阅读说明：本技术 一种石墨烯复合聚丙烯腈中空纤维膜及其制备方法 (Graphene composite polyacrylonitrile hollow fiber membrane and preparation method thereof ) 是由 任国峰 马立国 刘少华 于 2021-01-15 设计创作，主要内容包括：本发明公开了一种石墨烯复合聚丙烯腈中空纤维膜及其制备方法,其原料包含：聚丙烯腈粉20％～50％,氧化石墨烯溶液0.1％～15％,改性剂0.1％～1％,致孔剂10％～20％,溶剂30％～60％；致孔剂为无机盐、聚乙二醇、氰基丙烯酸乙酯按质量比为1:(2-4):(1-2)的混合物。改性剂为聚乙二醇、十二烷基吡咯烷酮、聚乙烯吡络烷酮、硅烷偶联剂的混合物,其质量比为1:(2-4):(3-5):(1-2)。本发明还提供了该石墨烯复合聚丙烯腈中空纤维膜的制备方法。本发明制备的纤维膜强度高,过滤效率高,不仅能够去除水中悬浮颗粒物、重金属、胶体等还能够去除水中的细菌和病原体。(The invention discloses a graphene composite polyacrylonitrile hollow fiber membrane and a preparation method thereof, wherein the graphene composite polyacrylonitrile hollow fiber membrane comprises the following raw materials: 20-50% of polyacrylonitrile powder, 0.1-15% of graphene oxide solution, 0.1-1% of modifier, 10-20% of pore-foaming agent and 30-60% of solvent; the pore-foaming agent is a mixture of inorganic salt, polyethylene glycol and ethyl cyanoacrylate according to a mass ratio of 1 (2-4) to (1-2). The modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinyl pyrrolidone and a silane coupling agent, and the mass ratio of the modifier to the silane coupling agent is 1 (2-4) to (3-5) to (1-2). The invention also provides a preparation method of the graphene composite polyacrylonitrile hollow fiber membrane. The fiber membrane prepared by the method has high strength and high filtering efficiency, and can remove suspended particles, heavy metals, colloids and the like in water and also remove bacteria and pathogens in the water.)

1. The graphene composite polyacrylonitrile hollow fiber membrane is characterized by comprising the following raw materials in percentage by mass: 20-50% of polyacrylonitrile powder, 0.1-15% of graphene oxide solution, 0.1-1% of modifier, 10-20% of pore-foaming agent and 30-60% of solvent; the pore-foaming agent is inorganic salt, polyethylene glycol and ethyl cyanoacrylate, and the mass ratio of the pore-foaming agent to the ethyl cyanoacrylate is 1 (2-4):

the mixture of (1-2).

2. The graphene composite polyacrylonitrile hollow fiber membrane according to claim 1, wherein the graphene oxide solution is prepared by graphene oxide and deionized water; the graphene of the graphene oxide is prepared by any one of a mechanical stripping method, a liquid phase stripping method, a chemical vapor deposition method and a redox method.

3. The graphene composite polyacrylonitrile hollow fiber membrane of claim 1, wherein the modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinyl pyrrolidone and a silane coupling agent, and the mass ratio of the modifier to the silane coupling agent is 1 (2-4) to (3-5) to (1-2).

4. The graphene composite polyacrylonitrile hollow fiber membrane according to claim 1, wherein the solvent is DMF.

5. A preparation method of the graphene composite polyacrylonitrile hollow fiber membrane as claimed in any one of claims 1 to 4, characterized by comprising the following steps:

step 1, weighing raw materials in proportion;

step 2, preparing a graphene oxide solution to obtain functional graphene slurry;

step 3, adding the functional graphene slurry and the modifier obtained in the step 2 into a DMF solvent, stirring, performing ultrasonic treatment, adding polyacrylonitrile powder and a pore-forming agent, swelling, heating, and stirring to prepare a membrane casting solution;

step 4, adding the membrane casting solution prepared in the step 3 into a reaction kettle, filtering and defoaming, removing insoluble substances, bubbles and impurities, starting to discharge materials, adopting dry-wet spinning, spinning membrane filaments, passing through an air channel, then entering a coagulating bath, washing with water, and soaking in a deionized water extraction bath at room temperature;

and 5, stretching the product obtained in the step 4 in a water bath twice, and drying the obtained membrane filaments to obtain the graphene composite polyacrylonitrile hollow fiber membrane.

