Device for repairing organic contaminated soil through in-situ coupling photocatalysis-bioelectricity and repairing method of organic contaminated soil

Abstract

The invention provides a device for in-situ coupling photocatalysis-bioelectricity remediation of organic contaminated soil and a remediation method of the organic contaminated soil, and belongs to the technical field of soil remediation. According to the device for in-situ coupling photocatalysis-bioelectricity remediation of the organic contaminated soil, a light-emitting type anode unit wraps an illumination system, the light-emitting type anode unit comprises a carbon felt, through holes are formed in the surface of the carbon felt, and light guide optical fibers are inserted into the through holes. By integrating optical fiber light guide, photocatalytic reaction, electrode electron conduction and microbial metabolism on the anode, high-efficiency synergy of pollutant oxidation and degradation processes is realized, effective transfer of photo-induced electrons can be promoted, electron-hole recombination can be inhibited, the photocatalytic reaction efficiency can be remarkably enhanced, and the photocatalytic effect can be improved. The photocatalytic pretreatment can oxidize macromolecular pollutants into low-toxicity micromolecular intermediates, so that the bioavailability of the macromolecular pollutants is remarkably improved, and further deep degradation of microorganisms is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and in particular to a device for in-situ coupled photocatalysis-bioelectric remediation of organically contaminated soil and a method for remediating organically contaminated soil. Background Art

[0002] With the acceleration of industrialization, a large number of organic pollutants generated by industries such as petrochemicals, printing and dyeing, pesticides, and pharmaceuticals have entered the soil environment. Petroleum hydrocarbons (such as benzene, naphthalene, phenanthrene, and benzo[a]pyrene) are particularly prominent soil organic pollutants due to their strong hydrophobicity, stable structure, easy accumulation, and difficulty in degradation. These pollutants not only damage the ecological structure and function of soil but also enter the human body through the food chain, posing a potential threat to human health. Remediation technologies for organically contaminated soils are constantly evolving and currently primarily include physical methods (such as thermal desorption and solidification), chemical methods (such as redox agent addition), and biological methods (such as microbial degradation and phytoremediation). Bioremediation is considered one of the most sustainable remediation methods due to its low cost, eco-friendliness, and suitability for large-scale remediation. However, in practical applications, traditional bioremediation technologies still have significant limitations. For example, in areas of high-concentration pollution or long-standing aging pollution, factors such as a shortage of electron acceptors in the soil, insufficient numbers and activity of in situ degrading bacteria, and restricted oxygen diffusion can severely inhibit microbial metabolic activity, resulting in inefficient pollutant degradation. In addition, some organic pollutants with complex structures and large molecular weights (such as polycyclic aromatic hydrocarbons, petroleum asphalt components, etc.) have extremely low bioavailability and are difficult to be directly degraded by microorganisms.

[0003] In recent years, soil bioremediation technology has emerged. By constructing a soil microbial electrochemical system (MES), using electroactive microorganisms as catalysts and solid electrodes as electron acceptors, it achieves electron transfer and energy recovery from pollutants. This technology can promote the oxidative degradation of target pollutants while driving electron flow to generate electricity or regulating microbial metabolic pathways, alleviating the electron acceptor shortage problem in traditional bioremediation processes. However, bioremediation efficiency remains low. Summary of the Invention

[0004] In light of this, the present invention aims to provide an apparatus and method for in-situ coupled photocatalytic-bioelectric remediation of organically contaminated soil. The apparatus of the present invention can achieve synergistic coupling of photocatalytic reactions and microbial electrochemical reactions, effectively improving the in-situ degradation efficiency of high-molecular organic pollutants in soil.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides an in-situ coupled photocatalytic-bioelectric remediation device for organically contaminated soil, comprising:

[0007] A container and a "luminous" anode unit, a floating cathode, a wire connecting the "luminous" anode unit and the floating cathode, a resistor assembly, a lighting system, and a voltage collection system arranged in the container;

[0008] The outer surface of the container is provided with a light-shielding layer;

[0009] The "luminous" anode unit wraps the lighting system, and the "luminous" anode unit includes carbon felt. The surface of the carbon felt is provided with through holes, and light-guiding optical fibers (polymer light-guiding fibers) are inserted into the through holes.

[0010] Preferably, the through hole density is 0.5 to 2 holes / cm 2 .

