Preparation method of high-flux graphene oxide ceramic composite nanofiltration membrane

Abstract

The invention discloses a preparation method of a high-flux graphene oxide ceramic composite nanofiltration membrane, and belongs to the technical field of membrane separation, and the preparation method comprises the following steps: (1) preparing a graphene oxide aqueous solution; (2) soaking the porous ceramic membrane support body with a sodium hydroxide solution to obtain an activated ceramic membrane support body; (3) soaking the activated ceramic membrane support body in a 3-aminopropyldiethoxysilane ethanol solution, and reacting at room temperature to obtain a grafted ceramic membrane support body; (4) at room temperature, diluting a graphene oxide aqueous solution, adding tannic acid and lysine, and carrying out a cross-flow filtration reaction on the surface of the grafted ceramic membrane support; and (5) carrying out heat treatment on the material obtained in the step (4) to obtain the graphene oxide ceramic composite nanofiltration membrane. The prepared high-flux graphene oxide ceramic composite nanofiltration membrane is ordered in structure, high in binding force, high in mechanical strength and suitable for industrial scale production, and has good economical efficiency and application potential.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of membrane separation technology, and particularly relates to a preparation method of a high-flux graphene oxide ceramic composite nanofiltration membrane. BACKGROUND

[0002] Graphene oxide (GO) is a novel two-dimensional nanomaterial with layered structure, abundant oxygen-containing functional groups and high mechanical strength, which has attracted extensive attention in the field of membrane separation. GO membrane is simple to prepare and low in cost, and exhibits great potential in water purification, seawater desalination and molecular separation. Recent studies have shown that the hydrophilicity and water flux of GO membrane can be further improved by regulating sub-nanometer channels and introducing polar functional groups. For example, GO coating has been used in membrane distillation (MD) to improve the flux; GO / ceramic nanofiber composite membrane has high flux and anti-fouling ability in ultrafiltration; and GO layer deposited on the surface of ceramic hollow fiber can also obtain good nanofiltration performance, but the microstructure stability still needs to be improved.

[0003] Currently, the preparation strategies of GO composite membrane mainly include chemical grafting, interlayer crosslinking and nanocomposite. GO / ceramic membrane prepared by chemical grafting has excellent performance in water flux and ion rejection, and better stability. Crosslinking GO with polymer monomers or polymers can prepare nanocomposite membranes for forward osmosis (FO), which can alleviate the contradiction between flux and rejection. Layered GO membrane achieves high water flux and high salt rejection in FO desalination, but it is difficult to balance flux, rejection and long-term stability in large-scale production. GO-doped polysulfone (PSf) hollow fiber membrane has been reported to improve the anti-fouling performance by using the hydrophilicity of GO.

[0004] Another development direction of GO-based membrane is to composite with metal oxides or reduced GO to construct ultra-fine nanofiltration membranes, so as to improve the water flux while maintaining high solute rejection. For example, the introduction of GO into nanofiltration membranes can enhance the resistance to oxidizing agents (such as H2O2) and improve the separation performance; intercalated cellulose nanocrystals (CCNC) can increase the interlayer spacing of GO and improve the membrane flux; the water permeability and Na2SO4 rejection rate of reduced porous GO membrane in desalination can be comparable to that of commercial polyamide membrane; Eosin Y crosslinked GO nanofiltration membrane has also been developed to optimize the performance and characterization.

[0005] Despite the obvious advantages, GO membrane still faces three major bottlenecks:

[0006] 1. Poor stability in water: negatively charged GO nanosheets are quickly separated in water due to electrostatic repulsion, and interlayer peeling occurs within a few hours; in the dry state, the microstructure on the ceramic support is unstable due to shrinkage stress.

[0007] 2. "Flux-rejection" trade-off: nanochannels are easily blocked, and high rejection rate is often accompanied by low flux, and vice versa.

[0008] 3. Insufficient anti-pollution ability: traditional nanofiltration membranes are easily polluted by organic or inorganic substances, and the flux rapidly decays; in biological separation, the applications of decolorization, desalination and concentration are also limited due to poor stability.

