CN114288881B - ZIFs mixed matrix composite nanofiltration membrane as well as preparation method and application thereof - Google Patents
ZIFs mixed matrix composite nanofiltration membrane as well as preparation method and application thereof Download PDFInfo
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Abstract
The invention belongs to the technical field of nanofiltration membranes, and particularly relates to a ZIFs mixed matrix composite nanofiltration membrane, and a preparation method and application thereof. The method comprises the following steps: 1) preparation of a functional support membrane, 2) soaking in a metal salt solution, 3) surface reaction to generate a selective separation layer and ZIFs, and 4) post-treatment. According to the technical scheme, the ZIFs and the selective separation layer are synchronously synthesized in situ in the aqueous solution to prepare the low molecular weight cutoff ZIFs mixed matrix composite nanofiltration membrane, so that the composite nanofiltration membrane has a high-efficiency cutoff effect on small molecular pollutants and has high selective permeability on inorganic salts. Because the ZIFs and the selective separation layer are synchronously synthesized in situ, the method effectively solves the problem of agglomeration of the hydrophobic ZIFs in the selective separation layer of the composite nanofiltration membrane.
Description
Technical Field
The invention belongs to the technical field of nanofiltration membranes, and particularly relates to a ZIFs mixed matrix composite nanofiltration membrane, and a preparation method and application thereof.
Background
The membrane separation technology has the characteristics of low energy consumption, high separation efficiency, operational flexibility and the like, and is considered as a potential choice for sustainable wastewater treatment. Compared with other separation membranes, the nanofiltration membrane has high interception effect on molecules with molecular weight of 200-1000, so that the nanofiltration membrane is more suitable for treating textile industrial wastewater. However, the most common commercial nanofiltration membrane on the market is prepared by an interfacial polymerization method, and can effectively remove macromolecular dyes, and simultaneously can retain multivalent ions with the same high efficiency (more than 90%), and even can retain monovalent ions to the level of 30-60%.
In order to solve this problem, the preparation of nanofiltration membranes with a loose structure is a potentially viable process. In contrast to dense nanofiltration membranes, a nanofiltration membrane separation layer with a loose structure can simultaneously accelerate the passage of salts and increase the water flux. The concept of loose nanofiltration membrane was first proposed in 2004 by Van der Bruggen et al, and the membrane showed a very significant retention effect on dye molecules and at the same time enabled inorganic salts to pass through the membrane surface rapidly. Layer-by-layer self-assembly is one of the main methods for preparing the nanofiltration membrane, and a selective separation layer is formed by alternately depositing two polyelectrolytes with opposite charges. The selectivity of the polyelectrolyte material is very wide, and moreover, the controllability of preparation parameters (deposition time, number of layers of polyelectrolyte and the like) and the charge property of the surface of the membrane can regulate and control the structure of the membrane and realize the separation of macromolecular dyes and small-size inorganic salts through a screening effect and a Douchan effect. Spong Uk Hong et al [ spong Uk Hong, matthew d.miller, and Merlin l.bruening.ind.eng.chem.res.45 (2006) 6284-6288] loose nanofiltration membranes were prepared by alternately depositing polystyrene sulfonate and polyallylamine hydrochloride on porous alumina support membranes by layer-by-layer self-assembly. When the number of layers formed by combining the two polyelectrolytes reaches 4.5, the retention rate of the obtained nanofiltration membrane on various reactive dyes reaches a level close to 100%, and the retention rate on sodium chloride is less than 20%.
The mixed matrix composite nanofiltration membrane can be prepared by introducing the nano material into the membrane, and is also one of effective methods for enabling the membrane to have a loose structure. Incorporation of the nanomaterial into the polymer film provides a channel for water molecules at the interface between the polymer and the nanomaterial, thereby also allowing ions to pass more easily. Junyong Zhu et al [ Junyong Zhu, miaoniao Tian, yatao Zhuang, haoqin Zhuang, jundun Liu.chemical Engineering journal.265 (2015) 184-193] mixed chitosan with montmorillonite, and prepared loose nanofiltration membranes with retention of activated red 49 and activated black 5 exceeding 90% but incapable of effectively retaining inorganic salts such as NaCl by a phase inversion method. Similarly, qi Zhang et al [ Qi Zhang, lin Fan, zhen Yang, runnan Zhang, ya-nan Liu, mingrui He, yanlei Su, zhongyi Jiang. Applied Surface science 410 (2017) 494-504] introduced titanium dioxide in the polyamide separation layer, not only with ultra-high selectivity for separation of dye and salt, but also with nearly 5-fold increase in membrane flux. However, the addition of inorganic materials also has an inevitable problem, that is, film defects due to poor compatibility with polymers.
