Preparation method and application of brominated polyphenyl ether mixed matrix membrane containing imino organic cage RCC3

Abstract

The invention discloses a preparation method and application of a brominated polyphenyl ether mixed matrix membrane containing an imino organic cage RCC3, and the preparation method comprises the following steps: weighing BPPO, dissolving the BPPO in a solvent, then adding 4-pyridyl propanol and RCC3 as shown in a formula (I), mixing, and reacting at room temperature for 12-36 hours to obtain a membrane casting solution; and casting the membrane casting solution on a clean glass plate, and carrying out vacuum drying at 60-100 DEG C for 12-36 hours to obtain the BPPO-Py-RCC3 membrane. The invention provides application of the brominated polyphenyl ether mixed matrix membrane containing the imino organic cage RCC3 as an anion exchange membrane in electrodialysis separation of monovalent and multivalent anions. According to the prepared mixed matrix membrane, the ion separation performance and the size stability are enhanced, and the mixed matrix membrane has an ion transmission window with a low swelling rate and a proper size in water and an organic solvent and has a good application effect in electrodialysis separation of monovalent and multivalent anions. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the field of high molecular polymer materials and porous materials, and in particular to a preparation method and application of a brominated polyphenylene ether mixed matrix membrane containing an imine-based organic cage RCC3. Background Art

[0002] In the industrial fields involving resource recovery, seawater desalination and wastewater treatment, there is a need for efficient separation of ions (such as Cl - / SO4 2- ) situation. Membrane separation technology has the advantages of low energy consumption and simple operating equipment, and is considered to be one of the most promising separation technologies. Organic solvent-resistant ion selective membranes directly separate valuable ions and minimize wastewater discharged into the environment, which helps reduce chemical pollution and energy consumption. Some traditional separation membranes will degrade, shed functional groups or swell in organic salt solutions, which is not conducive to ion separation. Therefore, the development of ion selective membranes with excellent organic solvent resistance is an urgent problem to be solved.

[0003] The new porous materials have the characteristics of clear pore structure, permanent pores, and uniform pore size, which can better meet the requirements of ion selective separation. Porous organic cages (POCs) are assembled through van der Waals interactions between isolated molecules with fixed cavities. They have rich porosity and sub-nanometer-sized windows, showing unique structural flexibility and excellent solvent processability. RCC3 is one of the most studied POCs. It is an amine cage compound with good stability and unique tetrahedral symmetry. The effective diameter of the window is about The size is suitable for ion separation. However, the ordered arrangement and assembly of POCs on membranes remains challenging. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of a brominated polyphenylene ether mixed matrix membrane containing an imine organic cage RCC3.

[0005] To solve the above-mentioned purpose, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a brominated polyphenylene ether mixed matrix membrane containing an imine organic cage RCC3, comprising the following steps:

[0007] Weigh BPPO, dissolve it in a solvent, then add 4-pyridine propanol and RCC3 represented by formula (I), mix and react at room temperature for 12 to 36 hours to obtain a casting solution; then cast the casting solution on a clean glass plate, and vacuum dry it at 60 to 100° C. for 12 to 36 hours to obtain a BPPO-Py-RCC3 film, wherein the mass of RCC3 accounts for 7.5-30% of the total mass of BPPO, 4-pyridine propanol and RCC3;

[0008]

[0009] The preparation method of the organic cage RCC3 described in the present invention refers to the document [Adv.Funct.Mater.2024,2314469].

[0010] Preferably, the solvent is N-methylpyrrolidone (NMP).

[0011] Preferably, the mass ratio of BPPO to 4-pyridinepropanol is 4-6:1, preferably 5:1.

[0012] Preferably, the reaction time is 24 h.

[0013] Preferably, the vacuum drying temperature is 80° C. and the drying time is 12 h.

[0014] In a second aspect, the present invention provides a brominated polyphenylene ether mixed matrix membrane containing an imine organic cage RCC3 obtained according to the preparation method described in the first aspect.

[0015] In a third aspect, the present invention provides the use of the brominated polyphenylene ether mixed matrix membrane containing the imine organic cage RCC3 described in the second aspect as an anion exchange membrane in the electrodialysis separation of monovalent and polyvalent anions.

