CN112474773B - Device and method for strengthening soil remediation by combining plant microorganism electrochemistry and application - Google Patents
Device and method for strengthening soil remediation by combining plant microorganism electrochemistry and application Download PDFInfo
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- CN112474773B CN112474773B CN202011229336.7A CN202011229336A CN112474773B CN 112474773 B CN112474773 B CN 112474773B CN 202011229336 A CN202011229336 A CN 202011229336A CN 112474773 B CN112474773 B CN 112474773B
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Abstract
The invention relates to the technical field of soil remediation, in particular to a device and a method for strengthening soil remediation by combining plant microorganism electrochemistry and application. The repairing device specifically comprises a graphite/carbon tubular anode (1), a titanium wire lead (2) connected with the graphite/carbon tubular anode, a stainless steel mesh counter electrode (3), a titanium sheet lead (4) connected with the stainless steel mesh counter electrode, a constant potential rectifier (5) with a real-time current collecting function, a repairing plant (6), an outer lead (7) connected with the anode titanium wire lead (2) and the counter electrode titanium sheet lead (4), and a wireless current signal collecting and data processing system (8). The three degradation modes are combined, so that a novel soil remediation technology which is environment-friendly, low in cost and remarkable in effect is formed. In addition, the invention also discloses a repairing method and application thereof. The method can be conveniently applied to in-situ repair of an actual site and can utilize a radio flow data acquisition system to remotely monitor the repair condition in real time.
Description
Technical Field
The invention relates to the technical field of soil remediation, in particular to a device and a method for strengthening soil remediation by combining plant microorganism electrochemistry and application.
Background
With the development of agriculture and industry in China, a large number of organic chemical input products including toxic and harmful substances such as pesticides, antibiotics, hormones, phthalate esters, petroleum hydrocarbons and the like enter soil. This causes destruction of ecological environment and seriously affects human health, so the remediation of organically contaminated soil is difficult and urgent. The current remediation methods for organic contaminated soil can be divided into physical remediation, chemical remediation and biological remediation according to different application principles, wherein the biological remediation comprises microbial remediation and phytoremediation.
The physical remediation technology of organic soil pollutants mainly comprises a soil replacement method, a thermal desorption method, a gas phase extraction method, a charcoal adsorption method, an electric remediation method and the like. The soil replacement method is to replace or partially replace polluted soil with clean soil so as to achieve the purposes of diluting the concentration of pollutants, improving the environmental capacity of the soil and treating the polluted soil. The soil replacement method does not remove pollutants from the soil, often causes secondary pollution, and is not suitable for large-area pollution remediation. Thermal desorption techniques employ microwave, steam, infrared radiation, and the like to heat the soil contaminated by volatile organic compounds to volatilize the contaminants for removal from the soil. This technique is often relatively expensive and is prone to the release of toxic and harmful gases. The gas phase extraction method utilizes the negative pressure generated by the extraction well to volatilize the organic matters absorbed in the soil into the gas phase and extract the organic matters, is an in-situ repair technology with strong operability, but has higher matched equipment cost. The soil electrokinetic remediation technology is a novel technology for directionally moving pollutants by utilizing electrochemistry and electrodynamics, has wide remediation range and low influence on the environment, but often needs to add chemical reagents to increase the solubility and mobility of soil petroleum hydrocarbon for remediation, and can also cause secondary pollution.
Chemical remediation refers to the addition of chemicals or solvents to contaminated soil to stabilize, dissolve, or convert the contaminants into a form that is harmless or less toxic to the soil, plants, and humans. Common chemical remediation technologies for organic contaminated soil include chemical leaching, chemical oxidation, plasma degradation, photocatalytic degradation, and the like. Chemical leaching is to wash contaminated soil with a cosolvent or surfactant to dissolve harmful substances in the soil into the leacheate to separate the leacheate from the soil. The common surfactant and cosolvent often have certain toxicity, and can take away part of nutrients in soil in the leaching process, so that the soil fertility is reduced. The purpose of chemical oxidation is to oxidize organic pollutants in the soil to less dangerous or harmless substances, e.g. complete oxidation to produce CO2And H2And O. The chemical oxidants commonly used at present are ozone, hydrogen peroxide, potassium permanganate, persulfate, Fenton reagent and the like. Plasma degradation is a novel environmental pollution remediation technology, and the degradation of organic pollutants is promoted by using plasmas generated by gas molecule ionization and a large number of free radicals with strong oxidizing property. The photocatalytic degradation is realized by utilizing the absorption of light energy of semiconductor materials under the illumination conditionAn electron transition is performed to generate holes on the valence band of the semiconductor with the ability to trap electrons, to generate free radicals in the presence of water and to effect oxidation of organic contaminants.
