Preparation method of photocatalytic marine antifouling paint

Abstract

The invention belongs to the technical field of coatings, and discloses a preparation method of a photocatalytic marine antifouling coating, which comprises the following steps: mixing urea, ferric oxide and water, uniformly stirring, drying and calcining; mixing the obtained oxide drug with aniline, sodium dodecyl benzene sulfonate and water, and uniformly stirring; and adding an ammonium persulfate aqueous solution, alternately washing the material with water and absolute ethyl alcohol by virtue of refrigeration, freeze-drying to obtain a brown solid, grinding into powder, and finally uniformly mixing the obtained catalyst powder with a conventional hull paint coating in proportion to obtain a final product. The photocatalytic marine antifouling paint provided by the invention utilizes the catalytic oxidation capacity of active free radicals in a photocatalytic material. Electrons are excited through illumination to form electron-hole pairs, and further react with water and oxygen on the surface of the material to generate active oxygen species such as hydroxyl free radicals and the like. As the active oxygen species have strong oxidizing property, marine microorganisms can be effectively prevented from being attached and causing fouling.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and particularly relates to a preparation method of a novel photocatalytic marine antifouling coating. Background Art

[0002] In the shipping industry, the fouling of marine organisms is a severe problem. The attachment of marine organisms increases the weight of the hull, thereby increasing the navigation resistance and reducing the fuel efficiency. Investigations show that marine organism fouling significantly increases the fuel consumption of the global shipping industry, and thus sharply increases the navigation cost. In addition, the fouling of marine organisms also causes corrosion problems and shortens the service life of ships.

[0003] Currently, the commonly used antifouling coatings include five types: traditional type, leaching type, ablative type, self-polishing type, and self-leaching type. The early used traditional antifouling coatings usually added toxic substances such as copper and mercury oxides, and organotin in rosin as antifouling agents, and utilized the release of toxic substances by the rosin binder when encountering water. The antifouling period of such coatings is relatively short, generally only about one year. The leaching type antifouling coatings use cuprous oxide as the antifouling agent and chlorinated rubber or ethylene as the binder, and some merchants also add pesticides. The thickness of its coating increases with the polishing time, which may affect the effective release of the antifouling agent. The ablative type and tin-free self-polishing type antifouling coatings also use cuprous oxide as the antifouling agent and doping pesticides to enhance the effect, but do not form a sandwich system, thus affecting the effective penetration of the antifouling agent. The self-leaching type coatings have no biological toxicity and rely on low surface energy to achieve antifouling effect, but are only applicable to high-speed driving, and have low bonding strength and short service life.

[0004] Heavy metal antifouling agents such as tin, mercury, and copper have great ecological toxicity, and their large-scale use has led to serious environmental pollution in coastal waters. The early used tributyltin was considered to be one of the most toxic chemicals in the marine environment, which could cause deformities and gender changes in mollusks. Only microgram-level tributyltin could interfere with the calcium metabolism of oysters and cause sexual distortion of Nassarius, and even higher concentrations could cause permanent deformities in marine crustaceans. By monitoring the butyltin pollution in the coastal waters of the Bohai Sea through biological indicators such as mussels and oysters, it was found that the butyltin pollution concentration in the Dalian area seriously exceeded the standard. After 2008, antifouling coatings containing organotin were prohibited from being used. Similarly, the copper ions in the cuprous oxide antifouling coatings are continuously released and accumulate in the marine environment and organisms, especially in coastal areas, resulting in biological mutations and causing pollution of seafood. These copper ions flow into the food chain and may pose a hazard to human health.

[0005] At present, Chinese invention patent CN114106610A discloses a nano-photocatalytic marine antifouling and anticorrosion coating. The antifouling and antibacterial effects of this invention are good, but due to problems such as the easy photocorrosion of titanium dioxide and the easy agglomeration of nanoparticles caused by only ball milling and dispersing the materials, the long-term effectiveness and stability need to be improved.

