CN115636526A - A Method for the Transfer and Transformation of Organic Pollutants Based on Fe Redox Enhancement - Google Patents

Abstract

The invention discloses a method for migration and conversion of organic pollutants based on Fe redox enhancement, and belongs to the field of environmental pollution monitoring and restoration. The method comprises the steps of adding microorganisms and a carbon source into a medium containing organic pollutants and iron, and sequentially carrying out anaerobic culture and aerobic culture; the microorganism comprises Shewanella Oneidensis MR-1 Shewanella, is purchased from China center for type culture Collection, and has a collection number of CCTCC AB 2013238; the method provided by the invention regulates and controls the Fe redox process by Fe and microorganisms and providing microorganism growth conditions, so as to strengthen the migration and transformation processes of organic pollutants, and has great application potential in the fields of regulating and controlling the migration and transformation of organic pollutants in medium environments such as field soil, water and the like and controlling the diffusion of organic pollutants.

Description

A method for the migration and transformation of organic pollutants based on Fe redox enhancement

technical field

The invention relates to a method for the migration and transformation of organic pollutants based on Fe redox enhancement, which belongs to the field of environmental pollution migration and transformation, and is mainly used for monitoring and repairing organic pollutants in multi-media environments such as soil-water.

Background technique

Persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons are widely detected pollutants in soil, sediment, water and other environments, mainly from human production activities, including petrochemical production, fossil Waste emissions from incomplete combustion of fuel, etc. Persistent organic pollutants in the environment have carcinogenic, teratogenic and mutagenic effects, posing a potential threat to human health. The migration and transformation of persistent organic pollutants and pollution monitoring are important environmental issues related to human health and sustainable development of ecosystems.

The migration and transformation of persistent organic pollutants involves physical, chemical and microbial processes, but the single physical treatment has the characteristics of low migration and transformation efficiency, high cost of chemical oxidation, and low microbial transformation and degradation activity.

The prior art of Chinese Patent Application Publication No. CN112872012A discloses a method for synergistically removing soil petroleum hydrocarbons through electrochemically enhanced persulfate oxidation. In this method, under the action of an electric field, the surfactant is injected into the polluted soil in the form of cathodic transport. When the pollutants in the soil are migrated and enriched in the advanced oxidation filler area, the inert anode is taken out and the Fe anode is inserted in situ. The migration situation moves from the inert cathode to the anode, and then the oxidative degradation continues until the pollutant degradation reaches the required value. The invention has universal applicability, is applicable to various types of organic polluted soils and sites, and is also applicable to low-permeability and barren soils. However, this method uses electric drive to enhance the migration of pollutants and chemical oxidation conversion and degradation, which is costly and energy-consuming, and is difficult to apply directly to in-situ treatment of large areas of polluted soil.

Contents of the invention

1. The problem to be solved

Aiming at the disadvantages of low migration and conversion efficiency of organic pollutants, high cost, and high energy consumption in the prior art, the present invention provides a method for the migration and conversion of organic pollutants based on Fe redox enhancement, by using microorganisms to regulate the oxidation of Fe Reduced state, which increases the dissolution and migration ability of organic pollutants, and is further oxidized and degraded ^by the active oxygen hydrogen peroxide H ₂ O ₂ and hydroxyl radical OH generated in the aerobic culture of microorganisms, thereby realizing the enhanced migration and transformation of organic pollutants .

2. Technical solution

A method for the migration and conversion of organic pollutants based on Fe redox enhancement, adding microorganisms and carbon sources to a medium containing organic pollutants and iron, and performing the steps of anaerobic cultivation and aerobic cultivation in sequence; the microorganisms include Shewanella Oneidensis MR-1 Shewanella genus, purchased from China Center for Type Culture Collection, preservation number CCTCCAB 2013238; the medium containing organic pollutants and iron includes adding iron or iron-containing medium to the medium containing organic pollutants. medium, or the medium formed by adding organic pollutants to the ferrous medium, or the ferrous medium polluted by organic pollutants. The Shewanella Oneidensis MR-1 is a facultative anaerobic bacterium of the genus Shewanella, which can anaerobically reduce Fe(III) to Fe(II).

