Whisker-reinforced dual-layer porous ceramic plate, and preparation method therefor and application thereof

Abstract

Disclosed in the present invention are a whisker-reinforced dual-layer porous ceramic plate, and a preparation method therefor and an application thereof. The whisker-reinforced dual-layer porous ceramic plate comprises an interception layer and a support layer; the interception layer is provided with through holes and has a thickness of 45-120 μm; the support layer has a cavity structure; the through holes of the interception layer are in communication with the cavity structure; whiskers having a mesh structure are distributed in the through holes of the interception layer and the cavity structure; the interconnected porosity of the whisker-reinforced dual-layer porous ceramic plate is 54-80%. The whisker-reinforced dual-layer porous ceramic plate in the present invention can effectively filter solid particulate matter and conduct oil-water separation, is not prone to clogging, and is suitable for treating oily wastewater containing solid particulate matter; moreover, the treatment performance can be restored by means of backwashing technology, and the present invention has the characteristics of high performance and low cost, and is suitable for industrial application.

Description

Whisker-reinforced double-layer porous ceramic plate, preparation method and application thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to the Chinese patent application with the application number 202410758389.X and the invention title "Whisker-reinforced double-layer porous ceramic plate, preparation method and application thereof", which was filed on June 13, 2024 with the Chinese Patent Office, the content of the above application is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of oil-water separation ceramic materials, in particular, to a whisker-reinforced double-layer porous ceramic plate, a preparation method and application thereof. BACKGROUND

[0004] Many industries such as petroleum chemical industry, textile industry, metal smelting, food processing, etc. will discharge a large amount of industrial oil-containing wastewater; and due to the habit of cooking by frying, roasting, boiling, etc. in China, a large amount of domestic oil-containing wastewater will also be generated. Since oil-containing wastewater pollutes the environment, affects the ecological balance, and has a great impact on the living environment of human beings, therefore, the treatment of oil-containing wastewater has important significance for environmental protection and sustainable development of human beings.

[0005] In the prior art, the methods for oil-water separation include gravity separation method, oxidation-reduction method, electrolysis method, chemical flocculation method, microbial degradation method and membrane filtration method, etc. Among them, the gravity separation method utilizes the density difference between oil and water to make oil droplets gradually gather and float in the sedimentation tank, which has low treatment efficiency, poor effect, large land occupation, and cannot treat oil-in-water or water-in-oil oil-containing emulsion; the oxidation-reduction method needs to consume oxidizing agents or reducing agents, the chemical flocculation method needs to consume flocculants, and the electrolysis method needs to consume a large amount of energy, so the treatment cost is relatively high; the microbial degradation method needs suitable microbial species and breeding conditions, and has limited application range, high cost and difficulty. Some of these methods have low treatment efficiency and poor effect, some need a large amount of consumables or energy, have high cost and are not conducive to environmental protection. Moreover, most of the oil-containing wastewater contains solid particles, and the existing treatment methods often need to add an additional process for treating solid particles, further increasing the treatment time and cost.

[0006] The membrane filtration method utilizes the micro-holes on the filter material, the substances with small particle size in the oil-containing wastewater can pass through the membrane, while the substances with large particle size are intercepted, and the membrane with appropriate pore size can achieve the purpose of oil-water separation, but the flux is low, and the membrane is easy to be clogged due to the adhesion of the intercepted oil on the surface of the membrane, which is not easy to clean, often needs to be replaced, has low reuse rate, increases the use cost, and the discarded membrane also needs high treatment cost.

[0007] In many cases, in addition to oil droplets of various particle sizes, the oily wastewater may also contain solid particles, and the oil-water separation methods in the prior art are generally difficult to simultaneously achieve solid particle filtration and oil-water separation, and there is an urgent need for a material suitable for treating oily wastewater containing solid particles. SUMMARY

[0008] An object of the present application is to provide a whisker-reinforced double-layer porous ceramic plate and a preparation method thereof, to solve the problem that the existing oil-water separation technology is difficult to be applied to the treatment of oily wastewater containing solid particles.

[0009] To achieve the above object, in a first aspect, the present application provides a whisker-reinforced double-layer porous ceramic plate, comprising an interception layer and a support layer, the interception layer having through holes, the thickness of the interception layer being 45-120 μm, the support layer having a cavity structure, the through holes of the interception layer being in communication with the cavity structure, the through holes of the interception layer and the whiskers having a reticular structure in the cavity structure, the through air porosity of the whisker-reinforced double-layer porous ceramic plate being greater than 50%.

[0010] Further, the through air porosity of the double-layer porous ceramic plate is 54%-80%.

[0011] In some embodiments, the proportion of the through holes in the interception layer having a pore size greater than a preset filtration pore size to the number of through holes having a pore size greater than 5 μm is less than 20%.

[0012] Further, the whiskers are silica whiskers, and the diameter of the whiskers is 50-150 nm.

[0013] In some embodiments, the thickness of the support layer is 8-32 mm.

[0014] In some embodiments, the outer surface layer and the internal pore surface layer of the whisker-reinforced double-layer porous ceramic plate have a hydrophilic film layer.

[0015] Further, the hydrophilic film layer is an amphoteric fluorocarbon surfactant.

[0016] In some embodiments, the cavity structure of the support layer is formed using a foaming process.

[0017] In some embodiments, the whisker-reinforced double-layer porous ceramic plate is prepared using quartz powder.

[0018] In a second aspect, the present application provides a method for preparing a whisker-reinforced double-layer porous ceramic plate, comprising the following steps: S1, mixing and stirring a main material including a first ceramic powder, a single-crystal silicon powder and water, a glue and a dispersant to form a first mixed slurry, the first ceramic powder having a silica content of ≥70%; S2, adding a foaming agent to the first mixed slurry and stirring to form a foamed slurry; S3, injecting the foamed slurry into at least one oil paper-covered mold, and taking out a ceramic rough after natural drying, wherein the contact surface between the ceramic rough and the oil paper forms an interception layer; S4, filling the interception layer of the ceramic rough with a dry second ceramic powder to form a ceramic blank; S5, using a carbon-embedded sintering method to embed the ceramic blank into carbon for sintering, with a temperature rising rate of 4-10℃ / min to 1000-1200℃, and keeping the temperature for more than 1 hour, to obtain a whisker-reinforced double-layer porous ceramic plate, wherein the main material has a mass percentage of 23-60% of the first ceramic powder, 10-15% of the single-crystal silicon powder, and 25-67% of water, and the glue, the dispersant and the foaming agent have a total mass percentage of 0.3-2% of the main material.

[0019] Further, after the temperature keeping step of step S5, the method further comprises the following step: S6, soaking the sintered ceramic blank in an amphoteric fluorocarbon surfactant solution, and taking out and drying to obtain a whisker-reinforced double-layer porous ceramic plate, wherein the concentration of the amphoteric fluorocarbon surfactant solution is 5%-8%.

[0020] In some preferred embodiments, the main material has a mass percentage of 38-50% of the first ceramic powder, 10-12% of the single-crystal silicon powder, and 38-52% of water, and the glue, the dispersant and the foaming agent have a total mass percentage of 1-2%, 1-2% and 0.3-1% of the main material, respectively.

