CN112426889A - Modified PVC hollow fiber ultrafiltration membrane and preparation method thereof - Google Patents
Modified PVC hollow fiber ultrafiltration membrane and preparation method thereof Download PDFInfo
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- CN112426889A CN112426889A CN202011279680.7A CN202011279680A CN112426889A CN 112426889 A CN112426889 A CN 112426889A CN 202011279680 A CN202011279680 A CN 202011279680A CN 112426889 A CN112426889 A CN 112426889A
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- 239000012528 membrane Substances 0.000 title claims abstract description 132
- 238000000108 ultra-filtration Methods 0.000 title claims abstract description 101
- 239000012510 hollow fiber Substances 0.000 title claims abstract description 45
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
- 239000012792 core layer Substances 0.000 claims abstract description 121
- 239000002344 surface layer Substances 0.000 claims abstract description 101
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 67
- 239000011148 porous material Substances 0.000 claims abstract description 25
- 239000002346 layers by function Substances 0.000 claims abstract description 24
- 238000001914 filtration Methods 0.000 claims abstract description 13
- 239000000243 solution Substances 0.000 claims description 151
- 238000005266 casting Methods 0.000 claims description 122
- 239000004800 polyvinyl chloride Substances 0.000 claims description 81
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 81
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 claims description 71
- 239000011259 mixed solution Substances 0.000 claims description 68
- 238000003756 stirring Methods 0.000 claims description 66
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 58
- 239000002033 PVDF binder Substances 0.000 claims description 57
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 57
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 45
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 42
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 42
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 38
- 239000002202 Polyethylene glycol Substances 0.000 claims description 38
- 229920001223 polyethylene glycol Polymers 0.000 claims description 38
- 238000002156 mixing Methods 0.000 claims description 35
- 238000004140 cleaning Methods 0.000 claims description 23
- 239000008367 deionised water Substances 0.000 claims description 23
- 229910021641 deionized water Inorganic materials 0.000 claims description 23
- 239000000835 fiber Substances 0.000 claims description 22
- 238000010438 heat treatment Methods 0.000 claims description 22
- 239000004695 Polyether sulfone Substances 0.000 claims description 21
- 229920006393 polyether sulfone Polymers 0.000 claims description 21
- 238000009987 spinning Methods 0.000 claims description 20
- KKEYFWRCBNTPAC-UHFFFAOYSA-L terephthalate(2-) Chemical compound [O-]C(=O)C1=CC=C(C([O-])=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-L 0.000 claims description 20
- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 claims description 19
- 235000013539 calcium stearate Nutrition 0.000 claims description 19
- 239000008116 calcium stearate Substances 0.000 claims description 19
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 19
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 19
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 19
- XOOUIPVCVHRTMJ-UHFFFAOYSA-L zinc stearate Chemical compound [Zn+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O XOOUIPVCVHRTMJ-UHFFFAOYSA-L 0.000 claims description 19
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 18
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 18
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 claims description 18
- DXPPIEDUBFUSEZ-UHFFFAOYSA-N 6-methylheptyl prop-2-enoate Chemical compound CC(C)CCCCCOC(=O)C=C DXPPIEDUBFUSEZ-UHFFFAOYSA-N 0.000 claims description 18
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 claims description 18
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 claims description 18
- VOZRXNHHFUQHIL-UHFFFAOYSA-N glycidyl methacrylate Chemical compound CC(=C)C(=O)OCC1CO1 VOZRXNHHFUQHIL-UHFFFAOYSA-N 0.000 claims description 18
- XECAHXYUAAWDEL-UHFFFAOYSA-N acrylonitrile butadiene styrene Chemical compound C=CC=C.C=CC#N.C=CC1=CC=CC=C1 XECAHXYUAAWDEL-UHFFFAOYSA-N 0.000 claims description 17
- 239000004676 acrylonitrile butadiene styrene Substances 0.000 claims description 17
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 claims description 17
- 239000011248 coating agent Substances 0.000 claims description 17
- 238000000576 coating method Methods 0.000 claims description 17
- 239000004925 Acrylic resin Substances 0.000 claims description 16
- XKMZOFXGLBYJLS-UHFFFAOYSA-L zinc;prop-2-enoate Chemical compound [Zn+2].[O-]C(=O)C=C.[O-]C(=O)C=C XKMZOFXGLBYJLS-UHFFFAOYSA-L 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 15
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 14
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 14
- 239000007795 chemical reaction product Substances 0.000 claims description 14
- 238000002791 soaking Methods 0.000 claims description 12
- 239000004342 Benzoyl peroxide Substances 0.000 claims description 9
- OMPJBNCRMGITSC-UHFFFAOYSA-N Benzoylperoxide Chemical compound C=1C=CC=CC=1C(=O)OOC(=O)C1=CC=CC=C1 OMPJBNCRMGITSC-UHFFFAOYSA-N 0.000 claims description 9
- 235000019400 benzoyl peroxide Nutrition 0.000 claims description 9
- 238000013329 compounding Methods 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 8
- 238000003851 corona treatment Methods 0.000 claims description 8
- 238000000151 deposition Methods 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 8
- 239000007822 coupling agent Substances 0.000 claims description 7
- ZQMHJBXHRFJKOT-UHFFFAOYSA-N methyl 2-[(1-methoxy-2-methyl-1-oxopropan-2-yl)diazenyl]-2-methylpropanoate Chemical compound COC(=O)C(C)(C)N=NC(C)(C)C(=O)OC ZQMHJBXHRFJKOT-UHFFFAOYSA-N 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 7
- FZHAPNGMFPVSLP-UHFFFAOYSA-N silanamine Chemical compound [SiH3]N FZHAPNGMFPVSLP-UHFFFAOYSA-N 0.000 claims description 7
- 238000009210 therapy by ultrasound Methods 0.000 claims description 7
- 229920002125 Sokalan® Polymers 0.000 claims description 4
- 239000004584 polyacrylic acid Substances 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 2
- 230000006872 improvement Effects 0.000 abstract description 7
- 230000002349 favourable effect Effects 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 16
- 239000010410 layer Substances 0.000 description 15
- 230000004907 flux Effects 0.000 description 6
- 230000014759 maintenance of location Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 4
- 230000001737 promoting effect Effects 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 239000002585 base Substances 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 230000008961 swelling Effects 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- -1 dimethyl azodiisobutyrate modified calcium carbonate Chemical class 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 230000002195 synergetic effect Effects 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
- B01D69/08—Hollow fibre 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
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/145—Ultrafiltration
-
- 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
- B01D67/0011—Casting solutions therefor
-
- 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
-
- 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
-
- 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
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Water Supply & Treatment (AREA)
- Dispersion Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Organic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses a modified PVC hollow fiber ultrafiltration membrane and a preparation method thereof, wherein the ultrafiltration membrane comprises an upper functional layer and a lower functional layer, the upper functional layer comprises an upper functional core layer and an upper functional surface layer, the lower functional layer comprises a lower functional core layer and a lower functional surface layer, the upper functional core layer is positioned below the upper functional surface layer, and the upper functional core layer is positioned above the lower functional surface layer. According to the invention, the ultrafiltration membrane is determined to be composed of the upper functional layer and the lower functional layer by setting the structure of the ultrafiltration membrane, the upper functional layer and the lower functional layer are both composed of the core layer and the surface layer, and the average pore diameters of pores in the upper functional core layer, the upper functional surface layer, the lower functional core layer and the lower functional surface layer are different, so that the pore structures of the functional surface layer and the functional core layer with gradually reduced pore diameters from top to bottom are formed, water flow permeation is promoted, the filtration area is further increased, the improvement of water treatment efficiency is facilitated, and the setting of the ultrafiltration membrane structure can provide a favorable basis for the improvement of the mechanical.
