A three-dimensional electrochemical reactor

Abstract

The present invention belongs to the field of electrochemical engineering technology and relates to a three-dimensional electrochemical reactor, comprising: a reactor housing assembly, a three-dimensional electrode module, a counter electrode module, a diaphragm or polymer separator, and an external power supply. The counter electrode modules are arranged in pairs, the paired counter electrode modules clamp the three-dimensional electrode module in the middle, the diaphragm or polymer separator is clamped between the electrode surface of the counter electrode module and the electrode surface of the three-dimensional electrode module, and the three-dimensional electrode module, the counter electrode module, the diaphragm or polymer separator are arranged in the inner cavity of the reactor housing assembly; the present invention enables fluid to flow through the interior and surface of the three-dimensional electrode, transfers the main electrochemical reaction site to the interior and surface of the three-dimensional electrode, and ensures sufficient flow and mixing of the fluid between the electrodes while shortening the electrode distance as much as possible, thereby reducing solution resistance, lowering cell voltage, improving current efficiency, and avoiding increased energy consumption and equipment damage caused by excessively high voltage.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical engineering and relates to a three-dimensional electrochemical reactor. Background Art

[0002] In the field of electrochemical engineering, electrochemical reactors are widely used in many fields such as water treatment and electrochemical synthesis. Traditional electrochemical reactors are mainly divided into two categories: batch electrolytic cells and flow electrolytic cells.

[0003] One of the most common types of electrochemical reactors is a batch electrolysis cell, where reactants react in a fixed volume of solution until preset conditions, such as a predetermined reaction time, are reached. However, this type of reactor has several limitations: for example, the concentration of reactants decreases over time during the reaction, which can lead to mass transfer limitations, reducing reaction rate and current efficiency.

[0004] Flow electrolysis cells maintain a constant flow rate through the reactor, ensuring uniform flow of reactants across the electrode surface, thereby improving reaction uniformity, operational continuity, and efficiency. Despite their operational continuity and efficient mass transfer, flow electrolysis cells also face the following limitations in practical applications: 1) Efficiency at low conductivity: Flow electrolysis cells typically exhibit low current efficiency under low conductivity conditions due to insufficient ion concentration, which limits charge transfer and reduces the electrochemical reaction rate. 2) Uneven fluid distribution: Flow electrolysis cells place high demands on fluid distribution. Uneven fluid distribution can easily lead to localized insufficient reaction or reactant accumulation, impacting the overall reaction and reducing mass transfer efficiency. 3) Interference with side reactions at the counter electrode: In addition to the primary reaction at the working electrode, unwanted side reactions can occur at the counter electrode in flow electrolysis cells. These side reactions can interfere with the primary reaction, reducing reaction efficiency and, in electrochemical synthesis applications, impacting product selectivity and purity. While side reactions can be minimized by selecting specific electrode materials or optimizing operating conditions, completely avoiding them in complex chemical systems is extremely difficult.

[0005] To overcome these problems, existing technologies have proposed several improvements. For example, they employ high-surface-area three-dimensional electrode materials (such as carbon felt, graphite felt, and carbon fibers) to increase the contact area between reactants and electrodes, thereby improving mass transfer efficiency and reaction rate; optimize fluid dynamics and rationally design flow channel structures to achieve more uniform fluid distribution; and employ selective electrode materials and various ion exchange membranes to reduce unnecessary side reactions.

[0006] However, these existing methods still have the following shortcomings: Electrochemical reactors have difficulty operating under low-conductivity conditions: When treating low-conductivity water (such as tap water, agricultural water, livestock water, industrial circulating water, and chemical reaction water), the solution resistance increases significantly, leading to an increase in cell voltage and significantly increased energy consumption, thus affecting the overall efficiency of the reactor. Furthermore, low-conductivity conditions are prone to increased electrode polarization and localized current density unevenness, further weakening electrode activity.

[0007] Side reactions on the counter electrode are difficult to suppress, which reduces the reaction selectivity and efficiency: Although the main reaction occurs on the working electrode, unnecessary side reactions on the counter electrode are often unavoidable. These side reactions may affect the efficiency of the main reaction, the selectivity and purity of the product. Although these side reactions can be reduced by selective electrode materials or optimizing operating conditions, complete suppression remains difficult in complex chemical systems. The use of membranes (such as proton exchange membranes) can reduce the occurrence of side reactions, but it will significantly increase the cost and complexity of the system, and the membrane material may also increase the resistance of the system, further reducing its applicability under low conductivity conditions.

[0008] High energy consumption and poor economic efficiency: In low-conductivity environments, achieving the desired reaction effect typically requires increasing voltage or current, which significantly increases energy consumption, reduces economic efficiency, and may pose safety risks, such as electrode damage and the dissolution of heavy metal ions (especially ruthenium-iridium-titanium electrodes and lead dioxide electrodes). High energy consumption and high costs further limit the widespread use of existing electrochemical reactors in large-scale industrial applications.

