Three-dimensional positive and negative universal electrode, wastewater treatment system and application

Abstract

The application discloses a three-dimensional positive-negative general electrode, which is used for adsorbing organic pollutants and comprises a three-dimensional skeleton and an adsorption functional layer; the three-dimensional skeleton and / or the adsorption functional layer has conductivity; the adsorption functional layer is covered on the surface of the three-dimensional skeleton, and the constituent material of the adsorption functional layer comprises one or more of conductive polymers, biochar and synthetic carbon. The electrode has large adsorption capacity and high mass transfer efficiency, can efficiently capture organic pollutants in wastewater, and overcomes the problems of traditional physical adsorbents, such as easy loss and difficult recovery, and the like; when the electrode is used as a cathode or an anode to adjust and adsorb organic pollutants under the cooperation of an electric control, the electrode has stronger adsorption capacity and enrichment capacity. The application further provides a wastewater treatment system, which can quickly and completely treat wastewater, and provides applications of the three-dimensional positive-negative general electrode and the wastewater treatment system in treatment of organic pollutants, such as oxytetracycline, methylene blue, methyl orange and ciprofloxacin.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a three-dimensional universal positive and negative electrode, a wastewater treatment system, and its application. Background Technology

[0002] In the treatment of aniline-based wastewater, dye-based wastewater, and antibiotic production wastewater, organic pollutants are the core target. Many organic pollutants in these wastewaters (such as most heterocyclic organic pollutants) are biotoxic, threatening ecosystem security and human health. Traditional treatment methods for these organic pollutants include physical, chemical, and biological methods, all of which have limited removal efficiency. Physical methods primarily use activated carbon, adsorption resins, and other materials as adsorbents to remove organic pollutants from the wastewater.

[0003] Commonly used adsorbents are mainly in granular or powder form. Due to their physical form, granular adsorbents generally have a small specific surface area and low adsorption capacity. While powdered adsorbents have a higher specific surface area, they exhibit unavoidable drawbacks in practical applications. First, the small size of powdered adsorbent particles makes them susceptible to loss due to water flow impact and mechanical agitation during the dynamic process of wastewater treatment. Second, powdered adsorbent particles are easily dispersed and suspended in water, requiring complex separation and recovery processes such as centrifugation and filtration after adsorption. This not only increases equipment investment and operating energy consumption but also presents the problem of incomplete separation and difficult recovery. Third, incompletely recovered powder particles are discharged with the effluent, leading to increased water turbidity. Improper treatment of the adsorbed powder may also cause secondary release of pollutants, violating the environmental protection goals of wastewater treatment.

[0004] Furthermore, the regeneration performance of adsorbents directly determines the economic feasibility of wastewater treatment processes. The regeneration of most adsorbents (such as activated carbon) relies on high-temperature thermal desorption technology, which consumes a lot of energy. Moreover, repeated regeneration can easily damage the adsorption structure, affecting the adsorption performance and sustainable application of the adsorbent.

[0005] Although various studies on the optimization of adsorbent materials have emerged, the aforementioned problems have not yet been fundamentally solved. In this context, wastewater treatment technologies based on electrochemical principles offer a new approach to wastewater treatment, but certain limitations remain in practical applications.

[0006] Taking the widely researched and used bipolar three-dimensional electrode as an example, its specific structure consists of non-conductive particles sandwiched between two electrode plates, using an induced electric field for electrochemical reactions or adsorption. Due to the random particle size and the alternating positive and negative electrodes within the three-dimensional electrode stack, it is difficult to precisely control the potential across the particle electrodes, resulting in poor performance and difficulty in achieving gated removal. Furthermore, when a reverse current is applied to the two electrodes, the irregular particle morphology also results in a reverse induced voltage that only allows the adsorbed contaminants to migrate within a very short distance between the particles, failing to effectively remove them from the system. Summary of the Invention

[0007] The purpose of this invention is to provide a three-dimensional universal positive and negative electrode to solve the problems of difficult recycling and high regeneration energy consumption, while taking into account the adsorption capacity of organic pollutants.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A three-dimensional universal positive and negative electrode is disclosed, the electrode being used to adsorb organic pollutants. The electrode includes a three-dimensional framework and an adsorption functional layer, the three-dimensional framework and / or the adsorption functional layer being conductive; the adsorption functional layer covers the surface of the three-dimensional framework, and the constituent material of the adsorption functional layer includes one or more of conductive polymers, biochar, and synthetic carbon.

[0010] Furthermore, the three-dimensional skeleton is one or a combination of several of the following: mesh skeleton, honeycomb skeleton, and stacked skeleton. The stacked skeleton is an integrated skeleton formed by stacking and constraining granular materials several times.

