A method for preparing a surface-coated cellulose composite film, the composite film prepared thereby, and applications thereof

Abstract

The application provides a preparation method of a surface-coated cellulose composite membrane, the prepared composite membrane and application, comprising the following steps: stirring MOF@ZnO in N-N dimethylacetamide, adding polyvinylpyrrolidone and continuing to stir, and ultrasonic treatment to obtain a mixed solution; immersing the casting solution on a carrier, and placing the immersed carrier in a glass sheet and deionized water to obtain an ultrafiltration membrane; and soaking the obtained ultrafiltration membrane in a cellulose solution with Tris-HCl buffer solution to obtain a MOF@ZnO@Cellulose@PVDF composite separation membrane. The separation membrane has excellent separation efficiency and flux recovery rate for five different oil-water mixtures of kerosene, gasoline, 1,2 dichloroethane, edible oil and n-hexane. The preparation process of the oil-water separation membrane is simple, the cost is low, the reaction condition is mild, and when the oil-water separation membrane is applied to organic wastewater separation, the oil-water separation membrane has the advantages of high efficiency, good removal performance and good recycling performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of membrane preparation, and particularly relates to a preparation method of a composite membrane coated with cellulose on the surface, the composite membrane prepared by the method and application thereof. BACKGROUND

[0002] With the acceleration of industrialization process worldwide, various industrial production will produce a large amount of oil-containing wastewater, which poses a serious threat to the ecological environment and a major challenge to human health. Especially in the oil-containing wastewater, water-soluble pollutants such as dyes and heavy metal ions have a greater and greater threat to water resources, pollution sources and ecological environment. Conventional separation technologies such as air flotation, chemical coagulation and adsorption have been widely used. They are suitable for purifying oil-containing wastewater. However, they all have their own defects, such as low efficiency and high cost. The application of these methods in oil-water separation is discussed. In addition, this method can be used to separate emulsions with stability and can be used in emulsifiers. After using chemical agents, the emulsification effect is poor, resulting in large energy consumption and secondary pollution.

[0003] In recent years, there has been a rapid increase in demand for materials that can effectively and quickly separate oil-water mixtures and oil-water emulsions.

[0004] However, the currently prepared membranes have low separation efficiency, poor anti-pollution ability, large viscosity, and the like.

[0005] Therefore, it is still an urgent problem to be solved to develop an oil-water separation membrane with good separation efficiency, good stability and good reusability. SUMMARY

[0006] This section aims to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0007] In view of the above and / or problems existing in the prior art, the present application is proposed.

[0008] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art and provide a preparation method of a composite membrane coated with cellulose on the surface.

[0009] To solve the above technical problems, the present application provides the following technical scheme: a preparation method of a composite membrane coated with cellulose on the surface, comprising,

[0010] Mixing DMF, ZrCl4 and H2ATA, ultrasonic treatment, adding acetic acid, pouring the prepared solution into an autoclave for high temperature reaction;

[0011] After the reaction is completed, the solution is centrifuged to obtain a yellow crystalline solid, which is washed with DMF and ethanol, and the obtained yellow crystalline solid is high-temperature baked;

[0012] The yellow crystalline solid is dispersed in an ethanol solution with ZnO nanoparticles, ultrasonic mixing is performed, and the MOF@ZnO material is prepared by drying and grinding;

[0013] The MOF@ZnO is dispersed in N-N dimethylacetamide and stirred, polyvinylpyrrolidone is added and continues to be stirred, and a mixed solution is obtained by ultrasonic treatment;

[0014] Polyvinylidene fluoride powder is added to the mixed solution and stirred to mix uniformly, and the casting solution is prepared by standing and defoaming;

[0015] The casting solution is immersed on a carrier, and the immersed carrier is placed in a glass sheet and deionized water to obtain an ultrafiltration membrane;

[0016] The obtained ultrafiltration membrane is immersed in a cellulose solution with Tris-HCl buffer solution to obtain a MOF@ZnO@Cellulose@PVDF composite separation membrane.

[0017] As a preferred scheme of the preparation method, the material ratio of DMF, ZrCl4 and H2ATA is 50 mL:(0.5-2 mmol):(0.5-2 mmol).

[0018] As a preferred scheme of the preparation method, the ratio of acetic acid to DMF is 5-7 mL:50 mL.

