Electrochemical advanced oxidation electrolytic bath

Abstract

The invention belongs to the field of electrochemical wastewater treatment, and relates to an electrochemical advanced oxidation electrolytic bath which comprises a shell, at least one group of electrode assemblies arranged in the shell, a bottom inlet and a top outlet, the electrode assembly is composed of net-shaped anodes and net-shaped cathodes which are alternately stacked, the net hole directions of the net-shaped anodes and the net-shaped cathodes are perpendicular to each other, wastewater vertically flows through electrode holes from bottom to top and continuously collides with an electrode body, the anodes adopt titanium-based stretching nets and are coated with titanium black catalysts, and hydroxyl radicals can be efficiently generated in situ at normal temperature and normal pressure; and refractory organic matters are directly mineralized. According to the invention, a mass transfer mode is converted from diffusion leading to convection leading through a vertical cross-flow design, the reaction efficiency and the current utilization rate are remarkably improved, chemical agents are not required to be added, secondary pollution is avoided, and the device is suitable for high-salt, high-toxicity and difficult-to-biochemically-treated wastewater treatment and has the advantages of compact structure, stable operation, high engineering applicability and the like.

Description

Technical Field

[0001] This invention relates to the field of electrochemical wastewater treatment, and in particular to an electrochemical advanced oxidation electrolyzer. Background Technology

[0002] In the field of electrochemical wastewater treatment, existing technical solutions mainly revolve around two types of reactor design and their corresponding degradation mechanisms, but they all have obvious technical bottlenecks.

[0003] (1) Mainstream reactor configuration: parallel plate reactor

[0004] Currently, the most widely used type is the parallel plate electrochemical reactor. In this type of reactor, the cathode and anode are parallel flat plates. The wastewater to be treated flows in the channels between the electrode plates, parallel to the electrode surface, rather than through the electrodes themselves. This configuration determines that its core mass transfer mechanism is: the transport of reactants (pollutant molecules) from the bulk fluid to the electrode surface must rely on slow molecular diffusion, a process that mainly occurs within the fluid boundary layer at the electrode surface.

[0005] (2) Mainstream degradation mechanism: indirect electrochemical oxidation

[0006] Due to the low mass transfer efficiency of parallel plate reactors, pollutants have difficulty directly contacting the electrodes, limiting direct electrochemical oxidation. Therefore, existing technologies heavily rely on indirect electrochemical oxidation mechanisms. This technology does not primarily depend on direct electron transfer of pollutants at the electrode surface, but instead utilizes the electrolysis process to generate a recyclable "oxidation medium" (such as the active chlorine species ClO) in situ on the electrode surface. - Persulfate (S₂O₈) 2- These highly active mediators diffuse into the bulk solution and undergo redox reactions with pollutants, thereby achieving degradation.

[0007] (3) Inherent defects and limitations of existing technologies

[0008] Although parallel plate reactors and indirect electrochemical oxidation technology have been widely used, they have the following inherent drawbacks that are difficult to overcome:

[0009] ①Low mass transfer efficiency. The parallel flow design makes the mass transfer process entirely controlled by slow boundary layer diffusion, becoming a "rate-controlling step" that increases the reaction rate. Pollutants are difficult to be transported to the electrode surface quickly and effectively, resulting in low overall reactor treatment efficiency, high energy consumption, and long hydraulic residence time.

[0010] ② Electrode passivation is easy and the active area is limited. Contaminants or their polymerization products tend to accumulate on the flat electrode surface, forming a passivation film that hinders electron transfer, causing the current efficiency to decrease sharply over time. At the same time, the limited two-dimensional planar electrode structure restricts the specific surface area available for reaction.

[0011] In summary, existing technologies are limited by the outdated "diffusion mass transfer" mode of parallel plate reactors and their over-reliance on the single reaction pathway of "indirect oxidation," resulting in significant shortcomings in terms of treatment efficiency, energy consumption, versatility, and environmental friendliness.

