A novel three-dimensional particle electrode electro-catalytic oxidation device

Abstract

The application discloses a novel three-dimensional particle electrode electro-catalytic oxidation device, which comprises a three-dimensional electro-catalytic shell, a three-dimensional electro-catalytic system, a particle electrode cleaning system and a supporting layer arranged in the three-dimensional electro-catalytic shell; the three-dimensional electro-catalytic system comprises an anode, a cathode, a particle electrode and a partition plate; the anode and the cathode are connected with an anode and a cathode of an external rectifier respectively; the particle electrode is a carbon-based material loaded with metal oxides; the partition plate divides the particle electrode into an anode area, a cathode area and an intermediate area; the particle electrode cleaning system comprises a backwashing fan and a gas distribution pipe; the backwashing fan provides power for particle electrode flow; the gas distribution pipe is connected with the backwashing fan; and the supporting layer is composed of a supporting plate and graded particles.

Description

Technical Field

[0001] This application belongs to the field of wastewater treatment, and in particular relates to a novel three-dimensional particle electrode electrocatalytic oxidation device. Background Technology

[0002] With the development of modern industry, the volume and composition of industrial wastewater discharge are increasing daily, and the treatment of industrial wastewater containing recalcitrant organic pollutants has always been a challenging problem. Electrocatalytic oxidation technology is a technique that promotes the oxidative decomposition of organic matter through oxidation on the electrode surface or through the action of free radicals generated by an electric field. Recently, the method of treating recalcitrant organic wastewater using electrocatalytic oxidation technology has gradually attracted attention. Electrocatalytic oxidation technology can degrade organic matter in wastewater more thoroughly, is less likely to produce toxic intermediate products, requires no subsequent treatment, and has a particularly good effect on removing recalcitrant pollutants. However, traditional two-dimensional flat electrodes have a small surface area, low unit tank capacity, and low current efficiency, especially at low conductivity, thus making it difficult to achieve breakthroughs in practice. Compared with two-dimensional electrodes, three-dimensional electrodes have an increased surface area and smaller particle spacing, improving mass transfer, thus exhibiting higher current efficiency and unit space-time yield. Furthermore, three-dimensional electrodes have a small footprint, large processing capacity, convenient management, are easy to implement continuous operation, and can operate at different current densities.

[0003] This article describes an improved electrolytic oxidation technology—three-dimensional particle electrode electrolytic catalytic oxidation technology. This technology involves filling the space between the anode and cathode with granular or other particulate working electrode materials. When the main electrode comes into contact with the conductive particles, the particles have the same electrode potential as the main electrode, meaning the particles also become part of the main electrode. This significantly expands the surface area of ​​the anode or cathode. Compared to two-dimensional electrocatalysis, this technology increases the throughput per unit tank and improves current efficiency.

[0004] Chinese patent CN 214192881U discloses a particle electrode wastewater treatment device, comprising two particle electrode adsorption and filtration systems and an adsorbent regeneration system. The particle electrode adsorption and filtration system includes an inlet pump, a particle electrode adsorption tank, and a filtration device connected sequentially via pipelines. Each particle electrode adsorption tank contains a particle electrode, and the filtration device has a treated water outlet and a particle electrode outlet. The adsorbent regeneration system includes a pressure pump, a dissolved oxygen tank, and a three-dimensional electrolytic cell connected sequentially via pipelines. The inlet of the pressure pump is connected to the two particle electrode outlets via pipelines, and an oxygen inlet pipe is connected to the inlet of the pressure pump. The outlet of the three-dimensional electrolytic cell is connected to the two ion electrode adsorption tanks via pipelines, and valves are installed on all pipelines. This increases the number of hydroxyl radicals, reduces the distance between the particle electrodes and pollutants, and the two particle electrode adsorption and filtration systems adsorb pollutants alternately, improving wastewater treatment efficiency. Existing patents describe filled particle electrodes, but this patent requires two systems—an adsorption and filtration system and an adsorbent regeneration system.

