Simulation test system and simulation test method for process of phytoremediation of chlorinated hydrocarbon pollutants

Abstract

The invention discloses a simulation test system and a simulation test method for a process of phytoremediation of chlorinated hydrocarbon pollutants, the simulation test system comprises a plant experiment box, a water supply system, a monitoring assembly, a liquid recovery bottle and an imaging system, the water supply system, the plant experiment box and the liquid recovery bottle are sequentially connected in series through a hose; the imaging system consists of a lighting lamp box, a camera and a computer; the plant experiment box is used as a main body, so that the influence of plants on the distribution of pollutants in a porous medium in different growth environments can be flexibly simulated, and the change of physicochemical property parameters around a root system can be monitored in real time; by tracking the change of the distribution condition of pollutants in a two-dimensional system, the pollutant removal process of phytoremediation is studied, and the removal effect and action mechanism of different plant growth regulation and control technologies, solubilization strengthening technologies and the like on organic pollutants of plants in a simulated porous medium are verified.

Description

Technical Field

[0001] This invention relates to the field of environmental engineering technology, specifically to a simulation test system and method for the phytoremediation of chlorinated hydrocarbon pollutants. Background Technology

[0002] Chlorinated organic compounds (COCs) are important chemical raw materials, characterized by their volatility and carcinogenic, teratogenic, and mutagenic properties. They can harm human health after entering the body through various exposure routes. Chlorinated hydrocarbon pollutants are commonly used as organic solvents, chemical raw materials and intermediates, flame retardants and fireproofing materials, organochlorine pesticides, and fumigants in industries such as industry, agriculture, medicine, and daily chemicals. They are also a common site pollutant in industrial parks. Chlorinated COCs are highly hydrophobic, poorly soluble in water, and denser than water. Once in a site, they adsorb onto the surface of soil solid particles or migrate into deeper soil layers, entering aquifers or groundwater. Because chlorinated COCs are difficult to degrade in the natural environment, they often remain in the environment for extended periods, continuously posing ecological and environmental risks.

[0003] As my country's campaign to protect clean soil continues, at the end of 2023, the Ministry of Ecology and Environment issued the "Guiding Opinions on Promoting Soil Pollution Risk Management and Green Low-Carbon Remediation," clarifying the overall prevention and control strategy of synergistic effect in pollution reduction and carbon reduction, and encouraging the comprehensive use of both natural restoration and artificial remediation to promote soil pollution risk management and green low-carbon remediation. Phytoremediation is generally considered an environmentally friendly and low-cost means of pollutant removal. Some plants can absorb, transform, fix, or degrade pollutants in the soil during their growth, thereby reducing the ecological and environmental risks of pollutants. In addition, plants also have the benefits of carbon sequestration and emission reduction, as well as the function of greening the landscape. Developing phytoremediation technology is a relatively ideal choice for the transformation of soil pollution risk management and green low-carbon remediation.

[0004] In phytoremediation, considerable research has been conducted on the use of plants to treat heavy metal pollution. For example, *Centipeda minima* is used to remove arsenic pollutants from soil, and *Sedum aizoon* can effectively alleviate cadmium pollution in soil. The technology of applying these plants to the remediation of heavy metals in soil is relatively mature and is being gradually promoted and applied. Regarding organic pollutants (polycyclic aromatic hydrocarbons, chlorinated hydrocarbons, etc.), tall fescue (…) has been screened and selected… Festuca arundinacea ), ryegrass ( Lolium perenne L.), alfalfa ( Medicago sativa L.), Sudan grass ( Sorghum vulgarePhytophthora (L.) and other grasses have been used in phytoremediation, and numerous cultivation experiments have confirmed their effectiveness in removing organic pollutants. However, overall, their remediation efficiency is limited, and their application in actual site remediation is relatively rare. On the one hand, compared to physical or chemical remediation techniques, the slow growth of plants directly limits the pollutant removal rate. On the other hand, the ability of plants to remove pollutants is influenced by multiple factors, including the effectiveness of the interaction between plant roots and pollutants, and the activity of rhizosphere microorganisms. Therefore, further research and exploration are needed to promote the application of phytoremediation technology.

[0005] The key to phytoremediation of organic pollutants lies in the role of the root system. Plant roots accumulate, volatilize, or metabolically degrade organic pollutants in soil and groundwater. Additionally, plants can stimulate the growth of surrounding organisms through root exudates, enabling microbial action to remove organic pollutants from the environment. Currently, the commonly used methods for studying phytoremediation of organic pollutants include pot experiments or simulated incubators, conducting soil culture experiments under controlled conditions. However, soil structure and composition are complex and highly heterogeneous, thus presenting limitations in terms of experimental scale, operability, visualization, and pollutant distribution. Furthermore, the processes and mechanisms of phytoremediation of organic pollutants require further in-depth research.

