A dynamic three-dimensional electrode flocculation coupled wastewater treatment device and method

Abstract

This invention discloses a dynamic three-dimensional electrode flocculation coupling wastewater treatment device and method, including an electrolytic cell, a reaction tank, a rotating shaft, a stirrer, a peristaltic pump, an anode, and a cathode. The anode and cathode are respectively installed on both sides of the rotating shaft and inserted into the electrolytic cell. Sludge fills the space between the cathode and the anode and is in contact with both the cathode and the anode, realizing a dynamic three-dimensional electrode. The anode and cathode are connected in parallel. A chelating agent is added to the reaction tank for stirring. This treatment device not only increases the degradation efficiency of various heavy metal ions, but also reduces the reaction time, significantly reduces the reaction cost, and can effectively realize the waste utilization of industrial sludge. In addition, the method provided in this application includes: injecting industrial wastewater into the electrolytic cell, applying electricity for treatment, and then entering the reaction tank for deep treatment. This method is simple and can effectively promote the degradation of various heavy metal ions.

Description

Technical Field

[0001] This invention belongs to the field of heavy metal wastewater treatment technology, and particularly relates to a dynamic three-dimensional electrode flocculation coupling wastewater treatment device and method. Background Technology

[0002] In recent years, my country's continuous industrial development has generated a large amount of wastewater, waste residue, and exhaust gas, causing serious environmental impacts, including ecosystem degradation and human health problems. The most prominent hazard is industrial wastewater, especially wastewater containing heavy metal ions. Large quantities of untreated industrial wastewater, or wastewater that does not meet national emission standards, are discharged into the natural environment from production and daily life, seeping into groundwater and soil. This poses a serious threat to the entire ecological environment, human health, and the sustainable development of society and the economy.

[0003] Three-dimensional electrodes are based on the traditional two-dimensional electrolysis environment. Particulate or fragmented materials (such as ceramics, activated carbon, and metal slag) are added as working electrodes to the electrolytic cell. Due to their surface charge, electrochemical reactions occur in the solution, forming a three-dimensional environment. As a novel reactor, the three-dimensional electrochemical reactor solves the problems of high energy consumption and low treatment efficiency of traditional two-dimensional electrodes, achieving low cost, simple structure, and ease of operation. The mechanism of three-dimensional electrodes is similar to that of electrocatalytic oxidation. The three-dimensional electrode method can be divided into direct oxidation, indirect oxidation, and electroadsorption catalytic oxidation on the packing surface. However, it is subject to certain limitations in practical applications. Besides the energy consumption caused by the applied voltage, anolyte dissolution causes electrode plate wear. When treating heavy metal wastewater, the electrode plates are easily passivated, and an oxide film forms on the surface of the anode plate, reducing treatment efficiency and increasing energy consumption. Therefore, the current development trend is to deepen the research on three-dimensional electrodes and solve the problem of electrode plate passivation.

[0004] Flocculation is a common and effective technique for removing heavy metal ions from polluted water sources. When flocculants are added to water, colloidal particles, including heavy metal ions, aggregate into larger flocs. Flocculation has been widely applied in various fields, primarily including the treatment of heavy metal wastewater (chromium, copper, zinc, nickel, cadmium, lead, manganese, mercury, and cobalt), dye wastewater (acid dyes, reactive dyes, and disperse dyes), and other wastewater. In the field of heavy metal wastewater treatment, the complex composition of heavy metal ions limits the degradation efficiency of flocculation. Therefore, a multi-technology approach with low energy consumption to achieve the dual recovery of wastewater and heavy metals offers a new solution for the radical treatment of heavy metal-containing wastewater and warrants further research. In view of this, the present invention is proposed. Summary of the Invention

[0005] (1) Technical problem to be solved: In view of the problems existing in traditional technology, the present invention provides a dynamic three-dimensional electrode flocculation coupling wastewater treatment device and method.

[0006] (2) The technical solution adopted in this invention is as follows: A dynamic three-dimensional electrode flocculation coupling wastewater treatment device includes an electrolytic cell, a reaction cell, a rotating shaft, a drive motor, an anode and a cathode. The rotating shaft is connected to the output shaft of the drive motor. The rotating shaft is located inside the electrolytic cell. A support is connected to the lower part of the rotating shaft. The anode and cathode are respectively fixed at both ends of the support. Sludge is set inside the electrolytic cell. The anode and cathode are inserted into the sludge. The electrolytic cell is connected to the peristaltic pump and the reaction cell in sequence through a pipe. A stirring device is set inside the reaction cell.

