Iron carbide / biochar composite electro-fenton cathode material, preparation method and application thereof

Abstract

The application discloses a kind of ferrocarbonate / biochar composite electrofenton cathode material and its preparation method and application, the composite electrofenton cathode material (Fe3C / BC) is formed by iron-based metal organic framework material and straw mixed calcination, iron-based metal organic framework material accounts for 5% to 20% of straw mass, wherein metal iron mainly exists in the form of Fe3C.The Fe3C / BC electrofenton cathode material of the application only needs one-step hydrothermal and simple mixing grinding calcination to be prepared, the cathode material prepared can not only improve the dispersity and stability of electrofenton active site, while BC good conductivity and molecular oxygen activation capacity, can accelerate the electron transfer in system, promote the generation of active substance, thereby significantly improve the degradation effect of neonicotinoid pesticide pollutants.The electrofenton cathode material prepared by the application has excellent water matrix interference resistance and relatively wide pH and pollutant concentration application range, thus has great application value.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of electro-Fenton cathode materials, and particularly relates to a Fe3C / BC composite electro-Fenton cathode material and a preparation method and application thereof. BACKGROUND

[0002] Neonicotinoid pesticides have become the most widely used class of insecticides globally, which can be applied to agriculture through spraying and soil irrigation, and can penetrate into soil and groundwater through wind, rainwater and surface runoff, and eventually enter water bodies, seriously threatening human health and environmental safety. Notably, neonicotinoid pesticides have strong stability in the water environment and are difficult to remove through natural photolysis and hydrolysis.

[0003] A large number of studies have shown that advanced oxidation technology has significant advantages in treating water organic pollutants, and electro-Fenton technology has attracted much attention due to its green and efficient characteristics. However, the traditional homogeneous electro-Fenton technology mainly has the disadvantages of narrow pH range, easy production of iron sludge and non-recyclable catalyst. In order to overcome the shortcomings of the heterogeneous electro-Fenton technology, the heterogeneous electro-Fenton technology has gradually become a research hotspot. The cathode material is the core of the heterogeneous electro-Fenton technology, which determines the treatment effect of the target pollutants. Metal-organic framework materials have great development potential due to their high porosity, low density and large specific surface area. Notably, the skeleton part of the metal-organic framework material contains inorganic metal components, which can serve as active centers for heterogeneous electro-Fenton reactions, and thus have important application value in degrading organic pollutants. In addition, the metal-organic framework material can be converted into a magnetic derivative as an electro-Fenton cathode material under high-temperature calcination in an inert atmosphere, which is beneficial to its recovery and subsequent reuse. However, the metal-organic framework material is prone to structural collapse, the catalytic active sites are easily damaged, and agglomeration is easily occurred under high-temperature conditions, which limits the performance of the metal-organic framework material derivative. Chinese Invention Patent CN113620390B discloses a method for electro-assisted metal-organic framework material catalytic treatment of heavy metal-EDTA complex wastewater, but due to the single magnetic component, part of the agglomeration occurs, which exhibits limited pollutant removal efficiency. SUMMARY

[0004] The application provides a Fe3C / BC electro-Fenton cathode material to solve the problems in the prior art. The prepared Fe3C / BC cathode material can not only improve the dispersity and stability of the electro-Fenton active sites, but also can accelerate the electron transfer in the system and promote the generation of active substances in the system due to the good conductivity and molecular oxygen activation capacity of the BC, thereby significantly improving the degradation effect of neonicotinoid pesticides.

[0005] The application also provides a preparation method of the Fe3C / BC electro-Fenton cathode material and application thereof in electro-Fenton degradation of neonicotinoid pesticide pollutants.

[0006] Technical scheme: In order to achieve the above-mentioned purpose, the Fe3C / BC electro-Fenton cathode material is formed by mixing and calcining iron-based metal organic framework material and straw, and the iron-based metal organic framework material accounts for 5%-20% of the mass of the straw.

