CN111115761B - Electrochemical reaction device and method for synchronously removing total nitrogen in electroplating wastewater - Google Patents

Electrochemical reaction device and method for synchronously removing total nitrogen in electroplating wastewater Download PDF

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CN111115761B
CN111115761B CN201911336075.6A CN201911336075A CN111115761B CN 111115761 B CN111115761 B CN 111115761B CN 201911336075 A CN201911336075 A CN 201911336075A CN 111115761 B CN111115761 B CN 111115761B
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冒冉
孙拓
朱海洋
赵旭
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Research Center for Eco Environmental Sciences of CAS
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Abstract

The invention provides an electrochemical reaction device and method for synchronously removing total nitrogen in electroplating wastewater, belonging to the technical field of electrochemistry. The electrochemical reaction device comprises a reactor; at least one cathode plate disposed within the reactor; at least one anode plate disposed within the reactor; the negative plate and the positive plate are connected with an external direct current power supply; according to the concentration of ammonia nitrogen and organic nitrogen in the electroplating wastewater to be treated and the anodic oxidation reaction rate, the concentration of nitrate nitrogen and the cathodic reduction reaction rate, the number of the anode plates and the number of the cathode plates are correspondingly increased or decreased. The electrochemical reaction device for synchronously removing the total nitrogen in the electroplating wastewater is mainly used in the field of the electroplating wastewater, the total nitrogen removal rate can reach 99 percent, the energy and the time are saved, and the electrochemical reaction device is not influenced by the concentration of the electroplating wastewater, the fluctuation of water quality, the poison of heavy metals, the high salinity and the like.

Description

Electrochemical reaction device and method for synchronously removing total nitrogen in electroplating wastewater
Technical Field
The invention belongs to the technical field of electrochemistry, and particularly relates to an electrochemical reaction device and method for synchronously removing total nitrogen in electroplating wastewater.
Background
With the rapid development of industrialization in China, electroplating is widely applied to the fields of machinery manufacturing, electronics and the like as an intermediate matching link technology. However, in the electroplating process, waste bath solution, plating waste water such as cleaning water of plated parts, etc. are generated, and if the waste bath solution is not effectively treated, serious environmental pollution is caused.
The electroplating wastewater has more complex wastewater components and more prominent nitrogen pollution problem due to different processes and plating seeds. The nitrogen in the electroplating wastewater mainly exists in the forms of nitrate nitrogen, ammonia nitrogen and organic nitrogen. In the chemical nickel plating process, ammonia water used as a pH buffering agent, ammonium chloride used in the alkali type zinc plating process and the like can generate ammonia nitrogen pollutants; organic amine complexing agents are added into different plating seeds in the electroplating process as required to generate organic nitrogen pollutants; nitric acid is used for chemical polishing and pre-treatment of some special plating species, producing nitrate nitrogen contaminants.
The conventional method for removing the total nitrogen in the electroplating wastewater is a biochemical method, specifically, organic nitrogen is converted into ammonia nitrogen through ammoniation, the ammonia nitrogen is converted into nitrate nitrogen through nitrification, and the nitrate nitrogen is finally converted into nitrogen through denitrification. In addition, the total nitrogen removal method is a stripping method, but the stripping method can only remove ammonia nitrogen and has no effect on nitrate nitrogen.
In recent years, electrochemical techniques have been attracting attention because of their advantages such as wide water quality application range. However, the electrochemical reaction is used for removing total nitrogen in the electroplating wastewater due to different chemical reaction rates of the cathode and the anode, and can not synchronously complete the anodic oxidation for removing ammonia nitrogen and organic nitrogen and the cathodic reduction for removing nitrate nitrogen, so that the total treatment time is long and the energy consumption is high.
Disclosure of Invention
The invention provides an electrochemical reaction device and method for synchronously removing total nitrogen in electroplating wastewater.
The invention provides an electrochemical reaction device for synchronously removing total nitrogen in electroplating wastewater,
comprises a reactor;
at least one cathode plate disposed within the reactor;
at least one anode plate disposed within the reactor;
the negative plate and the positive plate are connected with an external direct current power supply;
according to the concentration of ammonia nitrogen and organic nitrogen in the electroplating wastewater to be treated and the anodic oxidation reaction rate, the concentration of nitrate nitrogen and the cathodic reduction reaction rate, the number of the anode plates and the number of the cathode plates are correspondingly increased or decreased.
