Three-dimensional electrodes, three-dimensional electrode reactors, wastewater treatment systems, and methods for electrochemical treatment of wastewater.

Abstract

This invention relates to the field of industrial wastewater treatment technology, and discloses a three-dimensional electrode, a three-dimensional electrode reactor, a wastewater treatment system, and a method for electrochemical treatment of wastewater. The three-dimensional electrode includes a cathode, an anode, and a particle electrode that fills the space between the cathode and the anode during use. The particle electrode is polyphenylene sulfide particles loaded with carbon fibers. The three-dimensional electrode, three-dimensional electrode reactor, wastewater treatment system, and wastewater electrochemical treatment method provided by this invention do not require the addition of chemical reagents, produce no secondary pollution, have low energy consumption, and achieve good treatment results.

Description

Technical Field

[0001] This invention relates to the field of industrial wastewater treatment technology, specifically to a three-dimensional electrode, a three-dimensional electrode reactor, a wastewater treatment system, and a method for electrochemical treatment of wastewater. Background Technology

[0002] With the rapid development of the industrial age and the increasing demands of industrial production, the problem of industrial wastewater is becoming increasingly serious, especially the treatment of wastewater with high salinity, nitrogen content, and recalcitrant organic matter. An effective, green, and economical technology is urgently needed. Electrochemical oxidation technology is a green and environmentally friendly technology that uses electrical energy to remove pollutants through electron transfer and the generation of hydroxyl radicals (·OH) on the electrode surface, resulting in a redox reaction. It is simple to operate, has mild reaction conditions, requires no chemical additives, and does not produce secondary pollution. Electrochemical technology can simultaneously treat TOC and total nitrogen in recalcitrant organic wastewater.

[0003] As a type of electrochemical oxidation system, the three-dimensional electrode system has advantages over the traditional two-dimensional electrode system, including a larger effective electrode area, a larger reactor surface-to-volume ratio, better mass transfer, and higher current efficiency. The reaction mechanism for pollutant removal in a three-dimensional electrode reactor is complex and varies depending on the properties of the wastewater being treated, the performance of the main electrode, and the electrocatalytic activity of the filling particle material. However, in existing three-dimensional electrode systems, the particle electrodes are mostly activated carbon loaded with functional components. During the reaction, activated carbon residue may detach, leading to problems such as polluting the effluent and the need for replenishment of the particle electrodes. Furthermore, some three-dimensional electrode systems require the installation of diaphragms, increasing economic costs and imposing certain requirements on the influent water quality, thus limiting their application. Summary of the Invention

[0004] The purpose of this invention is to overcome the aforementioned technical problems existing in the prior art, and to provide a three-dimensional electrode, a three-dimensional electrode reactor, a wastewater treatment system, and a method for electrochemical treatment of wastewater.

[0005] To achieve the above objectives, a first aspect of the present invention provides a three-dimensional electrode comprising a cathode, an anode, and a particle electrode that fills the space between the cathode and the anode during use, wherein the particle electrode is a polyphenylene sulfide particle loaded with carbon fibers.

[0006] A second aspect of the present invention provides a three-dimensional electrode reactor, the reactor comprising a water distributor, an electrode plate and a particle electrode, wherein the electrode plate comprises at least one cathode plate and at least one anode plate, and the cathode plate and the anode plate are spaced apart in the reactor to divide the reactor cavity into a plurality of parallel channels, the particle electrode being filled in each channel, the water distributor being disposed below the channels for supporting the particle electrode and distributing wastewater, and the particle electrode being polyphenylene sulfide particles loaded with carbon fibers.

[0007] A third aspect of the present invention provides a wastewater treatment system, which includes a storage tank, the three-dimensional electrode reactor described above, and a gas collection device connected in sequence.

[0008] The fourth aspect of the present invention provides a method for electrochemical treatment of wastewater, the method comprising: electrolyzing wastewater using the three-dimensional electrode described in the first aspect, the three-dimensional electrode reactor described in the second aspect, or the system described in the third aspect.

[0009] Through the above technical solution, the present invention achieves the following beneficial effects:

[0010] (1) Existing wastewater treatment processes usually require the addition of chemical agents (which introduce new ions into the wastewater), are complex to operate, have unsatisfactory treatment effects, and cannot stably meet emission standards. However, the three-dimensional electrode, three-dimensional electrode reactor, wastewater treatment system, and wastewater electrochemical treatment method provided by this invention do not require the addition of chemical agents, have no secondary pollution, low energy consumption, and good treatment effect.

