Gel-embedded slow-release oxygen material and preparation method thereof

Abstract

The invention relates to the technical field of eutrophic water and endogenous pollution treatment, and particularly discloses a preparation method of a gel-embedded slow-release oxygen material, which comprises the following steps: S1, mixing a stabilizer with a sodium alginate solution, and uniformly stirring to obtain an embedding layer precursor solution; the stabilizer comprises at least one of potassium chloride and polyvinylpyrrolidone; s2, mixing a porous material matrix loaded with oxygen with the embedding layer precursor solution, and uniformly stirring to form an uncrosslinked suspension; and S3, dropwise adding the obtained non-crosslinked suspension into a metal salt solution, and carrying out a curing reaction to obtain the gel-embedded slow-release oxygen material. The invention further discloses the gel-embedded slow-release oxygen material, and the gel-embedded slow-release oxygen material is prepared by the preparation method of the gel-embedded slow-release oxygen material. The scheme is used for solving the technical problems that oxygen of an existing oxygen-carrying porous material is easy to escape and cannot be slowly released for a long time, and the pH of a water body is influenced by byproducts existing in a chemical oxygen release agent.

Description

Technical Field

[0001] This invention relates to the field of eutrophic water body and endogenous pollution control technology, specifically to a gel-encapsulated slow-release oxygen material and its preparation method. Background Technology

[0002] Endogenous pollution is a significant source of eutrophication, primarily referring to nutrients such as nitrogen and phosphorus released from sediments. Effectively controlling the release of endogenous pollutants is crucial for managing eutrophication. The dissolved oxygen content at the sediment-water interface can alter the redox potential at this interface, thereby affecting the transformation of nitrogen and phosphorus forms in both phases and directly influencing the release of nitrogen and phosphorus from sediments. Therefore, increasing the dissolved oxygen concentration in water bodies, especially at the sediment-water interface, can inhibit the release of endogenous pollutants and control eutrophication.

[0003] Currently, there are two main types of slow-release oxygen technologies in the treatment of endogenous pollution: chemical oxygen release agent encapsulation method and porous material oxygen-supported nanobubble method.

[0004] I. Chemical Oxygen-Releasing Agent Encapsulation Method The chemical oxygen release agent encapsulation method involves combining solid oxygen release agents such as calcium peroxide (CaO2) and magnesium peroxide (MgO2) with coating materials such as alginate. Through ionic cross-linking, a gel material is formed. The physical barrier of the gel layer delays the contact between the oxygen release agent and water, thereby achieving slow oxygen release.

[0005] For example, patent publication number CN109574184A discloses a slow-release oxygen cationic crosslinking agent and its preparation method. Using calcium peroxide / magnesium peroxide as the oxygen release source, sodium alginate as the coating agent, and bentonite as an additive, a slow-release oxygen gel material is prepared through a drop-addition spheroidization process. This material can, to a certain extent, slow down the oxygen release rate and improve oxygen utilization.

[0006] However, the chemical oxygen release agent encapsulation method has inherent drawbacks: while oxygen release agents such as calcium peroxide and magnesium peroxide react with water to generate oxygen, they also cause the pH value of the water to rise, which impacts the aquatic ecosystem and affects the metabolic activity of bottom sediment microorganisms.

[0007] II. Porous Material Loading with Oxygen Nanobubbles The oxygen-loaded nanobubble method for porous materials involves placing porous materials (such as biochar, molecular sieves, diatomaceous earth, etc.) in a high-pressure oxygen environment. Oxygen is then loaded into the pores through physical adsorption, forming an oxygen-loaded porous material. During use, oxygen is released from the pores, achieving the purpose of oxygenation. This method is a purely physical process with no chemical byproducts and excellent environmental friendliness.

[0008] However, the oxygen-supported nanobubble method using porous materials faces significant challenges in practical applications: oxygen molecules are small and have a high diffusion coefficient, meaning that once the oxygen-supported porous material is removed from the high-pressure environment, the adsorbed oxygen easily escapes rapidly, leading to rapid oxygen loss and making it unsuitable for situations requiring long-term oxygen release. Currently, the problem of oxygen retention in oxygen-supported porous materials has not been effectively solved, limiting its application in practical engineering.

