Method for degrading straw by graphene synergistic low-temperature bacterial agent

Abstract

This invention discloses a method for degrading straw using a graphene-enhanced low-temperature microbial agent, comprising the following steps: (1) crushing the straw on-site using a straw crusher; (2) spraying an aqueous dispersion of graphene oxide using a sprayer; (3) spraying an aqueous dispersion of the low-temperature microbial agent using a sprayer; (4) plowing and covering the straw with soil to a depth of 20-40 cm using a rotary tiller. This invention features energy saving, high efficiency, and environmental protection. The optimized low-temperature microbial agent does not require heating and degrades directly at low temperatures; graphene is selected to avoid toxicity to soil microorganisms, and its high specific surface area can provide more attachment sites for microorganisms. Its good electrical and thermal conductivity can promote the metabolic activities of microorganisms, and the degradation rate is significantly improved compared with traditional microbial agents; while utilizing straw resources, it reduces PM2.5 emissions caused by straw burning.

Description

Technical Field

[0001] This invention belongs to the field of solid waste treatment technology, specifically relating to a method for degrading straw using a graphene-enhanced low-temperature microbial agent. Background Technology

[0002] As an agricultural byproduct, straw plays a crucial role in environmental protection and sustainable agricultural development through resource utilization. However, due to its high content of cellulose, hemicellulose, and lignin, and its complex structure, straw is difficult for microorganisms to decompose, resulting in generally low degradation efficiency. Traditional methods, such as burning corn straw, not only pollute the environment but also easily cause fires; using it as livestock feed is also difficult to process large quantities of straw in a short time, which is detrimental to the development of my country's agricultural economy; while directly returning straw to the field, due to the slow natural decomposition process, can easily lead to soil structure deterioration, affecting crop root growth and nutrient absorption, thereby reducing crop yield and quality. Therefore, developing efficient and environmentally friendly straw degradation technologies has become a critical issue that urgently needs to be addressed in the process of sustainable agricultural development.

[0003] Currently, using microbial inoculants to degrade straw has become a highly regarded green and environmentally friendly method. However, ordinary inoculants have a significant limitation: their activity decreases drastically in low-temperature environments, greatly restricting degradation efficiency. In winter and other low-temperature seasons in northern my country, conventional inoculants are difficult to fully exert their effects, making it difficult to smoothly advance straw treatment and seriously hindering the efficiency of agricultural waste resource utilization.

[0004] Graphene is currently considered one of the most promising applications, serving as a silicon alternative in the manufacture of ultra-miniature transistors, ultimately leading to the production of future supercomputers. With its superior optical, electrical, and mechanical properties, graphene shows broad application prospects in materials science, micro-nano fabrication, energy, biomedicine, and drug delivery, earning it the reputation of a revolutionary future material. It is also hailed as the "king of new materials" and "black gold." Research has found that graphene materials, when infiltrated into soil, can influence the soil's microbial community. Summary of the Invention

[0005] To address the problem that the activity of microbial agents decreases significantly under low-temperature conditions, leading to a substantial reduction in the microbial degradation efficiency of straw in cold regions, this invention significantly improves the microbial degradation efficiency of straw at low temperatures through the optimization of microorganisms and the synergistic effect of graphene, making it particularly suitable for promotion in high-altitude and cold regions.

[0006] To achieve the above objectives, the following technical solution is adopted: A method for degrading straw using a graphene-enhanced low-temperature microbial agent includes the following steps: (1) Use a straw crusher to crush the straw on-site; (2) Spray the aqueous dispersion of graphene oxide using a sprayer; (3) Spray the aqueous dispersion of the low-temperature bacterial agent using a sprayer; (4) Use a rotary tiller to turn over and cover with soil to a depth of 20-40cm.

[0007] According to the above plan, step 1 involves crushing the straw to a length of 1-5 cm.

[0008] According to the above scheme, the graphene oxide in step 2 has a particle size ≤ 5 μm and a specific surface area > 500 m². 2 / g.

[0009] According to the above scheme, the concentration of the aqueous dispersion of graphene oxide in step 2 is 5-50 mg / L.

[0010] According to the above scheme, the amount of the aqueous dispersion of graphene oxide in step 2 is 6.18 × 10⁻⁶. -7 kg / mu - 6.18×10 -5 kg / mu.