6. The preparation method of the graphene composite polyacrylonitrile hollow fiber membrane according to claim 5, wherein in the step 2, graphene oxide powder is weighed and dispersed in deionized water, stirred for 20-40 min at normal temperature, and then subjected to ultrasonic treatment for 30-60 min to obtain functional graphene slurry; the mass concentration of the graphene oxide powder in deionized water is 1-15%.

7. The preparation method of the graphene composite polyacrylonitrile hollow fiber membrane according to claim 5, wherein in the step 3, the functional graphene slurry and the modifier are added into a DMF solvent, fully stirred for 15-30 min, then subjected to ultrasonic treatment for 20-40 min, added with polyacrylonitrile powder and a pore-forming agent, swelled at 40-60 ℃ for 30-50 min, heated to 70-80 ℃ and stirred for 1-2 h, and a membrane casting solution is prepared.

8. The preparation method of the graphene composite polyacrylonitrile hollow fiber membrane according to claim 5, wherein in the step 4, the membrane casting solution is added into a reaction kettle at the temperature of 60-80 ℃, filtration and defoaming are carried out, insoluble substances, bubbles and impurities are removed, discharging is started, dry-wet spinning is adopted, and the spun membrane filaments firstly pass through an air channel with the length of 5-10 cm and then enter a coagulation bath; the membrane filament hole is circular and adopts DMF/H₂An O gradient coagulation bath, wherein the mass ratio of the gradient is (50-60): 35-40), (50-55): 60-70); and (3) washing the product with water, and soaking the product in a deionized water extraction bath for 2-5 hours at room temperature.

9. The preparation method of the graphene composite polyacrylonitrile hollow fiber membrane according to claim 5, wherein in the step 5, the product is stretched twice in a water bath at 50-60 ℃ and 85-95 ℃, and the stretching times are 3-4 times and 2-3 times respectively.

10. The preparation method of the graphene composite polyacrylonitrile hollow fiber membrane as claimed in claim 5, wherein in the step 5, the obtained membrane filaments are dried, and the inner diameter of the membrane filaments is 0.8-1.5 mm, and the outer diameter of the membrane filaments is 2.1-2.5 mm.

Technical Field

The invention relates to a graphene fiber membrane and a preparation method thereof, in particular to a graphene composite polyacrylonitrile hollow fiber membrane and a preparation method thereof.

Background

Graphene is a single-layer carbon atom material stripped from graphite, and a single-layer two-dimensional honeycomb lattice structure is formed by tightly packing carbon atoms, and is known to be the material with the thinnest thickness, the hardest texture and the best conductivity. Graphene has excellent mechanical, optical and electrical properties and a very stable structure, researchers have not found that graphene has a missing carbon atom, the linkage between carbon atoms is very flexible, and is harder than diamond, the strength is 100 times higher than that of the world's best steel, if graphene is used for making a packaging bag, the graphene can bear about two tons of articles, the graphene is almost completely transparent, but is very compact, waterproof and airtight, helium gas with the minimum atomic size cannot pass through the graphene, the graphene has good conductivity, the movement speed of electrons in graphene reaches 1/300 of the light speed, the conductivity exceeds that of any traditional conductive material, the chemical properties are similar to the surface of graphite, various atoms and molecules can be adsorbed and desorbed, and the graphene also has the capability of resisting strong acid and strong alkali. Meanwhile, the graphene also has an excellent antibacterial function, and can be applied to a water purification hollow fiber membrane to effectively avoid bacterial breeding and prevent secondary pollution.

Disclosure of Invention

The invention aims to provide a graphene fiber membrane and a preparation method thereof, wherein modified graphene is fused, so that suspended particles, colloid and heavy metal particles in water can be filtered, bacteria and pathogens can be blocked, the graphene has the functions of antibiosis and bacteriostasis, secondary pollution of water quality is avoided, the quality of drinking water is ensured to be in a high-quality state all the time, and the health of people is protected.

In order to achieve the purpose, the invention provides a graphene composite polyacrylonitrile hollow fiber membrane, wherein the hollow fiber membrane comprises the following raw materials in percentage by mass: 20-50% of Polyacrylonitrile (PAN) powder, 0.1-15% of graphene oxide solution, 0.1-1% of modifier, 10-20% of pore-foaming agent and 30-60% of solvent; the pore-foaming agent is a mixture of inorganic salt, polyethylene glycol and ethyl cyanoacrylate according to a mass ratio of 1 (2-4) to (1-2).

