A hydrogen peroxide generating device for ex-situ soil remediation and a soil remediation method

Abstract

The application discloses a hydrogen peroxide generating device for ex-situ soil remediation and a soil remediation method, and belongs to the technical field of soil remediation. The hydrogen peroxide generating device comprises a reaction stack and a liquid inlet tank. The reaction stack is connected with the liquid inlet tank. The reaction stack comprises end plates, anode plates, anode electrodes, anode flow channel plates, diaphragms, cathode plates, cathode electrodes, gas plates, cathode electrodes, cathode plate symmetry plates, diaphragms, anode flow channel plate symmetry plates, anode electrodes, anode double-sided plates, anode flow channel plates, diaphragms, cathode plates, cathode electrodes, gas plates, cathode electrodes, cathode plate symmetry plates, diaphragms, anode flow channel plate symmetry plates, anode electrodes, anode plate symmetry plates and end plate symmetry plates, which are stacked in sequence. The hydrogen peroxide generating device has excellent stability, can accurately adjust the effluent concentration of hydrogen peroxide according to the specific requirements of soil remediation, ensures the remediation effect, and is simple to operate and has significantly improved efficiency.

Description

Technical Field

[0001] This invention belongs to the field of soil remediation technology, and specifically relates to a hydrogen peroxide generator and a soil remediation method for ex-situ soil remediation. Background Technology

[0002] The widespread use of petroleum has posed a threat to soil ecosystems, making remediation technologies for petroleum-contaminated soils an urgent need, and various remediation technologies have been developed. Representative technologies include catalytic oxidation degradation methods such as Fenton's reagent, Fenton-like reactions, and persulfate. The core of these methods lies in using catalysts to rapidly generate a large number of highly reactive free radicals from oxidants. These highly oxidizing free radicals can oxidize organic pollutants to a mineralized state, achieving the soil remediation goal. In the aforementioned chemical remediation technologies, one of the key chemical reagents is hydrogen peroxide (H2O2). However, traditional chemical companies typically use the anthraquinone process to produce hydrogen peroxide. Due to technological limitations, the produced hydrogen peroxide needs to be purified and concentrated before it can be sold. This restricts its storage, transportation, sales radius, and production site, making it significantly affected by the surrounding industrial environment. Currently, because commercially available industrial-grade hydrogen peroxide reagents typically have a concentration exceeding 30%, they are typical regulated hazardous chemicals, posing significant safety challenges in procurement, transportation, and storage. Therefore, new methods for producing hydrogen peroxide solutions are urgently needed, and electrocatalytic production technology is a promising option. Significant progress has been made in the field of electrocatalytic hydrogen peroxide production. For example, Chinese patent (publication number CN217676934U) discloses an electrocatalytic high-efficiency hydrogen peroxide production electrode and integrated device. The electrode has a spherical structure, with a gas diffusion layer, a stainless steel mesh, and a catalyst layer arranged sequentially from the outside to the inside, and a support layer fixed on the outer edge of the stainless steel mesh. The gas diffusion layer is a waterproof and breathable nanofiber coating applied to the outside of the stainless steel mesh. The catalyst layer is attached to the inner surface of the stainless steel mesh by hot pressing. Chinese patent (CN217418827U) discloses a photoelectrocatalytic high-efficiency H2O2 production electrode and device, including a gas diffusion electrode, an upper connector, and a lower connector. The gas diffusion electrode is cylindrical, with its two ends connected by the upper and lower connectors. The upper and lower connectors are connected by multiple symmetrically arranged double-ended bolts located around the gas diffusion electrode. The gas diffusion electrode includes a cylindrical stainless steel mesh, with a gas diffusion layer on the inner side and a catalyst layer on the outer side.

[0003] In summary, although existing technologies have yielded significant research results regarding soil remediation and hydrogen peroxide production, improving the efficiency of hydrogen peroxide preparation to some extent, the overall production rate remains low. Furthermore, the concentration of hydrogen peroxide is difficult to adjust, resulting in limited practicality and hindering rapid and large-scale production in remote areas. Therefore, there is an urgent need to develop a new hydrogen peroxide production device. Summary of the Invention

[0004] To address the above problems, this invention discloses a hydrogen peroxide generating device for ex-situ soil remediation, comprising: a reactor and an inlet tank;

[0005] The reactor is connected to the liquid inlet tank;

[0006] The reactor comprises, in sequence, end plates, anode plates, anode electrodes, anode flow channel plates, diaphragms, cathode plates, cathode electrodes, gas plates, cathode electrodes, cathode plate symmetry plates, diaphragms, anode flow channel plate symmetry plates, anode electrodes, anode double-sided plates, anode flow channel plates, diaphragms, cathode plates, cathode electrodes, gas plates, cathode electrodes, cathode plate symmetry plates, diaphragms, anode flow channel plate symmetry plates, anode electrodes, anode plate symmetry plates, and end plate symmetry plates.

[0007] Furthermore, it also includes: inlet water pipe, outlet water pipe, spraying equipment, spray pipe and outlet tank;

[0008] The liquid inlet tank is connected to the reactor via a liquid inlet water pipe;

[0009] The reactor is connected to the liquid outlet tank via a liquid outlet pipe;

[0010] The liquid outlet tank is connected to the spraying equipment via a spray pipe.

