Transparent bordeaux mixture nano-suspension

Abstract

The present application relates to a transparent Bordeaux mixture and a preparation method therefor. The size of basic copper sulfate particles in the suspension is less than 100 nanometers. The basic copper sulfate particles are suspended and dispersed in a water-soluble polymer dispersant, and same is present in water in random coils.

Description

Transparent Bordeaux mixture nanosuspension

Technical field

[0001] The present invention belongs to the field of nano pesticides, and particularly relates to the preparation of a suspension of particles insoluble in water and organic solvents with a size of less than 100 nanometers, especially less than 50 nanometers. [Background Technology]

[0002] Modern agricultural production requires the use of pesticides. Improving the formulation performance of existing pesticides, increasing their efficacy, reducing their dosage, and mitigating their impact on the environment are of great significance to the sustainable development of agriculture.

[0003] An effective way to achieve pesticide reduction is to effectively reduce the particle size of the active ingredients in pesticide formulations. For water-insoluble pesticides, the minimum size is a few nanometers. Nanopesticides refer to formulations in which the pesticide particles are at the nanometer scale (1 to 100 nm). The particle size of traditional pesticide formulations is on the micrometer scale, ranging from a few microns to tens of microns or even larger. If the particle size is reduced to nanometers, the size is reduced by a thousand times. Theoretically, the number of particles can increase by a billion times, and the surface area can increase by a thousand times. The dramatic increase in the number and surface area of ​​pesticide particles allows for more even dispersion on the leaves, more extensive contact with the target, and full and enhanced efficacy.

[0004] On April 1, 2019, the International Union of Pure and Applied Chemistry (IUPAC), celebrating its 100th anniversary, announced its "Top 10 Chemical Inventions That Will Change the World," with nanopesticides topping the list. This is due to the growing global population, projected to approach 10 billion by 2050. Feeding this large population requires a significant increase in agricultural output while minimizing the environmental impact of land use, including reducing pesticide pollution and water consumption. Nanopesticides, with their small particle size and improved target absorption, offer a promising tool for addressing the key challenges of traditional pesticides: environmental pollution, pesticide accumulation in organisms, and the significant increase in pest and disease resistance. While nanopesticides are by no means the only path to sustainable agricultural development, they certainly offer a lower impact on the environment and human health, contributing to a more sustainable future for the planet.

[0005] Bordeaux mixture is a typical inorganic compound pesticide. Over the past century, it has played a significant role in controlling a variety of fungal diseases in plants. It contains no harmful impurities, is less susceptible to pesticide damage, is rain-resistant, and lacks resistance. It can be used in combination with certain other pesticides and remains a widely used broad-spectrum, protective fungicide. The active ingredient in Bordeaux mixture is basic copper sulfate, but its solubility in water is extremely low, at only 1.06 mg / L. Furthermore, one of the common raw materials used in its preparation is calcium hydroxide, which is also poorly water-soluble, resulting in a light blue, viscous suspension. For ease of use, companies prepare basic copper sulfate as a solid and process it into formulations, primarily wettable powders, with a smaller amount of suspension concentrates. The particle size of these formulations ranges from tens to tens of microns. As with other traditional pesticide formulations, the large particle size limits Bordeaux mixture's efficacy and also results in a higher dosage per unit area.

[0006] Bordeaux mixture is an ancient and widely used agricultural fungicide, primarily composed of a mixture of copper sulfate, slaked lime (calcium hydroxide), and water. This mixture is particularly effective in preventing and controlling fungal infections on plants such as grapevines, potatoes, peaches, apples, and bananas. Despite its importance in organic farming, Bordeaux mixture's use has raised some environmental concerns. The long-term, large-scale application of copper-containing preparations is bound to have ecological impacts and harm. In particular, the accumulation of copper, its primary component, can lead to soil and water contamination and potential toxicity to ecosystem organisms such as fish and earthworms.

[0007] High concentrations of copper are used to control fungal and bacterial plant diseases. It is the only product capable of controlling downy mildew caused by the fungus Fischer-Ribes. At lower concentrations, copper is an essential trace nutrient for plants and animals. Most crops require copper as a micronutrient, and the dosage is substantial. For crops grown in acidic organic soils, application concentrations range from 3.4 to 6.7 kg / hectare or 2.0 to 3.4 kg / hectare, respectively. For faster onset of action, foliar sprays at concentrations of 8 g / L of copper ion are also used. The continued and extensive use of copper preparations for plant disease control and as a nutrient inevitably pollutes the environment and affects plant and animal health. Developed countries worldwide are currently working to reduce the use of copper-containing preparations. European Commission Regulation (EC) 889 / 2008 stipulates copper dosages for organic agriculture, recommending a maximum of 1 kg / hectare per treatment, with a maximum of 6 kg / hectare per year. Further work is underway to reduce the maximum permissible copper concentration. A survey conducted in 12 European countries showed that the annual use of copper in organic agriculture was 3,258 tons, which is 52% of the permitted annual dosage. While this has not yet been put on the agenda in my country, the trend suggests that reducing the use of copper preparations is imperative globally.

[0008] There are concerns in Europe about the environmental impacts of the copper content of Bordeaux mixture, particularly the accumulation of copper ions in soil and its long-term environmental impact. Because copper ions can accumulate in organisms, most EU countries have banned the use of Bordeaux mixture. Only a few countries, including Belgium, Cyprus, France, Greece, Hungary, Italy, Malta, Portugal, Romania, and Slovenia, still allow its use.

[0009] Reducing the particle size of copper-containing formulations, thereby improving efficacy and reducing dosage, is undoubtedly an effective approach to addressing the global copper pollution problem. For over a century, Bordeaux mixture, a traditional and widely used pesticide with protective properties, was largely unappreciated, as its particle size impacted control effectiveness and increased dosage. With increasing understanding of pesticide formulations and advancements in innovative technology, the development of clear, transparent Bordeaux mixture at sprayable concentrations (with particle sizes as small as 100nm, and particularly 50nm) has become a pressing issue.

[0010] No data were found on the preparation of nanoscale Bordeaux mixture. Nanotechnology can be used to prepare copper formulations to improve the efficiency of Bordeaux mixture and reduce its environmental impact. The preparation of nanoparticles typically involves reducing copper or its compounds to nanoscale. Such particles may have higher reactivity and better bioavailability due to their increased surface area, potentially improving the environmental friendliness of Bordeaux mixture and enhancing its antifungal efficacy.

[0011] In summary, Bordeaux mixture is an effective agricultural fungicide, but its use is subject to certain restrictions due to environmental considerations. This further necessitates the application of nanotechnology to improve its efficiency and reduce its environmental impact. The present invention explores the feasibility and effectiveness of these methods. Existing technology:

[0012] 1. “Study on the preparation of nano basic copper sulfate fungicide by uniform precipitation method” (Yi Qiushi, Pesticides, 2001, 40(8):20-22)

[0013] The technical solution disclosed in this article cannot produce basic copper sulfate at the strictly nanoscale. The article claims that "nanoparticle basic copper sulfate" is produced by chemically controlling the particle size by reacting copper sulfate with ammonia and heating it. However, no particle size data is provided, and the scale in the electron microscope photograph of the aggregated particles is unrecognizable. It also states that "the prepared nanoparticle basic copper sulfate, when mixed with water containing a small amount of dispersant at a concentration of 1-5‰, is highly dispersed to a nearly translucent state." Based on common sense regarding colloidal solutions, the appearance of the basic copper sulfate dispersion produced by this technology suggests that the particle size should be over several hundred nanometers, or approaching or exceeding micrometers.

