CN1068973A - Modified micro-pore film is used for film distillation and related film process - Google Patents
Modified micro-pore film is used for film distillation and related film process Download PDFInfo
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- CN1068973A CN1068973A CN 91105165 CN91105165A CN1068973A CN 1068973 A CN1068973 A CN 1068973A CN 91105165 CN91105165 CN 91105165 CN 91105165 A CN91105165 A CN 91105165A CN 1068973 A CN1068973 A CN 1068973A
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Abstract
The invention belongs to diffusion barrier and membrane separation technique.
The present invention adopts the microporous barrier of selected pore structure, is used for film distillation and related film process after surface-hydrophobicized modification, and the result shows that the Modified Membrane performance is better than the microporous barrier of making from hydrophobic material, has expanded the raw material source of dewatering microporous film to greatest extent.The present invention also be applicable to those can be used for film distillation and related film process but because of the strong not high dewatering microporous film of efficient of hydrophobicity, surface treatment can make the service efficiency of microporous barrier increase substantially through hydrophobization.
Description
The invention belongs to diffusion barrier and membrane separation technique.
Since nineteen sixty Loeb and Sourirajan invention prepares anisotropic membrane with phase inversion, membrane process such as micro-filtration, ultrafiltration, counter-infiltration are developed under the promotion of masking technique rapidly, the new membrane material continues to bring out thereupon, under the prerequisite that guarantees various stable performances, people wish to increase the hydrophily of film material to improve the permeation flux of microporous barrier, in decades, the structure control of microporous hydrophilic membrane research is deep day by day, ripe.
Development along with membrane material and filming technology, from the eighties initial stage, some new membrane separation processes are subject to people's attention and obtain exploitation, the common feature of these film separation processes be utilize diffusion barrier with the aqueous solution every living, the steam of volatile component is seen through, so must adopt hydrophobic microporous barrier, for example following film separation processes:
Film distillation (Membrane Distillation): dewatering microporous film is separated the aqueous solution of different temperatures, because warm side water vapor pressure is higher than cold side, so warm side steam constantly sees through film and enters cold side, obtain pure water in the cold side condensation, warm side solute is concentrated gradually, even can reach hypersaturated state.
Pressure reducing film distillation (Vacuum Membrane Distillation): in the film still-process, apply negative pressure, film both sides vapour pressure deficit is increased, thereby improve distillating ventilating amount less than liquid inlet pressure at the cold side of dewatering microporous film.
Evaporation absorbs (Gas Membrane): the side at dewatering microporous film is the aqueous solution that contains volatile solutes, opposite side is the aqueous solution of this volatile solutes adsorbent, in running, volatile solutes will see through fenestra and be adsorbed the agent absorption, and this membrane process has practical potentiality for the processing that contains volatile solutes waste water.
Osmotic distillation (Osmotic Distillation): in the warm side of dewatering microporous film is that desire concentrates feed liquid, cold side is a saturated brine, flux is significantly increased, objects such as fruit juice, milk, protein concentrated had Practical significance.
The infiltration evaporation of dewatering microporous film (Pervaporation with Hydrophobic porous Membrane): a side of dewatering microporous film is the volatile organic matter aqueous solution, apply negative pressure at opposite side less than liquid inlet pressure, the steam that sees through is through freezing collection, and the application of this process realizes that to sweat serialization has Practical significance.
Above the common feature of listed film separation process be to use dewatering microporous film, because capillary effect, the aqueous solution can not see through fenestra and the steam of volatile component can see through, up to now, the dewatering microporous film that is used for these membrane process all is by the hydrophobic polymer material preparation, materials such as polytetrafluoroethylene (PTFE) for example commonly used, polypropylene, Kynoar are made microporous barrier (W.T.Hanbury and T.Hodgkiess, Desalination, 56(1985) 287; R.W.Schofield, A.G.Fane and C.J.D.Fell, J.Membr.Sci., 33(1987) .299). experimental result shows, hydrophilic material such as cellulose acetate, the fine element of cellulose nitrate etc., the microporous barrier that makes since with water infiltration every the aqueous solution incessantly, so can not be directly used in above-mentioned those film separation processes, polytetrafluoroethylene (PTFE) and polyacrylic hydrophobicity are better, but can not be dissolved in organic solvent, can not can only adopt the pulling method microporous membrane with the phase inversion microporous membrane, in common lab, be difficult to realize, Kynoar is the hydrophobic material of being paid attention to by people at present, because it can be dissolved in the various polarity organic solvent, can make microporous barrier with phase inversion easily, in film distillation and above-mentioned relevant membrane process, be applied more widely, but from the contact angle data of water, the hydrophobicity of Kynoar is not very good, adopted water-soluble high-molecular material to make additive during especially with phase inversion, containing the trace water-soluble high-molecular material in the microporous barrier that makes is difficult to remove clean, can reduce the hydrophobicity of film significantly, thereby reduce the serviceability of dewatering microporous film.For example make polyvinylidene fluoride microporous film when adopting PVP to make additive with phase inversion, the aperture is 0.18 μ, is used for the film distillation test, and when warm side is 55 ℃ of 0.5MNaCl aqueous solution, when cold side was 25 ℃ of pure water, distillating ventilating amount had only 2.2Kg/m
2H, rejection is 99.1%.