[0011] Furthermore, it also includes: solar panels, solar controllers, and batteries;

[0012] The solar panel is connected to the solar controller;

[0013] The solar controller is connected to the battery;

[0014] The solar controller is connected to the reactor.

[0015] Furthermore, the membrane includes a proton exchange membrane, a cation exchange membrane, and an anion exchange membrane.

[0016] Furthermore, the anode electrode comprises a ruthenium-iridium titanium plate and an iron-nickel doped foam nickel plate.

[0017] Furthermore, the thickness of the ruthenium-iridium titanium plate ranges from 0.5 to 2 mm;

[0018] The ruthenium loading in the ruthenium-iridium-titanium plate is 6-8 g / m³. 2 The iridium loading is 2-4 g / m 2 .

[0019] Furthermore, the method for preparing the ruthenium-iridium-titanium plate is as follows:

[0020] The titanium sheet undergoes surface polishing.

[0021] The titanium sheet was alkali-washed for 1-3 hours using a sodium hydroxide solution with a mass concentration of 4-8%.

[0022] After alkaline washing, the titanium sheet is placed in an oxalic acid solution with a mass concentration of 4-8% for acid etching for 1-3 hours, then rinsed with water and dried.

[0023] Ruthenium oxide and iridium oxide are dissolved in a mixed solution of isobutanol, isopropanol and concentrated hydrochloric acid, and then sprayed onto a dried titanium sheet by ultrasonic spraying. The sheet is then dried at 60-85°C and thermally decomposed at 400-500°C. This process is repeated multiple times to obtain an oxide coating on the surface of the titanium sheet.

[0024] The titanium sheet with an oxide coating is cooled to room temperature to obtain the anode electrode.

[0025] Furthermore, the volume ratio of isobutanol, isopropanol, and concentrated hydrochloric acid is 2-3:2-3:1.

[0026] Furthermore, the cathode electrode uses carbon paper as a substrate and carbon-based materials as catalysts; wherein, the carbon-based materials include carbon black and modified carbon black;

[0027] The carbon paper has a thickness of 0.1-0.5 mm and a resistivity of <7 mΩ·cm;

[0028] The loading of carbon-based materials is 20-50 g / m³. 2 .

[0029] Furthermore, the method for preparing the cathode electrode is as follows:

[0030] The carbon-based material was etched in concentrated nitric acid at 70-90℃ for 8-48 hours. After cooling, it was washed with deionized water and anhydrous ethanol, then centrifuged and dried at 70-90℃ to obtain O-sp carbon black.

[0031] Anhydrous ethanol, distilled water and polytetrafluoroethylene coating are mixed evenly in a volume ratio of 2:1:0.05. Then O-sp carbon black is added, stirred and ultrasonically mixed evenly, and then ultrasonically sprayed onto both sides of an 80-120 mesh copper mesh until the copper mesh is completely covered.

[0032] The cathode electrode is obtained by hot pressing copper mesh and carbon paper at 70-90℃.

[0033] Furthermore, the reactor operates at a voltage of 1.5V-5V.

[0034] Furthermore, the electrolyte in the reactor is a sodium sulfate solution;

[0035] The flow rate of the electrolyte is 5–30 mL / min.

[0036] Furthermore, the gas in the reactor is air or oxygen;

[0037] The gas flow rate is 400–1000 mL / min.

[0038] This invention also discloses a soil remediation method based on the above-mentioned hydrogen peroxide generator for ex-situ soil remediation, comprising the following steps:

[0039] Hydrogen peroxide was prepared using a hydrogen peroxide generator and used for pretreatment of contaminated soil.

[0040] Add a reducing agent to the contaminated soil and stir it evenly. During the stirring process, add a certain amount of water to the contaminated soil and set a reduction time.

[0041] Ferrous sulfate was added to hydrogen peroxide in a certain proportion, and the hydrogen peroxide was sprayed onto the contaminated soil for an oxidation treatment time.

[0042] Furthermore, the concentration of the hydrogen peroxide is 0.1-3%.

[0043] Furthermore, the reducing agent is 1-3% of the mass of the contaminated soil;

[0044] The hydrogen peroxide is 10-30% of the mass of the contaminated soil;

[0045] The ferrous sulfate content is 0.5-2% of the mass of hydrogen peroxide.

[0046] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0047] 1. This invention addresses the challenges of hydrogen peroxide supply in traditional soil remediation methods by proposing an innovative solution. This solution not only solves the problem of limited hydrogen peroxide transportation range but also significantly reduces safety risks during transportation. The device of this invention exhibits excellent stability and can precisely adjust the hydrogen peroxide concentration according to the specific needs of soil remediation, ensuring remediation effectiveness while being easy to operate and significantly improving efficiency.

[0048] 2. Low-concentration hydrogen peroxide is particularly critical in soil remediation. This invention reduces the process steps of diluting and mixing high-concentration hydrogen peroxide, thereby significantly reducing potential safety hazards during storage and mixing. In acidic or neutral environments, oxygen is reduced to hydrogen peroxide at the cathode through electrolysis, while water in the sodium sulfate solution at the anode is oxidized to generate oxygen. The operating cost of this hydrogen peroxide electrolysis system is closely related to electricity costs, and by equipping it with a solar power system, its operating cost is almost negligible when there is sufficient sunlight.

