CN112473397B - High-strength flat filter membrane and preparation method thereof - Google Patents
High-strength flat filter membrane and preparation method thereof Download PDFInfo
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- CN112473397B CN112473397B CN202011513250.7A CN202011513250A CN112473397B CN 112473397 B CN112473397 B CN 112473397B CN 202011513250 A CN202011513250 A CN 202011513250A CN 112473397 B CN112473397 B CN 112473397B
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- 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
- B01D69/06—Flat membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0009—Organic membrane manufacture by phase separation, sol-gel transition, evaporation or solvent quenching
- B01D67/0013—Casting processes
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- 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
- B01D71/26—Polyalkenes
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- 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
- B01D71/30—Polyalkenyl halides
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- 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
- B01D71/30—Polyalkenyl halides
- B01D71/32—Polyalkenyl halides containing fluorine atoms
- B01D71/34—Polyvinylidene fluoride
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- 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
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- 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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Dispersion Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses a high-strength flat filter membrane which consists of a support body and a filter membrane layer, wherein the support body is formed by parallelly arranging fiber woven pipes and adding reinforcing ribs on the surface of the support body, and the filter membrane layer is obtained by uniformly scraping and coating casting membrane liquid on the surface of the support body, solidifying, washing and drying. The support material of the invention endows the flat membrane with high breaking tensile strength in the radial direction and the latitudinal direction; and the hollow structure of the braided tube can be used as a water production flow channel of the flat membrane, and the permeation flux of the flat membrane is increased. The support material and the flat membrane are easy to prepare, can realize industrial production, can save the high cost of the ABS support plate, and reduce the use cost of the flat membrane.
Description
Technical Field
The invention relates to the field of water treatment separation membranes, in particular to a flat filter membrane and a preparation method thereof.
Background
As a high-efficiency low-pollution purification technology integrating separation and concentration, the flat membrane separation technology has the characteristics of good pollution resistance, good mechanical stability, no filament breakage, more convenient and faster cleaning method, longer cleaning period, long service life, low operating cost and the like, and is gradually and widely recognized, recognized and applied to sewage treatment in related industries. But its low packing density and high manufacturing cost limit its wide application.
The flat membrane is required to be manufactured into a flat membrane element, and the traditional flat membrane element consists of a flat membrane, a flow guide cloth and a flow guide plate. The guide plate plays a role in supporting and guiding flow in the element, and the common guide plate is 3-5 mm thick and high in cost. If the guide plate is removed from the flat membrane element, the problems of low packing density and high cost can be solved. Therefore, how to replace the guide plate becomes a research hotspot in the technical field of the flat membrane.
CN111804147A discloses an anti-pollution flat membrane, which has a plurality of recesses, wherein the recesses include a strip-shaped groove structure, a dotted recess structure, and a polygonal recess structure, and an included angle between the extending direction of the recess of the strip-shaped groove structure and the water flow direction on the surface of the membrane body is 0 ° to 180 °; the area of the water flowing to the concave part along the surface of the membrane body is guided by the concave part to form a vortex. CN105800773A discloses a self-supporting immersed flat membrane component, which adopts a self-supporting membrane component composed of a first membrane layer, a first non-woven fabric layer, a runner net, a second non-woven fabric layer and a second membrane layer, thereby omitting an ABS support plate of the traditional flat membrane component and greatly reducing the cost of the membrane component. CN108067104A discloses a preparation method of a self-supporting flat membrane element, which comprises the following steps: 1) Preparation of the support: warping monofilament and multifilament raw materials, weaving the raw materials into blank belts by a ribbon loom, sizing and shaping the blank belts, and cutting the monofilament by a hook cutting machine to form a belt-shaped support body with a single-sided hook structure; 2) Film coating: preparing a casting solution, coating the casting solution on the plane of the support body by using a scraper, and solidifying to form a film; 3) Preparing a connector: the method comprises the following steps of warping filaments, weaving into cloth through a warp knitting machine, performing double-sided fluffing treatment, and respectively using a warping machine, a high-speed warp knitting machine and a fluffing machine; 4) Compounding: the barbed surfaces of the two membranes are respectively attached to the hair surface of the connector, and a plurality of hair surface fibers are entangled by barbed hooks, so that the composite is achieved.
In view of the above, the thickness and the cost of use have been reduced by designing the structure of the flat membrane element, and no study has been made on the flat membrane itself.
Disclosure of Invention
The invention aims to overcome the defects of low filling density, high cost and the like caused by the fact that the current flat membrane needs to be guided and supported by an ABS (acrylonitrile butadiene styrene) supporting plate when in use, and provides a high-strength flat membrane which is high in strength, large in flux and provided with a guide channel.