[0011] (2) Existing particle electrodes (such as activated carbon) require regeneration after treating wastewater for a period of time. However, the three-dimensional electrode, three-dimensional electrode reactor, and wastewater treatment system provided by this invention use polyphenylene sulfide particles loaded with carbon fibers as particle electrodes, which have the advantages of high efficiency, no pollution, and in-situ regeneration. That is, the particle electrodes of this invention do not require separate regeneration; regeneration can be achieved during the wastewater treatment process. Furthermore, neither the three-dimensional electrode nor the three-dimensional electrode reactor of this invention requires a diaphragm, which reduces costs. Moreover, the three-dimensional electrode, three-dimensional electrode reactor, and wastewater treatment system of this invention can operate stably for a long period.

[0012] (3) The present invention can treat wastewater with high salt content, nitrogen content and recalcitrant organic matter, and can remove nitrogen and organic matter at the same time during the wastewater treatment process.

[0013] (4) The preferred embodiment of the present invention can use a gas collection device to process the gas generated during the reaction in a timely manner, so as to avoid reaching the explosion limit and causing danger. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a preferred wastewater treatment system according to the present invention.

[0015] Explanation of reference numerals in the attached figures

[0016] 1-Inlet pipe 2-Storage tank 3-Exhaust port 4-Pump 5-Water distributor 6-Electrode plate 7-Particle electrode 8-Overflow weir 9-Outlet pipe 10-Return pipe 11-Negative pressure exhaust pipe 12-Absorption tank 13-Blower exhaust pipe Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The first aspect of the present invention provides a three-dimensional electrode comprising a cathode, an anode, and a particle electrode which may be filled between the cathode and the anode during use, wherein the particle electrode is polyphenylene sulfide (PPS) particles loaded with carbon fibers.

[0019] The three-dimensional electrode can be sold separately as a cathode, anode, and particle electrode. However, during use, the cathode, anode, and particle electrode need to be assembled, with the particle electrode placed between the cathode and anode to form the three-dimensional electrode. In operation, the anode and cathode are connected to the positive and negative terminals of a power source, respectively. A voltage is applied to the anode and cathode, thereby degrading nitrogenous substances or organic matter in the wastewater.

[0020] According to the present invention, preferably, the carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 10-50% by weight (e.g., 10% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 50% by weight, and any two of the above), preferably 30-40% by weight.

[0021] According to the present invention, preferably, the length of the carbon fiber is 0.1-50 mm (e.g., 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, and any two of the above), preferably 1-4 mm.

[0022] According to the present invention, preferably, the average diameter of the polyphenylene sulfide particles loaded with carbon fibers is 0.1-2 cm (e.g., 0.1 cm, 0.2 cm, 0.3 cm, 0.4 cm, 0.5 cm, 0.6 cm, 0.7 cm, 1 cm, 1.5 cm, 2 cm, and any two of the above), preferably 0.2-0.5 cm; the aspect ratio is 1-2, preferably 1.5-2.

[0023] According to the present invention, preferably, the cathode and anode are each independently selected from one of graphite electrode, metal electrode, metal-coated electrode and diamond electrode.

[0024] According to the present invention, preferably, the cathode includes at least one cathode plate, the anode includes at least one anode plate, and the cathode plates and anode plates are spaced apart, with polyphenylene sulfide particles loaded with carbon fibers filling the spaces between each cathode plate and anode plate. The shapes of the cathode plates and anode plates are not particularly limited and can be shapes commonly used in the art, such as flat plates, meshes, etc.

[0025] According to the present invention, preferably, the cathode plate and the anode plate are each independently selected from at least one of titanium electrode plates, titanium-based ruthenium coated electrode plates, and graphite electrode plates.

[0026] According to the present invention, preferably, the distance between adjacent cathode plates and anode plates during use is 0.5-40 cm (e.g., 0.5 cm, 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 5 cm, 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, and any range of any two of the above points). The dimensions of the cathode plates and anode plates can be reasonably selected according to the amount of wastewater to be treated.

[0027] A second aspect of the present invention provides a three-dimensional electrode reactor, which includes a water distributor 5, an electrode plate 6, and a particle electrode 7. The electrode plate 6 includes at least one cathode plate and at least one anode plate, and the cathode plate and anode plate are spaced apart in the reactor to divide the reactor cavity into multiple parallel channels. The particle electrode is filled in each channel. The water distributor 5 is disposed below the channel for supporting the particle electrode and distributing wastewater. The particle electrode is a polyphenylene sulfide particle loaded with carbon fiber.

