CN112973467B - Preparation method of composite nanofiltration membrane and composite nanofiltration membrane - Google Patents
Preparation method of composite nanofiltration membrane and composite nanofiltration membrane Download PDFInfo
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- 239000012528 membrane Substances 0.000 title claims abstract description 425
- 238000001728 nano-filtration Methods 0.000 title claims abstract description 90
- 239000002131 composite material Substances 0.000 title claims abstract description 76
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 273
- 229920000469 amphiphilic block copolymer Polymers 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 14
- 210000004379 membrane Anatomy 0.000 claims description 309
- 239000000243 solution Substances 0.000 claims description 134
- 239000012071 phase Substances 0.000 claims description 76
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 claims description 60
- 229920002492 poly(sulfone) Polymers 0.000 claims description 47
- UWCPYKQBIPYOLX-UHFFFAOYSA-N benzene-1,3,5-tricarbonyl chloride Chemical compound ClC(=O)C1=CC(C(Cl)=O)=CC(C(Cl)=O)=C1 UWCPYKQBIPYOLX-UHFFFAOYSA-N 0.000 claims description 31
- 229920002873 Polyethylenimine Polymers 0.000 claims description 30
- 238000001035 drying Methods 0.000 claims description 28
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 27
- 239000012074 organic phase Substances 0.000 claims description 19
- 229920002319 Poly(methyl acrylate) Polymers 0.000 claims description 15
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims description 14
- 239000004926 polymethyl methacrylate Substances 0.000 claims description 14
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 claims description 8
- 229940072049 amyl acetate Drugs 0.000 claims description 7
- PGMYKACGEOXYJE-UHFFFAOYSA-N anhydrous amyl acetate Natural products CCCCCOC(C)=O PGMYKACGEOXYJE-UHFFFAOYSA-N 0.000 claims description 7
- 239000008346 aqueous phase Substances 0.000 claims description 7
- MNWFXJYAOYHMED-UHFFFAOYSA-M heptanoate Chemical compound CCCCCCC([O-])=O MNWFXJYAOYHMED-UHFFFAOYSA-M 0.000 claims description 7
- 239000007864 aqueous solution Substances 0.000 claims description 6
- 210000002469 basement membrane Anatomy 0.000 claims description 6
- 239000002105 nanoparticle Substances 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 4
- 238000007654 immersion Methods 0.000 claims description 3
- -1 polytetrafluoroethylene Polymers 0.000 claims description 3
- 239000002904 solvent Substances 0.000 claims description 3
- 239000002033 PVDF binder Substances 0.000 claims description 2
- 239000004695 Polyether sulfone Substances 0.000 claims description 2
- IIEWJVIFRVWJOD-UHFFFAOYSA-N ethyl cyclohexane Natural products CCC1CCCCC1 IIEWJVIFRVWJOD-UHFFFAOYSA-N 0.000 claims description 2
- 238000005470 impregnation Methods 0.000 claims description 2
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 2
- 229920006393 polyether sulfone Polymers 0.000 claims description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 2
- 239000011259 mixed solution Substances 0.000 claims 1
- 238000004065 wastewater treatment Methods 0.000 claims 1
- 238000000926 separation method Methods 0.000 abstract description 61
- 238000012695 Interfacial polymerization Methods 0.000 abstract description 8
- 239000012798 spherical particle Substances 0.000 abstract description 3
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 88
- 230000004907 flux Effects 0.000 description 72
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 44
- 235000019341 magnesium sulphate Nutrition 0.000 description 44
- 238000012360 testing method Methods 0.000 description 44
- 238000002791 soaking Methods 0.000 description 43
- 238000010612 desalination reaction Methods 0.000 description 31
- 239000012510 hollow fiber Substances 0.000 description 25
- 238000000108 ultra-filtration Methods 0.000 description 25
- 229920001400 block copolymer Polymers 0.000 description 21
- 238000005406 washing Methods 0.000 description 6
- 239000000178 monomer Substances 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- CQNUVRLDYLUAJS-UHFFFAOYSA-N acetic acid;pentane Chemical compound CC(O)=O.CCCCC CQNUVRLDYLUAJS-UHFFFAOYSA-N 0.000 description 4
- 238000007664 blowing Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 238000001223 reverse osmosis Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 239000002086 nanomaterial Substances 0.000 description 2
- 239000012466 permeate Substances 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000008961 swelling Effects 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000006757 chemical reactions by type Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000011033 desalting Methods 0.000 description 1
- 239000003651 drinking water Substances 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 238000001471 micro-filtration Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920000768 polyamine Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920005629 polypropylene homopolymer Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000013102 re-test Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
Classifications
-
- 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
- B01D69/12—Composite membranes; Ultra-thin membranes
-
- 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
- B01D61/027—Nanofiltration
-
- 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
-
- 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
- B01D71/66—Polymers having sulfur in the main chain, with or without nitrogen, oxygen or carbon only
- B01D71/68—Polysulfones; Polyethersulfones
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
-
- 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
Abstract
The invention provides a preparation method of a composite nanofiltration membrane and the composite nanofiltration membrane prepared by the method. Through interfacial polymerization, amphiphilic block copolymer nano-scale spherical particles are contained in the generated nanofiltration membrane, so that the pollution resistance of the composite nanofiltration membrane is enhanced, higher water yield is obtained, and the problem that a membrane separation layer is easy to fall off is solved.
