CN116283238B - Ceramic membrane for oil-water separation and preparation method thereof - Google Patents

Abstract

The invention discloses a ceramic membrane for oil-water separation and a preparation method thereof, wherein the composition comprises 24%-30% kaolin, 50%-60% alumina, 1% binder and 15%-25% catalyst. Through the catalytic action of ammonium molybdate, an oleophobic layer constructed by mullite whiskers grows on the ceramic surface to form a super-hydrophilic/underwater super-oleophobic oil-water separation ceramic membrane with high oil-water separation efficiency; at the same time, the preparation method of the oil-water separation membrane of the present application is simple, the industrial controllability is strong, no modification is required, and the oil-water separation performance depends on a unique three-layer structure precisely constructed, namely, surface zone I, dense zone II, and loose zone III, the surface zone mainly plays a separation role, the dense zone can stabilize the surface zone, and the loose zone ensures that there is enough flux inside the membrane, so the prepared oil-water separation ceramic membrane has stable performance, light weight and high strength, wear resistance and pressure resistance, and good anti-fouling ability and can be reused.

Description

Ceramic membrane for oil-water separation and preparation method thereof

Technical Field

The invention relates to the technical field of inorganic non-metallic materials, and in particular to an oil-water separation ceramic membrane constructed with mullite whiskers and a preparation method thereof.

Background technique

Oil-water mixtures or emulsions are widely present in the petroleum, chemical, machinery and other industries. They have a great harmful effect on the ecological environment and human health, and affect the production process.

According to the dispersion state of oil-water mixture, it can be simply divided into three categories: free state, dispersed state and emulsified state. Among them, the free state refers to the oil-water mixture in which the water phase and the oil phase are mutually separated, the dispersed state oil-water mixture refers to the oil dispersed in the water phase in the form of droplets, and the emulsified state oil-water mixture includes water-in-oil and oil-in-water emulsions. The diameter of the dispersed phase droplets varies, often between tens of nanometers and tens of microns, and is evenly dispersed in the continuous phase. The oil and hydrocarbons contained in the oil-water mixture will not only evaporate into the atmosphere to cause air pollution, but also penetrate into the soil to pollute groundwater and drinking water.

Chinese patent publication number CN110585930A discloses a method for preparing a ceramic membrane for oil-water separation, wherein a silicon nitride ceramic membrane is used as a matrix, and then activated, dried, and calcined, and then immersed in a mixture of epoxy acrylate, shikonin, 3-allyloxy-1,2-propylene glycol, etc., added to an ethyl acetate solvent and stirred evenly for modification, and the modified ceramic membrane is cured and cross-linked under a UV lamp, and washed and dried to obtain; Chinese patent publication number CN106861435A discloses a method for preparing a polyacrylonitrile biomimetic film for oil-water emulsion separation, wherein a 1 mm thick alumina ceramic diaphragm is used as a support, and a polymer solution prepared from polyacrylonitrile powder is scraped onto the support, and then placed in a non-solvent for a coagulation bath to obtain a super-hydrophilic/underwater super-oleophobic biomimetic polyacrylonitrile film. The above-prepared oil-water separation membrane modification process is cumbersome, the process controllability is not strong, the efficiency is low, the pollution is serious, and it is difficult to recycle.

Chinese patent publication number CN106975369 discloses an aluminum oxide ceramic composite membrane for oil-water separation and a preparation method thereof, wherein aluminum oxide and fly ash are used as main raw materials, acrylamide or isoacrylamide is used as precursor, and a composite ceramic membrane with super hydrophobic/super oleophilic properties is obtained through the steps of solution blending, support sintering, hydrothermal treatment and PDMS surface dip coating; Patent number CN109173346A discloses a preparation method of an oil-water separation membrane with a smooth surface and a method thereof, wherein a polymer membrane composed of a fiber membrane and a porous membrane is roughened and fluorinated to obtain a polymer membrane substrate with a rough structure of silicon dioxide, and then an excess lubricating oil is poured into the rough structure of the polymer surface, and then the excess lubricating oil is removed to obtain an oil-water separation membrane with a smooth surface. The separation membrane has high separation efficiency and separation rate; Chinese patent number CN110526337A discloses a method for preparing an oil-water separation membrane, wherein a SiO2 spherical structure is constructed on a cotton fabric by a sol-gel method, and then polythiophene is coated on the surface by a solid phase coupling method, and then washed and dried to obtain an oil-water separation membrane. The preparation method is simple and easy to operate, and the cotton fabric has oleophobic properties and good separation effect. The above-prepared oil-water separation membrane is suitable for treating oil-in-water emulsions, but not for separating water-in-oil emulsions.