[0006] Therefore, it is necessary to establish a simulation system and method that can intuitively reflect the relationship between plant root function and pollutant degradation, so as to provide a solid experimental guarantee for exploring phytoremediation mechanisms and optimizing phytoremediation regulation measures. Summary of the Invention

[0007] The purpose of this invention is to provide a simulation test system and method that is appropriately scaled, highly operable, and can reflect the influence of root activity on the distribution of organic pollutants in porous media during the remediation process of plants. This system is used to explore the mechanism of action of plants in remediating chlorinated organic compounds and to develop and optimize phytoremediation regulation measures, thereby solving the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A simulation experimental system for phytoremediation of chlorinated hydrocarbon pollutants includes a plant experimental chamber, a water supply system, a monitoring component, a liquid recovery bottle, and an imaging system. The water supply system, the plant experimental chamber, and the liquid recovery bottle are connected in series via flexible hoses. The imaging system consists of a lighting box, a camera, and a computer. The lighting box and the camera are respectively placed on both sides of the plant experimental chamber.

[0009] As a further aspect of the present invention: the plant experiment box is composed of a U-shaped frame, transparent tempered glass, partitions and braked casters. Transparent tempered glass is placed on both the front and rear sides of the U-shaped frame. Square grooves are opened on the upper part of the side walls of the U-shaped frame. The side walls of the plant experiment box are provided with circular water inlets and outlets of different heights, and the water inlets and outlets on both side walls are at the same height.

[0010] As a further embodiment of the present invention: the water supply system consists of a liquid storage bottle, a micro-nano bubble generator and a peristaltic pump. The liquid storage bottle, the micro-nano bubble generator and the peristaltic pump are connected in series via a hose, and the water outlet of the peristaltic pump is connected to the water inlet of the plant experimental box via a hose.

[0011] As a further embodiment of the present invention: the monitoring component includes a dissolved oxygen sensor, a redox potential sensor, a pH sensor, etc. The sensors in the monitoring component are vertically inserted into the plant experimental box, and the sensors are connected to the corresponding sensor instruments through data cables.

[0012] As a further embodiment of the present invention: the liquid recovery bottle is connected to the water outlet of the plant experiment box via a hose.

[0013] As a further embodiment of the present invention: circular holes are made on both sides of the plant experiment box at approximately 1 / 4, 1 / 2, and 3 / 4 of the distance from the top. The circular holes on both sides of the plant experiment box are at the same height. The circular holes are connected inside and outside by PVC pipes. The connection between the circular holes and the PVC pipes is fixed and sealed with glue. Square transparent tempered glass is placed on the front and back sides of the U-shaped frame as viewing windows. The partition is detachable and is placed in a square groove.

[0014] As a further embodiment of the present invention: the PVC pipe is wrapped with a 100-300 mesh stainless steel mesh on the inner end of the plant experiment box, and the PVC pipe is connected to a control valve on the outer side of the plant experiment box.

[0015] A simulation test method for the phytoremediation process of chlorinated hydrocarbon pollutants, the method steps are as follows: Step 1: Prepare plant growth culture solution. Prepare Hoagland inorganic salt nutrient solution to simulate the plant rhizosphere growth environment and adjust the pH to 7.0. Also prepare a 10-400 mg / L carbon source solution. Step 2: Filling the simulated medium: Connect the water supply system, plant experiment box, and liquid recovery bottle in sequence. Pour water into the plant experiment box to test the airtightness of the device. After the check is completed, fill the plant experiment box with clean quartz sand. First, fill the box with 70-80 mesh quartz sand to a height of 2-3 cm. Then, according to the experimental requirements, fill the box with quartz sand particles of appropriate size (10-70 mesh). The final filling height of the quartz sand should be about 3-5 cm lower than the top of the plant experiment box. Step 3: Install the monitoring components: When the quartz sand is filled to about 1 / 2 of the height of the experimental chamber, insert the sensor vertically into the solid medium, with the sensor position close to the water outlet of the plant experimental chamber. At the same time, continue to fill the plant experimental chamber with quartz sand and other media to ensure that the sensor in the monitoring components is stable in the experimental device system. Step 4: Establish a simulated environment: Open the control valve of the inlet of the plant experiment chamber, and continuously inject the plant growth simulation solution into the plant experiment chamber at an injection rate of 0.5 mL / min-3.0 mL / min using a peristaltic pump until the plant experiment chamber is full of solution. Monitor the redox potential and dissolved oxygen in the plant experiment chamber. After running the system for 1-2 days, the readings of the pH sensor, redox potential sensor, and other components to be monitored will stabilize. Step 5: Injecting contaminants: Add an appropriate amount of indicator or tracer to the chlorinated hydrocarbon solution. The indicator or tracer is Oil Red O. Then, inject 1-7 mL of chlorinated hydrocarbon contaminants into the plant experiment chamber using a syringe. Let it stand for more than 24 hours to allow the distribution of chlorinated hydrocarbon contaminants in the plant experiment chamber to stabilize. Step 6: Plant the restoration plants. Rinse the restoration plant seeds with deionized water 5-6 times in advance, and then soak them in deionized water overnight (12h). Wrap the partition 1b with gauze (1-2 layers) and place it in the square groove of the plant experiment box. Place the soaked plant seeds on top of the gauze. The experimental system can be placed in a dark room and the required light environment can be simulated by plant growth lamps. Step 7: After the plants have grown normally, according to the specific experimental objectives, use the above experimental system to simulate the process of phytoremediation of chlorinated hydrocarbon pollutants. Maintain the room temperature at 15-30℃ and run for 20-60 days. Monitor parameters such as redox potential and dissolved oxygen in the plant experimental chamber every 2-5 days. Turn on the lighting box in the imaging system every 5-10 days. Place the camera 20-50 cm in front of the center of the plant experimental chamber (the camera's shooting range must cover the viewing window area of ​​the plant experimental chamber). The lighting box has a power of 9W-45W and is placed directly behind the plant experimental chamber, parallel to it and 15-50 cm away. The light should be perpendicular to the viewing window of the plant experimental chamber. After the simulation experiment begins, fix the relative distance between the lighting box, camera, and plant experimental chamber to ensure that the shooting angle is the same each time.

