KR102634725B1 - Hollow fiber membrane surface-treated with perfluoropolyether based coating agent and method of manufacturing same - Google Patents

Abstract

A hollow fiber membrane surface-treated with a perfluorinated polyether-based coating agent and a method for manufacturing the same are disclosed. The surface-treated hollow fiber membrane is a hollow fiber membrane containing hollow fibers; and a surface modification layer formed on the surface of the hollow fiber, wherein the surface modification layer is formed through a condensation reaction of perfluoropolyether silane, and the perfluoropolyether silane includes a perfluoropolyether chain; and a trialkoxy silane group bonded to the end of the perfluorinated polyether chain and having an alkoxy carbon number of 1 to 6. The surface-treated hollow fiber membrane causes less wetting and has excellent durability.

Description

Hollow fiber membrane surface-treated with perfluorinated polyether-based coating and method for manufacturing the same

The present invention relates to a hollow fiber membrane surface-treated with a perfluorinated polyether-based coating agent and a method for manufacturing the same, and specifically includes a surface treatment layer formed using a perfluorinated polyether-based coating agent on the surface of the hollow fiber membrane containing hollow fibers. By doing so, it relates to a surface-treated hollow fiber membrane with low wetting phenomenon and high durability and a method of manufacturing the same.

Membrane contactor is a process that selectively separates one or more components by contacting an absorbent with a gas through a membrane. It is a hybrid technology that combines the advantages of liquid absorption (high selectivity) and membrane separation (modularity and miniaturization). Recently, the development of membrane contactor technology to reduce acidic gases such as CO ₂ , H ₂ S, and SO ₂ generated during natural gas, industrial processes, and combustion of fossil fuels has been attracting attention.

Membranes used in membrane contactors include flat, spiral wound, tubular, and hollow fiber types, but hollow fiber membranes have recently attracted the most attention because they can maximize the membrane area per unit volume compared to other formulations and enable compact module configuration. I'm receiving it.

Meanwhile, when the membrane is operated for a long time, chemical and thermal shock is applied to the membrane, which causes the absorbent liquid to penetrate into the membrane. When the membrane is in continuous contact with the absorbent, the porosity, pore shape, surface structure and properties of the membrane change due to chemical action.

In addition, when the pores of the membrane are wetted by the absorbent liquid during the membrane contactor process, the mass transfer resistance greatly increases and the performance of the membrane contactor deteriorates rapidly. In order to maintain the performance for a long time, the membrane's It is important to maintain the pores in a non-wetting state during operation.

Therefore, research is required on a membrane for a membrane contactor that can maintain a non-wetting state and has a high acid gas removal rate even during long-term operation, and on its manufacturing method.

The purpose of the present invention is to solve the above problems and to provide a hollow fiber membrane for a membrane contactor with low wetting phenomenon by absorbent liquid and high durability and a method for manufacturing the same.

In addition, the aim is to provide a membrane contactor with a high acid gas removal rate even when operated for a long time and an acid gas separation method using the same.

According to one aspect of the present invention, a hollow fiber membrane containing hollow fibers; and a surface modification layer formed on the surface of the hollow fiber, wherein the surface modification layer is formed through a condensation reaction of perfluoropolyether silane, and the perfluoropolyether silane includes a perfluoropolyether chain; and a trialkoxy silane group bonded to the end of the perfluorinated polyether chain and having an alkoxy carbon number of 1 to 6.

Additionally, the perfluorinated polyether silane may be a compound represented by structural formula 1 below.

[Structural Formula 1]

In structural formula 1,

R is each a hydrogen atom or a C1 to C6 alkyl group,

A is a perfluoropolyether chain.

In addition, the surface-modified hollow fiber membrane includes a surface-modified layer in which the perfluorinated polyether silane further condenses with hydrogen atoms (H) on the surface of the hollow fiber to form a covalent bond with the hollow fiber, and has the structural formula 2 below: It may have a structure of

[Structural Formula 2]

In structural formula 2,

m is the number of repetitions of the repeat unit,

A is a perfluoropolyether chain.

In addition, the surface-modified hollow fiber membrane includes a surface-modified layer in which the perfluorinated polyether silane further condenses with the hydroxyl group (-OH) on the surface of the hollow fiber to form a covalent bond with the hollow fiber, and has the structural formula 3 below: It may have a structure of

[Structural Formula 3]

In structural formula 3,

n is the number of repetitions of the repeat unit,

A is a perfluoropolyether chain.

Additionally, the hollow fiber may be a polymer hollow fiber.

In addition, the polymer hollow fiber may include at least one selected from the group consisting of polypropylene (PP) hollow fiber, hydroxylated polypropylene (hydroxylated PP) hollow fiber, and polyvinylidene fluoride (PVDF) hollow fiber.

According to another aspect of the present invention, the surface-treated hollow fiber membrane; and an absorbent. A membrane contactor for use in acid gas separation is provided.