[0014] 2. "Preparation and Mechanism of Nano-basic Copper Sulfate Suspension Agent" (Gao Mengmeng, Master's Thesis, Shenyang Agricultural University, 2021)

[0015] The technical solution published in this master's thesis also fails to produce basic copper sulfate at the strict nanoscale. The thesis states that a 40% nano basic copper sulfate suspension was prepared using commercially available "nano basic copper sulfate" powder (particle size not specified) by selecting several additives and grinding process conditions. However, the particle size of the basic copper sulfate in the prepared sample was not given. The size data measured for the ground sample is as follows: 50 The particle size distribution of the copper sulfate prepared by this method is as follows: <5 μm, 98.2% to 91.21%; 5-15 μm, 8.7% to 9.6%; >15 μm, 0.23% to 1.2%. This indicates that the size of the basic copper sulfate prepared by this technology is much larger than 100 nm.

[0016] Given the current technical difficulties in preparing nanoscale particles from solid basic copper sulfate, the present invention requires a novel approach to prepare a transparent Bordeaux mixture nanosuspension smaller than 100 nm, or even smaller than 50 nm. This also demonstrates the significant technical difficulty in preparing the target product of the present invention.

[0017] [Summary of the invention]

[0018] Purpose of the present invention

[0019] One of the objectives of the present invention is to overcome the shortcomings of the prior art and provide an innovative approach and technology that differs from existing Bordeaux mixture preparation techniques—the preparation of transparent Bordeaux mixture. Traditional Bordeaux mixture is the reaction of copper sulfate and quicklime in water. Quicklime is calcium oxide. Slaked lime (calcium hydroxide) is produced in water. Calcium hydroxide reacts with copper sulfate to form basic copper sulfate. Due to the low solubility of calcium hydroxide in water, and the even lower solubility of the product, basic copper sulfate, in water, the resulting Bordeaux mixture is a light blue, viscous suspension with large particle size. The innovative approach and technology of the present invention involves first dissolving copper sulfate, one of the raw materials for preparing Bordeaux mixture, in water to prepare an aqueous solution. One or more selected alkaline compounds are then prepared into an aqueous solution. One or more selected polymer additives are dissolved in the copper sulfate aqueous solution. Under stirring, the addition method and stirring speed are controlled to ultimately obtain a transparent Bordeaux mixture—a nanosuspension.

[0020] Another object of the present invention is to reduce the particle size of the active ingredient (basic copper sulfate) of Bordeaux mixture. For ease of use, commercially, basic copper sulfate solid technical is first prepared in a factory and then processed into a formulation. Since basic copper sulfate is neither water-soluble nor soluble in organic solvents, current technology uses mechanical force to crush and grind it, processing most of it into a wettable powder formulation and a small amount of a suspension formulation. Therefore, the particle size of commercially available Bordeaux mixture ranges from a few microns to tens of microns, which leads to an increase in its dosage. The transparent Bordeaux mixture prepared by the present invention has a particle size of less than 100 nm, especially less than 50 nm, which greatly reduces the particle size during use compared to traditional products.

[0021] Another object of the present invention is to shorten the process flow for obtaining Bordeaux mixture. The present invention integrates the traditional Bordeaux mixture (basic copper sulfate) synthesis process and formulation processing process to directly obtain transparent Bordeaux mixture, reducing the technical synthesis and purification processes, reducing the formulation processing process, simplifying the entire operation process, eliminating the corresponding production equipment, and generating no wastewater during the process, thereby improving production efficiency and being environmentally friendly and energy-saving.

[0022] Another object of the present invention is to provide a highly effective Bordeaux mixture nanosuspension that can be directly used for spraying. Due to its greatly reduced particle size, the nanosuspension significantly improves its efficacy and significantly reduces its dosage, contributing to reducing the input of copper preparations in the ecological environment and reducing pollution.

[0023] The innovative idea of ​​the present invention

[0024] Nanopesticide research targets water-insoluble pesticides. The goal is to disperse them in water at their smallest aggregate size. The typical strategy for preparing these pesticides is to dissolve the active ingredient in a solvent or complex solvent to form a monomolecular dispersion. This solution is then processed through various methods into nanomicelles, nanocrystals, nanospheres, nanocapsules, nanogels, and various nanocarriers. However, for pesticides that are insoluble in both water and organic solvents, current technology alone cannot achieve nanoparticle size, let alone sub-100 nm, through mechanical crushing and grinding.

[0025] The active ingredient of Bordeaux mixture is basic copper sulfate, a typical inorganic compound. It is insoluble in both water and organic solvents. Therefore, preparing it into a transparent suspension dispersion with particle sizes less than 100 nm, particularly less than 50 nm, is a challenge facing nanopesticide research. This requires consideration of a different preparation method than conventional methods. The innovative approach of the present invention is as follows:

[0026] The first step is to prepare water-soluble copper sulfate into an aqueous solution of a certain concentration. In this solution, copper sulfate molecules exist in a monomolecularly dispersed state. On this basis, a suitable water-soluble polymer surfactant (polymer additive) is selected and dissolved in water with it to form a mixed solution of copper sulfate and the water-soluble polymer additive. This serves as component one.

[0027] The second step is to select an alkaline compound that reacts with copper sulfate and dissolve it in water to form a monomolecularly dispersed alkaline solution as group two.

[0028] The third step is to use the pesticide dilution process to reasonably distribute the dilution water used in the spraying operation, and dilute the above-mentioned component one and component two into water in different proportions.

[0029] The fourth step is to add component one to component two, or add component two to component one, controlling different adding methods and speeds, stirring methods and speeds, so that the generated basic copper sulfate particles are at the nanometer scale, thereby obtaining a transparent Bordeaux mixture.

[0030] To achieve this goal, the following points must be focused on:

[0031] (1) Controlling the speed and quantity of basic copper sulfate nuclei formed by the reaction, as well as the rate of crystal growth, is the key to obtaining particles smaller than 100nm, especially smaller than 50nm. This involves selecting the type and amount of the base compound, the type and amount of the water-soluble polymer additive, as well as considering factors such as the change in the system's pH value during the reaction and the stability of the dispersion after the nanoparticles are generated.

[0032] (2) Alkali strength and selection of the alkaline compound. The alkali used in traditional Bordeaux mixture is slaked lime, or calcium hydroxide. Its relatively weak alkalinity results in a slow reaction with copper sulfate, making it easier to control. However, its poor water solubility and large particle size make the even less water-soluble basic copper sulfate difficult to separate, ultimately forming a viscous suspension with large particles. In addition to calcium hydroxide, other alkaline compounds can include sodium hydroxide, potassium hydroxide, and ammonium hydroxide. The first two are strong bases and react quickly with copper sulfate. Ammonium hydroxide, however, has a relatively weak alkalinity and reacts slower with copper sulfate than the first two, resulting in a slower formation of basic copper sulfate. To control the formation rate of basic copper sulfate, as well as the nucleation, crystallization, and growth rates of the particles, ammonium hydroxide is the preferred reactant. If the reaction rate is desired to be increased, combining ammonium hydroxide with one of the above two reactants can be considered. By selecting an appropriate mixing ratio, the reaction process can be regulated.

