Synthesis of heterogeneous Fenton catalyst and application of heterogeneous Fenton catalyst in degradation of PFAS

Abstract

The invention relates to synthesis of a heterogeneous Fenton catalyst and application of the heterogeneous Fenton catalyst to degradation of PFAS, and belongs to the technical field of environmental engineering water treatment. The preparation method comprises the following steps: roasting an MOF material in a non-oxidizing atmosphere to obtain a carbonized MOF material, taking the carbonized MOF material as a template, synthesizing FeS2 by taking FeSO4, Na2S2O3 and elemental sulfur as raw materials through a hydrothermal method, and preparing to obtain the heterogeneous Fenton catalyst. Then, a three-electrode system is constructed, FeS2-MOF (at) C is used as a catalyst for efficiently degrading PFAS, and the heterogeneous Fenton catalyst has the advantages of being stable in crystal structure, high in electron transfer efficiency, excellent in catalytic performance and the like and is suitable for being used for removing various organic pollutants difficult to degrade.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental engineering water treatment, and more specifically, relates to the synthesis of a heterogeneous Fenton catalyst and its application in degrading PFAS. Background Art

[0002] Perfluorooctanoic acid (PFOA), as a common polyfluorinated and / or perfluorinated compound (PFAS), poses a serious threat to the environment and biological health due to its chemical stability and difficulty in degradation. Traditional water treatment methods, such as activated carbon adsorption, chemical oxidation and biodegradation, have limited effects on the removal of PFOA and are difficult to meet actual needs. Therefore, it is of great significance to develop new and efficient removal technologies. The electro-Fenton technology generates hydroxyl radicals (·OH) with strong oxidizing ability through the H2O2 produced by water electrolysis under the action of catalysts, thereby efficiently degrading organic pollutants. Compared with the traditional Fenton reaction, the electro-Fenton method can be carried out under milder conditions and can continuously generate H2O2, with high degradation efficiency and environmental friendliness. However, the key to the electro-Fenton method lies in the selection and design of the catalyst. The ideal catalyst should have efficient H2O2 decomposition ability, stable crystal structure and excellent electron transfer performance. Metal-organic framework materials (MOFs) have become ideal electro-Fenton catalyst materials due to their excellent structure and catalytic performance, but their single application has problems such as stability and electron transfer efficiency.

[0003] In a recent study, Wang et al. prepared Fe / S-doped aerogel Fenton catalyst and applied it to the degradation of PFOA. The PFOA degradation rate was only 21.6% within 3 hours [Sci. Total Environ., 2020, 714: 136436]. The preparation process is complicated, time-consuming, low-yield and energy-intensive. Summary of the invention

[0004] The present invention provides a heterogeneous Fenton catalyst and a method for efficiently removing PFAS by an electro-Fenton method of in-situ generating H2O2, using a carbonized MOF material as a template and FeSO 4、 Na2S2O3 and sulfur are used as raw materials, FeS2 is synthesized by hydrothermal method, and a heterogeneous Fenton catalyst is prepared. The heterogeneous Fenton catalyst prepared by the present invention has the characteristics of stable crystal structure, high electron transfer efficiency, excellent catalytic performance, wide adaptability to reaction environment, etc. The effect of efficient removal of PFAS is achieved through the synergistic effect of efficient and stable catalyst and electrochemical reaction. Thereby solving the technical problem of low degradation efficiency of polyfluorinated and / or perfluorinated compounds in the prior art.

[0005] According to a first aspect of the present invention, there is provided a method for synthesizing a heterogeneous Fenton catalyst, comprising the following steps:

[0006] (1) calcining the MOF material in a non-oxidizing atmosphere to obtain a carbonized MOF material;

[0007] (2) Using the carbonized MOF material obtained in step (1) as a template, FeSO 4、 Na2S2O3 and sulfur were used as raw materials, and FeS2 was synthesized by hydrothermal method to obtain a heterogeneous Fenton catalyst with carbonized MOF material as template.

[0008] Preferably, in step (1), the MOF material is prepared by a microwave method.

[0009] Preferably, the synthesis conditions of the microwave method are 20-40 minutes, 50-150W / tank power and 100-140°C temperature.

[0010] Preferably, in step (1), the MOF material is MOF-74 material, which is synthesized from raw materials FeSO4·7H2O and 2,5-dihydroxyterephthalic acid.

