Aromatic carbon-based microbial inoculum prepared by co-pyrolysis and method for rapidly removing high-concentration aryl halide pollutants by using aromatic carbon-based microbial inoculum

Abstract

The invention discloses an aromatic carbon-based microbial inoculum prepared by co-pyrolysis and a method for rapidly removing high-concentration aryl halide pollutants by using the aromatic carbon-based microbial inoculum. According to the method, the aromatic structure and the pore structure of the carbon material are optimized through co-pyrolysis, the carbon material is combined with the electroactive microbial agent to form the aromatic carbon-based microbial agent, and the aryl halide pollutants are rapidly removed through double paths of adsorption and reinforcement of extracellular electron transfer. The method for preparing the aromatic carbon-based microbial inoculum is simple and rapid, and meets the requirements of green sustainable development. Starting from fine structure regulation and control of the carbon material, double advantages of physical-chemical adsorption and microbial degradation are fused, and an efficient, environment-friendly and sustainable solution is provided for rapid removal of aryl halide pollutants.

Description

Technical Field

[0001] The present invention belongs to the field of environmental pollution control and remediation, and specifically relates to an aromatic carbon-based bacterial agent prepared by co-pyrolysis and a method for rapidly removing high-concentration halogenated aromatic hydrocarbon pollutants thereof. Background Art

[0002] Halogenated aromatic hydrocarbons are widely used and play a vital role in human production activities. However, these compounds are highly lipophilic and extremely chemically stable. Once they enter the environment, they will persist for a long time in solid environmental media such as soil and sediment, significantly increasing the difficulty of pollution control. Their migration and transformation in the natural environment are limited, and existing physical, chemical or biological remediation technologies often have difficulty in achieving efficient removal. Therefore, the development of efficient, green and sustainable halogenated aromatic hydrocarbon removal technologies has become a research focus in the field of environmental remediation.

[0003] Biomass-derived carbon materials are preferred for the efficient adsorption of halogenated aromatic hydrocarbons due to their well-developed pore structure, large specific surface area, and high chemical stability. However, such carbon materials may face problems such as adsorption saturation and difficulty in regeneration in complex environments. Furthermore, the adsorption effect of carbon materials primarily relies on physical and chemical interactions, making it difficult to completely degrade pollutants and posing a risk of secondary pollution. Therefore, they need to be combined with other treatment technologies to improve pollutant removal efficiency and achieve efficient and sustainable pollution control.

[0004] The carbon material-microorganism composite treatment strategy is an emerging pollution control technology that combines the dual advantages of physical-chemical adsorption and microbial degradation, providing an innovative solution for efficient pollutant removal and environmental remediation. Among them, electroactive bacteria, as a type of microorganism that can exchange electrons with external electron donors / acceptors through extracellular electron transfer, have unique degradation capabilities. However, the carbon material-electroactive bacteria composite treatment strategy currently still has a series of problems such as few active functional groups of carbon materials, poor conductivity, low electron transfer efficiency, and inhibition of microbial activity, making it difficult to meet the needs of efficient removal of organic pollutants in practical applications. Summary of the Invention

[0005] The present invention provides an aromatic carbon-based bacterial agent and a method for rapidly removing high-concentration halogenated aromatic hydrocarbon pollutants. By combining a carbon material with a rich aromatic structure and a developed pore structure with an electroactive bacterial agent to form an aromatic carbon-based bacterial agent, the aromatic carbon-based bacterial agent can not only rapidly adsorb halogenated aromatic hydrocarbon pollutants, but also strengthen the extracellular electron transfer process, significantly enhancing the biodegradation efficiency of pollutants, and solving the problem in the existing technology that only carbon materials for adsorption or microbial degradation are difficult to efficiently and rapidly remove halogenated aromatic hydrocarbon pollutants.

[0006] The first object of the present invention is to provide a method for preparing an aromatic carbon-based bacterial agent, which specifically comprises the following steps:

[0007] 1) Preparation of aromatic carbon materials: lignocellulosic biomass and organic waste biomass are mixed in a certain proportion, and then pyrolyzed under high temperature anaerobic conditions. After pyrolysis, the mixture is washed in an acidic solution, and then repeatedly washed with ultrapure water until the pH is neutral. The aromatic carbon material is obtained after drying.

