A stepwise disintegration and oxygen release composite material and a preparation method thereof

Abstract

The application provides a step-by-step disintegration and oxygen release composite material and a preparation method thereof, which comprises three layers of an inner core layer, an intermediate layer and a surface layer; the material of the inner core layer is composed of calcium peroxide and physically cross-linked polyvinyl alcohol (PVA), wherein the content of calcium peroxide is 30-80 wt%, the content of PVA is 20-70 wt%, and the alcoholysis degree of PVA is more than 99%; the material of the intermediate layer is composed of calcium peroxide, physically cross-linked PVA, a water-soluble binder and a tackifier, wherein the water-soluble binder is polyethylene glycol, the tackifier is xanthan gum or sodium alginate, the content of calcium peroxide is 30-80 wt%, the content of PVA is 10-20 wt%, the alcoholysis degree of PVA is more than 99%, the content of polyethylene glycol is 0-20 wt%, and the content of xanthan gum or sodium alginate is 0-1 wt%; and the material of the surface layer is composed of calcium peroxide, a water-soluble binder and a tackifier, wherein the water-soluble binder is polyethylene glycol, the tackifier is xanthan gum or sodium alginate, the content of calcium peroxide is 40-80 wt%, the content of polyethylene glycol is 20-60 wt%, and the content of xanthan gum or sodium alginate is 0-1 wt%. The oxygen release rate is controlled through the three-layer structure design to achieve the purpose of long-acting oxygen release.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of river sediment treatment, and particularly relates to a gradually disintegrating and slow-release oxygen composite material and a preparation method thereof. BACKGROUND

[0002] In the treatment of river sediment, oxygenation is a common method, which mainly improves water quality by increasing the concentration of dissolved oxygen in the overlying water of the sediment to promote the biochemical degradation of various pollutants by aerobic microorganisms. The oxygenation methods mainly include mechanical aeration and oxygen releasing agent (ORC) addition. The mechanical aeration method needs to lay aeration equipment, has high operation energy consumption, and has poor oxygenation effect on the overlying water of the sediment. Moreover, the construction and operation and maintenance are not convenient. The oxygen releasing agent can be added to the sediment, and the oxygen generated can directly act on various sediments to form an aerobic environment. Moreover, the oxygen bubbles generated are small, can fully contact the sediment and its overlying water during the diffusion process, and maximize the role of oxygenation in repairing water quality. The oxygen releasing agent is convenient to add, has low construction and operation cost, and is more convenient to use in the repair of river water.

[0003] The oxygen releasing agent used for water repair is mainly peroxide, including calcium peroxide (CaO2), magnesium peroxide (MgO2), hydrogen peroxide (H2O2) and sodium percarbonate (Na2CO3·H2O2), etc. They can release oxygen by reacting with water after being put into water, thereby increasing the dissolved oxygen value in water. Among them, calcium peroxide has a low oxygen release rate and a long sustained release time, and has high oxygen content and low cost, so it is the most commonly used oxygen releasing agent material. However, calcium peroxide is generally in powder form, which will fully contact and react with water after being put into water, resulting in excessive initial oxygen release, which exceeds the saturation dissolved oxygen degree of water and the requirement of oxidative degradation of pollutants, and the oxygen release lacks sustainability, so it needs to be added in excess for multiple times, and therefore a slow-release technology is needed to control the oxygen release rate.

[0004] At present, the common method for preparing slow-release ORC is embedding, that is, embedding calcium peroxide by different carriers to prepare a composite ORC, so as to control the oxygen release rate and achieve the purpose of long-acting oxygen release. Common embedding carriers include cement, bentonite, sodium alginate, sodium humate, polyhydroxyalkanoate (PHA), polyvinyl alcohol (PVA) and the like. However, the existing embedding type slow-release ORC is generally embedded by a single layer of carrier and oxygen releasing agent, and the oxygen release rate is controlled by adjusting the embedding amount. In order to ensure long-acting oxygen release, a relatively small oxygen release rate is generally controlled, so that the oxygen release amount is low in a relatively long period at the initial stage of release, and the dissolved oxygen value in the water body is increased too slowly to meet the needs of oxidative degradation in the sediment. SUMMARY

[0005] In order to solve the above problems existing in the prior art, the purpose of the present application is to provide a gradually disintegrating and slow-release oxygen composite material and a preparation method thereof, so as to overcome the above-mentioned shortcomings and deficiencies existing in the prior art.