[0011] Preferably, the mesh skeleton is made of one or more of carbon fiber, metal mesh, and plastic mesh; the honeycomb skeleton is made of one or more of plastic, metal, and carbon materials; and the particulate material includes one or more of ceramic particles, carbon particles, oxide particles, metal particles and their alloy particles, as well as alloy particles formed therefrom.

[0012] The honeycomb skeleton is made of one or more of the following materials: plastic, metal, and carbon; the particulate material includes one or more of the following: ceramic particles, carbon particles, oxide particles, metal particles, and their alloy particles.

[0013] Preferably, the conductive polymer includes one or more of polyaniline, polythiophene, and polypyrrole, or the conductive polymer is a copolymer formed by polymerizing several monomers of aniline, thiophene, pyrrole and their derivatives.

[0014] Preferably, the constituent materials of the adsorption functional layer further include a conductive agent and a binder, wherein the conductive agent is one or a combination of several of acetylene black, Ketjen black, carbon nanotubes, graphite powder, and graphene.

[0015] The present invention also aims to provide a wastewater treatment system for treating aniline-based wastewater and wastewater from the production of dyes and antibiotics. This wastewater treatment system includes a power source, an anode, and a cathode. The cathode or anode is a three-dimensional universal positive and negative electrode as described above. The anode is electrically connected to the positive terminal of the power source, and the cathode is electrically connected to the negative terminal of the power source.

[0016] Preferably, when the constituent material of the adsorption functional layer includes a conductive polymer, the operating voltage between the anode electrode and the cathode electrode is -4.0 to 4.0V; when the constituent material of the adsorption functional layer does not include a conductive polymer, the operating voltage between the anode electrode and the cathode electrode is -10.0 to 10.0V.

[0017] Furthermore, it also includes a flow guiding device, which includes a power pump, an inlet pipe, an outlet pipe, and a hollow distribution box. Two sets of flow holes are evenly arranged on the outside of the distribution box, and the flow holes connect to the internal cavity of the distribution box. The anode and the cathode are installed alternately inside the distribution box and their positions correspond to the two sets of flow holes respectively. One end of the inlet pipe is connected to the power pump, and the other end of the inlet pipe is located outside the distribution box. One end of the outlet pipe is connected to the power pump, and the other end of the outlet pipe connects to the internal cavity of the distribution box, and the connection point is located between the anode and the cathode.

[0018] Furthermore, the diversion box includes a panel, a back plate, and a frame that enclose and form a cavity; the panel and the back plate are spaced apart within the frame and the distance between them is adjustable; the frame limits the edges of the panel and the back plate, and two sets of diversion holes are opened opposite each other on the frame; the end of the water outlet pipe is connected to the cavity through the back plate.

[0019] The present invention also aims to provide the application of the above-mentioned three-dimensional positive and negative universal electrode or the above-mentioned wastewater treatment system, specifically for treating one or more organic pollutants among oxytetracycline, methylene blue, methyl orange, and ciprofloxacin.

[0020] The present invention has the following beneficial effects: 1. The electrode provided by this invention can be used in an electrolytic cell as a universal positive and negative electrode to adsorb organic pollutants. With the application of an appropriate potential for electronic control, the adsorption process can be controlled and enhanced. During electronic control, the voltage is applied directly and precisely to the adsorption functional layer on the electrode surface, which can precisely adjust its surface charge density and redox state. This allows the adsorption function to be activated at a certain potential, resulting in a surge in adsorption performance and a significant increase in adsorption capacity and rate.

[0021] 2. During electronic control adjustment, there is a clear separation between the positive and negative electrodes (unlike the mixed positive and negative electrodes inside the bipolar three-dimensional electrode). A reverse voltage can be applied to reverse the surface state of the three-dimensional universal positive and negative electrode. With the assistance of the electric field, the electrode desorption and regeneration can be carried out, thereby achieving efficient recycling of the adsorbent material with low energy consumption. Compared with the bipolar three-dimensional electrode, the pollutants are more easily driven away from the electrode during desorption of this three-dimensional universal positive and negative electrode, and there is a sufficient area to prevent the pollutants from re-attaching to the counter electrode.

[0022] 3. The broad-spectrum and universal design of the positive and negative universal electrodes perfectly matches the complexity of pollutants. The voltage can be adjusted and treated according to different types of pollutants, making it suitable for both general adsorption treatment of complex wastewater and targeted treatment of single wastewater.

[0023] 4. This invention uses one or more of the following as adsorbent materials: conductive polymers, biochar, and synthetic carbon with abundant pore structures or high-density active sites. These materials are loaded onto a three-dimensional framework to construct a structurally stable adsorption functional layer, which serves as the electrode surface. The adsorption functional layer has both physical adsorption and chemical complexation functions, which can efficiently capture organic pollutants in wastewater and overcome the problems of easy loss and difficult recovery of adsorbents in traditional physical methods.