[0049] 3. The on-site production unit only requires sodium sulfate solution, electricity, and oxygen to achieve continuous production and immediate use without storage, thus avoiding the risk of supply interruption associated with traditional hydrogen peroxide. The hydrogen peroxide produced by this unit has a concentration of 0.1-3%, which is far below the national limit for easily explosive hazardous chemicals, thus requiring less stringent safety supervision. In contrast, the design and construction of tank areas and pipelines for storing 50% concentration hydrogen peroxide must comply with strict Class A design specifications, and the safety supervision department will conduct regular on-site inspections.

[0050] 4. Compared with the traditional anthraquinone method for producing hydrogen peroxide, the hydrogen peroxide electrolysis production device of this invention is a completely green technology, requiring only oxygen, electricity and sodium sulfate solution as raw materials, with no by-products generated. This invention aims to meet the needs of enterprises for "remediation, health and environmental safety", and has developed a green and efficient on-site hydrogen peroxide preparation device for ex-situ soil remediation to meet the actual needs of enterprises for low-cost risk control.

[0051] 5. Furthermore, the implementation of this invention not only improves the efficiency and safety of soil remediation but also significantly reduces environmental impact. The promotion and application of this invention will help drive the green transformation of the soil remediation industry and make a positive contribution to protecting the ecological environment. Through the application of this invention, enterprises can carry out soil remediation in a more environmentally friendly and economical way, while ensuring the safety and reliability of the remediation process, bringing long-term economic and social benefits to enterprises.

[0052] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 A schematic diagram of a hydrogen peroxide generator for ex-situ soil remediation according to an embodiment of the present invention is shown.

[0055] Figure 2 A schematic diagram of the reactor structure according to an embodiment of the present invention is shown;

[0056] Figure 3 A schematic diagram of the end plate according to an embodiment of the present invention is shown;

[0057] Figure 4 A schematic diagram of the structure of the double-sided anode panel according to an embodiment of the present invention is shown;

[0058] Figure 5 A schematic diagram of the structure of a gas plate according to an embodiment of the present invention is shown;

[0059] Figure 6 A schematic diagram of the structure of a cathode plate according to an embodiment of the present invention is shown;

[0060] Figure 7 A schematic diagram of the structure of an anode plate according to an embodiment of the present invention is shown.

[0061] Reference numerals: 1. Solar panel; 2. Reactor; 3. Solar controller; 4. Battery; 5. Inlet water pipe; 6. Outlet water pipe; 7. Spray pipe; 8. Inlet tank; 9. Outlet tank; 10. Soil mound; 11. End plate; 12. Anode plate; 13. Anode flow channel plate; 14. Cathode plate; 15. Gas plate; 16. Symmetrical cathode plate; 17. Symmetrical anode flow channel plate; 18. Double-sided anode plate; 19. Symmetrical anode plate; 20. Symmetrical end plate. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] like Figure 1 As shown, the present invention proposes a hydrogen peroxide generating device for ex-situ soil remediation, comprising: a reactor 2 and an inlet tank 8;

[0064] The reactor 2 is connected to the liquid inlet tank 8;

[0065] like Figure 2As shown, the reactor 2 comprises, in sequence, end plates 11, anode plates 12, anode electrodes, anode flow channel plates 13, diaphragms, cathode plates 14, cathode electrodes, gas plates 15, cathode electrodes, cathode plate symmetry plates 16, diaphragms, anode flow channel plate symmetry plates 17, anode electrodes, anode double-sided plates 18, anode flow channel plates 13, diaphragms, cathode plates 14, cathode electrodes, gas plates 15, cathode electrodes, cathode plate symmetry plates 16, diaphragms, anode flow channel plate symmetry plates 17, anode electrodes, anode plate symmetry plates 19, and end plate symmetry plates 20. The plates are separated by silicone gaskets to maintain airtightness. Each plate is provided with anode liquid flow holes, cathode liquid flow holes, and gas channels; the specific flow patterns of the liquid and gas are not described in detail here. Figure 1 The anode electrode, cathode electrode, and diaphragm are not shown.

[0066] Reactor 2 can also be cyclically stacked based on the following sequence: anode plate 12, anode electrode, anode flow channel plate 13, diaphragm, cathode plate 14, cathode electrode, gas plate 15, cathode electrode, cathode plate symmetry plate 16, diaphragm, anode flow channel plate symmetry plate 17, anode electrode, anode double-sided plate 18, anode flow channel plate 13, diaphragm, cathode plate 14, cathode electrode, gas plate 15, cathode electrode, cathode plate symmetry plate 16, diaphragm, anode flow channel plate symmetry plate 17, anode electrode, anode plate symmetry plate 19.

[0067] End plates 11, used for mechanical support, are located on both sides of the fuel cell stack to fix the fuel cell stack, withstand stacking pressure, and prevent short circuits. End plates 11 are insulated and connect to external pipes, such as oxygen ports.