[0028] According to a particularly preferred embodiment of the present invention, such as Figure 1 As shown, the shell of the three-dimensional electrode reactor is a sealed shell, with an inlet, an outlet, and an exhaust vent. The inlet and outlet are located at the bottom of the shell, while the exhaust vent is located at the top. Inside the shell are a water distributor 5, an electrode plate 6, and particle electrodes. The water distributor 5 is positioned above the inlet and parallel to the bottom of the shell. The electrode plate 6 is perpendicular to the water distributor 5. Particle electrodes are filled into the channel between the cathode and anode plates, with the filling height of the particle electrodes being the same as or lower than the height of the electrode plate 6. The wastewater undergoes an oxidation-reduction reaction within the area formed by the water distributor 5, electrode plate 6, and particle electrodes 7; therefore, this area is referred to as the reaction chamber.

[0029] According to the present invention, preferably, the carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 10-50% by weight (e.g., 10% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 50% by weight, and any two of the above), preferably 30-40% by weight.

[0030] According to the present invention, preferably, the length of the carbon fiber is 0.1-50 mm (e.g., 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, and any two of the above), preferably 1-4 mm.

[0031] According to the present invention, preferably, the average diameter of the polyphenylene sulfide particles loaded with carbon fibers is 0.1-2 cm (e.g., 0.1 cm, 0.2 cm, 0.3 cm, 0.4 cm, 0.5 cm, 0.6 cm, 0.7 cm, 1 cm, 1.5 cm, 2 cm, and any two of the above), preferably 0.2-0.5 cm; the aspect ratio is 1-2, preferably 1.5-2.

[0032] According to the present invention, preferably, the cathode plate and the anode plate are each independently selected from one of graphite electrodes, metal electrodes, metal-coated electrodes, and diamond electrodes. The shapes of the cathode plate and the anode plate are not particularly limited and can be shapes commonly used in the art, such as flat plates, meshes, etc.

[0033] According to the present invention, preferably, the cathode plate and the anode plate are each independently selected from at least one of titanium electrode plates, titanium-based ruthenium coated electrode plates, and graphite electrode plates.

[0034] According to the present invention, preferably, the distance between adjacent cathode plates and anode plates is 0.5-40 cm (e.g., 0.5 cm, 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 5 cm, 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, and any range of any two of the above points). The dimensions of the cathode plates and anode plates can be reasonably selected according to the amount of wastewater to be treated.

[0035] According to the present invention, preferably, the three-dimensional electrode reactor further includes an overflow chamber separated from the outermost channel by the outermost electrode plate; the overflow chamber may be provided on one side or both sides, and the wastewater flowing through the channel is discharged from the three-dimensional electrode reactor from the overflow chamber.

[0036] According to the present invention, preferably, an upwardly extending overflow weir 8 is provided on the electrode plate between the overflow chamber and the channel.

[0037] A third aspect of the present invention provides a wastewater treatment system, which includes a storage tank 2, the three-dimensional electrode reactor described above, and a gas collection device connected in sequence.

[0038] According to the present invention, the storage tank is used to store wastewater. Preferably, the upper part of the storage tank 2 is provided with an exhaust port 3 for discharging the gas generated during the storage of wastewater, reducing the pressure inside the storage tank 2 and discharging the unabsorbed gas.

[0039] According to the present invention, the gas collection device is used to treat the gas generated by electrolysis in a three-dimensional electrode reactor. Preferably, the gas collection device includes a negative pressure exhaust pipe 11, an absorption tank 12, and a blower exhaust pipe 13 connected in sequence. The negative pressure exhaust pipe 11 can promptly discharge the gas (e.g., chlorine) generated by wastewater electrolysis in the three-dimensional electrode reactor, preventing gas accumulation and potential explosion. The absorption tank contains alkaline solution to absorb some of the gas; the remaining gas can be directly discharged through the blower exhaust pipe, or diluted with air and discharged through the blower exhaust pipe.

[0040] According to the present invention, preferably, the three-dimensional electrode reactor is provided with an exhaust port, which is connected to a negative pressure exhaust pipe 11 so that the gas generated in the three-dimensional electrode reactor enters the absorption tank 12 through the exhaust port and the negative pressure exhaust pipe 11. More preferably, a metal mesh is provided at the connection between the exhaust port and the negative pressure exhaust pipe 11 to prevent the particle electrode from flowing out. The exhaust port and the overflow chamber are located on different sides of the three-dimensional electrode reactor, and the exhaust port is positioned higher than the overflow weir to prevent wastewater from entering the exhaust port.