Compare with dewatering microporous film, the microporous hydrophilic membrane that uses in micro-filtration, ultrafiltration, counter-infiltration is of a great variety, the research work of its pore structure control aspect is also more extensive, deep, ripe, if use with the surface-hydrophobicized modification of hydrophilic membrane and in film distillation and relevant membrane process, to expand the raw material source of dewatering microporous film undoubtedly to greatest extent, also will promote the deep development and the practicability of film distillation and related film process.
(" microporous barrier " described here is meant that those hydrophobicitys are not strong to the objective of the invention is to select the microporous barrier of pore structure, the microporous barrier that can not directly in film distillation and related film process, use, can be used for film distillation and related film process though also refer to those simultaneously, but the not high microporous barrier of efficient because hydrophobicity is not strong) carry out modification, make surface-hydrophobicized, obtain having the dewatering microporous film of selected pore structure, be applied to film distillation and relevant membrane process, (so-called here " relevant membrane process " is meant that those mechanisms of mass transfer are similar to the film distillation, be microporous barrier with the aqueous solution every living, the volatile component steam can see through other membrane process of fenestra).
Reaching in the relevant membrane process example as preceding cited film distillation, its common feature be adopt dewatering microporous film with the aqueous solution every living, and the steam of volatile component can enter opposite side from a side through fenestra, so the hydrophobicity of film and microporosity are to realize two necessary conditions of this class membrane process, the hydrophobicity of film belongs to the surface nature of film, in principle, the microporous barrier that any material is made, as long as certain means of employing are carried out hydrophobic modification with its surface, may be used to film distillation and relevant membrane process, its separating behavior only with the pore structure (aperture of film, porosity, morphosis etc.) relevant with the hydrophobicity on surface, and it is little with the material relation of film, this just makes us all hydrophobicitys might be not enough to be used for the microporous barrier of film distillation and related film process, comprise various materials, the microporous barrier of various forms is through using at above-mentioned membrane process after the surface-hydrophobicized modification; Those can be used in these membrane process, but the not high microporous barrier of efficient through after the surface modification, increases substantially its efficient because hydrophobicity is not strong, so particular content of the present invention comprises:
1. selected a kind of microporous barrier is as counterdie, and it can be organic film that any material is made, as cellulose family, polysulfones, polyamide-based, polyethers, polyesters, TPO, polyvinyl class, aromatic heterocyclic polymer class and inoranic membrane; It can be the film of any form, as flat sheet membrane, and hollow-fibre membrane, capillary-pipe film, tubular membrane, rolled film etc.; Its average pore size is between 0.001 μ-50 μ.
2. adopt effective surface modifying method to carry out surface-hydrophobicized processing, as means such as surface-coated, surface spraying, surface chemistry polymerization, surface grafting polymerization, surface irradiation grafting, the polymerizations of vacuum surface coating plasma surface; Can adopt one or more surface-hydrophobicized inorganic agents, as fluorine-containing material, siliceous material or other strong-hydrophobicity materials, the control modified condition just can obtain having different-thickness, different depth, the hydrophobic tectal microporous barrier in different aperture.
3. adopt the modified micro-pore film obtain: comprise because of hydrophobicity be not enough to the microporous barrier in film distillation and related film process, used hydrophobic turn to dewatering microporous film, also comprise can in above-mentioned membrane process, use but because of the not high microporous barrier of the strong efficient of hydrophobicity through its hydrophobic microporous barrier of hydrophobization processing the raising, film distillation and the mechanism of mass transfer related film process similar to the film distillation be microporous barrier with the aqueous solution every living, use in the membrane process of volatile component vapor permeable fenestra.
The present invention has following advantage:
1. any microporous barrier all can be used for film distillation and relevant membrane process after the surface-hydrophobicized modification, has expanded the raw material source of dewatering microporous film to greatest extent.
