CN113119551B - Composite fiber membrane and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of textile fiber membranes. The invention provides a composite fiber membrane, which has a three-layer structure comprising a hydrophobic layer, a hydrophilic layer and a transfer layer, wherein each layer uses different solutes and solvents, a mixed solution is spun into a membrane in an electrostatic spinning mode, then the three layers of fiber membranes are combined together through the action of electrostatic force, and finally the solutes in the hydrophilic layer are crosslinked in an ultraviolet irradiation mode to obtain the composite fiber membrane. The composite fiber membrane provided by the application has outstanding separation efficiency in mixtures such as oil-water mixtures or oil-in-water emulsions, and the like, and is convenient for recovering substances.

Description

Composite fiber membrane and preparation method and application thereof

Technical Field

The invention relates to the technical field of textile fiber membranes, in particular to a composite fiber membrane and a preparation method and application thereof.

Background

With the progress of industrial production, water becomes an essential resource in development, and particularly in the fields of resource exploration and the like, the water resource plays multiple roles. When oil and gas exploitation is carried out, a large amount of water is often needed to cool the drill bit, and in the process of continuously going deep into the geology, the water used for cooling can wrap part of energy to return to the ground. Because of the uncertainty of oil and gas exploitation, complete equipment cannot be matched at the beginning of exploitation, and cooling water mixed with substances such as petroleum and the like is directly discharged into the natural environment without being treated in time, thereby causing certain influence on the ecological environment. The best method is to separate oil from water before discharging, but the separation efficiency is low, and most resources such as petroleum and the like are not ready for recovery.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a composite fiber membrane and a preparation method and application thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a composite fiber membrane, which comprises a hydrophobic layer, a hydrophilic layer and a transfer layer;

the hydrophobic layer is made from a raw material comprising the following components: the mass ratio of the solute to the solvent is 1: 9-11;

the transfer layer is made from a raw material comprising the following components: the solute a, the solute b and the solvent, wherein the mass ratio of the solute a to the solute b is 1: 9-11, and the mass ratio of the mass sum of the solute a and the solute b to the solvent is 1: 8.5-11.5;

the hydrophilic layer is made from raw materials comprising the following components: the solute I, the solute II and the solvent, wherein the mass ratio of the solute I to the solute II is 1: 9-11, and the mass ratio of the mass sum of the solute I and the solute II to the solvent is 1: 8.5-11.5.

Preferably, the solvent of the hydrophobic layer is acetone and dimethylformamide, the mass of the acetone is 20-40% of the mass of the solvent, and the solute of the hydrophobic layer is polystyrene or polytetrafluoroethylene;

in the transfer layer, a solute a is polyvinyl alcohol or polyvinylpyrrolidone, a solute b is polyacrylonitrile, polymethyl methacrylate, polyurethane or cellulose, and a solvent in the transfer layer is dimethylformamide;

solute I in the hydrophilic layer is methacrylic acyl ethyl sulfobetaine or 3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate, solute II is polyacrylonitrile, polymethyl methacrylate, polyurethane or cellulose, solvent in the hydrophilic layer is dimethylformamide and hexafluoroisopropanol, and the mass ratio of the hexafluoroisopropanol to the dimethylformamide is 1: 8-10.

Preferably, the composite fiber membrane sequentially comprises a hydrophilic layer, a hydrophobic layer and a transfer layer from top to bottom, or the hydrophilic layer, the transfer layer and the hydrophobic layer, or the transfer layer, the hydrophobic layer and the hydrophilic layer, or the hydrophobic layer, the transfer layer and the hydrophilic layer.

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

(1) Spinning the independently prepared hydrophobic layer solution, hydrophilic layer solution and transfer layer solution to obtain a fiber membrane;

(2) And carrying out crosslinking reaction on the fiber membrane and the hydrogel solution to obtain the composite fiber membrane.