[0006] Therefore, it is necessary to develop a new type of photocatalyst antifouling coating. Summary of the Invention

[0007] Based on the problems existing in the background technology, the present invention proposes a brand-new photocatalytic marine antifouling coating. The photocatalytic marine antifouling coating of the present invention utilizes the catalytic oxidation ability of active free radicals in the photocatalytic material. By irradiating light to excite electrons to form electron-hole pairs, and further reacting with water and oxygen on the surface of the material, reactive oxygen species such as hydroxyl radicals are generated. Due to the strong oxidizing property of these reactive oxygen species, it can effectively prevent the attachment of marine microorganisms and cause fouling. In addition, compared with ordinary titanium oxide as a photocatalyst, the doping of carbon elements into iron oxide in the present invention is very helpful for improving the overall stability of the material, adjusting the energy band structure of the material, promoting the separation and transmission of charges, thereby greatly enhancing the light absorption and catalytic activity of the material; introducing polyaniline to modify the surface, the nanoparticles have good dispersibility, increasing the specific surface area of the photocatalytic reaction, and further improving its antifouling performance.

[0008] The technical solution of the present invention:

[0009] A preparation method of a photocatalytic marine antifouling coating, comprising the following steps:

[0010] Step 1: Mix urea and iron oxide in proportion and dissolve them in deionized water, magnetically stir at room temperature for more than 6 hours to ensure uniform mixing, and then dry at a constant temperature for more than 24 hours;

[0011] Preferably: The particle size of iron oxide is 200-300 nm, the mass ratio of urea to iron oxide is 2:5, the concentration of urea is 0.2 g / ml respectively, and after the temperature rises to 70-80 °C, dry at a constant temperature.

[0012] Step 2: Grind the dried mixture into powder, transfer it to a crucible, put it into a muffle furnace, and calcine at a constant temperature for 5 hours to obtain oxide drug powder;

[0013] Preferably: The muffle furnace is heated to 350-400 °C, and the heating rate is 5 °C / min.

[0014] Step 3: Mix aniline, sodium dodecylbenzenesulfonate (SDBS) and the oxide drug powder obtained in Step 2 in proportion, dissolve them in ultrapure water, and magnetically stir at room temperature for 0.5-1.0 hour; then add an aqueous solution of ammonium persulfate, stir to mix well, and then refrigerate the mixture for more than 24 hours;

[0015] Preferably, the ratio of aniline, sodium dodecylbenzenesulfonate, and the oxide drug powder is 0.40 ml: 0.39 g: 1 g, and the concentration of aniline is controlled to be 0.02 ml / ml; the concentration of the ammonium persulfate aqueous solution is 0.2 g / ml, the volume ratio of the ammonium persulfate aqueous solution to ultrapure water is 1:4, and the refrigeration temperature is 0 °C.

[0016] Step 4: Wash the material alternately with ultrapure water and absolute ethanol, collect it and put it into a centrifuge tube, seal it with tape and punch holes, and freeze it into ice in the lower layer of the refrigerator;

[0017] Step 5: Put the frozen material into a vacuum freeze dryer, and dry it for more than 24 hours under the conditions of -60 to -70 °C and a pressure below 100 Pa to obtain a brown solid, and finally grind it into powder;

[0018] Step 6: Mix the hull paint coating and the prepared material powder in proportion, stir well, and complete the preparation.

[0019] Preferably, the mixing mass ratio of the material powder is 5-10%.

[0020] Advantages of the present invention:

[0021] 1) As an efficient environmental governance means, the core mechanism of photocatalysis technology is to generate highly active free radicals through photosensitive materials under light irradiation to achieve the catalytic oxidation and decomposition of pollutants. When semiconductor nanoparticles absorb the photon energy of a specific wavelength, the valence band electrons are excited and jump to the conduction band, forming electron-hole pairs with redox ability. These photo-generated carriers interact with water molecules and dissolved oxygen through interfacial reactions and can be converted into highly active oxygen species such as hydroxyl radicals (·OH) and superoxide radicals (·O2 - ) etc. Their strong oxidation characteristics can not only degrade organic pollutants, but also inhibit the attachment and reproduction of marine organisms (such as barnacles and mussels) on the ship surface by destroying the cell membrane structure of microorganisms, providing a green solution for hull antifouling;