[0007] This application designs a rotary electrode reactor, which utilizes industrial waste sludge to form parallel three-dimensional electrodes for the deep treatment of heavy metal wastewater, thereby more efficiently reducing various heavy metal ions in the water. Because the rotary electrode reactor in this application effectively prevents passivation reactions of the electrode plates, it extends the service life of the electrode plates, significantly reducing the treatment cost of heavy metal wastewater. This makes the dynamic three-dimensional electrode-flocculation coupling device more economical and widely applicable.

[0008] The sludge residue used in this application can increase the probability of collision with sulfides, enhance the effect of net capture and sweeping, and at the same time, the excess agents remaining in the sludge can be reused, which is beneficial to resist the shock load of water quality and quantity in actual treatment. In addition, because the sludge residue contains a variety of metal components, it also increases the current density, promotes better conductivity of the electrodes, and is conducive to electrochemical coupling.

[0009] The anode and cathode are arranged opposite each other, and both have dimensions of 2.0cm × 0.6cm × 32cm. The area of ​​the anode and cathode inserted below the liquid surface in the electrolytic cell is 75-85% of the total surface area of ​​the anode and cathode; that is, the effective area of ​​the anode and cathode accounts for approximately 75-85% of their total area, which ensures the smooth progress of the reaction and effective electrolysis. Preferably, the distance between the anode and cathode is 40-45cm. This distance ensures effective filling of the sludge and a reasonable electric field strength.

[0010] In this application, there are various options for the anode. In typical but non-limiting examples, the anode can be a carbon-based electrode, a metal electrode, a metal composite supported electrode, or a ceramic electrode. Preferably, the anode is a metal electrode; more preferably, the metal electrode is a titanium electrode. Titanium electrodes are common reaction electrodes, which are lost during the reaction process. However, in this application, the electrode loss is effectively reduced by using a rotating electrode reactor. Therefore, this invention meets the standards of being economical, efficient, and universally applicable.

[0011] A method for treating wastewater based on a dynamic three-dimensional electrode flocculation coupling wastewater treatment device includes the following steps: S1: Inject the heavy metal wastewater into the electrolytic cell; S2: Add electrolytes to heavy metal wastewater and adjust the pH to between 8 and 9; S3: The two electrode plates should be soaked in an acid solution before use. S4; The sludge residue is placed in an ethanol solution, washed with ultrasonic water, dried, and then filled between the two electrode plates. S5: Connect the cathode and anode to the power supply. Apply a DC power supply voltage of 4-10V for 90-120 minutes. Before energizing, adjust the pH of the solution in the electrolytic cell to 9. S6: After the reaction in the electrolytic cell has lasted for 100 minutes, the wastewater is injected into the reaction cell through a peristaltic pump; S7: Add chelating agent to the wastewater in the reaction tank, adjust the pH to between 7 and 10, and stir for 20 minutes.

[0012] In this application, the electrolytic cell contains an electrolyte, which is a sulfide, including one or a mixture of two of K₂S and Na₂S. Preferably, the concentration of the sulfide in the solution to be electrolyzed in the electrolytic cell is 80-120 mg / L. In this application, by selecting a sulfide as the electrolyte, the ions in the sulfide solid electrolyte undergo a redox reaction with water molecules, being oxidized to sulfate. The sulfate can then generate sulfate radicals and strongly oxidizing hydroxyl radicals under the combined excitation of the cathode and anode, thereby degrading various heavy metal ions in the wastewater. Before inserting the cathode into the electrolytic cell, the cathode is further immersed in an acid solution for cleaning. Preferably, the acid solution includes one or a mixture of two of hydrochloric acid and sulfuric acid. Preferably, the volume concentration of the acid solution is 5-15%. Preferably, the immersion time is 10-15 min. Since a small amount of electrolyte may adhere to the surface of the cathode during the reaction, cleaning the cathode with an acid solution in this application is beneficial for the next use of the cathode. In this application, in order to improve the utilization rate of sludge, the sludge is pretreated to remove impurities or oxides from its surface, thereby enabling the sludge to form a dynamic three-dimensional oxidation-reduction electrochemical reaction device with the cathode, anode, and electrolyte, which is beneficial for the deep treatment of heavy metal wastewater.

