KR102595067B1 - Membrane distillation membrane with excellent long-term stability and Manufacturing method thereof - Google Patents

Abstract

The porous separator for the membrane contactor process of the present invention was manufactured by using a copolymer containing fluorine-based repeating units in a specific ratio, thereby improving the hydrophobicity of the separator and having excellent long-term stability. Specifically, the porous separation membrane for the membrane contactor process has the advantage of excellent permeation flux and salt rejection rate, and excellent long-term stability as the above two performances are maintained for a long time.
When the porous separation membrane according to the present invention is applied to a membrane distillation process for seawater desalination, the effectiveness of the separation membrane is maintained for a long period of time, eliminating the need for unnecessary replacement, and improving the efficiency of the process more than before. Additionally, the membrane can be applied not only to the membrane distillation process but also to membranes in various fields that require high hydrophobicity.

Description

Porous separation membrane for membrane contactor process with excellent long-term stability and manufacturing method thereof {Membrane distillation membrane with excellent long-term stability and manufacturing method thereof}

The present invention relates to a porous separation membrane for a membrane contactor process with excellent long-term stability and a method of manufacturing the same. Specifically, the present invention relates to a porous separator for a porous membrane contactor process in which a copolymer with improved hydrophobicity is manufactured and polymer fibers containing the same are accumulated three-dimensionally, and a method for manufacturing the same.

Seawater desalination refers to a type of water treatment process that removes dissolved substances, including salt, from seawater that is difficult to use directly as domestic or industrial water and purifies it into fresh water for high purity drinking water, domestic water, and industrial water. The seawater desalination method includes distillation, reverse osmosis, electro-dialysis, freezing process using cold energy, and membrane distillation using a hydrophobic membrane.

The double membrane distillation method is widely used because it has the advantage of simple operation and the ability to obtain high purity fresh water. Specifically, in the membrane distillation method, the surface tension of the solvent or solute is greater than the surface of the membrane, so it cannot pass through the pores of the membrane in a liquid state and is repelled from the surface of the membrane, and the substance to be separated is phase transformed into a vapor phase at the pore entrance of the surface of the membrane. This is the principle in which fresh water diffuses and permeates into the pores, and ultimately condenses and separates on the other side of the membrane.

In order to further improve the efficiency of the seawater desalination process using the membrane distillation method, the membrane pores must be maintained in a dry state. Specifically, it is desirable to use a porous hydrophobic membrane that has excellent permeation flux and salt rejection, which are membrane performance, and can maintain the pores of the membrane dry for a long time. Examples include PTFE, PP, PVDF, and PVDF-HFP. use. Previous literature Journal of Membrane Science 428 (2013) pp. 104-115 discloses a porous separator for a membrane contactor process using a PVDF-HFP copolymer, but there is a problem in that the separator becomes wet over time during the membrane distillation process with the prepared separator.

Therefore, there is an urgent need for research and development on porous membranes for the membrane contactor process that have excellent separation membrane performance such as permeation flux and salt rejection rate, and at the same time have excellent long-term stability by maintaining a dry state for a long time.

Fabrication and characterization of polyvinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) electrospun membranes for direct contact membrane distillation, Lalia BS et al., Journal of Membrane Science, 428, pp. 104-115 (2013)

The purpose of the present invention is to provide a porous separation membrane for a membrane contactor process with excellent long-term stability and a method for manufacturing the same.

In addition, the purpose of the present invention is to provide a porous separation membrane for a membrane contactor process with high permeation flux and salt rejection rate, and at the same time excellent long-term stability, and a method for manufacturing the same.

Specifically, the purpose of the present invention is to provide a porous separator for a membrane contactor process in which fluorine-based polymer fibers are accumulated three-dimensionally and have multiple pores, and a method for manufacturing the same.

The purpose of the present invention is to provide a method of manufacturing a porous separation membrane for a membrane contactor process with excellent contact angle and liquid permeation pressure by controlling the fiber diameter and pore size in a relatively simple process.

In order to achieve the above object, the present inventors conducted continuous research to develop a porous separation membrane for the membrane contactor process with excellent long-term stability, and developed a polymer fiber containing a copolymer with a specific fluorine-based repeating unit in a specific ratio. In the case of a porous separator for a membrane contactor process, the hydrophobicity is greatly improved, the permeation flux and salt rejection rate, which are membrane performances, are excellent, and the surprising fact that the membrane performance is maintained for more than 15 hours was completed to complete the present invention.

The present invention is a porous separator for a membrane contactor process in which polymer fibers are accumulated three-dimensionally and has a plurality of pores, wherein the polymer fibers include a copolymer represented by the following formula (1). provides.

[Formula 1]

(In Formula 1 above,

R ₁ and R ₂ are independently halogen or C _1-7 haloalkyl group,

x and y are the mole percent of each repeating unit in the copolymer,

x and y independently represent a real number of 1 or more,

y is 5 to 12 mol% based on the total repeating units in the copolymer.)

Preferably, the haloalkyl group of Formula 1 according to an embodiment of the present invention may be a perfluoroalkyl group.

More preferably, in Formula 1 according to an embodiment of the present invention, R ₁ may be fluoro (F), and R ₂ may be a perfluoromethyl group (-CF ₃ ).

In addition, y in Formula 1 according to an embodiment of the present invention may be 7 to 9 mol% based on the total repeating units in the copolymer.

The copolymer according to an embodiment of the present invention may have a weight average molecular weight (Mw) of 350,000 to 700,000 g/mol.

The copolymer according to an embodiment of the present invention may have a glass transition temperature (Tg) of -35 to -25°C.

The polymer fiber according to an embodiment of the present invention may have an average diameter of 0.5 to 0.8 ㎛.

The separator according to an embodiment of the present invention may be a structure having multiple pores by three-dimensionally accumulating polymer fibers manufactured by electrospinning the copolymer.

The separator according to an embodiment of the present invention may have a contact angle of 135° or more.

The separator according to an embodiment of the present invention may have a liquid entry pressure (LEP) of 150 kPa or more.

The separation membrane according to an embodiment of the present invention has the permeate flux and salt rejection rate measured under the conditions of a pressure of 46 Torr, a temperature of 70°C, and an aqueous sodium chloride solution with a concentration of 50 g/L flowing at a flow rate of 0.9 L/min. Equation 1 and Equation 2 can be satisfied simultaneously.

[Equation 1]

Jw _x /Jw _i ≥ 0.7

(In Equation 1 above,

Jw _x is the permeation flux (Flux) measured for 1 _minute after

[Equation 2]

R _x /R _i ≥ 0.9

(In Equation 2 above,

R _x is the salt rejection measured for 1 minute after x hours under the above conditions, and R _i is the salt rejection of the separation membrane measured for the initial 1 minute.

