In-situ remediation method and system for heavy metal contaminated soil

Abstract

The invention discloses an in-situ remediation method and system for heavy metal contaminated soil. The method comprises the steps that a remediation area is established in situ along the heavy metal contaminated soil, an external electric field is applied to the two ends of the remediation area, enrichment plants are evenly planted in the remediation area, the external electric field is communicated with a direct-current power source, and the voltage gradient of the remediation area is controlled to be 0.3 V / cm to 0.5 V / cm. The heavy metal contaminated soil is remedied through the enrichment plants, meanwhile, the anode electrolysis chamber and the cathode electrolysis chamber are used for applying an external electric field to the remediation area, the remediation efficiency is greatly improved through cooperation with the enrichment plants, and the purpose of cleaning the contaminated soil is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil remediation, and in particular relates to a method and system for in-situ remediation of heavy metal contaminated soil. Background Art

[0002] Most soils are contaminated by heavy metals, especially soils around key polluting enterprises and soils around centralized solid waste treatment and disposal sites. Exploring low-carbon and high-efficiency technologies to repair soils contaminated by heavy metals is of great significance to environmental safety and food security.

[0003] At present, for several commonly used remediation methods, the chemical leaching method for soil remediation will not only seriously affect the soil structure, but its leaching agent may also cause secondary pollution. The remediation process of microbial remediation is difficult to control and is greatly affected by temperature and humidity, and heavy metals may be released again. The long-term stability of chemical reduction is not good enough, which affects the soil structure and pH.

[0004] In comparison, phytoremediation is a low-cost, eco-friendly in-situ remediation technology that uses plants to extract, transfer and transform heavy metals to achieve the purpose of cleaning contaminated soil. However, due to factors such as slow plant growth, low biomass, low heavy metal transfer coefficient, and low bioavailability of heavy metals in soil, the efficiency of soil heavy metal pollution remediation is affected. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a method and system for in-situ remediation of heavy metal contaminated soil. The method combines electrodynamics with phytoremediation and applies an external electric field to the soil in the remediation area, which can effectively increase the soluble heavy metal content in the soil and drive the heavy metals to migrate to the roots of plants through the action of electrodynamics, thereby promoting the absorption of heavy metals by plants and improving the efficiency of phytoremediation.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A method for in-situ remediation of heavy metal contaminated soil, comprising:

[0008] Establishing in situ remediation areas along heavy metal contaminated soils;

[0009] Apply an external electric field at both ends of the restoration area and evenly plant enrichment plants in the restoration area;

[0010] The external electric field is connected to a DC power supply to control the voltage gradient of the repair area to be 0.3-0.5 V / cm.

[0011] In one embodiment, it further comprises:

[0012] A solar photovoltaic panel is provided, and a controller is used to connect the solar photovoltaic panel with a storage battery, and the storage battery with a DC power supply;

[0013] Through this implementation, solar photovoltaic panels and batteries are set up to continuously apply an external electric field to the repair area, and low energy consumption is achieved, achieving an ecological and low-carbon effect.

[0014] In one embodiment, applying an external electric field at both ends of the repair area includes:

[0015] An anode electrolysis chamber is provided at one end of the repair area, and a cathode electrolysis chamber is provided at the other end;

[0016] Filter plates are provided on the side of the anode electrolysis chamber and the cathode electrolysis chamber close to the repair area;

[0017] The two ends of the DC power supply are respectively connected to the graphite felt electrodes arranged in the anode electrolysis chamber and the cathode electrolysis chamber to form an external electric field to acidify the heavy metal contaminated soil;

[0018] Through this implementation, an external electric field is applied to the restoration area using the anode electrolysis chamber and the cathode electrolysis chamber. On the one hand, hydrolysis and acidification occur in the anode area, which promotes the desorption and activation of soil heavy metals, significantly increasing the content of dissolved heavy metals in the soil. Under the action of electrodynamic forces such as electrodialysis, electromigration, and electrophoresis, heavy metals can effectively migrate to the root system, facilitating the capture and absorption of the root system. On the other hand, a suitable electric field can change the activity of plant enzymes, membrane permeability, and the state of intracellular water molecules, enhance plant resistance, promote plant photosynthesis, and thereby increase plant biomass and the absorption and transport of heavy metals, greatly improving the efficiency of plant restoration.

[0019] The present invention also provides an in-situ remediation system for heavy metal contaminated soil, which applies the above-mentioned in-situ remediation method for heavy metal contaminated soil, including establishing a remediation area in situ in the metal contaminated soil, uniformly planting enrichment plants in the remediation area, and providing an external electric field connected to a DC power supply at both ends of the remediation area, wherein the external electric field applies a voltage gradient of 0.3 to 0.5 V / cm to the remediation area.