[0033] (3) Selection of the type and amount of water-soluble polymer additive. Copper sulfate reacts with an alkali compound to form basic copper sulfate. Since the product is insoluble in water, molecules will inevitably aggregate in water, forming crystal nuclei. These nuclei continuously combine with the generated basic copper sulfate molecules, causing the crystals to grow continuously and eventually precipitate out of the water. The objective of the present invention is to control the crystal size of the generated basic copper sulfate to be no larger than 100 nm, particularly no larger than 50 nm. To block the crystal nuclei generated in water, disperse, stabilize, and suspend them, and prevent and control further crystal growth, a water-soluble polymer additive must be added to the system. Water-soluble polymer additives have hydrophilic groups, allowing them to dissolve in water to form colloidal solutions. The viscosity of colloidal solutions is much greater than that of small molecule surfactants at the same concentration. The high viscosity of water-soluble polymer solutions is due to the different morphological structures of water-soluble polymers in water compared to small molecules. Due to their large molecular weight and long molecular chains, polymers do not dissolve in water as straight chains, but rather as random coils. This random coil is dispersed in water in a molecularly dissolved state, with sizes ranging from a few nanometers to tens of nanometers, or even hundreds of nanometers, depending primarily on its relative molecular mass and the flexibility of its molecular chain. This random coil suspends the nanocrystals generated in solution. This is due to the loose spatial structure of the random coil. Under stirring, the small basic copper sulfate crystals generated by the reaction enter this structure, thereby dispersing, stabilizing, suspending, and preventing crystal aggregation, thereby preventing and controlling further growth. Water-soluble polymers are classified by type into anionic, cationic, zwitterionic, and nonionic types; and by source into natural polymers and their derivatives, as well as synthetic polymers. The selection and use of water-soluble polymer additives, as well as their dosage, are determined through experimentation.

[0034] (4) Selecting the dilution water volume. The amount of dilution water actually determines the concentration of copper sulfate nanoparticles generated in the system. Theoretically, the lower the dilution water used, the higher the concentration of copper sulfate nanoparticles, the greater the tendency for crystals to grow and aggregate due to mutual collisions, the more unstable the system, and the greater the risk of precipitation. Conversely, a larger dilution water volume, as long as the amount of polymer additive is sufficient, will more easily form a transparent and stable Bordeaux mixture suspension.

[0035] Explanation of terms

[0036] Dispersed system: A dispersed system is formed when one or more substances are dispersed in another. The dispersed substance in a dispersed system is called the dispersed phase, and the other substance is called the dispersion medium. Based on the size of the dispersed phase particles, dispersed systems are categorized as: molecular (ionic) dispersed systems (particle size < 1 nm) and colloidal dispersed systems (particle size < 100 nm).

[0037] Colloids and Sols: A colloid is a state in which matter exists at a certain degree of dispersion, rather than being an inherent state of a particular type of substance. Many normally insoluble substances can, under appropriate conditions, disperse in a medium to form a seemingly uniform solution. While superficially indistinguishable from a true solution, their diffusion rate and permeability, among other factors, place them within the realm of colloidal substances and are referred to as sols.

[0038] Classification of Colloidal Solutions: Based on their stability and the structure of their colloidal particles, they are divided into the following categories: 1. Lyophobic sols, formed by insoluble substances dispersed in a dispersion medium, are referred to as sols. These particles consist of varying numbers of molecules, exhibiting large interphases and apparent free energies. These sols are highly unstable and easily disrupted, leading to aggregation and irreversible return to their original state. 2. Solutions of polymer compounds, whose molecular size reaches the colloid range and exhibits colloidal properties, are true molecular solutions, thermodynamically stable, and reversible systems. These sols are also known as lyophilic sols.

[0039] An emulsion is a dispersed system consisting of two liquids. It consists of one liquid dispersed in the form of tiny droplets throughout another immiscible liquid. Typically, one liquid is water or an aqueous solution, while the other is an organic solvent immiscible with water, generally referred to as an "oil." For a given "oil" and water, an emulsion can form either an oil-in-water emulsion (O / W), where the oil is dispersed in water, or a water-in-oil emulsion (W / O), where the water is dispersed in the oil.

[0040] Relationship between emulsion appearance and droplet size: Emulsions have internal phase droplets of varying sizes, which differ in their light absorption, reflection, and other properties, resulting in distinct appearances, as shown in the table below. Therefore, the distribution of internal phase droplet sizes can be roughly determined based on the emulsion's appearance. Emulsions with droplets <0.1 μm are called nanoemulsions or microemulsions.

[0041] System: The so-called system refers to the system in which an alkaline solution is added to an aqueous copper sulfate solution and reacted with the copper sulfate solution while controlling the addition method, speed, and stirring speed during the preparation of a transparent Bordeaux mixture nano-basic copper sulfate suspension dispersion. The system is composed of copper sulfate, an alkaline compound, a polymer additive, and water.

[0042] Component: A component is a composition comprising one or more ingredients. In principle, any ingredient used in this invention can constitute a component on its own. However, for ease of packaging, transportation, and use, the components should be simplified. The principles are: 1) the ingredients should not react with each other; 2) the number of components formed by the ingredients should not be too large.

[0043] Ingredients: The so-called ingredients refer to the raw materials used in the present invention, including water-soluble copper sulfate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, water-soluble polymer additives and water.

[0044] Polymer additives are water-soluble macromolecular compounds containing hydrophilic groups or hydrophobic backbones. They are also called polymer surfactants or polymer additives. Polymer additives can provide dispersion, suspension, emulsification, and stabilization. Based on the nature of the groups, they can be categorized as nonionic, anionic, cationic, and zwitterionic.

[0045] Particle size: also known as particle size, refers to the size of the basic copper sulfate particles generated in the system. These particles are usually crystalline grains and do not specifically refer to the microscopic morphological structure of the grains.

[0046] Sub-100 nanometers: This is a statistical classification of pesticide particle sizes within a system. All particle sizes within the system exhibit a statistical distribution. The sub-100 nanometer dispersion described herein means that at least 80% of the particles are smaller than this size. Particles larger than 100 nanometers constitute only a small fraction.

[0047] Ionic strength: Ionic strength (I) is a measure of the effect of all ions in a solution on the electric field. It is related to the concentration and charge of the ions. The formula for calculating ionic strength is as follows: i is the concentration of the i-th ion (in moles per liter), z i is its charge number.

[0048] Low ionic strength of water: The ionic strength of water is very low. This is due to the low dissociation rate of pure water. For pure water, the hydrogen ions (H + ) and hydroxide ion (OH-) concentrations are very low (approximately 10 -7 M). The dissociation rate of water is affected by many factors, including temperature, pressure, and the nature of the solvent. When the pH value is 7, the dissociation rate of water is 1.8×10 -7 % refers to the dissociation of water molecules into hydrogen ions (H + ) and hydroxide ions (OH - ) ratio.

[0049] Charge screening effect: The charge screening effect refers to the fact that ions in a solution influence the distribution of surrounding ions through their charge, thereby reducing the interaction between ions. Under conditions of high ionic strength, the ions in the solution tend to be more evenly distributed, reducing the influence of the charge in the solution, which may lead to a weakening of the electrostatic repulsion between nanoparticles and increase the possibility of particle aggregation. The key technologies of this invention lie in the following aspects:

[0050] 1. Comparison of the reaction of copper sulfate and alkali (sodium hydroxide, potassium hydroxide, ammonium hydroxide) to form basic copper sulfate

[0051] Copper sulfate (CuSO4) reacts with sodium hydroxide (NaOH), potassium hydroxide (KOH), or ammonium hydroxide (NH4OH) to produce basic copper sulfate. The following two reactions are compared based on ease of implementation, mild reaction conditions, and yield:

[0052] ⑴Reaction with NaOH or KOH:

[0053] The reaction between CuSO4 and NaOH or KOH is the same. They can produce either copper hydroxide or basic copper sulfate, depending on the molar ratio of the reactants. Taking potassium hydroxide as an example, the reaction formulas are as follows:

[0054] CuSO4+2KOH→Cu(OH)2↓+K2SO4

[0055] 2CuSO4+2KOH→Cu2(OH)2SO4↓+K2SO4

[0056] The key difference between producing copper hydroxide and basic copper sulfate lies in the amount of base used. Two base molecules react with one copper sulfate molecule to produce a precipitated copper hydroxide (Cu(OH)2). To form basic copper sulfate, the amount of base must be controlled—reduced to prevent complete neutralization of all copper ions in the copper sulfate, allowing some to precipitate as basic copper sulfate. The ideal amount of base depends on the desired chemical formula for basic copper sulfate, specifically the ratio of copper sulfate to hydroxide.

