CN117018895A - Preparation method of enhanced hollow fiber loose nanofiltration membrane - Google Patents
Preparation method of enhanced hollow fiber loose nanofiltration membrane Download PDFInfo
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- 239000012528 membrane Substances 0.000 title claims abstract description 61
- 239000012510 hollow fiber Substances 0.000 title claims abstract description 47
- 238000001728 nano-filtration Methods 0.000 title claims abstract description 33
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- 238000009987 spinning Methods 0.000 claims abstract description 46
- 239000000243 solution Substances 0.000 claims abstract description 38
- 239000000835 fiber Substances 0.000 claims abstract description 32
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims abstract description 27
- 238000003756 stirring Methods 0.000 claims abstract description 11
- 238000004804 winding Methods 0.000 claims abstract description 11
- 239000007864 aqueous solution Substances 0.000 claims abstract description 8
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 8
- 238000013329 compounding Methods 0.000 claims abstract description 7
- 238000002791 soaking Methods 0.000 claims abstract description 7
- 238000005406 washing Methods 0.000 claims abstract description 7
- 239000000654 additive Substances 0.000 claims abstract description 6
- 230000000996 additive effect Effects 0.000 claims abstract description 6
- 239000004094 surface-active agent Substances 0.000 claims abstract description 6
- 230000001112 coagulating effect Effects 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims abstract description 5
- 229920000642 polymer Polymers 0.000 claims abstract description 5
- 239000002904 solvent Substances 0.000 claims abstract description 5
- 238000009832 plasma treatment Methods 0.000 claims abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 17
- 229920002492 poly(sulfone) Polymers 0.000 claims description 14
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 claims description 12
- 239000007921 spray Substances 0.000 claims description 10
- 239000004952 Polyamide Substances 0.000 claims description 8
- 229920002647 polyamide Polymers 0.000 claims description 8
- 235000010482 polyoxyethylene sorbitan monooleate Nutrition 0.000 claims description 8
- 229920000053 polysorbate 80 Polymers 0.000 claims description 8
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical group CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 6
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 4
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 4
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 4
- 239000004695 Polyether sulfone Substances 0.000 claims description 3
- 238000009954 braiding Methods 0.000 claims description 3
- 229920000728 polyester Polymers 0.000 claims description 3
- 229920006393 polyether sulfone Polymers 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 2
- 239000002202 Polyethylene glycol Substances 0.000 claims description 2
- 239000012298 atmosphere Substances 0.000 claims description 2
- 238000000465 moulding Methods 0.000 claims description 2
- 229920001223 polyethylene glycol Polymers 0.000 claims description 2
- 229920000136 polysorbate Polymers 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 9
- 238000010438 heat treatment Methods 0.000 claims 1
- 238000000926 separation method Methods 0.000 abstract description 12
- 230000004907 flux Effects 0.000 abstract description 7
- 150000003839 salts Chemical class 0.000 abstract description 5
- 230000014759 maintenance of location Effects 0.000 abstract description 2
- 230000007774 longterm Effects 0.000 abstract 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 8
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 description 7
- 229920003081 Povidone K 30 Polymers 0.000 description 7
- 230000009172 bursting Effects 0.000 description 5
- IQFVPQOLBLOTPF-HKXUKFGYSA-L congo red Chemical compound [Na+].[Na+].C1=CC=CC2=C(N)C(/N=N/C3=CC=C(C=C3)C3=CC=C(C=C3)/N=N/C3=C(C4=CC=CC=C4C(=C3)S([O-])(=O)=O)N)=CC(S([O-])(=O)=O)=C21 IQFVPQOLBLOTPF-HKXUKFGYSA-L 0.000 description 5
- 238000000034 method Methods 0.000 description 5
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- 230000005540 biological transmission Effects 0.000 description 3
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- 238000002834 transmittance Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
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- 238000005516 engineering process Methods 0.000 description 2
- 229910017053 inorganic salt Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000012695 Interfacial polymerization Methods 0.000 description 1
- 229920004933 Terylene® Polymers 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
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- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 231100000086 high toxicity Toxicity 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000000614 phase inversion technique Methods 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- -1 salt ion Chemical class 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000001338 self-assembly Methods 0.000 description 1
- 150000003384 small molecules Chemical class 0.000 description 1