[0016] Step 8: After completing the plant growth culture, the culture solution in the plant experiment box can be replaced with a 0.01%-0.5% methylene blue solution through the water supply system. Let it stand for 3-10 minutes to stain the plant roots. Then replace the solution in the plant experiment box with deionized water until it is clear, and use a camera to record the distribution of the plant roots.

[0017] Step 9: Import the photos taken by the camera into the computer for processing (such as Matlab software), extract the brightness of specific color channels of the image, perform pixel extraction, data analysis and other related work, analyze parameters such as in-situ dissolved oxygen and redox potential in the rhizosphere during plant growth, and at the same time analyze the distribution of plant roots and chlorinated hydrocarbon pollutants in porous media to explore the mechanism of phytoremediation of organic pollutants.

[0018] As a further embodiment of the present invention: the chlorinated hydrocarbon pollutant in step five is a chlorinated hydrocarbon compound such as tetrachloroethylene, chlorobenzene, 1,2-dichloroethane, and 1,2-dichlorobenzene.

[0019] As a further embodiment of the present invention: the plants used for restoration in step six are carpet grass, Sudan grass, ryegrass, or alfalfa.

[0020] Compared with the prior art, the beneficial effects of the present invention are: This invention combines plant hydroponics with pollutant distribution simulation technology. At a suitable experimental scale, by controlling the cultivation conditions such as plant growth nutrition and light, a visual simulation device and method for the removal of organic pollutants by plant roots are constructed. Based on a simulation system, this invention can study the root system effects of various remediation and regulation measures, such as the ratio of plant growth nutrients, dissolved oxygen, and solubilizing materials, on the remediation of organic pollutants by plants. This will help to further explore the mechanisms and develop regulatory measures for the remediation of organic pollutants by plants.

[0021] This invention is flexible in design, highly operable, and applicable to a variety of different scenarios and cultivation environments. It is also convenient for maintenance and management. In addition, the simulation system has low manufacturing and operating costs and has good application and promotion value.

[0022] This invention uses a plant experiment chamber as the main body, which can flexibly simulate the influence of plants on the distribution of pollutants in porous media under different growth environments, monitor the changes in physicochemical properties around the root system in real time, and study the process of phytoremediation to remove pollutants by tracking the distribution of pollutants in a two-dimensional system. It also verifies the effects and mechanisms of different plant growth regulation technologies and solubilization enhancement technologies on the removal of organic pollutants by plants in simulated porous media. Attached Figure Description

[0023] Figure 1 A schematic diagram of the overall experimental system for simulating the process of phytoremediation of chlorinated hydrocarbon pollutants.

[0024] Figure 2 A schematic diagram of the front structure of the plant experimental chamber in a simulation experimental system for the phytoremediation of chlorinated hydrocarbon pollutants.

[0025] Figure 3A schematic diagram of the partition structure in a simulation test system for the phytoremediation of chlorinated hydrocarbon pollutants.