[0012] Publication No. CN111051248A describes a hydrogen-water generation device comprising: a mesh-like electrode plate; an electrolytic cell in which three or more of the aforementioned electrode plates are arranged facing each other at predetermined intervals, with a water inlet on one side of the electrode plates and a water outlet on the other side; and a power circuit unit that applies voltage to each of the electrode plates, causing current to flow between adjacent electrode plates and between electrode plates sandwiching other electrode plates, thereby performing electrolysis. Water is injected into the electrolytic cell through the inlet, moving from the inlet side to the outlet side. The moving water is electrolyzed by the electrode plates to generate an aqueous solution containing hydrogen, which is then discharged from the outlet. However, this technical solution employs the common method of increasing the surface area to improve efficiency, but the fluid flow direction is parallel to the electrodes, resulting in limited efficiency improvement.

[0013] Therefore, developing a novel electrochemical reactor technology that can fundamentally enhance mass transfer and synergize multiple degradation mechanisms has become a key issue that urgently needs to be addressed in this field. Summary of the Invention

[0014] In view of this, the present invention aims to propose an electrochemical advanced oxidation electrolyzer to solve the problems of severe concentration polarization, high energy consumption and low processing efficiency of existing flat plate electrolyzers.

[0015] The main problems with existing technologies are as follows: Traditional parallel plate reactors consist of two parallel plate electrodes (anode and cathode) immersed in an electrolyte. Reactants can only reach the electrode surface to react by slowly diffusing through the diffusion layer, and products also need to diffuse away. At high current densities, reactants on the electrode surface are rapidly consumed, while reactants further away cannot be replenished in time, leading to a sharp drop in the electrode surface concentration. This generates a huge concentration overpotential, making the actual reaction voltage much higher than the theoretical value, thus reducing energy efficiency. The limiting current density of parallel plate reactors is very low, making high-rate reactions impossible. The effective reaction area is only equal to the geometric projection area of ​​the electrodes. The reactor chamber is filled with a large amount of electrolyte that cannot be effectively utilized, resulting in very low efficiency.

[0016] The core of this invention lies in the fact that the reactor includes at least one through-flow electrode unit, which is composed of porous electrodes. The flow direction of the wastewater to be treated is designed to pass perpendicularly through the body of the porous electrode, rather than parallel to its surface. This structural innovation brings two synergistic enhancement effects:

[0017] ① Mass transfer mode transformation: The mass transfer mechanism is transformed from slow "diffusion-dominated" to efficient "convection-dominated", which greatly enhances the transfer rate of pollutants to the electrode surface and completely breaks the mass transfer bottleneck of traditional reactors.

[0018] ② Synergistic reaction pathway: Under cross-flow operation, when pollutants flow through the electrode channels, they can undergo direct electrochemical oxidation on the electrode surface, or be oxidized by highly active oxidation media generated in situ on the electrode surface and carried out in time by fluid convection, thus realizing in-situ coupling and synergistic enhancement of direct oxidation and indirect oxidation.

[0019] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0020] This invention discloses an electrochemical advanced oxidation electrolyzer, comprising a shell, at least one set of electrode assemblies disposed within the shell, an inlet at the bottom of the shell, and an outlet at the top of the shell;

[0021] The electrode assembly includes alternatingly stacked mesh anodes and mesh cathodes, and a conductive rod penetrating the anode or cathode;

[0022] The mesh openings of the mesh anode and mesh cathode are perpendicular to each other;

[0023] After the wastewater to be treated enters through the inlet, it flows vertically upward through the pores of the mesh anode and mesh cathode, and undergoes an electrochemical oxidation reaction under the action of an external electric field to degrade organic pollutants. The treated liquid is then discharged from the outlet.

[0024] Furthermore, the electrode assembly is provided in two sets, namely an upper electrode assembly and a lower electrode assembly. Each set of electrode assemblies is connected to an independent DC power supply, or connected in series or in parallel before being connected to the DC power supply.

[0025] Furthermore, both the mesh anode and the mesh cathode are made of titanium stretched mesh with rhomboid mesh openings that are evenly distributed; the reaction zone surface of the mesh anode is coated with a catalyst.

[0026] Furthermore, the catalyst is titanium suboxide.