[0021] In some embodiments, the first ceramic powder has a mesh number of 200-500 mesh. In some embodiments, the single-crystal silicon powder has a silicon content of ≥95%, and the single-crystal silicon powder has a mesh number of 200-500 mesh. In some embodiments, the first ceramic powder is any one or more of quartz, diatomite and silica, and the second ceramic powder is any one or more of quartz, diatomite, silica, mullite, kaolin and meerschaum.

[0022] Preferably, the first ceramic powder and the second ceramic powder are both quartz.

[0023] In some embodiments, the glue is any one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, xanthan gum and gelatin.

[0024] In some embodiments, the foaming agent is any one or more of sodium dodecyl sulfate, sodium dodecylaminopropionate, triethanolamine lauryl sulfate and a carbonate.

[0025] In some embodiments, the dispersant is any one or more of polyvinyl alcohol, polyvinyl alcohol copolymer, modified starch, silicone polyether emulsion.

[0026] In a third aspect, the present application provides a whisker-reinforced double-layer porous ceramic plate prepared by the above method.

[0027] In a fourth aspect, the present application also provides an application of the whisker-reinforced double-layer porous ceramic plate in oil-water separation containing solid particles.

[0028] The whisker-reinforced double-layer porous ceramic plate is prepared by using the first ceramic powder, the single crystal silicon powder and water as the main materials, using the oil paper on the surface of the mold for molding, further filling the pores on the surface of the ceramic rough blank with dry powder, burying the prepared ceramic blank in carbon for calcination, and then soaking in the amphoteric fluorocarbon surfactant solution, so as to prepare the whisker-reinforced double-layer porous ceramic plate containing the interception layer and the support layer.

[0029] The whisker-reinforced double-layer porous ceramic plate prepared by the method has the following characteristics: including the interception layer and the support layer, the thickness of the interception layer is extremely thin, which is equivalent to the particle size of the ceramic powder, and the number of through holes with a pore size larger than the preset filter pore size is extremely small; the support layer has a cavity structure including a large number of voids, and the cavity structure has a network structure of whiskers.

[0030] When the whisker-reinforced double-layer porous ceramic plate is applied to oil-water separation containing solid particles, the interception layer can first intercept a large number of oil droplets with large particle sizes, and the small pore size through holes of the interception layer can intercept solid particles with a particle size larger than the pore size of the through hole. Since the network whiskers in the cavity structure of the support layer also have hydrophilic and oleophobic properties, the oil-containing emulsion that is not intercepted passes through the through hole of the interception layer into the support layer, is divided into small water droplets and small oil droplets by the whiskers, and the water passes through smoothly, while the small oil droplets are retained in the cavity of the support layer. After a period of use, the solid particles clogging the through holes of the interception layer and the oil accumulated in the cavity of the support layer can be removed by backwashing technology to restore the filtration flux. Therefore, the whisker-reinforced double-layer porous ceramic plate of the present application can effectively treat the oil-containing wastewater containing solid particles and remove the solid particles and oil therein.

[0031] In addition, by further selecting quartz ceramic powder as the base material, the whisker-reinforced double-layer porous ceramic plate prepared has the characteristics of stable physical properties and is not easy to expand, so that the present application is suitable for large-scale industrial application.

[0032] The above summary of the present application is provided simply to reveal a general overview of the application and can not necessarily be comprised of all of the details of the application. Therefore, those skilled in the art will recognize that the summary of the present application is merely illustrative and is not intended to be limiting as to the scope of the application. BRIEF DESCRIPTION OF DRAWINGS

[0033] The above and other features of the present application will become more fully understood from the following detailed description and the accompanying drawings. It is to be understood that the application can assume various alternative embodiments, and, unless otherwise specified, the application can assume alternative steps and / or order of steps. Those skilled in the art will recognize that the application can comprise various alternative or equivalent implementations, and that the drawings and the associated descriptions are illustrative. It will further be understood that the terms "comprises" and / or "comprising", or "includes" and / or "including" when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0034] FIG. 1 shows a schematic view of the formation of pores by two-dimensional arrangement of a plurality of first ceramic powder particles 10;

[0035] FIG. 2 shows a photograph taken when observing the surface of the intercept layer of a ceramic green body prepared in step S3 using a magnifying glass;

[0036] FIG. 3 shows a schematic view of the filling of the pores of the intercept layer of the ceramic green body shown in FIG. 1 using a second ceramic powder 20 according to step S4;

[0037] FIG. 4 shows a photograph taken when observing the surface of the intercept layer of a ceramic green body prepared in step S4 using a magnifying glass;

[0038] FIG. 5 shows an SEM photograph of a cross-section of a whisker-reinforced double-layered porous ceramic plate prepared in Example B2, perpendicular to the intercept layer;

[0039] FIG. 6 shows an SEM photograph of a cross-section of a whisker-reinforced double-layered porous ceramic plate prepared in Example B2, parallel to the support layer of the intercept layer;

[0040] FIG. 7 shows a whisker-reinforced double-layered porous ceramic plate sample prepared in Example B2;

[0041] FIG. 8 shows the contact angle of oil with the whisker-reinforced double-layered porous ceramic plate sample in FIG. 7;

[0042] FIG. 9 shows a comparison of the whisker-reinforced double-layered porous ceramic plate sample in FIG. 7 before and after filtering oil-containing wastewater;

[0043] FIG. 10 shows the filtration flux of a whisker-reinforced double-layered porous ceramic plate prepared in Example Al in filtering oil-containing wastewater generated by a cold-rolled galvanized line in a steel plant;

[0044] FIG. 11 shows a comparison of a whisker-reinforced porous ceramic plate sample prepared in Example Dl before and after filtering oil-containing wastewater;

[0045] Figure 12 shows a comparison chart of pure water flux test using the whisker reinforced porous ceramic plate prepared by Example D1 and Example D2. DETAILED DESCRIPTION

[0046] The technical solutions of the present application are described in detail below with reference to the accompanying drawings. Other embodiments can be adopted and modifications, combinations, equivalent replacements or other changes can be made without departing from the spirit or scope of the subject matter of the present application, and all of these are explicitly part of the content of the present application and included in the protection scope of the present application.

[0047] The method for preparing the whisker reinforced double-layer porous ceramic plate of the present application comprises steps S1-S5, wherein the step S1 and step S2 are used for making a foam slurry, the raw materials of the foam slurry include main materials and auxiliary materials, the main materials are as follows in percentage by mass: first ceramic powder 23-60%, monocrystalline silicon powder 10-15%, water 25-67%, the auxiliary materials include adhesive, dispersant and foaming agent, all of which are 0.3-2% of the total mass of the main materials; preferably, the first ceramic powder is 38-50%, the monocrystalline silicon powder is 10-12%, the water is 38-52%, the adhesive, the dispersant and the foaming agent are respectively 1-2%, 1-2% and 0.3-1% of the total mass of the main materials. The steps S1-S6 are specifically as follows:

[0048] S1, the main materials including the first ceramic powder, the monocrystalline silicon powder and the water are stirred and mixed with the adhesive and the dispersant to form a first mixed slurry.