Furthermore, the anode plate is a titanium ruthenium mesh electrode; the negative plate is a novel three-dimensional nitrogen-doped carbon-loaded foam copper electrode.
Further, the cathode plate and the anode plate have the same shape.
Furthermore, the cathode plate and the anode plate are arranged in parallel.
Further, the number ratio of the cathode plates to the anode plates is 1:4-4: 1; preferably, the number ratio of the cathode plates to the anode plates is 1:1 to 4: 1.
The invention also provides a method for removing the total nitrogen in the electroplating wastewater by using the electrochemical reaction device, which comprises the following steps:
introducing the electroplating wastewater into a reactor, and applying current by an external direct current power supply.
Further, persulfate is added into the reactor, so that the molar ratio of the organic nitrogen to the persulfate is 1: 1-1: 10.
Further, the density of the applied current is 1-20mA/cm2(ii) a Preferably, the density of the applied current is 3-10mA/cm2。
Compared with the prior art, the invention has the following advantages:
the electrochemical reaction device and the method for synchronously removing the total nitrogen in the electroplating wastewater have the advantages of simple and reasonable structural design, convenient operation, high speed of catalytic reduction of nitrate nitrogen by the cathode, energy and time saving, and no influence of electroplating wastewater concentration, water quality fluctuation, heavy metal toxicity, high salinity and the like, and the total nitrogen removal rate can reach 99%.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic diagram of a reactor according to an embodiment of the present invention;
FIG. 2(a) is a transmission electron micrograph of nitrogen-doped carbon (inset is selected area electron diffraction pattern); FIG. 2(b) is a scanning electron microscope image of a three-dimensional nitrogen-doped carbon-loaded copper foam electrode and an energy spectrum distribution image of copper, carbon and nitrogen.
Reference numerals:
1. a cathode plate; 2. an anode plate; 3. a direct current power supply; 4. a reactor.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The embodiment of the invention provides an electrochemical reaction device for synchronously removing total nitrogen in electroplating wastewater,
comprises a reactor;
at least one cathode plate 1 disposed within the reactor 4;
at least one anode plate 2 disposed within the reactor 4;
the negative plate 1 and the positive plate 2 are connected with an external direct current power supply 3;
according to the concentration of ammonia nitrogen and organic nitrogen in the electroplating wastewater to be treated, the anodic oxidation reaction rate, the nitrate nitrogen concentration and the cathodic reduction reaction rate, the number of the anode plates 1 and the number of the cathode plates 2 are correspondingly adjusted.
In the electroplating wastewater treatment process of the electrochemical reaction device provided by the embodiment of the invention, the cathode reduces nitrate nitrogen through direct electron reduction and indirect active atom hydrogen reduction, and the anode oxidizes ammonia nitrogen and organic nitrogen through electrooxidation and electroproduction of active chlorine (HClO/ClO-). Because the reduction rate of the nitrate nitrogen of the cathode is slower than the oxidation rate of the ammonia nitrogen of the anode, and the concentrations of the nitrate nitrogen, the ammonia nitrogen and the organic nitrogen in the electroplating wastewater to be treated are different, the proportion and the quantity of the cathode plate and the anode plate are correspondingly adjusted, thereby realizing the synchronous removal of the total nitrogen by the cathode and the anode.
The electrochemical reaction device for synchronously removing the total nitrogen in the electroplating wastewater provided by the embodiment of the invention has simple and reasonable structural design and convenient operation, and can adjust the proportion and the number of the cathode plate and the anode plate according to the requirement, thereby realizing the simultaneous removal of nitrate, ammonia nitrogen, organic nitrogen and the like in the electroplating wastewater, saving energy and time, and achieving the total nitrogen removal rate of 99 percent.
Furthermore, the anode plate is a titanium ruthenium mesh electrode; the negative plate is a novel three-dimensional nitrogen-doped carbon-loaded foam copper electrode. In the embodiment of the invention, the cathode plate is a three-dimensional nitrogen-doped carbon-loaded foamy copper cathode, and the anode plate is a titanium ruthenium mesh anode, so that the collocation is more suitable for efficiently removing the total nitrogen in the electroplating wastewater.
