Preparation of straw organic copper pesticide degradation material and application method thereof

Abstract

The application belongs to the technical field of environmental remediation, and discloses a preparation of a straw organic copper pesticide degradation material and an application method thereof. The adsorption capacity of the straw is improved through oxidation treatment of the straw, and based on a one-step hydrothermal synthesis method, the straw organic copper composite material is prepared, the application conditions of the composite material are optimized, and the composite material is applied to reduction of pesticide residues in farmland soil, so that efficient degradation and removal of pesticides in farmland runoff water and soil are realized, which has certain application potential for prevention and treatment of farmland soil organic pollution. The straw organic copper pesticide degradation material prepared by the application has the characteristics of environmental friendliness and low preparation cost, and can be used as a reserve resource for prevention and control technology of farmland pesticide pollution.

Description

Technical Field

[0001] This invention belongs to the field of environmental remediation technology, specifically relating to the preparation and application method of a straw organic copper pesticide degradation material. Background Technology

[0002] Pesticides are a double-edged sword. To ensure grain yields and mitigate the impact of pests and weeds on crop health, my country consumes approximately 1.5 million tons of pesticides annually. With the continuous application of pesticides, the problem of pesticide residue pollution in the soil has become increasingly prominent, disrupting the normal ecosystem and stability of farmland soils. Residual pesticides in the soil are absorbed by crops and enter the human body through the food chain, thus harming human health. Furthermore, pesticide residues in the soil can enter nearby water bodies through rainwater leaching and runoff, causing pollution of rivers and groundwater. To reduce pesticide residue levels in the soil, various remediation technologies have been developed, including physical remediation, phytoremediation, and chemical remediation. However, these technologies are often costly or time-consuming. To achieve efficient degradation of organic pollutants and reduce the cost of technology application, it is necessary to develop targeted in-situ remediation technologies that combine production and remediation. This would allow for the in-situ removal of pollutants without affecting normal crop growth, contributing to the healthy and sustainable development of farmland soils, ensuring food production security, and achieving the goal of remediation during production.

[0003] Persulfate, as a mild oxidant, is often used for the remediation of organic soil pollution. Its effectiveness in degrading pollutants is influenced by soil physicochemical properties, such as soil pH, dissolved organic matter content, and ionic strength. To improve the chemical activity of the oxidant, persulfate often needs to be activated to enhance its efficiency and selectivity, thereby achieving efficient removal of organic pollutants. Chinese invention patent (CN201711327201.2) discloses a persulfate activator, its preparation method, and its application. The persulfate activator, Ni-xFe-(3-)-xO-4, is prepared by high-temperature calcination and activated to degrade antibiotics in wastewater. Chinese invention patent (CN202010492665.4) discloses a method for removing ibuprofen using persulfate activation. Ferric chloride, sodium sulfate, and disodium hydrogen phosphate are simultaneously placed in a hydrothermal reactor to prepare the nanomaterial α-Fe₂O₃. This nanomaterial is then thoroughly ground and mixed with sodium hypophosphite and calcined to obtain ferric phosphide (Fe₂P@FeP), thus preparing an active material capable of activating persulfate to degrade ibuprofen. Therefore, using metal ions to activate persulfate can efficiently degrade organic pollutants. However, the preparation process of these materials is complex, requires energy, and has high application costs, making them unsuitable for large-scale application in farmland soils.

[0004] This invention improves the adsorption capacity of straw materials through simple pretreatment, and then prepares straw-organic copper composite materials based on hydrothermal synthesis. A three-dimensional rotary granulation method is then used to obtain a straw-organic copper and persulfate compound material, which is applied to reduce pesticide residues in farmland soil, achieving efficient removal of pesticide residues from farmland runoff and soil. The preparation process of this straw-organic copper composite material is simple and low-cost, making it suitable for application and promotion in reducing organic pollution residues such as pesticides in farmland soil. Summary of the Invention

[0005] This invention provides a method for preparing and applying a straw-based organic copper pesticide degradation material. By oxidizing straw to enhance its adsorption capacity, a straw-based organic copper composite material is prepared using a one-step hydrothermal synthesis method. Simultaneously, the application conditions of the composite material are screened and optimized, and it is applied to reduce pesticide residues in farmland soil, achieving efficient degradation and removal of pesticides from farmland runoff and soil. This has certain application potential for the prevention and control of organic pollution in farmland soil.

