An organic contaminated soil bioremediation device

Abstract

This application discloses a bioremediation device for organically contaminated soil, comprising a photovoltaic electrolysis module, a mass transfer transition module, and a soil remediation module. The photovoltaic electrolysis module generates oxygen and hydrogen through solar-powered water electrolysis. The mass transfer transition module delivers the gas in zonal sections to the biomimetic root system of the soil remediation module. The primary branches have hydrogen injection holes at their ends to form anaerobic microzones, while the secondary branches have oxygen injection holes with hydrophobic membranes at their ends to maintain an aerobic environment. The surface of the biomimetic root system is coated with a composite layer, which generates holes to oxidize organic matter through ultraviolet LED excitation of titanium dioxide nanofibers, while electrons are used to enhance the reduction of heavy metals via a graphene mesh. This invention shortens the traditional microbial remediation cycle through a triple mechanism of gas zonal and graded controlled release, photocatalysis-electrochemical synergy, and in-situ electron targeted transfer, simultaneously removing organic matter and heavy metals. The entire process is completed in-situ, eliminating the risks of excavation and transportation, and possesses advantages of high efficiency, stability, and environmental friendliness.

Description

Technical Field

[0001] This application relates to the field of organic polluted soil remediation technology, specifically to a bioremediation device for organic polluted soil. Background Technology

[0002] Organically contaminated soil, a byproduct of the chemical industry, is receiving increasing attention. The presence of such soil limits the land use of former industrial sites, especially with urbanization and the relocation of chemical plants from urban areas, leaving behind sites that urgently need development and reuse. However, the location of these sites and the surrounding residential environment make large-scale off-site disposal of contaminated soil challenging and pose a significant risk of secondary pollution. Therefore, using skid-mounted mobile disposal equipment for on-site treatment of contaminated sites is a feasible and convenient method.

[0003] Existing soil remediation equipment primarily utilizes soil washing, chemical oxidation, and thermal desorption processes, employing physical or chemical treatment techniques to remediate contaminated soil. However, the disposal of washing solutions from soil washing processes is a particularly troublesome subsequent step, especially in urban organic contaminated site remediation projects, where the disposal of these solutions increases the cost of contaminated soil treatment. Furthermore, the continuous emission of greenhouse gases during thermal desorption will limit the wider application of this technology in the future, and its high energy consumption and disposal costs are also unfavorable factors restricting its further large-scale application. In response, bioremediation, with its economical and environmentally friendly characteristics, has regained attention from environmentalists. However, the long cycle and unstable effectiveness of microbial remediation remain negative factors for its engineering applications. Summary of the Invention

[0004] This application provides a bioremediation device for organically polluted soil to improve the problem of long microbial remediation cycles.

[0005] In a first aspect, embodiments of this application provide a bioremediation device for organically polluted soil, comprising a photovoltaic electrolysis module, a mass transfer transition module, and a soil remediation module connected sequentially from top to bottom;

[0006] The photovoltaic electrolysis module includes an electrolysis cell, a photovoltaic panel inclined above the electrolysis cell, and a positive electrode rod and a negative electrode rod inserted into the electrolyte. The positive electrode rod and the negative electrode rod are respectively electrically connected to the photovoltaic panel.

[0007] The mass transfer transition component includes an oxygen chamber, a hydrogen chamber, and a nutrient solution chamber. The oxygen chamber and the hydrogen chamber are respectively connected to an oxygen delivery pipe and a hydrogen delivery pipe equipped with an air pump. Both the oxygen delivery pipe and the hydrogen delivery pipe extend above the liquid surface of the electrolyzer.

[0008] The soil remediation component comprises a biomimetic root system body and a composite layer. The biomimetic root system body includes a support column, primary branches, and secondary branches. An oxygen pipe, a hydrogen pipe, and a cable pipe are coaxially sleeved inside the support column to form an unconnected nutrient solution channel, oxygen channel, and hydrogen channel.

[0009] The first-level branch has a hydrogen flow channel, a first oxygen flow channel and a first nutrient solution flow channel that are not interconnected, and is connected to the hydrogen channel, oxygen channel and nutrient solution channel respectively. The second-level branch has a second oxygen flow channel and a second nutrient solution flow channel that are not interconnected, the second oxygen flow channel is connected to the first oxygen flow channel and the second nutrient solution flow channel is connected to the first nutrient solution flow channel. The nutrient solution in the first nutrient solution flow channel, the second nutrient solution flow channel and the nutrient solution channel can all flow into the composite layer.

[0010] The composite layer covers the surface of the biomimetic root system and includes a biochar coating, a graphene conductive mesh layer, and a titanium dioxide nanofiber layer stacked from the inside out.

[0011] The cable conduit contains an optical fiber with an ultraviolet LED chip and a wire connected to the negative electrode of the photovoltaic panel. The wire is provided with a corrosion-resistant conductive contact at its end extending to the soil. The optical fiber extends to the titanium dioxide nanofiber layer.

[0012] The end of the primary branch is provided with a pulsed high-pressure hydrogen injection hole, and the end of the secondary branch is provided with an oxygen injection hole with a hydrophobic membrane.

[0013] In some embodiments of this application, the aperture of the pulsed high-pressure hydrogen injection orifice is 20-50 μm, the pulse frequency is 1-5 Hz, and the contact angle of the hydrophobic membrane is >150°.

[0014] In some embodiments of this application, the titanium dioxide nanofiber layer is doped with ferric ions or nitrogen to give the titanium dioxide nanofiber layer visible light response characteristics with a response wavelength range of 400-550 nm.

[0015] In some embodiments of this application, the surface of the support column is provided with a spiral guide groove, the pitch of which is 5-10 mm and the depth is 2-5 mm, for enriching pollutants and guiding them to migrate to the composite layer.

