CN113522064B - Preparation method of novel MOF-based hydrogel gas separation membrane - Google Patents
Preparation method of novel MOF-based hydrogel gas separation membrane Download PDFInfo
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- 238000000926 separation method Methods 0.000 title claims abstract description 87
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- 238000002360 preparation method Methods 0.000 title claims abstract description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000000463 material Substances 0.000 claims abstract description 40
- 238000000034 method Methods 0.000 claims abstract description 27
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- 239000002243 precursor Substances 0.000 claims abstract description 14
- 238000010526 radical polymerization reaction Methods 0.000 claims abstract description 3
- 239000007789 gas Substances 0.000 claims description 109
- 239000000243 solution Substances 0.000 claims description 19
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 18
- 238000006116 polymerization reaction Methods 0.000 claims description 16
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- 238000002156 mixing Methods 0.000 claims description 9
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- 238000005054 agglomeration Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/56—Polyamides, e.g. polyester-amides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
- B01D53/228—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0006—Organic membrane manufacture by chemical reactions
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/46—Polymerisation initiated by wave energy or particle radiation
- C08F2/48—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/151—Reduction of greenhouse gas [GHG] emissions, e.g. CO2
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Abstract
The invention discloses a preparation method of a novel MOF-based hydrogel gas separation membrane, which comprises the following steps: the metal-organic framework material with water stability is introduced into the hydrogel polymer precursor solution, and an ultraviolet light initiated free radical polymerization method is adopted to prepare the MOF-based hydrogel gas separation membrane with good carbon dioxide separation performance in one step. The membrane material prepared by the invention is self-supporting, and water is used as a solvent, so that on one hand, the compatibility of an MOF (metal organic framework) and a polymer matrix interface in the membrane material is improved, and the defect of no selection of the interface is eliminated; on the other hand, water has a promoting effect on CO 2 Is CO 2 More gas permeation and transmission channels are provided. The membrane material prepared by the invention has the advantages of green and environment-friendly raw materials, simple preparation method and mild conditions, is suitable for separating the water-stable MOF from various gas systems in different water environments, is suitable for industrial production, and provides a reference for expanding the application of the MOF-based mixed matrix hydrogel membrane in gas separation.
Description
Technical Field
The invention relates to the field of gas membrane separation, in particular to a preparation method of a novel MOF-based hydrogel gas separation membrane.
Background
The gas separation membrane technology has the advantages of environmental protection, low energy consumption, high efficiency, sustainability, small equipment floor area, high separation efficiency, simple and convenient operation and the like, and is widely applied to natural gas purification, hydrogen storage and carbon dioxide (CO) 2 ) The method has the advantages of showing wide application prospect, and providing technical support for promoting chemical energy conservation and emission reduction, efficiently and cleanly utilizing energy and realizing 'carbon peak reaching' and 'carbon neutralization'. As one of the typical representatives of many membrane materials, MOF-based Mixed matrix membranes (Metal-organic framework based Mixed matrix membranes) integrate polymer matrix processability and excellent separation properties of MOF materials, exhibiting high gas permeability and high selectivity. However, interfacial compatibility issues have long been an important factor limiting their performance for optimal gas separation. The primary consideration for achieving high separation performance is to ensure good interfacial bonding between the polymer and the MOF.
Aiming at the key problem, the methods mainly solved at present comprise modification and modification of MOF, interface layer design, development of composite MOF filler, an external interface agent adding method and the like. In contrast, the method of adding an interfacial agent is a simple and effective way, and the method has the greatest advantages that the polymer matrix and the MOF do not need to be modified, and the defect of no selectivity caused by the incompatibility of the interface is eliminated by virtue of good combination of the interfacial solvent and the polymer matrix and the MOF. Most of the commonly used interfacial solvents are Ionic Liquids (ILs), long-chain macromolecules and the like, but the industrial expansion application is greatly limited due to higher economic cost, complicated synthesis conditions and higher purity requirements.