[0009] Therefore, there is an urgent need for a device or method suitable for low-conductivity fluids that can effectively suppress side reactions at the counter electrode, thereby improving overall reaction efficiency. At the same time, avoiding the use of complex reaction equipment and high-cost ion exchange membranes to reduce overall costs is also a factor that must be considered. Summary of the Invention

[0010] The technical solution adopted by the present invention to solve the technical problem is: a three-dimensional electrochemical reactor, the three-dimensional electrochemical reactor includes multiple reactor units, and the multiple reactor units and related accessories and equipment together constitute a complete electrochemical reactor. A single reactor unit includes: a reactor housing assembly, a three-dimensional electrode module, a counter electrode module, a diaphragm or polymer separator, and an external power supply. The inner cavity of the reactor housing assembly is used to accommodate the core electrode module and related accessories. The electrolyte solution can be a single liquid or a gas-liquid mixture. Almost all of the electrolyte solution passes through and reacts inside the three-dimensional electrode. The housing only plays a protective role, and its inner wall does not even need to be soaked with liquid; therefore, the reaction is more sufficient and is not affected by the side reaction on the counter electrode. The three-dimensional electrode module and the counter electrode module respectively serve as electrodes for the electrochemical reaction, and their polarity (anode or cathode) can be adjusted according to needs during operation. The three-dimensional electrode module serves as both an electrode and the interior of the three-dimensional electrode module also serves as a channel for the flow of the electrolyte solution;

[0011] The diaphragm or polymer separator is used to separate adjacent electrode pairs and keep them at a small distance from each other. It limits the convective diffusion of the electrolyte solution from the three-dimensional electrode module to the counter electrode module without hindering the transfer of ions between the two electrodes. The diaphragm or polymer separator acts to hinder convection. In essence, the solutions on both sides are completely connected, but the convective exchange rate of the solutions is extremely slow. Therefore, the diaphragm or polymer separator can effectively limit the reaction of the counter electrode and control the electrolyte flow through the interior of the three-dimensional electrode with a large area for electrochemical reaction.

[0012] The counter electrode modules are arranged in pairs, the paired counter electrode modules sandwich the three-dimensional electrode module in the middle, the diaphragm or polymer separator is sandwiched between the electrode surface of the counter electrode module and the electrode surface of the three-dimensional electrode module, and the three-dimensional electrode module and the counter electrode module are electrically connected to the positive and negative electrodes of the external power supply respectively;

[0013] The upper and lower ends of the reactor housing assembly are provided with fluid inlets and outlets. The upper inlet guides the electrolyte solution into the interior of the three-dimensional electrode through a guide tube, while the lower outlet guide tube discharges the treated electrolyte solution out of the current reactor unit.

[0014] The three-dimensional electrode module is made of carbon felt, graphite felt, carbon fiber, nickel fiber, stainless steel fiber, titanium foam, and nickel foam, and its surface can be modified by physical or chemical methods to optimize or adjust the electrochemical properties of the electrode surface to meet different electrochemical application requirements;

[0015] The electrode module has at least good electrical conductivity, corrosion resistance and electrochemical inertness. The material of the electrode module includes: titanium suboxide, ruthenium-iridium-titanium alloy, platinum group metals, titanium-based alloys, graphite, precious metal oxides or other conductive materials suitable for electrochemical reactions;

[0016] The diaphragm or polymer separator has a certain porosity and permeability to ensure efficient ion transfer between the electrodes while hindering convection. The material of the diaphragm or polymer separator can be selected from chemically stable polymer materials, including polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), nylon, cellulose, and composite materials thereof. The structure of the diaphragm or polymer separator includes mesh, microporous film, fabric, or a multilayer composite structure of the above materials.

[0017] When the electrolyte solution flows through the inside of the three-dimensional electrode module, an external power supply supplies power to the three-dimensional electrode module and the counter electrode module, and the ions in the electrolyte solution can pass through the diaphragm or polymer partition and move between the three-dimensional electrode module and the counter electrode module to form an electrical circuit; since the three-dimensional electrode module has a large-area porous structure, the contact area between the electrolyte solution and it is much larger than the contact area with the counter electrode module, and the diaphragm or polymer partition imposes convective mass transfer restrictions on ion transfer, thereby limiting the electrochemical reaction mainly to the three-dimensional electrode module, so as to improve the utilization efficiency of the electrode and the selectivity of the reaction products.