[0026] The diagram shows: 1-Plant experimental box, 1a-U-shaped frame, 1b-Partition, 1c-Brake caster, 1d-Square trough, 1e-Water inlet, 1f-Water outlet, 1g-Control valve, 1h-Circular hole, 1i-Transparent tempered glass, 2-Water supply system, 3-Monitoring components, 4-Liquid recovery bottle, 5-Lighting box, 6-Imaging system, 7-Storage bottle, 8-Nano bubble generator, 9-Peristaltic pump, 10-Computer, 11-Camera. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Please see Figures 1-3 In this embodiment of the invention, a simulation experimental system for the phytoremediation of chlorinated hydrocarbon pollutants includes a plant experimental chamber 1, a water supply system 2, a monitoring component 3, a liquid recovery bottle 4, and an imaging system 6. The water supply system 2, the plant experimental chamber 1, and the liquid recovery bottle 4 are connected in series via flexible tubing. The imaging system 6 consists of a lighting box 5, a camera 11, and a computer 10. The lighting box 5 and the camera 11 are respectively placed on both sides of the plant experimental chamber 1. The interior of the plant experimental chamber 1 is used to simulate the process of chlorinated hydrocarbons in porous structures. The distribution and planting of highly efficient remediation plants in the medium; the plant experimental box 1 is composed of a U-shaped frame 1a, transparent tempered glass 1i, partition 1b and braked casters 1c. Transparent tempered glass 1i is placed on both the front and rear sides of the U-shaped frame 1a. Square grooves 1d are opened on the upper part of the side walls of the U-shaped frame 1a for placing the partition 1b. The side walls of the plant experimental box 1 are provided with circular water inlets 1e and water outlets 1f at different heights. The heights of the water inlets 1e and water outlets 1f on the side walls are flush. The water supply system 2 consists of a liquid storage bottle 7, a micro-nano bubble generator 8, and a peristaltic pump 9. The liquid storage bottle 7, the micro-nano bubble generator 8, and the peristaltic pump 9 are connected in series via hoses. The water outlet of the peristaltic pump 9 is connected to the water inlet 1e of the plant experimental box via a hose. The monitoring component 3 includes a dissolved oxygen sensor, a redox potential sensor, a pH sensor, etc. The sensors in the monitoring component 3 are vertically inserted into the plant experimental box 1, and the sensors are connected to the corresponding sensor instruments through data cables. The liquid recovery bottle 4 is connected to the water outlet 1f of the plant experiment box 1 via a hose; The imaging system 6 includes a lighting box 5, a camera 11, and a computer 10 with image processing capabilities. The lighting box 5 and the camera 11 are respectively placed on the front and rear sides of the plant experiment box 1. The main body of the lighting box 5 is composed of LED lights, which are usually in the off state and are turned on when taking pictures. The liquid storage bottle 7 is composed of one individual or two connected in parallel. The liquid storage bottle 7 is used to store inorganic salt solutions, organic carbon source solutions, or surfactant solutions required for plant growth. The micro-nano bubble generator 8 produces bubbles with a particle size of 50nm-10μm and an air intake rate of 0-1L / min. The plant experiment box 1 is a box-shaped container with a transparent viewing window and an open top. The U-shaped frame 1a is made of stainless steel, with a length of 20 cm-60 cm and a height equal to its length. The inner width is 2.5 cm. Square grooves 1d are opened on both sides of the plant experiment box 1 at approximately 1 / 10 of the distance from the top, and the height of the square grooves 1d on both sides is flush. Circular holes 1h are opened on the side walls of the plant experiment box 1 at approximately 1 / 4, 1 / 2, and 3 / 4 of the distance from the top, with a diameter of 1 cm. The circular holes 1h on both sides of the plant experiment box 1 are flush. The circular holes 1h are connected inside and outside by PVC pipes, and the connection between the circular holes 1h and the PVC pipes is fixed and sealed with glue. Square transparent tempered glass 1i is placed on the front and back sides of the U-shaped frame 1a as viewing windows. The partition 1b is detachable and made of plexiglass. The partition 1b is placed in the square grooves 1d. The PVC pipe is wrapped with a 100-300 mesh stainless steel mesh on the inner end of the plant experiment box 1, and the PVC pipe is connected to the control valve 1g on the outer side of the plant experiment box 1. The sensors in the monitoring component 3 are all made of stainless steel, and the sensors in the monitoring component 3 are placed in the plant experimental box 1 near the water outlet 1f. A simulation test method for the phytoremediation process of chlorinated hydrocarbon pollutants, the method steps are as follows: Step 1: Prepare plant growth culture solution. Prepare Hoagland inorganic salt nutrient solution to simulate the plant rhizosphere growth environment and adjust the pH to 7.0. Also prepare a 10-400 mg / L carbon source solution. Step 2: Filling the simulated medium: Connect the water supply system 2, plant experiment box 1, and liquid recovery bottle 4 in sequence. Pour water into the plant experiment box 1 to test the airtightness of the device. After the test is completed, fill the plant experiment box 1 with clean quartz sand. First, fill the plant experiment box 1 with 70-80 mesh quartz sand to a height of 2-3 cm. Then, according to the experimental requirements, fill the plant experiment box 1 with quartz sand particles of appropriate particle size (10-70 mesh). The final filling height of the quartz sand should be about 3-5 cm lower than the top of the plant experiment box 1. Step 3: Install monitoring component 3: When the quartz sand is filled to about 1 / 2 of the height of the experimental box, insert the sensor vertically into the solid medium, with the sensor position close to the water outlet 1f of the plant experimental box 1. At the same time, continue to fill the plant experimental box 1 with quartz sand and other media to ensure that the sensor in monitoring component 3 is stable in the experimental device system. Step 4: Establish a simulated environment: Open the control valve 1g of the inlet 1e of the plant experiment chamber 1, and continuously inject the plant growth simulation solution into the plant experiment chamber 1 through the peristaltic pump 9 at an injection rate of 0.5 mL / min-3.0 mL / min until the plant experiment chamber 1 is full of solution. Monitor the redox potential and dissolved oxygen in the plant experiment chamber 1. After running the system for 1-2 days, the readings of the pH sensor, redox potential sensor and other components in the monitoring component 3 should be stable. Step 5: Injecting contaminants: Add an appropriate amount of indicator or tracer to the chlorinated hydrocarbon solution. The indicator or tracer is Oil Red O. Then, inject 1-7 mL of chlorinated hydrocarbon contaminants into plant experiment chamber 1 using a syringe. Let it stand for more than 24 hours to allow the distribution of chlorinated hydrocarbon contaminants in plant experiment chamber 1 to stabilize. Step 6: Plant the restoration plants. Rinse the restoration plant seeds with deionized water 5-6 times in advance, and then soak them in deionized water overnight (12h). Wrap the partition 1b with gauze (1-2 layers) and place it in the square groove 1d of the plant experiment box 1. Place the soaked plant seeds on top of the gauze. The experimental system can be placed in a dark room and the required light environment can be simulated by plant growth lamps. Step 7: After the plants have grown normally, according to the specific experimental purpose, use the above experimental system to simulate the process of plant remediation of chlorinated hydrocarbon pollutants. Maintain the room temperature at 15-30℃ and run for 20-60 days. Monitor parameters such as redox potential and dissolved oxygen in plant experimental chamber 1 every 2-5 days. Turn on the lighting box 5 in the imaging system every 5-10 days. Place the camera 11 20-50 cm in front of the center of plant experimental chamber 1 (the shooting range of camera 11 should be able to cover the viewing window area of ​​plant experimental chamber 1). The lighting box 5 has a power of 9W-45W and is placed directly behind plant experimental chamber 1, parallel to plant experimental chamber 1, 15-50 cm away from plant experimental chamber 1. The light should be perpendicular to the viewing window of plant experimental chamber 1. After the simulation experiment begins, fix the relative distance between the lighting box 5, camera 11 and plant experimental chamber 1 to ensure that the shooting angle is the same each time.