[0057] Ease of implementation and reaction conditions

[0058] ① Feasibility: It is relatively easy to react CuSO4 with NaOH or KOH to form basic copper sulfate, because NaOH and KOH have high solubility in water and can quickly react with copper sulfate to form copper hydroxide precipitate. The formation of basic copper sulfate can be promoted by adjusting conditions (such as solution concentration and pH value).

[0059] ② Reaction conditions: These reactions usually proceed at room temperature and do not require special temperature control, which are mild reaction conditions.

[0060] ③ Yield: The yield is relatively high because the formation of the product can be optimized by precisely controlling the amount of reactants and reaction time.

[0061] ⑵Reaction with NH4OH:

[0062] CuSO4 reacts with NH4OH to generate basic copper sulfate according to a reaction formula similar to that of potassium hydroxide. For example:

[0063] 2CuSO4+2NH4OH→Cu2(OH)2SO4↓+(NH4)2SO4

[0064] The exact chemical composition of basic copper sulfate may vary depending on the reaction conditions and the ratio of the reactants. For example, another reaction form is:

[0065] 3CuSO4+6NH4OH→Cu3(OH)4(SO4)2↓+2(NH4)2SO4+2H2O

[0066] This reaction represents the reaction of three copper sulfate molecules with six ammonium hydroxide molecules to produce one basic copper sulfate molecule, two ammonium sulfate molecules, and water. This reaction equation is based on a specific form of basic copper sulfate; the actual product composition may vary depending on experimental conditions (e.g., reactant concentrations, solution pH, temperature, etc.).

[0067] Ease of implementation and reaction conditions

[0068] ① Feasibility: Although basic copper sulfate can also be produced by reacting NH4OH with CuSO4, this process may be more complicated than the NaOH or KOH solution because ammonia (NH4OH) is a weak base in water and its ability to produce copper hydroxide is relatively weak, requiring a longer time or more ammonium hydroxide to complete the reaction.

[0069] ② Reaction conditions: The reaction conditions of NH4OH are mild, but due to its weaker alkalinity, a higher concentration or more reaction time may be required to achieve the same reaction progress.

[0070] ③ Yield: The yield may be limited by the reaction conditions (such as the concentration of ammonium hydroxide, the pH value of the solution, etc.), and optimizing the yield may be more challenging compared to NaOH or KOH.

[0071] ⑶Comparison of the two reactions

[0072] (1) Chemical Properties: NaOH and KOH are strong bases that react quickly and efficiently with CuSO4; whereas NH4OH is a weak base with a relatively slow reaction rate. While the former is undoubtedly advantageous for reactions aimed at obtaining solid precipitation of basic copper sulfate, a slower and gentler reaction is undoubtedly beneficial for controlling particle size when aiming to obtain nanoscale basic copper sulfate suspensions.

[0073] ⑵ Reaction rate and yield: The rate and yield of the reaction of NaOH and KOH are usually higher than those of the reaction of NH4OH because the strong base can more effectively promote the formation of precipitates in a shorter time.

[0074] ⑶ Ease of operation: The use of NaOH and KOH is usually easier to achieve and obtain solid products due to their fast reaction speed and simple operation, so they are often used in laboratory-scale preparations.

[0075] In summary, NaOH or KOH solutions are generally preferred for preparing basic copper sulfate solid products in the laboratory because these solutions have advantages in reaction speed, ease of operation, and yield. However, considering that the purpose of the present invention is to prepare basic copper sulfate nano-suspension dispersion, the NH4OH solution with a slower reaction rate and slower precipitation formation should be more suitable.

[0076] In some cases, to further slow the formation rate of basic copper sulfate crystals and prevent rapid growth and aggregation, it is possible to add a pH-regulating agent to the system to lower the pH of the local area formed when the base (such as ammonia) is added to the system. For example, ammonium chloride, a salt of a strong acid and a weak base, can be added to form a buffer with ammonia.

[0077] 2. Selection of solutions for preparing nano basic copper sulfate

[0078] The present invention aims to prepare a transparent basic copper sulfate nano-dispersion, rather than hoping to quickly obtain a high-yield basic copper sulfate solid precipitate. Therefore, when selecting the most suitable solution, the reaction conditions, the controllability of the reactants, and the dispersibility and stability of the final product should be considered. Although copper sulfate can react with sodium hydroxide (NaOH), potassium hydroxide (KOH), or ammonium hydroxide (NH4OH) to form basic copper sulfate, different methods may have different advantages in preparing stable nanoparticle dispersions.

[0079] (1) Using NaOH or KOH: These strong bases react quickly with CuSO4, which helps to quickly form a precipitate. Although careful control of the addition rate, concentration, and mixing of the reactants can promote the formation of nanoparticles, it is not conducive to the formation and stability of a transparent basic copper sulfate nanodispersion.

[0080] (2) Using NH4OH: NH4OH has a slower reaction rate, but this method may make it easier to control the growth rate of grains and the formation of precipitation, which is conducive to the formation of nanoparticles with more uniform size. In addition, ammonia (NH4OH) itself is an aqueous solution and does not need to be dissolved, but its concentration can be reduced by dilution or by adding buffer substances to stabilize the pH value. This can help stabilize nanoparticles under certain conditions and prevent excessive grain growth.

[0081] Thinking about solution selection

[0082] In the preparation of nanoscale basic copper sulfate, the use of NH₄OH may provide greater flexibility in controlling particle size distribution, and a slower reaction rate is more conducive to the formation and stability of nanocrystals. Furthermore, the optimal approach should consider nanoparticle stabilization techniques, such as selecting appropriate dispersants and surfactants, which are also important for preventing particle aggregation.

[0083] Based on the difficulty of obtaining basic copper sulfate and the purpose of preparing a transparent Bordeaux mixture with a particle size of less than 100 nm, especially less than 50 nm, the present invention selects a reaction scheme of copper sulfate with sodium hydroxide, potassium hydroxide, and ammonium hydroxide through evaluation and comparison of the above schemes, and preferably selects a reaction scheme of copper sulfate with ammonium hydroxide.

[0084] Traditional commercial production of basic copper sulfate is to obtain high-purity solid technical materials for further processing into formulations. The transparent Bordeaux mixture prepared in this invention is a suspension dispersion that requires no purification and can be used directly for spraying. The so-called "by-products" in the system, such as (NH4)2SO4 and K2SO4, can be used as nitrogen and potassium fertilizers for crop growth, thus maximizing resource utilization.

[0085] 3. Control of reaction conditions for preparing nano basic copper sulfate

[0086] Nanosized basic copper sulfate is prepared by reacting a copper sulfate solution with an alkaline solution (NaOH, KOH, NH4OH) during mixing. The key lies in controlling the reaction conditions, such as reactant concentration, reaction temperature, stirring speed, and the method of adding the alkaline solution. The reaction conditions that need to be considered in the preparation of nanosized basic copper sulfate are:

[0087] (1) Prepare the solution. For the copper sulfate solution, first prepare a copper sulfate solution of a certain concentration. The concentration should not be too high, as this will cause a vigorous reaction and make it difficult to control the particle size. For the alkaline solution, select and prepare a solution of NaOH, KOH, or NH₄OH. The concentration of the alkaline solution should also be moderate; a high concentration may result in large product particles.

