Allelopathic substance sustained-release agent and its preparation method and application

Abstract

The present invention relates to an allelopathic substance slow-release agent and its preparation method and application, and belongs to the technical field of water environment treatment. The technical problem solved by the present invention is to provide a preparation method of an allelopathic substance slow-release agent with good slow-release and algae-inhibiting effects. The method extracts magnolia grandiflora leaves and barley straw powder with water to obtain an extract; sodium alginate, magnolia grandiflora leaves and barley straw powder are added to the extract, and stirred until the sodium alginate is completely dissolved to obtain a sodium alginate solution; the sodium alginate solution is dripped dropwise into a calcium chloride solution, stirred, and allowed to stand after the dropwise addition is completed to obtain gel balls; taken out, washed, and an allelopathic substance slow-release agent is obtained. The allelopathic substance slow-release agent of the present invention can release allelopathic substances in a sustainable low dose to inhibit algae, and the dosage is low. Only 50 g-100 g is required per ton of water to achieve algae-inhibiting effects, and the slow-release effect is good. A good inhibitory effect can also be achieved 21 days after the administration. It can be used as a slow-release algaecide and expanded to actual rivers and lakes.

Description

Technical Field

[0001] The invention relates to an allelopathic substance slow-release agent and a preparation method and application thereof, belonging to the technical field of water environment treatment. Background Art

[0002] In recent years, outbreaks of cyanobacteria blooms caused by eutrophication have caused numerous problems. Blooms can deteriorate the water environment, kill other aquatic organisms, and further degrade the environment. Currently, cyanobacteria bloom control technologies can be categorized into physical, chemical, and biological control. Chemical control technologies are primarily used for emergency response to cyanobacteria blooms, primarily using chemical algaecides to eliminate them. However, most chemical algaecides are prone to secondary contamination of the water during their application.

[0003] Allelopathic effect refers to the interaction between plants through signal compounds, which is widely present in plant community systems. The allelochemicals involved in the formation of allelopathic effect are secondary metabolites in the growth process of plants. They are generally degraded under natural conditions and will not accumulate in the ecosystem, so they are ecologically safe. At present, many allelochemicals produced by aquatic plants have been shown to have a certain effect of inhibiting algae growth. However, when the water body has been severely eutrophicated or algae have already broken out, aquatic plants find it difficult to survive in it. Therefore, it is relatively difficult to rely solely on the allelochemicals released by aquatic plants to deal with algal turbidity in water bodies.

[0004] In addition to aquatic plants, terrestrial plants also possess allelopathic substances. Terrestrial plants have high biomass and abundant allelopathic substances. Currently, allelopathic substances from various terrestrial plants have been reported to have algae-inhibiting effects. However, the concentrations of allelopathic substances in plant materials are extremely low, and directly introducing plant materials into water bodies can significantly affect the aesthetics of the water. Therefore, the introduction of slow-release agents containing allelopathic substances can significantly reduce this impact and also significantly reduce the amount of agent introduced.

[0005] Patent CN106614556A discloses a method for preparing and applying a slow-release algaecide. This method combines phenolic acids with an encapsulation technique, selects biodegradable materials, and adjusts the pH of the required materials for encapsulation. While maintaining the allelopathic activity of the core encapsulated material, it slowly releases the allelopathic substances to inhibit algae in the water. However, this method is complex and costly, and the inhibitory effect of the prepared product, 0.2 g of the slow-release agent, when added to 50 mL of water with a low algae concentration, is only 70%. The dosage of the product is very large, and the algae inhibition effect is poor, making it difficult to expand its application to actual rivers and lakes. Furthermore, the slow-release agent needs to be repeatedly applied after 3-4 days of application, resulting in a poor slow-release effect. Summary of the Invention

[0006] In view of the above defects, the technical problem solved by the present invention is to provide a method for preparing a slow-release agent of allelopathic substances with good slow-release effect and good algae inhibition effect.