[0009] Sodium alginate is a natural polysaccharide with advantages such as low cost, high cost-effectiveness, environmental friendliness, good biocompatibility, and biodegradability. Those skilled in the art have attempted to use sodium alginate gel encapsulation technology to regulate the release rate of substances. For example, patent publication number CN115637156A discloses a core-shell structured slow-release oxidant material, which uses a porous material to pre-adsorb a solid oxidant (such as persulfate) as the core, and an additional oxidant encapsulated in sodium alginate gel as the shell, for in-situ chemical oxidation remediation of chlorinated hydrocarbon pollution in soil / groundwater. However, this technical solution targets the dissolution-diffusion of solid chemical oxidants to achieve chemical oxidation degradation. If applied to eutrophic water bodies and endogenous pollution control, it will still produce byproducts that affect the pH of the water body and impact the ecosystem. Summary of the Invention

[0010] The present invention aims to provide a gel-encapsulated slow-release oxygen material and its preparation method, so as to solve the technical problems of existing oxygen-carrying porous materials, such as easy oxygen escape, inability to provide long-term slow release, and the presence of by-products of chemical oxygen release agents that affect the pH of water.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a gel-encapsulated sustained-release oxygen material includes the following steps: S1. The stabilizer is mixed with sodium alginate solution and stirred until homogeneous to obtain an embedding layer precursor solution; the stabilizer includes at least one of potassium chloride and polyvinylpyrrolidone. S2. Mix the oxygen-loaded porous material matrix with the embedded layer precursor solution and stir until homogeneous to form an uncrosslinked suspension. S3. The obtained uncrosslinked suspension is added dropwise to the metal salt solution, and after a solidification reaction, a gel-encapsulated slow-release oxygen material is obtained.

[0012] Preferably, as an improvement, the concentration of the potassium chloride solution is 0.045%, and the addition ratio is 2 mL of potassium chloride solution per 100 mL of sodium alginate solution.

[0013] Preferably, as an improvement, the concentration of the polyvinylpyrrolidone solution is 1~8% w / v, and the addition ratio is 3 mL of polyvinylpyrrolidone solution per 100 mL of sodium alginate solution.

[0014] Preferably, as an improvement, the concentration of the polyvinylpyrrolidone solution is 3-5% w / v.

[0015] Preferably, as an improvement, in step S2, the oxygen-loaded porous material matrix is ​​prepared by vacuum pressure swing adsorption. The vacuum pressure swing adsorption method involves placing a porous material matrix into a high-pressure vacuum pump to create a vacuum, closing the vacuum valve, and then opening the O2 valve to carry oxygen. This vacuum-oxygen-carrying cycle is repeated multiple times.

[0016] Preferably, as an improvement, the mixing volume ratio of the oxygen-loaded porous material matrix to the embedding layer precursor solution is 1:1.25 to 1:2.

[0017] Preferably, as an improvement, in step S3, the metal cations in the metal salt solution include Ca. 2+ Zn 2 + Fe 3+ At least one of the following, wherein the mass concentration of the metal salt solution is 0.3 to 1% w / v.

[0018] Preferably, as an improvement, the metal salt solution is a soluble chloride salt solution.

[0019] Preferably, as an improvement, after the curing reaction in step S3, the process further includes: filtration and deionized water rinsing.

[0020] The present invention also provides a gel-embedded slow-release oxygen material, which is prepared by the method described above.

[0021] Compared with the prior art, the present invention has significant advantages and beneficial effects, specifically reflected in the following aspects: (1) In this invention, a porous material matrix is ​​used as an oxygen carrier, which serves to store and continuously release oxygen; the potassium chloride in the coating layer can regulate the charge distribution at the gas-liquid interface, K + Adsorption near the carboxyl groups of sodium alginate molecular chains can optimize the interfacial electrostatic environment, helping sodium alginate to be more stably adsorbed on the surface of oxygen-carrying porous materials. Polyvinylpyrrolidone (PVP) in the coating layer is a nonionic surfactant that can effectively reduce the gas-liquid interfacial tension and stabilize the oxygen nanobubbles released by the oxygen-carrying porous material through surface adsorption. Sodium alginate (SA) is the core material in the coating layer. Through cross-linking with metal cations, it forms slow-release gel microspheres, which helps to solve the problem of excessively fast oxygen release rate of oxygen-carrying porous materials and achieve a slow-release oxygen effect.