2. can choose at random the material and the pore structure of microporous barrier as required, the enriching achievement in research and can be applied aspect the dewatering microporous film of hydrophilic nanoporous membrane pore structure controlling party face in preparation.
3. have various surface modifying methods available, some method is simple, and for example cladding process all can be realized in any laboratory, and can obtain the high performance dewatering microporous film (seeing embodiment) that can be used for film distillation and related film process.
4. can select the top layer of any kind of strong-hydrophobicity material as Modified Membrane, be not subjected to the restriction of processing technology, using plasma surface aggregate method for example, can make various monomeric substances, not even with the monomeric substance of reactive functionality at surface aggregate, therefore can obtain the extremely strong Modified Membrane of hydrophobicity, improve the performance (seeing embodiment) of diffusion barrier greatly.
5. the experimental result of film distillation shows, the Modified Membrane that adopts suitable method of modifying to obtain, its performance can be better than the dewatering microporous film that makes from hydrophobic material.
Embodiment provided by the invention is as follows:
Embodiment 1: cellulose acetate microporous barrier (average pore size is 0.0015 μ) is 90: in the styrene 10(weight ratio)-pyridine grafting liquid, use Co under the blanket of nitrogen
60Irradiation 15 hours, close rate are 0.9 * 10
4Rad/h, it is clean with the ethanol rinsing to obtain film, and natural drying at room temperature 12 hours is used for the film distillation, and when warm side is 50 ℃ of 0.3MNaCl aqueous solution, when cold side was 20 ℃ of pure water, distillating ventilating amount was 1.36Kg/m
2H, rejection is 99,1%.
Embodiment 2: polyimides microporous barrier (average pore size is 0.021 μ), apply with 0.25% silicon rubber hexane solution, and get rid of unnecessary solvent, 60 ℃ of dryings 12 hours, be used for the film distillation, when warm side is 60 ℃ of 0.5M NaCl aqueous solution, when cold side was 25 ℃ of pure water, distillating ventilating amount was 23.4Kg/m
2H, rejection is 99.4%.
Embodiment 3: polysulfones microporous barrier (average pore size is 0.15 μ) is applied with 0.5% silicon rubber hexane solution, and all the other are operated with embodiment 2, and distillating ventilating amount is 31.4Kg/m
2H, rejection is 99.2%.
Embodiment 4: celluloid microporous barrier (average pore size is 1.0 μ) places external electrode formula plasma reactor, with the octafluorocyclobutane is that monomer carries out the plasma surface polymerization, glow discharge power is 60W, be 15 minutes discharge time, obtain Modified Membrane and be used for the film distillation, when warm side is 70 ℃ of 0.5M NaCl aqueous solution, when cold side was 25 ℃ of pure water, distillating ventilating amount was 34.0Kg/m
2H, rejection is 98.6%.
Embodiment 5: celluloid microporous barrier (average pore size is 6.5 μ), place external electrode formula plasma reactor, adopt vinyl trimethylsilane-carbon tetrafluoride monomer system, glow discharge power is 60W, be 5 minutes discharge time, obtains Modified Membrane and be used for the film distillation, when warm side is 60 ℃ of 0.5M NaCl aqueous solution, cold side is that 25 ℃ of pure water are, distillating ventilating amount is 40.5Kg/m
2H, rejection is 96.0%.
Embodiment 6: will press embodiment 2 methods with the asymmetric microporous barrier of Kynoar (average pore size is 0.18 μ) of phase inversion preparation and handle, obtain Modified Membrane and be used for the film distillation, when warm side is 55 ℃ of 0.5M NaCl aqueous solution, when cold side was 25 ℃ of pure water, distillating ventilating amount was 20.1Kg/m
2H, rejection is 99.0%, performance obviously is better than not adding the asymmetric microporous barrier of Kynoar of processing.
Embodiment 7: average pore size is the glass sand sintered plate of 20 μ, and with 10% silicon rubber hexane solution coated three times, each back that applies was 60 ℃ of oven dry 4 hours, be used for the film distillation test then, when warm side is 50 ℃ of 0.5M NaCl aqueous solution, when cold side was 25 ℃ of pure water, distillating ventilating amount was 4.8kg/m
2H, rejection is 82.0%.
Embodiment 8: density is 50g/m
2, average pore size be 45 μ from about polyester non-woven fabric, with 20% silicon rubber hexane solution coating three times, all 60 ℃ of oven dry 4 hours, the gained film is used for the film distillation, when warm side is 50 ℃ of 0.5MNaCl aqueous solution at every turn, when cold side was 25 ℃ of pure water, distillating ventilating amount was 4.5Kg/m
2H, rejection is 99.5%.