[0088] ⑵ Control the reaction conditions. Slowly add the alkaline solution to the copper sulfate solution under stirring. Control of the drop rate is crucial for the uniformity of particle size and distribution. Stirring: Ensure continuous and uniform stirring throughout the reaction to promote uniform reaction and avoid local oversaturation leading to particle aggregation. Temperature control: The reaction can be carried out at room temperature, or the temperature can be appropriately controlled (for example, lowered) to optimize the formation and growth of nanoparticles.

[0089] (3) Nanoparticle growth and stabilization. Polymer surfactants, added before or during the reaction to disperse and suspend the particles, help reduce particle size and prevent aggregation. pH adjustment: By fine-tuning the solution pH (e.g., by adding buffers), the precipitation process and product morphology of basic copper sulfate can be further controlled.

[0090] 4. Control method for generating transparent nanometer basic copper sulfate dispersion by reaction of copper sulfate solution with alkaline solution

[0091] Copper sulfate solution and alkaline solution (NaOH, KOH or NH4OH) generate nano-sized basic copper sulfate. To obtain a stable and transparent nano-dispersion, the reaction conditions need to be controlled to promote the stable dispersion of nanoparticles in the solution and prevent the formation of macroscopic crystal precipitation. In addition, to maintain the transparency of the solution, the size of the nanoparticles needs to be very small, at least less than 100nm, and highly dispersed. The following are possible control methods:

[0092] (1) Control nanoparticle size. Ultrasonic treatment, if possible, can help break up aggregated particles and promote the formation of smaller nanoparticles. Control the reaction conditions. By fine-tuning the addition rate of the alkaline solution, the stirring speed of the solution, and the reaction temperature, the nucleation and growth process of basic copper sulfate nanoparticles can be controlled, thereby obtaining smaller particle size.

[0093] (2) Use a suitable dispersant or surfactant. Adding a suitable dispersant or surfactant can form a stable adsorption layer on the surface of the nanoparticles, preventing aggregation between particles and helping to maintain a stable suspension of the nanoparticles in the solution. It is crucial to select a dispersant that is compatible with basic copper sulfate.

[0094] (3) pH and ionic strength control. Adjust the pH of the solution in the reaction area to a range that is conducive to stable dispersion of the nanoparticles. Ionic strength adjustment: Adjust the ionic strength of the solution to reduce charge shielding effects that may cause particle aggregation.

[0095] (4) Dilution effect. After obtaining the initial nano-basic copper sulfate solution, appropriate dilution can reduce the interaction between particles and help maintain the transparency of the solution. This shows that determining the amount of water used for dilution is important.

[0096] It is important to note that achieving these goals requires precise experimental design and optimized conditions. Transparent nanosolutions often require very small and highly uniformly dispersed particles. Furthermore, even when nanoparticle dispersion is achieved, the color of the solution may be affected by the specific size and morphology of the nanoparticles, especially when the solution contains high concentrations of nanoparticles. Therefore, it is necessary to repeatedly adjust the type and concentration of the polymer dispersant, the pH value of the reaction, and other conditions.

[0097] 5. Selection of polymer additives (polymer dispersants) compatible with basic copper sulfate

[0098] When preparing nano-sized basic copper sulfate dispersions, it is crucial to prevent precipitation and maintain transparency by selecting appropriate water-soluble polymer additives as dispersants. These substances can help stabilize the nanoparticles, preventing them from aggregating and precipitating, thereby maintaining the transparency of the solution. The water-soluble polymer additives selected in the present invention include:

[0099] (1) Polyvinylpyrrolidone (PVP) is a commonly used polymer dispersant that can effectively stabilize various nanoparticles and prevent them from aggregating. PVP can form a stable protective layer on the surface of nanoparticles by adsorption.

[0100] (2) Polyvinyl alcohol (PVA) is another commonly used polymer dispersant, particularly suitable for aqueous systems. It can form a protective layer on the surface of nanoparticles to prevent aggregation between particles.

[0101] (3) Sodium dodecyl sulfate (SDS) and its derivatives, dodecyl ether sulfate (sodium salt and ammonium salt), are anionic surfactants widely used to stabilize nanoparticles. The dodecyl lipophilic group in the molecule can adsorb on the surface of nanoparticles, while the hydrophilic group extends into the solution, enhancing the dispersion of the particles in water.

[0102] (4) Sodium carboxymethyl cellulose (CMC), a water-soluble polymer, can be used as an effective dispersant to stabilize various nanomaterials. It forms a stable layer on the surface of nanoparticles by adsorption, improving dispersibility.

[0103] (5) Polyoxyethylene ether and its derivatives are a type of nonionic surfactant. Polyoxyethylene ether is a hydrophilic group, while the lipophilic group can be an alkyl fatty chain, an alkyl aromatic group, an oil group, etc. It can form micelles with a hydrophilic group on the outside and a lipophilic group on the inside, allowing nanoparticles to be dispersed in them.

[0104] (6) Amino silicone oil: Amino-modified silicone oil is a nonionic surfactant that can be used to disperse nanoparticles in organic solvents. Amino silicone oil is a good choice for applications that require dispersing nanoparticles in non-aqueous media.

[0105] ⑺Other anionic and nonionic polymer surfactants.

[0106] It should be noted that SDS (sodium dodecyl sulfate) and its derivatives dodecyl ether sulfate (sodium salt or ammonium salt), as well as CMC (sodium carboxymethyl cellulose) are all anionic surfactants, which means that their molecules contain parts that can dissociate into negative charges in water. +2 ), they may form certain complexes with copper ions. However, whether the products of these reactions are soluble in water depends on the specific conditions and reaction ratio. Although the reaction may form a precipitate, especially when the concentration of copper ions in the solution is high. But if the concentration of SDS is high enough to provide sufficient water solubility through its hydrophilic groups, this complex may maintain a certain water solubility under certain conditions. The same is true for the reaction of CMC with copper ions. Since CMC is a polymer dispersant, its interaction with copper ions may cause copper ions to form complexes on the CMC chains. In this case, the water solubility of the complex mainly depends on the molecular weight of CMC, the degree of substitution and other conditions in the solution. In some cases, CMC can act as a stabilizer to help copper ions remain dispersed in aqueous solution.

[0107] In summary, when using these polymeric additives as dispersants, it is important to determine the most appropriate concentration and conditions through experimentation to achieve optimal dispersion and solution clarity. Furthermore, the selection of a dispersant should also consider the properties required by the end-use application, such as biodegradability and its impact on the ecological environment. Therefore, naturally biodegradable polymeric additives or their derivatives are preferred. Furthermore, in some cases, a combination of different dispersants, known as composite additives, may be necessary to achieve optimal results.

[0108] 6. The appropriate pH range is conducive to the stable dispersion of nanoparticles

[0109] The stable dispersion state of nanoparticles in aqueous solution is affected by many factors, including the pH value of the solution. The appropriate pH range depends on the specific nanoparticle type, surface properties, and the characteristics of the dispersant or surfactant used. Generally speaking, in order to enhance the stability of nanoparticles, the pH value should be adjusted to a range that can maximize the surface charge of the nanoparticles, which helps to prevent the aggregation of nanoparticles through electrostatic repulsion.

