Oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection and preparation method thereof

Abstract

The invention discloses a high-sensitivity oxygen-resistant anode MFC (Microbial Fuel Cell) sensor for biotoxicity detection and a preparation method thereof. The sensor comprises a positive electrode, a negative electrode, a positive electrode chamber, a negative electrode chamber, a diaphragm, a current loop and a data acquisition system, a double-layer biological membrane is formed on the positive electrode through aerobic domestication, the outer layer is an aerobic bacteria layer, and the inner layer is an anaerobic electroactive bacteria layer. The aerobic bacteria on the outer layer consume dissolved oxygen and provide a stable environment for the anaerobic bacteria on the inner layer, so that the oxygen resistance and the operation stability of the sensor are remarkably improved. When the toxicity of a to-be-detected sample is detected, the biotoxicity of the sample is represented through the electrogenesis inhibition rate of the sensor. Experiments show that the response sensitivity of the sensor to toxic substances (such as Cu (II)) is obviously higher than that of a traditional anaerobic MFC sensor, and the sensor shows excellent anti-interference capability under different dissolved oxygen conditions. The method is suitable for rapid detection of biotoxicity of water and environmental samples, and has the characteristics of high sensitivity, strong oxidation interference resistance and good stability.

Description

Technical Field

[0001] This invention relates to the field of biosensor technology, and in particular to a high-sensitivity oxygen-resistant anodic microbial fuel cell (MFC) sensor for detecting biotoxicity and its preparation method. Background Technology

[0002] Biotoxicity monitoring of water and environmental samples is crucial for early warning of water pollution and for protecting public health and safety. Traditional biotoxicity detection methods, such as algae, fish, and luminescent bacteria tests, can reflect the comprehensive toxic effects of pollutants, but they are complex, time-consuming, and costly. Physicochemical analysis methods, such as chromatography and mass spectrometry, offer rapid responses, but can only detect specific known pollutants. Microbial fuel cell (MFC) is an emerging bioelectrochemical technology that utilizes electroactive microorganisms to catalyze the oxidation of organic matter and generate electricity, and its application in biotoxicity detection has been expanded in recent years.

[0003] Compared to traditional methods, MFC biotoxicity sensors exhibit potential advantages such as simple structure, relatively fast response, no need for external power supply, and ease of integration and in-situ online monitoring. They have already been applied in environmental monitoring scenarios such as biochemical oxygen demand (BOD) monitoring and heavy metal toxicity early warning. However, MFC biotoxicity sensors also face two major challenges in practical applications: dissolved oxygen interference and insufficient sensitivity. Traditional MFC anodes rely on electrogenic microorganisms, which are mostly strict anaerobic bacteria, and their electrogenic processes are easily inhibited in oxygen-containing environments. The sensitivity of existing sensors is limited by the oxygen tolerance and electron transfer efficiency of the microbial community, resulting in weak response signals to low concentrations of toxic substances, making it difficult to meet early warning requirements. It is worth noting that traditional domestication processes typically only enrich electrogenic bacteria under anaerobic conditions. Although some studies have attempted to improve the oxygen tolerance of the anode, their goals are limited to enhancing operational stability, neglecting to actively optimize toxicity response performance through targeted domestication strategies (such as aerobic condition regulation). This limitation in technical approach makes it difficult for existing solutions to synergistically improve environmental adaptability and detection sensitivity.

[0004] Therefore, to address the aforementioned problems, this invention proposes a high-sensitivity oxygen-resistant anode MFC sensor for biotoxicity detection and its fabrication method. This overcomes the sensitivity issue of traditional MFC sensors to dissolved oxygen interference and further improves the sensor's detection sensitivity for biotoxic substances while overcoming dissolved oxygen interference. Summary of the Invention

[0005] The present invention aims to provide a high-sensitivity oxygen-resistant anode MFC sensor for biotoxicity detection and its manufacturing method, so as to solve the problems of low sensitivity and susceptibility to oxygen interference when existing MFC sensors detect biotoxicity.

