CN101293184A - Process for manufacturing large-flux anti-pollution PVDF hollow fiber external pressure film - Google Patents
Process for manufacturing large-flux anti-pollution PVDF hollow fiber external pressure film Download PDFInfo
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- CN101293184A CN101293184A CNA2008100536066A CN200810053606A CN101293184A CN 101293184 A CN101293184 A CN 101293184A CN A2008100536066 A CNA2008100536066 A CN A2008100536066A CN 200810053606 A CN200810053606 A CN 200810053606A CN 101293184 A CN101293184 A CN 101293184A
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Abstract
The present invention discloses a preparation method of high-flux anti-pollution PVDF hollow fiber outside-pressure membrane. The present invention relates to a manufacturing technology of a hollow fiber membrane, in particular to a modified manufacturing technology for increasing the flux of the PVDF hollow fiber membrane. The preparation method includes pretreatment and radiation grafting. The present invention is characterized by simple process, easy industrial implementation, etc. The surface and the hole interior of the high-flux PVDF hollow fiber membrane manufactured by the present invention have carboxyl; the hydrophilicity is increased and the pollution resistance of the membrane is also enhanced. Compared with the ordinary modifying method, the manufacturing method of the high-flux PVDF-g-PAAc hollow fiber outside-pressure membrane has the advantages of short production flow, simple process, wide application, no special equipment required and easy industrial popularization and implementation.
Description
Technical field
The invention belongs to membrane material and make the field, relate to the modification manufacturing technology of film.
Background technology
Hollow-fibre membrane is a kind of filtration membrane material with cannulated structure.Owing to have characteristics such as good pressure-resistant performance, loading density are big, the membrane area of unit volume is big, be widely used in water treatment, biological medicine and various fields such as gas separates.
The PVDF hollow-fibre membrane is a kind of special fibre film that new development is got up, have chemical stability, high resistance tocrocking, radiation resistance, hear resistance and good physical and mechanical properties, become one of best film kind of the interior combination property of present world wide, but also have problems such as flux is less relatively, fenestra pollutes easily, the aperture is big, rejection is low.
The approach that improves PVDF doughnut membrane flux mainly contains the hydrophily and the appropriateness that improve film and increases membrane aperture, increases resistance tocrocking mainly by improving the hydrophily of film, and therefore improving the film hydrophily becomes present main methods of modification.Specifically can be divided into infusion method, grafting method and blending method.
The method that appropriateness improves membrane aperture mainly is to utilize oxidant or solvent to carry out reaming after the film forming.Particularly clorox (NaClO) is handled and is widely used, but the processing time is long, and concentration of treatment is too high all can to have harmful effect to the mechanical property of film.
Infusion method is a kind of simple physics method of modifying, adopts water-soluble solvent or surfactant to soak pvdf membrane with contact angle that reduces pvdf membrane and the resistance that reduces by fenestra, realize that pvdf membrane is temporary hydrophilic, but its effect can not be kept for a long time.Dong Shengxiong etc. adopt non-ionic surface active agent Tween80 aqueous solution soaking PVDF milipore filter, the dry film of dehydration is handled through infusion method after, the flux of milipore filter can maintain 75% of wet film.
The blending method modification normally mixes hydroaropic substance in PVDF, can be big molecular additives, inorganic salts, also can be nano-metal-oxide.Ma Jun etc. (Chinese patent CN1687222A) adopt the Kynoar of 16 (wt) % to be dissolved in N, in the N dimethyl formamide, and the average grain diameter that adds 5 (wt) % polyethylene glycol, 0.3 (wt) % anhydrous Lithium chloride and 0.3 (wt) % is the titanium dioxide of 10nm, in temperature is 16 ℃, humidity is under 37% condition, casting solution is scraped on nonwoven and is made the thick liquid film of 0.2 1 0.8mm, carries out the polyvinylidene fluoride film that inversion of phases obtains being mixed with nano titanium oxide in 16 ℃ coagulating bath.Improved the hydrophily of Kynoar, and the gained polyvinylidene fluoride film is difficult for contaminatedly, do not need often to clean, the film pure water flux improves, and is big to the rejection of bovine serum albumin(BSA), and the pure water flux reduction of having filtered the Bovine Serum Albumin in Aqueous Solution caudacoria is less.
