Method for producing separation membrane for water treatment

Abstract

The present specification relates to a method for producing a water-treatment separation membrane, which is characterized by comprising a step for forming a polyamide active layer by coating a porous layer with an aqueous amine solution and an acid halide organic solution, and a step for washing the polyamide active layer with a pre-rinse solution, and the pre-rinse solution contains a specific type of nitrogen-containing heterocyclic compound.

Description

Technical Field

[0001] This specification relates to a method for manufacturing a water treatment separation membrane.

[0002] This specification claims the priority of Korean Patent Application No. 10-2024-0005012, filed with the Korean Patent Office on January 11, 2024, the entire contents of which are incorporated herein by reference. Background Art

[0003] Liquid separation is classified into microfiltration, ultrafiltration, nanofiltration, reverse osmosis, precipitation, active transport, and electrodialysis, etc., according to the pores of the membrane. Among them, the reverse osmosis method refers to a process of desalination using a semipermeable membrane that allows water to pass through but is impermeable to salts. When high-pressure water containing dissolved salts is introduced to one side of the semipermeable membrane, purified water from which salts have been removed flows to the other side at a lower pressure.

[0004] Specifically, as a representative example of such a water treatment separation membrane, a reverse osmosis membrane or a nanofiltration membrane can be cited, and research on improving the salt rejection rate or permeation flux is ongoing.

[0005] The reverse osmosis membrane / nanofiltration membrane is composed of a support layer on a non-woven fabric, an active layer of polyamide, and a protective layer on the surface of the active layer, and can separate solvents and solutes using the reverse osmosis phenomenon. The permeation flux and ion rejection rate of the reverse osmosis membrane / nanofiltration membrane are used as important indicators for showing the performance of the membrane, and such performance is greatly affected by the polyamide active layer formed by the interfacial polymerization of an aqueous solution and an organic solution containing each monomer.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] (Patent Document 1) Korean Patent Publication No. 10-2015-0016475 Summary of the Invention

[0009] Technical Problem

[0010] This specification provides a method for manufacturing a water treatment separation membrane that provides excellent salt rejection rate and effectively improves the permeation flux at the same time.

[0011] Solution to the Problem

[0012] One embodiment of the present specification relates to a method for manufacturing a water treatment separation membrane, including: a step of forming a polyamide active layer by coating an amine aqueous solution and an acyl halide organic solution on a porous layer; and a step of washing the polyamide active layer with a pre-rinse solution, wherein the pre-rinse solution contains a nitrogen-containing heterocyclic compound, and the nitrogen-containing heterocyclic compound is (di)alkylaminopyridine, alkylimidazole or alkyltriazole.

[0013] Advantages of the Invention

[0014] The method for manufacturing a water treatment separation membrane according to one embodiment of the present specification can minimize the reduction of the salt rejection rate and effectively improve the permeation flux. Specifically, it was confirmed that the flux performance of the separation membrane was improved by using the above pre-rinse solution in the pre-rinse step after forming the polyamide active layer.

[0015] After forming the polyamide active layer, when using the pre-rinse solution of the present invention in the pre-rinse step for washing away reaction residues, the specific nitrogen-containing heterocyclic compound contained therein forms hydrogen bonds with unreacted monomers and polyamide chains, making the residues easily dissolved, and improving the permeation flux by increasing the free volume.

[0016] Meanwhile, by including an amine compound and an amine-based additive in the amine aqueous solution, the permeation flux is further improved. This is related to the above pre-rinse process. The higher the residual amount of amine groups, the more hydrogen bonds are formed between the nitrogen-containing heterocyclic compound and the unreacted amine, thus having the effect of activating the increase in free volume. Therefore, by further including an amine-based additive, the residual amount of amine groups is increased, maximizing the flux improvement effect. Brief Description of the Drawings

[0017] Figure 1 Illustrated is a water treatment separation membrane according to one embodiment of the present specification.

[0018] Description of Reference Numerals

[0019] 100: First porous support

[0020] 200: Second porous support

[0021] 300: Polyamide active layer

[0022] 400: Brine

[0023] 500: Purified water

[0024] 600: Concentrated water Detailed Description of the Embodiment

[0025] Next, this specification will be described in more detail.

[0026] In this specification, when it is stated that a certain member is "on" another member, it includes not only the case where a certain member is in contact with another member, but also the case where there are other members between the two members.

[0027] In this specification, when it is stated that a certain part "includes" a certain constituent element, unless there is a particularly contrary record, it means that other constituent elements can be further included, rather than excluding other constituent elements.

[0028] In this specification, "A to B" means A or more and B or less.

[0029] According to a manufacturing method of a water treatment separation membrane according to an embodiment of this specification, it includes: a step of forming a polyamide active layer by coating an amine aqueous solution and an acyl halide organic solution on a porous layer; and a step of washing the above polyamide active layer with a pre-rinse solution, the above pre-rinse solution contains a nitrogen-containing heterocyclic compound, and the above nitrogen-containing heterocyclic compound is (di)alkylaminopyridine, alkylimidazole or alkyltriazole.