Description
Technical Field
The invention relates to a preparation method of a nanofiltration membrane, in particular to a preparation method of an anti-pollution composite nanofiltration membrane and the composite nanofiltration membrane.
Background
In recent years, membrane separation technology has been widely used in the fields of seawater purification, sewage control, and drinking water as a new and efficient means for separation, purification, and purification. Membrane materials that can be used in membrane separation techniques include microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, and reverse osmosis membranes, all of which have the property of passing a portion of the material and retaining a portion of the material. The nanofiltration membrane is a novel membrane material between the ultrafiltration membrane and the reverse osmosis membrane, and is characterized in that substances can selectively permeate through steric hindrance and electrostatic action to achieve the purpose of membrane separation, and the operating pressure condition is far lower than that of the reverse osmosis technology.
The main method for preparing the nanofiltration membrane is an interfacial polymerization method at present. The preparation of the hollow fiber nanofiltration membrane by the interfacial polymerization method is mainly characterized in that a dense separation layer is formed on a base membrane by the polymerization reaction of monomers in a water phase and an oil phase at an interface. The common interfacial polymerization reaction type takes polyamine as a water phase monomer and takes interfacial polymerization reaction with polyacyl chloride as an oil phase monomer. Compared with the traditional preparation method, the hollow fiber nanofiltration membrane can simultaneously obtain higher water flux and salt rejection rate because the ultrathin selection layer and the support layer can be respectively optimized.
However, the roughness of the membrane surface is usually increased during the interfacial polymerization process, so that the contaminants are easily attached to the membrane surface during the membrane separation process, and serious membrane pollution is caused. It is required to develop a new technology for reducing the surface contamination of the separation membrane.
Disclosure of Invention
In order to solve the technical problems, the invention provides a preparation method of a composite nanofiltration membrane and the composite nanofiltration membrane prepared by the method.
The embodiment of the invention provides a preparation method of a composite nanofiltration membrane, which comprises the following steps:
a. providing a base film;
b. providing an aqueous phase solution containing polyethyleneimine and piperazine, immersing a base membrane into the aqueous phase solution, taking out the base membrane, and draining to obtain the base membrane subjected to aqueous phase immersion;
c. providing a blended organic phase solution containing trimesoyl chloride and an amphiphilic block copolymer, immersing a base membrane after water phase immersion into the blended organic phase solution, and then taking out and drying to obtain the composite nanofiltration membrane.
In an implementable manner, the base membrane may be selected from one of a polysulfone membrane, a polyethersulfone membrane, a polyvinylidene fluoride membrane, a polyacrylonitrile membrane, and a polytetrafluoroethylene membrane. In one embodiment of the invention, the base membrane is a polysulfone hollow fiber ultrafiltration membrane.
In an achievable manner, the mass concentration of polyethyleneimine in the aqueous solution is 0.1% to 1%, and the mass concentration of piperazine is 0.1% to 1%. In some embodiments of the invention, the mass concentration of polyethyleneimine in the aqueous solution is 0.1% to 0.3%, and/or the mass concentration of piperazine is 0.1% to 0.3%. If the mass concentration of polyethyleneimine and piperazine is lower than 0.1%, the separation layer is incomplete, and the salt rejection rate is affected. If the mass concentration of polyethyleneimine/piperazine is higher than 1%, the separation layer is too thick, and the membrane flux is reduced.
