PH response type slow-release long-acting aquatic product oxygen producer as well as preparation method and application thereof

Abstract

The invention discloses a pH response type slow-release long-acting aquatic product oxygen producer as well as a preparation method and application thereof, and belongs to the technical field of aquaculture and fresh aquatic product transportation. The pH response type slow-release long-acting aquatic product oxygen producer provided by the invention has the effects of intelligent slow release and water quality stabilization. A pH response oxygen release mechanism is created for the first time, the oxygen release speed can be automatically adjusted according to the actual chemical state of a water body, and the crossing from passive release to intelligent control is achieved. The stable oxygen supply can be provided for 24 hours, the fluctuation of the pH value of a water body in the using process can be effectively inhibited, the rising range of the pH value can be controlled within 1.5, and a more stable living environment is created.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture and fresh aquatic product transportation technology, and in particular relates to a pH-responsive slow-release long-acting aquatic oxygenating agent, its preparation method and application. Background Technology

[0002] In aquaculture and live animal transport, dissolved oxygen is a key factor limiting density and survival rates. Chemical oxygenating agents, such as calcium peroxide and sodium percarbonate, are widely used due to their electricity-free operation and rapid onset of action. However, existing technologies have significant drawbacks: First, rapid release and stress: Taking calcium peroxide as an example, it reacts rapidly with water, releasing large amounts of oxygen and calcium hydroxide in a short time, leading to localized supersaturation of dissolved oxygen, a sharp increase in pH (up to 10 or higher), and the generation of reactive oxygen species (ROS) with oxidative stress hazards, causing "emergency" damage to aquatic organisms, which is just as deadly as oxygen deficiency itself. Second, short duration: Conventional powders or tablets lack a slow-release design, with oxygen release concentrated in the first few hours, making it difficult to match the continuous oxygen demand of fish, especially in long-distance transport or high-density aquaculture ponds, requiring frequent application, which is time-consuming and labor-intensive. Third, lack of intelligence: Existing slow-release technologies mostly rely on the slow dissolution of physical barriers, and their oxygen release rate is mainly affected by physical factors such as water temperature and flow, failing to respond to changes in pH, the most important chemical indicator of the water body. When fish are metabolically active and carbon dioxide accumulates, causing the pH to drop, oxygen supply cannot be accelerated; when the pH rises due to the side effects of the oxygenating agent itself, it cannot be slowed down to mitigate the harm.

[0003] Therefore, developing an oxygenating agent that can intelligently regulate oxygen release behavior based on water pH, achieve long-term stable oxygen supply, and minimize pH fluctuations and free radical damage is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a pH-responsive, slow-release, long-acting aquatic oxygenator, its preparation method, and its application. The pH-responsive, slow-release, long-acting aquatic oxygenator provided by this invention achieves a negative correlation between oxygen release rate and water pH (i.e., the lower the pH, the faster the oxygen release; the higher the pH, the slower the oxygen release), thereby ensuring continuous oxygen supply while automatically inhibiting abnormal increases in water pH, maintaining water quality stability, and reducing stress on aquaculture organisms.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a pH-responsive slow-release long-acting aquatic oxygenating agent, comprising an oxygenating core, a smart-responsive coating layer, and an outer coating layer; the smart-responsive coating layer is wrapped around the outside of the oxygenating core; the outer coating layer is wrapped around the outside of the smart-responsive coating layer; The oxygen-enhancing core comprises a primary oxygenator, auxiliary agents, and a slow-release matrix; the auxiliary agents include a pH-controlled release agent and a free radical scavenger; the smart-responsive coating layer comprises cellulose acetate and a pH-sensitive polymer. Further, the smart-responsive coating layer accounts for 10%-30% of the weight of the oxygen-enhancing core.

[0006] Further, by weight, the main oxygenating agent is 50-70 parts, the pH buffer is 10-20 parts, the free radical scavenger is 5-10 parts, and the slow-release matrix is ​​15-25 parts.

