Electrode preparation method of a bioelectrochemical device and application thereof

Abstract

The application discloses a kind of electrode preparation method of bioelectrochemical equipment and application thereof, method includes the following steps: S1, pretreatment;S2, polyvinyl alcohol solution preparation;S3, electrode slurry preparation;S4, coating;S5, drying.The electrode is used to handle chlorophenol wastewater.The electrode of the application is prepared by zero-valent iron modification, and is arranged in the anode region of bioelectrochemical reactor, can effectively control oxidation-reduction potential by loading trace zero-valent iron, strengthens the electron transfer between iron-reducing bacteria and acetogenic bacteria in anode, enriches acetogenic bacteria group, to improve acid production of acid phase acetate, realizes simultaneous pollutant removal and methane production increase, improves economic benefit.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a method for preparing electrodes for a bioelectrochemical device and its application. Background Technology

[0002] In my country, high-concentration organic wastewater accounts for approximately 20% of total industrial wastewater discharge, with its chemical oxygen demand (COD) typically exceeding 2000 mg / L. Chlorophenols, as common persistent pollutants in this type of wastewater, are widely derived from the pharmaceutical, pesticide, paint, and chemical industries. These substances not only have poor biodegradability and high biological toxicity but are also difficult to treat, making them one of the challenges in wastewater treatment.

[0003] In existing technologies, two-phase anaerobic electrofermentation systems have been attempted to enhance the degradation of organic pollutants. For example, Chinese patent application CN118005187A proposes a method for applying a two-phase anaerobic electrofermentation device. By setting the anode in the acid-producing phase and the cathode in the methanogenic phase, and applying an external electric field, the proton and electron utilization efficiency is improved, thereby promoting the degradation of chlorophenols. However, this technology still has certain limitations in practical applications: on the one hand, it easily generates toxic intermediates when treating polychlorophenols, causing secondary pollution; on the other hand, the degradation efficiency for monochlorophenols (such as p-chlorophenol) still needs further improvement.

[0004] Zero-valent iron (ZVFe), a commonly used electrode modifier and microbial enhancement material, is frequently introduced into bioelectrochemical systems to enhance the reductive dechlorination process. Since the degradation of chlorophenols depends on electron-gaining reactions, current technologies primarily focus on cathode modification or the addition of ZVFe as an electron donor at the cathode. While these methods can promote dechlorination to some extent, they still have significant drawbacks, including high iron dosages, iron ion accumulation in the microbial community inhibiting biological activity, and excessive iron content in the effluent. These issues not only increase operating costs but may also negatively impact the subsequent aquatic environment. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing electrodes for a bioelectrochemical device and its application.

[0006] The technical solution of this invention is:

[0007] A method for preparing an electrode for a bioelectrochemical device includes the following steps:

[0008] S1. Pretreatment: Soak the carbon felt in ethanol and acetone in sequence, then wash it with pure water and dry it for later use.

[0009] S2. Preparation of polyvinyl alcohol solution: Mix polyvinyl alcohol with deionized water, heat and stir until completely dissolved to prepare a polyvinyl alcohol solution, wherein the polyvinyl alcohol content is 1~10 wt%;

[0010] S3. Electrode slurry preparation: Zero-valent iron is added to the polyvinyl alcohol solution and shaken evenly to prepare an electrode slurry, wherein the content of zero-valent iron is 5~20 wt%;

[0011] S4. Coating: The electrode slurry is uniformly coated onto the pretreated carbon felt surface;

[0012] S5. Drying: The coated carbon felt is dried under anaerobic conditions, and the carbon felt is kept in a rotating state during the drying process. The electrode of the bioelectrochemical device is obtained after the drying is completed.

[0013] Furthermore, in S1, the carbon felt has a size of 1~3cm×1~3cm×0.2~0.6cm, an ethanol soaking time of 12±0.5h, and an acetone soaking time of 24±1h.

[0014] Note: By properly controlling the electrode size, the treatment effect on sludge can be ensured. Electrodes that are too large will occupy space in the bioelectrochemical reactor and are complicated to manufacture. Electrodes that are too small will have a small contact area with the sludge, which will weaken the influence of the electric field on the sludge.