In the step b, the basement membrane is immersed in the aqueous phase solution for 1-5 minutes, or the basement membrane is immersed in the aqueous phase solution for 2-3 minutes. The soaking time is too long, so that the base membrane excessively adsorbs water phase monomers, the separation layer is too thick, and the membrane flux is reduced.
The mass concentration of trimesoyl chloride in the solution of the co-mixed organic phase is 0.1-0.5%. In some embodiments of the invention, the mass concentration of trimesoyl chloride in the solution of the blended organic phase is 0.1% to 0.3%. If the mass concentration of trimesoyl chloride is less than 0.1%, the separation layer is incomplete, and the salt rejection rate is affected. If the mass concentration of trimesoyl chloride is higher than 0.5%, the degree of crosslinking of the separation layer is excessively high, and the membrane flux is reduced.
In one realizable manner, the amphiphilic block copolymer is selected from at least one of polyethylene-b-polymethyl acrylate, polyethylene-b-polymethyl methacrylate, polymethyl acrylate-b-polyethylene-b-polymethyl acrylate, and polymethyl methacrylate-b-polyethylene-b-polymethyl methacrylate. In the invention, the amphiphilic block copolymer exists in the form of nano particles, the particle size is 20-50nm, and the mass fraction in the solution of the co-mixed organic phase is 0.1-0.5%. In some embodiments, the amphiphilic block copolymer has a mass fraction in the solution of the blended organic phase of 0.1% to 0.3%. By adopting the amphiphilic block copolymer nano-particles, nano-particles can be formed to be attached to the surface of the nanofiltration membrane, the swelling size in water is increased, more 'water' channels are formed, and thus, more water yield is obtained; and because a large number of hydroxyl groups are contained in the hydrophilic chain segment, the hydrophilicity of the membrane is greatly increased, so that the pollution resistance of the nanofiltration membrane is improved. If the mass fraction of the amphiphilic block copolymer is less than 0.1%, the nano-reinforcing effect is not significant. If the mass fraction of the amphiphilic block copolymer is higher than 0.5%, the nano material can be agglomerated, and the integrity of the nanofiltration membrane can be affected. In one embodiment, the nanoparticles have a particle size of 10 to 100nm. In another embodiment, interfacial polymerization produces nanofiltration separation layers having a thickness of between 30-80nm and nanoparticles having a particle size of between 20-50nm, preventing the penetration of nanomaterials through the entire separation layer, affecting membrane integrity.
In a realizable mode, the basement membrane after the aqueous phase impregnation is immersed into the mixed organic phase solution in the step c for 1-5 minutes; or immersing the basement membrane after the water phase is immersed in the mixed organic phase solution for 2-3 minutes. Too long soaking time can cause the base membrane to excessively adsorb monomers, cause the separation layer to be too thick, and influence membrane flux.
The solvent in the solution of the mixed organic phase is at least one selected from the group consisting of amyl acetate, ethyl acetate and cyclohexane. The preparation method comprises the steps of preparing a mixed organic phase solution, dissolving trimesoyl chloride in a solvent, and dispersing an amphiphilic block copolymer in an organic phase by ultrasound.
In the step c, the drying temperature is 80-100 ℃. Drying above 100 ℃ can result in excessive dehydration of the membrane and excessive shrinkage of the membrane pores, affecting the water flux produced by the membrane. Typically, the drying time is 8-10 minutes.
The invention also provides a composite nanofiltration membrane prepared by the preparation method of the composite nanofiltration membrane.
The invention also provides an application of the composite nanofiltration membrane in sewage treatment.