[0027] Furthermore, the mesh anode and mesh cathode are kept apart by insulating isolation nails fixed on the cathode mesh, and the distance is 2–5 mm.

[0028] Furthermore, the conductive rod includes a base plate and studs welded thereon for fixing the electrode mesh and conducting current; a sealing gasket is provided between the conductive rod and the end flange to prevent electrolyte leakage.

[0029] Furthermore, the end of the electrode assembly is fixed by a fixing plate made of insulating material, and the fixing plate is pre-tightened by a fastening nut to keep the entire electrode assembly structurally stable.

[0030] Furthermore, the housing is made of an oxidation- and corrosion-resistant material, preferably fiberglass.

[0031] Furthermore, both the inlet and outlet are equipped with flange interfaces for connecting external pipelines.

[0032] Furthermore, the electrolytic cell does not require the addition of chemical reagents during operation. Through the synergistic effect of direct electrochemical oxidation as the main method and indirect electrochemical oxidation as the auxiliary method, organic pollutants are mineralized into CO2, H2O and inorganic salts.

[0033] Compared with the prior art, the electrochemical advanced oxidation electrolyzer of the present invention has the following advantages:

[0034] 1. This invention employs a vertical through-flow mesh electrode structure, allowing the wastewater to enter from the bottom inlet of the electrolytic cell and directly penetrate the alternating mesh anode and cathode. Under the action of an applied electric field, pollutants are directly oxidized in situ. The through-flow characteristic significantly enhances the mass transfer process of pollutants to the electrode surface, transforming the traditional reaction mode that relies on diffusion mass transfer into one dominated by convection mass transfer. This greatly improves the mineralization rate of organic pollutants and the current utilization efficiency, effectively solving the technical bottlenecks of severe concentration polarization, high energy consumption, and low treatment efficiency in existing flat-plate electrolytic cells.

[0035] 2. This invention, by setting the mesh directions of the mesh anode and mesh cathode to be perpendicular to each other and arranging them with a narrow spacing of 2–5 mm, not only enhances the disturbance and mixing effect of the fluid when passing through the electrode layer and suppresses the formation of local concentration dead zones, but also constructs a highly active and stable anode system through a titanium stretched mesh matrix combined with a titanium suboxide catalytic coating. At the same time, the entire electrolytic cell does not require the addition of any chemical reagents and can achieve complete mineralization of recalcitrant organic matter solely through electrical energy, with no secondary pollution, low operating costs, and the shell made of corrosion-resistant fiberglass material and modular assembly of core components, possessing excellent engineering adaptability and long-term operational reliability. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0037] Figure 1 This is a schematic diagram of the electrolytic cell structure of the present invention;

[0038] Figure 2 This is a schematic diagram of the electrode assembly structure of the present invention;

[0039] Figure 3 This is a schematic diagram of the conductive rod structure of the present invention;

[0040] Figure 4 This is a schematic diagram of the anode mesh structure of the present invention;

[0041] Figure 5 This is a schematic diagram of the cathode mesh structure of the present invention;

[0042] Figure 6 This is a schematic diagram of the stacked structure of the anode mesh and cathode mesh of the present invention;

[0043] Figure 7 This is a schematic diagram of the fixed disk structure of the present invention;

[0044] Figure 8 This is a schematic diagram of the external structure of the electrolytic cell of the present invention;

[0045] Figure 9 This is a schematic diagram showing the dimensions of the rhomboid holes in the mesh anode of the present invention;

[0046] Figure 10 This is a schematic diagram showing the dimensions of the rhomboid holes in the mesh cathode of the present invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1. Electrode assembly; 101. End flange; 102. Sealing gasket; 103. Conductive rod; 1031. Base plate; 1032. Stud; 104. Titanium gasket; 105. Mesh anode; 106. Mesh cathode; 107. Insulating isolation nail; 108. Fixing plate; 109. Fastening nut; 2. Housing; 3. Inlet; 4. Outlet; 5. Support base. Detailed Implementation

[0049] To make the technical means and objectives and effects of the present invention easier to understand, the embodiments of the present invention will be described in detail below with reference to specific illustrations.