[0011] Preferably, in step (1), the calcination temperature is 400-600° C., the heating rate is 4-6° C. / min, and the holding time is 1-3 hours.

[0012] According to another aspect of the present invention, a heterogeneous Fenton catalyst prepared by any one of the methods is provided.

[0013] According to another aspect of the present invention, there is provided the use of the heterogeneous Fenton catalyst for degrading polyfluorinated and / or perfluorinated compounds.

[0014] Preferably, the application is the degradation and removal of polyfluorinated and / or perfluorinated organic pollutants by a three-electrode system electro-Fenton process.

[0015] Preferably, the application is specifically as follows: using copper-deposited graphite felt as a working electrode, a boron-doped diamond electrode as a counter electrode, an Ag / AgCl electrode as a reference electrode, and Na2SO4 as an electrolyte, the heterogeneous Fenton catalyst and the pollutant are added to the electrolyte for dispersion; the working electrode is used to reduce O2 in an aqueous solution to produce H2O2, and the heterogeneous Fenton catalyst is used to accelerate the decomposition of H2O2, thereby catalyzing the generation of more active oxygen species, thereby achieving efficient degradation of the pollutants.

[0016] Preferably, the mass volume ratio of the heterogeneous Fenton catalyst to the electrolyte divided by the concentration of the organic pollutant is 30-60; the voltage applied by the electro-Fenton method is -0.5 to -1.0 V, the reaction time is less than 3 hours, and the aeration rate is 2.5 L / min.

[0017] In general, the above technical solutions conceived by the present invention can achieve at least the following beneficial effects compared with the prior art:

[0018] (1) The heterogeneous Fenton catalyst of the present invention has the characteristics of stable crystal structure, high electron transfer efficiency, superior catalytic performance, wide adaptability to reaction environment, etc., and has broad application prospects in environmental pollution control. The research of the present invention not only provides new ideas for the development of electro-Fenton technology, but also provides an effective solution for the treatment of difficult-to-degrade organic pollutants in practical applications.

[0019] (2) The present invention proposes a preparation method of a composite catalyst (FeS2-MOF@C) based on MOF (preferably MOF-74(Fe)) and its application in the electro-Fenton method. The heterogeneous Fenton catalyst has the characteristics of stable crystal structure, high electron transfer efficiency, superior catalytic performance, and wide adaptability to reaction environments, and has broad application prospects in environmental pollution control. The research of the present invention not only provides new ideas for the development of electro-Fenton technology, but also provides an effective solution for the treatment of difficult-to-degrade organic pollutants in practical applications.

[0020] (3) The present invention preferably uses a FeS2-MOF@C composite catalyst prepared by microwave-assisted synthesis, nitrogen atmosphere calcination and hydrothermal method, combined with a copper-deposited graphite felt electrode (GF / Cu), a boron-doped diamond electrode (BDD electrode) and an Ag / AgCl reference electrode to construct a three-electrode system. The BDD electrode is used to capture the electrons of the PFAS carboxyl group, and then the unstable carboxyl group is separated from the PFAS and converted into CO2, which is beneficial to the further defluorination of PFAS; GF / Cu is used to efficiently reduce O2 in the aqueous solution to produce H2O2, and the heterogeneous Fenton catalyst is used to accelerate the decomposition of H2O2 and catalyze the generation of more active oxygen species, thereby achieving efficient degradation of PFAS.

[0021] (4) Preferably, the present invention uses a microwave-assisted synthesis method to synthesize MOF-74(Fe). Compared with the traditional thermodynamic synthesis method, microwave radiation can significantly improve the rate and efficiency of chemical reactions. Under microwave heating, MOF-74(Fe) can be synthesized efficiently and in high yield, and its crystal structure, stability and surface morphology can be optimized, laying a solid foundation for the subsequent performance improvement of the catalyst.

[0022] (5) The present invention uses MOF-74 as a carrier and successfully synthesizes FeS2 by a hydrothermal method to form a FeS2-MOF@C heterogeneous Fenton catalyst. The high surface area and pore structure of MOF provide good carrier support, which is conducive to the uniform dispersion and immobilization of FeS2, thereby enhancing the stability and catalytic activity of the catalyst. This composite strategy not only effectively improves the specific surface area and reaction activity of the catalyst, but also slows down the deactivation rate of FeS2 in the electro-Fenton reaction and prolongs the service life of the catalyst.

