CN108854573B - Hydrophilic modification method of separation membrane - Google Patents
Hydrophilic modification method of separation membrane Download PDFInfo
- Publication number
- CN108854573B CN108854573B CN201810792679.0A CN201810792679A CN108854573B CN 108854573 B CN108854573 B CN 108854573B CN 201810792679 A CN201810792679 A CN 201810792679A CN 108854573 B CN108854573 B CN 108854573B
- Authority
- CN
- China
- Prior art keywords
- membrane
- instrument
- polymerization reaction
- liquid level
- plasma
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0006—Organic membrane manufacture by chemical reactions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/76—Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74
- B01D71/78—Graft polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/02—Hydrophilization
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/38—Graft polymerization
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/36—Hydrophilic membranes
Abstract
The invention discloses a hydrophilic modification method of a separation membrane, which comprises the following steps: firstly, placing a membrane on a sample table of an LB membrane instrument, dropwise adding an amphiphilic molecular solution into a water tank of the LB membrane instrument to form a orderly-arranged monomolecular layer, detecting membrane pressure, adjusting the positions of two liquid level baffles of the LB membrane instrument at a moving speed of 0.5-10 mm/s, adjusting the moving speed of the liquid level baffles of the LB membrane instrument to 90-500 mu m/s when the membrane pressure reaches a critical value, and vertically immersing the membrane below the liquid level of the LB membrane instrument at a descending speed of 90-500 mu m/s to uniformly adhere a layer of regularly-arranged amphiphilic molecular membrane on the surface of the membrane; and secondly, transferring the membrane obtained in the step one to a polymerization reaction device, and carrying out monomer polymerization reaction on the surface of the membrane under a liquid phase condition to obtain the modified membrane with the surface grafted with hydrophilic groups and polymers. The invention has important significance for improving the performances of membrane flux, pollution resistance, membrane life and the like.
Description
Technical Field
The invention relates to a modification method of a separation membrane, in particular to a hydrophilic modification method of the separation membrane.
Background
The polytetrafluoroethylene, polyvinylidene fluoride and other materials have the advantages of corrosion resistance, heat resistance, cold resistance and the like, and have excellent comprehensive indexes in all aspects and good film forming effect.
With the development of water treatment industry, membrane treatment is one of the important processes for producing high quality water, but many materials suitable for membrane formation have poor hydrophilicity or poor effect of direct water treatment, such as polytetrafluoroethylene, and the contact angle of membrane formation is as high as 133 degrees, which is limited by poor hydrophilicity and is difficult to be directly applied to the field of water treatment.
The methods for improving the hydrophilicity of the membrane are not limited, and include chemical surface treatment modification, high-energy radiation grafting modification, blending modification and the like, but the methods often have the defects of complex treatment method, high equipment requirement, more byproducts and the like. Plasma grafting modification is favored by some researchers, but fails to effectively solve the problem of modification timeliness.
Therefore, the method for modifying the membrane with good timeliness has great significance for the water treatment industry, and the hydrophilicity of the membrane can be effectively improved, the pollution of the membrane can be reduced.
Disclosure of Invention
In order to further improve the hydrophilicity of a membrane material on the basis of the prior art and overcome the common problem of timeliness in membrane hydrophilic modification, thereby improving the membrane flux, the membrane filtration effect and the membrane service life, the invention provides a novel hydrophilic modification method of a separation membrane.
The purpose of the invention is realized by the following technical scheme:
a method for hydrophilic modification of a separation membrane, comprising the steps of:
first, grafting amphiphilic molecules on the surface of the membrane
Placing a membrane on a sample table of an LB membrane instrument, dropwise adding an amphiphilic molecular solution into a water tank of the LB membrane instrument to form a orderly-arranged monomolecular layer, detecting membrane pressure, adjusting the positions of two liquid level baffles of the LB membrane instrument at a moving speed of 0.5-10 mm/s, adjusting the moving speed of the liquid level baffles of the LB membrane instrument to 90-500 mu m/s when the membrane pressure reaches a critical value, vertically immersing the membrane below the liquid level of the LB membrane instrument at a descending speed of 90-500 mu m/s, and uniformly attaching a layer of regularly-arranged amphiphilic molecular membrane on the surface of the membrane;
secondly, carrying out the monomer polymerization reaction on the surface of the membrane in a liquid phase
And (3) transferring the membrane obtained in the step one to a polymerization reaction device, and carrying out monomer polymerization reaction on the surface of the membrane under the anhydrous and oxygen-free liquid phase condition to obtain the modified membrane with the surface grafted with hydrophilic groups and polymers.
