Preparation method and application of semiconductor mineral composite functional biomaterials for promoting reductive dechlorination
By preparing a composite material of semiconductor minerals and dechlorinating respiratory bacteria, and utilizing it as a natural 'electron conduit', the problem of long remediation time and unstable effect of 2,4,6-TCP contamination in microbial remediation technology was solved, achieving rapid and stable dechlorination effect and efficient microbial remediation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HARBIN INST OF TECH
- Filing Date
- 2023-04-12
- Publication Date
- 2026-04-28
AI Technical Summary
Existing microbial remediation technologies for soil and groundwater contamination with chlorophenols (CPs) are time-consuming and have unstable effects, making it difficult to achieve a rapid and effective dechlorination process.
A composite functional biomaterial that promotes microbial reductive dechlorination was prepared by combining semiconductor minerals with dechlorinating respiratory bacteria. The semiconductor minerals act as natural 'electron conduits' and work together with microorganisms to promote the reductive dechlorination process of 2,4,6-trichlorophenol (2,4,6-TCP).
It achieves rapid and stable 2,4,6-TCP dechlorination, improves the reduction rate of halogenated organic pollutants by microorganisms, enhances the remediation effect of microbial remediation technology, and the material is natural and has no secondary pollution.
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Figure CN116515493B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing and applying a semiconductor mineral composite functional biomaterial that promotes reduction and dechlorination, belonging to the field of environmental bioremediation technology. Background Technology
[0002] With the acceleration of industrialization and urbanization, the pollution problem of chlorinated organic compounds in soil and groundwater in my country has become increasingly serious. Chlorophenols (CPs) are widely used as organic intermediates in the production of pesticides, dyes, and preservatives. However, CPs are difficult to degrade in the environment, exhibiting environmental persistence, and have teratogenic, carcinogenic, and mutagenic effects on organisms, thus being recognized as toxic and hazardous pollutants. Currently, many CPs are listed as priority pollutants for groundwater environmental control and substances subject to risk management for soil environmental quality.
[0003] For contaminants (CPs) in soil and groundwater, microbial remediation offers advantages such as low cost, simple operation, and good results. However, existing microbial remediation technologies for CPs pollution suffer from drawbacks such as long remediation times and unstable remediation effects. Therefore, it is essential to provide a composite material that promotes stable and rapid dechlorination by microorganisms and its preparation method, representing a new trend in achieving in-situ remediation of contaminated soil and groundwater sites. Summary of the Invention
[0004] 2,4,6-Trichlorophenol (2,4,6-TCP) is a typical CP (concentrated phenol). This invention addresses the problem of 2,4,6-TCP contamination in existing soil and groundwater sites by proposing an eco-friendly composite functional biomaterial that promotes the reduction and dechlorination of 2,4,6-TCP using semiconductor minerals, and provides a detailed preparation method for this biomaterial.
[0005] The technical solution of the present invention:
[0006] The purpose of this invention is to provide a composite functional biomaterial in which semiconductor minerals promote the reductive dechlorination of 2,4,6-TCP. The method includes the following steps:
[0007] S1. Grind hematite or rutile, sieve to obtain mixed powder, mix the mixed powder with distilled water, sonicate, centrifuge, discard the supernatant, dry the remaining part, wash the dried remaining part in anhydrous ethanol, centrifuge and dry the precipitate to obtain semiconductor mineral powder, and seal and store.
[0008] S2, inorganic culture medium solution and semiconductor mineral powder are added to an anaerobic tank, aerated and sterilized, and then the target chlorinated organic compound 2,4,6-TCP is added. Then, 2,4,6-TCP dechlorination and respiration bacteria are inoculated and cultured at a constant temperature of 30℃. During the culture period, the culture medium is changed regularly and the target chlorinated organic compound is added. The culture is continued for 18 to 22 days, and centrifuged to obtain a composite material that promotes microbial dechlorination.
[0009] Further specified, the particle size of mineral powder in S1 is ≤200 mesh.
[0010] Further specifying, the target chlorinated organic compound in S2 is 2,4,6-TCP.
[0011] Further specifying, the concentration of semiconductor mineral powder added to the inorganic culture medium solution in S2 is 1 g / L.
