Emamectin benzoate-LDHs (layered double hydroxides) composite nano pesticide as well as preparation method and application thereof
By preparing abamectin-LDHs composite nanopesticides and using Mg-Al type SDS-modified LDHs nanomaterials as carriers, the problems of single function and poor environmental adaptability of abamectin slow-release formulations have been solved. This achieves the dual functions of slow release and plant growth promotion, and has the advantages of high efficiency, environmental protection and economy.
Patent Information
- Application Number
- CN202510785144.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-12
- Publication Date
- 2025-10-31
AI Technical Summary
Existing abamectin sustained-release formulations have limited functions, poor environmental adaptability, and high ecological risks. Furthermore, there is limited research on existing nanomaterials for promoting plant growth.
Using Mg-Al type SDS-modified LDH nanomaterials as a carrier, abamectin-LDH composite nanopesticides were prepared. The abamectin and LDHs were combined by freeze-drying to form a nanoscale layered structure, thereby achieving slow release and plant growth promotion functions.
It achieves good slow-release effect, excellent resistance to photodegradation, and high stability of abamectin, while also having plant growth-promoting function. It has both environmental and economic advantages and is suitable for large-scale production.
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Figure CN120859007A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of pesticide formulation technology, specifically relating to an abamectin-LDHs composite nanopesticide, its preparation method, and its application. Background Technology
[0002] Abamectin is a macrolide antibiotic pesticide isolated from the fermentation product of Streptomyces avermitilis. It works by interfering with glutamate-gated chloride channels in the nervous system of pests through stomach poisoning and contact action, leading to paralysis, cessation of feeding, and death. It exhibits good insecticidal and acaricidal effects, but suffers from drawbacks such as photodegradation and poor stability. Formulating abamectin into nano-scale sustained-release formulations can not only extend its effective period, improve efficacy and utilization, but also reduce environmental pollution and the number of applications, representing an important direction for the development of modern green pesticides.
[0003] Nano-release formulations of abamectin mainly achieve sustained release or anti-photodegradation functions through different carrier materials (such as zein, lignin sulfonate, sodium alginate, and metal-organic frameworks). Among these, zein, using abamectin as a carrier material, releases abamectin through pH or enzyme response, exhibiting small particle size and good dispersibility, but its function is relatively limited. Using lignin sulfonate-based nanoparticles as a carrier material (utilizing lignin sulfonate as a granulating agent, combined with surfactants and thickeners), the resulting abamectin sustained-release pesticide exhibits excellent anti-photodegradation performance (decomposition rate approximately 3% after 75 hours of sunlight exposure). However, lignin molecules have irregular structures, high branching, and limited affinity for emamectin benzoate, resulting in low drug loading and poor stability. Sodium alginate composite systems can be used as carrier materials to form nanoparticles through electrostatic self-assembly, exhibiting resistance to photolysis, sustained release, and systemic conductivity. However, the preparation process requires the use of organic solvents, limiting its environmental friendliness. Metal-organic framework (MOF) controlled-release systems, such as EB@PCN-222@HA, can utilize alkaline environments to release emamectin benzoate with strong targeting. However, the safety of non-targeted drugs still needs to be verified, and the preparation process is complex and costly.
[0004] On the other hand, current plant growth regulators mainly rely on chemical hormones, such as gibberellins and auxins. These chemical hormones promote growth by directly intervening in plant physiological processes. The current application of nanomaterials in agriculture is mostly focused on slow-release carriers of pesticides or fertilizers (such as silica nanoparticles), while research on nanomaterials that also promote plant growth is relatively limited, especially materials that are both environmentally friendly and multifunctional.