The invention adopts the conventional green solvent-water as an interfacial solvent, takes the MOF and the polymer hydrogel with water stability as the film material basis, and eliminates the film by the stable combination bridging effect of the water, the hydrogel and the hydrophilic MOFHas no selective interface defect, and simultaneously, water can be mixed with CO 2 Hydration and dissociation reactions occur, increasing CO 2 The mode of transmission in the membrane improves CO 2 In addition, the MOF is used as a filler to enhance the mechanical property of the polymer hydrogel membrane, the prepared membrane is self-supporting, and further industrial application of the hydrogel membrane in the field of gas separation is expanded.
Disclosure of Invention
The invention combines water-stable MOF with polyacrylic acid hydrogel films to prepare a novel MOF-based hydrogel gas separation film, and optimizes and controls the separation performance of the film materials by adjusting the water content of a polymerization precursor, the MOF content, the MOF type and other factors. The membrane material prepared by the method has good CO 2 The separation performance and the application prospect are good.
The technical problem to be solved by the invention is as follows: the invention uses the conventional green solvent water as the interface solvent, selects MOF and polymer materials matched with the interface solvent, eliminates the defect of no selectivity in the membrane material, and increases CO simultaneously 2 The mode of transmission in the membrane improves CO 2 In addition, the MOF is used as a filler to enhance the mechanical property of the polymer hydrogel membrane, so that the self-supporting hydrogel gas separation membrane is prepared, and further industrial application of the hydrogel membrane in the field of gas separation is expanded.
The technical scheme of the invention is as follows: a method of making a novel MOF-based hydrogel gas separation membrane, the method comprising the steps of:
(1) preparation of a polymerization precursor solution: adding a polymerized monomer and a cross-linking agent into water at room temperature, adjusting the pH of the solution to be neutral, then adding MOF and a photoinitiator into the mixed solution, and uniformly mixing for later use;
(2) preparation of membrane material: and (2) uniformly coating the polymerization precursor solution prepared in the step (1) on quartz glass by adopting an ultraviolet light initiated free radical polymerization method, and obtaining the MOF-based hydrogel gas separation membrane under the ultraviolet light illumination condition, wherein the membrane can be directly used for gas separation.
In the step (1), the selected MOF has good water stability and hydrophilicity, the composition and the crystal structure of the MOF are kept in a water environment, and the average contact angle is 10-60 degrees.
In the step (1), the selected MOF can be a multi-dimensional structure, wherein the thickness of the two-dimensional MOF is 2-10nm, and the particle size of the three-dimensional MOF structure is 100-500 nm.
In the step (1), the material ratio of the mixed homogeneous phase solution of the MOF/the polymer monomer/the cross-linking agent/the initiator/water is as follows:
MOF, polymer monomer, cross-linking agent, initiator and water, wherein the amount of the cross-linking agent is 0.03-1.30g, the amount of the cross-linking agent is 3g, the amount of the cross-linking agent is 0.01-0.03g, and the amount of the cross-linking agent is 4-25 mL;
adjusting the pH of the polymerization environment by using sodium hydroxide or potassium hydroxide;
MOF content was characterized using mass fraction.
Wherein, the polymer monomer adopted in the polymerization precursor in the step (2) is acrylic acid, and comprises the following components: acrylic acid, acrylamide, methacrylic acid and N-isopropyl acrylamide, wherein the cross-linking agent is N, N' -methylene bisacrylamide, and the photoinitiator is Irgacure 2959.
Wherein, the wavelength of the ultraviolet light in the step (2) is 312nm, and the polymerization time is 10-60 min.
Wherein, the preparation process of the film material in the step (2) is carried out at room temperature, and no organic solvent is added.
The MOF-based hydrogel gas separation membrane prepared by the method can be directly used for gas separation after preparation, and no post-treatment is needed.
The MOF-based hydrogel gas separation membrane prepared by the method is used for different gas components and comprises the following steps: CO2 2 /CH 4 、CO 2 /H 4 、CO 2 /N 2 And (5) separating.
The MOF-based hydrogel gas separation membrane prepared by the method is suitable for gases in different water environments.