[0030] In an embodiment of this specification, the above porous layer can be an ultrafiltration layer (Ultrafiltration, UF).

[0031] In an embodiment of this specification, the manufacturing method of the above water treatment separation membrane may further include a step of providing a porous layer.

[0032] In an embodiment of this specification, the step of providing the above porous layer includes a step of preparing a first porous support; and a step of forming a second porous support by coating a composition for forming the second porous support on the above first porous support.

[0033] In an embodiment of this specification, as the above first porous support, non-woven fabric can be used. As the material of the above non-woven fabric, polyethylene terephthalate can be used, but it is not limited thereto.

[0034] The thickness of the above first porous support can be 50 μm to 150 μm, but it is not limited thereto. Preferably, the above thickness can be 80 μm to 120 μm. When the thickness of the above first porous support satisfies the above range, the durability of the water treatment separation membrane can be maintained.

[0035] In one embodiment of the present specification, the composition for forming the second porous support may include a polymer material. As the polymer material, for example, one or more selected from polysulfone, polyethersulfone, polycarbonate, polyethylene oxide, polyimide, polyetherimide, polyetheretherketone, polypropylene, polymethylpentene, polymethyl chloride, polyvinylidene fluoride, and mixtures thereof may be used, but it is not necessarily limited thereto. Specifically, polysulfone may be used as the polymer material.

[0036] In one embodiment of the present specification, based on 100 parts by weight of the entire composition for forming the second porous support, 10 to 20 parts by weight of the polysulfone may be included. The remaining components in the composition for forming the second porous support other than polysulfone may be a solvent, and the solvent may be dimethylformamide (DMF), but it is not limited thereto, and a solvent used in the technical field may be appropriately employed.

[0037] When the polysulfone is included in the composition for forming the second porous support in the above weight part range, when forming the second porous support with the composition for forming the second porous support, a second porous support with a target thickness can be formed.

[0038] The thickness of the second porous support may be 30 μm to 70 μm, but it is not limited thereto. Preferably, the thickness may be 30 μm to 60 μm, or 30 μm to 50 μm. When the thickness of the second porous support satisfies the above range, the durability of the water treatment separation membrane including the porous layer containing the second porous support can be appropriately maintained.

[0039] The composition for forming the second porous support may be a homogeneous liquid obtained by adding polysulfone solid to dimethylformamide as a solvent and dissolving it at 80 °C to 85 °C for 12 hours.

[0040] In one embodiment of the present specification, the overall thickness of the porous layer may be 70 μm to 250 μm.

[0041] In another embodiment of the present specification, the step of providing the porous layer includes purchasing a commercially available porous layer and using it.

[0042] Except for the manufacturing method, the specific description of the commercially available porous layer is the same as the above description.

[0043] In one embodiment of the present specification, the porous layer includes a first porous support and a second porous support, and the step of forming the polyamide active layer may include the step of coating an aqueous amine solution and an organic acyl halide solution on the second porous support.

[0044] In one embodiment of the present specification, the step of coating an aqueous amine solution and an organic acyl halide solution on the porous layer may be the step of coating the aqueous amine solution on the porous layer and then coating the organic acyl halide solution.

[0045] In one embodiment of the present specification, the step of forming the polyamide active layer may include the step of coating an aqueous amine solution on the porous layer to form an aqueous solution layer; and the step of coating an organic acyl halide solution on the aqueous solution layer.

[0046] In one embodiment of the present specification, the step of forming the polyamide active layer may include the step of coating an aqueous amine solution on the second porous support to form an aqueous solution layer; and the step of coating an organic acyl halide solution on the aqueous solution layer.

[0047] In one embodiment of the present specification, the aqueous amine solution may contain an amine compound and a solvent.

[0048] In one embodiment of the present specification, the amine compound is not particularly limited, and as long as it is a compound applicable in the technical field, it can be appropriately adopted. For example, the amine compound may be one or a mixture of two or more selected from m-phenylenediamine, p-phenylenediamine, 1,2,4-benzenetriamine, 1,3,6-benzenetriamine (TAB), 4-chloro-1,3-phenylenediamine, 6-chloro-1,3-phenylenediamine, 2-chloro-1,4-phenylenediamine, and 3-chloro-1,4-phenylenediamine. Specifically, m-phenylenediamine (mPD) is preferably used.

[0049] In one embodiment of the present specification, based on 100 parts by weight of the total aqueous amine solution, the amine compound may be contained in an amount of 1 part by weight to 15 parts by weight, preferably, it may be contained in an amount of 1 part by weight to 10 parts by weight, and more preferably, it may be contained in an amount of 3 parts by weight to 10 parts by weight.

[0050] When the content of the amine compound satisfies the above range, when forming the polyamide active layer included in the water treatment separation membrane, the amine compound can be stably dissolved in the aqueous solution, and the reaction with the organic acyl halide solution can proceed smoothly.

[0051] In one embodiment of the present specification, the solvent may be water, but it is not limited thereto, and any solvent that can dissolve the composition contained in the aqueous amine solution can be used.

[0052] In one embodiment of the present specification, the above solvent may be the remaining components in the above aqueous amine solution other than the above amine compound.

