CN102807268A - Electrolysis method and device for self-cleaning carbon electrode - Google Patents

Abstract

The invention relates to an electrolysis method and device for a self-cleaning carbon electrode, which belongs to the technical field of electrochemical electrolysis, and adopts a periodic steering electrolysis device, which includes: an electrolytic cell, a periodic steering controller, a DC power supply system, and a positive electrode for the electrolytic cell The negative electrode is a carbon electrode, and the periodic steering controller realizes the cyclic operation of energization-disconnection-turning energization-disconnection. The electrolysis method includes the following steps: 1) The material is introduced into the electrolytic cell, and the conductivity of the electrolytic material should be greater than 0.1S /m; 2) Adjust cycle steering controller; 3) Conduct electrolytic redox reaction with electricity, the method and its device can realize self-cleaning of carbon electrodes in the process of electrolytic redox, reduce concentration polarization, improve electrolysis efficiency, reduce Electrolysis energy consumption, easy industrial implementation.

Description

Electrolysis method and device for self-cleaning carbon electrode

technical field

The invention relates to the technical field of electrochemical electrolysis, in particular to an electrolysis method and device for self-cleaning carbon electrodes. the

technical background

The basic principle of electrochemical electrolysis water treatment technology is to generate hydroxyl radicals (OH), ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ), hypochlorite (ClO ^- ), chlorine (Cl ₂ ) or atomic oxygen and other strong oxidants to degrade pollutants in wastewater. Electrochemical electrolysis technology is an advanced oxidation technology. As an "environmentally friendly technology", electrochemical electrolysis treatment has been widely studied and applied in the treatment of some refractory biodegradable pollutants. As a cleaning treatment process, electrochemical electrolysis is highly flexible and can be applied alone or in combination with other treatment methods.

Electrochemical electrolysis is an oxidation-reduction reaction that occurs on the electrode surface. The particularity of this reaction is reflected in the existence of an electric double layer and a surface electric field on the electrode surface. Two types of reaction processes mainly occur on the electrodes, one is the transfer process of charges through the metal-solution interface, and the transfer of electrons realizes oxidation or reduction reactions. Because these reactions are governed by Faraday's law (that is, the amount of chemical reaction caused by the flow of electric current is proportional to the amount of electricity passed), they are called Faraday processes. The other is that at a given electrode-solution interface, a range of potentials will appear where charge transfer does not occur, however, processes such as adsorption and desorption may occur. The structure of the electrode-solution interface can be changed by changing the potential or solution composition, and these processes are called non-Faraday processes. Although charges do not cross the interface in these cases, external currents still flow when the potential, electrode area, or solution composition changes. When an electrode reaction occurs, both faradaic and non-faradaic processes are present. the

Electrochemical electrolysis is an emerging sewage treatment method in recent years. It mainly uses the electrode oxidation-reduction reaction that occurs on the cathode and anode to achieve the purpose of wastewater treatment. A lot of research has been done on the removal of biodegradable organic matter in wastewater by electrochemical methods. Anodizing can be divided into direct oxidation and indirect oxidation. In the direct oxidation process, organic matter is first adsorbed to the surface of the electrode, and then the organic pollutants and some inorganic pollutants are converted into harmless substances through the anodic oxidation reaction; The reaction other than the reaction oxidizes the treated pollutants and finally transforms them into harmless substances. For direct anodic oxidation, the electrochemical surface reaction is limited by the mass transfer step if the reactant concentration is too low; for indirect oxidation, there is no such limitation. According to the degree of oxidation of the oxidized substance, the direct oxidation method is divided into two categories: one is electrochemical conversion, that is, the oxidized substance is partially oxidized. For organic pollutants, electrochemical conversion can convert toxic substances into non-toxic substances, or convert refractory organic substances into biodegradable substances; the second is electrochemical combustion, that is, the oxidized substances are completely oxidized into inorganic substances , such as CO ₂ and H ₂ O.