[0005] Layered bimetallic hydroxides (LDHs) are a class of anionic layered materials that are biodegradable, leave no chemical residues, are environmentally friendly, and possess characteristics such as large specific surface area, excellent ion exchange capacity, and good slow-release performance. The inventors have also discovered that LDHs can promote plant growth. Based on this, this invention proposes to use LDHs as a carrier material to prepare abamectin-LDHs composite nanopesticides, a process not yet reported in existing technologies. Summary of the Invention
[0006] The purpose of this invention is to solve the problems of single function, poor environmental adaptability and high ecological risk of existing abamectin slow-release formulations. It provides an abamectin-LDHs composite nanopesticide and its preparation method. The abamectin-LDHs composite nanopesticide has good slow-release effect of abamectin, excellent resistance to photodegradation, good stability, and also has plant growth-promoting function, and has the advantages of high efficiency, environmental protection and economy.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A method for preparing an abamectin-LDHs composite nanopesticide: Mg-Al type SDS modified LDHs nanomaterials and abamectin are added to anhydrous ethanol, stirred evenly, and then the anhydrous ethanol is removed and freeze-dried to obtain the abamectin-LDHs composite nanopesticide.
[0009] The preparation method of the Mg-Al type SDS modified LDHs nanomaterial includes the following steps:
[0010] (1) Add MgCl2·6H2O and AlCl3·6H2O to deionized water, stir to dissolve, and obtain a mixed salt solution;
[0011] (2) Add ammonia solution and sodium hydroxide solution to the mixed salt solution until the pH value reaches 10±0.2. After standing, centrifuge to obtain the precipitate.
[0012] (3) After washing the precipitate with deionized water, seal it in a glass container and dry it in an oven to obtain Mg / Al-LDH sol;
[0013] (4) The Mg / Al-LDH sol was dispersed in the SDS solution, the pH was adjusted to 10±0.2 with sodium hydroxide solution, stirred at room temperature for 40-50 h, filtered and washed with deionized water, and the precipitate obtained was Mg-Al type SDS modified LDH nanomaterial.
[0014] Furthermore, the mass ratio of the Mg-Al type SDS-modified LDH nanomaterial to abamectin is 1:(1.2~2.5).
[0015] Furthermore, the freeze-drying temperature is -40℃ to -20℃, and the time is 10 to 20 hours.
[0016] Furthermore, in step (1), the molar ratio of MgCl2·6H2O and AlCl3·6H2O is 2:1.
[0017] Furthermore, in step (2), the centrifugation speed is 3000-5000 rpm and the time is 5-10 min.
[0018] Furthermore, in step (3), the drying temperature is 80°C and the time is 20-30 hours.
[0019] Furthermore, in step (4), the amount of Mg / Al-LDH sol and SDS is calculated according to the molar ratio of Mg, Al and SDS, and the molar ratio of Mg:Al:SDS is 4:2:1.
[0020] The abamectin-LDHs composite nanopesticide was prepared using the above method.
[0021] The application of the abamectin-LDHs composite nanopesticide prepared by the above method in promoting plant growth.
[0022] Compared with the prior art, the present invention has the following advantages:
[0023] 1) This invention uses Mg-Al type SDS-modified LDH nanomaterials as a carrier for abamectin. LDH nanomaterials are biodegradable, leave no chemical residues, are environmentally friendly, and avoid the pollution problems of traditional chemical hormones. Furthermore, their raw materials are readily available, the preparation process is simple, suitable for large-scale production, reducing fertilization frequency and lowering agricultural production costs. These LDH nanomaterials not only promote plant growth but can also load other nutrients or pesticides, achieving multiple uses and applicability to various crops, showing broad application prospects. Moreover, the SDS modification enhances the hydrophobicity of LDHs, improving their stability in soil.
[0024] 2) The abamectin-LDHs composite nanopesticide prepared in this invention can effectively delay the degradation of abamectin in the soil through the interlayer confinement effect of LDHs, reducing the application frequency. LDHs directly promote plant growth, achieving an integrated "pesticide-fertilizer" function. The composition of LDHs (e.g., Mg-Al-LDHs, Zn-Al-LDHs) can be optimized for different soil types (e.g., acidic red soil, neutral brown soil) to improve the universality of degradation regulation. The preparation process of this invention uses anhydrous ethanol as a solvent, which meets the requirements of green chemistry.