[0024] 5. This invention uses a three-dimensional skeleton as the electrode substrate, which can provide sufficient area and attachment points for the adsorption functional layer, greatly increasing the adsorption material loading capacity and the contact area between the adsorption material and organic pollutants. At the same time, the numerous interconnected channels in the three-dimensional skeleton can provide an ideal path for the mass transfer process of wastewater treatment, significantly improving the transport rate and flux of organic pollutants to the adsorption functional layer, and achieving a faster and more thorough water purification effect. Attached Figure Description

[0025] Figure 1 This is a comparison image of the three-dimensional skeleton of the present invention before and after covering the adsorption functional layer.

[0026] Figure 2 This is a schematic diagram of the granular material stacking and constraining molding of the present invention.

[0027] Figure 3This is a schematic diagram of the wastewater treatment system of the present invention (the flow guiding device is omitted).

[0028] Figure 4 This is a schematic diagram of the flow divider structure of the present invention (some connecting parts are omitted).

[0029] Figure 5 This is a diagram showing the usage state of the wastewater treatment system of the present invention (the front panel and connectors are omitted).

[0030] Figure 6 a is a graph showing the adsorption capacity test of methyl orange in Experiment 1 of this invention.

[0031] Figure 6 b is a graph showing the methyl orange removal rate test in Experiment 1 of this invention.

[0032] Figure 6 c is the methylene blue adsorption capacity test diagram of Experiment 2 of this invention.

[0033] Figure 6 d is the methylene blue removal rate test graph of Experiment 2 of this invention.

[0034] Figure 6 e is the oxytetracycline adsorption capacity test diagram of Experiment 3 of this invention.

[0035] Figure 6 f is a graph showing the oxytetracycline removal rate test in Experiment 3 of this invention.

[0036] Figure 7 This is a ciprofloxacin adsorption test diagram from Experiment 4 of this invention.

[0037] Figure 8 a is a graph showing the adsorption capacity test of methyl orange in Experiment 5 of this invention.

[0038] Figure 8 b is the methyl orange removal rate test chart of Experiment 5 of this invention.

[0039] Key component markings: 100, 3D universal positive and negative electrode; 110, 3D skeleton; 111, granular material; 120, adsorption functional layer; 200, anode; 300, cathode; 400, flow guiding device; 410, power pump; 420, inlet pipe; 430, outlet pipe; 440, distribution box; 441, cavity; 442, panel; 443, back plate; 4431, outlet hole; 444, frame; 4441, distribution hole; 445, screw; 446, nut; 447, mounting hole. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0041] Example 1 This invention provides a three-dimensional universal positive and negative electrode 100, mainly comprising a three-dimensional framework 110 and an adsorption functional layer 120. For example... Figure 1 As shown, the adsorption functional layer 120 covers the surface of the three-dimensional skeleton 110, and the constituent materials of the adsorption functional layer 120 include one or more of conductive polymers, biochar, and synthetic carbon.

[0042] As the substrate of the electrode, the three-dimensional skeleton 110 can provide a larger specific surface area than the traditional two-dimensional planar electrode substrate, providing sufficient area and attachment points for the adsorption functional layer 120, effectively increasing the loading of the adsorption material and increasing the contact area between the adsorption material and organic pollutants.

[0043] As a constituent material and adsorbent of the adsorption functional layer 120, conductive polymers typically possess a conjugated π-bond structure. They are polymeric materials that, through doping and other treatments, can conduct electricity like metals, exhibiting high active site density and great potential in the treatment of dye-related wastewater. Biochar is a product obtained from biomass such as straw, rice husks, and sawdust through sintering and post-treatment (such as activation and modification). It possesses a rich pore structure and a high active site density. Synthetic charcoal is an artificially synthesized carbon material with specific structures and functions, exhibiting a rich and precisely controllable pore structure.

[0044] Thanks to the material properties of conductive polymers, biochar, and synthetic carbon, one or more of these materials can be used as adsorbents and loaded onto a three-dimensional framework 110 to form a structurally stable adsorption functional layer 120. This layer can then form an integrated electrode with the three-dimensional framework 110, efficiently capturing organic pollutants in wastewater and purifying the wastewater.

[0045] Meanwhile, since the adsorbent material is stably loaded on the surface of the three-dimensional skeleton 110, the electrode does not require additional solid-liquid separation steps after adsorption. The electrode can be directly extracted from the wastewater to complete the adsorbent recovery, which solves the problems of easy loss and difficult recovery caused by traditional adsorbent forms. While taking into account adsorption, it reduces the separation cost of adsorbent material and wastewater and avoids the risk of secondary pollution.

