Preparation of super-amphiphilic coal-based fiber membrane and application of super-amphiphilic coal-based fiber membrane in air purification

Abstract

The invention belongs to the technical field of coal-based fiber membranes, and discloses preparation of a super-amphiphilic coal-based fiber membrane and application of the super-amphiphilic coal-based fiber membrane in air purification. The preparation method comprises the following steps: dissolving polyacrylonitrile and coal oxide in N, N-dimethylformamide to obtain a spinning solution A; polyacrylonitrile and candle ash nanoparticles are dissolved in N, N-dimethylformamide, and a spinning solution B is obtained; simultaneously performing electrostatic spinning on the spinning solution A and the spinning solution B through a conjugate electrostatic spinning device to obtain a fiber precursor; and then carrying out pre-oxidation. According to the method, submicron coal-based fibers and nanoscale candle ash nanoparticle modified polyacrylonitrile superfine fibers are electrospun at the same time in a synchronous opposite spraying mode, so that the super-amphiphilic coal-based fiber membrane is prepared, and the composition of the fiber membrane and the regulation and control of a pore channel structure are realized by adjusting the volumes of two spinning solutions.

Description

Technical Field

[0001] This invention relates to the field of coal-based fiber membrane technology, and in particular to the preparation of an ultra-amphiphilic coal-based fiber membrane and its application in air purification. Background Technology

[0002] Airborne particulate matter (PMs) pollution poses a serious threat to human health. Traditional separation / filtration materials, such as porous carbon, sponges, meltblown fibers, and glass fibers, have limited effectiveness in separating smoke particles due to their relatively large pore sizes. Compared to traditional fibers, electrospun fibers possess advantages such as a three-dimensional interconnected pore structure, high porosity, controllable structural composition, and ease of functional modification, making them highly advantageous for filtering smoke particles. However, real-world application environments are highly complex, and single-function and single-structure fiber membranes cannot meet practical application requirements. Therefore, constructing unique fiber structures and pore characteristics is essential for obtaining high-performance filter fiber membranes. Currently, many electrospun membranes are used as filter materials for efficient air purification.

[0003] Li et al. (Li YJ, Yuan D., Geng Q., et al. MOF-embedded bifunctional composite nanofiber membranes with a tunable hierarchical structure for high-efficiency PM(0.3) purification and oil / water separation[J]. ACS Applied Materials & Interfaces, 2021, 13(33): 39831-39843.) reported a layered composite nanomembrane (PES@ZIF8-PSA / PES) composed of ZIF-8@polyethersulfone fiber (ZIF-8@PES) and polysulfonamide / polyethersulfone fiber (PSA / PES), and applied it to high-efficiency oil-water separation and air filtration. Due to its superhydrophobicity, it exhibits good separation performance in the separation of oil-water mixtures and oil-water emulsions. In addition, due to the multi-component and layered structure of the fiber membrane, it is effective for the separation of fine smoke particles (especially PM). 0.3The filtration efficiency of ZIF-8 is as high as 99.98%, and its separation performance remains basically unchanged after 24 filtrations. Similarly, Geng et al. (Geng Q., Dong SJ, Li YJ, et al. High-performance photoinduced antimicrobial membrane toward efficient PM2.5-0.3 capture and oil-water separation[J]. Separation and Purification Technology, 2022, 284:120267-120280.) successfully embedded ZIF-8 into PVDF fibers by electrospinning, thereby obtaining a superhydrophobic composite fiber membrane with both filtration and separation properties. Chen et al. (Chen M., Cheng XH, Li JW, et al. Bifunctional polyimide / ZIF-8 composite nanofibrous membranes with controllable bilayer structure for bioprotective application and high-efficiency oil / water separation[J]. Journal of Environmental Chemical Engineering, 2023, 11(5): 110913-110924.) used vacuum sputtering technology to deposit ZnO seed crystals onto the surface (one side) of polyimide (PI), and then prepared a ZIF-8 / PI bilayer composite fiber membrane by hydrothermal method. The fiber membrane exhibits good superhydrophobicity, large porosity, and suitable pore size, resulting in oil-water separation efficiency and smoke particle removal rate both exceeding 99.6%. While the aforementioned fiber membrane demonstrates excellent separation performance in air purification, the structural stability of the fiber membrane has not been discussed. Furthermore, existing filtration membrane materials generally suffer from problems such as large air pressure drop, strong hydrophobicity, low filtration efficiency, and single-use capability, limiting the application range of fiber membranes. Furthermore, a major problem with commercially available mask filter materials is the difficulty in simultaneously achieving filtration efficiency, breathability, and heat dissipation: pursuing high filtration efficiency (especially against smoke particles) often requires the use of dense materials, which significantly increases breathing resistance and reduces heat dissipation; while prioritizing breathability and comfort often results in substandard filtration performance. Therefore, how to regulate the pore structure of fiber membranes to meet the filtration requirements of smoke particles and improve wearing comfort is of great significance for the commercial application of filter fiber membranes. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing an amphiphilic coal-based fiber membrane and its application in air purification, thereby solving the aforementioned problems of existing filter fiber membranes.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a superamphilic coal-based fiber membrane, comprising the following steps: Polyacrylonitrile and coal oxide were dissolved in N,N-dimethylformamide to obtain spinning solution A; Polyacrylonitrile and candle ash nanoparticles were dissolved in N,N-dimethylformamide to obtain spinning solution B; Spinning solution A and spinning solution B are placed in opposing micro-propellers, and electrospinning solution A and spinning solution B are simultaneously performed by a conjugate electrospinning device to obtain fiber filaments. The fiber precursor was pre-oxidized to obtain an ultra-amphiphilic coal-based fiber membrane.