The grafting method is to introduce hydrophilic radical by covalent bond on the film matrix, therefore effect can keep for a long time, the initiation mode mainly contains modes such as redox, gamma-radiation radiation, plasma resonance, ultraviolet light initiation, by introduce the hydrophilic modifying that hydrophilic radical improves film on pvdf membrane.
The pre-radiation pvdf membrane of human gamma-rays such as Lu Xiaofeng causes the gas-phase benzene vinyl polymerization, and sulfonation obtains the PVDF milipore filter of possess hydrophilic property then, and its surface contact angle to water diminishes, and to the rejection increase of bovine serum albumin(BSA), resistance tocrocking improves.People such as Shao Pinghai are after HF is taken off in the gamma-rays radiation, in the acidic reduction environment, carry out necleophilic reaction again, hydroxyl is introduced on surface at film, further introduce hydrophilic macoradical then on the surface of film, as polyvinylpyrrolidone (PVP), polyethylene glycol (PEG) etc., make the film surface form stable hydrophily top layer, make well behaved hydrophilic PVDF film, water flux returns to 95% of original wet film.Flat Zheng Hua etc. (Chinese patent CN1858090A) combine blend and surface grafting technology, earlier with PVDF with (polyether sulfone, the pyrrolidones etc.) blend of another kind of photosensitive polymers and make microporous barrier or dense film, adopt low pressure mercury lamp ultraviolet irradiation surface grafting method at hydrophilic monomers such as blend film surface grafting acrylic acid then.The Modified Membrane that makes had both kept excellent chemical stability that polyvinylidene fluoride microporous film had and mechanical performance, and the surface hydrophilicity of film and resistance tocrocking are greatly improved.
But said method all needs multistep reaction, and water flux does not obviously improve, reaction condition is relatively harsher, be difficult to amplify, therefore, it is simple to study a kind of manufacture method, and the PVDF hollow-fibre membrane that flux height and resistance tocrocking are good is an important directions of present film research, and has not yet to see report about the document that radiation grafting acrylic acid prepares the outer press mold of big flux PVDF doughnut.
Summary of the invention
At the deficiencies in the prior art, the technical problem that quasi-solution of the present invention is determined provides the manufacture method of the outer press mold of a kind of big flux Kynoar (PVDF) doughnut.This hollow-fibre membrane has big flux, high rejection and higher resistance tocrocking; Characteristics such as it is simple that its preparation method has technology, and industrializing implementation is easy.
The technical scheme that the present invention solves the manufacture method technical problem of the outer press mold of described big flux PVDF doughnut is: design a kind of big flux PVDF hollow-fibre membrane, its manufacture method comprises:
1. pre-treatment: adopt clorox to handle,, handle 5-20h with alcohol immersion and/or with 0.5g/L-1g/L aqueous sodium hypochlorite solution (pH=10.5) then with PVDF hollow-fibre membrane distilled water immersion 5h-20h.
2. radiation grafting: the hollow-fibre membrane of handling well put into the acrylic acid aqueous solution that volumetric concentration is 0.05%-30% is housed; feeding nitrogen protects; by dose of radiation is 10kGy-40kGy; radiated time is that the radiation condition of 5h-80h is at room temperature used the gamma-radiation radiation; take out and clean, can obtain the outer press mold of modification large-flux anti-pollution PVDF-g-PAAc doughnut.
