KR102056873B1 - membrane and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a separation membrane and a method for manufacturing the same, and more particularly, to a separation membrane and a method for manufacturing the same to reduce the degradation of physical properties and performance due to physical damage of the membrane surface during the module processing process of the separation membrane.

Description

Separation membrane and manufacturing method thereof

The present invention relates to a separation membrane and a method for manufacturing the same, and more particularly, to a separation membrane and a method for manufacturing the same to reduce the degradation of physical properties and performance due to physical damage of the membrane surface during the module processing process of the separation membrane.

In general, a method of separating various components such as fine impurities and ions present in a liquid includes evaporation, electrodialysis, microfiltration, ultrafiltration, and reverse osmosis. Among them, reverse osmosis has the advantage of low energy consumption, small and large sized facilities can be constructed, and even monovalent ions in water can be removed.

In general, the membrane used in the reverse osmosis method is a nano-membrane or reverse osmosis membrane, wherein the reverse osmosis membrane is composed of a support layer for maintaining mechanical strength and an active layer having a selective permeability, recently the aromatic polysulfone as a porous support layer Reverse osmosis membranes comprising polyamides as active layers have been developed and commercialized. The reverse osmosis membrane may be prepared by a thin layer dispersion method, an immersion coating method, a vapor deposition method, a Langmuir-Blodgett method, an interfacial polymerization method, and the most commonly used method is cadote. Interfacial polymerization described by US Patent No. 4,277,344. This invention discloses a technique for an aromatic polyamide composite membrane obtained by interfacial polymerization of an aromatic polyfunctional amine containing at least two primary amine substituents and an aromatic acyl halide having at least three acyl halide substituents.

In a preferred embodiment, after coating the porous polysulfone support layer with m-phenylendiamine dissolved in water, the excess metaphenylenediamine solution is removed from the coated porous support, and the coated support is By contacting with a trimezoyl chloride solution dissolved in Freon TF solvent (trichlorotrifluoroethane), polysulfone / polyamide composite membranes are described to have good permeate flux and salt removal rate. However, the flow rate and salt removal rate required by the continuous reverse osmosis membrane technology are increasing, and researches to further improve the salt removal rate by introducing surface treatment technology after interfacial polymerization or to improve performance degradation due to changes over time It's going on.

As an improvement technique for this, the wetting agent for the membrane which can prevent the change of the properties of the membrane generated when the membrane is stored, stored, transported and managed in Korea Publication No. 2015-0079225, and the dry preservation treatment method of the membrane using the same and using the same There is a description of a membrane with improved change over time, which does not provide a solution to the problem that affects the membrane performance, especially the removal rate when a physical impact from the outside occurs.

As another improvement technique, the surface of the coating with a composition containing a glycerin compound, polyvinyl alcohol (PVA) and alcohol is disclosed in Korean Laid-Open Publication No. 2015-0076123, so that the moisture content and peel strength are excellent in a dry state, and thus the salt removal rate And a polyamide-based dry water treatment membrane having excellent permeate flow rate and a method of manufacturing the same. This technique has a disadvantage in that it affects the film formation variation depending on the presence or absence of alcohol used as a solvent, and may be exposed to danger if the membrane treated with the alcohol is subjected to a drying process.

The present invention has been made in view of the above, by forming a coating layer containing a specific material on one surface of the active layer, the separation membrane to improve the problem of physical properties of the membrane surface damage caused during the module processing process of the separator and An object of the present invention is to provide a method for producing a separator.

In addition, an object of the present invention is to provide a separation membrane and a method of manufacturing the same, which minimizes the tendency of flow rate reduction before and after surface treatment on the separation membrane.

In order to solve the above problems, the separator of the present invention is a porous support layer, the active layer and the coating layer are sequentially stacked, the coating layer may include glycerol, preservatives and polyvinyl alcohol.

In one preferred embodiment of the present invention, the coating layer may include glycerol, preservatives and polyvinyl alcohol in a weight ratio of 1: 1 to 10: 0.0003 to 1.5.

As a preferred embodiment of the present invention, the coating layer may include glycerol, preservatives and polyvinyl alcohol in a weight ratio of 1: 1 to 10: 0.1 to 1.5.

As a preferred embodiment of the present invention, the polyvinyl alcohol may have a weight average molecular weight of 150,000 or less.

