Polyamide reverse osmosis separation membrane including antifouling layer and method for manufacturing same

Abstract

The present invention relates to a polyamide reverse osmosis separation membrane including an antifouling layer and a method for manufacturing same. More specifically, the present invention relates to a polyamide reverse osmosis separation membrane including an antifouling layer and a method for manufacturing same, the polyamide reverse osmosis separation membrane comprising: a porous support; a porous polymer support layer formed on at least one surface of the porous support; a polyamide layer formed on the polymer support layer; and an antifouling layer formed on the polyamide layer, wherein the antifouling layer comprises a heterocyclic amine, an aliphatic diamine, or a combination thereof. The polyamide reverse osmosis separation membrane according to the present invention can improve salt rejection and antifouling properties while having an excellent permeation flow rate.

Description

Polyamide reverse osmosis membrane including an internal fouling layer and method for manufacturing the same

[0001] The present invention relates to a polyamide reverse osmosis membrane including a fouling-resistant layer and a method for producing the same. More specifically, the present invention relates to a polyamide reverse osmosis membrane including a fouling-resistant layer, the membrane including a porous support, a porous polymer support layer formed on at least one surface of the porous support, a polyamide layer formed on the polymer support layer, and a fouling-resistant layer formed on the polyamide layer, wherein the fouling-resistant layer comprises a heterocyclic amine, an aliphatic diamine, or a combination thereof, and a method for producing the same. The polyamide reverse osmosis membrane according to the present invention can have excellent permeation flux while improving salt rejection and fouling resistance.

[0002]

[0003] Osmosis is the phenomenon in which a solvent moves through a semipermeable membrane from a solution with a low solute concentration to a solution with a high solute concentration. The pressure exerted on the solution with a high solute concentration due to the movement of the solvent is called osmotic pressure. However, if an external pressure higher than the osmotic pressure is applied conversely, the solvent will move toward the solution with a low solute concentration. This phenomenon is called reverse osmosis.

[0004] Traditionally, reverse osmosis membranes have been used to desalinate brackish or seawater, providing large quantities of fresh or purified water suitable for industrial, agricultural, or domestic use. Desalination of brackish or seawater using reverse osmosis membranes literally filters salts and other dissolved ions or molecules from the brine. By pressurizing the brine through a reverse osmosis membrane, purified water passes through the membrane, while the salts and other dissolved ions or molecules are blocked.

[0005] The performance of the membrane used in the membrane filtration process continuously decreases due to phenomena such as organic fouling, inorganic fouling, particular fouling, and bio-fouling depending on its use. Therefore, research on a reverse osmosis membrane that has excellent flux and salt rejection rate as well as excellent fouling resistance is necessary.

[0006] For example, Korean Patent No. 10-1230843 relates to a reverse osmosis membrane, characterized by comprising a porous support layer, a polyamide layer, and a coating layer further enhancing fouling resistance formed on the polyamide layer. However, although fouling resistance was improved, the invention suffered from a problem of reduced flow rate.

[0007]

[0008] Prior art literature

[0009] Republic of Korea Patent No. 10-1230843 (February 1, 2013)

[0010]

[0011] The present invention was devised to solve the above problems, and it was confirmed that a reverse osmosis membrane having improved salt rejection rate and fouling resistance while increasing permeation flow can be manufactured when an anti-fouling layer including a heterocyclic amine, an aliphatic diamine, or a combination thereof is formed on a polyamide layer, and the present invention was completed after confirming that the reverse osmosis membrane having improved salt rejection rate and fouling resistance can be manufactured.

[0012]

[0013] Accordingly, the present invention aims to provide a polyamide reverse osmosis membrane including an internal fouling layer.

[0014] In addition, the present invention aims to provide a method for manufacturing a polyamide reverse osmosis membrane including an internal fouling layer.

[0015]

[0016] Accordingly, the present invention discloses a polyamide reverse osmosis membrane including an internal fouling layer and a method for manufacturing the same.

[0017]

[0018] According to the first implementation example,

[0019] porous support;

[0020] A porous polymer support layer formed on at least one surface of the porous support;

[0021] A polyamide layer formed on the polymer support layer; and

[0022] Including an anti-fouling layer formed on the polyamide layer,

[0023] A polyamide reverse osmosis membrane including an anti-fouling layer is disclosed, wherein the anti-fouling layer comprises a heterocyclic amine, an aliphatic diamine or a combination thereof.

