CN107551833B - A kind of pair of modified hollow fiber ultrafiltration membrane and preparation method thereof - Google Patents
A kind of pair of modified hollow fiber ultrafiltration membrane and preparation method thereof Download PDFInfo
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- CN107551833B CN107551833B CN201710933409.2A CN201710933409A CN107551833B CN 107551833 B CN107551833 B CN 107551833B CN 201710933409 A CN201710933409 A CN 201710933409A CN 107551833 B CN107551833 B CN 107551833B
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Abstract
The present invention relates to technical field of membrane separation, disclose a kind of pair of modified hollow fiber ultrafiltration membrane and preparation method thereof.Double modified hollow fiber ultrafiltration membranes of the invention are by spinning casting solution, coagulation bath and core liquid are made, spinning casting solution includes the Kynoar that weight percent is 14%-20%, the polyvinylpyrrolidone of 5%-16% and the organic solvent of 64%-81%, and the weight percent of three kinds of raw materials is 100%, coagulation bath includes the polyvinyl alcohol water solution that weight percent is 1%-10%, core liquid includes that weight percent is 30%-60% dimethylacetamide amine aqueous solution, double modified hollow fiber ultrafiltration membranes are hollow tubular, its section ecto-entad is successively are as follows: outer surface, tube wall and inner surface；Tube wall is asymmetric sponge cavernous structure, and the wall thickness of tube wall is 0.2~0.3mm；The pure water flux of double modified hollow fiber ultrafiltration membranes is greater than 700LMH, molecular cut off PEG100000, elongation 200-300%.The film wire good strength of double modified hollow fiber ultrafiltration membranes of the invention, hydrophily is good, to improve the service life of film and reduce the operating cost of component.
Description
Technical field
The present invention relates to technical field of membrane separation, especially a kind of double modified hollow fiber ultrafiltration membranes and preparation method thereof.
Background technique
Membrane separation technique is a kind of new separation technology of green high-efficient, ultrafiltration membrane technique therein have been used to separation,
Concentration, purifying and refined biological product, pharmaceutical products and food are also used to blood treatment, wastewater treatment and ultrapure water preparation
In terminal processing device.And hollow fiber ultrafiltration membrane is a kind of widely used filter medium, the substance that it can be removed includes
Biomolecule, high molecular polymer, colloidal substance are, it can be achieved that the technical process such as recycling, concentration, extraction.
Kynoar (abbreviation PVDF) is a kind of hemihedral crystal shaped polymer, and glass transition temperature is at -39 DEG C or so, fusing temperature
For degree at 160 DEG C or so, thermal decomposition temperature is higher than 316 DEG C.The macromolecular linear chain structure of PVDF is-CH2CF2, wherein C-F, C-H and
The respective bond energy of C-C is respectively 453,414.5,347.5KJ/mol.C-C key is as mass polymerization chain by F atom and H atom packet
It encloses, so that PVDF has splendid chemical stability, thermal stability and mechanical stability.By-CF2And-CH2- two
Group is alternately arranged, and so that PVDF is generated polarity, so as to be dissolved in certain polar solvents, such as dimethyl acetamide, N- first
Base pyrrolidones, dimethyl sulfoxide and dimethylformamide, this is but also PVDF is preferably led to non-solvent as one kind
Phase inversion prepares the material of pvdf membrane.Further develop and answer however, still remaining some problems and limiting pvdf membrane
With especially the purifying in some sewerages and separation field, for example preparation of drinking water, the processing of waste water and biology divide
From etc..Critical problem is as follows: in sewage of the processing comprising some natural organic compound such as protein, being not easy to moisten
Wet pvdf membrane is easily contaminated.Protein is easy to be adsorbed on film surface or blocks film surface apertures, to reduce permeability of the membrane
And last separation efficiency, reduce the service life of film, to improve membrane module replacement and maintenance cost.