Description
Technical Field
The invention relates to the technical field of water treatment, in particular to a modified PVC hollow fiber ultrafiltration membrane and a preparation method thereof.
Background
The hollow fiber is a chemical fiber with a fiber axial direction having a thin tubular cavity, and is often applied to the field of water treatment, the ultrafiltration membrane is an artificial permeable membrane prepared from a high polymer material and used in the process of water treatment ultrafiltration, the pressure is used as a driving force for separating high polymer colloid or suspended particles from a solution, the ultrafiltration membrane prepared from the hollow fiber is one of the types of ultrafiltration membranes, the micropores are distributed on the wall of the hollow fiber, raw water flows in the outer side or the inner cavity of the hollow fiber under pressure, so that the ultrafiltration membrane intercepts substances in water, and the ultrafiltration membrane is small in thickness and is often applied after being combined with other functional membranes to form a component, and the mechanical property of a single membrane body is weak. Therefore, the modified PVC hollow fiber ultrafiltration membrane and the preparation method thereof are provided.
Disclosure of Invention
The invention aims to provide a modified PVC hollow fiber ultrafiltration membrane and a preparation method thereof, which aim to solve the problems in the background technology.
In order to solve the technical problems, the invention provides the following technical scheme: the utility model provides a modified PVC hollow fiber milipore filter and preparation method thereof, the milipore filter includes functional layer and lower functional layer, go up the functional layer and include function sandwich layer and last function top layer, lower functional layer includes function sandwich layer and lower function top layer down, go up the function sandwich layer and be located the below on function top layer, go up the function sandwich layer and be located the top on function top layer down, the function sandwich layer is located the below on function top layer down, go up function sandwich layer and lower function top layer and make by modified polyvinyl chloride.
Further, the upper functional core layer and the lower functional core layer are prepared from the following components in parts by weight: 10.5-13.5 parts of polyvinyl chloride, 1.5-4.5 parts of sulfonated polyether sulfone, 3-5 parts of polyvinylidene fluoride, 48-56 parts of N, N-dimethylacetamide, 28-30 parts of polyvinylpyrrolidone, 4-6 parts of ethanol, 0.1-0.2 part of zinc stearate and 0.5-1.0 part of calcium stearate.
Further, the upper functional surface layer is modified polyacrylic acid and is prepared from the following components in parts by weight: 3-7 parts of allyl polyethylene glycol, 6-8 parts of glycidyl methacrylate, 3-5 parts of butyl acrylate, 4-6 parts of isooctyl acrylate, 4-7 parts of vinyl acetate, 3-5 parts of acrylic acid, 8-12 parts of polyvinyl chloride, 3-5 parts of polyvinylidene fluoride, 1-4 parts of zinc acrylate resin and 56-72 parts of N, N-dimethylacetamide.
Further, the lower functional surface layer is modified polyvinylidene fluoride, and is prepared from the following components in parts by weight: 15-25 parts of polyvinyl chloride, 5-10 parts of polyvinylidene fluoride, 6-8 parts of acrylonitrile-butadiene-styrene copolymer, 3-7 parts of polyethylene glycol terephthalate fiber and 45-56 parts of N, N-dimethylacetamide.
Furthermore, the average pore diameter of the upper functional core layer is 68-75 nm, the average pore diameter of the upper functional surface layer is 3-26 nm, the average pore diameter of the lower functional core layer is 48-56 nm, and the average pore diameter of the lower functional surface layer is 12-30 nm.
In the technical scheme, the ultrafiltration membrane manufactured by the invention is determined to be composed of an upper functional layer and a lower functional layer, wherein the upper functional layer and the lower functional layer are both composed of a core layer and a surface layer, and the average pore diameters of pores in the upper functional core layer, the upper functional surface layer, the lower functional core layer and the lower functional surface layer are different, so that the pore structures of the functional surface layer and the functional core layer with gradually reduced pore diameters from top to bottom are formed, the water flow permeation is promoted, the filtration area is further improved, the improvement of the water treatment efficiency is facilitated, and the arrangement of the ultrafiltration membrane structure can provide a favorable basis for the improvement of the mechanical property.
A modified PVC hollow fiber ultrafiltration membrane and a preparation method thereof comprise the following steps:
(1) preparing a casting solution:
(a) preparing a casting solution A required by an upper functional core layer and a lower functional core layer;
(b) preparing a casting solution B required by the upper functional surface layer;
(c) preparing a membrane casting solution C required by the lower functional surface layer;
(2) and (4) preparing an ultrafiltration membrane.
Further, the step (a) includes the steps of:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at the temperature of 70-80 ℃ for 4-5 hours to prepare a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at the temperature of 60-80 ℃ for 7-8 hours to prepare a mixed solution E;
and (3) slowly adding the mixed solution A into the mixed solution B, stirring for 1-2 hours at the temperature of 70-80 ℃, filtering, and performing vacuum defoaming to obtain a casting solution A.
Further, the step (b) comprises the steps of:
adding allyl polyethylene glycol into deionized water, stirring, dissolving in deionized water, respectively adding glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid, and uniformly mixing to obtain a mixed solution F;
and (3) dissolving polyvinyl chloride, polyvinylidene fluoride and zinc acrylate resin in N, N-dimethylacetamide, stirring for 4-5 h at the temperature of 70-80 ℃, cooling to room temperature, adding the mixed solution F, and uniformly stirring to obtain a casting solution B.
Further, the step (c) comprises the steps of:
adding polyvinyl chloride, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer into N, N-dimethylacetamide, and stirring at 70-80 ℃ for 4-5 h to prepare a mixed solution G;
and (3) taking the polyethylene glycol terephthalate fiber, immersing the polyethylene glycol terephthalate fiber in N, N-dimethylacetamide for 18-24 h, and adding the mixed solution G to prepare a casting solution C.
