Iron, fluorine and nitrogen co-doped carbon cathode catalyst and its preparation method and application

Abstract

The present invention discloses an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst and its preparation method and application. The preparation method comprises the following steps: mixing iron salt, carbon source, nitrogen source, polytetrafluoroethylene and water, wherein the ratio of iron salt to polytetrafluoroethylene is 0.25g:0.9mL~1.1mL; the obtained iron, fluorine and nitrogen co-doped carbonaceous precursor material is subjected to pyrolysis treatment to obtain an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst. The iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst of the present invention is a novel functional cathode material with excellent performance, and has the advantages of high catalytic activity, excellent cycle performance, good stability, strong practicality, no secondary pollution, etc. It can achieve efficient degradation of antibiotics (such as chloramphenicol) in wastewater, good reusability, low use cost, and has high use value and good application prospects. The preparation method of the present invention also has the advantages of simple process, green environmental protection, low cost, etc., is suitable for large-scale preparation, and is conducive to industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic materials and relates to an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst and a preparation method and application thereof. Background Art

[0002] In recent years, the extensive use of antibiotics has brought potential threats to the environment and human health, which has aroused great concern. Due to its large population and rapid economic growth, China has become the country with the largest consumption and production of antibiotics in the world. As a large number of antibiotics enter the aquatic environment, this may accelerate the development of antibiotic-resistant bacteria and antibiotic-resistant genes, making antibiotic drugs ineffective for disease treatment. Chloramphenicol (CAP) is a widely used chlorinated nitroaromatic antibiotic with good antibacterial properties. Due to the large-scale use of chloramphenicol, the presence of chloramphenicol has been detected in many environments, causing ecological pollution and endangering the health of organisms. In particular, chloramphenicol may have serious harmful effects on biological communities, such as aplastic anemia and genotoxic carcinogenicity. Therefore, considering the non-negligible impact of the widespread use of antibiotics on the ecological environment and public health, it is very important to propose a new method to effectively remove antibiotics in the aquatic environment, especially for the effective removal of CAP.

[0003] Electrochemical reduction technology is an efficient, easy-to-operate, and environmentally friendly remediation technology that can remove pollutants from water by directly providing electrons to dechlorinate or convert nitro groups into amine groups. The reduced substances are less toxic than the original substances and are easier to degrade. The key to effectively treating organic pollutant wastewater using electrochemical reduction technology is how to obtain a cathode catalyst material with high catalytic activity.

[0004] Palladium (Pd) has been proven to be an excellent electrocatalyst for reducing antibiotics by electrocatalytic hydrogenation and dechlorination, but the high cost of palladium metal limits its large-scale commercial application. There is an urgent need to develop new non-precious metal catalysts to replace the existing palladium metal electrocatalysts. At present, transition metal-nitrogen-carbon (MNC) materials are considered to be one of the most promising non-precious metal catalysts, showing high electrocatalytic activity in oxygen reduction reaction and carbon dioxide reduction reaction. However, the existing transition metal-nitrogen-carbon (MNC) materials still have defects such as poor catalytic activity, poor stability, and easy secondary pollution. The electrochemical reduction system constructed with transition metal-nitrogen-carbon (MNC) materials as cathode catalysts still cannot effectively remove antibiotics in water when treating antibiotic wastewater. Therefore, how to obtain a new carbon cathode catalyst with high catalytic activity, excellent cycle performance, good stability, strong practicality, and no secondary pollution is of great significance for achieving effective removal of antibiotics (such as chloramphenicol) in wastewater. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an iron, fluorine and nitrogen co-doped carbon cathode catalyst with high catalytic activity, excellent cycle performance, good stability, strong practicality and no secondary pollution, as well as a preparation method and application thereof.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0007] A method for preparing an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst comprises the following steps:

[0008] S1. Mixing iron salt, carbon source, nitrogen source, polytetrafluoroethylene and water, stirring, and drying to obtain an iron, fluorine, and nitrogen co-doped carbonaceous precursor material; the ratio of the iron salt to polytetrafluoroethylene is 0.25 g: 0.9 mL to 1.1 mL;

[0009] S2. Pyrolyze the iron, fluorine and nitrogen co-doped carbonaceous precursor material obtained in step S1 to obtain an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst.

[0010] The above preparation method is further improved, in step S1, the ratio of the iron salt to polytetrafluoroethylene is 0.25g:1mL, and the mass ratio of the iron salt, the carbon source and the nitrogen source is 0.25:0.25:10.

