A fiber membrane prepared based on in situ growth and its application in adsorption of toluene

Abstract

The invention discloses a fiber membrane prepared based on in-situ growth and its application in adsorbing toluene, and belongs to the technical field of functional textiles. The method for preparing fiber membrane based on in-situ growth in the present invention comprises the following steps: (1) adding 2-aminoterephthalic acid and polyacrylonitrile in a solvent, mixing uniformly, and obtaining a spinning solution; (2) subjecting the spinning solution to electrostatic spinning, drying, and obtaining a fiber membrane; (3) placing the fiber membrane in an ethylene glycol solution, adding ethylenediamine, and performing thermal crosslinking; after thermal crosslinking is completed, washing, drying, and obtaining a fiber membrane after crosslinking; (4) placing the fiber membrane after crosslinking in a solvent, adding zirconium oxychloride, 2-aminoterephthalic acid, and benzoic acid, performing in-situ growth, and obtaining a fiber membrane prepared based on in-situ growth. The fiber membrane prepared based on in-situ growth of the present invention has a high adsorption capacity for toluene, is recyclable, and can be recycled.

Description

Technical Field

[0001] The invention relates to a fiber membrane prepared based on in-situ growth and application thereof in toluene adsorption, belonging to the technical field of functional textiles. Background Art

[0002] VOCs (volatile organic compounds) are considered to be one of the most harmful pollutants to human health and ecosystems. Toluene, in particular, is a pollutant that urgently needs to be addressed due to its high toxicity and wide range of sources (chemical production, paint production, house decoration, etc.). It is reported that exposure to toluene for more than 8 hours can have negative health effects and even pose a hidden risk of cancer in humans. In order to reduce the emission of benzene-based VOCs, several methods are available, including adsorption, catalytic oxidation, and photocatalysis. Among them, adsorption is considered to be the most effective and economical technology for controlling VOC pollution due to its simple operation, high cost-effectiveness, and low energy consumption.

[0003] Traditional materials for toluene adsorption include activated carbon, molecular sieves, diatomaceous earth, biochar and resins, which are widely used due to their simple preparation methods. However, these materials often face significant limitations in their applications, such as low adsorption capacity, easy clogging, poor selectivity and regeneration challenges. In contrast, metal organic frameworks (MOFs) have significant advantages, with surface areas of up to 10,000 m 2 / g, and its porosity can reach 0.9cm 3 / g, far exceeding traditional adsorbent materials. MOFs also offer advantages such as water stability, good chemical and thermal stability, and are widely used in gas storage, catalysis, drug delivery, and wastewater treatment. UiO-66 differs from other MOFs in that its structural unit, consisting of a [Zr6O4(OH)4] metal cluster coordinated by 12 terephthalic acid (H2BDC) groups, possesses the highest coordination number between organic ligands and metal clusters. The Zr-O bond in UiO-66 is highly water-stable and possesses numerous active adsorption sites. Furthermore, UiO-66 is easily modified, allowing for the desired physical and chemical properties to be achieved through functional group modification. By modifying the ligand with other functional groups and coordinating them with Zr, functionalized Zr-MOFs such as UiO-66-NH2 and UiO-66-NO2 can be prepared. Despite its many advantages as an adsorbent, UiO-66 is mostly obtained in powder form, limiting its use and recycling in large-scale applications such as gas adsorption.

[0004] Currently, there are two main ways to combine MOF with nanofibers:

[0005] (1) Direct electrospinning, that is, adding preformed MOF to the polymer spinning precursor solution, and directly obtaining the composite nanofiber membrane by electrospinning. This method is simple to operate and has few limitations, but MOF particles are prone to aggregation, resulting in blockage during spinning. Moreover, since the diameter of MOF particles is smaller than that of the fiber, they are usually shielded inside the fiber and cannot function.

[0006] (2) In situ growth, that is, the pure polymer fiber membrane obtained by spinning is immersed in a solution containing metal salts and organic ligands, and MOF is grown in situ on the fiber surface under high temperature and high pressure. This method greatly reduces the degree of MOF aggregation while increasing the MOF loading, and can improve the compatibility of MOF with polymer fibers. It is a more promising preparation method, but MOF is difficult to grow on the surface of ordinary polymers. It is usually necessary to embed MOF growth seeds in the fiber, such as adding metal salts or organic ligands to the spinning precursor solution to promote MOF growth. The difficulty of growing different MOF materials is also completely different.

