Composite nanofiber membrane and application thereof

Abstract

The invention discloses a composite nanofiber membrane and application thereof, and belongs to the technical field of air filtration. The modular composite nanofiber protective tent is composed of a plurality of detachable magnetic square frames, each magnetic square frame is of a five-layer structure, the first layer (outermost layer) is printed cloth, the second layer is gauze, the third layer is an air filtering film (composite nanofiber film), the fourth layer is a magnetic strip, and the fifth layer is a mosquito net base. The preparation process is simple, and the used raw materials are less limited; the specific surface area and the porosity of the nanofiber membrane can be effectively increased, and the portability and the detachability are improved; an ordinary tent is endowed with the air filtering performance, and the problem that the air quality of a personal space is poor is solved; residues of organic toxic substances are avoided, and the method is more environment-friendly and safer.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of composite nanofiber membrane and its application, with good air filtration performance;Belong to air filtration technical field. BACKGROUND

[0002] With the rapid development of global economy, green and healthy is deeply rooted in people's minds, people's attention to the relationship between air quality and health is increasing day by day. People pay more and more attention to the air quality of daily life space, and they prefer to be in pure air. Air filtration membrane technology as a key technology for filtering air pollutants has been widely used in indoor air purification, mask filtration, industrial waste gas treatment and other fields;However, people in the past pay too much attention to the air quality of small space and neglect the air quality of life, such as the air quality of the room, resulting in poor quality of personal living space. Existing air filtration membrane technology includes: electrostatic nanofiber membrane technology, activated carbon filtration membrane technology, nanocomposite-based air filtration membrane technology, etc.

[0003] Chinese invention patent (authorized announcement number: CN103350544B, authorized announcement date: 2015-08-05) discloses a fabric with warm-keeping and heat-insulating functions and a preparation method thereof. The fabric includes a surface layer and a nanofiber warm-keeping layer. The nanofiber warm-keeping layer includes a base cloth and a nanofiber layer. The nanofiber warm-keeping layer is prepared by continuously depositing nanofibers containing nanometer aluminum powder on the base cloth by electrospinning. The fabric has the characteristics of light weight, heat insulation, warmth retention, and light volume. However, its disadvantages are that the fabric contains polymers, nanometer aluminum powder and other substances, and is not resistant to washing, with limited application environment.

[0004] Chinese invention patent (authorized announcement number: CN109107395A, authorized announcement date: 2019-01-01) discloses an anti-haze and anti-harmful gas air filter membrane, its preparation method and application. The air filter membrane includes a nanofiber membrane made of nanofibers with a two-dimensional or three-dimensional network structure. The nanofiber membrane can be a high molecular polymer nanofiber membrane made by electrospinning process, and can also be doped with organic or inorganic additives that can adsorb and absorb harmful gases such as VOCS, NOX, SOX and NH3 in the air and produce color response, and / or photocatalysts that can degrade these harmful gases by photocatalytic method. However, its disadvantages are that the manufacturing raw materials are expensive, and the preparation process is complex.

[0005] Therefore, a composite nanofiber membrane and its application, including a modular composite nanofiber protective tent and its preparation method, is provided. The preparation process is simple and the raw materials used are less restricted; the specific surface area and porosity of the nanofiber membrane can be effectively increased, and the portability and detachability can be improved; the air filtration performance that ordinary tents do not have is given, avoiding the problem of poor air quality in personal space; and the residue of organic toxic substances is avoided, which is more environmentally friendly and safe. These have become technical problems that need to be urgently solved in this technical field. Summary of the Invention

[0006] One of the purposes of the present invention is to provide a composite nanofiber membrane prepared by electrospinning technology, which has a simple preparation process and fewer restrictions on raw materials used; unlike traditional polymer nanofibers, by adding metal organic framework (MOF) material Prussian blue (PB), the specific surface area and porosity of the nanofiber membrane can be effectively increased, achieving better results.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] A composite nanofiber membrane is characterized by being composed of Prussian blue and polyacrylonitrile in a weight ratio of 3:13 to 7:13.