[0011] Preferably, the carbon felt has a size of (10-50) cm×(10-50) cm and a thickness of 3-10 mm.

[0012] Preferably, the length of the light-guiding optical fiber is 0.5 to 5 cm.

[0013] Preferably, the lighting system is cylindrical, and the height of the cylinder is 5 to 50 cm and the diameter is 2 to 10 cm.

[0014] Preferably, the floating cathode is an annular carbon felt structure, and the annular carbon felt structure has an outer diameter of 6 to 20 cm, an inner diameter of 3 to 10 cm, and a thickness of 3 to 10 mm.

[0015] Preferably, the vertical distance between the "luminous" anode unit and the floating cathode is 1 to 5 cm.

[0016] Preferably, the surface of the "luminous" anode unit is wound with titanium wire to form a conductive connecting ring.

[0017] The present invention also provides a method for remediating organic contaminated soil, using the device for in-situ coupled photocatalysis-bioelectric remediation of organic contaminated soil described in the above technical solution, comprising the following steps:

[0018] Mixing contaminated soil with water and filling it into the container of the device, and then embedding the "luminous" anode unit into the contaminated soil;

[0019] adding a liquid sealing water layer, and placing the floating cathode in the liquid sealing water layer;

[0020] Connect the "luminous" anode unit and the floating cathode through a wire, then connect them to the resistor assembly, and then connect them to the voltage acquisition system;

[0021] The lighting system is started to perform repair.

[0022] Preferably, the repair voltage is 0.1-1.0V.

[0023] The present invention provides an in-situ coupled photocatalytic-bioelectric remediation device for organically contaminated soil, comprising: a container and a "luminescent" anode unit arranged in the container, a floating cathode, a wire connecting the "luminescent" anode unit and the floating cathode, a resistor component, a lighting system and a voltage collection system; the outer surface of the container is provided with a light-shielding layer; the "luminescent" anode unit wraps the lighting system, and the "luminescent" anode unit includes carbon felt, the surface of the carbon felt is provided with a through hole, and a light-guiding optical fiber is inserted into the through hole.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] Photocatalytic technology has attracted attention due to its ability to efficiently generate reactive oxygen species and induce the initial breakage and oxidation of pollutants. Various potential photosensitive substances naturally present in the soil, such as semiconductor minerals (such as Fe2O3, TiO2), natural pigments, humic acid substances, etc., can excite electron-hole pairs (e - / h + ), further generating hydroxyl radicals (·OH), superoxide anion radicals (O2· - ) and other highly active free radicals. These free radicals can non-selectively attack refractory organic pollutants, achieving initial cracking of the pollutant structure and mitigation of toxicity, thereby improving the bioavailability of pollutants and providing a good pre-treatment basis for subsequent microbial degradation. The present invention couples photocatalysis with bioelectric remediation technology to form a "photocatalytic-bioelectric" synergistic remediation system with significant synergistic efficiency potential. The photocatalytic reaction provides primary oxidation capacity, enhancing the degradability of pollutants, while the bioelectric system achieves deep degradation of pollutants by promoting electron transfer and maintaining the activity of electroactive bacterial communities. This synergistic mechanism is expected to promote pollutants from high-molecular-weight toxic compounds to small-molecule intermediate metabolites, and then ultimately mineralize into inorganic substances such as carbon dioxide and water, realizing the full-process degradation and transformation of pollutants, and achieving the purpose of efficient, green, in-situ remediation of soil pollution.

[0026] The present invention is based on the construction of a soil photocatalytic-bioelectric synergistic remediation system, integrating natural photocatalysts, electroactive microorganisms and light-guiding optical fibers, to solve the problems existing in the existing soil organic pollution remediation, such as low bioavailability of pollutants, poor electron transfer efficiency, and long remediation cycle, and improves the in situ degradation efficiency of persistent organic pollutants in the soil (such as aromatic hydrocarbons, petroleum pollutants, etc.). The "luminescent" anode unit organically integrates the light-guiding optical fiber and the electrode material for the first time, realizing the synergistic effect of photocatalysis and bioelectricity on the same reaction interface in the contaminated soil, greatly improving the initial oxidation activity and microbial degradability of the pollutants; the device of the present invention is a photocatalytic-bioelectric combined remediation device with a reasonable structure and integrated functions, suitable for on-site in situ remediation, aiming to break through the bottleneck of a single technology, construct a synergistic remediation system that can operate stably under actual site conditions, and significantly improve the remediation efficiency and operability of soil organic pollutants, with important theoretical value and application prospects.

