Biochar-loaded pseudomonas material capable of efficiently adsorbing H2S

Abstract

The invention provides a biochar-loaded pseudomonas material capable of efficiently adsorbing H2S, which is prepared by the following steps: mixing biochar-loaded pseudomonas and a resuspension obtained by centrifugally cleaning a pseudomonas culture medium with biochar, loading 3-4 mL of bacterial suspension per 10 g of biochar, and incubating at 30-37 DEG C for 20-24 hours to obtain the biochar-loaded pseudomonas material, or uniformly mixing 10 mL of resuspension with 10 g of biochar to obtain the biochar-loaded pseudomonas material capable of efficiently adsorbing H2S. And then loading on polyurethane foam together to obtain the biochar-loaded pseudomonas filler. The method has the beneficial effects that the biochar can fix H2S by utilizing own pore characteristics, the biochar can maintain the activity and stability of bacteria after being loaded with the pseudomonas DW-1, meanwhile, the pseudomonas DW-1 can assist in consuming and utilizing H2S gas for conversion, meanwhile, the humidity and adhesion of the biochar are maintained, the H2S removal time is shortened, and the adsorption removal performance of the biochar is enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of gas purification materials and relates to an adsorbent material for H2S. Background Art

[0002] During the construction of tunnels and mine shafts, in addition to common risk problems such as water gushing and cave - in, the treatment of dust and harmful gases is also an important issue that must be solved. Underground blasting, ore oxidation, spontaneous combustion, decay of pit wood, and operations in confined spaces such as deep foundation pits are prone to generating toxic and harmful gases. If these gases are not effectively controlled, they will pose a serious threat to the health and safety of construction workers. To ensure construction safety, the industry generally adopts time - limited operations and long - term ventilation methods, and safety supervisors detect the gas content in real - time to ensure that the oxygen content remains between 19.5% and 23.5%, and the concentrations of toxic gases, flammable gases, and dust strictly comply with national safety standards. However, although these measures can reduce risks to a certain extent, they also greatly limit the construction efficiency in high - risk construction areas such as deep foundation pits.

[0003] Hydrogen sulfide gas (H2S) is a common engineering geological problem in tunnel construction. H2S gas has extremely high toxicity and danger. When its concentration exceeds 50 ppm, construction workers may experience discomfort symptoms such as headache, dizziness, nausea, eye burns, and sore throat. If the hydrogen sulfide concentration reaches above 500 ppm, exposure for 30 minutes to 1 hour may lead to loss of consciousness and even pose a fatal risk. Therefore, controlling the generation and concentration of H2S gas is crucial for ensuring construction safety.

[0004] As a material with strong adsorption ability, biochar has been widely used in gas treatment in recent years. Biochar is a porous carbonaceous material prepared by pyrolysis of biomass and has adsorption characteristics similar to activated carbon. Its surface usually has abundant chemical active clusters and pore structures, which enables biochar to effectively adsorb harmful gases including H2S. Research shows that the chemical composition and surface properties of biochar are subject to factors such as raw material type, pyrolysis temperature, heating rate, and residence time. Common biomass raw materials include corn straw, bamboo, coconut shell, rice straw, and wheat straw. These raw materials are abundant and renewable, making them ideal choices for preparing high - efficiency biochar. Coupled with chemical modification with drugs, the adsorption performance can be effectively improved.

[0005] However, when biochar adsorbs harmful gases, its effect is greatly affected by environmental humidity. Existing research has shown that the adsorption capacity of biochar is most effective within a specific humidity range. Environments that are too dry or too wet will significantly reduce its adsorption effect. Therefore, how to maintain suitable humidity conditions to ensure the efficient use of biochar in tunnel construction has become a technical problem that needs to be solved urgently. In addition, the adsorption capacity of biochar will be affected by the saturation problem during long-term use, and it is necessary to consider how to improve its service life and regeneration ability.

[0006] In response to this problem, more and more research has begun to explore the combination of microbial technology and biochar to improve its ability to adsorb and transform harmful gases. Pseudomonas has been reported to have good desulfurization ability and can be applied to the treatment of sulfur-based malodors. Although Pseudomonas has great potential in gas transformation, due to its growth and reproduction requiring energy, the cost of using it alone is high and it is difficult to maintain its long-term activity, which limits its application effect and efficiency.