[0022] (2) Through systematic optimization of key parameters such as stabilizer composition and crosslinking agent concentration, the present invention enables the material prepared by the present invention to maintain stable oxygen release capacity after 35 days. Especially when the stabilizer contains both polyvinylpyrrolidone (PVP) and potassium chloride, the dissolved oxygen concentration is maintained at about 5.5 mg / L on the 35th day, which is significantly higher than that of porous material matrix without embedding and natural reoxygenation. This can meet the demand for long-term oxygenation in the treatment of pollution sources in rivers, lakes and reservoirs. Moreover, the oxygen release process will not produce by-products like the existing technology, thus ensuring that the slow-release material of the present invention will not affect the pH value of the water body.

[0023] (3) The present invention uses sodium alginate, porous materials, and potassium chloride as raw materials, all of which are widely available and biodegradable green materials. The vacuum pressure swing adsorption oxygen-carrying process is a purely physical process with no chemical residues. The equipment is simple and easy to operate, making it suitable for large-scale production. Attached Figure Description

[0024] Figure 1 This is a photograph of the gel-encapsulated slow-release oxygen material prepared in Example 1 of the present invention.

[0025] Figure 2 The oxygenation effect of adding gel-encapsulated slow-release oxygen material to anoxic water in Application Example 1 of this invention.

[0026] Figure 3 The oxygenation effect of adding gel-encapsulated slow-release oxygen materials prepared at different stabilizer concentrations to anoxic water bodies is shown in Application Example 2 of this invention.

[0027] Figure 4 The oxygenation effect of adding gel-encapsulated slow-release oxygen materials prepared at different metal salt solution concentrations in Example 3 of this invention to anoxic water bodies.

[0028] illustrate: Figure 2 , Figure 3 and Figure 4 In Example 5, due to application tests conducted at different times, random errors existed in the test conditions (such as differences in transfer and pouring speeds), resulting in slight differences in dissolved oxygen concentration. Figure 2 The stable dissolved oxygen concentration range of Example 5 was 5.3-5.6 mg / L. Figure 3 and Figure 4 The dissolved oxygen concentration in Example 5 is stable in the range of 5.5-5.9 mg / L. However, the overall trend of the three examples is basically consistent and falls within the normal fluctuation range, which does not affect the overall excellence and stability of the technical solution of the present invention. Detailed Implementation

[0029] The following detailed description illustrates the specific implementation method: This invention provides a method for preparing a gel-encapsulated sustained-release oxygen material, comprising the following steps: S1. After mixing the stabilizer with the sodium alginate solution, stir and mix well to obtain the embedding layer precursor solution; the stabilizer includes at least one of potassium chloride and polyvinylpyrrolidone (PVP); S2. Mix the oxygen-loaded porous material matrix with the embedding layer precursor solution and stir until homogeneous to form an uncrosslinked suspension. S3. The obtained uncrosslinked suspension is added dropwise to the metal salt solution, and after a solidification reaction, a gel-encapsulated slow-release oxygen material is obtained.

[0030] The above step S1 specifically includes: S11. Weigh a certain amount of sodium alginate, dissolve it in deionized water, and stir for at least 90 minutes until the sodium alginate is completely dissolved. S12. While stirring, add the appropriate proportion of stabilizer until the liquid is well mixed to obtain the embedding layer precursor solution.

[0031] In some embodiments of the present invention, the stirring speed is 300 rpm in steps S1 and S2.

[0032] In some embodiments of the present invention, the sodium alginate solution concentration is 1.0% w / v, and the solution concentration is the final concentration after the addition of the stabilizer; In some embodiments of the present invention, the stabilizer includes at least one of potassium chloride and polyvinylpyrrolidone (PVP), wherein the potassium chloride solution concentration is 0.045% w / v, and the addition ratio is 2 mL potassium chloride solution per 100 mL sodium alginate solution; the polyvinylpyrrolidone (PVP) solution concentration is 1~8% w / v, and the addition ratio is 3 mL polyvinylpyrrolidone (PVP) solution per 100 mL sodium alginate solution. The oxygen-loaded porous material matrix in step S2 above is prepared by vacuum pressure swing adsorption (VSA). Specifically, the VSA involves placing the porous material matrix in a high-pressure vacuum container and evacuating it for 2 hours. After closing the vacuum valve, the O2 valve is opened to load oxygen, setting the parameters to 0.8 MPa for 4 hours. This process is repeated three times to ensure the material is fully oxygen-loaded. After removing the oxygen-loaded porous material matrix from the high-pressure vacuum container, it is mixed with the embedding layer precursor solution and stirred until homogeneous. The stirring process is performed on a magnetic stirrer at a speed of 400 rpm.

