A highly permeable - selective cellulose - based nanofiltration membrane, its preparation method and application

Abstract

The present invention discloses a highly permeable - selective cellulose - based nanofiltration membrane, its preparation method and application. The preparation method includes: providing an ultrafiltration membrane as a base layer; immersing the ultrafiltration membrane in an intermediate layer solution containing charged amino acids to form a charged amino acid intermediate layer on the surface of the ultrafiltration membrane; and, forming a cellulose - based polyamide layer on the surface of the intermediate layer by interfacial polymerization reaction, thereby obtaining a highly permeable - selective cellulose - based nanofiltration membrane; wherein, the aqueous solution used in the interfacial polymerization reaction includes cellulose - like substances and diamines, and the organic phase solution includes polyacyl chlorides. The highly permeable - selective cellulose - based nanofiltration membrane in the present invention has excellent pure water permeability and salt rejection rate, and can be widely applied in the fields of drinking water treatment, brine separation, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanofiltration membranes, and particularly relates to a high permeability-selectivity cellulose-based nanofiltration membrane, a preparation method thereof and an application thereof. Background Art

[0002] The water resources on the earth are very limited. Seawater accounts for 97.4% of the total, and fresh water is only 2.6%. Due to human activities or natural environmental changes, the global resource and environmental problems are becoming increasingly severe. The environmental problems mainly related to fresh water resources have become one of the difficulties that people need to solve. The water required by the human body needs certain minerals and trace elements, so the water that can be directly drunk by us humans is extremely scarce. Therefore, it is urgent to solve the drinking water purification crisis.

[0003] At present, there are many technologies for treating seawater resources to obtain water that can be directly drunk by humans. In recent years, membrane separation technology has become a key technology in water treatment technology. Nanofiltration (NF) membrane is a pressure-driven membrane developed based on reverse osmosis separation technology. Because the screening pore size of nanofiltration is about 1 nm and the molecular weight cut-off is between 200 and 1000 Da, it can remove macromolecules with a molecular weight greater than 200 Da, and the rejection rate is above 90%. The operating range of the nanofiltration membrane is between ultrafiltration and reverse osmosis. The molecular weight of the organic matter it intercepts is about 150-500, and the ability to intercept dissolved salts is between 20% and 98%. The corresponding pore size is ≤2 nm, and it has good pore screening effect. The desalination of monovalent anion salt solution is lower than that of high-valent anion solution. Therefore, this nanofiltration technology has been widely applied in wastewater treatment, water softening, food processing, pharmaceutical industry, etc. The existing nanofiltration membranes are usually polyamide nanofiltration membranes, which are often prepared by the interfacial polymerization method. Two highly reactive monomers (aqueous phase amine monomer and oil phase acyl chloride monomer) are dissolved in two immiscible solvents respectively, and an irreversible polycondensation reaction occurs at the interface of the two liquid phases to form a dense-structured polyamide nanofiltration membrane. The commonly used aqueous phase monomers are piperazine (PIP), and the oil phase monomer is 1,3,5-benzenetricarbonyl chloride (TMC). Nanofiltration membranes usually carry out separation and selection under the combined action of multiple separation principles such as Donnan effect, dielectric effect and size screening effect. However, nanofiltration membranes have the drawback of the "trade-off effect" of membrane separation, that is, in the case of better permeability, the selectivity is poor, and in the case of higher selectivity, the permeability is very low. Therefore, it is worth studying to prepare a nanofiltration membrane that breaks the "trade-off effect" and improves the permeability without reducing the selectivity.

[0004] In order to effectively break the "trade-off effect", researchers have made many different studies, including the modification treatment of the base membrane, such as sulfonation hydrophilic treatment of the base membrane, and the addition of aqueous phase additives that have been studied the most, such as MOFs, COFs, surfactants, inorganic nanoparticles such as SiO2 , carbon quantum dots, graphene, carbon nanotubes, etc. However, these additives cannot guarantee to improve the permeability without reducing the selectivity, and inorganic nanoparticles have problems such as easy agglomeration, difficult dispersion, and uneven membranes. Summary of the Invention

[0005] The main object of the present invention is to provide a high-permeability-selectivity cellulose-based nanofiltration membrane, its preparation method and application, so as to overcome the deficiencies of the prior art.

