Novel polylysine / vermiculite composite aerogel material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of formaldehyde removal, in particular to a novel polylysine / vermiculite composite aerogel material as well as a preparation method and application thereof.Hydrogel formed through electrostatic interaction crosslinking between polylysine and vermiculite nanosheets can generate high-porosity aerogel with an open pore structure after freeze drying; and an orderly arranged lamellar structure is presented. Boron nitride is added, and the aerogel material is of a squamous lamellar structure, has the porous and loose characteristics and facilitates adsorption of formaldehyde. The aerogel can be used as an efficient adsorbent for directly capturing formaldehyde in air. Hydrogel is formed through electrostatic interaction crosslinking between polylysine and vermiculite nanosheets, boron nitride is added, and the hydrogel is of a squamous lamellar structure, has the porous and loose characteristics and facilitates adsorption of formaldehyde. Boron nitride can be used as a heat conduction agent, the heat conduction coefficient of the material is increased, desorption is rapid, meanwhile, boron nitride and vermiculite form a heterojunction, formaldehyde is decomposed through illumination, and the boron nitride and vermiculite become an ideal material for direct formaldehyde capture.

Description

Technical Field

[0001] The invention relates to the technical field of formaldehyde removal, and in particular to a novel polylysine / vermiculite composite aerogel material, a preparation method and an application thereof. Background Art

[0002] Formaldehyde (HCHO) is a colorless, volatile organic compound with a strong, pungent odor. It is a gas at room temperature and readily soluble in water. It is widely present in decoration materials and furniture adhesives. The World Health Organization classifies it as a Class 1 carcinogen. Long-term exposure can cause malignancies such as leukemia and nasopharyngeal cancer. Short-term exposure can irritate the respiratory tract and mucous membranes, leading to coughing, skin allergies, and eye irritation. It is particularly harmful to sensitive individuals such as children and pregnant women. Adsorption methods use physical or chemical interactions within porous materials to capture and immobilize formaldehyde molecules, reducing airborne formaldehyde concentrations. Aerogel, a nanoporous material (porosity >90% and surface area up to 1000 m² / g), efficiently captures and decomposes formaldehyde through its exceptionally strong adsorption capacity and chemical modification (such as titanium dioxide loading). However, adsorption materials like aerogel are difficult to quickly desorb and cannot be recycled. Furthermore, adsorption does not decompose formaldehyde. Therefore, a reusable material is urgently needed to improve the environmental friendliness and sustainability of formaldehyde removal materials. Summary of the Invention

[0003] The purpose of the present invention is to provide a novel polylysine / vermiculite composite aerogel material, a preparation method and an application thereof, and to obtain the most suitable polylysine loading amount and the maximum formaldehyde capture capacity through optimization.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing a novel polylysine / vermiculite composite aerogel material comprises the following steps:

[0006] The vermiculite powder is hydrothermally treated with a saturated sodium chloride solution to obtain modified vermiculite;

[0007] The modified vermiculite and lithium salt solution are subjected to a secondary hydrothermal treatment to obtain a modified vermiculite powder. The modified vermiculite powder is subjected to a shear exfoliation treatment, and the exfoliation product is subjected to gradient centrifugation to obtain a vermiculite nanosheet dispersion.

[0008] The vermiculite nanosheet dispersion and the polylysine aqueous solution are uniformly mixed and freeze-dried to obtain a polylysine-vermiculite composite aerogel material with a three-dimensional porous network structure.

[0009] As a further solution of the present invention: the usage ratio of vermiculite powder to saturated sodium chloride solution is (1.2-5.4) g: (1-200) mL.

[0010] As a further solution of the present invention: the dosage ratio of modified vermiculite to lithium salt solution is (1.2 - 5.4) g : (50 - 150) mL.

[0011] As a further solution of the present invention: the amount of substance of the vermiculite nanosheet dispersion is 1 - 10 mol / L.

[0012] As a further solution of the present invention: the mass ratio of the vermiculite nanosheet dispersion to polylysine is (1 - 100) mg : (1 - 100) mg.

