Apparatus and method for controlling internal phosphorus release in water bodies based on electron transfer

Abstract

This invention discloses a device and method for controlling the release of endogenous phosphorus in water based on electron transfer. The device includes: a carbon-based electronic conductor, a current collector, a support frame, and a cover plate; the support frame is a hollow structure with openings at both ends; the cover plate is fixed to one end of the support frame, and the other end of the support frame is used to insert into water sediment for fixation; the cover plate has a central hole, one end of the carbon-based electronic conductor is fixed to the cover plate, and the other end passes through the central hole and is suspended inside the hollow structure; the current collector is disposed inside the hollow structure of the support frame and surrounds the carbon-based electronic conductor. This invention utilizes conductive materials as a medium, which can shorten the electron transfer distance, reduce electrode costs, and efficiently control endogenous phosphorus in water; it has the characteristics of simple operation, low investment cost, and high efficiency, and can also simultaneously achieve organic pollution removal and endogenous phosphorus fixation, and the organic pollution removal process can be monitored.

Description

Technical Field

[0001] This invention relates to the field of aquatic microbial remediation technology, and to a device and method for controlling the release of endogenous phosphorus in water, specifically to a device and method for controlling the release of endogenous phosphorus in water based on electron transfer. Background Technology

[0002] Eutrophication poses a serious threat to drinking water safety and the sustainability of aquatic ecosystems. Phosphorus is the most important factor in controlling eutrophication, accounting for approximately 80% of all eutrophication cases. The main causes of excessive phosphorus in water bodies include the influx of phosphorus from external sources and the release of phosphorus from within the water body itself. External phosphorus influx includes excessive application of superphosphate fertilizers and the discharge of large amounts of phosphorus-containing wastewater. Internal phosphorus release primarily occurs from sediments, which is also a significant source of pollution in lakes and causes of eutrophication. Therefore, the main approach to controlling eutrophication caused by excessive phosphorus in water bodies due to internal phosphorus release is to minimize the release of phosphorus from sediments. However, due to the complexity of sediments and the diverse forms in which phosphorus exists within them, controlling the release of phosphorus from within water bodies remains a challenging problem.

[0003] The release of endogenous phosphorus from sediments is primarily due to the dissolution of iron-bound phosphorus. Oxygen can act as an electron acceptor for microbial respiration in surface sediments, thereby guiding phosphorus immobilization through the formation of Fe2(PO4)3 precipitates or adsorption by Fe(OH)3. However, the introduction of pollutants and hydrothermal stratification caused by prolonged high temperatures and sunlight in summer lead to a reduction in dissolved oxygen in the bottom water. Fe(III) is reduced to Fe(II), thereby decreasing the sediment's ability to fix phosphorus, resulting in the release of phosphorus from the sediments.

[0004] Excessive phosphorus levels in lakes can easily lead to eutrophication, which in turn causes algal blooms (such as cyanobacteria) and threatens aquatic biodiversity. Current methods for addressing algal blooms caused by eutrophication mainly include dredging, cyanobacteria harvesting, and the addition of adsorbents. For example, dredging can remove some nitrogen and phosphorus from sediments, reducing the nitrogen and phosphorus content in the water, effectively mitigating algal blooms, and thus improving lake water quality. Another example is adding adsorbents to the surface of the remediation body: CN106045248A discloses a method for enhancing the fixation of endogenous phosphorus in eutrophic water body sediment. The steps of this method are as follows: First, filter the sludge from the water treatment plant through an iron screen, dry it, then crush it and pass it through a 100-mesh sieve; Second, mix anhydrous calcium chloride powder (passed through a 100-mesh sieve) into the treated sludge from the water treatment plant, and mix them evenly to obtain a mixed material; Third, calcine the mixed material to obtain an endogenous phosphorus solidification material; Fourth, spread the endogenous phosphorus solidification material evenly on the surface of the eutrophic water body sediment to be remediated; Fifth, introduce river clams; Sixth, after 10 days, spread the endogenous phosphorus solidification material evenly again on the surface of the eutrophic water body sediment to be remediated, thus completing the steps of enhancing the fixation of endogenous phosphorus in the eutrophic water body sediment. This method can change the internal microenvironment of the sediment and form a space and state where anaerobic and aerobic alternate, enhancing the interconversion between endogenous phosphorus forms.

