Preparation method and application of nanometer iron polyacrylonitrile composite nanofiber felt

Abstract

A method for preparing and applying nano-iron polyacrylonitrile composite nanofiber mat is disclosed, relating to the field of dyeing and printing wastewater treatment. The preparation method includes the following steps: adding polyacrylonitrile to N,N-dimethylformamide and stirring to dissolve it to obtain a polyacrylonitrile solution; adding FeCl3 to the polyacrylonitrile solution and ultrasonically dispersing it uniformly to obtain a mixed solution; stirring the mixed solution at room temperature until it is fully mixed to obtain an electrospinning precursor solution; electrospinning the electrospinning precursor solution to obtain a polyacrylonitrile composite nanofiber mat loaded with ferric iron; and in-situ reducing the ferric iron-loaded polyacrylonitrile composite nanofiber mat to obtain nano-iron polyacrylonitrile composite nanofiber mat. This composite material is applied to the catalytic degradation of dyeing and printing wastewater, and can efficiently purify complex dye wastewater. Its composite catalyst has high reactivity, is easy to recover and reuse, and has broad development prospects.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation and catalytic degradation of dyeing and printing wastewater, specifically a method for preparing and applying nano-iron polyacrylonitrile composite nanofiber felt. Background Technology

[0002] In the existing technology, textile industrial dyeing wastewater is dark in color and opaque, containing a variety of organic pollutants such as benzene series compounds, lipids, alkanes and alcohols (accounting for 65.3%) and heavy metal ions. In addition, the dyeing wastewater itself has a high salt content and is characterized by high alkalinity and poor biodegradability. Therefore, dyeing wastewater not only poisons aquatic organic organisms, but also poses a serious threat to human life and health.

[0003] Currently, textile mills mainly use the flocculation-coagulation method to treat dyeing and printing wastewater because it has low investment costs, is easy to operate, and is suitable for treating large quantities of dyeing and printing wastewater. However, this treatment method has certain drawbacks. It generates a large amount of sludge during the treatment process, causing secondary pollution, and it is also difficult to effectively treat cationic dyes such as methylene blue.

[0004] Among various transition metal catalysts, nano-iron stands out due to its excellent catalytic activity, superior conductivity, and high stability. More importantly, it also boasts high return on investment and eco-friendliness. Furthermore, supported nano-iron composite catalysts effectively alleviate the agglomeration problem of nano-iron particles during preparation and catalysis, while also facilitating recycling. Therefore, researching a preparation method and application of nano-iron polyacrylonitrile composite nanofiber mats is of paramount importance. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a method for preparing and applying a nano-iron polyacrylonitrile composite nanofiber felt. The method involves loading trivalent iron onto polyacrylonitrile nanofibers via electrospinning and then preparing the composite material using an in-situ reduction method. The raw materials are simple and the cost is low. The nano-iron polyacrylonitrile composite nanofiber felt serves as a catalyst to achieve efficient conversion of dyeing and printing wastewater. Furthermore, the catalyst is easy to recover and exhibits good stability.

[0006] To achieve the above-mentioned objective, the present invention provides a method for preparing a nano-iron polyacrylonitrile composite nanofiber felt, comprising the following steps: (1) Add polyacrylonitrile to N,N-dimethylformamide and stir to dissolve to obtain a polyacrylonitrile solution; (2) Add FeCl3 to the polyacrylonitrile solution obtained in step (1) and disperse it evenly by ultrasonication to obtain a mixed solution; (3) Stir the mixed solution obtained in step (2) at room temperature until the solution is fully mixed and homogeneous to obtain an electrospinning precursor solution; (4) Electrospin the electrospinning precursor solution obtained in step (3) to obtain polyacrylonitrile composite nanofiber felt loaded with ferric iron. (5) The polyacrylonitrile composite nanofiber felt loaded with ferric iron obtained in step (4) is reduced in situ to obtain nano-iron polyacrylonitrile composite nanofiber felt.

[0007] Furthermore, in step (1), the weight percentage of polyacrylonitrile and N,N-dimethylformamide is 12%, and the molecular weight of polyacrylonitrile is 50,000.

[0008] Furthermore, the stirring in step (1) is carried out at 20℃~30℃ for 12 hours, and the stirring speed is 700~800rpm.

[0009] Furthermore, in step (2), the weight percentage of FeCl3 and polyacrylonitrile is 5%.

[0010] Furthermore, in step (2), the ultrasonic dispersion power is 20 kHz to 25 kHz and the time is 0.5 hours.

[0011] Furthermore, the stirring in step (3) is carried out at 20℃~30℃ for 24 hours, and the stirring speed is 700~800rpm.