[0053] In one embodiment of the present specification, the above aqueous amine solution may further contain an amine-based additive.

[0054] The above amine-based additive is different from the above amine compound.

[0055] By further containing the above amine-based additive in the above aqueous amine solution, a relatively large amount of unreacted amino groups remain after the formation of the polyamide active layer. Thus, in the above pre-rinse step, a hydrogen bond is formed between the nitrogen-containing heterocyclic compound and the unreacted amino groups, thereby activating the process of increasing free volume.

[0056] In one embodiment of the present specification, the above amine-based additive is not limited as long as it contains an amino group, but may not include the compound used as the above amine compound.

[0057] In one embodiment of the present specification, the above amine-based additive may contain a hydroxyl group.

[0058] In one embodiment of the present specification, the above amine-based additive may include one or more selected from aminophenol, amino alcohol, and aminobenzoic acid.

[0059] In one embodiment of the present specification, the above amine-based additive may include aminophenol, amino alcohol, and aminobenzoic acid.

[0060] In one embodiment of the present specification, the above amine-based additive may contain a phenol structure.

[0061] In one embodiment of the present specification, the above amine-based additive may include aminophenol.

[0062] In one embodiment of the present specification, based on 100 parts by weight of the whole above aqueous amine solution, the above amine-based additive may be contained in an amount of 0.01 part by weight to 0.2 part by weight. Preferably, it may be contained in an amount of 0.02 part by weight to 0.18 part by weight. More preferably, it may be contained in an amount of 0.03 part by weight to 0.15 part by weight.

[0063] When the content of the above amine-based additive satisfies the above range, while participating in the formation of the polyamide active layer, it can react appropriately with the nitrogen-containing heterocyclic compound during the subsequent pre-rinse process, thereby contributing to an increase in the permeation flux.

[0064] In one embodiment of the present specification, the above aqueous amine solution may contain an amine compound, an amine-based additive, and a solvent.

[0065] In one embodiment of the present specification, the above solvent may be the remaining components in the above amine aqueous solution except for the above amine compound and amine-based additives.

[0066] In one embodiment of the present specification, the above amine aqueous solution may further contain a surfactant.

[0067] In one embodiment of the present specification, the above surfactant is an additive added to improve the wetting of the aqueous solution, and as long as it functions as a surfactant, its type is not limited.

[0068] By including a surfactant in the above amine aqueous solution, a uniform polyamide active layer can be formed.

[0069] In one embodiment of the present specification, the above surfactant may be an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant.

[0070] In one embodiment of the present specification, the above surfactant may include sodium lauryl sulfate (SLS); alkyl ether sulfates; alkyl sulfates; olefin sulfonates; alkyl ether carboxylates; sulfosuccinates; aromatic sulfonates; octylphenol ethoxylates; ethoxylated nonylphenols; alkyl poly(ethylene oxide); copolymers of poly(ethylene oxide) and poly(propylene oxide); alkyl polyglycosides such as octyl glucoside and decyl maltoside; fatty alcohols such as cetyl alcohol, oleyl alcohol alkyl hydroxyethyl dimethyl ammonium chloride, cetyl trimethyl ammonium bromide, cetyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium bromide, and hexadecyl trimethyl ammonium chloride; and one or more of alkyl betaines.

[0071] In one embodiment of the present specification, the above surfactant may be an anionic surfactant.

[0072] In one embodiment of the present specification, the above surfactant may be sodium lauryl sulfate (SLS).

[0073] When using sodium lauryl sulfate (SLS) as the above surfactant, sodium lauryl sulfate has a high degree of affinity for water and oil (Hydrophile-Lipophine Balance, HLB), is easily soluble in water, and since the Critical Michelle Comcentration (CMC) is also high, even if it is added in excess, it does not interfere with the formation of the polyamide active layer.

[0074] In one embodiment of the present specification, based on 100 parts by weight of the entire amine aqueous solution, 0.001 to 2 parts by weight of the above surfactant may be included. Preferably, 0.005 to 1.5 parts by weight may be included. More preferably, 0.01 to 1 part by weight may be included.

[0075] When the content of the surfactant in the amine aqueous solution satisfies the above range, the effects caused by the surfactant can be suitably exhibited.

[0076] When the content of the above surfactant is less than 0.001 part by weight, since the content is too low, the surfactant cannot function. When it is greater than 2 parts by weight, since the amount is too large, there is a problem that the active layer cannot be formed normally.

[0077] In one embodiment of the present specification, the above solvent may be the remaining components in the above amine aqueous solution other than the above amine compound, amine-based additive, and surfactant.

[0078] In one embodiment of the present specification, the above amine aqueous solution may further include one or more of a wetting agent and a swelling agent. As the above wetting agent and swelling agent, there is no limitation as long as it is used in the present technical field.

[0079] In one embodiment of the present specification, the above solvent may be the remaining components in the above amine aqueous solution other than the above amine compound, amine-based additive, surfactant, wetting agent, and swelling agent.