Chinese Patent Publication No. CN109385173 discloses an oleophobic coating material with oil-water separation functional material, its preparation method and use. The oleophobic coating material includes a cross-linked network structure formed by two or more ionic compounds through intermolecular interactions. The oleophobic coating is coated on a substrate, so that the substrate has hydrophilic and oleophobic properties. However, since the oleophobic coating and the substrate are combined by physical bonding force, the oleophobic coating is easily separated from the substrate under the action of water pressure during the oil-water separation process, resulting in a reduction in the oil-water separation effect.

Existing oil-water separation membranes generally have certain shortcomings, such as complex preparation process, weak industrial controllability, high production cost, environmental pollution, and insufficient performance stability.

To this end, we propose a ceramic membrane for oil-water separation and a preparation method thereof.

Summary of the invention

In view of the fact that the above and/or existing oil-water separation membranes generally have certain deficiencies, such as complex preparation process, weak industrial controllability, high production cost, environmental pollution, insufficient performance stability, etc., the present invention is proposed.

Therefore, the purpose of the present invention is to provide a ceramic membrane for oil-water separation and a preparation method thereof, by adopting a super hydrophilic/underwater super oleophobic oil-water separation ceramic membrane constructed by mullite whiskers, the preparation process is simple, the production cost is low, the industrial controllability is strong, it is green and environmentally friendly, no modification is required, and the separation performance depends on the precisely constructed three-layer structure, namely, surface area I, dense area II, and loose area III, with strong performance stability, high separation efficiency, good anti-pollution ability, and reusability.

In order to solve the above technical problems, the present invention provides the following technical solutions:

A ceramic membrane for oil-water separation, comprising the following components:

Kaolin 24%-30%;

Alumina 50%-60%;

Binder 1%;

Catalyst 15%-25%.

As a further improvement of the present solution, the kaolin mainly provides silicon dioxide and aluminum oxide, which are combined with the original aluminum oxide to make the aluminum-silicon molar ratio in the overall raw material 3:2.

As a further improvement of this solution, the catalyst is ammonium molybdate, and the added amount is 20% of the total mass.

A method for preparing a ceramic membrane for oil-water separation comprises the following steps:

1. Preparation of ceramic powder

Step 1, kaolin, alumina, and ammonium molybdate are respectively charged into a ball mill at a ratio of 30%, 50%, and 20% of the total mass;

Step 2, adding deionized water and agate ball milling beads in a mass ratio of powder: water: ball milling beads of 1:1:5 or 1:1:10; ball milling at 100-400r/min for 10-60min using a planetary ball mill;

Step 3, after ball milling, drying in a constant temperature drying oven at 40-120°C for 1-10h, removing the ball milling beads, and grinding the powder through a 50-150 mesh sieve to obtain ceramic powder;

2. Molding Process

Step 4: Take the ceramic powder obtained in the previous step, add a 5%-15% PVA solution as a binder, grind and mix evenly, and then pass through a 20-50 mesh sieve;

Step 5: The sieved powder is loaded into a mold and then pressed into a tablet by a tablet press at 10-20 MPa to obtain a ceramic membrane blank;

3. Sintering

Step 6: Take the ceramic membrane blank from the previous step and perform sintering treatment, heat it to 1000-1400°C at a heating rate of 1-5°C, keep it at the required temperature for 1-5h, then cool it to 300-500°C at a cooling rate of 1-5°C, and cool it in the furnace.

