Three-dimensional coupling electro-catalytic oxidation sewage treatment process

Abstract

The application discloses a three-dimensional coupling electro-catalytic oxidation sewage treatment process and belongs to the sewage treatment field. The process flow comprises the following steps: 1. filtration; 2. ozone-hydrogen peroxide-ultraviolet light three-dimensional coupling treatment; 3. electrolysis pretreatment; and 4. electrochemical electro-catalytic oxidation treatment. The technical advantages of the application mainly result from the electrode plate discharge and ion filler common discharge, so that the technical effects of high oxidation efficiency, wide adaptation range, controllable operation cost and long-term stability are achieved.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment, specifically a three-dimensional coupled electrocatalytic oxidation wastewater treatment process. Background Technology

[0002] With industrialization, manufacturing generates large amounts of wastewater, and the types and concentrations of recalcitrant organic compounds in this wastewater are also increasing. Traditional wastewater treatment technologies are unable to achieve ideal results in this situation.

[0003] Electrochemical catalytic oxidation is a promising process for effectively removing recalcitrant compounds. Traditional two-dimensional electrolysis processes are limited to the interface between the electrode plate and the liquid, restricting the reaction range and progress. Therefore, fully utilizing the advantages of electrocatalytic oxidation and maximizing its effectiveness in wastewater treatment is crucial. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to overcome the difficulties in degrading macromolecular pollutants in wastewater through electrochemical treatment, and to address the problem that the reaction process is limited to the interface between the electrode plate and the liquid surface. The invention provides a three-dimensional coupled electrocatalytic oxidation wastewater treatment process that enhances electrocatalytic oxidation through physicochemical pretreatment and optimization of the electrolysis process, thereby achieving the goal of highly efficient degradation of pollutants in wastewater.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] This application provides a three-dimensional coupled electrocatalytic oxidation treatment process, which aims to improve the ability of electrocatalytic treatment of wastewater. The specific process flow is as follows:

[0007] S1. Remove insoluble particulate matter, suspended solids and floating matter from wastewater using physical methods, and discharge liquid 1;

[0008] S2. Introduce ozone and hydrogen peroxide into liquid 1, and simultaneously irradiate the surface of liquid 1 with ultraviolet light, then discharge liquid 2;

[0009] S3. Adjust the pH, temperature and conductivity of liquid 2 to obtain liquid 3;

[0010] S4. Add liquid 3 to the electrolytic cell and electrolyze it with the ion packing material through the electrode plates to obtain the treated wastewater.

[0011] Furthermore, the physical method in S1 is either sieving or sedimentation.

[0012] Furthermore, the mass ratio of ozone to COD in S2 is (1.0-3.0):1; the molar ratio of H2O2 to ozone is (0.5-2.0):1; and the ultraviolet irradiation conditions are wavelength 230-280nm, power density 10-50W / m, and irradiation time 15-30min.

[0013] The main functions of ozone in the system are: 1. Strong oxidative decomposition of organic matter, directly destroying the structures of benzene rings, double bonds, and heterocycles, transforming large, difficult-to-degrade organic molecules into small, easily degradable compounds. 2. Rapid decolorization, decolorizing industrial wastewater by destroying chromophores. 3. Sterilization and disinfection, killing bacteria, viruses, algae, and other organisms, replacing traditional chlorine-based sterilization methods, and eliminating secondary pollution from residual chlorine.

[0014] The optimal mass ratio of ozone to COD is (1.0-3.0):1. When the ratio is too low, pollutants cannot be fully decomposed. When the amount added is too large, in addition to wasting reagents, the following results will occur: 1. Continuous flushing with high concentrations of ozone accelerates the aging of carbon nanotubes; 2. It is easy to produce toxic byproducts such as aldehydes, which affect the treatment effect; 3. Excessive ozone will inhibit the generation of hydroxyl radicals, affecting the wastewater treatment effect.

