CN112279345A

CN112279345A - Method for solving electrochemical cathode scaling

Info

Publication number: CN112279345A
Application number: CN202011152134.7A
Authority: CN
Inventors: 冯岩; 卢玉玉; 吴心玥; 周海琳; 任昊成; 于海峰
Original assignee: University of Jinan
Current assignee: University of Jinan
Priority date: 2020-10-26
Filing date: 2020-10-26
Publication date: 2021-01-29

Abstract

The invention provides a method for solving cathode scaling, which aims to solve the phenomenon of cathode scaling in an electrocatalysis process and a series of subsequent problems such as reactor blockage, low current efficiency or hardened particle electrodes and the like, and also increases gas distribution hysteresis and non-uniform gas distribution in a backwashing process, so that a series of operation management problems such as hardened filter materials, high operation pressure, unsmooth water and the like caused by insufficient local backwashing strength are solved. In view of the above problems, a method for solving the scaling problem of the cathode is provided. A large number of experimental phenomena prove that after a reactor which is used for a long time uses the back washing method provided by the invention, the scale on the surface of the cathode is obviously reduced, and after the newly-built reactor uses the back washing method provided by the invention, the scale on the cathode is not obviously deposited.

Description

Method for solving electrochemical cathode scaling

Technical Field

The invention discloses a method for solving the scaling phenomenon of an electrochemical cathode. Can be used for advanced treatment units of sewage and wastewater plants.

Background

The electrochemical process is to generate a large amount of free radicals through chemical reaction, electrochemical process or physical process in an electrochemical reactor under the action of an external electric field, and degrade pollutants in the sewage and the wastewater by utilizing the strong oxidation characteristic of the free radicals. The contaminants are reduced or removed by direct electrochemical reaction or indirect electrochemical conversion at the electrodes. The electrochemical water treatment technology is widely applied to treating wastewater generated in the industries of chemical engineering, dye, biological pharmacy and the like. Due to the complexity of organic wastewater, it is impossible to completely remove the refractory materials in water by a single method, and many researchers have begun to explore new possibilities by coupling various methods with electrochemical reactions, such as three-dimensional electrochemical reactors, electrochemical bioreactors, electro-fenton reactions, ozone-electrochemical coupling reactors, electromagnetic coupling reactors, and the like.

The electrochemistry has many advantages in sewage treatment, the method generally does not need to add chemical agents, can better avoid secondary pollution, and has the advantages of small floor area, simple and convenient operation and small sludge amount. However, one of the main reasons that has not been widely used is that the cathode fouling phenomenon in the electrochemical reaction process is severe, which easily causes many problems such as: (1) in the back flushing process of the electrochemical biological filter longitudinally arranged as shown in the attached figure 1, scaling on a cathode plate often causes uneven water distribution and gas distribution, the back flushing strength of a local area is overlarge, the water distribution often has hysteresis, the local area close to an air inlet end firstly distributes water and gas or even the strength is far beyond the designed strength, and the water distribution and gas distribution of other areas has obvious hysteresis and extremely uneven strength; (2) in the three-dimensional electro-fenton reactor shown in fig. 2, the reactor is blocked, the current efficiency is low and the particle electrodes are hardened due to scaling on the cathode plate; (3) in the back flushing process of the annular enlarged anode electrochemical biological filter shown in the attached figure 3, excessive deposition is caused to be generated below the reactor due to scaling on the central cathode column, so that the problems of reactor blockage, low current efficiency, hardening of particle electrodes, mixed bed of a supporting layer and a filter material layer and the like are caused. Various phenomena make daily production and operation work tired. At present, a method for solving the scaling of the cathode is urgently needed to thoroughly solve the problem of the current situation.

