KR20220013744A - Method for manufacturing water treatment membrane, water treatment membrane, and water treatment module - Google Patents

Abstract

The present specification provides a method for manufacturing a water treatment separator, a water treatment separator, and a water treatment module. The method includes the steps of: preparing a first porous support; forming a porous layer; and forming an active layer on the porous layer. The present specification can improve a permeation flow.

Description

Manufacturing method of water treatment separation membrane, water treatment separation membrane and water treatment module

The present specification relates to a method for manufacturing a water treatment separation membrane, a water treatment separation membrane, and a water treatment module.

A representative example of a water treatment separation membrane is a reverse osmosis membrane. Osmosis is a phenomenon in which the solvent moves through the separation membrane from a solution with a low solute concentration to a solution with a high solute concentration between two solutions separated by a semipermeable membrane. is called osmotic pressure. However, when an external pressure higher than the osmotic pressure is applied, the solvent moves toward the solution with a low solute concentration, which is called reverse osmosis. Using the reverse osmosis principle, various salts or organic substances can be separated through the semi-permeable membrane by using the pressure gradient as a driving force. Reverse osmosis membrane using this reverse osmosis phenomenon is used to supply water for home, construction, and industrial use by separating substances at the molecular level and removing salt from salt water or seawater.

A typical example of such a reverse osmosis membrane is a polyamide-based water treatment membrane, and the polyamide-based water treatment membrane is manufactured by forming a polyamide active layer on a microporous layer support. More specifically, polysulfide on a nonwoven fabric A phone layer is formed to form a microporous support, and the microporous support is immersed in an aqueous solution of m-Phenylene Diamine (mPD) to form an mPD layer, which is again trimesoyl chloride (TriMesoyl Chloride, TMC). ) is produced by a method of forming a polyamide layer by interfacial polymerization of the mPD layer with TMC by immersion in an organic solvent.

The permeation flow rate and salt removal rate of the reverse osmosis membrane are used as important indicators of membrane performance, and the development of a method for improving the performance of the reverse osmosis membrane is continuously required.

Korean Patent Publication 10-2015-001647

The present specification relates to a method for manufacturing a water treatment separation membrane, a water treatment separation membrane, and a water treatment module.

An exemplary embodiment of the present specification comprises the steps of preparing a first porous support;

A composition for forming a second porous support at 33° C. or higher and 40° C. or less is applied on the first porous support to form a second porous support, thereby forming a porous layer comprising the first porous support and the second porous support. to do; and

It provides a method of manufacturing a water treatment separation membrane comprising the step of forming an active layer on the porous layer.

An exemplary embodiment of the present specification is a water treatment membrane prepared by the method for producing a water treatment membrane, and the permeate flow rate measured under 2,000 ppm NaCl aqueous solution, pressure 150 psi, temperature 25° C., and 4 L/min conditions is 14.5 GFD or more. provides

In addition, an exemplary embodiment of the present specification provides a water treatment module including one or more of the above-described water treatment separation membrane.

When a reverse osmosis membrane is manufactured using the composition for forming an active layer of a reverse osmosis membrane according to an exemplary embodiment of the present specification, there is an effect of improving the permeation flow rate while maintaining the salt removal rate of the reverse osmosis membrane.

1 illustrates a water treatment separation membrane according to an exemplary embodiment of the present specification.
Figure 2 shows a water treatment module according to an embodiment of the present specification.

In the present specification, when a member is said to be located “on” another member, this includes not only a case in which a member is in contact with another member but also a case in which another member is present between the two members.

In the present specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

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

An exemplary embodiment of the present specification comprises the steps of preparing a first porous support; A composition for forming a second porous support at 33° C. or higher and 40° C. or less is applied on the first porous support to form a second porous support, thereby forming a porous layer comprising the first porous support and the second porous support. to do; and forming an active layer on the porous layer.

Among the factors that can evaluate the performance of a water treatment membrane, the permeate flow rate and the salt removal rate generally have a trade-off relationship. Therefore, it is important to improve the permeate flow rate while minimizing the reduction in the existing salt removal rate when developing a water treatment membrane.

In the case of the manufacturing method of the water treatment separation membrane according to the present specification, when the porous layer included in the water treatment separation membrane is manufactured, the temperature of the composition for forming the second porous support is maintained at a temperature of 33°C or more and 40°C or less higher than room temperature, By lowering the viscosity of the composition for forming the second porous support, the amount of the composition for forming the second porous support adsorbed to the first porous support may be increased. Accordingly, the first porous support may have uniform pores, and the water treatment separation membrane including the porous layer including the first porous support may improve the permeation flow rate. In the present specification, room temperature may mean 20 ± 5 °C.

