Slow-release composite algistat with algal inhibition and phosphorus removal functions as well as use method and application of slow-release composite algistat

Abstract

The invention belongs to the technical field of water environment restoration, and particularly relates to a slow-release composite algistat with algal inhibition and phosphorus removal functions and a using method and application thereof.The slow-release composite algistat is composed of an active algistat component, a polymer carrier, a phosphorus removal active component and a particle dispersing agent, the mass volume concentration of the active algistat component is 20-100 g / L, and the mass volume concentration of the polymer carrier is 20-100 g / L; the mass volume concentration of the polymer carrier is 5-50 g / L, the mass volume concentration of the phosphorus removal active component is 5-100 g / L, and the mass volume concentration of the particle dispersant is 2-20 g / L; according to the eco-friendly long-acting slow-release compound algistat and the scene adding method thereof, the efficient and more than 80-day long-acting treatment and prevention of blue-green algae for water bodies with different seasons and pollution degrees can be realized, and the ecological environment-friendly long-acting slow-release compound algistat has a wide application prospect. Meanwhile, the method has the outstanding advantages of reducing secondary pollution of nitrogen and phosphorus and promoting restoration of a microbial ecological system, is high in engineering applicability and has wide popularization and application prospects.

Description

Technical Field

[0001] This invention belongs to the field of water environment remediation technology, specifically relating to a slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions, as well as its usage and application. Background Technology

[0002] Eutrophication of lakes and the resulting harmful algal blooms are among the most serious water environmental problems globally. Cyanobacterial blooms not only damage the structure and function of aquatic ecosystems and lead to a decline in biodiversity, but the various algal toxins they produce also directly threaten drinking water safety, human health, and aquatic ecological security. Therefore, developing efficient, safe, and eco-compatible cyanobacterial control technologies is an urgent need to achieve continuous improvement in lake water quality and ensure ecological security.

[0003] Currently, the main technologies for controlling cyanobacterial blooms include physical, chemical, and biological methods. Physical methods, such as mechanical harvesting, are effective for localized and concentrated algal blooms, but they are costly and energy-intensive, and are generally only applicable to localized or concentrated blooms, making them unsuitable for large-scale spread. Chemical methods, such as the application of oxidizing algaecides like copper sulfate and hydrogen peroxide, are fast-acting, but their strong oxidizing properties cause widespread and irreversible damage to aquatic microbial communities while killing algae. They also pose multiple risks, including residual metal ions and secondary release of endogenous phosphorus and algal toxins due to algal cell lysis. Long-term use may exacerbate ecosystem degradation.

[0004] Compared to the methods mentioned above, allelopathic bio-algae suppression technology shows promising potential due to its specific mechanism of action and high environmental compatibility. Allelochemicals are secondary metabolites produced by plants or microorganisms that can specifically inhibit cyanobacterial growth by interfering with photosynthesis, disrupting cell structure, or inducing oxidative stress. These substances are generally easily biodegraded and are considered ideal candidates for developing environmentally friendly algaecides. However, directly applying allelochemicals to actual water bodies still faces two major technical bottlenecks: First, most allelochemicals have poor water solubility and are prone to rapid photodegradation or biodegradation in complex aquatic environments, resulting in a short effective period and difficulty in achieving long-term inhibition. Frequent application is often required to maintain the effect, increasing application costs and operational complexity. Second, if a single high-dose application is used to prolong the effect, it can easily lead to excessively high local concentrations, potentially causing toxicity to non-target aquatic organisms and animals, thus deviating from the original intention of eco-friendliness.

[0005] To overcome the aforementioned contradictions, slow-release technology has been introduced into the field of allelopathic algae suppression. Existing research largely focuses on loading single allelochemicals onto solid carriers such as sodium alginate and chitosan, then solidifying them into particles or microspheres through cross-linking. However, these solid slow-release formulations have significant limitations in practical applications: they tend to settle into bottom sediments after addition, making it difficult to maintain effective contact with cyanobacteria, which are mainly distributed on the water surface, severely impacting their spatial efficiency; simultaneously, their release kinetics primarily depend on the degradation rate of the carrier material, making it difficult to intelligently respond to and regulate based on the dynamic changes of cyanobacteria in the water. More critically, existing algae suppression technologies generally lack a scientific, systematic, and operable dosing guideline in practical engineering applications. Natural water bodies are highly dynamic heterogeneous systems, with significant spatiotemporal heterogeneity in cyanobacterial population density, physiological activity, and environmental background. In this context, insufficient dosage results in weak algae suppression effects, failing to curb algal blooms; while excessive dosage not only wastes reagents and increases costs but also poses unnecessary ecological risks. Therefore, establishing differentiated and precise dosing strategies that match the physicochemical properties, release patterns, and environmental requirements of algaecides for different application scenarios, such as high-density algal bloom outbreaks, low-density incubation periods, and winter recovery and prevention periods, is a key link in achieving efficient and safe governance and also a significant gap in the current technological field.

[0006] Therefore, the current field of cyanobacteria control urgently needs an innovative algae suppressant that can balance high efficiency, long-lasting effect, and ecological safety, and to establish a corresponding precise dosing method system based on different water body scenarios, in order to overcome the shortcomings of existing technologies in terms of efficacy and safety. Summary of the Invention

[0007] To address the technical shortcomings of existing algaecides, such as rapid degradation, short action period, high ecological risk, lack of phosphorus removal function, and lack of scenario-specific dosing guidance, this invention aims to provide a composite algaecide that combines algae suppression and phosphorus removal functions, is eco-friendly, and has a long-lasting, slow-release effect. This invention also provides differentiated and precise dosing methods for this composite algaecide under different seasons and algae densities to resolve the contradiction between the persistence of algae suppression effect, safety, and engineering applicability.

