Three-dimensional electrochemical reactor

Abstract

The invention belongs to the technical field of electrochemical engineering, and relates to a three-dimensional electrochemical reactor which comprises a reactor shell assembly, three-dimensional electrode modules, counter electrode modules, diaphragms or polymer partition plates and an external power supply, the counter electrode modules are arranged in pairs, and the three-dimensional electrode modules are clamped between the counter electrode modules arranged in pairs; the diaphragm or the polymer partition plate 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 and the diaphragm or the polymer partition plate are arranged in an inner cavity of the reactor shell assembly; according to the invention, the fluid can flow through the interior and surface of the three-dimensional electrode, and a main electrochemical reaction field is transferred to the interior and surface of the three-dimensional electrode, so that the sufficient flow and mixing of the fluid between the electrodes are ensured while the electrode spacing is shortened as far as possible, the solution resistance is reduced, the cell voltage is reduced, and the current efficiency is improved; and energy consumption increase and equipment damage caused by overhigh voltage are avoided.

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] Batch electrolysis is one of the most common types of electrochemical reactors, where reactants react in a fixed volume of solution until preset conditions, such as a preset reaction time, are reached. However, this type of reactor has some limitations: For example, since the concentration of reactants decreases over time during the reaction, it may lead to mass transfer limitations, thereby reducing the reaction rate and current efficiency.

[0004] The flow electrolysis cell controls the constant flow rate to make the reactants continue to pass through the reactor, ensuring that the reactants flow evenly on the electrode surface, thereby improving the uniformity of the reaction, operational continuity and efficiency. Although the flow electrolysis cell has operational continuity and efficient mass transfer performance, it also has the following limitations in practical applications: 1) Efficiency problems under low conductivity conditions: Under low conductivity conditions, the current efficiency of the flow electrolysis cell is usually low because the ion concentration is insufficient and the charge transfer capacity is limited, thereby reducing the electrochemical reaction rate. 2) Fluid uneven distribution problem: The flow electrolysis cell has high requirements for fluid distribution. Uneven fluid distribution can easily lead to insufficient local reactions or accumulation of reactants, thereby affecting the overall reaction effect and reducing mass transfer efficiency. 3) Interference with side reactions on the electrode: In the flow electrolysis cell, in addition to the main reaction on the working electrode, unnecessary side reactions may occur on the counter electrode. These side reactions interfere with the main reaction, reduce reaction efficiency, and affect the selectivity and purity of the product in electrochemical synthesis applications. Although the occurrence of side reactions can be reduced by selecting specific electrode materials or optimizing operating conditions, it is very difficult to completely avoid these reactions in complex chemical systems.

[0005] To overcome these problems, the existing technology has proposed some improvement measures. For example, using three-dimensional electrode materials with high specific surface area (such as carbon felt, graphite felt, carbon fiber, etc.) to increase the contact area between reactants and electrodes, thereby improving mass transfer efficiency and reaction rate; optimizing fluid mechanics design and rationally designing flow channel structure to achieve more uniform fluid distribution; or using selective electrode materials and various ion exchange membranes to reduce unnecessary side reactions.

[0006] However, these methods of the prior art still have the following deficiencies: Electrochemical reactors are difficult to operate under low conductivity conditions: When treating water bodies with low conductivity (such as tap water, agricultural water, animal husbandry water, industrial circulating water, chemical reaction water, etc.), the solution resistance will increase significantly, resulting in an increase in the cell voltage and a significant increase in energy consumption, thereby affecting the overall efficiency of the reactor. At the same time, under low conductivity conditions, electrode polarization is likely to intensify and local current density is uneven, further weakening the electrode activity.

[0007] Side reactions on the counter electrode are difficult to inhibit, 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 optimized operating conditions, complete inhibition is still difficult in complex chemical systems. The use of diaphragms (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 diaphragm material may also increase the resistance of the system, further reducing its applicability under low conductivity conditions.

[0008] High energy consumption and poor economy: In a low conductivity environment, in order to achieve the desired reaction effect, it is usually necessary to increase the voltage or current, which will significantly increase energy consumption, reduce economic benefits, and may bring safety hazards, such as electrode damage and dissolution of heavy metal ions (especially ruthenium iridium titanium electrodes and lead dioxide electrodes). In large-scale industrial applications, high energy consumption and high costs further limit the widespread application of existing electrochemical reactors.

