KR102068656B1 - Method for preparing thin film nanocomposite membrane for the reverse osmosis having nano material layer and thin film nanocomposite membrane prepared thereby - Google Patents

Abstract

The present invention relates to a method for preparing a reverse osmosis nanocomposite membrane equipped with a nanomaterial layer, and to preparing a reverse osmosis nanocomposite membrane according to the present invention, depositing a nanomaterial-containing solution on a porous support; Primary immersing the porous support on which the nanomaterial is deposited in a solution containing polyfunctional amine; And immersing the porous support on which the immersed nanomaterial is deposited in a polyfunctional acyl halide-containing solution to form a polyamide selection layer. Thus, unlike the conventional method, the solvent is free to select a solvent and between the nanomaterial and the support. Excellent adhesion, not only does not waste nanomaterials, but also has the advantage of fast deposition time.

Description

Method for preparing thin film nanocomposite membrane for the reverse osmosis having nano material layer and thin film nanocomposite membrane prepared according to the present invention

Unlike the conventional method, the present invention provides a method for preparing a reverse osmosis nanocomposite membrane and a reverse osmosis nanocomposite membrane prepared according to the present invention, which are free from solvent selection, have excellent adhesion between nanomaterials and a support, and do not waste nanomaterials. It is about.

Low molecular weight organic substances, divalent or more metal salts, and the like dissolved in water can be effectively removed using a nanocomposite membrane. Nanocomposite membranes are membranes derived from reverse osmosis membranes, which are mainly used to remove organic substances having a molecular weight of 200 to 1000, divalent or higher metal salts, and low molecular weight organic substances, and the water permeation rate is about 5 to 10 times larger than that of reverse osmosis membranes. There is an advantage that can greatly save the cost and equipment.

The fields in which the nanocomposite membranes are mainly used include water purification systems, recycling of dyes contained in dyeing wastewater, softening soft water, and production of industrial water.

In order to expand the use of such nanocomposite membranes, several conditions must be satisfied. That is, it must be excellent in permeability, durability and compression resistance, and must be excellent in pH and temperature, bacterial attack and resistance to oxidizing substances such as chlorine. Most commercial membranes satisfy most of the above conditions, but the most important improvement is in improving permeability. Improving the permeability will reduce the process cost, operating cost, etc. of the process will increase the use of the nanocomposite membrane.

Since the introduction of the first reverse osmosis desalination process in the 1930s, much research has been carried out on semi-permeable membrane materials in this field. Among them, the main successes of commercial success are cellulose-based asymmetric membranes and polyamide-based composite membranes. Cellulose-based membranes developed in the early stages of reverse osmosis membranes have suffered from several shortcomings due to their narrow operating pH range, deformation at high temperatures, high operating costs using high pressure, and vulnerability to microorganisms. This is a rarely used trend.

Currently, polyamide composite membranes can improve low permeation rate and have excellent salt rejection rate, and are currently predominant in water treatment separation membranes. An amine monomer such as piperazine and m-phenylenediamine is mainly used for producing the polyamide composite membrane. For example, US 4,259,183 to JECadotte discloses a method for preparing a composite membrane by reacting piperazine with trimezoyl chloride / IPC, and based on the above technique, improved physical properties through additives and post-treatment. It is disclosed in these other patent documents. For example, US Pat. No. 4,765,897, US Pat. No. 4,812,270, US Pat. No. 4,824,574 disclose post-treatment with inorganic acids and Rejection enhancers, while US Pat. No. 6,280,853 covers membranes with epoxide materials. Post-treatment coating techniques are disclosed. US 4,769,148 and US 4,859,384 also disclose techniques for inducing a flow rate increase by adding a cationic humectant to the piperazine layer during membrane preparation. However, membranes prepared using piperazine have a problem in that it is difficult to increase salt rejection. In another method, after forming a polysulfone layer on the nonwoven fabric to form a microporous support, the microporous support is immersed in an aqueous solution of m-phenylenediamine to form an m-phenylenediamine layer, which is then trimesoyl chloride. A method of forming a polyamide layer by interfacial polymerization by contacting m-phenylenediamine and trimezoyl chloride by immersion or coating in an organic solvent has been attempted. The method is characterized in that the polymerization proceeds only at the interface by contacting the nonpolar and polar solutions to form a very thin polyamide layer.