As a further improvement of this solution, in step 1, the ball mill used is a tetrafluoroethylene ball mill.

As a further improvement of this scheme, in step 2, the ratio of powder: water: ball milling beads is 1:1:10, the rotation speed of the planetary ball mill is 380 r/min, and the ball milling time is 30 min.

As a further improvement of this solution, in step 3, the temperature of the constant temperature drying oven is 80° C., and the mixture is dried for 4 hours. The mixture is ground with an agate mortar and passed through a 100-mesh sieve to obtain ceramic powder.

As a further improvement of the present solution, in step 4, the binder is a 10% PVA (polyvinyl alcohol) solution, which is also ground with an agate mortar and then passed through a 35-mesh sieve.

As a further improvement of the present solution, in step 5, the sieved powder is loaded into a mold and then pressed into tablets by a tablet press at a pressure of 16 MPa to obtain a ceramic membrane blank.

As a further improvement of this scheme, in step 6, the ceramic membrane blank is placed in a muffle furnace and heated to 1000-1400°C at 3°C/min. After being kept at the highest temperature for 2 hours, the temperature is lowered to 400°C at 5°C/min and then cooled in the furnace.

Compared with the prior art, this application has the following beneficial effects:

Using kaolin and alumina as raw materials, through the catalytic action of ammonium molybdate, an oleophobic layer built by mullite whiskers grows on the ceramic surface, forming an oil-water separation ceramic membrane with super hydrophilicity/underwater super oleophobicity and high oil-water separation efficiency.

At the same time, the preparation method of the oil-water separation membrane of the present application is simple, the industrial controllability is strong, no modification is required, it is green and environmentally friendly, and the oil-water separation performance depends on the unique three-layer structure constructed with precision, namely the surface zone I, the dense zone II, and the loose zone III. The surface zone mainly plays a separation role, the dense zone can stabilize the surface zone, and the loose zone ensures that there is sufficient flux inside the membrane. Therefore, the prepared oil-water separation ceramic membrane has stable performance, is lightweight and high strength, is wear-resistant and pressure-resistant, has good anti-fouling ability, and can be reused.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a diagram showing an experimental characterization of the underwater oleophobic contact angle of the oil-water separation membrane provided by the present invention;

FIG2 is a physical picture of the oil-water separation ceramic membrane provided by the present invention;

FIG3 is a schematic diagram of an oil-water separation test of an oil-water separation membrane provided by the present invention;

FIG4 is a scanning electron microscope image of the surface of the oil-water separation membrane provided by the present invention magnified 1000 times;

FIG5 is a scanning electron microscope image of the surface of the oil-water separation membrane provided by the present invention magnified 5000 times;

FIG6 is a scanning electron microscope image of the surface of the oil-water separation membrane provided by the present invention magnified 10,000 times;

FIG7 is a scanning electron microscope image of the surface of the oil-water separation membrane provided by the present invention magnified 20,000 times;

FIG8 is a scanning electron microscope image of the internal cross-section of the oil-water separation membrane provided by the present invention, magnified 2000 times;

In Figure 3: a is a water droplet 1 and an oil droplet 2 being added to the oil-water separation membrane at the same time, b is a water droplet 1 passing through the oil-water separation membrane, while the oil droplet 2 does not pass through the oil-water separation membrane, and c is an oil droplet 2 remaining on the surface of the oil-water separation membrane in the form of a water droplet.

In FIG8 , I is the surface area, II is the dense area, and III is the loose area.

Detailed ways

To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

The present invention provides an oil-water separation ceramic membrane constructed with mullite whiskers and a preparation method thereof, which effectively solves the technical defects of the prior art, such as complex process, weak industrial controllability, high production cost, environmental pollution and insufficient performance stability.