The invention relates to a high-strength flat filter membrane, which consists of a support body and a filter membrane layer, wherein the support body is formed by parallelly arranging fiber braided tubes and adding reinforcing ribs on the surface of the fiber braided tubes, and the filter membrane layer is obtained by uniformly scraping and coating a casting membrane liquid on the surface of the support body, solidifying, washing and drying.
The invention also aims to provide a preparation method of the high-strength flat filter membrane, which is simple, short in process flow and capable of realizing large-scale industrial production.
A preparation method of a high-strength flat filter membrane comprises the following steps:
1) Preparation of the support: arranging the fiber braided tubes in parallel one by one to prepare a flat braided tube, and adding reinforcing ribs on the surface of one side vertical to the flat braided tube to prepare a support body;
2) Preparing a casting solution: mixing high molecular polymer powder, pore-forming agent, additive and solvent, dissolving, filtering and defoaming at 40-80 ℃ under stirring to obtain high molecular polymer membrane casting solution;
3) And (3) uniformly blade-coating the casting solution prepared in the step 2) on the surface of the support body connected with the reinforcing ribs, immediately placing the support body in the coagulating bath solution for coagulation, washing and drying to prepare the high-strength flat filter membrane.
According to the invention, the fiber braided tube in the step 1) is braided by a high-speed braiding machine from fiber bundles.
According to the invention, the diameter of the braided tube in step 1) is 1-3 mm.
According to the invention, the fiber of the braided tube in the step 1) is one or a mixture of polyester fiber, nylon fiber, polyethylene fiber, polypropylene fiber or glass fiber.
According to the invention, the fiber fineness of the braided tube in the step 1) is 100-3000 dtex.
According to the invention, the reinforcing ribs in the step 1) are one of polyester stranded yarns, nylon stranded yarns, polyethylene stranded yarns or polypropylene stranded yarns.
According to the invention, the diameter of the strengthening rib in the step 1) is 0.5-3 mm.
According to the invention, the distance between the reinforcing ribs in the step 1) is 5-50 mm.
According to the invention, the polymer in the step 2) is one or a mixture of polyvinylidene fluoride, polyacrylonitrile, polyvinyl chloride, polysulfone, polyethersulfone or cellulose acetate.
According to the invention, the pore forming agent in the step 2) is polyvinylpyrrolidone or polyethylene glycol.
According to the invention, the additive in the step 2) is one of water, glycerol, lithium chloride, isopropanol, triethylene glycol, polyvinyl alcohol or polyvinyl butyral.
According to the invention, the solvent in the step 2) is one of N, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide or N-methylpyrrolidone.
According to the invention, the mass ratio of the high molecular polymer powder, the pore-forming agent, the additive and the solvent in the step 2) is (10-30).
According to the invention, the coagulation bath liquid in the step 3) is water or a solvent water solution; the mass fraction of the solvent in the solvent water solution is 1-50%.
According to the invention, the temperature of the coagulation bath liquid in the step 3) is 10-60 ℃.
Compared with the prior art, the invention has the following advantages:
1. the structure that the fiber braided tubes are arranged in parallel and the vertical surfaces of the fiber braided tubes are connected with fiber reinforcing ribs is used as a supporting material of the flat membrane, so that the flat membrane is endowed with high breaking tensile strength in the radial direction and the weft direction; the hollow structure of the braided tube becomes a water production flow channel of the flat membrane, and the permeation flux of the flat membrane can be increased.
2. According to the invention, the pore-forming agent and the additive are added into the membrane casting solution, and the organic coordination and synergistic effect of the components enable the high-molecular polymer membrane casting solution to have proper dispersibility and stability, so that the interfacial wettability of the membrane casting solution and a coagulating bath can be effectively controlled, the coagulator and a solvent in the membrane casting solution are easy to diffuse and permeate at the interface, and the flat membranes with different apertures and different retention performances can be prepared by utilizing the effective combination of the formula of the membrane casting solution and the pore-forming conditions.
3. The support material and the flat membrane are easy to prepare, can realize industrial production, can save the high cost of the ABS support plate, and reduce the use cost of the flat membrane.
The specific implementation mode is as follows:
the present invention will be further described with reference to the following examples.