Cathodic reduction is to use cathodic reduction reaction to reduce O ₂ to H ₂ O ₂ with oxidation activity and oxidize organic pollutants. Through the direct reduction of the cathode, water can be discharged on the surface of the cathode to generate adsorbed hydrogen atoms and undergo a substitution reaction with the halogenated hydrocarbon molecules adsorbed on the surface of the cathode to dehalogenate them. Cathodic reduction can treat a variety of pollutants and is also a method of recovering valuable materials.

The process of direct and indirect electrochemical electrolysis is not absolute. In fact, the direct and indirect electrolysis reactions of organic matter often occur at the same time. Using the strong oxidizing free radicals generated on the surface of the electrode, organic matter can be oxidized without selection; and through the control of the electrocatalytic activity of the electrode, the organic matter can be degraded and oxidized to a certain stage, so that the electrochemical conversion can be controlled at complete degradation Or partial degradation, is the most attractive and challenging application of electrochemical methods. the

The utility model with the application number 200820157652.6 relates to an electrolytic oxidation device for refractory organic wastewater, which is composed of an electrolytic catalytic oxidation device and a power supply assembly. The electrolytic catalytic oxidation device includes a water inlet pipe, a water outlet pipe, an electrolytic cell and an electrode plate assembly. Ti/RuO2+TiO2 mesh ternary electrode, the distance between cathode and anode plates is 20cm. When working, the direct oxidation of the anode and the indirect oxidation in the solution are used to oxidize the pollutants in the solution, as long as there is enough water in the electrolytic cell A more stable treatment effect can be achieved by adjusting the electrode-to-water ratio and current density. The anode used in the utility model is expensive, the cost of industrialization is high, and the coating is easy to fall off and fail, so the industrialization is difficult. the

The invention with application number 200910050788.6 relates to an integrated electrolytic nitrogen and phosphorus removal wastewater treatment method, which realizes the removal of nitrogen, phosphorus nutrients and organic pollutants in wastewater in the same electrolytic cell. Graphite and iron plates are used as electrodes, and the electrolytic dephosphorization and electrolytic denitrification processes are alternately changed by intermittently changing the polarity of the electrodes, thereby removing nitrogen, phosphorus nutrients and organic pollutants in wastewater. The invention is optimized and integrated according to the characteristics of changes in parameters such as electrolysis time, current density, pH value, and pollutant removal rate in the process of electrolytic phosphorus removal and electrolytic nitrogen removal. Nitrogen, phosphorus nutrients and organic matter, it has the characteristics of small footprint, short treatment time and high pollutant removal efficiency. It is characterized in that it includes the following steps: 1) placing 1-2 rows of electrodes in the electrolytic cell, with a total of 4-20 pairs of electrodes, each pair of electrodes is composed of iron plate electrodes and graphite electrodes; the waste water is introduced into the electrolytic cell through the water inlet pipe, Turn on the aeration device at the bottom of the electrolytic cell; 2) First, use the graphite electrode as the anode and the iron plate electrode as the cathode to perform electrolytic denitrification treatment on the wastewater; when the pH value of the solution is lower than 5, change the direction of the current so that the iron plate electrode is the anode , the graphite electrode is the cathode, and the wastewater is electrolytically dephosphorized; when the pH value of the solution is higher than 8, the direction of the current is changed again; the process of electrolytic denitrification and electrolytic dephosphorization is repeated for 2-3 times; Always maintain between 5 and 8; 3) After the treatment, turn off the aeration device and let it stand for 10-20 minutes; 4) Open the valve to discharge the deposited sludge from the sludge discharge pipe, and drain through the drain pipe at the same time. This invention adopts aeration at the bottom of ^the electrolytic cell, because the air bubbles will increase the resistance of the waste water, which will increase the power consumption of the electrolysis. will increase its power consumption. In this invention, the electrode polarity is changed intermittently after the pH of the solution changes, and it generally takes 20 to 120 minutes.