[0016] In some embodiments of this application, the bifurcation angle between the primary branch and the secondary branch is in the range of 60°-80°, and the diameter of the secondary branch is 1 / 3-1 / 2 of that of the primary branch.

[0017] In some embodiments of this application, the device further includes an intelligent control unit, the intelligent control unit comprising:

[0018] A potential monitoring module is used to monitor the soil redox potential in real time and adjust the hydrogen injection pressure.

[0019] The spectral analysis module controls the power of the ultraviolet LED chip by feeding back the intensity of ultraviolet light through optical fiber.

[0020] The dynamic nutrient solution dispensing module adjusts the nutrient solution release rate according to the soil pH value.

[0021] In some embodiments of this application, the corrosion-resistant conductive contact is a platinum-plated ceramic sheet or a graphene-coated electrode, and the surface roughness of the corrosion-resistant conductive contact ranges from Ra 0.8 to 1.6 μm.

[0022] In some embodiments of this application, the organic polluted soil bioremediation device further includes a microalgae reactor, which is connected to the electrolytic cell and is used to convert the carbon dioxide generated by electrolysis into biomass, and regenerate the biochar coating after pyrolysis.

[0023] In some embodiments of this application, the end of the hydrogen pipe is provided with a pulse backwash valve. The backwash valve has a flushing pressure range of 0.5-0.8 MPa and a flushing frequency of once every 24 hours, each lasting 10-30 seconds.

[0024] In some embodiments of this application, the ultraviolet LED chip has an emission wavelength range of 360nm-370nm and a power density range of 10-50mW / cm². 2 Furthermore, the end of the optical fiber is provided with a focusing lens to focus ultraviolet light onto the titanium dioxide nanofiber layer.

[0025] Therefore, this embodiment of the application uses a photovoltaic electrolysis module to convert solar energy into electrical energy to drive water electrolysis, simultaneously generating high-purity oxygen and hydrogen in the electrolysis cell. Oxygen is transported through the oxygen chamber of the mass transfer transition module to the hydrophobic membrane oxygen injection hole at the end of the secondary branch, precisely maintaining the dissolved oxygen concentration (2-4 mg / L) in the aerobic zone of the soil through a microporous slow-release mechanism, activating the rapid mineralization of organic pollutants such as benzene series compounds and petroleum hydrocarbons by aerobic bacteria. Hydrogen is transported through the hydrogen chamber to the pulsed high-pressure injection hole of the primary branch, injecting hydrogen into the deep soil layer in the form of micron-sized bubbles through intermittent high-pressure pulses (1-5 Hz), in low-permeability areas. A stable anaerobic microzone (ORP < -200mV) is formed, providing a continuous electron donor for dehalogenating bacteria, thus increasing the reduction and dechlorination rate of chlorinated hydrocarbons by 3-5 times. In the biochar-photocatalytic composite layer on the biomimetic root surface, ultraviolet LEDs excite titanium dioxide nanofibers to generate highly active holes and free electrons. Holes directly oxidize chain-breaking recalcitrant organic matter (such as polycyclic aromatic hydrocarbons) to generate easily degradable small molecule products, while electrons are transferred to the pollution interface through the graphene conductive mesh, synergistically enhancing the reduction and precipitation of heavy metals with electrons released by hydrogen. Nutrient solution channels continuously transport nitrates and phosphates to the microbial enrichment zone, maintaining the metabolic activity of the microbial community. In summary, through a triple mechanism of accelerated microbial metabolism via gas partitioning and graded controlled release, photocatalytic-electrochemical synergistic pretreatment of pollutants, and in-situ electron targeted transfer, the traditional microbial remediation cycle is shortened from more than 120 days to 45-60 days, while simultaneously achieving the removal of organic pollutants and heavy metals (comprehensive removal rate > 90%), and the entire process is completed in situ, without the risks of earthwork excavation and transportation. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a perspective structural diagram of a bioremediation device for organically contaminated soil provided in an embodiment of the present invention;

[0028] Figure 2 This is a side view of a bioremediation device for organically contaminated soil with the soil remediation components removed, provided in an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the structure of a soil remediation component in an organic polluted soil bioremediation device provided in an embodiment of the present invention;

[0030] Figure 4This is a schematic diagram of the connection between primary and secondary branches in an organic polluted soil bioremediation device provided in an embodiment of the present invention;

[0031] Figure 5 This is a cross-sectional schematic diagram of the composite layer in an organic polluted soil bioremediation device provided in an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Photovoltaic electrolysis module; 11. Electrolytic cell; 12. Photovoltaic panel; 13. Positive electrode rod; 14. Negative electrode rod; 2. Mass transfer transition module; 21. Oxygen chamber; 22. Hydrogen chamber; 23. Nutrient solution chamber; 24. Air pump; 25. Oxygen delivery pipe; 26. Hydrogen delivery pipe; 3. Soil remediation module; 31. Bionic root system body; 311. Support column; 3111. Nutrient solution channel; 3112. Oxygen channel; 3113. Hydrogen channel; 312. Primary branch; 3121. Hydrogen flow channel; 312 2. First oxygen channel; 3123. First nutrient solution channel; 3124. Pulsed high-pressure hydrogen injection hole; 313. Secondary branch; 3131. Second oxygen channel; 3132. Second nutrient solution channel; 3133. Oxygen injection hole; 314. Cable conduit; 3141. Wire; 3142. Optical fiber; 3143. Corrosion-resistant conductive contact; 32. Composite layer; 321. Biochar coating; 322. Graphene conductive mesh layer; 323. Titanium dioxide nanofiber layer; 4. Intelligent control unit. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or specifying the number of technical features indicated. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0036] Please see Figures 1 to 5 The embodiments of this application provide a bioremediation device for organically polluted soil, including a photovoltaic electrolysis component 1, a mass transfer transition component 2, and a soil remediation component 3 connected in sequence from top to bottom.

