KR20190048996A - Method for manufacturing water treatment module and water treatment module prepared by thereof - Google Patents

Abstract

The present specification discloses a post-treatment solution comprising an epoxy compound having two or more epoxy groups, a porous support; And a reverse osmosis membrane including a polyamide active layer provided on the porous support in a raw water supply direction to react the amine group of the polyamide active layer with an epoxy group of the epoxy compound to form a membrane The present invention also provides a method for manufacturing a water treatment module including the step and a water treatment module manufactured by the manufacturing method.

Description

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

The present disclosure relates to a method of manufacturing a water treatment module and a water treatment module manufactured thereby.

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.

A typical example of such a reverse osmosis membrane is a polyamide-based reverse osmosis membrane, and a polyamide-based reverse osmosis membrane is manufactured by a method of forming a polyamide active layer on a microporous layer support. More specifically, And the microporous support is immersed in an aqueous solution of m-phenylenediamine (m-PD) to form an m-PD layer, which is then reacted with tri-mesoyl chloride , TMC) in an organic solvent to bring the m-PD layer into contact with TMC to perform interfacial polymerization, thereby forming a polyamide layer.

Studies on improving the performance of such reverse osmosis membranes have been continuously carried out.

Roh et al., J. Poly. Sci. 36, 1821-1830, 1998

The present disclosure relates to a method of manufacturing a water treatment module and a water treatment module manufactured thereby.

One embodiment of the present disclosure relates to a process for preparing a post-treatment solution comprising an epoxy compound having two or more epoxy groups, And a reverse osmosis membrane including a polyamide active layer provided on the porous support in a raw water supply direction to react the amine group of the polyamide active layer with an epoxy group of the epoxy compound to form a membrane The present invention also provides a method of manufacturing a water treatment module.

One embodiment of the present disclosure provides a water treatment module manufactured according to the method of manufacturing the water treatment module described above.

In addition, one embodiment of the present disclosure provides a water treatment apparatus comprising at least one water treatment module as described above.

The water treatment module manufactured by the manufacturing method of the water treatment module described in this specification has an effect of improving the salt removal rate and decreasing the amount of change in the salt removal rate before and after the water washing process.

1 illustrates a reverse osmosis membrane according to an embodiment of the present invention.
2 shows a water treatment module 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 specification unless specifically stated otherwise.

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

One embodiment of the present disclosure relates to a process for preparing a post-treatment solution comprising an epoxy compound having two or more epoxy groups, And a reverse osmosis membrane including a polyamide active layer provided on the porous support in a raw water supply direction to react the amine group of the polyamide active layer with an epoxy group of the epoxy compound to form a membrane The present invention also provides a method of manufacturing a water treatment module.

In the case of manufacturing the water treatment module by the manufacturing method of the water treatment module according to one embodiment of the present invention, it is possible to form a film with a necessary thickness in a necessary portion, and to efficiently control the water treatment module.

The water treatment module manufactured by the manufacturing method of the water treatment module described in the present specification can improve the salt removal rate of the water treatment module by forming a film by flowing the post treatment solution by flowing the post treatment solution in a state where the module is used, The amount of change in the salt removal rate can be made small.

The post treatment with the solution containing the epoxy compound before the water treatment module was formed was mainly used to prevent the contaminant accumulation on the surface of the reverse osmosis membrane. When a solution containing an epoxy compound is flowed directly onto the reverse osmosis membrane polyamide active layer before the water treatment module is formed, the entire surface of the reverse osmosis membrane is formed with a solution containing the epoxy compound. This makes it impossible to contact only a certain thickness or a certain position of the reverse osmosis membrane. Therefore, there is a disadvantage in that it is not possible to adjust the thickness only to a necessary part of the reverse osmosis membrane differently, or to contact the post-treatment solution only in a required part, thereby forming a film.

In one embodiment of the present invention, the epoxy compound having two or more epoxy groups may be represented by the following general formula (1).

