CN115888413A - ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane as well as preparation method and application thereof - Google Patents

ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane as well as preparation method and application thereof Download PDF

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CN115888413A
CN115888413A CN202211458750.4A CN202211458750A CN115888413A CN 115888413 A CN115888413 A CN 115888413A CN 202211458750 A CN202211458750 A CN 202211458750A CN 115888413 A CN115888413 A CN 115888413A
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nanotube
membrane
zifs
ultrafiltration membrane
zif
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周宏伟
陈盼
戴江南
王帅
王大明
赵晓刚
陈春海
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Jilin University
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Abstract

The invention provides a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane as well as a preparation method and application thereof, belonging to the technical field of water treatment. According to the invention, the ZIFs particle loaded nanotube is used as a hydrophilic filler, a polymer matrix is subjected to blending modification, and water molecules in sewage and N atoms in the ZIFs particle loaded nanotube form hydrogen bonds; the electrostatic interaction and the hydrogen bond interaction between the ZIFs particle loaded nanotube and water molecules can form a hydration layer on the surface of the membrane, so that the hydrophilicity of the ultrafiltration membrane is increased. The hydration layer provides a barrier for the surface of the membrane, so that pollutant molecules are not easy to contact with the surface of the membrane, and the anti-pollution performance of the ultrafiltration membrane is improved. As the surface of the ZIFs particle loaded nanotube is positively charged, the repulsion between tubes is increased, and further, the ZIFs/NTs nanoparticles are well dispersed in the solution, the agglomeration is avoided, the surface layer of the ultrafiltration membrane is not easy to generate defects, and the permeability and the pollution resistance of the ultrafiltration membrane are improved.

Description

ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane as well as preparation method and application thereof
Technical Field
The invention relates to the technical field of water treatment, in particular to a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane and a preparation method and application thereof.
Background
Sustainable development of water resources is the key to modern society and economic development, and membrane separation, an emerging separation technology, has emerged in the beginning of the 20 th century and has grown up rapidly after the 60's of the 20 th century. With the rapid development of modern science and technology, people have deeper and deeper knowledge on separation technology and stricter requirements on separation technology. Nowadays, the variety of membrane separation technology is increasing day by day, the classification is more detailed, and the application field is also becoming wide. The ultrafiltration technology has the obvious advantages of unchanged phase state, no need of heating, simple equipment, small occupied area, low operation pressure, low energy consumption and the like, so that the research is quickly shifted to practical application, and the ultrafiltration technology is quickly applied in large scale in industry. However, in the practical application process, the particles, colloidal particles or solute macromolecules in the separation system are adsorbed and deposited on the surface or in the pores of the membrane, so that the membrane is polluted, the flux is reduced, and the service life of the membrane is shortened.
In order to obtain a high-flux, high-selectivity and pollution-resistant ultrafiltration membrane, more and more researchers introduce various types of hydrophilic polymers or nanoparticles which are uniformly and firmly distributed on the surface of the membrane through physicochemical action, and introduce new functional groups on the surface to increase the hydrophilicity of the surface of the membrane, wherein the hydrophilic surface is not only favorable for the permeation of water molecules, but also can form a hydration layer on the surface of the membrane to enhance the pollution resistance of the surface of the membrane. The specific modification method mainly comprises three types of bulk modification, blending modification and surface modification. Li Jian-Hua et al (J.H.Li, Y.Y.xu, L.P.Zhu, J.H.Wang, C.H.Du.F. contamination and characterization of novel TiO) 2 nanometer titanium dioxide dispersion liquid is prepared by controlling hydrolysis of titanium tetraisopropoxide, and the ultrahigh molecular weight polystyrene-maleic anhydride/polyvinylidene fluoride blended membrane prepared by the phase inversion method is soaked in the titanium dioxide nanometer particle dispersion liquid for seven days, so that the novel titanium dioxide nanometer particle self-assembled membrane is obtained. Arthaneasonaswaran et al (G. Arthaneasonaswaran, T.K.Sriyamuna Devi, M.Raajenthuren.Effect of silicon particles on cellulose acetate copolymers, part I.Sep.Purif. Technol.2008,64 (1): 38-47) use N, N-dimethylformamide as a polar solvent, add 10-40 wt.% of silica particles to the cellulose acetate polymer, and then prepare the organic-inorganic ultrafiltration membrane by a dip-precipitation phase inversion method. However, incompatibility between inorganic nanoparticles and polysulfone polymer can produce undesirable effects such as interfacial voids, particle egress, clogging of membrane pores by particles, etc.; due to the filler agglomeration phenomenon caused by strong surface tension and high surface energy, the inorganic nano particles are unevenly dispersed in the polymer matrix; the binding capacity between the inorganic particles and the membrane matrix is weaker, and the composite ultrafiltration membrane has poorer stability in application. Sofiah Hamzah et al (Sofiah Hamzah, nora' aini Ali, abdul Wahab Mohammad, marinah Mohd Ariffin and Asmadi Ali. Design of chitosan/PSf self-assembly membrane to delivery formulation and enhance performance in treatment section.J.Chem.Technol.Biotechnol.2011, 87 (8): 1157-1166) prepared three chitosan surface modified composite ultrafiltration membranes by varying the time of immersion of polysulfone membrane in the chitosan solution. However, the shorter immersion time causes uneven dispersion of chitosan on the surface of the membrane and agglomeration; longer dipping time, more chitosan is deposited on the surface and in the pores of the membrane; these reduce the hydrophilicity of the ultrafiltration membrane, thereby shortening the life of the membrane and reducing the anti-fouling properties of the membrane.
Metal organic framework Materials (MOFs) are a new type of nanomaterials that have been widely focused and studied by researchers in recent years. Zeolite-like metal organic framework materials (ZIFs) are one of MOFs, the coordination center ions of the ZIFs are mainly divalent metal zinc and metal cobalt, and the organic ligand coordinated with the metal center is imidazole or imidazole derivatives and has the characteristics of rigidity of inorganic materials and flexibility of organic materials. Currently, although MOF materials have been disclosed for water treatment, MOF materials are not hydrophilic and agglomerate and leach out of the polymer matrix, reducing the flux and anti-fouling properties of ultrafiltration membranes.
Disclosure of Invention
The invention aims to provide a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane, and a preparation method and application thereof.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane, which comprises the following steps:
mixing a zinc source, an imidazole compound, a nanotube and a first solvent, and carrying out a hydrothermal synthesis reaction to obtain a ZIFs particle loaded nanotube;
and mixing the ZIFs particle loaded nanotube, a polymer matrix and a second solvent, and paving the membrane of the obtained membrane casting solution to obtain the ZIFs particle loaded nanotube modified polymer matrix ultrafiltration membrane.
