KR20150079213A - Reverse-osmosis membrane having excellent pressure-resistant and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a reverse osmosis membrane with an excellent pressure resistance and a manufacturing method thereof and more particularly, to a reverse osmosis membrane with an excellent pressure resistance wherein the reverse osmosis membrane has an appropriate permeation flow rate and salt rejection rate, compared with a conventional reverse osmosis membrane and at the same time shows an excellent pressure resistance in a high-temperature and high-pressure environment, thus minimizing a reduction of a flow rate. The invention also relates to a manufacturing method thereof.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse osmosis membrane having excellent pressure resistance and a method of manufacturing the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse osmosis membrane having excellent pressure resistance and a method for producing the reverse osmosis membrane, and more particularly to a reverse osmosis membrane having excellent permeation flow rate and salt removal ratio as compared with conventional reverse osmosis membranes, A reverse osmosis membrane having excellent pressure resistance and a method for producing the same.

Generally, the dissociated material can be separated from the solvent using various types of selective membranes. These selective membranes are classified into reverse osmosis membranes, ultrafiltration membranes and microfiltration membranes in order of increasing pore size.

Conventional use of reverse osmosis membranes is a desalination process of semi-saline or seawater, and this desalination process allows a large amount of fresh or pure water that is relatively suitable for industrial, agricultural, or domestic use. The desalination process of semi-brine or seawater using reverse osmosis membrane is a process of literally filtering salts, other dissolved ions or molecules from the brine. By passing the brine through the reverse osmosis membrane, the purified water passes through the membrane, Ions or molecules can not pass through the separator. The osmotic pressure is inevitably generated in the reverse osmosis process, and the higher the concentration of the raw water, the higher the osmotic pressure. Therefore, in order for the reverse osmosis membrane to be commercially used for dechlorinating a large amount of saline and seawater, there are some conditions to be equipped, one of which has a high salt removal rate. At present, the salt removal rate of the reverse osmosis membrane for semi-saline water for commercial application is at least 97%.

As a result, studies on reverse osmosis membranes have been focused on, with high salt removal rates, and further studies for improving the flow rate and chemical resistance have been continued.

As a part of this effort, the most studied part is focused on the selective layer that plays a crucial role for salt exclusion, and as a result, it is now common to use a polyamide layer as a selective layer for salt exclusion. 1 is a cross-sectional view of a conventional reverse osmosis membrane. A polymer supporting layer 102 is formed on a support 101 and a polyamide layer 103 is formed as a selective layer on the polymer supporting layer 103. The polyamide layer 103 is generally formed by interfacial polymerization of a polyfunctional amine and a polyfunctional acyl halide.

On the other hand, in order to increase the salt removal rate, conventionally, the salt removal rate has been increased by focusing on the polyamide layer through a method such as modifying the surface of the polyamide layer. However, the inventors of the present invention have been studying to obtain a better salt removal rate and flow rate through a polymer support layer rather than a polyamide layer. In the course of the research, it has been found that by incorporating carbon nanotubes in a polymer support layer, Korean Patent Application No. 2012-0141506 by the present inventor discloses a reverse osmosis membrane containing carbon nanotubes in a polymer support layer.

However, the reverse osmosis membrane of Korean Patent Application No. 2012-0141506 by the present inventors has a problem that the pressure resistance performance is poor and the flow rate after the long-time high pressure operation is remarkably lowered even though the salt removal rate and the flow rate can be obtained better than the conventional ones.

The reverse osmosis membrane must withstand the pressure above the osmotic pressure which is gradient between the two fluids having different concentrations through the osmotic membrane and the reverse osmosis membrane which can not withstand the pressure is poor in durability and the use period of the reverse osmosis membrane is significantly decreased, Can not be obtained.

As a result, it is urgently required to study reverse osmosis membranes which have an appropriate flow rate and salt removal ratio as compared with conventional reverse osmosis membranes, and have a remarkably improved pressure resistance and can be operated under high-pressure environmental conditions.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a reverse osmosis membrane capable of operating in a high-pressure environment and preventing a decrease in flow rate, And a reverse osmosis membrane having excellent pressure resistance that can significantly improve the service life even at a high pressure, a method for manufacturing the reverse osmosis membrane, and a reverse osmosis module including the reverse osmosis membrane.

In order to solve the above-described problems, the present invention provides a method of manufacturing a polymer electrolyte fuel cell, comprising the steps of: (1) treating a polymer solution containing inorganic particles having a particle diameter of 10 to 55 mu m on at least one surface of a support to form a polymer support layer; And (2) adding an aqueous solution containing a polyfunctional amine to the polymer support layer and then contacting the polymer solution with an organic solution containing a polyfunctional acid halide compound to form a polyamide layer. to provide.

According to a preferred embodiment of the present invention, the polymer solution of step (1) may be selected from the group consisting of N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylsulfoxide (DMSO) DMAc) may be included.

