Internal aeration type organic wastewater treatment device and method

Abstract

The invention discloses an internal aeration type organic wastewater treatment device, which is characterized by comprising an electrolytic bath, an aeration device, a water tank, a water inlet pipe, a water outlet pipe, a water outlet pipe and a water outlet pipe, and the electrolytic bath is internally provided with an anode plate and a cathode plate; the aeration device is arranged close to the anode plate; a positive electrode and a negative electrode of the direct-current power supply are respectively connected with the positive plate and the negative plate; an air pump; wherein a cavity is formed in the negative plate, and the cavity is connected with the air pump, so that air is introduced into the negative plate through the air pump. The device is simple in structure, the technological process is simplified, energy consumption and cost are reduced, and the removal efficiency of organic pollutants can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of organic wastewater treatment, and in particular to an internal aeration type organic wastewater treatment device and method. Background Art

[0002] With the development of society, industry is becoming more and more developed. However, a large amount of organic wastewater is usually generated in the industrial production process. These organic substances may include petroleum, lipids, benzene, alcohols, organic acids, ketones, aldehydes, ethers, esters and amines. They mainly come from chemical, pharmaceutical, papermaking, food processing, agricultural breeding, coating, textile printing and dyeing and other industries. The organic substances contained in these organic wastewaters may cause eutrophication of water bodies and destroy the ecological balance. In addition, organic wastewater is extremely difficult to biodegrade and has strong toxicity. If it is not properly treated, it will directly or indirectly pose a serious threat to the environment and human health. Therefore, the effective treatment of organic wastewater is not only a need to comply with laws and regulations, but also a key measure to protect the environment, maintain ecological balance, ensure human health and achieve sustainable development.

[0003] At present, air-assisted electrocatalytic water treatment technology has the advantages of fast reaction rate, strong mineralization ability, and easy automatic control, and is often used to remove organic pollutants. The current research focus is to improve the electrocatalytic activity by developing new electrode materials, thereby enhancing the pollutant removal effect. The two most common technologies are electrocatalytic oxidation and wet oxidation.

[0004] The wet oxidation wastewater treatment method is a very efficient method for treating high-concentration organic wastewater. It uses air or oxygen as an oxidant to efficiently oxidize and degrade organic matter in the water under high temperature (120-350°C) and high pressure (0.5-20MPa). In order to further improve the efficiency of oxidation degradation and reduce the energy consumption of the reaction, a catalyst is often added in the process. Most of the catalysts used in this process are precious metal catalysts (Pt, Ru), which are relatively expensive. At the same time, in the actual wastewater treatment process, they often contain a high salt content. The high concentration of inorganic salts in the wastewater is not only easy to cause catalyst deactivation, but also easy to cause scaling and other phenomena. In addition, the degradation and removal effect of wet oxidation of organic wastewater containing ammonia nitrogen is often poor.

[0005] Electrocatalytic oxidation wastewater degradation methods usually convert electrical energy into chemical energy of active free radicals through electrodes at room temperature and pressure, and then degrade organic matter by free radicals, or directly cause redox reactions on the electrode surface to achieve degradation of organic pollutants. However, at room temperature and pressure, the concentration polarization phenomenon on the electrode surface will greatly limit the catalytic degradation of pollutants on the surface of the electrocatalytic electrode, and there are limitations on the potential of hydrogen and oxygen evolution, so the pollutant removal capacity is limited.

[0006] In addition, there is also a method of combining wet oxidation and electrocatalytic oxidation to treat organic wastewater, but there are also problems such as high operating costs, high operating energy consumption, poor anode life and possible safety hazards. Summary of the invention

[0007] The purpose of the present invention is to solve the technical problems of the above-mentioned prior art in treating organic wastewater, such as high operating energy consumption, high operating cost, complex process and poor treatment effect, and to provide an internal aeration organic wastewater treatment device with a simple structure, simplified process flow, reduced energy consumption and cost, and able to improve the removal efficiency of organic pollutants.

[0008] In order to solve the above technical problems, the present invention is implemented according to the following technical solutions:

[0009] The present invention provides an internal aeration type organic wastewater treatment device, the device comprising:

[0010] An electrolytic cell having an anode plate and a cathode plate;

[0011] an aeration device, wherein the aeration device is disposed close to the anode plate;

[0012] A direct current power supply, wherein the positive electrode and the negative electrode of the direct current power supply are connected to the anode plate and the cathode plate respectively;

[0013] air pump;

[0014] The cathode plate has a cavity inside, and the cavity is connected to the air pump so that air can be introduced into the cathode plate through the air pump.