[0041] According to the present invention, preferably, the system further includes an outlet pipe connected to the overflow chamber, and a return pipe is provided between the outlet pipe and the inlet of the three-dimensional electrode reactor, so that at least part of the electrolyzed wastewater in the outlet pipe is returned to the three-dimensional electrode reactor as circulating water.

[0042] The fourth aspect of the present invention provides a method for electrochemical treatment of wastewater, the method comprising: electrolyzing wastewater using the three-dimensional electrode described in the first aspect, the three-dimensional electrode reactor described in the second aspect, or the system described in the third aspect.

[0043] According to the present invention, preferably, the current density applied by the power source to the electrode plates is 0.1-100 mA / cm². 2 (For example, 0.1 mA / cm) 2 1mA / cm 2 5mA / cm 2 10mA / cm 2 15mA / cm 2 20mA / cm 225mA / cm 2 30mA / cm 2 35mA / cm 2 40mA / cm 2 50mA / cm 2 70mA / cm 2 90mA / cm 2 100mA / cm 2 (and the range formed by any two of the above points).

[0044] According to the present invention, preferably, the residence time of wastewater in the three-dimensional electrode reactor is 5-180 min. In the present invention, the residence time of wastewater in the three-dimensional electrode reactor refers to the time taken for the wastewater to travel from the inlet to the outlet of the three-dimensional electrode reactor.

[0045] According to the present invention, preferably, 5-50% of the electrolyzed wastewater is returned to the three-dimensional electrode reactor as circulating water. Returning 5-50% of the electrolyzed wastewater to the three-dimensional electrode reactor as circulating water using the above method increases turbulence, further improving the removal rate of organic matter and / or nitrogen-containing compounds from the wastewater.

[0046] According to the present invention, preferably, the TN (nitrogen-containing compounds) in the wastewater is 5-8000 mg / L.

[0047] According to the present invention, preferably, the COD in the wastewater Cr (Organic matter) = 50-1000 mg / L.

[0048] As is known to those skilled in the art, when the salt content in wastewater meets the conductivity requirements, the wastewater can be directly electrolyzed; when the conductivity of the wastewater is too low to allow electrolysis to proceed normally, salt can be added to the wastewater to improve its conductivity. Preferably, the salt content in the wastewater after salt addition is 500-100000 mg / L.

[0049] In a preferred embodiment, the wastewater electrochemical treatment method of the present invention can simultaneously remove organic matter and nitrogen-containing compounds from wastewater. The types of organic matter may include phenols, anilines, nitrobenzenes, etc., and the types of nitrogen-containing compounds may include organic nitrogen and ammonia nitrogen. The wastewater may originate from wastewater from industries such as pesticides, dyes, leather, and pharmaceuticals, as well as treated effluent.

[0050] According to the present invention, preferably, the negative pressure setting range of the negative pressure exhaust pipe 11 is -100Pa to -100KPa.

[0051] The following combination Figure 1The working principle of the wastewater treatment system of the present invention is described in detail as follows: Wastewater enters the storage tank 2 through the inlet pipe 1, and is then pumped into the three-dimensional electrode reactor by the pump 4. After being evenly distributed by the water distributor 5, the wastewater enters the channel formed by the water distributor 5, the cathode plate, and the anode plate, where it comes into contact with the cathode plate, the anode plate, and the particle electrode to undergo an oxidation-reduction reaction. The electrolyzed wastewater flows through the overflow weir 8 and enters the overflow chamber, and then returns part of the electrolyzed wastewater to the three-dimensional electrode reactor through the outlet pipe connected to the overflow chamber. The gases (such as chlorine and hydrogen) generated during the oxidation-reduction reaction in the three-dimensional electrode reactor enter the absorption tank 12 through the exhaust port and the negative pressure exhaust pipe 11 at the top of the three-dimensional electrode reactor. After being absorbed by the alkaline solution, the gases are discharged through the blower exhaust pipe.

[0052] The present invention will be described in detail below through embodiments. In the following embodiments,

[0053] The titanium electrode plate is manufactured by Shaanxi Tels Industrial Technology Co., Ltd.