[0006] Preferably, the ratio of polyacrylonitrile, coal oxide, and N,N-dimethylformamide in the spinning solution A is 1 g: 1~1.5 g: 10 mL.

[0007] Preferably, the ratio of polyacrylonitrile, candle ash nanoparticles, and N,N-dimethylformamide in the spinning solution B is 0.6 g: 0.1~0.5 g: 10 mL.

[0008] Preferably, the weight-average molecular weight of polyacrylonitrile in spinning solution A and spinning solution B is 150,000.

[0009] Preferably, the electrospinning conditions are: temperature 30~40 ℃, humidity 10~20%, receiving distance 15~20 cm, and voltage -3.5~+14 kV.

[0010] Preferably, the volume ratio of spinning solution A to spinning solution B is 1~2:1~4.

[0011] Preferably, the pre-oxidation temperature is 300~320 ℃; the pre-oxidation time is 1~3 h.

[0012] The present invention also provides a superamphilic coal-based fiber membrane prepared by the above preparation method.

[0013] The present invention also provides an application of an ultra-amphiphilic coal-based fiber membrane prepared by the above preparation method in air purification.

[0014] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses a simultaneous electrospinning method to simultaneously electrospin submicron-sized coal-based fibers and nano-sized candle ash nanoparticles (CSNPs) modified polyacrylonitrile (PAN) ultrafine fibers, thereby preparing an ultra-amphiphilic coal-based fiber membrane. By adjusting the volumes of the two spinning solutions, the composition and pore structure of the fiber membrane can be controlled. When the ratio of submicron-sized coal-based fibers to ultrafine fibers is 1:2, both sufficient exposure of coal-based fibers and a large amount of ultrafine fibers can be achieved. The dual-scale diameters form a hierarchical rough structure, which significantly reduces the pore size of the fiber membrane while ensuring high porosity. Compared with ultrafine fibers without added CSNPs, the ultrafine fibers induced by CSNPs have a smaller diameter, and the surface of the ultrafine fibers contains a hierarchical rough structure. The fiber membrane containing CSNPs exhibits superior wettability, anti-adhesion, tensile strength, and filtration performance.