[0011] The above preparation method is further improved, in step S1, the mixing specifically comprises: mixing the iron salt, the carbon source and the nitrogen source, grinding, and adding polytetrafluoroethylene and water.

[0012] The above preparation method is further improved, and in step S2, the pyrolysis treatment is specifically: under an inert atmosphere, the iron fluorine nitrogen co-doped carbonaceous precursor material is first pyrolyzed at 580°C to 620°C for 1h to 3h, and then pyrolyzed at 880°C to 920°C for 1h to 3h; the heating rate during the pyrolysis treatment is 2.5°C / min, and the inert atmosphere is nitrogen.

[0013] The above preparation method is further improved, in step S1, the iron salt is ferric nitrate nonahydrate, the carbon source is a carbohydrate substance, the carbohydrate substance is glucose, the nitrogen source is at least one of melamine and urea, the volume ratio of polytetrafluoroethylene to water is 0.9-1.1:10; the stirring time is 30min-45min, the drying time is 24h-45h, the drying is freeze-drying, and the freeze-drying is carried out under vacuum conditions.

[0014] As a general technical concept, the present invention also provides an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst prepared by the above-mentioned preparation method.

[0015] The above-mentioned iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst is further improved, wherein the iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst includes defective carbon, and the defective carbon is doped with iron atoms, nitrogen atoms, and fluorine atoms. The atomic percentage of nitrogen atoms in the iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst is 5.45%, the atomic percentage of fluorine atoms is 0.51%, and the atomic percentage of iron atoms is 0.56%; the iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst is a nanosheet structure.

[0016] As a general technical concept, the present invention also provides an application of the above-mentioned iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst in treating antibiotic wastewater.

[0017] The above application is further improved and includes the following steps: mixing the iron, fluorine and nitrogen co-doped carbon cathode catalyst with antibiotic wastewater, performing an electrochemical reduction reaction, and completing the treatment of the antibiotic wastewater; the amount of the iron, fluorine and nitrogen co-doped carbon cathode catalyst added is 5 mg to 50 mg of the iron, fluorine and nitrogen co-doped carbon cathode catalyst per liter of antibiotic wastewater.

[0018] The above application is further improved, wherein the electrochemical reduction reaction process also includes adding an electrolyte to the antibiotic wastewater so that the concentration of the electrolyte in the reaction system is 0.05M, and the electrolyte is sodium sulfate; the initial concentration of the antibiotic in the antibiotic wastewater is ≤10mg / L, the antibiotic in the antibiotic wastewater is chloramphenicol, and the pH value of the antibiotic wastewater is 3-11; the carbon felt is used as the cathode and the platinum sheet is used as the anode in the reaction system of the electrochemical reduction reaction; the constant current of the reaction system is controlled to be 10mA-50mA during the electrochemical reduction reaction; the electrochemical reduction reaction is carried out under stirring conditions, the stirring speed is 450rpm-550rpm, and the time of the electrochemical reduction reaction is 60min.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] (1) In view of the defects of existing transition metal-nitrogen-carbon (MNC) materials, such as poor catalytic activity, poor stability and easy secondary pollution, and the defect that the electrochemical reduction system constructed with transition metal-nitrogen-carbon (MNC) materials as cathode catalysts cannot effectively remove antibiotics in water when treating antibiotic wastewater, the present invention creatively proposes a method for preparing an iron-fluorine-nitrogen co-doped carbonaceous cathode catalyst, adopting a "one-step polymer-assisted pyrolysis" preparation strategy without any subsequent treatment, specifically: fully mixing iron salt, carbon source, nitrogen source, polytetrafluoroethylene and water, wherein the ratio of iron salt to polytetrafluoroethylene is 0.25g:0.9mL~1.1mL, and drying to obtain an iron-fluorine-nitrogen co-doped carbonaceous precursor material; then, pyrolyzing the iron-fluorine-nitrogen co-doped carbonaceous precursor material to obtain an iron-fluorine-nitrogen co-doped carbonaceous cathode catalyst. The preparation method of the present invention, on the one hand, the nitrogen source first polymerizes to form graphite carbon nitride during the pyrolysis treatment process, and then forms carbon nanosheets as a 2D template / precursor in the presence of a carbon source, and at the same time, the polytetrafluoroethylene embedded in the carbon intermediate is used as a sacrificial reagent to prevent the combination of iron atoms, so that the number of active sites of the catalyst increases, which will be conducive to the direct transfer of electrons, and then improve the electrochemical activity of the material; on the other hand, a large amount of N and F-containing gases will be released during the pyrolysis treatment process, which can act as a heteroatom source to induce N and F atoms to be densely doped around the Fe active sites in the carbon lattice, thereby improving the stability of the material. The iron fluorine nitrogen co-doped carbonaceous cathode catalyst prepared by the present invention is a novel functional cathode material with excellent performance, with high catalytic activity, excellent cycle performance, good stability, strong practicality, no secondary pollution and other advantages, can achieve efficient degradation of antibiotics (such as chloramphenicol) in wastewater, and good reusability, low cost of use, with very high use value and good application prospects. In addition, the preparation method of the present invention has the advantages of simple process, green environmental protection, low cost, suitable for large-scale preparation, and is conducive to industrial application.