[0015] The role of hydrogen peroxide in the system is manifested in: 1. Strong oxidation, which destroys compounds with aromatic structures such as benzene rings and heterocycles by producing hydroxyl radicals; 2. Decolorization, which decolorizes industrial wastewater by destroying chromophores; 3. Reaction with reducing pollutants, which undergoes redox reactions with compounds such as hydrogen sulfide, thiols, nitrites, and ferrous ions; 4. Synergistic effect with ozone and ultraviolet light, which greatly improves oxidation efficiency and reduces the amount of reagents used.

[0016] The optimal molar ratio of hydrogen peroxide to ozone is (0.5-2.0):1. A ratio that is too low will not fully exert its synergistic effect, affecting the degradation of pollutants; a ratio that is too high will cause the following results: 1. Excess hydrogen peroxide cannot be decomposed in time, indirectly increasing the COD of the water; 2. Excess hydrogen peroxide will damage the surface sites of the catalyst, causing catalyst deactivation and shortening its service life; 3. The water's oxidizing power is too strong, easily generating small-molecule organic acids and other products; 4. Corrosion of equipment.

[0017] The role of ultraviolet light in the system is manifested in: 1. sterilization and disinfection, destroying the nucleic acid structure of bacteria and viruses, and inactivating bacteria and parasite eggs; 2. wastewater decolorization, destroying conjugated chromophores, and assisting in the removal of water color; 3. removal of residual oxidants, decomposing residual hydrogen peroxide and ozone, and avoiding affecting subsequent treatment processes.

[0018] The irradiation conditions for ultraviolet light are a wavelength of 230-280 nm, a power density of 10-50 W / m, and an irradiation time of 15-30 min. Insufficient intensity will reduce the treatment results. Excessive intensity will lead to the following consequences: 1. Increased energy consumption and accelerated equipment aging; 2. Increased side reactions under strong ultraviolet light irradiation, affecting the treatment effect; 3. Accelerated over-mineralization of organic matter in the water, resulting in a deterioration of the water body's balance.

[0019] The purpose of the synergistic effect of these three components in the system is to directly generate hydroxyl radicals through ultraviolet light-induced hydrogen peroxide decomposition, while simultaneously activating ozone to generate both hydroxyl and oxygen radicals, thereby increasing the efficiency of free radical generation. Ozone and hydrogen peroxide undergo a liquid-phase chain reaction, significantly amplifying the free radical yield. The final effect is a 2-3 fold increase in the oxidation efficiency of a single oxidant, with a substantial reduction in dosage and energy consumption.

[0020] Furthermore, in S3, the pH of liquid 2 needs to be adjusted to 6.5-7.5; the temperature needs to be adjusted to 15-35℃; and the conductivity needs to be adjusted to 1500-5000μS / cm.

[0021] When the conductivity of wastewater is between 1500 and 5000 μS / cm, the conditions required for electrolytic processes such as electrocatalytic oxidation, electrocoagulation, and electrolytic ammonia nitrogen removal can be met. When the conductivity is below 1500 μS / cm, the water resistance is high, the current is small under the same voltage, the electrode plates heat up severely, the electrolytic reaction is weak, and the current efficiency is low. When the conductivity is above 5000 μS / cm, the ion concentration is high, leading to a surge in side reactions (hydrogen evolution, oxygen evolution, chlorine evolution); ineffective power consumption increases, resulting in serious energy waste; the electrode plates are prone to scaling and passivation, accelerating electrode plate corrosion.

[0022] The pH value is chosen during the reaction to protect the electrode plates; excessive acidity or alkalinity will accelerate the corrosion of the electrode plates.

[0023] Furthermore, the S4 electrolysis uses a DC power supply with a current density of 20-80 mA / cm². 2 The voltage is 4-8V.

[0024] Direct current (DC) is used as the power source during electrolysis. Due to its simple structure, low cost, and stable operation, it is suitable for most wastewater treatment applications. Pulse electricity has low energy consumption and high current efficiency, making it suitable for treating high-concentration organic wastewater or wastewater containing large amounts of recalcitrant organic matter; however, its equipment and operating costs are high. The addition of ozone, hydrogen peroxide, and ultraviolet light during the treatment process decomposes recalcitrant organic matter into readily degradable organic matter, while also directly decomposing some readily degradable organic matter, thus reducing the electrolysis load. The addition of ion-filled materials during electrolysis improves current efficiency and reduces energy consumption, compensating for the shortcomings of DC compared to pulse electricity in wastewater treatment.