[0015] (2) The super-amphiphilic coal-based fiber membrane of the present invention has a filtration efficiency of over 99% for smoke particles of different sizes, while the pressure drop is only 24 Pa. Its filtration performance is far superior to that of commercial masks, and it also shows good renewability. In addition, the filter mask made of the super-amphiphilic coal-based fiber membrane shows better breathability and radiative cooling compared with commercial medical masks and activated carbon masks, which can significantly improve wearing comfort. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0017] Figure 1 This is a flowchart illustrating the preparation process of a superamphilic coal-based fiber membrane according to the present invention. Figure 2 UFRCFM for Example 3 1:2 SEM images and fiber diameter statistics; where a is the SEM image and b is the fiber diameter statistics. Figure 3 SEM images and fiber diameter statistics of UFRCFM-C in Comparative Example 1 are shown; where a is the SEM image and b is the fiber diameter statistics. Figure 4 UFRCFM for Example 3 1:2 Wetting properties in air; where a is the superhydrophilicity diagram and b is the superoleophilicity diagram; Figure 5 UFRCFM for Example 3 1:2 The pore size and porosity of UFRCFM-C in Comparative Example 1; where a is the pore size and b is the porosity; Figure 6 UFRCFM for Example 3 1:2The stress-strain curves of UFRCFM-C in Comparative Example 1; Figure 7 This is a schematic diagram of the filtration device used to test the capture capacity of the superamphilic coal-based fiber membranes of Examples 1-5 and Comparative Example 1 for oily smoke particles. Figure 8 The graphs show the filtration performance of the superamphilic coal-based fiber membranes of Examples 1-5 and Comparative Example 1; where a represents the filtration performance of the superamphilic coal-based fiber membranes of Examples 1-5 at an airflow rate of 15 L / min. -1 The following is a filtration performance graph, where b represents UFRCFM. 1:2 Filtration performance graphs at different airflow velocities, where c represents UFRCFM. 1:2 The filtration performance graph is shown for 40 minutes. d represents the filtration performance of UFRCFM-C for 40 minutes. Figure 9 UFRCFM for Example 3 1:2 The filtration performance diagrams are as follows: a is the SEM image of the filter after circulation without cleaning, b is the SEM image of the filter after circulation with cleaning, and c is the filtration performance diagram of the filter after circulation with cleaning. Figure 10 The diagram shows the filtration performance of disposable medical masks and activated carbon masks. Figure 11 For example, the UFRCFM of Example 3 1:2 Infrared thermal images of the prepared filter masks, disposable medical masks, and activated carbon masks; where a is a disposable medical mask, b is an activated carbon mask, and c is a UFRCFM mask prepared in Example 3. 1:2 Prepared filter masks; Figure 12 UFRCFM for Example 3 1:2 A schematic diagram of smoke particle filtration. Detailed Implementation

[0018] This invention provides a method for preparing a superamphilic coal-based fiber membrane, the preparation flow chart of which is shown below. Figure 1 As shown, it includes the following steps: Polyacrylonitrile and coal oxide were dissolved in N,N-dimethylformamide to obtain spinning solution A; Polyacrylonitrile and candle ash nanoparticles were dissolved in N,N-dimethylformamide to obtain spinning solution B; Spinning solution A and spinning solution B are placed in opposing micro-propellers, and electrospinning solution A and spinning solution B are simultaneously performed by a conjugate electrospinning device to obtain fiber filaments. The fiber precursor was pre-oxidized to obtain an ultra-amphiphilic coal-based fiber membrane.

[0019] In this invention, the method for preparing the oxidized coal is as follows: raw coal (lignite) from Heishan, Xinjiang, is dried, crushed, and sieved (200 mesh), and then the raw coal is subjected to liquid-phase oxidation (mixed acid, V... 浓硫酸 V 浓硝酸 The mixture is 3:1, washed, dried, and ground to obtain oxidized coal.

[0020] In this invention, the method for preparing the candle ash nanoparticles is as follows: a clean crucible is placed about 3 cm above a lit candle. After a period of time, a layer of black particles attached to the bottom of the crucible is the candle ash nanoparticles. These particles are scraped off with a spatula and placed into a clean sample bottle for later use.

