KR102477822B1 - Carbon monoxide facilitated transport gas separation membrane and its manufacturing method - Google Patents

Abstract

The present invention relates to a gas separation membrane and a manufacturing method thereof. More specifically, the present invention is a gas separation membrane comprising an acrylic selective layer formed of a composite including a copolymer represented by Formula 1, a silver salt and an ionic liquid, has a solid state, and has an excellent selection for carbon monoxide It relates to a gas separation membrane with significantly improved expedited transport performance by realizing conductivity and permeability, and a method for manufacturing the same.

Description

Carbon monoxide facilitated transport gas separation membrane and its manufacturing method

The present invention relates to a gas separation membrane and a manufacturing method thereof. In particular, it relates to a selective carbon monoxide-promoted transport gas separation membrane and a manufacturing method thereof.

Carbon monoxide (CO) can be produced into various carbon compounds through biological and chemical conversion, and is used as a raw material for producing compounds such as alcohol, aldehyde, and acid, and is a gas with a very wide range of applications.

Carbon monoxide is included in a large amount along with nitrogen in blast furnace gas (BFG) or Linz-Donawitz converter gas (LDG) among by-product gases generated in the steel industry. Due to the lack of technology, it is mainly used for power generation with low added value.

As conventional technologies for separating and recovering carbon monoxide, a gas adsorption method using copper chloride, cryogenics, a Cosorb method using CuAlCl ₄ and an organic solvent, and a VPSA method using an adsorbent have been developed and utilized. However, when carbon monoxide is separated from steel by-product gas using the deep cooling method, the boiling points of carbon monoxide and nitrogen are similar, making selective separation difficult (boiling point, CO: -191.5℃, N ₂ : -195.9℃), and CuAlCl ₄ and toluene In the case of the absorption method used, it is very sensitive to moisture, requiring a strict pretreatment process, requiring high heat energy when regenerating the absorbent, and having economic and environmental problems due to leakage of toxic solution due to high temperature use. In addition, in the case of an adsorbent made by mixing a porous material such as zeolite or activated carbon with CuCl ₂ , it is difficult to maintain selectivity and adsorption capacity in a multi-component mixed gas state, which limits industrial use in terms of efficiency.

In order to solve the above problems and separate carbon monoxide with low cost and high efficiency, a method using a separation membrane has been developed, but this is a liquid separation membrane, which is a supported ionic liquid membrane (SILM) impregnated with an ionic liquid in a substrate As a membrane), the impregnated liquid may leak by external pressure, and it has problems in handling and stability.

Accordingly, it is necessary to develop a solid state gas separation membrane having excellent performance in selective separation of carbon monoxide and improved handling and stability.

Korean Patent Publication No. 10-2013-0134500 (2012.05.31.)

An object of the present invention is to provide a solid state gas separation membrane with excellent performance in selective separation of carbon monoxide and improved handling and stability because it is not impregnated with an ionic liquid and a method for manufacturing the same.

Specifically, a solid gas separation membrane with improved selective permeability and accelerated transport performance of carbon monoxide by including a selective layer formed by coating a composite including a copolymer represented by Formula 1, a silver salt, and an ionic liquid on the surface of a porous substrate, and It is to provide a manufacturing method thereof. In addition, it is to provide a gas separation membrane capable of separating and recovering carbon monoxide with low energy consumption and high efficiency.

[Formula 1]

(In Formula 1 above,

The R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ ,

The R _{2 and} R ₂ 'are the same as or different from each other, and are each independently a straight-chain or branched C2-C6 alkylene group,

Wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group,

Wherein x = a natural number from 1 to 300, y = a natural number from 1 to 600, and z = a natural number from 1 to 3.)

The gas separation membrane of the present invention for solving the above problems includes a porous substrate; and an acrylic selection layer formed on the surface of the porous substrate.

In the gas separation membrane according to an embodiment of the present invention, the acrylic selective layer may be formed by coating a composite including a copolymer represented by Formula 1 below, a silver salt, and an ionic liquid.

[Formula 1]

(In Formula 1 above,

Wherein R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ , wherein R _{2 and} R ₂ 'are the same as or different from each other, and are each independently straight-chain or branched C2 to C6 is an alkylene group, wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group, where x = a natural number of 1 to 300, y = a natural number of 1 to 600, and z = a natural number of 1 to 3.)

In the gas separation membrane according to an embodiment of the present invention, the copolymer may be obtained by reacting the compound represented by Chemical Formula 2 and the compound represented by Chemical Formula 3 at a weight ratio of 7:3 to 3:7.

[Formula 2]

(In Formula 2, R ₁ is each independently selected from hydrogen and -CH ₃ , R _{2 and} R ₂ ′ are the same as or different from each other, and are each independently a straight-chain or branched C2-C6 alkylene group. And, wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group, and z= is a natural number of 1 to 3.)

[Formula 3]

(In Formula 3, R ₁ 'are independently hydrogen or -CH ₃ .)