[0046] One or both of the three-dimensional framework 110 and the adsorption functional layer 120 are conductive, enabling the electrode to have continuous conductivity. The conductivity of the three-dimensional framework 110 is mainly achieved through two methods: material selection and conductivity modification. If the three-dimensional framework 110 is made of carbon fiber or metal, it is inherently conductive and can be directly used as the conductive body of the electrode. If the three-dimensional framework 110 is not inherently conductive, a conductive layer can be physically deposited using methods such as copper plating before covering the adsorption functional layer 120, or a conductive polymer can be chemically loaded through methods such as impregnation with conductive carbon black followed by curing or electropolymerization, thus endowing the three-dimensional framework 110 with stable and efficient conductivity.

[0047] Similarly, if the constituent material of the adsorption functional layer 120 is conductive, it can be directly used to construct the adsorption functional layer 120. If the constituent material of the adsorption functional layer 120 is not conductive, it can be made conductive by physically coating a conductive film (such as a carbon film) or chemically impregnating a conductive precursor (such as chemical plating, polyaniline monomer polymerization, etc.) before covering the adsorption functional layer 120.

[0048] Based on the conductivity and integrated design of the three-dimensional framework 110 and the adsorption functional layer 120, this electrode can be used in electrolytic cells to adsorb organic pollutants. This electrode is applicable to both positive and negative electrodes, and under the controlled adjustment of a suitable potential applied in the electrolytic cell, the adsorption process can be controllably enhanced. Under electric field drive, this electrode exhibits stronger adsorption and enrichment capabilities for organic pollutants, significantly improving adsorption capacity and rate. Simultaneously, this electrode can also remove organic pollutants under reverse voltage, enabling efficient recycling of the adsorption material, solving the problem of excessive energy consumption in existing regeneration methods, developing a low-energy-consumption, high-stability regeneration scheme, and improving the economics and feasibility of adsorption technology.

[0049] More specifically, the aforementioned three-dimensional framework 110 employs one or more combinations of mesh frameworks, honeycomb frameworks, and stacked frameworks, forming a three-dimensional adsorption space internally, resulting in a greater increase in the adsorption material loading capacity and the contact area with organic pollutants. Simultaneously, the numerous interconnected channels on the three-dimensional framework 110 provide ideal pathways for the mass transfer process in wastewater treatment, significantly improving the transport rate and flux of organic pollutants to the adsorption functional layer 120. This overcomes the shortcomings of low mass transfer and contact efficiency in traditional two-dimensional electrodes, achieving a faster and more thorough water purification effect.

[0050] The mesh skeleton is made of one or more of carbon fiber, metal mesh, and plastic mesh, with carbon fiber felt being the preferred material. Carbon fiber felt is composed of continuously interwoven carbon fibers, possessing excellent electrical conductivity and mechanical flexibility, as well as a rich porous structure, making it easy to cut and assemble. Furthermore, it promotes electron conduction and mass transfer of target pollutants. The honeycomb skeleton is made of one or more of plastic, metal, and carbon materials, exhibiting good mechanical strength and structural stability.

[0051] like Figure 2As shown, the stacked framework is an integrated framework formed by stacking and constraining granular material 111 through several stacking and constraining processes. The granular material 111 can be in various forms such as granules, flakes, needles, and irregular shapes. The constraining method can be a physical constraining method with detachable connections such as snap-fit ​​connections and threaded connections, or it can be fixed with water-resistant adhesives or other chemical constraining methods. The stacking and constraining can be done in a single process as shown in the figure, or it can be stacked and constrained once and then stacked and constrained again. After constraining and forming, the integrated framework also has a rich porous structure, which has higher permeability than traditional two-dimensional electrode substrates. This is beneficial for increasing the adsorbent loading capacity, increasing the contact area between the adsorbent material and organic pollutants, and optimizing adsorption performance.

[0052] In this embodiment, the particulate material 111 preferably includes one or a combination of ceramic particles, carbon particles, oxide particles, metal particles, and their alloy particles. The particulate material 111 can be first constrained and molded before being covered with the adsorption functional layer 120, or the adsorption functional layer 120 can be covered first before constraining and molding. Ceramic particles provide robust mechanical support and corrosion resistance, while carbon particles impart high specific surface area, conductivity, and surface reactivity to the three-dimensional framework 110. The combination of the two yields better results, synergistically enabling the three-dimensional framework 110 to achieve long-life, stable operation and efficient mass transport in harsh electrochemical environments.

[0053] In addition, a mesh skeleton or a honeycomb skeleton can be used as a structural carrier, with appropriate stacking and constraint of particulate matter 111 inside, to construct a composite three-dimensional skeleton 110 that combines the characteristics of mesh skeleton, honeycomb skeleton and stacked skeleton, so as to achieve synergistic optimization of multiple properties such as mechanical strength, mass transfer efficiency and high density of active sites.

