A high desalination polyamide reverse osmosis membrane, a preparation method and application thereof

Abstract

The application discloses a kind of high desalination polyamide reverse osmosis membranes and its preparation method and application, the method includes the following steps: step one, preparation support base film;Step two, on support base film by the interface polymerization of water phase polyamine and organic phase polyacyl chloride Form polyamide separation layer;Step three, using containing condensing agent, polar mixed solvent of polyaminopropyl biguanide is carried out surface treatment to polyamide separation layer;Optionally step four, after surface treatment, membrane piece is immersed in glycerol solution and soaked, after taking out, dry, obtain the high desalination polyamide reverse osmosis membrane.This method is modified by polyaminopropyl biguanide with condensing agent to the polyamide desalination layer of reverse osmosis membrane, improves crosslinking density, and cooperates the scheme of polar solvent swelling, makes desalination rate greatly improve while membrane flux also significantly improves, this method can improve the problem that flux and desalination rate cannot be considered in prior art.

Description

Technical Field

[0001] This invention relates to a reverse osmosis membrane manufacturing technology, and more particularly to a high desalination polyamide reverse osmosis membrane, its preparation method, and its application. Background Technology

[0002] Reverse osmosis membranes can be used for various fluid separations. Currently, the most widely used reverse osmosis membrane is the cross-linked aromatic polyamide reverse osmosis membrane. Typically, polyamide reverse osmosis membranes are prepared by first forming a polyamide layer through an interfacial polycondensation reaction between polyfunctional amines and polyfunctional acyl chlorides on the surface of a polysulfone-supported membrane, followed by certain post-processing. The resulting polyamide layer is crucial to influencing water permeability and salt rejection rate; therefore, optimizing and adjusting the polyamide layer can yield the desired membrane performance.

[0003] To achieve high desalination performance in reverse osmosis membranes, current patents and literature primarily focus on optimizing the porous support layer and the polyamide layer. In particular, the optimization of the polyamide layer has been extensively studied, with most research concentrating on adding different types of additives to either polyamine solutions or polyacrylamide chloride coating solutions to improve the polyamide layer structure and thus enhance the desalination rate. Examples are provided below.

[0004] Patent CN111201267A discloses adding a pyrimidine-based compound or a purine-based compound to an aqueous amine solution. By adding the pyrimidine-based compound or the purine-based compound during interfacial polymerization, the terminal groups of the additive can form covalent bonds with the functional groups of the TMC, which can significantly improve the salt rejection rate. However, while improving the desalination rate, this patent results in a certain degree of flux loss. Patent CN104781001A discloses coating a second organic solvent with a volatility lower than that of the first organic solvent onto the polyamide active layer to induce an additional interfacial polymerization reaction between the remaining acyl chloride and the unreacted portion of the amine compound on the polyamide active layer, thereby improving the density of reverse osmosis. While improving the desalination rate, it only achieves a minimal decrease in membrane flux.

[0005] It can be seen that although some technical solutions for improving desalination rate have been developed in the existing technology, these technical solutions generally suffer from membrane flux loss while improving the desalination rate, and it is difficult to improve both desalination rate and membrane flux at the same time. Summary of the Invention

[0006] The purpose of this invention is to provide a high-desalination polyamide reverse osmosis membrane to improve the problem that flux and desalination rate cannot be simultaneously achieved in the prior art.

[0007] Another object of the present invention is to provide a method for preparing such a high-desalination polyamide reverse osmosis membrane.

[0008] Another object of the present invention is to provide the application of such high-desalination polyamide reverse osmosis membranes in water treatment components, apparatuses and / or water treatment methods.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A method for preparing a high-desalination polyamide reverse osmosis membrane includes the following steps:

[0011] Step 1: Prepare the supporting substrate membrane;

[0012] Step 2: A polyamide separation layer is formed on the supporting base membrane through an interfacial polymerization reaction between aqueous polyamine and organic polyacrylamide chloride;

[0013] Step 3: Perform surface treatment on the polyamide release layer using a polar mixed solvent containing a condensing agent and polyurethane biguanide;

[0014] Optionally, in step four, the surface-treated membrane is immersed in a glycerol solution for soaking, then removed and dried to obtain the reverse osmosis membrane.