[0013] A further technical solution is that the acid solution includes one or a mixture of two of hydrochloric acid and sulfuric acid, and the volume concentration of the acid solution is 5-15%.

[0014] A further technical solution is to soak the electrode plates in S3 for 10-15 minutes and keep the distance between the plates at 40-45 cm.

[0015] A further technical solution is that the anode is a carbon-based electrode, a metal electrode, a metal composite load electrode, or a ceramic electrode, and the cathode is a ruthenium-iridium electrode. The area of ​​the anode and cathode inserted below the liquid surface in the electrolytic cell is 75-85% of the total surface area of ​​the anode and the cathode.

[0016] A further technical solution is that the concentration of the chelating agent is 200-300 mg / L.

[0017] A further technical solution is that the electrolyte is a sulfide, preferably, the persulfate includes one or a mixture of two of K2S and Na2S, and the concentration of the sulfide in the solution to be electrolyzed in the electrolytic cell is 80-120 mg / L.

[0018] A further technical solution is that the dielectric is K2S, and 0.1g of K2S is added per liter of wastewater.

[0019] A further technical solution is that, in step S4, the power of the ultrasonic wave is 80-100 watts; the ultrasonic water washing time is 10-15 minutes; and the drying is carried out at a temperature of 62-70℃ for 30-45 minutes.

[0020] A further technical solution is to add 35-40g of the sludge residue to each liter of the industrial wastewater.

[0021] (3) Due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This application relates to a dynamic three-dimensional electrode in which the anode and cathode can be rotated by a rotating shaft under the drive of a motor. Compared with traditional fixed electrodes, in the dynamic rotating electrode, the polarization behavior of the anode electrode plate exhibits the common characteristics of solubility, and passivation under static conditions no longer occurs. At a certain rotation speed, it accelerates the reaction of Cl... - The spread of.

[0022] 2. A three-dimensional electroreaction environment is formed by the anode, cathode, and sludge filling the space between the anode and cathode. The sludge can increase the probability of collision with sulfides, enhance the effect of netting and sweeping, and the excess reagents remaining in the sludge can be reused, which is beneficial to resist the shock load of water quality and quantity in actual treatment. In addition, the sludge has a variety of metal components, which also increases the current density, promotes better conductivity of the electrodes, and facilitates electrochemical coupling.

[0023] 3. In this application, the added chelating agent is rich in groups such as amine, hydroxyl and thiol, which can provide a large number of coordination ions to strongly adsorb suspended solids or colloidal particles in wastewater, and form stable network cross-linked chelates with heavy metal ions. Under the chelation effect, small molecules in the solution form large molecules through adsorption, and small particles form large particles through bridging, generating precipitates with relatively large molecular weight, thereby achieving the effect of deep removal of heavy metals.

[0024] 4. The dynamic three-dimensional electrode flocculation coupling device provided in this application not only increases the degradation efficiency of various heavy metal ions in wastewater, but also reduces reaction time, lowers electrode plate wear, significantly reduces reaction costs, and effectively realizes the utilization of industrial sludge. The method for treating heavy metal wastewater using the dynamic three-dimensional electrode-flocculation coupling device provided in this application involves injecting heavy metal wastewater into the aforementioned device followed by electro-flocculation treatment. This method is simple, easy to operate, and effectively promotes the degradation of various heavy metal ions in wastewater. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 yes Figure 1 Schematic diagram of the structure at point A; Figure 3 yes Figure 1 Schematic diagram of the structure at point B; Figure 4 This is a schematic diagram of the structure of the anode wire and cathode wire described in this invention within the support; Figure 5 This is a diagram illustrating the degradation effect of heavy metal ions in wastewater in an embodiment of the present invention; Figure 6 This is a graph showing the degradation effect of different sludge dosages on heavy metal ions in wastewater, provided in the embodiments of the present invention. Figure 7 This is a graph showing the degradation effect of different dosages of the chelating agent provided in this embodiment of the invention on heavy metal ions in wastewater; Figure 8 This is a diagram showing the degradation effect of different applied voltages on heavy metal ions in wastewater, provided in an embodiment of the present invention. Figure 9 This is a schematic diagram of the device of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] like Figures 1-9 As shown.