[0012] Further specifying, the final concentration of the target halogenated organic compound added to S2 is 100 μmol / L.
[0013] Further specifying, the inorganic culture medium solution is a liquid culture medium prepared with deionized water, comprising: 1 g / L NaCl, 0.2 g / L MgCl2·6H2O, 2.31 g / L Na2HPO4·12H2O, 0.554 g / L NaH2PO4·2H2O, 0.13 g / L NH4Cl, 0.3 g / L KCl, 0.012 g / L CaCl2, 0.1 mL / L mineral element 1, and 0.1 mL / L mineral element 2.
[0014] Furthermore, the basic solution formula for mineral element 1 is as follows: 0.5 mg / L LnCl2·4H2O, 0.5 mg / L ZnCl2, 0.5 mg / L NiCl2·6H2O, 0.5 mg / L H3BO3, 0.5 mg / L Na2MoO4·2H2O, and 2.5 mg / L CoCl2·6H2O.
[0015] Furthermore, the basic solution formulation for mineral element 2 is: 0.5 mg / L NH4VO3, 2.5 mg / L KI, and 10 mg / L (NaPO3). 16 .
[0016] Further specified, the inoculation volume of the 2,4,6-TCP dechlorination respiratory bacteria in S2 is 5% of the volume of the inorganic culture medium solution.
[0017] Further specifying, the 2,4,6-TCP dechlorination respiration bacterial culture in S2 is a domesticated anaerobic mixed bacterial community, and the domestication process is as follows:
[0018] (1) Take soil from the 2,4,6-TCP contaminated area and add it to an anaerobic bottle. Add inorganic salt culture medium to the anaerobic bottle, blow it off with nitrogen, and then seal it.
[0019] (2) Inject 2,4,6-TCP concentrate into the sealed anaerobic bottle, shake well, and place in a 30℃ constant temperature incubator. Take samples daily and test the TCP concentration. After the TCP concentration drops to 0, add the same amount of 2,4,6-TCP concentrate as the first time and repeat the above steps. Cultivate for 3 months to obtain the TCP dechlorination and respiration bacterial solution. The obtained TCP dechlorination and respiration bacterial solution shows a stable dechlorination state of TCP with a dechlorination cycle of 8 days.
[0020] Further specifying, the 2,4,6-TCP concentrate in S2 is 100X, with a final concentration of 100 μmol / L.
[0021] This invention utilizes the fact that the combination of semiconductor minerals and dechlorination-respirating bacteria such as Pseudomonas can promote the growth and metabolism of microorganisms, ultimately facilitating the dechlorination process of 2,4,6-TCP. Furthermore, this invention has the following advantages compared to existing technologies:
[0022] (1) This invention uses semiconductor minerals as natural “electron conduits” to prepare composite materials that promote microbial reduction and dechlorination. After preparing semiconductor mineral materials using a simple grinding method, they can be directly added to 2,4,6-TCP dechlorination bacterial solution, so that functional bacteria such as Pseudomonas aeruginosa CP-1 can be loaded onto the mineral particles. The resulting composite material has a good dechlorination effect on 2,4,6-TCP. Moreover, all the materials used are natural materials, which will not cause secondary pollution to the environment and have extremely high environmental friendliness.
[0023] (2) The semiconductor minerals used in this invention are micron-sized and have good dispersibility and stability, allowing for sufficient contact with microorganisms. They not only do not have a toxic effect on dechlorination-respiratory bacteria, but also promote the growth and metabolism of related microorganisms. Furthermore, the selected semiconductor minerals are all natural minerals, abundant in nature, and low in cost. As natural "electron conduits" between microorganisms or between microorganisms and other non-living electron donors and acceptors, they can promote rapid electron transfer between species, providing an additional electron source for the dechlorination-respiratory strain Pseudomonas aeruginosa CP-1. In addition, semiconductor mineral materials can modify community structure, promote the abundance of dechlorination-related strains, provide more adsorption sites for pollutants and microorganisms, and effectively improve the reduction rate of halogenated organic pollutants by anaerobic microorganisms.
[0024] (3) The semiconductor mineral / microbial composite material prepared by the present invention is an important development direction for enhanced microbial remediation technology. It is easier to apply to actual engineering remediation and realize in-situ remediation of chlorinated organic pollution in soil and groundwater sites. Attached Figure Description
[0025] Figure 1 The graph shows the change in 2,4,6-TCP concentration during the biological dechlorination process of the iron oxide (Fe2O3) semiconductor mineral prepared in Example 1.