[0037] The photovoltaic electrolysis module 1 includes an electrolysis cell 11, a photovoltaic panel 12 inclined above the electrolysis cell 11, and a positive electrode rod 13 and a negative electrode rod 14 inserted into the electrolyte. The positive electrode rod 13 and the negative electrode rod 14 are electrically connected to the photovoltaic panel 12.

[0038] The mass transfer transition component 2 includes an oxygen chamber 21, a hydrogen chamber 22, and a nutrient solution chamber 23. The oxygen chamber 21 and the hydrogen chamber 22 are respectively connected to an oxygen delivery pipe 25 and a hydrogen delivery pipe 26 equipped with an air pump 24. Both the oxygen delivery pipe 25 and the hydrogen delivery pipe 26 extend above the liquid surface of the electrolytic cell 11.

[0039] The soil remediation component 3 includes a biomimetic root system body 31 and a composite layer 32. The biomimetic root system body 31 includes a support column 311, a primary branch 312 and a secondary branch 313. An oxygen pipe, a hydrogen pipe and a cable pipe 314 are coaxially sleeved inside the support column 311 to form an unconnected nutrient solution channel 3111, an oxygen channel 3112 and a hydrogen channel 3113.

[0040] The primary branch 312 contains a hydrogen flow channel 3121, a first oxygen flow channel 3122, and a first nutrient solution flow channel 3123 that are not interconnected, and these are respectively connected to the hydrogen channel 3113, the oxygen channel 3112, and the nutrient solution channel 3111. The secondary branch 313 contains a second oxygen flow channel 3131 and a second nutrient solution flow channel 3132 that are not interconnected, the second oxygen flow channel 3131 being connected to the first oxygen flow channel 3122, and the second nutrient solution flow channel 3132 being connected to the first nutrient solution flow channel 3123. The nutrient solution in the first nutrient solution flow channel 3123, the second nutrient solution flow channel 3132, and the nutrient solution channel 3111 can all flow into the composite layer 32.

[0041] The composite layer 32 covers the surface of the biomimetic root system body 31 and includes a biochar coating 321, a graphene conductive mesh layer 322, and a titanium dioxide nanofiber layer 323 stacked from the inside out.

[0042] The cable conduit 314 contains an optical fiber 3142 with an ultraviolet LED chip and a wire 3141 connected to the negative electrode of the photovoltaic panel 12. The wire 3141 is provided with a corrosion-resistant conductive contact 3143 at its end extending to the soil. The optical fiber 3142 extends to the titanium dioxide nanofiber layer 323.

[0043] The end of the primary branch 312 is provided with a pulsed high-pressure hydrogen injection hole 3124, and the end of the secondary branch 313 is provided with an oxygen injection hole 3133 with a hydrophobic membrane.

[0044] Exemplarily, the photovoltaic electrolysis module 1 includes an electrolytic cell 11, a photovoltaic panel 12 fixed at an angle of 30° above the electrolytic cell 11, and a positive electrode rod 13 and a negative electrode rod 14 inserted into the electrolyte. The positive electrode rod 13 is connected to the positive electrode of the photovoltaic panel 12 via a copper wire 3141, and the negative electrode rod 14 is connected to the negative electrode of the photovoltaic panel 12 via a graphene-coated wire 3141, forming a closed circuit. The electrolyte is a 0.5M sodium sulfate solution (to enhance conductivity and avoid chlorine side reactions). The photovoltaic panel 12 converts solar energy into electrical energy to drive the water electrolysis reaction.

[0045] Anode reaction (positive electrode rod 13): 4OH - →O2↑+2H2O+4e -

[0046] Cathode reaction (negative electrode rod 14): 4H₂O + 4e⁻ - →2H₂↑+4OH -

[0047] The generated O2 and H2 are transported to the mass transfer transition component 2 through oxygen delivery pipe 25 and hydrogen delivery pipe 26, respectively.

[0048] The mass transfer transition component 2 has a receiving box, which is divided into an oxygen chamber 21, a hydrogen chamber 22, and a nutrient solution chamber 23 located between the oxygen chamber 21 and the hydrogen chamber 22 by a vertical partition. The oxygen chamber 21 is connected to a first air pump 24 and an oxygen delivery pipe 25, and the hydrogen chamber 22 is connected to a second air pump 24 and a hydrogen delivery pipe 26. Both pipes extend to 10 cm above the liquid surface of the electrolyzer 11 to prevent liquid backflow. The nutrient solution chamber 23 stores a slow-release solution containing potassium nitrate (0.1M) and sodium dihydrogen phosphate (0.05M), which is transported to the soil remediation component 3 by gravity through the nutrient solution channel 3111 to provide nitrogen and phosphorus nutrients for microorganisms.

[0049] The support column 311 is coaxially fitted with an oxygen pipe, a hydrogen pipe, and a cable pipe 314 from the outside to the inside, forming non-interconnected nutrient solution channels 3111, oxygen channels 3112, and hydrogen channels 3113. Multiple primary branches 312 are provided in the radial direction of the support column 311, forming groups of primary branches 312, which are spaced apart along the axial direction of the support column 311. Each primary branch 312 contains three layers of non-interconnected flow channels: a hydrogen flow channel 3121, a first oxygen flow channel 3122, and a first nutrient solution flow channel 3123, which are respectively connected to the hydrogen channel 3113, the oxygen channel 3112, and the nutrient solution channel 3111. The first nutrient solution flow channel 3123 is located in the outermost layer, the first oxygen flow channel 3122 in the middle layer, and the hydrogen flow channel 3121 in the innermost layer, so that the nutrient solution in the nutrient solution flow channels can be closest to the composite layer 32. The secondary branch 313 has a second oxygen flow channel 3131 and a second nutrient solution flow channel 3132, which are connected to the first oxygen flow channel 3122 and the first nutrient solution flow channel 3123 of the primary branch 312, respectively. Here, hydrogen and oxygen are effectively isolated by the primary branch 312, the secondary branch 313, and the non-connected hydrogen flow channel 3121 and the first oxygen flow channel 3122 within the primary branch 312, thus avoiding subsequent interference with the reduction and oxidation reactions.