[0008] To achieve the above objectives, the present invention provides a slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions. The slow-release composite algaecide is composed of an active algae-inhibiting component, a polymeric carrier, a phosphorus-removing active component, and a particulate dispersant. In the slow-release composite algaecide, the mass-volume concentration of the active algae-inhibiting component is 20-100 g / L, the mass-volume concentration of the polymeric carrier is 5-50 g / L, the mass-volume concentration of the phosphorus-removing active component is 5-100 g / L, and the mass-volume concentration of the particulate dispersant is 2-20 g / L.

[0009] Preferably, the active algae-inhibiting component is one or more combinations of artemisinin, salicylic acid, tannic acid, oleic acid, linoleic acid, linolenic acid, palmitic acid, soybean meal acid, stearic acid, lactic acid, acetic acid, gallic acid, pyrogallol, tea polyphenols, protocatechuic acid, ferulic acid, and citric acid; the polymeric carrier is one or more combinations of polyaluminum chloride, polyacrylamide, chitosan, sodium alginate, carboxymethyl cellulose, carboxymethyl starch, hydroxyethyl cellulose, polylysine, polyaluminum ferric silicate, polyethyleneimine, and polyvinylpyridine; the phosphorus-removing active component is one or more combinations of calcium carbonate, magnesium carbonate, calcium chloride, magnesium chloride, ferric chloride, ferric sulfate, polyferric sulfate, and polyaluminum chloride; and the particulate dispersant is one or more combinations of gelatin, xanthan gum, sodium polyacrylate, sodium carboxymethyl cellulose, cellulose sulfonate, silicate, sodium tripolyphosphate, Tween 80, Span 80, and alkylamide betaine.

[0010] Preferably, the slow-release composite algaecide is a stable micro / nano microemulsion with a particle size distribution between 1 and 5 μm.

[0011] This invention also provides a method for using a slow-release composite algaecide that combines algae inhibition and phosphorus removal functions, comprising the following steps: Step 1: Prepare the above-mentioned slow-release compound algaecide; Step 2: Add the slow-release compound algaecide to the target water body. The concentration of the slow-release compound algaecide is 0.1%~5% (v / v). When the target water body is in the cyanobacteria incubation prevention period in winter and spring, the concentration of the slow-release compound algaecide is 0.1%~0.3% (v / v); when the target water body has cyanobacterial blooms in summer and autumn, the concentration of the slow-release compound algaecide is 0.3%~5% (v / v).

[0012] Preferably, in step 1, the process for preparing the sustained-release compound algaecide is as follows: When the active algae-inhibiting component does not contain hydrophobic components, the active algae-inhibiting component and the polymer carrier are mixed, and then the phosphorus-removing active component and the particulate dispersant are added sequentially under high-speed stirring. The mixture is stirred continuously at 25~60℃ for 30~60 minutes to obtain the slow-release composite algae inhibitor. When the active algae-inhibiting component contains hydrophobic components, a particulate dispersant with emulsifying function is selected. It is first mixed with the hydrophobic active algae-inhibiting component to form a dispersed phase, and then emulsified with an aqueous phase containing the polymer carrier under high shear. Subsequently, the phosphorus-removing active component and the remaining particulate dispersant are added, and the mixture is stirred continuously at 25~60℃ for 30~60 minutes to complete the coagulation process and obtain the slow-release composite algae inhibitor.

[0013] Preferably, the high-speed stirring speed is 300~800 rpm; the high-shear emulsification shear speed is 3000~10000 rpm, and the emulsification time is 5~30 minutes.

[0014] Preferably, in step 2, the addition method is direct point source addition or uniform spraying on the water surface.

[0015] Preferably, in step 2, when the target water body experiences cyanobacterial blooms during summer and autumn, and the density of the cyanobacterial blooms is 2 × 10⁻⁶, 3 cells / mL ~5 × 10 5 Within the range of cells / mL, the dosage concentration of the slow-release compound algaecide is 0.3%~0.5% (v / v); when the density of the cyanobacterial bloom is 5 × 10⁻⁶ cells / mL... 5 cells / mL ~1.5 × 10 6 Within the range of cells / mL, the dosage concentration of the slow-release compound algaecide is 0.5%~1% (v / v); when the density of the cyanobacterial bloom is ≥1.5 × 10⁻⁶ cells / mL... 6 The concentration of the slow-release compound algaecide is 1%~5% (v / v), with a concentration of cells / mL.

[0016] This invention also provides the application of the above-mentioned slow-release compound algaecide in the long-term prevention and control of cyanobacterial blooms. The slow-release compound algaecide is added to the target water body to make the algae inhibition time ≥80 days and the algae density inhibition rate ≥75%.

[0017] This invention also provides the application of the above-mentioned slow-release composite algaecide in the treatment of eutrophic water bodies.

[0018] The beneficial technical effects of the present invention are as follows: (1) The micro-nano-scale slow-release composite algaecide prepared by the complex coagulation method of the present invention significantly prolongs the action period of the active components, and the algae suppression efficiency can reach more than 80 days; (2) The components selected by the slow-release composite algaecide of the present invention are natural or environmentally friendly, have little interference with non-target microorganisms at the recommended concentration, and can promote the recovery of microbial communities; (3) The present invention sets a precise addition method to accurately match the season, algae density and addition concentration and method, avoiding the blind overuse of the agent, while ensuring an algae suppression rate of more than 75%, reducing the risk of secondary pollution from the source and saving costs; (4) The technical solution of the present invention has readily available raw materials, simple process and convenient operation, and provides clear and specific addition guidelines, which are suitable for the whole cycle management from prevention to treatment, and have the potential for large-scale engineering application and promotion. Attached Figure Description

[0019] Figure 1These are graphs showing the effects of different algaecides on algal density in lakes in Example 1 and Comparative Examples 1-8 of the present invention; wherein, (a) is a graph showing the algal density change of lake 1 in Experiment 1, (b) is a graph showing the algal density change of lake 2 in Experiment 1, (c) is a graph showing the algal density change of lake 3 in Experiment 1, and (d) is a graph showing the algal density change of lakes in Experiment 2.

