A method for preparing a porous bio-based atmospheric water enrichment material

Abstract

The application discloses a kind of porous biological base atmospheric enrichment water material preparation methods, comprising the following steps: (1) the preparation of hygroscopic salt solution;(2) the preparation of modified hainan mushroom;(3) the preparation of hygroscopic salt / modified hainan mushroom material.The beneficial effects of the present application are: (1) using the natural porous structure advantage of hainan mushroom, the modified porous biomass material is combined with hygroscopic salt, the moisture in the atmosphere can be adsorbed to the surface of the material by hygroscopic salt, then the moisture is transported to the inside of hainan mushroom, and is stored by the porous structure of oxygen-rich group, which can realize efficient enrichment of water vapor in the atmosphere.(2) The raw material of the porous biological base atmospheric enrichment water material of the present application is derived from natural hainan mushroom, hygroscopic salt, etc., which is a low-cost, green and efficient atmospheric water enrichment material.(3) The porous biological base atmospheric enrichment water material of the present application has good renewability and reusability, which can be used multiple times to reduce the consumption of natural resources.

Description

Technical Field

[0001] This invention relates to the field of functional composite materials technology, and in particular to a method for preparing porous bio-based atmospheric water enrichment materials. Background Technology

[0002] Atmospheric water-harvesting materials are materials capable of absorbing moisture from the atmosphere. They possess high water absorption capacity, allowing them to absorb water even in dry environments, forming hydrogels or liquid water. The importance of atmospheric water-harvesting materials lies in their ability to help collect and utilize atmospheric water resources, thereby addressing water scarcity issues. The applications of atmospheric water-harvesting materials are very broad, primarily including agriculture, environmental protection, medicine, and construction. In agriculture, they can be used for soil water retention, plant growth, and irrigation. In environmental protection, they can be used for wastewater treatment and air purification. In medicine, they can be used to prepare dressings and biomedical materials. In construction, they can be used to prepare waterproofing and insulation materials.

[0003] Atmospheric moisture exists primarily in the form of fog and water vapor, in addition to its existence as clouds and its collection through rainfall. Several different atmospheric water harvesting technologies have been developed based on these two forms, including: fog capture technology for moisture in fog form; cooling-based dew harvesting technology for moisture in water vapor form; and adsorption-based atmospheric water harvesting technology. A major challenge with fog harvesting is the requirement of 100% relative humidity (RH), which is limited by climate and geography. Dew harvesting technology requires cooling energy input to maintain the condensation temperature below the vapor dew point; when RH is below 40%, active refrigeration becomes extremely energy-intensive. Currently, some researchers have studied passive radiative cooling materials for enriching atmospheric water, but large-scale application research is limited. In contrast, atmospheric water enrichment materials using adsorbents to capture moisture are more energy-efficient and not limited by hydrological or geographical constraints. Hygroscopic salts are a low-cost but highly efficient desiccant. Under moderate relative humidity conditions, deliquescent salts such as CaCl2, LiCl, and LiBr can adsorb water molecules 1-3 times their own weight. These hygroscopic salts possess strong water absorption capabilities, making them ideal for moisture-related applications and thus attracting widespread attention in the field of water enrichment. However, a limiting drawback is that they eventually dissolve in the collected water, leading to reduced absorption kinetics, system corrosion, and difficulty in adsorbent recovery. To address this issue, the most popular strategy is to composite the hygroscopic salts into a designed matrix, where the loaded salt plays a major role in capturing water molecules, while the matrix acts as a container to hold the eventually liquefied salt. The water absorption performance of salt-based composites depends on the choice of salt, the loading content, and the matrix design. In recent years, extensive research has been conducted to develop functional matrices with better water-collecting performance. Reported matrix materials can be categorized into porous materials, hollow structural containers, fibrous matrices, and polymer networks. However, most matrix materials supporting hygroscopic salts suffer from drawbacks such as complex synthesis processes, high energy consumption, and non-degradability, negatively impacting the cost-effectiveness and ecological benefits of atmospheric water enrichment materials. Therefore, designing a low-cost, efficient, and eco-friendly substrate material is crucial for promoting the sustainable development of adsorption-based atmospheric water enrichment materials.