In the gas separation membrane according to an embodiment of the present invention, the ionic liquid is composed of organic cations and anions, and the cations include dialkylimidazolium, alkylpyridinium, quaternary ammonium, and quaternary phosphonium. Any one cation selected, and the anion includes NO ₃ ^- , BF ₄ ^- , PF ₆ ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , TfO-(Trifluoromethanesulfonate), Tf ₂ N-(Trifluoromethanesulfonylamide) and CH ₃ It may be any one anion selected from CH(OH)CO ₂ -(L-lactate).

In the gas separation membrane according to an embodiment of the present invention, the composite may include 200 to 500 parts by weight of a silver salt and 20 to 50 parts by weight of an ionic liquid based on 100 parts by weight of the copolymer represented by Formula 1 there is.

In the gas separation membrane according to an embodiment of the present invention, an additional gutter layer may be further formed on the surface of the porous substrate.

In the gas separation membrane according to an embodiment of the present invention, the gutter layer may include a siloxane-based polymer or a substituted polyacetylene.

In the gas separation membrane according to an embodiment of the present invention, the thickness of the selection layer may be 300 nm to 1,000 nm.

In the gas separation membrane according to an embodiment of the present invention, the gas separation membrane may have a CO/N ₂ selectivity of 2.0 or more at 25 °C 1 bar.

In the gas separation membrane according to an embodiment of the present invention, the gas separation membrane may be used to selectively separate carbon monoxide through facilitated transport.

The present invention includes a method for manufacturing the gas separation membrane described above.

A method for manufacturing a gas separation membrane according to the present invention includes preparing a composite including a copolymer represented by Chemical Formula 1, a silver salt, and an ionic liquid; and forming an acrylic selective layer by coating and drying the composite on the surface of a porous substrate.

[Formula 1]

(In Formula 1, R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ , wherein R _{2 and} R ₂ ' are the same as or different from each other, and each independently a straight-chain or A branched C2~C6 alkylene group, wherein R ₃ is each independently hydrogen or a C1~C3 alkyl group, wherein x=a natural number of 1 to 300, y=a natural number of 1 to 600, z=1 to 3 is a natural number.)

In the method for manufacturing a gas separation membrane according to an embodiment of the present invention, the step of forming an additional gutter layer on the surface of the porous substrate may be further included before the step of forming the acrylic selective layer.

The gas separation membrane according to the present invention includes a selective layer formed of a composite including a copolymer represented by Formula 1 below, a silver salt, and an ionic liquid, so that both the permeability and selectivity of carbon monoxide are improved, and the facilitated transport performance is excellent. have an advantage

In addition, the selective layer can be formed simply by coating and drying the composite, so it is easy to have a large area and large capacity, and as a solid gas separation membrane that is not impregnated with an ionic liquid, it is easy to handle, work stability and operation stability has this excellent advantage.

[Formula 1]

(In Formula 1 above,

The R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ ,

The R _{2 and} R ₂ 'are the same as or different from each other, and are each independently a straight-chain or branched C2-C6 alkylene group,

Wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group,

Wherein x = a natural number from 1 to 300, y = a natural number from 1 to 600, and z = a natural number from 1 to 3.)

1 shows a schematic diagram of the synthesis of the polymer prepared in Example 1 of the present invention.
Figure 2 shows the structure and crystallinity of the polymers prepared in Examples 1 to 3 of the present invention by Fourier transform infrared spectroscopy (FT ^- IR), Nuclear magnetic resonance spectroscopy (1H- NMR), XRD (X-ray diffraction) and differential scanning calorimeter (DSC) analysis results are shown in FIGS. 2(a) to 2(d), respectively.
3 is a cross section of the gas separation membrane prepared in Examples 1 to 3 and Comparative Examples 1 and 3 of the present invention observed through a scanning electron microscope (SEM) and shown in FIG.
Figure 4 shows the surface of the gas separation membrane prepared in Examples 1 to 3 of the present invention observed through a transmission electron microscope (Transmission Electron Microscope, TEM).
5 shows the result of analyzing the interaction between molecules in the acrylic selective layer of the gas separation membrane prepared in Examples 1 to 3 of the present invention with a Fourier transform infrared spectroscopy (FT-IR) spectrometer.

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

Also, unless defined otherwise, all technical terms and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms used in the description in the present invention are merely to effectively describe specific embodiments and are not intended to limit the present invention.

Also, the singular forms used in the specification and appended claims may be intended to include the plural forms as well, unless the context dictates otherwise.

In addition, when a certain component is said to "include", this means that it may further include other components without excluding other components unless otherwise stated.

The present invention for achieving the above object provides a gas separation membrane and a manufacturing method thereof.

The present inventors have intensified research on a method for manufacturing a solid gas separation membrane with excellent performance for selective separation of carbon monoxide.

Accordingly, a composite including a copolymer represented by Formula 1, a silver salt, and an ionic liquid is coated on the surface of a porous substrate to form an acrylic selective layer, thereby forming a solid-state and mixing carbon monoxide and nitrogen In the gas, it was confirmed that gas separation having excellent carbon monoxide selectivity and excellent accelerated transport performance was possible, and the present invention was completed.

