CN115624868B - Reverse osmosis membrane and preparation method thereof - Google Patents
Reverse osmosis membrane and preparation method thereof Download PDFInfo
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- CN115624868B CN115624868B CN202211653251.0A CN202211653251A CN115624868B CN 115624868 B CN115624868 B CN 115624868B CN 202211653251 A CN202211653251 A CN 202211653251A CN 115624868 B CN115624868 B CN 115624868B
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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
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0095—Drying
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
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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
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0083—Thermal after-treatment
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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
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0088—Physical treatment with compounds, e.g. swelling, coating or impregnation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/08—Specific temperatures applied
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/30—Cross-linking
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
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Abstract
The invention relates to the technical field of membrane separation, in particular to a reverse osmosis membrane and a preparation method thereof. The preparation method comprises the following steps: soaking the basement membrane in the aqueous phase solution, taking out, performing primary drying and absorption through vacuum water absorption, and then drying again; the aqueous phase solution comprises polyamine monomers and additives; then, coating an oil phase solution on the obtained basement membrane; the oil phase solution comprises acyl chloride and an organic solvent; the membrane obtained by preliminary reaction of the oil phase solution is sequentially reacted in three hot air environments, wherein the first hot air environment mainly comprises drying of redundant oil phase solvent and additional cross-linking reaction, and the second hot air environment mainly comprises further cross-linking reaction; and the third hot air environment is low-temperature treatment, and the stable structure of the reaction layer is mainly ensured by rapid cooling. The steps can interact better, and the finally prepared reverse osmosis membrane has better membrane flux and membrane desalination rate.
Description
Technical Field
The invention relates to the technical field of membrane separation, in particular to a reverse osmosis membrane and a preparation method thereof.
Background
Composite very low pressure reverse osmosis membranes generally consist of a nonwoven layer, a porous support layer, and a separation layer. At present, a plurality of porous supporting layers are mainly formed on the surface of a non-woven fabric layer by polysulfone/DMF through a phase inversion method, and a separation layer is formed on the porous supporting layers by m-phenylenediamine and trimesoyl chloride through interfacial polymerization. The separating layer determines the separating properties of the composite membrane, while the base membrane provides mainly mechanical strength. The performance of the composite ultra-low pressure reverse osmosis membrane is mainly determined by the structure (pore size, porosity, thickness, roughness surface charge, hydrophilicity and the like) of a separation layer and the chemical properties (factors such as functional groups, bond energy, crosslinking degree and the like) of the separation layer, and the composite ultra-low pressure reverse osmosis membrane is generally formed by the interfacial polymerization reaction and further crosslinking reaction of water phase monomers and oil phase monomers at an oil-water interface which are not mutually soluble, so the structure and the performance of the separation layer can be optimized by controlling the process conditions of the reaction.
At present, in the production of the ultra-low pressure reverse osmosis membrane, in order to improve the flux of the membrane, the process control of interfacial polymerization and crosslinking reaction is less concerned from a formula system and a post-treatment additive. The existing crosslinking reaction process is generally finished in an integrated oven, and the process is not controlled in stages, so that the crosslinking reaction process cannot be effectively regulated and controlled; meanwhile, the process of the cross-linking reaction is only regarded as a receiving process of the former process, and how to avoid the negative influence of the latter process on the membrane flux is not considered.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a reverse osmosis membrane and a preparation method thereof, wherein the reverse osmosis membrane prepared by the present invention has excellent membrane flux and membrane salt rejection.
The invention provides a preparation method of a reverse osmosis membrane, which comprises the following steps:
a) Soaking the basement membrane in the aqueous phase solution, taking out, performing primary drying and absorption through vacuum water absorption, and then drying again; the aqueous phase solution comprises polyamine monomers and additives;
b) Coating an oil phase solution on the basement membrane obtained in the step A); the oil phase solution comprises acyl chloride and an organic solvent;
c) Carrying out a first reaction on the membrane obtained in the step B) in a first hot air environment; the temperature of the first reaction is 70 to 100 ℃;
d) Carrying out a second reaction on the membrane obtained in the step C) in a second hot air environment; the temperature of the second reaction is 50 to 70 ℃;
e) Carrying out a third reaction on the membrane obtained in the step D) in a third hot air environment to obtain a reverse osmosis membrane; the temperature of the third reaction is 10 to 20 ℃.