Metal Organic Framework (MOF) materials are a new class of nanomaterials that bind metal ions and organic ligands, but are well compatible with polymers. In addition, the MOF material also has the characteristics of ultrahigh specific surface area, high porosity, adjustable chemical composition and the like, so that the MOF material is very suitable for being applied to the preparation of the composite nanofiltration membrane. 15342-15355 of Libin Yang et al [ Libin Yang, zhan Wang, jinglong Zhang. Journal of Materials Chemistry A.5 (2017) ]]ZIF-8 nano-particles are generated in situ on a hydrolyzed polyacrylonitrile support membrane in an interface synthesis mode, and the prepared nano-filtration membrane has a good separation effect on dyes such as congo red and methylene blue and has low interception on various inorganic salts. Furthermore, the membrane flux was greatly improved by ZIF-8. However, in this study, n-hexane has strong volatility and toxicity as a solvent for synthesizing dimethyl imidazole of ZIF-8. Therefore, if water can be used for replacing n-hexane for ZIF-8 synthesis, the harm to human body or environment caused in the preparation process can be greatly reduced, and the preparation method is more green and environment-friendly. Yichang Pan et al [ Yichang Pan, yunyang Liu, gaofeng Zeng, lan Zhao, zhiping Lai. Chem. Commun.47 (2011) 2071-2073]Firstly, a method for synthesizing ZIF-8 in an aqueous solution system is proposed. ZIF-8 being a metal ion Zn 2+ And dimethylimidazole, and the sameZIF-67 (Co as a metal ligand) which is a member of the ZIF family 2+ ) The difference from ZIF-8 is only in the use of metal ions. Therefore, the preparation of a novel composite nanofiltration membrane under the condition of completely using the aqueous solution has great potential.
Disclosure of Invention
The invention aims to provide a ZIFs mixed matrix composite nanofiltration membrane as well as a preparation method and application thereof. According to the invention, the ZIFs mixed matrix composite nanofiltration membrane is prepared by synchronously synthesizing the ZIFs and the selective separation layer in situ in an aqueous solution, so that the composite nanofiltration membrane has a high-efficiency interception effect on small-molecular pollutants and has high selective permeability on small-molecular organic matters and inorganic salts. Due to the simultaneous in situ synthesis of ZIFs and selective separation layers. Therefore, the method effectively solves the agglomeration problem of the hydrophobic ZIFs in the selective separation layer of the composite nanofiltration membrane.
The technical scheme of the invention is as follows:
a preparation method of a mixed matrix composite nanofiltration membrane comprises the following preparation steps:
1) Preparing a functional support film:
which comprises the following steps:
1a) Dissolving polyacrylonitrile in a first organic solvent, standing and defoaming to obtain a membrane casting solution;
1b) Coating the membrane casting solution obtained in the step 1 a) on non-woven fabrics in a scraping way, preparing a polymer support membrane by a non-solvent induced phase inversion method, soaking the polymer support membrane in NaOH solution, taking out the polymer support membrane, and washing the surface of the membrane by deionized water until the washing water is neutral to obtain a functionalized support membrane;
alternatively, it comprises the steps of:
1c) Blending the water-insoluble polymer with negative charges into a second organic solvent of the main polymer, and then preparing the functionalized support membrane by a phase inversion method;
2) Soaking in a metal salt solution:
soaking the functionalized support membrane obtained in the step 1) in a metal salt solution, taking out the membrane, and washing the surface of the membrane with deionized water;
3) Surface reactions to produce selective separation layers and ZIFs:
preparing a mixed solution of polycation electrolyte and dimethyl imidazole, pouring the mixed solution on the surface of the functionalized support membrane prepared in the step 2), standing, reacting, and washing the surface of the membrane with deionized water to remove unreacted substances;
4) And (3) post-treatment:
and (4) performing glycerin soaking and high-temperature drying post-treatment on the membrane obtained in the step 3) to finally obtain the mixed matrix composite nanofiltration membrane.