[0024] In the present invention, the heterocyclic amine may be selected from the group consisting of imidazole, pyridine, morpholine, and bipyridine.

[0025] In the present invention, the heterocyclic amine may be included in an amount of 0.02 to 0.2 wt% based on the total weight of the inner contamination layer.

[0026] In the present invention, the aliphatic diamine may be selected from the group consisting of 1,2-bis(2-aminoethoxy)ethane and 1,3-bis(2-aminopropoxy)propane.

[0027] In the present invention, the aliphatic diamine may be included in an amount of 0.001 to 0.1 wt% based on the total weight of the anti-fouling layer.

[0028] In the present invention, when the polyamide reverse osmosis membrane is operated for 1 hour under conditions of an aqueous solution containing 2,000 ppm of sodium chloride (NaCl), at a temperature of 25°C and a pressure of 225 psi, the flux may be 26 gfd or more and the rejection rate may be 99.4% or more.

[0029] In the present invention, when the polyamide reverse osmosis membrane is contaminated by adding 50 ppm of dry milk, which is an organic pollutant, to raw water containing 2,000 ppm of sodium chloride (NaCl) and circulating the raw water under a pressure of 225 psi for 2 hours, and then measuring the flow rate, the rate of decrease in the flow rate compared to the initial flow rate may be less than 10%.

[0030]

[0031] According to the second implementation example,

[0032] Step 1: Forming a porous polymer support layer by applying and drying a polymer solution on the surface of a porous support;

[0033] Step 2: forming a polyamide layer on the surface of the polymer support layer; and

[0034] It includes three steps of forming an anti-contamination layer on the surface of the polyamide layer,

[0035] A method for manufacturing a polyamide reverse osmosis membrane is disclosed, wherein the above-mentioned fouling layer comprises a heterocyclic amine, an aliphatic diamine, or a combination thereof.

[0036] In the present invention, the heterocyclic amine may be selected from the group consisting of imidazole, pyridine, morpholine, and bipyridine, and may be included in an amount of 0.02 to 0.2 wt% based on the total weight of the anti-fouling layer.

[0037] In the present invention, the aliphatic diamine may be selected from the group consisting of 1,2-bis(2-aminoethoxy)ethane and 1,3-bis(2-aminopropoxy)propane, and may be included in an amount of 0.001 to 0.1 wt% based on the total weight of the anti-fouling layer.

[0038] In the present invention, the amine group in the inner contamination layer can bind to unreacted -COCl of the polyamide layer.

[0039] In the present invention, when the polyamide reverse osmosis membrane is operated for 1 hour under an aqueous solution condition containing 2,000 ppm of sodium chloride (NaCl) at a temperature of 25°C and a pressure of 225 psi, the flux is 26 gfd or more and the rejection rate is 99.4% or more, and when 50 ppm of dry milk, which is an organic pollutant, is further added to raw water containing 2,000 ppm of sodium chloride (NaCl) and the raw water is circulated under a pressure of 225 psi for 2 hours to foul the membrane and then the flux is measured, the ratio of the flux reduced compared to the initial flux may be less than 10%.

[0040]

[0041] The polyamide reverse osmosis membrane according to the present invention forms an anti-fouling layer containing a heterocyclic amine, an aliphatic diamine, or a combination thereof on a polyamide layer, so that when operated for 1 hour under an aqueous solution condition containing 2,000 ppm of sodium chloride (NaCl) at a temperature of 25°C and a pressure of 225 psi, the flux is 26 gfd or more and the rejection rate is 99.4% or more, and when 50 ppm of dry milk, which is an organic pollutant, is further added to raw water containing 2,000 ppm of sodium chloride (NaCl) and the raw water is circulated under a pressure of 225 psi for 2 hours to foul the membrane and then the flux is measured, it was confirmed that the ratio of the flux reduced compared to the initial flux is less than 10% (see Experimental Example 1). Accordingly, it was proven that the polyamide reverse osmosis membrane according to the present invention can have excellent permeation flux while significantly improving salt rejection and fouling resistance by including an anti-fouling layer including a heterocyclic amine, an aliphatic diamine, or a combination thereof on a polyamide layer.

[0042]

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0044] Additionally, throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless specifically stated otherwise.