[0005] However, these methods are all traditional physical, chemical, or biological remediation methods, and they all face difficulties such as non-in-situ treatment, high costs, and significant water body disturbance. Moreover, they often result in incomplete remediation.

[0006] Furthermore, bioelectrochemical systems (BESs) have emerged for sediment remediation. Existing sediment bioelectrochemical systems work by burying the anode in anoxic sediments to act as an electron acceptor, capturing electrons and transferring them to an aerobic cathode via connecting wires. This significantly inhibits the reduction of available Fe(III) and reduces phosphorus release. For example, Chinese patent document CN 101962232B discloses a sediment bioelectrochemical device and its application. The device mainly consists of a cathode, anode, wires, a resistor, and a stirring shaft with spiral blades, a support rod, and a scraper. The cathode in the aqueous phase, the anode in the sediment, and the resistor are connected in series via wires to form a circuit, with the resistor positioned between the cathode and anode. However, the introduction of the anode and cathode in this existing bioelectrochemical system increases the cost of electrode installation and results in significant electron transfer resistance and low electron transfer efficiency.

[0007] Therefore, there is an urgent need to develop a device and method that has low electrode input costs and high electron transfer efficiency, and can efficiently control endogenous phosphorus in water. Summary of the Invention

[0008] The technical problem to be solved by this invention is to provide a device and method for controlling the release of endogenous phosphorus in water based on electron transfer. Its purpose is to address the shortcomings of existing technologies by using conductive materials as a medium to shorten the electron transfer distance, reduce electrode costs, and efficiently control the release of endogenous phosphorus in water.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a device for controlling the release of endogenous phosphorus in water based on electron transfer, comprising: a carbon-based electronic conductor, a current collector, a support frame, and a cover plate;

[0011] The supporting frame is a hollow structure with openings at both ends;

[0012] The cover plate is fixed to one end of the support frame, and the other end of the support frame is used to be inserted into the water sediment for fixation; the cover plate has a central hole, one end of the carbon-based electronic conductor is fixed to the cover plate, and the other end passes through the central hole and is suspended in the hollow structure;

[0013] The current collector is disposed within the hollow structure of the supporting frame and surrounds the carbon-based electronic conductor.

[0014] Furthermore, the supporting frame is generally configured as a hollow cylinder with openings at both ends. In actual repair applications, the processing capacity is measured by its repair radius.

[0015] Furthermore, there are several ways to fix one end of the carbon-based electronic conductor to the cover plate:

[0016] In one embodiment, the cover plate has several grooves along the axial direction of the cover plate with the central hole as the center on the side facing away from the water. The end of the carbon-based electronic conductor exposed on the cover plate has several screws with a number corresponding to the grooves along its axial direction with the carbon-based electronic conductor as the center. The size of the screws matches the grooves, and one end of the screws is fixed to the carbon-based electronic conductor. Each groove on the cover plate has a matching fastener above it, and one end of the carbon-based electronic conductor is fixed to the cover plate by the fastener.

[0017] Furthermore, in various embodiments of the present invention, there are multiple ways to connect one end of the support frame to the cover plate:

[0018] In one embodiment, the cover plate has an annular groove on the side facing the water, and the hollow cylinder matches the annular groove to achieve a fixed connection between one end of the support frame and the cover plate.

[0019] In another embodiment, the edge of the cover plate has an extension edge facing the side connected to the support frame, and the outer wall of the support frame is interference-fitted with the inner wall of the extension edge to achieve a fixed connection between one end of the support frame and the cover plate.

[0020] Furthermore,

[0021] To facilitate sampling during water remediation and to ensure unobstructed airflow and oxygen diffusion between the water and sediment and the outside air, the cover plate is provided with several sampling and air intake slits. Preferably, the sampling and air intake slits are annular slits or fan-shaped annular slits.