According to another preferred embodiment of the present invention, the polymer solution of the step (1) may be at least one selected from the group consisting of a polysulfone polymer, a polyamide polymer, a polyimide polymer, a polyester polymer, an olefin polymer, polyvinylidene fluoride , A polybenzimidazole polymer, and a polyacrylonitrile. ≪ IMAGE >

According to another preferred embodiment of the present invention, the particle size of the inorganic particles in the step (1) may be 10 to 30 탆.

According to another preferred embodiment of the present invention, the inorganic particles in the step (1) may be added in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the polymer material contained in the polymer solution.

According to another preferred embodiment of the present invention, the inorganic particles are spherical in shape and may include at least one selected from the group consisting of silica, glass, glass modified by surface modification with a hydrophilic group, and titanium dioxide.

According to another preferred embodiment of the present invention, the inorganic particles in step (1) may be included in an amount of 0.04 to 0.35 parts by weight based on 100 parts by weight of the polymer material contained in the polymer solution.

According to another preferred embodiment of the present invention, the inorganic particles are spherical in shape and may include at least one of a glass and a glass surface-modified with a hydrophilic group.

Further, in order to solve the above-mentioned problems, A polymeric support layer formed on at least one surface of the support and including inorganic particles having a particle diameter of 10 to 55 mu m; And a polyamide layer formed on the polymer support layer. The present invention also provides a reverse osmosis membrane having excellent pressure resistance.

According to a preferred embodiment of the present invention, the support may be a fabric.

According to another preferred embodiment of the present invention, the thickness of the polymer supporting layer may be 30 to 300 mu m.

According to another preferred embodiment of the present invention, the polymer support layer may be formed of a polymer such as a polysulfone polymer, a polyamide polymer, a polyimide polymer, a polyester polymer, an olefin polymer, polyvinylidene fluoride, A polymer, and a polyacrylonitrile. ≪ IMAGE >

According to another preferred embodiment of the present invention, the particle size of the inorganic particles may be 10 to 30 탆.

According to another preferred embodiment of the present invention, the inorganic particles may be included in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the polymer material contained in the polymer support layer.

According to another preferred embodiment of the present invention, the inorganic particles are spherical in shape and may include at least one selected from the group consisting of silica, glass, glass modified with a hydrophilic group, and titanium dioxide.

According to another preferred embodiment of the present invention, the inorganic particles may be contained in an amount of 0.04 to 0.35 parts by weight based on 100 parts by weight of the polymer support layer.

According to another preferred embodiment of the present invention, the inorganic particles are spherical in shape and may include at least one of a glass and a glass surface-modified with a hydrophilic group.

According to another preferred embodiment of the present invention, the reverse osmosis membrane may have a permeation flow rate of 19 GFD or more and a salt removal rate of 99% or more after being operated for 2 hours at 40 ° C and 853 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride.

According to another preferred embodiment of the present invention, the reverse osmosis membrane may have a flow rate reduction rate of 6.0% or less according to the following formula 1 after 2 hours' operation at 40 ° C and 853 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride.

[Relation 1]

* Flow 1 is the permeate flow rate at 25 ° C and 800 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride.

* Flow 2 is the permeate flow rate after 2 hours of operation at 40 ° C and 853 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride.

The present invention also provides a reverse osmosis module including a reverse osmosis membrane according to the present invention in order to solve the above problems.

The reverse osmosis membrane of the present invention has an appropriate permeation flow rate and salt removal ratio as compared with a conventional reverse osmosis membrane and has a remarkably excellent pressure resistance even in a high temperature and high pressure environment so that the flow rate reduction can be minimized and the service life can be extended.

1 is a schematic cross-sectional view of a conventional reverse osmosis membrane.
2 is a schematic cross-sectional view of a reverse osmosis membrane according to a preferred embodiment of the present invention.
3 is an exploded perspective view of a reverse osmosis module according to a preferred embodiment of the present invention.

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

As described above, the research direction of the conventional reverse osmosis membrane is focused on improving the salt removal rate, stain resistance, chemical resistance, and water permeation through hydrophilization modification of the polyamide layer as a selective layer. And particularly, the above-mentioned properties are focused only on the reverse osmosis membrane. In particular, the conventional reverse osmosis membrane has a problem that the flow rate is remarkably reduced at the time of operation in a high-pressure environment, which limits operating conditions. In addition, the insufficient pressure resistance has a problem that the durability of the membrane due to the operation is lowered under the condition of high pressure, thereby remarkably shortening the use period.

(1) forming a polymer support layer on at least one surface of a support by treating a polymer solution containing inorganic particles having a particle diameter of 10 to 55 탆; And

(2) adding an aqueous solution containing a polyfunctional amine to the polymer support layer and then contacting the polymer solution with an organic solution containing a polyfunctional acid halide compound to form a polyamide layer; Thereby solving the above-mentioned problem. Accordingly, it is possible to provide a reverse osmosis membrane having excellent permeation flow rate and salt removal ratio as compared with a conventional reverse osmosis membrane and having excellent pressure resistance even in a high temperature and high pressure environment, minimizing the flow rate reduction and having an extended service life, .

In the step (1) of the present invention, a step of forming a polymer support layer by treating a polymer solution containing inorganic particles having a particle diameter of 10 to 55 μm on a support is carried out.