Preferably, in the step a), the base film comprises polysulfone nonwoven fabric.
Preferably, in step a), the polyamine monomer comprises m-phenylenediamine;
the additive comprises sodium dodecyl sulfate, dimethyl sulfoxide and hexamethylphosphoric triamide;
the mass ratio of the m-phenylenediamine to the sodium dodecyl sulfate to the dimethyl sulfoxide to the hexamethylphosphoric triamide is 1:0.01 to 0.05:4 to 6:2 to 2.5.
Preferably, the step a), the preliminary dry absorption by vacuum water absorption includes:
placing on a vacuum water absorption plate for primary drying and absorption;
the vacuum degree of the vacuum water absorption plate is-5 to-15 KPa;
the temperature for drying again is 40 to 60 ℃.
Preferably, in step B), said acid chlorides comprise trimesoyl chloride and/or adipoyl chloride;
the organic solvent comprises at least one of n-hexane, isopar G and Isopar L;
in the oil phase solution, the mass content of acyl chloride is 0.1-0.2 wt%;
coating the oil phase solution on the base film obtained in the step A) in an amount of 20 to 50 g/m 2 。
Preferably, in the step C), the air inlet speed in the first hot air environment is 600 to 800 fpm, and the hot air humidity is 60 to 80 percent RH;
the time of the first reaction is 1 to 3min.
Preferably, in the step D), the air inlet speed in the second hot air environment is 300 to 500 fpm, and the hot air humidity is 20 to 40 percent RH;
the time of the second reaction is 1 to 3min.
Preferably, in the step E), the air inlet speed in the third hot air environment is 1000 to 1500 fpm, the hot air humidity is 40% RH to 60% RH;
the time of the third reaction is 0.5 to 1.5 min.
Preferably, in step E), after the third reaction is completed, the method further comprises: rinsing;
the rinsing comprises:
a) Rinsing with an aqueous solution of sodium hydroxide at a temperature of 25 to 35 ℃ and a pH value of 11.5 to 12.5 for 0.5 to 1min;
b) Rinsing with an IPA aqueous solution with the temperature of 35-45 ℃ and the mass concentration of 20-30% for 4-5min;
c) Rinsing with an IPA aqueous solution with the temperature of 25-35 ℃ and the mass concentration of 20-30% for 0.5-1min;
d) Rinsing for 4 to 5min by using an IPA aqueous solution with the temperature of 35 to 45 ℃ and the mass concentration of 20 to 30 percent; e) Rinsing with RO water at the temperature of 25-35 ℃ for 0.5-1min;
f) Rinsing for 2 to 3min by using a glycerol aqueous solution with the temperature of 25 to 35 ℃ and the mass concentration of 4 to 5 percent;
after the rinsing, the method further comprises the following steps: coating PVA solution and stoving.
The invention also provides a reverse osmosis membrane prepared by the preparation method.
The invention provides a preparation method of a reverse osmosis membrane, which comprises the following steps: a) Soaking the basement membrane in the aqueous phase solution, taking out, performing primary drying and absorption through vacuum water absorption, and then drying again; the aqueous phase solution comprises polyamine monomers and additives; b) Coating an oil phase solution on the basement membrane obtained in the step A); the oil phase solution comprises acyl chloride and an organic solvent; c) Carrying out a first reaction on the membrane obtained in the step B) in a first hot air environment; the temperature of the first reaction is 70 to 100 ℃; d) Carrying out a second reaction on the membrane obtained in the step C) in a second hot air environment; the temperature of the second reaction is 50 to 70 ℃; e) Carrying out a third reaction on the membrane obtained in the step D) in a third hot air environment to obtain a reverse osmosis membrane completely reacted; the temperature of the third reaction is 10 to 20 ℃. The basement membrane coated with the oil phase solution in the steps is sequentially reacted in three hot air environments, and in the first hot air environment, redundant oil phase solvent is mainly dried and subjected to a cross-linking reaction; mainly further crosslinking reaction in a second hot air environment; in the third hot air environment, the structure is mainly stabilized and shaped after the cross-linking reaction. The steps can interact well, and the finally prepared reverse osmosis membrane has excellent membrane flux and membrane desalination rate.