[0018] Preferably, the three-dimensional electrochemical reactor is further provided with an electrode polarity conversion system, which is electrically connected to the external power supply and the three-dimensional electrode module and the counter electrode module respectively. The electrode polarity conversion system is used to switch the electrode polarity of the external power supply to the three-dimensional electrode module and the counter electrode module, thereby realizing selective control of the oxidation reaction and reduction reaction on the three-dimensional electrode; the electrode polarity conversion system includes an H-bridge circuit, a relay, a solid-state relay, a semiconductor switch or a bidirectional DC power supply, etc., to meet the requirements of high-frequency polarity conversion or large current.

[0019] More preferably, the polarity conversion frequency range of the electrode polarity conversion system is 10 -6 Hz to 10 6 Hz.

[0020] More preferably, the three-dimensional electrochemical reactor is further provided with a modular series-parallel interface for connecting a plurality of reactor units to realize series or parallel operation and control the liquid flow through the fluid inlet and outlet; the modular series-parallel interface includes: a regulating valve, a proportional control valve, a peristaltic pump, the outer end interface of the modular series-parallel interface is connected to the fluid storage unit, the inner end interface of the modular series-parallel interface is connected to the inner cavity of the reactor housing assembly, and the modular series-parallel interface can be realized by means of quick connectors, plug-in interfaces, bolt / nut fixing interfaces, etc., to meet different flow regulation requirements, and the modules can be directly connected or indirectly connected through pipes. A flow regulation function (such as a regulating valve, a proportional control valve, a peristaltic pump, etc.) can be added to the interface to realize precise control of the fluid flow between different modules, optimize the reaction efficiency of each module, and when a flow regulator (such as a peristaltic pump) with an active liquid delivery function is used, the system can realize flexible arrangement in a non-vertical direction.

[0021] More preferably, the three-dimensional electrochemical reactor is also provided with a fluid control unit and a control system; the fluid control unit is connected to the fluid inlet of the first-stage reactor unit, and is used to transport the electrolyte solution to the fluid inlet; the control system is electrically connected to the fluid control unit and the electrode polarity conversion system, and is used to control the delivery flow of the fluid control unit and the electrode polarity conversion of the electrode polarity conversion system; the fluid control unit, such as a peristaltic pump, is directly connected in one direction through a pipeline, and transports the liquid from the storage container to the fluid inlet of the first-stage reactor; the modular series-parallel interface is used for subsequent flow control and diversion control, from the first-stage reactor to the subsequent multi-stage reactor.

[0022] Preferably, the three-dimensional electrochemical reactor can be operated in a single-stage mode, or a multi-stage electrochemical reaction system can be formed by connecting multiple reactor units in series or in parallel;

[0023] In a single-stage electrochemical reaction system, the electrolyte solution that has passed through the reactor is directed to a fluid storage unit for storage, and then circulated back to the fluid inlet of the single-stage reactor to achieve a cyclic electrochemical reaction process.

[0024] In a multi-stage electrochemical reaction system, the electrolyte solution from the previous unit or external fluid source is directed to the three-dimensional electrode module of the next unit through a modular series-parallel interface to serve as the input electrolyte solution for the new stage of electrochemical reaction.

[0025] Preferably, one of the paired electrodes in the counter electrode module is an inert splint, and the other of the paired electrodes is connected to an external power supply and used as a counter electrode; that is, one of the counter electrodes is allowed to be replaced with a non-electrode material, and only one side of the counter electrode is working.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention reasonably shortens the electrode spacing by optimizing the reactor structure. By optimizing the reactor structure and reasonably shortening the electrode spacing, the fluid can flow through the interior and surface of the three-dimensional electrode, and the main electrochemical reaction site is simultaneously transferred to the interior and surface of the three-dimensional electrode. While shortening the electrode spacing as much as possible, the present invention still ensures sufficient flow and mixing of the fluid, and can ensure the contact area and contact efficiency between the fluid and the electrode surface. The shortening of the electrode spacing reduces the influence of solution resistance, reduces the cell voltage, improves current efficiency, and avoids increased energy consumption and equipment damage caused by excessive voltage.

[0028] 2. The present invention introduces a polymer separator to suppress side reactions; the present invention uses cheap and readily available polymer mesh materials as separation media to limit the convection and diffusion of the solution between the working electrode and the counter electrode without hindering ion transfer; therefore, the present invention effectively reduces the occurrence of side reactions on the counter electrode, improves the selectivity of the reaction and the yield of the target product.

[0029] 3. The present invention increases the surface area of ​​the electrode by using three-dimensional electrode materials with high specific surface area; the present invention selects three-dimensional electrode materials with high conductivity and high specific surface area such as carbon felt and graphite felt, which increases the active surface area of ​​the electrode, promotes the mass transfer of reactants and electron transfer, and improves the reaction rate and efficiency.