Preferably, the hydrophobic layer solution, the hydrophilic layer solution and the transfer layer solution in the step (1) are obtained by independently stirring and ultrasonic processing;

the stirring time is 20-28 h, the stirring temperature is 18-60 ℃, and the stirring speed is 350-450 rpm;

the ultrasonic time is 0.3-0.7 h, the ultrasonic temperature is 18-60 ℃, and the ultrasonic frequency is 40-50 kHz.

Preferably, the inner diameter of the needle head for spinning in the step (1) is 0.3-0.5 mm, and the outer diameter of the needle head for spinning is 0.6-0.8 mm;

the spinning voltage is 12-18 KV, the spinning bolus velocity is 0.4-1.5 mL/h, the spinning time is 5-60 min, the distance between the spinning needle and the receiving roller is 15-20 cm, and the rotating speed of the receiving roller is 30-50 rpm;

the translation speed of the needle of the spinning is 280-320 mm/min, and the translation stroke of the spinning is 480-520 mm.

Preferably, the solvent of the hydrogel solution in the step (2) is sodium chloride aqueous solution, and the concentration of the sodium chloride aqueous solution is 0.5-1.5 mol/L;

the solute of the hydrogel solution comprises a cross-linking agent, an initiator and a solute I;

the cross-linking agent is methylene bisacrylamide, the mass ratio of the cross-linking agent to the solute I is 1: 90-110, and the mass concentration of the cross-linking agent to the solute I in the hydrogel solution is 5-15%;

the initiator is 2-hydroxy-2-methyl-1-phenyl-1-acetone, and the mass concentration of the initiator in the hydrosol solution is 1-5%.

Preferably, the wavelength of the ultraviolet light for the crosslinking reaction in the step (2) is 350 to 380nm, and the time for the crosslinking reaction is 10 to 30min.

The invention also provides application of the composite fiber membrane in oil-water separation.

Preferably, the oil-water is an oil-water mixture or an oil-in-water emulsion;

the diameter of the oil-in-water emulsion is 100-500 nm, and the oil is gasoline, kerosene, diesel oil, engine oil, n-hexane, cyclohexane, petroleum ether, dichlorotoluene, toluene, xylene, isooctane, carbon tetrachloride or chloroform.

The invention provides a composite fiber membrane, which has a three-layer structure comprising a hydrophobic layer, a hydrophilic layer and a transfer layer, wherein each layer uses different solutes and solvents, a mixed solution is spun into a membrane in an electrostatic spinning mode, then the three layers of fiber membranes are combined together through the action of electrostatic force, and finally the solutes in the hydrophilic layer are crosslinked in an ultraviolet irradiation mode to obtain the composite fiber membrane. The composite fiber membrane provided by the application has outstanding separation efficiency in oil-water mixture or oil-in-water emulsion and other mixtures, and is convenient for recovering substances.

Drawings

FIG. 1 is an SEM photograph of a composite fiber membrane of example 1, in which (A) is a sectional view; (B) a hydrophilic layer; (C) a hydrophobic layer; (D) a transfer layer (intermediate layer);

FIG. 2 is an oil sump test of the composite fiber membrane of example 1;

FIG. 3 is an underwater oil collection experiment of the composite fiber film of example 1;

FIG. 4 shows an oil-water separation experiment of the composite fiber membrane of example 1, in which (A) water is passed; (B) oiling; water is blue (copper nitrate staining), oil is red (oil red O staining);

FIG. 5 is an oil-in-water emulsion separation experiment of the composite fiber membrane of example 1, with the oil stained red (oil red O stain).

Detailed Description

The invention provides a composite fiber membrane, which comprises a hydrophobic layer, a hydrophilic layer and a transfer layer.

In the present invention, the hydrophobic layer is made of a raw material comprising: the mass ratio of the solute to the solvent is 1: 9-11, preferably 1: 9.5-10.5, and more preferably 1: 9.8-10.2.

In the present invention, the transfer layer is made of a raw material comprising: the solute a, the solute b and the solvent, wherein the mass ratio of the solute a to the solute b is 1: 9-11, preferably 1: 9.3-10.7, and more preferably 1: 9.6-10.4; the mass ratio of the mass sum of the solute a and the solute b to the solvent is 1: 8.5-11.5, preferably 1: 9-11, and more preferably 1: 9.5-10.5.