Detailed Description
The technical solutions of the present invention will be described clearly and completely below with reference to embodiments of the present invention, and it should be apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The invention provides a preparation method of a reverse osmosis membrane, which comprises the following steps:
a) Soaking the basement membrane in the aqueous phase solution, taking out, performing primary drying and absorption through vacuum water absorption, and then drying again; the aqueous phase solution comprises polyamine monomers and additives;
b) Coating an oil phase solution on the basement membrane obtained in the step A); the oil phase solution comprises acyl chloride and an organic solvent;
c) Carrying out a first reaction on the membrane obtained in the step B) in a first hot air environment; the temperature of the first reaction is 70 to 100 ℃;
d) Carrying out a second reaction on the membrane obtained in the step C) in a second hot air environment; the temperature of the second reaction is 50 to 70 ℃;
e) Carrying out a third reaction on the membrane obtained in the step D) in a third hot air environment to obtain a reverse osmosis membrane completely reacted; the temperature of the third reaction is 10 to 20 ℃.
In step A):
soaking the basement membrane in the aqueous phase solution, taking out, performing primary drying and absorption through vacuum water absorption, and then drying again; the aqueous phase solution includes polyamine monomers and additives.
In some embodiments of the present invention, the base film comprises polysulfone nonwoven fabric, which may be generally commercially available.
In certain embodiments of the present invention, the polyamine monomer comprises m-phenylenediamine. The additive comprises at least one of sodium dodecyl sulfate, dimethyl sulfoxide and hexamethylphosphoric triamide; specifically, the additives include sodium lauryl sulfate, dimethyl sulfoxide, and hexamethylphosphoric triamide. The mass ratio of the polyamine monomer to the additive is 1:6.01 to 8.55.
In certain embodiments of the invention, the aqueous phase solution comprises m-phenylenediamine, sodium dodecyl sulfate, dimethyl sulfoxide, and hexamethylphosphoric triamide in a mass ratio of 1:0.01 to 0.05:4 to 6:2 to 2.5; specifically, it may be 1:0.02:5:2.2.
in certain embodiments of the present invention, the aqueous phase solution comprises water, meta-phenylenediamine, sodium dodecyl sulfate, dimethyl sulfoxide, hexamethylphosphoric triamide, and a pH adjuster. The water is pure water, which may be tap water produced by filtration through a reverse osmosis membrane element. In the aqueous phase solution, the mass content of water is 80-90%, specifically 85%. The pH regulator is sodium hydroxide and/or camphorsulfonic acid. In certain embodiments, the pH adjusting agent is sodium hydroxide and camphorsulfonic acid in a mass ratio of 0.175:1.
in certain embodiments of the present invention, the method of preparing the aqueous phase solution comprises:
uniformly mixing water, m-phenylenediamine, sodium dodecyl sulfate, dimethyl sulfoxide and hexamethyl phosphoric triamide, and adding a pH regulator to regulate the pH value to 7.6-8 to obtain an aqueous phase solution.
In certain embodiments, a pH adjuster is added to adjust the pH to 7.8.
In some embodiments of the invention, the soaking time of the base film in the aqueous phase solution is 30 to 60 s; specifically, it may be 40 s.
In certain embodiments of the present invention, the preliminary dry absorption by vacuum water absorption comprises:
placing on a vacuum water absorption plate for primary drying and absorption.
The vacuum degree of the vacuum water absorption plate is-5 to-15 KPa, and specifically can be-10 KPa; the time for the initial drying and absorption is 10 to 30 s, and specifically can be 20 s. The absorption under vacuum conditions ensures that the aqueous solution is sufficiently impregnated into the polysulfone layer.