Among them, the raw materials used in the following examples are all commercially available or homemade; ceramic powder: kaolin: chemically pure, Sinopharm Chemical Reagent Co., Ltd., α-Al ₂ O ₃ , Tianjin Damao Chemical; ammonium molybdate tetrahydrate: (NH ₄ ) ₆ Mo ₇ O ₂₄ .4H ₂ O, analytically pure, Xilong Scientific Co., Ltd.; polyvinyl alcohol: PVA, alcoholysis degree 98.0-99.0 mol%; viscosity: 3.2-3.8 mPa.s; MW is 44.05; Aladdin Reagent Company.

SEM was performed using a scanning electron microscope SU8010, Hitachi, Japan.

The contact angle was measured using a HARKE-SPCA contact angle tester from Beijing HARKE Experimental Instrument Factory.

The sintering experiments were carried out using a muffle furnace of type M45/14A, produced by Luoyang Sigma Instrument Manufacturing Co., Ltd.

Example 1

The present invention provides a ceramic membrane for oil-water separation, comprising the following components:

Kaolin 25%;

Alumina 50%;

Binder 1%;

Catalyst 24%.

Furthermore, the kaolin mainly provides silicon dioxide and aluminum oxide, which, combined with the original aluminum oxide, makes the aluminum-silicon molar ratio in the overall raw material 3:2.

Furthermore, the catalyst is ammonium molybdate, and the added amount is 20% of the total mass.

Example 2

The present invention provides a ceramic membrane for oil-water separation, comprising the following components:

Kaolin 24%;

Alumina 60%;

Binder 1%;

Catalyst 15%.

Furthermore, the kaolin mainly provides silicon dioxide and aluminum oxide, which, combined with the original aluminum oxide, makes the aluminum-silicon molar ratio in the overall raw material 3:2.

Furthermore, the catalyst is ammonium molybdate, and the added amount is 20% of the total mass.

Example 3

The present invention provides a ceramic membrane for oil-water separation, comprising the following components:

Kaolin 24%;

Alumina 50%;

Binder 1%;

Catalyst 25%.

Furthermore, the kaolin mainly provides silicon dioxide and aluminum oxide, which, combined with the original aluminum oxide, makes the aluminum-silicon molar ratio in the overall raw material 3:2.

Furthermore, the catalyst is ammonium molybdate, and the added amount is 20% of the total mass.

Example 4

The present invention provides a ceramic membrane for oil-water separation, comprising the following components:

Kaolin 30%;

Alumina 50%;

Binder 1%;

Catalyst 19%.

Furthermore, the kaolin mainly provides silicon dioxide and aluminum oxide, which, combined with the original aluminum oxide, makes the aluminum-silicon molar ratio in the overall raw material 3:2.

Furthermore, the catalyst is ammonium molybdate, and the added amount is 20% of the total mass.

Example 5

The present invention provides a ceramic membrane for oil-water separation, comprising the following components:

Kaolin 25%;

Alumina 54%;

Binder 1%;

Catalyst 20%.

Furthermore, the kaolin mainly provides silicon dioxide and aluminum oxide, which, combined with the original aluminum oxide, makes the aluminum-silicon molar ratio in the overall raw material 3:2.

Furthermore, the catalyst is ammonium molybdate, and the added amount is 20% of the total mass.

Example 6

The present application embodiment provides a method for preparing an oil-water separation membrane constructed by mullite whiskers, and the specific preparation steps are as follows:

1. Preparation of ceramic powder

1. Put kaolin, alumina and ammonium molybdate into the ball mill at a ratio of 30%, 50% and 20% of the total mass respectively.

2. Add deionized water and agate ball milling beads in a ratio of 1:1:10 to powder: water: ball milling beads. Use a planetary ball mill at 380r/min for 30 minutes.

3. After ball milling, dry in a constant temperature drying oven at 80°C for 4 hours, remove the ball milling beads, and grind the powder through a 100-mesh sieve to obtain ceramic powder.

2. Molding Process

4. Take the ceramic powder obtained in the previous step, add a 10% PVA solution as a binder, grind and mix evenly, and then pass through a 35-mesh sieve.