Preferably, the zinc source comprises zinc nitrate, zinc sulfate, zinc acetate, zinc chloride, zinc iodide or zinc acetylacetonate.
Preferably, the imidazole compounds include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-nitroimidazole, benzimidazole, 4, 5-dichloroimidazole, 5-chlorobenzimidazole, 5, 6-dimethylbenzimidazole, purine, imidazole-2-carbaldehyde, N-acetylimidazole, methylbenzotriazole, benzimidazole-5-carboxylic acid, N-benzoylimidazole, 2-mercaptoimidazole or 2-hydroxymethylbenzimidazole; the molar ratio of the zinc source to the imidazole compound is 1 (2-72).
Preferably, the nanotube is a carbon nanotube, a halloysite nanotube, a titanium dioxide nanotube, an alumina nanotube or a silicon dioxide nanotube; the outer diameter of the halloysite nanotube is 50-70 nm, the inner diameter is 15-30 nm, and the length is 0.5-1.5 mu m; the molar ratio of the zinc source to the nanotube is 1 (0.01-10).
Preferably, the hydrothermal synthesis reaction further comprises adding reaction auxiliary agents, wherein the reaction auxiliary agents comprise N-butylamine, N-hexylamine, polyvinylpyrrolidone, N, N-dimethyloctadecylamine, N, N-dimethylethylenediamine, N, N, N ', N ' -tetramethylethylenediamine and N, N, N ' -tetramethyl-1, 6-hexanediamine, diethanolamine, N-dimethylbutylamine, 1-bromopentane, 1-bromooctane, 1-bromohexadecane, bromocyclopentane, tetramethylsuccinonitrile, glutaronitrile, hexanenitrile or tetradeconitrile; the molar ratio of the zinc source to the reaction auxiliary agent is 1 (0-10).
Preferably, the first solvent is one or more of water, methanol, acetone, ethanol, dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, dioxane and methyl ethyl ketone; the temperature of the hydrothermal synthesis reaction is 80-120 ℃, and the time is 5-12 h.
Preferably, the casting solution further comprises a pore-foaming agent, wherein the pore-foaming agent is polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, hydrolyzed polyacrylamide, polyacrylic acid, polyvinyl alcohol, polyethylene oxide or polymaleic anhydride; the mass percentage of the pore-foaming agent in the membrane casting liquid is 0-8%; the mass percentage of the ZIFs particle loaded nanotube in the membrane casting solution is 0-5% and is not 0; the mass percentage of the polymer matrix in the membrane casting solution is 12-25%.
Preferably, the polymer matrix has a structure represented by formula 1:
Figure BDA0003954543210000031
in formula 1, n is 30-300 and n is an integer; r 1 Is composed of
Figure BDA0003954543210000032
Figure BDA0003954543210000041
R 2 Is composed of
Figure BDA0003954543210000042
Figure BDA0003954543210000043
The invention provides a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane prepared by the preparation method in the technical scheme, which comprises a polymer matrix membrane and a ZIFs particle loaded nanotube doped in the polymer matrix membrane.
The invention provides application of the ZIFs particle-loaded nanotube modified polymer-based ultrafiltration membrane in water treatment.
The invention loads ZIFs particles on a nanotube, wherein the ZIFs are metal ions Zn 2+ The porous material composed of the imidazole compound and the organic ligand has a square sodium structure, an ideal specific surface area, an ideal pore diameter and an adjustable porous structure; the nano tube has a typical one-dimensional nano tubular structure, and the outer surface of the nano tube contains (or can be increased by chemical modification) abundant polar hydroxyl, amino, carboxyl and other groups which can directly react with metal ions, so that the active surface of the nano tube which is not modified at all is favorable for carrying out coordination reaction with zinc ions, and the ZIFs particle loaded nano tube is obtained. Moreover, the nanotube has a short water delivery channel, so that the pure water flux of the modified composite ultrafiltration membrane can be improved, the ZIFs particles increase the porosity and the average pore diameter of the membrane, the hydrophilicity is improved, water molecules can be rapidly transmitted through the membrane, and the pure water flux of the ultrafiltration membrane can be improved.
According to the invention, ZIFs particle loaded nanotubes (ZIFs/NTs) are used as hydrophilic fillers, a polymer matrix is subjected to blending modification, and water molecules in sewage and N atoms in the ZIFs particle loaded nanotubes form hydrogen bonds; because some defects exist in the ZIFs crystal structure framework due to incomplete coordination of zinc ions and organic ligands, the ZIFs crystal is positively charged, and therefore the surface of the ZIFs particle-loaded nanotube is positively charged. The electrostatic interaction and the hydrogen bond interaction between the ZIFs particle-loaded nanotube and water molecules can form a hydration layer on the surface of the membrane, so that the hydrophilicity of the ultrafiltration membrane is increased. The hydration layer provides a barrier for the surface of the membrane, so that pollutant molecules are not easy to contact with the surface of the membrane, and the anti-pollution performance of the ultrafiltration membrane is improved. On the other hand, as the surface of the ZIFs particle loaded nanotube is positively charged, the repulsion between tubes is increased, so that the ZIFs/NTs nano particles are well dispersed in the solution, the agglomeration is avoided, the surface layer of the ultrafiltration membrane is not easy to generate defects, and the permeability and the pollution resistance of the ultrafiltration membrane are improved.
Drawings
FIG. 1 is a scanning electron micrograph of the surface of the ultrafiltration membrane prepared in examples 2, 4,5 and 6;
FIG. 2 is a scanning electron micrograph of a cross section of an ultrafiltration membrane prepared in example 2;
FIG. 3 is an XRD spectrum of ZIF-8, HNTs, ZIF-8/HNTs-0.2 prepared in example 1, ZIF-8/HNTs-0.3 prepared in example 2, and ZIF-8/HNTs-0.4 nanoparticles prepared in example 3;
FIG. 4 is an XPS spectrum of HNTs, ZIF-8/HNTs-0.3;
FIG. 5 is an XPS spectrum of O1s in ZIF-8/HNTs-0.3 nanoparticles prepared in example 2;
FIG. 6 is a graph showing the change in pure water flux, rejection rate, and flux recovery rate of the ultrafiltration membranes obtained in comparative examples 1 and 2 and examples 1 to 6;
FIG. 7 is a graph showing the change in pure water flux, rejection and flux recovery of the ultrafiltration membranes obtained in examples 7 to 13.
Detailed Description
The invention provides a preparation method of a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane, which comprises the following steps:
mixing a zinc source, an imidazole compound, a nanotube and a first solvent, and carrying out a hydrothermal synthesis reaction to obtain a ZIFs particle loaded nanotube;
and mixing the ZIFs particle loaded nanotube, a polymer matrix and a second solvent, and spreading the obtained membrane casting solution to obtain the ZIFs particle loaded nanotube modified polymer matrix ultrafiltration membrane.