[0015] In a preferred embodiment of the present invention, in step one, the casting liquid is coated onto the substrate material, immediately immersed in a coagulation bath to form a film through phase transformation, and then cleaned to obtain a supporting substrate film.

[0016] Preferably, the effective component of the casting solution is one or more of polysulfone, polyethersulfone, and polyacrylonitrile, and the solvent is N,N-dimethylformamide;

[0017] Preferably, the mass concentration of the effective component in the casting solution is 15-18%.

[0018] In a preferred embodiment of the present invention, in step one, the base material is a non-woven fabric, preferably one or more of polyester fiber and polyamide fiber;

[0019] Preferably, the coagulation bath is water; the coagulation bath temperature is 5–30°C, and the immersion time is 2–5 minutes.

[0020] In a preferred embodiment of the present invention, the polyamine is an aromatic amine and / or aliphatic amine containing at least two primary amino groups, preferably one or more of o-phenylenediamine, m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, p-phenylenediamine, m-phenylenediamine, 1,3,5-triaminobenzene, ethylenediamine, and piperazine.

[0021] Preferably, the mass concentration of the polyamine is 0.5 to 5.0 wt%.

[0022] In a preferred embodiment of the present invention, the polyacryl chloride is selected from aromatic polyacryl chlorides and / or aliphatic polyacryl chlorides, preferably one or more of pyromellitic trimethylolpropionate chloride, terephthaloyl chloride, isophthaloyl chloride, naphthalenedicarboxyl chloride, and adipyl chloride;

[0023] Preferably, the mass concentration of the polyacrylamide chloride is 0.01–0.5 wt%.

[0024] Preferably, the organic phase solvent of the polyacrylamide chloride is one or more of hexane, heptane, decane, Isopar G, and Isopar L.

[0025] In a preferred embodiment of the present invention, in step two, the conditions for the interfacial polymerization reaction are: temperature 15–35°C and time 10–120 s.

[0026] As a specific method for interfacial polymerization, any known operating procedure can be adopted. For example, the supporting base membrane can be immersed in an aqueous phase containing polyamines for 10 to 300 seconds, and after removal, the residual aqueous phase on the surface can be removed. Then, an organic phase containing polyacrylamide chlorides can be poured onto the membrane surface to carry out the interfacial polymerization reaction. This is not intended to limit the present invention and will not be elaborated here.

[0027] In a preferred embodiment of the present invention, in step three, the surface treatment conditions are: temperature 20-30°C and time 5-120s.

[0028] In a preferred embodiment of the present invention, the condensing agent is one or more of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1,3-di(2,2-dimethyl-1,3-dioxolane-4-ylmethyl)carbodiimide, and 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride (DMT-MM);

[0029] The polar mixed solvent is a mixture of at least one of the following polar solvents: methanol, ethanol, isopropanol, acetone, ethyl acetate, ethylene glycol methyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and thionyl chloride with water.

[0030] Preferably, based on a total mass of 100 wt% of the polar mixed solvent containing the condensing agent and polyurethane biguanide, the mass concentration of the condensing agent is 0.01–3.0 wt%, preferably 0.05–2.0 wt%, the mass concentration of the polyurethane biguanide is 0.01–5.0 wt%, preferably 0.1–3.0 wt%, and the mass concentration of the polar solvent is 60–90 wt%, preferably 70–90 wt%.

[0031] In step three, the surface treatment method can be to pour a polar mixed solvent containing condensing agent and polyurethane biguanide onto the polyamide separation layer formed in step two, keep it for a certain period of time, then pour off the excess solution and wash with water.

[0032] In a preferred embodiment of the present invention, in step four, the mass concentration of the glycerol solution is 5-10 wt%, and the soaking and post-soaking treatment time is 30-180 s.

