A carbon-based microbial inoculant for synchronously degrading halogenated organic compounds and passivating heavy metals, and a preparation method and application thereof

Abstract

The application discloses a carbon-based microbial agent for synchronously degrading halogenated organic compounds and passivating heavy metals, and a preparation method and application thereof. The carbon-based microbial agent comprises composite microorganisms and biochar, the composite microorganisms comprise chitin bacteria, bacillus, achromobacter, methyl bacillus, sphingomonas and microbacterium, and the composite microorganisms are attached to the surface of the biochar. The preparation method of the carbon-based microbial agent is that six kinds of microbial strains are inoculated into culture media containing pollutants respectively, and after screening and domestication, the carbon-based microbial agent is obtained by incubating the six kinds of microbial strains with the biochar. The carbon-based microbial agent can synchronously degrade halogenated organic compounds and passivate heavy metals, the degradation rate of BDE-47 in actual electronic waste disassembly area composite contaminated soil can reach 89.60%, the degradation rate of PCB 180 can reach 94.99%, the passivation rates of lead and cadmium can reach 76.39% and 90.37% respectively, and the carbon-based microbial agent is suitable for heavy metal-organic compound composite contaminated site remediation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of environmental treatment, and particularly relates to a carbon-based microbial inoculum for simultaneously degrading halogenated organic compounds and passivating heavy metals, and a preparation method and application thereof. BACKGROUND

[0002] Electronic waste contains various pollutants, including halogenated organic pollutants such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), and various heavy metals such as cadmium (Cd), copper (Cu), and lead (Pb). These pollutants are difficult to biodegrade and remove, and are easily released to environmental media such as water, air, soil, and sediments, posing risks to ecological environment safety and human health. Moreover, halogenated toxic organic compounds and heavy metals coexist in the soil for a long time, and complex interactions between these pollutants greatly increase the difficulty of remediation of the compound contaminated soil. Therefore, how to safely and efficiently simultaneously degrade halogenated organic pollutants and passivate heavy metals is a technical problem that needs to be solved urgently.

[0003] The microbial method has the advantages of economy, greenness, and simplicity, and can be combined with other remediation technologies. However, in actual operation, it is not only susceptible to external environmental influences (such as temperature, moisture, and heavy metal toxicity), but also constrained by nutrient sources (carbon source, nitrogen source, phosphorus source, etc.), making it difficult to play a practical role in biodegradation and biopassivation. In particular, single microorganisms have poor environmental tolerance and are prone to competition with indigenous microorganisms, resulting in a long remediation period and seriously affecting the remediation efficiency. Microbial flora contains different functional strains and has a stable flora structure, and has stronger resistance when subjected to external environmental stress. In addition, the cooperation and synergy between different strains have good degradation and passivation capacity for toxic organic compounds and heavy metals.

[0004] Porous biochar is used as a microbial flora carrier, and the soluble organic matter in the biochar can provide external nutrients for the microbial flora. The unique pore structure of the biochar can serve as a shelter for the microorganisms. The alkaline property of the biochar can neutralize the organic acid in the soil to improve the soil environment. In addition, the biochar can stimulate the interaction between microbial strains, improve the tolerance of the microbial flora and the ability to degrade and remove pollutants, and reduce the half-life of the pollutants, and has broad application prospects. The currently reported biochar immobilized microorganisms are generally only used for remediation of single organic or heavy metal pollution, and there are few reports on the co-remediation of halogenated organic compounds and heavy metals.

[0005] Therefore, in order to overcome the environmental disturbance of the strains, a carbon-based bacterial inoculum with good tolerance and immobilization capacity for heavy metals and high degradation capacity for halogenated organic compounds is provided, and the simultaneous degradation of halogenated organic compounds and passivation of heavy metals in the contaminated soil medium becomes a technical problem that needs to be solved urgently in this technical field. SUMMARY

[0006] In order to overcome the problems existing in the prior art, the purpose of the present application is to provide a carbon-based microbial agent for synchronously degrading halogenated organic matter and passivating heavy metals, and a preparation method and application thereof.

[0007] The inventive concept of the present application is:

[0008] Compared with single functional strains, the complex microbial flora has stronger environmental adaptability, metabolic complementarity and mutual interaction. Different functional bacterial species in the complex microbial flora can cooperate with each other, share biochemical steps of each other, realize metabolic diversity, and thus have stronger tolerance, passivation, degradation and removal capabilities for the synergistic effect of heavy metals-organic matter.

[0009] In addition, compared with free microbial agents, the immobilized microbial agent has the advantages of high biomass, not easy to lose, and strong anti-toxicity. Biochar has a developed pore structure and a large specific surface area, which can provide a good habitat for the growth and reproduction of microorganisms. Biochar can fix heavy metals in the soil to a certain extent, reduce the toxicity stress of the microbial agent, and maintain the biodegradation activity. Moreover, biochar can further stimulate the intermediate interaction of different bacterial species in the complex microorganisms, so that the passivation and degradation capacity of the complex microbial agent for heavy metals-organic matter is further enhanced. Therefore, the present application designs a complex microbial agent composed of different functional bacterial species loaded on biochar as a carrier for synchronously degrading halogenated organic matter and passivating heavy metals, which is expected to become a green and efficient remediation technology. In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0010] In a first aspect, the present application provides a carbon-based microbial agent, wherein the complex microorganisms are attached to the surface of biochar; and the complex microorganisms include chitin bacteria, bacillus, achromobacter, methyl bacillus, sphingomonas and microbacterium.

[0011] Specifically, the microbial strains are respectively enriched and domesticated in a culture medium containing pollutants to obtain enriched and domesticated chitin bacteria, enriched and domesticated bacillus, enriched and domesticated achromobacter, enriched and domesticated methyl bacillus, enriched and domesticated sphingomonas and enriched and domesticated microbacterium.

[0012] Preferably, the complex microorganisms are composed of chitin bacteria MH-1, bacillus HY-1, achromobacter YH-1, methyl bacillus ZY-1, sphingomonas GY-1 and microbacterium, wherein the preservation number of the microbacterium is GDMCC No: 60634.

[0013] In the present application, the Chitinophaga sp. is Chitinophaga sp. MH-1, which is classified as Chitinophaga sp. and has a preservation number of GDMCC No: 62742 and a genebank accession number of OP703376.

[0014] The Bacillus sp. is Bacillus sp. HY-1, which is classified as Bacillus sp. and has a preservation number of GDMCC No: 62740 and a genebank accession number of OP703374.

[0015] The Achromobacter sp. is Achromobacter sp. YH-1, which is classified as Achromobacter sp. and has a preservation number of GDMCC No: 62741 and a genebank accession number of OP703375.

[0016] The Methylorubrum sp. is Methylorubrum sp. ZY-1, which is classified as Methylorubrum sp. and has a preservation number of GDMCC No: 62743 and a genebank accession number of OP703377.

[0017] The Sphingomonas sp. is Sphingomonas sp. GY-1, which has a preservation number of GDMCC No: 60633 and is disclosed in Chinese patent CN110257280A.

[0018] The Microbacterium sp. has a preservation number of GDMCC No: 60634 and is disclosed in Chinese patent CN110511881A.

[0019] The Chitinophaga sp. MH-1, the Bacillus sp. HY-1, the Achromobacter sp. YH-1, and the Methylorubrum sp. ZY-1 were preserved in the Guangdong Microbial Culture Collection Center on August 25, 2022. The above-mentioned strains can be purchased from the Guangdong Microbial Culture Collection Center. The address of the Guangdong Microbial Culture Collection Center is Building 59, No. 5, 100, Martyrs' Road, Guangzhou.

[0020] Preferably, the complex microorganism is screened and domesticated.

[0021] Preferably, the screening and domestication use a culture medium containing pollutants, and the pollutants include tetrabromobisphenol A, heptachlor biphenyl, and heavy metal cadmium.

[0022] Further preferably, the screening and acclimation use a culture medium containing pollutants including 0.5 mg / L to 15 mg / L 2,2',4,4'-tetrabromodiphenyl ether, 0.5 mg / L to 15 mg / L 2,2',3,4,4',5,5'-heptachlorobiphenyl, 0.5 mg / L to 15 mg / L heavy metal cadmium.

[0023] Further preferably, the culture medium containing pollutants includes 1 mg / L to 10 mg / L 2,2',4,4'-tetrabromodiphenyl ether, 1 mg / L to 10 mg / L 2,2',3,4,4',5,5'-heptachlorobiphenyl, 1 mg / L to 10 mg / L heavy metal cadmium.

[0024] Preferably, the culture medium containing pollutants is a liquid medium, which further includes 2.8 g / L to 3.2 g / L K2HPO4, 1.2 g / L to 1.8 g / L KH2PO4, 0.8 g / L to 1.2 g / L (NH4)2SO4, 0.4 g / L to 0.6 g / L NaCl, 2 mL / L trace element solution and distilled water.

[0025] Preferably, the trace element solution is mixed from the following components and distilled water: 3.8 g / L to 4.3 g / L MgSO4, 0.8 g / L to 1.2 g / L CuSO4, 0.8 g / L to 1.2 g / L MnSO4, 0.8 g / L to 1.2 g / L FeSO4·7H2O, 0.8 g / L to 1.2 g / L CaCl2.

[0026] Preferably, the number of viable bacteria of each microorganism in the carbon-based microbial agent is respectively: chitin bacteria 4.5 x 10 8 ~ 2.0 x 10 9 CFU / g, bacillus 2.0 x 10 8 ~ 7.0 x 10 8 CFU / g, achromobacter 1.0 x 10 8 ~ 4.5 x 10 9 CFU / g, methyl bacillus 1.5 x 10 7 ~ 2.5 x 10 8 CFU / g, sphingomonas 4.5 x 10 7 ~ 3.0 x 10 8 CFU / g and microbacterium 7.5 x 10 7 ~ 3.5 x 10 8 CFU / g.

