A device for efficient pollutant removal using a dual-cathode photocatalytic microbial fuel cell

Abstract

This invention provides a device for efficient pollutant removal using a dual-cathode photocatalytic microbial fuel cell, belonging to the field of water pollution treatment and energy utilization technology. The device includes a reactor body, which is divided into a cathode chamber and an anode chamber by a proton exchange membrane. The cathode chamber is equipped with a PANI / CP / CuFe2O4 photocathode and an oxygen reduction air cathode. The illumination surface is made of quartz glass, and a light source is located on the outside. A circulation system runs through the cathode chamber. A carbon brush in the anode chamber is connected to the cathode via a wire and an external resistor to form a battery. Under illumination, the PANI / CP / CuFe2O4 photocathode and the H2O2 generated in situ by the air cathode undergo a heterogeneous photoelectric Fenton reaction, efficiently degrading pollutants while increasing power generation. The photocathode used in this invention solves the problems of high electron-hole recombination rates and difficulty in recovering powdered catalysts. This system uses dual cathodes, enabling continuous in-situ H2O2 generation, ensuring pollutant removal rates, and offering advantages such as simple control and high energy utilization.

Description

Technical Field

[0001] This invention belongs to the field of water pollution treatment and energy utilization technology, specifically relating to a dual-cathode microbial fuel cell device and the preparation of a CF / polyaniline / CuFe2O4 photocathode. It couples microorganisms and dual cathodes to synergistically degrade water pollutants and generate electricity. It adopts a circulation system for continuous removal of pollutants, which is an economical option that simultaneously achieves waste elimination and energy recovery. Background Technology

[0002] Currently, strengthening the control and efficient treatment of emerging water pollutants is of paramount importance. On the one hand, it is necessary to develop highly efficient catalytic materials to improve water purification efficiency; on the other hand, it is essential to strengthen research on coupling technologies to promote energy recovery and resource utilization.

[0003] Microbial fuel cells (MFCs) have emerged as a sustainable technology, utilizing microorganisms as catalysts to remove pollutants and generate electricity through the redox reactions of organic matter. However, existing MFCs suffer from high costs and relatively low overall performance. To address these shortcomings, illumination has been introduced to enhance MFC performance, with solar energy considered an effective method for solving environmental and energy crises. In recent years, research on incorporating photocatalysts into MFCs to improve power generation efficiency has increased; however, few studies have applied heterogeneous photo-Fenton cathodes to MFCs. Furthermore, the heterogeneous Fenton reaction requires the addition of hydrogen peroxide, increasing operating costs. Using an air cathode to generate hydrogen peroxide in situ would reduce operating costs. Simultaneously, to avoid electron competition between hydrogen peroxide production and the Fe(III) reduction reaction, a dual-cathode system is designed to ensure both the hydrogen peroxide production rate and the Fe(III) reduction rate. No research has been reported on coupling in-situ hydrogen peroxide production with the heterogeneous photo-Fenton reaction in photocatalytic microbial fuel cells to simultaneously improve power generation efficiency. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a device for efficient removal of pollutants by a dual-cathode photocatalytic microbial fuel cell.

[0005] The second objective of this invention is to provide a novel carbon cloth / polyaniline / CuFe2O4 microbial fuel cell photocathode electrode material and its preparation method.

[0006] The third objective of this invention is to provide a method for photocatalytic microbial fuel cells to efficiently remove pollutants from water while improving power generation performance.

[0007] The technical solution of this invention is summarized as follows:

[0008] A device for efficient pollutant removal using a dual-cathode photocatalytic microbial fuel cell includes a reactor body, which is divided into a cathode chamber and an anode chamber by a proton exchange membrane. A light source, which can be any light source, is installed on the outside of the cathode chamber. A circulation system runs through the cathode chamber, and a first valve is installed on the connecting pipe at the cathode chamber inlet. A peristaltic pump, a water detector, and a second valve are installed on the connecting pipe at the cathode chamber outlet. The photocathode surface of the reactor is made of quartz glass for receiving light. The photocathode is connected to the anode carbon brush via a wire and a resistor. An air cathode is connected to the anode carbon brush via a wire and a resistor of 10–10000 Ω. The anode chamber inlet and outlet are used for anolyte replacement, and microorganisms grow on the carbon brush.