Specifically, the three-dimensional nitrogen-doped carbon-supported foamy copper cathode has excellent electron transfer performance and catalytic active sites, so that the three-dimensional nitrogen-doped carbon-supported foamy copper cathode has excellent electrocatalytic reduction activity, nitrate can be efficiently reduced and converted into ammonia nitrogen and partial nitrogen, the titanium ruthenium mesh anode has excellent chlorine evolution activity, chloride ions in waste water can be oxidized into active chlorine, the active chlorine can rapidly convert the ammonia nitrogen generated by the cathode and the ammonia nitrogen in the waste water into nitrogen, and organic nitrogen is decomposed into the ammonia nitrogen or nitrate nitrogen and further removed. Due to the efficient synergistic cooperation of cathode reduction and anode oxidation, the total nitrogen removal rate is up to more than 99%.
Therefore, the embodiment of the invention efficiently electrocatalytically reduces nitrate nitrogen to be converted into ammonia nitrogen and nitrogen gas through the three-dimensional nitrogen-doped carbon-loaded foamy copper cathode, and removes the ammonia nitrogen and organic nitrogen through the electro-oxidation of the titanium ruthenium network and the electroproduction active oxychlorination, so that the total nitrogen in the system is synergistically removed, and the total nitrogen removal rate is greatly improved. The electrode material has high activity, and the leaching amount of cathode copper is less than 0.1 mg/L.
In the embodiment of the invention, the cathode is a three-dimensional nitrogen-doped carbon loaded foamy copper electrode, the three-dimensional nitrogen-doped carbon has a porous structure, a high specific surface area and excellent electron transfer capacity, and the three-dimensional structure and the internally connected nitrogen-doped carbon network can provide a multi-dimensional electron transfer path and rapidly transfer cathode electrons to nitrate pollutants on the surface. In addition, the nitrogen atom doping can introduce defect sites into carbon crystal lattices, change the Fermi level and increase catalytic active sites, so that the electrochemical activity can be further improved by the nitrogen atom doping, and the electro-catalytic reduction performance of the cathode on nitrate is improved.
The three-dimensional nitrogen-doped carbon-supported foamy copper electrode of the cathode plate can be prepared in a quartz tube furnace by a chemical vapor deposition method. Specifically, first, a copper foam substrate (pore density 100ppi, thickness 1.5mm) was ultrasonically cleaned in an acetic acid solution, ethanol and acetone, respectively, to remove oxygen from the surface of the copper foamCompounds and organic materials. It was then placed in a quartz tube and 260sccm Ar and 35sccm H were passed through at 300mTorr2The mixed gas of (3) was heated to 960 ℃ at 10 ℃/min. And after annealing for 15min, introducing pyridine vapor through evaporation to perform nitrogen-doped carbon deposition, wherein the deposition time is 3 min. Thereafter, the pyridine vapor was cut off. And naturally cooling the tubular furnace to room temperature to obtain the three-dimensional nitrogen-doped carbon-loaded foam copper electrode. Referring to fig. 2, fig. 2(a) is a transmission electron microscope image (inset is selected area electron diffraction pattern) of nitrogen-doped carbon, and fig. 2(b) is a scanning electron microscope image of three-dimensional nitrogen-doped carbon-supported copper foam electrode and a copper, carbon and nitrogen energy spectrum distribution image.
Further, the cathode plate and the anode plate are identical in shape. The shapes of the cathode plate and the anode plate in the embodiment of the invention can be properly designed according to the size of the reactor, thereby realizing the high-efficiency removal of the electroplating wastewater to be treated in the reactor.
Preferably, the cathode plate and the anode plate are arranged parallel to each other. So that the electric field distribution and the solid-liquid contact are relatively uniform, and the chemical reaction of the cathode and the anode is relatively stable, thereby realizing the high-efficiency removal of the total nitrogen in the electroplating wastewater.
Specifically, the cathode plates and the anode plates may be uniformly arranged to cross each other according to the number of the cathode plates and the anode plates. For example, when 4 cathode plates and 2 anode plates are provided, the cathode plates, the anode plates, the cathode plates, the anode plates and the cathode plates can be arranged in sequence.
Further, the number ratio of the cathode plates to the anode plates is 1:4-4: 1. The method can be specifically determined according to the concentration ratio of nitrate nitrogen to ammonia nitrogen in the electroplating wastewater, the oxidation reaction rate of a single anode plate and the reduction reaction rate of a single cathode plate. Preferably, the number ratio of the cathode plates to the anode plates is 1:1 to 4: 1.