[0027] Further preferably, the number of viable bacteria of each microorganism in the carbon-based microbial agent is respectively: chitin bacteria 4.7 x 10 8 ~ 1.6 x 10 9CFU / g, Bacillus 2.5 x 10 8 ~ 6.7 x 10 8 CFU / g, Achromobacter 1.3 x 10 8 ~ 4.0 x 10 9 CFU / g, Methylobacterium 1.7 x 10 7 ~ 2.2 x 10 8 CFU / g, Sphingomonas 5.0 x 10 7 ~ 2.6 x 10 8 CFU / g, and Microbacterium 7.7 x 10 7 ~ 3.3 x 10 8 CFU / g.

[0028] More preferably, Chitinophaga 9.4 x 10 8 ~ 1.2 x 10 9 CFU / g, Bacillus 5.2 x 10 8 ~ 6.7 x 10 8 CFU / g, Achromobacter 3.1 x 10 8 ~ 4.0 x 10 9 CFU / g, Methylobacterium 1.2 x 10 8 ~ 1.4 x 10 8 CFU / g, Sphingomonas 9.3 x 10 7 ~ 1.1 x 10 8 CFU / g, and Microbacterium 7.7 x 10 7 ~ 1.3 x 10 8 CFU / g.

[0029] In a second aspect, the present application provides a preparation method of the carbon-based microbial agent of the first aspect, comprising the following steps:

[0030] (1) inoculate the microbial strains into the culture medium containing pollutants respectively, and obtain the screened and domesticated microbial strains through screening and domestication;

[0031] (2) inoculate the screened and domesticated microbial strains in step (1) into biochar for 18h-24h, and obtain the carbon-based microbial agent.

[0032] Preferably, the biochar in step (2) is biochar obtained after pyrolysis of plants, and the plants are selected from one or more of water hyacinth, wheat straw, corn straw, and sugarcane residue.

[0033] Further preferably, the biochar is selected from water hyacinth biochar.

[0034] Preferably, the pyrolysis temperature is 350°C-650°C.

[0035] Further preferably, the temperature of the pyrolysis is 400℃ to 500℃.

[0036] Preferably, the time of the pyrolysis is 2h to 5h.

[0037] Preferably, the amounts of the screened and acclimated microorganisms used in step (2) are as follows: 30 to 60 parts of the enriched and acclimated chitin bacteria, 8 to 30 parts of the enriched and acclimated bacillus, 8 to 30 parts of the enriched and acclimated achromobacter, 1 to 15 parts of the enriched and acclimated methylobacterium, 1 to 15 parts of the enriched and acclimated sphingomonas, and 3 to 20 parts of the enriched and acclimated microbacterium, in terms of mass fraction.

[0038] Further preferably, the amounts of the screened and acclimated microorganisms used in step (2) are as follows: 35 to 50 parts of the enriched and acclimated chitin bacteria, 10 to 25 parts of the enriched and acclimated bacillus, 10 to 20 parts of the enriched and acclimated achromobacter, 2 to 10 parts of the enriched and acclimated methylobacterium, 3 to 10 parts of the enriched and acclimated sphingomonas, and 5 to 15 parts of the enriched and acclimated microbacterium, in terms of mass fraction.

[0039] Preferably, both the screening and acclimation in step (1) and the incubation in step (2) are carried out by using shaking culture, and the rotation speed of the shaking culture is 140rpm to 180rpm, and the temperature of the shaking culture is 25℃ to 35℃.

[0040] In a third aspect, the present application provides an application of the carbon-based microbial agent of the first aspect in the simultaneous degradation of halogenated organic pollutants and passivation of heavy metals in soil, wherein the halogenated organic pollutants include polybrominated diphenyl ethers and polychlorinated biphenyls, and the heavy metals include lead and cadmium.

[0041] In a fourth aspect, the present application provides a method for simultaneously degrading halogenated organic pollutants and passivating heavy metals, comprising the following steps: mixing the carbon-based microbial agent of the first aspect with a solid contaminated medium to obtain a mixture, which can simultaneously degrade halogenated organic pollutants and passivate heavy metals.

[0042] Preferably, the method further comprises controlling the water holding rate of the mixture to be 50wt% to 80wt%, the pH value of the mixture to be 6.5 to 7.5, and the temperature of the mixture to be 15℃ to 35℃.

[0043] Specifically, the water holding rate is the field water holding rate.

[0044] Preferably, the solid contaminated medium is one or more of the following: a composite contaminated soil and an industrial solid waste.

[0045] Preferably, the composite contaminated soil comprises polybrominated diphenyl ethers, polychlorinated biphenyls and heavy metal pollutants.

[0046] Preferably, the heavy metal pollutants are lead and / or cadmium.

[0047] Preferably, the polybrominated diphenyl ether content in the compound contaminated soil is 0.1 mg / kg to 10 mg / kg.

[0048] Preferably, the polychlorinated biphenyl content in the compound contaminated soil is 0.1 mg / kg to 10 mg / kg.

[0049] Preferably, the lead content in the compound contaminated soil is 100 mg / kg to 600 mg / kg.

[0050] Preferably, the cadmium content in the compound contaminated soil is 1 mg / kg to 10 mg / kg.

[0051] Preferably, the mass ratio of the carbon-based microbial agent and the solid contaminated medium is 0.8:100 to 20:100.

[0052] Further preferably, the mass ratio of the carbon-based microbial agent and the solid contaminated medium is 1:100 to 5:100.

[0053] Preferably, the time for simultaneous degradation of halogenated organic pollutants and passivation of heavy metals is 40 to 120 days.

[0054] Further preferably, the time for simultaneous degradation of halogenated organic pollutants and passivation of heavy metals is 60 to 100 days.

[0055] The beneficial effects of the present application are: the carbon-based microbial agent provided by the present application is to fix 6 strains of domesticated bacteria on biochar materials, the preparation method of the carbon-based microbial agent is good in repeatability, and the carbon-based microbial agent can simultaneously degrade halogenated organic pollutants and passivate heavy metals, and is suitable for practical application. Specifically:

[0056] (1) The present application combines 6 bacterial strains in a specific ratio and fixes them on biochar materials to obtain a carbon-based microbial agent, which can efficiently degrade halogenated organic pollutants and passivate heavy metals, can be used for the treatment and remediation of polybrominated diphenyl ether / polychlorinated biphenyl-heavy metal compound contaminated soil environment, can effectively reduce the harm of heavy metals and polybrominated diphenyl ether / polychlorinated biphenyl to the ecological environment and human health in electronic waste disassembly areas, mining waste areas, sewage irrigation areas and other contaminated soils;

[0057] (2) The spore-forming bacteria in the carbon-based microbial agent can better adsorb heavy metals in the soil, the achromobacter can degrade persistent organic pollutants such as polychlorinated biphenyl, and has a certain fixing effect on heavy metals Cd, Cu and the like. The chitin bacteria can decompose chitin in the environment and produce polysaccharides to promote the growth and development of plants, the methyl bacteria have a good degradation effect on polybrominated biphenyl ether, the sphingomonas can degrade polycyclic aromatic hydrocarbons, cellulose and the like, and the microbacterium can degrade organic matters such as polybrominated biphenyl ether and produce organic acids and amino acids and the like. In addition, the biochar not only provides nutrient substances and attachment sites for the six kinds of bacteria in the microbial agent, ensures the activity of the microorganisms in the microbial agent, but also greatly stimulates the interaction between the six kinds of bacteria, can improve the physical and chemical properties of the soil, and promotes the rapid repair of the contaminated soil.

[0058] (3) Compared with the traditional physical and chemical repair method, the carbon-based microbial agent provided by the application has the advantages of good treatment effect, low cost, small disturbance and environmental protection in the treatment of polybrominated biphenyl ether (and / or polychlorinated biphenyl) and heavy metal soil pollution.

[0059] (4) The carbon-based microbial agent provided by the application can rapidly and efficiently repair the heavy metal-organic matter contaminated site soil, and the degradation rate of 2,2',4,4'-tetrabromobiphenyl ether (BDE-47) in the actual electronic waste disassembly area composite contaminated soil can reach 89.60%; the degradation rate of 2,2',3,4,4',5,5'-heptachlorobiphenyl (PCB 180) can reach 94.99%; and the passivation rates of heavy metals lead and cadmium can reach 76.39% and 90.37% respectively.

[0060] (5) The carbon-based microbial agent of the application has no secondary pollution and is convenient to recycle, and can have a wide application prospect in the field of environmental repair. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 SEM images of the water hyacinth biochar, free bacteria in the free bacteria microbial agent and the water hyacinth biochar-based microbial agent in Example 2.

[0062] Figure 2 A passivation effect comparison chart of different materials on heavy metal lead in tetrabromobiphenyl ether-lead composite contaminated soil in Example 7.

[0063] Figure 3 A degradation effect comparison chart of different materials on 2,2',4,4'-tetrabromobiphenyl ether in tetrabromobiphenyl ether-lead composite contaminated soil in Example 7.

[0064] Figure 4 A passivation effect comparison chart of different materials on heavy metal cadmium in pentachlorobiphenyl-cadmium composite contaminated soil in Example 8.

[0065] Figure 5A comparison chart of the degradation effects of different materials in Example 8 on 2,3',4,4',5-pentachlorobiphenyl in cadmium-pentachlorobiphenyl composite contaminated soil.

[0066] Figure 6 A comparison chart of the passivation effects of different materials in Example 9 on heavy metal cadmium in composite contaminated soil.

[0067] Figure 7 A comparison chart of the degradation effects of different materials in Example 9 on 2,2',3,4,4',5,5'-heptachlorobiphenyl in composite contaminated soil.

[0068] Figure 8 A comparison chart of the remediation effects of different materials in the application on composite contaminated soil in the electronic waste disassembly area. DETAILED DESCRIPTION

[0069] The content of the application is further described in detail through specific examples.

[0070] The inorganic culture medium in the application is mixed and dissolved by water and various inorganic salts, and each liter of the inorganic culture medium contains: K2HPO4 2.8-3.2 g, KH2PO4 1.2-1.8 g, (NH4)2SO4 0.8-1.2 g, NaCl 0.4-0.6 g, and trace element solution 2 mL. The composition of the trace element solution is as follows: MgSO4 3.8-4.3 g, CuSO4 0.8-1.2 g, MnSO4 0.8-1.2 g, FeSO4·7H2O 0.8-1.2 g, CaCl2 0.8-1.2 g, and distilled water 1 L.

