Allelochemical sustained-release agent as well as preparation method and application thereof

Abstract

The invention relates to an allelochemical slow-release agent as well as a preparation method and application thereof, and belongs to the technical field of water environment treatment. The technical problem to be solved by the invention is to provide the preparation method of the allelochemical slow-release agent with good slow-release and algae-inhibiting effects. The method comprises the following steps: adding water into southern magnolia leaves and barley straw powder, and extracting to obtain a leaching solution; adding sodium alginate, southern magnolia leaves and barley straw powder into the leach liquor, and stirring until the sodium alginate is completely dissolved to obtain a sodium alginate solution; dropwise adding the sodium alginate solution into the calcium chloride solution, stirring, and standing after dropwise adding to obtain gel balls; and taking out and washing to obtain the allelochemical slow-release agent. The allelochemical slow-release agent can continuously release the allelochemical in a low dosage for algal inhibition, the dosage is low, the algal inhibition effect and the slow-release effect can be achieved only by adding 50-100 g of the allelochemical slow-release agent into one ton of water, the good inhibition effect can be achieved 21 days after the allelochemical slow-release agent is added, and the allelochemical slow-release agent can be used as a slow-release algaecide and can be widely applied to actual rivers and lakes.

Description

Technical Field

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

[0002] In recent years, the outbreak of cyanobacteria caused by eutrophication has brought many problems. When cyanobacteria blooms occur, the water environment will deteriorate, causing the death of other aquatic organisms and further deteriorating the environment. At present, cyanobacteria bloom control technology can be divided into physical algae control technology, chemical algae control technology and biological algae control technology. Among them, chemical algae control technology is mainly used for emergency treatment when cyanobacteria blooms occur. It mainly uses chemical algaecides to disinfect cyanobacteria. However, most chemical algaecides are easy to cause secondary pollution to the water body during the actual release process.

[0003] Allelopathy refers to the mutual induction between plants through signal compounds, which is widely present in plant community systems. The allelopathic substances involved in the formation of allelopathic effects are secondary metabolites in the process of plant growth. They can generally be degraded under natural conditions and will not accumulate in the ecosystem, so they have good ecological safety. At present, many allelopathic substances produced by aquatic plants have been proven to have a certain effect of inhibiting the growth of algae. However, when the water body has been severely eutrophicated or algae have already erupted, it is difficult for aquatic plants to survive in it. Therefore, it is relatively difficult to deal with algal turbidity water bodies relying solely on the allelopathic substances released by aquatic plants.

[0004] In addition to aquatic plants, terrestrial plants also have allelopathic substances, and terrestrial plants have large biomass and rich allelopathic substances. At present, allelopathic substances of many terrestrial plants have been reported to have algae inhibition effects. However, the content of allelopathic substances in plant materials is very small. If plant materials are directly added to water bodies, it will greatly affect the beauty of the water body. Therefore, the release of slow-release agents containing allelopathic substances can greatly reduce the impact on the beauty of the water body, and at the same time, it can also greatly reduce the amount of release.

[0005] Patent CN106614556A discloses a method for preparing and using a slow-release algaecide, which combines phenolic acid substances with encapsulation technology, selects degradable materials, and adjusts the pH value of the required materials for encapsulation, while maintaining the allelopathic activity of the core embedded material, and inhibits algae in the water by slowly releasing allelopathic substances. However, this method is complex and costly, and the inhibitory effect of the prepared product 0.2 g of slow-release agent added to 50 mL of water with a low algae concentration is only 70%. The amount of product added is very large, and the algae inhibition effect is not good, so it cannot be expanded to actual rivers and lakes, and it needs to be repeatedly added with the slow-release agent 3-4 days after it is added, and the slow-release effect is not good. 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: 1) Extraction: extracting plant powder with water, evaporating and concentrating 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 0.5-2.0:1; 2) Prepare the solution: add sodium alginate and plant powder to the extract, 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; 3) Preparation of gel spheres: drop the sodium alginate solution into the calcium chloride solution drop by drop, stir, and let stand after the addition is completed to obtain gel spheres; 4) Post-processing: Take out the gel balls, wash them, and obtain the allelopathic substance sustained-release agent.

[0008] In one embodiment of the present invention, the evaporation concentration is performed until the mass volume ratio of the powder to the extract is 0.2-1.2 g: 1 mL.

[0009] In a specific embodiment of the present invention, the evaporation concentration is performed until the mass volume ratio of the plant powder to the extract is 1 g: 1 mL.

[0010] 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.

[0011] In one embodiment of the present invention, the mass ratio of Magnolia grandiflora leaves to barley straw is 1:1.