Preferably, the iron-containing medium includes one or more of iron-containing soil, naturally occurring or artificially synthesized iron-containing minerals, or a mixed system composed of artificially added iron-containing compounds. Among them, the iron-containing minerals may be goethite (generally 30-63% iron content), hematite, lepidocerite, ferrihydrite, magnetite and the like.

Preferably, the organic pollutants include one or more of polycyclic aromatic hydrocarbons, chlorinated hydrocarbons, petroleum hydrocarbons, benzene series and the like. Among them, polycyclic aromatic hydrocarbons include phenanthrene and pyrene.

Preferably, the following steps are included:

S1 uses sterilized nutrient broth medium to cultivate and multiply the Shewanella Oneidensis MR-1 Shewanella genus, and then adjust the number of bacteria or the density of bacteria to reach a specific value;

S2 adds iron-containing compounds to the medium containing organic pollutants, and then adds to the sterilized inorganic salt medium, followed by inoculating the Shewanella Oneidensis MR-1 Shewanella genus and carbon source described in step S1; or

Adding a sterilized inorganic salt medium to the iron-containing medium, followed by inoculating the ShewanellaOneidensis MR-1 Shewanella genus and carbon source in the step S1, and then adding organic pollutants to mix; or

Adding sterilized inorganic salt medium to the iron-containing medium contaminated by organic pollutants, followed by inoculation of Shewanella Oneidensis MR-1 Shewanella genus and carbon source described in step S1;

S3 anaerobic culture: the mixed system obtained in the step S2 is ventilated with nitrogen to remove oxygen, sealed and cultured under anaerobic conditions; during the anaerobic culture process, Shewanella Oneidensis MR-1 reduces iron;

S4 aerobic culture: after the anaerobic culture in step S3, the reaction system is transformed into aerobic culture with shaking; during the aerobic culture, Shewanella Oneidensis MR-1 produces H ₂ O ₂ , Further generate OH; OH attacks the surface ^{of the} medium to adsorb or dissolve organic pollutants to strengthen the degradation and transformation of organic pollutants;

S5 repeats the steps of anaerobic culture and aerobic culture of S3 and S4 in sequence, and circulates the culture; until the conversion and degradation of organic pollutants in the system is complete;

S6 supplemented carbon source during anaerobic culture and aerobic culture. The carbon source is properly supplemented according to the consumption situation.

The method of the present invention uses Shewanella Oneidensis MR-1 to regulate the reduction and oxidation of the Fe-containing medium during the anaerobic/aerobic respiration process to generate Fe(II) and hydrogen peroxide H ₂ O ₂ . On the one hand, the iron-containing medium The reduction and dissolution of the medium changes the state of the medium, releasing the organic pollutants adsorbed and fixed on the surface or inside of the medium into the surrounding environment, which leads to the enhancement of the migration activity of the organic pollutants; on the other hand, the Fe generated during the reduction and oxidation of the Fe-containing medium (II) and hydrogen peroxide H ₂ O ₂ can further react to generate hydroxyl radical ^· OH, ^· OH attacks the surface of the medium to adsorb or dissolve organic pollutants, thereby strengthening the degradation and conversion of organic pollutants.

Preferably, the propagation conditions of the Shewanella Oneidensis MR-1 genus include: aerobic culture, inoculating an appropriate amount of bacterial liquid in a sterilized nutrient broth medium, and cultivating overnight at 30°C and 160rpm in the dark; Wash twice with sterile pH 7.0 0.1M phosphate buffer, and adjust the bacterial density to OD ₆₀₀ =1.20.

Preferably, the solid-to-liquid mass ratio of the iron-containing medium or the iron-containing medium contaminated by organic pollutants to the inorganic salt medium in the reaction system of steps S2 to S4 is 1: (20 to 100), Shewanella Oneidensis MR-1 The OD ₆₀₀ of the genus after inoculation and dilution is not less than 0.05.

Preferably, in the step S3, the anaerobic culture is passed through nitrogen for no less than 15 minutes to achieve the purpose of completely removing oxygen in the system; the anaerobic culture time is no less than 24 hours to fully reduce and generate Fe(II).

Preferably, the aerobic cultivation time in the step S4 is 3-8 hours. Aerobic culture generates reactive oxygen species hydrogen peroxide H ₂ O ₂ and hydroxyl radical ^· OH.

Preferably, the total number of cycle culture in step S5 is not less than 3 times.