Thirdly, a subsequent grafting reaction step:
and (4) placing the modified membrane with the surface grafted with the hydrophilic group and the polymer obtained in the step two into a plasma instrument for plasma treatment.
In the invention, in the first step, the membrane is a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane with the aperture of 0.0002-1 mu m.
In the invention, the membrane component in the first step at least contains one of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polysulfone membrane and polyimide.
In the present invention, the first step may be preceded by a film pretreatment process in which the film material is subjected to plasma treatment using nitrogen and/or argon. The pretreatment step causes a large amount of free radicals to be generated on the surface of the membrane, which can serve as initiation conditions for the polymerization reaction in the second step.
In the invention, the plasma treatment time is 10-300 s, and the plasma electron energy is 2-6 ev.
In the invention, in the first step, the amphiphilic molecule solution is an acrylic acid solution, and the content of acrylic acid is 5-40 wt%.
In the invention, the liquid phase in the second step is a solution containing an initiator, wherein: the initiator can be azodiisobutyronitrile, and the content is 0.01-1 wt%; if the molecular length of the polyacrylic acid is enhanced, the content of the initiator is properly reduced; the solvent may be chloroform.
In the present invention, the liquid phase in the second step may contain a molecular weight regulator, wherein: the molecular weight regulator can be ethylene glycol dimethacrylate, and the concentration of the ethylene glycol dimethacrylate is 0.1-20 wt% of the liquid phase.
In the invention, in the second step, a low temperature is used for providing a reaction termination condition for the thermal polymerization reaction system, and the low temperature is between 277.15 and 0K.
In the invention, the treatment temperature of the polymerization reaction in the step two is more than or equal to 45 ℃, and the treatment time is more than or equal to 2 h.
The invention has the following advantages:
according to the invention, by utilizing the combination of the LB membrane method and the liquid phase polymerization reaction, as shown in figure 1, regularly arranged amphiphilic molecules are firstly grafted on the surface of the membrane material, and then the liquid phase polymerization reaction is utilized to form a polymer with uniform thickness and firm adhesion on the surface of the membrane material, so that the hydrophilicity of the membrane material is greatly improved, the water contact angle of the surface of the modified polytetrafluoroethylene membrane is reduced from 133 degrees to 81 degrees, and the water contact angle of the surface of the polyvinylidene fluoride membrane is reduced from 92 degrees to 76 degrees. Has important significance for improving the performances of membrane flux, pollution resistance, membrane life and the like.
Drawings
FIG. 1 is a schematic view of the hydrophilic modification of the separation membrane of the present invention.
Detailed Description
The technical solution of the present invention is further described below with reference to the accompanying drawings, but the present invention is not limited thereto, and modifications or equivalent substitutions may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention.
Example 1
The embodiment provides a hydrophilic modification method of a membrane, which mainly comprises the following steps:
firstly, a pretreatment step:
(1) washing a polytetrafluoroethylene membrane by using deionized water, soaking the polytetrafluoroethylene membrane in acetone, carrying out ultrasonic treatment for 2 hours at the power of 100W and the temperature of 30 ℃, transferring the membrane to an oven (80 ℃) for drying for 2 hours, and then drying the membrane in a vacuum drying oven (22 ℃) for 3 hours;
(2) opening a plasma cavity, mounting the two electrode plates on corresponding hangers at an interval of 5cm, placing the cleaned PTFE film sample in the center of the grounding electrode plate, and then closing and locking the cavity;
(3) starting an AP-600 plasma instrument, preheating for 5-10 min, opening a plasma gas valve, and starting a gas pump and a vacuum pump;
(4) starting a vacuum pump on an operation panel for vacuum pumping, and simultaneously setting the type of plasma gas required by processing a sample to be nitrogen, the processing power to be 50W and the time to be 50 s;
(5) when the air pressure in the cavity is lower than 40Pa, the vacuum pumping is stopped, plasma gas is put in, the flow is adjusted to ensure that the plasma pressure in the cavity is stabilized at 100mTorr, a discharge program is started, and plasma is generated in the cavity to process a sample.