According to the embodiment of the invention, through interfacial polymerization, the generated nanofiltration membrane contains amphiphilic block copolymer nano-scale spherical particles, and the phenomenon of swelling can occur in water, so that spherical particles with larger sizes are obtained, and thus a 'water' channel is formed, and larger water yield is obtained. The amphiphilic copolymer has a hydrophilic end (polypropylene homopolymer) and a hydrophobic end (polyethylene), a hydrophilic chain segment can be effectively enriched on the nanofiltration membrane, and the tail end of the block copolymer contains a large number of hydroxyl groups, so that the hydrophilicity of the membrane is greatly increased, and the pollution resistance of the membrane is enhanced; meanwhile, the problem that the membrane separation layer is easy to fall off can be obviously improved due to the chemical bond effect between the two blocks.
Detailed Description
The present invention is described in detail by the following specific examples, but the present invention is not limited to the following examples.
Comparative example 1:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into a water-phase solution of polyethyleneimine with the mass concentration of 0.2% and piperazine with the mass concentration of 0.2%, and keeping for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a trimesoyl chloride solution (oil phase) with the mass concentration of 0.1 percent, wherein the organic solution is cyclohexane and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for keeping for 8 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
At 25 +/-2 deg.C and 0.31MPa, 250ppm magnesium sulfate solution is used as test water sample for testThe separation performance of the membrane yarn is as follows: the membrane wire desalination rate is 90.2 percent, and the water flux is 33.1L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalinization rate is 82.3 percent, and the water flux is 24.3L/m 2 h, the flux reduction was 26.8%.
Comparative example 2:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into a piperazine water solution with the mass concentration of 0.5% for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a 0.1 mass percent solution of uniformly dispersed trimesoyl chloride (mass concentration of 0.1%) of block copolymer polyethylene-b-polymethyl acrylate, wherein the organic solution is cyclohexane, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for keeping for 8 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalinization rate is 63.2 percent, and the water flux is 67.2L/m 2 h. Because polyethyleneimine is not added and a nanofiltration membrane is not formed, the solution directly permeates, the salt rejection rate is very low, and the flux is high.
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken and is used as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then pure water is used for washing membrane filaments for 2 minutes; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 52.1 percent, and the water flux is 47.7L/m 2 h, the flux reduction was 29.0%.
Example 1:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.2% of polyethyleneimine and 0.1% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 8 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a 0.2 mass percent trimesoyl chloride (mass concentration of 0.2%) solution in which the block copolymer polyethylene-b-polymethyl acrylate with mass concentration of 0.1% is uniformly dispersed, wherein the organic solution is cyclohexane, and keeping for 1 minute; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blowing oven at 90 ℃ for 8 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.5 percent, and the water flux is 37.2L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken and is used as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then pure water is used for washing membrane filaments for 2 minutes; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalinization rate is 91.0%, and the water flux is 35.7L/m 2 h, the flux reduction rate was 4.0%.
Example 2:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.3% of polyethyleneimine and 0.3% of piperazine water solution by mass concentration for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a 0.3 mass percent solution of uniformly dispersed trimesoyl chloride (mass concentration is 0.3 percent) of block copolymer polyethylene-b-polymethyl acrylate, wherein the organic solution is ethyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for keeping for 9 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalinization rate is 94.3 percent, and the water flux is 36.4L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 92.1 percent, and the water flux is 35.1L/m 2 h, the flux reduction rate was 3.6%.
Example 3:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.2% of polyethyleneimine and 0.1% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 8 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a 0.2 mass percent solution of trimesoyl chloride (mass concentration is 0.2 percent) in which a block copolymer polyethylene-b-polymethyl acrylate is uniformly dispersed, wherein the organic solution is amyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blowing oven at 90 ℃ for 9 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane-silk desalination rate is 93.5%, and the water flux is 37.5L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 92.1 percent, and the water flux is 36.2L/m 2 h, the flux reduction rate was 3.5%.
Example 4:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.1% of polyethyleneimine and 0.2% of piperazine water solution by mass concentration for 3 minutes; taking the membrane filaments out of the water phase, vertically hanging for 9 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer polymethyl acrylate-b-polyethylene-b-polymethyl acrylate with mass concentration of 0.1%, wherein the organic solution is amyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blowing oven at 90 ℃ for 10 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.4 percent, and the water flux is 35.8L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken and is used as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then pure water is used for washing membrane filaments for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalinization rate is 91.3 percent, and the water flux is 33.6L/m 2 h, the flux reduction rate was 6.1%.