[0027] The present invention also provides a method for remediating organically contaminated soil, in which the photons are precisely guided to the soil-electrode interface through the "luminescent" anode unit, thereby achieving synergistic coupling of photocatalytic reaction and microbial electrochemical reaction, and effectively improving the in situ degradation efficiency of high-molecular organic pollutants in the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of the "luminescent" anode unit and the "luminescent" anode of Example 1;

[0029] Figure 2 This is a schematic structural diagram of the device for in-situ coupled photocatalysis-bioelectric remediation of organically contaminated soil according to Example 1;

[0030] Figure 3 The fluctuation of biovoltage generated by the in-situ coupled photocatalytic-bioelectric remediation device for organically contaminated soil degradation in Example 1 is shown;

[0031] Figure 4 This is the device for in-situ coupled photocatalysis-bioelectric remediation of organically contaminated soil in Example 1 and the changes in total solid organic carbon in Comparative Example 1. DETAILED DESCRIPTION

[0032] The present invention provides an in-situ coupled photocatalytic-bioelectric remediation device for organically contaminated soil, comprising:

[0033] A container and a "luminous" anode unit, a floating cathode, a wire connecting the "luminous" anode unit and the floating cathode, a resistor assembly, a lighting system, and a voltage collection system arranged in the container;

[0034] The outer surface of the container is provided with a light-shielding layer;

[0035] The "luminous" anode unit wraps the lighting system, and the "luminous" anode unit includes carbon felt. The surface of the carbon felt is provided with a through hole, and a light-guiding optical fiber is inserted into the through hole.

[0036] In the present invention, the light-guiding optical fiber passes through the carbon felt.

[0037] The present invention integrates light-guiding optical fiber, photocatalytic reaction, electrode electron conduction and microbial metabolism (using external potential to drive the enrichment of electroactive microorganisms on the surface and surrounding of the "luminescent" anode unit, and the electroactive microorganisms and other functional bacteria (such as degrading bacteria) can synergistically metabolize organic pollutants) in the anode area, thereby achieving efficient synergy of pollutant oxidation and degradation processes, promoting the effective transfer of photogenerated electrons, inhibiting electron-hole recombination, and significantly enhancing the efficiency of the photocatalytic reaction. Photocatalytic pretreatment can oxidize large molecular pollutants into small molecular intermediates with lower toxicity, significantly improving their bioavailability, and promoting further deep degradation by microorganisms; the device is suitable for various types of organically contaminated soils, has in-situ application capabilities and good engineering scalability; in addition, the device can be driven by solar energy or low-power LED light sources, has low operating energy consumption, is environmentally friendly, and conforms to the concepts of green, low-carbon and sustainable development. In summary, the present invention constructs a soil photocatalytic-bioelectric synergistic remediation system based on a "luminescent" anode unit, which for the first time realizes the organic coupling of light, electricity, and microorganisms in the same in situ system, significantly improving the in situ degradation efficiency of high-molecular organic pollutants (such as aromatic hydrocarbons and petroleum hydrocarbons), and has important environmental application value and promotion prospects.

[0038] In the present invention, the “luminous” anode unit and the lighting system constitute a “luminous” anode.

[0039] In the present invention, the "luminous" anode unit includes a carbon felt, a surface of the carbon felt is provided with a through hole, and a light-guiding optical fiber is inserted into the through hole.

[0040] In the present invention, the hole density of the through holes is preferably 0.5 to 2 holes / cm 2 , specifically 0.5, 1, 1.5 or 2 pores / cm 2 .

[0041] In the present invention, the size of the carbon felt is preferably (10-50) cm×(10-50) cm, more preferably 10 cm×10 cm, and the thickness is preferably 3-10 mm, specifically 3, 4, 5, 6, 7, 8, 9 or 10 mm.

[0042] In the present invention, the through holes are evenly arranged on the surface of the carbon felt.

[0043] In the present invention, the length of the light-guiding optical fiber is preferably 0.5 to 5 cm, specifically 0.5, 1, 2, 3, 4 or 5 cm.