Disclosure of Invention

The invention provides a method for solving cathode scaling, which aims to solve a series of problems caused by cathode scaling, such as reactor blockage, low current efficiency or hardened particle electrodes, and also solves a series of operation management problems of hardened filter materials, high operation pressure, unsmooth water passing and the like caused by insufficient local backwashing strength due to gas distribution hysteresis and uneven gas distribution in the backwashing process. The invention discloses a method for solving the problem of cathode scaling of an electrochemical biological aerated filter.

The invention provides a method for carrying out backwashing on sewage and wastewater treatment processes involving an electrochemical process at regular time, wherein the cathode and the anode are exchanged during the backwashing, the cathode plate is changed into the anode during the backwashing, oxygen is generated on the surface, the anode and the cathode plate are synthesized into a shearing force which is enough to drop off scaling substances with an upward flushing force in the backwashing process, and the dropping substances flow out along with backwashing water, so that the gas washing time is increased after the cathode and the anode are exchanged, and experimental data prove that the gas washing time is 5-8 min and the gas-water combined flushing time is 7-10 min.

A large number of examples prove that the method provided by the invention can effectively solve the problem of cathode scaling in the process of treating sewage and wastewater by using an electrochemical process.

The invention is characterized in that:

1. performing timed back flushing on a device for treating sewage and wastewater by an electrochemical process, and exchanging a cathode and an anode during the back flushing; carrying out air washing on the reactor for 5-8 minutes; flushing for 7-10 minutes by using gas-water combination; and (5) washing for 8-10 minutes, and finally exchanging the cathode and the anode again.

2. Each reactor is provided with a commutator for exchanging electrodes at its power supply for controlling the exchange process of the electrodes in the reactor.

3. The voltage intensity in the reaction system during back flushing is 30-100V.

4. The air washing time is 5-8 minutes during back washing, wherein the air washing strength is 12L-16L/m²•s。

5. The gas-water combined flushing time is 7-10 minutes during back flushing, wherein the air flushing intensity is 12L-16L/m²S; the water washing intensity is 4L-6L/m²•s。

6. The washing time is 8-10 minutes during back washing, wherein the washing intensity is 4L-6L/m²•s。

7. The back flushing interval is 5-12 days.

Drawings

FIG. 1 shows a schematic diagram of the reactor of embodiment 1.

FIG. 2 shows a schematic diagram of the reactor of embodiment 2.

FIG. 3 is a schematic view of the reactor of embodiment 3.

FIG. 4 is a schematic top view of the reactor of embodiment 3.

Detailed Description

The present invention will be described in further detail below with reference to practice, but the embodiments of the invention are not limited thereto.

Example 1

A three-dimensional electro-fenton reactor arranged laterally as shown in figure 1: sewage and wastewater enter from a water inlet (1), the water inlet is accompanied with an aeration device (2), and the sewage and wastewater flow upwards through a supporting layer (3) and then enter the main body part of the three-dimensional electro-Fenton reactor: the particle electrodes (4) become microelectrodes under the action of the electrode plates (5) and (6), so that the removal rate of organic matters is effectively improved. However, during the back flushing process, the reactor is blocked, the current efficiency is low and the particle electrode is hardened due to scaling on the cathode plate. When the solution provided by the invention is used, the current commutator (8) is used for exchanging the cathode and the anode during back washing, and the reactor is subjected to gas washing for 5-8 minutes; flushing for 7-10 minutes by using gas-water combination; and (5) washing for 8-10 minutes, and finally exchanging the cathode and the anode again. A large number of experimental phenomena prove that after a reactor which is used for a long time uses the back washing method provided by the invention, the scale on the surface of the cathode is obviously reduced, and after the newly-built reactor uses the back washing method provided by the invention, the scale on the cathode is not obviously deposited.