First, the support will be described in detail.

The support is not particularly limited as long as it is a support for a reverse osmosis membrane, but may be a fabric. Specifically, the fabric means a fabric, a knitted fabric, or a nonwoven fabric. The fabric has a vertical and horizontal orientation as it is woven with warp and weft. The knitted fabric may have a specific directionality depending on the knitting method, Direction. ≪ / RTI > Further, the nonwoven fabric has no longitudinal and transverse directions unlike the above-mentioned fabric or knitted fabric.

 When the fabric is a fabric, physical properties such as porosity, pore size, strength, permeability, etc. of the target support can be controlled by controlling the type of fiber forming the fiber, the fineness, the density of the fiber, and the texture of the fabric.

In addition, when the fabric is a knitted fabric, properties such as porosity, pore size, strength, and permeability of the desired support can be controlled by controlling the type of fibers, fineness, texture of the knitted fabric, gauges, cuts and the like contained in the knitted fabric.

In addition, when the fabric is a nonwoven fabric, properties such as porosity, pore size, strength, permeability, etc. of the desired support can be controlled by controlling the type, fineness, fiber length, basis weight, density and the like of the fibers included in the nonwoven fabric.

The material of the support may serve as a support for the membrane, and may be used without limitation as long as it is used for a support of a conventional separation membrane. By way of non-limiting example, synthetic fibers selected from the group consisting of polyester, polypropylene, nylon and polyethylene; Or natural fibers including cellulosic fibers; Can be used.

The support preferably has an average pore size of 1 to 100 mu m, more preferably 1 to 50 mu m. When the average pore size is less than 1 탆, there is a problem of lowering the flow rate, and there may be a problem such as generating differential pressure of the filter. When the average pore size exceeds 100 탆, the mechanical strength of the support is lowered, There is a problem that can not be done.

The support of the present invention preferably has a thickness of 20 to 150 mu m, and if it is less than 20 mu m, the strength and supporting ability of the entire film are insufficient, and if it exceeds 150 mu m, the flow rate may be decreased.

Next, the polymer solution to be treated on at least one side of the support will be described.

The solvent contained in the polymer solution is not particularly limited as long as it can dissolve the polymer material contained in the polymer solution uniformly without forming precipitates, but more preferably N-methyl-2-pyrrolidone (NMP) , Dimethylformamide (DMF), dimethylsulfoxide (DMSO), or dimethylacetamide (DMAc), or the like.

If the temperature is lower than 20 ° C, the polymer may not be dissolved and the membrane may not be produced. If the temperature is higher than 90 ° C, the viscosity of the polymer solution may become too thin, and thus the membrane may be difficult to produce .

The polymeric material may be a polymeric material contained in a conventional reverse osmosis membrane polymeric support layer. In consideration of mechanical strength, it is preferable to use a polymeric material having a weight average molecular weight in the range of 65,000 to 150,000. As a preferable example, polysulfone- A polyimide-based polymer, a polyester-based polymer, an olefin-based polymer, polyvinylidene fluoride, a polybenzimidazole polymer, and polyacrylonitrile.

The polymer solution may preferably contain 7 to 35% by weight of the polymer material. If the content of the polymeric substance is less than 7% by weight, the strength is lowered and the solution viscosity is low. Thus, the film is difficult to manufacture and has a problem. When it exceeds 35% by weight, the concentration of the polymer solution is too high.

The polymer support layer used in the reverse osmosis membrane of the present invention is a general microporous support layer and is not particularly limited in its kind but is generally large enough to permit permeation of permeated water and large enough to interfere with the ultra- Should not. At this time, the pore size of the porous support layer is preferably from 1 to 500 nm, and when the thickness exceeds 500 nm, the ultra thin film may sink into the pore size after the formation of the thin film, so that it may be difficult to achieve the required flat sheet structure.

On the other hand, the polymer solution includes inorganic particles having a particle diameter of 10 to 55 mu m.

The present inventors have found that by providing a polymer support layer by incorporating carbon nanotubes in a polymer solution to obtain a salt removal rate and a flow rate that are better than those of the prior art, the friction resistance of water molecules due to the hydrophobic and smooth materials of the inner wall surface of the carbon nanotubes itself And the water molecules move in a chain shape by the hydrogen bonding force between water molecules close to each other, thereby increasing the permeation flow rate compared to the conventional reverse osmosis membrane. However, such a reverse osmosis membrane has a problem that the flow rate is considerably lowered under high-pressure operating conditions and is limited in use under high-pressure conditions.

The inventors of the present invention have found that by including inorganic particles having a particle diameter of 10 to 55 탆 in a polymer solution, it is possible to obtain an appropriate flow rate and salt removal ratio as compared with the past, and at the same time, Could. If the particle size of the inorganic particles is less than 10 탆, the permeation flow rate of the polymer scaffold and the permeate flow rate of the reverse osmosis membrane may be improved, but the flow rate may remarkably decrease at a high pressure operating condition and the effect of improving the pressure resistance may be insignificant. If the particle size exceeds 55 μm, the flow rate may be significantly decreased under the operating conditions of the permeation flow rate and the high pressure of the polymer scaffold, and the salt removal rate may be decreased due to a defect on the surface of the support layer. The inorganic particles may have a particle diameter of 10 to 30 탆, more preferably 20 to 30 탆, in order to exhibit a better permeation flow rate and a salt removal rate in an environment of high pressure and high temperature.

