Slow-release and controlled-release type nano pesticide, preparation method and application

Abstract

The invention provides a slow-release and controlled-release type nano pesticide, a preparation method and application. The slow-release and controlled-release type nano pesticide is an aqueous suspension taking water as a solvent, and the aqueous suspension comprises micro-nano hydroxyapatite, a copper preparation pesticide and chitosan. The copper preparation pesticide is adsorbed on the micro-nano hydroxyapatite, and the chitosan is at least partially coated on the surface of the copper preparation pesticide. Wherein the mass ratio of the micro-nano hydroxyapatite to the copper preparation pesticide to the chitosan is (50 to 100): (50 to 100): 1. The retention capacity of the nano pesticide in soil is improved, the slow release time is prolonged, the risk of loss along with rainwater leaching is smaller, and the utilization rate of the pesticide is improved in a green and environment-friendly mode. And moreover, phosphorus with a promoting effect on the growth of crops can be released for a long time, the application and waste of phosphate fertilizer are reduced, and great opportunity and prospect are shown as a multifunctional nano-carrier in the crop cultivation process.

Description

Technical Field

[0001] The present invention relates to the field of nano pesticides, and in particular to a sustained-release and controlled-release nano pesticide, a preparation method and an application thereof. Background Art

[0002] The application of pesticides is of great significance in agricultural production. However, with the long-term application of pesticides and agricultural development, most of the pesticides circulating in the market today have low application efficiency, poor stability of active ingredients, and easy loss with rainwater. In order to achieve the corresponding prevention and control effects, the amount of pesticides used is huge, causing environmental pollution and endangering food security. Therefore, improving the utilization rate of pesticides, enhancing the efficacy of pesticides, and reducing the loss of active ingredients are of great significance to agricultural production and people's safety.

[0003] Due to the importance of nitrogen and phosphorus to plant growth, phosphate fertilizer is of great significance to crop production. In addition, the amount of traditional phosphate fertilizer used in farmland is large and the utilization efficiency is low. The excessive use of phosphate fertilizer in farmland leads to the gradual accumulation of phosphorus in the environment. Controlling phosphorus in agricultural fertilizers can alleviate the phosphorus pressure in the environment to a certain extent, effectively reduce phosphorus input, and help achieve phosphorus control in the environment. The key to farmland phosphorus control is to improve the utilization efficiency of phosphate fertilizer and reduce phosphorus loss. Therefore, the development of nano-phosphate fertilizer with reduced use and reasonable planning provides a new idea for farmland phosphorus control.

[0004] Nanopesticides are listed as the first of the "Top Ten Emerging Chemical Technologies That Will Change the World". They are pesticides that use nano-preparation technology to make the active ingredients of pesticides stably dispersed in nanoscale in the formulation or / and the dispersion system used. The stability and controlled release process of nanopesticides can increase the utilization rate of active ingredients and thus reduce the amount of pesticides used, which is conducive to alleviating the burden of agricultural chemicals on the farmland environment and reducing the environmental risks and impacts of pesticide residues.

[0005] The sustained-release and controlled-release nanopesticides are mainly realized by the adsorption and desorption of the active ingredients on nanocarriers. The commonly used carriers currently studied are mainly silica, metal skeletons, graphene oxide, clay mineral materials, etc. However, most of them have the defects of high cost and only have the effects of sustained-release and controlled-release, and the effects are single. Summary of the invention

[0006] The main purpose of the present invention is to provide a sustained-release controlled-release nanopesticide, a preparation method and an application thereof, so as to solve the technical problems of the existing sustained-release controlled-release nanopesticides having high costs and relatively single effects.

[0007] To achieve the above object, the present invention provides a sustained-release controlled-release nanopesticide, wherein the sustained-release controlled-release nanopesticide is an aqueous suspension with water as a solvent, wherein the aqueous suspension comprises micro-nano hydroxyapatite, a copper pesticide and chitosan. The copper pesticide is adsorbed on the micro-nano hydroxyapatite, and the chitosan is at least partially coated on the surface of the copper pesticide.

[0008] The mass ratio of the micro-nano hydroxyapatite, the copper pesticide and the chitosan is (50-100):(50-100):1. Every 100 ml of the aqueous suspension contains 0.5-1 g of micro-nano hydroxyapatite.