[0009] Preferably, the weight ratio of Prussian blue to polyacrylonitrile is 5:13.

[0010] Another object of the present invention is to provide a method for preparing the composite nanofiber membrane.

[0011] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0012] A method for preparing a composite nanofiber membrane, comprising the following steps:

[0013] (1) taking a certain amount of organic solvent and adding the polymer to obtain a uniform polymer solution;

[0014] (2) Weighing a certain amount of inorganic material and adding it to the uniform polymer solution, with the ratio of inorganic material to polymer being 3:13, 5:13, and 7:13, respectively, to obtain a spinning solution;

[0015] (3) electrospinning the spinning solution to obtain a composite nanofiber membrane;

[0016] (4) Drying the composite nanofiber membrane to remove the remaining organic solvent and obtain a composite nanofiber membrane.

[0017] Preferably, in step (1), the inorganic substance is Prussian blue (PB), and the polymer is polyacrylonitrile (PAN).

[0018] Preferably, in step (2), the organic solvent is N,N-dimethylformamide (DMF).

[0019] Preferably, in step (1), the inorganic substance and the polymer are dried in a vacuum oven at 80° C. to 100° C. for 2 h.

[0020] Preferably, in step (3), the process parameters of the electrospinning are: the electrospinning voltage is 18 to 20 kV, the temperature is 20° C. to 30° C., and the humidity is 30% to 40%.

[0021] Preferably, the receiving screen for electrospinning in step (3) is a non-woven fabric, and then the composite nanofiber membrane is dried in a vacuum oven at 60° C. to 80° C. for 2 h.

[0022] Another object of the present invention is to address existing technical problems and provide a modular composite nanofiber protective tent and a preparation method thereof. The preparation process is simple and the raw materials used are less restricted; it can effectively increase the specific surface area and porosity of the nanofiber membrane, improve portability and detachability; give ordinary tents air filtration performance that they do not have, avoiding the problem of poor air quality in personal space; avoid the residue of organic toxic substances, and be more environmentally friendly and safe.

[0023] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0024] A modular composite nanofiber protective tent, characterized in that the modular composite nanofiber protective tent is composed of multiple detachable magnetic frames, each magnetic frame includes: an overall five-layer structure, the first layer (outermost layer) is printed cloth, the second layer is gauze, the third layer is an air filter membrane (composite nanofiber membrane), the fourth layer is a magnetic strip, and the fifth layer is a mosquito net base.

[0025] Preferably, the air filter membrane has a thickness of 1 to 10 microns.

[0026] Preferably, the length of the magnetic frame is 20 to 35 cm and the width is 2 to 35 cm.

[0027] Preferably, the magnetic strip has a length of 20 to 130 cm and a width of 1 to 10 cm.

[0028] Preferably, the left side of the tent is a magnetic door curtain, and the length of the magnetic door curtain is 110 to 130 cm and the width is 35 to 50 cm.

[0029] The present invention also provides a method for preparing the modular composite nanofiber protective tent.

[0030] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0031] A method for preparing a modular composite nanofiber protective tent, comprising the following steps:

[0032] (1) Preparation of magnetic frame;

[0033] (2) Assembly of magnetic frames: Arrange 50 to 60 magnetic frames around and on the top;

[0034] (3) Installation of magnetic door curtain: Make a magnetic door curtain and install it on the left side of the tent;

[0035] (4) Overall assembly: all magnetic frames and magnetic door curtains (the magnetic door curtain is a larger magnetic frame) are connected by magnetic strips between the magnetic frames and between the magnetic frames and the magnetic door curtains, and assembled into a complete protective tent structure according to design requirements.

[0036] Preferably, step (1) is specifically as follows: each magnetic frame has a length of 20 to 35 cm and a width of 2 to 35 cm, and these frames are composed of five layers, namely: the first layer (outermost layer): printed cloth (1); the second layer: gauze (2); the third layer: composite nanofiber membrane (3); the fourth layer: magnetic strips (4); and the fifth layer: mosquito net base (5).