The inorganic particles having a particle size range as described above may preferably be spherical in shape so that the dispersibility of the polymer particles in the polymer solution can be increased and the particles can be evenly distributed in the prepared polymer support layer, Lt; / RTI > Specific examples of the inorganic particles may include at least one selected from the group consisting of silica, glass, glass surface-modified with a hydrophilic group, titanium dioxide, aluminum oxide (Al ₂ O ₃ ), and calcium carbonate. More preferably, it may include at least one selected from the group consisting of silica, glass, glass modified by surface modification with a hydrophilic group, and titanium dioxide. In order to secure a better flow rate under high temperature and high pressure conditions, And a glass surface-modified with a hydrophilic group.

The inorganic particles may be contained in an amount of 0.01 to 0.5 parts by weight, and more preferably 0.04 to 0.35 parts by weight, based on 100 parts by weight of the polymer material contained in the polymer solution. If the inorganic particles are contained in an amount of less than 0.01 part by weight, the degree of improvement of the pressure resistance may be insufficient and the flow rate obtained under high pressure conditions may be deteriorated. If the inorganic particles are contained in an amount exceeding 0.5 parts by weight, There may be a problem that the permeation flow rate decreases.

When the inorganic particles are mixed into the polymer solution, they can be further dispersed for more uniform dispersion after the primary dispersion by stirring for 4 to 8 hours for even dispersion, and the secondary dispersion is preferably a bass type Using an ultrasonic washing machine of 70 to 90% for 50 minutes to 2 hours. Thereafter, the polymer solution containing the dispersed inorganic particles may be further subjected to a step of removing bubbles contained in the polymer solution, wherein the removing method may preferably be performed under a vacuum condition for 20 minutes to 1 hour.

The polymer solution in which the inorganic particles are dispersed as described above can be treated on at least one surface of the support, and preferably the polymer support layer can be formed through the coating method. When the polymer solution is coated, Thickness. Thereafter, the support on which the polymer solution is applied for phase transition is immersed in distilled water, preferably at 20 to 30 ° C, to form pores, and the remaining solvent and water are substituted by sufficient water washing to prepare a polymer support layer formed on the support . The method for forming the above-described polymeric support layer is not limited to a specific method, but the specific method may be modified according to the purpose.

Next, in step (2), an aqueous solution containing a polyfunctional amine is added to the polymer support layer prepared in the step (1), and then the polymer solution is contacted with an organic solution containing a polyfunctional acid halide compound to form a polyamide layer .

Specifically, the polyfunctional amine may be a polyamine having two or three amine functional groups per monomer, and may include a primary amine or a secondary amine. As the polyamines, aromatic primary diamine is used as the metaphenylenediamine, paraphenylenediamine, orthophenyldiamine and the substituent. As another example, aliphatic primary diamine and cycloaliphatic primary diamine such as cyclohexenediamine , Cycloaliphatic secondary amines such as piperazine, and aromatic secondary amines. More preferably, the polyfunctional amine is selected from the group consisting of metaphenylenediamine, and the concentration thereof is preferably in the form of an aqueous solution containing 0.5 to 10 wt% of metaphenylenediamine, more preferably 1 to 4 wt% % May be contained.

Upon formation of the polyamide layer of the present invention, the polyfunctional amine-containing aqueous solution may be applied onto the polymer support layer for 0.1 to 10 minutes, more preferably for 0.5 to 1 minute.

The material which reacts with the polyfunctional amine used in forming the polyamide layer of the present invention is a polyfunctional acid halide, that is, a polyfunctional acyl halide. Preferably, it may be used alone or in a mixed form of trimesoyl chloride, isophthaloyl chloride, 5-methoxy-1,3-isophthaloyl chloride, terephthaloyl chloride and the like. At this time, the use of the mixed form is most preferable in terms of the salt removal rate. The polyfunctional acyl halide may be dissolved in an aliphatic hydrocarbon solvent in an amount of 0.01 to 2% by weight. The aliphatic hydrocarbon solvent may be a mixture of n-alkanes having 5 to 12 carbon atoms and structural isomers of saturated or unsaturated hydrocarbons having 8 carbon atoms It is preferable to use a cyclic hydrocarbon having 5 to 7 carbon atoms. The polyfunctional acyl halide-containing solution preferably dissolves 0.01 to 2% by weight, more preferably 0.05 to 0.3% by weight, of the polyfunctional acyl halide in the aliphatic hydrocarbon solvent. In forming the polyamide layer of the present invention, the polyfunctional acid halide compound may be applied to the membrane treated with the aqueous solution containing the polyfunctional amine for 0.1 to 10 minutes, more preferably for 0.5 to 1 minute.

The reverse osmosis membrane produced by the above production method comprises a support, a polymer support layer including inorganic particles having a particle diameter of 10 to 55 탆 formed on at least one side of the support, and a polyamide layer formed on the polymer support layer.