[0004] Most plants in nature (such as fungi) possess a naturally porous structure and excellent adsorption properties, making them easy to process into various shapes and sizes to meet diverse needs. These biomass porous materials are derived from low-cost natural biomass and, compared to fossil fuels, do not produce harmful gases such as carbon dioxide, making them more environmentally friendly. Furthermore, biomass porous materials can be made from recycled biomass, allowing for recycling and reducing dependence on natural resources. However, research on applying biomass porous materials to atmospheric water enrichment materials, while simultaneously enhancing the water vapor enrichment capacity of hygroscopic salts, is scarce. Therefore, the key problem this invention aims to solve is how to design a biomass porous matrix material and synergize the advantages of both the matrix material and hygroscopic salts to prepare novel, low-cost, green, and efficient atmospheric water enrichment materials. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing porous bio-based atmospheric water-enriching materials, so as to solve the problems existing in the preparation methods of atmospheric water-enriching materials in the prior art.

[0006] This invention provides a method for preparing porous bio-based atmospheric water enrichment materials, comprising the following steps:

[0007] (1) Preparation of hygroscopic salt solution: Dissolve hygroscopic salt in anhydrous ethanol solution to obtain a saturated hygroscopic salt solution at room temperature;

[0008] (2) Preparation of modified seafood mushrooms: Dried seafood mushrooms were placed in a NaOH solution with a concentration of 1-5 wt% at a bath ratio of 1:100 to 1:50 and boiled for 30-120 min. Then anhydrous ethanol and sodium chloroacetate were added to the solution, wherein the amount of anhydrous ethanol was 1:10 to 1:50 at a bath ratio of seafood mushrooms and the mass ratio of sodium chloroacetate to seafood mushrooms was 1:1. The mixture was kept at 71°C for 4 hours. After the reaction was completed, the mixture was filtered, the filter residue was dried and washed with deionized water to obtain fibrous pretreated seafood mushrooms.

[0009] Pretreated seafood mushrooms were dispersed in deionized water at a bath ratio of 1:20 to 1:100. Nitric acid and phosphoric acid were added to the solution at a volume ratio of 1 to 5:1, with a total acid concentration of 10 to 20 wt%. The reaction was carried out at room temperature for 3 to 5 hours. Sodium nitrite was then added to the solution at a concentration of 0.5 to 5 wt%, and the reaction was carried out at room temperature for 12 to 48 hours. After filtration, washing, and drying, modified seafood mushrooms with oxygen-rich groups were obtained.

[0010] (3) Preparation of moisture-absorbing salt / modified seafood mushroom material: The modified seafood mushroom was immersed in the moisture-absorbing salt solution according to the bath ratio, soaked for a certain period of time, taken out, and vacuum dried to obtain the moisture-absorbing salt / modified seafood mushroom material.

[0011] In the above-described method for preparing a porous bio-based atmospheric water-enriching material, preferably, the hygroscopic salt is 1 to 5 parts by weight, and the modified seafood mushroom is 5 to 10 parts by weight.

[0012] In the above-described method for preparing a porous bio-based atmospheric water-enriching material, preferably, the hygroscopic salt is lithium chloride, potassium acetate, magnesium chloride, potassium carbonate, magnesium nitrate, ammonium nitrate, sodium chloride, potassium chloride, potassium nitrate, or potassium sulfate.

[0013] The method for preparing a porous bio-based atmospheric water-enriching material as described above, wherein preferably, the bath ratio in step (3) is 1:50-100, the impregnation time is 5-10 h, the vacuum drying temperature is 75 ℃, and the drying time is 2 h.

[0014] In the above-described method for preparing a porous bio-based atmospheric water enrichment material, preferably, the seafood mushroom is a seafood mushroom with a growth cycle of 110 to 120 days.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) Taking advantage of the natural porous structure of seafood mushrooms, the modified porous biomass material is combined with hygroscopic salt. The hygroscopic salt can adsorb moisture in the atmosphere onto the surface of the material, and then the moisture is transported into the interior of the seafood mushroom and stored by the porous structure rich in oxygen groups, which can achieve efficient enrichment of water vapor in the atmosphere.

[0017] (2) The porous bio-based atmospheric water-enriching material of the present invention is derived from natural seafood mushrooms, hygroscopic salts, etc. It has low preparation cost, simple synthesis process, green and environmentally friendly, and degradable. It is a low-cost, green and efficient atmospheric water-enriching material.