[0009] According to an embodiment of the present application, the particle size of the micro-nano hydroxyapatite ranges from 20 nanometers to 80 micrometers.

[0010] According to an embodiment of the present application, the mass ratio of the micro-nano hydroxyapatite, the copper preparation pesticide and the chitosan is (50-100):(50-100):1.

[0011] According to an embodiment of the present application, the copper preparation pesticide is at least one of Bordeaux mixture, copper hydroxide pesticide preparation, and thiophanate-methyl preparation.

[0012] The present application also provides a method for preparing the above-mentioned sustained-release controlled-release nanopesticide, comprising the following steps:

[0013] Dissolve chitosan in acetic acid solution and stir at 30-40° C. to obtain a chitosan solution.

[0014] The copper pesticide is dropped into the micro-nano hydroxyapatite suspension and mixed to obtain a mixed liquid.

[0015] The chitosan solution is added dropwise to the mixed liquid and reacted for 1 hour to obtain the sustained-release and controlled-release nanopesticide.

[0016] The mass ratio of the micro-nano hydroxyapatite, the copper pesticide and the chitosan is (50-100):(50-100):1. Every 100 ml of the sustained-release controlled-release nanopesticide contains 0.5-1 g of micro-nano hydroxyapatite.

[0017] According to an embodiment of the present application, the concentration of the acetic acid solution is 2 mol / L.

[0018] According to an embodiment of the present application, the method for preparing the micro-nano hydroxyapatite suspension comprises:

[0019] Every 0.5-1g of micro-nano hydroxyapatite is mixed with 75mL of water, and stirred for 30min-1h at room temperature and a stirring speed of 300-500r / min to prepare a micro-nano hydroxyapatite suspension.

[0020] According to the embodiment of the present application, the step of adding the copper pesticide to the micro-nano hydroxyapatite suspension and mixing the mixture comprises:

[0021] The copper pesticide is added dropwise to the micro-nano hydroxyapatite suspension at a rate of 2 mL / min. After all the addition is completed, magnetic stirring is performed for 30 min to 1 h.

[0022] According to an embodiment of the present application, in the step of adding the chitosan solution dropwise into the mixed liquid and reacting for 1 hour, the dropping speed is 1 mL / min and the reaction time is 1 hour.

[0023] Application of the above-mentioned slow-release controlled-release nanopesticide or the slow-release controlled-release nanopesticide obtained by the above-mentioned preparation method in agricultural production.

[0024] In the above-mentioned slow-release controlled-release nanopesticides, micro-nano hydroxyapatite and copper pesticides are integrated with each other, and copper pesticides are fixed under the adsorption and chelation of various groups on the surface of micro-nano hydroxyapatite, thereby forming nanopesticides; and then the slow-release coating formed by chitosan utilizes the hydrogen bonds, electrostatic interactions and other forces between chitosan and pesticides to achieve slow release and dissolution of copper, and the retention capacity of nanopesticides in the soil is improved, the slow release time is extended, and the risk of loss due to leaching with rainwater is reduced, thereby improving the utilization rate of pesticides in a green and environmentally friendly way. In addition, it can also release phosphorus that promotes the growth of crops for a long time, reduce the application and waste of phosphorus fertilizers, and show great opportunities and prospects as a multifunctional nanocarrier in the process of crop cultivation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0026] Figure 1 The transmission electron microscope images of the micro-nano hydroxyapatite and the sustained-release controlled-release nanopesticide in Example 1, wherein (A) is the TEM image of the 60-nanometer rod-shaped hydroxyapatite, and (B) is the TEM image of the 60-nHAP-nCu in Example 1;

[0027] Figure 2The graph is a comparison of the copper release curves of nano-copper nano-pesticide (nHAP-nCu) suspensions of different sizes over time in Example 5;

[0028] Figure 3 This is a comparison of the copper release curves of inorganic copper nanopesticide (nHAP-ICu) suspensions of different sizes over time in Example 6;

[0029] Figure 4 It is a comparison chart of the copper release curves of different sizes of thiophanate-copper nanopesticide (nHAP-OCu) suspensions over time in Example 7;

[0030] Figure 5 This is a schematic diagram of a cross section of a soil column suitable for evaluating the copper sustained-release performance of a novel copper nanopesticide during the leaching process proposed by the present invention in Example 8;

[0031] Figure 6 is a bar graph of the copper content in the upper layer of the soil column after the leaching experiment in Example 8;

[0032] Figure 7 This is a bar graph of the copper content in the lower layer of the soil column after the leaching experiment in Example 8.

