A bacterial agent material for water environment sediment remediation and a preparation method thereof

Abstract

The application relates to the field of water environment restoration, in particular to a bacterial agent material for water environment sediment restoration and a preparation method thereof. The bacterial agent material for water environment sediment restoration comprises 25-30 parts of a composite bacterial agent, 30-50 parts of a porous adsorption matrix, and microorganisms in the composite bacterial agent include at least three of pseudomonas, acinetobacter, lactobacillus and hydrogenophaga. According to the technical scheme, suitable microbial flora is selected, multiple groups of microorganisms are combined, direct organic cooperation is formed among the microorganisms, a large amount of reproduction is carried out in the initial stage, and the restoration efficiency of the sediment environment is effectively improved.

Description

Technical Field

[0001] This application relates to the field of water environment remediation, and more specifically, it relates to a microbial agent material for the remediation of bottom sediment in aquatic environments and its preparation method. Background Technology

[0002] "Black and odorous" water is an extremely complex biochemical phenomenon caused by the accumulation of large amounts of organic pollutants in rivers. The main causes of black and odorous water are twofold: the influx of exogenous pollutants and the release of endogenous pollutants. With increasingly stringent environmental regulations, exogenous pollution of water bodies has been curbed, while endogenous pollution has become the primary source. Therefore, the control and remediation of endogenous pollution in sediment has become a key factor in improving river water quality.

[0003] The organic matter in riverbed sediments is complex and diverse, and can be categorized into persistent, recalcitrant, and readily degradable organic matter based on its susceptibility to microbial degradation. Easily degradable organic matter first decomposes in the oxidized layer on the sediment surface, consuming a large amount of dissolved oxygen in the overlying water, undergoing aerobic mineralization. Subsequently, in the anoxic layer of the sediment, it is further degraded by nitrate nitrogen, sulfate, and Fe. 3+ It acts as an electron acceptor for the anaerobic mineralization of organic matter. The organic matter is mineralized as sulfate and Fe. 3+ Anaerobic mineralization, which acts as an electron acceptor, produces a large amount of blackening and odor-causing substances.

[0004] Regarding the aforementioned technologies, the inventors believe that while existing bioremediation technologies utilize the life activities of specific organisms (mainly microorganisms and plants) to degrade, adsorb, or transform pollutants in sediments, and are low-cost and do not cause secondary pollution, the slow speed of single-organism remediation makes it difficult to produce good remediation results in a short period of time. Summary of the Invention

[0005] To overcome the low remediation efficiency of existing bioremediation methods for aquatic sediments, this application provides a bacterial agent material for aquatic sediment remediation and its preparation method, employing the following technical solution: In the first aspect, this application provides a bacterial agent material for the remediation of sediment in aquatic environments, employing the following technical solution: A microbial agent material for the remediation of sediment in aquatic environments comprises the following substances in parts by weight: 25-30 parts of compound microbial agent; 30-50 parts of porous adsorption matrix; The microorganisms in the compound microbial agent include at least three of the following: Pseudomonas, Trichomonas vaginalis, Taurella, Lactobacillus, and hydrogen-eating bacteria.

[0006] By adopting the above technical solution, the technical solution of this application selects suitable microbial communities, and the multiple groups of microorganisms in the composite configuration can directly form an organic combination with each other, and reproduce in large quantities in the initial stage, thereby effectively improving the remediation efficiency of the bottom sediment environment.

[0007] The compound microbial agent includes *Pseudomonas schlegelii*, *Trichomonas testis*, *Taurella multocida*, *Lactobacillus fermentum*, *Lactobacillus acidophilus*, and hydrogen-eating bacteria.

[0008] Furthermore, the porous adsorption matrix is ​​a photocatalytic porous adsorption matrix doped with photocatalytic materials.

[0009] By adopting the above technical solution, the technical solution of this application selects porous photocatalytic materials as the main carrier. On the one hand, photocatalytic materials can effectively photocatalytically degrade and adsorb heavy metals and other materials in the water environment that are detrimental to microbial agents, thereby improving the survival status of microorganisms in the environment. On the other hand, porous photocatalytic materials have strong adsorption capacity, large specific surface area, and good water permeability. In actual use, they can first serve as a carrier for microbial agents, and then as an effective carrier for adsorbing heavy metals and ammonia nitrogen in bottom sediment, thereby further improving the efficiency and quality of microbial remediation of the water environment.

[0010] Furthermore, the photocatalytic porous adsorption matrix is ​​a MOF-zinc oxide porous material.