[0020] In one embodiment, it further comprises a solar photovoltaic panel, wherein the solar photovoltaic panel is connected to a battery through a controller, and the battery is connected to the DC power supply.

[0021] In one embodiment, the external electric field includes an anode electrolysis chamber and a cathode electrolysis chamber arranged at both ends of the repair area, and the cathode electrolysis chamber and the anode electrolysis chamber are both provided with graphite felt electrodes connected to a DC power supply, and the anode electrolysis chamber and the cathode electrolysis chamber are both provided with filter plates on one side close to the repair area.

[0022] In one embodiment, the anode electrolysis chamber and the cathode electrolysis chamber are both connected to a storage tank.

[0023] In one embodiment, the filter plate comprises a perforated isolation plate extending in a vertical direction, and the perforated isolation plate is wrapped with filter paper.

[0024] In one embodiment, electrolyte outlets are provided on the side walls of the anode electrolysis chamber and the cathode electrolysis chamber, and the electrolyte outlets are connected to the reserve tank through a reserve pipeline. A peristaltic pump is provided on the reserve pipeline, and the peristaltic pump is connected to the battery.

[0025] The beneficial effects of the present invention are:

[0026] (1) Using enrichment plants to repair heavy metal contaminated soil, and using the anode electrolysis chamber and cathode electrolysis chamber to apply an external electric field to the repair area, cooperating with the enrichment plants, greatly improving the repair efficiency. On the one hand, hydrolysis and acidification occur in the anode area, which promotes the desorption and activation of soil heavy metals, significantly increasing the content of dissolved heavy metals in the soil, and under the action of electrodynamic forces such as electrodialysis, electromigration, and electrophoresis, heavy metals can effectively migrate to the root system, facilitating the capture and absorption of the root system. On the other hand, a suitable electric field can change the plant enzyme activity, membrane permeability, and the state of intracellular water molecules, enhance plant resistance, and promote plant photosynthesis, thereby increasing plant biomass and the absorption and transport of heavy metals, greatly improving the efficiency of plants in repairing heavy metal contaminated soil;

[0027] (2) Install solar photovoltaic panels and batteries to supply DC power, continuously apply an external electric field to the restoration area, and consume less energy to achieve an ecological and low-carbon effect;

[0028] (3) The storage tank connected to the anode electrolysis chamber and the cathode electrolysis chamber can prevent the electrolyte level in the electrolysis chamber from being too high or too low, thereby ensuring the soil repair effect; BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0030] Figure 1 A schematic structural diagram of an embodiment of the present invention is shown;

[0031] In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0032] Reference numerals:

[0033] 1-graphite felt electrode, 2-electrode fixing clip, 3-electrode fixing plate, 4-filter paper, 5-perforated isolation plate, 6-repair area, 7-enriched plants, 8-anode electrolysis chamber, 9-cathode electrolysis chamber, 10-electrolyte outlet, 11-peristaltic pump, 12-anode electrolyte storage tank, 13-cathode electrolyte storage tank, 14-DC power supply, 15-battery, 16-controller, 17-solar photovoltaic panel. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings.

[0035] Most of the current methods for remediating heavy metal contaminated soil have some shortcomings, such as affecting soil structure, causing secondary pollution, difficult to control the remediation process, poor stability or low remediation efficiency.

[0036] The present invention provides a method for in-situ remediation of heavy metal contaminated soil, comprising:

[0037] Establishing in situ remediation areas along heavy metal contaminated soils;

[0038] Apply an external electric field at both ends of the restoration area and evenly plant enrichment plants in the restoration area;

[0039] The external electric field is connected to a DC power supply to control the voltage gradient of the repair area to be 0.3-0.5 V / cm;

[0040] It should be noted that the use of enriched plants for phytoremediation of heavy metal soil is relatively low in cost. Plants are used to extract, transfer and transform heavy metals to achieve the purpose of cleaning contaminated soil. At the same time, electrokinetic force is combined with phytoremediation to apply an external electric field to the soil in the remediation area, which can effectively increase the soluble heavy metal content in the soil, and drive the heavy metals to migrate to the roots of plants through electrokinetic force, promote the absorption of heavy metals by plants, and greatly improve the efficiency of phytoremediation.