In addition, the absorbent includes an amine compound and an additive, and the amine compound is monoethanolamine (MEA), 2-amino-2-hydroxymethyl-1,3-propanediol (2-amino-2-hydroxymethyl-1 ,3-propanediol, AHPD), 2-amino-2-methyl-1,3-propanediol (2-amino-2-methyl-1,3-propanediol, AMPD), 2-aminomethyl-2-hydroxymethyl -1,3-propanol (2-aminomethyl-2-hydroxymethyl-1,3-propanediol), 2-amino-1,1,1-ethanetriol (2-amino-1,1,1-ethanetriol), hydrazine (hydrazine), ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, diethanolamine, triethanolamine, and N-methyldiethanolamine, and the additive Glycine, sarcosine, piperazine, 2-(1-piperazinyl)-ethylamine (PZEA), aminomethyl propanol, It may include one or more selected from the group consisting of AMP), potassium carbonate (K2CO3), trisodium phosphate (TSP), and tetraethylenepentamine (TEPA).

Additionally, the acid gas may include one _or more types selected from the group consisting of carbon dioxide (CO ₂ ), nitrogen oxides _{( NO}

According to another aspect of the present invention, (a) preparing a coating solution containing perfluoropolyether silane; and (b) manufacturing a surface-modified hollow fiber membrane by coating the surface of the hollow fiber included in the hollow fiber membrane with the coating solution and forming a surface modification layer through a condensation reaction, wherein the perfluorinated polyether silane is perfluorinated polyether chain; and a trialkoxy silane group bonded to the end of the perfluorinated polyether chain and having an alkoxy carbon number of 1 to 6. A method for producing a surface-modified hollow fiber membrane comprising a trialkoxy silane group is provided.

Additionally, the perfluorinated polyether silane may be a compound represented by structural formula 1 below.

[Structural Formula 1]

In structural formula 1,

R is each a hydrogen atom or a C1 to C6 alkyl group,

A is a perfluoropolyether chain.

In addition, in step (b), as shown in Scheme 1 below, the perfluorinated polyether silane (1) further condenses with the hydrogen atoms (H) on the surface of the hollow fiber (2) to form a covalent bond with the hollow fiber (2). This may be a step of manufacturing a surface-modified hollow fiber membrane 3 having a formed surface modification layer.

[Scheme 1]

In Scheme 1 above,

R is each a hydrogen atom or a C1 to C6 alkyl group,

A is a perfluoropolyether chain,

m is the number of repetitions of the repeating unit.

In addition, in step (b), as shown in Scheme 2 below, the perfluorinated polyether silane (1') undergoes an additional condensation reaction with the hydroxyl group (-OH) on the surface of the hollow fiber (2') to form the hollow fiber (2'). This may be a step of manufacturing a surface-modified hollow fiber membrane (3') having a surface-modified layer forming a covalent bond.

[Scheme 2]

In Scheme 2 above,

R is each a hydrogen atom or a C1 to C6 alkyl group,

A is a perfluoropolyether chain,

n is the number of repetitions of the repeating unit.

In addition, in the method of manufacturing a surface-modified hollow fiber membrane for a membrane contactor, before step (b), (b') the hollow fiber membrane containing the hollow fiber is surface treated with a surface treatment agent containing an acid and an oxidizing agent, thereby treating the surface of the hollow fiber membrane. It may further include forming a hydroxy group (-OH).

In addition, the coating solution includes a fluorine-based solvent, and the fluorine-based solvent is ethoxy-nonafluoropentane (C ₄ F ₉ OC ₂ H ₅ ), methoxy-nonafluorobutane (methoxy-nonafluorobutane, C ₄ F ₉ OC ₁ H ₅ ), decafluoro methoxy trifluoro methyl pentane (1,1,1,2,3,4,4,5,5,5-Decafluoro-3-methoxy-2-(trifluoromethyl ) pentane), hexafluorobenzene, octadecafluorooctane, octafluorocyclopentene, and hexadecafluoroheptane. there is.

In addition, the method of manufacturing the surface-modified hollow fiber membrane includes, before step (b), (b") irradiating plasma to a hollow fiber membrane containing hollow fibers to make the surface of the hollow fiber membrane hydrophilic; may additionally be included.

According to another aspect of the present invention, (1) preparing the membrane contactor; and (2) supplying acid gas to the membrane contactor to separate the acid gas.

In addition, step (2) includes (2-1) contacting the acid gas with the absorbent to absorb the acid gas into the absorbent; and (2-2) removing the acid gas absorbed in the absorbent.

Additionally, step (2-1) may be performed at 0°C to 80°C, and step (2-2) may be performed at 80°C to 150°C.

The surface-treated hollow fiber membrane of the present invention has the effect of reducing wetting and increasing durability by modifying the surface of the hollow fiber using perfluoropolyether silane.

In addition, the membrane contactor of the present invention includes the surface-treated hollow fiber membrane, thereby achieving a high acid gas removal rate even when operated for a long time.

Since these drawings are for reference in explaining exemplary embodiments of the present invention, the technical idea of the present invention should not be interpreted as limited to the attached drawings.
Figure 1 is a schematic diagram showing a method for separating acid gas from a membrane for a membrane contactor according to an embodiment of the present invention.
Figure 2 shows an SEM image of the hollow fiber membrane manufactured according to Example 1 and Comparative Example 1.
Figure 3 shows the results of FT-IR analysis of the hollow fiber membrane prepared according to Example 1 and Comparative Example 1.
Figure 4 is a graph showing the average value of the water contact angle of the hollow fiber membranes manufactured according to Examples 1 to 4 and Comparative Examples 1 and 2.
Figure 5 is a schematic diagram of an analysis device for measuring the carbon dioxide absorption rate of a membrane contactor manufactured according to one embodiment of the present invention.
Figure 6 is a graph showing the carbon dioxide absorption rate and stability of the membrane contactor according to Device Example 1 and Device Comparative Example 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention.