[0033] In step S2, the volume ratio of the oxygen-loaded porous material matrix to the embedding layer precursor solution is 1:1.25 to 1:2.

[0034] In step S3, the obtained uncrosslinked suspension is added dropwise to the metal salt solution, and after a solidification reaction, a gel-encapsulated slow-release oxygen material is obtained. During the dropwise addition process, the uncrosslinked suspension is continuously stirred on a magnetic stirrer at a speed of 400 rpm.

[0035] The metal cations in the metal salt solution in step S3 include Ca. 2+ Zn 2+ Fe 3+ At least one of the following. Metal salt solutions include Ca. 2+ Zn 2+ Fe 3+ A soluble chloride salt solution. The mass concentration of the metal salt solution is 0.3% to 1% w / v, for example, 0.3% w / v.

[0036] The uncrosslinked suspension was added to the metal salt solution at a rate of 1 drop / second. The addition was performed using a peristaltic pump with a speed set to 20-30 rpm, for example, 20 rpm. The peristaltic pump tubing was made of silicone tubing with an inner diameter of 2 mm and an outer diameter of 4 mm.

[0037] The curing reaction in step S3 is carried out at room temperature for 15 minutes. After the curing reaction, the process includes filtration and cleaning. Deionized water is used for cleaning.

[0038] Compared to existing technologies, the gel-encapsulated slow-release oxygen material provided by this invention solves the problem of excessively rapid oxygen release in water from oxygen-carrying porous materials prepared by vacuum pressure swing adsorption. The stabilizer, by adjusting the charge distribution at the gas-liquid interface and reducing the interfacial tension, ensures that the sodium alginate solution is stably coated on the surface of the oxygen-carrying material, reducing oxygen escape before sodium alginate solidifies. The slow-release layer formed by the sodium alginate coating prolongs the oxygen release time, maintaining a high dissolved oxygen content in the overlying water and improving the redox potential at the sediment-water interface. This effectively controls the release of nitrogen and phosphorus from sediments, which is of great significance for controlling the release of endogenous pollutants from sediments.

[0039] Therefore, the gel-encapsulated slow-release oxygen material provided by this invention can offer a new option for controlling endogenous pollution in sediments.

[0040] The present invention does not impose any special restrictions on the source of the raw materials used above, and they can be commercially available.

[0041] To further illustrate the present invention, the following detailed description of a gel-encapsulated sustained-release oxygen material, its preparation method, and its application, in conjunction with embodiments, is provided by the present invention, but should not be construed as limiting the scope of protection of the present invention.

[0042] Example 1 1) Preparation of oxygen-loaded porous material matrix: Take 100 ml of coconut shell biochar powder (particle size 200 mesh) and place it in an oxygen-carrying device for oxygen loading. During operation, place the material into the reactor and tighten the bolts to form a sealed space. Turn on the vacuum pump to evacuate the reactor, ensuring the pressure inside the reactor is -0.09 MPa, and maintain this process for 2 hours. After evacuation, close the evacuation valve, open the charging valve, and open the oxygen cylinder valve. Control the oxygen supply pressure through the pressure reducing valve to maintain the pressure inside the reactor at 0.8 MPa for 4 hours. Repeat this process three times to ensure sufficient oxygen loading on the porous material. After oxygenation, open the evacuation valve to release gas and reduce pressure. Once the pressure in the reactor has decreased to normal, loosen the bolts and remove the oxygen-carrying material for immediate use.

[0043] 2) Preparation of the embedding layer precursor solution: Weigh 0.045 g of potassium chloride and prepare 100 ml of 0.045% w / v potassium chloride solution. Weigh 1.5 g of sodium alginate, add 100 ml of deionized water, place on a magnetic stirrer, and stir at 300 rpm for 90 minutes or more until the sodium alginate is completely dissolved. Add 3 ml of the 0.045% w / v potassium chloride solution, transfer the mixture to a 150 ml volumetric flask, and standardize to 150 ml with deionized water to obtain a final sodium alginate solution with a concentration of 1% w / v, i.e., 150 ml of embedding layer precursor solution.