[Formula 1]

In Formula 1, R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH 3 , and R ₂ and R ₂ ' are the same as or different from each other, and are each independently linear or branched. A C2~C6 alkylene group, wherein R ₃ are each independently hydrogen or a C1~C3 alkyl group,

Wherein x = a natural number of 1 to 300, y = a natural number of 1 to 600, and z = a natural number of 1 to 3. The x may be preferably a natural number of 30 to 200, and the y may be a natural number of 300 to 500.

The compound represented by Formula 1 may preferably be of Formula 1a below.

[Formula 1a]

In Formula 1a, x = a natural number of 35 to 200, y = a natural number of 350 to 500, and z = a natural number of 1 to 3.

Hereinafter, the gas separation membrane of the present invention and its manufacturing method will be described.

The gas separation membrane of the present invention includes a porous substrate; and an acrylic selective layer formed on the surface of the porous substrate.

The porous substrate is a material having known porosity, but any material used as a separator can be used, and specifically, a material selected from poly sulfone, poly ether sulfone, and poly imide It may be formed of one or more types of polymers, preferably formed of polysulfone, but it is not limited as long as it is a porous substrate. In addition, the porous substrate may further include an additional gutter layer on the surface in order to realize higher gas permeability. In this case, as a preferred embodiment, the acrylic selective layer may be formed on the surface of the gutter layer.

The gutter layer may include a siloxane-based polymer or a polyacetylene-based polymer, and the siloxane-based polymer may include polydimethylsiloxane (PDMS) and the like, and the polyacetylene-based polymer may include poly[ 1-(trimethylsilyl)-1-propyne] (poly[1-(trimethylsilyl)-1-propyne], PTMSP), Poly(4-methyl-1-pentene) , PMP) and poly (tert-butylacetylene) (poly (tert-butylacetylene), PTBA), but may include one or more selected from the like, but is not limited thereto.

The acrylic selective layer may be formed by coating a composite including a copolymer represented by Formula 1 below, a silver salt, and an ionic liquid.

[Formula 1]

In Formula 1, R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ , and R _{2 and} R ₂ ' are the same as or different from each other, and are each independently linear or branched chain. A topographical C2~C6 alkylene group, wherein each R ₃ is independently hydrogen or a C1~C3 alkyl group,

Wherein x = a natural number of 1 to 300, y = a natural number of 1 to 600, and z = a natural number of 1 to 3. The x may be preferably a natural number of 30 to 200, and the y may be a natural number of 300 to 500.

The copolymer represented by Chemical Formula 1 may be obtained by reacting the compound represented by Chemical Formula 2 with the compound represented by Chemical Formula 3 at a weight ratio of 9:1 to 1:9, preferably 7:3 to 3:7. may have reacted with

[Formula 2]

In Formula 2, R ₁ is each independently selected from hydrogen and -CH ₃ , R _{2 and} R ₂ ′ are the same as or different from each other, and are each independently a straight-chain or branched C2-C6 alkylene group. , wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group, and z= is a natural number of 1 to 3.

[Formula 3]

In Formula 3, R ₁ 'are independently hydrogen or -CH ₃ .

The copolymer represented by Chemical Formula 1 above contains all of the carbonyl groups (C=O) in the repeating unit, so that a point where bonding can be made by a chemically strong mutual coordination reaction with silver ions of a silver salt described later Since the silver salt can be uniformly dispersed, the accelerated transport performance of carbon monoxide in the mixed gas can be further improved.

In particular, the acrylic selective layer according to an embodiment of the present invention controls the ratio of the repeating unit of the compound represented by Formula 2 and the repeating unit of the compound represented by Formula 3 in the copolymer represented by Formula 1 described above. Accordingly, it is possible to control the strength of the mutual coordination action between carbonyl (C=O) groups and silver ions, and to control the carbon monoxide (CO) selectivity and transmittance of the prepared acrylic selective layer. In addition, the carbonyl group (C=O) included in the repeating unit has a strong mutual coordination action with the Ag ion of the silver salt, so that the structure of the matrix of the acrylic selective layer is further densified and the gas selectivity can be further improved, which is preferable.

The copolymer represented by Formula 1 may have a weight average molecular weight (Mw) of 10,000 to 100,000 g/mol, preferably 40,000 to 95,000 g/mol.

The silver salt may be selected from the group consisting of AgNO ₃ , AgBF ₄ , AgPF ₆ , AgSO ₃ CF ₃ , AgClO ₄ and AgSbF ₆ , preferably AgBF ₄ .

The ionic liquids (Ionic Liquids, ILs) refer to metal cations and non-metal anions that exist as a liquid at a temperature of 100 ° C or less, and the ionic liquids are composed of organic cations and anions, and the cations include It is any one cation selected from dialkylimidazolium, alkylpyridinium, quaternary ammonium and quaternary phosphonium, and the anion includes NO ₃ ^- , BF ₄ ^- , PF ₆ ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , TfO ^- (Trifluoromethanesulfonate), Tf ₂ N ^- (Trifluoromethanesulfonylamide), and CH ₃ CH (OH) CO ₂ ^- (L-lactate) may be any one anion selected.