In the present invention, the hydrophilic layer is made of a raw material comprising: solute I, solute II and solvent, wherein the mass ratio of the solute I to the solute II is 1: 9-11, preferably 1: 9.4-10.6, and more preferably 1: 9.8-10.2; the mass ratio of the mass sum of the solute I and the solute II to the solvent is 1: 8.5-11.5, preferably 1: 9-11, and more preferably 1: 9.5-10.5.

In the present invention, the solvent of the hydrophobic layer is preferably acetone and dimethylformamide, and the mass of the acetone is preferably 20 to 40%, more preferably 24 to 36%, and even more preferably 28 to 32% of the mass of the solvent; the solute of the hydrophobic layer is preferably polystyrene or polytetrafluoroethylene.

In the present invention, the solute a in the transfer layer is preferably polyvinyl alcohol or polyvinylpyrrolidone, the solute b is preferably polyacrylonitrile, polymethyl methacrylate, polyurethane or cellulose, and the solvent in the transfer layer is preferably dimethylformamide.

In the invention, solute I in the hydrophilic layer is preferably methacryloyl ethyl sulfobetaine or 3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate, solute II is preferably polyacrylonitrile, polymethyl methacrylate, polyurethane or cellulose, solvent in the hydrophilic layer is preferably dimethylformamide and hexafluoroisopropanol, and the mass ratio of the hexafluoroisopropanol and the dimethylformamide is preferably 1: 8-10, more preferably 1: 8.5-9.5, and even more preferably 1: 8.8-9.2.

In the invention, the composite fiber membrane is preferably a hydrophilic layer, a hydrophobic layer and a transfer layer from top to bottom, or is preferably a hydrophilic layer, a transfer layer and a hydrophobic layer, or is preferably a transfer layer, a hydrophobic layer and a hydrophilic layer, or is preferably a hydrophobic layer, a transfer layer and a hydrophilic layer.

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

(1) Spinning the hydrophobic layer solution, the hydrophilic layer solution and the transfer layer solution which are independently prepared to obtain a fiber membrane;

(2) And carrying out crosslinking reaction on the fiber membrane and the hydrogel solution to obtain the composite fiber membrane.

In the present invention, the hydrophobic layer solution, the hydrophilic layer solution and the transfer layer solution in the step (1) are preferably obtained by independently stirring and ultrasonic processing.

In the present invention, the stirring time is preferably 20 to 28 hours, more preferably 22 to 26 hours, and still more preferably 23 to 25 hours; the stirring temperature is preferably 18-60 ℃, more preferably 28-50 ℃, and even more preferably 38-40 ℃; the rotation speed of the stirring is preferably 350 to 450rpm, more preferably 360 to 440rpm, and still more preferably 380 to 420rpm.

In the invention, the time of the ultrasonic treatment is preferably 0.3 to 0.7h, more preferably 0.4 to 0.6h, and even more preferably 0.45 to 0.55h; the temperature of the ultrasonic wave is preferably 18-60 ℃, more preferably 28-50 ℃, and even more preferably 38-40 ℃; the frequency of the ultrasonic wave is preferably 40 to 50kHz, more preferably 42 to 48kHz, and still more preferably 44 to 46kHz.

In the present invention, the inner diameter of the needle for spinning in the step (1) is preferably 0.3 to 0.5mm, more preferably 0.35 to 0.45mm; the outer diameter of the needle of the spinning is preferably 0.6 to 0.8mm, and more preferably 0.65 to 0.75mm.

In the present invention, the spinning voltage is preferably 12 to 18KV, more preferably 13 to 17KV, and still more preferably 14 to 16KV; the spinning bolus injection speed is preferably 0.4-1.5 mL/h, more preferably 0.6-1.3 mL/h, and even more preferably 0.8-1.1 mL/h; the spinning time is preferably 5 to 60min, more preferably 15 to 50min, and even more preferably 25 to 40min; the distance between the needle head of the spinning and the receiving roller is preferably 15-20 cm, more preferably 16-19 cm, and even more preferably 17-18 cm; the rotation speed of the receiving drum is preferably 30 to 50rpm, more preferably 33 to 47rpm, and still more preferably 37 to 43rpm.