[0009] The photocatalytic cathode is prepared by the following method:

[0010] (1) The PANI / CP electrode is manufactured by cyclic voltammetry electrodeposition. In short, CP is immersed in a mixed solution containing 0.1-1M aniline monomer and 0.5-2M sulfuric acid; aniline is polymerized on CP, and CV electrodeposition is performed in a standard three-electrode system. CP, a Pt plate, and a saturated calomel electrode are used as the working electrode, counter electrode, and reference electrode, respectively. The potential range is -0.2 to 1.0 V, the scan rate is 10-50 mV / s, and the scan interval is 2-20 cycles.

[0011] PANI is short for polyaniline; CP is short for conductive substrate carbon paper.

[0012] (2) The PANI / CP / CuFe2O4 photocathode is synthesized via a typical lyothermal method. In short, a mixture of 1.35–6.75 g FeCl3 and 0.426–2.13 g CuCl2 is dissolved in 40–80 mL ethylene glycol to form a clear solution, followed by the addition of 3.6–7.2 g sodium citrate and 1.0–2.0 g polyethylene glycol 10000. After vigorous stirring for 10–30 minutes, the mixture and the aforementioned PANI / CP electrode are transferred to a PTFE-lined stainless steel autoclave and maintained at 180–200 °C for 6–8 hours. The autoclave is then washed with distilled water and dried in a vacuum oven at 50–80 °C.

[0013] The air cathode is manufactured using the following method:

[0014] The preparation methods for sulfur- and chlorine-doped nitrogen- and carbon compounds are as follows:

[0015] Mix 0.1g-1g thiourea and 0.081g-0.3g sodium citrate evenly in a mortar and grind for 5-10 minutes. Transfer the mixture to a polytetrafluoroethylene-lined autoclave, which is filled with 0.1-0.5mL HCl and deionized water to 80% (100mL) of the autoclave's capacity. Heat the autoclave at 150-180℃ for 1-3 hours in a drying oven. After natural cooling, wash the resulting pale yellow solution with ethanol and centrifuge three times at 12000rpm. Dialyze the prepared sample in pure water using a dialysis membrane for 24 hours. Sulfur-chlorine doped nitrogen-carbon compounds are obtained by freeze-drying the dialysis solution.

[0016] The air cathode consists of a catalyst layer and a gas diffusion layer, with a stainless steel mesh as the substrate. Catalyst layer: 0.5–4.8 g of carbon black, 0.1–1 g of sulfur-chlorine-doped nitrogen-carbon compound, and 1.2–3.5 g of graphite are weighed and dispersed in 30–50 mL of ethanol in a beaker, and the mixture is ultrasonically incubated at room temperature for 10–20 minutes. 1–10 g of 60% PTFE emulsion is slowly added to the mixture as a binder. The mixture is stirred at 60–80 °C to obtain a dough-like paste. The paste is rolled into a 0.2–0.5 mm thick catalyst layer film, and then rolled onto one side of the stainless steel mesh to form a flat plate. Gas diffusion layer: 4–10 g of carbon black and 9–22.5 g of PTFE emulsion are mixed and rolled into a 0.2–0.5 mm thick film. The gas diffusion layer is rolled onto the other side of the stainless steel mesh to form an air cathode with a total thickness of 0.4–1 cm. The final air cathode is then formed after heating at 300–350 °C for 10–30 minutes.

[0017] PTFE is short for polytetrafluoroethylene.

[0018] A method for removing pollutants using a dual-cathode microbial fuel cell includes the following steps:

[0019] (1) A device for efficiently removing water pollutants using the above-mentioned dual-cathode microbial fuel cell;

[0020] (2) According to the proportion, add 0.1L to 0.3L of anaerobic sludge obtained from the sewage treatment plant and carbon brush 2 to 0.1L to 1L of simulated wastewater to obtain anolyte, and let it stand for 3 to 8 days to cultivate biofilm;

[0021] (3) Open the first valve, introduce water containing pollutants, close the first valve, turn on the light source, turn on the peristaltic pump, and react for 3 to 8 hours;

[0022] (4) Use a detector to check the wastewater treatment effect. When the pollutant concentration in the wastewater is lower than 0.01 mg / L, close the first valve, open the second valve, and discharge the purified water.