In particular, as the ionic liquid, BMIM ⁺ BF ₄ ^- (1-butyl-3-methylimidazoliumtetrafluoroborate), BMIM ⁺ NO ₃ ^- (1-butyl-3-methylimidazolium nitrate), BMIM ⁺ PF ₆ ^- (1-butyl-3- methylimidazolium hexafluorophosphate), EMIM ⁺ BF ₄ ^- (1-ethyl-3-methylimidazolium tetrafluoroborate) and HMIM ⁺ NO ₃ ^- (1-hexyl-3-methylimidazolium nitrate).

When the ionic liquid is included, aggregation of the copolymer represented by Chemical Formula 1 and the silver salt can be suppressed, and the silver salt can be homogeneously dispersed, which is more preferable.

The composite is not particularly limited, but may include, for example, 200 to 800 parts by weight of a silver salt and 20 to 80 parts by weight of an ionic liquid based on 100 parts by weight of the copolymer represented by Formula 1 described above, preferably may be included in 300 to 500 parts by weight of a silver salt and 30 to 50 parts by weight of an ionic liquid, based on 100 parts by weight of the copolymer represented by Formula 1. It is preferable that the gas selectivity and permeability of the acrylic coating layer prepared in the above range are further improved, and in particular, the permeability and selectivity of carbon monoxide (CO) of the acrylic selective layer are preferably improved, so that facilitated transport can be more preferably implemented. but is not necessarily limited thereto.

In the composite forming the acrylic selective layer of the present invention, the silver salt in the matrix formed of the copolymer represented by the above-mentioned formula (1) further increases the solubility of carbon monoxide (CO), and the ionic liquid (IL) is excessively It is more preferable that it is possible to form an acrylic selective layer in which silver ions are homogeneously dispersed without sacrificing free volume or forming structural defects by suppressing coordination bonds.

In particular, the ionic liquid improves the solubility and selectivity of carbon monoxide (CO), thereby realizing easy transport of carbon monoxide (CO) molecules through the acrylic selective layer, thereby enabling accelerated transport.

The acrylic selective layer may be formed by coating the above-described composite on the surface of a porous substrate, and the thickness thereof is not particularly limited as long as the object of the present invention is achieved, but, for example, 100 nm to 50 μm It may be, preferably may be from 100 nm to 2,000 nm, more preferably from 300 nm to 1,000 nm, and even more preferably from 500 nm to 800 nm, but is not limited thereto.

A gas separation membrane according to an embodiment of the present invention may be used to selectively separate carbon monoxide (CO) through facilitated transport.

The gas separation membrane according to a preferred embodiment of the present invention may have a CO/N ₂ selectivity of 2.0 or more at 25 °C 1 bar, preferably a selectivity of 2.2 or more, more preferably 7.0 or more, or even more. Preferably it may be 10.0 or more. The selectivity may be adjusted according to the thickness of the acrylic selection layer described above.

Hereinafter, a method for manufacturing a gas separation membrane according to the present invention will be described in detail.

A method for manufacturing a gas separation membrane according to an embodiment of the present invention includes preparing a composite including a copolymer represented by Chemical Formula 1, a silver salt, and an ionic liquid; and forming an acrylic selective layer by coating and drying the composite on the surface of the porous substrate.

[Formula 1]

In Formula 1, R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ , and R ₂ and R ₂ ' are the same as or different from each other, and are each independently linear or branched chain. A topographical C2~C6 alkylene group, wherein R ₃ is each independently hydrogen or a C1~C3 alkyl group, wherein x = a natural number of 1 to 300, y = a natural number of 1 to 600, and z = 1 to 3 is a natural number The x may be preferably a natural number of 30 to 200, and the y may be a natural number of 300 to 500.

The copolymer represented by Chemical Formula 1 may be obtained by reacting the compound represented by Chemical Formula 2 with the compound represented by Chemical Formula 3 at a weight ratio of 9:1 to 1:9, preferably 7:3 to 3:7. may have reacted with

[Formula 2]

In Formula 2, R ₁ is each independently selected from hydrogen and -CH ₃ , R _{2 and} R ₂ ′ are the same as or different from each other, and are each independently a straight-chain or branched C2-C6 alkylene group. , wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group, and z= is a natural number of 1 to 3.

[Formula 3]

In Formula 3, R ₁ 'are independently hydrogen or -CH ₃ .

The reaction may preferably be to use a free radical polymerization reaction, and the free radical polymerization reaction may be carried out without limitation within conditions that can be understood by those skilled in the art, and preferably, ethanol, acetone, Any one or a mixture thereof selected from acetonitrile and ethyl acetate may be used, and azobisisobutyronitrile (AIBN) may be used as an initiator, but is not limited thereto.

In the step of preparing the composite, the copolymer, the silver salt, and the ionic liquid may be the same as those described above, and the composite may further include a solvent.