[0029] Step 8: After completing the plant growth culture, the culture solution in the plant experiment box can be replaced with a 0.01%-0.5% methylene blue solution through the water supply system. Let it stand for 3-10 minutes to stain the plant roots. Then replace the solution in the plant experiment box 1 with deionized water until it is clear, and use camera 11 to record the distribution of the plant roots.

[0030] Step 9: Import the photos taken by camera 11 into computer 10 for processing (such as Matlab software), extract the brightness of specific color channels of the image, perform pixel extraction, data analysis and other related work, analyze parameters such as in-situ dissolved oxygen and redox potential in the rhizosphere during plant growth, and analyze the distribution of plant roots and chlorinated hydrocarbon pollutants in porous media to explore the mechanism of plant remediation of organic pollutants.

[0031] Using the above data, we can analyze information such as in-situ dissolved oxygen and redox potential in the rhizosphere during plant growth, and at the same time analyze the influence of plant rhizosphere growth on the distribution of chlorinated hydrocarbon pollutants in porous media, so as to explore the process and mechanism of phytoremediation of organic pollutants.

[0032] The organic carbon source in the storage bottle 7 in step one is glucose or sodium lactate. In addition, a surfactant solution can also be added to the storage bottle 7 to solubilize pollutants and enhance phytoremediation. The chlorinated hydrocarbon pollutants in step five are chlorinated hydrocarbon compounds such as tetrachloroethylene, chlorobenzene, 1,2-dichloroethane, and 1,2-dichlorobenzene. The restoration plants in step six are carpet grass, Sudan grass, ryegrass, or alfalfa; Example 1

[0033] A simulation test system for phytoremediation of chlorinated hydrocarbon pollutants includes a water supply system 2, a plant experimental chamber 1, a monitoring component 3, a liquid recovery bottle 4, and an imaging system 6. The water supply system 2, the plant experimental chamber 1, and the liquid recovery bottle 4 are connected in sequence by silicone hoses with an inner diameter of 2-6 mm.

[0034] The plant experiment box 1 is a box-shaped container composed of a stainless steel U-shaped frame 1a and tempered glass 1i, a partition 1b, and brake casters 1c. The plant experiment box 1 has a length × width × height of 45 cm × 2.5 cm × 45 cm. Square grooves 1d are cut into the upper part of the two side walls of the plant experiment box 1. Circular holes 1h are cut into the two side walls of the plant experiment box 1 at 12.5 cm, 22.5 cm, and 32.5 cm from the top, respectively. The circular holes 1h are connected inside and outside by PVC pipes with an outer diameter of about 9 mm and a length of 10-15 mm. cm, the PVC pipe is wrapped with a 100-300 mesh stainless steel mesh on the inner end of the plant experiment box 1 to prevent the solid medium filled in the experiment box from entering the PVC pipe and clogging the pipeline. The PVC pipe on the outside of the plant experiment box 1 is equipped with a valve to control the inflow and outflow of the aqueous solution. The PVC pipe is connected to the control valve 1g on the outside of the plant experiment box 1. There is also a detachable partition 1b inside the plant experiment box 1. After the plant experiment box 1 is filled with solid medium and monitoring components, the partition 1b is wrapped with gauze (1-2 layers) and placed in the square groove 1d of the plant experiment box 1 to place the remediation plant seeds to prevent the seeds from entering the pores of the quartz sand and interfering with the distribution of pollutants. The pipeline of the water inlet 1e of the plant experiment box 1 is connected to the water supply system 2, and the pipeline at the water outlet end is connected to the liquid recovery bottle. The plant experiment box is filled with quartz sand medium particles of appropriate particle size.