Although the aforementioned physical and chemical remediation technologies can remove organic pollutants from soil relatively quickly, these methods tend to destroy the structure and micro-ecological environment of the soil, and also inevitably produce secondary pollution, and are not suitable for large-area pollution treatment. The biological repair comprises phytoremediation and microbial repair, which respectively remove organic pollutants in soil by using the growth metabolism of plants and microbes, has low risk to the environment and simple operation, and is a green and effective repair measure. Phytoremediation is the use of green plants to immobilize or adsorb contaminants and to purify them or reduce or even eliminate their environmental risks. The key of phytoremediation lies in the screening of plant species, and plants capable of degrading petroleum hydrocarbons in soil need not only high hydrocarbon pollution tolerance, but also a developed root system and vigorous growth capacity. Microbial remediation takes advantage of the metabolic diversity of microorganisms, degrading organic pollutants to provide energy and carbon sources. Compared with phytoremediation, the method has lower remediation cost and shorter operation period. The currently emerging soil microorganism electrochemical remediation technology is to use a manually added solid electrode as a continuous electron acceptor, receive extracellular electrons generated by metabolism of electrogenic microorganisms near an anode and transmit the extracellular electrons to an air counter electrode through an external circuit, react with oxygen and hydrogen ions in soil to generate water molecules (taking the air counter electrode as an example), and form a closed loop. This process can be carried out either spontaneously (microbial fuel cells) or under the action of an external potential (microbial electrolysis cells). The soil microorganism electrochemical restoration technology overcomes the problem of electron acceptor shortage in the traditional soil restoration process, and the current in the loop can stimulate the activity of functional bacteria, so the soil microorganism electrochemical restoration technology is a green and safe biological stimulation restoration technology.
Disclosure of Invention
The invention considers that the pollutant components in the soil are very complex and relate to the physical, chemical and biological processes of adsorption, migration, conversion, degradation and the like of pollutants, and the better repairing effect is difficult to realize by only depending on one technology. The invention provides a device for restoring the polluted soil by combining plants, microorganisms and electrochemistry from the aspects of environmental sustainability and green restoration, is applied to restoring the soil polluted by petroleum hydrocarbon, and realizes a better restoration effect. The invention aims to perfect the current soil remediation technology system and realize a novel soil remediation technology which is environment-friendly, low in cost, remarkable in effect and suitable for in-situ. The principle of the invention for strengthening the soil remediation effect is to combine the adsorption and absorption of soil pollutants by plants, the degradation of soil pollutants by rhizosphere microorganisms, and the strengthening degradation of soil pollutants by the electrochemical domestication of electrogenesis microorganisms through the electronic output of an external electrode. The repairing device and the repairing method are suitable for soil in-situ repairing, microbial agents and chemical substances do not need to be added, the landscape ecological function is provided while pollutants are removed, the repairing condition can be remotely monitored in real time by utilizing a radio flow data collecting system, and the repairing device and the repairing method are a soil combined repairing technology with a prospect.
In order to achieve the above object, the present invention provides the following technical solutions: a device for strengthening soil remediation by combining plant microorganism electrochemistry comprises a graphite/carbon tubular anode 1, a titanium wire lead 2 connected with the graphite/carbon tubular anode, a stainless steel mesh counter electrode 3, a titanium sheet lead 4 connected with the stainless steel mesh counter electrode, a constant potential rectifier 5 with a real-time current acquisition function, a remediation plant 6, an outer lead 7 connecting the anode titanium wire lead 2 and the counter electrode titanium sheet lead 4, and a wireless current signal acquisition and data processing system 8.
Preferably, the graphite/carbon tubular anode 1 has an inner diameter of 5 to 30cm, a thickness of 0.5 to 5cm, and a height of 2 to 30 cm. Preferably, the diameter of the stainless steel mesh counter electrode 3 mesh is 0.05-0.8 mm, the aperture is 0.05-1 mm, the length is 5-500 cm, and the height is 2-50 cm.