[0033] The application of a high-desalination polyamide reverse osmosis membrane prepared according to the method described above in water treatment components, devices, and / or water treatment methods. The "water treatment component or device" can be any component or device equipped with the high-desalination polyamide reverse osmosis membrane of the present invention that can be used in a water treatment process. "Application in a water treatment component or device" includes application to a component or device product equipped with the high-desalination polyamide reverse osmosis membrane of the present invention, and also includes application to the preparation of such a component or device product. The component can be, for example, a spiral wound membrane module and a disc tube flat sheet membrane module. The device can be, for example, a household / commercial reverse osmosis water purifier, an industrial boiler feedwater reverse osmosis pure water device, an industrial wastewater reuse reverse osmosis device, and a seawater desalination device. The water treatment method can be, for example, methods for drinking water production, wastewater reuse, seawater desalination, and beverage concentration.

[0034] This invention modifies the polyamide desalination layer of a reverse osmosis membrane by using polyaminopropyl biguanide in combination with a condensing agent to increase the crosslinking density. In addition, it uses a polar solvent swelling scheme to significantly improve the desalination rate and membrane flux. This method can solve the problem that flux and desalination rate cannot be achieved simultaneously in the prior art.

[0035] The preparation method of the high desalination polyamide reverse osmosis membrane of the present invention is simple and easy to implement and scale up. The prepared reverse osmosis membrane can maintain a high desalination rate and membrane flux for a long time and can be applied to water treatment fields such as household water purification, municipal drinking water, and food and beverage. Detailed Implementation

[0036] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0037] Unless otherwise specified, the raw materials used in the following examples or comparative examples are all commercially available conventional raw materials. The main raw material information is shown in Table 1 below.

[0038] Table 1. Information on Main Raw Materials

[0039]

[0040]

[0041]

[0042]

[0043] The following describes the methods used or that may be used in the embodiments or comparative examples of the present invention:

[0044] 1. Evaluation of desalination rate and permeability flux

[0045] Desalination rate and permeate flux are two important parameters for evaluating the separation performance of reverse osmosis membranes. This invention evaluates the separation performance of reverse osmosis membranes according to GB / T32373-2015 "Test Methods for Reverse Osmosis Membranes".

[0046] Desalination rate (R) is defined as: under certain operating conditions, the salt concentration (C) of the feed solution... f ) and the salt concentration in the permeate (C p The difference between the two is then divided by the feed solution salt concentration (C). f ), as in formula (1).

[0047]

[0048] Permeation flux is defined as the volume of water that permeates through a unit membrane area per unit time under certain operating conditions, and its unit is L·m. -2 ·h -1 .

[0049] The operating conditions used for the reverse osmosis membrane performance determination in this invention are as follows: the feed solution is a 1500ppm sodium chloride aqueous solution, the solution pH is 7.5±0.5, the operating pressure is 150psi, and the operating temperature is 25±1℃.

[0050] Example 1

[0051] A 16.5 wt% N,N-dimethylformamide solution of polysulfone resin was prepared as the casting solution. The filtered and degassed casting solution was then uniformly coated onto a polyester nonwoven fabric. The fabric was immediately immersed in a coagulation bath of deionized water at a temperature of 25°C for 3 minutes. After phase inversion, the film was formed and then washed with water at 75°C for 2 minutes to obtain the supporting base film.

[0052] The prepared support membrane was immersed in a 2.5 wt% m-phenylenediamine aqueous solution for 30 seconds. Then, it was removed and gently squeezed with a pressure roller to remove the excess aqueous phase remaining on the surface. After that, it was reacted with a 0.12 wt% trimesoyl chloride n-decane solution at 25°C for 30 seconds. The excess n-decane solution was poured off, and the membrane was evenly blown with an air knife until there was no residual solvent on the membrane surface. Immediately, an aqueous solution containing 0.5 wt% polyurethane biguanide, 0.2 wt% condensing agent DMT-MM, and 90 wt% ethanol was coated. The surface was treated at 25°C for 120 seconds. After pouring off the excess solution, it was washed with water and then immersed in an 8 wt% glycerol aqueous solution for 30 seconds. After removal, the excess glycerol on both sides was removed with an air knife, and the membrane was dried in a 70°C oven for 6 minutes to obtain a high desalination polyamide reverse osmosis membrane.