[0007] Furthermore, the primary oxygenating agent includes one or more of calcium peroxide, sodium percarbonate, and percarbonamide; and / or, The pH-release agent is selected from calcium dihydrogen phosphate or citric acid; and / or, The free radical scavenger is selected from silicates or urea; and / or, The slow-release matrix is ​​selected from dextrin or soluble starch.

[0008] In this invention, calcium peroxide, sodium percarbonate, or percarbonamide serve as the primary oxygenating agent, providing an oxygen source.

[0009] As pH buffers, calcium dihydrogen phosphate and citric acid can be used to neutralize alkaline substances produced by the hydrolysis of the main oxygenating agent and mitigate the initial pH shock.

[0010] As free radical scavengers / stabilizers, silicates such as food-grade magnesium silicate or urea are used to adsorb or decompose reactive oxygen free radicals (such as ·OH) generated in the early stages of the reaction, thereby reducing oxidative stress.

[0011] As a sustained-release matrix, dextrin or soluble starch acts as a binder and initial sustained-release layer, delaying core disintegration during tableting.

[0012] Furthermore, the pH-sensitive polymer is selected from chitosan, chitosan derivatives, or sodium alginate.

[0013] In this invention, a smart responsive coating layer is wrapped around the oxygen-enhancing core. It is made from a blend of cellulose acetate and a pH-sensitive polymer. This smart responsive coating layer has low solubility and slow swelling in neutral to weakly alkaline water, forming a stable slow-release barrier. When the pH of the outer water layer drops to a set threshold (e.g., below 7.5) due to CO2 accumulation caused by fish respiration and organic matter decomposition, the pH-sensitive polymer chain segments protonate or undergo structural changes, leading to increased swelling and enlarged micropores in the coating layer. This allows water to penetrate the core more easily, thus moderately accelerating the oxygen release rate to meet higher oxygen demands. Conversely, when the pH of the water increases (e.g., above 8.5) due to the side effects of oxygenating agents or algal photosynthesis, the coating layer contracts and becomes more compact, inhibiting water penetration, automatically slowing oxygen release, and preventing further pH spikes, thus forming a negative feedback regulation.

[0014] Secondly, the present invention provides a method for preparing the aforementioned pH-responsive slow-release long-acting aquatic oxygenating agent, comprising the following steps: Weigh the raw materials according to the mass fractions, mix the main oxygenating agent, pH buffer, free radical scavenger and slow-release matrix evenly in a dry environment, and compress them into tablet-shaped oxygenating cores using a tablet press. Cellulose acetate and pH-sensitive polymer were dissolved in a mixed solvent to prepare a uniform coating solution; The sheet-like oxygenation core is placed in a coating machine, and the coating liquid is sprayed evenly under temperature and air control conditions to perform the first coating. After drying, an intelligent response coating layer is formed on the outside of the sheet-like oxygenation core. The outer layer of the intelligent response coating is coated a second time to form an outer coating, thereby preparing the pH-responsive slow-release long-acting aquatic oxygenating agent.

[0015] Furthermore, the mass ratio of the cellulose acetate to the pH-sensitive polymer is (1-3):1.

[0016] Furthermore, the mixed solvent is a mixture of acetone and water.

[0017] Furthermore, the coating solution used in the secondary coating is a beeswax or an ethanol solution of stearic acid.

[0018] To further enhance its long-lasting effect, this invention adds a hydrophobic, slow-degrading outer coating layer to the smart response coating layer. This outer coating slowly degrades in water, mainly serving as a physical barrier and extending the overall lifespan, without affecting the pH response function of the inner layer.

[0019] Thirdly, the present invention provides an application of the pH-responsive slow-release long-acting aquatic oxygenating agent in aquaculture and live animal transportation.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects: The pH-responsive, slow-release, long-acting aquatic oxygenator provided by this invention features intelligent slow release and water quality stabilization. This invention pioneers a pH-responsive oxygen release mechanism that automatically adjusts the oxygen release rate according to the actual chemical state of the water, achieving a leap from "passive release" to "intelligent regulation." It not only provides a stable oxygen supply for up to 24 hours but also effectively suppresses pH fluctuations during use, controlling pH increases to within 1.5, creating a more stable living environment.