[0041] Specifically, an external electric field is applied at both ends of the repair area, including:

[0042] An anode electrolysis chamber is provided at one end of the repair area, and a cathode electrolysis chamber is provided at the other end;

[0043] Filter plates are provided on the side of the anode electrolysis chamber and the cathode electrolysis chamber close to the repair area;

[0044] The two ends of the DC power supply are respectively connected to the graphite felt electrodes arranged in the anode electrolysis chamber and the cathode electrolysis chamber to form an external electric field to acidify the heavy metal contaminated soil;

[0045] It should be noted that the use of the set anode electrolysis chamber and cathode electrolysis chamber can not only enclose the restoration area, but also plant enrichment plants in the restoration area, and at the same time apply an external electric field to the restoration area. On the one hand, hydrolysis and acidification occur in the anode area, which promotes the desorption and activation of soil heavy metals, significantly increases the content of dissolved heavy metals in the soil, and under the action of electrodynamic forces such as electrodialysis, electromigration, and electrophoresis, heavy metals can effectively migrate to the root system, facilitating the capture and absorption of the root system. On the other hand, a suitable electric field can change the plant enzyme activity, membrane permeability, and the state of intracellular water molecules, enhance plant resistance, promote plant photosynthesis, and thereby increase plant biomass and the absorption and transport of heavy metals, greatly improving the efficiency of plant restoration;

[0046] In one embodiment, it further includes:

[0047] Install solar photovoltaic panels, use a controller to connect the solar photovoltaic panels with batteries, and connect the batteries with DC power supplies, that is, by installing solar photovoltaic panels and batteries, continuously apply an external electric field to the restoration area, consume less energy, and achieve an ecological low-carbon effect;

[0048] The present invention also provides an in-situ remediation system for heavy metal contaminated soil. Figure 1 As shown, it includes a remediation area 6 established in situ in the metal contaminated soil, and enrichment plants 7 are evenly planted in the remediation area 6. An external electric field connected to a DC power supply 14 is also provided at both ends of the remediation area 6, and the external electric field applies a voltage gradient of 0.3 to 0.5 V / cm to the remediation area 6;

[0049] Specifically, Figure 1 As shown, the external electric field includes an anode electrolysis chamber 8 and a cathode electrolysis chamber 9 arranged at both ends of the repair area 6, and a graphite felt electrode 1 connected to a DC power supply 14 is arranged in the cathode electrolysis chamber 9 and the anode electrolysis chamber 8, and a filter plate is arranged on one side of the anode electrolysis chamber 8 and the cathode electrolysis chamber 9 close to the repair area 6;

[0050] It should be noted that if Figure 1 As shown, the anode electrolysis chamber 8 and the cathode electrolysis chamber 9 enclose a restoration area 6, and enrichment plants 7 are planted in the restoration area 6. The anode electrolysis chamber 8 and the cathode electrolysis chamber 9 are both connected to a DC power supply 14. When power is supplied, an external electric field is applied to the restoration area 6. On the one hand, hydrolysis and acidification occur in the anode area, which promotes the desorption and activation of soil heavy metals, significantly increases the content of dissolved heavy metals in the soil, and under the action of electrodynamic forces such as electrodialysis, electromigration, and electrophoresis, heavy metals can effectively migrate to the root system, which is convenient for the capture and absorption of the root system. On the other hand, a suitable electric field can change the plant enzyme activity, membrane permeability, and the state of intracellular water molecules, enhance plant resistance, promote plant photosynthesis, and thereby increase plant biomass and the absorption and transport of heavy metals, greatly improving the efficiency of plant restoration;

[0051] Specifically, an electrode fixing clamp 2 and an electrode fixing plate 3 are provided in both the anode electrolysis chamber 8 and the cathode electrolysis chamber 9 to fix the graphite felt electrode 1;

[0052] In one embodiment, Figure 1 As shown, it also includes a solar photovoltaic panel 17, which is connected to the battery 15 through the controller 16, and the battery 15 is connected to the DC power supply 14, that is, by setting the solar photovoltaic panel 17 and the battery 15, an external electric field is continuously applied to the repair area 6, which consumes less energy and achieves an ecological low-carbon effect;

[0053] Specifically, the filter plate includes a perforated isolation plate 5 extending in the vertical direction, and the perforated isolation plate 5 is wrapped with a filter paper 4, that is, to prevent the electrolyte in the anode electrolysis chamber 8 and the cathode electrolysis chamber 9 from leaking out, while ensuring that the heavy metal cations migrate to the cathode electrolysis chamber 9 and the heavy metal anions migrate to the anode electrolysis chamber 8;

[0054] In one embodiment, the anode electrolysis chamber 8 and the cathode electrolysis chamber 9 are both connected to a storage tank, and an electrolyte outlet 10 is provided on the side wall of the anode electrolysis chamber 8 and the cathode electrolysis chamber 9, and the electrolyte outlet 10 is connected to the storage tank through a storage pipeline, and a peristaltic pump 11 is provided on the storage pipeline, and the peristaltic pump 11 is connected to the battery 15;

