Silicon carbide film and preparation method thereof

Abstract

The invention provides a silicon carbide film which comprises a ceramic support body, and the ceramic support body is prepared by extruding and sintering inorganic silicon carbide powder serving as aggregate; the separation layer is prepared by taking the film layer powder as aggregate and carrying out dipping, pulling and heat treatment with auxiliary materials, and relates to the technical field of silicon carbide film preparation. The cross-layer preparation of the high-interception and high-flux silicon carbide ceramic membrane is realized by adopting extrusion molding and dip-coating processes. The ceramic membrane prepared through the extrusion molding process is uniform and flat in membrane layer structure and has the advantages that the membrane thickness is adjustable, and the membrane layer integrity is not affected by the surface roughness of the supporting body; by adding the negative pressure suction process, the attaching degree between the film layer and the supporting body is improved, and the binding force of the sintered film substrate is greatly improved. The ceramic membrane prepared by the invention has the advantages of concentrated pore size distribution, high flux and thermal shock resistance, and provides a reference for preparing the high-flux ceramic membrane.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon carbide film preparation, in particular to a silicon carbide film and a preparation method thereof. Background Art

[0002] Caprolactam is an important chemical raw material, primarily used in the production of polyamide 6 chips, which are then further processed into fibers, engineering plastics, films, and other products, offering broad application prospects. The liquid-phase Beckmann rearrangement process utilizes highly corrosive oleum, which is highly corrosive to equipment and produces a large amount of low-value ammonium sulfate as a by-product. The vapor-phase Beckmann rearrangement process, however, has garnered widespread attention in recent years because it utilizes a solid acid catalyst, avoids oleum, eliminates the neutralization step, and produces no ammonium sulfate by-product.

[0003] In recent years, oxides and molecular sieves have been widely studied as catalysts. Molecular sieves, with their unique pores and large surface area, have garnered significant attention in the fields of adsorption, separation, and catalysis. High-silicon molecular sieves, in particular, are particularly effective and hold great promise for industrial application. However, the extremely small particle size of molecular sieves makes effective gas-solid separation difficult, and catalyst recovery and reuse difficult. Furthermore, they suffer from poor catalyst stability, high reaction temperatures, and poor selectivity for caprolactam. To address these issues, scientists have developed various types of molecular sieve catalysts, achieving efficient catalytic vapor-phase rearrangement of cyclohexanone oxime to caprolactam on a fixed bed. A vapor-phase rearrangement process combining high-silicon molecular sieves with a fluidized bed has also been developed and commercialized. However, in this fluidized bed process, the catalyst particles are subjected to intense collision and friction, placing high demands on the catalyst's mechanical properties and wear resistance. Furthermore, the separation requirements of the catalyst and reaction products complicate practical operations, limiting market competitiveness. Sinopec Research Institute of Petroleum Processing has developed a silicon titanium molecular sieve using hydrothermal synthesis-rearrangement modification technology. This unique hollow structure improves the catalyst's physical properties and stability. This technology also overcomes the technical challenge of membrane clogging during membrane separation in alkaline environments, innovatively developing a single-reactor continuous slurry bed reaction process combining reaction and membrane separation. Furthermore, existing technologies have developed a radial moving bed reaction technology for the vapor-phase Beckmann rearrangement of cyclohexanone oxime, enabling online catalyst removal. However, controlling the uniform downward movement of the catalyst in the moving bed reactor is difficult.

[0004] However, the reaction temperature of cyclohexanone oxime gas-phase rearrangement is high, and the catalyst is prone to coking and deactivation. To achieve continuous operation of the catalyst reaction and regeneration, and to achieve synergistic coupling of catalytic reaction and membrane separation enhancement, the molecular sieve catalyst is retained in situ to achieve gas-solid separation of the reaction products and the catalyst. This invention, by separately preparing the support and membrane layer, produces a high-retention, high-throughput silicon carbide ceramic membrane without a transition layer. This membrane is applied in the field of gas-solid separation, providing new ideas for constructing coupled catalytic reaction and membrane separation systems and developing equipment that can meet the requirements of high-concentration industrial reactions and separations. Summary of the Invention

[0005] The object of the present invention is to provide a silicon carbide film and a method for preparing the same, so as to solve the problems raised in the background technology described above and overcome the technical defects thereof.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a silicon carbide membrane, comprising a ceramic support body, wherein the ceramic support body is made of inorganic silicon carbide powder as an aggregate and is extruded and sintered; a separation layer, wherein the separation layer is made of membrane layer powder as an aggregate and is impregnated, pulled and heat-treated with auxiliary materials; and a ceramic membrane, wherein the separation layer is flattened on the ceramic support body and then vacuum-sucked and dried and sintered. The average pore size of the silicon carbide ceramic membrane is 15.4-16.8 μm, and the gas permeability of the silicon carbide ceramic membrane is 596.1-624.6 m 3 m 2 h 1 kPa 1 The thickness of the silicon carbide ceramic membrane is 2.0-2.5 mm.