[0025] 3) This invention achieves the dual functions of slow release of abamectin and plant growth promotion through LDHs carriers, which has the advantages of high efficiency, environmental protection and economy, and solves the problems of single function, poor environmental adaptability and high ecological risk in the existing technology. Attached Figure Description
[0026] Figure 1 TEM and SEM images of the abamectin-LDHs composite nanopesticide prepared in Example 1;
[0027] Figure 2 Photographs of soybean seedlings obtained under different LDH treatment concentrations;
[0028] Figure 3 The results of tests on root length, plant height, number of roots, total weight, leaf width, and number of leaves of soybean seedlings obtained under different LDH treatment concentrations;
[0029] Figure 4 This is the standard curve for emamectin benzoate;
[0030] Figure 5 The degradation curves of the abamectin-LDHs composite nanopesticide and abamectin technical prepared in Example 1 in loess are shown.
[0031] Figure 6 The degradation curves of the abamectin-LDHs composite nanopesticide and abamectin technical prepared in Example 1 in laterite soil are shown.
[0032] Figure 7 The degradation curves of the abamectin-LDHs composite nanopesticide and abamectin technical prepared in Example 1 in black soil are shown. Detailed Implementation
[0033] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the scope of protection of the present invention is not limited to the specific implementation.
[0034] Example 1
[0035] Preparation of Mg-Al type SDS-modified LDH nanomaterials:
[0036] (1) Add 4.04g MgCl2·6H2O and 2.4g AlCl3·6H2O to 50mL of deionized water, stir to dissolve, and obtain a mixed salt solution;
[0037] (2) Add 6 mL of ammonia water to 94 mL of deionized water to obtain an ammonia solution with a concentration of 6%. Slowly add the ammonia solution to the mixed salt solution obtained in step (1) and add a sodium hydroxide solution with a mass concentration of 10% while stirring until the pH value reaches 10±0.2. After standing for 45 min, centrifuge at 4000 rpm for 5 min to obtain the precipitate.
[0038] (3) After washing the precipitate with deionized water, seal it in a glass container and dry it in an oven at 80°C for 24 hours to obtain Mg / Al-LDH sol.
[0039] (4) The Mg / Al-LDH sol was dispersed in a 0.1 mol / L SDS solution. The amount of Mg / Al-LDH sol and SDS was calculated according to the molar ratio of Mg, Al and SDS, Mg:Al:SDS = 4:2:1. The pH value was adjusted to 10±0.2 using a 10% sodium hydroxide solution. The mixture was stirred at room temperature for 48 h, filtered and washed with deionized water. The precipitate obtained was Mg-Al type SDS modified LDH nanomaterial.
[0040] Abamectin-LDHs composite nanopesticide was prepared using the Mg-Al type SDS modified LDHs nanomaterials described above: 1.5 g of Mg-Al type SDS modified LDHs nanomaterials and 3.21 g of abamectin (70% purity) were added to 120 mL of anhydrous ethanol, stirred evenly, and the anhydrous ethanol was evaporated. The mixture was then freeze-dried at -40℃ to -20℃ under vacuum for 12 h to obtain the abamectin-LDHs composite nanopesticide.
[0041] Figure 1 TEM and SEM images of the abamectin-LDHs composite nanopesticide prepared in Example 1 are shown. Figure 1 a is the TEM image. Figure 1 b is the SEM image, such as Figure 1 As shown in Figure a, the TEM image of the abamectin-LDHs composite nanopesticide exhibits a layered and sheet-like structure with a size between 64.7 nm and 96.8 nm, belonging to the nanoscale. Meanwhile, according to... Figure 1 The scanning electron microscope (SEM) image (b) clearly shows that the abamectin-LDHs composite nanopesticide has a hexagonal and hexagonal plate-like morphology. Furthermore, the morphological field of view of the abamectin-LDHs composite nanopesticide does not show the blocky structure of the abamectin technical material. Simultaneously, the hybrid nanopesticide conforms to the structural morphology characteristics of LDHs nanocarriers and its size is within the nanoscale range, indicating that the abamectin-LDHs composite nanopesticide was successfully prepared.