Specifically, the chemical reactions that take place in the cathode and anode plates are as follows:
a negative plate: the nitrate nitrogen is reduced by the combined action of direct electrical reduction of electrons transferred on the surface of a cathode and indirect electrical reduction of atomic hydrogen generated by water electrolysis, and the specific reaction formula is as follows:
NO3 -+H2O+2e-→NO2 -+2OH- (1)
NO2 -+6H2O+6e-→NH4 ++8OH- (2)
2NO2 -+4H2O+6e-→N2+8OH- (3)
2H2O+2e-→2H*+2OH- (4)
NO3 -+H*→NO2 -+NH4 ++N2+H2O (5)
NO2 -+H*→NH4 ++N2+H2O (6)
an anode plate: electrooxidation and electrolysis of Cl by titanium-ruthenium mesh electrode-Generated active chlorine (HClO/ClO)-) Oxidizing ammonia nitrogen and organic nitrogen, wherein the specific reaction formula is as follows:
NH4 ++H2O→N2+e-+H+ (7)
2Cl-→Cl2+2e- (8)
Cl2+H2O→HClO+H++Cl- (9)
HClO→H++ClO- (10)
2NH4 ++3HClO→3H2O+5H++3Cl-+N2 (11)
2NH4 ++3ClO-→3H2O+2H++3Cl-+N2 (12)
NH4 ++3ClO-→H2O+2H++4Cl-+NO3 - (13)
NO2 -+HClO→NO3 -+H++Cl- (14)
it is to be noted that, because chloride ions are introduced into the electroplating wastewater during the acid cleaning process, the concentration can reach 2-8g/L, so Cl used in the reaction-All are original in the wastewater, noneAdditional additions are required.
The invention also provides a treatment method for removing the total nitrogen in the electroplating wastewater by using the electrochemical reaction device, which comprises the following steps: introducing the electroplating wastewater into a reactor, and applying current by an external direct current power supply.
According to the method for treating the electroplating wastewater by using the electrochemical reaction device, provided by the embodiment of the invention, nitrate nitrogen is reduced by direct electron reduction and indirect active atom hydrogen reduction at the cathode, and ammonia nitrogen and organic nitrogen are oxidized by electrooxidation and electroproduction of active chlorine (HClO/ClO-).
Furthermore, PDS can be added into the system to strengthen the complex breaking of organic amine. Specifically, Persulfate (PDS) is added to the reactor so that the molar ratio of the organic nitrogen to the PDS is 1: 1-1: 10.
In the embodiment of the invention, three-dimensional nitrogen-doped carbon-loaded foamy copper is used as a cathode, and after PDS is added into a reaction system, cathode electrons and Cu can activate PDS to generate SO4 ·-Changing Cu to Cu2O, and Cu2O can be further reduced to Cu at the cathode0Thereby realizing the circulation process of Cu (0) -Cu (I) -Cu (II) -Cu (0) on the surface of the cathode and promoting the decomposition of PDS to generate active free radicals.
The reaction formula is as follows:
Cu(s)-e-→Cu+(s)
S2O8 2-+e-→SO4 ·－+SO4 2-
Cu2O+2H+→Cu2+(aq)+Cu(s)+H2O
Cu2+(aq)+2e-→Cu(s)
SO produced thereby4 ·-Can strengthen the complex breaking capability of heavy metal-organic amine complex (such as Ni-EDTA), effectively decompose organic nitrogen, and decompose and convert the organic nitrogen into nitrate nitrogen or ammonia nitrogen, thereby further being removed by electric reduction/oxidation.
Further, the density of the applied current is 1-20mA/cm2(ii) a Preferably, the density of the applied current is 3-10mA/cm2。
Further, the hydraulic retention time is 2-6 hours.
Furthermore, the concentration of nitrate nitrogen in the electroplating wastewater can be 0-500 mg/L; the concentration of ammonia nitrogen can be 0-1000 mg/L; the concentration of organic nitrogen may be 0-500 mg/L.
Furthermore, the concentration of total nitrogen in the electroplating wastewater is 0-2000 mg/L. However, the electrochemical treatment method provided by the invention is not limited by concentration, and electroplating wastewater with higher total nitrogen concentration can be efficiently treated.