As described above, the polyamide-based composite membrane has advantages of excellent water permeability, durability, and compression resistance. However, when used to treat dangerous substances such as sulfuric acid, the polyamide-based composite membrane has a problem in that the permeation rate and salt rejection rate are lowered because it can be operated under low pressure.

In addition, the polyamide-based composite membrane is manufactured by a supporting method. When the supporting method is used, the nanomaterial is wasted with the removal of the aqueous solution during the manufacturing process, and a long supporting time is required to increase the adhesion between the nanomaterial and the support. have.

Accordingly, there is a demand for a nanocomposite membrane that can increase the water permeability without lowering the salt rejection rate, and also has a short process time, shows excellent adhesion between the nanomaterial and the support, and does not waste nanomaterial.

Republic of Korea Patent No. 10-0477583 Republic of Korea Patent No. 10-1733264

It is an object of the present invention to provide a method for preparing a nanocomposite membrane for reverse osmosis, which is free from solvent selection, has excellent adhesion between nanomaterials and supports, does not waste nanomaterials, and has a fast deposition time, unlike conventional methods.

In addition, another object of the present invention to provide a nanocomposite membrane for reverse osmosis prepared according to the above method.

In addition, another object of the present invention to provide a reverse osmosis module including the reverse osmosis nanocomposite membrane.

Method for producing a nanocomposite membrane for reverse osmosis of the present invention for achieving the above object comprises the steps of depositing a nanomaterial containing solution on a porous support to form a nanomaterial deposition layer; Primary immersing the porous support on which the nanomaterial deposition layer is formed in a solution containing polyfunctional amine; And immersing the porous support on which the immersed nanomaterial deposition layer is formed in a polyfunctional acyl halide-containing solution to form a polyamide selection layer.

The concentration of the nanomaterial may be 0.01 to 0.1% by weight.

The nanomaterial-containing solution is deposited on the porous support using spray spray, spin coating, roll coating, or air knife method, preferably spray spray method.

The flow rate of the nanomaterial-containing solution sprayed from the spray may be 0.5 to 3 ml / min.

The solvent in which the nanomaterial is dispersed in the nanomaterial-containing solution may be selected under conditions in which the support is not dissolved, and water, ethanol, methanol, acetone, dimethylformaldehyde (DMF), dimethyl sulfoxide (DMSO), and N-methylpi It may be at least one member selected from the group consisting of rolidone (NMP), pyridine and tetrahydrofuran (THF).

The distance between the porous support and the spray nozzle may be 2 to 5 cm.

The injection speed of the nanomaterial-containing solution may be 100 to 500 mm / s.

The time that the nanomaterial-containing solution is deposited on one surface of the porous support may be 10 to 60 seconds based on 9 X 14 cm ² .

The nanomaterial may be at least one selected from the group consisting of carbon nanotubes, graphene oxide, metal organic frameworks, and zeolites.

The porous support is a coating layer of a polymeric material formed on a nonwoven fabric, the polymeric material is polysulfone, polyethersulfone, polyimide, polyethylene, polypropylene, polyamide, polyetherimide, polyacrylonitrile, polymethylmethacryl It may be one selected from the group consisting of latex and polyvinylidene fluoride.

The polyfunctional amine is m-phenylenediamine, p-phenylenediamine, 1,3,6-benzenetriamine, 4-chloro-1,3-phenylenediamine, 6-chloro-1,3-phenylenediamine And 3-chloro-1,4-phenylene diamine may be one or more selected from the group consisting of.

The multifunctional acyl halide may be at least one member selected from the group consisting of trimezoyl chloride, isophthaloylchlororai and terephthaloyl chloride.