[0023] (6) The FeS2-MOF@C heterogeneous Fenton catalyst proposed in the present invention exhibits excellent stability during the reaction process. Compared with the method of sulfurizing MOF@C in a tubular furnace, the template method selected in the present invention helps to form a FeS2-MOF@C catalyst with a more stable crystal structure. In addition, high-temperature sulfurization treatment in a tubular furnace may also lead to problems of heterogeneity and deactivation of the catalyst crystal structure, limiting its practical application in complex environments.

[0024] (7) The FeS2-MOF@C heterogeneous Fenton catalyst proposed in the present invention exhibits excellent catalytic activity and stability in the electro-Fenton method, and can efficiently generate various active oxygen species, thereby significantly improving the degradation efficiency of difficult-to-degrade organic pollutants such as PFOA. Compared with traditional chemical oxidation methods, it is more efficient and does not produce secondary pollutants, and is suitable for practical applications under complex water quality conditions.

[0025] (8) The electro-Fenton system designed by the present invention can not only be used to remove PFOA, but also has the potential to treat other difficult-to-degrade organic pollutants. The heterogeneous Fenton catalyst of the present invention has a removal rate of 100% and a defluorination rate of 76% for 10 mg / L PFOA within 3 hours. After three cycles, it can still maintain a removal rate of 94% and a defluorination rate of 71%. By adjusting the catalyst ratio and reaction conditions, efficient degradation of a variety of organic pollutants can be achieved, which is suitable for the treatment of wastewater of different types and concentrations.

[0026] (9) The electro-Fenton method used in the present invention is a low-energy, low-pollution environmental management technology, and the present invention further optimizes the design of the catalyst, reduces the dependence on external chemicals and the risk of secondary pollution, and meets the environmental protection requirements of sustainable development. Through this technology, water quality can be effectively improved, and the ecological environment and human health can be protected. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Scanning electron microscopy images of different types of catalysts.

[0028] Figure 2 This is the XRD pattern of the FeS2-MOF@C catalyst prepared in Example 1.

[0029] Figure 3 This is a diagram showing the effect of electro-Fenton removal of PFOA using different types of catalysts.

[0030] Figure 4 This is a diagram showing the effect of electro-Fenton removal of PFOA at different dosages of FeS2-MOF@C catalyst.

[0031] Figure 5 This is a diagram showing the effect of FeS2-MOF@C catalyst on electro-Fenton removal of PFOA at different voltages.

[0032] Figure 6 This is the effect of FeS2-MOF@C catalyst on electro-Fenton removal of PFOA and the defluorination rate under different cycles.

[0033] Figure 7 This is a diagram showing the effect of FeS2-MOF@C catalyst on electro-Fenton removal of PFOA under the action of different counter electrodes. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The present invention provides a heterogeneous Fenton catalyst and a preparation method thereof, and is applied to the efficient removal of PFAS in the electro-Fenton method. Preferably, the specific steps include: using a microwave digestion instrument to synthesize MOF-74 (Fe) with excellent crystal structure by a microwave-assisted method; calcining the synthesized MOF-74 in a tubular furnace under a nitrogen atmosphere to obtain MOF@C; using MOF@C as a template, synthesizing FeS2 by a hydrothermal method to prepare a FeS2-MOF@C heterogeneous Fenton catalyst; constructing a three-electrode system, using GF / Cu as a working electrode, BDD as a counter electrode, Ag / AgCl as a reference electrode, using FeS2-MOF@C as a catalyst, and efficiently degrading PFAS by the electro-Fenton method.

[0036] Preferably, the concentration ratio of the raw materials FeSO4·7H2O and 2,5-dihydroxyterephthalic acid for synthesizing MOF-74 is 4:1-1:4.

[0037] Further preferably, the molar ratio of the raw materials FeSO4·7H2O and 2,5-dihydroxyterephthalic acid for synthesizing MOF-74 is 1:2 (1.25 mmol:2.5 mmol), and the corresponding masses are 0.2477 g and 0.4971 g, respectively.

[0038] Further preferably, the solvent for synthesizing MOF-74 is N,N-dimethylformamide, anhydrous ethanol and water in a ratio of 15:1:1; the total volume of the mixed solvent during the synthesis process is 20 mL, and 0.3 g of polyvinyl pyrrolidone (PVP) is dissolved in the mixed solution.