The solvent is not limited as long as it can dissolve the copolymer and the silver salt, but specifically water, ethanol, methanol, acetonitrile, dichloromethane (MC), dimethylformamide (DMF) and N-methylpyrrolidone ( NMP), etc., or a mixed solution thereof may be used, but is not limited thereto.

The solid content in the composite may be 1 to 50% by weight, preferably 5 to 20% by weight, but it can be appropriately adjusted depending on the coating property, workability, and thickness of the acrylic selective layer to be prepared.

In the step of preparing the acrylic selective layer, the same porous substrate as described above may be used, and as a method of coating the composite on the surface of the porous substrate, coating and drying may be performed by a known method. can

Examples of the coating include a bar coating method, a rod coating method, a die coating method, a wire coating method, a comma coating method, a micro gravure/gravure method, and a dip ) coating method, spray method, inkjet coating method, or a method in which they are mixed or modified, and the like may be used. At this time, the coating thickness may be 100 nm to 50 μm, preferably 100 nm to 2,000 nm, more preferably 300 nm to 1,000 nm, and even more preferably 500 nm to 800 nm. nm, but is not limited thereto.

In addition, the drying may be drying at 10 ° C. to 70 ° C. for 6 hours to 36 hours, preferably at 20 ° C. to 50 ° C. for 12 hours to 24 hours, but is not limited thereto. At this time, the content of the solvent in the gas separation membrane may be less than 0.5% by weight.

As a preferred embodiment of the present invention, a gas separation membrane may be manufactured by coating and drying the above-described composite on the surface of a gutter layer of a porous substrate further provided with a gutter layer on the surface.

In the case of manufacturing as described above, the gas permeability is further improved by the gutter layer, and the carbon monoxide selectivity and the accelerated transport function of the acrylic selective layer are further improved, so that more improved gas separation performance can be realized.

As described above, the gas separation membrane according to an embodiment of the present invention is an acrylic selective layer formed by coating and drying a composite containing a copolymer represented by Formula 1, a silver salt, and an ionic liquid on the surface of a porous substrate By including, it is possible to implement a solid state separation membrane, unlike a conventional liquid separation membrane prepared by impregnating a porous substrate with an ionic liquid. In addition, the gas separation membrane of the present invention further improves ease of handling, stability, and applicability, and has excellent selectivity for carbon monoxide (CO), so that gas separation performance in a mixed gas containing carbon monoxide is remarkably improved. .

In particular, the gas separation membrane according to an embodiment of the present invention has an excellent effect of accelerated transport of carbon monoxide due to simultaneous increase in carbon monoxide permeability and CO/N ₂ selectivity.

[Formula 1]

In Formula 1, R1 and R1' are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ , wherein R ₂ and R ₂ 'are the same as or different from each other, and are each independently linear or branched A C2~C6 alkylene group, wherein R ₃ is each independently hydrogen or a C1~C3 alkyl group, wherein x = a natural number of 1 to 300, y = a natural number of 1 to 600, and z = a natural number of 1 to 3 .

The present invention will be described in more detail based on the following Examples and Comparative Examples. However, the following Examples and Comparative Examples are only one example for explaining the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Test method]

1. Measurement of gas separation performance

The pure gas separation performance of the prepared gas separation membrane was measured using a constant pressure/variable volume device (Airrane Co. Ltd., Korea). The permeation experiment was performed with a flat plate permeation cell having an effective area of 10.2 cm ² at 25 °C, and each gas was measured using a gas permeation unit (GPU) (1 GPU = 10 ⁻⁶ cm ³ _STP (s cm ² cmHg) ⁻¹ ). The transmittance of is expressed.

The CO/N ₂ selectivity of the gas separation membrane was calculated as a transmittance ratio.

2. Measurement of characteristics of gas separation membrane

The chemical structure of the polymerized copolymer and the interaction between the components were analyzed by Fourier transform-infrared (FT-IR) spectroscopy (Spectrum 100, Perkin Elmer, USA) in the frequency range of 2,000 to 6,00 cm ^-1 . was measured by

^{1 H} nuclear magnetic resonance (NMR) (AVANCE III HD 400, Bruker, Germany) measurement analyzed the composition of the copolymer using deuterated dimethyl sulfoxide (DMSO-d6) as a solvent. The glass transition temperature (Tg) of the copolymer was measured by differential scanning calorimetry (DSC) (Discovery DSC, TA Instrument, USA) at a heating rate of 10 °C/min under a nitrogen atmosphere over a temperature range of -75 °C to -150 °C. measured.

XRD of the copolymer was measured in the 2θ range of 5 ° to 35 ° at a scanning speed of 3 °/min using a high-resolution X-ray diffractometer (SmartLab, Rigaku, Japan).

The cross-sectional shape of the gas separation membrane was measured by field emission (FE)-SEM (JSM-7001F, JEOL Ltd., Japan), and the surface shape of the gas separation membrane was measured by transmission electron microscope (TEM) (JEM-F200, JEOL Ltd., Japan) was used.

