Application of emodin in preparation of marine antifouling agent for inhibiting attachment of fouling organisms and coating

Abstract

The invention relates to the technical field of water antifouling agents, in particular to application of emodin in preparation of a marine antifouling agent for inhibiting fouling organism adhesion and a coating. Emodin is a natural product, the chemical name is 1, 3, 8-trihydroxy-6-methylanthraquinone, and emodin widely exists in living bodies in nature. Experiments and sea area hanging plate detection show that the emodin can inhibit the attachment of large marine fouling organisms including barnacle and moss on the surface of marine facilities, shows efficient antifouling activity, is wide in raw material source, low in cost and easy to obtain in quantity, and can be well used for preventing the attachment of the marine fouling organisms.

Description

Technical Field

[0001] This invention relates to the field of antifouling agents for water bodies, specifically to the use of emodin in the preparation of marine antifouling agents that inhibit the attachment of fouling organisms and coatings. Background Technology

[0002] The surfaces of artificial structures in marine environments are chronically affected by fouling organisms, particularly barnacles. Amphibalanus amphitrite ) and bryophytes ( Bugula neritina Species such as [list of species] pose serious threats to structures like ships and aquaculture platforms due to their high reproductive rate and persistent attachment. Traditional control methods generally rely on organotin compounds or cuprous chloride, leading to ecological risks such as biotoxicity accumulation and sediment pollution.

[0003] Emodin is widely distributed in nature, found in various plants such as aloe, rhubarb, Polygonum multiflorum vine, sage, cassia seed, Dianthus superbus, and Polygonum cuspidatum. This compound is effective against anaerobic bacteria ( anaerobic bacteria It has a strong inhibitory effect and is mainly used in medical, health care, and daily chemical products. However, there are no research reports on the use of emodin as a marine antifouling agent. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide the use of emodin in the preparation of marine antifouling agents that inhibit fouling biofouling and coatings, which can be used as marine antifouling agents.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The first objective of this invention is to provide the use of emodin in the preparation of marine antifouling agents that inhibit fouling bioattachment.

[0006] Emodin, scientifically known as 1,3,8-trihydroxy-6-methylanthraquinone, has the following structural formula: .

[0007] Emodin is widely found in various plants and traditional Chinese medicines, including aloe vera, rhubarb, Polygonum multiflorum vine, sage, cassia seed, Dianthus superbus, and Polygonum cuspidatum. It can be extracted and isolated from these plants. Existing extraction technologies for emodin are mature, the preparation process is simple, the cost is relatively low, and it can be obtained in large quantities, which is conducive to the promotion and application of emodin as a marine antifouling agent. Emodin is a naturally derived compound that is easily degradable; therefore, its use as a marine antifouling agent will not cause long-term impacts or pollution to the marine environment.

[0008] Furthermore, the purpose is to prevent fouling organisms from adhering to the surface of marine artificial facilities. These fouling organisms are selected from at least one of the following: barnacles, bryozoans, sand slugs, sea squirts, oysters, sponges, tube worms, sea lettuce, or mosses. The marine facilities include ships, buoys, marine monitoring instruments, aquaculture facilities, aquaculture platforms, pipelines, or other facilities submerged in the sea. Ships can be vessels, boats, vessels, or dinghies; aquaculture facilities can be nets or cages.

[0009] Furthermore, the fouling organism is selected from at least one of the following: barnacle larvae and multilocular bryozoan larvae.

[0010] Furthermore, the emodin is obtained through plant isolation and extraction.

[0011] When using emodin as a marine antifouling agent, it can be applied in a conventional manner to the surface of marine artificial facilities that need to be protected from fouling organisms, such as by spraying and dipping.

[0012] A second objective of this invention is to provide a marine antifouling coating, comprising: (a) A coating base material, said coating base material comprising a film-forming resin and a polar organic solvent; and (b) A marine antifouling agent, wherein the marine antifouling agent is emodin; Preferably, the marine antifouling agent accounts for 1-40% of the weight of the coating base material; Preferably, the marine antifouling agent accounts for 5-30% of the weight of the coating base.