[0068] Anode plate 12 is used to provide support for the anode electrode and to provide an anode electrolyte pool;

[0069] The anode electrode is used to initiate the anodic OER (oxygen evolution reaction).

[0070] The anode flow channel plate 13, together with the anode plate 12, provides support for the anode electrode and provides the anode electrolyte pool.

[0071] A diaphragm is used to separate the cathode cell from the anode cell for proton conduction.

[0072] The cathode plate 14 is used to provide support for the cathode electrode and to provide a cathode electrolyte pool;

[0073] The cathode electrode is used to carry out the core reaction of this device, the two-electron oxygen reduction reaction, which reduces oxygen to produce hydrogen peroxide.

[0074] Gas plate 15 is used to support one side of the cathode electrode and as an oxygen channel.

[0075] The cathode plate symmetry plate 16, which has the same function as the cathode plate 14, is located on the other side of the gas plate 15. The cathode electrode and the cathode plate symmetry plate 16 are located at both ends of the gas plate 15 and have the same function. This symmetrical assembly method can effectively improve oxygen utilization.

[0076] The anode flow channel plate symmetry plate 17 has the same function as the anode flow channel plate 13, except that this device adopts a symmetrical assembly method.

[0077] The double-sided anode panel 18 is used to support the anode electrode and serves as the anode electrolyte tank, with anode electrodes on both sides.

[0078] Reactor 2 is made of transparent acrylic and is a square with a side length ranging from 5 to 50 cm.

[0079] A proton exchange membrane separates the cathode and anode electrolytes between the cathode plate 14 and the anode flow channel plate 13, preventing the reactions at both electrodes from affecting each other. The cathode electrode uses carbon paper as a substrate and carbon-based material as a catalyst, coated by spraying. The cathode electrode is located between the cathode plate 14 and the gas plate 15, or between the cathode plate symmetrical plate 16 and the gas plate 15. The anode undergoes an oxygen evolution reaction. The material used can be nickel foam supported on iron, or precious metals such as ruthenium, iridium, and tantalum supported on a titanium sheet. It is located between the anode plate 12 and the anode flow channel plate 13, or between the anode flow channel plate symmetrical plate 17 and the anode plate symmetrical plate 19. The inner diameter of the pipe used is 1–10 mm; for example, the inner diameter is 5 mm.

[0080] This invention utilizes an electrocatalytic oxygen reduction method to produce hydrogen peroxide, which involves converting water, oxygen, and electricity from a sodium sulfate solution into hydrogen peroxide. The specific electrochemical reaction process is as follows:

[0081] Cathode reaction: O2 + 2H + +2e - →H2O2;

[0082] Anode reaction: 2H₂O → 1 / 2O₂ + 2H₂O + +2e - ;

[0083] Overall reaction: 1 / 2O2 + H2O → H2O2;

[0084] In this invention, the electrolyte is first stored in an inlet tank 8, and then enters the inlet water pipe 5 from the inlet tank 8. It then enters the electrocatalytic hydrogen peroxide reactor 2 for electrochemical reaction. Multiple electrocatalytic hydrogen peroxide reactors 2 can be connected in parallel or used individually, and the voltage can be flexibly adjusted according to requirements. The positive and negative electrode voltages of the electrocatalytic hydrogen peroxide reactor 2 are 1.5V-5V, or more specifically, 2V-4V. The inlet flow rate of the anode and cathode and the power supply voltage can be changed according to specific testing requirements to control the final hydrogen peroxide concentration. Gas enters the pipeline through a gas valve and a gas flow metering pump. The gas source can be ordinary air or oxygen. The electrolyte flow rate is between 5 and 30 mL / min, and the total gas flow rate is between 400 and 1000 mL / min. The gas and liquid enter the reactor 2 separately, thereby stably generating hydrogen peroxide with an adjustable concentration. The generated hydrogen peroxide can be directly sprayed onto the soil surface for in-situ remediation. For example, the electrolyte is a sodium sulfate solution with a concentration of 0.05 mol / L. The electrolyte flow rate is 10 mL / min; the total gas flow rate is 700 mL / min.

[0085] like Figure 3 As shown, the end plate 11 has multiple positioning holes around its perimeter for connecting the reactor 2 via bolts. From left to right, the upper side of the end plate 11 has the anolyte outlet, gas outlet, and catholyte outlet; the lower side has the catholyte inlet, gas inlet, and anolyte inlet. The end plate symmetry plate 20 is symmetrical to the end plate 11.

[0086] like Figure 4 As shown, on the upper side of the double-sided anode panel 18, from left to right, are the anode liquid flow hole, the gas channel, and the cathode liquid flow hole; on the lower side, from left to right, are the cathode liquid flow hole, the gas channel, and the anode liquid flow hole.

[0087] like Figure 5 As shown, on the upper side of the gas plate 15, from left to right, are the anolyte flow hole, the gas channel, and the cathode flow hole; on the lower side, from left to right, are the cathode flow hole, the gas channel, and the anolyte flow hole.

[0088] like Figure 6 As shown, from left to right, the upper side of the cathode plate 14 has an anolyte flow hole, a gas channel, and a cathode liquid flow hole; the lower side also has the same configuration from left to right. When the cathode plate 14 is flipped, it becomes the anode flow channel plate 13, with the striped flow channel aligned with the anode; when the cathode plate 14 is chirally symmetrically mounted (with the toothed flow channel facing the gas plate 15), it becomes the cathode plate symmetry plate 16. The anode flow channel plate symmetry plate 17 is structurally symmetrical to the anode flow channel plate 13.