[0044] In the present invention, the lighting system is preferably cylindrical, the height of the cylinder is preferably 5 to 50 cm, specifically 5, 10, 15, 20, 30, 40 or 50 cm, and the diameter is preferably 2 to 10 cm, specifically 2, 3, 4, 5, 6, 7, 8, 9 or 10 cm.

[0045] In the present invention, the lighting system is preferably a 360° luminous LED light source, and the lighting system preferably emits ultraviolet light (wavelength 200-400nm), visible light (wavelength 400-700nm) or near-infrared light (wavelength 700-1000nm) to simulate different solar radiation conditions. The LED light source has low energy consumption and is environmentally friendly, which is in line with the concepts of green, low-carbon and sustainable development.

[0046] In the present invention, the surface of the "luminous" anode unit is preferably wound with titanium wire to form a conductive connecting ring for connecting with the resistor component or voltage acquisition system to form a closed circuit.

[0047] In the present invention, the extended length of the conductive connecting ring is preferably 5 to 10 cm, specifically 5, 6, 7, 8, 9 or 10 cm.

[0048] In the present invention, the conductive connecting ring is preferably arranged in the middle of the "luminous" anode unit, which can improve the ability of the titanium wire to absorb electrons from the carbon felt, reduce resistance, distribute current evenly, and make the conductive effect more stable.

[0049] In the present invention, the floating cathode is preferably an annular carbon felt structure, the outer diameter of the annular carbon felt structure is preferably 6 to 20 cm, specifically 6, 8, 10, 15 or 20 cm, the inner diameter is preferably 3 to 10 cm, specifically 3, 4, 5, 6, 7, 8, 9 or 10 cm, and the thickness is preferably 3 to 10 mm, specifically 3, 4, 5, 6, 7, 8, 9 or 10 mm.

[0050] In the present invention, the floating cathode is preferably placed in a covering water layer, and the distance between the anode and cathode is adjusted by adjusting the height of the covering water layer.

[0051] In the present invention, the vertical distance between the "luminous" anode unit and the floating cathode is preferably 1 to 5 cm, specifically 1, 2, 3, 4 or 5 cm.

[0052] In the present invention, the container is preferably a cylinder made of acrylic material, the height of the container is preferably 10 to 60 cm, specifically 10, 20, 30, 40, 50 or 60 cm, the diameter is preferably 8 to 100 cm, specifically 8, 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100 cm, and a liquid guide hole is provided at the bottom of the container for repeated use and sample extraction.

[0053] In the present invention, the material of the light-shielding layer is preferably aluminum foil or tin foil.

[0054] In the present invention, the "luminous" anode unit is connected to the floating cathode through a wire, and then preferably connected to the resistor component, and then connected to the voltage acquisition system to form a stable closed-circuit system, which can continuously record voltage changes during system operation.

[0055] In the present invention, the resistance of the resistor component is preferably 1000±200Ω.

[0056] The present invention has no particular limitation on the preparation method of the device for in-situ coupled photocatalysis-bioelectric remediation of organically contaminated soil, and any assembly method familiar to those skilled in the art may be used.

[0057] In the present invention, the carbon felt is preferably pretreated with acetone. The acetone pretreatment is used to remove impurities and oil stains in the carbon felt, improve surface cleanliness, and enhance electrical conductivity and microbial attachment ability.

[0058] After the acetone pretreatment is completed, the mixture is preferably washed with ethanol and distilled water in sequence and dried for later use.

[0059] The present invention also provides a method for remediating organic contaminated soil, using the device for in-situ coupled photocatalysis-bioelectric remediation of organic contaminated soil described in the above technical solution, comprising the following steps:

[0060] Mixing contaminated soil with water and filling it into the container of the device, and then embedding the "luminous" anode unit into the contaminated soil;

[0061] adding a liquid sealing water layer, and placing the floating cathode in the liquid sealing water layer;

[0062] Connect the "luminous" anode unit and the floating cathode through a wire, then connect them to the resistor assembly, and then connect them to the voltage acquisition system;

[0063] The lighting system is started to perform repair.

[0064] The present invention mixes contaminated soil with water and fills the mixture into the container of the device, and then embeds the "luminous" anode unit into the contaminated soil.

[0065] In the present invention, the contaminated soil is preferably taken from an actual contaminated farmland or oil field area. The contaminated soil is preferably air-dried and then sieved, and the particle size is preferably no greater than 2 mm.