Secondly, grafting amphiphilic molecules on the surface of the membrane:
placing the membrane obtained in the step one on a sample table of an LB membrane instrument, dropwise adding an amphiphilic molecular solution into a water tank of the LB membrane instrument, detecting membrane pressure, and adjusting the positions of two liquid level baffles of the LB membrane instrument at a moving speed of 1-5 mm/s; when the membrane pressure reaches a critical value, the moving speed of a liquid level baffle of the LB membrane instrument is adjusted to be 120 mu m/s, and the membrane is vertically immersed below the liquid level of the LB membrane instrument at the descending speed of 120 mu m/s, so that a layer of amphiphilic molecular membrane is uniformly attached to the surface of the membrane.
Thirdly, carrying out monomer polymerization reaction on the surface of the membrane in a liquid phase:
accurately weighing 6.280g of ethylene glycol dimethacrylate into 40mL of chloroform, uniformly mixing, adding 0.128g of azobisisobutyronitrile, uniformly mixing, transferring into a reaction kettle, transferring the modified film with the acrylic LB film attached to the surface obtained in the step two into the reaction kettle, vacuumizing, introducing nitrogen, sealing after repeating for three times, placing in a water bath at 60 ℃ for reacting for 24 hours, taking out the reaction kettle, and placing in an ice salt bath to terminate the reaction. And washing the modified membrane with toluene, absolute ethyl alcohol and deionized water in sequence to remove redundant acrylic acid, carrying out vacuum drying for 24 hours at 110 ℃ to obtain the hydrophilic modified separation membrane with the surface grafted with hydrophilic groups and polymers, and storing in the deionized water.
Fourthly, a subsequent grafting reaction step:
and (3) placing the hydrophilic modified membrane obtained in the step three in the plasma instrument in the step one, and adjusting the type of the plasma gas to be nitrogen, the processing power to be 50W and the time to be 300 s.
In this embodiment, the pore size of the polytetrafluoroethylene membrane is 0.3 μm.
In this embodiment, the amphiphilic molecule solution is an acrylic acid solution, wherein: the solvent was chloroform, and the acrylic acid content was 3.5 wt%.
The water contact angle of the surface of the modified polytetrafluoroethylene membrane is reduced from 133 degrees to 81 degrees.
Example 2
The difference between the embodiment and the embodiment 1 is that a polyvinylidene fluoride membrane with the pore size of 0.25 mu m is used as a hydrophilic modification object, and the water contact angle of the surface of the polyvinylidene fluoride membrane is reduced from 92 degrees to 76 degrees after modification.
Example 3
The difference between this embodiment and embodiment 1 is that in step one, argon plasma is used for pretreatment, the processing power is adjusted to 100W, the plasma pressure in the chamber is 200mTorr, and the processing time is 50 s.
Example 4
The difference between this example and example 1 is that argon plasma is used in the fourth step for further modification, the processing power is adjusted to 100W, the pressure of plasma in the chamber is 200mTorr, and the processing time is 300 s.
Example 5
This example differs from example 1 in that there is no pretreatment step. The water contact angle of the surface of the modified polytetrafluoroethylene membrane is reduced from 133 degrees to 83 degrees.
Example 6
This example differs from example 1 in that there is no subsequent grafting step. The water contact angle of the surface of the modified polytetrafluoroethylene membrane is reduced from 133 degrees to 84 degrees.