[0054] Based on the actual material selection and requirements, the above-mentioned adsorption functional layer 120 is mainly covered on the three-dimensional skeleton 110 by one or more of the following methods: polymerization, deposition, oxidation / reduction, dissolution coating, coating crosslinking, and coating bonding, so as to form a continuous electrode with adsorption functional layer 120.

[0055] When biochar or synthetic carbon is selected as the adsorbent material, the corresponding adsorption functional layer 120 is preferably coated and attached to the three-dimensional framework 110. In this case, the constituent materials of the adsorption functional layer 120 also include a conductive agent and a binder to firmly adhere the adsorbent material to the three-dimensional framework 110, preventing it from falling off during charging, discharging, or fluid scouring, and constructing a continuous electronic conduction network to ensure efficient transmission of electrical signals or current throughout the electrode structure. Preferably, the conductive agent is one or a combination of acetylene black, Ketjen black, carbon nanotubes, graphite powder, and graphene, which can be added in extremely low amounts to construct a highly efficient three-dimensional electronic conduction network in the three-dimensional framework 110.

[0056] When a conductive polymer is selected as the adsorbent material, the corresponding adsorption functional layer 120 is preferably coated onto the surface of the three-dimensional framework 110 through in-situ polymerization. The conductive polymer includes one or more of polyaniline, polythiophene, and polypyrrole, or the conductive polymer is a copolymer of several monomers of aniline, thiophene, pyrrole and their derivatives. These monomers can be coated onto particulate matter with a certain conductivity in-situ or coated after polymerization to form a composite material.

[0057] In this embodiment, polyaniline is preferably used as the conductive polymer. As a polymer capable of conducting electricity, it is coated onto the three-dimensional framework 110. By applying an appropriate potential, its conductivity, variable and reversible redox state, and molecular structure similar to that of difficult-to-treat heterocyclic compounds, all exhibiting heteroatom ring characteristics, can be fully utilized. As a highly efficient and controllable adsorbent, the redox state of polyaniline can be controlled by an electric field, increasing or altering the affinity (electrostatic force, π-π stacking, van der Waals forces) between polyaniline and heterocyclic pollutant molecules. This can be used for the removal of difficult-to-treat heterocyclic pollutants, achieving enhanced adsorption-desorption under electronic control.

[0058] Example 2 Based on the above embodiment one, as follows Figure 3 As shown, the present invention also provides a wastewater treatment system, including a power supply, an anode 200 and a cathode 300. The anode 200 is electrically connected to the positive terminal of the power supply, and the cathode 300 is electrically connected to the negative terminal of the power supply. The power supply is a DC power supply that can apply a controllable voltage to the anode 200 and the cathode 300.

[0059] The anode 200 or cathode 300 can be selected from the aforementioned three-dimensional universal positive and negative electrode 100. Of course, the specific definitions of the anode 200 and cathode 300 change depending on the voltage polarity conversion between them, and are not fixed to a single electrode. That is, the system can use only one three-dimensional universal positive and negative electrode 100 with adsorption function, and its counter electrode can be a common two-dimensional electrode or a three-dimensional electrode.

[0060] When treating wastewater, applying a suitable positive voltage through a power source can actively control and enhance the adsorption driving force of the three-dimensional universal positive and negative electrode 100. Based on this, the wastewater treatment system can replace the traditional passive adsorption method with active adsorption, significantly improving the flexibility and controllability of the adsorption operation while preserving the original properties of the adsorbent material. Preferably, when treating wastewater, the three-dimensional universal positive and negative electrode 100 acts as the cathode 200 to adsorb organic pollutants, exhibiting strong adsorption performance.

[0061] Under special conditions, such as electrode desorption and regeneration of non-treated wastewater, organic pollutants can be driven away from the three-dimensional positive and negative universal electrode 100 by applying a reverse voltage or alternating voltage through a power source, thus avoiding secondary adsorption of organic pollutants and regenerating the adsorption material in a simple, low-energy-consumption, and highly stable manner.

[0062] Preferably, when the constituent material of the adsorption functional layer 120 includes a conductive polymer, the operating voltage between the anode 200 electrode and the cathode 300 electrode is -4.0 to 4.0V, i.e., a forward voltage of less than 4.0V during wastewater treatment and a reverse voltage of more than -4.0V during desorption. When the constituent material of the adsorption functional layer 120 does not include a conductive polymer, the operating voltage between the anode 200 electrode and the cathode 300 electrode is -10.0 to 10.0V, i.e., a forward voltage of less than 10.0V during wastewater treatment and a reverse voltage of more than 10.0V during desorption. Under this forward voltage, the adsorption capacity and adsorption rate can reach optimal levels.