In the technical scheme, the surface of the functionalized support membrane prepared in the step 2) is provided with a part of substrates for in-situ synthesis of ZIFs and a selective separation layer, the mixed solution in the step 3) is provided with the other part of substrates for in-situ synthesis of ZIFs and the selective separation layer, and the ZIFs and the selective separation layer are synchronously synthesized in situ through mixing and standing reaction of the two.
Due to the synchronous in-situ synthesis of the ZIFs and the selective separation layer, the problem of agglomeration of the hydrophobic ZIFs in the selective separation layer of the composite nanofiltration membrane can be effectively solved.
Specifically, the method comprises the following steps:
in the step 1 a), the mass percent of solute in the casting solution is 14-25%; the first organic solvent is N, N-dimethylacetamide, N-dimethylformamide, N-methylpyrrolidone or dimethyl sulfoxide;
in the step 1 b), the mass concentration of the NaOH solution is 2-15%; the solvent of the NaOH solution is water, methanol or ethanol; the soaking treatment temperature is 20-60 deg.C, and the treatment time is 1-60min.
Specifically, in step 1 c):
the main polymer is selected from any one of polyether sulfone, polysulfone or polyphenol;
the water-insoluble polymer with negative charge is selected from any one of sulfonated polyether ether ketone, styrene-maleic anhydride copolymer or carboxylated polysulfone;
the second organic solvent is N, N-dimethylacetamide, N-dimethylformamide, N-methylpyrrolidone or dimethyl sulfoxide.
Specifically, in the step 2), the metal salt solution is one of zinc nitrate or cobalt nitrate, the mass concentration range of the metal salt solution is 0.1-3%, and the soaking time is 1-12 hours.
Specifically, in step 3):
the polycation electrolyte is one of polyethyleneimine, polydiallyldimethylammonium chloride or dopamine;
the mass concentration range of the polycation electrolyte is 0.1-0.5%, the mass concentration range of the 2-methylimidazole is 0.1-3%, and the reaction time is 5-120min.
Specifically, in the step 4):
the mass concentration of the glycerol solution is 5-15%, and the soaking time is 5-60min;
the high temperature treatment temperature is 60-120 deg.C, and the time is 5-20min.
The invention also provides the ZIFs mixed matrix composite nanofiltration membrane prepared by the preparation method.
In particular, the molecular weight cut-off range is 200-400Da.
The invention also provides application of the ZIFs mixed matrix composite nanofiltration membrane as a high-flux selective nanofiltration membrane.
The ZIFs mixed matrix composite nanofiltration membrane provided by the invention still has high selectivity on small molecular organic matters and inorganic salts under the performance of high flux, and particularly has high interception on the small molecular organic matters and high passing on the inorganic salts. Based on the performance, the method can be used for removing small-molecule pollutants and recovering inorganic salts.
Detailed description of the preferred embodiments
The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.