The graphene composite polyacrylonitrile hollow fiber membrane is characterized in that the graphene oxide solution is prepared from graphene oxide and deionized water; the graphene of the graphene oxide is prepared by any one of methods such as a mechanical stripping method, a liquid-phase stripping method, a chemical vapor deposition method and a redox method.

The graphene composite polyacrylonitrile hollow fiber membrane is characterized in that the modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinylpyrrolidone (PVP) and a silane coupling agent in a mass ratio of (2) - (4) - (3-5) - (1-2).

The graphene composite polyacrylonitrile hollow fiber membrane is characterized in that the solvent is DMF (dimethyl formamide).

The invention also provides a preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, wherein the method comprises the following steps: step 1, weighing raw materials in proportion; step 2, preparing a graphene oxide solution to obtain functional graphene slurry; step 3, adding the functional graphene slurry and the modifier obtained in the step 2 into a DMF solvent, stirring, performing ultrasonic treatment, adding polyacrylonitrile powder and a pore-forming agent, swelling, heating, and stirring to prepare a membrane casting solution; step 4, adding the membrane casting solution prepared in the step 3 into a reaction kettle, filtering and defoaming, removing insoluble substances, bubbles and impurities, starting to discharge materials, adopting dry-wet spinning, spinning membrane filaments, passing through an air channel, then entering a coagulating bath, washing with water, and soaking in a deionized water extraction bath at room temperature; and 5, stretching the product obtained in the step 4 in a water bath twice, and drying the obtained membrane filaments to obtain the graphene composite polyacrylonitrile hollow fiber membrane.

In the preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, in the step 2, graphene oxide powder is weighed and dispersed in deionized water, stirred at normal temperature for 20-40 min, and then subjected to ultrasonic treatment for 30-60 min to obtain functional graphene slurry; the mass concentration of the graphene oxide powder in deionized water is 1-15%.

In the step 3, the functional graphene slurry and the modifier are added into a DMF solvent, fully stirred for 15-30 min, subjected to ultrasonic treatment for 20-40 min, added with polyacrylonitrile powder and a pore-forming agent, swelled at 40-60 ℃ for 30-50 min, heated to 70-80 ℃ and stirred for 1-2 h to prepare the casting solution.

The preparation method of the graphene composite polyacrylonitrile hollow fiber membrane comprises the following steps of (4) adding the membrane casting solution into a reaction kettle at the temperature of 60-80 ℃, filtering and defoaming, removing insoluble substances, bubbles and impurities, starting to discharge materials, spinning by adopting a dry-wet method, passing the spun membrane filaments through an air channel with the length of 5-10 cm, and then entering a coagulating bath; the membrane wire holes are circular, and DMF/H2O gradient coagulation bath is adopted, and the gradient mass ratio is (50-60): 35-40), (50-55): 60-70 respectively; and (3) washing the product with water, and soaking the product in a deionized water extraction bath for 2-5 hours at room temperature.

In the step 5, the product is stretched twice in a water bath at 50-60 ℃ and 85-95 ℃, and the stretching times are 3-4 times and 2-3 times respectively.

In the preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, in the step 5, the obtained membrane filaments are dried, and the inner diameter of the membrane filaments is 0.8-1.5 mm, and the outer diameter of the membrane filaments is 2.1-2.5 mm.

The graphene composite polyacrylonitrile hollow fiber membrane and the preparation method thereof provided by the invention have the following advantages:

the graphene functional hollow fiber membrane prepared by the method has high strength and high filtration efficiency, wherein the pore diameter of the membrane is less than 0.01 micron, so that not only can suspended particles, heavy metals, colloids and the like in water be removed, but also bacteria and pathogens in the water can be removed, the removal rate reaches 99.9%, and the water quality after treatment is completely combined with the national drinking standard.

The functional graphene hollow fiber membrane prepared by the method has the advantages of simple process, easy operation, low cost and high economic benefit, and is suitable for large-scale industrial production.

Detailed Description

The following further describes embodiments of the present invention.

The graphene composite polyacrylonitrile hollow fiber membrane provided by the invention comprises the following raw materials in percentage by mass: 20-50% of Polyacrylonitrile (PAN) powder, 0.1-15% of graphene oxide solution, 0.1-1% of modifier, 10-20% of pore-foaming agent and 30-60% of solvent.