(In Equation 1 and Equation 2 above, x is a real number of 15 or more.)

The surface roughness of the separator according to an embodiment of the present invention may satisfy Equation 3 below.

[Equation 3]

_Ray /Ra ₀ ≥ 1.3

(In Equation 3 above,

Ra _y and Ra ₀ are the surface roughness of a porous separator for a membrane contactor process in which polymer fibers containing a copolymer in which y of Formula 1 is y mol% and 0 mol%, respectively, are accumulated three-dimensionally and have multiple pores. .)

A porous separation membrane for a membrane contactor process according to an embodiment of the present invention can be applied to a vacuum membrane distillation (VMD) process.

A separation membrane module including a porous separation membrane for a membrane contactor process according to an embodiment of the present invention can be provided.

The present invention includes the steps of (a) preparing a dope solution containing a copolymer represented by the following formula (1);

(b) manufacturing a separator having a plurality of pores by accumulating polymer fibers electrospun from the dope solution in three dimensions;

(c) a heat treatment step; a method for manufacturing a porous separation membrane for a membrane contactor process can be provided.

[Formula 1]

(In Formula 1 above,

R ₁ and R ₂ are independently halogen or C _1-7 haloalkyl group,

x and y are the mole percent of each repeating unit in the copolymer,

x and y independently represent an integer of 1 or more,

y is 5 to 12 mol% based on the total repeating units in the copolymer.)

Preferably, in the method for manufacturing a porous separation membrane for a membrane contactor process according to an embodiment of the present invention, R ₁ in Formula 1 may be fluoro (F), and R ₂ may be a perfluoromethyl group (-CF ₃ ).

Additionally, in the method for manufacturing a porous separator for a membrane contactor process according to an embodiment of the present invention, y in Formula 1 may be 7 to 9 mol% based on the total repeating units in the copolymer.

In the method for manufacturing a porous separator for a membrane contactor process according to an embodiment of the present invention, the dope solution may contain 20 to 30 wt% of the copolymer represented by Chemical Formula 1.

In the step (b) of manufacturing a porous separator for a membrane contactor process according to an embodiment of the present invention, polymer fibers obtained by electrospinning the dope solution are accumulated in three dimensions to produce a separator having a plurality of pores. The flow rate of the solution may be 0.05 to 1.0 ml/hr.

In the heat treatment step (c) of the method for manufacturing a porous separator for a membrane contactor process according to an embodiment of the present invention, the heat treatment temperature may be 80 to 120°C.

The present invention provides a porous separator for a membrane contactor process with excellent long-term stability by greatly improving the hydrophobicity of the separator using a copolymer containing fluorine-based repeating units in a specific ratio. Specifically, the porous separation membrane for the membrane contactor process has excellent separation membrane performance such as permeate flux and salt rejection rate, and has the advantage of excellent long-term stability as the above two performances are maintained for more than 15 hours.

When the porous separation membrane according to the present invention is applied to a membrane distillation process for seawater desalination, the effectiveness of the separation membrane is maintained for a long period of time, eliminating the need for unnecessary replacement, and improving the efficiency of the process more than before. In addition, the membrane can be applied not only to the membrane distillation process but also to membranes in various fields that require high hydrophobicity and membrane performance as described above.

Figure 1 is a schematic process diagram of a vacuum membrane distillation (VMD) process equipment for testing the performance of the porous membrane of the present invention.
Figure 2 is an image of the surface of the porous separator according to Example 1 and Comparative Examples 1 to 6 analyzed using a field emission scanning electron microscope (FE-SEM).
Figure 3 is an image of the cross-section of the porous membranes according to Example 1 and Comparative Examples 1 to 5 after the membrane distillation process analyzed by SEM-EDX (Scanning Electron Microscopy/Energy Dispersive X-ray Analysis).
Figure 4 is a graph showing the contact angle and LEP (liquid permeation pressure) results of the porous separators of Example 1 and Comparative Examples 1 to 6.
Figure 5 is an image of the surface of the porous separator of Example 1 and Comparative Examples 1 to 5 analyzed by scanning probe microscopy (AFM, Atomic Force Microscopy).
Figure 6 is a graph showing the surface roughness (Ra) measured by analyzing the surface of the porous membrane of Example 1 and Comparative Examples 1 to 5 using a scanning probe microscope (AFM).
Figure 7 is a graph showing the permeation flux results measured by applying the porous membranes of Example 1 and Comparative Examples 1 to 5 to a vacuum membrane distillation (VMD) process.
Figure 8 is a graph showing salt rejection results measured by applying the porous membranes of Example 1 and Comparative Examples 1 to 5 to a vacuum membrane distillation (VMD) process.
Figure 9 is a graph showing the results of measuring the pore size, LEP, and contact angle of the porous separators of Examples 1 to 3, Comparative Examples 1 to 3, and Comparative Examples 7 to 12.

Hereinafter, the present invention will be described in more detail. However, the following specific examples or examples are only a reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Additionally, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. The terminology used in the description herein is merely to effectively describe specific embodiments and is not intended to limit the invention.

Additionally, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to also include the plural forms, unless the context clearly dictates otherwise.

In addition, units used without special mention in this specification are based on weight, and as an example, the unit of % or ratio means weight % or weight ratio, and weight % refers to the amount of any one component of the entire composition unless otherwise defined. It refers to the weight percent occupied in the composition.

In addition, the numerical range used in this specification includes the lower limit and upper limit and all values within the range, increments logically derived from the shape and width of the defined range, all double-defined values, and the upper limit of the numerical range defined in different forms. and all possible combinations of the lower bounds. Unless otherwise specified in the specification of the present invention, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

As used herein, “comprises” is an open description with the same meaning as expressions such as “comprises,” “contains,” “has,” or “features,” and includes elements and materials that are not additionally listed. or does not exclude the process.

As used herein, “polymer” refers to a polymer or copolymer prepared by polymerizing monomers.

“Polymer fiber” as used herein refers to a type of fiber manufactured by spinning polymer. As an example, the polymer fiber may refer to a polymer fiber manufactured by spinning a dope solution in which a polymer is dissolved through a nozzle.

“Accumulation” as used herein means that continuously spun polymer fibers form a three-dimensional structure, and the spun polymer fibers can be three-dimensionally accumulated to form a porous separator.

“Surface roughness” as used herein may be used in the same sense as surface roughness.

As used herein, “alkyl” refers to a monovalent hydrocarbon radical and includes both straight-chain and branched forms.

As used herein, “halogen” and “halo” mean fluorine, chlorine, bromine or iodine.

