阅读说明：本技术 一种硝酸盐污水的处理方法 (Nitrate sewage treatment method ) 是由 黄乙辉 唐念 张路路 彭进平 于 2021-07-02 设计创作，主要内容包括：本发明涉及污水处理技术领域,尤其涉及一种硝酸盐污水的处理方法,包括以下步骤,S1、采用电化学装置；S2、在所述电解槽的外周壁安装两块永磁板,使所述两块永磁板相对设置以及使得所述两块永磁板的板面均与所述阳极板的板面和阴极板的板面垂直；S3、将硝酸盐污水注入阳极室和将待处理的硝酸盐污水注入阴极室,使阴极室内的污水浓度大于阳极室的污水浓度；S4、在所述阳极板和所述阴极板上施加直流电场,对阴极室内的硝酸盐污水进行还原处理,该硝酸盐污水的处理方法具有原率高和还原速度快的优点。(The invention relates to the technical field of sewage treatment, in particular to a nitrate sewage treatment method, which comprises the following steps of S1, adopting an electrochemical device; s2, installing two permanent magnet plates on the outer peripheral wall of the electrolytic cell, enabling the two permanent magnet plates to be oppositely arranged and enabling the plate surfaces of the two permanent magnet plates to be perpendicular to the plate surfaces of the anode plate and the cathode plate; s3, injecting nitrate sewage into the anode chamber and injecting nitrate sewage to be treated into the cathode chamber, so that the sewage concentration in the cathode chamber is higher than that in the anode chamber; s4, applying a direct current electric field on the anode plate and the cathode plate to carry out reduction treatment on the nitrate sewage in the cathode chamber, wherein the treatment method of the nitrate sewage has the advantages of high original rate and high reduction speed.)

1. A method for treating nitrate sewage is characterized in that: comprises the following steps of (a) carrying out,

s1, adopting an electrochemical device, wherein the electrochemical device comprises a direct current power supply, an electrolytic cell and a proton exchange membrane which is arranged in the electrolytic cell and divides the electrolytic cell into a cathode chamber and an anode chamber, the cathode chamber is provided with a cathode plate, the anode chamber is provided with an anode plate, the positive pole of the direct current power supply is connected with the anode plate, and the negative pole of the direct current power supply is connected with the cathode plate;

s2, installing two permanent magnet plates on the outer peripheral wall of the electrolytic cell, enabling the two permanent magnet plates to be oppositely arranged and enabling the plate surfaces of the two permanent magnet plates to be perpendicular to the plate surfaces of the anode plate and the cathode plate, and applying a magnetic field in the direction perpendicular to the direct current electric field;

s3, injecting nitrate sewage into the anode chamber and injecting nitrate sewage to be treated into the cathode chamber, so that the sewage concentration in the cathode chamber is higher than that in the anode chamber;

and S4, applying a direct current electric field on the anode plate and the cathode plate to reduce the nitrate sewage in the cathode chamber.

2. The nitrate-containing sewage treatment method according to claim 1, wherein: the bottom in cathode chamber is equipped with the cathode chamber water inlet, the top in cathode chamber is equipped with the cathode chamber delivery port, the cathode chamber water inlet is close to proton exchange membrane just keeps away from the negative plate, the cathode chamber delivery port is close to the negative plate and keeps away from proton exchange membrane, the cathode chamber water inlet with the cathode chamber delivery port is connected with the micro peristaltic pump respectively.

3. The nitrate-containing sewage treatment method according to claim 1, wherein: the cathode chamber is provided with a loop channel, two ports of the loop channel are a water outlet and a water inlet respectively, the water inlet and/or the water outlet is connected with a micro peristaltic pump, the cathode chamber is also provided with a water inlet and a water outlet, and the water inlet and the water outlet are respectively provided with an electromagnetic valve.

4. The nitrate-containing sewage treatment method according to claim 1, wherein: the anode chamber is provided with an anode chamber water inlet and an anode chamber water outlet, and the anode chamber water inlet and the anode chamber water outlet are respectively connected with a micro peristaltic pump.

5. The nitrate-containing sewage treatment method according to claim 1, wherein: still be equipped with a plurality of netted electrode boards in the negative pole room, a plurality of netted electrode boards set up side by side just the face of a plurality of netted electrode boards aligns each other, leaves the interval between the adjacent netted electrode board.

6. The nitrate-containing sewage treatment method according to claim 5, wherein: the interval between the reticular electrode plates is 5 mm.

7. The nitrate-containing sewage treatment method according to claim 5, wherein: the cathode plate is a Cu-Sn-Bi cathode plate, the anode plate is a pure Ti anode plate, and the electrode plate is a Cu-Sn-Bi electrode plate.