[0023] The simulated wastewater used in this invention comprises: 1 g / L sodium acetate, 0.02 g / L CaCl2, 0.31 g / L NH4Cl, 4.576 g / L Na2HPO4, 2.1323 g / L Na2HPO4, 0.021 g / L MgSO4, with the remainder being water.

[0024] The cathode contaminants used in this invention include antibiotics, organic dyes, and pharmaceuticals.

[0025] Advantages of this invention:

[0026] This invention combines photocatalysis with MFC to improve the removal of pollutants from water. The introduction of a photocathode converts light energy into electrical energy, reducing device resistance and thus increasing overall power generation. The photocathode used in this invention is a novel carbon cloth / polyaniline / CuFe2O4, which solves the problem of low light absorption efficiency. Polyaniline modification increases the loading of CuFe2O4, improves light absorption, and promotes charge transfer. Electrons generated at the anode help reduce the recombination of electrons and holes in the catalyst, greatly improving photocatalytic activity. Preparing the photocatalyst as a photocathode avoids the difficulty of recovering powdered catalysts. The air cathode can utilize electrons generated at the anode to undergo an oxygen reduction reaction, producing H2O2 in situ. The addition of sulfur, chlorine, nitrogen, and carbon doped compounds increases the rate of H2O2 production at the air cathode. The dual-cathode design ensures the production rate of hydrogen peroxide and the Fe(III) reduction reaction rate. The photocathode can activate H2O2, generating a large amount of -OH, accelerating pollutant removal.

[0027] This invention improves the overall operating efficiency of the battery by preparing two cathodes; it features simple equipment structure, high efficiency, and low cost, and can achieve energy recovery from wastewater while reducing the negative impact of pollutants on the environment. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a device for efficient pollutant removal using a dual-cathode photocatalytic microbial fuel cell according to the present invention. The components are: 1. Microorganisms; 2. Carbon brush; 3. Anode chamber; 4. Air cathode; 5. Cathode chamber; 6. Quartz glass; 7. Photocathode; 8. Cathode chamber inlet; 9. Cathode chamber outlet; 10. First valve; 11. Resistor I; 12. Resistor II; 13. Light source; 14. Second valve; 15. Peristaltic pump; 16. Proton exchange membrane; 17. Anode chamber inlet; 18. Anode chamber outlet; 19. Water detector; 20. Reactor body.

[0029] Figure 2 The image shows the IT diagram of the PANI / CP / CuFe2O4 composite photocathode.

[0030] Figure 3 This is a power density diagram of a photocatalytic microbial fuel cell for efficiently removing organic pollutants.

[0031] Figure 4 This is a degradation diagram of a photocatalytic microbial fuel cell that efficiently removes various organic pollutants. Detailed Implementation

[0032] The present invention will be further described below through specific embodiments.

[0033] The following examples are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way.

[0034] The simulated wastewater used in this invention comprises: 1 g / L sodium acetate, 0.02 g / L CaCl2, 0.31 g / L NH4Cl, 4.576 g / L Na2HPO4, 2.1323 g / L Na2HPO4, 0.019 g / L MgSO4, with the remainder being water.

[0035] The anaerobic sludge obtained by the water treatment plant comes from the Tianjin Wastewater Treatment Plant.

[0036] The present invention will be further described with reference to the embodiments and accompanying drawings.

[0037] Example 1

[0038] The photocathode is made using the following method:

[0039] (1) Fabrication of PANI / CP electrode:

[0040] A CP (5.0 × 1.0 × 0.1 cm) was immersed in a mixed solution containing 0.1 M aniline monomer and 1 M H2SO4; aniline was polymerized on the CP using a CV electrodeposition process in a standard three-electrode system, with CP, a Pt plate, and a saturated calomel electrode used as the working electrode, counter electrode, and reference electrode, respectively. The potential range was -0.2 to 1.0 V, the scan rate was 10 mV / s, and the scan segment consisted of 5 cycles.

