CN117018887A - Preparation method and application of in-situ post-oxidized carbon molecular sieve hollow fiber membrane - Google Patents
Preparation method and application of in-situ post-oxidized carbon molecular sieve hollow fiber membrane Download PDFInfo
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- 239000012528 membrane Substances 0.000 title claims abstract description 131
- 239000012510 hollow fiber Substances 0.000 title claims abstract description 100
- 239000002808 molecular sieve Substances 0.000 title claims abstract description 53
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 title claims abstract description 53
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 47
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 45
- 238000011065 in-situ storage Methods 0.000 title claims abstract description 41
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- 238000011282 treatment Methods 0.000 claims abstract description 29
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 27
- 238000000926 separation method Methods 0.000 claims abstract description 17
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000001301 oxygen Substances 0.000 claims abstract description 10
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 10
- 230000001590 oxidative effect Effects 0.000 claims abstract description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 24
- 238000009987 spinning Methods 0.000 claims description 19
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 18
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 10
- 239000001569 carbon dioxide Substances 0.000 claims description 10
- 229920000168 Microcrystalline cellulose Polymers 0.000 claims description 9
- 235000019813 microcrystalline cellulose Nutrition 0.000 claims description 9
- 239000008108 microcrystalline cellulose Substances 0.000 claims description 9
- 229940016286 microcrystalline cellulose Drugs 0.000 claims description 9
- ZXLOSLWIGFGPIU-UHFFFAOYSA-N 1-ethyl-3-methyl-1,2-dihydroimidazol-1-ium;acetate Chemical compound CC(O)=O.CCN1CN(C)C=C1 ZXLOSLWIGFGPIU-UHFFFAOYSA-N 0.000 claims description 8
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 8
- 238000003763 carbonization Methods 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 5
- 229910002090 carbon oxide Inorganic materials 0.000 claims description 4
- 238000010000 carbonizing Methods 0.000 claims description 3
- 238000001891 gel spinning Methods 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 claims description 3
- 239000007789 gas Substances 0.000 abstract description 23
- 230000003647 oxidation Effects 0.000 abstract description 11
- 230000035699 permeability Effects 0.000 abstract description 11
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 5
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- 229910021641 deionized water Inorganic materials 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
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- 229910052786 argon Inorganic materials 0.000 description 2
- 230000001112 coagulating effect Effects 0.000 description 2
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
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- 235000007034 Carum copticum Nutrition 0.000 description 1
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Classifications
-
- 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
- B01D71/02—Inorganic material
- B01D71/021—Carbon
-
- 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
-
- 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
- B01D67/0039—Inorganic membrane manufacture
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/08—Hollow fibre membranes
-
- 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
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/40—Capture or disposal of greenhouse gases of CO2
Abstract
The invention relates to a preparation method and application of an in-situ post-oxidized carbon molecular sieve hollow fiber membrane, wherein the preparation method comprises the following steps: and in an oxidizing atmosphere, applying a forward pressure difference between the shell side and the hollow tube side of the carbon molecular sieve hollow fiber membrane, and performing heating treatment to obtain the carbon molecular sieve hollow fiber membrane subjected to in-situ post-oxidation treatment. Compared with the prior art, the invention provides an in-situ oxidation strategy, which improves the separation performance of the CMS hollow fiber membrane by forcing oxygen to diffuse through the CMS hollow fiber membrane layer, performing oxygen doping and oxidation functionalization on the CMS hollow fiber membrane, customizing a gas transmission channel penetrating through a sub-nanometer size in the Emi size, and customizing and naturing the structure of the CMS hollow fiber membraneBeing able to optimize provides a simple strategy. After 60min of in-situ oxidation, CO 2 The permeability increased from 297.1Barrer to 1369.0Barrer, whereas CO 2 /N 2 Selectivity is kept at 51, CO 2 /CH 4 The selectivity remains at 101.
Description
Technical Field
The invention belongs to the technical field of gas separation membranes, relates to a preparation method and application of a carbon molecular sieve hollow fiber membrane, and particularly relates to a method for preparing a carbon molecular sieve hollow fiber membrane by using a catalystIn-situ post-oxidation treatment for realizing high-efficiency CO 2 A preparation method and application of a separated carbon molecular sieve hollow fiber membrane.
Background
For a long time, efficient CO development 2 Capturing techniques, e.g. separating CO from flue gas 2 And CO removal from natural gas 2 (cleaner substitute for coal or petroleum), reduction of CO 2 Emissions are attractive worldwide. Compared with the traditional heat driven separation technology, the membrane separation method has the advantages that the energy efficiency is improved exponentially, and the separation energy cost can be reduced. Among the various available membrane materials ranging from flexible polymers to rigid molecular sieve inorganic materials, carbon Molecular Sieve (CMS) membranes with excellent separation properties, chemical stability and ease of expansibility are CO 2 Separating one of the most attractive materials.