In addition, the reverse osmosis nanocomposite membrane of the present invention for achieving the above another object may be prepared according to the method for producing the reverse osmosis nanocomposite membrane.

In addition, the reverse osmosis module of the present invention for achieving another object described above may include the reverse osmosis nanocomposite membrane.

Unlike the conventional method, the nanocomposite membrane for reverse osmosis of the present invention is free from solvent selection, has excellent adhesive strength between the nanomaterial and the support, and can save nanomaterials and has a fast deposition time.

In addition, the reverse osmosis nanocomposite membrane of the present invention showed a higher water permeability and retained salt rejection rate than the pure polyamide-based nanocomposite membrane, and especially compared to the nanocomposite membrane coated with the nanomaterial by conventional supporting method. The amount can be significantly reduced.

Such a reverse osmosis nanocomposite membrane can be used in reverse osmosis module, water treatment module, seawater desalination module, gas separation module.

1 is a graph showing the correlation between the water permeability and the salt rejection rate of the conventional polyamide-based reverse osmosis composite membrane.
2 is a flowchart illustrating a process of preparing a nanocomposite membrane coated with a nanomaterial on a conventional porous support.
3 is a SEM photograph showing poor deposition and uniform deposition according to the spray coating conditions of the present invention.
4A is a photograph taken by TEM of ZIF-8 nanoparticles, and FIG. 4B is a graph of XRD analysis of ZIF-8 nanoparticles.
5 is a flowchart illustrating a process of manufacturing a nanocomposite membrane for reverse osmosis according to Examples and Comparative Example 1 of the present invention.
6 is a SEM photograph of a porous support on which nanomaterials are deposited according to Examples 1 to 6 and Comparative Example 1 of the present invention.
7 is a photograph taken by 3D AFM of a porous support on which nanomaterials are deposited according to Examples 1 to 6 and Comparative Example 1 of the present invention.
Figure 8a is a graph measuring the contact angle of the porous support on which the nanomaterials are deposited according to Examples 1 to 6 and Comparative Example 1 of the present invention, Figure 8b is a nano in accordance with Examples 1 to 6 and Comparative Example 1 of the present invention The surface area change (SAD) of the porous support on which the material is deposited is measured and FIG. 8C shows solid-liquid interfacial energy (−) of the porous support on which the nanomaterial is deposited according to Examples 1 to 6 and Comparative Example 1 of the present invention. ΔGsl) is measured.
9 is a SEM photograph of the surface of the reverse osmosis nanocomposite membrane prepared according to Examples 1 to 6 and Comparative Example 1 of the present invention.

Conventional polyamide-based reverse osmosis composite membranes are polyamide-coated composite membranes on porous supports. As shown in FIG. 1, the higher the water permeability, the lower the salt rejection rate, thereby limiting the performance of the reverse osmosis membrane.

In order to improve the problem of the polyamide-based reverse osmosis composite membrane, as shown in FIG. 2, a nanocomposite membrane coated with a nanomaterial by a supporting method on a porous support has been developed. In the nanocomposite membrane using the supporting method, the porous support is immersed in a mixture of nanomaterials and a polyfunctional amine-containing solution to coat the nanomaterial on the porous support, remove excess solution, and then remove the remaining water on the surface of the porous support. Removed and immersed in a polyfunctional acyl halide containing solution to form a polyamide selective layer on the coated nanomaterial (corresponding to Comparative Example 1 herein). However, in order to use such a supporting method, water must be used as a solvent for the bonding of the porous support-nano material. Accordingly, when using a nano material that is not dispersed in water, since water is limited as a solvent for dispersing the nano material. Severe agglomeration occurs, reducing the performance of the nanocomposite membrane. In addition, in order to bond the porous support-nano material, the porous support should be immersed in the mixture of the nano material and the polyfunctional amine containing solution for a long time, and there is a problem that the nano material is wasted with the removal of the aqueous solution (water). .