[0041] (2) Fabrication of PANI / CP / CuFe2O4 photocathode:

[0042] A mixture of 1.35 g FeCl3 and 0.426 g CuCl2 was dissolved in 40 mL ethylene glycol to form a clear solution, followed by the mixing of 1.8 g sodium citrate and 0.5 g polyethylene glycol 10000. After vigorous stirring for 30 minutes, the mixture and the aforementioned PANI / CP electrode were transferred to a stainless steel autoclave lined with polytetrafluoroethylene and maintained at 200 °C for 8 hours. The autoclave was then washed with distilled water and dried in a vacuum oven at 80 °C.

[0043] (3) Air cathode preparation:

[0044] 0.5 g thiourea and 0.081 g sodium citrate were mixed evenly and ground in a mortar for 5 minutes. The mixture was then transferred to a polytetrafluoroethylene-lined autoclave, which was filled with 0.1 mL HCl and deionized water to 80% (100 mL) of the autoclave's capacity. The autoclave was heated at 150 °C for 2 hours in a drying oven. After natural cooling, the resulting pale yellow solution was washed with ethanol and centrifuged three times at 12,000 rpm. The prepared sample was dialyzed in pure water for 24 hours using a dialysis membrane. The sulfur-chlorine-doped nitrogen-carbon compound was obtained by freeze-drying the dialysate.

[0045] Catalytic layer: Weigh 2g of carbon black, 0.1g of sulfur-chlorine-doped nitrogen-carbon compound, and 0.5g of graphite and disperse them separately in 30mL of ethanol in a beaker. In an ultrasonic bath at room temperature, continue for 20 minutes. Slowly add 3g of 60% PTFE emulsion as a binder to the mixture. Stir the mixture at 60°C to obtain a dough-like paste. Roll the paste into a 0.3mm thick catalytic layer film, and then roll it onto one side of the stainless steel mesh to form a flat plate. Gas diffusion layer: Mix 4g of carbon black and 9g of PTFE emulsion and roll it into a 0.3mm thick film. Roll the gas diffusion layer onto the other side of the stainless steel mesh to form an air cathode with a total thickness of 6mm. Then heat at 340°C for 30 minutes to form the final air cathode.

[0046] Example 2

[0047] The photocathode is made using the following method:

[0048] (1) Fabrication of PANI / CP electrode:

[0049] The CP (4.0×2.0×0.1cm) was immersed in a mixed solution containing 0.5M aniline monomer and 1M H2SO4; for aniline, polymerization was carried out on the CP using CV electrodeposition in a standard three-electrode system, with CP, Pt plate and saturated calomel electrode used as working electrode, counter electrode and reference electrode respectively, the potential range was -0.2 to 1.0 V, the scan rate was 20mV / s and the scan segment was 3 cycles;

[0050] (2) Fabrication of PANI / CP / CuFe2O4 photocathode:

[0051] In short, a mixture of 4.05 g FeCl3 and 1.278 g CuCl2 was dissolved in 60 mL ethylene glycol to form a clear solution, followed by the addition of 3.6 g sodium citrate and 1.0 g polyethylene glycol 10000. After vigorous stirring for 30 minutes, the mixture and the aforementioned PANI / CP electrode were transferred to a PTFE-lined stainless steel autoclave and maintained at 180 °C for 8 hours. The autoclave was then washed with distilled water and dried in a vacuum oven at 80 °C.

[0052] (3) Air cathode preparation:

[0053] 1 g of thiourea and 0.3 g of sodium citrate were mixed evenly and ground in a mortar for 8 minutes. The mixture was then transferred to a high-pressure autoclave lined with polytetrafluoroethylene, which was filled with 0.5 mL of HCl and deionized water to 80% (100 mL) of the autoclave capacity. The autoclave was heated at 150 °C for 3 hours in a drying oven. After natural cooling, the resulting pale yellow solution was washed with ethanol and centrifuged three times at 12,000 rpm. The prepared sample was dialyzed in pure water for 24 hours using a dialysis membrane. The sulfur-chlorine-doped nitrogen-carbon compound was obtained by freeze-drying the dialysate.