[0071] The inorganic salt liquid medium containing cadmium in the application is only different from the inorganic culture medium in that the inorganic salt liquid medium containing cadmium adds cadmium nitrate.

[0072] The inorganic salt liquid medium containing 2,2',3,4,4',5,5'-heptachlorobiphenyl (i.e. PCB 180) in the application is only different from the inorganic culture medium in that the inorganic salt liquid medium containing 2,2',3,4,4',5,5'-heptachlorobiphenyl adds PCB 180.

[0073] The inorganic salt liquid medium containing 2,2',4,4'-tetrabromodiphenyl ether-cadmium in the application (i.e. the inorganic salt liquid medium containing BDE-47-Cd) is only different from the inorganic salt liquid medium in that the inorganic salt liquid medium containing BDE-47-Cd adds BDE-47 and cadmium nitrate.

[0074] The difference between the inorganic salt liquid medium of the complex pollutant in the application and the inorganic salt liquid medium is that the inorganic salt liquid medium of the complex pollutant is added with pollutants, and the pollutants are selected from one or more of BDE-47, PCB 180, PCB 118 (i.e. 2,3',4,4',5-pentachlorobiphenyl), Cd, Pb, and the specific composition and concentration of the pollutants are described in each embodiment.

[0075] Unless otherwise specified, the beef extract peptone liquid medium in the application includes beef extract 2.8-3.2 g, peptone 9.5-10.5 g, NaCl 4.8-5.3 g, pH 6.8-7.3, and the rest is water; and the beef extract peptone solid medium is added with agar 18-25 g on the basis of the beef extract peptone liquid medium.

[0076] Example 1

[0077] The present embodiment provides a method for enriching, purifying, screening and identifying Bacillus sp. HY-1, Achromobacter sp. YH-1, Chitinophaga sp. MH-1 and Methylorubrum sp. ZY-1, which comprises the following steps:

[0078] 1. Domestication and screening of strains:

[0079] (1) 5 g of contaminated soil (longitude: 23.54 °N, latitude 113.04 °E, and the average content of pollutants: PCB 180 is 0.46 mg / kg, BDE-47 is 0.12 mg / kg, DTPA extractable Cd is 4.27 mg / kg, and DTPA extractable Pb is 178 mg / kg) collected from Longtang Town, Qingyuan, Guangdong, China, was added to 20 mL of inorganic salt medium, and cultured in a constant temperature shaking incubator (30 °C, 160 rpm) for 4 h, then taken out and stood for 30 min to obtain the supernatant, and the supernatant was used as the inoculum mother liquor;

[0080] (2) 5 mL-10 mL of the inoculum mother liquor in step (1) was inoculated into 100 mL of the initial inorganic salt liquid medium containing cadmium (Cd concentration was 1 mg / L), and then cultured in a constant temperature shaking incubator (30 °C, 5 d, 160 rpm), to obtain the first culture liquid;

[0081] Take 5mL-10mL of primary culture bacteria liquid to inoculate into secondary inorganic salt liquid medium containing cadmium (Cd concentration is 1.5mg / L), and culture in constant temperature shaking incubator (30℃, time is 5d, rotation speed is 160rpm) to obtain secondary culture bacteria liquid;

[0082] The control secondary inorganic salt liquid medium containing cadmium is based on the initial inorganic salt liquid medium containing cadmium, and the concentration of Cd is increased to 1.5mg / L, and the rest of the components are unchanged. After each generation of culture, the concentration of Cd in the inorganic salt liquid medium containing cadmium is increased by 0.5mg / L. In this way, the above steps are repeated for 5 generations of continuous culture until the concentration of Cd reaches 3mg / L, and the bacteria liquid after 5 generations of culture (i.e. five times culture bacteria liquid) is obtained.

[0083] (3) Take the bacteria liquid after 5 generations of culture in step (2), and use the dilution gradient method and the plate coating method to separate and purify the strain, select the better growing colonies, and obtain a single strain, i.e. Bacillus sp. HY-1. Inoculate it into beef extract peptone solid culture medium and store it in a-20℃ refrigerator for later use.

[0084] The difference between Achromobacter sp. YH-1 and Bacillus sp. HY-1 in domestication and screening is that in step (2) of the domestication and screening of Achromobacter sp. YH-1, the culture medium is selected as 100mL of initial inorganic salt liquid medium containing 2,2',3,4,4',5,5'-heptachlorobiphenyl (PCB 180) (i.e. initial inorganic salt liquid medium containing PCB 180, PCB 180 concentration is 1mg / L). After each generation of culture, the concentration of PCB 180 in the inorganic salt liquid medium containing PCB 180 is increased by 0.5mg / L. Thus, Achromobacter sp. YH-1 is obtained.

[0085] The difference between Chitinophaga sp. MH-1 and Bacillus sp. HY-1 in domestication and screening is that in step (2) of the domestication and screening of Chitinophaga sp. MH-1, the culture medium is selected as 100mL of inorganic salt liquid medium (i.e. inorganic salt liquid medium). After each generation of culture, the same inorganic salt liquid medium is replaced. Thus, Chitinophaga sp. MH-1 is screened.

[0086] The difference between the domestication and screening of Methylorubrum sp. ZY-1 and Bacillus sp. HY-1 lies in that in the domestication and screening step (2) of Methylorubrum sp. ZY-1, the culture medium is selected as an initial 2,2',4,4'-tetrabromodiphenyl ether-cadmium inorganic salt liquid culture medium (i.e. an initial BDE-47-Cd inorganic salt liquid culture medium, the BDE-47 concentration of which is 1 mg / L and the Cd concentration of which is 1 mg / L). The concentrations of BDE-47 and Cd in the BDE-47-Cd inorganic salt liquid culture medium are both increased to 1.5 mg / L after each generation of cultivation. Thus, Methylorubrum sp. ZY-1 is obtained.

[0087] 2. Identification of the degradation strain:

[0088] (1) Morphological characteristics of the bacterial cells and colonies

[0089] Gram staining and morphological identification are performed on each strain after the domestication and screening of the present example. Bacillus sp. HY-1 is Gram-positive, and its external morphology is observed. The colony is milky white, relatively viscous, irregular in edge, and opaque round in surface. Achromobacter sp. YH-1 is Gram-negative, and its external morphology is observed. The colony is light yellow, wet, droplet-shaped, smooth, irregular in edge, and translucent round in surface. Chitinophaga sp. MH-1 is Gram-negative, and its external morphology is observed. The colony is yellow, wet and viscous, jagged in edge, and opaque round in surface. Methylorubrum sp. ZY-1 is Gram-negative, and its external morphology is observed. The colony is pink, smooth, regular in edge, and needlepoint-sized, and opaque round in surface.

[0090] (2) 16S rDNA sequence

[0091] It can be known from the 16S rDNA sequence determination and analysis comparison of each strain after the domestication and screening of the present example that the sequence of Bacillus sp. HY-1 is 100% homologous to the 16S rDNA sequence of Bacillus, and therefore the strain is determined as Bacillus. The 16S rDNA sequence of Bacillus sp. HY-1 can be found in the genebank database with the accession number OP703374.

[0092] The sequence of Achromobacter sp. YH-1 is 99.8% homologous to the 16S rDNA sequence of Achromobacter. The strain is identified as Achromobacter, and its 16S rDNA sequence can be found in the genebank database with accession number OP703375.

[0093] The sequence of Chitinophaga sp. MH-1 is 99.4% homologous to the 16S rDNA sequence of Chitinophaga. The strain is identified as Chitinophaga, and named Chitinophaga sp. MH-1. Its 16S rDNA sequence can be found in the genebank database with accession number OP703376.

[0094] The sequence of Methylorubrum sp. ZY-1 is 100% homologous to the 16S rDNA sequence of Methylorubrum. The strain is identified as Methylorubrum, and named Methylorubrum sp. ZY-1. Its 16S rDNA sequence can be found in the genebank database with accession number OP703377.

[0095] Example 2

[0096] The present embodiment provides a method for domesticating a strain, comprising the following steps:

[0097] (1) Activation of the strain: a single strain is inoculated into 90 mL to 120 mL of beef extract peptone liquid medium from a beef extract peptone solid medium plate for storing the strain using an inoculation loop, and then placed in a constant temperature shaking incubator (30°C, 160 rpm) for 24 h to obtain a bacterial suspension (for standby use);

[0098] (2) Enrichment and domestication of the strain: 5 mL of the bacterial suspension in step (1) is inoculated into 100 mL of an initial complex contaminant inorganic salt liquid medium (the BDE-47 concentration of the medium is 1 mg / L, the PCB 180 concentration is 1 mg / L, and the Cd concentration is 2 mg / L), and then placed in a constant temperature shaking incubator (set parameters: temperature 30°C, rotation speed 160 rpm) for 120 h to obtain a bacterial liquid after primary domestication;

[0099] 5 mL of the primary culture bacterial liquid is inoculated into 100 mL of a secondary complex contaminant inorganic salt liquid medium, and then placed in a constant temperature shaking incubator (set parameters: temperature 30°C, rotation speed 160 rpm) for 120 h to obtain a bacterial liquid after secondary domestication;

[0100] The control secondary acclimated bacteria liquid is based on the initial complex pollutant inorganic salt liquid medium, the concentration of BDE-47, PCB 180 and Cd is increased by 1 mg / L, the rest of the components are unchanged, and the concentration of BDE-47, PCB 180 and Cd in the complex pollutant inorganic salt liquid medium is increased by 1 mg / L after each generation of culture;

[0101] By analogy, the above steps are repeated for continuous culture for 10 generations until the concentrations of BDE-47, PCB 180 and Cd reach 10 mg / L, and the bacteria liquid after 10 generations of culture (i.e. the bacteria liquid after ten times of acclimation) is obtained.