In certain embodiments of the invention, the temperature for drying again is 40 to 60 ℃; specifically, it may be 50 ℃. The re-drying is carried out on a heated roller.
In step B):
coating an oil phase solution on the basement membrane obtained in the step A); the oil phase solution comprises acyl chloride and an organic solvent.
In certain embodiments of the present invention, the acid chlorides include trimesoyl chloride and/or adipoyl chloride; trimesoyl chloride is preferred. The organic solvent comprises at least one of n-hexane, isopar G and Isopar L; isopar G is preferred. In the oil phase solution, the mass content of acyl chloride is 0.1-0.2 wt%; specifically, it may be 0.15 wt%.
In certain embodiments of the present invention, the method of preparing the oil phase solution comprises:
and mixing acyl chloride and an organic solvent uniformly to obtain an oil phase solution.
In some embodiments of the invention, the coating amount of the oil phase solution on the base film obtained in the step A) is 20 to 50 g/m 2 (ii) a Specifically, it may be 30 g/m 2 。
In step C):
carrying out a first reaction on the membrane obtained in the step B) in a first hot air environment; the temperature of the first reaction is 70 to 100 ℃.
In some embodiments of the invention, the air intake speed in the first hot air environment is 600 to 800 fpm, specifically 700 fpm, 800 fpm or 600 fpm; the hot air humidity is 60% RH to 80% RH, specifically 70% RH, 80% RH or 60% RH; the air exhaust speed in the first hot air environment is 550-750 fpm, and specifically, the air exhaust speed in the first hot air environment can be 650 fpm, 750 fpm or 550 fpm. The temperature of the first reaction is 90 ℃, 100 ℃ or 70 ℃; the time is 1 to 3min, specifically, 2 min.
In certain embodiments of the invention, the first reaction is carried out in a first oven.
The first hot air environment is mainly used for drying the redundant oil phase solvent, so the heat treatment temperature is higher; meanwhile, the heat treatment humidity is higher, and flux loss caused by collapse of micropores of the polysulfone ultrafiltration basement membrane at high temperature is avoided.
In step D):
carrying out a second reaction on the membrane obtained in the step C) in a second hot air environment; the temperature of the second reaction is 50 to 70 ℃.
In some embodiments of the invention, the air intake speed in the second hot air environment is 300 to 500 fpm, specifically 400 fpm, 500 fpm or 300 fpm; the hot air humidity is 20% RH to 40% RH, specifically 30% RH, 40% RH or 20% RH; the air exhaust speed in the second hot air environment is 250-450 fpm, and specifically can be 350 fpm, 450 fpm or 250 fpm. The temperature of the second reaction is 60 ℃, 70 ℃ or 50 ℃; the time is 1 to 3min, specifically, 2 min.
In certain embodiments of the present invention, the second reaction is carried out in a second oven.
The second hot air environment is mainly used for the cross-linking reaction, and because no excess oil phase solvent exists in the process, the heat treatment temperature is obviously reduced, and poor film forming caused by high temperature is avoided; meanwhile, the lower heat treatment humidity is used in the stage, so that the hydrolysis of acyl chloride in a high-humidity environment is avoided.
In step E):
carrying out a third reaction on the membrane obtained in the step D) in a third hot air environment to obtain a reverse osmosis membrane completely reacted; the temperature of the third reaction is 10 to 20 ℃.
In some embodiments of the invention, the air intake speed in the third hot air environment is 1000 to 1500 fpm, specifically 1200 fpm, 1500 fpm, or 1000 fpm; the hot air humidity is 40% RH to 60% RH, specifically 50% RH, 60% RH or 40% RH; the air exhaust speed in the third hot air environment is 950 to 1450 fpm, specifically 1200 fpm, 1150 fpm or 950 fpm. The temperature of the third reaction is 15 ℃, 20 ℃ or 10 ℃, and the time is 0.5 to 1.5 min.
In certain embodiments of the present invention, the third reaction is carried out in a third oven.