[0030] 4. The present invention reduces costs and improves economic efficiency; the materials used in the present invention, such as polymer separators and three-dimensional electrode materials, are low-cost, and the design simplifies the reactor structure, reduces manufacturing and maintenance costs, and improves the economic efficiency of the system; in addition, the present invention can prevent electrode passivation, promote self-cleaning of the electrode surface, reduce polarization effects, and further improve reaction efficiency and equipment life through electrode polarity conversion.

[0031] 5. The present invention enhances system flexibility through modular design. The reactor of the present invention adopts a modular design, and multiple three-dimensional electrode modules and supporting components can be combined and stacked according to needs, which facilitates the expansion and maintenance of the system and adapts to different scales and application scenarios. The reactor of the present invention has broad application potential in water treatment, electrochemical synthesis, energy conversion and other fields, especially in low conductivity environments, showing excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of equipment connections for a three-dimensional electrochemical reactor according to the present invention;

[0033] Figure 2 It is the basic structure diagram and working schematic diagram of the reaction unit of the present invention;

[0034] Figure 3This is a performance comparison chart between the present invention and the traditional intermittent electrolytic cell;

[0035] Figure 4 This is a schematic diagram of the control of applying positive / negative potential to achieve oxidation reaction / reduction reaction dominance in the present invention;

[0036] Figure 5 It is a schematic diagram of the change of ciprofloxacin removal rate over time at an initial concentration of 20 mg / L according to the present invention.

[0037] Among them, 1. Reactor housing assembly; 2. Three-dimensional electrode module; 3. Counter electrode module; 4. Diaphragm or polymer partition; 5. Wire connection end; 6. Electrode polarity conversion system; 7. Modular series-parallel interface; 8. Fluid inlet and outlet; 9. Fluid control unit; 10. External power supply; 11. Control system; 12. Fluid storage unit. DETAILED DESCRIPTION

[0038] The following will provide a clear and complete description of the relevant technologies in the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] refer to Figures 1 to 5 , the three-dimensional electrochemical reactor of the present invention, such as Figure 1 and Figure 2 As shown, it includes a reactor housing assembly 1, a three-dimensional electrode module 2, a counter electrode module 3, a diaphragm or polymer separator 4, a wire connection terminal 5, an electrode polarity conversion system 6, a modular series-parallel interface 7, a fluid inlet and outlet 8, a fluid control unit 9, an external power supply 10, a control system 11, a fluid storage unit 12, and other necessary piping and connectors.

[0040] Furthermore, the reactor housing assembly 1 adopts a modular design and can be flexibly configured as an independent unit or a multi-reactor group according to the processing requirements to enhance the processing capacity and operational flexibility of the system. Each reactor housing assembly 1 is mainly composed of a reactor shell, a shell and a reaction chamber, and has corrosion resistance, insulation and appropriate mechanical strength. In addition, the reactor shell is provided with a gas outlet for emergency pressure relief, as well as a reserved interface for ventilation and heat dissipation to ensure smooth temperature control and gas exchange inside the reactor. The reactor housing assembly 1, the three-dimensional electrode module 2, the counter electrode module 3, the diaphragm or polymer partition 4, the wire connection end 5, and the fluid inlet and outlet 8 together constitute a complete reactor unit.

[0041] Furthermore, the three-dimensional electrode module 2 has good fluid permeability, high conductivity and a large specific surface area, ensuring that the fluid fully flows and transfers mass in the electrode, thereby improving the efficiency of the electrochemical reaction. The module can be made of materials such as carbon felt, graphite felt, carbon fiber cloth, nickel fiber, stainless steel fiber, and can optimize the electrochemical properties of the electrode surface through physical or chemical modification to meet different application requirements. It is worth noting that the "fluid" in the present invention generally refers to a substance that can flow, including pure fluids and liquid-gas mixtures, which can be transmitted in the reactor and undergo electrochemical reactions.

[0042] Furthermore, the electrode module 3 has at least good electrical conductivity, sufficient corrosion resistance, and electrochemical inertness. Its size and shape (such as plate-shaped electrode, mesh-shaped electrode, or with a certain curvature) can be adjusted to match the reactor housing assembly 1 and the three-dimensional electrode module 2.

[0043] Furthermore, the membrane or polymer separator 4 should have a certain porosity and permeability to ensure efficient transfer of ions between the electrodes to form an electrical circuit; the structure and material design of the membrane or polymer separator 4 can be adjusted, including thickness, surface morphology, and degree of fit between the electrodes, to control the fluid flow path so that the fluid only flows through the interior of the three-dimensional electrode module 2, or flows through the reserved gaps inside the three-dimensional electrode and between the electrode pairs at the same time; the porosity, permeability and number of stacking layers of the membrane or polymer separator 4 can be controlled to adjust the exchange efficiency of the solution between the electrode pairs, reduce the occurrence of undesirable side reactions, and optimize the mass transfer efficiency and selectivity of the electrochemical reaction; the membrane or polymer separator 4 has sufficient chemical stability and can maintain its function in a variety of chemical environments; the membrane or polymer separator 4 can be made of a single layer of material, or stacked or composited by multiple layers of the same or different materials to meet the needs of different applications.

