Electrostatic spinning fiber membrane and preparation method thereof

Abstract

The invention relates to the technical field of water treatment, in particular to an electrostatic spinning fiber membrane and a preparation method thereof.The preparation method comprises the following steps that nitrobacteria fermentation liquor, a polymer precursor, a surfactant and a cross-linking agent are dissolved in deionized water to prepare a spinning solution, and the spinning solution is subjected to electrostatic spinning; performing electrostatic spinning on the spinning solution to obtain an electrostatic spinning fiber membrane precursor; according to the preparation method of the electrostatic spinning fiber membrane provided by the invention, the porous carrier fiber membrane of cascade nitration gene engineering bacteria is prepared by utilizing in-situ electrostatic spinning; in the electrostatic spinning process, in-situ cascading of the nitrifying bacteria is facilitated, the binding force of the nitrifying bacteria and the porous carrier fiber membrane is improved, and when the electrostatic spinning membrane is applied to treatment of ammonia nitrogen pollutants in a river water body environment, the activity of the nitrifying bacteria can be prevented from being rapidly reduced in the river water treatment process, and the river sewage treatment effect is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and particularly to an electrospun fiber membrane and a preparation method thereof. Background Art

[0002] With the growth of the global population and the acceleration of the urbanization process, a large amount of sewage generated during the process of industrial wastewater, domestic sewage, agricultural non-point source pollution, and garbage dumping may pollute the water quality of rivers, endanger the survival of aquatic organisms, and further affect human health through the food chain effect. There are various methods for river water treatment, usually including physical, chemical, and biological treatment methods. Nitrifying bacteria are a common type of aerobic bacteria, including nitrite bacteria and nitrate bacteria, which play an important role in the purification process of river water quality. The nitrification conversion of ammonia nitrogen helps to maintain the balance of nitrogen elements in the river ecosystem. This provides a relatively stable living environment for other microorganisms, aquatic plants, and animals, and promotes the stable and healthy development of the entire river ecosystem. For example, aquatic plants can absorb the nitrates produced by the conversion of nitrifying bacteria as nutrients, and aquatic animals feed on aquatic plants, forming a benign ecological cycle. However, how to use nitrifying bacteria for river pollution treatment is the current focus of discussion. Common methods for immobilizing nitrifying bacteria include the biofilm method, activated sludge method, etc. In the process of river water treatment using these traditional methods for immobilizing nitrifying bacteria, over time, the biofilm will gradually age, and the activity of nitrifying bacteria will decrease with the aging of the biofilm, resulting in an unsatisfactory water treatment effect. It is necessary to regularly maintain and update the biofilm to ensure the normal metabolism of nitrifying bacteria and further maintain river treatment.

[0003] Therefore, developing a suitable carrier for nitrifying genetically engineered bacteria is an urgent problem to be solved in current river treatment. Summary of the Invention

[0004] In order to solve the problem of the relatively rapid decline in the activity of nitrifying bacteria during the river water treatment in the prior art, the present invention provides a preparation method of an electrospun fiber membrane. In this preparation method, during the electrospinning process, nitrifying bacteria are cascaded in situ to further improve the binding force between the nitrifying bacteria and the porous carrier fiber membrane, slow down the decline rate of the activity of nitrifying bacteria, and solve the problem of the relatively rapid decline in the activity of nitrifying bacteria during the river water treatment in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problems is: A method for preparing an electrospun fiber membrane includes the following steps: dissolving a nitrifying bacteria fermentation broth, a polymer precursor, a surfactant, and a crosslinking agent in deionized water to prepare a spinning solution, obtaining an electrospun fiber membrane precursor by electrospinning the spinning solution, and then subjecting the electrospun fiber membrane precursor to heat treatment at 50-60 °C for crosslinking to obtain an electrospun fiber membrane.

[0006] Optionally, the polymer precursor is a water-soluble polymer precursor.

[0007] Optionally, the polymer precursor is selected from at least one of polyvinyl alcohol, poly(lactic-co-glycolic acid), polyacrylic acid, polyethylene glycol, carboxymethyl cellulose nanocrystals, hydroxyethyl cellulose, sodium alginate, chitosan, and silk fibroin.

[0008] Optionally, the surfactant includes an anionic surfactant and an amphoteric surfactant.

[0009] Optionally, the anionic surfactant is selected from at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, monoalkyl phosphate salts, and dialkyl phosphate salts.

[0010] Optionally, the amphoteric surfactant is an amino acid-based surfactant.