[0015] Furthermore, in S2, the degree of alcoholysis of the polyvinyl alcohol is 89-99%, the heating temperature is 90-100℃, the heating time is 0.5-2h, and the stirring frequency is 500-700rpm.

[0016] Note: When the degree of alcoholysis is below 89%, polyvinyl alcohol will dissolve directly in water, making it difficult to fix zero-valent iron on the carbon felt. When the degree of alcoholysis is high, polyvinyl alcohol only dissolves in hot water above 95°C, and will not dissolve in the reactor during use.

[0017] Furthermore, in S3, the shaking frequency is 100~200rpm, and the shaking time is 1~4h.

[0018] Note: Ensure uniform mixing of the electrode slurry by properly controlling the shaking frequency and time.

[0019] Furthermore, in S4, the amount of electrode slurry used during coating is 100~200 μL / cm. 2 .

[0020] Note: Too little electrode slurry will make it difficult to evenly cover the entire carbon felt electrode, resulting in excessively high zero-valent iron content in some areas; while too much electrode slurry will not only lead to excessively long drying time, but also cause too much polyvinyl alcohol solution to be thrown off during rotation, reducing the actual zero-valent iron load on the carbon felt.

[0021] Furthermore, in S5, the oxygen-free conditions are carried out in a nitrogen drying oven at a temperature of 50~80℃ for 6~10h and a rotation speed of 15~35rpm.

[0022] Note: Maintaining an oxygen-free environment prevents iron on the high-temperature carbon felt from converting into iron oxides.

[0023] The present invention also provides an application of an electrode for a bioelectrochemical device, which is prepared based on the above-described method for preparing an electrode for a bioelectrochemical device, and the electrode is used to treat chlorophenol wastewater.

[0024] Furthermore, the method for using the electrode to treat chlorophenol wastewater is as follows:

[0025] (1) Install the electrode as the anode of the bioelectrochemical reactor and introduce water containing chlorophenols into the bioelectrochemical reactor;

[0026] (2) Chlorinated phenolic substances are injected into the bottom of the anode chamber of the bioelectrochemical reactor and overflow into the cathode chamber. Then they flow out through the outlet on the upper side wall of the cathode chamber. The influent flow rate is 500~1500μL / min and the hydraulic residence time is 12±1h. A regulated DC power supply is used to provide a 2V voltage, resulting in a current of 0.5~1.5mA.

[0027] Note: By reasonably controlling parameters such as hydraulic retention time and influent flow rate, the treatment efficiency can be improved while ensuring the treatment effect of the bioelectrochemical reactor.

[0028] Furthermore, the volume of the bioelectrochemical reactor is 600~800mL.

[0029] Explanation: By rationally controlling the volume of the bioelectrochemical reactor, the treatment efficiency can be improved while ensuring the treatment effect of the bioelectrochemical reactor.

[0030] The beneficial effects of this invention are:

[0031] The electrode preparation method of this invention uses zero-valent iron (ZCE) to prepare the electrode, which is then placed in the anode region of a bioelectrochemical reactor. By loading a trace amount of ZCE, the redox potential can be effectively controlled, enhancing electron transfer between iron-reducing bacteria and acetic acid-producing bacteria at the anode, enriching the acetic acid-producing bacterial population, and thus increasing the acetic acid yield in the acid-producing phase. After high-concentration acetic acid enters the methanogenic phase, it can further enrich acetic acid-preferring methanogenic bacteria. The coenzyme F430 contained in these microorganisms can not only lower the dechlorination energy barrier but also endow methanogenic bacteria with a certain direct dechlorination ability. Under the action of the electric field, the iron ions generated by the zero-valent electrochemical corrosion at the anode migrate to the cathode and generate iron hydroxyl oxide in situ. This substance not only has a good chemical adsorption capacity for chlorophenol pollutants but also increases the abundance of dehalogenated cocci in the methanogenic phase, effectively enriching the target pollutants and enhancing their bioavailability. This comprehensively improves the degradation efficiency of chlorophenols and the stability of the system, achieving simultaneous pollutant removal and increased methane production, thereby improving economic benefits.