[0006] To achieve the above objectives, the present invention provides the following technical solution, the specific process of which is as follows:

[0007] S1. Construct an MFC sensor. The MFC sensor includes an anode chamber, an anode injection system, a diaphragm, a cathode chamber, a cathode injection system, a current loop, and a data acquisition system. The diaphragm is placed between the anode chamber and the cathode chamber. An anode electrode is placed in the anode chamber, and a cathode electrode is placed in the cathode chamber. The anode electrode and the cathode electrode are connected in series by wires to form a current loop. The anode injection system is used to deliver anolyte and the water sample to be tested into the anode chamber. The cathode injection system is used to deliver catholyte into the cathode chamber. The data acquisition system is used to acquire electrical signals.

[0008] S2. Acclimation of the oxygen-resistant anode MFC sensor. An oxygen-resistant anode with a double-layer biofilm structure was obtained through an aerobic acclimation method. The outer and inner layers of the double biofilm are aerobic bacteria and anaerobic electroactive bacteria, respectively. The aerobic bacteria in the outer layer consume oxygen in the water sample or test sample, maintaining the stability of the MFC sensor under different dissolved oxygen conditions. At the same time, under the influence of toxic pollutants, the aerobic activity of the outer layer aerobic bacteria is inhibited, leading to an increase in the amount of oxygen diffused into the inner layer of the biofilm. The electrogenic activity of the inner layer anaerobic electroactive bacteria is synergistically inhibited by oxygen and toxic pollutants, thereby improving the sensitivity of the oxygen-resistant anode MFC sensor in detecting toxic pollutants.

[0009] S3. Detecting the biotoxicity of water or environmental samples using an oxygen-resistant anode MFC sensor. The water or environmental sample to be tested is pumped into the anode chamber of the oxygen-resistant anode MFC sensor at a constant flow rate using an anode injection system. After running for a certain period, the biotoxicity of the water or environmental sample is characterized by the electrostatic inhibition rate of the oxygen-resistant anode MFC sensor.

[0010] Furthermore, the membrane in S1 is a cation exchange membrane, an anion exchange membrane, or a bipolar membrane.

[0011] Furthermore, in S1, the anode electrode is an electrode that is conducive to the attachment of microorganisms, such as carbon felt, carbon brush, carbon particles, or carbon cloth; the cathode electrode is a stable electrode that is conducive to oxygen reduction, such as stainless steel mesh, platinum electrode, carbon felt, carbon brush, or carbon cloth; the reference electrode is set near the anode electrode to monitor the potential of the anode electrode, and the reference electrode is an Ag / AgCl electrode or a saturated calomel electrode.

[0012] Further, the anode sampling system in S1 includes anolyte, an anolyte inlet pump, an anolyte gas pump, a water sample to be tested, a water sample inlet pump, and a water sample gas pump. The anolyte inlet pump and the water sample inlet pump are connected in parallel through the anode inlet to pump the anolyte and the water sample to be tested into the anode chamber at a constant flow rate, with the flow rate ratio of anolyte to water sample set to 1:4. The anolyte gas pump and the water sample gas pump both pump air or nitrogen into the anolyte and the water sample to be tested at the same flow rate. The anolyte composition is: CH3COONa: 1.0 g / L; (NH4)2SO4: 0.386 g / L; K2SO4: 0.149 g / L; Na2HPO4·12H2O: 10.25 g / L; NaH2PO4·2H2O: 3.31 g / L; yeast extract powder: 0.05 g / L.

[0013] Furthermore, the cathode sample introduction system in S1 includes catholyte, a catholyte inlet pump, and a catholyte air pump. The catholyte inlet pump pumps the catholyte into the cathode chamber at a flow rate of 0.1-100 mL / min through the cathode inlet. The catholyte air pump pumps air into the catholyte at a constant flow rate. The catholyte composition is: Na₂HPO₄·12H₂O: 6.91 g / L; NaH₂PO₄·2H₂O: 4.79 g / L.