Pvdf membrane about hardly possible wetting is a kind of likely the reason is that at the interface of pvdf membrane and water vulnerable to protein contamination
It there's almost no the association of hydrogen bond.The pvdf membrane surface of hardly possible wetting can generate repulsive interaction to hydrone and naturally along with entropy
Increase, this allows for protein molecule and is easy to the superficial layer that envelope surface is adsorbed and occupies film.In contrast, there is the film of hydrophilic layer
With high surface tension so as to by the hydrone of surrounding formed hydrogen bond come film and pollution main body between reconstruct one layer
Thin hydrone circle domain.For the pollutant of some difficult wettings, such as some protein, close to hydrosphere and its rule is destroyed
Whole structure is difficult, because this needs ever-increasing energy to remove hydrone circle domain to exposure pvdf membrane surface layer.
Therefore, improve the hydrophily of pvdf membrane by various methods to improve the service life of film and reduce the operation of component at
This, just seems significant.In recent years, having tested some different modes to adjust pvdf membrane surface.Physical modification
Two major classes, i.e. surface modification and blending and modifying can be divided into.Surface is modified to be typically employed in ready film surface coating or transfers
An one functional layer is connect, wherein in addition to some modified points are located in the aperture in film, it is most of to be modified point or in the upper surface of film
Or/and lower surface, it is limited that this is primarily due to the ability that the modified factor diffuses into fenestra.Blending and modifying is usually used in film system
The functionality of some anticipations is obtained during standby, that is to say, that the modification and preparation of film are that a step is completed in same process,
Just because of this, by the synergistic effect between PVDF and compatible additive, film surface similarly changes with having in film internal orifice dimension
Property chance.
However, the hydrophily for improving pvdf membrane only with a kind of modification mode does not obtain ideal effect.
If Chinese patent CN102974238 coats the modified hydrophily to promote ultrafiltration membrane using film surface, but this method of modifying
Due between film and coat mainly by physical absorption rather than chemical bond combines, force ratio is weaker, and coat is easy
It falls off from film surface, the hydrophily of film gradually weakens during using and cleaning, and cannot obtain persistent modified result.
On the other hand, it is with polysulfones in United States Patent (USP) US6045694 (Cationically charge-modified membranes)
Matrix membrane material is blended into the copolymer of vinyl pyrrolidone and cationic imidazolium compounds in film liquid, immerses after film forming
Containing modified ethyl polyvinyl and epoxychloropropane modified polyamine, then carries out heat cross-linking or radiation-induced crosslinking prepares lotus
Positive electricity Modified Membrane.But hydrophobic polymer and polymer-modified compatibility are bad, thus limit charged modification degree.
Summary of the invention
The purpose of the present invention is to provide a kind of double modified hollow fiber ultrafiltration membranes and preparation method thereof, to solve existing skill
Pvdf membrane is not since hydrophily is with great difficulty by protein contamination in art, thus membrane lifetime is lower, and the higher technology of operating cost is asked
Topic.
For this purpose, the present invention provides a kind of double modified hollow fiber ultrafiltration membranes, double modified hollow fiber ultrafiltration membranes by
Spinning casting solution, coagulation bath and core liquid are made, and the spinning casting solution includes the polyvinylidene fluoride that weight percent is 14%-20%
The organic solvent of alkene, the polyvinylpyrrolidone of 5%-16% and 64%-81%, and the weight percent of three kinds of raw materials is
100%, the coagulation bath includes the polyvinyl alcohol water solution that weight percent is 1%-10%, and the core liquid includes weight percent
Than for 30%-60% dimethylacetamide amine aqueous solution, double modified hollow fiber ultrafiltration membranes are hollow tubular, and section is by outer
Inwardly successively are as follows: outer surface, tube wall and inner surface；The tube wall is asymmetric spongelike structure, the wall thickness of tube wall is 0.2~
0.3mm；The pure water flux of double modified hollow fiber ultrafiltration membranes is greater than 700LMH, molecular cut off PEG100000, elongation
200-300%.
Preferably, the breaking strength 4-6Mpa of double modified hollow fiber ultrafiltration membranes, contact angle is less than 50 °.
