KR20170126693A - Reverse osmosis membrane and method manufacturing same - Google Patents

Abstract

The present invention relates to a reverse osmosis membrane which includes a support and an active layer included on the support, wherein adhesive force between the support and the active layer is not less than 90 gf and not more than 100 gf. The support includes: nonwoven fabric; and a polymer layer including at least one between polysulfone and polyethersulfone included on the nonwoven fabric. The reverse osmosis membrane and the manufacturing method thereof provided by the present invention have improved durability by improving adhesive force between the support and the active layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse osmosis membrane,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse osmosis membrane and a manufacturing method thereof.

The phenomenon that the solvent moves between the two solutions separated by the semi-permeable membrane through the membrane from the solution with a low solute concentration to the solution with a high solute concentration is called osmotic phenomenon. The pressure acting on the solution side Is called osmotic pressure. However, when an external pressure higher than osmotic pressure is applied, the solvent moves toward the solution having a low solute concentration. This phenomenon is called reverse osmosis. By using the reverse osmosis principle, it is possible to separate various salts or organic substances through the semipermeable membrane using the pressure gradient as a driving force. Water treatment membranes using this reverse osmosis phenomenon have been used to supply water for domestic, architectural and industrial purposes by separating substances at a molecular level and removing salts from brine or seawater.

Typical examples of such a water treatment separation membrane include a polyamide-based water treatment separation membrane, and a polyamide-based water treatment separation membrane is manufactured by a method of forming a polyamide active layer on a microporous layer support. More specifically, A polysulfone layer is formed to form a microporous support, and this microporous support is immersed in an aqueous solution of m-phenylene diamine (mPD) to form an mPD layer, which is then reacted with tri- mesoyl chloride , TMC) in an organic solvent to bring the mPD layer into contact with the TMC to perform interfacial polymerization, thereby forming a polyamide layer.

The permeation flux and the salt removal rate in the water treatment membrane are used as an important index indicating the performance of the membrane. Such performance is greatly affected by the active layer of the polyamide structure formed by the interface polymerization method.

Attempts have been made to increase the permeation flow rate with the change of the composition ratio of m-phenylenediamine (mPD) and trimethoyl chloride (TMC) used in the interfacial polymerization, but there is a limit in increasing the permeation flow rate due to such composition change.

Korean Laid-Open Publication No. 10-1999-0019008

The present application aims at providing a reverse osmosis membrane having improved durability by improving adhesion between a support and an active layer, and a method of manufacturing the same.

The present specification discloses a light emitting device comprising a support, and an active layer provided on the support,

Wherein the adhesive force between the support and the active layer is 90 gf or more and 100 gf or less.

In the reverse osmosis membrane according to one embodiment of the present invention, the durability of the reverse osmosis membrane is improved when the adhesive force between the support and the active layer satisfies the above range. In particular, the reverse osmosis membrane satisfying the above adhesive strength range maintains durability in the range of pH 2 to 12, and can maintain the performance of the reverse osmosis membrane such as the salt removal rate.

FIG. 1 illustrates a reverse osmosis membrane according to an embodiment of the present invention.

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

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 specification unless specifically stated otherwise.

An embodiment of the present invention provides a reverse osmosis membrane having a support and an active layer provided on the support, wherein the adhesive force between the support and the active layer is 90 gf or more and 100 gf or less. In one embodiment, the adhesion between the support and the active layer is from 90 gf to 95 gf.

As used herein, the term "adhesive force " means the sticking force between two media. For example, the force that sticks between the support and the active layer of the reverse osmosis membrane described in this specification is called "adhesive force ".

The adhesive force was measured by a method of lamination of a reverse osmosis membrane using a texture analyzer. Specifically, the reverse osmosis membrane was attached to a tape and a PET film, and then the PET film was pulled up at a constant speed in a 180 ° direction to measure a force according to the distance when the separation membrane was laminated.