[0011] According to the above scheme, the low-temperature microbial agent mentioned in step 3 is a low-temperature microorganism capable of degrading straw, specifically a microbial agent composed of Trichoderma and Fusarium oxysporum. In the optimized scheme, Trichoderma and Fusarium oxysporum are mixed in a 1:1 ratio.

[0012] According to the above scheme, the dosage of the low-temperature bacterial agent spraying in step 3 is 10. 15 cfu / acre.

[0013] According to the above scheme, step 4 also includes covering the ground with plastic film for insulation when extreme low temperatures below -30℃ occur; the optimized degradation temperature is 10℃~25℃.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses a straw crusher to crush straw to a length of 1-5 cm on-site, increasing the specific surface area to promote microbial attachment; and uses a graphene composite low-temperature microbial agent to improve the ability of the microbial agent to degrade straw.

[0015] This invention features energy saving, high efficiency, and environmental friendliness. The optimized low-temperature microbial agent requires no heating and degrades directly at low temperatures. Graphene (GO) is selected to avoid toxicity to soil microorganisms, while its high specific surface area provides more attachment sites for microorganisms. Its excellent electrical and thermal conductivity promotes microbial metabolic activity, resulting in a significantly faster degradation rate compared to traditional microbial agents. This invention also reduces PM2.5 emissions from straw burning while utilizing straw as a resource. Attached Figure Description

[0016] Figure 1 Total potassium content in soil in the examples and comparative examples. Detailed Implementation

[0017] The following embodiments further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0018] A specific embodiment provides a mixed low-temperature bacterial strain, specifically a 1:1 ratio of *Trichoderma* and *Fusarium oxysporum*. It also provides a graphene oxide sol, prepared in a laboratory, meeting the requirements of a particle size ≤5μm and a specific surface area >500 m². 2 / g requirement. Take the mixed low-temperature bacterial strain, add water and mix, stir thoroughly to disperse and obtain a low-temperature bacterial agent aqueous dispersion for later use; take the graphene sol, add water and mix, stir thoroughly to disperse and obtain a graphene oxide aqueous dispersion for later use.

[0019] The specific implementation method was selected from a maize-growing area located in Beicun Village, Datong City, Shanxi Province, at an altitude of 1000 m, with an average annual temperature of 6.7℃, a frost-free period of 128 days, and an average annual rainfall of 380 mm. The experiment included eight treatments arranged sequentially, with each plot covering an area of ​​36 m². 2 Each treatment was repeated three times.

[0020] Example 1 Using harvested corn stalks as the research object, the harvested corn stalk samples were crushed into small pieces less than 5 cm and spread on the ground. First, according to the graphene oxide dosage of 6.18 × 10⁻⁶... -7 Spray with a concentration of 10 kg / mu of graphene oxide aqueous dispersion, followed by a mixture of 10 kg / mu of low-temperature bacterial culture. 15 Spray a low-temperature bacterial agent aqueous dispersion at a dosage of CFU / acre. Use a rotary tiller to plow and cover the soil to a depth of 30cm and then cover with soil. Measure the total potassium content of the soil after 8 months, during which the temperature range is between -15 and 25℃.

[0021] Example 2 Using harvested corn stalks as the research object, the harvested corn stalk samples were crushed into small pieces less than 5 cm in size and spread on the ground. First, graphene oxide was applied at a dosage of 1.54 × 10⁻⁶. -5 Spray with a concentration of 10 kg / mu of graphene oxide aqueous dispersion, followed by a mixture of 10 kg / mu of low-temperature bacterial culture. 15 Spray a low-temperature bacterial agent aqueous dispersion at a dosage of CFU / acre. Use a rotary tiller to turn the soil to a depth of 20cm and cover it with soil. Measure the total potassium content of the soil after 8 months. During this period, the temperature range for mulching and heat preservation is between -15 and 25℃.

[0022] Example 3 Using harvested corn stalks as the research object, the harvested corn stalk samples were crushed into small pieces less than 5 cm and spread on the ground. First, according to the graphene oxide dosage of 6.18 × 10⁻⁶...-5 Spray with a concentration of 10 kg / mu of graphene oxide aqueous dispersion, followed by a mixture of 10 kg / mu of low-temperature bacterial culture. 15 Spray a low-temperature bacterial agent aqueous dispersion at a dosage of CFU / acre. Use a rotary tiller to plow and cover the soil to a depth of 40cm and then cover with soil. Measure the total potassium content of the soil after 8 months, during which the temperature range is between -15 and 25℃.