[0089] like Figure 7As shown, from left to right, the upper side of the anode plate 12 consists of an anolyte flow hole, a gas channel, and a cathode flow hole; the lower side also consists of a cathode flow hole, a gas channel, and an anolyte flow hole. The anode plate 12 and the anode plate symmetry plate 19 are structurally symmetrical.

[0090] like Figure 2 As shown, the anolyte enters through the anolyte inlet, flows into the cavity formed by the anode plate 12 and the anode flow channel plate 13, and exits through the anolyte outlet. The catholyte enters through the catholyte inlet, flows into the cavity of the cathode plate 14 or the symmetrical cathode plate 16, and exits through the catholyte outlet. Gas enters through the gas inlet, flows into the gas plate 15, and exits through the gas outlet. Hydrogen peroxide is generated in the catholyte cavity and flows out through the catholyte outlet along with the catholyte. For example, the catholyte is a 0.05 mol / L sodium sulfate solution.

[0091] Furthermore, the hydrogen peroxide generating device for ex-situ soil remediation also includes: an inlet pipe 5, an outlet pipe 6, a spraying device, a spraying pipe 7, and an outlet tank 9;

[0092] The liquid inlet tank 8 is connected to the reactor 2 via the liquid inlet water pipe 5;

[0093] The reactor 2 is connected to the liquid outlet tank 9 via the liquid outlet pipe 6;

[0094] The liquid outlet tank 9 is connected to the spraying equipment via the spray pipe 7. Figure 1 (Not shown in the image) Connection.

[0095] The inlet tank 8 contains the electrolyte, and the outlet tank 9 stores the prepared hydrogen peroxide.

[0096] During soil remediation, the electrolyte enters the reactor 2 from the inlet tank 8 and begins an electrocatalytic reaction to produce hydrogen peroxide. After a series of electrocatalytic reactions, the electrolyte generates hydrogen peroxide, which then enters the outlet water pipe 6 from the reactor 2 and then the outlet tank 9. The hydrogen peroxide solution is then pumped from the outlet tank 9 into the hydrogen peroxide spraying equipment via the spray pipe 7 to spray the soil in the soil pile 10 in situ for subsequent soil remediation.

[0097] Furthermore, the hydrogen peroxide generator for ex-situ soil remediation also includes: a solar panel 1, a solar controller 3, and a battery 4;

[0098] The solar panel 1 is connected to the solar controller 3;

[0099] The solar controller 3 is connected to the storage battery 4;

[0100] The solar controller 3 is connected to the reactor 2.

[0101] The hydrogen peroxide generator for ex-situ soil remediation of this invention enables green on-site production of hydrogen peroxide, thereby significantly improving production efficiency and environmental performance. Specifically, the device exhibits excellent stability, ensuring continuous and stable hydrogen peroxide production. Simultaneously, the device operates at relatively low cost, resulting in high economic benefits. Operationally, the design is simple and easy to understand, allowing users to easily master its use, further enhancing its practicality and convenience. In summary, this invention not only overcomes the shortcomings of existing technologies but also provides a novel, efficient, economical, environmentally friendly, and easy-to-operate solution for on-site hydrogen peroxide preparation.

[0102] Furthermore, the membrane includes a proton exchange membrane, a cation exchange membrane, and an anion exchange membrane.

[0103] The diaphragm uses a commercially available cation exchange membrane, such as a DuPont proton exchange membrane. For example, the diaphragm is a perfluorinated cation exchange membrane.

[0104] Furthermore, the anode electrode comprises a ruthenium-iridium titanium plate and an iron-nickel doped foam nickel plate.

[0105] Furthermore, the thickness of the ruthenium-iridium titanium plate ranges from 0.5 to 2 mm;

[0106] The ruthenium loading in the ruthenium-iridium-titanium plate is 6-8 g / m³. 2 The iridium loading is 2-4 g / m 2 .

[0107] For example, the thickness of the ruthenium-iridium titanium plate ranges from 1 mm;

[0108] The ruthenium loading in the ruthenium-iridium-titanium plate is 7 g / m². 2 The iridium loading is 3 g / m 2 .

[0109] Based on the excellent conductivity of ruthenium and iridium, and the ability of their oxides to reduce overpotential, energy loss can be effectively reduced, and electrolysis efficiency and reaction rate can be improved. In terms of corrosion resistance, the strong antioxidant and corrosion-resistant capabilities of ruthenium and iridium oxides allow them to remain stable in complex chemical environments, preventing electrolyte contamination and ensuring high purity of the electrolytic products. Regarding mechanical properties, a thickness of 0.5-2 mm provides good dimensional stability, maintaining stable electrode spacing and cell voltage. Simultaneously, the titanium substrate provides high strength and toughness, withstanding mechanical stress and preventing electrode deformation or damage during use. From an economic cost perspective, this parameter not only makes reasonable use of precious metals such as ruthenium and iridium, reducing their usage while ensuring performance and thus controlling costs, but also reduces electrode replacement frequency, equipment maintenance costs, and production downtime due to its long service life, resulting in considerable economic benefits.