Example 1
1) Weighing 9.6g of Polyacrylonitrile (PAN) as a solute, adding the solute into 50.4g of N, N-dimethylacetamide (DMAc), continuously stirring at the constant temperature of 80 ℃ until the PAN is completely dissolved, and standing and defoaming to obtain a membrane casting solution;
2) Pouring the membrane casting solution on non-woven fabric, scraping the membrane casting solution into a membrane with the thickness of 200 mu m, and quickly placing the membrane in deionized water for forming until the solvent is completely exchanged to obtain a PAN membrane;
3) Weighing 50g of sodium hydroxide (NaOH) and adding the sodium hydroxide into 950g of deionized water, continuously stirring until the NaOH is completely dissolved to obtain a NaOH solution with the mass concentration fraction of 5%, and heating the NaOH solution to 50 ℃ for later use;
4) Putting the PAN membrane in the step 2) into the NaOH solution in the step 3) for hydrolysis, taking out the PAN membrane after 30min, and washing the PAN membrane with a large amount of deionized water until the surface is electrically neutral to obtain a Hydrolyzed Polyacrylonitrile (HPAN) support membrane;
5) 1.1g of cobalt nitrate hexahydrate (Co (NO) was weighed 3 ) 2 ) Adding 300g of deionized water, stirring until the mixture is completely dissolved, and diluting by 40 times to obtain Co (NO) for standby 3 ) 2 A solution;
6) Weighing 0.25g of branched Polyethyleneimine (PEI) aqueous solution with the molecular weight of 60000 into a 250mL volumetric flask, and adding deionized water to prepare a PEI solution with the concentration of 1 g/L;
7) Weighing 5.2g of 2-methylimidazole (Hmim), adding 20mL of the PEI solution obtained in step 6), performing ultrasonic treatment until the PEI solution is completely dissolved, and diluting the PEI solution by 40 times by using the PEI solution to obtain a Hmim/PEI mixed solution
8) Soaking the HPAN support film obtained in the step 4) in Co (NO) 3 ) 2 In solution, after 5 hours it was removed and the membrane surface rinsed with copious amounts of deionized water until free of Co (NO) 3 ) 2 Solution residue;
9) Pouring 20mL of an Hmim/PEI mixed solution onto the HPAN supporting membrane obtained in the step 8), reacting for 30min, pouring out a PEI solution, and washing away the PEI solution remained on the HPAN supporting membrane by deionized water to obtain a ZIF-67-PEI/HPAN membrane;
10 30g of glycerol is weighed, 270g of deionized water is added, and a glycerol solution is obtained after uniform stirring;
11 Soaking the ZIF-67-PEI/HPAN membrane in a glycerol solution, taking out after 30min, directly putting into an oven with the temperature of 80 ℃, and taking out after 10min to obtain the final ZIF-67-PEI/HPAN positively charged mixed matrix composite nanofiltration membrane.
The composite prepared in this exampleThe retention rate of the membrane to PEG200 solution with the concentration of 0.1g/L reaches 87.4 percent, and the membrane flux is 42.7L/(m) 2 ·h·bar)。
Example 2
1) Weighing 9.6g of Polyacrylonitrile (PAN) as a solute, adding the solute into 50.4g of N, N-dimethylacetamide (DMAc), continuously stirring at the constant temperature of 80 ℃ until the PAN is completely dissolved, and standing and defoaming to obtain a casting solution;
2) Pouring the membrane casting solution on a non-woven fabric, selecting a membrane scraping knife with the thickness of 200 mu m to scrape the membrane casting solution into a membrane, and quickly placing the membrane casting solution into deionized water for forming until the solvent is completely exchanged to obtain a PAN membrane;
3) Weighing 100g of sodium hydroxide (NaOH) and adding the sodium hydroxide into 900g of deionized water, continuously stirring until the NaOH is completely dissolved to obtain a NaOH solution with the mass concentration fraction of 10%, and heating the NaOH solution to 50 ℃ for later use;
4) Putting the PAN membrane in the step 2) into the NaOH solution in the step 3) for hydrolysis, taking out the PAN membrane after 1 hour, and washing the PAN membrane with a large amount of deionized water until the surface is electrically neutral to obtain a Hydrolyzed Polyacrylonitrile (HPAN) support membrane;
5) 1.1g of cobalt nitrate hexahydrate (Co (NO) was weighed 3 ) 2 ) Adding 300g deionized water, stirring to dissolve completely, and diluting by 40 times to obtain Co (NO) 3 ) 2 A solution;
6) Weighing 0.25g of branched Polyethyleneimine (PEI) aqueous solution with the molecular weight of 60000 into a 250mL volumetric flask, and adding deionized water to prepare a PEI solution with the concentration of 1 g/L;
7) Weighing 5.2g of 2-methylimidazole (Hmim), adding 20mL of PEI solution, performing ultrasonic treatment until the solution is completely dissolved, and diluting the solution by 40 times by using the PEI solution to obtain a Hmim/PEI mixed solution
8) Soaking the HPAN support film obtained in the step 4) in Co (NO) 3 ) 2 In solution, after 5 hours it was removed and the membrane surface rinsed with copious amounts of deionized water until free of Co (NO) 3 ) 2 Solution residue;
9) Pouring 20mL of an Hmim/PEI mixed solution onto the HPAN supporting membrane obtained in the step 8), reacting for 30min, pouring out a PEI solution, and washing away the PEI solution remained on the HPAN supporting membrane by deionized water to obtain a ZIF-67-PEI/HPAN membrane;
10 30g of glycerol is weighed, 270g of deionized water is added, and a glycerol solution with the mass concentration fraction of 10% is obtained after uniform stirring;
11 Soaking the ZIF-67-PEI/HPAN membrane in a glycerol solution, taking out after 30min, directly putting into an oven at the temperature of 80 ℃, and taking out after 10min to obtain the final ZIF-67-PEI/HPAN positively charged mixed matrix composite nanofiltration membrane.