The invention has the advantages that: (1) the invention uses water as an interfacial solvent, solves the defect of no selectivity caused by MOF/polymer compatibility, and simultaneously increases CO 2 The mode of transmission in the film improves the CO content of the hydrogel film 2 Separation performance; (2) the film material of the inventionThe preparation method is simple, green and environment-friendly, the synthesis condition is mild, the economic cost of raw materials is low, and the prepared membrane belongs to a self-supporting membrane and is suitable for industrial production; (3) the invention is suitable for the MOF with water stability, different gas components and gases in different water environments.
At present, most of interfacial agents adopted in the market are ionic liquid and some long-chain polymers; however, they are of a wide variety, and various synthetic methods, yield, product purity, synthetic steps and post-treatments, etc. limit large-scale applications.
The invention mainly compares from two aspects: (1) in contrast, compared with other gel membranes (containing ionic liquid and partial hydrogel composite membranes), the introduction of the water-stable type a520 allows the membrane material to exhibit a synchronous increase in flux and selectivity; at the same time, separation selectivity can be improved without sacrificing gas flux, for example, a gel membrane with flux greater than 500Barrer, selectivity is usually lower than 20, while a gel membrane sample with selectivity higher than 50, has lower flux, generally lower than 300 Barrer; (2) in terms of economic cost and film making process, the invention has another starting point that the economic cost (including the cost of materials and the cost of preparation process) is considered, the cost is reduced and the environment is protected by adopting water as the interfacial agent on the premise of ensuring the compatibility, the working film material is economic and low, belongs to a self-supporting film and has no substrate limitation, and the one-step method ultraviolet light film making process has mild conditions and is simple and rapid.
The innovation of the invention comprises the following points: (1) the water-stable MOF material is compounded with hydrogel to prepare the MOF-based hydrogel membrane for CO2 separation, the prepared membrane can be suitable for various separation environments (dry gas, wet gas and cyclic utilization), and related reports on the application of the MOF-based hydrogel membrane in the direction are less; (2) water is used as an interface agent instead of expensive ionic liquid, and is used for adjusting the interface compatibility of a mixed matrix membrane, improving the MOF dispersion problem and reducing the material cost on the premise of ensuring the separation performance; is CO 2 The design of the separation membrane provides a new direction and has stronger practicability; (3) as a self-supporting membrane, the membrane does not need expensive substrate material, and provides an economic and environment-friendly membrane separation material for developmentReference is made to.
Drawings
FIG. 1: a520 preparing a flow chart of the hydrogel gas separation membrane.
FIG. 2: scanning electron microscope image of A520 hydrogel gas separation membrane.
FIG. 3: a520 hydrogel gas separation membrane fluorescence microscopy.
FIG. 4: a520 hydrogel gas separation membrane pair CO 2 /CH 4 Gas system CO 2 Schematic isolation.
FIG. 5: CO of A520 hydrogel gas separation membrane with same polymeric precursor water content and different A520 contents under dry gas condition 2 /CH 4 Mixed gas separation performance diagram.
FIG. 6: CO of A520 hydrogel gas separation membrane with same polymeric precursor water content and different A520 contents under wet gas condition 2 /CH 4 Mixed gas separation performance diagram.
FIG. 7: CO of A520 hydrogel gas separation membrane with same A520 content and different polymerization precursor water content under dry gas condition 2 /CH 4 Mixed gas separation performance diagram.
FIG. 8: CO for 6 reuses of A520 hydrogel gas separation membranes under dry gas conditions 2 /CH 4 Mixed gas separation performance diagram.
FIG. 9: CO of ZIF-8 hydrogel gas separation membrane with same polymeric precursor water content and different ZIF-8 contents under dry gas condition 2 /CH 4 Mixed gas separation performance diagram.