[0007] A silicon carbide film and a method for preparing the same, comprising: Step S1: After the inorganic silicon carbide powder, sintering aid, and binder are mixed, a single-channel tubular ceramic-based support is formed under extrusion molding conditions at a pressure of 5-30 MPa and a residence time of 5-60 seconds. The single-channel tubular ceramic-based support is then formed into a silicon carbide ceramic support under a high-temperature sintering environment at a sintering temperature of 1000-1600°C, a heating and cooling rate of 0.5-3°C / min, and a holding time of 1-5 hours. Step S2: The membrane layer powder aggregate and auxiliary materials are successively prepared, and then subjected to ball milling for 0.5-6 hours, mixing and stirring for 0.5-6 hours, and suction degassing for 10-120 minutes to obtain a homogeneous coating liquid, which is then immersed and pulled at a speed of 1-50 mm / s and input into a heat treatment furnace at 20-120°C for a treatment time of 0.5-24 hours; Step S3: After wetting the support with deionized water, the separation layer is evenly spread on the ceramic support. After the air is removed by negative pressure suction for 1-120 minutes, the ceramic membrane is formed in a drying environment of 20-120°C for 0.5-24 hours, and a sintering environment of 1000°C-1450°C, a heating and cooling rate of 0.5-3°C / min, and a holding time of 1-5 hours.

[0008] As a further solution of the present invention: a silicon carbide membrane, the ceramic support body is mixed with inorganic silicon carbide powder aggregate and then extruded to form a single-channel tubular ceramic-based support body, and the single-channel tubular ceramic-based support body is sintered at high temperature to form a silicon carbide ceramic support body.

[0009] As a further solution of the present invention: a silicon carbide film, the film layer powder is silicon carbide powder, the auxiliary material includes a homogeneous coating liquid, the homogeneous coating liquid is made by mixing a binder, a dispersant and a defoaming agent, and the ratio of the silicon carbide powder: binder: dispersant is 20:20-60:2-60.

[0010] As a further solution of the present invention: a silicon carbide membrane, wherein the contact surface between the ceramic support body and the separation layer is wetted by ionized water.

[0011] As a further solution of the present invention: a silicon carbide membrane also includes a sintering aid and a binder, which are added when the ceramic support body is made into a single-channel tubular ceramic-based support body, and the sintering aid includes one or more of ZrO2, CaO, graphite, CeO2, NaA, Y2O3, Al2O3 or water glass, and the binder includes one or more of PVA, PVB, glycerol, silica sol, PESf or HPMC.

[0012] As a further solution of the present invention: a silicon carbide film, wherein the ratio of the inorganic silicon carbide powder: the sintering aid: the binder is 10-200:1-50:1, and the mass fraction of the binder is 10wt%.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention achieves cross-layer preparation of high-retention, high-flux silicon carbide ceramic membranes by adopting extrusion molding and impregnation pulling processes. The ceramic membranes prepared by the extrusion molding process have a uniform and smooth membrane layer structure, adjustable membrane thickness, and the membrane layer integrity is not affected by the surface roughness of the support body. By adding a negative pressure suction process, the degree of adhesion between the membrane layer and the support body is improved, and the bonding strength of the membrane base after sintering is greatly improved. The ceramic membranes prepared by the present invention have the advantages of concentrated pore size distribution, high flux, and thermal shock resistance, providing a reference for the preparation of high-flux ceramic membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The disclosure of the present invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components. Among them: Figure 1 The figure schematically shows a flow chart according to one embodiment of the present invention.

[0015] Figure 2 The electron microscope image of the surface of the silicon carbide support body proposed in Example 3 of the present invention is schematically shown.

[0016] Figure 3 The electron microscope image of the silicon carbide film layer proposed in Example 3 of the present invention is schematically shown.

[0017] Figure 4 The electron microscope image of the cross section of the silicon carbide ceramic membrane proposed in Example 3 of the present invention is schematically shown. DETAILED DESCRIPTION

[0018] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the present invention.