[0063] like Figure 4 , 5 As shown, the wastewater treatment system also includes a flow guiding device 400, which comprises a power pump 410, an inlet pipe 420, an outlet pipe 430, and a hollow distribution box 440. Two sets of distribution holes 4441 are evenly arranged on the outside of the distribution box 440, and the distribution holes 4441 connect to the internal cavity 441 of the distribution box 440. Anodes 200 and cathodes 300 are installed alternately inside the distribution box 440, with their positions corresponding to the two sets of distribution holes 4441 respectively. After installation, wires can be led out through the corresponding distribution holes 4441. One end of the inlet pipe 420 is connected to the power pump 410, and the other end of the inlet pipe 420 is located outside the distribution box 440. One end of the outlet pipe 430 is connected to the power pump 410, and the other end of the outlet pipe 430 connects to the internal cavity 441 of the distribution box 440 through the outlet hole 4431, with the outlet hole 4431 located between the anode 200 and the cathode 300.

[0064] When treating wastewater, the ends of the diversion device 400 and the inlet pipe 420 can be immersed in the wastewater tank, and the power pump 410 can be turned on to circulate and transport the wastewater, introducing the wastewater into the diversion box 440. This forces the wastewater to penetrate the anode 200 and the cathode 300. With the evenly distributed diversion holes 4441, the organic pollutants in the wastewater can be fully diffused and come into contact with the adsorption functional layer 120 on the three-dimensional positive and negative universal electrode 100, solving the problems of high mass transfer resistance and insufficient contact between pollutants and adsorption materials, and effectively improving adsorption capacity and treatment efficiency.

[0065] Specifically, the diversion box 440 comprises three parts: a panel 442, a back plate 443, and a frame 444, which enclose and form a cavity 441. The panel 442 and the back plate 443 are spaced apart within the frame 444. They are detachably connected together via mounting holes 447 on the back plate 443 and common connecting parts such as screws 445, nuts 446, and rivets, allowing for adjustable spacing. The frame 444 limits the edges of the panel 442 and the back plate 443. Two diversion holes 4441 are opened opposite each other on the frame 444, and the length direction of the diversion holes 4441 is preferably perpendicular to the panel 442 and the back plate 443. The end of the water outlet pipe 430 connects to the cavity 441 through the water outlet hole 4431 on the back plate 443. During periods when not treating wastewater, the panel 442 or the back plate 443 can be removed to install the anode 200 and the cathode 300. Depending on actual needs, the distance between the front plate and the back plate 443 can also be adjusted to adjust the size of the cavity 441 and the amount of water introduced accordingly.

[0066] Example 3 Based on the above embodiments one and two, the present invention also provides the application of the above three-dimensional positive and negative universal electrode 100 or the above wastewater treatment system, specifically: for treating one or more organic pollutants among oxytetracycline, methylene blue, methyl orange and ciprofloxacin, with better selectivity and adsorption efficiency.

[0067] The technical solution of the present invention will be further illustrated below with specific experiments.

[0068] Experiment 1 1. Electrode preparation S1. Preparation of PANI-based mixed solution: Mix 1.5 mL of 7.0% polyvinyl alcohol (PVA) solution, 0.03 g of acetylene black (AB), 0.27 g of polyaniline (PANI) powder, 1.0 mL of ethanol, and 8.0 mL of deionized water in a glass bottle. Dissolve the mixture at room temperature using alternating ultrasonication and stirring to obtain the PANI-based mixed solution.

[0069] S2. Pretreatment of carbon fiber felt (CFF): Cut the carbon fiber felt to a uniform size, such as 1cm × 1cm × 6.8cm. Then, soak the carbon fiber felt in anhydrous ethanol for 30 minutes to remove surface impurities and hydrophobic organic matter. Next, soak it in pure water for 30 minutes to remove residual ethanol and water-soluble impurities. After treatment, dry the carbon fiber felt in a 100℃ oven. After drying, remove it and use it as a three-dimensional skeleton 110. Accurately weigh the carbon fiber felt and record its mass before loading the adsorption functional layer 120.

[0070] S3. Using a dropper, transfer 5 mL of the above PANI-based mixed solution and uniformly drop it onto the surface of the pretreated carbon fiber felt. Finally, transfer the coated carbon fiber felt to a 110℃ constant temperature heating platform for drying for 2 hours. Weigh it again and record its mass after loading to complete the preparation of the PANI / CFF composite three-dimensional positive and negative universal electrode 100.

[0071] 2. Conduct adsorption tests. The prepared PANI / CFF composite three-dimensional positive and negative universal electrode 100 is used as the cathode 300, and the pretreated carbon fiber felt is used as the anode 200. The anode 200 and cathode 300 are filled into the diversion box 440 of the flow guiding device 400, and combined with external DC power supply, power pump 410 and other components to construct a wastewater treatment system for use in wastewater ponds.