Preferably, the potentiostat 5 with the real-time current acquisition function is connected with the anode titanium wire lead 2 and the counter electrode titanium sheet lead 4 through the outer lead 7 to provide the device with a constant potential of 0.1-10V, has 1-30 channels to acquire the current (0.01-5 mA) of each channel in real time, and has a wireless signal transmission function.
Preferably, the restoration plants 6 have high soil pollutant tolerance or accumulation and can adapt to the high water content conditions in the soil electrochemical system, such as iris, reed, rice, calamus, and lotus.
The invention also provides a combined plant microorganism electrochemistry reinforced soil remediation method, which comprises the following steps:
inserting the graphite/carbon tubular anode 1, the titanium wire lead 2 connected with the graphite/carbon tubular anode, the stainless steel mesh counter electrode 3 and the titanium sheet lead 4 connected with the stainless steel mesh counter electrode into soil to be repaired;
planting the repairing plant 6 in the middle of the graphite/carbon tubular anode 1;
sufficient water is added to ensure that the soil is wet to reduce the resistivity of the device;
the potentiostat 5 is connected with the anode titanium wire lead 2 and the counter electrode titanium sheet lead 4 through the outer lead 7 to provide constant potential for the device for repairing;
the current change is monitored in real time by the wireless current signal acquisition and data processing system 8 to reflect the degradation condition of pollutants.
Preferably, the depth of the graphite/carbon tubular anode 1 and the stainless steel mesh counter electrode 3 inserted into the soil is 2-50 cm, and the planting depth of the restoration plant 6 is 2-30 cm.
The invention also provides application of the plant microorganism-combined electrochemical reinforced soil remediation method in soil remediation.
The principle of the invention for strengthening the soil remediation effect comprises the following steps: 1. the method comprises the following steps of (1) adsorption and absorption of soil pollutants by plants, degradation of soil pollutants by rhizosphere microorganisms, and electronic output of electrochemically domesticated electrogenesis microorganisms by using an external electrode so as to generate enhanced degradation of soil pollutants.
The invention has the advantages and beneficial effects that:
the device for strengthening the soil remediation by combining the plant microorganism electrochemistry provided by the invention combines the adsorption and absorption effects of plants on soil pollutants, the degradation effect of rhizosphere microorganisms on the soil pollutants, and the degradation effect of electrochemically domesticated electrogenesis microorganisms on the pollutants generated by the electronic output of an external electrode. The repairing device and the repairing method are suitable for soil in-situ repairing, microbial agents and chemical substances do not need to be added, the landscape ecological function is provided while pollutants are removed, the repairing condition can be monitored in real time by utilizing a radio flow data collecting system, and the repairing device and the repairing method are a soil combined repairing technology with a prospect.
Drawings
FIG. 1 is a diagram of an apparatus for electrochemically enhancing soil remediation by combining plant microorganisms according to an embodiment of the present invention;
FIG. 2 is a diagram showing the current change in the combined plant-microorganism-electrochemical enhanced soil remediation process of the present invention, wherein the darker color is the current of TG group, TG1-3 represents the current at different positions from the counter electrode, respectively, the lighter color is the current of CF group, and CF1-3 represents the current at different positions from the counter electrode, respectively;
FIG. 3 is a distribution of sampling positions for each set of reactors of the present invention, in which S1-3 represents the position of the anode at a distance of 6cm from the counter electrode, S4-6 represents the position of the anode at a distance of 24cm from the counter electrode, and S7-9 represents the position of the anode at a distance of 42cm from the counter electrode;
FIG. 4 shows the change of Total Organic Carbon (TOC) in soil of each group after 15 days of remediation in example 1 and comparative examples 2-4 of the present invention;
FIG. 5 shows the removal of Total Petroleum Hydrocarbons (TPH) from soil groups after 30 days of remediation in example 1 and comparative examples 2 to 4.
Reference numerals: wherein, the device comprises 1-graphite/carbon tube, 2-titanium wire, 3-stainless steel net, 4-titanium sheet, 5-potentiostat, 6-repair plant, 7-external wire, and 8-wireless signal collection and data processing system.
Detailed Description
The invention provides a device for strengthening soil remediation by combining plant microorganism electrochemistry, which comprises a graphite/carbon tubular anode 1, a titanium wire 2 connected with the graphite/carbon tubular anode, a stainless steel mesh counter electrode 3, a titanium sheet wire 4 connected with the stainless steel mesh counter electrode, a potentiostat 5 with a real-time current acquisition function, a remediation plant 6, an external wire 7 connecting the anode titanium wire 2 and the counter electrode titanium sheet wire 4, and a wireless current signal acquisition and data processing system 8.