In the present invention, unless otherwise specified, all the starting materials or reagents required for the preparation are commercially available products well known to those skilled in the art.
According to the invention, a zinc source, an imidazole compound, a nanotube and a first solvent are mixed to carry out a hydrothermal synthesis reaction, so as to obtain the ZIFs particle loaded nanotube.
In the present invention, the zinc source preferably includes zinc nitrate, zinc sulfate, zinc acetate, zinc chloride, zinc iodide or zinc acetylacetonate, and the zinc source preferably is Zn (NO) 3 ) 2 ·6H 2 O、ZnSO 4 ·6H 2 O、 Zn(CH3COO) 2 ·2H 2 O、Zn(acac) 2 ·H 2 O、ZnCl 2 ·H 2 O、ZnI 2 ·H 2 O or its corresponding anhydrous salt.
In the present invention, the imidazole compounds preferably include
Figure BDA0003954543210000061
/>
Figure BDA0003954543210000062
Figure BDA0003954543210000071
In the present invention, the molar ratio of the zinc source to the imidazole compound is preferably 1 (2 to 72), more preferably 1.
In the present invention, the nanotubes are preferably carbon nanotubes, halloysite Nanotubes (HNTs), titanium dioxide nanotubes, alumina nanotubes or silica nanotubes; the preferred outer diameter of the halloysite nanotube is 50-70 nm, the preferred inner diameter is 15-30 nm, and the preferred length is 0.5-1.5 mu m; the molar ratio of the zinc source to the nanotubes is preferably 1 (0.01 to 10), more preferably 1 (0.2 to 1.5), and still more preferably 1 (0.3 to 0.88).
In the invention, in the hydrothermal synthesis reaction, a reaction auxiliary agent is preferably added, and the reaction auxiliary agent preferably comprises N-butylamine, N-hexylamine, polyvinylpyrrolidone and N, N-dimethyloctadecylamine, N, N-dimethylethylenediamine, N, N, N ', N' -tetramethylethylenediamine, N, N, N ', N' -tetramethyl-1, 6-hexanediamine, diethanolamine, N-dimethylbutylamine, 1-bromopentane, 1-bromooctane, 1-bromohexadecane, bromocyclopentane, tetramethylsuccinonitrile, glutaronitrile, hexanenitrile or tetradeconitrile, more preferably N-butylamine, N-hexylamine or diethanolamine; the molar ratio of the zinc source to the reaction auxiliary agent is preferably 1 (0-10), more preferably 1. The reaction rate of the hydrothermal synthesis reaction can be improved by using the reaction auxiliary agent.
In the invention, the first solvent is preferably one or more of water, methanol, acetone, ethanol, dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, dioxane and methyl ethyl ketone; when the first solvent is two of the above solvents, the volume ratio of the two solvents is preferably 1 (0.01-5), more preferably 1 (0.5-1).
In the invention, preferably, the process of mixing the zinc source, the imidazole compound, the nanotube, the reaction auxiliary agent and the first solvent is to add the zinc source into a part of the first solvent, perform first magnetic stirring to obtain a solution 1, add the imidazole compound and the nanotube into the rest of the first solvent, perform second magnetic stirring after ultrasonic dispersion to obtain a dispersion liquid 2; pouring the solution 1 and the dispersion liquid 2 into a reaction kettle, and adding a reaction auxiliary agent; the concentration of the solution 1 is preferably 0 to 20g/L and is not 0, more preferably 7.32 to 10.00g/L, and still more preferably 9.92g/L; the concentration of the dispersion 2 is preferably 0 to 30g/L and is not 0, more preferably 12.08 to 15.81g/L, and still more preferably 13.81g/L; the time of the first magnetic stirring is preferably 5min; the time of ultrasonic dispersion is preferably 30-120 min, and more preferably 40-80 min; the time of the second magnetic stirring is preferably 0 to 60min, and more preferably 5 to 30min. The stirring speed is not specially limited, and the stirring speed can be adjusted according to actual requirements.
In the invention, the temperature of the hydrothermal synthesis reaction is preferably 80-120 ℃, and more preferably 90-110 ℃; the time is preferably 5 to 12 hours, more preferably 6 hours; in the hydrothermal synthesis reaction process, 2-methylimidazole and the nanotube lose protons under the action of a solvent and heat to form an active center, and then coordinate and complex with zinc ions to form a crystal nucleus.
After the hydrothermal synthesis reaction is completed, the obtained reaction liquid is preferably centrifuged, supernatant liquid is poured off, white precipitate is washed by methanol, the centrifuging and washing processes are repeated for 3 to 5 times, and the obtained product is dried for 8 to 12 hours to constant weight at 80 to 100 ℃ (more preferably 90 ℃) under the condition of-0.8 to-1.0 MPa (more preferably-0.9 MPa) of a vacuum oven to obtain the ZIFs particle loaded nanotube which is recorded as ZIFs/NTs. And (ZIFs/NTs) -N is recorded according to the adding amount of the nanotube, wherein N is the molar ratio of the nanotube to zinc ions. The present invention is not particularly limited to the specific procedures of the centrifugation and the methanol washing, and may be carried out according to procedures well known in the art.
In the ZIFs particle loaded nanotube, a hydroxyl group on the nanotube is coordinated with zinc ions to generate a Zn-O bond.
After the ZIFs particle-loaded nanotube is obtained, the ZIFs particle-loaded nanotube, a polymer matrix and a second solvent are mixed, and the obtained membrane casting solution is subjected to membrane paving to obtain the ZIFs particle-loaded nanotube modified polymer-based ultrafiltration membrane.
In the invention, the casting solution further comprises a pore-foaming agent, wherein the pore-foaming agent is preferably polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, hydrolyzed polyacrylamide, polyacrylic acid, polyvinyl alcohol, polyethylene oxide or polymaleic anhydride; the mass percentage content of the pore-forming agent in the membrane casting solution is preferably 0 to 8%, more preferably 2 to 6%, and even more preferably 4%. In the invention, as the pore-forming agent is dissolved in the non-solvent water in the process of film-forming phase inversion, a channel for the non-solvent to enter is formed, the non-solvent water and the second solvent are quickly exchanged to form membrane pores, the aperture ratio of the ultrafiltration membrane is improved, and the permeation flux is further improved.
In the present invention, the polymer matrix preferably has a structure represented by formula 1:
Figure BDA0003954543210000081
/>
in formula 1, n is 30-300 and n is an integer; r is 1 Is composed of
Figure BDA0003954543210000091
Figure BDA0003954543210000092
R 2 Is composed of
Figure BDA0003954543210000093
Figure BDA0003954543210000094
In the present invention, the polymer matrix is preferably:
Figure BDA0003954543210000095
/>
Figure BDA0003954543210000101
wherein n is 30 to 300 and n is an integer.