The retention rate of the composite membrane prepared in the example on PEG200 solution with the concentration of 0.1g/L is 93.2%, and the membrane flux is 34.9L/(m) 2 H.bar) against NaCl and MgSO 4 The retention rate of the composite is only 16.8 percent and 6.2 percent, and the high selectivity of the composite for retaining small-molecular organic matters and inorganic salts is shown.
Example 3
1) Weighing 9.6g of Polyacrylonitrile (PAN) as a solute, adding the solute into 50.4g of N, N-dimethylacetamide (DMAc), continuously stirring at the constant temperature of 80 ℃ until the PAN is completely dissolved, and standing and defoaming to obtain a casting solution;
2) Pouring the membrane casting solution on a non-woven fabric, scraping the membrane casting solution into a membrane with the thickness of 200 mu m, and quickly placing the membrane casting solution in deionized water for forming until the solvent is completely exchanged to obtain a PAN membrane;
3) Weighing 100g of sodium hydroxide (NaOH) and adding the sodium hydroxide into 900g of deionized water, continuously stirring until the NaOH is completely dissolved, and heating the solution to 50 ℃ for later use;
4) Putting the PAN membrane in the step 2) into the NaOH solution in the step 3) for hydrolysis, taking out the PAN membrane after 1 hour, and washing the PAN membrane with a large amount of deionized water until the surface is electrically neutral to obtain a Hydrolyzed Polyacrylonitrile (HPAN) support membrane;
5) 1.1g of cobalt nitrate hexahydrate (Co (NO) was weighed 3 ) 2 ) Adding 300g of deionized water, stirring until the mixture is completely dissolved, and diluting by 10 times to obtain Co (NO) 3 ) 2 A solution;
6) Weighing 0.25g of branched Polyethyleneimine (PEI) aqueous solution with the molecular weight of 60000 into a 250mL volumetric flask, and adding deionized water to prepare PEI solution with the concentration of 1 g/L;
7) Weighing 5.2g of 2-methylimidazole (Hmim), adding 20mL of the PEI solution obtained in the step 6), and diluting the PEI solution by 10 times by using the PEI solution after the PEI solution is completely dissolved to obtain a Hmim/PEI mixed solution;
8) Soaking the HPAN support film obtained in the step 4) in Co (NO) 3 ) 2 In solution, after 5 hours, it was removed and the membrane surface rinsed with copious amounts of deionized water until free of Co (NO) 3 ) 2 Solution residue;
9) Pouring 20mL of an Hmim/PEI mixed solution onto the HPAN supporting membrane obtained in the step 8), reacting for 30min, pouring out a PEI solution, and washing away the PEI solution remained on the HPAN supporting membrane by deionized water to obtain a ZIF-67-PEI/HPAN membrane;
10 30g of glycerol is weighed, 270g of deionized water is added, and a glycerol solution with the mass concentration fraction of 10% is obtained after uniform stirring;
11 Soaking the ZIF-67-PEI/HPAN membrane in a glycerol solution, taking out after 30min, directly putting into a drying oven with the temperature of 120 ℃, and taking out after 10min to obtain the final ZIF-67-PEI/HPAN positively charged mixed matrix composite nanofiltration membrane.