The inventors of the present invention have found that the durability of the reverse osmosis membrane is improved when the adhesion between the support and the active layer of the reverse osmosis membrane satisfies the above range. In particular, the reverse osmosis membrane satisfying the above adhesive strength range maintains durability in the range of pH 2 to 12, and can maintain the performance of the reverse osmosis membrane such as the salt removal rate.

More specifically, in order to verify the durability of the reverse osmosis membrane, a clean-in-place (CIP) process is generally performed in a pH range of 2 to 12. In this process, the conventional reverse osmosis membrane has a large permeation flow rate . However, since the reverse osmosis membrane according to one embodiment of the present invention has strong adhesive force between the respective layers, the increase in the permeation flow rate after the CIP process is small. That is, the reverse osmosis membrane according to one embodiment of the present invention is excellent in durability.

In the reverse osmosis membrane according to one embodiment of the present invention, the increase in the permeated flux after performing the CIP process is less than 10% before the CIP process.

In one embodiment of the present disclosure, the support comprises a nonwoven fabric; And a polymer layer comprising at least one of polysulfone and polyisocyanate on the nonwoven fabric.

In one embodiment of the present invention, the nonwoven fabric may be those commonly used in the art. According to one embodiment, the amount of polysulfone or polyisocyanate impregnated in the nonwoven fabric may be designed to vary depending on the kind of the nonwoven fabric, for example, the thickness and the degree of porosity of the nonwoven fabric. In one embodiment, the amount of polysulfone and polyisocyanate in the nonwoven may be 0.6 to 3 g / m < ² >.

When the nonwoven fabric within the polysulfone and polyimides seoseol phone amount 0.6 g / m ² or more, it is possible to prevent the durability deterioration when improved adhesion between the active layer and the support, by using this, hayeoteul preparing a reverse osmosis membrane, 3 g / m ² The problem that the salt removal efficiency is lowered in the performance of the reverse osmosis membrane can be prevented.

Wherein the amount of polysulfone and polyisocyanate in the nonwoven fabric is determined by peeling off the polymer layer with a tape in a structure of a porous support including a nonwoven fabric and a polymer layer including at least one of polysulfone and polyisocyanate on the nonwoven fabric , Polysulfone in a nonwoven fabric, and polyisocyanate in a solvent. Here, the conditions for stripping with tape are as follows. The porous support was dried in a vacuum desiccator for 24 hours to remove the polymer layer on the upper surface of the nonwoven fabric, and the tape was peeled off at one time after bonding with the same area as the nonwoven fabric area. This method is effective for peeling off the polymer layer on the upper surface of the nonwoven fabric having weak adhesion, except for polysulfone or polyisocyanate impregnated in the nonwoven fabric.

According to one example, the amount of impregnated polysulfone or polyisocyanate can be adjusted depending on the degree of porosity of the nonwoven fabric. For example, the pore size of the nonwoven fabric can be selected on the average of 5 to 30 μm. The nonwoven fabric may have a thickness of 90 to 110 μm, but the present invention is not limited thereto.

The support may be prepared by applying a composition comprising at least one of polysulfone and polyisocyanate and a solvent onto a nonwoven fabric. Drying or curing can be carried out if necessary. As a coating method, a coating method known in the art such as slot coating can be applied.

For example, the composition may comprise from 10 to 20% by weight of at least one of a polysulfone and a polyisocyanate, and a solvent balance. As the solvent, dimethylformamide, polyethylene glycol and the like can be used.

In this specification, polysulfone and polyisaphyphone are commercially available. For example, polysulfone having a molecular weight of Mw of 125,000 to 130,000 and Mn of 70,000 to 75,000 may be used, and those containing the following structural structural units may be used according to an example.

For example, a polyisophthalon having a molecular weight of Mw of 50,000 to 60,000 may be used. According to one example, those containing the following structural structural units may be used

In one embodiment, the support comprises a nonwoven fabric; And a polymer layer comprising at least one of polysulfone and polyisocyanate on the nonwoven fabric, wherein the amount of polysulfone and polyisocyanate in the support is 0.6 to 3 g / m ² .