The present invention also provides a kind of preparation methods of double modified hollow fiber ultrafiltration films, it is characterised in that the following steps are included:
(1) it stocks up: by the polyvinylpyrrolidone of Kynoar, 5%-16% that weight percent is 14%-20%
It is mixed with the organic solvent of 64%-81%, and the weight percent of three kinds of raw materials is 100%, is dissolved by heating, then standing and defoaming
24-48h obtains spinning casting solution；The polyvinyl alcohol that weight percent is 1-10% is added to the water, and polyethylene alcohol and water
The sum of weight percent is 100%, heats sufficiently dissolution and obtains coagulation bath,；It is 30%-60% dimethyl second by weight percent
Amide is added to the water, and the sum of weight percent of dimethyl acetamide and water is 100%, heats sufficiently dissolution and obtains core liquid；
(2) the spinning casting solution and core liquid are passed through into pump respectively and are transported to spinneret extrusion molding, spinning machine is passed through nitrogen
Gas, nitrogen pressure 0.3-0.5MPa；
(3) ultrafiltration membrane filaments of coming into being pass through the dry-spinning path of 1-10cm, then mix with coagulation bath obtained by step 1, and phase occurs and turns
Change, obtains hollow fiber film yarn；
(4) by ultrafiltration membrane filaments, wire wrapping wheel is wound under the linear velocity of 7-20m/min；
(5) film wire wound rinses again, dries preservation after being impregnated with glycerol-water-antiseptic mixed solution.
Preferably, the K value of the polyvinylpyrrolidone is 17 or 30.
Preferably, the organic solvent in the spinning casting solution is dimethylformamide, dimethyl acetamide, dimethyl Asia
The mixed liquor of one or more of sulfone, N-Methyl pyrrolidone, triethyl phosphate.
Preferably, the weight percent of the polyvinyl alcohol in the coagulation bath is 3%-6%.
Preferably, the heating temperature that spinning casting solution is prepared described in step 1 is 40-80 DEG C；Coagulation bath is prepared described in step 1
Heating temperature be 60-70 DEG C；The heating temperature that core liquid is prepared described in step 1 is 20-40 DEG C.
Preferably, dry-spinning path described in step 3 is 1-2cm.
It is further preferred that the temperature of mixed liquor described in step 5 is 20-30 DEG C, soaking time 24-48h.
Double modified hollow fiber ultrafiltration membranes of the invention compared with prior art, have the following beneficial effects:
1. integrated use of the present invention surface is modified and blending and modifying promotes the hydrophily of ultrafiltration membrane, respectively by casting
Polyvinylpyrrolidone is added in film liquid, polyvinyl alcohol is added in coagulation bath, to improve the service life of film and reduce component
Operating cost.
2. hydrophilic radical is fixed on film wire table due to being easily formed hydrogen bond between polyvinylpyrrolidone and polyvinyl alcohol
In face and inner passage, to ensure that the steady in a long-term of hydrophilic modifying.
3. this is conducive to improve phase process due to being easily formed hydrogen bond between polyvinylpyrrolidone and polyvinyl alcohol
Uniformity avoids film wire surface from forming macropore, to improve the intensity of film wire.
Detailed description of the invention
Fig. 1 is under 104 × amplification factor according to the scanning electron microscope image (SEM) in the film section of embodiment 1.
Specific embodiment
The preparation methods of double modified hollow fiber ultrafiltration membranes of the invention are prepared in accordance with the following methods, specifically include with
Lower step:
Step 1: spinning casting solution, coagulation bath and core liquid are prepared according to the dosage of each component in table 1, by PVDF, polyethylene
Three kinds of raw material mixing of pyrrolidones and organic solvent (the sum of weight percent of three kinds of raw materials is 100%), in 40-80 DEG C of condition
Lower stirring and dissolving 6-12 hours, then standing and defoaming 24-48h, obtain spinning casting solution；Polyvinyl alcohol is added to the water, is heated to
30-70 DEG C, dissolution is sufficiently stirred, obtains coagulation bath；Dimethyl acetamide is added to the water, is then heated to 20-40 DEG C, sufficiently
Stirring and dissolving obtains core liquid；
Step 2: the casting solution and core liquid are passed through into gear pump respectively and are transported to spinneret extrusion molding, spinning machine is passed through
Nitrogen, nitrogen pressure 0.3-0.5MPa；
Step 3: nascent ultrafiltration membrane filaments pass through the dry-spinning path of 1-10cm, then mix with coagulation bath obtained by step 1, occur
Inversion of phases obtains hollow fiber film yarn；
Step 4: by ultrafiltration membrane filaments, wire wrapping wheel is wound under the linear velocity of 7-20m/min；
Step 5: the film wire wound rinses again, dries preservation after being impregnated with glycerol-water-antiseptic mixed solution.