[0006] To achieve the above object, the application adopts the following technical scheme:

[0007] A step-by-step disintegration and oxygen-releasing composite material comprises three layers of inner core layer, intermediate layer and surface layer from inside to outside, the material of the inner core layer is calcium peroxide and physically cross-linked PVA; the material of the intermediate layer is calcium peroxide, water-soluble substance and non-water-soluble substance; the material of the surface layer is calcium peroxide and water-soluble substance.

[0008] Optionally, the content of calcium peroxide in the inner core material is 30-80wt%, and / or the content of polyvinyl alcohol in the inner core material is 20-70wt%, and the alcoholysis degree of polyvinyl alcohol is more than 99%.

[0009] Optionally, the non-water-soluble substance of the intermediate layer is physically cross-linked PVA, and the water-soluble substance of the intermediate layer comprises water-soluble binder and tackifier, wherein the water-soluble binder is polyethylene glycol, and the tackifier is xanthan gum or sodium alginate.

[0010] Optionally, the material of the intermediate layer comprises the following components:

[0011]

[0012] Optionally, the water-soluble substance of the surface layer comprises water-soluble binder and tackifier, wherein the water-soluble binder is polyethylene glycol, and the tackifier is xanthan gum or sodium alginate.

[0013] Optionally, the material of the surface layer comprises the following components:

[0014] Calcium peroxide 40-80%;

[0015] Polyethylene glycol 20-60wt%;

[0016] Xanthan gum or sodium alginate 0-1wt%.

[0017] Optionally, the shape of the step-by-step disintegration and oxygen-releasing composite material is a columnar shape with a diameter of 5-25mm and a length of 10-20mm, preferably a diameter of 10-12mm; wherein the thickness of the inner core layer is 2-8mm, the thickness of the intermediate layer is 5-10mm, and the thickness of the surface layer is 2-10mm, preferably the thickness of the inner core layer is 3-5mm, preferably the thickness of the intermediate layer is 5-6mm, and preferably the thickness of the surface layer is 2-5mm.

[0018] The application further provides a preparation method of the step-by-step disintegration and oxygen-releasing composite material, comprising the following steps:

[0019] Core layer material preparation: PVA particles are dissolved in deionized water under stirring at 80-95°C, the mass concentration of PVA aqueous solution is 5-20%, the completely dissolved PVA solution is cooled to room temperature, then cooled to 0-10°C under refrigeration, and is recorded as embedding liquid 1; calcium peroxide is added to embedding liquid 1, and is uniformly mixed by mechanical stirring, the stirring time is 5-20 min, and the stirring speed is 100-300 rpm, to obtain a flowable paste, which is recorded as mixture 1; mixture 1 is extruded by a single screw extruder to obtain the core layer material;

[0020] Intermediate layer material preparation: PVA particles are dissolved in deionized water under stirring at 80-95°C, the mass concentration of PVA aqueous solution is 2-10%; polyethylene glycol, xanthan gum or sodium alginate is dissolved in deionized water under stirring at room temperature to form a mixed solution; the mixed solution and the PVA solution are uniformly mixed by stirring at room temperature in a certain proportion, and is recorded as embedding liquid 2; calcium peroxide is added to embedding liquid 2, and is uniformly mixed by stirring, the stirring time is 5-20 min, and the stirring speed is 100-300 rpm, to obtain a flowable paste, which is recorded as mixture 2; mixture 2 is extruded by a single screw extruder to prepare the intermediate layer material;

[0021] Surface layer material preparation: polyethylene glycol, xanthan gum or sodium alginate is dissolved in deionized water under stirring at room temperature to obtain a mixed solution, which is recorded as embedding liquid 3; calcium peroxide is added to embedding liquid 3, and is uniformly mixed by stirring, the stirring time is 5-20 min, and the stirring speed is 100-300 rpm, to obtain a flowable paste, which is recorded as mixture 3; mixture 3 is extruded by a single screw extruder to prepare the surface layer material;

