Preparation method and application of low-cost water and fertilizer slow-release functional hydrogel

Abstract

The invention relates to a preparation method and application of low-cost water and fertilizer slow-release functional hydrogel, and belongs to the technical field of new environment-friendly materials.The preparation method comprises the steps that polyacrylonitrile-containing acrylic old clothes and animal bones are smashed, then subjected to compression molding, pre-oxidized in an air atmosphere and finally subjected to a hydrothermal reaction, and the low-cost hydrogel is obtained. The prepared low-cost hydrogel is high in water content, durable in water retention, rich in nitrogen, phosphorus, potassium and other elements necessary for plant growth, long in water and fertilizer slow release time and used for desert control and greening. According to the method, waste such as old clothes and waste bones which are difficult to degrade in the natural environment is prepared into the hydrogel material suitable for plant growth, and the hydrogel material is used for desert greening and desertification control, has economic significance and environmental significance and is relatively feasible.

Description

Technical Field

[0001] This invention belongs to the field of environmental science and technology, specifically relating to a method for preparing and using a low-cost water-fertilizer slow-release hydrogel. Background Technology

[0002] Desertification is a serious ecological problem on Earth, with far-reaching and alarming consequences. It leads to large-scale land degradation, reducing the area of ​​land available for agriculture, animal husbandry, and habitation. Afforestation and grassland planting are effective ways to combat desertification, but these efforts face numerous challenges. Harsh climatic conditions, such as high temperatures, drought, and strong winds, threaten tree growth, making it difficult for them to survive in such environments. Water resources are typically very limited in desert regions, increasing the difficulty of afforestation, as trees require large amounts of water to grow, while water supply is scarce. Poor soil quality, infertile and lacking nutrients, necessitates soil improvement and fertilization. Strong winds and sand erosion are another challenge, potentially damaging trees and vegetation, thus requiring appropriate wind and sand control measures. With economic and social development, needs in areas such as clothing, food, housing, and transportation have been largely met. For example, millions of tons of old clothes are essentially disposed of through landfills or incineration, and current technology lacks effective methods for utilizing these old garments. Acrylic fiber, one of the three major synthetic fibers (the other two being polyester and nylon), is primarily composed of polyacrylonitrile. Its production volume is enormous, and this polymer is difficult to biodegrade naturally, making recycling a persistent challenge with current technologies. With rising living standards, meat consumption is increasing. Bones, primarily composed of hydroxyapatite ceramics, are also difficult to degrade naturally. Hydrogels are porous materials with a network of water-filled nanopores, typically soft, hydrophilic polymers. Common examples include tofu, jelly, and mung bean jelly. Due to their unique three-dimensional porous structure and excellent water absorption capacity, hydrogels have broad application potential in tissue engineering, agricultural production, drug delivery, pollutant adsorption and treatment, and biosensors. However, as a novel functional material, hydrogels are relatively expensive and unsuitable for desertification control. Summary of the Invention

[0009] The present invention addresses the problems mentioned in the background art by disclosing a low-cost method for preparing a water-fertilizer slow-release functional hydrogel and its applications. The specific steps of the preparation method disclosed in this invention include: Step 1, crushing animal bones and old acrylic clothing into powder and mixing them evenly; Step 2, hot-pressing the sample at 180℃~250℃ and 30MPa; Step 3, pre-oxidizing the hot-pressed sample in an air atmosphere at 200℃~300℃ for 2~12h; Step 4, adding water to the pre-oxidized sample and placing it in a sealed high-pressure device, treating it at 150℃~250℃ and 0.1~10MPa for 2~10h to obtain the low-cost water-fertilizer slow-release functional hydrogel material.

[0010] The present invention also provides an application of this low-cost hydrogel, namely, for desert greening and sand control.

[0011] Plants need nutrients such as nitrogen, phosphorus, and potassium to grow. Polyacrylonitrile is rich in nitrogen, and the main component of bones is hydroxyapatite, which provides nutrients such as nitrogen, phosphorus, and potassium.