The application number is 200610040664.6, which discloses a method for electrolytically degrading aniline or/and nitrobenzene in wastewater. It uses an electrolytic cell separated by a cation exchange membrane in the middle, and the anode chamber is filled with aniline or/and nitrobenzene and salt. Dilute NaOH solution is added to the cathode chamber, which is circulated by circulating pumps respectively. The anode material is titanium-based coated with ruthenium or titanium-based coated with lead dioxide, and the cathode material is stainless steel or graphite. Direct current electrolysis, aniline or/and Nitrobenzene is removed by oxidative degradation. At the same time, the cations dissociated from the salt in the wastewater pass through the cation exchange membrane and enter the cathode chamber under the action of a direct current electric field, and combine with ^OH- to form hydroxides. The raw wastewater plays the role of desalination, which is beneficial to the subsequent biochemical treatment unit. After the feed liquid in the anode chamber and cathode chamber circulates for a certain period of time, samples are taken. When the concentration of aniline or/and nitrobenzene in the feed liquid in the anode chamber drops to the required value, the operation is stopped and the feed liquid is released. In this invention, the diaphragm compartment electrolyzer used in the chlor-alkali industry is adopted. The salt water electrolyzed in the chlor-alkali industry needs to be processed through various processes, and there are many impurities in the waste water, such as salts and organic matter, which are easy to cause the diaphragm to plug. It is impossible to treat waste water like the chlor-alkali industry. Therefore, industrialization of this method is not easy to realize.

The Chinese patent application number 03151224.0 discloses an electrolytic oxidation treatment process for phenol-containing wastewater, which belongs to the non-stirring, internal circulation, double-cooperative electrolytic oxidation treatment process for refractory organic wastewater in environmental electrochemistry, especially for phenol-containing wastewater electrolytic oxidation treatment process. The internal circulation plate and frame electrolytic cell is adopted, the Ti-based _PbO2 electrode is used as the anode, the stainless steel is used as the cathode, and the wastewater containing phenol is used as the electrolyte. Through electrolysis, the discharge on the anode produces strong oxidizing groups hydroxyl radicals ( OH), The cathode obtains electrons to form H ₂ O ₂ , and the synergistic effect of the cathode and the anode realizes the deep oxidation and decomposition of phenol pollutants, and then achieves the purpose of treating phenol-containing wastewater. The anodes and cathodes are alternately arranged, the number of cathode plates is one more than the number of anode plates, and the distance between adjacent plates is 20mm. The electrolytic power supply adopts a regulated DC power supply with a current density of 30mA/cm ² .

The Chinese patent application number 02223848.4 discloses a pulse cycle electrolytic air flotation type sewage treatment device, which adopts a baffled electrolytic air flotation chamber, and an electrode group with a segmented multi-electrode structure is arranged in the air flotation chamber. The group is a convex-concave or evenly distributed W-shaped structure. The electrode group is composed of a stainless steel wire mesh anode with low overpotential and a cathode made of graphite material and an electrode separator. The distance between the electrode plates is 1.8mm to 2.5mm. The utility model has the advantages of simple structure, less land occupation and no moving parts. The microbubble density is high, the bubble diameter is small, the energy consumption is small, and the treatment efficiency is high. Electrode loss is small, not easy to passivation, sludge treatment is convenient, no dehydration and concentration treatment is required, the programmable controller's segmented multi-electrode pulse cycle power supply mode is adopted, and the magnetic flux leakage protection voltage regulating transformer is adopted. The electrical system is safe and reliable, and the operation is easy. The control is simple, it is a new type of electrolytic air flotation sewage treatment device, used in the treatment of industrial wastewater such as pharmaceuticals, printing and dyeing, papermaking and chemical industry. the

The Chinese patent with the application number 200620032114.5 discloses an electrochemical reactor with reverse pole operation, which is composed of at least two grid-like anode groups and two grid-like cathode groups, one of which is connected to a grid-like anode group The cathode groups are inserted and arranged on a plane or arc surface to form a composite electrode group A, and another grid-shaped anode group and another grid-shaped cathode group are also arranged in a corresponding plane or arc surface to form a composite electrode group B. The grid-like anode group and the grid-like cathode group in a composite electrode group are alternately energized and do not work at the same time; in the adjacent composite electrode group, the two grid-like anode groups are also alternately connected to positive direct current and do not work at the same time; When direct current is applied, it can achieve air flotation to remove suspended solids in water medium, electrocatalytically oxidize wastewater COD, soften hardness (Ca ²⁺ , Mg ²⁺ ) in water medium, remove most ions in water, and kill bacteria in water medium by electrolysis The role of algae.