[0033] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that all directional indications (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0036] In addition, in the present invention, the descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0037] Furthermore, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0038] The present invention provides a sustained-release controlled-release nanopesticide, which is an aqueous suspension with water as a solvent, and the aqueous suspension includes micro-nano hydroxyapatite, copper preparation pesticide and chitosan. The copper preparation pesticide is adsorbed on the micro-nano hydroxyapatite, and the chitosan is at least partially coated on the surface of the copper preparation pesticide.

[0039] The mass ratio of the micro-nano hydroxyapatite, the copper pesticide and the chitosan is (50-100):(50-100):(1). Each milliliter of the aqueous suspension contains 0.005 g of micro-nano hydroxyapatite.

[0040] The main raw materials of the sustained-release controlled-release nanopesticide of the present application include micro-nano hydroxyapatite, copper preparation pesticide and chitosan.

[0041] Micro-nano hydroxyapatite is used as a pesticide carrier, and copper pesticides are adsorbed onto micro-nano hydroxyapatite through the adsorption and chelation of micro-nano hydroxyapatite suspension. The sustained-release coating formed by chitosan fully or partially covers the copper pesticides by utilizing the hydrogen bonds, electrostatic interactions and other forces between chitosan and copper pesticides, thereby achieving sustained release and dissolution of copper.

[0042] Micro-nano hydroxyapatite is used as raw material, which has low cost, large storage capacity, and is environmentally friendly. It can release phosphorus for a long time, which promotes the growth of crops, reduce the application and waste of phosphorus fertilizers, and shows great opportunities and prospects as a multifunctional nanocarrier in the process of crop cultivation.

[0043] In addition, the applicable micro-nano hydroxyapatite has a wide range of particle sizes. In some embodiments, the particle size of the micro-nano hydroxyapatite ranges from 20 nanometers to 80 micrometers. Exemplarily, the micro-nano hydroxyapatite includes particle shapes and needle-shaped hydroxyapatite with sizes of 20 nanometers, 60 nanometers and 80 micrometers.

[0044] The migration behaviors of sustained-release and controlled-release nanopesticides prepared from micro-nano hydroxyapatite with different particle sizes in soil are significantly different.

[0045] Copper pesticides are a type of broad-spectrum antimicrobial pesticides that are mainly used to combat bacterial and fungal plant diseases. Compared with other antimicrobial pesticides, copper pesticides can enhance their antimicrobial properties by promoting plant growth and enhancing the ability of plants to fight diseases, while copper ions can damage bacterial cells. In addition, compared with other organic antimicrobial pesticides, copper pesticides are less harmful to the human body and are low-toxic pesticides.

[0046] Therefore, the slow-release controlled-release nanopesticide of the present application selects copper preparation pesticide as pesticide, in addition to having the long-acting, slow-release effect of general slow-release pesticide, due to the slow release of copper ions, the concentration of copper ions is at a more reasonable level, so that plant growth can be better promoted and the ability of plants to resist diseases can be enhanced. Exemplarily, compared with the direct application of copper preparation pesticides of the same concentration, the slow-release controlled-release nanopesticide of the present application reduces the free copper concentration directly in contact with the plant when applied in the rhizosphere of the plant, thereby helping the plant to grow. That is, the slow-release controlled-release nanopesticide of the present application not only reduces the plant toxicity caused by excessive copper stress, but also has the long-term performance in the soil, which is conducive to killing a variety of pathogenic bacteria.

[0047] In some embodiments, the copper pesticide is at least one of Bordeaux mixture, copper hydroxide pesticide preparation, and thiophanate-methyl preparation.

[0048] Bordeaux mixture, copper hydroxide pesticide preparations, and thiophanate-methyl preparations are copper-based antibacterial pesticides, which are commercial antibacterial pesticides and can be purchased commercially. Bordeaux mixture developed by American Sannong Co., Ltd., Cosmet 3000 pesticide (the active ingredient is copper hydroxide) developed by American DuPont, and thiophanate-methyl preparations developed by Zhejiang Longwan Chemical Co., Ltd. In actual application, they are mainly used for bacterial plant diseases. Through the slow-release preparation process adopted in this patent, their long-term use can be enhanced and help plant growth.