[0015] As a preferred embodiment, the electrolytic cell is connected to a water inlet pipe and a water outlet pipe, the water inlet pipe has a water inlet valve, and the water outlet pipe is provided with a water outlet valve.

[0016] As a preferred embodiment, the anode plate is one of a ruthenium-titanium anode plate, a carbon-based anode plate or a lead dioxide anode plate.

[0017] As a preferred implementation, the cathode plate is a gas diffusion electrode plate.

[0018] As a preferred embodiment, the current collector layer of the cathode plate is composed of one of porous carbon fibers, carbon cloth, carbon paper or metal mesh.

[0019] As a preferred embodiment, the catalyst layer of the cathode plate is composed of carbon-based material and polytetrafluoroethylene.

[0020] As a preferred embodiment, the thickness of the catalytic layer ranges from 0.1 to 10 mm.

[0021] As a preferred embodiment, the pore size of the aeration device is nanometer-level or micrometer-level.

[0022] The present invention also provides an internal aeration type organic wastewater treatment method, which is implemented based on the above-mentioned internal aeration type organic wastewater treatment device, and the method comprises the following steps:

[0023] (1) passing organic wastewater into an electrolytic cell;

[0024] (2) introducing air into the electrolytic cell through an aeration device so that the anode region where the anode plate in the electrolytic cell is located absorbs oxygen;

[0025] (3) introducing air into the cathode plate of the electrolytic cell through an air pump;

[0026] (4) supplying power to the electrolytic cell through a DC power supply to activate the oxygen in the anode region and generate hydrogen peroxide in the cathode region where the cathode plate is located;

[0027] (5) The organic wastewater treated in steps (1) to (4) is discharged through the outlet pipe in the electrolytic cell.

[0028] As a preferred embodiment, in step (3), after air is introduced into the cathode plate of the electrolytic cell through an air pump, the air-water ratio inside the cathode plate is between 5:1 and 30:1.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention provides an internal aeration type organic wastewater treatment device. In the anode region, on the one hand, an aeration device with a pore size of nanometer level or micrometer level is used to aerate the anode plate, which can quickly add oxygen to the water body. Because of the large specific surface area and slow rising speed of nanobubbles or micrometer level, the dissolved oxygen concentration of water in the anode region is greatly improved. On the other hand, ruthenium-titanium, carbon-based materials or lead dioxide materials are used as anode plates, which can effectively adsorb dissolved oxygen in the solution and promote the reduction of oxygen and the oxidation of organic matter. In addition, an electric field is generated by applying a voltage, and the presence of the electric field helps to further improve the solubility and reaction activity of oxygen, so that the oxygen adsorbed on the electrode surface forms active groups. These active groups can undergo oxidation reactions with organic pollutants in the wastewater and convert them into harmless or low-toxic small molecules, such as carbon dioxide and water.

[0031] In the cathode area, the present invention introduces an air aeration system inside the cathode plate, which transports oxygen to the cathode through the cavity inside the cathode plate. The evenly distributed air micropores inside increase the supply of oxygen. Under the action of air pressure, air and electrolyte form a three-phase interface on the cathode surface, which promotes the oxygen reduction reaction and generates hydrogen peroxide. At the same time, the introduction of air helps maintain the hydrophobicity of the cathode material surface, prevents the cathode from losing its hydrophobicity due to the infiltration of the electrolyte during long-term operation, ensures the continuous and efficient cathode reaction, and thus significantly improves the efficiency of hydrogen peroxide generation. This not only enhances the effect of the electrochemical redox reaction, but also further improves the quality of water treatment. In addition, the method of supplying oxygen inside the cathode plate can effectively reduce the gas-water ratio required for the production of hydrogen peroxide, thereby achieving the purpose of reducing energy consumption and efficient production.

