KR20170047114A - Method for manufacturing water-treatment membrane, water-treatment membrane manufactured by thereof, and water treatment module comprising membrane - Google Patents

Abstract

The present invention provides a production method of water-treatment membrane, a water-treatment membrane produced using the same, a water-treatment module comprising the water-treatment membrane. The production method of water-treatment membrane comprises the steps of: preparing a structure including a polyamide active layer provided on a porous support; and modifying the polyamide active layer using a solution containing peroxide.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a water treatment module including a water treatment membrane and a water treatment membrane including the water treatment membrane and the water treatment membrane produced by the method, and a water treatment module including the water treatment membrane,

The present invention provides a water treatment module including a method for manufacturing a water treatment membrane, a water treatment membrane manufactured using the same, and a water treatment membrane.

Due to the serious pollution and water shortage in recent years, it is urgent to develop new water resources. Studies on the pollution of water quality are aiming at the treatment of high quality living and industrial water, various domestic sewage and industrial wastewater, and interest in the water treatment process using the separation membrane having the advantage of energy saving is increasing. In addition, the accelerated enforcement of environmental regulations is expected to accelerate the activation of membrane technology. Conventional water treatment process is difficult to meet the regulations that are strengthened, but membrane technology is expected to become a leading technology in the water treatment field because it guarantees excellent treatment efficiency and stable treatment.

Liquid separation is classified into micro filtration, ultrafiltration, nano filtration, reverse osmosis, sedimentation, active transport and electrodialysis depending on the pores of the membrane. Among them, the reverse osmosis method refers to a process of desalting using a semi-permeable membrane which is permeable to water but impermeable to salt. When high-pressure water containing salt is introduced into one side of the semipermeable membrane, Will come out on the other side with low pressure.

In recent years, approximately 1 billion gal / day of water has been subjected to dechlorination through the reverse osmosis process. Since the first reverse osmosis process using the reverse osmosis in the 1930s was announced, many of the semi- Research was conducted. Among them, cellulose-based asymmetric membranes and polyamide-based composite membranes have become mainstream in commercial success. The cellulosic membranes developed at the beginning of the reverse osmosis membrane have various drawbacks such as narrow operating pH range, high temperature deformation, high cost of operation due to high pressure, and vulnerability to microorganisms Is a rarely used trend.

On the other hand, the polyamide-based composite membrane is formed by forming a polysulfone layer on a nonwoven fabric to form a microporous support, and immersing the microporous support in an aqueous solution of m-phenylenediamine (hereinafter referred to as mPD) And then the resultant is immersed or coated in an organic solution of triMesoyl Chloride (hereinafter referred to as TMC) to form a polyamide active layer by interfacial polymerization with the mPD layer in contact with TMC. By contacting the nonpolar solution with the polar solution, the polymerization takes place at the interface only and forms a very thin polyamide layer. The polyamide-based composite membrane has higher stability against pH change, can operate at lower pressure, and has a higher salt removal rate than conventional cellulose-based asymmetric membranes, and is currently a mainstream of water treatment membranes.

Studies on increasing the salt removal rate and permeate flow rate of such polyamide composite membranes have been continuously carried out.

Korean Patent Publication No. 10-1999-0019008

The present specification intends to provide a water treatment membrane having improved durability and salt removal rate and a method for producing the same.

One embodiment of the present disclosure relates to a method for fabricating a porous structure, comprising: preparing a structure including a polyamide active layer provided on a porous support; And a step of modifying the polyamide active layer using a solution containing a peroxide.

One embodiment of the present invention provides a water treatment separation membrane produced by the above production method.

One embodiment of the present disclosure provides a water treatment module comprising at least one water treatment separation membrane.

The water treatment separator produced by the production method according to one embodiment of the present invention exhibits an excellent salt removal rate.

The water treatment separation membrane manufactured by the manufacturing method according to one embodiment of the present invention has an advantage of excellent durability according to pH change.

 The water treatment separation membrane produced by the manufacturing method according to one embodiment of the present invention has an advantage of excellent chemical durability. Specifically, the water treatment separator according to one embodiment of the present invention has an advantage of excellent resistance to an acid or a base.

1 shows a water treatment separator according to an embodiment of the present invention.

When a member is referred to herein as being "on " another member, it includes not only a member in contact with another member but also another member between the two members.

Whenever a component is referred to as "comprising ", it is to be understood that the component may include other components as well, without departing from the scope of the present invention.

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

One embodiment of the present disclosure relates to a method for fabricating a porous structure, comprising: preparing a structure including a polyamide active layer provided on a porous support; And a step of modifying the polyamide active layer using a solution containing a peroxide.