[0037] Preferably, in step (3), the length of the magnetic door curtain is 110 to 130 cm, and the width is 35 to 50 cm.

[0038] Preferably, in step (4), the magnetic strip has a length of 20 to 130 cm and a width of 1 to 10 cm.

[0039] Advantages of the present invention:

[0040] (1) The present invention uses electrospinning technology to prepare composite nanofiber membranes, which has a simple preparation process and fewer restrictions on raw materials. Unlike traditional polymer nanofibers, the addition of MOF material PB can effectively increase the specific surface area and porosity of the nanofiber membrane, achieving better results.

[0041] (2) The modular composite nanofiber protective tent provided by the present invention has improved portability and detachability due to the use of a magnetic modular structure;

[0042] (3) The composite nanofiber protective tent provided by the present invention, through the MOF-doped nanofiber air filtration membrane, is endowed with air filtration performance that ordinary tents do not have, thus avoiding the problem of poor air quality in personal space;

[0043] (4) The present invention subjects the polymer powder and the prepared composite nanofiber membrane to a certain vacuum drying process, thereby avoiding the residue of organic toxic substances and making the finished product more environmentally friendly and safe.

[0044] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the scope of protection of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic structural diagram of a modular composite nanofiber protective tent in Example 4 of the present invention;

[0046] Figure 2 This is a schematic structural diagram of the magnetic frame in the modular composite nanofiber protective tent in Example 4 of the present invention;

[0047] Figure 3 Schematic diagram of the structure of the electrospinning device in the preparation of the PB / PAN composite nanofiber membrane in Example 1 of the present invention;

[0048] Figure 4 The electron microscope image and composition of the PB / PAN composite nanofiber film in Example 1 of the present invention;

[0049] Figure 5-1 Filtration efficiency diagram of PB / PAN composite nanofiber membrane in Example 1 of the present invention;

[0050] Figure 5-2 This is the pressure drop diagram of the PB / PAN composite nanofiber membrane in Example 1 of the present invention. DETAILED DESCRIPTION

[0051] In the following examples, unless otherwise specified, the raw materials are all commercially available conventional raw materials, the equipment are all conventional equipment used in the art, and the methods used are all commonly used methods in the art.

[0052] In order to more clearly illustrate the advantages of the present invention, the embodiments and effects of the present invention are further described through specific examples. Obviously, the embodiments described here are not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art are within the scope of protection of the present invention.

[0053] The air filtration test in the following examples uses a TSI 3600 air filter, an aerosol particle diameter of 0.25 μm, and a gas flow rate of 32 liters / min.

[0054] Example 1

[0055] The preparation steps of PB / PAN composite nanofiber membrane are as follows:

[0056] In the first step, 10 mL of N,N-dimethylformamide (DMF) was measured and 1.295 g of polyacrylonitrile (PAN) was added to obtain a 12 wt% polyacrylonitrile (PAN) uniform solution; then, 0.299 g of Prussian blue (PB) was weighed and added to the polyacrylonitrile (PAN) uniform solution to obtain a spinning solution; then, the spinning solution was injected into the syringe of the electrospinning device, and the spinning solution was sprayed through the electrospinning device to form nano-scale fibers, and continuously accumulated on the roller to form a PB / PAN composite nanofiber membrane. The spinning temperature was 25 ° C, the humidity was 30%, the spinning voltage was 20 kV, the straight-line distance from the spinning needle to the receiver was 15 cm, the speed of the receiving roller was 80 r / min, and the propulsion speed of the spinning solution was 1 mL / h;

[0057] In the second step, the PB / PAN (Prussian blue / polyacrylonitrile) composite nanofiber membrane obtained by electrospinning was placed in a vacuum oven and dried at 80°C for 2 h;

[0058] In the third step, the dried PB / PAN composite nanofiber membrane was placed in an air filter and tested under the conditions of PM2.5 aerosol particles and an air flow rate of 32 liters / min. Its filtration efficiency reached 96.7%, the pressure drop was 170.1Pa, and the quality factor was 0.020. After the test, the sample was intact, indicating that it has broad application prospects in air filtration and other fields.