Preferably, the carbon source in the step S2 is selected from one or more of lactate, citrate, pyruvate, etc.; the concentration is 10-500 mM.

3. Beneficial effect

Compared with the prior art, the beneficial effects of the present invention are:

(1) In the present invention, for organic pollutants, especially polycyclic aromatic hydrocarbons, adopt Shewanella OneidensisMR-1 Shewanella genus and iron synergy to carry out anaerobic culture (reduction process) and aerobic culture (oxidation process) that cycle repeatedly successively process) step, which can generate Fe(III)/Fe(II) cycle under iron redox conditions. At the same time, Shewanella OneidensisMR-1 Shewanella can generate H ₂ O ₂ under aerobic conditions. The above-mentioned anaerobic and The aerobic process has a significant impact on the migration and transformation of organic pollutants; the interaction between Fe(II) and H ₂ O ₂ can generate active oxygen such ^as OH to efficiently oxidize organic pollutants; Fe is the fourth The large element, Fe, is rich in soil and water media, and its redox cycle is related to a variety of biogeochemical processes, and plays an important role in the migration and transformation of pollutants; in the environment of soil-groundwater redox fluctuations, microorganisms and Iron-mineral interactions have a significant effect on ROS generation.

(2) For iron-containing media polluted by organic pollutants such as iron-containing minerals, the present invention regulates the reduction and oxidation of iron in iron-containing minerals by utilizing ShewanellaOneidensis MR-1 Shewanella, changes the mineral state, and makes organic pollution The substances are released with the reduction and dissolution of iron-containing minerals and other media, and are further oxidized and degraded by active oxygen, which realizes the purpose of strengthening the migration and transformation of organic pollutants; the oxidation-reduction process of iron-containing minerals has outstanding effects on the migration and transformation of organic pollutants. This may be due to the fact that iron-containing minerals are the adsorption and fixation medium of organic pollutants, and regulate the adsorption and dissolution state of organic pollutants through their own valence changes, thereby affecting and changing the migration activity of organic pollutants; It can stimulate and promote the growth and metabolism of microorganisms, and promote the migration and transformation of organic pollutants.

Description of drawings

Fig. 1 shows the characteristics of the migration and transformation of polycyclic aromatic hydrocarbons phenanthrene and pyrene under the anaerobic/aerobic cycle of Shewanella Oneidensis MR-1 under the regulation of Fe-containing minerals by Shewanella Oneidensis MR-1 in Example 1 of the present invention: a, c: Fe-containing needles Transformation of phenanthrene and pyrene in iron ore system; b, d: Transformation of phenanthrene and pyrene in kaolinite control system without Fe;

Fig. 2 is the concentration that the Fe goethite system generates Fe(II) when the anaerobic/aerobic cycle anaerobic culture finishes in the embodiment of the present invention 2;

Figure ₃ is the characteristics of the concentration change of H2O2 at the end of anaerobic/aerobic cycle aerobic culture in Example ₂ of the present invention: a: Fe-containing goethite system; b: Fe-free kaolinite control system;

Figure 4 is the concentration characteristics ^of OH generated at the end of the fourth anaerobic/aerobic cycle aerobic culture in Example 2 of the present invention, a: Fe-containing goethite system; b: Fe-free kaolinite control system.

Detailed ways

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention; the term "and/or" used herein includes one or more related listed Any and all combinations of items.

Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

Concentrations, amounts, and other numerical data may be presented herein in a range format. It should be understood that such range format is used for convenience and brevity only, and should be construed flexibly to include not only the numbers expressly recited as the limits of the range, but also to encompass all individual values or subranges within said range, It is as if each value and subrange were expressly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted to include not only the expressly recited limit of 1 to about 4.5, but also include individual numbers (such as 2, 3, 4) and subranges (such as 1 to 3, 2 to 4 etc.). The same principle applies to ranges reciting only one numerical value, such as "less than about 4.5", which should be construed to include all such values and ranges. Moreover, such an interpretation should apply regardless of the breadth of the range or features described.

The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be pointed out that, if there are any processes in the following that are not specifically described in detail, those skilled in the art can realize or understand with reference to the prior art. The reagents or instruments used were not indicated by the manufacturer, and they were regarded as conventional products that can be purchased from the market.