[0032] The electrode preparation method of the present invention adds an electrode rotation step during the drying process. In the existing coating method for modifying electrodes, due to the long period of static setting during the drying process, the substances in the electrode slurry often settle in the early stage of drying, especially zero-valent iron powder, which is prone to agglomeration and loss of original activity. By keeping it rotated during the drying process, the activity loss caused by the drying process can be minimized.

[0033] (3) When the electrode prepared by the electrode preparation method of the present invention is used to treat chlorophenol wastewater, the zero-valent iron on the electrode improves the electrode's ability to capture electrons in the environment, so that excess electrons are effectively transferred to the cathode, which effectively improves the current output capability of the bioelectrochemical system and improves economic benefits. Attached Figure Description

[0034] Figure 1 This is a process flow diagram of the electrode preparation method of the present invention;

[0035] Figure 2 This is a schematic diagram of the electrode surface in Experiment Example 1;

[0036] Figure 3 This is a schematic diagram of the electrode surface in Experiment Example 2;

[0037] Figure 4 These are XRD test and analysis images of the anode electrode in three sets of experimental examples;

[0038] Figure 5 These are XRD test and analysis images of the cathode electrodes in three sets of experimental examples;

[0039] Figure 6 This is a SEM image of the carbon felt before loading in Experiment Example 2;

[0040] Figure 7This is a SEM image of the loaded carbon felt in Experiment Example 2;

[0041] Figure 8 The degradation rates of chlorophenol in the reactors of Experimental Example 1 and Experimental Example 2 are shown.

[0042] Figure 9 This is a diagram showing the methanogenic effect of the electrode in Experiment Example 2;

[0043] Figure 10 This is a schematic diagram showing the amount of p-chlorophenol generated in Experiment Example 3;

[0044] Figure 11 The concentration of VFAs in the acid phase effluent within two weeks after 10 days of reactor reaction in Experimental Examples 1 and 2.

[0045] Figure 12 This is a schematic diagram of the bioelectrochemical reactor of the present invention. Detailed Implementation

[0046] Example 1: A method for preparing electrodes for a bioelectrochemical device, such as... Figure 1 As shown, it includes the following steps:

[0047] S1. Pretreatment: Soak the carbon felt in ethanol and acetone in sequence, then wash it with pure water, and dry it for later use. The carbon felt size is 2cm×2cm×0.3cm. The ethanol soaking time is 12h and the acetone soaking time is 24h.

[0048] S2. Preparation of polyvinyl alcohol solution: Polyvinyl alcohol is mixed with deionized water and heated and stirred until completely melted to prepare a polyvinyl alcohol solution. The polyvinyl alcohol content is 5 wt%, the degree of alcoholysis of polyvinyl alcohol is 95%, the heating temperature is 98℃, the heating time is 1 h, and the stirring frequency is 700 rpm.

[0049] S3. Electrode slurry preparation: Zero-valent iron is added to a polyvinyl alcohol solution and shaken evenly to prepare an electrode slurry. The zero-valent iron content is 5wt%, the shaking frequency is 180rpm, and the shaking time is 2h.

[0050] S4. Coating: Apply the electrode slurry evenly to the pretreated carbon felt surface. The amount of electrode slurry used during coating is 150 μL / cm². 2 ;

[0051] S5. Drying: The coated carbon felt is dried under anaerobic conditions. During the drying process, the carbon felt is kept rotating. The electrode of the bioelectrochemical device is obtained after drying, denoted as Fe@CFF-1. The anaerobic conditions are carried out in a nitrogen drying oven at a temperature of 60℃ for 8 hours and a rotation speed of 30 rpm.

[0052] Example 2: A method for preparing an electrode for a bioelectrochemical device, comprising the following steps:

[0053] S1. Pretreatment: Soak the carbon felt in ethanol and acetone in sequence, then wash it with pure water, and dry it for later use. The carbon felt size is 2cm×2cm×0.3cm. The ethanol soaking time is 12h and the acetone soaking time is 24h.