[0006] The technical solution of this invention:

[0007] A method for preparing a straw-based organic copper pesticide degradation material includes the following steps:

[0008] (1) Oxidation treatment of straw: Add 5-20% hydrogen peroxide solution and 10-20 times the amount of pure water by weight of straw to straw powder with a particle size range of 0.1mm-5mm. Adjust the pH of the reaction solution to 10-12, stir evenly, and then add 0.5-2% urea by weight of straw. Stir rapidly, control the temperature at 40-60℃, and sonicate for 2-5 hours. After filtration, wash with pure water 2-3 times, and dry thoroughly at 60-70℃ to obtain oxidized straw powder. The concentration of hydrogen peroxide solution is 30-40 wt.%.

[0009] (2) Preparation of straw-organic copper composite material: Add 2-5 times the weight of straw in aqueous N,N-dimethylformamide solution and 2-5 times the weight of straw in anhydrous ethanol to the straw powder oxidized in step (1). The volume ratio of the two liquids is controlled at 1:1. Stir thoroughly and sonicate at room temperature for 5-10 min. Add 10-20% of straw weight of 1,3,5-benzenetricarboxylic acid and 0.1-0.5% of straw weight of acetic anhydride. Stir evenly and sonicate at 30-40℃ for 20-60 min. Add 15-30% of straw weight of copper nitrate trihydrate solid and 0.1-2% of straw weight of dimethylformamide. After thorough stirring, the silica solid was ultrasonicated at room temperature for 10-15 minutes, then sealed and placed in a forced-air drying oven at 50-80% airflow for 5-20 hours at 80-150℃. After cooling to room temperature, it was washed 3-5 times sequentially with an aqueous N,N-dimethylformamide solution and pure water. The synthesized material was then placed in a vacuum drying oven and dried thoroughly at 60-80℃ for 15-24 hours to obtain a solid powder of straw organic copper pesticide degradation material. This powder was then packaged in a sealed bag and stored at room temperature for later use. The concentration of the aqueous N,N-dimethylformamide solution was 40-80 wt.%.

[0010] The application of a straw-based organic copper pesticide degradation material involves the following steps:

[0011] Straw-based organic copper pesticide degradation material and persulfate are mixed at a mass ratio of (10-50):1 using a three-dimensional mixer. During the mixing process, 5%-20% of the straw mass as a vegetable oil binder is added. The mixing time is set to 10-30 minutes to obtain composite material and persulfate compound granules. The composite material and persulfate compound granules are applied to the periphery of farmland using strip or hole application methods. The trenches are 20-40 cm deep and 10-20 cm wide, and the surface is filled with soil to prevent the loss and spread of pesticide residues in the soil.

[0012] The straw includes the straw of crops such as corn, wheat, rice, and cotton; the pesticides include herbicides such as atrazine and acetochlor, insecticides such as imidacloprid and acetamiprid, and fungicides such as thiamethoxam and chlorothalonil.

[0013] The persulfates include sodium persulfate, potassium persulfate, ammonium persulfate, etc.

[0014] The vegetable oils include oils derived from soybeans, corn, peanuts, etc.

[0015] The dosage of the prepared mixed agent is 2-5 kg ​​per meter of length, applied in strip or hole application.

[0016] The beneficial effects of this invention are as follows: This invention prepares straw-organic copper composite material, screens and optimizes the application conditions of the composite material, and applies it to the reduction of pesticide residues in farmland soil, achieving simultaneous and efficient removal of pesticides from farmland runoff and soil. This composite material is environmentally friendly and has low preparation cost, and can be used as a reserve resource for farmland pesticide pollution control technology. Attached Figure Description

[0017] Figure 1 This is a microscopic morphology diagram of straw-organic copper composite material.

[0018] Figure 2 It refers to the surface copper content of straw-organic copper composite materials.

[0019] Figure 3 The effect of straw composite materials prepared under different conditions on the removal of atrazine.