[0102] (3) Preservation of the strain: take the bacteria liquid after 10 generations of culture in step (2) and inoculate it into a beef extract peptone liquid medium (inoculation amount: 1-2 loop inoculation loops), and culture it in a constant temperature shaking incubator for 12 h (30°C, 160 rpm), then transfer the culture liquid to a sterile test tube and store it in sterile liquid paraffin, and store it at -20°C for long-term preservation, and obtain the acclimated strain.

[0103] The Bacillus sp. HY-1 in Example 1, the Achromobacter sp. YH-1 in Example 1, the Chitinophaga sp. MH-1 in Example 1, the Methylorubrum sp. ZY-1 in Example 1, the microbacterium sp. disclosed in patent application publication No. CN110511881A and the Sphingomonas sp. GY-1 disclosed in patent application publication No. CN110257280A are acclimated by using the acclimation method described in this embodiment, and six kinds of preserved acclimated strains are obtained.

[0104] The present embodiment provides a preparation method of a carbon-based microbial agent for simultaneously degrading halogenated organic matter and passivating heavy metals, comprising the following steps:

[0105] (1) Activation of the strain: take 0.2 mL of each of the six preserved acclimated strains and inoculate them into six 100 mL beef extract peptone liquid media, and enrich and culture them in a constant temperature shaking incubator (30°C, 160 rpm) for 24 h, to obtain six acclimated and enriched bacterial suspensions;

[0106] (2) Preparation of biochar: After the dried water hyacinth biomass is crushed, it is placed in a ceramic crucible, compacted, and covered with a lid. It is then placed in a tube furnace and pyrolyzed under the following conditions: temperature of 500°C, retention time of 4h, and anoxic conditions (oxygen concentration less than XX). The biochar is then washed with deionized water to remove surface ash and reduce its alkalinity, which is beneficial for the attachment and fixation of bacterial strains on its surface and protects bacterial viability. Finally, the biochar is dried, ground using a ball mill, and sieved through a 150-mesh sieve to obtain water hyacinth biochar.

[0107] (3) Preparation of free bacterial inoculant: The enriched bacterial suspension from step (1) is mixed according to the following mass fractions: 50 parts of chitin bacteria, 10 parts of bacillus, 20 parts of achromobacter, 2 parts of methyl bacteria, 8 parts of sphingomonas, and 10 parts of microbacterium. The resulting free bacterial inoculant is obtained.

[0108] The viable bacterial counts of each microorganism in the free bacterial inoculant are as follows: chitin bacteria 6.5×10 8 ~ 9.1×10 8 CFU / g, bacillus 1.3×10 8 ~ 1.8×10 8 CFU / g, achromobacter 2.6×10 8 ~ 3.6×10 8 CFU / g, methyl bacteria 2.5×10 7 ~ 3.8×10 7 CFU / g, sphingomonas 1.0×10 8 ~ 1.5×10 8 CFU / g, and microbacterium 1.3×10 8 ~ 1.8×10 8 CFU / g.

[0109] (4) Preparation of carbon-based bacterial inoculant: 1g of water hyacinth biochar from step (2) is placed in a high-sterilization pot and subjected to sterilization treatment at 121°C for 30 minutes. After cooling to room temperature, the sterilized water hyacinth biochar is obtained.

[0110] The sterilized water hyacinth biochar is thoroughly mixed with 30mL of the free bacterial inoculant from step (3), and then placed in a constant-temperature shaking incubator (30°C, 160rpm) for 18-24h. The culture medium liquid is removed by filtration, and then washed with sterile water. The carbon-based bacterial inoculant is obtained by vacuum freeze-drying.

[0111] Quantitative analysis and morphology analysis of materials:

[0112] (1) The carbon-based bacterial inoculant is analyzed using the dilution plate count method, and the viable bacterial counts of each microorganism are as follows: chitin bacteria 1.3×10 9~ 1.6 x 10 9 CFU / g, Bacillus 2.6 x 10 8 ~ 3.3 x 10 8 CFU / g, Achromobacter 5.1 x 10 8 ~ 6.6 x 10 8 CFU / g, Methylobacterium 5.3 x 10 7 ~ 6.9 x 10 7 CFU / g, Sphingomonas 2.1 x 10 8 ~ 2.6 x 10 8 CFU / g, and Microbacterium 2.2 x 10 8 ~ 3.3 x 10 8 CFU / g.

[0113] (2) The Scanning Electron Microscope (SEM) images of the water hyacinth biochar, free bacteria in the free bacteria agent, and the water hyacinth biochar-based bacterial agent in this embodiment are shown in Figure 1 , in which A is the SEM image of the water hyacinth biochar, the magnification is x2000; B is the SEM image of the free bacteria in the free bacteria agent, the magnification is x10000; and C is the SEM image of the water hyacinth biochar-based bacterial agent, the magnification is x5000.

[0114] It can be seen from Figure 1 that the water hyacinth biochar material itself obviously has a rich pore channel structure (the pore channel structure size is in the micron level, and the pore diameter size is about 1 μm-20 μm), and the surface of the water hyacinth biochar material is relatively rough, so as to facilitate the firm attachment and enrichment culture of the micron-level organisms (see A and C in Figure 1 ); the free bacteria in the free bacteria agent are mainly bacillus bacteria (see B in Figure 1 ). Figure 1 C in shows that a large number of bacterial bodies are attached to the surface of the water hyacinth biochar material and the micron-level pore structure, which not only indicates that the water hyacinth biochar can provide a larger habitat for the free bacteria in the free bacteria agent and maintain the normal physiological metabolism of the bacterial strain, but also indicates that the preparation method of this embodiment can successfully prepare the carbon-based bacterial agent.

[0115] Example 3

[0116] The embodiment provides a preparation method of a carbon-based microbial agent for synchronously degrading halogenated organic matters and passivating heavy metals, which is only different from the method in embodiment 2 in that the mixed inoculum of the enriched strains in step (3) is mixed according to the following mass fractions, and the amounts of various microorganisms are as follows: 35 parts of chitin bacteria, 30 parts of bacillus, 10 parts of achromobacter, 7 parts of methyl bacillus, 10 parts of sphingomonas, and 8 parts of microbacterium, to obtain a free bacterial inoculum, and the method specifically comprises the following steps:

[0117] (1) Activation of the strains: 0.2 mL of each of the six preserved and enriched strains in embodiment 2 is inoculated into six 100 mL beef extract proteose peptone liquid culture media, and then enriched culture is carried out in a constant-temperature vibration incubator (30 DEG C, 160 rpm) for 24 h, to obtain six enriched bacterial suspensions;

[0118] (2) Preparation of the biochar: dried water hyacinth biomass is crushed, placed in a ceramic crucible, compacted, covered with a lid, and then placed in a tube furnace for pyrolysis under the conditions of a temperature of 500 DEG C, a retention time of 4 h and anoxic (oxygen concentration is lower than 0.5 %), and then washed with deionized water to remove ash on the surface of the biochar and reduce the alkalinity of the biochar (which is beneficial to the attachment and fixation of the bacterial strains on the surface of the biochar and the protection of the bacterial activity), and finally dried, ground by a ball mill, and sieved through a 150-mesh sieve, to obtain water hyacinth biochar;

[0119] (3) Preparation of the free bacterial inoculum: the enriched bacterial suspension in step (1) is mixed according to the following mass percentages: 35 parts of chitin bacteria, 30 parts of bacillus, 10 parts of achromobacter, 7 parts of methyl bacillus, 10 parts of sphingomonas, and 8 parts of microbacterium, to obtain a free bacterial inoculum;

[0120] The viable cell counts of the microorganisms in the free bacterial inoculum are as follows: 2.4 x 10 8 ~ 3.3 x 10 8 CFU / g of chitin bacteria, 2.0 x 10 8 ~ 2.8 x 10 8 CFU / g of bacillus, 6.7 x 10 7 ~ 9.4 x 10 7 CFU / g of achromobacter, 4.7 x 10 7 ~ 6.6 x 10 7 CFU / g of methyl bacillus, 6.7 x 10 7 ~ 9.4 x 10 7 CFU / g of sphingomonas, and 5.4 x 10 7 ~ 7.5 x 10 7 CFU / g of microbacterium.

[0121] (4) Preparation of the carbon-based microbial agent: 1 g of the water hyacinth biochar in step (2) was placed in a high-sterilization pot and subjected to sterilization treatment at 121°C for 30 min, and then cooled to room temperature to obtain sterilized water hyacinth biochar;

[0122] The sterilized water hyacinth biochar and 30 mL of the free bacterial agent in step (3) were mixed well and then placed in a constant-temperature shaking incubator (30°C, 160 rpm) for 18-24 h of culture, the culture medium liquid was removed by filtration, and then washed with sterile water, and vacuum freeze-dried to obtain the carbon-based microbial agent.

[0123] Quantitative analysis of the material:

[0124] The carbon-based microbial agent was counted and analyzed by the dilution plate counting method, and the results showed that the viable cell counts of the various microorganisms in the carbon-based microbial agent were as follows: chitin bacteria 4.7 x 10 8 ~ 6.0 x 10 8 CFU / g, Bacillus 4.0 x 10 8 ~ 5.1 x 10 8 CFU / g, achromobacter 1.3 x 10 8 ~ 1.7 x 10 8 CFU / g, methyl bacteria 9.3 x 10 7 ~ 1.2 x 10 8 CFU / g, sphingomonas 1.3 x 10 8 ~ 1.7 x 10 8 CFU / g, and microbacterium 1.0 x 10 8 ~ 1.4 x 10 8 CFU / g.

[0125] Example 4

[0126] The present embodiment provides a method for preparing a carbon-based microbial agent for simultaneously degrading halogenated organic matter and passivating heavy metals, which is only different from the method of Example 2 in that the enriched bacterial suspension in step (3) is mixed according to the following mass fractions, and the amounts of various microorganisms are as follows: 40 parts of chitin bacteria, 15 parts of Bacillus, 17 parts of achromobacter, 10 parts of methyl bacteria, 3 parts of sphingomonas, and 15 parts of microbacterium, to obtain a free bacterial agent, which specifically comprises the following steps:

[0127] (1) Activation of the bacterial strains: 0.2 mL of each of the six preserved and enriched bacterial strains in Example 2 was inoculated into six 100 mL beef extract peptone liquid media, and then cultured in a constant-temperature shaking incubator (30°C, 160 rpm) for 24 h of enrichment to obtain six enriched bacterial suspensions.