As used herein, “haloalkyl” refers to an alkyl group in which one or more hydrogen atoms are each replaced by a halogen atom. For example, haloalkyl is -CF ₃ , -CHF ₂ , -CH ₂ F, -CBr ₃ , -CHBr ₂ , -CH ₂ Br, -CC1 ₃ , -CHC1 ₂ , -CH ₂ CI, -CI ₃ , -CHI ₂ , -CH ₂ I, -CH ₂ -CF ₃ , -CH ₂ -CHF ₂ , -CH 2 -CH ₂ F, -CH ₂ -CBr ₃ , -CH ₂ -CHBr ₂ , -CH _{2 -CH 2} Br, -CH ₂ -CC1 ₃ , -CH ₂ -CHC1 ₂ , -CH ₂ -CH ₂ CI, -CH ₂ -CI ₃ , -CH ₂ -CHI ₂ , -CH ₂ -CH ₂ I, and similar It includes Here alkyl and halogen are as previously defined.

As used herein, “perfluoroalkyl” means alkyl in which all C-H bonds are replaced with C-F.

“HFP (A%)” as used in the present invention refers to a copolymer of the following formula (1) where y is A mol%. For example, a copolymer in Formula 1 where y is 7.7 mol% can be expressed as HFP (7.7%).

Hereinafter, the present invention will be described in detail.

Previously, hydrophobic polymers such as PTFE, PP, PVDF, and PVDF-HFP were used as separation membranes in the process for seawater desalination, but when applied to the membrane distillation process, they become wet after a certain period of time and no longer perform as membranes. occurs. In order to solve this problem, the present invention was completed by polymerizing a fluorine-based copolymer having a specific fluorine-based repeating unit at a specific ratio and using it to manufacture a porous separator for the membrane contactor process with excellent long-term stability.

The present invention provides a porous separator for a membrane contactor process in which polymer fibers are accumulated three-dimensionally and has multiple pores. Preferably, the polymer fiber may include a copolymer represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ and R ₂ are independently halogen or C _1-7 haloalkyl groups, x and y are mole percent of each repeating unit in the copolymer, and x and y are independently 1 or more real numbers. It may be x+y=100, and y is 5 to 12 mol% based on the total repeating units in the copolymer.

Preferably, the haloalkyl group of Formula 1 according to an embodiment of the present invention may be a perfluoroalkyl group, and more preferably, R ₁ is fluoro (F), and R ₂ is a perfluoromethyl group (-CF ₃ ). It can be. Specifically, Chemical Formula 1 may be expressed as Chemical Formula 2 below.

[Formula 2]

In Formula 2, x and y are mol% of each repeating unit in the copolymer, and x+y=100, and y is 6 to 10 mol%, more specifically, relative to the total repeating units in the copolymer. It is 7 to 9 mol%.

In addition, y in Formula 1 according to an embodiment of the present invention may be 5 to 12 mol%, preferably 6 to 10 mol%, and more preferably 7 to 9 mol% based on the total repeating units in the copolymer. When the above range is satisfied, a copolymer with excellent hydrophobicity can be manufactured, and when a porous separator is manufactured using the copolymer, it can exhibit excellent contact angle and liquid permeation pressure (LEP). In addition, when the porous separation membrane is applied to a membrane distillation process, it is very good because it can secure long-term stability by maintaining excellent permeation flux and salt rejection rate for a long time.

The copolymer can be used without limitation as long as it is a polymerization method commonly used in the art or a known polymerization method. Specifically, it may be selected from bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization, and preferably, polymerization may be performed through emulsion polymerization to obtain a high-purity copolymer. More specifically, it may be emulsion polymerization including deionized water, an emulsifier, a monomer, and a water-soluble initiator. First, the emulsifier is sufficiently dissolved in deionized water, then the monomer and the initiator are added and reacted at 60 to 90° C., then cooled to obtain a copolymer dispersion, which is then subjected to precipitation and drying to obtain the final copolymer. The content of the emulsifier and initiator can be used without major limitations within the commonly used range, and additives such as molecular weight regulators and buffers can be further added for polymerization.

The copolymer according to an embodiment of the present invention may have a weight average molecular weight (Mw) of 10,000 to 900,000 g/mol, specifically 100,000 to 800,000 g/mol, and more specifically 350,000 to 700,000 g/mol. In addition, the number average molecular weight (Mn) may be 10,000 to 700,000 g/mol, specifically 120,000 to 300,000 g/mol, and the polydispersity index (PDI) may be 1 to 5, preferably 1 to 3, but is limited thereto. It doesn't work. The molecular weight and polydispersity index can be adjusted depending on the polymerization conditions. In the case of a copolymer that satisfies the above range, it is good because it can express the glass transition temperature, melting point, and mechanical properties targeted by the present invention.

The copolymer according to an embodiment of the present invention may have a glass transition temperature (Tg) of -40 to -15°C, preferably -35 to -20°C, more preferably -35 to -25°C, and has the formula (1) The glass transition temperature can be adjusted depending on the y value. Additionally, the copolymer according to an embodiment of the present invention may have a melting point (Tm) of 130 to 145°C, preferably 135 to 140°C. When producing polymer fibers by spinning a copolymer having a glass transition temperature and melting point in the above range, it is possible to manufacture a porous separator having the fiber diameter, pore size, and separator thickness targeted by the present invention.

The polymer fiber according to an embodiment of the present invention may have an average diameter of 0.1 to 1.5 ㎛. Preferably it may be 0.3 to 1.0 ㎛, more preferably 0.5 to 0.8 ㎛. In the case of a porous separator in which polymer fibers satisfying the above range are accumulated, it has the pore size targeted in the present invention and can exhibit excellent contact angle and liquid permeation pressure, and the performance of the separator can be further improved.

The separator according to an embodiment of the present invention may be a structure having multiple pores by three-dimensionally accumulating polymer fibers manufactured by electrospinning the copolymer. The specific conditions and method of electrospinning are the same as those described in the manufacturing method below, and the pore size and thickness of the separator can be adjusted depending on the conditions. Specifically, polymer fibers are manufactured by electrospinning a dope solution in which the copolymer is dissolved, and the polymer fibers are continuously and three-dimensionally accumulated to produce a structure with multiple pores, that is, a porous separator.

The separator according to an embodiment of the present invention may have an average pore size of 0.1 to 10 μm. It may preferably be 0.2 to 1.0 ㎛, more preferably 0.4 to 0.6 ㎛, but is not limited thereto. The pore size of the separator can be adjusted depending on fiber diameter, spinning conditions, presence or absence of post-treatment, etc., and in order to achieve the separator performance targeted by the present invention, it is preferable to have a pore size within the above range.

Additionally, as the y value of Formula 1 increases, the average diameter of the fiber may also increase. Since this also affects the size and distribution of the separator pores, it is desirable to set the y value to an appropriate range in order to manufacture the porous separator targeted by the present invention.