[0007] As preferred, the iron-based metal organic framework material accounts for 10% of the mass of the straw.

[0008] Among them, the metal iron in the Fe3C / BC electro-Fenton cathode material mainly exists in the form of Fe3C.

[0009] The preparation method of the Fe3C / BC electro-Fenton cathode material provided by the application comprises the following steps:

[0010] (1) Iron salt and diaminoterephthalic acid are added to an organic solvent for hydrothermal reaction, and after cooling, washing and drying, an iron-based metal organic framework material is obtained;

[0011] (2) The iron-based metal organic framework material obtained in step (1) and straw powder are mixed and ground, and calcination is carried out in an inert gas to obtain the Fe3C / BC electro-Fenton cathode material.

[0012] Among them, the iron source in step (1) is selected from any one or several of ferric chloride, ferric nitrate and ferric acetate.

[0013] Among them, the iron salt in step (1) is added in an amount of 8-12% g / mL of the organic solvent N,N-dimethylformamide solvent; and the diaminoterephthalic acid is added in an amount of 2-5% g / mL of the organic solvent N,N-dimethylformamide solvent.

[0014] Among them, the hydrothermal reaction in step (1) is carried out at 100-180℃ for 12-24h.

[0015] Among them, the mass ratio of the iron-based metal organic framework material to the straw in step (2) is 0.05-0.2:1.

[0016] As preferred, the straw is any one of corn, rice, wheat or sugarcane straw.

[0017] Among them, the inert gas in step (2) is nitrogen or argon; the heating rate of calcination is 5-10℃, the temperature is 500-900℃, and the calcination time is 1-5h.

[0018] The application of the Fe3C / BC electro-Fenton cathode material in the electro-Fenton degradation of pollutants.

[0019] The pollutants are nitenpyram, imidacloprid or thiamethoxam, the electro-Fenton degradation process is carried out in a three-electrode system, the three electrodes are respectively Fe3C / BC loaded carbon cloth as cathode, Pt sheet as anode, saturated calomel electrode as reference electrode, nitenpyram aqueous solution containing Na2SO4 as reaction liquid for electro-Fenton degradation experiment, the pH value of the system is 3-9, and the reaction time is 40-60 min.

[0020] As preferred, the Fe3C / BC electro-Fenton cathode material in the process of degrading nitenpyram by electro-Fenton is: a three-electrode system is used, the three electrodes are respectively Fe3C / BC loaded carbon cloth as cathode, Pt sheet as anode, saturated calomel electrode as reference electrode, the initial voltage is set to-0.5V, Na2SO4 is used as electrolyte, nitenpyram is used as pollutants for electro-Fenton degradation experiment under the condition of oxygen, the pH value of the system is adjusted to 3, and the reaction is carried out for 60 min.

[0021] The Fe3C / BC electro-Fenton cathode material is prepared by a specific preparation method, and is applied to efficient and rapid degradation of neonicotinoid pesticides. The iron-based metal organic framework material is directly mixed, ground and calcined with straw, the iron-based metal organic framework material accounts for 5%-20% of the mass of the straw, the preparation of the Fe3C / BC electro-Fenton cathode material only needs one-step hydrothermal and simple mixing, grinding and calcining, and does not need secondary hydrothermal treatment, so that the steps are simple, the cost is low, and the metal iron in the Fe3C / BC electro-Fenton cathode material mainly exists in the form of Fe3C instead of metal oxide. In addition, the biomass-based carbon is selected as the carrier in the iron-based metal organic framework material, so that the Fe3C / BC can significantly improve the performance of degrading neonicotinoid pesticides compared with the BC prepared by calcining the straw alone, and greatly reduces the metal leakage and improves the stability of the cathode material compared with the Fe3C prepared by calcining the iron-based metal organic framework material alone. The Fe3C / BC electro-Fenton cathode material prepared in the application has good stability and reusability, is strong in water matrix interference resistance, has a wide pH range, can be applied to treatment of water bodies with different concentrations of pollutants, and has fast degradation rate and good degradation effect.