[0007] At present, most studies are to prepare composite membranes by directly blending MOF powder with polymer matrix. However, in this process, the polymer will fully wrap and block the pore size of MOF, thereby reducing the adsorption performance, such as:

[0008] Patent CN 110496541 A discloses a modified composite fiber membrane for oil-water separation and its preparation method. NH2-UiO-66(Zr) is blended with PAN and directly electrospun to produce a superhydrophobic, superoleophilic nanofiber membrane with excellent oil-water separation properties. The composite fiber membrane has an adsorption capacity of 33.7 g / g for silicone oil, but the adsorption capacity for volatile organic compounds has not been studied.

[0009] Patent CN 118416713 A discloses a high-throughput, fast-adsorption PAN / PEI / UiO-66-NH2 adsorption membrane for its preparation and application in the adsorption of Cr(VI). Direct electrospinning is used to encapsulate MOFs (UiO-66-NH2) in fibers. The PAN / PEI / UiO-66-NH2 adsorption membrane achieves a flux of 1150 L / m at a pressure of 0.08 MPa while simultaneously removing Cr(VI) at an industrial emission standard. -2 *h -1 , but the adsorption amount of volatile organic compounds has not been studied.

[0010] Moreover, the adsorption of metal ions, adsorption of grease and adsorption of gas are completely different; the adsorption of metal ions is through ion exchange; the adsorption of grease is through van der Waals force or π-π stacking; the adsorption of gas is intermolecular force, such as van der Waals force; that is: adsorbents that adsorb metal ions, adsorb grease and adsorb gas are not universal.

[0011] Therefore, there is an urgent need to develop an adsorption material that has a large toluene adsorption capacity and is recyclable and reusable. Summary of the Invention

[0012] [Technical Issues]

[0013] Conventional toluene adsorption materials have problems such as “low adsorption capacity, easy clogging, poor selectivity and regeneration challenges”;

[0014] Toluene adsorbed by MOF powder is difficult to recycle;

[0015] The composite membrane formed by MOF powder and polymer matrix has low adsorption performance for toluene.

[0016] [Technical solution]

[0017] In order to solve the above problems, the present invention provides a fiber membrane prepared based on in-situ growth, which can be used to adsorb toluene, has good adsorption effect and can be recycled.

[0018] The first object of the present invention is to provide a method for preparing a fiber membrane based on in situ growth, comprising the following steps:

[0019] (1) adding 2-aminoterephthalic acid and polyacrylonitrile to a solvent and mixing them uniformly to obtain a spinning solution;

[0020] (2) electrospinning the spinning solution and drying it to obtain a fiber membrane;

[0021] (3) placing the fiber membrane in an alcohol solution, adding ethylenediamine, and performing thermal crosslinking; after the thermal crosslinking is completed, washing and drying to obtain a crosslinked fiber membrane;

[0022] (4) The cross-linked fiber membrane is placed in a solvent, and zirconium oxychloride, 2-aminoterephthalic acid, and benzoic acid are added to perform in situ growth to obtain a fiber membrane prepared based on in situ growth.

[0023] In one embodiment of the present invention, the solvent in step (1) is one or both of N,N-dimethylformamide and acetone.

[0024] In one embodiment of the present invention, the ratio of the solvent to polyacrylonitrile in step (1) is 8-12 mL:1 g, more preferably 1 mL:1 g.

[0025] In one embodiment of the present invention, the mass ratio of 2-aminoterephthalic acid to polyacrylonitrile in step (1) is 0.10-0.20:1, more preferably 0.15:1.

[0026] In one embodiment of the present invention, the temperature for uniform mixing in step (1) is 55-65°C, more preferably 60°C.

[0027] In one embodiment of the present invention, the parameters of electrospinning in step (2) are:

[0028] The voltage is 10-15 kV, the injection speed is 0.2-2 mL / h, the needle diameter is 0.2-1 mm, the receiving distance is 10-20 cm, the receiving roller speed is 60-240 rpm, the ambient temperature is 25-40 ° C, and the relative humidity is 15-60%.

[0029] In one embodiment of the present invention, the drying in step (2) is carried out at 60-100° C. to volatilize the solvent.

[0030] In one embodiment of the present invention, the volume fraction of the alcohol solution in step (3) is 60-80%, more preferably 75%.

[0031] In one embodiment of the present invention, the alcohol solution in step (3) is an ethylene glycol solution or a propylene glycol solution, and the solvent is water.