[0007] The preparation method of the allelopathic substance sustained-release agent of the present invention comprises the following steps:

[0008] 1) Extraction: extracting plant powder with water and concentrating by evaporation to obtain an extract; the plant is Magnolia grandiflora leaves and barley straw, and the weight ratio of Magnolia grandiflora leaves to barley straw is 0.5 to 2.0:1;

[0009] 2) Prepare the solution: Add sodium alginate and plant powder to the extract and stir until the sodium alginate is completely dissolved to obtain a sodium alginate solution; dissolve calcium chloride in water to obtain a calcium chloride solution;

[0010] 3) Preparation of gel spheres: Add sodium alginate solution dropwise into calcium chloride solution, stir, and allow to stand to obtain gel spheres.

[0011] 4) Post-processing: The gel balls are taken out and washed to obtain the allelopathic substance sustained-release agent.

[0012] In one embodiment of the present invention, the evaporation concentration is performed to a mass volume ratio of powder to extract of 0.2 to 1.2 g: 1 mL.

[0013] In a specific embodiment of the present invention, the evaporation concentration is performed to a mass volume ratio of the plant powder to the extract of 1 g: 1 mL.

[0014] In one embodiment of the present invention, in step 1), the magnolia leaf powder and the barley straw powder are mixed and then extracted with water to obtain an extract; or the magnolia leaf powder is extracted with water to obtain a magnolia leaf extract, and the barley straw powder is extracted with water to obtain a barley straw extract, and the two are mixed to obtain an extract.

[0015] In one embodiment of the present invention, the mass ratio of Magnolia grandiflora leaves to barley straw is 1:1.

[0016] In one embodiment of the present invention, in step 2), the amount of plant powder added is 1-10 g / 100 mL; the concentration of sodium alginate in the sodium alginate solution is 0.5-2.5 g / 100 mL; and the mass percentage concentration of calcium chloride in the calcium chloride solution is 1.5-2.5%.

[0017] In a specific embodiment of the present invention, in step 2), the amount of plant powder added to the sustained-release agent is 1-5 g / 100 mL; the concentration of sodium alginate in the sodium alginate solution is 1.5-2.0 g / 100 mL; and the mass percentage concentration of calcium chloride in the calcium chloride solution is 2%.

[0018] The second technical problem solved by the present invention is to provide a sustained-release agent for allelopathic substances.

[0019] The allelopathic substance slow-release agent of the present invention is prepared by the above-mentioned preparation method of the allelopathic substance slow-release agent. In the slow-release agent, the magnolia leaves and barley straw synergistically enhance the effect, so that it has a smaller dosage, a longer algae inhibition time, a simpler production process and a lower production cost.

[0020] The present invention also provides use of the allelopathic substance slow-release agent of the present invention in an algaecide.

[0021] The allelopathic substance slow-release agent of the present invention can be used as an algaecide to solve the problem of algae outbreak in severely eutrophic water bodies. Its slow-release function allows it to be administered once to achieve a continuous algae-inhibiting effect.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The allelopathic substance slow-release agent of the present invention can continuously release allelopathic substances in low doses to inhibit algae. The dosage is low, and only 50 g to 100 g is required per ton of water to achieve the algae inhibition effect. The slow-release effect is good, and a good inhibitory effect can be achieved 21 days after the administration. The agent can be used as a slow-release algaecide and expanded to actual rivers and lakes.

[0024] The preparation method of the allelopathic substance sustained-release agent of the present invention has simple process and low cost, is suitable for industrial large-scale production, and reduces the production cost of the sustained-release agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a graph showing the daily changes in chlorophyll content in each experimental group in Test Example 1 of the present invention.

[0026] Figure 2 This is a picture of the water color of three parallel groups on the 29th day of the experiment in Test Example 1 of the present invention, where a, b, and c are three parallel groups of water pictures, and each picture is from left to right the control group, 0.2 g group, 0.4 g group, 0.6 g group, and 0.8 g group.