[0019] According to one embodiment of the present invention, a silicon carbide membrane is shown in conjunction with the accompanying drawings, including a ceramic support body, the ceramic support body is made of inorganic silicon carbide powder as an aggregate and extruded and sintered, the ceramic support body is mixed with the inorganic silicon carbide powder aggregate and then extruded to form a single-channel tubular ceramic-based support body, the single-channel tubular ceramic-based support body is sintered at a high temperature to form a silicon carbide ceramic support body, and at the same time, it also includes a sintering aid and a binder, the sintering aid and the binder are added when the ceramic support body is made into a single-channel tubular ceramic-based support body, the sintering aid includes ZrO2, CaO, graphite, CeO2, NaA, Y2O3, A l2O3 or water glass, etc., and the binder includes one or more of PVA, PVB, glycerol, silica sol, PESf or HPMC. Specifically, after the inorganic silicon carbide powder, sintering aid and binder are mixed, a single-channel tubular ceramic base support is formed under extrusion molding conditions at a pressure of 5-30 MPa and a residence time of 5-60 seconds. Then, the single-channel tubular ceramic base support is formed into a silicon carbide ceramic support under a high-temperature sintering environment with a sintering temperature of 1000-1600°C, a heating and cooling rate of 0.5-3°C / min, and a holding time of 1-5 hours. Other embodiments of the present invention further include a separation layer, which is made of a film layer powder as an aggregate and after impregnation, pulling and heat treatment of auxiliary materials. The film layer powder is silicon carbide powder, and the auxiliary materials include a homogeneous coating liquid, which is made by mixing a binder, a dispersant and a defoaming agent. The ratio of silicon carbide powder: binder: dispersant is 20:20-60:2-60, and the ratio of inorganic silicon carbide powder: sintering aid: binder is 10-200:1-50:1. The mass fraction of the binder is 10wt%. Specifically, the film layer powder aggregate and the auxiliary materials are successively prepared, and after preparation, they are successively subjected to 0.5-6h ball milling, 0.5-6h mixing and stirring, and 10-120min suction degassing to obtain a homogeneous coating liquid, which is then input into a heat treatment furnace at 20-120°C and a treatment time of 0.5-24h after impregnation and pulling at 1-50mm / s; Other embodiments of the present invention also include a ceramic membrane, in which the separation layer is laid flat on a ceramic support body, vacuum suction is applied, and the membrane is dried and sintered. The contact surface between the ceramic support body and the separation layer is moistened with ionized water. Specifically, the support body is moistened with deionized water and the separation layer is evenly laid flat on the ceramic support body. After the air is removed by vacuum suction for 1-120 minutes, the ceramic membrane is formed in a drying environment of 20-120°C and 0.5-24 hours, a sintering environment of 1000°C-1450°C, a heating and cooling rate of 0.5-3°C / min, and a holding time of 1-5 hours. The average pore size of the silicon carbide ceramic membrane is 15.4-16.8 μm, and the gas permeability of the silicon carbide ceramic membrane is 596.1-624.6 m 3 m 2 h 1 kPa 1 , the thickness of silicon carbide ceramic membrane is 2.0-2.5mm.

[0020] Specifically, the present application lists the following examples to demonstrate the actual preparation of membranes under different physical and chemical conditions: Example 1 50μm silicon carbide, glycerol, and 10 wt% polyvinyl alcohol (PVA) were mixed in a mass ratio of 50:2:1 for silicon carbide powder:glycerol:PVA. A single-channel tubular silicon carbide support was prepared by extrusion molding at a pressure of 10 MPa and a residence time of 40 s. The silicon carbide support was then dried and sintered at 1450°C with a heating and cooling rate of 2.0°C / min and a holding time of 2 h. A coating solution was prepared by mixing 3μm silicon carbide powder, 15 wt% polyvinyl alcohol (PVA), 4 wt% methylcellulose (MC), and water in a mass ratio of 20:30:50:1. Several drops of defoamer were also added. The mixing conditions were ball milling for 6 h, followed by high-speed stirring for 0.5 h, and finally vacuum degassing for 10 min. The slurry was then impregnated, pulled, dried, and cut to obtain a membrane. During the prefabricated membrane immersion and pulling process, the pulling speed was 5 mm / s, and then the prefabricated membrane layer was dried at 25°C for 24 hours; the support was moistened with deionized water, and the membrane layer was evenly spread on the ceramic support. After negative pressure suction for 10 minutes, it was tightly fitted to the support. After drying at 120°C for 1 hour, it was sintered to obtain a silicon carbide ceramic membrane. The sintering temperature was 1250°C, the heating and cooling rate was 0.5°C / min, and the holding time was 2 hours.