[0039] Preferably, the microwave-assisted synthesis of MOF-74 is performed using a microwave digester, and the synthesis conditions are: time 20-40 minutes, power 50-150 W / tank, and temperature 100-140°C.

[0040] Preferably, the synthetic MOF-74 is washed three times with anhydrous ethanol and three times with water respectively.

[0041] Preferably, in the process of using a tubular furnace to calcine MOF-74 to generate MOF@C, the conditions of the tubular furnace are set as follows: calcination temperature is 400-600°C, heating rate is 4-6°C / min, and holding time is 1-3 hours.

[0042] Preferably, when synthesizing FeS2-MOF@C, the concentration range of FeSO4·7H2O is 1-2 mol / L, the concentration range of Na2S2O3 is 1-2 mol / L, the concentration range of high-purity sulfur is 0.5-1 mol / L, and the mass volume ratio of MOF@C to solvent is 3-20 mg / mL.

[0043] Further preferably, when synthesizing FeS2-MOF@C, 0.05 mol FeSO4·7H2O, 0.05 mol Na2S2O3, and 0.025 mol high-purity sulfur are dissolved in 30 mL ethylene glycol, and finally 0.4 g MOF@C is poured in and stirred evenly, and then placed in a high-pressure reactor and reacted at 180°C for 24 hours.

[0044] Preferably, the washing method during the synthesis of FeS2-MOF@C is to repeatedly centrifuge and wash with dilute sulfuric acid, anhydrous ethanol, and carbon disulfide in sequence.

[0045] Preferably, the conditions for preparing the GF / Cu electrode are: an area of ​​3×3.5 cm, an electrodeposition solution of 200 mL of a mixed solution of 50 mM and 0.5 M CuSO4·5H2O and H2SO4, a deposition voltage of -0.6 V, and a deposition time of 60 s.

[0046] Preferably, the counter electrode is a 2×2 cm BDD electrode; and the reference electrode is an Ag / AgCl electrode.

[0047] Preferably, the mass volume ratio of the heterogeneous Fenton catalyst to the electrolyte divided by the concentration of the organic pollutant is 30-60;

[0048] Further preferably, in the electro-Fenton method for efficient degradation of PFAS, the amount of catalyst used in the reaction process is 0.4 g / L, the applied voltage is -0.8 V, the reaction time is 3 hours, the aeration rate is 2.5 L / min, the PFOA concentration is 10 mg / L, the electrolyte volume is 100 mL, and the electrolyte is 0.1 M Na2SO4.

[0049] The following are specific embodiments

[0050] Example 1 Preparation of FeS2-MOF@C Catalyst

[0051] (1) Synthesis of MOF: MOF-74(Fe) was synthesized by microwave-assisted method using microwave digestion instrument. Specifically, FeSO4·7H2O and 2,5-dihydroxyterephthalic acid were dissolved in a mixed solvent of N,N-dimethylformamide, ethanol and water (ratio of 15:1:1, total volume of 20 mL) in a molar ratio of 1:2 (1.25mmol:2.5mmol), corresponding to masses of 0.2477g and 0.4971g, respectively, and 0.3g of PVP was added. The solution was placed in a microwave digestion instrument, and the synthesis conditions were 30 minutes, power 100W / tank, and temperature 120°C. The product was washed three times with anhydrous ethanol and pure water.

[0052] (2) Synthesis of MOF@C: The synthesized MOF-74 was calcined in a tubular furnace under a nitrogen atmosphere at a calcination temperature of 500°C, a heating rate of 5°C / min, and a holding time of 2 h to obtain a carbonized MOF (MOF@C).

[0053] (3) Synthesis of FeS2-MOF@C: Weigh 0.05 mol FeSO4·7H2O, 0.05 mol Na2S2O3 and 0.025 mol high-purity sulfur, add 30 mL ethylene glycol, and then add 0.4 g MOF@C and stir to mix evenly. Put it into a high-pressure reactor and react at 180°C for 24 h. Then, wash it repeatedly by centrifugation with dilute sulfuric acid, anhydrous ethanol and carbon disulfide until the washing liquid becomes clear.

[0054] Comparative Example 1 Preparation of MOF

[0055] The preparation steps of the MOF of Comparative Example 1 are the same as step (1) in Example 1.