In the technical scheme, modified polyvinyl chloride is used as an upper functional core layer and a lower functional core layer of the ultrafiltration membrane, wherein polyvinyl chloride, sulfonated polyether sulfone and polyvinylidene fluoride are used as base resin for preparing the ultrafiltration membrane, the polyvinyl chloride has good chemical stability, can resist heat, acid and alkali and microbial corrosion, the sulfonated polyether sulfone has good flexibility and hydrophilicity, and can endow the prepared ultrafiltration membrane with excellent basic performance by combining with the polyvinyl chloride, the polyvinylidene fluoride has excellent mechanical performance and solvent resistance, the comprehensive performance of the functional core layer is improved, and zinc stearate and calcium stearate are added into the polyvinyl chloride, so that the thermal stability of the prepared ultrafiltration membrane is improved; mixing N, N-dimethylacetamide, polyvinylpyrrolidone and ethanol to prepare a solvent of the membrane casting solution A, so that the prepared functional core layer forms finger-shaped pores, the porosity of the functional core layer is improved, and the water permeation of the prepared ultrafiltration membrane is realized;
polyvinyl chloride and polyvinylidene fluoride are used as base resin of the lower functional surface layer, acrylonitrile-butadiene-styrene copolymer and polyethylene glycol terephthalate fiber are added, the comprehensive performance of the prepared ultrafiltration membrane can be kept, the strength and toughness of the prepared lower functional surface layer are improved, and the lower functional surface layer with smaller pores is prepared by using N, N-dimethylacetamide as a solvent;
the upper functional surface layer is prepared by taking polyvinyl chloride, polyvinylidene fluoride and polyacrylic acid as base resin, so that the hydrophilicity and surface tension of the prepared ultrafiltration membrane can be improved, the ultrafiltration membrane is prevented from being polluted by pollutants during water treatment, the water treatment efficiency is improved, and the prepared ultrafiltration membrane is ensured to be effectively used for a long time.
Further, the step (2) comprises the following steps:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to obtain a hollow fiber membrane, and then soaking in water for 21-27 hours to complete gel curing to obtain a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer;
depositing the casting film liquid C on the upper surface of the lower functional core layer at the flow rate of 3-5 mL/h for 3-8 times to obtain a lower functional surface layer;
placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing for 10-30 min, adding an aminosilane coupling agent, and stirring at a constant temperature of 50-60 ℃ for 2-3 h to prepare modified calcium carbonate;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing, adding methanol, deionized water and dimethyl azodiisobutyrate into a reaction product, heating to 50-60 ℃, carrying out ultrasonic treatment for 10-30 min, and adding ethyl acetate and methanol into the reaction product to prepare a modified calcium carbonate solution;
and carrying out corona treatment on the upper functional core layer, adding benzoyl peroxide and modified calcium carbonate into the casting solution B, uniformly mixing, coating the mixture on the surface of the upper surface layer core layer, standing for 2-3 h at room temperature, heating to 70-80 ℃, keeping the temperature for 2-6 h, carrying out ultraviolet lamp irradiation, cleaning and drying, immersing the upper surface layer core layer in ethyl acetate, standing for 1-2 h at room temperature, coating a modified calcium carbonate solution after cleaning, heating to 70-80 ℃, keeping the temperature for 2-6 h, cleaning and drying to obtain an upper functional surface layer, and forming the ultrafiltration membrane.
In the technical scheme, firstly, an upper functional core layer and a lower functional core layer with different apertures are prepared by using a casting solution A, a casting solution C is deposited on the upper surface of the lower functional core layer to prepare a lower functional surface layer, and the lower functional surface layer is compounded with the upper functional core layer; adding benzoyl peroxide into the membrane casting solution B, coating the membrane casting solution B on the surface of the upper functional core layer, polymerizing monomer allyl polyethylene glycol, glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid in the membrane casting solution B, and crosslinking the monomer allyl polyethylene glycol, glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid with polyvinyl chloride, sulfonated polyether sulfone and polyvinylidene fluoride in the corona-treated upper functional core layer and lower functional surface layers under the irradiation of an ultraviolet lamp and a certain temperature environment, so that the bonding force among structural layers is enhanced, the brittleness of the prepared ultrafiltration membrane is improved by the aid of the modified calcium carbonate added in a synergistic manner, and the porosity and the water flux; and then swelling the prepared polyacrylic acid by using ethyl acetate, coating the modified calcium carbonate solution on the surface after cleaning, so that the dimethyl azodiisobutyrate modified calcium carbonate is embedded into pores formed by swelling, the pore diameter in the prepared upper functional surface layer is reduced, the porosity and water flux are maintained, and the rejection rate is improved.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the modified PVC hollow fiber ultrafiltration membrane and the preparation method thereof, the ultrafiltration membrane is determined to be composed of the upper functional layer and the lower functional layer by setting the structure of the prepared ultrafiltration membrane, the upper functional layer and the lower functional layer are both composed of the core layer and the surface layer, and the average pore diameters of pores in the upper functional core layer, the upper functional surface layer, the lower functional core layer and the lower functional surface layer are different, so that the pore structures of the functional surface layer and the functional core layer with gradually reduced pore diameters from top to bottom are formed, water flow permeation is promoted, the filtration area is further increased, the improvement of water treatment efficiency is facilitated, and the setting of the ultrafiltration membrane structure can provide a favorable basis for the improvement of the.
2. According to the modified PVC hollow fiber ultrafiltration membrane and the preparation method thereof, the components of the prepared ultrafiltration membrane are arranged, so that the prepared ultrafiltration membrane has excellent basic performance, the comprehensive performances of thermal stability, toughness and the like of the ultrafiltration membrane are improved, the required pores are formed by utilizing the structures of the membrane layers, the porosity is improved, the water permeation of the prepared ultrafiltration membrane is realized, the hydrophilicity and the surface tension of the prepared ultrafiltration membrane are improved, the ultrafiltration membrane is prevented from being polluted by pollutants during water treatment, the water treatment efficiency is improved, and the prepared ultrafiltration membrane is ensured to be effectively used for a long time.
