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CN-122006518-A - Hollow fiber water treatment ultrafiltration membrane and preparation method thereof

CN122006518ACN 122006518 ACN122006518 ACN 122006518ACN-122006518-A

Abstract

The invention relates to a hollow fiber water treatment ultrafiltration membrane and a preparation method thereof, belonging to the technical field of hollow fiber ultrafiltration, wherein the hollow fiber water treatment ultrafiltration membrane is of a hollow external pressure membrane wire structure, the pore size of the outer surface of the hollow fiber water treatment ultrafiltration membrane is 6-12nm, the pore size of the inner surface of the hollow fiber water treatment ultrafiltration membrane is 10-16nm, the thickness of the side wall of the hollow fiber water treatment ultrafiltration membrane is 2.5-5.5 mu m, and the hollow fiber water treatment ultrafiltration membrane is obtained by extruding a casting membrane liquid by a spinning device. The plant-based carbon powder and the mineral-based carbon powder are compounded to form a synergistic modification effect, and compared with the traditional technology, the hydrophilic modified carbon powder and the mineral-based carbon powder can not only remarkably improve the hydrophilicity, pore structure uniformity and mechanical property of the membrane, but also effectively optimize the pore canal penetrability and surface wettability of the membrane by virtue of the characteristics of high specific surface area and rich surface functional groups of the plant-based carbon powder, and the mineral-based carbon powder can enhance the structural compactness and mechanical bearing capacity of the membrane.

