KR102209493B1 - Physical defects removed Reverse-osmosis membrane, method for manufacturing thereof and Reverse-osmosis module comprising thereof - Google Patents

Abstract

The present invention relates to a reverse osmosis membrane from which physical defects have been removed, a method of manufacturing the same, and a reverse osmosis module including the same.More specifically, the physical microdefects on the surface of the separator that may occur in the manufacturing process of the reverse osmosis membrane and the manufacturing process of the module using the same The present invention relates to a reverse osmosis membrane from which physical defects are removed, which prevents the deterioration of the salt removal rate of the reverse osmosis membrane due to the defect and extends the use period of the reverse osmosis membrane, a manufacturing method thereof, and a reverse osmosis module including the same.

Description

Physical defects removed Reverse-osmosis membrane, method for manufacturing thereof and Reverse-osmosis module comprising thereof

The present invention relates to a reverse osmosis membrane from which physical defects have been removed, a method of manufacturing the same, and a reverse osmosis module including the same.More specifically, the physical microdefects on the surface of the separator that may occur in the manufacturing process of the reverse osmosis membrane and the manufacturing process of the module using the same The present invention relates to a reverse osmosis membrane in which physical defects are removed, preventing a decrease in the salt removal rate of the reverse osmosis membrane due to defects and prolonging the use period of the reverse osmosis membrane, a manufacturing method thereof, and a reverse osmosis module including the same.

In general, the dissociated material can be separated from the solvent using various types of selective membranes. If these selective separators are described in the order of increasing the pore size, they are classified into reverse osmosis membranes, ultrafiltration membranes, and microfiltration membranes.

The use of the conventional reverse osmosis membrane is a desalination process of semi-salt water or seawater, and this desalination process provides a large amount of fresh water or pure water relatively suitable for industry, agriculture, or household use. The desalting process of semi-salt water or seawater using a reverse osmosis membrane is a process of literally filtering salts, other dissolved ions or molecules from brine. Purified water passes through the separation membrane by passing the brine through the reverse osmosis membrane and pressurizing it, whereas salts, other dissolution. Ions or molecules cannot pass through the membrane. The osmotic pressure inevitably occurs in the reverse osmosis process, and at this time, the higher the concentration of raw water, the greater the osmotic pressure, so a higher pressure is required to treat it. Thus, in order for the reverse osmosis membrane to be commercially used for desalting salt and seawater in large quantities, there are several conditions to be provided, one of which is to have a high salt removal rate. Currently, the salt removal rate of the reverse osmosis membrane to semi-saline water for commercial application is required to be at least 97%.

One of the general types of reverse osmosis membranes is a composite membrane composed of a porous support and a polyamide thin film formed on the porous support, the polyamide thin film is formed by interfacial polymerization of a polyfunctional amine and a polyfunctional acyl halide, and the porous support is In general, it is common to apply a hydrophobic polymer material on a support.

1 is a schematic diagram of a cross section of a conventional reverse osmosis membrane 100, a polymer support layer 102 is formed to obtain a high yield by forming a porous structure on a support 101 that serves as a support for the reverse osmosis membrane, A selection layer 103 is formed to increase the separation ability.

Figure 2 shows that when the reverse osmosis membrane is usually wound in a spiral wound around the porous permeated water outlet pipe (1), the reverse osmosis membranes (2, 4) having the structure as in FIG. 1 are sealed in two layers to flow into the fluid flowing into the inside and the outside. Is capable of forming an osmotic pressure gradient between fluids to separate fluids. In order to prevent a decrease in flow rate due to a decrease in the flow path due to the close contact of the separator by pressure, the internal spacers 3 of the reverse osmosis membranes 2 and 4 and the spacers 5 disposed outside the reverse osmosis membranes 2 and 4 are provided. Include.

However, in the process of packaging the reverse osmosis membrane as a module by winding the reverse osmosis membrane in a spiral wound shape as shown in FIG. 2, the selection layer (103 in FIG. 1) formed on any one side of the reverse osmosis membrane may cause fine cracks or physical defects such as grooves. In addition, this may occur due to physical force applied to the winding process and/or carelessness of an operator that may occur during work.