3. According to the modified PVC hollow fiber ultrafiltration membrane and the preparation method thereof, the prepared ultrafiltration membrane is provided with the preparation process, so that the bonding force among all structural layers can be enhanced, the water treatment efficiency and the mechanical property of the prepared ultrafiltration membrane are improved, the surface aperture of the ultrafiltration membrane is reduced through the preparation process of the upper functional surface layer, the porosity and the water flux are kept, the rejection rate is improved, the surface strength of the prepared upper functional surface layer is improved, the brittleness of the prepared ultrafiltration membrane is improved, and the oxidation resistance of the ultrafiltration membrane is improved.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
(1) Preparing a casting solution:
(a) preparing a casting solution A required by the upper functional core layer and the lower functional core layer:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at 70 ℃ for 4h to obtain a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at 60 ℃ for 7 hours to obtain a mixed solution E;
slowly adding the mixed solution A into the mixed solution B, stirring for 1h at the temperature of 70 ℃, filtering, and performing vacuum defoaming to obtain a casting solution A;
at this time, the casting solution a contains: 10.5 parts of polyvinyl chloride, 1.5 parts of sulfonated polyether sulfone, 3 parts of polyvinylidene fluoride, 48 parts of N, N-dimethylacetamide, 28 parts of polyvinylpyrrolidone, 4 parts of ethanol, 0.1 part of zinc stearate and 0.5 part of calcium stearate; (b) preparing a casting solution B required by the upper functional surface layer:
adding allyl polyethylene glycol into deionized water, stirring, dissolving in deionized water, respectively adding glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid, and uniformly mixing to obtain a mixed solution F;
dissolving polyvinyl chloride, polyvinylidene fluoride and zinc acrylate resin in N, N-dimethylacetamide, stirring for 4h at the temperature of 70 ℃, cooling to room temperature, adding the mixed solution F, and uniformly stirring to obtain a casting solution B;
at this time, the casting solution B contains: 3 parts of allyl polyethylene glycol, 6 parts of glycidyl methacrylate, 3 parts of butyl acrylate, 4 parts of isooctyl acrylate, 4 parts of vinyl acetate, 3 parts of acrylic acid, 8 parts of polyvinyl chloride, 3 parts of polyvinylidene fluoride, 1 part of zinc acrylate resin and 56 parts of N, N-dimethylacetamide;
(c) preparing a casting solution C required by the lower functional surface layer:
adding polyvinyl chloride, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer into N, N-dimethylacetamide, and stirring at 70 ℃ for 4 hours to prepare a mixed solution G;
soaking the polyethylene glycol terephthalate fiber in N, N-dimethylacetamide for 18 times, and adding the mixed solution G to prepare a casting solution C;
at this time, the casting solution C contains: 15 parts of polyvinyl chloride, 5 parts of polyvinylidene fluoride, 6 parts of acrylonitrile-butadiene-styrene copolymer, 3 parts of polyethylene glycol terephthalate fiber and 45 parts of N, N-dimethylacetamide;
(2) preparing an ultrafiltration membrane:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to prepare a hollow fiber membrane, and then soaking in water for 21 hours to complete gel curing to prepare a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer;
depositing the casting solution C on the upper surface of the lower functional core layer at the flow rate of 3mL/h for 3 times to obtain a lower functional surface layer;
placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing for 10min, adding an aminosilane coupling agent, and stirring at a constant temperature of 50 ℃ for 2h to prepare modified calcium carbonate;
adding calcium carbonate into a sodium hydroxide solution and sodium dodecyl sulfate, carrying out ultrasonic crushing, adding methanol, deionized water and dimethyl azodiisobutyrate into a reaction product, heating to 50 ℃, carrying out ultrasonic treatment for 10min, and adding ethyl acetate and methanol into the reaction product to prepare a modified calcium carbonate solution;
and carrying out corona treatment on the upper functional core layer, adding benzoyl peroxide and modified calcium carbonate into the casting solution B, uniformly mixing, coating the mixture on the surface of the upper surface layer core layer, standing for 2 hours at room temperature, heating to 70 ℃, keeping the temperature for 2 hours, carrying out irradiation of an ultraviolet lamp, cleaning and drying, immersing the upper surface layer core layer in ethyl acetate, standing for 1 hour at room temperature, coating a modified calcium carbonate solution after cleaning, heating to 70 ℃, keeping the temperature for 2 hours, cleaning and drying to obtain an upper functional surface layer, and forming the ultrafiltration membrane.
Example 2
(1) Preparing a casting solution:
(a) preparing a casting solution A required by the upper functional core layer and the lower functional core layer:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at 75 ℃ for 4.5h to obtain a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at 70 ℃ for 7.5 hours to obtain a mixed solution E;
slowly adding the mixed solution A into the mixed solution B, stirring for 1.5h at the temperature of 75 ℃, filtering, and performing vacuum defoaming to obtain a casting solution A;
at this time, the casting solution a contains: 12 parts of polyvinyl chloride, 3 parts of sulfonated polyether sulfone, 4 parts of polyvinylidene fluoride, 52 parts of N, N-dimethylacetamide, 29 parts of polyvinylpyrrolidone, 5 parts of ethanol, 0.15 part of zinc stearate and 0.7 part of calcium stearate;
(b) preparing a casting solution B required by the upper functional surface layer:
adding allyl polyethylene glycol into deionized water, stirring, dissolving in deionized water, respectively adding glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid, and uniformly mixing to obtain a mixed solution F;
dissolving polyvinyl chloride, polyvinylidene fluoride and zinc acrylate resin in N, N-dimethylacetamide, stirring for 4.5h at the temperature of 75 ℃, cooling to room temperature, adding the mixed solution F, and uniformly stirring to obtain a casting solution B;
at this time, the casting solution B contains: 5 parts of allyl polyethylene glycol, 7 parts of glycidyl methacrylate, 4 parts of butyl acrylate, 5 parts of isooctyl acrylate, 6 parts of vinyl acetate, 4 parts of acrylic acid, 10 parts of polyvinyl chloride, 4 parts of polyvinylidene fluoride, 2 parts of zinc acrylate resin and 64 parts of N, N-dimethylacetamide;
(c) preparing a casting solution C required by the lower functional surface layer:
adding polyvinyl chloride, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer into N, N-dimethylacetamide, and stirring at 75 ℃ for 4.5 hours to prepare a mixed solution G;
taking polyethylene glycol terephthalate fiber, immersing in N, N-dimethylacetamide for 21h, and adding the mixed solution G to prepare a casting solution C;
at this time, the casting solution C contains: 20 parts of polyvinyl chloride, 7 parts of polyvinylidene fluoride, 7 parts of acrylonitrile-butadiene-styrene copolymer, 5 parts of polyethylene glycol terephthalate fiber and 50 parts of N, N-dimethylacetamide;
(2) preparing an ultrafiltration membrane:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to prepare a hollow fiber membrane, and then soaking in water for 24 hours to complete gel curing to prepare a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer;
depositing the casting solution C on the upper surface of the lower functional core layer at the flow rate of 4mL/h for 5 times to obtain a lower functional surface layer;
placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing for 20min, adding an aminosilane coupling agent, and stirring at the constant temperature of 55 ℃ for 2.5h to prepare modified calcium carbonate;
adding calcium carbonate into a sodium hydroxide solution and sodium dodecyl sulfate, carrying out ultrasonic crushing, adding methanol, deionized water and dimethyl azodiisobutyrate into a reaction product, heating to 55 ℃, carrying out ultrasonic treatment for 20min, adding ethyl acetate and methanol into the reaction product, and preparing a modified calcium carbonate solution;
and carrying out corona treatment on the upper functional core layer, adding benzoyl peroxide and modified calcium carbonate into the casting solution B, uniformly mixing, coating the mixture on the surface of the upper surface layer core layer, standing at room temperature for 2.5h, heating to 75 ℃, keeping the temperature for 4h, carrying out irradiation of an ultraviolet lamp, cleaning and drying, immersing the upper surface layer core layer in ethyl acetate, standing at room temperature for 1.5h, coating a modified calcium carbonate solution after cleaning, heating to 75 ℃, keeping the temperature for 4h, cleaning and drying to obtain an upper functional surface layer, and forming the ultrafiltration membrane.