[0021] In this invention, the preferred ratio of polyacrylonitrile, coal oxide, and N,N-dimethylformamide in the spinning solution A is 1 g: 1~1.5 g: 10 mL, more preferably 1 g: 1~1.2 g: 10 mL, and even more preferably 1 g: 1 g: 10 mL.

[0022] In this invention, the preferred ratio of polyacrylonitrile, candle ash nanoparticles, and N,N-dimethylformamide in the spinning solution B is 0.6 g: 0.1~0.5 g: 10 mL, more preferably 0.6 g: 0.1~0.2 g: 10 mL, and even more preferably 0.6 g: 0.15 g: 10 mL.

[0023] In this invention, the weight-average molecular weight of polyacrylonitrile in spinning solution A and spinning solution B is preferably 150,000.

[0024] In this invention, the conjugate electrospinning device is derived from the ET-3S electrospinning machine of Yongkang Leyue Technology Development Co., Ltd.

[0025] In this invention, the conditions for electrospinning are as follows: the temperature is preferably 30~40 ℃, more preferably 32~38 ℃, and even more preferably 35 ℃; the humidity is preferably 10~20%, more preferably 12~17%, and even more preferably 15%; the receiving distance is preferably 15~20 cm, more preferably 16~19 cm, and even more preferably 18 cm; and the voltage is preferably -3.5~+14 kV, more preferably +2~+10 kV, and even more preferably +8 kV.

[0026] In this invention, the volume ratio of spinning solution A to spinning solution B is preferably 1~2:1~4, more preferably 2:1, 1:1, 1:2, 1:3 or 1:4, and even more preferably 1:2.

[0027] In this invention, the pre-oxidation temperature is preferably 300~320 ℃, more preferably 300~310 ℃, and even more preferably 300 ℃; the pre-oxidation time is preferably 1~3 h, more preferably 1~1.5 h, and even more preferably 1 h.

[0028] The present invention also provides a superamphilic coal-based fiber membrane prepared by the above preparation method.

[0029] The present invention also provides an application of an ultra-amphiphilic coal-based fiber membrane prepared by the above preparation method in air purification.

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a superamphilic coal-based fiber membrane, the preparation flowchart of which is shown below. Figure 1 As shown, it includes the following steps: 1 g of polyacrylonitrile and 1 g of oxidized coal were dissolved in 10 mL of N,N-dimethylformamide to obtain spinning solution A; Dissolve 0.6 g of polyacrylonitrile and 0.15 g of candle ash nanoparticles in 10 mL of N,N-dimethylformamide to obtain spinning solution B; Spinning solution A and spinning solution B are placed in opposing micro-propellers, and electrospinning of spinning solution A and spinning solution B is performed simultaneously by a conjugate electrospinning device. The volume ratio of spinning solution A to spinning solution B is controlled to be 2:1 by adjusting the propeller speed. The electrospinning conditions are: temperature 35 ℃, humidity 15%, receiving distance 18 cm, negative voltage -2.5 kV, and positive voltage 13.5 kV, to obtain fiber precursor. The fiber filaments were placed in a muffle furnace and heated at a rate of 2 °C / min. -1 Pre-oxidation was carried out at a temperature of 300 ℃ for 1 h to obtain a superamphilic coal-based fiber membrane, denoted as UFRCFM. 2:1 .

[0033] Example 2

[0034] This embodiment provides a method for preparing a superamphilic coal-based fiber membrane, specifically referring to Example 1, except that the volume ratio of spinning solution A and spinning solution B is 1:1. The resulting superamphilic coal-based fiber membrane is denoted as UFRCFM.1:1 .

[0035] Example 3

[0036] This embodiment provides a method for preparing a superamphilic coal-based fiber membrane, specifically referring to Example 1, except that the volume ratio of spinning solution A to spinning solution B is 1:2, and the resulting superamphilic coal-based fiber membrane is denoted as UFRCFM. 1:2 .

[0037] Example 4

[0038] This embodiment provides a method for preparing a superamphilic coal-based fiber membrane, specifically referring to Example 1, except that the volume ratio of spinning solution A and spinning solution B is 1:3, and the resulting superamphilic coal-based fiber membrane is denoted as UFRCFM. 1:3 .