[0035] The water supply system 2 consists of three parts: a liquid storage bottle 7, a nano bubble generator 8, and a peristaltic pump 9. The liquid storage bottle 7 can be a single unit or two units connected in parallel. The liquid storage bottle 7, the nano bubble generator 8, and the peristaltic pump 9 are connected in series and then connected to the water inlet 1e of the plant experimental chamber 1. The liquid storage bottle 7 can store various solutions such as nutrient elements, surfactant solutions, or staining solutions. The peristaltic pump 9 regulates the flow rate of the solution in the liquid storage bottle 7 into the plant experimental chamber 1. The micro-nano bubble generator 8 produces bubbles with a particle size of 50 nm-10 μm and an air intake of 0-1 L / min. The dissolved oxygen content in the solution is controlled at 5-30 mg / L.

[0036] The liquid recovery bottle 4 is connected to the outlet 1f of the plant experiment box 1 and is used to receive the solution flowing out of the plant experiment box 1. It can be used to collect the effluent from the plant experiment box 1, measure changes in indicators such as pollutant content, or collect the waste liquid generated during the operation of the system to prevent secondary pollution.

[0037] The monitoring component 3 consists of a set of sensors, including a dissolved oxygen sensor, a redox potential sensor, and a pH sensor. The monitoring component 3 is inserted into the solid medium of the plant experiment chamber, near the water outlet of the plant experiment chamber. The pH sensor has a detection range of 0-14 and an accuracy of ±0.05, the dissolved oxygen sensor has a detection accuracy of ±0.1 mg / L, and the redox potential sensor has a detection accuracy of ±1mV. It is used to monitor the changes in parameters such as the redox potential and dissolved oxygen in the rhizosphere environment during the plant remediation process.

[0038] The imaging system 6 includes a lighting box 5, a camera 11, and a computer 10. The camera 11 is placed directly in front of the plant experiment box 1, 20 cm to 50 cm away from the plant experiment box 1. The lighting box has a power of 9W to 45W and is placed parallel to the back of the plant experiment box 1, 15 cm to 50 cm away from the plant experiment box 1. The camera 11 has a resolution of no less than 48 million pixels and is connected to the computer 10 via a data cable.

[0039] The phytoremediation process simulation test system, with the plant experiment box 1 as the main body, can flexibly simulate the influence of plants on the distribution of pollutants in porous media under different growth environments, monitor the changes in physicochemical parameters around the root system in real time, and study the pollutant removal process of phytoremediation by tracking the changes in the distribution of pollutants in the two-dimensional system. It can also verify the effects and mechanisms of different plant growth regulation technologies (such as carbon-nitrogen ratio, inorganic nutrients, light, etc.) and solubilization enhancement technologies on the removal of organic pollutants by plants in simulated porous media. A simulation test method for the phytoremediation process of chlorinated hydrocarbon pollutants, the method steps are as follows: Step 1: Prepare plant growth culture solution. Prepare Hoagland inorganic salt nutrient solution to simulate the plant rhizosphere growth environment and adjust the pH to 7.0. Also prepare a 200 mg / L carbon source solution. Step 2: Filling the simulated medium: Connect the water supply system 2, plant experiment box 1, and liquid recovery bottle 4 in sequence. Pour water into the plant experiment box 1 to test the airtightness of the device. After the test is completed, fill the plant experiment box 1 with clean quartz sand. First, fill the 2cm high 70-mesh quartz sand, and then, according to the experimental requirements, fill the appropriate particle size (50 mesh) quartz sand particles. The final filling height of the quartz sand is about 4cm lower than the top of the plant experiment box 1. Step 3: Install monitoring component 3: When the quartz sand is filled to about 1 / 2 of the height of the experimental box, insert the sensor vertically into the solid medium, with the sensor position close to the water outlet 1f of the plant experimental box 1. At the same time, continue to fill the plant experimental box 1 with quartz sand and other media to ensure that the sensor in monitoring component 3 is stable in the experimental device system. Step 4: Establish a simulated environment: Open the control valve 1g of the inlet 1e of the plant experiment chamber 1, and continuously inject the plant growth simulation solution into the plant experiment chamber 1 through the peristaltic pump 9 at an injection rate of 1.5 mL / min until the plant experiment chamber 1 is full of solution. Monitor the redox potential and dissolved oxygen in the plant experiment chamber 1. After running the system for 2 days, the readings of the pH sensor, redox potential sensor and other components in the monitoring component 3 are stable. Step 5: Injecting contaminants: Add an appropriate amount of indicator or tracer to the chlorinated hydrocarbon solution. The indicator or tracer is Oil Red O. Then, inject 3 mL of chlorinated hydrocarbon contaminant into plant experiment chamber 1 using a syringe. Let it stand for more than 24 hours to allow the distribution of chlorinated hydrocarbon contaminant in plant experiment chamber 1 to stabilize. Step 6: Plant the restoration plants. Rinse the restoration plant seeds with deionized water 5 times in advance, and then soak them in deionized water overnight (12h). Wrap the partition 1b with gauze (2 layers) and place it in the square groove 1d of the plant experiment box 1. Place the soaked plant seeds on top of the gauze. The experimental system can be placed in a dark room and the required light environment can be simulated by plant growth lamps. Step 7: After the plants have grown normally, according to the specific experimental purpose, use the above experimental system to simulate the process of plant remediation of chlorinated hydrocarbon pollutants. Maintain the room temperature at 25℃ and run for 40 days. Monitor parameters such as redox potential and dissolved oxygen in plant experimental chamber 1 every 3 days. Turn on the lighting box 5 in the imaging system every 7 days. Place the camera 11 30cm in front of the center of plant experimental chamber 1 (the shooting range of camera 11 should be able to cover the viewing window area of ​​plant experimental chamber 1). The lighting box 5 has a power of 9W-45W and is placed directly behind plant experimental chamber 1. The lighting box 5 is parallel to plant experimental chamber 1 and 40cm away from plant experimental chamber 1. The light shines perpendicularly on the viewing window of plant experimental chamber 1. After the simulation experiment begins, fix the relative distance between the lighting box 5, camera 11 and plant experimental chamber 1 to ensure that the shooting angle is the same each time.