[0014] Furthermore, the current loop in S1 includes a wire and a resistor, and the data acquisition system includes a reference electrode, a data card, and a computer. The wire connects the anode electrode, the resistor, and the cathode electrode in series to form a current loop. The wire is made of copper, aluminum, or titanium. The reference electrode is placed near the anode electrode to monitor the anode potential. The reference electrode is an Ag / AgCl electrode or a saturated calomel electrode. The data acquisition card is connected to the reference electrode, the resistor, and the computer to collect the voltage across the reference electrode and the resistor and store it in the computer.

[0015] The specific process for acclimating the oxygen-resistant anode MFC sensor is as follows: In step S1, sludge from the oxidation ditch of a wastewater treatment plant is inoculated into the anolyte as a source of bacteria for the oxygen-resistant anode biofilm. Simultaneously, deionized water is used as the test sample. Air is pumped into the anolyte, test sample, and cathode liquid at a flow rate of 10-800 mL / min. The flow rates of the anolyte inlet pump, test sample inlet pump, and cathode liquid inlet pump are set to 0.02-20 mL / min, 0.08-80 mL / min, and 0.1-100 mL / min, respectively. The resistance is set to 10-100000 Ω. The oxygen-resistant anode MFC sensor is acclimated and operated at room temperature (24℃-28℃). Bacterial inoculation is only performed on the first day of acclimation; from the second day onwards, no further bacterial inoculation is done. When the change in the output voltage across the resistor is less than 5% over 24 hours, it indicates that the oxygen-resistant anode biofilm acclimation and startup of the MFC sensor is successful.

[0016] The specific process for detecting the biotoxicity of water or environmental samples using an oxygen-resistant anode MFC sensor is as follows: In step S2, the deionized water in the test sample is replaced with a water sample containing toxic pollutants. The sample is run continuously for 10-600 minutes. The electrostatic inhibition rate is calculated based on the change in the output voltage across the resistor before and after the oxygen-resistant anode is injected with the pollutant. The formula for calculating the electrostatic inhibition rate is as follows:

[0017]

[0018] In the formula, U nor U represents the average output voltage of the sensor during stable operation before the addition of toxic pollutants. tox The average output voltage of the sensor during a period of time before the toxic pollutant is removed after a specified time has elapsed since the pollutant was added.

[0019] The beneficial effects of this technical solution are:

[0020] (1) Significantly improves the oxygen tolerance of the sensor: This invention constructs a double-layer biofilm structure at the anode, consisting of an outer layer of aerobic bacteria and an inner layer of anaerobic electroactive bacteria, through a specific aerobic acclimation strategy. The outer layer of aerobic bacteria effectively consumes dissolved oxygen in the sample, creating a relatively stable anaerobic environment for the inner layer of anaerobic electrogenic bacteria. This overcomes the problem of signal baseline drift or even failure of traditional MFC sensors in oxygenated water bodies, significantly enhancing the sensor's operational stability and applicability under different dissolved oxygen concentrations. It is particularly suitable for monitoring real-world environmental samples such as open water bodies or aerated wastewater.

[0021] (2) Significantly Improved Sensitivity of Biotoxicity Detection: This invention utilizes a unique double-layer biofilm structure and a synergistic inhibition mechanism to improve detection sensitivity. When toxic substances are present, they not only directly inhibit the activity of anaerobic electroactive microorganisms in the inner layer but also suppress the oxygen consumption capacity of aerobic bacteria in the outer layer, leading to greater oxygen permeation into the inner layer. The synergistic inhibitory effect of oxygen and toxic substances on the anaerobic electroactive bacteria in the inner layer results in a much greater decrease in the electrogenic signal than the simple toxic substance inhibition effect in traditional sensors. This allows for more sensitive detection of low concentrations of biotoxic substances, meeting the needs of early warning.

[0022] (3) Achieving synergistic improvement of oxygen tolerance and high sensitivity: Unlike traditional methods that only focus on improving oxygen tolerance or only optimize under anaerobic conditions, this invention successfully combines the improvement of oxygen tolerance with the enhancement of toxicity response sensitivity through an innovative aerobic acclimatization regulation strategy, solving the technical bottleneck of existing technologies that cannot take both into account. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection of the present invention;

[0024] Figure 2 The output voltage changes during the acclimatization process of the oxygen-tolerant anode MFC sensor in the example and the anaerobic anode MFC sensor in the control example are shown.