[0013] Emodin is poorly soluble in water but readily soluble in polar organic solvents such as ethanol. It also has good lipophilic properties. By using the above-mentioned coating base material and emodin to prepare marine antifouling coatings, the release rate of emodin can be controlled by the dispersion and protection effect of the coating base material on emodin, thus extending the service life of emodin as a marine antifouling agent.

[0014] To improve the antifouling effect of emodin as a marine antifouling agent, reduce its toxicity, and decrease its dosage, emodin can be used in combination with other marine antifouling agents. Furthermore, the marine antifouling agent includes emodin and at least one of the following compounds, which are selected from dichlorooctylisothiazolinone, tetrachloroisophthalonitrile, zinc pyridinethione, copper pyridinethione, zineb, and bromopyrrolidone.

[0015] Furthermore, the film-forming resin is selected from at least one of zinc acrylate self-polishing resin, copper acrylate self-polishing resin, and silicone acrylate self-polishing resin; And / or, the organic solvent is selected from at least one of xylene, n-butanol and divalent esters.

[0016] Furthermore, the coating base also includes pigments, fillers, and thixotropic agents; Preferably, the pigments and fillers are selected from at least one of titanium dioxide, talc, zinc oxide, and barium sulfate; Preferably, the thixotropic agent is selected from at least one of organobentonite and polyamide wax.

[0017] Furthermore, the coating base material comprises the following components in parts by weight: 20-50 parts film-forming resin, 30-50 parts pigments and fillers, 1-5 parts thixotropic agent, and 10-40 parts solvent.

[0018] Further, the raw materials include the following parts by weight: 25 parts zinc acrylate self-polishing resin, 13 parts zinc oxide, 14 parts talc, 8 parts titanium dioxide, 5 parts barium sulfate, 15 parts emodin, 2 parts polyamide wax, 15 parts xylene, and 3 parts divalent ester.

[0019] Compared with the prior art, the beneficial effects of the present invention are: emodin has a strong inhibitory effect on the attachment of typical marine fouling organisms barnacles and bryozoans larvae, and has a strong effect on the EC50 of barnacle larvae. 50 The value was 3.706 mg / L, and the EC50 value for bryophyte larvae was [missing value]. 50 The concentration was 4.15 mg / L. Because this compound is naturally derived, readily degradable, and environmentally friendly, it is an ideal alternative to traditional heavy metal antifouling agents. Furthermore, emodin is poorly soluble in water and has good lipophilic properties, making it easy to control its release rate and prolong its antifouling effect in oil-based antifouling coating systems. In addition, emodin is readily available and inexpensive, suitable for large-scale preparation, and has a significant economic advantage compared to other natural antifouling agents. Therefore, it can be used alone or in combination with other environmentally friendly antifouling agents to prepare environmentally friendly marine antifouling coatings, which is beneficial to the protection of the marine environment. Antifouling efficacy verification in marine areas showed that the emodin-containing antifouling coating, after 3 months of shallow sea immersion, exhibited superior antifouling performance compared to the control group, demonstrating its application potential. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 The test results show that emodin inhibits the attachment of barnacle larvae (*P<0.05).

[0022] Figure 2 The test results show that emodin inhibits the attachment of bryophyte larvae (*P<0.05).

[0023] Figure 3 The results verify the antifouling efficacy of antifouling coatings containing emodin in marine areas. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise specified, all methods described herein are conventional methods, and all raw materials described herein are available from publicly available commercial sources.

[0026] Example 1: Experiment on the inhibition of barnacle larvae attachment by emodin in typical foul-smelling bio-patterns. Stones with adult barnacles attached were brought back to the laboratory from the intertidal zone, cleaned, and then placed in clean natural seawater to induce spawning. Nauplius larvae of the barnacles were collected using a single light source and isochoric algae (Gynostemma pentaphyllum). Isochrysis galbana As bait, the larvae are cultured at room temperature for 4-5 days and then metamorphose into golden star larvae. The golden star larvae are collected and stored in a 4°C refrigerator for testing.

