A catalytic-microbial coupling material, a preparation method thereof, an electrocatalytic-microbial coupling device and application thereof

Abstract

The application provides a catalysis-microorganism coupling material and a preparation method, an electrocatalysis-microorganism coupling device and application thereof, and belongs to the technical field of electrocatalysis materials.The catalysis-microorganism coupling material comprises a hydrophilic modified substrate, and microorganisms and catalysis materials loaded on the hydrophilic modified substrate; the microorganisms are a mixture of electrogenic microorganisms and anaerobic microorganisms, or the microorganisms are aerobic microorganisms; and the catalysis material is graphite phase carbon nitride doped with metal oxides.The electrocatalysis-microorganism coupling device prepared by using the catalysis-microorganism coupling material is used for treating polluted water bodies and / or polluted sediments, the voltage and current used are low, the energy consumption is less, the treatment effect is good, and the device is suitable for large-scale production and application.

Description

Technical Field

[0001] This invention relates to the field of electrocatalytic materials technology, specifically to a catalytic-microbial coupling material and its preparation method, an electrocatalytic-microbial coupling device and its application. Background Technology

[0002] With rapid economic and social development and rising living standards, the amount of pollutants is also increasing. Surface water pollution has attracted widespread attention from all sectors of society. Comprehensive treatment of surface water bodies, especially rivers, to improve water quality is of great significance.

[0003] Pollutants include exogenous and endogenous sources. Endogenous pollution includes water pollution and sediment pollution. Sediment pollution can lead to many serious problems, such as degradation of ecosystem function and biodiversity, excessive algae growth, foul odors in water bodies, and the death of aquatic plants and animals. To achieve long-term surface water environmental quality standards in water body remediation, it is necessary to treat not only the water body but also the sediment. Sediment remediation is generally divided into in-situ remediation and ex-situ remediation. Improper ex-situ remediation can easily cause secondary pollution, is costly, and can damage the original ecological environment. Compared with ex-situ remediation, in-situ remediation is easier to operate, lower in cost, and produces less secondary pollution. However, current traditional technologies lack effective long-term treatment methods for sediment that can be controlled. Therefore, finding a technology that can simultaneously treat water bodies and sediment and is easy to implement is of significant practical importance.

[0004] Currently, there are many studies on the application of electrocatalysis technology to highly polluted and high-load water bodies. Zhong Yifang et al. used an electrode catalysis system to degrade Acid Red (GR) dye wastewater (Zhong Yifang, Li Jiawen, et al. Comparative study on the degradation of Acid Red dye wastewater by Ti / PbO2 electrode and Ti / IrO2+Ta2O5 electrode catalysis systems [J]. Applied Chemical Industry, 2024, 43(1).); Zhang Guohui et al. used electrocatalytic oxidation to treat leachate wastewater from slag yards (Zhang Guohui, Huang Jianliang, et al. Study on the treatment of leachate wastewater from slag yards by electrocatalytic oxidation [J]. Applied Chemical Industry, 2024). However, the voltage used in the above methods is relatively high, resulting in high energy consumption; moreover, most of the above methods are used in sewage treatment plants, which is not conducive to widespread application. Summary of the Invention

[0005] The purpose of this invention is to provide a catalytic-microbial coupling material and its preparation method, an electrocatalytic-microbial coupling device and its application. When the electrocatalytic-microbial coupling device prepared by the catalytic-microbial coupling material provided by this invention is used for the treatment of polluted water and / or polluted sediment, the voltage and current used are low, the energy consumption is low, and the treatment effect is good, making it suitable for large-scale production and application.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a catalytic-microbe coupling material, comprising a hydrophilic modified substrate and microorganisms and a catalytic material loaded on the hydrophilic modified substrate, wherein the microorganisms are a mixture of electrogenic microorganisms and anaerobic microorganisms, or the microorganisms are aerobic microorganisms; and the catalytic material is graphitic carbon nitride doped with metal oxides.

[0008] Preferably, the hydrophilic modified substrate is obtained by modifying activated carbon felt with an acid reagent; the thickness of the activated carbon felt is 1-3 cm; the modification temperature is 25-28°C and the time is 20-28 h.

[0009] Preferably, the metal oxide comprises ZnO, NiO, or Fe2O3, and the doping amount of the metal element in the catalytic material is 0.1–0.3 wt%; the loading amount of the catalytic material in the catalytic-microbial coupling material is 2–5 g / m³. 2 .

[0010] Preferably, the microbial loading on the catalytic-microbial coupling material is 20–25 g / m³. 2 The mass ratio of electrogenic microorganisms to anaerobic microorganisms in the mixture of electrogenic microorganisms and anaerobic microorganisms is 1.5 to 2.5:1.

[0011] Preferably, the catalytic-microbial coupling material includes a first coupling material or a second coupling material; the doping amount of metal elements in the catalytic material on the first coupling material is 0.1 to 0.18 wt%, and the microorganisms are aerobic microorganisms; the doping amount of metal elements in the catalytic material on the second coupling material is 0.22 to 0.3 wt%, and the microorganisms are a mixture of electrogenic microorganisms and anaerobic microorganisms.

[0012] This invention provides a method for preparing the catalytic-microbial coupling material described in the above technical solution, comprising the following steps:

[0013] Microorganisms were mixed with a hydrophilic modified substrate and cultured to obtain a hydrophilic modified substrate loaded with microorganisms.

[0014] A catalytic material dispersion was coated onto the surface of the hydrophilic modified substrate loaded with microorganisms, and the resulting material was dried to obtain the catalytic-microorganism coupling material.

[0015] This invention provides the application of the catalytic-microbial coupling material described in the above technical solution or the catalytic-microbial coupling material prepared by the preparation method described in the above technical solution in the preparation of electrocatalytic-microbial anodes.