[0128] (2) Preparation of biochar: After the dried water hyacinth biomass is crushed, it is placed in a ceramic crucible, compacted, and covered with a lid. It is then placed in a tube furnace and pyrolyzed under the following conditions: temperature of 500°C, retention time of 4h, and anoxic conditions (oxygen concentration less than 0.5%). The biochar is then washed with deionized water to remove surface ash and reduce its alkalinity, which is beneficial for the attachment and fixation of bacterial strains on its surface and protects bacterial viability. Finally, it is dried, ground using a ball mill, and sieved through a 150-mesh sieve to obtain water hyacinth biochar.

[0129] (3) Preparation of free bacterial inoculant: The enriched bacterial suspension from step (1) is mixed according to the following mass fractions: 40 parts of chitin bacteria, 15 parts of bacillus, 17 parts of achromobacter, 10 parts of methyl bacteria, 3 parts of sphingomonas, and 15 parts of microbacterium. The resulting free bacterial inoculant is obtained.

[0130] The viable bacterial counts of each microorganism in the free bacterial inoculant are as follows: chitin bacteria 3.4×10 8 ~ 4.7×10 8 CFU / g, bacillus 1.3×10 8 ~ 1.8×10 8 CFU / g, achromobacter 1.4×10 8 ~ 2.0×10 8 CFU / g, methyl bacteria 8.5×10 7 ~ 1.2×10 8 CFU / g, sphingomonas 2.5×10 7 ~ 3.6×10 7 CFU / g, and microbacterium 1.3×10 8 ~ 1.8×10 8 CFU / g.

[0131] (4) Preparation of carbon-based bacterial inoculant: 1g of water hyacinth biochar from step (2) is placed in a high-sterilization pot and subjected to sterilization treatment at 121°C for 30 minutes. After cooling to room temperature, the sterilized water hyacinth biochar is obtained.

[0132] The sterilized water hyacinth biochar is thoroughly mixed with 30mL of free bacterial inoculant from step (3), and then placed in a constant-temperature shaking incubator (30°C, 160rpm) for 18-24h. The culture medium liquid is removed by filtration, and then washed with sterile water. After vacuum freeze-drying, the carbon-based bacterial inoculant is obtained.

[0133] Quantitative analysis of materials:

[0134] The carbon-based bacterial inoculant is counted and analyzed using the dilution plate count method. The viable bacterial counts of each microorganism in the carbon-based bacterial inoculant are as follows: chitin bacteria 6.7×10 8 ~ 8.6×108 CFU / g, Bacillus 2.5 x 10 8 ~ 3.2 x 10 8 CFU / g, Achromobacter 2.8 x 10 8 ~ 3.7 x 10 8 CFU / g, Methylobacterium 1.7 x 10 7 ~ 2.2 x 10 8 CFU / g, Sphingomonas 5.0 x 10 7 ~ 6.4 x 10 7 CFU / g, and Microbacterium 2.5 x 10 8 ~ 3.2 x 10 8 CFU / g.

[0135] Example 5

[0136] The present example provides a preparation method of a carbon-based microbial agent for simultaneously degrading halogenated organic matter and passivating heavy metals, which is only different from that of Example 2 in that the mixed inoculum of the enriched bacteria in step (3) is mixed according to the following mass fractions, and the amounts of various microorganisms are as follows: 45 parts of chitin bacteria, 25 parts of Bacillus, 15 parts of Achromobacter, 5 parts of Methylobacterium, 5 parts of Sphingomonas, and 5 parts of Microbacterium, to obtain a free bacterial inoculum, which specifically comprises the following steps:

[0137] (1) Activation of bacterial strains: 0.2 mL of each of the six preserved enriched bacterial strains in Example 2 was inoculated into six 100 mL beef extract proteose peptone liquid medium, and cultured in an incubator (30°C, 160 rpm) for 24 h to obtain six enriched bacterial suspensions;

[0138] (2) Preparation of biochar: dried water hyacinth biomass was crushed and placed in a ceramic crucible, compacted, covered with a lid, and placed in a tube furnace for pyrolysis under the conditions of a temperature of 500°C, a retention time of 4 h, and anoxic (oxygen concentration less than 0.5%), then washed with deionized water to remove surface ash and reduce alkalinity (which is beneficial to the attachment and fixation of bacterial strains on the surface and protects the activity of the bacteria), and finally dried, ground with a ball mill, and sieved through a 150-mesh sieve to obtain water hyacinth biochar;

[0139] (3) Preparation of free bacterial inoculum: the enriched bacterial suspension in step (1) was mixed according to the following mass fractions, and the amounts of various microorganisms are as follows: 45 parts of chitin bacteria, 25 parts of Bacillus, 15 parts of Achromobacter, 5 parts of Methylobacterium, 5 parts of Sphingomonas, and 5 parts of Microbacterium, to obtain a free bacterial inoculum;

[0140] The viable cell counts of each microorganism in the free bacterial inoculum are as follows: chitin bacteria 4.8 x 10 8 ~ 6.7 x 108 CFU / g, Bacillus 2.7 x 10 8 ~ 3.7 x 10 8 CFU / g, Achromobacter 1.6 x 10 8 ~ 2.2 x 10 8 CFU / g, Methylobacterium 4.1 x 10 7 ~ 8.2 x 10 7 CFU / g, Sphingomonas 2.2 x 10 7 ~ 7.3 x 10 7 CFU / g, and Microbacterium 5.3 x 10 7 ~ 7.4 x 10 7 CFU / g.

[0141] (4) Preparation of the carbon-based microbial agent: 1 g of the water hyacinth biochar in step (2) was placed in a high-temperature sterilization pot and subjected to sterilization treatment at 121°C for 30 min, and then cooled to room temperature to obtain sterilized water hyacinth biochar;

[0142] The sterilized water hyacinth biochar and 30 mL of the free bacterial agent in step (3) were thoroughly mixed, and then placed in a constant-temperature shaking incubator (30°C, 160 rpm) for culture for 18-24 h. The culture medium liquid was removed by filtration, and then washed with sterile water. After vacuum freeze-drying, the carbon-based microbial agent was obtained.

[0143] Quantitative analysis of materials:

[0144] The carbon-based microbial agent was counted and analyzed by the dilution plate counting method, and the results showed that the viable cell counts of the microorganisms in the carbon-based microbial agent were as follows: Chitin 9.4 x 10 8 ~ 1.2 x 10 9 CFU / g, Bacillus 5.2 x 10 8 ~ 6.7 x 10 8 CFU / g, Achromobacter 3.1 x 10 8 ~ 4.0 x 10 9 CFU / g, Methylobacterium 1.2 x 10 8 ~ 1.4 x 10 8 CFU / g, Sphingomonas 9.3 x 10 7 ~ 1.1 x 10 8 CFU / g, and Microbacterium 7.7 x 10 7 ~ 1.3 x 10 8 CFU / g.

[0145] Example 6

[0146] The embodiment provides a preparation method of a carbon-based microbial agent for synchronously degrading halogenated organic matters and passivating heavy metals, which is only different from the method in embodiment 5 in that the preparation process of the biochar in step (2) is different, and specifically comprises the following steps:

[0147] (1) Activation of the strain: 0.2 mL of each of the six preserved domesticated strains in embodiment 2 is inoculated into 100 mL of a beef extract proteose peptone liquid medium, and then enriched and cultured in a constant-temperature vibration incubator (30 DEG C, 160 rpm) for 24 h, so as to obtain six domesticated and enriched bacterial suspensions;

[0148] (2) Preparation of the biochar: the air-dried wheat straw biomass, corn straw biomass and sugarcane residue biomass are respectively crushed, then respectively placed in a ceramic crucible, compacted, covered with a lid, and then placed in a tube furnace for pyrolysis under the conditions of a temperature of 500 DEG C, a retention time of 4 h and anoxic (oxygen concentration is lower than 0.5%), and then washed with deionized water to remove ash on the surface of the biochar and reduce the alkalinity of the biochar (this is beneficial to the attachment and fixation of the bacterial strains on the surface of the biochar and the protection of the bacterial activity), and finally dried, ground by a ball mill and sieved through a 150-mesh sieve, so as to obtain the wheat straw biochar, the corn straw biochar and the sugarcane residue biochar;

[0149] (3) Preparation of the free bacterial agent: the domesticated and enriched bacterial suspensions in step (1) are mixed according to the following mass fractions, and the amounts of various microorganisms are as follows: 45 parts of chitin bacteria, 25 parts of bacillus, 15 parts of achromobacter, 5 parts of methyl bacillus, 5 parts of sphingomonad and 5 parts of microbacterium, so as to obtain the free bacterial agent;

[0150] The viable cell counts of the microorganisms in the free bacterial agent are respectively as follows: 4.8 x 10 8 ~ 6.7 x 10 8 CFU / g of chitin bacteria, 2.7 x 10 8 ~ 3.7 x 10 8 CFU / g of bacillus, 1.6 x 10 8 ~ 2.2 x 10 8 CFU / g of achromobacter, 4.1 x 10 7 ~ 8.2 x 10 7 CFU / g of methyl bacillus, 2.2 x 10 7 ~ 7.3 x 10 7 CFU / g of sphingomonad and 5.3 x 10 7 ~ 7.4 x 10 7 CFU / g of microbacterium.

[0151] (4) Preparation of carbon-based microbial agent: 1 g of wheat straw biochar, 1 g of corn straw biochar, and 1 g of sugarcane residue biochar in step (2) were weighed, and then placed in a high-temperature sterilization pot. The sterilization treatment was performed at 121°C for 30 min, and then the temperature was reduced to room temperature to obtain the sterilization-treated wheat straw biochar, corn straw biochar, and sugarcane residue biochar;

[0152] The three kinds of sterilization-treated biochar were mixed with 30 mL of the free bacterial agent in step (3) respectively, and then placed in a constant-temperature shaking incubator (30°C, 160 rpm) for 18-24 h. The culture medium liquid was removed by filtration, and then washed with sterile water. The wheat straw biochar-based microbial agent, corn straw biochar-based microbial agent, and sugarcane residue biochar-based microbial agent were obtained by vacuum freeze-drying.