[0022] 2) Integrating photocatalytic materials into the marine antifouling coating system significantly reduces the negative effects of traditional coatings on the marine ecosystem. Compared with traditional antifouling coatings containing toxic components such as organotin compounds or cuprous oxide, the photocatalytic coating achieves antifouling functions through physical-chemical synergistic effects, avoiding the release and accumulation of persistent toxic substances in the marine environment. This environmentally friendly alternative not only reduces the risk of bioaccumulation of harmful substances in the marine food chain, but also reduces the ship maintenance cost and the economic pressure of marine ecological restoration, showing important value in protecting marine biodiversity, maintaining human health and safety, and promoting the sustainable development of the blue economy;

[0023] 3) This product uses polyaniline-modified iron oxide particles. By utilizing the synergistic effect between the two, it comprehensively optimizes aspects such as light absorption, charge transport, and surface reaction kinetics. Not only does it broaden the light response range of the material to the visible light region, but polyaniline can also act as an electron acceptor to rapidly transfer the photo-generated electrons in the conduction band of iron oxide, effectively inhibiting charge recombination. Meanwhile, the holes remain in the valence band of iron oxide to participate in the activation of H2O2 to generate hydroxyl radicals (·OH). In addition, the amino functional groups of polyaniline can anchor iron oxide nanoparticles to prevent aggregation, increase the specific surface area of the catalyst and the exposed Fe-O active sites, and greatly improve the antifouling and antibacterial properties of the product. Description of the Drawings

[0024] Figure 1 is the photocatalytic degradation effect of the obtained sample on pollutants. Detailed Embodiments

[0025] The following further describes the detailed embodiments of the present invention in combination with the drawings and technical solutions.

[0026] Example 1:

[0027] A preparation method of a photocatalytic marine antifouling coating includes the following steps:

[0028] Step 1: Mix urea and iron oxide with a particle size of 200 - 300 nm in a ratio of 2 g : 5 g and dissolve them in 10 ml of deionized water. Stir magnetically at room temperature for more than 6 hours to ensure uniform mixing, and then dry at a constant temperature of 70°C for more than 24 hours.

[0029] Step 2: Grind the dried mixture into powder, transfer it to a crucible, place it in a muffle furnace, with a heating rate of 5°C / min, and calcine at a constant temperature of 350°C for 5 hours to obtain iron oxide pharmaceutical powder.

[0030] Step 3: According to the ratio (4 g of iron oxide, 0.4 g of polyaniline, 0.39 g of SDBS, and 20 ml of deionized water, with the ratio of iron oxide to polyaniline being 10 : 1), mix and stir at room temperature for 0.5 hours, and then perform ultrasonic treatment for 0.5 hours. After ultrasonic treatment, continue to cool for 0.5 hours to obtain a uniform suspension.

[0031] Step 4: Prepare an ammonium persulfate solution (ammonium persulfate : ultrapure water = 1 : 5), add 5 ml of this solution to the suspension in Step 1, stir for 1 minute, mix evenly, and refrigerate for more than 24 hours.

[0032] Step 5: Wash alternately with ultrapure water and absolute ethanol, then centrifuge and freeze, and finally freeze-dry at -60°C for 24 hours.

[0033] Example 2

[0034] Replace the amount of iron oxide with 2 g (the ratio of iron oxide to polyaniline is 5:1), and the other implementation steps are the same as those in Example 1. Compare the photocatalytic degradation effect of the product of the present invention on pollutants;

[0035] Example 3

[0036] Replace the amount of iron oxide with 1 g (the ratio of iron oxide to polyaniline is 5:2), and the other implementation steps are the same as those in Example 1. Compare the photocatalytic degradation effect of the product of the present invention on pollutants;

[0037] Example 4

[0038] Replace the amount of iron oxide with 0.5 g (the ratio of iron oxide to polyaniline is 5:4), and the other implementation steps are the same as those in Example 1. Compare the photocatalytic degradation effect of the product of the present invention on pollutants;

[0039] Example 5

[0040] A preparation method of a photocatalytic marine antifouling coating includes the following steps:

[0041] Step 1: Mix urea and iron oxide with a particle size of 200 - 300 nm in a ratio of 2 g:5 g and dissolve them in 10 ml of deionized water. Stir magnetically at room temperature for more than 6 hours to ensure uniform mixing, and then dry at a constant temperature of 70 °C for more than 24 hours.

[0042] Step 2: Grind the dried mixture into powder, transfer it to a crucible, place it in a muffle furnace, and heat it at a rate of 5 °C / min. Calcinate at a constant temperature of 350 °C for 5 hours to obtain iron oxide pharmaceutical powder.