[0025] Figure 3 As an example, the oxygen-resistant anode MFC sensor detects the change in output voltage during the detection of different concentrations of Cu(II);

[0026] Figure 4 As a control example, the anaerobic anode MFC sensor was used to detect the change in output voltage during the detection of different concentrations of Cu(II).

[0027] Figure 5 As an example, the oxygen-resistant anode MFC sensor detects the change in output voltage at different oxygen concentrations of 5 mg / L Cu(II);

[0028] In the diagram: 1. Anode electrode; 2. Anode chamber; 3. Anode inlet; 4. Anode liquid inlet pump; 5. Anode liquid; 6. Anode liquid air pump; 7. Water sample to be tested; 8. Water sample air pump to be tested; 9. Water sample inlet pump to be tested; 10. Reference electrode; 11. Anode outlet; 12. Resistor; 13. Wire; 14. Cathode outlet; 15. Data acquisition card; 16. Computer; 17. Cathode liquid air pump; 18. Cathode liquid; 19. Cathode liquid inlet pump; 20. Cathode inlet; 21. Cathode chamber; 22. Cathode electrode; 23. Diaphragm. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0030] Example:

[0031] like Figure 1 The diagram shows a schematic of the oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection according to the present invention. The following is the construction process of the sensor of the present invention:

[0032] Step 1: Construct the MFC sensor. Both the anode chamber 2 and the cathode chamber 21 are made of plexiglass. The two reaction chambers are identical in size, with an external cubic structure and an internal cylindrical cavity. Each chamber has a volume of 28 mL and is separated by a cation exchange membrane (CMI-7000) diaphragm 23.

[0033] Step 2: Set up the electrodes and current loop. Place the anode electrode 1 (carbon felt and carbon rod) and the reference electrode 10 (saturated calomel electrode) in the anode chamber 2, and simultaneously place the cathode electrode 22 (carbon felt and carbon rod) in the cathode chamber 21. The carbon rod has the following dimensions: The carbon felt measures 2.0cm × 2.0cm × 1.0cm. The anode electrode 1, resistor 12, and cathode electrode 22 are connected in series to form a current loop using wire 13 (copper wire), and resistor 12 is set to 1000Ω.

[0034] Step 3: Set up the anode and cathode sample introduction systems. The anode inlet 3 and anode outlet 11 in the anode chamber, and the cathode inlet 20 and cathode outlet 14 in the cathode chamber, are all 2mm inner diameter straight-through quick-connect air hoses. The anolyte inlet pump 4, the sample inlet pump 9, and the cathode inlet pump 19 are all peristaltic pumps. The anolyte air pump 6, the sample inlet pump 8, and the cathode air pump 17 are all Haili silent adjustable air pumps.

[0035] Step 4: Set up the data acquisition system. Connect the 32-channel single-ended analog input data acquisition card 15 to the reference electrode 22, the two ends of the resistor 12, and the computer 16 respectively. Set the data acquisition time interval to 1 minute.

[0036] Step 5: Activate the MFC sensor. Place 2L of anolyte 5, water sample 7, and catholyte 18 into separate borosilicate reagent bottles. Anolyte 5 has the following composition: CH3COONa: 1.0 g / L; (NH4)2SO4: 0.386 g / L; K2SO4: 0.149 g / L; Na2HPO4·12H2O: 10.25 g / L; NaH2PO4·2H2O: 3.31 g / L; yeast extract powder: 0.05 g / L. Water sample 7 is deionized water. Catholyte 18 has the following composition: Na2HPO4·12H2O: 6.91 g / L; NaH2PO4·2H2O: 4.79 g / L. Meanwhile, the flow rates of the anolyte inlet pump 4, the water sample inlet pump 9, and the catholyte inlet pump 19 were set to 0.1 mL / min, 0.4 mL / min, and 0.5 mL / min, respectively.