[0153] Quantitative analysis of materials:

[0154] The above three kinds of carbon-based microbial agents were counted and analyzed by the dilution plate counting method, and the results showed that the viable cell counts of each microorganism in the wheat straw biochar-based microbial agent, corn straw biochar-based microbial agent, and sugarcane residue biochar-based microbial agent met the following ranges: chitin bacteria 9.4×10 8 ~ 1.2×10 9 CFU / g, Bacillus 5.2×10 8 ~ 6.7×10 8 CFU / g, achromobacter 3.1×10 8 ~ 4.0×10 9 CFU / g, methyl bacteria 1.2×10 8 ~ 1.4×10 8 CFU / g, sphingomonas 9.3×10 7 ~ 1.1×10 8 CFU / g, and microbacterium 7.7×10 7 ~ 1.3×10 8 CFU / g.

[0155] Example 7

[0156] The present embodiment provides a method for testing the remediation effect of a test material on tetrabromobisphenol A-lead composite contaminated soil, which comprises the following steps:

[0157] (1) Preparation of tetrabromobisphenol A-lead composite contaminated soil:

[0158] The uncontaminated soil (determined to be free of PCB 180, BDE-47, and DTPA extractable Cd with an available state concentration of 0.01 mg / kg, and DTPA extractable Pb with an available state concentration of 5.65 mg / kg) was collected and added with a lead nitrate aqueous solution. After mixing by stirring, a 2,2',4,4'-tetrabromodiphenyl ether BDE-47 (purity of BDE-47 reagent >98%) n-hexane solution was added, and the concentration of Pb in the soil after mixing was controlled at 600 mg / kg, and the concentration of BDE-47 was controlled at 1 mg / kg. After solvent evaporation and aging for 2 months, the tetrabromodiphenyl ether-lead compound contaminated soil was obtained. 2+ The concentration of Pb in the soil after mixing was controlled at 600 mg / kg, and the concentration of BDE-47 was controlled at 1 mg / kg. After solvent evaporation and aging for 2 months, the tetrabromodiphenyl ether-lead compound contaminated soil was obtained.

[0159] The content of BDE-47 in the tetrabromodiphenyl ether-lead compound contaminated soil was determined by gas chromatography-mass spectrometry according to the standard of HJ 952-2018 Soil and Sediment Determination of Polybrominated Diphenyl Ethers by Gas Chromatography-Mass Spectrometry. The available state concentration of DTPA (diethylenetriaminepentaacetic acid) extractable Pb in the tetrabromodiphenyl ether-lead compound contaminated soil was determined by atomic absorption spectrometry according to the standard of GB / T17141-1997 Soil Quality Determination of Lead and Cadmium by Graphite Furnace Atomic Absorption Spectrophotometry.

[0160] Analysis shows that the content of BDE-47 in the tetrabromodiphenyl ether-lead compound contaminated soil is 0.94 mg / kg, and the available state concentration of DTPA extractable Pb (lead) in the tetrabromodiphenyl ether-lead compound contaminated soil is 522 mg / kg.

[0161] (2) Use, application, and efficacy evaluation of test materials:

[0162] Four groups of 500g of the tetrabromodiphenyl ether-lead compound contaminated soil in step (1) were taken and added to flowerpots, respectively, to obtain four groups of flowerpots containing tetrabromodiphenyl ether-lead compound contaminated soil. According to the mass ratio of tetrabromodiphenyl ether-lead compound contaminated soil to experimental material of 100:5, 25g of the carbon-based microbial agent in Example 2 was uniformly covered on the surface of the compound contaminated soil, and the microbial agent and the soil were mixed uniformly by stirring to obtain a carbon-based microbial agent experimental group. At the same time, 25g of water hyacinth biochar and 25g of free bacterial agent (i.e., the free bacterial agent in Example 2) were added to the other three groups of flowerpots containing tetrabromodiphenyl ether-lead compound contaminated soil as control groups, and a group of contaminated soil without adding any material was set as a blank control.

[0163] The above experimental groups and control groups were placed in a room temperature (20℃-25℃) for cultivation. During the cultivation process, the humidity of the soil was maintained at 65%-75% of the field moisture capacity. After 15d, 30d, 45d, 60d, and 90d of cultivation, the residual amount of BDE-47 and the available state content of DTPA extractable Pb in the soil were determined.

[0164] It should be noted that the calculation method of BDE-47 removal rate and Pb passivation rate in the present application is as follows:

[0165] BDE-47 removal rate (%) = (initial BDE-47 concentration - real-time BDE-47 concentration) / initial BDE-47 concentration x 100%;

[0166] Pb passivation rate (%) = (initial Pb concentration - real-time Pb concentration) / initial Pb concentration x 100%.

[0167] Test results:

[0168] The passivation effect of different materials on heavy metal lead in the composite contaminated soil in the present embodiment is shown in the comparison chart as shown in Figure 2 The degradation effect of different materials on 2,2',4,4'-tetrabromodiphenyl ether in the composite contaminated soil in the present embodiment is shown in the comparison chart as shown in Figure 3

[0169] As shown in Figure 2 and Figure 3 It can be seen that: compared with the biochar control and free bacterial agent control group, the carbon-based bacterial agent in Example 2 shows good repair effect on the composite contaminated soil containing 0.94 mg / kg BDE-47 and 522 mg / kg lead. When the repair time is 15 d, 30 d, 45 d, 60 d, 90 d, the above detection and analysis can know that the BDE-47 removal rate in the composite contaminated soil can reach 17.79%, 39.03%, 48.61%, 53.29%, 67.43%; the passivation rate of lead in the composite contaminated soil can reach 44.54%, 58.29%, 59.66%, 60.42%, 68.54%. This shows that compared with the free bacterial agent control, the carbon-based bacterial agent can simultaneously greatly promote the degradation of BDE-47 and the passivation of heavy metal lead in the composite contaminated soil.

[0170] Example 8

[0171] The present embodiment provides a method for testing the repair effect of a material on pentachlorobiphenyl-cadmium composite contaminated soil, which comprises the following steps:

[0172] (1) Preparation of pentachlorobiphenyl-cadmium composite contaminated soil:

[0173] Collect soil around the electronic waste disassembly site in Longtang Town, Qingyuan, Guangdong, which has not been contaminated, and add cadmium nitrate aqueous solution to it, mix by stirring, then add 2,3',4,4',5-pentachlorobiphenyl PCB 118 n-hexane solution (the purity of PCB 118 reagent is > 98%), and control the Cd 2+ ​The concentration of 1.50 mg / kg, 2, 3', 4, 4', 5-pentachlorobiphenyl (PCB 118) is 0.3 mg / kg; and finally, after solvent evaporation and aging for 2 months, pentachlorobiphenyl-cadmium composite contaminated soil is obtained.

[0174] According to the standard of HJ 922-2017 Determination of Polychlorinated Biphenyls in Soil and Sediment by Gas Chromatography, the content of PCB 118 in pentachlorobiphenyl-cadmium composite contaminated soil is determined by gas chromatography-mass spectrometry. According to the standard of GB / T 17141-1997 Determination of Lead and Cadmium in Soil by Graphite Furnace Atomic Absorption Spectrometry, the effective concentration of DTPA (diethylenetriaminepentaacetic acid) extracted Cd in pentachlorobiphenyl-cadmium composite contaminated soil is determined by atomic absorption spectrometry.

[0175] Analysis shows that the content of PCB 118 in pentachlorobiphenyl-cadmium composite contaminated soil is 0.26 mg / kg, and the effective concentration of DTPA extracted Cd (cadmium) in pentachlorobiphenyl-cadmium composite contaminated soil is 1.35 mg / kg.

[0176] (2) Use and efficacy evaluation of test materials:

[0177] Take 4 groups of 500g pentachlorobiphenyl-cadmium composite contaminated soil in step (1) and put them into flowerpots to obtain 4 groups of flowerpots containing pentachlorobiphenyl-cadmium composite contaminated soil; according to the mass ratio of pentachlorobiphenyl-cadmium composite contaminated soil to experimental material of 100:2, 10g of carbon-based microbial agent in Example 3 is evenly covered on the surface of the composite contaminated soil and fully stirred to mix the microbial agent with the soil to obtain a carbon-based microbial agent experimental group; at the same time, 3 groups of flowerpots containing pentachlorobiphenyl-cadmium composite contaminated soil are respectively added with the same mass of water hyacinth biochar and free bacterial inoculum (i.e. free bacterial inoculum in Example 3) as control groups, and a contaminated soil without adding any material is set as a blank control.

[0178] The above experimental groups and control groups are placed in a room temperature (20℃-25℃) for cultivation, and during the cultivation process, the humidity of the soil is maintained at 65%-75% (mass fraction) of the field moisture capacity; after 15d, 30d, 45d, 60d and 90d of cultivation, the residual amount of PCB 118 and the effective content of DTPA extracted Cd in the soil are determined.

[0179] It should be noted that the calculation method of PCB 118 removal rate and Cd passivation rate in the present application is as follows:

[0180] PCB 118 removal rate (%) = (initial PCB 118 concentration - real-time PCB 118 concentration) / initial PCB 118 concentration x 100%;

[0181] Cd passivation rate (%) = (initial Cd concentration - real-time Cd concentration) / initial Cd concentration × 100%.

[0182] The comparison diagram of the passivation effects of different materials on cadmium in composite contaminated soil in this embodiment is shown in the figure. Figure 4 As shown in the figure. This embodiment compares the degradation effects of different materials on 2,3',4,4',5-pentachlorobiphenyl in composite contaminated soil. Figure 5 As shown.