In the invention, the translation speed of the needle head of the spinning is preferably 280-320 mm/min, more preferably 290-310 mm/min, and even more preferably 295-305 mm/min; the translation stroke of the spinning is preferably 480 to 520mm, more preferably 490 to 510mm, and still more preferably 495 to 505mm.

According to the invention, raw materials are prepared into a hydrophobic layer solution, a hydrophilic layer solution and a transfer layer solution through stirring and ultrasound, electrostatic spinning is sequentially carried out according to a specific sequence, after a first layer structure is spun, a second layer structure is spun through a reloading solution, after the second layer structure is spun, a third layer structure is spun through the reloading solution, and after all spinning is finished, the three layers are combined together through the action of electrostatic force to obtain the fiber membrane.

In the present invention, the solvent of the hydrogel solution in the step (2) is preferably an aqueous sodium chloride solution, and the concentration of the aqueous sodium chloride solution is preferably 0.5 to 1.5mol/L, more preferably 0.6 to 1.4mol/L, and still more preferably 0.9 to 1.1mol/L.

In the present invention, the solute of the hydrogel solution preferably comprises a crosslinking agent, an initiator, and solute I; the mass ratio of the solute I in the hydrogel solution to the solute I in the hydrophilic layer is preferably 0.8-1.2: 0.8-1.2, more preferably 0.9-1.1: 0.9-1.1, and even more preferably 0.95-1.05: 0.95-1.05. The solute I in the hydrogel solution and the solute I in the hydrophilic layer are the same in kind.

In the invention, the cross-linking agent is preferably methylene bisacrylamide, and the mass ratio of the cross-linking agent to the solute I is preferably 1: 90-110, more preferably 1: 92-108, and even more preferably 1: 98-102; the mass and mass concentration of the crosslinking agent and solute I in the hydrogel solution are preferably 5 to 15%, more preferably 6 to 14%, and still more preferably 9 to 11%.

In the present invention, the initiator is preferably 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the mass concentration of the initiator in the aqueous sol solution is preferably 1 to 5%, more preferably 2 to 4%, and still more preferably 2.5 to 3.5%.

In the invention, the wavelength of the ultraviolet light for the crosslinking reaction in the step (2) is preferably 350 to 380nm, more preferably 360 to 370nm, and even more preferably 363 to 367nm; the time for the crosslinking reaction is preferably 10 to 30min, more preferably 14 to 26min, and still more preferably 18 to 22min.

In the invention, the hydrogel solution is dripped on the hydrophilic layer, and the crosslinking reaction is carried out under the action of ultraviolet light.

In the present invention, after the crosslinking reaction is completed, washing and drying are preferably performed, the reagent for washing is preferably water, the number of times of washing is preferably 3 to 6 times, more preferably 4 to 5 times, and the temperature for drying is preferably 30 to 50 ℃, more preferably 35 to 45 ℃, and more preferably 38 to 42 ℃.

The invention also provides application of the composite fiber membrane in oil-water separation.

In the present invention, the oil-water is preferably an oil-water mixture or an oil-in-water emulsion.

In the present invention, the diameter of the oil-in-water emulsion is preferably 100 to 500nm, more preferably 200 to 400nm, and still more preferably 250 to 350nm; the oil is preferably gasoline, kerosene, diesel oil, engine oil, n-hexane, cyclohexane, petroleum ether, dichlorotoluene, toluene, xylene, isooctane, carbon tetrachloride or chloroform.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Preparing a hydrophobic layer raw material: 100g of polystyrene, 300g of acetone and 700g of dimethylformamide;

preparing a transfer layer raw material: 10g of polyvinyl alcohol, 100g of polyacrylonitrile and 1100g of dimethylformamide;

preparing a hydrophilic layer raw material: 20g of methyl acryloyl ethyl sulfobetaine, 200g of polyacrylonitrile, 200g of hexafluoroisopropanol and 2000g of dimethylformamide.

