An apparatus and method for dechlorination of wastewater by electrooxidation enhanced by ultrasonic degassing

Abstract

The application discloses an ultrasonic degassing reinforced electro-oxidation wastewater chlorine removal device and method, and belongs to the technical field of electrochemical water treatment. The electro-oxidation wastewater chlorine removal device comprises a reaction tank and an ultrasonic generator for applying ultrasonic action to wastewater in the reaction tank; the reaction tank is installed with a chlorine evolution anode and a titanium-based cathode; the chlorine evolution anode comprises a pure titanium base body, and the pure titanium base body is sequentially coated with a noble metal oxide coating and a Bi5O7Cl coating from inside to outside. The application can improve the chlorine evolution efficiency by preparing a high-activity chlorine evolution anode; the chlorine gas generated by electro-oxidation can be discharged in time through the action of ultrasonic waves, so that the chlorine gas is prevented from being redissolved and converted into chloride ions again; meanwhile, the ultrasonic waves can also act on water molecules and oxygen generated by the oxygen evolution side reaction, so that various active species are generated, and the chloride ions are converted into chlorine gas. The application can significantly improve the removal rate of chloride ions, improve the current efficiency, reduce the risk of electrode pollution, and prolong the service life of the electrode.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrochemical water treatment, and particularly relates to a device and method for removing chlorine from wastewater by electro-oxidation with ultrasonic degassing reinforcement. BACKGROUND

[0002] Chlorine-containing wastewater mainly comes from metallurgy, mining, chemical industry, machinery manufacturing, food processing, textile, and daily life washing and disinfection product use. The concentration of chloride ions in industrial wastewater is generally higher than 2000 mg / L, and the concentration of chloride ions in metallurgical wastewater is even as high as 10000 mg / L. High concentration of chloride ions can cause corrosion and fouling of pipeline facilities, and if the chlorine-containing wastewater is not properly treated, it will cause soil salinization and further lead to quality degradation when discharged into the environment.

[0003] At present, the methods for removing chloride ions from wastewater mainly include chemical precipitation, ion exchange, membrane separation, and oxidation. The chemical precipitation method mainly adds a precipitant to react with chloride ions to form a precipitate to remove chloride ions. The core mechanism of the ion exchange method is to exchange the chloride ions in water with an ion exchanger to remove the chloride ions. The membrane separation method mainly separates water from other species through screening and charge repulsion. The oxidation method mainly uses ozone or active species generated by persulfate to oxidize chloride ions to produce chlorine gas, thereby removing chloride ions.

[0004] However, the chemical precipitation method and the oxidation method involve the addition of chemical agents, and the generated precipitate needs to be further disposed. The ion exchange method and the membrane separation method only transfer and enrich the chloride ions, and the used ion exchanger and membrane concentrate still need to be further treated. In contrast, the electro-oxidation method uses the direct and indirect oxidation of the anode to convert chloride ions into chlorine gas, without the need for additional chemical agents. It is simple and easy to operate, and the industrial wastewater with high salt content has good conductivity, so the electro-oxidation method has obvious advantages.

[0005] However, the commonly used noble metal oxide anode has the problem of low chlorine evolution efficiency in the application of electro-oxidation for removing chlorine. In addition, the electro-oxidation for removing chlorine has problems such as oxygen evolution side reactions and chlorine gas redissolution, which reduce the current efficiency and the removal rate of chloride ions. Therefore, it is necessary to prepare anode materials with high chlorine evolution activity and to improve and optimize the electro-oxidation process for removing chlorine to solve the above problems. SUMMARY

[0006] To solve the above problems, the present application provides a device and method for removing chlorine from wastewater by electro-oxidation with ultrasonic degassing reinforcement. By preparing a high-activity chlorine evolution anode, the chlorine evolution efficiency is improved. Chlorine gas generated by electro-oxidation is promptly discharged by ultrasonic waves, avoiding the redissolution of chlorine gas and its conversion back into chloride ions. At the same time, ultrasonic waves can also act on water molecules and oxygen generated by oxygen evolution side reactions, thereby generating various active species and converting chloride ions into chlorine gas.