[0021] (2) The preparation method of the present invention can make the iron nanoparticles more evenly dispersed by optimizing the ratio of iron salt to polytetrafluoroethylene to 0.25 g:1 mL and the mass ratio of iron salt, carbon source and nitrogen source to 0.25:0.25:10, thereby further improving the catalytic performance of the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst, and ultimately achieving efficient degradation of antibiotics in wastewater.

[0022] (3) The present invention also provides an application of an iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst in the treatment of antibiotic wastewater. The iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst and antibiotic wastewater are mixed to carry out an electrochemical reduction reaction, which can achieve efficient degradation of antibiotics in the wastewater. The method has the advantages of simple operation, mild reaction conditions, low cost, good removal effect, and easy recycling and reuse. It also has strong adaptability and can degrade antibiotic wastewater under conditions of different pH values ​​and the coexistence of multiple ions. The method is a new method that is widely used and can efficiently remove antibiotics from water bodies. It has high use value and good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a microscopic morphology of the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) in Example 1 of the present invention.

[0024] Figure 2 These are the XRD diagrams of the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) in Example 1 of the present invention, the carbonaceous cathode catalyst (Fe-NC) in Comparative Example 1, and the carbonaceous cathode catalyst (FNC) in Comparative Example 2.

[0025] Figure 3 This is a diagram showing the degradation effect of chloramphenicol on the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) in Example 2 of the present invention, the carbonaceous cathode catalyst (Fe-NC) in Comparative Example 1, and the carbonaceous cathode catalyst (FNC) in Comparative Example 2.

[0026] Figure 4 This is a diagram showing the cyclic degradation effect of chloramphenicol by the iron, fluorine and nitrogen co-doped carbon cathode catalyst (Fe-FNC) in Example 3 of the present invention.

[0027] Figure 5 This is a diagram showing the dissolution effect of iron when chloramphenicol is cyclically treated with the iron-fluorine-nitrogen co-doped carbon cathode catalyst (Fe-FNC) in Example 3 of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0029] Embodiment 1:

[0030] A method for preparing an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst of the present invention comprises the following steps:

[0031] (1) 0.25 g of Fe(NO3)3·9H2O, 0.25 g of glucose, and 10 g of melamine were put into a mortar and ground in sequence to obtain a completely mixed yellow powdery mixture.

[0032] (2) Add 1 mL of polytetrafluoroethylene and 10 mL of deionized water to the mixture obtained in step (1), and stir for 30 min to obtain a mixed solution.

[0033] (3) freeze-drying the mixed solution obtained in step (2) under vacuum conditions for 24 hours to obtain an iron, fluorine and nitrogen co-doped carbonaceous precursor material.

[0034] (4) The iron, fluorine and nitrogen co-doped carbonaceous precursor material of step (3) is transferred to a tubular furnace, and pyrolyzed at 600°C at a heating rate of 2.5°C / min for 1 h in a nitrogen atmosphere, and then pyrolyzed at 900°C at a heating rate of 2.5°C / min for 1 h. After naturally cooling to room temperature under nitrogen protection, an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst is obtained, which is recorded as Fe-FNC.

[0035] In this embodiment, the XPS characterization results of the iron-fluorine-nitrogen co-doped carbon cathode catalyst (Fe-FNC) show that its atomic percentage content is C: 93.48%, N: 5.45%, F: 0.51%, and Fe: 0.56%.