[0016] This invention provides an electrocatalytic-microbial coupling device, comprising a power supply device and a first cathode, a first anode, a second cathode, and a second anode arranged sequentially from top to bottom. The first cathode and the second cathode are connected to the negative electrode of the power supply device via wires, and the first anode and the second anode are connected to the positive electrode of the power supply device via wires.

[0017] The first anode and the second anode are independently the catalytic-microbial coupling material described in the above technical solution or the catalytic-microbial coupling material prepared by the preparation method described in the above technical solution, and the microorganisms loaded on the first anode are aerobic microorganisms, while the microorganisms loaded on the second anode are a mixture of electrogenic microorganisms and anaerobic microorganisms.

[0018] Preferably, the first cathode and the second cathode are graphite plates; the doping amount of metal elements in the catalytic material on the first anode is 0.1 to 0.18 wt%; and the doping amount of metal elements in the catalytic material on the second anode is 0.22 to 0.3 wt%.

[0019] This invention provides the application of the catalytic-microbial coupling material described in the above technical solution, the catalytic-microbial coupling material prepared by the preparation method described in the above technical solution, or the electrocatalytic-microbial coupling device described in the above technical solution in the treatment of polluted water bodies and / or polluted sediment.

[0020] This invention provides a catalytic-microbial coupling material, comprising a hydrophilic modified substrate and microorganisms and a catalytic material loaded on the hydrophilic modified substrate. The microorganisms are a mixture of electrogenic and anaerobic microorganisms, or the microorganisms are aerobic microorganisms. The catalytic material is graphitic carbon nitride doped with metal oxides. When using the catalytic-microbial coupling material provided by this invention to prepare an electrocatalytic-microbial coupling device for the treatment of polluted water and / or polluted sediment, the voltage and current used are low. The device operates at a voltage of 0.6–1V and a current of 5–10μA, resulting in low energy consumption. The weak current promotes microbial growth and has no adverse effects on aquatic animals, ensuring a certain level of safety. Furthermore, the electrocatalytic-microbial coupling device of this invention has a reasonable structural design, facilitating simultaneous in-situ purification of water and sediment. For example, it can be directly placed in rivers, lakes, and other areas for in-situ treatment, reducing pollutants in wastewater and sediment, purifying water quality, and the voltage and current used have no impact on aquatic plants and animals. Furthermore, the electrocatalysis-microbial coupling device in this invention has good biocompatibility, high stability, visible light response, low cost, and is suitable for large-scale mass production and application. Attached Figure Description

[0021] Figure 1 The graph shows the removal effect of six catalytic materials on Rhodamine B in Test Example 1.

[0022] Figure 2 This is a schematic diagram of the experiment in Test Example 2;

[0023] Figure 3 The graph shows the COD removal rate test results of each coupling device used in Test Example 2;

[0024] Figure 4 The graph shows the ammonia nitrogen removal rate test results of each coupling device used in Test Example 2;

[0025] Figure 5 The graph shows the organic matter removal rate test results of each coupling device used in Test Example 2;

[0026] Figure 6 The graph shows the COD removal rate test results of the No. 2 coupling device and the No. 4 electrocatalytic device used in Test Example 3;

[0027] Figure 7 The graph shows the ammonia nitrogen removal rate test results of the No. 2 coupling device and the No. 4 electrocatalytic device used in Test Example 3;

[0028] Figure 8 The figure shows the current test results when the No. 2 coupling device was used to treat the southern section of the Ligang River in Jiangyin in Test Example 4.

[0029] Figure 9 The figure shows the COD removal rate test results when the No. 2 coupling device was used to treat the southern section of the Ligang River in Jiangyin in Test Example 4.

[0030] Figure 10 The figure shows the test results of ammonia nitrogen removal rate when using coupling device #2 to treat the southern section of the Ligang River in Jiangyin in Test Example 4;

[0031] Figure 11 The figure shows the test results of the organic matter removal rate in the bottom sediment of the Jiangyin Ligang River South Section when the No. 2 coupling device was used to treat the river in Test Example 4.

[0032] Figure 12 This is a comparison of the water quality before and after the treatment of the Jiangyin Ligang South Section River using the No. 2 coupling device in Test Example 4. Detailed Implementation

[0033] This invention provides a catalytic-microbe coupling material, comprising a hydrophilic modified substrate and microorganisms and a catalytic material loaded on the hydrophilic modified substrate, wherein the microorganisms are a mixture of electrogenic microorganisms and anaerobic microorganisms, or the microorganisms are aerobic microorganisms; and the catalytic material is graphitic carbon nitride doped with metal oxides.

[0034] In this invention, unless otherwise specified, all raw materials used are commercially available products well known to those skilled in the art or prepared using methods well known to those skilled in the art.

[0035] The catalytic-microbial coupling material provided by this invention includes a hydrophilic modified substrate, preferably obtained by modifying activated carbon felt with an acid reagent. In this invention, the thickness of the activated carbon felt is preferably 1–3 cm, more preferably 1–2 cm. Preferably, the activated carbon felt is washed and dried sequentially, then immersed in an acid reagent for modification to obtain the hydrophilic modified substrate. This invention does not have specific limitations on the washing and drying processes; methods well-known to those skilled in the art can be used. In this invention, the acid reagent preferably includes sulfuric acid, preferably prepared from concentrated sulfuric acid and water, with a concentration preferably 98 wt%; the volume ratio of concentrated sulfuric acid to water is preferably 1:1–3, more preferably 1:1; the modification temperature is preferably 25–28°C, more preferably 25–26°C, and the modification time is preferably 20–28 h, more preferably 24 h. After modification, the modified activated carbon felt is preferably taken out and washed and dried sequentially. The washing is preferably done with water to thoroughly remove residual acid reagents. The drying temperature is preferably 50–70°C, more preferably 60°C, and the drying time is preferably 20–28 hours, more preferably 24 hours. In this invention, the activated carbon felt has good electrical conductivity. Modification increases the hydrophilic groups and specific surface area on the surface of the activated carbon felt, which is beneficial for increasing the microbial loading capacity.