2 is a cross-sectional schematic diagram of a reverse osmosis membrane according to one preferred embodiment of the present invention. The polymer support layer 202 includes inorganic particles 210 formed on at least one side of a support 201, and the polymer support layer 202, Lt; RTI ID = 0.0 > 203 < / RTI >

The support 201 will be described first.

The support 201 is not particularly limited as long as it serves as a support for a reverse osmosis membrane, but may be a fabric. Specifically, the fabric means a fabric, a knitted fabric, or a nonwoven fabric. The fabric has a vertical and horizontal orientation as it is woven with warp and weft. The knitted fabric may have a specific directionality depending on the knitting method, Direction. ≪ / RTI > Further, the nonwoven fabric has no longitudinal and transverse directions unlike the above-mentioned fabric or knitted fabric.

 When the fabric is a fabric, physical properties such as porosity, pore size, strength, permeability, etc. of the target support can be controlled by controlling the type of fiber forming the fiber, the fineness, the density of the fiber, and the texture of the fabric.

In addition, when the fabric is a knitted fabric, physical properties such as porosity, pore size, strength, and permeability of the desired support can be controlled by controlling the type of fibers, fineness, texture of the knitted fabric, gauges, cuts and the like contained in the knitted fabric.

When the fabric is a nonwoven fabric, physical properties such as porosity, pore size, strength, permeability and the like of the desired support can be controlled by controlling the type, fineness, fiber length, basis weight, density and the like of the fibers contained in the nonwoven fabric.

The material of the support may serve as a support for the membrane, and may be used without limitation as long as it is used for a support of a conventional separation membrane. By way of non-limiting example, synthetic fibers selected from the group consisting of polyester, polypropylene, nylon and polyethylene; Or a natural fiber including a cellulose system can be used.

The support preferably has an average pore size of 1 to 100 mu m, more preferably 1 to 50 mu m. When the average pore size is less than 1 탆, there is a problem of lowering the flow rate, and there may be a problem such as generating differential pressure of the filter. When the average pore size exceeds 100 탆, the mechanical strength of the support is lowered, There is a problem that can not be done.

The support of the present invention preferably has a thickness of 20 to 150 mu m, and if it is less than 20 mu m, the strength and supporting ability of the entire film are insufficient, and if it exceeds 150 mu m, the flow rate may be decreased.

Next, the polymer supporting layer 202 including the inorganic particles 210 having a particle diameter of 10 to 55 μm formed on at least one surface of the support will be described.

The polymer support layer 202 is not particularly limited as long as it can form a reverse osmosis membrane. However, in consideration of mechanical strength, it is preferable to use a polymer support layer having a weight average molecular weight in the range of 65,000 to 150,000, Based polymers such as polyamide-based polymers, polyimide-based polymers, polyester-based polymers, and polypropylene; polysulfone-based polymers such as polybenzimidazole polymers, polyvinylidene fluoride or polyacrylonitrile; Alone or in a mixed form.

The thickness of the polymer support layer may be in the range of 30 to 300 占 퐉. If the thickness is less than 30 占 퐉, there may be a problem of lowering the flow rate and durability due to compaction, and if it is more than 300 占 퐉, . The pore size of the polymer support layer is preferably 1 to 500 nm.

The polymeric support layer 202 according to the present invention includes inorganic particles having a particle diameter of 10 to 55 mu m.

Since the polymer support layer 202 contains the inorganic particles 210 having a particle diameter of 10 to 55 탆, it is possible to obtain an appropriate flow rate and salt removal ratio as compared with a conventional reverse osmosis membrane, and at the same time to significantly improve the pressure resistance, Reduction can be minimized. If the particle size of the inorganic particles is less than 10 탆, the permeation flow rate of the polymer scaffold and the permeate flow rate of the reverse osmosis membrane may be improved, but the flow rate may remarkably decrease at a high pressure operating condition and the effect of improving the pressure resistance may be insignificant. If the particle size exceeds 55 μm, the flow rate may be significantly decreased under the operating conditions of the permeation flow rate and the high pressure of the polymer scaffold, and the salt removal rate may be decreased due to a defect on the surface of the support layer. The inorganic particles may have a particle diameter of 10 to 30 탆, more preferably 20 to 30 탆, in order to exhibit a better permeation flow rate and a salt removal rate in an environment of high pressure and high temperature.

The inorganic particles 210 having a particle size range as described above may preferably be spherical in shape so that the dispersibility of the inorganic particles 210 in the polymer solution can be increased and evenly distributed in the prepared polymer support layer, It is possible to have better pressure resistance. Specific examples of the inorganic particles may include at least one selected from the group consisting of silica, glass, glass surface-modified with a hydrophilic group, titanium dioxide, aluminum oxide (Al ₂ O ₃ ), and calcium carbonate. More preferably, it may include at least one selected from the group consisting of silica, glass, glass modified by surface modification with a hydrophilic group, and titanium dioxide. In order to secure a better flow rate under high temperature and high pressure conditions, And a glass surface-modified with a hydrophilic group.