[0053] Example 2

[0054] A 15wt% N,N-dimethylformamide solution of polysulfone resin was prepared as the casting solution. The filtered and degassed casting solution was then uniformly coated onto a polyester nonwoven fabric. The fabric was immediately immersed in a coagulation bath of deionized water at a temperature of 25°C for 3 minutes. After phase inversion, the film was formed. The film was then washed with water at 75°C for 2 minutes to obtain the supporting base film.

[0055] The prepared support membrane was immersed in an aqueous solution of 0.8 wt% p-phenylenediamine for 150 s. Then, it was removed and gently squeezed with a pressure roller to remove excess aqueous phase remaining on the surface. After that, it was reacted with an Isopar G solution of 0.1 wt% isophthaloyl chloride at 20 °C for 90 s. The excess Isopar G solution was poured off, and the membrane was evenly swept with an air knife until no solvent remained on the surface. Immediately, an aqueous solution containing 0.1 wt% polyurethane biguanide, 0.5 wt% condensing agent 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and 60 wt% tetrahydrofuran was coated. The surface was treated at 25 °C for 90 s. After pouring off the excess solution, it was washed with water and then immersed in an 8 wt% glycerol aqueous solution for 30 s. After removal, excess glycerol on both sides was removed with an air knife, and the membrane was dried in a 70 °C oven for 6 min to obtain a high desalination polyamide reverse osmosis membrane.

[0056] Example 3

[0057] Prepare an 18wt% N,N-dimethylformamide solution of polysulfone resin as the casting solution; then uniformly coat the filtered and degassed casting solution onto a polyester nonwoven fabric; immediately immerse it in a coagulation bath of deionized water at a temperature of 25°C for 3 minutes, and form a membrane through phase inversion. Then, soak and wash it in 75°C water for 2 minutes to obtain the supporting base membrane.

[0058] The prepared support membrane was immersed in a 4.5 wt% aqueous solution of 2,5-diaminotoluene for 10 seconds. Then, it was removed and gently squeezed with a pressure roller to remove excess aqueous phase remaining on the surface. After that, it was reacted with a 0.25 wt% phthaloyl chloride n-decane solution at 35°C for 10 seconds. The excess n-decane solution was discarded, and the membrane was evenly swept with an air knife until no solvent remained on the surface. Immediately, an aqueous solution containing 1.0 wt% polyaminopropyl biguanide, 1.0 wt% condensing agent 1,3-bis(2,2-dimethyl-1,3-dioxolane-4-ylmethyl)carbodiimide, and 80 wt% ethylene glycol methyl ether was applied. The surface was treated at 30°C for 60 seconds. After discarding the excess solution, it was washed with water and then immersed in an 8 wt% glycerol aqueous solution for 30 seconds. After removal, excess glycerol on both sides was removed with an air knife, and the membrane was dried in a 70°C oven for 6 minutes to obtain a high-desalination polyamide reverse osmosis membrane.

[0059] Example 4

[0060] A 16.5 wt% N,N-dimethylformamide solution of polysulfone resin was prepared as the casting solution. The filtered and degassed casting solution was then uniformly coated onto a polyester nonwoven fabric. The fabric was immediately immersed in a coagulation bath of deionized water at a temperature of 25°C for 3 minutes. After phase inversion, the film was formed and then washed with water at 75°C for 2 minutes to obtain the supporting base film.