The third hot air environment is low-temperature treatment, and the stable structure of the reaction layer is mainly ensured by rapid cooling; and meanwhile, the environmental humidity is improved, and the collapse of micropores of the membrane is slowed down. Finally ensuring that the membrane flux is not greatly lost in the subsequent rinsing process.
In certain embodiments of the present invention, after the third reaction is completed, the method further comprises: and (6) rinsing.
The rinsing comprises the following steps:
a) Rinsing with an aqueous solution of sodium hydroxide at a temperature of 25-32 ℃ and a pH value of 11.5-12.5 for 0.5-1min;
b) Rinsing with an IPA aqueous solution with the temperature of 35-45 ℃ and the mass concentration of 20-30% for 4-5min;
c) Rinsing with an IPA aqueous solution with the temperature of 25-32 ℃ and the mass concentration of 20-30% for 0.5-1min;
d) Rinsing with an IPA aqueous solution with the temperature of 35-45 ℃ and the mass concentration of 20-30% for 4-5min; e) Rinsing with RO water at the temperature of 25 to 35 ℃ for 0.5 to 1min;
f) Rinsing for 2-3min by using a glycerol water solution with the temperature of 25-35 ℃ and the mass concentration of 4-5%.
In certain embodiments of the invention, in step a), the aqueous solution of sodium hydroxide is at a temperature of 30 ℃ and a pH of 12; the rinsing time is 1min.
In certain embodiments of the invention, in step b), the temperature of the aqueous IPA solution is 38 ℃ and the mass concentration is 25%; the rinsing time was 4min.
In certain embodiments of the present invention, in step c), the temperature of the aqueous IPA solution is 30 ℃ and the mass concentration is 25%; the rinsing time is 1min.
In certain embodiments of the invention, in step d), the temperature of the aqueous IPA solution is 40 ℃ and the mass concentration is 25%; the rinsing time was 4min.
In certain embodiments of the invention, in step e), the temperature of the RO water is 30 ℃; the rinsing time is 1min. The RO water is produced by filtering tap water through a reverse osmosis membrane element.
In certain embodiments of the invention, in step f), the temperature of the aqueous glycerol solution is 30 ℃ and the mass concentration is 4%; the rinsing time is 3min.
In some embodiments of the present invention, after the rinsing, the method further comprises: coating PVA water solution and drying to obtain the reverse osmosis membrane with the protective layer. The mass concentration of the PVA aqueous solution is 3-5%; specifically, it may be 4%. The PVA aqueous solution is coated on the surface coated with the oil phase solution, so that a protective layer can be formed on the surface of the film, and physical damage is reduced. In the reverse osmosis membrane, the thickness of the protective layer is 100 to 300 nm.
The invention also provides a reverse osmosis membrane prepared by the preparation method.
The source of the raw materials used in the present invention is not particularly limited, and the raw materials may be those generally commercially available.
In order to further illustrate the present invention, a reverse osmosis membrane and a method for preparing the same according to the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.
The reagents used in the following examples are all commercially available.
Examples 1 to 6 and comparative examples 1 to 7
The aqueous phase solution comprises pure water, m-phenylenediamine, sodium dodecyl sulfate, dimethyl sulfoxide, hexamethyl phosphoric triamide and a pH regulator; the mass ratio of the m-phenylenediamine to the sodium dodecyl sulfate to the dimethyl sulfoxide to the hexamethyl phosphoric triamide is 1:0.02:5:2.2; in the aqueous phase solution, the mass content of pure water is 85%; the pH regulator is sodium hydroxide and camphorsulfonic acid, and the mass ratio of the sodium hydroxide to the camphorsulfonic acid is 0.175:1.
the preparation method of the aqueous phase solution comprises the following steps:
and (3) uniformly mixing RO water, m-phenylenediamine, sodium dodecyl sulfate, dimethyl sulfoxide and hexamethyl phosphoric triamide, and adding a pH regulator to regulate the pH value to 7.8 to obtain an aqueous phase solution.
The oil phase solution comprises trimesoyl chloride and Isopar G, and the mass content of the acyl chloride is 0.15 wt%;
the preparation method of the oil phase solution comprises the following steps:
and (3) uniformly mixing trimesoyl chloride and Isopar G to obtain an oil phase solution.