- 238000002145 thermally induced phase separation Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
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Classifications
-
- 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
-
- 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
- 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
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/08—Hollow fibre membranes
-
- 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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Nanotechnology (AREA)
- Water Supply & Treatment (AREA)
- Manufacturing & Machinery (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses a preparation method of an enhanced hollow fiber loose nanofiltration membrane, which comprises the following steps: s1, stirring and dissolving a film-forming polymer, a pore-forming agent, an additive, a surfactant and a solvent, and placing the mixture in a spinning kettle for vacuum defoamation to prepare a uniform spinning solution; s2, compounding the fiber braided tube with a spinning solution in a spinneret after online plasma treatment, solidifying and forming through a coagulating bath, and winding to obtain a nascent hollow fiber membrane; and S3, fully washing the nascent hollow fiber membrane to remove the pore-forming agent, then putting the nascent hollow fiber membrane into a glycerol aqueous solution for soaking, and airing to obtain the reinforced hollow fiber loose nanofiltration membrane. The preparation method effectively enhances the flux, the retention rate, the strength and the long-term operation stability of the hollow fiber loose nanofiltration membrane, and realizes the accurate and efficient separation of dye/salt.
Description
Technical Field
The invention relates to the technical field of membrane separation, in particular to a preparation method of an enhanced hollow fiber loose nanofiltration membrane.
Background
The printing and dyeing wastewater has the characteristics of high chromaticity, high salt content, high Chemical Oxygen Demand (COD), high toxicity (biological degradation resistance) and the like, and is recognized as complex, toxic and difficult-to-treat industrial organic wastewater. The membrane separation technology and the traditional technology are coupled and separated step by step, so that the high-efficiency treatment of the printing and dyeing wastewater can be realized, wherein the deep treatment of dye desalination (accurate separation of dye and salt) is the key for realizing the recycling utilization of the printing and dyeing wastewater.
The pore diameter of the loose nanofiltration membrane is generally between 2 and 5nm and is between the traditional nanofiltration and ultrafiltration, the separation mechanism comprises a size screening mechanism and a charge effect, the loose nanofiltration membrane has higher retention rate on small-molecule dye and higher transmittance on inorganic salt, can efficiently separate dye and inorganic salt in printing and dyeing wastewater, and has great application potential in the field of dye desalination advanced treatment. The preparation method of the loose nanofiltration membrane reported at present is mainly a two-step method, and one method is to prepare a base membrane by a phase inversion method or a thermally induced phase separation method and the like; the other is to modify the base film, including interfacial polymerization, grafting, deposition, layer-by-layer self-assembly, etc., and the two-step preparation process is relatively complex and the continuous preparation is difficult.
Compared with a flat plate or a rolled membrane, the hollow fiber membrane has the advantages of high filling density per unit volume, no need of a supporting body when the membrane assembly is integrated, large filtering area, small occupied area, relatively low cost and the like, and the hollow fiber membrane assembly for a laboratory has small difference in fluid flow form, separation effect and the like from an industrial scale membrane assembly, has better reproducibility and is easy for large-scale production. The general homogeneous hollow fiber loose nanofiltration membrane is easy to be flattened and compacted under higher operation pressure, the pore structure is easy to be destroyed, the permeation flux is attenuated, and the bending resistance and the stretching resistance are poor. The Chinese patent publication No. CN 110201546A discloses a dye desalination pressure-resistant hollow fiber loose nanofiltration membrane and a preparation method thereof, wherein the hollow fiber membrane comprises a polyether sulfone skin layer, a finger hole supporting layer and a fiber yarn reinforcement body from outside to inside, the mechanical property of the membrane is obviously improved, but the bonding strength of a separation layer and the reinforcement body is small, and the membrane is a key problem to be solved.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a preparation method of an enhanced hollow fiber loose nanofiltration membrane, which is simple to operate and can be continuously implemented on a large scale, wherein the prepared hollow fiber loose nanofiltration membrane has high strength and good separation performance.