[0012] In one embodiment of the present invention, in step 2), the amount of plant powder added is 1-10 g / 100 mL; in the sodium alginate solution, the concentration of sodium alginate is 0.5-2.5 g / 100 mL; in the calcium chloride solution, the mass percentage concentration of calcium chloride is 1.5-2.5%.

[0013] 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; in the sodium alginate solution, the concentration of sodium alginate is 1.5-2.0 g / 100 mL; in the calcium chloride solution, the mass percentage concentration of calcium chloride is 2%.

[0014] The second technical problem solved by the present invention is to provide a sustained-release agent for allelopathic substances.

[0015] The allelopathic substance slow-release agent of the present invention is prepared by the 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.

[0016] The present invention also provides application of the allelopathic substance slow-release agent of the present invention in an algaecide.

[0017] 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 can be added once to achieve a continuous algae inhibition effect.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The allelopathic substance sustained-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 to be added in one ton of water to achieve the algae inhibition effect. The sustained-release effect is good, and a good inhibitory effect can be achieved 21 days after the addition. The agent can be used as a sustained-release algaecide and expanded to be applied in actual rivers and lakes.

[0019] The preparation method of the allelopathic substance sustained-release agent of the present invention has simple process and low cost, is suitable for industrial mass production, and reduces the production cost of the sustained-release agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a graph showing the daily chlorophyll content changes in each experimental group in Test Example 1 of the present invention.

[0021] 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, wherein 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.

[0022] Figure 3 This is a graph showing the daily chlorophyll content changes in each experimental group in Test Example 2 of the present invention. DETAILED DESCRIPTION

[0023] The preparation method of the allelopathic substance sustained-release agent of the present invention comprises the following steps: 1) Extraction: extracting plant powder with water, evaporating and concentrating 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 0.5-2.0:1; 2) Prepare the solution: add sodium alginate and plant powder to the extract, 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; 3) Preparation of gel spheres: drop the sodium alginate solution into the calcium chloride solution drop by drop, stir, and let stand after the addition is completed to obtain gel spheres; 4) Post-processing: Take out the gel balls, wash them, and obtain the allelopathic substance sustained-release agent.

[0024] The method of the invention is simple, does not require special equipment, has low cost, and 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.

[0025] In one embodiment of the present invention, the evaporation concentration is performed until the mass volume ratio of the powder to the extract is 0.2-1.2 g: 1 mL.

[0026] In a specific embodiment of the present invention, the evaporation concentration is performed until the mass volume ratio of the plant powder to the extract is 1 g: 1 mL.

[0027] 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.

[0028] In one embodiment of the present invention, the mass ratio of Magnolia grandiflora leaves to barley straw is 1:1.

[0029] In one embodiment of the present invention, in step 2), the amount of plant powder added is 1-10 g / 100 mL; in the sodium alginate solution, the concentration of sodium alginate is 0.5-2.5 g / 100 mL; in the calcium chloride solution, the mass percentage concentration of calcium chloride is 1.5-2.5%.

[0030] 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; in the sodium alginate solution, the concentration of sodium alginate is 1.5-2.0 g / 100 mL; in the calcium chloride solution, the mass percentage concentration of calcium chloride is 2%.

[0031] The allelopathic substance slow-release agent of the present invention is prepared by the 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.

[0032] 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 can be added once to achieve a continuous algae inhibition effect.

[0033] The specific implementation modes of the present invention are further described below in conjunction with embodiments, but the present invention is not limited to the scope of the embodiments.

[0034] Example 1 The allelopathic substance sustained-release agent was prepared according to the following method: (1) Pretreatment of Magnolia grandiflora and barley straw The collected Magnolia grandiflora leaves and barley straw were washed and dried in an oven at 55°C. The two plants were crushed as much as possible and then put into a grinder and crushed respectively. The powders of the two plants were sieved through a 120-mesh sieve to obtain the powders of the plants.

[0035] (2) Extraction of Magnolia grandiflora and barley straw 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 mother liquor of the two plants.

[0036] (3) Preparation of allelopathic sustained-release agents 50 mL of each of the two plant extract mother liquors 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 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 the gel balls were washed with 200 mL of water to obtain the final allelopathic substance sustained-release agent.

[0037] Comparative Example 1 The allelopathic substance sustained-release agent was prepared according to the following method: (1) Magnolia grandiflora pretreatment The collected fallen leaves of Magnolia grandiflora were washed and dried in an oven at 55°C. The plants were crushed as much as possible and then put into a grinder for grinding. The leaves were sieved through a 120-mesh sieve to obtain Magnolia grandiflora powder.

[0038] (2) Magnolia grandiflora extraction Weigh 100 g of Magnolia grandiflora powder, add 1 L of pure water and soak for 48 h, filter, evaporate and concentrate the filtrate to 100 mL to obtain the Magnolia grandiflora extraction mother liquor.