Claims (3)
1, modified micro-pore film is used for film distillation and related film process, it is characterized in that the selected a kind of microporous barrier of the present invention is as counterdie, it can be the film that any organic material is made, as cellulose family, polysulfones, polyamide-based, polyethers, polyesters, TPO, the polyvinyl class, aromatic heterocyclic polymer class and inoranic membrane, average pore size is between 0.001 μ-50 μ, handle through surface-hydrophobicized modification, obtain the modification dewatering microporous film, in film distillation and mechanism of mass transfer and the similar related film process of film distillation, be microporous barrier with the aqueous solution every living, use in the membrane process of volatile component vapor permeable fenestra.
2, modified micro-pore film as claimed in claim 1 is used for film distillation and related film process, it is characterized in that described microporous barrier is meant those because hydrophobicity can not be used for the microporous barrier of film distillation and related film process by force.
3, modified micro-pore film as claimed in claim 1 is used for film distillation and related film process, it is characterized in that this process comprises can be used for the dewatering microporous film of film distillation and related film process, but, need carry out surface modification to improve the situation of film properties because the hydrophobicity of film is not strong.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 91105165 CN1068973A (en) | 1991-07-26 | 1991-07-26 | Modified micro-pore film is used for film distillation and related film process |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 91105165 CN1068973A (en) | 1991-07-26 | 1991-07-26 | Modified micro-pore film is used for film distillation and related film process |
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| CN1068973A true CN1068973A (en) | 1993-02-17 |
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| CN 91105165 Pending CN1068973A (en) | 1991-07-26 | 1991-07-26 | Modified micro-pore film is used for film distillation and related film process |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100348504C (en) * | 2005-10-13 | 2007-11-14 | 李保安 | Directly contacting distillation desalting hollow fiber membrane apparatus and method |
| US7305850B2 (en) | 2004-07-23 | 2007-12-11 | Velocys, Inc. | Distillation process using microchannel technology |
| US7610775B2 (en) | 2004-07-23 | 2009-11-03 | Velocys, Inc. | Distillation process using microchannel technology |
| CN102228801A (en) * | 2011-05-16 | 2011-11-02 | 何涛 | Hydrophobically modified distillation membrane material of high throughout and high salt rejection rate and application thereof |
| CN102964625A (en) * | 2012-11-27 | 2013-03-13 | 海南大学 | Method for preparing hydrophobic block cellulose aerogel thermal insulation material |
| WO2013037088A1 (en) * | 2011-09-16 | 2013-03-21 | General Electric Company | A method for improving performance of a membrane used in membrane distillation |
| CN106076121A (en) * | 2016-06-12 | 2016-11-09 | 南京工业大学 | A kind of Membrane Materials desalination process and device |
| CN112993212A (en) * | 2019-12-14 | 2021-06-18 | 中国科学院大连化学物理研究所 | Three-dimensional porous elastic electrode and preparation and application thereof |
-
1991
- 1991-07-26 CN CN 91105165 patent/CN1068973A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7305850B2 (en) | 2004-07-23 | 2007-12-11 | Velocys, Inc. | Distillation process using microchannel technology |
| US7610775B2 (en) | 2004-07-23 | 2009-11-03 | Velocys, Inc. | Distillation process using microchannel technology |
| CN100348504C (en) * | 2005-10-13 | 2007-11-14 | 李保安 | Directly contacting distillation desalting hollow fiber membrane apparatus and method |
| CN102228801A (en) * | 2011-05-16 | 2011-11-02 | 何涛 | Hydrophobically modified distillation membrane material of high throughout and high salt rejection rate and application thereof |
| CN102228801B (en) * | 2011-05-16 | 2014-03-12 | 何涛 | Hydrophobically modified distillation membrane material of high throughout and high salt rejection rate and application thereof |
| WO2013037088A1 (en) * | 2011-09-16 | 2013-03-21 | General Electric Company | A method for improving performance of a membrane used in membrane distillation |
| CN102964625A (en) * | 2012-11-27 | 2013-03-13 | 海南大学 | Method for preparing hydrophobic block cellulose aerogel thermal insulation material |
| CN106076121A (en) * | 2016-06-12 | 2016-11-09 | 南京工业大学 | A kind of Membrane Materials desalination process and device |
| CN112993212A (en) * | 2019-12-14 | 2021-06-18 | 中国科学院大连化学物理研究所 | Three-dimensional porous elastic electrode and preparation and application thereof |
| CN112993212B (en) * | 2019-12-14 | 2022-04-22 | 中国科学院大连化学物理研究所 | Three-dimensional porous elastic electrode and preparation and application thereof |
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