[0009] In addition, there are still obstacles in large-scale preparation: although the GO mixed matrix membrane for organic solvent nanofiltration is strong and has high flux, the process is complex; the performance of the thin film composite membrane induced by two-dimensional nanosheets deteriorates after long-term operation; the patent mentions the chemical inertness of the GO / ceramic membrane, but liquid-phase film formation is required and the stability needs to be further optimized.

[0010] In summary, the existing technology has made progress in improving the hydrophilicity and mechanical strength of GO membranes, but the balance of flux, retention rate and anti-pollution performance is still the key to its industrialization. Therefore, the development of GO / ceramic composite nanofiltration membranes with high flux, excellent separation efficiency and excellent stability is of great significance to promote their application in industrial water treatment, seawater desalination and molecular separation. SUMMARY

[0011] The purpose of the present application is to overcome the defects of the prior art and provide a preparation method of high-flux graphene oxide / ceramic composite nanofiltration membrane.

[0012] The technical scheme of the present application is as follows:

[0013] A preparation method of high-flux graphene oxide / ceramic composite nanofiltration membrane, comprising the following steps:

[0014] (1) preparing a graphene oxide aqueous solution with a concentration of 2-4 mg / mL;

[0015] (2) soaking the porous ceramic membrane support in a sodium hydroxide solution to obtain an activated ceramic membrane support;

[0016] (3) soaking the activated ceramic membrane support in a 3-aminopropyl diethoxysilane ethanol solution and reacting at room temperature to obtain a grafted ceramic membrane support;

[0017] (4) diluting the graphene oxide aqueous solution obtained in step (1), adding tannic acid and lysine, and mixing uniformly to obtain a graphene oxide dispersion, wherein the mass ratio of tannic acid, lysine and graphene oxide is 1-4:1:1;

[0018] (5) at room temperature, using the graphene oxide dispersion obtained in step (4) to perform cross-flow filtration reaction on the surface of the grafted ceramic membrane support obtained in step (3) for 4-6 min, the cross-flow pressure is 0.2-0.4 MPa, and the surface cross-flow rate is 0.2-0.4 m / s; after the reaction, the unreacted graphene oxide dispersion is removed by rinsing with RO water;

[0019] (6) subjecting the material obtained in step (5) to heat treatment, thereby obtaining the high-flux graphene oxide ceramic composite nanofiltration membrane.

[0020] In the present application, the high-charge graphene oxide membrane surface repels high-valence covalent ions due to its high interaction energy barrier, while inhibiting the penetration of low-valence counter-ions based on the balance of the overall solution charge. The surface-charged graphene oxide membrane with careful adjustment has a significant ion inhibition capacity, and it has high water permeability.

[0021] The present application uses tannic acid and lysine as cross-linking agents for graphene oxide, increasing the interlayer spacing and hydrophilicity. The graphene oxide dispersion liquid is subjected to cross-flow filtration reaction to enable the graphene oxide layers to be uniformly arranged on the activated and graft-modified ceramic membrane support, forming a graphene oxide membrane layer with a compact structure. Through heat reduction treatment, the tannic acid and lysine inserted between the graphene oxide layers chemically bond with the oxygen-containing functional groups of graphene oxide, and the oxygen-containing functional groups on graphene oxide and the functional groups on the activated and graft-modified ceramic membrane support also chemically bond, forming a stable graphene oxide nanofiltration membrane layer with excellent permeability and separation performance.

[0022] In a preferred embodiment of the present application, step (2) comprises: selecting a porous ceramic membrane support with a pore size of 95-105 nm, a length of 45-55 cm, and then subjecting it to ultrasonic treatment for 4-6 h, immersing it in a 1.8-2.2 mol / L sodium hydroxide solution for 20-25 h, drying it at 95-100℃ for 8-12 h, then rinsing it with ethanol and deionized water several times, and drying it at 95-100℃ for 10-14 h and cooling it in the furnace to obtain the activated ceramic membrane support.