[0013] As a further solution of the present invention: the mass ratio of the vermiculite nanosheet dispersion to boron nitride is (1 - 100) mg : (1 - 100) mg.

[0014] As a further solution of the present invention: the specific steps for gradient centrifugal separation of the exfoliated product are as follows:

[0015] First, remove the unexfoliated particles by low-speed centrifugation. After collecting the supernatant, perform high-speed centrifugation. The obtained precipitate is redispersed and adjusted to vermiculite nanosheet dispersions with different concentrations.

[0016] As a further solution of the present invention: the rotation speed of the low-speed centrifugation is 100 - 500 rpm / min, and the time of the low-speed centrifugation is 5 - 20 min;

[0017] The rotation speed of the high-speed centrifugation is 5000 - 6000 rpm / min, and the time of the high-speed centrifugation is 20 - 40 min.

[0018] A novel polylysine / vermiculite composite aerogel material, characterized in that the composite aerogel material is prepared by the above method, and the composite aerogel material is:

[0019] A hydrogel crosslinked by electrostatic interaction between polylysine and vermiculite nanosheets. After freeze-drying, a highly porous aerogel with an open pore structure is formed, presenting an orderly arranged lamellar structure. Adding boron nitride, it presents a scaly lamellar structure, has a porous and loose property, and is an aerogel material convenient for the adsorption of formaldehyde.

[0020] The application of a novel polylysine / vermiculite composite aerogel material, the application of the composite aerogel material prepared by the above method in removing formaldehyde.

[0021] The beneficial effects of the present invention:

[0022] The present invention provides a novel polylysine / vermiculite composite aerogel material, its preparation method and its application. A novel adsorbent, polylysine / vermiculite composite aerogel, with a simple, economical and environmentally friendly synthesis strategy is proposed for capturing formaldehyde from ambient air. Vermiculite nanosheets are a natural two-dimensional material with exposed surfaces and inherent negative charges. Among them, polylysine is used as a crosslinking agent to rapidly gelify the vermiculite nanosheet dispersion to form a hydrogel, which is then freeze-dried to produce the polylysine / vermiculite composite aerogel. By finely controlling the concentration of the vermiculite nanosheet dispersion and the loading amount of polylysine, we can precisely adjust the composition and microstructure of the resulting aerogel. The loading amount of polylysine has a significant impact on the pore structure and specific surface area of the aerogel, thus affecting the formaldehyde capture ability of the adsorbent. Through optimization, the most suitable polylysine loading amount and the maximum formaldehyde capture ability are obtained;

[0023] Through the electrostatic interaction between polylysine and vermiculite, a cross-linked network structure is formed, and after freeze-drying, an aerogel is formed, which has a porous structure and improves the adsorption of formaldehyde. Boron nitride is added to the aerogel, which can not only be used as a heat conductor to rapidly desorb at high temperatures for cyclic use, but also form a heterojunction material with vermiculite to photocatalytically decompose formaldehyde. This gel system can not only rapidly adsorb and desorb formaldehyde for rapid cyclic use, but also gradually decompose formaldehyde under light for applications in different scenarios. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 SEM images of the aerogels prepared for Examples 1-6;

[0026] Figure 2 Data graphs of the cyclic formaldehyde removal effects of the aerogels prepared for Examples 1-6.

[0027] Figure 3 Data graphs of the formaldehyde removal effects of the aerogels of Comparative Example 1 and Examples 1-6 in a low-humidity environment;

[0028] Figure 4 Data graphs of the formaldehyde removal effects of the aerogels of Comparative Example 1 and Examples 1-6 in a high-humidity environment. Detailed Embodiments

[0029] To enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solution in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] Example 1

[0031] A preparation method of a novel polylysine / vermiculite composite aerogel material provided by an embodiment of the present invention includes the following steps:

[0032] Step 1, prepare modified vermiculite:

[0033] Grind vermiculite particles and dry them at a temperature of 50 °C; Immerse 3.6 g of the dried vermiculite powder in 100 mL of saturated sodium chloride (NaCl) solution, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h; After cooling for 20 h to room temperature, filter it under vacuum and wash it with 500 mL of pure water until neutral to obtain the first filter residue. Dry the first filter residue in a drying oven at 50 °C for 24 h to obtain modified vermiculite;