[0032] In one embodiment of the present invention, the volume ratio of the alcohol solution to ethylenediamine in step (3) is 1 mL:0.8-1.2 μL; more preferably 1 mL:1 μL.

[0033] In one embodiment of the present invention, the ratio of the fiber membrane to the alcohol solution in step (3) is 100 mg: 80-120 mL.

[0034] In one embodiment of the present invention, the thermal crosslinking in step (3) is carried out at 130-140° C. for 1-3 hours, more preferably at 135° C. for 2 hours.

[0035] In one embodiment of the present invention, the washing in step (3) is performed using ethanol and water.

[0036] In one embodiment of the present invention, the drying in step (3) is carried out at 60-100°C.

[0037] In one embodiment of the present invention, the solvent in step (4) is one or both of N,N-dimethylformamide and acetone.

[0038] In one embodiment of the present invention, the ratio of the cross-linked fiber membrane to the solvent in step (4) is 100 mg: 80-120 mL.

[0039] In one embodiment of the present invention, the mass ratio of the cross-linked fiber membrane, zirconium oxychloride, 2-aminoterephthalic acid, and benzoic acid in step (4) is 0.1:0.5-1.0:0.3-0.7:1-1.5; more preferably 0.1:0.75:0.5:1.25.

[0040] In one embodiment of the present invention, the in-situ growth in step (4) is carried out at 90-110° C. for 20-30 h.

[0041] The second object of the present invention is a fiber membrane prepared based on in-situ growth and obtained by the method described in the present invention.

[0042] In one embodiment of the present invention, the fiber membrane is a PAN nanofiber with a UiO-66-NH2 crystal structure loaded on the surface.

[0043] The third object of the present invention is the application of the fiber membrane prepared based on in-situ growth in the field of environmental pollution.

[0044] The fourth object of the present invention is to provide a toluene adsorbent, which uses the fiber membrane prepared based on in-situ growth according to the present invention.

[0045] The fifth object of the present invention is to provide a method for improving the toluene adsorption performance of MOF in polymers, which uses the fiber membrane prepared based on in situ growth according to the present invention.

[0046] The sixth object of the present invention is to provide a method for improving the toluene adsorption performance of polyacrylonitrile fiber membrane, which adopts the fiber membrane prepared based on in situ growth as described in the present invention.

[0047] [Beneficial Effects]

[0048] (1) The present invention loads the UiO-66-NH2 crystal structure on the surface of PAN nanofibers through electrospinning and in situ growth, so that it has good adsorption performance for toluene.

[0049] (2) The fiber membrane prepared based on in situ growth described in the present invention has a high adsorption capacity for toluene and is recyclable and can be recycled.

[0050] (3) The specific surface area of ​​the fiber membrane prepared based on in situ growth according to the present invention reaches 256m 2 / g; the adsorption capacity for toluene reached 188 mg / g, and the adsorption rate reached 4.3×10 -3 / min; and, after five adsorptions, the adsorption capacity for toluene only decreased by 3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is the XRD pattern of the fiber membrane prepared based on in situ growth in Example 1.

[0052] Figure 2 This is the infrared spectrum of the fiber membrane prepared based on in situ growth in Example 1.

[0053] Figure 3 This is the SEM image of the fiber membrane prepared based on in situ growth in Example 1.

[0054] Figure 4 This is the nitrogen adsorption-desorption curve of the fiber membrane prepared based on in situ growth in Example 1.

[0055] Figure 5 This is the adsorption effect of the fiber membrane prepared based on in situ growth in Example 1.

[0056] Figure 6 Comparison of the adsorption isotherms, adsorption kinetics (a), adsorption capacity (b) and velocity (c) of toluene for the fiber membranes prepared in Example 1 and Comparative Example 3.

[0057] Figure 7 The effect of different amounts of 2-aminoterephthalic acid on the performance of fiber membrane.

[0058] Figure 8 This is the SEM image of the fiber membrane obtained in Comparative Example 6.

[0059] Figure 9 This is the SEM image of the fiber membrane obtained in Comparative Example 7.

[0060] Figure 10 This is the SEM image of the fiber membrane obtained in Comparative Example 12. DETAILED DESCRIPTION

[0061] The following describes preferred embodiments of the present invention. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0062] Test method:

[0063] 1. Test of toluene adsorption performance (adsorption capacity, adsorption speed):

[0064] Preprocessing:

[0065] The samples were evenly placed in a quartz crucible. In a closed system, high-purity nitrogen (400 sccm) was used to purge the samples at 150°C for 180 minutes, with an average flow rate of 50 sccm.