The present invention, unlike the conventional method, can freely select solvents and save nanomaterials, as well as a method for preparing a reverse osmosis nanocomposite membrane having excellent adhesion between the nanomaterials and the support while the deposition time is fast, and the reverse osmosis nanomanufactured accordingly It relates to a composite membrane.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Method for producing a nanocomposite membrane for reverse osmosis of the present invention comprises the steps of (A) depositing a nanomaterial-containing solution on a porous support to form a nanomaterial deposition layer; (B) first immersing the porous support on which the nanomaterial deposition layer is formed in a solution containing polyfunctional amine; And (C) secondary immersing the porous support on which the immersed nanomaterial deposition layer is formed in a polyfunctional acyl halide-containing solution to form a polyamide selective layer.

First, in step (A), a nanomaterial-containing solution is deposited on a porous support to form a nanomaterial deposition layer.

The nanomaterial is not limited to 1D, 2D, 3D, and the like, and specifically, at least one selected from the group consisting of carbon nanotubes, graphene oxide, metal organic frameworks, and zeolites is preferably used.

The concentration of the nanomaterial is 0.01 to 0.1% by weight, preferably 0.025 to 0.05% by weight. When the concentration of the nanomaterial is less than the lower limit, the salt rejection rate does not decrease, but the water permeability may not be excellent. When the concentration of the nanomaterial is higher than the upper limit, aggregation and defects of the nanomaterial occur, so that the water rejection rate is excellent. This may be reduced, and elution of the nanomaterial may occur due to a defect generated in the composite film.

In addition, the method of depositing the nanomaterial-containing solution is not particularly limited as long as it is a method other than the supporting method, but preferably spray spray, spin coating, roll coating or air knife method, and more preferably spray spray method Can be mentioned.

The method of spraying with a spray among the methods for depositing the nanomaterial-containing solution is described as follows.

The polyamide selective layer formed on the upper surface of the nanomaterial deposition layer is coated without structural change, and even if a small amount of nanomaterial is used, the flow rate and porosity of the nanomaterial-containing solution sprayed from the spray to increase the water permeability without lowering the salt rejection rate The distance between the support and the spray nozzle and the spray rate of the nanomaterial-containing solution are important. For example, as shown in FIG. 3, when one or more of the flow rate of the nanomaterial-containing solution sprayed from the spray, the distance between the porous support and the spray nozzle, and the spray rate condition of the nanomaterial-containing solution are outside the scope of the present invention, As one of the problems, poor deposition (coating) may occur, and if the above conditions are satisfied, a uniform nanomaterial deposition layer may be obtained.

The flow rate of the nanomaterial-containing solution sprayed in the spray is 0.5 to 3 ml / min, preferably 0.8 to 1.5 ml / min. If the flow rate is less than the lower limit, it takes a long time to deposit, so that it is difficult to deposit the desired amount of nanomaterials in a single process. If the flow rate is higher than the upper limit, aggregation of the nanomaterials occurs due to a high flow rate, causing defects in the composite film. can do.

In addition, the distance between the porous support and the spray nozzle is 2 to 5 cm, preferably 3 to 4 cm. If the distance between the porous support and the spray nozzle is less than the lower limit, the nanomaterial may not be uniformly coated but deposited locally to cause defects. If the upper limit is exceeded, the sprayed solution may not be deposited on the support and may be lost. The content of nanomaterials can be high.

In addition, the injection speed of the nanomaterial-containing solution is 100 to 500 mm / s, preferably 200 to 300 mm / s. If the spraying speed is less than the lower limit, the deposition time takes a lot, and the adhesion between the nanomaterial and the porous support may be lowered. If the spraying speed is higher than the upper limit, the adhesion between the nanomaterial and the porous support is lowered and a polyamide selective layer is formed thereafter. Deformation of may occur.