The CMS membrane is an inorganic molecular sieve membrane obtained by pyrolysis of a polymer precursor membrane, thereby combining the advantages of the polymer membrane and the inorganic membrane. In addition, CMS membranes have microporesAnd ultramicropore->The bimodal pore size distribution of (2) provides good gas permeability and molecular sieve properties. The pore structure characteristics of this dominant gas separation property can be tailored by different methods, including modification of the polymer precursor, control of carbonization conditions, and the use of additional post-treatments. The appropriate pore size is expected to achieve permeation to gas molecules, whereby the gas permeability of the CMS membrane can be further improved.
Currently, CMS membranes are used for CO 2 Is high in separation and capture efficiency, but CO is still present 2 Poor permeability and poor adsorption effect.
Disclosure of Invention
The invention aims to provide a high CO 2 A preparation method and application of a carbon molecular sieve hollow fiber membrane with selective permeability.
The aim of the invention can be achieved by the following technical scheme:
a preparation method of an in-situ post-oxidized carbon molecular sieve hollow fiber membrane comprises the following steps:
and in an oxidizing atmosphere, applying a forward pressure difference between the shell side and the hollow tube side of the carbon molecular sieve hollow fiber membrane, and performing heating treatment to obtain the carbon molecular sieve hollow fiber membrane subjected to in-situ post-oxidation treatment.
Further, the oxidizing atmosphere is an air atmosphere or an oxygen atmosphere.
Further, the forward pressure difference is 1-5 bar.
Further, the air pressure of the shell side of the carbon molecular sieve hollow fiber membrane is 2-6 bar, and the air pressure of the hollow tube side of the carbon molecular sieve hollow fiber membrane is 0.8-1.2 bar.
Further, in the heating treatment, the heating temperature is 280 to 330 ℃.
Further, the preparation method of the carbon molecular sieve hollow fiber membrane comprises the following steps:
s1: mixing microcrystalline cellulose (MCC), 1-ethyl-3-methylimidazole acetate (Emimac) and dimethyl sulfoxide (DMSO) to obtain spinning solution; preparing a spinning solution into a hollow fiber membrane by a dry-wet spinning method;
s2: and heating and carbonizing the hollow fiber membrane to obtain the carbon molecular sieve hollow fiber membrane.
Further, in the step S1, the content of microcrystalline cellulose in the spinning solution is 10-14 wt%; the mass ratio of the 1-ethyl-3-methylimidazole acetate to the dimethyl sulfoxide is 1 (2-4).
Further, in the step S2, the carbonization temperature is 550-650 ℃, and the carbonization time is 6-8 hours.
The in-situ post-oxidized carbon molecular sieve hollow fiber membrane is prepared by the method.
Use of an in situ carbon dioxide molecular sieve hollow fiber membrane as described above, comprising using said in situ carbon dioxide molecular sieve hollow fiber membrane for the separation of carbon dioxide from nitrogen and/or carbon dioxide from methane.
For the purpose ofImproving CO of the existing CMS hollow fiber membrane 2 The invention aims at modifying the structure of CMS hollow fiber membrane, proposes to utilize an in-situ air post-oxidation treatment method to enable air to permeate through the CMS hollow fiber membrane under the action of pressure difference, and adjust the structure and surface property of the CMS hollow fiber membrane by changing treatment time so as to realize in-situ regulation and control of the CMS hollow fiber membrane, thereby improving CO 2 Is used for the separation performance of the (c). The invention gradually increases the effective separation aperture of the CMS hollow fiber membrane by an in-situ post-oxidation treatment method, thereby enhancing CO 2 Is used for the permeability of the polymer. At the same time, due to post-oxidation treatment introducing CO 2 Oxygen-containing functional groups with high affinity further enhance CO 2 Is a solvent permeation selectivity of (a). Finally can realize the CO 2 Provides an engineering preference strategy for regulating and controlling the gas transmission channel of the CMS hollow fiber membrane in the Emi level.