[0023] Comparative Example 1 Repeat Example 1, except that the application of the graphene oxide aqueous dispersion and the low-temperature bacterial agent aqueous dispersion is omitted, and the rest remains unchanged.

[0024] Comparative Example 2 Repeat Example 1, but omit the application of the low-temperature bacterial agent aqueous dispersion, and apply 6.18 × 10⁻⁶ graphene oxide aqueous dispersion. -7 kg / mu, with the rest remaining unchanged.

[0025] Comparative Example 3 Repeat Example 1, but omit the application of the low-temperature bacterial agent aqueous dispersion, and apply 1.54 × 10⁻⁶ graphene oxide aqueous dispersion. -5 kg / mu, with the rest remaining unchanged.

[0026] Comparative Example 4 Repeat Example 1, but omit the application of the low-temperature bacterial agent aqueous dispersion, and apply 6.18 × 10⁻⁶ graphene oxide aqueous dispersion. -5 kg / mu, with the rest remaining unchanged.

[0027] Comparative Example 5 Repeat Example 1, except that the application of the graphene oxide aqueous dispersion is omitted, and everything else remains the same.

[0028] The total potassium content in the soil after 8 months of in-situ corn straw return to the field in the examples and comparative cases was characterized. The results are shown in the appendix. Figure 1 As shown. Compared with Comparative Example 1, the total potassium content of Comparative Examples 2, 3, 4, 5 and Examples 1, 2, 3 increased significantly, with Example 2 showing the highest total potassium content. These results indicate that the addition of 1.54 × 10⁻⁶ potassium from an exogenous source is sufficient to significantly increase the total potassium content. -5 Spray graphene oxide aqueous dispersion at a rate of kg / mu, 10 15 The soil total potassium content was highest with a low-temperature bacterial agent aqueous dispersion of CFU / mu, reaching 3.47%.

Claims

1. A method for degrading straw using a graphene-enhanced low-temperature microbial agent, characterized in that... Includes the following steps: (1) Use a straw crusher to crush the straw on-site; (2) Spray the aqueous dispersion of graphene oxide using a sprayer; (3) Spray the aqueous dispersion of the low-temperature bacterial agent using a sprayer; (4) Use a rotary tiller to turn over and cover with soil to a depth of 20-40cm.

2. The method for degrading straw with graphene-enhanced low-temperature microbial agent as described in claim 1, characterized in that... Step (1) Crush the straw to a length of 1-5 cm.

3. The method for degrading straw with graphene-enhanced low-temperature microbial agents as described in claim 1, characterized in that... The graphene oxide in step (2) has a particle size ≤ 5 μm and a specific surface area > 500 m². 2 / g.

4. The method for degrading straw with graphene-enhanced low-temperature microbial agent as described in claim 1, characterized in that... The concentration of the aqueous dispersion of graphene oxide in step (2) is 5-50 mg / L.

5. The method for degrading straw with graphene-enhanced low-temperature microbial agent as described in claim 1, characterized in that... The amount of the aqueous dispersion of graphene oxide used in step (2) is 6.18 × 10⁻⁶. -7 kg / mu - 6.18×10 -5 kg / mu.

6. The method for degrading straw with graphene-enhanced low-temperature microbial agent as described in claim 1, characterized in that... The low-temperature fungal agent mentioned in step (3) is a fungal agent composed of Trichoderma and Fusarium oxysporum.

7. The method for degrading straw with graphene-enhanced low-temperature microbial agent as described in claim 1, characterized in that... The Trichoderma and Fusarium oxysporum were mixed in a 1:1 ratio.

8. The method for degrading straw with graphene-enhanced low-temperature microbial agent as described in claim 1, characterized in that... The dosage of the low-temperature microbial agent sprayed in step (3) is 10. 15 cfu / acre.

9. The method for degrading straw with graphene-enhanced low-temperature microbial agent as described in claim 1, characterized in that... Step (4) also includes covering the ground with plastic film for insulation when extreme low temperatures below -30°C occur.

10. The method for degrading straw with graphene-enhanced low-temperature microbial agent as described in claim 1, characterized in that... The optimized degradation temperature in step (4) is 10℃~25℃.

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