[0020] Figure 4 It is the effect of straw-organic copper composite material in removing atrazine from the soil. Detailed Implementation

[0021] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0022] Example 1: Preparation of straw-based organic copper materials

[0023] Take 20g of dried and crushed straw powder, add it to a glass beaker, then add 2mL of 30% hydrogen peroxide solution, pour in 200mL of water, adjust the pH of the solution to 11, add 0.2g of urea, stir quickly, control the temperature at 50℃, sonicate for 2h, filter, wash twice with pure water, and then dry thoroughly in a 60℃ forced-air drying oven. Oxidized straw powder was added to a polytetrafluoroethylene hydrothermal reactor, followed by 40 mL of 50 wt% aqueous N,N-dimethylformamide solution and 40 mL of anhydrous ethanol. The mixture was stirred thoroughly and sonicated at room temperature for 5 min. Then, 2.8 g of 1,3,5-benzenetricarboxylic acid and 0.03 g of acetic anhydride were added, and the mixture was stirred until homogeneous and sonicated at 30℃ for 25 min. Finally, 6.0 g of copper nitrate trihydrate solid and 0.02 g of silica solid were added, and the mixture was stirred thoroughly and sonicated at room temperature for 10 min. The reactor was then sealed and placed in a forced-air drying oven at 80℃ for 15 h. After cooling to room temperature, the mixture was washed three times with N,N-dimethylformamide and pure water. The synthesized material was then placed in a vacuum drying oven and dried thoroughly at 65℃ for 18 h. The resulting solid powder was stored in a sealed bag at room temperature for later use. Scanning electron microscopy revealed that the surface of the straw-organic copper composite material exhibited uneven protrusions. Figure 1This is due to the hydrogen bonding between organic copper and cellulose in the crystalline regions inside the straw, while the surface of the straw composite material contains 1.1% copper. Figure 2 These copper elements are evenly distributed on the surface of the composite material.

[0024] Example 2: Screening of straw-organic copper composite materials

[0025] Following the preparation steps of the straw-organic copper composite material in Example 1, the temperature of the hydrothermal reaction of the straw-organic copper composite material was changed. The reaction temperature was set to 80℃, 100℃, 120℃, 150℃, and 180℃, and the reaction time was 15h for each temperature, while other conditions remained unchanged. Simultaneously, control experiments were conducted by adding 2.8g of 1,3,5-benzenetricarboxylic acid, 0.03g of acetic anhydride, 6.0g of copper nitrate trihydrate solid, and 0.02g of silica solid at a reaction temperature of 80℃. Other reaction conditions and preparation processes were carried out according to Example 1, resulting in straw composite materials prepared under different reaction temperatures and with the addition of a single reactive component. 0.05 g of straw composite materials prepared under different reaction temperatures and with the addition of a single reactive component were successively added to a reaction flask. 50 mL of a 10 mg / L atrazine solution was poured in, followed by 40 μL of a 100 g / L sodium persulfate solution. The reaction was carried out at 25 °C. After 24 h, samples were taken to test the concentration of atrazine in the reaction solution and analyze the atrazine removal rate. Figure 3 It was found that after 24 hours of reaction, among the straw composite materials prepared with the addition of a single reactive component, the straw composite material prepared with the addition of 6.0 g of copper nitrate trihydrate solid showed the highest removal rate of atrazine (18%), while the straw composite materials prepared with the addition of other single reactive components showed relatively low removal rates, ranging from 3.6% to 8.7%. Conversely, the straw-organic copper composite materials prepared under different reaction temperatures could effectively remove atrazine from the solution, with removal rates ranging from 76% to 93%. Among them, the straw-organic copper composite material prepared at 150℃ showed the best removal effect of atrazine (93%). Overall, the straw-organic copper composite material prepared at 80℃ showed a 3.2-20.1 times higher removal rate of atrazine compared to the straw composite materials prepared with the addition of a single reactive component.