[0005] Chinese patent CN 104085959A discloses a three-dimensional electrocatalytic oxidation reactor with expanded cathode or anode. The device consists of a reactor shell, cathode and anode plates, particle electrodes, insulating particles, and aeration pipes. This device expands the anode or cathode using particle electrodes made of the same material as the electrode plates, and isolates them from the other electrode using insulating particles. By expanding the cathode or anode, the oxidation and reduction zones of the three-dimensional electrocatalytic oxidation reactor are purposefully enlarged, allowing for more targeted wastewater treatment. Existing patents describe particle electrodes made of the same material as the electrode plates, using insulating particles to separate the anode and cathode regions, and assisting the aeration process during the three-dimensional electrocatalytic process to remove pollutants from the wastewater. However, the lack of a separator or other material between the insulating particles and the particle electrodes makes installation difficult; furthermore, aeration disturbances during operation can easily cause the insulating particles to mix with the particle electrodes, rendering the particle electrodes ineffective as described in the patent.

[0006] Chinese patent CN205328672U discloses a cylindrical three-dimensional particle electrode reactor with annular grooves and a particle electrode filling method. The aim is to provide a cylindrical three-dimensional particle electrode reactor that can effectively reduce short-circuit current and ensure uniform distribution of the generated oxidizing active substances. The reactor is cylindrical in shape and consists of a main electrode anode, an outer annular groove, a middle annular groove, an inner annular groove, a main electrode cathode, an overflow pipe, a water inlet pipe, a porous support plate, and particle electrodes. Multiple and micropores are formed on the walls of all annular grooves, which are filled with particle electrodes. There is a certain spacing between the annular grooves, which effectively separates the particle electrodes, reduces short-circuit current, ensures uniform distribution of the generated oxidizing active substances, improves reaction efficiency, and saves particle electrodes. Existing patents describe cylindrical three-dimensional particle electrode reactors with annular grooves and a particle electrode filling method. The annular groove walls have multiple and micropores filled with particle electrodes; simultaneously, there is a certain spacing between the annular grooves. This results in the high processing difficulty of the three-dimensional particle electrode reactor described in the patent, making it difficult to scale up the equipment and produce complete sets.

[0007] Chinese patent CN 101781002B discloses an extended anode electrolytic cyanide-degrading wastewater treatment device, comprising: a shell, a cathode plate, an anode plate, particle electrodes filled between the cathode and anode plates, a DC power supply connected to the cathode and anode plates, and an inlet tank, an inlet hole, an outlet hole, an outlet tank, a drain pipe, an aeration pipe, and a sludge discharge port. The improvement lies in that the cathode plate and anode plate are vertically and parallelly fixed within the shell. The surface of the cathode plate is covered with an insulating layer. The particle electrodes are made of the same material as the anode plate, forming an extended anode together. The internal plates isolate several independent reaction chambers. Wastewater is evenly distributed through the inlet tank and flows upward through the reactor from the lower inlet hole of each reaction chamber, exiting from the upper outlet hole and collecting in the outlet tank. Because each reaction chamber is filled with particles of the same material as the anode, the anode area is expanded, improving mass transfer and reaction efficiency, thus enabling efficient degradation of cyanide in the wastewater. The existing patent describes an extended anode electrolytic cyanide-breaking wastewater treatment device, which uses graphite as the anode and graphite particles as particle electrodes to form an extended anode in contact with the anode; the cathode surface has an insulating mesh to separate the anode and cathode; the patent has a simple structure, selects a simple graphite electrode as the anode, and the graphite particle electrodes only fill the anode area, and only treats cyanide-containing wastewater. Summary of the Invention

[0008] The technical problem to be solved by this application is that the two-dimensional flat electrode has a small surface area, low unit tank capacity, and low current efficiency, especially at low conductivity, which makes it difficult to make breakthrough progress in practice. This application provides a novel three-dimensional particle electrode electrocatalytic oxidation device that can effectively degrade recalcitrant organic matter in industrial wastewater, thereby reducing the burden on subsequent treatment systems.