[0022] Furthermore,

[0023] The carbon-based electronic conductor is made of carbon material with good electron transport function and is generally cylindrical.

[0024] Furthermore,

[0025] The collector plate is a stainless steel wire mesh made of stainless steel wire. Using stainless steel is more economical and practical.

[0026] Furthermore,

[0027] The hollow structure supporting the framework has several through holes on its outer wall to facilitate mass transfer and electron transport in the surrounding water.

[0028] Furthermore,

[0029] The device also includes an electrical signal acquisition unit, the cathode of which is connected to a current collector and the anode of which is connected to a carbon-based electronic conductor. The electrical signal acquisition unit reads the electrical signal between the current collector and the carbon-based electronic conductor to assess the progress of water body restoration.

[0030] Preferably, the electrical signal acquisition device is a multimeter, and the electrical signal read is voltage. The electrical signal is read at preset intervals to assess the progress of water body restoration.

[0031] Furthermore,

[0032] The cover plate is also provided with Fe(III) addition holes. The Fe(III) addition holes are used to add Fe(III) into the water to enrich the endogenous phosphorus fixation forms and improve the control efficiency of endogenous phosphorus release.

[0033] The added Fe(III) is a soluble trivalent iron salt, such as ferric sulfate, ferric chloride, ferric nitrate, etc.

[0034] In practical applications, the length of the support frame is designed according to the depth of the specific water body being treated.

[0035] Secondly, the present invention provides a method for controlling the release of endogenous phosphorus in water using the above-mentioned device, specifically comprising the following steps:

[0036] S1. Insert the end of the support frame away from the cover plate into the water sediment, extend one end of the carbon-based electronic conductor into the water of the hollow structure of the support frame, and surround the carbon-based electronic conductor with a mesh plate to form the current collector.

[0037] S2. Fix the other end of the carbon-based electronic conductor to the other end of the support frame by means of the cover plate, so that the carbon-based electronic conductor is suspended in the water body of the hollow structure of the support frame.

[0038] S3. Use an electrical signal acquisition device to record the open-circuit voltage between the current collector and the carbon-based electronic conductor to monitor the phosphorus fixation and remediation process.

[0039] Furthermore, the method also includes adding Fe(III) into the water body supporting the hollow structure of the skeleton through the Fe(III) addition hole on the cover plate.

[0040] Preferably, the mass percentage of Fe(III) added relative to the weight of the water in the hollow structure is x, where 0 < x ≤ 5%. More preferably, x is 0.5%. The weight of the water in the hollow structure supporting the skeleton is calculated based on the radius of the hollow structure (cylinder).

[0041] Furthermore, the method includes setting up several devices for controlling the release of endogenous phosphorus from the treated water area.

[0042] Applying the above-mentioned device to water pollution remediation can improve the removal rate of total organic carbon (TOC) in polluted water and reduce the release of endogenous phosphorus from polluted water.

[0043] The present invention has the following beneficial effects:

[0044] This invention provides a device and method for controlling the release of endogenous phosphorus in water based on electron transfer. Utilizing conductive materials as a medium, it shortens the electron transfer distance, reduces electrode costs, and efficiently controls endogenous phosphorus in water. Compared with existing technologies, it has the following advantages:

[0045] 1. High electron transfer efficiency. This invention utilizes a carbon-based electronic conductor to provide an abundant electron acceptor interface for microbial metabolism. The carbon-based electronic conductor, placed inside polluted water, collects electrons generated by microbial metabolism and transfers them to the oxygen-rich water surface using its excellent conductivity, thus solving the polarization loss during electron transfer. Electrons do not need to undergo a lengthy transfer process: organic matter-microorganism-(shuttle)-anode-wire-cathode-oxygen. Therefore, the electron transfer rate is significantly improved.