[0049] This application uses chitosan as the coating material. Chitosan is not easily soluble in water and is more stable when used in soil environments. It has also been reported to have antibacterial properties, which is more advantageous for the application of antibacterial nanopesticides. In some related technologies, chitosan solution is used as the coating material.

[0050] Chitosan is extracted from the shells of crustaceans or the cell walls of fungi and is a natural high molecular weight polysaccharide. Chitosan is insoluble in water but soluble in weak acid. Compared with sodium alginate, it is more stable when used in soil environments. Chitosan has been reported to have certain antibacterial properties and has advantages in the preparation of antibacterial pesticides.

[0051] This application creates a green and friendly new dual-effect nanopesticide by constructing micro-nano hydroxyapatite as a pesticide carrier and loading different types of copper-based pesticides. Different types of copper-based pesticides, carrier micro-nano hydroxyapatite and chitosan medium are effectively combined to prepare a new type of green and efficient nanopesticide that can slowly release Cu / P nutrient elements. The above-mentioned slow-release controlled-release nanopesticide can simultaneously release two nutrient elements, copper and phosphorus.

[0052] In the above-mentioned slow-release controlled-release nanopesticides, micro-nano hydroxyapatite and copper pesticides are integrated with each other, and copper pesticides are fixed under the adsorption and chelation of various groups on the surface of micro-nano hydroxyapatite, thereby forming nanopesticides; and then the slow-release coating formed by chitosan utilizes the hydrogen bonds, electrostatic interactions and other forces between chitosan and pesticides to achieve slow release and dissolution of copper, and the retention capacity of nanopesticides in the soil is improved, the slow release time is extended, and the risk of loss due to leaching with rainwater is reduced, thereby improving the utilization rate of pesticides in a green and environmentally friendly way. In addition, it can also release phosphorus that promotes the growth of crops for a long time, reduce the application and waste of phosphorus fertilizers, and show great opportunities and prospects as a multifunctional nanocarrier in the process of crop cultivation.

[0053] In some embodiments, the mass ratio of the micro-nano hydroxyapatite, the copper preparation pesticide and the chitosan is 100:100:1.

[0054] Compared with the prior art, the advantages of the present invention are:

[0055] 1. In the above-mentioned slow-release controlled-release nanopesticides, the copper-prepared pesticide is loaded on micro-nano hydroxyapatite, with a large loading amount and good slow-release effect of copper ions, thus reducing the damage to crops caused by excessive copper concentration.

[0056] 2. The technical solution provided by the present invention uses hydroxyapatite as raw material, which has low cost, large storage capacity, and is environmentally friendly. It can release phosphorus that promotes the growth of crops for a long time, reduce the application and waste of phosphorus fertilizers, and show great opportunities and prospects as a multifunctional nanocarrier in the process of crop cultivation.

[0057] 3. In the above-mentioned sustained-release controlled-release nanopesticide, micro-nano hydroxyapatite is loaded with copper-prepared nanopesticide. When the pesticide and micro-nano hydroxyapatite are fused with each other, the pesticide is fixed with the copper-prepared pesticide under the adsorption and chelation of various groups on the surface of the micro-nano hydroxyapatite, thereby forming a nanopesticide. Then, a sustained-release coating film formed by chitosan is used to achieve the sustained release and dissolution of copper by utilizing the hydrogen bonds, electrostatic interactions and other forces between chitosan and pesticides. The retention capacity of nanopesticides in the soil is improved, the slow release time is extended, and the risk of loss due to leaching with rainwater is reduced, thereby improving the utilization rate of pesticides in a green and environmentally friendly way.

[0058] The present application also provides a method for preparing the above-mentioned sustained-release controlled-release nanopesticide, comprising the following steps:

[0059] S100: dissolving chitosan in acetic acid solution, stirring at 30-40° C. to obtain a chitosan solution.

[0060] The concentration of the chitosan solution is 1 g / L. For example, 0.05 g of chitosan powder is weighed and dissolved in 50 mL of acetic acid solution, and magnetically stirred at 30-40° C. for 2 h to obtain a chitosan solution. In some embodiments, the concentration of the acetic acid solution is 2 mol / L.

[0061] S200: Add the copper pesticide dropwise into the micro-nano hydroxyapatite suspension, mix well, and obtain a mixed liquid.