When the nanomaterial-containing solution is deposited on one surface of the porous support under such conditions, the deposition time is 10 to 60 seconds, preferably 40 to 50 seconds, based on 9 × 14 cm ² . When the deposition time is outside the above range, at least one of the flow rate of the nanomaterial-containing solution sprayed from the spray, the distance between the porous support and the spray nozzle, and the spray rate of the nanomaterial-containing solution is beyond the scope of the present invention. The effect of may be lowered.

The nanomaterial-containing solution used in the present invention is a material in which nanomaterials are dispersed in a solvent, and the solvent is not particularly limited as long as the material can disperse the nanomaterial without dissolving the support, but preferably water, ethanol and methanol , Acetone, dimethylformaldehyde (DMF), dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), pyridine and tetrahydrofuran (THF). Specifically, since the present invention deposits the nanomaterial-containing solution by a method such as spray injection, the solvent is not limited to water unlike the conventional.

In addition, the porous support used is a coating layer of a polymer material formed on a nonwoven fabric, the polymer material is polysulfone, polyethersulfone, polyimide, polyethylene, polypropylene, polyamide, polyetherimide, polyacrylonitrile, polymethyl It may be one selected from the group consisting of methacrylate and polyvinylidene fluoride.

Next, in the step (B), the porous support on which the nanomaterial is deposited is first immersed in a polyfunctional amine-containing solution.

The polyfunctional amine compound in the polyfunctional amine-containing solution is not particularly limited as long as it is a polyfunctional amine compound that can be used in the nanocomposite membrane for reverse osmosis, preferably m-phenylenediamine, p-phenylenediamine, 1,3 At least one selected from the group consisting of 6-benzenetriamine, 4-chloro-1,3-phenylenediamine, 6-chloro-1,3-phenylenediamine and 3-chloro-1,4-phenylenediamine Can be.

The method of forming the layer containing the polyfunctional amine compound on the upper surface of the nanomaterial deposition layer of the porous support is not particularly limited, but preferably spraying, coating, dipping, dropping, and the like, and more preferably dipping. Can be mentioned. When the immersion method is used to form a layer including the polyfunctional amine compound on the upper surface of the nanomaterial deposition layer, the immersion is performed for 30 seconds to 5 minutes. If the immersion time is less than the lower limit, the layer containing the polyfunctional amine compound may not be formed properly, so that a part of the polyamide selection layer may not be formed later. If the upper limit is exceeded, the process time is long and the Losses may occur.

In addition, the solvent in the polyfunctional amine-containing solution is not particularly limited as long as it is a substance capable of dissolving the polyfunctional amine compound. Preferably, the solvent is selected from the group consisting of water, pentane, hexane, and heptane. It may be one or more selected.

In this case, the layer including the multifunctional amine compound formed on the nanomaterial deposition layer may be additionally performed to remove the solution containing the excess polyfunctional amine compound as necessary. The layer including the multifunctional amine compound formed on the nanomaterial deposition layer may be unevenly distributed when there are too many solutions present on the nanomaterial deposition layer, and when the solution is unevenly distributed, subsequent interfacial polymerization By means of which a non-uniform polyamide selective layer can be formed. Therefore, it is preferable to remove excess solution after forming the layer including the multifunctional amine compound on the nanomaterial deposition layer. In this case, since the nanomaterial is fixed in the form of a deposition layer, the nanomaterial is not removed together when the polyfunctional amine compound is removed.

The method for removing the excess solution is not particularly limited, but may be preferably performed using a sponge, air knife, nitrogen gas blowing, air drying, or a compression roll.

Next, in step (C), the porous support prepared in step (B) is immersed in a polyfunctional acyl halide-containing solution for the second time to form a polyamide selective layer.

Specifically, the polyfunctional amine compound coated on the surface and the polyfunctional acyl halide compound react to form polyamide by interfacial polymerization, and are adsorbed onto the porous nanomaterial to form a thin film. If a nonporous material is used instead of a porous nanomaterial, the polyamide selective layer cannot be formed.