[0045]

[0046] 1. Polyamide reverse osmosis membrane containing an internal fouling layer

[0047] The present invention

[0048] porous support;

[0049] A porous polymer support layer formed on at least one surface of the porous support;

[0050] A polyamide layer formed on the polymer support layer; and

[0051] Including an anti-fouling layer formed on the polyamide layer,

[0052] The present invention aims to provide a polyamide reverse osmosis membrane including an anti-fouling layer, wherein the anti-fouling layer comprises a heterocyclic amine, an aliphatic diamine, or a combination thereof.

[0053] According to the present invention, when the polyamide reverse osmosis membrane is operated for 1 hour under conditions of an aqueous solution containing 2,000 ppm of sodium chloride (NaCl), at a temperature of 25°C and a pressure of 225 psi, the flux can be 26 gfd or more and the rejection rate can be 99.4% or more.

[0054] According to the present invention, when the polyamide reverse osmosis membrane is contaminated by adding 50 ppm of dry milk, which is an organic pollutant, to raw water containing 2,000 ppm of sodium chloride (NaCl) and circulating the raw water under a pressure of 225 psi for 2 hours, and then measuring the flow rate, the rate of decrease in the flow rate compared to the initial flow rate may be less than 10%.

[0055]

[0056] (1) Porous support

[0057] According to the present invention, the porous support is a typical microporous support, and is not particularly limited thereto, but the pore size should be sufficient to allow permeation of water while not being so large as to interfere with the formation of a thin film on the porous support.

[0058] According to the present invention, the pore size of the porous support may be 1 to 500 nm. If the pore size of the porous support exceeds 500 nm, the ultra-thin film may sink into the pores, and thus the desired flat sheet structure may not be formed.

[0059] According to the present invention, the average thickness of the porous support may be 30 to 300 μm, preferably 50 to 200 μm, but is not limited thereto.

[0060] According to the present invention, the porous support may include synthetic fibers or natural fibers. For example, the synthetic fibers may include one or more selected from polyester fibers, polypropylene fibers, nylon fibers, and polyethylene fibers, and the natural fibers may include cellulose fibers.

[0061]

[0062] (2) Porous polymer support layer

[0063] According to the present invention, the porous polymer support layer may include at least one selected from a polysulfone polymer, a polyethersulfone polymer, a polyamide polymer, a polyimide polymer, a polyester polymer, an olefin polymer, polyvinylidene fluoride, and polyacrylonitrile.

[0064]

[0065] (3) Polyamide layer

[0066] According to the present invention, the polyamide layer can be formed by interfacial polymerization of a polyfunctional amine and a polyfunctional acyl halide.

[0067] According to the present invention, the polyfunctional amine may include, but is not limited to, m-phenylenediamine, p-phenylenediamine, 1,3,6-benzenetriamine, 4-chloro-1,3-phenylenediamine, 6-chloro-1,3-phenylenediamine, 3-chloro-1,4-phenylenediamine, or a combination thereof.

[0068] According to the present invention, the polyfunctional acyl halide may include, but is not limited to, trimesoyl chloride (TMC), isophthaloyl chloride (IPC), terephthaloyl chloride (TPC), or a combination thereof.

[0069]

[0070] (4) My contaminated layer

[0071] According to the present invention, the inner contamination layer may include a heterocyclic amine, an aliphatic diamine, or a combination thereof.

[0072] According to the present invention, the heterocyclic amine may be selected from the group consisting of imidazole, pyridine, morpholine, and bipyridine.

[0073] According to the present invention, the heterocyclic amine may be included in an amount of 0.02 to 0.2 wt% based on the total weight of the inner contamination layer.

[0074] According to the present invention, the aliphatic diamine may be selected from the group consisting of 1,2-bis(2-aminoethoxy)ethane and 1,3-bis(2-aminopropoxy)propane.

[0075] According to the present invention, the aliphatic diamine may be included in an amount of 0.001 to 0.1 wt% based on the total weight of the anti-fouling layer.

[0076]

[0077] 2. Method for manufacturing a polyamide reverse osmosis membrane including an internal fouling layer

[0078] The present invention

[0079] Step 1: Forming a porous polymer support layer by applying and drying a polymer solution on the surface of a porous support;

[0080] Step 2: forming a polyamide layer on the surface of the polymer support layer; and

[0081] It includes three steps of forming an anti-contamination layer on the surface of the polyamide layer,

[0082] The above-mentioned inner fouling layer is intended to provide a method for manufacturing a polyamide reverse osmosis membrane, wherein the inner fouling layer comprises a heterocyclic amine, an aliphatic diamine or a combination thereof.