Detailed Description
The model and manufacturer information of the equipment used in each example is as follows:
reference to the membrane material CO used in the examples 2 The permeation rate, selectivity, of (c) was tested as follows:
at normal temperature and under 0.2Mpa, the prepared self-supporting material is processedAnd placing the supported MOF-based hydrogel gas separation membrane in a self-made metal membrane pool for gas performance test. The effective area of the membrane was 0.785cm 2 The method is characterized in that a double-component mixed gas (the volume ratio is 1: 1) is adopted as a feed gas, helium is adopted as a purge gas, the gas at the permeation side is brought into a gas chromatograph by the purge gas for analysis, and in a moisture gas test, the feed gas and the purge gas need to enter a humidifier before entering a membrane pool. Methods for measuring permeation rate and selectivity, references (X.Jia, Z Qiao, B He, C.Zhong, high Selective Filler-polymer Gaps in Situ Fabricated textile in Mixed Matrix Membranes for Gas Separation, J.Mater.chem.A.8(2020)11928-
Examples 1 to 6: preparation of A520 hydrogel gas separation membrane with same polymeric precursor water content and different MOF content
(1) Preparation of A520
At room temperature, dissolving 7g of aluminum sulfate octadecahydrate in 30mL of water in a glass reactor, and heating the mixed solution to 60 ℃; weighing fumaric acid (2.43g) and sodium hydroxide (2.52g) and dissolving in 36mL of water, heating to 60 ℃, slowly adding into an aqueous solution of aluminum sulfate dropwise, centrifuging the formed white suspension at 9000rpm, washing with water for 3 times, and vacuum drying at 100 ℃ for 24h to obtain A520 white powder;
(2) preparation of polymeric precursor solution
Weighing 2g of acrylic acid, 1g of acrylamide and 0.02g of N, N' -methylene bisacrylamide at room temperature, adding the weighed materials into 10mL of water, uniformly mixing, adding 1.11g of sodium hydroxide to adjust the pH value of the solution to be neutral, then adding a certain amount of A520 (the amount of A520 is shown in the following table) and 0.015g of photoinitiator Irgacure2959 into a reactor, and uniformly mixing for later use;
(3) preparation of Membrane Material
Uniformly coating the prepared polymerization precursor solution on quartz glass, and illuminating for 30min under the condition that the ultraviolet wavelength is 312nm to obtain an A520 hydrogel gas separation membrane;
FIG. 1: a520, preparing a hydrogel gas separation membrane, wherein the method is a one-step membrane preparation method, and the prepared membrane material can be directly used for gas separation without post-treatment;
FIG. 2: a520 hydrogel gas separation membrane scanning electron microscope picture, the membrane material keeps the three-dimensional porous structure of the hydrogel material, the A520 particles are clearly visible in the further amplification observation of the pore wall, and the monomer polymerization process is not changed by the introduction of A520;
FIG. 3: a520 hydrogel gas separation membrane fluorescence microscopy picture, the dyed A520 is uniformly dispersed in the water core of the hydrogel membrane, but not completely fixed in the polymer matrix; such a structure not only eliminates the interfacial incompatibility of the hydrogel and A520 through water, but also provides more CO 2 A permeation pathway within the membrane comprising: nanochannel, water and CO formed by A520 material structure 2 Hydration and dissociation;
FIG. 4: a520 hydrogel gas separation membrane pair CO 2 /CH 4 Gas system CO 2 Schematic isolation.
FIG. 5: CO of A520 hydrogel gas separation membrane with same polymeric precursor water content and different A520 contents under dry gas condition 2 /CH 4 A mixed gas separation performance diagram; a520 MMHMs CO with increasing A520 content 2 Permeation rate, CO 2 /CH 4 The selectivity of (A) is gradually increased and then slightly decreased to be smooth, which is caused by that A520 has certain CO 2 Separation Performance, with increasing content, CO 2 /CH 4 The more obvious the separation is, but the high content can cause the agglomeration of A520 to be unfavorable for the separation and the film forming;
FIG. 6: CO of A520 hydrogel gas separation membrane with same polymeric precursor water content and different A520 contents under wet gas condition 2 /CH 4 A mixed gas separation performance diagram; the trend is basically consistent with the dry gas state, the permeation rate and the selectivity are not reduced sharply, and because A520 contains hydroxyl and other functional groups which form hydrogen bonds with water, the water environment in the membrane material is not influenced greatly by water vapor in the gas permeation process under the wet gas condition.
