Pesticide preparation based on nanocellulose porous metal framework load and preparation method thereof

Abstract

The invention relates to a preparation method of a pesticide preparation loaded on the basis of a nanocellulose porous metal framework, which comprises the following steps: (1) adding polyvinyl alcohol into dimethyl sulfoxide, and heating for reaction to obtain a solution A; adding zinc nitrate hexahydrate into methanol, and carrying out ultrasonic treatment and stirring until the zinc nitrate hexahydrate is fully dissolved to obtain a solution B; dissolving 2-methylimidazole and a pesticide in methanol to obtain a solution C; (2) adding cellulose nanocrystals into the solution A, carrying out heating reaction, and cooling after the reaction to obtain nanocellulose gel; fully mixing the solution B and the solution C, performing ultrasonic treatment, performing heating reaction, and performing centrifugal washing to obtain a pesticide-loaded porous metal framework material; and (3) mixing the porous metal framework loading material and the nanocellulose gel, transferring the mixture to a high-shear mixer for homogenization treatment, and then performing centrifugal washing and cold drying to obtain the pesticide preparation. The pesticide preparation disclosed by the invention is high in pesticide loading rate and high in encapsulation efficiency, and can realize slow release and pH responsiveness of the pesticide.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of composite materials, and particularly relates to a pesticide preparation based on a nano-cellulose porous metal framework and a preparation method thereof. BACKGROUND

[0002] Crop diseases and pests are one of the main factors affecting grain yield and quality, especially under the background of climate change and globalization, new pests and pathogens are constantly emerging, and without sufficient pesticide protection, the yield of many crops may be greatly reduced or even lost, thereby threatening food security. Pesticides can effectively control pests, pathogens, weeds and the like, and help to reduce their damage to crops, but in the practical application of pesticides, more than 90% of the pesticides are ineffective on target crops and will be lost through volatilization, spray drift, photolysis, leaf sliding, rainwater leaching and the like. In addition, excessive and unreasonable use of these pesticides will seriously affect food safety and target biological resistance. These problems will gradually lead to the destruction of the ecosystem and environmental pollution, and ultimately threaten human health. Therefore, it is necessary to develop an environmentally responsive pesticide controlled-release preparation to maintain the long-term efficacy of the pesticide and minimize the potential risk to the ecological environment.

[0003] The specific surface area of the traditional pesticide carrier is small, which cannot efficiently adsorb or carry a large number of pesticide molecules, thereby limiting its loading capacity; and the pesticide cannot be released or controlled, which leads to rapid release of the pesticide, thereby accelerating its degradation or volatilization, and the effect is short-term and difficult to last. SUMMARY

[0004] Based on the above-mentioned shortcomings and deficiencies in the prior art, one of the purposes of the present application is to at least solve one or more of the above-mentioned problems in the prior art, in other words, one of the purposes of the present application is to provide a pesticide preparation based on a nano-cellulose porous metal framework and a preparation method thereof, which meets one or more of the aforementioned needs, utilizes the instability of the porous metal framework under acidic conditions and the natural environmental protection and drug loading characteristics of nano-cellulose to prepare a nano-cellulose porous metal framework, and constructs a pH environment-responsive pesticide release system to achieve targeted and on-demand release of the pesticide.

[0005] In order to achieve the above-mentioned purposes of the application, the following technical solutions are adopted in the present application:

[0006] The preparation method of the pesticide preparation based on the nano-cellulose porous metal framework comprises the following steps:

[0007] (1) adding polyvinyl alcohol to dimethyl sulfoxide and heating to react to obtain solution A;

[0008] adding zinc nitrate hexahydrate to methanol, ultrasonicating and stirring until fully dissolved to obtain solution B;

[0009] 2-Methylimidazole and the pesticide are dissolved in methanol, and this solution is denoted as solution C.

[0010] (2) Add cellulose nanocrystals to solution A and heat to react. After the reaction, cool to obtain nanocellulose gel.