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

[0010] A novel three-dimensional particle electrode electrocatalytic oxidation device includes a three-dimensional electrocatalytic shell, wherein a three-dimensional electrocatalytic system, a support layer and a particle electrode cleaning system are arranged from top to bottom inside the three-dimensional electrocatalytic shell.

[0011] The three-dimensional electrocatalytic system includes graded granules, a cathode, an anode, a rectifier, and partitions. The rectifier can switch between constant voltage and constant current modes. The anode and cathode are arranged parallel to each other on the inner walls of opposite sides of the three-dimensional electrocatalytic shell. The graded granules are located at the bottom of the three-dimensional electrocatalytic system. The anode and cathode are connected to the positive and negative terminals of the rectifier, respectively. Particle electrodes are filled between the anode, cathode, and graded granules. Two vertical partitions inside the three-dimensional electrocatalytic system divide the particle electrodes into an anode region, a cathode region, and an intermediate region. The particle electrodes in the anode region are connected to the anode, and the particle electrodes in the cathode region are connected to the cathode.

[0012] The support layer is a uniformly distributed plate, which is located at the bottom of the graded granules.

[0013] The particle electrode cleaning system consists of a backwash fan, a water inlet pump, an air distribution pipe, and a water inlet. The air distribution pipe is located below the three-dimensional electrocatalytic system. A backwash fan connected to the air distribution pipe is located on one side of the bottom of the three-dimensional particle electrode electrocatalytic oxidation device, and a water inlet is located on the other side of the bottom of the three-dimensional particle electrode electrocatalytic oxidation device. The water inlet is connected to the water inlet pump.

[0014] The three-dimensional electrocatalytic shell has a water outlet on one side of the top.

[0015] Furthermore: the anode is a plate-shaped electrode, specifically a graphite electrode, a dimensionally stable anode (DSA), or a lead anode; the cathode is a plate-shaped electrode, specifically a graphite electrode, a carbon steel electrode, or a stainless steel electrode; the anode and cathode can directly oxidize or reduce pollutants in the recalcitrant wastewater on the electrode surface.

[0016] Furthermore, the particle electrode filled in the three-dimensional electrocatalytic system is a porous catalyst particle, which is composed of metal oxides loaded on a carbon substrate; the carbon substrate is granular carbon, columnar carbon or powdered carbon processed into shape; the metal oxide is titanium oxide, tin-antimony oxide or noble metal oxide.

[0017] Furthermore, the surface of the separator is uniformly covered with micropores, the pore diameter of which is smaller than the maximum diameter of the particle electrode. The separator is made of a non-conductive material, specifically PP or PTFE.

[0018] Furthermore, a flow guide net is provided between the particle electrodes in the intermediate zone to facilitate the uniform flow of wastewater between the particle electrodes.

[0019] Further: The particle electrode cleaning system is powered by a backwash fan, which can be a centrifugal fan or an axial fan; the air distribution pipe is a perforated perforated pipe.

[0020] Furthermore, the particle electrode in the anode region is connected to the anode and serves as an extension of the anode. The particle electrode in the anode region exhibits oxidizing properties and can oxidize and degrade wastewater passing through the surface of the particle electrode in the anode region.

[0021] Furthermore, the particle electrode in the cathode region is connected to the cathode, serving as an extension of the cathode and increasing the actual area of ​​the cathode; the particle electrode in the cathode region exhibits reducing properties, which can reduce pollutants in the wastewater flowing through the cathode region and reduce the toxicity of the pollutants.

[0022] Furthermore, the particle electrodes in the intermediate zone are not connected to the anode and cathode due to the action of the partition. They become bipolar particle electrodes by utilizing the electric field induction generated between the energized anode and cathode. Anode and cathode are generated at both ends of the particles to oxidize and reduce pollutants in the wastewater, thereby achieving the ring-opening and chain-breaking effect of pollutants in the wastewater and improving the biodegradability of the wastewater.

