CN107670512B - Polyvinylidene fluoride hollow fiber membrane and preparation method thereof - Google Patents
Polyvinylidene fluoride hollow fiber membrane and preparation method thereof Download PDFInfo
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- CN107670512B CN107670512B CN201710958572.4A CN201710958572A CN107670512B CN 107670512 B CN107670512 B CN 107670512B CN 201710958572 A CN201710958572 A CN 201710958572A CN 107670512 B CN107670512 B CN 107670512B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/30—Polyalkenyl halides
- B01D71/32—Polyalkenyl halides containing fluorine atoms
- B01D71/34—Polyvinylidene fluoride
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/08—Hollow fibre membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/36—Hydrophilic membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/48—Antimicrobial properties
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Abstract
The invention discloses a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof, wherein a composite material of titanium dioxide and chitosan is prepared by adopting a surface deposition crosslinking method, then the composite material is doped into a membrane casting solution, and is extruded together with a core solution through a spinning nozzle and mixed in an air gap, and then the composite material is subjected to coagulation bath and blending modification to prepare the polyvinylidene fluoride hollow fiber membrane with hydrophilicity and antibacterial property. The titanium dioxide and the chitosan are prepared into the composite material, so that the agglomeration of the titanium dioxide can be inhibited, and the loss of the chitosan can be prevented; the prepared polyvinylidene fluoride hollow fiber membrane integrates hydrophilicity and antibacterial property, and has good application prospect.
Description
Technical Field
The invention relates to a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof.
Background
Polyvinylidene fluoride is widely applied to the field of membrane separation due to the advantages of excellent thermal stability, corrosion resistance, oxidation resistance and the like, and is one of the most common membrane materials at present. However, the hydrophilic property and biocompatibility of the membrane are poor, and the membrane separation performance is gradually reduced due to the fact that the membrane is easily adsorbed with pollutants such as grease and protein or polluted by microorganism and bacteria in a water body in the process of treating an aqueous solution, the service life of the membrane is also adversely affected by frequent chemical or physical cleaning, and the cleaning and maintenance cost of the membrane is also increased.
The current membrane modification mainly comprises surface modification and blending modification. The surface modification mainly comprises two methods, namely coating and grafting, which can cause the modifier to block the membrane pores, so that the membrane pore size and porosity are reduced, and the water yield is finally influenced. The blending modification can avoid the problem, and the doped water-insoluble modifier can not run off in the process of preparing a film or treating an aqueous solution.
Disclosure of Invention
The invention aims to provide a preparation method of a polyvinylidene fluoride hollow fiber membrane.
In order to achieve the purpose, the invention adopts the technical scheme that:
a preparation method of a polyvinylidene fluoride hollow fiber membrane comprises the following steps:
(1) ultrasonically dispersing titanium dioxide powder in deionized water, adding the deionized water into an acetic acid solution of chitosan, stirring and simultaneously adding ammonia water to deposit the chitosan on the titanium dioxide to obtain a first mixture;
(2) heating the first mixture to 40-70 ℃, adding a cross-linking agent glutaraldehyde, and continuing stirring to obtain a second mixture;
(3) washing the second mixture by dilute acetic acid, washing the second mixture by deionized water, and drying to obtain a composite material;
(4) grinding the composite material into powder, ultrasonically dispersing the powder in a first film-making solvent, sequentially adding polyvinylidene fluoride powder and a pore-forming agent, uniformly stirring to obtain a film casting solution, and carrying out vacuum standing and defoaming on the film casting solution;
(5) uniformly mixing a second film-making solvent and pure water to obtain a core solution;
(6) extruding the membrane casting solution and the core solution from a spinning nozzle, and mixing the membrane casting solution and the core solution through a section of air gap to obtain a nascent fiber;
(7) putting the nascent fiber into a first coagulating bath groove filled with ethanol solution;
(8) and putting the nascent fiber taken out of the first coagulation bath tank into a second coagulation bath tank filled with pure water, and taking out to obtain the polyvinylidene fluoride hollow fiber membrane.
Preferably, in the step (1), in the acetic acid solution of chitosan, the mass fraction of the chitosan is 0.5% -2%, and the pH value of the acetic acid solution of chitosan is between 8 and 12.
Preferably, in the step (2), the concentration of the glutaraldehyde is 5% to 30%.
Preferably, in the step (4), the first membrane-making solvent with a mass fraction of 60% -80%, the polyvinylidene fluoride powder with a mass fraction of 15% -25%, the pore-forming agent with a mass fraction of 5% -15% and the composite material are mixed to prepare the membrane casting solution, wherein the mass fraction of the composite material is 0.5% -8% of the mass fraction of the polyvinylidene fluoride powder.
Preferably, in the step (4), the first film-forming solvent is composed of one or more of Dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), Dimethylsulfoxide (DMSO), and triethyl phosphate (TEP).
Preferably, in the step (5), the second film-forming solvent is composed of one or more of Dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), Dimethylsulfoxide (DMSO), and triethyl phosphate (TEP), and the concentration of the second film-forming solvent in the bore fluid is 5% to 30%.