As a preferred embodiment of the present invention, the polyvinyl alcohol may have a degree of saponification of 75 to 90 mol%.

As a preferred embodiment of the present invention, the preservative may include one or more of sugar alcohols having 5 to 6 hydroxyl groups, monosaccharides having 5 to 6 hydroxyl groups, polysaccharides having 5 to 6 hydroxyl groups, and inorganic salts. have.

In one preferred embodiment of the present invention, the sugar alcohol having 5 to 6 hydroxyl groups is one or more of sorbitol, mannitol, inositol, xylitol, bornesitol, mithitol, silitol, sequotol and laminitol Wherein the monosaccharide having 5 to 6 hydroxyl groups comprises at least one of glucose, fructose and galactose, and the polysaccharide having 5 to 6 hydroxyl groups comprises at least one of squarose, maltose and lactose. The inorganic salt may include at least one of sodium carbonate, sodium sulfate, sodium phosphate, potassium chloride, magnesium chloride, magnesium sulfate, and calcium chloride.

In a preferred embodiment of the present invention, the active layer may comprise at least one hydrophobic compound of polyamide, polyimide, polysulfone and polyether sulfone.

In one preferred embodiment of the present invention, the active layer may include a polyamide formed by interfacial polymerization of a polyfunctional amine containing solution and a polyfunctional halogen compound containing solution.

In a preferred embodiment of the present invention, the multifunctional amine comprises at least one of metaphenylenediamine, paraphenylenediamine, aliphatic primary diamine, cycloaliphatic primary diamine and cycloaliphatic secondary amine The polyfunctional halogen compound may include at least one of trimezoyl chloride, isophthaloyl chloride and terephthaloyl chloride.

As a preferred embodiment of the present invention, the separation membrane may be a reverse osmosis membrane, ultrafiltration membrane, nanofiltration membrane or microfiltration membrane.

As a preferred embodiment of the present invention, the separator of the present invention may satisfy the following equation 1.

Equation 1

[Salt removal rate before surface damage of membrane (%)-Salt removal rate after surface damage of membrane (%)] ≤ 1.0

In Equation 1, the salt removal rate is measured based on Equation 1 below in an aqueous solution containing 200 ppm of NaCl at a temperature of 20 to 35 ° C., a pressure of 50 to 70 psi, and a recovery rate of 20 to 40%. Raise a 32 mil thick mesh material and damage it by applying a pressure of 1-5 kgf / cm ² ;

[Equation 1]

Salt Removal Rate (%) = (1- (Cp / Cf)) ⅹ 100

In Equation 1, Cp is the salt concentration of the membrane permeate, Cf is the salt concentration of the raw water.

On the other hand, the manufacturing method of the separator of the present invention is wetted by immersing the porous support layer having an active layer formed on one side or both sides in the separator wetting agent and the porous support layer on which the wet treated active layer is formed and dried on one surface of the active layer Including a second step of forming a coating layer, the separator wetting agent may be a mixture of glycerol, preservatives and polyvinyl alcohol.

As a preferred embodiment of the present invention, the wetting agent for the membrane is mixed with glycerol, preservatives and polyvinyl alcohol in a weight ratio of 1: 1 to 10: 0.0003 to 1.5, the polyvinyl alcohol has a weight average molecular weight of 150,000 or less, saponification The degree of saponification may be 75 to 90 mol%.

As a preferred embodiment of the present invention, the immersion of the first step may be performed for 10 seconds to 30 minutes at a temperature of 10 ~ 55 ℃, the drying of the second step 30 seconds at a temperature of 20 ~ 110 ℃ Can run for 1 hour.

As a preferred embodiment of the present invention, the active layer may be formed on one or both surfaces of the porous support layer by applying a polyfunctional amine-containing solution on one or both surfaces of the porous support layer, and interfacial polymerization of the halogen compound-containing solution.

In the separation membrane and the method for preparing the separation membrane of the present invention, the tendency of flow decrease before and after surface treatment on the separation membrane is minimized.

In addition, the separation membrane of the present invention and the manufacturing method of the separation membrane has the advantage that the change in the salt removal rate before and after physical damage pressing.

In addition, the manufacturing method of the separator of the present invention can easily form a coating layer on one surface of the active layer without a separate coating process.