Example 3
(1) Preparing a casting solution:
(a) preparing a casting solution A required by the upper functional core layer and the lower functional core layer:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at 80 ℃ for 5 hours to obtain a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at 80 ℃ for 8 hours to obtain a mixed solution E;
slowly adding the mixed solution A into the mixed solution B, stirring for 2 hours at the temperature of 80 ℃, filtering, and performing vacuum defoaming to obtain a casting solution A;
at this time, the casting solution a contains: 13.5 parts of polyvinyl chloride, 4.5 parts of sulfonated polyether sulfone, 5 parts of polyvinylidene fluoride, 56 parts of N, N-dimethylacetamide, 30 parts of polyvinylpyrrolidone, 6 parts of ethanol, 0.2 part of zinc stearate and 1.0 part of calcium stearate; (b) preparing a casting solution B required by the upper functional surface layer:
adding allyl polyethylene glycol into deionized water, stirring, dissolving in deionized water, respectively adding glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid, and uniformly mixing to obtain a mixed solution F;
dissolving polyvinyl chloride, polyvinylidene fluoride and zinc acrylate resin in N, N-dimethylacetamide, stirring at 80 ℃ for 5h, cooling to room temperature, adding the mixed solution F, and uniformly stirring to obtain a casting solution B;
at this time, the casting solution B contains: 7 parts of allyl polyethylene glycol, 8 parts of glycidyl methacrylate, 5 parts of butyl acrylate, 6 parts of isooctyl acrylate, 7 parts of vinyl acetate, 5 parts of acrylic acid, 12 parts of polyvinyl chloride, 5 parts of polyvinylidene fluoride, 4 parts of zinc acrylate resin and 72 parts of N, N-dimethylacetamide;
(c) preparing a casting solution C required by the lower functional surface layer:
adding polyvinyl chloride, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer into N, N-dimethylacetamide, and stirring at 80 ℃ for 5 hours to prepare a mixed solution G;
soaking the polyethylene glycol terephthalate fiber in N, N-dimethylacetamide for 24h, and adding the mixed solution G to prepare a casting solution C;
at this time, the casting solution C contains: 25 parts of polyvinyl chloride, 10 parts of polyvinylidene fluoride, 8 parts of acrylonitrile-butadiene-styrene copolymer, 7 parts of polyethylene glycol terephthalate fiber and 56 parts of N, N-dimethylacetamide;
(2) preparing an ultrafiltration membrane:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to prepare a hollow fiber membrane, and then soaking in water for 27 hours to complete gel curing to prepare a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer;
depositing the casting solution C on the upper surface of the lower functional core layer at the flow rate of 5mL/h for 8 times to obtain a lower functional surface layer;
placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing for 30min, adding an aminosilane coupling agent, and stirring at a constant temperature of 60 ℃ for 3h to prepare modified calcium carbonate;
adding calcium carbonate into a sodium hydroxide solution and sodium dodecyl sulfate, carrying out ultrasonic crushing, adding methanol, deionized water and dimethyl azodiisobutyrate into a reaction product, heating to 60 ℃, carrying out ultrasonic treatment for 30min, adding ethyl acetate and methanol into the reaction product, and preparing a modified calcium carbonate solution;
and carrying out corona treatment on the upper functional core layer, adding benzoyl peroxide and modified calcium carbonate into the casting solution B, uniformly mixing, coating the mixture on the surface of the upper surface layer core layer, standing for 3 hours at room temperature, heating to 80 ℃, keeping the temperature for 6 hours, irradiating by an ultraviolet lamp, cleaning and drying, immersing the upper surface layer core layer in ethyl acetate, standing for 2 hours at room temperature, coating a modified calcium carbonate solution after cleaning, heating to 80 ℃, keeping the temperature for 6 hours, cleaning and drying to obtain an upper functional surface layer, and forming the ultrafiltration membrane.
Comparative example 1
(1) Preparing a casting solution:
(a) preparing a casting solution A required by the upper functional core layer and the lower functional core layer:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at 75 ℃ for 4.5h to obtain a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at 70 ℃ for 7.5 hours to obtain a mixed solution E;
slowly adding the mixed solution A into the mixed solution B, stirring for 1.5h at the temperature of 75 ℃, filtering, and performing vacuum defoaming to obtain a casting solution A;
at this time, the casting solution a contains: 12 parts of polyvinyl chloride, 3 parts of sulfonated polyether sulfone, 4 parts of polyvinylidene fluoride, 52 parts of N, N-dimethylacetamide, 29 parts of polyvinylpyrrolidone, 5 parts of ethanol, 0.15 part of zinc stearate and 0.7 part of calcium stearate;
(b) preparing a casting solution B required by the lower functional surface layer:
adding polyvinyl chloride, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer into N, N-dimethylacetamide, and stirring at 75 ℃ for 4.5 hours to prepare a mixed solution G;
taking polyethylene glycol terephthalate fiber, immersing the polyethylene glycol terephthalate fiber in N, N-dimethylacetamide for 21 hours, and adding the mixed solution G to prepare a casting solution B;
at this time, the casting solution B contains: 20 parts of polyvinyl chloride, 7 parts of polyvinylidene fluoride, 7 parts of acrylonitrile-butadiene-styrene copolymer, 5 parts of polyethylene glycol terephthalate fiber and 50 parts of N, N-dimethylacetamide;
(2) preparing an ultrafiltration membrane:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to prepare a hollow fiber membrane, and then soaking in water for 24 hours to complete gel curing to prepare a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer;
depositing the casting solution B on the upper surface of the lower functional core layer at the flow rate of 4mL/h for 5 times to obtain a lower functional surface layer;
and placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding to form the ultrafiltration membrane.