[0042] 1. Testing of soybean growth performance
[0043] (1) Experimental materials and grouping:
[0044] Plant material: soybean seeds, variety Zhonghuang 13.
[0045] LDHs treatment solution: 200 mg of Mg-Al type SDS modified LDHs nanomaterials were dispersed in 200 mL of deionized water and ultrasonically treated for 30 min to obtain LDHs treatment solution.
[0046] Experimental groups: The experiment was divided into three treatment groups: 0 ppm, 10 ppm, and 100 ppm, with three replicates for each group.
[0047] (2) Specific experimental steps:
[0048] Step 1: Seed germination. Disinfect soybean seeds with 1% NaClO for 10 minutes, then rinse them 7 times with sterile deionized water, and then germinate them in the dark at 28°C for 48 hours on moist sterile filter paper.
[0049] Step 2: Soil addition. For the 0ppm group, add 200g of soil per pot without any treatment; for the 10ppm group, add 200g of soil per pot and mix well with 2mL of LDHs treatment solution; for the 100ppm group, add 200g of soil per pot and mix well with 20mL of LDHs treatment solution.
[0050] Step 3: Soybean planting. Plant soybeans 2 mL away from the soil surface, press down the surface soil, and then water to moisten the soil.
[0051] Step 4: Water regularly, cultivate for 28 days, and measure the biomass of the three groups of soybeans, including plant height, root length, number of leaves, number of roots, and leaf width.
[0052] (3) Experimental results:
[0053] Figure 2 The images show soybean seedlings obtained under different LDH concentrations. As shown in the figure, soybeans were cultured for 28 days at LDH concentrations of 0 ppm, 10 ppm, and 100 ppm. The higher the concentration, the better the growth, indicating that LDHs have a promoting effect on soybean growth.
[0054] Figure 3 The results show the root length, plant height, root number, total weight, leaf width, and leaf number of soybean seedlings obtained under different LDH treatment concentrations. Figure 3 A represents the root length test results of soybean seedlings. Figure 3 B represents the plant height test results for soybean seedlings. Figure 3 C represents the root count test result of soybean seedlings. Figure 3 D represents the total weight test result of the soybean seedlings. Figure 3 E represents the leaf width test result of soybean seedlings. Figure 3F represents the results of the soybean seedling leaf number test. It can be seen that compared with the 0 ppm LDHs treatment group (control group), the 10 ppm and 100 ppm LDHs treatment groups showed significantly increased biomass indicators for soybeans. Among them, the 100 ppm LDHs treatment group showed the best effect, with increases in plant height, root length, root number, leaf width, leaf number, and total weight of 61.1%, 151.6%, 133.3%, 37.4%, 94.1%, and 101.8%, respectively. Within the range of 100 ppm, LDHs nanomaterials exhibited a dose-dependent effect; the higher the concentration, the more significant the promoting effect.
[0055] 2. Drug loading test
[0056] First, prepare a 1000 mg / kg emamectin benzoate stock solution for later use. Then, dilute the 1000 mg / kg emamectin benzoate stock solution to prepare standards with concentration gradients of 0.1 mg / kg, 0.2 mg / kg, 0.5 mg / kg, 1 mg / kg, 2 mg / kg, 4 mg / kg, and 5 mg / kg, respectively. The emamectin benzoate standard curve was obtained as y = 92499x - 314.6, with a correlation coefficient R0. 2 =0.99 (e.g.) Figure 4 0.02 g of the abamectin-LDHs composite nanopesticide prepared in Example 1 was dissolved in methanol and sonicated for 5 minutes to completely release the abamectin. Then, 1 mL of the solution was diluted with methanol and filtered through a 0.22 μm filter membrane to prepare the sample to be tested. The loading of the abamectin-LDHs composite nanopesticide was calculated according to the formula for calculating the loading capacity.
[0057]
[0058] The test results showed that the loading capacity of the abamectin-LDHs composite nanopesticide prepared in Example 1 was 63%.