[0022] Advantages: Compared with the prior art, the application has the following advantages:

[0023] (1) The Fe3C / BC electro-Fenton cathode material of the application can be prepared only by one-step hydrothermal and simple mixing, grinding and calcining, so that the process is simple and the cost is low.

[0024] (2) In the Fe3C / BC electro-Fenton cathode material prepared by the present invention, the biomass-based carbon component has strong conductivity, large specific surface area, and excellent reduction ability for molecular oxygen. Using it as a carrier can effectively reduce the agglomeration of electro-Fenton active sites, enhance the current density in the electro-Fenton system, and promote the generation of active substances, thereby significantly improving the degradation effect of neonicotinoid pesticides.

[0025] (3) The Fe3C / BC electro-Fenton cathode material prepared in the present invention has excellent resistance to water matrix interference, is applicable in a wide pH range, and can treat water bodies with different initial concentrations of pollutants, thus having great application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a scanning electron microscope image of the Fe3C / BC electro-Fenton cathode material in Example 1 of the present invention.

[0027] Figure 2 These are the X-ray diffraction patterns of the electro-Fenton cathode materials in Example 1 and Comparative Example 1 of the present invention.

[0028] Figure 3 This is a diagram showing the degradation effect of nitenpyram by the electro-Fenton cathode materials in Examples 1 to 3 of the present invention and Comparative Example 1.

[0029] Figure 4 This is a graph showing the effect of the Fe3C / BC electro-Fenton cathode material loading on the degradation effect of nitenpyram in Example 1 of the present invention.

[0030] Figure 5 This is a diagram showing the degradation effect of nitenpyram on the Fe3C / BC electro-Fenton cathode material at different pH values ​​in Example 1 of the present invention.

[0031] Figure 6 This is a diagram showing the degradation effect of the Fe3C / BC electro-Fenton cathode material on different initial concentrations of nitenpyram in Example 1 of the present invention.

[0032] Figure 7 This is a diagram showing the degradation effect of nitenpyram on the Fe3C / BC electro-Fenton cathode material at different applied potentials in Example 1 of the present invention.

[0033] Figure 8 This is a diagram showing the degradation effect of nitenpyram by the Fe3C / BC electro-Fenton cathode material in Example 1 of the present invention in different water matrices.

[0034] Figure 9 The cyclic stability of the Fe3C / BC electro-Fenton cathode material in Example 1 of the present invention in degrading nitenpyram.

[0035] Figure 10 This is a performance diagram of the Fe3C / BC electro-Fenton cathode material in Example 1 of the present invention for degrading other neonicotinoid pesticide pollutants.

[0036] Figure 11 Figure for degradation effect of electro-Fenton cathode material in Example 1 and Comparative Example 1-2 on nitenpyram.

[0037] Figure 12 Degradation effect of nitenpyram pollutants in different reaction systems.

[0038] Figure 13 Linear sweep voltammogram and electrochemical impedance spectrogram of Fe3C / BC in Example 1 and BC in Comparative Example 1. DETAILED DESCRIPTION

[0039] The experimental methods described in the examples are all conventional methods unless otherwise specified; and the reagents and materials described are all commercially available unless otherwise specified.

[0040] Example 1

[0041] A preparation method of a Fe3C / BC electro-Fenton cathode material, comprising the following steps:

[0042] (1) Preparation of metal organic framework material: 2.7 g of FeCl3·6H2O was weighed and added into 30 mL of N,N-dimethylformamide (DMF), and 0.9 g of diaminoterephthalic acid was weighed and added into 30 mL of DMF, both solutions were mixed and stirred for 1 h, then transferred into a reaction kettle with a brown polytetrafluoroethylene liner, and hydrothermally reacted at 110℃ for 24 h. After the hydrothermal reaction, the material was washed by centrifugation with ethanol for 3 times, dried in a vacuum drying oven at 60℃ overnight, and then taken out and ground for storage.