Another embodiment of the present disclosure includes a polymeric layer comprising a support and an active layer provided on the support, wherein the support comprises at least one of polysulfone and polyisocyanate, wherein the polysulfone and / Wherein the polyisocyanate amount is 0.6 to 3 g / m ² , and the adhesion between the support and the active layer is 90 gf or more and 100 gf or less.

In one embodiment of the present invention, the active layer may be a polyamide layer.

The active layer may be prepared by coating a solution containing an amine compound on the porous polymer layer, followed by interfacial polymerization by contacting a solution containing an acyl halide compound.

The amine compound is not limited as long as it can be used in the polymerization of polyamide. Specific examples thereof include m-phenylenediamine (mPD), p-phenylenediamine (PPD), 1,3,6-benzenetriamine ), 4-chloro-1,3-phenylenediamine, 6-chloro-1,3-phenylenediamine, 3-chloro-1,4-phenylenediamine or a mixture thereof can be preferably used. The content of the amine compound may be 0.1 wt% or more and 20 wt% or less based on 100 wt% of the solution.

The acyl halide compound is not limited as long as it can be used in the polymerization of polyamides. Specific examples of the acyl halide compound include aromatic compounds having 2 to 3 carboxylic acid halides such as trimethoyl chloride, isophthaloyl chloride and terephthaloyl chloride Or a mixture of two or more thereof. The content of the acyl halide compound may be 0.05 wt% or more and 1 wt% or less based on 100 wt% of the solution.

For example, the solution containing the amine compound may further contain water, acetone, dimethylsulfoxide (DMSO), 1-methyl-2-pyrrolidinone (NMP), hexamethylphosphoramide can do.

For example, the solution containing the acyl halide compound may further include an organic solvent. Examples of the organic solvent include aliphatic hydrocarbon solvents such as Freon and hydrophobic liquids such as hexane, cyclohexane, heptane and alkane having 5 to 12 carbon atoms which are immiscible with water, for example, alkanes having 5 to 12 carbon atoms And mixtures thereof, such as IsoPar (Exxon), ISOL-C (SK Chem), and ISOL-G (Exxon).

In the production of the active layer, when an amine compound and an acyl halide compound are brought into contact with each other, an amine compound and an acyl halide compound react with each other to form a polyamide by interfacial polymerization, and a thin film is formed by being adsorbed on the microporous support. The contact may be made by an immersion, spraying or coating method. As the interfacial polymerization conditions, those known in the art can be used.

The method of forming the active layer using a solution containing an amine compound on the support is not particularly limited. For example, spraying, coating, immersion, dropping, etc. may be used.

The preparation method may further include a step of removing a solution containing an excess amine compound as needed before the amine compound and the acyl halide compound are contacted. When the solution containing the amine compound formed on the porous polymer layer is excessively large, the composition in the solution may be uneven. When the composition in the solution is nonuniform, the non-uniform active layer may be formed by subsequent interfacial polymerization. Therefore, it is preferable to remove the excess solution after forming the solution layer containing the amine compound on the porous support. The removal of the excess solution is not particularly limited, but can be carried out using, for example, a sponge, an air knife, nitrogen gas blowing, natural drying, or a compression roll.

The reverse osmosis membrane may further include an additional layer as needed. For example, the reverse osmosis membrane may further include an anti-fouling layer provided on the active layer.

According to an embodiment of the present invention, there is provided a method of manufacturing a reverse osmosis membrane, comprising: forming an active layer such that an adhesive force between a support and an active layer provided on the support is 90 gf or more and 100 gf or less.

A method of manufacturing a reverse osmosis membrane according to an embodiment of the present invention is characterized in that the support comprises a polymer layer containing at least one of polysulfone and polyisocyanate, and the amount of polysulfone and polyisocyanate in the support is 0.6 to 3 g / m < ^{2 &} gt ;.

One embodiment of the present invention provides a water treatment module including at least one of the above-described reverse osmosis membranes.