[0008] 2) Preparation of an aromatic carbon-based bacterial agent: Under anaerobic sterile conditions, the aromatic carbon material of step 1) is added to a nutrient medium, and then an electroactive bacterial agent is inoculated and statically cultured to obtain an aromatic carbon-based bacterial agent; the electroactive bacterial agent is a culture of at least two of Shewanella oneidensis, Geobactersulfurreducens, and Desulfuromonas michiganensis.

[0009] Preferably, in step 1), the lignocellulosic biomass is selected from one or more of sawdust, coconut shells, and bamboo chips, and the organic waste biomass is selected from one or more of municipal sludge, livestock and poultry manure, and food waste.

[0010] Preferably, in step 1), the lignocellulosic biomass or organic waste biomass is ground and sieved to a particle size of 0.05 to 1 mm; the lignocellulosic biomass and the organic waste biomass are mixed in a mass ratio of (1 to 2): (1 to 2).

[0011] Preferably, in step 1), the specific step of pyrolysis is: under inert atmosphere conditions, heating the temperature to 600-800° C. at a slow heating rate of 5-10° C. / min and pyrolyzing for 0.5-1.5 h.

[0012] Preferably, in step 1), the intensity ratio of the D peak to the G peak of the Raman spectrum of the aromatic carbon material (I D / I G ) is less than 1.1.

[0013] Preferably, in step 2), the electroactive bacterial agent is a mixed culture of Shewanella oneidensis and Geobacter sulfurreducens, and its initial optical density OD 600 The concentration is 0.05-0.5, and the inoculation volume is 5-20% of the total reaction volume.

[0014] More preferably, the electroactive bacterial agent OD 600 is 0.1, by OD 6000.02 of Shewanella oneidensis culture with OD 600 0.02 of Geobacter sulfurreducens culture was mixed at a volume ratio of 1:4. Furthermore, the Shewanella oneidensis was Shewanella oneidensis MR-1, and the Geobacter was Geobacter sulfurreducens PCA.

[0015] Preferably, in step 2), the final concentration of the aromatic carbon material in the reaction system is 0.1 to 1 g / L; the nutrient medium in step 2) is a modified DSMZ medium, the formula of which is 0.60 g / L Na2HPO4, 0.10 g / L KCl, 1.50 g / LNH4Cl, 1.67 g / L CH3COONa, 0.8 g / L sodium fumarate, 1% (volume fraction) trace element solution, 1% (volume fraction) vitamin solution and 1% (volume fraction) selenite-tungstate solution, and the solvent is deionized water; the formula of the trace element solution is N(CH2COOH)3 1.5 g / L, MgSO4·7H2O 3.0 g / L, MnSO4·2H2O 0.5 g / L, NaCl 1.0 g / L, FeSO4·7H2O 0.10 g / L, CaCl2·2H2O 0.10g / L, CoCl20.10 g / L, ZnSO4

[0016] 0.10g / L, CuSO4·5H2O 0.01g / L, AlK(SO4)2·12H2O 0.01g / L, H3BO3 0.01g / L, Na2MoO4·2H2O 0.01g / L, NiCl2·6H2O 0.024g / L, Na2WO4·2H2O 0.025g / L; the vitamin solution formula is: vitamin H (biotin) 2mg / L, vitamin B9 (folic acid) 2mg / L, vitamin B6 10mg / L, ammonium sulfate hydrochloride 10mg / L, vitamin B2 (riboflavin) 1mg / L, niacin 1mg / L, DL-pantothenate calcium 1mg / L, vitamin B 12 0.1 mg / L, p-aminobenzoic acid 1 mg / L, lipoic acid 1 mg / L; the formula of the selenite-tungstate solution is: NaOH 5 g / L, Na2SeO3·5H2O0.003 g / L, Na2WO4·2H2O 0.004 g / L.

[0017] Preferably, in step 2), the static culture conditions are: temperature 20-35° C., and culture time 4-96 h.

[0018] The second object of the present invention is to provide an aromatic carbon-based bacterial agent prepared by the above preparation method.

[0019] The third object of the present invention is to provide the use of the aromatic carbon-based bacterial agent prepared by the above preparation method in removing halogenated aromatic hydrocarbon pollutants.