[0050] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state. They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0051] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] like Figure 1 As shown, the present invention provides an electrochemical advanced oxidation electrolyzer, mainly comprising a shell 2, one or more sets of electrode assemblies 1 disposed within the shell, an inlet 3 located at the bottom of the shell, an outlet 4 at the top, and a support base 5 for support and fixation. The electrolyzer is installed vertically, and the wastewater to be treated flows from bottom to top through the electrode area, undergoing an electrochemical oxidation reaction under the action of an applied DC electric field. This vertical flow layout aligns the fluid flow direction with the direction of gravity, which facilitates the natural upward floating and discharge of gas bubbles generated during the electrolysis reaction, preventing gas films from covering the electrode surface and reducing the effective reaction area, thereby maintaining high current efficiency and oxidation stability.

[0054] Compared with the prior art, the significant advantages of this invention are as follows: existing electrochemical wastewater treatment reactors mostly adopt a parallel flow design, with the fluid flowing parallel along the surface of the electrode plates. The mass transfer process is mainly based on boundary layer diffusion, which limits the efficiency. Moreover, its degradation mechanism mainly relies on indirect electrochemical oxidation, that is, the removal of pollutants is achieved by generating soluble oxidizing media through electrolysis.

[0055] In a fundamentally different manner, this invention innovates the mass transfer mode of the fluid within the reactor by allowing the fluid to be treated to pass vertically through the porous electrode body. This not only transforms the mass transfer mechanism from inefficient diffusion-dominated to highly efficient convection-dominated, greatly enhancing the transport rate of reactants to the electrode surface, but also achieves synergistic enhancement of direct and indirect electrochemical oxidation in the reaction mechanism. Pollutants can be directly degraded by electron transfer on the electrode surface, and can also undergo highly efficient oxidation reactions with highly reactive mediators (such as ·OH, active chlorine, etc.) generated in situ on the electrode surface and rapidly carried out by convection. This dual enhancement of mass transfer and reaction brought about by structural innovation fundamentally improves the reactor's treatment efficiency and energy utilization.

[0056] Furthermore, the electrolyzer of this invention possesses convective mass transfer characteristics, which significantly reduces the thickness of the diffusion layer, allowing reactants to rapidly reach the electrode surface and products to rapidly exit, enabling operation at very high current densities without concentration polarization. The mesh electrode also prevents small bubbles generated during the electrolysis reaction from agglomerating into large bubbles, avoiding the contamination and reduced electrode contact area caused by large bubbles. The mesh electrode provides a vast effective reaction area, several times that of a flat plate electrode. Good fluid distribution contributes to a more uniform current distribution, preventing localized overheating or side reactions.

[0057] In this embodiment, the electrolytic cell includes two sets of electrode assemblies 1, namely a lower electrode assembly and an upper electrode assembly, arranged vertically along the axial direction of the shell 2. Each set of electrode assemblies 1 is independently connected to a DC power supply with a rated current of 1000 A. Specifically, the anode terminal of the lower electrode assembly is connected to the positive terminal of power supply A, and the cathode terminal is connected to the negative terminal of power supply A; the upper electrode assembly is connected to power supply B, realizing segmented power supply and flexible control. This segmented power supply method can dynamically adjust the current density of each segment according to the influent water quality or treatment target. For example, a high current density is used in the front segment to rapidly degrade high-concentration pollutants, while a lower current density is used in the rear segment for deep mineralization. This avoids energy waste at the front end and ensures that the effluent meets the standards, significantly improving the overall energy efficiency and operational adaptability of the system.

[0058] Alternatively, the two sets of electrode assemblies 1 can be connected in series or parallel through an external circuit and then connected to the same DC power supply. For example, the anode terminal of the lower electrode assembly is connected to the positive terminal of power supply A, and the cathode terminal is connected to the negative terminal of power supply A; the upper electrode assembly is connected to power supply B accordingly, realizing segmented power supply and flexible control.