[0037] Step Six: Acclimation of the Oxygen-Tolerant Anode MFC Sensor. Set the air flow rate of the anolyte air pump 6, the water sample air pump 8, and the cathode air pump 17 to 100 mL / min (corresponding dissolved oxygen concentrations of 8.0 ± 0.3 mg / L in the anolyte 5, water sample 7, and cathode 18). Acclimate and operate the MFC sensor at room temperature (24℃-28℃). On the first day of acclimation, add 100g of sludge from a wastewater treatment plant's oxidation ditch to the anolyte as an inoculum. From the second day onwards, replace the anolyte with one free of inoculum and continue acclimation. When the change in output voltage across resistor 12 is less than 5% over 24 hours, it indicates that the oxygen-tolerant anode biofilm acclimation and startup of the MFC sensor is successful.

[0038] Step 7: Detection of biotoxicity using an oxygen-resistant anode MFC sensor. Taking Cu(II) as an example of a toxic pollutant, after replacing the deionized water in water sample 7 with a Cu(II)-containing solution, the oxygen-resistant anode MFC sensor was run continuously for 400 minutes. The biotoxicity of Cu(II) was calculated based on the output voltage data across resistor 12 stored in the data acquisition system. Following the above procedure, Cu(II) concentrations of 0.375 mg / L, 0.625 mg / L, 1.25 mg / L, 6.25 mg / L, 8.75 mg / L, and 12.5 mg / L were detected. Since the flow rate ratio of the anolyte to the water sample was 1:4, the actual detected Cu(II) concentrations were 0.3 mg / L, 0.5 mg / L, 1.0 mg / L, 5.0 mg / L, 7.0 mg / L, and 10.0 mg / L, respectively.

[0039] Step 8: Detecting biotoxicity using an oxygen-resistant anode MFC sensor under different dissolved oxygen conditions. Taking Cu(II) as an example of a toxic pollutant, the flow rates of air pumped by the anolyte gas pump 6 and the water sample gas pump 8 were simultaneously set to 0 mL / min, 100 mL / min, or 300 mL / min, so that the oxygen-resistant anode MFC sensor could operate at dissolved oxygen concentrations of 0.1 ± 0.1 mg / L, 8.0 ± 0.3 mg / L, and 16.0 ± 0.5 mg / L, respectively. Then, following Step 7, the biotoxicity of 6.25 mg / L Cu(II) under different dissolved oxygen conditions was detected.

[0040] Step 9: Calculate the power generation inhibition rate. The power generation inhibition rate reflects the biotoxicity of toxic pollutants, and the calculation formula is as follows:

[0041]

[0042] In the formula, U nor The average output voltage of the oxygen-resistant anode MFC sensor during 20 minutes of stable operation before the addition of toxic pollutants; U tox The average output voltage of the oxygen-resistant anode MFC sensor during the 20-minute period (380-400 minutes) before the toxic pollutant was added.

[0043] Example for comparison:

[0044] This comparative example demonstrates the detection of different concentrations of Cu(II) using a conventional anaerobic MFC sensor. During the acclimation of the conventional anaerobic MFC sensor, the air flow rates of both the anolyte gas pump 6 and the sample gas pump 8 in step six of Example 1 were set to 0 mL / min. When using the conventional anaerobic MFC sensor to detect different concentrations of Cu(II), the Cu(II) concentrations in step seven of Example 1 were set to 1.25 mg / L, 6.25 mg / L, 12.5 mg / L, 25.0 mg / L, 37.5 mg / L, and 62.5 mg / L. Since the flow rate ratio of the anolyte to the sample liquid was 1:4, the actual detected Cu(II) concentrations were 1.0 mg / L, 5.0 mg / L, 10.0 mg / L, 20.0 mg / L, 30.0 mg / L, and 50.0 mg / L. All other operating conditions remained consistent with Example 1.