[0046] 2. Efficiently achieves endogenous phosphorus fixation. The efficient electron transfer of the carbon-based electronic conductor in this invention provides a superior electron acceptor (conductor and O2) for electrons generated by microbial metabolism in sediments. The increased electron exit pathway replaces the reduction process of iron in sediments / interstitial water, making the phosphorus fixation products in the water more stable, thereby reducing the release of phosphorus from sediments and interstitial water into the overlying water.

[0047] 3. Simultaneous removal of organic pollutants and phosphorus fixation, with the organic pollutant removal process monitorable. When using the device of this invention for water treatment, indigenous microorganisms in the water can accumulate in the carbon-based electronic conductor. The ectopic and efficient combination of the microbial oxidation half-reaction and the oxygen reduction half-reaction in the overlying water can effectively promote the removal of organic pollutants. In addition, the open-circuit voltage between the current collector and the carbon-based electronic conductor can be read by an electrical signal acquisition device (e.g., a multimeter). By analyzing the changes in the open-circuit voltage between the current collector and the carbon-based electronic conductor, the concentration of organic pollutants in the polluted water can be monitored.

[0048] 4. Low investment cost and simple operation. Compared with traditional methods, this invention simplifies the anode deposition filling and cathode water floating setting to a carbon-based electronic conductor, which can reduce the cost of wires and anodes.

[0049] Furthermore, the operation is even simpler after the setup is completed; water remediation and phosphorus fixation can be performed simply by fixing the carbon-based electronic conductor and hanging it vertically in the water container. Attached Figure Description

[0050] Figure 1 A schematic diagram of the device for controlling the release of endogenous phosphorus in water based on electron transfer, provided in an embodiment of the present invention.

[0051] Figure 2 This is a graph showing the change in electrical signals during the water body restoration process according to an embodiment of the present invention.

[0052] Figure 3 This is a comparison chart of TOC changes in water bodies between embodiments and comparative examples of the present invention.

[0053] Figure 4 This is a comparison diagram of TP changes in water bodies between embodiments and comparative examples of the present invention.

[0054] Figure descriptions: 1. Carbon-based electronic conductor; 2. Current collector; 3. Cover plate; 301. Center hole; 302. Sampling and air inlet pre-reserved slot; 4. Support frame; 5. Screw; 6. Fixture. Detailed Implementation

[0055] The technical solutions in the embodiments of the present invention will be further explained below with reference to the accompanying drawings. 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.

[0056] Example 1:

[0057] See Figure 1 This invention provides a device for controlling the release of endogenous phosphorus in water based on electron transfer, comprising: a carbon-based electronic conductor 1, a current collector 2, a supporting frame 4, and a cover plate 3. Specifically,

[0058] As a preferred embodiment, the support frame 4 is a hollow structure with openings at both ends, specifically a hollow cylindrical structure with openings at both ends. Its processing capacity during actual repair is based on its repair radius. The cover plate 3 is fixed to one end of the support frame 4, and the other end of the support frame 4 is used for insertion into the water sediment for fixation. The cover plate 3 has a central hole 301. One end of the carbon-based electronic conductor 1 is fixed to the cover plate 3, and the other end passes through the central hole 301 and is suspended inside the hollow structure. In practical applications, after the support frame 4 is inserted and fixed in the water sediment, the length of the carbon-based electronic conductor 1 should still be sufficient, with its bottom end suspended inside the hollow structure.

[0059] The current collector 2 is installed inside the hollow structure of the supporting frame 4. Figure 1 (Represented by dashed lines) and arranged around the carbon-based electronic conductor 1. The current collector 2 in this invention is mainly used to form an open circuit with the carbon-based electronic conductor 1, and to collect the open circuit voltage through an electrical signal acquisition device to monitor the concentration changes of organic pollutants in polluted water.