[0080] In one embodiment of the present specification, the method applicable to the above step of forming the aqueous solution layer is not particularly limited. As long as it is a method capable of forming an aqueous solution layer on the above porous layer, it can be used without limitation. Specifically, the method of coating the above amine aqueous solution on the above porous layer is not particularly limited, and a coating method known in the present technical field can be used.

[0081] In one embodiment of the present specification, after the step of forming the above aqueous solution layer, a step of removing the excess amine aqueous solution may further be included.

[0082] The method applicable in the above step of removing the excessive amine aqueous solution is not particularly limited, and a method applicable in the present technical field can be used. The aqueous solution layer formed on the above porous layer may be unevenly distributed when there is too much aqueous solution present on the porous layer. In the case of uneven distribution of the aqueous solution, an uneven active layer may be formed through subsequent interfacial polymerization. Therefore, it is preferred to remove the excessive aqueous solution after forming the aqueous solution layer on the above porous layer. The removal of the excessive aqueous solution is not particularly limited. For example, a sponge, an air knife, nitrogen blowing, natural drying, a compression roller, etc. can be used.

[0083] In one embodiment of the present specification, the above acyl halide organic solution contains an acyl halide compound and an organic solvent.

[0084] In one embodiment of the present specification, the above acyl halide compound is not particularly limited. For example, it can be an aromatic compound having 2 to 3 carboxylic acid halides.

[0085] In one embodiment of the present specification, the above acyl halide compound can be one or a mixture of two or more selected from trimesoyl chloride (TMC), isophthaloyl chloride, and terephthaloyl chloride.

[0086] In one embodiment of the present specification, the above acyl halide compound can be trimesoyl chloride (TMC).

[0087] In one embodiment of the present specification, based on 100 parts by weight of the whole above acyl halide organic solution, 0.1 part by weight to 0.5 part by weight of the above acyl halide compound can be included. When the content of the above acyl halide compound satisfies the above range, it has the effect of preventing the reduction of the salt rejection rate and permeation flux of the finally manufactured water treatment separation membrane.

[0088] In one embodiment of the present specification, as the above organic solvent, an aliphatic hydrocarbon solvent can be used. For example, Freons and hydrophobic liquids that are immiscible with water such as hexane, cyclohexane, heptane, and alkanes, such as alkanes having 5 to 12 carbon atoms and their mixtures, namely IsoPar (Exxon), ISOL-C (SK Chem), ISOL-G (Exxon), etc., but are not limited thereto.

[0089] In one embodiment of the present specification, the above organic solvent can be IsoPar G which is a paraffin-based solvent.

[0090] In one embodiment of the present specification, based on 100 parts by weight of the whole above acyl halide organic solution, 87.5 parts by weight to 99.9 parts by weight of the above organic solvent can be included.

[0091] In one embodiment of the present specification, based on 100 parts by weight of the entire acyl halide organic solution, 99.5 to 99.9 parts by weight of the above-mentioned organic solvent may be included.

[0092] When the content of the above-mentioned organic solvent satisfies the above range, it has the effect of preventing the reduction of the salt rejection rate and the permeation flux of the finally manufactured water treatment separation membrane.

[0093] In one embodiment of the present specification, the above-mentioned organic solvent may be the remaining components in the acyl halide organic solution except for the above-mentioned acyl halide compound.

[0094] In one embodiment of the present specification, the acyl halide organic solution may further contain an organic co-solvent.

[0095] In one embodiment of the present specification, the type of the above-mentioned organic co-solvent is not particularly limited, and a solvent used in the technical field may be used.

[0096] In one embodiment of the present specification, based on 100 parts by weight of the entire acyl halide organic solution, 0 to 10 parts by weight of the above-mentioned organic co-solvent may be included.

[0097] In one embodiment of the present specification, based on 100 parts by weight of the entire acyl halide organic solution, 87.5 to 99.5 parts by weight of the above-mentioned organic solvent may be included.

[0098] In one embodiment of the present specification, the method applicable in the step of coating the acyl halide organic solution is not particularly limited, and a coating method known in the technical field may be used.

[0099] In one embodiment of the present specification, in the step of coating the acyl halide organic solution, interfacial polymerization of the above-mentioned amine aqueous solution and the acyl halide organic solution may occur. Specifically, when the acyl halide organic solution is coated on the above-mentioned aqueous solution layer, the amine aqueous solution in the aqueous solution layer contacts the acyl halide organic solution, and interfacial polymerization occurs during the contact (simultaneously with the contact).

[0100] In one embodiment of the present specification, the step of coating the acyl halide organic solution on the above-mentioned aqueous solution layer may be a step of performing interfacial polymerization of the amine aqueous solution in the aqueous solution layer and the acyl halide organic solution.

[0101] Specifically, when the acyl halide organic solution is coated on the above-mentioned aqueous solution layer, the amine compound in the aqueous solution layer reacts with the acyl halide compound in the organic solution, and at the same time, polyamide is formed by interfacial polymerization, adsorbed on the porous layer to form a film, thereby forming a polyamide active layer.

[0102] In one embodiment of the present specification, the step of forming the polyamide active layer may further include the step of drying the polyamide active layer formed on the porous layer after coating the organic solution on the aqueous solution layer.