A preparation method of a reverse osmosis membrane comprises the following steps:
1) Soaking a polysulfone non-woven fabric basement membrane in the aqueous phase solution for 40 s, taking out, placing on a vacuum water absorption plate, performing primary drying and absorption for 20 s under the vacuum degree of-10 KPa, and then drying again on a heating roller at 50 ℃;
2) Coating an oil phase solution on the polysulfone non-woven fabric basement membrane obtained in the step 1) to obtain a membrane subjected to primary reaction; application of the oil phase solutionThe amount is 30 g/m 2 ；
3) Reacting the membrane obtained in the step 2) in a hot air environment in a first oven for 2 min;
4) Reacting the membrane obtained in the step 3) in a hot air environment in a second oven for 2 min;
5) Reacting the membrane obtained in the step 4) in a hot air environment in a third oven for 1min;
6) Rinsing:
6-1) rinsing with 30 deg.C aqueous solution of sodium hydroxide with pH of 12 for 1min;
6-2) rinsing with 25% IPA water solution at 38 deg.C for 4min;
6-3) rinsing with 25% IPA water solution at 30 deg.C for 1min;
6-4) rinsing with 25% IPA water solution at 40 deg.C for 4min;
6-5) rinsing with RO water at 30 deg.C for 1min;
6-6) rinsing with 4% glycerol water solution at 30 deg.C for 3min;
7) And coating a PVA aqueous solution with the mass concentration of 4% on one surface of the membrane coated with the oil phase solution, and drying to obtain the reverse osmosis membrane containing the protective layer. In the reverse osmosis membrane, the thickness of a protective layer is 100 to 300 nm.
The temperature, humidity, air inlet speed and air outlet speed of hot air in the ovens of examples 1 to 6 and comparative examples 1 to 7 are shown in Table 1.
TABLE 1 temperature, humidity, wind speed, and wind speed of air to be blown out of each oven of examples 1 to 6 and comparative examples 1 to 7
According to the standard GB/T32373-2015, the membrane flux and the salt rejection of the reverse osmosis membranes obtained in the examples 1 to 6 and the comparative examples 1 to 7 are shown in the table 2.
TABLE 2 Performance of reverse osmosis membranes obtained in examples 1 to 6 and comparative examples 1 to 7
As can be seen from Table 2, the reverse osmosis membrane prepared by the invention has the membrane flux of not less than 31.9 GFD and the salt rejection rate of not less than 99.25%.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A preparation method of a reverse osmosis membrane is characterized by comprising the following steps:
a) Soaking the basement membrane in the aqueous phase solution, taking out, performing primary drying and absorption through vacuum water absorption, and then drying again; the aqueous phase solution comprises polyamine monomers and additives;
b) Coating an oil phase solution on the basement membrane obtained in the step A); the oil phase solution comprises acyl chloride and an organic solvent;
c) Carrying out a first reaction on the membrane obtained in the step B) in a first hot air environment; the temperature of the first reaction is 70 to 100 ℃;
d) Carrying out a second reaction on the membrane obtained in the step C) in a second hot air environment; the temperature of the second reaction is 50 to 70 ℃;
e) Carrying out a third reaction on the membrane obtained in the step D) in a third hot air environment to obtain a reverse osmosis membrane; the temperature of the third reaction is 10 to 20 ℃.
2. The method according to claim 1, wherein in step a), the base film comprises polysulfone nonwoven fabric.
3. The method according to claim 1, wherein in step a), the polyamine monomer comprises m-phenylenediamine;
the additive comprises sodium dodecyl sulfate, dimethyl sulfoxide and hexamethylphosphoric triamide;
the mass ratio of the m-phenylenediamine to the sodium dodecyl sulfate to the dimethyl sulfoxide to the hexamethylphosphoric triamide is 1:0.01 to 0.05:4 to 6:2 to 2.5.