The separator according to an embodiment of the present invention may have a thickness of 1 to 150 μm. It may preferably be 10 to 100 ㎛, more preferably 60 to 80 ㎛, but is not limited thereto. The thickness of the separator can be adjusted depending on spinning conditions, presence or absence of post-treatment, etc., and in order to achieve the separator performance targeted by the present invention, it is preferable to have a thickness within the above range. Specifically, if the thickness is too thin, the permeation flux may be excellent, but the salt rejection rate may be low, and if the thickness is too thick, the salt rejection rate may be excellent, but the permeation flux may be low, so the porous membrane suitable for the conditions of the membrane contactor process may be used. It is desirable to use it by setting the thickness.

The separator according to an embodiment of the present invention may have a contact angle of 125° or more, preferably 135° or more, and more preferably 145° or more, and the upper limit is not particularly limited. The contact angle may be a contact angle for water. Additionally, the contact angle can be adjusted depending on the surface energy, degree of hydrophobicity, pore size, and surface roughness of the separator surface. Preferably, the surface energy and hydrophobicity of the separator surface can be adjusted through the y value of Formula 1, and the surface roughness and pore size can be adjusted according to spinning conditions and the presence or absence of post-treatment. In the case of a porous separator manufactured by spinning the copolymer represented by Formula 1 according to an embodiment of the present invention, the contact angle may be improved by more than 10% compared to a porous separator made of a polymer with y of 0 mol%. Preferably, when a porous separation membrane with a contact angle in the above range is applied to the membrane contactor process, it exhibits significantly improved permeation flux and salt rejection rate, and the two membrane performances are maintained for a long time, which is even better, ensuring long-term stability of the separation membrane. .

The separator according to an embodiment of the present invention may have a liquid entry pressure (LEP) of 150 kPa or more, preferably 200 kPa or more, more preferably 250 kPa or more, and the surface energy, degree of hydrophobicity, and pores of the surface of the separator. It can be adjusted depending on the size and surface roughness, etc. In the case of a porous separator manufactured by spinning the copolymer, the contact angle can be improved by 3 times, preferably 4 times, and even more preferably 5 times or more compared to a porous separator made of a polymer with y of 0 mol%. Preferably, when a porous membrane with a liquid permeation pressure in the above range is applied to the membrane contactor process, it exhibits significantly improved permeation flux and salt rejection rate, and the above two membrane performances are maintained for a long time, ensuring long-term stability of the membrane. Even better.

The porous separator according to an embodiment of the present invention has excellent contact angle and liquid penetration pressure, which is very desirable because the separator performance is improved. Conventionally, a hydrophobic separator was used in which the liquid permeation pressure increased and the contact angle decreased through a post-treatment process, but as a result, the separator performance was insufficient. On the other hand, the porous membrane of the present invention simultaneously improves the liquid permeation pressure and contact angle, making it possible to manufacture a porous membrane for the membrane contactor process with greatly improved performance. In addition, the separator has long-term stability and can exhibit excellent separator performance for a long time, which is good because it can further improve the efficiency of the membrane contactor process.

The porous separation membrane for the membrane contactor process of the present invention may be preferably used for the membrane distillation process. In general, membrane distillation processes include direct contact membrane distillation (DCMD), air gap membrane distillation (AGMD), sweeping gas membrane distillation (SGMD), and vacuum distillation. Vacuum membrane distillation (VMD), etc. Preferably, the porous membrane is applied to direct contact membrane distillation (DCMD) or vacuum membrane distillation (VMD), more preferably to vacuum membrane distillation (VMD) process. However, there is no particular limitation as long as the process can achieve the long-term stability targeted by the present invention.

The separation membrane according to an embodiment of the present invention can be applied to a membrane contactor process, specifically a membrane distillation process, to evaluate the membrane performance, and the membrane performance may include permeate flux and salt rejection rate. If both of the above two separator performances are maintained at a high level for a long period of time, the long-term stability can be evaluated as excellent. The porous separation membrane according to an embodiment of the present invention has significantly excellent long-term stability, which is very good because it can improve the efficiency of the membrane contactor process.

The separation membrane according to an embodiment of the present invention can be applied to a membrane distillation process test (permeation flux and salt rejection rate), and the specific conditions are a pressure of 46 Torr, a temperature of 70°C, and an aqueous sodium chloride solution with a concentration of 50 g/L. This may be a condition of flowing at a flow rate of 0.9 L/min, and the measured permeate flow rate and salt rejection rate may simultaneously satisfy Equations 1 and 2 below.

[Equation 1] Jw _x /Jw _i ≥ 0.7

In Equation 1, Jw _x is the flux _measured for 1 minute after The permeation flux refers to how much liquid permeates a unit area during unit time, and can be expressed as Flux or Water Flux, and can be calculated by dividing the measured permeation amount by the effective area and time of the separation membrane. Specifically, satisfying Equation 1 above may mean that the permeation flow rate after x hours is maintained at 70% or more with respect to the initial permeation flow rate. Equation 1 above may satisfy 0.7, preferably 0.75, and more preferably 0.8 or more.

[Equation 2] R _x /R _i ≥ 0.9

In Equation ₂ , _R The salt rejection rate refers to the removal rate of salt contained in the solution after permeation, and specifically satisfying Equation 2 may mean that the salt rejection rate after x hours is maintained at 90% or more with respect to the initial salt rejection rate. there is. Equation 2 above may satisfy 0.9, preferably 0.95, and more preferably 0.99 or more.

The method for calculating the salt rejection rate can be used without limitation as long as it is a known method commonly used in the art. Specifically, the conductivity of the aqueous solution before and after permeation through the separator is measured, the salt concentration is calculated by comparing it with the calibration value, and the rejection rate can be calculated using the following formula.

[Calculation Formula 2]

In addition, in the separator according to an embodiment of the present invention, in Equations 1 and 2, x may be a real number of 15 or more, specifically, a real number of 20 or more, or a real number of 30 or more, and more specifically, a real number of 35 or more. The permeate flux and salt rejection rate measured by applying the separation membrane according to the present invention simultaneously satisfy Equations 1 and 2 above, thereby maintaining a stable permeate flux and salt rejection rate despite long-term operation, thereby demonstrating further improved long-term stability. You can. On the other hand, if y does not satisfy 5 mol% to 12 mol%, the permeation flux and salt rejection rate decrease rapidly within 15 hours, which is not desirable because the function of the separation membrane is lost.

Additionally, the surface roughness of the separator according to an embodiment of the present invention may satisfy Equation 3 below. The surface and surface roughness of the separator can be analyzed using a scanning probe microscope (AFM, Atomic Force Microscope). Specifically, the surface roughness may refer to the center line average roughness (Ra).