[0012] Furthermore, the conditions for electrospinning in step (4) are as follows: the flow rate of the micro-injection pump is set to 0.5-1 mL / h, the voltage is 25-30 kV, the distance between the needle and the receiver is 15-20 cm, and the spinning time is 8 h.

[0013] Furthermore, the in-situ reduction conditions in step (5) are as follows: sodium borohydride (5 mol / L) is added dropwise to the polyacrylonitrile nanofiber mat loaded with ferric iron.

[0014] Application of a polyacrylonitrile nanofiber felt composite material loaded with nano-iron, wherein the nano-iron polyacrylonitrile nanofiber felt is used as a catalyst for the degradation of dyeing and printing wastewater at room temperature.

[0015] Compared with the prior art, the beneficial effects of the present invention are: ①This invention prepares nano-iron polyacrylonitrile composite nanofiber felt (Fe NP@PAN) by electrospinning. The entire preparation system is low in cost, has good catalytic activity, and is readily available and easily recyclable.

[0016] ②The preparation process of this invention is simple, the raw materials are renewable, the reaction conditions are mild, and the reaction system is green, safe and environmentally friendly.

[0017] ③ The nano-iron polyacrylonitrile composite nanofiber felt (Fe NP@PAN) obtained by this invention has a high specific surface area and porosity, and exhibits high catalytic activity in the degradation of dyeing and printing wastewater.

[0018] ④ The composite material is applied to the catalytic degradation of dyeing and printing wastewater, which can efficiently purify complex dye waste liquid. The composite material catalyst has the characteristics of high reactivity, convenient recovery and reuse, and has broad development prospects. Attached Figure Description

[0019] Figure 1 (a) is a scanning electron microscope image of the nano-iron polyacrylonitrile composite nanofiber felt of the present invention, with a magnification of 8000x and a scale bar of 10 μm.

[0020] Figure 1 (b) is a scanning electron microscope image of the nano-iron polyacrylonitrile composite nanofiber felt of the present invention after degradation of methylene blue, with a magnification of 8000x and a scale bar of 10 μm.

[0021] Figure 2 The images show the UV-Vis absorption spectra of the nano-iron polyacrylonitrile composite nanofiber felt after degrading methylene blue, and methylene blue sample photos at different time periods. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should also be noted that, to avoid obscuring the invention with unnecessary details, only structures and / or processing steps closely related to the solutions of this invention are shown in the drawings, while other details not closely related to this invention are omitted.

[0023] This invention discloses a method for preparing a nano-iron polyacrylonitrile composite nanofiber felt, comprising the following steps: (1) Add polyacrylonitrile to N,N-dimethylformamide and stir to dissolve to obtain a polyacrylonitrile solution; (2) Add FeCl3 to the polyacrylonitrile solution obtained in step (1) and disperse it evenly by ultrasonication to obtain a mixed solution; (3) Stir the mixed solution obtained in step (2) at room temperature until the solution is fully mixed and homogeneous to obtain an electrospinning precursor solution; (4) Electrospin the electrospinning precursor solution obtained in step (3) to obtain polyacrylonitrile composite nanofiber felt loaded with ferric iron. (5) The polyacrylonitrile composite nanofiber felt loaded with ferric iron obtained in step (4) is reduced in situ to obtain nano-iron polyacrylonitrile composite nanofiber felt.

[0024] Preferably, in step (1), the weight percentage of polyacrylonitrile and N,N-dimethylformamide is 12%, and the molecular weight of polyacrylonitrile is 50,000.

[0025] Preferably, the stirring in step (1) is carried out at 20℃~30℃ for 12 hours and the stirring speed is 700~800rpm.

[0026] Preferably, in step (2), the weight percentage of FeCl3 and polyacrylonitrile is 5%.

[0027] Preferably, the ultrasonic dispersion power in step (2) is 20 kHz to 25 kHz, and the time is 0.5 hours.

[0028] Preferably, the stirring in step (3) is carried out at 20℃~30℃ for 24 hours and the stirring speed is 700~800rpm.

[0029] Preferably, the conditions for electrospinning in step (4) are: the flow rate of the micro-injection pump is set to 0.5-1 mL / h, the voltage is 25-30 kV, the distance between the needle and the receiver is 15-20 cm, and the spinning time is 8 h.

[0030] Preferably, the in-situ reduction conditions in step (5) are: adding sodium borohydride (5 mol / L) dropwise to the polyacrylonitrile nanofiber mat loaded with ferric iron.

[0031] Application of a polyacrylonitrile nanofiber felt composite material loaded with nano-iron, wherein the nano-iron polyacrylonitrile nanofiber felt is used as a catalyst for the degradation of dyeing and printing wastewater at room temperature.