[0044] 3) Preparation of gel-encapsulated sustained-release oxygen materials: Weigh 5g of anhydrous calcium chloride and add deionized water to prepare a 1% w / v calcium chloride solution. After removing the oxygen-loaded porous material matrix from the reactor, quickly pour the embedding layer precursor solution and magnetic stirring rotor into a beaker containing the oxygen-carrying material, and stir at 400 rpm on a magnetic stirrer. After mixing, an uncrosslinked suspension is obtained. Use a peristaltic pump to uniformly drop the uncrosslinked suspension into the 1% w / v calcium chloride solution for curing reaction. The peristaltic pump speed is set to 20 rpm. The peristaltic pump tube is a silicone tube with an inner diameter of 2 mm and an outer diameter of 4 mm. The rate at which the uncrosslinked suspension is dropped into the calcium chloride solution is approximately 1 drop / second. After all the uncrosslinked suspension has been dropped into the calcium chloride solution, allow it to stand at room temperature for 15 minutes to cure. After curing, filter out the material and wash it with deionized water to obtain the gel-encapsulated slow-release oxygen material.

[0045] Example 2 The difference from Example 1 is as follows: Replace the 1% w / v calcium chloride solution in step 3) with a 0.3% w / v calcium chloride solution.

[0046] Example 3 The difference from Example 1 is as follows: Replace the coconut shell biochar in step 1) with bamboo biochar with a particle size of 300 mesh.

[0047] Example 4 The difference from Example 1 is as follows: Replace the coconut shell biochar in step 1) with walnut shell biochar, with a particle size of 200 mesh.

[0048] Example 5 The difference from Example 1 is as follows: In step 2), polyvinylpyrrolidone (PVP) was added as one of the stabilizers. Specifically, 5g of PVP was weighed and prepared into 100ml of 5% w / v PVP solution. After the sodium alginate was completely dissolved, 3ml of 0.045% w / v potassium chloride solution and 4.5ml of 5% w / v PVP solution were added. The solution was then standardized to 150ml with deionized water to obtain a final sodium alginate solution with a concentration of 1% w / v, i.e., 150ml of embedding layer precursor solution.

[0049] Example 6 The difference from Example 5 is as follows: Replace the 5% w / v polyvinylpyrrolidone (PVP) in step 2) with 3% w / v polyvinylpyrrolidone (PVP).

[0050] Example 7 The difference from Example 5 is as follows: Replace the 1% w / v calcium chloride solution in step 3) with a 0.3% w / v calcium chloride solution.

[0051] Comparative Example 1 The difference from Example 1 is as follows: After oxygen loading, coconut shell biochar powder can be used directly without gel encapsulation.

[0052] Comparative Example 2 The difference from Example 1 is as follows: In step 2), potassium chloride is not added as a stabilizer.

[0053] Comparative Example 3 The difference from Example 5 is as follows: Replace the 5% w / v polyvinylpyrrolidone (PVP) in step 2) with 10% w / v polyvinylpyrrolidone (PVP).

[0054] Comparative Example 4 The difference from Example 1 is as follows: Replace 5% w / v polyvinylpyrrolidone (PVP) in step 2) with 0.5% w / v polyvinylpyrrolidone (PVP).

[0055] Comparative Example 5 The difference from Example 5 is as follows: Replace the 1% w / v calcium chloride solution in step 3) with a 3% w / v calcium chloride solution.

[0056] Application Example 1 The prepared gel-encapsulated slow-release oxygen material was used to conduct oxygenation experiments on anoxic water bodies. The specific procedures included: Before the experiment, surface sediments and overlying water were collected from water bodies with potential endogenous pollution using a sediment sampler. The collected sediment samples were sieved through an 80-mesh sieve and mixed thoroughly before use. The water samples were sieved through a No. 25 phytoplankton net before use. During the experiment, a 1000ml tall beaker was used as the experimental apparatus. Pretreated sediments and overlying water were added to the apparatus, with a water-to-sediment volume ratio of 3:1. Five experimental groups were set up, one of which served as a blank control group. The other four groups were prepared using materials obtained in Comparative Example 1, Example 1, Example 2, and Example 5, respectively. During the experiment, the experimental apparatus was placed in a photocatalytic incubator to ensure stable environmental conditions. The temperature was set at 25℃, and the light-dark ratio was 12h:12h. Dissolved oxygen concentration was measured daily.