[0011] Optionally, the mass ratio of the anionic surfactant to the amphoteric surfactant is 1:(1-5).

[0012] Optionally, the crosslinking agent is selected from at least one of N,N'-methylenebisacrylamide and divinyl sulfone.

[0013] Optionally, the mass ratio of the nitrifying bacteria fermentation broth, the polymer precursor, the surfactant, the crosslinking agent, and the deionized water is (1~2):(0.8~1.5):(0.5~2):(1~2):(95~100).

[0014] Another object of the present invention is to provide an electrospun fiber membrane prepared by the method for preparing an electrospun fiber membrane as described above.

[0015] The beneficial effects of the present invention are: The method for preparing an electrospun fiber membrane provided by the present invention uses in-situ electrospinning to prepare a porous carrier fiber membrane of a cascade nitrifying genetically engineered bacterium; by in-situ cascading nitrifying bacteria during the electrospinning process, it helps to improve the binding force between the nitrifying bacteria and the porous carrier fiber membrane, and when applied to the treatment of ammonia nitrogen pollutants in the river water environment, it can avoid the rapid decline in the activity of nitrifying bacteria during the river water treatment process, effectively improving the effect of river water treatment. Description of the Drawings

[0016] The present invention will be further described below in conjunction with the drawings and embodiments.

[0017] Figure 1 It is a scanning electron microscope picture of the electrospun fiber membrane prepared in Example 1 of the present invention; Figure 2 It is a scanning electron microscope picture of the electrospun fiber membrane prepared in Example 2 of the present invention. Detailed Description of the Invention

[0018] The present invention will now be described in further detail. The embodiments described below are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0019] To solve the problem that the activity of nitrifying bacteria decreases rapidly during the treatment of river water in the prior art, the present invention provides a method for preparing an electrospun fiber membrane, which comprises the following steps: dissolving a nitrifying bacteria fermentation broth, a polymer precursor, a surfactant, and a crosslinking agent in deionized water to prepare a spinning solution, subjecting the spinning solution to electrospinning to obtain an electrospun fiber membrane precursor, and then subjecting the electrospun fiber membrane precursor to heat treatment at 50-60 °C for crosslinking, preferably for 2-3 h, to obtain an electrospun fiber membrane.

[0020] The nitrifying bacteria fermentation broth is a bacterial solution obtained by fermenting nitrifying bacteria, and its concentration is 1.0-2.0 wt%. Preferably, the nitrifying bacteria fermentation broth is selected from at least one of a nitrite bacteria fermentation broth and a nitrate bacteria fermentation broth, and further preferably, the nitrifying bacteria fermentation broth in the present invention is from Probiotech (Shanghai) Co., Ltd., and its main components are Nitrosomonas and Nitrobacter.

[0021] To balance the water treatment effect of the fiber membrane and the mechanical properties of the fiber membrane, the present invention preferably performs electrospinning as follows: Subjecting the spinning solution to electrospinning at a voltage of 15.0-20.0 kV to obtain a porous carrier fiber membrane of in-situ electrospun cascade nitrifying genetically engineered bacteria, that is, an electrospun fiber membrane. The process parameters of the electrospinning are as follows: the flow rate of the spinning solution is 0.06-0.20 mL / min, the applied voltage is 15.0-20.0 kV, and the distance between the roller and the needle tip is 15-17 cm.

[0022] The preparation method of the electrospun fiber membrane provided by the present invention uses in-situ electrospinning to prepare a porous carrier fiber membrane with cascaded nitrifying genetically engineered bacteria. By cascading nitrifying bacteria in-situ during the electrospinning process, it helps to improve the binding force between the nitrifying bacteria and the porous carrier fiber membrane. When applied to the treatment of ammonia nitrogen pollutants in river water environment, it can avoid the rapid decline of the activity of nitrifying bacteria during the river water treatment process, and effectively improve the effect of river water treatment.

[0023] To further improve the binding force between the nitrifying bacteria and the porous carrier fiber membrane, the present invention preferably uses a water-soluble polymer precursor as the polymer precursor. This water-soluble polymer precursor can be a synthetic polymer or a natural polymer. Specifically, the present invention preferably selects the polymer precursor from at least one of polyvinyl alcohol (PVA), poly(lactic-co-glycolic acid) (PLGA), polyacrylic acid (PAA), polyethylene glycol (PEG), carboxymethyl cellulose nanocrystals, hydroxyethyl cellulose, sodium alginate, chitosan, and silk fibroin.