Inventors

  • LIU XI
  • JIA XIAOJUN
  • GUAN JIMING
  • SUN JI

Assignees

  • 河南菲特膜新材料有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. The hollow fiber water treatment ultrafiltration membrane is characterized by having a hollow external pressure membrane wire structure, wherein the pore size of the outer surface of the hollow fiber water treatment ultrafiltration membrane is 6-12nm, the pore size of the inner surface of the hollow fiber water treatment ultrafiltration membrane is 10-16nm, and the thickness of the side wall of the hollow fiber water treatment ultrafiltration membrane is 2.5-5.5 mu m; the hollow fiber water treatment ultrafiltration membrane is obtained by extruding a membrane casting solution through a spinning device; The preparation materials of the casting film solution comprise, by weight, 32-45 parts of polymer, 3-10 parts of pore-forming agent, 1-3 parts of plant-based carbon powder, 2-5 parts of mineral-based carbon powder, 20-26 parts of hydrophilic emulsion, 25-35 parts of polar aprotic solvent and 45-55 parts of deionized water; The preparation raw materials of the hydrophilic emulsion comprise, by weight, 15-23 parts of acrylic acid, 3-6 parts of acrylamide, 2-4 parts of tween 80, 0.1-0.5 part of fatty alcohol polyoxyethylene ether, 2-5 parts of glycerol, 0.5-2 parts of ethylene glycol dimethacrylate, 1-3 parts of ammonium persulfate, 5-8 parts of sodium bicarbonate and 30-45 parts of deionized water.
  2. 2. A hollow fiber water treatment ultrafiltration membrane according to claim 1, wherein the pore size of the outer surface of the hollow fiber water treatment ultrafiltration membrane is preferably 8-10nm.
  3. 3. A hollow fiber water treatment ultrafiltration membrane according to claim 1, wherein the pore size of the inner surface of the hollow fiber water treatment ultrafiltration membrane is preferably 12-14nm.
  4. 4. A hollow fiber water treatment ultrafiltration membrane according to claim 1, wherein the thickness of the hollow fiber water treatment ultrafiltration membrane sidewall is preferably 3.0-4.0 μm.
  5. 5. The hollow fiber water treatment ultrafiltration membrane according to claim 1, wherein the pore-forming agent is polyvinylpyrrolidone or polyethylene glycol.
  6. 6. The hollow fiber water treatment ultrafiltration membrane of claim 1 wherein the polymer is selected from one of polyvinylidene fluoride, polyethersulfone, and polysulfone.
  7. 7. The hollow fiber water treatment ultrafiltration membrane according to claim 1, wherein the plant-based carbon powder is prepared from 20-32 parts by weight of coconut shells, 5-10 parts by weight of bamboo chips, 16-24 parts by weight of rice hulls and 30-45 parts by weight of wheat straw.
  8. 8. The hollow fiber water treatment ultrafiltration membrane according to claim 1, wherein the mineral-based carbon powder is prepared from, by weight, 18-26 parts of natural crystalline flake graphite, 30-45 parts of volcanic rock, 12-18 parts of volcanic ash and 1-5 parts of vermiculite.
  9. 9. The hollow fiber water treatment ultrafiltration membrane of claim 1, wherein the polar aprotic solvent is one of N, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone.
  10. 10. A method for preparing the hollow fiber water treatment ultrafiltration membrane according to any one of claims 1 to 9, comprising the steps of: The preparation of plant-based carbon powder comprises the following steps of (1) mixing coconut shells, bamboo scraps, rice hulls and wheat straws, and placing the mixture in an oven at 80-105 ℃ for drying for 6-12 hours, wherein the water content is controlled to be less than or equal to 5%, so as to obtain a mixed plant material; crushing the mixed plant material into 3-10mm particles by adopting a crusher, conveying the particles into carbonization equipment, heating to 500-600 ℃ at a heating rate of 3-5 ℃ per min under the protection of nitrogen atmosphere, and preserving heat for 1.5-3h to obtain crude plant carbon; Soaking the crude plant carbon in 5% -10% dilute hydrochloric acid for 2-4h, taking out the crude plant carbon after soaking, washing the crude plant carbon with deionized water to pH6.0-7.0, drying the crude plant carbon for 4-6h at 105 ℃ after washing, and grinding the crude plant carbon to the particle size D50=1-5 mu m to obtain plant-based carbon powder; firstly, coarsely crushing volcanic rock to 5-10mm particles by using a jaw crusher, mixing the particles with natural crystalline flake graphite, volcanic ash and vermiculite, and placing the mixture in a 105 ℃ oven for drying for 4-6 hours, wherein the moisture is controlled to be less than or equal to 1%, so as to obtain a mixed mineral material; Grinding the mixed ore material to 100-200 meshes by adopting a ball milling mode, placing the mixed ore material in a crucible, placing the crucible in a muffle furnace under the protection of nitrogen atmosphere, heating to 550-750 ℃ at a heating rate of 3-5 ℃ per minute, and preserving heat for 1-2h to obtain crude mineral carbon powder; Soaking crude mineral carbon powder in 5% -10% dilute hydrochloric acid for 2-4h, taking out the crude mineral carbon powder after soaking, washing the crude mineral carbon powder with deionized water to pH6.5-7.5, drying the crude mineral carbon powder for 3-5h at 105 ℃ after washing, and grinding the crude mineral carbon powder to the particle size D50=1-5 mu m to obtain mineral-based carbon powder; Adding deionized water into a reaction kettle, starting stirring, controlling the rotating speed at 300-500r/min, sequentially adding tween 80 and fatty alcohol-polyoxyethylene ether, stirring for 15-20min, adding sodium bicarbonate, continuously stirring for 10-15min, adjusting the pH to 6.5-7.5 by using citric acid, then adding glycerol, continuously stirring for 5-10min, adding acrylic acid, acrylamide and ethylene glycol dimethacrylate after stirring is finished, and continuously stirring for 30-40min to obtain the pre-prepared emulsion; Heating the reaction kettle to 70-80 ℃, preserving heat for 5-10min to ensure the stability of the system temperature, slowly dripping 35% ammonium persulfate aqueous solution through a constant pressure dripping funnel at a dripping speed of 1-2 drops/second, stirring at a rotating speed of 300-500r/min in the dripping process, keeping the reaction temperature at 70-80 ℃ after the 35% ammonium persulfate aqueous solution is dripped, adjusting the stirring rotating speed of 300-500r/min, stirring for 3-5h, closing a heating device after the stirring is finished, naturally cooling to room temperature of 25-28 ℃, and keeping the stirring speed at 100-200r/min in the period to obtain the hydrophilic emulsion; Adding plant-based carbon powder and mineral-based carbon powder into 1/3 of hydrophilic emulsion, wherein the ultrasonic power is 200-500W frequency and stirring speed is 20-40kHz, and the stirring speed is 200-300r/min, and dispersing for 40-60min for 30min to obtain carbon slurry; Step two, adding a polar aprotic solvent into a stirring kettle, starting stirring, controlling the rotating speed to be 200-300r/min, controlling the temperature to be 40-50 ℃, adding a polymer and a pore-foaming agent, and stirring for 2-3 hours to obtain a polymer solution; Slowly adding the carbon slurry prepared in the step (1) into a polymer solution, dispersing for 40-60min at an ultrasonic power of 200-500W at a frequency of 20-40kHz and a stirring rotation speed of 200-300r/min, adding the rest hydrophilic emulsion and deionized water, regulating the stirring rotation speed to 300-400r/min, continuing stirring for 1-2h, transferring to a vacuum deaerator after stirring, controlling the vacuum degree to be-0.08-0.1 MPa, deaerating for 30-60min, and standing and curing for 2-4h to obtain the casting film liquid; And step four, extruding the casting solution through a spinning device to obtain the hollow fiber water treatment ultrafiltration membrane.