Stirring the above raw materials independently at 40 deg.C and 400rpm for 24h, performing ultrasonic treatment at 40 deg.C and 45kHz for 0.4h, and performing ultrasonic treatment to obtain hydrophobic layer solution, transfer layer solution and hydrophilic layer solution.

In this example, spinning was performed in the order of a hydrophilic layer, a transfer layer and a hydrophobic layer from top to bottom, and the hydrophobic layer was spun first.

Spinning a hydrophobic layer: the inner diameter of the needle is 0.4mm, the outer diameter of the needle is 0.7mm, the distance between the needle and the receiving roller is 16cm, the rotating speed of the receiving roller is 30rpm, the translation speed of the spinning needle is 290mm/min, and the translation stroke of spinning is 510mm;

the voltage during spinning is 14KV, the injection speed during spinning is 0.7mL/h, and the spinning time is 40min. And after spinning of the hydrophobic layer is finished, reloading the transfer layer solution and spinning the transfer layer.

Weaving a transfer layer: the inner diameter of the needle is 0.4mm, the outer diameter of the needle is 0.7mm, the distance between the needle and the receiving roller is 18cm, the rotating speed of the receiving roller is 40rpm, the translation speed of the spinning needle is 300mm/min, and the translation stroke of spinning is 500mm;

the voltage during spinning is 16KV, the injection speed during spinning is 0.8mL/h, and the spinning time is 30min. And after the spinning of the transfer layer is finished, replacing the hydrophilic layer solution and spinning the hydrophilic layer.

Weaving a hydrophilic layer: the inner diameter of the needle is 0.4mm, the outer diameter of the needle is 0.7mm, the distance between the needle and the receiving roller is 18cm, the rotating speed of the receiving roller is 50rpm, the translation speed of the spinning needle is 310mm/min, and the translation stroke of spinning is 490mm;

the voltage during spinning is 18KV, the injection speed during spinning is 1.2mL/h, and the spinning time is 35min. And (5) after the hydrophilic layer finishes spinning, obtaining the fiber membrane.

Preparing a hydrogel solution: the concentration of the sodium chloride aqueous solution was 1mol/L, the concentration of methacryloylethyl sulfobetaine was 20g, the concentration of methylenebisacrylamide was 0.2g, the mass sum of methylenebisacrylamide and methacryloylethyl sulfobetaine in the hydrogel solution was 10%, and the mass concentration of 2-hydroxy-2-methyl-1-phenyl-1-propanone in the hydrogel solution was 3%.

And dropwise adding the prepared hydrogel solution on the surface of the hydrophilic layer on the fiber membrane, performing crosslinking for 20min under ultraviolet light of 360nm after dropwise adding is completed, washing for 5 times by using deionized water after crosslinking is completed, and drying at 40 ℃ to obtain the composite fiber membrane.

The composite fiber film prepared in this example was observed under an electron microscope, and the result is shown in fig. 1.

The composite fiber membrane prepared in this example was subjected to an oil-water collecting test, and the results are shown in fig. 2.

The composite fiber film prepared in this example was subjected to an underwater oil collecting experiment, and the results are shown in fig. 3.

The composite fiber membrane prepared in this example was subjected to an oil-water separation experiment, and the results are shown in fig. 4.

The composite fiber membrane prepared in this example was subjected to an oil-in-water emulsion separation experiment, and the results are shown in fig. 5.

The composite fiber membrane prepared by the embodiment has the separation efficiency of 98% on water and petroleum ether.

Example 2

Preparing a hydrophobic layer raw material: 200g of polytetrafluoroethylene, 800g of acetone and 1200g of dimethylformamide;

preparing a transfer layer raw material: 20g of polyvinylpyrrolidone, 180g of polymethyl methacrylate and 2000g of dimethylformamide;

preparing a hydrophilic layer raw material: 15g of 3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate, 150g of polyvinyl chloride, 181.5g of hexafluoroisopropanol and 1633.5g of dimethylformamide.