For this purpose, the invention adopts the following technical scheme:
the preparation method of the enhanced hollow fiber loose nanofiltration membrane comprises the following steps:
s1, stirring and dissolving a film-forming polymer, a pore-forming agent, an additive, a surfactant and a solvent, and then placing the mixture into a spinning kettle, and preparing a uniform spinning solution after vacuum defoamation; wherein, the mass fraction of each substance is as follows:
the film-forming polymer is polysulfone, polyether sulfone or sulfonated polysulfone;
the additive is one of GO, MXene, MOF.
S2, compounding the fiber braided tube with the spinning solution in a spinneret after online plasma treatment, solidifying and forming through a coagulating bath, and winding to obtain a primary hollow fiber membrane; wherein: the spinneret is embedded, and the woven tube guide tube is embedded into the spinneret molding hole by 1-5 mm. Preferably, the plasma is in the atmosphere, the power is 250-300W, the distance between the spray gun is 1-5 mm, the air pressure of the spray gun is 0.08-0.15 MPa, and the treatment speed is 5-10 m/min.
Before the fiber braided tube enters the spinneret to be compounded with the spinning solution, the braided tube is treated on line through an atmospheric plasma device, so that the surface pollutant of the braided tube can be cleaned, the surface energy of the braided tube can be reduced, and the bonding strength of the spinning solution and the braided tube can be improved.
And S3, fully washing the nascent hollow fiber membrane with water to remove the pore-forming agent, then soaking in an aqueous solution of glycerol, and airing to obtain the reinforced hollow fiber loose nanofiltration membrane.
Preferably, in the step S1, the temperature is raised to 60-80 ℃ for stirring and dissolving; the time for vacuum defoaming is 1-3 h.
Preferably, the solvent in step S1 is dimethylformamide, dimethylacetamide or N-methylpyrrolidone.
In the step S1, polyvinylpyrrolidone or polyethylene glycol is selected as the pore-forming agent, and the molecular weight is 1000-50000.
The surfactant is Tween series surfactant, preferably Tween 80.
In the step S2, the fibers of the fiber woven tube are selected from polyester fibers or polyamide fibers, and are in a crochet or woven form, the outer diameter of the fiber woven tube is 1.4-2 mm, the wall thickness is 0.2-0.5 mm, and the density is 20-40 meshes. Since the polyamide fiber has low surface energy and good hydrophilicity, it is preferable to use a polyamide fiber woven tube.
In the step S2, the coagulating bath is water, the temperature is 0-25 ℃, and the air bath height is 5-25 cm.
The reinforced hollow fiber loose nanofiltration membrane prepared by the method has the breaking strength of 140-170 MPa, the bursting strength of 0.3-0.5 MPa, the water contact angle of 60-80 degrees, the pore size of the separation layer of 2-5 nm and the permeation flux of 100-200 Lm -2 h -1 The congo red interception rate is more than 99%, the monovalent salt ion transmittance is more than 90%, and the accurate and efficient separation of dye/salt can be realized.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the preparation method, the low-surface-energy polyamide fiber is preferentially adopted to prepare the braided tube, the fiber braided tube reinforcement is treated on line through plasma, the fiber braided tube reinforcement is cleaned, the surface energy of the fiber braided tube reinforcement is further reduced, and meanwhile, the spinning solution is extruded into the braided tube by using the embedded spinneret, so that the continuous large-scale preparation of the high (combined) strength hollow fiber loose nanofiltration membrane is realized, and the requirement of the use process on the mechanical property of the membrane wire can be completely met;
2. according to the preparation method, core liquid is not needed in the cavity of the fiber braiding tube in the spinning process, the thickness of the external separation layer and the thickness of the spinning solution embedded into the braiding tube are controllable, the operation of the preparation process is simple and easy, and the stability is high;
3. the preparation method adopts the hydrophilic additive to improve the hydrophilicity of the membrane surface and regulate and control the membrane pore structure, improves the anti-pollution performance of the hollow fiber loose nanofiltration membrane, and improves the separation performance of the hollow fiber loose nanofiltration membrane.