[0083]

[0084] (1) Step 1

[0085] According to the present invention, the porous support may include synthetic fibers or natural fibers. For example, the synthetic fibers may include one or more selected from polyester fibers, polypropylene fibers, nylon fibers, and polyethylene fibers, and the natural fibers may include cellulose fibers. The average thickness of the porous support may be 30 to 300 μm, preferably 50 to 200 μm, but is not limited thereto.

[0086] According to the present invention, the polymer solution may include a polymer compound and a residual solvent, and the polymer compound may be included in an amount of 5 to 40 wt%, and preferably 7 to 35 wt%, of the total weight of the polymer solution. The polymer compound may include at least one selected from a polysulfone polymer, a polyethersulfone polymer, a polyamide polymer, a polyimide polymer, a polyester polymer, an olefin polymer, polyvinylidene fluoride, and polyacrylonitrile. The solvent included in the polymer solution may be used without particular limitation as long as it can completely and uniformly dissolve the polymer without precipitation, and may include, for example, at least one selected from N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and dimethylacetamide (DMAc).

[0087] According to the present invention, the coating may be performed so that the thickness of the polymer support layer is 30 to 300 μm. If the thickness of the polymer support layer is less than 30 μm, problems with reduced flow rate and durability due to compaction may occur, and if it exceeds 300 μm, problems with reduced flow rate may occur as the flow path becomes longer.

[0088]

[0089] (2) Step 2

[0090] According to the present invention, the polyamide layer can be formed by sequentially coating a polyfunctional amine solution and a polyfunctional acyl halide solution on the porous support. The coating of the polyfunctional amine solution can be performed by spraying or immersing the polyfunctional amine solution on the porous support on which the polymer support layer is formed, and can be performed for 0.1 to 10 minutes. The polyfunctional amine can include, but is not limited to, m-phenylenediamine, p-phenylenediamine, 1,3,6-benzenetriamine, 4-chloro-1,3-phenylenediamine, 6-chloro-1,3-phenylenediamine, 3-chloro-1,4-phenylenediamine, or a combination thereof. The polyfunctional acyl halide solution can be dry-treated for 5 seconds to 3 minutes. The above polyfunctional acyl halide may include, but is not limited to, trimesoyl chloride (TMC), isophthaloyl chloride (IPC), terephthaloyl chloride (TPC), or a combination thereof.

[0091] According to the present invention, the polyamide layer may have a thickness of 0.1 to 1.0 μm. If the thickness of the polyamide layer exceeds 1.0 μm, the thickness of the selective layer may become excessively thick, which may cause a problem of reduced flow rate.

[0092] (3) Step 3

[0093] According to the present invention, the fouling-resistant layer may include a heterocyclic amine, an aliphatic diamine, or a combination thereof. The heterocyclic amine may be selected from the group consisting of imidazole, pyridine, morpholine, and bipyridine, and may be included in an amount of 0.02 to 0.2 wt% based on the total weight of the fouling-resistant layer. The aliphatic diamine may be selected from the group consisting of 1,2-bis(2-aminoethoxy)ethane and 1,3-bis(2-aminopropoxy)propane, and may be included in an amount of 0.001 to 0.1 wt% based on the total weight of the fouling-resistant layer.

[0094] According to the present invention, the amine group in the inner contamination layer can be combined with unreacted -COCl of the polyamide layer.

[0095]

[0096] Hereinafter, the present invention will be described in detail through examples. However, the following examples and experimental examples are merely illustrative of one form of the present invention, and the scope of the present invention is not limited by the following examples and experimental examples.

[0097]

[0098] <Example>

[0099] Comparative Example 1. Manufacturing of a reverse osmosis membrane without a fouling layer

[0100] A 140 ㎛ thick porous polysulfone support cast on a nonwoven fabric with an average thickness of 100 ㎛ was immersed in an amine aqueous solution containing 2.0 wt % of metaphenylenediamine (MPD), a polyfunctional amine, and 0.2 wt % of ethylhexanediol as an additive for 40 seconds, and then the excess aqueous solution was removed. The support with the amine aqueous solution applied to the surface was immersed in an organic solution containing 0.1 wt % of trimesoyl chloride (TMC), a polyfunctional acid halide compound, and Isopar solvent as a solvent for 1 minute to carry out interfacial polymerization. Then, excess organic solution was removed by spraying air at 0.5 bar for 10 seconds, and a polyamide coating layer was formed on the surface of the support by drying at 25°C for 1.5 minutes, and thermal crosslinking was performed at 60°C for 2 minutes.