[0020] The fourth object of the present invention is to provide a method for removing halogenated aromatic hydrocarbon pollutants, and the specific steps are as follows: under anaerobic sterile conditions, the halogenated aromatic hydrocarbon pollutants are added to a fresh nutrient culture medium containing the above-mentioned aromatic carbon-based bacterial agent (refer to the above-mentioned nutrient culture medium, the only difference is that sodium fumarate is not required to be added), and the pollutants are cultured on a shaking table to quickly remove the pollutants.

[0021] Preferably, the dosage of the aromatic carbon-based bacterial agent is 5-20% of the total reaction volume, and the final concentration of halogenated aromatic hydrocarbon pollutants is 10-500 mg / L. The shaking incubation conditions are: a temperature of 20-35°C, a rotation speed of 100-200 rpm, and an incubation time of 24-72 hours. 93.2% of halogenated aromatic hydrocarbon pollutants can be removed within 72 hours, with a microbial degradation rate exceeding 60%.

[0022] The present invention uses a co-pyrolysis method to precisely and effectively modify the key active sites of carbon materials, regulating the pore structure and aromatic structure of the carbon materials. This not only significantly improves their adsorption capacity, but also increases the extracellular electron transfer rate of electroactive bacteria, strengthens the microbial degradation ability of pollutants, and enhances the synergistic effect between the carbon materials and electroactive bacteria. Compared with single microbial degradation or carbon material adsorption technology, the composite treatment strategy of carbon materials and electroactive bacteria is more efficient and thorough in removing halogenated aromatic hydrocarbon pollutants. It is suitable for responding to environmental emergencies, improving the processing capacity of pollution control systems, and promoting the effective remediation of polluted environments around industrial parks.

[0023] The present invention has the following beneficial effects:

[0024] (1) The preparation method of the aromatic carbon-based bacterial agent of the present invention is simple in process and easy to operate. The raw materials used to prepare the aromatic carbon material are derived from widely existing solid waste, which is low in cost and conforms to the concept of solid waste resource utilization and sustainable development.

[0025] (2) The carbon material prepared by co-pyrolysis in the present invention has a rich aromatic structure and a developed specific surface area, which gives it a strong adsorption capacity and improves the extracellular electron transfer rate of electroactive bacteria. The aromatic carbon-based bacterial agent finally prepared can achieve rapid removal of high-concentration halogenated aromatic hydrocarbon pollutants through the dual pathways of physical-chemical adsorption and microbial enhanced degradation.

[0026] (3) The present invention selects two different microorganisms as electroactive bacterial agents. Compared with a single bacterial species, the aromatic carbon-based bacterial agent prepared by mixing the two bacteria and combining them with aromatic carbon materials shows a significant synergistic effect.

[0027] In summary, this invention combines carbon material adsorption with microbial degradation, providing a highly efficient, environmentally friendly, and sustainable solution for the removal of halogenated aromatic hydrocarbons. This invention has significant application value in the field of environmental pollution control and will significantly promote innovation and advancement in environmental protection technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 These are scanning electron microscope images of the aromatic carbon material ACM prepared in step 1 of Example 1 (i.e., Comparative Example 8) and the sludge-based carbon material SCM prepared in step 1 of Comparative Example 3, wherein Figure A is the sludge-based carbon material SCM; Figure B is the aromatic carbon material ACM.

[0029] Figure 2 These are infrared spectra of the aromatic carbon material ACM prepared in step 1 of Example 1 (ie, Comparative Example 8) and the sludge-based carbon material SCM prepared in step 1 of Comparative Example 3.

[0030] Figure 3 These are Raman spectra of the aromatic carbon material ACM prepared in step 1 of Example 1 (ie, Comparative Example 8) and the sludge-based carbon material SCM prepared in step 1 of Comparative Example 3.

[0031] Figure 4 These are the specific surface area analysis results of the aromatic carbon material ACM prepared in step 1 of Example 1 (i.e., Comparative Example 8) and the sludge-based carbon material SCM prepared in step 1 of Comparative Example 3, where A is the N2 adsorption-desorption curve; B is the pore size distribution diagram.