The retention rate of the composite membrane prepared in the example to the PEG200 solution with the concentration of 0.1g/L is 89.4%, and the membrane flux is 36.5L/(m) 2 ·h·bar)。
Example 4
1) Weighing 9.6g of Polyacrylonitrile (PAN) as a solute, adding the solute into 50.4g of N, N-dimethylacetamide (DMAc), continuously stirring at the constant temperature of 80 ℃ until the PAN is completely dissolved, and standing and defoaming to obtain a casting solution;
2) Pouring the membrane casting solution on a non-woven fabric, scraping the membrane casting solution into a membrane with the thickness of 200 mu m, and quickly placing the membrane casting solution in deionized water for forming until the solvent is completely exchanged to obtain a PAN membrane;
3) Weighing 100g of sodium hydroxide (NaOH) and adding the sodium hydroxide into 900g of deionized water, continuously stirring until the NaOH is completely dissolved, and heating the solution to 50 ℃ for later use;
4) Putting the PAN membrane in the step 2) into the NaOH solution in the step 3) for hydrolysis, taking out the PAN membrane after 1 hour, and washing the PAN membrane with a large amount of deionized water until the surface is electrically neutral to obtain a Hydrolyzed Polyacrylonitrile (HPAN) support membrane;
5) 1.1g of cobalt nitrate hexahydrate (Co (NO) was weighed 3 ) 2 ) Adding 300g of deionized water, stirring until the mixture is completely dissolved, and diluting by 40 times to obtain Co (NO) 3 ) 2 A solution;
6) Weighing 0.25g of linear Polyethyleneimine (PEI) with the molecular weight of 70000 into a 250mL volumetric flask, and adding deionized water to prepare a PEI solution with the concentration of 1 g/L;
7) Weighing 5.2g of 2-methylimidazole (Hmim), adding 20mL of the PEI solution obtained in step 6), and diluting the PEI solution by 40 times by using the PEI solution after the PEI solution is completely dissolved to obtain a Hmim/PEI mixed solution
8) Soaking the HPAN support film obtained in the step 4) in Co (NO) 3 ) 2 In solution, after 5 hours it was removed and the membrane surface rinsed with copious amounts of deionized water until free of Co (NO) 3 ) 2 Solution residue;
9) Pouring 20mL of the Hmim/PEI mixed solution onto the HPAN support membrane obtained in the step 8), reacting for 30min, pouring out the PEI solution, and washing away the PEI solution remained on the HPAN support membrane by using deionized water to obtain a ZIF-67-PEI/HPAN membrane;
10 30g of glycerol is weighed, 270g of deionized water is added, and a glycerol solution with the mass concentration fraction of 10% is obtained after uniform stirring;
11 Soaking the ZIF-67-PEI/HPAN membrane in a glycerol solution, taking out after 30min, directly putting into a drying oven with the temperature of 120 ℃, and taking out after 10min to obtain the final ZIF-67-PEI/HPAN positively charged mixed matrix composite nanofiltration membrane.