[0059] like Figure 3 As shown, it is a structural schematic diagram of the electrospinning device in the preparation of the PB / PAN composite nanofiber membrane in Example 1 of the present invention; the spinning solution is injected into the syringe of the electrospinning device, the liquid outlet of which is equipped with a metal needle, which is fixed on the perfusion propulsion device of the electrospinning equipment, and an electric field is formed by a high-voltage power supply to generate electrostatic polarization, so that a charge is formed on the surface of the droplet at the syringe needle. By continuously increasing the voltage, the electrostatic repulsive force on the surface of the droplet at the tip of the syringe can gradually overcome its own surface tension. Under the interaction of the two forces, the surface of the droplet gradually changes from the original rounded outer contour to form a Taylor cone, and finally breaks through the surface tension to generate a jet, which is continuously stretched into fibers in the process of reaching the receiving device (drum), and the surface solvent is rapidly evaporated due to the jet disturbance, the wet fiber gradually solidifies, and more and more fibers are collected on the drum, and finally a PB / PAN composite nanofiber membrane is prepared;

[0060] like Figure 4The following is a scanning electron microscope image and composition of the PB / PAN nanofiber film in Example 1 of the present invention; the microscopic morphology of the nanofiber membrane was observed using a scanning electron microscope (SEM), with the scanning voltage set to 5 kV, the scanning current set to 10 μA, and the magnification adjusted to an appropriate level. Combined with EDS analysis, the four elements and their mass fractions were obtained as follows: C 67.25%, N 12.17%, O 18.12%, and Zr 2.46%. Figure 4 The leftmost picture in the upper middle section is an electron microscope image.

[0061] Example 2

[0062] The preparation steps of PB / PAN composite nanofiber membrane are as follows:

[0063] In the first step, 10 mL of N,N-dimethylformamide (DMF) was measured and 1.295 g of polyacrylonitrile (PAN) was added to obtain a 12 wt% polyacrylonitrile (PAN) uniform solution; then, 0.498 g of Prussian blue (PB) was weighed and added to the polyacrylonitrile (PAN) uniform solution to obtain a spinning solution; then, the spinning solution was injected into the syringe of the electrospinning device, and the spinning solution was sprayed through the electrospinning device to form nano-scale fibers, which were continuously accumulated on the roller to form a PB / PAN composite nanofiber membrane. The spinning temperature was 25 ° C, the humidity was 30%, the spinning voltage was 20 kV, the straight-line distance from the spinning needle to the receiver was 15 cm, the speed of the receiving roller was 80 r / min, and the propulsion speed of the spinning solution was 1 mL / h;

[0064] In the second step, the PB / PAN composite nanofiber membrane obtained by electrospinning was placed in a vacuum oven and dried at 80 °C for 2 h;

[0065] In the third step, the dried PB / PAN composite nanofiber membrane was placed in an air filter and tested under the conditions of aerosol particles of PM2.5 and an air flow rate of 32 liters / min. Its filtration efficiency reached 99.8%, the pressure drop was 190.2Pa, and the quality factor was 0.033. After the test, the sample was intact, so it has broad application prospects in fields such as air filtration.

[0066] Example 3

[0067] The preparation steps of PB / PAN composite nanofiber membrane are as follows:

[0068] In the first step, 10 mL of N,N-dimethylformamide (DMF) was measured and 1.295 g of polyacrylonitrile (PAN) was added to obtain a 12 wt% polyacrylonitrile (PAN) uniform solution; then, 0.697 g of Prussian blue (PB) was weighed and added to the polyacrylonitrile (PAN) uniform solution to obtain a spinning solution; then, the spinning solution was injected into the syringe of the electrospinning device, and the spinning solution was sprayed through the electrospinning device to form nano-scale fibers, which were continuously accumulated on the roller to form a PB / PAN composite nanofiber membrane. The spinning temperature was 25 ° C, the humidity was 30%, the spinning voltage was 20 kV, the straight-line distance from the spinning needle to the receiver was 15 cm, the speed of the receiving roller was 80 r / min, and the propulsion speed of the spinning solution was 1 mL / h;