[0062] The copper-prepared pesticide is at least one of Bordeaux mixture, copper hydroxide pesticide preparation, and thiophanate-methyl preparation.

[0063] In some embodiments, the copper hydroxide pesticide formulation is Copper Hydroxide Trichlorfon.

[0064] In some embodiments, the thiophanate-methyl preparation is a thiophanate-methyl preparation with a concentration of 80%.

[0065] In some embodiments, the step of adding the copper pesticide to the micro-nano hydroxyapatite suspension and mixing the mixture comprises:

[0066] The copper pesticide is added dropwise to the micro-nano hydroxyapatite suspension at a rate of 20 to 40 drops / min. After all the addition is completed, magnetic stirring is performed for 30 minutes to 1 hour.

[0067] For example, at room temperature, under magnetic stirring at 300-500 r / min, 20 mL of the 3-copper pesticide solution of step 2) is slowly added to the micro-nano hydroxyapatite solution, and after all the addition is completed, magnetic stirring is performed for 30 min to 1 h.

[0068] In some embodiments, the method for preparing the micro-nano hydroxyapatite suspension comprises:

[0069] 0.5-1g of micro-nano hydroxyapatite is mixed with 75mL of water, and stirred for 30min-1h at room temperature and a stirring speed of 300-500r / min to prepare a micro-nano hydroxyapatite suspension.

[0070] S300: Add the chitosan solution dropwise to the mixed liquid and react for 1 hour to obtain the sustained-release controlled-release nanopesticide. The mass ratio of the micro-nano hydroxyapatite, the copper pesticide and the chitosan is (50-100):(50-100):(50-100). Every 100 ml of the sustained-release controlled-release nanopesticide contains 0.05 g of micro-nano hydroxyapatite.

[0071] In some embodiments, in the step of adding the chitosan solution dropwise to the mixed liquid and reacting for 1 hour, the dropping speed is 20 to 40 drops / min and the reaction time is 1 hour.

[0072] The above-mentioned method for preparing the sustained-release controlled-release nanopesticide has a simple process, a large loading amount and mild conditions. The prepared sustained-release controlled-release nanopesticide has the same beneficial effects as the above-mentioned sustained-release controlled-release nanopesticide, which will not be described in detail.

[0073] Application of the above-mentioned slow-release controlled-release nanopesticide or the slow-release controlled-release nanopesticide obtained by the above-mentioned preparation method in agricultural production.

[0074] The above-mentioned slow-release controlled-release nanopesticide can be applied to the application scenario level of agricultural production. This application evaluates the slow-release and regularity of copper and phosphorus in the leaching process of this new type of nanopesticide in the soil application scenario. Based on the limitations of copper-based pesticides in the market, this application confirms that the slow-release process of copper in the slow-release controlled-release nanopesticide is conducive to reducing the plant toxicity caused by excessive copper stress, and the long-term effectiveness in the soil is conducive to killing a variety of pathogenic bacteria, and there are significant differences in their functions.

[0075] Embodiment 1:

[0076] The present embodiment provides a method for preparing a nano-hydroxyapatite-loaded copper hydroxide pesticide (nHAP-nCu): 0.52 g, 0.51 g, and 0.54 g of micro-nano hydroxyapatite with a size of 20 nm, 60 nm, and 80 um are placed in a 100 mL conical flask, respectively, and 75 mL of deionized water is added to mix, and then magnetically stirred at 400 r / min at room temperature for 2 h to prepare a hydroxyapatite suspension; 0.53 g, 0.51 g, and 0.54 g of the pesticide preparation of Kesaidi Sanqian are respectively weighed and dissolved in 20 mL of water, and magnetically stirred at 400 r / min at room temperature for 2 h. L, dropwise added into the micro-nano hydroxyapatite suspension at a speed of 100 g to obtain a micro-nano hydroxyapatite-loaded copper hydroxide nanopesticide suspension; then weighed 0.005 g of chitosan powder and dissolved in 5 mL of acetic acid solution, and magnetically stirred at 35°C for 2 h to obtain a chitosan solution; under 400 r / min magnetic stirring, added dropwise at a speed of 1 mL per minute into the micro-nano hydroxyapatite-loaded copper hydroxide nanopesticide suspension, and after the dropwise addition was completed, continued stirring at 400 r / min for 1 h to obtain a new type of nanopesticide (i.e., sustained-release nanopesticide nHAP-nCu) with a total volume of 100 mL that can long-term slow-release copper and phosphorus nutrients.