[0034] Step 2, prepare a concentrated dispersion of vermiculite nanosheets:

[0035] Weigh 3.6 g of modified vermiculite and immerse it in 100 mL of a lithium chloride (LiCl) solution with a concentration of 2 mol / L, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h. After cooling for 20 h to room temperature, filter it under vacuum and wash it with 500 mL of pure water until neutral to obtain the second filter residue. Dry the second filter residue in a drying oven at 50 °C for 24 h;

[0036] Immerse 3.6 g of the dried second filter residue in 80 mL of ionized water and perform intermittent shear mixing at a speed of 20000 rpm / min for 10 min for delamination and exfoliation;

[0037] The suspension after delamination and exfoliation is centrifuged at a speed of 300 rpm / min for 1 hour, and the collected supernatant is the dispersion of vermiculite nanosheets (VNs). Then centrifuge it at a speed of 6000 rpm / min for 1 hour to concentrate it to a 5 mg / mL VNS dispersion;

[0038] Step 3, prepare polylysine-vermiculite composite aerogel

[0039] Mix 20 mL of a 5 mg / mL VNS dispersion with 1 mL of a 100 mg / mL polylysine aqueous solution, stir at room temperature, and sonicate in a water bath for 20 minutes; then add 10 mL of a 10 mg / mL boron nitride aqueous solution, stir at room temperature, sonicate in a water bath for 20 minutes, and perform low-temperature freeze curing for 3 hours; freeze-dry to obtain the polylysine-vermiculite composite aerogel;

[0040] The polylysine / vermiculite composite aerogel material is a hydrogel formed by cross-linking through electrostatic interaction between polylysine and vermiculite nanosheets (VNs). After freeze-drying, it will generate a highly porous aerogel with an open pore structure, presenting an orderly arranged lamellar structure. Adding boron nitride, it presents a scaly lamellar structure, has a porous and loose property, and is a composite aerogel material convenient for the adsorption of formaldehyde.

[0041] Example 2

[0042] A preparation method of a novel polylysine / vermiculite composite aerogel material provided by an embodiment of the present invention includes the following steps:

[0043] A preparation method of a novel polylysine / vermiculite composite aerogel material provided by an embodiment of the present invention includes the following steps:

[0044] Step 1, prepare modified vermiculite:

[0045] Grind vermiculite particles and dry them at a temperature of 50 °C; immerse 2.4 g of the dried vermiculite powder in 80 mL of a saturated sodium chloride (NaCl) solution, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h; after cooling to room temperature for 20 h, perform vacuum filtration and wash with 500 mL of pure water until neutral to obtain the first filter residue, and dry the first filter residue in a drying oven at 50 °C for 24 h to obtain modified vermiculite;

[0046] Step 2, prepare a concentrated dispersion of vermiculite nanosheets:

[0047] Weigh 2.4 g of modified vermiculite and immerse it in 100 mL of a 1 mol / L lithium chloride (LiCl) solution, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h. After cooling to room temperature for 20 h, perform vacuum filtration and wash with 500 mL of pure water until neutral to obtain the second filter residue, and dry the second filter residue in a drying oven at 50 °C for 24 h;

[0048] Immerse 2.4 g of the dried second filter residue in 80 mL of ionized water and perform intermittent shear mixing at a speed of 20000 rpm / min for 10 min for delamination and exfoliation;

[0049] The suspension after delamination was centrifuged at 300 rpm / min for 30 minutes, and the collected supernatant was the vermiculite nanosheet (VNs) dispersion. Then it was centrifuged at 5000 rpm / min for 30 minutes to concentrate it into a 10 mg / mL VNS dispersion;

[0050] Step 3, prepare polylysine-vermiculite composite aerogel

[0051] Mix 10 mL of 5 mg / mL VNS dispersion with 2 mL of 50 mg / mL polylysine aqueous solution, stir at room temperature, and ultrasonically treat in a water bath for 10 minutes; then add 5 mL of 10 mg / mL boron nitride aqueous solution, stir at room temperature, and ultrasonically treat in a water bath for 20 minutes, followed by low-temperature freeze curing for 3 hours; freeze-dry the obtained polylysine-vermiculite composite aerogel;