Independently stirring the raw materials at 50 ℃ and 430rprn for 20h, performing ultrasonic treatment at 30 ℃ and 44kHz for 0.5h after stirring is finished, and obtaining a hydrophobic layer solution, a transfer layer solution and a hydrophilic layer solution after ultrasonic treatment is finished.

This example was spun in the order of transfer layer, hydrophobic layer and hydrophilic layer from top to bottom, the hydrophilic layer being spun first.

Weaving a hydrophilic layer: the inner diameter of the needle head is 0.5mm, the outer diameter of the needle head is 0.8mm, the distance between the needle head and the receiving roller is 18cm, the rotating speed of the receiving roller is 45rpm, the translation speed of the spinning needle head is 310mm/min, and the translation stroke of spinning is 490mm;

the voltage during spinning is 16KV, the injection speed during spinning is 1.3mL/h, and the spinning time is 35min. And after the hydrophilic layer spinning is finished, replacing the hydrophobic layer solution, and spinning the hydrophobic layer.

Spinning a hydrophobic layer: the inner diameter of the needle is 0.3mm, the outer diameter of the needle is 0.7mm, the distance between the needle and the receiving roller is 19cm, the rotating speed of the receiving roller is 30rpm, the translation speed of the spinning needle is 290mm/min, and the translation stroke of spinning is 490mm;

the voltage during spinning is 14KV, the injection speed during spinning is 1mL/h, and the spinning time is 25min. And after spinning of the hydrophobic layer is finished, reloading the transfer layer solution and spinning the transfer layer.

Weaving a transfer layer: the inner diameter of the needle is 0.5mm, the outer diameter of the needle is 0.6mm, the distance between the needle and the receiving roller is 20cm, the rotating speed of the receiving roller is 45rpm, the translation speed of the spinning needle is 320mm/min, and the translation stroke of spinning is 480mm;

the voltage during spinning is 15KV, the injection speed during spinning is 1.2mL/h, and the spinning time is 15min. And after the spinning of the transfer layer is finished, obtaining the fiber membrane.

Preparing a hydrogel solution: the concentration of the aqueous sodium chloride solution was 1.3mol/L, the mass sum of 3- [ [2- (methacryloyloxy) ethyl ] dimethylammonium ] propionate ester was 15g, the methylenebisacrylamide was 0.15g, the mass sum of methylenebisacrylamide and 3- [ [2- (methacryloyloxy) ethyl ] dimethylammonium ] propionate ester was 15%, and the mass concentration of 2-hydroxy-2-methyl-1-phenyl-1-propanone in the hydrogel solution was 2%.

And (3) dropwise adding the prepared hydrogel solution on the surface of the hydrophilic layer on the fiber membrane, crosslinking for 30min under 380nm ultraviolet light after dropwise adding is finished, washing for 5 times by using deionized water after crosslinking is finished, and drying at 50 ℃ to obtain the composite fiber membrane.

The composite fiber membrane prepared by the embodiment has the separation efficiency of 96% on water and diesel oil.

Example 3

Preparing a hydrophobic layer raw material: 50g of polystyrene, 110g of acetone and 440g of dimethylformamide;

preparing a transfer layer raw material: 5g of polyvinyl alcohol, 45g of cellulose and 450g of dimethylformamide;

preparing a hydrophilic layer raw material: 10g of methyl acryloyl ethyl sulfobetaine, 110g of polyurethane, 108g of hexafluoroisopropanol and 972g of dimethylformamide.

Independently stirring the raw materials at 50 ℃ and 390rpm for 23h, performing ultrasonic treatment at 60 ℃ and 48kHz for 0.7h after stirring is finished, and obtaining a hydrophobic layer solution, a transfer layer solution and a hydrophilic layer solution after ultrasonic treatment is finished.

This example was spun in the order hydrophilic, hydrophobic and transfer layers from top to bottom, the transfer layer being spun first.