[0021] Example 2 1000 μm silicon carbide powder, 10 wt% silica sol, and 6 wt% CMC were mixed in a mass ratio of silicon carbide: silica sol: CMC = 100:5:1. A single-channel tubular silicon carbide support green body was prepared by extrusion molding with a pressure controlled at 15 MPa and a residence time of 20 s. The silicon carbide support was obtained by drying and sintering at a sintering temperature of 1600°C, a heating and cooling rate of 3°C / min, and a holding time of 3 h. A coating solution was prepared by mixing 50 μm silicon carbide powder, 10 wt% polyvinyl alcohol (PVA), 6 wt% methylcellulose (MC), and water in a mass ratio of 20:50:30:2. Several drops of defoamer were also added. The mixing conditions included ball milling for 0.5 h, high-speed stirring for 6 h, and degassing by suction for 120 min. The coating solution was then subjected to dip-pulling, drying, and cutting to obtain a membrane. During the dip-pulling process, the prefabricated membrane was pulled at a speed of 50 mm / s. The prefabricated membrane was then dried at 40°C for 18 h. The support was moistened with deionized water and evenly applied to the ceramic support. After vacuum suction for 120 min, the membrane was dried at 80°C for 12 h and sintered to obtain a silicon carbide ceramic membrane. The sintering temperature was 1450°C, the heating and cooling rate was 3°C / min, and the holding time was 5 h.

[0022] Example 3 100 μm silicon carbide powder, coal gangue, graphite and 10 wt% HPMC were mixed, where the mass ratio of silicon carbide powder: coal gangue: graphite was 70: (4-16): (4-16). A single-channel tubular silicon carbide support green body was prepared by extrusion molding, with the pressure controlled at 8 MPa and the pressing time being 10 s. The silicon carbide support was obtained by drying and sintering, with the sintering temperature at 1400 °C, the heating and cooling rates at 2 °C / min, and the holding time being 4 h. 5μm silicon carbide powder, 10 wt% PVA, 10wt% PVP and water were mixed in a certain mass ratio to prepare a coating liquid, wherein silicon carbide powder: PVA: PVP: water = 20:40:40:1 (mass ratio), and a few drops of defoaming agent were added at the same time; the mixing conditions were ball milling for 3 hours, high-speed stirring for 3 hours, and finally degassing by suction for 60 minutes; the slurry was subjected to impregnation, pulling and heat treatment and sintering to obtain a separation layer. During the impregnation and pulling process of the separation layer, the pulling speed was 50 mm / s, and the prefabricated membrane layer was then dried at 60°C for 12 hours; the support was moistened with deionized water, and the membrane layer was evenly spread on the ceramic support. After negative pressure suction for 30 minutes, it was tightly attached to the support, and then dried at 60°C for 12 hours and sintered to obtain a silicon carbide ceramic membrane. The sintering temperature was 1200°C, the heating and cooling rates were 2°C / min, the holding time was 2 hours, and according to Figure 2 、 Figure 3 and Figure 4 The electron microscope images provided show that the average pore size of the membrane prepared in this embodiment is 16 μm, the membrane thickness is 2.2 mm, and the air flux is 611 m 3 m 2 h 1 kPa 1 .

[0023] Example 4 300 μm silicon carbide powder, 5 wt% silica sol, and 6 wt% PVA were mixed in a mass ratio of 80:8:1. A single-channel tubular silicon carbide support green body was prepared by extrusion molding. The pressure was controlled at 20 MPa and the pressing time was 15 s. The silicon carbide support was obtained by drying and sintering. The sintering temperature was 1450 °C, the heating and cooling rate was 1.5 °C / min, and the holding time was 5 h. The coating solution was prepared by mixing 10 μm silicon carbide powder, 10 wt% PVA, 5 wt% PVP, and water in a certain mass ratio (silicon carbide powder: PVA: PVP: water = 20:35:55:1.5 (mass ratio), and adding a few drops of defoamer. The mixing conditions were ball milling for 5 h, high-speed stirring for 1 h, and finally degassing by suction for 40 min. The slurry was impregnated, pulled, dried, and cut to obtain the film layer. During the prefabricated membrane immersion and pulling process, the pulling movement speed was 40 mm / s, and then the prefabricated membrane layer was dried at 120°C for 0.5 h; the support was moistened with deionized water, and the membrane layer was evenly spread on the ceramic support. After negative pressure suction for 45 minutes, it was tightly adhered to the support. After drying at 80°C for 6 hours, it was sintered to obtain a silicon carbide ceramic membrane. The sintering temperature was 1350°C, the heating and cooling rate was 1.5°C / min, and the holding time was 4 hours.