[0110] Furthermore, the method for preparing the ruthenium-iridium-titanium plate is as follows:

[0111] The titanium sheet is surface-polished to make it flat;

[0112] The titanium sheet was alkaline washed with a sodium hydroxide solution with a mass concentration of 4-8% for 1-3 hours to remove surface grease.

[0113] After alkaline washing, the titanium sheet is placed in an oxalic acid solution with a mass concentration of 4-8% for acid etching for 1-3 hours, then rinsed with water and dried.

[0114] Ruthenium oxide and iridium oxide were dissolved in a mixed solution of isobutanol, isopropanol, and concentrated hydrochloric acid, and then sprayed onto a dried titanium sheet using ultrasonic spraying. The sheet was then dried at 60-85°C to ensure complete solvent evaporation. The titanium sheet coated with the solution was then thermally decomposed at 400-500°C, causing the metal salts to decompose into the corresponding metal oxides and adhere to the electrode surface. This step was repeated multiple times to obtain a uniform and stable oxide coating on the surface of the titanium sheet.

[0115] After thermal decomposition, the titanium sheet with oxide coating is cooled to room temperature to obtain the anode electrode.

[0116] Furthermore, the volume ratio of isobutanol, isopropanol, and concentrated hydrochloric acid is 2-3:2-3:1. The concentrated hydrochloric acid is used to dissolve ruthenium oxide and iridium oxide, converting them into chloride salts, which are then dissolved in the alcohol solution. This ratio yields the best-dispersed mixed solution, resulting in optimal OER performance after spraying.

[0117] Isobutanol and isopropanol are of analytical grade, and the concentrated hydrochloric acid concentration is 12 mol / L. For example, the volume ratio of isobutanol, isopropanol, and concentrated hydrochloric acid is 2:2:1.

[0118] Furthermore, the cathode electrode uses carbon paper as a substrate and carbon-based materials as catalysts; wherein, the carbon-based materials include carbon black and modified carbon black;

[0119] The carbon paper has a thickness of 0.1-0.5 mm and a resistivity of <7 mΩ·cm;

[0120] The loading of carbon-based materials is 20-50 g / m³. 2 At low loading, catalytic performance improves with increasing loading. Beyond this range, catalytic performance cannot be further improved. From a cost perspective, this range is optimal.

[0121] For example, the carbon paper has a thickness of 0.2 mm and a resistivity of 5 mΩ·cm; the loading of carbon-based material is 38 g / m. 2 .

[0122] Furthermore, the method for preparing the cathode electrode is as follows:

[0123] Using 80-120 mesh copper mesh (purple copper mesh) and carbon paper (thickness 0.1-0.5 mm, resistivity <7 mΩ·cm) as the substrate, carbon-based materials (various carbon blacks, modified carbon blacks), for example, conductive carbon black (Super P), are etched with concentrated nitric acid at 70-90℃ for 8-48 hours (for example, 24 hours). After cooling, the carbon-based materials are washed with deionized water and anhydrous ethanol, centrifuged, and dried at 70-90℃ for 24 hours to obtain O-sp carbon black, which is used for slurry preparation.

[0124] Slurry preparation method: Mix anhydrous ethanol (analytical grade), distilled water, and polytetrafluoroethylene (PTFE) coating at a volume ratio of 2:1:0.05 until homogeneous. Add O-sp carbon black in proportion, stir, and ultrasonically mix until homogeneous. Ultrasonically spray the mixture onto both sides of the copper mesh until it is completely covered. Hot-press the copper mesh and raw carbon paper at 70-90℃ to form a shape, and seal the edges with PEN sealing film. It is worth noting that a certain amount of tab is left on one side of the copper mesh for use as a current collector, thus obtaining the cathode electrode. For example, the PTFE coating model is FW-8800.

[0125] Multiple reactors 2 are connected in parallel via a power supply parallel connection, with cathode gas and anolyte each fed into separate inlet pipelines. Reactor 2 is modular, and the number of reactors 2 can be adjusted according to needs. A certain number of reactors 2 connected in parallel form a hydrogen peroxide production unit, connected to a commercially available solar power system. The produced hydrogen peroxide of different concentrations will be used for soil remediation. Analysis data for different concentrations of hydrogen peroxide production are shown in Table 1.

[0126] Table 1 Production of hydrogen peroxide at different concentrations

[0127]

[0128] The hydrogen peroxide generator for ex-situ soil remediation of this invention has advantages such as miniaturization, on-site preparation, impurity-free operation, and flexible concentration adjustment. It can work in conjunction with relevant chemical remediation technologies and equipment to achieve rapid soil remediation. Furthermore, the electrochemical equipment is easy to install and operate, and can be quickly put into use, making it particularly suitable for remote areas lacking corresponding hydrogen peroxide production facilities.

[0129] This invention also discloses a soil remediation method based on the above-mentioned hydrogen peroxide generator for ex-situ soil remediation, comprising the following steps:

[0130] Hydrogen peroxide was prepared using a hydrogen peroxide generator and used to pretreat the contaminated soil. The pretreatment process involved screening the petroleum hydrocarbon contaminated soil to be remediated to separate out larger particles and gravel.