Compared with the prior art, the invention has the following characteristics:
the invention provides an in-situ oxidation strategy, which is characterized in that oxygen doping and oxidation functionalization are carried out on the CMS hollow fiber membrane by forcing oxygen to diffuse through the CMS hollow fiber membrane layer, a gas transmission channel penetrating through a sub-nanometer size is customized in the Emi size, so that the separation performance of the CMS hollow fiber membrane is improved, and a simple strategy is provided for structural customization and performance optimization of the CMS hollow fiber membrane. After 60min of in-situ oxidation, CO 2 The permeability increased from 297.1Barrer to 1369.0Barrer, whereas CO 2 /N 2 Selectivity is kept at 51, CO 2 /CH 4 The selectivity remains at 101.
Drawings
FIG. 1 is an SEM image of a CMS hollow fiber membrane of example 1;
FIG. 2 is a graph showing changes in the interlayer spacing of CMS hollow fiber membranes in examples 1 to 3;
FIG. 3 is a graph showing pore diameter change of CMS hollow fiber membranes in examples 1 to 3;
FIG. 4 is a C1s chart of X-ray photoelectron spectroscopy (XPS) analysis of CMS hollow fiber membranes in examples 1-3;
FIG. 5 is an O1s graph of X-ray photoelectron spectroscopy (XPS) of the CMS hollow fiber membrane of examples 1 to 3;
FIG. 6 is a carbon dioxide adsorption isotherm (298K) of the CMS hollow fiber membranes of examples 1 to 3;
FIG. 7 is a schematic view of the structure of a membrane module;
fig. 8 is a partial enlarged view of the hollow fiber membrane at a in fig. 7.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples.
The preparation method of the in-situ post-oxidized carbon molecular sieve hollow fiber membrane comprises the following steps:
1) Taking microcrystalline cellulose as a raw material, and taking 1-ethyl-3-methylimidazole acetate and dimethyl sulfoxide as cosolvent to prepare spinning solution; preparing a spinning solution into a hollow fiber membrane by a dry-wet spinning method;
the content of microcrystalline cellulose in the spinning solution is 10-14 wt%; the 1-ethyl-3-methylimidazole acetate is used for dissolving cellulose, the dimethyl sulfoxide is used for reducing the solution viscosity, and the mass ratio of the 1-ethyl-3-methylimidazole acetate to the dimethyl sulfoxide is 1 (2-4); and preferably, the preparation temperature of the spinning solution is 55-65 ℃;
preferably, the hollow fiber membranes are collected in a deionized water tank and deionized water is replaced several times to completely remove the residual co-solvent;
2) Heating and carbonizing the hollow fiber membrane in an inert gas atmosphere at 550-650 ℃ for 6-8 hours to obtain a carbon molecular sieve hollow fiber membrane;
wherein the inert gas is argon or nitrogen; preferably, natural drying is carried out before heating and carbonization, the drying temperature is room temperature, and the drying time is 22-26 hours;
3) Applying a positive pressure difference of 1-5 bar between the shell side and the hollow tube side of the carbon molecular sieve hollow fiber membrane in an oxidizing atmosphere, and performing heating treatment at 280-330 ℃ for 0.5-1.5 h to obtain an in-situ post-oxidation treatment carbon molecular sieve hollow fiber membrane;
wherein the oxidizing atmosphere is preferably an air atmosphere or an oxygen atmosphere; preferably, the air pressure on the shell side of the carbon molecular sieve hollow fiber membrane is 2-6 bar, and the air pressure on the hollow tube side of the carbon molecular sieve hollow fiber membrane is 0.8-1.2 bar.
The application of the in-situ carbon oxide molecular sieve hollow fiber membrane comprises the step of using the in-situ carbon oxide molecular sieve hollow fiber membrane for separating carbon dioxide from nitrogen and/or carbon dioxide from methane.
Introducing compressed air into the membrane module, performing in-situ post-oxidation treatment by means of pressure difference and heating temperature, and increasing pore size and pore volume of CMS membrane by changing treatment time, enlarging Ammi level permeation micropores, and improving CO 2 Is a gas flux of (a). Meanwhile, the oxygen doping in the post-oxidation treatment can increase the content of oxygen-containing functional groups and improve the CO of the carbon molecular sieve hollow fiber membrane 2 Affinity of CO is further improved 2 Is effective in improving CO 2 Is used for the separation performance of the (c). The method provides a simple method for the structural modification of the carbon molecular sieve hollow fiber membrane, and has the advantages of easy realization of large-scale preparation and the like.
The following examples are given with the above technical solutions of the present invention as a premise, and detailed embodiments and specific operation procedures are given, but the scope of protection of the present invention is not limited to the following examples.
In the following examples, the spinning apparatus used was a model DKN-02 product of Seisakusho Lian Ke nm science and technology development, and the fiber film layer spacing was measured by an X-ray diffractometer (D8 Advance) and the pore size was measured by a specific surface area and porosity analyzer (BELSORP-MAX).