[0054] Catalytic layer: Weigh 4g carbon black, 0.3g sulfur-chlorine-doped nitrogen-carbon compound, and 1g graphite and disperse them separately in 30mL of ethanol in a beaker. In an ultrasonic bath at room temperature, continue for 20 minutes. Slowly add 5g of 60% PTFE emulsion as a binder to the mixture. Stir the mixture at 60°C to obtain a dough-like paste. Roll the paste into a 0.5mm thick catalytic layer film, and then roll it onto one side of the stainless steel mesh to form a flat plate. Gas diffusion layer: Mix 6g carbon black and 13.5g PTFE emulsion and roll it into a 0.5mm thick film. Roll the gas diffusion layer onto the other side of the stainless steel mesh to form an air cathode with a total thickness of 10mm. Then heat at 350°C for 30 minutes to form the final air cathode.

[0055] Example 3

[0056] The photocathode is made using the following method:

[0057] (1) Fabrication of PANI / CP electrode:

[0058] A CP (2.0 × 3.0 × 0.1 cm) was immersed in a mixed solution containing 0.3 M aniline monomer and 1 M H2SO4; aniline was polymerized on the CP using a CV electrodeposition process in a standard three-electrode system, with CP, a Pt plate, and a saturated calomel electrode (SCE) used as the working electrode, counter electrode, and reference electrode, respectively. The potential range was -0.2 to 1.0 V, the scan rate was 10 mV / s, and the scan segment consisted of 5 cycles.

[0059] (2) Fabrication of PANI / CP / CuFe2O4 photocathode:

[0060] A mixture of 2 g FeCl3 and 0.63 g CuCl2 was dissolved in 60 mL ethylene glycol to form a clear solution, followed by the mixing of 1.8 g sodium citrate and 0.5 g polyethylene glycol 10000. After vigorous stirring for 30 minutes, the mixture and the aforementioned PANI / CP electrode were transferred to a stainless steel autoclave lined with polytetrafluoroethylene and maintained at 180 °C for 8 hours. The autoclave was then washed with distilled water and dried in a vacuum oven at 80 °C.

[0061] (3) Air cathode preparation:

[0062] 0.5 g of thiourea and 0.1 g of sodium citrate were mixed evenly and ground in a mortar for 10 minutes. The mixture was then transferred to a polytetrafluoroethylene-lined autoclave, which was filled with 0.3 mL of HCl and deionized water to 80% (100 mL) of the autoclave's capacity. The autoclave was heated at 180 °C for 3 hours in a drying oven. After natural cooling, the resulting pale yellow solution was washed with ethanol and centrifuged three times at 12,000 rpm. The prepared sample was dialyzed in pure water for 24 hours using a dialysis membrane. The sulfur-chlorine-doped nitrogen-carbon compound was obtained by freeze-drying the dialysate.

[0063] Catalytic layer: Weigh 2g of carbon black, 0.3g of sulfur-chlorine-doped nitrogen-carbon compound, and 0.5g of graphite and disperse them separately in 20mL of ethanol in a beaker. In an ultrasonic bath at room temperature, continue for 15 minutes. Slowly add 3g of 60% PTFE emulsion as a binder to the mixture. Stir the mixture at 60°C to obtain a dough-like paste. Roll the paste into a 5mm thick catalytic layer film, and then roll it onto one side of the stainless steel mesh to form a flat plate. Gas diffusion layer: Mix 8g of carbon black and 18g of PTFE emulsion and roll it into a 5mm thick film. Roll the gas diffusion layer onto the other side of the stainless steel mesh to form an air cathode with a total thickness of 10mm. Then heat at 350°C for 30 minutes to form the final air cathode.