[0055] Specifically, Figure 1 As shown, an electrolyte outlet 10 is provided on the side wall of the anode electrolysis chamber 8, which is connected to the anode electrolyte storage tank 12 through a storage pipeline, and an electrolyte outlet 10 is provided on the side wall of the cathode electrolysis chamber 9, which is connected to the cathode electrolyte storage tank 13 through a storage pipeline. A peristaltic pump 11 connected to a battery 15 is provided on the storage pipeline to prevent the electrolyte level in the anode electrolysis chamber 8 or the cathode electrolysis chamber 9 from being too high or too low;

[0056] In one embodiment, the solar photovoltaic panel 17 converts solar energy into electrical energy, and continuously charges the battery 15 via the controller 16. According to the main type of heavy metals to be repaired, the corresponding enrichment plants 7 are selected and evenly planted in the repair area 6. The battery 15 is connected to the DC power supply 14, and the DC power supply 14 controls the voltage gradient of the repair area 6 to be 0.3-0.5V / cm, so as to achieve sustainable repair. After the power is turned on, the soil is acidified, and the heavy metals in the soil are desorbed and activated. Under the action of the electric field force, the heavy metal cations migrate to the cathode electrolysis chamber 9, and the heavy metal anions migrate to the anode electrolysis chamber 8. Under the stimulation of weak current, the biomass growth of the enrichment plants 7 is accelerated, and the absorption and transport of heavy metals are enhanced, so as to achieve the effect of sustainable, low-carbon and efficient repair of heavy metal-contaminated soil;

[0057] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0058] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A method for in-situ remediation of heavy metal contaminated soil, It is characterized in that include: Establishing in situ remediation areas along heavy metal contaminated soils; Apply an external electric field at both ends of the restoration area and evenly plant enrichment plants in the restoration area; The external electric field is connected to a DC power supply to control the voltage gradient of the repair area to be 0.3-0.5 V / cm.

2. A method for in-situ remediation of heavy metal contaminated soil according to claim 1, It is characterized in that Also includes: A solar photovoltaic panel is arranged, and a controller is used to connect the solar photovoltaic panel with a storage battery, and the storage battery with a DC power supply.

3. The in-situ remediation method for heavy metal contaminated soil according to claim 1, It is characterized in that Apply an external electric field at both ends of the repair area, including: An anode electrolysis chamber is provided at one end of the repair area, and a cathode electrolysis chamber is provided at the other end; Filter plates are provided on the side of the anode electrolysis chamber and the cathode electrolysis chamber close to the repair area; The two ends of the direct current power supply are respectively connected to the graphite felt electrodes arranged in the anode electrolysis chamber and the cathode electrolysis chamber to form an external electric field to acidify the heavy metal contaminated soil.

4. A system for in-situ remediation of heavy metal contaminated soil, using the in-situ remediation method for heavy metal contaminated soil according to any one of claims 1 to 3, It is characterized in that The invention comprises a restoration area established in situ on metal-contaminated soil, wherein enrichment plants are evenly planted in the restoration area, and an external electric field connected to a direct current power source is arranged at both ends of the restoration area, wherein the external electric field applies a voltage gradient of 0.3 to 0.5 V / cm to the restoration area.

5. A heavy metal contaminated soil in-situ remediation system according to claim 4, It is characterized in that It also includes a solar photovoltaic panel, which is connected to a battery through a controller, and the battery is connected to the DC power supply.

6. A heavy metal contaminated soil in-situ remediation system according to claim 5, It is characterized in that The external electric field includes an anode electrolysis chamber and a cathode electrolysis chamber arranged at both ends of the repair area, and the cathode electrolysis chamber and the anode electrolysis chamber are both provided with graphite felt electrodes connected to a DC power supply, and the anode electrolysis chamber and the cathode electrolysis chamber are both provided with filter plates on one side close to the repair area.

7. A heavy metal contaminated soil in-situ remediation system according to claim 6, It is characterized in that The anode electrolysis chamber and the cathode electrolysis chamber are both connected to a storage tank.

8. The in-situ remediation system for heavy metal contaminated soil according to claim 6, It is characterized in that The filter plate comprises a perforated isolation plate extending in a vertical direction, and the perforated isolation plate is wrapped with filter paper.

9. The in-situ remediation system for heavy metal contaminated soil according to claim 7, It is characterized in that The side walls of the anode electrolysis chamber and the cathode electrolysis chamber are both provided with electrolyte outlets, and the electrolyte outlets are both connected to the reserve tank through a reserve pipeline. A peristaltic pump is arranged on the reserve pipeline, and the peristaltic pump is connected to the battery.

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