Method for removing chlorinated organic pollutants in water by using sulfidized nano zero-valent iron and methanogenic archaea coupling system

Abstract

The application discloses a method for removing chlorinated organic pollutants in water by using a sulfidized nano zero-valent iron and methanogen coupling system ， The method constructs a microorganism-material coupling reaction system to degrade and treat the chlorinated organic pollutants in water. The method uses the sulfidized nano zero-valent iron and the methanogen to construct the microorganism-material coupling reaction system for degrading the chlorinated organic pollutants, can realize efficient removal of the chlorinated organic pollutants, can significantly improve the pollutant removal efficiency and reaction sustainability, can effectively improve the utilization rate of the sulfidized nano zero-valent iron, prolong the service life of the sulfidized nano zero-valent iron, has high use value and good application prospect.

Description

Technical Field

[0001] This invention belongs to the technical field of groundwater pollution remediation and environmental functional materials, and relates to a method for removing chlorinated organic pollutants in water using a coupling system of sulfide nano-zero valent iron and methanogenic archaea. Background Technology

[0002] Chlorinated organic pollutants (COPs) are a typical class of persistent organic pollutants, widely originating from industrial production processes such as pesticides, pharmaceuticals, dyes, and wood preservatives. They are characterized by high toxicity, poor degradation, and easy migration and accumulation in groundwater. For example, p-chlorophenol is frequently detected in groundwater, posing a potential threat to ecosystems and human health. Therefore, developing efficient and stable groundwater remediation technologies for COPs is of great significance.

[0003] Nano-zero-valent iron (NZVI) is widely used for the removal of chlorinated organic pollutants from groundwater due to its large specific surface area, strong reducing power, and good environmental compatibility. However, in practical applications, NZVI particles are prone to aggregation and side reactions with water or dissolved oxygen. More importantly, a passivation layer composed of Fe(II) / Fe(III) oxides or hydroxides easily forms on its surface during the reaction process. This passivation layer hinders electron transfer and covers active sites, leading to a rapid decline in the material's reactivity and severely limiting its long-term application effectiveness. To improve these problems, researchers have proposed various modification strategies, such as surface modification, bimetallic doping, and sulfidation modification. Among them, sulfided nano-zero-valent iron (S-NZVI), by introducing a FeS structural layer on the material surface, can reduce the water's reaction with Fe to a certain extent. 0 The core undergoes direct corrosion, slowing down the passivation process and improving the material's selectivity for target contaminants. However, even after sulfidation modification, Fe... 0 The base material inevitably undergoes surface passivation during long-term reactions, and its reaction lifespan remains limited.

[0004] For the reasons stated above, this invention is proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for removing chlorinated organic pollutants in water by using a coupling system of sulfided nano-zero valent iron and methanogenic archaea. By constructing a microbial-material coupling reaction system using sulfided nano-zero valent iron and methanogenic archaea, in-situ regeneration and continuous reaction of sulfided nano-zero valent iron can be achieved, thereby significantly improving the pollutant removal efficiency and the utilization rate of nano-zero valent iron.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for removing chlorinated organic pollutants from water using a coupling system of sulfide nano-zero-valent iron and methanogenic archaea, wherein the method involves adding sulfide nano-zero-valent iron and methanogenic archaea to the water containing chlorinated organic pollutants. ， A microbial-material coupled reaction system was constructed to degrade chlorinated organic pollutants in water.

[0007] Furthermore, in the above method, the amount of sulfide nano-zero valent iron added in the microbial-material coupling reaction system is 0.1 g / L to 2.0 g / L.

[0008] Furthermore, in the above method, the amount of sulfide nano-zero valent iron added in the microbial-material coupling reaction system is 0.5 g / L to 1.5 g / L.

[0009] Further, in the above method, the molar ratio of sulfur to iron in the sulfide nano-zero valent iron is 1:30; the sulfide nano-zero valent iron is prepared by reducing iron salt and thiosulfate with sodium borohydride; the preparation method of the sulfide nano-zero valent iron includes the following steps: mixing thiosulfate and sodium borohydride to prepare a mixed solution, adding the mixed solution dropwise to the iron salt solution under nitrogen atmosphere and stirring to carry out the reduction reaction, continuing stirring after the addition is completed, magnetic separation, washing, and drying to obtain sulfide nano-zero valent iron.