[0043] Compared with the first four examples, the iron oxide powder was not modified with polyaniline (the ratio of iron oxide to polyaniline is 1:0)

[0044] Example 6

[0045] Select the samples obtained in Examples 1, 2, 3, 4, and 5 of the present invention for testing, and test their photocatalytic degradation performance of pollutants. Prepare a pollutant solution, construct a photocatalytic reaction system (50 ml of ultrapure water + 20 mg of the sample obtained in the example + 1 ml of the pollutant solution, ultrasonically treat for 20 - 30 min until uniformly dispersed), and measure the absorbance of the solution every 10 min under the condition of a wavelength of 554 mm. The test results for 60 min are as Figure 1 shown.

[0046] It can be seen from Figure 1 that the sample obtained in Example 3 has the best photocatalytic degradation effect on pollutants. It shows that the introduction of an appropriate proportion of aniline not only broadens the light absorption range of the material, making it have a higher photon utilization rate in the visible light region, but also promotes Fe 2+ / Fe 3+Recycling and stably generating reactive oxygen species, significantly enhancing the pollutant degradation ability.

[0047] Example 7

[0048] The Example 3 of the present invention was selected for experiments with a blank control group to test its antifouling and antibacterial properties. LB liquid medium was configured to culture Escherichia coli, and the bacterial solution was respectively dropped onto a plate with a paint coating containing 10% of the catalyst sample of Example 3 at the bottom and a blank plate, and cultured under light conditions for 48 h, and the Escherichia coli colony count was performed every 24 h. It was calculated that at 24 h, the removal rate of Escherichia coli was 99.804%; at 48 h, the removal rate of Escherichia coli was 99.939%.

Claims

1. A method for preparing a photocatalytic marine antifouling coating, characterized in that: The following steps are involved: Step 1: Mix urea and iron oxide in proportion and dissolve in deionized water, stir magnetically for more than 6 hours at room temperature to ensure uniform mixing, and then dry at a constant temperature for more than 24 hours; Step 2: Grind the dried mixture into powder, transfer it into a crucible, put it into a muffle furnace, and calcine it at a constant temperature for 5 hours to obtain oxide drug powder; Step 3: Mix aniline, sodium dodecylbenzene sulfonate and the oxide drug powder obtained in step 2 according to a certain proportion, dissolve in ultrapure water, and stir magnetically for 0.5-1.0 hour at room temperature; then add an aqueous solution of ammonium persulfate, stir to mix thoroughly, and then refrigerate the mixture for more than 24 hours; Step 4: Wash the material alternately with ultrapure water and anhydrous ethanol, collect and place it in a centrifuge tube, seal it with tape and pierce it, and freeze it in the bottom layer of the refrigerator; Step 5: Place the frozen material into a vacuum freeze dryer and dry it for more than 24 hours at -60 to -70°C and a pressure below 100 Pa to obtain a brown solid, which is then ground into powder; Step 6: Mix the hull paint and the prepared material powder in proportion, stir well, and complete the preparation.

2. The preparation method according to claim 1, characterized in that: In step 1, the particle size of iron oxide is 200-300 nm, the mass ratio of urea to iron oxide is 2:5, and the concentration of urea is 0.2 g / ml.

3. The preparation method according to claim 1, characterized in that: In step 1, the temperature of the constant temperature condition is 70-80°C.

4. The preparation method according to claim 1, characterized in that: In step 2, the temperature of the muffle furnace is raised to 350-400°C at a heating rate of 5°C / min.

5. The preparation method according to claim 1, characterized in that: In step 3, the ratio of aniline, sodium dodecylbenzene sulfonate and oxide drug powder is 0.40ml:0.39g:1g, and the concentration of aniline is controlled to be 0.02ml / ml.

6. The preparation method according to claim 1, characterized in that: In step 3, the concentration of the ammonium persulfate aqueous solution is 0.2 g / ml, and the volume ratio of the ammonium persulfate aqueous solution to ultrapure water is 1:

4.

7. The preparation method according to claim 1, characterized in that: In step 3, the refrigeration temperature is 0°C.

8. The preparation method according to claim 1, characterized in that: In step six, the mixing mass ratio of the material powder is 5-10%.

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