[0025] During electrolysis, if the current density and voltage are too low, the electrolysis reaction will be weak; if the current density and voltage are too high, the side reactions will increase, leading to more energy waste.

[0026] Furthermore, the anode material is titanium plated with ruthenium-iridium, the cathode is stainless steel or titanium alloy, and the electrode spacing is controlled at 10-25cm.

[0027] Titanium-plated ruthenium-iridium is chosen as the anode electrode because of its low chlorine evolution potential, resistance to salt corrosion, and good conductivity, which makes it suitable for conventional electrocatalytic engineering. Stainless steel or titanium alloy is chosen as the cathode because both are cost-effective, resistant to salt and alkali, not easily corroded, and not prone to excessive hydrogen evolution.

[0028] The smaller the distance between the plates, the lower the resistance and the lower the energy consumption; if the distance is too small, it is easy to short circuit and scale to stick together.

[0029] This electrode design can withstand corrosion from high concentrations of inorganic salt ions, avoiding the impact of electrode wear on treatment efficiency. The electrocatalytic sites on the anode surface generate a large number of hydroxyl radicals. These radicals are non-selective and can attack the molecular chains of recalcitrant organic pollutants in wastewater, opening their rings and decomposing them into easily degradable small-molecule organic matter, CO2, or H2O, thus reducing COD load. In addition to the oxidation effect of the anode, a reduction reaction of heavy metal ions can simultaneously occur on the cathode surface, causing heavy metal ions to accumulate and deposit on the cathode surface, or to be converted into non-toxic, low-valence ions, achieving a synergistic effect of organic pollutant degradation and toxic heavy metal removal.

[0030] Furthermore, the ion packing material is any one of supported manganese-based or supported iron-based catalysts, and the dosage of the ion packing material is 0.5-5.0 g / L. The manganese-based catalyst support is acidified multi-walled carbon nanotubes with a diameter of 20-40 nm, and the active component is any one or more of α-MnO2, δ-MnO2 and Mn2O3, with a manganese element mass fraction of 5%-8%. In the iron-based catalyst, the acidified multi-walled carbon nanotubes have a diameter of 20-40 nm, and the active component is one or more of α-Fe2O3, γ-Fe2O3 and Fe3O4, with an iron element loading of 4%-8%.

[0031] Ion-based fillers are used to pack catalytic materials between the main electrode plates. Through metal multivalent cycling, surface oxygen vacancies, and metal-support synergy, the degradation and decolorization of recalcitrant organic matter can be achieved.

[0032] Carbon nanotubes possess high conductivity, large specific area, excellent electrochemical stability, and superior mass transfer performance. As a filler, they can optimize the conductive pathways of the system, reducing energy consumption, and effectively improve the efficiency of wastewater electrolysis treatment by enriching pollutants and enhancing electrolytic oxidation reactions. Compared to activated carbon, they have stronger conductivity, more stable structure, and faster electron transfer; compared to ceramsite / zeolite, their conductivity is far superior, as ceramsite / zeolite has no conductivity; compared to graphite particles, their tube-like structure is more conducive to mass transfer, has better dispersibility, and lower filling resistance.

[0033] While carbon nanotubes with a diameter of less than 20 nm exhibit the best electrical conductivity, they suffer from low mechanical strength, structural instability, and susceptibility to deformation, making them unsuitable for engineering applications. Multi-walled nanotubes are significantly cheaper than single-walled ones, making them suitable for large-scale engineering procurement.

[0034] The purpose of acidification of carbon nanotubes is: 1. to improve surface hydrophilicity and wettability in aqueous solutions; 2. to provide anchor points for metal ions, improve load stability, and reduce metal dissolution; 3. to optimize electron transfer efficiency.

[0035] Supported manganese-based catalysts are selected because manganese has abundant oxygen vacancies and multiple valence states, giving it excellent catalytic activity at room temperature and advantages in treating recalcitrant organic compounds and ring-opening compounds.

[0036] Supported iron-based catalysts are selected because they are inexpensive, green and non-toxic, have stable redox cycles, and are suitable for most water treatment processes.