[0059] It should be understood that the above electrical connection methods are merely examples. In actual engineering applications, connection modes such as independent power supply, parallel current amplification, or series voltage boosting can be flexibly selected according to the influent water quality, treatment scale, and energy efficiency requirements, all without departing from the technical concept of this invention.

[0060] like Figure 2 As shown, each electrode assembly 1 consists of an end flange 101, a sealing gasket 102, a conductive rod 103, a titanium gasket 104, multiple mesh anodes 105, multiple mesh cathodes 106, insulating isolation nails 107, a fixing plate 108, and fastening nuts 109. The mesh anodes 105 and mesh cathodes 106 are arranged in alternating layers, with 56 and 55 pieces respectively. A uniform 3 mm gap is maintained between them by insulating isolation nails 107 fixed to the cathode mesh, effectively preventing short circuits between the anode and cathode and ensuring flow channel consistency. This narrow-gap design significantly shortens the ion migration path, reduces the ohmic resistance of the cell, and, combined with the vertical through-flow, significantly thins the mass transfer boundary layer, breaking through the limiting current density of traditional flat-plate electrolyzers and achieving high-throughput, high-efficiency pollutant removal.

[0061] like Figure 3 As shown, the conductive rod 103 is constructed by welding a base plate 1031 and a stud 1032, penetrating the entire electrode stack and serving as both a mechanical support structure and a current transmission channel. The mesh anode 105 is electrically connected to the positive terminal of the power supply via the conductive rod 103, while the mesh cathode 106 is electrically connected to the negative terminal of the power supply via an independent conductive structure or a connector insulated from the conductive rod 103, ensuring mutual isolation between the anode and cathode electrical circuits. A sealing gasket 102, made of oxidation-resistant fluororubber, is provided between the conductive rod 103 and the end flange 101 to ensure that the electrolyte does not leak along the conductive rod 103 to the outside of the housing 2. Preferably, three conductive rods 103 are provided, evenly distributed along the length of the base plate 1031, penetrating the entire mesh anode 105 or mesh cathode 106. This ensures that the mesh anode 105 and mesh cathode 106 do not interfere with each other after assembly, avoiding localized overheating or uneven reaction, and improving the consistency of electrode lifespan and mineralization efficiency.

[0062] Preferably, the base plate 1031 is arc-shaped, with the chord direction being the length direction.

[0063] In addition, the mesh cathode 106 collects current through the titanium current collector ring at the end and leads it to the negative power supply via the waterproof terminal block on the side wall of the housing 2, which effectively reduces contact resistance, prevents local corrosion caused by single-point lead wires, and improves the reliability of long-term operation of the cathode.

[0064] A titanium gasket 104 is fitted onto the conductive rod 103, located between the end flange 101 and the outermost electrode mesh, to uniformly transmit the clamping force and prevent galvanic corrosion. Using a titanium gasket 104 made of the same material as the electrode eliminates contact between dissimilar metals, fundamentally avoiding the risk of galvanic corrosion and ensuring the structural integrity and electrical stability of the electrode stack in a strong oxidizing environment.

[0065] like Figure 4 and Figure 5 As shown, both the mesh anode 105 and the mesh cathode 106 are made of 1.5 mm thick titanium stretched mesh, with a circular fan-shaped structure with one side cut off. The fan-shaped units are assembled to form a nearly circular complete electrode disk, with a through hole in the center for the conductive rod 103 to pass through, facilitating circumferential mounting within the cylindrical shell 2. The mesh openings are rhomboid and evenly distributed. The reaction zone surface of the mesh anode 105 is coated with a titanium suboxide catalyst to enhance the generation efficiency of hydroxyl radicals. In this embodiment, the mesh cathode 106 is not coated with a catalyst and only acts as an electron acceptor in the hydrogen evolution or oxygen reduction reaction. In other embodiments, a hydrogen evolution or oxygen reduction catalytic coating can also be applied to improve cathode efficiency. The titanium suboxide coating exhibits high oxygen evolution overpotential and excellent hydroxyl radical generation activity, maintaining good stability under high salt and wide pH conditions, significantly superior to traditional noble metal oxide coatings, and is particularly suitable for complex water quality scenarios such as shipbuilding and chemical industries. The mesh anode 105 and mesh cathode 106 are arranged opposite each other, and are stacked alternately layer by layer at the end away from the through hole through which the conductive rod 103 passes.