[0183] Depend on Figure 4 and Figure 5 It can be seen that, compared with the biochar control and the free bacterial agent control group, the carbon-based bacterial agent in Example 3 is more effective against bacteria containing 1.50 mg / kg Cd. 2+ The combined contaminated soil treated with 0.3 mg / kg 2,3',4,4',5-pentachlorobiphenyl (PCB 118) showed good remediation effects. When the remediation time was 15 days, 30 days, 45 days, 60 days, and 90 days, the above tests and analyses showed that the removal rate of PCB 118 in the combined contaminated soil reached 9.83%, 26.45%, 32.73%, 54.39%, and 57.82%, respectively; the cadmium passivation rate in the combined contaminated soil reached 28.15%, 46.69%, 49.01%, 58.98%, and 74.18%, respectively. This indicates that compared with the free bacterial agent control, the carbon-based bacterial agent can simultaneously and significantly promote the degradation of PCB 118 and the passivation of the heavy metal cadmium in the combined contaminated soil.

[0184] Example 9

[0185] This embodiment provides a method for testing the remediation effect of materials on soil contaminated with heptachlorobiphenyl-cadmium composites, which includes the following steps:

[0186] (1) Preparation of soil contaminated with heptachlorobiphenyl-cadmium complex:

[0187] Uncontaminated soil samples were collected from the vicinity of an electronic waste dismantling site in Longtang Town, Qingyuan City, Guangdong Province. A cadmium nitrate aqueous solution was added to the soil, and after thorough mixing, a hexane solution of 2,2',3,4,4',5,5'-heptachlorobiphenyl (PCB 180) (PCB 180 reagent purity > 98%) was added. The Cd content in the mixed soil was controlled. 2+ The soil was contaminated with heptachlorobiphenyl and cadmium by solvent evaporation and aging for 2 months. The concentration of 2,2',3,4,4',5,5'-heptachlorobiphenyl (i.e., PCB 180) was 5 mg / kg.

[0188] According to the standard of HJ 922-2017, the content of PCB 180 in the heptachlorobiphenyl-cadmium composite contaminated soil was determined by gas chromatography-mass spectrometry. According to the standard of GB / T 17141-1997, the effective concentration of DTPA (i.e. diethylenetriaminepentaacetic acid) extracted Cd in the heptachlorobiphenyl-cadmium composite contaminated soil was determined by atomic absorption spectrometry.

[0189] Analysis shows that the content of PCB 180 in the heptachlorobiphenyl-cadmium composite contaminated soil is 0.98 mg / kg, and the effective concentration of DTPA extracted Cd (i.e. cadmium) in the heptachlorobiphenyl-cadmium composite contaminated soil is 4.60 mg / kg.

[0190] (2) Use and efficacy evaluation of test materials:

[0191] Four groups of 500g heptachlorobiphenyl-cadmium composite contaminated soil in step (1) were taken and added to flowerpots to obtain four groups of flowerpots containing heptachlorobiphenyl-cadmium composite contaminated soil; 15g of the carbon-based microbial agent in Example 4 was evenly applied on the surface of the composite contaminated soil according to a mass ratio of heptachlorobiphenyl-cadmium composite contaminated soil to experimental material of 100:3, and the microbial agent and the soil were fully mixed to obtain a carbon-based microbial agent experimental group; at the same time, water hyacinth biochar and free bacterial agent (i.e. the free bacterial agent in Example 4) were added to the other three groups of flowerpots containing heptachlorobiphenyl-cadmium composite contaminated soil as control groups, and a group of contaminated soil without any material was set as a blank control.

[0192] The above experimental groups and control groups were placed in a room at room temperature (20℃-25℃) for culture, and the humidity of the soil was maintained at 65%-75% of the field water holding capacity during the culture process; the residual amount of PCB 180 and the effective content of DTPA extracted Cd in the soil were determined after 15d, 30d, 45d, 60d and 90d of culture.

[0193] It should be noted that the calculation method of PCB 180 removal rate and Cd passivation rate in the present application is as follows:

[0194] PCB 180 removal rate (%) = (initial PCB 180 concentration - real-time PCB 180 concentration) / initial PCB 180 concentration x 100%;

[0195] Cd passivation rate (%) = (initial Cd concentration - real-time Cd concentration) / initial Cd concentration x 100%.

[0196] The passivation effect comparison chart of different materials on heavy metal cadmium in the composite contaminated soil in the present embodiment is as follows: Figure 6The degradation effect of different materials in the composite contaminated soil on 2,2',3,4,4',5,5'-heptachlorobiphenyl in the embodiment is shown in the following figure: Figure 7 As shown in the figure.

[0197] As shown in the figure. Figure 6 And Figure 7 It can be seen that, compared with the biochar control and free bacterial agent control groups, the carbon-based bacterial agent in Example 4 showed good repair effect on the composite contaminated soil containing 4.60 mg / kg Cd 2+ , 0.98 mg / kg 2,2',3,4,4',5,5'-heptachlorobiphenyl (i.e. PCB 180). When the repair time is 15d, 30d, 45d, 60d, 90d, the removal rate of PCB 180 in the composite contaminated soil can reach 20.73%, 28.27%, 45.36%, 49.88%, 53.00% through the above detection and analysis; The passivation rate of cadmium in the composite contaminated soil can reach 17.73%, 24.43%, 36.15%, 48.12%, 55.70%. This shows that compared with the free bacterial agent control, the carbon-based bacterial agent can greatly promote the degradation of PCB 180 and the passivation of heavy metal cadmium in the composite contaminated soil at the same time.

[0198] Comparative Example 1

[0199] The present comparative example provides a preparation method of a non-acclimated water hyacinth carbon-based bacterial agent, which is only different from Example 5 in that the bacteria used are not subjected to the acclimation process in Example 2, and specifically comprises the following steps:

[0200] (1) Activation of the strain: 0.2 mL of 6 kinds of preserved strain beef extract peptone solid medium plates were inoculated with a single strain using an inoculation loop, and then inoculated into 90 mL-120 mL of beef extract peptone liquid medium, and then placed in a constant temperature shaking incubator (30°C, 160 rpm) for 24 h to obtain 6 kinds of non-acclimated bacterial suspensions (for standby);

[0201] Among them, the 6 strains are Bacillus sp. HY-1 in Example 1, Achromobacter sp. YH-1 in Example 1, Chitinophaga sp. MH-1 in Example 1, Methylorubrum sp. ZY-1 in Example 1, microbacterium sp in patent application No. 201910473499.0, and Sphingomonas sp. GY-1 in patent application No. 201910472687.1.

[0202] (2) Preparation of biochar: The dried water hyacinth biomass was crushed and placed in a ceramic crucible, compacted, and covered with a lid. The crucible was placed in a tube furnace and pyrolyzed at a temperature of 500°C for 4 hours under anoxic conditions (oxygen concentration less than 0.5%). The biochar was then washed with deionized water to remove surface ash and reduce its alkalinity, which is beneficial for the attachment and fixation of bacterial strains on its surface and protects bacterial viability. Finally, the biochar was dried, ground using a ball mill, and sieved through a 150-mesh screen to obtain water hyacinth biochar;

[0203] (3) Preparation of free bacterial agent: The six unacclimated bacterial suspensions in step (1) were mixed according to the following mass fractions: 45 parts of chitin bacteria, 25 parts of bacillus, 15 parts of achromobacter, 5 parts of methyl bacteria, 5 parts of sphingomonas, and 5 parts of microbacterium. The unacclimated free bacterial agent was obtained.

[0204] The viable bacterial counts of each microorganism in the unacclimated free bacterial agent were as follows: chitin bacteria 3.0×10 8 ~ 5.9×10 8 CFU / g, bacillus 2.2×10 8 ~ 3.4×10 8 CFU / g, achromobacter 1.2×10 8 ~ 2.0×10 8 CFU / g, methyl bacteria 3.6×10 7 ~ 8.1×10 7 CFU / g, sphingomonas 1.7×10 7 ~ 6.6×10 7 CFU / g, and microbacterium 1.8×10 7 ~ 4.5×10 7 CFU / g.

[0205] (4) Preparation of carbon-based bacterial agent: 1g of water hyacinth biochar from step (2) was placed in a high-sterilization pot and subjected to sterilization treatment at 121°C for 30 minutes. After cooling to room temperature, the sterilized water hyacinth biochar was obtained.

[0206] The sterilized water hyacinth biochar was thoroughly mixed with 30mL of free bacterial agent from step (3), and then placed in a constant-temperature shaking incubator (30°C, 160rpm) for 18-24 hours. The culture medium liquid was removed by filtration, and then washed with sterile water. The unacclimated water hyacinth carbon-based bacterial agent was obtained by vacuum freeze-drying.

[0207] The viable bacterial counts of each microorganism in the unacclimated water hyacinth carbon-based bacterial agent were as follows: chitin bacteria 4.3×10 8 ~ 9.8×10 8 CFU / g, bacillus 2.8×108 ~ 4.9 x 10 8 CFU / g, Achromobacter 2.2 x 10 8 ~ 3.1 x 10 8 CFU / g, Methylobacterium 7.1 x 10 7 ~ 1.3 x 10 8 CFU / g, Sphingomonas 6.6 x 10 7 ~ 1.0 x 10 8 CFU / g and Microbacterium 5.1 x 10 7 ~ 1.2 x 10 8 CFU / g.

[0208] Performance comparison test and results

[0209] 1. Method of performance comparison test:

[0210] A method for testing the repair effect of a material on composite contaminated soil in an electronic waste disassembly area, comprising the following steps:

[0211] (1) Collection and composition detection of the composite contaminated soil in the electronic waste disassembly area:

[0212] The contaminated soil (i.e. the composite contaminated soil in the electronic waste disassembly area) was collected from the contaminated land of an electronic waste disassembly site in Longtang Town, Qingyuan, Guangdong. The content of PCB 180 and the content of BDE-47 in the composite contaminated soil in the electronic waste disassembly area were determined by the gas chromatography-mass spectrometry method in Examples 7-9. The effective concentration of DTPA extractable Cd and the effective concentration of DTPA extractable Pb in the composite contaminated soil were determined by the standard of "GB / T 17141-1997 Soil Quality Determination of Lead and Cadmium by Graphite Furnace Atomic Absorption Spectrophotometry".