[0064] Example 4

[0065] A device for efficient pollutant removal using a dual-cathode photocatalytic microbial fuel cell includes a reactor body 20, which is divided into a cathode chamber 5 and an anode chamber 3 by a proton exchange membrane 16. A light source 13 is installed on the outside of the cathode chamber 5, and the light source can be any light source. A circulation system runs through the cathode chamber, and a first valve 10 is installed on the connecting pipe of the cathode chamber inlet 8. A peristaltic pump 15, a water detector 19, and a second valve 14 are installed on the connecting pipe of the cathode chamber outlet 9. The photocathode surface of the reactor is made of quartz glass 6, which is used for the photocathode 7 to receive light. The photocathode 7 (prepared in Example 1) is connected to the anode carbon brush 2 through a wire and a resistor 11. The air cathode 4 (prepared in Example 1) is connected to the anode carbon brush 2 through a wire and a resistor 12, and the resistor is 10-10000Ω. The anode chamber inlet 17 and the anode chamber outlet 18 are used for anolyte replacement, and microorganisms 1 grow on the carbon brush 2.

[0066] Example 5

[0067] A device for efficient removal of pollutants using a dual-cathode photocatalytic microbial fuel cell (see...) Figure 1 The photocathode 7 (prepared in Example 2) and the air cathode 4 (prepared in Example 2) are the same as in Example 4.

[0068] Example 6

[0069] A device for efficient removal of pollutants using a dual-cathode photocatalytic microbial fuel cell (see...) Figure 1 The photocathode 7 (prepared in Example 3) and the air cathode 4 (prepared in Example 3) are the same as in Example 4.

[0070] Example 7

[0071] A method for efficiently removing pollutants using a dual-cathode photocatalytic microbial fuel cell includes the following steps:

[0072] (1) A device for efficient removal of pollutants using a dual-cathode photocatalytic microbial fuel cell according to Example 4, see Figure 1 The reactor body 20 is a double-chamber cubic sealed box. Its anode chamber is 10cm long, 10cm wide, and 10cm high. Its cathode chamber is 10cm long, 10cm wide, and 10cm high. The anode is a carbon brush (brush bristle diameter 3cm × length 3cm, total length 12cm). The simulated sunlight lamp is 100W.

[0073] (2) Add 0.1L of anaerobic sludge and carbon brush obtained from the sewage treatment plant to 0.9L of nutrient solution to obtain anode chamber 3. Pass the anolyte into anode chamber 3 through anode chamber inlet 18, seal and place for 7 days to cultivate biofilm.

[0074] (3) Open the first valve 10. Taking tetracycline as an example, introduce 1L of 10mg / L tetracycline wastewater, turn on the peristaltic pump 15 and the second valve 14, turn on the simulated sunlight lamp 13, and react for 3 hours. During the reaction, the air cathode will generate H2O2 in situ, and the photocathode will use H2O2 to generate free radicals, thereby eliminating pollutants in the water.

[0075] (4) The tetracycline treatment effect was detected using detector 19. When the tetracycline concentration was below 10 μg / L, the first valve 10 was closed, the second valve 14 was opened, and the treated water was discharged. The tetracycline degradation effect was as follows: Figure 4 As shown.

[0076] Example 8

[0077] A method for efficiently removing pollutants using a dual-cathode photocatalytic microbial fuel cell includes the following steps:

[0078] A device for efficiently removing pollutants using a dual-cathode photocatalytic microbial fuel cell, as described in Example 4, is shown below. Figure 1 The reactor body 20 is a double-chambered cubic sealed box, with its anode chamber measuring 10 cm in length and 10 cm in width. The cathode chamber is 10cm long, 10cm wide, and 10cm high; the anode is a carbon brush (brush diameter 3cm × length 3cm, total length 12cm) simulating a 100W sunlight lamp; 0.2L of anaerobic sludge obtained from a wastewater treatment plant and the carbon brush are added to 0.8L of nutrient solution to obtain anode chamber 3. The anolyte is introduced into anode chamber 3 through anode chamber inlet 18, sealed and placed for 5 days to cultivate the biofilm; the first valve 10 is opened, and taking Rhodamine B as an example, 1L of 10mg / L Rhodamine B wastewater is introduced, the peristaltic pump 15 and the second valve 14 are turned on, the ultraviolet lamp 13 is turned on, and the reaction is carried out for 3 hours; during the reaction, the air cathode will generate H2O2 in situ, and the photocathode will use H2O2 to generate free radicals, thereby eliminating pollutants in the water; the Rhodamine B treatment effect is detected by detector 19. When the Rhodamine B concentration is lower than 10μg / L, the first valve 10 is closed, the second valve 14 is opened, and the treated water is discharged. Tetracycline degradation effect as follows Figure 4 As shown.