[0054] The manufacturer of the titanium-based ruthenium-coated electrode is Shaanxi Tels Industrial Technology Co., Ltd., and the content of ruthenium-iridium mixed oxide in the electrode is ≥8g / m³. 2 ;

[0055] The manufacturer of the mesh titanium electrode plate is Shaanxi Tels Industrial Technology Co., Ltd.

[0056] Both the graphite electrode plates and the polyphenylene sulfide particles loaded with carbon fibers are commercially available products.

[0057] The test method for COD is the potassium dichromate method, HJ 828-2017.

[0058] The test method for TN is HJ 636-2012 Alkaline potassium persulfate digestion ultraviolet spectrophotometry.

[0059] Example 1

[0060] The wastewater treatment system includes a storage tank 2, a three-dimensional electrode reactor, and a gas collection device connected in sequence. The three-dimensional electrode reactor includes a water distributor 5, electrode plates 6, and particle electrodes 7 (polyphenylene sulfide particles loaded with carbon fibers). Electrode plates 6 include four cathode plates and three anode plates, spaced apart to divide the reactor chamber into multiple parallel channels. The particle electrodes fill each channel. The water distributor 5 is located below the channels to support the particle electrodes and distribute wastewater. The gas collection device includes a negative pressure exhaust pipe 11, an absorption tank 12, and a blower exhaust pipe 13 connected in sequence.

[0061] The cathode plate is made of titanium, and the anode plate is made of titanium-based ruthenium-coated electrode. The cathode and anode plates are spaced apart, with a distance of 2 cm between adjacent plates. The dimensions of both the cathode and anode plates are 11 cm × 8 cm × 0.1 cm. The anode and cathode plates are connected to the positive and negative terminals of the power supply, respectively. The current density applied to the electrode plates by the power supply is 30 mA / cm². 2 The carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 40% by weight, the number average fiber length of the carbon fiber is 3 mm, the average diameter of the carbon fiber-loaded polyphenylene sulfide particles is 0.2 cm, and the aspect ratio is 1.5.

[0062] The dye factory generates high-salinity wastewater (salt content 5000 mg / L) with a COD of 300 mg / L. This wastewater enters storage tank 2 through inlet pipe 1, and its pH is measured to be 7. The wastewater then enters the three-dimensional electrode reactor (3D electrode reactor) via pump 4, and after being evenly distributed by a distributor, it enters the tank formed by the distributor 5, cathode plate, and anode plate. Pollutants in the wastewater undergo oxidation-reduction reactions within the 3D electrode reactor. The residence time of the wastewater in the 3D electrode reactor is 60 minutes. The treated wastewater flows through overflow weir 8 into overflow chamber, and 20% of the water in the overflow chamber's outlet pipe is returned to the 3D electrode reactor via a return pipe. The treated wastewater has a COD of 38 mg / L, which is less than the standard requirement of 50 mg / L. Under the condition that the treated wastewater meets the standard, the particle electrode can operate stably for a long period without the need for separate regeneration.

[0063] When a redox reaction occurs in the three-dimensional electrode reactor, the gases produced (such as chlorine and hydrogen) enter the gas collection device through the exhaust port at the top of the reactor. The negative pressure exhaust pipe 11 is set to -500 Pa. The absorption tank 12 contains alkaline solution, and the generated gases are absorbed by the alkaline solution and then discharged through the blower exhaust pipe.

[0064] Example 2

[0065] The wastewater treatment system includes a storage tank 2, a three-dimensional electrode reactor, and a gas collection device connected in sequence. The three-dimensional electrode reactor includes a water distributor 5, electrode plates 6, and particle electrodes 7 (polyphenylene sulfide particles loaded with carbon fibers). The electrode plates 6 include five cathode plates and four anode plates, spaced apart to divide the reactor chamber into multiple parallel channels. The particle electrodes fill each channel. The water distributor 5 is located below the channels to support the particle electrodes and distribute wastewater. The gas collection device includes a negative pressure exhaust pipe 11, an absorption tank 12, and a blower exhaust pipe 13 connected in sequence.

[0066] The cathode plate is made of titanium, and the anode plate is made of titanium-based ruthenium-coated electrode. The distance between two adjacent electrode plates is 2 cm. The dimensions of both the cathode and anode plates are 11 cm × 8 cm × 0.1 cm. The anode and cathode plates are connected to the positive and negative terminals of the power supply, respectively. The current density applied to the electrode plates by the power supply is 20 mA / cm². 2 The carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 30% by weight, the number average fiber length of the carbon fiber is 4 mm, the average diameter of the carbon fiber-loaded polyphenylene sulfide particles is 0.2 cm, and the aspect ratio is 2.