Preferably, the pore-foaming agent is a mixture of inorganic salt, polyethylene glycol and ethyl cyanoacrylate according to a mass ratio of 1 (2-4) to (1-2).

Preparing a graphene oxide solution by using graphene oxide and deionized water; graphene of graphene oxide is prepared by any one of methods such as a mechanical exfoliation method, a liquid-phase exfoliation method, a chemical vapor deposition method, and a redox method.

The modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinylpyrrolidone (PVP) and a silane coupling agent, and the mass ratio of the modifier to the silane coupling agent is 1 (2-4) to (3-5) to (1-2).

The solvent was DMF (dimethylformamide).

The invention also provides a preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, which comprises the following steps:

step 1, weighing raw materials in proportion; step 2, preparing a graphene oxide solution to obtain functional graphene slurry; step 3, adding the functional graphene slurry and the modifier obtained in the step 2 into a DMF solvent, stirring, performing ultrasonic treatment, adding polyacrylonitrile powder and a pore-forming agent, swelling, heating, and stirring to prepare a membrane casting solution; step 4, adding the membrane casting solution prepared in the step 3 into a reaction kettle, filtering and defoaming, removing insoluble substances, bubbles, impurities and the like, starting to discharge materials, adopting dry-wet spinning, spinning membrane filaments, passing through an air channel, then entering a coagulating bath, washing with water, and soaking in a deionized water extraction bath at room temperature; and 5, stretching the product obtained in the step 4 in a water bath twice, and drying the obtained membrane filaments to obtain the graphene composite polyacrylonitrile hollow fiber membrane.

Preferably, in the step 2, graphene oxide powder is weighed and dispersed in deionized water, stirred for 20-40 min at normal temperature, and then subjected to ultrasonic treatment for 30-60 min to obtain functional graphene slurry; the mass concentration of the graphene oxide powder in deionized water is 1-15%.

And 3, adding the functional graphene slurry and the modifier into a DMF (dimethyl formamide) solvent, fully stirring for 15-30 min, performing ultrasonic treatment for 20-40 min, adding polyacrylonitrile powder and a pore-forming agent, swelling for 30-50 min at 40-60 ℃, heating to 70-80 ℃, stirring for 1-2 h, and preparing the membrane casting solution.

Adding the membrane casting solution into a reaction kettle at the temperature of 60-80 ℃, filtering, defoaming, removing insoluble substances, bubbles and impurities, starting discharging, adopting dry-wet spinning, and spinning membrane filaments to pass through an air channel with the length of 5-10 cm and then enter a coagulating bath; the membrane wire holes are circular, and DMF/H2O gradient coagulation bath is adopted, and the gradient mass ratio is (50-60): 35-40), (50-55): 60-70 respectively; and (3) washing the product with water, and soaking the product in a deionized water extraction bath for 2-5 hours at room temperature.

And step 5, respectively stretching the product twice in water baths at 50-60 ℃ and 85-95 ℃, wherein the stretching times are respectively 3-4 times and 2-3 times.

The graphene composite polyacrylonitrile hollow fiber membrane and the preparation method thereof provided by the invention are further described below with reference to the embodiments.

Example 1

A graphene composite polyacrylonitrile hollow fiber membrane comprises the following raw materials in percentage by mass: 49.8% of Polyacrylonitrile (PAN) powder, 0.1% of graphene oxide solution, 0.1% of modifier, 20% of pore-forming agent and 30% of solvent.

The pore-foaming agent is a mixture of inorganic salt, polyethylene glycol and ethyl cyanoacrylate according to a mass ratio of 1:2: 1.

The modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinylpyrrolidone (PVP) and a silane coupling agent in a mass ratio of 1:2:3: 1.

The graphene oxide solution is prepared from graphene oxide and deionized water; the graphene of the graphene oxide is prepared by a mechanical stripping method.

The solvent was DMF (dimethylformamide).

The embodiment also provides a preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, which comprises the following steps:

step 1, weighing the raw materials in proportion.

And 2, preparing a graphene oxide solution to obtain the functional graphene slurry.

Weighing graphene oxide powder, dispersing the graphene oxide powder in deionized water, stirring for 20-40 min at a normal temperature, and then carrying out ultrasonic treatment for 30-60 min to obtain functional graphene slurry; the mass concentration of the graphene oxide powder in deionized water is 1%.