[0023] Furthermore, during the three-dimensional electrocatalysis process, the particle electrodes may be damaged or worn out. After damage, the fine carbon-based materials can easily clog the channels between the particle electrodes, preventing the free flow of wastewater in the three-dimensional electrocatalysis device. When this happens, a backwashing fan is used to provide backwashing power. When air enters the particle electrode area through the water distribution pipe and the graded granules, the particle electrodes flow, thereby flushing out the broken and fine carbon-based materials from the outlet at the top of the three-dimensional electrocatalysis device, so as to maintain the continuous and stable operation of the three-dimensional electrocatalysis process.

[0024] Compared with the prior art, the technical solution adopted in this application has the following technical effects:

[0025] 1. Compared with plate electrodes, particle electrodes have a larger specific surface area. In the cathode and anode regions, particle electrodes can serve as extensions of the cathode and anode, increasing the surface area of ​​the electrodes actually participating in the reaction and improving electrolysis efficiency.

[0026] 2. The particle electrode in the middle region has bipolarity under the action of an electric field. The two ends of the particle electrode particles have the characteristics of cathode and anode, respectively. Each particle electrode particle becomes an independent electrolytic oxidation / reduction reaction unit. Compared with traditional plate electrodes, it greatly increases the electrode area of ​​the effective electrolytic reaction and improves the reaction efficiency.

[0027] 3. Porous catalyst particles can be used for particle electrodes, which can effectively improve the oxidation effect of pollutants in wastewater.

[0028] 4. Impurities accumulated between the particle electrodes can be removed through the backwashing system, which is beneficial to the continuous and stable operation of the three-dimensional electrocatalytic device;

[0029] 5. It has a fast mass transfer rate, increases the conductivity of wastewater, has high current efficiency and low energy consumption, and can be used for wastewater with low conductivity. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of this application.

[0031] In the diagram, 1. Backwash fan; 2. Inlet pump; 3. Air distribution pipe; 4. Outlet; 5. Graded granules; 6. Cathode zone; 7. Anode zone; 8. Intermediate zone; 9. Cathode; 10. Anode; 11. Rectifier; 12. Inlet; 13. Baffle; 14. Distribution plate. Detailed Implementation

[0032] The technical solution of this application will be further described in detail below with reference to the accompanying drawings:

[0033] like Figure 1 As shown, a novel three-dimensional particle electrode electrocatalytic oxidation device includes a three-dimensional electrocatalytic shell, in which a three-dimensional electrocatalytic system, a support layer, and a particle electrode cleaning system are arranged from top to bottom.

[0034] The three-dimensional electrocatalytic system includes graded granules 5, a cathode 9, an anode 10, a rectifier 11, and a partition 13. The rectifier 11 can switch between constant voltage and constant current modes. The anode 10 and cathode 9 are respectively arranged parallel to each other on the inner walls of opposite sides of the three-dimensional electrocatalytic shell. The graded granules 5 are located at the bottom of the three-dimensional electrocatalytic system. The anode 10 and cathode 9 are respectively connected to the positive and negative terminals of the rectifier 11. Particle electrodes are filled between the anode 10, cathode 9, and graded granules 5. Two vertical partitions 13 inside the three-dimensional electrocatalytic system divide the particle electrodes into an anode region 7, a cathode region 6, and an intermediate region 8. The particle electrodes in the anode region 7 are connected to the anode 10, and the particle electrodes in the cathode region 6 are connected to the cathode 9.

[0035] The support layer is a uniformly distributed plate 14, which is disposed at the bottom of the graded granules 5.

[0036] The particle electrode cleaning system consists of a backwash fan 1, a water pump 2, an air distribution pipe 3, and a water inlet 12. The air distribution pipe 3 is located below the three-dimensional electrocatalytic system. The backwash fan 1, which is connected to the air distribution pipe 3, is located on one side of the bottom of the three-dimensional particle electrode electrocatalytic oxidation device. The water inlet 12 is located on the other side of the bottom of the three-dimensional particle electrode electrocatalytic oxidation device. The water inlet 12 is connected to the water pump 2.

[0037] The three-dimensional electrocatalytic shell has a water outlet 4 on one side of the top.