[0043] (2) The obtained metal organic framework material and corn straw powder were mixed and ground, then placed in a crucible and transferred to a tube furnace, and the mass ratio of the metal organic framework material to the corn straw was 0.1:1. High-purity argon was introduced, and the temperature was raised to 800℃ at a rate of 5℃ / min and kept for 2 h. After the tube furnace was naturally cooled, the sample was taken out, and a Fe3C / BC electro-Fenton cathode material was obtained. In this example, the metal organic framework material accounted for 10% of the mass of the corn straw.

[0044] The micro-morphology of the Fe3C / BC electro-Fenton cathode material prepared in Example 1 is shown in Figure 1 The Fe3C particles are uniformly loaded on the surface of the biochar.

[0045] Comparative Example 1

[0046] This comparative example is the same as Example 1, except that no iron-based metal organic framework material is added, and the corn straw powder is directly calcined, and the product is denoted as BC.

[0047] Comparative Example 2

[0048] The comparative example is the same as example 1, and the only difference is that corn straw powder is not added, and the iron-based metal organic framework material is directly calcined, and the product is recorded as Fe3C.

[0049] The crystal structure composition of Fe3C / BC prepared in example 1 and BC prepared in comparative example 1 is shown in Figure 2 As shown in the table, in the Fe3C / BC electro-Fenton cathode material prepared in example 1, the metal iron mainly exists in the form of Fe3C.

[0050] Example 2

[0051] The example is the same as example 1, and the only difference is that the mass ratio of the iron-based metal organic framework material to the straw is 0.05:1. The product is recorded as Fe3C / BC(0.05), and in this example, the iron-based metal organic framework material accounts for 5% of the mass of the corn straw.

[0052] Example 3

[0053] The example is the same as example 1, and the only difference is that the mass ratio of the iron-based metal organic framework material to the straw is 0.2:1. The product is recorded as Fe3C / BC(0.2), and in this example, the iron-based metal organic framework material accounts for 20% of the mass of the corn straw.

[0054] Example 4

[0055] The example is the same as example 1, and the only difference is that the hydrothermal time is 12h, and the calcination temperature is 900℃.

[0056] Example 5

[0057] The example is the same as example 1, and the only difference is that the iron salt addition amount is 12% g / mL of N,N-dimethylformamide solvent; and the diamino terephthalic acid addition amount is 5% g / mL of N,N-dimethylformamide solvent.

[0058] Test example 1

[0059] The degradation effect of the electro-Fenton cathode material prepared in examples 1-3 and comparative example 1 on nitenpyram in water was investigated, and the specific method is as follows:

[0060] (1) 6mg of the electro-Fenton cathode material prepared in examples 1-3 and comparative example 1, 300μL of anhydrous ethanol, 100μL of water, and 6μL of Nafion were added to a 1.5mL centrifuge tube, and after ultrasonic treatment for 40min, they were uniformly coated on a circular hydrophobic and air-permeable carbon cloth with a diameter of 2.9cm, and were air-dried for standby.

[0061] (2) The electro-Fenton degradation experiment is carried out in a three-electrode system in a gas diffusion electrode under the condition of oxygen flow, wherein the three electrodes are a Fe3C / BC-loaded carbon cloth as a cathode, a Pt sheet electrode as an anode, and a saturated calomel electrode as a reference electrode. The initial voltage is set to -0.5 V, and the reaction is carried out for 60 min.

[0062] (3) The electro-Fenton degradation experiment is carried out on 5 mg / L nitenpyram aqueous solution containing 0.05 M Na2SO4 with Na2SO4 solution as an electrolyte, and the change of nitenpyram concentration in the electro-Fenton degradation process is determined by a liquid chromatograph, and the result is shown in Table 2. Figure 3 As shown in Table 2, the Fe3C / BC prepared in the application can significantly improve the degradation ability of nitenpyram compared with the BC alone. Meanwhile, the mass ratio of the metal organic framework material to the straw in the cathode material prepared in the application is very important, and too high or too low of the metal organic framework material will significantly affect the degradation ability of the material to nitenpyram. The effect of the metal organic framework material accounting for 10% of the mass of the straw is the best, which is not only obviously better than the metal organic framework material accounting for 5% or 20% of the mass of the straw, but also significantly improves the degradation rate.