Since the 1980s, people have conducted extensive research on the treatment of refractory organic matter by electrochemical electrolysis, and it has been proved by experiments to be the most effective means. Among them, the operating conditions such as electrode catalytic characteristics, electrode structure and electrochemical reactor structure are the most important factors that affect the electrolytic process. important factor in chemical oxidation efficiency. Direct electro-oxidation usually adopts relatively high current density, such as greater than 100A/m ² , and the electrodes should not adhere to pollutants. However, when the electric redox conversion usually adopts a lower current density, such as less than 100A/m ² , polymers are often attached to the electrode surface, which affects the electrolysis efficiency. In addition, as the electrolysis proceeds, the materials near the electrolysis will continue to be consumed, and the current or voltage will continue to rise, resulting in concentration polarization and increased power consumption. In the industry, forced turbulence or enhanced stirring are often used to eliminate it, but it also consumes energy. How to eliminate electrode pollution, reduce concentration polarization, improve electrolysis efficiency, reduce electrolysis energy consumption, and facilitate industrial implementation are the difficulties and key points in the application of electrochemical electrolysis technology to water treatment.

It can be seen that in order to improve the efficiency of electrochemical electrolysis technology and reduce energy consumption, it is necessary to eliminate electrode pollution and realize electrode self-cleaning, which is the purpose of the present invention. the

Contents of the invention

The purpose of the present invention is to provide a self-cleaning carbon electrode electrolysis method and device, the method can realize the self-cleaning of the carbon electrode in the electrolytic redox process, reduce concentration polarization, improve electrolysis efficiency, reduce electrolysis energy consumption, and facilitate Industrial implementation. the

The object of the present invention is achieved in this way: a kind of electrolysis method of self-cleaning carbon electrode, has adopted period to turn to electrolysis device, and this device comprises: electrolyzer, period turns to controller, DC power supply system, and the positive and negative electrode of electrolyzer is carbon Electrode, periodic steering controller realizes energization-disconnection-turning energization-disconnection cycle operation, the electrolysis method includes the following steps: 1) Introduce the material into the electrolyzer, the conductivity of the electrolyzed material should be greater than 0.1S/m, adjust The pH value is 0.5 to 12.5; 2) Adjust the cycle steering controller, the steering cycle is 30 to 600 seconds, and the ratio of disconnection time to energization time is 1:1 to 15; 3) The electrolytic redox reaction should be energized, and the current density should be greater than 5A/m ² .

Carbonaceous electrodes are graphite, activated carbon or glassy carbon. The distance between the electrode plates in the electrolytic cell is 1-20 mm. Electrode setups can be in monopolar or bipolar setups. The positive and negative carbonaceous electrodes connected to the power supply of the electrolyzer should be plate or hole plate electrodes. If the carbonaceous repolarization of the repolarization is set in the middle, it can be in the form of plate, block assembly or granular. It is not only beneficial to processing, but also can reduce costs. the

The distance between the plates is set according to the conductivity of the electrolytic material. Generally, if the conductivity is small, the distance between the plates should be small. The greater the conductivity, the distance between the plates can be appropriately increased, which is conducive to saving electric energy. Therefore, the distance between the plates can be greater than 20mm. It's just that the electrolysis needs to consume electric energy in the electrolyte, which increases the power consumption. the

The DC power system is a DC power supply that converts AC to DC, a photovoltaic panel that can directly generate DC power through photoelectric conversion, a storage battery or a fuel cell. the