[0044] Furthermore, the wire connection end 5 can be connected to the circuit using metal clamps, screw fixation, welding, plug-in terminals, crimping, etc., depending on specific needs. Its material should be highly conductive copper, aluminum, or silver-plated materials to ensure current transmission efficiency and reduce power loss. To prevent corrosion and current leakage, the connection end 5 should be protected with an insulating and corrosion-resistant material (such as silicone glue, silicone rubber, polyethylene, or polyvinyl chloride). Gold-plated connectors can also be used as a material option to improve long-term stability.

[0045] Furthermore, the electrode polarity conversion system 6 can be implemented by an H-bridge circuit, a relay, a solid-state relay, a semiconductor switch, or a bidirectional DC power supply to meet the requirements of high-frequency polarity conversion or large current. The system can achieve timed or conditional conversion of electrode polarity through manual or automatic control (such as PLC or timer), and the operating frequency range is 10 -6 Hz to 10 6Hz. During a reversal cycle, the time the current remains in a certain direction can be adjusted arbitrarily between 0% and 100% as needed. The system can be equipped with filters, overcurrent protection devices, varistors, and other components to ensure voltage and current stability. Electrode polarity reversal features include: flexible adjustment of electrode operating polarity to control oxidation / reduction reaction types; promoting self-cleaning of the electrode surface to prevent passivation and polarization effects; and controlling reaction selectivity for more precise product control.

[0046] Furthermore, the modular series-parallel interface 7 can be implemented by means of quick connectors, plug-in interfaces, bolt / nut fixing interfaces, etc. to meet different technical requirements and application scenarios. The modules can be directly connected or indirectly connected through pipes. A flow regulation function (such as a regulating valve, a proportional control valve, a peristaltic pump, etc.) can be added to the interface to achieve accurate control of the fluid flow between different modules and optimize the reaction efficiency of each module. When a flow regulator (such as a peristaltic pump) with an active liquid delivery function is used, the system can achieve flexible arrangement in a non-vertical direction.

[0047] Furthermore, the fluid inlet and outlet 8 is designed to efficiently collect fluid discharged from the previous unit or an external fluid source (such as a liquid storage tank or liquid supply system), and precisely direct it to the three-dimensional electrodes of the next module, serving as the starting point for the next stage of electrochemical reaction. By adjusting the scale of individual reactors, such as the length and related structure of the three-dimensional electrode modules, the reaction order can be flexibly controlled, where the reaction order n is a natural number ≥ 1.

[0048] Furthermore, the fluid control unit 9 is designed to efficiently collect fluid discharged from the previous unit or fluid storage unit 12 (such as a liquid storage tank or liquid supply system) and accurately guide the fluid to the three-dimensional electrode of the next module or fluid storage unit 12, which serves as the starting point of the electrochemical reaction, thereby serving as the starting point of a new electrochemical reaction, thereby guiding the electrochemical reaction in this module to proceed smoothly. By adjusting the scale of a single reactor, such as the length of the three-dimensional electrode module and its associated related structures, the number of reaction orders can be flexibly controlled, where the reaction order n is a natural number ≥ 1.

[0049] Furthermore, the fluid control unit 9 is designed to drive the fluid from the fluid storage unit 12 or the previous reactor unit to a designated location, ensuring that the fluid can be stably and accurately delivered to the three-dimensional electrodes or other areas of the next-level module. The fluid control unit 9 can control the fluid transfer between different modules by adjusting the flow rate, pressure, or delivery method according to system requirements. This process can be achieved by devices such as peristaltic pumps, gas-liquid mixing pumps, diaphragm pumps, screw pumps, gas-liquid booster pumps, and fluid control valves, with peristaltic pumps being preferred.

[0050] Furthermore, the external power supply 10 must be able to provide a suitable voltage or current to support the total load when multiple modules are operated in series or in parallel, ensuring that the electrochemical reaction is carried out efficiently and stably. The power supply can be a DC or AC power supply, preferably supporting integration with an automatic control interface (such as a PLC or other control system), and can remotely adjust parameters such as voltage and current through the automatic control system. The power supply can record parameters such as voltage and current in real time for easy monitoring and debugging, and is used to calculate system performance indicators (such as energy consumption and current efficiency).

[0051] Furthermore, the control system 11 serves as the core management unit of the entire three-dimensional electrochemical reactor, responsible for precise control and coordination of various modules such as fluids, reaction conditions, and power supplies. The control system can be a programmable logic controller (PLC), a distributed control system (DCS), an embedded control system, a combination of a human-machine interface (HMI) and a PLC or DCS, or a combination of a supervisory control and data acquisition (SCADA) system and a PLC or DCS, preferably a programmable logic controller.