[0020] Figure 2 These are graphs showing the effects of different algaecides on chlorophyll a in lakes in Example 1 and Comparative Examples 1-8 of the present invention; wherein, (a) is a graph showing the changes in chlorophyll a in lake 1 in Experiment 1, (b) is a graph showing the changes in chlorophyll a in lake 2 in Experiment 1, (c) is a graph showing the changes in chlorophyll a in lake 3 in Experiment 1, and (d) is a graph showing the changes in chlorophyll a in lakes in Experiment 2.

[0021] Figure 3 These are graphs showing the changes in the proportion of cyanobacteria in lakes by different algaecides in Example 1 and Comparative Examples 1-8 of the present invention; wherein, (a) is a graph showing the change in the proportion of cyanobacteria in lake 1 in Experiment 1, (b) is a graph showing the change in the proportion of cyanobacteria in lake 2 in Experiment 1, (c) is a graph showing the change in the proportion of cyanobacteria in lake 3 in Experiment 1, and (d) is a graph showing the change in the proportion of cyanobacteria in lakes in Experiment 2.

[0022] Figure 4 These are graphs showing the changes in total nitrogen in lakes caused by different algaecides in Example 1 and Comparative Examples 1-8 of the present invention; wherein, (a) is a graph showing the changes in total nitrogen in lake 1 in Experiment 1, (b) is a graph showing the changes in total nitrogen in lake 2 in Experiment 1, (c) is a graph showing the changes in total nitrogen in lake 3 in Experiment 1, and (d) is a graph showing the changes in total nitrogen in lakes in Experiment 2.

[0023] Figure 5 These are graphs showing the changes in total phosphorus in lakes caused by different algaecides in Example 1 and Comparative Examples 1-8 of the present invention; wherein, (a) is a graph showing the changes in total phosphorus in lake 1 in Experiment 1, (b) is a graph showing the changes in total phosphorus in lake 2 in Experiment 1, (c) is a graph showing the changes in total phosphorus in lake 3 in Experiment 1, and (d) is a graph showing the changes in total phosphorus in lakes in Experiment 2.

[0024] Figure 6 These are graphs showing the changes in the Shannon index of microbial diversity in lakes under different algae-inhibiting agents in Example 1 and Comparative Examples 1-8 of the present invention; wherein, (a) is a graph showing the changes in the Shannon index of microbial diversity in lake 1 in Experiment 1, (b) is a graph showing the changes in the Shannon index of microbial diversity in lake 2 in Experiment 1, (c) is a graph showing the changes in the Shannon index of microbial diversity in lake 3 in Experiment 1, and (d) is a graph showing the changes in the Shannon index of microbial diversity in lakes in Experiment 2. Detailed Implementation

[0025] This invention discloses a slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions, along with its application and usage method. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired result. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0026] In this invention, all the raw materials described can be obtained commercially or by known means, and unless otherwise specified, they all meet the requirements of standard chemical products.

[0027] Unless otherwise specified, the experimental methods used in this invention are all conventional methods.

[0028] To prepare an eco-friendly, long-lasting, and stable slow-release compound algaecide, this invention has undergone extensive research and experimental verification, including the composition and dosage of each component in the formulation. The resulting slow-release compound algaecide demonstrates that this eco-friendly, long-lasting, slow-release compound algaecide and its application method can achieve highly efficient, long-lasting (over 80 days) treatment and prevention of cyanobacteria in water bodies with different seasons and pollution levels. It also possesses significant advantages such as reducing secondary nitrogen and phosphorus pollution and promoting the restoration of the microbial ecosystem. It has strong engineering applicability and broad prospects for widespread application.

[0029] In this invention, the algae inhibition rate, total phosphorus removal rate, and total nitrogen removal rate after the slow-release compound algaecide is added to the target water body are calculated using the following formula: Removal rate (%) = [1 - (measured value of treatment group / measured value of control group)] × 100%; The control group consisted of parallel experimental groups that received an equal amount of deionized water.

[0030] Specifically, this invention provides a slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions, comprising an active algaecide component, a polymeric carrier, a phosphorus-removing active component, and a particulate dispersant. In the slow-release composite algaecide, the preferred mass-volume concentration of the active algaecide component is 20-100 g / L, for example, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, or 100 g / L; the preferred mass-volume concentration of the polymeric carrier is 5-50 g / L, for example, 5 g / L, 15 g / L, 25 g / L, 35 g / L, 45 g / L, or 50 g / L; and the preferred mass-volume concentration of the phosphorus-removing active component is 5-100 g / L, for example, 5 g / L, 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, or 60 g / L. The particulate dispersant concentrations are 2 to 20 g / L, for example, 2 g / L, 5 g / L, 10 g / L, 15 g / L, and 20 g / L. The prepared slow-release composite algaecide is a stable micro / nano microemulsion with a particle size distribution between 1 and 5 μm. In this invention, the active algae-inhibiting component is preferably one or a combination of artemisinin, salicylic acid, tannic acid, oleic acid, linoleic acid, linolenic acid, palmitic acid, soybean meal acid, stearic acid, lactic acid, acetic acid, gallic acid, pyrogallic acid, tea polyphenols, protocatechuic acid, ferulic acid, and citric acid. The active algae-inhibiting component in this invention mainly inhibits the growth and proliferation of algal cells by synergistically destroying them through physical dissolution, chemical acidification, and biochemical interference.