Modifying the polyamide active layer may mean oxidizing the polyamide active layer.

Through the step of modifying the polyamide active layer, the chemical durability of the polyamide active layer can be improved. Specifically, the step of modifying the polyamide active layer can prevent the performance of the polyamide active layer from being degraded by an acid or a base by previously oxidizing a functional group capable of reacting with the acid or base of the polyamide active layer.

According to one embodiment of the present disclosure, the peroxide may be selected from the group consisting of hydrogen peroxide, sulfur peroxide, chlorine peroxide and peroxynitric acid.

According to one embodiment of the present invention, the content of the peroxide may be 0.001 wt% or more and 5 wt% or less with respect to the solution. Specifically, according to one embodiment of the present invention, the content of the peroxide may be 0.005 wt% or more and 1 wt% or less, or 0.005 wt% or more and 0.1 wt% or less with respect to the solution.

In the case of the content of the peroxide within the above range, the solution containing the peroxide can minimize the damage of the polyamide active layer and prevent the performance degradation of the polyamide active layer. Furthermore, in the case of the content of the peroxide within the above range, the solution containing the peroxide can effectively perform the modification of the polyamide active layer.

According to one embodiment of the present disclosure, the solution containing the peroxide can be aqueous-soluble for daily use. Specifically, the solution containing the peroxide can use water as a solvent.

According to one embodiment of the present invention, the solution containing the peroxide may further comprise a pH adjusting agent.

According to one embodiment of the present invention, the pH adjusting agent may be selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide and sodium hydrogencarbonate.

The pH adjusting agent may serve as a catalyst for the peroxide. Specifically, the pH adjusting agent may further activate the modification of the polyamide active layer of the peroxide. Specifically, the pH adjusting agent may serve as a catalyst for dissociating the peroxide, and the dissociated peroxide may modify the polyamide active layer to induce improvement in performance and durability.

According to one embodiment of the present disclosure, the pH of the solution containing the peroxide may be 3 or less or pH 9 or higher. Specifically, the pH of the solution containing the peroxide may be 1 or more and 3 or less, or pH 9 or more and 14 or less.

When the pH of the solution containing the peroxide shows an acidity of 3 or less, the pH adjuster may act as a catalyst for the peroxide. When the pH of the solution containing the peroxide exhibits a basicity of 9 or more, the pH adjuster may serve as a catalyst for the peroxide.

According to one embodiment of the present invention, the step of modifying the polyamide active layer may be to bring the polyamide active layer into contact with a solution containing the peroxide. Specifically, the step of modifying the polyamide active layer may include a method of applying a solution containing the peroxide to the polyamide active layer, a method of immersing the polyamide active layer in a solution containing the peroxide, A method of injecting a solution containing the peroxide into the water treatment module after incorporation into a water treatment module may be used. However, the present invention is not limited to the above-mentioned method, and any method may be used without limitation as long as the solution containing the peroxide is in contact with the polyamide active layer.

One embodiment of the present invention provides a water treatment separation membrane produced by the above production method.

According to one embodiment of the present invention, the water treatment separation membrane may have a salt removal rate of 0.1% or higher as compared with the case where the step of modifying the polyamide active layer is not performed.

1 shows a water treatment separator according to an embodiment of the present invention. 1 illustrates a water treatment separation membrane sequentially provided with a nonwoven fabric 100, a porous support 200 and a polyimide active layer 300. The brine 400 flows into the polyamide active layer 300, The purified water 500 is discharged through the nonwoven fabric 100 and the concentrated water 600 is discharged to the outside without passing through the polyamide active layer 300. However, the water treatment separation membrane according to one embodiment of the present invention is not limited to the structure of FIG. 1, and further constitution may be further included.

According to one embodiment of the present invention, the porous support may be formed with a coating layer of a polymer material on a nonwoven fabric. Examples of the polymeric material include polymeric materials such as polysulfone, polyethersulfone, polycarbonate, polyethylene oxide, polyimide, polyetherimide, polyetheretherketone, polypropylene, polymethylpentene, polymethyl chloride and polyvinylidene fluoride Rides, and the like may be used, but the present invention is not limited thereto. Specifically, polysulfone may be used as the polymer material.

According to one embodiment of the present invention, the polyamide active layer can be formed through an interfacial polymerization of an aqueous solution containing an amine compound and an organic solution containing an acyl halide compound. Specifically, the polyamide active layer is formed by forming an aqueous solution layer containing an amine compound on a porous support; And contacting the organic solvent containing an organic solvent with an acyl halide compound on an aqueous solution layer containing the amine compound to form a polyamide active layer.