[0103] In one embodiment of the present specification, the drying method in the step of drying the polyamide active layer is not particularly limited, and a method applicable in the present technical field may be appropriately adopted. For example, the polyamide active layer may be dried in an oven at 90 °C for 3 minutes.

[0104] In one embodiment of the present specification, the thickness of the polyamide active layer may be 100 nm to 500 nm.

[0105] In one embodiment of the present specification, the thickness of the polyamide active layer may be 150 nm to 450 nm, or 200 nm to 400 nm.

[0106] When the thickness of the polyamide active layer satisfies the above range, the salt rejection rate and permeation flux of the water treatment separation membrane to be achieved in the present specification can be satisfied.

[0107] The method for manufacturing a water treatment separation membrane according to one embodiment of the present specification includes the step of washing the polyamide active layer with a pre-rinse solution.

[0108] In one embodiment of the present specification, the pre-rinse solution contains a nitrogen-containing heterocyclic compound, and the nitrogen-containing heterocyclic compound is (di)alkylaminopyridine, alkylimidazole or alkyltriazole.

[0109] During the process of washing the manufactured polyamide active layer with the pre-rinse solution, unreacted monomers and oligomers, i.e., residues that did not participate in the formation of the active layer, bind to the nitrogen-containing heterocyclic compound and are washed away from the polyamide active layer. By washing away the residues unnecessary for the manufacture of the separation membrane as described above, the performance of the separation membrane can be improved. In addition, the free volume increases, which helps to improve the flux.

[0110] In one embodiment of the present specification, the nitrogen-containing heterocyclic compound contains at least one carbon-nitrogen double bond.

[0111] That is, the nitrogen-containing heterocyclic compound must contain a nitrogen atom and an unsaturated bond.

[0112] In one embodiment of the present specification, the nitrogen-containing heterocyclic compound is composed of one or more bonds selected from single or double bonds between carbon and nitrogen, single or double bonds between carbon and carbon, single or double bonds between nitrogen and nitrogen, single bonds between carbon and hydrogen, and single bonds between nitrogen and hydrogen.

[0113] That is, the above nitrogen-containing heterocyclic compound does not contain a single bond or a double bond between carbon and oxygen, etc.

[0114] In one embodiment of the present specification, the above nitrogen-containing heterocyclic compound may include one or more selected from pyridine-based compounds, imidazole-based compounds, and triazole-based compounds.

[0115] In one embodiment of the present specification, the above nitrogen-containing heterocyclic compound may be a pyridine-based compound, an imidazole-based compound, or a triazole-based compound.

[0116] In one embodiment of the present specification, the above nitrogen-containing heterocyclic compound may be a pyridine-based compound or an imidazole-based compound.

[0117] In one embodiment of the present specification, the above nitrogen-containing heterocyclic compound may be a pyridine-based compound.

[0118] In the present specification, a pyridine-based compound refers to a compound containing a pyridine structure.

[0119] In the present specification, an imidazole-based compound refers to a compound containing an imidazole structure.

[0120] In the present specification, a triazole-based compound refers to a compound containing a triazole structure.

[0121] In one embodiment of the present specification, the above nitrogen-containing heterocyclic compound may be (di)alkylaminopyridine, alkylimidazole, or alkyltriazole.

[0122] In one embodiment of the present specification, the above nitrogen-containing heterocyclic compound may be (di)alkylaminopyridine or alkylimidazole.

[0123] In one embodiment of the present specification, the above nitrogen-containing heterocyclic compound may be 4-(dimethylamino)pyridine or 1-methylimidazole.

[0124] In one embodiment of the present specification, based on 100 parts by weight of the whole of the above pre-rinse solution, 0.1 part by weight to 1.5 parts by weight of the above nitrogen-containing heterocyclic compound may be included.

[0125] In one embodiment of the present specification, based on 100 parts by weight of the whole of the above pre-rinse solution, 0.3 part by weight to 1.5 parts by weight, 0.5 part by weight to 1.3 parts by weight, or 0.7 part by weight to 1.2 parts by weight of the above nitrogen-containing heterocyclic compound may be included.

[0126] When the above nitrogen-containing heterocyclic compound is used in an amount of less than 0.1 part by weight, it cannot be sufficiently combined with the unreacted monomer and the above effects cannot be expected. When it exceeds 1.5 parts by weight, no performance improvement effect according to the increase is confirmed. That is, it is effective to use the above nitrogen-containing heterocyclic compound within the above content range.

[0127] In one embodiment of the present specification, the above pre-rinse solution may further contain a solvent.

[0128] In one embodiment of the present specification, the solvent of the above pre-rinse solution may be water or an alcohol.

[0129] In one embodiment of the present specification, the solvent of the above pre-rinse solution may be water.

[0130] In one embodiment of the present specification, the remaining components of the above pre-rinse solution other than the above nitrogen-containing heterocyclic compound may be a solvent.

[0131] In one embodiment of the present specification, the above pre-rinse solution may be composed of the above nitrogen-containing heterocyclic compound and a solvent.