[0036] The catalytic-microbial coupling material provided by this invention includes a catalytic material supported on the hydrophilic modified substrate, wherein the catalytic material is graphitic carbon nitride doped with metal oxides. In this invention, the metal oxide preferably includes ZnO, NiO, or Fe2O3, more preferably ZnO; in this invention, the doping amount of the metal element in the catalytic material is preferably 0.1–0.3 wt%, specifically 0.1 wt%, 0.12 wt%, 0.15 wt%, 0.18 wt%, 0.2 wt%, 0.22 wt%, 0.25 wt%, 0.28 wt%, or 0.3 wt%; the loading amount of the catalytic material in the catalytic-microbial coupling material is preferably 2–5 g / m³. 2 Specifically, it can be 2g / m 2 3g / m 2 4g / m 2 or 5g / m 2In this invention, the preparation method of the catalytic material preferably includes the following steps: mixing graphitic carbon nitride with a metal precursor and performing a first calcination to obtain the catalytic material. In this invention, the graphitic carbon nitride is preferably prepared from urea through a second calcination; the temperature of the second calcination is preferably 440–460°C, more preferably 450°C; the time is preferably 1.5–2.5 h, more preferably 2 h; the second calcination is preferably carried out in an air atmosphere. In this invention, the metal precursor is preferably zinc acetate, iron acetate, or nickel acetate; the mass ratio of the metal precursor to the graphitic carbon nitride is based on ensuring the required amount of metal element doping in the catalytic material. In this invention, the mixing of the graphitic carbon nitride and the metal precursor is preferably ball milling, and the ball milling aid used is preferably ethanol; the ball milling speed is preferably 900-1100 r / min, more preferably 1000 r / min, and the time is preferably 5-15 min, more preferably 10 min; the ball milling mixture preferably further includes drying, and the drying temperature is preferably 75-85℃, more preferably 80℃. The first calcination temperature is preferably 440-460℃, more preferably 450℃; the time is preferably 0.5-1.5 h, more preferably 1 h; the first calcination is preferably carried out in an air atmosphere. This invention utilizes a mixed calcination method to dope metal oxides into the interior of graphitic carbon nitride, which is beneficial for broadening the spectral response range and can greatly improve the removal effect of pollutants.

[0037] The catalytic-microbial coupling material provided by this invention comprises microorganisms loaded on the hydrophilic modified substrate. The microorganisms are a mixture of electrogenic and anaerobic microorganisms, or the microorganisms are aerobic microorganisms. In this invention, the preferred microbial loading on the catalytic-microbial coupling material is 20–25 g / m³. 2 Specifically, it can be 20g / m 2 21g / m 2 22g / m 2 23g / m 2 24g / m 2 Or 25g / m 2The mass ratio of electrogenic microorganisms to anaerobic microorganisms in the mixture of electrogenic and anaerobic microorganisms is preferably 1.5–2.5:1, more preferably 2:1. In this invention, the aerobic microorganisms preferably include nitrifying bacteria and / or Proteus bacteria; the electrogenic microorganisms preferably include one or more of Shewanella, Proteus bacteria, and Gram-negative bacteria, possessing certain electrochemical activity; the anaerobic microorganisms preferably include denitrifying bacteria and / or yeast. In this invention, the aerobic, electrogenic, and anaerobic microorganisms are preferably enriched and cultured from the bottom sediment of the water body to be treated, such as rivers and lakes. The aerobic, electrogenic, and anaerobic microorganisms in this invention are preferably in-situ river and lake microorganisms, not genetically modified, and applied to river and lake treatment, posing no risk of biological invasion and will not pollute the treated river and lake environment. A detailed description follows.

[0038] In this invention, the method for preparing the aerobic microorganism preferably includes the following steps:

[0039] The bottom sediment is mixed with water for acclimatization to obtain an acclimatized mud-water mixture; the acclimatized mud-water mixture is mixed with a culture medium and enriched in an oxygen-rich atmosphere to obtain the aerobic microorganisms.

[0040] In this invention, the sediment is preferably subjected to initial screening to remove large particles, and then mixed with water for acclimatization. The preferred mass ratio of sediment to water is 1:2.5–3.5, more preferably 1:3; the preferred acclimatization temperature is 20–30°C, more preferably 25°C, and the preferred acclimatization time is 5–9 days, more preferably 7 days. After acclimatization, the preferred method is to mix the intermediate sediment-water mixture with a culture medium and conduct enrichment culture in an oxygen-enriched atmosphere; the oxygen-enriched atmosphere is preferably air. Specifically, the intermediate sediment-water mixture is inoculated into a sterile culture medium and placed in an Erlenmeyer flask, the flask opening is sealed with sterile tissue sealing film, and enrichment culture is performed. The enrichment culture of this invention is preferably performed 4 to 5 times, wherein the first enrichment culture is preferably performed for 12 to 17 days, more preferably 15 days; the subsequent enrichment cultures are preferably performed for 20 to 25 days, more preferably 23 days; other conditions for each enrichment culture are independently provided, including: temperature preferably 20 to 30°C, more preferably 25°C; pH preferably 8.0 ± 0.2; stirring speed preferably 150 to 170 r / min, more preferably 160 r / min. In this invention, after each enrichment culture, the supernatant is preferably removed by centrifugation, and the precipitated bacterial cells are rinsed again in a conical flask with freshly prepared culture medium before the next enrichment culture is performed under the aforementioned conditions; the centrifugation speed for each centrifugation is preferably 5500 to 6500 r / min, more preferably 6000 r / min, and the time is preferably 5 to 15 min, more preferably 10 min. This invention preferably uses the above conditions for enrichment culture, which helps to ensure the activity of the bacterial strain. In an embodiment of the present invention, the number of colony-forming units (CFU) per milliliter of sample obtained after enrichment culture of aerobic microorganisms is preferably 4.12 × 10⁻⁶. 8 .