[0006] To achieve the foregoing invention object, the technical solutions adopted by the present invention include:

[0007] An embodiment of the present invention provides a preparation method of a high-permeability-selectivity cellulose-based nanofiltration membrane, which includes:

[0008] Providing an ultrafiltration membrane as a base layer;

[0009] Immersing the ultrafiltration membrane in an intermediate layer solution containing charged amino acids for impregnation treatment, so as to form a charged amino acid intermediate layer on the surface of the ultrafiltration membrane;

[0010] And, forming a cellulose-based polyamide layer on the surface of the intermediate layer by interfacial polymerization reaction, so as to obtain a high-permeability-selectivity cellulose-based nanofiltration membrane; wherein, the aqueous solution used in the interfacial polymerization reaction includes cellulose substances and diamines, and the organic phase solution includes polyacyl chlorides.

[0011] An embodiment of the present invention also provides a high-permeability-selectivity cellulose-based nanofiltration membrane prepared by the foregoing preparation method. The high-permeability-selectivity cellulose-based nanofiltration membrane includes a base layer, a charged amino acid intermediate layer and a cellulose-based polyamide layer stacked in sequence; wherein, the cellulose-based polyamide layer has a wrinkled Turing structure.

[0012] An embodiment of the present invention also provides the use of the foregoing high-permeability-selectivity cellulose-based nanofiltration membrane in the field of drinking water treatment or brine separation.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] (1) The present invention uses a reaction-diffusion mechanism to prepare a high-permeability-selectivity cellulose-based nanofiltration membrane under the dual constraints of the interaction between charged amino acids and cellulose on diamines;

[0015] (2) The amino acids in the present invention are biological macromolecules, with obvious zwitterionic characteristics and controllable charges. Due to different groups carried, the charges in water are different;

[0016] (3) The cellulose in the present invention is easy to obtain and has a low price, making the preparation method of the cellulose-based nanofiltration membrane easier to industrialize;

[0017] (4) The pure water flux of the high-permeability and selective cellulose-based nanofiltration membrane in the present invention reaches 18 LMH bar -1 and above, and the rejection rate of various salts reaches 95% and above. In particular, for high-valent salts, it can be widely used in drinking water treatment, making it easier for people to obtain directly drinkable water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is the infrared characterization diagram of the nanofiltration membrane in Embodiments 1, 2, 4, and 6 of the present invention;

[0020] Figures 2a - 2d It is the SEM diagram of the nanofiltration membrane in Embodiments 1, 2, 4, and 6 of the present invention;

[0021] Figure 3 It is the diagram of the separation performance of the nanofiltration membrane in Embodiments 1, 2, 4, and 6 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] In view of the defects of the prior art, the inventors of this case, through long-term research and a large number of practices, have proposed the technical solution of the present invention, which mainly uses the wrinkled Turing polyamide nanofiltration membrane formation mechanism - reaction-diffusion, and jointly prepares a high-permeability and selective cellulose-based nanofiltration membrane with a charged amino acid as the intermediate layer under dual inhibition.

[0023] The following will clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0024] Specifically, as an aspect of the technical solution of the present invention, a preparation method of a high-permeability and selective cellulose-based nanofiltration membrane includes:

[0025] Providing an ultrafiltration membrane as the base layer;

[0026] Immersing the ultrafiltration membrane in an intermediate layer liquid containing a charged amino acid to form a charged amino acid intermediate layer on the surface of the ultrafiltration membrane;

[0027] And, an interfacial polymerization reaction is used to form a cellulose-based polyamide layer on the surface of the intermediate layer, thereby obtaining a high permeation-selectivity cellulose-based nanofiltration membrane; wherein, the aqueous solution used in the interfacial polymerization reaction includes cellulose substances and diamines, and the organic phase solution includes polyacyl chlorides.