[0022] Material compounding: the core layer material, the intermediate layer material and the surface layer material are compounded in a single-hole head, and are extruded to obtain an extruded material strip with a three-layer structure and a diameter of 5-25 mm, the intermediate layer is wrapped in the core layer, and the surface layer is wrapped in the intermediate layer; the center of the material strip is mixture 1, the intermediate layer is mixture 2, and the surface layer is mixture 3; the compounded extruded material is cut at the extruder head to obtain columnar materials with a length of 10-20 mm, and then is immediately frozen at-20°C for 8-12 hours, then is thawed for 4 hours, and then is repeatedly frozen and thawed for 2-4 times, to obtain the final product.

[0023] Optionally, in the core layer material preparation, the PVA concentration is preferably 8-10 wt%, and / or

[0024] The completely dissolved PVA solution is preferably cooled to 5°C under refrigeration, and / or

[0025] The mass ratio of calcium peroxide to embedding liquid 1 is 1:1-1:3.

[0026] Optionally, in the preparation of the intermediate layer material, the concentration of polyethylene glycol in the mixed solution is 2-15wt%, and the concentration of xanthan gum or sodium alginate is 0-2wt%, wherein the concentration of polyethylene glycol solution is preferably 5-10wt%, and the concentration of xanthan gum or sodium alginate is preferably 0-0.5wt%; and / or

[0027] The mass ratio of the mixed solution to the PVA solution is 1:1-1:5; and / or

[0028] The mass ratio of calcium peroxide to the embedding solution 2 is 1:1-1:3.

[0029] Optionally, in the preparation of the surface layer material, the concentration of polyethylene glycol in the mixed solution is 5-20wt%, and the concentration of xanthan gum or sodium alginate is 0-2wt%, wherein the concentration of polyethylene glycol solution is preferably 5-10wt%, and the concentration of xanthan gum or sodium alginate is preferably 0-0.5wt%; and / or

[0030] The mass ratio of calcium peroxide to the embedding solution 3 is 1:1-1:3.

[0031] By adopting the technical scheme, the present application has the following beneficial effects:

[0032] 1. The product has the characteristics of gradual disintegration, stable oxygen release rate for a long time, and high utilization rate of calcium peroxide. The traditional calcium peroxide slow-release oxygen material has a high initial oxygen release rate after being put into water, but the oxygen release rate will decrease significantly in the middle and late stages. This is because the calcium hydroxide microcrystals formed by the reaction of the surface layer calcium peroxide with water will cover and block the water permeation channel, reducing the contact probability of the inner layer calcium peroxide with water, resulting in a significant decrease in the oxygen release rate, which cannot fully meet the needs of river sediment microorganisms for oxygen consumption. In a more serious case, the inner layer calcium peroxide will never react with water, resulting in a low utilization rate of calcium peroxide. The internal structure of the product is a multi-layer gradient structure. The surface embedding agent is a mixture of water-soluble substances, i.e. PEG and one of sodium alginate or xanthan gum, which will gradually dissolve in water, causing the surface to disintegrate, thereby breaking the calcium hydroxide microcrystal shell formed by the reaction of the surface layer calcium peroxide, achieving rapid oxygen release in the initial stage, rapidly increasing the DO in the overlying water to the saturation level, and facilitating water penetration into the inner layer. The intermediate layer embedding agent is a mixture of water-soluble and water-insoluble substances, such as a mixture of physically cross-linked PVA gel and PEG, sodium alginate or xanthan gum. When the water-soluble substances such as PEG, sodium alginate or xanthan gum dissolve, holes are formed in the intermediate layer, facilitating water penetration and maintaining a moderate oxygen release rate. The inner core layer embedding agent is a water-insoluble substance, such as a physically cross-linked PVA gel. The PVA gel layer still has certain oxygen and water permeability, and the oxygen release rate is relatively low, which can achieve long-term oxygen release. At the same time, the inner core layer has a small particle size, and the calcium peroxide can ensure that it is eventually fully reacted with water, resulting in a high utilization rate.