[0040] Step 8: After completing the plant growth culture, the culture solution in the plant experiment box can be replaced with 0.3% methylene blue solution through the water supply system. Let it stand for 8 minutes to stain the plant roots. Then replace the solution in the plant experiment box 1 with deionized water until it is clear, and use camera 11 to record the distribution of the plant roots.

[0041] Step 9: Import the photos taken by camera 11 into computer 10 for processing (such as Matlab software), extract the brightness of specific color channels of the image, perform pixel extraction, data analysis and other related work, analyze parameters such as in-situ dissolved oxygen and redox potential in the rhizosphere during plant growth, and analyze the distribution of plant roots and chlorinated hydrocarbon pollutants in porous media to explore the mechanism of plant remediation of organic pollutants.

[0042] Using the above data, we can analyze information such as in-situ dissolved oxygen and redox potential in the rhizosphere during plant growth, and at the same time analyze the influence of plant rhizosphere growth on the distribution of chlorinated hydrocarbon pollutants in porous media, so as to explore the process and mechanism of phytoremediation of organic pollutants.

[0043] The organic carbon source in the storage bottle 7 in step one is glucose or sodium lactate. In addition, a surfactant solution can also be added to the storage bottle 7 to solubilize pollutants and enhance phytoremediation. The chlorinated hydrocarbon pollutants in step five are chlorinated hydrocarbon compounds such as tetrachloroethylene, chlorobenzene, 1,2-dichloroethane, and 1,2-dichlorobenzene. The plants used for restoration in step six are carpet grass, Sudan grass, ryegrass, or alfalfa.

[0044] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A simulation experimental system for phytoremediation of chlorinated hydrocarbon pollutants, comprising a plant experimental chamber (1), a water supply system (2), a monitoring component (3), a liquid recovery bottle (4), and an imaging system (6), characterized in that: The water supply system (2), the plant experiment box (1) and the liquid recovery bottle (4) are connected in series via hoses; the imaging system (6) consists of three parts: a lighting box (5), a camera (11) and a computer (10); the lighting box (5) and the camera (11) are respectively placed on both sides of the plant experiment box (1).

2. The simulation experimental system for phytoremediation of chlorinated hydrocarbon pollutants according to claim 1, characterized in that: The plant experiment box (1) consists of a U-shaped frame (1a), transparent tempered glass (1i), partition (1b) and braked casters (1c). Transparent tempered glass (1i) is placed on both the front and rear sides of the U-shaped frame (1a). Square grooves (1d) are opened on the upper part of the side walls of the U-shaped frame (1a). The side walls of the plant experiment box (1) are provided with circular water inlets (1e) and water outlets (1f) of different heights. The water inlets (1e) and water outlets (1f) on both side walls are at the same height.

3. The simulation experimental system for phytoremediation of chlorinated hydrocarbon pollutants according to claim 1, characterized in that: The water supply system (2) consists of a liquid storage bottle (7), a micro-nano bubble generator (8) and a peristaltic pump (9). The liquid storage bottle (7), the micro-nano bubble generator (8) and the peristaltic pump (9) are connected in series by a hose. The water outlet of the peristaltic pump (9) is connected to the water inlet (1e) of the plant experimental box (1) by a hose.

4. The simulation experimental system for phytoremediation of chlorinated hydrocarbon pollutants according to claim 1, characterized in that: The monitoring component (3) includes a dissolved oxygen sensor, a redox potential sensor, and a pH sensor. The sensors in the monitoring component (3) are vertically inserted into the plant experiment box (1), and the sensors are connected to the corresponding sensor instruments via data cables.

5. The simulation test system for phytoremediation of chlorinated hydrocarbon pollutants according to claim 1, characterized in that: The liquid recovery bottle (4) is connected to the water outlet (1f) of the plant experiment box (1) via a hose.

6. The simulation test system for phytoremediation of chlorinated hydrocarbon pollutants according to claim 1, characterized in that: The plant experiment box (1) has circular holes (1h) on both sides of the wall at about 1 / 4, 1 / 2 and 3 / 4 of the distance from the top. The circular holes (1h) on both sides of the plant experiment box (1) are at the same height. The circular holes (1h) are connected inside and outside by PVC pipes. The connection between the circular holes (1h) and the PVC pipes is fixed and sealed with glue. Square transparent tempered glass (1i) is placed on the front and back sides of the U-shaped frame (1a) as viewing windows. The partition (1b) is detachable and is placed in a square groove (1d).