However, the following description is not intended to limit the present invention to specific embodiments, and in describing the present invention, if it is determined that a detailed description of related known technology may obscure the gist of the present invention, the detailed description will be omitted. .

The terminology used herein is only used to describe specific embodiments and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, or a combination thereof described in the specification, but are not intended to indicate the presence of one or more other features or It should be understood that numbers, steps, operations, components, or combinations thereof do not preclude the existence or addition possibility.

Additionally, terms including ordinal numbers, such as first, second, etc., which will be used below, may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention.

Additionally, when a component is referred to as being "formed" or "laminated" on another component, it may be formed or laminated directly on the entire surface or one side of the surface of the other component, but may also mean that the component is "formed" or "laminated" on another component. It should be understood that other components may exist in

Before explaining the hollow fiber membrane surface-treated with the perfluorinated polyether coating agent according to the present invention and its manufacturing method, the sol-gel method will be described.

In general, the sol-gel method refers to a method of producing glass or ceramics at a relatively low temperature using hydrolysis and condensation reactions of metal alkoxide and M(OR)n.

Here, sol is a state in which solid particles are dispersed in a colloidal form in a liquid phase. In particular, the size of the solid particles is very small (several nm to hundreds of nm), meaning a state in which Brownian motion is possible with little influence of gravity. , Gel refers to a state in which the components of a sol form a network or polymer chain connected to each other by specific chemical and physical bonds and lose fluidity. The gel state includes cases where the solid phase forms a network and the liquid phase is fixed within the network.

The sol-gel method is a technology that can be controlled to achieve specific physical properties at all stages until the sol is gelled, and can be said to be a method of manufacturing materials through sol formation, gelation, and solvent removal. In the gel state, the formed network or polymer chain has the same refractive index as the surrounding sol, so it is observed in a transparent state. However, if the concentration of particles is much higher than that of the surrounding sol, the refractive index and density increase, making visual observation possible. The case is defined as precipitation.

Since the sol-gel method allows reactants to start from the liquid phase, reaction control is easy, chemical uniformity can be maintained, and various types of final products can be manufactured. The most commonly used metal alkoxides are alkoxysilanes, whose reactions are relatively easy to control compared to other metal alkoxides.

In general, alkoxysilanes are not soluble in water, so an organic solvent is used as a cosolvent. In the solution, an oligomeric precursor sol is formed through hydrolysis and condensation reactions of metal alkoxides as shown in the reaction formula below. After formation, an additional condensation reaction causes a sol-gel reaction to form a three-dimensional network gel.

Hydrolysis:

≡Si-OR + H ₂ O → ≡Si-OH + ROH

Condensation reaction:

≡Si-OH + ≡Si-OH → ≡Si-O-Si≡ + H ₂ O

≡Si-OH + ≡Si-OR → ≡Si-O-Si≡ + ROH

Particles grow in a solution to form an initial sol phase and then transition to a gel phase through growth and connection. The properties of the gel are greatly affected by the initial growth form of the particles. Therefore, controlling the growth method of these particles can be said to be a key technology in the sol-gel process.

When the particles in the solution are connected by forming metal-oxygen bonds through hydrolysis and condensation reactions to form a three-dimensional network structure, the viscosity of the solution rises rapidly and it loses fluidity as it passes the gel point. . This process is called gelation. In the gel formed in this way, the phenomenon in which dissolved monomers grow and thicken in the areas where particles are connected is called necking, and this process is called aging. Until this process, solvents added at the beginning of the reaction are present, and a process of removing these solvents is necessary to manufacture the product into a useful product.

Comparing the classic ceramic manufacturing process and the sol-gel process, the sol-gel process uses molecular compounds as the starting material, so it is easy to control the size of the intermediate product and the shape of the final product can be changed to nanoparticles (nano-gel). It can be manufactured in a variety of ways, such as powder, particles, fiber, thin film, monolith, and composite.

The application fields of these new materials include various optical coatings, protective coatings, functional films, structural materials, and component materials, and the field of most interest is the coating field that can provide various functionalities.

Hereinafter, the hollow fiber membrane surface-treated with a perfluorinated polyether-based coating agent and its manufacturing method will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

The present invention relates to a hollow fiber membrane containing hollow fibers; and a surface modification layer formed on the surface of the hollow fiber, wherein the surface modification layer is formed through a condensation reaction of perfluoropolyether silane, and the perfluoropolyether silane includes a perfluoropolyether chain; and a trialkoxy silane group bonded to the end of the perfluorinated polyether chain and having an alkoxy carbon number of 1 to 6.

Additionally, the perfluorinated polyether silane may be a compound represented by structural formula 1 below.

[Structural Formula 1]

In structural formula 1,

R is each a hydrogen atom or a C1 to C6 alkyl group,

A is a perfluoropolyether chain.

In addition, the surface-modified hollow fiber membrane includes a surface-modified layer in which the perfluorinated polyether silane further condenses with hydrogen atoms (H) on the surface of the hollow fiber to form a covalent bond with the hollow fiber, and has the structural formula 2 below: It may have a structure of

[Structural Formula 2]

In structural formula 2,

m is the number of repetitions of the repeat unit,

A is a perfluoropolyether chain.