Weaving a transfer layer: the inner diameter of the needle is 0.3mm, the outer diameter of the needle is 0.8mm, the distance between the needle and the receiving roller is 17cm, the rotating speed of the receiving roller is 35rpm, the translation speed of the spinning needle is 320mm/min, and the translation stroke of spinning is 490mm;

the voltage during spinning is 12KV, the injection speed during spinning is 0.8mL/h, and the spinning time is 30min. And after the spinning of the transfer layer is finished, replacing the hydrophobic layer solution, and spinning the hydrophobic layer.

Spinning a hydrophobic layer: the inner diameter of the needle is 0.5mm, the outer diameter of the needle is 0.7mm, the distance between the needle and the receiving roller is 20cm, the rotating speed of the receiving roller is 50rpm, the translation speed of the spinning needle is 290mm/min, and the translation stroke of spinning is 510mm;

the voltage during spinning is 18KV, the injection speed during spinning is 0.9mL/h, and the spinning time is 50min. And after spinning of the hydrophobic layer is finished, replacing the hydrophilic layer solution and spinning the hydrophilic layer.

Weaving a hydrophilic layer: the inner diameter of the needle is 0.3mm, the outer diameter of the needle is 0.6mm, the distance between the needle and the receiving roller is 16cm, the rotating speed of the receiving roller is 35rpm, the translation speed of the spinning needle is 300mm/min, and the translation stroke of spinning is 500mm;

the voltage during spinning is 16KV, the injection speed during spinning is 1.1mL/h, and the spinning time is 40min. And (5) after the hydrophilic layer finishes spinning, obtaining the fiber membrane.

Preparing a hydrogel solution: the concentration of the sodium chloride aqueous solution was 0.8mol/L, 10g of methacryloyl ethyl sulfobetaine, 0.1g of methylene bisacrylamide, the mass sum of methylene bisacrylamide and methacryloyl ethyl sulfobetaine in the hydrogel solution was 12%, and the mass concentration of 2-hydroxy-2-methyl-1-phenyl-1-propanone in the hydrogel solution was 5%.

And dropwise adding the prepared hydrogel solution on the surface of the hydrophilic layer on the fiber membrane, performing crosslinking for 15min under 350nm ultraviolet light after dropwise adding is finished, washing for 5 times by using deionized water after crosslinking is finished, and drying at 30 ℃ to obtain the composite fiber membrane.

The composite fiber membrane prepared in the embodiment has the separation efficiency of 97% on a mixture of water and gasoline.

According to the embodiment, the composite fiber membrane provided by the invention has the structures of the hydrophobic layer, the transfer layer and the hydrophilic layer, the three layers of structures are connected together through the acting force of electrostatic force, the composite fiber membrane provided by the invention has very high separation efficiency on oil-in-water emulsion and oil-water mixture, and the separation efficiency of the oil-water mixture reaches 98% to the maximum; the composite fiber film provided by the invention has particularly outstanding underwater oil collection or underwater water collection performance, and is a composite fiber film with excellent comprehensive performance.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (8)

1. A composite fibrous membrane comprising a hydrophobic layer, a hydrophilic layer, and a transfer layer;

the hydrophobic layer is made from a raw material comprising the following components: the mass ratio of the solute to the solvent is 1: 9-11;

the transfer layer is made from a raw material comprising the following components: the solute a, the solute b and the solvent, wherein the mass ratio of the solute a to the solute b is 1: 9-11, and the mass ratio of the mass sum of the solute a and the solute b to the solvent is 1: 8.5-11.5;

the hydrophilic layer is made from raw materials comprising the following components: the solute I, the solute II and the solvent, wherein the mass ratio of the solute I to the solute II is 1: 9-11, and the mass ratio of the mass sum of the solute I and the solute II to the solvent is 1: 8.5-11.5;

the solvent of the hydrophobic layer is acetone and dimethylformamide, the mass of the acetone is 20-40% of that of the solvent, and the solute of the hydrophobic layer is polystyrene or polytetrafluoroethylene;