[0028] Example 1: A dynamic three-dimensional electrode flocculation coupled wastewater treatment device includes an electrolytic cell 1, a reaction tank 2, a rotating shaft 3, a drive motor 4, an anode 5, and a cathode 6. The rotating shaft 3 is connected to the output shaft of the drive motor 4 and is located inside the electrolytic cell 1. A support 7 is connected to the lower part of the rotating shaft 3. The anode 5 and the cathode 6 are respectively fixed at both ends of the support 7. Sludge is placed inside the electrolytic cell 1, and the anode 5 and the cathode 6 are inserted into the sludge. The electrolytic cell 1 is connected to the peristaltic pump 8 and the reaction tank 2 in sequence through pipes. A stirring device 10 is installed inside the reaction tank 2.

[0029] The support 7 has a hollow structure. The anode 5 and cathode 6 are connected to the support 7 by an insulated connection structure. The insulated connection structure includes connection holes on the support 7. The anode 5 and cathode 6 are inserted into the corresponding connection holes. A limiting cap 11 is provided at the upper end of both the anode 5 and cathode 6. Taking the anode 5 as an example, an insulating plate 12 and a pad 13 (both insulating plates 12 and 13 are made of insulating materials; the insulating plate 12 is plastic, and the pad 13 is rubber) are provided at the top of the limiting cap 11 of the anode 5. A second pad 14 is provided between the bottom of the limiting cap 11 of the anode 5 and the support 7. The anode 5 passes through the second pad 14. The insulating plate 12 is fixed to the support 7 by bolts 15. An insulating sleeve 16 (made of plastic or rubber) is provided on the upper part of the anode 5 to insulate the anode 5 from the support 7 and the cathode 6 from the support 7. A rotating shaft 3 is connected to the middle of the support 7. The rotating shaft 3 is fixed to the output shaft of the drive motor 4 by a coupling. A second insulating sleeve 17 (made of plastic or rubber) is provided on the rotating shaft 3. An anode conductive ring 19 and a cathode conductive ring 20 are fitted onto the outer sleeve 17. Both the anode conductive ring 19 and the cathode conductive ring 20 are fixed to the rotating shaft 3 by set screws. An anode carbon brush 21 and a cathode carbon brush 22 are installed on the support 18 at the top of the electrolytic cell 1. The anode carbon brush 21 is slidably connected to the anode conductive ring 19, and the cathode carbon brush 22 is slidably connected to the cathode conductive ring 20. The anode carbon brush 21 and the cathode carbon brush 22 are connected to a power supply 23. An anode wire 24 and a cathode wire 25 are installed inside the rotating shaft 3. One end of the anode wire 24... The anode conductor 24 is connected to the anode conductive ring 19 (a hole is provided on the side wall of the rotating shaft 3), and the other end of the anode conductor 24 extends into the interior of the bracket 7 (a through hole is provided in the middle of the bracket 7) and is connected to the anode 5. One end of the cathode conductor 25 is connected to the cathode conductive ring 20 (a hole is provided on the side wall of the rotating shaft 3), and the other end of the cathode conductor 25 extends into the interior of the bracket 7 (a through hole is provided in the middle of the bracket 7) and is connected to the cathode 6. This can satisfy the requirement that when the drive motor 4 drives the rotating shaft 3, the bracket 7, the cathode 6, and the anode 5 to rotate, it can supply power to the anode 5 and the cathode 6.

[0030] This application provides a method for treating heavy metal wastewater using dynamic three-dimensional electrode-flocculation coupling, which includes the following steps: (1) Inject 15L of heavy metal wastewater into a dynamic three-dimensional electrochemical reactor.

[0031] (2) Add 100 mg / L of K2S to the heavy metal wastewater and adjust the pH to 8.

[0032] (3) The aluminum anode plate and the ruthenium-iridium cathode plate were selected as the two electrode plates. The dimensions of both plates were 2.0cm×0.6cm×32cm (length×width×height). Before use, they were soaked in 10% dilute hydrochloric acid for 10 minutes.