[0010] Further, in the above method, the thiosulfate is Na2S2O3·5H2O; the concentration of sodium borohydride in the mixed solution is 0.2M; the dropping rate of the mixed solution is 7.5mL / min; the iron salt solution is ferric chloride solution; the concentration of the iron salt solution is 0.05M; the washing is performed by washing 2-3 times with anhydrous ethanol; and the drying is performed by drying under vacuum at 60℃ for 15h.

[0011] Furthermore, in the above method, the inoculation amount of methanogenic archaea in the microbial-material coupling reaction system is 2% to 20% (v / v).

[0012] Furthermore, in the above method, the inoculation amount of methanogenic archaea in the microbial-material coupling reaction system is 5% to 15% (v / v).

[0013] Furthermore, in the above method, the methanogenic archaea is *Pasteurella multocida*, named as follows: Methanosarcina barkeri DSM 800.

[0014] In the above method, the chlorinated organic pollutant water body is groundwater containing chlorinated organic pollutants; the initial concentration of chlorinated organic pollutants in the chlorinated organic pollutant water body is ≤10mg / L; and the chlorinated organic pollutant is p-chlorophenol.

[0015] Furthermore, in the above method, the degradation treatment is carried out under anaerobic conditions; the degradation treatment is carried out at a temperature of 37±1℃ and a rotation speed of 150rpm; and the degradation treatment time is 15 days.

[0016] Compared with the prior art, the advantages of the present invention are as follows: To address the shortcomings of existing remediation methods based on nano-zero-valent iron materials, such as easy passivation of material surfaces, rapid decay of reactivity, and low utilization rate, which lead to low removal efficiency of chlorinated organic pollutants and easy secondary pollution, this invention creatively proposes a method for removing chlorinated organic pollutants from water using a coupling system of sulfide nano-zero-valent iron and methanogenic archaea. This method involves adding sulfide nano-zero-valent iron and methanogenic archaea to the water containing chlorinated organic pollutants. ， A microbial-material coupled reaction system was constructed to degrade chlorinated organic pollutants in water. In this invention, sulfide nano-zero-valent iron was used as the reactant, and methanogenic archaea with strong reducing capabilities were introduced to construct a synergistic system. Through the coupling of material reduction and microbial metabolic processes, efficient removal of chlorinated organic pollutants was achieved. Specifically, in the initial stage of the reaction, sulfide nano-zero-valent iron rapidly degraded chlorinated organic pollutants due to its strong reducing properties, while simultaneously undergoing a corrosion reaction in the aquatic environment and releasing electrons and hydrogen. As the reaction proceeds, a passivation layer mainly composed of Fe(III) oxides or hydroxides gradually forms on the material surface, leading to a decrease in reactivity. At this point, the methanogenic archaea, during their metabolism, can utilize the hydrogen generated in the system and participate in the electron transfer process through their intracellular and extracellular low redox potential electron carriers, thereby reducing Fe(III) on the material surface to Fe(II), promoting the transformation or removal of the passivation layer, and re-exposing active Fe. 0 / Fe 2+This invention establishes a site for the in-situ regeneration and continuous reaction of sulfide nano-zero-valent iron. Simultaneously, the interaction between methanogenic archaea and sulfide nano-zero-valent iron creates stable electron transport channels within the system, significantly improving interfacial electron transport efficiency. Furthermore, the metabolic processes of methanogenic archaea can directly or indirectly participate in the transformation and degradation of pollutants, forming a synergistic effect with the reduction process of sulfide nano-zero-valent iron. Through these multiple mechanisms, a self-sustaining reaction system coupled with "material reduction—microbial metabolism—iron redox cycle" is constructed, effectively alleviating the passivation and deactivation problem of sulfide nano-zero-valent iron. It also significantly improves pollutant removal efficiency and reaction sustainability, effectively enhances the utilization rate of sulfide nano-zero-valent iron, and extends its service life. This invention provides a new strategy for the efficient and sustainable remediation of recalcitrant organic pollutants in groundwater.

[0017] Compared with conventional remediation methods, this invention utilizes a coupling system of sulfide nano-zero-valent iron and methanogenic archaea to remove chlorinated organic pollutants from water, achieving the following unexpected technical effects: (1) In this invention, methanogenic archaea are introduced. Methanosarcina barkeri By utilizing the reducing electrons and electron carriers generated during its metabolism, Fe(III) on the surface of sulfide nano-zero valent iron is reduced to Fe(II), thereby promoting the transformation and exfoliation of the passivation layer and restoring the active sites on the material surface. Compared with traditional nano-zero valent iron systems, this invention significantly improves material utilization and reduces the amount of material required to remove a unit of pollutant, demonstrating good economic efficiency.