In addition, even if no physical defects have occurred in the manufacturing process, the reverse osmosis membrane may be compressed due to high pressure applied during operation of the reverse osmosis membrane. Spacers (3, 5 in FIG. 2) disposed on both sides of the reverse osmosis membrane usually have large pore diameters. Since a mesh sheet is used, a pressed mark may occur on the selected layer by any one mesh sheet that comes into contact with the selected layer, and if this becomes severe, the selected layer may be dent or grooved, and if it becomes more severe, it is located under the selected layer. There may be a problem of physical damage to the porous support.

The physical defects occurring in the reverse osmosis membrane selection layer and the polymer support layer as described above have a problem of lowering the salt removal rate, and can significantly reduce the use cycle of the reverse osmosis membrane, and when the reverse osmosis membrane is a reverse osmosis membrane for seawater desalination, the decrease in the salt removal rate is a fatal problem. There is an urgent need to develop a method to solve this problem easily.

The present invention was conceived to solve the above problems, and an object of the present invention is to solve the fatal problem of lowering the salt removal rate by simply removing physical defects occurring in the reverse osmosis membrane that may occur during the manufacturing process or operation of the reverse osmosis membrane. It is to provide a reverse osmosis membrane from which physical defects that can increase the use cycle are removed, a method for manufacturing the same, a reverse osmosis module including the same, and a method for manufacturing a reverse osmosis module.

In order to solve the above-described first problem, the present invention provides a reverse osmosis membrane comprising a polymer support layer formed on a support and a polyamide layer formed on the polymer support layer, wherein the polymer support layer and the polyamide layer are formed on one or more layers. It provides a reverse osmosis membrane in which physical defects, including those in which the defects are physically masked, are removed by penetration of granular polymer particles into physical defects.

According to a preferred embodiment of the present invention, the polymer particles may have a particle diameter of 0.005 to 1 μm.

According to another preferred embodiment of the present invention, the polymer particles may be a copolymer including styrene or a styrene derivative.

According to another preferred embodiment of the present invention, the copolymer may include any one or more selected from the group consisting of polystyrene and a copolymer containing an acrylic monomer, a methacrylic monomer, a butadiene monomer, and a vinylpyrrolidone monomer. have.

According to another preferred embodiment of the present invention, the copolymer may be a polyvinylpyrrolidone styrene copolymer.

According to another preferred embodiment of the present invention, the reverse osmosis membrane may have a flow rate reduction rate of 5% or less according to the following relational equation 1 under a pressure condition of 32,000 ppm sodium chloride solution at 25° C. and 800 psi.

[Relationship 1]

According to another preferred embodiment of the present invention, the reverse osmosis membrane may have a salt removal rate increase rate of 0.1% or more according to the following relational equation 2 at 25° C. and 800 psi pressure condition of 32,000 ppm sodium chloride aqueous solution.

[Relationship 2]

According to another preferred embodiment of the present invention, the polymer particles may have a particle diameter of 0.01 ~ 0.5㎛.

In addition, in order to solve the above-described problems, the present invention provides a reverse osmosis membrane comprising a polymer support layer formed on a support and a polyamide layer formed on the polymer support layer, wherein a dispersion solution containing granular polymer particles is added to the reverse osmosis membrane. Thus, it provides a method for manufacturing a reverse osmosis membrane from which physical defects are removed, including physically masking the physical defects formed on the reverse osmosis membrane through granular polymer particles.

According to a preferred embodiment of the present invention, the polymer particles may have a particle diameter of 0.005 to 1 μm.

According to another preferred embodiment of the present invention, the polymer particles may be a copolymer including styrene or a styrene derivative.

According to another preferred embodiment of the present invention, the copolymer may include any one or more selected from the group consisting of a copolymer including an acrylic monomer, a methacrylic monomer, a butadiene monomer and a vinylpyrrolidone monomer, and polystyrene. I can.

According to another preferred embodiment of the present invention, the dispersion solution may contain 3 to 35 ppm of polymer particles.

According to another preferred embodiment of the present invention, the masking may be performed by applying a pressure of 200 to 900 psi to the dispersion solution.

According to another preferred embodiment of the present invention, the masking may be performed for 20 to 70 minutes.