The source of the polymer matrix is not particularly limited in the present invention, and may be commercially available or prepared according to methods well known in the art.
The polymer matrix used in the invention is thermoplastic engineering plastic, such as polysulfone, polyethersulfone, polyetherketone or polyetherimide, has high mechanical strength, chemical stability and thermal stability, can resist corrosion of common acid, alkali and solvent, has high heat resistance level and good film forming performance.
In the invention, the second solvent is preferably one or more of N, N-dimethylacetamide, N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide and sulfolane; when the second solvent is more than two of the above, the ratio of the second solvents of different types is not particularly limited, and any ratio can be used.
In the invention, the mass percentage content of the ZIFs particle-loaded nanotube in the casting solution is preferably 0 to 5%, and is not 0, more preferably 0.5 to 3%, and even more preferably 1 to 2%; the mass percentage content of the polymer matrix in the casting solution is preferably 12-25%, and more preferably 13.5-20%.
In the invention, when the membrane casting solution comprises a pore-foaming agent, the mixing process of the ZIFs particle loaded nanotube, the polymer matrix, the second solvent and the pore-foaming agent is preferably to add the ZIFs particle loaded nanotube into the second solvent, perform ultrasonic treatment until the mixture is uniformly dispersed, add the pore-foaming agent, add the polymer matrix after complete dissolution, perform magnetic stirring, and perform vacuum deaeration to obtain the membrane casting solution; the temperature of the magnetic stirring is preferably 50-80 ℃, and more preferably 60-70 ℃; the time is preferably 8 to 12 hours, more preferably 10 to 11 hours. And when the membrane casting solution does not contain the pore-foaming agent, removing the pore-foaming agent in the mixing process. The process of ultrasonic dispersion and vacuum defoamation is not particularly limited in the present invention, and can be performed according to processes well known in the art.
In the invention, the film laying process preferably comprises pouring the casting solution on a clean substrate, and immediately scraping the casting solution into a film by a scraper at 25 ℃; standing the obtained substrate in air, and then immersing the substrate into ultrapure water to form a primary solid film; continuously immersing the nascent solid membrane in ultrapure water for 24h, and replacing water every 6h to obtain a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane; the gap of the scraper is preferably 50-200 μm, and more preferably 100 μm; the time for the standing in the air is preferably 15 to 40 seconds, more preferably 25 to 35 seconds, and further preferably 30 seconds. The substrate is not particularly limited in the present invention, and any corresponding substrate known in the art may be used.
The invention provides a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane prepared by the preparation method in the technical scheme, which comprises a polymer matrix membrane and a ZIFs particle loaded nanotube doped in the polymer matrix membrane. In the ultrafiltration membrane, the nano-tubes loaded by the ZIFs particles are positively charged, and an electrostatic interaction exists between the nano-tubes and a polymer matrix; and in the water treatment process, water molecules and N atoms in the ZIFs particle loaded nanotube form a hydrogen bond effect. The pore-foaming agent is loaded on the polymer matrix due to the fact that the nano tube is positively charged and has electrostatic interaction with the polymer matrix.
When the casting solution also includes a porogen, the porogen present on the membrane surface runs off in the coagulation bath, and the rest porogen adheres to the polymer matrix membrane.
The invention provides application of the ZIFs particle-loaded nanotube modified polymer-based ultrafiltration membrane in water treatment. The method of the present invention is not particularly limited, and the method may be applied according to a method known in the art.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the following examples, the polymer matrix used has the formula:
Figure BDA0003954543210000121
/>
Figure BDA0003954543210000131
wherein n is 30 to 300;
commercial brand number: PSF:25135-51-7; PPSU:25608-64-4; PES:9002-88-4.
PEK-C and PES-C are purchased from Heilongjiang Innovative materials, inc.; PES-COOH and PEK-COOH references (Preparation of hydrophilic and anti-inflammatory polymeric membrane derived from phenolic side polymerization method, zhixiao Liu, zhiming Mi, et al, applied Surface Science,2017,401, 69-78).
In the following examples, halloysite nanotubes having an outer diameter of 50 to 70nm, an inner diameter of 15 to 30nm and a length of 0.5 to 1.5 μm were used.
Example 1
(1) 0.2975g (1 mmol) of Zn (NO) 3 ) 2 ·6H 2 Adding O into a mixed solution of 15mL of methanol and 15mL of water, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.06g (0.2 mmol) of halloysite nanotube into a mixed solution of 15mL of methanol and 15mL of water, ultrasonically dispersing for 30min, and magnetically stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.3707g (5 mmol) of n-butylamine, and reacting for 5h at 90 ℃;
(4) Centrifuging the reaction liquid obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating centrifugation and washing for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain a ZIF-8 loaded halloysite nanotube (ZIF-8/HNTs-0.2);
(5) Adding 0.05g of ZIF-8/HNTs-0.2 into 8g of N, N-dimethylacetamide, performing ultrasonic treatment until the mixture is uniformly dispersed, adding 0.6g of polyvinylpyrrolidone, completely dissolving, adding 1.35g of PES-C (molecular weight is nine ten thousand), performing magnetic stirring at 80 ℃ for 10 hours, and performing vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in air for 30s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and changing water every 6h to obtain the ZIF-8 loaded halloysite nanotube modified ultrafiltration membrane.
Example 2
(1) 0.2975g (1 mmol) of Zn (NO) 3 ) 2 ·6H 2 Adding O into a mixed solution of 15mL of ethanol and 15mL of water, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.09g (0.3 mmol) of halloysite nanotube into a mixed solution of 15mL of ethanol and 15mL of water, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.5129g (5 mmol) of n-hexylamine, and reacting for 5h at 90 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain a ZIF-8 loaded halloysite nanotube (ZIF-8/HNTs-0.3);
(5) Adding 0.05g of ZIF-8/HNTs-0.3 into 8.4g of dimethylacetamide, performing ultrasonic treatment until the mixture is uniformly dispersed, adding 0.2g of polyvinylpyrrolidone, completely dissolving, adding 1.35g of PES-C (molecular weight is nine ten thousand), performing magnetic stirring at 70 ℃ for 11 hours, and performing vacuum defoaming to obtain a casting solution; the doping amount of the ZIF-8/HNTs-0.3 nano particles (the nano particles account for the ratio in the membrane casting solution) is 0.5 percent;
pouring the casting solution onto a clean substrate, and immediately scraping the substrate into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in air for 35s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and changing water every 6h to obtain the ZIF-8 loaded halloysite nanotube modified ultrafiltration membrane.