[0033] 2. The oxygen release rate curve can be adjusted over a long period of time, offering a high degree of freedom in adjustment. The oxygen release cycle and rate can be flexibly adjusted according to actual needs. Existing slow-release oxygen materials are generally homogeneous systems, consisting of a uniform mixture of oxygen-releasing agent and encapsulating agent. The oxygen release rate is generally relatively fixed, and depending on the properties of the encapsulating agent, it often exhibits characteristics of being too fast or too slow, making it impossible to freely adjust the oxygen release rate over a long period. If the encapsulating agent is hydrophobic, water penetration is relatively slow, resulting in a low oxygen release rate. This fails to achieve rapid oxygenation in the initial stage of deployment, failing to meet the oxygen consumption needs of aquatic microorganisms. Conversely, if the encapsulating agent is hydrophilic, such as…, the oxygen release rate is relatively high, causing excessively rapid increase in dissolved oxygen (DO) in the overlying water during the initial deployment stage, exceeding the water's saturation point and wasting released oxygen, thus shortening the oxygen release cycle. This product has a three-layer structure. It can achieve rapid oxygenation in the initial stage, maintain a relatively moderate oxygen release rate in the middle stage, and maintain a low oxygen release rate in the later stage. The oxygen release rate can be freely controlled by adjusting the composition of the encapsulating agent in each layer and the thickness of each layer, thereby meeting the actual needs of ecological restoration of different water bodies.

[0034] 3. Environmentally friendly and non-toxic encapsulating agents. The encapsulating agents used in this product are all environmentally friendly and non-toxic synthetic or natural polymers. No other toxic additives are added during the preparation of the oxygen-releasing material. Water-soluble PEG, xanthan gum, and sodium alginate are dissolved in water, and the PVA crosslinking uses a freeze-thaw cycle physical crosslinking method, avoiding the use of toxic crosslinking agents. Attached Figure Description

[0035] Figure 1 The oxygen release curves are for the oxygen-releasing agents in Examples 1-5 and the comparative examples of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] Example 1:

[0038] PVA (polyvinyl alcohol) particles were dissolved in deionized water under stirring at 80-95℃ to prepare a 10wt% PVA solution. The solution was cooled to room temperature and then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 1.

[0039] PVA particles were dissolved in deionized water under stirring at 80-95℃ to prepare a 5wt% PVA solution. The solution was then cooled to room temperature. Separately, PEG and xanthan gum were stirred and dissolved in deionized water at room temperature. The concentration of PEG in this solution was 5wt%, and the concentration of xanthan gum was 0.05%. This solution was then mixed with the 5wt% PVA solution at a mass ratio of 1:1. The resulting mixture was then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 2.

[0040] PEG and xanthan gum were stirred and dissolved in deionized water at room temperature. The concentration of PEG (polyethylene glycol) in the solution was 10 wt%, and the concentration of xanthan gum was 0.1%. Then, it was mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 3.

[0041] In a three-layer co-extrusion unit containing three single-screw extruders, mixtures 1, 2, and 3 are extruded separately and compounded within a single-hole die head. The resulting extruded material is a three-layer structure with a diameter of 20 mm. The center layer is mixture 1 with a thickness of 6 mm, the middle layer is mixture 2 with a thickness of 8 mm, and the outermost layer is mixture 3 with a thickness of 6 mm. The extruded material is cut into 10 mm long cylindrical pieces at the die head and immediately frozen at -20°C for 8 hours, then thawed for 4 hours, and then frozen again. This process is repeated three times to obtain the final product.

[0042] Example 2:

[0043] PVA particles were dissolved in deionized water at 80-95℃ with stirring to prepare a 10wt% PVA solution (embedding solution 1). The solution was cooled to room temperature and then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 1.

[0044] PVA particles were dissolved in deionized water at 80-95℃ with stirring to prepare a 2wt% PVA solution. The solution was then cooled to room temperature. Separately, PEG and xanthan gum were dissolved in deionized water with stirring at room temperature. The concentration of PEG in this solution was 10wt% and the concentration of xanthan gum was 0.05%. This solution was then mixed with the 2wt% PVA solution at a mass ratio of 1:2. The resulting mixture was then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 2.