The inorganic particles 210 may be included in an amount of 0.01 to 0.5 parts by weight, and more preferably 0.04 to 0.35 parts by weight, based on 100 parts by weight of the polymer material contained in the polymer support layer. If the inorganic particles are contained in an amount of less than 0.01 part by weight, the degree of improvement of the pressure resistance may be insufficient and the flow rate obtained under high pressure conditions may be deteriorated. If the inorganic particles are contained in an amount exceeding 0.5 parts by weight, There may be a problem that the permeation flow rate decreases.

Next, the polyamide layer 203 formed on the polymer support layer 202 including the inorganic particles 210 will be described.

The polyamide layer 203 serves as a selective layer for salt removal and the like, and may be a polyamide layer included in a conventional reverse osmosis membrane. The polyamide layer 203 may be formed by interfacial polymerization after being immersed in an aqueous solution containing a polyfunctional amine and then contacting an organic solution containing a polyfunctional acid halide compound. If the thickness of the polyamide layer 203 is less than 0.1 탆, the salt removing ability of the polyamide layer 203 can not be reduced. If the thickness is more than 1 탆, the thickness of the selective layer is too thick There is a problem that the flow rate is lowered.

As described above, since the reverse osmosis membrane according to the present invention can obtain an improved flow rate and an excellent salt removal rate under high temperature and high pressure operation conditions, it can be operated at a pressure of 853 psi at 40 ° C for 2 hours in an aqueous solution containing 32,000 ppm sodium chloride The permeate flow rate may be 17 GFD or more, and the salt removal rate may be 99% or more, and more preferably, the permeate flow rate may be 19 GFD or more.

In addition, the reverse osmosis membrane according to the present invention has excellent pressure resistance under high temperature and high pressure operating conditions and has a flow rate reduction ratio of 6% or less under high pressure and high temperature conditions in comparison with a flow rate under a non-high pressure condition. Concretely, the flow rate reduction rate according to the following relational expression 1 is less than 6% after 2 hours of operation at 40 ° C and 853 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride.

[Relation 1]

At this time, the flow rate 1 is a permeate flow rate at 25 ° C and 800 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride, and the flow rate 2 is a permeate flow rate after 2 hours operation at 40 ° C and 853 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride .

Meanwhile, the present invention includes a reverse osmosis module including a reverse osmosis membrane according to the present invention.

As a non-limiting example, the reverse osmosis membrane may be wound into a porous permeable effluent tube in a spiral wound with spacers for flow path formation, and the amount of wound membrane And an end cap for shape stability of the membrane wound on the end. The material, shape, and size of the spacer and end cap can be spacers and end caps used in conventional reverse osmosis modules. The reverse osmosis membrane thus wound may be housed in an outer case, and the material, size, and shape of the outer case may be the material, size, and shape of the outer case used in a conventional reverse osmosis module.

3 is an exploded perspective view of a reverse osmosis module according to a preferred embodiment of the present invention in which the reverse osmosis membrane 20 is wrapped around the porous permeation and outflow tube 21 in a bobbin form in the outer case 30 .

The present invention will now be described more specifically with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

≪ Example 1 >

First, 19% by weight of polysulfone was added to 81% by weight of dimethylacetamide (DMAc) slowly while stirring at 60 DEG C for 6 hours to prepare a polysulfone solution. 0.056 parts by weight of a spherical glass bead having a particle diameter of 40 to 50 占 퐉 was added to the polysulfone solution per 100 parts by weight of the polysulfone, and the mixture was stirred for 6 hours and physically dispersed first, and then dispersed in a bath type ultrasonic cleaner % Strength for 1 hour. After that, bubbles in the polysulfone solution were removed by vacuum for 30 minutes.

Thereafter, the polysulfone solution was cast on a polyester nonwoven fabric (100 mu m) to a thickness of about 50 mu m, the membrane was immediately dipped in distilled water at 25 DEG C to make a phase change, and then the nonwoven fabric-reinforced polysulfone substrate was sufficiently washed with water, After replacing the solvent and water, the solution was stored in pure water at room temperature to prepare a polymer support layer formed on the nonwoven fabric.

Thereafter, the polymer support layer formed on the nonwoven fabric containing the inorganic particles was immersed in an aqueous solution containing m-phenylenediamine at a concentration of 3.0% by weight for 1 minute, and then the water layer on the surface was removed by a pressing method. Thereafter, the mixture was immersed in an organic solution containing 0.07% by weight of trimethoyl chloride and 0.1% by weight of isophthaloyl chloride for one minute to perform interfacial polymerization, and then naturally dried at room temperature (25 ° C) for 1 minute and 30 seconds to form a polyamide layer A reverse osmosis membrane having a total thickness of 150 μm was prepared.

≪ Examples 2 to 6 >

Except that the spherical glass beads were used in an amount of 0.14, 0.28, 0.42, 0.56, and 1.1 parts by weight, respectively, instead of 0.056 parts by weight, to prepare a reverse osmosis membrane.