[0007] To achieve the above object, the technical scheme adopted by the present application is:

[0008] The first object of the present application is to provide an ultrasonic degassing enhanced electro-oxidation wastewater dechlorination device, which comprises a reaction tank and an ultrasonic generator for applying ultrasonic effect to wastewater in the reaction tank, an ultrasonic working head of the ultrasonic generator is inserted into the reaction tank or fixed to the outer wall of the reaction tank; the reaction tank is provided with a gas outlet; the reaction tank is connected with a gas absorption tank through the gas outlet; the gas absorption tank has an absorption liquid for absorbing chlorine gas, and the absorption liquid is saturated limewater or sodium hydroxide solution; the reaction tank is connected with a peristaltic pump, specifically, a hose can be connected in the reaction tank, and the peristaltic pump is installed on the hose, so as to stir the water body in the reaction tank through the peristaltic pump, so that various chemical reactions are more uniform, thereby improving the water treatment effect.

[0009] A chlorine evolution anode and a titanium-based cathode are installed in the reaction tank; the chlorine evolution anode and the titanium-based cathode are connected with a power supply; the chlorine evolution anode comprises a pure titanium substrate, and the pure titanium substrate is sequentially coated with a noble metal oxide coating and a Bi5O7Cl coating from inside to outside; the titanium-based cathode can be a pure titanium cathode.

[0010] As a preferred technical scheme, the preparation method of the chlorine evolution anode comprises the following steps:

[0011] (1) providing a pure titanium substrate with a noble metal oxide coating on the surface; further preferably, the noble metal oxide coating is an oxide coating containing ruthenium and iridium (such as RuO2, IrO2, etc.).

[0012] (2) adding bismuth salt to a solvent containing ethylene glycol, oleylamine and ethanol to obtain a bismuth salt solution; preferably, the bismuth salt is bismuth nitrate, bismuth sulfate or bismuth chloride; ethylene glycol in the bismuth salt solution has good solubility and stability, and can promote uniform dispersion of the bismuth salt; oleylamine can prevent particle agglomeration and control the morphology of the material; at the same time, ethylene glycol and oleylamine can provide an alkaline environment for the preparation of Bi5O7Cl; ethanol as a cosolvent can improve the solubility of polar reagents and accelerate mass transfer; the specific operation method is as follows: first, mix ethylene glycol and oleylamine in a volume ratio of 1:1, then add bismuth salt to dissolve, and then add ethanol and stir uniformly to obtain the bismuth salt solution; dropwise add potassium chloride solution to the bismuth salt solution, and heat at a temperature of 60-80 ℃ to obtain a precipitate Bi5O7Cl; the preparation reaction equation of Bi5O7Cl is: .

[0013] Bi5O7Cl is dispersed in a mixed solution of water, isopropyl alcohol and Nafion, the obtained mixture is coated on the surface of a pure titanium substrate with a noble metal oxide coating, and is dried under an infrared lamp to obtain a chlorine evolution anode.

[0014] A second object of the present application is to provide a method for removing chlorine from wastewater by electro-oxidation and ultrasonic degassing, which is performed by using the device for removing chlorine from wastewater by electro-oxidation according to the first object.

[0015] The wastewater to be treated is injected into the reaction tank;

[0016] The chlorine ions in the wastewater are converted into chlorine gas by the chlorine evolution anode, and the ultrasonic generator is used to improve the removal rate of the chlorine ions. 2 The current density of the power supply is preferably 10-200 mA / cm2, the input power of the ultrasonic generator is preferably 50-150 W, and the ultrasonic frequency is preferably 10-100 kHz.

[0017] The generated chlorine gas is collected and treated, specifically, the chlorine gas is discharged into a gas absorption tank containing a gas absorption liquid through a gas outlet, and the chlorine gas is treated by saturated limewater or sodium hydroxide solution.