[0213] Analysis shows that the content of PCB 180 in the composite contaminated soil in the electronic waste disassembly area is 0.46 mg / kg, the content of BDE-47 is 0.12 mg / kg, the effective concentration of DTPA extractable Cd is 4.27 mg / kg, and the effective concentration of DTPA extractable Pb is 178 mg / kg.

[0214] (2) Use and application of the test material and efficacy evaluation:

[0215] 500g of the electronic waste disassembly area composite contaminated soil in step (1) was taken into a flowerpot, respectively, to obtain multiple groups of flowerpots containing the electronic waste disassembly area composite contaminated soil; 5g of the carbon-based microbial agent in Example 5 was uniformly covered on the surface of the composite contaminated soil according to the mass ratio of the electronic waste disassembly area composite contaminated soil to the experimental material being 100:1, and the microbial agent and the soil were fully stirred and mixed to obtain the carbon-based microbial agent experimental group; meanwhile, the same mass of water hyacinth biochar, the free bacterial microbial agent in Example 5, the unacclimated free bacterial microbial agent in Comparative Example 1, the unacclimated water hyacinth carbon-based bacterial microbial agent in Comparative Example 1, the wheat straw biochar-based microbial agent in Example 6, the corn straw biochar-based microbial agent and the sugarcane residue biochar-based microbial agent in Example 6 were added to the other flowerpots containing the electronic waste disassembly area composite contaminated soil as control groups, and the contaminated soil without adding any material was set as a blank control.

[0216] The experimental group and the control group were placed in a room temperature (20℃-25℃) for cultivation, and in the cultivation process, the humidity of the soil was maintained at 65%-75% of the field water holding rate; after 90d of cultivation, the residual amount of BDE-47, the residual amount of PCB180, the effective content of DTPA extractable Cd and the effective content of DTPA extractable Pd in the soil were determined.

[0217] It should be noted that the calculation methods of the BDE-47 removal rate, the PCB 180 removal rate, the Cd passivation rate and the Pd passivation rate in the present application are the same as those in other embodiments.

[0218] 2. Test results:

[0219] The actual composite contaminated soil containing BDE-47, PCB 180, lead and cadmium was repaired using the above-mentioned materials for 90d, and the treatment effect of different pollutants after 90d of repair was calculated. The repair effect of different materials on the electronic waste disassembly area composite contaminated soil is shown in Figure 8 .

[0220] As can be seen from Figure 8 , the degradation rates of BDE-47 and PCB 180 in the soil are 89.60% and 94.99% respectively, and the passivation rates of lead and cadmium in the soil are 76.39% and 90.37% respectively, and the calculation method is referred to Examples 7-9.

[0221] The actual compound contaminated soil containing BDE-47, PCB 180, lead and cadmium is repaired for 90 days by using different materials in the application. The pollutant concentration of the contaminated soil added with the bacterial agent is compared with that of the control group, and the treatment effect of different pollutants after 90 days of repair is calculated. According to the calculation result, the degradation rates of BDE-47 and PCB 180 in the soil treated by the uncultured free bacterial agent are 11.99% and 19.01% respectively, and the passivation rates of lead and cadmium in the soil are 16.64% and 19.47% respectively; the degradation rates of BDE-47 and PCB 180 in the soil treated by the uncultured water hyacinth carbon-based bacterial agent are 21.37% and 46.11% respectively, and the passivation rates of lead and cadmium in the soil are 61.37% and 43.28% respectively.

[0222] The degradation rates of BDE-47 and PCB 180 in the soil treated by the wheat straw biochar-based bacterial agent are 77.43% and 84.78% respectively, and the passivation rates of lead and cadmium in the soil are 70.52% and 73.35% respectively; the degradation rates of BDE-47 and PCB 180 in the soil treated by the corn straw biochar-based bacterial agent are 71.71% and 91.82% respectively, and the passivation rates of lead and cadmium in the soil are 58.63% and 76.48% respectively; the degradation rates of BDE-47 and PCB 180 in the soil treated by the sugarcane residue biochar-based bacterial agent are 82.15% and 93.10% respectively, and the passivation rates of lead and cadmium in the soil are 71.03% and 88.18% respectively.

[0223] It can be shown by comparing the known data that:

[0224] (1) The pollutant concentration of the contaminated soil added with the water hyacinth carbon-based bacterial agent is compared with that of the blank control group, the carbon-based bacterial agent can quickly and efficiently decompose and metabolize BDE-47 and PCB 180 in the actual soil, and at the same time, the heavy metals of lead and cadmium are passivated and inactivated, so the carbon-based bacterial agent in the application has good repair effect on the actual halogenated organic matter and heavy metal compound contaminated soil.

[0225] (2) Compared with the domesticated bacterial agent, the uncultured bacterial strain not only lacks tolerance to the compound pollutants, but also has weak interspecific interaction between the uncultured bacterial strains, resulting in poor repair effect of the uncultured carbon-based bacterial agent on the actual halogenated organic matter and heavy metal compound contaminated soil.

[0226] (3) The domesticated carbon-based bacterial agent has good degradation activity on BDE-47 and PCB 180 in the actual compound contaminated soil, and has good passivation performance on lead and cadmium, which can well realize the synchronous repair effect on the halogenated organic matter and heavy metal compound contaminated soil in the electronic waste disassembly site contaminated soil.

[0227] In conclusion, the biochar and the bacteria in the application can effectively adsorb, fix and passivate heavy metals in the soil, and degrade and convert halogenated organic pollutants. Meanwhile, the biochar can provide sufficient nutrient elements and attachment sites for the bacteria, and ensure the activity of the bacteria in the bacterial agent, so that the synergistic effect of the two improves the adaptability of the bacteria to the heavy metals and the halogenated organic pollutants, and further promotes the remediation effect of the bacteria on the halogenated organic pollutant-heavy metal composite contaminated soil.

[0228] The above embodiment is a preferred embodiment of the application, but the embodiments of the application are not limited to the above embodiment, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the application should be equivalent replacement methods, and are included in the protection scope of the application.

Claims

1. A method for preparing a carbon-based microbial inoculant for simultaneously degrading halogenated organic pollutants and passivating heavy metals, characterized in that: the halogenated organic pollutants and heavy metals are 2,2',4,4'-tetrabromodiphenyl ether and lead, or 2,2',3,4,4',5,5'-heptachlorodiphenyl and cadmium; and the method comprises the following steps: (1) activating strains: obtaining six kinds of bacterial suspensions by enriching and culturing chitin bacteria MH-1, bacillus HY-1, achromobacter YH-1, methyl bacillus ZY-1, sphingomonas GY-1 and microbacterium, wherein the preservation number of the chitin bacteria is GDMCC No: 62742, the preservation number of the bacillus is GDMCC No: 62740, the preservation number of the achromobacter is GDMCC No: 62741, the preservation number of the methyl bacillus is GDMCC No: 62743, the preservation number of the sphingomonas is GDMCC No: 60633, and the preservation number of the microbacterium is GDMCC No: 60634; (2) preparing biochar; and (3) preparing a free bacterial inoculant by mixing the bacterial suspensions in step (1). The acclimation in step (1) comprises: activating single strains to obtain bacterial suspensions, inoculating 5 mL of the bacterial suspensions into 100 mL of an initial inorganic salt liquid medium containing complex pollutants, wherein the concentration of 2,2',4,4'-tetrabromodiphenyl ether is 1 mg / L, the concentration of 2,2',3,4,4',5,5'-heptachlorodiphenyl is 1 mg / L, and the concentration of cadmium is 2 mg / L, and then culturing in a constant-temperature shaking incubator for 120 h to obtain a bacterial solution after the first acclimation. The medium for the second acclimation is the initial inorganic salt liquid medium containing complex pollutants, wherein the concentrations of 2,2',4,4'-tetrabromodiphenyl ether, 2,2',3,4,4',5,5'-heptachlorodiphenyl and cadmium are all increased by 1 mg / L, and the other components remain unchanged. The biochar is obtained by pyrolysis of plants, and the plants are selected from one or more of water hyacinth, wheat straw, corn straw and sugarcane residue. 3.A carbon-based microbial inoculant prepared by the method of claim 1 or 2. ​ (4) Preparation of the carbon-based microbial agent: the biochar in step (2) is sterilized, the sterilized biochar and the free bacterial agent in step (3) are mixed and cultured for 18-24 hours, the culture medium liquid is removed by filtration, then washed with sterile water, and vacuum freeze-dried to obtain the carbon-based microbial agent; the viable cell count of each microorganism in the carbon-based microbial agent is: chitin bacteria 4.5×10 8 ~2.0×10 9 CFU / g, Bacillus 2.0×10 8 ~7.0×10 8 CFU / g, achromobacter 1.0×10 8 ~4.5×10 9 CFU / g, methyl bacteria 1.5×10 7 ~2.5×10 8 CFU / g, sphingomonas 4.5×10 7 ~3.0×10 8 CFU / g, and microbacterium 7.5×10 7 ~3.5×10 8 CFU / g; ​ ​ ​ 2. The method of claim 1, wherein: ​ ​ 4. The use of the carbon-based microbial agent of claim 3 in simultaneous degradation of halogenated organic pollutants and passivation of heavy metals in soil, wherein the halogenated organic pollutants and heavy metals are 2,2',4,4'-tetrabromodiphenyl ether and lead, or 2,2',3,4,4',5,5'-heptachlorobiphenyl and cadmium.

5. A method of simultaneously degrading halogenated organic pollutants and passivating heavy metals, characterized in that, comprising the step of mixing the carbon-based microbial agent of claim 3 and a solid contaminated medium to obtain a mixture, i.e. capable of simultaneous degradation of halogenated organic pollutants and passivation of heavy metals; wherein the halogenated organic pollutants and heavy metals are 2,2',4,4'-tetrabromodiphenyl ether and lead, or 2,2',3,4,4',5,5'-heptachlorobiphenyl and cadmium.

6. The method of claim 5, wherein: The mass ratio of the carbon-based microbial agent and the solid contaminated medium is 0.8:100-20:100.

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