[0037] When the metal loading on carbon nanotubes is too low, the catalytic activity will be weak and the degradation rate will be low; when the loading is too high, it will lead to: 1. Aggregation of active components, resulting in reduced effective utilization; 2. Blockage of carbon nanotube channels, affecting mass transfer; 3. Increased dissolution of metal ions, which may lead to excessive heavy metals in the effluent; 4. Damage to the conductive network of CNTs, resulting in increased electrolysis energy consumption.

[0038] Furthermore, the hydraulic residence time is 60-180 minutes.

[0039] If the hydraulic residence time is too short, pollutants will not be decomposed sufficiently; if it is too long, side reactions will increase and energy consumption will intensify.

[0040] Beneficial technical effects:

[0041] This application provides a three-dimensional coupled wastewater treatment process that integrates three core technologies: electrochemical oxidation, electrocatalytic oxidation, and multiphase coupling. It breaks through the limitations of traditional two-dimensional electrolytic reactions, achieving synergistic effects of multiple technologies. Specifically developed for complex industrial wastewater with high salinity, high COD, poor biodegradability, and low biodegradability, this technology is ideal for treating recalcitrant organic wastewater. The core of this technology involves ultraviolet light-induced hydrogen peroxide direct pyrolysis to generate hydroxyl radicals, while simultaneously activating ozone to produce hydroxyl and oxygen radicals, accelerating radical generation efficiency. The liquid-phase chain reaction between ozone and hydrogen peroxide amplifies radical production exponentially. The final effect is a 2-3 fold increase in the oxidation efficiency of a single oxidant, with a significant reduction in reagent and energy consumption. Ozone-hydrogen peroxide-ultraviolet light pretreatment degrades recalcitrant organic matter in wastewater into easily degradable small molecule compounds, which are then directly decomposed, reducing the electrolysis load. An external DC electric field forms a stable electrochemical system. The space between the electrode plates is filled with a specialized porous catalytic packing material. Under the influence of the external DC electric field, the catalytic packing particles are polarized and charged, forming numerous micro-electrolysis units, thus creating a three-dimensional electrochemical reaction system. Within the electrolysis system, on the one hand, organic pollutants in wastewater are directly degraded and heavy metal ions are removed through electrochemical oxidation-reduction reactions. On the other hand, the multiphase catalytic properties of the ion packing material stimulate the generation of a large number of highly oxidizing hydroxyl radicals within the system, enhancing the electrocatalytic oxidation reaction and rapidly mineralizing recalcitrant organic matter. Simultaneously, relying on multiphase coupling, electrochemical, electrocatalytic oxidation, and adsorption-sedimentation reaction mechanisms work synergistically, eliminating the need for large amounts of additional oxidants to efficiently decompose stubborn organic pollutants in wastewater and simultaneously reduce and remove heavy metal ions, ultimately achieving wastewater quality purification that meets standards. Attached Figure Description

[0042] Figure 1 This is a flow chart of a three-dimensional coupled electrocatalytic oxidation wastewater treatment process. Detailed Implementation

[0043] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof.

[0044] Example 1

[0045] One such Figure 1 The three-dimensional coupled electrocatalytic oxidation wastewater treatment process shown includes the following steps:

[0046] 1. Wastewater is treated by sedimentation to remove insoluble pollutants, resulting in liquid 1.

[0047] 2. Introduce ozone and hydrogen peroxide into liquid 1, and simultaneously irradiate the liquid surface with ultraviolet light, then discharge liquid 2. The mass ratio of ozone to COD is 1.0:1; the molar ratio of hydrogen peroxide to ozone is 0.5:1; the ultraviolet light irradiation conditions are: wavelength 230nm, power density 10W / m, and irradiation time 15min.

[0048] 3. Adjust the pH of liquid 2 to 6.5; adjust the temperature to 25℃; adjust the conductivity to 1500μS / cm.