[0019] As a preferred scheme of the preparation method, the prepared solution is poured into an autoclave for high temperature reaction, wherein the reaction temperature is 120-125°C, and the reaction time is 12-24h.

[0020] As a preferred scheme of the preparation method, the obtained yellow crystalline solid is high-temperature baked, wherein the treatment temperature is 80°C, and the time is 10-12h.

[0021] As a preferred scheme of the preparation method, the yellow crystalline solid is dispersed in an ethanol solution with ZnO nanoparticles, wherein the material ratio of MOF material to ZnO is (0.1-0.9):(0.1-0.9).

[0022] As a preferred scheme of the preparation method, the mixing solution, wherein the ratio of MOF@ZnO, N-N dimethylacetamide, polyvinylpyrrolidone is 0.1g:40ml:0.1g, and the particle size of MOF@ZnO is 1300 mesh.

[0023] As a preferred scheme of the preparation method, the mixing solution, wherein the ratio of MOF@ZnO, N-N dimethylacetamide, polyvinylpyrrolidone is 0.1g:40ml:0.1g, and the particle size of MOF@ZnO is 1300 mesh.

[0024] As a preferred scheme of the preparation method, the mixing solution, wherein the ratio of MOF@ZnO, N-N dimethylacetamide, polyvinylpyrrolidone is 0.1g:40ml:0.1g, and the particle size of MOF@ZnO is 1300 mesh.

[0025] Another object of the present application is to provide a MOF@ZnO@Cellulose@PVDF composite membrane prepared by the preparation method.

[0026] Another object of the present application is to provide a MOF@ZnO@Cellulose@PVDF composite membrane prepared by the preparation method.

[0027] The present application has the following beneficial effects:

[0028] (1) The MOF@ZnO@Cellulose@PVDF composite membrane prepared by the method has the characteristics of strong anti-pollution performance, obvious oil-water separation effect, simple preparation process, and low preparation cost, and has good commercial prospects in the field of membrane technology. The ultrafiltration membrane prepared by the present application can achieve nearly 100% rejection effect, and the filtration flux is about 5 times that of the original PVDF membrane, showing excellent oil-water separation effect.

[0029] (2) The ultrafiltration membrane prepared by the method has excellent anti-pollution ability. The results of the anti-pollution test show that the ultrafiltration membrane prepared by the method has a flux recovery rate of nearly 100% after filtering the oil-water emulsion (the unmodified ultrafiltration membrane has a flux recovery rate of only 70%), and the flux decay rate of the modified membrane is much lower than that of the unmodified membrane, indicating that the ultrafiltration membrane of the present application not only has high oil-water separation efficiency, but also can achieve high recovery rate after oil-water separation, maintain the effectiveness of its own flux, and effectively prevent pollution. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without paying the creative labor. Among them:

[0031] Figure 1 SEM diagram of the composite membrane prepared in the embodiment of the present application.

[0032] Figure 2 The filtering effect diagram of the composite membrane prepared in the embodiment of the present application on different kinds of oil. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application will be described in detail below.

[0034] In the following description, a lot of specific details are set forth in order to give a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0035] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an independent or alternative embodiment.

[0036] In the present application, ZnO nanoparticles are purchased from Hangzhou Metal Material, with a particle size of 20 nm; dimethylacetamide is purchased from the National Pharmaceutical Group; polyvinylpyrrolidone (PVP-K30) is purchased from the National Pharmaceutical Group; ZrCl4 is purchased from Macklin, 2-amino terephthalic acid is purchased from Macklin, and cellulose is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0037] In the present application, the oil-water mixture separation performance test of the composite separation membrane is carried out:

[0038] (1) Water flux test method: the time of 100ml pure water through the composite membrane by using vacuum filtration device is used to determine the water flux of the membrane, and the specific formula is:

[0039] In the formula, V (L), A (m 2 ), Δt (h) are the filtrate volume, effective membrane permeation area and filtration time respectively.

[0040] (2) Oil flux test method: The water flux of the membrane was determined by the time taken to filter 100 ml of oil-in-water emulsion (kerosene emulsion, prepared by adding 990 mL of deionized water to a container, taking 30 mg of SDS as an emulsifier, then adding 10 mL of kerosene to the above solution, ultrasonic stirring for 30 min, and then strong stirring for 6 h to obtain a surfactant-stabilized emulsion) through the composite membrane using a vacuum filtration device. The specific formula is

[0041] In the formula, V (L), A (m2), Δt (h), and ΔP (bar) are the filtrate volume, effective membrane permeation area, filtration time, and transmembrane pressure, respectively.