[0018] (3) The porous bio-based atmospheric water-enriching material of the present invention has good renewability and reusability, allowing for multiple uses and reducing the consumption of natural resources. Hygroscopic salts can also be regenerated and recycled, reducing environmental pollution. The porous bio-based atmospheric water-enriching material can improve the sustainability of atmospheric water enrichment, realize the recycling of resources, protect the environment, and promote sustainable development. Attached Figure Description

[0019] Figure 1 This is the infrared spectrum of the modified seafood mushroom of the present invention;

[0020] Figure 2 This is a magnified scanning electron microscope image of a portion of the cross-section of the modified seafood mushroom of the present invention;

[0021] Figure 3 This is a magnified scanning electron microscope image of a portion of the longitudinal section of the modified seafood mushroom of the present invention;

[0022] Figure 4 This is a magnified scanning electron microscope image of a cross-section of the moisture-absorbing salt / modified seafood mushroom in Embodiment 1 of the present invention;

[0023] Figure 5 This is a magnified scanning electron microscope image of a longitudinal section of the moisture-absorbing salt / modified seafood mushroom in Embodiment 1 of the present invention;

[0024] Figure 6 This is a graph showing the water enrichment performance of the hygroscopic salt / modified seafood mushroom in Embodiment 1 of the present invention. Detailed Implementation

[0025] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] This invention provides a method for preparing porous bio-based atmospheric water enrichment materials, comprising the following steps:

[0027] (1) Preparation of hygroscopic salt solution: Dissolve hygroscopic salt in anhydrous ethanol solution to obtain a saturated hygroscopic salt solution at room temperature. The weight of hygroscopic salt is 1 to 5 parts. In the examples provided in this application, the hygroscopic salt is lithium chloride, potassium acetate, magnesium chloride, potassium carbonate, magnesium nitrate, ammonium nitrate, sodium chloride, potassium chloride, potassium nitrate, or potassium sulfate.

[0028] (2) Preparation of modified seafood mushrooms: The weight of modified seafood mushrooms is 5 to 10 parts. The dried seafood mushrooms are placed in a 1 to 5 wt% NaOH solution at a bath ratio of 1:100 to 1:50 and boiled for 30 to 120 minutes. Then anhydrous ethanol and sodium chloroacetate are added to the solution. The amount of anhydrous ethanol is 1:10 to 1:50 according to the seafood mushroom bath ratio, and the mass ratio of sodium chloroacetate to seafood mushrooms is 1:1. The mixture is kept at 71°C for 4 hours. After the reaction is completed, the mixture is filtered and the filter residue is dried. The dried seafood mushrooms were washed with deionized water to obtain fibrous pretreated seafood mushrooms. The pretreated seafood mushrooms were dispersed in deionized water at a bath ratio of 1:20 to 1:100. Nitric acid and phosphoric acid were added to the solution at a volume ratio of 1 to 5:1, with a total acid concentration of 10 to 20 wt%. The mixture was reacted at room temperature for 3 to 5 hours. Sodium nitrite was then added to the solution at a concentration of 0.5 to 5 wt%, and the mixture was reacted at room temperature for 12 to 48 hours. After filtration, washing, and drying, modified seafood mushrooms with oxygen-rich groups were obtained. In the embodiments provided in this application, the seafood mushrooms are those with a growth cycle of 110 to 120 days.

[0029] (3) Preparation of moisture-absorbing salt / modified seafood mushroom material: The modified seafood mushroom is immersed in the moisture-absorbing salt solution according to the bath ratio, soaked for a certain period of time, taken out, and vacuum dried to obtain the moisture-absorbing salt / modified seafood mushroom material. In the embodiments provided in this application, the bath ratio is 1:50 to 100, the soaking time is 5 to 10 h, the vacuum drying temperature is 75 ℃, and the drying time is 2 h.