Example 1:
the preparation method of the carbon molecular sieve hollow fiber membrane CMS-0 comprises the following steps:
1) Preparing a hollow fiber membrane with cellulose as a precursor:
27.27g of MCC was added to 150g of DMSO in portions, stirred to disperse the MCC uniformly, and 50g of 1-ethyl-3-methylimidazole acetate was added to prepare a spinning solution. And (3) placing the spinning solution in a mixing instrument, setting the temperature to 60 ℃, and standing for 24 hours to fully and uniformly mix the solution. Placing the spinning solution at 60 ℃ into a spinning tankAfter cooling to normal temperature, the spinning solution and the core solution are respectively conveyed to a spinneret by using a spinning machine and a core solution pump, pass through a layer of air, and then enter a coagulating bath. The solvent is removed by normal temperature water elution and the membrane is solidified to prepare the hollow fiber membrane, wherein the core liquid is deionized water, the coagulating bath is water, and the temperature is room temperature. In the spinning process, the air gap between the spinneret and the coagulation bath was set to 2cm, and the spinning solution and core solution flow rates were respectively set to 3.5mL min -1 And 2.5mL min -1 . The winding speed of the hollow fiber membrane was maintained at 8m/min, the hollow fiber membrane was cut into 1.5m and collected in a deionized water tank, and deionized water was replaced several times to completely remove the residual co-solvent.
2) Preparation of CMS hollow fiber membranes:
the wet hollow fiber membrane was exposed to air for 24 hours and dried. Carbonization was performed in a tube furnace with argon purging at 600 ℃ for 6.5 hours to obtain a CMS hollow fiber membrane. In addition, SEM analysis was performed on the CMS hollow fiber membrane, and FIG. 1 is an SEM image of the surface and cross section of the CMS hollow fiber membrane, and it was found that the smooth membrane surface and the uniform membrane thickness were observed, and the membrane thickness was 28. Mu.m.
3) Preparation of a membrane module:
as shown in fig. 7, both ends of the CMS hollow fiber membrane are sealed in 2 tee joints 1, respectively, using a high temperature resistant epoxy resin glue 2, to make a membrane module so that gas can be introduced to the outside of the shell of the CMS hollow fiber membrane through the upper connection pipe of the tee joints 1, and gas can be introduced to the hollow pipe side of the CMS hollow fiber membrane through the outer ends of the 2 tee joints 1.
Gas separation Performance test
The gas separation performance test of the CMS hollow fiber membrane adopts a gas permeameter to perform the gas separation performance test on all sample membrane materials by a differential pressure method according to the national standard GB/T1083, the test pressure is 2bar, the test temperature is 26 ℃, the downstream of a sample cell is vacuumized (below 30 Pa) during the test, and the test is started after a period of stability (about 2 h). Putting the carbon molecular sieve membrane component into a test pool to start testing, ending the testing after the permeation quantity of the gas is stable for a period of time, repeating the testing for three times, and calculating the permeation coefficient and the selection coefficient by using the following formula:
wherein P is i ，P j The permeability coefficient of the gases i, j, respectively, α represents the selection coefficient, Q (cm 3 (STP)s -1 ) Represents the volumetric flow rate of the gas at the outlet, l (cm) is the thickness of the membrane, A represents the membrane area (cm) 2 ) Δp (cmHg) represents the pressure differential of the gas i across the membrane. 1 barrer=10 -10 cm 3 (STP)cm(cm 2 scmHg) -1 。
Example 2:
realize high-efficient CO through in situ post oxidation treatment 2 The isolated carbon molecular sieve hollow fiber membrane CMS-30 was prepared by a process differing from example 1 only in:
in step 3), the prepared membrane module is placed in a tube furnace to be heated at 305 ℃ for 30min, compressed air with the pressure of 4bar is sent to the outer side of the shell of the membrane module while being heated, and meanwhile, the air at the inner side of the hollow tube of the membrane module is kept at 1bar, so that a pressure difference is formed. And carrying out gas separation test on the finally obtained membrane subjected to in-situ post-oxidation treatment.
Example 3:
realize high-efficient CO through in situ post oxidation treatment 2 The isolated carbon molecular sieve hollow fiber membrane CMS-60 was prepared by a process differing from example 2 only in: the treatment time was 60min.