[0054] S2. Preparation of polyvinyl alcohol solution: Polyvinyl alcohol is mixed with deionized water and heated and stirred until completely melted to prepare a polyvinyl alcohol solution. The polyvinyl alcohol content is 10 wt%, the degree of alcoholysis of polyvinyl alcohol is 95%, the heating temperature is 98℃, the heating time is 1 h, and the stirring frequency is 700 rpm.

[0055] S3. Electrode slurry preparation: Zero-valent iron is added to a polyvinyl alcohol solution and shaken evenly to prepare an electrode slurry. The zero-valent iron content is 10wt%, the shaking frequency is 180rpm, and the shaking time is 2h.

[0056] S4. Coating: Apply the electrode slurry evenly to the pretreated carbon felt surface. The amount of electrode slurry used during coating is 150 μL / cm². 2 ;

[0057] S5. Drying: The coated carbon felt is dried under anaerobic conditions. During the drying process, the carbon felt is kept rotating. After drying, the electrode of the bioelectrochemical device is obtained, denoted as Fe@CFF-2. The anaerobic conditions are carried out in a nitrogen drying oven at a temperature of 60℃ for 8 hours and a rotation speed of 30 rpm.

[0058] Example 3: A method for preparing an electrode for a bioelectrochemical device, comprising the following steps:

[0059] S1. Pretreatment: Soak the carbon felt in ethanol and acetone in sequence, then wash it with pure water, and dry it for later use. The carbon felt size is 2cm×2cm×0.3cm. The ethanol soaking time is 12h and the acetone soaking time is 24h.

[0060] S2. Preparation of polyvinyl alcohol solution: Polyvinyl alcohol is mixed with deionized water and heated and stirred until completely melted to prepare a polyvinyl alcohol solution. The polyvinyl alcohol content is 10 wt%, the degree of alcoholysis of polyvinyl alcohol is 95%, the heating temperature is 98℃, the heating time is 1 h, and the stirring frequency is 700 rpm.

[0061] S3. Electrode slurry preparation: Zero-valent iron is added to a polyvinyl alcohol solution and shaken evenly to prepare an electrode slurry. The zero-valent iron content is 20wt%, the shaking frequency is 180rpm, and the shaking time is 2h.

[0062] S4. Coating: Apply the electrode slurry evenly to the pretreated carbon felt surface. The amount of electrode slurry used during coating is 150 μL / cm². 2 ;

[0063] S5. Drying: The coated carbon felt is dried under anaerobic conditions. During the drying process, the carbon felt is kept rotating. After drying, the electrode of the bioelectrochemical device is obtained, denoted as Fe@CFF-3. The anaerobic conditions are carried out in a nitrogen drying oven at a temperature of 60℃ for 8 hours and a rotation speed of 30 rpm.

[0064] Example 4: The difference between this example and Example 1 is that in S1, the carbon felt size is 1cm×1cm×0.2cm, the ethanol soaking time is 11.5h, and the acetone soaking time is 23h.

[0065] Example 5: The difference between this example and Example 1 is that in S1, the carbon felt size is 3cm×3cm×0.6cm, the ethanol soaking time is 12.5h, and the acetone soaking time is 25h.

[0066] Example 6: This example differs from Example 1 in that, in S2, the polyvinyl alcohol content is 1 wt%, the degree of alcoholysis of polyvinyl alcohol is 89%, the heating temperature is 90°C, the heating time is 2 h, and the stirring frequency is 700 rpm.

[0067] Example 7: The difference between this example and Example 1 is that in S2, the polyvinyl alcohol content is 8wt%, the degree of alcoholysis of polyvinyl alcohol is 99%, the heating temperature is 100℃, the heating time is 0.5h, and the stirring frequency is 500rpm.

[0068] Example 8: The difference between this example and Example 1 is that in S3, the shaking frequency is 200 rpm and the shaking time is 1 hour.

[0069] Example 9: The difference between this example and Example 1 is that in S3, the shaking frequency is 100 rpm and the shaking time is 4 hours.

[0070] Example 10: This example differs from Example 1 in that, in S4, the amount of electrode slurry used during coating is 100 μL / cm. 2 .

[0071] Example 11: This example differs from Example 1 in that, in S4, the amount of electrode slurry used during coating is 200 μL / cm. 2 .