[0049] The first ceramic powder can be any one or more of quartz, diatomite and silica stone. In some embodiments, the quartz powder is preferred; further, in order to reduce the cost, waste quartz with a silica content of ≥70% can be selected. The mesh number of the first ceramic powder can be selected to be between 200-500 mesh.

[0050] The monocrystalline silicon powder has a silicon content of ≥95% and a mesh number of 200-500 mesh. The inventors of the present application found that the addition of the monocrystalline silicon powder can participate in the reaction and induce the growth of silica whiskers in the subsequent step of burying in carbon and roasting. The addition of only the first ceramic powder with a silica content of ≥70% or only the monocrystalline silicon powder cannot form whiskers, and the synergistic effect of both is necessary.

[0051] The adhesive is any one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, xanthan gum and gelatin, which is used to provide viscosity to the slurry.

[0052] The dispersant can be any one or more of polyvinyl alcohol, polyvinyl alcohol copolymer, modified starch, silicone polyether emulsion, and the like, and can uniformly disperse the first ceramic powder and the monocrystalline silicon powder in water. Meanwhile, the dispersant also has a foam stabilizing effect, and pre-adding the dispersant can make the bubbles in the foam slurry of step S2 more persistent and stable.

[0053] The stirring and mixing time can be more than 10 minutes.

[0054] S2, adding a foaming agent to the first mixed slurry and stirring and mixing to form a foam slurry.

[0055] The foaming agent can be any one or more of sodium dodecyl sulfate (K12), sodium dodecyl amino propionate, triethanolamine lauryl sulfate (TD-40), and carbonates, and after adding the foaming agent, air can be mixed into the slurry to form a foam slurry during stirring.

[0056] The stirring and mixing time can be more than 5 minutes, and is preferably 5-10 minutes.

[0057] S3, injecting the foam slurry into at least one mold covered with oil paper, and taking out the ceramic rough after natural drying.

[0058] The shape of the mold can be determined according to the shape of the ceramic rough needed, and the oil paper is a kind of processing paper made by applying tung oil or other drying oil on a flexible surface. The oil paper is used to cover at least one surface of the mold, such as the bottom surface and / or the side surface of the mold, and the surface coated with the drying oil faces outward.

[0059] In the prior art, isolation paper is usually used on the surface of the mold to separate the mold and the ceramic rough. Although the ordinary isolation paper can separate the ceramic rough and the mold, it is easy to stick to the ceramic powder particles.

[0060] In this step, by using oil paper on the surface of the mold, on one hand, the ceramic slurry can be prevented from sticking to the surface of the mold, and after the slurry is dried, the ceramic green body can be easily taken out of the mold. On the other hand, the inventors of the present application found that after the foamed slurry is injected into the mold with the surface covered with oil paper, the ceramic powder particles close to the oil paper are arranged in a two-dimensional manner, forming an extremely thin surface layer with a thickness of about 1-2 times the particle size of the ceramic powder. For example, if the first ceramic powder is 200-500 mesh, an interception layer with a thickness of about 45-120 μm can be formed. At the same time, due to the irregular shape of the ceramic powder, there are pores between the ceramic powder particles close to the oil paper. In addition, due to the existence of bubbles in the foamed slurry, the bubbles close to the oil paper make the surface layer have a large number of pores, some of which are even visible to the naked eye. Figure 1 shows a schematic diagram of a plurality of first ceramic powder particles 10 forming pores by two-dimensional arrangement. For the sake of convenience, these pores can be divided into small-size pores 11 and large-size pores 12. There is no clear dividing line between the small-size pores 11 and the large-size pores 12, and they can be divided according to the needs of filtration. For example, if it is desired to intercept solid particles with a pore size greater than 50 μm, pores with a pore size less than 50 μm can be referred to as small-size pores, and pores with a pore size greater than 50 μm can be referred to as large-size pores.

[0061] The small-size pores 11 are suitable for intercepting solid particles with a size greater than the pore size of these pores, so the present application refers to the extremely thin surface layer formed by the ceramic powder close to the oil paper as an interception layer, and the pores formed between the ceramic powder particles on the interception layer as through holes passing through the interception layer. The prior art uses ordinary release paper, and due to the easy adhesion of the release paper to the ceramic powder particles, it is not possible to form a two-dimensional arrangement of ceramic powder particles on the contact surface between the ceramic slurry and the release paper.

[0062] The part of the ceramic green body other than the interception layer is referred to as the support layer. Unlike the interception layer, the ceramic powder particles in the support layer are connected in a three-dimensional stacking manner, and due to the action of the foaming agent, a large number of cavity structures are formed in the inside of the support layer. The thickness of the support layer can be controlled by setting the depth of the mold.

[0063] The through holes of the interception layer and the cavities of the support layer are in communication with each other, forming through holes passing through the interception layer and the support layer.

[0064] In order to fully dry the ceramic green body, in some embodiments, the natural drying time is more than 48 hours. In some embodiments, after natural drying, the temperature can be raised to 50-100°C for continuous drying for more than 3 hours.

[0065] Figure 2 shows a photograph taken when observing the surface of the interception layer of a ceramic green body prepared in step S3 using a magnifying glass. As can be seen from the figure, a plurality of large-size pores visible to the naked eye are present, and some of the large-size pores are marked with dashed circles in the figure.

[0066] S4, filling the pores of the interception layer of the ceramic rough with dry powder of the second ceramic powder to form a ceramic blank.

[0067] The second ceramic powder can be selected from any one or more of quartz, diatomite, silica, mullite, kaolin, sepiolite, dolomite. The second ceramic powder can be the same as the first ceramic powder or different from the first ceramic powder. For example, in some embodiments, the first ceramic powder is quartz and the second ceramic powder is also quartz.

[0068] Step S4 can fill the pores of the interception layer of the ceramic rough with a pore size larger than the particle size of the second ceramic powder with the second ceramic powder, thereby reducing the proportion of large-pore through holes. Therefore, the particle size of the second ceramic powder can be selected according to the needs of filtration, i.e. according to the size of the preset filtration pore size. For example, if it is desired that the interception layer can intercept solid particles with a particle size greater than 50 μm, a second ceramic powder with a particle size slightly smaller than 50 μm can be used, for example, a second ceramic powder that can pass through a 300 mesh sieve but cannot pass through a 350 mesh sieve. If the particle size of the second ceramic powder is much smaller than 50 μm, it can cause excessive filling of the pores of the interception layer and severely reduce its flux. Figure 3 shows a schematic diagram of the interception layer of the ceramic rough shown in Figure 1 after the pore filling step S4 using the second ceramic powder 20. The effect of the second ceramic powder on the filling of large-size pores 12 is shown in the figure.

[0069] Step S4 can be implemented in the following way. First, dry powder of the second ceramic powder is applied to the interception layer of the ceramic rough, and then the surface of the interception layer is swept with a brush. The purpose of sweeping is to remove the second ceramic powder particles that fall outside the pores of the interception layer, while retaining the second ceramic powder particles that fall into the pores of the interception layer. In general, the more dry powder of the second ceramic powder is applied, the more uniform the sweeping, and the more fully the second ceramic powder particles can cover the through holes with a pore size larger than the particle size of the second ceramic powder, thereby reducing the proportion of large-size through holes that do not meet the filtration requirements. By appropriate application, the proportion of through holes with a pore size larger than the particle size of the second ceramic powder particles in the number of through holes with a pore size larger than 5 μm can be lower than a preset value, for example, lower than 20%, 10%, 5%, etc. In the case of sufficient application, this proportion can even be lower than 1%.