8. The nitrate-containing sewage treatment method according to claim 1, wherein: and an aeration device is arranged at the bottom of the cathode chamber.

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a method for treating nitrate sewage.

Background

Nitrogen is very important for all life but is harmful to life if its form or location is not correct. In water, nitrogen is usually present in the form of nitrate, nitrite, ammonium ion, nitrate is a non-ligand formed oxyanion, has high mobility, and is soluble in water. With the rapid development of industry and agriculture, people overuse nitrogen fertilizers and lack of proper treatment on domestic sewage and industrial sewage, nitrate pollution in water becomes a problem which cannot be ignored. If excessive nitric acid is added to the drinking water, methemoglobinemia is caused by nitrite in the human gastrointestinal tract. Nitrite is reduced from nitrate by gastrointestinal microorganisms, oxidizing the ferrous ions in hemoglobin to ferric ions, thereby disabling the oxygen transport mechanism of the red blood cells. Oxygen transport disorders can lead to purple color, fatigue, shortness of breath, hypoxia of the brain, and even death. Infants and fetuses are particularly susceptible to methemoglobinemia, also known as "bluebaby syndrome". The world health organization sets the maximum pollutant level (MCL) of nitrate in drinking water to be 50mg/L, and the maximum limit of nitrate nitrogen in the sanitary Standard for Drinking Water of China is 10 mg/L.

Common methods for removing nitrates from water include ion exchange, reverse osmosis, electrodialysis, active metal reduction, catalytic reduction, biological and electrochemical methods. Among them, the electrochemical method has the advantages of stable effect, simple process, small equipment floor area, stable effect, environmental protection and the like, so the electrochemical method is widely applied to sewage treatment. However, the electrochemical method still has the defects in reducing anions such as nitrate radical and the like: electrochemical methods have low current utilization, high byproduct yield, and long reaction time, for example, the speed control step of nitrate radical reduction is NO₃ ^-Adsorption on the electrode and transfer of electrons to the cathode material plus protons (H) in the aqueous solution⁺) Reaction to form NO₂ ^-But NO₃ ^-Is negatively charged, the cathode repels NO due to the action of electric field force₃ ^-The anode will attract NO due to the action of the electric field force₃ ^-This then leads to NO₃ ^-By reduction of (2) to (3)₂ ^-Is re-oxidized to NO around the anode₃ ^-So that the total duration of reduction is extended and the reduction efficiency is reduced.

Disclosure of Invention

The invention aims to overcome the problems of the prior art and provide a nitrate sewage treatment method with high reduction rate and high reduction speed.

In order to achieve the purpose, the invention adopts the following scheme:

provides a method for treating nitrate sewage, which comprises the following steps,

s1, adopting an electrochemical device, wherein the electrochemical device comprises a direct current power supply, an electrolytic cell and a proton exchange membrane which is arranged in the electrolytic cell and divides the electrolytic cell into a cathode chamber and an anode chamber, the cathode chamber is provided with a cathode plate, the anode chamber is provided with an anode plate, the positive pole of the direct current power supply is connected with the anode plate, and the negative pole of the direct current power supply is connected with the cathode plate;

s2, installing two permanent magnet plates on the outer peripheral wall of the electrolytic cell, enabling the two permanent magnet plates to be oppositely arranged and enabling the plate surfaces of the two permanent magnet plates to be perpendicular to the plate surfaces of the anode plate and the cathode plate, and applying a magnetic field in the direction perpendicular to the direct current electric field;

s3, injecting nitrate sewage into the anode chamber and injecting nitrate sewage to be treated into the cathode chamber, so that the sewage concentration in the cathode chamber is higher than that in the anode chamber;

and S4, applying a direct current electric field on the anode plate and the cathode plate to reduce the nitrate sewage in the cathode chamber.

Further, the bottom in cathode chamber is equipped with the cathode chamber water inlet, the top in cathode chamber is equipped with the cathode chamber delivery port, the cathode chamber water inlet is close to proton exchange membrane just keeps away from the negative plate, the cathode chamber delivery port is close to the negative plate and keeps away from proton exchange membrane, the cathode chamber water inlet with the cathode chamber delivery port is connected with the micro peristaltic pump respectively.

Furthermore, the cathode chamber is provided with a loop channel, two ports of the loop channel are respectively a water outlet and a water inlet, the water inlet and/or the water outlet is connected with a micro peristaltic pump, the cathode chamber is also provided with a water inlet and a water outlet, and the water inlet and the water outlet are respectively provided with an electromagnetic valve.

Furthermore, the anode chamber is provided with an anode chamber water inlet and an anode chamber water outlet, and the anode chamber water inlet and the anode chamber water outlet are respectively connected with a micro peristaltic pump.