[0059] 3. Exposure experiments in soil
[0060] Experimental methods:
[0061] (1) Weigh 500g of each type of soil (as shown in Table 1) into a 1L brown wide-mouth bottle, and then add the abamectin-LDHs composite nano pesticide and abamectin technical prepared in Example 1 respectively. The concentration of the added pesticide is 1mg / kg. Then adjust the soil moisture content to 40%, and then place it in a constant temperature incubator at 25±1℃ in the dark. Weigh and add water every day to keep the moisture content constant. Take samples at 0, 1, 3, 7, 14, 21 and 28 days respectively, and take 3 parallel samples at each time point.
[0062] Table 1 Soil Properties
[0063]
[0064] (2) Accurately weigh 10g of soil sample into a 50mL centrifuge tube; add 10mL of acetonitrile (containing 1% acetic acid), vortex for 1min; extract by sonication for 15min (40kHz, 25℃); add 4g of anhydrous magnesium sulfate and 1g of NaCl, shake vigorously for 2min; centrifuge for 10min (4500rpm, 4℃); take the supernatant, add 150mg of PSA and 50mg of C18, vortex for 1min; centrifuge for 5min (4500rpm, 4℃); take the supernatant and blow it with nitrogen; add 1mL of methanol to make up to volume; filter through a 0.22μm organic phase membrane for UPLC-MS / MS analysis.
[0065] Table 2 Mobile phase gradients used in HPLC-MS / MS instrument analysis
[0066]
[0067] Based on the UPLC-MS / MS analysis results, the recovery rates of the abamectin-LDHs composite nanopesticide prepared in Example 1 were calculated in different soil types. The recovery rate was calculated as [(measured amount - original amount) / added amount] * 100%, and the results are shown in Table 3.
[0068] Table 3. Recovery rates of abamectin in different soils (n=5)
[0069]
[0070] As shown in Table 3, at addition concentrations of 0.01 mg / kg, 0.1 mg / kg, and 1 mg / kg, the recoveries of the abamectin-LDHs composite nanopesticide prepared in Example 1 in soil ranged from 93.15% to 109.47%, with relative deviations ranging from 1.49% to 6.3%. This indicates that the method is suitable for the extraction of abamectin-LDHs composite nanopesticides from soil, and the analytical method meets the pesticide residue standards.
[0071] The half-life of the abamectin-LDHs composite nanopesticide (denoted as LDHs-EB nanopesticide) and EB technical prepared in Example 1 in artificial soil was analyzed using the above-mentioned HPLC-MS / MS instrument detection method: the pesticide residue in the soil was measured at each sampling time, with time on the horizontal axis and concentration on the vertical axis. The degradation trend was represented by an exponential decrease curve, i.e., C t =G0·e -kt The degradation curves of LDHs-EB nanopesticides and EB technical were obtained in three types of soil, as shown in the figure. Figure 5-7 As shown, where, Figure 5 The degradation curves of the emamectin benzoate-LDHs composite nanopesticide (LDHs-EB nanopesticide) and emamectin benzoate technical (EB) prepared in Example 1 in loess are shown. Figure 6The degradation curves of the emamectin benzoate-LDHs composite nanopesticide (LDHs-EB nanopesticide) and emamectin benzoate technical (EB) prepared in Example 1 in laterite soil are shown. Figure 7 The degradation curves of the emamectin benzoate-LDHs composite nanopesticide (LDHs-EB nanopesticide) and emamectin benzoate technical (EB) prepared in Example 1 in black soil are shown. The half-life was calculated based on the degradation curves: t 1 / 2 =ln2 / k (time required for concentration to halve). It can be seen that in Hefei-Loess soil, the half-life of LDHs-EB nanopesticide is 19.8 days, while the half-life of the technical grade is 6.42 days; in Yunnan-Red soil, the half-life of LDHs-EB nanopesticide is 30.13 days, while the half-life of the technical grade is 15.07 days; and in Heilongjiang-Black soil, the half-life of LDHs-EB nanopesticide is 24.75 days, while the half-life of the technical grade is 15.75 days. The half-lives of the abamectin-LDHs composite nanopesticide prepared in Example 1 are all greater than those of the technical grade abamectin, indicating that the LDHs-EB nanopesticide has a slow-release effect in soil compared to the technical grade. Through a 28-day cultivation experiment, the degradation behavior of the abamectin-LDHs composite nanopesticide and the technical grade prepared in Example 1 in three soils was studied. The degradation data were fitted using a first-order kinetic equation, and the following kinetic parameters were obtained (Table 4):
[0072] Table 4 Degradation kinetic parameters of nano-pesticides and technical grade pesticides in three types of soil.