[0042] (3) Retention rate test method: After 100 ml of oil-in-water emulsion (kerosene emulsion, prepared as above) was filtered through the composite membrane using a vacuum filtration device, the concentrations of the solutions before and after filtration were measured using an infrared oil meter. The specific formula is

[0043] Where C i (mg / L) and C0(mg / L) are the oil contents in the filtrate and the original feed emulsion, respectively.

[0044] (4) Flux recovery rate test method: The water flux of the membrane after filtering 100 ml of kerosene using a vacuum filtration device was measured again after simple cleaning. The formula is

[0045] Where J W1 and J W2 are the pure water fluxes before and after filtering the emulsion, respectively.

[0046] Example 1

[0047] (1) A clean beaker was taken, 50 ml of DMF, 1 mmol of ZrCl4 and 1 mmol of H2ATA were added, and 7 ml of acetic acid solution was added while ultrasonic stirring for 15 min.

[0048] (2) The prepared solution was poured into a 100 mL autoclave and reacted at 125°C for 24 hours. After the reaction was completed, the solution was centrifuged to obtain the desired yellow crystalline solid, which was then washed several times with DMF and ethanol, and then the crystals were baked at 80°C for 12 hours.

[0049] (3) The obtained yellow crystals were added to 50 ml of ethanol solution with 100 mg of ZnO nanoparticles, and then treated with 60W ultrasonic stirring for 70 min. The mixed solution after ultrasonic stirring was baked at 80°C for 12 h to obtain the composite material, and then ground to 1300 mesh by a mortar to reduce the agglomeration phenomenon, and then the MOF@ZnO material was collected.

[0050] (4) 0.1 g MOF@ZnO was dispersed in 40 ml of N-N dimethylacetamide at room temperature with magnetic stirring for 20 minutes, then 0.1 g of polyvinylpyrrolidone (molecular weight 111.1418) was added and magnetic stirring was continued at room temperature for 20 minutes, then ultrasonic treatment was carried out for 10 minutes to obtain a mixed solution.

[0051] (5) 3 g of polyvinylidene fluoride powder was added to the mixed solution, then magnetic stirring was carried out at 70°C for 5 h, and after the mixed casting solution was uniformly mixed, it was left to stand for 12 h to remove bubbles.

[0052] (6) The casting solution was slowly moved on a glass plate with a 100 um spatula, then placed in deionized water to form a film, and after soaking for 10 minutes, it was taken out and washed to obtain an ultrafiltration membrane (thickness 100 um).

[0053] (7) The obtained ultrafiltration membrane was placed in a 100 mg / L cellulose solution with Tris-HCl buffer solution at room temperature for 2 h.

[0054] (8) The ultrafiltration membrane was repeatedly washed several times with deionized water to wash away the residual organic solvent, and the SEM image of the composite membrane is shown in Figure 1 .

[0055] Example 2

[0056] (1) A clean beaker was taken, 60 ml of DMF, 1.5 mmol of ZrCl4 and 1.5 mmol of H2ATA were added, and 7 ml of acetic acid solution was added while ultrasonic treatment was carried out for 15 min.

[0057] (2) The prepared solution was poured into a 100 mL autoclave and reacted at 135°C for 24 hours. After the reaction was completed, the solution was centrifuged to obtain the desired yellow crystalline solid, which was then washed several times with DMF and ethanol, and then the crystals were baked at 90°C for 12 hours.

[0058] (3) The obtained yellow crystals were added to 50 ml of ethanol solution with 120 mg of ZnO nanoparticles, and then ultrasonic treatment was carried out for 80 min at 60W, and the mixed solution after ultrasonic treatment was baked at 90°C for 12 h to obtain a composite material, and then it was ground to 1300 mesh in a mortar to reduce its agglomeration phenomenon, and then the MOF@ZnO material was collected.

[0059] (4) 0.1 g MOF@ZnO was dispersed in 40 ml of N-N dimethylacetamide at room temperature with magnetic stirring for 20 minutes, then 0.1 g of polyvinylpyrrolidone (molecular weight 111.1418) was added and magnetic stirring was continued at room temperature for 20 minutes, then ultrasonic treatment was carried out for 10 minutes to obtain a mixed solution.