[0009] Therefore, there is an urgent need for a device or method suitable for low-conductivity fluids that can effectively suppress side reactions on the counter electrode, thereby improving the overall reaction efficiency. At the same time, avoiding the use of complex reaction devices 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 a plurality of reactor units, the plurality of 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 a polymer partition, an external power supply, the inner cavity of the reactor housing assembly is used to accommodate the electrode module as the core and related accessories, the electrolyte solution can be a single liquid or a gas-liquid mixture, the electrolyte solution almost all passes through the inside of the three-dimensional electrode and reacts, the housing only plays a protective role, and its inner wall does not even need to be soaked by the 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 demand during operation, the three-dimensional electrode module serves as both an electrode and the inside 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, and limit 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 plays a role in hindering 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 to react while flowing through the three-dimensional electrode with a large area for electrochemical reaction;

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

[0013] The reactor housing assembly is provided with fluid inlets and outlets at the upper and lower ends, wherein the inlet at the upper end guides the electrolyte solution to the interior of the three-dimensional electrode through a flow guide pipe, and the flow guide pipe at the outlet at the lower end 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, 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 transfer of ions between electrodes under the premise of hindering convection. The material of the diaphragm or polymer separator can be selected from polymer materials with chemical stability, including: polyethylene PE, polypropylene PP, polytetrafluoroethylene PTFE, nylon, cellulose and composite materials thereof. The structural form of the diaphragm or polymer separator includes: mesh, microporous film, fabric or 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 source 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 to improve the utilization efficiency of the electrode and the selectivity of the reaction products.

[0018] Preferably, the three-dimensional electrochemical reactor is also provided with an electrode polarity conversion system, which electrically connects the external power supply to the three-dimensional electrode module and the counter electrode module respectively, and 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 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 needs 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 also provided with a modular series-parallel interface for connecting multiple 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 a quick connector, a plug-in interface, a bolt / nut fixing interface, etc., to meet different flow regulation requirements, and the modules can be directly connected or indirectly connected through a pipeline. 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 accurate control of the fluid flow between different modules, optimize the reaction efficiency of each module, and use a flow regulator (such as a peristaltic pump) with an active liquid delivery function, The system can achieve 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 unidirectionally 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 a plurality of 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 and transported to the fluid inlet of the single-stage reactor again, thereby realizing a cyclic electrochemical reaction process.

[0024] In a multi-stage electrochemical reaction system, the electrolyte solution from the previous unit or an 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 next stage of electrochemical reaction.

[0025] Preferably, one of the paired electrodes in the 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, the electrode spacing is reasonably shortened, so that 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 the solution resistance, reduces the cell voltage, improves the current efficiency, and avoids the increase in energy consumption and equipment damage caused by excessive voltage.

[0028] 2. The present invention introduces a polymer partition to inhibit 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 and 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 a three-dimensional electrode material with a 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 economy; 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 economy 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 modular design, and multiple three-dimensional electrode modules and supporting components can be combined and superimposed 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, and exhibits excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of equipment connection of a three-dimensional electrochemical reactor of 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 diagram between the present invention and a conventional 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 showing 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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the relevant technologies in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are 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 component 1, a three-dimensional electrode module 2, a counter electrode module 3, a diaphragm or polymer partition 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 housing, a shell and a reaction chamber, and has corrosion resistance, insulation and appropriate mechanical strength. In addition, the reactor housing 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 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 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 substances 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 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 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 can be stacked or composited with 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 loop by metal clamps, screw fixation, welding, plug-in terminals, crimping connections, etc. according to specific needs. Its material should be made of 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 by insulating corrosion-resistant materials (such as silicone-based glue, silicone rubber, polyethylene or polyvinyl chloride). Gold-plated connectors can also be selected as materials 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 high current. The system can realize the timing or conditional conversion of the electrode polarity through manual or automatic control (such as PLC or timer), and the operating frequency range is 10 -6 Hz to 10 6Hz. In a reversal cycle, the time the current remains in a certain direction can be adjusted arbitrarily between 0% and 100% according to demand. The system can be equipped with filters, overcurrent protection devices, varistors, etc. to ensure the stability of voltage and current. The functions of electrode polarity conversion include: flexible adjustment of electrode working polarity, control of oxidation / reduction reaction type; promotion of self-cleaning of electrode surface, prevention of passivation and polarization effects; control of reaction selectivity, and more precise product control.