[0070] Figure 4 shows a photograph taken when observing the surface of the interception layer of a ceramic blank prepared in step S4 using a magnifying glass. In the figure, the second ceramic powder is white quartz. As can be seen from the figure, after the pore filling step, most of the large-size pores are filled with second ceramic powder particles.

[0071] S5, using carbon-embedding sintering method to embed the ceramic green material into carbon for baking, heating to 1000-1200℃ at a heating rate of 4-10℃ / min, keeping temperature for more than 1 hour, to obtain the whisker-reinforced double-layer porous ceramic plate.

[0072] The carbon-embedding sintering method is a method of embedding the ceramic green material into carbon and baking the ceramic material in an isolated state. Since a small amount of oxygen is left between the carbon and the ceramic green material, the carbon reacts with the oxygen at high temperature, and then reacts with part of the silicon dioxide in the first ceramic powder to produce gaseous silicon monoxide. At the same time, the single crystal silicon powder also reacts with the silicon dioxide and oxygen in the first ceramic powder to produce gaseous silicon monoxide. Since gaseous silicon monoxide cannot exist stably below 1500℃, it is decomposed by gas deposition to form a network structure of silicon dioxide whiskers in the cavity structure of the support layer. A relatively small amount of network structure whiskers is also formed on the surface and / or in the pores of the interception layer. The diameter of the whiskers is generally 50-150nm.

[0073] At the same time, the ceramic powder particles are fused together to form a ceramic material with good mechanical strength, and the network of whiskers in the cavity of the support layer can further enhance the mechanical strength.

[0074] In order to further enhance the hydrophilic and oleophobic properties of the double-layer porous ceramic plate, after the temperature keeping step of step S5, the method for preparing the whisker-reinforced double-layer porous ceramic plate of the present application comprises step S6:

[0075] S6, soaking the baked ceramic green material in an amphoteric fluorocarbon surfactant solution, and drying after taking out, to obtain the whisker-reinforced double-layer porous ceramic plate.

[0076] The amphoteric fluorocarbon surfactant is a surfactant with a fluorocarbon chain as a non-polar group, which can act as an anionic surfactant or a cationic surfactant. The amphoteric fluorocarbon surfactant can significantly reduce the surface tension at a very low concentration and enhance the hydrophilicity of the surface. In this step, various amphoteric fluorocarbon surfactants that can enhance hydrophilicity can be used, such as Yunqing Chemical RK-8410 and DuPont KEMFO FS-50. Generally, a concentration of 5-8% is used, and the soaking time can be more than one hour. Soaking the whisker-reinforced ceramic green material in the amphoteric fluorocarbon surfactant solution can form a hydrophilic film layer on the outer surface layer and the internal pore surface layer of the whisker-reinforced ceramic green material, significantly reduce the surface tension, and enhance the hydrophilic and oleophobic ability.

[0077] The whisker-reinforced double-layer porous ceramic plate prepared by the above method has a double-layer structure including an interception layer and a support layer, the surface of the interception layer has through-holes with small pore diameters, and the support layer has a cavity structure generated by a foaming process. The through-holes of the interception layer and the cavities of the support layer are in communication with each other, forming through-holes penetrating through the interception layer and the support layer. The interception layer through-holes and the whiskers with a reticular structure in the cavity structure. The outer surface layer and the internal pore surface layer of the whisker-reinforced double-layer porous ceramic plate also have a hydrophilic film layer composed of an amphoteric fluorocarbon surfactant. In the present disclosure, the foaming process refers to a process step of adding a foaming agent to the ceramic slurry during the preparation of the ceramic material to form a cavity structure in the ceramic material.

[0078] It should be noted that in the present disclosure, the mesh number of the ceramic powder or the single crystal silicon powder refers to that the ceramic powder or the single crystal silicon powder can pass through the screen with the corresponding mesh number. In the present disclosure, the correspondence between the mesh number of the screen and the pore diameter of the screen is shown in the following table:

[0079] Figure 5 shows the SEM photo of the whisker-reinforced double-layer porous ceramic plate prepared in Example B2 of the second group of embodiments of the present disclosure, which is perpendicular to the section of the interception layer. The interception 1 and the support layer 2 are exemplarily shown in the figure, the interception layer 1 has an extremely thin thickness h, and a large number of cavity structures can be seen in the support layer 2.

[0080] Figure 6 shows the SEM photo of the support layer section parallel to the interception layer of the whisker-reinforced double-layer porous ceramic plate prepared in Example B2, from which it can be seen that after being magnified to a sufficient multiple, the dense reticular structure whiskers in the cavity structure of the support layer are clearly visible.

[0081] When the whisker-reinforced double-layer porous ceramic plate is used for the treatment of oily sewage containing solid particles, the sewage flows through the interception layer, and large oil droplets and solid particles with a particle size larger than the pore diameter of the interception layer are first blocked by the interception layer. Since the surface of the interception layer is coated with a hydrophilic and oleophobic material, the oil droplets float after being intercepted, and the solid particles sink after being intercepted. The solid particles and the oil-water mixture that are not intercepted pass through the through-holes on the surface of the interception layer into the support layer. Since the thickness of the interception layer is very thin, the small-pore-diameter through-holes of the interception layer quickly transition to the large-pore-diameter cavities of the support layer, so that the small-particle-size solid particles that are not intercepted can smoothly pass through the support layer and are not prone to be blocked. Since the cavities have dense reticular whiskers, the oil-water mixture entering the support layer is cut into many small water droplets and small oil droplets by these reticular whiskers, thereby separating the oil and water in the oil-containing emulsion. In addition, due to the hydrophilic film layer of the internal pore surface layer, a water film is formed on the internal pore surface layer, further blocking the small oil droplets from adhering to the pore surface layer, and the small oil droplets will accumulate in the cavities of the support layer.

[0082] With the increase of use time, the interception layer part of the hole may be blocked by large size solid particles or oil droplets, resulting in a decrease in filtration flux. In addition, the oil droplets accumulated in the support layer need to be removed to reduce the mixing into the filtered water. At this time, the whisker reinforced double-layer porous ceramic plate support layer of the present disclosure has a large size cavity, and the interception layer hole has a small aperture structure. The backwashing technology is used to flush off the solid particles or oil droplets attached to the interception layer hole, and at the same time, the oil accumulated in the support layer is removed, thereby restoring the filtration capacity of the whisker reinforced double-layer porous ceramic plate. The specific process of backwashing is as follows: using a liquid pump or a gas pump, hydraulic pressure or air pressure is applied from the support layer to the interception layer direction, so that the oil droplets accumulated in the support layer are blown out from the interception layer hole in the opposite direction and removed, and at the same time, the solid particles or oil droplets attached to the interception layer hole are detached due to the pressure difference. The backwashing time can be set comprehensively according to factors such as the distribution of solid particles in sewage, the oil content, and the thickness of the support layer. If the distribution of solid particles is not considered, in general, in the case of a fixed support layer thickness, the higher the oil content, the more oil droplets the support layer can accumulate in a unit of time, and in order to remove the oil in time, the shorter the backwashing interval. In the case of a fixed oil content, the thicker the support layer, the more oil droplets the support layer can accumulate in a unit of time, and the longer the backwashing interval. In actual use, it can be started at a certain time interval, or started according to the decrease of the oil-water separation flux to a preset value, or started according to the decrease of the separation efficiency to a preset threshold.