[0033] (4) Install the aluminum electrode plate and the ruthenium-iridium electrode on both sides of the rotating shaft, keeping the distance between the electrode plates at 40 cm. Place the sludge residue in an ethanol solution, wash it with ultrasonic water at 100 watts, and then dry it at 65°C for 40 min. Subsequently, fill the space between the two electrode plates with 35 g of sludge residue. The effective area of ​​the two electrode plates is 75% of the total area.

[0034] (5) Connect the rotating shaft to the power supply (Note: the anode and cathode of the power supply are connected to the two sides of the rotating shaft respectively). The DC power supply applies a voltage of 6V and the power supply time is 100min.

[0035] (6) After the reaction in the electrolytic cell is completed for 100 minutes, the wastewater is injected into the reaction cell through a peristaltic pump for further treatment.

[0036] (7) Add 200 mg / L of chelating agent to the wastewater in the reaction tank, adjust the pH to 9, turn on the power, and stir continuously for 20 minutes. The chelating agent is a water treatment agent for the deep treatment of thallium-containing wastewater from non-ferrous smelting, as proposed in invention patent application publication number CN121554069A. It is rich in amino, hydroxyl, and mercapto groups, which can provide a large number of coordination ions to strongly adsorb suspended solids or colloidal particles in the wastewater.

[0037] (8) Immediately after the event, the levels of various heavy metals in the wastewater were measured. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg were 97.46%, 98.97%, 95.26%, 75.94%, 77.27%, and 89.79%, respectively.

[0038] (9) The anode material used in this experiment is an aluminum plate, and the cathode is a ruthenium-iridium electrode plate. The cathode is not considered a consumable, and the loss of the aluminum anode under dynamic conditions is negligible. The dosage of K2S used to treat one wastewater cycle is 100 mg / L, i.e., 0.1 g of K2S is added per liter of wastewater. The market price for 500 g of K2S is 60 yuan. The experimental treatment voltage is 6V. According to the energy consumption formula, this system consumes 2.0 × 10⁻⁶ kWh of electricity to treat 1 L of water. -3Electricity cost: 0.725 yuan / kWh. Since industrial electricity prices vary across the country, the average price in large and medium-sized cities during certain periods is used as the basis. Therefore, treating one ton of wastewater costs 2.12 yuan. This meets the low energy consumption requirement. Therefore, this invention is characterized by high efficiency, economy, and applicability.

[0039] Example 2: Example 2 is basically the same as Example 1, with the main difference being: A DC power supply with a voltage of 4V was applied, and the wastewater was immediately measured after the power supply was completed. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg were 84.25%, 86.73%, 78.92%, 61.89%, 64.32%, and 70.69%, respectively.

[0040] The operating voltage is 4V. According to the energy consumption formula, this system consumes 1.3 × 10⁻⁶ units of electricity to process 1L of water. -3 Electricity cost: Since industrial electricity prices vary across the country, the average price in large and medium-sized cities during certain periods is used as a basis: 0.725 yuan / kWh. Therefore, treating one ton of wastewater costs 0.94 yuan. This meets the low energy consumption requirement. Therefore, this invention is characterized by high efficiency, economy, and applicability.

[0041] Example 3: Example 3 is basically the same as Example 1, with the main difference being: The DC power supply was set to 8V, and the wastewater was immediately measured after the test. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg were 90.21%, 91.26%, 78.91%, 58.98%, 57.14%, and 81.82%, respectively.

[0042] The operating voltage is 8V. According to the energy consumption formula, this system consumes 1.3 × 10⁻⁶ units of electricity to process 1L of water. -3 Electricity cost: 0.725 yuan / kWh. Since industrial electricity prices vary across the country, the average price during peak hours in large and medium-sized cities is used as the basis. Therefore, treating one ton of wastewater would cost 3.27 yuan. This meets the low energy consumption requirement. Therefore, this invention is characterized by high efficiency, economy, and applicability.

[0043] Example 4: Example 3 is basically the same as Example 1, with the main difference being: A DC power supply with a voltage of 10V was applied, and the wastewater was immediately measured after the power supply was completed. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg were 84.11%, 86.76%, 71.41%, 52.38%, 50.74%, and 74.20%, respectively.

[0044] The operating voltage is 8V. According to the energy consumption formula, this system consumes 1.3 × 10⁻⁶ units of electricity to process 1L of water.-3 Electricity cost: 0.725 yuan / kWh (per unit of electricity). Since industrial electricity prices vary across the country, the average price in large and medium-sized cities during certain periods is used as the basis. Therefore, treating one ton of wastewater would cost 4.89 yuan. This meets the low energy consumption requirement. Therefore, this invention is characterized by high efficiency, economy, and applicability.