[0077] 60 nanometer rod-shaped hydroxyapatite and the sustained-release nanopesticide prepared from 60 nanometer hydroxyapatite were analyzed by transmission electron microscopy. The results are as follows: Figure 1 As shown, Figure 1 : (A) is the TEM image of 60-nanometer rod-shaped hydroxyapatite, and (B) is the TEM image of the sustained-release nanopesticide 60-nHAP-nCu in Example 1.

[0078] Embodiment 2:

[0079] The present embodiment provides a method for preparing a micro-nano hydroxyapatite-loaded copper sulfate nanopesticide (nHAP-ICu): 0.52 g, 0.51 g, and 0.54 g of hydroxyapatite with a size of 20 nm, 60 nm, and 80 um are placed in a 100 mL conical flask, respectively, and 75 mL of deionized water is added to mix, and then magnetically stirred at 400 r / min at room temperature for 2 h to prepare a micro-nano hydroxyapatite suspension; 0.53 g, 0.51 g, and 0.54 g of Bordeaux mixture pesticide preparation are respectively weighed and dissolved in 20 mL of water, and magnetically stirred at 400 r / min at room temperature for 2 h. L, dropwise added into the micro-nano hydroxyapatite suspension at a speed of 1 mL / min to obtain a micro-nano hydroxyapatite-loaded copper sulfate nanopesticide suspension; then weighed 0.005 g of chitosan powder and dissolved in 5 mL of acetic acid solution, and magnetically stirred at 35°C for 2 h to obtain a chitosan solution; under 400 r / min magnetic stirring, added dropwise at a speed of 1 mL / min into the micro-nano hydroxyapatite-loaded copper sulfate nanopesticide suspension, and after the dropwise addition was completed, continued stirring at 400 r / min for 1 h to obtain a new type of nanopesticide (i.e., sustained-release nanopesticide nHAP-ICu) with a total volume of 100 mL that can long-term slow-release copper and phosphorus nutrients.

[0080] Embodiment 3:

[0081] The present embodiment provides a method for preparing a thiophanate-copper nanopesticide (nHAP-OCu) loaded on micro-nano hydroxyapatite: 0.52 g, 0.51 g, and 0.54 g of hydroxyapatite with a size of 20 nm, 60 nm, and 80 um are placed in a 100 mL conical flask, respectively, and 75 mL of deionized water is added to mix, and then magnetically stirred at 400 r / min at room temperature for 2 h to prepare a micro-nano hydroxyapatite suspension; 2.1 mL, 2.0 mL, and 2.2 mL of thiophanate-copper pesticide preparation are respectively measured and dissolved in 20 mL of water, and magnetically stirred at 400 r / min at room temperature for 2 h. L, dropwise added into the micro-nano hydroxyapatite suspension at a speed of 1 mL / min to obtain a micro-nano hydroxyapatite-loaded thiophanate-copper nanopesticide suspension; then weighed 0.005 g of chitosan powder and dissolved in 5 mL of acetic acid solution, and magnetically stirred at 35°C for 2 h to obtain a chitosan solution; under 400 r / min magnetic stirring, added dropwise at a speed of 1 mL / min to the micro-nano hydroxyapatite-loaded thiophanate-copper nanopesticide suspension, and after the dropwise addition was completed, continued stirring at 400 r / min for 1 h to obtain a new type of nanopesticide (i.e., sustained-release nanopesticide nHAP-OCu) with a total volume of 100 mL that can long-term slow-release copper and phosphorus nutrients.

[0082] Example 4: Standard solutions with copper concentrations of 0.5 mg / L, 1 mg / L, 2 mg / L, 5 mg / L, 10 mg / L and 20 mg / L were prepared, the absorbance values ​​of copper solutions of different concentrations were tested by flame atomic absorption spectrometer, standard curves were drawn, the relationship between sample absorbance and copper concentration was established, and a method for determining the copper concentration of different sample solutions was constructed.