[0039] (3) Preparation of allelopathic sustained-release agents Take 100 mL of Magnolia grandiflora extract mother liquor, add 1.5 g of sodium alginate and 4 g of Magnolia grandiflora powder, stir until the sodium alginate is completely dissolved, add it drop by drop into a 2% calcium chloride solution to complex the sodium alginate into gel balls, let it stand for 10 min, filter, and wash the gel balls with 200 mL of water to obtain the final allelopathic substance sustained-release agent.

[0040] Comparative Example 2 The allelopathic substance sustained-release agent was prepared according to the following method: (1) Barley straw pretreatment The collected barley straw was 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 barley straw powder.

[0041] (2) Barley straw extraction Weigh 100 g of barley straw powder, add 1 L of pure water and soak for 48 h, filter, and evaporate and concentrate the filtrate to 100 mL to obtain the barley straw extraction mother liquor.

[0042] (3) Preparation of allelopathic sustained-release agents 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, add it drop by drop into a 2% calcium chloride solution to complex the sodium alginate into gel balls, let it stand for 10 min, filter, and wash the gel balls with 200 mL of water to obtain the final allelopathic substance sustained-release agent.

[0043] Test Example 1 A total of 15 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 body was Microcystis. The 15 water columns were equally divided into three groups, and different masses of the allelopathic substance slow-release agent in Example 1 were added to each group. 500 mL of water samples were taken out every day, and 500 mL of algae-turbid water was newly added. The changes in chlorophyll content in each group were monitored every day. The results are shown in Tables 1 and Figure 1 , the numerical unit in Table 1 is ppb.

[0044] Table 1 Daily chlorophyll content data of each experimental group From the experimental results, it can be seen that at the beginning of the experiment, the same amount of algae solution was added for cultivation. After two days, the chlorophyll concentration of each group was quite different. However, one week after the slow-release agent was added, the chlorophyll concentration of each experimental group decreased significantly. At the 15th day of the experiment, the chlorophyll content of the experimental group with 0.2 g added began to rise. When the experiment reached the 21st day, the chlorophyll content of each experimental group gradually increased.

[0045] Figure 2 The water color of the three parallel groups on the 29th day of the experiment, from left to right are the control group, 0.2 g group, 0.4 g group, 0.6 g group, and 0.8 g group. From the water color, it can be seen that the colors of the three parallel groups are similar, the experimental repeatability is good, and the color gradually becomes lighter with the increase of the amount of sustained-release agent.

[0046] Test Example 2 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 body was Microcystis. The four water columns were divided into a blank group, a Magnolia grandiflora group, a barley straw group, and a mixed group. Except for the blank group, no slow-release agent was added. 0.6 g of the corresponding allelopathic substance slow-release agent was added to the other groups. Among them, the Magnolia grandiflora 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 Example 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 .

[0047] Table 2 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, evaporating and concentrating 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 0.5-2.0:1; 2) Prepare the solution: add sodium alginate and plant powder to the extract, 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; 3) Preparation of gel spheres: drop the sodium alginate solution into the calcium chloride solution drop by drop, stir, and let stand after the addition is completed to obtain gel spheres; 4) Post-processing: Take out the gel balls, wash them, and obtain the allelopathic substance sustained-release agent.

2. The method for preparing the allelopathic substance sustained-release agent according to claim 1, characterized in that: Evaporate and concentrate until the mass volume ratio of powder to extract is 0.2-1.2 g: 1 mL.

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

4. The method for preparing the allelopathic substance sustained-release agent according to claim 1, characterized in that: In step 1), after mixing the magnolia leaf powder and the barley straw powder, water is added to extract the mixture together 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.

5. The method for preparing the allelopathic substance sustained-release agent according to claim 1, characterized in that: The mass ratio of Magnolia grandiflora leaves to barley straw is 1:

1.

6. The method for preparing the allelopathic substance sustained-release agent according to claim 1, characterized in that: In step 2), the amount of plant powder added is 1-10 g / 100 mL; in the sodium alginate solution, the concentration of sodium alginate is 0.5-2.5 g / 100 mL; in the calcium chloride solution, the mass percentage concentration of calcium chloride is 1.5-2.5%.

7. The method for preparing the allelopathic substance sustained-release agent according to claim 6, characterized in that: In step 2), the amount of plant powder added to the sustained-release agent is 1-5 g / 100 mL; in the sodium alginate solution, the concentration of sodium alginate is 1.5-2.0 g / 100 mL; in the calcium chloride solution, the mass percentage concentration of calcium chloride is 2%.

8. The allelopathic substance sustained-release agent prepared by the method for preparing the allelopathic substance sustained-release agent according to any one of claims 1 to 7.

9. Use of the allelopathic substance slow-release agent according to claim 8 in algaecides.

Images