[0060] There are multiple ways to fix one end of the carbon-based electronic conductor 1 to the cover plate 3. The connection method in this embodiment is as follows: On the side of the cover plate 3 facing away from the water, there are several grooves (not shown in the figure) centered on the central hole 301 along the axial direction of the cover plate 3; On the end of the carbon-based electronic conductor 1 exposed on the cover plate 3, there are several screws 5 of the same number as the grooves centered on the carbon-based electronic conductor 1 along its axial direction. The size of the screws 5 matches the grooves. One end of the screws 5 is fixed on the carbon-based electronic conductor 1. Each groove on the cover plate 3 is provided with a matching fastener 6. The fastener 6 fixes one end of the carbon-based electronic conductor 1 to the cover plate 3.

[0061] There are multiple ways to connect one end of the support frame 4 to the cover plate 3. In this embodiment, the connection method is as follows: the edge of the cover plate 3 facing the side connected to the support frame 4 is provided with an extension edge. The outer wall of the support frame 4 and the inner wall of the extension edge are interference-fitted to achieve a fixed connection between one end of the support frame 4 and the cover plate 3.

[0062] To facilitate sampling during the water remediation process and to maintain unobstructed airflow and oxygen diffusion between the water and sediment and the outside air, the cover plate 3 is provided with several sampling and air intake slits 302. In this embodiment, the sampling and air intake slits 302 are fan-shaped annular slits.

[0063] The carbon-based electronic conductor 1 is made of carbon material with good electron transport properties and is generally cylindrical. The device also includes an electrical signal acquisition unit (not shown in the figure). The cathode of the electrical signal acquisition unit is connected to the current collector 2 via a wire, and its anode is connected to the carbon-based electronic conductor 1 via a wire. The electrical signal acquisition unit reads the electrical signal between the current collector 2 and the carbon-based electronic conductor 1 to assess the progress of water body remediation. In this embodiment, a multimeter is used as the electrical signal acquisition unit, and the read electrical signal is voltage. The electrical signal is read at preset intervals. By analyzing the change in the open-circuit voltage between the current collector 2 and the carbon-based electronic conductor 1, the concentration of organic pollutants in the polluted water can be monitored.

[0064] In this embodiment, the flow collector 2 is a stainless steel wire mesh made of stainless steel wire, which is more economical and practical. To facilitate mass transfer and electron transfer in the surrounding water, several through holes are provided on the outer wall of the hollow structure of the supporting frame 4. To enrich the fixation forms of endogenous phosphorus and improve the control efficiency of endogenous phosphorus release, the cover plate is also provided with Fe(III) addition holes (not shown in the figure). Those skilled in the art will understand that any structure on the cover plate that can be used to add Fe(III) can be considered as a Fe(III) addition hole, including Fe(III) addition holes set separately on the cover plate, or Fe(III) added through the sampling and air inlet pre-reserved slit or central hole. The Fe(III) addition holes are used to add Fe(III) to the water. In specific implementation, the length of the supporting frame 4 is designed according to the depth of the specific water body being treated. The added Fe(III) is a soluble trivalent iron salt, such as ferric sulfate, ferric chloride, ferric nitrate, etc. The mass percentage of Fe(Ⅲ) added relative to the weight of the water in the hollow structure is x, where 0 < x ≤ 5%. The following examples use 0.5% as an example.

[0065] The method for controlling the release of endogenous phosphorus in water using the above-mentioned device specifically includes the following steps:

[0066] S1. Insert the end of the support frame 4 away from the cover plate 3 into the water sediment, extend one end of the carbon-based electronic conductor 1 into the water of the hollow structure of the support frame 4, and surround the carbon-based electronic conductor 1 with a mesh plate to form the current collector 2.

[0067] S2. The other end of the carbon-based electronic conductor 1 is fixed to the other end of the support frame 4 through the cover plate 3, so that the carbon-based electronic conductor 1 is suspended in the water body of the hollow structure of the support frame 4; in order to enrich the endogenous phosphorus fixation form and improve the control efficiency of endogenous phosphorus release, Fe(III) is added to the water body of the hollow structure of the support frame through the Fe(III) addition hole on the cover plate 3.

[0068] S3. Use an electrical signal acquisition device to record the open-circuit voltage between the current collector 3 and the carbon-based electronic conductor 1 to monitor the phosphorus fixation and remediation process.