And 3, adding the functional graphene slurry and the modifier obtained in the step 2 into a DMF solvent, fully stirring for 15-30 min, performing ultrasonic treatment for 20-40 min, adding polyacrylonitrile powder and a pore-forming agent, swelling for 30-50 min at 40-60 ℃, heating to 70-80 ℃, and stirring for 1-2 h to prepare a casting solution.

Step 4, adding the membrane casting solution prepared in the step 3 into a reaction kettle at the temperature of 60-80 ℃, filtering and defoaming, removing insoluble substances, bubbles, impurities and the like, starting discharging, adopting dry-wet spinning, and spinning membrane filaments to pass through an air channel with the length of 5-10 cm and then enter a coagulating bath; the membrane wire holes are circular, and DMF/H2O gradient coagulation bath is adopted, and the gradient mass ratio is (50-60): 35-40), (50-55): 60-70 respectively; washing the product with water, and soaking the product in a deionized water extraction bath at room temperature for 2-5 h;

and 5, stretching the product obtained in the step 4 twice in a water bath at the temperature of 50-60 ℃ and 85-95 ℃, wherein the stretching times are 3-4 times and 2-3 times respectively. And drying the obtained membrane filaments to obtain the graphene composite polyacrylonitrile hollow fiber membrane. The inner diameter of the membrane wire is 0.8-1.5 mm, and the outer diameter is 2.1-2.5 mm.

Example 2

A graphene composite polyacrylonitrile hollow fiber membrane comprises the following raw materials in percentage by mass: 50% of Polyacrylonitrile (PAN) powder, 1% of graphene oxide solution, 0.8% of a modifier, 11% of a pore-forming agent and 37.2% of a solvent.

The pore-foaming agent is a mixture of inorganic salt, polyethylene glycol and ethyl cyanoacrylate according to a mass ratio of 1:2.5: 1.

The modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinylpyrrolidone (PVP) and a silane coupling agent in a mass ratio of 1:2.5:3.5: 1.

The graphene oxide solution is prepared from graphene oxide and deionized water; the graphene of the graphene oxide is prepared by a liquid phase stripping method.

The solvent was DMF (dimethylformamide).

The embodiment also provides a preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, which comprises the following steps:

step 1, weighing the raw materials in proportion.

And 2, preparing a graphene oxide solution to obtain the functional graphene slurry.

Weighing graphene oxide powder, dispersing the graphene oxide powder in deionized water, stirring for 20-40 min at a normal temperature, and then carrying out ultrasonic treatment for 30-60 min to obtain functional graphene slurry; the mass concentration of the graphene oxide powder in deionized water is 3%.

And 3, adding the functional graphene slurry and the modifier obtained in the step 2 into a DMF solvent, fully stirring for 15-30 min, performing ultrasonic treatment for 20-40 min, adding polyacrylonitrile powder and a pore-forming agent, swelling for 30-50 min at 40-60 ℃, heating to 70-80 ℃, and stirring for 1-2 h to prepare a casting solution.

Step 4, adding the membrane casting solution prepared in the step 3 into a reaction kettle at the temperature of 60-80 ℃, filtering and defoaming, removing insoluble substances, bubbles, impurities and the like, starting discharging, adopting dry-wet spinning, and spinning membrane filaments to pass through an air channel with the length of 5-10 cm and then enter a coagulating bath; the membrane wire holes are circular, and DMF/H2O gradient coagulation bath is adopted, and the gradient mass ratio is (50-60): 35-40), (50-55): 60-70 respectively; washing the product with water, and soaking the product in a deionized water extraction bath at room temperature for 2-5 h;

and 5, stretching the product obtained in the step 4 twice in a water bath at the temperature of 50-60 ℃ and 85-95 ℃, wherein the stretching times are 3-4 times and 2-3 times respectively. And drying the obtained membrane filaments to obtain the graphene composite polyacrylonitrile hollow fiber membrane. The inner diameter of the membrane wire is 0.8-1.5 mm, and the outer diameter is 2.1-2.5 mm.

Example 3

A graphene composite polyacrylonitrile hollow fiber membrane comprises the following raw materials in percentage by mass: 24.7% of Polyacrylonitrile (PAN) powder, 3% of graphene oxide solution, 0.3% of a modifier, 12% of a pore-foaming agent and 60% of a solvent.