1 is a view of the surface of the prepared reverse osmosis membrane in general, Figure 1a is a view taken by using a scanning electron microscope (SEM) the surface of the reverse osmosis membrane before the cutting, polling, rolling process 1B is a diagram of the surface of the reverse osmosis membrane after the cutting, polling, and rolling process is photographed using a scanning electron microscope (SEM).
2 is a view showing the surface of the reverse osmosis membrane prepared in Example 2 after the physical damage is pressed by using a scanning electron microscope (SEM) as a preferred specific embodiment of the present invention.
FIG. 3 is a photograph taken by scanning electron microscopy (SEM) of the surface after physical damage pressing on the reverse osmosis membrane prepared in Comparative Example 1.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

The production process of reverse osmosis membrane, which is mainly manufactured in spiral wound module form, is rolled after cutting and folding according to product size after membrane inspection operation to visually check the state of the coated membrane. After rolling, tape work and trimming to remove both ends of the module. Finally, wrap the tape or fiberglass to fix the shape to complete the product. During this process, the performance of the actual product is deteriorated due to physical damage such as film surface scratch, rolling, and mesh stamping, which are mainly generated during cutting, folding, and rolling processes.

Specifically, referring to Figure 1, Figure 1a is a view taken by using a scanning electron microscope (SEM) the surface of the reverse osmosis membrane before the cutting, polling, rolling process, Figure 1b is cutting, polling After the rolling process, the surface of the reverse osmosis membrane was photographed using a scanning electron microscope (SEM). As can be seen in Figure 1b, it was confirmed that the surface of the reverse osmosis membrane is damaged through the cutting, polling, rolling process. Therefore, the separation membrane of the present invention and a method of manufacturing the same for solving such a problem are as follows.

The separator of the present invention is a separator in which a porous support layer, an active layer and a coating layer are sequentially stacked.

First, the porous support layer may be a polymer material coated on a nonwoven fabric, and the polymer material may be polysulfone, polyethersulfone, polycarbonate, polyethylene oxide, polyimide, polyetherimide, polyether ketone, polypropylene, poly It may comprise one or more of methylpentene, polymethylchloride and polyvinylidene fluoride, preferably polysulfone. However, the polymer material which may be included in the porous support layer is not limited thereto.

Next, the active layer may comprise at least one hydrophobic compound of polyamide, polyimide, polysulfone and polyether sulfone, preferably may include polyamide, more preferably with a polyfunctional amine containing solution. The polyamide formed by interfacial polymerization of a solution containing a polyfunctional halogen compound may be included.

In this case, the polyfunctional amine may include at least one of metaphenylenediamine, paraphenylenediamine, aliphatic primary diamine, cycloaliphatic primary diamine, and cycloaliphatic secondary amine, preferably meta Phenylenediamine.

In addition, the polyfunctional halogen compound may include at least one of trimezoyl chloride, isophthaloyl chloride and terephthaloyl chloride.

Next, the coating layer may include glycerol, preservatives and polyvinyl alcohol. In addition, the coating layer may further include water, and the content of water may be relatively determined according to the amount of glycerol, preservative and polyvinyl alcohol used.

At this time, glycerol serves as the main humectant.

The preservative serves to absorb moisture in the air, and may include at least one of sugar alcohols having 5 to 6 hydroxyl groups, monosaccharides having 5 to 6 hydroxyl groups, polysaccharides having 5 to 6 hydroxyl groups, and inorganic salts. It may preferably include one or more of sugar alcohols and inorganic salts having 5 to 6 hydroxyl groups, more preferably may include sugar alcohols having 5 to 6 hydroxyl groups.

The sugar alcohol having 5 to 6 hydroxyl groups may include at least one of sorbitol, mannitol, inositol, xylitol, bornestitol, mithitol, silitol, sequotol and laminitol, preferably sorbitol It may include one or more of mannitol and inositol, more preferably may include one or more of sorbitol and mannitol.

In addition, the monosaccharide having 5 to 6 hydroxyl groups may include at least one of glucose, fructose and galactose, and the polysaccharide having 5 to 6 hydroxyl groups is at least one of squarose, maltose and lactose. It may include, the inorganic salt may include at least one of sodium carbonate, sodium sulfate, sodium phosphate, potassium chloride, magnesium chloride, magnesium sulfate and calcium chloride.