[0132] In one embodiment of the present specification, the washing method in the above step of washing the polyamide active layer with the pre-rinse solution is not particularly limited, and a method applicable in the present technical field may be appropriately adopted. For example, the above polyamide active layer may be immersed in the above pre-rinse solution for 1 second to 10 seconds.

[0133] According to the manufacturing method of the water treatment separation membrane of one embodiment of the present specification, after the above step of washing with the pre-rinse solution, it may further include a step of washing the above polyamide active layer in water. By washing the above polyamide active layer in water again, residues that were not removed in the above pre-rinse step can also be removed.

[0134] In one embodiment of the present specification, the washing method in the above step of washing the polyamide active layer in water is not particularly limited, but a method applicable in the present technical field may be appropriately adopted. For example, the above polyamide active layer may be immersed in water at 50°C to 80°C for 5 minutes.

[0135] The manufacturing method of the water treatment separation membrane according to one embodiment of the present specification may further include a step of forming a protective layer on the above polyamide active layer.

[0136] In one embodiment of the present specification, the step of forming the above-mentioned protective layer may include the step of bringing the above-mentioned polyamide active layer into contact with an aqueous solution for forming the protective layer.

[0137] In one embodiment of the present specification, the step of bringing the above-mentioned polyamide active layer into contact with the aqueous solution for forming the protective layer may be carried out by methods such as dipping, slot-die coating, bank coating, gravure coating, etc., but is not limited thereto.

[0138] In one embodiment of the present specification, the step of bringing the above-mentioned polyamide active layer into contact with the aqueous solution for forming the protective layer may be the step of dipping the above-mentioned polyamide active layer in the aqueous solution for forming the protective layer.

[0139] In one embodiment of the present specification, the step of dipping the above-mentioned polyamide active layer in the aqueous solution for forming the protective layer may be carried out for 10 seconds to 5 minutes, or 30 seconds to 2 minutes.

[0140] In addition, as needed, after dipping in the aqueous solution for forming the protective layer, the step of drying in an oven at 90°C for 3 minutes may also be carried out.

[0141] In one embodiment of the present specification, the aqueous solution for forming the protective layer may contain one or more of glycerol, polyvinyl alcohol (PVA), and polyvinylpyrrolidone (PVP).

[0142] In one embodiment of the present specification, the aqueous solution for forming the protective layer may contain glycerol.

[0143] In one embodiment of the present specification, the aqueous solution for forming the protective layer may contain glycerol at a concentration of 1% to 30%.

[0144] In one embodiment of the present specification, the aqueous solution for forming the protective layer may contain glycerol at a concentration of 1% to 20%.

[0145] In one embodiment of the present specification, the aqueous solution for forming the protective layer may contain the above-mentioned glycerol at a concentration of 5% to 15%.

[0146] In one embodiment of the present specification, the aqueous solution for forming the protective layer may further contain a solvent, and the solvent may be water, but is not limited thereto.

[0147] In one embodiment of the present specification, the thickness of the above-mentioned protective layer is not particularly limited, and the overall thickness of the water treatment separation membrane may be suitably formed within a range satisfying 100 μm or more and 250 μm or less.

[0148] In one embodiment of the present specification, the salt rejection rate of the above water treatment separation membrane measured under the conditions of a 2000 ppm aqueous NaCl solution, a pressure of 125 psi, a temperature of 25 °C, and a flow rate of 4 L / minute can be 99.4% or more, and the permeate flux can be 20.8 GFD or more.

[0149] In one embodiment of the present specification, the permeate flux of the above water treatment separation membrane measured under the conditions of a 2000 ppm aqueous NaCl solution, a pressure of 125 psi, a temperature of 25 °C, and a flow rate of 4 L / minute can be 20.80 GFD or more, 22.00 GFD or more, 25.00 GFD or more, 26.00 GFD or more, or 27.00 GFD or more. There is no upper limit, but it can be 40.0 GFD or less, 39.0 GFD or less, or 38 GFD or less.

[0150] In one embodiment of the present specification, the permeate flux of the above water treatment separation membrane measured under the conditions of a 2000 ppm aqueous NaCl solution, a pressure of 125 psi, a temperature of 25 °C, and a flow rate of 4 L / minute can be 20.80 GFD or more and 40.0 GFD or less, 22.00 GFD or more and 39 GFD or less, or 25.00 GFD or more and 38 GFD or less.

[0151] In one embodiment of the present specification, the salt rejection rate of the above water treatment separation membrane measured under the conditions of a 2000 ppm aqueous NaCl solution, a pressure of 125 psi, a temperature of 25 °C, and a flow rate of 4 L / minute can be 99.40% or more, 99.43% or more, 99.45% or more, or 99.46% or more. There is no upper limit specified, but it can be 100% or less, 99.9% or less.

[0152] That is, the water treatment separation membrane manufactured according to one embodiment of the present specification ensures a minimum salt rejection rate of 99.40%, and at the same time provides a minimum permeate flux of 20.8 GFD or more. When compared with the water treatment separation membrane not manufactured according to one embodiment of the present specification, not only is the salt rejection rate hardly reduced, but the permeate flux is also improved.