[0083] The whisker reinforced double-layer porous ceramic plate and the preparation method and application effect thereof of the present application will be further described below in conjunction with examples.

[0084] In the present disclosure, the aperture distribution of the interception layer hole is counted by direct observation of the section, that is, by counting the number of different size holes with an aperture greater than 5 μm per unit area based on the SEM photo of the interception layer of the whisker reinforced double-layer porous ceramic plate. Since the hole is irregular in shape, the aperture of the hole is defined as the average of the diameter of the inscribed circle and the diameter of the circumscribed circle.

[0085] To clearly illustrate the structure of the whisker-reinforced double-layer porous ceramic plate of the present disclosure, the thickness of the interception layer needs to be further measured. The thickness of the interception layer can be intuitively understood as the shortest distance from the outer surface of the interception layer to the cavity of the support layer. However, due to the randomness of the foaming process, the shape of the bubble structure of the support layer has irregularity, and therefore, the distance from different areas of the outer surface of the interception layer to the nearest cavity of the support layer can be different. Therefore, in the present disclosure, the thickness of the interception layer of the structure of the whisker-reinforced double-layer porous ceramic plate can be represented by an interval. The thickness of the interception layer can be measured by taking SEM photos of the cross section of the whisker-reinforced double-layer porous ceramic plate perpendicular to the interception layer. The specific measurement process is as follows: select several measurement points on the outer surface of the interception layer. For each selected measurement point, along the direction perpendicular to the outer surface of the interception layer towards the support layer, the distance to the interception layer aperture when the aperture diameter reaches a preset filtration pore size is the thickness of the interception layer in the area where the measurement point is located. A certain statistical quantity of the thickness of the interception layer measured by multiple measurement points can be used as the measurement of the thickness of the interception layer of the whisker-reinforced double-layer porous ceramic plate, for example, the statistical quantity can be the average value, or the median value, or the average value or median value after removing the maximum value and the minimum value of the thickness of the interception layer measured by multiple measurement points. Those skilled in the art can understand that the positions of the selected measurement points should be as dispersed as possible, and the number of measurement points should be as large as possible, in order to obtain a higher reliability of the thickness range of the interception layer. In the present disclosure, the average value after removing the maximum value and the minimum value is used as the measurement of the thickness of the interception layer of the whisker-reinforced double-layer porous ceramic plate. In the present disclosure, the preset filtration pore size can be set as needed, for example, if it is desired that the interception layer can intercept solid particles with a particle size greater than 50 μm, the preset filtration pore size is 50 μm.

[0086] In the present disclosure, the through-pore rate refers to the ratio of the total volume of the through holes that are mutually through with the outside to the volume of the ceramic material, which can be measured in the following way: (1) immerse the ceramic material to be measured in a liquid, and measure the increase in the volume of the liquid ΔV; (2) calculate the volume Vo of the ceramic material to be measured according to its external dimensions. Then the through-pore rate η of the ceramic material to be measured is (Vo-ΔV) / Vo. Those skilled in the art can understand that, in the case of the same aperture size distribution of the interception layer through holes, in general, the higher the through-pore rate, the larger the volume occupied by the cavities of the support layer, and the less likely to be blocked. The whisker-reinforced double-layer porous ceramic plate of the present disclosure is prepared by foaming process, and its through-pore rate is generally greater than 50%, which is related to the amount of foaming agent, stirring time and other parameters, and different through-pore rates can be obtained by changing the relevant parameters. The method of the present disclosure can be used to prepare a whisker-reinforced double-layer porous ceramic plate with a through-pore rate of 50%-80%.

[0087] The support layer is used to divide the oil-containing emulsion into many small water droplets and small oil droplets, and to block the small oil droplets from passing through the support layer. In addition, the support layer is further used to accommodate the separated oil droplets so that the oil droplets are subsequently blown out through the interception layer via the backwashing technology. Therefore, the support layer needs a certain thickness to prevent the oil droplets from passing through, to accommodate the oil droplets intercepted by the reticular whiskers, and to maintain a certain mechanical strength, and thus the thickness of the support layer is generally set to be greater than 8 mm. Preferably, the thickness of the support layer is set to be in the range of 8-32 mm.

[0088] The present disclosure is further illustrated by the following examples. For the convenience of understanding, the examples of preparing the whisker-reinforced double-layer porous ceramic plate using the method of the present disclosure are divided into three groups, and each example uses steps S1-S6, with the difference being different materials and parameters. The specific steps of each example are as follows: S1, the main materials including the first ceramic powder, the single crystal silicon powder and water are stirred and mixed with the adhesive and the dispersing agent at a stirring rate of 3000 rpm for 45 minutes to form a first mixed slurry; S2, the foaming agent is added to the first mixed slurry and stirred at a stirring rate of 3000 rpm for 10 minutes to form a foamed slurry; S3, the foamed slurry is injected into a circular mold with an oil paper attached to the bottom, and the ceramic green body is taken out after natural drying for 60 hours and further drying at a temperature of 50-100℃ for 3 hours; S4, the interception layer of the ceramic green body is filled with the dry powder of the second ceramic powder to form a ceramic blank; S5, the ceramic blank is buried in carbon with a thickness of twice that of the ceramic blank, and is fired at a temperature increasing rate of 4-10℃ / min to 1200℃, and is kept at the temperature for 3 hours to obtain a whisker-reinforced ceramic blank; S6, the whisker-reinforced ceramic blank is soaked in an amphoteric fluorocarbon surfactant solution for 1 hour, and is dried after being taken out to obtain a whisker-reinforced double-layer porous ceramic plate. Here, the amphoteric fluorocarbon surfactant solution is a 5% Dupont Kermel FS-50 aqueous solution. FS-50 aqueous solution, FS-50 is a kind of amphoteric fluorocarbon surfactant, and soaking in its aqueous solution can form a hydrophilic film layer on the outer surface layer and the internal pore surface layer of the ceramic blank.

[0089] In the examples of the present disclosure, the preset interception pore size is 50μm, and therefore the second ceramic powder uses quartz powder with a particle size slightly smaller than 50μm. Those skilled in the art can select a second ceramic powder with a suitable particle size according to different preset interception pore sizes.

[0090] The first group of embodiments includes embodiments A1-A3. In embodiment A1, the main materials are first ceramic powder 38%, single crystal silicon powder 12%, and water 50% by mass percentage, and the auxiliary materials include adhesive 1%, dispersant 1%, and foaming agent 0.7% by mass percentage of the total mass of the main materials. The first ceramic powder is quartz powder with a silica content of 95% and a mesh size of 200, the single crystal silicon powder has a silicon content of 95% and a mesh size of 200, the adhesive is sodium cellulose, the dispersant is polyvinyl alcohol copolymer, and the foaming agent is triethanolamine lauryl sulfate (TD-40).