The gas properties of the resulting films are shown in the following table:
table 1: post-oxidation treatment of CMS hollow fiber membranes with changes in gas permeability coefficient and selectivity over time
From the above results, it can be seen that the CMS hollow fiber membrane prepared in the above example has CO 2 、N 2 And CH (CH) 4 Has a significant increase in gas permeability coefficient and good CO 2 /N 2 、CO 2 /CH 4 Is selected from the group consisting of (1). CO of CMS hollow fiber membranes treated therein for 60min 2 The permeability coefficient is improved by 4.6 times.
To further illustrate the structural regulation of CMS hollow fiber membranes by in situ post-oxidation treatment, analytical tests were performed on the changes in their interlayer spacing, pore size distribution and carbon structure for untreated and post-oxidized membranes, as shown in fig. 2-4. FIG. 2 shows that the untreated CMS hollow fiber membranes have a layer spacing ofAfter in situ oxidation treatment for different times, the interlayer spacing of the CMS hollow fiber membranes is increased to +.>(30 min) and->(60 min), indicating a more open structure obtained by in situ post oxidation treatment. In addition, as shown in FIG. 3, at +.>Within the scope, post-oxidation-treated CMS hollow fiber membranes are +.>The left and right distribution increases significantly, indicating an increase in sub-nanopores. As can be seen from FIG. 4, sp 3 Hybrid carbon and sp 2 The peak area ratio of the hybridized carbon gradually decreases, indicating that the in-situ oxidation treatment reduces the graphitization degree of the carbon structure. The test shows that the CMS hollow fiber membrane provided by the invention is beneficial to improving CO through the structural regulation and control by in-situ post-oxidation treatment 2 Is penetrated by (a)Sex. Furthermore, analysis of O1s pattern by XPS and CO 2 Adsorption test to further illustrate the variation of surface properties of CMS hollow fiber membranes, it can be seen from FIG. 5 that the post-oxidation treated membranes have increased-COOH groups, favoring CO 2 As can be seen from FIG. 6, CO 2 The adsorption capacity is improved by 2 times. The result reported by the invention provides a new way for the in-situ structure modification of CMS hollow fiber membranes to obtain high-performance membranes in the future.
The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.
Claims (10)
1. The preparation method of the in-situ post-oxidized carbon molecular sieve hollow fiber membrane is characterized by comprising the following steps:
and in an oxidizing atmosphere, applying a forward pressure difference between the shell side and the hollow tube side of the carbon molecular sieve hollow fiber membrane, and performing heating treatment to obtain the carbon molecular sieve hollow fiber membrane subjected to in-situ post-oxidation treatment.
2. The method for preparing an in situ carbon molecular sieve hollow fiber membrane according to claim 1, wherein the oxidizing atmosphere is an air atmosphere or an oxygen atmosphere.
3. The method for preparing an in situ carbon oxide molecular sieve hollow fiber membrane according to claim 1, wherein the forward pressure difference is 1-5 bar.
4. The method for preparing an in-situ carbon molecular sieve hollow fiber membrane according to claim 3, wherein the air pressure on the shell side of the carbon molecular sieve hollow fiber membrane is 2-6 bar, and the air pressure on the hollow tube side of the carbon molecular sieve hollow fiber membrane is 0.8-1.2 bar.
5. The method for preparing an in-situ carbon molecular sieve hollow fiber membrane according to claim 1, wherein in the heating treatment, the heating temperature is 280-330 ℃.
6. The method for preparing an in situ carbon molecular sieve hollow fiber membrane according to claim 1, wherein the method for preparing the carbon molecular sieve hollow fiber membrane comprises the following steps:
s1: mixing microcrystalline cellulose, 1-ethyl-3-methylimidazole acetate and dimethyl sulfoxide to obtain spinning solution; preparing a spinning solution into a hollow fiber membrane by a dry-wet spinning method;
s2: and heating and carbonizing the hollow fiber membrane to obtain the carbon molecular sieve hollow fiber membrane.
7. The method for preparing an in-situ carbon oxide molecular sieve hollow fiber membrane according to claim 6, wherein in the step S1, the content of microcrystalline cellulose in the spinning solution is 10-14 wt%; the mass ratio of the 1-ethyl-3-methylimidazole acetate to the dimethyl sulfoxide is 1 (2-4).
8. The method for preparing an in-situ carbon molecular sieve hollow fiber membrane according to claim 6, wherein in the step S2, the carbonization temperature is 550-650 ℃ and the carbonization time is 6-8 h.
9. An in situ carbon molecular sieve hollow fiber membrane prepared by the method of any one of claims 1 to 8.
10. Use of the in situ carbon dioxide molecular sieve hollow fiber membrane of claim 9 for separation of carbon dioxide from nitrogen and/or carbon dioxide from methane.
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