Indium-containing water-absorbing gel for promoting plant growth and preparation method thereof

Abstract

An indium-containing water-absorbing gel for promoting plant growth and a preparation method thereof. The method comprises: providing ethanol and adding indium trichloride to fully dissolve it; then adding ethanolamine to form a precursor solution; and thoroughly mixing the precursor solution with deionized water and drying it to obtain the water-absorbing gel. The indium-containing water-absorbing gel of the present invention has strong water absorption and good cyclic stability. It absorbs water at low temperatures and releases water at high temperatures, making it particularly suitable for promoting plant growth in arid areas.

Description

Technical Field

[0001] The invention relates to a water-absorbing gel for providing moisture for plant growth. Background Art

[0002] The supply of water required for plant growth has always been a problem, especially in arid areas where traditional liquid water irrigation is not suitable. Therefore, there has always been a need to effectively convert water from the atmosphere into a water source for plant growth. Summary of the Invention

[0003] The object of the present invention is to provide a water-absorbing gel which can effectively promote plant growth, especially in arid areas.

[0004] According to a first aspect of the present invention, there is provided a method for preparing a water-absorbing gel for promoting plant growth, comprising:

[0005] Provide ethanol and add indium trichloride to fully dissolve it;

[0006] Then, ethanolamine is added to form a precursor solution, wherein the content of indium trichloride is 5-7 mol / L and the content of ethanolamine is 40-45 mL / L; and

[0007] The precursor solution and deionized water are fully mixed and dried to obtain the water-absorbing gel, wherein the volume ratio of the precursor solution to the deionized water is 1:2 to 2:1, and the drying temperature is 40° C. to 80° C.

[0008] The present invention firstly forms weak coordination between metal ions and hydroxyl groups in ethanol, so that all metal ions are in a weak coordination equilibrium state. Then, ethanolamine is added to replace some of the originally coordinated hydroxyl groups with amino groups, thereby forming a compound with amino / metal / hydroxyl multi-component co-coordination.

[0009] Before adding water and drying, only the initial gel precursor forms, a coordination compound in equilibrium. Adding water changes the environment of the entire system, causing some metal ions to aggregate, forming tiny crystal structures measuring several nanometers, for example, approximately 5 nanometers. Adding water and then drying disperses the coordination compound, causing the hydrogel's structure to reorganize, forming a porous structure that enhances the hydrogel's water absorption capacity.

[0010] According to the preparation method of the present invention, the precursor solution and deionized water are preferably mixed and then placed in a (wide-mouthed) dish for drying until the ethanol solvent and water are completely evaporated.

[0011] According to the preparation method of the present invention, the content of indium trichloride in the precursor solution is preferably 6 mol / L, and the content of ethanolamine is preferably 42 mL / L. The content ratio of indium trichloride to ethanolamine in the present invention has an important influence on the water absorption capacity.

[0012] According to the preparation method of the present invention, the volume ratio of the precursor solution to deionized water is preferably 1:1, and the drying temperature is preferably 45° C. to 55° C., more preferably 50° C. Too high a drying temperature will destroy the structure of the hydrogel, while too low a drying temperature will result in incomplete dehydration of the hydrogel.

[0013] According to another aspect of the present invention, a water-absorbing gel for promoting plant growth is provided, which is prepared by the above method.

[0014] According to another aspect of the present invention, there is also provided a method for promoting plant growth, comprising:

[0015] Placing the water-absorbing gel in a sealable farm with soil plants;

[0016] Keep the farm closed in the morning to release moisture into the farm soil after the water-absorbing gel is heated by sunlight;

[0017] The farm was left open in the evening to allow the water-absorbing gel to absorb moisture from the surrounding environment.

[0018] According to a preferred embodiment of the present invention, the enclosed farm can be constructed as a transparent plastic greenhouse. This greenhouse is open at night to allow the gel to absorb water; it is closed during the day, allowing sunlight to dehydrate the gel and increase the relative humidity within the greenhouse. In actual use, the water-absorbing gel is preferably distributed around the perimeter of the greenhouse, such as by painting. This not only improves water distribution but also separates it from the soil to prevent soil contamination.