[0016] Preferably, the monovalent anion is Cl- and the polyvalent anion is SO4 2- .

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention prepares a brominated polyphenylene ether mixed matrix membrane containing an imine organic cage RCC3. The prepared mixed matrix membrane has a sub-nanostructured window. At the same time, RCC3 is grafted with brominated polyphenylene ether by chemical cross-linking, which has better chemical stability, thereby enhancing ion separation performance and dimensional stability. The optimized mixed matrix membrane has a low swelling rate and an ion transmission window of suitable size in water and organic solvents. This enables the membrane to have a suitable ion channel, reduce ion transmission resistance, and is beneficial to electrodialysis performance, and has a good application effect in electrodialysis separation of monovalent and polyvalent anions. Description of the drawings:

[0019] Figure 1 They are respectively SEM images of CC3 and RCC3 prepared in Example 1 of the present invention, wherein ab is the SEM image of CC3 dispersed in NMP, and cd is the SEM image of RCC3 dispersed in NMP.

[0020] Figure 2 They are the surface and cross-sectional SEM images of the mixed matrix membranes prepared in Examples 1-5 of the present invention, a, b, c, d are the SEM surface images of BPPO-Py-CC3-7.5, BPPO-Py-RCC3-7.5, BPPO-Py-RCC3-15 and BPPO-Py-RCC3-30, respectively; e, f, g, h are the SEM cross-sectional images of BPPO-Py-CC3-7.5, BPPO-Py-RCC3-7.5, BPPO-Py-RCC3-15 and BPPO-Py-RCC3-30, respectively.

[0021] Figure 3 This is a physical picture of the BPPO-Py-RCC3-15 film prepared in Example 3 of the present invention, which shows the overall appearance of the film, with uniform color and smooth surface.

[0022] Figure 4 CC3 and RCC3 obtained in Example 1 of the present invention 1 H NMR images.

[0023] Figure 5 It is a membrane surface resistance diagram of the anion exchange membrane prepared in Examples 1-5 of the present invention before and after being immersed in 60% ethanol, 60% DMSO and 60% DMAc solutions for 2 days; the figure shows the stability of the membrane in 60% ethanol, 60% DMSO and 60% DMAc solutions. After immersion, the resistance increases slightly but the overall change is not large, indicating that the membrane has good resistance to organic solvents.

[0024] Figure 6 The liquid absorption rate and swelling rate of the membranes prepared in Examples 1-5 of the present invention in water, 60% ethanol, 60% DMSO and 60% DMAc solutions; compared with BPPO-Py, the BPPO-Py-RCC3 membrane shows lower water content and swelling rate in organic solvents, which is mainly attributed to its cross-linked structure reducing its water content and swelling rate.

[0025] Figure 7 Embodiment 2 of the present invention ( Figure 7 a) and 5( Figure 7 b) Cl of the prepared membrane - / SO4 2- Selectivity: The results show that BPPO-Py-RCC3 membrane has high selectivity for Cl ions. Figure 7 It shows that with the increase of RCC3 content, the Cl- / SO4 2- The selectivity was significantly improved, highlighting the key role of RCC3 in optimizing the membrane's ion separation performance.

[0026] Figure 8 Schematic diagram of the electrodialysis device used in Example 7 of the present invention. DETAILED DESCRIPTION

[0027] To further illustrate the technical solution of the present invention, the preferred implementation scheme of the present invention is described below in conjunction with specific examples, but it should be understood that these descriptions are only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention.

[0028] Embodiment 1:

[0029] Preparation of organic cage CC3: Weigh 1g of 1,3,5-trimethylbenzene and put it into a round-bottom flask, slowly add 20mL of dichloromethane, and then add 40μL of trifluoroacetic acid as a catalyst to obtain solution ①. Weigh 1g of (1R,2R)-1,2-cyclohexanediamine and dissolve it in 20mL of dichloromethane to obtain solution ②, then add solution ② dropwise to solution ① and let it stand at room temperature for 4 days. Collect the crude product CC3 by rotary evaporator and then centrifuge and wash with 95% ethanol / 5% dichloromethane (v / v). White powder CC3 is obtained.