[0041] In this invention, the method for preparing the electrogenic microorganism preferably includes the following steps:

[0042] The sediment was mixed with a liquid culture medium to obtain wastewater; the anode of a bipolar chamber microbial fuel cell (MFC) was placed in the wastewater for enrichment culture, and the electrogenic microorganisms were obtained on the surface of the anode.

[0043] The volume ratio of the bottom sediment to the liquid culture medium in this invention is preferably 1:4.5 to 5.5, and more preferably 1:5. This invention utilizes a bipolar chamber microbial fuel cell (MFC) to enrich and cultivate electrogenic microorganisms. The two sides of the MFC are preferably equal-volume glass bottles, which are pre-sterilized by autoclaving. Preferably, a conductive and corrosion-resistant metal material, such as titanium, is used as the anode. The entire anode is immersed in the wastewater, allowing the electrogenic microorganisms to adhere to its surface. The anode chamber is sealed to prevent air from entering. Preferably, an unpolished high-purity graphite electrode is used as the cathode. The cathode chamber contains a phosphate buffer solution (preferably 0.2 mol / L) to maintain the pH value in the reaction tank at 6.8–7.2, increasing the solution's conductivity and reducing the battery's internal resistance. An aeration head is preferably provided at the bottom of the cathode for oxygenation and mixing. The two electrodes are preferably connected to a load resistor via a copper wire. The load resistor is preferably an adjustable resistance box. A digital multimeter is connected across the load resistor (with a stable resistance of 500 Ω) to monitor and record changes in the external circuit voltage online, collecting the electrogenic microorganisms attached to the anode surface. In an embodiment of the present invention, the number of CFUs (cells per liter of sample) of electrogenic microorganisms obtained after enrichment culture is preferably 1.45 × 10⁻⁶. 8 .

[0044] In this invention, the method for preparing the anaerobic microorganisms preferably includes the following steps:

[0045] The anaerobic microorganisms were obtained by mixing the sediment with a liquid culture medium and enriching them in an anaerobic atmosphere.

[0046] The volume ratio of sediment to liquid culture medium in this invention is preferably 1:4.5-5.5, more preferably 1:5. The anaerobic atmosphere in this invention is preferably an argon atmosphere. Specifically, this invention involves mixing sediment and liquid culture medium in a conical flask, purging the upper part of the flask with argon gas to remove air, and then performing enrichment culture. The enrichment culture is preferably performed 4-5 times, with the first enrichment culture preferably lasting 12-17 days, more preferably 15 days; subsequent enrichment cultures are preferably lasting 20-25 days, more preferably 23 days; other independent conditions for each enrichment culture include: a temperature preferably 25-35℃, more preferably 30℃; a pH value preferably 7.2±0.2; a stirring speed preferably 100-150 r / min, more preferably 120 r / min, and the stirring method is preferably intermittent stirring, specifically, continuous stirring for 10 hours every 6 hours. In this invention, after each enrichment culture, the supernatant is preferably removed by centrifugation, and the precipitated bacterial cells are rinsed again in a conical flask with freshly prepared culture medium before the next enrichment culture is performed under the aforementioned conditions. The centrifugation speed for each cycle is preferably 5500–6500 r / min, more preferably 6000 r / min, and the centrifugation time is preferably 5–15 min, more preferably 10 min. This invention preferably uses the above conditions for enrichment culture to ensure bacterial activity. In the embodiments of this invention, the number of colony-forming units (CFU) per milliliter of sample obtained after enrichment culture is preferably 2.74 × 10⁻⁶. 8 .

[0047] In this invention, specifically, the catalytic-microbial coupling material includes a first coupling material or a second coupling material. In this invention, the doping amount of metal elements in the catalytic material on the first coupling material is preferably 0.1–0.18 wt%, more preferably 0.1–0.12 wt%; the microorganisms on the first coupling material are preferably aerobic microorganisms. In this invention, the doping amount of metal elements in the catalytic material on the second coupling material is preferably 0.22–0.3 wt%, more preferably 0.28–0.3 wt%; the microorganisms on the second coupling material are preferably a mixture of electrogenic microorganisms and anaerobic microorganisms, wherein the mass ratio of electrogenic microorganisms to anaerobic microorganisms is preferably 1.5–2.5, more preferably 2:1.

[0048] This invention provides a method for preparing the catalytic-microbial coupling material described in the above technical solution, comprising the following steps:

[0049] Microorganisms were mixed with a hydrophilic modified substrate and cultured to obtain a hydrophilic modified substrate loaded with microorganisms.

[0050] A catalytic material dispersion was coated onto the surface of the hydrophilic modified substrate loaded with microorganisms, and the resulting material was dried to obtain the catalytic-microorganism coupling material.

[0051] This invention involves culturing microorganisms with a hydrophilic modified substrate to obtain a microbial-loaded hydrophilic modified substrate. In this invention, the culturing temperature is preferably 20–30°C, more preferably 25°C; the culturing time is preferably 7–10 days, more preferably 8 days, specifically based on ensuring that the microbial load meets the requirements. Preferably, after culturing, the hydrophilic modified substrate is removed and washed with water to remove excessive or unevenly loaded microorganisms from the surface of the substrate, which helps ensure the uniformity of subsequent catalytic material loading.