[0018] The core of the device and method for removing chlorine from wastewater by ultrasonic degassing enhanced electro-oxidation provided by the application is that: (1) the chlorine evolution anode has excellent chlorine evolution efficiency under the joint action of Bi5O7Cl coating and noble metal oxide coating, which can improve the chlorine removal efficiency of electro-oxidation; (2) the chlorine evolution anode converts chloride ions into chlorine gas through direct oxidation, at the same time, the anode electrolyzes water to generate hydroxyl radicals, and the hydroxyl radicals can also oxidize chloride ions to generate chlorine gas; (3) the ultrasonic wave is applied to wastewater to form cavitation bubbles, and the generated chlorine gas enters the cavitation bubbles, and the small bubbles quickly change into large bubbles and leave the water surface, that is, the ultrasonic wave accelerates the discharge of chlorine gas, avoiding its redissolution to be converted into chloride ions again; (4) the ultrasonic wave acts on water and oxygen generated by the oxygen evolution side reaction to generate various active substances and oxidize chloride ions to generate chlorine gas, thereby improving the current efficiency of the conversion of chloride ions into chlorine gas; (5) at the same time, the ultrasonic wave can increase the shear force of water, shorten the residence time of the bubbles generated on the electrode surface on the electrode surface, and reduce the detachment diameter of the bubbles, thereby improving the utilization rate of the active sites on the electrode surface and improving the treatment efficiency; (6) in addition, the high-frequency vibration of the ultrasonic wave can inhibit the adhesion of pollutants on the electrode surface, and can also peel off the deposited pollutants, that is, the ultrasonic wave can reduce the risk of electrode pollution, improve the treatment efficiency, and prolong the service life of the electrode.

[0019] The related chemical reactions involved in the electro-oxidation process of the application are as follows:

[0020] Anode direct oxidation to remove chloride ions:

[0021]

[0022]

[0023] Anode generates hydroxyl radicals to remove chloride ions:

[0024]

[0025]

[0026]

[0027] Chlorine gas is redissolved to be converted into chloride ions again:

[0028]

[0029]

[0030] Ultrasonic wave acts on water and reacts with oxygen generated by anode oxygen evolution side reaction to generate active species to remove chloride ions:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] In summary, compared with the prior art, the advantages of the present application are:

[0039] 1. Cl in the Bi5O7Cl coating of the anode - is oxidized to under the excitation of the anode electric field, and further generates chlorine gas, while the Bi5O7Cl lacking Cl - has a strong binding force with Cl - in the solution, and can generate Bi5O7Cl again, so the compensation of Cl - can occur rapidly, which ensures that can be continuously generated without destroying the structure of Bi5O7Cl; at the same time, the binding ability between Cl - in the solution and Bi5O7Cl lacking Cl - is much higher than the adsorption of Cl - on the surface of the ordinary anode, so the generation of can be promoted, and the chlorine evolution efficiency is improved; moreover, the Bi5O7Cl coating can shield the oxygen evolution sites on the surface of the noble metal oxide coating, inhibit the oxygen evolution side reaction, and further improve the current efficiency of the anode chlorine evolution.

[0040] 2. Since chlorine gas is easily soluble in water and can react with water to ultimately convert into chloride ions, the chlorine gas generated in the process of electro-oxidation dechlorination will reduce the removal rate of chloride ions and the current efficiency due to redissolution. The present application uses the degassing effect of ultrasound to accelerate the discharge of chlorine gas generated in the process of electro-oxidation from the wastewater, thereby effectively alleviating the problem of chlorine gas redissolution, and improving the current efficiency and the removal rate of chloride ions.

[0041] 3. In the process of electro-oxidation, while chloride ions lose electrons and are oxidized at the anode, hydroxyl ions also lose electrons and generate oxygen at the anode, and the competition of the oxygen evolution side reaction reduces the current efficiency of electro-oxidation dechlorination. The ultrasound introduced in the present application can act on the oxygen generated in the oxygen evolution side reaction, and convert it into active substances, which further oxidize chloride ions to generate chlorine gas, thereby realizing the "waste into treasure" of oxygen, improving the current efficiency and the removal rate of chloride ions.

[0042] 4. The ultrasound introduced in this invention can promote the gas to leave the electrode surface and reduce the detachment diameter of the bubbles, thereby improving the utilization rate of the chlorine-evolving active sites on the electrode surface and increasing the processing efficiency.

[0043] 5. The ultrasound introduced in this invention can inhibit the adhesion of contaminants to the electrode surface and remove deposited contaminants, thereby reducing the risk of electrode contamination, improving processing efficiency, and extending the service life of the electrode.

[0044] 6. Compared with conventional electro-oxidation dechlorination technology, this invention can significantly improve the chloride ion removal rate, increase current efficiency, reduce the risk of electrode contamination, and extend the service life of the electrode. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the ultrasonic degassing enhanced electro-oxidation wastewater dechlorination device of the present invention;

[0046] Figure 2 This is another structural schematic diagram of the ultrasonic degassing enhanced electro-oxidation wastewater dechlorination device of the present invention;

[0047] Figure 3 The diagram shows the bubble detachment diameter and chlorine gas discharge effect under (a) no ultrasound and (b) ultrasound conditions.