[0019] The indium-containing gel of the present invention has strong water absorption and excellent cyclic stability. It absorbs water at low temperatures and releases it at high temperatures, making it particularly suitable for promoting plant growth. Application of the gel of the present invention significantly reduces the amount of liquid water required for irrigation, making plant growth no longer restricted by water scarcity, even in arid and desert regions.

[0020] The invention frees crop cultivation from the complex water supply chain, significantly reducing costs and offering significant ecological advantages, particularly in arid regions. Furthermore, the entire process is solar-powered, requiring no additional energy input. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of photographs of the water-absorbing gel prepared according to the present invention in a dry state and after absorbing water in the environment for different time periods.

[0022] Figure 2 The XRD comparison diagrams of dry and wet water-absorbing gels.

[0023] Figure 3 These are graphs showing the water absorption mass of different amounts of gel in the environment.

[0024] Figure 4This is the dehydration curve of the gel under sunlight of different light intensities.

[0025] Figure 5 The graph shows the weight change of the gel during each adsorption and desorption cycle.

[0026] Figure 6 Comparison photos of the simulated farm's initial state and after the water-absorbing gel was placed and exposed to light for one hour.

[0027] Figure 7 A diagram showing the growth of plants in a simulated farm with and without gel applied.

[0028] Figure 8 This is a comparison chart of the element content of water released after the gel absorbs water in a simulated farm and is heated, compared with the World Health Organization standard drinking water. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the embodiments and drawings. Those skilled in the art should understand that the embodiments and drawings are only for better understanding of the present invention and are not intended to limit the present invention in any way.

[0030] Preparation of Indium-Containing Water-Absorbing Gel

[0031] Add 0.15 mol of InCl3 to 25 ml of ethanol solvent and dissolve it by ultrasonication to form a solution;

[0032] Then, 1050 μl of ethanolamine was added to the above solution and ultrasonicated to obtain a precursor solution;

[0033] After the precursor liquid and an equal amount of deionized water are fully mixed, the mixed solution is evenly covered on a wide-mouth dish and dried at 50° C. for 20 minutes to prepare an indium-containing water-absorbing gel for use.

[0034] Water-absorbing gel performance analysis / testing

[0035] Figure 1 Schematic diagram of the prepared water-absorbing gel in a dry state and after absorbing water for different time periods in an environment (80% relative humidity and 25 degrees Celsius). Figure 1 It can be seen that the dried water-absorbing gel is transparent at first, but gradually becomes turbid and a white solid is generated as the water absorption time passes.

[0036] Figure 2 The XRD comparison diagram of the dry and wet water-absorbing gel is shown in Figure 2. The gel is exposed to air for 24 hours to obtain the XRD analysis diagram of the wet state; the gel is heated and dried to obtain the XRD analysis diagram of the dry state. Figure 2It can be seen that both states have low crystallinity. The peak at 14.93° disappears after the gel absorbs water, indicating that the structure of the gel is destroyed after absorbing water.

[0037] Figure 3 The water absorption mass diagram of 0.1g, 0.15g and 0.2g of the above-prepared (after drying) indium-containing water-absorbing gel film in an environment (80% relative humidity and 25 degrees Celsius) is shown. Figure 3 It can be seen that as the amount of gel increases, the amount of water it can absorb also increases.

[0038] Figure 4 The figure is a dehydration curve of the indium-containing water-absorbing gel under sunlight of different light intensities, wherein 0.2g of the indium water-absorbing gel prepared above was taken to absorb water in the environment for 24 hours. Figure 4 It can be seen that the dehydration quality of the gel increases with the increase of light intensity. Under the irradiation of one sun, the gel can be dehydrated by about 80% in 90 minutes.

[0039] Figure 5 The graph shows the weight change of 0.5g of indium-containing water-absorbing gel prepared above during each adsorption and desorption cycle. Figure 5 It can be seen that the gel can maintain stability after continuous water absorption and dehydration.