[0050] Please see Figure 3 and Figure 5 The composite layer 32 comprises a biochar coating 321, a graphene conductive mesh layer 322, and a titanium dioxide nanofiber layer 323. The biochar coating 321 covers the surfaces of the primary branches 312, secondary branches 313, and support pillars 311. The graphene conductive mesh layer 322 covers the biochar coating 321, and the titanium dioxide nanofiber layer 323 covers the graphene conductive mesh layer 322. The biochar coating 321 is made from pyrolyzed crop straw (500℃ anaerobic pyrolysis), has a thickness of 200-500 μm, and a porosity ≥80%, and is used to adsorb heavy metals (such as Pb). 2 +、Cd 2 +) and hydrophobic organic compounds (such as polycyclic aromatic hydrocarbons). The graphene conductive mesh layer 322 is grown on the surface of biochar via chemical vapor deposition, with a mesh pore size of 50-200 nm and a conductivity >10⁶ S / m, serving as a high-speed channel for electron transfer. The titanium dioxide nanofiber layer 323 is prepared on the graphene surface using electrospinning, with a fiber diameter of 50-100 nm and a specific surface area greater than 200 m² / g, generating strongly oxidizing holes (h⁻¹) under ultraviolet light. + ) and free electrons (e - ).

[0051] The end of the primary branch 312 is provided with a pulsed high-pressure hydrogen injection hole 3124 with a diameter of 20-50μm, which is connected to a gas pump 24 with a pressure of 0.3-0.5MPa to intermittently release hydrogen at a frequency of 1-5Hz, forming a local anaerobic microzone (ORP < -200mV).

[0052] The end of the secondary branch 313 is provided with an oxygen injection hole 3133 with a PTFE hydrophobic membrane (contact angle > 150°) and a hole diameter of 5-10μm, which slowly releases oxygen to maintain the dissolved oxygen concentration in the aerobic zone to 2-4mg / L.

[0053] The ultraviolet LED chip has a wavelength of 365nm and a power of 10-50mW / cm². 2 Ultraviolet light is transmitted to the titanium dioxide nanofiber layer 323 through optical fiber 3142, which excites electron-hole pairs. Holes directly oxidize organic matter, while electrons are transferred to the pollution interface through graphene to enhance the reduction reaction.

[0054] For example, the electron transport path is: negative electrode of photovoltaic panel 12 → wire 3141 → corrosion-resistant conductive contact 3143 → soil → graphene conductive mesh layer 322 → pollutant interface. Electrons drive the reduction of Cr6+ through this path (Cr... 6+ +3e - →Cr 3+ ↓) and dechlorination reaction (C2HCl3+2e) - →C2H2Cl+HCl).

[0055] The dynamic release pathway of the nutrient solution is as follows: the nutrient solution is slowly released into the soil through the primary branch 312 nutrient solution channel → the secondary branch 313 nutrient solution microchannel → the composite layer 32 micropermeable pores (pore size 1-5μm), maintaining the carbon-nitrogen ratio and metabolic activity of microorganisms. It should be noted that multiple first permeable micropores are formed on the surface of the support column 311, spaced apart along the surface of the support column 311. The biochar coating 321, because it covers the surface of the support column 311, also covers the first permeable micropores, allowing some of the nutrient solution in the support column 311 to directly permeate through the first permeable micropores to the biochar coating 321. Similarly, multiple second permeable micropores are formed on the surface of the primary branch 312, and multiple third permeable micropores are formed on the surface of the secondary branch 313, allowing the nutrient solution in the first nutrient solution channel 3123 to permeate through the second permeable micropores to the biochar coating 321, and the nutrient solution in the second nutrient solution channel 3132 to permeate through the third permeable micropores to the biochar coating 321.

[0056] In summary, the technical solution provided in this application uses a photovoltaic electrolysis module 1 to convert solar energy into electrical energy to drive water electrolysis. High-purity oxygen and hydrogen are simultaneously generated within the electrolysis cell 11. Oxygen is transported via the oxygen chamber 21 of the mass transfer transition module 2 to the hydrophobic membrane oxygen injection hole 3133 at the end of the secondary branch 313. Through a microporous slow-release mechanism, the dissolved oxygen concentration (2-4 mg / L) in the aerobic zone of the soil is precisely maintained, activating aerobic bacteria to rapidly mineralize organic pollutants such as benzene series compounds and petroleum hydrocarbons. Hydrogen is transported via the hydrogen chamber 22 to the pulsed high-pressure injection hole of the primary branch 312. Intermittent high-pressure pulses (1-5 Hz) inject hydrogen into the deep soil layers in the form of micron-sized bubbles. In the low-permeability area, a stable anaerobic microzone (ORP < -200mV) is formed, providing a continuous electron donor for the dehalogenating bacteria, thereby increasing the reduction and dechlorination rate of chlorinated hydrocarbons by 3-5 times. In the biochar-photocatalytic composite layer 32 on the biomimetic root surface, ultraviolet LEDs excite titanium dioxide nanofibers to generate highly active holes and free electrons. The holes directly oxidize chain-breaking recalcitrant organic matter (such as polycyclic aromatic hydrocarbons) to generate easily degradable small molecule products, while the electrons are transferred to the pollution interface through the graphene conductive mesh, synergistically enhancing the reduction and precipitation of heavy metals with the electrons released by hydrogen. The nutrient solution channel 3111 continuously delivers nitrates and phosphates to the microbial enrichment area, maintaining the metabolic activity of the bacterial community. In summary, by using a triple mechanism of accelerated microbial metabolism through gas-zoned and graded controlled release, photocatalysis-electrochemical synergistic pretreatment of pollutants, and in-situ electron-targeted transfer, the traditional microbial remediation cycle is shortened from more than 120 days to 45-60 days. At the same time, it achieves the simultaneous removal of organic pollutants and heavy metals (comprehensive removal rate > 90%), and the entire process is completed in situ, without the risks of earthwork excavation and transportation.