[0032] In addition, on the basis of the original removal of organic pollutants by the cathode and anode, the present invention adopts a single-chamber reactor design without a diaphragm, so that the oxidant (such as superoxide·O2-) generated in the anode region and the reduction product (such as hydrogen peroxide H 2 O 2 ) can directly contact and work synergistically in the same reaction space. This synergistic effect not only reduces the need for external stirring, but also significantly improves the degradation efficiency of complex pollutants, especially showing excellent results in the treatment of difficult-to-degrade organic matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0034] Figure 1 It is a structural diagram of an internal aeration type organic wastewater treatment device of the present invention;

[0035] In the figure:

[0036] 1- anode plate, 2- cathode plate, 3- aeration device, 4- water inlet valve, 5- gas phase valve, 6- water outlet valve, 7- gas phase flow meter, 8- DC power supply, 9- cavity, 10- air pump. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0038] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this specification should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second" and similar words used in this specification and claims do not indicate any order, quantity or importance, but are only used to distinguish different technical features.

[0039] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0040] Organic substances contained in organic wastewater may cause eutrophication of water bodies and destroy ecological balance. Organic wastewater is extremely difficult to biodegrade and highly toxic. If it is not properly treated, it will directly or indirectly pose a serious threat to the environment and human health. The current organic wastewater treatment methods have technical problems such as high operating energy consumption, high operating costs, complex processes, and poor treatment effects.

[0041] In order to solve the above technical problems, the present invention provides an internal aeration organic wastewater treatment device with a simple structure, simplified process flow, reduced energy consumption and cost, and improved removal efficiency of organic pollutants. It has significant technical advantages and economic benefits and has broad application prospects in the field of water treatment.

[0042] The internal aeration type organic wastewater treatment device of the present invention comprises: an electrolytic cell, an aeration device, a direct current power supply and an air pump.

[0043] Specifically, the electrolytic cell has an anode plate and a cathode plate, an aeration device is arranged near the anode plate, and the positive and negative electrodes of a DC power supply are connected to the anode plate and the cathode plate, respectively. The cathode plate has a cavity inside, and the cavity is connected to an air pump so that air is introduced into the cathode plate through the air pump.

[0044] It should be noted that in the air-assisted anode in-situ degradation process, it is crucial to control the aeration flow rate because it directly affects the efficiency and effect of the entire electrochemical oxidation process. The aeration flow rate determines the supply of oxygen, and oxygen is a key factor in the production of strong oxidants such as hydroxyl radicals in electrochemical oxidation, which have extremely high degradation capabilities for pollutants. If the oxygen supply is insufficient, the rate of the oxidation reaction will decrease, affecting the removal efficiency of pollutants; conversely, excessive oxygen supply may lead to energy waste and increased operating costs. Appropriate aeration flow helps to maintain the activity of the electrode surface and avoid the decrease in electrode efficiency due to insufficient oxygen supply. At the same time, controlling the aeration flow rate can prevent the electrode surface from being covered by too many bubbles, which may form a short circuit, reduce the efficiency of the electrochemical reaction, and may even accelerate the corrosion of the electrode material and shorten the service life of the electrode. In the present invention, the aeration device is arranged close to the anode plate. Preferably, a gas phase valve and a gas phase flow meter are provided on the air delivery pipeline of the aeration device, which is conducive to controlling and maintaining an appropriate aeration flow rate, increasing the dissolved oxygen content in the water, and adsorbing oxygen on the anode.

[0045] Preferably, the electrolytic cell is of single-chamber design. This structural design ensures that the reactants at the anode and cathode can fully contact and work synergistically during the electrolysis process, thereby improving the degradation efficiency of pollutants in sewage.

[0046] In one embodiment, the electrolytic cell is connected to a water inlet pipe and a water outlet pipe, the water inlet pipe has a water inlet valve, and the water outlet pipe is provided with a water outlet valve.

[0047] It should be noted that the water inlet pipe is set at the bottom of the reactor and the water outlet pipe is set at the top of the reactor. In this way, the lightly reacted wastewater can flow out from the top, while the heavier unreacted wastewater and the newly entered wastewater remain in the reactor to continue to react, thus prolonging the reaction time of the difficult-to-degrade macromolecular organic matter (heavier substances).

[0048] In a preferred embodiment, the anode plate is one of a ruthenium-on-titanium anode plate, a carbon-based anode plate or a lead dioxide anode plate.