When the aqueous solution containing the amine compound is brought into contact with the organic solution, the amine compound coated on the surface of the porous support reacts with the acyl halide compound to form polyamide by interfacial polymerization, and adsorbed on the microporous support, . In the contact method, a polyamide active layer may be formed by a method such as dipping, spraying, or coating.

According to one embodiment of the present invention, a method of forming an aqueous solution layer containing an amine compound on the porous support is not particularly limited, and any method can be used as long as it is capable of forming an aqueous solution layer on a support. Specifically, a method of forming an aqueous solution layer containing an amine compound on the porous support includes spraying, coating, dipping, dropping, and the like.

At this time, the aqueous solution layer may be further subjected to a step of removing an aqueous solution containing an excess of the amine compound, if necessary. The aqueous solution layer formed on the porous support may be unevenly distributed when the aqueous solution present on the support is excessively large. If the aqueous solution is unevenly distributed, a non-uniform polyamide active layer may be formed by subsequent interfacial polymerization have. Therefore, it is preferable to remove the excess aqueous solution after forming the aqueous solution layer on the support. The removal of the excess aqueous solution is not particularly limited, but can be performed using, for example, a sponge, an air knife, nitrogen gas blowing, natural drying, or a compression roll.

According to one embodiment of the present invention, in the aqueous solution containing the amine compound, the amine compound is not limited as long as it is an amine compound used in the preparation of a water treatment separation membrane, but specific examples include m-phenylenediamine, p - phenylenediamine, 1,3,6-benzenetriamine, 4-chloro-1,3-phenylenediamine, 6-chloro-1,3-phenylenediamine, 3- Or a mixture thereof.

According to one embodiment of the present disclosure, the acyl halide compounds include, but are not limited to, for example, aromatic compounds having 2 to 3 carboxylic acid halides, such as trimethoyl chloride, isophthaloyl chlorides, Terephthaloyl chloride, and mixtures of at least one compound selected from the group consisting of terephthaloyl chloride.

According to one embodiment of the present invention, the organic solvent may be an aliphatic hydrocarbon solvent, for example, a hydrophobic liquid such as Freons and a water-immiscible hydrophobic liquid such as hexane, cyclohexane, heptane or alkane having 5 to 12 carbon atoms, An alkane having 5 to 12 carbon atoms and mixtures thereof such as IsoPar (Exxon), ISOL-C (SK Chem), and ISOL-G (Exxon) may be used.

According to one embodiment of the present invention, the water treatment separation membrane can be used as a microfiltration membrane, an ultrafiltration membrane, a nano filtration membrane or a reverse osmosis membrane, Can be used.

In addition, one embodiment of the present disclosure provides a water treatment module comprising at least one water treatment separation membrane. According to one embodiment of the present disclosure, the water treatment module may include at least one water treatment separation membrane.

The specific type of the water treatment module is not particularly limited, and examples thereof include a plate & frame module, a tubular module, a hollow & fiber module, or a spiral wound module. In addition, as long as the water treatment module includes the water treatment separation membrane according to one embodiment of the present invention, other structures and manufacturing methods are not particularly limited and general means known in the art can be employed without limitation have.

On the other hand, the water treatment module according to one embodiment of the present invention has excellent salt removal rate and permeation flow rate, and is excellent in chemical stability, and thus can be used for water treatment devices such as household / industrial water purification devices, sewage treatment devices, have.

Hereinafter, the present invention will be described in detail by way of examples with reference to the drawings. However, the embodiments according to the present disclosure can be modified in various other forms, and the scope of the present specification is not construed as being limited to the embodiments described below. Embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art.

[Example 1]

A structure having a polyamide active layer with a thickness of 100 nm to 200 nm formed on a porous polysulfone support was washed with deionized water. Then, the polyamide active layer was modified by immersing in 0.1 wt% H ₂ S ₂ O ₈ aqueous solution for 30 minutes, and then washed with deionized water to prepare a water treatment membrane.

[Example 2]

The pH was adjusted to 2 with acetic acid A water treatment separation membrane was prepared in the same manner as in Example 1, except that the polyamide active layer was modified using 0.1 wt% H ₂ S ₂ O ₈ aqueous solution.

[Example 3]

The pH was adjusted to 10 with sodium hydroxide A water treatment separation membrane was prepared in the same manner as in Example 1, except that the polyamide active layer was modified using 0.1 wt% H ₂ S ₂ O ₈ aqueous solution.

[Example 4]

The pH was adjusted to 2 with acetic acid A water treatment separation membrane was prepared in the same manner as in Example 1, except that the polyamide active layer was modified using 0.1 wt% H ₂ O ₂ aqueous solution.