Experiments show that the cycle steering controller, the self-cleaning effect decreases when the steering cycle is less than 30 seconds and greater than 600, but it is still effective. The ratio of disconnection time to power-on time is 1:1~15, and the self-cleaning effect is not the same in this range Dropped, but still had an effect. The main reason is that if the cycle is too short, the electrolysis time will be short, which is not conducive to the completion of self-cleaning; if the cycle is too long, the electrolysis time will be long, the amount of sediment will be large, the adhesion will increase, and cleaning will be difficult, which will reduce the cleaning effect. the

The electrolytic material can be added with inorganic salt electrolyte to adjust the conductivity. The electrolytic material is usually industrial wastewater, and the conductivity is generally greater than 0.1S/m. When the conductivity is adjusted to be higher, the resistance will be reduced and electricity will be saved. The inorganic salt electrolyte is preferably sodium sulfate. In general, it is better to add less electrolyte to increase the conductivity, because adding electrolyte will increase the cost, and if the added electrolyte is not removed, the waste water will increase the environmental burden after discharge, such as the removal cost is relatively large. the

Inorganic acids and inorganic bases should be used to adjust the pH value. The inorganic acid is preferably sulfuric acid, and the inorganic base is preferably sodium hydroxide. Of course other inorganic acids and bases can also be used. The pH value of wastewater is generally between 0.5 and 12.5. It is also acceptable when it is less than 0.5 or greater than 12.5, but the requirements for the auxiliary equipment of the electrolytic cell are relatively high. From the perspective of reducing the cost of the electrolytic cell, it is most beneficial to be near neutral, and it is best to control it at 4~ 10 or so. the

This technical method can be applied in the electrolysis process applied in the technical background and other electrolytic wastewater treatment processes. What needs to be changed is to replace the positive and negative electrodes with carbon electrodes, which should be homogeneous, which can be used as anodes or As a cathode, similar to hands, it can also be called chiral electrolysis. the

The DC power supply system usually uses a DC power supply that converts AC to DC, which is a commercially available commodity. Because the present invention uses direct current, in order to protect the environment, solar energy can be used, and photovoltaic panels that directly generate direct current through photoelectric conversion can be used to power the electrolysis, which is more conducive to environmental protection. Since there is no need for conversion and storage, there is no input of converters and batteries, which can significantly save investment and reduce power consumption costs. If continuous wastewater treatment is required, photovoltaic panels can be used for power supply when there is sunlight. DC power is used at other times, and storage batteries or fuel cells can also be used. the

The cycle steering controller is produced by Beijing Fengyuan Tenglong Technology Development Co., Ltd. The electrolytic cell is an electrolytic cell for the electrolysis of wastewater, which can be operated intermittently or continuously. It is better to have a material circulation system, an air stirring system, or a mechanical stirring system for the batch operation electrolyzer. The continuous operation electrolytic cell should have a material conveying system to maintain the continuous flow of the material. Each electrolytic cell can also be equipped with a material circulation system, or an air stirring system, or a mechanical stirring system. the

The intermittent current steering control system adopted in the present invention, through the cyclic operation of energization-disconnection-steering energization-disconnection, makes each pole plate continuously serve as cathode and anode. When used as an anode, the pole plate is prone to passivation, and The polymer produced by electrolysis is attached, and the nearby materials are consumed at the same time, and the passivation layer will disappear quickly when it is used as the cathode, and the polymer attached to the surface of the electrode will be removed due to hydrogen evolution, and enter the electrolyte to realize the self-cleaning of the electrode Function, when the current density is less than 5A/m ² , the generation of hydrogen is very weak, and the self-cleaning effect is not good. When the current density is greater than 150A/m ² , the electrolytic oxidation reaction is strong, and it is difficult for polymer to adhere. In addition, even if the material is not well stirred or flowed, the material near the electrode will be alternately consumed due to the inverted pole, and the concentration polarization caused by poor stirring will be eliminated. The disconnection operation is adopted between energization and turning energization, so that the charged layer of the plate has a certain buffer, which can weaken the capacitive effect of the electric double layer, avoid charge neutralization and power consumption, and improve the utilization efficiency of the charge.