The method for forming the polyamide selective layer by reacting the layer containing the polyfunctional amine compound with the polyfunctional acyl halide compound is not particularly limited, but preferably spraying, coating, dipping, dropping, and the like are more preferable. Immersion is possible. When using the dipping method to form the polyamide selective layer, it is immersed for 30 seconds to 5 minutes. If the immersion time is less than the lower limit, a portion in which the polyamide select layer is not formed may occur. If the immersion time is exceeded, the process time may be longer and deformation of the polyamide select layer may occur.

The polyfunctional acyl halide compound in the polyfunctional acyl halide-containing solution is not particularly limited as long as it is a polyfunctional acyl halide compound that can be used in the reverse osmosis nanocomposite membrane. And at least one selected from the group consisting of royl chloride.

In addition, the solvent in the polyfunctional acyl halide-containing solution is not particularly limited as long as it is a substance capable of dissolving the polyfunctional acyl halide compound, but is preferably a solvent having 8 to 15 carbon atoms, and more preferably octane. It may be at least one selected from the group consisting of nonane, decane, decane, undecane and dodecane.

The reverse osmosis nanocomposite membrane may be prepared according to the preparation method, and the prepared reverse osmosis nanocomposite membrane may be used for a reverse osmosis module, a water treatment module, a seawater desalination module, a gas separation module, and the like.

Hereinafter, preferred examples are provided to help the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and various changes and modifications within the scope and spirit of the present invention are apparent to those skilled in the art. It is natural that such variations and modifications fall within the scope of the appended claims.

Preparation Example 1. Nanomaterial_ZIF-8

ZIF-8 (zeolitic imidazole framework-8) is a metal-organic framework that has a very high specific surface area (~ 1,600 m ² / g) and a molecular pore size (3.4 Å). Successful synthesis of the ZIF-8 was confirmed by TEM image and XRD analysis.

4A is a photograph taken by TEM of ZIF-8 nanoparticles, and FIG. 4B is a graph of XRD analysis of ZIF-8 nanoparticles.

Examples 1-6.

ZIF-8 Nanoparticle Deposition

After dispersing the ZIF-8 nanoparticles in ethanol, the dispersion is sprayed onto the porous support (Toray, PSf support) by spray coating to evenly deposit the ZIF-8 nanoparticles onto the porous support. At this time, the concentration of ZIF-8 nanoparticles in the dispersion was 0.01% by weight (Example 1), 0.025% by weight (Example 2), 0.05% by weight (Example 3), 0.1% by weight (Example 4), 0.25% by weight % (Example 5), 0.5% by weight (Example 6), the flow rate of the ZIF-8 nanoparticle-containing solution sprayed in the spray is 1 ml / min, the distance between the porous support and the spray nozzle is 3 cm, ZIF-8 The spraying speed of the nanoparticle-containing solution was 300 mm / s. The key parameters during spray coating were optimized to uniformly deposit ZIF-8 nanoparticles on a 126 cm ² support in 50 seconds in a short time.

Polyamide Selective Layer Formation

After immersing the porous support on which the ZIF-8 nanoparticles were deposited in an MPD solution in which MPD (m-phenylene diamine) was dissolved in ultrapure water for 1 minute, the excess solution was removed and the ZIF-8 nanoparticles immersed in the MPD solution The deposited porous support was immersed in a TMC solution in which TMC (Trimesoyl chloride) was dissolved in n-decane solvent for 1 minute to form a polyamide selective layer on ZIF-8 nanoparticles to prepare a nanocomposite membrane for reverse osmosis ( 5).

Comparative Example 1.

After immersing the porous support (Toray, PSf support) for 10 minutes in a mixed solution containing MPD (m-phenylene diamine) dissolved in ultrapure water and 0.2% by weight of ZIF-8 nanoparticles, the excess solution was removed, and then ZIF The porous support on which -8 nanoparticles were deposited was immersed in a TMC solution in which TMC (Trimesoyl chloride) was dissolved in a n-decane solvent for 1 minute to form a polyamide selective layer on ZIF-8 nanoparticles. A composite membrane was prepared (FIG. 5).