[0067] The electroplating plant's nitrogen-containing wastewater has a TN of 507 mg / L, a COD of 111 mg / L, and a salt content of 1000 mg / L. This wastewater enters the storage tank 2 through inlet pipe 1, and its pH is measured to be 8. The wastewater then enters the three-dimensional electrode reactor (3D electrode reactor) via pump 4, and after being evenly distributed by a distributor, it enters the tank formed by the distributor 5, cathode plate, and anode plate. The pollutants in the wastewater undergo oxidation-reduction reactions within the 3D electrode reactor. The residence time of the wastewater in the 3D electrode reactor is 40 minutes. The treated wastewater flows through overflow weir 8 into the overflow chamber, and then 20% of the water in the overflow chamber's outlet pipe is returned to the 3D electrode reactor via a return pipe. The treated wastewater has a TN of 12 mg / L and a COD of 26 mg / L, which are less than the standard requirements of 15 mg / L and 50 mg / L, respectively. Under the condition that the treated wastewater meets the standards, the particle electrode can operate stably for a long period without the need for separate regeneration.

[0068] When a redox reaction occurs in the three-dimensional electrode reactor, the gases produced (such as chlorine and hydrogen) enter the gas collection device through the exhaust port at the top of the reactor. The negative pressure exhaust pipe 11 is set to -500 Pa. The absorption tank 12 contains alkaline solution, and the generated gases are absorbed by the alkaline solution and then discharged through the blower exhaust pipe.

[0069] Example 3

[0070] The wastewater treatment system includes a storage tank 2, a three-dimensional electrode reactor, and a gas collection device connected in sequence. The three-dimensional electrode reactor includes a water distributor 5, electrode plates 6, and particle electrodes 7 (polyphenylene sulfide particles loaded with carbon fibers). The electrode plates 6 include four cathode plates and three anode plates, spaced apart to divide the reactor chamber into multiple parallel channels. The particle electrodes fill each channel. The water distributor 5 is located below the channels to support the particle electrodes and distribute wastewater. The gas collection device includes a negative pressure exhaust pipe 11, an absorption tank 12, and a blower exhaust pipe 13 connected in sequence.

[0071] The cathode plate is a mesh titanium plate, and the anode plate is a titanium-based ruthenium-coated plate. The cathode and anode plates are spaced apart, with a distance of 2 cm between adjacent plates. Both the cathode and anode plates measure 11 cm × 8 cm × 0.1 cm. The anode and cathode plates are connected to the positive and negative terminals of the power supply, respectively. The current density applied to the plates by the power supply is 40 mA / cm². 2 The carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 40% by weight, the carbon fiber length is 3 mm with a number average fiber length, the average diameter of the carbon fiber-loaded polyphenylene sulfide particles is 0.2 cm, and the aspect ratio is 1.5.

[0072] The nitrogen-containing wastewater from the fertilizer plant has a TN of 1665 mg / L, a COD of 84 mg / L, and a salt content of 500 mg / L. The wastewater enters the storage tank 2 through inlet pipe 1, and the pH is measured to be 8. The wastewater then enters the three-dimensional electrode reactor (3D electrode reactor) via pump 4, and after being evenly distributed by a distributor, it enters the tank formed by the distributor 5, cathode plate, and anode plate. The pollutants in the wastewater undergo oxidation-reduction reactions within the 3D electrode reactor. The residence time of the wastewater in the 3D electrode reactor is 40 minutes. The treated wastewater enters the overflow chamber through overflow weir 8, and then 50% of the water in the overflow chamber's outlet pipe is returned to the 3D electrode reactor via a return pipe. The treated wastewater has a TN of 11 mg / L and a COD of 21 mg / L, which are less than the standard requirements of 15 mg / L and 50 mg / L, respectively. Under the condition that the treated wastewater meets the standards, the particle electrode can operate stably for a long period without the need for separate regeneration.

[0073] When a redox reaction occurs in the three-dimensional electrode reactor, the gases produced (such as chlorine and hydrogen) enter the gas collection device through the exhaust port at the top of the reactor. The negative pressure exhaust pipe 11 is set to -500 Pa. The absorption tank 12 contains alkaline solution, and the generated gases are absorbed by the alkaline solution and then discharged through the blower exhaust pipe.