[0024] Example 5 120 μm silicon carbide powder, 6 wt% silica sol, and 8 wt% PVA were mixed in a mass ratio of silicon carbide powder: silica sol: PVA = 60:5:1. A single-channel tubular silicon carbide support green body was prepared by extrusion molding with a pressure of 15 MPa and a pressing time of 30 s. The silicon carbide support was obtained by drying and sintering at a sintering temperature of 1450°C, a heating and cooling rate of 2°C / min, and a holding time of 4 h. The coating solution was prepared by mixing 5μm silicon carbide powder, 12 wt% PVA, 4 wt% CMC, and water in a certain mass ratio (silicon carbide powder: PVA: CMC: water = 20:40:45:1.5 (mass ratio), and adding a few drops of defoamer. The mixing conditions were ball milling for 3 h, high-speed stirring for 1.5 h, and finally degassing by suction for 60 min. The slurry was impregnated, pulled, dried, and cut to obtain the film layer. During the prefabricated membrane immersion and pulling process, the pulling speed was 45 mm / s, and then the prefabricated membrane layer was dried at 120°C for 1 hour; the support was moistened with deionized water, and the membrane layer was evenly spread on the ceramic support. After negative pressure suction for 60 minutes, it was tightly adhered to the support. After drying at 90°C for 4 hours, it was sintered to obtain a silicon carbide ceramic membrane. The sintering temperature was 1450°C, the heating and cooling rate was 1.5°C / min, and the holding time was 4 hours.

[0025] Example 6 100 μm silicon carbide powder, 8 wt% silica sol and 12 wt% PVA were mixed, wherein the silicon carbide powder: silica sol: PVA = 90:5:1 (mass ratio); a single-channel tubular silicon carbide support green body was prepared by extrusion molding, the pressure was controlled at 15 MPa, and the pressing time was 45 s; the silicon carbide support was obtained by drying and sintering, the sintering temperature was 1350 ° C, the heating and cooling rate was 0.5 ° C / min, and the holding time was 2 h. A coating solution was prepared by mixing 3μm silicon carbide powder, 10 wt% polyvinyl alcohol (PVA), 8 wt% polyvinyl alcohol (PVP), and water in a mass ratio of 20:35:55:1.5. Several drops of defoamer were also added. The mixing conditions included ball milling for 4 hours, high-speed stirring for 1 hour, and degassing by suction for 60 minutes. The slurry was then subjected to impregnation, pulling, drying, and cutting to obtain a membrane. During the impregnation and pulling process, the pulling speed was 30 mm / s. The preformed membrane was then dried at 90°C for 2 hours. The support was moistened with deionized water and evenly spread onto the ceramic support. After vacuum suction for 60 minutes, the membrane was dried at 70°C for 8 hours and sintered to obtain the silicon carbide ceramic membrane. The sintering temperature was 1300°C, the heating and cooling rates were 1.5°C / min, and the holding time was 4 hours.

[0026] Example 7 60μm silicon carbide powder, Y2O3, Al2O3 and PESf were mixed, where the mass ratio of silicon carbide powder: Y2O3: Al2O3: PESf was 50:1:1:1. A single-channel tubular silicon carbide support green body was prepared by extrusion molding, with the pressure controlled at 15 MPa and the pressing time being 45 s. The silicon carbide support was obtained by drying and sintering, with the sintering temperature at 1400℃, the heating and cooling rates at 2℃ / min, and the holding time being 4 h. A coating solution was prepared by mixing 2μm silicon carbide powder, 10 wt% polyvinyl alcohol (PVA), 8 wt% polyvinyl alcohol (PVP), and water in a mass ratio of 20:20:35:1. Several drops of defoamer were also added. The mixing conditions included ball milling for 3 hours, high-speed stirring for 2 hours, and degassing by suction for 40 minutes. The slurry was then subjected to impregnation, pulling, drying, and cutting to obtain a membrane. During the impregnation and pulling process, the pulling speed was 35 mm / s. The preformed membrane was then dried at 120°C for 1 hour. The support was moistened with deionized water and evenly spread onto the ceramic support. After vacuum suction for 30 minutes, the membrane was dried at 120°C for 2 hours and sintered to obtain a silicon carbide ceramic membrane. The sintering temperature was 1450°C, the heating and cooling rate was 2°C / min, and the holding time was 3 hours.