[Comparative Example 1]

A water treatment separation membrane was prepared in the same manner as in Example 1, except that the polyamide active layer was not modified.

[Comparative Example 2]

A water treatment separation membrane was prepared in the same manner as in Example 1, except that the polyamide active layer was modified with 0.1 wt% aqueous NaOCl solution.

[Comparative Example 3]

The pH was adjusted to 10 with sodium hydroxide A water treatment separation membrane was prepared in the same manner as in Example 1, except that the polyamide active layer was modified with 0.1 wt% aqueous NaOCl solution.

In order to measure the salt rejection and permeate flow rate (gfd) of the water treatment membranes prepared according to the above Examples and Comparative Examples, a water treatment module comprising a plate type permeation cell, a high pressure pump, a storage tank and a cooling device was used . The planar transmissive cell had a cross-flow structure with an effective permeable area of 28 cm 2. After the reverse osmosis membrane was installed in the permeable cell, the preliminary operation was performed for about 1 hour using the third distilled water to stabilize the evaluation equipment. Thereafter, the equipment was operated at a flow rate of 225 psi and 4.5 L / min in an aqueous solution of 2000 ppm sodium chloride for 1 hour to confirm that it stabilized, and then the amount of water permeated at 25 ° C for 10 minutes was measured to calculate the flux , And the salt rejection rate was calculated by analyzing the salt concentration before and after the permeation using a conductivity meter.

In order to measure the chemical durability of the water treatment membranes prepared according to Examples and Comparative Examples, CIP (clean in place) treatment was performed. The CIP treatment is generally carried out for the regeneration of a water treatment separation membrane. The water treatment separation membrane is allowed to stand in an atmosphere of 35 ° C and pH 13 for 3 hours and then left in an atmosphere of 35 ° C and pH 2 for 1 hour .

The performance of the water treatment separator according to the above Examples and Comparative Examples is shown in Table 1 below.

Initial Performance Performance after 3 cycles of CIP treatment Performance change rate (%) after 3 cycles of CIP treatment Salt removal rate
(%) Permeate flow rate
(GFD) Salt removal rate
(%) Permeate flow rate
(GFD) Rate of change of salt removal rate Rate of change of permeate flow rate Example 1 99.61 22.00 99.59 25.08 -0.02 14 Example 2 99.7 21.62 99.62 23.13 -0.08 7 Example 3 99.69 19.73 99.64 21.70 -0.05 10 Example 4 99.68 22.24 99.67 23.42 -0.01 6 Comparative Example 1 99.56 23.24 99.04 28.35 -0.52 22 Comparative Example 2 99.72 28.31 99.40 33.12 -0.32 17 Comparative Example 3 99.73 26.55 99.55 29.73 -0.18 12

After the CIP treatment, the reverse osmosis membrane shows a decrease in the salt removal rate and an increase in the permeation flow rate in comparison with the initial performance. This is because the polyamide active layer is damaged by chemicals during the CIP process. However, the chemical durability of the polyamide active layer was improved by modifying the polyamide active layer using the peroxide as the water treatment separation membrane according to the embodiment, which can be confirmed by the fact that the performance change after CIP treatment is very small as shown in Table 1 .

100: Nonwoven fabric
200: Porous support
300: polyamide active layer
400: brine
500: Purified water
600: concentrated water

Claims (11)

Preparing a structure comprising a polyamide active layer provided on a porous support; And
And modifying the polyamide active layer using a solution containing peroxide. The method according to claim 1,
Wherein the peroxide is selected from the group consisting of hydrogen peroxide, sulfur peroxide, chlorine peroxide and peroxynitric acid. The method according to claim 1,
Wherein the content of the peroxide is 0.001 wt% to 5 wt% with respect to the solution. The method according to claim 1,
Wherein the solution containing the peroxide further comprises a pH adjusting agent. The method of claim 4,
Wherein the pH adjusting agent is selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide and sodium hydrogencarbonate. The method according to claim 1,
Wherein the pH of the solution containing the peroxide is 3 or less or the pH is 9 or more. The method according to claim 1,
Wherein the step of modifying the polyamide active layer comprises contacting the polyamide active layer with a solution containing the peroxide. The method according to claim 1,
Wherein the polyamide active layer is formed using an interfacial polymerization of an aqueous solution containing an amine compound and an organic solution containing an acyl halide compound. A water treatment membrane produced by the manufacturing method according to claim 1. The method of claim 9,
Wherein the water treatment separation membrane has a salt removal rate of 0.1% or more higher than that when the step of modifying the polyamide activation layer is not performed. A water treatment module comprising at least one water treatment separator according to claim 9.

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