Example 3
(1) 0.2975g (1 mmol) of Zn (NO) 3 ) 2 ·6H 2 Adding O into 30mL of dimethyl sulfoxide, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.12g (0.4 mmol) of halloysite nanotube into 30mL of dimethyl sulfoxide solution, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.5129g (5 mmol) of n-hexylamine, and reacting for 6h at 80 ℃;
(4) Centrifuging the reaction liquid obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa at 90 ℃ for 12h to constant weight to obtain a ZIF-8 loaded halloysite nanotube (ZIF-8/HNTs-0.4);
(5) Adding 0.05g of ZIF-8/HNTs-0.4 into 4g of dimethylacetamide and 4g of N-methylpyrrolidone, carrying out ultrasonic treatment until the mixture is uniformly dispersed, adding 0.6g of polyvinyl alcohol, completely dissolving, adding 1.35g of PES-C (molecular weight is ninety thousand), carrying out magnetic stirring at 80 ℃ for 10 hours, and carrying out vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in air for 30s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and changing water every 6h to obtain the ZIF-8 loaded halloysite nanotube modified ultrafiltration membrane.
Example 4
(1) 0.2975g (1 mmol) of Zn (NO) 3 ) 2 ·6H 2 Adding O into 30mL of N, N-dimethylformamide, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.09g (0.3 mmol) of halloysite nanotube into a 30mLN N-dimethylformamide solution, ultrasonically dispersing for 30min, and magnetically stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.5329g (5 mmol) of diethanolamine, and reacting for 5h at 90 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain a ZIF-8 loaded halloysite nanotube (ZIF-8/HNTs-0.3);
(5) Adding 0.1g of ZIF-8/HNTs-0.3 into 8.15g of dimethylacetamide, carrying out ultrasonic treatment until the mixture is uniformly dispersed, adding 0.4g of polyvinylpyrrolidone, completely dissolving, adding 1.35g of PES-C (molecular weight is nine thousand), carrying out magnetic stirring at 80 ℃ for 10 hours, and carrying out vacuum defoaming to obtain a casting solution; the doping amount of the ZIF-8/HNTs-0.3 nano particles is 1.0 percent;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in air for 30s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and changing water every 6h to obtain the ZIF-8 loaded halloysite nanotube modified ultrafiltration membrane.
Example 5
(1) 0.2975g (1 mmol) of Zn (NO) 3 ) 2 ·6H 2 Adding O into 30mL of methanol, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.09g (0.3 mmol) of halloysite nanotubes into 30mL of methanol solution, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.5329g (5 mmol) of diethanolamine, and reacting for 5h at 90 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain a ZIF-8 loaded halloysite nanotube (ZIF-8/HNTs-0.3);
(5) Adding 0.15g of ZIF-8/HNTs-0.3 into 7.9g of dimethylacetamide, performing ultrasonic treatment until the mixture is uniformly dispersed, adding 0.6g of polyvinylpyrrolidone, completely dissolving, adding 1.35g of PES-C (molecular weight is nine ten thousand), performing magnetic stirring at 70 ℃ for 11 hours, and performing vacuum defoaming to obtain a casting solution; the doping amount of the ZIF-8/HNTs-0.3 nano particles is 1.5 percent;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in air for 35s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and changing water every 6h to obtain the ZIF-8 loaded halloysite nanotube modified ultrafiltration membrane.
Example 6
(1) 0.2975g (1 mmol) of Zn (NO) 3 ) 2 ·6H 2 Adding O into a mixed solution of 15mL of N, N-dimethylformamide and 15mL of water, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.09g (0.3 mmol) of halloysite nanotube into a mixed solution of 15mLN, N-dimethylformamide solution and 15mL of water, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.3707g (5 mmol) of n-butylamine, and reacting for 6h at 80 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain a ZIF-8 loaded halloysite nanotube (ZIF-8/HNTs-0.3);
(5) Adding 0.2g of ZIF-8/HNTs-0.3 into 7.65g of dimethylacetamide, carrying out ultrasonic treatment until the mixture is uniformly dispersed, adding 0.8g of polyvinylpyrrolidone, completely dissolving, adding 1.35g of PES-C (molecular weight is nine thousand), carrying out magnetic stirring at 60 ℃ for 12 hours, and carrying out vacuum defoaming to obtain a casting solution; the doping amount of the ZIF-8/HNTs-0.3 nano particles is 2 percent;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in the air for 30s, and then immersing the substrate in ultrapure water, wherein the primary film falls off from the substrate to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24 hours, and changing water every 6 hours to obtain the ZIF-8 loaded halloysite nanotube modified ultrafiltration membrane.
Example 7
(1) 0.2679g (1 mmol) of ZnSO 4 ·6H 2 Adding O into 30mL of ethanol, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.09g (0.3 mmol) of halloysite nanotubes into 30mL of ethanol solution, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, and reacting for 6h at 90 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain a ZIF-8 loaded halloysite nanotube (ZIF-8/HNTs-0.3);
(5) Adding 0.05g of ZIF-8/HNTs-0.3 into 8g of N-methylpyrrolidone, carrying out ultrasonic treatment until the mixture is uniformly dispersed, adding 0.6g of polyethylene glycol, completely dissolving, adding 1.35g of PES-COOH (with a molecular weight of nine ten thousand), carrying out magnetic stirring at 70 ℃ for 11 hours, and carrying out vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 150 mu m at 25 ℃; standing the substrate in air for 30s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and changing water every 6h to obtain the ZIF-8 loaded halloysite nanotube modified ultrafiltration membrane.
Example 8
(1) 0.2975g (1 mmol) of Zn (NO) 3 ) 2 ·6H 2 Adding O into a mixed solution of 15mL of methanol and 15mL of ethanol, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.2723g (4 mmol) of imidazole and 0.09g (0.88 mmol) of alumina nanotube into a mixed solution of 15mL of methanol and 15mL of ethanol, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.5329g (5 mmol) of diethanolamine, and reacting for 5h at 90 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, drying the obtained product in a vacuum oven at-0.9 MPa at 90 ℃ for 12h to constant weight to obtain ZIF-61 loaded alumina nanotube (ZIF-61/Al) 2 O 3 -0.88)；
(5) 0.05g of ZIF-61/Al 2 O 3 -0.88 to 8g dimethylacetamide, sonicated until dispersed uniformly, 0.6g polyethylene glycol added, dissolved completely and addedAdding 1.35g of PES (molecular weight: sixty thousand), magnetically stirring for 11h at 80 ℃, and defoaming in vacuum to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in the air for 25s, and then immersing the substrate in ultrapure water, wherein the primary film falls off from the substrate to form a primary solid film; and continuously immersing the primary solid membrane in ultrapure water for 24h, and replacing water every 6h to obtain the ZIF-61 loaded alumina nanotube modified ultrafiltration membrane.
