A microbial fuel cell-based water treatment oxidant concentration detection system and detection method

Abstract

The application provides a water treatment oxidant concentration detection system based on a microbial fuel cell, which comprises a microbial fuel cell and an electric signal processing device, and detects the oxidant concentration in a water sample to be measured by a cathode chamber, wherein the cathode chamber is open to air; an anode chamber maintains an anaerobic state; the electric signal processing device comprises a voltage signal acquisition device and a quantitative analysis module based on a pre-calibrated current-concentration relationship, is used for acquiring and processing voltage and current information, and calculates the oxidant concentration in the water sample to be measured. The application utilizes the principle that the reduction reaction of oxidants in the cathode causes the change of the output voltage of the system, acquires the voltage signal in real time, substitutes the voltage signal into a pre-calibrated linear equation to calculate the oxidant concentration, and realizes the high-sensitivity, real-time and rapid detection of the novel water treatment oxidant. The system has the advantages of strong anti-interference, low cost, simple maintenance and the like, and is suitable for the oxidant concentration monitoring in the scenes of industrial wastewater treatment and drinking water treatment.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and more specifically, to a water treatment oxidant concentration detection system and method based on a microbial fuel cell. Background Technology

[0002] In recent years, biosensors based on microbial fuel cells (MFCs) have gradually become a research hotspot due to their simple structure and high sustainability. In this system, microorganisms in the anode chamber act as biorecognition elements, while proton exchange membranes and electrodes serve as the core components of the sensor. Bacteria can sense changes in the concentration of the target analyte and respond rapidly through output current. Currently, there are two strategies for detecting concentration using biosensors based on microbial fuel cells: anode detection and cathode detection. Anode detection utilizes the reduction in output current caused by the inhibition of microbial respiration by the analyte. For cathode detection, similar to anodes, electroactive biofilms can also be developed on cathodes, utilizing the reversible metabolism of certain microorganisms to absorb electrons from the cathode for respiration. These microorganisms are highly sensitive to pollutants such as ions. Biocathodes also have a significant advantage: these "electroautotrophic" microorganisms do not need to be constrained by organic matter like anode microorganisms, so they can detect water bodies saturated with dissolved oxygen but lacking organic matter. On the other hand, although biocathode sensing elements have certain advantages over anode-based sensors, they are still susceptible to high toxicity shocks, which may cause some irreversible changes to the microbial framework. Non-biocathode sensing elements may be an alternative to avoid dependence on biocatalysts. For example, some metals, such as Cr, Ag, Fe, and Mn, have high reduction potentials, allowing them to directly accept electrons from the cathode for charge neutralization. This generates a variable current response signal based on the concentration of the analyte, which can be calibrated to develop biosensors based on non-biological cathodes.

[0003] With the acceleration of urbanization and industrialization, water pollution has become increasingly severe. Traditional oxidants (such as chlorine and ozone) face bottlenecks in treating recalcitrant organic matter, drug-resistant pathogens, and emerging pollutants (such as drug residues and microplastics), including insufficient efficiency, high toxicity of byproducts, and secondary pollution. Against this backdrop, novel water treatment oxidants have emerged, which enhance the generation of free radicals (such as hydroxyl radicals (·OH) and sulfate radicals (SO4·)). -Optimizing reaction pathways and employing green catalysis technologies have significantly improved oxidation efficiency and environmental compatibility, providing an important research direction for achieving efficient, low-consumption, and sustainable development in the water treatment field. For novel water treatment oxidants such as peracetic acid (PAA), periodate (PI), persulfate (PMS), and persulfate (PDS), commonly used concentration detection methods include spectrophotometry, chromatography, and electrochemical methods. Spectrophotometry is low-cost, simple to operate, and portable, but it is susceptible to interference from other components, has low sensitivity, and is cumbersome. Chromatography can perform multi-component analysis with high selectivity, making it suitable for detecting complex water samples and trace analysis; however, the instruments are expensive, maintenance is complex, and detection is time-consuming. Electrochemical methods offer rapid response and portable design, but suffer from poor stability and require frequent calibration, making them suitable for real-time, efficient, and rapid concentration level detection.