Polyvinyl alcohol is included in the coating layer, thereby protecting the active layer. The polyvinyl alcohol may have a weight average molecular weight of 150,000 or less, preferably 5,000 to 100,000, and more preferably 10,000 to 50,000. If the weight average molecular weight of polyvinyl alcohol exceeds 150,000, there is a problem in that it takes a long time to dissolve in water, such that it must be dissolved at a high temperature rather than room temperature, there may be a problem in the application process.

In addition, the polyvinyl alcohol may have a degree of saponification of 75 to 90 mol%, preferably 80 to 88 mol%, and if the degree of saponification is less than 75 mol%, it starts before hydrolysis other than polyvinyl alcohol. There is a problem that contains a large amount of material, if more than 90 mol% may be difficult to apply to the process is not dissolved in water.

On the other hand, the coating layer may include glycerol, preservatives and polyvinyl alcohol.

In addition, the coating layer is a glycerol, a preservative and a polyvinyl alcohol in a weight ratio of 1: 1 to 10: 0.0003 to 1.5, preferably 1: 1 to 10: 0.1 to 1.5, and more preferably 1: 1 to 5: 0.2 to 1.3. It may be included in the weight ratio, even more preferably 1: 1 to 3: 0.7 to 1.0 weight ratio. If the preservative is less than 1 weight ratio with respect to 1 weight ratio of glycerol, there may be a problem in that the flow rate of the separation membrane is reduced, and if it exceeds 10 weight ratio, the physical properties of the separation membrane may be degraded and there may be difficulty in drying in the manufacturing process. In addition, when the polyvinyl alcohol is less than 0.0003 weight ratio with respect to 1 weight ratio of glycerol, there may be a problem that the rate of change of salt removal rate is significantly increased, and when the weight ratio exceeds 1.5 weight ratio, there may be a problem that the flow rate is significantly reduced.

Meanwhile, the separation membrane of the present invention may be a reverse osmosis membrane, an ultrafiltration membrane, a nanofiltration membrane or a microfiltration membrane, preferably a reverse osmosis membrane.

Furthermore, the separator of the present invention is an aqueous solution containing 200ppm NaCl temperature 20 ~ 35 ℃, preferably 23 ~ 26 ℃, pressure 50 ~ 70psi, preferably 57 ~ 63psi and recovery rate 20 ~ 40%, preferably When measured under 27-33% conditions, the permeate flow rate may be 10-17 gfd, preferably 12-16 gfd.

In addition, the separator of the present invention may satisfy the following equation 1.

Equation 1

[Salt removal rate before surface damage of membrane (%)-Salt removal rate after surface damage of membrane (%)] ≤ 1.0, preferably [Salt removal rate before surface damage of membrane (%)-Salt removal rate after surface damage of membrane (%) )] ≤ 0.5, more preferably 0.2 ≤ [% salt removal rate before surface damage of membrane-% salt removal rate after surface damage of membrane] ≤ 0.5

In the equation 1, the salt removal rate is an aqueous solution containing 200 ppm of NaCl at a temperature of 20 to 35 ° C., preferably 23 to 26 ° C., a pressure of 50 to 70 psi, preferably 57 to 63 psi, and a recovery rate of 20 to 40%, preferably It can be measured based on the following equation (1) under 27 ~ 33% conditions.

[Equation 1]

Salt Removal Rate (%) = (1- (Cp / Cf)) ⅹ 100

In Equation 1, Cp is the salt concentration of the membrane permeate, Cf is the salt concentration of the raw water.

In addition, the surface damage of the separator in Equation 1 is a mesh material of 23 ~ 32 mil, preferably 26 ~ 30 mil thick on the surface of the separator, a pressure of 1 ~ 5kgf / cm ² , preferably It can be damaged by applying a pressure of 2-4 kgf / cm ² .

On the other hand, the method of manufacturing a separator of the present invention includes a first step and a second step.

The first step of the method for producing a separator of the present invention may be wet treatment by immersing the porous support layer having an active layer formed on one side or both sides in a separator wetting agent.

Specifically, the active layer may be formed on one side or both sides of the porous support layer by applying a polyfunctional amine-containing solution on one or both sides of the porous support layer, and interfacially polymerizing the halogen compound-containing solution. In addition, after the active layer is formed on the porous support layer before performing the first step, a cleaning process for removing residual chemical may be additionally performed.