Examples 7 to 11: preparation of A520 hydrogel gas separation membrane with same load and different polymer precursor water contents
(1) Preparation of a520 the same as in example step (1);
(2) preparation of polymeric precursor solution
Weighing 2g of acrylic acid, 1g of acrylamide and 0.02g of N, N' -methylene bisacrylamide at room temperature, adding a certain amount of water (the amount of water is shown in the table), uniformly mixing, adding 1.11g of sodium hydroxide to adjust the pH of the solution to be neutral, then adding 0.3985g A520 (the content of A520 is 11.6%) and 0.015g of photoinitiator Irgacure2959 into a reactor, and uniformly mixing for later use;
(3) preparation of Membrane Material As in example step (3)
FIG. 7: CO of A520 hydrogel gas separation membrane with same A520 content and different polymerization precursor water content under dry gas condition 2 /CH 4 A mixed gas separation performance diagram; CO with increasing water content 2 Increased permeation rate of, CO 2 /CH 4 With gradually decreasing selectivity of CO 2 The hydration and dissociation processes increase with increasing water content, but excessive water content causes excessive crosslinking of the hydrogel material, limiting gas selectivity;
example 12: preparation and reuse conditions of A520 hydrogel gas separation membrane with MOF content of 16.24%
(1) Preparation of a520 the same as in example step (1);
(2) preparation of polymeric precursor solution
Wherein, the content of A520 is 16.24%;
(3) preparation of Membrane Material As in example step (3)
FIG. 8 is a 6-fold repetition of an A520 hydrogel gas separation membrane having an A520 content of 16.24% under dry gas conditionsCO used 2 /CH 4 A mixed gas separation performance diagram; because A520 and hydrogel polymer chains can form hydrogen bonds with water, the membrane still keeps CO after 6 times of recycling 2 Penetration rate of 390Barrer, CO 2 /CH 4 The selectivity of (a) was 45.
Examples 12 to 15: preparation of ZIF-8 hydrogel gas separation membrane with same polymeric precursor water content and different MOF content
(1) Preparing ZIF-8;
weighing 9.939g of zinc hydroxide and 39.408g of 2-methylimidazole, putting the zinc hydroxide and the 2-methylimidazole into a mortar, manually grinding the mixture for 5min at room temperature, putting the mixture into a ball mill for grinding, controlling the rotating speed to be 450r/min, carrying out ball milling for 120min, cleaning the obtained white powder with methanol for three times, centrifuging the powder at 9800rpm, and carrying out vacuum drying at 100 ℃ to obtain ZIF-8 powder;
(2) preparation of polymeric precursor solution
Weighing 2g of acrylic acid, 1g of acrylamide and 0.02g of N, N' -methylene bisacrylamide at room temperature, adding the weighed materials into 10mL of water, uniformly mixing, adding 1.11g of sodium hydroxide to adjust the pH value of the solution to be neutral, then adding a certain amount of ZIF-8 (the amount of the ZIF-8 is shown in the following table) and 0.015g of photoinitiator Irgacure2959 into a reactor, and uniformly mixing for later use;
(3) the preparation of the membrane material is the same as the step (3) of the example;
FIG. 9 is a graph of CO for ZIF-8 hydrogel gas separation membranes of the same polymeric precursor water content and different ZIF-8 contents under dry gas conditions 2 /CH 4 A mixed gas separation performance diagram; CO with increasing ZIF-8 content 2 Permeation rate, CO 2 /CH 4 The selectivity of the ZIF-8 is increased firstly and then decreased, and is different from the A520 two-dimensional structure, and the ZIF-8 arrangement mode of the three-dimensional structure ensures that the separation effect of a gas transmission channel formed by ZIF-8 is obviously reduced along with the increase of the content;
example 16: preparation of ZIF-L hydrogel gas separation membrane with content of 4.77%
(1) Preparing ZIF-L;
dissolving 2.9749g of zinc nitrate hexahydrate in 40mL of deionized water in a glass reactor at room temperature, stirring and adding a mixed solution in which 5.74g and 40mL of deionized water are dissolved, stirring and dissolving for 4h at room temperature, centrifuging the formed white suspension at 9500rpm, washing for 3 times by using anhydrous methanol, and performing vacuum drying at 100 ℃ for 24h to obtain ZIF-L white powder;
(2) preparation of polymerization precursor solution one step (2) of the same example
Wherein, the content of ZIF-L is 4.77%;
(5) the preparation of the membrane material is the same as the step (3) of the embodiment;
the gas test shows that the content of CO of 4.77 percent ZIF-L MMHM under the conditions of room temperature and dry gas 2 /CH 4 Gas separation Performance test under Mixed gas conditions, CO 2 147.94Barrer, CO 2 /CH 4 The selectivity of (a) is 55.62.