In addition, the surface-modified hollow fiber membrane includes a surface-modified layer in which the perfluorinated polyether silane further condenses with the hydroxyl group (-OH) on the surface of the hollow fiber to form a covalent bond with the hollow fiber, and has the structural formula 3 below: It may have a structure of

[Structural Formula 3]

In structural formula 3,

n is the number of repetitions of the repeat unit,

A is a perfluoropolyether chain.

Additionally, the hollow fiber may be a polymer hollow fiber.

In addition, the polymer hollow fiber may include at least one selected from the group consisting of polypropylene hollow fiber, hydroxylated polypropylene (hydroxylated PP) hollow fiber, and polyvinylidene fluoride (PVDF) hollow fiber, preferably It may include one or more types selected from the group consisting of polypropylene hollow fibers and hydroxylated polypropylene hollow fibers, and more preferably may include polypropylene hollow fibers.

The present invention relates to the surface-treated hollow fiber membrane; and an absorbent. A membrane contactor for use in acid gas separation is provided.

In addition, the absorbent includes an amine compound and an additive, and the amine compound is monoethanolamine (MEA), 2-amino-2-hydroxymethyl-1,3-propanediol (2-amino-2-hydroxymethyl-1 ,3-propanediol, AHPD), 2-amino-2-methyl-1,3-propanediol (2-amino-2-methyl-1,3-propanediol, AMPD), 2-aminomethyl-2-hydroxymethyl -1,3-propanol (2-aminomethyl-2-hydroxymethyl-1,3-propanediol), 2-amino-1,1,1-ethanetriol (2-amino-1,1,1-ethanetriol), hydrazine (hydrazine), ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, diethanolamine, triethanolamine, and N-methyldiethanolamine, and the additive Glycine, sarcosine, piperazine, 2-(1-piperazinyl)-ethylamine (PZEA), aminomethyl propanol, AMP), potassium carbonate (K2CO3), trisodium phosphate (TSP), and tetraethylenepentamine (TEPA).

Preferably, the amine compound may include monoethanolamine (MEA), and the additive may include one or more selected from the group consisting of sarcosine and piperazine.

The additive is intended to improve the stability of the amine compound. By including the additive, the pH of the amine compound is reduced, thereby minimizing damage to the membrane, improving stability, and improving the physical properties of the absorbent.

Additionally, the acid gas may include one _or more types selected from the group consisting of carbon dioxide (CO ₂ ), nitrogen oxides _{( NO}

The present invention includes the steps of (a) preparing a coating solution containing perfluoropolyether silane; and (b) manufacturing a surface-modified hollow fiber membrane by coating the surface of the hollow fiber included in the hollow fiber membrane with the coating solution and forming a surface modification layer through a condensation reaction, wherein the perfluorinated polyether silane is perfluorinated polyether chain; and a trialkoxy silane group bonded to the end of the perfluorinated polyether chain and having an alkoxy carbon number of 1 to 6.

Additionally, the perfluorinated polyether silane may be a compound represented by structural formula 1 below.

[Structural Formula 1]

In structural formula 1,

R is each a hydrogen atom or a C1 to C6 alkyl group,

A is a perfluoropolyether chain.

In addition, in step (b), as shown in Scheme 1 below, the perfluorinated polyether silane (1) further condenses with the hydrogen atoms (H) on the surface of the hollow fiber (2) to form a covalent bond with the hollow fiber (2). This may be a step of manufacturing a surface-modified hollow fiber membrane 3 having a formed surface modification layer.

[Scheme 1]

In Scheme 1 above,

R is each a hydrogen atom or a C1 to C6 alkyl group,

A is a perfluoropolyether chain,

m is the number of repetitions of the repeating unit.

In addition, in step (b), as shown in Scheme 2 below, the perfluorinated polyether silane (1') undergoes an additional condensation reaction with the hydroxyl group (-OH) on the surface of the hollow fiber (2') to form the hollow fiber (2'). This may be a step of manufacturing a surface-modified hollow fiber membrane (3') having a surface-modified layer forming a covalent bond.

[Scheme 2]

In Scheme 2 above,

R is each a hydrogen atom or a C1 to C6 alkyl group,

A is a perfluoropolyether chain,

n is the number of repetitions of the repeating unit.

In addition, in the method of manufacturing a surface-modified hollow fiber membrane for a membrane contactor, before step (b), (b') the hollow fiber membrane containing the hollow fiber is surface treated with a surface treatment agent containing an acid and an oxidizing agent, thereby treating the surface of the hollow fiber membrane. It may further include forming a hydroxy group (-OH).

In addition, the coating solution includes a fluorine-based solvent, and the fluorine-based solvent is ethoxy-nonafluoropentane (C ₄ F ₉ OC ₂ H ₅ ), methoxy-nonafluorobutane (methoxy-nonafluorobutane, C ₄ F ₉ OC ₁ H ₅ ), decafluoro methoxy trifluoro methyl pentane (1,1,1,2,3,4,4,5,5,5-Decafluoro-3-methoxy-2-(trifluoromethyl ) pentane), hexafluorobenzene, octadecafluorooctane, octafluorocyclopentene, and hexadecafluoroheptane. and may preferably include ethoxy-nonafluoro pentane.