[0066] test:

[0067] After the pretreatment, the sample environment was lowered to 25°C, and wet nitrogen was used to bubble into toluene. The nitrogen-carried toluene vapor (40 sccm in total) was mixed with dry nitrogen (360 sccm), that is, the P / P0 of 25°C toluene was 0.1. The gas was continuously blown onto the sample surface for adsorption. After the adsorption equilibrium was reached, the four-way valve switched the flow rate, and the wet flow rate + vapor flow rate (80 sccm in total) was re-mixed with the dry flow rate (320 sccm) and blown onto the sample surface. The adsorption process of 25°C toluene with a P / P0 of 0.2 was carried out until the adsorption equilibrium was reached.

[0068] According to the above process, the flow ratios of dry and wet paths are adjusted to P / P0 of toluene at 25°C: 0.3-0.4-0.5-0.6-0.7-0.8-0.9-0.8-0.8-0.6-0.5-0.4-0.3-0.2-0.1.

[0069] During the test, the samples at different analysis positions are continuously weighed using the high-resolution balance inside the instrument. The obtained weighing value data is processed by software and the buoyancy is calculated to obtain the adsorption capacity-time curve. The saturated adsorption capacity at each pressure point is then selected to obtain the isotherm.

[0070] 2. Test of toluene circulation performance:

[0071] Preprocessing:

[0072] The samples were evenly placed in a quartz crucible. In a closed system, high-purity nitrogen (400 sccm) was used to purge the samples at 150° C. for 180 min, with an average flow rate of 50 sccm.

[0073] test:

[0074] After pretreatment, the sample temperature was lowered to 25°C. Wet-line nitrogen was bubbled through toluene. A nitrogen-carrying toluene vapor (320 sccm total) was mixed with dry-line nitrogen (80 sccm) at a ratio of 0.8 for the 25°C toluene P / P ratio. This gas was continuously blown onto the sample surface to allow adsorption. After reaching adsorption equilibrium, the four-way valve was switched to high-purity nitrogen (400 sccm) and the sample surface was desorbed, with the 25°C toluene P / P ratio at 0, until desorption equilibrium was reached. This process was repeated five times.

[0075] During the test, the samples at different analysis positions are continuously weighed using the high-resolution balance inside the instrument. The obtained weighing value data is processed by software and the buoyancy is calculated to obtain the adsorption amount-time curve.

[0076] 3. Test of nitrogen adsorption and desorption curve:

[0077] 77K nitrogen adsorption and desorption test process:

[0078] Install the sample tube containing the sample on the instrument, add liquid nitrogen to the liquid nitrogen cup to the scale line, set the degassing plan and test plan, and click Start after the sample tube passes the leak test to enter the fully automatic in-situ degassing test process;

[0079] (1) He gas test free space volume;

[0080] (2) In-situ vacuum heating degassing (pressure-controlled heating to prevent flying);

[0081] (3) Enter the adsorption-desorption test;

[0082] According to the P / P0 relative pressure point set in the test plan, it gradually changes from 0 to nearly 1 atmosphere. The pressure change before and after the sample adsorption is measured with a high-precision pressure sensor, and then the adsorption or desorption amount of the gas is calculated according to the gas state equation; the adsorption amount-relative pressure curve is obtained, and the BET specific surface area and pore size distribution are calculated according to the nitrogen adsorption theory calculation formula. Raw materials used in the examples are:

[0083] N,N-dimethylformamide: ≥97.5, AR;

[0084] 2-aminoterephthalic acid: AR;

[0085] Polyacrylonitrile: powder, average Mw = 150,000, AR;

[0086] Ethylenediamine: AR;

[0087] Zirconium oxychloride: GR;

[0088] Benzoic acid: AR.

[0089] In the examples, solutions without specific solvents are based on water, and % without specific meanings are percentages by mass. Reactions without specific reaction temperatures are room temperature reactions, which are 20-30°C.