[0023] In a preferred embodiment of the present application, step (3) comprises: immersing the activated ceramic membrane support obtained in step (2) in a 3-aminopropyl diethoxysilane ethanol solution with a concentration of 4-6 mmol / L, reacting it at room temperature for 10-12 h, then rinsing it with ethanol and deionized water several times, drying it at 145-150℃ for 10-14 h and cooling it in the furnace to obtain the grafted ceramic membrane support.

[0024] In a preferred embodiment of the present application, step (4) comprises: diluting the graphene oxide aqueous solution obtained in step (1) to 18-22 mg / L, adding tannic acid and lysine, and mixing them uniformly.

[0025] In a preferred embodiment of the present application, the step (5) comprises: performing a cross-flow filtration reaction on the surface of the grafted ceramic membrane support obtained in step (3) with the graphene oxide dispersion obtained in step (4) at room temperature for 5 min, the cross-flow pressure is 0.3 MPa, and the surface cross-flow rate is 0.3 m / s; and after the reaction, the unreacted graphene oxide dispersion is removed by washing with RO water.

[0026] In a preferred embodiment of the present application, the step (6) comprises: after the material obtained in step (5) is placed in a cool place for air drying, heat treating at 80-120℃ for 2-4h, and then cooling in the furnace, the high-flux graphene oxide ceramic composite nanofiltration membrane is obtained.

[0027] In a preferred embodiment of the present application, the material of the porous ceramic membrane support is alumina, titania or zirconia.

[0028] Further preferably, the material of the porous ceramic membrane support is alumina.

[0029] The present application has the following beneficial effects:

[0030] 1. The present application prepares a high-flux graphene oxide ceramic composite nanofiltration membrane on an inorganic ceramic membrane loaded with a crosslinking agent, which has a high pure water flux and rejection rate for magnesium sulfate solution. Specifically, the pure water flux of the membrane can reach 42-51 L / m 2 ·h, and the rejection rate can reach 93.6%-96%, which is significantly better than the membranes without crosslinking agent or with a single crosslinking agent in the prior art.

[0031] 2. The present application adds tannic acid and lysine as crosslinking agents, which increases the interlayer pore size and hydrophilic properties of graphene oxide, and improves the water permeability and separation efficiency of the membrane. At the same time,

[0032] 3. The heat treatment in the present application enhances the bonding force between the graphene oxide layers and the substrate, improves the stability of the membrane in water medium, and solves the problem of easy delamination and damage of the existing GO membrane.

[0033] 4. The high-flux graphene oxide ceramic composite nanofiltration membrane prepared by the present application has ordered structure, strong bonding force and high mechanical strength, is suitable for industrial scale production, and has good economic efficiency and application potential. DETAILED DESCRIPTION

[0034] The technical solutions of the present application are further described and explained in the following specific embodiments.

[0035] The method for preparing graphene oxide by the improved Hummers method in the following examples and comparative examples specifically comprises:

[0036] (1) Take 1000 mL beaker wash dry, add 3 g flake graphite, under magnetic stirring slowly add 360 mL concentrated sulfuric acid (98% H2SO4) and 40 mL concentrated phosphoric acid (95% H3PO4), then slowly add 18 g potassium permanganate (KMnO4) in batches; beaker is moved to 50 °C oil bath, stirring 12 h. Take out the beaker, naturally cool to room temperature. The reaction solution is slowly poured on 400 mL ice block of dilute hydrogen peroxide (containing 18 ml 30% H2O2), the solution becomes bright yellow;

[0037] (2) The solution obtained in step (1) is subjected to cross-flow filtration using a tubular ceramic membrane with a pore size of 0.05 μm to remove impurities, obtaining a graphene oxide solution after impurity removal; the basic principle is to use the pore size screening effect of the tubular ceramic membrane, that is, the pore size of the tubular ceramic membrane is smaller than the size of the GO sheet, so that the GO sheet cannot flow out of the tubular ceramic membrane, but is circulated back to the feed tank, neither blocking the membrane pores nor ensuring the openness of the membrane pores, and also crushing and peeling off the GO sheets with larger size; the pore size of the tubular ceramic membrane is larger than the size of the impurity ions in the GO solution, so that H + , K + , Mn 2+ , and other acid and metal ions can easily pass through the pore size of the ceramic tubular membrane and be discharged. Such repeated circulation realizes the separation of GO from waste acid, K + , and Mn 2+ metal ions, and the collection of GO solution, completing the washing and impurity removal of GO;

[0038] (3) Dilute or concentrate according to the required concentration to obtain graphene oxide aqueous solution with different concentrations.