[Chemical Formula 1]

In Formula 1,

n is an integer of 1 to 43; Also preferably, n may be 9.

In one embodiment of the present invention, the epoxy compound may be polyethylene glycol diglycidyl ether (PEGDE).

In one embodiment of the present invention, the molecular weight of the polyethylene glycol diglycidyl ether (PEGDE) is 500 to 2000.

At least one reverse osmosis membrane contained in the water treatment module has a polyamide active layer formed by interfacial polymerization. After the reaction of the interfacial polymerization, an amine group or a carboxyl group may remain in the reverse osmosis membrane. In the water treatment module according to one embodiment of the present invention, an amine group of the polyamide active layer reacts with an epoxy group of the epoxy compound to form a bond by flowing a post-treatment solution containing an epoxy compound into a water treatment module. As the bond is formed, the epoxy group may be opened and an alcohol group may be formed.

In one embodiment of the present invention, the amine group of the polyamide active layer and the epoxy group of the epoxy compound form a bond, so that the chain of the polyamide polymer contained in the polyamide active layer of the at least one reverse osmosis membrane contained in the existing water treatment module chain length becomes longer. As a result, by increasing the chain length, it can be more effective for salt removal.

In addition, since the alcohol group is formed by the bonding, hydrophilicity can be obtained, and fouling of the water treatment module can be suppressed. The epoxy group remaining unreacted with the remaining amine groups is covalently bonded to the unreacted portion of the polyamide active layer, and a stable film can be realized.

In one embodiment of the present invention, the step of forming the film comprises: reacting the amine group of the polyamide active layer with the epoxy group of the epoxy compound to form a polymer comprising a unit of the following formula (2) Wherein the water treatment module comprises a water treatment module.

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

N is an integer of 1 to 43, and p is an integer of 1 to 1,000.

Another embodiment of the present disclosure provides a process for preparing a water treatment module, wherein the polymer comprises units of formula (2), or a compound of formula (3) or (4).

According to one embodiment of the present invention, the epoxy compound may be 0.01 to 1.0% by weight, preferably 0.01 to 0.5% by weight, more preferably 0.1% by weight based on the total weight of the post-treatment solution. When the content of the epoxy compound is within the above range, the amine group of the polyamide active layer and the epoxy compound may be effectively coupled by the epoxy group reaction. If the content of the epoxy compound is less than 0.01% by weight, the epoxy group content is too small and the coupling reaction can not be performed well. If the epoxy compound content is 1.0% by weight or more, the permeation flow rate can be remarkably reduced due to contamination of the RO.

In one embodiment of the present invention, the post-treatment solution may further include deionized water. The deionized water means water in which dissolved ions are completely removed.

In one embodiment of the present disclosure, the step of forming the membrane may comprise the step of forming the post-treatment solution in the porous support; And a reverse osmosis membrane including a polyamide active layer provided on the porous support, for 5 to 15 minutes, preferably 9 to 11 minutes, in a raw water introduction direction. When the time for flowing the post-treatment solution into the water treatment module is within the above-mentioned range, the binding due to the reaction between the residual amine group and the epoxy compound may be effective. If the time is less than 5 minutes, the reaction time is short and the reaction can not be coupled well. If the time is longer than 15 minutes, the permeation flow rate can be remarkably reduced due to the possibility of contamination of the RO membrane.

According to one embodiment of the present disclosure, the step of forming the membrane may comprise the steps of: contacting the post-treatment solution with the porous support; And a reverse osmosis membrane comprising a polyamide active layer disposed on the porous support, at a pressure of 15 psi to 25 psi, preferably 18 psi to 22 psi, in the direction of raw water introduction. If the pressure is less than 15 psi, the post-treatment solution containing the epoxy compound can not uniformly contact the water treatment module. If the pressure exceeds 25 psi, the durability of the water treatment module may become problematic due to the high pressure.