[0052] Furthermore, multiple fluid storage units 12 are provided for storing fluids to be processed, in process, or after processing. The fluid storage units 12 are connected to the fluid control unit 9 via pipelines to ensure a stable supply and circulation of fluid to the reactor units, ensuring the continuous and stable operation of the electrochemical reaction. Furthermore, by changing the piping connection method, it is also possible to allow the fluid to pass through multiple stages of series-connected reactor units continuously and complete the reaction in real time. Alternatively, it is possible to allow the fluid to pass repeatedly through a single or multiple-stage reactor and complete the reaction over a period of time.

[0053] Furthermore, other necessary piping and connectors include various combinations of fluid delivery pipelines, temporary fluid storage containers, flow meters and sensors, return pipes and bypass systems, quick connectors and valves.

[0054] Example

[0055] Example 1: To simulate the actual operating conditions of low-conductivity water, this example uses sodium sulfate as the supporting electrolyte and adjusts the fluid (deionized water) conductivity to 271 μS / cm. Under these conditions, the performance of the three-dimensional electrochemical reactor of the present invention is compared with that of a conventional intermittent electrolytic cell.

[0056] In the three-dimensional electrochemical reactor, a G280A graphite felt electrode is used as the core of the three-dimensional electrode module; a ruthenium-iridium-titanium electrode is used as the counter electrode; and a nylon-cellulose composite material is used as the separator between the three-dimensional electrode and the counter electrode. The projected area of ​​the graphite felt electrode is also controlled to be 20 cm 2The three-dimensional electrode, separator, and counter electrode are closely connected. At this time, the fluid mainly flows through the interior of the three-dimensional electrode module and an electrochemical reaction occurs there. In this embodiment, a constant current density of 20 mA / cm 2 , the total current is 0.4A, the system enters a stable state after working for 1 minute, and the cell voltage is measured to be 4.56V (such as Figure 3 a), the reactor can operate stably.

[0057] As a control, the conventional intermittent electrolytic cell used a flat ruthenium-iridium-titanium electrode as the working electrode and a titanium electrode as the counter electrode, with the electrode spacing set to 1.0 cm. The projected area of ​​the working electrode was also 20 cm. 2 Under the conditions of 5.00V, 7.50V and 10.0V, the programmable power supply was used to test the system and the test results were obtained after the system stabilized for 1 minute. The results showed that under the above different voltage gradients, the corresponding currents were only 0.0467A, 0.0538A and 0.0806A (as shown in Figure 2). Figure 3 b, 3c, and 3d), which is much lower than the working current of the new reactor and cannot achieve the preset 20 mA / cm 2 Current density (corresponding to a current of 0.4 A). This shows that conventional electrochemical reactors cannot effectively meet the reaction requirements under low conductivity conditions, while the three-dimensional electrochemical reactor of the present invention can operate stably and meet the expected operating conditions. The corresponding detailed results are shown in Figure 2. Figure 3 As shown in e.

[0058] Example 2: Using the same experimental conditions as in Example 1 (current density of 20 mA / cm 2 , the three-dimensional electrode projection area is 20cm 2 ) was used to test a low-conductivity phenolic water sample, where phenols were used as indicators for electrochemical oxidation reactions to evaluate the effectiveness of the reaction. This example controlled the dominant direction of the reaction by adjusting the polarity of the three-dimensional electrode, namely electrochemical oxidation (EO, in which case the three-dimensional electrode acts as the anode) and electrochemical reduction (ER, in which case the three-dimensional electrode acts as the cathode). Figure 4 As shown, Figure 4 a and Figure 4 The only difference from experiment b is the control of electrode polarity. Figure 4 In Figure a, the 3D electrode acts as the anode. After passing through the two-stage series reactor, the phenolic water sample appears distinctly black, indicating the formation of quinones. This demonstrates that under electrochemical oxidation conditions, after a brief reaction phase (only two reactor stages), phenols are rapidly oxidized to form quinones.

[0059] In contrast, Figure 4b shows the experimental results when the three-dimensional electrode serves as the cathode. Under the same current density, despite the phenolic water sample being processed through more four-stage series reactors, the solution remained clear and transparent, with no visible black change. This indicates that in the electrochemical reduction (ER)-dominated reaction, phenols were not oxidized, the formation of quinones was almost completely suppressed, and the electrochemical oxidation reaction was effectively isolated in this system.

[0060] The above experimental comparison shows that the polarity of the 3D electrode plays a crucial role in the dominant reaction and can be effectively controlled. When the 3D electrode acts as the anode, the electrochemical oxidation (EO) reaction dominates; when the 3D electrode acts as the cathode, the oxidation reaction is almost completely suppressed.