<Test Example>

Test Example 1 SEM Image _Deposited Nanomaterial

6 is a SEM photograph of a porous support on which nanomaterials are deposited according to Examples 1 to 6 and Comparative Example 1 of the present invention.

As shown in FIG. 6, even when spray coating was used according to Examples 1 to 6, it was confirmed that uniform nanomaterial deposition at the level of the supporting method of Comparative Example 1 was possible.

Test Example 2 3D AFM Image Capture_Deposited Nanomaterial

7 is a photograph taken by 3D AFM of a porous support on which nanomaterials are deposited according to Examples 1 to 6 and Comparative Example 1 of the present invention.

As shown in FIG. 7, it was confirmed that the surface roughness of the porous support on which the nanomaterials were deposited according to Examples 1 to 6 was increased as the content of the nanomaterial was increased. In addition, it was confirmed that the surface roughness of Examples 2 to 4 of the present invention is similar to Comparative Example 1.

Test Example 3 Measurement of Wetting and Surface Area Change_Deposited Nanomaterials

Figure 8a is a graph measuring the contact angle of the porous support on which the nanomaterials are deposited according to Examples 1 to 6 and Comparative Example 1 of the present invention, Figure 8b is a nano in accordance with Examples 1 to 6 and Comparative Example 1 of the present invention. The surface area change (SAD) of the porous support on which the material is deposited is measured and FIG. 8C shows solid-liquid interfacial energy (−) of the porous support on which the nanomaterial is deposited according to Examples 1 to 6 and Comparative Example 1 of the present invention. ΔGsl) is measured.

The solid-liquid interfacial energy (-ΔGsl) value may be measured using the measured values of the contact angle and the surface area change.

As shown in FIGS. 8A to 8C, the porous support on which nanomaterials are deposited according to Examples 1 to 6 decreases the solid-liquid interfacial energy (-ΔGsl) value as the content of the nanomaterial increases. As the content of the material increases, it means that the surface becomes more hydrophobic.

Test Example 4. SEM Image _ Nano Composite Membrane

9 is a SEM photograph of the surface of the reverse osmosis nanocomposite membrane prepared according to Examples 1 to 6 and Comparative Example 1 of the present invention.

As shown in FIG. 9, Examples 1 to 4 of the present invention confirmed that the polyamide layer was formed uniformly without deformation in the same manner as in Comparative Example 1 using the supporting method. On the other hand, in Examples 5 and 6, deformation occurred in the process of forming the polyamide layer, which is considered to be due to the hydrophobic surface.

Test Example 5 Measurement of Salt Exclusion Rate and Water Permeability According to Nanomaterial Concentration

The salt rejection rate (salt removal rate) and water permeability were measured at a pressure of 15.5 bar while feeding 2,000 ppm aqueous sodium chloride solution at 25 ° C. at a flow rate of 2 L / min. The membrane cell device used for the membrane evaluation was equipped with a flat plate permeation cell, a high pressure pump, a storage tank, and a cooling device. The structure of the flat plate permeation cell was 32-cm ² in a cross-flow manner. After the washed separation membrane was installed in the permeation cell, sufficient preliminary operation was performed for about 1 hour using tertiary distilled water to stabilize the evaluation equipment. Subsequently, the instrument was operated for about 1 hour until the pressure and permeate flow reached a steady state by replacing with 2,000 ppm aqueous sodium chloride solution, and then the flow rate was calculated by measuring the amount of water permeated for 10 minutes, and the conductivity meter (Conductivity Meter) Salt exclusion rate was calculated by analyzing the salt concentration before and after permeation. The measurement results are shown in the following [Table 1].