[0007] The synergistic treatment of harmful gases by biochar and functional strain loading is the current frontier direction of environmental pollution control. There are difficulties in regeneration after saturation and the risk of secondary release in single biochar adsorption, while free strains are vulnerable to environmental fluctuations, resulting in unstable degradation efficiency. By loading specific degrading bacteria on the porous carrier of biochar, an "adsorption-biological degradation" coupling system can be constructed: biochar rapidly enriches pollutants by virtue of its high specific surface area and surface functional groups, and provides attachment sites and slow-release nutrients for the strains; the functional bacteria achieve the targeted mineralization of pollutants through enzymatic reactions. This strategy significantly improves the treatment efficiency, and the pH buffering ability of biochar can maintain the activity of the microbial community, which is applicable to complex industrial waste gas scenarios. It can not only enhance the adsorption capacity of biochar, but also effectively extend its service life and reduce maintenance costs.

[0008] In summary, although existing ventilation and monitoring measures can ensure the safety of tunnel construction to a certain extent, more efficient technical means are still needed for the treatment of harmful gases such as hydrogen sulfide. The combination of biochar and Pseudomonas provides a novel and effective solution. Through measures such as optimizing humidity control, improving adsorption and transformation efficiency, and extending service life, this technology is expected to be widely applied in tunnel construction and deep foundation pit operations in the future, providing more powerful protection for construction safety. Summary of the Invention

[0009] The objective of the present invention is to propose a material of biochar loaded with Pseudomonas DW-1 for efficient adsorption of H2S. After the biochar is loaded with DW-1, the respiration of DW-1 itself can maintain the humidity of the material to a certain extent. At the same time, DW-1 can utilize and transform H2S to a certain extent, so as to remove H2S at a lower cost and higher efficiency for the poisoning situation of harmful gases in harmful spaces such as deep foundation pits, reduce the risks during the construction process, and ensure the personal safety of operators to a certain extent.

[0010] The technical solution of the present invention: A material of biochar loaded with Pseudomonas for efficient adsorption of H2S, where the biochar is loaded with Pseudomonas. A resuspension obtained by centrifuging and washing the Pseudomonas medium is mixed with the biochar. Every 10 g of biochar is loaded with 3 - 4 mL of the Pseudomonas resuspension, and incubated at 30 - 37 °C for 20 - 24 h to obtain the biochar loaded with Pseudomonas material. The Pseudomonas is Pseudomonas ( Pseudomonas sp . ) DW-1, which was deposited at the China Center for Type Culture Collection (CCTCC) on May 12, 2025, with the deposit number CCTCC NO: M 20251031.

[0011] Or Pseudomonas DW-1 is cultured to the logarithmic phase, 10 mL of the bacterial solution is evenly mixed with 10 g of biochar, and then they are jointly loaded onto polyurethane foam to obtain the biochar loaded with Pseudomonas DW-1 packing. The packing form is more convenient for transportation and placement.

[0012] Preferably, the biochar is modified bamboo powder, and the preparation method is as follows: Bamboo powder, K2FeO4, and KOH are added to deionized water according to a mass ratio of 3 - 3.5:2:2, magnetically stirred for 3 - 4 h, filtered through a 100-mesh filter, transferred to an oven at 80 - 85 °C for drying, heated in an inert atmosphere at a gas flow rate of 0.5 L / min and a pressure of 0.5 - 0.6 MPa to 650 - 700 °C at a heating rate of 8 - 10 °C / min and maintained for 2 - 2.5 h, then naturally cooled to room temperature, and then rinsed with pure water to make the pH neutral, and the product is dried at 80 °C to obtain the modified bamboo powder.

[0013] Obtaining of Pseudomonas DW-1: The microbial soil was isolated from a power tower foundation pit in Gansu Province. The sample was domesticated in medium MM to enrich potential H2S-assimilating bacteria, statically cultured at 30 °C, continuously domesticated for 4 weeks, and aerated with 200 mL of H2S once a week during this period. After domestication, LB medium was used for strain isolation and maintenance. After culturing at 30 °C for 1 day, single colonies were picked for strain identification.