[0045] PEG and xanthan gum were stirred and dissolved in deionized water at room temperature. The concentration of PEG in the solution was 10 wt%, and the concentration of xanthan gum was 0.1%. Then, it was mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 3.

[0046] In a three-layer co-extrusion unit containing three single-screw extruders, mixtures 1, 2, and 3 are extruded separately and compounded within a single-hole die head. The resulting extruded material is a three-layer structure with a diameter of 20 mm. The center layer is mixture 1 with a thickness of 6 mm, the middle layer is mixture 2 with a thickness of 8 mm, and the outermost layer is mixture 3 with a thickness of 6 mm. The extruded material is cut into 10 mm long cylindrical pieces at the die head and immediately frozen at -20°C for 8 hours, then thawed for 4 hours, and then frozen again. This process is repeated three times to obtain the final product.

[0047] Example 3:

[0048] PVA particles were dissolved in deionized water at 80-95℃ with stirring to prepare a 10wt% PVA solution (embedding solution 1). The solution was cooled to room temperature and then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 1.

[0049] PVA particles were dissolved in deionized water at 80-95℃ with stirring to prepare a 2wt% PVA solution. The solution was then cooled to room temperature. PEG was then dissolved in deionized water at room temperature with stirring. The PEG concentration in this solution was 10wt%. This solution was then mixed with the 2wt% PVA solution at a mass ratio of 1:3. The resulting mixture was then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 2.

[0050] PEG and sodium alginate were stirred and dissolved in deionized water at room temperature. The concentration of PEG in the solution was 10 wt%, and the concentration of sodium alginate was 0.1%. Then, it was mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 3.

[0051] In a three-layer co-extrusion unit containing three single-screw extruders, mixtures 1, 2, and 3 are extruded separately and compounded within a single-hole die head. The resulting extruded material is a three-layer structure with a diameter of 20 mm. The center layer is mixture 1 with a thickness of 6 mm, the middle layer is mixture 2 with a thickness of 8 mm, and the outermost layer is mixture 3 with a thickness of 6 mm. The extruded material is cut into 10 mm long cylindrical pieces at the die head and immediately frozen at -20°C for 8 hours, then thawed for 4 hours, and then frozen again. This process is repeated three times to obtain the final product.

[0052] Example 4:

[0053] PVA particles were dissolved in deionized water at 80-95℃ with stirring to prepare a 10wt% PVA solution (embedding solution 1). The solution was cooled to room temperature and then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 1.

[0054] PVA particles were dissolved in deionized water at 80-95℃ with stirring to prepare a 2wt% PVA solution. The solution was then cooled to room temperature. Separately, PEG and xanthan gum were dissolved in deionized water with stirring at room temperature. The concentration of PEG in this solution was 10wt% and the concentration of xanthan gum was 0.05%. This solution was then mixed with the 2wt% PVA solution at a mass ratio of 1:2. The resulting mixture was then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 2.

[0055] PEG and xanthan gum were stirred and dissolved in deionized water at room temperature. The concentration of PEG in the solution was 10 wt%, and the concentration of xanthan gum was 0.1%. Then, it was mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 3.

[0056] In a three-layer co-extrusion unit containing three single-screw extruders, mixtures 1, 2, and 3 are extruded separately and compounded within a single-hole die head. The resulting extruded material is a three-layer structure with a diameter of 20 mm. The center layer is mixture 1 with a thickness of 10 mm, the middle layer is mixture 2 with a thickness of 6 mm, and the outermost layer is mixture 3 with a thickness of 4 mm. The extruded material is cut into 10 mm long cylindrical pieces at the die head and immediately frozen at -20°C for 8 hours, then thawed for 4 hours, and then frozen again. This process is repeated three times to obtain the final product.

[0057] Example 5:

[0058] PVA particles were dissolved in deionized water at 80-95℃ with stirring to prepare a 10wt% PVA solution (embedding solution 1). The solution was cooled to room temperature and then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 1.