[0066] In the present invention, the filling height of the contaminated soil is preferably 5 to 50 cm, specifically 5, 12, 20, 30, 40 or 50 cm, and the moisture content is preferably 15 to 30%, specifically 15%, 20%, 25% or 30%.

[0067] After the "luminous" anode unit is embedded, the present invention adds a liquid sealing water layer, and places the floating cathode in the liquid sealing water layer.

[0068] In the present invention, it is preferred to set the wavelength and illumination period of the illumination system, regularly monitor the system output voltage and the content of organic pollutants in the soil, evaluate the remediation effect, and replace the light source type or adjust the illumination intensity as needed to optimize the remediation effect.

[0069] In the present invention, the photoperiod is set to 8 to 16 hours per day, and the duration is preferably 10 to 60 days.

[0070] In the present invention, closed-circuit treatment groups with different wavelength light source conditions (such as ultraviolet, visible light, and near-infrared) and open-circuit control groups can be set to clarify the effects of different light sources on pollutant degradation efficiency and microbial electron transfer capacity.

[0071] In the present invention, the repair voltage is preferably 0.1 to 1.0 V, specifically 0.1, 0.5 or 1.0 V, which serves as a reference indicator of bioelectric activity and pollutant degradation rate.

[0072] In the present invention, the repair temperature is preferably 20-30°C to ensure microbial activity.

[0073] To address the problems of poor bioavailability of pollutants, low electron transfer efficiency, and long remediation cycles in organically contaminated soil, the present invention proposes an in-situ device and method for coupled photocatalytic-bioelectric remediation, aiming to enhance pollutant oxidation activity, strengthen microbial metabolism, and achieve photo-electro-microbial synergistic remediation. This system, based on a "luminescent" anode unit, demonstrates the following advantages for in-situ remediation of persistent organic pollutants (such as aromatic hydrocarbons and petroleum compounds):

[0074] First, innovative photocatalytic-microbial electrochemical synergistic remediation improves remediation efficiency. This invention utilizes optical fibers to precisely direct light energy into the anode region. By integrating natural photocatalysts and conductive materials, photocatalytic oxidation of pollutants and subsequent microbial electrochemical degradation at the electrode interface is achieved, significantly increasing the cracking rate and microbial degradability of high-molecular organic pollutants, breaking the bottlenecks of efficiency and reaction depth in traditional single remediation technologies.

[0075] Second, it effectively enhances the electron transfer process and improves the utilization rate of photogenerated electrons. By organically integrating light-guiding optical fibers, photocatalysts, and anode electrode materials (carbon felt), this invention constructs a highly efficient electron transfer pathway, effectively inhibiting the recombination of photogenerated electron-hole pairs, significantly improving the efficiency of the photocatalytic reaction, and further enhancing the electron energy-harvesting ability of microorganisms, which is conducive to driving efficient microbial metabolism and thorough mineralization of pollutants.

[0076] Third, it has wide applicability and good engineering scalability. The device has a simple structure, flexible operation, and can be coupled with light sources such as solar energy or low-power LEDs. It has good environmental adaptability and low energy consumption, making it suitable for in-situ remediation of various types of organically contaminated soils, especially for deep treatment of refractory organic pollution.

[0077] Fourth, it complies with the concept of green, low-carbon, and sustainable development. The materials used in this invention are safe and environmentally friendly, requiring no external high-energy-consuming equipment or toxic chemicals. There is no risk of secondary pollution during the repair process. The system consumes low energy and can operate stably over the long term, making it highly environmentally friendly and promising for widespread application.

[0078] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0079] Example 1

[0080] Figure 1 Schematic diagram of the structure of the "luminous" anode unit and the "luminous" anode in Example 1, Figure 2 This is a schematic structural diagram of the device for in-situ coupled photocatalysis-bioelectric remediation of organically contaminated soil in Example 1.