Example 9
(1) 0.2816g (1 mmol) of Zn (acac) 2 ·H 2 Adding O into a mixed solution of 15mL of methanol and 15mL of water, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.09g (0.88 mmol) of alumina nanotube into a mixed solution of 15mL of methanol and 15mL of water, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.3707g (5 mmol) of n-butylamine, and reacting for 6h at 80 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain ZIF-8 loaded alumina nanotubes (ZIF-8/Al) 2 O 3 -0.88)；
(5) 0.05g of ZIF-8/Al 2 O 3 Adding-0.88 g of the mixture into 8g of N-methylpyrrolidone, performing ultrasonic treatment until the mixture is uniformly dispersed, adding 0.6g of polyethylene glycol, completely dissolving the mixture, adding 1.35g of PEK-COOH (molecular weight is ninety thousand), performing magnetic stirring at 80 ℃ for 10 hours, and performing vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 150 mu m at 25 ℃; standing the substrate in the air for 25s, and then immersing the substrate in ultrapure water, wherein the primary film falls off from the substrate to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24 hours, and replacing the water every 6 hours to obtain the ZIF-8 loaded alumina nanotube modified ultrafiltration membrane.
Example 10
(1) 0.2197g (1 mmol) of Zn (CH) 3 COO) 2 ·2H 2 Adding O into a mixed solution of 15mL of dimethyl sulfoxide and 15mL of water, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.09g (1.5 mmol) of silicon dioxide nanotube into a mixed solution of 15mL of dimethyl sulfoxide and 15mL of water, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.5129g (5 mmol) of n-hexylamine, and reacting for 5h at 90 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, drying the obtained product in a vacuum oven at-0.9 MPa at 90 ℃ for 12h to constant weight to obtain the ZIF-8 loaded silicon dioxide nanotube (ZIF-8/SiO) 2 -1.5)；
(5) 0.05g of ZIF-8/SiO 2 Adding-1.5 to 8g of N, N-dimethylformamide, performing ultrasonic treatment until the mixture is uniformly dispersed, adding 0.6g of polyvinyl alcohol, completely dissolving, adding 1.35g of PEK-C (molecular weight is nine thousand), performing magnetic stirring at 70 ℃ for 11 hours, and performing vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the substrate into a flat membrane by using a scraper with a gap of 200 mu m at 25 ℃; standing the substrate in the air for 35s, and then immersing the substrate in ultrapure water, wherein the primary film falls off from the substrate to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and replacing the water every 6h to obtain the ZIF-8 loaded silica nanotube modified ultrafiltration membrane.
Example 11
(1) 0.2679g (1 mmol) of ZnSO 4 ·6H 2 Adding O into 30mL of methanol, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.2723g (4 mmol) of imidazole and 0.09g (0.43 mmol) of carbon nanotube into 30mL of methanol, ultrasonically dispersing for 30min, and magnetically stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.5329g (5 mmol) of diethanolamine, and reacting for 5h at 90 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain a ZIF-61 loaded carbon nanotube (ZIF-61/CNTs-0.43);
(5) Adding 0.05g of ZIF-61/CNTs-0.43 into 8g of dimethylacetamide, performing ultrasonic treatment until the mixture is uniformly dispersed, adding 0.6g of polyvinylpyrrolidone, completely dissolving, adding 1.35g of PSF (molecular weight: eight ten thousand), performing magnetic stirring at 80 ℃ for 10 hours, and performing vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in the air for 30s, and then immersing the substrate in ultrapure water, wherein the primary film falls off from the substrate to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and replacing the water every 6h to obtain the ZIF-61 loaded carbon nanotube modified ultrafiltration membrane.
Example 12
(1) 0.2197g (1 mmol) of Zn (CH) 3 COO) 2 ·2H 2 Adding O into 30mL of ethanol, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3843g (4 mmol) of imidazole-2-formaldehyde and 0.09g (0.3 mmol) of halloysite nanotube into 30mL of ethanol solution, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.5329g (5 mmol) of diethanolamine, and reacting for 6h at 80 ℃;
(4) Centrifuging the reaction solution obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa and 90 ℃ for 12h to constant weight to obtain a ZIF-8 loaded halloysite nanotube (ZIF-90/HNTs-0.3);
(5) Adding 0.05g of ZIF-90/HNTs-0.3 into 8g of dimethylacetamide, performing ultrasonic treatment until the mixture is uniformly dispersed, adding 0.6g of polyvinylpyrrolidone, completely dissolving, adding 1.35g of PPSU (molecular weight: eighty thousand), performing magnetic stirring at 80 ℃ for 10 hours, and performing vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the substrate into a flat membrane by using a scraper with a gap of 150 mu m at 25 ℃; standing the substrate in the air for 30s, and then immersing the substrate in ultrapure water to ensure that the primary film falls off from the substrate to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and changing water every 6h to obtain the ZIF-90 loaded halloysite nanotube modified ultrafiltration membrane.
Example 13
(1) 0.2816g (1 mmol) of Zn (acac) 2 ·H 2 Adding O into 30mLN, N-dimethylformamide, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole and 0.09g (1.13 mmol) of titanium dioxide nanotube into a 30mLN N-dimethylformamide solution, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a reaction kettle with the specification of 100mL in sequence, adding 0.3707g (5 mmol) of n-butylamine, and reacting for 5h at 90 ℃;
(4) Centrifuging the reaction liquid obtained in the step (3), pouring out supernatant, washing white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, drying the obtained product in a vacuum oven at-0.9 MPa at 90 ℃ for 12h to constant weight to obtain ZIF-8 loaded titanium dioxide nanotubes (ZIF-8/TiO) 2 -1.13)；
(5) 0.05g of ZIF-8/TiO 2 Adding-1.13 to 8g of N-methylpyrrolidone, performing ultrasonic treatment until the dispersion is uniform, adding 0.6g of polyethylene glycol, completely dissolving, adding 1.35g of PES-COOH (molecular weight is nine thousand), performing magnetic stirring at 70 ℃ for 11 hours, and performing vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 150 mu m at 25 ℃; standing the substrate in air for 30s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the nascent solid membrane in ultrapure water for 24h, and replacing the water every 6h to obtain the ZIF-8 loaded titanium dioxide nanotube modified ultrafiltration membrane.
Comparative example 1
Adding 1.35g of PES-C (molecular weight is ninety thousand) into 8.05g of dimethylacetamide, performing ultrasonic treatment until the PES-C is uniformly dispersed, then adding 0.6g of polyvinylpyrrolidone, completely dissolving, adding the polyvinylpyrrolidone, performing magnetic stirring at 60 ℃ for 12 hours, and performing vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in air for 30s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the primary solid membrane in the ultrapure water for 24h, and replacing the water every 6h to obtain the polysulfone ultrafiltration membrane.