[0052] After obtaining the hydrophilic modified substrate loaded with microorganisms, the present invention coats the surface of the hydrophilic modified substrate loaded with microorganisms with a catalytic material dispersion, and after drying, obtains the catalytic-microorganism coupling material. In the present invention, the catalytic material dispersion preferably includes catalytic material, water, and polyethylene glycol; the mass ratio of the catalytic material, water, and polyethylene glycol is preferably 1:90-110:0.05-0.15, more preferably 1:99:0.1; the present invention preferably mixes the catalytic material, water, and polyethylene glycol, and ultrasonically disperses them uniformly to obtain the catalytic material dispersion. In the present invention, the coating is preferably spraying; the present invention preferably places the coating catalytic material dispersion in a spray gun, places the spray gun above the hydrophilic modified substrate loaded with microorganisms (the distance between the two is preferably 50 cm), and sprays the surface of the hydrophilic modified substrate loaded with microorganisms. After one round of spraying, it is dried with a blower dryer. The spraying and drying operations are repeated until the catalytic material loading meets the requirements to obtain the catalytic-microorganism coupling material.

[0053] This invention provides the application of the catalytic-microbial coupling material described in the above-described technical solutions, or the catalytic-microbial coupling material prepared by the preparation method described in the above-described technical solutions, in the preparation of electrocatalytic-microbial anodes. The catalytic-microbial coupling material of this invention can be used as an electrocatalytic-microbial anode in an electrocatalytic-microbial coupling device, and further used in the treatment of polluted water bodies and / or polluted sediments.

[0054] This invention provides an electrocatalytic-microbial coupling device, comprising a power supply device and a first cathode, a first anode, a second cathode, and a second anode arranged sequentially from top to bottom. The first cathode and the second cathode are connected to the negative electrode of the power supply device via wires, and the first anode and the second anode are connected to the positive electrode of the power supply device via wires. The first anode and the second anode are independently the catalytic-microbial coupling material described in the above technical solution or the catalytic-microbial coupling material prepared by the preparation method described in the above technical solution. The microorganisms loaded on the first anode are aerobic microorganisms, and the microorganisms loaded on the second anode are a mixture of electrogenic microorganisms and anaerobic microorganisms.

[0055] In this invention, the first cathode and the second cathode are preferably graphite plates. In this invention, the first anode is preferably the first coupling material; specifically, the doping amount of metal elements in the catalytic material on the first anode is preferably 0.1–0.18 wt%, more preferably 0.1–0.12 wt%; the microorganisms on the first anode are preferably aerobic microorganisms. In this invention, the second anode is preferably the second coupling material; specifically, the doping amount of metal elements in the catalytic material on the second anode is preferably 0.22–0.3 wt%, more preferably 0.28–0.3 wt%; the microorganisms on the second anode are preferably a mixture of electrogenic microorganisms and anaerobic microorganisms, wherein the mass ratio of electrogenic microorganisms to anaerobic microorganisms is preferably 1.5–2.5:1, more preferably 2:1.

[0056] In this invention, the first cathode, first anode, second cathode, and second anode are preferably placed sequentially on a four-layer frame from top to bottom. The spacing between adjacent layers in the four-layer frame is preferably 10-25 cm, more preferably 15-20 cm, and can be adjusted according to the river to be treated. This arrangement of the first cathode, first anode, second cathode, and second anode facilitates the coordination of voltage and current. The first anode has a lower metal doping content in its catalytic material, while the second anode has a higher metal doping content. In practical applications, when treating both polluted water and polluted sediment simultaneously, the polluted sediment typically has a higher pollutant content. Therefore, placing the second anode directly in contact with the polluted sediment and the first anode in contact with the polluted water further promotes microbial activation and organic matter degradation. Specifically, the principle of pollutant degradation by the electrocatalytic-microbial coupling device in this invention is as follows: In water, the upper layer is generally oxidized and the lower layer is reduced. After the electrocatalytic-microbial coupling device of this invention is placed in the water and put into operation, it will change the redox potential (ORP) in the water, promoting the exchange and transport between substances; at the same time, it will change the semi-reduced state of the mud-water interface to a semi-oxidized state, converting macromolecules into small molecules and improving bioavailability; moreover, under the action of a weak electric field, it will enhance the activity of microorganisms, promote their growth and reproduction, and facilitate the degradation of pollutants.

[0057] This invention provides the application of the catalytic-microbial coupling material described in the above technical solution, the catalytic-microbial coupling material prepared by the preparation method described in the above technical solution, or the electrocatalytic-microbial coupling device described in the above technical solution in the treatment of polluted water bodies and / or polluted sediment.

[0058] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0059] Preparation Example 1

[0060] Urea was placed in a crucible and then placed in a muffle furnace. It was calcined at 450°C for 2 hours in air to obtain graphitic carbon nitride (g-C3N4). 50g of the graphitic carbon nitride and an appropriate amount of ferric acetate were placed in a ball mill jar. Ethanol was added as a ball milling aid. The mixture was ball milled at 1000r / min for 10 minutes, then dried at 80°C, placed in a muffle furnace, and calcined at 450°C for 1 hour in air to obtain Fe2O3-doped graphitic carbon nitride (Fe2O3-g-C3N4). The Fe element doping amounts were 0.1wt% and 0.3wt%, respectively, and were designated as catalyst material #1 and catalyst material #2.

[0061] Preparation Example 2

[0062] Following the method of Preparation Example 1, except that ferric acetate was replaced with zinc acetate, ZnO-doped graphitic carbon nitride (ZnO-g-C3N4) was finally prepared, with Zn element doping amounts of 0.1 wt% and 0.3 wt%, respectively, and designated as catalyst material #3 and catalyst material #4.