[0081] Assembly of the "luminous" anode

[0082] Cut a 10cm×10cm carbon felt (5mm thickness), soak it in acetone overnight, wash it three times with ethanol and distilled water, and dry it for later use. Use a steel cone to evenly punch through holes on the prepared carbon felt at a density of 1 hole / cm2 . Select a soft, light-conducting polymer as the light-guiding optical fiber (2mm in diameter), cut it into several short rods of 1cm in length, and insert them into the through-holes of the carbon felt. Customize a cylindrical LED lamp tube with a diameter of 3cm and a length of 15cm, which can emit 360-degree light (including ultraviolet, visible light, and near-infrared). Wrap the carbon felt inserted into the optical fiber and fix it around the lamp tube so that the light source can propagate outward along the optical fiber. Wrap a titanium wire (1mm in diameter) around the middle of the carbon felt electrode and extend it upward, exposing 5cm from the upper surface of the carbon felt for connecting to the external wire. The prepared "luminous" anode is ready for use.

[0083] Construction of an in situ coupled photocatalytic-bioelectric remediation device for organically contaminated soil

[0084] A cylindrical acrylic box with a diameter of 10 cm and a height of 20 cm was used as the container. Petroleum hydrocarbons were used as a representative example of recalcitrant organic pollutants in soil. Petroleum-contaminated soil was collected from the 0-10 cm surface layer around the beam pumping units in the Dagang Oilfield, Tianjin. The soil was air-dried in a cool, well-ventilated environment, and grit and plant debris were removed before grinding through a 2 mm sieve. 1000 g of the petroleum-contaminated soil was weighed and mixed with 300 mL of distilled water. A prepared "luminous" anode was placed in the center of the container. The mixed petroleum-contaminated soil was then layered into the reactor and compacted. Once the contaminated soil reached a height of 12 cm, 100 mL of distilled water was added for liquid sealing, forming a 1.5 cm overlying water layer. A floating cathode was used. A circular ring of carbon felt (5 mm thick) with an outer diameter of 8 cm and an inner diameter of 4 cm was cut and fixed to the center of the overlying water layer using titanium wire. After the electrode was installed, the reactor was tightly wrapped with tin foil to protect it from light. The floating cathode and the "luminescent" anode were connected with a 1000Ω external resistor assembly, and the voltage was recorded once a minute using a PISO-813U voltage acquisition card, with the average value recorded every 30 minutes. The treatment groups using ultraviolet, visible light, and near-infrared LED light sources were labeled CCB, CCW, and CCR, respectively, and intermittent lighting was applied for 12 hours to simulate actual conditions.

[0085] Determination of repair effect

[0086] In the constructed in situ coupled photocatalytic-bioelectric soil remediation system, the functional microorganisms with electroactive microorganisms as the core can metabolize organic pollutants in the soil while generating biovoltage. Therefore, the consumption of petroleum hydrocarbons in the soil can be reflected by collecting the value of biovoltage. When the pollutant consumption efficiency is high, the electron release rate is large, which is manifested as an increase in the system output voltage or maintaining a high level. As the concentration of petroleum hydrocarbons gradually decreases, the electron donor decreases and the biovoltage gradually decreases. After the remediation is completed, the total organic carbon (SOC) content in the soil is detected using a total organic carbon analyzer to further verify the removal effect of petroleum hydrocarbon pollutants. The specific operation includes: taking representative soil samples from each reactor, freeze-drying, grinding and sieving, acidifying and then measuring the SOC according to the instrument operating procedures.

[0087] Comparative Example 1

[0088] The same as Example 1, the only difference is that no light guide fiber is introduced, and the operating conditions are consistent with Example 1. This group is marked as CK.

[0089] Test Example 1

[0090] Fluctuations in biovoltage of the constructed in-situ coupled photocatalytic-bioelectric soil remediation system:

[0091] Under 12-hour intermittent illumination, the changes in biovoltage of each group were recorded. In the early stage of the experiment (0-6 days), as the electroactive microorganisms gradually enriched and the concentration of organic pollutants in the soil continued to be consumed, the voltage of all reactors showed an overall upward trend. Under visible light and ultraviolet light conditions, the output voltage of the repair system was significantly higher than that of the control group without light source, indicating that the external light source significantly enhanced the electron transfer efficiency of the system ( Figure 3 ). After running for 6 days, the voltage of the control group entered a plateau period and remained relatively stable (55mV), while the treatment groups stimulated by light still maintained a relatively high voltage level, and were significantly higher than the control group (visible light 127mV, ultraviolet light 119mV), and increased by 131% and 115% respectively compared with the control group, indicating that the photocatalytic-bioelectric coupling process has a continuous contribution to improving the activity of the system. In addition, under the action of 12h intermittent illumination, the voltage of the reactor in the treatment group showed a periodic fluctuation characteristic that was highly consistent with the illumination cycle, and there were differences in the voltage response amplitude under excitation of light sources of different wavelengths, which further verified the effect of illumination wavelength on the strengthening effect of the composite repair system. These results collectively show that the coupled photocatalytic process not only improves the overall electron transfer ability of the system, but also gives it the ability to dynamically respond to the external light environment, providing a theoretical basis for the construction of efficient and controllable in situ repair technology.