According to another preferred embodiment of the present invention, the dispersion solution may contain 3 to 18 ppm of polymer particles.

According to another preferred embodiment of the present invention, the polymer particles may have a particle diameter of 0.01 ~ 0.5㎛.

In addition, in order to solve the above problems, the present invention provides a reverse osmosis module in which physical defects including the reverse osmosis membrane according to the present invention are removed.

In addition, in order to solve the above-described problems, the present invention is a reverse osmosis module including a reverse osmosis membrane, by adding a dispersion solution containing granular polymer particles to the inside of the reverse osmosis module, thereby reducing the physical defects formed in the reverse osmosis membrane. It provides a method of manufacturing a reverse osmosis module in which physical defects including physically masking through polymer particles are removed.

According to a preferred embodiment of the present invention, the polymer particles may be a copolymer including styrene or a styrene derivative having a particle diameter of 0.005 to 1.0 μm.

The reverse osmosis membrane from which the physical defects of the present invention are removed removes physical micro-defects on the surface of the separation membrane that may occur in the manufacturing process of the reverse osmosis membrane and the manufacturing process of the module using the same, thereby preventing the deterioration of the salt removal rate of the reverse osmosis membrane due to the defect, and reducing the use cycle of the reverse osmosis membrane By extending it, it can exhibit remarkably excellent effects in reverse osmosis for seawater desalination among various uses for reverse osmosis membranes.

1 is a schematic cross-sectional view of a conventional reverse osmosis membrane.
2 is an exploded cross-sectional view of a conventional reverse osmosis module.
3 is an optical micrograph of a reverse osmosis membrane in which physical defects have occurred on the surface of the separation membrane.
4 is a schematic cross-sectional view of a reverse osmosis membrane from which physical defects are removed according to a preferred embodiment of the present invention.
5 is a schematic cross-sectional view of a reverse osmosis membrane from which physical defects are removed according to a preferred embodiment of the present invention.
6 is an optical micrograph of a reverse osmosis membrane from which physical defects have been removed according to a preferred embodiment of the present invention.
7 is an exploded perspective view of a reverse osmosis module according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

As described above, the conventional reverse osmosis membrane is wound in a spiral wound type and the selection layer formed on one side of the reverse osmosis membrane is finely formed due to the physical force applied to the winding process and/or the carelessness of the operator that may occur during work. Physical defects such as cracks or grooves may occur. In addition, even if no physical defects have occurred in the manufacturing process, the reverse osmosis membrane may be compressed due to high pressure applied during operation of the reverse osmosis membrane. The spacers disposed on both sides of the reverse osmosis membrane typically use mesh sheets with large pore diameters. The selected layer may be pressed by any one mesh sheet that comes into contact with the selected layer, and if this becomes severe, the selected layer may be pitted or grooved, and if it becomes more severe, physical defects may occur up to the porous support located under the selected layer. There was a problem that occurred. The physical defects occurring in the reverse osmosis membrane selective layer and the high branch support layer as described above have a problem of lowering the salt removal rate, and may significantly reduce the use cycle of the reverse osmosis membrane. Became.

Accordingly, in the present invention, in a reverse osmosis membrane comprising a polymer support layer formed on a support and a polyamide layer formed on the polymer support layer, the physical defects formed on at least one of the polymer support layer and the polyamide layer are granular. A solution to the above-described problem was sought by providing a reverse osmosis membrane from which physical defects including those in which the defects were physically masked by penetration of the polymer particles were provided. Through this, it is a reverse osmosis membrane in which physical micro-defects on the surface of the separation membrane that may occur in the manufacturing process of the reverse osmosis membrane and the manufacturing process of the module using the same are removed, preventing a decrease in the salt removal rate of the reverse osmosis membrane due to the physical defects and extending the use cycle of the reverse osmosis membrane have.

1 is a schematic diagram of a cross section of a conventional reverse osmosis membrane 100, a polymer support layer 102 is formed to obtain a high yield by forming a porous structure on a support 101 that serves as a support for the reverse osmosis membrane, A selection layer 103 is formed to increase the separation ability.

