Mixed matrix membrane with organic metal framework continuous path as well as preparation method and application of mixed matrix membrane
By forming continuous MOF channels in the polyethylene oxide matrix, the problem of mutual constraint between the selectivity and permeability of polymer membranes is solved, achieving efficient carbon dioxide separation and enhanced gas separation performance.
Patent Information
- Application Number
- CN202511030358.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-25
- Publication Date
- 2025-10-31
AI Technical Summary
Existing polymer membranes suffer from a trade-off between selectivity and permeability in carbon dioxide separation, and are prone to aggregation when loaded with high-MOF, leading to a decline in gas separation performance.
A hybrid matrix membrane was prepared by using nanoscale MOF and cross-linked polyethylene glycol diacrylate to form continuous channels in a polyethylene oxide matrix, and by solution blending, hot pressing, isothermal crystallization and photocrosslinking to form a highly continuous MOF pathway.
It improves the permeation flux and selectivity of carbon dioxide, enhances the gas separation performance of the membrane, and provides good mechanical properties, avoiding the performance degradation caused by MOF aggregation.
Smart Images
Figure CN120860841A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer materials and gas separation membranes, and relates to a hybrid matrix membrane with a continuous pathway of organometallic framework, its preparation method and application. Background Technology
[0002] Carbon dioxide capture and separation are of great significance for environmental protection, industrial production, and energy security. Membrane-based carbon dioxide capture / separation methods have attracted widespread attention in recent years due to their advantages such as low energy consumption, high efficiency, and ease of operation. Based on the material of the separation membrane, they can be classified into inorganic membranes, polymer membranes, and mixed-matrix membranes. Inorganic membranes exhibit excellent separation performance, but their poor stability and poor film-forming properties remain persistent challenges. Polymer membranes possess good film-forming properties, but the selectivity and permeability of conventional polymer membranes are mutually restrictive, making it difficult to exceed the Robeson limit, which significantly limits their widespread application. Based on the excellent film-forming and processing properties of polymer materials and the superior gas separation performance of metal-organic frameworks (MOFs), mixed-matrix membranes with the former as the matrix and the latter as the dispersed phase have emerged. In this field, reducing the distance between adjacent MOFs and constructing continuous MOF channels are key to improving gas separation performance. Therefore, developing a preparation strategy for mixed-matrix membranes with continuous pathways in an organometallic framework is essential. However, current strategies for obtaining MOF continuous pathways by increasing MOF loading face the drawback of severe MOF aggregation, so the technology for constructing highly continuous MOF pathways still has certain shortcomings.
[0003] Polyethylene oxide (PEO) is often chosen as a polymer separation membrane material due to its excellent carbon dioxide (CO2) solubility and processability, and it also has the characteristic of being crystallizable. MOFs themselves have advantages in the field of gas separation due to their diverse chemical composition, large specific surface area, and tunable pore structure. Summary of the Invention
[0004] The purpose of this invention is to provide a hybrid matrix membrane with a continuous pathway of an organometallic framework, its preparation method and application. The membrane has a continuous MOF arrangement structure and is composed of a highly continuous organometallic framework and an amorphous polyethylene oxide matrix. It can be applied to the field of CO2 capture and separation.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] This invention first provides a hybrid matrix membrane with continuous pathways of an organometallic framework.
[0007] The membrane has a continuous MOF arrangement structure, wherein the continuous MOF channels are composed of MOF with a particle size of nanoscale and cross-linked polyethylene glycol diacrylate (PEGDA). The channels run through the polyethylene oxide matrix, forming a three-dimensional network of continuous channels in the matrix.
[0008] This invention also provides a method for preparing a hybrid matrix membrane with continuous pathways of an organometallic framework, comprising:
[0009] Step 1: Dissolve polyethylene oxide, polyethylene glycol diacrylate and initiator in a solvent to obtain a solution, and then mix and stir the solution with the nano-sized MOF dispersion to obtain a mixed solution;
[0010] Step 2: Spread the mixed solution from Step 1 onto a petri dish to obtain the blend;
[0011] Step 3: Hot-press the blend from Step 2, and then perform isothermal crystallization to obtain the crystallized product;
[0012] Step 4: Irradiate the crystallized product obtained in Step 3 under a UV lamp to crosslink it, thereby obtaining a mixed matrix membrane;
[0013] Step 5: Heat the mixed matrix membrane obtained in Step 4 to 80-150℃ to melt for 5-10 minutes, and then quickly place it in liquid nitrogen for rapid cooling to obtain a mixed matrix membrane with continuous pathways of an organometallic framework.