[0011] Furthermore, the MOF-zinc oxide porous material is prepared using the following method: Zinc nitrate, DMF, and 2-methylimidazole were mixed and subjected to hydrothermal reaction. The mixture was then heated to allow the reaction to proceed. The reactants were collected, mixed with N,N-dimethylformamide, washed, centrifuged, and dried to obtain the dried product. The dried material is placed in a muffle furnace and calcined at high temperature to prepare the MOF-zinc oxide porous material.

[0012] By adopting the above technical solution, the technical solution of this application further optimizes the structure and composition of the photocatalytic porous adsorption matrix. The combination of metal-organic framework and zinc oxide material is selected. The surface of MOF material has many surface functional groups and its specific surface area is large, which can further improve the adsorption performance of the porous adsorption matrix material. On this basis, it provides higher efficiency for photocatalytic degradation.

[0013] Based on this, this application selects zinc oxide as the main material for photocatalysis. Zinc oxide not only has good photocatalytic degradation efficiency, but also has low production cost and does not produce secondary pollution. Its performance and structure are also relatively stable, which can further improve the remediation efficiency while reducing the remediation cost.

[0014] Furthermore, the photocatalytic porous adsorption matrix is ​​a MOF-zinc oxide-doped organic photocatalytic porous material.

[0015] Furthermore, the MOF-zinc oxide-doped organic photocatalytic porous material is prepared using the following method: MOF-zinc oxide porous material was placed in a muffle furnace and calcined at high temperature. It was then mixed with dicyandiamide and placed in deionized water. After rotary evaporation and drying, the dried particles were collected and placed in a tube furnace for high-temperature calcination to prepare MOF-zinc oxide-doped organic photocatalytic porous material.

[0016] By adopting the above technical solution, the technical solution of this application further combines organic photocatalytic materials with inorganic photocatalytic materials in an effective manner. Since the organic photocatalytic material prepared in this application is graphitic carbon nitride, it has good light response. The porous adsorption matrix prepared by this solution has a large specific surface area, providing more possibilities for photocatalytic active sites. While effectively improving catalytic efficiency, it further improves the effect of water environment remediation.

[0017] Secondly, this application provides a method for preparing a microbial agent material for the remediation of sediment in aquatic environments, comprising the following preparation steps: The porous adsorption matrix and bacterial seed solution are placed in a shaker and cultured by shaking. Chitosan solution is then added, mixed, and dripped into NaOH solution. After solidification, the mixture is filtered, washed, and collected to obtain gel microspheres, thus preparing the bacterial agent material for the remediation of sediment in aquatic environments.

[0018] By adopting the above technical solution, the preparation process of the bacterial agent material for the remediation of sediment in the water environment is further optimized. The present application uses chitosan to encapsulate and coat the porous adsorption matrix and the bacterial strain. On the one hand, this increases the loading of the bacterial strain in the porous adsorption matrix. On the other hand, chitosan can isolate the binding between the photocatalytic material and the bacterial agent, thereby preventing the photocatalytic material from damaging the bacteria in the bacterial agent material.

[0019] In summary, this application includes at least one of the following beneficial technical effects: First, the technical solution of this application selects porous photocatalytic materials as the main carrier. On the one hand, photocatalytic materials can effectively photocatalytically degrade and adsorb heavy metals and other materials in the water environment that are detrimental to microbial agents, thereby improving the survival status of microorganisms in the environment. On the other hand, porous photocatalytic materials have strong adsorption capacity, large specific surface area, and good water permeability. In actual use, they can first serve as a carrier for microbial agents, and then as an effective carrier for adsorbing heavy metals and ammonia nitrogen in bottom sediment, thereby further improving the efficiency and quality of microbial remediation of the water environment.

[0020] Secondly, the technical solution of this application further optimizes the structure and composition of the photocatalytic porous adsorption matrix by using a combination of metal-organic framework and zinc oxide material. The surface of the MOF material has numerous surface functional groups and a large specific surface area, which can further improve the adsorption performance of the porous adsorption matrix material. On this basis, it provides higher efficiency for photocatalytic degradation.

[0021] Based on this, this application selects zinc oxide as the main material for photocatalysis. Zinc oxide not only has good photocatalytic degradation efficiency, but also has low production cost and does not produce secondary pollution. Its performance and structure are also relatively stable, which can further improve the remediation efficiency while reducing the remediation cost.

[0022] Third, the technical solution of this application further combines organic photocatalytic materials with inorganic photocatalytic materials. Since the organic photocatalytic material prepared in this application is graphitic carbon nitride, it has good light response. The porous adsorption matrix prepared by this solution has a large specific surface area, providing more photocatalytic active sites. While effectively improving catalytic efficiency, it further improves the effect of water environment remediation. Detailed Implementation

[0023] The present application will be further described in detail below with reference to the embodiments.

[0024] Preparation Example 1 MOF-zinc oxide porous material 1 Take 0.5 kg of zinc nitrate, 50 kg of DMF and 0.15 kg of 2-methylimidazole, stir and mix them, and then carry out the hydrothermal reaction at 140℃, followed by heating to continue the reaction. The reactants were collected, mixed with 6 kg of N,N-dimethylformamide, washed, centrifuged, and dried at 60 °C to obtain the dried product. The dried material is placed in a muffle furnace and calcined at 600°C to obtain the MOF-zinc oxide porous material.

[0025] Preparation Example 2 MOF-zinc oxide porous material 2 Take 0.1 kg of zinc nitrate, 65 kg of DMF and 0.2 kg of 2-methylimidazole, stir and mix them, and then carry out the hydrothermal reaction at 145℃, followed by heating to continue the reaction. The reactants were collected, mixed with 7 kg of N,N-dimethylformamide, washed, centrifuged, and dried at 65 °C to obtain the dried product. The dried material is placed in a muffle furnace and calcined at 625°C to obtain the MOF-zinc oxide porous material 2.

[0026] Preparation Example 3 MOF-zinc oxide porous material 3 Take 1.5 kg of zinc nitrate, 80 kg of DMF and 0.25 kg of 2-methylimidazole, stir and mix them, and then carry out the hydrothermal reaction at 150 °C, followed by heating to continue the reaction. The reactants were collected, mixed with 8 kg of N,N-dimethylformamide, washed, centrifuged, and dried at 70 °C to obtain the dried product. The dried material is placed in a muffle furnace and calcined at 650°C to obtain the MOF-zinc oxide porous material 3.

[0027] Preparation Example 4 MOF-zinc oxide-doped organic photocatalytic porous materials 1 MOF-zinc oxide porous material 1 was placed in a muffle furnace and calcined at 400℃. 200g of calcined particles were mixed with 3kg of dicyandiamide and placed in 15kg of deionized water. After rotary evaporation and drying, the dried particles were collected and placed in a tube furnace and calcined at 550℃ to prepare MOF-zinc oxide-doped organic photocatalytic porous material 1.

[0028] Preparation Example 5 MOF-zinc oxide-doped organic photocatalytic porous materials 2 MOF-zinc oxide porous material 1 was placed in a muffle furnace and calcined at 425℃. 350g of calcined particles were mixed with 5kg of dicyandiamide and placed in 15kg of deionized water. After rotary evaporation and drying, the dried particles were collected and placed in a tube furnace and calcined at 575℃ to prepare MOF-zinc oxide-doped organic photocatalytic porous material 2.

[0029] Preparation Example 6 MOF-zinc oxide-doped organic photocatalytic porous materials 3 MOF-zinc oxide porous material 1 was placed in a muffle furnace and calcined at 450℃. 500g of calcined particles were mixed with 8kg of dicyandiamide and placed in 15kg of deionized water. After rotary evaporation and drying, the dried particles were collected and placed in a tube furnace and calcined at 600℃ to prepare MOF-zinc oxide-doped organic photocatalytic porous material 3.

[0030] Preparation Example 7 Compound bacterial agent: 5 kg of Pseudomonas schrenckii, 5 kg of Trichomonas testis, 5 kg of Tauella, 2 kg of Lactobacillus fermentum, 3 kg of Lactobacillus acidophilus and 5 kg of hydrogen-eating bacteria are mixed with 225-270 kg of water to prepare bacterial seed solution.

[0031] Example 1 A method for preparing a microbial agent material for aquatic sediment remediation: 30 kg of MOF-zinc oxide porous material 1 and 25 kg of microbial seed solution are placed in a shaker and shaken at 37°C and 180 rpm for 24 h. Then, 37 kg of 3% chitosan solution is added, mixed, and then dropped into 0.2 kg of 0.5 mol / L NaOH solution. After standing and solidifying for 12 h, the mixture is filtered, washed, and collected to obtain gel microspheres, thus preparing the microbial agent material for aquatic sediment remediation.

[0032] Example 2 A method for preparing a microbial agent material for aquatic sediment remediation: 40 kg of MOF-zinc oxide porous material 1 and 27 kg of microbial seed solution are placed in a shaker and shaken at 37℃ and 180 rpm for 24 h. Then, 42 kg of 3% chitosan solution is added, mixed, and then dropped into 0.35 kg of 0.5 mol / L NaOH solution. After standing and solidifying for 12 h, the mixture is filtered, washed, and collected to obtain gel microspheres, thus preparing the microbial agent material for aquatic sediment remediation.

[0033] Example 3 A method for preparing a microbial agent material for aquatic sediment remediation: Take 50 kg of MOF-zinc oxide porous material 1 and 30 kg of microbial seed solution and place them in a shaker. Shake at 37°C and 180 rpm for 24 h. Then add 46 kg of 3% chitosan solution and mix. Drop the mixture into 0.5 kg of 0.5 mol / L NaOH solution. Let it stand and solidify for 12 h, then filter, wash and collect the gel microspheres to obtain the microbial agent material for aquatic sediment remediation.

[0034] Example 4 A method for preparing a microbial agent material for aquatic sediment remediation: 30 kg of MOF-zinc oxide porous material 2 and 25 kg of microbial seed solution are placed in a shaker and shaken at 37°C and 180 rpm for 24 h. Then, 37 kg of 3% chitosan solution is added, mixed, and then dropped into 0.2 kg of 0.5 mol / L NaOH solution. After standing and solidifying for 12 h, the mixture is filtered, washed, and collected to obtain gel microspheres, thus preparing the microbial agent material for aquatic sediment remediation.

[0035] Example 5 A method for preparing a microbial agent material for aquatic sediment remediation: 30 kg of MOF-zinc oxide porous material 3 and 25 kg of microbial seed solution are placed in a shaker and shaken at 37°C and 180 rpm for 24 h. Then, 37 kg of 3% chitosan solution is added, mixed, and then dropped into 0.2 kg of 0.5 mol / L NaOH solution. After standing and solidifying for 12 h, the mixture is filtered, washed, and collected to obtain gel microspheres, thus preparing the microbial agent material for aquatic sediment remediation.

[0036] Example 6 A method for preparing a microbial agent material for aquatic sediment remediation: 30 kg of MOF-zinc oxide-doped organic photocatalytic porous material 1 and 25 kg of microbial seed solution are placed in a shaker and shaken for 24 h at 37℃ and 180 rpm. Then, 37 kg of 3% chitosan solution is added, mixed, and then dropped into 0.2 kg of 0.5 mol / L NaOH solution. After standing and solidifying for 12 h, the mixture is filtered, washed, and collected to obtain gel microspheres, thus preparing the microbial agent material for aquatic sediment remediation.

[0037] Example 7 A method for preparing a microbial agent material for aquatic sediment remediation: 30 kg of MOF-zinc oxide-doped organic photocatalytic porous material 2 and 25 kg of microbial seed solution are placed in a shaker and shaken for 24 h at 37℃ and 180 rpm. Then, 37 kg of 3% chitosan solution is added, mixed, and then dropped into 0.2 kg of 0.5 mol / L NaOH solution. After standing and solidifying for 12 h, the mixture is filtered, washed, and collected to obtain gel microspheres, thus preparing the microbial agent material for aquatic sediment remediation.

[0038] Example 8 A method for preparing a microbial agent material for aquatic sediment remediation: 30 kg of MOF-zinc oxide-doped organic photocatalytic porous material 3 and 25 kg of microbial seed solution are placed in a shaker and shaken at 37°C and 180 rpm for 24 h. Then, 37 kg of 3% chitosan solution is added, mixed, and then dropped into 0.2 kg of 0.5 mol / L NaOH solution. After standing and solidifying for 12 h, the mixture is filtered, washed, and collected to obtain gel microspheres, thus preparing the microbial agent material for aquatic sediment remediation.

[0039] Comparative Example 1 Compared with Example 1, this comparative example only includes Lactobacillus acidophilus inoculum.

[0040] Performance testing The performance of the aquatic sediment remediation microbial agents prepared in Examples 1-8 and Comparative Example 1 was tested. The actual river water and sediment used in the experiment were both taken from a secondary river in a city in Jiangsu Province. The river water was collected using a water sampler and transported back to the laboratory for later use or transported to the pilot reactor site by water tanker. The sediment was taken from the surface layer of the sediment in the secondary river, collected using a sediment sampler, placed in sterile sampling bottles, and transported back to the laboratory in a 4°C refrigerator for later use.

[0041] The experimental setup simulated a river channel, with reactor dimensions of 1.8m × 1.0m × 0.5m. A 15cm high baffle was installed at the bottom to prevent bottom sediment from being carried away after water circulation began. The reactor was equipped with a hydraulic circulation system and an aeration system. An inlet was located at the bottom, and two outlets were located at 0.25m and 1.25m on the other side. Energy dissipation plates were installed above the inlet and in front of the outlets to stabilize the water flow. A laminar flow guide pipe was also installed on one side of the inlet to stabilize the flow pattern. A micro-aeration device was located in the center of the reactor. Aeration branch pipes and their connected aeration membrane fibers aerated the river water in the water. The aeration branch pipes were connected to an air pump and a rotor flowmeter to control the aeration rate. During the experiment, the device produced bubbles with a diameter of 2–5mm. Three water intakes were located at 0.35m, 0.55m, and 0.75m from top to bottom at the front of the reactor. The front of the reactor was made of transparent tempered glass for observing experimental phenomena, while the sides and bottom were made of stainless steel. The dosage of the bacterial agent used for sediment remediation in aquatic environments was 60 g / L. Sediment parameters were measured at 48 h and 96 h.

[0042] Initial physicochemical properties of sediment: Sediment COD concentration: 18 g / kg.

[0043] The performance test results are shown in the table below: Table 1 Performance Testing

[0044] As can be seen from the technical solutions and performance test tables of Examples 1-5 and Comparative Example 1, the technical solution of this application optimizes the structure and composition of the photocatalytic porous adsorption matrix, selects the combination of metal-organic framework and zinc oxide material, and the MOF material has many surface functional groups and a large specific surface area, which can further improve the adsorption performance of the porous adsorption matrix material. On this basis, it provides higher efficiency for photocatalytic degradation.

[0045] Based on this, this application selects zinc oxide as the main material for photocatalysis. Zinc oxide not only has good photocatalytic degradation efficiency, but also has low production cost and does not produce secondary pollution. Its performance and structure are also relatively stable, which can further improve the remediation efficiency while reducing the remediation cost.

[0046] Meanwhile, considering the technical solutions of Examples 6-8 and Example 1 of this application, it can be seen that the technical solution of this application further combines organic photocatalytic materials with inorganic photocatalytic materials in an effective manner. Since the organic photocatalytic material prepared in this application is graphitic carbon nitride, it has good light response. The porous adsorption matrix prepared by this scheme has a large specific surface area, providing more possibilities for photocatalytic active sites. While effectively improving catalytic efficiency, it further improves the effect of water environment remediation.

[0047] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A microbial agent material for the remediation of sediment in aquatic environments, characterized in that, Includes the following substances by weight: 25-30 parts of compound microbial agent; 30-50 parts of porous adsorption matrix; The microorganisms in the compound microbial agent include Pseudomonas, Trichomonas vaginalis, Taurella multocida, Lactobacillus, and hydrogen-eating bacteria. The porous adsorption matrix is ​​a photocatalytic porous adsorption matrix doped with photocatalytic materials; The photocatalytic porous adsorption matrix is ​​a MOF-zinc oxide porous material; The MOF-zinc oxide porous material is prepared using the following method: Zinc nitrate, DMF, and 2-methylimidazole were mixed and subjected to hydrothermal reaction. The mixture was then heated to allow the reaction to proceed. The reactants were collected, mixed with N,N-dimethylformamide, washed, centrifuged, and dried to obtain the dried product. The dried material was placed in a muffle furnace and calcined at high temperature to obtain the MOF-zinc oxide porous material. The bacterial agent material for aquatic sediment remediation is prepared using the following method: The porous adsorption matrix and the bacterial seed solution were placed in a shaker and cultured by shaking. Chitosan solution was added, mixed, and then dripped into NaOH solution. After solidification, the mixture was filtered, washed, and collected to obtain gel microspheres, thus preparing the bacterial agent material for the remediation of sediment in the aquatic environment.

2. The bacterial agent material for aquatic sediment remediation according to claim 1, characterized in that, The compound microbial agent includes *Pseudomonas schlegelii*, *Trichomonas testis*, *Taurella multocida*, *Lactobacillus fermentum*, *Lactobacillus acidophilus*, and hydrogen-eating bacteria.

3. The bacterial agent material for aquatic sediment remediation according to claim 1, characterized in that, The photocatalytic porous adsorption matrix is ​​a MOF-zinc oxide-doped organic photocatalytic porous material.

4. The bacterial agent material for aquatic sediment remediation according to claim 3, characterized in that, The MOF-zinc oxide-doped organic photocatalytic porous material was prepared using the following method: MOF-zinc oxide porous material was placed in a muffle furnace and calcined at high temperature. It was then mixed with dicyandiamide and placed in deionized water. After rotary evaporation and drying, the dried particles were collected and placed in a tube furnace for high-temperature calcination to prepare MOF-zinc oxide-doped organic photocatalytic porous material.

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