Preferably, in step (6), the length of the air gap is between 5 and 20 cm.
Preferably, in the step (7), the concentration of ethanol is 10% -60%.
Another object of the present invention is to provide a polyvinylidene fluoride hollow fiber membrane having both hydrophilicity and antibacterial property, which is manufactured by the above manufacturing method.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages: the invention relates to a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof. The titanium dioxide and the chitosan are prepared into the composite material, so that the agglomeration of the titanium dioxide can be inhibited, and the loss of the chitosan can be prevented; the prepared polyvinylidene fluoride hollow fiber membrane integrates hydrophilicity and antibacterial property, and has good application prospect.
Drawings
FIG. 1 is a graph of test data for example 1.
Detailed Description
The technical solution of the present invention is further explained below.
The preparation method of the polyvinylidene fluoride hollow fiber membrane comprises the following steps:
(1) ultrasonically dispersing titanium dioxide powder in deionized water, adding the deionized water into an acetic acid solution of chitosan, stirring and simultaneously adding ammonia water to deposit the chitosan on the titanium dioxide to obtain a first mixture; in the acetic acid solution of chitosan, the mass fraction of the chitosan is 0.5% -2%, and the pH value of the acetic acid solution of chitosan is between 8 and 12; the pH was adjusted by adding ammonia so that the chitosan could be more uniformly deposited on the titanium dioxide.
(2) Heating the first mixture to 40-70 ℃, adding a cross-linking agent glutaraldehyde, and continuing stirring for 2 hours to obtain a second mixture; wherein, the concentration of the glutaraldehyde is 5% -30%.
(3) Firstly, carrying out multiple centrifugal cleaning on the second mixture through dilute acetic acid to remove unreacted chitosan in the second mixture; then, washing the second mixture by deionized water to wash off residual dilute acetic acid on the second mixture; and (5) freeze-drying to obtain the composite material. The surface of the nano titanium dioxide (TiO2) is rich in hydroxyl, is a hydrophilic material and is easy to agglomerate; chitosan (CS) is a natural biopolymer, has good antibacterial property and biocompatibility, but is easily dissolved when meeting acidic solutions such as dilute acetic acid and benzoic acid. The composite material prepared from the titanium dioxide and the chitosan can inhibit the agglomeration of the titanium dioxide and prevent the loss of the chitosan.
(4) Grinding the composite material into powder, ultrasonically dispersing the powder in a first film-making solvent with the mass fraction of 60-80%, sequentially adding 15-25% of polyvinylidene fluoride powder and 5-15% of pore-forming agent, uniformly stirring for 6-12h to obtain a film casting solution, and carrying out vacuum standing and defoaming on the film casting solution for 12-24 h; wherein the mass of the composite material is 0.5-8% of that of the polyvinylidene fluoride powder;
the first membrane-forming solvent is composed of one or more of Dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO) and triethyl phosphate (TEP).
(5) Uniformly mixing a second film-making solvent and pure water to obtain a core solution;
the second film-making solvent is composed of one or more of Dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO) and triethyl phosphate (TEP), and the concentration of the second film-making solvent in the core solution is 5-30%.
(6) Extruding the casting solution at the temperature of 60-95 ℃ and the core solution at the temperature of 30-65 ℃ from a spinning nozzle, and mixing through a section of air gap to obtain nascent fiber; the length of the air gap is between 5 and 20 cm;
the core liquid is driven by a peristaltic pump, and the flow rate is 15-30 ml/min; the casting solution is driven by a metering pump, and the flow rate is 10-20 ml/min.
(7) Putting the nascent fiber into a first coagulating bath groove filled with ethanol solution; wherein, the concentration of the ethanol is 10 to 60 percent; the temperature of the first coagulation bath is between 30 and 70 ℃.
(8) Taking out the nascent-state fiber from the first coagulating bath tank, putting the nascent-state fiber into a second coagulating bath tank filled with pure water, and taking out the nascent-state fiber to obtain a polyvinylidene fluoride hollow fiber membrane; the temperature of the second coagulation bath is between 30 and 70 ℃.
The polyvinylidene fluoride hollow fiber membrane prepared by the preparation method integrates hydrophilicity and antibacterial property, and has a good application prospect.
Example 1
In the step (4), the mass ratios of the composite material to the polyvinylidene fluoride powder are adjusted to 0%, 0.5%, 1%, 2%, 4%, and 8%, respectively. 6 parts of different polyvinylidene fluoride hollow fiber membranes are prepared, and pure water flux of the polyvinylidene fluoride hollow fiber membranes is respectively tested at the temperature of 25 ℃, and the test data are shown in a reference figure 1.
The result shows that the pure water flux of the polyvinylidene fluoride hollow fiber membrane is increased rapidly and then becomes gentle with the increase of the addition amount of the composite material, which shows that the hydrophilic property of the polyvinylidene fluoride hollow fiber membrane is improved by adding the composite material, so that the permeability of the polyvinylidene fluoride hollow fiber membrane is greatly improved.