In addition, the method of manufacturing the surface-modified hollow fiber membrane includes, before step (b), (b") irradiating plasma to a hollow fiber membrane containing hollow fibers to form a hydrophilic surface of the hollow fiber membrane; It may further include: In this case, the hollow fiber may be a polymer hollow fiber, and the hollow fiber membrane may be a polymer hollow fiber membrane.

Figure 1 is a schematic diagram showing a method for separating acid gas from a membrane for a membrane contactor according to an embodiment of the present invention.

According to Figure 1, the present invention includes the steps of (1) preparing the membrane contactor; and (2) supplying acid gas to the membrane contactor to separate the acid gas.

In addition, step (2) includes (2-1) contacting the acid gas with the absorbent to absorb the acid gas into the absorbent; and (2-2) removing the acid gas absorbed in the absorbent.

Additionally, step (2-1) may be performed at 0°C to 80°C, and step (2-2) may be performed at 80°C to 150°C.

[Example]

Hereinafter, the present invention will be described with reference to preferred embodiments. However, this is for illustrative purposes only and does not limit the scope of the present invention.

Example 1: Preparation of surface-treated hollow fiber membrane (PP, KY-2%)

Mix ethoxy-nonafluoro pentane (HFE-7200 (3M)) with a 20 wt% solution of perfluoropolyether silane (ky-164, SHINESTU) to create a 2 wt% perfluoropolyether coating solution. Manufactured.

A hollow fiber membrane (PP hollow fiber membrane, Sepratech) made of polypropylene hollow fiber was immersed in the coating solution for 1 hour and reacted. Afterwards, the coating solution was removed and cured at 25°C and 40% RH for 24 hours.

After the curing, it was dried in a vacuum oven at 40°C for 4 hours to prepare a polypropylene hollow fiber membrane whose surface was modified with perfluorinated polyether.

Example 2: Preparation of surface-treated hollow fiber membrane (PP, KY-5%)

Mix ethoxy-nonafluoro pentane (HFE-7200 (3M)) with a 20 wt% solution of perfluoropolyether silane (ky-164, SHINESTU) to create a 5 wt% perfluoropolyether coating solution. Manufactured.

A hollow fiber membrane (PP hollow fiber membrane, Sepratech) made of polypropylene hollow fiber was immersed in the coating solution for 1 hour and reacted. Afterwards, the coating solution was removed and cured at 25°C and 40% RH for 24 hours.

After the curing, the polypropylene hollow fiber membrane whose surface was modified with perfluorinated polyether was manufactured by drying in a vacuum oven at 40°C for 4 hours.

Examples 3 and 4: Preparation of surface-treated hollow fiber membrane (H-PP, KY-2 %/H-PP KY-5 %)

Examples 3 and 4 were prepared by manufacturing hollow fiber membranes under the same conditions as Examples 1 and 2, respectively, but by forming hydroxy groups on the surface of the hollow fiber membrane before coating.

The formation of hydroxy groups on the surface of the hollow fiber membrane was carried out by the following method. After waiting until the high-temperature sulfuric acid solution produced by mixing sulfuric acid (80 to 99.99% by weight) with distilled water reaches room temperature, 0.01 g of KClO ₃ , an oxidizing agent, is added to 99.99 g of the sulfuric acid solution to prepare a liquid surface treatment agent. was manufactured. Next, the polypropylene (PP) hollow fiber membrane was immersed in the surface treatment agent for 10 minutes and reacted. At this time, if the reaction time is excessively long, the structure of the hollow fiber membrane may be destroyed and durability may rapidly decrease. Afterwards, the PP hollow fiber membrane was taken out, the excess surface treatment agent was washed off using distilled water, and the water remaining on the surface of the PP hollow fiber membrane was dried at 45°C for 4 hours in a vacuum oven to form a hydroxy group (-OH). A PP hollow fiber membrane was manufactured.

Comparative Example 1: Hollow fiber membrane (PP)

Comparative Example 1 is a hollow fiber membrane (PP hollow fiber membrane, Sepratec) made of polypropylene hollow fiber.

Comparative Example 2: Hollow fiber membrane (H-PP) with hydroxyl groups formed on the surface

After waiting until the high-temperature sulfuric acid solution produced by mixing sulfuric acid (80 to 99.99% by weight) with distilled water reaches room temperature, 0.01 g of KClO ₃ , an oxidizing agent, is added to 99.99 g of the sulfuric acid solution to prepare a liquid surface treatment agent. was manufactured. Next, the polypropylene (PP) hollow fiber membrane was immersed in the surface treatment agent for 10 minutes to react. At this time, if the reaction time is excessively long, the structure of the hollow fiber membrane may be destroyed and durability may rapidly decrease. Afterwards, the PP hollow fiber membrane was taken out, the excess surface treatment agent was washed off using distilled water, and the water remaining on the surface of the PP hollow fiber membrane was dried at 45°C for 4 hours in a vacuum oven to form a hydroxy group (-OH). PP hollow fiber membrane was used in Comparative Example 2.

The manufacturing conditions of Examples 1 to 4 and Comparative Examples 1 and 2 are summarized in Table 1 below.

division ky-164 ratio in coating solution Whether hydroxyl groups are formed on the surface Example 1 (PP, KY-2%) 2 % X Example 2 (PP, KY-5%) 5% X Example 3 (H-PP, KY-2%) 2 % ○ Example 4 (H-PP, KY-5%) 5% ○ Comparative Example 1 (PP, Pristine) - X Comparative Example 2 (H-PP) - ○

Device Example 1: Performance evaluation of membrane contactor

30 wt% of monoethanolamine (MEA) was used as an absorbent, and the absorbent (MEA) was supplied to the surface-treated hollow fiber membrane prepared according to Example 1 to evaluate the membrane contactor CO ₂ absorption performance.