[0004] In view of this, the applicant hereby submits this application after studying the existing technology. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a water treatment oxidant concentration detection system based on a microbial fuel cell, comprising a microbial fuel cell and an electrical signal processing device. The microbial fuel cell has an anode chamber and a cathode chamber, which are separated by a proton exchange membrane.

[0006] The concentration of oxidant in the water sample to be tested is detected using the cathode chamber. Sodium sulfate with a concentration of 50 mM is added to the cathode chamber as a supporting electrolyte and it is open to the air. A cathode made of platinum-plated titanium electrode or carbon fiber brush is installed in the cathode chamber. The anode chamber is kept in an anaerobic state; the anode chamber is equipped with an anode made of carbon fiber brushes; The electrical signal processing device includes a voltage signal acquisition device and a quantitative analysis module based on a pre-calibrated current-concentration relationship. The voltage signal acquisition device is connected to the anode and cathode of the microbial fuel cell and is used to acquire the voltage and current between the anode and cathode. The quantitative analysis module is used to receive the voltage and current information acquired by the voltage signal acquisition device and process and calculate it to obtain the oxidant concentration in the water sample to be tested.

[0007] The anode chamber and cathode chamber have volumes of 200 mL and 100 mL, respectively, with a volume ratio of 2:1.

[0008] The oxidizing agents tested were oxyacetic acid (PAA), periodate (PI), persulfate (PMS), or persulfate (PDS).

[0009] The voltage signal acquisition device acquires the voltage and current signals between the anode and cathode in real time, and the quantitative analysis module calculates the corresponding oxidant concentration through a pre-calibrated linear equation.

[0010] The testing steps are as follows: S1: Add 50mM sodium sulfate to the cathode chamber as a supporting electrolyte; S2: Inject the water sample to be tested into the cathode chamber; S3: Start the system and collect voltage signals in real time; S4: Calculate the oxidant concentration using a pre-calibrated linear equation.