[0074] Example 4

[0075] The wastewater treatment system includes a storage tank 2, a three-dimensional electrode reactor, and a gas collection device connected in sequence. The three-dimensional electrode reactor includes a water distributor 5, electrode plates 6, and particle electrodes 7 (polyphenylene sulfide particles loaded with carbon fibers). The electrode plates 6 include four cathode plates and three anode plates, spaced apart to divide the reactor chamber into multiple parallel channels. The particle electrodes fill each channel. The water distributor 5 is located below the channels to support the particle electrodes and distribute wastewater. The gas collection device includes a negative pressure exhaust pipe 11, an absorption tank 12, and a blower exhaust pipe 13 connected in sequence.

[0076] Both the cathode and anode plates are made of graphite and are spaced apart. The dimensions of both plates are 11cm × 8cm × 0.1cm, with a distance of 2cm between adjacent plates. The anode and cathode plates are connected to the positive and negative terminals of the power supply, respectively. The current density applied to the plates is 10mA / cm². 2 The carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 40% by weight, the number average fiber length of the carbon fiber is 3 mm, the average diameter of the carbon fiber-loaded polyphenylene sulfide particles is 0.3 cm, and the aspect ratio is 2.

[0077] A synthetic fiber factory produces membrane concentrate (high-salinity wastewater, salt content 100,000 mg / L) with a COD of 109 mg / L. This high-salinity wastewater enters a storage tank 2 via inlet pipe 1, and its pH is measured to be 7. The wastewater then enters the three-dimensional electrode reactor (3DE reactor) via pump 4, and after being evenly distributed by a distributor, it enters the tank formed by the distributor 5, cathode plate, and anode plate. Pollutants in the wastewater undergo oxidation-reduction reactions within the 3DE reactor. The residence time of the wastewater in the 3DE reactor is 60 minutes. The treated wastewater flows through an overflow weir 8 into an overflow chamber, and 40% of the water from the overflow chamber's outlet pipe is returned to the 3DE reactor via a return pipe. The treated wastewater has a COD of 38 mg / L, which is less than the standard requirement of 50 mg / L. As long as the treated wastewater meets the standard, the particle electrode can operate stably for a long period without the need for separate regeneration.

[0078] When a redox reaction occurs in the three-dimensional electrode reactor, the gases produced (such as chlorine and hydrogen) enter the gas collection device through the exhaust port at the top of the reactor. The negative pressure exhaust pipe 11 is set to -500 Pa. The absorption tank 12 contains alkaline solution, and the generated gases are absorbed by the alkaline solution and then discharged through the blower exhaust pipe.

[0079] Example 5

[0080] The procedure was carried out according to Example 3, except that the carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles was 15% by weight. The treated wastewater had TN = 360 mg / L and COD = 46 mg / L.

[0081] Example 6

[0082] The procedure was carried out according to Example 3, except that the particle size of the polyphenylene sulfide particles loaded with carbon fibers was 0.5 cm and the aspect ratio was 3. The treated wastewater had a TN of 241 mg / L and a COD of 40 mg / L.

[0083] Comparative Example 1

[0084] The procedure was carried out according to Example 3, except that the carbon fiber-loaded polyphenylene sulfide particles were replaced with conductive polyurethane material. The treated wastewater had a TN concentration of 1050 mg / L and a COD concentration of 49 mg / L.

[0085] When conductive polyurethane material is used as the filler electrode, it not only fails to make the treated wastewater meet the standards, but also causes the conductive polyurethane material to burn after 0.5 hours of wastewater treatment.

[0086] Comparative Example 2

[0087] The method was carried out according to Example 3, except that activated carbon was replaced with polyphenylene sulfide particles loaded with carbon fibers. The treated wastewater had TN = 84 mg / L and COD = 41 mg / L.

[0088] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A three-dimensional electrode, characterized in that, The three-dimensional electrode includes a cathode, an anode, and a particle electrode that fills the space between the cathode and the anode during use. The particle electrode is a polyphenylene sulfide particle loaded with carbon fibers. The average diameter of the polyphenylene sulfide particle loaded with carbon fibers is 0.1-0.4 cm, the aspect ratio is 1-2, and the carbon fiber content in the polyphenylene sulfide particle loaded with carbon fibers is 30-50% by weight.

2. The three-dimensional electrode according to claim 1, wherein, The carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 30-40% by weight.

3. The three-dimensional electrode according to claim 1, wherein, The number-average fiber length of the carbon fiber is 0.1-50 mm.