Further, still be equipped with a plurality of netted electrode boards in the negative pole room, a plurality of netted electrode boards set up side by side just the face of a plurality of netted electrode boards aligns each other, leaves the interval between the adjacent netted electrode board.

Further, the interval between the net-shaped electrode plates is 5 mm.

Further, the cathode plate is a Cu-Sn-Bi cathode plate, the anode plate is a pure Ti anode plate, and the electrode plate is a Cu-Sn-Bi electrode plate.

Further, an aeration device is arranged at the bottom of the cathode chamber.

Compared with the prior art, the invention has the following advantages:

(1) the permanent magnetic plate is arranged on the outer wall of the electrolytic cell which generates electrochemical reaction, the permanent magnetic plate generates a magnetic field applied in the vertical direction of the electric field, and Lorentz force generated by the magnetic field force overcomes the electrostatic repulsion of the cathode to nitrate, so that the possibility of the nitrate contacting with the surface of the cathode is increased, the reduction efficiency of the cathode to the nitrate is effectively improved, and byproducts are greatly reduced.

(2) The invention divides the electrolytic cell into the cathode chamber and the anode chamber by the proton exchange membrane, effectively prevents the intermediate reduction product on the cathode side from migrating to the periphery of the anode and being oxidized again, and improves the current efficiency.

(3) According to the invention, nitrate sewage with higher concentration than that of the anode chamber is filled in the cathode chamber, so that the anion in the cathode chamber is reduced to migrate to the anode chamber by utilizing the reverse osmosis effect, and the reduction efficiency is improved.

Drawings

The present application will be described in further detail with reference to the following drawings and detailed description.

FIG. 1 is a schematic view of the structure of a nitrate-containing wastewater treatment method of the present invention.

FIG. 2 is a side view of a nitrate containing wastewater treatment method of the present invention.

Fig. 3 is a schematic diagram of the lorentz force generated by the permanent magnet plate of the present invention.

The figure includes:

a direct current power supply 1; an electrolytic cell 2; a cathode chamber 3; an anode chamber 4; a proton exchange membrane 5; a cathode plate 6; an anode plate 7; a permanent magnet plate 8; a water inlet 9 of the cathode chamber; a water outlet 10 of the cathode chamber; a micro peristaltic pump 11; a water inlet 12 of the anode chamber; a water outlet 13 of the anode chamber; a mesh-shaped electrode plate 14; an aeration device 15; the magnetic field direction 16.

Detailed Description

The present application is further described in conjunction with the following examples.

Example 1

To facilitate the explanation of the principle of application of the nitrate-containing wastewater treatment method of the present invention, nitrate NO was used in this example₃ ^-The method for treating nitrate containing sewage of the present invention can also treat sewage containing other ions in practical applications.

The embodiment discloses a method for treating nitrate sewage, which comprises the following steps,

s1, adopting the electrochemical device shown in fig. 1-3, the electrochemical device comprises a dc power supply 1, an electrolytic cell 2 and a proton exchange membrane 5 arranged in the electrolytic cell 2 and dividing the electrolytic cell 2 into a cathode chamber 3 and an anode chamber 4, the cathode chamber 3 is provided with a cathode plate 6, the anode chamber 4 is provided with an anode plate 7, the anode of the dc power supply 1 is connected with the anode plate 7, and the cathode of the dc power supply 1 is connected with the cathode plate 6;

s2, installing two permanent magnet plates 8 on the outer peripheral wall of the electrolytic cell 2, enabling the two permanent magnet plates 8 to be oppositely arranged and enabling the plate surfaces of the two permanent magnet plates 8 to be perpendicular to the plate surfaces of the anode plate 7 and the cathode plate 6, and applying a magnetic field in the direction perpendicular to the direct current electric field;

s3, injecting nitrate sewage into the anode chamber 4 and injecting nitrate sewage to be treated into the cathode chamber 3, so that the sewage concentration in the cathode chamber 3 is higher than that in the anode chamber 4;

and S4, applying a direct current electric field on the anode plate 4 and the cathode plate 3 to reduce the nitrate sewage in the cathode chamber 3.

In use, protons (H) in the anode compartment 4⁺) Passes through the proton exchange membrane 5 to reduce NO in the wastewater in the raw cathode chamber 3₃ ^-The magnetic field direction 16 generated by the magnetic field and the Lorentz force generated by the magnetic field overcome the electrostatic repulsion of the negative electrode to the negative ions, thereby increasing the possibility of the negative ions contacting with the surface of the negative electrode, effectively improving the reduction efficiency of the negative electrode to the negative ions and greatly reducing byproducts.