[0039] Example 5

[0040] This embodiment provides a method for preparing a superamphilic coal-based fiber membrane, as detailed in Example 1, except that the volume ratio of spinning solution A to spinning solution B is 1:4. The resulting superamphilic coal-based fiber membrane is denoted as UFRCFM. 1:4 .

[0041] Comparative Example 1

[0042] This comparative example provides a method for preparing an ultraamophilic coal-based fiber membrane, as detailed in Example 3. The difference is that the spinning solution B does not contain candle ash nanoparticles, and the resulting ultraamophilic coal-based fiber membrane is designated as UFRCFM-C.

[0043] Figure 2 In the middle, 'a' represents the UFRCFM of Example 3. 1:2 The SEM images show that the coal-based fibers and ultrafine fibers exhibit a random distribution, and the ultrafine fiber surface also contains a large number of CSNPs. (UFRCFM) 1:2 The diameters of the medium fibers are 591.5 nm and 60.4 nm, respectively. Figure 2 (b) The surface of the fiber membrane not only fully exposes the coal-based fibers but also contains a large number of ultrafine fibers with a rough structure, thus forming a typical hierarchical micro / nano structure.

[0044] Figure 3 Figure a shows the SEM image of UFRCFM-C in Comparative Example 1. It can be seen that the distribution of coal-based fibers and ultrafine fibers is relatively uniform, and the fiber surfaces are all relatively smooth. The fiber diameters are 610.8 nm and 89.0 nm, respectively. Figure 3 (b) with UFRCFM 1:2 In comparison, the diameter of coal-based fibers in fiber membranes is not significantly different, while the diameter of ultrafine fibers increases by 47.4%.

[0045] UFRCFM in Example 3 1:2 It exhibits superhydrophilicity in air, and water droplets in UFRCFM... 1:2 The surface can be completely absorbed in just 0.5 seconds. Figure 4 (a) Similarly, oil droplets in UFRCFM 1:2 The surface spreads completely in just 0.1 seconds, demonstrating excellent superoleophilicity. Figure 4 (b)

[0046] Figure 5 UFRCFM for Example 3 1:2 The pore size and porosity of UFRCFM-C compared to Comparative Example 1, UFRCFM 1:2 The pore size of the fibrous material is 1.6 μm, and the porosity is 90.1%; the pore size of UFRCFM-C is 2.5 μm, and the porosity is 92.3%. After adding CSNPs, the diameter of the ultrafine fibers decreased by 47.4%, while the diameter of coal-based fibers did not differ significantly. Therefore, in UFRCFM... 1:2 In the three-dimensional space, coal-based fibers and ultrafine fibers are stacked more densely, resulting in smaller pore size and porosity.

[0047] Figure 6 UFRCFM for Example 3 1:2 The stress-strain curves of UFRCFM-C and Comparative Example 1, UFRCFM 1:2 The tensile strength of the former is as high as 16.3 MPa, while the tensile strength of UFRCFM-C is 8.8 MPa, which is much lower than that of UFRCFM. 1:2 The difference in their mechanical properties is due to UFRCFM 1:2 The diameter of the microfibers is smaller, and the spatial distribution of coal-based fibers and microfibers is more compact. Additionally, UFRCFM... 1:2 The surface of ultrafine fibers contains a large number of graded rough structures, which increases the contact area between ultrafine fibers and coal-based fibers, thus UFRCFM 1:2 The interfiber sliding resistance in UFRCFM-C is higher than that in UFRCFM. 1:2 Its mechanical properties are far superior to those of UFRCFM-C.