[0153] Generally, the relationship between the salt rejection rate and the permeate flux is that if the permeate flux is improved, the salt rejection rate decreases. However, in the case of using the water treatment separation membrane manufactured by the manufacturing method of the present invention, while increasing the permeate flux, the decrease in the salt rejection rate can be minimized.

[0154] In this specification, for the measurement of the above permeation flux and salt rejection rate, after the equipment operation for about 1 hour is carried out on the brine to be evaluated (for example, an aqueous solution of NaCl at 2000 ppm) under specific pressure conditions (for example, 125 psi) and flow conditions (for example, 4 L / minute) and stabilization is confirmed, the amount of water permeated in 10 minutes at 25 °C is measured, and the permeation flux (Flux, GFD) is calculated. The conductivity meter is used to analyze the conductivity of the raw water and the salt concentration of the post-treatment water after permeation, so as to calculate the salt rejection rate (Rejection, %).

[0155] In this specification, the unit of the permeation flux is GFD (gallons / ft 2 / day (gallons / ft 2 / day)).

[0156] Another embodiment of this specification provides a water treatment separation membrane manufactured by the above manufacturing method of the water treatment separation membrane.

[0157] The water treatment separation membrane manufactured by the manufacturing method according to an embodiment of this specification includes: a porous layer, and a polyamide active layer provided on the porous layer.

[0158] The water treatment separation membrane manufactured by the manufacturing method according to another embodiment of this specification includes: a porous layer, a polyamide active layer provided on the porous layer, and a protective layer provided on the polyamide active layer.

[0159] The water treatment separation membrane manufactured by the manufacturing method according to another embodiment of this specification includes: a first porous support, a second porous support provided on the first porous support, a polyamide active layer provided on the second porous support, and a protective layer provided on the polyamide active layer.

[0160] The specific descriptions of the porous layer, the polyamide active layer, and the protective layer are the same as the above descriptions.

[0161] Figure 1 A water treatment separation membrane according to an embodiment of this specification is illustrated. Specifically, Figure 1 A water treatment separation membrane in which a porous layer including a first porous support 100 and a second porous support 200 and a polyamide active layer 300 are sequentially provided is illustrated. Brine 400 flows into the polyamide active layer 300, purified water 500 is discharged through the first porous support 100, and concentrated water 600 cannot pass through the polyamide active layer 300 and is discharged to the outside. The water treatment separation membrane according to an embodiment of this specification is not limited to Figure 1 the structure, and may also include additional components.

[0162] In one embodiment of the present specification, the thickness of the above-mentioned water treatment separation membrane may be 100 μm or more and 250 μm or less. When the thickness of the above-mentioned water treatment separation membrane is within the above range, the salt rejection rate and permeation flux of the water treatment separation membrane to be achieved in the present specification can be appropriately maintained. When the thickness of the above-mentioned water treatment separation membrane is less than 100 μm, the permeation flux of the water treatment separation membrane increases but the salt rejection rate may decrease. When the thickness of the above-mentioned water treatment separation membrane is greater than 250 μm, the salt rejection rate of the water treatment separation membrane increases but the permeation flux may decrease.

[0163] The thickness of the above-mentioned water treatment separation membrane may be the thickness of the water treatment separation membrane including a porous layer and a polyamide active layer. In the case of including a protective layer, it may be the thickness of the water treatment separation membrane including a porous layer, a polyamide active layer, and a protective layer.

[0164] Another embodiment of the present specification provides a water treatment module including one or more of the above-mentioned water treatment separation membranes.

[0165] The number of water treatment separation membranes included in the above-mentioned water treatment module may be from 1 to 50, may be from 1 to 30, and preferably may be from 24 to 28, but is not limited thereto.

[0166] The specific type of the above-mentioned water treatment module is not particularly limited. Among its examples, it includes a plate & frame module, a tubular module, a hollow fiber module, or a spiral wound module, etc. In addition, as long as the above-mentioned water treatment module includes the water treatment separation membrane manufactured according to one embodiment of the present specification, there are no particular restrictions on other constitutions and manufacturing methods, etc., and conventional methods well-known in the art can be adopted without limitation.

[0167] On the other hand, the water treatment module according to one embodiment of the present specification has excellent salt rejection rate and permeation flux, and excellent chemical stability, and thus can be usefully used in water treatment devices such as household / industrial water purification devices, sewage treatment devices, seawater desalination treatment devices, etc.

[0168] Hereinafter, examples will be given to specifically illustrate the present specification. However, the examples according to the present specification can be deformed into various different forms, and the scope of the present specification is not construed as being limited to the examples described in detail below. The examples of the present specification are provided to more comprehensively illustrate the present specification to those skilled in the art.