Device Comparison Example 1: Performance evaluation of membrane contactor

The CO ₂ absorption performance of the membrane contactor was evaluated in the same manner as Device Example 1, except that the hollow fiber membrane prepared according to Comparative Example 1 was used instead of the surface-treated hollow fiber membrane prepared according to Example 1.

[Test example]

Test Example 1: SEM analysis

Figure 2 shows SEM images of hollow fiber membranes manufactured according to Example 1 (KY-164 Coating) and Comparative Example 1 (Pristine). In detail, images of the hollow fiber membranes of Example 1 and Comparative Example 1 were taken using SEM equipment (HITACHI SU8020) at magnifications of 0.3 k, 2.0 k, and 10.0 k, respectively.

According to Figure 2, it can be seen that Example 1, which was surface treated with perfluoropolyether silane (KY-164), did not show significant structural changes compared to Comparative Example 1, which was not surface treated.

Test Example 2: FT-IR analysis

Figure 3 shows the results of FT-IR analysis of the hollow fiber membrane prepared according to Example 1 (KY-164 coated PP) and Comparative Example 1 (Pristine PP). In detail, the transmittance of the hollow fiber membranes of Example 1 and Comparative Example 1 was analyzed using FT-IR equipment (JASCO FT/IR-4600). Since the specific chemical structure of a compound absorbs energy in a specific wavelength range, if it contains a component detected at a specific wavelength, the % value of the transmittance decreases, and through this, it is possible to determine which chemical component is present or how much is present. there is.

According to Figure 3, Comparative Example 1 (Pristine PP) did not absorb in the wavelength range of 900 to 1,300 cm ^-1 corresponding to CF and Si-F, while Example 1 (KY-164 coated PP) did not absorb the fluoro silane component. It can be seen that absorption occurs in the wavelength range of 900 to 1,300 cm ^-1 corresponding to phosphorus CF and Si-O, and the transmittance decreases.

Therefore, it can be confirmed that the perfluoropolyether was well coated on the surface of the PP membrane in Example 1, in which coating and curing were performed with a coating solution containing perfluoropolyether silane (KY-164).

Test Example 3: Checking water contact angle

Figure 4 is a graph showing the average value of the water contact angle of the hollow fiber membranes manufactured according to Examples 1 to 4 and Comparative Examples 1 and 2. The following experiment was conducted to confirm the hydrophobicity/hydrophilicity conduction of the hollow fiber membranes prepared according to Examples 1 to 4 and Comparative Examples 1 and 2. After placing the hollow fiber membrane under a syringe containing distilled water, 4 μL of distilled water was dropped on the surface of each hollow fiber membrane at a rate of 0.04 mL/min. When distilled water fell on the surface of the hollow fiber membrane, a photo was taken using a camera, and the contact angle between the hollow fiber membrane and distilled water was measured through the photo. Table 2 below lists the average water contact angle values of Examples 1 to 4 and Comparative Example 1.

division Comparative Example 1 (Pristine) Example 1
(PP, KY 2%) Example 2
(PP, KY 5%) Example 3
(H-PP, KY 2%) Example 4
(H-PP, KY 5%) Contact angle (˚) 119.4 128.4 127.1 128.8 127.6 Comparative Example 1
Contrast increase/decrease - +9 +7.7 +9.4 +7.9

According to Table 2 and Figure 4, the water contact angle of Comparative Example 1 (Pristine PP) without any treatment was measured to be 119.4 ˚, and in the case of Comparative Example 2 (H-PP) in which polypropylene was acid treated through a hydroxylation step, It was measured at 95.5 degrees. This is because -OH groups were formed on the PP membrane through the acid treatment process. The -OH group formed is hydrophilic and reduces the water contact angle of the hollow fiber membrane.

On the other hand, it was confirmed that Examples 1 to 4, which were surface treated with perfluoropolyether silane (KY-164), had an increased contact angle compared to Comparative Example 1, which was not surface treated, regardless of the presence or absence of acid treatment of polypropylene. You can.

In the case of polypropylene without acid treatment (Examples 1 and 2, PP), the C-H bond on the surface reacts with the Si-O-H of the silane group to form a Si-O-C bond, and the hollow fiber membrane surface contains perfluorinated polyether. A treatment layer is formed, and as a result, the hydrophobicity of the hollow fiber membrane surface appears to have increased significantly compared to before surface modification.

In the case of acid-treated polypropylene (Examples 3 and 4, H-PP), the hydroxyl group (-OH) on the surface forms a covalent bond with Si of the terminal silane group, forming perfluorinated polyether on the surface of the hollow fiber membrane. A surface treatment layer was formed, and as a result, the hydrophobicity of the hollow fiber membrane surface was found to be significantly increased compared to before surface modification.

Therefore, it can be seen that the contact angle increases as the surface is treated with perfluorinated polyether silane, regardless of the presence or absence of acid treatment, which indicates that the perfluorinated polyether silane is well coated on the membrane surface regardless of the presence or absence of acid treatment.