Example 5:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.2% of polyethyleneimine and 0.2% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 8 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer of polymethyl acrylate-b-polyethylene-b-polymethyl acrylate with mass concentration of 0.2%, wherein the organic solution is ethyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 9 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.6 percent, and the water flux is 36.5L/m 2 h。
In order to evaluate the anti-pollution capability of the composite nanofiltration membrane, nearby river water is taken and operated for 1 hour under the pressure of 0.31MPa by taking the river water as a water sample, and then the membrane filaments are washed by pure water for 2 minutesA clock; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalinization rate is 90.9 percent, and the water flux is 34.9L/m 2 h, the flux reduction rate was 4.4%.
Example 6:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.3% of polyethyleneimine and 0.3% of piperazine water solution for 3 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer of polymethyl acrylate-b-polyethylene-b-polymethyl acrylate with mass concentration of 0.3%, wherein the organic solution is cyclohexane, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 10 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.3 percent, and the water flux is 36.3L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalinization rate is 91.2 percent, and the water flux is 34.6L/m 2 h, the flux reduction rate was 4.7%.
Example 7:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.1% of polyethyleneimine and 0.2% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 8 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a 0.2 mass percent solution of uniformly dispersed trimesoyl chloride (mass concentration is 0.2 percent) of block copolymer polyethylene-b-polymethyl methacrylate, wherein the organic solution is amyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a 90 ℃ blast oven, keeping the temperature for 10 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 93.1%, and the water flux is 36.2L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken and is used as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then pure water is used for washing membrane filaments for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 92.4 percent, and the water flux is 34.3L/m 2 h, the flux reduction rate was 5.2%.
Example 8:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.2% of polyethyleneimine and 0.2% of piperazine water solution for 3 minutes; taking the membrane filaments out of the water phase, vertically hanging for 9 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a 0.3 mass percent solution of uniformly dispersed trimesoyl chloride (mass concentration of 0.1 percent) of block copolymer polyethylene-b-polymethyl methacrylate, wherein the organic solution is cyclohexane and keeping for 3 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 9 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.5 percent, and the water flux is 35.9L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 91.7 percent, and the water flux is 34.5L/m 2 h, fluxThe reduction rate was 3.9%.
Example 9:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.2% of polyethyleneimine and 0.1% of piperazine water solution by mass concentration for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments adsorbing the water phase into a 0.1 mass percent trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer polyethylene-b-polymethyl methacrylate which is uniformly dispersed, wherein the organic solution is ethyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 8 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.6 percent, and the water flux is 36.4L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 90.7 percent, and the water flux is 35.1L/m 2 h, the flux reduction rate was 3.6%.
Example 10:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.2% of polyethyleneimine and 0.3% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a segmented copolymer polymethyl methacrylate-b-polyethylene-b-polymethyl methacrylate with mass concentration of 0.3%, wherein the organic solution is amyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blowing oven at 90 ℃ for 10 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 94.1 percent, and the water flux is 37.8L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken and is used as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then pure water is used for washing membrane filaments for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 92.2 percent, and the water flux is 36.2L/m 2 h, the flux reduction rate was 4.2%.
Example 11:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.1% of polyethyleneimine and 0.1% of piperazine water solution for 3 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer of polymethyl methacrylate-b-polyethylene-b-polymethyl methacrylate with mass concentration of 0.2%, wherein the organic solution is pentane acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 10 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 93.4%, and the water flux is 37.2L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalinization rate is 91.4 percent, and the water flux is 35.9L/m 2 h, the flux reduction rate was 3.5%.
Example 12:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.2% of polyethyleneimine and 0.3% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then immersing the membrane filaments adsorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration is 0.2%) solution of a block copolymer polymethyl methacrylate-b-polyethylene-b-polymethyl methacrylate with mass concentration of 0.1%, wherein the organic solution is pentane acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 8 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.1 percent, and the water flux is 37.4L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 90.7 percent, and the water flux is 36.1L/m 2 h, the flux reduction rate was 3.5%.
Example 13:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.5% of polyethyleneimine and 0.7% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a 0.1 mass percent solution of the uniformly dispersed trimesoyl chloride (mass concentration is 0.3 percent) of the block copolymer polyethylene-b-polymethyl acrylate, wherein the organic solution is ethyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 9 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: membrane silk stripThe salt rate is 93.2 percent, and the water flux is 34.1L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane-filament desalination rate is 90.3%, and the water flux is 31.9L/m 2 h, the flux reduction rate was 6.4%.