[0011] After thoroughly mixing solutions B and C, the mixture was ultrasonicated, heated to react, and then centrifuged and washed to obtain a porous metal framework material loaded with pesticides.

[0012] (3) The porous metal framework loading material and nanocellulose gel are mixed and transferred to a high shear mixer for homogenization. Then, the mixture is centrifuged, washed, and cooled to obtain the pesticide formulation.

[0013] As a preferred embodiment, in step (1), the solid-liquid ratio of polyvinyl alcohol to dimethyl sulfoxide is 1g:(5-6)mL, and the reaction time is 10-15min at a temperature of 95-100℃ to obtain solution A.

[0014] As a preferred embodiment, in step (1), the solid-liquid ratio of zinc nitrate hexahydrate to methanol in solution B is 1g:(30-50)mL.

[0015] As a preferred embodiment, in step (1), the solid-liquid ratio of 2-methylimidazole to methanol in solution C is 1g:(20-25)mL, and the solid-liquid ratio of pesticide to methanol is 1g:(40-60)mL.

[0016] As a preferred embodiment, the pesticide is acetamiprid, pyrazoline, thiophanate-methyl, or triazophos.

[0017] As a preferred embodiment, in step (2), the solid-liquid ratio of cellulose nanocrystals to solution A is 1g:(10-15)mL, and the reaction time is 30-40min at a temperature of 80-100℃.

[0018] As a preferred embodiment, in step (2), solution B and solution C are thoroughly mixed and then sonicated for 5-10 minutes, followed by a reaction time of 4-10 hours at a temperature of 50-60°C.

[0019] As a preferred embodiment, in step (3), the mass ratio of the porous metal framework loading material to the nanocellulose gel is 1:(1-1.5), the homogenization treatment speed is 9000-10000 rpm, and the duration is 5-7 min.

[0020] As a preferred embodiment, in step (3), the centrifugal washing speed is 1000-2000 rpm and the cold drying time is 24-32 h.

[0021] The present invention also provides pesticide formulations based on porous metal frameworks of nanocellulose prepared by the preparation method described in any of the preceding embodiments.

[0022] Compared with the prior art, the beneficial effects of this invention are:

[0023] (1) This invention uses cellulose nanocrystals (CNC) and zinc-based organic frameworks as raw materials and synthesizes nanocellulose porous metal frameworks by in-situ growth method. Cellulose nanocrystals have a high specific surface area, thus providing more active sites and improving drug loading capacity. Zinc-based organic frameworks (Zn-MOFs) have rich pore structure, protecting pesticide molecules from the influence of the external environment, realizing the slow release of pesticides, and effectively prolonging the action time of pesticides.

[0024] (2) The nanoscale size of the cellulose nanocrystals (CNC) of the present invention gives it an extremely high specific surface area, which provides more space for pesticide loading; the high specific surface area allows CNC to adsorb more pesticide molecules, thereby increasing the pesticide loading capacity. Its surface has a large number of hydroxyl groups, which can bind to pesticide molecules through non-covalent forces such as hydrogen bonds and van der Waals forces, further enhancing the loading efficiency; by controlling the release rate of pesticides, CNC can reduce the contact between pesticides and the environment and non-target organisms, and reduce the acute toxicity of pesticides; in addition, as a natural and low-toxicity material, CNC can reduce the potential harm of pesticides to humans and animals.

[0025] (3) Zinc-based organic frameworks (Zn-MOFs) are a class of porous crystalline materials composed of zinc ions and organic ligands through coordination bonds. They possess high specific surface area and abundant pore structure. Their dodecahedral structure can protect pesticide molecules from the influence of the external environment, preventing pesticide decomposition and inactivation during storage and application. Furthermore, they can achieve slow release of pesticides, effectively prolonging the duration of action of pesticides in the target area. Zn-MOFs also provide insights for designing pH-responsive controlled-release formulations because, under acidic conditions, Zn... 2+ -Imidazole ion coordination bonds are easily broken, giving it acid-responsive properties, which allows it to achieve the advantage of pH-responsive pesticides and can be widely used in agricultural pharmaceuticals and other fields. Attached Figure Description

[0026] Figure 1 The images shown are scanning electron microscope (SEM) images (a, b, c) and particle size distribution diagrams (d, e, f) of the pesticide formulations of Comparative Example 1, Example 1, and Comparative Example 2 of this invention.