[Example 1]

Dissolve 7 g of 2-hydroxypropyl-2-(methacryloyloxy)ethyl phthalate (HMEP) and 3 g of acrylic acid (AA) in 50 mL of acetonitrile/ethanol mixed solvent (60% acetonitrile, 40% ethanol) After that, 0.002 g of azobisisobutyronitrile (AIBN) was added and purged with N ₂ for 1 hour, followed by reaction in an oil bath at 70 °C for 24 hours while stirring. The reaction solution was poured into an excess of distilled water with strong stirring and precipitated to obtain a polymer, and the weight average molecular weight of the prepared polymer was 8.9 × 10 ⁴ g/mol. A schematic diagram of free radical polymerization of the prepared polymer (hereinafter referred to as P73) is shown in FIG. 1 .

After dissolving the recovered polymer (P73) in an ethanol/water mixed solvent (7:3 volume ratio), AgBF ₄ as a silver salt and [bmim][BF ₄ ] as an ionic liquid (IL) were added to The mixture was prepared by stirring for two hours. At this time, the polymer (P73), AgBF ₄ and [bmim][BF ₄ ] were mixed at a weight ratio of 1:3:0.3, and the solid content of the composite was 10% by weight.

The prepared composite was applied to the surface of a polysulfone porous substrate coated with poly[1-(trimethylsilyl)-1-propane] (PTMSP) using an RK coater, and in a vacuum oven at 25 °C for 24 hours. After completely drying, a gas separation membrane having an acrylic selective layer having a thickness of 800 nm was prepared.

[Example 2]

In Example 1, a polymer (hereinafter referred to as P55) prepared using 5 g of 2-hydroxypropyl-2-(methacryloyloxy)ethyl phthalate (HMEP) and 5 g of acrylic acid (AA) was used. Except for that, it was carried out in the same manner as in Example 1.

[Example 3]

In Example 1, a polymer (hereinafter referred to as P37) prepared using 3 g of 2-hydroxypropyl-2-(methacryloyloxy)ethyl phthalate (HMEP) and 7 g of acrylic acid (AA) was used. Except for that, it was carried out in the same manner as in Example 1.

[Example 4]

A composite prepared using the polymer, AgBF ₄ and [bmim][BF ₄ ] in a weight ratio of 1: 4: 0.4 in Example 1, and carried out in the same manner as in Example 1 except for forming an acrylic selective layer. Thus, a gas separation membrane was prepared.

[Example 5]

In Example 1, the polymer, AgBF ₄ and [bmim][BF ₄ ] is a composite prepared using a weight ratio of 1: 5: 0.5, and the same procedure as in Example 1 was performed except for forming an acrylic selective layer. Thus, a gas separation membrane was prepared.

[Comparative Example 1]

A gas separation membrane was prepared in the same manner as in Example 1, except that the composite was prepared without using [bmim][BF ₄ ] in Example 1 to form an acrylic selective layer.

[Comparative Example 2]

In Example 1, a gas separation membrane was prepared in the same manner as in Example 1, except that the composite was prepared without using AgBF ₄ to form an acrylic selective layer.

[Comparative Example 3]

In Example 1, a gas separation membrane was prepared in the same manner as in Example 1, except that a composite was prepared without using AgBF ₄ and [bmim][BF ₄ ] to form an acrylic selective layer. .

[Experimental Example 1] Crystallinity and structure analysis of copolymer

The structure and crystallinity of the polymers prepared in Examples 1 to 3 were determined by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy ( ¹ H-NMR), XRD (X-ray diffraction) and differential scanning calorimeter (DSC), and the results are shown in FIGS. 2(a) to 2(d), respectively.

As shown in FIG. 2 (a), in the FT-IR spectra of the polymers prepared in Examples 1 to 3, respectively, 2-hydroxypropyl-2- (methacryloyloxy) ethyl phthalate (HMEP) and acrylic acid ( It was confirmed that the C=C stretching vibration band at 1637 cm ^-1 observed in AA) completely disappeared, and strong absorption bands due to C=O stretching were confirmed in HMEP and AA at 1716 and 1696 cm ^-1 .

In addition, the synthesized copolymer showed a wide absorption band between 1650 and 1750 cm ^-1 due to the presence of C=O bonds in different functional groups, and phthalate (1272 cm ^-1 ) and carboxylic acid (1238 cm ^-1 ) A wide CO stretch band between 1200 and 1300 cm ^-1 originating from the ether group of was confirmed.

In addition, in FIG. 2 (b) showing ¹ H-NMR of the polymers prepared in Examples 1 to 3, it was confirmed that the signals at 6.0 and 5.6 ppm corresponding to C = C double bond protons were negligibly low, This means that no residual monomer remains. As shown in FIGS. 2 (a) and (b), it was confirmed that P73, P55, and P37, which are examples of the copolymer represented by Formula 1a of the present invention, were successfully synthesized.