[0063] Test Example 2

[0064] The influence of the Fe3C / BC electro-Fenton cathode material load prepared in Example 1 of the application on the degradation performance of nitenpyram pollutants is investigated. The electro-Fenton degradation process is carried out according to the steps of Test Example 1, and the difference is only that the amount of Fe3C / BC electro-Fenton cathode material is 2 mg, 4 mg, 6 mg, and 8 mg, respectively. The result is shown in Table 3. Figure 4 As shown in Table 3, when the cathode material load is 6 mg, the degradation rate of nitenpyram pollutants is the highest.

[0065] Test Example 3

[0066] The degradation performance of the Fe3C / BC electro-Fenton cathode material prepared in Example 1 of the application to nitenpyram pollutants with different initial concentrations is investigated. The electro-Fenton degradation process is carried out according to the steps of Test Example 1, and the difference is only that the initial concentration of nitenpyram pollutants is 5 mg / L, 10 mg / L, 20 mg / L, and 40 mg / L, respectively. The result is shown in Table 4. Figure 5 As shown in Table 4, when the initial concentration of nitenpyram pollutants is in the range of 5-40 mg / L, the efficient degradation can be achieved, which indicates that the Fe3C / BC electro-Fenton cathode material has wide initial concentration applicability in removing nitenpyram pollutants in water.

[0067] Test Example 4

[0068] The performance of the Fe3C / BC electro-Fenton cathode material prepared in Example 1 of the present application in degrading nitenpyram pollutants at different pH values was investigated. The electro-Fenton degradation step was the same as in Test Example 1, except that the initial pH was adjusted to 3, 5, 7 and 9 respectively when the solution was prepared, and the results are shown in Figure 6 As shown in the table, the nitenpyram pollutants can be effectively degraded in the pH range of 3-9, which shows that the Fe3C / BC cathode material prepared in the present application has a wide pH applicability. Further, the Fe3C / BC electro-Fenton cathode material prepared in the present application can quickly degrade nitenpyram at a pH of 3, with a degradation effect of more than 90% in 25 min and complete degradation after 40 min, proving that the present application can quickly degrade nitenpyram under acidic conditions.

[0069] Test Example 5

[0070] The ability of the Fe3C / BC electro-Fenton cathode material prepared in Example 1 of the present application to degrade pollutants at different application potentials was investigated. The electro-Fenton degradation step was the same as in Test Example 1, except that the application potentials applied were -0.2 V, -0.5 V, -0.8 V and -1.1 V respectively, and the results are shown in Figure 7 As shown in the table, as the application potential increases, the degradation efficiency of the nitenpyram pollutants also gradually increases and stabilizes.

[0071] Test Example 6

[0072] The ability of the Fe3C / BC electro-Fenton cathode material prepared in Example 1 of the present application to degrade pollutants in different water matrices was investigated. The electro-Fenton degradation step was the same as in Test Example 1, except that the ultrapure water was replaced with tap water and lake water respectively when the pollutant solution was prepared. As shown in Figure 8 The Fe3C / BC electro-Fenton cathode material prepared in the present application has excellent anti-water matrix interference ability and can be applied to the removal of nitenpyram pollutants in various water bodies.

[0073] Test Example 7

[0074] The cyclic stability of the Fe3C / BC electro-Fenton cathode material prepared in Example 1 of the present application in degrading nitenpyram was investigated, and the specific method was as in Test Example 1. After each cycle, the electrode surface was rinsed with water, and the degradation experiment was repeated, and the results are shown in Figure 9 As shown in the table, the degradation rate of the catalyst to nitenpyram remained at more than 80% after 4 cycles.