[0032] Figure 5 These are the cyclic voltammograms of the aromatic carbon-based bacterial agent ACMB prepared in Example 1 and the sludge carbon-based bacterial agent SCMB prepared in Comparative Example 3.

[0033] Figure 6 This is the rapid removal effect of 2,5-dichloronitrobenzene by the carbon materials or bacterial agents prepared in Example 1, Comparative Examples 1-4 and Comparative Example 8.

[0034] Figure 7 The mass balance of 2,5-dichloronitrobenzene treated with the bacterial agents prepared in Example 1 and Comparative Examples 1-3.

[0035] Figure 8 This is the extracted ion chromatogram of the degradation products of 2,5-dichloronitrobenzene in Example 4.

[0036] Figure 9This is a comparison chart of the removal effects of the bacterial agents prepared in Example 1, Comparative Example 3, and Comparative Examples 5-7 on 2,5-dichloronitrobenzene. DETAILED DESCRIPTION

[0037] The following examples are provided to further illustrate the present invention, but are not intended to limit the present invention.

[0038] Example 1 Preparation of aromatic carbon-based bacterial agent

[0039] 1. Preparation of aromatic carbon materials

[0040] The sawdust was dried at room temperature for 24 hours. The residual municipal sludge was extracted from the secondary sedimentation tank of the sewage treatment plant, centrifuged and dried at 150°C for 96 hours. After grinding the two biomasses (sawdust and municipal sludge) separately in a ball mill, the particle size was controlled to about 0.12 mm using a 120-mesh sieve and a 100-mesh sieve. 2.5 g of sawdust and 2.5 g of municipal sludge were evenly mixed and placed in a 35 mL corundum boat. In a nitrogen atmosphere of 100 mL / min, the temperature was raised to 700°C at a rate of 7.5°C / min for pyrolysis and stayed for 1 hour. The pyrolysis product was soaked and washed three times with a 5 wt% HCl solution, and then washed with ultrapure water until the pH was neutral. After drying, the aromatic carbon material ACM was obtained.

[0041] 2. Preparation of electroactive bacterial agents

[0042] 2.1 Preparation of Shewanella oneidensis MR-1 bacterial suspension

[0043] The electroactive bacterium Shewanella oneidensis MR-1 (disclosed in the reference: Venkateswaran K., Moser DP, Dollhopf ME, Lies DP, Saffarini DA, Macgregor BJ, Ringelberg DB, White DC, Nishijima M., Sano H., Burghardt J., Stackebrandt E., Nealson KH, Polyphasic taxonomy of the genus Shewanella and description of Shewanella oneidensis sp. nov[J]. International Journal of Systematic Bacteriology, 1999, 49:705-724. The applicant also owns the strain and guarantees that it will be made available to the public from the date of filing this application) was cultured in a constant temperature shaker at 180 rpm and 30°C. After growing to the logarithmic phase (8 to 12 hours), the bacteria are centrifuged at 6500 rpm for 5 minutes and washed three times with sterile 50 mmol / L phosphate buffer that has been treated with N2 aeration and deoxygenation. Finally, Shewanella oneidensis MR-1 is resuspended in 50 mmol / L phosphate buffer to obtain a Shewanella oneidensis MR-1 bacterial suspension. The formula of the LB medium is as follows: 5.0 g / L yeast powder, 10.0 g / L peptone, 5.0 g / L NaCl, and the solvent is deionized water. After the LB medium is prepared, it is autoclaved at 121°C for 20 minutes. The formula of the phosphate buffer is as follows: 7.2 g / L Na2HPO4, 1.2 g / L KH2PO4, 1.0 g / L KCl and 40.0 g / L NaCl. After the phosphate buffer solution was prepared, it was deoxygenated by N2 aeration for 30 min and then sterilized by high pressure at 121 °C for 20 min.