[0069] In the second step, the PB / PAN composite nanofiber membrane obtained by electrospinning was placed in a vacuum oven and dried at 80 °C for 2 h;

[0070] In the third step, the dried PB / PAN composite nanofiber membrane was placed in an air filter and tested under the conditions of aerosol particles of PM2.5 and an air flow rate of 32 liters / min. Its filtration efficiency reached 99.2%, the pressure drop was 199.7Pa, and the quality factor was 0.024. After the test, the sample was intact, so it has broad application prospects in fields such as air filtration.

[0071] Example 4

[0072] A modular composite nanofiber protective tent is prepared in the following steps:

[0073] Step 1: Prepare magnetic square frames, each of which has a length of 20 to 35 cm and a width of 2 to 35 cm. These square frames are composed of five layers, namely: the first layer (outermost layer): printed cloth (1); the second layer: gauze (2); the third layer: composite nanofiber membrane (3); the fourth layer: magnetic strips (4); the fifth layer: mosquito net base (5);

[0074] Step 2: Assemble the magnetic boxes, determine the correct position of the magnetic boxes, and arrange 50 to 60 magnetic boxes around and on the top;

[0075] Step 3: Install the magnetic door curtain. Make a magnetic door curtain with a length of 110 to 130 cm and a width of 35 to 50 cm. Install the magnetic door curtain on the left side of the tent.

[0076] Step 4: Assemble the whole structure, connect all the magnetic boxes and the magnetic door curtain. The magnetic door curtain is a larger magnetic box. The magnetic boxes and the magnetic boxes, as well as the magnetic box and the magnetic door curtain, are linked by magnetic strips. The fourth layer of each magnetic box is a circle of magnetic strips. The length of the magnetic strips is 20 to 130 cm and the width is 1 to 10 cm. When the two touch each other, they will be magnetically attracted together. Assemble into a complete protective tent structure according to the design requirements, ensure that the connection between each magnetic box is firm, and all layers of materials are installed correctly.

[0077] Step 5: Quality Inspection: Carry out quality inspection on the finished product to ensure that the five-layer structure of each magnetic frame is intact, check whether the magnetic door curtain functions normally, and whether the nanofiber membrane has the expected protective effect.

[0078] Through the above steps, a modular composite nanofiber protective tent with protective function can be prepared.

[0079] like Figure 1 As shown, it is a structural schematic diagram of the modular composite nanofiber protective tent in Example 5 of the present invention; in Example 5 of the present invention, the modular composite nanofiber protective tent is composed of 56 independent magnetic frames, and there are 50 to 60 magnetic frames on the surrounding and top mosquito net bases, and the length of the magnetic frame is 20 to 35 cm and the width is 2 to 35 cm; the left side is a magnetic door curtain with a length of 110 to 130 cm and a width of 35 to 50 cm; each magnetic frame has a five-layer structure, such as Figure 2 , which is a schematic structural diagram of the magnetic frame in the modular composite nanofiber protective tent in Example 5 of the present invention; the first layer (outermost layer) is a printed cloth (1), the second layer is a gauze (2), the third layer is a composite nanofiber membrane (3), the fourth layer is a magnetic strip (4), and the fifth layer is a mosquito net base (5);

[0080] On air filter membrane (composite nanofiber membrane) (randomly distributed pores with a size of 1nm to 100nm);

[0081] like Figure 5-1 As shown in FIG, the filtration efficiency diagram of the PB / PAN composite nanofiber membrane in Example 1 of the present invention; Figure 5-2 The figure shows the pressure drop diagram of the PB / PAN composite nanofiber membrane in Example 1 of the present invention. The PAN / PB nanofiber membrane obtained under different spinning conditions was tested using a TSI-3160 automatic air filter. The test conditions were: at room temperature and pressure, using a 10×10 cm 2 The loading test of composite nanofiber films of different sizes was carried out using a monodisperse aerosol with a particle size of 0.3 μm and a flow rate of 32 L / min.