5. The sieved powder is loaded into a mold and pressed into a tablet under a pressure of 16 MPa on a tablet press to obtain a ceramic membrane blank.

3. Sintering

6. Take the ceramic membrane blank from the previous step and perform sintering treatment, raise the temperature to 1000°C at 3°C/min, keep it at 1000°C for 2h, then cool it to 400°C at 4°C/min and cool it in the furnace.

Example 7

The present application embodiment provides a method for preparing an oil-water separation membrane constructed by mullite whiskers, and the specific preparation steps are as follows:

1. Preparation of ceramic powder

1. Put kaolin, alumina and ammonium molybdate into the ball mill at a ratio of 30%, 50% and 20% of the total mass respectively.

2. Add deionized water and agate ball milling beads in a ratio of 1:1:10 to powder: water: ball milling beads. Use a planetary ball mill at 380r/min for 30 minutes.

3. After ball milling, dry in a constant temperature drying oven at 80°C for 4 hours, remove the ball milling beads, and grind the powder through a 100-mesh sieve to obtain ceramic powder.

2. Molding Process

4. Take the ceramic powder obtained in the previous step, add a 10% PVA solution as a binder, grind and mix evenly, and then pass through a 35-mesh sieve.

5. The sieved powder is loaded into a mold and pressed into a tablet under a pressure of 16 MPa on a tablet press to obtain a ceramic membrane blank.

3. Sintering

6. Take the ceramic membrane blank from the previous step and perform sintering treatment, raise the temperature to 1100°C at 3°C/min, keep it at 1100°C for 2h, then cool it to 400°C at 4°C/min and cool it in the furnace.

Example 8

The present application embodiment provides a method for preparing an oil-water separation membrane constructed by mullite whiskers, and the specific preparation steps are as follows:

1. Preparation of ceramic powder

1. Put kaolin, alumina and ammonium molybdate into the ball mill at a ratio of 30%, 50% and 20% of the total mass respectively.

2. Add deionized water and agate ball milling beads in a ratio of 1:1:10 to powder: water: ball milling beads. Use a planetary ball mill at 380r/min for 30 minutes.

3. After ball milling, dry in a constant temperature drying oven at 80°C for 4 hours, remove the ball milling beads, and grind the powder through a 100-mesh sieve to obtain ceramic powder.

2. Molding Process

4. Take the ceramic powder obtained in the previous step, add a 10% PVA solution as a binder, grind and mix evenly, and then pass through a 35-mesh sieve.

5. The sieved powder is loaded into a mold and pressed into a tablet under a pressure of 16 MPa on a tablet press to obtain a ceramic membrane blank.

3. Sintering

6. Take the ceramic membrane blank from the previous step and perform sintering treatment, raise the temperature to 1200°C at 3°C/min, keep it at 1200°C for 2h, then cool it to 400°C at 4°C/min and cool it in the furnace.

Example 9

The present application embodiment provides a method for preparing an oil-water separation membrane constructed by mullite whiskers, and the specific preparation steps are as follows:

1. Preparation of ceramic powder

1. Put kaolin, alumina and ammonium molybdate into the ball mill at a ratio of 30%, 50% and 20% of the total mass respectively.

2. Add deionized water and agate ball milling beads in a ratio of 1:1:10 to powder: water: ball milling beads. Use a planetary ball mill at 380r/min for 30 minutes.

3. After ball milling, dry in a constant temperature drying oven at 80°C for 4 hours, remove the ball milling beads, and grind the powder through a 100-mesh sieve to obtain ceramic powder.

2. Molding Process

4. Take the ceramic powder obtained in the previous step, add a 10% PVA solution as a binder, grind and mix evenly, and then pass through a 35-mesh sieve.

5. The sieved powder is loaded into a mold and pressed into a tablet under a pressure of 16 MPa on a tablet press to obtain a ceramic membrane blank.