[0021] The pH-responsive slow-release long-acting aquatic oxygenator provided by this invention is safe for aquatic organisms and has low stress: by adding pH buffers and free radical scavengers to the oxygenation core, the instantaneous peak values ​​of alkaline substances and reactive oxygen free radicals are reduced from the source, greatly reducing the risk of chemical burns and oxidative stress to fish gills and body surface.

[0022] The pH-responsive slow-release long-acting aquatic oxygenating agent provided by this invention has long-lasting and high efficiency: the multi-layer structure design (core slow-release matrix + intelligent coating + optional hydrophobic outer coating) makes the oxygen release curve more in line with the oxygen demand pattern of aquatic animals, reducing the frequency of application, and is particularly suitable for closed transportation systems (such as live fish transport vehicles and packaging bags) and pond bottom oxygenation where frequent water changes are not possible.

[0023] The pH-responsive, slow-release, long-acting aquatic oxygenating agent provided by this invention is environmentally friendly and easy to use: all raw materials can be food-grade or environmentally friendly, the final product has no harmful residues, and it can be prepared into tablets or granules for easy accurate measurement and application. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A comprehensive diagram illustrating the preparation process and oxygen release mechanism of the pH-responsive slow-release long-acting aquatic oxygenating agent provided by this invention. Detailed Implementation

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0029] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0030] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0031] This invention provides a pH-responsive slow-release long-acting aquatic oxygenator, comprising an oxygenation core, a smart-responsive coating layer, and an outer coating layer; the smart-responsive coating layer surrounds the oxygenation core; the outer coating layer surrounds the smart-responsive coating layer. The oxygen-enhancing core comprises a primary oxygenator, auxiliary agents, and a slow-release matrix; the auxiliary agents include a pH-controlled release agent and a free radical scavenger; the smart-responsive coating layer comprises cellulose acetate and a pH-sensitive polymer. Further, the smart-responsive coating layer accounts for 10%-30% of the weight of the oxygen-enhancing core.

[0032] In some preferred embodiments, the primary oxygenating agent is 50-70 parts by weight (exemplary, the primary oxygenating agent is 50, 70, and 60 parts), the pH buffer is 10-20 parts (exemplary, the pH buffer is 20, 10, and 15 parts), the free radical scavenger is 5-10 parts (exemplary, the free radical scavenger is 5, 7, and 10 parts), and the sustained-release matrix is ​​15-25 parts (exemplary, the sustained-release matrix is ​​20, 25, and 15 parts).

[0033] In some preferred embodiments, the primary oxygenating agent includes one or more of calcium peroxide, sodium percarbonate, and percarbonamide; and / or, the pH-release agent is selected from calcium dihydrogen phosphate or citric acid; and / or, the free radical scavenger is selected from silicates or urea; and / or, the sustained-release matrix is ​​selected from dextrin or soluble starch.

[0034] In some preferred embodiments, the pH-sensitive polymer is selected from chitosan, chitosan derivatives, or sodium alginate.

[0035] This invention also provides a method for preparing the pH-responsive slow-release long-acting aquatic oxygenating agent, comprising the following steps: Weigh the raw materials according to the mass fractions, mix the main oxygenating agent, pH buffer, free radical scavenger and slow-release matrix evenly in a dry environment, and compress them into tablet-shaped oxygenating cores using a tablet press. Cellulose acetate and pH-sensitive polymer were dissolved in a mixed solvent to prepare a uniform coating solution; The sheet-like oxygenation core is placed in a coating machine, and the coating liquid is sprayed evenly under temperature and air control conditions to perform the first coating. After drying, an intelligent response coating layer is formed on the outside of the sheet-like oxygenation core. The outer layer of the intelligent response coating is coated a second time to form an outer coating, thereby preparing the pH-responsive slow-release long-acting aquatic oxygenating agent.

[0036] In some preferred embodiments, the mass ratio of cellulose acetate to the pH-sensitive polymer is (1-3):1. Exemplary examples include mass ratios of cellulose acetate to the pH-sensitive polymer of 1:1, 3:1, and 2:1. In some preferred embodiments, the mixed solvent is a mixture of acetone and water.