[0011] By adopting the above technical solution, the present invention can achieve the following technical effects: 1. High sensitivity and accuracy: This invention employs a non-biological cathode design, avoiding the influence of microbial toxicity. Sodium sulfate enhances conductivity, and the voltage response exhibits a significant linear relationship with the oxidant concentration (R²>0.9). The PAA detection sensitivity reaches as high as 0.01 mM, far exceeding that of traditional spectrophotometry. 2. Real-time and rapid response: Data can be acquired in real time with a short response time, making it suitable for monitoring dynamic water treatment processes. It has significant advantages over liquid chromatography (4 minutes) for detecting PI. 3. Strong anti-interference ability: Non-biological cathodes avoid the influence of microbial toxicity and are suitable for highly toxic wastewater environments, overcoming the shortcomings of traditional biological cathode sensors and biological anode sensors that are susceptible to shock loads; 4. Low cost and easy maintenance: No expensive reagents or complex instruments are required, maintenance is simple, the system operates stably, and the long-term cost is far lower than that of chromatography and traditional electrochemical methods. 5. Multifunctionality: It can detect a variety of novel water treatment oxidants (PAA, PI, PMS, PDS), has a wide range of applications, and fills the gap in existing technologies for rapid detection methods for these novel oxidants. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the concentration detection system; Figure 2 The current response versus time curve after adding 0.1 mM PAA; Figure 3 Linear curves of current response to the addition of 0.1 mM PAA concentration; Figure 4The linear fitting relationship between the output current rise and PAA concentration when an external 1000Ω resistor is connected to the reactor is shown. Figure 5 The linear fit relationship between the output current rise and PAA concentration when an external 10Ω resistor is connected to the reactor; Figure 6 The response curve of the added 1mM PI current as a function of time; Figure 7 Linear curves of current response to the addition of 1 mM PI concentration; Figure 8 The linear fitting relationship between the output current rise and PI concentration when an external 1000Ω resistor is connected to the reactor is shown. Figure 9 The curve showing the response of the added 0.5mM PMS current over time; Figure 10 Linear curves of current response to the addition of 0.5 mM PMS; Figure 11 The linear fitting relationship between the output current rise and PMS concentration when an external 1000Ω resistor is connected to the reactor is shown. Figure 12 The linear fitting relationship between the output current rise and PMS concentration when an external 10Ω resistor is connected to the reactor is shown. Figure 13 The current response curve over time after adding 1mM PDS; Figure 14 Linear curves of current response to the addition of 1 mM PDS concentration; Figure 15 The linear fit relationship between the output current rise and PDS concentration when an external 1000Ω resistor is connected to the reactor is shown. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0015] The specific detection principle of this invention is as follows: (1) Electroactive bacteria at the MFC anode provide electron acceptors, which are transferred to the cathode through the external circuit, activating the OO bonds in the oxidant. The oxidant accepts electron acceptors at the cathode, enhancing the current flow and thus creating a momentary voltage surge. Afterward, the voltage gradually decreases, indicating that the oxidant is gradually consumed. Peracetic acid (PAA) undergoes the following reaction in this process: CH3C(O)OOH+e - →CH3C(O)O - +•OH(1) CH3C(O)OOH+e - →CH3C(O)O•+OH - (2) CH3C(O)OOH+•OH→CH3CO•+H2O+O2(3) CH3C(O)OOH+•OH→CH3C(O)OO•+H2O(4) CH3C(O)OOH+•OH→CH3C(O)OH+HO2•(5) CH3C(O)OOH+CH3C(O)O•→CH3C(O)OO•+CH3C(O)OH(6) CH3C(O)O•→CH3•+CO2(7) CH3•+O2→CH3(O)O•(8) CH3C(O)OO•+CH3C(O)OO•→2CH3C(O)O•+O2(9) Periodate (PI) undergoes the following reaction during this process: IO4 - +2H + +2e - →IO3 +H2O(10) IO3 +6H + +6e - →I - +3H2O(11) I2+I - →I 3- (12) During this process, persulfate (PMS) also undergoes the following reaction: The core activation step generates SO4• - HSO5 - +H - +e - →SO4• - +H2O(13) Direct reduction pathway: HSO5- +e - →SO4 2 +•OH(14) SO4• - Subsequent reaction: SO4• - +H₂O→SO₄ 2 +•OH+H - (15) SO4• +e →SO4 2 (16) SO4• +H - +2e →HSO4 (17) •OH- consumption reaction: 2•OH + 2H+ - +2e - →2H2O(18) Persulfate (PDS) undergoes the following reaction during this process: The core activation step generates SO4• - S2O8² - +e - →SO4• - +SO4² - (19) Direct reduction pathway: S2O8² - +2e - →2SO4² - (20) SO4• - +H + +e - →HSO4 - (twenty one) SO4• - Subsequent reaction: SO4• - +H₂O→SO₄² - +•OH+H + (twenty two) SO4• - +e - →SO4² - (twenty three) SO4• - +H + +e - →HSO4 - (twenty four) • OH consumption reaction: • OH + H+ + +e- →H2O(25) (2) Sodium sulfate provides stable ionic strength and enhances electron transfer efficiency.

[0016] (3) The concentration of oxidant is positively correlated with the cathode reaction rate. When the concentration decreases, the number of electron acceptors decreases, resulting in a decrease in the system output current. The concentration can be quantitatively analyzed by means of the calibration curve.

[0017] like Figure 1 As shown, this invention provides a water treatment oxidant concentration detection system based on a microbial fuel cell, comprising a microbial fuel cell and an electrical signal processing device. The microbial fuel cell is a rectangular dual-chamber microbial fuel cell, with actual volumes of 200 mL for the anode chamber and 100 mL for the cathode chamber, which are separated by a proton exchange membrane (PEM). A carbon fiber brush is used as the anode electrode in the anode chamber, and a platinum-plated titanium electrode or a carbon fiber brush is used as the cathode electrode in the cathode chamber. This application preferably uses a platinum-plated titanium electrode, as this effectively increases catalytic activity.