[0057] Application Example 2 The prepared gel-encapsulated slow-release oxygen material was used to conduct oxygenation experiments on anoxic water bodies. The specific procedures included: Before the experiment, surface sediments and overlying water were collected from water bodies with potential endogenous pollution using a sediment sampler. The collected sediment samples were sieved through an 80-mesh sieve and mixed thoroughly before use. The water samples were sieved through a No. 25 phytoplankton net before use. During the experiment, a 1000ml tall beaker was used as the experimental apparatus. Pretreated sediments and overlying water were added to the apparatus, with a water-to-sediment volume ratio of 3:1. Six experimental groups were set up, one of which served as a blank control group. The other five groups were prepared using materials obtained from Comparative Examples 2, 3, 4, 5, and 6, respectively. During the experiment, the experimental apparatus was placed in a photocatalytic incubator to ensure stable environmental conditions. The temperature was set at 25℃, and the light-dark ratio was 12h:12h. Dissolved oxygen concentration was measured daily.

[0058] Application Example 3 The prepared gel-encapsulated slow-release oxygen material was used to conduct oxygenation experiments on anoxic water bodies. The specific procedures included: Before the experiment, surface sediments and overlying water were collected from water bodies with potential endogenous pollution using a sediment sampler. The collected sediment samples were sieved through an 80-mesh sieve and mixed thoroughly before use. The water samples were sieved through a No. 25 phytoplankton net before use. During the experiment, a 1000ml tall beaker was used as the experimental apparatus. Pretreated sediments and overlying water were added to the apparatus, with a water-to-sediment volume ratio of 3:1. Four experimental groups were set up, one as a blank control group, and the other three groups were supplemented with materials prepared according to Comparative Example 5, Example 5, and Example 7, respectively. During the experiment, the experimental apparatus was placed in a photocatalytic incubator to ensure stable environmental conditions. The temperature was set at 25℃, and the light-dark ratio was 12h:12h. Dissolved oxygen concentration was measured daily.

[0059] Figure 2 To demonstrate the oxygenation effect of the gel-encapsulated slow-release oxygen material in Example 1 of this invention when added to anoxic water, [the following is a summary of the invention's application]. Figure 2 It can be seen that the oxygen-carrying porous material prepared by vacuum pressure swing adsorption without gel embedding rapidly releases oxygen to a peak value after being added to the system. After the oxygen release ends, the dissolved oxygen concentration in the system decreases. However, the gel embedding of the present invention effectively prolongs the oxygen release time of the oxygen-carrying porous material. The material after gel embedding releases oxygen stably throughout the experiment, keeping the dissolved oxygen concentration in the system at a high level. In particular, Example 5, in which both polyvinylpyrrolidone (PVP) and potassium chloride are used as stabilizers, demonstrates the synergistic effect of KCl and PVP—KCl… + Adjusting the gas-liquid interfacial charge optimizes the adsorption of sodium alginate on the oxygen-carrying material surface; PVP reduces interfacial tension, stabilizing the release of oxygen nanobubbles. Together, these two mechanisms achieve a more stable and sustained oxygen release.

[0060] In Comparative Example 1, without the embedded material, rapid oxygen release began, and after about 20 days, the dissolved oxygen concentration was almost the same as that of the control group with natural reoxygenation (Comparative Example 1 had a dissolved oxygen concentration of about 3.3 mg / L after day 23, while the control group had a concentration of about 3 mg / L). The material prepared by this invention can achieve long-term oxygenation, and the most preferred embodiment 5 still maintains stable oxygen release capacity even after more than 30 days, with a dissolved oxygen concentration of about 5.5 mg / L.