[0028] In some preferred embodiments, the ultrafiltration membrane includes any one or a combination of a polyethersulfone membrane, a polyvinyl chloride membrane, a cellulose triacetate membrane, and a polyvinylidene fluoride ultrafiltration membrane, and is not limited thereto.

[0029] In some preferred embodiments, the charged amino acids include any one or a combination of glycine, glutamic acid, aspartic acid, arginine, and lysine, and are not limited thereto.

[0030] In some preferred embodiments, the cellulose substances are cellulose and its derivatives containing hydrophilic active groups, and the cellulose substances include any one or a combination of ethyl cellulose, carboxymethyl cellulose, cellulose nanocrystals, and cellulose powder, and are not limited thereto.

[0031] Furthermore, the cellulose nanocrystals, cellulose powder, etc. all contain hydrophilic active groups.

[0032] In some preferred embodiments, the diamines include any one or a combination of ethylenediamine, hexamethylenediamine, piperazine, m-phenylenediamine, p-phenylenediamine, and polyethyleneimine, and are not limited thereto.

[0033] In some preferred embodiments, the polyacyl chlorides include any one or a combination of trimellitic acid trichloride, 3,4′,5-biphenyltricarbonyl chloride, 3,3′,5,5′-biphenyltetracarbonyl chloride, isophthaloyl chloride, 5-isocyanatoisophthaloyl chloride, and 5-oxaloyl chloride isophthaloyl chloride, and are not limited thereto.

[0034] In some preferred embodiments, the preparation method specifically includes:

[0035] Pretreat the ultrafiltration membrane;

[0036] Mix the charged amino acids with water to form an intermediate layer solution;

[0037] And, immerse the ultrafiltration membrane obtained by pretreatment in the intermediate layer solution for 8 - 10 min, then take it out and remove the excess solution, thereby forming a charged amino acid intermediate layer on the surface of the ultrafiltration membrane.

[0038] Furthermore, the mass ratio of the charged amino acids to water in the intermediate layer solution is 0.01 - 0.03:100.

[0039] In some preferred embodiments, the preparation method specifically includes:

[0040] Mix the cellulose-based material, diamine, and water to form an aqueous solution.

[0041] Mix the polyvalent acyl chloride with an organic phase solvent to form an organic phase solution.

[0042] And, place the obtained ultrafiltration membrane successively in the aqueous solution and the organic phase solution for interfacial polymerization reaction, and then carry out curing treatment to prepare a high-permeability and selective cellulose-based nanofiltration membrane.

[0043] Furthermore, the concentration of diamine in the aqueous solution is 0.20 - 0.40 wt%.

[0044] Furthermore, the concentration of the cellulose-based material in the aqueous solution is 0.005 - 0.010 wt%.

[0045] Furthermore, the concentration of polyvalent acyl chloride in the organic phase solution is 0.10 - 0.30 wt%.

[0046] Furthermore, the mass ratio of the cellulose-based material to diamine is 0.005 - 0.010:0.20 - 0.40.

[0047] Furthermore, the temperature used for the curing treatment is 60 - 80 °C, and the time is 8 - 10 min.

[0048] In some preferred embodiments, the preparation method of the high-permeability and selective cellulose-based nanofiltration membrane comprises the following steps:

[0049] (1) Ultrafiltration membrane pretreatment: At room temperature, soak the polyethersulfone ultrafiltration membrane in 75% anhydrous ethanol, and then wash it with deionized water.

[0050] (2) Mix different charged amino acids in a certain proportion to obtain an intermediate layer solution; Optimal condition: The ratio of the charged amino acid in the intermediate layer solution to water is 0.01 - 0.03 wt%.

[0051] (3) Mix the cellulose and its derivatives with hydrophilic active groups and a quantitative diamine solution in a certain proportion to obtain an aqueous phase solution; Optimal condition: The mass fraction ratio of cellulose and its derivatives to diamine monomer is 0.005 - 0.010:0.20 - 0.40.

[0052] (4) Mix the polyvalent acyl chloride with an organic phase solvent and stir until completely dissolved to prepare an organic phase solution.