[0045] Results and Analysis

[0046] During the startup phase, the output voltage changes of the oxygen-resistant anode MFC sensor and the anaerobic anode MFC sensor are as follows: Figure 2 As shown in the figure, after approximately 180 hours of acclimatization, the output voltage of the oxygen-tolerant anode MFC sensor stabilized at 0.259 ± 0.001 V, with a maximum voltage fluctuation rate of less than 0.23% over 24 hours. Meanwhile, after approximately 130 hours of acclimatization, the output voltage of the anaerobic anode MFC sensor stabilized at 0.493 ± 0.004 V, corresponding to a maximum voltage fluctuation rate of 0.89% over 24 hours. These results indicate that both the oxygen-tolerant and anaerobic anode MFC sensors have successfully completed their acclimatization and startup, achieving a stable electrical signal output state.

[0047] During operation, the output voltage changes of the oxygen-resistant anode MFC sensor and the anaerobic anode MFC sensor when detecting different concentrations of Cu(II) are as follows: Figure 3 and Figure 4 As shown. When detecting 0.3 mg / L–10.0 mg / L Cu(II), the electrostatic generation of the oxygen-resistant anode MFC sensor was suppressed, with the calculated suppression rate ranging from 5.1 ± 1.7% to 61.5 ± 3.2%. Figure 3 In contrast, the anaerobic anodic MFC sensor exhibited a response in the concentration range of 1.0 mg / L–50.0 mg / L Cu(II), with an electrogenic inhibition rate of 4.2 ± 1.5%–39.2 ± 2.4%. Figure 4 Taking 5.0 mg / L Cu(II) as an example for comparison, the electrogenic inhibition rate of the oxygen-resistant anode MFC sensor reached 27.7 ± 2.5%, which is much higher than that of the anaerobic anode MFC sensor (5.9 ± 1.6%), indicating that the oxygen-resistant anode MFC sensor has higher sensitivity.

[0048] The output voltage variation of the oxygen-resistant anode MFC sensor when detecting 5 mg / L Cu(II) at different oxygen concentrations is as follows: Figure 5 As shown, within the dissolved oxygen concentration range of 0.1 mg / L–16.0 mg / L, the electrogenic inhibition rate of the oxygen-resistant anode MFC sensor for detecting 5 mg / L Cu(II) remained stable at 27.7 ± 2.5%–29.0 ± 3.1%. Statistical analysis showed no significant difference in electrogenic inhibition rates among different dissolved oxygen concentrations (P = 0.31, P > 0.05), indicating that the oxygen-resistant anode MFC sensor has excellent resistance to dissolved oxygen interference.

[0049] In summary, when detecting biotoxicity, the oxygen-resistant anode MFC sensor of this invention has higher sensitivity and resistance to oxygen interference than the traditional anaerobic anode MFC sensor.

[0050] The above descriptions are merely embodiments of the present invention, and common technical solutions or characteristics known in the schemes are not described in detail here. For those skilled in the art, various modifications and improvements can be made without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A highly sensitive oxygen-resistant anode MFC sensor for biotoxicity detection, characterized in that: The device includes an anode chamber, an anode sample introduction system, a diaphragm, a cathode chamber, a cathode sample introduction system, a current loop, and a data acquisition system. The diaphragm is disposed between the anode chamber and the cathode chamber. An anode electrode is disposed in the anode chamber, and a cathode electrode is disposed in the cathode chamber. The anode electrode and the cathode electrode are connected in series by a wire to form a current loop. The anode sample introduction system is used to deliver anolyte and the water sample to be tested into the anode chamber. The cathode sample introduction system is used to deliver catholyte into the cathode chamber. The data acquisition system is used to acquire electrical signals. The anode electrode has a double-layer biofilm formed through aerobic acclimation for biotoxicity detection. The double-layer biofilm includes an outer aerobic bacterial layer that consumes dissolved oxygen and an inner anaerobic electroactive bacterial layer that generates electricity.

2. The oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection according to claim 1, characterized in that: The diaphragm is a cation exchange membrane, an anion exchange membrane, or a bipolar membrane.

3. The oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection according to claim 1, characterized in that: The anode electrode is a carbon felt, carbon brush, carbon granules, or carbon cloth; the cathode electrode is a stainless steel mesh, platinum electrode, carbon felt, carbon brush, or carbon cloth.