[0014] Advantages of the present invention: After being loaded with biochar and Pseudomonas sp. DW-1, the activity and stability of the bacteria can be maintained, making the biochar material have a certain humidity. At the same time, Pseudomonas sp. DW-1 can assist in consuming and utilizing gases, converting H2S into elemental sulfur and H2SO4, without having an adverse impact on the original environment. Pseudomonas sp. DW-1 can also play a continuous moisturizing effect on the material through respiration, synergistically promoting the gas elimination effect, enhancing its performance, and shortening the time for removing H2S. It can efficiently adsorb and remove H2S in a closed space, and can efficiently remove H2S in closed environments such as deep foundation pits, mine tunnels, and sewer pipes.

[0015] Biomaterial preservation information: Pseudomonas sp. DW-1, classified and named as Pseudomonas sp . , on May 12, 2025, the preservation unit: China Center for Type Culture Collection (CCTCC), the preservation address: Wuhan, China; the preservation number: CCTCC NO: M 20251031. Description of the drawings

[0016] Figure 1 shows the surface morphology characterization of the material of the present invention, (a) SEM micrograph of bamboo powder biochar, (b) SEM micrograph of modified bamboo powder, (c) FTIR spectra of bamboo powder biochar before and after modification, (d) Raman spectra of bamboo powder biochar before and after modification.

[0017] Figure 2 is the EDS scan of modified bamboo powder before and after H2S adsorption, indicating successful modification with all elements present, and the S element in the material increasing after adsorption; Figure 3 is the phylogenetic tree of Pseudomonas sp. DW-1; Figure 4 is the colony morphology of Pseudomonas sp. DW-1 growing on an LB plate; Figure 5 is the N adsorption-desorption isotherm of bamboo powder before and after modification; Figure 6 is the comparison of the equilibrium adsorption and removal effects of H2S by the material of the present invention in Example 1 with bamboo powder, modified bamboo powder, and modified bamboo powder + Pseudomonas sp. DW-1; Figure 7 is the comparison of the flow adsorption and removal effects of H2S by the material of the present invention in Example 2 with modified bamboo powder and modified bamboo powder + Pseudomonas sp. Detailed implementation manners

[0018] Obtaining of Pseudomonas sp. DW-1: The microbial soil was isolated from the foundation pit of an electric tower in Gansu Province. The sample was domesticated in medium MM to enrich potential H2S-assimilating bacteria. The composition of medium MM was as follows: 4.5 g / L Na2HPO4·12H2O, 1.0 g / L KH2PO4, 1.5 g / L NH4Cl, 0.023 g / L CaCl2, 0.2 g / L MgCl2, and 1 mL of trace element stock solution, and the pH of the medium was 7.0. The composition of the trace element stock solution was: 1.0 g / L FeSO4·7H2O, 0.02 g / L CuSO4·5H2O, 0.014 g / L H3BO3, 0.10 g / L MnSO4·4H2O, 0.10 g / L ZnSO4·7H2O, 0.02 g / L Na2MnO4·2H2O, 0.02 g / L CoCl2·6H2O.

[0019] The culture was statically incubated at 30 °C for 4 consecutive weeks, and aerated with 200 mL of H2S once a week during this period. After domestication, LB medium was used for strain isolation and maintenance. The diluted culture was spread on LB plates and incubated for 1 day. Single colonies were picked after the strain grew to the logarithmic phase in LB medium. After washing 3 times with PBS, the assimilation efficiency of H2S was detected under the conditions of flow adsorption and mixed adsorption to obtain high-efficiency H2S-assimilating strains. The DNA of the strains was extracted and identified and classified by 16S rDNA sequencing. A phylogenetic tree was constructed using MegAlign software (MEGA version 4.0) based on the homologous 16S rDNA sequences. The results of strain identification were Pseudomonas sp . It was named Pseudomonas sp . DW-1 (Pseudomonas sp. DW-1).