[0018] 200 mL of wastewater (taken from the University Town Wastewater Treatment Plant in Minhou County, Fuzhou City) was added to the anode chamber as the anolyte. 0.062 g of NH4Cl, 0.538 g of NaH2PO4•H2O, 0.866 g of Na2HPO4, 0.026 g of KCl, 2.5 mL of vitamin solution, and 2.5 mL of trace element solution were added to the anolyte. The anode chamber was kept in an anaerobic state. The compositions of the vitamin solution and trace element solution are shown in Tables 1 and 2, respectively.

[0019] Table 1 Preparation of Vitamin Solution

[0020] Table 2 Preparation of Trace Element Metal Solutions

[0021] Sodium sulfate with a concentration of 50 mM was added to the cathode chamber as a supporting electrolyte and then released into the air. The electrical signal processing device includes a voltage signal acquisition device and a quantitative analysis module based on a pre-calibrated current-concentration relationship. The voltage signal acquisition device has a resistor and a collector. The resistor is connected to the anode and cathode of the microbial fuel cell through a copper wire. The collector collects the voltage and current between the two. The quantitative analysis module receives the voltage and current information collected by the voltage signal acquisition device, processes and calculates it, and calculates the oxidant concentration in the water sample to be tested according to the pre-calibrated linear equation.

[0022] Example 1 The steps for detecting peracetic acid (PAA) are as follows: S1: The concentrations of PAA and coexisting H2O2 in the PAA stock solution were determined using the KI-DPD method, and the concentration of H2O2 was determined using the potassium titanium oxalate method to obtain the concentration ratio of PAA and coexisting H2O2. The stock solution was prepared into solutions with concentrations of 0.1 mM, 0.08 mM, 0.06 mM, 0.04 mM and 0.02 mM, respectively. The absorbance of each concentration solution was determined using the KI-DPD method, and a standard curve of PAA concentration was plotted based on the concentration ratio of PAA and coexisting H2O2. S2: Inject 99 mL of 50 mM sodium sulfate electrolyte into the cathode chamber, add 0.1 mL of 0.1 mol / L peracetic acid standard solution to obtain 0.1 mM peracetic acid catholyte, and connect the anode and cathode with wires and a 1000 Ω resistor; S3: Start the system and record the instantaneous voltage value (example data: 0.1mM→0.970V); S4: Record voltage values ​​at 10, 20, 30, 45, 60, 80, 100, and 120 minutes, and sample to detect PAA concentration; calculate the current value according to I=U / R, and the current response changes with time as follows: Figure 2 As shown; where I is current, U is voltage, and R is resistance; S5: Determine the relationship curves between current response and PAA concentration at each time point to determine the sensing performance of the reactor. For example... Figure 3 As shown, the linear equations for PAA and current can be derived: C = 1463.867I - 1319.389 R 2 = 0.9804, Where C represents the oxidant concentration, I is the current, and R... 2 Indicates the coefficient of determination; S6: Replace the catholyte with a 50mM sodium sulfate solution. Connect the anode and cathode using a wire and a 1000Ω resistor, and record the initial current value. Then add a certain concentration of PAA solution and record the instantaneous current rise. Repeat this step multiple times, with PAA concentrations of 0.1mM, 0.08mM, 0.06mM, 0.04mM, and 0.02mM, respectively. Record the corresponding current rise values ​​and plot a linear fitting curve between the current rise value of the microbial fuel cell and the initial PAA concentration of the catholyte. Figure 4 As shown, the linear equation can be obtained: ΔI = 0.81C + 0.005, R² = 0.9944; Where ΔI is the current rise value; S7: Replace the catholyte with a 50mM sodium sulfate solution containing PAA. Connect the anode and cathode using a wire and a 10Ω resistor, and record the initial current value. Then add a certain concentration of concentrated PAA solution and record the instantaneous current rise. Repeat this step multiple times, with PAA concentrations of 0.1mM, 0.2mM, 0.4mM, 0.6mM, 0.8mM, and 1mM, respectively, and record the corresponding current rise values. Plot a linear fitting curve between the current rise value of the microbial fuel and the initial PAA concentration of the catholyte, as shown below. Figure 5 As shown, the linear equation can be obtained: ΔI = 12.951C - 0.9581, R² = 0.9885.