[0026] Figure 2 The graph shows the concentration change of 2,4,6-TCP during the biological dechlorination process of the titanium dioxide (TiO2) semiconductor mineral prepared in Example 2.
[0027] Figure 3 The graph shows the concentration changes of 2,4,6-TCP in the pyrite (FeS) semiconductor mineral prepared for Comparative Example 1 during biological dechlorination. Detailed Implementation
[0028] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.
[0029] Example 1:
[0030] This embodiment uses hematite (iron oxide, Fe2O3) as a semiconductor mineral to prepare a composite material that promotes microbial dechlorination. The specific preparation method is as follows:
[0031] (1) Weigh 10g of natural hematite (Fe2O3) particles, grind them thoroughly in a grinder, and then sieve them with a 200-mesh sieve to obtain semiconductor mineral materials with a diameter ≤200 mesh.
[0032] (2) The sieved semiconductor mineral material was placed in 50 mL of pure water and sonicated for 15 min to remove some inorganic impurities. Then, it was centrifuged at 1000 r / min, the supernatant was discarded, and the remaining portion was dried in a 65℃ oven for 2 h. Using the same procedure, the dried semiconductor mineral was washed in anhydrous ethanol to remove any organic impurities that might adhere to the mineral surface. After centrifugation, the precipitate was dried in a 65℃ oven for 2 h. The resulting semiconductor mineral powder was stored at room temperature. The semiconductor mineral powder prepared from hematite mainly consists of α-Fe2O3, exhibiting hematite crystal form. The semiconductor mineral powder is mostly spherical with a diameter of approximately 2-4 micrometers.
[0033] (3) Prepare liquid anaerobic culture medium with deionized water according to the following formula: 1 g / L NaCl, 0.2 g / L MgCl2·6H2O, 2.31 g / L Na2HPO4·12H2O, 0.554 g / L NaH2PO4·2H2O, 0.13 g / L NH4Cl, 0.3 g / L KCl, 0.012 g / L CaCl2, 0.1 mL / L mineral element 1 and 0.1 mL / L mineral element 2. The basic solution formulation for mineral element 1 is as follows: 0.5 mg / L LnCl₂·4H₂O, 0.5 mg / L ZnCl₂, 0.5 mg / L NiCl₂·6H₂O, 0.5 mg / L H₃BO₃, 0.5 mg / L Na₂MoO₄·2H₂O, 2.5 mg / L LcoCl₂·6H₂O; the basic solution formulation for mineral element 2 is as follows: 0.5 mg / L NH₄VO₃, 2.5 mg / L KI, 10 mg / L (NaPO₃). 16 Pour 1.2L of prepared anaerobic culture medium into a 2L serum bottle, add 2g of semiconductor mineral powder, and deoxygenate by purging with high-purity nitrogen for 20 minutes. Seal the container. Then autoclave at 121℃ to obtain a sterile initial solution.
[0034] (4) Then inject a final concentration of 2 mmol / L Na2S solution, 3 ml of 2 mol / L sodium acetate solution, 1.2 ml of vitamins, and a final concentration of 100 μmol / L 2,4,6-TCP solution into the sterile initial solution. Then inoculate the dechlorinated respiratory bacteria solution with a volume of 5% of the volume of the sterile initial culture medium.
[0035] Among them, the dechlorination-respirating bacterial solution is a domesticated anaerobic mixed bacterial group, and the domestication process is as follows:
[0036] ① Take 100g of soil from an area contaminated with 2,4,6-TCP, divide it into ten equal portions, and place them into 100ml anaerobic bottles. Then, add 60ml of inorganic salt culture medium to each anaerobic bottle, purge with high-purity nitrogen gas for 20 minutes, and seal with rubber stoppers.