The pore-foaming agent is a mixture of inorganic salt, polyethylene glycol and ethyl cyanoacrylate according to a mass ratio of 1:3: 1.5.

The modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinylpyrrolidone (PVP) and a silane coupling agent in a mass ratio of 1:3:4: 1.5.

The graphene oxide solution is prepared from graphene oxide and deionized water; the graphene of the graphene oxide is prepared by a chemical vapor deposition method.

The solvent was DMF (dimethylformamide).

The embodiment also provides a preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, which comprises the following steps:

step 1, weighing the raw materials in proportion.

And 2, preparing a graphene oxide solution to obtain the functional graphene slurry.

Weighing graphene oxide powder, dispersing the graphene oxide powder in deionized water, stirring for 20-40 min at a normal temperature, and then carrying out ultrasonic treatment for 30-60 min to obtain functional graphene slurry; the mass concentration of the graphene oxide powder in the deionized water is 8%.

And 3, adding the functional graphene slurry and the modifier obtained in the step 2 into a DMF solvent, fully stirring for 15-30 min, performing ultrasonic treatment for 20-40 min, adding polyacrylonitrile powder and a pore-forming agent, swelling for 30-50 min at 40-60 ℃, heating to 70-80 ℃, and stirring for 1-2 h to prepare a casting solution.

Step 4, adding the membrane casting solution prepared in the step 3 into a reaction kettle at the temperature of 60-80 ℃, filtering and defoaming, removing insoluble substances, bubbles, impurities and the like, starting discharging, adopting dry-wet spinning, and spinning membrane filaments to pass through an air channel with the length of 5-10 cm and then enter a coagulating bath; the membrane wire holes are circular, and DMF/H2O gradient coagulation bath is adopted, and the gradient mass ratio is (50-60): 35-40), (50-55): 60-70 respectively; washing the product with water, and soaking the product in a deionized water extraction bath at room temperature for 2-5 h;

and 5, stretching the product obtained in the step 4 twice in a water bath at the temperature of 50-60 ℃ and 85-95 ℃, wherein the stretching times are 3-4 times and 2-3 times respectively. And drying the obtained membrane filaments to obtain the graphene composite polyacrylonitrile hollow fiber membrane. The inner diameter of the membrane wire is 0.8-1.5 mm, and the outer diameter is 2.1-2.5 mm.

Example 4

A graphene composite polyacrylonitrile hollow fiber membrane comprises the following raw materials in percentage by mass: 30% of Polyacrylonitrile (PAN) powder, 7% of graphene oxide solution, 0.5% of a modifier, 15% of a pore-forming agent and 47.5% of a solvent.

The pore-foaming agent is a mixture of inorganic salt, polyethylene glycol and ethyl cyanoacrylate according to a mass ratio of 1:3.5: 2.

The modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinylpyrrolidone (PVP) and a silane coupling agent in a mass ratio of 1:3.5:4.5: 2.

The graphene oxide solution is prepared from graphene oxide and deionized water; the graphene of the graphene oxide is prepared by adopting a redox method.

The solvent was DMF (dimethylformamide).

The embodiment also provides a preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, which comprises the following steps:

step 1, weighing the raw materials in proportion.

And 2, preparing a graphene oxide solution to obtain the functional graphene slurry.

Weighing graphene oxide powder, dispersing the graphene oxide powder in deionized water, stirring for 20-40 min at a normal temperature, and then carrying out ultrasonic treatment for 30-60 min to obtain functional graphene slurry; the mass concentration of the graphene oxide powder in the deionized water is 12%.

And 3, adding the functional graphene slurry and the modifier obtained in the step 2 into a DMF solvent, fully stirring for 15-30 min, performing ultrasonic treatment for 20-40 min, adding polyacrylonitrile powder and a pore-forming agent, swelling for 30-50 min at 40-60 ℃, heating to 70-80 ℃, and stirring for 1-2 h to prepare a casting solution.