[0063] Preparation Example 3

[0064] Following the method of Preparation Example 1, except that ferric acetate was replaced with nickel acetate, NiO-doped graphitic carbon nitride (NiO-g-C3N4) was finally prepared, with Ni element doping amounts of 0.1 wt% and 0.3 wt%, respectively, and designated as catalyst material #5 and catalyst material #6.

[0065] Test Example 1

[0066] Catalysts 1, 2, 3, 4, 5, and 6 were mixed with Rhodamine B solution and subjected to a dark reaction for 30 min. The absorbance of the 2.5 ppm Rhodamine B solution was measured. After the dark reaction, a light reaction was directly performed for 30 min (illumination at 60000 μw / cm²). 2 ), measure the absorbance of the Rhodamine B solution; calculate the removal efficiency of Rhodamine B according to Formula I:

[0067] Rhodamine B removal rate = (A1-A2) / A1×100% Equation I;

[0068] In Formula I, A1 is the absorbance of the Rhodamine B solution after the dark reaction, and A2 is the absorbance of the Rhodamine B solution after the light reaction.

[0069] Figure 1 The test diagram shows the removal effect of six catalytic materials on Rhodamine B in Test Example 1. The results show that catalytic materials 1, 2, 3, 4, 5 and 6 can effectively remove Rhodamine B, among which catalytic materials 3 and 4 have the best removal effect on Rhodamine B.

[0070] Example 1

[0071] The steps for preparing catalytic-aerobic microbial coupling materials are as follows:

[0072] Black sediment from the river channel (specifically, the southern section of the Ligang River in Jiangyin) was selected and initially screened to remove large particles. The initially screened sediment was then mixed with water at a mass ratio of 1:3 and acclimated at 25℃ for 7 days. After acclimation, 10 mL of the middle layer sediment-water mixture was taken, inoculated into sterile culture medium, and placed in an Erlenmeyer flask. The flask mouth was sealed with sterile tissue sealing film and sterilized at 25℃, pH 8.0±0.2, and rotation speed of 160 r / min. Enrichment cultures were conducted in an incubator for a total of four cycles. After each enrichment culture, the cells were centrifuged at 6000 rpm for 10 min, the supernatant was removed, and the precipitated cells were rinsed again with freshly prepared culture medium into an Erlenmeyer flask. The next enrichment culture was then conducted under the same conditions in a sterile incubator. The first enrichment culture lasted 15 days, and each subsequent enrichment culture lasted 25 days, yielding aerobic microorganisms (CFU of colonies formed per milliliter of sample was 4.12 × 10⁻⁶). 8 );

[0073] The activated carbon felt with a thickness of 1 cm was cleaned, dried, and then soaked in sulfuric acid (prepared by mixing 98 wt% concentrated sulfuric acid and water in a volume ratio of 1:1). It was modified at 25°C for 24 hours. After that, it was taken out and washed with distilled water to remove residual sulfuric acid. It was then dried in an oven at 60°C for 24 hours to obtain the hydrophilic modified substrate.

[0074] The aerobic microorganisms were mixed with the hydrophilic modified substrate and cultured at 25°C for 8 days. The mixture was then washed with distilled water to obtain the hydrophilic modified substrate loaded with aerobic microorganisms at a loading rate of 20 g / m³. 2Catalyst material #3 (from Preparation Example 2), distilled water, and polyethylene glycol were mixed in a mass ratio of 1:99:0.1 and ultrasonically dispersed to obtain a loading liquid. The loading liquid was poured into a spray gun, which was then placed 50 cm above the hydrophilic modified substrate loaded with aerobic microorganisms. The substrate was sprayed with the loading liquid, and after one round of spraying, it was dried with a blower. This spraying and drying process was repeated three times, with a total spraying volume of 500 mL / m³. 2 A catalytic-aerobic microbial coupling material was obtained.

[0075] Example 2

[0076] The steps for preparing the catalytic-electrogenic microorganism-anaerobic microorganism coupled material are as follows:

[0077] Black sediment from a river channel (specifically, the southern section of the Jiangyin Ligang River) was selected and subjected to initial screening to remove large particles. The sludge was then mixed with liquid culture medium at a volume ratio of 1:5 to obtain wastewater. A bipolar chamber microbial fuel cell (MFC) was used, with two equal-volume glass bottles pre-sterilized by autoclaving. A titanium plate was used as the anode, and the entire anode was immersed in the wastewater. Electrogenic microorganisms would adhere to the anode surface, and the anode chamber was kept sealed to prevent air from entering. An unpolished high-purity graphite electrode was used as the cathode, and the cathode chamber contained... A 0.2 mol / L phosphate buffer solution was added to maintain the pH of the reaction tank at 6.8–7.2, increase the conductivity of the solution, and reduce the internal resistance of the battery. An aeration head was installed at the bottom of the cathode to provide oxygen and mix the components. The electrodes were connected to a load resistor via a copper wire. The load resistor was an adjustable resistance box, and a digital multimeter was connected across the load resistor (resistance stabilized at 500 Ω) to monitor and record changes in the external circuit voltage online. Electrogenic microorganisms attached to the anode surface were collected (the number of colony-forming units (CFU) per milliliter of sample was 1.45 × 10⁻⁶). 8 );