[0061] The prepared support membrane was immersed in a 1.5 wt% aqueous solution of 2,6-diaminotoluene for 60 seconds. Then, it was removed and gently squeezed with a pressure roller to remove excess aqueous phase remaining on the surface. After that, it was reacted with a 0.07 wt% solution of trimesoyl chloride in n-decane at 30°C for 120 seconds. The excess n-decane solution was discarded, and the membrane was evenly swept with an air knife until no solvent remained on the surface. Immediately, an aqueous solution containing 3.0 wt% polyaminopropyl biguanide, 0.05 wt% condensing agent DMT-MM, and 85 wt% N,N-dimethylformamide was coated. The surface was treated at 25°C for 10 seconds. After discarding the excess solution, it was washed with water and then immersed in an 8 wt% glycerol aqueous solution for 30 seconds. After removal, excess glycerol on both sides was removed with an air knife, and the membrane was dried in a 70°C oven for 6 minutes to obtain a high-desalination polyamide reverse osmosis membrane.

[0062] Example 5

[0063] A 16.5 wt% N,N-dimethylformamide solution of polysulfone resin was prepared as the casting solution. The filtered and degassed casting solution was then uniformly coated onto a polyester nonwoven fabric. The fabric was immediately immersed in a coagulation bath of deionized water at a temperature of 25°C for 3 minutes. After phase inversion, the film was formed and then washed with water at 75°C for 2 minutes to obtain the supporting base film.

[0064] The prepared support membrane was immersed in a 3.1 wt% aqueous solution of 1,3,5-triaminobenzene for 60 seconds. Then, it was removed and gently squeezed with a pressure roller to remove excess aqueous phase remaining on the surface. After that, it was reacted with a 0.14 wt% naphthalene dicarboxyl chloride n-decane solution at 20°C for 45 seconds. The excess n-decane solution was discarded, and the membrane was evenly swept with an air knife until no solvent remained on the surface. Immediately, an aqueous solution containing 0.05 wt% polyurethane biguanide, 2.5 wt% condensing agent DMT-MM, and 60 wt% acetone was coated. The surface was treated at 20°C for 100 seconds. After discarding the excess solution, it was washed with water and then immersed in an 8 wt% glycerol aqueous solution for 30 seconds. After removal, excess glycerol on both sides was removed with an air knife, and the membrane was dried in a 70°C oven for 6 minutes to obtain a high-desalination polyamide reverse osmosis membrane.

[0065] Example 6

[0066] A 16.5 wt% N,N-dimethylformamide solution of polysulfone resin was prepared as the casting solution. The filtered and degassed casting solution was then uniformly coated onto a polyester nonwoven fabric. The fabric was immediately immersed in a coagulation bath of deionized water at a temperature of 25°C for 3 minutes. After phase inversion, the film was formed and then washed with water at 75°C for 2 minutes to obtain the supporting base film.

[0067] The prepared support membrane was immersed in a 2.0 wt% m-phenylenediamine aqueous solution for 30 seconds. Then, it was removed and gently squeezed with a pressure roller to remove excess aqueous phase remaining on the surface. After that, it was reacted with a 0.11 wt% trimesoyl chloride n-hexane solution at 25°C for 30 seconds. The excess n-hexane solution was poured off, and the membrane was evenly swept with an air knife until no solvent remained on the membrane surface. Immediately, an aqueous solution containing 0.75 wt% polyurethane biguanide, 0.3 wt% condensing agent DMT-MM, and 85 wt% isopropanol was coated. The surface was treated at 25°C for 50 seconds. After pouring off the excess solution, it was washed with water and then immersed in an 8 wt% glycerol aqueous solution for 30 seconds. After removal, excess glycerol on both sides was removed with an air knife, and the membrane was dried in a 70°C oven for 6 minutes to obtain a high desalination polyamide reverse osmosis membrane.

[0068] Example 7

[0069] A 16.5 wt% N,N-dimethylformamide solution of polysulfone resin was prepared as the casting solution. The casting solution after filtration and degassing was then uniformly coated onto a polyester nonwoven fabric. The fabric was then immediately immersed in a coagulation bath of deionized water at a temperature of 25°C for 3 minutes. After phase inversion, the film was formed and then washed with water at 75°C for 2 minutes to obtain the supporting base film.