[0014] Preferably, the MOF in the nanoscale MOF dispersion of step one is selected from UiO-66, UiO-66-NH2, ZIF-8 or ZIF-94.
[0015] Preferably, the initiator in step one is 1-hydroxycyclohexylphenyl ketone or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.
[0016] Preferably, the mass ratio of polyethylene oxide to polyethylene glycol diacrylate in step one is (7-9):(1-3), and the mass ratio of polyethylene oxide to nanoscale MOF in the MOF dispersion is (7-9):(1-3).
[0017] Preferably, the coating process described in step two involves evaporating the solvent at 25–40°C for 24–48 hours, followed by drying in an oven at 60–80°C for 12–24 hours.
[0018] Preferably, the hot pressing in step three is performed at 90–150°C and 5–10 MPa for 5–10 minutes.
[0019] Preferably, the isothermal crystallization in step three is carried out at a temperature of 40–57°C for a time of 0.5–2 hours.
[0020] Preferably, the irradiation time in step four is 100 seconds.
[0021] The present invention also provides the application of the above-mentioned hybrid matrix membrane with continuous pathways of organometallic framework in the field of CO2 capture and separation.
[0022] Beneficial effects of the present invention
[0023] 1) This invention provides a hybrid matrix membrane with continuous organometallic framework pathways, its preparation method, and its application. The hybrid matrix membrane is composed of a highly continuous organometallic framework and an amorphous polyethylene oxide (PEO) matrix. The method involves mixing a nanoscale organometallic framework, polyethylene oxide, polyethylene glycol diacrylate, and a photoinitiator via solution blending, followed by solvent evaporation, melt pressing to prepare a thin film, isothermal crystallization treatment, and then photo-initiated crosslinking. PEO has a tendency to crystallize easily; during isothermal crystallization, the nanoscale organometallic framework, polyethylene glycol diacrylate, and photoinitiator can be expelled into its amorphous region, forming highly continuous organometallic framework channels. Subsequent photo-crosslinking treatment forms a crosslinked amorphous network, while simultaneously reducing the crystallinity of the PEO and maintaining its amorphous state after high-temperature quenching, thus fixing the continuous organometallic framework pathways. The obtained thin film exhibits 1.58 times and 1.21 times the carbon dioxide flux and gas separation selectivity of a hybrid matrix membrane with a uniformly dispersed organometallic framework, respectively.
[0024] 2) This invention uses PEO as the polymer matrix and arranges pre-uniformly dispersed MOFs through the crystallization behavior of PEO to obtain highly continuous MOF channels. These channels have three-dimensional continuity within the polyethylene oxide matrix, and amorphous pathways within the PEO matrix can be obtained through quenching. The interlacing of these two pathways provides excellent conditions for CO2 transport. This invention avoids the problem of decreased gas separation performance of mixed matrix membranes caused by MOF agglomeration under high MOF loading, and provides a new approach for preparing high-performance mixed matrix membranes with continuous MOF pathways.
[0025] 3) This invention utilizes photo-initiated crosslinking of polyethylene glycol diacrylate (PEG diacrylate) to selectively crosslink the amorphous region, which not only inhibits the diffusion and migration of MOF and PEG diacrylate but also provides excellent mechanical properties for the mixed matrix film. It also significantly suppresses PEO crystallization.
[0026] 4) This invention selects polyethylene oxide and polyethylene glycol diacrylate as polymer matrix. Their ether bond structure has a high affinity for CO2. At the same time, using polymer as matrix has the advantages of low price, excellent processing performance and simple industrial preparation. Attached Figure Description
[0027] Figure 1 Schematic diagram of MOF arrangement induced by PEO crystallization and construction of continuous pathways;
[0028] Figure 2 Transmission photograph of a 1 MOF uniformly dispersed mixed matrix film as a comparative example.