[0037] In some preferred embodiments, the coating solution used for the secondary coating is a beeswax or an ethanol solution of stearic acid.

[0038] This invention also provides an application of the pH-responsive slow-release long-acting aquatic oxygenating agent in aquaculture and live animal transportation.

[0039] Figure 1 A comprehensive diagram illustrating the preparation process and oxygen release mechanism of the pH-responsive slow-release long-acting aquatic oxygenating agent provided by this invention.

[0040] The room temperature in this invention refers to 25±2℃.

[0041] Unless otherwise specified, all materials used in this invention are commercially available products.

[0042] In the embodiments of this invention, unless otherwise specified, "parts" refers to "parts by mass".

[0043] Example 1: A method for preparing a pH-responsive, slow-release, long-acting aquatic oxygenating agent. The raw materials used in the oxygenation core of this embodiment include: 50 parts calcium peroxide, 15 parts calcium dihydrogen phosphate, 5 parts food-grade magnesium silicate, and 20 parts dextrin.

[0044] The preparation method includes the following steps: S1. Mix calcium peroxide (passed through a 60-mesh sieve), calcium dihydrogen phosphate, food-grade magnesium silicate, and dextrin evenly in a dry environment, and press them into tablet-shaped oxygen-enriching cores (10 mm in diameter) using a tablet press (pressure of 8 kN). S2. Dissolve cellulose acetate and sodium alginate in a mixed solvent of acetone and water (acetone:water = 8:2, V / V), wherein the mass ratio of cellulose acetate and sodium alginate (viscosity ≥500 mPa·s) is 1:1, and the total mass concentration of cellulose acetate and sodium alginate is 5%, to prepare a uniform coating solution. S3. Place the sheet-like oxygenation core prepared in S1 into a coating machine, and apply it under controlled temperature (30℃) and controlled airflow (100m³ / h air volume). 3 Under the conditions of / h), the coating liquid prepared by S2 is uniformly sprayed for the first coating. The weight gain of the sheet-like oxygenation core after coating is controlled to be 30%. After drying, a smart response coating layer is formed. S4. Prepare a 4% (w / w) beeswax-ethanol solution as a secondary coating solution. Place the sheet-like oxygenation core coated with the smart response coating layer back into the coating machine, under controlled temperature (30℃) and controlled airflow (100m³ / h). 3 Under the condition of / h), a secondary coating solution is evenly sprayed to perform secondary coating. The weight gain after secondary coating is controlled to be 2%. After drying, a pH-responsive slow-release long-acting aquatic oxygenating agent is prepared.

[0045] Example 2: A method for preparing a pH-responsive, slow-release, long-acting aquatic oxygenating agent. The raw materials used in the oxygenation core of this embodiment include: 70 parts sodium percarbonate, 10 parts citric acid, 7 parts food-grade magnesium silicate, and 25 parts soluble starch.

[0046] The preparation method includes the following steps: S1. Sodium percarbonate (passed through an 80-mesh sieve), citric acid, food-grade magnesium silicate, and soluble starch are mixed evenly in a dry environment and pressed into a tablet core (10 mm in diameter) using a tablet press (pressure of 10 kN). S2. Dissolve cellulose acetate and chitosan (degree of deacetylation ≥90%) in a mixed solvent of acetone and water (acetone:water = 8:2, V / V), wherein the mass ratio of cellulose acetate to chitosan is 3:1, and the total mass concentration of cellulose acetate and sodium alginate is 5%, to prepare a uniform coating solution. S3. Place the sheet-like oxygenation core prepared in S1 into a coating machine, and apply it under controlled temperature (30℃) and controlled airflow (100m³ / h air volume). 3 Under the conditions of / h), the coating liquid prepared by S2 is uniformly sprayed for the first coating. The weight gain of the sheet-like oxygenation core after coating is controlled to be 10%. After drying, a smart response coating layer is formed. S4. Prepare a 4% (w / w) beeswax-ethanol solution as a secondary coating solution. Place the sheet-like oxygenation core coated with the smart response coating layer back into the coating machine, under controlled temperature (30℃) and controlled airflow (100m³ / h). 3 Under the condition of / h), a secondary coating solution is evenly sprayed to perform secondary coating. The weight gain after secondary coating is controlled to be 2%. After drying, a pH-responsive slow-release long-acting aquatic oxygenating agent is prepared.