Example 14:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.2% of polyethyleneimine and 0.9% of piperazine water solution by mass concentration for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then immersing the membrane filaments adsorbing the water phase into a 0.3 mass percent trimesoyl chloride (mass concentration is 0.3%) solution in which a block copolymer polyethylene-b-polymethyl acrylate is uniformly dispersed, wherein the organic solution is ethyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 9 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.8 percent, and the water flux is 35.2L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalinization rate is 90.4 percent, and the water flux is 32.8L/m 2 h, the flux reduction rate was 6.8%.
Example 15:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.8% of polyethyleneimine and 0.2% of piperazine water solution by mass concentration for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 8 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer polymethyl acrylate-b-polyethylene-b-polymethyl acrylate with mass concentration of 0.1%, wherein the organic solution is ethyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for keeping for 9 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 93.4%, and the water flux is 34.9L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 90.6 percent, and the water flux is 32.5L/m 2 h, the flux reduction rate was 6.9%.
Example 16:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.3% of polyethyleneimine and 0.6% of piperazine water solution by mass concentration for 3 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer of polymethyl acrylate-b-polyethylene-b-polymethyl acrylate with mass concentration of 0.2%, wherein the organic solution is cyclohexane, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 10 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.1 percent, and the water flux is 33.9L/m 2 h。
To evaluate the anti-pollution capability of the composite nanofiltration membrane, nearby river water is taken and the pressure is 0.31MPa, so as toRunning for 1h by taking river water as a water sample, and then washing the membrane filaments for 2 minutes by using pure water; and under the pressure of 0.31MPa, taking a 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 89.7 percent, and the water flux is 31.7L/m 2 h, the flux reduction rate was 6.5%.
Example 17:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.4% of polyethyleneimine and 0.9% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 8 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a 0.1 mass percent solution of uniformly dispersed trimesoyl chloride (mass concentration of 0.2 percent) of block copolymer polyethylene-b-polymethyl methacrylate, wherein the organic solution is amyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a 90 ℃ blast oven, keeping the temperature for 10 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalinization rate is 94.9 percent, and the water flux is 34.2L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the nearby river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalinization rate is 91.2 percent, and the water flux is 32.1L/m 2 h, the flux reduction rate was 6.1%.
Example 18:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.6% of polyethyleneimine and 0.2% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then immersing the membrane filaments adsorbing the water phase into a 0.3 mass percent trimesoyl chloride (mass concentration is 0.2%) solution of a block copolymer polyethylene-b-polymethyl methacrylate which is uniformly dispersed, wherein the organic solution is ethyl acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 8 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 92.5 percent, and the water flux is 35.1L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the nearby river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane yarn desalting rate is 90.1%, and the water flux is 33.1L/m 2 h, the flux reduction rate was 5.7%.
Example 19:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.1% of polyethyleneimine and 0.6% of piperazine water solution for 3 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer of polymethyl methacrylate-b-polyethylene-b-polymethyl methacrylate with mass concentration of 0.1%, wherein the organic solution is pentane acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 10 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 94.1 percent, and the water flux is 34.3L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample to retest the separation performance of the membrane yarnThe results obtained were as follows: the membrane wire desalination rate is 91.2 percent, and the water flux is 31.9L/m 2 h, the flux reduction rate was 7.0%.
Example 20:
soaking membrane filaments in pure water by using a polysulfone hollow fiber ultrafiltration membrane, and then putting the cleaned membrane filaments into 0.7% of polyethyleneimine and 0.2% of piperazine water solution for 2 minutes; taking the membrane filaments out of the water phase, vertically hanging for 10 minutes, and draining the membrane filaments; then soaking the membrane filaments absorbing the water phase into a uniformly dispersed trimesoyl chloride (mass concentration of 0.2%) solution of a block copolymer of polymethyl methacrylate-b-polyethylene-b-polymethyl methacrylate with mass concentration of 0.3%, wherein the organic solution is pentane acetate, and keeping for 2 minutes; and taking the membrane filaments out of the oil phase, putting the membrane filaments into a blast oven at the temperature of 80 ℃ for 8 minutes, and drying to obtain the polysulfone composite nanofiltration membrane.