[0061] Example 3: Under the same experimental conditions as Example 1 (current density of 20 mA / cm 2 , the three-dimensional electrode projection area is 20cm 2 ) to treat ciprofloxacin in low conductivity water (20 mg / L, used to simulate the condition of water bodies seriously contaminated by antibiotics - the solubility of ciprofloxacin under neutral conditions and room temperature is about 30 mg / L). The fluid circulates in the same single-stage reactor and continues to be treated for a period of time. The pH of the sample itself is maintained unchanged during the test, and the samples before and after treatment are tested using UV-vis. The removal rate at different time points is calculated based on the maximum absorbance at 266 nm. Figure 5 As can be seen, the removal rate of ciprofloxacin increased significantly with treatment time. After 3 hours of treatment, the removal rate reached 68.51%. After 6 hours, the removal rate further increased to 87.04%. After 9 hours, the removal rate was 94.09%. After 15 hours of treatment, the removal rate reached a maximum of 97.77%. These results indicate that the removal efficiency of ciprofloxacin in low-conductivity water increases significantly over time, especially within the first 6 hours (reaching 87.04%, close to 90% removal), after which it stabilizes.

[0062] Example 4: Under experimental conditions similar to those of Example 3, ciprofloxacin (initial concentration of 1000 μg, used to simulate antibiotic contamination conditions that are closer to real contaminated water environments) was treated in low-conductivity water. The experiment was conducted under a constant current of 0.4A, using a three-dimensional electrode system, and the fluid circulated in the same single-stage reactor for a reaction. The treatment lasted for 4 hours, and the voltage was always less than 5V during this process. Samples were taken at different time points and the removal rate was tested. HPLC with a lower detection limit was used to analyze the changes in the concentration of ciprofloxacin in the samples. The results showed that the removal rate of ciprofloxacin increased significantly with increasing reaction time, as shown in Table 1:

[0063]

[0064] Table 1

[0065] Table 1 shows the changes in key parameters during the treatment of 1000 μg of ciprofloxacin using the present invention. After 0.5 hours of reaction, the removal rate reached 77.4%; after 2 hours, the removal rate further increased to 98.1%; and after 3 and 4 hours, the removal rate reached 99.6%, indicating near-complete removal. These experimental results demonstrate that under these reaction conditions, the ciprofloxacin removal efficiency rapidly increased within the first 2 hours and stabilized thereafter, achieving near-complete removal. This demonstrates the method's high efficiency and applicability in simulating the treatment of actual contaminated water.

[0066] In summary, the reactor of the present invention has the potential for modular assembly and can be flexibly configured as an independent unit or a multi-reactor group according to processing requirements, thereby enhancing the processing capacity and operational flexibility of the system. By optimizing the reactor structure and reasonably shortening the electrode spacing, the fluid can flow through the interior and surface of the three-dimensional electrode, and the main electrochemical reaction site is transferred to the interior and surface of the three-dimensional electrode. While shortening the electrode spacing as much as possible, it ensures sufficient flow and mixing of the fluid between the electrodes, reduces the solution resistance, reduces the tank voltage, improves the current efficiency, and avoids increased energy consumption and equipment damage caused by excessive voltage. In addition, the present invention uses a cheap and readily available polymer separator as a separating medium, which limits the convection diffusion of the solution from the three-dimensional electrode module to the counter electrode without hindering the efficient transfer of ions between the two electrodes. This effectively reduces the occurrence of side reactions on the counter electrode and improves the efficiency and selectivity of the electrochemical reaction. Through the electrode polarity conversion system, the reaction type is further controlled, the self-cleaning of the electrode surface is promoted, and the electrode passivation and polarization effects are prevented. Therefore, the reactor can operate stably under low conductivity conditions, effectively suppress the interference of side reactions on the counter electrode, and improve the efficiency and stability of the electrochemical reaction. It is suitable for many fields such as water treatment and electrochemical synthesis. It has the advantages of high efficiency, energy saving, and wide application range, and has good application prospects.