[0069] For large areas of water that need to be treated, the method includes installing several devices in the treated water area to control the release of endogenous phosphorus from the water.

[0070] Application Examples

[0071] To verify the feasibility and effectiveness of the device and method of the present invention, the device for controlling the release of endogenous phosphorus in water provided in the embodiments was designed as a small-scale experimental device to simulate the environment for the release of endogenous phosphorus in water, and the release of endogenous phosphorus in water was controlled by this device. Details are as follows:

[0072] I. Design and Construction of the Device

[0073] The support frame of the structure device shown in Example 1 is used to insert one end of the opening into the sediment of the water body and is sealed by the bottom cover, so that the hollow structure of the support frame forms a container that can hold water. The overlying water and silt to be repaired are poured into the container to simulate the environment of endogenous phosphorus release in the water body.

[0074] The specific structure and dimensions of the device are as follows:

[0075] The diameter of the carbon-based electronic conductor 1 is 1-50 mm; in this embodiment, the diameter of the carbon-based electronic conductor 1 is set to 10 mm. The distance between the current collector 2 and the carbon-based electronic conductor 1 is 10-200 mm; in this embodiment, it is set to 60 mm. The diameter of the stainless steel wire forming the current collector 2 is 0.1-5 mm; in this embodiment, it is set to 0.5 mm. The aperture of the stainless steel wire mesh is 0.2-10 mm; in this embodiment, it is set to 2.5 mm. The diameter of the formed container (the hollow structure supporting the skeleton) is 20-200 mm; in this embodiment, it is set to 120 mm. The depth is 40-300 mm; in this embodiment, it is set to 150 mm.

[0076] One end of the carbon-based electronic conductor is fixed, and the other end is suspended 0-50 mm from the bottom of the container (10 mm in this embodiment); the carbon-based electronic conductor is placed in the center of the container. Approximately 1.2 L of phosphorus-rich overlying water and silt are poured into the water container.

[0077] II. Equipment Operation and Polluted Water Remediation

[0078] During the operation of the device, the reaction temperature is maintained at room temperature (25℃). The progress of water remediation is assessed by reading the voltage signal between the current collector 2 and the carbon-based electronic conductor 1 using a multimeter. The cathode of the multimeter is connected to the current collector, and its anode is connected to the carbon-based electronic conductor. The experiment is stopped after the voltage finally stabilizes.

[0079] The experiment was designed with the following four treatment groups, as shown in Table 1:

[0080] Table 1. Settings for each processing group

[0081] Group Specific processing settings mark Comparative Example 1 Phosphorus-rich water bodies without carbon-based electronic conductors and current collectors and with 0% iron addition. OC Comparative Example 2 Phosphorus-rich water bodies without carbon-based electronic conductors and current collectors, and with an iron dosage of 0.5%. OC-0.5 Example 1 Phosphorus-rich water bodies equipped with carbon-based electronic conductors and current collectors, and with 0% iron addition. CC Example 2 Phosphorus-rich water bodies equipped with carbon-based electronic conductors and current collectors, and with an iron dosage of 0.5%. CC-0.5

[0082] The following tests were conducted on the above groups respectively:

[0083] 1. Monitor the voltage output during phosphorus fixation and remediation processes in each treatment group.

[0084] Since Comparative Examples 1 and 2 do not contain carbon-based electronic conductors and current collectors, these two control treatment groups have no electrical signal output. The voltage output during the water phosphorus fixation and remediation processes corresponding to Examples 1 and 2 is as follows: Figure 2 As shown.

[0085] Depend on Figure 2 It can be known that:

[0086] During the first two days of operation, the voltage output showed a decreasing trend, decreasing from 0.13V to 0V, indicating a capacitor discharge process in the water body to be repaired. From day 2 to 14, the voltages in Examples 1 and 2 were negligible, indicating gradual enrichment of the microbial carbon-based electronic conductor surface. After this period, the voltage output gradually increased, reaching 0.21V (Example 1) and 0.19V (Example 2) on day 17, and then peaking on day 33, at 0.29V for Example 1 and 0.26V for Example 2. Subsequently, the voltage showed a slow decreasing trend, dropping to ~70mV on day 84, indicating that the organic matter had been decomposed by the microorganisms during the operation. This demonstrates that the carbon-based electronic conductor 1 acts as an electron acceptor during the organic matter decomposition process, and the addition of Fe(III) (Example 2) competes with the electrode for electrons, resulting in a slight decrease in open-circuit voltage.