[0018] (2) In this invention, sulfide nano-zero valent iron and Methanosarcina barkeri A synergistic mechanism is formed, in which the material provides electrons for the rapid reduction and degradation of pollutants, while the microorganisms promote the continuous supply and transfer of electrons through metabolic processes. The two complement each other, and this synergistic system significantly improves the removal rate and removal depth of chlorinated organic pollutants, showing obvious advantages compared with single material systems or single microbial systems.

[0019] (3) In this invention, through the participation of microorganisms, a stable electron transport channel is formed in the system, which promotes the efficient transfer of electrons between nano-zero valent iron and pollutants, while reducing the loss of electrons in side reactions (such as reactions with water or dissolved oxygen). This process effectively improves electron utilization efficiency, enabling more electrons to participate in the reduction reaction of the target pollutants, thereby improving the overall reaction efficiency.

[0020] (4) In this invention, the microbial-nanomaterial synergistic system can operate stably in an anaerobic groundwater environment without the need for complex external conditions. It has the advantages of high degradation efficiency, high material utilization rate and environmental friendliness. It is suitable for actual groundwater in-situ remediation projects and has good application prospects. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0022] Figure 1 This is a graph showing the change in the removal efficiency of p-chlorophenol over time in different reaction systems in Example 1 of the present invention.

[0023] Figure 2 These are SEM images of the sulfide nano-zero-valent iron in the reaction system before and after the reaction in Example 1 of this invention. They are used to characterize the changes in particle size and surface structure of the material.

[0024] Figure 3 These are TEM images of the sulfide nano-zero-valent iron in the reaction system of Example 1 of this invention before and after the reaction. They are used to characterize the changes in particle size and internal structure of the material.

[0025] Figure 4 The X-ray photoelectron spectra are shown in Example 1 of the present invention, which depict the changes in the valence state of iron on the surface of sulfide nano-zero valence iron before and after the reaction in different reaction systems. Figure 3 Used for analyzing Fe 0 The relative content changes of Fe(II) and Fe(III).

[0026] Figure 5 The graph shows the changes in the concentrations of free ferrous and ferric ions over time in different reaction systems in Example 1 of this invention.

[0027] Figure 6 The graph shows the electrochemical performance test results of different reaction systems in Example 1 of this invention. Figure 5 The data includes cyclic voltammetry (CV) curves and differential pulse voltammetry (DPV) curves, which are used to characterize the electron transport capability of the system.

[0028] Figure 7 This is a graph showing the change of headspace gases (H2, CH4, CO2) in different reaction systems with reaction time in Example 1 of the present invention.

[0029] Figure 8 This is a graph showing the degradation effect of the delayed inoculation experiment in Example 1 of the present invention. Figure 7 This was used to demonstrate the activation effect of microorganisms on inactivated S-NZVI. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0031] In the following embodiments of the present invention, unless otherwise specified, the materials and instruments used are commercially available, the equipment used is conventional equipment, and the data obtained are the average values ​​of more than three repeated experiments.

[0032] Example 1 A method for removing chlorinated organic pollutants from water using a coupling system of sulfide nano-zero-valent iron and methanogenic archaea involves adding sulfide nano-zero-valent iron and methanogenic archaea to the water containing chlorinated organic pollutants. ， A microbial-material coupled reaction system was constructed to degrade chlorinated organic pollutants in water. This embodiment provides a method for degrading p-chlorophenol in groundwater using *Pasteurella multocida* in synergistic effect with sulfidated nano-zero-valent iron, comprising the following steps: (1) Culture of Pasteurella multocida Pasteurella multocida ( Methanosarcina barkeri The DSM 800 medium was purchased from the German Microbiological and Cell Collection Center (DSMZ). Cultures were performed using DSMZ Medium 120. 50 mL of medium was transferred to 100 mL serum bottles, with a headspace volume of 50 mL. The headspace was purged with an 80% / 20% N2 / CO2 mixture until a final pressure of 100 kPa was reached. All media were autoclaved at 121°C for 30 min. The incubation temperature was 37°C.