[0039] Example 1

[0040] (1) Use the above improved Hummers method to prepare a graphene oxide aqueous solution with a concentration of 3 mg / mL;

[0041] (2) Ultrasonic the 100 nm pore size alumina ceramic membrane tube with a length of about 50 cm for 5 h, then soak it in 2 mol / L sodium hydroxide for 24 h, dry it at 100 °C for 10 h, then rinse it with ethanol and deionized water several times, and put it in an oven to dry at a temperature setting value of 100 °C for 12 h and then cool it down with the furnace, obtaining an activated ceramic membrane support;

[0042] (3) Soak the activated ceramic membrane support obtained in step (2) in a 5 mmol / L 3-aminopropyl diethoxysilane ethanol solution, react at room temperature for 12 h, then rinse it with ethanol and deionized water several times, and put it in an oven to dry at a temperature setting value of 150 °C for 12 h and then cool it down with the furnace, obtaining a grafted ceramic membrane support;

[0043] (4) At room temperature, the grafted ceramic membrane support obtained in step (3) is positioned, the above-mentioned graphene oxide aqueous solution is diluted to 20 mg / L, tannic acid and lysine are added, and mixed uniformly, so that the mass ratio of tannic acid, lysine and graphene oxide therein is 1:1:1; then cross-flow filtration reaction is carried out on the surface of the grafted ceramic membrane support obtained in step (3) using the same, the cross-flow pressure is 0.3 MPa, and the surface cross-flow rate is 0.3 m / s; after the cross-flow filtration reaction, RO water is used for flushing to remove the unreacted graphene oxide aqueous solution;

[0044] (5) The material obtained in step (4) is placed in a cool place for air drying, then placed in an oven at 80°C for heat treatment for 3 h, and then cooled in the oven, to obtain the high-flux graphene oxide ceramic composite nanofiltration membrane.

[0045] Membrane tube performance test: the high-flux graphene oxide ceramic composite nanofiltration membrane prepared in the present comparative example is tested at room temperature and under a pressure of 0.6 MPa, the pure water flux is 42 LHM, and the rejection rate for 0.2 wt% magnesium sulfate solution is 96%.

[0046] Example 2

[0047] (1) The above-mentioned improved Hummers method is used to prepare graphene oxide aqueous solution with a concentration of 3 mg / mL;

[0048] (2) The 100 nm pore size alumina ceramic membrane tube with a length of about 50 cm after cutting is ultrasonically treated for 5 h, then soaked in 2 mol / L sodium hydroxide for 24 h, dried at 100°C for 10 h, then sequentially washed with ethanol and deionized water for several times, placed in an oven for drying at a temperature setting value of 100°C for 12 h, and then cooled in the oven, to obtain the activated ceramic membrane support;

[0049] (3) The activated ceramic membrane support obtained in step (2) is soaked in 3-aminopropyl diethoxysilane ethanol solution with a concentration of 5 mmol / L, reacted at room temperature for 12 h, then washed with ethanol and deionized water for several times, placed in an oven for drying at a temperature setting value of 150°C for 12 h, and then cooled in the oven, to obtain the grafted ceramic membrane support;

[0050] (4) At room temperature, the grafted ceramic membrane support obtained in step (3) is positioned, the above-mentioned graphene oxide aqueous solution is diluted to 20 mg / L, tannic acid and lysine are added, and mixed uniformly, so that the mass ratio of tannic acid, lysine and graphene oxide therein is 2:1:1; then cross-flow filtration reaction is carried out on the surface of the grafted ceramic membrane support obtained in step (3) using the same, the cross-flow pressure is 0.3 MPa, and the surface cross-flow rate is 0.3 m / s; after the cross-flow filtration reaction, RO water is used for flushing to remove the unreacted graphene oxide aqueous solution;

[0051] (5) The material obtained in step (4) is placed in a cool place to dry, then placed in an oven at 80°C for heat treatment for 3h, and then cooled in the oven to obtain a high-flux graphene oxide ceramic composite nanofiltration membrane.