[0023] In this system, the PAA provides electron acceptor in the cathode chamber, causing a momentary surge in the system current. The current surge is linearly related to the PAA concentration, and quantitative detection can be achieved through a calibration curve. Figure 4 and Figure 5 As shown, the PAA concentration and current response exhibit a good linear relationship, indicating that the system has high accuracy, high sensitivity and a wide detection range for PAA detection.

[0024] Example 2: The steps for periodate (PI) detection are as follows: S1: The concentration of sodium periodate was detected by liquid chromatography. Periodate solutions with concentrations of 1 mM, 0.8 mM, 0.6 mM, 0.4 mM and 0.2 mM were prepared, and a standard curve of sodium periodate concentration was plotted based on the peak area of ​​each concentration. S2: Inject 99 mL of 50 mM sodium sulfate electrolyte into the cathode chamber, add 1 mL of 0.1 mol / L sodium periodate standard solution to obtain a 1 mM periodate cathodic solution, and connect the anode and cathode with wires and a 1000 Ω resistor. S3: Start the system and record the instantaneous voltage value (example data: 1mM→1.467V). S4: Record voltage values ​​at 10, 20, 30, 45, 60, 80, 100, and 120 minutes, and sample to detect PI concentration; calculate the current value according to I=U / R, and the current response changes with time as follows: Figure 6 As shown; S5: Establish calibration curves for current response and PI concentration at various time points, such as... Figure 7 As shown, the sensing performance of the reactor was determined, and the linear equation was obtained: C = 1.9816I - 1.9157 R² = 0.9925; S6: Replace the catholyte with a 50mM sodium sulfate solution. Connect the anode and cathode using wires and a 1000Ω resistor, and record the initial current value. Then add a certain concentration of PI concentrate and record the instantaneous current rise. Repeat this step multiple times, with PI concentrations of 0.1mM, 0.08mM, 0.06mM, 0.04mM, and 0.02mM, respectively, and record the corresponding current rise values. Plot a linear fitting curve between the current rise value of the microbial fuel cell and the initial PI concentration of the catholyte, as shown below. Figure 8 As shown, the linear equation is obtained: ΔI = 0.5101C + 0.0459, R² = 0.9958.

[0025] In this system, the PI (pixel peroxide) provides the electron acceptor in the cathode chamber, causing a momentary surge in the system current. This current surge is linearly related to the PI concentration, and quantitative detection can be achieved through a calibration curve. Figure 8 As shown, the PI concentration and current response exhibit a good linear relationship, indicating that the system has high accuracy and high sensitivity for PI detection.