Description

Hollow fiber water treatment ultrafiltration membrane and preparation method thereof Technical Field The invention belongs to the technical field of hollow fiber ultrafiltration, and particularly relates to a hollow fiber water treatment ultrafiltration membrane and a preparation method thereof. Background The hollow fiber ultrafiltration is a membrane separation technology based on a high molecular separation membrane, the core element is a hollow fiber ultrafiltration membrane, and the micropores of the tube wall can retain substances with molecular weight of thousands to hundreds of thousands. The technology realizes dynamic filtration through external pressure or internal pressure type pressurized flow, has the characteristics of low-pressure operation, high flux, low energy consumption and the like, and is widely applied to the fields of water treatment, biological pharmacy, food and beverage purification and the like. The traditional hollow fiber water treatment ultrafiltration membrane completes pore-forming molding by means of a single type of pore-forming agent, internal pore canal arrangement is disordered and unordered, distribution is extremely uneven, the membrane body structure is completely lack of internal and external pore diameter gradient design layout, meanwhile, the compactness of a membrane surface skin layer is poor, structural flaws such as micro micropore defects, local oversized pores and penetrating cracks are extremely easy to exist in the membrane body after the preparation molding, further, the bubble point pressure of a membrane wire is directly low, the integral structural integrity is seriously insufficient, and adverse phenomena of permeation leakage and short flow of water flow are extremely easy to occur in the long-term operation working condition of actual water treatment. Disclosure of Invention The invention aims to solve the problems and provide a hollow fiber water treatment ultrafiltration membrane and a preparation method thereof. The invention realizes the above purpose through the following technical scheme: The invention provides a hollow fiber water treatment ultrafiltration membrane which is of a hollow external pressure membrane wire structure, wherein the pore size of the outer surface of the hollow fiber water treatment ultrafiltration membrane is 6-12nm, the pore size of the inner surface of the hollow fiber water treatment ultrafiltration membrane is 10-16nm, and the thickness of the side wall of the hollow fiber water treatment ultrafiltration membrane is 2.5-5.5 mu m; the hollow fiber water treatment ultrafiltration membrane is obtained by extruding a membrane casting solution through a spinning device; The preparation materials of the casting film solution comprise, by weight, 32-45 parts of polymer, 3-10 parts of pore-forming agent, 1-3 parts of plant-based carbon powder, 2-5 parts of mineral-based carbon powder, 20-26 parts of hydrophilic emulsion, 25-35 parts of polar aprotic solvent and 45-55 parts of deionized water; The preparation raw materials of the hydrophilic emulsion comprise, by weight, 15-23 parts of acrylic acid, 3-6 parts of acrylamide, 2-4 parts of tween 80, 0.1-0.5 part of fatty alcohol polyoxyethylene ether, 2-5 parts of glycerol, 0.5-2 parts of ethylene glycol dimethacrylate, 1-3 parts of ammonium persulfate, 5-8 parts of sodium bicarbonate and 30-45 parts of deionized water. As a further optimization scheme of the invention, the pore size of the outer surface of the hollow fiber water treatment ultrafiltration membrane is preferably 8-10nm. As a further optimization scheme of the invention, the pore size of the inner surface of the hollow fiber water treatment ultrafiltration membrane is preferably 12-14nm. As a further optimization scheme of the invention, the thickness of the side wall of the hollow fiber water treatment ultrafiltration membrane is preferably 3.0-4.0 mu m. As a further optimization scheme of the invention, the pore-foaming agent adopts polyvinylpyrrolidone or polyethylene glycol. As a further optimization scheme of the invention, the polymer is selected from one of polyvinylidene fluoride, polyethersulfone and polysulfone. As a further optimization scheme of the invention, the plant-based carbon powder is prepared from the following raw materials, by weight, 20-32 parts of coconut shells, 5-10 parts of bamboo scraps, 16-24 parts of rice hulls and 30-45 parts of wheat straw. According to a further optimization scheme of the invention, the mineral-based carbon powder is prepared from, by weight, 18-26 parts of natural crystalline flake graphite, 30-45 parts of volcanic rock, 12-18 parts of volcanic ash and 1-5 parts of vermiculite. As a further optimization scheme of the invention, the polar aprotic solvent adopts one of N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone. The invention also provides a preparation method of the hollow fiber water treatment ultrafiltration membrane, which comprises