[0060] (5) 3g of polyvinylidene fluoride powder was added to the mixture and then magnetically stirred at 50°C for 7h, mixed into a uniform casting solution and left to stand for 14h to remove bubbles.

[0061] (6) The casting solution was slowly moved on a glass plate using a 150um spatula and then placed in deionized water to form a film, which was removed after 15 minutes of soaking and washed to obtain an ultrafiltration membrane (thickness 150um).

[0062] (7) The obtained ultrafiltration membrane was placed in a 120mg / L cellulose solution with Tris-HCl buffer solution at room temperature for 2h

[0063] (8) The ultrafiltration membrane was repeatedly washed several times with deionized water to remove residual organic solvents.

[0064] Example 3

[0065] (1) A clean beaker was taken, 65ml of DMF, 2mmol of ZrCl4 and 2mmol of H2ATA were added, and 7ml of acetic acid solution was added while ultrasonicating for 15min.

[0066] (2) The prepared solution was poured into a 100mL autoclave and reacted at 140°C for 24h. After the reaction was completed, the solution was centrifuged to obtain the desired yellow crystalline solid, which was then washed several times with DMF and ethanol, and then the crystals were baked at 100°C for 12h.

[0067] (3) The obtained yellow crystals were added to 60ml of ethanol solution with 150mg of ZnO nanoparticles, and then ultrasonicated for 90min, and the mixed solution after ultrasonication was baked at 90°C for 12h to obtain a composite material, which was then ground to 1300 mesh in a mortar to reduce its agglomeration, and then the MOF@ZnO material was collected.

[0068] (4) 0.1g of MOF@ZnO was dispersed in 40ml of N-N dimethylacetamide and magnetically stirred at room temperature for 20min, then 0.1g of polyvinylpyrrolidone (molecular weight 111.1418) was added and magnetically stirred at room temperature for another 20min, and then ultrasonicated for 10min to obtain a mixed solution.

[0069] (5) 3g of polyvinylidene fluoride powder was added to the mixture and then magnetically stirred at 60°C for 8h, mixed into a uniform casting solution and left to stand for 16h to remove bubbles.

[0070] (6) The casting solution was slowly moved on a glass plate using a 150um spatula and then placed in deionized water to form a film, which was removed after 20 minutes of soaking and washed to obtain an ultrafiltration membrane.

[0071] (7) The obtained ultrafiltration membrane was immersed in a 150 mg / L cellulose solution with Tris-HCl buffer solution at room temperature for 2 h.

[0072] (8) The ultrafiltration membrane was repeatedly washed several times with deionized water to wash away the residual organic solvent.

[0073] The MOF@ZnO@Cellulose@PVDF composite separation membrane prepared in Example 1 was taken for oil-water mixture separation performance test, and edible oil, n-hexane, kerosene, petroleum ether were used as oil-in-water emulsion (990 mL of deionized water was added to the container, 30 mg of SDS was taken as an emulsifier; then, 10 mL of the corresponding oil was added to the above solution, ultrasonic stirring was carried out for 30 min, and then strong stirring was carried out for 6 h to obtain a surfactant-stabilized emulsion), as Figure 2 It can be concluded that the MOF@ZnO@Cellulose@PVDF composite separation membrane has good separation efficiency.

[0074] The MOF@ZnO@Cellulose@PVDF composite separation membrane prepared in Example was taken, and its water flux, oil filtration effect and flux recovery rate were tested as shown in Table 1.

[0075] Table 1

[0076] Water flux (L / m 2 ·h) Oil flux (L / m 2 • h) Retention (%) Flux recovery (%) Example 1 2980 700.2 99.2 98.6 Example 2 2750 680.7 98.6 97.9 Example 3 2800 676.2 98.8 98.4

[0077] Comparative Example 1

[0078] (1) A clean beaker was taken, 65 ml of DMF, 2 mmol of ZrCl4 and 2 mmol of H2ATA were added, and 7 ml of acetic acid solution was added while ultrasonic stirring for 15 min.

[0079] (2) The prepared solution was poured into a 100 mL autoclave, and reacted at 140°C for 24 hours. After the reaction was completed, the solution was centrifuged to obtain the desired yellow crystalline solid, which was then washed with DMF and ethanol several times, and then the crystals were baked at 100°C for 12 hours.