[0026] Example 3 The steps for detecting persulfate (PMS) are as follows: S1: The concentration of sodium persulfate was determined by KI spectrophotometry. Sodium persulfate concentrations of 1 mM, 0.8 mM, 0.6 mM, 0.4 mM and 0.2 mM were prepared, and a concentration standard curve of sodium persulfate was plotted based on the absorbance of each concentration. S2: Inject 99.5 mL of 50 mM sodium sulfate electrolyte into the cathode chamber, add 0.5 mL of 0.1 mol / L sodium persulfate standard solution to obtain 0.5 mM sodium persulfate catholyte, and connect the anode and cathode with wires and a 1000 Ω resistor. S3: Start the system and record the instantaneous voltage value (example data: 0.5mM→1.321V); S4: Record voltage values ​​at 10, 20, 30, 45, 60, 80, 100, and 120 minutes, and sample to detect PMS concentration; calculate the current value according to I=U / R, and the current response changes with time as follows: Figure 9 As shown; S5: Establish current response and PMS concentration calibration curves at various time points, such as Figure 10 As shown, the sensing performance of the reactor was determined, and the linear equation was obtained: C = 2.0019I - 1.7639 R²=0.9723; S6: Replace the catholyte with a 50mM sodium sulfate solution. Connect the anode and cathode using wires and a 1000Ω resistor, and record the initial current value. Then add a certain concentration of PMS concentrate and record the instantaneous current rise. Repeat this step multiple times, with PMS concentrations of 0.5mM, 0.4mM, 0.3mM, 0.2mM, and 0.1mM, recording the corresponding current rise values. Plot a linear fitting curve between the current rise value of the microbial fuel cell and the initial PI concentration of the catholyte, as shown below. Figure 11 As shown, the linear equation is obtained: ΔI = 0.89C - 0.009, R² = 0.9867; S7: Replace the catholyte with a 50mM sodium sulfate solution. Connect the anode and cathode using a wire and a 10Ω resistor, record the initial current value, and then add a certain concentration of PMS concentrate, recording the instantaneous current rise. Repeat this step multiple times, with PMS concentrations of 2mM, 1.5mM, 1mM, 0.7mM, and 0.5mM, recording the corresponding current rise values. Plot a linear fitting curve between the current rise value of the microbial fuel cell and the initial PMS concentration of the catholyte, as shown below. Figure 12 As shown, the linear equation is obtained: ΔI = 8.2114C - 4.403, R² = 0.9831.

[0027] In this system, PMS provides the electron acceptor in the cathode chamber, causing a momentary surge in the system current. The current surge is linearly related to the PMS concentration, and quantitative detection can be achieved through a calibration curve. Figure 11 and Figure 12 As shown, the PMS concentration and current response exhibit a good linear relationship, indicating that the system has high accuracy, high sensitivity and a wide detection range for PMS detection.

[0028] Example 4 Sodium persulfate (PDS) detection S1: The concentration of sodium persulfate (PDS) was determined by KI spectrophotometry. Standard solutions of sodium persulfate with concentrations of 1 mM, 0.8 mM, 0.6 mM, 0.4 mM and 0.2 mM were prepared, and a standard curve of PDS concentration was plotted based on the absorbance values ​​at each concentration. S2: Inject 99 mL of 50 mM sodium sulfate electrolyte into the cathode chamber, add 1 mL of 0.1 mol / L sodium persulfate (PDS) standard solution to obtain 1 mM sodium persulfate catholyte, and connect the anode and cathode using wires and a 1000 Ω resistor. S3: Start the system and record the instantaneous voltage value (example data: 1mM→1.03V); S4: Record voltage values ​​at 30, 60, 90, 120, 180, 240, 300, and 360 minutes, and sample to detect PDS concentration; calculate the current value according to I=U / R, and the current response changes with time as follows: Figure 13 As shown; S5: Establish calibration curves for current response and PDS concentration at various time points, such as... Figure 14 As shown, the sensing performance of the reactor was determined, and the linear equation was obtained: C = 4.8806I - 4.06896 R² = 0.9957; S6: Replace the catholyte with a 50 mM sodium sulfate solution. Connect the anode and cathode using a wire and a 1000Ω resistor, and record the initial current value. Then add a certain concentration of PDS concentrate and record the instantaneous current rise. Repeat this step multiple times, with the PDS concentration set successively to 0.1 mM, 0.08 mM, 0.06 mM, 0.04 mM, and 0.02 mM, recording the corresponding current rise values. Plot a linear fitting curve between the current rise value of the microbial fuel cell and the initial PDS concentration of the catholyte, as shown below. Figure 15 As shown, the linear equation is obtained: I= 0.031C-0.0038, R²=0.999.