[0066] Preferably, the major axis of the rhombus of the mesh anode 105 is oriented east-west, and the major axis of the rhombus of the mesh cathode 106 is oriented north-south, meaning the mesh directions of the two are perpendicular to each other. See [reference needed]. Figure 6 The orthogonal mesh structure causes the fluid to continuously change its flow direction as it passes through the electrodes layer by layer, forming a three-dimensional turbulence effect. This continuously disrupts the concentration boundary layer, significantly enhances turbulence intensity, and promotes mass transfer and renewal of pollutant molecules to the active sites of the electrodes. The measured mass transfer coefficient is more than twice that of the parallel pore structure, effectively suppressing concentration polarization.

[0067] The insulating isolation pin 107 is made of polytetrafluoroethylene (PTFE) or ceramic. One end is fixed to the mesh cathode 106, and the other end abuts against the adjacent mesh anode 105, ensuring a constant 3 mm gap between the anode and cathode and reliable electrical isolation. PTFE or ceramic materials possess high insulation, excellent resistance to strong oxidation, and good mechanical strength. They do not age or deform under long-term high-voltage electrolysis, maintaining a stable electrode spacing over a long period, eliminating the risk of short circuits, and ensuring the safe and continuous operation of the system.

[0068] like Figure 7As shown, the end of electrode assembly 1 is fixed and limited by an insulating fixing plate 108, and a pre-tightening force is applied by a fastening nut 109 to maintain the structural stability of the entire electrode stack during operation, preventing misalignment due to water flow impact or thermal expansion. The fixing plate 108 has a through hole in the center that matches the conductive rod 103, and its outer edge is attached to the inner wall of the housing 2. Preferably, the fixing plate 108 is made of polytetrafluoroethylene or reinforced PP. Such polymer insulating materials are not only corrosion-resistant and lightweight, but also effectively absorb thermal stress and mechanical vibration, preventing deformation or breakage of the electrode mesh caused by rigid constraints, and improving the operational reliability of the equipment under varying operating conditions.

[0069] like Figure 8 As shown, the shell 2 is made of fiberglass, possessing both high strength and excellent resistance to corrosion from strong oxidizing media. Both the inlet 3 and outlet 4 are equipped with DN80 PN10 CPVC flange interfaces for easy and quick connection to external pipelines. The support base 5 is made of SS304 stainless steel, 20 mm thick, and has four mounting holes for securely fixing the electrolytic cell to the equipment bracket. The fiberglass shell exhibits excellent resistance to strong oxidizing substances such as hydroxyl radicals, ozone, and hypochlorous acid, completely solving the problem of easy corrosion and perforation of traditional metal shells in high-oxidizing environments, significantly extending the equipment's service life and reducing maintenance costs.

[0070] The operation process of this embodiment is as follows: High-salt wastewater containing organic pollutants (COD ≈ 800 mg / L, TDS ≈ 3%) enters the electrolytic cell from the bottom inlet 3 at a flow rate of 3 m³ / h. Under the action of an applied electric field (total voltage approximately 12 V, current density approximately 30 mA / cm²), water molecules are oxidized on the anode surface to generate a large number of ·OH free radicals, and organic matter is directly mineralized on the anode surface into CO2, H2O, and inorganic salts. The treated effluent is discharged from the top outlet 4, with a COD removal rate of over 95%, meeting reuse or discharge standards. The entire process requires no chemical additives, produces no sludge, consumes only electricity, and is safe and environmentally friendly. Thanks to the efficient convective mass transfer mechanism and the synergistic effect of the highly active anode, this invention can achieve rapid mineralization of recalcitrant organic matter such as aniline, phenols, and dyes at ambient temperature and pressure, with energy consumption below 8 kWh / kg COD, reducing energy consumption by more than 30% compared to traditional Fenton or ozone oxidation processes, truly achieving green, low-carbon, and sustainable deep wastewater treatment.