The electrolysis method and its device of the present invention, through energization-disconnection-turning energization-disconnection cycle operation, make the electrode generate hydrogen evolution, remove the polymer attached to the carbon electrode; make the direction of the electrode electric field constantly change, which can promote and improve the charged particles. Flow, improve the liquid phase mass transfer process, reduce the concentration polarization; at the same time weaken the capacitive effect of the electric double layer. Finally, self-cleaning in the electrolysis process with carbon electrodes is realized, which makes the electrolysis operation more convenient, facilitates industrial application, and improves the electrolysis efficiency, thereby reducing the energy consumption of electrolysis. the

The purpose of the present invention, technical scheme and effect will be described in detail in conjunction with embodiment. the

Description of drawings

Accompanying drawing is the composition schematic diagram of device of the present invention;

In the figure: 1. AC to DC power supply, 2. Photovoltaic panels for photoelectric conversion, 3. Cycle steering controller, 4. Electrolyzer. the

Detailed ways

Example 1.

As shown in the attached figure, the electrolysis of the self-cleaning carbon electrode adopts a periodic steering electrolysis device, including: an electrolytic cell 4, a periodic steering controller 3, and a DC power supply system 1. The positive and negative electrodes of the electrolytic cell are carbon electrodes, and the periodic steering The controller realizes the cyclic operation of energization-disconnection-turning energization-disconnection. The carbonaceous electrode is graphite, with a thickness of 5mm and a distance of 1mm. Equipped with a bubbling device, the material is stirred by air bubbling. The DC power supply system is a DC power supply that converts AC to DC. The cycle steering controller is produced by Beijing Fengyuan Tenglong Technology Development Co., Ltd. the

Electrolysis method: 1) Introduce the material dye industrial wastewater into the electrolytic cell 4, the COD is 1.5g/L, the conductivity of the electrolyzed material is 0.1S/m, and the pH value is 0.5; 2) Adjust the cycle to the controller, and the cycle is 30 seconds, the ratio of off time to energization time is 1:1; 3) energize for electrolytic redox reaction, and the current density is 5A/m ² .

After 2 hours of electrolysis, take out the middle electrode plate, wash and dry it with deionized water, and observe it with an electron microscope at 5000 times. It can be seen that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption. The positive and negative poles of each electrode plate should be switched every 30 seconds. One side of the electrode after the experiment is the same as the new electrode, indicating that the polluted electrode surface has achieved self-cleaning. the

Example 2

The difference from Example 1 is that the distance between the carbonaceous electrodes is 5 mm, and 5 sets of pole plates are placed on the electrodes. the

In the electrolysis method, the conductivity of the electrolytic material is adjusted to 0.4S/m with sodium sulfate, and the pH value is adjusted to 1.5 with sodium hydroxide; the cycle is adjusted to the controller, the cycle is 60 seconds, and the ratio of disconnection time to energization time is 1 : 3; the electrolytic current density is 15A/m ² .

After 4 hours of electrolysis, take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and there is polymer adsorption on the other side.

Example 3

The difference from Example 1 is that the distance between the carbonaceous electrodes is 10 mm, and 10 sets of pole plates are placed on the electrodes. the

In the electrolysis method, the conductivity of the electrolytic material is adjusted to 0.9S/m with sodium sulfate, and the pH value is adjusted to 4.5 with sodium hydroxide; the cycle is adjusted to the controller, the cycle is 120 seconds, and the ratio of disconnection time to energization time is 1 : 6; the electrolytic current density is 35A/m ² .

After 6 hours of electrolysis, take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and there is polymer adsorption on the other side.

Example 4

The difference from Example 1 is that the distance between the carbonaceous electrodes is 20 mm, and 10 sets of pole plates are placed on the electrodes. the

In the electrolysis method, the conductivity of the electrolytic material is adjusted to 1.3S/m with sodium sulfate, and the pH value is adjusted to 6.5 with sodium hydroxide; the cycle is adjusted to the controller, the cycle is 350 seconds, and the ratio of disconnection time to energization time is 1 : 10; the electrolytic current density is 50A/m ² .