[0082] like Figure 5-1The results show that the filtration effect of PAN / PB composite nanofibers is above 90%, and the filtration effect of PAN / PB-3 composite nanofiber membrane is 96.7%. With the increase of PB content, the filtration effect gradually increases. The filtration effect of PAN / PB-5 is 99.82%, and the filtration effect of PAN / PB-7 is 99.24%. However, the filtration effect of PAN / PB-5 and PAN / PB-7 is 99.82% and 99.24% respectively. Figure 5-2 The pressure drop curve in the graph generally shows an increasing trend. With the increase of PB content, the air filtration effect of the nanofiber composite film does not show an increasing state, although the difference is not large. Combined with the analysis of the electron microscope images, PB is not attached to the fiber surface as a single particle, and local agglomerates appear. This agglomerate may be due to a large number of PB particles wrapped with a large amount of unfilamented PAN solution, which not only fails to play the role of PB, but also blocks the pores of the film, resulting in the inability to capture aerosol particles. Since the fiber loses its integrity, the agglomerated blocks lead to poor connection and the mechanical properties of the fiber decrease. Therefore, based on the quality factor calculated by combining the filtration efficiency and pressure drop, the PAN / PB-5 film has the best performance.

[0083] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A composite nanofiber membrane, characterized in that: The invention is composed of Prussian blue and polyacrylonitrile, and the weight ratio thereof is 3:13 to 7:

13.

2. The composite nanofiber membrane according to claim 1, characterized in that: The weight ratio of the Prussian blue to the polyacrylonitrile is 5:

13.

3. A method for preparing the composite nanofiber membrane according to any one of claims 1 to 2, comprising the following steps: (1) taking a certain amount of organic solvent and adding the polymer to obtain a uniform polymer solution; (2) Weighing a certain amount of inorganic matter and adding it to the uniform polymer solution to obtain a spinning solution; (3) electrospinning the spinning solution to obtain a composite nanofiber membrane; (4) Drying the composite nanofiber membrane to remove the remaining organic solvent and obtain a composite nanofiber membrane.

4. The method for preparing the composite nanofiber membrane according to claim 1, wherein: In step (1), the inorganic substance is Prussian blue, the polymer is polyacrylonitrile, and the solvent is N,N-dimethylformamide.

5. The method for preparing the composite nanofiber membrane according to claim 1, characterized in that: In step (2), the ratios of the inorganic substance to the polymer are 3:13, 5:13, and 7:13, respectively.

6. The method for preparing the composite nanofiber membrane according to claim 1, characterized in that: In step (3), the process parameters of electrospinning are: the electrospinning voltage is 18-20 kV, the temperature is 20° C.-30° C., the humidity is 30%-40%, and the concentration of the spinning solution is 8%-15%.

7. The method for preparing the composite nanofiber membrane according to claim 1, characterized in that: In step (3), the receiving screen for electrospinning is a non-woven fabric, and then the composite nanofiber membrane is dried in a vacuum oven at 60° C. to 80° C. for 2 h.

8. Use of the composite nanofiber membrane according to any one of claims 1 to 2 for preparing a modular composite nanofiber protective tent.

9. The use of the composite nanofiber membrane according to claim 8, characterized in that: The modular composite nanofiber protective tent consists of multiple detachable magnetic frames, each of which includes: a five-layer structure, the first layer is printed cloth, the second layer is gauze, the third layer is composite nanofiber membrane, the fourth layer is magnetic strips, and the fifth layer is the mosquito net base.

10. The use of the composite nanofiber membrane according to claim 9, characterized in that: The thickness of the composite nanofiber membrane is 1 to 10 microns; the length of the magnetic frame is 20 to 35 cm, and the width is 2 to 35 cm; the length of the magnetic strip is 20 to 130 cm, and the width is 1 to 10 cm; the left side of the tent is a magnetic door curtain, and the length of the magnetic door curtain is 110 to 130 cm, and the width is 35 to 50 cm.

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