In the invention, the inner diameter of the graphite/carbon tubular anode 1 is preferably 5-30 cm, and more preferably 10 cm; the thickness is preferably 0.5-5 cm, and more preferably 1 cm; the height is preferably 2-30 cm, and more preferably 10 cm.
In the invention, the diameter of the stainless steel net counter electrode 3 is preferably 0.05-0.8 mm, and more preferably 0.5 mm; the aperture is preferably 0.05-1 mm, and more preferably 0.42 mm; the length is preferably 5-500 cm, and more preferably 48 cm; the height is preferably 2-50 cm, and more preferably 10 cm.
In the invention, the potentiostat 5 with the real-time current acquisition function is connected with the anode titanium wire lead 2 and the counter electrode titanium sheet lead 4 through the external lead 7 to provide the device with a constant potential of preferably 0.1-10V, more preferably 0.7V, and has 1-30 passages, preferably 10 passages; the current (0.01-5 mA) of each channel is collected in real time, and the signal transmission function is achieved.
In the present invention, the remediation plants 6 have high soil contaminant tolerance or accumulation and are capable of accommodating the high moisture content conditions in soil electrochemical systems, preferably Iris tectorum (Iris tectorum).
The invention provides a method for strengthening soil remediation by combining plant-microorganism-electrochemistry, which comprises the following steps:
inserting the graphite/carbon tubular anode 1, the titanium wire lead 2 connected with the graphite/carbon tubular anode, the stainless steel mesh counter electrode 3 and the titanium sheet lead 4 connected with the stainless steel mesh counter electrode into soil to be repaired;
planting the repairing plant 6 in the middle of the graphite/carbon tubular anode 1;
sufficient water is added to ensure that the soil is wet to reduce the resistivity of the device;
the potentiostat 5 is connected with the anode titanium wire lead 2 and the counter electrode titanium sheet lead 4 through the outer lead 7 to provide constant potential for the device for repairing;
the current change is monitored in real time by the wireless current signal acquisition and data processing system 8 to reflect the degradation condition of pollutants.
In the invention, the depth of the graphite/carbon tubular anode 1 and the stainless steel mesh counter electrode 3 inserted into the soil is preferably 2-50 cm, and more preferably 10 cm; the planting depth of the repair plants 6 is preferably 2-30 cm, and more preferably 10 cm.
Aiming at the problems of single soil remediation application technology, unsatisfactory remediation effect and inevitable ecological environment threat at present, the invention provides a device and a method for strengthening soil remediation by combining plant microorganism electrochemistry from the aspects of environmental friendliness, safety and ecology, and the device and the method have the following advantages when used for soil remediation:
first, the repair effect is better. The plant, microorganism and electrochemical three-in-one repair mode is utilized to realize a relatively ideal repair effect. Specifically, the adsorption and absorption effects of plants on soil pollutants, the degradation effect of rhizosphere microorganisms on soil pollutants, and the degradation effect of electrochemically domesticated electrogenesis microorganisms on pollutants, which are generated by electronic output by using an external electrode, are combined to strengthen soil remediation;
and secondly, secondary pollution or ecological safety threat cannot be generated. The technology of the invention has the advantages of green and safety by utilizing the combined restoration of plants, microorganisms and electrochemistry, can bring landscape ecological functions while removing pollutants, accords with the concept of circular economy, and is dedicated to the sustainable development of the environment;
thirdly, the repair cost is low. The materials and devices used by the technology mainly comprise graphite/carbon anodes, stainless steel counter electrodes, green plants and devices for providing direct current weak power supplies (dry batteries can be used), microbial inoculum and chemical substances do not need to be added, large-area soil remediation can be realized within a controllable cost range, and the technology has the advantages of economy and effectiveness;
fourthly, monitoring the soil remediation condition in real time. The repairing system utilizes an electric current data acquisition system to acquire current in real time, and the change of the current can reflect the degradation condition of pollutants, the growth and metabolism condition of microorganisms and the like;
and fifthly, the method is suitable for in-situ repair. The device and the method of the invention can be conveniently applied to the large-scale remediation of the actual polluted soil without damaging the original appearance of the soil.
Example 1
The device for electrochemically enhancing soil remediation by combining plant microorganisms provided by the embodiment is shown in fig. 1.