In one embodiment of the present invention, the water treatment module of the present invention is characterized by having a salt removal rate of 99.80% or more before the water washing process under the conditions of a 2,000 ppm NaCl aqueous solution, a pressure of 225 psi, and a temperature of 25 ° C. Specifically, the salt removal rate is 99.80% to 99.86%.

In one embodiment of the present invention, after the post-treatment solution containing the epoxy compound is poured into the water treatment module and then washed with deionized water, the salt removal rate is measured at 2,000 ppm NaCl aqueous solution, 99.70% or more. Specifically, the salt removal rate is 99.70% to 99.76%.

In one embodiment of the present invention, the amount of change in the salt removal rate before and after the step of washing with the deionized water after flowing the post-treatment solution containing the epoxy compound into the water treatment module is 0.15% or less, The change amount of the removal rate is not large and it can have excellent performance. Specifically, the amount of change in the salt removal rate is 0.08% to 0.15%.

One embodiment of the present invention relates to a method of manufacturing a water treatment module including at least one reverse osmosis membrane, a water treatment module, and a water treatment apparatus, but the reverse osmosis membrane constituting the water treatment module may be formed by a method described later.

Wherein the reverse osmosis membrane comprises a porous support; And a polyamide active layer provided on the porous support.

Wherein the polyamide active layer comprises: forming an aqueous solution layer containing an amine compound on a porous support; And forming a polyamide active layer on the aqueous solution layer containing the amine compound.

As the porous support, a coating layer of a polymer material formed on a nonwoven fabric may be used. 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.

Upon contact between the amine compound and the acyl halide compound, 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 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 can form 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.

In the aqueous solution containing the amine compound, the amine compound is not limited as long as it is an amine compound used for preparing a reverse osmosis membrane, and specific examples thereof include m-phenylenediamine, p-phenylenediamine, -Benzene triamine, 4-chloro-1,3-phenylenediamine, 2-chloro-1,4-phenylenediamine or a mixture thereof.

The polyamide active layer can be produced by coating a solution containing an amine compound on a porous polymer layer, and further, by interfacial polymerization by contacting a solution containing an acyl halide compound.

The content of the amine compound may be 0.1 wt% or more and 20 wt% or less based on the solution containing the amine compound.

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 And a mixture of two or more selected from the group consisting of chlorides. The content of the acyl halide compound may be 0.05% by weight or more and 1% by weight or less based on the solution containing the acyl halide compound.

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).

The reverse osmosis membrane may be used as a microfiltration membrane, an ultrafiltration membrane, a nano filtration membrane or a reverse osmosis membrane, and may be used as a reverse osmosis membrane.

One embodiment of the present disclosure provides a water treatment module comprising at least one reverse osmosis 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 above-described reverse osmosis membrane, other configurations and manufacturing methods are not particularly limited, and general means known in the art can be employed without limitation.

1 shows a water treatment separator according to an embodiment of the present invention. 1 illustrates a water treatment separation membrane in which a nonwoven fabric 100, a porous support 200 and a polyamide active layer 300 are sequentially provided. 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.

2 shows a water treatment module according to an embodiment of the present invention. Specifically, if the raw water is flowed in the raw water introduction direction into the water treatment module, water treatment proceeds by the first reverse osmosis membrane (30) and the second reverse osmosis membrane (40) included in the water treatment module. The raw water flows into the housing 10 through the inlet of the end cap 50 located at one end of the housing 10 and the raw water flows through the first reverse osmosis membrane 30 and the second reverse osmosis membrane 40, And only the purified water flows into the space formed on the outer surface of the tube 20. The inflowed purified water is discharged in the purified water discharging direction through the discharge port which is opened to one side of the tube (20). The concentrated water not filtered through the first reverse osmosis membrane 30 and the second reverse osmosis membrane 40 is discharged through the outlet of the end cap 50 located at the other end of the housing 10.