[0078] Black sediment from the river channel (specifically, the southern section of the Ligang River in Jiangyin) was selected and initially screened to remove large particles. The sieved sediment was then mixed with liquid culture medium at a volume ratio of 1:5 and placed in an Erlenmeyer flask. The upper part of the flask was purged with argon gas to remove air. Enrichment culture was performed four times in a sterile incubator at 30℃ and pH 7.2±0.2, with continuous stirring at 120 rpm for 10 hours every 6 hours during the enrichment process. After each enrichment culture, the sample was centrifuged at 6000 rpm for 10 minutes, the supernatant was removed, and the precipitated bacteria were rinsed again with freshly prepared culture medium in the Erlenmeyer flask. The next enrichment culture was then performed under the same conditions in a sterile incubator. The first enrichment culture lasted 15 days, and subsequent enrichment cultures lasted 23 days each, yielding anaerobic microorganisms (CFU of colonies formed per milliliter of sample was 2.74 × 10⁻⁶). 8 );

[0079] The electrogenic microorganisms and anaerobic microorganisms were mixed at a mass ratio of 2:1 to obtain a mixed microorganism. The mixed microorganisms were then mixed with a hydrophilic modified substrate (prepared according to the method in Example 1) and cultured at 25°C for 8 days. Afterward, the substrate was washed with distilled water to obtain a hydrophilic modified substrate loaded with the mixed microorganisms, wherein the loading amount of the mixed microorganisms was 20 g / m³. 2 The catalytic material #4 (from Preparation Example 2), distilled water, and polyethylene glycol were mixed in a mass ratio of 1:99:0.1 and ultrasonically dispersed to obtain a loading liquid. The loading liquid was poured into a spray gun, which was then placed 50 cm above the hydrophilic modified substrate loaded with the mixed microorganisms. The mixture was sprayed onto the surface of the substrate, and after one pass, it was dried using a blower. This spraying and drying process was repeated three times, with a total spray volume of 500 mL / m³. 2 A coupled material of catalytic-electrogenic microorganism-anaerobic microorganism was obtained.

[0080] Example 3

[0081] The catalytic-aerobic microbial coupling material prepared in Example 1 was used as the first anode, and the catalytic-electrogenic microbial-anaerobic microbial coupling material prepared in Example 2 was used as the second anode. Graphite plates were used as the first and second cathodes. The first cathode, first anode, second cathode, and second anode were placed sequentially on a four-layer frame from top to bottom. The spacing between adjacent layers in the four-layer frame was 20 cm. The first cathode and second cathode were connected to the negative electrode of the power supply equipment, and the first anode and second anode were connected to the positive electrode of the power supply equipment to obtain the electrocatalytic-microbial coupling device, which is denoted as coupling device #2.

[0082] Example 4

[0083] Referring to Examples 1 and 2, a first anode and a second anode were prepared using catalytic material 1 and catalytic material 2 (from Preparation Example 1), respectively. Then, an electrocatalytic-microbial coupling device was assembled according to Example 3, which is referred to as coupling device 1.

[0084] Example 5

[0085] Referring to Examples 1 and 2, the first anode and the second anode were prepared using catalytic material #5 and catalytic material #6 (from Preparation Example 3), respectively. Then, an electrocatalytic-microbial coupling device was assembled according to Example 3, which is referred to as coupling device #3.

[0086] Comparative Example 1

[0087] Referring to Examples 1 and 2, a first anode and a second anode were prepared using catalytic material #3 and catalytic material #4 (from Preparation Example 2), respectively. The difference is that the first anode does not carry aerobic microorganisms and the second anode does not carry electrogenic microorganisms or anaerobic microorganisms. Then, an electrocatalytic device was assembled according to Example 3, which is referred to as Electrocatalytic Device #4.

[0088] Test Example 2

[0089] Take nine 1000mL beakers, add black sediment from the riverbed (specifically, the southern section of the Jiangyin Ligang River) to the bottom, and perform initial screening to remove large particles. Add prepared simulated wastewater (main components include glucose, potassium dihydrogen phosphate, ammonium chloride, etc.), with a sediment-to-wastewater volume ratio of 1:8. Add coupling devices #1, #2, and #3 to the beakers respectively. Figure 2 (For experimental schematic diagram), 3 sets of parallel samples were set up, the power was turned on, the voltage was set to 1V, and the simulated wastewater was treated.

[0090] Figure 3 The figure shows the COD removal rate test results of each coupling device used in Test Example 2. The results show that the overall COD showed a downward trend, the removal rate continued to increase, and it reached a basic stability after 10 days. The COD removal rates of coupling devices 1, 2 and 3 were 82.08%, 88.22% and 78.21%, respectively.

[0091] Figure 4 The graph shows the ammonia nitrogen removal rate test results of each coupling device used in Test Example 2. The results show that the ammonia nitrogen generally showed a downward trend, and the removal rate continued to increase. After 10 days, it reached a basic stability. The ammonia nitrogen removal rates of coupling devices 1, 2 and 3 were 75.96%, 81.39% and 71.88%, respectively.

[0092] Figure 5The graph shows the organic matter removal rate test results of each coupling device used in Test Example 2. The results show that the organic matter generally showed a downward trend, the removal rate continued to increase, and reached a basic stability after 15 days. The organic matter removal rates of coupling devices 1, 2 and 3 were 76.3%, 78.93% and 71.05%, respectively.

[0093] After the water quality and removal rate of the devices stabilized, the microorganisms on the anodes of coupling devices 1, 2, and 3 were tested, and the results are shown in Table 1. The results showed that coupling device 2 had higher levels of VSS / TSS, TTC dehydrogenase, protein, and polysaccharide, higher biomass, and better biological activity, followed by coupling device 1, and coupling device 3 had the lowest levels.

[0094] Table 1. Microbial test results on electrodes in coupling devices #1, #2, and #3

[0095]

[0096] Test Example 3

[0097] The performance of coupling device #2 and electrocatalytic device #4 was tested according to the method in test example 2.

[0098] Figure 6 The figure shows the COD removal rate test results of the No. 2 coupling device and the No. 4 electrocatalytic device in Test Example 3. The results show that the COD removal rate in the water is higher when the No. 2 coupling device is used.

