Composite microbial agent for sewage treatment and preparation method thereof
By preparing high-density biochar and grafting amino groups onto its surface, the problems of microbial floating and loss and low biochar density were solved, resulting in more efficient wastewater treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 山东永卫生物科技有限公司
- Filing Date
- 2026-05-09
- Publication Date
- 2026-06-05
AI Technical Summary
Existing microorganisms are prone to floating and loss during wastewater treatment, exhibiting poor stability. Biochar density also easily migrates with the water, affecting treatment efficiency.
High-density biochar was prepared using clay and biomass materials. After modification with tetraethoxysilane, it was reacted with ferric chloride hexahydrate to form iron-modified high-density biochar. Amino groups were then grafted onto the surface to prepare a composite microbial agent.
It improves the solidification effect and loading capacity of microorganisms, enhances the removal capacity of nitrogen and phosphorus, improves the surface roughness and pore structure of biochar, and improves the efficiency of wastewater treatment.
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Figure CN122146685A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a composite microbial agent for wastewater treatment and its preparation method. Background Technology
[0002] With rapid economic development and a dramatic increase in population, large amounts of industrial, agricultural, and domestic wastewater, carrying various organic matter and nutrients such as nitrogen and phosphorus, are discharged into rivers, lakes, and seas, causing water quality to deteriorate and endangering human health. Since nitrogen and phosphorus are the main nutrients leading to eutrophication, algae grow rapidly in the water. The large-scale growth of algae consumes oxygen in the water, causing fish and plankton to die from oxygen deprivation. Their decomposing bodies further pollute the water. Therefore, controlling the nitrogen and phosphorus content in water bodies is fundamental to treating eutrophic wastewater.
[0003] Currently, among wastewater denitrification and phosphorus removal technologies, microbial denitrification and phosphorus remediation technology is the most widely used method due to its good treatment effect. However, microorganisms are generally in a floating state during wastewater treatment, making them not only prone to loss but also highly sensitive to changes in the aquatic environment and exhibiting poor stability. Microbial immobilization technology is considered a potentially effective method, as it can maintain high microbial activity.
[0004] Biochar has attracted increasing attention due to its cost-effectiveness and physicochemical properties. Its large effective surface area, high porosity, and abundant functional groups provide valuable habitats for microorganisms. However, because biochar is lighter than water, it easily migrates with water, resulting in poor water treatment performance. Summary of the Invention
[0005] The purpose of this invention is to provide a composite microbial agent for wastewater treatment and its preparation method, so as to solve the above-mentioned technical problems.
[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows: A method for preparing a compound microbial agent for wastewater treatment includes the following steps: S1. Using clay and biomass materials as composite biomass materials, the composite biomass materials are mixed with an ethanol aqueous solution, ultrasonically treated, and then tetraethoxysilane is added to adjust the pH to 3-5. After stirring for 2 hours, the mixture is heated at 80-85℃ for 12-15 minutes to obtain a paste. The paste is then subjected to pyrolysis once and acid-modified to obtain high-density biochar materials. The biomass material comprises, by weight, the following components: 1-2 parts apricot shells, 1-2 parts walnut shells, 2-3 parts sawdust, and 2-3 parts ginkgo leaf powder; S2. Dissolve ferric chloride hexahydrate in water, add high-density biochar material, and stir ultrasonically to obtain a suspension. Adjust the pH of the suspension to 11, stir, filter to obtain a solid, wash with ultrapure water until neutral, dry, and perform secondary pyrolysis to obtain iron-modified high-density biochar material. S3. Using epichlorohydrin and diethylenetriamine as reactants, amino groups are grafted onto the surface of iron-modified high-density biochar material through affinity ring-opening and amination reactions to obtain a solidified carrier. S4. Add the solidified carrier to the composite microbial suspension, let it stand for 12 hours, filter to obtain the solid, and air-dry the solid for 24 hours to obtain the composite microbial agent.
[0007] As a further improvement, in step S1, the preparation method of the composite biomass material is as follows: clay is added to deionized water, ultrasonically dispersed to form a uniform suspension, biomass material is added to it, stirred at 700 r / min for 1 h, then the solid is separated and dried to obtain the composite biomass material.
[0008] As a further improvement, the mass ratio of the clay to the biomass material is 1:5~6.
[0009] As a further improvement, the preparation method of the biomass material is as follows: apricot shells, walnut shells, sawdust and ginkgo leaf powder are ball-milled to a particle size of less than 200 mesh and then mixed evenly to obtain the biomass material.
[0010] As a further improvement, the mass-to-volume ratio of the composite biomass material and the tetraethoxysilane is 5g:3~4mL, and the mass ratio of the ferric chloride hexahydrate and the high-density biochar material is 4.5~5:1.
[0011] As a further improvement, step S3 specifically involves: adding iron-modified high-density biochar material to N,N-dimethylformamide, then adding epichlorohydrin, reacting at 85°C for 1 hour, then adding diethylenetriamine at 75°C, stirring for 1 hour, and finally adding triethylamine at 80°C and stirring for 2 hours. After the reaction is complete, the solid material is filtered, washed alternately with ethanol and distilled water until neutral, dried, ground, and passed through a 150-mesh sieve to obtain a solidified carrier.
[0012] As a further improvement, the mass-to-volume ratio of the iron-modified high-density biochar material and the epichlorohydrin is 1 g: 1~2 mL, and the molar ratio of the epichlorohydrin and the diethylenetriamine is 2.2~2.5:1.
[0013] As a further improvement, the composite microbial suspension contains 1×10 8 ~3×10 8 CFU / mL Bacillus cereus and 1×108 ~3×10 8 CFU / mL Pseudomonas putida.
[0014] As a further improvement, the mass-to-volume ratio of the solidified carrier to the composite microbial suspension is 1g:20~30mL.
[0015] The present invention also provides a compound microbial agent for wastewater treatment.
[0016] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: This invention provides a composite microbial agent for wastewater treatment and its preparation method. By adding tetraethoxysilane, the silicon-oxygen skeleton formed by the tetraethoxysilane during pyrolysis can improve the density and mechanical strength of the solidified carrier, preventing it from being quickly washed away by water during the water treatment process, thus achieving better results. However, during the preparation process, it was found that although the high-density biochar material formed by adding tetraethoxysilane can greatly improve its mechanical properties, its surface roughness and porosity are reduced, which in turn leads to a reduction in the number of microorganisms that can be solidified. Therefore, this invention adds clay during the preparation of high-density biochar material to adjust the surface roughness and pore structure of the high-density biochar material and improve its solidification effect on microorganisms.
[0017] In this invention, iron modification and amino grafting are performed on high-density biochar materials to increase the positive charge on the surface of the solidified carrier, which can further increase the loading capacity of microorganisms. The hydroxyl groups on the surface of the iron-modified high-density biochar material obtained after iron modification are further increased, which can improve the amino grafting rate.
[0018] This invention uses a compound of apricot shells, walnut shells, sawdust, and ginkgo leaf powder as biomass materials to adjust the number of active groups on the surface of the solidified carrier, thereby improving the adsorption effect in the water treatment process. Attached Figure Description
[0019] Figure 1 These are the nitrogen adsorption / desorption curves of the solidified carriers of Example 1 and Comparative Examples 1-5, where a, b, c, d, e, and f are the nitrogen adsorption / desorption curves of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, respectively.
[0020] Figure 2 These are scanning electron microscope (SEM) images of the solidified carriers of Example 1, Comparative Example 1, and Comparative Example 5, where a, b, and c are SEM images of Example 1, Comparative Example 1, and Comparative Example 5, respectively.
[0021] Figure 3These are Zeta potential diagrams of the cured carriers of Example 1 and Comparative Examples 1-5, where a, b, c, d, e, and f are Zeta potential diagrams of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, respectively. Detailed Implementation
[0022] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.
[0023] In this invention, Bacillus cereus and Pseudomonas putida are both commercially available. The preparation method of the compound microbial suspension is also existing technology. Specifically, it can be obtained by activating the strain, culturing, centrifuging and concentrating, and resuspending. The specific steps are existing technology.
[0024] Example 1: A method for preparing a compound microbial agent for wastewater treatment, comprising the following steps: S1. Grind 10g of apricot shells, 10g of walnut shells, 20g of sawdust and 20g of ginkgo leaf powder into balls until the particle size is less than 200 mesh, then mix them evenly to obtain biomass material; Add 10g of clay to 500mL of deionized water and sonicate for 30min to make a uniform suspension. Then add 50g of biomass material and stir at 700r / min for 1h. After that, separate the solid material and dry it at 80℃ for 12h to obtain the composite biomass material. 2.5 g of composite biomass material was added to 15 mL of ethanol-water solution with a volume ratio of 1:4. After ultrasonic treatment for 5 min, 2 mL of tetraethoxysilane was added, and the pH of the system was adjusted to 5 with 1 mol / L hydrochloric acid solution. The mixture was stirred for 2 h, and then heated at 85 °C for 15 min to obtain a paste. Under argon conditions, the paste was heated to 600 °C at a heating rate of 5 °C / min and pyrolyzed for 2 h. After cooling to room temperature, the obtained sample was immersed in 1.0 mol / L hydrochloric acid solution and stirred for 1 h. Then it was washed with ultrapure water until the washing solution was neutral, and vacuum dried at 60 °C for 12 h to obtain high-density biochar material. S2. Dissolve 10g of ferric chloride hexahydrate in 200mL of water, then add 2g of high-density biochar material, sonicate for 30min and stir for 1h to obtain a suspension. Adjust the pH of the suspension to 11, stir for 2h, filter to obtain solid, wash with ultrapure water until the washing liquid is neutral, dry for 24 hours, and heat to 600℃ at a heating rate of 5℃ / min under argon atmosphere, hold for 1h, and then cool to room temperature to obtain iron-modified high-density biochar material. S3. Add 2g of iron-modified high-density biochar material to 20mL of N,N-dimethylformamide, then add 4mL (51mmol) of epichlorohydrin, heat in a water bath at 85℃ for 1h, then add 20.4mmol of diethylenetriamine at 75℃ and stir for 1h, then add triethylamine at 80℃ and stir for 2h. After the reaction is complete, filter to obtain solid material, wash the solid material alternately with ethanol and distilled water until the washing liquid is neutral, dry at 70℃ for 24h, grind through a 150-mesh sieve to obtain the solidified carrier; S4 and 2g of solidified carrier were added to 40mL of composite microbial suspension. After standing for 12h, the solid was filtered and then air-dried for 24h to obtain composite microbial agent. The compound microbial suspension contains 1×10 8 CFU / mL Bacillus cereus and 3×10 8 The preparation method of CFU / mL Pseudomonas putida compound microbial suspension is an existing technology.
[0025] Example 2: A method for preparing a compound microbial agent for wastewater treatment, comprising the following steps: S1. Grind 20g of apricot shells, 20g of walnut shells, 30g of sawdust and 30g of ginkgo leaf powder into balls until the particle size is less than 200 mesh, then mix them evenly to obtain biomass material; Add 10g of clay to 500mL of deionized water and sonicate for 30min to make a uniform suspension. Then add 60g of biomass material and stir at 700r / min for 1h. After that, separate the solid material and dry at 80℃ for 12h to obtain the composite biomass material. 2.5 g of composite biomass material was added to 15 mL of ethanol-water solution with a volume ratio of 1:4. After ultrasonic treatment for 5 min, 1.5 mL of tetraethoxysilane was added, and the pH of the system was adjusted to 3 with 1 mol / L hydrochloric acid solution. The mixture was stirred for 2 h, and then heated at 80 °C for 12 min to obtain a paste. Under argon conditions, the paste was heated to 600 °C at a heating rate of 5 °C / min and pyrolyzed for 2 h. After cooling to room temperature, the obtained sample was immersed in 1.0 mol / L hydrochloric acid solution and stirred for 1 h. Then it was washed with ultrapure water until the washing solution was neutral, and vacuum dried at 60 °C for 12 h to obtain high-density biochar material. S2. Dissolve 10g of ferric chloride hexahydrate in 200mL of water, then add 2.22g of high-density biochar material, sonicate for 30min and stir for 1h to obtain a suspension. Adjust the pH of the suspension to 11, stir for 2h, filter to obtain solid, wash with ultrapure water until the washing liquid is neutral, dry for 24 hours, and heat to 600℃ at a heating rate of 5℃ / min under argon atmosphere, hold for 1h, and then cool to room temperature to obtain iron-modified high-density biochar material. S3. Add 2g of iron-modified high-density biochar material to 20mL of N,N-dimethylformamide, then add 2mL (26mmol) of epichlorohydrin, heat in a water bath at 85℃ for 1h, then add 11.8mmol of diethylenetriamine at 75℃ and stir for 1h, then add 2.8g of triethylamine at 80℃ and stir for 2h. After the reaction is complete, filter to obtain solid material, wash the solid material alternately with ethanol and distilled water until the washing liquid is neutral, dry at 70℃ for 24h, grind through a 150-mesh sieve to obtain the solidified carrier; S4 and 2g of solidified carrier were added to 60mL of composite microbial suspension. After standing for 12h, the solid was filtered and then air-dried for 24h to obtain composite microbial agent. The compound microbial suspension contains 3×10 8 CFU / mL Bacillus cereus and 1×10 8 The preparation method of CFU / mL Pseudomonas putida compound microbial suspension is an existing technology.
[0026] Example 3: A method for preparing a compound microbial agent for wastewater treatment, comprising the following steps: S1. Grind 15g of apricot shells, 15g of walnut shells, 25g of sawdust and 25g of ginkgo leaf powder into balls until the particle size is less than 200 mesh, then mix them evenly to obtain biomass material. Add 10g of clay to 500mL of deionized water and sonicate for 30min to make a uniform suspension. Then add 55g of biomass material and stir at 700r / min for 1h. After that, separate the solid material and dry it at 80℃ for 12h to obtain the composite biomass material. 2.5 g of composite biomass material was added to 15 mL of ethanol-water solution with a volume ratio of 1:4. After ultrasonic treatment for 5 min, 1.8 mL of tetraethoxysilane was added, and the pH of the system was adjusted to 4 with 1 mol / L hydrochloric acid solution. The mixture was stirred for 2 h, and then heated at 80 °C for 14 min to obtain a paste. Under argon conditions, the paste was heated to 600 °C at a heating rate of 5 °C / min and pyrolyzed for 2 h. After cooling to room temperature, the obtained sample was immersed in 1.0 mol / L hydrochloric acid solution and stirred for 1 h. Then it was washed with ultrapure water until the washing solution was neutral, and vacuum dried at 60 °C for 12 h to obtain high-density biochar material. S2. Dissolve 10g of ferric chloride hexahydrate in 200mL of water, then add 2.1g of high-density biochar material, sonicate for 30min and stir for 1h to obtain a suspension. Adjust the pH of the suspension to 11, stir for 2h, filter to obtain solid, wash with ultrapure water until the washing liquid is neutral, dry for 24 hours, and heat to 600℃ at a heating rate of 5℃ / min under argon atmosphere, hold for 1h, and then cool to room temperature to obtain iron-modified high-density biochar material. S3. Add 2g of iron-modified high-density biochar material to 20mL of N,N-dimethylformamide, then add 3mL (38.3mmol) of epichlorohydrin, heat in a water bath at 85℃ for 1h, then add 16mmol of diethylenetriamine at 75℃ and stir for 1h, then add 2.8g of triethylamine at 80℃ and stir for 2h. After the reaction is complete, filter to obtain solid material, wash the solid material alternately with ethanol and distilled water until the washing liquid is neutral, dry at 70℃ for 24h, and grind through a 150-mesh sieve to obtain the solidified carrier. S4 and 2g of solidified carrier were added to 50mL of composite microbial suspension. After standing for 12h, the solid was filtered and air-dried for 24h to obtain composite microbial agent. The compound microbial suspension contains 2×10 8 CFU / mL Bacillus cereus and 2×10 8 The preparation method of CFU / mL Pseudomonas putida compound microbial suspension is an existing technology.
[0027] Comparative Example 1: A method for preparing a compound microbial agent for wastewater treatment, comprising the following steps: S1. Grind 10g of apricot shells, 10g of walnut shells, 20g of sawdust and 20g of ginkgo leaf powder into balls until the particle size is less than 200 mesh, then mix them evenly to obtain biomass material; 2.5 g of biomass material was added to 15 mL of ethanol-water solution with a volume ratio of 1:4. After ultrasonic treatment for 5 min, 2 mL of tetraethoxysilane was added, and the pH of the system was adjusted to 5 with 1 mol / L hydrochloric acid solution. The mixture was stirred for 2 h, and then heated at 85 °C for 15 min to obtain a paste. Under argon conditions, the paste was heated to 600 °C at a heating rate of 5 °C / min and pyrolyzed for 2 h. After cooling to room temperature, the obtained sample was immersed in 1.0 mol / L hydrochloric acid solution and stirred for 1 h. Then it was washed with ultrapure water until the washing solution was neutral, and vacuum dried at 60 °C for 12 h to obtain high-density biochar material. S2. Dissolve 10g of ferric chloride hexahydrate in 200mL of water, then add 2g of high-density biochar material, sonicate for 30min and stir for 1h to obtain a suspension. Adjust the pH of the suspension to 11, stir for 2h, filter to obtain solid, wash with ultrapure water until the washing liquid is neutral, dry for 24 hours, and heat to 600℃ at a heating rate of 5℃ / min under argon atmosphere, hold for 1h, and then cool to room temperature to obtain iron-modified high-density biochar material. S3. Add 2g of iron-modified high-density biochar material to 20mL of N,N-dimethylformamide, then add 4mL (51mmol) of epichlorohydrin, heat in a water bath at 85℃ for 1h, then add 20.4mmol of diethylenetriamine at 75℃ and stir for 1h, then add triethylamine at 80℃ and stir for 2h. After the reaction is complete, filter to obtain solid material, wash the solid material alternately with ethanol and distilled water until the washing liquid is neutral, dry at 70℃ for 24h, grind through a 150-mesh sieve to obtain the solidified carrier; S4 and 2g of solidified carrier were added to 40mL of composite microbial suspension. After standing for 12h, the solid was filtered and then air-dried for 24h to obtain composite microbial agent. The compound microbial suspension contains 1×10 8 CFU / mL Bacillus cereus and 3×10 8 The preparation method of CFU / mL Pseudomonas putida compound microbial suspension is an existing technology.
[0028] Comparative Example 2: A method for preparing a compound microbial agent for wastewater treatment, comprising the following steps: S1. Grind 10g of apricot shells, 10g of walnut shells, 20g of sawdust and 20g of ginkgo leaf powder into balls until the particle size is less than 200 mesh, then mix them evenly to obtain biomass material; Add 10g of clay to 500mL of deionized water and sonicate for 30min to make a uniform suspension. Then add 50g of biomass material and stir at 700r / min for 1h. After that, separate the solid material and dry it at 80℃ for 12h to obtain the composite biomass material. 2.5 g of composite biomass material was added to 15 mL of ethanol-water solution with a volume ratio of 1:4. After ultrasonic treatment for 5 min, 2 mL of tetraethoxysilane was added, and the pH of the system was adjusted to 5 with 1 mol / L hydrochloric acid solution. The mixture was stirred for 2 h, and then heated at 85 °C for 15 min to obtain a paste. Under argon conditions, the paste was heated to 600 °C at a heating rate of 5 °C / min and pyrolyzed for 2 h. After cooling to room temperature, the obtained sample was immersed in 1.0 mol / L hydrochloric acid solution and stirred for 1 h. Then it was washed with ultrapure water until the washing solution was neutral, and vacuum dried at 60 °C for 12 h to obtain the solidified carrier. S2 and 2g of solidified carrier were added to 40mL of composite microbial suspension. After standing for 12h, the solid was filtered and then air-dried for 24h to obtain composite microbial agent. The compound microbial suspension contains 1×10 8 CFU / mL Bacillus cereus and 3×10 8 The preparation method of CFU / mL Pseudomonas putida compound microbial suspension is an existing technology.
[0029] Comparative Example 3: A method for preparing a compound microbial agent for wastewater treatment, comprising the following steps: S1. Grind 10g of apricot shells, 10g of walnut shells, 20g of sawdust and 20g of ginkgo leaf powder into balls until the particle size is less than 200 mesh, then mix them evenly to obtain biomass material; Add 10g of clay to 500mL of deionized water and sonicate for 30min to make a uniform suspension. Then add 50g of biomass material and stir at 700r / min for 1h. After that, separate the solid material and dry it at 80℃ for 12h to obtain the composite biomass material. 2.5 g of composite biomass material was added to 15 mL of ethanol-water solution with a volume ratio of 1:4. After ultrasonic treatment for 5 min, 2 mL of tetraethoxysilane was added, and the pH of the system was adjusted to 5 with 1 mol / L hydrochloric acid solution. The mixture was stirred for 2 h, and then heated at 85 °C for 15 min to obtain a paste. Under argon conditions, the paste was heated to 600 °C at a heating rate of 5 °C / min and pyrolyzed for 2 h. After cooling to room temperature, the obtained sample was immersed in 1.0 mol / L hydrochloric acid solution and stirred for 1 h. Then it was washed with ultrapure water until the washing solution was neutral, and vacuum dried at 60 °C for 12 h to obtain high-density biochar material. S2. Add 2g of high-density biochar material to 20mL of N,N-dimethylformamide, then add 4mL (51mmol) of epichlorohydrin, heat in a water bath at 85℃ for 1h, then add 20.4mmol of diethylenetriamine at 75℃, stir for 1h, then add triethylamine at 80℃, stir for 2h. After the reaction is complete, filter to obtain solid material, wash the solid material alternately with ethanol and distilled water until the washing liquid is neutral, dry at 70℃ for 24h, grind through a 150-mesh sieve to obtain the solidified carrier; S3 and 2g of solidified carrier were added to 40mL of composite microbial suspension. After standing for 12h, the solid was filtered and then air-dried for 24h to obtain composite microbial agent. The compound microbial suspension contains 1×10 8 CFU / mL Bacillus cereus and 3×10 8 The preparation method of CFU / mL Pseudomonas putida compound microbial suspension is an existing technology.
[0030] Comparative Example 4: A method for preparing a compound microbial agent for wastewater treatment, comprising the following steps: S1. Grind 20g of ginkgo leaf powder into balls until the particle size is less than 200 mesh, then mix them evenly to obtain biomass material; Add 10g of clay to 500mL of deionized water and sonicate for 30min to make a uniform suspension. Then add 50g of biomass material and stir at 700r / min for 1h. After that, separate the solid material and dry it at 80℃ for 12h to obtain the composite biomass material. 2.5 g of composite biomass material was added to 15 mL of ethanol-water solution with a volume ratio of 1:4. After ultrasonic treatment for 5 min, 2 mL of tetraethoxysilane was added, and the pH of the system was adjusted to 5 with 1 mol / L hydrochloric acid solution. The mixture was stirred for 2 h, and then heated at 85 °C for 15 min to obtain a paste. Under argon conditions, the paste was heated to 600 °C at a heating rate of 5 °C / min and pyrolyzed for 2 h. After cooling to room temperature, the obtained sample was immersed in 1.0 mol / L hydrochloric acid solution and stirred for 1 h. Then it was washed with ultrapure water until the washing solution was neutral, and vacuum dried at 60 °C for 12 h to obtain high-density biochar material. S2. Dissolve 10g of ferric chloride hexahydrate in 200mL of water, then add 2g of high-density biochar material, sonicate for 30min and stir for 1h to obtain a suspension. Adjust the pH of the suspension to 11, stir for 2h, filter to obtain solid, wash with ultrapure water until the washing liquid is neutral, dry for 24 hours, and heat to 600℃ at a heating rate of 5℃ / min under argon atmosphere, hold for 1h, and then cool to room temperature to obtain iron-modified high-density biochar material. S3. Add 2g of iron-modified high-density biochar material to 20mL of N,N-dimethylformamide, then add 4mL (51mmol) of epichlorohydrin, heat in a water bath at 85℃ for 1h, then add 20.4mmol of diethylenetriamine at 75℃ and stir for 1h, then add triethylamine at 80℃ and stir for 2h. After the reaction is complete, filter to obtain solid material, wash the solid material alternately with ethanol and distilled water until the washing liquid is neutral, dry at 70℃ for 24h, grind through a 150-mesh sieve to obtain the solidified carrier; S4 and 2g of solidified carrier were added to 40mL of composite microbial suspension. After standing for 12h, the solid was filtered and then air-dried for 24h to obtain composite microbial agent. The compound microbial suspension contains 1×10 8 CFU / mL Bacillus cereus and 3×10 8 The preparation method of CFU / mL Pseudomonas putida compound microbial suspension is an existing technology.
[0031] Comparative Example 5: A method for preparing a compound microbial agent for wastewater treatment, comprising the following steps: S1. Grind 10g of apricot shells, 10g of walnut shells, 20g of sawdust and 20g of ginkgo leaf powder into balls until the particle size is less than 200 mesh, then mix them evenly to obtain biomass material; 2.5g of biomass material was heated to 600℃ under argon atmosphere at a heating rate of 5℃ / min and pyrolyzed for 2h. After cooling to room temperature, the obtained sample was immersed in 1.0mol / L hydrochloric acid solution and stirred for 1h. Then it was washed with ultrapure water until the washing solution was neutral and vacuum dried at 60℃ for 12h to obtain high-density biochar material. S2. Dissolve 10g of ferric chloride hexahydrate in 200mL of water, then add 2g of high-density biochar material, sonicate for 30min and stir for 1h to obtain a suspension. Adjust the pH of the suspension to 11, stir for 2h, filter to obtain solid, wash with ultrapure water until the washing liquid is neutral, dry for 24 hours, and heat to 600℃ at a heating rate of 5℃ / min under argon atmosphere, hold for 1h, and then cool to room temperature to obtain iron-modified high-density biochar material. S3. Add 2g of iron-modified high-density biochar material to 20mL of N,N-dimethylformamide, then add 4mL (51mmol) of epichlorohydrin, heat in a water bath at 85℃ for 1h, then add 20.4mmol of diethylenetriamine at 75℃ and stir for 1h, then add triethylamine at 80℃ and stir for 2h. After the reaction is complete, filter to obtain solid material, wash the solid material alternately with ethanol and distilled water until the washing liquid is neutral, dry at 70℃ for 24h, grind through a 150-mesh sieve to obtain the solidified carrier; S4 and 2g of solidified carrier were added to 40mL of composite microbial suspension. After standing for 12h, the solid was filtered and then air-dried for 24h to obtain composite microbial agent. The compound microbial suspension contains 1×10 8 CFU / mL Bacillus cereus and 3×10 8 The preparation method of CFU / mL Pseudomonas putida compound microbial suspension is an existing technology.
[0032] Nitrogen adsorption and desorption tests were conducted on the solidified supports obtained in Example 1 and Comparative Examples 1-5. The specific surface area and pore structure of the solidified supports were measured, and the resulting nitrogen adsorption / desorption curves are shown below. Figure 1 As shown in Table 1, a, b, c, d, e, and f are the nitrogen adsorption / desorption curves of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, respectively. The specific surface area and pore structure of the solidified carriers of Example 1 and Comparative Examples 1-5 are shown in Table 1.
[0033] Table 1. Specific surface area and pore structure results of the cured carriers in Example 1 and Comparative Examples 1-5.
[0034]
[0035] Depend on Figure 1 It can be seen that the nitrogen adsorption / desorption curves of the solidified carriers in Example 1 and Comparative Examples 1-5 are all type IV isothermal adsorption curves.
[0036] As shown in Table 1, the solidified carrier of Example 1 has the highest specific surface area and the most pores. The specific surface area and pores of Comparative Examples 2 and 3 are similar to those of Example 1, indicating that iron modification and amino grafting of high-density biochar have little effect on the specific surface area and pores of the solidified carrier. Comparative Example 4 shows a slight decrease compared to Example 1, indicating that the combination of multiple biomass materials can improve the specific surface area and pores of biochar materials. The specific surface area and pores of Comparative Example 1 are significantly lower than those of Example 1, and the specific surface area and pores of Comparative Example 1 are also significantly lower than those of Comparative Example 5. This indicates that the addition of tetraethoxysilane will greatly reduce the surface roughness and pores of biochar materials. The addition of clay can not only improve the effect of adding tetraethoxysilane, but also further improve the surface roughness and pores of biochar materials, and the pore structure also changes.
[0037] Scanning electron microscopy analysis was performed on the cured carriers of Example 1, Comparative Example 1, and Comparative Example 5, such as... Figure 2 The images shown are scanning electron microscope (SEM) images of Example 1, Comparative Example 1, and Comparative Example 5, where a, b, and c are SEM images of Example 1, Comparative Example 1, and Comparative Example 5, respectively.
[0038] Depend on Figure 2 It can be seen that the surface of the curing carrier in Comparative Example 1 is smoother, while the surface roughness of the curing carrier in Example 1 is the greatest, and the surface roughness of Comparative Example 5 is between that of Example 1 and Comparative Example 1.
[0039] The surface charge state of the cured carriers of Example 1 and Comparative Examples 1-5 was tested using the Zeta potential method. Figure 3 As shown, the Zeta potential diagrams of the cured carriers of Example 1 and Comparative Examples 1-5 are shown, where a, b, c, d, e, and f are the Zeta potential diagrams of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, respectively.
[0040] Depend on Figure 3 It can be seen that the isoelectric points of the cured carriers in Example 1 and Comparative Examples 1-5 are 9.20, 9.21, 5.52, 7.57, 8.34, and 8.92, respectively. The biochar material can further increase the number of surface hydroxyl groups after iron modification, and can graft more amino groups during the amino grafting process, which is beneficial to increasing the amount of positive charge on the surface.
[0041] The effect of the compound microbial agent in Example 1 and Comparative Examples 1-5 on PO4 in water was determined. 3- and NH4 + The removal effect.
[0042] A certain amount of ammonium phosphate was dissolved in deionized water to prepare PO4 solution with an initial concentration of 50 mg / L. 3-67.85 mg / L NH4 + For each of the mixed solutions, weigh 0.5 g of the compound microbial agent and add it to 40 mL of the mixed solution. Shake at 30 °C and 200 r / min for 24 h. Then filter through 20 μm filter paper and determine the PO4 in the solution using ultraviolet spectrophotometry. 3- and NH4 + The concentration of the compound microbial agent was calculated to determine its effect on PO4. 3- and NH4 + The removal rate is shown in Table 2.
[0043] Table 2. Effects of compound microbial agents on PO4 3- and NH4 + Removal rate results
[0044]
[0045] As can be seen from Table 2, compared with Example 1, the nitrogen and phosphorus removal effects of Comparative Example 2 and Comparative Example 3 both decreased to a certain extent, and Comparative Example 3 had a slightly higher nitrogen and phosphorus removal effect than Comparative Example 2. This is because the iron modification and amino grafting of biochar can increase the loading of microbial agents, thereby improving the nitrogen and phosphorus removal effect of the composite microbial agents.
[0046] Compared with Example 1, the nitrogen and phosphorus removal effect of Comparative Example 1 was significantly reduced. This is because the addition of only tetraethoxysilane without the addition of clay resulted in a significant reduction in the surface roughness of the solidified carrier, which in turn led to a significant reduction in the loading of the microbial agent.
[0047] Compared with Example 1, the nitrogen and phosphorus removal effect of Comparative Example 4 decreased to a smaller extent. This is because the biomass material in Comparative Example 4 is relatively simple, and the number of functional groups on the surface of the solidified carrier is small, resulting in a decrease in the adsorption effect on nitrogen and phosphorus.
[0048] Compared with Example 1, the nitrogen and phosphorus removal effect of Comparative Example 5 was similar, indicating that the synergy between clay and tetraethoxysilane can improve the mechanical strength and density of the solidified carrier without reducing the load on the solidified carrier for microorganisms.
[0049] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for preparing a compound microbial agent for wastewater treatment, characterized in that, Includes the following steps: S1. Using clay and biomass materials as composite biomass materials, the composite biomass materials are mixed with an ethanol aqueous solution, ultrasonically treated, and then tetraethoxysilane is added to adjust the pH to 3-5. After stirring for 2 hours, the mixture is heated at 80-85℃ for 12-15 minutes to obtain a paste. The paste is then subjected to pyrolysis once and acid-modified to obtain high-density biochar materials. The biomass material comprises, by weight, the following components: 1-2 parts apricot shells, 1-2 parts walnut shells, 2-3 parts sawdust, and 2-3 parts ginkgo leaf powder; S2. Dissolve ferric chloride hexahydrate in water, add high-density biochar material, and stir ultrasonically to obtain a suspension. Adjust the pH of the suspension to 11, stir, filter to obtain a solid, wash with ultrapure water until neutral, dry, and perform secondary pyrolysis to obtain iron-modified high-density biochar material. S3. Using epichlorohydrin and diethylenetriamine as reactants, amino groups are grafted onto the surface of iron-modified high-density biochar material through affinity ring-opening and amination reactions to obtain a solidified carrier. S4. Add the solidified carrier to the composite microbial suspension, let it stand for 12 hours, filter to obtain the solid, and air-dry the solid for 24 hours to obtain the composite microbial agent.
2. The method for preparing the composite microbial agent for wastewater treatment according to claim 1, characterized in that, In step S1, the preparation method of the composite biomass material is as follows: clay is added to deionized water, ultrasonically dispersed to form a uniform suspension, biomass material is added to it, stirred at 700 r / min for 1 h, then the solid is separated and dried to obtain the composite biomass material.
3. The method for preparing the composite microbial agent for wastewater treatment according to claim 2, characterized in that, The mass ratio of the clay to the biomass material is 1:5~6.
4. The method for preparing the composite microbial agent for wastewater treatment according to claim 3, characterized in that, The preparation method of the biomass material is as follows: apricot shells, walnut shells, sawdust and ginkgo leaf powder are ball-milled to a particle size of less than 200 mesh and then mixed evenly to obtain the biomass material.
5. The method for preparing the composite microbial agent for wastewater treatment according to claim 1, characterized in that, The mass-to-volume ratio of the composite biomass material and the tetraethoxysilane is 5g:3~4mL, and the mass ratio of the ferric chloride hexahydrate and the high-density biochar material is 4.5~5:
1.
6. The method for preparing the composite microbial agent for wastewater treatment according to claim 1, characterized in that, Step S3 is as follows: Iron-modified high-density biochar material is added to N,N-dimethylformamide, then epichlorohydrin is added, and the reaction is carried out at 85°C for 1 hour. Then, diethylenetriamine is added at 75°C, and the mixture is stirred for 1 hour. After stirring, triethylamine is added at 80°C and the mixture is stirred for 2 hours. After the reaction is completed, the solid material is obtained by filtration, and the solid material is washed alternately with ethanol and distilled water until neutral. After drying, it is ground and passed through a 150-mesh sieve to obtain a solidified carrier.
7. The method for preparing the composite microbial agent for wastewater treatment according to claim 6, characterized in that, The mass-to-volume ratio of the iron-modified high-density biochar material to the epichlorohydrin is 1 g: 1~2 mL, and the molar ratio of the epichlorohydrin to the diethylenetriamine is 2.2~2.5:
1.
8. The method for preparing the composite microbial agent for wastewater treatment according to claim 1, characterized in that, The composite microbial suspension contains 1×10 8 ~3×10 8 CFU / mL Bacillus cereus and 1×10 8 ~3×10 8 CFU / mL Pseudomonas putida.
9. The method for preparing the composite microbial agent for wastewater treatment according to claim 1, characterized in that, The mass-to-volume ratio of the solidified carrier to the composite microbial suspension is 1g:20~30mL.
10. A compound microbial agent for wastewater treatment, characterized in that, The composite microbial agent is prepared by the method for preparing the composite microbial agent for wastewater treatment as described in claim 1.