However, the selection layer 103 may cause physical defects during the manufacturing process of the reverse osmosis membrane or during reverse osmosis operation, and in more severe cases, physical defects may occur even in the polymeric support layer 102, which causes a fatal decrease in salt removal rate. Has caused. Specifically, FIG. 3 is an optical micrograph of a reverse osmosis membrane in which physical defects have occurred on the surface of the separation membrane, and it can be seen that physical defects (P, Q) have occurred on the surface of the separation membrane as shown in the above photo.

Accordingly, the present invention includes a reverse osmosis membrane in which granular polymer particles penetrate into physical defects formed on at least one of the polymer support layer and the polyamide layer to physically mask the defects.

Specifically, Figures 4 and 5 are cross-sectional schematic diagrams of a reverse osmosis membrane from which physical defects have been removed according to a preferred embodiment of the present invention. In FIG. 4, the reverse osmosis membrane is a polymer support layer 202 and a polymer support layer 202 formed on a nonwoven fabric 201. It includes a selection layer 203 formed thereon, and the granular polymer particles 211 and 212 penetrate into the grooves or cracks, which are physical defects in the selection layer 203, and physically mask the grooves and cracks. Defects generated in the selection layer 203 can be removed.

In addition, the reverse osmosis membrane in FIG. 5 includes the polymer layer 202 and the selection layer 203, and the granular polymer particle 213 penetrates the physical defect area and physically masks the reverse osmosis membrane in which cracks or grooves have occurred. Defects generated including 202 and the selection layer 203 can be removed.

Specifically, FIG. 6 is an optical micrograph of the surface of the separation membrane after the physical defects of the reverse osmosis membrane having physical defects on the separation membrane surface of FIG. 3 have been removed by granular polymer particles according to a preferred embodiment of the present invention. As can be seen through the picture, it can be seen that the physical defects (P, Q in FIG. 3) have been removed.

As can be seen from the above-described FIGS. 4 to 6, the polymer particles are forcibly inserted into the physical defects on the surface of the reverse osmosis membrane by a constant pressure and are physically masked by filling the physical defects, as described in the following manufacturing method. It is possible to prevent the deterioration of the salt removal rate.

Hereinafter, granular polymer particles that are physically masked on the defective area will be described in detail.

The polymer particles are granular particles. That is, under the conditions under which the reverse osmosis membrane is operated, specifically, it is not dissolved by seawater, water, etc., and exists in a granular state in the defective portion of the surface of the reverse osmosis membrane. The particle diameter of the polymer particles may vary depending on the size of defects that normally occur on the surface of the reverse osmosis membrane, but may be preferably 0.005 to 1 μm, and more preferably 0.01 to 0.5 μm. If the particle diameter is less than 0.005㎛, it is difficult to physically mask the cracks present on the membrane surface, so it is not possible to prevent the deterioration of the salt removal rate. Rather than physically removing the cracks, it may contaminate the reverse osmosis membrane, significantly reducing the flow rate of the reverse osmosis membrane. There is a problem. In addition, if the particle diameter exceeds 1 μm, there is a problem that the particle diameter is too large and the physical masking may not be performed properly because the particle diameter is larger than the size of a normal crack.

When the shape of the polymer particles satisfies the particle diameter range, the specific shape is not particularly limited. If the shape of the specific polymer particle is not spherical, the longest distance among the distances from one point on the surface of the particle to another point may be the particle diameter of the particle.

If the polymer particles are not dissolved in a solvent such as seawater or water used depending on the operating conditions of the reverse osmosis membrane, the polymer particles can be used without limitation, but in consideration of compatibility with the selection layer and the polymer support layer included in the reverse osmosis membrane, preferably styrene Or it may be a copolymer containing a styrene derivative. The copolymer containing the styrene or styrene derivative does not dissolve in seawater or water, so granules may exist in the state of particles in the cracked portion of the osmotic membrane, and due to the hydrophobic properties, it is compatible with the selective layer and the high branch support layer. Compared to other materials or copolymers, the physical masking effect of the defective area may be better.