[0053] (5) By using the interfacial polymerization method, the pretreated ultrafiltration membrane is immersed in the intermediate layer solution for a period of time. After removing the excess solution, it is then immersed in the aqueous solution, and the excess aqueous solution on the surface is removed. Then it is placed in the organic phase solution for reaction. Finally, the reacted membrane is put into a vacuum drying oven for curing treatment to obtain a cellulose nanofiltration membrane with charged amino acids as the intermediate layer.

[0054] In this application, the charged amino acid intermediate layer and the cellulose-based polyamide layer are deposited on one side of the ultrafiltration membrane.

[0055] Another aspect of the embodiments of the present invention also provides a high permeability-selective cellulose-based nanofiltration membrane prepared by the aforementioned preparation method. The high permeability-selective cellulose-based nanofiltration membrane includes a substrate layer, a charged amino acid intermediate layer, and a cellulose-based polyamide layer that are stacked in sequence; wherein, the cellulose-based polyamide layer has a wrinkled Turing structure.

[0056] Further, the thickness of the cellulose-based polyamide layer is 100 nanometers.

[0057] The nanofiltration membrane with a Turing structure is usually formed by interfacial polymerization into uniform nodular or striped shapes, and only nodular structures are observed in existing commercial membranes. Based on interfacial polymerization to prepare polyamide nanofiltration membranes, the preparation of wrinkled polyamide nanofiltration membranes usually utilizes the reaction-diffusion mechanism, which is the competition between two factors. One is called the "activator", and the other is called the "inhibitor". In order to inhibit the autocatalytic performance of the activator, the key is that the two factors must have a large diffusion rate difference, so that there will be a large morphological difference, that is, by adding a substance with a certain interaction (hydrogen bond and electrostatic interaction) with the aqueous diamine monomer, the diffusion rate of the aqueous phase is inhibited, and a certain diffusion rate difference is formed.

[0058] The characteristics of the method provided by the present invention are to select green and safe cellulose and its derivatives and biological macromolecule amino acids as raw materials for preparation. Different charged amino acids have different charges in the aqueous solution (alkaline), and amino acids with different charges have different hydrogen bond and electrostatic interactions with diamine, inhibiting the diffusion of the aqueous phase to the oil phase and fixing the diamine monomer on the substrate. Also, due to the addition of hydrophilic active group-containing cellulose into the aqueous phase of interfacial polymerization, the hydrophilic groups and diamine in the aqueous phase form hydrogen bond and electrostatic interactions, which can increase the viscosity of the aqueous phase and at the same time reduce the diffusion rate of the aqueous phase to the oil phase. Under the dual constraints, the diffusion rate of the aqueous diamine is significantly reduced, resulting in the formation of a wrinkled polyamide layer. The hydrogen bond effect and the dispersed and balanced aqueous solution make the prepared polyamide nanofiltration membrane have a wrinkled polyamide layer, and both the pure water permeability and the salt rejection rate are greatly improved. The present invention jointly prepares a high permeability-selective cellulose-based nanofiltration membrane with charged amino acids as the intermediate layer under the dual constraints of amino acids and cellulose on the diamine monomer, which can be widely used in fields such as drinking water treatment and brine separation.

[0059] In some preferred embodiments, the pure water flux of the high permeability - selective cellulose - based nanofiltration membrane is above 15 LMH bar -1 or more.

[0060] In some preferred embodiments, the salt rejection rate of the high permeability - selective cellulose - based nanofiltration membrane is above 90%.

[0061] Another aspect of the embodiments of the present invention also provides the use of the aforementioned high permeability - selective cellulose - based nanofiltration membrane in the field of drinking water treatment or brine separation.