[0101]

[0102] Example 1. Preparation of reverse osmosis membrane containing imidazole fouling layer

[0103] The polyamide thin film surface manufactured in Comparative Example 1 was sprayed with an aqueous solution containing 0.05 wt% imidazole for 20 seconds, the excess solution was removed, and then dried at 50°C for 4 minutes. The membrane was then stored in air at room temperature for 1 day to manufacture a final polyamide reverse osmosis membrane.

[0104]

[0105] Example 2. Preparation of reverse osmosis membrane containing imidazole and aliphatic diamine fouling layer

[0106] A polyamide reverse osmosis membrane was manufactured using the same method as in Example 1, except that 0.05 wt% imidazole and 0.02 wt% aliphatic diamine (1,2-bis(2-aminoethoxy)ethane) were used instead of 0.05 wt% imidazole in Example 1.

[0107]

[0108] Comparative Example 2. Preparation of a reverse osmosis membrane containing a methylamine-containing fouling layer.

[0109] A polyamide reverse osmosis membrane was manufactured using the same method as in Example 1, except that methylamine was used instead of imidazole in Example 1.

[0110]

[0111] Comparative Example 3. Manufacturing of a reverse osmosis membrane including a glycine-containing fouling layer.

[0112] A polyamide reverse osmosis membrane was manufactured using the same method as in Example 1, except that glycine was used instead of imidazole in Example 1.

[0113]

[0114] Comparative Example 4. Manufacturing of a reverse osmosis membrane containing an ethanolamine-containing fouling layer.

[0115] A polyamide reverse osmosis membrane was manufactured using the same method as Example 1, except that ethanolamine was used instead of imidazole in Example 1.

[0116]

[0117] <Experimental Example>

[0118] Experimental Example 1. Evaluation of flow rate and salt rejection rate

[0119] The reverse osmosis membranes manufactured according to the above examples and comparative examples were measured for permeation flux and salt rejection rate at 25°C and 225 psi in a 2,000 ppm sodium chloride (NaCl) aqueous solution. In addition, the reverse osmosis membranes manufactured according to the above examples and comparative examples were measured for flux reduction rate compared to the initial performance after 2 hours of operation in raw water containing 50 ppm dry milk.

[0120] No. Flow rate (gfd) Removal rate (%) Flow rate reduction rate (%) Comparative example 125.7498.87-15.7 Exemplary example 128.0999.43-8.64 Exemplary example 227.6699.64-8.29 Comparative example 226.8899.05-13.95 Comparative example 326.2299.35-15.08 Comparative example 424.9199.02-9.96

[0121] As a result, as can be seen from Table 1 above, the flow rate, removal rate, and flow rate reduction rate of Examples 1 and 2 according to the present invention were found to be significantly improved compared to Comparative Examples 1 to 4. Specifically, the flow rates of the reverse osmosis membranes according to Comparative Example 1 without a fouling layer, Comparative Example 2 with a methylamine fouling layer, Comparative Example 3 with a glycine fouling layer, and Comparative Example 3 with an ethanolamine fouling layer were 25.74, 26.88, 26.22, and 24.91, respectively, whereas the flow rates of the reverse osmosis membranes according to Examples 1 and 2 were confirmed to be 28.09 and 27.66, which were increased compared to the Comparative Example. In addition, the flow rate reduction rates of Comparative Examples 1 to 4 were -15.7%, -13.95%, -15.08%, and -9.96%, respectively, while the flow rate reduction rates of the reverse osmosis membranes according to Examples 1 and 2 were -8.64 and -8.29, respectively, confirming that they had significantly improved fouling resistance compared to the Comparative Examples.

[0122] While specific aspects of the present invention have been described in detail above, it should be apparent to those skilled in the art that these specific descriptions are merely preferred implementation examples and are not intended to limit the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents.