[0033] (2) Preparation of sulfide nano-zero valent iron Sulfide nano-zero valent iron (S-NZVI) was prepared by a one-step liquid-phase reduction method, wherein the molar ratio of sulfur to iron was 1:30. The specific steps are as follows: Na2S2O3·5H2O and NaBH4 were mixed to prepare a 300 mL mixed solution with a NaBH4 concentration of 0.2 M. Under a nitrogen atmosphere, the mixed solution was added dropwise to a 300 mL 0.05 M FeCl3·6H2O solution (ferric chloride solution) with continuous stirring (250 rpm) at a dropping rate of approximately 7.5 mL / min. After the addition was completed, stirring was continued for 30 min. The synthesized S-NZVI particles were washed three times with anhydrous ethanol and dried in a vacuum drying oven at 60 °C for 15 h.

[0034] (3) Degradation experiment of p-chlorophenol Batch degradation experiments of p-chlorophenol (initial concentration 10 mg / L) were conducted in serum bottles, each containing 50 mL of DSMZ medium 120 and 50 mL of headspace volume. The serum bottles were purged with a N2 / CO2 mixture (80% / 20%) to remove oxygen, sealed with butyl rubber stoppers, and autoclaved at 121 °C for 30 min.

[0035] The following three processing systems are set up: System 1 ( M. barkeri ): Inoculate only with Pasteurella multocida (10%, v / v) System 2 (S-NZVI): Only S-NZVI (1 g / L) was added. System 3 (S-NZVI- M. barkeri ): Simultaneously add S-NZVI (1g / L) and Pasteurella multocida (10%, v / v) A blank control group (without any added materials or bacterial culture, Control) was also set up. Each treatment was performed in triplicate. All serum bottles were placed on a rotary shaker (150 rpm) and incubated at 37 ± 1 °C in the dark. Samples were taken for analysis on days 1, 3, 5, 10, and 15.

[0036] (4) Analytical methods The concentration of p-chlorophenol was determined by high-performance liquid chromatography (HPLC). The contents of H2, CH4, and CO2 in the headspace gas were determined by gas chromatography (GC).

[0037] (5) Results Figure 1 This is a graph showing the change in the removal efficiency of p-chlorophenol over time in different reaction systems in Example 1 of the present invention.

[0038] like Figure 1 As shown, almost no chlorophenol was removed in the blank control group (Control). The S-NZVI system alone (S-NZVI) rapidly degraded within the first 5 days (removal rate 44.2%), but the removal efficiency subsequently decreased to 38.3% by day 15, indicating rapid deactivation of the material due to surface passivation. The M. barkeri system alone ( M. barkeri The microorganism exhibited slow but continuous degradation, rising from 9.6% on day 5 to 34.5% on day 15, reflecting typical characteristics of the microbial adaptation period.

[0039] Completely different from them is the S-NZVI-M. barkeri synergistic system (S-NZVI- M. barkeri This system exhibited the most effective and sustained removal of p-chlorophenol. It degraded rapidly from the outset with no significant adaptation period, achieving a final removal rate of 85.5% after 15 days, significantly higher than the sum of the removal rates of the two individual systems. This indicates a clear synergistic effect rather than a simple additive effect. Morphological analysis of the materials before and after the reaction. The morphological changes of the S-NZVI material before and after the reaction were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Figure 2 , 3 ).

[0040] Figure 2 The images shown are SEM images of the sulfide nano-zero-valent iron in the reaction system before and after the reaction in Example 1 of this invention. Figure 2 In the image, a is the SEM image of the S-NZVI single system before the reaction of the sulfided nano-zero valent iron, b is the SEM image of the S-NZVI single system after the reaction of the sulfided nano-zero valent iron, and c is the SEM image of the S-NZVI-M. barkeri synergistic system after the reaction of the sulfided nano-zero valent iron.

[0041] Figure 3 The images shown are SEM and TEM images of the sulfide nano-zero valent iron in the reaction system before and after the reaction in Example 1 of this invention. Figure 3 In the image, a is a TEM image of the S-NZVI single system before the reaction of the sulfided nano-zero valent iron, b is a TEM image of the S-NZVI single system after the reaction of the sulfided nano-zero valent iron, and c is a TEM image of the S-NZVI-M. barkeri synergistic system after the reaction of the sulfided nano-zero valent iron.