[0049] 4. Electrolysis is performed in an electrolytic cell using a DC power supply with a current density of 20 mA / cm³. 2 The voltage is 4V; the anode material is titanium plated with ruthenium and iridium, the cathode is stainless steel, and the electrode spacing is controlled at 10cm; the ion packing material is a supported manganese-based ion packing material with a dosage of 0.5g / L; the manganese-based catalyst support is acidified multi-walled carbon nanotubes with a diameter of 20nm; the active component is α-MnO2 with a manganese element mass fraction of 5%; the hydraulic retention time is 60 minutes.

[0050] Example 2

[0051] One such Figure 1 The three-dimensional coupled electrocatalytic oxidation wastewater treatment process shown includes the following steps:

[0052] 1. Wastewater is treated by sedimentation to remove insoluble pollutants, resulting in liquid 1.

[0053] 2. Introduce ozone and hydrogen peroxide into liquid 1, and simultaneously irradiate the liquid surface with ultraviolet light, then discharge liquid 2. The mass ratio of ozone to COD is 3.0:1; the molar ratio of hydrogen peroxide to ozone is 2.0:1; the ultraviolet irradiation conditions are: wavelength 280nm, power density 50W / m, and irradiation time 30min.

[0054] 3. Adjust the pH of liquid 2 to 7.5; adjust the temperature to 25℃; adjust the conductivity to 5000μS / cm.

[0055] 4. Electrolysis is performed in an electrolytic cell using a DC power supply with a current density of 80 mA / cm³. 2 The voltage is 8V; the anode material is titanium plated with ruthenium and iridium, the cathode is titanium alloy, and the electrode spacing is controlled at 25cm; the ion packing material is a supported manganese-based ion packing material with a packing amount of 5.0g / L; the manganese-based catalyst support is acidified multi-walled carbon nanotubes with a diameter of 40nm; the active component is Mn2O3 with a manganese element mass fraction of 8%; the hydraulic retention time is 180 minutes.

[0056] Example 3

[0057] One such Figure 1 The three-dimensional coupled electrocatalytic oxidation wastewater treatment process shown includes the following steps:

[0058] 1. Wastewater is treated by sedimentation to remove insoluble pollutants, resulting in liquid 1.

[0059] 2. Introduce ozone and hydrogen peroxide into liquid 1, and simultaneously irradiate the liquid surface with ultraviolet light, then discharge liquid 2. The mass ratio of ozone to COD is 2.0:1; the molar ratio of hydrogen peroxide to ozone is 1.0:1; the ultraviolet light irradiation conditions are: wavelength 254nm, power density 20W / m, and irradiation time 20min.

[0060] 3. Adjust the pH of liquid 2 to 7.5; adjust the temperature to 25℃; adjust the conductivity to 2000μS / cm.

[0061] 4. Electrolysis is performed in an electrolytic cell using a DC power supply with a current density of 30 mA / cm³. 2 The voltage is 5V; the anode material is titanium plated with ruthenium and iridium, the cathode is stainless steel, and the electrode spacing is controlled at 15cm; the ion packing material is a supported iron-based ion packing material with a dosage of 2.0g / L, a tube diameter of 25nm, an active component of α-Fe2O3, and an iron element loading of 5%; the hydraulic retention time is 100 minutes.

[0062] Example 4

[0063] One such Figure 1 The three-dimensional coupled electrocatalytic oxidation wastewater treatment process shown includes the following steps:

[0064] 1. Wastewater is treated by sedimentation to remove insoluble pollutants, resulting in liquid 1.

[0065] 2. Introduce ozone and hydrogen peroxide into liquid 1, and simultaneously irradiate the liquid surface with ultraviolet light, then discharge liquid 2. The mass ratio of ozone to COD is 2.5:1; the molar ratio of hydrogen peroxide to ozone is 1.2:1; the ultraviolet light irradiation conditions are: wavelength 265nm, power density 25W / m, and irradiation time 25min.

[0066] 3. Adjust the pH of liquid 2 to 7.5; adjust the temperature to 25℃; adjust the conductivity to 4000μS / cm.

[0067] 4. Electrolysis is performed in an electrolytic cell using a DC power supply with a current density of 50 mA / cm³. 2 The voltage is 6V; the anode material is titanium plated with ruthenium and iridium, the cathode is stainless steel, and the electrode spacing is controlled at 20cm; the ion packing material is a supported iron-based ion packing material with a dosage of 4.0g / L, a tube diameter of 30nm, an active component of Fe3O4, and an iron element loading of 6%; the hydraulic retention time is 150 minutes.