[0073]
[0074] The results showed that the degradation rates of the abamectin-LDHs composite nanopesticide prepared in Example 1 and the abamectin technical grade differed significantly in different soils (p<0.05). The fastest degradation was observed in loess (t<0.05). 1 / 2 =19.8d), which is related to its organic matter content. Organic matter, as an energy source for microorganisms, increases the activity of microorganisms in the soil, thereby promoting pesticide degradation. In contrast, degradation in red soil is the slowest (t). 1 / 2 =30.1d), which is mainly attributed to its lower pH and organic matter content. Under acidic conditions, pesticide molecules may undergo dissociation, and the degradation activity of microorganisms may be enhanced. The degradation behavior in black soil is intermediate between that in loess and red soil (t 1 / 2 =24.75d). The Freundlich adsorption model fitting results show that the black soil has the highest adsorption constant Kf (5.23), indicating that it has the strongest adsorption capacity for abamectin. This adsorption-desorption behavior directly affects the bioavailability and degradation rate of pesticides in the soil.
Claims
1. A method for preparing an abamectin-LDHs composite nanopesticide, characterized in that, Mg-Al type SDS modified LDHs nanomaterials and abamectin were added to anhydrous ethanol, stirred evenly, and then the anhydrous ethanol was removed. The mixture was then freeze-dried to obtain abamectin-LDHs composite nanopesticide. The preparation method of the Mg-Al type SDS modified LDHs nanomaterial includes the following steps: (1) Add MgCl2·6H2O and AlCl3·6H2O to deionized water, stir to dissolve, and obtain a mixed salt solution; (2) Add ammonia solution and sodium hydroxide solution to the mixed salt solution until the pH value reaches 10±0.
2. After standing, centrifuge to obtain the precipitate. (3) After washing the precipitate with deionized water, seal it in a glass container and dry it to obtain Mg / Al-LDH sol; (4) The Mg / Al-LDH sol was dispersed in the SDS solution, the pH was adjusted to 10±0.2 with sodium hydroxide solution, stirred at room temperature for 40-50 h, filtered and washed with deionized water, and the precipitate obtained was Mg-Al type SDS modified LDH nanomaterial. In step (1), the molar ratio of MgCl2·6H2O and AlCl3·6H2O is 2:
1.
2. The preparation method of the abamectin-LDHs composite nanopesticide as described in claim 1, characterized in that, The mass ratio of the Mg-Al type SDS-modified LDH nanomaterial to abamectin is 1:(1.2~2.5).
3. The preparation method of the abamectin-LDHs composite nanopesticide as described in claim 1, characterized in that, The freeze-drying temperature is -40℃ to -20℃, and the time is 10 to 20 hours.
4. The preparation method of the abamectin-LDHs composite nanopesticide as described in claim 1, characterized in that, In step (2), the centrifugation speed is 3000-5000 rpm and the time is 5-10 min.
5. The preparation method of the abamectin-LDHs composite nanopesticide as described in claim 1, characterized in that, In step (3), the drying temperature is 80°C and the time is 20-30 hours.
6. The preparation method of the abamectin-LDHs composite nanopesticide according to any one of claims 1 to 5, characterized in that, In step (4), the amount of Mg / Al-LDH sol and SDS is calculated according to the molar ratio of Mg, Al and SDS, and the molar ratio of Mg:Al:SDS is 4:2:
1.
7. The abamectin-LDHs composite nanopesticide prepared by the method according to any one of claims 1 to 6.
8. The application of the abamectin-LDHs composite nanopesticide prepared by the method according to any one of claims 1 to 6 in promoting plant growth.