[0072] Subsequently, by adjusting the potential with the power supply, the power pump 410 was started to circulate and transport wastewater under conditions of 0V and 0.8V with and without potential, respectively, to conduct cyclic adsorption and test performance. Methyl orange (MO) was selected as the target pollutant for the test, with an adsorption time of 4 hours and an initial concentration of 10 mg / L. During the test, the pH was adjusted by adding 1 mol / L H2SO4 solution or 1 mol / L NaOH solution to control the pH of the system at 4.

[0073] 3. Test Results The adsorption capacity and removal rate of methyl orange within 4 hours are as follows: Figure 6 a and Figure 6 As shown in b, under the test conditions of 0V and 4h, the adsorption efficiency and removal rate of methyl orange were 17.9 mg / g and 22.9%, respectively; under the test conditions of 0.8V and 4h, the adsorption capacity and removal rate of methyl orange were 80.3 mg / g and 77.1%, respectively. This indicates that the above-mentioned three-dimensional universal positive and negative electrode 100 has a better adsorption effect on methyl orange under potential regulation.

[0074] Experiment 2 The difference between this experiment and Experiment 1 is that the target pollutant was replaced with methylene blue (MB). During the experiment, the pH of the system was controlled at 8, the adsorption time was 20 hours, and the initial concentration was 30 mg / L. All other conditions and procedures were the same as in Experiment 1.

[0075] The adsorption capacity and removal rate of methylene blue are as follows: Figure 6 c and Figure 6As shown in Figure d, under the test conditions of 0V and 20h, the adsorption capacity and removal rate of methylene blue were 53.8 mg / g and 17.6%, respectively; under the test conditions of 0.8V and 20h, the adsorption capacity and removal rate of methylene blue were 196.6 mg / g and 64.2%, respectively. This indicates that the above-mentioned three-dimensional universal positive and negative electrode 100 also has a better effect on methylene blue under potential regulation.

[0076] Experiment 3 The difference between this experiment and Experiment 2 is that the target pollutant was replaced with oxytetracycline (OTC). The wastewater was circulated and adsorbed under potential conditions of 0V, 0.4V, and 0.8V to test the performance. All other conditions and procedures were the same as in Experiment 2. The adsorption effect of oxytetracycline is as follows: Figure 6 e and Figure 6 As shown in f, under the test conditions of 0V and 20h, the adsorption capacity and removal rate of oxytetracycline were 16.2 mg / g and 4.9%, respectively; under the test conditions of 0.4V and 20h, the adsorption capacity and removal rate were 22.9 mg / g and 6.8%, respectively; and under the test conditions of 0.8V and 20h, the adsorption capacity and removal rate were 119.8 mg / g and 32.9%, respectively. The results indicate that the aforementioned three-dimensional universal positive and negative electrode 100 also exhibits better adsorption performance for oxytetracycline under potential regulation.

[0077] Although the adsorption capacity and removal rate at 0.4V potential do not increase significantly compared to 0V potential, the adsorption capacity suddenly rises to 119.8mg / g when the potential reaches 0.8V, achieving gated removal effect.

[0078] Experiment 4 The difference between this experiment and Experiment 2 is that the target pollutant was replaced with ciprofloxacin, the pH was controlled at 7, the adsorption time was 4 hours, and the initial concentration was 10 mg / L. The adsorption effect of the above-mentioned PANI / CFF composite material three-dimensional positive and negative universal electrode 100 was compared when connected to the positive and negative electrodes of the power supply, respectively.

[0079] When the three-dimensional universal electrode 100 of the PANI / CFF composite material is connected to the negative terminal of the power supply, i.e., it is the cathode 300, and when it is a PANI / CFF composite material, the positive terminal of the power supply is connected to the pretreated carbon fiber felt CFF. When the three-dimensional universal electrode 100 of the PANI / CFF composite material is connected to the power supply, i.e., it is the anode 200, the negative terminal of the power supply is connected to the pretreated carbon fiber felt CFF.

[0080] During the tests, the potential was controlled at 1.2V, and all other conditions and procedures were the same as in Experiment 1. Adsorption effects were compared... Figure 7As shown in the figure, when the negative electrode of the power supply is connected to the three-dimensional universal electrode 100 of the PANI / CFF composite material (i.e., when it is the cathode 300), the adsorption capacity is 36.4 mg / g after 4 hours. Conversely, when the positive electrode of the power supply is connected to the three-dimensional universal electrode 100 of the PANI / CFF composite material (i.e., when it is the cathode 300), the adsorption capacity is only about 1 mg / g after 4 hours, showing a significant difference in adsorption effect.

[0081] Experiment 5 The adsorption capacity and removal rate of methyl orange by the above-mentioned PANI / CFF composite three-dimensional universal positive and negative electrode 100 were compared using three adsorption modes: static adsorption, stirred adsorption, and breakthrough adsorption (using the aforementioned flow guiding device 400). The test conditions for the three modes were consistent: the initial concentration of methyl orange solution was 10 mg / L, the pH of the system was adjusted to 4, and the adsorption time was 20 h.