Step 4, adding the membrane casting solution prepared in the step 3 into a reaction kettle at the temperature of 60-80 ℃, filtering and defoaming, removing insoluble substances, bubbles, impurities and the like, starting discharging, adopting dry-wet spinning, and spinning membrane filaments to pass through an air channel with the length of 5-10 cm and then enter a coagulating bath; the membrane wire holes are circular, and DMF/H2O gradient coagulation bath is adopted, and the gradient mass ratio is (50-60): 35-40), (50-55): 60-70 respectively; washing the product with water, and soaking the product in a deionized water extraction bath at room temperature for 2-5 h;

and 5, stretching the product obtained in the step 4 twice in a water bath at the temperature of 50-60 ℃ and 85-95 ℃, wherein the stretching times are 3-4 times and 2-3 times respectively. And drying the obtained membrane filaments to obtain the graphene composite polyacrylonitrile hollow fiber membrane. The inner diameter of the membrane wire is 0.8-1.5 mm, and the outer diameter is 2.1-2.5 mm.

Example 5

A graphene composite polyacrylonitrile hollow fiber membrane comprises the following raw materials in percentage by mass: 20% of Polyacrylonitrile (PAN) powder, 15% of graphene oxide solution, 1% of modifier, 10% of pore-forming agent and 54% of solvent.

The pore-foaming agent is a mixture of inorganic salt, polyethylene glycol and ethyl cyanoacrylate according to a mass ratio of 1:4: 2.

The modifier is a mixture of polyethylene glycol, dodecyl pyrrolidone, polyvinylpyrrolidone (PVP) and a silane coupling agent in a mass ratio of 1:4:5: 2.

The graphene oxide solution is prepared from graphene oxide and deionized water; the graphene of the graphene oxide is prepared by a mechanical stripping method or a redox method.

The solvent was DMF (dimethylformamide).

The embodiment also provides a preparation method of the graphene composite polyacrylonitrile hollow fiber membrane, which comprises the following steps:

step 1, weighing the raw materials in proportion.

And 2, preparing a graphene oxide solution to obtain the functional graphene slurry.

Weighing graphene oxide powder, dispersing the graphene oxide powder in deionized water, stirring for 20-40 min at a normal temperature, and then carrying out ultrasonic treatment for 30-60 min to obtain functional graphene slurry; the mass concentration of the graphene oxide powder in the deionized water is 15%.

And 3, adding the functional graphene slurry and the modifier obtained in the step 2 into a DMF solvent, fully stirring for 15-30 min, performing ultrasonic treatment for 20-40 min, adding polyacrylonitrile powder and a pore-forming agent, swelling for 30-50 min at 40-60 ℃, heating to 70-80 ℃, and stirring for 1-2 h to prepare a casting solution.

Step 4, adding the membrane casting solution prepared in the step 3 into a reaction kettle at the temperature of 60-80 ℃, filtering and defoaming, removing insoluble substances, bubbles, impurities and the like, starting discharging, adopting dry-wet spinning, and spinning membrane filaments to pass through an air channel with the length of 5-10 cm and then enter a coagulating bath; the membrane wire holes are circular, and DMF/H2O gradient coagulation bath is adopted, and the gradient mass ratio is (50-60): 35-40), (50-55): 60-70 respectively; washing the product with water, and soaking the product in a deionized water extraction bath at room temperature for 2-5 h;

and 5, stretching the product obtained in the step 4 twice in a water bath at the temperature of 50-60 ℃ and 85-95 ℃, wherein the stretching times are 3-4 times and 2-3 times respectively. And drying the obtained membrane filaments to obtain the graphene composite polyacrylonitrile hollow fiber membrane. The inner diameter of the membrane wire is 0.8-1.5 mm, and the outer diameter is 2.1-2.5 mm.

The invention provides a graphene composite polyacrylonitrile hollow fiber membrane and a preparation method thereof, which are characterized in that functional graphene slurry is added into a polyacrylonitrile membrane casting solution, the solution contains a pore-forming agent with a certain concentration, and the functional graphene slurry system can be well mixed with the polyacrylonitrile membrane casting solution. The invention aims to produce a graphene polyacrylonitrile hollow fiber membrane material by utilizing a graphene solution preparation and dispersion system and a polyacrylonitrile hollow fiber membrane production process, the graphene hollow fiber membrane is fused with modified graphene, not only can filter suspended particulate matters, colloids and heavy metal particles in water, but also can obstruct bacteria and pathogens, simultaneously plays a role in graphene antibiosis and bacteriostasis, avoids secondary pollution of water quality, ensures that the water quality of drinking water is always in a high-quality state, and protects the health of people. The graphene hollow fiber membrane can also greatly prolong the service life and reduce the use cost.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.