[0037] ② Add 0.06 mL of 100X concentrated 2,4,6-TCP solution to each anaerobic bottle using a microsyringe to achieve a final concentration of 100 μmol / L. Shake well and incubate at 30℃. Take samples daily and monitor the 2,4,6-TCP concentration. Once the 2,4,6-TCP concentration drops to 0, add the same amount of concentrated 2,4,6-TCP solution as the first time and repeat the above steps. Incubate for 3 months to obtain the 2,4,6-TCP dechlorination and respiration bacterial culture. The obtained 2,4,6-TCP dechlorination and respiration bacterial culture exhibits a stable dechlorination state of 2,4,6-TCP, with the final product being 4-CP. The dechlorination cycle for 100 μM 2,4,6-TCP is approximately 8 days.
[0038] (5) Cultivate at a constant temperature of 30℃, detect the concentration of 2,4,6-TCP in the anaerobic tank daily, and replenish the target pollutant in a timely manner for two weeks to ensure that the mineral material and microorganisms are in full contact and play the role of natural "electron conduit". Finally, centrifuge the liquid-solid mixture in the anaerobic tank and the precipitate obtained is the composite material that promotes microbial dechlorination.
[0039] Control group: Take one serum bottle and prepare the same liquid culture medium according to the above ingredients. Pour 1.2L of the prepared anaerobic culture medium into a 2L serum bottle without adding any semiconductor mineral materials. After purging with nitrogen, seal the anaerobic bottle. Autoclave at 121℃ to obtain a sterile initial solution. Sequentially inject the following into the anaerobic culture bottle: a final concentration of 2mmol / L Na2S solution, 3ml of a 2mol / L sodium acetate solution, 1.2ml of vitamins, a final concentration of 100μmol / L 2,4,6-TCP solution, and an inoculation volume of 5% of the sterile initial culture medium volume of dechlorinated respiratory bacteria. This group serves as the control group.
[0040] The concentrations of target pollutants 2,4,6-TCP and dechlorination products were periodically measured in Example 1 and the control group. The periodic test results of the target pollutants are as follows: Figure 1 As shown, in Example 1, the concentration of 2,4,6-TCP decreased to 0 within 4 days, while the concentration of 4-CP reached its highest value. The TCP degradation kinetics k-value in the culture medium was the highest, which was 2.6 times that of the control group.
[0041] Furthermore, the relative abundance of the 2,4,6-TCP dechlorination-associated strain Desulfitobacterium hafniense Y51 in the container of Example 1 increased from 1.93% to 14.96% compared to the control group.
[0042] In summary, iron oxide semiconductor mineral materials can act as natural "electron conduits" to promote the growth and metabolism of dechlorination-respiring microorganisms, thereby enhancing the biological dechlorination reaction. Furthermore, the materials can increase the relative abundance of dechlorination-respiring strains, alter community structure, and improve the dechlorination efficiency of chlorinated pollutants.
[0043] Example 2:
[0044] This embodiment uses titanium dioxide (TiO2) as a semiconductor mineral to prepare a composite material that promotes microbial dechlorination. The specific preparation method is as follows:
[0045] (1) Take 10g of natural TiO2 particles, put them into a grinder for thorough grinding, and then sieve them with a 200-mesh sieve to obtain semiconductor mineral materials with a diameter ≤200 mesh.
[0046] (2) The sieved semiconductor mineral material was placed in 50 mL of pure water and sonicated for 15 min to remove some inorganic impurities. Then, it was centrifuged at 1000 r / min, the supernatant was discarded, and the remaining portion was dried in a 65℃ oven for 2 h. Using the same procedure, the dried semiconductor mineral was washed in anhydrous ethanol to remove any organic impurities that might adhere to the mineral surface. After centrifugation, the precipitate was dried in a 65℃ oven for 2 h. The dried semiconductor mineral powder was stored at room temperature. The semiconductor mineral material prepared from titanium dioxide was a mixture of rutile and anatase in approximately a 3:1 ratio. Both crystal forms of titanium dioxide exhibited electrical conductivity. The titanium dioxide semiconductor mineral powder was mostly spherical with a diameter of approximately 2-4 micrometers.