[0049] It should be noted that the ruthenium-titanium anode plate is an electrode material made by a high-temperature oxidation process with a titanium substrate and a precious metal oxide coating mainly composed of ruthenium (Ru) and iridium (Ir) on the surface of the titanium substrate. Ruthenium-titanium anode plates have high current efficiency: Ruthenium-titanium anode plates have high current efficiency, which means that the consumption of electrical energy can be reduced during the electrolysis process. In addition, ruthenium-titanium anode plates exhibit low overpotential in the oxygen evolution reaction, which also helps to reduce energy consumption. Ruthenium-titanium anode plates can work stably in a variety of highly corrosive electrolytic media, and the coating is firmly bonded to the substrate, has strong corrosion resistance, and has excellent corrosion resistance. The ruthenium-titanium anode plate can maintain the electrode spacing unchanged during the electrolysis process, ensuring that the electrolysis operation is carried out under a stable cell voltage, thereby improving the electrolysis efficiency. The ruthenium-titanium anode plate has a long service life, reduces the replacement frequency, and reduces maintenance costs. Compared with graphite electrodes, ruthenium-titanium anode plates can support higher current density, thereby increasing production at the same electrolytic cell volume, and ruthenium-titanium anode plates do not produce harmful byproducts and are environmentally friendly. Ruthenium-titanium anode plates are almost insoluble in the electrolyte and will not pollute the electrolytic medium, ensuring the long-term stable operation of the electrolysis system. Ruthenium-titanium anode plates can also be reused, which can reduce material waste. The present invention uses ruthenium-titanium anode plates as anode plates, which is beneficial to reducing energy consumption and use costs during the treatment of organic wastewater, and increases the stability of system operation.

[0050] It should be noted that the carbon-based anode plate is an electrode plate based on carbon materials, which has good electrical conductivity and helps to improve the electrolysis efficiency. The carbon-based anode plate has a high specific surface area, which can increase the contact area with organic pollutants in wastewater and improve the treatment efficiency. Carbon materials show good stability in a wide range of chemical environments. Therefore, the use of carbon-based anode plates as anode plates has good chemical stability. The carbon-based anode plate has a porous structure, which is conducive to the attachment and growth of microorganisms and the like. Compared with precious metal electrode materials, carbon-based materials are generally lower in cost. Therefore, the use of carbon-based anode plates as anode plates is conducive to reducing the overall treatment cost. The carbon-based anode plate has less impact on the environment and is an environmentally friendly electrode material. The carbon-based anode plate can also be modified by chemical or physical methods to enhance its performance or give it new functions, which is conducive to improving the treatment effect of organic wastewater. The carbon-based anode plate has good corrosion resistance and can resist the erosion of chemical substances in wastewater. Carbon-based materials can be derived from renewable resources, such as biomass. Therefore, the use of carbon-based anode plates as anode plates is conducive to sustainable development.

[0051] It should be noted that the lead dioxide anode plate is an electrode material made of titanium as a substrate, with a lead dioxide (PbO2) coating on the surface of the titanium substrate, and made through a high-temperature oxidation process. The lead dioxide anode plate has a high oxygen evolution potential, which helps to produce oxygen at a lower voltage, thereby reducing energy consumption. The lead dioxide anode plate also has good electrochemical stability, excellent conductivity and strong oxidation ability, which helps to improve the efficiency of electrolysis and can effectively degrade organic pollutants. The lead dioxide anode has a long service life, reducing the replacement frequency and maintenance costs. The lead dioxide anode does not contain harmful ions such as Sn, Sb, Ag, etc., and will not cause secondary pollution to the solution, which is beneficial to environmental protection. During the use of the lead dioxide anode, since there is no shedding of lead sulfate, no precipitation will be generated at the bottom of the electrolytic cell, reducing labor expenses.

[0052] In a preferred embodiment, the cathode plate is a gas diffusion electrode plate.