In an exemplary embodiment of the present specification, the composition for forming the second porous support is 33° C. or more and 38° C. or less. When the composition for forming the second porous support is less than 33° C., the effect of improving the permeation flow rate of the water treatment separation membrane cannot be confirmed, and when it exceeds 40° C., defects occur on the surface of the prepared porous layer, and an active layer can be formed none.

The temperature of the composition for forming the second porous support may be measured with a thermometer by putting the composition for forming the second porous support into a solution storage tank, or may be measured with a temperature sensor installed in the solution storage tank. The solution storage tank and the thermometer are not particularly limited, and those applied in the art may be appropriately employed.

In an exemplary embodiment of the present specification, the viscosity of the composition for forming the second porous support may be 0.45 Pa·s to 0.5 Pa·s.

When the viscosity of the composition for forming the second porous support satisfies the above range, when the composition for forming the second porous support is applied and adsorbed on the first porous support, the first porous support has uniform pores This can improve the performance of the water treatment separation membrane.

The viscosity of the composition for forming the second porous support may be adjusted according to the above-described temperature range, the content of polysulfone included in the composition for forming the second porous support, and the weight average molecular weight of the polysulfone.

The viscosity can be measured by sweeping the shear rate with a viscometer. The viscosity measuring device is not limited, and any device applied in the art may be appropriately employed.

In one embodiment of the present specification, the composition for forming the second porous support includes polysulfone and a solvent.

The polysulfone may have a weight average molecular weight of 1x10 ⁵ g/mol to 2x10 ⁵ g/mol. When the polysulfone satisfies the aforementioned weight average molecular weight range, the viscosity range of the composition for forming the second porous support may be satisfied.

The solvent may be dimethylformamide (DMF), but is not limited thereto.

In an exemplary embodiment of the present specification, the polysulfone is included in an amount of 15 to 20 parts by weight based on 100 parts by weight of the composition for forming the second porous support.

When the polysulfone is included in the composition for forming the second porous support in the above-described weight part range, the second porous support having a desired thickness can be prepared with the composition for forming the second porous support. have.

In one embodiment of the present specification, the step of forming the active layer on the porous layer is by interfacial polymerization of an organic solution containing an acyl halide compound and an aqueous solution containing an amine compound.

According to an exemplary embodiment of the present specification, the acyl halide compound is not particularly limited, but for example, an aromatic compound having 2 to 3 carboxylic acid halides, trimesoyl chloride (TMC), isophthalo It may be one or more mixtures selected from the group consisting of monochloride, terephthaloyl chloride, and mixtures thereof. Preferably, the acyl halide compound is trimesoyl chloride (TMC).

According to an exemplary embodiment of the present specification, the content of the acyl halide compound may be 0.02 wt% to 1 wt%, preferably 0.08 wt% to 0.6 wt%, based on the total weight of the organic solution containing the acyl halide compound. . When the content of the acyl halide compound satisfies the above range, a water treatment separation membrane having the salt removal rate and permeate flow rate desired in the present specification may be manufactured.

In addition, according to an exemplary embodiment of the present specification, the organic solution containing the acyl halide compound may further include an organic solvent, and the organic solvent is an aliphatic hydrocarbon solvent, for example, freons and 5 to carbon atoms. Hydrophobic liquids that are immiscible with water such as hexane, cyclohexane, heptane, and alkanes containing 12 (Exxon), IsoPar G, etc. may be used, but is not limited thereto. Preferably, the organic solvent may be IsoPar G.

According to an exemplary embodiment of the present specification, if the amine compound in the aqueous solution containing the amine compound is an aromatic amine compound used for manufacturing a water treatment separation membrane, the type is not limited, but for a specific example, m-phenylenediamine (mPD ), from the group consisting of p-phenylenediamine, 1,2,4-benzenetriamine, 4-chloro-1,3-phenylenediamine, 2-chloro-1,4-phenylenediamine, and mixtures thereof. It may be one or more selected. Specifically, m-phenylenediamine (mPD) is preferable.

According to an exemplary embodiment of the present specification, the solvent of the aqueous solution containing the amine compound may be water, and the remainder excluding the amine compound in the aqueous solution containing the amine compound may be water.