[0048] Figure 4 This is a schematic diagram comparing the chlorine evolution process of a conventional anode (a) and the chlorine evolution anode (b) in this invention.

[0049] Figure labels: 1-Reaction tank; 2-Peristaltic pump; 3-Power supply; 4-Ultrasonic generator; 5-Gas absorption tank; 6-Chlorine anode; 7-Pure titanium cathode; 8-Ultrasonic working head; 9-Gas outlet. Detailed Implementation

[0050] The present invention will be further described below with reference to embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0051] In addition, unless otherwise specified, the preparation processes in the following embodiments are all conventional methods in the prior art, and therefore will not be described in detail; the raw materials used in this invention are all commercially available products.

[0052] Example 1

[0053] A schematic diagram of an ultrasonically degassing-enhanced electro-oxidation wastewater dechlorination device is shown below. Figure 1 and Figure 2The device comprises a reaction tank 1, a peristaltic pump 2, a power supply 3, an ultrasonic generator 4, and a gas absorption tank 5. The reaction tank 1 is provided with a chlorine evolution anode 6 and a pure titanium cathode 7 connected with the power supply. The ultrasonic generator 4 is connected with an ultrasonic working head 8 which is inserted into the reaction tank or fixed to the outer wall of the reaction tank. The reaction tank 1 is provided with a gas outlet 9 connected with the gas absorption tank 5. Figure 1 The ultrasonic working head is inserted into the reaction tank, Figure 2 The ultrasonic working head is fixed to the outer wall of the reaction tank.

[0054] Example 2

[0055] The method comprises the following steps:

[0056] The wastewater to be treated is injected into the reaction tank, and the peristaltic pump is started.

[0057] The chlorine evolution anode and the titanium-based cathode are powered by the power supply, and the chlorine evolution anode is used to convert the chloride ions in the wastewater into chlorine gas. At the same time, the ultrasonic generator is started to apply ultrasonic effect to the wastewater to improve the removal rate of chloride ions.

[0058] The generated chlorine gas is collected and treated.

[0059] The specific operation parameters and treatment effects are as follows:

[0060] The concentration of the chlorine-containing simulated wastewater is 500 mg / L.

[0061] The ultrasonic input power is 50 W.

[0062] The ultrasonic frequency is 20 kHz.

[0063] The current density is 50 mA / cm 2 ;

[0064] The treatment time is 10 min.

[0065] The treatment effect is that after treatment, the concentration of chloride ions is 48 mg / L, and the removal rate is 90.4%.

[0066] The preparation method of the chlorine evolution anode used in Example 2 is as follows:

[0067] (1) A pure titanium substrate with a noble metal oxide coating on the surface is provided. In a specific example, a commercial ruthenium-iridium-titanium electrode is selected, which is composed of an industrial pure titanium substrate and a noble metal oxide coating. The coating material contains ruthenium and iridium oxides, has high catalytic activity, can reduce the overpotential of chlorine evolution and oxygen evolution, and improve the current efficiency. In wastewater treatment, chloride ions are converted into chlorine gas through direct oxidation. For those skilled in the art, similar purposes can also be achieved by coating other noble metal oxide coatings on the surface of the pure titanium electrode.

[0068] (2) Preparation of Bi5O7Cl coating, comprising the following steps:

[0069] A 7 mmol / L bismuth nitrate solution A was prepared using ethylene glycol and oleylamine as solvents (volume ratio 1:1), continuously stirred for 30 min, and heated to 60°C;

[0070] Take 150 mL of bismuth nitrate solution A, add 50 mL of anhydrous ethanol, continuously stir for 20 min, and obtain bismuth nitrate solution B;

[0071] A 20 mmol / L potassium chloride solution was prepared using deionized water as a solvent; 50 mL of the potassium chloride solution was added dropwise to the bismuth nitrate solution B, continuously stirred and heated at 60°C for 24 h; the precipitate was collected by centrifugation at a speed of 6000 rpm, and the precipitate was washed with chloroform, anhydrous ethanol, and deionized water several times, and finally dried at 60°C under vacuum for 24 h to obtain the material Bi5O7Cl;

[0072] 10 mg of Bi5O7Cl was dispersed in 1400 μL of deionized water, 450 μL of isopropanol, and 100 μL of a mixed solution of Nafion (5 wt%), and an ultrasonic treatment was performed to obtain a spraying solution, which was finally sprayed on the surface of a pure titanium substrate with a noble metal oxide coating, and dried under an infrared lamp to obtain a chlorine evolution anode.