[0047] (3) Prepare liquid anaerobic culture medium with deionized water according to the following formula: 1 g / L NaCl, 0.2 g / L MgCl2·6H2O, 2.31 g / L Na2HPO4·12H2O, 0.554 g / L NaH2PO4·2H2O, 0.13 g / L NH4Cl, 0.3 g / L KCl, 0.012 g / L CaCl2, 0.1 mL / L mineral element 1 and 0.1 mL / L mineral element 2. The basic solution formulation for mineral element 1 is as follows: 0.5 mg / L LnCl₂·4H₂O, 0.5 mg / L ZnCl₂, 0.5 mg / L NiCl₂·6H₂O, 0.5 mg / L H₃BO₃, 0.5 mg / L Na₂MoO₄·2H₂O, 2.5 mg / L LcoCl₂·6H₂O; the basic solution formulation for mineral element 2 is as follows: 0.5 mg / L NH₄VO₃, 2.5 mg / L KI, 10 mg / L (NaPO₃). 16 Pour 1.2L of prepared anaerobic culture medium into a 2L serum bottle, add 2g of semiconductor mineral powder, and deoxygenate by purging with high-purity nitrogen for 20 minutes. Seal the container. Then autoclave at 121℃ to obtain a sterile initial solution.
[0048] (4) Then inject a final concentration of 2 mmol / L Na2S solution, 3 ml of 2 mol / L sodium acetate solution, 1.2 ml of vitamins, and a final concentration of 100 μmol / L 2,4,6-TCP solution into the sterile initial solution. Then inoculate the dechlorinated respiratory bacteria solution with a volume of 5% of the volume of the sterile initial culture medium.
[0049] Among them, the dechlorination-respirating bacterial solution is a domesticated anaerobic mixed bacterial group, and the domestication process is as follows:
[0050] ① Take 100g of soil from an area contaminated with 2,4,6-TCP, divide it into ten equal portions, and place them into 100ml anaerobic bottles. Then, add 60ml of inorganic salt culture medium to each anaerobic bottle, purge with high-purity nitrogen gas for 20 minutes, and seal with rubber stoppers.
[0051] ② Add 0.06 mL of 100X concentrated 2,4,6-TCP solution to each anaerobic bottle using a microsyringe to achieve a final concentration of 100 μmol / L. Shake well and incubate at 30℃. Take samples daily and monitor the 2,4,6-TCP concentration. Once the 2,4,6-TCP concentration drops to 0, add the same amount of concentrated 2,4,6-TCP solution as the first time and repeat the above steps. Incubate for 3 months to obtain the TCP dechlorination and respiration bacterial culture. The obtained TCP dechlorination and respiration bacterial culture exhibits a stable dechlorination state for 2,4,6-TCP, with the final product being 4-CP. The dechlorination cycle for 100 μM 2,4,6-TCP is approximately 8 days.
[0052] (5) Cultivate at a constant temperature of 30℃, detect the concentration of 2,4,6-TCP in the anaerobic tank daily, and replenish the target pollutant halogenated organic pollutant in a timely manner for two weeks to ensure that the mineral material and microorganisms are in full contact and play the role of natural "electron conduit". Finally, centrifuge the liquid-solid mixture in the anaerobic tank and the precipitate obtained is the composite material that promotes microbial dechlorination.
[0053] The concentrations of target pollutants 2,4,6-TCP and dechlorination products were periodically measured in Example 2 and the control group. The periodic test results of the target pollutants are as follows: Figure 2 As shown, in Example 2, the TCP concentration decreased to 0 within 6 days, the 4-CP concentration reached its highest value, and the TCP degradation kinetics k value in the culture medium was the highest, which was 2.6 times that of the control group.
[0054] Furthermore, in Example 2, the relative abundance of the TCP dechlorination functional strain Pseudomonasaeruginosa CP-1 in the container increased by 25.4% compared to the control group, and the abundance of the electron transport-related strain Azospiraoryzae increased by 24.30% compared to the control group.
[0055] In summary, titanium dioxide semiconductor mineral materials possess excellent electrical conductivity, serving as natural "electron conduits" to promote the growth and metabolism of dechlorination-functional strains. Furthermore, the material can increase the abundance of strains related to electron transport and dechlorination respiration, altering the community structure and ultimately achieving highly efficient dechlorination of chlorinated pollutants.
[0056] As can be seen from Examples 1 and 2, semiconductor mineral materials prepared from iron oxide or titanium oxide can be used as natural "electron conduit" functional materials to enhance the dechlorination reaction of dechlorinated respiratory bacteria on 2,4,6-TCP.