[0067] It should be emphasized that the above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A three-dimensional electrochemical reactor, characterized in that: The three-dimensional electrochemical reactor comprises a plurality of reactor units, wherein a single reactor unit comprises: a reactor housing component (1), a three-dimensional electrode module (2), a counter electrode module (3), a diaphragm or polymer separator (4), and an external power supply (10). The inner cavity of the reactor housing component (1) is used to accommodate the electrode module as a core and related accessories. The three-dimensional electrode module (2) and the counter electrode module (3) respectively serve as electrodes for electrochemical reactions. The three-dimensional electrode module (2) serves as both an electrode and an interior of the three-dimensional electrode module (2) also serves as a channel for the flow of an electrolyte solution. The diaphragm or polymer separator (4) is used to separate adjacent electrode pairs and keep them at a distance from each other, and to limit the convection diffusion of the electrolyte solution from the three-dimensional electrode module (2) to the counter electrode module (3) without hindering the transfer of ions between the two electrodes; The counter electrode modules (3) are arranged in pairs, and the paired counter electrode modules (3) clamp the three-dimensional electrode module (2) in the middle, and the diaphragm or polymer separator (4) is clamped between the electrode surface of the counter electrode module (3) and the electrode surface of the three-dimensional electrode module (2), and the three-dimensional electrode module (2) and the counter electrode module (3) are electrically connected to the positive and negative electrodes of the external power supply (10) respectively; The reactor housing assembly (1) is provided with fluid inlets and outlets (8) at the upper and lower ends, wherein the inlet at the upper end guides the electrolyte solution into the interior of the three-dimensional electrode through a flow guide pipe, while the flow guide pipe at the lower end outlet discharges the treated electrolyte solution out of the current reactor unit; The three-dimensional electrode module (2) is made of carbon felt, graphite felt, carbon fiber, nickel fiber, stainless steel fiber, titanium foam, and nickel foam; The counter electrode module (3) has at least good electrical conductivity, corrosion resistance and electrochemical inertness, and the material of the counter electrode module (3) includes: titanium suboxide, ruthenium-iridium-titanium alloy, platinum group metals, titanium-based alloys, graphite, and precious metal oxides; The membrane or polymer separator (4) has porosity and permeability. The materials of the membrane or polymer separator (4) include polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), nylon, cellulose and composite materials thereof. The structural form of the membrane or polymer separator (4) includes a mesh, a microporous film, a fabric or a multilayer composite structure of the mesh, microporous film and fabric. When the electrolyte solution flows through the interior of the three-dimensional electrode module (2), the external power supply (10) supplies power to the three-dimensional electrode module (2) and the counter electrode module (3), and ions in the electrolyte solution can pass through the diaphragm or polymer separator (4) and move between the three-dimensional electrode module (2) and the counter electrode module (3), forming an electrical circuit.

2. A three-dimensional electrochemical reactor according to claim 1, characterized in that: The three-dimensional electrochemical reactor is further provided with an electrode polarity conversion system (6), wherein the electrode polarity conversion system (6) is electrically connected to the external power supply (10) and the three-dimensional electrode module (2) and the counter electrode module (3), respectively. The electrode polarity conversion system (6) is used to switch the electrode polarity of the external power supply (10) supplying power to the three-dimensional electrode module (2) and the counter electrode module (3), thereby achieving selective control of oxidation reactions and reduction reactions on the three-dimensional electrode.

3. A three-dimensional electrochemical reactor according to claim 2, characterized in that: The polarity conversion frequency range of the electrode polarity conversion system (6) is 10 -6 Hz to 10 6 Hz.

4. A three-dimensional electrochemical reactor according to claim 2, characterized in that: The three-dimensional electrochemical reactor is further provided with a modular series-parallel interface (7) for connecting a plurality of reactor units to achieve series or parallel operation and control the liquid flow through the fluid inlet and outlet (8); the modular series-parallel interface (7) includes: a regulating valve, a proportional control valve, and a peristaltic pump.

5. A three-dimensional electrochemical reactor according to claim 4, characterized in that: The three-dimensional electrochemical reactor is further provided with a fluid control unit (9) and a control system (11); the fluid control unit (9) is connected to the fluid inlet of the first-stage reactor unit and is used to transport the electrolyte solution to the fluid inlet; the control system (11) is electrically connected to the fluid control unit (9) and the electrode polarity conversion system (6) and is used to control the transport flow of the fluid control unit (9) and the electrode polarity conversion of the electrode polarity conversion system (6); The modular serial-parallel interface (7) is used for subsequent flow control and diversion control.

6. The three-dimensional electrochemical reactor according to claim 1, characterized in that: The three-dimensional electrochemical reactor can be operated in a single-stage mode, or a multi-stage electrochemical reaction system can be formed by connecting multiple reactor units in series or in parallel; In the single-stage electrochemical reaction system, the electrolyte solution that has passed through the reactor is directed to the fluid storage unit (12) for storage, and then circulated and transported to the fluid inlet of the single-stage reactor again, thereby realizing a cyclic electrochemical reaction process; In the multi-stage electrochemical reaction system, the electrolyte solution from the upper-stage unit or the external fluid source is directed to the three-dimensional electrode module (2) of the lower-stage unit through the modular series-parallel interface (7) to serve as the input electrolyte solution for the electrochemical reaction of the next stage.

7. The three-dimensional electrochemical reactor according to claim 1, characterized in that: One of the electrodes arranged in pairs in the counter electrode module (3) is an inert clamping plate, and the other of the electrodes arranged in pairs is connected to an external power source (10) and used as a counter electrode.

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