[Equation 3] Ra _y /Ra ₀ ≥ 1.3

In Equation 3, Ra _y and Ra ₀ are porosity for the membrane contactor process in which polymer fibers containing a copolymer in which y in Formula 1 is y mol% and 0 mol%, respectively, are accumulated three-dimensionally and have a plurality of pores. This is the surface roughness of the separator. In Equation 3, y is the same as the description for y in Chemical Formula 1, and when y satisfies the above range, the surface roughness can satisfy Equation 3. Preferably, Equation 3 may be 1.6 or more, more preferably 1.8 or more, and a separator that satisfies the above range has excellent surface energy, contact angle, and liquid permeation pressure, so that further improved separator performance can be achieved.

A separation membrane module including a porous separation membrane for a membrane contactor process according to an embodiment of the present invention can be provided. In the case of the separator module, superior separator performance can be achieved in the process, and in particular, excellent performance can be maintained for a long time. In addition, the separation membrane module is better because it can improve the efficiency of the membrane contactor process by eliminating or shortening unnecessary replacement processes.

By spinning the copolymer according to an embodiment of the present invention, a porous separator for a membrane contactor process, which is a structure having multiple pores in which polymer fibers are accumulated in three dimensions, can be manufactured. Specifically, the spinning method can be performed using a general spinning device used in fiber manufacturing, such as electro spinning, solution spinning, melt-blown spinning, and solution blowing. blowing), etc. Preferably, the porous separator for the membrane contactor process can be manufactured from the copolymer by electrospinning or solution spinning, more preferably electrospinning. The principle and device configuration of the electrospinning are not particularly limited as long as they are commonly used or known in the art.

A method for manufacturing a porous separator for a membrane contactor process according to an embodiment of the present invention includes the steps of (a) preparing a dope solution containing a copolymer represented by the following formula (1); (b) manufacturing a separator having a plurality of pores by accumulating polymer fibers electrospun from the dope solution in three dimensions; (c) heat treatment step; may be included.

[Formula 1]

R ₁ , R ₂ , x and y in Formula 1 are the same as previously described in Formula 1.

In the step (a) of preparing a dope solution containing the copolymer represented by Formula 1 in the method for producing a porous separator for a membrane contactor process according to an embodiment of the present invention, the dope solution contains an organic solvent. Includes. The organic solvent is not particularly limited as long as it is a solvent that can dissolve the copolymer, and may be a polar or neutral organic solvent. For example, dimethylformamide (DMF), dimethyl sulfoxide (DMSO) dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), C _1-6 alcohols, tetrahydrofuran (THF) ), acetone, methyl ethyl ketone (MEK), etc., but is not limited thereto.

Preferably, the dope solution may contain 10 to 40 wt%, more preferably 20 to 30 wt%, of the copolymer represented by Formula 1, and the diameter and pores of the fiber produced depending on the concentration of the dope solution. The size can be adjusted. Additionally, the dope solution can be stirred at 20 to 80° C. for more than 12 hours, and a more uniformly dispersed dope solution can be prepared through this process.

In the step (b) of manufacturing a porous separator for a membrane contactor process according to an embodiment of the present invention, polymer fibers obtained by electrospinning the dope solution are accumulated in three dimensions to produce a separator having a plurality of pores. The flow rate of the solution may be 0.05 to 1.0 ml/hr, preferably 0.05 to 0.5 ml/hr, and more preferably 0.05 to 0.3 ml/hr. When the above range is satisfied, the pore size of the porous membrane is reduced, making it possible to manufacture a porous membrane for the membrane contactor process with excellent contact angle and liquid permeation pressure.

The specific process conditions of the electrospinning may be adjusted depending on the target physical properties of the separator to be manufactured, but is preferably 0 to 60 kV, specifically 10 to 60 kV, at a temperature of 10 to 50 ° C. and a relative humidity of 25 to 50%. The voltage is 30 kV, the distance between the nozzle and the collector is 5 to 20 cm, and the discharge rate is 0.001 ml/hr to 50 ml/hr, specifically 0.01 ml/hr to 10 ml/hr, more specifically 0.05 to 1.0 ml/hr. It can proceed under the following conditions. Additionally, the diameter of the nozzle may be 20 to 35 gauge, but is not greatly limited as long as it does not impair the physical properties targeted by the present invention.

After the electrospinning step, a process such as oven drying or hot air drying may be performed at a temperature of 60°C or lower to volatilize the remaining organic solvent, preferably at a temperature of 40°C or lower, more preferably at a temperature of 30°C or lower and 5°C or higher. It can be carried out in , and it may be carried out in a vacuum. At this time, drying conditions can be adjusted depending on the type of organic solvent and copolymer.

Heat treatment may be performed as the final step in the method of manufacturing a porous separator for a membrane contactor process according to an embodiment of the present invention. The heat treatment temperature may be 80 to 120°C, preferably 90 to 110°C, and more preferably 95 to 105°C. Additionally, the heat treatment time may be 1 to 24 hours, preferably 3 to 12 hours, and more preferably 5 to 10 hours. When the heat treatment process is performed under temperature and time conditions that satisfy the above range, the three-dimensionally accumulated polymer fibers can be fused together to form more dense membrane pores, which has improved contact angle and liquid penetration pressure. A porous separation membrane can be manufactured. The porous membrane is very good because it can maintain the membrane performance of excellent salt rejection rate and permeate flux for a long time, thereby ensuring long-term stability.

Hereinafter, the porous separator for the membrane contactor process according to the present invention will be described in more detail through examples and comparative examples. However, the following examples are only a reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms. Additionally, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. Additionally, the terms used in the description in the present invention are only intended to effectively describe specific embodiments and are not intended to limit the present invention.

[Physical property evaluation method]

1) Average molecular weight [g/mol] and distribution

The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (PDI) of the copolymers prepared in Preparation Examples and Comparative Preparation Examples were measured using GPC (YL9100, YL Instrument Co.). A pump (YL 9112), a refractive index detector (YL9170), a 30 cm PS gel-packed column, and a polystyrene standard were used, and DMF with 0.01 M LiBr dissolved as a standard solution was used at a flow rate of 0.8 ml/min at a temperature of 50°C. It was measured while flowing. The analysis sample was prepared by diluting the copolymer to a concentration of 1 mg/ml or less and then diluting the copolymer to a concentration of 0.1 mg/ml or less. Analysis was performed by adding ml.

2) Glass transition temperature (Tg) [℃]

The glass transition temperature of the copolymers prepared in Preparation Examples and Comparative Preparation Examples was measured using a differential scanning calorimeter (Q1000, TA Instruments). Analysis was conducted in a temperature range of -80 to 25°C at a temperature increase rate of 10°C/min.