[0020] Pseudomonas sp. DW-1, with the deposit number of CCTCC NO: M 20251031.

[0021] Sequencing of Pseudomonas Pseudomonas sp . DW-1 showed that its nucleotide sequence list was as shown in SEQ ID NO:1.

[0022] Example 1 Weigh 300 g, 200 g, and 200 g of bamboo powder, K2FeO4, and KOH respectively according to a mass ratio of 3:2:2. Add them to 4 L of deionized water, stir magnetically for 4 h, filter through a 100-mesh sieve, transfer to an oven at 80 °C for drying. Under a nitrogen atmosphere with a flow rate of 0.5 L / min and a pressure of 0.5 MPA, heat to 700 °C at a heating rate of 10 °C / min and hold for 2 h, then naturally cool to room temperature. Then rinse with pure water until the pH is neutral, and dry the sample at 80 °C to obtain modified bamboo powder biochar. The specific surface area of the modified bamboo powder biochar measured by the BET method is 432.7 m² / g. As Figure 1 shown, the pore size of the modified biochar (b) increases significantly. Figure (c) shows that after modification, there are stretching vibrations of C-C, C-O, C=O, and C-O-C bonds. In Figure (d), the two peaks I(D) (the former) and I(G) (the latter) correspond to the carbon defects in the lattice and the degree of carbonization of the material respectively. The I(D) / I(G) of bamboo powder is 0.85, and that of modified bamboo powder is 0.84, and there is no significant difference between the two. In summary, the modified bamboo powder biochar has better conditions for adsorbing H2S.

[0023] Culture Pseudomonas sp. DW-1 in LB liquid medium. The medium formula is LB medium (g / L, tryptone 10 g, yeast extract 5 g, sodium chloride 10 g). When the bacteria grow to the logarithmic phase, centrifuge and wash, then resuspend with PBS buffer. Incubate 4 mL of the resuspended solution with 10 g of modified bamboo powder at 37 °C for 24 h to obtain an adsorption material with biochar loaded with Pseudomonas sp.

[0024] Select a 25 ppm (tunnel construction alarm concentration) H2S standard gas. Use a 2 L sealed gas bag and introduce H2S gas into the gas bag at a speed of 0.5 L / min. In the CK group, only a four-in-one (H2S, CO, CH4, O2) gas detector from BW Company of Canada is placed; in the bamboo powder biochar group, 10 g of bamboo powder biochar and a gas detector are placed; in the modified bamboo powder biochar group, 10 g of modified bamboo powder biochar and a gas detector are placed; in the material group of the present invention, 10 g of the material of the present invention and a gas detector are placed. The results are as Figure 6 shown: Bamboo powder biochar has a good adsorption effect on H2S, and the gas concentration drops linearly. The modified bamboo powder has a faster effect and reduces the H2S concentration to 0 at 7 min. After incubating the modified bamboo powder with Pseudomonas sp. Pseudomonas sp . DW-1, the rising trend of the gas concentration is smoother and drops to 0 at about 5 min.

[0025] Example 2 Weigh 350 g of bamboo powder, 200 g of K2FeO4, and 200 g of KOH respectively, add them to 4 L of deionized water, stir magnetically for 3 h, filter through a 100-mesh sieve, transfer to an oven at 85 °C for drying. Under a nitrogen atmosphere at a flow rate of 0.5 L / min and a pressure of 0.6 MPa, heat it to 650 °C at a heating rate of 8 °C / min and hold for 2.5 h, then cool it naturally to room temperature, and then rinse with pure water to make the pH neutral. Dry the product at 80 °C to obtain modified bamboo powder biochar.

[0026] Culture Pseudomonas sp. DW-1 in LB liquid medium. The medium formula is LB medium. When the bacteria are cultured to the logarithmic phase, after centrifugation and washing, resuspend them with PBS buffer. Uniformly mix 10 mL of the bacterial solution with 10 g of biochar, and then load them onto polyurethane foam together to obtain biochar-loaded Pseudomonas sp. DW-1 filler.