According to an exemplary embodiment of the present specification, based on the total weight of the aqueous solution containing the amine compound, the content of the amine compound may be 0.001 wt% to 10 wt%, preferably 0.1 wt% to 7 wt%. When the above content is satisfied, a water treatment separation membrane having a desired level of removal rate and flow rate may be manufactured.

When the aqueous solution containing the amine compound and the organic solution containing the acyl halide compound are brought into contact, the amine compound coated on the surface of the porous layer and the acyl halide compound react to form polyamide through interfacial polymerization, and the porous layer It is adsorbed to the layer to form a thin film. In the contacting method, the active layer may be formed through a method such as dipping, spraying, or coating.

The aqueous solution containing the amine compound may further include a basic acid acceptor, if necessary. The basic acid acceptor may be, for example, a trialkylamine compound, specifically, triethyleneaminecamphorsulfonic acid, but is not limited thereto. The basic acid acceptor may be included in an amount of 1 wt% to 10 wt% based on the total weight of the aqueous solution containing the amine compound.

In an exemplary embodiment of the present specification, the method may further include washing the active layer formed on the porous layer with water after the step of forming the active layer on the porous layer.

The washing with water specifically refers to a process of rinsing with water at a temperature of 60° C. for 10 minutes.

By performing the washing with water as described above, residues that did not participate in the reaction for forming the active layer may be removed.

In the present specification, the porous layer includes a first porous support and a second porous support.

In one embodiment of the present specification, a nonwoven fabric may be used as the first porous support. Polyester may be used as the material of the nonwoven fabric, but is not limited thereto.

The thickness of the nonwoven fabric may be 50 μm to 150 μm, but is not limited thereto. Preferably, the thickness may be 80 μm to 120 μm. When the thickness of the nonwoven fabric satisfies the above range, durability of the gas separation membrane including the porous layer may be maintained.

The second porous support may mean that a coating layer of the composition for forming the second porous support is formed on the first porous support.

The thickness of the second porous support may be 30 μm to 60 μm, but is not limited thereto. Preferably, the thickness may be 30 μm to 50 μm. When the thickness of the coating layer satisfies the above range, the durability of the water treatment separation membrane including the porous layer including the second porous support may be properly maintained.

The composition for forming the second porous support may be a homogeneous liquid obtained after dissolving polysulfone solids in a solvent dimethylformamide at 80° C. to 85° C. for 12 hours.

The second porous support may be formed by a method of casting. The casting refers to a solution casting method, and specifically, it may refer to a method of dissolving the polymer material in a solvent, developing it on a smooth surface without adhesiveness, and then replacing the solvent. Specifically, the method of substituting the solvent may use a nonsolvent induced phase separation method. In the non-solvent induced phase separation method, a polymer is dissolved in a solvent to make a homogeneous solution, molded into a predetermined shape, and then immersed in a non-solvent. Thereafter, the non-solvent and the solvent are interchanged by diffusion, and the composition of the polymer solution is changed, and the polymer is precipitated.

In an exemplary embodiment of the present specification, the method may further include preparing a protective layer on the active layer after the step of preparing the active layer.

Components, manufacturing methods, manufacturing conditions, etc. of the protective layer may be employed without limitation those applied in the art.

According to an example, the protective layer may be prepared by applying a composition for forming a protective layer on the active layer. If necessary, after the composition for forming a protective layer is applied, the excess aqueous solution is removed using an air knife, and drying at 85° C. may be further performed.

The composition for forming the protective layer may be an aqueous solution containing polyvinyl alcohol. Specifically, based on the total weight of the composition for forming a protective layer, the polyvinyl alcohol may be included in an amount of 1 wt% to 10 wt%, and the remainder of the solvent may be included.

The solvent may be water, but is not limited thereto.

In the present specification, the water treatment separation membrane may be used as a micro filtration membrane, an ultra filtration membrane, a nano filtration membrane, or a reverse osmosis membrane, and specifically may be used as a reverse osmosis membrane. .

In an exemplary embodiment of the present specification, as a water treatment separation membrane prepared by the above-described method for producing a water treatment separation membrane, the permeate flow rate measured under the conditions of 2,000 ppm NaCl aqueous solution, pressure 150 psi, temperature 25° C., and 4 L/min is 14.5 GFD or more.

The permeate flow rate is preferably 14.5 GFD or more and 17 GFD or less. The permeate flow rate is more preferably between 14.97 GFD and 16.44 GFD.