Table 1 respectively prepares the component and dosage of raw material in embodiment
In above-mentioned preparation embodiment, the hydrophilic additive of spinning casting solution is polyvinylpyrrolidone, can also be according to need
Add the mixture of one or more of polyethylene glycol, lithium chloride, lithium perchlorate, glycerine.Polyvinylpyrrolidine
The K value of ketone is 17 or 30.It is sub- that organic solvent in spinning casting solution is selected from dimethylformamide, dimethyl acetamide, dimethyl
The mixture of one or more of sulfone, N-Methyl pyrrolidone, triethyl phosphate.
Heating temperature when preparing spinning casting solution is 40-80 DEG C, and heating temperature is 20-40 DEG C when preparing core liquid.
The amount of polyvinyl alcohol is preferably 3%-6% in coagulation bath.Heating temperature is 30-70 DEG C when preparing coagulation bath, preferably
It is 60-70 DEG C.
Dry-spinning path is 1-10cm, preferably 1-2cm in step 4.
The temperature of mixed liquor described in step 5 is preferably 20-30 DEG C, and soaking time is preferably 24-48h.
The mechanism that the hydrophily and intensity of ultrafiltration membrane are significantly improved can be explained are as follows: the carbonyl in polyvinylpyrrolidone
Hydroxyl in base and polyvinyl alcohol forms hydrogen bond, hydrophilic radical is fixed in film wire surface and inner passage, to ensure that
Hydrophilic modifying it is steady in a long-term.
Comparative example 1
The preparation of spinning casting solution, the preparation of coagulation bath, the preparation of core liquid and hollow fibre are carried out using the method for embodiment 1
The spinning of ultrafiltration membrane is tieed up, when difference is that coagulation bath is prepared, non-Polyvinyl alcohol.
The performance comparison of the embodiment of the present invention and comparative example such as table 2.
The performance test results of table 2 comparative example and embodiment
| Embodiment/comparative example | Breaking strength (MPa) | Contact angle (degree) |
| Embodiment 1 | 5.5 | 44 |
| Embodiment 2 | 6.1 | 40 |
| Embodiment 3 | 6.4 | 40 |
| Embodiment 4 | 6.0 | 42 |
| Embodiment 5 | 4.8 | 37 |
| Embodiment 6 | 5.0 | 39 |
| Embodiment 7 | 4.6 | 35 |
| Embodiment 8 | 7.5 | 41 |
| Embodiment 9 | 6.6 | 37 |
| Comparative example 1 | 3.2 | 68 |
As shown in Table 2, embodiment 1-9 is compared with comparative example 1, by the way that polyvinyl alcohol is added in coagulation bath, can significantly mention
The breaking strength of high hollow fiber ultrafiltration membrane, contact angle are significantly reduced, and hydrophily significantly improves.
Claims (9)
1. a kind of double modified hollow fiber ultrafiltration membranes, it is characterised in that: double modified hollow fiber ultrafiltration membranes are by spinning casting film
Liquid, coagulation bath and core liquid are made, and the spinning casting solution includes Kynoar, the 5%- that weight percent is 14%-20%
16% polyvinylpyrrolidone and the organic solvent of 64%-81%, and the weight percent of three kinds of raw materials is 100%, it is described
Coagulation bath includes the polyvinyl alcohol water solution that weight percent is 1%-10%, and the core liquid includes that weight percent is 30%-
60% dimethylacetamide amine aqueous solution, double modified hollow fiber ultrafiltration membranes are hollow tubular, and section ecto-entad is successively
For outer surface, tube wall and inner surface；The tube wall is asymmetric spongelike structure, and the wall thickness of tube wall is 0.2~0.3mm；It is double to change
Property hollow fiber ultrafiltration membrane pure water flux be greater than 700LMH, molecular cut off PEG100000, elongation 200-300%.
2. double modified hollow fiber ultrafiltration membranes according to claim 1, it is characterised in that: double modified doughnuts are super
The breaking strength 4-6Mpa of filter membrane, contact angle is less than 50 °.