[0038] The anode 10 is a plate-shaped electrode, specifically a graphite electrode, a dimensionally stable anode (DSA), or a lead anode; the cathode 9 is a plate-shaped electrode, specifically a graphite electrode, a carbon steel electrode, or a stainless steel electrode; the anode 10 and the cathode 9 can directly oxidize or reduce pollutants in the wastewater that are difficult to degrade on the electrode surface.

[0039] The particle electrode filled in the three-dimensional electrocatalytic system is a porous catalyst particle, which is composed of metal oxides loaded on a carbon substrate; the carbon substrate is granular carbon, columnar carbon or powder carbon processed into shape; the metal oxide is titanium oxide, tin-antimony oxide or noble metal oxide.

[0040] The surface of the partition 13 is uniformly covered with micropores, the pore diameter of which is smaller than the maximum diameter of the particle electrode. The partition 13 is made of non-conductive material, specifically PP or PTFE.

[0041] A flow guide net is provided between the particle electrodes in the intermediate zone 8 to facilitate the uniform flow of wastewater between the particle electrodes.

[0042] The particle electrode cleaning system is powered by a backwash fan 1, which is either a centrifugal fan or an axial fan; the air distribution pipe 3 is a perforated perforated pipe.

[0043] The particle electrode in the anode region 7 is connected to the anode 10 and serves as an extension of the anode. The particle electrode in the anode region 7 exhibits oxidizing properties and can oxidize and degrade wastewater passing through the surface of the particle electrode in the anode region 7.

[0044] The particle electrode in the cathode region 6 is connected to the cathode 9, serving as an extension of the cathode and increasing the actual area of ​​the cathode. The particle electrode in the cathode region 6 exhibits reducing properties, which can reduce pollutants in the wastewater flowing through the cathode region 6 and reduce the toxicity of the pollutants.

[0045] The particle electrode in the intermediate zone 8 is not connected to the anode 10 and cathode 9 due to the action of the partition 13. It becomes a bipolar particle electrode by utilizing the electric field induction generated between the energized anode and cathode. It generates anode and cathode at both ends of the particle to oxidize and reduce pollutants in the wastewater, realize the opening and breaking of the chain of pollutants in the wastewater, and improve the biodegradability of the wastewater.

[0046] During the three-dimensional electrocatalysis process, the particle electrodes may be damaged or worn out. After damage, the fine carbon-based materials can easily clog the channels between the particle electrodes, preventing the free flow of wastewater in the three-dimensional electrocatalysis device. When this happens, the backwashing fan 1 provides backwashing power. When air enters the particle electrode area through the water distribution pipe 3 and the graded granules 5, the particle electrodes flow, thereby flushing out the broken and fine carbon-based materials from the outlet 4 at the top of the three-dimensional electrocatalysis device, so as to maintain the continuous and stable operation of the three-dimensional electrocatalysis process.