[0048] Through such Figure 7 The homemade filtration device shown was used to investigate the ability of the fiber membranes of Examples 1-5 and Comparative Example 1 to capture oily smoke particles, wherein the oily smoke particles (PM) 1.0 PM 2.5 and PM 10 The filtration performance of the fiber membrane was evaluated by filtration efficiency and pressure drop, using material produced from incompletely burned corrugated paper. The effective filtration area of ​​the fiber membrane was 19.23 cm².3 The initial concentration of the smoke before filtration was maintained at approximately 5000 μg / cm³. -3 The filtration time was approximately 4 minutes. The smoke concentration before and after filtration was measured using a laser particle size analyzer, and the filtration efficiency was calculated using Formula 1. (1) Where, N B and N A These represent the concentrations of different sizes of particulate matter in the air before and after filtration, respectively, and E represents the filtration efficiency.

[0049] First, at an airflow rate of 15 L / min -1 To investigate the filtration performance of fiber membranes under certain conditions, from Figure 8 As can be seen in Figure a, with the increase of the proportion of ultrafine fibers, the filtration efficiency of the fiber membrane for smoke particles gradually increases, especially for PM2.5. 1.0 The filtration efficiency increased from the initial 95.3% (UFRCFM). 2:1 The percentage rapidly increased to 99.1% (UFRCFM). 1:2 During this process, the filtration pressure drop increased from 6 Pa (UFRCFM). 2:1 Increased to 24 Pa (UFRCFM) 1:2 Nevertheless, UFRCFM 1:2 The pressure drop and filtration efficiency are still superior to those of similar fiber membranes previously reported. Compared to commercially available disposable medical masks and activated carbon masks, UFRCFM... 1:2 It has higher filtration efficiency and lower pressure drop. Figure 10 ).

[0050] Figure 8 b is UFRCFM 1:2 Filtration performance at different airflow velocities. When the airflow velocity is 5~15 L / min... -1 At this time, the filtration efficiency of the fiber membrane for smoke particles only decreased slightly. When the airflow rate exceeded 15 L / min... -1 Subsequently, the separation efficiency of the fiber membrane began to decrease. However, even at an airflow rate of 25 L / min... -1 In the case of UFRCFM 1:2 The filtration efficiency for smoke particles remains above 99.70% (PM2.5). 1.0 PM 2.5 PM 10 The filtration efficiencies were 99.78%, 99.81%, and 99.85%, respectively, and the pressure drop was only 55 Pa, still demonstrating good filtration performance. Based on this, further investigation of UFRCFM was conducted. 1:2 Continuous filtration performance, with the airflow rate set at 15 L / min-1 In a continuous filtration experiment of 40 minutes ( Figure 8 c), fiber membrane for PM 1.0 PM 2.5 PM 10 The filtration efficiency remained essentially constant, and the pressure drop was maintained at around 24 Pa. Under the same conditions, UFRCFM-C performed well in a continuous filtration experiment for 40 minutes. Figure 8 (d) Its filtration performance remains basically unchanged, but its filtration efficiency is lower than that of UFRCFM. 1:2 .

[0051] UFRCFM 1:2 After prolonged filtration, obvious contamination appeared on the surface. Figure 9 (a) will severely pollute UFR CFM 1:2 After simple washing and drying, the oily smoke particles adhering to the fiber surface were basically cleaned up. Figure 9 (b) Then, the continuous filtration performance after cleaning was further investigated, and the results showed that UFRCFM 1:2 The filtration efficiency and pressure drop remain basically unchanged. Figure 9 (c) indicates UFRCFM 1:2 It exhibits good cycle stability and renewability.

[0052] When wearing a filtering mask, its radiative cooling and breathability are crucial for wearing comfort. Therefore, UFRCFM... 1:2 The fiber membrane mask was used as a meltblown layer to make a filter mask, and an infrared thermal imager was used to evaluate the radiation characteristics when wearing the mask. Figure 11 As shown in Figure c, when exhaling rapidly while wearing a fiber membrane mask, the infrared image shows that the surface temperature of the mask can reach over 40°C, while under the same conditions, the temperature of a medical mask ( Figure 11 a) and activated carbon masks ( Figure 11 The lower temperature in section b) is mainly due to the dual-scale diameter and high porosity of the fiber membrane, which significantly reduces air resistance, thus enabling the fiber membrane mask to exhibit better radiative cooling and breathability. In addition, the fiber membrane is superhydrophilic and superoleophilic in the air, quickly absorbing water vapor exhaled from the mouth, sweat, and oil produced by the skin, ensuring the wearer's face remains fresh and dry at all times, greatly improving wearing comfort.