[0052] Membrane tube performance test: The high-flux graphene oxide ceramic composite nanofiltration membrane prepared in this example is tested at room temperature and under a pressure of 0.6 MPa, and has a pure water flux of 46 LHM and a rejection rate of 95.2% for a 0.2 wt% magnesium sulfate solution.

[0053] Example 3

[0054] (1) An aqueous graphene oxide solution with a concentration of 3 mg / mL is prepared using the improved Hummers method described above;

[0055] (2) An alumina ceramic membrane tube with a pore size of 100 nm and a length of about 50 cm after cutting is ultrasonically treated for 5h, then soaked in 2 mol / L sodium hydroxide for 24h, dried at 100°C for 10h, then rinsed with ethanol and deionized water several times, placed in an oven and dried at a temperature setting of 100°C for 12h, and then cooled in the oven to obtain an activated ceramic membrane support;

[0056] (3) The activated ceramic membrane support obtained in step (2) is soaked in a 3- aminopropyl diethoxysilane ethanol solution with a concentration of 5 mmol / L, reacted at room temperature for 12h, then rinsed with ethanol and deionized water several times, placed in an oven and dried at a temperature setting of 150°C for 12h, and then cooled in the oven to obtain a grafted ceramic membrane support;

[0057] (4) At room temperature, the grafted ceramic membrane support obtained in step (3) is positioned, the aqueous graphene oxide solution described above is diluted to 20 mg / L, tannic acid and lysine are added, and mixed uniformly so that the mass ratio of tannic acid, lysine and graphene oxide is 4:1:1; then it is used for cross-flow filtration reaction on the surface of the grafted ceramic membrane support obtained in step (3) for 5 min, the cross-flow pressure is 0.3 MPa, and the surface cross-flow rate is 0.3 m / s; after the cross-flow filtration reaction, it is rinsed with RO water to remove unreacted aqueous graphene oxide solution;

[0058] (5) The material obtained in step (4) is placed in a cool place to dry, then placed in an oven at 80°C for heat treatment for 3h, and then cooled in the oven to obtain a high-flux graphene oxide ceramic composite nanofiltration membrane.

[0059] Membrane tube performance test: The high-flux graphene oxide ceramic composite nanofiltration membrane prepared in this example is tested at room temperature and under a pressure of 0.6 MPa, and has a pure water flux of 46 LHM and a rejection rate of 95.2% for a 0.2 wt% magnesium sulfate solution.

[0060] Comparative Example 1

[0061] (1) An aqueous graphene oxide solution with a concentration of 3 mg / mL was prepared using the improved Hummers method described above;

[0062] (2) An alumina ceramic membrane tube with a pore size of 100 nm and a length of about 50 cm after cutting was ultrasonically treated for 5 h, then soaked in 2 mol / L sodium hydroxide for 24 h, dried at 100°C for 10 h, then washed with ethanol and deionized water several times, and dried in an oven at a temperature setting of 100°C for 12 h and then cooled with the oven to obtain an activated ceramic membrane support;

[0063] (3) The activated ceramic membrane support obtained in step (2) was soaked in a 3- aminopropyl diethoxysilane ethanol solution with a concentration of 5 mmol / L, reacted at room temperature for 12 h, then washed with ethanol and deionized water several times, and dried in an oven at a temperature setting of 150°C for 12 h and then cooled with the oven to obtain a grafted ceramic membrane support;

[0064] (4) The grafted ceramic membrane support obtained in step (3) was positioned, and the aqueous graphene oxide solution described above was diluted to 20 mg / L; then cross-flow filtration was performed on the surface of the grafted ceramic membrane support obtained in step (3) using the solution, with a cross-flow pressure of 0.3 MPa and a surface cross-flow rate of 0.3 m / s; after the cross-flow filtration reaction, the unreacted aqueous graphene oxide solution was removed by washing with RO water;

[0065] (5) The material obtained in step (4) was placed in a cool place to air dry, then placed in an 80°C oven for heat treatment for 3 h, and then cooled with the oven to obtain the comparative membrane.