Example 1
(1) Arranging polyester fiber (100 dtex) braided tubes (with the diameter of 1 mm) in parallel one by one to form a flat braided tube, and adding polyester strand (with the diameter of 0.5 mm) reinforcing ribs on the surface of one side perpendicular to the flat braided tube at intervals of 5mm to form a support body;
(2) Weighing 10g of polyvinyl chloride, 1g of polyvinylpyrrolidone (K30), 1g of water and 88g of N, N-dimethylacetamide, and dissolving, filtering and defoaming at 80 ℃ under stirring to prepare a polyvinyl chloride membrane casting solution;
(3) Winding 2 layers of transparent adhesive tapes on two ends of a glass rod, coating the polyvinyl chloride casting solution on the surface of the support body with the reinforcing ribs prepared in the step 1) by using the glass rod at 80 ℃, immediately placing the support body in water at 60 ℃ for solidification, washing and drying to prepare the high-strength flat filter membrane, wherein the pure water flux of the flat filter membrane is 320L/m 2 ·h。
Example 2
(1) Arranging polyamide fiber (300 dtex) braided tubes (with the diameter of 3 mm) in parallel one by one to form a flat braided tube, and adding polyamide strand (with the diameter of 3 mm) reinforcing ribs on the surface of one side perpendicular to the flat braided tube every 50mm to form a support body;
(2) Weighing 15g of polyvinylidene fluoride, 2g of polyethylene glycol (molecular weight is 1000), 3g of polyvinyl butyral and 80g of N, N-dimethylformamide, stirring at 80 ℃, dissolving, filtering and defoaming to obtain a polyvinylidene fluoride casting solution;
(3) Winding 2 layers of transparent adhesive tapes on both ends of a glass rod, knife-coating polyvinylidene fluoride casting solution on the surface of the support having reinforcing ribs obtained in step 1) at 60 ℃ with the glass rod, immediately solidifying in an aqueous solution of 1% by mass N, N-dimethylformamide at 50 ℃, washing with water, and drying to obtain a high-strength flat filter membrane having a pure water flux of 273L/m 2 ·h。
Example 3
(1) Arranging polyethylene fiber (1000 dtex) braided tubes (with the diameter of 2 mm) in parallel one by one to form a flat braided tube, and adding polyester strand (with the diameter of 1 mm) reinforcing ribs at intervals of 40mm on the surface of one side perpendicular to the flat braided tube to form a support body;
(2) Weighing 30g of polysulfone, 8g of polyvinylpyrrolidone (K17), 8g of glycerol and 54g of N-methylpyrrolidone, and dissolving, filtering and defoaming the mixture at the temperature of 80 ℃ under stirring to prepare a polysulfone membrane casting solution;
(3) Winding 2 layers of transparent adhesive tapes on two ends of a glass rod, scraping and coating the polysulfone membrane casting solution on the surface of the support body with the reinforcing ribs prepared in the step 1) by using the glass rod at 70 ℃, immediately placing the support body in an N-methyl pyrrolidone aqueous solution with the concentration of 50 percent at 20 ℃, solidifying, washing and drying to prepare the high-strength flat filter membrane, wherein the pure water flux of the flat filter membrane is 156L/m 2 ·h。
Example 4
(1) Arranging polypropylene fiber (2000 dtex) braided tubes (with the diameter of 1 mm) in parallel one by one to prepare flat braided tubes, and adding reinforcing ribs of nylon strand wires (with the diameter of 2 mm) on the surface of one side perpendicular to the flat braided tubes at intervals of 30mm to prepare a support body;
(2) Weighing 20g of cellulose acetate, 5g of polyethylene glycol (molecular weight is 600), 5g of triethylene glycol and 70g of N, N-dimethylacetamide, and dissolving, filtering and defoaming the mixture at 80 ℃ under stirring to prepare a cellulose acetate membrane casting solution;
(3) Winding 2 layers of transparent adhesive tapes on both ends of a glass rod, using the glass rod to scrape and coat the cellulose acetate casting solution on the surface of the support body with the reinforcing ribs prepared in the step 1) at 50 ℃, immediately placing the support body in 30 percent of N, N-dimethylacetamide at 40 ℃, solidifying, washing and drying to prepare the high-strength flat filter membrane, wherein the pure water flux of the flat filter membrane is 225L/m 2 ·h。
Claims (16)
1. The preparation method of the high-strength flat filter membrane is characterized by comprising the following steps of:
1) Preparation of the support: arranging the fiber braided tubes in parallel one by one to prepare a flat braided tube, and adding reinforcing ribs on the surface of one side vertical to the flat braided tube to prepare a support body;
the reinforcing rib is one of polyester plied yarns, nylon plied yarns, polyethylene plied yarns or polypropylene plied yarns;
2) Preparing a casting solution: mixing high molecular polymer powder, pore-forming agent, additive and solvent, dissolving, filtering and defoaming at 40-80 ℃ under stirring to obtain high molecular polymer membrane casting solution;
3) And 3) uniformly blade-coating the casting solution prepared in the step 2) on the surface of the support body connected with the reinforcing ribs, immediately placing the support body in coagulating bath solution for coagulating, washing and drying to prepare the high-strength flat filter membrane.