[0110] Different types of nanoparticles have different pH ranges. For example, metal oxide nanoparticles (such as TiO2 and ZnO) typically have an isoelectric point (IEP) (the pH value at which the particle surface charge is zero). Specifically, for many common metal oxide nanoparticles, the stability of the nanoparticles is better when the pH is far from their isoelectric point (IEP). For example, the IEP of TiO2 is approximately pH 6.5, so nanoparticles are generally more stable in environments with a pH < 5 or pH > 8. Silver nanoparticles (Ag): Silver nanoparticles generally exhibit good stability in slightly acidic to neutral environments (approximately pH 5.5 to 7) because within this pH range, the surface may have sufficient negative charge to promote electrostatic repulsion between particles. Organic nanoparticles (such as polymer nanoparticles): The stable pH range of these nanoparticles depends on the properties of the polymer. Generally speaking, good stability can be achieved by keeping the solution pH within the range where the polymer does not degrade and the surface charge of the nanoparticles can be maintained.

[0111] For basic copper sulfate nanoparticles, the ideal pH range may be from weakly acidic to weakly alkaline (approximately pH 6 to 7.5). Within this range, the nanoparticles are stable.

[0112] It is worth noting that the appropriate pH range should also be determined experimentally, as the stability of nanoparticles is not only affected by pH but may also be affected by the complex interactions of ionic strength, temperature, and the presence of specific dispersants or surfactants in the solution. Conducting a series of dispersibility tests to observe the stability and dispersibility of nanoparticles at different pH values ​​can help determine the optimal pH range.

[0113] 7. Effect of ionic strength on charge screening effects leading to particle aggregation

[0114] Adjusting the ionic strength of a solution is a method for controlling the concentration of electrolytes in a solution, aiming to influence the interactions between charged particles in the solution. Ionic strength has a significant impact on the charge screening effect in solutions. This effect occurs when ions in a solution influence the distribution of surrounding ions through their charge, thereby reducing interactions between ions. Under conditions of high ionic strength, ions in the solution tend to be more evenly distributed, reducing the influence of the solution's charge. This can weaken the electrostatic repulsion between nanoparticles and increase the likelihood of particle aggregation.

[0115] ⑴ Adjusting the ionic strength in the solution is usually achieved by adding non-reactive salts. These salts dissociate in the solution, releasing a large number of ions, which affects the overall ionic strength. The operation method is as follows: ⑴ Increase ionic strength. Adding an appropriate amount of inert electrolyte (such as sodium chloride NaCl, potassium nitrate KNO3, etc.) to the solution can increase the ionic strength of the solution. This practice is often used to reduce the electrostatic repulsion between charged nanoparticles and help the particles approach each other. ⑵ Reduce ionic strength. Reducing the electrolyte concentration in the solution or using a solvent with low ionic strength can reduce the ionic strength. This is usually achieved by diluting the solution or changing the solvent, which helps to enhance the electrostatic interaction between charged particles, thereby preventing excessive aggregation of particles.

[0116] In practical applications, the proper adjustment of ionic strength requires a comprehensive consideration of the properties of the nanoparticles, the desired dispersion stability, and the ultimate application purpose. For example, while excessively high ionic strength can help overcome electrostatic repulsion, it may also promote nonspecific attractive forces such as van der Waals forces, leading to nanoparticle aggregation.

[0117] (2) The solvent used in the present invention is water. The ionic strength of water refers to half of the sum of the product of the concentration of all ions in the solution and the square of their charge. For pure water, the ionic strength is very low because the hydrogen ions (H + ) and hydroxide ions (OH - ) is very low (approximately 10 -7 M). However, in actual applications, water often contains various dissolved salts and minerals, which will increase the ionic strength of water.

[0118] Methods to reduce the ionic strength of water include: ① Deionization. Using deionized water or distilled water can significantly reduce the ionic strength of water. Deionized water is obtained by removing most of the ions in water through ion exchange, reverse osmosis or other water treatment technologies. ② Ultrapure water: Using an ultrapure water system (such as a system that combines reverse osmosis and ion exchange) can produce water with extremely low ionic strength. Ultrapure water is widely used in laboratories and high-tech industries, and its ionic strength can be close to zero. ③ Ion exchange: Specific ions in water can be selectively removed through ion exchange resins, further reducing the ionic strength. This method can specifically remove cations or anions that cause the ionic strength to increase. The choice of method to reduce the ionic strength of water often depends on application requirements, cost considerations, and the required water quality standards.

[0119] When preparing nanosized basic copper sulfate solutions, water with a low ionic strength is required. Low ionic strength reduces the charge shielding effect in the solution, thereby enhancing the electrostatic repulsion on the surface of the basic copper sulfate nanoparticles. This repulsive force prevents aggregation of the nanoparticles and maintains their stable dispersion in the solution.

[0120] Water with low ionic strength has the following advantages: ① Enhanced electrostatic repulsion: In a low ionic strength environment, the surface charges of nanoparticles are less shielded, resulting in stronger electrostatic repulsion between particles, which helps prevent particle aggregation. ② Improved stability: Low ionic strength helps maintain the dispersion stability of nanoparticles in solution, reducing the risk of precipitation and thus maintaining the clarity and transparency of the solution. ③ Controlled nucleation and growth: During the synthesis of nanoparticles, low ionic strength facilitates precise control of the nucleation and particle growth processes, helping to obtain nanoparticles with a narrow size distribution.

[0121] The main purpose of reducing the ionic strength of high-hardness water (i.e. water with high calcium and magnesium ion content) is to remove or reduce the polyvalent metal ions such as calcium and magnesium. This not only reduces the hardness of the water, but also helps to reduce the total ionic strength of the water. The treatment methods implemented are: ① Ion exchange softening water, using ion exchange resin to absorb calcium (Ca 2+ ) and magnesium (Mg 2+ ) ions. ② Reverse osmosis (RO) systems use a semipermeable membrane under pressure to remove dissolved solids, including hardness ions such as calcium and magnesium, from the water. ③ Chemical precipitation: Adding chemical precipitants (such as sodium carbonate) to the water causes the calcium and magnesium ions in the water to form insoluble precipitates, which are then removed by filtration. ④ Water stabilizers: Adding water stabilizers that form stable complexes with calcium and magnesium ions reduces the activity of these ions.

[0122] Water stabilizers mainly include: polycarboxylates, such as polyacrylic acid (PAA), sodium polyacrylate (PAAS), and polymaleic anhydride copolymers; phosphates and their derivatives, such as sodium hexametaphosphate (STPP) and sodium pyrophosphate; chelating agents, such as ethylenediaminetetraacetic acid (EDTA), oxalic acid, citric acid, and carboxymethyl chitosan; and natural organic acids, such as citric acid and tartaric acid.

[0123] 8. The amount of dilution water is another key factor in obtaining nano basic copper sulfate

[0124] To make the transparent dispersion of nano basic copper sulfate obtain stable, in addition to the influence of the above factors, the dilution water consumption is also a key factor that needs to be controlled. High concentrations of basic copper sulfate are not conducive to the stable dispersion of nanoparticles. The mutual collision between particles can cause the merging and growth of particles, and eventually precipitation occurs. Therefore, for the basic copper sulfate nanoparticle dispersion with a certain concentration prepared under certain conditions, it is hoped that there should be a certain relationship between the time range and the dilution water consumption that keep the solution transparency stable. This relationship needs to be confirmed by experiment.

[0125] The relationship between the basic copper sulfate obtained in the present invention and the amount of dilution water is as follows: to obtain a transparent nano-suspension containing 20 g of the active ingredient of basic copper sulfate, the amount of dilution water per mu is generally not less than 2 kg, that is, the concentration of the transparent basic copper sulfate suspension should generally be less than 1%.

[0126] Characteristics of transparent Bordeaux mixture nanosuspension

[0127] The transparent Bordeaux mixture nano-suspension is a nano-suspension in which basic copper sulfate particles are suspended and dispersed in a high molecular dispersant with a random coil morphology.