[0090] Example 1

[0091] A method for preparing a fiber membrane based on in-situ growth comprises the following steps:

[0092] (1) Add 0.15 g of 2-aminoterephthalic acid and 1 g of polyacrylonitrile to 10 mL of N,N-dimethylformamide, and stir and mix thoroughly at 60°C to obtain a spinning solution;

[0093] (2) The spinning solution was electrospun at a voltage of 12 kV, a push injection rate of 1 mL / h, a needle diameter of 0.4 mm, a receiving distance of 15 cm, a receiving roller speed of 100 rpm, an ambient temperature of 30°C, and a relative humidity of 40%; the solution was placed in a vacuum oven at 80°C to dry and volatilize the solvent in the fiber, thereby obtaining a fiber membrane (BP) containing 15% by mass of 2-aminoterephthalic acid;

[0094] (3) 100 mg of the fiber membrane was placed in 100 mL of 75% ethylene glycol solution, 100 μL of ethylenediamine was added, and thermal cross-linking was performed at 135°C for 2 h. After the thermal cross-linking was completed, the membrane was washed with ethanol and deionized water three times each, and dried in a vacuum oven at 80°C to obtain the cross-linked fiber membrane (ABP).

[0095] (4) 100 mg of the cross-linked fiber membrane was placed in 100 mL of N,N-dimethylformamide, and 0.75 g of zirconium oxychloride, 0.5 g of 2-aminoterephthalic acid, and 1.25 g of benzoic acid were added to the reactor at 100 °C for in situ growth for 24 h to obtain a fiber membrane prepared based on in situ growth (UiO-66-NH2@ABP).

[0096] The fiber membrane prepared based on in situ growth was tested for performance, and the test results are as follows:

[0097] (1) Surface structure characterization:

[0098] The XRD pattern of the fiber membrane prepared based on in situ growth is shown in Figure 1 ,from Figure 1 It can be seen that characteristic peaks of 7.05° and 8.14° were observed in the fiber membrane, corresponding to the characteristic peaks of UiO-66-NH2, proving the synthesis of MOF.

[0099] The infrared spectrum of the fiber membrane prepared based on in situ growth is as follows Figure 2 .from Figure 2 It can be seen that at 620cm -1 and 770cm -1 The characteristic absorption peak at is related to the Zr-O bond, which means that UiO-66-NH2 is successfully synthesized on the fiber surface.

[0100] Combined, Figure 1 and Figure 2 It can be seen that UiO-66-NH2 does exist on the surface of the fiber membrane prepared in Example 1.

[0101] (2) Surface morphology characterization:

[0102] The SEM image of the fiber membrane prepared based on in situ growth is shown in Figure 3 .

[0103] The nitrogen adsorption and desorption curves of the fiber membrane prepared based on in situ growth are as follows: Figure 4 .from Figure 4 It can be seen that the specific surface area of ​​the fiber membrane (UiO-66-NH2@ABP) prepared based on in situ growth is greatly improved, reaching 256m 2 / g.

[0104] (3) Characterization of adsorption performance:

[0105] The adsorption effect of fiber membrane prepared based on in situ growth is as follows Figure 5 ,from Figure 5 It can be seen that the adsorption capacity of the fiber membrane prepared based on in situ growth for toluene reaches 178 mg / g, and the adsorption rate reaches 4.3×10 -3 / min; and, after five adsorptions, the adsorption capacity for toluene only decreased by 3%.

[0106] Example 2

[0107] The amount of 2-aminoterephthalic acid in step (1) of Example 1 was adjusted to 0.10 g, and the other contents remained the same as in Example 1 to obtain a fiber membrane prepared based on in situ growth.

[0108] Example 3

[0109] The amount of 2-aminoterephthalic acid in step (1) of Example 1 was adjusted to 0.20 g, and the other ingredients were kept consistent with Example 1 to obtain a fiber membrane prepared based on in situ growth.

[0110] Comparative Example 1

[0111] A method for preparing a fiber membrane based on direct spinning comprises the following steps:

[0112] (1) 0.75 g zirconium oxychloride, 0.5 g 2-aminoterephthalic acid, and 1.25 g benzoic acid were added to 10 mL N,N-dimethylformamide and reacted in a reactor at 100 °C for 24 h to synthesize the metal organic framework (MOF) powder: UiO-66-NH2;

[0113] (2) Add 0.08 g of UiO-66-NH2 and 0.8 g of polyacrylonitrile powder to 10 mL of N,N-dimethylformamide and stir thoroughly until the liquid is uniform to obtain a spinning solution;

[0114] (3) The spinning solution was subjected to electrospinning at a voltage of 12 kV, an injection rate of 1 mL / h, a needle diameter of 0.4 mm, a receiving distance of 15 cm, a receiving roller speed of 100 rpm, an ambient temperature of 30°C, and a relative humidity of 40%; the solution was placed in a vacuum oven at 80°C to dry and volatilize the solvent in the fiber, thereby obtaining a fiber membrane prepared based on direct spinning.