The repairing device comprises a cuboid organic glass box body with the inner dimension of 60cm multiplied by 30cm, and the thickness is 1 cm; about 67.5kg of the soil contaminated with the tested petroleum (taken from the vicinity of the drilled oil well in the Shandong Shengli oil field) was added; adding about 15L of distilled water to keep the soil in a wet state, wherein the water content is about 22 percent, and the height of the wet soil is about 12 cm;
winding a titanium wire around the middle part of a graphite tube (the inner diameter is 10cm, the thickness is 1cm, and the height is 10cm) for a circle, extending the titanium wire to be 2cm higher than the top of the graphite tube, and winding the contact part of the titanium wire and the graphite tube by using a conductive adhesive tape to enable the titanium wire to be tightly connected; sequentially inserting the graphite tubes (totally 9) provided with the titanium wire leads into the moist soil according to the drawing shown in figure 1, uniformly distributing the graphite tubes in the box body, wherein the depth of the graphite tubes is 10cm, and the leads extending out of the titanium wires are ensured to be consistent in direction;
shearing a stainless steel net (the diameter of the mesh is 0.5mm and the aperture is 0.42mm) with the length of 48cm and the width of 10cm, surrounding the middle part of the stainless steel net by a titanium sheet (the width is 1cm) for a circle, and extending out for 2cm to be used as a lead; inserting the organic glass into wet soil (figure 1), wherein the depth is 10cm and the distance is 1cm from the organic glass box body;
planting the screened iris lanuginosa seedlings (the plant height is about 30cm, the rhizosphere length is about 10cm) which grow well and are similar in growth vigor, blade number and rhizosphere shape in the center of a graphite tube, and planting two seedlings in each graphite tube;
cutting 10 leads with the length of about 2m, wherein 9 leads are respectively connected with the titanium wire lead of each graphite pipe and the anode passage of the potentiostat with the current acquisition function, and the other lead is connected with the titanium sheet lead of the stainless steel net and the counter electrode passage of the potentiostat; the constant voltage at the two ends of the cathode and the anode is 0.7V; collecting current data in real time by using a desktop computer provided with a signal collecting system;
the device is started and then operated under the conditions of room temperature of 20-25 ℃, humidity of 45-55% RH, daily illumination for 12h, proper ventilation and operation time of 30 days, wherein the group is marked as TG.
Comparative example 1
Untreated petroleum contaminated raw soil (taken near the oil wells drilled in the Shandong Shengli oil field) was taken as a control group OS.
Comparative example 2
Setting a plant-free and voltage-free control group: about 67.5kg of the petroleum contaminated soil (taken from the vicinity of the oil well drilled in the Shandong Shengli oil field) was added to a rectangular parallelepiped plexiglass box with an internal dimension of 60cm by 30 cm; adding about 15L of distilled water to keep the soil in a wet state, wherein the water content is about 22 percent, and the height of the wet soil is about 12 cm; the graphite pipes (9 in total) are sequentially inserted into the moist soil according to the figure 1, and are uniformly distributed in the box body, and the depth is 10 cm; iris lanuginosa seedlings were not planted, and no voltage was applied, as a control CK 1.
Comparative example 3
Plant no-voltage control group was set: two iris lanugo seedlings (plant height about 30cm, rhizosphere length about 10cm) which grew well and had similar growth vigor, leaf number and rhizosphere morphology were planted in each graphite tube in comparative example 1, and the rest was kept the same as comparative example 1 without voltage application, as a control CK 2.
Comparative example 4
Setting a conductive nano magnetite adding group: in the case of the graphite tubes of example 1, 1% of conductive nano magnetite (about 8g) was uniformly added to the petroleum soil in advance, and the balance was kept the same as example 1 (iris planted, voltage applied) as a control treatment group CF.