[0047] Example 3: A method for preparing a pH-responsive, slow-release, long-acting aquatic oxygenating agent. The raw materials used in the oxygenation core of this embodiment include: 60 parts percarbonamide, 20 parts calcium dihydrogen phosphate, 10 parts urea, and 15 parts dextrin.

[0048] The preparation method includes the following steps: S1. Mix percarbamide (passed through a 60-mesh sieve), calcium dihydrogen phosphate, urea and dextrin evenly in a dry environment, and press them into tablet-shaped oxygen-enriching cores (10 mm in diameter) using a tablet press (pressure of 8 kN). S2. Dissolve cellulose acetate and sodium alginate in a mixed solvent of acetone and water (acetone:water = 8:2, V / V), wherein the mass ratio of cellulose acetate to sodium alginate is 2:1 and the total mass concentration of cellulose acetate and sodium alginate is 5%, to prepare a uniform coating solution. S3. Place the sheet-like oxygenation core prepared in S1 in a coating machine. Under controlled temperature (30℃) and controlled air conditions (air intake 100m3 / h), uniformly spray the coating liquid prepared in S2 to perform the first coating. Control the weight gain of the sheet-like oxygenation core after coating to 25%. After drying, a smart response coating layer is formed. S4. Prepare a 4% beeswax-ethanol solution as a secondary coating solution. Place the sheet-like oxygenating core coated with the intelligent response coating layer into the coating machine again. Under controlled temperature (30℃) and controlled airflow (100m3 / h), spray the secondary coating solution evenly to perform secondary coating. Control the weight gain after secondary coating to 2%. After drying, a pH-responsive slow-release long-acting aquatic oxygenating agent is prepared.

[0049] Comparative Example 1 Same as Example 1, except that no secondary coating was performed, and a sheet-like oxygenation core coated with a smart response coating layer was prepared.

[0050] Comparative Example 2 Same as Example 1, except that no first coating and second coating were performed to prepare the sheet-like oxygenation core.

[0051] Comparative Example 3 Same as Example 1, except that in S1, when preparing the sheet-like oxygen-enriching core, citric acid is replaced by soluble starch by mass.

[0052] Comparative Example 4 Same as Example 1, except that in S1, when preparing the sheet-like oxygen-enriching core, food-grade magnesium silicate is replaced by soluble starch.

[0053] Performance testing The experiment was conducted in an aquarium (size: length × width × height = 1.0 m × 0.6 m × 0.5 m), with the water volume controlled at 100 L. 100 crucian carp of the same density (average weight 10.2 ± 4.7 g) were placed in the aquarium. Oxygenating agents prepared in Examples 1-3 and Comparative Examples 1-4 were added, with 20 tablets added for each example. The experiment simulated a 24-hour transportation time requirement. The aquarium was kept in the dark at a temperature of 20 ± 1℃. Dissolved oxygen (DO), ammonia nitrogen content, and pH value were measured using a portable water quality analyzer. The survival rate after 24 hours was also examined. The results are shown in Table 1.

[0054] Table 1 Furthermore, the present invention measured DO every hour and found that within 24 hours, the DO fluctuation range of Example 1 was ±1.0 mg / L, the DO fluctuation range of Example 2 was ±1.2 mg / L, and the DO fluctuation range of Example 3 was ±1.1 mg / L; while the DO fluctuation range of Comparative Example 1 was ±4.0 mg / L, the DO fluctuation range of Comparative Example 2 was ±3.5 mg / L, the DO fluctuation range of Comparative Example 3 was ±2.9 mg / L, and the DO fluctuation range of Comparative Example 4 was ±1.9 mg / L.