Drawings
FIG. 1 is a schematic longitudinal cross-sectional view of an embedded spinneret assembly for use in the present invention;
FIG. 2 is a schematic flow chart of the preparation method of the invention.
Detailed Description
The technical scheme of the invention is further described in detail below with reference to the accompanying drawings and examples.
Abbreviations used in the following examples have the following meanings:
PSF: polysulfone; PVP: polyvinylpyrrolidone; GO: oxidized graphene; DMAc: dimethylacetamide.
The structure of the embedded spinneret device used in the present invention is shown in fig. 1. The spinning solution enters the feed liquid cavity from the feed liquid inlet 11, and the fiber woven tube is introduced from the woven tube channel 13 formed in the center of the woven tube guide tube 12. Unlike the prior art spinneret assembly, the outlet of the woven tube guide tube 12 of the present invention is not flush with the outlet of the spinneret forming hole 10, but is recessed (embedded) by 1 to 5mm, thereby allowing the spinning solution to be extruded into the fiber woven tube, and making the combination of the two more firm. The inner diameter of the braided tube channel 12 is adapted (identical) to the outer diameter of the fiber braided tube.
In the following examples and comparative examples, the dope thickness was 100. Mu.m. The aqueous glycerol solution in the examples has a concentration of 30% by weight
Example 1
Referring to fig. 2, the preparation method of the enhanced hollow fiber loose nanofiltration membrane comprises the following steps:
s1, weighing spinning solution raw materials according to 28 weight percent of PSF,10 weight percent of PVP-K30, 0.2 weight percent of GO, 1 weight percent of Tween80 and 60.8 weight percent of DMAc, and firstly adding the Tween80 into the DMAc and stirring for 1h; adding GO into the solution, and performing ultrasonic treatment for 30min to uniformly disperse GO; finally, PVP-K30 and PSF are added, stirred and dissolved at 70 ℃ and then placed in a spinning kettle, and vacuum defoamation is carried out for 3 hours, so that a uniform spinning solution is obtained;
s2, extruding the spinning solution in an embedded spinneret (the embedding distance is 3 mm) through a spinning machine, compounding the spinning solution with a polyamide fiber braided tube with the outer diameter of 1.4mm, and carrying out on-line treatment on the braided tube through an atmospheric plasma cleaning device before the fiber braided tube enters the embedded spinneret to be compounded with the spinning solution, wherein the plasma power is 300W, the distance of a spray gun is 3mm, the air pressure of the spray gun is 0.1MPa, and the treatment speed is 6m/min. Curing and forming in a water coagulation bath (path is 3 m) at 5 ℃ through an air bath of 10cm, and then winding at a winding speed of 6m/min to obtain a nascent hollow fiber membrane;
s3, sequentially washing the nascent hollow fiber membrane, soaking in a glycerol aqueous solution and airing to obtain the reinforced hollow fiber loose nanofiltration membrane.
Through detection, the rupture strength of the hollow fiber loose nanofiltration membrane is 160MPa, the bursting strength is 0.4MPa, the water contact angle is 78 degrees, and the pure water flux is 152Lm under 0.4MPa -2 h -1 The congo red rejection rate is 99.5%, and the NaCl transmission rate is 93.6%.
Example 2
The preparation method of the enhanced hollow fiber loose nanofiltration membrane comprises the following steps:
s1, weighing spinning solution raw materials according to 25wt% of PSF,10wt% of PVP-K30 and 0.5wt%GO,2.5wt%Tween80, 62wt%DMAc, firstly adding Tween80 into DMAc, stirring for 1h, then adding GO into the solution, performing ultrasonic treatment for 30min to uniformly disperse GO, finally adding PVP-K30 and PSF, stirring and dissolving at 65 ℃, and placing in a spinning kettle for vacuum defoaming for 2.5h to obtain uniform spinning solution.