[0091] Embodiments A2-A3 of the whisker-reinforced double-layer porous ceramic plate differ from embodiment A1 in the mesh size of the first ceramic powder, the mass percentage of single crystal silicon, and the mass percentage of water, and other process parameters are the same. The specific parameters and experimental results are shown in Table 1-1 and Table 1-2.

[0092] Table 1-1 Parameters of the first group of embodiments

[0093] Table 1-2 Experimental results of the first group of embodiments

[0094] In this group of embodiments and subsequent embodiments, the proportion of through holes with a pore size greater than 50 μm in the interception layer refers to the proportion of through holes with a pore size greater than 50 μm in the number of through holes with a pore size greater than 5 μm in the interception layer. The thickness of the interception layer is obtained by selecting 10 measurement points at intervals of 1 mm along the direction of the interception layer from the SEM photos of the cross section of the whisker-reinforced double-layer porous ceramic plate perpendicular to the interception layer, measuring the thickness of the interception layer at each measurement point, and then taking the average of the thicknesses of the remaining 8 measurement points after removing the maximum and minimum values.

[0095] In this disclosure, the separation efficiency is defined as the ratio of the difference between the Total Organic Carbon (TOC) of the sewage before filtration and the TOC of the sewage after filtration to the TOC before filtration, expressed in percentage. The total organic carbon is expressed as the total amount of organic matter in water in terms of carbon content, expressed as the mass concentration of carbon (C) (mg / L). The higher the TOC value of water, the higher the content of organic matter in water, therefore, TOC can be used as an indicator to evaluate the organic pollution of water quality. The organic matter in oil-containing sewage is mainly oil, therefore, the separation efficiency defined by the above method can reflect the effect of oil-water separation.

[0096] The oil contact angle refers to the angle between the tangent of the air-oil droplet interface and the oil droplet-support layer cross section intersection line at the three-phase intersection point of air, oil droplet, and support layer cross section, the larger the angle, the worse the wettability of oil on the solid surface, and the stronger the oleophobicity of the experimental product.

[0097] The results of the first group of embodiments show that as the mesh number of the first ceramic powder and the single crystal silicon powder increases, the through-pore rate increases, the separation efficiency increases, and the oil contact angle also increases. It can be seen that the larger the mesh number of the first ceramic powder and the single crystal silicon powder, the better the effect, but too high mesh number will reduce the mechanical strength and affect the service life. As the mass percentage of the single crystal silicon powder increases, the through-pore rate decreases, the separation efficiency increases, and the oil contact angle decreases. In the case of the same mesh number of the first ceramic powder, the thickness of the interception layer is not much different.

[0098] The second group of embodiments includes embodiments B1-B3. In embodiment B1, the main materials are first ceramic powder 50%, single crystal silicon powder 12%, and water 38% by mass percentage, and the auxiliary materials include 1% of a glue agent, 1% of a dispersing agent, and 0.7% of a foaming agent based on the total mass of the main materials. The first ceramic powder is waste quartz powder with a silicon dioxide content of 80% and a mesh number of 325, which is beneficial to further reduce the cost; the single crystal silicon powder has a silicon content of 95% and a mesh number of 325; the glue agent is yellow glue, the dispersing agent is polyvinyl alcohol copolymer, and the foaming agent is sodium dodecyl sulfate (K12).

[0099] Embodiments B2-B3 differ from embodiment B1 in the mass percentage of the waste quartz powder and the mass percentage of water, and other process parameters are the same. The specific parameters and experimental results are shown in Table 2-1 and Table 2-2.

[0100] Table 2-1 Parameters of the second group of embodiments

[0101] Table 2-2 Experimental results of the second group of embodiments

[0102] The results of the second group of embodiments show that as the mass percentage of the first ceramic powder decreases, the through-pore rate increases, the separation efficiency decreases, and the oil contact angle fluctuates but is at a relatively high level overall. In the case of the same mesh number of the first ceramic powder, the thickness of the interception layer is not much different.

[0103] The third group of embodiments includes embodiments C1-C5. In embodiment C1, the main materials are first ceramic powder 40%, single crystal silicon powder 12%, and water 48% by mass percentage, and the auxiliary materials include 1% of a glue agent, 1% of a dispersing agent, and 0.7% of a foaming agent based on the total mass of the main materials. The first ceramic powder is diatomite powder with a silicon dioxide content of 82% and a mesh number of 325, the single crystal silicon powder has a silicon content of 95% and a mesh number of 325, the glue agent is yellow glue, the dispersing agent is polyvinyl alcohol copolymer, and the foaming agent is sodium dodecyl sulfate (K12).

[0104] The whisker-reinforced double-layer porous ceramic plate embodiments C2-C5 differ from embodiment CI in the mass percentage of the first ceramic powder, the mass percentage of the monocrystalline silicon, and the mass percentage of water, and other process parameters are the same. The specific parameters and experimental results are shown in Table 3-1 and Table 3-2.

[0105] Table 3-1 Parameters of the third group of embodiments

[0106] Table 3-2 Experimental results of the third group of embodiments

[0107] The results of the third group of embodiments show that as the mass percentage of the first ceramic powder decreases, the through-pore rate increases and the separation efficiency decreases. As the mass percentage of the monocrystalline silicon powder decreases, the through-pore rate increases and the separation efficiency decreases. When the mass percentage of the monocrystalline silicon powder is 9%, the separation efficiency decreases to below 90%. In the case of the same mesh number of the first ceramic powder, the thickness of the interception layer does not differ much.

[0108] Figure 7 shows a whisker-reinforced double-layer porous ceramic plate sample prepared using embodiment B2, which has a diameter of 240 mm, a thickness of 12 mm, and an effective membrane area of 0.045 square meters.

[0109] Figure 8 shows a schematic diagram of the contact angle between oil and the whisker-reinforced double-layer porous ceramic plate sample in Figure 7, and the contact angle is 132°.

[0110] Figure 9 shows a comparison between the oil-containing wastewater before and after filtration by the whisker-reinforced double-layer porous ceramic plate sample in Figure 7. In the figure, 0-3# on the left is the wastewater before filtration, 2-3# on the right is the wastewater after filtration, and 1-3# in the middle is the oil separated from the wastewater. As can be seen from the figure, before filtration, the wastewater is turbid and brown due to the presence of a large amount of solid particles and oil, and after filtration, the wastewater becomes clear. In this embodiment, the TOC of the wastewater before filtration is 15763 mg / L, and the TOC of the wastewater after filtration is 267.58 mg / L, with a separation efficiency of 98.3%.

[0111] Figure 10 shows a flux diagram of the treatment of oil-containing wastewater generated by a certain steel plant's cold-rolled galvanized line using the whisker-reinforced double-layer porous ceramic plate prepared in embodiment Al. In this embodiment, the oil content and solid particle content in the oil-containing wastewater change over time, and backwashing is performed when the filtration flux decreases to about 60% of the initial filtration flux, with a backwashing time of 5 seconds and a filtration flux measurement interval of 10 minutes. As can be seen from the figure, when the whisker-reinforced double-layer porous ceramic plate is used for filtration, the filtration flux decreases over time, but after backwashing, the filtration flux is restored.