According to one embodiment of the present invention, if a post-treatment solution containing an epoxy compound having two or more epoxy groups in the raw water introduction direction is caused to flow in the water treatment module, the first reverse osmosis membrane (30) The amine groups of the polyamide active layer remaining in the reverse osmosis membrane 40 and the epoxy groups of the epoxy compound contained in the post-treatment solution react with each other to form a bond. The epoxy group may be opened while forming the bond, and an alcohol group may be formed. In this case, before the reaction with the amine group of the polyamide active layer and the epoxy compound contained in the post-treatment solution remaining unresponsive to the first reverse osmosis membrane (30) or the second reverse osmosis membrane (40) By increasing the chain length of the polymer after formation of the bond, it can be more effective for salt removal.

Therefore, even if a separate membrane is not formed in the water treatment membrane before formation of the water treatment module, it is possible to improve the salt removal performance of the reverse osmosis membrane by forming a membrane having a necessary thickness only in a necessary portion in a state where the water treatment module is used, The amount of change in the salt removal rate before and after can also be reduced.

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 into 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.

Comparative Example 1

A reverse osmosis membrane having a polyamide active layer formed by interfacial polymerization of m-phenylenediamine (m-PD) and trimethoyl chloride (TMC) on a porous support was prepared.

A post-treatment solution was prepared by dissolving 0.1 wt% of polyethylene glycol diglycidyl ether (PEGDE, diglycidyl ether) (avg MW = 500) relative to the weight of the entire aqueous solution in deionized water at 25 ° C .

The reverse osmosis membrane was brought into contact with the container containing the post-treatment solution by dipping.

After passing through the post-treatment solution, the reverse osmosis membrane was washed with deionized water to remove residual compounds and dried in an oven.

After that, a circular cylindrical water treatment module was manufactured by rolling multiple layers of reverse osmosis membrane.

Example 1

A round cylindrical water treatment module having a diameter of 8 inches and a length of 40 in was manufactured by rolling several layers without post-treating the reverse osmosis membrane prepared in Comparative Example 1 as a post-treatment solution.

The manufactured cylindrical water treatment module was mounted on a wet skid, and then deionized water was poured through the raw water input path for 30 minutes to remove residual compounds in the module. Thereafter, the charged deionized water was discharged.

Thereafter, 0.1 wt% of polyethylene glycol diglycidyl ether (PEGDE) (avg MW = 500) relative to the weight of the entire aqueous solution was dissolved in deionized water at 25 ° C to prepare a post-treatment solution .

The post-treatment solution was flowed into the water treatment module in the direction of the raw water supply. In this case, the raw water pressure was kept not more than 20 psi. The concentrated water not filtered by the reverse osmosis membrane included in the water treatment module was disposed through the end cap located at the end of the housing of the water treatment module so as not to join with the post treatment solution introduced into the water treatment module.

After the post-treatment solution was poured into the water treatment module in the direction of the raw water for 10 minutes, the flow was stopped and the module was washed with deionized water to remove residual compounds in the water treatment module to prepare a water treatment module.

Example  2

In the same manner as in Example 1 except that the polyethylene glycol diglycidyl ether (PEGDE) (avg MW = 500) was changed to 0.01 weight% in Example 1, Module.

Example  3

In the same manner as in Example 1 except that the amount of the polyethylene glycol diglycidyl ether (PEGDE) (avg MW = 500) was changed to 0.5 weight% in Example 1, Module.

The operating pressures of the water treatment modules prepared according to Examples 1 to 3 were measured to be up to 600 psi.

Experimental Example

The performance of the water treatment modules manufactured according to the above Examples and Comparative Examples was evaluated at 25 ° C and 225 psi using a salt water containing 2,000 ppm of NaCl in the BW R 400 product.

The salt removal rate was measured by measuring the conductivity difference between the purified water and the raw water, and the flux (flux) was calculated by measuring the volume of the purified water secured per unit time (5 minutes).