[0030] Reference Figure 1 As shown, curve G is the infrared spectrum of the modified seafood mushroom, and curve T is the infrared spectrum of the natural seafood mushroom. The infrared spectra show that the natural seafood mushroom contains peaks of cellulose macromolecular chains, indicating that it includes cellulose in its composition. The cellulose macromolecules of the natural seafood mushroom have a peak structure at 1645 cm⁻¹. -1 The vibrational peaks characteristic of adsorbed water are quite prominent in the vicinity, indicating that the natural porous structure endows it with a certain water storage capacity. It is worth noting that the natural seafood mushroom exhibits a water storage capacity at 1735 cm⁻¹. -1 The presence of a weak carbonyl vibration peak is likely due to the presence of carboxyl groups in the cellulose macromolecules of natural seafood mushrooms, further confirming their excellent water adsorption capacity. Figure 1 The results showed that the modified seafood mushroom was at 1735 cm. -1 A distinct C=O stretching vibration absorption band appeared at 1645 cm⁻¹, with a relatively strong peak intensity, indicating the presence of numerous oxygen-rich carboxyl groups in the cellulose macromolecules of the modified seafood mushroom. Simultaneously, the overall peak shape of the modified seafood mushroom did not change significantly, indicating that the carbon skeleton of the cellulose was preserved and its structure remained intact, which is beneficial for maintaining the stability and mechanical properties of the porous structure. This invention introduces a large number of carboxyl groups into the porous structure of seafood mushrooms through oxidative modification, enhancing its hydrophilicity and improving its water storage capacity. Furthermore, a comparison of the infrared spectra of natural and modified seafood mushrooms shows that the modified seafood mushroom exhibits a stronger absorption band at 1645 cm⁻¹. -1 The absorption peak intensity was also significantly higher than that of natural seafood mushrooms, indicating that the modified seafood mushrooms had increased water adsorption in their cellulose macromolecules, which further confirms the strong water-binding capacity of the modified seafood mushrooms.

[0031] Reference Figure 2 As shown, the modified seafood mushroom has a natural three-dimensional porous structure formed by the cross-linking of cellulose macromolecular chains, which provides a great structural advantage for storing atmospheric water absorbed by hygroscopic salts.

[0032] Reference Figure 3As shown, the modified seafood mushroom has a certain orientation structure inside, indicating that the cellulose macromolecules of the seafood mushroom form a connected pore structure inside. This provides a channel for the transport of atmospheric water adsorbed by hygroscopic salt inside the seafood mushroom, reducing mass transfer obstacles. This will help the hygroscopic salt / modified seafood mushroom material to achieve efficient atmospheric water enrichment.

[0033] The following examples further illustrate the content of the present invention. Those skilled in the art will understand that more preparation methods can be designed based on the following examples, all of which fall within the protection scope of the present invention.

[0034] Example 1

[0035] A certain mass of lithium chloride was weighed and dissolved in anhydrous ethanol solution to obtain a saturated hygroscopic salt solution at room temperature. Modified seafood mushrooms were immersed in the hygroscopic salt solution at a bath ratio of 1:80 for 8 hours. After immersion, the mushrooms were removed and vacuum dried at 75 °C for 2 hours to obtain the hygroscopic salt / modified seafood mushroom material. The modified seafood mushrooms used in this embodiment were prepared according to the method provided in this application.

[0036] Reference Figure 4 As shown, the hygroscopic salt is firmly and uniformly loaded on the surface of the cellulose macromolecules of the modified seafood mushroom. The porous material has a large specific surface area and porosity, which can increase the contact area and adsorption capacity of the hygroscopic salt, thereby improving the efficiency of atmospheric water enrichment. At the same time, the combined use of biomass porous materials and hygroscopic salt allows the porous material to store the water adsorbed by the hygroscopic salt, further enhancing the hygroscopic performance of the hygroscopic salt and improving the collection efficiency of atmospheric water enrichment.

[0037] Reference Figure 5 As shown, the hygroscopic salt is firmly and evenly loaded inside the modified seafood mushroom. The porous structure of the modified seafood mushroom serves as a matrix to support the hygroscopic salt, preventing it from deliquescing and being lost after absorbing moisture.

[0038] Reference Figure 6 As shown, in an atmosphere with an air humidity (RH) of 30%, the water enrichment capacity of the hygroscopic salt / modified seafood mushroom continuously increases with increasing adsorption time, reaching a maximum of 0.5 g / g, and reaching equilibrium after 50 min of adsorption. The water enrichment capacity of this porous bio-based atmospheric water-enriching material is significantly higher than the values ​​reported in the literature (Fuel Process. Technol. 2002, 79 (3), 225). 231., Adv. Mater. 2020, 32 (39), 2002936.), which further confirms its efficient atmospheric water enrichment capacity.