[0044] 2.2 Preparation of Geobactersulfurreducens PCA bacterial suspension

[0045] In an anaerobic glove box at 30°C and with an oxygen content of less than 0.4%, Geobacter sulfurreducens PCA (this strain is disclosed in the reference: Caccavo F., Lonergan DJ, Lovley DR, Davis M., Stolz J.F., Mcinerney MJ, Geobacter sulfurreducens sp.nov., a hydrogen- and acetate-oxidizing dissimilatory metal-reducing microorganism [J]. Applied and Environmental Microbiology, 1994, 60(10): 3752-3759. This strain is also owned by the present applicant and the applicant guarantees that it will be made available to the public from the date of filing this application) was injected into a modified DSMZ medium that had been deoxygenated and sterilized for cultivation. After growing to the logarithmic phase (12 to 36 hours), the bacteria were centrifuged at 6500 rpm for 5 minutes and washed three times with sterile 50 mmol / L phosphate buffer that had been deoxygenated by N2 aeration. Finally, Geobactersulfurreducens PCA was resuspended in 50 mmol / L phosphate buffer to obtain a Geobactersulfurreducens PCA bacterial suspension. The modified DSMZ culture medium formula is: 0.60 g / L Na2HPO4, 0.10 g / L KCl, 1.50 g / L NH4Cl, 1.67 g / L CH3COONa, 0.8 g / L sodium fumarate, 1% (volume fraction) trace element solution (Table 1), 1% (volume fraction) vitamin solution (Table 2) and 1% (volume fraction) selenite-tungstate solution (Table 3), and the solvent is deionized water. After the modified DSMZ culture medium was boiled for 10 minutes to remove dissolved oxygen, its pH was adjusted to a range of 6.5 to 7.0 with 0.1 mol / L NaHCO3 solution. Subsequently, the culture medium was deoxygenated and aerated for 30 min using high-purity N2, sealed with a rubber stopper and an aluminum cap, and sterilized by autoclaving at 121 °C for 20 min.

[0046] 2.3 Preparation of electroactive bacterial agents

[0047] Optical density OD 600 0.02 Shewanella oneidensis MR-1 bacterial suspension with an optical density of OD 600 0.02% of Geobacter sulfurreducens PCA bacterial suspension was mixed in a volume ratio of 1:4 to obtain OD 600The initial electroactive bacterial inoculum was 0.1.

[0048] Table 1 Trace element solution formula:

[0049]

[0050]

[0051] Table 2 Vitamin solution formula:

[0052]

[0053]

[0054] Table 3 Selenite-tungstate solution formula:

[0055]

[0056] 3. Preparation of aromatic carbon-based bacterial agents

[0057] Use serum bottle as reaction device to prepare carbon-based bacterial agent, and change the optical density OD of step 2 to 600 A 0.1% electroactive bacterial inoculum was added to 50 mL of the modified DSMZ medium pre-loaded with carbon material (the aromatic carbon material (ACM) from step 1, with a final concentration of 0.5 g / L in the reaction system) at 10% of the total reaction volume. After 36 hours of static incubation in an anaerobic glove box at 30°C and an oxygen content below 0.4%, the aromatic carbon-based bacterial agent ACMB was obtained.

[0058] Comparative Example 1

[0059] Reference Example 1, except that, in step 2, the Shewanella oneidensis MR-1 bacterial suspension was not mixed with the Geobacter sulfurreducens PCA bacterial suspension, and only the optical density OD 600 A 0.1% suspension of Shewanella oneidensis MR-1 was used as the inoculum, and the other steps were the same as in Example 1 to prepare the ACMS bacterial agent.

[0060] Comparative Example 2

[0061] Reference Example 1, except that, in step 2, the Shewanella oneidensis MR-1 bacterial suspension was not mixed with the Geobacter sulfurreducens PCA bacterial suspension, and only the optical density OD was selected. 600A 0.1% suspension of Geobactersulfurreducens PCA was used as the inoculum, and the other steps were the same as in Example 1 to prepare the ACMG bacterial agent.

[0062] Comparative Example 3

[0063] Refer to Example 1, except that in step 1, the sawdust and municipal sludge are not mixed, and only municipal sludge is selected as the raw material for pyrolysis under the same conditions to obtain sludge-based carbon material SCM. The other steps are the same as in Example 1, and finally the sludge carbon-based bacterial agent SCMB is prepared.

[0064] Comparative Example 4

[0065] Refer to Example 1, except that, instead of performing steps 1 and 3, only performing step 2, the optical density OD 600 0.02 Shewanella oneidensis MR-1 bacterial suspension with an optical density of OD 600 0.02% of Geobactersulfurreducens PCA bacterial suspension was mixed in a volume ratio of 1:4 to prepare OD 600 It is an electroactive bacterial agent of 0.1.