[0024] By using a water-soluble polymer precursor in the present invention, the surface of the prepared fiber membrane contains abundant hydrophilic groups such as carboxyl and amide, which have strong binding force with the carboxyl, amino, hydroxyl, and phosphate groups on the surface of nitrifying bacteria. After cross-linking of this special in-situ electrospun porous carrier fiber membrane with cascaded nitrifying genetically engineered bacteria, the nitrifying bacteria can be further locked on the fiber membrane, and the ammonia nitrogen pollutants in the water body can be adsorbed by the swelling of the fiber membrane to achieve the treatment of pollutants, further improving the water treatment effect.

[0025] To enhance the dispersion performance of nitrifying bacteria in the porous carrier fiber membrane and improve the mechanical properties of the porous carrier fiber membrane, the present invention preferably uses surfactants including anionic surfactants and zwitterionic surfactants. By combining anionic surfactants and zwitterionic surfactants, the dispersion performance of nitrifying bacteria in the porous carrier fiber membrane can be synergistically enhanced and the mechanical properties of the porous carrier fiber membrane can be improved.

[0026] Specifically, the present invention preferably selects at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, monoalkyl phosphate salt, and dialkyl phosphate salt as the anionic surfactant; the zwitterionic surfactant is an amino acid type surfactant, and further preferably selects at least one of dodecylaminopropionic acid, sodium myristoyl glutamate, and sodium lauroyl glutamate as the zwitterionic surfactant.

[0027] Furthermore, the present invention preferably uses a mass ratio of the anionic surfactant to the zwitterionic surfactant of 1:(1 - 5).

[0028] The present invention preferably selects at least one of N,N'-methylenebisacrylamide and divinyl sulfone as the cross-linking agent.

[0029] In order to take into account both the water treatment effect and the mechanical properties of the electrospun fiber membrane, the present invention preferably has a mass ratio of nitrifying bacteria fermentation broth, polymer precursor, surfactant, cross-linking agent and deionized water in the spinning solution of (1~2): (0.8~1.5): (0.5~2): (1~2): (95~100).

[0030] In the process of river water treatment, the traditional method of fixing nitrifying bacteria will gradually age over time, and the activity of nitrifying bacteria will decrease with the aging of the biofilm, resulting in unsatisfactory water treatment effect. The biofilm needs to be regularly maintained and updated to ensure the normal metabolism of nitrifying bacteria and further maintain river treatment. The scheme provided by the present invention is to prepare a porous carrier fiber membrane by in-situ electrospinning cascade nitrifying genetic engineering bacteria; the electrospinning process is adopted, and the in-situ cascade nitrifying genetic engineering bacteria are applied to the treatment of ammonia nitrogen compounds in river water, which can effectively convert ammonia nitrogen organic matter in the river into nitrite, and further into nitrate, thereby reducing the concentration of ammonia nitrogen in the water, reducing the toxicity to aquatic organisms, thereby improving the water environment and promoting the stability of the ecosystem.

[0031] The electrospun fiber membrane provided by the present invention can be used to treat ammonia nitrogen pollutants in water environments. The porous carrier fiber membrane of the cascade nitrifying genetically engineered bacteria provided by the present invention can effectively reduce the loss of microorganisms and ensure the activity of the nitrifying genetically engineered bacteria. This cascade structure can also effectively avoid the loss of nitrifying genetically engineered bacteria from the porous carrier fiber membrane, thereby reducing the decomposition efficiency of ammonia nitrogen pollutants.

[0032] Another object of the present invention is to provide an electrospun fiber membrane, which is prepared by the electrospun fiber membrane preparation method as described above.