≪ Examples 7 to 9 >

Except that spherical glass beads were prepared in the same manner as in Example 1 except that glass beads having a particle size of 30 to 40 탆, 20 to 30 탆 and 10 to 20 탆 were used instead of 40 to 50 탆, .

≪ Examples 10 to 11 &

Except that spherical silica and spherical titanium dioxide were used in place of spherical glass beads to prepare a reverse osmosis membrane.

≪ Comparative Example 1 &

The reverse osmosis membrane was prepared in the same manner as in Example 1 except that the glass beads were not included in the polysulfone solution.

≪ Comparative Example 2 &

(MWCNT) having a length of 0.2 μm communicated at both ends instead of spherical glass beads was prepared in the polysulfone solution to prepare a reverse osmosis membrane.

≪ Comparative Examples 3 and 4 &

Except that spherical glass beads having particle diameters of 1 to 10 μm and 60 to 70 μm were used instead of 40 to 50 μm, respectively, to prepare a reverse osmosis membrane.

<Experimental Example 1>

The following properties were measured for the performance evaluation of the polymer support layer itself formed on the nonwoven fabric and the nonwoven fabric prepared before the formation of the polyamide layer during the manufacturing process through the above Examples and Comparative Examples.

1. Permeation flow (GFD, gallon per feet ² · day)

The permeation flow rate was measured using a flat-film evaluation machine (manufactured by Woongjin Chemical Co., Ltd.) under the pressure of 1 kg · f / cm 2 with deionized water at 25 ° C.

2. Polyethylene Oxide Removal Rate (%)

The removal rate was measured using 2000 ppm of polyethylene oxide (weight average molecular weight of 100,000) under a pressure of 1 kg · f / cm 2 at 25 ° C.

<Experimental Example 2>

The following properties were measured for the performance evaluation of the reverse osmosis membrane manufactured through the above Examples and Comparative Examples, and the results are shown in Table 1 below.

1. Measurement of permeate flux and salt removal rate

Permeate flow rate and salt removal rate (%) Performance measurements were performed in a 32,000 ppm sodium chloride aqueous solution at 25 ° C and 800 psi pressure in a cross-flow mode.

The flow rate is expressed by the flow rate of the obtained product water by the unit area and the flow rate per unit pressure, and the salt removal rate is a value showing the removal performance by measuring the ion conductivity (TDS) of the product water. .

Salt removal rate (%) = {1- (conductivity value of produced water / conductivity value of raw water)} x 100

2. Pressure resistance measurement

Permeate flow rate and salt removal rate under long-term high-temperature and high-pressure conditions were measured in a 32,000 ppm sodium chloride aqueous solution at 40 ° C under 853 psi pressure for 2 hours in a cross-flow mode.

The flow rate is expressed by the value of the flow rate of the obtained product water per unit volume per unit area and the salt removal rate is a value indicating the removal performance by measuring the ion conductivity value (TDS) of the product water, which can be obtained by the following method .

Salt removal rate (%) = {1- (Conductivity value of production water / Conductivity value of raw water)} × 10

Support performance Reverse osmosis membrane performance Pressure resistance evaluation
(2h, after 853 psi / 40 ° C operation) Permeate flow rate
(GFD) PEO removal rate (%) Permeate flow rate
(GFD) Salt Removal Rate (%) Permeate flow rate
(GFD) Salt Removal Rate (%) Flow rate reduction (%) Example 1 162.33 87.58 18.92 99.42 17.82 99.43 5.82 Example 2 172.24 88.22 18.77 99.51 17.75 99.50 5.45 Example 3 161.71 84.45 17.89 99.44 16.96 99.47 5.22 Example 4 150.67 81.85 16.49 99.39 15.68 99.43 4.89 Example 5 145.79 82.88 16.22 99.21 15.42 99.31 4.92 Example 6 126.14 83.21 15.99 99.15 15.23 99.21 4.78 Example 7 165.37 89.98 20.21 99.45 19.14 99.43 5.29 Example 8 173.15 88.48 20.85 99.50 19.62 99.51 5.92 Example 9 200.81 88.72 21.2 99.48 19.54 99.49 7.82 Example 10 159.92 85.88 18.80 98.55 16.81 99.03 10.58 Example 11 169.82 87.12 19.91 99.01 17.02 99.21 14.52 Comparative Example 1 158.43 83.29 19.10 99.31 14.71 99.38 22.98 Comparative Example 2 186.65 86.58 21.2 99.41 16.27 99.42 23.25 Comparative Example 3 155.43 87.88 18.92 99.29 16.77 99.33 11.36 Comparative Example 4 200.91 81.91 20.1 97.12 16.99 97.88 15.47

Specifically, as shown in Table 1, it can be seen that as the content of the inorganic particles increases, the permeate flow rate decreases at the permeate flow rate of the reverse osmosis membrane, the high pressure and the high temperature (Examples 1 to 5)

In addition, the smaller the particle size of the inorganic particles, the larger the flow rate at a pressure of 800 psi. However, the flow rate decreases when the particle size becomes smaller than a certain size at a high pressure of 853 psi and a high temperature of 40 캜. (Examples 1, 7 to 9 and Comparative Example 3)

In the case of Comparative Example 4 in which the particle size of the inorganic particles was 60 to 70 탆, the salt rejection rate was 97.88 in the pressure resistance evaluation, %, It can be confirmed that the removal rate is remarkably decreased.