[0066] Comparative Example 5

[0067] Refer to Example 1, except that, in step 1, there is no need to prepare the aromatic carbon material. Instead, commercially available powdered activated carbon (purchased from Sinopharm Chemical Reagent Company) is selected and mixed with the electroactive bacterial agent under the same conditions. The other steps are the same as in Example 1, and the activated carbon bacterial agent is finally prepared.

[0068] Comparative Example 6

[0069] Refer to Example 1, except that, in step 1, there is no need to prepare the aromatic carbon material. Instead, commercially available powdered multilayer graphene (purchased from Hongda Changjin Technology Co., Ltd.) is selected and mixed with the electroactive bacterial agent under the same conditions. The other steps are the same as in Example 1, and the graphene bacterial agent is finally prepared.

[0070] Comparative Example 7

[0071] Refer to Example 1, except that, in step 1, there is no need to prepare the aromatic carbon material. Instead, commercially available multi-walled powdered carbon nanotubes (purchased from Hongda Changjin Technology Co., Ltd.) are selected and mixed with the electroactive bacterial agent under the same conditions. The other steps are the same as in Example 1, and the carbon nanotube bacterial agent is finally prepared.

[0072] Comparative Example 8

[0073] Refer to Example 1, except that only step 1 is performed, and steps 2 and 3 are not performed, to prepare aromatic carbon material ACM.

[0074] Example 2 Surface morphology observation, surface functional group analysis, Raman spectroscopy analysis and specific surface area analysis of carbon materials

[0075] Take 0.5 g of the aromatic carbon material ACM (i.e., comparative example 8) prepared in step 1 of Example 1 and 0.5 g of the sludge-based carbon material SCM prepared in step 1 of comparative example 3, and dry them separately for surface morphology observation, surface functional group analysis, Raman spectroscopy analysis, and specific surface area analysis. The carbon material was fixed to a conductive table using conductive tape and sprayed with gold. The morphology was observed using a field emission scanning electron microscope at an accelerating voltage of 3 kV and a horizontal field width of 12.7 μm. Fourier transform infrared spectroscopy was used at 400-4000 cm -1 Wave number range is 4cm -1 The surface was scanned with a resolution of 1000 nm. Raman confocal microscopy was used to scan the surface at a laser excitation wavelength of 532 nm in a range of 500–2000 cm -1 The nitrogen adsorption-desorption curve and pore size distribution were measured using a specific surface area analyzer at 77K.

[0076] Figure 1 The SEM images of the two carbon materials are shown below. The sludge-based carbon material SCM is relatively soft and fragmented, with many irregular cracks visible. Figure 1 A). In comparison, the structure of aromatic carbon material ACM is relatively complete, in a curved state, with a large number of pore structures distributed on the surface ( Figure 1 B). Figure 2 The infrared spectra of two carbon materials are shown in the figure. As shown in the figure, the aromatic CH vibration (771cm -1 ) and aromatic skeleton bending vibration (553cm -1 ) showed a stronger absorption peak in the infrared spectrum, indicating further enrichment of the aromatic structure. Figure 3 The Raman spectra of two carbon materials are shown in the figure. As shown in the figure, the G peak representing the graphite crystal structure is enhanced in the aromatic carbon material ACM, and the ratio of its D peak to G peak is I D / I G <1.1, much lower than the I of sludge-based carbon materials SCM D / I G The ratio indicates the significant formation and enrichment of aromatic structures in aromatic carbon materials ACM. Figure 4 The N2 adsorption and desorption curves and pore size distribution diagrams of the two carbon materials are shown in Figure 2. The specific surface areas of the sludge-based carbon material SCM and the aromatic carbon material ACM are 21.32 m 2 / g and 65.27m 2 / g, and the pore volumes of SCM and ACM are 0.057 cm 3 / g and 0.069cm 3 / g. The above results demonstrate the effective synthesis of aromatic carbon materials ACM.