[0027] Figure 2 This is a diagram illustrating the chemical bonding mechanism of the nanocellulose porous metal framework material of Example 1 of the present invention;

[0028] Figure 3This is a bar chart comparing the pesticide loading rate and encapsulation rate of pesticide formulations in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0029] Figure 4 This is a bar chart comparing the pesticide loading rate and encapsulation rate of the pesticide formulations in Example 1 and Comparative Example 3 of the present invention.

[0030] Figure 5 This is a comparison chart of pesticide residue rates after spraying with rainwater at different times, based on the pesticide formulation, commercial pesticide, and acetamiprid stock solution of Example 1 of the present invention.

[0031] Figure 6 The images show the insecticidal effects (a), insecticidal rate (b), and median lethal concentration (c) of the pesticide formulation, commercial pesticide, and acetamiprid stock solution in Example 1 of this invention.

[0032] Figure 7 The images show the release curves (a) of the pesticide formulation of Example 1 of the present invention at different pH values, and the fitted curves (b, c, d) of the Ritger-Peppas release kinetic model. Detailed Implementation

[0033] The technical solution of the present invention will be further explained and illustrated below through specific embodiments.

[0034] Example 1:

[0035] The method for preparing pesticide formulations based on porous metal frameworks of nanocellulose in this embodiment includes the following steps:

[0036] 2g of polyvinyl alcohol was added to 10mL of dimethyl sulfoxide solution and heated at 95℃ for 10min to obtain solution A. 1g of cellulose nanocrystals was added to solution A and heated at 90℃ for 30min. The solution was then removed and cooled for 30min to gel, thus obtaining nanocellulose gel.

[0037] Dissolve 2.231 g of zinc nitrate hexahydrate in 100 mL of methanol solution, sonicate for 10 min, stir for 30 min until the solute is completely dissolved to obtain solution B;

[0038] 2.2463 g of 2-methylimidazole and 1 g of acetamiprid Ace were dissolved in 50 mL of methanol to obtain solution C;

[0039] After thoroughly mixing solutions B and C, the mixture was sonicated for 5 minutes and heated at 50°C for 6 hours. The mixture was then washed 5 times by centrifugation with methanol at a speed of 4500 rpm to obtain a porous metal framework material loaded with acetamiprid.

[0040] Cellulose nanocrystalline gel and porous metal framework material were added to a high-shear mixer at a mass ratio of 1:1, the speed was adjusted to 10,000 rpm, the shearing time was 6 min, and then the mixture was washed 5 times with deionized water at a centrifugation speed of 2000 rpm. After being cold-dried for 24 h, the pesticide formulation was obtained, denoted as CNC Gel-ZnMOFs.

[0041] Example 2:

[0042] The method for preparing pesticide formulations based on porous metal frameworks of nanocellulose in this embodiment includes the following steps:

[0043] Add 2g of polyvinyl alcohol to 12mL of dimethyl sulfoxide solution and heat at 100℃ for 15min to obtain solution A. Add 1g of cellulose nanocrystals to solution A and heat at 80℃ for 40min. Remove and cool for 30min to gel to obtain nanocellulose gel.

[0044] Dissolve 2g of zinc nitrate hexahydrate in 100mL of methanol solution, sonicate for 10min, stir for 30min until the solute is completely dissolved to obtain solution B;

[0045] Dissolve 2g of 2-methylimidazole and 1g of thiophanate-methyl in 50mL of methanol to obtain solution C;

[0046] After thoroughly mixing solutions B and C, the mixture was sonicated for 5 minutes and heated at 60°C for 4 hours. The mixture was then washed three times with deionized water at a centrifugation speed of 4000 rpm to obtain a porous metal framework material loaded with thiophanate-methyl.