[0027] Working Principle: The present invention achieves cross-layer preparation of high-retention, high-flux silicon carbide ceramic membranes by adopting extrusion molding and impregnation pulling processes. The ceramic membrane prepared by the extrusion molding process has a uniform and flat membrane structure, and has the advantages of adjustable membrane thickness and membrane integrity that is not affected by the surface roughness of the support body. By adding a negative pressure suction process, the degree of fit between the membrane layer and the support body is improved, and the bonding strength of the membrane base after sintering is greatly improved. The ceramic membrane prepared by the present invention has the advantages of concentrated pore size distribution, high flux, and thermal shock resistance, providing a reference for the preparation of high-flux ceramic membranes.

[0028] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A silicon carbide film, characterized in that: The ceramic support comprises a ceramic support body, wherein the ceramic support body is made of inorganic silicon carbide powder as aggregate and is extruded and sintered; The separation layer is made of the membrane layer powder as the aggregate and the auxiliary materials through impregnation, pulling and heat treatment; as well as The ceramic membrane is made by laying the separation layer on the ceramic support, vacuuming, drying and sintering. The average pore size of the silicon carbide ceramic membrane is 15.4-16.8 μm, and the gas permeability of the silicon carbide ceramic membrane is 596.1-624.6 m 3 m 2 h 1 kPa 1 The thickness of the silicon carbide ceramic membrane is 2.0-2.5 mm.

2. The silicon carbide film according to claim 1, wherein The ceramic support is mixed with inorganic silicon carbide powder aggregate and then extruded to form a single-channel tubular ceramic-based support. The single-channel tubular ceramic-based support is then sintered at a high temperature to form a silicon carbide ceramic support.

3. The silicon carbide film according to claim 1, wherein The film layer powder is silicon carbide powder, the auxiliary material includes a homogeneous coating liquid, and the homogeneous coating liquid is made by mixing a binder, a dispersant and a defoamer. The ratio of the silicon carbide powder: the binder: the dispersant is 20:20-60:2-60.

4. The silicon carbide film according to claim 1, wherein The contact surface between the ceramic support and the separation layer is wetted by ionized water.

5. The silicon carbide film according to claim 4, characterized in that: It also includes a sintering aid and a binder, which are added when the ceramic support is made into a single-channel tubular ceramic-based support. The sintering aid includes one or more of ZrO2, CaO, graphite, CeO2, NaA, Y2O3, Al2O3 or water glass, and the binder includes one or more of PVA, PVB, glycerol, silica sol, PESf or HPMC.

6. The silicon carbide film according to claim 5, characterized in that: The ratio of the inorganic silicon carbide powder: the sintering aid: the binder is 10-200:1-50:1, and the mass fraction of the binder is 10 wt%.

7. A silicon carbide film and a method for preparing the same according to claim 6, characterized in that: include Step S1: After the inorganic silicon carbide powder, sintering aid, and binder are mixed, a single-channel tubular ceramic-based support is formed under extrusion molding conditions at a pressure of 5-30 MPa and a residence time of 5-60 seconds. The single-channel tubular ceramic-based support is then formed into a silicon carbide ceramic support under a high-temperature sintering environment at a sintering temperature of 1000-1600°C, a heating and cooling rate of 0.5-3°C / min, and a holding time of 1-5 hours. Step S2: The membrane layer powder aggregate and auxiliary materials are successively prepared, and then subjected to ball milling for 0.5-6 hours, mixing and stirring for 0.5-6 hours, and suction degassing for 10-120 minutes to obtain a homogeneous coating liquid, which is then immersed and pulled at a speed of 1-50 mm / s and input into a heat treatment furnace at 20-120°C for a treatment time of 0.5-24 hours; Step S3: After wetting the support with deionized water, the separation layer is evenly spread on the ceramic support. After the air is removed by negative pressure suction for 1-120 minutes, the ceramic membrane is formed in a drying environment of 20-120°C for 0.5-24 hours, and a sintering environment of 1000°C-1450°C, a heating and cooling rate of 0.5-3°C / min, and a holding time of 1-5 hours.

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