[0027] Emodin was dissolved in DMSO and prepared into test solutions of different concentrations (1, 3, 5, 10 μg / mL) with sterilized seawater. Sterile seawater containing an equal volume of DMSO was set up as a control group. Three parallel groups were set up for each concentration.

[0028] Add 5 mL of the above test solution to a 6-well plate, and then add 20–30 barnacle larvae to each well. Incubate at room temperature for 72 h, then observe and record the number of attached larvae in each experimental group under a microscope, and calculate the attachment rate. Use GraphPad software to determine the half-maximal inhibitory concentration (EC50) of emodin on the attachment of barnacle larvae to barnacle larvae. 50 SPSS 27.0 was used to calculate the significant differences between the experimental and control groups. The test results of emodin inhibiting the attachment of barnacle larvae are shown in the attached figure. Figure 1 As shown.

[0029] Experimental results showed that emodin could effectively inhibit the attachment of barnacle larvae with typical fouling biomarkers, with a half-maximum inhibitory concentration (EC50) of [missing value]. 50 It was 3.706 mg / L.

[0030] Example 2: Experiment on the inhibition of attachment of bryozoa larvae, a typical fouling organism, by emodin Adult multilocular bryozoans were collected from a marine artificial facility, placed in seawater, aerated, and brought back to the laboratory. They were then cultured overnight at room temperature. The aeration source was then turned off, and the larvae released by the bryozoans were collected using a single light source. The collected larvae were immediately subjected to testing experiments.

[0031] Emodin was dissolved in DMSO and prepared into test solutions of different concentrations (0.1, 0.5, 1, 2, 5 μg / mL) with sterilized seawater. Sterile seawater containing an equal volume of DMSO was set up as a control group. Three parallel groups were set up for each concentration.

[0032] Add 5 mL of the above test solution to a 6-well plate, then add approximately 20-30 bryophyte larvae. During the initial testing phase, drop the floating larvae from each well into the water every hour to prevent them from being unable to submerge due to surface tension, which could affect the test results. After culturing in the dark at room temperature for 24 hours, observe and record the number of attached bryophyte larvae in each well using a microscope, and calculate the attachment rate. Use GraphPad software to determine the half-maximal inhibitory concentration (CMC) of emodin for bryophyte larval attachment. 50 SPSS 27.0 was used to calculate the significant differences between the experimental and control groups. The test results of emodin inhibiting the attachment of bryophyte larvae are shown in the attached figure. Figure 2 As shown.

[0033] Experimental results showed that emodin can effectively inhibit the attachment of larvae of the typical fouling organism, Bryophyte multilocularis, with a half-maximal inhibitory concentration (EC50) of [missing value]. 50 The concentration was 4.15 mg / L.

[0034] Example 3: Verification of antifouling effectiveness in marine areas Emodin was prepared into a marine antifouling coating according to the following formula, and its antifouling efficacy in marine areas was verified: The marine antifouling coating includes a coating base and emodin as the marine antifouling agent, and its formula is as follows: (1) 25 parts by weight of zinc acrylate self-polishing resin (2) 13 parts by weight of zinc oxide (3) 14 parts by weight of talc (4) 8 parts by weight of titanium dioxide (5) 5 parts by weight of barium sulfate (6) 15 parts by weight of emodin (7) 2 parts by weight of polyamide wax (8) 15 parts by weight of xylene (9) 3 parts by weight of divalent ester The specific manufacturing steps for the above-mentioned marine antifouling coating are as follows: Add xylene and divalent ester to a grinding jar in proportion, and add polyamide wax under low speed stirring in a high-speed disperser until uniform. Then slowly add zinc acrylate self-polishing resin and continue to disperse uniformly at low speed. Increase the disperser speed and gradually add zinc oxide, talc, titanium dioxide, barium sulfate and emodin antifouling agent. After high-speed dispersion, add 20% of the formula weight of glass beads, grind at high speed for 1 hour, and then filter through a 100-mesh sieve to obtain a marine antifouling coating containing emodin.