Test example 1
The current output condition of the combined plant-microorganism-electrochemical reinforced soil remediation device is as follows:
the current output of the repair device provided in example 1(TG group) and comparative example 4(CF group) was collected in real time by using a signal collection system, the current measurement range was 0.01 to 10mA, and the accuracy was 0.01 mA. Each of the TG group and the CF group has nine passages, and the current data of each group from the counter electrode without three passages is averaged daily to obtain an average value for drawing (figure 2), wherein the darker current of the TG group is shown in the figure, TG1-3 respectively represents the current at different positions from the counter electrode, the lighter current of the CF group is shown in the figure, and CF1-3 respectively represents the current at different positions from the counter electrode;
according to fig. 2, the current of the TG group showed a tendency of increasing and then decreasing, and the current peaked at about day 10 (average current of 0.45 ± 0.12 mA); and the closer to the counter electrode, the higher the current yield, i.e. TG1> TG2> TG 3. The current generation in the system is mainly caused by microorganisms metabolizing pollutants near the anode and leading electrons out to the electrode by the electrogenesis microorganisms; the increase in current at the early stage indicates the enrichment of the electrogenic microorganisms and the metabolism of the easily degradable petroleum hydrocarbons, and the decrease in electricity at the later stage is due to the consumption of the readily available carbon source in the system. The addition of conductive nano-magnetite to the CF group was found to yield a current lower than that of the TG group in the previous period, probably because the addition of nano-magnetite disturbed the stabilization of indigenous microbial communities, which increased slowly and peaked at about 20 days (average current 0.48 ± 0.11 mA); and also exhibits higher current production at a later stage. This is probably due to the fact that the addition of magnetite reduces the internal resistance of the soil, facilitating electron transfer in the system while reducing electron losses. As with the TG group, the current of the CF group also appears to be larger the closer it is to the counter electrode, which may also be related to the internal resistance of the soil, i.e.: the closer to the counter electrode, the lower the resistance in the circuit and the greater the current.
Test example 2
Change of Total Organic Carbon (TOC) of soil pore water of combined plant-microorganism-electrochemical strengthening soil remediation device:
the Total Organic Carbon (TOC) of the pore water of the soil contains all organic carbonaceous materials that are soluble in water and can reflect the removal of contaminants in the aqueous phase. On day 15 of remediation, pore water samples of S1-9 in the reactors of example 1 and comparative examples 2-4 were collected using a soil pore water collector (membrane pore size: 0.60 μm, brand: RHIZON MOM), the TOC content of the samples was measured using a TOC analyzer, and the average value of each group of samples was plotted (FIG. 3);
according to FIG. 3, after 15 days of repair, the average pore water TOC content in the reactors of example 1 and comparative examples 2-4 is represented as CF1> CK2> CF > TG, which indicates that the addition of plants and the application of external potential promote the consumption of TOC in the pore liquid; on day 15, the TOC concentration in CK2 was reduced by 74.1mg/kg compared to CK1, which is caused by the adsorption and absorption of organic substances by the plant rhizosphere; after the external voltage of 0.7V is applied, the TOC content of the TG group is reduced by 107.1mg/kg relative to that of the CK2 group, which shows that the external potential promotes the consumption of TOC and generates current; the TOC content of the CF group is higher than that of the TG group, because the perturbation of the nano magnetite on indigenous microorganisms slows down the consumption of TOC in the early stage, and the process can be reflected by the combination of current change.
Test example 3
Removal of Total Petroleum Hydrocarbons (TPH) from soil combined with plant-microorganism-electrochemical enhanced soil remediation devices:
after the soil samples of the example 1 and the comparative examples 2-4 are repaired for 30 days, and the soil samples of the OS are subjected to freeze drying treatment at minus 60 ℃ and then are sieved by a 60-mesh sieve; weighing 2g of each group of S1-S9 (shown in figure 3) soil samples into a 50mL centrifuge tube, adding 30mL dichloromethane, carrying out vortex for 15min, carrying out ultrasonic extraction for 30min, centrifuging for 5min at 8000r, pouring the supernatant into a weighed triangular flask after removing impurities through a 0.45-micron organic filter membrane, and repeating the steps twice; after the mixture is evaporated to dryness in a constant-temperature water bath at 42 ℃, the weight of the triangular flask is weighed, and the total petroleum hydrocarbon content is obtained according to the mass difference of the triangular flask. After obtaining the total petroleum hydrocarbon content of each sample point of example 1 and comparative examples 2-4, the difference between the total petroleum hydrocarbon content and the OS is calculated, the total petroleum hydrocarbon removal amount is obtained, and the average value of the total petroleum hydrocarbon removal amount is calculated and plotted (FIG. 4).