[0012] Beneficial effects: This invention utilizes waste materials such as old clothing containing polyacrylonitrile and bones to prepare low-cost hydrogels for desert greening and remediation. It achieves dual environmental benefits: the prepared low-cost hydrogel locks in moisture while providing nutrients such as nitrogen, phosphorus, and potassium, thus contributing to desert greening and sand control. Attached Figure Description

[0013] Figure 1 Digital photograph of the hydrogel prepared in Example 1 Specific implementation methods

[0014] Example 1

[0015] Animal bones and old acrylic clothing were crushed into powder and mixed evenly. The sample was then hot-pressed at 180℃ and 30MPa. The hot-pressed sample was pre-oxidized in air at 200℃ for 12 hours. The pre-oxidized sample was then added with water and placed in a closed high-pressure device and treated at 150℃ and 0.1MPa for 10 hours to obtain a low-cost water-fertilizer slow-release hydrogel material. The prepared hydrogel is used for desert greening and remediation.

[0016] Example 2

[0017] Animal bones and old acrylic clothing were crushed into powder and mixed evenly. The sample was then hot-pressed at 200℃ and 30MPa. The hot-pressed sample was pre-oxidized in air at 220℃ for 5 hours. The pre-oxidized sample was then placed in a closed high-pressure device with water and treated at 200℃ and 1MPa for 8 hours to obtain a low-cost water-fertilizer slow-release hydrogel material. The prepared hydrogel is used for desert greening and management.

[0018] Example 3

[0019] Animal bones and old acrylic clothing were crushed into powder and mixed evenly. The sample was then hot-pressed at 250℃ and 30MPa. The hot-pressed sample was pre-oxidized in air at 300℃ for 2 hours. The pre-oxidized sample was then placed in a closed high-pressure device with water and treated at 250℃ and 10MPa for 2 hours to obtain a low-cost water-fertilizer slow-release hydrogel material. The prepared hydrogel is used for desert greening and remediation.

[0020] Example 4

[0021] Animal bones and waste polyacrylonitrile fibers were crushed into powder and mixed evenly. The sample was then hot-pressed at 250℃ and 30MPa. The hot-pressed sample was pre-oxidized in air at 200℃ for 12 hours. The pre-oxidized sample was then placed in a closed high-pressure device with water and treated at 220℃ and 2MPa for 4 hours to obtain a low-cost water-fertilizer slow-release hydrogel material. The prepared hydrogel is used for desert greening and management.

[0022] Example 5

[0023] Animal bones and polyacrylonitrile industrial waste plastics were crushed into powder and mixed evenly. The sample was then hot-pressed at 250℃ and 30MPa. The hot-pressed sample was pre-oxidized in air at 200℃ for 12 hours. The pre-oxidized sample was then added with water and placed in a closed high-pressure device and treated at 220℃ and 2MPa for 4 hours to obtain a low-cost water-fertilizer slow-release hydrogel material. The prepared hydrogel is used for desert greening and remediation.

Claims

1. A method for preparing a low-cost water-fertilizer slow-release functional hydrogel, characterized by the following steps: Step 1, crushing animal bones and old acrylic clothing into powder and mixing them evenly; Step 2, pressing the sample into shape; Step 3, pre-oxidizing the hot-pressed sample in an air atmosphere; Step 4, adding water to the pre-oxidized sample and placing it in a closed high-pressure device, and subjecting it to hydrothermal treatment to obtain a low-cost water-fertilizer slow-release functional hydrogel material.

2. According to claim 1, a method for preparing a low-cost water-fertilizer slow-release hydrogel, wherein the hot pressing pressure is 30 MPa and the temperature is 180℃~250℃.

3. According to claim 1, a method for preparing a low-cost water-fertilizer slow-release functional hydrogel, wherein the pre-oxidation temperature is 200℃~300℃ and the time is 2~12h.

4. According to claim 1, a method for preparing a low-cost water-fertilizer slow-release functional hydrogel, wherein the hydrothermal treatment temperature is 150℃~250℃ and the pressure is 0.1~10Mpa for 2~10h.

5. According to claim 1, a method for preparing a low-cost water-fertilizer slow-release hydrogel is used for desert greening and management.

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