[0045] Example 5: (1) Inject 15L of heavy metal wastewater into a dynamic three-dimensional electrochemical reactor.

[0046] (2) Add 100 mg / L of K2S to the heavy metal wastewater and adjust the pH to 8.

[0047] (3) The aluminum anode plate and the ruthenium-iridium cathode plate were selected as the two electrode plates. The dimensions of both plates were 2.0cm×0.6cm×32cm (length×width×height). Before use, they were soaked in 10% dilute hydrochloric acid for 10 minutes.

[0048] (4) Install the aluminum electrode plate and the ruthenium-iridium electrode on both sides of the rotating shaft, keeping the distance between the electrode plates at 45 cm. Place the sludge residue in an ethanol solution, wash it with ultrasonic water at 100 watts, and then dry it at 65°C for 40 min. Subsequently, fill the space between the two electrode plates with 40 g of sludge residue. The effective area of ​​the two electrode plates is 80% of the total area.

[0049] (5) Connect the rotating shaft to the power supply (Note: the anode and cathode of the power supply are connected to the two sides of the rotating shaft respectively). The DC power supply applies a voltage of 6V and the power supply time is 100min.

[0050] (6) After the reaction in the electrolytic cell is completed for 100 minutes, the wastewater is injected into the reaction cell through a peristaltic pump for further treatment.

[0051] (7) Add 100 mg / L of chelating agent to the wastewater in the reaction tank, adjust the pH to between 9, turn on the power, and stir continuously for 20 min.

[0052] (8) Immediately after the event, the levels of various heavy metals in the wastewater were measured. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg were 92.56%, 92.53%, 84.70%, 72.57%, 70.67%, and 80.25%, respectively.

[0053] Example 6: Example 6 is basically the same as Example 5, with the main difference being: 30g of sludge was filled between the two electrode plates. After the process was completed, the levels of various heavy metals in the wastewater were measured immediately. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg were 87.63%, 89.95%, 87.29%, 64.15%, 69.26%, and 71.14%, respectively.

[0054] Example 7: Example 7 is basically the same as Example 1, with the main difference being: 100 mg / L of K2S was added to the heavy metal wastewater, and the pH was adjusted to 9. Immediately after the addition, the levels of various heavy metals in the wastewater were measured. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg were 97.15%, 98.12%, 94.98%, 75.02%, 77.68%, and 89.49%, respectively.

[0055] Example 8: Example 8 is basically the same as Example 1, with the main difference being: The electrode plates were kept 40 cm apart, and the various heavy metals in the wastewater were measured immediately after the process. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg were 97.85%, 97.17%, 94.51%, 75.64%, 78.09%, and 89.49%, respectively.

[0056] Example 9: Example 9 is basically the same as Example 1, with the main difference being: After applying a 6V DC power supply, the power-on time was increased to 120 minutes. Immediately after the power-on time, the various heavy metals in the wastewater were measured. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg reached 96.57%, 94.54%, 93.43%, 72.53%, 75.68%, and 87.49%, respectively.

[0057] Example 10: Example 10 is basically the same as Example 1, with the main difference being: After applying a 6V DC power supply, the power-on time was shortened to 90 minutes. Immediately after the power-on time, the various heavy metals in the wastewater were measured. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg reached 92.84%, 90.24%, 87.54%, 68.29%, 71.58%, and 84.28%, respectively.

[0058] Example 11: Example 11 is basically the same as Example 1, with the main difference being: 100 mg / L of chelating agent was added to the wastewater in the reaction tank, and the pH was adjusted to 7. Immediately after the reaction, the levels of various heavy metals in the wastewater were measured. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg reached 90.74%, 92.58%, 89.41%, 72.58%, 78.94%, and 84.25%, respectively.

[0059] Example 12: Example 12 is basically the same as Example 1, with the main difference being: 100 mg / L of chelating agent was added to the wastewater in the reaction tank, and the pH was adjusted to 10. Immediately after the reaction, the levels of various heavy metals in the wastewater were measured. The degradation efficiencies of Pb, Cd, As, Tl, Cu, and Hg reached 88.01%, 89.23%, 87.54%, 60.14%, 75.12%, and 85.67%, respectively.