[0047] Cellulose nanocrystalline gel and porous metal framework material were added to a high-shear mixer at a mass ratio of 1:1.2, the speed was adjusted to 9000 rpm, the shearing time was 7 min, and then the mixture was washed three times with deionized water at a centrifugation speed of 1000 rpm. After being cold-dried for 30 h, the pesticide formulation was obtained.

[0048] Example 3:

[0049] The method for preparing pesticide formulations based on porous metal frameworks of nanocellulose in this embodiment includes the following steps:

[0050] 2g of polyvinyl alcohol was added to 11mL of dimethyl sulfoxide solution and heated at 95℃ for 12min to obtain solution A. 1g of cellulose nanocrystals was added to solution A and heated at 100℃ for 35min. The solution was then removed and cooled for 30min to gel, resulting in nanocellulose gel.

[0051] Dissolve 3g of nitric acid hexahydrate in 100mL of methanol solution, sonicate for 10min, stir for 30min until the solute is completely dissolved to obtain solution B;

[0052] Dissolve 2.5 g of 2-methylimidazolium and 0.9 g of pyrazoline in 50 mL of methanol to obtain solution C;

[0053] After thoroughly mixing solutions B and C, the mixture was sonicated for 5 min and heated at 55 °C for 10 h. The mixture was then washed three times with methanol at a centrifugation speed of 4500 rpm to obtain a porous metal framework material loaded with pyrazoline.

[0054] Cellulose nanocrystalline gel and porous metal framework material were added to a high-shear mixer at a mass ratio of 1:1.5, the speed was adjusted to 9500 rpm, the shearing time was 5 min, and then the mixture was washed 5 times with deionized water at a centrifugation speed of 1500 rpm. After being cold-dried for 24 h, the pesticide formulation was obtained.

[0055] Example 4:

[0056] The method for preparing pesticide formulations based on porous metal frameworks of nanocellulose in this embodiment includes the following steps:

[0057] 2g of polyvinyl alcohol was added to 10mL of dimethyl sulfoxide solution and heated at 95℃ for 10min to obtain solution A. 1g of cellulose nanocrystals was added to solution A and heated at 90℃ for 30min. The solution was then removed and cooled for 30min to gel, thus obtaining nanocellulose gel.

[0058] Dissolve 2.231 g of nitric acid hexahydrate in 100 mL of methanol solution, sonicate for 10 min, stir for 30 min until the solute is completely dissolved to obtain solution B;

[0059] 2.2463 g of 2-methylimidazole and 1 g of triazophos were dissolved in 50 mL of methanol solution to obtain solution C;

[0060] After thoroughly mixing solutions B and C, the mixture was sonicated for 5 minutes and heated at 50°C for 6 hours. The mixture was then washed 5 times by centrifugation with methanol at a speed of 4500 rpm to obtain a porous metal framework material loaded with acetamiprid.

[0061] Cellulose nanocrystalline gel and porous metal framework material were added to a high-shear mixer at a mass ratio of 1:1, the speed was adjusted to 10,000 rpm, the shearing time was 6 min, and then the mixture was washed 5 times with deionized water at a centrifugation speed of 2000 rpm. After being cold-dried for 24 h, the pesticide formulation was obtained.

[0062] Comparative Example 1:

[0063] The pesticide formulation in this comparative example differs from that in Example 1 in that it does not contain nanocellulose gel.

[0064] The specific preparation process is as follows:

[0065] Dissolve 2.231g of zinc nitrate hexahydrate in 100mL of methanol solution, sonicate for 10min, stir for 30min until the solute is completely dissolved, and record this as solution A;

[0066] Dissolve 2.2463 g of 2-methylimidazole and 1 g of acetamiprid in 50 mL of methanol solution, and denote this as solution B;

[0067] Solution A and solution B were thoroughly mixed, sonicated for 5 minutes, heated at 50°C for 6 hours, washed five times with methanol at 4500 rpm, and then cooled and dried for 24 hours to obtain the pesticide formulation, denoted as ZnMOFs.