[0057] Specifically, a 2L system was used to simulate the steps of different semiconductor mineral materials production. The results showed that this method still has a good promoting effect in large-scale polluted water bodies. The semiconductor mineral material preparation method, dehalogenation respiratory bacteria loading method, and in-situ bioremediation method for halogenated organic pollution in groundwater provided by this invention all have significant advantages in large-scale applications and are worthy of further promotion.
[0058] Furthermore, the semiconductor mineral material loaded with dehalogenating respiratory bacteria can be applied to an in-situ enhanced biological dehalogenation method in soil. This method involves directly adding semiconductor minerals as a natural electron conduit to a composite material that mediates and promotes microbial dehalogenation in soil contaminated with halogenated organic matter, thereby enhancing the microbial remediation of the soil environment.
[0059] Comparative Example 1:
[0060] This comparative example uses pyrite (FeS) as the semiconductor mineral to prepare a composite material that promotes microbial dechlorination. The specific preparation method is the same as in Example 1.
[0061] The concentrations of target pollutant 2,4,6-TCP and dechlorination products were periodically measured in both the comparative and control groups. The periodic test results of the target pollutant are as follows: Figure 3 As shown in the figure, pyrite (FeS) as a semiconductor mineral does not promote the degradation of 2,4,6-TCP. This indicates that not all micron-sized semiconductor minerals have the effect of promoting the degradation of 2,4,6-TCP by the domesticated bacterial solution.
[0062] The above description is only a preferred embodiment of the present invention. Given that those skilled in the art can make appropriate changes and modifications to the above embodiments, the present invention is not limited to the specific embodiments described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention.
Claims
1. A method for preparing a semiconductor mineral composite functional biomaterial that promotes reductive dechlorination, characterized in that, include: S1. Grind iron oxide or titanium oxide, sieve to obtain mineral powder, mix mineral powder with distilled water, sonicate, centrifuge, discard supernatant, dry the remaining part, place the dried remaining part in anhydrous ethanol for washing, centrifuge and dry the precipitate to obtain semiconductor mineral powder, and seal and store. S2, Inorganic culture medium solution and semiconductor mineral powder are added to an anaerobic tank, aerated and sterilized, and then the target halogenated organic matter is added. Then, 2,4,6-TCP dechlorination and respiration bacteria are inoculated and cultured at a constant temperature of 30℃. During the culture period, the culture medium is changed regularly and the target halogenated organic matter is added. The culture is continued for 18-22 days, and centrifuged to obtain a composite material that promotes microbial dechlorination. The target halogenated organic compound in S2 is 2,4,6-TCP; The 2,4,6-TCP dechlorination respiration bacterial culture in S2 is a domesticated mixed anaerobic bacterial community. The domestication process is as follows: (1) Take soil from the area contaminated by 2,4,6-TCP and add it to an anaerobic bottle. Add inorganic salt culture medium to the anaerobic bottle, blow it off with nitrogen, and then seal it. (2) Inject 2,4,6-TCP concentrate into the sealed anaerobic bottle to make the final concentration 100 μmol / L, shake well, and place in a constant temperature incubator at 30℃. Take samples daily and test the TCP concentration. After the TCP concentration drops to 0, add the same amount of 2,4,6-TCP concentrate as the first time, repeat the above steps, and culture for 3 months to obtain the bacterial culture, which is the 2,4,6-TCP dechlorination and respiration bacterial culture.
2. The preparation method according to claim 1, characterized in that, In S1, the particle size of the mineral powder is ≤200 mesh.
3. The preparation method according to claim 1, characterized in that, The final concentration of the target pollutant 2,4,6-TCP added to S2 is 100 μmol / L.
4. The preparation method according to claim 1, characterized in that, The inoculation volume of the dechlorinated respiratory bacteria in S2 is 5% of the volume of the inorganic culture medium solution.
5. The preparation method according to claim 1, characterized in that, (2) The 2,4,6-TCP concentrate is 100X, and the final concentration is 100μmol / L.
6. A composite material for promoting microbial dechlorination obtained by the preparation method according to any one of claims 1 to 5.
7. The application of the composite material for promoting microbial dechlorination as described in claim 6, characterized in that, For in-situ enhanced biological dechlorination of 2,4,6-TCP contaminants in soil or groundwater.