3) Thermal decomposition temperature (Td) [℃]

The thermal decomposition temperature of the copolymers prepared in Preparation Examples and Comparative Preparation Examples was measured using a thermogravimetric analyzer (Q5000, TA Instruments). Thermal decomposition temperature was analyzed by heating from room temperature to 600°C at a temperature increase rate of 10°C/min.

4) Liquid entry pressure (LEP) [kPa]

The liquid entry pressure (LEP) of the porous membranes prepared in Examples and Comparative Examples was measured using a capillary flow porometer (PMI) system. Analysis was performed by placing the porous membrane in a chamber connected to a pressurizing device, filling the chamber with deionized water (DI water), and then slowly pressurizing it. While maintaining room temperature, the temperature was gradually increased by 50 kPa at 10-minute intervals, and the pressure when water droplets were observed on the other side of the separator was measured as liquid inlet pressure (LEP).

5) Contact angle and surface energy

The contact angle of the porous membranes prepared in Examples and Comparative Examples with respect to water was measured using a drop shape analyzer (KRUSS GmbH 22453 Hamburg).

Additionally, the surface energy of the porous separator was calculated using the Owens-Wendt-Rabel-Laelble method.

6) Thicknesses

The thickness of the porous separator prepared in Examples and Comparative Examples was measured 5 times using a digital micrometer, and the average value was recorded.

7) Mechanical strength

Samples were prepared by cutting the porous separators prepared in Examples and Comparative Examples to a size of 5 mm x 20 mm, and the tensile strength, Young's modulus, and elongation at break of the samples were measured.

8) Average fiber diameter of polymer fiber and pore size of porous membrane

The porous separators prepared in Examples and Comparative Examples were analyzed using field-emission scanning electron microscopy (FE-SEM), and the diameters of the fibers visible in the images were measured 10 times and the average value was recorded.

In addition, after immersing the porous membrane in Galwick solution for more than 10 minutes, the pore size and distribution of the porous membrane were analyzed using a capillary flow porometer (PMI) system.

9) Surface Roughness

The surface of the porous separator prepared in Examples and Comparative Examples was observed using a scanning probe microscope (AFM, Atomic Force Microscope) and the surface roughness was analyzed. The surface roughness value was recorded as the center line average roughness (Ra).

10) Separator performance

The performance of the porous membranes prepared in Examples and Comparative Examples was evaluated using Vacuum Membrane Distillation (VMD) process equipment. A porous separation membrane with an effective area of 15.2 cm2 was installed in the facility, and an aqueous sodium chloride solution with a temperature of 70°C, a concentration of 50 g/L, and a conductivity of 70 mS/cm was circulated at a flow rate of 0.90/min with a pump, and the vacuum pressure While maintaining the temperature at 46 Torr, the conductivity of the supplied aqueous solution and permeated fresh water was monitored using a conductivity meter (CON 11 Economy Meter). To aid understanding, a rough process diagram of the VMD process is shown in Figure 1.

The membrane performance was measured by measuring flux and salt rejection, and the calculation formula was as follows.

[Calculation Formula 1]

In the above calculation equation 1, Jw is the permeation flow rate (L/㎡h), V is the amount of fresh water permeated (L), A is the effective area of the separation membrane (㎡), and t is the permeation time (h). The permeation flux results of Examples and Comparative Examples calculated using Equation 1 above were normalized and expressed as values of 0 to 1 (Normalized Flux), which were graphed and shown in FIG. 7.

[Calculation Formula 2]

In the above calculation formula 2, R is the salt rejection rate (%), Cf is the salt concentration of the supplied aqueous solution (mg/L), Cp is the salt concentration of the permeated fresh water (mg/L), and the salt concentration is calculated using the measured conductivity. It can be calculated by:

Long-term stability was recorded as the maximum time x (hr) for which the permeate flux and salt rejection rate of the separation membrane simultaneously satisfy Equations 1 and 2 below. The salt rejection ratio results of Examples and Comparative Examples calculated using Equation 2 above were graphed and shown in FIG. 8.

In addition, in Equations 1 and 2 below, when x is a real number of 15 or more and Equations 1 and 2 below are simultaneously satisfied, the long-term stability of the separator was evaluated to be excellent.

[Equation 1] Jw _x /Jw _i ≥ 0.7

In equation 1 above,

Jw _x is the flux measured for 1 minute after x hours under the above conditions, and Jw _i is the flux flux of the separation membrane measured for the initial 1 minute.

[Equation 2] R _x /R _i ≥ 0.9

In equation 2 above,

R _x is the salt rejection measured for 1 _minute after

[Preparation Examples 1 to 3 and Comparative Preparation Examples 1 to 3] Polymerization of PVDF-co-HFP copolymer

280 g of deionized water and 0.7 g of emulsifier APFO (Ammonium perfluorooctanoate, TCI) were added to a 1L stainless steel reactor and thoroughly stirred at 82°C. Next, the monomers VDF (1,1-Difluoroethylene, Apollo) and HFP (Hexafluoropropylene, Career Henan Chemical) were added in the weight range shown in Table 1 below, and the initiator SPS (sodium persulfate, Na ₂ S ₂ O ₈ , Sigma-Aldrich) was added. 0.279 g was added with an aqueous solution completely dissolved in 20 g of deionized water, and then reacted until the reactor pressure no longer decreased. After the reaction was completed, it was cooled below 40°C to obtain a PVDF-co-HFP copolymer dispersion. An aqueous NaCl (saturated sodium chloride) solution was added to the dispersion to precipitate only the copolymer, which was washed several times with deionized water and dried in a vacuum oven at 50°C for more than 24 hours to produce the target product PVDF-co- represented by the following formula (2): HFP copolymer was obtained.

[Formula 2]

(In Formula 2 above,

x and y are the mole percent of each repeating unit in the copolymer,

The sum of x and y is 100 mol%.)

The weight average molecular weight (Mw), glass transition temperature (Tg), and thermal decomposition temperature (Tm) of the obtained copolymer were measured and shown in Table 1 below. In the PVDF-co-HFP copolymer represented by Formula 2, y The mole percent was analyzed using a ¹⁹ F NMR spectrometer (AVANCE 700 MHz, Bruker), and the results are shown in Table 1 below.