[0115] Comparative Example 2

[0116] A method for preparing a fiber membrane based on direct spinning comprises the following steps:

[0117] (1) 0.75 g zirconium oxychloride, 0.5 g 2-aminoterephthalic acid, and 1.25 g benzoic acid were added to 10 mL N,N-dimethylformamide and reacted in a reactor at 100 °C for 24 h to synthesize the metal organic framework (MOF) powder: UiO-66-NH2;

[0118] (2) Add 0.24 g of UiO-66-NH2 and 0.8 g of polyacrylonitrile powder to 10 mL of N,N-dimethylformamide and stir thoroughly until the liquid is uniform to obtain a spinning solution;

[0119] (3) The spinning solution was subjected to electrospinning at a voltage of 12 kV, an injection rate of 1 mL / h, a needle diameter of 0.4 mm, a receiving distance of 15 cm, a receiving roller speed of 100 rpm, an ambient temperature of 30°C, and a relative humidity of 40%; the solution was placed in a vacuum oven at 80°C to dry and volatilize the solvent in the fiber, thereby obtaining a fiber membrane prepared based on direct spinning.

[0120] Comparative Example 3

[0121] A method for preparing a fiber membrane based on direct spinning comprises the following steps:

[0122] (1) 0.75 g zirconium oxychloride, 0.5 g 2-aminoterephthalic acid, and 1.25 g benzoic acid were added to 10 mL N,N-dimethylformamide and reacted in a reactor at 100 °C for 24 h to synthesize the metal organic framework (MOF) powder: UiO-66-NH2;

[0123] (2) Add 0.40 g of UiO-66-NH2 and 0.8 g of polyacrylonitrile powder to 10 mL of N,N-dimethylformamide and stir thoroughly until the liquid is uniform to obtain a spinning solution;

[0124] (3) The spinning solution was subjected to electrospinning at a voltage of 12 kV, an injection rate of 1 mL / h, a needle diameter of 0.4 mm, a receiving distance of 15 cm, a receiving roller speed of 100 rpm, an ambient temperature of 30°C, and a relative humidity of 40%; the solution was placed in a vacuum oven at 80°C to dry and volatilize the solvent in the fiber, thereby obtaining a fiber membrane prepared based on direct spinning.

[0125] Comparative Example 4

[0126] The amount of 2-aminoterephthalic acid in step (1) of Example 1 was adjusted to 0.05 g, and the other ingredients were kept consistent with Example 1 to obtain a fiber membrane prepared based on in situ growth.

[0127] The fiber membranes obtained in Example 1 and Comparative Examples 1-5 were subjected to performance tests, and the test results are as follows:

[0128] Figure 6 Comparison of the adsorption isotherms, adsorption kinetics, and adsorption capacity and rate of toluene by the fiber membranes prepared in Example 1 and Comparative Example 3. Figure 6 It can be seen that the adsorption effect of the fiber membrane prepared by in situ growth is much higher than that of direct spinning.

[0129] Figure 7 The effect of different amounts of 2-aminoterephthalic acid on the performance of fiber membranes. Figure 7 It can be seen that: at 0.05g, MOF grows too little and the adsorption performance is very low; at 0.2g, MOF grows too much, resulting in a decrease in the mechanical properties of the fiber (breaking strength of 1050kPa, elongation at break of 16%); at 0.15g, it has good adsorption performance; the MOF material on the fiber surface is relatively uniform and has good mechanical properties, with a breaking strength of 1200kPa and an elongation at break of 20%.

[0130] Table 1

[0131] example Adsorption capacity (mg / g) <![CDATA[Adsorption rate (10 -3 ×min -1 )]]> Example 1 178 4.3 Example 2 54 3.5 Example 3 166 3.9 Comparative Example 1 41 0.8 Comparative Example 2 77 1.3 Comparative Example 3 103 2.9 Comparative Example 4 19 1.9 <![CDATA[UiO-66-NH2 (powder)]]> 454 7.6

[0132] Comparative Example 6

[0133] The temperature of the in-situ growth in step (4) of Example 1 was adjusted to 80° C., and the other steps were kept consistent with Example 1 to obtain a fiber membrane prepared based on in-situ growth.

[0134] The SEM images of the obtained fiber membrane are shown in Figure 8 ,from Figure 8 It can be seen that there is too little MOF growth on the fiber and the adsorption performance is poor.