[0055] The pH was also measured every hour. It was found that within 24 hours, the pH fluctuation range of Example 1 was ±1.2, the pH fluctuation range of Example 2 was ±1.1, and the pH fluctuation range of Example 3 was ±1.5; while the pH fluctuation range of Comparative Example 1 was ±2.5, the pH fluctuation range of Comparative Example 2 was ±3.4, the pH fluctuation range of Comparative Example 3 was ±2.9, and the pH fluctuation range of Comparative Example 4 was ±2.6.

[0056] The present invention also simultaneously observed the stress response of fish in Examples 1-3 and Comparative Examples 1-4. It was found that the fish in Comparative Examples 1-4 became agitated and even died in large numbers over time, while the fish in Examples 1-3 behaved normally and the number of deaths was significantly less than that in Comparative Examples 1-4.

[0057] The above experimental results show that the present invention systematically solves the three major problems of traditional oxygenation agents: "rapid release, pH spike, and stress" by introducing a pH-sensitive polymer to construct an intelligent responsive coating layer and synergistically adding buffers and free radical scavengers in the core, thus creating an intelligent oxygenation system that can self-regulate and interact with the environment.

[0058] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A pH-responsive, slow-release, long-acting aquatic oxygenating agent, characterized in that, It includes an oxygen-enhancing core, a smart-response coating layer, and an outer coating layer; the smart-response coating layer surrounds the outside of the oxygen-enhancing core; the outer coating layer surrounds the outside of the smart-response coating layer; The oxygen-enriching core includes a primary oxygenator, an auxiliary agent, and a slow-release matrix; the auxiliary agent includes a pH slow-release agent and a free radical scavenger; the smart-responsive coating layer includes cellulose acetate and a pH-sensitive polymer.

2. The pH-responsive slow-release long-acting aquatic oxygenating agent according to claim 1, characterized in that, The weight of the smart response coating layer accounts for 10%-30% of the weight of the oxygenation core.

3. The pH-responsive slow-release long-acting aquatic oxygenating agent according to claim 1, characterized in that, By weight, the main oxygenating agent is 50-70 parts, the pH buffer is 10-20 parts, the free radical scavenger is 5-10 parts, and the slow-release matrix is ​​15-25 parts.

4. The pH-responsive slow-release long-acting aquatic oxygenating agent according to claim 1, characterized in that, The primary oxygenating agent includes one or more of calcium peroxide, sodium percarbonate, and percarbonamide; and / or, The pH-release agent is selected from calcium dihydrogen phosphate or citric acid; and / or, The free radical scavenger is selected from silicates or urea; and / or, The slow-release matrix is ​​selected from dextrin or soluble starch.

5. The pH-responsive slow-release long-acting aquatic oxygenating agent according to claim 1, characterized in that, The pH-sensitive polymer is selected from chitosan, chitosan derivatives, or sodium alginate.

6. A method for preparing a pH-responsive, slow-release, long-acting aquatic oxygenating agent according to any one of claims 1-5, characterized in that, Includes the following steps: Weigh the raw materials according to the mass fractions, mix the main oxygenating agent, pH buffer, free radical scavenger and slow-release matrix evenly in a dry environment, and compress them into tablet-shaped oxygenating cores using a tablet press. Cellulose acetate and pH-sensitive polymer were dissolved in a mixed solvent to prepare a uniform coating solution; The sheet-like oxygenation core is placed in a coating machine, and the coating liquid is sprayed evenly under temperature and air control conditions to perform the first coating. After drying, an intelligent response coating layer is formed on the outside of the sheet-like oxygenation core. The outer layer of the intelligent response coating is coated a second time to form an outer coating, thereby preparing the pH-responsive slow-release long-acting aquatic oxygenating agent.

7. The preparation method according to claim 6, characterized in that, The mass ratio of cellulose acetate to pH-sensitive polymer is (1-3):

1.

8. The preparation method according to claim 6, characterized in that, The mixed solvent is a mixture of acetone and water.

9. The preparation method according to claim 6, characterized in that, The coating solution used for the secondary coating is an ethanol solution of beeswax or stearic acid.

10. The application of a pH-responsive slow-release long-acting aquatic oxygenating agent according to any one of claims 1-5 in aquaculture and live animal transportation.

Images