[0092] Test Example 2

[0093] Changes in total solid organic carbon:

[0094] The results showed that compared with the control group CK (SOC was 77.96 mg / g), all photocatalytic-bioelectric treatment groups showed significant organic carbon removal effects ( Figure 4 ). Among them, the ultraviolet light group (CCB) had the lowest SOC of 65.45 mg / g, with a removal rate of 16.0%, indicating that short-wave high-energy light sources can significantly stimulate the active sites on the catalyst surface and promote the oxidative decomposition of pollutants; followed by the near-infrared light group (CCR) and the visible light group (CCW), with SOCs of 68.01 mg / g and 69.10 mg / g, respectively, and removal rates of 12.8% and 11.4%, respectively. The petroleum-contaminated soil used in this test case is aged soil formed by years of natural exposure. Its pollutant components have strong adhesion and poor biodegradability, making it difficult to treat. Despite this, each treatment group still showed significant pollutant removal ability, verifying the high efficiency degradation potential of this device for aged petroleum hydrocarbon pollutants. In addition, the standard error of SOC between treatment groups was small (<1.5 mg / g), indicating good experimental repeatability. Comprehensive analysis shows that coupled photocatalysis significantly improves the metabolic efficiency of functional bacterial communities such as electroactive microorganisms for petroleum hydrocarbon pollutants, and different wavelength light sources have different effects on the degradation performance of the system, among which ultraviolet light has the best effect. This result is consistent with the voltage response trend, further verifying the enhanced mechanism of the composite remediation system in pollutant removal.

[0095] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A device for in-situ coupled photocatalysis-bioelectric remediation of organically contaminated soil, characterized in that: include: A container and a "luminous" anode unit, a floating cathode, a wire connecting the "luminous" anode unit and the floating cathode, a resistor assembly, a lighting system, and a voltage collection system arranged in the container; The outer surface of the container is provided with a light-shielding layer; The "luminous" anode unit wraps the lighting system, and the "luminous" anode unit includes carbon felt. The surface of the carbon felt is provided with a through hole, and a light-guiding optical fiber is inserted into the through hole.

2. The device according to claim 1, characterized in that The through hole density is 0.5 to 2 holes / cm 2 .

3. The device according to claim 1, characterized in that The carbon felt has a size of (10-50) cm×(10-50) cm and a thickness of 3-10 mm.

4. The device according to claim 1 or 3, characterized in that The length of the light-guiding optical fiber is 0.5 to 5 cm.

5. The device according to claim 1, characterized in that The lighting system is cylindrical, and the height of the cylinder is 5 to 50 cm and the diameter is 2 to 10 cm.

6. The device according to claim 1, characterized in that The floating cathode is an annular carbon felt structure with an outer diameter of 6 to 20 cm, an inner diameter of 3 to 10 cm, and a thickness of 3 to 10 mm.

7. The device according to claim 1 or 6, characterized in that The vertical distance between the "luminous" anode unit and the floating cathode is 1 to 5 cm.

8. The device according to claim 1, characterized in that The surface of the "luminous" anode unit is wound with titanium wire to form a conductive connecting ring.

9. A method for remediating organically contaminated soil, characterized in that: The device for in-situ coupled photocatalysis-bioelectric remediation of organically contaminated soil according to any one of claims 1 to 8 comprises the following steps: Mixing contaminated soil with water and filling it into the container of the device, and then embedding the "luminous" anode unit into the contaminated soil; adding a liquid sealing water layer, and placing the floating cathode in the liquid sealing water layer; Connect the "luminous" anode unit and the floating cathode through a wire, then connect them to the resistor assembly, and then connect them to the voltage acquisition system; The lighting system is started to perform repair.

10. The repair method according to claim 9, characterized in that: The repair voltage is 0.1-1.0V.

Images