[0053] It should be noted that the gas diffusion electrode plate is a porous electrode, which is usually used in fuel cells and electrochemical sensors. It is made of a hydrophobic polymer material (such as polytetrafluoroethylene, etc.) as an adhesive for the electrode material, and is made into an electrode with porosity, certain waterproofness, good conductivity, high active surface area and high catalytic activity according to the principle of fuel cells. The gas diffusion electrode plate can provide a larger contact area, which is conducive to the transfer of oxygen from the gas phase to the liquid phase and improves the utilization efficiency of oxygen. The structure of the gas diffusion layer of the gas diffusion electrode plate helps to discharge the reaction product water, prevent the phenomenon of "flooding the electrode", and maintain the long-term stable operation of the electrode. The gas diffusion electrode plate is made of durable materials, has low maintenance costs, and is suitable for long-term use. The gas diffusion electrode plate can also reduce energy loss in the electrolysis process and improve current efficiency. By optimizing the supply of oxygen, the gas diffusion electrode plate helps to reduce energy consumption in the electrochemical process. Using the gas diffusion electrode plate as a cathode plate can also promote the formation of a gas-liquid-solid three-phase interface. Even if there is no external aeration system, the gas diffusion electrode plate can also use oxygen in the air, which simplifies the operation process. The material used for the gas diffusion electrode plate is environmentally friendly and does not produce harmful byproducts. Therefore, the present invention uses the gas diffusion electrode plate as the cathode plate, which can improve the reaction efficiency, improve the treatment effect of organic wastewater, reduce energy consumption, and has a long service life and low maintenance cost.

[0054] Specifically, in this embodiment, a gas diffusion electrode plate is used as a cathode plate, so that the cathode plate has a cavity inside. By inserting a microporous aeration tube of an air pump into the cavity for internal aeration, the dissolution efficiency and transfer efficiency of oxygen can be effectively improved, thereby reducing the amount of air required. This can effectively reduce the gas-water ratio required for the reaction, reduce energy consumption and operating costs, and make the entire system more efficient and environmentally friendly. At the same time, the hydrophobicity of the hydrophobic layer of the cathode plate determines the degree of balance of the three-phase interface. If the hydrophobic layer is too thick, the contact performance between the electrode and the solution decreases, the resistance increases, and the ability to catalyze the reaction of water and oxygen to produce hydrogen peroxide will decrease. When the hydrophobic layer is too thin, the loading amount of the catalyst on the electrode will decrease, and the electrode cannot adsorb oxygen, and the three-phase interface cannot be effectively formed in the reaction. Therefore, after air is introduced into the cathode plate through an air pump, the air pressure will assist the hydrophobic layer to form a three-phase interface at the cathode, and keep the hydrophobic layer of the electrode from losing its hydrophobicity under infiltration. A balanced and stable three-phase interface can improve mass transfer efficiency, enhance reaction kinetics, increase current efficiency, and improve electrocatalyst performance, thereby improving the efficiency of the entire electrochemical system. A balanced and stable three-phase interface can promote the occurrence of redox reactions, help degrade organic pollutants, and convert them into harmless or easy-to-handle substances. A balanced and stable three-phase interface can also reduce the energy input required to achieve the same treatment effect, thereby reducing operating costs. It also helps to reduce side reactions and corrosion problems in the electrochemical system and improve the long-term stability and reliability of the system.

[0055] Preferably, the current collector layer of the cathode plate is made of one of porous carbon fibers, carbon cloth, carbon paper or metal mesh.

[0056] It should be noted that porous carbon fibers have the advantages of high conductivity, good chemical stability and corrosion resistance, and high specific surface area. Carbon cloth is flexible and bendable, and has a certain mechanical strength, which can provide effective gas diffusion and electron transmission channels. Carbon paper has a uniform porous structure, which is conducive to the uniform diffusion of gas. Due to its structural characteristics, it usually has good conductivity and air permeability. The surface smoothness of carbon paper contributes to the uniform distribution of the catalyst. The metal mesh has good conductivity and high mechanical strength, and the flow characteristics of gas and liquid can be controlled by adjusting the mesh size. Therefore, in actual application scenarios, according to specific application requirements and operating conditions, one of porous carbon fibers, carbon cloth, carbon paper or metal mesh is selected as the current collector layer of the cathode plate, which can optimize the gas and liquid transfer efficiency, improve the electrochemical reaction rate, and ensure the long-term stability of the electrode, which is conducive to improving the treatment efficiency of organic wastewater.