[0053] Figure 12 For UFRCFM 1:2A schematic diagram of smoke particle filtration. Analysis results show that fiber membrane filtration of smoke particles exhibits "high efficiency and low resistance" characteristics. The smoke particle capture mechanism has two aspects: First, a passive capture mechanism, where submicron coal-based fibers facilitate the formation of larger pores and a loose structure to reduce air resistance. The coarse ultrafine fibers randomly dispersed within the pores of the coal-based fibers not only reduce the pore size of the fiber membrane but also increase the UFRCFM (Ultra-Fluorescent Fluid Membrane). 1:2 Passive capture capability for smoke particles. Furthermore, according to gas kinetic theory, when the fiber diameter is close to the free path of air molecules (65 nm), a more pronounced slip phenomenon occurs, and the motion state of air molecules transforms into a slip flow state. Morphology analysis shows that the diameter of the ultrafine fiber is 60.4 nm, therefore, air molecules in UFRCFM... 1:2 The internal flow bypasses the fibers, thus greatly reducing the drag force caused by impacts, therefore UFRCFM 1:2 The filtration resistance is low. Secondly, the active capture mechanism, as shown by infrared results, leads to UFRCFM. 1:2 The surface contains a large number of highly polar functional groups (such as -OH, -C=O, -CO, etc.). These polar groups may adsorb / capture smoke particles through hydrogen bonding, π-π stacking, or chemical bonding. Furthermore, these forces increase the adhesion between oily smoke particles and fibers, ensuring that the fiber membrane has durable filtration performance and multiple filtration cycles.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a superamphilic coal-based fiber membrane, characterized in that, Includes the following steps: Polyacrylonitrile and coal oxide were dissolved in N,N-dimethylformamide to obtain spinning solution A; Polyacrylonitrile and candle ash nanoparticles were dissolved in N,N-dimethylformamide to obtain spinning solution B; Spinning solution A and spinning solution B are placed in opposing micro-propellers, and electrospinning solution A and spinning solution B are simultaneously performed by a conjugate electrospinning device to obtain fiber filaments. The fiber precursor was pre-oxidized to obtain an ultra-amphiphilic coal-based fiber membrane.

2. The method for preparing a superamphilic coal-based fiber membrane according to claim 1, characterized in that, The ratio of polyacrylonitrile, oxidized coal, and N,N-dimethylformamide in the spinning solution A is 1 g: 1~1.5 g: 10 mL.

3. The method for preparing a superamphilic coal-based fiber membrane according to claim 1, characterized in that, The ratio of polyacrylonitrile, candle ash nanoparticles, and N,N-dimethylformamide in the spinning solution B is 0.6 g: 0.1~0.5 g: 10 mL.

4. The method for preparing a superamphilic coal-based fiber membrane according to claim 1, characterized in that, The weight-average molecular weight of polyacrylonitrile in spinning solution A and spinning solution B is 150,000.

5. The method for preparing a superamphilic coal-based fiber membrane according to claim 1, characterized in that, The conditions for electrospinning are: temperature 30~40 ℃, humidity 10~20%, receiving distance 15~20 cm, and voltage -3.5~+14 kV.

6. The method for preparing a superamphilic coal-based fiber membrane according to claim 1, characterized in that, The volume ratio of spinning solution A to spinning solution B is 1~2:1~4.

7. The method for preparing a superamphilic coal-based fiber membrane according to claim 1, characterized in that, The pre-oxidation temperature is 300~320 ℃; the pre-oxidation time is 1~3 h.

8. A superamphilic coal-based fiber membrane prepared by the preparation method according to any one of claims 1 to 7.

9. The application of an ultra-amphiphilic coal-based fiber membrane prepared by the preparation method according to any one of claims 1 to 7 or the ultra-amphiphilic coal-based fiber membrane according to claim 8 in air purification.

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