The wetting agent for the separator of the first step may be a mixture of glycerol, preservatives and polyvinyl alcohol, preferably may be a mixture of glycerol, preservatives and polyvinyl alcohol in a weight ratio of 1: 1 ~ 10: 0.0003 ~ 1.5, More preferably, glycerol, a preservative, and polyvinyl alcohol may be mixed in a weight ratio of 1: 1 to 10: 0.1 to 1.5.

At this time, the wetting agent for the membrane may be further mixed with water, the amount of water may be relatively determined according to the amount of glycerol, preservatives and polyvinyl alcohol used.

In addition, the polyvinyl alcohol of the first stage may have a weight average molecular weight of 150,000 or less, preferably 5,000 to 100,000, more preferably 10,000 to 50,000, and further, the polyvinyl alcohol of the first stage The degree of saponification may be 75 to 90 mol%, preferably 80 to 88 mol%.

In addition, the immersion of the first step may be carried out for 10 seconds to 30 minutes, preferably 20 seconds to 10 minutes at a temperature of 10 ~ 55 ℃, preferably 15 ~ 45 ℃, if the immersion time is 10 Less than a second may be a problem that is not sufficiently wetted, and more than 30 minutes may be a non-economic problem.

Next, in the second step of the method of manufacturing a separator of the present invention, the porous support layer in which the active layer wetted in the first step is formed may be dried to form a coating layer on one surface of the active layer.

The drying of the second step may be carried out at a temperature of 20 ~ 110 ℃, preferably 50 ~ 100 ℃, if the drying temperature is less than 20 ℃ takes too long drying time, if it exceeds 110 ℃ to the separation membrane There is a problem that thermal deformation may occur. In addition, the drying time may be fluid, depending on the drying temperature, preferably 30 seconds to 1 hour, more preferably from 1 to 10 minutes is good from the commercial point of view.

The present invention has been described above with reference to the embodiments, which are merely exemplary and are not intended to limit the embodiments of the present invention. Those of ordinary skill in the art to which the embodiments of the present invention belong will have the essential characteristics of the present invention. It will be appreciated that various modifications and applications not illustrated above are possible without departing from the scope of the invention. For example, each component specifically shown in the embodiment of the present invention may be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

Example 1 Preparation of Membrane

(1) A polyfunctional amine-containing solution was applied to one surface of the porous support layer, and the excess solution was removed, followed by contact reaction with the polyfunctional reactive compound-containing solution to form an active layer, and washed with distilled water.

(2) 1% by weight of glycerol, 1% by weight of sorbitol, a weight average molecular weight of 20,000, 1% by weight of polyvinyl alcohol having a saponification degree of 88 mol%, and 97% by weight of water, and a porous support layer having an active layer formed therein. Was soaked at 25 ° C. for 1 minute.

(3) The porous support layer having the immersed active layer was taken out, the excess solution was removed, and dried at 60 ° C. for 4 minutes to form a coating layer, thereby preparing a dry reverse osmosis membrane.

Example 2 Preparation of Membrane

Dry reverse osmosis membrane was prepared in the same manner as in Example 1. However, a separatory wetting agent was used, in which 1% by weight of glycerol, 1% by weight of sorbitol, a weight average molecular weight of 20,000, and 0.7% by weight of polyvinyl alcohol having a saponification degree of 88 mol% and 97.3% by weight of water were mixed.

Example 3 Preparation of Membrane

Dry reverse osmosis membrane was prepared in the same manner as in Example 1. However, a 1% by weight glycerol, 1% by weight sorbitol, a weight average molecular weight of 20,000, 0.2% by weight of polyvinyl alcohol having a saponification degree of 88 mol% and 97.8% by weight of water were used as a separator wetting agent.

Example 4 Preparation of Membrane

Dry reverse osmosis membrane was prepared in the same manner as in Example 1. However, 1 wt% of glycerol, 1 wt% of sorbitol, weight average molecular weight of 200,000, and 1 wt% of polyvinyl alcohol having a saponification degree of 88 mol% and 97 wt% of water were used as a separator wetting agent.

Example 5 Preparation of Membrane

Dry reverse osmosis membrane was prepared in the same manner as in Example 1. However, 1 wt% of glycerol, 1 wt% of sorbitol, a weight average molecular weight of 20,000, and 1 wt% of polyvinyl alcohol having a saponification degree of 95 mol% and 97 wt% of water were used.