[0068] Comparative Example 2:

[0069] The pesticide formulation in this comparative example differs from that in Example 1 in that cellulose nanocrystals are directly added.

[0070] The specific preparation process is as follows:

[0071] Dissolve 2.231 g of zinc nitrate hexahydrate and 0.521 g of cellulose nanocrystals in 100 mL of methanol solution, sonicate for 10 min, stir for 30 min until the solutes are completely dissolved, and record this as solution A;

[0072] Dissolve 2.2463 g of 2-methylimidazole and 1 g of acetamiprid in 50 mL of methanol solution, and denote this as solution B;

[0073] After thoroughly mixing solutions A and B, the mixture was sonicated for 5 minutes and heated at 50°C for 6 hours. The mixture was then washed five times with methanol at a centrifugation speed of 4500 rpm and cooled for 24 hours to obtain the pesticide formulation, denoted as CNC-ZnMOFs.

[0074] Comparative Example 3:

[0075] The pesticide formulation in this comparative example differs from that in Example 1 in that the nanocellulose porous metal framework material is prepared by a one-step synthesis method and then loaded with pesticide.

[0076] The specific preparation process is as follows:

[0077] 2g of polyvinyl alcohol was added to 10mL of dimethyl sulfoxide solution and heated at 95℃ for 10min to obtain solution A. 1g of cellulose nanocrystals was added to solution A and heated at 90℃ for 30min. The solution was then removed and cooled for 30min to gel, thus obtaining nanocellulose gel.

[0078] Dissolve 2.231 g of zinc nitrate hexahydrate in 100 mL of methanol solution, sonicate for 10 min, stir for 30 min until the solute is completely dissolved to obtain solution B;

[0079] Dissolve 2.2463 g of 2-methylimidazole in 50 mL of methanol solution to obtain solution C;

[0080] After thoroughly mixing solutions B and C, the mixture was sonicated for 5 minutes and heated at 50°C for 6 hours. The mixture was then washed 5 times by centrifugation with methanol at a speed of 4500 rpm to obtain a porous metal framework material.

[0081] Cellulose nanocrystalline gel and porous metal framework material were added to a high-shear mixer at a mass ratio of 1:1, the speed was adjusted to 10,000 rpm, the shearing time was 6 min, and then the mixture was washed 5 times with deionized water at a centrifugation speed of 2000 rpm. After being air-dried for 24 h, the nanocellulose porous metal framework material was obtained.

[0082] The nanocellulose porous metal framework material and 1g of acetamiprid were added to 100mL of methanol solution and heated at 50℃ for 6h. The mixture was washed 5 times by centrifugation with methanol at a speed of 4500rpm and dried to obtain the nanocellulose porous metal framework material directly loaded with pesticide.

[0083] The pesticide formulations of the above embodiments and comparative examples are characterized and tested in the following details:

[0084] like Figure 1 As shown in (a) and (d) in the figures, the pesticide formulation of Comparative Example 1 has the smallest particle size because it is a pesticide loaded only by a porous metal framework; as Figure 1 As shown in (b) and (e), the particle size of the pesticide formulation in Example 1 is larger than that in Comparative Example 1. This is because the CNC hydrogel contains a large amount of water and a three-dimensional network structure, and the metal framework MOF is embedded in the gel skeleton, forming multiple physical-chemical encapsulations or network confinement effects, resulting in increased particle size. However, the pesticide formulation in Comparative Example 2 has the largest particle size, combined with... Figure 2 As shown, the –COO- of the nanocellulose in the pesticide formulation of Example 1 and the Zn in the metal framework material 2+ Coordination bonds are formed, thereby promoting the formation of a three-dimensional network structure between the nanocellulose gel and the zinc-based organic framework. The nanocellulose provides support for the growth of the metal framework material, prevents its aggregation, and makes it uniformly dispersed. Therefore, the pesticide formulation of Example 1 has a significantly smaller particle size compared to Comparative Example 2. In addition, it is also beneficial to increase the pesticide loading.