[0071] Example 1

[0072] Electrolytic cell outline drawing as follows Figure 8As shown, the outer shell 2 is made of fiberglass, which meets both strength requirements and suitability for environments with oxidizing media. The support base 5 is made of SS304 stainless steel, with a thickness of 20mm to meet strength requirements. The inlet 3 and outlet 4 use DN80 PN10 CPVC flanges.

[0073] Mesh anode 105 Figure 9 As shown, the mesh anode 105 has a thickness of 1.5 mm, a circular shape with one side cut off, and is made of titanium stretched mesh with rhomboid mesh openings that are evenly distributed. A titanium suboxide catalyst is coated in the reaction zone. Preferably, the rhomboid mesh anode 105 has a major axis of 6 mm and a minor axis of 3 mm.

[0074] Mesh cathode 106 Figure 10 As shown, the mesh cathode 106 is 1.5mm thick, circular in shape with one side cut off, and is made of titanium stretched mesh with rhomboid mesh openings that are evenly distributed. The reaction zone is not coated with a catalyst. Each mesh anode 105 is fixed with 6 insulating spacers. Preferably, the rhomboid shape of the mesh cathode 106 has a major axis of 6mm and a minor axis of 3mm.

[0075] Each electrode assembly 1 includes 56 mesh anodes 105 and 55 mesh cathodes 106. The mesh cathodes 106 and mesh anodes 105 are arranged alternately in a stacked manner, with the mesh openings perpendicular to each other. The spacing between the mesh anodes 105 and mesh cathodes 106 is 3 mm.

[0076] Each electrolytic cell contains two sets of electrode assemblies, one set at the bottom and the other at the top. For example... Figure 1 As shown. The anode terminal of the lower electrode assembly 1 is connected to the positive terminal of a DC power supply A with a rated current of 1000A, and the cathode terminal of the lower electrode assembly 1 is connected to the negative terminal of the same power supply A. The anode terminal of the upper electrode assembly 1 is connected to the positive terminal of another DC power supply B with a rated current of 1000A, and the cathode terminal of the upper electrode assembly 1 is connected to the negative terminal of the same power supply B.

[0077] Wastewater containing organic pollutants enters the electrolytic cell from the lower inlet at a flow rate of 3 m³ / h. Under the action of direct current, the organic pollutants are mineralized into CO2, H2O and inorganic salts through electrode catalytic oxidation. The wastewater is then discharged through the upper outlet of the electrolytic cell. The concentration of pollutants in the discharged liquid meets the discharge or reuse standards, and is then discharged or recycled for reuse.

[0078] Its core advantage lies in the fact that it does not require the addition of chemical agents, has no secondary pollution, and is suitable for the treatment of wastewater with high salt content, high toxicity, and difficulty in biodegradation.

[0079] In summary, the present invention has the following advantages:

[0080] ① Revolution in Mass Transfer Mode: The mass transfer mechanism is transformed from a slow "diffusion-dominated" to a highly efficient "convection-dominated" mode, greatly enhancing the transfer rate of pollutants to the electrode surface. This completely breaks through the mass transfer bottleneck of traditional reactors, significantly improving mass transfer efficiency. Convection mass transfer replaces diffusion mass transfer, increasing the mass transfer rate by more than an order of magnitude. This fundamentally solves the problem of reaction rate control steps. Moreover, the vertical flushing action of the fluid effectively cleans the electrode surface, preventing pollutant deposition and passivation film formation, and maintaining the long-term activity of the electrode. In addition, the extremely high specific surface area and mass transfer efficiency result in a smaller reactor volume and a reduction of more than 10% in energy consumption required to treat a unit of pollutant.