[0079] Example 9

[0080] A method for efficiently removing pollutants using a dual-cathode photocatalytic microbial fuel cell includes the following steps:

[0081] (1) A device for efficient removal of pollutants using a dual-cathode photocatalytic microbial fuel cell according to Example 4, see Figure 1The reactor body 20 is a double-chamber cubic sealed box. Its anode chamber is 10cm long, 10cm wide, and 10cm high. Its cathode chamber is 10cm long, 10cm wide, and 10cm high. The anode is a carbon brush (brush bristle diameter 3cm × length 3cm, total length 12cm). The visible light lamp is 100W.

[0082] (2) Add 0.05L of anaerobic sludge and carbon brush obtained from the sewage treatment plant to 0.9L of nutrient solution to obtain anode chamber 3. Introduce anolyte into anode chamber 3 through anode chamber inlet 18, seal and place for 10 days to cultivate biofilm.

[0083] (3) Open the first valve 10, take chloroquine phosphate as an example, introduce 1L of 10mg / L chloroquine phosphate wastewater, open the peristaltic pump 15 and the second valve 14, turn on the simulated sunlight lamp 13, and react for 3 hours; during the reaction, the air cathode will generate H2O2 in situ, and the photocathode will use H2O2 to generate free radicals, thereby eliminating pollutants in the water.

[0084] (4) The treatment effect of chloroquine phosphate was detected using detector 19. When the concentration of chloroquine phosphate was below 10 μg / L, the first valve 10 was closed and the second valve 14 was opened, and the treated water was discharged. The tetracycline degradation effect was as follows: Figure 4 As shown.

[0085] Example 10

[0086] Photocatalytic air cathode photoelectric response performance in photocatalytic MFC

[0087] Using the dual-cathode photocatalytic microbial fuel cell device of Example 4 for efficient pollutant removal, the PANI / CP / CuFe2O4 photocathode and carbon brush anode were connected to an electrochemical workstation via wires. The photoelectric response performance was tested, and the results are as follows: Figure 2 As shown, the prepared PANI / CP / CuFe2O4 photocathode was found to have good photoelectric response in photocatalytic MFC.

Claims

1. A device for efficient removal of pollutants by a dual-cathode photocatalytic microbial fuel cell, comprising a reactor body (20) divided into a cathode chamber (5) and an anode chamber (3) by a proton exchange membrane (16); a light source (13) is arranged outside the cathode chamber (5); a circulation system penetrates the cathode chamber (5), a first valve (10) is arranged on the connecting pipe of the cathode chamber water inlet (8); a peristaltic pump (15), a water detector (19) and a second valve (14) are arranged on the connecting pipe of the cathode chamber water outlet (9); the photoelectric cathode surface of the reactor is quartz glass (6) for the photoelectric cathode (7) to receive light; the photoelectric cathode (7) is connected with the anode carbon brush (2) through a wire and a resistance one (11); the air cathode (4) is connected with the anode carbon brush (2) through a wire and a resistance two (12), and the resistance is 10-10000Ω; the anode chamber water inlet (17) and the anode chamber water outlet (18) are used for anode liquid replacement, and the microorganism (1) grows on the anode carbon brush (2); The photoelectric cathode (7) is prepared according to the following steps: (1) Preparation of PANI / CP electrode: According to the proportion, CP is immersed in a mixed solution containing 0.1-1M aniline monomer and 0.5-2M sulfuric acid; aniline is polymerized on CP, and CV electrodeposition process is used in a standard three-electrode system, using CP, Pt plate and saturated calomel electrode as working electrode, counter electrode and reference electrode respectively, the potential range is-0.2-1.0V, the scanning rate is 10-50mV / s, and the scanning section is 2-20 cycles; PANI is the abbreviation of polyaniline; CP is the abbreviation of conductive base material carbon paper; (2) Preparation of PANI / CP / CuFe2O4 photoelectric cathode: According to the proportion, a mixture of 1.35-6.75g FeCl3 and 0.426-2.13g CuCl2 is dissolved in 40-80mL ethylene glycol to form a clear solution, then 3.6-7.2g sodium citrate and 1.0-2.0g polyethylene glycol 10000 are mixed; after 10-30 minutes of vigorous stirring, the mixture and the PANI / CP electrode prepared in step (1) above are transferred to a stainless steel autoclave lined with polytetrafluoroethylene, and kept at 180-200℃ for 6-8 hours, washed with distilled water and dried in a vacuum oven at 50-80℃.