[0085] like Figure 3As shown, the UV spectrophotometer test results indicate that the pesticide formulation CNC Gel-ZnMOFs in Example 1 achieved a pesticide loading rate of 49.68% and an encapsulation efficiency of 99.37%; while the pesticide formulation ZnMOFs in Comparative Example 1 had a pesticide loading rate of 13.45% and an encapsulation efficiency of 58.89%; and the pesticide formulation CNC-ZnMOFs in Comparative Example 2 had a pesticide loading rate of 27.43% and an encapsulation efficiency of 78.35%.

[0086] like Figure 4 As shown, the pesticide formulation prepared by the stepwise synthesis method in Example 1 has a pesticide loading rate of 49.68% and an encapsulation rate of 99.37%, as measured by ultraviolet spectrophotometer. In contrast, the pesticide formulation prepared by the one-step synthesis method in Comparative Example 3 has a pesticide loading rate of 38.24% and an encapsulation rate of 75.32%. Since the zinc porous metal framework ZnMOF is first combined with CNC before loading the pesticide, some pores of ZnMOFs are blocked by CNC or interfaces, reducing the effective loading space. Therefore, loading the pesticide first can ensure that acetamiprid Ace is embedded into the pores of ZnMOFs to the maximum extent, forming a "nanocage encapsulation" structure.

[0087] like Figure 5 As shown in the ultraviolet spectrophotometer test, compared with the commercial acetamiprid pesticide Commercial Ace (mass concentration of 20%, purchased from Shandong Zouping Pesticide Co., Ltd., brand: Saijing) and the acetamiprid technical solution Ace (purchased from Aladdin, CAS: 160430-64-8), the pesticide formulation CNC Gel-ZnMOFs of Example 1 had the highest retention rate after being washed by rain for different periods of time. The retention rate was 78.3% after 1 minute, while the pesticide residue rate of commercial acetamiprid pesticide was only 56.1% after 1 minute of rain washing experiment. This indicates that the pesticide formulation CNC Gel-ZnMOFs of Example 1 has excellent rain washout resistance.

[0088] like Figure 6 As shown in (a) of Example 1, the aphid mortality rate on leaves treated with the pesticide formulation CNC Gel-ZnMOFs was significantly higher than that treated with acetamiprid technical solution Ace and the commercial acetamiprid pesticide Commercial Ace, the latter having relatively limited insecticidal effect. Furthermore, as... Figure 6 As shown in (b) and (c), the pesticide formulation exhibits a clear dose-dependent insecticidal response, with the LC50 of the pesticide formulation CNC Gel-ZanMOFs in Example 1 being [missing data]. 50 The concentration was 11.938 mg / L, which was significantly lower than that of the Commercial Ace treatment group (13.846 mg / L) and the Ace treatment group of acetamiprid technical solution (34.560 mg / L), indicating that the bioavailability of the pesticide formulation in Example 1 was significantly enhanced.

[0089] As shown Figure 7 in the figure, the drug release kinetics of the pesticide formulation of Example 1 in different pH environments (5, 7, and 9) are shown, revealing that the drug delivery system has pH-responsive controlled release behavior; as shown Figure 7 in (a) of the figure, the pesticide formulation of Example 1 showed obvious initial burst release characteristics within the first 24 hours. Among them, the cumulative release rates under the conditions of pH 5.0, 7.0, and 9.0 were 58.9%, 50.6%, and 32.4%, respectively. After 120 hours of release, the cumulative release rates increased to 85.9%, 68.5%, and 44.3%, respectively. The drug release was significantly enhanced in the acidic environment, mainly due to the reduced structural stability of ZnMOFs under low pH conditions, resulting in the degradation of the metal-organic framework and thus promoting the release of Ace. Oxalic acid is released when plant leaves carry out photosynthesis, causing the collapse of ZnMOFs and thus releasing the drug; in order to further clarify the release behavior of CNC-ZnMOFs-Ace, the cumulative release data under different pH conditions were fitted and analyzed using various kinetic models; as shown Figure 7 in (b), (c), and (d) of the figure and the fitting parameters of the release curve with multiple models are shown in Table 1. The fitting correlation coefficients (R 2 ) of all models were greater than 0.92, indicating that the Ritger-Peppas model had an excellent fitting effect on the release process of this system. According to this model, when the release characteristic index n value is less than 0.45, the release behavior conforms to the Fickian diffusion mechanism; while in the range of 0.45 < n < 0.89, the release mechanism shows non-Fickian diffusion characteristics.