The specific implementation process of the embodiment of the invention is as follows: the waste water enters a reactor, the cathode can reduce nitrate nitrogen into ammonia nitrogen and nitrogen under the action of a constant current electric field, the anode can efficiently convert the ammonia nitrogen in the waste water and the ammonia nitrogen generated by the reduction of the nitrate nitrogen into the nitrogen through electrochemical oxidation and indirect oxidation of electrogenerated active chlorine, and meanwhile, organic nitrogen can be further decomposed into the ammonia nitrogen or the nitrate nitrogen and then converted into the nitrogen. The high-efficiency removal of nitrate nitrogen, ammonia nitrogen and organic nitrogen is synchronously realized through the electrochemical reduction/oxidation reaction process. The reaction can be carried out in the same reactor without adding a reducing agent and an oxidizing agent.
The present invention will be described in detail with reference to examples.
Example 1
The cathode is connected with the negative electrode of a power supply by using three-dimensional nitrogen-doped carbon-loaded foamy copper, the anode is connected with the positive electrode of the power supply by using a titanium-ruthenium net, and the negative plate and the positive plate are arranged at intervals (see the attached figure 1) in a proportion of the cathode: the anode is 2:1 (4 cathode plates and 2 anode plates), and the distance between the plates is 5 mm. The power supply is turned on, and the hydraulic retention time is 3 hours.
Water quality of inlet water: initial pH 6.78, conductivity 13.88ms/cm, Dissolved Oxygen (DO) 12.26mg/L, COD 214mg/L, nitrate nitrogen 80mg/L, ammonia nitrogen 160mg/L, total nitrogen 300mg/L, current density 5mA/cm2。
After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 7.5mg/L, the ammonia nitrogen is 0mg/L, the total nitrogen is 14mg/L, and the total nitrogen removal rate is 95.33%.
Example 2
The cathode is connected with the negative electrode of a power supply by using three-dimensional nitrogen-doped carbon-loaded foamy copper, the anode is connected with the positive electrode of the power supply by using a titanium-ruthenium net, and the negative plate and the positive plate are arranged at intervals (see the attached figure 1) in a proportion of the cathode: the anode is 2:1 (4 cathode plates and 2 anode plates), and the distance between the plates is 5 mm. The power supply is turned on, and the hydraulic retention time is 3 hours.
Water quality of inlet water: initial pH 6.78, conductivity 13.88ms/cm, Dissolved Oxygen (DO) 12.26mg/L, COD 214mg/L, nitrate nitrogen 80mg/L, ammonia nitrogen 160mg/L, total nitrogen 300mg/L, current density 10mA/cm2。
After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 4.5mg/L, the ammonia nitrogen is 0mg/L, the total nitrogen is 6.0mg/L, and the total nitrogen removal rate is 98%.
Example 3
The cathode is connected with a power cathode by using three-dimensional nitrogen-doped carbon loaded foamy copper, the anode is connected with a power anode by using a titanium-ruthenium net, the cathode plate and the anode plate are placed at intervals, and the proportion of the cathode and the anode is adjusted to be the cathode according to the lower proportion of the nitrate nitrogen in the inlet water: the anode is 1:1 (2 cathode plates and 2 anode plates), and the distance between the plates is 5 mm. The power supply is turned on, and the hydraulic retention time is 3 hours.
Water quality of inlet water: initial pH 6.78, conductivity 13.88ms/cm, Dissolved Oxygen (DO) 12.26mg/L, COD 214mg/L, nitrate nitrogen 35mg/L, ammonia nitrogen 200mg/L, total nitrogen 300 mg/L; the current density was set to 5mA/cm2。
After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 2.5mg/L, the ammonia nitrogen is 0mg/L, the total nitrogen is 5.5mg/L, and the total nitrogen removal rate is 98.17%.
Example 4
The cathode is connected with a power cathode by using three-dimensional nitrogen-doped carbon loaded foamy copper, the anode is connected with a power anode by using a titanium-ruthenium net, the cathode plate and the anode plate are placed at intervals, and the proportion of the cathode and the anode is adjusted to be the cathode according to the higher proportion of the nitrate nitrogen in the inlet water: the anode is 3:1 (6 cathode plates and 2 anode plates), and the distance between the plates is 5 mm. The power supply is turned on, and the hydraulic retention time is 3 hours
Water quality of inlet water: initial pH 6.78, electricityConductivity 13.88ms/cm, Dissolved Oxygen (DO) 12.26mg/L, COD 214mg/L, nitrate nitrogen 120mg/L, ammonia nitrogen 120mg/L, total nitrogen 300mg/L, current density 5mA/cm2。
After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 1.5mg/L, the ammonia nitrogen is 0mg/L, the total nitrogen is 2.53mg/L, and the total nitrogen removal rate is 99.16%.