[0032] The present invention will be further described below with reference to the embodiments. Example 1

[0033] 23 g of polyacrylonitrile powder and 2 g of ferric chloride were weighed using an electronic analytical balance and dissolved in 40 mL of N,N-dimethylformamide. The solution was stirred at room temperature until completely dissolved, yielding a 20% polyacrylonitrile solution. The spinning solution was added to a 10 mL syringe for electrospinning. The syringe pump was set to a feed rate of 0.2 mL / h, and a voltage of 25 kV was applied. A grounded aluminum foil was used to collect the fibers at a distance of 20 cm from the needle tip. After 8 hours, a disordered nanofiber mat with an average diameter of 600 nm was formed on the aluminum foil. Figure 1 As shown in (a), the magnification is 8000x and the scale bar is 10 μm. Example 2

[0034] 13 g of polyacrylonitrile powder and 2 g of ferric chloride were weighed using an electronic analytical balance and dissolved in 40 mL of N,N-dimethylformamide. The solution was stirred at room temperature until completely dissolved, yielding a 10% polyacrylonitrile solution. The spinning solution was added to a 10 mL syringe for electrospinning. The syringe pump was set to a feed rate of 0.3 mL / h and a voltage of 30 kV was applied. A grounded aluminum foil was used to collect the fibers at a distance of 10 cm from the needle tip. After 8 hours, a disordered nanofiber mat with an average diameter of 400 nm was formed on the aluminum foil. Example 3

[0035] 0.02 g of nano-iron polyacrylonitrile composite nanofiber felt was weighed using an electronic analytical balance and placed in 30 mL of methylene blue solution with a concentration of 30 mg / L. 1 mL of the liquid was taken every 20 min, and the absorbance of the methylene blue in the sampled solution was measured using a UV-Vis spectrophotometer. The change in methylene blue absorbance indirectly represented the methylene blue concentration. Figure 2 The methylene blue absorbance decreased from 0.55 to 0 within 40 minutes, indicating that the prepared nano-iron polyacrylonitrile composite nanofiber felt completely degraded the methylene blue.

[0036] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a nano-iron polyacrylonitrile composite nanofiber felt, characterized in that: Includes the following steps: (1) Add polyacrylonitrile to N,N-dimethylformamide and stir to dissolve to obtain a polyacrylonitrile solution; (2) Add FeCl3 to the polyacrylonitrile solution obtained in step (1) and disperse it evenly by ultrasonication to obtain a mixed solution; (3) Stir the mixed solution obtained in step (2) at room temperature until the solution is fully mixed and homogeneous to obtain an electrospinning precursor solution; (4) Electrospin the electrospinning precursor solution obtained in step (3) to obtain polyacrylonitrile composite nanofiber felt loaded with ferric iron. (5) The polyacrylonitrile composite nanofiber felt loaded with ferric iron obtained in step (4) is reduced in situ to obtain nano-iron polyacrylonitrile composite nanofiber felt.

2. The method for preparing a nano-iron polyacrylonitrile composite nanofiber felt according to claim 1, characterized in that: In step (1), the weight percentage of polyacrylonitrile and N,N-dimethylformamide is 12%, and the molecular weight of polyacrylonitrile is 50,000.

3. The method for preparing a nano-iron polyacrylonitrile composite nanofiber felt according to claim 1, characterized in that: The stirring in step (1) is carried out at 20℃~30℃ for 12 hours, and the stirring speed is 700~800rpm.

4. The method for preparing a nano-iron polyacrylonitrile composite nanofiber felt according to claim 1, characterized in that: In step (2), the weight percentage of FeCl3 and polyacrylonitrile is 5%.

5. The method for preparing a nano-iron polyacrylonitrile composite nanofiber felt according to claim 1, characterized in that: In step (2), the ultrasonic dispersion power is 20 kHz to 25 kHz and the time is 0.5 hours.

6. The method for preparing a nano-iron polyacrylonitrile composite nanofiber felt according to claim 1, characterized in that: The stirring in step (3) is carried out at 20℃~30℃ for 24 hours, and the stirring speed is 700~800rpm.

7. The method for preparing a nano-iron polyacrylonitrile composite nanofiber felt according to claim 1, characterized in that: Step (4) The conditions for electrospinning are: the flow rate of the micro-injection pump is set to 0.5-1 mL / h, the voltage is 25-30 kV, the distance between the needle and the receiver is 15-20 cm, and the spinning time is 8 h.

8. The method for preparing a nano-iron polyacrylonitrile composite nanofiber felt according to claim 1, characterized in that: The conditions for in-situ reduction in step (5) are: add sodium borohydride (5 mol / L) dropwise to the polyacrylonitrile nanofiber mat loaded with ferric iron.

9. An application of a nano-iron polyacrylonitrile composite nanofiber felt, characterized in that, The nano-iron polyacrylonitrile nanofiber felt is used as a catalyst for the degradation of dyeing and printing wastewater at room temperature.

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