[0123]

[0124] The present invention can provide a polyamide reverse osmosis membrane having excellent permeation rate and significantly improved salt rejection rate and fouling resistance by including an anti-fouling layer comprising a heterocyclic amine, an aliphatic diamine, or a combination thereof on a polyamide layer.

Claims

1. Porous support; A porous polymer support layer formed on at least one surface of the porous support; A polyamide layer formed on the polymer support layer; and Including an anti-fouling layer formed on the polyamide layer, A polyamide reverse osmosis membrane including an anti-fouling layer, wherein the anti-fouling layer comprises a heterocyclic amine, an aliphatic diamine or a combination thereof.

2. In paragraph 1, A polyamide reverse osmosis membrane including an anti-fouling layer, characterized in that the heterocyclic amine is selected from the group consisting of imidazole, pyridine, morpholine, and bipyridine.

3. In paragraph 1, A polyamide reverse osmosis membrane including an anti-fouling layer, characterized in that the heterocyclic amine is included in an amount of 0.02 to 0.2 wt% based on the total weight of the anti-fouling layer.

4. In paragraph 1, A polyamide reverse osmosis membrane including an anti-fouling layer, characterized in that the above aliphatic diamine is selected from the group consisting of 1,2-bis(2-aminoethoxy)ethane and 1,3-bis(2-aminopropoxy)propane.

5. In paragraph 1, A polyamide reverse osmosis membrane including a fouling-resistant layer, characterized in that the above-mentioned aliphatic diamine is included in an amount of 0.001 to 0.1 wt% based on the total weight of the fouling-resistant layer.

6. In paragraph 1, A polyamide reverse osmosis membrane including an anti-fouling layer, characterized in that when the polyamide reverse osmosis membrane is operated for 1 hour under conditions of an aqueous solution containing 2,000 ppm of sodium chloride (NaCl), at a temperature of 25°C and a pressure of 225 psi, the flux is 26 gfd or more and the removal rate is 99.4% or more.

7. In paragraph 1, The polyamide reverse osmosis membrane is characterized in that, when the membrane is contaminated by adding 50 ppm of dry milk, which is an organic pollutant, to raw water containing 2,000 ppm of sodium chloride (NaCl) and circulating the raw water under a pressure of 225 psi for 2 hours, and then measuring the flow rate, the ratio of the flow rate decreased compared to the initial flow rate is less than 10%, including a fouling-resistant layer.

8. Step 1: Forming a porous polymer support layer by applying and drying a polymer solution on the surface of a porous support; Step 2: forming a polyamide layer on the surface of the polymer support layer; and It includes three steps of forming an anti-contamination layer on the surface of the polyamide layer, A method for manufacturing a polyamide reverse osmosis membrane, wherein the above-mentioned fouling layer comprises a heterocyclic amine, an aliphatic diamine or a combination thereof.

9. In paragraph 8, A method for manufacturing a polyamide reverse osmosis membrane, wherein the heterocyclic amine may be selected from the group consisting of imidazole, pyridine, morpholine, and bipyridine, and is included in an amount of 0.02 to 0.2 wt% based on the total weight of the fouling layer.

10. In paragraph 8, A method for manufacturing a polyamide reverse osmosis membrane, characterized in that the above aliphatic diamine may be selected from the group consisting of 1,2-bis(2-aminoethoxy)ethane and 1,3-bis(2-aminopropoxy)propane, and is included in an amount of 0.001 to 0.1 wt% with respect to the total weight of the fouling-resistant layer.

11. In paragraph 8, A method for manufacturing a polyamide reverse osmosis membrane, characterized in that the amine group in the above-mentioned inner layer combines with unreacted -COCl of the polyamide layer.

12. In paragraph 8, A method for manufacturing a polyamide reverse osmosis membrane, wherein the polyamide reverse osmosis membrane is operated for 1 hour under an aqueous solution condition containing 2,000 ppm of sodium chloride (NaCl) at a temperature of 25°C and a pressure of 225 psi, and has a flux of 26 gfd or more and a rejection rate of 99.4% or more, and when 50 ppm of dry milk, which is an organic pollutant, is further added to raw water containing 2,000 ppm of sodium chloride (NaCl), the raw water is circulated under a pressure of 225 psi for 2 hours to foul the membrane, and then the flux is measured, the ratio of the flux reduced compared to the initial flux is less than 10%.