[0059] PVA particles were dissolved in deionized water at 80-95℃ with stirring to prepare a 2wt% PVA solution. The solution was then cooled to room temperature. Separately, PEG and xanthan gum were dissolved in deionized water with stirring at room temperature. The concentration of PEG in this solution was 10wt% and the concentration of xanthan gum was 0.05%. This solution was then mixed with the 2wt% PVA solution at a mass ratio of 1:2. The resulting mixture was then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 2.

[0060] PEG and xanthan gum were stirred and dissolved in deionized water at room temperature. The concentration of PEG in the solution was 10 wt%, and the concentration of xanthan gum was 0.1%. Then, it was mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 3.

[0061] In a three-layer co-extrusion unit containing three single-screw extruders, mixtures 1, 2, and 3 are extruded separately and compounded within a single-hole die head. The resulting extruded material is a three-layer structure with a diameter of 20 mm. The center layer is mixture 1 with a thickness of 8 mm, the middle layer is mixture 2 with a thickness of 6 mm, and the outermost layer is mixture 3 with a thickness of 8 mm. The extruded material is cut into 10 mm long cylindrical pieces at the die head and immediately frozen at -20°C for 8 hours, then thawed for 4 hours, and then frozen again. This process is repeated three times to obtain the final product.

[0062] Comparative Example:

[0063] PVA particles were dissolved in deionized water under stirring at 80-95℃ to prepare a 10wt% PVA solution. The solution was cooled to room temperature and then mixed with calcium peroxide at a mass ratio of 1:1 to obtain mixture 1.

[0064] The mixture 1 is extruded through a single screw extruder at room temperature to obtain an extruded material strip with a diameter of 20 mm. The extruded material strip is cut into 10 mm long cylindrical objects at the die head and then immediately frozen at -20°C for 8 hours, then thawed for 4 hours, and then frozen again. This process is repeated 3 times to obtain the final product.

[0065] Experimental Results - Oxygen Release Experiments of Oxygen-Releasing Agents in Examples 1-5 and Comparative Examples:

[0066] Boil deionized water and pour it into a sealed container, ensuring the container is full. Then, purge the container with nitrogen gas for 10 minutes to remove any remaining dissolved oxygen. Insert a dissolved oxygen testing electrode into the container to monitor the dissolved oxygen (DO) value online. Weigh a certain amount of oxygen-releasing agent and add it to the container, then seal it. Monitor the change in DO over time online at room temperature and pressure. The oxygen release curve is shown below. Figure 1 The comparative example showed a significantly slower oxygen release rate in the initial stage of deployment, while the example showed a faster oxygen release rate in the initial stage of deployment and was able to maintain the oxygen release time for a long time.

[0067] The specific embodiments of the present invention have been described above, but the present invention is not limited thereto. Various changes can be made to the present invention as long as they do not depart from the spirit of the present invention.

Claims

1. A progressively disintegrating, slow-release oxygen composite material, characterized in that, It includes a three-layer structure: kernel layer, intermediate layer, and surface layer. The core layer is made of calcium peroxide and physically cross-linked PVA; The intermediate layer is made of calcium peroxide, water-soluble substances, and non-water-soluble substances. The non-water-soluble substances in the intermediate layer are physically cross-linked PVA. The water-soluble substances in the intermediate layer include water-soluble binders and tackifiers, wherein the water-soluble binder is polyethylene glycol and the tackifier is xanthan gum or sodium alginate. The surface material is calcium peroxide and a water-soluble substance. The water-soluble substance includes a water-soluble binder and a tackifier, wherein the water-soluble binder is polyethylene glycol and the tackifier is xanthan gum or sodium alginate.

2. The progressively disintegrating slow-release oxygen composite material according to claim 1, characterized in that, The core material contains 30-80 wt% calcium peroxide, and / or Its polyvinyl alcohol content is 20-70 wt%, and the degree of alcoholysis of polyvinyl alcohol is over 99%.

3. The progressively disintegrating slow-release oxygen composite material according to claim 1, characterized in that, The material of the intermediate layer comprises the following components: Calcium peroxide 30-80 wt% PVA 10-20wt%, PVA alcoholysis degree over 99%; Polyethylene glycol 0-20wt% Xanthan gum or sodium alginate 0-1wt%.