Comparative example 2
(1) Preparing a casting solution:
(a) preparing a casting solution A required by the upper functional core layer and the lower functional core layer:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at 75 ℃ for 4.5h to obtain a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at 70 ℃ for 7.5 hours to obtain a mixed solution E;
slowly adding the mixed solution A into the mixed solution B, stirring for 1.5h at the temperature of 75 ℃, filtering, and performing vacuum defoaming to obtain a casting solution A;
at this time, the casting solution a contains: 12 parts of polyvinyl chloride, 3 parts of sulfonated polyether sulfone, 4 parts of polyvinylidene fluoride, 52 parts of N, N-dimethylacetamide, 29 parts of polyvinylpyrrolidone, 5 parts of ethanol, 0.15 part of zinc stearate and 0.7 part of calcium stearate;
(b) preparing a casting solution B required by the upper functional surface layer:
adding allyl polyethylene glycol into deionized water, stirring, dissolving in deionized water, respectively adding glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid, and uniformly mixing to obtain a mixed solution F;
dissolving polyvinyl chloride, polyvinylidene fluoride and zinc acrylate resin in N, N-dimethylacetamide, stirring for 4.5h at the temperature of 75 ℃, cooling to room temperature, adding the mixed solution F, and uniformly stirring to obtain a casting solution B;
at this time, the casting solution B contains: 5 parts of allyl polyethylene glycol, 7 parts of glycidyl methacrylate, 4 parts of butyl acrylate, 5 parts of isooctyl acrylate, 6 parts of vinyl acetate, 4 parts of acrylic acid, 10 parts of polyvinyl chloride, 4 parts of polyvinylidene fluoride, 2 parts of zinc acrylate resin and 64 parts of N, N-dimethylacetamide;
(2) preparing an ultrafiltration membrane:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to prepare a hollow fiber membrane, and then soaking in water for 24 hours to complete gel curing to prepare a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer; placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing for 20min, adding an aminosilane coupling agent, and stirring at the constant temperature of 55 ℃ for 2.5h to prepare modified calcium carbonate;
adding calcium carbonate into a sodium hydroxide solution and sodium dodecyl sulfate, carrying out ultrasonic crushing, adding methanol, deionized water and dimethyl azodiisobutyrate into a reaction product, heating to 55 ℃, carrying out ultrasonic treatment for 20min, adding ethyl acetate and methanol into the reaction product, and preparing a modified calcium carbonate solution;
and carrying out corona treatment on the upper functional core layer, adding benzoyl peroxide and modified calcium carbonate into the casting solution B, uniformly mixing, coating the mixture on the surface of the upper surface layer core layer, standing at room temperature for 2.5h, heating to 75 ℃, keeping the temperature for 4h, carrying out irradiation of an ultraviolet lamp, cleaning and drying, immersing the upper surface layer core layer in ethyl acetate, standing at room temperature for 1.5h, coating a modified calcium carbonate solution after cleaning, heating to 75 ℃, keeping the temperature for 4h, cleaning and drying to obtain an upper functional surface layer, and forming the ultrafiltration membrane.
Comparative example 3
(1) Preparing a casting solution:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at 75 ℃ for 4.5h to obtain a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at 70 ℃ for 7.5 hours to obtain a mixed solution E;
slowly adding the mixed solution A into the mixed solution B, stirring for 1.5h at the temperature of 75 ℃, filtering, and performing vacuum defoaming to obtain a membrane casting solution;
at this time, the casting solution contains: 12 parts of polyvinyl chloride, 3 parts of sulfonated polyether sulfone, 4 parts of polyvinylidene fluoride, 52 parts of N, N-dimethylacetamide, 29 parts of polyvinylpyrrolidone, 5 parts of ethanol, 0.15 part of zinc stearate and 0.7 part of calcium stearate;
(2) preparing an ultrafiltration membrane:
and (3) taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to obtain a hollow fiber membrane, and then soaking in water for 24 hours to complete gel curing to obtain the ultrafiltration membrane.
Comparative example 4
(1) Preparing a casting solution:
(a) preparing a casting solution A required by the upper functional core layer and the lower functional core layer:
dissolving polyvinyl chloride in N, N-dimethylacetamide, filtering, and performing vacuum defoaming to obtain a casting solution A;
at this time, the casting solution a contains: 12 parts of polyvinyl chloride and 52 parts of N, N-dimethylacetamide;
(b) preparing a casting solution B required by the upper functional surface layer:
adding allyl polyethylene glycol into deionized water, stirring, dissolving in deionized water, respectively adding glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid, and uniformly mixing to obtain a mixed solution F;
dissolving polyvinyl chloride, polyvinylidene fluoride and zinc acrylate resin in N, N-dimethylacetamide, stirring for 4.5h at the temperature of 75 ℃, cooling to room temperature, adding the mixed solution F, and uniformly stirring to obtain a casting solution B;
at this time, the casting solution B contains: 5 parts of allyl polyethylene glycol, 7 parts of glycidyl methacrylate, 4 parts of butyl acrylate, 5 parts of isooctyl acrylate, 6 parts of vinyl acetate, 4 parts of acrylic acid, 10 parts of polyvinyl chloride, 4 parts of polyvinylidene fluoride, 2 parts of zinc acrylate resin and 64 parts of N, N-dimethylacetamide;
(c) preparing a casting solution C required by the lower functional surface layer:
adding polyvinyl chloride, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer into N, N-dimethylacetamide, and stirring at 75 ℃ for 4.5 hours to prepare a mixed solution G;
taking polyethylene glycol terephthalate fiber, immersing in N, N-dimethylacetamide for 21h, and adding the mixed solution G to prepare a casting solution C;
at this time, the casting solution C contains: 20 parts of polyvinyl chloride, 7 parts of polyvinylidene fluoride, 7 parts of acrylonitrile-butadiene-styrene copolymer, 5 parts of polyethylene glycol terephthalate fiber and 50 parts of N, N-dimethylacetamide;
(2) preparing an ultrafiltration membrane:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to prepare a hollow fiber membrane, and then soaking in water for 24 hours to complete gel curing to prepare a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer;
depositing the casting solution C on the upper surface of the lower functional core layer at the flow rate of 4mL/h for 5 times to obtain a lower functional surface layer;
placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing for 20min, adding an aminosilane coupling agent, and stirring at the constant temperature of 55 ℃ for 2.5h to prepare modified calcium carbonate;
adding calcium carbonate into a sodium hydroxide solution and sodium dodecyl sulfate, carrying out ultrasonic crushing, adding methanol, deionized water and dimethyl azodiisobutyrate into a reaction product, heating to 55 ℃, carrying out ultrasonic treatment for 20min, adding ethyl acetate and methanol into the reaction product, and preparing a modified calcium carbonate solution;
and carrying out corona treatment on the upper functional core layer, adding benzoyl peroxide and modified calcium carbonate into the casting solution B, uniformly mixing, coating the mixture on the surface of the upper surface layer core layer, standing at room temperature for 2.5h, heating to 75 ℃, keeping the temperature for 4h, carrying out irradiation of an ultraviolet lamp, cleaning and drying, immersing the upper surface layer core layer in ethyl acetate, standing at room temperature for 1.5h, coating a modified calcium carbonate solution after cleaning, heating to 75 ℃, keeping the temperature for 4h, cleaning and drying to obtain an upper functional surface layer, and forming the ultrafiltration membrane.