[0039] Example 2

[0040] A certain mass of lithium bromide was weighed and dissolved in anhydrous ethanol solution to obtain a saturated hygroscopic salt solution at room temperature. Modified seafood mushrooms were immersed in the hygroscopic salt solution at a bath ratio of 1:80 for 8 hours. After immersion, the mushrooms were removed and vacuum dried at 75 °C for 2 hours to obtain the hygroscopic salt / modified seafood mushroom material. The modified seafood mushrooms used in this embodiment were prepared according to the method provided in this application.

[0041] Example 3

[0042] A certain mass of calcium chloride was weighed and dissolved in anhydrous ethanol solution to obtain a saturated hygroscopic salt solution at room temperature. Modified seafood mushrooms were immersed in the hygroscopic salt solution at a bath ratio of 1:80 for 8 hours. After immersion, the mushrooms were removed and vacuum dried at 75 °C for 2 hours to obtain the hygroscopic salt / modified seafood mushroom material. The modified seafood mushrooms used in this embodiment were prepared according to the method provided in this application.

[0043] The above description, based on the embodiments shown in the figures, details the structure, features, and effects of the present invention. The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, that do not exceed the spirit covered by the specification and figures, should be within the protection scope of the present invention.

Claims

1. A method for preparing porous bio-based atmospheric water enrichment materials, characterized in that, Includes the following steps: (1) Preparation of hygroscopic salt solution: Dissolve hygroscopic salt in anhydrous ethanol solution to obtain a saturated hygroscopic salt solution at room temperature; (2) Preparation of modified seafood mushrooms: Dried seafood mushrooms were placed in a NaOH solution with a concentration of 1-5 wt% at a bath ratio of 1:100 to 1:50 and boiled for 30-120 min. Then anhydrous ethanol and sodium chloroacetate were added to the solution, wherein the amount of anhydrous ethanol was 1:10 to 1:50 at a bath ratio of seafood mushrooms and the mass ratio of sodium chloroacetate to seafood mushrooms was 1:

1. The mixture was kept at 71°C for 4 hours. After the reaction was completed, the mixture was filtered, the filter residue was dried and washed with deionized water to obtain fibrous pretreated seafood mushrooms. Pretreated seafood mushrooms were dispersed in deionized water at a bath ratio of 1:20 to 1:

100. Nitric acid and phosphoric acid were added to the solution at a volume ratio of 1 to 5:1, with a total acid concentration of 10 to 20 wt%. The reaction was carried out at room temperature for 3 to 5 hours. Sodium nitrite was then added to the solution at a concentration of 0.5 to 5 wt%, and the reaction was carried out at room temperature for 12 to 48 hours. After filtration, washing, and drying, modified seafood mushrooms with oxygen-rich groups were obtained. (3) Preparation of moisture-absorbing salt / modified seafood mushroom material: The modified seafood mushroom was immersed in the moisture-absorbing salt solution according to the bath ratio, soaked for a certain period of time, taken out, and vacuum dried to obtain the moisture-absorbing salt / modified seafood mushroom material.

2. The method for preparing porous bio-based atmospheric water enrichment material according to claim 1, characterized in that, The moisture-absorbing salt is present in 1 to 5 parts by weight, and the modified seafood mushroom is present in 5 to 10 parts by weight.

3. The method for preparing porous bio-based atmospheric water enrichment material according to claim 1, characterized in that, The hygroscopic salt is lithium chloride, potassium acetate, magnesium chloride, potassium carbonate, magnesium nitrate, ammonium nitrate, sodium chloride, potassium chloride, potassium nitrate, or potassium sulfate.

4. The method for preparing porous bio-based atmospheric water enrichment material according to claim 1, characterized in that, The bath ratio in step (3) is 1:50 to 100, the soaking time is 5 to 10 h, the vacuum drying temperature is 75 ℃, and the drying time is 2 h.

5. The method for preparing porous bio-based atmospheric water enrichment material according to claim 1, characterized in that, The seafood mushrooms mentioned are those with a growth cycle of 110 to 120 days.

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