into small pieces of 1.0 cm × 4.0 cm, and place them in 200 mL of Escherichia coli suspension with a viable bacteria concentration of 6.2×10 6 CFU·mL -1 . Incubate them in a constant temperature incubator at 37°C with shaking at 121 rpm for 6 h. Use the dilution plate counting method to measure the viable bacteria concentration w in the treated suspension. Calculate the antibacterial rate of Escherichia coli according to the formula 100%×(6.2×10 6 -w) / (6.2×10 6 ).

[0095] (2) Anti-pollution performance: Install the silicon carbide ceramic membranes with good anti-pollution performance into the reverse osmosis wastewater treatment equipment. Use heavy metal wastewater as the test water. Control the average daily treatment volume of the reverse osmosis wastewater treatment equipment to be 60 m 3 , the reverse osmosis pressure to be 0.6 MPa, and the reverse osmosis temperature to be 45°C. Conduct reverse osmosis wastewater treatment on the test water and detect various indicators of the reclaimed water obtained after reverse osmosis treatment.

[0096] Among them, in the test water, the concentration of Pb 2+ is 251.3 mg / L, the concentration of Ni 2+ is 34.5 mg / L, the concentration of Zn 2+ is 4.7 mg / L, and the COD cr value is 203 mg / L.

[0097] (3) Filtration accuracy: Use the mercury intrusion porosimeter method to measure the pore size of the ceramic membrane to evaluate the filtration accuracy.

[0098] The test results are shown in Table 1:

[0099] Table 1

[0100]

[0101]

[0102] As can be seen from the data in Table 1, the silicon carbide ceramic membranes prepared in Examples 1-3 have excellent antibacterial, anti-pollution properties and filtration accuracy. By comparing Example 1 with Examples 4 and 5, it can be seen that changing the ratio of copper nitrate trihydrate to silicon carbide micropowder or the ratio of citric acid to silicon carbide micropowder will cause the generated copper oxide to block the pores between silicon carbide particles, reducing the number of pores, and further reducing the pores on the silicon carbide ceramic membrane, resulting in poor antibacterial and anti-pollution properties of the silicon carbide ceramic membrane and a smaller pore size; by comparing Example 1 with Examples 6 and 7, it can be seen that changing the ratio of acrylic acid to 2-acrylamido-2-methylpropanesulfonic acid or the ratio of acrylic acid to 2-hydroxyethyl methacrylate will make the dispersibility of the second binder poor, and the complexation effect with copper ions poor, resulting in poor antibacterial, anti-pollution properties and filtration accuracy of the silicon carbide ceramic membrane; by comparing Example 1 with Examples 8 and 9, it can be seen that changing the ratio of ammonium persulfate to mercaptoacetic acid or not adding mercaptoacetic acid will make the tetraamminecopper ions on the surface of the modified silicon carbide micropowder easily oxidized and decomposed during drying, slightly reducing the anti-pollution properties, anti-pollution properties and filtration accuracy of the silicon carbide ceramic membrane; by comparing Example 1 with Example 10, it can be seen that not introducing the 2-acrylamido-2-methylpropanesulfonic acid chain segment into the second binder will make the antibacterial, anti-pollution properties and filtration accuracy of the silicon carbide ceramic membrane poor; by comparing Example 1 with Comparative Example 1, it can be seen that adding unmodified silicon carbide micropowder results in poor anti-pollution properties, anti-pollution properties and filtration accuracy of the silicon carbide ceramic membrane.

[0103] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it. It should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A silicon carbide ceramic membrane with excellent anti-pollution performance, characterized in that, It includes a silicon carbide support and a coating film layer; to prepare the silicon carbide support, based on parts by weight, it includes the following raw materials: 80-100 parts of silicon carbide, 3-7 parts of sintering aid, 5-10 parts of zirconia whiskers, 5-10 parts of the first binder, and 40-50 parts of deionized water; to prepare the coating film layer, based on parts by weight, it includes the following raw materials: 50-70 parts of modified silicon carbide micropowder, 4-8 parts of the second binder, and 40-60 parts of deionized water.

2. The anti-pollution excellent silicon carbide ceramic membrane according to claim 1, wherein The preparation method of the modified silicon carbide micropowder includes the following steps: Add copper nitrate trihydrate to deionized water and stir at room temperature for 15-25 min, add citric acid and silicon carbide micropowder, stir at 700-900 rpm for 20-28 h, add 20-28 wt% ammonia water to adjust the pH to 7-8, and dry at 80-120 °C to obtain the modified silicon carbide micropowder.

3. The silicon carbide ceramic membrane with excellent anti-pollution property according to claim 2, characterized in that, The particle size of the silicon carbide micropowder is 3000-6000 mesh.

4. The anti-pollution excellent silicon carbide ceramic membrane according to claim 2, characterized in that, The mass ratio of the copper nitrate trihydrate, citric acid, and silicon carbide micropowder is (0.1-0.4):(0.25-0.65):

1.

5. The silicon carbide ceramic membrane with excellent anti-pollution performance according to claim 1, wherein The preparation method of the second binder includes the following steps: Add acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and 2-hydroxyethyl methacrylate to deionized water, stir at 45-55 °C for 20-30 min, add an initiator, raise the temperature to 65-75 °C and react for 3-5 h, add 45-55 wt% sodium hydroxide aqueous solution to adjust the pH to 7-8, and obtain the second binder after drying.

6. The anti-pollution excellent silicon carbide ceramic membrane according to claim 5, characterized in that, The preparation method of the initiator includes the following steps: Add ammonium persulfate and mercaptoacetic acid to deionized water, and the mass ratio of the three is (0.05-0.15):(0.1-0.4):1, stir at room temperature for 20-30 min to obtain the initiator.

7. The silicon carbide ceramic membrane with excellent anti-pollution performance according to claim 5, characterized in that, The mass ratio of the acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and 2-hydroxyethyl methacrylate is 1:(0.1-0.4):(0.1-0.4).

8. The silicon carbide ceramic membrane with excellent anti-pollution property according to claim 1, characterized in that, The sintering aid is any one or more of boron nitride, alumina, and yttrium oxide.

9. The anti-pollution excellent silicon carbide ceramic membrane according to claim 1, characterized in that, The first binder is any one or more of polyethylene glycol, hydroxypropyl methylcellulose, carboxymethyl chitosan, and sodium polyacrylate.

10. A method for preparing a silicon carbide ceramic membrane with excellent anti-pollution performance according to any one of claims 1-9, characterized in that, It includes the following steps: S1. Stir silicon carbide, sintering aid, zirconia whiskers, the first binder, and deionized water for 1-2 h, ball mill for 5-6 h, extrude into shape, raise the temperature to 300-350 °C at a heating rate of 1-3 °C / min, then raise the temperature to 600-620 °C at a heating rate of 2-4 °C / min, hold for 1-2 h, raise the temperature to 1300-1500 °C at a heating rate of 3-6 °C / min, hold for 2-4 h, and cool to obtain the silicon carbide support; S2. Add the modified silicon carbide micropowder to deionized water and stir at room temperature for 20-30 min, add the second binder, and stir at 30-50 °C for 1-3 h to obtain the coating liquid; S3. Coat the surface of the silicon carbide support obtained in step S1 with the coating solution obtained in step S2, keep it at 120 - 130 °C for 1 - 2 h, then raise the temperature to 1300 - 1500 °C at a heating rate of 3 - 6 °C / min, and maintain it for 2 - 5 h to obtain the silicon carbide ceramic membrane with excellent anti-pollution performance.

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