[0026] Example 3: Application of straw-organic copper composite material in the control of herbicide pollution in farmland

[0027] 10 kg of the straw-organic copper composite material prepared at 150℃ as selected in Example 2, and 0.5 kg of sodium persulfate were mixed in a three-dimensional mixer to prepare compound granules. 0.5 kg of soybean vegetable oil was added during the preparation process, and the mixing reaction time was set to 20 min. Around atrazine-contaminated farmland, trenches 5 m long, 40 cm deep, and 10 cm wide were dug. The mixed herbicide was evenly applied into the trenches, and the surface was filled with soil. Simultaneously, control groups consisting of pure straw-organic copper composite material and sodium persulfate alone were set up. Soil samples were collected from the trench surface after 5 days to determine the concentration of the herbicide in the soil and calculate the atrazine removal rate (%). Figure 4 It can be seen that the compound granules can achieve a removal rate of 82.7% for atrazine, which is higher than the removal rates of the two control groups: sodium persulfate alone (23.3%) and straw-based organic copper composite material alone (5.9%). Therefore, the compound granules can effectively remove the herbicide atrazine from contaminated soil.

Claims

1. A method for preparing a straw-based organic copper pesticide degradation material, characterized in that, The steps are as follows: (1) Oxidation treatment of straw: Add 5-20% hydrogen peroxide solution and 10-20 times the weight of pure water to straw powder with a particle size range of 0.1 mm-5 mm. Adjust the pH of the reaction solution to 10-12, stir evenly, then add 0.5-2% urea solution by weight of straw, stir rapidly, control the temperature at 40-60℃, and sonicate for 2-5 hours. After filtration, wash with pure water 2-3 times, and dry thoroughly at 60-70℃ to obtain oxidized straw powder; wherein the concentration of hydrogen peroxide solution is 30-40 wt.%. (2) Preparation of straw-organic copper composite material: Add 2-5 times the weight of straw in aqueous N,N-dimethylformamide solution and 2-5 times the weight of straw in anhydrous ethanol to the straw powder oxidized in step (1). The volume ratio of the two liquids is controlled at 1:

1. Stir thoroughly and sonicate at room temperature for 5-10 min. Add 10-20% of straw weight of 1,3,5-benzenetricarboxylic acid and 0.1-0.5% of straw weight of acetic anhydride. Stir evenly and sonicate at 30-40℃ for 20-60 min. Add 15-30% of straw weight of copper nitrate trihydrate solid and 0.1-2% of straw weight of silica solid. Stir thoroughly and sonicate at room temperature for 10-15 min. Then seal and place in a forced-air drying oven with a wind speed of 50-80% and react at 80-150℃ for 5-20 minutes. After cooling to room temperature, the material is washed 3-5 times with an aqueous N,N-dimethylformamide solution and pure water. The synthesized material is then placed in a vacuum drying oven and dried thoroughly at 60-80℃ for 15-24 hours to obtain a solid powder of straw organic copper pesticide degradation material. This powder is then placed in a sealed bag and stored at room temperature for later use. The concentration of the aqueous N,N-dimethylformamide solution is 40-80 wt.%.

2. The preparation method according to claim 1, characterized in that, The straw includes the straw of corn, wheat, rice, and cotton.

3. The preparation method according to claim 1, characterized in that, The pesticides include herbicides atrazine and acetochlor, insecticides imidacloprid and acetamiprid, and fungicides thiabendazole and chlorothalonil.

4. The application of a straw-based organic copper pesticide degradable material prepared by the preparation method according to any one of claims 1-3, characterized in that, The steps are as follows: The straw-based organic copper pesticide degradation material is mixed with persulfate at a mass ratio of (10-50):1 using a three-dimensional mixer. During the mixing process, 5%-20% of the straw mass is added as a vegetable oil binder. The mixing time is set to 10-30 minutes to obtain composite material and persulfate compound granules. The composite material and persulfate compound granules are applied to the outer perimeter of farmland using strip or hole application methods. The trenches are 20-40 cm deep and 10-20 cm wide, and the surface is filled with soil to prevent the loss and spread of pesticide residues in the soil.

5. The application according to claim 4, characterized in that, The vegetable oils include oils derived from soybeans, corn, and peanuts.

6. The application according to claim 4, characterized in that, The dosage of the straw organic copper pesticide degradation material is 2-5 kg ​​per meter of length, applied in strip or hole application.

7. The application according to claim 4, characterized in that, The persulfates include sodium persulfate, potassium persulfate, and ammonium persulfate.

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