[0073] Example 3:

[0074] The chlorine evolution anode prepared by the same method as in Example 2 was used for the ultrasonic degassing enhanced electro-oxidation of wastewater to remove chlorine, and the specific operation parameters and treatment effects are as follows:

[0075] Chlorine-containing simulated wastewater concentration: 2000 mg / L;

[0076] Ultrasonic input power: 60 W;

[0077] Ultrasonic frequency: 40 kHz;

[0078] Current density: 100 mA / cm 2 ;

[0079] Treatment time: 20 min;

[0080] Treatment effect: After treatment, the concentration of chloride ions was 92 mg / L, and the removal rate was 95.4%.

[0081] Comparative Example 1:

[0082] Similar to Example 3, except that no electric field was applied. The specific operation parameters and treatment effects are as follows:

[0083] Chlorine-containing simulated wastewater concentration: 2000 mg / L;

[0084] Ultrasonic input power: 60 W;

[0085] Ultrasonic frequency: 40 kHz;

[0086] Current density: 0 mA / cm 2 ;

[0087] Treatment time: 20 min;

[0088] Treatment effect: After treatment, the concentration of chloride ion was 1880 mg / L, and the removal rate was 6%.

[0089] Comparative Example 2:

[0090] Similar to Example 3, except that no ultrasonic was applied. The specific operation parameters and treatment effects are as follows:

[0091] Chlorine-containing simulated wastewater concentration: 2000 mg / L;

[0092] Ultrasonic input power: 0 W;

[0093] Ultrasonic frequency: 0 kHz;

[0094] Current density: 100 mA / cm 2 ;

[0095] Treatment time: 20 min;

[0096] Treatment effect: After treatment, the concentration of chloride ion was 1450 mg / L, and the removal rate was 27.5%.

[0097] From the results of Comparative Example 2, it can be seen that under the condition of no ultrasonic application, even if other process parameters are the same as Example 3, the removal rate of chloride ion is very low, far lower than the result in Example 3. In order to intuitively present the effect of ultrasonic in removing chloride ion, the following is explained, Figure 3 Figure 3 are (a) without ultrasonic and (b) with ultrasonic. From Figure 3 it can be seen that under the action of ultrasonic, the gas can be promoted to leave the electrode surface, and the diameter of the bubble is reduced, the utilization rate of the active site of the electrode surface for chlorine evolution is improved, and the treatment efficiency is improved; in addition, the ultrasonic wave applied to the wastewater forms cavitation bubbles, and the chlorine gas produced enters the cavitation bubbles, and the small bubbles quickly change into large bubbles and leave the water surface, that is, the ultrasonic wave accelerates the discharge of chlorine gas, avoiding its redissolution and re-conversion into chloride ion.

[0098] Comparative Example 3:

[0099] Similar to Example 3, except that the anode was a commercial ruthenium-iridium-titanium electrode. ​

[0100] The specific operation parameters and treatment effects are as follows:

[0101] Chlorine-containing simulated wastewater concentration: 2000 mg / L;

[0102] Ultrasonic input power: 60 W;

[0103] Ultrasonic frequency: 40 kHz;

[0104] Current density: 100 mA / cm 2 ;

[0105] Treatment time: 20 min;

[0106] Treatment effect: After treatment, the concentration of chloride ions is 312 mg / L, and the removal rate is 84.4%.

[0107] From the results of Comparative Example 3, it can be seen that if the chlorine evolution anode does not contain a Bi5O7Cl coating, the removal rate of chloride ions will be lower than that of Example 3. Figure 4 The schematic diagram of the chlorine evolution process of the ordinary anode (a) and the chlorine evolution anode (b) in the present application is shown in Figure 1. Figure 4 It can be seen that the chlorine evolution anode containing a Bi5O7Cl coating used in the present application is more prone to Cl - In combination, it can promote the generation of Cl‧ and improve the chlorine evolution efficiency.