[0031] The polymeric carrier is preferably one or a combination of polyaluminum chloride, polyacrylamide, chitosan, sodium alginate, carboxymethyl cellulose, carboxymethyl starch, hydroxyethyl cellulose, polylysine, polyaluminum ferric silicate, polyethyleneimine, and polyvinylpyridine salt. In this invention, the polymeric carriers are all long-chain polymers. During the complex condensation process, they form a three-dimensional network gel through the interaction between molecular chains, thereby loading the active ingredients. Furthermore, the polymeric carriers possess abundant functional groups (-OH, -COOH), enabling them to target negatively charged algal cells via electrostatic adsorption and to immobilize metal ions (such as Ca) through coordination bonds. 2+ Fe 3+ This enhances the stability of the system.

[0032] The phosphorus removal active component is preferably one or a combination of calcium carbonate, magnesium carbonate, calcium chloride, magnesium chloride, ferric chloride, ferric sulfate, polyferric sulfate, and polyaluminum chloride. The preferred particulate dispersant is one or a combination of gelatin, xanthan gum, sodium polyacrylate, sodium carboxymethyl cellulose, cellulose sulfonate, silicate, sodium tripolyphosphate, Tween 80, Span 80, and alkylamide betaine (carbon number 12-18).

[0033] In some embodiments of the present invention, the particulate dispersant may also be sodium dodecylbenzenesulfonate or hexadecyltrimethylammonium bromide.

[0034] In this invention, the component strategy employed in the sustained-release composite algaecide is as follows: the active algaecide component, as the core functional material, can directly inhibit cyanobacterial growth through mechanisms such as disrupting algal cell membranes and interfering with their physiological metabolism; the polymer carrier, as the sustained-release framework and targeting platform, effectively encapsulates and loads the active algaecide component and the phosphorus-removing active component through a complex coagulation / embedding process, forming micro- and nano-particles. This carrier not only controls the slow release of active substances, but its own positive charge can also specifically adsorb onto the negatively charged surface of cyanobacterial cells, achieving efficient enrichment of the algaecide components at the site of action, thereby significantly improving utilization efficiency and extending the duration of action; except... As an environmental regulator and structural enhancer, the phosphorus active component can form precipitates with phosphate ions in water, directly removing key nutrients for algal proliferation and synergistically inhibiting algal blooms from the root. On the other hand, the calcium, iron, and other polyvalent cations it releases can interact with the polymer carrier chains, making the microsphere structure more compact and stable, thereby further enhancing the slow-release performance of the entire system. The particulate dispersant, as a system stabilizer and release regulator, ensures that the active ingredients and polymer carriers are uniformly dispersed in the solution by constructing a uniform dispersion system, forming a stable microemulsion and preventing aggregation or sedimentation during storage and use.

[0035] This invention also provides a method for using the above-mentioned slow-release compound algaecide for long-term prevention and control of cyanobacterial blooms and treatment of eutrophic water bodies, including the following steps: Step 1: Prepare the above-mentioned slow-release composite algaecide; when the active algaecide component does not contain hydrophobic components, first dissolve the active algaecide component and the polymer carrier, and add the phosphorus removal active component under high-speed stirring at a speed preferably of 300~800 rpm to obtain a microemulsion. Then add the particulate dispersant to the microemulsion and stir continuously at 25~60℃ for 30~60 minutes to form a stable slow-release composite algaecide through the complex coagulation method. When the active algae-inhibiting component contains hydrophobic ingredients, a particulate dispersant with emulsifying function is selected. It is first mixed with the hydrophobic active algae-inhibiting component to form a dispersed phase, and then emulsified with an aqueous phase containing a polymer carrier under high shear. The shear rate of the high shear emulsification is 3000~10000 rpm, and the emulsification time is 5~30 minutes. Then, the phosphorus removal active component and the remaining particulate dispersant are added, and the mixture is stirred continuously at 25~60℃ for 30~60 minutes to complete the re-coagulation process and obtain the slow-release composite algae inhibitor.

[0036] Step 2: Add the slow-release compound algaecide to the target water body directly through point source application or uniform spraying on the water surface. The preferred concentration of the slow-release compound algaecide is 0.1%~5% (v / v). When the target water body is in the cyanobacteria hatching prevention period during winter and spring, the preferred concentration of the slow-release compound algaecide is 0.1%~0.3% (v / v), for example, 0.1% (v / v), 0.2% (v / v), or 0.3% (v / v). When the target water body experiences cyanobacterial blooms in summer and autumn, the concentration of the slow-release compound algaecide is 0.3%~5% (v / v). Specifically, when the cyanobacterial bloom is low-density (density range specifically 2 × 10⁻⁶), the concentration of the slow-release compound algaecide is 0.3%~5% (v / v). 3 cells / mL ~5 × 10 5 The preferred concentration of the slow-release compound algaecide is 0.3%~0.5% (v / v), for example, 0.3% (v / v), 0.4% (v / v), or 0.5% (v / v); when the cyanobacterial bloom is of medium density (specifically within the density range of 5 × 10⁻⁶ cells / mL), the concentration of the algaecide is 0.3%~0.5% (v / v), for example, 0.3% (v / v), 0.4% (v / v), or 0.5% (v / v). 5 cells / mL ~1.5 × 10⁻⁶ 6 The preferred concentration of the slow-release compound algaecide is 0.5%~1% (v / v), for example, 0.5% (v / v), 0.6% (v / v), 0.7% (v / v), 0.8% (v / v), 0.9% (v / v), or 1% (v / v); when the cyanobacterial bloom is high-density (specifically, a density range of ≥1.5 × 10⁻⁶ cells / mL), the concentration can be adjusted accordingly. 6 The preferred concentration of the slow-release compound algaecide is 1% to 5% (v / v), for example, 1% (v / v), 2% (v / v), 3% (v / v), 4% (v / v), or 5% (v / v). In the concentration of the slow-release compound algaecide, the denominator v is the volume of the target water body, and the numerator v is the volume of the slow-release compound algaecide.