[0062] The technical solutions of the present invention will be further described in detail below in conjunction with several preferred embodiments and the accompanying drawings. These embodiments are implemented on the premise of the technical solutions of the invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0063] In the following embodiments, the experimental materials used, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0064] Example 1

[0065] A method for preparing a high permeability - selective cellulose - based nanofiltration membrane with a charged amino acid as the intermediate layer is formed in the present invention, including the following steps:

[0066] Step 1. Ultrafiltration membrane pretreatment: At room temperature, soak the polyethersulfone ultrafiltration membrane in 75% anhydrous ethanol and then wash it with deionized water;

[0067] Step 2. Prepare an intermediate layer solution by mixing lysine with a positive charge in a mass fraction of 0.10%;

[0068] Step 3. Mix cellulose nanocrystals and anhydrous piperazine in a mass fraction ratio of 0.005:0.35 and stir until completely dissolved to prepare an aqueous solution.

[0069] Step 4. Mix trimellitic acid chloride in a mass fraction of 0.25% in a n - hexane solvent and stir until completely dissolved to prepare an organic phase solution;

[0070] Step 5. Using the interfacial polymerization method, after putting the pretreated ultrafiltration membrane into the intermediate layer solution for a period of time, remove the excess solution on the surface and then immerse it in the aqueous solution for a period of time. Remove the excess aqueous solution on the surface, put it into the organic phase solution for reaction, and finally put the reacted membrane into a 60 °C vacuum drying oven for curing treatment to obtain a cellulose - based nanofiltration membrane with an amino acid as the intermediate layer; The infrared characterization diagram of the nanofiltration membrane is as Figure 1 shown, and the SEM diagram is as Figure 2a shown, and the separation performance is asFigure 3 As shown. Test was carried out with a magnesium sulfate solution with a concentration of 2000 ppm under a pressure of 0.4 MPa. The water flux of this membrane was 19.6 LMHbar -1 , and the rejection rate of magnesium sulfate was 96.4%.

[0071] Example 2

[0072] Step 1. Ultrafiltration membrane pretreatment: At room temperature, soak the polyvinylidene fluoride ultrafiltration membrane in 75% anhydrous ethanol, and then wash it with deionized water;

[0073] Step 2. Prepare the intermediate layer solution by mixing lysine with a positive charge at a mass fraction of 0.10%;

[0074] Step 3. Mix cellulose nanocrystals and anhydrous piperazine at a mass fraction ratio of 0.005:0.35 and stir until completely dissolved to prepare an aqueous solution.

[0075] Step 4. Mix trimellitic acid chloride in n-hexane solvent at a mass fraction of 0.25% and stir until completely dissolved to prepare an organic phase solution;

[0076] Step 5. Adopt the interfacial polymerization method. After putting the pretreated ultrafiltration membrane into the intermediate layer solution for a period of time, remove the excess solution on the surface and then immerse it in the aqueous solution for a period of time. Remove the excess aqueous solution on the surface, put it into the organic phase solution for reaction, and finally put the reacted membrane into a 60 °C vacuum drying oven for curing treatment to obtain a cellulose-based nanofiltration membrane with amino acid as the intermediate layer; The infrared characterization diagram of the nanofiltration membrane is as Figure 1 shown, the SEM diagram is as Figure 2b shown, and the separation performance is as Figure 3 shown. Test was carried out with a magnesium sulfate solution with a concentration of 2000 ppm under a pressure of 0.4 MPa. The water flux of this membrane was 15.8 LMHbar -1 , and the rejection rate of magnesium sulfate was 91.3%.

[0077] Example 3

[0078] Steps 1, 3, 4 and 5 are the same as those in Example 1. The only difference is that in Step 2, lysine with a negative charge is replaced by glutamic acid with a negative charge to obtain a cellulose-based nanofiltration membrane with amino acid as the intermediate layer; Test was carried out with a magnesium sulfate solution with a concentration of 2000 ppm under a pressure of 0.4 MPa. The water flux of this membrane was 13.2 LMHbar -1 , and the rejection rate of magnesium sulfate was 92.2%.