[0083] Embodiment 5:

[0084] The newly prepared copper hydroxide nanopesticide (nHAP-nCu) in Example 1 was allowed to stand for stratification, and the supernatant was taken after standing for 0 days, 1 day, 2 days, 5 days and 10 days, and the supernatant was centrifuged at a speed of 5000r / min for 10 minutes. The supernatant was filtered through a 0.45 micron microporous filter membrane, and the absorbance of the samples under a copper lamp light source was tested by flame atomic absorption spectroscopy. The change of copper concentration in the copper hydroxide nanopesticide (nHAP-nCu) suspension over time was calculated according to the copper concentration standard curve in the aqueous solution provided in Example 4, and the change of copper ion release over time in the prepared copper hydroxide nanopesticide (nHAP-nCu) of different sizes and the original pesticide of Keshade Sanqian (i.e., the control group, ck group) was compared. The nanopesticides loaded with three different sizes of micro-nano hydroxyapatite can release more copper ions in the suspension, and have a significant improvement compared with the unloaded Keshade pesticide. The copper release concentration of nanopesticides with sizes of 60nm and 80μm is higher, about 700mg / L. The difference in copper release over time of copper hydroxide nanopesticides of different sizes is as follows Figure 2 shown.

[0085] Embodiment 6:

[0086] The newly prepared copper sulfate nano pesticide suspension nHAP-ICu in Example 2 was allowed to stand for stratification, and the supernatant was drawn after standing for 0 days, 1 day, 2 days, 5 days and 10 days, and the supernatant was centrifuged at a speed of 5000r / min for 10 minutes. The supernatant was taken and the absorbance of the sample under the copper lamp light source was tested by flame atomic absorption spectroscopy. The change of copper concentration in the copper sulfate nano pesticide suspension nHAP-ICu over time was calculated according to the copper concentration standard curve in the aqueous solution provided in Example 4, and the change of copper ion release over time in the prepared copper sulfate nano pesticide (nHAP-ICu) of different sizes and Bordeaux mixture pesticide was compared. It can be seen from the calculation that the Bordeaux mixture pesticide without nanocarrier loading can basically not release copper ions in the suspension, and needs to be used together with other agents in the actual use process to release copper ions with bactericidal effect. After being loaded with three different sizes of micro-nano hydroxyapatite, the nanopesticides were able to release more copper ions in the suspension, and the copper release effect of the nanopesticide with a size of 60nm was better than that of the nanopesticides with a size of 20nm and 80μm. Figure 3 shown.

[0087] Embodiment 7:

[0088] The newly prepared thiophanate-copper nanopesticide (nHAP-OCu) suspension of Example 3 was allowed to stand for stratification, and the supernatant was taken after standing for 0 days, 1 day, 2 days, 5 days and 10 days, and the supernatant was centrifuged at a speed of 5000r / min for 10 minutes. The supernatant was taken and the absorbance of the sample under the copper lamp light source was tested by flame atomic absorption spectroscopy. The change of the copper concentration in the thiophanate-copper nanopesticide (nHAP-OCu) and the thiophanate-copper nanopesticide over time was calculated according to the copper concentration standard curve in the aqueous solution provided in Example 4, and the change of the copper ion release over time in the prepared thiophanate-copper nanopesticide (nHAP-OCu) of different sizes was compared. It can be seen from the calculation that the copper hydroxide nanopesticide without nanocarrier loading can release 300-500mg / L of copper ions in the suspension, and the copper concentration increases slowly with time. Calculations show that the copper concentration released from the original thiophanate-copper pesticide that has not been loaded with micro-nano hydroxyapatite first decreases and then increases over time, and the copper concentration released from the three different sizes of thiophanate-copper nanopesticides is obviously very low, which indicates that under the strong interaction on the surface of the nanopesticide, the thiophanate-copper pesticide and the hydroxyapatite nanocarrier are organically chelated. The difference in copper release over time from thiophanate-copper nanopesticides of different sizes is shown in Figure 2. Figure 4 shown.

[0089] Example 8

[0090] This example provides an application method of copper sulfate nanopesticide loaded with micro-nano hydroxyapatite. The retention and release performance of the three types of copper preparation nanopesticide loaded with micro-nano hydroxyapatite prepared in Example 1, Example 2, and Example 3 in soil were compared by leaching experiments. Figure 1 When applied in the soil, a soil column with a height of 10 cm and a cross-section of 5 cm in diameter was used for leaching to test the performance of copper hydroxide nanopesticide in releasing copper in the soil. 5 mL of ultrapure water was dripped onto the soil column every day. After 10 days of leaching experiments, the soil column was divided into 5 cm layers, and the upper and lower layers of the soil column were collected. XRF was used to detect the difference in copper content in the upper and lower layers of soil. The copper content detected in the upper soil layer is as follows: Figure 6 As shown in Figure 2, the total amount of copper retained by the loaded nanopesticide in the upper soil layer is greater than that of the original pesticide. The copper content detected in the lower soil layer is as follows: Figure 7 As shown, the results showed that during the leaching process of 60nm and 80um loaded copper hydroxide nanopesticides, the copper content in the lower layer of soil did not increase, indicating that the use of 60nm and 80um loaded copper preparations to prepare nanopesticides can significantly reduce the risk of copper loss during leaching.