The electrochemical reduction of nitrate was as follows: the first step is NO in the aqueous phase₃ ^-Electrons adsorbed on the surface of the electrode and then transferred to the cathode plate and protons (H) in the aqueous solution⁺) Reaction to form NO₂ ^-This is the rate determining step of the overall reaction process, the NO produced₂ ^-Direct generation of NO by charge transfer₂ ^2-，NO₂ ^2-Rapid hydrolysis (k ═ 1.0X 10)⁵s^-1) And produces adsorbed NO. NO adsorbed on the surface of the electrode generates N by charge transfer₂O，N₂O is generated into N through electrochemical reduction reaction₂And (3) separating out, wherein the reaction equation is as follows:

NO₃ ^-+2H⁺+2e-→NO₂ ^-+H₂O

NO₂ ^-(ad)+e^-→NO₂ ^2-(ad)

NO₂ ^2-(ad)+H₂O→NO(ad)+2OH^-

NO(ad)+NO(aq)+H⁺+e^-→HN₂O₂

HN₂O₂(ad)+H⁺+e^-→N₂O(ad)+H₂O

N₂O+2H⁺+2e^-→N₂+H₂O

according to the mechanism of electrochemical reduction of nitrate radical, canTo know NO₃ ^-Need to be adsorbed on the surface of the electrode e^-Directly or by protons (H) in water⁺) Indirectly reduced, but NO₃ ^-Is negatively charged and will be repelled by the cathode due to the action of the electric field force, thereby reducing NO₃Adsorption ratio of-and thus decrease of NO₃ ^-The reduction efficiency of the invention is that the magnetic field is applied in the vertical direction of the electric field, and the Lorentz force and the viscous force of the water flow are utilized to overcome the NO of the cathode₃ ^-Thereby increasing NO₃ ^-And H adsorbed on the cathode plate⁺And e released from the cathode^-Possibility of contact, increase of NO₃ ^-The degradation rate of (c).

In this embodiment, the bottom in cathode chamber 3 is equipped with cathode chamber water inlet 9, the top in cathode chamber 3 is equipped with cathode chamber delivery port 10, cathode chamber water inlet 9 is close to proton exchange membrane 5 just keeps away from cathode plate 6, cathode chamber delivery port 10 is close to cathode plate 6 and keeps away from proton exchange membrane 5, cathode chamber water inlet 9 with cathode chamber delivery port 10 is connected with micro peristaltic pump 11 respectively. The ingenious position design of the cathode chamber water inlet 9 and the cathode chamber water outlet 10 enables sewage water flow to be treated to generate viscous force, the viscous force deviates to the cathode plate 6, and NO is enabled to be generated₃ ^-Can be biased towards the cathode plate, thereby further overcoming the defect of NO in the cathode pair₃ ^-Is electrostatically repelled, and then NO is increased₃ ^-The possibility of contact with the cathode surface further improves the reduction efficiency. Whereas the micro peristaltic pump 11 increases the flow driving force.

In this embodiment, the anode chamber 4 is provided with an anode chamber water inlet 12 and an anode chamber water outlet 13, the anode chamber water inlet 12 and the anode chamber water outlet 13 are respectively connected with a micro peristaltic pump 11, and the anode chamber water inlet 12 and the anode chamber water outlet 13 enable the anode chamber 4 to generate water flow force, thereby reducing the attraction force of the anode chamber 4.

In this embodiment, a plurality of mesh electrode plates 14 are further disposed in the cathode chamber 3, the mesh electrode plates 14 are disposed side by side, and the surfaces of the mesh electrode plates 14 face each otherAnd a space is left between the adjacent mesh electrode plates 14. When the mesh electrode plate 14 is added into the electrolytic tank 2 and electrified, free electrons are generated on the surface and can be used for nitrate radical reduction reaction, and NO is added into the mesh electrode plate 14₃ ^-While not affecting the flow of the sewage.

In this embodiment, the interval between the mesh electrode plates 14 is 5 mm.

In this embodiment, the cathode plate 6 is a Cu-Sn-Bi cathode plate 6, the anode plate 7 is a pure Ti anode plate 7, and the electrode plate is a Cu-Sn-Bi electrode plate.

In this embodiment, an aeration device 15 is provided at the bottom of the cathode chamber 3, and when nitrate radicals in the sewage are reduced, nontoxic N is supplied through the aeration device 15₂And is discharged to the atmosphere.

Example 2

This embodiment differs from embodiment 1 in that the cathode chamber is provided with a loop channel (not shown) having a water outlet and a water inlet at its two ends, and a micro peristaltic pump is connected to the water inlet and/or the water outlet, and the loop channel allows the sewage to be circulated for treatment to improve the treatment effect. The cathode chamber is also provided with a water inlet and a water outlet, the water inlet and the water outlet are respectively provided with an electromagnetic valve, and when sewage needs to be discharged or input, the electromagnetic valve is controlled.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the protection scope of the present application, and although the present application is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present application without departing from the spirit and scope of the technical solutions of the present application.