[0072] Example 12: The difference between this example and Example 1 is that in S5, the drying temperature is 50°C, the drying time is 10 hours, and the rotation speed is 15 rpm.

[0073] Example 13: The difference between this example and Example 1 is that in S5, the drying temperature is 80°C, the drying time is 6 hours, and the rotation speed is 35 rpm.

[0074] Example 14: This example provides an application of an electrode for a bioelectrochemical device, prepared based on the electrode preparation method for a bioelectrochemical device in Example 1. The electrode is used to treat chlorophenol wastewater, such as... Figure 12 As shown, the method is as follows:

[0075] (1) Install the electrode as the anode of the bioelectrochemical reactor, and introduce water containing chlorophenols into the bioelectrochemical reactor. The allowable concentration range of pollutants in the water to be treated is 0~200mg / L, and the allowable COD range of the influent is 1500~3000mg / L. The bioelectrochemical reactor is a commercially available model of the P61-45 reactor.

[0076] (2) Chlorinated phenolic water is injected from the bottom of the anode chamber of the bioelectrochemical reactor and overflows into the cathode chamber. It then flows out through the outlet on the upper side wall of the cathode chamber. The influent flow rate is 1000 μL / min, the hydraulic retention time is 12h, and a regulated DC power supply is used to provide a 2V voltage, resulting in a current of 1mA. The volume of the bioelectrochemical reactor is 700mL.

[0077] After the bioelectrochemical reactor had been running for 5 days, the cathode electrode was examined to confirm the formation of iron oxide. The cathode electrode was examined by XRD.

[0078] The concentration of VFAs in the anolyte was measured on the 25th day of operation of the bioelectrochemical reactor, and the concentration of VFAs in the anolyte effluent was measured again on the 55th day of operation of the bioelectrochemical reactor. If the concentration of VFAs measured in the second measurement was more than twice that measured in the first measurement, the enhanced organic acidification of the anolyte was confirmed.

[0079] Take water from the bioelectrochemical reactor and determine the concentration of chlorophenols in it.

[0080] Example 15: This example differs from Example 14 in that the influent flow rate is 500 μL / min, the hydraulic retention time is 11 h, a regulated DC power supply is used to provide a 2V voltage, resulting in a current of 0.5 mA, and the volume of the bioelectrochemical reactor is 600 mL.

[0081] Example 16: This example differs from Example 14 in that the influent flow rate is 1500 μL / min, the hydraulic retention time is 13 h, a regulated DC power supply is used to provide a 2 V voltage, resulting in a current of 1.5 mA, and the volume of the bioelectrochemical reactor is 800 mL.

[0082] Example 17: The difference between this example and Example 14 is that after the bioelectrochemical reactor has been running for 3 days, the cathode electrode was tested to confirm the formation of iron oxides. The method for testing the cathode electrode is to detect the difference in total iron concentration between the anode effluent and the cathode effluent. If there is no XRD detection condition, the difference in total iron concentration between the anode effluent and the cathode effluent can be detected. When the total iron concentration in the anode effluent is stable at more than twice the total iron concentration in the cathode effluent, the formation of iron oxides can be confirmed.

[0083] Example 18: The difference between this example and Example 14 is that, in S-III: after the bioelectrochemical reactor has been running for 10 days, the cathode electrode was tested to confirm the formation of iron oxide. The method for detecting the cathode electrode was XRD detection. When XRD detection conditions are available, XRD spectral analysis can be performed directly. If there is an obvious FeOOH characteristic peak, the formation of FeOOH can be confirmed.

[0084] Example 19: This example differs from Example 14 in that the concentration of VFAs in the anolyte is measured on the 20th day of operation of the bioelectrochemical reactor, and the concentration of VFAs in the anolyte effluent is measured again on the 50th day of operation of the bioelectrochemical reactor. If the concentration of VFAs measured in the second measurement is more than twice the concentration of VFAs measured in the first measurement, then the enhanced organic acidification of the anolyte is confirmed.