Comparative example 2
Adding 0.05g of halloysite nanotube HNTs into 8g of dimethylacetamide, performing ultrasonic treatment until the dispersion is uniform, then adding 0.6g of polyvinylpyrrolidone, completely dissolving, adding 1.35g of PES-C (molecular weight is nine ten thousand), performing magnetic stirring at 60 ℃ for 12h, and performing vacuum defoaming to obtain a casting solution;
pouring the casting solution onto a clean substrate, and immediately scraping the casting solution into a flat membrane by using a scraper with a gap of 100 mu m at 25 ℃; standing the substrate in air for 30s, and then immersing the substrate in ultrapure water to form a primary solid film; and continuously immersing the primary solid membrane in ultrapure water for 24h, and changing water every 6h to obtain the halloysite nanotube modified ultrafiltration membrane.
Comparative example 3
(1) 0.2975g (1 mmol) of Zn (NO) 3 ) 2 ·6H 2 Adding O into 30mL of methanol solution, and magnetically stirring for 5min to obtain a solution 1;
(2) Adding 0.3244g (4 mmol) of 2-methylimidazole into 30mL of methanol solution, performing ultrasonic dispersion for 30min, and performing magnetic stirring for 30min to obtain a dispersion liquid 2;
(3) Pouring the solution 1 and the dispersion liquid 2 into a 100mL reaction kettle in sequence, and reacting for 6h at 90 ℃;
(4) And (4) centrifuging the reaction solution obtained in the step (3), pouring out the supernatant, washing the white precipitate with methanol, repeating the centrifuging and washing processes for 4 times, and drying the obtained product in a vacuum oven at-0.9 MPa at 90 ℃ for 12h to constant weight to obtain the ZIF-8 nano particles.
Characterization and Performance testing
(1) SEM tests were performed on the ultrafiltration membranes prepared in examples 2, 4,5, and 6, and the results are shown in fig. 1 and 2; wherein, a, b, c and d are respectively surface scanning electron microscope micrographs of the ultrafiltration membranes obtained in the embodiments 2, 4,5 and 6; as can be seen from FIG. 1, tubular ZIF-8/HNTs nanoparticles exist on the surfaces of the ultrafiltration membranes prepared in examples 2, 4,5 and 6, and as the doping amount (the proportion of the nanoparticles in the membrane casting solution) of the ZIF-8/HNTs-0.3 nanoparticles is increased from 0.5wt% to 2wt%, more and more nanoparticles exist on the surfaces of the membranes and are uniformly dispersed. As can be seen from FIG. 2, the ultrafiltration membrane (1.5 wt%) prepared in example 5 exhibited a typical asymmetric structure, the membrane had a finger-like pore structure, and the membrane pores contained the doped tubular ZIF-8/HNTs-0.3 nanoparticles and were uniformly dispersed.
(2) FIG. 3 is an XRD spectrum of nanoparticles of halloysite nanotubes HNTs, ZIF-8/HNTs-0.2, ZIF-8/HNTs-0.3 and ZIF-8/HNTs-0.4 prepared in example 2. As can be seen from fig. 3, HNTs exhibit typical characteristic peaks at 2 θ =12.16 °, 19.86 °, 24.80 ° and 34.98 °, which are assigned to (001), (020,110), (002) and (200,130) lattice planes. ZIF-8 has a characteristic XRD pattern at 7.18 ° (011), 10.16 ° (002), 12.54 ° (112), 14.54 ° (022), 16.32 ° (013), 17.82 ° (222), 19.4 ° (123), 22.00 ° (114), 24.36 ° (223), 25.48 ° (224), 26.50 ° (015), 29.48 ° (044). In the XRD spectrogram of ZIF-8/HNTs nano particles with different halloysite nanotube contents, not only characteristic peaks of HNTs can be observed, but also characteristic peaks which are basically consistent with the XRD spectrogram of the original ZIF-8 exist, but the peak intensity is reduced, and the existence of ZIF-8 on halloysite nanotubes is proved. Therefore, ZIF-8/HNTs nano particles with different halloysite nano tube contents can be successfully prepared.
(3) FIG. 4 is an XPS spectrum of HNTs and ZIF-8/HNTs-0.3 nanoparticles prepared in example 2, as can be seen in FIG. 4: the ZIF-8/HNTs-0.3 nano particles contain C, N, O, si, al and Zn elements. FIG. 5 is an XPS spectrum of O1s of the ZIF-8/HNTs-0.3 nanoparticles in FIG. 4. From FIG. 5, it can be seen that in XPS of O1s, zn-O, zn-OH, si-O and Al-O bonds are respectively 530.66eV, 532.93eV, 532.3eV and 531.5eV, and the appearance of Zn-O bonds indicates that zinc ions are coordinated with hydroxyl groups on the surface of the halloysite nanotube, thereby proving that the ZIF-8 particles successfully load the halloysite nanotube.
(4) The ultrafiltration performance of the ZIF-8-loaded halloysite nanotube-modified ultrafiltration membranes prepared in examples 1 to 13 was examined as follows:
under the pressure of 0.15MPa, after the pure water is pre-pressed for 30min, the pressure is reduced to 0.1MPa, the flux value is recorded every 5min, the measurement is continued for 1h, and the last stable flux is recorded as J w1 (ii) a Replacing pure water with 1g/L bovine serum albumin solution, keeping the pressure of 0.1MPa constant, recording flux value every 5min, measuring for 1h, and recording the final stable flux J p (ii) a The contaminated membrane was then washed with pure water (ultrafiltration membrane in membrane tank was placed in reverse and washed with pure water for 1 h) and then passed through the washed membrane again with pure water at 0.1MPa, flux values were recorded every 5min, measurements were continued for 1h, and the final stable flux J was recorded w2 。
J is defined as the permeation flux per unit area of the membrane per unit time (L/m) 2 h) The calculation formula is as follows:
Figure BDA0003954543210000231
wherein V represents the permeation volume (L); a represents the membrane area (m) 2 ) (ii) a t represents the permeation time (h).
FRR is defined as the flux recovery, i.e. the degree to which the permeability of the membrane recovers to the point before fouling after the fouling-cleaning cycle, and is calculated as:
Figure BDA0003954543210000232
defining R as the retention rate of the bovine serum albumin solution, and measuring the concentration of the bovine serum albumin in the feed liquid and the penetrating fluid by using an ultraviolet-visible spectrophotometry, wherein the calculation formula is as follows:
Figure BDA0003954543210000233
wherein, C p Concentration of BSA in permeate (g/L), C f The concentration (g/L) of BSA contained in the raw material solution.