[0046] Further, the modular serial-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 precise 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 the fluid discharged from the previous unit or the external fluid source (such as a liquid storage tank, a liquid supply system), and accurately guide the fluid to the three-dimensional electrode of the next module as the starting point of the new stage of electrochemical reaction. By adjusting the scale of a single reactor, such as the length and related structure of the three-dimensional electrode module, the order of the reaction 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 the fluid discharged from the previous unit or the fluid storage unit 12 (such as a liquid storage tank, a liquid supply system), and accurately guide the fluid to the three-dimensional electrode of the next module or the fluid storage unit 12 as the starting point of the electrochemical reaction, as the starting point of a new electrochemical reaction, thereby guiding the electrochemical reaction in the module to proceed smoothly. By adjusting the scale of a single reactor, such as the length of the three-dimensional electrode module and the supporting related structures, the order of the reaction can be flexibly controlled, where the reaction order n is a natural number ≥1.

[0049] Further, the fluid control unit 9 is designed to drive the fluid from the fluid storage unit 12 or the previous reactor unit to the specified position, ensuring that the fluid can be stably and accurately delivered to the three-dimensional electrode or other areas of the next-level module. The fluid control unit 9 can control the fluid transmission between different modules by adjusting the flow rate, pressure or delivery method according to system requirements. The process can be achieved by a peristaltic pump, a gas-liquid mixing pump, a diaphragm pump, a screw pump, a gas-liquid booster pump, a fluid control valve and the like, preferably a peristaltic pump.

[0050] Further, 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, and ensure 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, which is convenient for monitoring and debugging, and is used to calculate system performance indicators (such as energy consumption and current efficiency).

[0051] Furthermore, the control system 11 is the core management unit of the entire three-dimensional electrochemical reactor, responsible for the precise control and coordination of various modules such as fluid, reaction conditions and power supply. 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 system (SCADA) and a PLC or DCS, preferably a programmable logic controller.

[0052] Furthermore, a plurality of fluid storage units 12 are provided for storing fluids to be processed, being processed or after being processed. The fluid storage unit 12 is connected to the fluid control unit 9 through a pipeline to achieve a stable fluid supply and circulation to the reactor unit, thereby ensuring the continuous and stable operation of the electrochemical reaction. In addition, by changing the pipeline connection mode, it is also possible to make the fluid pass through multiple stages of series-connected reactor units continuously at one time and complete the reaction in real time, or to make the fluid pass through a single-stage or multi-stage reactor repeatedly and complete the reaction within 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 pipelines and bypass systems, quick connectors and valves.

[0054] Example

[0055] Example 1: In order to simulate the actual working conditions of low conductivity water, this example uses sodium sulfate as the supporting electrolyte and adjusts the conductivity of the fluid (deionized water) to 271 μS / cm. Under this condition, the working performance of the three-dimensional electrochemical reactor of the present invention and the traditional intermittent electrolytic cell are compared.

[0056] In the three-dimensional electrochemical reactor, G280A graphite felt electrode is used as the core of the three-dimensional electrode module; ruthenium iridium titanium electrode is used as the counter electrode; 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 20cm 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 will occur 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 uses 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 is also 20 cm 2 Under the condition of , the programmable power supply was used to apply 5.00V, 7.50V and 10.0V voltages for testing, and the test results were obtained after the system stabilized for 1 minute. The results show that under the above different voltage gradients, the corresponding currents are only 0.0467A, 0.0538A and 0.0806A (such as 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 0.4A). This indicates 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 3 As shown in e.