Input monomer weight (g) y (mol%) in Formula 2 Mw
(g/mol) Tg (℃) Tm (℃) HFP VDF Manufacturing Example 1
HFP (7.4%) 5.7g 35.1g 7.4 423,000 -29.0 141 Preparation Example 2HFP (7.7%) 6.7g 35.6 g 7.7 410,000 -28.0 138 Preparation Example 3HFP (8.4%) 7.6 g 35.2 g 8.4 399,000 -26.8 135 HFP(0%) ^Solef® 1015 (Solvay) 0 - -41.5 174 HFP (2.3%) Kynar Flex ^® LBG (ARKEMA, HFP 2 mol%) 2.3 883,000 -40.0 153 HFP (4.5%) Kynar Flex ^® 2800 (ARKEMA, HFP 5 mol%) 4.5 670,000 -35.0 146 Comparative Manufacturing Example 1
HFP (12.7%) 20.6 g 49.8g 12.7 441,000 -20.9 128 Comparative Manufacturing Example 2HFP (20.1%) 22.4g 38.9g 20.1 459,000 -15.9 112 Comparative Manufacturing Example 3HFP (32.2%) 21.6g 13.9g 32.2 229,000 -8.5 107

[Example 1 and Comparative Examples 1 to 6] Preparation of porous separator using electrospinning

HFP (0%) to HFP (32.2%) of Table 1 and the organic solvent DMF were added according to Table 2 below and stirred at 60°C for 24 hours to prepare a uniformly dispersed dope solution. 3 ml of the dope solution was injected into a NORM-JECT syringe connected to a 27 gauge stainless steel needle, and electrospun with an electrospinning device (ESR200R2D, NanoNC, Korea) at a temperature of 25°C and a relative humidity of 30 to 35% to form a porous separator. was manufactured. Specifically, the electrospinning was carried out under the conditions that the voltage was 15 kV, the distance between the nozzle and the collector was 12 cm, the discharge rate of the dope solution was 0.1 ml/hr, and the winding speed of the drum collector was 400 RPM. The prepared porous membrane was then dried with hot air in an oven at 20°C to remove the remaining solvent, and then heat-treated in an oven at 100°C for 60 minutes to prepare a porous membrane. The physical properties of the prepared separator were evaluated and shown in Table 3 below, and the surface of the separator was analyzed by FE-SEM and shown in Figure 2. As shown in Figure 2 and Table 3, it was confirmed that the diameter of the fiber became thicker as the mole percent of HFP increased. In particular, in the case of Comparative Example 6 using HFP (32.2%), excessive fusion between fibers occurred during the heat treatment process. It was confirmed that the separator performance was significantly reduced.

In addition, the performance of the porous separators of Example 1 and Comparative Examples 1 to 5 was evaluated and shown in Table 4, and the cross-section of the separator after the membrane distillation process was analyzed using SEM-EDX (BRUKER, QUANTAZX 200) and shown in Figure 3. . As shown in Figure 3, in the case of Comparative Example 1, the membrane became wet as soon as the membrane distillation process test started, so further evaluation could not be performed, and in the case of Comparative Examples 2 and 3, the membrane could only last 7 and 12 hours. On the other hand, in Example 1, excellent separator performance was maintained for more than 35 hours, confirming the long-term stability targeted by the present invention.

The contact angle and LEP results among the physical properties of the porous separators of Example 1 and Comparative Examples 1 to 6 are shown in Figure 4, and it was confirmed in Figure 4 that the contact angle and LEP values of Example 1 were the best.

In addition, the results of analyzing the surface roughness of Example 1 and Comparative Examples 1 to 5 using AFM are shown in Figures 5 and 6, and it was confirmed that the surface roughness of Example 1 was the best. As shown in Tables 3 and 4 below, in the case of Example 1, which has excellent surface roughness, a more dense separator can be formed, resulting in greatly improved separator performance compared to the comparative example.

The permeation flux and salt rejection rate results of the porous membranes of Example 1 and Comparative Examples 1 to 5 were graphed and shown in Figures 7 to 8. As shown in Figures 7 to 8, only in Example 1 Equations 1 and 2 were simultaneously satisfied, and through this, it was confirmed that the long-term stability of the porous separation membrane for the membrane contactor process of the present invention was excellent.

Table 2 below shows the content of the composition of the dope solution in Example 1 and Comparative Examples 1 to 6, Table 3 below shows the results of measuring the physical properties of the porous separator, and Table 3 below shows the membrane performance of the porous separator. It's about.

copolymer used
(Polymer used) Copolymer content (wt%) DMF content (wt%) Example 1 HFP (7.7%) 28 72 Comparative Example 1 HFP (0%) 18 82 Comparative Example 2 HFP (2.3%) 20 80 Comparative Example 3 HFP (4.5%) 24 76 Comparative Example 4 HFP (12.7%) 20 80 Comparative Example 5 HFP (20.0%) 22 78 Comparative Example 6 HFP (32.2%) 35 65

polymer fiber diameter Pore size thickness contact angle LEP surface roughness Example 1 HFP (7.7%) 0.72 ㎛ 0.45 ㎛ 74㎛ 147.5° 280 kPa 380㎚ Comparative Example 1 HFP (0%) 0.27 ㎛ 0.49 ㎛ 65㎛ 129° 50 kPa 200 nm Comparative Example 2 HFP (2.3%) 0.47 ㎛ 0.46 ㎛ 68㎛ 145° 140 kPa 250 nm Comparative Example 3 HFP (4.5%) 0.57 ㎛ 0.45 ㎛ 69㎛ 145° 190 kPa 320 nm Comparative Example 4 HFP (12.7%) 0.84 ㎛ 0.46 ㎛ 63㎛ 142° 120 kPa 120 nm Comparative Example 5 HFP (20.0%) 1.2 ㎛ 0.47 ㎛ 57㎛ 135° 80 kPa 80㎚ Comparative Example 6 HFP (32.2%) 1.8 ㎛ 0.39 ㎛ 40㎛ 128° N/A N/A

polymer Permeation flow rate (L/㎡hr) Salt rejection rate (%) Long-term stability (hr) Example 1 HFP (7.7%) 32.6 99.99 over 35 Comparative Example 1 HFP (0%) 0 0 0 Comparative Example 2 HFP (2.3%) 0 0 7 Comparative Example 3 HFP (4.5%) 12.4 40.00 12 Comparative Example 4 HFP (12.7%) 0 0 3 Comparative Example 5 HFP (20.0%) 0 0 2 Comparative Example 6 HFP (32.2%) 0 0 0

[Example 2 to Comparative Examples 7 to 9]

The same procedure as Example 1 was carried out except that the discharge rate of the dope solution was 0.2 ml/hr, Solef ^® 1015 (HFP (0%)), Kynar Flex ^® LBG (HFP (2.3%) ), Kynar Flex ^® 2800 (HFP (4.5%)), and HFP (7.7%) of Preparation Example 1 were used to prepare porous separators according to Examples 2 to Comparative Examples 7 to 9. The physical properties of the manufactured separator were evaluated and are shown in Figure 9 below.