The high flux PVDF hollow-fibre membrane surface and the inside, hole of the inventive method manufacturing have carboxyl, and hydrophily improves.When percent grafting equaled 4.4%, pure water flux was from the 834L/m of former film
2H brings up to 1499L/m
2H has improved 79.9%; Less than 4.4% o'clock, pure water flux increased with the raising of percent grafting at percent grafting; After percent grafting was less than 4.4%, pure water flux reduced with the raising of percent grafting.When reason was that percent grafting is relatively lower on the film surface, the grafted chain density that has carboxyl was very low, has improved hydrophily, and grafted chain length is very short simultaneously, can not form rake and stop up fenestra, thereby improve pure water flux; Raising along with percent grafting, the grafted chain density on graft copolymer membrane surface increases, its length increases, form rake, increase the resistance of pure water by rete, the also possible blocking portion fenestra of grafted chain reduces the porosity of film, and the aperture reduces, be grafted on the carboxyl ionization in water near the acrylic acid-grafted chain of fenestra simultaneously, because electrostatic interaction, polyacrylic acid grafted chain-unfolding further makes the aperture of film reduce, increased the osmotic resistance of pure water, and percent grafting is high more, and this effect also can be strong more, causes the decline of the pure water flux of film.
The outer press mold of large-flux anti-pollution PVDF-g-PAAc doughnut also increases substantially the rejection of bovine serum albumin, and is lower than the rising with percent grafting in 4.4% o'clock at percent grafting and increases (referring to accompanying drawing 2).Because the raising of percent grafting not only makes the aperture of film reduce, help holding back, increased electronegative carboxyl simultaneously, made film that protein is had stronger electrostatic interaction again, this two aspects acting in conjunction has improved the rejection of big flux PVDF-g-PAAc hollow-fibre membrane to bovine serum albumin.
The outer press mold of big flux PVDF-g-PAAc doughnut also has raising to the resistance tocrocking of protein, and improves (referring to accompanying drawing 3) with the increase of percent grafting.This is because radiation-induced graft copolymerization has been introduced hydrophilic radical, and the film surface hydrophilicity increases, thereby makes the contamination resistance of film be improved.
Based on above characteristic, the outer press mold of the big flux PVDF-g-PAAc of the present invention doughnut can be used for field films such as water treatment, biological medicine and separate.Compare with the outer press mold of present existing PVDF doughnut, film surface and inside, hole have hydrophilic carboxyl functional group, and it is big to have a pure water flux, to bovine serum albumin rejection height and antipollution height, characteristics such as application form is extensive, thereby have bright development prospect and purposes widely.The big flux PVDF-g-PAAc of the present invention doughnut external pressure film manufacturing method is compared with general method of modifying, and production procedure is short, and technology is simple, and applicability is wide, does not need special installation, and industrialization promotion is implemented easily.
Description of drawings
Fig. 1 for the pure water flux of modification PVDF hollow-fibre membrane of the present invention with the percent grafting change curve.
Fig. 2 for modification PVDF hollow-fibre membrane of the present invention to the rejection of bovine serum albumin with the percent grafting change curve.
Fig. 3 for the flux recovery rate of modification PVDF hollow-fibre membrane of the present invention with the percent grafting change curve.
The specific embodiment
Further narrate the present invention below in conjunction with embodiment:
The manufacture method of strong acid ion exchange fiber of the present invention comprises:
1. pre-treatment: adopt clorox to handle,, handle 5-20h and/or handle 5-20h with alcohol immersion then with 0.5g/L-1g/L aqueous sodium hypochlorite solution (pH=10.5) with PVDF hollow-fibre membrane distilled water immersion 10h.
2. radiation grafting: the hollow-fibre membrane of handling well put into the acrylic acid aqueous solution that volumetric concentration is 0.05%-20% is housed; feeding nitrogen protects; by dose of radiation is 5kGy-40kGy; radiation dose rate (0.5kGy/h-3kGy/h); use the gamma-radiation radiation; prepare the outer press mold of modification large-flux anti-pollution PVDF-g-PAAc doughnut of percent grafting 2.5%-9.1%, film pure water flux＞1000L/m
2H is to the also corresponding raising with the water flux recovery rate of rejection of bovine serum albumin.