[0090] Table 1 Fitting parameters of the release kinetic model of the pesticide formulation of Example 1 at different pH values

[0091]

[0092] Given that there are numerous embodiments of the solution of the present invention, the raw materials and dosages involved can be selected according to actual needs within the limited range. The experimental data of each embodiment are huge and numerous, and it is not suitable to list them one by one here. However, the content to be verified and the final conclusions obtained in each embodiment are close. Therefore, the verification content of each embodiment will not be described one by one here.

[0093] The above description only details the preferred embodiments and principles of the present invention. For those of ordinary skill in the art, based on the idea provided by the present invention, there will be changes in the specific implementation manners, and these changes should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing pesticide formulations supported on a porous metal framework of nanocellulose, characterized in that, Includes the following steps: (1) Polyvinyl alcohol was added to dimethyl sulfoxide and heated to react, resulting in solution A; Zinc nitrate hexahydrate was added to methanol, and the mixture was sonicated and stirred until fully dissolved to obtain solution B. 2-Methylimidazole and the pesticide are dissolved in methanol, and this solution is denoted as solution C. (2) Add cellulose nanocrystals to solution A and heat to react. After the reaction, cool to obtain nanocellulose gel. After thoroughly mixing solutions B and C, the mixture was ultrasonicated, heated to react, and then centrifuged and washed to obtain a porous metal framework material loaded with pesticides. (3) The porous metal framework loading material and nanocellulose gel are mixed and transferred to a high shear mixer for homogenization. Then, the mixture is centrifuged, washed, and cooled to obtain the pesticide formulation.

2. The preparation method according to claim 1, characterized in that, In step (1), the solid-liquid ratio of polyvinyl alcohol to dimethyl sulfoxide is 1g:(5-6)mL, and the reaction time is 10-15min at a temperature of 95-100℃ to obtain solution A.

3. The preparation method according to claim 1, characterized in that, In step (1), the solid-liquid ratio of zinc nitrate hexahydrate to methanol in solution B is 1g:(30-50)mL.

4. The preparation method according to claim 1, characterized in that, In step (1), the solid-liquid ratio of 2-methylimidazole to methanol in solution C is 1g:(20-25)mL, and the solid-liquid ratio of pesticide to methanol is 1g:(40-60)mL.

5. The preparation method according to claim 1 or 4, characterized in that, The pesticides mentioned are acetamiprid, pyrazoline, thiophanate-methyl, or triazophos.

6. The preparation method according to claim 1, characterized in that, In step (2), the solid-liquid ratio of cellulose nanocrystals to solution A is 1g:(10-15)mL, and the reaction time is 30-40min at a temperature of 80-100℃.

7. The preparation method according to claim 1, characterized in that, In step (2), solution B and solution C are thoroughly mixed and then sonicated for 5-10 minutes, followed by a reaction time of 4-10 hours at a temperature of 50-60℃.

8. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of the porous metal framework loading material to the nanocellulose gel is 1:(1-1.5), the homogenization treatment speed is 9000-10000 rpm, and the duration is 5-7 min.

9. The preparation method according to claim 1, characterized in that, In step (3), the centrifugal washing speed is 1000-2000 rpm, and the cold drying time is 24-32 h.

10. A pesticide formulation based on a porous metal framework of nanocellulose prepared by the preparation method according to any one of claims 1-9.

Images