[0033] The electrospun fiber membrane provided by the present invention utilizes in-situ electrospinning during the preparation process to obtain a porous carrier fiber membrane of cascade nitrifying genetically engineered bacteria; by in-situ cascading nitrifying bacteria during the electrospinning process, it is helpful to improve the binding force between the nitrifying bacteria and the porous carrier fiber membrane, and is applied to the treatment of ammonia nitrogen pollutants in river water environments, which can avoid the rapid decrease in the activity of nitrifying bacteria during river water treatment and effectively improve the effect of river sewage treatment.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0035] Example 1 This embodiment provides a method for preparing an electrospun fiber membrane, comprising the following steps: By weight parts, 1 part by weight of nitrifying bacteria fermentation broth (concentration: 1.5 wt%), 0.8 part by weight of polyvinyl alcohol, 0.5 part by weight of sodium dodecylbenzenesulfonate, 0.5 part by weight of dodecyl aminopropionic acid, and 1.0 part by weight of N,N'-methylenebisacrylamide are dissolved in 95 parts by weight of deionized water to prepare a spinning solution; the spinning solution is electrospun at a voltage of 20.0 kV to obtain a porous carrier fiber membrane precursor of in-situ electrospun cascade nitrifying genetically engineered bacteria, namely the electrospun fiber membrane precursor, and then the electrospun fiber membrane precursor is heat-treated at 55 °C for 2.5 h for crosslinking to obtain an electrospun fiber membrane, and its scanning electron micrograph is shown in Figure 1 as shown. The process parameters of electrospinning are: the flow rate of the spinning solution is 0.10 mL / min, the applied voltage is 20.0 kV, and the distance between the roller and the needle tip is 16 cm.

[0036] Example 2 This example provides a method for preparing an electrospun fiber membrane, which includes the following steps: By weight parts, 1.5 parts by weight of nitrifying bacteria fermentation broth (concentration: 1.0 wt%), 1.0 part by weight of PLGA, 0.5 part by weight of sodium dodecyl sulfate, 1.0 part by weight of sodium myristoyl glutamate, and 1.5 parts by weight of divinyl sulfone are dissolved in 98 parts by weight of deionized water to prepare a spinning solution; the spinning solution is electrospun at a voltage of 20.0 kV to obtain a porous carrier fiber membrane precursor of in-situ electrospun cascade nitrifying genetically engineered bacteria, namely the electrospun fiber membrane precursor, and then the electrospun fiber membrane precursor is heat-treated at 55 °C for 2.5 h for crosslinking to obtain an electrospun fiber membrane, and its scanning electron micrograph is shown in Figure 2 as shown. The process parameters of electrospinning are: the flow rate of the spinning solution is 0.10 mL / min, the applied voltage is 20.0 kV, and the distance between the roller and the needle tip is 16 cm.

[0037] Example 3 This example provides a method for preparing an electrospun fiber membrane, which includes the following steps: By weight, 2.0 parts by weight of nitrifying bacteria fermentation broth (concentration: 2.0 wt%), 1.5 parts by weight of sodium alginate, 1.0 part by weight of dialkyl phosphate, 1.0 part by weight of sodium myristoyl glutamate, and 2.0 parts by weight of N,N'-methylenebisacrylamide are dissolved in 100 parts by weight of deionized water to prepare a spinning solution; the spinning solution is electrospun at a voltage of 20.0 kV to obtain a porous carrier fiber membrane precursor of in-situ electrospun cascade nitrifying genetically engineered bacteria, that is, an electrospun fiber membrane precursor, and then the electrospun fiber membrane precursor is heat-treated at 55 °C for 2.5 h for crosslinking to obtain an electrospun fiber membrane. The process parameters of electrospinning are as follows: the flow rate of the spinning solution is 0.10 mL / min, the applied voltage is 20.0 kV, and the distance between the roller and the needle tip is 16 cm.

[0038] Comparative Example 1 This comparative example provides a method for preparing an electrospun fiber membrane, which includes the following steps: By weight, 0.8 part by weight of polyvinyl alcohol, 0.5 part by weight of sodium dodecylbenzenesulfonate, 0.5 part by weight of dodecylaminopropionic acid, and 1.0 part by weight of N,N'-methylenebisacrylamide are dissolved in 95 parts by weight of deionized water to prepare a spinning solution; the spinning solution is electrospun at a voltage of 20.0 kV to obtain a porous carrier fiber membrane precursor of in-situ electrospun cascade nitrifying genetically engineered bacteria, that is, an electrospun fiber membrane precursor, and then the electrospun fiber membrane precursor is heat-treated at 55 °C for 2.5 h for crosslinking to obtain an electrospun fiber membrane. The process parameters of electrospinning are as follows: the flow rate of the spinning solution is 0.10 mL / min, the applied voltage is 20.0 kV, and the distance between the roller and the needle tip is 16 cm.