[0077] Example 3 Cyclic voltammetry curve test of bacterial agent

[0078] Cyclic voltammetry curves were tested on the aromatic carbon-based bacterial agent ACMB prepared in Example 1 and the sludge carbon-based bacterial agent SCMB prepared in Comparative Example 3 to analyze the extracellular electron transfer effect of the bacterial agents. The specific steps are as follows: a three-electrode reaction device was constructed using a glassy carbon electrode, a platinum electrode, and Ag / AgCl as the working electrode, counter electrode, and reference electrode, respectively; after nitrogen aeration treatment, 30mL of 100mM PBS buffer was added to a 50mL glass electrolytic cell as the electrolyte, and the amount of carbon-based bacterial agents (ACMB, SCMB) added was 0.1% of the total reaction system. Cyclic voltammetry curves were tested in an anaerobic chamber with a voltage range of -0.8V to 0.2V and a scan rate of 0.01V / s.

[0079] Figure 5 This is the cyclic voltammogram of two carbon-based bacterial agents. The current response degree of the aromatic carbon-based bacterial agent ACMB is much higher than that of the sludge carbon-based bacterial agent SCMB, indicating that the aromatic carbon-based bacterial agent ACMB has a rapid extracellular electron transfer process, which can enhance the degradation of halogenated aromatic hydrocarbon pollutants.

[0080] Example 4 Degradation of halogenated aromatic hydrocarbon pollutants

[0081] ACMB, ACMS, ACMG, SCMB, electroactive bacterial agents, activated carbon bacterial agents, graphene bacterial agents, carbon nanotube bacterial agents, ACM, and SCM (the sludge-based carbon material prepared in step 1 of Comparative Example 3) prepared in Example 1 and Comparative Examples 1-8 were added to the sterile, deoxygenated reaction medium at a volume fraction of 10%. 100 g / L of the halogenated aromatic hydrocarbon pollutant 2,5-dichloronitrobenzene was filtered and sterilized before being added to the reaction system to a final concentration of 200 mg / L. The reaction medium formulation and preparation method were similar to those of the modified DSMZ medium in Example 1, with the only difference being that sodium fumarate was not added. Cultures were performed in a shaking incubator at 30°C and 170 rpm.

[0082] At 0, 3, 6, 12, 24, 48, and 72 hours after the start of the reaction, 1 mL samples were withdrawn from the reaction system using a syringe. After filtration through a 0.22 μm nylon filter, the concentration of 2,5-dichloronitrobenzene in the samples was determined using ultra-high performance liquid chromatography (UPLC) with a C18 column. A gas chromatography-mass spectrometer was used to analyze the degradation products of 2,5-dichloronitrobenzene. The injection port and detector temperatures were set at 250°C and 300°C, respectively. The source was tuned in electron impact ionization mode, and chromatograms of 2,5-dichloronitrobenzene and its degradation products were extracted based on mass-to-charge ratio.

[0083] The removal effect of 2,5-dichloronitrobenzene is as follows: Figure 6 As shown in the figure, the aromatic carbon-based bacterial agent ACMB has the best removal effect on 2,5-dichloronitrobenzene, removing 93.2% of 2,5-dichloronitrobenzene within 72 hours. In comparison, the removal rates of 2,5-dichloronitrobenzene by ACM, ACMS and ACMG within 72 hours were 26.8%, 68.1% and 87.3%, respectively. The mass balance of 2,5-dichloronitrobenzene by aromatic carbon-based bacterial agents is shown in the figure. Figure 7 As shown, approximately 22.90-27.02% of 2,5-dichloronitrobenzene was adsorbed on the aromatic carbon material ACMB. As the reaction continued, ACMB promoted the gradual degradation of 2,5-dichloronitrobenzene. At 3 hours, the degradation rate was 19.6%, and at 72 hours, the degradation rate increased to 66.20%. The degradation product was 2,5-dichloroaniline ( Figure 8 Compared with the corresponding bacterial agents prepared from commercially available carbon materials such as activated carbon, graphene, and carbon nanotubes, the 72h removal rate of the aromatic carbon-based bacterial agent ACMB increased by 11.4-32.61% ( Figure 9 The above results demonstrate the superior performance of the aromatic carbon-based bacterial agent ACMB in the adsorption of 2,5-dichloronitrobenzene and the degradation of halogenated aromatic hydrocarbons.