[0066] Membrane tube performance test: The comparative membrane prepared in this comparative example was tested at room temperature and a pressure of 0.6 MPa, and had a pure water flux of 22 LHM and a rejection rate for a 0.2 wt% magnesium sulfate solution of 92%.

[0067] Comparative Example 2

[0068] (1) An aqueous graphene oxide solution with a concentration of 3 mg / mL was prepared using the improved Hummers method described above;

[0069] (2) An alumina ceramic membrane tube with a pore size of 100 nm and a length of about 50 cm after cutting was ultrasonically treated for 5 h, then soaked in 2 mol / L sodium hydroxide for 24 h, dried at 100°C for 10 h, then washed with ethanol and deionized water several times, and dried in an oven at a temperature setting of 100°C for 12 h and then cooled with the oven to obtain an activated ceramic membrane support;

[0070] (3) The activated ceramic membrane support obtained in step (2) is immersed in a 3- aminopropyl diethoxysilane ethanol solution with a concentration of 5 mmol / L, and reacted at room temperature for 12 h. Then, the obtained product is washed with ethanol and deionized water for several times, and dried in an oven with a temperature setting value of 150 °C for 12 h and then cooled with the oven. Thus, a grafted ceramic membrane support is obtained.

[0071] (4) The grafted ceramic membrane support obtained in step (3) is positioned, and the above graphene oxide aqueous solution is diluted to 20 mg / L. Then, tannic acid is added, and the mixture is uniformly mixed so that the mass ratio of tannic acid to graphene oxide is 1:1. Then, the mixture is used for cross-flow filtration reaction on the surface of the grafted ceramic membrane support obtained in step (3) for 5 min. The cross-flow pressure is 0.3 MPa, and the surface cross-flow rate is 0.3 m / s. After the cross-flow filtration reaction, the unreacted graphene oxide aqueous solution is removed by washing with RO water.

[0072] (5) The material obtained in step (4) is placed in a cool place for air drying, and then placed in an oven at 80 °C for heat treatment for 3 h. After that, the oven is cooled, and thus a comparative membrane is obtained.

[0073] Membrane tube performance test: The comparative membrane prepared in the present comparative example is tested at room temperature and under a pressure of 0.6 MPa. The pure water flux is 35 LHM, and the rejection rate of 0.2 wt% magnesium sulfate solution is 95.3%.

[0074] Comparative Example 3

[0075] (1) The above improved Hummers method is used to prepare a graphene oxide aqueous solution with a concentration of 3 mg / mL;

[0076] (2) An alumina ceramic membrane tube with a pore size of 100 nm and a length of about 50 cm after cutting is ultrasonically treated for 5 h, and then immersed in 2 mol / L sodium hydroxide for 24 h. The obtained product is dried at 100 °C for 10 h, and then washed with ethanol and deionized water for several times. The obtained product is dried in an oven with a temperature setting value of 100 °C for 12 h and then cooled with the oven. Thus, an activated ceramic membrane support is obtained.

[0077] (3) The activated ceramic membrane support obtained in step (2) is immersed in a 3- aminopropyl diethoxysilane ethanol solution with a concentration of 5 mmol / L, and reacted at room temperature for 12 h. Then, the obtained product is washed with ethanol and deionized water for several times, and dried in an oven with a temperature setting value of 150 °C for 12 h and then cooled with the oven. Thus, a grafted ceramic membrane support is obtained.

[0078] (4) At room temperature, the grafted ceramic membrane support obtained in step (3) is positioned, the above-mentioned graphene oxide aqueous solution is diluted to 20 mg / L, lysine is added, and mixed uniformly, so that the mass ratio of lysine and graphene oxide in it is 1:1; then it is used for cross-flow filtration reaction on the surface of the grafted ceramic membrane support obtained in step (3) for 5 min, the cross-flow pressure is 0.3 MPa, and the surface cross-flow rate is 0.3 m / s; after the cross-flow filtration reaction, it is washed with RO water to remove unreacted graphene oxide aqueous solution;

[0079] (5) The material obtained in step (4) is placed in a cool place to dry, then placed in an 80℃ oven for heat treatment for 3h, and then cooled in the oven, to obtain a comparative membrane.