In Examples 10 and 11 in which the inorganic particles were not glass beads but silica and / or titanium dioxide, the flow rate was increased under the pressure of 800 psi. However, in the case of high pressure of 853 psi and high temperature of 40 캜, It was found that the pressure resistance effect was insignificant and the pressure resistance remarkably decreased as compared with Examples 7 to 9.

In addition, it can be seen that the flow rate obtained as a result of the pressure resistance evaluation is significantly reduced in Comparative Example 1 which does not include the inorganic particles, as compared with Example 1, and the flow rate reduction rate significantly increases before applying the high pressure.

In Comparative Example 2 using carbon nanotubes as the inorganic particles, the permeation flow rate was excellent under the normal reverse osmosis condition as compared with Example 1, but the decrease in the permeation flow rate was remarkably reduced under the conditions of high pressure and high temperature .

Claims (20)

(1) treating a polymer solution containing inorganic particles having a particle diameter of 10 to 55 占 퐉 on at least one surface of a support to form a polymer support layer; And
(2) adding an aqueous solution containing a polyfunctional amine to the polymer support layer, and then contacting the polyimide layer with an organic solution containing a polyfunctional acid halide compound to form a polyamide layer. The method according to claim 1,
The polymer solution of step (1) may be one or more selected from the group consisting of N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylsulfoxide (DMSO), or dimethylacetamide And a solvent. The method according to claim 1,
The polymer solution in the step (1) may be at least one selected from the group consisting of polysulfone polymers, polyamide polymers, polyimide polymers, polyester polymers, olefin polymers, polyvinylidene fluoride, polybenzimidazole polymers and polyacrylonitrile Wherein the at least one polymeric material is selected from the group consisting of polyvinylidene fluoride (PVDF) and polyvinylidene fluoride (PVDF). The method according to claim 1,
Wherein the particle size of the inorganic particles in the step (1) is 10 to 30 占 퐉. The method according to claim 1,
Wherein the inorganic particles in step (1) are contained in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the polymer material contained in the polymer solution. The method according to claim 1,
Wherein the inorganic particles are spherical in shape and include at least one selected from the group consisting of silica, glass, glass modified by surface modification with a hydrophilic group, and titanium dioxide. The method according to claim 1,
Wherein the inorganic particles in step (1) are contained in an amount of 0.04 to 0.35 parts by weight based on 100 parts by weight of the polymer material contained in the polymer solution. The method according to claim 1,
Wherein the inorganic particles have a spherical shape and include at least one of a glass and a glass surface-modified with a hydrophilic group. A support;
A polymeric support layer formed on at least one surface of the support and including inorganic particles having a particle diameter of 10 to 55 mu m; And
And a polyamide layer formed on the polymer support layer. 10. The method of claim 9,
Wherein the support is a fabric or a nonwoven fabric. 10. The method of claim 9,
Wherein the polymer support layer has a thickness of 30 to 300 占 퐉. 10. The method of claim 9,
The polymer support layer may be at least one selected from the group consisting of a polysulfone polymer, a polyamide polymer, a polyimide polymer, a polyester polymer, an olefin polymer, polyvinylidene fluoride, a polybenzimidazole polymer, and polyacrylonitrile A reverse osmosis membrane having excellent pressure resistance, comprising at least one polymer material. 10. The method of claim 9,
Wherein the inorganic particles have a particle diameter of 10 to 30 占 퐉. 10. The method of claim 9,
Wherein the inorganic particles are contained in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the polymeric substance contained in the polymer support layer. 10. The method of claim 9,
Wherein the inorganic particles are spherical in shape and include at least one selected from the group consisting of silica, glass, glass modified with a hydrophilic group, and titanium dioxide. 10. The method of claim 9,
Wherein the inorganic particles are contained in an amount of 0.04 to 0.35 parts by weight based on 100 parts by weight of the polymer support layer. 10. The method of claim 9,
Wherein the inorganic particles are spherical in shape and include at least one of a glass and a glass surface-modified with a hydrophilic group. 10. The method of claim 9,
Wherein the reverse osmosis membrane has a permeation rate of 19 GFD or more and a salt removal rate of 99% or more after an operation at 40 ° C under a pressure of 853 psi for 2 hours in an aqueous solution containing 32,000 ppm sodium chloride. 10. The method of claim 9,
Wherein the reverse osmosis membrane has a flow rate reduction rate of 6.0% or less in an aqueous solution containing 32,000 ppm sodium chloride at 40 ° C under a pressure of 853 psi for 2 hours.
[Relation 1]

* Flow 1 is the permeate flow rate at 25 ° C and 800 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride.
* Flow 2 is the permeate flow rate after 2 hours of operation at 40 ° C and 853 psi pressure in an aqueous solution containing 32,000 ppm sodium chloride. A reverse osmosis module comprising a reverse osmosis membrane according to any one of claims 9 to 19.

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