After 6 hours of electrolysis, take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and there is polymer adsorption on the other side.

Example 5

The difference from Example 1 is that the COD of the dye industry wastewater is 15g/L, and the pH value is 12.5; the distance between the carbonaceous electrodes is 10mm, and 10 sets of plates are placed on the electrodes. the

In the electrolysis method, adjust the cycle steering controller, the steering cycle is 500 seconds, the ratio of disconnection time to energization time is 1:13; the electrolysis current density is 90A/m ² .

After 6 hours of electrolysis, pour out the material and then electrolyze 4 batches, take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption.

Example 6

The difference from Example 1 is that the COD of the dye industry wastewater is 15g/L, and the pH value is 12.5; the distance between the carbonaceous electrodes is 10mm, and 10 sets of plates are placed on the electrodes. the

In the electrolysis method, use 20% sulfuric acid to adjust the pH value to 10, adjust the cycle steering controller, the steering cycle is 600 seconds, the ratio of disconnection time to power-on time is 1:15; the electrolysis current density is 120A/m ² .

After 6 hours of electrolysis, pour out the material and then electrolyze 4 batches, take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption.

Example 7.

As shown in the attached figure, the electrolysis of the self-cleaning carbon electrode adopts a periodic steering electrolysis device, including: an electrolytic cell 4, a periodic steering controller 3, and a DC power supply system 1. The positive and negative electrodes of the electrolytic cell are carbon electrodes, and the periodic steering The controller realizes the cyclic operation of energization-disconnection-turning energization-disconnection. The carbonaceous electrode is graphite, with a thickness of 8mm and a distance of 3mm. It adopts double pole setting, and places 10 plates as a group. It adopts intermittent operation mode. The materials in the electrolytic tank are pumped and circulated. The DC power supply system is a photovoltaic panel that can directly generate DC power through photoelectric conversion. The cycle steering controller is produced by Beijing Fengyuan Tenglong Technology Development Co., Ltd. the

Electrolysis method: 1) Introduce the material dinitrotoluene wastewater into the electrolytic cell 4, the COD is 3.5g/L, the conductivity of the electrolyzed material is 0.95S/m, and the pH value is 8.5; 2) Adjust the cycle to the controller, and the cycle to 200 seconds, and the ratio of off time to energization time is 1:5; 3) Electrolytic redox reaction is carried out when energized, and the current density is 50A/m ² .

After 5 hours of electrolysis, take out the middle electrode plate, wash and dry it with deionized water, and observe it with an electron microscope at 5000 times. It can be seen that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption. The positive and negative poles of each electrode plate should be switched every 200 seconds. One side of the electrode after the experiment is the same as the new electrode, indicating that the polluted electrode surface has achieved self-cleaning. the

Example 8

The difference from Example 7 is that the distance between the carbonaceous electrodes is 15 mm. the

In the electrolysis method, use 20% sodium hydroxide to adjust the pH value to 10, adjust the cycle steering controller, the steering cycle is 400 seconds, the ratio of disconnection time to power-on time is 1:10; the electrolysis current density is 80A/m ² .

After 3 hours of electrolysis, pour out the material and then electrolyze 4 batches, take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption.

Example 9

The difference from Example 7 is that the carbonaceous electrode is a glassy carbon electrode. the

In the electrolysis method, use 20% sulfuric acid to adjust the pH value to 4, adjust the cycle steering controller, the steering cycle is 300 seconds, the ratio of disconnection time to power-on time is 1:3; the electrolysis current density is 150A/m ² .

After 2 hours of electrolysis, pour out the material and then electrolyze 10 batches, take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption. the

Example 10.