Say that simply the inventive method is: by being total to method of radiating, carrying out modification with gamma-radiation radiation PVDF hollow-fibre membrane surface and handle, form free radical, carry out graft reaction with monomer acrylic acid and can obtain described high flux anti-pollution PVDF hollow-fibre membrane.
The employed matrix material of high flux anti-pollution PVDF hollow-fibre membrane of the present invention is a Kynoar.Kynoar is the extremely strong macromolecular material of inertia, have very excellent chemical stability, acid and alkali-resistance, corrosion resistance, can in very wide temperature range, use, especially at high temperature stable, design also will keep these excellent performances to a certain extent with the high flux PVDF hollow-fibre membrane that it is matrix is prepared, and, realize purpose of the present invention because polyacrylic acid has good hydrophilicity.
High flux anti-pollution PVDF hollow-fibre membrane of the present invention adopts radiation grafted manufacture method, be to have made full use of the strong advantage of radiation grafting ray penetration power, can finish general chemical method and be difficult to the graft reaction that carries out, and simple, convenient easy row, can finish under the room temperature.
The dose of radiation of manufacture method design of the present invention is controlled at 5kGy-40kGy, radiated time is controlled at 5h-40h, grafted monomers acrylic acid concentration (percent by volume) is controlled at 0.05%-20%, in this scope of design, the inventive method can obtain the grafting PVDF hollow-fibre membrane that percent grafting is 1.03%-9.1%.
Experimental result shows: dose of radiation is low, radiated time is short, when grafted monomers concentration is hanged down, resultant film percent grafting is lower, for example: dose of radiation is 10kGy, and radiated time is 5 hours, and the acrylic monomers percent by volume is 0.5 o'clock, can obtain percent grafting is 3.36%, and the flux of the PVDF hollow-fibre membrane that makes is 1296L/m
2H.Otherwise then high, for example: dose of radiation is 20kGy, and radiated time is 20 hours, and the acrylic monomers percent by volume is 1 o'clock, and can obtain percent grafting is 8.1%, and the flux of the PVDF hollow-fibre membrane that makes is 1200L/m
2H.
The manufacture method of the outer press mold of large-flux anti-pollution PVDF of the present invention-g-PAAc doughnut is when radiation grafting, selecting acrylic acid for use is to consider behind graft acrylic acid on the film matrix as polymer monomer, thereby can make the PVDF hollow-fibre membrane of high purity water flux by the hydrophily that improves fenestra and film surface.
The manufacture method of the PVDF hollow-fibre membrane of high purity water flux of the present invention has also adopted nitrogen protection when radiation grafting, its objective is that the mechanical strength that makes hollow-fibre membrane is not subjected to serious evil when radiation, to satisfy the needs that use.
Utilize described the inventive method can make the PVDF-g-PAAc hollow-fibre membrane of the high purity water flux anti-pollution of a series of performances and specification.
Introduce specific embodiments of the invention below, but the present invention is not subjected to the restriction of embodiment:
Embodiment 1:
Pre-treatment: adopt clorox to handle, with the PVDF hollow-fibre membrane (Tianjin MoTian Membrane Engineering Technology Co., Ltd produces, external diameter 1.05mm, average pore size 0.2 μ m, the film pure water flux is 834L/m
2H) use distilled water immersion 10h, handle 10h with alcohol immersion again after the taking-up, handle 10h with 0.5g/L 1 aqueous sodium hypochlorite solution (pH=10.5).
To be dipped in percent by volume through the Kynoar hollow-fibre membrane of pre-treatment and be in 0.5% the acrylic acid aqueous solution; feed nitrogen protection; it is 12.5 hours at room temperature with gamma-radiation radiation 25kGy, radiated time; take out cleaning and can obtaining percent grafting is 6.7% PVDF hollow-fibre membrane, and flux is 1381L/m
2H brings up to 28.9% to the rejection of bovine serum albumin from 5.2% of former film, and the water flux recovery rate brings up to 95.6% from 87.3% of former film.