As shown in FIG. 2(c), it was confirmed that the XRD patterns of the polymers prepared in Examples 1 to 3 did not have sharp crystalline peaks and had amorphous characteristics, and as the content of acrylic acid (AA) constituting the polymer increased, It was confirmed that the relative intensity of the peak gradually increased at 2θ = 19.2 °. In addition, as shown in FIG. 2 (d) showing the DSC thermogram, it can be seen that the glass transition temperature (Tg) of the copolymer increases as the content of HMEP decreases, and the copolymers prepared in Examples 1 to 3 It was found that all were in a glass transition temperature (Tg) value higher than room temperature. This minimizes the permeation of N ₂ , which is dominated by the diffusion transport mechanism, and can further improve the permeability of carbon monoxide (CO).

[Experimental Example 2] Cross-section and surface characteristics of gas separation membrane

The cross section and surface of the gas separation membrane prepared in Examples 1 to 3 and Comparative Example 3 and Comparative Example 1 were observed through a scanning electron microscope (SEM) and a transmission electron microscope (TEM), respectively. 3 and 4, respectively.

As shown in FIG. 3, it was found that the prepared gas separation membrane had a thickness of 0.8 μm and an acrylic selective layer without defects. In addition, as shown in FIG. 4, in the case of Example 1 using P73 having a high content of phthalate groups in the polymer, fewer Ag nanoparticles were observed than in Examples 2 and 3, indicating that 2-hydroxypropyl-2-( It is predicted that the phthalate group of methacryloyloxy)ethyl phthalate (HMEP) is attributable to inhibition of Ag ion reduction.

[Experimental Example 3] Structural analysis of gas separation membrane

Intermolecular interactions in the acrylic selective layer of the gas separation membrane prepared in Examples 1 to 3 were analyzed by Fourier transform infrared spectroscopy (FT-IR) spectroscopy and are shown in FIG. 5 . As shown in FIG. 5, the change in the C=O absorption band position of Comparative Example 3 without both AgBF ₄ and [bmim][BF ₄ ] and Example 6 without [bmim][BF ₄ ] was negligible (1715 cm ^-1 ), while the ether band shifted from 1272 cm ^-1 to a slightly higher wavenumber (1275 cm ^-1 ). This appears to be due to the weak interaction of the ionic liquid (IL) with the phthalate ester groups of the copolymer.

In Comparative Example 2, it can be seen that the free C=O band moves slightly from 1715 cm ^-1 to 1698 cm ^-1 by AgBF4, and C=O by C=O coordinated with silver. It was found that a band appeared at 1633 cm ^-1 . This red shift was predicted to be due to the weakening of the C=O band due to the sharing of an electron pair between the carbonyl oxygen and the silver ion. However, it can be seen that 1705 cm ⁻¹ moves further to a higher region, which is due to the introduction of [bmim][BF ₄ ], an ionic liquid (IL), and further interaction between the carbonyl group of the copolymer and the ionic liquid It is judged to be due to partially obstructing the interaction between carbonyl and silver ions. In addition, in the case of Example 1 including both AgBF ₄ and [bmim] [BF ₄ ], it was found that the central region of 1272 cm ⁻¹ , which is the CO band, moved to a higher region. This seems to be due to the coordination of silver ions to the ester group, providing a resonance structure that increases the CO bond strength.

[Experimental Example 4] Gas separation performance of gas separation membrane

The permeability and selectivity of the gas separation membranes prepared in Examples 1 to 3 and Comparative Examples 1 and 3 were measured in a mixed gas mixture of carbon monoxide and nitrogen at 25 ° C and 1 bar, and are shown in Table 1 below. showed up

gas separation membrane composite composition Permeability (GPU) Selectivity (CO/N ₂ ) CO N ₂ Example 1 P73+AgBF ₄ +[bmim][BF ₄ ] 2.3 0.5 4.6 Example 2 P55+AgBF ₄ +[bmim][BF ₄ ] 10.7 2.6 4.1 Example 3 P37+AgBF ₄ +[bmim][BF ₄ ] 8.2 3.7 2.2 Comparative Example 1 P73+ _AgBF4 7.5 5.7 1.3 Comparative Example 3 P73 defective

As shown in Table 1, in the case of Comparative Example 3, which is a gas separation membrane manufactured using only polymers, the separation membrane was very defective, and the CO/N ₂ selectivity was about 1 due to Knudsen diffusion, so the selectivity was very low. . However, in the case of Comparative Example 1 in which AgBF ₄ was mixed with a polymer, structural defects were prevented, and CO permeability of 7.5 GPU and CO/N ₂ selectivity were improved to 1.3, but still showed low physical properties in gas selectivity. This appears to have risen to some extent because of the densification of the polymer structure due to the temporary cross-linking of the membrane originating from the strong coordination interaction between Ag ions and C=O groups. In addition, in the case of the gas separation membranes of Examples 1 to 3 having all the configurations of the present invention, the CO/N ₂ selectivity increased from 2 or more to at least 2.2 or more, and in the case of Example 1, the selectivity increased to 4.6, which is very surprising. was found to have This means that transport of CO occurred easily through the gas separation membrane. In addition, the change in the composition of the copolymer matrix of the acrylic selective layer affects the separation performance, and as confirmed in FIG. 4, 2-hydroxypropyl-2-(methacryloyloxy)ethyl phthalate (HMEP) It can be seen that the phthalate group not only inhibits the reduction of Ag ions, but also increases the CO/N ₂ selectivity as the HMEP content of the copolymer increases.