[0091] It can be seen that the new nanopesticide of the present invention has been tested and verified for copper slow release and phosphorus slow release during soil application. Compared with existing pesticides, copper slow release effect is better, less loss with water erosion, and can slowly release phosphorus in the soil, increasing fertilizer efficiency and reducing the risk of nutrient waste, and has more beneficial effects on soil health and crop growth.

[0092] The above technical solutions of the present invention are only preferred embodiments of the present invention, and the patent scope of the present invention is not limited thereto. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A sustained-release controlled-release nanopesticide, characterized in that: The sustained-release controlled-release nanopesticide is an aqueous suspension with water as solvent, and the aqueous suspension includes micro-nano hydroxyapatite, copper pesticide and chitosan; the copper pesticide is adsorbed on the micro-nano hydroxyapatite, and the chitosan is at least partially coated on the surface of the copper pesticide; The mass ratio of the micro-nano hydroxyapatite, the copper pesticide and the chitosan is (50-100):(50-100):1; and every 100 ml of the aqueous suspension contains 0.5-1 g of micro-nano hydroxyapatite.

2. The sustained-release controlled-release nanopesticide according to claim 1, characterized in that: The particle size of the micro-nano hydroxyapatite ranges from 20 nanometers to 80 micrometers.

3. The sustained-release controlled-release nanopesticide according to claim 1, characterized in that: The mass ratio of the micro-nano hydroxyapatite, the copper preparation pesticide and the chitosan is 100:100:

1.

4. The sustained-release controlled-release nanopesticide according to any one of claims 1 to 3, characterized in that: The copper preparation pesticide is at least one of Bordeaux mixture, copper hydroxide pesticide preparation, and thiophanate-methyl preparation.

5. A method for preparing a sustained-release controlled-release nanopesticide as claimed in claim 1, characterized in that: The following steps are involved: Dissolve chitosan in acetic acid solution and stir at 30-40° C. to obtain a chitosan solution; Adding the copper pesticide dropwise into the micro-nano hydroxyapatite suspension, mixing well, and obtaining a mixed liquid; Adding the chitosan solution dropwise into the mixed liquid and reacting for 1 hour to obtain the sustained-release controlled-release nanopesticide; The mass ratio of the micro-nano hydroxyapatite, the copper pesticide and the chitosan is (50-100):(50-100):1; and every 100 ml of the sustained-release controlled-release nano pesticide contains 0.5-1 g of micro-nano hydroxyapatite.

6. The preparation method according to claim 5, characterized in that: The concentration of the acetic acid solution is 2 mol / L.

7. The preparation method according to claim 5, characterized in that: The preparation method of the micro-nano hydroxyapatite suspension comprises: Every 0.5-1g of micro-nano hydroxyapatite is mixed with 75mL of water, and stirred for 30min-1h at room temperature and a stirring speed of 300-500r / min to prepare a micro-nano hydroxyapatite suspension.

8. The preparation method according to claim 5, characterized in that: The step of adding the copper pesticide dropwise to the micro-nano hydroxyapatite suspension and mixing the mixture comprises: The copper pesticide is added dropwise to the micro-nano hydroxyapatite suspension at a rate of 2 mL / min. After all the addition is completed, magnetic stirring is performed for 30 min to 1 h.

9. The preparation method according to any one of claims 5 to 8, characterized in that: In the step of adding the chitosan solution dropwise into the mixed liquid and reacting for 1 hour, the dropping speed is 1 mL / min and the reaction time is 1 hour.

10. Use of the sustained-release controlled-release nanopesticide according to any one of claims 1 to 4 or the sustained-release controlled-release nanopesticide obtained by the preparation method according to any one of claims 5 to 9 in agricultural production.

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