[0087] 2. Removal rate of organic pollutants during water remediation in each treatment group

[0088] In this test, the removal of organic pollutants during the remediation process is expressed as total organic carbon (TOC), and the results are as follows: Figure 3 As shown.

[0089] Depend on Figure 3 It can be known that:

[0090] In all cases, TOC decreased. However, the TOC removal rates of Examples 1 and 2 were 94% and 97%, respectively, higher than the 91% of Comparative Examples 1 and 2, indicating that the introduction of carbon-based electronic conductor 1 can improve the removal efficiency of organic pollutants in water. Example 2 had the highest TOC removal rate, indicating that the introduction of carbon-based electronic conductor, together with Fe(III), can act as an alternative electron acceptor to accelerate electron transfer, thereby accelerating the degradation process of organic matter. Furthermore, it is easy to see that the TOC removal rate of Example 1 is higher than that of Comparative Example 2, indicating that a single carbon-based electronic conductor is superior to a single Fe(III) oxide as an electron acceptor for organic biodegradation.

[0091] 3. Monitor changes in total phosphorus (TP) in the overlying water during phosphorus fixation and remediation processes in each treatment group.

[0092] This test monitored the changes in total phosphorus (TP) in the overlying water of the treatment group during phosphorus fixation and water remediation. The results are as follows: Figure 4 As shown.

[0093] Depend on Figure 4 It can be known that:

[0094] The initial total phosphorus (TP) in the overlying water was 1.26 mg / L. By the end of day 1, the TP in Example 2 was 0.62 mg / L, representing a removal rate of 51%. The TP content in the overlying water of Example 1 also decreased by 43%, reaching 0.72 mg / L. In contrast, the reduction in TP in Comparative Examples 1 and 2 was negligible, at only 3%. After 4 days, the TP removal rate in Comparative Example 1 was 88%, while in Examples 1 and 2, the TP removal efficiency was as high as 96%, indicating that the internal electric field accelerated the migration of phosphorus (P) to the sediment. Subsequently, on day 10 of the operation, the TP in the overlying water of all samples remained relatively stable at approximately 0.1 mg / L, indicating that a balance between TP fixation and release had been reached.

[0095] During subsequent operations, the total phosphorus (TP) in the overlying water of all samples remained relatively stable at 0.10–0.15 mg / L. However, significant fluctuations were observed in Comparative Example 1 and Comparative Example 2. For example, the TP in the overlying water of Comparative Example 1 increased again to 0.23 ± 0.01 mg / L on day 46, while that of Comparative Example 2 recovered to 0.45 ± 0.03 mg / L on day 56.

[0096] The results showed that in the absence of a carbon-based electronic conductor, Fe(III) in the anaerobic sediment was easily reduced to Fe(II), and iron-bound phosphorus was released, leading to fluctuations in total phosphorus (TP) in the overlying water. Throughout the entire operation, the TP in the overlying water of Examples 1 and 2 remained lower than in the open-circuit system. The presence of the carbon-based electronic conductor stabilized the TP in the overlying water at 0.04-0.08 mg / L, effectively suppressing the re-release of phosphorus.

[0097] In summary, the device and method for controlling the release of endogenous phosphorus in water based on extracellular electron transfer provided by this invention utilize conductive materials as a medium to shorten the electron transfer distance, reduce electrode costs, and efficiently control endogenous phosphorus in water.