Example 17: preparation of UTSA 280 hydrogel gas separation membrane with content of 15.34%
(1) Preparing UTSA 280;
weighing 1.48 g of calcium hydroxide and 2.281g of squaric acid, mixing in an agate mortar, manually grinding for 5min at room temperature, putting the mixture in a ball mill, grinding for 120min, washing the synthesized powder for 3 times by using an ethanol solution, and drying in vacuum at 100 ℃ for 12h to obtain UTSA 280 white powder;
(3) preparation of precursor solution of Membrane Material in one step (2) of the same example
Wherein, the UTSA 280 content is 15.34%;
(5) preparation of UTSA 280MMHM membrane the same procedure as in example (1);
the gas test shows that the content of CO of UTSA 280MMHM is 15.34 percent under the conditions of room temperature and dry gas 2 /CH 4 Gas separation Performance test under Mixed gas conditions, CO 2 173.1Barrer, CO 2 /CH 4 The selectivity of (a) was 54.78.
Claims (6)
1. A preparation method of a novel MOF-based hydrogel gas separation membrane is characterized by comprising the following steps: the method comprises the following steps:
(1) preparation of a polymerization precursor solution: adding a polymerized monomer and a cross-linking agent into water at room temperature, adjusting the pH of the solution to be neutral, then adding MOF and a photoinitiator into the mixed solution, and uniformly mixing for later use; wherein the added MOF is A520 MOF;
(2) preparation of membrane material: uniformly coating the polymerization precursor solution prepared in the step (1) on quartz glass by adopting an ultraviolet light initiated free radical polymerization method, and obtaining the MOF-based hydrogel gas separation membrane under the condition of ultraviolet light illumination, wherein the membrane can be directly used for gas separation;
in the step (1), the thickness of the selected MOF is 2-10 nm;
a MOF-based hydrogel gas separation membrane prepared for different gas components comprising: CO2 2 /H 2 、CO 2 /CH 4 、CO 2 /N 2 Separating;
the polymer monomer adopted in the polymerization precursor in the step (1) is acrylic acid, and comprises the following components: acrylic acid, acrylamide, methacrylic acid and N-isopropyl acrylamide, wherein the cross-linking agent is N, N' -methylene bisacrylamide, and the photoinitiator is Irgacure 2959.
2. The method of preparing a novel MOF-based hydrogel gas separation membrane according to claim 1, wherein: in the step (1), the selected MOF has good water stability and hydrophilicity, and the average contact angle is 10-60 o 。
3. The method of preparing a novel MOF-based hydrogel gas separation membrane according to claim 1, wherein: in the step (1), the material proportion of the mixed homogeneous phase solution of MOF/polymer monomer/cross-linking agent/initiator/water is as follows:
MOF polymer monomer, cross-linking agent, initiator and water
0.03-1.30g, 3g, 0.01-0.03g, 4-25 mL; adjusting the pH of the polymerization environment by using sodium hydroxide or potassium hydroxide; MOF content was characterized using mass fraction.
4. The method of making a novel MOF-based hydrogel gas separation membrane according to claim 1, wherein: in the step (2), the wavelength of the ultraviolet light is 312nm, and the polymerization time is 10-60 min.
5. The method of preparing a novel MOF-based hydrogel gas separation membrane according to claim 1, wherein: the preparation process of the film material in the step (2) is carried out at room temperature, and no organic solvent is added.
6. The method of preparing a novel MOF-based hydrogel gas separation membrane according to claim 1, wherein: the prepared MOF-based hydrogel gas separation membrane is suitable for gases in different water environments.
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