[0128] The size of the basic copper sulfate particles is below 100 nanometers.

[0129] The polymer dispersant in the form of random coils is compatible with basic copper sulfate.

[0130] The polymer dispersant in the form of a random coil structure is at least one of the following:

[0131] Polyvinylpyrrolidone;

[0132] Polyvinyl alcohol;

[0133] Sodium lauryl sulfate and its derivatives;

[0134] Sodium carboxymethyl cellulose;

[0135] Polyoxyethylene ether and its derivatives;

[0136] Amino silicone oil.

[0137] The transparent Bordeaux liquid nanosuspension uses pure water as a solvent.

[0138] The pH range of the transparent Bordeaux mixture nanosuspension is from weak acid to weak alkaline.

[0139] The pH value range of the transparent Bordeaux mixture nanosuspension is 5.5-8.

[0140] The preferred pH range is 6 to 7.5.

[0141] Preparation method of transparent Bordeaux mixture (nano basic copper sulfate)

[0142] The present invention adopts the following technical solutions:

[0143] A method for preparing a transparent Bordeaux mixture nanosuspension comprises the following steps:

[0144] 1) adding an aqueous copper sulfate solution to an aqueous polymer dispersant solution, stirring and dispersing the solution to form a transparent solution, thereby obtaining a mixed solution of copper sulfate and the polymer additive, referred to as component A; the polymer dispersant exists in the aqueous solution in the form of a random coil structure;

[0145] 2) Selecting an alkaline compound that reacts with copper sulfate and dissolving it in water to form a monomolecularly dispersed alkaline solution, referred to as component B;

[0146] 3) While stirring, add component B to component A, controlling the addition speed and stirring speed to uniformly disperse the components to obtain a transparent Bordeaux mixture nanosuspension.

[0147] In order to obtain a better stabilization effect, the pH value of the product transparent Bordeaux mixture nanosuspension was checked and adjusted to be weakly acidic to alkaline.

[0148] The pH range is 6 to 7.5.

[0149] 1. Prepare a mixed aqueous solution of water-soluble polymer additives and copper sulfate

[0150] According to the distribution ratio of dilution water, the selected water-soluble polymer additive (or composite additive) aqueous solution and copper sulfate aqueous solution are prepared respectively. The water-soluble polymer additive and copper sulfate are added to the water in their respective distribution ratios, stirred and dissolved, to obtain the water-soluble polymer additive aqueous solution and copper sulfate aqueous solution.

[0151] The two solutions are mixed in a certain mixing manner. For example, a copper sulfate aqueous solution is added to an aqueous solution of a water-soluble polymer additive, or an aqueous solution of a water-soluble polymer additive is added to an aqueous copper sulfate solution, and stirred to obtain a transparent and uniform mixed aqueous solution, referred to as component A.

[0152] 2. Prepare alkaline aqueous solution

[0153] Add the selected alkali compound to the assigned dilution ratio of water and stir to obtain an aqueous alkali solution, referred to as component B. During this process, it should be noted that the dissolution of the alkali in water is an exothermic process. To avoid concentrated exothermicity, the alkali compound should be added in small, multiple additions.

[0154] 3. Reaction of alkaline aqueous solution and copper sulfate mixed aqueous solution

[0155] Under appropriate stirring speed, add the alkaline aqueous solution to the mixed aqueous solution of copper sulfate and polymer additive according to a certain addition method and speed. Observe that the reaction system remains transparent until the alkaline aqueous solution is added.

[0156] Continue stirring and adjust the pH of the system to 6-7.5. The system will appear as a transparent sky-blue solution, i.e., a transparent Bordeaux mixture nanodispersion. Observe the time when the transparent dispersion begins to precipitate. This period is the spraying operation period.

[0157] [Implementation Method]

[0158] Example 1.

[0159] Bordeaux mixture nano-suspension dispersion can be used to prevent and control downy mildew and bacterial angular leaf spot of cucumber. The dosage of active ingredient is 60 grams per mu, and the dilution water dosage is 15 kilograms.

[0160] According to the following molecular ratio of chemical reaction formula:

[0161] 3CuSO4+6NH4OH→Cu3(OH)4(SO4)2↓+2(NH4)2SO4+2H2O

[0162] The dosage of each component, the distribution ratio of dilution water, and the preparation method of the solution are listed in the following table:

[0163] How to do it:

[0164] ⑴ In a suitable container, dissolve anhydrous copper sulfate in 3 kg of water (accounting for 20% of the dilution water volume), stir to dissolve it, and obtain a transparent copper sulfate aqueous solution.

[0165] (2) In another appropriate container, add Tween 80, alkylaryl polyoxypropylene polyoxyethylene ether, and AES to 10 kg of water (accounting for 67% of the dilution water volume) and gently stir to dissolve to obtain an aqueous solution of the polymer additive.

[0166] ⑶ Under stirring, add the copper sulfate aqueous solution to the aqueous solution containing the polymer additive, stir and disperse to form a transparent solution, and obtain a mixed solution of copper sulfate and polymer additive, which is called component A.

[0167] (4) In another appropriate container, add aqueous ammonia to 2 kg of water (accounting for 13% of the dilution water volume), stir and disperse, and obtain a diluted alkali solution, which is called component B.

[0168] (5) While stirring, add component B to the mixed solution of copper sulfate and polymer additive, component A. Control the addition and stirring speed to ensure uniform dispersion. Always pay attention to and maintain the transparency of the system until component B is added. The target product, transparent Bordeaux mixture, is obtained.

[0169] (6) Check the pH value of the transparent Bordeaux mixture product and adjust it to its weak alkaline range (pH = 6 to 7.5) if necessary.

[0170] The resulting transparent Bordeaux mixture can be used directly for spraying. Theoretically, this solution also contains approximately 35 grams of ammonium sulfate as a "byproduct." Unlike the industrial production of solid copper sulfate technical, which requires the treatment of ammonium sulfate-containing wastewater, this solution can be used as nitrogen fertilizer for plant growth, making full use of the ammonium sulfate.

[0171] Example 2.

[0172] Bordeaux mixture nanosuspension dispersions can be used to control citrus canker. Based on a water consumption of 200 kg / mu, the dosage of active ingredient equivalent to different dilution ratios for Bordeaux mixture suspension formulations registered in China varies significantly, ranging from approximately 90 g to 300 g / mu or even higher. Given the high efficacy of the transparent nano Bordeaux mixture, which has a particle size of less than 50 nm, to avoid phytotoxicity, the dosage of basic copper sulfate is reduced by 30%, to 60 g / mu.

[0173] This embodiment is based on the following chemical reaction formula:

[0174] 2CuSO4+2KOH→Cu2(OH)2SO4↓+K2SO4

[0175] The dosage of each component, the distribution ratio of dilution water, and the preparation method of the solution are listed in the following table:

[0176] How to do it:

[0177] ⑴ In a suitable container, dissolve anhydrous copper sulfate in 3 kg of water (accounting for 1.5% of the dilution water volume), stir to dissolve it, and obtain a transparent copper sulfate aqueous solution.

[0178] ⑵In another appropriate container, disperse CMC in 187 kg of water (accounting for 93.5% of the dilution water volume) to swell, then stir to dissolve it, then add other polymer additives, continue stirring to dissolve, and obtain a mixed aqueous solution of polymer additives.

[0179] ⑶ Under stirring, add the copper sulfate aqueous solution to the container containing the polymer additive aqueous solution, stir and disperse to form a transparent solution, and obtain a mixed solution of copper sulfate and polymer additive, which is called component A.

[0180] (4) In a suitable container, add potassium hydroxide to 10 kg of water (5% of the dilution water volume), stir and disperse to obtain a dilute alkali solution, called component B.