2. The method as claimed in claim 1, wherein the fiber braided tube in step 1) is braided from fiber bundles by a high speed braiding machine.
3. The method as claimed in claim 1, wherein the diameter of the fiber braided tube in the step 1) is 1 to 3mm.
4. The method of claim 1, wherein the fibers of the woven tube in step 1) are one or a mixture of polyester fibers, polyamide fibers, polyethylene fibers, polypropylene fibers, or glass fibers.
5. The method according to claim 4, wherein the fiber titer is 100 to 3000dtex.
6. The method as set forth in claim 1, wherein the diameter of the reinforcing rib in the step 1) is 0.5 to 3mm.
7. The method as claimed in claim 1, wherein the interval between the reinforcing bars in the step 1) is 5 to 50mm.
8. The method according to claim 1, wherein the polymer in step 2) is one or a mixture of polyvinylidene fluoride, polyacrylonitrile, polyvinyl chloride, polysulfone, polyethersulfone or cellulose acetate.
9. The method as claimed in claim 1, wherein the pore forming agent in step 2) is polyvinylpyrrolidone or polyethylene glycol.
10. The method as claimed in claim 1, wherein the additive in step 2) is one of water, glycerin, lithium chloride, isopropyl alcohol, triethylene glycol, polyvinyl alcohol, and polyvinyl butyral.
11. The method according to claim 1, wherein the solvent in step 2) is one of N, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide or N-methylpyrrolidone.
12. The method of claim 1, wherein the mass ratio of the polymer powder, the pore-forming agent, the additive and the solvent in the step 2) is 10-30.
13. The method as claimed in claim 1, wherein the coagulation bath in step 3) is water or an aqueous solvent solution.
14. The method according to claim 13, wherein the mass fraction of the solvent in the aqueous solvent solution is 1 to 50%.
15. The method as set forth in claim 1, wherein the temperature of the coagulation bath in the step 3) is 10 to 60 ℃.
16. A high strength flat filter membrane prepared by the method of any one of claims 1 to 15.
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| CN202011513250.7A CN112473397B (en) | 2020-12-21 | 2020-12-21 | High-strength flat filter membrane and preparation method thereof |
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| CN112473397B true CN112473397B (en) | 2022-11-11 |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10138319A1 (en) * | 2001-08-10 | 2003-04-24 | Geesthacht Gkss Forschung | Membrane body and method for producing the same |
| CN203556297U (en) * | 2013-09-05 | 2014-04-23 | 厦门绿邦膜技术有限公司 | Hollow fiber pipe type flat membrane |
| CN104088059A (en) * | 2014-07-16 | 2014-10-08 | 杭州费尔过滤技术有限公司 | Membrane of hollow fiber membrane braided fabric |
| CN106334452A (en) * | 2016-08-26 | 2017-01-18 | 杭州太仆汽车科技有限公司 | Filter membrane component and preparation method thereof |
| CN107855007A (en) * | 2017-07-13 | 2018-03-30 | 枫科(北京)膜技术有限公司 | A kind of asymmetric forward osmosis membrane and preparation method thereof |
| WO2020172753A1 (en) * | 2019-02-28 | 2020-09-03 | Thetis Environmental Inc. | Flat sheet membrane with integral posts |
-
2020
- 2020-12-21 CN CN202011513250.7A patent/CN112473397B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10138319A1 (en) * | 2001-08-10 | 2003-04-24 | Geesthacht Gkss Forschung | Membrane body and method for producing the same |
| CN203556297U (en) * | 2013-09-05 | 2014-04-23 | 厦门绿邦膜技术有限公司 | Hollow fiber pipe type flat membrane |
| CN104088059A (en) * | 2014-07-16 | 2014-10-08 | 杭州费尔过滤技术有限公司 | Membrane of hollow fiber membrane braided fabric |
| CN106334452A (en) * | 2016-08-26 | 2017-01-18 | 杭州太仆汽车科技有限公司 | Filter membrane component and preparation method thereof |
| CN107855007A (en) * | 2017-07-13 | 2018-03-30 | 枫科(北京)膜技术有限公司 | A kind of asymmetric forward osmosis membrane and preparation method thereof |
| WO2020172753A1 (en) * | 2019-02-28 | 2020-09-03 | Thetis Environmental Inc. | Flat sheet membrane with integral posts |
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