[0039] Comparative Example 2 This comparative example provides a method for preparing an electrospun fiber membrane, which includes the following steps: By weight, 0.8 part by weight of polyvinyl alcohol, 0.5 part by weight of sodium dodecylbenzenesulfonate, 0.5 part by weight of dodecylaminopropionic acid, and 1.0 part by weight of N,N'-methylenebisacrylamide are dissolved in 95 parts by weight of deionized water to prepare a spinning solution; the spinning solution is electrospun at a voltage of 20.0 kV to obtain a porous carrier fiber membrane precursor of in-situ electrospun cascade nitrifying genetically engineered bacteria, that is, an electrospun fiber membrane precursor, and then the electrospun fiber membrane precursor is heat-treated at 55 °C for 2.5 h for crosslinking to obtain an electrospun fiber membrane. The process parameters of electrospinning are as follows: the flow rate of the spinning solution is 0.10 mL / min, the applied voltage is 20.0 kV, and the distance between the roller and the needle tip is 16 cm.

[0040] The prepared porous carrier fiber membrane was immersed in a nitrifying bacteria fermentation broth (concentration: 1.5 wt%) for 2 h to obtain an electrospun fiber membrane.

[0041] Comparative Example 3 This comparative example provides a method for preparing an electrospun fiber membrane, which includes the following steps: By weight, 1 part by weight of nitrifying bacteria fermentation broth (concentration: 1.5 wt%), 0.8 part by weight of polyvinyl alcohol, 1.0 part by weight of sodium dodecylbenzenesulfonate, and 1.0 part by weight of N,N'-methylenebisacrylamide were dissolved in 95 parts by weight of deionized water to prepare a spinning solution; the spinning solution was electrospun at a voltage of 20.0 kV to obtain a porous carrier fiber membrane precursor of in-situ electrospun cascade nitrifying genetically engineered bacteria, i.e., an electrospun fiber membrane precursor, and then the electrospun fiber membrane precursor was heat-treated at 55 °C for 2.5 h for crosslinking to obtain an electrospun fiber membrane. The process parameters of electrospinning were as follows: the flow rate of the spinning solution was 0.10 mL / min, the applied voltage was 20.0 kV, and the distance between the roller and the needle tip was 16 cm.

[0042] Comparative Example 4 This comparative example provides a method for preparing an electrospun fiber membrane, which includes the following steps: By weight, 1 part by weight of nitrifying bacteria fermentation broth (concentration: 1.5 wt%), 0.8 part by weight of polyvinyl alcohol, 1.0 part by weight of dodecylaminopropionic acid, and 1.0 part by weight of N,N'-methylenebisacrylamide were dissolved in 95 parts by weight of deionized water to prepare a spinning solution; the spinning solution was electrospun at a voltage of 20.0 kV to obtain a porous carrier fiber membrane precursor of in-situ electrospun cascade nitrifying genetically engineered bacteria, i.e., an electrospun fiber membrane precursor, and then the electrospun fiber membrane precursor was heat-treated at 55 °C for 2.5 h for crosslinking to obtain an electrospun fiber membrane. The process parameters of electrospinning were as follows: the flow rate of the spinning solution was 0.10 mL / min, the applied voltage was 20.0 kV, and the distance between the roller and the needle tip was 16 cm.

[0043] The fiber membranes prepared in the above examples and comparative examples were subjected to performance tests, and the test methods were as follows: Test of removal rate: 0.2 g of the fiber membrane was added to 100 mL of Pb2+ solution with a concentration of C 0 , the pH was adjusted to 5, and it was adsorbed to equilibrium at room temperature. The concentration C of Pb 2+ in the solution was measured by atomic absorption spectrophotometry, and the removal rate was calculated. The calculation formula for the removal rate was Q = (C 0 - C) / C 0 × 100%.

[0044] Ammonia nitrogen wastewater degradation experiment: The test was carried out in accordance with GB 7479-87. Simulated ammonia nitrogen wastewater (concentration: 100 mg / L) and the carrier were added into the aeration bottle (the carrier dosage was 10%). At 30 °C, the aeration rate was 4 L / min, and aeration was carried out for 24 h, then samples were taken. The ammonia nitrogen concentration was analyzed by the Nessler's reagent photometric method.

[0045] Mechanical property test: The test was carried out with reference to GB / T 1440-2006. The fiber membrane was cut into splines of 50×10×3 mm, and its strength performance was tested.