[0037] Example 1 This embodiment provides an eco-friendly, long-acting, sustained-release compound algaecide, with the following formulation: Active algae-inhibiting components: artemisinin, concentration 50 g / L; gallic acid, concentration 50 g / L; Polymer carrier: chitosan, concentration 20 g / L; Phosphorus removal active component: calcium chloride, concentration 50 g / L; Particulate dispersant: gelatin, concentration 10 g / L.

[0038] The preparation method of the above-mentioned sustained-release compound algaecide provided in this embodiment is as follows: (1) Preparation of solution A: Weigh 20 g of chitosan and dissolve it in a 1% (w / v) acetic acid solution. Stir until completely dissolved to prepare a polymer carrier solution. Then add artemisinin and gallic acid and continue stirring until the active components are completely and evenly dispersed to obtain suspension A.

[0039] (2) Preparation of microemulsion B: Add 50 g of calcium chloride to suspension A under high-speed stirring (500 rpm) and continue stirring until a uniform and stable suspension B is formed.

[0040] (3) Molding and stabilization: 10 g of gelatin was added to microemulsion B under high-speed stirring (500 rpm) and stirred continuously at 60°C for 45 minutes to form a stable micro-nano microemulsion, which is the eco-friendly long-acting sustained-release composite algaecide (ASAs).

[0041] (4) Product characterization: The obtained algae inhibitor is a milky white to light yellow, uniform and viscous micro-nano suspension with a particle size distribution mainly concentrated between 1 and 3 μm, and has good kinetic stability.

[0042] Example 2 This embodiment provides an eco-friendly, long-acting, sustained-release compound algaecide, with the following formulation: Active algae-inhibiting components: linoleic acid, concentration 20 g / L; oleic acid, concentration 20 g / L; Polymer carrier: polyacrylamide, concentration 25 g / L; Phosphorus removal active component: calcium chloride, concentration 50 g / L; Particulate dispersants: Tween 80, concentration 15 g / L; xanthan gum, concentration 5 g / L.

[0043] The preparation method of the above-mentioned sustained-release composite algaecide provided in this embodiment is as follows: (1) Preparation of aqueous phase A: Weigh 25 g of polyacrylamide, add it to deionized water, heat and stir until completely dissolved to obtain solution A.

[0044] (2) Preparation of oil phase B: Mix 20 g linoleic acid, 20 g oleic acid and 15 g Tween 80 in a beaker, heat to 40°C and stir gently to form a homogeneous oil phase mixture.

[0045] (3) Using a high-shear dispersion emulsifier, at a high-speed shear of 8000 rpm, slowly add oil phase B to water phase A and continue shear emulsification at high speed for 15 minutes until a milky white primary emulsion C is formed.

[0046] (4) Preparation of microemulsion D: Under high-speed stirring (500 rpm), add an aqueous solution of calcium chloride to the primary emulsion C and continue stirring until a composite microemulsion D is formed.

[0047] (5) Molding and stabilization: Under high-speed stirring (500 rpm), 5 g xanthan gum was added to microemulsion D and stirred continuously at 50°C for 50 minutes to form a stable micro-nano microemulsion, which is the eco-friendly long-acting sustained-release composite algaecide.

[0048] (6) Product characterization: The obtained algae inhibitor is a milky white and uniform emulsion with a particle size distribution mainly between 1 and 5 μm.

[0049] Example 3 This embodiment provides an eco-friendly, long-acting, sustained-release compound algaecide, with the following formulation: Active algae-inhibiting components: lactic acid, concentration 30 g / L; palmitic acid, concentration 20 g / L; Polymer carrier and phosphorus removal active component: polyaluminum chloride, concentration 25 g / L; Particulate dispersants: Tween 80, concentration 8 g / L; gelatin, concentration 10 g / L.

[0050] The preparation method of the above-mentioned sustained-release composite algaecide provided in this embodiment is as follows: (1) Preparation of aqueous phase A: Weigh 25 g of polyaluminum chloride and slowly add lactic acid solution under stirring to obtain aqueous phase A, which is then kept at room temperature.

[0051] (2) Preparation of molten oil phase B: Weigh 20 g of palmitic acid and 8 g of Tween 80 into a beaker. Place the beaker in a water bath at 65-70°C and stir continuously until the palmitic acid is completely melted and forms a homogeneous and transparent oil phase mixture B with Tween 80.

[0052] (3) Using a high-shear dispersing emulsifier, while keeping the agitator running, slowly and dropwise add the molten oil phase B to the aqueous phase A. After the addition is complete, immediately increase the speed of the emulsifier to 10,000 rpm and continue shear emulsification at this high speed for 15 minutes to obtain microemulsion C.

[0053] (4) Molding and stabilization: 10 g of gelatin was added to microemulsion C under high-speed stirring (500 rpm) and stirred continuously at 50°C for 50 minutes to form a stable micro-nano microemulsion, which is the eco-friendly long-acting slow-release composite algaecide.

[0054] (5) Product characterization: The obtained algae inhibitor is a light yellow micro-nano suspension with a particle size distribution mainly between 3 and 5 μm.