4. The three-dimensional electrode according to claim 1, wherein, The number-average fiber length of the carbon fiber is 1-4 mm.

5. The three-dimensional electrode according to claim 1, wherein, The aspect ratio of the polyphenylene sulfide particles loaded with carbon fibers is 1.5-2.

6. The three-dimensional electrode according to claim 1, wherein, The cathode and anode are each independently selected from one of the following: graphite electrode, metal electrode, metal-coated electrode, and diamond electrode.

7. The three-dimensional electrode according to claim 1, wherein, The cathode includes at least one cathode plate, the anode includes at least one anode plate, and the cathode plates and anode plates are spaced apart, with each cathode plate and anode plate filled with polyphenylene sulfide particles loaded with carbon fibers.

8. The three-dimensional electrode according to claim 7, wherein, When in use, the distance between adjacent cathode plates and anode plates should be 0.5-40cm.

9. A three-dimensional electrode reactor, characterized in that, The reactor includes a water distributor (5), an electrode plate (6), and a particle electrode (7). The electrode plate (6) includes at least one cathode plate and at least one anode plate, and the cathode plate and anode plate are spaced apart in the reactor to divide the reactor cavity into multiple parallel channels. The particle electrode is filled in each channel. The water distributor (5) is located below the channel to support the particle electrode and distribute wastewater. The particle electrode is a polyphenylene sulfide particle loaded with carbon fiber. The average diameter of the carbon fiber-loaded polyphenylene sulfide particles is 0.1-0.4 cm; the aspect ratio is 1-2; and the carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 30-50% by weight.

10. The three-dimensional electrode reactor according to claim 9, wherein, The carbon fiber content in the carbon fiber-loaded polyphenylene sulfide particles is 30-40% by weight.

11. The three-dimensional electrode reactor according to claim 9, wherein, The number-average fiber length of the carbon fiber is 0.1-50 mm.

12. The three-dimensional electrode reactor according to claim 9, wherein, The number-average fiber length of the carbon fiber is 1-4 mm.

13. The three-dimensional electrode reactor according to claim 9, wherein, The aspect ratio of the polyphenylene sulfide particles loaded with carbon fibers is 1.5-2.

14. The three-dimensional electrode reactor according to claim 9, wherein, The cathode plate and anode plate are each independently selected from one of the following: graphite electrode, metal electrode, metal-coated electrode, and diamond electrode. And / or, the distance between adjacent cathode plates and anode plates is 0.5-40cm.

15. The three-dimensional electrode reactor according to any one of claims 9-14, wherein, The three-dimensional electrode reactor also includes an overflow chamber separated from the outermost channel by the outermost electrode plate.

16. The three-dimensional electrode reactor according to claim 15, wherein, An upward-extending overflow weir (8) is provided on the electrode plate between the overflow chamber and the channel.

17. A wastewater treatment system, characterized in that, The system includes a liquid storage tank (2), a three-dimensional electrode reactor as described in any one of claims 9-16, and a gas collection device connected in sequence.

18. The system according to claim 17, wherein, The gas collection device includes a negative pressure exhaust pipe (11), an absorption tank (12), and a blower exhaust pipe (13) connected in sequence.

19. The system according to claim 17 or 18, wherein, The system also includes an outlet pipe (9) connected to the overflow chamber, and a return pipe (10) is provided between the outlet pipe (9) and the inlet of the three-dimensional electrode reactor, so that at least part of the electrolyzed wastewater in the outlet pipe (9) is returned to the three-dimensional electrode reactor as circulating water.

20. A method for electrochemical treatment of wastewater, characterized in that, The method includes: using a three-dimensional electrode as described in any one of claims 1-8, a three-dimensional electrode reactor as described in any one of claims 9-16, or a system for electrolyzing wastewater as described in any one of claims 17-19.

21. The method according to claim 20, wherein, The current density applied by the power source to the electrode plates is 0.1-100 mA / cm². 2 .

22. The method according to claim 20, wherein, The residence time of wastewater in the three-dimensional electrode reactor is 5-180 min; And / or, 5-50% of the wastewater after electrolysis is returned to the three-dimensional electrode reactor as circulating water.

23. The method according to any one of claims 20-22, wherein, TN in wastewater = 5-8000 mg / L; And / or, COD in wastewater Cr =50-1000mg / L.

24. The method according to any one of claims 20-22, wherein, The negative pressure setting range of the negative pressure exhaust pipe (11) is -100Pa to -100KPa.

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