[0068] Comparative Example 1

[0069] This comparative example provides a three-dimensional coupled electrocatalytic oxidation wastewater treatment process. The difference between this comparative example and Example 3 is that this comparative example does not include ozone-hydrogen peroxide-ultraviolet light treatment. Other process parameters and operating steps are exactly the same as in Example 3.

[0070] Comparative Example 2

[0071] This comparative example provides a three-dimensional coupled electrocatalytic oxidation wastewater treatment process. The difference between this comparative example and Example 3 is that this comparative example does not use ion packing material, but the other process parameters and operating steps are exactly the same as those in Example 3.

[0072] Comparative Example 3

[0073] This comparative example provides a three-dimensional coupled electrocatalytic oxidation wastewater treatment process. The difference between this comparative example and Example 3 is that this comparative example does not include ozone-hydrogen peroxide-ultraviolet light treatment and ion packing material. Other process parameters and operating steps are exactly the same as in Example 3.

[0074] The wastewater treatment effects of Examples 1-4 and Comparative Examples 1-3 were tested, and the results are shown in Table 1.

[0075] Table 1 Wastewater Treatment Results Test

[0076]

[0077] The study of four examples and three comparative examples confirms that the ozone-hydrogen peroxide-ultraviolet light three-dimensional coupling and particle electrode packing method of this application significantly improves the performance of electrochemical oxidation treatment of wastewater.

[0078] The high removal rates of COD and TOC exceeding 85% in Examples 1-4 are attributed to the three-dimensional coupling treatment of ozone, hydrogen peroxide, and ultraviolet light. This step ensures the thorough oxidative decomposition of small molecules in the wastewater, further removing residual pollutants during electrolysis. The high removal rate of ammonia nitrogen exceeding 80% is also attributed to this three-dimensional coupling treatment. This step oxidizes ammonia nitrogen in the wastewater into nitro and nitrosyl groups, which are then reduced to nitrogen gas during electrolysis. The removal of phosphorus and other characteristic pollutants in the wastewater (over 85%) is achieved through the three-dimensional coupling treatment of ozone, hydrogen peroxide, and ultraviolet light, which induces a redox reaction. The phosphorus and phosphorus combine and undergo a mineralization reaction. Enhanced reaction conditions during electrolysis further mineralize these pollutants, resulting in effective removal.

[0079] The core of this process is: 1. In the three-dimensional coupling treatment of ozone-hydrogen peroxide-ultraviolet light, ultraviolet light excites hydrogen peroxide to directly decompose and generate hydroxyl radicals, while simultaneously activating ozone to produce hydroxyl and oxygen radicals, accelerating the efficiency of radical generation; the liquid-phase chain reaction of ozone and hydrogen peroxide amplifies the radical production many times over, and the final effect is reflected in a 2-3 times increase in the oxidation efficiency of a single oxidant, with a significant reduction in reagent and energy consumption; it degrades recalcitrant organic matter in wastewater into easily degradable small molecule compounds, which are then directly decomposed, reducing the electrolysis load. 2. Particle electrode packing: a special catalytic packing material filled between the main electrode plates. Through metal multi-valence state cycling, surface oxygen vacancies, and metal-support synergy, the degradation and decolorization of recalcitrant organic matter can be achieved. Carbon nanotubes, due to their excellent conductivity, can accelerate electron transfer between metal ions and accelerate the redox cycle; at the same time, a strong interaction is formed between the support surface and metal species, inhibiting the dissolution of metal ions and improving the stability and cycle life of the catalyst. The micro-electric field formed by the porous structure of the packing can promote the uniform distribution of wastewater in the gaps between the packing layers, accelerate the directional migration of pollutant molecules to the electrode surface, and further improve the mass transfer effect of the micro-electrolysis reaction unit.