[0029] Figure 3 This is a transmission image of a polyethylene-based hybrid matrix film with continuous MOF channels, as shown in Example 1.
[0030] Figure 4 The graphs show the performance of the mixed matrix membranes before and after MOF arrangement in Comparative Example 1 and Example 1. Detailed Implementation
[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the scope of the specific embodiments described.
[0032] This invention first provides a hybrid matrix membrane with a continuous pathway of an organometallic framework, such as... Figure 1 As shown, the film thickness ranges from 1 to 150 μm. This film possesses a continuous MOF (Metal-Oxide-Factory) arrangement structure, where the continuous MOF channels are composed of nano-sized MOF particles and a cross-linked polyethylene glycol diacrylate (PEGDA) network. These channels penetrate the polyethylene oxide matrix, forming a three-dimensional network of continuous channels within the matrix. The highly continuous MOF channels are continuous amorphous regions with widths of 10 nm to 40 nm, formed by isothermal crystallization of the polyethylene oxide matrix. The amorphous polyethylene oxide matrix itself is formed by high-temperature melting of the mixed matrix film followed by quenching in liquid nitrogen, creating amorphous polyethylene oxide transport channels. The highly continuous MOF channels provide pathways for CO2 diffusion, while the PEGDA cross-linked network provides the overall mechanical properties of the film. Furthermore, the PEGDA cross-linked network effectively reduces the crystallinity of polyethylene oxide, allowing it to maintain its amorphous state after quenching.
[0033] This invention also provides a method for preparing a hybrid matrix membrane with continuous pathways of an organometallic framework, comprising:
[0034] Step 1: Dissolve polyethylene oxide, polyethylene glycol diacrylate and initiator in a solvent to obtain a solution, and then mix the solution with the nano-sized MOF dispersion solution. The stirring time is preferably 12-72 hours to obtain a mixed solution.
[0035] In step one, the solvent is preferably deionized water, ethanol, chloroform, or a mixture of ethanol and water (the volume ratio of ethanol to water in the mixed solvent is preferably 7:3); the dissolution temperature is preferably 25–50°C, more preferably 40°C; the dissolution time is preferably 12–48 h, more preferably 24 h; and the total mass fraction of polyethylene oxide and polyethylene glycol diacrylate in the solution is preferably 1–10 wt%, more preferably 5 wt%.
[0036] The nanoscale MOF dispersion is preferably prepared as a solution with a concentration of 1 mg / ml to 10 mg / ml. The MOF is dispersed by ultrasound, stirring, or a combination of both. During dispersion, the dispersion temperature is preferably 25–50°C, more preferably 40°C. The ultrasound time is preferably 0.5–2 h, more preferably 1.5 h. The stirring time is preferably 12–48 h, more preferably 12 h. The solvent used in the dispersion is preferably deionized water, ethanol, chloroform, or a mixture of ethanol and water (the volume ratio of ethanol to water in the mixed solvent is preferably 7:3). The MOF in the nanoscale MOF dispersion is preferably selected from UiO-66, UiO-66-NH2, ZIF-8, or ZIF-94, more preferably UiO-66-NH2 with a particle size of 10 nm.
[0037] The preferred mass ratio of polyethylene oxide to polyethylene glycol diacrylate is (7-9):(1-3); the preferred mass ratio of polyethylene oxide to nanoscale MOF in the MOF dispersion is (7-9):(1-3); the preferred initiator is the photoinitiator 1-hydroxycyclohexylphenyl ketone or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and the preferred amount of initiator added is 1 wt% of the mass fraction of polyethylene glycol diacrylate.
[0038] Step 2: The mixed solution from Step 1 is coated onto a petri dish, preferably with solvent evaporation at 25–40°C for 24–48 hours, and then transferred to an oven at 60–80°C for drying for 12–24 hours to obtain the blend; the mixed solution is preferably evaporated at room temperature for 24–48 hours before coating.