[0047] The above embodiments are merely illustrative of the technical concept of this application and should not be construed as limiting the scope of protection of this application. Any modifications made to the technical solution based on the technical concept proposed in this application shall fall within the scope of protection of this application. The implementation methods of this application have been described in detail above, but this application is not limited to the above implementation methods. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A three-dimensional particle electrode electrocatalytic oxidation device, characterized in that: It includes a three-dimensional electrocatalytic shell, in which a three-dimensional electrocatalytic system, a support layer, and a particle electrode cleaning system are arranged from top to bottom; The three-dimensional electrocatalytic system includes graded granules (5), cathode (9), anode (10), rectifier (11), and partition (13). The rectifier (11) can switch between constant voltage and constant current modes. The anode (10) and cathode (9) are respectively arranged parallel to each other on the inner walls of opposite sides of the three-dimensional electrocatalytic shell. The graded granules (5) are arranged at the bottom of the three-dimensional electrocatalytic system. The anode (10) and cathode (9) are respectively connected to the positive and negative poles of the rectifier (11). The particle electrode fills the space enclosed by the anode (10), cathode (9), and graded granules (5). Two vertical partitions (13) are used to divide the enclosed space into an anode area (7), a cathode area (6), and an intermediate area (8). The particle electrode in the anode area (7) is connected to the anode (10), and the particle electrode in the cathode area (6) is connected to the cathode (9). The support layer is a uniformly distributed plate (14), which is located at the bottom of the graded granules (5); The particle electrode cleaning system consists of a backwash fan (1), a water pump (2), an air distribution pipe (3), and a water inlet (12). The air distribution pipe (3) is located below the three-dimensional electrocatalytic system. A backwash fan (1) connected to the air distribution pipe (3) is provided on one side of the bottom of the three-dimensional particle electrode electrocatalytic oxidation device. A water inlet (12) is provided on the other side of the bottom of the three-dimensional particle electrode electrocatalytic oxidation device. The water inlet (12) is connected to the water pump (2). The three-dimensional electrocatalytic shell has a water outlet (4) on one side top. The particle electrode in the anode region (7) is connected to the anode (10) and serves as the anode extension. The particle electrode in the anode region (7) exhibits oxidizing properties and can oxidize and degrade wastewater passing through the surface of the particle electrode in the anode region (7). The particle electrode in the cathode region (6) is connected to the cathode (9) and serves as an extension of the cathode, increasing the actual area of ​​the cathode. The particle electrode in the cathode region (6) exhibits reducing properties and can reduce pollutants in the wastewater flowing through the cathode region (6), thereby reducing the toxicity of the pollutants. The surface of the partition (13) is uniformly covered with micropores, the pore size of which is smaller than the maximum diameter of the particle electrode, and the partition (13) is made of non-conductive material; The particle electrode in the intermediate zone (8) is not connected to the anode (10) and cathode (9) due to the action of the partition (13). It becomes a bipolar particle electrode by utilizing the electric field generated between the energized anode and cathode. It generates anode and cathode at both ends of the particle to oxidize and reduce pollutants in the wastewater, realize the opening and breaking of the chain of pollutants in the wastewater, and improve the biodegradability of the wastewater. The particle electrode filled in the three-dimensional electrocatalytic system is a porous catalyst particle, which is composed of a metal oxide supported on a carbon-based material; the carbon-based material is granular carbon, columnar carbon or powdered carbon processed into shape; the metal oxide is titanium oxide, tin-antimony oxide or noble metal oxide. During the three-dimensional electrocatalysis process, the particle electrode may be damaged or lost. After damage, the fine carbon-based material is prone to block the channels between the particle electrodes, preventing the wastewater from flowing freely in the three-dimensional particle electrode electrocatalytic oxidation device. When this happens, the backwashing fan (1) provides backwashing power. When air enters the particle electrode area through the air distribution pipe (3) and the graded granules (5), it drives the particle electrode to flow, thereby flushing the broken fine carbon-based material out from the outlet (4) at the top of the three-dimensional particle electrode electrocatalytic oxidation device, so as to maintain the continuous and stable operation of the three-dimensional electrocatalytic process.

2. The three-dimensional particle electrode electrocatalytic oxidation device according to claim 1, characterized in that: The anode (10) is a plate electrode, which can be a graphite electrode, a size-stabilized anode, or a lead anode; the cathode (9) is a plate electrode, which can be a graphite electrode, a carbon steel electrode, or a stainless steel electrode; the anode (10) and the cathode (9) can directly oxidize or reduce pollutants in the wastewater that are difficult to degrade on the electrode surface.

3. The three-dimensional particle electrode electrocatalytic oxidation device according to claim 1, characterized in that: The partition (13) is made of PP or PTFE material.

4. The three-dimensional particle electrode electrocatalytic oxidation device according to claim 1, characterized in that: A flow guide net is provided between the particle electrodes in the intermediate zone (8) to facilitate the uniform flow of wastewater between the particle electrodes.

5. The three-dimensional particle electrode electrocatalytic oxidation device according to claim 1, characterized in that: The particle electrode cleaning system is powered by a backwash fan (1), which is either a centrifugal fan or an axial fan; the air distribution pipe (3) is a perforated pipe.

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