[0135] Comparative Example 7

[0136] The temperature of the in-situ growth in step (4) of Example 1 was adjusted to 120° C., and the other steps were kept consistent with Example 1, to obtain a fiber membrane prepared based on in-situ growth.

[0137] The SEM images of the obtained fiber membrane are shown in Figure 9 ,from Figure 9 It can be seen that the amount of MOF growth on the fiber has increased, but it is uneven and the adsorption performance is poor.

[0138] Comparative Example 8

[0139] A method for preparing a fiber membrane based on in-situ growth comprises the following steps:

[0140] (1) Add 0.15 g of zirconium oxychloride and 1 g of polyacrylonitrile to 10 mL of N,N-dimethylformamide, and stir and mix thoroughly at 60°C to obtain a spinning solution;

[0141] (2) The spinning solution was electrospun at a voltage of 12 kV, a push rate of 1 mL / h, a needle diameter of 0.4 mm, a receiving distance of 15 cm, a receiving roller speed of 100 rpm, an ambient temperature of 30° C., and a relative humidity of 40%.

[0142] The results showed that adding zirconium oxychloride to the spinning solution could not cause uniform spinning and thus could not form a fiber membrane.

[0143] Comparative Example 9

[0144] The “0.5 g 2-aminoterephthalic acid” in step (4) of Example 1 was adjusted to “1.0 g 2-aminoterephthalic acid”, and the other steps remained the same as in Example 1 to obtain a fiber membrane prepared based on in situ growth.

[0145] The results showed that excessive MOF growth on the fiber caused agglomeration and poor adsorption performance.

[0146] Comparative Example 10

[0147] The addition of "0.5 g of 2-aminoterephthalic acid" in step (4) of Example 1 was omitted, and the other steps were kept consistent with Example 1 to obtain a fiber membrane prepared based on in situ growth.

[0148] The results showed that there was too little MOF growth on the fiber and the adsorption performance was poor.

[0149] Example 4

[0150] A method for preparing a fiber membrane based on in-situ growth comprises the following steps:

[0151] (1) Add 0.15 g of 2-aminoterephthalic acid and 1 g of polyacrylonitrile to 10 mL of N,N-dimethylformamide, and stir and mix thoroughly at 60°C to obtain a spinning solution;

[0152] (2) The spinning solution was electrospun at a voltage of 12 kV, a push injection rate of 1 mL / h, a needle diameter of 0.4 mm, a receiving distance of 15 cm, a receiving roller speed of 100 rpm, an ambient temperature of 30°C, and a relative humidity of 40%; the solution was placed in a vacuum oven at 80°C to dry and volatilize the solvent in the fiber, thereby obtaining a fiber membrane (BP) containing 15% by mass of 2-aminoterephthalic acid;

[0153] (3) 100 mg of the fiber membrane was placed in 100 mL of 75% ethylene glycol solution, 100 μL of ethylenediamine was added, and thermal cross-linking was performed at 130°C for 3 h. After the thermal cross-linking was completed, the membrane was washed with ethanol and deionized water three times each, and dried in a vacuum oven at 80°C to obtain the cross-linked fiber membrane (ABP).

[0154] (4) 100 mg of the cross-linked fiber membrane was placed in 100 mL of N,N-dimethylformamide, and 0.6 g of zirconium oxychloride, 0.4 g of 2-aminoterephthalic acid, and 1.0 g of benzoic acid were added to the mixture. The mixture was grown in situ in a reactor at 90 °C for 30 h to obtain a fiber membrane (UiO-66-NH2@ABP) prepared based on in situ growth.

[0155] Example 5

[0156] A method for preparing a fiber membrane based on in-situ growth comprises the following steps:

[0157] (1) Add 0.15 g of 2-aminoterephthalic acid and 1 g of polyacrylonitrile to 10 mL of N,N-dimethylformamide, and stir and mix thoroughly at 60°C to obtain a spinning solution;

[0158] (2) The spinning solution was electrospun at a voltage of 12 kV, a push injection rate of 1 mL / h, a needle diameter of 0.4 mm, a receiving distance of 15 cm, a receiving roller speed of 100 rpm, an ambient temperature of 30°C, and a relative humidity of 40%; the solution was placed in a vacuum oven at 80°C to dry and volatilize the solvent in the fiber, thereby obtaining a fiber membrane (BP) containing 15% by mass of 2-aminoterephthalic acid;

[0159] (3) 100 mg of the fiber membrane was placed in 100 mL of 75% ethylene glycol solution, 100 μL of ethylenediamine was added, and thermal cross-linking was performed at 135°C for 2 h. After the thermal cross-linking was completed, the membrane was washed with ethanol and deionized water three times each, and dried in a vacuum oven at 80°C to obtain the cross-linked fiber membrane (ABP).