[0036] In this embodiment, iron fluoride and nitrogen co-doped carbonaceous precursor materials with different amounts of polytetrafluoroethylene were also prepared. The preparation method was basically the same as the preparation method of iron fluoride and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC), with the only difference being that in step (2), the amounts of polytetrafluoroethylene were 0.75 mL and 1.2 mL, respectively; and the obtained iron fluoride and nitrogen co-doped carbonaceous precursor materials were respectively recorded as Fe-FNC-1 and Fe-FNC-2.

[0037] Figure 1 This is a microscopic morphology of the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) in Example 1 of the present invention. Figure 1 In the figure, (a) is SEM, (b) and (c) are TEM. Figure 1 It can be seen that the SEM image of the iron-fluorine-nitrogen co-doped carbon cathode catalyst (Fe-FNC) of the present invention shows that Fe-FNC is composed of folded, cloud-like nanosheets, and the interconnected structure of Fe-FNC helps to avoid the dense accumulation of ultra-thin nanosheet layers, and can maintain ultra-thin nanosheets while having large lateral dimensions, thereby achieving uniform distribution of iron atomic sites. The TEM image of Fe-FNC shows that many nanoparticles are embedded in the porous carbon matrix, and the nanoparticles are well crystallized, uniform in size, and highly dispersed, which is not only conducive to reducing the loss of catalytic activity, but also conducive to promoting electron transfer in the catalytic process.

[0038] Comparative Example 1:

[0039] A carbonaceous cathode catalyst, the preparation method of which is basically the same as the preparation method of the iron-fluorine-nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) in Example 1, the only difference being that in step (2), polytetrafluoroethylene is not added; the carbonaceous cathode catalyst prepared is denoted as Fe-NC.

[0040] Comparative Example 2:

[0041] A carbonaceous cathode catalyst, the preparation method of which is basically the same as the preparation method of the iron-fluorine-nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) in Example 1, the only difference being that in step (1), Fe(NO3)3·9H2O is not added; the prepared carbonaceous cathode catalyst is denoted as FNC.

[0042] Figure 2 The XRD diagrams of the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) in Example 1 of the present invention, the carbonaceous cathode catalyst (Fe-NC) in Comparative Example 1, and the carbonaceous cathode catalyst (FNC) in Comparative Example 2 are shown in FIG. Figure 2 It can be seen that the addition of fluorine-containing PTFE during the preparation of Fe-FNC greatly promotes the high dispersion of iron, thereby causing the diffraction peak of metallic iron to disappear.

[0043] Embodiment 2:

[0044] An application of the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst of the present invention in treating antibiotic wastewater, specifically treating a chloramphenicol solution using the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst as a reaction catalyst, comprising the following steps:

[0045] Take 5 portions of 200 mL, pH value of 5.8, initial concentration of 10 mg / L chloramphenicol solution and place them in a 250 mL reactor, insert the cathode and anode in parallel, wherein the cathode is pretreated commercial carbon felt (CF), and the platinum sheet is used as the anode. 10 mg of iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) in Example 1, iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC-1), iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC-2), carbonaceous cathode catalyst (Fe-NC) in Comparative Example 1, and carbonaceous cathode catalyst (FNC) in Comparative Example 2 are added as reaction catalysts, and anhydrous sodium sulfate is added and stirred until completely dissolved so that the concentration of sodium sulfate in the system is 0.05 M, and then a constant current power supply of 50 mA is applied, and then an electrochemical reduction reaction is carried out at a stirring speed of 500 rpm for 60 min to complete the treatment of the chloramphenicol solution.

[0046] In this embodiment, the processing method of the pretreated commercial carbon felt (CF) is: cutting the commercial carbon felt (CF) into 3 cm×2 cm, and then ultrasonically cleaning it with 100 mL of acetone, ethanol and ultrapure water respectively to obtain the pretreated commercial carbon felt (CF).

[0047] Control group 1 (direct cathode reduction): No reaction catalyst was added in the electrochemical reduction reaction.

[0048] Control group 2 (adsorption reaction): 200 mL of chloramphenicol solution with a pH value of 5.8 and an initial concentration of 10 mg / L was placed in a 250 mL reactor, 10 mg of the iron, fluorine and nitrogen co-doped carbon cathode catalyst (Fe-FNC) in Example 1 was added as a catalyst, and the mixture was continuously stirred on a constant temperature stirrer at 25°C for 60 minutes to complete the treatment of the chloramphenicol solution.