According to the graph of FIG. 4, after 30 days of remediation, the removal amount of TPH in the reactors of the example 1 and the comparative examples 2-4 is represented as CF > TG > CK2> CK1, which shows that the combined action of plant planting, external voltage application and conductive magnetite achieves the optimal remediation effect, and the average removal amount of TPH reaches 14228 mg/kg; compared with the CK1 group, the removal amount of the TPH is increased by 4131mg/kg, which shows that the plant rhizosphere has the functions of adsorbing and absorbing petroleum hydrocarbon; after 0.7V external voltage is applied, the TPH removal amount of the TG group is increased by 5728mg/kg relative to that of the CK2 group, because the external potential application is equivalent to providing an electron acceptor which is continuous, and the electricity-generating microorganisms enrich and metabolize pollutants and generate current; the addition of the conductive nano magnetite further promotes the electron transfer in the system, thereby accelerating the removal of the soil petroleum hydrocarbon.
The above-described embodiments are preferred forms of the invention, and it should be noted that all modifications and alterations made without departing from the principles of the invention are within the scope of the invention.
Claims (5)
1. A device for strengthening soil restoration by combining plant microorganism electrochemistry is characterized by comprising a graphite/carbon tubular anode (1) and a titanium wire lead (2) connected with the graphite/carbon tubular anode, a stainless steel mesh counter electrode (3) and a titanium sheet lead (4) connected with the stainless steel mesh counter electrode, a potentiostat (5) with a real-time current acquisition function, a restoration plant (6), an outer lead (7) connected with the anode titanium wire lead (2) and the counter electrode titanium sheet lead (4) and a wireless current signal acquisition and data processing system (8), wherein the restoration plant (6) is planted in the middle of the graphite/carbon tubular anode (1);
the graphite/carbon tubular anode (1) is a carbon-based material with good conductivity, the inner diameter is 5-30 cm, and the thickness is 0.5 ∞
5cm and 2-30 cm in height;
the stainless steel mesh counter electrode (3) has mesh diameter of 0.05-0.8 mm, pore diameter of 0.05-1 mm, and length of 5E
500cm and a height of 2-50 cm;
the constant potential rectifier (5) with the real-time current acquisition function is connected with the anode titanium wire lead (2) and the counter electrode titanium sheet lead (4) through the outer lead (7) and can provide the device with a constant potential of 0.1-10V, and has 1-30 channels,
the current of each channel is collected in real time and is 0.01-5 mA, and the wireless signal transmission function is achieved.
2. The device for combined plant microbial electrochemical enhancement of soil remediation of claim 1, wherein the potentiostatic potential is 0.7V.
3. The device for the microbial electrochemical enhancement of soil remediation of claim 1, wherein the remediation plants (6) are highly tolerant or accumulative to soil contaminants and are capable of accommodating high moisture conditions in the soil electrochemical system.
4. A method of enhanced soil remediation according to any one of claims 1 to 3 including the steps of:
inserting a graphite/carbon tubular anode (1) and a titanium wire lead (2) connected with the graphite/carbon tubular anode, and inserting a stainless steel mesh counter electrode (3) and a titanium sheet lead (4) connected with the stainless steel mesh counter electrode into soil to be repaired;
planting a repairing plant (6) in the middle of the graphite/carbon tubular anode (1);
sufficient water is added to ensure that the soil is wet to reduce the resistivity of the device;
a constant potential rectifier (5) is connected with the anode titanium wire lead (2) and the counter electrode titanium sheet lead (4) through the outer lead (7) to provide constant potential for the device for repairing;
the current change is monitored in real time by using a wireless current signal acquisition and data processing system (8) to reflect the degradation condition of pollutants.
5. The method according to claim 4, characterized in that the graphite/carbon tubular anode (1) and the stainless steel mesh counter electrode (3) are inserted into the soil to a depth of 2-50 cm, and the depth of the plant (6) is 2-30 cm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011229336.7A CN112474773B (en) | 2020-11-06 | 2020-11-06 | Device and method for strengthening soil remediation by combining plant microorganism electrochemistry and application |
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| CN202011229336.7A CN112474773B (en) | 2020-11-06 | 2020-11-06 | Device and method for strengthening soil remediation by combining plant microorganism electrochemistry and application |
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| CN114433619B (en) * | 2022-02-18 | 2022-10-21 | 南开大学 | Self-assembled electrode for soil carbon emission reduction and application thereof |
| CN114733905A (en) * | 2022-05-06 | 2022-07-12 | 南开大学 | Soil remediation system |
| CN115055511B (en) * | 2022-06-15 | 2023-06-27 | 中南林业科技大学 | Device for repairing heavy metal contaminated soil by using bipolar biochar to strengthen microorganisms and plants |
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