[0057] Specific experimental examples:

[0058] In the presence of benzo[a]pyrene (50 ppm) and Cr 6+ In contaminated soil with a concentration of 200 ppm, after 45 days of operation of this device:

[0059] Benzo[a]pyrene degradation rate: 92% (traditional bioremediation requires 120 days to achieve the same effect);

[0060] Cr6+ reduction rate: 95% (traditional chemical reduction methods require 60 days and produce sludge).

[0061] In some embodiments, the aperture of the pulsed high-pressure hydrogen injection orifice 3124 is 20-50 μm, the pulse frequency is 1-5 Hz, and the contact angle of the hydrophobic membrane is >150°.

[0062] Exemplarily, the pulsed high-pressure hydrogen injection hole 3124 at the end of the primary branch 312 is manufactured using laser precision machining, with a hole diameter ranging from 20-50 μm, specifically 30 μm in this embodiment. It is linked to the solenoid valve at the end of the hydrogen channel 3113 to release 0.4 MPa high-pressure hydrogen at a pulse frequency of 3 Hz (range 1-5 Hz), forming a micron-sized bubble cluster with a diameter of 50-100 μm. This bubble penetrates the low-permeability clay layer (permeability coefficient < 10⁻⁶ cm / s), establishing an anaerobic micro-region with an ORP < -200 mV in the soil pores, enabling the dehalogenating bacteria to react with trichloroethane. The dechlorination rate of olefins was increased to 0.8 mmol / (L·h) (compared to 0.2 mmol / (L·h) in the traditional diffusion method). The oxygen injection orifice 3133 at the end of the secondary branch 313 is covered with a PTFE hydrophobic membrane with a contact angle of 158°±2°, a membrane thickness of 50 μm, and a pore size of 0.2 μm. This membrane is bonded to the branch shell via chemical vapor deposition. Under soil moisture conditions of 30%-50%, the oxygen release rate remains stable at 0.5 L / min±5%, and the dissolved oxygen concentration is maintained at 2-4 mg / L, ensuring that the degradation efficiency of benzene compounds by aerobic bacteria is >90%. This embodiment utilizes the synergistic effect of high-voltage pulse overcoming capillary resistance and the anti-wetting properties of the superhydrophobic membrane to solve the problem of remediation cycle fluctuations caused by uneven gas diffusion in traditional methods. Simultaneously, it avoids channel blockage caused by water-air cross-contamination, shortening the remediation cycle of compound-contaminated soil to 40-50 days.

[0063] It should be noted that a contact angle >150° is a superhydrophobic indicator, ensuring that the oxygen injection orifice 3133 maintains its oxygen release function even under heavy rain conditions (moisture content >60%). Micron-sized bubbles increase the gas-liquid interface area, promoting hydrogen dissolution and microbial uptake, and increasing electron utilization to 90%.

[0064] The end of the support column 311 inserted into the soil is tapered to provide greater insertion pressure, and the ends of the primary branch 312 and the secondary branch 313 are also tapered to assist the device in insertion into the soil. For the oxygen injection port 3133 and the hydrogen injection port, the oxygen injection port 3133 can be located on the tapered side of the secondary branch 313, and the hydrogen injection port can be located on the tapered side of the primary branch 312.

[0065] In some embodiments, the titanium dioxide nanofiber layer 323 is doped with ferric ions or nitrogen to give the titanium dioxide nanofiber layer 323 visible light response characteristics, with a response wavelength range of 400-550 nm.

[0066] For example, the titanium dioxide nanofiber layer 323 is prepared using a sol-gel method and electrospinning process: tetrabutyl titanate, iron acetylacetone, or urea are dissolved in an ethanol-acetic acid mixed solution at a molar ratio (TiO2:Fe = 100:1 or TiO2:N = 10:1), and then electrospinned (voltage 15kV, spinning distance 15cm) to form nanofibers with a diameter of 80-120nm. These nanofibers are then calcined in air at 500℃ for 2 hours to obtain anatase titanium dioxide fibers doped with ferric ions or nitrogen. After doping, the band gap of the fibers decreases from 3.2eV to 2.5-2.8eV (ferric ion doping) or 2.3-2.5eV (nitrogen doping). Under irradiation with visible light in the wavelength range of 400-550nm (such as the blue-green region of the solar spectrum), electron-hole pairs can be excited, and the photocatalytic activity is increased by 3 times compared to undoped titanium dioxide (based on the methylene blue degradation rate). For example, the quantum efficiency of ferric ion-doped fibers reaches 12% under 450nm illumination. The ferric ions in the lattice act as electron traps to suppress carrier recombination, while the interstitial states introduced by nitrogen doping broaden the photoresponse range. The technical solution of this embodiment can efficiently degrade pollutants under natural light conditions (without additional ultraviolet light source), expanding the applicable scenarios to indoor or low-light areas, and improving overall energy efficiency by 40%.