3. a kind of preparation method of double modified hollow fiber ultrafiltration membranes described in claim 1, it is characterised in that including following step
It is rapid:
(1) stock up: by weight percent be the Kynoar of 14%-20%, 5%-16% polyvinylpyrrolidone and
The organic solvent of 64%-81% mixes, and the weight percent of three kinds of raw materials is 100%, is dissolved by heating, then standing and defoaming 24-
48h obtains spinning casting solution；The polyvinyl alcohol that weight percent is 1-10% is added to the water, and the weight of polyethylene alcohol and water
The sum of amount percentage obtains coagulation bath for 100%, 30-70 DEG C of heating sufficiently dissolution, is 30%-60% diformazan by weight percent
Yl acetamide is added to the water, and the sum of weight percent of dimethyl acetamide and water is 100%, heats sufficiently dissolution and obtains core
Liquid；
(2) the spinning casting solution and core liquid are passed through into pump respectively and are transported to spinneret extrusion molding, spinning machine is passed through nitrogen, nitrogen
Atmospheric pressure is 0.3-0.5MPa；
(3) ultrafiltration membrane filaments of coming into being pass through the dry-spinning path of 1-10cm, then mix with coagulation bath obtained by step 1, inversion of phases occurs,
Obtain hollow fiber film yarn；
(4) ultrafiltration membrane filaments are wound under the linear velocity of 7-20m/min by wire wrapping wheel；
(5) film wire wound rinses again, dries preservation after being impregnated with glycerol-water-antiseptic mixed solution.
4. the preparation method of double modified hollow fiber ultrafiltration membranes according to claim 3, it is characterised in that: the poly- second
The K value of alkene pyrrolidone is 17 or 30.
5. the preparation method of double modified hollow fiber ultrafiltration membranes according to claim 3, it is characterised in that: the spinning
Organic solvent in casting solution is dimethylformamide, dimethyl acetamide, dimethyl sulfoxide, N-Methyl pyrrolidone, phosphoric acid
The mixed liquor of one or more of triethyl.
6. the preparation method of double modified hollow fiber ultrafiltration membranes according to claim 3, it is characterised in that: the gel
The weight percent of polyvinyl alcohol in bath is 3%-6%.
7. the preparation method of double modified hollow fiber ultrafiltration membranes according to claim 3, it is characterised in that: step 1 institute
The heating temperature for stating preparation spinning casting solution is 40-80 DEG C；The heating temperature that coagulation bath is prepared described in step 1 is 60-70 DEG C；Step
Rapid 1 heating temperature for preparing core liquid is 20-40 DEG C.
8. the preparation method of double modified hollow fiber ultrafiltration membranes according to claim 3, it is characterised in that: step 3 institute
Stating dry-spinning path is 1-2cm.
9. the preparation method of double modified hollow fiber ultrafiltration membranes according to claim 3, it is characterised in that: described in step 5
The temperature of mixed liquor is 20-30 DEG C, soaking time 24-48h.
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| CN108715801B (en) * | 2018-06-01 | 2021-12-03 | 苏州凯虹高分子科技有限公司 | Cell separation filter element and manufacturing method thereof |
| CN108854602A (en) * | 2018-06-28 | 2018-11-23 | 江苏泓膜业科技有限公司 | A kind of enhanced hollow fiber ultrafiltration membrane and preparation method thereof |
| CN111921384A (en) * | 2020-08-11 | 2020-11-13 | 浙江易膜新材料科技有限公司 | Casting membrane liquid of PVDF hollow fiber ultrafiltration membrane, spinning mechanism and production method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1418723A (en) * | 2002-07-19 | 2003-05-21 | 东华大学 | Large flux polyvinyl chlorid doughnut film, and its mfg. method |
| CN105363350A (en) * | 2014-08-31 | 2016-03-02 | 海南立昇净水科技实业有限公司 | Unsymmetrical chlorine-containing polymer-based charged type hollow fiber filtration membrane and preparation method thereof |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1418723A (en) * | 2002-07-19 | 2003-05-21 | 东华大学 | Large flux polyvinyl chlorid doughnut film, and its mfg. method |
| CN105363350A (en) * | 2014-08-31 | 2016-03-02 | 海南立昇净水科技实业有限公司 | Unsymmetrical chlorine-containing polymer-based charged type hollow fiber filtration membrane and preparation method thereof |
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