In an exemplary embodiment of the present specification, as a water treatment separation membrane prepared by the above-described water treatment separation membrane manufacturing method, the salt removal rate measured under the conditions of 2,000 ppm NaCl aqueous solution, pressure 150 psi, temperature 25° C., and 4 L/min is 99.7% or more.

The salt removal rate is preferably 99.7% or more and 99.9%, more preferably 99.77% to 99.81%.

An exemplary embodiment of the present specification provides a water treatment module including one or more of the water treatment separation membrane.

The number of water treatment separation membranes included in the water treatment module may be 1 to 50, 1 to 30, and preferably 24 to 28, but is not limited thereto.

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 water treatment separation membrane, other configurations and manufacturing methods are not particularly limited, and general means known in this field may be employed without limitation.

1 illustrates a water treatment separation membrane according to an exemplary embodiment of the present specification. Specifically, FIG. 1 shows a water treatment separation membrane sequentially provided with a porous layer and an active layer 300 including a first porous support 100 and a second porous support 200, and brine ( 400) is introduced, the purified water 500 is discharged through the nonwoven fabric 100, and the concentrated water 600 does not pass through the active layer 300 and is discharged to the outside. The water treatment separation membrane according to an exemplary embodiment of the present specification is not limited to the structure of FIG. 1 , and additional components may be further included.

Figure 2 shows a water treatment module according to an embodiment of the present specification. Specifically, the water treatment module is configured to include a central tube 40 , a feed spacer 20 , a reverse osmosis membrane 10 , a tricot filtration channel 30 , and the like. When raw water flows into the water treatment module, the raw water flows in through the supply spacer 20 in the water treatment module. One or more water treatment separation membranes 10 extend outwardly from the tube 40 and are wound around the tube 40 . The supply spacer 20 forms a passage through which raw water is introduced from the outside, and serves to maintain a gap between one water treatment separation membrane 10 and the other water treatment separation membrane 10 . To this end, the supply spacer 20 is in contact with one or more water treatment separation membranes 10 from the upper and lower sides, and is wound around the tube 40 . The tricot filtration water channel 30 generally has a structure in the form of a fabric, and serves as a channel for creating a space through which purified water can flow through the water treatment separation membrane 10 . The tube 4 is located at the center of the water treatment module, and serves as a passage through which filtered water is introduced and discharged. At this time, it is preferable that pores of a predetermined size are formed on the outside of the tube 40 so that filtered water is introduced, and at least one is preferably formed. Since the water treatment separation membrane 10 is manufactured by the above manufacturing method, it is possible to have excellent permeate flow performance without reducing the salt removal rate.

Hereinafter, this In order to describe the specification in detail, it will be described in detail with reference to examples. However, the embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present specification to those of ordinary skill in the art.

production example

Example 1.

(Preparation of porous layer)

A nonwoven fabric was used as the first porous support, the nonwoven fabric was polyester, and the polyester had a thickness of 90 μm.

In order to prepare a second porous support on the first porous support, a composition for forming a second porous support was prepared. The composition for forming the second porous support is based on the total weight of the composition for forming the second porous support, 17% by weight of polysulfone solid is added to 83% by weight of the solvent dimethylformamide (DMF) and 80° C. It was a homogeneous liquid obtained after dissolving at 85° C. for 12 hours. This was put into a solution storage tank and maintained at 33°C. The solution storage tank includes a jacket for maintaining the temperature of the solution, and by flowing hot or cold water into the jacket, it was possible to maintain a desired temperature of the solution. The temperature of the solution was measured from a thermometer installed inside the storage tank.

Thereafter, the composition for forming the second porous support at 33° C. was cast at a thickness of 40 μm on the first porous support (polyester) by a slot die coating method to prepare a second porous support.

Then, the cast nonwoven fabric was placed in water to prepare a porous layer including the first porous support and the second porous support.

(Preparation of active layer)

In order to prepare an active layer on the porous layer, an aqueous solution containing an amine compound was prepared. The aqueous solution containing the amine compound was prepared by including 0.4 wt% of metaphenylenediamine (mPD) and the remainder of water based on the total weight of the aqueous solution containing the amine compound.

Then, the prepared aqueous solution containing the amine compound was applied on the porous layer to form an aqueous solution layer. Furthermore, the excess aqueous solution generated during application was removed using an air knife.

An organic solution containing an acyl halide compound was applied on the aqueous layer. The organic solution containing the acyl halide compound was prepared by including trimesoyl chloride (TMC) 0.5% by weight and the remainder of the organic solvent (IsoPar G) based on the total weight of the organic solution containing the acyl halide compound.