4. The progressively disintegrating slow-release oxygen composite material according to claim 1, characterized in that, The surface material comprises the following components: Calcium peroxide 40-80%; 20-60 wt% polyethylene glycol; Xanthan gum or sodium alginate 0-1wt%.

5. The progressively disintegrating slow-release oxygen composite material according to claim 1, characterized in that, The gradually disintegrating slow-release oxygen composite material is in the form of a columnar object with a diameter of 5-25 mm and a length of 10-20 mm. The core layer is 2-8mm thick, the intermediate layer is 5-10mm thick, and the surface layer is 2-10mm thick.

6. A method for preparing a progressively disintegrating, slow-release oxygen composite material, characterized in that, Includes the following steps: Core layer material preparation: PVA particles are dissolved in deionized water under stirring at 80-95℃. The mass concentration of the PVA aqueous solution is 5-20%. The completely dissolved PVA solution is cooled to room temperature and then cooled to 0-10℃ under refrigeration conditions. This solution is denoted as embedding solution 1. Calcium peroxide is added to embedding solution 1 and mechanically stirred until homogeneous. The stirring time is 5-20 min and the stirring speed is 100-300 rpm to obtain a flowable paste, denoted as mixture 1. Mixture 1 is extruded through a single screw extruder to obtain the core layer material. Preparation of intermediate layer material: PVA particles are dissolved in deionized water under stirring at 80-95℃, and the mass concentration of the PVA aqueous solution is 2-10%; polyethylene glycol, xanthan gum or sodium alginate are dissolved in deionized water under stirring at room temperature to form a mixed solution. This mixed solution is mixed with the PVA solution at room temperature in a certain proportion and is called embedding solution 2; calcium peroxide is added to embedding solution 2 and stirred evenly for 5-20 minutes at a stirring speed of 100-300 rpm to obtain a flowable paste, called mixture 2. Mixture 2 is extruded using a single screw extruder to prepare the intermediate layer material; Surface material preparation: Polyethylene glycol, xanthan gum, or sodium alginate are dissolved in deionized water at room temperature to obtain a mixed solution, denoted as embedding solution 3. Calcium peroxide is added to embedding solution 3 and stirred until homogeneous. The stirring time is 5-20 minutes and the stirring speed is 100-300 rpm to obtain a flowable paste, denoted as mixture 3. The surface material is prepared by extruding mixture 3 using a single-screw extruder. Material compounding: The core layer, intermediate layer and surface layer materials are compounded in a single-hole die head and extruded to obtain a three-layer extruded material strip with a diameter of 5-25mm. The center of the material strip is mixture 1, the intermediate layer is mixture 2 and the surface layer is mixture 3. The compound extrudate is cut at the extruder head to obtain a column with a length of 10-20mm. It is then immediately frozen at -20℃ for 8-12 hours, then thawed for 4 hours, and then frozen again. This process is repeated 2-4 times to obtain the final product.

7. The method for preparing the progressively disintegrating slow-release oxygen composite material according to claim 6, characterized in that, In the preparation of the core layer material, the PVA concentration is 8-10 wt%, and / or The completely dissolved PVA solution was cooled to 5°C under refrigeration conditions, and / or The mass ratio of calcium peroxide to embedding solution 1 is 1:1 to 1:

3.

8. The method for preparing the progressively disintegrating slow-release oxygen composite material according to claim 6, characterized in that, In the preparation of the intermediate layer material, the concentration of polyethylene glycol in the mixed solution is 2-15 wt%, the concentration of xanthan gum or sodium alginate is 0-2 wt%, and / or The mass ratio of the mixed solution to the PVA solution is 1:1 to 1:5; and / or The mass ratio of calcium peroxide to embedding solution 2 is 1:1 to 1:

3.

9. The method for preparing the progressively disintegrating slow-release oxygen composite material according to claim 6, characterized in that, In the preparation of the surface material, the concentration of polyethylene glycol in the mixed solution is 5-20 wt%, and the concentration of xanthan gum or sodium alginate is 0-2 wt%; and / or The mass ratio of calcium peroxide to embedding solution 3 is 1:1 to 1:3.

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