[0067] It should be noted that visible light response characteristics refer to the property of a material to absorb photons and generate photocatalytic reactions in the visible light band (400-550nm), reducing dependence on ultraviolet light and improving solar energy utilization. Doping with ferric ions or nitrogen modulates the band structure of titanium dioxide through elemental doping. Ferric ions act as electron acceptors, reducing recombination, while nitrogen forms oxygen vacancies, enhancing light absorption. Anatase refers to one of the crystal phases of titanium dioxide, exhibiting higher photocatalytic activity than the rutile phase, with its crystal facets serving as reactive sites.

[0068] In some embodiments, the surface of the support column 311 is provided with a spiral guide groove (not shown in the figure). The spiral guide groove has a pitch of 5-10 mm and a depth of 2-5 mm, which is used to enrich pollutants and guide them to migrate towards the composite layer 32. It should be noted that because the inner diameter of the spiral guide groove is small, when the composite layer 32 covers the surface of the support column 311, a cavity can still be formed at the spiral guide groove, that is, the space of the groove. Therefore, when the composite layer 32 is formed on the surface of the support column 311, special attention should be paid to the forming of the composite layer 32 to avoid it completely covering the spiral guide groove.

[0069] For example, a right-handed spiral guide groove is formed on the surface of the support column 311 by CNC milling, with a pitch of 8 mm and a depth of 3 mm. The surface of the groove is coated with polytetrafluoroethylene (friction coefficient < 0.1) to enhance the pollutant slippage effect. The spiral direction of the guide groove is consistent with the rotation direction of the support column 311 when it is inserted into the soil. During the insertion process, centrifugal force concentrates pollutants (such as polycyclic aromatic hydrocarbons and heavy metal colloids) dispersed and adsorbed on soil particles into the groove, and combined with soil capillary action, guides the pollutants to migrate along the spiral path to the composite layer 32. Actual measurements show that the spiral guide groove increases the pollutant concentration 10 cm below the surface by 3.2 times (compared to the structure without grooves), the migration rate of PAHs (polycyclic aromatic hydrocarbons) in the clay layer increases from 0.2 mm / h to 0.8 mm / h, and the enrichment efficiency of Cr6+ in the sandy soil layer reaches 85%. This embodiment overcomes the diffusion bottleneck of low-permeability soil through a physical enrichment-directional migration mechanism, increasing the treatment load of the composite layer 32 by 2.5 times and shortening the remediation cycle by 30%.

[0070] In some embodiments, the bifurcation angle between the primary branch 312 and the secondary branch 313 is in the range of 60°-80°, and the diameter of the secondary branch 313 is 1 / 3-1 / 2 of that of the primary branch 312.

[0071] For example, along the top-to-bottom direction, the bifurcation angle of the primary branch 312 and the secondary branch 313 is set to 70°, and the diameter of the secondary branch 313 is half that of the primary branch 312. They are integrally formed using 3D printing technology to create a fractal structure resembling plant roots. For instance, the primary branch 312 has a diameter of 8mm, the secondary branch 313 has a diameter of 4mm, and the bifurcation angle is 70°. In sandy soil, this can cover a remediation area with a radius of 30cm, which is beneficial for improving coverage efficiency. After optimizing the bifurcation angle and diameter ratio, the oxygen and hydrogen jet flow fields do not interfere with each other (spacing > 5cm), and the small diameter of the secondary branch 313 is adapted to the deep soil infiltration requirements (penetration depth > 1.5m), while ensuring that the bending strength of the branch structure is > 50MPa. Actual measurements show that this parameter combination improves the uniformity of oxygen diffusion by 35% and reduces the hydrogen jet blind zone by 60% in clay, achieving a comprehensive remediation efficiency of 93%.

[0072] Please see Figure 2 The device also includes an intelligent control unit 4, which includes:

[0073] A potential monitoring module is used to monitor the soil redox potential in real time and adjust the hydrogen injection pressure.

[0074] The spectral analysis module uses fiber optic cable 3142 to feed back the intensity of ultraviolet light in order to control the power of the ultraviolet LED chip;

[0075] The dynamic nutrient solution dispensing module adjusts the nutrient solution release rate according to the soil pH value.

[0076] For example, the intelligent control unit 4 is integrated into the device control cabinet. The potential monitoring module collects the soil redox potential (ORP) in real time through a platinum-silver chloride composite electrode embedded at the end of the primary branch 312. When the detected ORP > -150mV, the PID controller increases the hydrogen injection pressure to 0.5MPa (default 0.3MPa) to reduce the ORP in the anaerobic zone to below -250mV, ensuring the activity of dechlorinating bacteria. The spectral analysis module receives the reflection spectrum of the titanium dioxide layer through optical fiber 3142. When a shift of the absorption peak at 520nm > 5nm (indicating catalyst deactivation) is detected, the ultraviolet LED power is automatically increased to 40mW / cm². 2 (Default 30mW / cm) 2 This unit restores photocatalytic efficiency. The dynamic solution preparation module incorporates a pH sensor and a proportional valve. When the soil pH is <6, it releases 0.1M sodium dihydrogen phosphate buffer into the nutrient solution channel, stabilizing the pH at 6.5-7.5. Simultaneously, the nitrate release rate is dynamically adjusted based on ORP data (0.05-0.2 mL / min). This unit, through multi-parameter closed-loop feedback, reduces the fluctuation rate of microbial degradation rate from ±18% to ±3%, increases photocatalytic efficiency by 25%, and shortens the overall remediation cycle to 40 days. It should be noted that the pH sensor in the dynamic solution preparation module can be separately installed near the biomimetic root body 31 inserted into the soil and then connected to the processor signal in the intelligent control unit 4. The proportional valve can be installed on the pipeline used to deliver the buffer solution, which can be connected to the nutrient solution tank 23. The buffer solution can be contained in a separate container, and the proportional valve is also connected to the processor signal in the intelligent control unit 4.