[0075] Test Example 8

[0076] The degradation performance of the Fe3C / BC electro-Fenton cathode material prepared in Example 1 of the present application on other neonicotinoid pesticide pollutants was investigated. The electro-Fenton degradation process was implemented according to the steps of Test Example 1, with the only difference being that the pollutant was replaced by imidacloprid (IMI) and thiamethoxam (TMX) respectively, and the results are shown in Figure 10 The Fe3C / BC electro-Fenton cathode material prepared in Example 1 of the present application also has excellent degradation effect on other neonicotinoid pesticides.

[0077] Test Example 9

[0078] The degradation effect of Fe3C / BC in Example 1, BC in Comparative Example 1 and Fe3C in Comparative Example 2 on nitenpyram was investigated. The specific method was as in Test Example 1, with the only difference being that the cathode material was different, and the test results are shown in Figure 11 a. Compared with single BC, the degradation efficiency of the Fe3C / BC cathode material in Example 1 of the present application on nitenpyram pollutant has a significant advantage. Although the degradation effect of single Fe3C on nitenpyram pollutant is slightly better than that of Fe3C / BC, the metal leakage amount of Fe3C is nearly 10 times that of Fe3C / BC Figure 11 b). Therefore, considering both degradation efficiency and stability, the Fe3C / BC electro-Fenton cathode material prepared in the present application has more advantages.

[0079] Test Example 10

[0080] The materials prepared in Example 1 were used in this test example, and the adsorption process in this test example was the same as that in Test Example 1, with the only difference being that no voltage was applied. The anode oxidation process in this test example was the same as that in Test Example 1, with the only difference being that the gas introduced into the reaction solution was nitrogen. The hetero-EF process in this test example was the same as that in Test Example 1. The homo-EF process in this test example was the same as that in Test Example 1, with the only difference being that the cathode in the system was pure carbon cloth, without any material coated on its surface, and homogeneous iron ions (0.2 mg / L) were added to the reaction solution. The degradation performance of nitenpyram pollutant in the above systems is shown in Figure 12 a. After 60 min of reaction, the degradation rates of nitenpyram in the hetero-EF system, the adsorption system, the anode oxidation system and the homo-EF system were 75.8%, 2.4%, 38.6% and 27.2% respectively. In addition, the degradation reaction rate constants of nitenpyram in these systems were 0.02367 min -1 -1, 0.0004 min -1、 -1, 0.0084 min -1 -1 and 0.0053 min-1 Figure 12 b) These results demonstrate the dominant role of the heterogeneous electro-Fenton system, i.e. the Fe3C / BC cathode material prepared in the present application, in the degradation process of nitenpyram pollutants.

[0081] Test Example 11

[0082] The electro-Fenton cathode materials prepared in Example 1 and Comparative Example 1, 600 μL of anhydrous ethanol, 400 μL of water, and 30 μL of Nafion were added to a 1.5 mL centrifuge tube, and after ultrasonic treatment for 40 min, they were uniformly coated on a glassy carbon electrode and air-dried for standby use. The entire characterization process used a three-electrode system, in which the three electrodes were a glassy carbon electrode loaded with Fe3C / BC and BC as the cathode, a Pt sheet electrode as the anode, and a saturated calomel electrode as the reference electrode. Linear sweep voltammetry curves were obtained in 0.05 M Na2SO4 aqueous solution at pH 3 under oxygen (10 mL / min). The electrochemical impedance spectroscopy test process was as follows: the electro-Fenton cathode materials prepared in Example 1 and Comparative Example 1, 600 μL of anhydrous ethanol, 400 μL of water, and 30 μL of Nafion were added to a 1.5 mL centrifuge tube, and after ultrasonic treatment for 40 min, they were uniformly coated on a glassy carbon electrode and air-dried for standby use. The entire characterization process used a three-electrode system, in which the three electrodes were a glassy carbon electrode loaded with Fe3C / BC and BC as the cathode, a Pt sheet electrode as the anode, and a saturated calomel electrode as the reference electrode. The entire test was carried out in 0.1 M KOH (pH 13) solution under nitrogen (10 mL / min). The test results are shown in Figure 13 a, which shows that the Fe3C / BC cathode material has stronger oxygen reduction activity than the single BC. In addition, the Fe3C / BC electro-Fenton cathode material prepared in the present application has smaller electron transfer resistance and mass transfer resistance Figure 13 b).