The separation performance of the membrane filaments is tested by taking 250ppm magnesium sulfate solution as a test water sample at 25 +/-2 ℃ and under the pressure of 0.31MPa, and the obtained results are as follows: the membrane wire desalination rate is 93.1%, and the water flux is 35.5L/m 2 h。
In order to evaluate the anti-pollution capacity of the composite nanofiltration membrane, nearby river water is taken, the river water is taken as a water sample under the pressure of 0.31MPa, the operation is carried out for 1 hour, and then the membrane filaments are washed by pure water for 2 minutes; and under the pressure of 0.31MPa, taking 250ppm magnesium sulfate solution as a test water sample, and retesting the separation performance of the membrane yarns, wherein the obtained results are as follows: the membrane wire desalination rate is 90.2 percent, and the water flux is 33.2L/m 2 h, the flux reduction was 6.5%.
Claims (14)
1. A preparation method of a composite nanofiltration membrane comprises the following steps:
a. providing a base film;
b. providing an aqueous solution containing polyethyleneimine and piperazine, immersing a base membrane into the aqueous solution, taking out, and draining to obtain the base membrane subjected to aqueous impregnation;
c. providing a blended organic phase solution containing trimesoyl chloride and an amphiphilic block copolymer, immersing a base membrane after water phase immersion into the blended organic phase solution, and taking out and drying to obtain a composite nanofiltration membrane;
the amphiphilic block copolymer is selected from at least one of polyethylene-b-polymethyl acrylate, polyethylene-b-polymethyl methacrylate, polymethyl acrylate-b-polyethylene-b-polymethyl acrylate, and polymethyl methacrylate-b-polyethylene-b-polymethyl methacrylate.
2. The preparation method of the composite nanofiltration membrane according to claim 1, wherein the base membrane is one selected from a polysulfone membrane, a polyethersulfone membrane, a polyvinylidene fluoride membrane, a polyacrylonitrile membrane and a polytetrafluoroethylene membrane.
3. The preparation method of the composite nanofiltration membrane according to claim 1, wherein the mass concentration of polyethyleneimine in the aqueous solution is 0.1-1%, and the mass concentration of piperazine is 0.1-1%.
4. The preparation method of the composite nanofiltration membrane according to claim 3, wherein the mass concentration of polyethyleneimine in the aqueous phase solution is 0.1-0.3%, and/or the mass concentration of piperazine is 0.1-0.3%.
5. The method for preparing the composite nanofiltration membrane according to claim 1, wherein the basement membrane is immersed in the aqueous solution in the step b for 1-5 minutes.
6. The method for preparing a composite nanofiltration membrane according to claim 1, wherein the mass concentration of trimesoyl chloride in the mixed organic phase solution is 0.1-0.5%.
7. The method for preparing a composite nanofiltration membrane according to claim 6, wherein the mass concentration of trimesoyl chloride in the mixed organic phase solution is 0.1-0.3%.
8. The method for preparing a composite nanofiltration membrane according to claim 1, wherein the amphiphilic block copolymer in the solution of the co-mixed organic phase exists in the form of nanoparticles, the particle size is 10-100nm, and the mass fraction in the solution of the co-mixed organic phase is 0.1-0.5%.
9. The method for preparing a composite nanofiltration membrane according to claim 8, wherein the mass fraction of the amphiphilic block copolymer in the co-mixed organic phase solution is 0.1-0.3%.
10. The method for preparing the composite nanofiltration membrane according to claim 1, wherein the aqueous-phase-impregnated basement membrane is immersed in the organic-phase-mixed solution for 1 to 5 minutes in step c.
11. The method for preparing the composite nanofiltration membrane according to claim 1, wherein the solvent in the mixed organic phase solution is at least one selected from amyl acetate, ethyl acetate and cyclohexane.
12. The method for preparing a composite nanofiltration membrane according to claim 1, wherein the drying temperature is 80-100 ℃.
13. A composite nanofiltration membrane prepared according to the preparation method of the composite nanofiltration membrane of claim 1.
14. Use of a composite nanofiltration membrane according to claim 13 in wastewater treatment.
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