[0046] The test results are shown in Table 1 and Table 2: Table 1 Removal rates of Specific Examples 1-3 and Comparative Examples 1-4 C0 (mg / L) C (mg / L) Q（%） Example 1 10 0.349 96.51 Example 2 10 0.335 96.65 Example 3 10 0.358 96.42 Comparative Example 1 10 3.305 66.95 Comparative Example 2 10 3.123 68.77 Comparative Example 3 10 2.887 71.13 Comparative Example 4 10 2.142 78.58 Table 2 Physical property analysis of Specific Examples 2-3 and Comparative Examples 1-4 Tensile strength / Mpa Elongation at break / % Ammonia nitrogen removal rate / % Example 1 7.89 85.46 98.65 Example 2 7.99 88.55 98.77 Example 3 7.87 85.44 97.52 Comparative Example 1 7.54 84.52 12.41 Comparative Example 2 7.22 84.38 56.12 Comparative Example 3 5.42 52.13 71.22 Comparative Example 4 5.78 53.88 69.54 It can be seen from the above data that the electrospun fiber membranes prepared in each example of the present invention all have excellent water treatment effects and excellent mechanical properties.

[0047] The difference between Comparative Example 1 and Example 1 is that the nitrifying bacteria fermentation broth was not added to the spinning solution, and no nitrifying bacteria fermentation broth was introduced, resulting in a significant decrease in the removal rate and ammonia nitrogen removal rate of the fiber membrane.

[0048] The difference between Comparative Example 2 and Example 1 is that the nitrifying bacteria fermentation broth was not added to the spinning solution, and nitrifying bacteria were introduced by impregnation. The nitrifying bacteria were not firmly fixed on the fiber membrane, resulting in a significant decrease in the removal rate and ammonia nitrogen removal rate of the prepared fiber membrane.

[0049] The difference between Comparative Example 3 and Example 1 is that only an anionic surfactant was added. Because only the anionic surfactant was added, the adsorption ability of the prepared fiber membrane for nitrifying bacteria decreased, and the nitrifying bacteria were unevenly dispersed on the fiber membrane, resulting in a decrease in mechanical properties and further a decrease in the removal rate and ammonia nitrogen removal rate.

[0050] The difference between Comparative Example 4 and Example 1 is that only an amphoteric ion surfactant was added. Because only the amphoteric surfactant was added, the adsorption ability of the prepared fiber membrane for nitrifying bacteria decreased, and the nitrifying bacteria were unevenly dispersed on the fiber membrane, resulting in a decrease in mechanical properties and further a decrease in the removal rate and ammonia nitrogen removal rate.

[0051] Enlightened by the above-described ideal embodiments of the present invention, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing an electrospun fiber membrane, characterized in that: The method comprises the following steps: dissolving nitrifying bacteria fermentation liquid, polymer precursor, surfactant and cross-linking agent in deionized water to prepare spinning solution, subjecting the spinning solution to electrospinning to obtain electrospinning fiber membrane precursor, and then subjecting the electrospinning fiber membrane precursor to heat treatment at 50-60°C for cross-linking to obtain electrospinning fiber membrane.

2. The method for preparing an electrospun fiber membrane according to claim 1, characterized in that: The polymer precursor is a water-soluble polymer precursor.

3. The method for preparing an electrospun fiber membrane according to claim 1, characterized in that: The polymer precursor is selected from at least one of polyvinyl alcohol, polylactic acid-glycolic acid copolymer, polyacrylic acid, polyethylene glycol, carboxymethyl cellulose nanocrystals, hydroxyethyl cellulose, sodium alginate, chitosan and silk fibroin.

4. The method for preparing an electrospun fiber membrane according to claim 1, characterized in that: The surfactant includes anionic surfactant and zwitterionic surfactant.

5. The method for preparing an electrospun fiber membrane according to claim 4, characterized in that: The anionic surfactant is selected from at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, monoalkyl phosphate salts, and dialkyl phosphate salts.

6. The method for preparing an electrospun fiber membrane according to claim 4, characterized in that: The zwitterionic surfactant is an amino acid type surfactant.

7. The method for preparing an electrospun fiber membrane according to claim 4, characterized in that: The mass ratio of the anionic surfactant to the zwitterionic surfactant is 1:(1-5).

8. The method for preparing an electrospun fiber membrane according to claim 1, characterized in that: The cross-linking agent is selected from at least one of N,N'-methylenebisacrylamide and divinyl sulfone.

9. The method for preparing an electrospun fiber membrane according to any one of claims 1 to 8, characterized in that: The mass ratio of the nitrifying bacteria fermentation broth, the polymer precursor, the surfactant, the cross-linking agent and the deionized water is (1-2): (0.8-1.5): (0.5-2): (1-2): (95-100).

10. An electrospun fiber membrane, characterized in that: The preparation is carried out by the preparation method of the electrospinning fiber membrane as described in any one of claims 1 to 9.

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