[0080] In Comparative Example 1, the absence of ozone-hydrogen peroxide-ultraviolet three-dimensional coupled treatment prevented some recalcitrant macromolecular compounds from being converted into smaller, more readily degradable compounds. This increased the COD content during electrolysis, reducing the wastewater treatment efficiency. Furthermore, ammonia nitrogen could not be oxidized to nitrates and nitrosamines, further lowering the ammonia nitrogen removal rate. Phosphorus and other characteristic pollutants lacked a mineralization step; the mineralization process relied solely on electrolysis, resulting in reduced removal rates for both. All pollutant removal indicators differed by 20-30% compared to the example.

[0081] In Comparative Example 2, the absence of particle electrode packing limited the electrolysis reaction to the contact surface between the wastewater and the electrode, resulting in a smaller reaction range and reduced removal rates of COD, TOC, total phosphorus, and characteristic pollutants. Furthermore, the lack of three-dimensional electrode packing reduced the reaction range during the reduction of nitro and nitrosyl groups to nitrogen gas, and the absence of a catalyst further decreased reaction efficiency. All pollutant removal indicators were 20-30% lower than in the Example 2.

[0082] Comparative Example 3, lacking the ozone-hydrogen peroxide-ultraviolet three-dimensional coupling treatment and particle electrode packing, only involved a simple two-dimensional electrolysis reaction. The reaction effect was the worst among all cases, fully demonstrating the importance of the ozone-hydrogen peroxide-ultraviolet three-dimensional coupling treatment and particle electrode packing for this process. All pollutant removal indicators were 30-50% lower than in the examples, making it the worst treatment among all examples.

[0083] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A three-dimensional coupled electrocatalytic oxidation wastewater treatment process, characterized in that, The specific process flow is as follows: S1. Remove insoluble particulate matter, suspended solids and floating matter from wastewater using physical methods, and discharge liquid 1; S2. Introduce ozone and hydrogen peroxide into liquid 1, and simultaneously irradiate the surface of liquid 1 with ultraviolet light, then discharge liquid 2; S3. Adjust the pH, temperature and conductivity of liquid 2 to obtain liquid 3; S4. Add liquid 3 to the electrolytic cell and electrolyze it with the ion packing material through the electrode plates to obtain the treated wastewater.

2. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 1, characterized in that, The physical method described in S1 includes either sieving or sedimentation.

3. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 1, characterized in that, The mass ratio of ozone in S2 to COD in liquid 1 is (1.0-3.0):1; the molar ratio of H2O2 to ozone is (0.5-2.0):1; the ultraviolet irradiation conditions are a wavelength of 230-280nm, a power density of 10-50W / m, and an irradiation time of 15-30min.

4. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 1, characterized in that, In S3, the pH of liquid 2 is adjusted to 6.5-7.5; the temperature is adjusted to 15-35℃; and the conductivity is adjusted to 1500-5000μS / cm.

5. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 1, characterized in that, When liquid 3 in S4 is electrolyzed, a DC power supply is used with a current density of 20-80 mA / cm³. 2 The voltage is 4-8V.

6. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 1, characterized in that, In S4, the anode material of the electrode plate is titanium plated with ruthenium and iridium, and the cathode material includes any one of stainless steel or titanium alloy; the ion packing material includes any one of supported manganese-based catalyst or supported iron-based catalyst.

7. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 1, characterized in that, The hydraulic residence time of liquid 3 in S4 is 60-180 min.

8. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 1, characterized in that, The spacing between the electrode plates in S4 is controlled at 10-25cm; the amount of ion packing material added is 0.5-5.0g / L.

9. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 6, characterized in that, The supported manganese-based catalyst is supported by acidified multi-walled carbon nanotubes with a diameter of 20-40 nm; the active component of the supported manganese-based catalyst includes any one or more of α-MnO2, δ-MnO2, and Mn2O3; the supported iron-based catalyst is supported by acidified multi-walled carbon nanotubes with a diameter of 20-40 nm; the active component of the supported iron-based catalyst includes one or more of α-Fe2O3, γ-Fe2O3, and Fe3O4.

10. The three-dimensional coupled electrocatalytic oxidation wastewater treatment process as described in claim 9, characterized in that, In the supported manganese-based catalyst, the loading of manganese is 5%-8%; in the supported iron-based catalyst, the loading of iron is 4%-8%.

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