[0039] Step 3: The blend from Step 2 is hot-pressed, preferably at 90-150°C and 5-10 MPa for 5-10 minutes, and then isothermal crystallization is performed to obtain the crystallized product; preferably isothermal crystallization is performed at 40-57°C for 0.5-2 hours; more preferably isothermal crystallization is performed at 43°C for 0.5 hours.
[0040] Step 4: Irradiate the crystallized product obtained in Step 3 under an ultraviolet lamp for a preferred irradiation time of 100 seconds to perform cross-linking and obtain a mixed matrix film.
[0041] Step 5: Heat the mixed matrix membrane obtained in Step 4 to 80-150℃ to melt for 5-10 minutes, and then quickly place it in liquid nitrogen for rapid cooling to obtain a mixed matrix membrane with continuous pathways of an organometallic framework.
[0042] The present invention will be further described in detail below with specific embodiments. The polyethylene oxide (PEO) used in the embodiments is produced by Sigma-Aldrich, USA; the polyethylene glycol diacrylate (PEGDA) is produced by Shanghai Aladdin Biochemical Technology Co., Ltd.; and the 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone is produced by Shanghai Aladdin Biochemical Technology Co., Ltd.
[0043] Comparative Example 1
[0044] Prepare a mixed solvent of ethanol and water with a volume fraction of 7:3. Dissolve 0.05 g of UiO-66-NH2 in 50 ml of the mixed solvent to prepare a 1 mg / ml solution. Sonicate for 2 h and stir for 48 h to prepare a well dispersed UiO-66-NH2 solution.
[0045] 0.45g polyethylene oxide, 0.05g polyethylene glycol diacrylate, and 0.0005g 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone were placed in a mixed solvent of ethanol and water (preferably with a volume ratio of 7:3) to prepare a solution with a total mass fraction of 5 wt% for polyethylene oxide and polyethylene glycol diacrylate, and stirred for 48 h.
[0046] The two solutions were mixed and stirred for 48 hours. The mixture was then left to evaporate at room temperature with an open stirring chamber for 48 hours. The resulting solution was then used to form a film in a petri dish. The solvent was evaporated at 40°C for 48 hours, and then the film was transferred to an 80°C oven to dry for 24 hours.
[0047] The above-mentioned mixed matrix membrane was hot-pressed at 100°C and 10MPa for 10 minutes in a flat vulcanizing machine, then quenched in liquid nitrogen, and then irradiated with ultraviolet light for 100 seconds to initiate cross-linking, thus obtaining a MOF uniformly dispersed polyoxyethylene mixed matrix membrane.
[0048] Example 1
[0049] Prepare a mixed solvent of ethanol and water with a volume fraction of 7:3. Dissolve 0.05 g of UiO-66-NH2 in 50 ml of the mixed solvent to prepare a 1 mg / ml solution. Sonicate for 2 h and stir for 48 h to prepare a well dispersed UiO-66-NH2 solution.
[0050] 0.45g polyethylene oxide, 0.05g polyethylene glycol diacrylate, and 0.0005g 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone were placed in a mixed solvent of ethanol and water (preferably with a volume ratio of 7:3) to prepare a solution with a total mass fraction of 5 wt% for polyethylene oxide and polyethylene glycol diacrylate, and stirred for 48 h.
[0051] The two solutions were mixed and stirred for 48 hours. The mixture was then left to evaporate at room temperature for 48 hours. The resulting solution was then used to form a film in a petri dish. The solvent was evaporated at 40°C for 48 hours, and then the film was transferred to an 80°C oven to dry for 24 hours.
[0052] The above-mentioned mixed matrix membrane was hot-pressed at 100°C and 10 MPa for 10 min in a flat vulcanizing machine, and then isothermally crystallized at 43°C for 0.5 h. After being irradiated with ultraviolet light for 100 s to initiate cross-linking, the resulting sample was heated to 100°C to melt for 10 min and then quenched in liquid nitrogen to obtain a polyoxyethylene mixed matrix membrane with continuous MOF channels.
[0053] The product of Comparative Example 1 was characterized by transmission, and the results are as follows: Figure 2 As shown. Figure 2 As shown, the polyoxyethylene mixed matrix film exhibits a uniform MOF distribution and does not form MOF pathways.