4. The oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection according to claim 1, characterized in that, The composition of the anolyte is: CH3COONa: 1.0 g / L; (NH4)2SO4: 0.386 g / L; K2SO4: 0.149 g / L; Na2HPO4·12H2O: 10.25 g / L; NaH2PO4·2H2O: 3.31 g / L; yeast extract powder: 0.05 g / L; The composition of the catholyte is: Na2HPO4·12H2O: 6.91 g / L; NaH2PO4·2H2O: 4.79 g / L.

5. The oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection according to claim 1, characterized in that: The current loop includes a wire and a resistor. The data acquisition system includes a reference electrode, a data card, and a computer. The wire connects the anode electrode, the resistor, and the cathode electrode in series to form a current loop. The wire is made of copper, aluminum, or titanium. The reference electrode is located near the anode electrode and is used to monitor the anode potential. The reference electrode is an Ag / AgCl electrode or a saturated calomel electrode. The data acquisition card is connected to the reference electrode, the resistor, and the computer to collect the voltage across the reference electrode and the resistor and store it in the computer.

6. The method for acclimatization and preparation of a high-sensitivity oxygen-resistant anodic MFC sensor for biotoxicity detection according to any one of claims 1-5, characterized in that, The following steps are involved: S1. Construct a biotoxicity sensor for a microbial fuel cell. The sensor includes an anode chamber, an anode sample introduction system, a diaphragm, a cathode chamber, a cathode sample introduction system, a current loop, and a data acquisition system. S2. Inoculate the anode chamber with a bacterial source containing aerobic and anaerobic electroactive bacteria, and provide anolyte; S3. The anode electrode is acclimatized under aerobic conditions by continuously supplying oxygen to the anode chamber environment until a double-layer biofilm is formed on the anode electrode, consisting of an outer layer of aerobic bacteria and an inner layer of anaerobic electroactive bacteria, and a stable electrical signal output is obtained.

7. The method for acclimatization and preparation of a high-sensitivity oxygen-resistant anodic MFC sensor for biotoxicity detection according to claim 6, characterized in that: In step S2, the bacterial source is sludge from the oxidation ditch in the wastewater treatment plant using the oxidation ditch process.

8. The method for acclimatization and preparation of a high-sensitivity oxygen-resistant anodic MFC sensor for biotoxicity detection according to claim 6, characterized in that: In step S3, the continuous supply of oxygen is achieved by pumping air into the anolyte and / or the water sample to be tested introduced into the anode chamber.

9. The method for acclimatization and preparation of a high-sensitivity oxygen-resistant anodic MFC sensor for biotoxicity detection according to claim 6, characterized in that: In step S3, the completion of acclimatization is determined by monitoring the output voltage across the resistor connecting the anode and cathode electrodes. When the change in output voltage is less than 5% within 24 hours, acclimatization is considered complete.

10. A method for detecting biotoxicity using an oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection according to any one of claims 1-5, characterized in that, The following steps are involved: S1. Introduce the water body or environmental sample to be tested into the anode chamber of the sensor; S2. Monitor the electrical signal output of the sensor; S3. The biotoxicity of the water or environmental sample is characterized by the degree of inhibition of the electrical signal output after it is introduced into the water or environmental sample.

11. A method for detecting biotoxicity using an oxygen-resistant anode MFC sensor for high-sensitivity biotoxicity detection according to claim 10, characterized in that, In step S1, the water body or sample to be tested is continuously pumped into the anode chamber at a constant flow rate; in step S3, the degree of inhibition is obtained by calculating the power generation inhibition rate, which is calculated based on the sensor output voltage before and after the introduction of the water body or environmental sample to be tested.

12. The method for detecting biotoxicity using a high-sensitivity oxygen-resistant anode MFC sensor according to claim 11, characterized in that, The power generation suppression rate is calculated according to the following formula: In the formula, U nor U represents the average output voltage of the sensor during stable operation before the addition of toxic pollutants. tox The average output voltage of the sensor during a period of time before the toxic pollutant is removed after a specified time has elapsed since the pollutant was added.

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