[0035] The specific methods for verifying the antifouling effectiveness of the above-mentioned antifouling coatings in marine areas are as follows: The aforementioned marine antifouling coating was sprayed onto an epoxy resin board (200mm × 100mm), with a dry film thickness controlled at approximately 200μm. Testing showed that the antifouling coating exhibited Grade 1 adhesion on the epoxy resin board, indicating good application results and a uniform film. A blank control group and a negative control group were established. The blank control group used epoxy resin boards without antifouling coating, while the negative control group used epoxy resin boards coated with a base material free of emodin. The samples were suspended on a shallow-sea floating raft at a depth of approximately 1.5m. Monthly, the samples were retrieved from the sea to inspect for biofouling and photographed. The photographs were then analyzed to calculate the biofouling coverage rate, which was compared with the control group to analyze the antifouling efficacy of the marine antifouling coating.

[0036] The results of the marine pollution prevention effectiveness verification are attached. Figure 3 As shown, the results indicate that after 3 months of application in the sea, the surface coverage of large fouling organisms in the antifouling coating containing emodin was 0%, which was significantly lower than the 100% coverage in the blank control group and the negative control group, indicating that emodin has excellent antifouling efficacy in the sea.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit them; although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this application or equivalent substitutions can be made to some technical features, all of which should be covered within the scope of the technical solutions claimed in this application.

Claims

1. The use of emodin in the preparation of marine antifouling agents that inhibit fouling biofouling.

2. The use according to claim 1, characterized in that, The fouling organisms are selected from at least one of barnacles, bryozoans, sand sieves, sea squirts, oysters, sponges, tube worms, sea lettuce, or mosses.

3. The use according to claim 1, characterized in that, The fouling organisms are selected from at least one of the following: barnacle larvae and multilocular bryozoan larvae.

4. The use according to claim 1, characterized in that, The emodin was obtained through plant isolation and extraction.

5. A marine antifouling coating, characterized in that, include: (a) A coating base material, said coating base material comprising a film-forming resin and a polar organic solvent; as well as (b) A marine antifouling agent, wherein the marine antifouling agent is emodin; Preferably, the marine antifouling agent accounts for 1-40% of the weight of the coating base material; Preferably, the marine antifouling agent accounts for 5-30% of the weight of the coating base.

6. The marine antifouling coating according to claim 5, characterized in that, The marine antifouling agent includes emodin and at least one of the following compounds selected from dichlorooctylisothiazolinone, tetrachloroisophthalonitrile, zinc pyridinethione, copper pyridinethione, zineb, and bromopyrrolidinone.

7. A marine antifouling coating according to claim 5 or 6, characterized in that, The film-forming resin is selected from at least one of zinc acrylate self-polishing resin, copper acrylate self-polishing resin and silicone acrylate self-polishing resin; And / or, the organic solvent is selected from at least one of xylene, n-butanol and divalent esters.

8. A marine antifouling coating according to claim 5, characterized in that, Coating base materials also include pigments, fillers, and thixotropic agents; Preferably, the pigments and fillers are selected from at least one of titanium dioxide, talc, zinc oxide, and barium sulfate; Preferably, the thixotropic agent is selected from at least one of organobentonite and polyamide wax.

9. A marine antifouling coating according to claim 5 or 6, characterized in that, The coating base material comprises the following components in parts by weight: 20-50 parts film-forming resin, 30-50 parts pigments and fillers, 1-5 parts thixotropic agent, and 10-40 parts solvent.

10. The marine antifouling coating according to claim 5, characterized in that, The raw materials include the following parts by weight: 25 parts zinc acrylate self-polishing resin, 13 parts zinc oxide, 14 parts talc, 8 parts titanium dioxide, 5 parts barium sulfate, 15 parts emodin, 2 parts polyamide wax, 15 parts xylene, and 3 parts divalent ester.

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