in the transfer layer, a solute a is polyvinyl alcohol or polyvinylpyrrolidone, a solute b is polyacrylonitrile, polymethyl methacrylate, polyurethane or cellulose, and a solvent in the transfer layer is dimethylformamide;

solute I in the hydrophilic layer is methacrylic acyl ethyl sulfobetaine or 3- [ [2- (methacryloyloxy) ethyl ] dimethyl ammonium ] propionate, solute II is polyacrylonitrile, polymethyl methacrylate, polyurethane or cellulose, solvent in the hydrophilic layer is dimethylformamide and hexafluoroisopropanol, and the mass ratio of the hexafluoroisopropanol to the dimethylformamide is 1: 8-10;

a method of making a composite fiber membrane comprising the steps of:

(1) Spinning the hydrophobic layer solution, the hydrophilic layer solution and the transfer layer solution which are independently prepared to obtain a fiber membrane;

(2) Carrying out cross-linking reaction on the fiber membrane and the hydrogel solution to obtain the composite fiber membrane;

the wavelength of the ultraviolet light of the crosslinking reaction in the step (2) is 350-380 nm, and the time of the crosslinking reaction is 10-30 min.

2. The composite fiber membrane of claim 1, wherein the composite fiber membrane comprises, in order from top to bottom, a hydrophilic layer, a hydrophobic layer, and a transfer layer, or a hydrophilic layer, a transfer layer, and a hydrophobic layer, or a transfer layer, a hydrophobic layer, and a hydrophilic layer, or a hydrophobic layer, a transfer layer, and a hydrophilic layer.

3. The method for preparing the composite fiber membrane according to any one of claims 1 to 2, comprising the steps of:

(1) Spinning the hydrophobic layer solution, the hydrophilic layer solution and the transfer layer solution which are independently prepared to obtain a fiber membrane;

(2) And carrying out crosslinking reaction on the fiber membrane and the hydrogel solution to obtain the composite fiber membrane.

4. The method according to claim 3, wherein the hydrophobic layer solution, the hydrophilic layer solution and the transfer layer solution in the step (1) are obtained by stirring and ultrasonic processing independently;

the stirring time is 20-28 h, the stirring temperature is 18-60 ℃, and the stirring speed is 350-450 rpm;

the ultrasonic time is 0.3-0.7 h, the ultrasonic temperature is 18-60 ℃, and the ultrasonic frequency is 40-50 kHz.

5. The method of claim 3 or 4, wherein the inner diameter of the spinning needle in the step (1) is 0.3 to 0.5mm, and the outer diameter of the spinning needle is 0.6 to 0.8mm;

the spinning voltage is 12-18 KV, the spinning bolus injection speed is 0.4-1.5 mL/h, the spinning time is 5-60 min, the distance between the spinning needle and the receiving roller is 15-20 cm, and the rotating speed of the receiving roller is 30-50 rpm;

the translation speed of the needle of the spinning is 280-320 mm/min, and the translation stroke of the spinning is 480-520 mm.

6. The method according to claim 5, wherein the solvent of the hydrogel solution in the step (2) is an aqueous sodium chloride solution having a concentration of 0.5 to 1.5mol/L;

the solute of the hydrogel solution comprises a cross-linking agent, an initiator and a solute I;

the cross-linking agent is methylene bisacrylamide, the mass ratio of the cross-linking agent to the solute I is 1: 90-110, and the mass concentration of the cross-linking agent to the solute I in the hydrogel solution is 5-15%;

the initiator is 2-hydroxy-2-methyl-1-phenyl-1-acetone, and the mass concentration of the initiator in the hydrosol solution is 1-5%.

7. Use of the composite fiber membrane according to any one of claims 1 to 2 for oil-water separation.

8. The use of claim 7, wherein the oil-water is an oil-water mixture or an oil-in-water emulsion;

the diameter of the oil-in-water emulsion is 100-500 nm, and the oil is gasoline, kerosene, diesel oil, engine oil, n-hexane, cyclohexane, petroleum ether, dichlorotoluene, toluene, xylene, isooctane, carbon tetrachloride or chloroform.

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