Claims (8)
1. A method for hydrophilic modification of a separation membrane, characterized in that the method comprises the steps of:
first, grafting amphiphilic molecules on the surface of the membrane
Placing a membrane on a sample table of an LB membrane instrument, dropwise adding an amphiphilic molecular solution into a water tank of the LB membrane instrument to form a orderly-arranged monomolecular layer, detecting membrane pressure, adjusting the positions of two liquid level baffles of the LB membrane instrument at a moving speed of 0.5-10 mm/s, adjusting the moving speed of the liquid level baffles of the LB membrane instrument to 90-500 mu m/s when the membrane pressure reaches a critical value, vertically immersing the membrane below the liquid level of the LB membrane instrument at a descending speed of 90-500 mu m/s, and uniformly attaching a layer of regularly-arranged amphiphilic molecular membrane on the surface of the membrane;
secondly, carrying out the monomer polymerization reaction on the surface of the membrane in a liquid phase
Transferring the membrane obtained in the step one to a polymerization reaction device, and carrying out monomer polymerization reaction on the surface of the membrane under the anhydrous and oxygen-free liquid phase condition to obtain a modified membrane with the surface grafted with hydrophilic groups and polymers;
thirdly, a subsequent grafting reaction step:
placing the modified membrane with the surface grafted with the hydrophilic group and the polymer obtained in the step two in a plasma instrument for plasma treatment;
the membrane is subjected to the following pretreatment procedure before being subjected to amphiphilic molecule grafting: the film is plasma treated using nitrogen and/or argon.
2. The hydrophilic modification method of a separation membrane according to claim 1, characterized in that the membrane is a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane, the pore size is 0.0002 to 1 μm, and the membrane component contains at least one of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polysulfone and polyimide.
3. The method of claim 1, wherein the plasma treatment time is 10-300 s and the plasma electron energy is 2-6 eV during the pre-treatment and the subsequent grafting reaction.
4. The method of claim 1, wherein the amphiphilic molecule solution is an acrylic acid solution, and the content of acrylic acid is 5 to 40 wt%.
5. The method of claim 1, wherein the liquid phase contains an initiator, and the initiator is azobisisobutyronitrile, and the content of the initiator is 0.01 to 1 wt%.
6. The hydrophilic modification method of a separation membrane according to claim 5, wherein the liquid phase further contains a molecular weight regulator, the molecular weight regulator is ethylene glycol dimethacrylate, and the content of the ethylene glycol dimethacrylate is 0.1 to 20 wt%.
7. The method of claim 1, wherein the thermal polymerization system provides a termination condition for the polymerization reaction at a low temperature of 277.15-0K.
8. The method for hydrophilic modification of a separation membrane according to claim 1, wherein the polymerization reaction is carried out at a treatment temperature of 45 ℃ or more and for a treatment time of 2 hours or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810792679.0A CN108854573B (en) | 2018-07-18 | 2018-07-18 | Hydrophilic modification method of separation membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810792679.0A CN108854573B (en) | 2018-07-18 | 2018-07-18 | Hydrophilic modification method of separation membrane |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108854573A CN108854573A (en) | 2018-11-23 |
| CN108854573B true CN108854573B (en) | 2021-06-01 |
Family
ID=64303146
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810792679.0A Active CN108854573B (en) | 2018-07-18 | 2018-07-18 | Hydrophilic modification method of separation membrane |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108854573B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101890314A (en) * | 2010-07-20 | 2010-11-24 | 东华大学 | Surface hydrophilic modification method for polytetrafluoroethylene bulked membrane |
| CN103263861A (en) * | 2013-05-30 | 2013-08-28 | 哈尔滨工业大学 | Hydrophilic modification method for polyvinylidene fluoride hollow fiber membrane |
| CN103831027A (en) * | 2014-02-28 | 2014-06-04 | 东华大学 | Method for improving pollution resistance of PVDF (polyvinylidene fluoride) porous membrane based on plasmas technology |