[0080] (3) The obtained yellow crystals were added to 60 ml of ethanol solution, and then treated by ultrasonic stirring for 90 min, and then baked at 90°C for 12 h to obtain a composite material, and then ground to 1300 mesh by a mortar to reduce its agglomeration phenomenon, and then the MOF material was collected.

[0081] (4) 0.1 g of MOF was dispersed in 40 ml of N-N dimethylacetamide and magnetically stirred at room temperature for 20 minutes, then 0.1 g of polyvinylpyrrolidone (molecular weight 111.1418) was added and magnetically stirred at room temperature for another 20 minutes, and then ultrasonic treatment was carried out for 10 minutes to obtain a mixed solution.

[0082] (5) 3 g of polyvinylidene fluoride powder was added to the mixture and then stirred magnetically at 60°C for 8 h, and after the casting solution was mixed uniformly, it was left to stand for 16 h to remove bubbles.

[0083] (6) The casting solution was slowly moved on a glass plate using a 150-μm doctor blade and then immersed in deionized water to form a membrane, and after being immersed for 20 min, it was taken out and washed to obtain an ultrafiltration membrane.

[0084] (7) The obtained ultrafiltration membrane was immersed in a 150 mg / L cellulose solution in a Tris-HCl buffer solution at room temperature for 2 h

[0085] (8) The ultrafiltration membrane was repeatedly washed several times with deionized water to remove residual organic solvents.

[0086] Comparative Example 2

[0087] (1) 0.1 g of ZnO was dispersed in 40 ml of N-N dimethylacetamide at room temperature and stirred magnetically for 20 min, and then 0.1 g of polyvinylpyrrolidone (molecular weight 111.1418) was added and stirred magnetically at room temperature for 20 min, and then ultrasonically treated for 10 min to obtain a mixed solution.

[0088] (2) 3 g of polyvinylidene fluoride powder was added to the mixture and then stirred magnetically at 60°C for 8 h, and after the casting solution was mixed uniformly, it was left to stand for 16 h to remove bubbles.

[0089] (3) The casting solution was slowly moved on a glass plate using a 150-μm doctor blade and then immersed in deionized water to form a membrane, and after being immersed for 20 min, it was taken out and washed to obtain an ultrafiltration membrane.

[0090] (4) The obtained ultrafiltration membrane was immersed in a 150 mg / L cellulose solution in a Tris-HCl buffer solution at room temperature for 2 h

[0091] (8) The ultrafiltration membrane was repeatedly washed several times with deionized water to remove residual organic solvents.

[0092] Comparative Example 3

[0093] On the basis of Example 3, no cellulose was added, and the other conditions were the same as in Example 3.

[0094] The water flux, oil filtration effect, and flux recovery rate were tested as shown in Table 2.

[0095] Table 2

[0096]

[0097] As can be seen from Table 2, the MOF@ZnO@Cellulose@PVDF composite separation membrane prepared from Example 3 is subjected to oil-water mixture separation performance test with Comparative Examples 1, 2 and 3, kerosene is used as oil-in-water emulsion, as shown in Table 2, it can be concluded that the MOF@ZnO@Cellulose@PVDF can greatly improve the oil-water separation performance of the composite membrane and the stability of the membrane due to the unique octahedral structure of the MOF material which can load nanoparticles on the framework, and the composite particles can be more firmly embedded in the membrane due to the addition of the hydrophilic organic coating, and the hydrophilicity of the hydrophilic organic coating membrane is greatly increased, which provides an effective basis for practical application.

[0098] The integration of MOF and ZnO not only solves the problems of few types of active sites of MOF and limited types of catalytic reactions, but also solves the defect of easy aggregation of ZnO in the reaction process, effectively cooperates the respective advantages of ZnO and MOF, and widens the application reaction range and prospect. Therefore, the ZnO / MOF composite material has very broad prospects.

[0099] Comparative Example 4

[0100] On the basis of Example 1, the cellulose concentration is added to 50 mg / L, and the other conditions are the same as those in Example 1.

[0101] Comparative Example 5

[0102] On the basis of Example 1, the cellulose concentration is added to 150 mg / L, and the other conditions are the same as those in Example 1.

[0103] Comparative Example 6

[0104] On the basis of Example 1, the cellulose concentration is added to 200 mg / L, and the other conditions are the same as those in Example 1. The performance determination results are shown in Table 3.