[0057] Preferably, the catalytic layer of the cathode plate is composed of carbon-based materials and polytetrafluoroethylene. The catalytic layer composed of carbon-based materials and polytetrafluoroethylene has a high specific surface area, good electrical conductivity, and excellent chemical stability. Polytetrafluoroethylene is a hydrophobic material that helps the transmission of gas in the catalytic layer and reduces the accumulation of liquid water, thereby optimizing the drainage performance of the cathode plate. The hydrophilicity of the catalytic layer helps the reduction of oxygen at the cathode, while the hydrophobicity of polytetrafluoroethylene helps the transmission of oxygen and the removal of water, thereby improving the efficiency of treating organic wastewater. The catalytic layer of this structure also helps to form a stable gas-liquid-solid three-phase interface on the electrode. The carbon-based material also has good mechanical strength, which makes the electrode structure stable and helps to improve the service life of the electrode. Compared with precious metal catalysts, carbon-based materials are generally low in cost, which is conducive to reducing the overall cost of organic wastewater treatment. Carbon-based materials and polytetrafluoroethylene are environmentally friendly materials and will not pollute the environment.

[0058] Preferably, the thickness of the catalytic layer is in the range of 0.1-10 mm.

[0059] In one embodiment, the pore size of the aeration device is nanometer-scale or micrometer-scale. Aeration devices with micrometer-scale or nanometer-scale pores can produce smaller bubbles, and because their surface area to volume ratio is significantly increased, the gas-liquid contact area is increased, thereby improving the dissolution rate of oxygen and the mass transfer efficiency. Secondly, the use of nanometer-scale or micrometer-scale aeration devices can reduce the shielding of the electrode surface by bubbles and avoid the formation of a large number of bubbles covering the electrode surface, which helps to maintain the activity of the electrode and ensure the continuity and efficiency of the electrochemical reaction. At the same time, due to the reduction in the size of the bubbles, they are more likely to break during the rising process, thereby increasing the renewal frequency of the gas-liquid interface and further improving the oxygen transfer efficiency. In addition, the use of aeration devices with micrometer-scale or nanometer-scale pores reduces the risk of clogging because small pores are not easily clogged by particulate matter.

[0060] The present invention also provides an internal aeration type organic wastewater treatment method, which is implemented based on the internal aeration type organic wastewater treatment device of the present invention, and the method comprises the following steps:

[0061] (1) Pass organic wastewater into the electrolytic cell.

[0062] (2) Air is introduced into the electrolytic cell through an aeration device so that the anode region of the electrolytic cell where the anode plate is located absorbs oxygen.

[0063] (3) Air is introduced into the cathode plate of the electrolytic cell through an air pump.

[0064] (4) Power is supplied to the electrolytic cell through a DC power supply to activate the oxygen in the anode region and generate hydrogen peroxide in the cathode region where the cathode plate is located.

[0065] It should be noted that after power is applied, the chemically adsorbed oxygen on the anode is activated by the current, and the generated oxidizing substances react with the organic pollutants in the sewage to degrade the pollutants. At the same time, the cathode efficiently generates hydrogen peroxide (H 2 O 2 ) to degrade pollutants. In addition, the strong oxidant generated at the anode and the hydrogen peroxide generated at the cathode work synergistically in the single-chamber reactor without a diaphragm, enhancing the treatment capacity for pollutants. The products of the anode and cathode can directly interact with each other, producing a stronger redox effect, significantly improving the overall efficiency of water treatment.

[0066] (5) The organic wastewater treated in steps (1) to (4) is discharged through the outlet pipe in the electrolytic cell.

[0067] In one embodiment, in step (3), after air is introduced into the cathode plate of the electrolytic cell through an air pump, the air-water ratio inside the cathode plate is between 5:1 and 30:1.

[0068] It should be noted that, generally, in the cathode process, the dissolution and mass transfer efficiency of oxygen directly affect the generation of hydrogen peroxide and the rate of electrochemical reaction. In order to improve the dissolution efficiency of oxygen, external aeration equipment is usually required, which not only increases the complexity of the system, but also increases energy consumption. For wastewater that is difficult to degrade, a higher gas-water ratio is generally required, such as 40:1 to 60:1. The present invention realizes direct aeration of air inside the cathode plate, which can effectively improve the dissolution and mass transfer efficiency of oxygen, improve energy utilization efficiency, reduce the required gas-water ratio, and thus reduce the overall energy consumption of the system.