The retention rate of the composite membrane prepared in the example on PEG200 solution with the concentration of 0.1g/L is 91.9%, and the membrane flux is 29.6L/(m) 2 ·h·bar)。
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. A preparation method of a ZIFs mixed matrix composite nanofiltration membrane is characterized by comprising the following preparation steps:
1) Preparing a functional support film:
which comprises the following steps:
1a) Dissolving polyacrylonitrile in a first organic solvent, standing and defoaming to obtain a membrane casting solution;
1b) Coating the membrane casting solution obtained in the step 1 a) on non-woven fabrics in a scraping way, preparing a polymer support membrane by a non-solvent induced phase inversion method, soaking the polymer support membrane in NaOH solution, taking out the polymer support membrane, and washing the surface of the membrane by deionized water until the washing water is neutral to obtain a functional support membrane;
alternatively, it comprises the steps of:
1c) Blending the water-insoluble polymer with negative charges into a second organic solvent of the main polymer, and then preparing the functionalized support membrane by a phase inversion method;
2) Soaking in a metal salt solution:
soaking the functionalized support membrane obtained in the step 1) in a metal salt solution, taking out the functionalized support membrane, and washing the surface of the membrane with deionized water;
3) Surface reactions to produce selective separation layers and ZIFs:
preparing a mixed solution of polycation electrolyte and 2-methylimidazole, pouring the mixed solution on the surface of the functionalized support membrane prepared in the step 2), standing, reacting, and washing the surface of the membrane with deionized water to remove unreacted substances;
4) And (3) post-treatment:
performing glycerin soaking and high-temperature drying post-treatment on the membrane obtained in the step 3) to finally obtain a mixed matrix composite nanofiltration membrane;
the first organic solvent is N, N-dimethylacetamide, N-dimethylformamide, N-methylpyrrolidone or dimethyl sulfoxide;
the main polymer is selected from any one of polyether sulfone, polysulfone or polyphenol;
the water-insoluble polymer with negative charge is selected from any one of sulfonated polyether ether ketone, styrene-maleic anhydride copolymer or carboxylated polysulfone;
the second organic solvent is N, N-dimethylacetamide, N-dimethylformamide, N-methylpyrrolidone or dimethyl sulfoxide;
the metal salt solution is one of zinc nitrate or cobalt nitrate;
the polycation electrolyte is one of polyethyleneimine, polydiallyldimethylammonium chloride or dopamine.
2. The preparation method of the ZIFs mixed matrix composite nanofiltration membrane according to claim 1, wherein the preparation method comprises the following steps:
in the step 1 a), the mass percent of solute in the casting solution is 14-25%;
in the step 1 b), the mass concentration of the NaOH solution is 2-15%; the solvent of the NaOH solution is water, methanol or ethanol; the soaking treatment temperature is 20-60 deg.C, and the treatment time is 1-60min.
3. The preparation method of the ZIFs mixed matrix composite nanofiltration membrane according to claim 1, wherein the preparation method comprises the following steps: in the step 2), the mass concentration range of the metal salt solution is 0.1-3%, and the soaking time is 1-12h.
4. The preparation method of the ZIFs mixed matrix composite nanofiltration membrane according to claim 1, wherein in the step 3):
the mass concentration range of the polycation electrolyte is 0.1-0.5%, the mass concentration range of the 2-methylimidazole is 0.1-3%, and the reaction time is 5-120min.
5. The preparation method of the ZIFs mixed matrix composite nanofiltration membrane according to any one of claims 1 to 4, wherein in the step 4):
the mass concentration of the glycerol solution is 5-15%, and the soaking time is 5-60min;
the high temperature treatment temperature is 60-120 deg.C, and the time is 5-20min.
6. A ZIFs mixed matrix composite nanofiltration membrane prepared by the preparation method according to any one of claims 1 to 5.
7. The ZIFs mixed matrix composite nanofiltration membrane according to claim 6, wherein: the range of the molecular weight cut-off is 200-400Da.
8. Use of a ZIFs mixed matrix composite nanofiltration membrane according to claim 6 or 7, wherein: the nano-filtration membrane is used as a high-flux selective nano-filtration membrane.
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| CN104772046B (en) * | 2015-04-09 | 2017-09-26 | 中国科学院宁波材料技术与工程研究所 | The film preparations of zeolite imidazole metalloid organic frame ZIF 8 and the application in desalinization |
| CN106823854A (en) * | 2017-02-28 | 2017-06-13 | 北京工业大学 | A kind of preparation method of polymer-based metal organic backbone hybridized film |
| EP3560587A1 (en) * | 2018-04-24 | 2019-10-30 | Ecole Polytechnique Fédérale de Lausanne (EPFL) | Method for synthesis of a metal organic framework composite |
| US11135565B2 (en) * | 2018-10-25 | 2021-10-05 | Uti Limited Partnership | Metal organic framework (MOF) composite materials, methods, and uses thereof |
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