Example 6 Preparation of Membrane

Dry reverse osmosis membrane was prepared in the same manner as in Example 1. However, a 1% by weight of glycerol, 1% by weight of sorbitol, a weight average molecular weight of 20,000, and 2.0% by weight of polyvinyl alcohol having a saponification degree of 88 mol% and 97% by weight of water were used as a separator wetting agent.

Example 7 Preparation of Membrane

Dry reverse osmosis membrane was prepared in the same manner as in Example 1. However, a wetting agent for membranes containing 1% by weight of glycerol, 1% by weight of sorbitol, 20,000 weight average molecular weight, and 0.008% by weight of polyvinyl alcohol having a saponification degree of 88 mol% and 97.992% by weight of water was used.

Comparative Example 1: Preparation of Separator

Dry reverse osmosis membrane was prepared in the same manner as in Example 1. However, without using polyvinyl alcohol, a wetting agent for membranes in which 1% by weight of glycerol, 1% by weight of sorbitol and 98% by weight of water was mixed was used.

Experimental Example: Measurement of permeate flow rate, salt removal rate and salt removal rate change

The permeate flow rate and salt removal rate of the separators prepared in Examples and Comparative Examples were measured, and the results are shown in Table 1 below.

In addition, after raising the 28 mil thick mesh (mesh) material on the surface of the separator prepared in Examples and Comparative Examples, by pressing the surface by pressing under a pressure of 3kgf / cm ² using a drive roll physical Damage was added, and the salt removal rate of the separator prepared in Examples and Comparative Examples to which physical damage was applied was measured, and the results are shown in Table 1 below.

The salt removal rate was measured by operating an aqueous solution containing 200 ppm of NaCl for 1 hour at 25 ° C., a pressure of 60 psi, and a recovery rate of 30%. The salt removal rate was measured based on Equation 1 below.

[Equation 1]

Salt Removal Rate (%) = (1- (Cp / Cf)) ⅹ 100

In Equation 1, Cp is the salt concentration of the membrane permeate, Cf is the salt concentration of the raw water.

In addition, the measurement of permeate flow rate was carried out by operating 200ppm of tap water containing salt for 1 hour under the condition of temperature 25 ℃, pressure 60psi, and recovery rate 30%, and stabilizing for 30 minutes Was collected in a beaker for 30 minutes to measure the weight of the beaker later, the weight of the pure water produced by subtracting the weight of the beaker before sampling, and converted to volume.

As can be seen in Table 1, the separation membrane prepared in Examples 1 to 3 containing polyvinyl alcohol in the coating layer is significantly less salt removal rate change than the separator prepared in Comparative Example 1 does not include polyvinyl alcohol in the coating layer. I could confirm it.

Specifically, FIG. 2 is a view photographing the surface of the reverse osmosis membrane prepared in Example 2 after pressurizing physical damage using a scanning electron microscope (SEM), and FIG. 3 is a physical diagram of the reverse osmosis membrane prepared in Comparative Example 1. As a drawing of the surface after the damage pressurization using a scanning electron microscope (SEM), the reverse osmosis membrane prepared in Comparative Example 1 was confirmed that the pressing marks of the mesh is clear, the reverse osmosis prepared in Example 2 Separation membrane was confirmed that the pressing marks of the mesh is significantly relaxed.

In addition, the separator prepared in Example 5 using polyvinyl alcohol having a saponification degree of 95 mol% did not completely dissolve the solute of the solution, so that the formation of the coating layer on the active layer did not proceed properly, and the physical property measurement according to the experimental example was not performed. .

In addition, the separator prepared in Example 4 using a polyvinyl alcohol having a weight average molecular weight of 200,000 and 2.0 wt% of polyvinyl alcohol, the separator prepared in Example 6 comprises 0.2 to 1.0 wt% of polyvinyl alcohol. It was confirmed that the salt removal rate change was the same level than the separators prepared in Examples 1 to 3, but the flow rate was significantly reduced.