[0040] Simulated farm plant growth promotion experiment

[0041] The prepared water-absorbing gel was placed in a dish and secured to the upper half of a closed transparent box. The box, measuring 10 cm x 10 cm x 20 cm, contained 5 g of the indium-containing water-absorbing gel. Soil was placed at the bottom of the box, and mung bean seeds were randomly placed in the soil. This closed box can be called a simulated farm. In this simulated farm, water release from the gel is triggered by solar radiation. The released water vapor is trapped within the closed box, condenses, and falls into the soil for irrigation. Water absorption occurs when the box is opened at night in the humid environment.

[0042] Figure 6 The following is a comparison of the initial state of the simulated farm and the one-hour exposure to light after the water-absorbing gel was placed there. Figure 6 It can be clearly seen that after the gel is placed in the simulated farm and exposed to light for one hour, the gel releases a large amount of water, attaches to the container wall, and continuously flows into the soil. It continues to absorb water at night until it reaches saturation, absorbing approximately 15g of water per day.

[0043] Figure 7This figure shows plant growth in simulated farms with and without gel application, using soil dried at 40°C as an example. Every day at 10:00 AM, the simulated farm's lid was closed and placed outdoors in sunlight. At 6:00 PM, the lid was opened to allow the gel to absorb moisture in the humid night air. After repeating this process for eight days, the plants reached a height of 8 cm. In a control simulated farm under identical conditions without gel application, plants showed little growth. This demonstrates that the plants in the simulated farm with gel application were continuously irrigated and therefore thrived.

[0044] Figure 8 This is a comparison chart of the element content of the water released (collected) after the gel absorbs water in a simulated farm and is compared with the World Health Organization standard drinking water. Figure 8 It can be seen that the content of all elements in the water released by the gel is lower than the limit of the World Health Organization's standard drinking water, which shows that the water collected by the gel can be safely used for plant growth.

[0045] The water absorption mechanism of the present invention can be explained as follows: the surface of the hydrogel particles first combines with water molecules to form a monolayer chemical adsorption, 200kJ mol -1 The adsorption distance is small (<1nm), which is not easy to desorb, but it can fix the binding direction of water molecules; then multilayer physical adsorption is carried out under the action of adsorbed water hydroxyl groups, 20kJ mol -1 The adsorption distance is large (<100nm), the desorption energy consumption is low, and the adsorption / desorption rate is fast. Theoretically, the total number of water molecules captured by the coordination compound composed of a single metal ion can reach more than 50.

Claims

1. A method for promoting plant growth, comprising: The water-absorbing gel is placed in an enclosed farm with soil plants, wherein the enclosed farm is in the form of a transparent plastic greenhouse and the water-absorbing gel is spread around the inner periphery of the greenhouse; Keep the farm closed in the morning to release moisture into the farm soil after the water-absorbing gel is heated by sunlight; Leave the farm open in the evening to allow the water-absorbing gel to absorb moisture from the surrounding environment. The preparation method of the water-absorbing gel comprises: Provide ethanol and add indium trichloride to fully dissolve it; Then, ethanolamine is added to form a precursor solution, wherein the content of indium trichloride is 5-7 mol / L and the content of ethanolamine is 40-45 mL / L; and The precursor solution and deionized water are fully mixed and dried to obtain the water-absorbing gel, wherein the volume ratio of the precursor solution to the deionized water is 1:2 to 2:1, and the drying temperature is 40° C. to 80° C.

2. The method according to claim 1, wherein the precursor solution and deionized water are mixed and then placed in a dish for drying until the ethanol solvent and water are completely evaporated.

3. The method according to claim 1, wherein the content of indium trichloride in the precursor solution is 6 mol / L, and the content of ethanolamine is 42 mL / L.

4. The method according to claim 1, wherein the volume ratio of the precursor solution to deionized water is 1:1, and the drying temperature is 50°C.

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