Example 2

The three-dimensional electrochemical biological filter tank which is longitudinally arranged is shown in the attached figure 2: sewage and wastewater enter from the water inlet (1), flow upwards through the supporting layer (2) and enter the main body part of the electrochemical biological aerated filter: the granular biological filter material (4) becomes a microelectrode under the action of the electrode plate (5), so that the removal rate of the organic matters difficult to biodegrade is effectively improved. However, during the back flushing process, the scaling on the cathode plate often causes uneven water and gas distribution, the back flushing strength of a local area is too high, the water distribution often has hysteresis, the local area close to the air inlet end firstly distributes water and gas and even the strength far exceeds the designed strength, and the water and gas distribution of other areas has obvious hysteresis and extremely uneven strength. When the backwashing method provided by the invention is used, the current commutator (7) is used for exchanging the cathode and the anode during backwashing, and the reactor is subjected to gas washing for 5-8 minutes; flushing for 7-10 minutes by using gas-water combination; and (5) washing for 8-10 minutes, and finally exchanging the cathode and the anode again. A large number of experimental phenomena prove that after a reactor which is used for a long time uses the solution provided by the invention, the scale on the surface of the cathode is obviously reduced, and after a newly-built reactor uses the back washing method provided by the invention, the scale on the cathode is not obviously deposited.

Embodiment 3

The annular enlarged anode electrochemical biological filter tank shown in the attached figure 3 is shown in the attached figure 4 in a top view of the reactor: sewage and wastewater enter from a water inlet (1), the water inlet is accompanied with an aeration device (2), and the sewage and wastewater flow upwards through a supporting layer (3) and then enter the main body part of the electrochemical biological aerated filter: the granular biological filter material (4) becomes a microelectrode under the action of the electrode plates (5) and (6), so that the removal rate of the organic matters difficult to biodegrade is effectively improved. However, during the back washing process, the scale on the central cathode column causes excessive deposition to the lower part of the reactor, which causes the problems of reactor blockage, low current efficiency, hardening of particle electrodes, mixed bed of the support layer and the filter material layer, and the like. When the solution provided by the invention is used, the current commutator (8) is used for exchanging the cathode and the anode during back washing, and the reactor is subjected to gas washing for 5-8 minutes; flushing for 7-10 minutes by using gas-water combination; and (5) washing for 8-10 minutes, and finally exchanging the cathode and the anode again. A large number of experimental phenomena prove that after a reactor which is used for a long time uses the back washing method provided by the invention, the scale on the surface of the cathode is obviously reduced, and after the newly-built reactor uses the back washing method provided by the invention, the scale on the cathode is not obviously deposited.

The above description is provided for further details of the present invention with reference to specific embodiments, but it is not intended to limit the present invention to these examples. For those skilled in the art to which the invention pertains, numerous simplifications or substitutions may be made without departing from the spirit of the invention, which shall be deemed to be within the scope of the invention.

Claims

1. A method of addressing electrochemical cathode scaling, comprising: the electrochemical treatment process can be regularly back-flushed, and the cathode and the anode are exchanged, gas-washed, gas-water combined washed and water-washed in sequence during back flushing, and finally the cathode and the anode are exchanged again.

2. A method of addressing electrochemical cathode fouling according to claim 1, wherein: the method for controlling the exchange process of the electrodes in the reactors is to arrange a commutator for exchanging the electrodes at the power supply of each reactor or to manually exchange the electrodes.

3. A method of addressing electrochemical cathode fouling according to claim 1, wherein: the voltage intensity in the reaction system during back flushing is 30-100V.

4. A method of addressing electrochemical cathode fouling according to claim 1, wherein: the air washing time is 5-8 minutes during back washing; the air washing strength is 12L-16L/m²•s。

5. A method of addressing electrochemical cathode fouling according to claim 1, wherein: the gas-water combined flushing time is 7-10 minutes during backwashing; the air washing strength is 12L-16L/m²S; the water washing intensity is 4L-6L/m²•s。

6. A method of addressing electrochemical cathode fouling according to claim 1, wherein: the washing time is 8-10 minutes during back washing; the water washing intensity is 4L-6L/m²•s。

7. A method of addressing electrochemical cathode fouling according to claim 1, wherein: the back flushing interval is 5-12 days.