[0108] Example 4:

[0109] In this example, the chlorine evolution anode prepared by the same method as in Example 2 is used for the chlorine removal process of wastewater by ultrasonic degassing enhanced electro-oxidation, and the specific operation parameters and treatment effects are as follows:

[0110] Chlorine-containing simulated wastewater concentration: 8000 mg / L;

[0111] Ultrasonic input power: 100 W;

[0112] Ultrasonic frequency: 60 kHz;

[0113] Current density: 150 mA / cm 2 ;

[0114] Treatment time: 30 min;

[0115] Treatment effect: After treatment, the concentration of chloride ions is 132 mg / L, and the removal rate is 98.4%

[0116] Obviously, the described examples are part of the embodiments of the present application, but not all. Based on the examples in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

Claims

1. An ultrasonic degassing enhanced electro-oxidation dechlorination device for wastewater, characterized in that: The device comprises a reaction tank and an ultrasonic generator for applying ultrasonic effect to wastewater in the reaction tank; the reaction tank is provided with a gas outlet; the reaction tank is installed with a chlorine-evolving anode and a titanium-based cathode; the chlorine-evolving anode and the titanium-based cathode are connected with a power supply; the chlorine-evolving anode comprises a pure titanium substrate, which is coated with a noble metal oxide coating and a Bi5O7Cl coating from inside to outside.

2. The ultrasonic deaeration enhanced electrooxidation wastewater chlorine removal device of claim 1, wherein: The preparation method of the chlorine-evolving anode comprises the following steps: (1) providing a pure titanium substrate with a noble metal oxide coating on the surface; (2) adding bismuth salt into a solvent containing ethylene glycol, oleylamine and ethanol to obtain a bismuth salt solution; adding potassium chloride solution drop by drop into the bismuth salt solution and heating at a temperature of 60-80 ℃ to obtain a precipitate Bi5O7Cl; dispersing Bi5O7Cl in a mixed solution of water, isopropyl alcohol and Nafion, coating the obtained mixture on the surface of the pure titanium substrate with the noble metal oxide coating, and drying under an infrared lamp to obtain the chlorine-evolving anode.

3. The ultrasonic deaeration enhanced electrooxidation wastewater chlorine removal device of claim 2, wherein: In step (1), the noble metal oxide coating is an oxide coating containing ruthenium and iridium.

4. The ultrasonic deaeration enhanced electrooxidation wastewater chlorine removal device of claim 2, wherein: In step (2), the bismuth salt is bismuth nitrate, bismuth sulfate or bismuth chloride.

5. The ultrasonic deaerated enhanced electrooxidation wastewater chlorine removal device according to any one of claims 1 to 4, characterized in that: The reaction tank is connected with a gas absorption tank; the gas absorption tank is connected with the gas outlet of the reaction tank.

6. The ultrasonic deaeration enhanced electrooxidation wastewater chlorine removal device of claim 5, wherein: The gas absorption tank is provided with an absorption liquid for absorbing chlorine; the absorption liquid is saturated limewater or sodium hydroxide solution.

7. The ultrasonic deaerated enhanced electrooxidation wastewater chlorine removal device according to any one of claims 1 to 4, characterized in that: The ultrasonic generator is connected with an ultrasonic working head, which is inserted into the reaction tank or fixed to the outer wall of the reaction tank.

8. The ultrasonic deaerated enhanced electrooxidation wastewater chlorine removal device according to any one of claims 1 to 4, characterized in that: The reaction tank is connected with a peristaltic pump.

9. A method for dechlorination of electro-oxidized wastewater by ultrasound degassing intensification, characterized by that: The method is performed by using the device for removing chlorine from wastewater by electro-oxidation according to any one of claims 1-8. The method comprises the following steps: injecting wastewater to be treated into the reaction tank; supplying power to the chlorine-evolving anode and the titanium-based cathode by the power supply, and converting chloride ions in the wastewater into chlorine by the chlorine-evolving anode; at the same time, improving the removal rate of chloride ions by applying ultrasonic effect to the wastewater by the ultrasonic generator; collecting and treating the generated chlorine.

10. The method of dechlorination of electro-oxidized wastewater according to claim 9, characterized in that: The current density of the power supply is 10-200 mA / cm 2 The input power of the ultrasonic generator is 50-150 W, and the ultrasonic frequency is 10-100 kHz.

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