| EP3088450A1 (en) * | 2015-04-30 | 2016-11-02 | VITO NV (Vlaamse Instelling voor Technologisch Onderzoek NV) | Plasma assisted hydrophilicity enhancement of polymer materials |
| CN106268370A (en) * | 2016-08-29 | 2017-01-04 | 同济大学 | Poly tetrafluoroethylene low temperature plasma hydrophilic modifying and timeliness modification processing method |
-
2018
- 2018-07-18 CN CN201810792679.0A patent/CN108854573B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101890314A (en) * | 2010-07-20 | 2010-11-24 | 东华大学 | Surface hydrophilic modification method for polytetrafluoroethylene bulked membrane |
| CN103263861A (en) * | 2013-05-30 | 2013-08-28 | 哈尔滨工业大学 | Hydrophilic modification method for polyvinylidene fluoride hollow fiber membrane |
| CN103831027A (en) * | 2014-02-28 | 2014-06-04 | 东华大学 | Method for improving pollution resistance of PVDF (polyvinylidene fluoride) porous membrane based on plasmas technology |
| EP3088450A1 (en) * | 2015-04-30 | 2016-11-02 | VITO NV (Vlaamse Instelling voor Technologisch Onderzoek NV) | Plasma assisted hydrophilicity enhancement of polymer materials |
| CN106268370A (en) * | 2016-08-29 | 2017-01-04 | 同济大学 | Poly tetrafluoroethylene low temperature plasma hydrophilic modifying and timeliness modification processing method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108854573A (en) | 2018-11-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4483901A (en) | Selectively gas-permeable composite membrane and process for production thereof | |
| CN107744727B (en) | Surface hydrophilic modification method of chloromethylated polyether sulfone ultrafiltration membrane | |
| Gil'Man | Low-temperature plasma treatment as an effective method for surface modification of polymeric materials | |
| CN107185417B (en) | Sulfonated polyether sulfone membrane and preparation method thereof, sulfonated polysulfone membrane and preparation method and application thereof | |
| CN111420559A (en) | Surface modification method of polymeric membrane based on dopamine | |
| CN110139719B (en) | Hydrophilic multifunctional ultrathin coating with excellent stability and durability | |
| CN108043246B (en) | Preparation method of super-hydrophilic organic membrane based on micro-nano structure surface imprinting | |
| CN108295667A (en) | A kind of positive osmosis composite membrane and preparation method thereof based on large aperture basement membrane | |
| CN109847602B (en) | Method for in-situ preparation of metal organic framework hybrid membrane and application of metal organic framework hybrid membrane | |
| CN113856492B (en) | Polyamide reverse osmosis membrane with molecular sieve doped porous supporting layer | |
| CN103861476A (en) | Preparation method of polyvinylidene fluoride (PVDF) composite mesoporous membrane | |
| CN1919429A (en) | Graft phenylethene modified film and preparation method and application thereof | |
| CN112940343A (en) | Enhanced perfluorinated sulfonic acid composite proton exchange membrane and production process thereof | |
| CN113231111A (en) | Side chain sulfonated polybenzimidazole composite cation exchange membrane and preparation method and application thereof | |
| CN108854573B (en) | Hydrophilic modification method of separation membrane | |
| Yu et al. | Surface modification of polypropylene macroporous membrane to improve its antifouling characteristics in a submerged membrane-bioreactor: H2O plasma treatment | |
| CN109267040B (en) | Acrylamide nano coating and preparation method thereof | |
| CN105233713B (en) | A kind of preparation method of the saturating alcohol composite membrane of infiltration evaporation | |
| CN107261863B (en) | Preparation method of anti-pollution polyvinyl chloride film | |
| EP0088515B1 (en) | Process for producing semipermeable membrane | |
| CN116212651A (en) | Super-hydrophilic ultrafiltration porous membrane and preparation method thereof | |
| Lin et al. | New Konjac Glucomannan‐PVA Composite Membrane for Application in Pervaporation Dehydration of Caprolactam Solution | |
| JP3668772B2 (en) | Separation membrane and manufacturing method thereof | |
| CN112823857A (en) | Preparation method of modified polypropylene film | |
| CN109894008A (en) | The modification of chloromethyl polyether sulfone/polyether sulfone copolymerization ultrafiltration membrane |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |