Microbial fertilizer for degrading soil organic pesticides

Abstract

The application discloses a kind of microorganism fertilizers degrading soil organic pesticide, it is related to fertilizer technical field;The microorganism fertilizer degrading soil organic pesticide is composed of Fe / Mg bimetallic load type NS doped biochar, MR-1 strain, sodium lactate, sodium alginate, calcium chloride, chicken manure and bentonite;MR-1 bacteria liquid is attached in the pore of Fe / Mg bimetallic load type NS doped biochar, then it is wrapped and protected by the gel layer formed by sodium alginate and calcium chloride, improve the load stability, loading capacity of bacterial body and the activity of flora, and, MR-1 bacterial body and biochar base material are synergistically assembled and act on organic pesticide, significantly improve the effectiveness and high efficiency of degradation, eliminate the adverse effects of pesticide, and be conducive to crop yield increase.

Description

Technical Field

[0001] This invention belongs to the field of fertilizer technology, specifically referring to a microbial fertilizer that degrades organic pesticides in soil. Background Technology

[0002] Organic pesticides are widely used in agricultural production to control pests and diseases, but their long-term use and residues can cause various harms to the soil ecosystem. Organic pesticide residues in the soil (such as organophosphates and organochlorines) not only kill or inhibit beneficial microorganisms such as nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and actinomycetes, leading to a decline in soil fertility, but also significantly inhibit the activity of various soil enzymes, resulting in reduced efficiency of nitrogen and phosphorus nutrient conversion, slow decomposition of organic matter, and are detrimental to crop growth and yield. More seriously, organic pesticides have a half-life of several years or even decades, making them easy to accumulate in the soil, difficult to degrade naturally, and enter the food chain through crop absorption, ultimately endangering human health. Existing methods for remediating soil contaminated by organic pesticides mainly include physical remediation, chemical remediation, and bioremediation. Among them, physical remediation is relatively expensive, and chemical remediation is also relatively expensive, and improper control can easily lead to secondary pollution. Bioremediation, due to its low cost and safety, is increasingly being used to degrade pesticide residues in soil.

[0003] The existing technology currently suffers from the following main problems: The activity of microorganisms is easily affected by adverse soil environment, which limits their degradation effect on organic pesticides. Moreover, relying solely on the action of microorganisms, the degradation efficiency of organic pesticides in soil is low, and it is impossible to effectively and efficiently improve the problem of pesticide residues. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the present invention proposes a microbial fertilizer for degrading soil organic pesticides, comprising the following components in parts by weight: 50-60 parts of Fe / Mg bimetallic supported NS-doped biochar, 1-3 parts of MR-1 strain, 10-15 parts of sodium lactate, 10-20 parts of sodium alginate, 10-20 parts of calcium chloride, 30-40 parts of chicken manure, and 10-20 parts of bentonite.

[0005] The Fe / Mg bimetallic supported NS-doped biochar comprises the following components in parts by weight: 20-30 parts NS co-doped biochar, 10-20 parts ferric chloride hexahydrate, 5-10 parts magnesium chloride hexahydrate, 1-3 parts calcium peroxide, 5-10 parts humic acid, and 0.5-1 parts hexadecyltrimethylammonium bromide.

[0006] The preparation method of the Fe / Mg bimetallic supported NS-doped biochar specifically includes the following steps: (1) Dry municipal sludge in an oven at 70-80℃ for 24 hours, grind it with a grinder and pass it through a 100-mesh sieve. Weigh 20.0-30.0g of sludge powder and mix it evenly with 10.0-15.0g of ammonium persulfate. Add 300mL of deionized water and stir continuously at 60℃ for 18-24 hours under sealed conditions. Then transfer the mixture to an oven at 80-90℃ and dry it for 48 hours. After complete dehydration, grind and disperse the mixture, place it in a ceramic boat, and pyrolyze it at 280-300℃ under nitrogen protection in a tube furnace for 1- In 2 hours, the porous structure and high specific surface area of ​​biochar can adsorb pesticides such as organochlorine and organophosphorus in the soil, reduce their mobility and bioavailability, and indirectly promote degradation. At the same time, N and S functional groups can catalyze the decomposition of pesticides through surface redox reactions or generate reactive oxygen species to participate in degradation. Biochar also provides habitat and nutrient supply for microorganisms, promotes their growth and accelerates the biodegradation of organic pesticides. Furthermore, biochar can regulate soil pH, water retention and aeration, optimize the living conditions of microorganisms, and obtain N / S co-doped biochar. (2) First, disperse the NS co-doped biochar described in step (1) in 300 mL of deionized water, then add humic acid and hexadecyltrimethylammonium bromide, stir together for 5-10 min, sonicate for 20-30 min, then add 1.0-2.0 g of ferric chloride hexahydrate and 0.5-1.0 g of magnesium chloride hexahydrate. Place the mixed liquid in a heat-collecting constant-temperature magnetic stirrer at 50-60℃, slowly add an equal volume of 2-3% citric acid solution, and continue stirring for 120-180 min. Then raise the temperature to 80-90℃ and continue stirring until the solution is concentrated and turns into a gel. Mix 0.1-0.3 g of calcium peroxide with the gel and grind it. Transfer it to a 90℃ oven and dry for 10-12 h. Then, crush, grind, and sieve through a 100-200 mesh screen. Finally, the mixture was transferred to a ceramic boat and placed in a tube furnace under nitrogen protection. The temperature was first increased to 300℃ at a rate of 5℃ / min, then further increased to 650-700℃, and pyrolyzed for 1-2 hours. In this process, Fe / Mg oxide nanoparticles are uniformly dispersed in the mesopores of NS co-doped biochar. After humic acid carbonization, oxygen-containing functional groups are retained and distributed at the edge of the biochar framework. Calcium peroxide is partially converted into calcium carbonate microcrystals, dispersed in the biochar pores, serving as a slow-release source of H2O2 to ensure the Fenton-like reaction. After pyrolysis, hexadecyltrimethylammonium bromide leaves a hydrophobic carbon layer that covers part of the Fe / Mg oxide nanoparticle surface, thus forming a stable hierarchical porous structure. This provides more adsorption-catalytic sites, greatly improving the degradation efficiency of water-soluble and fat-soluble pesticides. Fe provides catalytically active sites, through which Fe... 3+ / Fe 2+Mg participates in the Fenton-like reaction, activating peroxides and H2O2 in the soil to generate reactive oxygen species, which directly oxidize organic pesticides. Mg not only enhances structural stability and regulates surface charge, but also promotes electron transfer and buffers soil pH, ensuring the Fenton-like reaction remains effective within a pH range of 5-8. The quinone groups of humic acid can accept / donate electrons, accelerating the reduction to Fe. 2+ The process promotes the continuous generation of reactive oxygen species. Hexadecyltrimethylammonium bromide forms micelles in solution, which can serve as templates for the growth of nano-Fe / Mg oxides, preventing metal aggregation and increasing the exposure rate of active sites. The hydrophobic surface modified with hexadecyltrimethylammonium bromide can accelerate the transfer of electrons from biochar to adsorbed pesticides, enhancing the Fe... 3+ / Fe 2+ The recycling efficiency was improved to obtain Fe / Mg bimetallic supported NS-doped biochar; Preferably, in step (2), the amount of humic acid added is 0.5-1.0g. As a natural oxidant, humic acid can form a complex with Fe / Mg, improve the dispersibility of metal, reduce the risk of metal dissolution, and can also adsorb organic pesticides through its own hydrophobic effect, enrich them at the Fe / Mg active sites, and increase the local reaction concentration. Preferably, in step (2), the amount of hexadecyltrimethylammonium bromide added is 0.05-0.1g. The cations of hexadecyltrimethylammonium bromide are adsorbed on the surface of biochar through electrostatic interaction, and the long-chain alkyl groups are arranged outward to form a hydrophobic layer, which effectively improves the adsorption of non-polar pesticides by biochar. Furthermore, the hydrophobic-hydrophobic interaction between the alkyl chain of hexadecyltrimethylammonium bromide and the benzene ring of the pesticide further enhances the adsorption capacity of the pesticide.

[0007] This invention also provides a method for preparing a microbial fertilizer that degrades soil organic pesticides, specifically including the following steps: S1. After activating 1.0-3.0 g of MR-1 strain, inoculate it into LB liquid medium at a volume of 1-3% of the LB liquid medium. Incubate at 26-30℃ and 160-180 rpm for 12 h. Centrifuge and wash the collected bacterial cells twice with inorganic salt liquid medium. Then resuspend the bacterial cells in sterile water and adjust the bacterial concentration to 2×10⁻⁶. 8 The process yielded highly active and environmentally adaptable MR-1 bacterial cells at CFU / mL, which can better enhance soil fertility by activating nutrients, regulating the microbial community, and improving the soil redox state, thus positively impacting crop growth, development, and yield. S2. Add 1.0-2.0 g of sodium alginate to 100 mL of water at 60-70℃ and stir for 20-30 min. Cool to 30-35℃ and add sodium lactate. Stir for 5-10 min and then mix thoroughly with the MR-1 bacterial solution described in step S1. Add the mixture dropwise to the surface of Fe / Mg bimetallic supported NS-doped biochar using a syringe pump at a rate of 0.5-1 mL / min. Let it stand for 5-10 min to fully impregnate the biochar. Incubate under anaerobic conditions at room temperature for 2-4 h. Then immerse the biochar in 100 mL of 1-2% calcium chloride solution for a crosslinking reaction for 10-15 min. Remove the biochar and wash it 3-5 times with sterile PBS solution. Freeze-dry the biochar. In the dry environment, MR-1 bacteria are tightly attached to the pores of Fe / Mg bimetallic supported NS-doped biochar through a protective layer of sodium alginate-calcium chloride. This reduces the impact of adverse conditions such as pH and temperature in the soil on bacterial activity, increases the loading and activity of the bacterial community, and facilitates the synergistic degradation of organic pesticides by bacteria and materials, significantly improving the effectiveness and efficiency of degradation. The gel layer maintains suitable humidity and low oxygen conditions, which meets the anaerobic metabolic requirements of MR-1. The gel layer delays the diffusion of H2O2 and prolongs the action time of reactive oxygen species, which is conducive to improving the pesticide degradation efficiency, resulting in MR-1 supported Fe / Mg bimetallic NS-doped biochar composite material. S3. After fermenting chicken manure at 50-55℃ for 5-7 days, the pre-fermented chicken manure, bentonite, and the MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material described in step S2 are mixed evenly. The MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material not only adsorbs multi-effect nutrients through its porous and gel structures, reducing nutrient loss and improving soil water retention and aeration, thereby increasing fertilizer utilization, but also exerts the nitrogen-fixing, phosphorus-solubilizing, and plant growth-promoting effects of MR-1. Furthermore, after eliminating the inhibitory effect of pesticides on fertilizer efficiency, it also enhances soil phosphatase activity, which is conducive to improving soil fertility and increasing crop yield and income, thus obtaining a microbial fertilizer that degrades soil organic pesticides. Preferably, in step S1, the MR-1 strain was purchased from the China Center for Type Culture Collection, numbered CCTCAB2013238. MR-1 can reduce heavy metals or organic pollutants and promote degradation through c-type cytochrome-mediated electron transfer. It can also secrete hydrolytic enzymes and dehalogenases to participate in the desulfurization and dechlorination reactions of organic pesticides, thereby effectively degrading residual pesticides in the soil. Preferably, in step S2, the amount of sodium lactate added is 1.0-1.5g. Sodium lactate acts as an isotonic regulator to improve the hypertonic environment generated during the cross-linking process, prevent the lysis of MR-1 cells, and provide energy source and metabolic substrate for the growth of MR-1 cells. Sodium lactate can also form a glassy matrix during the freeze-drying process, reducing the mechanical damage of ice crystals to the MR-1 cell membrane. Preferably, in step S3, the mixing speed is 15-20 rpm and the mixing time is 3-5 min. Controlling the mixing speed at a lower speed can reduce the risk of material breakage and ensure the survival rate of the bacteria.

[0008] The beneficial effects achieved by this invention are as follows: This invention improves the loading stability, loading capacity, and activity of the bacteria by attaching MR-1 bacterial culture to the pores of Fe / Mg bimetallic supported NS-doped biochar and then encapsulating and protecting it with a gel layer formed by sodium alginate and calcium chloride. Furthermore, the synergistic assembly of MR-1 bacteria and biochar-based materials significantly enhances the effectiveness and efficiency of degradation of organic pesticides, eliminating the adverse effects of pesticides and promoting increased crop yields and income. In the Fe / Mg bimetallic supported NS-doped biochar, NS-co-doped biochar serves as the basic carrier, with Fe / Mg oxide nanoparticles uniformly dispersed in the biochar mesopores. After humic acid carbonization, oxygen-containing functional groups are retained and distributed at the edge of the biochar framework. Calcium peroxide is partially converted into calcium carbonate microcrystals, dispersed in the pores of biochar, serving as a slow-release source of H2O2 to ensure the Fenton-like reaction. After pyrolysis, hexadecyltrimethylammonium bromide leaves a hydrophobic carbon layer that covers part of the Fe / Mg oxide nanoparticle surface, thus forming a stable hierarchical porous structure with high specific surface area and abundant functional groups, providing more adsorption-catalytic sites. This structure not only adsorbs and degrades organic pesticides but also provides attachment sites for microorganisms and enhances soil water and fertilizer retention. Humic acid can chelate Fe / Mg to form a slow-release complex, providing a continuous source of iron and magnesium nutrients for microorganisms, maintaining the degradation activity of the strains. Its quinone group can act as an electron mediator, accelerating the degradation of Fe... 3+ / Fe 2+The Fe / Mg bimetallic compound optimizes the Fenton-like reaction efficiency by maintaining a pH environment, oxidizing and decomposing organic pesticides. It also acts as an electron acceptor, supporting the anaerobic respiratory chain of bacteria and maintaining energy metabolism activity. Furthermore, it neutralizes soil acidity, preventing bacterial inactivation at low pH. The hydrophobic modification of hexadecyltrimethylammonium bromide significantly improves the degradation efficiency of both water-soluble and fat-soluble pesticides. It also promotes uniform dispersion of Fe / Mg oxidized nanoparticles through electrostatic interactions, increasing the exposure rate of active sites and ensuring contact fixation during bacterial loading. In the MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material, MR-1 bacteria are tightly attached to the pores of the Fe / Mg bimetallic-loaded NS-doped biochar through a sodium alginate-calcium chloride protective layer, reducing the impact of adverse soil conditions such as pH and temperature on bacterial activity and preserving... The invention demonstrates the loading and activity of the microbial community, which is conducive to maximizing the synergistic effect of the microorganisms and materials, significantly improving the degradation efficiency of organic pesticides. Specifically, the gel layer maintains suitable humidity and low-oxygen conditions, meeting the anaerobic metabolic needs of MR-1. The gel layer also delays H2O2 diffusion, thereby extending the action time of reactive oxygen species, which is beneficial to improving pesticide degradation efficiency. The gel structure also improves soil water retention and permeability, thereby increasing fertilizer utilization. Simultaneously, it leverages the nitrogen fixation, phosphorus solubilization, and plant growth promotion functions of MR-1 microorganisms, which is beneficial to improving soil fertility and increasing crop yield. This invention uses Fe / Mg bimetallic supported NS-doped biochar, MR-1 strain, sodium lactate, sodium alginate, calcium chloride, chicken manure, and bentonite to prepare a microbial fertilizer for degrading organic pesticides in soil. This effectively improves the activity of the microorganisms, significantly enhances the degradation efficiency of organic pesticides, and is beneficial to increasing crop yield and income. Attached Figure Description

[0009] Figure 1 This is a scanning electron microscope image of the Fe / Mg bimetallic supported NS-doped biochar prepared in Example 1 of this invention; Figure 2 The figures show the viable cell counts of Examples 1-4 and Comparative Examples 1-4 of the present invention. Figure 3 The graphs show the degradation rate results of Examples 1-4 and Comparative Examples 1-4 of the present invention. Figure 4 The graph shows the yield increase results of Examples 1-4 and Comparative Examples 1-4 of the present invention. Detailed Implementation

[0010] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0011] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0012] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; unless otherwise specified, the experimental materials used in the following embodiments are all purchased from commercial channels. Example

[0013] This embodiment proposes a microbial fertilizer for degrading soil organic pesticides, comprising the following components in parts by weight: 60 parts Fe / Mg bimetallic supported NS-doped biochar, 3 parts MR-1 strain, 15 parts sodium lactate, 20 parts sodium alginate, 20 parts calcium chloride, 40 parts chicken manure, and 20 parts bentonite.

[0014] Fe / Mg bimetallic supported NS-doped biochar comprises the following components in parts by weight: 30 parts NS co-doped biochar, 20 parts ferric chloride hexahydrate, 10 parts magnesium chloride hexahydrate, 3 parts calcium peroxide, 10 parts humic acid, and 1 part hexadecyltrimethylammonium bromide.

[0015] The preparation method of Fe / Mg bimetallic supported NS-doped biochar includes the following steps: (1) The municipal sludge was dried in an 80℃ oven for 24 hours, pulverized by a grinder and passed through a 100-mesh sieve. 30.0g of sludge powder was weighed and mixed with 15.0g of ammonium persulfate. 300mL of deionized water was added and stirred continuously at 60℃ for 24 hours under sealed conditions. The mixture was then transferred to a 90℃ oven for 48 hours to dry completely. After dehydration, it was ground and dispersed and placed in a ceramic boat. Nitrogen gas was introduced into the tube furnace for protection and pyrolysis at 300℃ for 2 hours. The porous structure and high specific surface area of ​​biochar can adsorb pesticides such as organochlorine and organophosphorus in the soil, reduce their migration and bioavailability, and indirectly promote degradation. At the same time, N and S functional groups can catalyze the decomposition of pesticides through surface redox reactions or generate active oxygen to participate in degradation. Biochar also provides habitat and nutrient supply for microorganisms, promotes their growth and accelerates the biodegradation of organic pesticides. In addition, biochar can also regulate the pH, water retention and aeration of the soil and optimize the living conditions of microorganisms to obtain NS co-doped biochar. (2) The NS co-doped biochar described in step (1) is first dispersed in 300 mL of deionized water, and then humic acid and hexadecyltrimethylammonium bromide are added. The amount of humic acid added is 1.0 g. Humic acid, as a natural oxidant, can form a complex with Fe / Mg, improve the dispersibility of the metal, reduce the risk of metal dissolution, and can also adsorb organic pesticides through its own hydrophobic effect, enriching them at the Fe / Mg active sites and increasing the local reaction concentration. The amount of hexadecyltrimethylammonium bromide added is 0.1 g. The cation of hexadecyltrimethylammonium bromide is... The ions are adsorbed onto the surface of biochar through electrostatic interactions, with long-chain alkyl groups arranged outwards to form a hydrophobic layer, effectively improving the adsorption of non-polar pesticides by biochar. Furthermore, the hydrophobic-hydrophobic interaction between the alkyl chain of hexadecyltrimethylammonium bromide and the benzene ring of the pesticide further enhances the adsorption capacity. The mixture is stirred for 10 minutes, ultrasonically treated for 30 minutes, and then 2.0 g of ferric chloride hexahydrate and 1.0 g of magnesium chloride hexahydrate are added. The mixture is placed in a 60°C thermostatically heated magnetic stirrer, and an equal volume of 3% (by mass) of [a specific ingredient] is slowly added dropwise. A citric acid solution was continuously stirred for 180 min, then the temperature was raised to 90℃, and stirring continued until the solution concentrated and turned into a gel. 0.3 g of calcium peroxide was mixed with the gel and ground, then transferred to a 90℃ oven to dry for 12 h. After crushing, grinding, and sieving through a 200-mesh sieve, the mixture was finally transferred to a ceramic boat and placed in a tube furnace under nitrogen protection. The temperature was first raised to 300℃ at a rate of 5℃ / min, then to 700℃, and pyrolyzed for 2 h. In this process, Fe / Mg oxide nanoparticles were uniformly dispersed in the NS co-doped biofilm. In the mesopores of biochar, humic acid, after carbonization, retains oxygen-containing functional groups distributed at the edges of the biochar framework. Calcium peroxide is partially converted into calcium carbonate microcrystals, dispersed within the biochar pores, serving as a slow-release source of H2O2 to ensure the Fenton-like reaction. After pyrolysis, hexadecyltrimethylammonium bromide leaves a hydrophobic carbon layer that covers part of the Fe / Mg oxide nanoparticle surface, thus forming a stable hierarchical porous structure. This provides more adsorption-catalytic sites, significantly improving the degradation efficiency of both water-soluble and fat-soluble pesticides. Fe provides catalytically active sites, through which Fe... 3+ / Fe 2+ Mg participates in the Fenton-like reaction, activating peroxides and H2O2 in the soil to generate reactive oxygen species, which directly oxidize organic pesticides. Mg not only enhances structural stability and regulates surface charge, but also promotes electron transfer and buffers soil pH, ensuring the Fenton-like reaction remains effective within a pH range of 5-8. The quinone groups of humic acid can accept / donate electrons, accelerating the reduction to Fe. 2+The process promotes the continuous generation of reactive oxygen species. Hexadecyltrimethylammonium bromide forms micelles in solution, which can serve as templates for the growth of nano-Fe / Mg oxides, preventing metal aggregation and increasing the exposure rate of active sites. The hydrophobic surface modified with hexadecyltrimethylammonium bromide can accelerate the transfer of electrons from biochar to adsorbed pesticides, enhancing the Fe... 3+ / Fe 2+ The recycling efficiency was improved to obtain Fe / Mg bimetallic supported NS-doped biochar.

[0016] This embodiment provides a method for preparing a microbial fertilizer that degrades soil organic pesticides, specifically including the following steps: S1. After activating 3.0g of MR-1 strain, it was inoculated into LB liquid medium. MR-1 strain was purchased from the China Center for Type Culture Collection (CCTCCAB2013238). MR-1 can reduce heavy metals or organic pollutants and promote their degradation through c-type cytochrome-mediated electron transfer. It can also secrete hydrolases and dehalogenases, participating in the desulfurization and dechlorination reactions of organic pesticides, thereby effectively degrading pesticide residues in the soil. The inoculation amount was 3% of the volume of LB liquid medium. The culture was carried out in a shaking incubator at 30℃ and 180rpm for 12h. After centrifugation, the collected bacterial cells were washed twice with inorganic salt liquid medium, and then the bacterial resuspended in sterile water to adjust the bacterial concentration to 2×10⁻⁶. 8 The process yielded highly active and environmentally adaptable MR-1 bacterial cells at CFU / mL, which can better enhance soil fertility by activating nutrients, regulating the microbial community, and improving the soil redox state, thus positively impacting crop growth, development, and yield. S2. Add 2.0g of sodium alginate to 100mL of water at 70℃ and stir for 30min. After cooling to 35℃, add 1.5g of sodium lactate. Sodium lactate acts as an isotonic regulator to improve the hypertonic environment generated during cross-linking, prevent the lysis of MR-1 bacterial cells, and provide energy and metabolic substrates for the growth of MR-1 bacteria. Sodium lactate can also form a glassy matrix during freeze-drying, reducing mechanical damage to the MR-1 cell membrane caused by ice crystals. Stir for 10min, then mix evenly with the MR-1 bacterial solution described in step S1. Add the mixture dropwise to the surface of Fe / Mg bimetallic supported NS-doped biochar using a syringe pump at a rate of 1mL / min. Let stand for 10min to fully impregnate the surface, incubate under anaerobic conditions at room temperature for 4h, and then immerse in 100mL of water. In a 2% calcium chloride solution, the cross-linking reaction was carried out for 15 min. The mixture was then removed, washed 5 times with sterile PBS solution, and freeze-dried. The MR-1 cells were tightly attached to the pores of the Fe / Mg bimetallic supported NS-doped biochar through the protective layer of sodium alginate-calcium chloride. This reduced the influence of adverse conditions such as pH and temperature in the soil on the activity of the cells, increased the loading and activity of the bacterial community, and facilitated the synergistic degradation of organic pesticides by the cells and the material. This significantly improved the effectiveness and efficiency of the degradation. The gel layer maintained suitable humidity and low oxygen conditions, which met the anaerobic metabolic requirements of MR-1. The gel layer delayed the diffusion of H2O2 and prolonged the action time of reactive oxygen species, which helped to improve the pesticide degradation efficiency. Thus, the Fe / Mg bimetallic NS-doped biochar composite material loaded with MR-1 was obtained. S3. After fermenting chicken manure at 55℃ for 7 days, the pre-fermented chicken manure, bentonite, and the MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material described in step S2 are mixed evenly at a speed of 20 rpm for 5 minutes. Controlling the mixing speed at a low speed can reduce the risk of material breakage and ensure the survival rate of the microorganisms. The MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material not only adsorbs multi-effect nutrients through its porous and gel structures, reducing nutrient loss and improving soil water retention and aeration, thereby increasing fertilizer utilization, but also exerts the nitrogen fixation, phosphorus solubilization, and plant growth promotion effects of MR-1. Furthermore, after eliminating the inhibitory effect of pesticides on fertilizer efficiency, it also enhances soil phosphatase activity, which is conducive to improving soil fertility and increasing crop yield and income, thus obtaining a microbial fertilizer that degrades soil organic pesticides.

[0017] In this embodiment, the microstructure of the prepared Fe / Mg bimetallic supported NS-doped biochar was observed using scanning electron microscopy. Figure 1 This is a 1000x magnified SEM image of the Fe / Mg bimetallic supported NS-doped biochar prepared in Example 1. Figure 1The Fe / Mg bimetallic supported NS-doped biochar prepared in this embodiment exhibits a multi-level and rich pore structure. Example

[0018] This embodiment proposes a microbial fertilizer for degrading soil organic pesticides, comprising the following components in parts by weight: 50 parts Fe / Mg bimetallic supported NS-doped biochar, 1 part MR-1 strain, 10 parts sodium lactate, 10 parts sodium alginate, 10 parts calcium chloride, 30 parts chicken manure, and 10 parts bentonite.

[0019] Fe / Mg bimetallic supported NS-doped biochar comprises the following components in parts by weight: 20 parts NS co-doped biochar, 10 parts ferric chloride hexahydrate, 5 parts magnesium chloride hexahydrate, 1 part calcium peroxide, 5 parts humic acid, and 0.5 parts cetyltrimethylammonium bromide.

[0020] The preparation method of Fe / Mg bimetallic supported NS-doped biochar includes the following steps: (1) The municipal sludge was dried in a 70℃ oven for 24 hours, pulverized by a grinder and passed through a 100-mesh sieve. 20.0g of sludge powder was weighed and mixed with 10.0g of ammonium persulfate. 300mL of deionized water was added and stirred continuously at 60℃ for 18 hours under sealed conditions. The mixture was then transferred to an 80℃ oven for 48 hours to dry completely. After dehydration, it was ground and dispersed and placed in a ceramic boat. Nitrogen gas was introduced into the tube furnace for protection and pyrolysis was carried out at 280℃ for 1 hour. The porous structure and high specific surface area of ​​biochar can adsorb pesticides such as organochlorine and organophosphorus in the soil, reduce their migration and bioavailability, and indirectly promote degradation. At the same time, N and S functional groups can catalyze the decomposition of pesticides through surface redox reactions or generate active oxygen to participate in degradation. Biochar also provides habitat and nutrient supply for microorganisms, promotes their growth and accelerates the biodegradation of organic pesticides. In addition, biochar can also regulate the pH, water retention and aeration of the soil and optimize the living conditions of microorganisms to obtain NS co-doped biochar. (2) The NS co-doped biochar described in step (1) is first dispersed in 300 mL of deionized water, and then humic acid and hexadecyltrimethylammonium bromide are added. The amount of humic acid added is 0.5 g. As a natural oxidant, humic acid can form a complex with Fe / Mg, improve the dispersibility of the metal, reduce the risk of metal leaching, and can also adsorb organic pesticides through its own hydrophobic effect, enriching them at the Fe / Mg active sites and increasing the local reaction concentration. The amount of hexadecyltrimethylammonium bromide added is 0.05 g. The cation of hexadecyltrimethylammonium bromide is... Ions are adsorbed onto the surface of biochar via electrostatic interactions, with long-chain alkyl groups aligning outwards to form a hydrophobic layer. This effectively improves the adsorption of non-polar pesticides by biochar. Furthermore, the hydrophobic-hydrophobic interaction between the alkyl chain of hexadecyltrimethylammonium bromide and the benzene ring of the pesticide further enhances the adsorption capacity. The mixture is stirred for 5 minutes, ultrasonically treated for 20 minutes, and then 1.0 g of ferric chloride hexahydrate and 0.5 g of magnesium chloride hexahydrate are added. The mixture is placed in a 50°C thermostatically heated magnetic stirrer, and an equal volume of 2% (by mass) of [a specific ingredient / component] is slowly added dropwise. A citric acid solution was continuously stirred for 120 minutes, then the temperature was raised to 80°C, and stirring continued until the solution concentrated and turned into a gel. 0.1 g of calcium peroxide was mixed with the gel and ground, then transferred to a 90°C oven to dry for 10 hours. After crushing, grinding, and sieving through a 100-mesh sieve, the mixture was finally transferred to a ceramic boat and placed in a tube furnace under nitrogen protection. The temperature was first raised to 300°C at a rate of 5°C / min, then to 650°C, and pyrolyzed for 1 hour. In this process, Fe / Mg oxide nanoparticles were uniformly dispersed in the NS co-doped biofilm. In the mesopores of biochar, humic acid, after carbonization, retains oxygen-containing functional groups distributed at the edges of the biochar framework. Calcium peroxide is partially converted into calcium carbonate microcrystals, dispersed within the biochar pores, serving as a slow-release source of H2O2 to ensure the Fenton-like reaction. After pyrolysis, hexadecyltrimethylammonium bromide leaves a hydrophobic carbon layer that covers part of the Fe / Mg oxide nanoparticle surface, thus forming a stable hierarchical porous structure. This provides more adsorption-catalytic sites, significantly improving the degradation efficiency of both water-soluble and fat-soluble pesticides. Fe provides catalytically active sites, through which Fe... 3+ / Fe 2+ Mg participates in the Fenton-like reaction, activating peroxides and H2O2 in the soil to generate reactive oxygen species, which directly oxidize organic pesticides. Mg not only enhances structural stability and regulates surface charge, but also promotes electron transfer and buffers soil pH, ensuring the Fenton-like reaction remains effective within a pH range of 5-8. The quinone groups of humic acid can accept / donate electrons, accelerating the reduction to Fe. 2+The process promotes the continuous generation of reactive oxygen species. Hexadecyltrimethylammonium bromide forms micelles in solution, which can serve as templates for the growth of nano-Fe / Mg oxides, preventing metal aggregation and increasing the exposure rate of active sites. The hydrophobic surface modified with hexadecyltrimethylammonium bromide can accelerate the transfer of electrons from biochar to adsorbed pesticides, enhancing the Fe... 3+ / Fe 2+ The recycling efficiency was improved to obtain Fe / Mg bimetallic supported NS-doped biochar.

[0021] This embodiment provides a method for preparing a microbial fertilizer that degrades soil organic pesticides, specifically including the following steps: S1. After activating 1.0 g of MR-1 strain, it was inoculated into LB liquid medium. MR-1 strain was purchased from the China Center for Type Culture Collection (CCTCCAB2013238). MR-1 can reduce heavy metals or organic pollutants and promote their degradation through c-type cytochrome-mediated electron transfer. It can also secrete hydrolases and dehalogenases to participate in the desulfurization and dechlorination reactions of organic pesticides, thereby effectively degrading pesticide residues in the soil. The inoculation amount was 1% of the volume of LB liquid medium. The culture was carried out in a shaking incubator at 26℃ and 160 rpm for 12 h. After centrifugation, the collected bacterial cells were washed twice with inorganic salt liquid medium, and then the bacterial resuspended in sterile water to adjust the bacterial concentration to 2 × 10⁻⁶. 8 The process yielded highly active and environmentally adaptable MR-1 bacterial cells at CFU / mL, which can better enhance soil fertility by activating nutrients, regulating the microbial community, and improving the soil redox state, thus positively impacting crop growth, development, and yield. S2. Add 1.0g of sodium alginate to 100mL of water at 60℃ and stir for 20min. After cooling to 30℃, add 1.0g of sodium lactate. Sodium lactate acts as an isotonic regulator to improve the hypertonic environment generated during cross-linking, prevent the lysis of MR-1 bacterial cells, and provide energy and metabolic substrates for the growth of MR-1 bacteria. Sodium lactate can also form a glassy matrix during freeze-drying, reducing mechanical damage to the MR-1 cell membrane caused by ice crystals. Stir for 5min, then mix evenly with the MR-1 bacterial solution described in step S1. Add the mixture dropwise to the surface of Fe / Mg bimetallic supported NS-doped biochar using a syringe pump at a rate of 0.5mL / min. Let stand for 5min to fully impregnate the surface, incubate under anaerobic conditions at room temperature for 2h, and then immerse in 100mL of water. In a 1% calcium chloride solution, the cross-linking reaction was carried out for 10 min. The mixture was then removed, washed three times with sterile PBS solution, and freeze-dried. The MR-1 cells were tightly attached to the pores of the Fe / Mg bimetallic supported NS-doped biochar through a protective layer of sodium alginate-calcium chloride. This reduced the influence of adverse conditions such as pH and temperature in the soil on the activity of the cells, increased the loading and activity of the bacterial community, and facilitated the synergistic degradation of organic pesticides by the cells and the material. This significantly improved the effectiveness and efficiency of the degradation. The gel layer maintained suitable humidity and low oxygen conditions, which met the anaerobic metabolic requirements of MR-1. The gel layer delayed the diffusion of H2O2 and prolonged the action time of reactive oxygen species, which helped to improve the pesticide degradation efficiency. Thus, the Fe / Mg bimetallic NS-doped biochar composite material loaded with MR-1 was obtained. S3. After fermenting chicken manure at 50℃ for 5 days, the pre-fermented chicken manure, bentonite, and the MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material described in step S2 are mixed evenly at a speed of 15 rpm for 3 minutes. Controlling the mixing speed at a low speed can reduce the risk of material breakage and ensure the survival rate of the microorganisms. The MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material not only adsorbs multi-effect nutrients through its porous and gel structures, reducing nutrient loss and improving soil water retention and aeration, thereby increasing fertilizer utilization, but also exerts the nitrogen fixation, phosphorus solubilization, and plant growth promotion effects of MR-1. Furthermore, after eliminating the inhibitory effect of pesticides on fertilizer efficiency, it also enhances soil phosphatase activity, which is conducive to improving soil fertility and increasing crop yield and income, thus obtaining a microbial fertilizer that degrades soil organic pesticides. Example

[0022] This embodiment proposes a microbial fertilizer for degrading soil organic pesticides, comprising the following components in parts by weight: 55 parts Fe / Mg bimetallic supported NS-doped biochar, 2 parts MR-1 strain, 12.5 parts sodium lactate, 15 parts sodium alginate, 15 parts calcium chloride, 35 parts chicken manure, and 15 parts bentonite.

[0023] Fe / Mg bimetallic supported NS-doped biochar comprises the following components in parts by weight: 25 parts NS co-doped biochar, 15 parts ferric chloride hexahydrate, 7.5 parts magnesium chloride hexahydrate, 2 parts calcium peroxide, 7.5 parts humic acid, and 0.75 parts cetyltrimethylammonium bromide.

[0024] The preparation method of Fe / Mg bimetallic supported NS-doped biochar includes the following steps: (1) The municipal sludge was dried in an oven at 75℃ for 24 hours, pulverized by a grinder and passed through a 100-mesh sieve. 25.0g of sludge powder was weighed and mixed with 12.5g of ammonium persulfate. 300mL of deionized water was added and the mixture was continuously stirred at 60℃ for 21 hours under sealed conditions. The mixture was then transferred to an oven at 85℃ for 48 hours to dry completely. After dehydration, it was ground and dispersed and placed in a ceramic boat. Nitrogen gas was introduced into the tube furnace for protection, and the mixture was pyrolyzed at 290℃ for 1.5 hours. The porous structure and high specific surface area of ​​biochar can adsorb pesticides such as organochlorine and organophosphorus in the soil, reduce their migration and bioavailability, and indirectly promote degradation. At the same time, N and S functional groups can catalyze the decomposition of pesticides through surface redox reactions or generate active oxygen to participate in degradation. Biochar also provides habitat and nutrient supply for microorganisms, promotes their growth and accelerates the biodegradation of organic pesticides. In addition, biochar can also regulate the pH, water retention and aeration of the soil, optimize the living conditions of microorganisms, and obtain NS co-doped biochar. (2) The NS co-doped biochar described in step (1) is first dispersed in 300 mL of deionized water, and then humic acid and hexadecyltrimethylammonium bromide are added. The amount of humic acid added is 0.75 g. As a natural oxidant, humic acid can form a complex with Fe / Mg, improve the dispersibility of the metal, reduce the risk of metal leaching, and can also adsorb organic pesticides through its own hydrophobic effect, enriching them at the Fe / Mg active sites and increasing the local reaction concentration. The amount of hexadecyltrimethylammonium bromide added is 0.075 g. The cation of hexadecyltrimethylammonium bromide is... Ions are adsorbed onto the surface of biochar via electrostatic interactions, with long-chain alkyl groups aligning outwards to form a hydrophobic layer. This effectively improves the adsorption of non-polar pesticides by the biochar. Furthermore, the hydrophobic-hydrophobic interaction between the alkyl chain of hexadecyltrimethylammonium bromide and the benzene ring of the pesticide further enhances the adsorption capacity. The mixture is stirred for 7.5 min, ultrasonically treated for 25 min, and then 1.5 g of ferric chloride hexahydrate and 0.75 g of magnesium chloride hexahydrate are added. The mixture is placed in a 55°C thermostatically heated magnetic stirrer, and an equal volume fraction of 2.5 g of ferric chloride hexahydrate is slowly added dropwise. A % citric acid solution was prepared and stirred continuously for 150 min. The temperature was then raised to 85℃, and stirring continued until the solution concentrated and transformed into a gel. 0.2 g of calcium peroxide was mixed with the gel and ground. The mixture was then dried in a 90℃ oven for 11 h. After crushing, grinding, and sieving through a 150-mesh sieve, the mixture was finally transferred to a ceramic boat and placed in a tube furnace under nitrogen protection. The temperature was first raised to 300℃ at a rate of 5℃ / min, then to 675℃, and pyrolyzed for 1.5 h. In this process, Fe / Mg oxide nanoparticles were uniformly dispersed in the N-S co-doped solution. In the mesopores of biochar, humic acid carbonization retains oxygen-containing functional groups, distributed at the edges of the biochar framework. Calcium peroxide is partially converted into calcium carbonate microcrystals, dispersed within the biochar pores, serving as a slow-release source of H2O2 to ensure the Fenton-like reaction. After pyrolysis, hexadecyltrimethylammonium bromide leaves a hydrophobic carbon layer that covers part of the Fe / Mg oxide nanoparticle surface, thus forming a stable hierarchical porous structure. This provides more adsorption-catalytic sites, significantly improving the degradation efficiency of both water-soluble and fat-soluble pesticides. Fe provides catalytically active sites, through which Fe... 3+ / Fe 2+ Mg participates in the Fenton-like reaction, activating peroxides and H2O2 in the soil to generate reactive oxygen species, which directly oxidize organic pesticides. Mg not only enhances structural stability and regulates surface charge, but also promotes electron transfer and buffers soil pH, ensuring the Fenton-like reaction remains effective within a pH range of 5-8. The quinone groups of humic acid can accept / donate electrons, accelerating the reduction to Fe. 2+The process promotes the continuous generation of reactive oxygen species. Hexadecyltrimethylammonium bromide forms micelles in solution, which can serve as templates for the growth of nano-Fe / Mg oxides, preventing metal aggregation and increasing the exposure rate of active sites. The hydrophobic surface modified with hexadecyltrimethylammonium bromide can accelerate the transfer of electrons from biochar to adsorbed pesticides, enhancing the Fe... 3+ / Fe 2+ The recycling efficiency was improved to obtain Fe / Mg bimetallic supported NS-doped biochar.

[0025] This embodiment provides a method for preparing a microbial fertilizer that degrades soil organic pesticides, specifically including the following steps: S1. After activating 2.0g of MR-1 strain, it was inoculated into LB liquid medium. MR-1 strain was purchased from the China Center for Type Culture Collection (CCTCCAB2013238). MR-1 can reduce heavy metals or organic pollutants and promote their degradation through c-type cytochrome-mediated electron transfer. It can also secrete hydrolases and dehalogenases to participate in the desulfurization and dechlorination reactions of organic pesticides, thereby effectively degrading pesticide residues in the soil. The inoculation amount was 2% of the volume of LB liquid medium. The culture was carried out in a shaking incubator at 28℃ and 170rpm for 12h. After centrifugation, the collected bacterial cells were washed twice with inorganic salt liquid medium, and then the bacterial cells were resuspended in sterile water to adjust the bacterial concentration to 2×10⁻⁶. 8 The process yielded highly active and environmentally adaptable MR-1 bacterial cells at CFU / mL, which can better enhance soil fertility by activating nutrients, regulating the microbial community, and improving the soil redox state, thus positively impacting crop growth, development, and yield. S2. Add 1.5g of sodium alginate to 100mL of water at 65℃, stir for 25min, cool to 32.5℃, and then add 1.25g of sodium lactate. Sodium lactate acts as an isotonic regulator to improve the hypertonic environment generated during cross-linking, prevent the lysis of MR-1 bacterial cells, and provide energy and metabolic substrates for the growth of MR-1 bacteria. Sodium lactate can also form a glassy matrix during freeze-drying, reducing mechanical damage to the MR-1 cell membrane caused by ice crystals. Stir for 7.5min, then mix evenly with the MR-1 bacterial solution described in step S1. Add the mixture dropwise to the surface of Fe / Mg bimetallic supported NS-doped biochar using a syringe pump at a rate of 0.75mL / min. Let stand for 7.5min to fully impregnate, incubate under anaerobic conditions at room temperature for 3h, and then immerse in 100mL of water. In a 1.5% (w / w) calcium chloride solution, the cross-linking reaction was carried out for 12.5 min. The mixture was then removed, washed four times with sterile PBS solution, and freeze-dried. The MR-1 cells were tightly attached to the pores of the Fe / Mg bimetallic-supported NS-doped biochar through a protective layer of sodium alginate-calcium chloride. This reduced the impact of adverse conditions such as pH and temperature in the soil on the activity of the cells, increased the loading and activity of the bacterial community, and facilitated the synergistic degradation of organic pesticides by the cells and the material. This significantly improved the effectiveness and efficiency of the degradation. The gel layer maintained suitable humidity and low oxygen conditions, which met the anaerobic metabolic requirements of MR-1. The gel layer delayed the diffusion of H2O2 and prolonged the action time of reactive oxygen species, which helped to improve the pesticide degradation efficiency. Thus, the Fe / Mg bimetallic NS-doped biochar composite material loaded with MR-1 was obtained. S3. After fermenting chicken manure at 52.5℃ for 6 days, the pre-fermented chicken manure, bentonite, and the MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material described in step S2 are mixed evenly at a speed of 18 rpm for 4 minutes. Controlling the mixing speed at a low speed reduces the risk of material breakage and ensures the survival rate of the microorganisms. The MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material not only adsorbs multi-effect nutrients through its porous and gel structures, reducing nutrient loss and improving soil water retention and aeration, thereby increasing fertilizer utilization, but also exerts the nitrogen-fixing, phosphorus-solubilizing, and plant growth-promoting effects of MR-1. Furthermore, after eliminating the inhibitory effect of pesticides on fertilizer efficiency, it also enhances soil phosphatase activity, which is beneficial to improving soil fertility and increasing crop yield and income, thus obtaining a microbial fertilizer that degrades soil organic pesticides. Example

[0026] This embodiment proposes a microbial fertilizer for degrading soil organic pesticides, comprising the following components in parts by weight: 50 parts Fe / Mg bimetallic supported NS-doped biochar, 3 parts MR-1 strain, 10 parts sodium lactate, 20 parts sodium alginate, 10 parts calcium chloride, 40 parts chicken manure, and 20 parts bentonite.

[0027] Fe / Mg bimetallic supported NS-doped biochar comprises the following components in parts by weight: 30 parts NS co-doped biochar, 20 parts ferric chloride hexahydrate, 5 parts magnesium chloride hexahydrate, 3 parts calcium peroxide, 5 parts humic acid, and 0.5 parts cetyltrimethylammonium bromide.

[0028] The preparation method of Fe / Mg bimetallic supported NS-doped biochar includes the following steps: (1) The municipal sludge was dried in an 80℃ oven for 24 hours, pulverized by a grinder and passed through a 100-mesh sieve. 30.0g of sludge powder was weighed and mixed with 15.0g of ammonium persulfate. 300mL of deionized water was added and the mixture was continuously stirred at 60℃ for 18 hours under sealed conditions. The mixture was then transferred to a 90℃ oven for 48 hours to dry completely. After dehydration, it was ground and dispersed and placed in a ceramic boat. Nitrogen gas was introduced into the tube furnace for protection, and the mixture was pyrolyzed at 300℃ for 1 hour. The porous structure and high specific surface area of ​​biochar can adsorb pesticides such as organochlorine and organophosphorus in the soil, reduce their migration and bioavailability, and indirectly promote degradation. At the same time, N and S functional groups can catalyze the decomposition of pesticides through surface redox reactions or generate active oxygen to participate in degradation. Biochar also provides habitat and nutrient supply for microorganisms, promotes their growth and accelerates the biodegradation of organic pesticides. In addition, biochar can also regulate the pH, water retention and aeration of the soil, optimize the living conditions of microorganisms, and obtain NS co-doped biochar. (2) The NS co-doped biochar described in step (1) is first dispersed in 300 mL of deionized water, and then humic acid and hexadecyltrimethylammonium bromide are added. The amount of humic acid added is 0.5 g. As a natural oxidant, humic acid can form a complex with Fe / Mg, improve the dispersibility of the metal, reduce the risk of metal leaching, and can also adsorb organic pesticides through its own hydrophobic effect, enriching them at the Fe / Mg active sites and increasing the local reaction concentration. The amount of hexadecyltrimethylammonium bromide added is 0.05 g. The cation of hexadecyltrimethylammonium bromide is... Ions are adsorbed onto the surface of biochar via electrostatic interactions, with long-chain alkyl groups aligning outwards to form a hydrophobic layer. This effectively improves the adsorption of non-polar pesticides by biochar. Furthermore, the hydrophobic-hydrophobic interaction between the alkyl chain of hexadecyltrimethylammonium bromide and the benzene ring of the pesticide further enhances the adsorption capacity. The mixture is stirred for 5 minutes, ultrasonically treated for 20 minutes, and then 2.0 g of ferric chloride hexahydrate and 0.5 g of magnesium chloride hexahydrate are added. The mixture is placed in a 60°C thermostatically heated magnetic stirrer, and an equal volume of 3% (by mass) of [a specific ingredient / component] is slowly added dropwise. A citric acid solution was continuously stirred for 120 minutes, then the temperature was raised to 90°C, and stirring continued until the solution concentrated and turned into a gel. 0.3 g of calcium peroxide was mixed with the gel and ground, then transferred to a 90°C oven to dry for 10 hours. After crushing, grinding, and sieving through a 200-mesh sieve, the mixture was finally transferred to a ceramic boat and placed in a tube furnace under nitrogen protection. The temperature was first raised to 300°C at a rate of 5°C / min, then to 700°C, and pyrolyzed for 1 hour. In this process, Fe / Mg oxide nanoparticles were uniformly dispersed in the NS co-doped biofilm. In the mesopores of biochar, humic acid, after carbonization, retains oxygen-containing functional groups distributed at the edges of the biochar framework. Calcium peroxide is partially converted into calcium carbonate microcrystals, dispersed within the biochar pores, serving as a slow-release source of H2O2 to ensure the Fenton-like reaction. After pyrolysis, hexadecyltrimethylammonium bromide leaves a hydrophobic carbon layer that covers part of the Fe / Mg oxide nanoparticle surface, thus forming a stable hierarchical porous structure. This provides more adsorption-catalytic sites, significantly improving the degradation efficiency of both water-soluble and fat-soluble pesticides. Fe provides catalytically active sites, through which Fe... 3+ / Fe 2+ Mg participates in the Fenton-like reaction, activating peroxides and H2O2 in the soil to generate reactive oxygen species, which directly oxidize organic pesticides. Mg not only enhances structural stability and regulates surface charge, but also promotes electron transfer and buffers soil pH, ensuring the Fenton-like reaction remains effective within a pH range of 5-8. The quinone groups of humic acid can accept / donate electrons, accelerating the reduction to Fe. 2+The process promotes the continuous generation of reactive oxygen species. Hexadecyltrimethylammonium bromide forms micelles in solution, which can serve as templates for the growth of nano-Fe / Mg oxides, preventing metal aggregation and increasing the exposure rate of active sites. The hydrophobic surface modified with hexadecyltrimethylammonium bromide can accelerate the transfer of electrons from biochar to adsorbed pesticides, enhancing the Fe... 3+ / Fe 2+ The recycling efficiency was improved to obtain Fe / Mg bimetallic supported NS-doped biochar.

[0029] This embodiment provides a method for preparing a microbial fertilizer that degrades soil organic pesticides, specifically including the following steps: S1. After activating 3.0g of MR-1 strain, it was inoculated into LB liquid medium. MR-1 strain was purchased from the China Center for Type Culture Collection (CCTCCAB2013238). MR-1 can reduce heavy metals or organic pollutants and promote their degradation through c-type cytochrome-mediated electron transfer. It can also secrete hydrolases and dehalogenases to participate in the desulfurization and dechlorination reactions of organic pesticides, thereby effectively degrading pesticide residues in the soil. The inoculation amount was 1% of the volume of LB liquid medium. The culture was carried out in a shaking incubator at 30℃ and 180rpm for 12h. After centrifugation, the collected bacterial cells were washed twice with inorganic salt liquid medium, and then the bacterial resuspended in sterile water to adjust the bacterial concentration to 2×10⁻⁶. 8 The process yielded highly active and environmentally adaptable MR-1 bacterial cells at CFU / mL, which can better enhance soil fertility by activating nutrients, regulating the microbial community, and improving the soil redox state, thus positively impacting crop growth, development, and yield. S2. Add 2.0g of sodium alginate to 100mL of water at 70℃ and stir for 20min. After cooling to 35℃, add 1.0g of sodium lactate. Sodium lactate acts as an isotonic regulator to improve the hypertonic environment generated during cross-linking, prevent the lysis of MR-1 bacterial cells, and provide energy and metabolic substrates for the growth of MR-1 bacteria. Sodium lactate can also form a glassy matrix during freeze-drying, reducing mechanical damage to the MR-1 cell membrane caused by ice crystals. Stir for 5min, then mix evenly with the MR-1 bacterial solution described in step S1. Add the mixture dropwise to the surface of Fe / Mg bimetallic supported NS-doped biochar using a syringe pump at a rate of 1mL / min. Let stand for 5min to fully impregnate the surface, incubate under anaerobic conditions at room temperature for 2h, and then immerse in 100mL of water. In a 1% calcium chloride solution, the cross-linking reaction was carried out for 10 min. The mixture was then removed, washed five times with sterile PBS solution, and freeze-dried. The MR-1 cells were tightly attached to the pores of the Fe / Mg bimetallic supported NS-doped biochar through a protective layer of sodium alginate-calcium chloride. This reduced the impact of adverse conditions such as pH and temperature in the soil on the activity of the cells, increased the loading and activity of the bacterial community, and facilitated the synergistic degradation of organic pesticides by the cells and the material. This significantly improved the effectiveness and efficiency of the degradation. The gel layer maintained suitable humidity and low oxygen conditions, which met the anaerobic metabolic requirements of MR-1. The gel layer delayed the diffusion of H2O2 and prolonged the action time of reactive oxygen species, which helped to improve the pesticide degradation efficiency. Thus, the Fe / Mg bimetallic NS-doped biochar composite material loaded with MR-1 was obtained. S3. After fermenting chicken manure at 55℃ for 5 days, the pre-fermented chicken manure, bentonite, and the MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material described in step S2 are mixed evenly at a speed of 20 rpm for 3 minutes. Controlling the mixing speed at a low speed can reduce the risk of material breakage and ensure the survival rate of the microorganisms. The MR-1-loaded Fe / Mg bimetallic NS-doped biochar composite material not only adsorbs multi-effect nutrients through its porous and gel structures, reducing nutrient loss and improving soil water retention and aeration, thereby increasing fertilizer utilization, but also exerts the nitrogen fixation, phosphorus solubilization, and plant growth promotion effects of MR-1. Furthermore, after eliminating the inhibitory effect of pesticides on fertilizer efficiency, it also enhances soil phosphatase activity, which is conducive to improving soil fertility and increasing crop yield and income, thus obtaining a microbial fertilizer that degrades soil organic pesticides.

[0030] Comparative Example 1 This comparative example provides a microbial fertilizer for degrading soil organic pesticides. The difference between this and Example 1 is that the Fe / Mg bimetallic supported NS-doped biochar does not contain ferric chloride hexahydrate or magnesium chloride hexahydrate; ferric chloride hexahydrate or magnesium chloride hexahydrate is not added in step (2) of the preparation method of Fe / Mg bimetallic supported NS-doped biochar; and the preparation method of the microbial fertilizer for degrading soil organic pesticides is the same as that of Example 1.

[0031] Comparative Example 2 This comparative example provides a microbial fertilizer for degrading soil organic pesticides. The difference between this and Example 1 is that the Fe / Mg bimetallic supported NS-doped biochar does not contain humic acid; humic acid is not added in step (2) of the preparation method of Fe / Mg bimetallic supported NS-doped biochar; and the preparation method of the microbial fertilizer for degrading soil organic pesticides is the same as that of Example 1.

[0032] Comparative Example 3 This comparative example provides a microbial fertilizer for degrading soil organic pesticides. The difference between this and Example 1 is that the Fe / Mg bimetallic supported NS-doped biochar does not contain hexadecyltrimethylammonium bromide; hexadecyltrimethylammonium bromide is not added in step (2) of the preparation method of Fe / Mg bimetallic supported NS-doped biochar; and the preparation method of the microbial fertilizer for degrading soil organic pesticides is the same as that of Example 1.

[0033] Comparative Example 4 This comparative example provides a microbial fertilizer for degrading soil organic pesticides. The difference between this microbial fertilizer and Example 1 is that the microbial fertilizer for degrading soil organic pesticides does not contain sodium alginate or calcium chloride; the preparation method of Fe / Mg bimetallic supported NS-doped biochar is the same as in Example 1; sodium alginate is not added and calcium chloride solution is not immersed in step S2 of the preparation method of the microbial fertilizer for degrading soil organic pesticides.

[0034] Experimental Example 1 Bacterial cell activity test Test samples: Microbial fertilizers for degrading soil organic pesticides prepared in Examples 1-4 and Comparative Examples 1-4.

[0035] Test method: Weigh 0.1g of organic pesticide (DDT as an example) and dissolve it in 200mL of a mixed solvent of acetone and n-hexane (volume ratio 1:1). Mix it evenly with 1kg of basic soil (soil pH 5.5-6.5, moisture content 25±3%) (protected from light). After the solvent evaporates, age for 7 days to prepare simulated soil. Take 10g of sample from the simulated soil, weigh 1.0g of test sample and add it to the soil. Shake and incubate for 12h at 30℃ and 120rpm. Take 0.5g of soil sample and perform serial dilution with PBS buffer and determine the number of viable bacteria in the soil (LogCFU / g).

[0036] Figure 2 The figures show the viable cell counts for Examples 1-4 and Comparative Examples 1-4. As shown, the viable cell counts for Examples 1-4 were 7.7-8.3 LogCFU / g, indicating strong bacterial activity; the viable cell counts for Comparative Examples 1-4 were 6.5-7.3 LogCFU / g, indicating weaker bacterial activity. The Fe / Mg bimetallic supported NS-doped biochar of Comparative Example 1 lacked ferric chloride hexahydrate and magnesium chloride hexahydrate, thus failing to act as electron acceptors to support the anaerobic respiratory chain of the bacteria, hindering the maintenance of bacterial metabolic activity, and also failing to neutralize soil acidity, increasing the risk of bacterial inactivation at low pH, resulting in weaker bacterial activity. The Fe / Mg bimetallic supported NS-doped biochar of Comparative Example 2 lacked humic acid, which is detrimental to the chelation of F... The e / Mg forms a slow-release complex, which cannot provide a continuous supply of iron and magnesium nutrients, nor can it directly provide membrane protection. This is not conducive to reducing direct damage to the bacteria from the external environment, resulting in weak bacterial activity. The Fe / Mg bimetallic supported NS-doped biochar in Comparative Example 3 does not contain cetyltrimethylammonium bromide, which is not conducive to promoting the uniform dispersion of Fe / Mg oxide nanoparticles. Therefore, it cannot ensure the maximization of the contact area when the bacteria are loaded, nor can it reduce the adverse effects of water by forming hydrophobic microregions, resulting in weak bacterial activity. The microbial fertilizer for degrading soil organic pesticides in Comparative Example 4 does not contain sodium alginate and calcium chloride, which cannot form a gel coating protective layer. This does not meet the anaerobic metabolic requirements of MR-1, resulting in weak bacterial activity.

[0037] Experimental Example 2 Pesticide degradation experiment Test samples: Microbial fertilizers for degrading soil organic pesticides prepared in Examples 1-4 and Comparative Examples 1-4.

[0038] Test method: Weigh 0.1g of organic pesticide (DDT as an example) and dissolve it in 200mL of a mixed solvent of acetone and n-hexane (volume ratio 1:1). Mix the solution with 1kg of basic soil (soil pH 5.5-7.5, moisture content 25±3%) and ensure uniform mixing (protected from light). After solvent evaporation, age the soil for 7 days to prepare simulated soil. Take 10g of the simulated soil sample and add 1.0g of the test sample to each sample as the experimental group. The soil without the test sample is the control group, and the soil without pesticide is the blank group. After 14 days, use acetonitrile for ultrasonic extraction and HPLC to detect the residual concentration (chromatographic column: C18 reversed-phase column, mobile phase: methanol-water 80:20, detection wavelength: 220nm). Calculate the degradation rate (%) according to the following formula: Degradation rate (%) = [1 - (C)] 实验 -C 空白 ) / (C 对照- C 空白 )]×100%.

[0039] Figure 3 The figures show the degradation rate results for Examples 1-4 and Comparative Examples 1-4. As shown, the degradation rate for Examples 1-4 was 70-78%, indicating better pesticide degradation. The degradation rate for Comparative Examples 1-4 was 56-66%, indicating moderate pesticide degradation. The Fe / Mg bimetallic supported NS-doped biochar in Comparative Example 1 lacked ferric chloride hexahydrate and magnesium chloride hexahydrate, thus failing to maintain the pH environment to optimize the Fenton-like reaction efficiency. Consequently, it could not oxidize and decompose organic pesticides, relying solely on microbial decomposition, resulting in moderate pesticide degradation. The Fe / Mg bimetallic supported NS-doped biochar in Comparative Example 2 lacked humic acid, preventing the acceleration of Fe degradation through electron penetrating bodies. 3+ / Fe 2+ The lack of cetyltrimethylammonium bromide in the Fe / Mg bimetallic supported NS-doped biochar of Comparative Example 3 is detrimethylammonium bromide, which is not conducive to increasing the exposure of active sites, reducing the adsorption of pesticides, and is not conducive to the degradation of pesticides by materials and microorganisms, resulting in general pesticide degradation performance. The lack of sodium alginate and calcium chloride in the microbial fertilizer for degrading soil organic pesticides in Comparative Example 4 is detrimental to the formation of a gel layer, which is not conducive to delaying the diffusion of H2O2 and shortening the action time of reactive oxygen species, resulting in general pesticide degradation performance.

[0040] Experimental Example 3 Crop yield increase experiment Test samples: Microbial fertilizers for degrading soil organic pesticides prepared in Examples 1-4 and Comparative Examples 1-4.

[0041] Test Method: Eight small, uniformly sized rice demonstration plots in Tianjin were selected for the experiment, with the soil organic pesticide content set at 2.0 mg / kg. Seven of these plots used test samples, with fertilizer applied at a rate of 30 kg / mu every 10 days. Rice from the plots using conventional fertilizer served as a control. After the rice plants in each experimental plot completed their vegetative growth phase, 20 rice plants were randomly selected, and the number of grains per panicle was recorded and averaged. The yield increase rate (%) was calculated using the following formula: Yield increase rate (%) = (number of grains per ear of test sample - number of grains per ear of control) / number of grains per ear of control × 100%.

[0042] Figure 4The figures show the yield increase rates of Examples 1-4 and Comparative Examples 1-4. As shown, the yield increase rate of Examples 1-4 was 13.7-15.2%, indicating a good yield increase effect; the yield increase rate of Comparative Examples 1-4 was 7.2-10.6%, indicating a poor yield increase effect. The Fe / Mg bimetallic supported NS-doped biochar of Comparative Example 1 did not contain ferric chloride hexahydrate or magnesium chloride hexahydrate, thus failing to degrade organic pesticide residues and negatively impacting crops. Furthermore, it could not provide the necessary Fe / Mg nutrients for crop growth, resulting in a poor yield increase effect. The Fe / Mg bimetallic supported NS-doped biochar of Comparative Example 2 did not contain humic acid, which is detrimental to adsorption. Nutrient ions increase nutrient loss and cannot eliminate the adverse effects of residual organic pesticides on crops, resulting in poor yield increase. The Fe / Mg bimetallic supported NS-doped biochar in Comparative Example 3 does not contain hexadecyltrimethylammonium bromide, which is not conducive to slowing down the dissolution rate of water-soluble nutrients, increasing the risk of loss. At the same time, it reduces the degradation efficiency of organic pesticides in the soil, which is not conducive to crop growth, resulting in poor yield increase. The microbial fertilizer for degrading soil organic pesticides in Comparative Example 4 does not contain sodium alginate and calcium chloride, which cannot improve the soil's water retention and aeration through the gel structure, reducing fertilizer utilization and resulting in poor yield increase.

[0043] The above experimental results show that the bacterial cell activity, pesticide degradation, and crop yield increase of Examples 1-4 of the present invention are significantly better than those of Comparative Examples 1-4. Among them, Example 1, which uses Fe / Mg bimetallic NS-doped biochar composite material loaded with MR-1, has stronger bacterial cell activity, better pesticide degradation, and better crop yield increase. Attaching MR-1 bacterial solution to the pores of Fe / Mg bimetallic loaded NS-doped biochar and then encapsulating and protecting it with a gel layer formed by sodium alginate and calcium chloride improves the loading stability, loading amount, and activity of the bacterial community. Furthermore, the synergistic assembly of MR-1 bacterial cells and biochar-based materials on organic pesticides significantly improves the effectiveness and efficiency of degradation, eliminates the adverse effects of pesticides, and is beneficial to increasing crop yield and income.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

[0045] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A microbial fertilizer for degrading soil organic pesticides, characterized in that: The microbial fertilizer for degrading soil organic pesticides comprises the following components in parts by weight: 50-60 parts Fe / Mg bimetallic supported NS-doped biochar, 1-3 parts MR-1 strain, 10-15 parts sodium lactate, 10-20 parts sodium alginate, 10-20 parts calcium chloride, 30-40 parts chicken manure, and 10-20 parts bentonite; the Fe / Mg bimetallic supported NS-doped biochar comprises the following components in parts by weight: 20-30 parts NS co-doped biochar, 10-20 parts ferric chloride hexahydrate, 5-10 parts magnesium chloride hexahydrate, 1-3 parts calcium peroxide, 5-10 parts humic acid, and 0.5-1 parts hexadecyltrimethylammonium bromide; the MR-1 strain was purchased from the China Center for Type Culture Collection, with the number CCTCAB2013238. The preparation method of the Fe / Mg bimetallic supported NS-doped biochar specifically includes the following steps: (1) Place municipal sludge in an oven at 70-80℃ and dry for 24 hours. After grinding with a grinder, pass through a 100-mesh sieve. Weigh 20.0-30.0g of sludge powder and mix it evenly with 10.0-15.0g of ammonium persulfate. Add 300mL of deionized water and stir continuously at 60℃ for 18-24 hours under sealed conditions. Then transfer the mixture to an oven at 80-90℃ and dry for 48 hours. After complete dehydration, grind and disperse the mixture. Place it in a ceramic boat and purge it with nitrogen in a tube furnace. Pyrolyze it at 280-300℃ for 1-2 hours to obtain NS co-doped biochar. (2) First, disperse the NS co-doped biochar described in step (1) in 300 mL of deionized water, then add humic acid and hexadecyltrimethylammonium bromide, stir together for 5-10 min, sonicate for 20-30 min, then add 1.0-2.0 g of ferric chloride hexahydrate and 0.5-1.0 g of magnesium chloride hexahydrate. Place the mixed liquid in a heat-collecting constant-temperature magnetic stirrer at 50-60℃, and slowly add an equal volume of 2-3% citric acid solution, stirring continuously for 120-180 min. The temperature was then raised to 80-90℃, and stirring continued until the solution was concentrated and turned into a gel. 0.1-0.3g of calcium peroxide was mixed with the gel and ground. The mixture was then transferred to a 90℃ oven and dried for 10-12 hours. After crushing, grinding, and sieving through a 100-200 mesh sieve, the mixture was finally transferred to a ceramic boat and placed in a tube furnace. Nitrogen gas was introduced for protection, and the temperature was raised to 300℃ at a rate of 5℃ / min, and then raised to 650-700℃ for pyrolysis for 1-2 hours to obtain Fe / Mg bimetallic supported NS-doped biochar.

2. A method for preparing a microbial fertilizer for degrading soil organic pesticides according to claim 1, characterized in that: Specifically, the following steps are included: S1. After activating 1.0-3.0 g of MR-1 strain, inoculate it into LB liquid medium at a volume of 1-3% of the LB liquid medium. Incubate at 26-30℃ and 160-180 rpm for 12 h. Centrifuge and wash the collected bacterial cells twice with inorganic salt liquid medium. Then resuspend the bacterial cells in sterile water and adjust the bacterial concentration to 2×10⁻⁶. 8 CFU / mL was used to obtain MR-1 bacterial culture; S2. Add 1.0-2.0g of sodium alginate to 100mL of water at 60-70℃ and stir for 20-30min. After cooling to 30-35℃, add sodium lactate and stir for 5-10min. Then mix it evenly with the MR-1 bacterial solution mentioned in step S1. Add it dropwise to the surface of Fe / Mg bimetallic supported NS-doped biochar using a syringe pump at a rate of 0.5-1mL / min. Let it stand for 5-10min to fully impregnate it. Incubate it under anaerobic conditions at room temperature for 2-4h. Then immerse it in 100mL of calcium chloride solution with a mass fraction of 1-2% and crosslink it for 10-15min. Take it out and wash it 3-5 times with sterile PBS solution. Freeze-dry it to obtain the MR-1 supported Fe / Mg bimetallic NS-doped biochar composite material. S3. After fermenting chicken manure at 50-55℃ for 5-7 days, the pre-fermented chicken manure, bentonite, and the Fe / Mg bimetallic NS-doped biochar composite material loaded with MR-1 described in step S2 are mixed evenly to obtain a microbial fertilizer that degrades soil organic pesticides.

3. The method for preparing microbial fertilizer for degrading soil organic pesticides according to claim 2, characterized in that: In step S2, the amount of sodium lactate added is 1.0-1.5g.

4. The method for preparing microbial fertilizer for degrading soil organic pesticides according to claim 3, characterized in that: In step S3, the mixing speed is 15-20 rpm and the mixing time is 3-5 min.

5. The method for preparing microbial fertilizer for degrading soil organic pesticides according to claim 4, characterized in that: In step (2), the amount of humic acid added is 0.5-1.0g; the amount of hexadecyltrimethylammonium bromide added is 0.05-0.1g.

Images