Example 5
The cathode is connected with the negative electrode of the power supply by using three-dimensional nitrogen-doped carbon-loaded foamy copper, the anode is connected with the positive electrode of the power supply by using a titanium-ruthenium net, and the negative plate and the positive plate are arranged at intervals and are in proportion as the cathode: the anode is 2:1 (4 cathode plates and 2 anode plates), and the distance between the plates is 5 mm. The power supply is turned on, and the hydraulic retention time is 4 hours.
Water quality of inlet water: initial pH 6.78, conductivity 13.88ms/cm, Dissolved Oxygen (DO) 12.26mg/L, COD 214mg/L, nitrate nitrogen 80mg/L, ammonia nitrogen 160mg/L, total nitrogen 300mg/L, current density 5mA/cm2。
After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 2.6mg/L, the ammonia nitrogen is 0mg/L, the total nitrogen is 4.5mg/L, and the total nitrogen removal rate is 98.50%.
Example 6
The difference from example 1 is that 2.0g/L of PDS was fed into the reactor.
After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 6.7mg/L, the ammonia nitrogen is 0mg/L, the total nitrogen is 7.3mg/L, and the total nitrogen removal rate is 97.57%.
Comparative example 1
The negative plate was a three-dimensional nitrogen-doped carbon-supported copper foam electrode replaced with a stainless steel plate under the same conditions as in example 1.
After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 102mg/L, the ammonia nitrogen is 3.4mg/L, the total nitrogen is 162mg/L, and the total nitrogen removal rate is 46.0%.
Comparative example 2
The anode plate was a titanium-based lead dioxide electrode instead of a titanium-ruthenium mesh electrode, and the other conditions were the same as in example 1.
After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 17mg/L, the ammonia nitrogen is 43mg/L, the total nitrogen is 115mg/L, and the total nitrogen removal rate is 61.67%.
The comparative examples 1 and 2 show that the total nitrogen removal rate is obviously reduced when the cathode plate and the anode plate are changed, and only when the anode plate is a titanium ruthenium mesh electrode and the cathode plate is a three-dimensional nitrogen-doped carbon-loaded foamy copper electrode, the electrode group can play a synergistic effect in the reactor, so that the total nitrogen removal rate is greatly improved.
Comparative example 3
Cathode: the anode was 1:1 (1 cathode and anode plate, respectively), and the other conditions were the same as in example 1. After the treatment of the electrochemical synchronous denitrification reactor, the nitrate nitrogen is 47mg/L, the ammonia nitrogen is 26mg/L, the total nitrogen is 108mg/L, and the total nitrogen removal rate is 64.0 percent. Further, in order to obtain substantially the same removal effect as in example 1, the required hydraulic retention time was 10 hours or more.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (5)

1. A method for removing total nitrogen in electroplating wastewater by using an electrochemical reaction device is characterized by comprising the following steps:
introducing electroplating wastewater into a reactor, applying current through an external direct-current power supply, and adding persulfate into the reactor to enable the molar ratio of organic nitrogen to persulfate to be 1: 1-1: 10;
wherein the electrochemical reaction apparatus comprises a reactor;
at least one cathode plate disposed within the reactor;
at least one anode plate disposed within the reactor;
the negative plate and the positive plate are connected with an external direct current power supply;
correspondingly adjusting the number of the anode plates and the cathode plates according to the concentration of ammonia nitrogen and organic nitrogen in the electroplating wastewater to be treated, the anodic oxidation reaction rate, the concentration of nitrate nitrogen and the cathodic reduction reaction rate; the number ratio of the cathode plates to the anode plates is 1:1-4:1, wherein the number ratio of the cathode plates to the anode plates is not 1: 1; the anode plate is a titanium ruthenium net electrode, and the cathode plate is a three-dimensional nitrogen-doped carbon-loaded foam copper electrode.
2. The method of claim 1,
the cathode plate and the anode plate have the same shape.
3. The method of claim 1,
the negative plate and the positive plate are arranged in parallel.
4. The method of claim 1,
the density of the applied current is 1-20mA/cm2。
5. The method of claim 4,
the density of the applied current is 3-10mA/cm2。
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