[0029] In this system, PDS provides electron acceptors in the cathode chamber, causing a momentary surge in the system current. The current surge is linearly related to the PDS concentration, and quantitative detection can be achieved through a calibration curve. Figure 15 As shown, the PDS concentration and current response exhibit a good linear relationship, indicating that the system has high accuracy, high sensitivity and a wide detection range for PDS detection.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A water treatment oxidant concentration detection system based on a microbial fuel cell, comprising a microbial fuel cell and an electrical signal processing device, wherein the microbial fuel cell is separated into an anode chamber and a cathode chamber by a proton exchange membrane, characterized in that, The concentration of oxidant in the water sample to be tested is detected using the cathode chamber, which uses sodium sulfate as the supporting electrolyte and is open to the air. The anode chamber is kept in an anaerobic state; The electrical signal processing device includes a voltage signal acquisition device and a quantitative analysis module based on a pre-calibrated current-concentration relationship. The voltage signal acquisition device is connected to the anode and cathode of the microbial fuel cell and is used to acquire the voltage and current between the anode and cathode. The quantitative analysis module is used to receive the voltage and current information acquired by the voltage signal acquisition device and process and calculate it to obtain the oxidant concentration in the water sample to be tested.

2. The device according to claim 1, characterized in that... The volume ratio of the anode chamber to the cathode chamber is 2:

1.

3. The water treatment oxidant concentration detection system based on a microbial fuel cell according to claim 1, characterized in that... The anode chamber uses carbon fiber as the anode, and the cathode chamber uses platinum-plated titanium electrode or carbon fiber brush as the cathode.

4. The water treatment oxidant concentration detection system based on a microbial fuel cell according to claim 1, characterized in that... The concentration of sodium sulfate is 50 mM.

5. The water treatment oxidant concentration detection system based on a microbial fuel cell according to claim 1, characterized in that... The oxidant is peracetic acid, periodate, peroxymonosulfate, or persulfate.

6. The water treatment oxidant concentration detection system based on a microbial fuel cell according to claim 5, characterized in that... When the oxidant is peracetic acid, the oxidant concentration detection range is 0.01-20 mM; when the oxidant is periodate, the oxidant concentration detection range is 0.1-1 mM; when the oxidant is peroxymonosulfate, the oxidant concentration detection range is 0.1-100 mM; when the oxidant is persulfate, the oxidant concentration detection range is 0.1-1 mM.

7. A water treatment oxidant concentration detection system based on a microbial fuel cell according to claim 5, characterized in that... The voltage signal acquisition device acquires the voltage and current signals between the anode and cathode in real time, and the quantitative analysis module calculates the corresponding oxidant concentration through a pre-calibrated linear equation.

8. A water treatment oxidant concentration detection system based on a microbial fuel cell according to claim 7, characterized in that... , When the oxidant is peracetic acid, the linear equation is: C = 1463.867I - 1319.389 R²=0.9804； Where C represents the concentration of the oxidant, I is the current; R 2 Indicates the coefficient of determination; When the oxidant is periodate, the linear equation is: C = 1.9816I - 1.9157 R²=0.9925； When the oxidant is hydrogen persulfate, the linear equation is: C = 2.0019I - 1.7639 R²=0.9723; When the oxidant is persulfate, the linear equation is: C = 4.8806I - 4.06896 R²=0.9957。 9. A method for detecting the concentration of oxidant in water treatment, characterized in that... The concentration of oxidant in water treatment based on a microbial fuel cell, as described in any one of claims 1-8, is detected using the following steps: S1: Sodium sulfate is added to the cathode chamber as a supporting electrolyte; S2: Inject the water sample to be tested into the cathode chamber; S3: Start the system and collect voltage signals in real time; S4: Calculate the oxidant concentration using a pre-calibrated linear equation.

10. The method for detecting the concentration of a water treatment oxidant according to claim 9, characterized in that... In step S4, the pre-calibrated linear equation is obtained by preparing standard solutions of oxidant at different concentrations, measuring the system output current signal, establishing a current-concentration standard curve, and fitting the curve to obtain the linear equation.

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