Embodiment 2:
Pre-treatment: adopt clorox to handle, with the PVDF hollow-fibre membrane (Tianjin MoTian Membrane Engineering Technology Co., Ltd produces, external diameter 1.05mm, average pore size 0.2 μ m, the film pure water flux is 834L/m
2H) use distilled water immersion 10h, handle 10h with 0.5g/L 1 aqueous sodium hypochlorite solution (pH=10.5).
It is in 1% the acrylic acid aqueous solution that the Kynoar hollow-fibre membrane is dipped in percent by volume; feed nitrogen protection; it is 20 hours at room temperature with gamma-radiation radiation 20kGy, radiated time; take out cleaning and can obtaining percent grafting is 8.1% PVDF hollow-fibre membrane; flux is 1200L/m2h; rejection to bovine serum albumin brings up to 31.6% from 5.2% of former film, and the water flux recovery rate brings up to 95.9% from 87.3% of former film.。
Embodiment 3: pre-treatment is with example 2
Pre-treatment: adopt clorox to handle, with the PVDF hollow-fibre membrane (Tianjin MoTian Membrane Engineering Technology Co., Ltd produces, external diameter 1.05mm, average pore size 0.2 μ m, the film pure water flux is 834L/m
2H) use distilled water immersion 10h, handle 10h with 1g/L 1 aqueous sodium hypochlorite solution (pH=10.5).
It is in 1% the acrylic acid aqueous solution that the Kynoar hollow-fibre membrane is dipped in percent by volume; feed nitrogen protection; at room temperature use gamma-radiation radiation 20kGy, 10 hours; take out cleaning and can obtaining percent grafting is 4.4% PVDF hollow-fibre membrane; flux is 1499L/ (m2h); rejection to bovine serum albumin brings up to 27.1% from 5.2% of former film, and the water flux recovery rate brings up to 94.5% from 87.3% of former film.
Embodiment 4:: pre-treatment is with example 2
It is in 0.5% the acrylic acid aqueous solution that the Kynoar hollow-fibre membrane is dipped in percent by volume; feed nitrogen protection; at room temperature use gamma-radiation radiation 10kGy, 5 hours; take out cleaning and can obtaining percent grafting is 3.36% PVDF hollow-fibre membrane; flux is 1296L/ (m2h); rejection to bovine serum albumin brings up to 21.0% from 5.2% of former film, and the water flux recovery rate brings up to 93.3% from 87.3% of former film.
Embodiment 5: pre-treatment is with example 1
It is in 20% the acrylic acid aqueous solution that the Kynoar hollow-fibre membrane is dipped in percent by volume; feed nitrogen protection in the closed container; at room temperature use gamma-radiation radiation 5kGy, 5 hours, take out and clean that can to obtain percent grafting be 9.1% PVDF hollow-fibre membrane, flux is 1127L/ (m
2H), the rejection of bovine serum albumin is brought up to 32.0% from 5.2% of former film, the water flux recovery rate brings up to 95.5% from 87.3% of former film.
Embodiment 6: pre-treatment is with example 1
It is in 0.05% the acrylic acid aqueous solution that the Kynoar hollow-fibre membrane is dipped in percent by volume; feed nitrogen protection in the closed container; at room temperature use gamma-radiation radiation 40kGy, 40 hours, take out and clean that can to obtain percent grafting be 6.6% PVDF hollow-fibre membrane, flux is 1385L/m
2H brings up to 28.6% to the rejection of bovine serum albumin from 5.2% of former film, and the water flux recovery rate brings up to 95.0% from 87.3% of former film.
Claims (6)
1. the manufacture method of the outer press mold of large-flux anti-pollution PVDF doughnut comprises the steps:
(1) film pre-treatment: PVDF hollow-fibre membrane distilled water immersion 5-20h, alcohol immersion 5-20h and/or aqueous sodium hypochlorite solution are handled 5-20h;
(2) radiation grafting: the hollow-fibre membrane of handling well is put into the acrylic acid aqueous solution that volumetric concentration is 0.05%-20%, and the gamma-radiation radiation is 5kGy-40kGy by dose of radiation, and radiated time is 5-40h, cleans promptly.