[0055] Example 4 This embodiment provides an eco-friendly long-acting sustained-release compound algaecide, which differs from Example 1 in that the active algaecide components are tea polyphenols and tannic acid, the polymer carrier is chitosan, the phosphorus removal active components are calcium chloride and ferric sulfate, the particulate dispersant is sodium carboxymethyl cellulose, and the remaining steps are the same as in Example 1.

[0056] Example 5 This embodiment provides an eco-friendly long-acting sustained-release composite algaecide, which differs from Example 1 in that the active algaecide component is citric acid, the polymer carrier is polyethyleneimine and polyaluminum ferric silicate, the phosphorus removal active component is ferric chloride, the particulate dispersant is sodium polyacrylate, and the remaining steps are the same as in Example 1.

[0057] To verify the effectiveness of the present invention, the long-acting slow-release composite algaecide prepared in Examples 2-5 above was applied to the enclosure experiment of eutrophic water bodies. The dosage was 0.8% (v / v) and samples were taken and measured at 80 days and 120 days. The results are shown in Table 1.

[0058] Table 1. Long-lasting algae-inhibiting effects of the composite algaecides prepared in each embodiment.

[0059] As shown in Table 1, the long-acting slow-release composite algaecides prepared in Examples 2-5 of this invention all exhibit excellent long-acting performance. The algae inhibition rate of all formulations remained above 75% at 80 days and 120 days, and the total phosphorus removal rate was above 84% and the total nitrogen removal rate was above 72% at 80 days of addition.

[0060] Comparative Example 1 This comparative example provides a slow-release composite algaecide, which is basically the same as Example 1, except that calcium chloride in step (2) is not added, and calcium chloride is replaced with pure water to obtain a composite algaecide (ASAs-NCa) without calcium chloride components.

[0061] Comparative Example 2 This comparative example provides a slow-release composite algaecide, which is basically the same as Example 1, except that the gelatin in step (3) is not added, and pure water is replaced with gelatin to obtain a composite algaecide (AAs-NS) without gelatin components.

[0062] Comparative Example 3 This comparative example provides a slow-release composite algaecide, which is basically the same as Example 1, except that chitosan in step (1) is not added, and pure water is replaced with chitosan to obtain a composite algaecide (AAs-NCh) without chitosan components.

[0063] Comparative Example 4 This comparative example uses commercially available slow-release gallic acid algaecides (GSAs).

[0064] Comparative Example 5 This comparative example uses commercially available slow-release linoleic acid algaecides (LSAs).

[0065] Comparative Example 6 This comparative example uses commercially available slow-release hydrogen peroxide algaecides (HSAs).

[0066] Comparative Example 7 This comparative example uses commercially available slow-release coagulants and algaecides (SAs).

[0067] Comparative Example 8 This comparative example uses commercially available neutral artemisinin-based algaecides (MSAs).

[0068] Experiment 1: Three lakes with significant differences in perennial algal density and cyanobacterial bloom levels (lakes 1-3, with eutrophication decreasing in that order) were selected. A PVC ecological enclosure with a perimeter of 10 meters and a height of 2.2 meters was used to completely enclose the water bodies of lakes 1, 2, and 3, ensuring that the water volume within each enclosure was the same and that there was no hydraulic or material exchange with their respective external water bodies, only sharing temperature and climate, to simulate different governance scenarios. Lake 1 was the low-density group, with milder cyanobacterial blooms and lower eutrophication; Lake 2 was the medium-density group, with more severe cyanobacterial blooms in summer and higher eutrophication; and Lake 3 was the high-density group, with severe cyanobacterial blooms in summer and extremely high eutrophication.

[0069] Dosing scheme: The following algaecides were added to the enclosed areas of each lake: the composite algaecides (ASAs) prepared in Example 1, the calcium chloride-free composite algaecides (ASAs-NCa) of Comparative Example 1, the gelatin-free composite algaecides (AAs-NS) of Comparative Example 2, the chitosan-free composite algaecides (AAs-NCh) of Comparative Example 3, the slow-release gallic acid algaecides (GSAs) of Comparative Example 4, the slow-release linoleic acid algaecides (LSAs) of Comparative Example 5, the slow-release hydrogen peroxide algaecides (HSAs) of Comparative Example 6, the slow-release coagulant algaecides (SAs) of Comparative Example 7, and the neutral artemisinin algaecides (MSAs) of Comparative Example 8. High-density groups were added at high concentrations (2%, v / v); medium-density groups at medium concentrations (0.8%, v / v); and low-density groups at low concentrations (0.4%, v / v). The experiment lasted for 80 days, and various indicators were monitored.

[0070] Sampling plan: Water samples were taken from the enclosures of ASAs, ASAs-NCa, ASAs-NS, ASAs-NCh, GSAs, LSAs, HSAs, SAs, and MSAs at 1, 3, 5, 7, 10, 15, 20, 30, 50, and 80 days after the addition of different compound algaecides. Algal density, cyanobacteria ratio, chlorophyll a, TN (total nitrogen), TP (total phosphorus), and microbial diversity were measured.