Example 2
In the step (4), the mass ratios of the composite material to the polyvinylidene fluoride powder are adjusted to 0%, 0.5%, 1%, 2%, 4%, and 8%, respectively. 6 parts of different polyvinylidene fluoride hollow fiber membranes are prepared, the polyvinylidene fluoride hollow fiber membranes are soaked in an aqueous solution containing a certain amount of staphylococcus aureus strains, the pure water flux of the polyvinylidene fluoride hollow fiber membranes is measured after one week, the attenuation rate of the polyvinylidene fluoride hollow fiber membranes is calculated, and the results are shown in the following table.
The result shows that the pure water flux attenuation rate of the polyvinylidene fluoride hollow fiber membrane added with the composite material is obviously lower than that of the polyvinylidene fluoride hollow fiber membrane not added with the composite material, and the pure water flux attenuation rate is smaller with the increase of the addition amount of the composite material. The antibacterial property of the polyvinylidene fluoride hollow fiber membrane is improved by adding the composite material, so that the polyvinylidene fluoride hollow fiber membrane is not easily polluted by bacteria. The above-mentioned embodiments are merely illustrative of the technical idea and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered in the scope of the present invention.
Claims (6)
1. A preparation method of a polyvinylidene fluoride hollow fiber membrane is characterized by comprising the following steps: the method comprises the following steps:
(1) ultrasonically dispersing titanium dioxide powder in deionized water, adding the deionized water into an acetic acid solution of chitosan, stirring and simultaneously adding ammonia water to deposit the chitosan on the titanium dioxide to obtain a first mixture;
(2) heating the first mixture to 40-70 ℃, adding a cross-linking agent glutaraldehyde, and continuing stirring to obtain a second mixture;
(3) washing the second mixture by dilute acetic acid, washing the second mixture by deionized water, and drying to obtain a composite material;
(4) grinding the composite material into powder, ultrasonically dispersing the powder in a first film-making solvent, sequentially adding polyvinylidene fluoride powder and a pore-forming agent, uniformly stirring to obtain a film casting solution, and carrying out vacuum standing and defoaming on the film casting solution;
(5) uniformly mixing a second film-making solvent and pure water to obtain a core solution;
(6) extruding the membrane casting solution and the core solution from a spinning nozzle, and mixing the membrane casting solution and the core solution through a section of air gap to obtain a nascent fiber;
(7) putting the nascent fiber into a first coagulating bath groove filled with ethanol solution;
(8) putting the nascent fiber taken out of the first coagulation bath tank into a second coagulation bath tank filled with pure water, and taking out to obtain a polyvinylidene fluoride hollow fiber membrane;
in the step (1), in the acetic acid solution of chitosan, the mass fraction of the chitosan is 0.5% -2%, and the pH value of the acetic acid solution of chitosan is between 8 and 12;
in the step (2), the concentration of the glutaraldehyde is 5% -30%;
in the step (4), the first membrane-making solvent with the mass fraction of 60% -80%, the polyvinylidene fluoride powder with the mass fraction of 15% -25%, the pore-forming agent with the mass fraction of 5% -15% and the composite material are mixed to prepare the membrane casting solution, wherein the mass fraction of the composite material is 0.5% -8% of the mass fraction of the polyvinylidene fluoride powder.
2. The preparation method of a polyvinylidene fluoride hollow fiber membrane according to claim 1, characterized in that: in the step (4), the first film-forming solvent is composed of one or more of Dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), Dimethylsulfoxide (DMSO), and triethyl phosphate (TEP).
3. The preparation method of a polyvinylidene fluoride hollow fiber membrane according to claim 1, characterized in that: in the step (5), the second film-forming solvent is composed of one or more of Dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), and triethyl phosphate (TEP), and the concentration of the second film-forming solvent in the bore fluid is 5% to 30%.
4. The preparation method of a polyvinylidene fluoride hollow fiber membrane according to claim 1, characterized in that: in the step (6), the length of the air gap is between 5 and 20 cm.
5. The preparation method of a polyvinylidene fluoride hollow fiber membrane according to claim 1, characterized in that: in the step (7), the concentration of the ethanol is 10-60%.
6. Polyvinylidene fluoride hollow fiber membrane produced according to the production method of any one of claims 1 to 5.
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| CN111871221A (en) * | 2020-07-09 | 2020-11-03 | 天津科技大学 | Hydrophobic/hydrophilic composite membrane with nuclear track etching membrane as base membrane and preparation method and application thereof |
| CN114806045B (en) * | 2022-05-16 | 2023-06-30 | 山东招金膜天股份有限公司 | Modified master batch for preparing antibacterial polyvinylidene fluoride porous membrane and preparation method thereof |
| CN114806044B (en) * | 2022-05-16 | 2023-06-30 | 山东招金膜天股份有限公司 | Antibacterial polyvinylidene fluoride porous membrane and preparation method thereof |
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