[0069] In summary, the present invention provides an internal aeration type organic wastewater treatment device and method, in which the organic wastewater to be treated is passed into an electrolytic cell for electrolysis, and the anode mainly uses electrocatalysis to form active sites for oxygen chemically adsorbed on the catalyst surface, thereby achieving efficient degradation of organic matter. The process of producing hydrogen peroxide by the cathode internal aeration electrode is dominated by a two-electron transfer process, accompanied by a four-electron process reaction. The improvement in the efficiency of this process is mainly due to the fact that the electrode can maintain a large reaction area when immersed in water, and the internal aeration mechanism can continuously renew the gas phase inside the electrode, maintain the stability of the hydrophobic layer, and continuously generate hydrogen peroxide at the three-phase interface. When the two processes are used in coupling, the synergistic effect exhibited can effectively improve the treatment efficiency of organic wastewater, while having low operating costs, low operating energy consumption, and a simple process.

[0070] In a specific embodiment, the water quality data and reaction conditions of the organic wastewater to be treated are shown in the following table:

[0071]

[0072] Under the condition of 3mL / min influent flow rate, the organic wastewater was passed into a single-chamber reactor with a volume of 120mL, and electrolyzed by a DC power supply current. 100ml of wastewater solution containing 100mg / L rhodamine, 100mg / L crystal violet, 100mg / L methylene blue, 100mg / L methyl orange and 3500mg / L COD was taken, and 0.71g Na2SO4 was added to the rhodamine, crystal violet, methylene blue and methyl orange solutions to ensure that they have sufficient conductivity. Then the five wastewater solutions were placed in a small reactor with a volume of 120mL, all of which used a graphite cathode with an area of ​​2.5×3.5cm2 and a thickness of 3mm and a lead dioxide anode, an electrode spacing of 1cm, a pH value of 7, an aeration flow of 0.1L / min, a current density of 15mA / cm2, and a reaction time of 1.5h and 12h. The results showed that the treated wastewater solution met the Class I discharge standard in the Discharge Standard of Water Pollutants for Weaving, Dyeing and Finishing Industries (GB 4287-2012).

[0073] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An internal aeration type organic wastewater treatment device, characterized in that: The device comprises: An electrolytic cell having an anode plate and a cathode plate; an aeration device, wherein the aeration device is disposed close to the anode plate; A direct current power supply, wherein the positive electrode and the negative electrode of the direct current power supply are connected to the anode plate and the cathode plate respectively; air pump; The cathode plate has a cavity inside, and the cavity is connected to the air pump so that air can be introduced into the cathode plate through the air pump.

2. The internal aeration type organic wastewater treatment device according to claim 1, characterized in that: The electrolytic cell is connected with a water inlet pipe and a water outlet pipe, the water inlet pipe is provided with a water inlet valve, and the water outlet pipe is provided with a water outlet valve.

3. The internal aeration type organic wastewater treatment device according to claim 1, characterized in that: The anode plate is one of a ruthenium-titanium anode plate, a carbon-based anode plate or a lead dioxide anode plate.

4. The internal aeration type organic wastewater treatment device according to claim 1, characterized in that: The cathode plate is a gas diffusion electrode plate.

5. The internal aeration type organic wastewater treatment device according to claim 4, characterized in that: The current collector layer of the cathode plate is composed of one of porous carbon fibers, carbon cloth, carbon paper or metal mesh.

6. The internal aeration type organic wastewater treatment device according to claim 4, characterized in that: The catalyst layer of the cathode plate is composed of carbon-based material and polytetrafluoroethylene.

7. The internal aeration type organic wastewater treatment device according to claim 6, characterized in that: The thickness of the catalytic layer ranges from 0.1 to 10 mm.

8. The internal aeration type organic wastewater treatment device according to claim 1, characterized in that: The aperture of the aeration device is nanometer or micrometer.

9. An internal aeration organic wastewater treatment method, characterized in that: The method is implemented based on the internal aeration type organic wastewater treatment device according to any one of claims 1 to 8, and comprises the following steps: (1) passing organic wastewater into an electrolytic cell; (2) introducing air into the electrolytic cell through an aeration device so that the anode region where the anode plate in the electrolytic cell is located absorbs oxygen; (3) introducing air into the cathode plate of the electrolytic cell through an air pump; (4) supplying power to the electrolytic cell through a DC power supply to activate the oxygen in the anode region and generate hydrogen peroxide in the cathode region where the cathode plate is located; (5) The organic wastewater treated in steps (1) to (4) is discharged through the outlet pipe in the electrolytic cell.

10. The internal aeration organic wastewater treatment method according to claim 9, characterized in that: In step (3), after air is introduced into the cathode plate of the electrolytic cell through an air pump, the air-water ratio inside the cathode plate is between 5:1 and 30:1.

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