As an example, in the following examples, goethite is used as Fe-containing mineral medium, kaolinite is Fe-free mineral medium, phenanthrene and pyrene in polycyclic aromatic hydrocarbons are selected as representative organic pollutants, and Shewanella Oneidensis MR-1 Greek Varella spp. for experiments. The strain is an Fe-reducing bacterium, purchased from the China Center for Type Culture Collection with the preservation number CCTCCAB2013238, and is a Gram-negative bacterium.

Example 1

1. Preparation of PAH Contaminated Mineral Media

Mixing polycyclic aromatic hydrocarbons with minerals includes the following steps, specifically:

Weigh 10g of minerals (goethite, iron content about 60%; kaolinite, iron-free) into a 100mL glass beaker, add 10mL of acetone-prepared phenanthrene and pyrene mixture, shake gently, and then let stand In a fume hood, wait until the acetone is completely volatilized to obtain minerals contaminated with phenanthrene and pyrene. The contents of phenanthrene and pyrene in polluted minerals are respectively:

Goethite: phenanthrene, 346±25 μg g ^-1 ; pyrene, 328±11 μg g ^-1 ; ΣPAHs, 674±27 μg g ^-1 .

Kaolinite: phenanthrene, 258±31 μg g ^-1 ; pyrene, 238±17 μg g ^-1 ; ΣPAHs, 495±36 μg g ^-1 .

Minerals were ground and passed through a 60-mesh sieve and stored in brown glass reagent bottles.

2. Cultivation and propagation of strains

Activation and propagation of the strain, the strain is Shewanella Oneidensis MR-1 Shewanella genus, purchased from China Center for Type Culture Collection, preservation number CCTCC AB 2013238. The bacteria is a typical metal-reducing bacteria, which can reduce Fe(III) to Fe(II). Activation and multiplication include the following steps, specifically:

Thaw the degrading bacteria (Shewanella Oneidensis MR-1 Shewanella spp.) stored in glycerol at -80°C, inoculate them in sterilized nutrient broth medium, the inoculation ratio is 0.2mL of preservation solution per 100mL of medium, Then culture overnight at 30°C, 160rpm aerobic and dark. After the strain grows to the logarithmic phase, take it out, transfer it to a sterilized centrifuge tube at 5000rpm and centrifuge to collect the lower layer of bacteria, and then use sterilized phosphate buffer (pH7.0) The supernatant was used twice, and after resuspension, the bacterial density was adjusted so that OD ₆₀₀ =1.20.

3. Microorganisms regulate the reduction and oxidation of Fe-containing media to enhance the migration and transformation of polycyclic aromatic hydrocarbons phenanthrene and pyrene

The reduction and oxidation of Fe-containing media regulated by microorganisms enhance the migration and transformation of polycyclic aromatic hydrocarbons phenanthrene and pyrene, including the following steps, specifically:

MR-1+carbon source group: Weigh 0.6g of the two contaminated minerals into a 50mL glass centrifuge tube, add 28mL of sterilized inorganic salt medium, and then inoculate 2mL of the prepared Shewanella Oneidensis MR-1 Shewanella bacterium solution (OD ₆₀₀ =1.20), 0.12 mL of 60% lactate was added as a carbon source (final concentration 20 mM). In this experiment, the solid-to-liquid ratio was 1:50 (1:20 to 1:100 is acceptable), and the bacterial density OD ₆₀₀ was not less than 0.05 after inoculation.

MR-1 group: At the same time, set the inoculated strain but no lactate carbon source treatment (control group 1, MR-1), to determine whether Shewanella Oneidensis MR-1 Shewanella can use PAHs as the sole carbon source growth metabolism.

CK group: The experiment also set up the treatment of not inoculating Shewanella Oneidensis MR-1 Shewanella spp. (control group 2, CK) to exclude the non-biologically regulated degradation of PAHs in the mineral system.

The above-mentioned experimental system was fed with N ₂ for 15 minutes to remove oxygen in the solution, then placed at 28°C for static anaerobic culture for 40 hours, and then aerobic cultured for 8 hours under shaking conditions, which was an anaerobic/aerobic culture cycle.

During this experiment, the anaerobic/aerobic culture cycle was repeated 4 times.