[0056] Comparative Example 2 Preparation of MOF@C

[0057] The preparation steps of MOF@C in Comparative Example 2 are the same as steps (1) and (2) in Example 1.

[0058] The FeS2-MOF@C prepared in Example 1, the MOF prepared in Comparative Example 1 and the MOF@C catalyst prepared in Comparative Example 2 were characterized, and the results are as follows:

[0059] Figure 1 The scanning electron microscope images of the FeS2-MOF@C prepared in Example 1, the MOF prepared in Comparative Example 1, and the MOF@C catalyst prepared in Comparative Example 2 show that the MOF prepared by the microwave method has a complete crystal form and a consistent structure, which confirms the advantages of the microwave synthesis method. It can be seen that MOF@C exhibits more pore structures after calcination, corresponding to a larger specific surface area. FeS2-MOF@C can clearly see that FeS2 is attached to the surface of MOF@C, confirming the successful synthesis of FeS2-MOF@C.

[0060] Figure 2 The XRD spectra of FeS2-MOF@C prepared in Example 1, MOF prepared in Comparative Example 1 and MOF@C catalysts prepared in Comparative Example 2 show that the diffraction peaks of FeS2 in the prepared FeS2-MOF@C are highly consistent with those of FeS2 (JCPDS 42-1340) in the XRD standard card. In the spectrum of FeS2, 2θ = 28.58°, 33.15°, 37.12°, 40.8°, 47.57°, 56.4°, 59.18°, 61.8°, 64.18°, corresponding to (111), (200), (210), (211), (220), (311), (222), (023) and (321) crystal planes, respectively, and the XRD spectrum of FeS2-MOF@C corresponds to the superimposed spectrum of FeS2 and MOF@C, confirming the successful synthesis of FeS2-MOF@C.

[0061] Example 2 Experiment of removing PFOA by electro-Fenton of FeS2-MOF@C catalyst

[0062] A three-electrode system was constructed, and the specific operation was as follows: graphite felt (GF / Cu) with copper electrodeposited was used as the working electrode (area 3×3.5cm), the deposition solution was 200mL of a mixed solution of 50mM and 0.5M CuSO4·5H2O and H2SO4, the deposition voltage was -0.6V, and the deposition time was 60s; the counter electrode was a 2×2cm BDD electrode; and the reference electrode was an Ag / AgCl electrode. The reaction conditions of the electro-Fenton reaction process were: the amount of catalyst was 0.4g / L, the applied voltage was -0.8V, the reaction time was 3 hours, the aeration rate was 2.5L / min, the electrolyte solution volume was 100mL, and the electrolyte was 0.1M Na2SO4. The heterogeneous Fenton catalyst and PFOA were added to the electrolyte to make the PFOA concentration 10mg / L, and ultrasound was used to disperse it evenly.

[0063] Example 3

[0064] The experimental operation steps of this example are the same as those of Example 2, except that the catalyst FeS2-MOF@C is replaced with MOF, MOF@C and FeS2 of equal mass.

[0065] In the above-mentioned Examples 2 and 3, the removal effects of different catalysts on PFOA are shown in FIG. Figure 3 The results showed that under the same mass, FeS2-MOF@C prepared by combining FeS2 and MOF@C had the best PFOA removal effect, which confirmed that the combination of the two catalysts can improve the catalytic effect and the necessity of the combination.

[0066] Example 4

[0067] The experimental operation steps of this example are the same as those of Example 2 except that the catalyst dosage is 0.1, 0.2, 0.3, and 0.5 g / L.

[0068] In the above-mentioned Example 2 and Example 4, the removal effect of PFOA by different catalyst dosages is shown in the figure Figure 4 The results show that the PFOA removal effect is best when the catalyst dosage is 0.4g / L and 0.5g / L, and the removal rates of the two are similar. In order to achieve higher economic benefits, the catalyst dosage of 0.4g / L was finally selected.

[0069] Example 5

[0070] The experimental operation steps of this embodiment are the same as those of embodiment 2, except that the applied voltages are -0.5V, -0.6V, -0.7V, -0.9V and -1.0V.

[0071] In the above-mentioned Example 2 and Example 5, the removal effect of PFOA at different voltages is shown in FIG. Figure 5 The results show that as the voltage increases, the PFOA removal rate gradually increases, and the PFOA removal rate is the highest at a voltage of -0.8V. As the voltage continues to increase, the side reaction rate of electrolyzing water to generate H2 and O2 increases, forming a competitive relationship with the main reaction of H2O2 generation. Therefore, the PFOA removal effect is relatively excellent at a voltage of -0.8V.