[0181] ⑸ While stirring, add solution B to the mixed solution A of copper sulfate and polymer additives in a continuous spraying manner, control the addition speed and stirring speed to make it evenly dispersed, pay attention to and maintain the transparency of the system, and obtain the target product - transparent Bordeaux mixture.

[0182] ⑹ Check the pH value of the product transparent Bordeaux mixture and adjust it to its weak alkalinity range of 6 to 7.5.

[0183] The resulting transparent Bordeaux mixture can be used directly for spraying. Theoretically, this solution also contains approximately 47 grams of potassium sulfate as a "by-product." Compared to the industrial production of basic copper sulfate solid technical, which requires the disposal of potassium sulfate-containing wastewater, this solution can be used as a potash fertilizer for plant growth, making full use of the material.

[0184] Example 3.

[0185] Bordeaux mixture nano-suspension dispersions can be used to control downy mildew in grapes. Based on a water consumption of 150 kg / mu, the dosage of the active ingredient equivalent to different dilution ratios for Bordeaux mixture suspension formulations registered in China varies significantly, ranging from approximately 60 to 280 g / mu. Considering the high efficacy of the small particle size of the transparent nano-Bordeaux mixture prepared in this invention, the dosage of basic copper sulfate is set at 60 g / mu to avoid phytotoxicity.

[0186] This embodiment uses a mixture of ammonium hydroxide and potassium hydroxide in different molar ratios, and the molecular ratio is based on the following chemical reaction formula:

[0187] 2CuSO4+2KOH→Cu2(OH)2SO4↓+K2SO4

[0188] 3CuSO4+6NH4OH→Cu3(OH)4(SO4)2↓+2(NH4)2SO4+2H2O

[0189] The dosage of each component, the distribution ratio of dilution water, and the preparation method of the solution are listed in the following table:

[0190] How to do it:

[0191] ⑴ In a suitable container, dissolve anhydrous copper sulfate in 3 kg of water (accounting for 2% of the dilution water volume), stir to dissolve it, and obtain a transparent copper sulfate aqueous solution.

[0192] ⑵In another appropriate container, add the polymer additives into 137 kg of water (accounting for 91.3% of the dilution water) in sequence, stir and dissolve to obtain a mixed aqueous solution of the polymer additives.

[0193] ⑶ Under stirring, add the copper sulfate aqueous solution to the container containing the polymer additive aqueous solution, stir and disperse to form a transparent solution, and obtain a mixed solution of copper sulfate and polymer additive, which is called component A.

[0194] (4) In another suitable container, add potassium hydroxide in batches to 10 kg of water (accounting for 6.7% of the dilution water) and stir to dissolve. Then add ammonium hydroxide and stir to disperse to obtain an aqueous solution of mixed alkali, referred to as component B.

[0195] (5) While stirring, gradually add Solution B to the copper sulfate and polymer additive mixture Solution A by continuous spraying. Control the addition and stirring speeds to ensure uniform dispersion. Maintain transparency to obtain the target product—transparent Bordeaux mixture.

[0196] ⑹ Check the pH value of the product transparent Bordeaux mixture and adjust it to its weak alkalinity range of 6 to 7.5.

[0197] The resulting transparent Bordeaux mixture can be used directly for spraying. Theoretically, this solution also contains approximately 15 grams of potassium sulfate and 23 grams of ammonium sulfate as "by-products." Compared to the industrial production of basic copper sulfate solid technical, which requires the disposal of wastewater containing potassium sulfate and ammonium sulfate, this solution can be used as potash and nitrogen fertilizer for plant growth, making full use of its properties.

Claims

1. A transparent Bordeaux liquid nanosuspension, wherein the transparent Bordeaux liquid nanosuspension is a nanosuspension in which basic copper sulfate particles are suspended and dispersed in an aqueous polymer dispersant solution in a random coil morphology.

2. The transparent Bordeaux liquid nanosuspension according to claim 1, characterized in that: The size of the basic copper sulfate particles is below 100 nanometers.

3. The transparent Bordeaux liquid nanosuspension according to claim 1 or 2, characterized in that: The polymer dispersant in the form of random coils in water is compatible with basic copper sulfate.

4. The transparent Bordeaux liquid nanosuspension according to claim 3, characterized in that: The polymer dispersant in the form of random coils in water is one of the following: Polyvinylpyrrolidone; Polyvinyl alcohol; Sodium lauryl sulfate and its derivatives; Sodium carboxymethyl cellulose; Polyoxyethylene ethers and their derivatives; Amino silicone oil.

5. The transparent Bordeaux liquid nanosuspension according to claim 3, characterized in that: The polymer dispersant in the form of random coils in water is at least two of the following: Polyvinylpyrrolidone; Polyvinyl alcohol; Sodium lauryl sulfate and its derivatives; Sodium carboxymethyl cellulose; Polyoxyethylene ethers and their derivatives; Amino silicone oil.

6. The transparent Bordeaux liquid nanosuspension according to claim 1 or 2, characterized in that: The transparent Bordeaux liquid nano suspension uses pure water as a solvent.

7. The transparent Bordeaux liquid nanosuspension according to claim 6, characterized in that: The concentration of the transparent Bordeaux liquid nanosuspension is less than 1%.

8. The transparent Bordeaux liquid nanosuspension according to claim 6, characterized in that: The pH range of the transparent Bordeaux liquid nanosuspension is from weak acid to weak alkaline.

9. The transparent Bordeaux liquid nanosuspension according to claim 8, characterized in that: The pH range is 5.5-8.

10. The transparent Bordeaux liquid nanosuspension according to claim 8, characterized in that: The pH range is 6 to 7.

5.

11. A method for preparing a transparent Bordeaux liquid nanosuspension, comprising the following steps: 1) adding an aqueous solution of copper sulfate to an aqueous solution of a polymer dispersant, stirring and dispersing, and forming a transparent solution to obtain a mixed solution of copper sulfate and a polymer auxiliary agent, referred to as component A; the polymer dispersant exists in water in the form of a random coil structure; 2) Select an alkaline compound that reacts with copper sulfate and dissolve it in water to form a monomolecularly dispersed alkaline solution, which is called component B; 3) While stirring, add component B to component A, and control the adding speed and stirring speed to make it evenly dispersed to obtain a transparent Bordeaux liquid nanosuspension.

12. The preparation method according to claim 11, further comprising the steps of: 4) Check the pH value of the product transparent Bordeaux liquid nanosuspension and adjust it to be weakly acidic or weakly alkaline.

13. The preparation method according to claim 12, wherein the pH range is 5.5-8. The preparation method according to claim 12 , wherein the pH range is 6 to 7.

5.

15. The preparation method according to claim 11 or 12, wherein the base molecule of the base compound is sodium hydroxide, potassium hydroxide, ammonium hydroxide or calcium hydroxide.

16. The preparation method according to claim 11 or 12, characterized in that: The polymer dispersant is compatible with basic copper sulfate.

17. The preparation method according to claim 11 or 12, characterized in that: The polymer dispersant is at least one of the following: Polyvinylpyrrolidone; Polyvinyl alcohol; Sodium lauryl sulfate and its derivatives; Sodium carboxymethyl cellulose; Polyoxyethylene ethers and their derivatives; Amino silicone oil.

18. The preparation method according to claim 11 or 12, characterized in that: The polymer dispersant is at least two of the following: Polyvinylpyrrolidone; Polyvinyl alcohol; Sodium lauryl sulfate and its derivatives; Sodium carboxymethyl cellulose; Polyoxyethylene ethers and their derivatives; Amino silicone oil.

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