Then, after drying at 95° C. until all of the liquid components evaporated, it was washed with ultrapure distilled water (DIW).

(Preparation of protective layer)

After applying an aqueous solution of polyvinyl alcohol, a composition for forming a protective layer, on the surface of the washed separator, remove the excess aqueous solution using an air knife, and dry it at 85°C until all the liquid components evaporate. A final separator was prepared. The composition for forming a protective layer was prepared by including 3 wt % of polyvinyl alcohol and the remainder of water based on the total weight of the composition for forming a protective layer.

Example 2.

In Example 1, a water treatment separation membrane was prepared in the same manner as in Example 1, except that the temperature of the composition for forming the second porous support was maintained at 38°C.

Comparative Examples 1 and 2.

In Example 1, a water treatment separation membrane was prepared in the same manner as in Example 1, except that the temperature of the composition for forming the second porous support was applied as shown in Table 1 below.

Experimental example

Salt Removal Rate and Permeate Flow Measurement

For the separation membranes prepared in Examples and Comparative Examples, the salt removal rate and permeation flow rate were measured in an aqueous solution of 2,000 ppm NaCl at 150 psi.

Specifically, the salt removal rate was calculated by Equation 1 below as the conductivity of the produced water obtained by operating a 2,000 ppm NaCl aqueous solution at 150 psi pressure, 4 LPM flow rate, and 25° C., and is shown in Table 2 below.

[Formula 1]

Salt removal rate (Rejection) (%) = (1-Production water concentration (ppm) / Raw water concentration (ppm)) X 100

The permeation flow rate was measured under the same conditions as the salt removal rate, and the amount of water produced per unit time and unit area was calculated in GFD units (GFD=gallon/ft ² day) and is shown in Table 1 below.

division Temperature (℃) of the composition for forming the second porous support Salt Removal Rate (%) Permeate flow (GFD) Example 1 33 99.81 14.97 Example 2 38 99.77 16.44 Comparative Example 1 26 99.84 13.96 Comparative Example 2 60 Poor appearance of porous layer Comparative Example 3 30 99.81 14.01

According to Table 1, it was confirmed that the water treatment separation membranes of Examples 1 and 2 prepared according to the manufacturing method of the water treatment membrane according to the present specification were superior in permeate flow rate than Comparative Examples 1 and 3. On the other hand, in the case of Comparative Example 2, there was a defect in the surface of the prepared porous layer, so that the active layer could not be formed on the porous layer.

Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and it is possible to carry out various modifications within the scope of the claims and the detailed description of the invention, and this also falls within the scope of the invention. .

10: water treatment membrane
20: supply spacer
30: tricot filtered water
40: tube
100: first porous support
200: second porous support
300: active layer
400: brine
500: purified water
600: concentrated water

Claims (10)

Preparing a first porous support;
A composition for forming a second porous support at a temperature of 33° C. or higher and 40° C. or lower is applied on the first porous support to form a second porous support, thereby forming a porous layer comprising the first porous support and the second porous support. to do; and
A method of manufacturing a water treatment separation membrane comprising the step of forming an active layer on the porous layer. The method according to claim 1, wherein the viscosity of the composition for forming the second porous support is 0.45 Pa·s to 0.5 Pa·s. The method according to claim 1, wherein the composition for forming the second porous support comprises polysulfone and a solvent. The method according to claim 1, wherein the composition for forming the second porous support is 33 °C or more and 38 °C or less. The method of claim 3, wherein the polysulfone is included in an amount of 15 to 20 parts by weight based on 100 parts by weight of the composition for forming the second porous support. The method according to claim 1, wherein the step of forming the active layer on the porous layer is by interfacial polymerization of an organic solution containing an acyl halide compound and an aqueous solution containing an amine compound. The method according to claim 1, further comprising washing the active layer formed on the porous layer with water after the step of forming the active layer on the porous layer. The method according to claim 1, further comprising the step of forming a protective layer on the active layer after the step of forming the active layer on the porous layer. A water treatment separation membrane manufactured by the method for manufacturing a water treatment separation membrane according to any one of claims 1 to 8,
A water treatment separation membrane in which the permeate flow rate measured at 2,000 ppm NaCl aqueous solution, pressure 150psi, temperature 25℃, and 4L/min conditions is 14.5 GFD or more. A water treatment module comprising at least one water treatment separation membrane according to claim 9 .

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