S2, extruding the spinning solution in an embedded spinneret (embedding distance is 3 mm) through a spinning machine, compounding the spinning solution with a polyamide fiber braided tube with the outer diameter of 1.4mm, and carrying out on-line treatment on the braided tube through an atmospheric plasma device before the fiber braided tube enters the spinneret to be compounded with the spinning solution, wherein the plasma power is 300W, the distance of a spray gun is 3mm, the air pressure of the spray gun is 0.1MPa, and the treatment speed is 8m/min. Curing and forming in a 10cm air bath and a 10 ℃ water coagulation bath (the path is 3 m), and then winding at a winding speed of 8m/min to obtain a nascent hollow fiber membrane;
s3, sequentially washing the nascent hollow fiber membrane, soaking in a glycerol aqueous solution and airing to obtain the reinforced hollow fiber loose nanofiltration membrane.
Through detection, the rupture strength of the hollow fiber loose nanofiltration membrane is 152MPa, the bursting strength is 0.3MPa, the water contact angle is 72 DEG, and the pure water flux is 183Lm under 0.4MPa -2 h -1 The congo red rejection rate is 99.1%, and the NaCl transmission rate is 95.2%.
Example 3
The preparation method of the enhanced hollow fiber loose nanofiltration membrane comprises the following steps:
s1, weighing spinning solution raw materials according to the mass fraction composition of 32wt% of PSF,8wt% of PVP-K30 and 0.1wt%GO,0.5wt%Tween80, 59.4wt%DMAc, firstly adding Tween80 into DMAc, stirring for 1h, then adding GO into the solution, carrying out ultrasonic treatment for 30min to uniformly disperse GO, finally adding PVP-K30 and PSF, stirring and dissolving at 75 ℃, and placing in a spinning kettle for vacuum defoaming for 3h to obtain uniform spinning solution.
S2, extruding the spinning solution through a spinning machine, compounding the spinning solution with a nylon fiber braided tube with the thickness of 1.8mm in an embedded spinneret (embedding distance is 3 mm), and carrying out on-line treatment on the braided tube by an atmospheric plasma device before the fiber braided tube enters the spinneret to be compounded with the spinning solution, wherein the plasma power is 300W, the distance of a spray gun is 2mm, the air pressure of the spray gun is 0.1MPa, and the treatment speed is 6m/min. Curing and forming in a water coagulation bath (path is 3 m) at 5 ℃ through an air bath of 15cm, and winding at a winding speed of 6m/min to obtain a nascent hollow fiber membrane;
s3, sequentially washing the nascent hollow fiber membrane, soaking in a glycerol aqueous solution and airing to obtain the reinforced hollow fiber loose nanofiltration membrane.
Through detection, the rupture strength of the hollow fiber loose nanofiltration membrane is 163MPa, the bursting strength is 0.5MPa, the water contact angle is 75 degrees, and the pure water flux is 108Lm under 0.4MPa -2 h -1 The congo red rejection rate is 99.9%, and the NaCl transmission rate is 90.5%.
Comparative example 1
S1, weighing spinning solution raw materials according to the mass fraction composition of 18wt% of PSF,10wt% of PVP-K30,1wt% of GO and 71wt% of DMAc, firstly adding GO into the DMAc solution, carrying out ultrasonic treatment for 30min to uniformly disperse GO, finally adding PVP-K30 and PSF, stirring and dissolving at 70 ℃, and placing in a spinning kettle for vacuum defoaming for 3h to obtain uniform spinning solution.
S2, extruding the spinning solution through a spinning machine, compounding the spinning solution with a 1.8mm terylene (polyester) fiber braided tube at a spinning nozzle outlet (embedding distance is 0 mm), curing and forming the spinning solution in a 10cm air bath and a 10 ℃ water coagulation bath (path is 3 m), and winding the spinning solution at a winding speed of 10m/min to obtain a primary hollow fiber membrane;
s3, sequentially washing the nascent hollow fiber membrane, soaking in a glycerol aqueous solution and airing to obtain the reinforced hollow fiber loose nanofiltration membrane.