The amount of change in the salt removal rate before and after the water washing process is described by subtracting the salt removal ratio (%) before the water washing process from the salt removal ratio (%) after the water washing process.

In addition, the change (%) of the permeation flow rate before and after the washing process was calculated by the following formula (1).

The performance of the water treatment modules according to the examples and the comparative examples thus measured is shown in Table 1 below.

PEGDE  Concentration (wt%) Before / after washing process Salt Removal Rate (%) Change in Salt Removal Rate Permeate flow (GFD) Change of permeate flow rate % ) Example  One 0.1 I'm 99.84 -0.08 9,134 +22.6 after 99.76 11,197 Example  2 0.01 I'm 99.80 -0.10 10,133 +19.8 after 99.70 12,141 Example  3 0.5 I'm 99.86 -0.15 8,627 +28.6 after 99.71 11,069 Comparative Example  One 0.1 I'm 99.79 -0.12 10,503 + 20.3% after 99.67 12,633

The GFD of the permeate flow rate means gallon / ft ² · day.

According to Table 1, it can be confirmed that the water treatment modules according to Examples 1 to 3 have a higher salt removal rate than the water treatment module according to Comparative Example 1. [ It is also understood that the value of the amount of change in salt removal rate before and after the water washing process of the water treatment module according to Examples 1 and 2 is smaller than that of Comparative Example 1.

According to Examples 1 to 3, when the post-treatment solution containing an epoxy compound having two or more epoxy groups is flowed in the water treatment module, the amine group of the polyamide active layer and the epoxy group of the epoxy compound react with each other to form a bond It is found that the salt removal ratio is improved and the amount of change in the salt removal rate before and after the water washing process is smaller or smaller than that of Comparative Example 1. [

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. .

10: Housing
20: tube
30: First reverse osmosis membrane
40: Second reverse osmosis membrane
50: end cap
100: Nonwoven fabric
200: Porous support
300: polyamide active layer
400: brine
500: Purified water
600: concentrated water

Claims (12)

A post-treatment solution comprising an epoxy compound having at least two epoxy groups, comprising: a porous support; And a reverse osmosis membrane including a polyamide active layer provided on the porous support in a raw water supply direction to react the amine group of the polyamide active layer with an epoxy group of the epoxy compound to form a membrane ≪ / RTI > The method according to claim 1, wherein the epoxy compound having two or more epoxy groups is represented by the following formula (1):
[Chemical Formula 1]

In the general formula (1), n is an integer of 1 to 43. The method according to claim 1, wherein the epoxy compound is polyethylene glycol diglycidyl ether (PEGDE). [2] The method according to claim 1, wherein the step of forming the film comprises reacting an amine group of the polyamide active layer with an epoxy group of the epoxy compound to form an alcohol group. The method according to claim 1, wherein the step of forming the film comprises reacting an amine group of the polyamide active layer with an epoxy group of the epoxy compound to form a polymer comprising a unit of the following formula (2) The method comprising:
(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the general formulas (2) to (5), n is an integer of 1 to 43, and p is an integer of 1 to 1000. [2] The method according to claim 1, wherein the epoxy compound is contained in an amount of 0.01 to 1.0% by weight based on the total weight of the post-treatment solution. The method of claim 1, wherein the post-treatment solution further comprises deionized water. 2. The method of claim 1, wherein the forming the membrane comprises: contacting the post-treatment solution with the porous support; And a reverse osmosis membrane including a polyamide active layer provided on the porous support, in a raw water feed direction for 5 to 15 minutes. 2. The method of claim 1, wherein the forming the membrane comprises: contacting the post-treatment solution with the porous support; And a reverse osmosis membrane comprising a polyamide active layer disposed on the porous support at a pressure of 15 psi to 25 psi in a raw water feed direction. The method of claim 1, further comprising the step of washing with deionized water after the step of forming the membrane. A water treatment module manufactured according to any one of claims 1 to 10. A water treatment apparatus comprising at least one water treatment module of claim 11.

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