Comparative example 5
(1) Preparing a casting solution:
(a) preparing a casting solution A required by the upper functional core layer and the lower functional core layer:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at 75 ℃ for 4.5h to obtain a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at 70 ℃ for 7.5 hours to obtain a mixed solution E;
slowly adding the mixed solution A into the mixed solution B, stirring for 1.5h at the temperature of 75 ℃, filtering, and performing vacuum defoaming to obtain a casting solution A;
at this time, the casting solution a contains: 12 parts of polyvinyl chloride, 3 parts of sulfonated polyether sulfone, 4 parts of polyvinylidene fluoride, 52 parts of N, N-dimethylacetamide, 29 parts of polyvinylpyrrolidone, 5 parts of ethanol, 0.15 part of zinc stearate and 0.7 part of calcium stearate;
(b) preparing a casting solution B required by the upper functional surface layer:
adding allyl polyethylene glycol into deionized water, stirring, dissolving in deionized water, respectively adding glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid, and uniformly mixing to obtain a mixed solution F;
dissolving polyvinyl chloride, polyvinylidene fluoride and zinc acrylate resin in N, N-dimethylacetamide, stirring for 4.5h at the temperature of 75 ℃, cooling to room temperature, adding the mixed solution F, and uniformly stirring to obtain a casting solution B;
at this time, the casting solution B contains: 5 parts of allyl polyethylene glycol, 7 parts of glycidyl methacrylate, 4 parts of butyl acrylate, 5 parts of isooctyl acrylate, 6 parts of vinyl acetate, 4 parts of acrylic acid, 10 parts of polyvinyl chloride, 4 parts of polyvinylidene fluoride, 2 parts of zinc acrylate resin and 64 parts of N, N-dimethylacetamide;
(c) preparing a casting solution C required by the lower functional surface layer:
adding polyvinyl chloride, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer into N, N-dimethylacetamide, and stirring at 75 ℃ for 4.5 hours to prepare a mixed solution G;
taking polyethylene glycol terephthalate fiber, immersing in N, N-dimethylacetamide for 21h, and adding the mixed solution G to prepare a casting solution C;
at this time, the casting solution C contains: 20 parts of polyvinyl chloride, 7 parts of polyvinylidene fluoride, 7 parts of acrylonitrile-butadiene-styrene copolymer, 5 parts of polyethylene glycol terephthalate fiber and 50 parts of N, N-dimethylacetamide;
(2) preparing an ultrafiltration membrane:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to prepare a hollow fiber membrane, and then soaking in water for 24 hours to complete gel curing to prepare a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer;
depositing the casting solution C on the upper surface of the lower functional core layer at the flow rate of 4mL/h for 5 times to obtain a lower functional surface layer;
placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding;
and carrying out corona treatment on the upper functional core layer, adding benzoyl peroxide into the casting solution B, uniformly mixing, coating on the surface of the upper surface core layer, standing at room temperature for 2.5h, heating to 75 ℃, keeping the temperature for 4h, carrying out ultraviolet lamp irradiation, cleaning and drying to obtain an upper functional surface layer, and forming the ultrafiltration membrane.
Experiment of
Taking the ultrafiltration membranes obtained in the examples 1-3 and the comparative examples 1-5 to prepare samples, respectively detecting the water treatment capacity and the mechanical property of the samples, and recording the detection results:
wherein the water treatment capacity is determined by using water flux and rejection rate of the sample as indexes, the water flux is water temperature of 25 deg.C, water pressure of 0.1MPa, unit time (1h), unit membrane area (1 m)2) The volume of pure water permeated;
the tensile strength and the elongation of the mechanical property test sample are used as indexes, and the test is carried out by using ASTM D-648 and ASTM D-638 as test standards;
from the data in the table above, it is clear that the following conclusions can be drawn:
the ultrafiltration membranes obtained in examples 1 to 3 and comparative examples 1 to 5 were compared, and it was found from the results of the measurement that:
1. compared with the ultrafiltration membrane obtained in the comparative example 3, the retention rate, tensile strength and elongation data of the ultrafiltration membranes obtained in the examples 1 to 3 are obviously improved, and the water flux data is slightly reduced, so that the water treatment capacity and the mechanical property of the prepared ultrafiltration membrane can be improved;
2. compared with the ultrafiltration membrane obtained in the comparative example 1, the ultrafiltration membrane obtained in the comparative example 1 is not provided with the upper functional surface layer, and the retention rate, tensile strength and elongation data of the ultrafiltration membrane are slightly reduced compared with those of the ultrafiltration membrane obtained in the example 2, so that the arrangement of the upper functional surface layer has a promoting effect on the water treatment capacity and the mechanical property of the prepared ultrafiltration membrane;
3. compared with the ultrafiltration membrane obtained in the comparative example 2, the ultrafiltration membrane obtained in the comparative example 2 is not provided with the lower functional surface layer, the retention rate, tensile strength and elongation data of the ultrafiltration membrane are slightly reduced compared with those of the ultrafiltration membrane obtained in the example 2, and the arrangement of the upper functional surface layer in the ultrafiltration membrane has a promoting effect on the water treatment capacity and the mechanical property of the prepared ultrafiltration membrane;
4. compared with the ultrafiltration membrane obtained in the comparative example 4, the ultrafiltration membrane obtained in the comparative example 4 has the advantages that the upper functional core layer and the lower functional core layer are not modified, the retention rate, the tensile strength and the elongation data of the ultrafiltration membrane are slightly reduced compared with those of the ultrafiltration membrane obtained in the example 2, and the modification of the upper functional core layer and the lower functional core layer has a promoting effect on the water treatment capacity and the mechanical property of the prepared ultrafiltration membrane;
5. in example 2, compared with the ultrafiltration membrane obtained in comparative example 5, the upper functional surface layer was not treated in comparative example 5, and the retention rate, tensile strength and elongation data were slightly reduced compared with example 2, which indicates that the treatment process of the upper functional surface layer in the present invention has an effect of promoting the water treatment capacity and mechanical properties of the ultrafiltration membrane.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A modified PVC hollow fiber ultrafiltration membrane is characterized in that: the ultrafiltration membrane comprises an upper functional layer and a lower functional layer, the upper functional layer comprises an upper functional core layer and an upper functional surface layer, the lower functional layer comprises a lower functional core layer and a lower functional surface layer, the upper functional core layer is located below the upper functional surface layer, the upper functional core layer is located above the lower functional surface layer, the lower functional core layer is located below the lower functional surface layer, and the upper functional core layer and the lower functional surface layer are made of modified polyvinyl chloride.