[0058] Example 2: Using the same experimental conditions as Example 1 (current density of 20 mA / cm 2 , the three-dimensional electrode projection area is 20cm 2 ) is used to test a low conductivity phenolic water sample, wherein phenols are used as indicators of electrochemical oxidation reactions to evaluate the effect of the reaction. This embodiment controls the dominant direction of the reaction by adjusting the polarity of the three-dimensional electrode, which are electrochemical oxidation (EO, in which case the three-dimensional electrode is the anode) and electrochemical reduction (ER, in which case the three-dimensional electrode is the cathode). Figure 4 As shown, Figure 4 a and Figure 4 The only difference between the experiment in b is the control of the electrode polarity. Figure 4 In a, the three-dimensional electrode is used as the anode. After passing through the two-stage series reactor, the phenolic water sample shows a distinct black color, indicating that quinones have been formed. This shows that under the electrochemical oxidation conditions, after a short reaction stage (only two-stage reactors), phenols are rapidly oxidized to generate quinones.

[0059] In contrast, Figure 4b shows the experimental results when the three-dimensional electrode is the cathode. Under the same current density conditions, although the phenol-containing water sample has been treated with more four-stage series reactors, the solution remains clear and transparent, and no visible black change occurs. This indicates that in the reaction dominated by electrochemical reduction (ER), phenolic substances are not oxidized, the formation of quinone substances is almost completely suppressed, and the electrochemical oxidation reaction is effectively isolated in this system.

[0060] The above experimental comparison shows that the polarity of the three-dimensional electrode plays a crucial role in the dominant role of the reaction and can be effectively controlled. When the three-dimensional electrode is used as the anode, the electrochemical oxidation (EO) reaction is dominant; when the three-dimensional electrode is used 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, and the removal rate at different time points is calculated based on the highest absorbance at 266 nm. Figure 5 It can be seen that the removal rate of ciprofloxacin increased significantly with the 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 the highest value of 97.77%. This result shows that the removal efficiency of ciprofloxacin in low conductivity water bodies increases significantly over time, especially in the first 6 hours (reaching 87.04%, close to 90% removal rate), and then stabilizes.

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

[0063]

[0064] Table 1

[0065] Table 1 shows the changes in key result parameters of the present invention in the process of treating 1000 μg of ciprofloxacin. After 0.5 hours of reaction, the removal rate reached 77.4%; after 2 hours of reaction, the removal rate further increased to 98.1%; after 3 hours and 4 hours of reaction, the removal rate reached 99.6%, indicating that the removal effect was close to complete. This experimental result shows that under this reaction condition, the removal efficiency of ciprofloxacin increased rapidly within the first 2 hours, and tended to stabilize in the subsequent time period, achieving a nearly complete removal effect, reflecting the efficiency and applicability of this method in simulating the treatment of actual polluted water bodies.

[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 the processing requirements, thereby enhancing the processing capacity and operational flexibility of the system. By optimizing the reactor structure, the electrode spacing is reasonably shortened, so that 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, the full flow and mixing of the fluid between the electrodes is ensured, the solution resistance is reduced, the tank voltage is reduced, the current efficiency is improved, and the energy consumption increase and equipment damage caused by excessive voltage are avoided. In addition, the present invention uses a cheap and readily available polymer partition as a separating medium, and 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, wide application range, etc. 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 a polymer separator (4), and an external power source (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 the interior of the three-dimensional electrode module (2) also serves as a channel for the flow of 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 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, the counter electrode modules (3) arranged in pairs clamp the three-dimensional electrode module (2) in the middle, 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 respectively electrically connected to the positive and negative electrodes of the external power source (10); 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, and the flow guide pipe at the outlet at the lower end 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, or 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 metal, titanium-based alloy, graphite, and precious metal oxide; 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 inside of the three-dimensional electrode module (2), the external power source (10) supplies power to the three-dimensional electrode module (2) and the counter electrode module (3), and the 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 source (10) and the three-dimensional electrode module (2) and the counter electrode module (3), respectively, and the electrode polarity conversion system (6) is used to switch the electrode polarity of the external power source (10) supplying power to the three-dimensional electrode module (2) and the counter electrode module (3), thereby realizing 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 also 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 also 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 flow diversion control.

6. A 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 can be combined into a multi-stage electrochemical reaction system 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 previous unit or the external fluid source is directed to the three-dimensional electrode module (2) of the next unit through the modular series-parallel interface (7) to serve as the input electrolyte solution for the next stage of electrochemical reaction.

7. A 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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