At the end of each anaerobic/aerobic culture stage, the sample solution was drawn to measure the concentration of phenanthrene and pyrene, and the migration and transformation characteristics of phenanthrene and pyrene were analyzed. The sample liquid was extracted with an organic solvent, and the content of remaining phenanthrene and pyrene in the extract was determined by high performance liquid chromatography (HPLC), and the conversion kinetics curve of phenanthrene and pyrene (Fig. 1) was drawn, and the conversion rate of phenanthrene and pyrene was calculated. The results showed that after 4 anaerobic/aerobic cycle cultivation (192h), 60% of phenanthrene and 48.6% of pyrene were observed to be degraded and transformed in the goethite system with MR-1+ carbon source (Figure 1a,c) . Although phenanthrene and pyrene were also degraded in the control treatment, the conversion rate of phenanthrene and pyrene was significantly increased in the MR-1+ carbon source treatment, but there was no difference in the degradation and conversion of phenanthrene and pyrene in the MR-1 treatment alone compared with the control. In the kaolinite system, 38.1% of phenanthrene and 37.2% of pyrene were observed to be degraded and converted by MR-1+ carbon source treatment (Fig. 1b, d), MR-1+ carbon source treatment, MR-1 treatment and control treatment In contrast, there was no significant difference in PAHs transformation, even lower than that of control group 2 treatment (Fig. 1b). The above results revealed that the strain MR-1 could not use PAHs as the sole carbon source to convert PAHs, nor could it co-metabolize PAHs with lactate. Only under the coexistence of Fe and carbon source can the strain MR-1 regulate the enhanced migration and transformation of PAHs under aerobic/anaerobic cycle conditions in Fe-containing mineral media.

Example 2

(1) Microbial regulation of Fe reduction activity in Fe-containing mineral media

The research on the reduction activity of Fe-containing mineral media by microorganisms, including the following steps, specifically:

Adopt the method of Example 1 to construct the anaerobic/aerobic culture system of microorganism-mineral (Shewanella Oneidensis MR-1+carbon source-mineral) migration conversion polycyclic aromatic hydrocarbons, draw sample liquid and measure at the end of each anaerobic culture stage Fe(II) content, analysis of Fe reduction activity. The concentration of Fe(II) in the system at the end of anaerobic culture was determined by phenanthrozine. Fe(II) forms a red complex with phenanthroxine, which has a maximum absorption peak at 562nm. Draw 0.5mL of sample solution into a 2mL centrifuge tube, add 0.5mL of 2mM phenanthrozine solution, react for 5min and then make it to 1.5mL, then centrifuge at 6000r/min for 5min, and the Fe(II) in the supernatant is measured by UV-Vis spectrophotometry It is measured colorimetrically at a wavelength of 562nm, and the molar absorptivity is 27900M ^-1 cm ^-1 . The results show (Fig. 2), in the goethite system (control group 2) without Shewanella Oneidensis MR-1 and carbon source addition, basically no Fe(II) was detected; while the treatment of inoculated MR-1 (MR-1 and MR-1+carbon source) were observed to form Fe(II), and the concentration of Fe(II) was 0.6-9.0μM. It was proved that under anaerobic culture conditions, goethite could be reductively dissolved into Fe(II) by the strain MR-1.

(2) Microorganisms regulate the generation of active substances in the oxidation of Fe-containing mineral media

The research on microbial regulation of the formation of oxidative active substances in Fe-containing mineral media includes the following steps, specifically:

Using the method of Example 1 to construct an anaerobic/aerobic culture system in which microorganisms-minerals (Shewanella Oneidensis MR-1+carbon source-minerals) migrate and convert polycyclic aromatic hydrocarbons, draw sample liquid for determination at the end of each aerobic culture stage Hydrogen peroxide H ₂ O ₂ content, a sample was drawn at the end of the last aerobic incubation period to analyze the hydroxyl radical ^· OH content. The specific method is as follows:

(1) Determination of hydrogen peroxide H ₂ O ₂ content: the specific process is: use the horseradish peroxidase method to measure the H ₂ O ₂ generated in the system. Draw 0.5mL of the sample solution into a 2mL centrifuge tube, add 0.1mL of 1mg/mL horseradish peroxidase, then add 0.5mL of 10mM ABTS solution, react for 5min, then dilute to 1.5mL, and centrifuge the mixture at 6000r/min for 5min . H ₂ O ₂ oxidizes ABTS under the catalysis of horseradish peroxidase to produce green ABTS ^·+ . After the sample was centrifuged, ABTS ^·+ in the supernatant was measured by colorimetry at 415nm, and the molar absorbance was 34000M ^-1 cm ^-1 . The stoichiometric ratio of H ₂ O ₂ to ABTS ^·+ is 2, and the concentration of ABTS ^·+ is divided by the coefficient 2 to obtain the concentration of H ₂ O ₂ generated in the solution. The results show (Fig. 3): During the aerobic culture stage, the generation of H ₂ O ₂ can be detected in both goethite and kaolinite systems. Under CK treatment and MR-1 treatment, only a very small amount of H ₂ O ₂ generation (<0.3 μM) was detected, revealing that in the case of aseptic or inoculation but no external carbon source, the generation of H ₂ O ₂ reactive oxygen species The cumulative production is extremely low, which also reflects little microbial activity. In the treatment of MR-1+ carbon source, the two mineral systems can generate higher concentration of H ₂ O ₂ , and the cumulative concentration reached the highest (~40μM) after the second aerobic stage culture, and in the third and 4 stage H ₂ O ₂ production concentration decreased sharply (~0.64μM), presumably because of the low concentration of added carbon source lactate (20mM), after two anaerobic/aerobic cycle culture (96h) carbon The depletion of the source leads to the reduction of aerobic respiration activity and the decrease of H ₂ O ₂ production in the subsequent cultivation process.

(2) Determination of hydroxyl radical ^· OH content: the specific process is: use coumarin as a probe to measure the concentration of ^· OH generated at the end of aerobic culture in the system. Mix 0.5mL sample liquid with 0.5mL 2mM coumarin, incubate aerobically for 2h, and add 0.5mL methanol at the end of the culture to terminate the reaction. Then the mixture was centrifuged at 6000r/min for 5min, and the supernatant was passed through a 0.22μm filter membrane, and the oxidized product 7-hydroxycoumarin was determined by HPLC-fluorescence detection system. The concentration of 7-hydroxycoumarin was calculated by the standard curve of 0.005-1 μM, and the detection limit of this method was 0.0032 μM. The resulting ^· OH concentration was calculated by dividing the 7-hydroxycoumarin concentration by a factor of 14.5%. The results showed ( FIG. 4 ): ^· OH was detected in all treatments, and its content was between 0.008 μM and 0.54 μM. The formation of ^· OH in the control treatment revealed the possible abiotic transformation of mineral system pollutants. However, the decrease of phenanthrene and pyrene concentration in CK treatment in this study confirmed the abiotic transformation degradation of PAHs in mineral system. Among the microbial treatments, the treatment only inoculated with MR-1 produced the lowest ^· OH production, even less than that of the control treatment. This is because the microbial aerobic respiration activity of the strain MR-1 is very low in the absence of additional carbon sources, which is consistent with the previous results of low Fe(II) and H ₂ O ₂ production activities, resulting in the inability ^of MR-1 to regulate OH Formation, and affect the formation of abiotic factors ^· OH. In the presence of carbon sources, MR-1 regulates the generation of a large amount ^of OH, which is related to the reduction of anaerobic respiration to Fe(II) and the generation of H ₂ O ₂ in aerobic respiration, and the two react ^to form OH, thereby transforming minerals System phenanthrene and pyrene and other organic pollutants.

The above results indicated that microbial regulation of the Fe(III)/Fe(II) reduction and oxidation process could lead to the reductive dissolution of Fe-containing mineral media and the release of organic pollutants, which were stimulated by reactive oxygen species H ₂ O ₂ and ^· OH attack to transform and degrade, so as to realize the enhanced migration and transformation of organic pollutants. Experiments show that the redox process based on Fe has an important impact on the migration and transformation process and pollution distribution of organic pollutants in environmental media such as soil-water, and has good application potential in the control of organic pollution on site.

The above examples are only preferred implementations of the present invention, and are only used to explain the present invention, rather than limit the present invention. Changes, replacements, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention shall belong to the present invention. protection scope of the invention.