[0071] Effect verification: such as Figure 1 and Figure 2As shown, on the 80th day after addition, the algal density inhibition rate of the ASAs treatment group in Example 1 was as high as 75% or more; the ASAs treatment group significantly reduced the growth of chlorophyll a in the lake, with chlorophyll a values ​​of 29.8~51.7 μg / L (lake 1), 59.5~103.4 μg / L (lake 2) and 89.5~134.1 μg / L (lake 3) from 20 to 80 days, which were significantly lower than those of the control group (358.9~808.8 μg / L (lake 1), 769.3~1614.9 μg / L (lake 2) and 907.7~1874.9 μg / L (lake 3)) (P<0.05); and no secondary algal proliferation was observed throughout the experimental period, demonstrating excellent long-term effectiveness. Compared to the ASAs treatment group, the ASAs-NCa treatment group in Comparative Example 1 showed a significantly shorter duration of algal suppression compared to the ASAs treatment group, with algal density and chlorophyll a levels significantly higher in the later stages of the experiment. The AAs-NS treatment group in Comparative Example 2 rapidly lost its algal suppression effect after addition, failing to achieve long-term algal suppression. The algal suppression effect and persistence of the AAs-NCh treatment group in Comparative Example 3 were significantly lower than those of the complete ASAs treatment group, particularly weak in suppressing cyanobacteria. The GSAs, LSAs, HSAs, SAs, and MSAs added in Comparative Examples 4-8 all showed a significant rebound in algal density and chlorophyll a in the later stages of the experiment (20-80 days), failing to suppress secondary cyanobacterial blooms. Among them, the MSAs treatment group showed the fastest decline in effect, while the SAs treatment group had almost no algal suppression effect.

[0072] Meanwhile, in the later stages of the experiment, such as Figure 4-5 In the later stages of the experiment, the total nitrogen and total phosphorus in the ASAs treatment group decreased significantly (p<0.05). After 20 days, the total nitrogen and total phosphorus in the ASAs treatment group were basically the same as or slightly lower than at the beginning of the experiment, significantly lower than the control group and the SAs treatment group (p<0.05), and also lower than other algaecide groups (the remaining comparative groups). The results indicate that, in a preventative scenario, the complete algaecide system of this invention has excellent long-term preventative ability and eco-friendliness at low concentrations.

[0073] Figure 6 As shown, the microbial diversity in the ASAs treatment group was the highest compared to all other treatment groups after the experiment, promoting the recovery of microbial diversity, increasing from 3.3 at the beginning of the experiment to 7.15 at the end. This indicates that the ASAs treatment group can not only effectively prevent cyanobacterial resurgence and blooms, but also prevent cyanobacteria from becoming the dominant species through the recovery and increase of microbial diversity, demonstrating a strong ability to prevent cyanobacterial blooms.

[0074] Experiment 2: An experiment was conducted in early March (the period for preventing cyanobacterial blooming) within a PVC ecological enclosure of a severely eutrophic lake. Dosing regimen: The following algaecides were added: the composite algaecides (ASAs) prepared in Example 1, the calcium chloride-free composite algaecides (ASAs-NCa) of Comparative Example 1, the gelatin-free composite algaecides (AAs-NS) of Comparative Example 2, the chitosan-free composite algaecides (AAs-NCh) of Comparative Example 3, the sustained-release gallic acid algaecides (GSAs) of Comparative Example 4, the sustained-release linoleic acid algaecides (LSAs) of Comparative Example 5, the sustained-release hydrogen peroxide algaecides (HSAs) of Comparative Example 6, the sustained-release coagulant algaecides (SAs) of Comparative Example 7, and the neutral artemisinin algaecides (MSAs) of Comparative Example 8. A single preventative addition was made using an extremely low concentration (0.2%, v / v), and the experiment lasted for 120 days.

[0075] Sampling plan: Water samples were taken from the enclosures of ASAs, ASAs-NCa, ASAs-NS, ASAs-NCh, GSAs, LSAs, HSAs, SAs, and MSAs on days 1, 10, 20, 30, 60, 90, and 120 after the addition of different compound algaecides. Algal density, cyanobacteria ratio, chlorophyll a, TN (total nitrogen), TP (total phosphorus), and microbial diversity were measured.

[0076] Effect verification: such as Figure 1-3 As shown, by the end of the experiment, the algal density and cyanobacteria ratio in the ASAs-treated group of Example 1 were significantly lower than those in the blank control group, and the increase in chlorophyll a was effectively controlled. Except for the SAs-treated group, the addition of other different algicides had varying degrees of negative impact on the increase in algal density and inhibited the recovery of cyanobacteria. However, the ASAs-treated group had the strongest inhibitory effect on the increase in algal density, and the cyanobacteria ratio was the lowest at the end of the experiment. The ASAs-treated group had the most significant inhibitory effect on cyanobacteria recovery, and its inhibitory effect on cyanobacteria recovery was significantly higher than that of the control group and other algicides (p<0.05).

[0077] like Figure 4-5 As shown, the total nitrogen and total phosphorus in the ASAs treatment group decreased significantly in the later stages of the experiment (p<0.05). After 20 days, the total nitrogen and total phosphorus in the ASAs treatment group were basically the same as or slightly lower than at the beginning of the experiment, significantly lower than the control group and the SAs treatment group (p<0.05), and also lower than other algaecide groups. The results indicate that, in a preventative scenario, the complete algaecide system of this invention has excellent long-term preventative ability and eco-friendliness at low concentrations.

[0078] Figure 6 As shown, the microbial diversity of the ASAs treatment group showed a steady upward trend during the experiment, reaching a maximum of 7.15 from 3.3, indicating that the low-dose addition strategy effectively inhibited cyanobacterial resurgence while maintaining and promoting the health and stability of the aquatic ecosystem.

[0079] In summary, during the winter and spring cyanobacteria incubation period, the preventative application of extremely low concentrations of ASAs (Experiment 2) effectively suppressed the increase in algal density and chlorophyll a, and kept the cyanobacteria ratio at a low level. During the summer cyanobacteria bloom, through a differentiated application strategy (Experiment 1), the ASAs treatment group demonstrated excellent long-term algal suppression performance over the 80-day experimental period, with an algal density inhibition rate of over 75%, and effectively prevented secondary algal blooms. In both of these periods, ASAs treatment significantly reduced the concentrations of total nitrogen and total phosphorus in the water body in the later stages, and promoted the rapid recovery of microbial diversity to or even above the initial levels, demonstrating the dual advantages of reducing secondary pollution and promoting ecological balance. This indicates that the algaecide prepared in this invention also has significant phosphorus removal function, effectively reduces the nutrient load of the water body, and exhibits eco-friendly characteristics that promote the recovery of microbial diversity.