[0099] Figure 7 The graph shows the ammonia nitrogen removal rate test results of the No. 2 coupling device and the No. 4 electrocatalytic device in Test Example 3. The results show that the ammonia nitrogen removal rate in the water is higher when the No. 2 coupling device is used.

[0100] Test Example 4

[0101] The No. 2 coupling device was placed in the southern section of the Jiangyin Ligang River and connected to the power supply to treat the water.

[0102] Figure 8 The figure shows the current test results when the No. 2 coupling device was used to treat the southern section of the Ligang River in Jiangyin in Test Example 4. The results show that the current corresponding to 1V voltage is about 7μA.

[0103] Figure 9 The figure shows the COD removal rate test results when the No. 2 coupling device was used to treat the southern section of the Ligang River in Jiangyin in Test Example 4. The results show that as the No. 2 coupling device was put into the river, the COD value decreased significantly and reached a basic stability after 25 days. The COD removal rate was about 83%, and the water quality improved from Class IV to near Class I.

[0104] Figure 10The figure shows the test results of ammonia nitrogen removal rate when the No. 2 coupling device was used to treat the southern section of the Ligang River in Jiangyin in Test Example 4. The results show that as the No. 2 coupling device was put into the river, the ammonia nitrogen value decreased significantly and reached a basic stability after 25 days, with an ammonia nitrogen removal rate of about 68%.

[0105] Figure 11 The figure shows the test results of the organic matter removal rate in the bottom sediment when the No. 2 coupling device was used to treat the southern section of the Jiangyin Ligang River in Test Example 4. The results show that as the No. 2 coupling device was put into the river, the organic matter content in the bottom sediment decreased significantly and reached a basic stability after 30 days, with an organic matter removal rate of about 74%.

[0106] Figure 12 The image shows a comparison of the water quality before and after the treatment of the Jiangyin Ligang South Section River using the No. 2 coupling device in Test Example 4. The results show that after the treatment of the Jiangyin Ligang South Section River using the No. 2 coupling device, the water transparency was significantly improved, in-situ aquatic plants grew and reproduced, and the coverage of aquatic plants increased and they grew well.

[0107] During the treatment of the southern section of the Jiangyin Ligang River using the No. 2 coupling device, the biodiversity index in the bottom sediment was measured, and the results are shown in Table 2. The ACE, Chao, and Shannon biodiversity indices in the bottom sediment indicate that, compared to the original state, the microbial diversity in the water body has decreased, with microorganisms increasingly enriching in the dominant functional bacterial groups.

[0108] Table 2 Results of biodiversity index detection in bottom sediment

[0109] Detection time OTU ACE Chao shannon initial 6325 6494.6 6352.1 7.2 30d 5124 5254.9 5044.9 6.1 37d 4613 4825.4 4616.2 6.8 44d 5468 5581.9 5362.3 7.0

[0110] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An electro-catalysis-microorganism coupling device, characterized in that, The device comprises a power supply device and first and second cathodes and first and second anodes arranged in sequence from top to bottom, the first and second cathodes being connected to the negative pole of the power supply device by wires, and the first and second anodes being connected to the positive pole of the power supply device by wires; The first and second anodes are independently catalytic-microbial coupling materials, the catalytic-microbial coupling material comprising a hydrophilic modified substrate and microorganisms and catalytic materials loaded on the hydrophilic modified substrate, the microorganisms being a mixture of electrogenic microorganisms and anaerobic microorganisms, or the microorganisms being aerobic microorganisms; and the catalytic material being graphite phase carbon nitride doped with metal oxides; The hydrophilic modified substrate is obtained by modifying activated carbon felt with an acid reagent, the steps being as follows: sequentially washing and drying the activated carbon felt, then soaking in an acid reagent for modification, taking out the modified activated carbon felt and sequentially washing and drying to obtain the hydrophilic modified substrate; The metal oxide is ZnO, the doping amount of metal elements in the catalytic material is 0.1-0.3wt%; the loading amount of the catalytic material in the catalytic-microbial coupling material is 2-5g / m 2 ; The microorganisms loaded on the first anode are aerobic microorganisms, and the microorganisms loaded on the second anode are a mixture of electrogenic microorganisms and anaerobic microorganisms.

2. The electro-catalysis-microorganism coupling device according to claim 1, characterized in that, The thickness of the activated carbon felt is 1-3 cm; the modification temperature is 25-28℃, and the time is 20-28 h.

3. The electro-catalysis-microorganism coupling device according to claim 1, wherein, The loading amount of the microorganism on the catalysis-microorganism coupling material is 20-25 g / m 2 The mass ratio of the electrogenic microorganism to the anaerobic microorganism in the mixture of the electrogenic microorganism and the anaerobic microorganism is 1.5-2.5:

1.

4. The electro-catalysis-microorganism coupling device according to claim 1, wherein, The preparation method of the catalytic-microbial coupling material comprises the following steps: Mixing the microorganisms with the hydrophilic modified substrate for culture to obtain the hydrophilic modified substrate loaded with microorganisms; Coating a catalytic material dispersion liquid on the surface of the hydrophilic modified substrate loaded with microorganisms, and drying to obtain the catalytic-microbial coupling material.

5. The electro-catalysis-microorganism coupled device according to claim 1, wherein, The first and second cathodes are graphite plates; the doping amount of metal elements in the catalytic material on the first anode is 0.1-0.18wt%; and the doping amount of metal elements in the catalytic material on the second anode is 0.22-0.3wt%.

6. The application of the electro-catalytic-microbial coupling device of any one of claims 1-5 in the treatment of contaminated water bodies and / or contaminated sediments.

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