Even more preferably, the copolymer containing the styrene or styrene derivative is selected from the group consisting of a copolymer containing an acrylic monomer, a methacrylic monomer, a butadiene monomer and a vinylpyrrolidone monomer, and a polystyrene. It may include any one or more. More specifically, the polystyrene has an advantage of being easy to manufacture into particles having a desired shape and particle diameter due to excellent moldability as thermoplastic, and at least one of styrene or a derivative thereof, an acrylic monomer, a methacrylic monomer, and a butadiene monomer The polymer particles including the copolymer obtained by the hybrid polymerization may have an advantage of being easy to penetrate into a part where physical defects occur due to excellent elasticity. However, in consideration of the compatibility with the selection layer and/or the polymer support layer in which the polymer particles penetrate and the persistence of not escaping from the physical defect site after penetration, the copolymer more preferably contains a vinylpyrrolidone monomer. It may be a poly(vinylpyrrolidone styrene) copolymer. The copolymer may preferably have a molecular weight of 100 to 200,000.

In the reverse osmosis membrane according to the present invention in which the above-described granular polymer particles penetrate into the physical defect area and physically mask the reverse osmosis membrane, the polymer particles do not cause contamination of the reverse osmosis membrane, so the following at 25° C. and 800 psi pressure condition of 32,000 ppm sodium chloride aqueous solution. The flow rate reduction rate according to the relational equation 1 may be 5% or less.

[Relationship 1]

As described above, even when the polymer particles are included, the reduction in the flow rate that may occur can be minimized by preventing a decrease in the salt removal rate as the flow rate reduction rate is within 5%.

In addition, according to the present invention, the reverse osmosis membrane according to the present invention in which the polymer particles penetrate into the physical defect area and is physically masked can minimize the decrease in the salt removal rate that can be increased through the selective layer having the defect area. At 25° C. and 800 psi pressure conditions, the salt removal rate increase rate according to the following relationship 2 may be 0.1% or more, more preferably, the increase rate of the salt removal rate may be 0.15%, even more preferably 0.2% or more.

[Relationship 2]

Accordingly, the increase rate of the salt removal rate of the reverse osmosis membrane in which the physical defects have occurred is 0.1% or more as the physical defects are removed, so that a decrease in the salt removal rate due to the physical defects can be prevented. In the case of the salt removal rate, when the reverse osmosis membrane is used for seawater desalination, it is one of the very important properties of the membrane, and even if the salt removal rate changes in two decimal places, physical properties can be excellent in the reverse osmosis membrane for seawater desalination. The reverse osmosis membrane from which the defects have been removed can exhibit excellent physical properties for seawater desalination among various fields.

The reverse osmosis membrane according to the present invention described above is a reverse osmosis membrane comprising a polymer support layer formed on a support and a polyamide layer formed on the polymer support layer, wherein a dispersion solution containing granular polymer particles is added to the reverse osmosis membrane. It can be manufactured by a method of manufacturing a reverse osmosis membrane in which physical defects are removed, including physically masking the formed physical defects through granular polymer particles.

The timing of physically masking through the granular polymer particles is not performed at the stage of formation of the reverse osmosis membrane, but is performed on the reverse osmosis membrane that has already been manufactured.As an example of that timing, after packaging into modules after the manufacturing process of the reverse osmosis membrane It can be carried out to ship the module in which the physical defects occurred during the manufacturing process in the test operation stage have been removed, and physical defects that may occur in the reverse osmosis membrane can be removed by performing it at regular intervals during the actual operation of the reverse osmosis module.

The description of the physical defects formed in the reverse osmosis membrane, the cause of the occurrence, and the granular polymer particles that play a physical masking role will be omitted as described above, and a method of performing physical masking on the physical defects It will be described in detail below.

According to the first embodiment of the present invention, first, a dispersion solution containing granular polymer particles is added to a reverse osmosis membrane. The method for the addition of the dispersion solution is not limited in a specific method as long as the polymer particles are treated to contact the reverse osmosis membrane, and as a preferred example, a module including a reverse osmosis membrane or a reverse osmosis membrane is used as a dispersion solution containing granular polymer particles. When immersed in or when a dispersion solution containing the granular polymer particles is added, a separate pressure is applied to insert the polymer particles into a part where physical defects occur, thereby physical masking may be performed. The method of applying the pressure may be a method of applying a negative pressure or the like after immersing the reverse osmosis membrane in a dispersion solution containing polymer particles, and pressure may be applied through other methods, but there is no limitation on a specific method.