[0082] like Figure 8 As shown, in the breakthrough adsorption experiment, the adsorption capacity of methyl orange exhibits a rapid upward trend: reaching approximately 94 mg / g after 1 hour, increasing to 197 mg / g after 4 hours, and finally reaching 383 mg / g after 24 hours. This value is significantly higher than the other two methods—stirred adsorption has an adsorption capacity of only 103 mg / g, and static adsorption has a capacity as low as 45 mg / g. In comparison, the adsorption efficiency and rate of stirred adsorption and static adsorption are both inferior, and the flow guiding device 400 provided by this invention has a significant enhancing effect.

[0083] Although the present invention has been specifically shown and described in conjunction with preferred embodiments, the substances involved and the examples shown are very limited and specific, and it is impossible to list all the substances to be processed and the electrode arrangements. Those skilled in the art should understand that various changes in form and detail to the present invention without departing from the spirit and scope of the invention as defined in the appended claims are all within the scope of protection of the present invention.

Claims

1. A three-dimensional universal positive and negative electrode, characterized in that: The electrode is used to adsorb organic pollutants. The electrode includes a three-dimensional framework and an adsorption functional layer. The three-dimensional framework and / or the adsorption functional layer are conductive. The adsorption functional layer covers the surface of the three-dimensional framework, and the constituent material of the adsorption functional layer includes one or more of conductive polymers, biochar, and synthetic carbon.

2. The three-dimensional universal positive and negative electrode as described in claim 1, characterized in that: The three-dimensional skeleton is one or a combination of several of the following: mesh skeleton, honeycomb skeleton, and stacked skeleton. The stacked skeleton is an integrated skeleton formed by stacking and constraining granular materials several times.

3. The three-dimensional universal positive and negative electrode as described in claim 2, characterized in that: The mesh skeleton is made of one or more of carbon fiber, metal mesh, and plastic mesh; the honeycomb skeleton is made of one or more of plastic, metal, and carbon materials; the particulate material includes one or more of ceramic particles, carbon particles, oxide particles, metal particles, and their alloy particles.

4. The three-dimensional universal positive and negative electrode as described in claim 1, characterized in that: The conductive polymer includes one or more of polyaniline, polythiophene, and polypyrrole, or the conductive polymer is a copolymer formed by polymerizing several monomers of aniline, thiophene, pyrrole and their derivatives.

5. The three-dimensional universal positive and negative electrode as described in claim 1, characterized in that: The constituent materials of the adsorption functional layer also include a conductive agent and a binder, wherein the conductive agent is one or a combination of several of acetylene black, Ketjen black, carbon nanotubes, graphite powder, and graphene.

6. A wastewater treatment system, characterized in that: It includes a power source, an anode, and a cathode, wherein the cathode or anode is a three-dimensional universal positive and negative electrode as described in any one of claims 1-5, the anode is electrically connected to the positive terminal of the power source, and the cathode is electrically connected to the negative terminal of the power source.

7. A wastewater treatment system as described in claim 6, characterized in that: When the constituent material of the adsorption functional layer includes a conductive polymer, the operating voltage between the anode electrode and the cathode electrode is -4.0 to 4.0V; when the constituent material of the adsorption functional layer does not include a conductive polymer, the operating voltage between the anode electrode and the cathode electrode is -10.0 to 10.0V.

8. The wastewater treatment system as described in claim 6, characterized in that: It also includes a flow guiding device, which comprises a power pump, an inlet pipe, an outlet pipe, and a hollow distribution box; two sets of flow holes are evenly arranged on the outside of the distribution box, and the flow holes connect to the internal cavity of the distribution box; the anode and the cathode are installed alternately inside the distribution box and their positions correspond to the two sets of flow holes respectively; one end of the inlet pipe is connected to the power pump, and the other end of the inlet pipe is located outside the distribution box; one end of the outlet pipe is connected to the power pump, and the other end of the outlet pipe connects to the internal cavity of the distribution box, and the connection point is located between the anode and the cathode.

9. A wastewater treatment system as described in claim 8, characterized in that: The diversion box includes a panel, a back plate, and a frame that enclose a cavity; the panel and the back plate are spaced apart within the frame and the distance between them is adjustable; the frame limits the edges of the panel and the back plate, and two sets of diversion holes are opened opposite each other on the frame; the end of the water outlet pipe is connected to the cavity through the back plate.

10. The application of the three-dimensional universal positive and negative electrode as described in any one of claims 1-5 or the wastewater treatment system as described in any one of claims 6-9, characterized in that: Used to treat one or more organic pollutants, including oxytetracycline, methylene blue, methyl orange, and ciprofloxacin.

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