Claims (10)

1. A method for the migration and conversion of organic pollutants based on Fe redox enhancement, characterized in that, adding microorganisms and carbon sources to the medium containing organic pollutants and iron, followed by the steps of anaerobic cultivation and aerobic cultivation; The microorganisms include Shewanella Oneidensis MR-1 Shewanella genus, purchased from the China Center for Type Culture Collection, preservation number CCTCC AB 2013238; the medium containing organic pollutants and iron includes adding to the medium containing organic pollutants The medium formed by iron or ferrous medium, or the medium formed by adding organic pollutants to the ferrous medium, or the ferrous medium polluted by organic pollutants. 2. The method for the migration and conversion of organic pollutants based on Fe redox enhancement according to claim 1, wherein the iron-containing medium includes iron-containing soil, naturally formed or artificially synthesized iron-containing minerals, or artificial One or more of the mixed systems composed of external sources of iron-containing compounds. 3. the method for the migration and conversion of organic pollutants based on Fe redox strengthening according to claim 2, is characterized in that, described organic pollutants comprise polycyclic aromatic hydrocarbons, chlorinated hydrocarbons, petroleum hydrocarbons, benzene series etc. one or more. 4. the method for the migration and conversion of organic pollutants based on Fe redox strengthening according to claim 1, is characterized in that, comprises the following steps: S1 uses sterilized nutrient broth medium to cultivate and multiply the Shewanella Oneidensis MR-1 Shewanella genus, and then adjust the number of bacteria or the density of bacteria to reach a specific value; S2 adds iron-containing compounds to the medium containing organic pollutants, and then adds to the sterilized inorganic salt medium, followed by inoculating the Shewanella Oneidensis MR-1 Shewanella genus and carbon source described in step S1; or Adding a sterilized inorganic salt medium to the iron-containing medium, followed by inoculating the ShewanellaOneidensis MR-1 Shewanella genus and carbon source in the step S1, and then adding organic pollutants to mix; or Adding sterilized inorganic salt medium to the iron-containing medium contaminated by organic pollutants, followed by inoculation of Shewanella Oneidensis MR-1 Shewanella genus and carbon source described in step S1; S3 anaerobic culture: the mixed system obtained in the step S2 is ventilated with nitrogen to remove oxygen, and cultured under anaerobic conditions after sealing; S4 aerobic culture: after the anaerobic culture in step S3 is completed, the reaction system is converted to culture under aerobic conditions of vibration; S5 repeats the above-mentioned steps of S3 and S4 anaerobic cultivation and aerobic cultivation successively, and circulates cultivation; S6 supplemented carbon source during anaerobic culture and aerobic culture. 5. the method for the migration and conversion of organic pollutants based on Fe redox strengthening according to claim 4, is characterized in that, described Shewanella Oneidensis MR-1 Shewanella propagation condition comprises: aerobic culture, after killing Inoculate an appropriate amount of bacterial solution into the bacterial nutrient broth medium, and culture overnight at 30°C and 160 rpm in the dark; wash twice with sterilized pH 7.0 0.1M phosphate buffer, and adjust the bacterial density to OD ₆₀₀ =1.20. 6. The method for the migration and conversion of organic pollutants based on Fe redox enhancement according to claim 4, characterized in that, the step S2-S4 reaction system contains iron-containing medium or the iron-containing medium polluted by organic pollutants and inorganic The solid-to-liquid mass ratio of the salt medium is 1: (20-100), and the OD ₆₀₀ after inoculation and dilution of Shewanella Oneidensis MR-1 is not less than 0.05. 7. The method for the migration and transformation of organic pollutants based on Fe redox enhancement according to claim 4, characterized in that, in the step S3, the nitrogen gas flow time for anaerobic cultivation is not less than 15min, and the anaerobic cultivation time is not less than 24h. 8. The method for the migration and transformation of organic pollutants based on Fe redox enhancement according to claim 4, characterized in that the aerobic cultivation time in the step S4 is 3-8 hours. 9 . The method for the migration and transformation of organic pollutants based on Fe redox enhancement according to any one of claims 4 to 8 , characterized in that the total number of cycle cultures in the step S5 is not less than 3 times. 10. The method for the migration and transformation of organic pollutants based on Fe redox enhancement according to claim 4, characterized in that in the step S2, the carbon source is selected from one of lactate, citrate, and pyruvate Or several; the concentration is 10-500mM.

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