According to the second embodiment of the present invention, a dispersion solution containing granular polymer particles is added into the reverse osmosis module.

The method for the addition of the dispersion solution is not limited in a specific method as long as the reverse osmosis membrane included in the module and the polymer particles are in contact with each other, and flows during the test evaluation of the manufactured reverse osmosis module or during actual operation of the module. Granular polymer particles may be added to raw water (for example, seawater) to contact the reverse osmosis membrane. Pressure is applied during the test evaluation of a conventional reverse osmosis membrane or during reverse osmosis operation. By using the pressure applied to the reverse osmosis module, the polymer particles can be physically masked by inserting them into the part where the physical defect occurs.

According to a preferred embodiment of the present invention, in the case of the first and second embodiments, masking may be performed by applying a pressure of 200 to 900 psi, and if the pressure is less than 200 psi, polymer particles are added to the physical defect site. Physical masking may be difficult through physical masking, and weakly masked polymer particles may come off gradually, and if the pressure exceeds 900 psi, the consolidation phenomenon due to high pressure operation may be accelerated. At this time, the masking time may preferably be performed for 20 to 70 minutes, and if the masking time is less than 20 minutes, masking may not proceed smoothly, and the effect of increasing the salt removal rate may decrease. If the masking time exceeds 70 minutes, some parts other than masking There may be a problem in that the flow rate decreases due to membrane contamination.

The solvent of the dispersion solution containing the granular polymer particles may be used without limitation as long as it does not dissolve the polymer particles, deteriorates the physical properties of the reverse osmosis membrane, and can disperse the granular polymer particles well. Non-limiting examples of this may include water.

Further, according to a preferred embodiment of the present invention, the dispersion solution may contain 3 to 35 ppm of polymer particles. If the polymer particles are contained in less than 3ppm, there may be a problem that the defect removal efficiency is deteriorated due to physical masking, and if it exceeds 35ppm, the defect removal efficiency due to physical masking is not increased anymore, so the cost of removing defects is reduced. It can rise. The content of the polymer particles in the dispersion solution may be even more preferably 3 to 18 ppm. By satisfying the above range, it is possible to manufacture a reverse osmosis membrane or a reverse osmosis module in which physical defects expressing an increase in salt removal rate of 0.1% or more while minimizing a decrease in flow rate are removed.

Meanwhile, the present invention includes a reverse osmosis module including a reverse osmosis membrane from which the physical defects according to the present invention described above are removed.

The reverse osmosis module is a module from which physical defects that may occur on the surface of the separator have been removed, and it has excellent physical properties as it prevents a decrease in the salt removal rate by minimizing a decrease in flow rate, and in particular, it can be a very suitable module for use for seawater desalination. have.

The configuration of the module may be a configuration of a conventional reverse osmosis module, and as a non-limiting example of this, the reverse osmosis membrane may be wound in a spiral shape in the reverse osmosis membrane production water inlet pipe together with a spacer for forming a flow path, and the amount of the wound membrane An end cap may be included for the shape stability of the separator wound at the end. The material, shape, and size of the spacer and the end cap may be spacers and end caps used in conventional reverse osmosis modules. The reverse osmosis membrane wound as described above may be housed in an outer case or wrapped using fiber reinforced plastics (FRP).

The material, size, and shape of the material used for the outer case or the wrapping material may also be the material, size, and shape of the material used for the outer case or wrapping material used in a conventional reverse osmosis module.

Specifically, Figure 7 is an exploded perspective view of the reverse osmosis module according to a preferred embodiment of the present invention, the reverse osmosis membrane 22 in the outer case 30 may be included in a spiral wound around the reverse osmosis membrane production water inlet pipe 20 In addition, the produced water can flow into the pipe through the hole 21 perforated in the inlet pipe 20.

The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, which should be interpreted to aid understanding of the present invention.