As a control, the same procedure as in Comparative Example 1 was performed, but the reverse osmosis nanocomposite membrane prepared without using the nanomaterial ZIF-8 nanoparticles was used.

division ZIF-8 concentration (% by weight) when spray coating Required amount of ZIF-8 per area (mg / m ² ) Water permeability
(LMH / bar)
(Lm ^-2 h ^-1 bar ^-1 ) NaCl exclusion rate
(%) Control - - 2.86 96.57 Comparative Example 1 - 3170 3.73 97.52 Example 1 0.01 6 3.14 97.35 Example 2 0.025 30 3.50 97.34 Example 3 0.05 60 3.72 97.83 Example 4 0.1 120 3.29 97.07 Example 5 0.25 300 3.81 83.63 Example 6 0.5 600 4.91 57.64

As shown in Table 1, the reverse osmosis nanocomposite membrane prepared according to Examples 1 to 4 of the present invention was confirmed that the water permeability is also improved without reducing the salt rejection rate.

On the other hand, Examples 5 and 6 confirmed that the water permeability is improved but the salt rejection rate is reduced.

In addition, it was confirmed that the reverse osmosis nanocomposite membranes of Examples 1 to 4 of the present invention have improved water permeability of 30% or more compared to the reverse osmosis nanocomposite membrane of the control group, and about 40 times or more than the reverse osmosis nanocomposite membrane of Comparative Example 1 It was confirmed that a small amount of nanomaterials showed similar water permeability and salt rejection rate.

Claims (15)

Depositing a nanomaterial-containing solution on a porous support by spray spraying to form a nanomaterial deposition layer;
Primary immersing the porous support on which the nanomaterial deposition layer is formed in a solution containing polyfunctional amine; And
And immersing the porous support on which the immersed nanomaterial deposition layer is formed in a polyfunctional acyl halide-containing solution to form a polyamide selective layer.
The porous support is a method of manufacturing a nanocomposite membrane for reverse osmosis, characterized in that a coating layer of a polymer material is formed on a nonwoven fabric. The method according to claim 1, wherein the concentration of the nanomaterial is 0.01 to 0.1% by weight. delete delete The method of claim 1, wherein the flow rate of the nanomaterial-containing solution sprayed from the spray is 0.5 to 3 ml / min. The method of claim 1, wherein the distance between the porous support and the spray nozzle is 2 to 5 cm. The method of claim 1, wherein the injection speed of the nanomaterial-containing solution is 100 to 500 mm / s. The method of claim 1, wherein the time for depositing the nanomaterial-containing solution on one surface of the porous support is 10 to 60 seconds based on 9 × 14 cm ² . The method of claim 1, wherein the nanomaterial is at least one selected from the group consisting of carbon nanotubes, graphene oxide, metal organic frameworks, and zeolites. The method of claim 1, wherein the solvent in which the nanomaterial is dispersed in the nanomaterial-containing solution is water, ethanol, methanol, acetone, dimethylformaldehyde (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP) , Pyridine and tetrahydrofuran (THF) method of producing a nanocomposite membrane for reverse osmosis, characterized in that at least one selected from the group consisting of. The method of claim 1, wherein the polymer material comprises polysulfone, polyethersulfone, polyimide, polyethylene, polypropylene, polyamide, polyetherimide, polyacrylonitrile, polymethylmethacrylate, and polyvinylidene fluoride. Method for producing a nanocomposite membrane for reverse osmosis, characterized in that one selected from the group. The method of claim 1, wherein the multifunctional amine is m-phenylenediamine, p-phenylenediamine, 1,3,6-benzenetriamine, 4-chloro-1,3-phenylenediamine, 6-chloro-1 Method for producing a nanocomposite membrane for reverse osmosis, characterized in that at least one selected from the group consisting of, 3-phenylenediamine and 3-chloro-1,4-phenylene diamine. The method of claim 1, wherein the polyfunctional acyl halide is at least one selected from the group consisting of trimezoyl chloride, isophthaloyl chlorlai, and terephthaloyl chloride. The reverse osmosis nanocomposite membrane prepared according to the method for preparing the reverse osmosis nanocomposite membrane of any one of claims 1, 2, and 5 to 13. Reverse osmosis module comprising a nanocomposite membrane for reverse osmosis of claim 14.

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