[0131] Add a reducing agent to the contaminated soil while stirring. During the stirring process, add a certain amount of water to the contaminated soil to ensure that the reducing agent can play a full role and reduce for a set time.

[0132] Ferrous sulfate was added to hydrogen peroxide in a certain proportion, and the hydrogen peroxide was sprayed onto the contaminated soil. Then the mixture was stirred and the oxidation treatment was carried out for a set time.

[0133] The reducing agent is zero-valent iron.

[0134] Furthermore, the concentration of the hydrogen peroxide is 0.1-3% (mass fraction).

[0135] Furthermore, the reducing agent is 1-3% (mass fraction) of the contaminated soil.

[0136] The hydrogen peroxide is 10-30% (mass fraction) of the contaminated soil.

[0137] The ferrous sulfate is 0.5-2% (mass fraction) of the hydrogen peroxide.

[0138] The above-mentioned soil remediation methods can effectively remediate contaminated soil, significantly reduce or remove the content of pollutants in the soil, and improve environmental pollution.

[0139] The soil remediation method employed a zero-valent iron (ZVFe)-Fenton coupling process to remediate contaminated soil. The moderately contaminated soil was collected from a slag yard. The main pollutants in this soil included petroleum hydrocarbons and various halogenated hydrocarbons, as well as benzene series contamination (phenol and nitrobenzene, etc.). Remediation experiments were conducted on the actual contaminated soil after pretreatment. The petroleum hydrocarbon-contaminated soil to be remediated was pre-screened to remove larger particles and debris. The overall dosage principle for the reagents was: 300g moderately contaminated soil + ZVFe - reduction curing for 1-3 days + ferrous iron + hydrogen peroxide (2%) - oxidation for 2-4 days. The optimal remediation process was obtained by adjusting the dosages of ZVFe, hydrogen peroxide, and ferrous iron (see Table 2). Samples were taken, tested, and the effectiveness was evaluated. The amount of ferrous sulfate added was 1% of the mass of hydrogen peroxide.

[0140] Table 2 Summary of reagent dosages in laboratory small-scale tests

[0141]

[0142] Compared to the pre-remediation moderately contaminated soil (see Table 3), the zero-valent iron-Fenton coupling process showed significant effectiveness in remediating moderately contaminated soil. The removal rates of benzene series pollutants such as phenol and nitrobenzene reached over 99%, chlorinated hydrocarbons over 80%, and petroleum hydrocarbons 40%. As shown in Table 4, the concentrations of various pollutants in the soil were measured after 1 day of reduction curing and 2 days of oxidation; Table 5 shows the concentrations after 3 days of reduction curing and 4 days of oxidation. The results indicate that the Fenton-zero-valent iron coupling process effectively removes numerous harmful organic pollutants such as petroleum hydrocarbons, chlorinated hydrocarbons, nitrobenzene, and phenol from the soil. The optimal remediation effect was achieved when the zero-valent iron dosage was 3% and the hydrogen peroxide dosage was 30% after 3 days of remediation. Increasing the remediation time to 7 days, while potentially reducing pollutant levels further, did not significantly improve the overall effect.

[0143] Table 3 Concentrations of various pollutants in contaminated soil

[0144]

[0145] Table 4 Concentrations of various pollutants 3 days after contaminated soil remediation

[0146] process 1 2 3 4 Iron dosage (by mass) 1.5％ 3％ 1.5％ 3％ Hydrogen peroxide dosage (mass ratio) 15％ 15％ 30％ 30％ <![CDATA[Restored C 10 -C 40 (mg / kg)]]> 116 103 86 75.4 Phenol (mg / kg) after repair 8.3 2.1 0.2 0.1 Nitrobenzene after repair (mg / kg) 2.1 1.9 0.7 0.8 Post-remediation chlorinated hydrocarbons (mg / kg) 10.5 8.1 5.3 5.9

[0147] Table 5 Concentrations of various pollutants 7 days after contaminated soil remediation

[0148]

[0149]

[0150] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydrogen peroxide generator for ex-situ soil remediation, characterized in that, include: Reactor (2) and inlet tank (8); The reactor (2) is connected to the liquid inlet tank (8); The reactor (2) comprises, in sequence, end plates (11), anode plates (12), anode electrodes, anode flow channel plates (13), diaphragms, cathode plates (14), cathode electrodes, gas plates (15), cathode electrodes, cathode plate symmetry plates (16), diaphragms, anode flow channel plate symmetry plates (17), anode electrodes, anode double-sided plates (18), anode flow channel plates (13), diaphragms, cathode plates (14), cathode electrodes, gas plates (15), cathode electrodes, cathode plate symmetry plates (16), diaphragms, anode flow channel plate symmetry plates (17), anode electrodes, anode plate symmetry plates (19), and end plate symmetry plates (20).

2. The hydrogen peroxide generator for ex-situ soil remediation according to claim 1, characterized in that, Also includes: Inlet water pipe (5), outlet water pipe (6), spray equipment, spray pipe (7) and outlet tank (9); The liquid inlet tank (8) is connected to the reactor (2) via a liquid inlet water pipe (5); The reactor (2) is connected to the liquid outlet tank (9) via a liquid outlet pipe (6); The liquid outlet tank (9) is connected to the spraying equipment via the spray pipe (7).