[0049] During the reaction process, 1 mL of sample was taken out from the solution at a preset time point, collected after passing through a 0.45 μm filter membrane, and the residual chloramphenicol concentration in the solution was determined on a high performance liquid chromatography. The detection method was set as follows: wavelength λ = 278 nm, the ratio of the mobile phase was: methanol: water = 60:40, the flow rate was 1 mL / min, and the injection volume was 10 μL.

[0050] In this embodiment, the removal rates of chloramphenicol by the iron, fluorine and nitrogen co-doped carbon cathode catalyst (Fe-FNC-1) and the iron, fluorine and nitrogen co-doped carbon cathode catalyst (Fe-FNC-2) were 87.9% and 85.8%, respectively.

[0051] Figure 3 The figure shows the degradation effect of iron, fluorine and nitrogen co-doped carbon cathode catalyst (Fe-FNC) in Example 2 of the present invention, the carbon cathode catalyst (Fe-NC) in Comparative Example 1, and the carbon cathode catalyst (FNC) in Comparative Example 2 on chloramphenicol. Figure 3 It can be seen that in the control group 1, no reaction catalyst was added but direct cathode reduction was performed, and its removal rate of chloramphenicol was 36.1%; in the control group 2, no electrochemical reduction reaction was performed but adsorption reaction was performed, and its removal rate of chloramphenicol was 20.0%; the removal rates of chloramphenicol by iron, fluorine and nitrogen co-doped carbon cathode catalyst (Fe-FNC), carbon cathode catalyst (Fe-NC), and carbon cathode catalyst (FNC) were 99.4%, 90.2%, and 89.0%, respectively.

[0052] Embodiment 3:

[0053] The reusability of the Fe-FNC co-doped carbon cathode catalyst (Fe-FNC) was investigated, specifically, the chloramphenicol solution was treated with the Fe-FNC co-doped carbon cathode catalyst as a reaction catalyst for multiple cycles, including the following steps:

[0054] (1) 200 mL of a chloramphenicol solution having a pH value of 5.8 and an initial concentration of 10 mg / L was placed in a 250 mL reactor, and a cathode and an anode were inserted in parallel, wherein the cathode was a pretreated commercial carbon felt (CF), and a platinum sheet was used as an anode. 10 mg of the iron-fluorine-nitrogen co-doped carbon cathode catalyst (Fe-FNC) in Example 1 was added as a reaction catalyst, and anhydrous sodium sulfate was added and stirred until completely dissolved, so that the concentration of sodium sulfate in the system was 0.05 M. Then, a constant current power supply of 50 mA was applied, and an electrochemical reduction reaction was performed at a stirring speed of 500 rpm for 60 min to complete one cycle.

[0055] (2) After completing one cycle, the reaction system in step (1) is filtered and separated, rinsed with deionized water, and dried at 60° C. to obtain a regenerated iron-fluorine-nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC).

[0056] (3) Using the regenerated iron-fluorine-nitrogen co-doped carbon cathode catalyst (Fe-FNC) obtained in step (2) as a reaction catalyst, repeating steps (1) and (2) for a total of 5 times to complete multiple cycle experiments.

[0057] During each electrochemical reduction reaction, 1 mL of sample was taken out from the solution at a preset time point, collected after passing through a 0.45 μm filter membrane, and the residual chloramphenicol concentration in the solution was determined on a high performance liquid chromatography. The detection method was set as follows: wavelength λ = 278 nm, the ratio of the mobile phase was: methanol: water = 60:40, the flow rate was 1 mL / min, and the injection volume was 10 μL.

[0058] Figure 4 This is a graph showing the cyclic degradation effect of chloramphenicol by the iron, fluorine and nitrogen co-doped carbon cathode catalyst (Fe-FNC) in Example 3 of the present invention. Figure 4 It can be seen that after the iron, fluorine and nitrogen co-doped carbon cathode catalyst (Fe-FNC) of the present invention is reused for 5 times, the removal rate of chloramphenicol can still reach 90%, which shows excellent recycling ability and has good industrial application prospects.

[0059] Figure 5 This is a diagram showing the effect of iron dissolution when the iron-fluorine-nitrogen co-doped carbon cathode catalyst (Fe-FNC) is used to cyclically treat chloramphenicol in Example 3 of the present invention. Figure 5 It can be seen that when the iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) treats chloramphenicol in each cycle, the dissolution of iron is less than 0.1 mg / L, which indicates that the iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst (Fe-FNC) of the present invention has good stability.