[0054] The product of Example 1 was characterized by transmission, and the results are as follows: Figure 3 As shown. Figure 3 As shown, the polyoxyethylene mixed matrix film after isothermal crystallization has a continuous MOF pathway, and the width of the continuous MOF pathway is about 10 nm.
[0055] Performance tests were conducted on Comparative Example 1 and Example 1, and the results are as follows: Figure 4 As shown. Figure 4 As shown, the MOF-uniformly distributed mixed matrix membrane exhibits a CO2 permeation flux of 96.0 Barrer and a CO2 / N2 selectivity of 79.3. The MOF-continuous mixed matrix membrane exhibits a CO2 permeation flux of 152.0 Barrer and a CO2 / N2 selectivity of 96.2%. Its CO2 permeation flux and selectivity are 1.58 times and 1.21 times that of the MOF-uniformly distributed mixed matrix membrane, respectively.
[0056] The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above embodiments. Any embodiment that meets the requirements of the present invention is within the protection scope of the present invention.
Claims
1. A hybrid matrix membrane with a continuous pathway of an organometallic framework, characterized in that, The membrane has a continuous MOF arrangement structure, wherein the continuous MOF channels are composed of MOF with a particle size of nanometers and cross-linked polyethylene glycol diacrylate. The channels run through the polyethylene oxide matrix, forming a three-dimensional network of continuous channels in the matrix.
2. The method for preparing a hybrid matrix membrane with continuous pathways of an organometallic framework according to claim 1, characterized in that, include: Step 1: Dissolve polyethylene oxide, polyethylene glycol diacrylate and initiator in a solvent to obtain a solution, and then mix and stir the solution with the nano-sized MOF dispersion to obtain a mixed solution; Step 2: Spread the mixed solution from Step 1 onto a petri dish to obtain the blend; Step 3: Hot-press the blend from Step 2, and then perform isothermal crystallization to obtain the crystallized product; Step 4: Irradiate the crystallized product obtained in Step 3 under a UV lamp to crosslink it, thereby obtaining a mixed matrix membrane; Step 5: Heat the mixed matrix membrane obtained in Step 4 to 80-150℃ to melt for 5-10 minutes, and then quickly place it in liquid nitrogen for rapid cooling to obtain a mixed matrix membrane with continuous pathways of an organometallic framework.
3. The method for preparing a hybrid matrix membrane with continuous pathways of an organometallic framework according to claim 2, characterized in that, In step one, the MOF in the nanoscale MOF dispersion is selected from UiO-66, UiO-66-NH2, ZIF-8, or ZIF-94.
4. The method for preparing a hybrid matrix membrane with continuous pathways of an organometallic framework according to claim 2, characterized in that, The initiator mentioned in step one is 1-hydroxycyclohexylphenyl ketone or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.
5. The method for preparing a hybrid matrix membrane with continuous pathways of an organometallic framework according to claim 2, characterized in that, The mass ratio of polyethylene oxide to polyethylene glycol diacrylate in step one is (7-9):(1-3), and the mass ratio of polyethylene oxide to MOF in the nanoscale MOF dispersion is (7-9):(1-3).
6. The method for preparing a hybrid matrix membrane with continuous pathways of an organometallic framework according to claim 2, characterized in that, The coating process described in step two involves evaporating the solvent at 25–40°C for 24–48 hours, followed by drying in an oven at 60–80°C for 12–24 hours.
7. The method for preparing a hybrid matrix membrane with a continuous pathway of an organometallic framework according to claim 2, characterized in that, The hot pressing described in step three is performed at 90–150°C and 5–10 MPa for 5–10 minutes.
8. The method for preparing a hybrid matrix membrane with continuous pathways of an organometallic framework according to claim 2, characterized in that, The isothermal crystallization in step three is carried out at a temperature of 40–57°C for 0.5–2 hours.
9. The method for preparing a hybrid matrix membrane with a continuous pathway of an organometallic framework according to claim 2, characterized in that, The irradiation time described in step four is 100 seconds.
10. The application of the hybrid matrix membrane with continuous pathways of the organometallic framework as described in claim 1 in the field of CO2 capture and separation.