[0027] Select a 25 ppm (tunnel construction alarm concentration) H2S standard gas, pass it through a 1 L odor sampling bottle at a rate of 0.5 L / min, and connect a four-in-one (H2S, CO, CH4, O2) gas detector of BW Company of Canada at the tail. The CK group is the blank group. The modified bamboo powder group contains 10 g of modified bamboo powder biochar inside, and the modified bamboo powder + Pseudomonas sp. DW-1 group contains 10 g of bamboo powder biochar-covered polyurethane foam adsorbed with Pseudomonas sp. DW-1 inside. The results are as Figure 7 shown. After passing 25 ppm of H2S through the modified bamboo powder group, the discharged gas decreased to 5 ppm, and the removal rate reached 80%. The discharged gas of the modified bamboo powder + Pseudomonas sp. DW-1 group decreased to 0, and the removal rate reached 100%.

Claims

1. A material of Pseudomonas loaded on biochar for efficiently adsorbing H2S, characterized in that: biochar Pseudomonas burden, the resuspension of Pseudomonas medium after centrifugation and washing is mixed with biochar. For every 10 g of biochar, 3 - 4 mL of Pseudomonas resuspension is loaded, and incubated at 30 - 37 °C for 20 - 24 h to obtain the biochar-loaded Pseudomonas material. The Pseudomonas is Pseudomonas Pseudomonas sp . DW-1, which was deposited at the China Center for Type Culture Collection on May 12, 2025, with the deposit number CCTCC NO: M 20251031.

2. A material of Pseudomonas aeruginosa loaded on biochar for efficiently adsorbing H2S, characterized in that: biochar Pseudomonas, cultivate Pseudomonas until the logarithmic phase, uniformly mix 10 mL of the bacterial solution with 10 g of biochar, and then load them together onto polyurethane foam to obtain biochar-loaded Pseudomonas filler. The Pseudomonas is Pseudomonas Pseudomonas sp . DW-1, which was deposited at the China Center for Type Culture Collection on May 12, 2025, with the deposit number CCTCC NO: M 20251031.

3. A material of Pseudomonas aeruginosa loaded on biochar for efficiently adsorbing H2S according to claim 1 or 2, characterized in that: The biochar is modified bamboo powder, and the preparation method is as follows: Mix bamboo powder, potassium ferrate, and potassium hydroxide in a mass ratio of 3 - 3.5:2:2, add deionized water, stir magnetically for 3 - 4 h, filter through a 100-mesh sieve, transfer to an oven at 80 - 85 °C for drying, under an inert atmosphere with a gas flow rate of 0.5 L / min and a pressure of 0.5 - 0.6 MPa, heat up to 650 - 700 °C at a heating rate of 8 - 10 °C / min and hold for 2 - 2.5 h, then naturally cool to room temperature, and then rinse with pure water to make the pH neutral, and dry the product at 80 °C to obtain the modified bamboo powder.

4. A material of Pseudomonas loaded on biochar for efficiently adsorbing H2S according to claim 1 or 2, characterized in that: Obtaining Pseudomonas DW-1: The microbial soil was isolated from a foundation pit of an electric tower in Gansu Province. The sample was domesticated in medium MM to enrich potential H2S-assimilating bacteria, cultured statically at 30 °C, continuously domesticated for 4 weeks, during which it was aerated with 200 mL of H2S once a week. After domestication, LB medium was used for strain isolation and maintenance. After culturing at 30 °C for 1 day, single colonies were picked for strain identification.

5. The material of Pseudomonas loaded on biochar for highly efficient H2S adsorption according to claim 4, characterized in that: The composition of medium MM is: 4.5 g / L Na2HPO4·12H2O, 1.0 g / L KH2PO4, 1.5 g / L NH4Cl, 0.023 g / L CaCl2, 0.2 g / L MgCl2, and 1 mL of trace element stock solution, and the pH of the medium is 7.0; the composition of the trace element stock solution is: 1.0 g / L FeSO4·7H2O, 0.02 g / L CuSO4·5H2O, 0.014 g / L H3BO3, 0.10 g / L MnSO4·4H2O, 0.10 g / L ZnSO4·7H2O, 0.02 g / L Na2MnO4·2H2O, 0.02 g / L CoCl2·6H2O.

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