[0027] Figure 3 This is a graph showing the daily changes in chlorophyll content in each experimental group in Test Example 2 of the present invention. DETAILED DESCRIPTION

[0028] The preparation method of the allelopathic substance sustained-release agent of the present invention comprises the following steps:

[0029] 1) Extraction: extracting plant powder with water and concentrating by evaporation to obtain an extract; the plant is Magnolia grandiflora leaves and barley straw, and the weight ratio of Magnolia grandiflora leaves to barley straw is 0.5 to 2.0:1;

[0030] 2) Prepare the solution: Add sodium alginate and plant powder to the extract and stir until the sodium alginate is completely dissolved to obtain a sodium alginate solution; dissolve calcium chloride in water to obtain a calcium chloride solution;

[0031] 3) Preparation of gel spheres: Add sodium alginate solution dropwise into calcium chloride solution, stir, and allow to stand to obtain gel spheres.

[0032] 4) Post-processing: The gel balls are taken out and washed to obtain the allelopathic substance sustained-release agent.

[0033] The method of the present invention is simple, does not require special equipment, and has low cost. The obtained allelopathic substance slow-release agent has good slow-release effect and good algae inhibition effect, and can be added in small amounts to obtain a longer algae inhibition time.

[0034] In one embodiment of the present invention, the evaporation concentration is performed to a mass volume ratio of powder to extract of 0.2 to 1.2 g: 1 mL.

[0035] In a specific embodiment of the present invention, the evaporation concentration is performed to a mass volume ratio of the plant powder to the extract of 1 g: 1 mL.

[0036] In one embodiment of the present invention, in step 1), the magnolia leaf powder and the barley straw powder are mixed and then extracted with water to obtain an extract; or the magnolia leaf powder is extracted with water to obtain a magnolia leaf extract, and the barley straw powder is extracted with water to obtain a barley straw extract, and the two are mixed to obtain an extract.

[0037] In one embodiment of the present invention, the mass ratio of Magnolia grandiflora leaves to barley straw is 1:1.

[0038] In one embodiment of the present invention, in step 2), the amount of plant powder added is 1-10 g / 100 mL; the concentration of sodium alginate in the sodium alginate solution is 0.5-2.5 g / 100 mL; and the mass percentage concentration of calcium chloride in the calcium chloride solution is 1.5-2.5%.

[0039] In a specific embodiment of the present invention, in step 2), the amount of plant powder added to the sustained-release agent is 1-5 g / 100 mL; the concentration of sodium alginate in the sodium alginate solution is 1.5-2.0 g / 100 mL; and the mass percentage concentration of calcium chloride in the calcium chloride solution is 2%.

[0040] The allelopathic substance slow-release agent of the present invention is prepared by the above-mentioned preparation method of the allelopathic substance slow-release agent. In the slow-release agent, the magnolia leaves and barley straw synergistically enhance the effect, so that it has a smaller dosage, a longer algae inhibition time, a simpler production process and a lower production cost.

[0041] The allelopathic substance slow-release agent of the present invention can be used as an algaecide to solve the problem of algae outbreak in severely eutrophic water bodies. Its slow-release function allows it to be administered once to achieve a continuous algae-inhibiting effect.

[0042] The specific embodiments of the present invention are further described below in conjunction with examples, but the present invention is not limited to the scope of the examples.

[0043] Example 1

[0044] The allelopathic substance sustained-release agent was prepared according to the following method:

[0045] (1) Pretreatment of Magnolia grandiflora and barley straw

[0046] The collected fallen leaves of Magnolia grandiflora and barley straw were washed and dried in an oven at 55°C. The two plants were crushed as much as possible and then pulverized in a grinder respectively. The powders of the two plants were sieved through a 120-mesh sieve to obtain powders of the two plants.

[0047] (2) Extraction of Magnolia grandiflora and barley straw

[0048] Weigh 100 g of each plant powder, add 1 L of pure water and soak for 48 h, filter, and evaporate and concentrate each filtrate to 100 mL to obtain the extraction mother liquor of the two plants.