4. The method according to claim 1, wherein the preliminary drying absorption by vacuum water absorption in the step a) comprises:
placing on a vacuum water absorption plate for primary drying and absorption;
the vacuum degree of the vacuum water absorption plate is-5 to-15 KPa;
the temperature for drying again is 40 to 60 ℃.
5. The process according to claim 1, wherein in step B), the acid chloride comprises trimesoyl chloride and/or adipoyl chloride;
the organic solvent comprises at least one of n-hexane, isopar G and Isopar L;
in the oil phase solution, the mass content of acyl chloride is 0.1-0.2 wt%;
coating the oil phase solution on the base film obtained in the step A) in an amount of 20 to 50 g/m 2 。
6. The method according to claim 1, wherein in step C), the wind speed of the wind in the first hot air environment is 600 to 800 fpm, and the hot air humidity is 60% RH to 80% RH;
the time of the first reaction is 1 to 3min.
7. The method according to claim 1, wherein in step D), the wind speed of the wind in the second hot air environment is 300 to 500 fpm, and the hot air humidity is 20% RH to 40% RH;
the time of the second reaction is 1 to 3min.
8. The method according to claim 1, wherein in step E), the wind speed of the wind in the third hot air environment is 1000 to 1500 fpm, and the hot air humidity is 40% RH to 60% RH;
the time of the third reaction is 0.5 to 1.5 min.
9. The method according to claim 1, wherein the step E) further comprises, after the third reaction is completed: rinsing;
the rinsing comprises:
a) Rinsing with an aqueous solution of sodium hydroxide at a temperature of 25-35 ℃ and a pH value of 11.5-12.5 for 0.5-1min;
b) Rinsing for 4 to 5min by using an IPA aqueous solution with the temperature of 35 to 45 ℃ and the mass concentration of 20 to 30 percent;
c) Rinsing with an IPA aqueous solution with the temperature of 25-35 ℃ and the mass concentration of 20-30% for 0.5-1min;
d) Rinsing for 4 to 5min by using an IPA aqueous solution with the temperature of 35 to 45 ℃ and the mass concentration of 20 to 30 percent; e) Rinsing with RO water at the temperature of 25-35 ℃ for 0.5-1min;
f) Rinsing for 2 to 3min by using a glycerol aqueous solution with the temperature of 25 to 35 ℃ and the mass concentration of 4 to 5 percent;
after the rinsing, the method further comprises the following steps: coating PVA solution and stoving.
10. A reverse osmosis membrane prepared by the preparation method according to any one of claims 1 to 9.
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| CN85107013A (en) * | 1984-09-27 | 1987-04-01 | 纳幕尔杜邦公司 | The multistage annealing of aramide reverse osmosis membranes |
| US7001518B1 (en) * | 2000-11-28 | 2006-02-21 | Hydranautics | Low pressure reverse osmosis and nanofiltration membranes and method for the production thereof |
| JP4656502B2 (en) * | 2004-10-01 | 2011-03-23 | 日東電工株式会社 | Composite semipermeable membrane and method for producing the same |
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| KR101653414B1 (en) * | 2010-09-13 | 2016-09-01 | 주식회사 효성 | Method for Manufacturing Polyamide-based Reverse Osmosis Membrane having Antifouling Property |
| JP2012210607A (en) * | 2011-03-31 | 2012-11-01 | Ibiden Co Ltd | Polyimide asymmetrical hollow fiber membrane |
| CN103933881B (en) * | 2013-01-18 | 2016-10-05 | 中国科学院宁波材料技术与工程研究所 | A kind of method using interfacial polymerization to prepare composite nanometer filtering film |
| CN107349804A (en) * | 2017-07-13 | 2017-11-17 | 中国科学院生态环境研究中心 | A kind of preparation method of high flux anti-acid NF membrane |
| CN113368713B (en) * | 2021-08-12 | 2021-11-12 | 湖南沁森高科新材料有限公司 | Preparation process of nanofiltration composite membrane |
| CN114950150B (en) * | 2022-07-19 | 2022-12-13 | 湖南沁森高科新材料有限公司 | Extremely-low-pressure reverse osmosis membrane and preparation method thereof |
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