7. The simulation test system for phytoremediation of chlorinated hydrocarbon pollutants according to claim 6, characterized in that: The PVC pipe is wrapped with a 100-300 mesh stainless steel mesh on the inner end of the plant experiment box (1), and the PVC pipe is connected to a control valve (1g) on ​​the outer side of the plant experiment box (1).

8. The simulation test method for phytoremediation of chlorinated hydrocarbon pollutants according to claim 1, characterized in that: The method and steps are as follows: Step 1: Prepare plant growth culture solution. Prepare Hoagland inorganic salt nutrient solution to simulate the plant rhizosphere growth environment and adjust the pH to 7.

0. Also prepare a 10-400 mg / L carbon source solution. Step 2: Filling the simulated medium: Connect the water supply system (2), plant experiment box (1), and liquid recovery bottle (4) in sequence. Pour water into the plant experiment box (1) to test the airtightness of the device. After the test is completed, fill the plant experiment box (1) with clean quartz sand. First, fill the plant experiment box (1) with 70-80 mesh quartz sand with a height of 2-3cm. Then, according to the experimental requirements, fill the plant experiment box (1) with quartz sand particles of appropriate size. The final filling height of the quartz sand is about 3-5cm lower than the top of the plant experiment box (1). Step 3: Install the monitoring component (3): When the quartz sand is filled to about 1 / 2 of the height of the experimental box, insert the sensor vertically into the solid medium. The sensor position is close to the water outlet (1f) of the plant experimental box (1). At the same time, continue to fill the plant experimental box (1) with quartz sand medium to ensure that the sensor in the monitoring component (3) is stable in the experimental device system. Step 4: Establish a simulated environment: Open the control valve (1g) of the inlet (1e) of the plant experiment box (1), and continuously inject the plant growth simulation solution into the plant experiment box (1) at an injection rate of 0.5 mL / min-3.0 mL / min using the peristaltic pump (9) until the plant experiment box (1) is full of solution. Monitor the redox potential and dissolved oxygen in the plant experiment box (1). After running the system for 1-2 days, the pH sensor and redox potential sensor readings in the monitoring component (3) are expected to stabilize. Step 5: Injecting contaminants: Add an appropriate amount of indicator or tracer to the chlorinated hydrocarbon solution. The indicator or tracer is Oil Red O. Then, inject 1-7 mL of chlorinated hydrocarbon contaminants into the plant experiment box (1) using a syringe. Let it stand for more than 24 hours until the distribution of chlorinated hydrocarbon contaminants in the plant experiment box (1) is stable. Step 6: Plant the restoration plants. Rinse the restoration plant seeds with deionized water 5-6 times in advance, and then soak them in deionized water overnight. Wrap the partition (1b) with gauze and place it in the square trough (1d) of the plant experiment box (1). Place the soaked plant seeds on top of the gauze. The experimental system can be placed in a dark room and the required light environment can be simulated by plant growth lamps. Step 7: After the plants grow normally, according to the specific experimental purpose, use the above experimental system to simulate the process of plant remediation of chlorinated hydrocarbon pollutants. The room temperature is maintained at 15-30℃, the running time is 20-60 days, the redox potential and dissolved oxygen parameters in the plant experimental box (1) are monitored every 2-5 days, and the lighting box (5) in the imaging system is turned on every 5-10 days. The camera (11) is placed 20-50cm in front of the center of the plant experimental box (1). The power of the lighting box (5) is 9W-45W, and it is placed behind the plant experimental box (1). The lighting box (5) is parallel to the plant experimental box (1) and 15-50cm away from the plant experimental box (1). The light shines vertically on the viewing window of the plant experimental box (1). After the simulation experiment starts, fix the relative distance between the lighting box (5), the camera (11) and the plant experimental box (1) to ensure that the shooting angle is the same each time. Step 8: After the plant growth culture is completed, the culture solution in the plant experiment box (1) can be replaced with 0.01%-0.5% methylene blue solution through the water supply system. Let it stand for 3-10 minutes to stain the plant roots. Then replace the solution in the plant experiment box (1) with deionized water until it is clear. Use a camera (11) to record the distribution of the plant roots. Step 9: Import the photos taken by the camera (11) into the computer (10) for processing, extract the brightness of specific color channels of the image, perform pixel extraction and data analysis, analyze the in-situ dissolved oxygen and redox potential parameters of the rhizosphere during plant growth, and analyze the distribution of plant roots and chlorinated hydrocarbon pollutants in porous media to explore the mechanism of plant remediation of organic pollutants.

9. The simulation test method for phytoremediation of chlorinated hydrocarbon pollutants according to claim 8, characterized in that: The chlorinated hydrocarbon pollutants in step five are tetrachloroethylene, chlorobenzene, 1,2-dichloroethane, and 1,2-dichlorobenzene chlorinated hydrocarbon compounds.

10. The simulation test method for phytoremediation of chlorinated hydrocarbon pollutants according to claim 8, characterized in that: The plants used for restoration in step six are carpet grass, Sudan grass, ryegrass, or alfalfa.

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