<Example 1>

A reverse osmosis module including a reverse osmosis membrane, which was manufactured through a conventional reverse osmosis membrane manufacturing process, was disassembled and prepared in a flat membrane state. The prepared flat membrane sample was mounted on an apparatus for evaluating a flat membrane of a cross flow method (manufactured by Woongjin Chemical). Using raw water, an aqueous solution containing 5ppm poly(vinylpyrrolidone styrene) copolymer having a particle diameter of 0.5 μm was subjected to physical masking at 225 psi pressure and 25°C for 30 minutes, and then washed with pure water at 225 psi pressure for 15 minutes. A reverse osmosis membrane from which physical defects were removed was prepared.

<Examples 2 to 4>

Prepared in the same manner as in Example 1, but not an aqueous solution containing 5 ppm of poly(vinylpyrrolidone styrene) copolymer, but an aqueous solution containing 10 ppm, 20 ppm, and 30 ppm of poly(vinylpyrrolidone styrene) copolymer respectively Was used as raw water to prepare a reverse osmosis membrane from which physical defects were removed.

<Examples 5 to 6>

Manufacturing was carried out in the same manner as in Example 1, but the pressure for physical masking was adjusted to 500 psi and 800 psi, respectively, instead of 225 psi, to prepare a reverse osmosis membrane from which physical defects were removed.

<Examples 7 to 8>

It was prepared in the same manner as in Example 1, but the time for physical masking was adjusted to 15 minutes and 60 minutes, respectively, instead of 30 minutes, to prepare a reverse osmosis membrane from which physical defects were removed.

<Examples 9 to 10>

Prepared in the same manner as in Example 1, but instead of having a particle diameter of 0.5 μm, a poly(vinylpyrrolidone styrene) copolymer having a particle diameter of 0.003 μm and 1.2 μm, respectively. A reverse osmosis membrane from which physical defects were removed was prepared by using an aqueous solution containing coalescence as raw water.

<Example 11>

It was prepared in the same manner as in Example 1, but the concentration of the poly(vinylpyrrolidone styrene) copolymer was 10 ppm and the pressure condition for physical masking was 800 psi to prepare a reverse osmosis membrane from which physical defects were removed.

<Comparative Example 1>

A reverse osmosis module including a reverse osmosis membrane, which has been manufactured through a conventional reverse osmosis membrane manufacturing process, was disassembled to prepare a flat membrane state, and the physical masking operation as in Example 1 was not performed.

<Experimental Example 1>

Stabilization at 800 psi at 25° C. for 1 hour in seawater conditions (32,000 ppm sodium chloride aqueous solution) using a cross-flow flat-film evaluation device (manufactured by Woongjin Chemical) for the separation membrane prepared in Examples and Comparative Examples, and then 30 minutes During sample collection, the amount of water produced was calculated by the weight of the permeate, and the salt removal rate was measured using a conductivity meter (HACH), and the results are shown in Table 1 below.

<Experimental Example 2>

The reverse osmosis membranes prepared in Example 11 and Comparative Example 1 were manufactured with an 8-inch reverse osmosis module, and physical properties were evaluated using an 8-inch module evaluation device (manufactured by Woongjin Chemical). At this time, the physical property evaluation is a module evaluation device of a cross-flow method. After stabilizing for 30 minutes at 800psi, 25℃, and 8% recovery rate under seawater conditions (32,000ppm sodium chloride aqueous solution), a sample is collected and the quantity of production is measured with an electronic flow meter, and a conductivity meter The salt removal rate was measured using.

In addition, it was confirmed the rate of change of the flow rate and salt removal rate for Example 11 compared to Comparative Example 1.

Furthermore, a dye solution was used to apply a pressure of 225 psi on the module, and the effect of compensating the defects of the Example compared to the Comparative Example was photographed with an optical microscope.

The results for the above physical property evaluation are shown in Table 2 below, and photographs are shown in FIGS. 3 and 6.