[0169] <Manufacturing Example> Manufacture of Water Treatment Separation Membrane

[0170] An amine aqueous solution (remaining component: water) was prepared using the composition described in Table 1 below, and an acyl halide organic solution containing 0.05 - 0.5 wt% of TMC, 87.5 - 99.5 wt% of Isopar G, and 0 - 10 wt% of an organic co-solvent was prepared. The above amine aqueous solution was coated on a UF support (with a thickness of 100 - 200 μm) to form an aqueous solution layer. After 10 seconds, the excess aqueous solution was removed by an air knife. Then, the above acyl halide organic solution was coated on the aqueous solution layer. After 10 seconds, it was dried in an oven at 90°C for 3 minutes to form a polyamide active layer (0.2 - 0.4 μm). Then, it was washed with a pre-rinse solution (remaining component: water) containing the compound described in Table 1 below for 5 seconds to remove the residues remaining on the active layer. After that, it was immersed in water at 80°C for 5 minutes to remove the residues again. After the active layer was immersed in a 10% glycerol solution for 1 minute, it was dried in an oven at 90°C for 3 minutes, thereby manufacturing a water treatment separation membrane.

[0171]

Table 1

[0172]

[0173] *m-PD: m-phenylenediamine

[0174] *A-1: sodium carbonate

[0175] *A-2: 4-(dimethylamino)pyridine

[0176] *A-3: 1-methylimidazole

[0177] <Experimental Example> Evaluation of the water treatment separation membrane (measurement of flux and salt rejection rate)

[0178] For the water treatment separation membrane manufactured in the above manufacturing example, after the equipment was operated for about 1 hour with a 2000 ppm NaCl aqueous solution at a flow rate of 125 psi and 4 L / min to confirm stabilization, the amount of water permeated in 10 minutes at 25°C was measured, and the permeation flux (Flux, GFD) was calculated. The conductivity meter was used to analyze the conductivity of the raw water and the salt concentration of the treated water after permeation. The results of calculating the salt rejection rate (Rejection, %) are shown in Table 2 below.

[0179]

Table 2

[0180]

[0181] The permeation flux of the water treatment separation membrane manufactured according to the present invention was confirmed to be excellent compared to Comparative Examples 1 and 2 by the results of Table 2 above. Specifically, it was found that the production of Comparative Example 1 did not include a pre-rinse step, and the permeation flux was significantly lower compared to the example group of the present invention.

[0182] In addition, it was found that although Comparative Example 2 included a pre-rinse step, a solution containing sodium carbonate instead of the nitrogen-containing heterocyclic compound of the present invention was used, and its permeation flux did not increase significantly either.

[0183] On the contrary, it was confirmed that the permeation fluxes of Examples 1 to 6 increased by an average of 20% compared to the comparative example group. When Example 2 and Example 7 in the examples were compared, the use of a pyridine-based additive further increased the permeation flux.

[0184] In addition, by comparing Example 1 with Examples 2 to 5, in the case of including a pre-rinse step and further including an amine-based additive in the amine aqueous solution and appropriately adjusting the content of the amine compound, the increase in the permeation flux can be maximized.

Claims

1. A manufacturing method of a water treatment separation membrane, comprising: A step of forming a polyamide active layer by coating an aqueous amine solution and an organic acyl halide solution on a porous layer; and A step of washing the polyamide active layer with a pre-rinse solution, wherein the pre-rinse solution contains a nitrogen-containing heterocyclic compound, and the nitrogen-containing heterocyclic compound is (di)alkylaminopyridine, alkylimidazole or alkyltriazole.

2. The manufacturing method of the water treatment separation membrane according to claim 1, wherein, The nitrogen-containing heterocyclic compound is (di)alkylaminopyridine or alkylimidazole.

3. The manufacturing method of the water treatment separation membrane according to claim 1, wherein, Based on 100 parts by weight of the whole pre-rinse solution, it contains 0.1 to 1.5 parts by weight of the nitrogen-containing heterocyclic compound.

4. The manufacturing method of the water treatment separation membrane according to claim 1, wherein, The pre-rinse solution further contains a solvent.

5. The manufacturing method of the water treatment separation membrane according to claim 1, wherein, The aqueous amine solution contains an amine compound, an amine-based additive and a solvent.

6. The manufacturing method of the water treatment separation membrane according to claim 5, wherein, The amine-based additive includes one or more selected from aminophenol, amino alcohol and aminobenzoic acid.

7. The manufacturing method of the water treatment separation membrane according to claim 5, wherein, Based on 100 parts by weight of the whole aqueous amine solution, it contains 0.01 to 0.2 parts by weight of the amine-based additive.

8. The manufacturing method of the water treatment separation membrane according to claim 1, wherein, It further includes a step of forming a protective layer on the polyamide active layer.

9. The manufacturing method of the water treatment separation membrane according to claim 8, wherein, The step of forming the protective layer includes a step of coating an aqueous solution for forming the protective layer on the polyamide active layer.

10. The manufacturing method of the water treatment separation membrane according to claim 9, wherein, The aqueous solution for forming the protective layer contains glycerol at a concentration of 1% to 30%.

11. The manufacturing method of the water treatment separation membrane according to claim 1, wherein, The water treatment separation membrane has a desalination rate of 99.40% or more and a permeate flux of 20.8 GFD or more when measured under the conditions of a 2000 ppm NaCl aqueous solution, a pressure of 125 psi, a temperature of 25 °C, and a flow rate of 4 L / min.

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