[0030] Preparation of organic cage RCC3 containing imine bond: 1g CC3 was dispersed in a mixed solution of dichloromethane / methanol (v:v=1:1), and after it became clear, 0.5g sodium borohydride reducing agent was added, and the reaction was carried out at room temperature for 15h, and then 1mL water was added and stirred at room temperature for 9h. After the reaction was completed, the solvent was removed by rotary evaporation, and impurities were removed by washing with deionized water. Then, two 15mL portions of dichloromethane were used for extraction, and the organic phase was collected and finally vacuum dried to obtain white solid powder RCC3.

[0031] Characterization of organic cages: SEM images of the prepared CC3 and RCC3, 1 H NMR, the results are shown in the attached figure.

[0032] Preparation of BPPO-Py membrane: Weigh 1g of BPPO and 0.2g of 4-pyridine propanol and dissolve them in 30mL of NMP solvent, stir at room temperature for 24h, pour on a clean glass plate, and vacuum dry at 80℃ for 24h. (BPPO, benzyl substitution degree is 0.55, from Shandong Tianwei Co., Ltd.)

[0033] Performance of BPPO-Py membrane: Parameters such as ion exchange capacity, membrane surface resistance, water absorption and swelling rate, SEM image and monovalent selectivity of the prepared membrane are shown in the attached figure. Here, the prepared anion exchange membrane is mainly used for comparative tests. (Test method reference: Small 2024,20,2306313).

[0034] Embodiment 2:

[0035] The preparation process of CC3 and RCC3 is the same as that in Example 1.

[0036] Preparation of BPPO-Py-CC3-0.075 membrane: Weigh 1 g of BPPO and 0.2 g of 4-pyridinepropanol and dissolve them in 15 mL of NMP solvent to obtain a BPPO-Py solution; pour 7.5 wt% (CC3 / (BPPO+Py+CC3)) of CC3 into 15 mL of NMP and ultrasonically disperse it for 30 minutes, then add it to the BPPO-Py solution, stir at room temperature for 24 hours, pour the casting liquid onto a clean glass plate, and vacuum dry it at 80°C for 24 hours.

[0037] The performance of BPPO-Py-CC3-7.5 membrane: ion exchange capacity, membrane surface resistance, water absorption and swelling rate, SEM image and monovalent selectivity are shown in the attached figure. Here, the prepared composite matrix membrane is mainly used for comparative experiments.

[0038] Embodiment 3:

[0039] The preparation process of CC3 and RCC3 is the same as that in Example 1.

[0040] Preparation of BPPO-Py-RCC3-0.075 membrane: Weigh 1g of BPPO and 0.2g of 4-pyridinepropanol and dissolve them in 15mL of NMP solvent to obtain a BPPO-Py solution; pour 7.5wt% (RCC3 / (BPPO+Py+RCC3)) of RCC3 into 15mL of NMP and ultrasonically disperse it for 30min, then add it to the BPPO-Py solution, stir at room temperature for 24h, pour the casting liquid onto a clean glass plate, and vacuum dry it at 80℃ for 24h.

[0041] The performance of BPPO-Py-RCC3-7.5 membrane: parameters such as ion exchange capacity, membrane surface resistance, water absorption and swelling rate, SEM image and monovalent selectivity are shown in the attached figure.

[0042] Embodiment 4:

[0043] The preparation process of CC3 and RCC3 is the same as that in Example 1.

[0044] Preparation of BPPO-Py-RCC3-0.15 membrane: Weigh 1 g of BPPO and 0.2 g of 4-pyridinepropanol and dissolve them in 15 mL of NMP solvent to obtain a BPPO-Py solution; pour RCC3 with a mass ratio of 15 wt% (RCC3 / (BPPO+Py+RCC3)) into 15 mL of NMP and ultrasonically disperse it for 30 minutes, then add it to the BPPO-Py solution, stir at room temperature for 24 hours, pour the casting liquid onto a clean glass plate, and vacuum dry it at 80°C for 24 hours.

[0045] The performance test of BPPO-Py-RCC3-15 membrane is the same as that of Example 2.