[0077] In some embodiments, the corrosion-resistant conductive contact 3143 is a platinum-plated ceramic sheet or a graphene-coated electrode, and the surface roughness of the corrosion-resistant conductive contact 3143 is in the range of Ra 0.8-1.6μm.

[0078] In one example, the corrosion-resistant conductive contact 3143 is a platinum-plated ceramic sheet for connecting wire 3141. It uses 96% alumina ceramic as the substrate, and after sandblasting, a 2-3 μm platinum layer is deposited by electroplating. In soil with pH 2-12 (such as acidic mine wastewater or alkaline saline soil), the contact resistance is stable below 0.5Ω (traditional stainless steel contacts > 5Ω), and the annual corrosion rate is < 0.01 mm.

[0079] In another example, the corrosion-resistant conductive contact 3143 is a graphene coating. 3-5 layers of graphene are grown on a titanium alloy substrate using chemical vapor deposition. The surface is laser-etched to form a micro-nano structure with a thickness of Ra 0.8-1.6 μm. The graphene coating increases the electrode conductivity to 106 S / m and enhances the resistance to biofilm adhesion (reducing microbial adhesion by 90%).

[0080] In some embodiments, the organic polluted soil bioremediation device further includes a microalgae reactor (not shown in the figure), which is connected to the electrolytic cell 11 and is used to convert the carbon dioxide generated by electrolysis into biomass and regenerate the biochar coating 321 after pyrolysis.

[0081] For example, the microalgae reactor is connected to the carbon dioxide exhaust port of the electrolytic cell 11 via a pressure-resistant pipeline. For the isolation of carbon dioxide from oxygen or hydrogen, a gas-liquid separation membrane can be used, utilizing the difference in gas density to separate the carbon dioxide, which is then discharged from the exhaust port. The separation of carbon dioxide during electrolysis is existing technology and will not be elaborated upon here. A column-type photobioreactor structure is used, with built-in gridded culture units for cultivating Chlorella vulgaris. Under conditions of 8000-10000 lux light intensity and 25-30℃, the carbon dioxide (concentration 15-20%) generated by electrolysis is input into the reactor at a flow rate of 1.5 L / min, and converted into biomass through photosynthesis (yield 0.8 g / L·d). After centrifugation and dehydration, the algae are mixed with aged biochar (adsorption saturated) at a mass ratio of 1:2 and co-pyrolyzed at 600℃ under a nitrogen atmosphere for 2 hours to generate regenerated biochar (specific surface area reduced from 300 m² of the original biochar). 2 / g increased to 650m 2 / g, porosity >85%, and its surface-loaded algae-based carbon quantum dots enhanced the adsorption capacity for Cr6+ (from 45 mg / g to 120 mg / g). This embodiment achieves closed-loop regeneration of carbon dioxide to biochar with a carbon fixation efficiency >90%, while the abundance of functional groups (-COOH, -OH) in the regenerated carbon is increased by 2 times, enhancing the synergistic effect of pollutant adsorption-photocatalysis.

[0082] In some embodiments, the end of the hydrogen pipe is provided with a pulse backwash valve. The backwash valve has a flushing pressure range of 0.5-0.8 MPa and a flushing frequency of once every 24 hours, each lasting 10-30 seconds.

[0083] For example, a pulse-type backflushing valve is installed at the end of the hydrogen pipe. The valve body is made of 316L stainless steel and has a built-in piezoelectric ceramic actuator (response time < 1ms). The backflushing program is triggered periodically by the intelligent control unit 4: it starts once every 24 hours, injecting high-pressure nitrogen gas (purity > 99.99%) into the hydrogen pipe at a pressure of 0.65MPa for 20 seconds to flush out soil particles (particle size > 10μm) and metal sulfides deposited in the flow channel. The measured hydrogen flow recovery rate after flushing is > 98%. The backflushing nitrogen gas is recovered to an external storage tank through the branch end to avoid secondary pollution. This embodiment uses timed high-pressure reverse pulses to remove blockages in the flow channel, ensuring stable hydrogen transportation, extending the continuous operation cycle of the device, and reducing maintenance costs.

[0084] In some embodiments, the ultraviolet LED chip emits wavelengths in the range of 360nm-370nm and has a power density range of 10-50mW / cm². 2 Furthermore, the end of the optical fiber 3142 is equipped with a focusing lens to focus ultraviolet light onto the titanium dioxide nanofiber layer 323.

[0085] For example, the ultraviolet LED chip is an aluminum gallium nitride chip with a peak wavelength of 365nm, and the power density is stabilized at 30mW / cm² using a constant current drive circuit. 2 The chip is coupled to the end face of the quartz optical fiber 3142 via UV-curable adhesive. A hemispherical magnesium fluoride focusing lens is fused to the end of the optical fiber 3142 to focus the ultraviolet light onto the surface of the titanium dioxide nanofiber layer 323. The spot diameter is reduced from 5 mm to 1 mm, and the light intensity density is increased to 120 mW / cm². 2 (30mW / cm when not focused) 2 Actual measurements show that the technical solution of this embodiment increases the quantum efficiency of titanium dioxide from 0.8% to 2.5% (based on the toluene degradation rate), and under the condition of 40% soil moisture content, the ultraviolet transmission loss decreases from 50% to 15%, the photocatalytic reaction rate increases by 3 times, and the overall remediation cycle is shortened to 35 days.

[0086] Finally, it should be noted that in any of the aforementioned embodiments, before the device can remediate the soil, it is necessary to pre-treat the soil to be remediated by removing impurities, waste and large stones. After screening out the debris and large stones, the material is crushed using an Allu bucket to break the contaminated soil into particles smaller than 2mm as much as possible. This avoids difficulties in inserting the device into the soil, as well as the problem of excessive soil viscosity and large particle size, which could cause blockage or even damage to the biomimetic root system body 31 of the device.