[0049] (3) Preparation of allelopathic substance sustained-release agent

[0050] 50 mL of each of the two plant extracts were mixed, and 1.5 g of sodium alginate, 2 g of magnolia grandiflora powder, and 2 g of barley straw powder were added. The mixture was stirred until the sodium alginate was completely dissolved. The mixture was then added dropwise into a 2% calcium chloride solution to complex the sodium alginate into gel balls. The mixture was allowed to stand for 10 min, filtered, and washed with 200 mL of water to obtain the final allelopathic substance slow-release agent.

[0051] Comparative Example 1

[0052] The allelopathic substance sustained-release agent was prepared according to the following method:

[0053] (1) Magnolia grandiflora pretreatment

[0054] The collected fallen leaves of Magnolia grandiflora were washed, dried in an oven at 55°C, crushed as much as possible, and then put into a grinder for grinding, and passed through a 120-mesh sieve to obtain Magnolia grandiflora powder.

[0055] (2) Magnolia grandiflora extraction

[0056] Weigh 100 g of Magnolia grandiflora powder, add 1 L of pure water and soak for 48 h, filter, and evaporate the filtrate to 100 mL to obtain the Magnolia grandiflora extraction mother liquor.

[0057] (3) Preparation of allelopathic substance sustained-release agent

[0058] Measure 100 mL of the magnolia grandiflora extract mother liquor, add 1.5 g of sodium alginate and 4 g of magnolia grandiflora powder, and stir until the sodium alginate is completely dissolved. Pour the mixture dropwise into a 2% calcium chloride solution to complex the sodium alginate into gel balls. Let it stand for 10 min, filter it, and wash the gel balls with 200 mL of water to obtain the final allelopathic substance sustained-release agent.

[0059] Comparative Example 2

[0060] The allelopathic substance sustained-release agent was prepared according to the following method:

[0061] (1) Barley straw pretreatment

[0062] The collected barley straw was washed and dried in an oven at 55°C. The plant was crushed as much as possible and then placed in a grinder for grinding. The powder was passed through a 120-mesh sieve to obtain barley straw powder.

[0063] (2) Barley straw extraction

[0064] Weigh 100 g of barley straw powder, add 1 L of pure water and soak for 48 h, filter, and evaporate the filtrate to 100 mL to obtain the barley straw extraction mother liquor.

[0065] (3) Preparation of allelopathic substance sustained-release agent

[0066] Measure 100 mL of barley straw extraction mother liquor, add 1.5 g of sodium alginate and 4 g of barley straw powder, stir until the sodium alginate is completely dissolved, and add it dropwise into a 2% calcium chloride solution to complex the sodium alginate into gel balls. Let it stand for 10 min, filter it, and wash the gel balls with 200 mL of water to obtain the final allelopathic substance slow-release agent.

[0067] Test Example 1

[0068] Fifteen transparent organic glass columns with a diameter of 15 cm and a height of 60 cm were selected. 8.5 L of algae-turbidity water was added to each column. The dominant algae species in the water was Microcystis. The 15 water columns were divided into three groups. Different amounts of the allelochemical slow-release agent of Example 1 were added to each group. 500 mL of water sample was taken daily and 500 mL of algae-turbidity water was added. The changes in chlorophyll content in each group were monitored daily. The results are shown in Tables 1 and Figure 1 , the numerical unit in Table 1 is ppb.

[0069] Table 1 Daily chlorophyll content data of each experimental group

[0070]

[0071] The experimental results show that when equal amounts of algae solution were added for cultivation at the beginning of the experiment, chlorophyll concentrations varied significantly between the groups after two days. However, one week after the addition of the slow-release agent, chlorophyll concentrations in all experimental groups decreased significantly. By day 15, chlorophyll content in the group with 0.2 g of the agent began to increase. By day 21, chlorophyll content in all experimental groups had gradually increased.