[0079] Example 4

[0080] Steps 1, 2, 4, and 5 are the same as those in Example 1. The only difference is that in Step 3, the mass fraction ratio of cellulose nanocrystals to anhydrous piperazine is changed to 0.010:0.30, obtaining a cellulose-based nanofiltration membrane with an amino acid as the intermediate layer; the infrared characterization diagram of the nanofiltration membrane is as shown in Figure 1 shown, and the SEM diagram is as shown in Figure 2c shown, and the separation performance is as shown in Figure 3 shown. It was tested with a magnesium sulfate salt solution with a concentration of 2000 ppm under a pressure of 0.4 MPa. The water flux of this membrane is 16.5 LMHbar -1 , and the rejection rate of magnesium sulfate is 92.4%.

[0081] Example 5

[0082] Steps 1, 2, 4, and 5 are the same as those in Example 1. The only difference is that in Step 3, the mass fraction ratio of cellulose nanocrystals to anhydrous piperazine is changed to 0.008:0.40, obtaining a cellulose-based nanofiltration membrane with an amino acid as the intermediate layer; it was tested with a magnesium sulfate salt solution with a concentration of 2000 ppm under a pressure of 0.4 MPa. The water flux of this membrane is 17.3 LMHbar -1 , and the rejection rate of magnesium sulfate is 95.1%.

[0083] Example 6

[0084] Steps 1, 2, 3, and 5 are the same as those in Example 1. The only difference is that in Step 4, the mass fraction of trimellitic acid chloride in n-hexane solvent is changed to 0.20%, obtaining a cellulose-based nanofiltration membrane with an amino acid as the intermediate layer; the infrared characterization diagram of the nanofiltration membrane is as shown in Figure 1 shown, and the SEM diagram is as shown in Figure 2d shown, and the separation performance is as shown in Figure 3 shown. It was tested with a magnesium sulfate salt solution with a concentration of 2000 ppm under a pressure of 0.4 MPa. The water flux of this membrane is 15.6 LMHbar -1 , and the rejection rate of magnesium sulfate is 92.6%.

[0085] Example 7

[0086] Steps 1, 2, 3, and 4 are the same as those in Example 1. The only difference is that in Step 5, the heat treatment temperature is changed to 80 °C, obtaining a cellulose-based nanofiltration membrane with an amino acid as the intermediate layer; it was tested with a magnesium sulfate salt solution with a concentration of 2000 ppm under a pressure of 0.4 MPa. The water flux of this membrane is 15.2 LMHbar -1 , and the rejection rate of magnesium sulfate is 94.2%.

[0087] Comparative Example 1

[0088] The method was the same as that of Example 1, except that: the middle layer liquid was missing; the obtained cellulose-based nanofiltration membrane was tested with a magnesium sulfate solution with a concentration of 2000 ppm under a pressure of 0.4 MPa, and the water flux of the membrane was 14.9 LMHbar -1 , and the rejection rate of magnesium sulfate was 91.0%.

[0089] Comparative Example 2

[0090] The method was the same as that of Example 1, except that: Step 2 was omitted, and positively charged lysine was placed in the aqueous solution. The obtained composite nanofiltration membrane was tested with a magnesium sulfate solution with a concentration of 2000 ppm under a pressure of 0.4 MPa, and the water flux of the membrane was 13.2 LMHbar -1 , and the rejection rate of magnesium sulfate was 90.4%.

[0091] Comparative Example 3

[0092] The method was the same as that of Example 1, except that: cellulose nanocrystals were missing in the aqueous solution. The obtained nanofiltration membrane was tested with a magnesium sulfate solution with a concentration of 2000 ppm under a pressure of 0.4 MPa, and the water flux of the membrane was 9.8 LMHbar -1 , and the rejection rate of magnesium sulfate was 89.9%.

[0093] In addition, the inventors of this case also referred to the foregoing examples and conducted tests with other raw materials, process operations, and process conditions described in this specification, and all obtained relatively ideal results.

[0094] It should be understood that the technical solution of the present invention is not limited to the limitations of the above specific implementation cases. Any technical deformation made according to the technical solution of the present invention without departing from the purpose of the present invention and the scope protected by the claims falls within the protection scope of the present invention.