[0087] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0088] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0089] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the present application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0090] For each patent, patent application, patent application publication, and other material such as articles, books, specifications, publications, and documents referenced in this application, the entire contents of that patent application are incorporated herein by reference, except for historical application documents that are inconsistent with or conflict with the content of this application, and documents that limit the broadest scope of the claims of this application (currently or subsequently appended to this application). It should be noted that if there are any inconsistencies or conflicts between the descriptions, definitions, and / or terminology used in the supplementary materials of this application and the content of this application, the descriptions, definitions, and / or terminology used in this application shall prevail.

[0091] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A bioremediation device for organically contaminated soil, characterized in that, It includes, from top to bottom, a photovoltaic electrolysis module, a mass transfer transition module, and a soil remediation module; The photovoltaic electrolysis module includes an electrolysis cell, a photovoltaic panel inclined above the electrolysis cell, and a positive electrode rod and a negative electrode rod inserted into the electrolyte. The positive electrode rod and the negative electrode rod are respectively electrically connected to the photovoltaic panel. The mass transfer transition component includes an oxygen chamber, a hydrogen chamber, and a nutrient solution chamber. The oxygen chamber and the hydrogen chamber are respectively connected to an oxygen delivery pipe and a hydrogen delivery pipe equipped with an air pump. Both the oxygen delivery pipe and the hydrogen delivery pipe extend above the liquid surface of the electrolyzer. The soil remediation component comprises a biomimetic root system body and a composite layer. The biomimetic root system body includes a support column, primary branches, and secondary branches. An oxygen pipe, a hydrogen pipe, and a cable pipe are coaxially sleeved inside the support column to form an unconnected nutrient solution channel, oxygen channel, and hydrogen channel. The first-level branch has a hydrogen flow channel, a first oxygen flow channel, and a first nutrient solution flow channel that are not interconnected, and is connected to the hydrogen channel, oxygen channel, and nutrient solution channel respectively. The second-level branch has a second oxygen flow channel and a second nutrient solution flow channel that are not interconnected, the second oxygen flow channel is connected to the first oxygen flow channel, and the second nutrient solution flow channel is connected to the first nutrient solution flow channel. The nutrient solution in the first nutrient solution flow channel, the second nutrient solution flow channel, and the nutrient solution channel can all flow into the composite layer. The composite layer covers the surface of the biomimetic root system and includes a biochar coating, a graphene conductive mesh layer, and a titanium dioxide nanofiber layer stacked from the inside out. The cable conduit contains an optical fiber with an ultraviolet LED chip and a wire connected to the negative electrode of the photovoltaic panel. The wire is provided with a corrosion-resistant conductive contact at its end extending to the soil. The optical fiber extends to the titanium dioxide nanofiber layer. The end of the primary branch is provided with a pulsed high-pressure hydrogen injection hole, and the end of the secondary branch is provided with an oxygen injection hole with a hydrophobic membrane.

2. The bioremediation device for organically contaminated soil according to claim 1, characterized in that, The aperture of the pulsed high-pressure hydrogen injection orifice is 20-50 μm, the pulse frequency is 1-5 Hz, and the contact angle of the hydrophobic membrane is >150°.

3. The bioremediation device for organically contaminated soil according to claim 1, characterized in that, The titanium dioxide nanofiber layer is doped with ferric ions or nitrogen, giving it visible light response characteristics with a response wavelength range of 400-550 nm.

4. The bioremediation device for organically contaminated soil according to claim 1, characterized in that, The surface of the support column is provided with a spiral guide groove, the pitch of which is 5-10mm and the depth is 2-5mm, which is used to enrich pollutants and guide the pollutants to migrate to the composite layer.

5. The bioremediation device for organically contaminated soil according to claim 1, characterized in that, The bifurcation angle between the primary branch and the secondary branch is 60°-80°, and the diameter of the secondary branch is 1 / 3-1 / 2 of that of the primary branch.

6. The bioremediation device for organically contaminated soil according to any one of claims 1 to 5, characterized in that, The device further includes an intelligent control unit, which comprises: A potential monitoring module is used to monitor the soil redox potential in real time and adjust the hydrogen injection pressure. The spectral analysis module controls the power of the ultraviolet LED chip by feeding back the intensity of ultraviolet light through optical fiber. The dynamic nutrient solution dispensing module adjusts the nutrient solution release rate according to the soil pH value.

7. The bioremediation device for organically contaminated soil according to claim 1, characterized in that, The corrosion-resistant conductive contact is a platinum-plated ceramic sheet or a graphene-coated electrode, and the surface roughness of the corrosion-resistant conductive contact ranges from Ra 0.8 to 1.6 μm.

8. The bioremediation device for organically contaminated soil according to claim 1, characterized in that, The organic polluted soil bioremediation device also includes a microalgae reactor, which is connected to the electrolytic cell and is used to convert the carbon dioxide generated by electrolysis into biomass and store it.

9. The bioremediation device for organically contaminated soil according to claim 1, characterized in that, The hydrogen pipe is equipped with a pulse backwash valve at its end. The backwash valve has a flushing pressure range of 0.5-0.8 MPa and a flushing frequency of once every 24 hours, lasting 10-30 seconds each time.

10. The bioremediation device for organically contaminated soil according to claim 1, characterized in that, The ultraviolet LED chip has an emission wavelength range of 360nm-370nm and a power density range of 10-50mW / cm², and the end of the optical fiber is provided with a focusing lens to focus ultraviolet light onto the titanium dioxide nanofiber layer.

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