[Example 3 to Comparative Examples 10 to 12]

The same procedure as Example 1 was carried out except that the discharge rate of the dope solution was 0.5 ml/hr, Solef ^® 1015 (HFP (0%)), Kynar Flex ^® LBG (HFP (2.3%) ), Kynar Flex ^® 2800 (HFP (4.5%)) and HFP (7.7%) of Preparation Example 1 were used to prepare porous separators according to Examples 3 to Comparative Examples 10 to 12. The physical properties of the manufactured separator were evaluated and are shown in Figure 9 below.

Copolymer (polymer) Dope solution concentration (wt%) discharge speed Example 1 HFP (7.7%) 28% 0.1ml/hr Example 2 HFP (7.7%) 28% 0.2ml/hr Example 3 HFP (7.7%) 28% 0.5 ml/hr Comparative Example 1 HFP (0%) 18% 0.1ml/hr Comparative Example 2 HFP (2.3%) 20% 0.1ml/hr Comparative Example 3 HFP (4.5%) 24% 0.1ml/hr Comparative Example 7 HFP (0%) 20% 0.2ml/hr Comparative Example 8 HFP (2.3%) 23% 0.2ml/hr Comparative Example 9 HFP (4.5%) 28% 0.2ml/hr Comparative Example 10 HFP (0%) 20% 0.5 ml/hr Comparative Example 11 HFP (2.3%) 23% 0.5 ml/hr Comparative Example 12 HFP (4.5%) 28% 0.5 ml/hr

As shown in Figure 9, it was confirmed that Examples 1 to 3 had denser pore sizes, excellent contact angles, and LEP compared to Comparative Examples 1 to 3 and 7 to 12. In addition, it was confirmed that when the discharge rate of the dope solution was 0.1 ml/hr, it exhibited more excellent physical properties.

Through the above examples, the porous separator for the membrane contactor process of the present invention was manufactured by electrospinning a copolymer with excellent hydrophobicity, and the separator has physical properties such as advantageous pore size, fiber diameter, contact angle, and LEP, and has excellent separator performance. By showing that this can be maintained for a long period of time, it was confirmed that long-term stability is excellent. The separation membrane of the present invention can be applied to a membrane distillation process for seawater desalination to further improve efficiency, and can be applied to various fields that require a separation membrane with high hydrophobicity even if it is not necessarily a membrane distillation process.

As described above, the present invention has been described with specific details and limited embodiments, but these are provided only to facilitate a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the field to which the present invention belongs is not limited to the above embodiments. Those skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

Claims (20)

A porous separator for a membrane contactor process in which polymer fibers are accumulated three-dimensionally and has a plurality of pores, wherein the polymer fibers include a copolymer represented by the following formula (1).
[Formula 1]

In Formula 1,
R ₁ is fluoro (F),
R ₂ is a perfluoromethyl group (-CF ₃ ),
x and y are the mole percent of each repeating unit in the copolymer,
x and y independently represent a real number of 1 or more,
y is 5 to 12 mol% based on the total repeating units in the copolymer. delete delete According to clause 1,
A porous separator for a membrane contactor process in which y in Formula 1 is 7 to 9 mol% based on the total repeating units in the copolymer. According to clause 1,
The copolymer is a porous separator for a membrane contactor process having a weight average molecular weight (Mw) of 350,000 to 700,000 g/mol. According to clause 1,
The copolymer is a porous separator for a membrane contactor process with a glass transition temperature (Tg) of -35 to -25°C. According to clause 1,
The polymer fiber is a porous separator for the membrane contactor process with an average diameter of 0.5 to 0.8㎛. According to clause 1,
The separator is a porous separator for the membrane contactor process, which is a structure having multiple pores by accumulating three-dimensionally polymer fibers produced by electrospinning the copolymer. According to clause 1,
The separator is a porous separator for the membrane contactor process with a contact angle of 135° or more. According to clause 1,
The separator is a porous separator for the membrane contactor process with a liquid entry pressure (LEP) of 150 kPa or more. According to clause 1,
The permeate flow rate and salt rejection rate of the separation membrane measured under the conditions of a pressure of 46 Torr, a temperature of 70°C, and an aqueous solution of sodium chloride with a concentration of 50 g/L flowing at a flow rate of 0.9 L/min simultaneously satisfy Equations 1 and 2 below. A porous separation membrane for the membrane contactor process.
[Equation 1] Jw _x /Jw _i ≥ 0.7
In equation 1 above,
Jw _x is the flux measured for 1 minute after x hours under the above conditions, and Jw _i is the flux flux of the separation membrane measured for the initial 1 minute.
[Equation 2] R _x /R _i ≥ 0.9
In equation 2 above,
R _x is the salt rejection rate (rejection) _measured for 1 minute after
In Equations 1 and 2 above, x is a real number of 15 or more. According to clause 1,
The separator is a porous separator for a membrane contactor process whose surface roughness satisfies Equation 1 below.
[Equation 3] Ra _y /Ra ₀ ≥ 1.3
In equation 3 above,
Ra _y and Ra ₀ are the surface roughness of a porous separator for a membrane contactor process in which polymer fibers containing a copolymer in which y of Formula 1 is y mol% and 0 mol%, respectively, are accumulated three-dimensionally and have multiple pores. . According to clause 1,
The porous membrane for the membrane contactor process is a porous membrane for the membrane contactor process that is applied to the vacuum membrane distillation (VMD) process. A separation membrane module comprising a porous membrane for a membrane contactor process according to any one selected from claims 1 and 4 to 13. (a) preparing a dope solution containing a copolymer represented by the following formula (1);
(b) manufacturing a separator having a plurality of pores by accumulating polymer fibers electrospun from the dope solution in three dimensions; and
(c) heat treatment step;
A method of manufacturing a porous separation membrane for a membrane contactor process comprising a.
[Formula 1]

In Formula 1,
R ₁ is fluoro (F),
R ₂ is a perfluoromethyl group (-CF ₃ ),
x and y are the mole percent of each repeating unit in the copolymer,
x and y independently represent an integer of 1 or more,
y is 5 to 12 mol% based on the total repeating units in the copolymer. delete According to clause 15,
A method for producing a porous separation membrane for a membrane contactor process, wherein y in Formula 1 is 7 to 9 mol% based on the total repeating units in the copolymer. According to clause 15,
The dope solution is a method of producing a porous separator for a membrane contactor process, wherein the copolymer represented by Formula 1 is contained in an amount of 20 to 30 wt%. According to clause 15,
In the step (b) of manufacturing a separator having a plurality of pores by accumulating three-dimensionally the polymer fibers obtained by electrospinning the dope solution,
A method of manufacturing a porous separator for a membrane contactor process, wherein the flow rate of the dope solution is 0.05 to 1.0 ml/hr. According to clause 15,
In the heat treatment step (c), the heat treatment temperature is 80 to 120°C.