3. The hydrogen peroxide generator for ex-situ soil remediation according to claim 1 or 2, characterized in that, Also includes: Solar panel (1), solar controller (3), and storage battery (4); The solar panel (1) is connected to the solar controller (3); The solar controller (3) is connected to the storage battery (4); The solar controller (3) is connected to the reactor (2).

4. The hydrogen peroxide generator for ex-situ soil remediation according to claim 1, characterized in that, The membrane includes a proton exchange membrane, a cation exchange membrane, and an anion exchange membrane.

5. The hydrogen peroxide generator for ex-situ soil remediation according to claim 1, characterized in that, The anode electrode comprises a ruthenium-iridium titanium plate and an iron-nickel doped foam nickel plate.

6. The hydrogen peroxide generating device for ex-situ soil remediation according to claim 5, characterized in that, The thickness of the ruthenium-iridium titanium plate ranges from 0.5 to 2 mm; The ruthenium loading in the ruthenium-iridium-titanium plate is 6-8 g / m³. 2 The iridium loading is 2-4 g / m 2 .

7. The hydrogen peroxide generating device for ex-situ soil remediation according to claim 5 or 6, characterized in that, The preparation method of the ruthenium-iridium-titanium plate is as follows: The titanium sheet undergoes surface polishing. The titanium sheet was alkali-washed for 1-3 hours using a sodium hydroxide solution with a mass concentration of 4-8%. After alkaline washing, the titanium sheet is placed in an oxalic acid solution with a mass concentration of 4-8% for acid etching for 1-3 hours, then rinsed with water and dried. Ruthenium oxide and iridium oxide are dissolved in a mixed solution of isobutanol, isopropanol and concentrated hydrochloric acid, and then sprayed onto a dried titanium sheet by ultrasonic spraying. The sheet is then dried at 60-85°C and thermally decomposed at 400-500°C. This process is repeated multiple times to obtain an oxide coating on the surface of the titanium sheet. The titanium sheet with an oxide coating is cooled to room temperature to obtain the anode electrode.

8. The hydrogen peroxide generating device for ex-situ soil remediation according to claim 7, characterized in that, The volume ratio of isobutanol, isopropanol, and concentrated hydrochloric acid is 2-3:2-3:

1.

9. The hydrogen peroxide generator for ex-situ soil remediation according to claim 1, characterized in that, The cathode electrode uses carbon paper as a substrate and carbon-based materials as catalysts; wherein, the carbon-based materials include carbon black and modified carbon black; The carbon paper has a thickness of 0.1-0.5 mm and a resistivity of <7 mΩ·cm; The loading of carbon-based materials is 20-50 g / m³. 2 .

10. The hydrogen peroxide generating device for ex-situ soil remediation according to claim 9, characterized in that, The method for preparing the cathode electrode is as follows: The carbon-based material was etched in concentrated nitric acid at 70-90℃ for 8-48 hours. After cooling, it was washed with deionized water and anhydrous ethanol, then centrifuged and dried at 70-90℃ to obtain O-sp carbon black. Anhydrous ethanol, distilled water and polytetrafluoroethylene coating are mixed evenly in a volume ratio of 2:1:0.

05. Then O-sp carbon black is added, stirred and ultrasonically mixed evenly, and then ultrasonically sprayed onto both sides of an 80-120 mesh copper mesh until the copper mesh is completely covered. The cathode electrode is obtained by hot pressing copper mesh and carbon paper at 70-90℃.

11. The hydrogen peroxide generator for ex-situ soil remediation according to claim 1, characterized in that, The operating voltage of the reactor (2) is 1.5V-5V.

12. The hydrogen peroxide generating device for ex-situ soil remediation according to claim 1 or 11, characterized in that, The electrolyte in the reactor (2) is a sodium sulfate solution; The flow rate of the electrolyte is 5–30 mL / min.

13. The hydrogen peroxide generating device for ex-situ soil remediation according to claim 1 or 11, characterized in that, The gas in the reactor (2) is air or oxygen; The gas flow rate is 400–1000 mL / min.

14. A soil remediation method based on a hydrogen peroxide generator for ex-situ soil remediation according to any one of claims 1-13, characterized in that, Includes the following steps: Hydrogen peroxide was prepared using a hydrogen peroxide generator and used for pretreatment of contaminated soil. Add a reducing agent to the contaminated soil and stir it evenly. During the stirring process, add a certain amount of water to the contaminated soil and set a reduction time. Ferrous sulfate was added to hydrogen peroxide in a certain proportion, and the hydrogen peroxide was sprayed onto the contaminated soil for an oxidation treatment time.

15. The soil remediation method according to claim 14, characterized in that, The concentration of the hydrogen peroxide is 0.1-3%.

16. The soil remediation method according to claim 14, characterized in that, The reducing agent is 1-3% of the mass of the contaminated soil; The hydrogen peroxide is 10-30% of the mass of the contaminated soil; The ferrous sulfate content is 0.5-2% of the mass of hydrogen peroxide.

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