[0098] The above description is only a part of the preferred embodiments of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for controlling the release of endogenous phosphorus from water based on electron transfer, characterized in that, include: Carbon-based electronic conductors, current collectors, support frames, and cover plates; The supporting frame is a hollow structure with openings at both ends; The supporting frame is a hollow cylinder; The cover plate is fixed to one end of the support frame, and the other end of the support frame is used to be inserted into the water sediment for fixation; the cover plate has a central hole, one end of the carbon-based electronic conductor is fixed to the cover plate, and the other end passes through the central hole and is suspended in the hollow structure; the carbon-based electronic conductor is used to collect electrons generated by microbial metabolism and transfer them to the oxygen-rich water surface. The current collector is disposed within the hollow structure of the supporting frame and surrounds the carbon-based electronic conductor; an open circuit is formed between the current collector and the carbon-based electronic conductor; The device also includes an electrical signal acquisition unit. When it is necessary to monitor the electrical signal, the cathode of the electrical signal acquisition unit is connected to the current collector, and its anode is connected to the carbon-based electronic conductor. The electrical signal acquisition unit reads the electrical signal between the current collector and the carbon-based electronic conductor to monitor the concentration changes of organic pollutants in the polluted water body and assess the progress of water body remediation.

2. The device for controlling the release of endogenous phosphorus in water based on electron transfer according to claim 1, characterized in that, On the side of the cover plate facing away from the water, there are several grooves centered on the central hole and along the axial direction of the cover plate; on the end of the carbon-based electronic conductor exposed on the cover plate, there are several screws of a corresponding number along its axial direction centered on the carbon-based electronic conductor. The size of the screws matches the grooves, and one end of the screws is fixed to the carbon-based electronic conductor. Each groove on the cover plate is provided with a matching fastener, and one end of the carbon-based electronic conductor is fixed to the cover plate by the fastener.

3. The device for controlling the release of endogenous phosphorus in water based on electron transfer according to claim 1, characterized in that, The cover plate has an annular groove on the side facing the water, and the hollow cylinder matches the annular groove to achieve a fixed connection between one end of the support frame and the cover plate. Alternatively, the cover plate has an extension edge on the side facing the support frame, and the outer wall of the support frame is interference-fitted with the inner wall of the extension edge to achieve a fixed connection between one end of the support frame and the cover plate.

4. The device for controlling the release of endogenous phosphorus in water based on electron transfer according to claim 1, characterized in that, The cover plate is provided with several sampling and air intake slits.

5. The device for controlling the release of endogenous phosphorus in water based on electron transfer according to claim 1, characterized in that, The collector plate is a stainless steel wire mesh made of stainless steel wire. The hollow structure supporting the skeleton has several through holes on its outer wall.

6. The device for controlling the release of endogenous phosphorus in water based on electron transfer according to claim 1, characterized in that, The cover plate is also provided with Fe(III) injection holes.

7. A method for controlling the release of endogenous phosphorus from water using the apparatus described in any one of claims 1-6, characterized in that, Specifically, the steps include the following: S1. Insert the end of the support frame away from the cover plate into the water sediment, extend one end of the carbon-based electronic conductor into the water of the hollow structure of the support frame, and surround the carbon-based electronic conductor with a mesh plate to form the current collector. S2. Fix the other end of the carbon-based electronic conductor to the other end of the support frame by means of the cover plate, so that the carbon-based electronic conductor is suspended in the water body of the hollow structure of the support frame; S3. An electrical signal acquisition device is used to periodically record the open-circuit voltage between the current collector and the carbon-based electronic conductor in order to monitor the phosphorus fixation and remediation process. The electrical signal acquisition device is a multimeter.

8. The method for controlling the release of endogenous phosphorus from water according to claim 7, characterized in that, Fe(III) is added to the water body supporting the hollow structure through the Fe(III) addition hole on the cover plate. The mass percentage of the Fe(III) addition amount relative to the weight of the water body inside the hollow structure is x, where 0 < x ≤ 5%.

9. The method for controlling the release of endogenous phosphorus from water bodies according to claim 7, characterized in that, The method includes installing several devices for controlling the release of endogenous phosphorus from the treated water area.

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