[0042] Depend on Figure 2 , 3 It can be seen that before the reaction ( Figure 2 a, Figure 3 a) S-NZVI particles are spherical and exhibit a certain degree of aggregation. After the S-NZVI system reacts alone ( Figure 2 b、 Figure 3 (b) The particles transform into an aggregated, blocky structure, with a flocculent layer observed on the surface, corresponding to the Fe(III)(hydrogen) oxides formed during corrosion. After the synergistic reaction ( Figure 2 c. Figure 3 c) Although S-NZVI still aggregates, the particle size is significantly smaller than that of the standalone system, and the original spherical morphology is lost. This indicates that more S-NZVI is consumed in the coupled system, and the zero-valent iron core is more fully utilized.

[0043] Analysis of different iron speciation. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface chemical state before and after the S-NZVI reaction. Figure 4 ).

[0044] Figure 4 The X-ray photoelectron spectra are shown in Example 1 of the present invention, which depict the changes in the valence state of iron on the surface of sulfide nano-zero valence iron before and after the reaction in different reaction systems.

[0045] Depend on Figure 4It can be seen that before the reaction, the S-NZVI surface is dominated by Fe(0) and Fe(II). After the reaction, the S-NZVI system alone is dominated by Fe(III) (56.3%), while Fe(II) accounts for 32.7%. The high Fe(III) / Fe(II) ratio indicates the formation of a severe surface passivation layer. In contrast, in the synergistic system, Fe(II) increases to 46.33%, while Fe(III) decreases to 34.92%, and the Fe(III) / Fe(II) ratio is reversed.

[0046] Meanwhile, the contents of free ferrous and ferric iron in the reaction system were determined using the o-phenanthroline method. Figure 5 ).

[0047] Figure 5 The graph shows the changes in the concentrations of free ferrous and ferric ions over time in different reaction systems in Example 1 of this invention.

[0048] Depend on Figure 5 It can be seen that the concentration of free ferrous ions in the synergistic system is significantly higher than that in the S-NZVI system alone, while the concentration of ferric ions is low in all systems and there is no significant difference between the different systems. These results indicate that... M. barkeri The addition of [a substance] can increase the content of ferrous iron in the system and improve the system's reducing power.

[0049] Electrochemical analysis. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to analyze S-NZVI in the presence or absence of... M. barkeri Electron transfer behavior in the presence of ( Figure 6 ).

[0050] Figure 6 The graph shows the electrochemical performance test results of different reaction systems in Example 1 of this invention. Figure 6 In the figure, a is the CV curve and b is the DPV curve.

[0051] Depend on Figure 6 It can be seen that in a collaborative system, the CV curve ( Figure 6 a) and DPV curve ( Figure 6 b) The peak current was significantly enhanced and the area enclosed by the CV curve was significantly increased, indicating that *Paecilomyces pasteurellii* enhanced the electron transport kinetics and electron storage / transfer capacity of S-NZVI.

[0052] Headspace gas analysis Monitoring the changes in headspace gases (H2, CH4, CO2) in different systems with reaction time ( Figure 7 ).

[0053] Figure 7 This is a graph showing the change of headspace gases (H2, CH4, CO2) in different reaction systems with reaction time in Example 1 of the present invention. Figure 7 In the diagram, a represents the S-NZVI standalone system, and b represents... M. barkeri Individual system, c is the S-NZVI-M. barkeri synergistic system.

[0054] In the S-NZVI standalone system ( Figure 7 In (a), CH4 was not detected, CO2 concentration remained relatively constant, and H2 concentration initially increased rapidly before stabilizing. M. barkeri Individual system ( Figure 7 In b), H2 was not detected, and CH4 production exhibited a typical microbial growth curve. In the synergistic system ( Figure 7 In c), the H2 concentration decreased from day 1, falling below the detection limit by day 5, indicating that... M. barkeri The H2 produced by S-NZVI corrosion was rapidly consumed. Meanwhile, CH4 production plateaued from day 1 to day 5, with a slight decrease around day 3, corresponding to a sudden increase in CO2, indicating that an iron-dependent anaerobic methane oxidation (Fe-AOM) process occurred, proving the occurrence of the Fe(III) reduction process.

[0055] Delayed vaccination experiment To further confirm the reactivation effect of *Pasteurella multocida* on inactivated S-NZVI, a delayed inoculation experiment was designed. Figure 8 ).

[0056] Except for the microbial inoculation time, all other conditions were the same as in Example 1, specifically: First, allow S-NZVI to undergo a non-biological reaction with p-chlorophenol for 5 days. After the activity of S-NZVI decreases, inoculation is performed on day 5. M. barkeri The pollutant concentration will be restored to the initial concentration (10 mg / L).

[0057] Figure 8 This is a graph showing the degradation effect of the delayed inoculation experiment in Example 1 of the present invention.