[0080] Membrane tube performance test: the comparative membrane prepared in the present comparative example is tested at room temperature and under a pressure of 0.6 MPa, and the pure water flux is 32 LHM, and the rejection rate of 0.2wt% magnesium sulfate solution is 94.5%.

[0081] The process parameters and technical effects of the above examples and comparative examples are shown in the following table 1:

[0082] Table 1

[0083]

[0084] The above is only a preferred embodiment of the present application, and therefore cannot limit the scope of the present application, that is, equivalent changes and modifications made according to the scope of the present patent and the content of the specification should still be within the scope covered by the present application.

Claims

1. A method for preparing high-flux graphene oxide ceramic composite nanofiltration membranes, characterized by: The method comprises the following steps: (1) preparing a graphene oxide aqueous solution with a concentration of 2-4 mg / mL; (2) soaking the porous ceramic membrane support in a sodium hydroxide solution to obtain an activated ceramic membrane support; (3) soaking the activated ceramic membrane support in a 3-aminopropyl diethoxysilane ethanol solution and reacting at room temperature to obtain a grafted ceramic membrane support; (4) diluting the graphene oxide aqueous solution obtained in step (1), adding tannic acid and lysine, and uniformly mixing to obtain a graphene oxide dispersion, wherein the mass ratio of tannic acid, lysine and graphene oxide is 1-4:1:1; (5) at room temperature, using the graphene oxide dispersion obtained in step (4) to perform cross-flow filtration reaction on the surface of the grafted ceramic membrane support obtained in step (3) for 4-6 min, the cross-flow pressure is 0.2-0.4 MPa, and the surface cross-flow rate is 0.2-0.4 m / s; after the reaction, the unreacted graphene oxide dispersion is removed by washing with RO water; (6) heat treating the material obtained in step (5) to obtain the high-flux graphene oxide ceramic composite nanofiltration membrane.

2. The production method according to claim 1, characterized by: The step (2) comprises: selecting a porous ceramic membrane support with a pore size of 95-105 nm and a length of 45-55 cm, ultrasonic treating for 4-6 h, soaking in a 1.8-2.2 mol / L sodium hydroxide solution for 20-25 h, drying at 95-100 ℃ for 8-12 h, then washing with ethanol and deionized water for several times, drying at 95-100 ℃ for 10-14 h and cooling in the furnace to obtain the activated ceramic membrane support.

3. The production method according to claim 1, wherein: The step (3) comprises: soaking the activated ceramic membrane support obtained in step (2) in a 3-aminopropyl diethoxysilane ethanol solution with a concentration of 4-6 mmol / L and reacting at room temperature for 10-12 h, then washing with ethanol and deionized water for several times, drying at 145-150 ℃ for 10-14 h and cooling in the furnace to obtain the grafted ceramic membrane support.

4. The production method according to claim 1, wherein: The step (4) comprises: diluting the graphene oxide aqueous solution obtained in step (1) to 18-22 mg / L, adding tannic acid and lysine, and uniformly mixing.

5. The production method according to claim 1, wherein: The step (5) comprises: at room temperature, using the graphene oxide dispersion obtained in step (4) to perform cross-flow filtration reaction on the surface of the grafted ceramic membrane support obtained in step (3) for 5 min, the cross-flow pressure is 0.3 MPa, and the surface cross-flow rate is 0.3 m / s; after the reaction, the unreacted graphene oxide dispersion is removed by washing with RO water.

6. The production method according to claim 1, wherein: The step (6) comprises: placing the material obtained in step (5) in a cool place to air dry, then heat treating at 80-120 ℃ for 2-4 h, and then cooling in the furnace to obtain the high-flux graphene oxide ceramic composite nanofiltration membrane.

7. The production method according to any one of claims 1 to 6, characterized by: The material of the porous ceramic membrane support is alumina, titania or zirconia.

8. The production method according to claim 7, characterized by: The material of the porous ceramic membrane support is alumina.

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