In addition, the separator prepared in Example 7 containing 0.008% by weight of polyvinyl alcohol can be confirmed that the change in salt removal rate is significantly smaller than the separator prepared in Examples 1 to 3 containing 0.2% to 1.0% by weight of polyvinyl alcohol. there was.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (15)

In the separator in which the porous support layer, the active layer and the coating layer are sequentially stacked,
The coating layer comprises glycerol, preservatives and polyvinyl alcohol in a weight ratio of 1: 1 to 10: 0.1 to 1.5,
The polyvinyl alcohol has a weight average molecular weight of 10,000 to 50,000, the degree of saponification is 75 to 90 mol%,
The separation membrane is a separation membrane, characterized in that the reverse osmosis membrane, ultrafiltration membrane, nanofiltration membrane or microfiltration membrane.
delete delete delete delete The method of claim 1,
The preservative includes at least one of sugar alcohols having 5 to 6 hydroxyl groups, monosaccharides having 5 to 6 hydroxyl groups, polysaccharides having 5 to 6 hydroxyl groups, and inorganic salts,
The sugar alcohol having 5 to 6 hydroxyl groups includes at least one of sorbitol, mannitol, inositol, xylitol, bornestitol, mithitol, silitol, sequotol and laminitol,
Monosaccharides having 5 to 6 hydroxyl groups include one or more of glucose, fructose and galactose,
The polysaccharide having 5 to 6 hydroxyl groups includes at least one of squarose, maltose and lactose,
The inorganic salt is a separation membrane comprising at least one of sodium carbonate, sodium sulfate, sodium phosphate, potassium chloride, magnesium chloride, magnesium sulfate and calcium chloride.
The method of claim 1,
The active layer is a separator, characterized in that it comprises at least one hydrophobic compound of polyamide, polyimide, polysulfone and polyether sulfone.
The method of claim 7, wherein
The active layer includes a polyamide formed by interfacial polymerization of a polyfunctional amine-containing solution and a polyfunctional halogen compound-containing solution,
The polyfunctional amine comprises at least one of metaphenylenediamine, paraphenylenediamine, aliphatic primary diamine, cycloaliphatic primary diamine and cycloaliphatic secondary amine,
The multifunctional halogen compound is a separation membrane, characterized in that it comprises at least one of trimezoyl chloride, isophthaloyl chloride and terephthaloyl chloride.
delete The method of claim 1,
The separation membrane is a separation membrane, characterized in that permeate flow rate of 10 ~ 17gfd when the aqueous solution containing 200ppm NaCl under the conditions of temperature 20 ~ 35 ℃, pressure 50 ~ 70psi and recovery rate 20 ~ 40%.
The method of claim 10,
The separation membrane is characterized in that for satisfying the following equation 1;
Equation 1
[Salt removal rate before surface damage of membrane (%)-Salt removal rate after surface damage of membrane (%)] ≤ 1.0
In Equation 1, the salt removal rate is measured based on Equation 1 below in an aqueous solution containing 200 ppm of NaCl at a temperature of 20 to 35 ° C., a pressure of 50 to 70 psi, and a recovery rate of 20 to 40%. Raise a 32 mil thick mesh material and damage it by applying a pressure of 1-5 kgf / cm ² ;
[Equation 1]
Salt Removal Rate (%) = (1- (Cp / Cf)) ⅹ 100
In Equation 1, Cp is the salt concentration of the membrane permeate, Cf is the salt concentration of the raw water.
A first step of immersing the porous support layer having an active layer formed on one or both surfaces thereof in a separator wetting agent; And
A second step of preparing a separator by drying the porous support layer on which the wet-treated active layer is formed to form a coating layer on one surface of the active layer; Including,
The separator wetting agent is mixed with glycerol, preservatives and polyvinyl alcohol in a weight ratio of 1: 1 to 10: 0.1 to 1.5,
The polyvinyl alcohol has a weight average molecular weight of 10,000 to 50,000, the degree of saponification is 75 to 90 mol%,
The separation membrane is a reverse osmosis membrane, ultrafiltration membrane, nanofiltration membrane or a method of manufacturing a separation membrane, characterized in that the microfiltration membrane.
delete The method of claim 12,
Immersion of the first step is carried out for 10 seconds to 30 minutes at a temperature of 10 ~ 55 ℃,
The drying of the second step is a method for producing a separator, characterized in that carried out for 30 seconds to 1 hour at a temperature of 20 ~ 110 ℃.
The method of claim 12,
The active layer is a method for producing a separator, characterized in that the polyfunctional amine-containing solution is applied to one or both surfaces of the porous support layer, and the halogenated compound-containing solution is formed on one or both surfaces of the porous support layer.

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