[0061] Figure 3 To illustrate the oxygenation effect of gel-encapsulated slow-release oxygen materials prepared at different stabilizer concentrations in Example 2 of this invention when added to anoxic water bodies, Comparative Example 1 shows a gel-encapsulated slow-release oxygen material without added stabilizer. Figure 3It can be seen that without the addition of stabilizers, oxygen is prone to escape before the curing reaction, resulting in a low total oxygen release of the material. In addition, when the concentration of polyvinylpyrrolidone (PVP) is too high, it will lead to over-embedding of the material and a decrease in oxygen release effect. When the concentration of PVP is too low, the internal structure of the gel is not stable enough, which will lead to uneven oxygen release rate. The embedding and slow release oxygen effects of Examples 5 and 6 are the best within the PVP concentration range.

[0062] Figure 4 To demonstrate the oxygenation effect of the gel-encapsulated slow-release oxygen material prepared at different metal salt solution concentrations in Example 3 of this invention when added to anoxic water, it was found that when the metal salt concentration was too low, the material could not cross-link and form. When the metal salt concentration was too high, it would lead to excessive cross-linking of sodium alginate, forming a dense shell that hindered oxygen release. Figure 4 The comparison of Example 7 (0.3% w / v calcium chloride solution), Example 5 (1% w / v calcium chloride solution), and Comparative Example 5 (3% w / v calcium chloride solution) demonstrates that the crosslinking agent concentration is a key parameter for controlling the gel structure and oxygen release performance; the gel obtained by crosslinking with 0.3-1.0% w / v calcium chloride solution has a good oxygen release effect when encapsulating slow-release oxygen materials.

[0063] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a gel-encapsulated sustained-release oxygen material, characterized in that, Includes the following steps: S1. The stabilizer is mixed with sodium alginate solution and stirred until homogeneous to obtain an embedding layer precursor solution; the stabilizer includes at least one of potassium chloride and polyvinylpyrrolidone. S2. Mix the oxygen-loaded porous material matrix with the embedded layer precursor solution and stir until homogeneous to form an uncrosslinked suspension. S3. The obtained uncrosslinked suspension is added dropwise to the metal salt solution, and after a solidification reaction, a gel-encapsulated slow-release oxygen material is obtained.

2. The method for preparing a gel-encapsulated sustained-release oxygen material according to claim 1, characterized in that: The potassium chloride solution concentration is 0.045%, and the addition ratio is 2 mL of potassium chloride solution per 100 mL of sodium alginate solution.

3. The method for preparing a gel-encapsulated sustained-release oxygen material according to claim 1, characterized in that: The concentration of the polyvinylpyrrolidone solution is 1-8% w / v, and the addition ratio is 3 mL of polyvinylpyrrolidone solution per 100 mL of sodium alginate solution.

4. The method for preparing a gel-encapsulated sustained-release oxygen material according to claim 3, characterized in that: The concentration of the polyvinylpyrrolidone solution is 3-5% w / v.

5. The method for preparing a gel-encapsulated sustained-release oxygen material according to claim 1, characterized in that: In step S2, the oxygen-loaded porous material matrix is ​​prepared by vacuum pressure swing adsorption. The vacuum pressure swing adsorption method involves placing a porous material matrix into a high-pressure vacuum pump to create a vacuum, closing the vacuum valve, and then opening the O2 valve to carry oxygen. This vacuum-oxygen-carrying cycle is repeated multiple times.

6. The method for preparing a gel-encapsulated sustained-release oxygen material according to claim 5, characterized in that: The volume ratio of the oxygen-loaded porous material matrix to the embedding layer precursor solution is 1:1.25 to 1:

2.

7. The method for preparing a gel-encapsulated sustained-release oxygen material according to claim 6, characterized in that: In step S3, the metal cations in the metal salt solution include Ca. 2+ Zn 2+ Fe 3+ At least one of the following, wherein the mass concentration of the metal salt solution is 0.3 to 1% w / v.

8. The method for preparing a gel-encapsulated sustained-release oxygen material according to claim 7, characterized in that: The metal salt solution is a soluble chloride salt solution.

9. The method for preparing a gel-encapsulated sustained-release oxygen material according to claim 1, characterized in that: After the curing reaction in step S3, the process also includes: filtration and deionized water rinsing.

10. A gel-encapsulated sustained-release oxygen material, characterized in that, It was prepared by the method of any one of claims 1-9 for preparing gel-encapsulated slow-release oxygen material.

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