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 to illustrate the present invention. 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 above-described embodiments. Embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art.

Hereinafter, the present invention will be described in detail by way of examples with reference to the following examples. However, the following examples are intended to illustrate the present invention and the scope of the present invention is not limited thereto.

Experimental Example : Example  One, Example  2, Comparative Example  1 and Comparative Example  2

A polysulfone layer and a polyamide layer were formed on the nonwoven fabric to prepare a reverse osmosis membrane. Specifically, as Example 1, a reverse osmosis membrane having an adhesive strength of 90 gf or more between the support and the active layer was prepared by controlling the amount of polysulfone impregnated in the nonwoven fabric as described in the following table. As Comparative Examples 1 and 2, Respectively. The salt removal rate and permeate flow rate before and after the Clean-In-Place process were measured using the thus prepared reverse osmosis membrane, and the deviation before CIP process was measured.

The amount of polysulfone impregnated into the nonwoven fabric (g / m ² ) The adhesive force (gf) between the support and the active layer CIP full performance Performance after CIP Deviation Salt removal rate
(%) Permeate flow rate
(GFD) Salt removal rate
(%) Permeate flow rate
(GFD) ? Permeation flow rate Comparative Example 1 0.5 30.26 99.61 30.02 99.67 43.76 46% Comparative Example 2 1.1 48.22 99.59 22.81 99.06 36.07 58% Example 1 2.6 91.84 99.43 24.98 99.55 30.07 20% Example 2 1.93 94.62 99.67 20.90 99.64 23.75 14%

As shown in Table 1, in the case of the reverse osmosis membrane of Examples 1 and 2 in which the adhesive force between the support and the active layer was 90 gf or more, the deviation of the permeation flow rate before and after the CIP process was 20% and 14% And 2, it was confirmed that the reverse osmosis membrane had excellent durability.

Comparative Example  3

A reverse osmosis membrane was prepared in the same manner as in Example 1, except that the amount of polysulfone impregnated in the nonwoven fabric was adjusted to 1.45 g / cm ³ . At this time, the adhesive force between the support and the active layer of the prepared reverse osmosis membrane was measured to be 76.81 gf.

It is generally considered in the art that the reverse osmosis membrane has high durability and high stability when the change in permeation flow rate before and after the CIP process is 25% or less. In the present invention, when the adhesive force between the support and the active layer of the reverse osmosis membrane is 90 gf or more, the change in permeation flow rate is measured within the above range, and the durability of the reverse osmosis membrane is improved. In the case of Comparative Example 3 corresponding to the range of the adhesive force below that, it was predicted that the increase of the permeation flow rate would be larger than that of the reverse osmosis membrane according to the present invention.

1:
2: Support
3: Nonwoven fabric
4: polymer layer containing at least one of polysulfone and polyisocyanate

Claims (7)

A support, and an active layer provided on the support,
Wherein the adhesion between the support and the active layer is 90 gf or more and 100 gf or less. [2] The absorbent article of claim 1, wherein the support comprises: a nonwoven fabric; And a polymer layer comprising at least one of polysulfone and polyisocyanate on the nonwoven fabric. [2] The absorbent article of claim 1, wherein the support comprises: a nonwoven fabric; And a polymer layer comprising at least one of polysulfone and polyisocyanate on the nonwoven fabric, wherein the amount of polysulfone and polyisocyanate in the nonwoven fabric is 0.6 to 3 g / m ² , . The reverse osmosis membrane of claim 1, wherein the active layer is a polyamide layer. And forming an active layer so that the adhesive force between the support and the active layer provided on the support is 90 gf or more and 100 gf or less. [6] The method of claim 5, wherein the support comprises: a nonwoven fabric; And a polymer layer comprising at least one of polysulfone and polyisocyanate on the nonwoven fabric, wherein the amount of polysulfone and polyisocyanate in the support is 0.6 to 3 g / m ² . A water treatment module comprising a reverse osmosis membrane according to any one of claims 1 to 4.

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