2. The modified PVC hollow fiber ultrafiltration membrane of claim 1, wherein: the upper functional core layer and the lower functional core layer are prepared from the following components in parts by weight: 10.5-13.5 parts of polyvinyl chloride, 1.5-4.5 parts of sulfonated polyether sulfone, 3-5 parts of polyvinylidene fluoride, 48-56 parts of N, N-dimethylacetamide, 28-30 parts of polyvinylpyrrolidone, 4-6 parts of ethanol, 0.1-0.2 part of zinc stearate and 0.5-1.0 part of calcium stearate.
3. The modified PVC hollow fiber ultrafiltration membrane of claim 1, wherein: the upper functional surface layer is modified polyacrylic acid and is prepared from the following components in parts by weight: 3-7 parts of allyl polyethylene glycol, 6-8 parts of glycidyl methacrylate, 3-5 parts of butyl acrylate, 4-6 parts of isooctyl acrylate, 4-7 parts of vinyl acetate, 3-5 parts of acrylic acid, 8-12 parts of polyvinyl chloride, 3-5 parts of polyvinylidene fluoride, 1-4 parts of zinc acrylate resin and 56-72 parts of N, N-dimethylacetamide.
4. The modified PVC hollow fiber ultrafiltration membrane of claim 1, wherein: the lower functional surface layer is modified polyvinylidene fluoride and is prepared from the following components in parts by weight: 15-25 parts of polyvinyl chloride, 5-10 parts of polyvinylidene fluoride, 6-8 parts of acrylonitrile-butadiene-styrene copolymer, 3-7 parts of polyethylene glycol terephthalate fiber and 45-56 parts of N, N-dimethylacetamide.
5. A preparation method of a modified PVC hollow fiber ultrafiltration membrane is characterized by comprising the following steps:
(1) preparing a casting solution:
(a) preparing a casting solution A required by an upper functional core layer and a lower functional core layer;
(b) preparing a casting solution B required by the upper functional surface layer;
(c) preparing a membrane casting solution C required by the lower functional surface layer;
(2) and (4) preparing an ultrafiltration membrane.
6. The preparation method of the modified PVC hollow fiber ultrafiltration membrane according to claim 5, which is characterized in that: the step (a) includes the steps of:
dissolving polyvinyl chloride and sulfonated polyether sulfone in N, N-dimethylacetamide, adding zinc stearate and calcium stearate, and stirring at the temperature of 70-80 ℃ for 4-5 hours to prepare a mixed solution D;
taking N, N-dimethylacetamide, adding polyvinylpyrrolidone, blending, adding polyvinylidene fluoride for dissolving, adding ethanol, uniformly mixing, and stirring at the temperature of 60-80 ℃ for 7-8 hours to prepare a mixed solution E;
and (3) slowly adding the mixed solution A into the mixed solution B, stirring for 1-2 hours at the temperature of 70-80 ℃, filtering, and performing vacuum defoaming to obtain a casting solution A.
7. The method for preparing the modified PVC hollow fiber ultrafiltration membrane according to claim 5, wherein the step (b) comprises the following steps:
adding allyl polyethylene glycol into deionized water, stirring, dissolving in deionized water, respectively adding glycidyl methacrylate, butyl acrylate, isooctyl acrylate, vinyl acetate and acrylic acid, and uniformly mixing to obtain a mixed solution F;
and (3) dissolving polyvinyl chloride, polyvinylidene fluoride and zinc acrylate resin in N, N-dimethylacetamide, stirring for 4-5 h at the temperature of 70-80 ℃, cooling to room temperature, adding the mixed solution F, and uniformly stirring to obtain a casting solution B.
8. The method for preparing the modified PVC hollow fiber ultrafiltration membrane according to claim 5, wherein the step (c) comprises the following steps:
adding polyvinyl chloride, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer into N, N-dimethylacetamide, and stirring at 70-80 ℃ for 4-5 h to prepare a mixed solution G;
and (3) taking the polyethylene glycol terephthalate fiber, immersing the polyethylene glycol terephthalate fiber in N, N-dimethylacetamide for 18-24 h, and adding the mixed solution G to prepare a casting solution C.
9. The preparation method of the modified PVC hollow fiber ultrafiltration membrane according to claim 5, wherein the step (2) comprises the following steps:
taking the membrane casting solution A, spinning by using a hollow fiber spinning machine to obtain a hollow fiber membrane, and then soaking in water for 21-27 hours to complete gel curing to obtain a lower functional core layer;
taking the casting solution A again, and repeating the steps to obtain an upper functional core layer;
depositing the casting film liquid C on the upper surface of the lower functional core layer at the flow rate of 3-5 mL/h for 3-8 times to obtain a lower functional surface layer;
placing the upper functional core layer on the top of the lower functional surface layer, and performing thermal compounding;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing for 10-30 min, adding an aminosilane coupling agent, and stirring at a constant temperature of 50-60 ℃ for 2-3 h to prepare modified calcium carbonate;
adding a sodium hydroxide solution and sodium dodecyl sulfate into calcium carbonate, carrying out ultrasonic crushing, adding methanol, deionized water and dimethyl azodiisobutyrate into a reaction product, heating to 50-60 ℃, carrying out ultrasonic treatment for 10-30 min, and adding ethyl acetate and methanol into the reaction product to prepare a modified calcium carbonate solution;
and carrying out corona treatment on the upper functional core layer, adding benzoyl peroxide and modified calcium carbonate into the casting solution B, uniformly mixing, coating the mixture on the surface of the upper surface layer core layer, standing for 2-3 h at room temperature, heating to 70-80 ℃, keeping the temperature for 2-6 h, carrying out ultraviolet lamp irradiation, cleaning and drying, immersing the upper surface layer core layer in ethyl acetate, standing for 1-2 h at room temperature, coating a modified calcium carbonate solution after cleaning, heating to 70-80 ℃, keeping the temperature for 2-6 h, cleaning and drying to obtain an upper functional surface layer, and forming the ultrafiltration membrane.
10. The preparation method of the modified PVC hollow fiber ultrafiltration membrane according to claim 9, characterized in that: the average pore diameter of the upper functional core layer is 68-75 nm, the average pore diameter of the upper functional surface layer is 3-26 nm, the average pore diameter of the lower functional core layer is 48-56 nm, and the average pore diameter of the lower functional surface layer is 12-30 nm.
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