[0070] The prepared support membrane was immersed in a 3.5 wt% m-phenylenediamine aqueous solution for 25 seconds. Then, it was removed and gently squeezed with a pressure roller to remove the excess aqueous phase remaining on the surface. After that, it was reacted with a 0.17 wt% trimesoyl chloride n-heptane solution at 25°C for 20 seconds. The excess n-heptane solution was poured off, and the membrane was evenly swept with an air knife until there was no residual solvent on the membrane surface. Immediately, an aqueous solution containing 0.5 wt% polyaminopropyl biguanide, 0.15 wt% condensing agent DMT-MM, and 75 wt% ethyl acetate was coated. The surface was treated at 25°C for 70 seconds. After pouring off the excess solution, it was washed with water and then immersed in an 8 wt% glycerol aqueous solution for 30 seconds. After removal, the excess glycerol on both sides was removed with an air knife, and the membrane was dried in a 70°C oven for 6 minutes to obtain a high desalination polyamide reverse osmosis membrane.

[0071] Example 8

[0072] A 16.5 wt% N,N-dimethylformamide solution of polysulfone resin was prepared as the casting solution. The casting solution after filtration and degassing was then uniformly coated onto a polyester nonwoven fabric. The fabric was then immediately immersed in a coagulation bath of deionized water at a temperature of 25°C for 3 minutes. After phase inversion, the film was formed and then washed with water at 75°C for 2 minutes to obtain the supporting base film.

[0073] The prepared support membrane was immersed in a 2.2 wt% m-phenylenediamine aqueous solution for 40 seconds. Then, it was removed and gently squeezed with a pressure roller to remove the excess aqueous phase remaining on the surface. After that, it was reacted with a 0.12 wt% trimesoyl chloride n-decane solution at 25°C for 30 seconds. The excess n-decane solution was poured off, and the membrane was evenly swept with an air knife until there was no residual solvent on the membrane surface. Immediately, an aqueous solution containing 0.8 wt% polyurethane biguanide, 0.3 wt% condensing agent DMT-MM, and 85 wt% methanol was coated. The surface was treated at 25°C for 90 seconds. After pouring off the excess solution, the membrane was washed with water and then immersed in an 8 wt% glycerol aqueous solution for 30 seconds. After removal, the excess glycerol on both sides was removed with an air knife, and the membrane was dried in a 70°C oven for 6 minutes to obtain a high desalination polyamide reverse osmosis membrane.

[0074] Comparative Example 1

[0075] The reverse osmosis membrane was prepared using essentially the same method as in Example 1, except that the polyamide separation layer was not surface-treated.

[0076] Comparative Example 2

[0077] The reverse osmosis membrane was prepared using essentially the same method as in Example 1, except that the polar mixed solvent used for surface treatment was replaced with an 80wt% aqueous solution of ethanol.

[0078] Comparative Example 3

[0079] The reverse osmosis membrane was prepared using essentially the same method as in Example 1, except that the polar mixed solvent used for surface treatment was replaced with an aqueous solution containing 0.5 wt% polyurethane biguanide and 80 wt% ethanol.

[0080] Comparative Example 4

[0081] The reverse osmosis membrane was prepared using a method essentially the same as in Example 1, except that the polar mixed solvent used for surface treatment was replaced with an aqueous solution containing 0.5 wt% polyurethane biguanide and 0.2 wt% condensing agent DMT-MM.

[0082] The reverse osmosis membranes prepared in each embodiment and comparative example were tested for membrane performance, and the results are shown in Table 2:

[0083] Table 1. Membrane performance test results

[0084]

[0085]

[0086] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-desalination polyamide reverse osmosis membrane, characterized in that, Includes the following steps: Step 1: Prepare the supporting substrate membrane; Step 2: A polyamide separation layer is formed on the supporting base membrane through an interfacial polymerization reaction between aqueous polyamine and organic polyacrylamide chloride; Step 3: The polyamide release layer is surface-treated using a polar mixed solvent containing a condensing agent and polyaminopropyl biguanide; the condensing agent is one or more selected from 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 1,3-di(2,2-dimethyl-1,3-dioxolane-4-ylmethyl)carbodiimide, and 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride. Optionally, in step four, the surface-treated membrane is immersed in a glycerol solution for soaking, then removed and dried to obtain the high-desalination polyamide reverse osmosis membrane.

2. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 1, characterized in that, In step one, the casting solution is coated onto the substrate material, immediately immersed in a coagulation bath to form a film through phase transformation, and then cleaned to obtain the supporting substrate film.

3. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 2, characterized in that, The active ingredient of the casting solution is one or more of polysulfone, polyethersulfone, and polyacrylonitrile, and the solvent is N,N-dimethylformamide.

4. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 2, characterized in that, The mass concentration of the effective component in the casting solution is 15-18%.

5. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 2, characterized in that, In step one, the substrate material is non-woven fabric.

6. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 5, characterized in that, In step one, the base material is one or more of polyester fiber and polyamide fiber.

7. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 5, characterized in that, The coagulation bath is water, the temperature of the coagulation bath is 5-30℃, and the immersion time is 2-5 minutes.

8. The method for preparing a high-desalination polyamide reverse osmosis membrane according to any one of claims 1 to 7, characterized in that, The polyamine is an aromatic amine and / or an aliphatic amine containing at least two primary amino groups.

9. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 8, characterized in that, The polyamine is one or more of o-phenylenediamine, m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, p-phenylenediamine, m-phenylenediamine, 1,3,5-triaminobenzene, ethylenediamine, and piperazine.

10. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 8, characterized in that, The mass concentration of the polyamine is 0.5 to 5.0 wt%.

11. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 8, characterized in that, The polyacyl chloride is selected from aromatic polyacyl chlorides and / or aliphatic polyacyl chlorides.

12. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 11, characterized in that, The polyacryl chloride is selected from one or more of pyromellitic methyl chloride, terephthaloyl chloride, isophthaloyl chloride, naphthalenedicarboxyl chloride, and adipyl chloride.

13. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 11, characterized in that, The mass concentration of the polyacrylamide chloride is 0.01 to 0.5 wt%.

14. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 11, characterized in that, The organic phase solvent of the polyacrylamide chloride is one or more of the following: n-hexane, n-heptane, n-decane, Isopar G, and Isopar L.

15. The method for preparing a high-desalination polyamide reverse osmosis membrane according to any one of claims 1 to 7, characterized in that, In step two, the conditions for the interfacial polymerization reaction are: temperature 15–35°C and time 10–120 s.

16. The method for preparing a high-desalination polyamide reverse osmosis membrane according to any one of claims 1 to 7, characterized in that, In step three, the surface treatment conditions are: temperature 20–30℃ and time 5–120s.

17. The method for preparing a high-desalination polyamide reverse osmosis membrane according to any one of claims 1 to 7, characterized in that, The polar mixed solvent is a mixture of at least one of the following polar solvents: methanol, ethanol, isopropanol, acetone, ethyl acetate, ethylene glycol methyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone, with water.

18. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 17, characterized in that, Based on a total mass of 100 wt% of polar mixed solvent containing condensing agent and polyaminopropyl biguanide, the mass concentration of condensing agent is 0.01–3.0 wt%, the mass concentration of polyaminopropyl biguanide is 0.01–5.0 wt%, and the mass concentration of polar solvent is 60–90 wt%.

19. The method for preparing a high-desalination polyamide reverse osmosis membrane according to claim 18, characterized in that, Based on a total mass of 100 wt% of polar mixed solvent containing condensing agent and polyaminopropyl biguanide, the mass concentration of condensing agent is 0.05–2.0 wt%, the mass concentration of polyaminopropyl biguanide is 0.1–3.0 wt%, and the mass concentration of polar solvent is 70–90 wt%.

20. The method for preparing a high-desalination polyamide reverse osmosis membrane according to any one of claims 1 to 7, characterized in that, In step four, the glycerol solution has a mass concentration of 5-10 wt%, and the post-soaking treatment time is 30-180 s.

21. The use of the high-desalination polyamide reverse osmosis membrane prepared by the method according to any one of claims 1 to 20 in a water treatment device and / or water treatment method.

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