Claims

1. A method for preparing an aromatic carbon-based bacterial agent, characterized in that: The following steps are involved: 1) mixing lignocellulosic biomass and organic waste biomass in a mass ratio of (1-2):(1-2), pyrolyzing them at 600-800° C. under anaerobic conditions, washing them in an acidic solution after pyrolysis, then washing them with water until the pH is neutral, and drying them to obtain an aromatic carbon material; 2) Under anaerobic sterile conditions, adding the aromatic carbon material of step 1) to a nutrient medium, then inoculating an electroactive bacterial agent, and culturing statically to obtain an aromatic carbon-based bacterial agent; the electroactive bacterial agent is a culture of at least two of Shewanella oneidensis, Geobactersulfurreducens, and Desulfuromonas michiganensis.

2. The method according to claim 1, characterized in that In step 1), the particle size of the lignocellulosic biomass or organic waste biomass is 0.05 to 1 mm; the lignocellulosic biomass is selected from one or more of sawdust, coconut shells, and bamboo chips, and the organic waste biomass is selected from one or more of municipal sludge, livestock and poultry manure, and food waste.

3. The method according to claim 1, characterized in that In step 1), the temperature is raised to 600-800° C. at a rate of 5-10° C. / min for pyrolysis for 0.5-1.5 h under anaerobic conditions.

4. The method according to claim 1, wherein In step 2), the electroactive bacterial agent is a mixed culture of Shewanella oneidensis and Geobacter sulfurreducens, and its initial optical density OD 600 The concentration of the HCl is 0.05-0.5, and it is inoculated at 5-20% of the total reaction volume.

5. The method according to claim 4, characterized in that The electroactive bacterial agent OD 600 is 0.1, which is determined by OD 600 0.02 of Shewanella oneidensis culture with OD 600 0.02% of Geobacter sulfurreducens culture was mixed at a volume ratio of 1:

4.

6. The method according to claim 1, characterized in that In step 2), the final concentration of the aromatic carbon material in the reaction system is 0.1-1 g / L; the static culture conditions are: temperature 20-35° C., and culture time 4-96 h.

7. The method according to claim 1, characterized in that In step 2), the nutrient medium formula is: 0.60g / L Na2HPO4, 0.10g / L KCl, 1.50g / LNH4Cl, 1.67g / L CH3COONa, 0.8g / L sodium fumarate, 1% volume fraction trace element solution, 1% volume fraction vitamin solution, 1% volume fraction selenite-tungstate solution, and the solvent is deionized water; the trace element solution formula is N(CH2COOH)31.5g / L, MgSO4·7H2O 3.0g / L, MnSO4·2H2O 0.5g / L, NaCl 1.0g / L, FeSO4·7H2O 0.10g / L, CaCl2·2H2O 0.10g / L, CoCl20.10 g / L, ZnSO4 0.10g / L, CuSO4·5H2O 0.01g / L, AlK(SO4)2·12H2O 0.01g / L, H3BO30.01 g / L, Na2MoO4·2H2O 0.01g / L, NiCl2·6H2O 0.024g / L, Na2WO4·2H2O0.025g / L; the vitamin solution formula is: vitamin H 2mg / L, vitamin B92 mg / L, vitamin B610mg / L, ammonium sulfate hydrochloride 10mg / L, vitamin B21 mg / L, niacin 1mg / L, DL-pantothenate calcium 1mg / L, vitamin B 12 0.1 mg / L, p-aminobenzoic acid 1 mg / L, lipoic acid 1 mg / L; the formula of the selenite-tungstate solution is: NaOH 5 g / L, Na2SeO3·5H2O 0.003 g / L, Na2WO4·2H2O 0.004 g / L.

8. The aromatic carbon-based bacterial agent prepared by the method according to any one of claims 1 to 7.

9. Use of the aromatic carbon-based bacterial agent according to claim 8 in removing halogenated aromatic hydrocarbon pollutants.

10. A method for removing halogenated aromatic hydrocarbon pollutants, characterized in that: Under anaerobic sterile conditions, halogenated aromatic hydrocarbon pollutants are added to a culture medium containing an aromatic carbon-based bacterial agent prepared by the method described in any one of claims 1 to 7, and cultured on a shaking table to remove the halogenated aromatic hydrocarbon pollutants.

Images