In Examples 1, 4, and 5, the thickness of the acrylic selective layer was formed to be 2 μm, and the transmittance and selectivity were further measured at 25 ° C and 4 bar in a mixed gas mixture of carbon monoxide and nitrogen, It is shown in Table 2 below.

gas separation membrane P73 _: AgBF4 _: [bmim][BF4]
weight ratio Thickness of acrylic selective layer Permeability (GPU) Selectivity (CO/N ₂ ) CO N ₂ Example 1 1:3:0.3 2 μm 1.1 0.14 7.9 Example 4 1:4:0.4 2.1 0.13 16.2 Example 5 1:5:0.5 2.1 0.28 7.4

As in Table 2, in the case of Example 1, as the thickness of the selective layer was increased to 2 μm, unlike in Table 1 in which the gas separation performance was measured when the thickness of the selective layer was 800 nm, CO / It was found that the N ₂ selectivity increased. In addition, it was found that both CO permeability and CO/N ₂ selectivity improved as the content of AgBF ₄ increased. That is, it can be seen that CO transport by the gas separation membrane according to an embodiment of the present invention is successfully promoted.

As described above, the present invention has been described by specific details and limited embodiments and drawings, but this is only provided to help a more general understanding of the present invention, the present invention is not limited to the above embodiments, and the present invention Those skilled in the art can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all modifications equivalent or equivalent to the claims will be said to belong to the scope of the present invention.

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Claims (12)

porous substrates; and
Including; acrylic-based selection layer formed on the surface of the porous substrate,
The acryl-based selective layer is a gas separation membrane formed by coating a composite including a copolymer represented by Formula 1 below, a silver salt, and an ionic liquid.
[Formula 1]

(In Formula 1 above,
The R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ ,
The R _{2 and} R ₂ 'are the same as or different from each other, and are each independently a straight-chain or branched C2-C6 alkylene group,
Wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group,
Wherein x = a natural number from 1 to 300, y = a natural number from 1 to 600, and z = a natural number from 1 to 3.) delete According to claim 2,
The copolymer is a gas separation membrane obtained by reacting the compound represented by Chemical Formula 2 with the compound represented by Chemical Formula 3 at a weight ratio of 7:3 to 3:7.
[Formula 2]

(In Chemical Formula 2,
The R ₁ is each independently selected from hydrogen and -CH ₃ ,
The R _{2 and} R ₂ 'are the same as or different from each other, and are each independently a straight-chain or branched C2-C6 alkylene group,
Wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group,
The z = is a natural number from 1 to 3.)
[Formula 3]

(In Formula 3,
The R ₁ 'are independently hydrogen or -CH ₃ .) According to claim 2,
The ionic liquid is composed of an organic cation and an anion, and the cation is any one cation selected from dialkylimidazolium, alkylpyridinium, quaternary ammonium, and quaternary phosphonium, and the anion is NO Among ₃ ^- , BF ₄ ^- , PF ₆ ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , TfO-(Trifluoromethanesulfonate), Tf ₂ N-(Trifluoromethanesulfonylamide) and CH ₃ CH(OH)CO ₂ -(L-lactate) Any one of the anions selected, the gas separation membrane. According to claim 2,
The composite includes 200 to 500 parts by weight of a silver salt and 20 to 50 parts by weight of an ionic liquid, based on 100 parts by weight of the copolymer represented by Chemical Formula 1. According to claim 1,
The gas separation membrane, wherein an additional gutter layer is further formed on the surface of the porous substrate. According to claim 6,
The gas separation membrane wherein the gutter layer includes a siloxane-based polymer or a substituted polyacetylene. According to claim 1,
The thickness of the selective layer is 300 nm to 1,000 nm, the gas separation membrane. According to claim 1,
The gas separation membrane has a CO / N ₂ selectivity of 2.0 or more at 25 ° C. 1 bar. According to claim 1,
The gas separation membrane is a gas separation membrane for selectively separating carbon monoxide by facilitated transport. preparing a composite comprising a copolymer represented by Chemical Formula 1, a silver salt, and an ionic liquid; and
A method of manufacturing a gas separation membrane comprising the steps of coating and drying the composite on the surface of a porous substrate to form an acrylic selective layer.
[Formula 1]

(In Formula 1 above,
The R ₁ and R ₁ 'are the same as or different from each other and are each independently selected from hydrogen and -CH ₃ ,
The R _{2 and} R ₂ 'are the same as or different from each other, and are each independently a straight-chain or branched C2-C6 alkylene group,
Wherein R ₃ is each independently hydrogen or a C1-C3 alkyl group,
Wherein x = a natural number from 1 to 300, y = a natural number from 1 to 600, and z = a natural number from 1 to 3.) According to claim 11,
The method of manufacturing a gas separation membrane comprising the step of further forming an additional gutter layer on the surface of the porous substrate before the step of forming the acrylic selective layer.

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