Claims

1. A method for preparing a highly permeable-selective cellulose-based nanofiltration membrane, characterized in that: include: providing an ultrafiltration membrane as a substrate layer; The ultrafiltration membrane is immersed in an intermediate layer liquid containing charged amino acids, so as to form a charged amino acid intermediate layer on the surface of the ultrafiltration membrane; wherein the content of charged amino acids in the intermediate layer liquid containing charged amino acids is 0.1wt%; and the charged amino acids include any one or more combinations of glycine, aspartic acid, arginine, and lysine; And, forming a cellulose-based polyamide layer on the surface of the intermediate layer by interfacial polymerization reaction, thereby preparing a high permeability-selective cellulose-based nanofiltration membrane; wherein the aqueous phase solution used in the interfacial polymerization reaction includes a cellulose-based substance and a diamine, and the organic phase solution includes a polyacyl chloride, and the cellulose-based substance is cellulose and its derivatives containing hydrophilic active groups, and the cellulose-based substance includes any one or more combinations of ethyl cellulose, cellulose nanocrystals, and cellulose powder; The high permeability-selectivity cellulose-based nanofiltration membrane comprises a base layer, a charged amino acid middle layer and a cellulose-based polyamide layer which are stacked in sequence; wherein the cellulose-based polyamide layer has a wrinkled Turing structure.

2. The preparation method according to claim 1, characterized in that: The ultrafiltration membrane includes any one or more combinations of polyethersulfone membrane, polyvinyl chloride membrane, triacetylcellulose membrane, and polyvinylidene fluoride ultrafiltration membrane; And / or, the diamine includes any one or more combinations of ethylenediamine, hexamethylenediamine, piperazine, m-phenylenediamine, p-phenylenediamine, and polyethyleneimine; And / or, the polyacid chloride includes any one or more combinations of trimesoyl chloride, 3,4′,5-biphenyltrichloride, 3,3′,5,5′-biphenyltetrachloride, isophthaloyl chloride, 5-isocyanate isophthaloyl chloride, and 5-oxocarbonyl isophthaloyl chloride.

3. The preparation method according to claim 1, characterized in that: Specifically include: Pre-treating the ultrafiltration membrane; Mixing charged amino acids with water to form an intermediate layer liquid; Also, the ultrafiltration membrane obtained by the pretreatment is immersed in the intermediate layer liquid for 8 to 10 minutes, and then the excess solution is taken out and removed, thereby forming a charged amino acid intermediate layer on the surface of the ultrafiltration membrane.

4. The preparation method according to claim 1, characterized in that: Specifically include: Mixing the cellulose material, the diamine and water to form an aqueous solution; mixing a polyacid chloride with an organic phase solvent to form an organic phase solution; Furthermore, the obtained ultrafiltration membrane is placed in an aqueous solution and an organic solution in sequence for interfacial polymerization reaction, and then solidified to obtain a high permeability-selectivity cellulose-based nanofiltration membrane.

5. The preparation method according to claim 4, characterized in that: The concentration of the diamine in the aqueous phase solution is 0.20-0.40 wt %; and / or, the concentration of the cellulose substance in the aqueous solution is 0.005-0.010 wt %; and / or, the concentration of the polyacid chloride in the organic phase solution is 0.10-0.30wt%; And / or, the mass ratio of the cellulose material to the diamine is 0.005-0.010:0.20-0.

40.

6. The preparation method according to claim 4, characterized in that: The curing process is performed at a temperature of 60 to 80° C. and for a time of 8 to 10 minutes.

7. A highly permeable-selective cellulose-based nanofiltration membrane prepared by the preparation method according to any one of claims 1 to 6.

8. The highly permeable-selective cellulose-based nanofiltration membrane according to claim 7, characterized in that: The pure water flux of the highly permeable-selective cellulose-based nanofiltration membrane is 15 LMH bar. -1 above.

9. The highly permeable-selective cellulose-based nanofiltration membrane according to claim 7, characterized in that: The high permeability-selectivity cellulose-based nanofiltration membrane has a salt retention rate of more than 90%.

10. Use of the highly permeable-selective cellulose-based nanofiltration membrane according to any one of claims 7 to 9 in the field of drinking water treatment or salt water separation.

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