[0060] In summary, the preparation method of the iron fluorine nitrogen co-doped carbonaceous cathode catalyst of the present invention, the introduction of polytetrafluoroethylene as a fluorine atom source, can have a large lateral size while maintaining an ultra-thin nanosheet, thereby achieving a uniform distribution of iron atom sites, which is conducive to promoting electron transfer in the catalytic process. The iron fluorine nitrogen co-doped carbonaceous cathode catalyst of the present invention is a novel functional cathode catalyst material with excellent performance, with high catalytic activity, excellent cycle performance, good stability, strong practicality, no secondary pollution and other advantages, can achieve efficient degradation of antibiotics (such as chloramphenicol) in wastewater, and good reusability, low use cost, has a very high use value and a good application prospect, and is of great significance for effectively removing antibiotics in water bodies. In addition, the preparation method of the present invention also has the advantages of simple process, green environmental protection, low cost, etc., is suitable for large-scale preparation, and is conducive to industrial application.

[0061] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. Application of an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst in treating antibiotic wastewater, characterized in that: The following steps are involved: The iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst and antibiotic wastewater are mixed to carry out an electrochemical reduction reaction to complete the treatment of the antibiotic wastewater; the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst is added in an amount of 5 mg to 50 mg per liter of antibiotic wastewater; the preparation method of the iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst comprises the following steps: S1. Mix an iron salt, a carbon source and a nitrogen source, grind them, add polytetrafluoroethylene and water, stir, and dry to obtain an iron, fluorine and nitrogen co-doped carbonaceous precursor material; the ratio of the iron salt to the polytetrafluoroethylene is 0.25 g: 0.9 mL to 1.1 mL; the carbon source is a carbohydrate; S2. The iron, fluorine and nitrogen co-doped carbonaceous precursor material obtained in step S1 is first subjected to pyrolysis treatment at 580° C. to 620° C. for 1 h to 3 h, and then subjected to pyrolysis treatment at 880° C. to 920° C. for 1 h to 3 h, to obtain an iron, fluorine and nitrogen co-doped carbonaceous cathode catalyst.

2. The use according to claim 1, characterized in that: In step S1, the ratio of the iron salt to polytetrafluoroethylene is 0.25 g:1 mL, and the mass ratio of the iron salt to the carbon source to the nitrogen source is 0.25:0.25:

10.

3. The use according to claim 1, characterized in that: In step S2, the pyrolysis treatment is carried out under an inert atmosphere; the heating rate during the pyrolysis treatment is 2.5°C / min, and the inert atmosphere is nitrogen.

4. The use according to claim 1, characterized in that: In step S1, the iron salt is ferric nitrate nonahydrate, the sugar substance is glucose, the nitrogen source is at least one of melamine and urea, the volume ratio of polytetrafluoroethylene to water is 0.9-1.1:10; the stirring time is 30 minutes to 45 minutes, the drying time is 24 hours to 45 hours, the drying is freeze drying, and the freeze drying is carried out under vacuum conditions.

5. The use according to any one of claims 1 to 4, characterized in that: The iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst includes defective carbon, which is doped with iron atoms, nitrogen atoms, and fluorine atoms. The atomic percentage of nitrogen atoms in the iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst is 5.45%, the atomic percentage of fluorine atoms is 0.51%, and the atomic percentage of iron atoms is 0.56%. The iron, fluorine, and nitrogen co-doped carbonaceous cathode catalyst is a nanosheet structure.

6. The use according to claim 1, characterized in that: The electrochemical reduction reaction process also includes adding electrolyte to the antibiotic wastewater so that the concentration of the electrolyte in the reaction system is 0.05M, and the electrolyte is sodium sulfate; the initial concentration of the antibiotic in the antibiotic wastewater is ≤10mg / L, the antibiotic in the antibiotic wastewater is chloramphenicol, and the pH value of the antibiotic wastewater is 3-11; the reaction system of the electrochemical reduction reaction uses carbon felt as the cathode and the platinum sheet as the anode; the constant current of the reaction system is controlled to be 10mA-50mA during the electrochemical reduction reaction; the electrochemical reduction reaction is carried out under stirring conditions, the stirring speed is 450rpm-550rpm, and the time of the electrochemical reduction reaction is 60min.

Images