Through detection, the rupture strength of the hollow fiber loose nanofiltration membrane is 142MPa, the bursting strength is 0.2MPa, the water contact angle is 83 degrees, and the pure water flux is 320Lm under 0.4MPa -2 h -1 The congo red rejection rate is 95.2%, the NaCl transmittance is 96.1%, and the dye/salt is difficult to separate efficiently.
Claims (10)
1. The preparation method of the enhanced hollow fiber loose nanofiltration membrane is characterized by comprising the following steps of:
s1, stirring and dissolving a film-forming polymer, a pore-forming agent, an additive, a surfactant and a solvent, and then placing the mixture into a spinning kettle, and preparing a uniform spinning solution after vacuum defoamation; wherein, the mass fraction of each substance is as follows:
the film-forming polymer is polysulfone, polyether sulfone or sulfonated polysulfone;
the additive is one of GO, MXene, MOF;
s2, compounding the fiber braided tube with the spinning solution in a spinneret after online plasma treatment, solidifying and forming through a coagulating bath, and winding to obtain a primary hollow fiber membrane; wherein:
the spinneret is embedded, and the woven tube guide tube is embedded into the spinneret molding hole by 1-5 mm;
and S3, fully washing the nascent hollow fiber membrane with water to remove the pore-forming agent, then soaking in an aqueous solution of glycerol, and airing to obtain the reinforced hollow fiber loose nanofiltration membrane.
2. The method of manufacturing according to claim 1, characterized in that: in the step S2, the plasma is in the atmosphere, the power is 250-300W, the distance between the spray gun and the plasma is 1-5 mm, the air pressure of the spray gun is 0.08-0.15 MPa, and the treatment speed is 5-10 m/min.
3. The method of manufacturing according to claim 1, characterized in that: in the step S1, heating to 60-80 ℃ for stirring and dissolving; the time for vacuum defoaming is 1-3 h.
4. The method of manufacturing according to claim 1, characterized in that: in step S1, the solvent is dimethylformamide, dimethylacetamide or N-methylpyrrolidone.
5. The method of manufacturing according to claim 1, characterized in that: in the step S1, the pore-forming agent is polyvinylpyrrolidone or polyethylene glycol, and the molecular weight is 1000-50000.
6. The method of manufacturing according to claim 1, characterized in that: in step S1, the surfactant is tween, preferably tween 80.
7. The method of manufacturing according to claim 1, characterized in that: in the step S2, the fiber braided tube is a polyester fiber braided tube or a polyamide fiber braided tube and is made in a crochet or braiding mode, the outer diameter of the fiber braided tube is 1.4-2 mm, the wall thickness is 0.2-0.5 mm, and the density is 20-40 meshes.
8. The method of manufacturing according to claim 7, wherein: the fiber braided tube is a polyamide fiber braided tube.
9. The method of manufacturing according to claim 1, characterized in that: in the step S2, the coagulating bath is water, the temperature is 0-25 ℃, and the air bath height is 5-25 cm.
10. The method of manufacturing according to claim 1, characterized in that: in step S3, the concentration of the glycerol aqueous solution is 20-40wt%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2023106186588 | 2023-05-30 | ||
| CN202310618658 | 2023-05-30 |
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| CN117230539A (en) * | 2023-11-14 | 2023-12-15 | 江苏中鲈科技发展股份有限公司 | Mechanical sensitive material for resistance type pressure sensor and preparation method and application thereof |
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| CN117230539A (en) * | 2023-11-14 | 2023-12-15 | 江苏中鲈科技发展股份有限公司 | Mechanical sensitive material for resistance type pressure sensor and preparation method and application thereof |
| CN117230539B (en) * | 2023-11-14 | 2024-03-19 | 江苏中鲈科技发展股份有限公司 | Mechanical sensitive material for resistance type pressure sensor and preparation method and application thereof |
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