[0160] (4) 100 mg of the cross-linked fiber membrane was placed in 100 mL of N,N-dimethylformamide, and 0.9 g of zirconium oxychloride, 0.8 g of 2-aminoterephthalic acid, and 1.4 g of benzoic acid were added to the mixture. The mixture was grown in situ in a reactor at 110 °C for 20 h to obtain a fiber membrane (UiO-66-NH2@ABP) prepared based on in situ growth.

[0161] The fiber membranes obtained in Examples 4 and 5 were subjected to performance tests, and the test results are as follows:

[0162] Table 2

[0163] example Adsorption capacity (mg / g) <![CDATA[Adsorption rate (10 -3 ×min -1 )]]> Example 4 133 3.7 Example 5 154 3.9

[0164] Comparative Example 11

[0165] The literature (Li W, Wang W, Sun J, et al. Hydrophobic modification of UiO-66 bynaphthyl ligand substitution for efficient toluene adsorption in a humidenvironment[J]. Microporous and Mesoporous Materials, 2021, 326: 111357-. DOI: 10.1016 / j.micromeso.2021.111357.) discloses the use of naphthalene to replace UiO-66 to achieve toluene adsorption, but under the condition of zero humidity, its toluene adsorption capacity is only 143 mg / g.

[0166] Comparative Example 12

[0167] The zirconium oxychloride in Example 1 was replaced with zirconium tetrachloride, and the other aspects remained the same as in Example 1 to obtain a fiber membrane prepared based on in-situ growth.

[0168] The results are as follows Figure 10 .from Figure 10 It can be seen that the crystal form of MOF synthesized by zirconium tetrachloride is not obvious and the generated MOF is not good.

[0169] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing a fiber membrane based on in situ growth, characterized in that: The steps include: (1) adding 2-aminoterephthalic acid and polyacrylonitrile to a solvent and mixing them uniformly to obtain a spinning solution; wherein the mass ratio of 2-aminoterephthalic acid to polyacrylonitrile is 0.10-0.20:1; (2) electrospinning the spinning solution and drying it to obtain a fiber membrane; (3) placing the fiber membrane in an alcohol solution, adding ethylenediamine, and performing thermal crosslinking; after the thermal crosslinking is completed, washing and drying to obtain a crosslinked fiber membrane; (4) placing the cross-linked fiber membrane in a solvent, adding zirconium oxychloride, 2-aminoterephthalic acid, and benzoic acid, and performing in situ growth to obtain a fiber membrane prepared based on in situ growth; wherein the in situ growth is in situ growth at 90-110° C. for 20-30 hours.

2. The method according to claim 1, characterized in that In step (1), the ratio of solvent to polyacrylonitrile is 8-12 mL: 1 g.

3. The method according to claim 1, characterized in that The parameters of electrospinning in step (2) are: The voltage is 10-15 kV, the injection speed is 0.2-2 mL / h, the needle diameter is 0.2-1 mm, the receiving distance is 10-20 cm, the receiving roller speed is 60-240 rpm, the ambient temperature is 25-40 ° C, and the relative humidity is 15-60%.

4. The method according to claim 1, wherein The thermal crosslinking in step (3) is carried out at 130-140° C. for 1-3 hours.

5. The method according to claim 1, characterized in that The mass ratio of the cross-linked fiber membrane, zirconium oxychloride, 2-aminoterephthalic acid, and benzoic acid in step (4) is 0.1:0.5-1.0:0.3-0.7:1-1.

5.

6. A fiber membrane prepared by in situ growth according to any one of claims 1 to 5.

7. Application of the fiber membrane prepared based on in-situ growth as claimed in claim 6 in the field of environmental pollution.

8. A toluene adsorbent, characterized in that The fiber membrane prepared based on in-situ growth as described in claim 6 is used.

9. A method for improving the toluene adsorption performance of MOF in polymers, characterized in that: The fiber membrane prepared based on in-situ growth as described in claim 6 is used.

10. A method for improving the toluene adsorption performance of polyacrylonitrile fiber membrane, characterized in that: The fiber membrane prepared based on in-situ growth as described in claim 6 is used.

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