[0060] Comparative Example 1: The sludge residue in Example 1 is omitted to form a two-dimensional reaction environment, and electricity is applied according to the operation method in Example 1.

[0061] Comparative Example 2: The deep treatment in Example 1 is omitted, and no chelating agent is used for deep treatment. Only a dynamic three-dimensional electrochemical reaction is carried out, and the energizer is applied according to the operation method in Example 1.

[0062] Comparative Example 3: The sludge residue and subsequent advanced treatment in Example 1 were omitted, and only the dynamic two-dimensional electrochemical reaction was carried out, and electricity was applied according to the operation method in Example 1.

[0063] Comparative Example 4: The dynamic three-dimensional electrochemical reaction device in Example 1 was configured as a traditional fixed three-dimensional electrochemical reaction device, and energized according to the operation method in Example 1.

[0064] The heavy metal wastewater was treated using the methods described in Examples 1-12 and Comparative Examples 1-4, and the results are as follows: parameter Pb Cd As Tl Cu Hg Example 1 97.46% 98.97% 95.26% 75.94% 77.27% 89.79% Example 2 84.25% 86.73% 78.92% 61.89% 64.32% 70.69% Example 3 90.21% 91.26% 78.54% 58.98% 57.14% 81.82% Example 4 84.11% 86.76% 71.41% 52.38% 50.71% 74.20% Example 5 92.56% 92.53% 84.70% 72.57% 70.67% 80.25% Example 6 87.63% 89.95% 87.29% 64.15% 69.26% 71.14% Example 7 97.15% 98.15% 94.98% 95.02% 77.68% 89.49% Example 8 97.85% 97.17% 94.51% 75.64% 78.09% 89.49% Example 9 96.57% 94.84% 93.43% 72.53% 75.68% 87.49% Example 10 92.84% 90.24% 87.54% 68.29% 71.58% 84.28% Example 11 90.74% 92.58% 89.41% 72.58% 78.94% 84.25% Example 12 88.01% 89.23% 87.54% 60.14% 75.12% 85.67% Comparative Example 1 77.92% 74.83% 65.92% 50.27% 50.73% 61.79% Comparative Example 2 56.27% 67.21% 48.91% 42.21% 41.92% 53.90% Comparative Example 3 47.69% 54.37% 32.97% 18.98% 35.14% 29.51% Comparative Example 4 71.30% 78.53% 69.875 51.29% 48.26% 49.70% As can be seen from the table above: Example 1 shows that dynamic three-dimensional electrode coupled flocculation has a significant impact on the degradation efficiency of various heavy metals in wastewater. Example 4 also shows that a decrease in the concentration of the chelating agent affects the degradation rate of various heavy metals in wastewater. Comparative Example 1 shows that the sludge in this application helps the electrode to achieve better conductivity; Comparative Example 2 shows that the addition of the chelating agent has a significant impact on the degradation of various heavy metal ions; Comparative Example 3 shows that the method in this application has a significant impact on the concentration of heavy metal ions removed; Comparative Example 4 shows that fixed electrodes cause electrode plate passivation, leading to a decrease in electrochemical reaction efficiency, thereby affecting the removal of heavy metal ions.

[0065] In summary, this application designs a dynamic rotating electrochemical device where the polarization behavior of the anode electrode plate exhibits the common characteristics of solubility in rotating electrodes, eliminating passivation under static conditions and accelerating the reaction of Cl at a certain rotation speed. - The diffusion of sulfides increases the lifespan of the electrode plates and reduces costs. A three-dimensional electrode is formed by the anode, cathode, and sludge filling the space between them. The sludge increases the collision probability with sulfides, enhancing the sludge's sweeping effect. Excess reagents remaining in the sludge can be reused, which helps resist shock loads from water quality and quantity during actual treatment. Furthermore, the sludge, due to its various metal components, increases current density, promoting better electrode conductivity and facilitating electrochemical coupling. Simultaneously, sulfides are used as the electrolyte. Ions in the solid sulfide electrolyte undergo redox reactions with water molecules, being oxidized to sulfate. Sulfates, under the combined excitation of the cathode and anode, generate sulfate radicals and highly oxidizing hydroxyl radicals, which are beneficial for the removal of heavy metal ions. Adding chelating agents for secondary deep treatment of wastewater allows small molecules in the solution to adsorb and form large molecules, while small particles bridge and combine to form larger particles, generating precipitates with relatively large molecular weights, thus achieving deep removal of heavy metals.