2. the manufacture method of the outer press mold of large-flux anti-pollution PVDF doughnut according to claim 1 is characterized in that described dose of radiation is 10kGy-20kGy, and radiated time is 5h-20h.
3. the manufacture method of the outer press mold of large-flux anti-pollution PVDF doughnut according to claim 1 is characterized in that the acrylic acid aqueous solution volumetric concentration is 0.5%-10%.
4. the manufacture method of the outer press mold of large-flux anti-pollution PVDF doughnut according to claim 1 is characterized in that radiation-induced graft copolymerization is carrying out under room temperature, nitrogen protection.
5. the manufacture method of the outer press mold of large-flux anti-pollution PVDF doughnut according to claim 1 is characterized in that radiation-induced graft copolymerization carries out in closed container.
6. the manufacture method of the outer press mold of large-flux anti-pollution PVDF doughnut according to claim 1 is characterized in that aqueous sodium hypochlorite solution concentration is 0.5g/L-1g/L in the described pre-treatment.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101890310A (en) * | 2010-04-23 | 2010-11-24 | 苏州膜华材料科技有限公司 | Porous membrane using acetic acid-2-ethoxyl ethyl ester and polyethylene glycol as diluents and preparation method |
| CN107115795A (en) * | 2017-03-24 | 2017-09-01 | 浙江师范大学 | A kind of flux in acid condition has seperation film of pH dependences and preparation method thereof |
| CN109550412A (en) * | 2018-12-12 | 2019-04-02 | 湖南恒业城市环境科技有限公司 | A kind of acid resistance polyphenylsulfone ultrafiltration membrane and preparation method thereof |
| CN110975649A (en) * | 2019-11-19 | 2020-04-10 | 江苏大孚膜科技有限公司 | Modified polyvinylidene fluoride ultrafiltration membrane and preparation method thereof |
| CN112569813A (en) * | 2020-11-19 | 2021-03-30 | 厦门大学 | Preparation method of inorganic nano material reinforced hollow fiber ultrafiltration membrane |
| CN113083030A (en) * | 2021-03-30 | 2021-07-09 | 浙江师范大学 | Anti-pollution high-flux modified polymer separation membrane and preparation method thereof |
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2008
- 2008-06-23 CN CNA2008100536066A patent/CN101293184A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101890310A (en) * | 2010-04-23 | 2010-11-24 | 苏州膜华材料科技有限公司 | Porous membrane using acetic acid-2-ethoxyl ethyl ester and polyethylene glycol as diluents and preparation method |
| CN101890310B (en) * | 2010-04-23 | 2013-11-06 | 苏州膜华材料科技有限公司 | Porous membrane using acetic acid-2-ethoxyl ethyl ester and polyethylene glycol as diluents and preparation method |
| CN107115795A (en) * | 2017-03-24 | 2017-09-01 | 浙江师范大学 | A kind of flux in acid condition has seperation film of pH dependences and preparation method thereof |
| CN107115795B (en) * | 2017-03-24 | 2021-01-19 | 浙江师范大学 | Separation membrane with pH-dependent flux under acidic condition and preparation method thereof |
| CN109550412A (en) * | 2018-12-12 | 2019-04-02 | 湖南恒业城市环境科技有限公司 | A kind of acid resistance polyphenylsulfone ultrafiltration membrane and preparation method thereof |
| CN110975649A (en) * | 2019-11-19 | 2020-04-10 | 江苏大孚膜科技有限公司 | Modified polyvinylidene fluoride ultrafiltration membrane and preparation method thereof |
| CN112569813A (en) * | 2020-11-19 | 2021-03-30 | 厦门大学 | Preparation method of inorganic nano material reinforced hollow fiber ultrafiltration membrane |
| CN113083030A (en) * | 2021-03-30 | 2021-07-09 | 浙江师范大学 | Anti-pollution high-flux modified polymer separation membrane and preparation method thereof |
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Open date: 20081029 |