[0112] The present disclosure also provides a method for preparing a whisker-reinforced porous ceramic plate, comprising the following steps:

[0113] S21, stirring and mixing the main material including the first ceramic powder, the single crystal silicon powder and water, the adhesive and the dispersant to form a first mixed slurry, the silica content of the first ceramic powder being ≥70%;

[0114] S22, stirring and mixing the first mixed slurry with the foaming agent to form a foaming slurry;

[0115] S23, injecting the foaming slurry into a mold, and taking out the ceramic blank after natural drying;

[0116] S24, using the carbon-embedded sintering method to embed the ceramic blank in carbon for baking, the temperature being raised to 1000-1200℃ at a temperature raising rate of 4-10℃ / min, and the temperature being kept for more than 1 hour to obtain the whisker-reinforced porous ceramic plate.

[0117] The whisker-reinforced porous ceramic plate prepared by the above method is different from the whisker-reinforced double-layer porous ceramic plate prepared by the method of the present disclosure only in that no oil paper is covered in the mold when the ceramic blank is prepared, no interception layer is formed, and therefore, the interception layer of the ceramic blank does not need to be filled with the second ceramic powder. The main material, the auxiliary material, the mass percentage, the mesh number and other technical features are the same as those in the above-mentioned method for preparing the whisker-reinforced double-layer porous ceramic plate.

[0118] The above preparation method does not cover the oil paper in the mold, and therefore, no interception layer is formed. The structure of the interception layer is the same as that of the support layer of the whisker-reinforced double-layer porous ceramic plate, has a cavity structure, and has the whiskers with a reticular structure in the cavity structure. The through-pore rate is greater than 50%, for example, can be 50%-80%.

[0119] In order to further improve the hydrophilicity and oleophobicity, after the temperature keeping step of step S24, the method further comprises step S25:

[0120] S25, soaking the whisker-reinforced ceramic blank obtained by baking in an amphoteric fluorocarbon surfactant solution, and taking out and drying to obtain the whisker-reinforced porous ceramic plate.

[0121] Through step S25, the outer surface layer and the inner pore surface layer of the whisker-reinforced double-layer porous ceramic plate have a hydrophilic film layer, and the hydrophilicity and oleophobicity are further improved.

[0122] The fourth group of embodiments includes embodiments D1 and D2. Each of the embodiments uses steps S21-S25, with the difference being the first ceramic powder. The specific steps of each embodiment are as follows: S21, mix the main materials including the first ceramic powder, the single crystal silicon powder, and water with the adhesive and the dispersant, at a stirring rate of 3000 rpm for 45 minutes, to form a first mixed slurry; S22, mix the first mixed slurry with the foaming agent, at a stirring rate of 3000 rpm for 10 minutes, to form a foamed slurry; S23, pour the foamed slurry into a circular mold, and naturally dry for 60 hours, then take out the ceramic green body after drying at a temperature of 50-100°C for 3 hours; S24, use the carbon-embedded sintering method to embed the ceramic green body in carbon that is twice as thick as the ceramic green body, and sinter at a temperature of 1200°C at a temperature increasing rate of 4-10°C / min, and keep the temperature for 3 hours, to obtain a whisker-reinforced ceramic green body; and S25, soak the whisker-reinforced ceramic green body in a 5% FS-50 aqueous solution for 1 hour, and then take out and dry, to obtain a whisker-reinforced porous ceramic plate. FS-50 aqueous solution for 1 hour, and then take out and dry, to obtain a whisker-reinforced porous ceramic plate.

[0123] Embodiment D1 is the invention, which is based on embodiment C4, and omits the steps of covering the surface of the mold with oil paper and filling the pores of the intercepting layer of the ceramic rough body with the second ceramic powder, and replaces the adhesive.

[0124] In embodiment D1, the main materials are as follows in terms of mass percentage: 38% of the first ceramic powder, 12% of the single crystal silicon powder, and 50% of water, and the auxiliary materials include 1% of the adhesive, 1% of the dispersant, and 0.7% of the foaming agent, based on the total mass of the main materials. The first ceramic powder is diatomaceous earth powder with a silicon dioxide content of 82% and a mesh number of 325, the single crystal silicon powder has a silicon content of 95% and a mesh number of 325, the adhesive is sodium cellulose, the dispersant is polyvinyl alcohol copolymer, and the foaming agent is sodium dodecyl sulfate (K12).

[0125] Embodiment D2 differs from embodiment D1 only in that the first ceramic powder is replaced by quartz with a silicon dioxide content of 95% and a mesh number of 325.

[0126] The specific parameters are shown in Table 4.

[0127] Table 4: Parameters of the fourth group of embodiments

[0128] Figure 11 shows the comparison of the oil-containing wastewater before and after filtration by the whisker-reinforced porous ceramic plate sample prepared in Example D1. The left side of the figure shows the wastewater before filtration, and the right side shows the wastewater after filtration. As can be seen from the figure, before filtration, the wastewater is turbid and yellow due to the presence of a large amount of solid particles and oil. After filtration, the color of the wastewater becomes lighter, and the transparency is improved. In this example, the TOC of the wastewater before filtration is 1157.43 mg / L, and the TOC of the wastewater after filtration is 268.096 mg / L, with a separation efficiency of 76.80%.

[0129] The inventors of the present disclosure further found through experiments that although the whisker-reinforced porous ceramic plates prepared using different ceramic powders have similarities in structure, the whisker-reinforced porous ceramic plates prepared using different ceramic powders have differences in service life due to the differences in the properties of different materials. Figure 12 shows the change in pure water flux over time under the same test conditions for the whisker-reinforced porous ceramic plates prepared using Example D1 and Example D2. As can be seen from the figure, the pure water flux of the whisker-reinforced porous ceramic plate prepared using diatomite rapidly decreases after more than 4 hours of use; while the pure water flux of the whisker-reinforced porous ceramic plate prepared using quartz remains stable even after more than 48 hours of use. Observation of the whisker-reinforced porous ceramic plates after use found that the whisker-reinforced porous ceramic plate prepared using diatomite swells after long-term soaking, causing the through holes to be blocked, thereby causing the water flux to decrease, while the whisker-reinforced porous ceramic plate prepared using quartz does not swell, thereby maintaining a stable flux for a long time.

[0130] Since the main difference between the whisker-reinforced double-layer porous ceramic plate and the whisker-reinforced porous ceramic plate is that the former has an interception layer, it can be understood that the whisker-reinforced double-layer porous ceramic plate prepared using diatomite will also swell after a period of use, while the whisker-reinforced double-layer porous ceramic plate prepared using quartz will not swell even after a long period of use, and the physical properties are stable.

[0131] The method for preparing the whisker-reinforced double-layer porous ceramic plate of the present disclosure uses a first ceramic powder with a silica content of ≥70%, a single-crystal silicon powder, and water as the main materials, and forms an extremely thin surface layer with pores, i.e., an interception layer, and a support layer with a cavity structure having a large number of voids on the surface of the prepared ceramic rough blank by using oil paper to prepare the blank on the surface of the mold based on the foamed ceramic process, and then buries the prepared ceramic blank in carbon and reacts with it to generate whiskers in a network structure inside the cavity structure. The whisker-reinforced double-layer porous ceramic plate prepared by this method has high separation efficiency when used to filter wastewater containing solid particles and oil, has good filtration effect on solid particles, and is not prone to blockage.