Test Example 4: Confirmation of carbon dioxide absorption rate and stability (duration time)

Figure 5 is a schematic diagram of an analysis device for measuring the carbon dioxide absorption rate of a membrane contactor manufactured according to one embodiment of the present invention, and Figure 6 shows Device Example 1 (PFE Coated Hollow Fiber) and Device Comparative Example 1 (Non-coated) This is a graph showing the carbon dioxide absorption rate and stability of the membrane contactor according to hollow fiber.

With reference to Figure 5, the carbon dioxide absorption rate and stability of the membrane contactors according to Device Example 1 (PFE Coated Hollow Fiber) and Device Comparative Example 1 (Non-coated Hollow Fiber) were measured. In detail, the experiment was conducted using a membrane contactor and GC (gas chromatography), and the experiment was conducted as follows.

Considering that the concentration of CO ₂ in waste gas generated from a typical power plant is 15%, 15 vol% of CO ₂ is continuously flowed inside the hollow fiber membrane at a flow rate range of 5 to 100 mL/min through an MFC (mass flow controller). At the same time, an absorbent prepared by mixing 70 wt% of distilled water and 30 wt% of MEA (monoethanolamine) is continuously flowed to the outside of the hollow fiber membrane to form a gas phase inside the hollow fiber membrane and a liquid phase outside the hollow fiber membrane. did.

At this time, a certain amount of flowing CO ₂ gas is removed from the membrane contactor, and the remaining amount flows into the external GC through the membrane contactor. Afterwards, the GC measured the CO ₂ concentration using a TCD (thermal conductivity detector) detector and confirmed the removal rate.

After confirming the initial area value by directly analyzing 15 vol% CO ₂ in the GC using a by-pass line, the surface-modified hollow fiber membrane module was installed in the test device. Afterwards, 15 vol% of CO ₂ was injected at a rate of 20 mL/min using an MFC, and the absorption liquid was injected in crossing directions at a rate of 10 mL/min using a liquid pump. Accordingly, the hollow fiber membrane was formed in the membrane contactor. As a boundary, a gas phase was formed inside and a liquid phase was formed outside. Therefore, a certain amount of CO ₂ out of 15 vol% of CO ₂ in the gas phase passes through the pores of the hollow fiber membrane and is absorbed by 30 wt% of MEA in the liquid phase. Through this process of CO ₂ being absorbed, CO ₂ in the exhaust gas is absorbed. A certain amount is removed, and the excess CO ₂ of the remaining gas that passed through the membrane contactor enters the GC and is analyzed. During the analysis process, the concentration of CO ₂ was expressed as an area value, and the CO ₂ absorption rate (removal rate) was confirmed by comparing this value with the initial area value of CO ₂ .

According to FIG. 6, in the case of Device Comparative Example 1 including an untreated hollow fiber membrane, it can be seen that the CO ₂ removal efficiency rapidly decreases due to wetting after 5 days.

On the other hand, in the case of device example 1 including a hollow fiber membrane surface treated with perfluoropolyether silane (KY-164), the CO ₂ removal rate was more than 90% and the duration was maintained at more than 21 days. You can check that.

Therefore, the hollow fiber membrane for a membrane contactor according to the present invention has a surface modified by a surface modification layer containing perfluoropolyether silane, resulting in less wetting phenomenon and higher durability, so that when used in a membrane contactor, the membrane contactor It has the effect of improving long-term stability.

The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

Claims (19)

A hollow fiber membrane containing hollow fibers; and
It includes a surface modification layer formed on the surface of the hollow fiber,
The surface modification layer is formed by condensation reaction of perfluoropolyether silane,
The perfluorinated polyether silane is a perfluorinated polyether chain; And a trialkoxy silane group bonded to the end of the perfluorinated polyether chain and having an alkoxy carbon number of 1 to 6,
A surface-modified hollow fiber membrane, wherein the perfluorinated polyether silane is a compound represented by structural formula 1 below:
[Structural Formula 1]

In structural formula 1,
R is each a hydrogen atom or a C1 to C6 alkyl group,
A is a perfluoropolyether chain. delete According to paragraph 1,
The surface-modified hollow fiber membrane includes a surface-modified layer in which the perfluorinated polyether silane undergoes an additional condensation reaction with hydrogen atoms (H) on the surface of the hollow fiber to form a covalent bond with the hollow fiber, and has the structure of structural formula 2 below: A surface-modified hollow fiber membrane characterized by having:
[Structural Formula 2]

In structural formula 2,
m is the number of repetitions of the repeat unit,
A is a perfluoropolyether chain. According to paragraph 1,
The surface-modified hollow fiber membrane includes a surface-modified layer in which the perfluorinated polyether silane further condenses with the hydroxyl group (-OH) on the surface of the hollow fiber to form a covalent bond with the hollow fiber, and has the structure of structural formula 3 below A surface-modified hollow fiber membrane characterized by having:
[Structural Formula 3]