[0066] The dynamic three-dimensional electrode-flocculation coupling method for treating heavy metal wastewater is simple to operate, significantly reduces costs, improves economic efficiency, and demonstrates remarkable effectiveness in treating heavy metal ions. Therefore, the dynamic three-dimensional electrode-flocculation coupling device and the method for treating heavy metal wastewater using this device have excellent prospects for widespread application.

[0067] The above are merely preferred embodiments of the present invention.

Claims

1. A dynamic three-dimensional electrode flocculation coupled wastewater treatment device, characterized in that, The device includes an electrolytic cell, a reaction tank, a rotating shaft, a drive motor, an anode, and a cathode. The rotating shaft is connected to the output shaft of the drive motor and is located inside the electrolytic cell. A support is connected to the lower part of the rotating shaft. The anode and cathode are fixed at both ends of the support. Sludge is placed inside the electrolytic cell, and the anode and cathode are inserted into the sludge. The electrolytic cell is connected to a peristaltic pump and the reaction tank in sequence through pipes. A stirring device is installed inside the reaction tank.

2. A dynamic three-dimensional electrode flocculation coupled wastewater treatment method according to claim 1, characterized in that, Includes the following steps: S1: Inject the heavy metal wastewater into the electrolytic cell; S2: Add electrolytes to heavy metal wastewater and adjust the pH to between 8 and 9; S3: The two electrode plates should be soaked in an acid solution before use. S4; The sludge residue is placed in an ethanol solution, washed with ultrasonic water, dried, and then filled between the two electrode plates. S5: Connect the cathode and anode to the power supply. Apply a DC power supply voltage of 4-10V for 90-120 minutes. Before energizing, adjust the pH of the solution in the electrolytic cell to 9. S6: After the reaction in the electrolytic cell has lasted for 100 minutes, the wastewater is injected into the reaction cell through a peristaltic pump; S7: Add chelating agent to the wastewater in the reaction tank, adjust the pH to between 7 and 10, and stir for 20 minutes.

3. The dynamic three-dimensional electrode flocculation coupled wastewater treatment method according to claim 2, characterized in that, The acid solution includes one or a mixture of two of hydrochloric acid and sulfuric acid, and the volume concentration of the acid solution is 5-15%.

4. The dynamic three-dimensional electrode flocculation coupled wastewater treatment method according to claim 2, characterized in that, Soaking time in S3 is 10-15 minutes, and the distance between electrode plates is kept at 40-45 cm.

5. The dynamic three-dimensional electrode flocculation coupled wastewater treatment method according to claim 2, characterized in that, The anode is a carbon-based electrode, a metal electrode, a metal composite load electrode, or a ceramic electrode, and the cathode is a ruthenium-iridium electrode. The area of ​​the anode and cathode inserted below the liquid surface in the electrolytic cell is 75-85% of the total surface area of ​​the anode and the cathode.

6. The dynamic three-dimensional electrode flocculation coupled wastewater treatment method according to claim 2, characterized in that, The concentration of the chelating agent is 200-300 mg / L.

7. The dynamic three-dimensional electrode-flocculation coupled wastewater treatment method according to claim 2, characterized in that, The electrolyte is a sulfide. Preferably, the persulfate includes one or a mixture of two of K2S and Na2S. The concentration of the sulfide in the solution to be electrolyzed in the electrolytic cell is 80-120 mg / L.

8. The dynamic three-dimensional electrode flocculation coupled wastewater treatment method according to claim 7, characterized in that, The dielectric is K2S, and 0.1g of K2S is added per liter of wastewater.

9. The dynamic three-dimensional electrode flocculation coupled wastewater treatment method according to claim 2, characterized in that, In step S4, the ultrasonic power is 80-100 watts; the ultrasonic water washing time is 10-15 minutes, and drying is carried out at a temperature of 62-70℃ for 30-45 minutes.

10. The dynamic three-dimensional electrode flocculation coupled wastewater treatment method according to claim 2, characterized in that, The amount of sludge added to each liter of the industrial wastewater is 35-40g.

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