[0080] The data from Example 1 and Comparative Examples 1-8 confirm the advanced nature and necessity of the technical solution of the composite algaecide of the present invention, which integrates algae inhibition, phosphorus removal, slow release, and stabilization functions. Furthermore, the absence of any key component or the simplification of its function will lead to a significant decrease in the final effect.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions, characterized in that, The slow-release composite algaecide is composed of active algaecide components, a polymer carrier, phosphorus removal active components, and a particulate dispersant. In the sustained-release composite algaecide, the mass-volume concentration of the active algaecide component is 20-100 g / L, the mass-volume concentration of the polymer carrier is 5-50 g / L, the mass-volume concentration of the phosphorus removal active component is 5-100 g / L, and the mass-volume concentration of the particulate dispersant is 2-20 g / L.

2. The slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions as described in claim 1, characterized in that, The active algae-inhibiting component is one or more combinations of artemisinin, salicylic acid, tannic acid, oleic acid, linoleic acid, linolenic acid, palmitic acid, soybean meal acid, stearic acid, lactic acid, acetic acid, gallic acid, pyrogallol, tea polyphenols, protocatechuic acid, ferulic acid, and citric acid; the polymeric carrier is one or more combinations of polyaluminum chloride, polyacrylamide, chitosan, sodium alginate, carboxymethyl cellulose, carboxymethyl starch, hydroxyethyl cellulose, polylysine, polyaluminum ferric silicate, polyethyleneimine, and polyvinylpyridine; the phosphorus-removing active component is one or more combinations of calcium carbonate, magnesium carbonate, calcium chloride, magnesium chloride, ferric chloride, ferric sulfate, polyferric sulfate, and polyaluminum chloride; the particulate dispersant is one or more combinations of gelatin, xanthan gum, sodium polyacrylate, sodium carboxymethyl cellulose, cellulose sulfonate, silicate, sodium tripolyphosphate, Tween 80, Span 80, and alkylamide betaine.

3. The slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions as described in claim 1, characterized in that, The slow-release composite algaecide is a stable micro / nano microemulsion with a particle size distribution between 1 and 5 μm.

4. A method for using a slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions, characterized in that, Includes the following steps: Step 1: Prepare the sustained-release composite algaecide according to any one of claims 1-3; Step 2: Add the slow-release compound algaecide to the target water body. The concentration of the slow-release compound algaecide is 0.1%~5% (v / v). When the target water body is in the cyanobacteria incubation prevention period in winter and spring, the concentration of the slow-release compound algaecide is 0.1%~0.3% (v / v); when the target water body has cyanobacterial blooms in summer and autumn, the concentration of the slow-release compound algaecide is 0.3%~5% (v / v).

5. The method of using the slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions as described in claim 4, characterized in that, In step 1, the process for preparing the sustained-release compound algaecide is as follows: When the active algae-inhibiting component does not contain hydrophobic components, the active algae-inhibiting component and the polymer carrier are mixed, and then the phosphorus-removing active component and the particulate dispersant are added sequentially under high-speed stirring. The mixture is stirred continuously at 25~60℃ for 30~60 minutes to obtain the slow-release composite algae inhibitor. When the active algae-inhibiting component contains hydrophobic components, a particulate dispersant with emulsifying function is selected. It is first mixed with the hydrophobic active algae-inhibiting component to form a dispersed phase, and then emulsified with an aqueous phase containing the polymer carrier under high shear. Subsequently, the phosphorus-removing active component and the remaining particulate dispersant are added, and the mixture is stirred continuously at 25~60℃ for 30~60 minutes to complete the coagulation process and obtain the slow-release composite algae inhibitor.

6. The method of using the slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions as described in claim 5, characterized in that, The high-speed stirring speed is 300~800 rpm; the high-shear emulsification shear rate is 3000~10000 rpm, and the emulsification time is 5~30 minutes.

7. The method of using the slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions as described in claim 4, characterized in that, In step 2, the addition method is either direct addition from a point source or uniform spraying on the water surface.

8. The method of using a slow-release composite algaecide with both algae-inhibiting and phosphorus-removing functions as described in claim 4, wherein in step 2, when the target water body experiences cyanobacterial blooms in summer and autumn, and the density of the cyanobacterial bloom is 2 × 10⁻⁶... 3 cells / mL ~5 × 10 5 Within the range of cells / mL, the dosage concentration of the slow-release compound algaecide is 0.3%~0.5% (v / v); when the density of the cyanobacterial bloom is 5 × 10⁻⁶ cells / mL... 5 cells / mL ~1.5 × 10 6 Within the range of cells / mL, the dosage concentration of the slow-release compound algaecide is 0.5%~1% (v / v); when the density of the cyanobacterial bloom is ≥1.5 × 10⁻⁶ cells / mL... 6 The concentration of the slow-release compound algaecide is 1%~5% (v / v), with a concentration of cells / mL.

9. The application of the slow-release compound algaecide according to any one of claims 1-3 in the long-term control of cyanobacterial blooms, characterized in that, The slow-release compound algaecide is added to the target water body to inhibit algae for ≥80 days and inhibit algae density by ≥75%.

10. The application of the slow-release compound algaecide according to any one of claims 1-3 in the treatment of eutrophic water bodies.

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