[0081] ② Synergistic Reaction Path: When wastewater carrying pollutants flows vertically through the intricate internal channels of the electrode, intense convective shearing occurs between the fluid and the electrode surface. This results in a very high probability that pollutants will directly collide with or come extremely close to the electrode surface. At this point, direct electrochemical oxidation leverages its advantages of "short-range and rapid" degradation, quickly degrading pollutants close to the surface through direct electron transfer. This process is highly efficient and does not rely on intermediate media in the solution. Simultaneously, on the inner surface of the electrode channels, electrolysis of water continuously generates a large number of highly reactive oxide species, most typically hydroxyl radicals. In a parallel plate reactor, these hydroxyl radicals can only diffuse slowly. However, in a through-flow structure, the convection of the fluid instantly carries these newly generated hydroxyl radicals away from the electrode surface and into the bulk fluid. These carried-out hydroxyl radicals exert their advantages of "long-range and broad-spectrum" degradation in the bulk fluid, indiscriminately and thoroughly oxidizing and degrading other pollutant molecules in the solution that have not directly contacted the electrode surface. This overcomes the limitation of the limited distance of direct oxidation. The core design of the through-flow structure is not simply a coupling of direct oxidation and indirect oxidation, but also a deep integration of the two from the perspectives of physical space and reaction kinetics.

[0082] The above are merely preferred embodiments of the present invention and are 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. An electrochemical advanced oxidation electrolytic cell, characterized in that, It includes a housing (2), at least one set of electrode assemblies (1) disposed within the housing, an inlet (3) disposed at the bottom of the housing and an outlet (4) disposed at the top. The electrode assembly (1) includes alternatingly stacked mesh anodes (105) and mesh cathodes (106), and a conductive rod (103) penetrating the anode or cathode. The mesh directions of the mesh anode (105) and the mesh cathode (106) are perpendicular to each other; After the wastewater to be treated enters from the inlet (3), it flows vertically upward through the pores of the mesh anode (105) and mesh cathode (106), and undergoes an electrochemical oxidation reaction under the action of an external electric field to degrade organic pollutants. The treated liquid is discharged from the outlet (4).

2. The electrochemical advanced oxidation electrolytic cell according to claim 1, characterized in that, The electrode assembly (1) is provided in two groups, namely the upper electrode assembly and the lower electrode assembly. Each group of electrode assemblies is connected to an independent DC power supply, or the two groups of electrode assemblies (1) are connected in series or in parallel before being connected to the DC power supply.

3. The electrochemical advanced oxidation electrolytic cell according to claim 1, characterized in that, Both the mesh anode (105) and the mesh cathode (106) are made of titanium stretched mesh with rhomboid mesh openings that are evenly distributed; the reaction zone surface of the mesh anode (105) is coated with a catalyst.

4. The electrochemical advanced oxidation electrolytic cell according to claim 3, characterized in that, The catalyst is titanium suboxide.

5. The electrochemical advanced oxidation electrolytic cell according to claim 1, characterized in that, The mesh anode (105) and mesh cathode (106) are kept apart by insulating isolation nails (107) fixed on the cathode mesh, the distance being 2–5 mm.

6. The electrochemical advanced oxidation electrolyzer according to claim 1, characterized in that, The conductive rod (103) includes a base plate (1031) and a stud (1032) welded thereon, for fixing the electrode mesh and conducting current; a sealing gasket (102) is provided between the conductive rod (103) and the end flange (101) to prevent electrolyte leakage.

7. The electrochemical advanced oxidation electrolytic cell according to claim 1, characterized in that, The end of the electrode assembly (1) is fixed by a fixing plate (108) made of insulating material. The fixing plate (108) is pre-tightened by a fastening nut (109) to keep the entire electrode assembly structurally stable.

8. The electrochemical advanced oxidation electrolyzer according to claim 1, characterized in that, The shell (2) is made of an oxidation- and corrosion-resistant material, preferably fiberglass.

9. The electrochemical advanced oxidation electrolytic cell according to claim 1, characterized in that, Both the inlet (3) and outlet (4) are equipped with flange interfaces for connecting external pipelines.

10. The electrochemical advanced oxidation electrolyzer according to claim 1, characterized in that, The electrolytic cell does not require the addition of chemical reagents during operation. Through the synergistic effect of direct electrochemical oxidation as the main method and indirect electrochemical oxidation as the auxiliary method, organic pollutants are mineralized into CO2, H2O and inorganic salts.

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