[0058] Depend on Figure 8 It was observed that the pollutant concentration decreased rapidly after inoculation with microorganisms, then briefly rebounded, and subsequently decreased continuously. The re-degradation efficiency of pollutants after the addition of microorganisms reached 61%, which was significantly better than the degradation efficiency of microorganisms alone, demonstrating the reactivation effect of microorganisms on passivated S-NZVI.

[0059] The results above indicate that the microbial-material coupling reaction system (S-NZVI-) constructed using sulfide nano-zero-valent iron and methanogenic archaea in this invention is effective. M. barkeri In the synergistic system for degrading p-chlorophenol, S-NZVI provides rapid initial removal of p-chlorophenol through its strong reducing ability, while simultaneously generating H2 through anaerobic corrosion; on the other hand...M. barkeri It can not only biodegrade p-chlorophenol, but also utilize H2 for hydrogen-trophic methanogenesis. Simultaneously, it reduces Fe(III) through an iron-dependent anaerobic methane oxidation process, converting the Fe(III) passivation layer on the S-NZVI surface into Fe(II), thereby regenerating Fe. 0 / Fe 2+ Active site. Simultaneously M. barkeri Furthermore, its low redox potential electron carrier enhances the system's electron transport capacity. This closed-loop biogeochemical cycle mechanism of "microorganism-material synergy" achieves efficient degradation of p-chlorophenol and maintenance of the material's long-term reactivity. This invention boasts advantages such as high degradation efficiency, high material utilization, and environmental friendliness, making it suitable for practical in-situ groundwater remediation projects and demonstrating promising application prospects.

[0060] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for removing chlorinated organic pollutants from water using a coupling system of sulfide nano-zero-valent iron and methanogenic archaea, characterized in that, The method involves adding nano-zero-valent iron sulfide and methanogenic archaea to water containing chlorinated organic pollutants. ， A microbial-material coupled reaction system was constructed to degrade chlorinated organic pollutants in water.

2. The method according to claim 1, characterized in that, The amount of sulfide nano-zero valent iron added in the microbial-material coupling reaction system is 0.1 g / L to 2.0 g / L.

3. The method according to claim 2, characterized in that, The amount of sulfide nano-zero valent iron added in the microbial-material coupling reaction system is 0.5 g / L to 1.5 g / L.

4. The method according to claim 3, characterized in that, The molar ratio of sulfur to iron in the sulfide nano-zero valent iron is 1:30; the sulfide nano-zero valent iron is prepared by reducing iron salt and thiosulfate with sodium borohydride; the preparation method of the sulfide nano-zero valent iron includes the following steps: mixing thiosulfate and sodium borohydride to prepare a mixed solution, adding the mixed solution dropwise to an iron salt solution under a nitrogen atmosphere and stirring to carry out a reduction reaction, continuing stirring after the addition is completed, magnetic separation, washing, and drying to obtain sulfide nano-zero valent iron.

5. The method according to claim 4, characterized in that, The thiosulfate is Na₂S₂O₃·5H₂O; the concentration of sodium borohydride in the mixed solution is 0.2M; the dropping rate of the mixed solution is 7.5 mL / min; the iron salt solution is ferric chloride solution; The concentration of the iron salt solution is 0.05M; the washing is performed by washing 2 to 3 times with anhydrous ethanol; the drying is performed by drying under vacuum at 60°C for 15 hours.

6. The method according to any one of claims 1 to 5, characterized in that, The inoculation amount of methanogenic archaea in the microbial-material coupling reaction system is 2% to 20% (v / v).

7. The method according to claim 6, characterized in that, The inoculation amount of methanogenic archaea in the microbial-material coupling reaction system is 5% to 15% (v / v).

8. The method according to claim 7, characterized in that, The methanogenic archaea mentioned is *Pasteurella multocida*, and its name is... Methanosarcina barkeri DSM 800.

9. The method according to any one of claims 1 to 5, characterized in that, The chlorinated organic pollutant water body is groundwater containing chlorinated organic pollutants; the initial concentration of chlorinated organic pollutants in the chlorinated organic pollutant water body is ≤10mg / L; the chlorinated organic pollutant is p-chlorophenol.

10. The method according to any one of claims 1 to 5, characterized in that, The degradation process was carried out under anaerobic conditions; the degradation process was carried out at a temperature of 37±1℃ and a rotation speed of 150rpm; the degradation process lasted for 15 days.

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