Flow (GFD) Salt removal rate (%) Flow rate reduction (%) Salt removal rate increase (%) Example 1 21.62 99.40 2.71 0.19 Example 2 21.39 99.43 3.74 0.23 Example 3 20.98 99.42 5.60 0.21 Example 4 21.50 99.35 3.24 0.14 Example 5 21.91 99.51 1.42 0.30 Example 6 23.16 99.51 -4.22 0.31 Example 7 21.27 99.32 4.30 0.11 Example 8 21.94 99.39 1.27 0.18 Example 9 18.54 99.42 16.56 0.21 Example 10 22.08 99.30 0.63 0.09 Example 11 21.27 99.55 4.28 0.34 Comparative Example 1 22.22 99.21 - -

Specifically, as can be seen from Table 1 above, it can be seen that the flow rate decreased as a whole in the case of physical masking, but the salt removal rate increased by 0.1% or more, and in the case of the reverse osmosis membrane for seawater desalination, the salt removal rate change of two decimal places Also, it can be seen that physical properties are remarkably improved by physically masking the granular polymer particles.

However, it can be seen that there is no more synergistic effect in the increase rate of the salt removal rate in Examples 3 (20 ppm) and Example 4 (30 ppm) in which the concentration of the polymer particles is higher than that of Example 2, which is 10 ppm. In the case of, it can be seen that the decrease in flow rate is rather large.

In addition, in the case of Example 6 in which the pressure was applied at 800 psi under the pressure condition for physical masking, the salt removal rate increase rate was 0.3% or more, and the flow rate decrease rate was less than 5%, indicating remarkably excellent physical properties.

In addition, in the case of Example 7 in which the pressure was applied for 15 minutes, the increase rate of the salt removal rate was somewhat low.

In addition, in the case of Example 9 in which the particle diameter of the polymer particles was 0.003 μm, the flow rate reduction rate was largely 10% or more, and it was confirmed that the masking effect was not large in the case of Example 10 of 1.2 μm.

In the case of Example 11, in which 0.5um-sized polymer particles, which are the best conditions in Examples 1 to 10, were treated at 800 psi for 30 minutes at a concentration of 10 ppm, the rate of decrease in the flow rate was less than 5%, while the rate of increase in the salt removal rate was highest 0.34%. Confirmed as.

Flow (GPD) Salt removal rate (%) Flow rate reduction (%) Salt removal rate change rate (%) Example 11 8,513 99.83 4.53 0.15 Comparative Example 1 8,917 99.69 - -

Specifically, as shown in Table 2, the rate of change in the flow rate in the reverse osmosis module was 5% or less, and the rate of change in the salt removal rate was 0.15%, indicating that physical defects were removed.

The effect of increasing the salt removal rate varies depending on the state of defects of individual separators or individual modules. Therefore, when the number of defects is small, the synergistic effect is relatively low, and when there are many defects, the synergistic effect may be relatively large. In other words, it is necessary to understand the effect of development as a relative concept rather than an absolute value of the increase rate of the salt removal rate due to defect masking.

Claims (20)

delete delete delete delete delete delete delete delete In a reverse osmosis membrane comprising a polymer support layer formed on a support and a polyamide layer formed on the polymer support layer,
Physical defects formed on the reverse osmosis membrane by adding a dispersion solution containing 3 to 18 ppm of polymer particles, which is a granular poly(vinylpyrrolidone styrene) copolymer with a particle diameter of 0.01 to 1 μm, at a pressure of 200 to 900 psi to the reverse osmosis membrane. The method of manufacturing a reverse osmosis membrane in which physical defects are removed by physically masking through the granular poly(vinylpyrrolidone styrene) copolymer polymer particles. delete delete delete delete delete The method of claim 9,
The method of manufacturing a reverse osmosis membrane from which physical defects are removed, wherein the masking is performed for 20 to 70 minutes. delete The method of claim 9,
The polymer particle has a particle diameter of 0.01 ~ 0.5㎛, characterized in that the physical defect is removed reverse osmosis membrane manufacturing method. delete In the reverse osmosis module comprising a reverse osmosis membrane,
A dispersion solution containing 3 to 18 ppm of polymer particles, which is a granular poly(vinylpyrrolidone styrene) copolymer having a particle diameter of 0.01 to 1 μm, was added into the reverse osmosis module at a pressure of 200 to 900 psi to form a reverse osmosis membrane. A method of manufacturing a reverse osmosis module in which physical defects are removed by physically masking a physical defect portion through the granular poly(vinylpyrrolidone styrene) copolymer polymer particles. delete

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