3. Sintering

6. Take the ceramic membrane blank from the previous step and perform sintering treatment, raise the temperature to 1300°C at 3°C/min, keep it at 1300°C for 2h, then cool it to 400°C at 4°C/min and cool it in the furnace.

Example 10

Referring to FIG. 1 to FIG. 8 , the present application embodiment provides a method for preparing an oil-water separation membrane constructed by mullite whiskers, and the specific preparation steps are as follows:

1. Preparation of ceramic powder

1. Put kaolin, alumina and ammonium molybdate into the ball mill at a ratio of 30%, 50% and 20% of the total mass respectively.

2. Add deionized water and agate ball milling beads in a ratio of 1:1:10 to powder: water: ball milling beads. Use a planetary ball mill at 380r/min for 30 minutes.

3. After ball milling, dry in a constant temperature drying oven at 80°C for 4 hours, remove the ball milling beads, and grind the powder through a 100-mesh sieve to obtain ceramic powder.

2. Molding Process

4. Take the ceramic powder obtained in the previous step, add a 10% PVA solution as a binder, grind and mix evenly, and then pass through a 35-mesh sieve.

5. The sieved powder is loaded into a mold and pressed into a tablet under a pressure of 16 MPa on a tablet press to obtain a ceramic membrane blank.

3. Sintering

6. Take the ceramic membrane blank from the previous step and perform sintering treatment, raise the temperature to 1400°C at 3°C/min, keep it at 1400°C for 2h, then cool it to 400°C at 4°C/min and cool it in the furnace.

The oil cutoff rate, membrane flux, contact angle and compressive strength of the five oil-water separation membranes were measured. The results are shown in Table 1.

See Figures 1 to 8 for oil-water separation performance test:

Add 1g of vacuum pump oil to 1000mL of deionized water and stir evenly to form an oil-in-water emulsion system (the oil concentration is 1g/L). The cross-flow oil-water separation experimental device was used to measure the oil-water separation performance of the water-in-oil emulsion system. The ceramic membrane was sealed on a stainless steel plate with silica gel. The oil-water mixture circulated on one side of the feed tank and the membrane assembly under the action of a centrifugal pump. When the membrane assembly was driven by a pressure of 0.1Mpa, water could pass through the ceramic membrane while the oil droplets were blocked by the ceramic membrane. The membrane flux was calculated by the mass of water permeating per unit time, and the oil retention effect was determined by testing the absorbance of the permeated liquid. The membrane flux and oil retention rate were calculated by the following formula: J=V/(T×A);

Where J is the membrane flux (L/m ² h), V is the sampling volume (L), T is the sampling time (h), and A is the effective membrane area of the ceramic membrane.

R = (C0-C1)/C0×100%;

Where R is the oil retention rate, C0 is the oil concentration of the water-in-oil emulsion, and C1 is the oil concentration of the permeate after membrane filtration.

Table 1 Oil-water separation performance test performance comparison

As shown in Table 1, with the increase of sintering temperature, the oil cutoff rate, membrane flux, contact angle and compressive strength are all improved. The best comprehensive effect is shown in Example 10 (sintering temperature of 1400°C), with an oil cutoff rate of 95%, a membrane flux of 273.7L/ ^m2h , a contact angle of 158.67° and a compressive strength of 42.7Mpa.

The oil-water separation membrane of Example 10 of the present application was subjected to scanning electron microscopy detection, and the results are shown in Figures 4 to 7. Figure 4 is a scanning electron microscopy image of the oil-water separation membrane of Example 10 of the present application magnified 1000 times, Figure 5 is a scanning electron microscopy image of the oil-water separation membrane of Example 5 of the present application magnified 5000 times, Figure 6 is a scanning electron microscopy image of the oil-water separation membrane of Example 10 of the present application magnified 10000 times, and Figure 7 is a scanning electron microscopy image of the oil-water separation membrane of Example 5 of the present application magnified 20000 times. It can be seen from Figures 4 to 7 that the oil-water separation membrane of Example 10 of the present application As shown in Figure 8, the cross-section of the oil-water separation ceramic membrane is viewed under a 2000x scanning electron microscope. The interior of the oil-water separation ceramic membrane constructed by the mullite whiskers of the present application has a precisely constructed three-layer structure, namely, surface zone I, dense zone II, and loose zone III. The surface zone mainly plays a separation role, the dense zone can stabilize the surface zone, and the loose zone ensures that there is sufficient flux inside the membrane. Therefore, the macroscopic level has a higher membrane flux and high-strength compressive resistance, and it is a porous structure, so it has light weight and high strength performance.

Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims (7)

1. The preparation method for the oil-water separation ceramic membrane is characterized by comprising the following steps of:

1. Preparation of ceramic powder

Step 1, respectively loading kaolin, alumina and ammonium molybdate into a ball milling tank according to the proportion of 30%, 50% and 20% of the total mass;

step 2, adding deionized water and agate ball-milling beads according to the mass ratio of the powder to the water to the ball-milling beads of 1:1:5 or 1:1:10; ball milling for 10-60min at 100-400r/min by using a planetary ball mill;

Step 3, drying in a constant temperature drying oven at 40-120 ℃ for 1-10 hours after ball milling, removing ball milling beads, and grinding the powder and sieving with a 50-150 mesh sieve to obtain ceramic powder;

2. Shaping treatment

Step 4, taking the ceramic powder obtained in the previous step, adding a PVA solution with the concentration of 5% -15% as a binder, grinding and uniformly mixing, and sieving with a 20-50 mesh sieve;

step 5, loading the sieved powder into a die, and tabletting and forming under 10-20Mpa by a tabletting machine to obtain a ceramic membrane biscuit;

3. Sintering

Step 6, sintering the ceramic membrane biscuit obtained in the previous step, heating to 1000-1400 ℃ at a heating rate of 1-5 ℃, preserving heat for 1-5h at a required temperature, cooling to 300-500 ℃ at a cooling rate of 1-5 ℃ and cooling with a furnace to obtain the ceramic membrane biscuit;

The inside of the oil-water separation ceramic membrane built by the mullite whiskers is provided with a three-layer structure which is accurately built, and the three-layer structure is a surface area I, a compact area II and a loose area III respectively, wherein the surface area mainly plays a role in separation, the compact area can stabilize the surface area, and the loose area ensures that the inside of the membrane has enough flux.

2. The method for preparing the oil-water separation ceramic membrane according to claim 1, wherein,

In the step 5, the sieved powder is put into a die and then is pressed into tablets under the pressure of 16Mpa by a tablet press to obtain a ceramic membrane biscuit;

in the step 6, the ceramic membrane biscuit is put into a muffle furnace, heated to 1000-1400 ℃ at 3 ℃/min, kept at the highest temperature for 2 hours, cooled to 400 ℃ at 5 ℃/min and then cooled along with the furnace.

3. The method for preparing an oil-water separation ceramic membrane according to claim 1, wherein in the step 1, the ball milling tank is a tetrafluoroethylene ball milling tank.

4. The method for preparing the oil-water separation ceramic membrane according to claim 1, wherein in the step 2, the ratio of powder to water to ball-milling beads is 1:1:10, the rotating speed of a planetary ball mill is 380r/min, and the ball-milling time is 30min.

5. The method for preparing an oil-water separation ceramic membrane according to claim 1, wherein in the step 3, the temperature of a constant temperature drying oven is 80 ℃, the drying is carried out for 4 hours, and the ceramic powder is obtained by grinding the ceramic membrane with an agate mortar and sieving the ceramic powder with a 100-mesh sieve.

6. The method for preparing an oil-water separation ceramic membrane according to claim 1, wherein in the step 4, the binder is a 10% PVA (polyvinyl alcohol) solution, and is also ground with an agate mortar and then screened through a 35 mesh screen.

7. The method for producing an oil-water separation ceramic membrane according to claim 1, wherein the oil-water separation ceramic membrane is produced according to the method for producing an oil-water separation ceramic membrane.