[0105] Table 3

[0106]

[0107] It can be seen that when the cellulose content is less than 100 mg / L, the hydrogel solution formed thereby cannot form a hydration layer on the surface of the membrane, and cannot increase the hydrophilicity and separation efficiency of the membrane; when it is higher than 100 mg / L, the coating formed on the surface of the cellulose solution cannot form a synergistic reaction with the composite particles, resulting in poor comprehensive performance.

[0108] The preparation method of the hydrophilic oil-water separation membrane provided by the application mainly has the following principle: in the pore forming mode, a pore forming agent polyvinylpyrrolidone is used to form pores, and particles are embedded in the pore positions of the membrane. Moreover, the MOF material has a unique octahedral structure, which can better load ZnO nanoparticles on the MOF metal framework, and the addition of a hydrophilic organic coating can more firmly embed the composite particles in the membrane and prevent the loss of the composite particles due to the number of filtration, so that the prepared membrane can achieve good effects in oil-water separation.

[0109] The technical problem to be solved by the application is to provide a preparation method of a MOF@ZnO@Cellulose@PVDF composite membrane and application thereof. The method has simple preparation process, low material price, is suitable for industrial production, and the obtained composite membrane has the characteristics of high strength and high flux, stable flux in the oil-water separation process, excellent separation performance, and wide industrial application value in oil-water separation, sewage treatment and marine oil leakage.

[0110] It should be noted that the above examples are only used to illustrate the technical solutions of the application and are not limiting. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the application, and they should be covered in the scope of the application.

Claims

1. A method for preparing a surface-coated cellulose composite film, characterized by: The method comprises the steps of: Mixing DMF, ZrCl4 and H2ATA, ultrasonic treatment, adding acetic acid, pouring the prepared solution into an autoclave for high-temperature reaction; After the reaction is completed, the solution is centrifuged to obtain yellow crystalline solid, which is washed with DMF and ethanol, and the obtained yellow crystalline solid is high-temperature baked; The yellow crystalline solid is dispersed in an ethanol solution with ZnO nanoparticles, ultrasonic mixing is performed, and the mixture is dried and ground to obtain a MOF@ZnO material; The MOF@ZnO is dispersed in N-N dimethylacetamide and stirred, polyvinylpyrrolidone is added and continues to be stirred, and an ultrasonic treatment is performed to obtain a mixed solution; Polyvinylidene fluoride powder is added to the mixed solution and stirred to be uniformly mixed, and the mixed solution is left to be degassed to obtain a casting solution; The casting solution is immersed and coated on a carrier, and the carrier after the immersion and coating is placed in a glass sheet and deionized water to obtain an ultrafiltration membrane; The obtained ultrafiltration membrane is soaked in a cellulose solution with a Tris-HCl buffer solution to obtain a MOF@ZnO@Cellulose@PVDF composite separation membrane.

2. The production method according to claim 1, characterized by: The material ratio of the DMF, ZrCl4 and H2ATA is 50 mL:(0.5-2 mmol):(0.5-2 mmol).

3. The production method according to claim 1 or 2, characterized by: The ratio of the acetic acid to the DMF is 5-7 mL:50 mL.

4. The production method according to claim 1, wherein: The prepared solution is poured into an autoclave for high-temperature reaction, wherein the reaction temperature is 120-125 °C, and the reaction time is 12-24 h.

5. The production method according to claim 1, wherein: The yellow crystalline solid obtained after high-temperature baking, wherein the treatment temperature is 80 °C, and the time is 10-12 h.

6. The production method according to claim 1, wherein: The yellow crystalline solid is dispersed in an ethanol solution with ZnO nanoparticles, wherein the material ratio of the MOF material to ZnO is (0.1-0.9):(0.1-0.9).

7. The production method according to claim 1, wherein: The mixed solution, wherein the ratio of the MOF@ZnO, N-N dimethylacetamide and polyvinylpyrrolidone is 0.1 g:40 ml:0.1 g, and the particle size of the MOF@ZnO is 1300 mesh.

8. The production method as claimed in claim 1 or 7, characterized in that: The ratio of the mixed solution to the polyvinylidene fluoride is (30-50) ml:(3-4) g.

9. The production method according to claim 1, wherein: The cellulose solution with the Tris-HCl buffer solution, wherein the pH value of the Tris-HCl buffer solution is 8.5, and the concentration of the cellulose is 80-100 mg / L.

10. Use of the composite membrane prepared according to the method of any one of claims 1 to 9 in oil-water separation, characterized in that: The oil comprises kerosene.

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