[0072] Example 6

[0073] The experimental operation steps of this example are the same as those of Example 2, except that the number of cycles of the FeS2-MOF@C catalyst is different.

[0074] In the above-mentioned Example 2 and Example 6, the effect of different recycling times of FeS2-MOF@C catalyst on the removal of PFOA and the defluorination rate are shown in the figure Figure 6The results showed that when used for the first time, the removal rate of PFOA was 100% within 3 hours, and the defluorination rate was 76%; after three cycles of use, the removal rate was still 94% and the defluorination rate was 71%; when used for the fourth time, the removal rate was 87% and the defluorination rate was 67%, indicating that the system has good stability.

[0075] Comparative Example 3

[0076] The experimental operation steps of this example are the same as those of Example 2, except that the counter electrode is replaced by a platinum (Pt) electrode of the same area from a BDD electrode.

[0077] In the above Example 2 and Comparative Example 3, the removal effect of PFOA by different electrodes is shown in FIG. Figure 7 The results show that under the same conditions, the removal effect of Pt electrode on PFOA is much smaller than that of BDD electrode. This is attributed to the fact that BDD electrode can be used to capture the electrons of PFOA carboxyl group, and then make the unstable carboxyl group separate from PFOA and turn into CO2, which is beneficial to the degradation of active oxygen species produced by the decomposition of PFOA by H2O2. The pt electrode cannot achieve this process, which confirms the role of BDD electrode in this electro-Fenton degradation system.

[0078] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for synthesizing a heterogeneous Fenton catalyst, It is characterized in that The following steps are involved: (1) calcining the MOF material in a non-oxidizing atmosphere to obtain a carbonized MOF material; (2) Using the carbonized MOF material obtained in step (1) as a template, FeSO 4、 Na 2 S 2 O 3 and sulfur as raw materials, FeS was synthesized by hydrothermal method. 2 , that is, a heterogeneous Fenton catalyst with carbonized MOF material as template is obtained.

2. The method for synthesizing the heterogeneous Fenton catalyst according to claim 1, It is characterized in that In step (1), the MOF material is prepared by a microwave method.

3. The method for synthesizing the heterogeneous Fenton catalyst according to claim 2, It is characterized in that The synthesis conditions of the microwave method are as follows: time 20-40 minutes, power 50-150W / tank, and temperature 100-140°C.

4. The method for synthesizing the heterogeneous Fenton catalyst according to claim 1, It is characterized in that In step (1), the MOF material is MOF-74 material, which is made of raw material FeSO 4 7H 2 O and 2,5-dihydroxyterephthalic acid.

5. The method for synthesizing the heterogeneous Fenton catalyst according to claim 1, It is characterized in that In step (1), the calcination temperature is 400-600°C, the heating rate is 4-6°C / min, and the heat preservation time is 1-3 hours.

6. A heterogeneous Fenton catalyst prepared according to any one of claims 1 to 5.

7. Use of the heterogeneous Fenton catalyst as claimed in claim 6 for degrading polyfluorinated and / or perfluorinated compounds.

8. The use according to claim 7, It is characterized in that The application is the degradation and removal of polyfluorinated and / or perfluorinated organic pollutants by the three-electrode system electro-Fenton method.

9. The use according to claim 8, It is characterized in that The application is specifically: using copper-deposited graphite felt as a working electrode, a boron-doped diamond electrode as a counter electrode, an Ag / AgCl electrode as a reference electrode, and Na 2 SO 4 As an electrolyte, the heterogeneous Fenton catalyst and the pollutant are added to the electrolyte for dispersion; the working electrode is used to reduce O in the aqueous solution. 2 Output H 2 O 2 The heterogeneous Fenton catalyst is used to accelerate H 2 O 2 Decomposition, thereby catalyzing the generation of more active oxygen species, achieving efficient degradation of the pollutants.

10. The use according to claim 8 or 9, It is characterized in that The mass volume ratio of the heterogeneous Fenton catalyst to the electrolyte divided by the concentration of the organic pollutant is 30-60; the voltage applied by the electro-Fenton method is -0.5 to -1.0 V, the reaction time is less than 3 hours, and the aeration rate is 2.5 L / min.

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