[0085] Example 20: This example differs from Example 14 in that the concentration of VFAs in the anolyte is measured on the 30th day of operation of the bioelectrochemical reactor, and the concentration of VFAs in the anolyte effluent is measured again on the 60th day of operation of the bioelectrochemical reactor. If the concentration of VFAs measured in the second measurement is more than twice the concentration of VFAs measured in the first measurement, then the enhanced organic acidification of the anolyte is confirmed.

[0086] Example 21: The difference between this example and Example 14 is that the bioelectrochemical reactor is a commercially available H-type microbial fuel cell reactor.

[0087] Experimental Example 1: The electrode material prepared by the method in Example 1 was tested. It appeared as a black block with transparent or white flashes on one side and a porous internal structure. Figure 2 As shown; the loading after digestion, measured by ICP, was approximately 5 mg / cm³. 2 This indicates successful quantitative loading; XRD analysis of the sample yielded the following results. Figure 4 As shown, the characteristic peaks of zero-valent iron are observed, confirming that iron exists in the form of zero-valent iron. XRD analysis of the cathode was performed 10 days after the reaction, and the results are as follows... Figure 5 As shown, the peak of hydroxyl iron oxide is displayed, confirming that hydroxyl iron oxide is generated in situ at the cathode.

[0088] The degradation effect of Fe@CFF-1 on chlorophenol in a two-phase anaerobic electrofermentation reactor was tested, with a carbon felt electrode (named CFF) without loading as a comparison.

[0089] like Figure 8 As shown, the degradation rate of chlorophenol in the reactor using CFF electrode is about 30%, while the degradation rate of chlorophenol in the reactor using Fe@CFF-1 electrode is about 50%, which effectively improves the degradation rate of chlorophenol.

[0090] like Figure 11 As shown, the concentration of VFAs in the acidic phase effluent was measured within two weeks after 10 days of reaction. The acetic acid concentration in the reactor using the Fe@CFF-1 electrode was significantly higher than that in the reactor using the CFF electrode, confirming the enhancing effect of Fe@CFF-1 on the acidification process.

[0091] Experimental Example 2: The electrode material prepared by the method in Example 2 was tested. It appeared as a black block with transparent or white flashes on one side and a porous internal structure. Figure 3 As shown; the loading after digestion, measured by ICP, was approximately 10 mg / cm³. 2 This indicates successful quantitative loading; SEM tests were performed on the carbon felt before and after loading, respectively. Before loading, as shown... Figure 6 As shown, after load, as Figure 7 As shown in the figure, a fibrous porous structure can be clearly seen inside the carbon felt, and this porous structure remains even after loading, although there are obvious deposits on the surface of the carbon felt filaments; XRD analysis of the fabricated electrode yields the following results. Figure 4 As shown, the characteristic peaks of zero-valent iron are observed, confirming that iron exists in the form of zero-valent iron. XRD analysis of the cathode was performed 10 days after the reaction, and the results are as follows... Figure 5 As shown, the peak of hydroxyl iron oxide is displayed, confirming that hydroxyl iron oxide is generated in situ at the cathode.

[0092] The degradation effect of Fe@CFF-2 on chlorophenol in a two-phase anaerobic electrofermentation reactor was tested, with a carbon felt electrode (named CFF) without loading as a comparison.

[0093] like Figure 8 As shown, the reactor using Fe@CFF-2 electrodes achieved a chlorine degradation rate exceeding 80%, effectively improving chlorophenol degradation. The methanogenesis effect is as follows... Figure 9 As shown, the methane yield of the reactor using CFF electrodes is only about 0.55%, while the methane yield of the reactor using Fe@CFF-2 electrodes is about 1.2%, which effectively improves the methane yield.

[0094] like Figure 11As shown, the concentration of VFAs in the acidic phase effluent was measured within two weeks after 10 days of reaction. The acetic acid concentration in the reactor using the Fe@CFF-2 electrode was significantly higher than that in the reactors using the CFF electrode and the Fe@CFF-1 electrode, confirming that the enhancing effect of the prepared electrode on the acidification process is related to the iron loading content.

[0095] Compared to application example 1, Fe@CFF-2 has a higher and more stable iron loading, thus resulting in better removal of chlorophenol.