As shown in the attached figure, the electrolysis of the self-cleaning carbon electrode adopts a periodic steering electrolysis device, including: an electrolytic cell 4, a periodic steering controller 3, and a DC power supply system 1. The positive and negative electrodes of the electrolytic cell are carbon electrodes, and the periodic steering The controller realizes the cyclic operation of energization-disconnection-turning energization-disconnection. The carbonaceous electrode is graphite, the thickness is 8mm, and the distance is 3mm. The materials in the electrolyzer are fed continuously by pumping, the DC power supply system is a battery, and the cycle steering controller is produced by Beijing Fengyuan Tenglong Technology Development Co., Ltd. the

Electrolysis method: 1) Introduce the material dinitrotoluene wastewater into the electrolytic cell 4, the COD is 3950mg/L, the conductivity of the electrolyzed material is 0.9S/m, and the pH value is 7.8; 2) Adjust the cycle steering controller, and the steering cycle is 150 seconds, the ratio of off time to energized time is 1:8; 3) Electrolytic redox reaction is carried out by energizing, and the current density is 40A/m ² .

After continuous electrolysis for 48 hours, take out the middle electrode plate, simply wash and dry it with deionized water, and observe it with an electron microscope at 5000 times. It can be seen that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption. The positive and negative poles of each electrode plate should be switched every 150 seconds. One side of the electrode after the experiment is the same as the new electrode, indicating that the polluted electrode surface has achieved self-cleaning. the

Example 11

The difference from Example 10 is that the carbonaceous electrode is a glassy carbon electrode. the

In the electrolysis method, use 20% sulfuric acid to adjust the pH value to 5, the ratio of off time to energization time is 1:3; the electrolysis current density is 110A/m ² .

Take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption. the

Example 12

The difference from Example 10 is that the carbonaceous electrode is a glassy carbon electrode. the

In the electrolysis method, use 20% sodium hydroxide to adjust the pH value to 9, the ratio of off time to energization time is 1:4; the electrolysis current density is 70A/m ² .

Take out the middle electrode plate, you can see that one side of the electrode is the same as the new electrode, and the other side has polymer adsorption. the

Claims (8)

1. The electrolysis method of a kind of self-cleaning carbon electrode is characterized in that adopting period turns to electrolysis device, and this device comprises: electrolyzer, period turns to controller, DC power supply system, and the positive and negative electrode of electrolyzer is carbonaceous electrode, period The steering controller realizes the cyclic operation of energization-disconnection-steering energization-disconnection. The electrolysis method includes the following steps: 1) Introduce the material into the electrolyzer, the conductivity of the electrolyzed material should be greater than 0.1S/m, and adjust the pH value to 0.5 ～12.5; 2) Adjust the cycle steering controller, the steering cycle is 30-600 seconds, the ratio of disconnection time to power-on time is 1:1-15; 3) Power on for electrolytic redox reaction, the current density should be greater than 5A/m ² . 2. according to the electrolysis method of self-cleaning carbon electrode as claimed in claim 1, it is characterized in that carbonaceous electrode is graphite, gac or glassy carbon. 3. The electrolysis method of the self-cleaning carbon electrode according to claim 1, characterized in that the distance between the electrode plates in the electrolytic cell is 1-20mm. 4. According to the electrolysis method of the self-cleaning carbon electrode as claimed in claim 1, it is characterized in that the DC power supply system is a DC power supply of alternating current to direct current, a photovoltaic panel, a storage battery or a fuel cell that can directly generate direct current for photoelectric conversion. 5. According to the electrolysis method of the self-cleaning carbon electrode as claimed in claim 1, it is characterized in that the electrolytic material can be added with an inorganic salt electrolyte to adjust the conductivity. 6. according to the electrolysis method of self-cleaning carbon electrode described in claim 5, it is characterized in that electrolyte is sodium sulfate. 7. According to the electrolysis method of the self-cleaning carbon electrode as claimed in claim 1, it is characterized in that inorganic acid and inorganic alkali should be used to adjust the pH value. 8. According to the electrolysis method of the self-cleaning carbon electrode described in claim 7, it is characterized in that adjusting pH value adopts inorganic acid to be sulfuric acid, and inorganic base is sodium hydroxide. the

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