[0132] On the basis of the prepared ceramic roughcast, further use of dry powder to fill the pores of the interception layer of the ceramic roughcast, so that without increasing the thickness of the interception layer, greatly reducing the number of pores in the interception layer of the ceramic roughcast with a pore size greater than the preset filter pore size, reducing the number of large-size solid particles passing through the interception layer, and improving the filtering effect.

[0133] Further, by soaking the amphoteric fluorocarbon surfactant solution, a hydrophilic film layer is formed on the outer layer and the internal pore layer of the whisker-reinforced ceramic blank, further enhancing its hydrophilic and oleophobic properties, improving separation efficiency, reducing the situation of oil droplets adhering to the surface, and reducing the plugging rate.

[0134] In addition, since the whisker-reinforced double-layer porous ceramic plate of the present disclosure has an extremely thin interception layer, small pore diameter of the interception layer, and a large-size cavity structure of the support layer, the solid particles clogging the interception layer pores and the oil accumulated in the support layer cavities can be removed by backwashing the whisker-reinforced double-layer porous ceramic plate after a period of use, thereby restoring the filtration flux. Therefore, the whisker-reinforced double-layer porous ceramic plate of the present disclosure can be repeatedly used, reducing the cost of cleaning and replacement.

[0135] In addition, the present disclosure further selects quartz ceramic powder as the base material, thereby obtaining a whisker-reinforced double-layer porous ceramic plate with stable physical properties that can be used for a long time, making the present disclosure suitable for large-scale industrial application.

[0136] Those skilled in the art in this technical field can understand and implement other changes to the disclosed embodiments by reading the specification, the disclosed content, the accompanying drawings, and the appended claims, all of which fall within the scope of protection of the claims of the present disclosure without deviating from the essence of the claims of the present disclosure.

Claims

1. A whisker-reinforced double-layered porous ceramic plate, characterized by, The whisker-reinforced double-layer porous ceramic plate comprises an interception layer and a support layer, the interception layer has through holes, the thickness of the interception layer is 45-120 μm, the support layer has a cavity structure, the through holes of the interception layer are communicated with the cavity structure, the through holes of the interception layer are provided with whiskers with a reticular structure in the cavity structure, and the through air hole rate of the whisker-reinforced double-layer porous ceramic plate is greater than 50%.

2. The whisker-reinforced double-layer porous ceramic plate according to claim 1, characterized by The through air hole rate of the whisker-reinforced double-layer porous ceramic plate is 54%-80%.

3. The whisker-reinforced double-layer porous ceramic plate according to claim 1, characterized by, The proportion of the through holes with a pore size greater than a preset filtration pore size in the through holes with a pore size greater than 5 μm in the interception layer is less than 20%.

4. The whisker-reinforced double-layer porous ceramic plate according to claim 1, characterized by The whisker is a silica whisker, and the diameter of the whisker is 50-150 nm.

5. The whisker-reinforced double-layer porous ceramic plate according to claim 1, characterized by The thickness of the support layer is 8-32 mm.

6. The whisker-reinforced double-layer porous ceramic plate according to claim 1, characterized by The outer surface layer and the internal pore surface layer of the whisker-reinforced double-layer porous ceramic plate are provided with a hydrophilic film layer.

7. The whisker-reinforced double-layer porous ceramic plate according to claim 6, characterized by The hydrophilic film layer is an amphoteric fluorocarbon surfactant.

8. The whisker-reinforced double-layer porous ceramic plate according to claim 1, characterized by The cavity structure of the support layer is formed by using a foaming process.

9. The whisker-reinforced double-layer porous ceramic plate according to claim 1, characterized by The whisker-reinforced double-layer porous ceramic plate is prepared by using a quartz powder.

10. A method of making a whisker-reinforced double-layered porous ceramic plate, characterized by, The method comprises the following steps: S1, a main material comprising a first ceramic powder, a single crystal silicon powder and water is stirred and mixed with a binder and a dispersant to form a first mixed slurry, the silica content of the first ceramic powder is ≥70%; S2, a foaming agent is added to the first mixed slurry and stirred to form a foamed slurry; S3, the foamed slurry is injected into at least one oil paper mold, and a ceramic rough blank is obtained after natural drying, wherein the contact surface of the ceramic rough blank and the oil paper forms an interception layer; S4, a second ceramic powder is used to fill the pores of the interception layer of the ceramic rough blank to form a ceramic blank; S5, the ceramic blank is embedded in carbon and sintered by using a carbon-embedded sintering method, the temperature is raised to 1000-1200 ℃ at a temperature rising rate of 4-10 ℃ / min, and the temperature is kept for more than 1 hour to obtain the whisker-reinforced double-layer porous ceramic plate, wherein the mass percentage of the main material is as follows: the first ceramic powder is 23-60%, the single crystal silicon powder is 10-15%, and the water is 25-67%, and the binder, the dispersant and the foaming agent are all 0.3-2% of the total mass of the main material.

11. The method of claim 10, wherein, After the temperature keeping step in step S5, the method further comprises the following steps: S6, the sintered ceramic blank is soaked in an amphoteric fluorocarbon surfactant solution, and then taken out and dried to obtain the whisker-reinforced double-layer porous ceramic plate, wherein the concentration of the amphoteric fluorocarbon surfactant solution is 5%-8%.

12. The method of claim 10, wherein, The mass percentage of the main material is as follows: the first ceramic powder is 38-50%, the single crystal silicon powder is 10-12%, and the water is 38-52%, and the binder, the dispersant and the foaming agent are respectively 1-2%, 1-2% and 0.3-1% of the total mass of the main material.

13. The method of claim 10, wherein, The mesh number of the first ceramic powder is 200-500 mesh.

14. The method of claim 10, wherein, The silicon content in the single crystal silicon powder is ≥95%, and the mesh number of the single crystal silicon powder is 200-500 mesh.

15. The preparation method according to claim 10, characterized in that, The first ceramic powder is any one or more of quartz, diatomite, and silica, and the second ceramic powder is any one or more of quartz, diatomite, silica, mullite, kaolin, sepiolite, and dolomite.

16. The method of claim 15, wherein, The first ceramic powder and the second ceramic powder are both quartz.

17. The method of claim 10, wherein, The adhesive is any one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, xanthan gum, and gelatin.

18. The method of claim 10, wherein, The foaming agent is any one or more of sodium dodecyl sulfate, sodium dodecyl amino propionate, triethanolamine lauryl sulfate, and carbonates.

19. The method of claim 10, wherein, The dispersing agent is any one or more of polyvinyl alcohol, polyvinyl alcohol copolymer, modified starch, and silicone polyether emulsion.

20. A whisker-reinforced double-layer porous ceramic plate prepared by the method of any one of claims 10 to 19.

21. Use of the whisker-reinforced double-layer porous ceramic plate of any one of claims 1 to 9 or 20 in oil-water separation containing solid particles.

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