TABLE 1 pure water flux, rejection and flux recovery data for ultrafiltration membranes prepared in examples 1-13
Figure BDA0003954543210000234
Figure BDA0003954543210000241
Pure water flux, rejection rate and flux recovery rate change curves of the ultrafiltration membranes are plotted according to the data in table 1, as shown in fig. 6 and 7, fig. 6 is a pure water flux, rejection rate and flux recovery rate change curve of the ultrafiltration membranes obtained in comparative examples 1 and 2 and examples 1 to 6, and fig. 7 is a pure water flux, rejection rate and flux recovery rate change curve of the ultrafiltration membranes obtained in examples 7 to 13.
As is clear from Table 1 and FIG. 6, comparative example 1, i.e., the ultrafiltration membrane without any particle added, had the lowest pure water flux and flux recovery rate of 185L/m 2 h. 68.8 percent; comparative example 2, namely the pure water flux and flux recovery rate of the ultrafiltration membrane added with the halloysite nanotube are slightly higher and reach 286L/m 2 h. 70.1 percent. Respectively adding ZIF-8/HNTs-0.2, ZIF-8/HNTs-0.3 and ZIF-8/HNTs-0.4 nano particles, blending and modifying to obtain the ultrafiltration membrane, wherein the pure water flux is 406L/m along with the increase of the content of the halloysite nano tubes 2 h is gradually increased to 420L/m 2 h, the flux recovery increased from 73.8% to 75.6%. In examples 2, 4,5 and 6, different amounts of ZIF-8/HNTs-0.3 nanoparticles are respectively added to blend and modify the prepared ultrafiltration membrane, and the pure water flux is increased from 439L/m as the content of the ZIF-8/HNTs-0.3 nanoparticles is increased from 0.5 (w/v%) to 2 (w/v%) 2 h gradually increases to 482L/m 2 h, the flux recovery increased from 74.5% to 83.2%. After being modifiedThe retention rate of the ultrafiltration membrane to bovine serum albumin is reduced to some extent, but is more than 95%, and the ultrafiltration membrane still has good retention performance.
As can be seen from FIG. 7 and Table 1, the pure water flux of the composite ultrafiltration membrane prepared by blending nanotubes with different ZIFs loaded with different particles as fillers and polysulfone is 400L/m 2 h, the flux recovery rate is above 73%, and the retention rate of bovine serum albumin is above 95%. In example 11, the pure water flux of the composite ultrafiltration membrane prepared by blending the ZIF-61/CNTs-0.43 nano particles and polysulfone reaches the maximum, and is 461L/m 2 h, the flux recovery was also maximal at 80.7%.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A preparation method of a ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane is characterized by comprising the following steps of:
mixing a zinc source, an imidazole compound, a nanotube and a first solvent, and carrying out a hydrothermal synthesis reaction to obtain a ZIFs particle loaded nanotube;
and mixing the ZIFs particle loaded nanotube, a polymer matrix and a second solvent, and paving the membrane of the obtained membrane casting solution to obtain the ZIFs particle loaded nanotube modified polymer matrix ultrafiltration membrane.
2. The method of claim 1, wherein the zinc source comprises zinc nitrate, zinc sulfate, zinc acetate, zinc chloride, zinc iodide, or zinc acetylacetonate.
3. The method according to claim 1 or 2, wherein the imidazole compound comprises imidazole, 2-methylimidazole, 2-ethylimidazole, 2-nitroimidazole, benzimidazole, 4, 5-dichloroimidazole, 5-chlorobenzimidazole, 5, 6-dimethylbenzimidazole, purine, imidazole-2-carbaldehyde, N-acetylimidazole, methylbenzotriazole, benzimidazole-5-carboxylic acid, N-benzoylimidazole, 2-mercaptoimidazole or 2-hydroxymethylbenzimidazole; the molar ratio of the zinc source to the imidazole compound is 1 (2-72).
4. The production method according to claim 1 or 2, wherein the nanotube is a carbon nanotube, a halloysite nanotube, a titanium dioxide nanotube, an alumina nanotube, or a silica nanotube; the outer diameter of the halloysite nanotube is 50-70 nm, the inner diameter is 15-30 nm, and the length is 0.5-1.5 mu m; the molar ratio of the zinc source to the nanotube is 1 (0.01-10).
5. The preparation method according to claim 1 or 2, characterized in that the hydrothermal synthesis reaction further comprises adding a reaction auxiliary agent, wherein the reaction auxiliary agent comprises N-butylamine, N-hexylamine, polyvinylpyrrolidone, N-dimethyloctadecylamine, N-dimethylethylenediamine, N, N, N '-tetramethylethylenediamine, N' -tetramethyl-1, 6-hexanediamine, diethanolamine, N-dimethylbutylamine, 1-bromopentane, 1-bromooctane, 1-bromohexadecane, bromocyclopentane, tetramethylsuccinonitrile, glutaronitrile, hexanenitrile or tetradeconitrile; the molar ratio of the zinc source to the reaction auxiliary agent is 1 (0-10).
6. The method according to claim 1, wherein the first solvent is one or more selected from water, methanol, acetone, ethanol, dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, dioxane and methyl ethyl ketone; the temperature of the hydrothermal synthesis reaction is 80-120 ℃, and the time is 5-12 h.
7. The preparation method according to claim 1, wherein the casting solution further comprises a pore-foaming agent, and the pore-foaming agent is polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, hydrolyzed polyacrylamide, polyacrylic acid, polyvinyl alcohol, polyethylene oxide or polymaleic anhydride; the mass percentage of the pore-foaming agent in the membrane casting liquid is 0-8%; the mass percentage of the ZIFs particle loaded nanotube in the membrane casting solution is 0-5% and is not 0; the mass percentage of the polymer matrix in the membrane casting solution is 12-25%.
8. The method of claim 1 or 7, wherein the polymer matrix has a structure represented by formula 1:
Figure FDA0003954543200000021
in formula 1, n is 30-300 and n is an integer; r 1 Is composed of
Figure FDA0003954543200000022
/>
Figure FDA0003954543200000023
R 2 Is composed of
Figure FDA0003954543200000024
Figure FDA0003954543200000025
9. The ZIFs particle-loaded nanotube modified polymer-based ultrafiltration membrane prepared by the preparation method of any one of claims 1 to 8, which is characterized by comprising a polymer matrix membrane and ZIFs particle-loaded nanotubes doped in the polymer matrix membrane.
10. The use of the ZIFs particle-loaded nanotube-modified polymer-based ultrafiltration membrane of claim 9 in water treatment.
CN202211458750.4A 2022-11-17 2022-11-17 ZIFs particle loaded nanotube modified polymer-based ultrafiltration membrane as well as preparation method and application thereof Pending CN115888413A (en)

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