2. The device for high efficient removal of pollutants by dual-cathode photocatalytic microbial fuel cell according to claim 1, wherein, The air cathode (4) is composed of a catalytic layer and a gas diffusion layer, and a stainless steel mesh is used as the substrate; Preparation of the catalytic layer: 0.5-4.8g carbon black, 0.01-0.5g sulfur-chlorine-doped nitrogen-carbon compound and 1.2-3.5g graphite are weighed and dispersed into 30-50mL ethanol in a beaker, and 1-10g 60% PTFE emulsion is slowly added to the mixture as a binder under ultrasonic bath at room temperature for 10-20 minutes, and the mixture is stirred at 60-80℃ to obtain a dough-like paste, and the paste is rolled into a 0.2-0.5mm catalytic layer film; The catalytic layer is rolled on one side of the above-mentioned stainless steel mesh to be a flat plate; The preparation of the gas diffusion layer: 4-10 g of carbon black and 9-22.5 g of PTFE emulsion are mixed and rolled into a thin film of 0.2-0.5 mm; The gas diffusion layer is rolled onto the other side of the above-mentioned stainless steel mesh to form an air cathode with a total thickness of 0.4-1 cm, and then after heating at 300-350°C for 10-30 minutes, the final air cathode (4) is formed; The PTFE is the abbreviation of polytetrafluoroethylene.

3. The device for high efficient removal of pollutants by dual-cathode photocatalytic microbial fuel cell according to claim 2, characterized in that, The sulfur-chlorine doped nitrogen-carbon compound is prepared according to the following steps: Proportionally, 0.1 g-1 g of thiourea and 0.081 g-0.3 g of sodium citrate are uniformly mixed and ground in a mortar for 5-10 minutes; the mixture is transferred to a polytetrafluoroethylene-lined autoclave containing 0.1-0.5 mL of HCl and deionized water to 80% of the autoclave capacity, and heated at 150-180°C in a dry box for 1-3 hours; after natural cooling, the obtained light yellow solution is washed with ethanol, centrifuged at 12000 rpm for 3 times, and the prepared sample is dialyzed in pure water for 24 h using a dialysis membrane, and the sulfur-chlorine doped nitrogen-carbon compound is obtained by freeze-drying process of the dialysis solution.

4. The device for high efficient removal of pollutants by dual-cathode photocatalytic microbial fuel cell according to claim 1, wherein, The light source is any light source.

5. A method for efficient removal of pollutants by a dual-cathode photocatalytic microbial fuel cell, characterized by the following steps: (1) using the device for efficient removal of water pollutants by a dual-cathode microbial fuel cell according to claim 1; (2) proportionally, 0.1L-0.3L of anaerobic sludge obtained from a sewage treatment plant is placed in 0.1L-1L of wastewater to obtain an anode liquid with the anode carbon brush (2), and the culture of electricity-producing microbial membrane is placed for 3-8 days; (3) open the first valve (10), introduce the water body containing pollutants, close the first valve (10), turn on the light source (13), open the peristaltic pump (15), and react for 3-8 hours; (4) detect the wastewater treatment effect with the detector (19), when the concentration of pollutants in the wastewater is lower than 100 μg / L, close the first valve (10), open the second valve (14), and discharge the purified water body.

6. The method for high efficient removal of pollutants by double-cathode photocatalytic microbial fuel cell according to claim 5, characterized in that, The water body containing pollutants in step (3) includes antibiotics, organic dyes and drugs.

7. The method for high efficient removal of pollutants by dual-cathode photocatalytic microbial fuel cell according to claim 5, characterized in that, The pH of the water body containing pollutants is 3-10.

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