In structural formula 3,
n is the number of repetitions of the repeat unit,
A is a perfluoropolyether chain. According to paragraph 1,
A surface-modified hollow fiber membrane, characterized in that the hollow fiber is a polymer hollow fiber. According to clause 5,
The surface-modified hollow fiber membrane is characterized in that the polymer hollow fiber includes at least one selected from the group consisting of polypropylene hollow fiber, hydroxylated polypropylene hollow fiber, and polyvinylidene fluoride (PVDF) hollow fiber. . A surface-modified hollow fiber membrane according to claim 1; and
absorbent;
and a membrane contactor for use in acid gas separation. In clause 7,
The absorbent includes an amine compound and an additive,
The amine compound is monoethanolamine (MEA), 2-amino-2-hydroxymethyl-1,3-propanediol (2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), 2-amino-2 -Methyl-1,3-propanediol (2-amino-2-methyl-1,3-propanediol, AMPD), 2-aminomethyl-2-hydroxymethyl-1,3-propanol (2-aminomethyl-2- hydroxymethyl-1,3-propanediol), 2-amino-1,1,1-ethanetriol, hydrazine, ethylenediamine, diethylenetriamine, triamine Contains at least one selected from the group consisting of ethylenetetraamine, tetraethylenepentamine, diethanolamine, triethanolamine, and N-methyldiethanolamine,
The additives include glycine, sarcosine, piperazine, 2-(1-piperazinyl)-ethylamine (PZEA), aminomethyl propanol ( Characterized by containing at least one selected from the group consisting of aminomethyl propanol (AMP), potassium carbonate (K ₂ CO ₃ ), trisodium phosphate (TSP), and tetraethylenepentamine (TEPA). Membrane contactor. In clause 7,
A membrane contactor, wherein the acid gas includes at least one selected from the group consisting of carbon dioxide (CO ₂ ), nitrogen oxide (NO _x ), hydrogen sulfide (H ₂ S) and sulfur oxide (SO _x ). (a) preparing a coating solution containing perfluoropolyether silane; and
(b) coating the surface of the hollow fiber included in the hollow fiber membrane with the coating solution and forming a surface modification layer through a condensation reaction to produce a surface-modified hollow fiber membrane;
The perfluorinated polyether silane is a perfluorinated polyether chain; And a trialkoxy silane group bonded to the end of the perfluorinated polyether chain and having an alkoxy carbon number of 1 to 6,
Method for producing a surface-modified hollow fiber membrane in which the perfluorinated polyether silane is a compound represented by structural formula 1 below:
[Structural Formula 1]

In structural formula 1,
R is each a hydrogen atom or a C1 to C6 alkyl group,
A is a perfluoropolyether chain. delete According to clause 10,
In step (b), the perfluorinated polyether silane (1) undergoes an additional condensation reaction with the hydrogen atoms (H) on the surface of the hollow fiber (2) to form a covalent bond with the hollow fiber (2), as shown in Scheme 1 below. A method for manufacturing a surface-modified hollow fiber membrane, characterized in that it is a step of manufacturing a surface-modified hollow fiber membrane (3) having a surface modification layer:
[Scheme 1]

In Scheme 1 above,
R is each a hydrogen atom or a C1 to C6 alkyl group,
A is a perfluoropolyether chain,
m is the number of repetitions of the repeating unit. According to clause 10,
In step (b), as shown in Scheme 2 below, perfluorinated polyether silane (1') undergoes an additional condensation reaction with the hydroxyl group (-OH) on the surface of the hollow fiber (2') and covalently bonds to the hollow fiber (2'). A method for manufacturing a surface-modified hollow fiber membrane, characterized in that it is a step of manufacturing a surface-modified hollow fiber membrane (3') having a surface modification layer formed:
[Scheme 2]

In Scheme 2 above,
R is each a hydrogen atom or a C1 to C6 alkyl group,
A is a perfluoropolyether chain,
n is the number of repetitions of the repeating unit. According to clause 10,
Before step (b), the method for producing the surface-modified hollow fiber membrane,
(b') surface treating a hollow fiber membrane containing hollow fibers with a surface treatment agent containing an acid and an oxidizing agent to form a hydroxy group (-OH) on the surface of the hollow fiber membrane; surface modification characterized in that it further comprises a. Manufacturing method of hollow fiber membrane. According to clause 10,
The coating solution contains a fluorine-based solvent,
The fluorine-based solvent is 1-ethoxy-nonafluorobutane (C ₄ F ₉ OC ₂ H ₅ ), 1-methoxy-nonafluorobutane (C ₄ F ₉ OCH) ₃ ), decafluoro methoxy trifluoro methyl pentane (1,1,1,2,3,4,4,5,5,5-Decafluoro-3-methoxy-2-(trifluoromethyl) pentane), hexafluoro A surface-modified product characterized in that it contains at least one member selected from the group consisting of Hexafluorobenzene, Octadecafluorooctane, Octafluorocyclopentene, and Hexadecafluoroheptane. Manufacturing method of hollow fiber membrane. According to clause 10,
Before step (b), the method for producing the surface-modified hollow fiber membrane,
(b") irradiating plasma to a hollow fiber membrane containing hollow fibers to form a surface of the hollow fiber membrane to be hydrophilic. (1) Preparing a membrane contactor according to paragraph 7; and
(2) supplying acid gas to the membrane contactor to separate the acid gas;
Method for separating acid gas containing. According to clause 17,
Step (2) above is
(2-1) contacting the acid gas with the absorbent to absorb the acid gas into the absorbent; and
(2-2) A method for separating acid gas, comprising the step of removing the acid gas absorbed in the absorbent. According to clause 18,
The step (2-1) is performed at 0°C to 80°C,
The step (2-2) is a method of separating acid gas, characterized in that it is performed at 80 ℃ to 150 ℃.