[0096] Experimental Example 3: The electrode material prepared by the method in Example 3 was tested. It appeared as a black block, and after digestion, the loading measured by ICP was approximately 20 mg / cm³. 2 This indicates successful quantitative loading; XRD analysis of the sample yielded the following results. Figure 4 As shown, the characteristic peaks of zero-valent iron are observed, confirming that iron exists in the form of zero-valent iron. XRD analysis of the cathode was performed 10 days after the reaction, and the results are as follows... Figure 5 As shown, the peak of hydroxyl iron oxide is displayed, confirming that hydroxyl iron oxide is generated in situ at the cathode.

[0097] The effect of Fe@CFF-3 on the formation of toxic byproducts (p-chlorophenol) during the degradation of 2,4-dichlorophenol in a two-phase anaerobic electrofermentation reactor was tested. A carbon felt electrode without loading (named CFF) was used as a comparison. The concentration of 2,4-dichlorophenol in the influent was 100 mg / L.

[0098] Whether using the Fe@CFF-3 electrode or the CFF electrode, both exhibit a high degradation rate (around 99%) for 2,4-dichlorophenol, but... Figure 10 As shown, the reactor using the Fe@CFF-3 electrode produced approximately 32 mg / L of p-chlorophenol, while the reactor using the CFF electrode produced approximately 84 mg / L. This confirms that the prepared electrode can effectively reduce the generation of toxic byproducts during the degradation of polychlorinated phenols.

Claims

1. The application of an electrode in a bioelectrochemical device, characterized in that, The electrode preparation method includes the following steps: S1. Pretreatment: Soak the carbon felt in ethanol and acetone in sequence, then wash it with pure water and dry it for later use. S2. Preparation of polyvinyl alcohol solution: Polyvinyl alcohol is mixed with deionized water and heated and stirred until completely melted to prepare a polyvinyl alcohol solution, wherein the polyvinyl alcohol content is 1~10wt%, the degree of alcoholysis of the polyvinyl alcohol is 89~99%, the heating temperature is 90~100℃, the heating time is 0.5~2h, and the stirring frequency is 500~700rpm. S3. Electrode slurry preparation: Zero-valent iron is added to the polyvinyl alcohol solution and shaken evenly to prepare an electrode slurry, wherein the content of zero-valent iron is 5~20 wt%; S4. Coating: The electrode slurry is uniformly coated onto the pretreated carbon felt surface; S5. Drying: The coated carbon felt is dried under anaerobic conditions. During the drying process, the carbon felt is kept in a rotating state. The electrode of the bioelectrochemical device is obtained after the drying is completed. The electrode is used to treat chlorophenol wastewater; The method for using the electrode to treat chlorophenol wastewater is as follows: (1) Install the electrode as the anode of the bioelectrochemical reactor and introduce water containing chlorophenols into the bioelectrochemical reactor; (2) Chlorinated phenolic substances are injected into the bottom of the anode chamber of the bioelectrochemical reactor and overflow into the cathode chamber. Then they flow out through the outlet on the upper side wall of the cathode chamber. The influent flow rate is 500~1500μL / min and the hydraulic residence time is 12±1h. A regulated DC power supply is used to provide a 2V voltage, resulting in a current of 0.5~1.5mA.

2. The application of the electrode of the bioelectrochemical device according to claim 1, characterized in that, In S1, the carbon felt has a size of 1~3cm×1~3cm×0.2~0.6cm, an ethanol soaking time of 12±0.5h, and an acetone soaking time of 24±1h.

3. The application of the electrode of the bioelectrochemical device according to claim 1, characterized in that, In S3, the shaking frequency is 100~200rpm and the shaking time is 1~4h.

4. The application of the electrode of the bioelectrochemical device according to claim 1, characterized in that, In step S4, the amount of electrode slurry used during coating is 100~200 μL / cm. 2 .

5. The application of the electrode of the bioelectrochemical device according to claim 1, characterized in that, In S5, the oxygen-free conditions are carried out in a nitrogen drying oven at a temperature of 50~80℃ for 6~10 hours and a rotation speed of 15~35 rpm.

6. The application of the electrode of the bioelectrochemical device according to claim 1, characterized in that, The volume of the bioelectrochemical reactor is 600~800mL.

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