[0046] Embodiment 5:

[0047] The preparation process of CC3 and RCC3 is the same as that in Example 1.

[0048] Preparation of BPPO-Py-RCC3-0.3 membrane: Weigh 1g of BPPO and 0.2g of 4-pyridinepropanol and dissolve them in 15mL NMP solvent to obtain BPPO-Py solution; pour RCC3 with a mass ratio of 30wt% (RCC3 / (BPPO+Py+RCC3)) into 15mL NMP and ultrasonically disperse it for 30min, then add it to the BPPO-Py solution, stir at room temperature for 24h, pour the casting liquid onto a clean glass plate, and vacuum dry it at 80℃ for 24h.

[0049] The performance test of BPPO-Py-RCC3-30 membrane is the same as that of Example 2.

[0050] Embodiment 6:

[0051] The films prepared in Examples 1-5 were tested for resistance to organic solvents, and the results are shown in the attached figure. The films were first cut into 3cm×3cm shapes, and then immersed in 60% (v / v) ethanol, 60% (v / v) DMAc and 60% (v / v) DMSO solutions for 90 days, and before and after comparison photos were taken to observe the changes in morphology. The films were then cut into 1cm×4cm sizes, and after drying in an oven for 24 hours, their mass was weighed, their dimensions were measured and recorded, and then after being immersed in ethanol, DMAc and DMSO solutions for 24 hours, their mass was weighed again, their dimensions were measured and recorded, and their liquid absorption rate and swelling rate were calculated according to the formula to evaluate their dimensional stability in organic solvents. The films were cut into 2cm×2cm sizes, immersed in 60% ethanol, 60% DMAc and 60% DMSO solutions for 2 days, and their membrane surface resistance was tested, and the organic solvent resistance of the films was evaluated by comparing the changes before and after.

[0052] Embodiment 7:

[0053] exist Figure 8In the ED device shown, the anion exchange membrane is the membrane prepared in Example 1-5, and the cation exchange membrane is FUJI-CEM, purchased from Fuji Corporation of Japan. -2 By measuring the current density of Cl - and SO4 2- The ion selectivity was evaluated by measuring the concentration changes of ions. The two middle compartments were filled with 80 mL of a mixed solution of 0.05 M NaCl and 0.05 M Na2SO4, and 0.3 M Na2SO4 was pumped into the electrode compartment. The Cl in DC at different time intervals was measured by anion chromatography (Thermo Scientific ICS-5000+). - and SO4 2- ion concentration. Calculate Cl according to the formula - / SO4 2- Selective.

Claims

1. A method for preparing a brominated polyphenylene ether mixed matrix membrane containing an imine organic cage RCC3, characterized in that: The preparation method comprises the following steps: Weigh BPPO, dissolve it in a solvent, then add 4-pyridine propanol and RCC3 represented by formula (I), mix and react at room temperature for 12 to 36 hours to obtain a casting solution; then cast the casting solution on a clean glass plate, and vacuum dry it at 60 to 100° C. for 12 to 36 hours to obtain a BPPO-Py-RCC3 film, wherein the mass of RCC3 accounts for 7.5-30% of the total mass of BPPO, 4-pyridine propanol and RCC3; 2. The preparation method according to claim 1, characterized in that: The solvent is N-methylpyrrolidone.

3. The preparation method according to claim 1, characterized in that: The mass ratio of BPPO to 4-pyridinepropanol is 4-6:

1.

4. The preparation method according to claim 3, characterized in that: The mass ratio of BPPO to 4-pyridinepropanol is 5:

1.

5. The preparation method according to claim 1, characterized in that: The reaction time is 24h.

6. The preparation method according to claim 1, characterized in that: The vacuum drying temperature is 80°C and the drying time is 12 h.

7. A brominated polyphenylene ether mixed matrix membrane containing imine organic cage RCC3 prepared according to the preparation method of claims 1-6.

8. Use of the brominated polyphenylene ether mixed matrix membrane containing imine organic cage RCC3 as claimed in claim 7 as an anion exchange membrane in electrodialysis separation of monovalent and polyvalent anions.

9. The use according to claim 8, characterized in that: The monovalent anion is Cl - , the polyvalent anion is SO4 2- .

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