[0072] Figure 2 The water color of the three parallel groups on day 29 of the experiment (from left to right) is similar across the three parallel groups, indicating good experimental reproducibility. The color gradually lightened with increasing doses of the sustained-release agent.

[0073] Test Example 2

[0074] Four transparent organic glass columns with a diameter of 15 cm and a height of 60 cm were selected, and 8.5 L of algae-turbid water was added to each column. The dominant algae species in the water was Microcystis. The four water columns were divided into a blank group, a magnolia group, a barley straw group, and a mixed group. Except for the blank group, no slow-release agent was added. The other groups were added with 0.6 g of the corresponding allelopathic substance slow-release agent. Among them, the magnolia group was added with the allelopathic substance slow-release agent of comparative example 1, the barley straw group was added with the allelopathic substance slow-release agent of comparative example 2, and the mixed group was added with the allelopathic substance slow-release agent of embodiment 1. 500 mL of water sample was taken out from each group every day, and 500 mL of algae-turbid water was newly added to monitor the changes in chlorophyll content in each group every day. The results are shown in Tables 2 and Figure 3 .

[0075] Table 2

[0076]

[0077] It can be seen that both the extracts of Magnolia grandiflora and barley straw have good inhibitory effects on algae growth, among which the inhibitory effect of Magnolia grandiflora is slightly better than that of barley straw, but the mixed solution of the two has the best effect, indicating that Magnolia grandiflora and barley straw can synergistically enhance their effectiveness and greatly improve the algae inhibition effect and slow-release effect.

Claims

1. A method for preparing a sustained-release allelopathic substance, characterized in that: The following steps are involved: 1) Extraction: extracting plant powder with water, and concentrating by evaporation until the mass volume ratio of plant powder to extract is 0.2-1.2 g:1 mL, thereby obtaining an extract; the plant is Magnolia grandiflora leaves and barley straw, and the weight ratio of Magnolia grandiflora leaves to barley straw is 0.5-2.0:1; 2) Prepare the solution: Add sodium alginate and plant powder to the extract and stir until the sodium alginate is completely dissolved to obtain a sodium alginate solution; dissolve calcium chloride in water to obtain a calcium chloride solution; the amount of plant powder added is 1-10 g / 100 mL; the sodium alginate concentration in the sodium alginate solution is 0.5-2.5 g / 100 mL; and the mass percentage concentration of calcium chloride in the calcium chloride solution is 1.5-2.5%. 3) Preparation of gel spheres: Add sodium alginate solution dropwise into calcium chloride solution, stir, and allow to stand to obtain gel spheres. 4) Post-processing: remove the gel balls and wash them to obtain the allelopathic substance slow-release agent; In step 1), the magnolia leaf powder and the barley straw powder are mixed and then extracted with water to obtain an extract; or the magnolia leaf powder is extracted with water to obtain a magnolia leaf extract, and the barley straw powder is extracted with water to obtain a barley straw extract, and the two are mixed to obtain an extract.

2. The method for preparing the allelopathic substance sustained-release agent according to claim 1, wherein: Evaporate and concentrate until the mass volume ratio of plant powder to extract is 1 g:1 mL.

3. The method for preparing the allelopathic substance sustained-release agent according to claim 1, wherein: The mass ratio of magnolia grandiflora leaves to barley straw is 1:

1.

4. The method for preparing the allelopathic substance sustained-release agent according to claim 1, wherein: In step 2), the amount of plant powder added is 1-5 g / 100 mL; the concentration of sodium alginate in the sodium alginate solution is 1.5-2.0 g / 100 mL; and the mass percentage concentration of calcium chloride in the calcium chloride solution is 2%.

5. The allelopathic substance sustained-release agent prepared by the preparation method of the allelopathic substance sustained-release agent according to any one of claims 1 to 4.

6. Use of the allelopathic substance slow-release agent according to claim 5 in an algaecide.

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