[0083] Test Example 12

[0084] In summary, the material prepared in Example 1 was used, and the method of Test Example 1 was used, in which the amount of Fe3C / BC electro-Fenton cathode material was 6 mg, and the electro-Fenton degradation experiment was carried out in a gas diffusion electrode using a three-electrode system, in which the three electrodes were a carbon cloth loaded with Fe3C / BC as the cathode, a Pt sheet electrode as the anode, and a saturated calomel electrode as the reference electrode, Na2SO4 solution was used as the electrolyte, and 5 mg / L nitenpyram aqueous solution containing 0.05 M Na2SO4 was used for the electro-Fenton degradation experiment, the pH value of the system was adjusted to 3, the initial voltage was set to -1.1 V, and within 10 min of reaction, the degradation rate of nitenpyram reached 100%.​

Claims

1. A Fe3C / BC electro-Fenton cathode material, characterized in that: The Fe3C / BC electro-Fenton cathode material is formed by mixing and calcining an iron-based metal organic framework material and straw, wherein the iron-based metal organic framework material accounts for 5%-20% of the mass of the straw.

2. The Fe3C / BC electro-Fenton cathode material according to claim 1, characterized in that The metallic iron in the Fe3C / BC electro-Fenton cathode material mainly exists in the form of Fe3C.

3. A method for preparing the Fe3C / BC electro-Fenton cathode material according to claim 1, characterized in that: The steps include: (1) Adding iron salt and diaminoterephthalic acid to an organic solvent, performing a hydrothermal reaction, cooling, washing, and drying to obtain a metal organic framework material; (2) The metal organic framework material obtained in step (1) and straw powder are mixed and ground, and calcined in an inert gas to obtain a Fe3C / BC electro-Fenton cathode material.

4. The preparation method according to claim 3, characterized in that The iron salt in step (1) is selected from any one or more of ferric chloride, ferric nitrate, and ferric acetate.

5. The preparation method according to claim 3, characterized in that The amount of the iron salt added in step (1) is 8-12% g / mL of the organic solvent N,N-dimethylformamide; the amount of diaminoterephthalic acid added is 2-5% g / mL of the organic solvent N,N-dimethylformamide.

6. The preparation method according to claim 3, characterized in that The hydrothermal reaction in step (1) is carried out at a temperature of 100 to 180° C. for 12 to 24 hours.

7. The preparation method according to claim 3, characterized in that In step (2), the mass ratio of the metal organic framework material to the straw is 0.05-0.2:

1.

8. The preparation method according to claim 3, characterized in that In step (2), the inert gas is nitrogen or argon; the heating rate of calcination is 5-10°C, the temperature is 500-900°C, and the calcination time is 1-5 h.

9. Use of the Fe3C / BC electro-Fenton cathode material according to claim 1 in electro-Fenton degradation of neonicotinoid pesticide pollutants.

10. The use according to claim 9, characterized in that The pollutant is nitenpyram, imidacloprid or thiamethoxam, and the electro-Fenton degradation is carried out in a three-electrode system under oxygen conditions, wherein the three electrodes are Fe3C / BC-loaded carbon cloth as a cathode, a Pt sheet as an anode, and a saturated calomel electrode as a reference electrode, and a nitenpyram solution containing sodium sulfate is used as a reaction liquid for the electro-Fenton degradation experiment. The pH value of the system is 3-9, and the reaction time is 40-60 min.

Images