[0052] The polylysine / vermiculite composite aerogel material is a hydrogel formed by cross-linking through electrostatic interaction between polylysine and vermiculite nanosheets (VNs). After freeze-drying, it will generate a highly porous aerogel with an open pore structure, presenting an orderly arranged lamellar structure. Adding boron nitride, it presents a squamous lamellar structure with porous and loose characteristics, which is a composite aerogel material convenient for formaldehyde adsorption.

[0053] Example 3

[0054] A preparation method of a novel polylysine / vermiculite composite aerogel material provided by an embodiment of the present invention includes the following steps:

[0055] Step 1, prepare modified vermiculite:

[0056] Grind vermiculite particles and dry them at 50 °C; immerse 1.2 g of the dried vermiculite powder in 50 mL of saturated sodium chloride (NaCl) solution, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h; after cooling to room temperature for 20 h, vacuum filter and wash it with 500 mL of pure water until neutral to obtain the first filter residue, and dry the first filter residue in a drying oven at 50 °C for 24 h to obtain modified vermiculite;

[0057] Step 2, prepare a concentrated vermiculite nanosheet dispersion:

[0058] Weigh 1.2 g of modified vermiculite and immerse it in 80 mL of 1.5 mol / L lithium chloride (LiCl) solution, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for two hours. After cooling to room temperature for 20 h, vacuum filter and wash it with 500 mL of pure water until neutral to obtain the second filter residue, and dry the second filter residue in a drying oven at 50 °C for 24 h;

[0059] Immerse 1.2 g of the dried second filter residue in 80 mL of deionized water, and intermittently shear and mix at a speed of 20,000 rpm / min for 10 min for delamination and exfoliation;

[0060] The suspension after delamination and exfoliation is centrifuged at a speed of 300 rpm / min for 45 minutes. The collected supernatant is the vermiculite nanosheet (VNs) dispersion, and then it is centrifuged at a speed of 6000 rpm / min for 1 hour to concentrate it to a 10 mg / mL VNS dispersion;

[0061] Step 3, prepare polylysine-vermiculite composite aerogel

[0062] Mix 10 mL of a 10 mg / mL VNS dispersion with 0.5 mL of a 100 mg / mL polylysine aqueous solution, stir at room temperature, and ultrasonically treat in a water bath for 20 minutes; then add 5 mL of a 10 mg / mL boron nitride aqueous solution, stir at room temperature, and ultrasonically treat in a water bath for 20 minutes, and perform cryogenic freezing and curing for 3 hours; freeze-dry the obtained polylysine-vermiculite composite aerogel;

[0063] The polylysine / vermiculite composite aerogel material is a hydrogel crosslinked through electrostatic interaction between polylysine and vermiculite nanosheets (VNs). After freeze-drying, it will generate a highly porous aerogel with an open pore structure, presenting an orderly arranged lamellar structure. Adding boron nitride, it presents a scaly lamellar structure, has a porous and loose property, and is a composite aerogel material convenient for the adsorption of formaldehyde.

[0064] Example 4

[0065] A preparation method of a novel polylysine / vermiculite composite aerogel material provided by an embodiment of the present invention includes the following steps:

[0066] Step 1, prepare modified vermiculite:

[0067] Grind vermiculite particles and dry them at a temperature of 50°C; Immerse 3 g of the dried vermiculite powder in 90 mL of saturated sodium chloride (NaCl) solution, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110°C for 2 h; After cooling to room temperature for 20 h, perform vacuum filtration and wash it with 500 mL of pure water until neutral to obtain the first filter residue. Dry the first filter residue in a drying oven at 50°C for 24 h to obtain modified vermiculite;

[0068] Step 2, prepare a concentrated vermiculite nanosheet dispersion:

[0069] Weigh 3 g of modified vermiculite and immerse it in 100 mL of a lithium chloride (LiCl) solution with a concentration of 2.5 mol / L. After stirring it evenly, add it to a hydrothermal reaction kettle and react at 110 °C for 2 h. After cooling for 20 h to room temperature, perform vacuum filtration and wash it with 500 mL of pure water until neutral to obtain the second filter residue. Dry the second filter residue in a drying oven at 50 °C for 24 h;

[0070] Immerse 3 g of the dried second filter residue in 80 mL of ionized water and perform intermittent shear mixing at a speed of 13,000 rpm / min for 10 min for delamination and exfoliation;

[0071] The suspension after delamination and exfoliation is centrifuged at a rotational speed of 300 rpm / min for 45 minutes. The collected supernatant is the vermiculite nanosheet (VNs) dispersion. Then, centrifuge it at a rotational speed of 6,000 rpm / min for 1 h to concentrate it to a 10 mg / mL VNS dispersion;

[0072] Step 3, prepare polylysine-vermiculite composite aerogel

[0073] Mix 15 mL of a 5 mg / mL VNS dispersion with 0.4 mL of a 100 mg / mL polylysine aqueous solution, stir at room temperature, and perform ultrasonic treatment in a water bath for 20 minutes; then add 5 mL of a 5 mg / mL boron nitride aqueous solution, stir at room temperature, and perform ultrasonic treatment in a water bath for 20 minutes, and carry out low-temperature freeze curing for 3 h; freeze-dry the obtained polylysine-vermiculite composite aerogel.

[0074] The polylysine / vermiculite composite aerogel material is a hydrogel crosslinked through electrostatic interaction between polylysine and vermiculite nanosheets (VNs). After freeze-drying, it will generate a highly porous aerogel with an open pore structure, presenting an orderly arranged lamellar structure. Adding boron nitride, it presents a scaly lamellar structure, has a porous and loose property, and is a composite aerogel material convenient for the adsorption of formaldehyde.

[0075] Example 5

[0076] A preparation method of a novel polylysine / vermiculite composite aerogel material provided by an embodiment of the present invention includes the following steps:

[0077] Step 1, prepare modified vermiculite:

[0078] Grind vermiculite particles and dry them at a temperature of 50 °C; Immerse 2 g of the dried vermiculite powder in 120 mL of saturated sodium chloride (NaCl) solution, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h; After cooling for 20 h to room temperature, filter it under vacuum and wash it with 500 mL of pure water until neutral to obtain the first filter residue. Dry the first filter residue in a drying oven at 50 °C for 24 h to obtain modified vermiculite;

[0079] Step 2, prepare a concentrated dispersion of vermiculite nanosheets:

[0080] Weigh 2 g of modified vermiculite and immerse it in 100 mL of a lithium chloride (LiCl) solution with a concentration of 1 mol / L. Stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h. After cooling for 20 h to room temperature, filter it under vacuum and wash it with 500 mL of pure water until neutral to obtain the second filter residue. Dry the second filter residue in a drying oven at 50 °C for 24 h;

[0081] Immerse 2 g of the dried second filter residue in 80 mL of ionic water and perform intermittent shear mixing at a speed of 15000 rpm / min for 10 min for delamination and exfoliation;

[0082] The suspension after delamination and exfoliation is centrifuged at a speed of 300 rpm / min for 25 minutes. The collected supernatant is the dispersion of vermiculite nanosheets (VNs), and then it is centrifuged at a speed of 6000 rpm / min for 45 minutes to concentrate it to a 5 mg / mL VNS dispersion;

[0083] Step 3, prepare polylysine-vermiculite composite aerogel

[0084] Mix 10 mL of a 5 mg / mL VNS dispersion with 1 mL of a 100 mg / mL polylysine aqueous solution, stir at room temperature, and perform ultrasonic treatment in a water bath for 20 minutes; Then add 8 mL of a 10 mg / mL boron nitride aqueous solution, stir at room temperature, and perform ultrasonic treatment in a water bath for 20 minutes, and carry out low-temperature freeze curing for 3 hours; Freeze-dry the obtained polylysine-vermiculite composite aerogel.

[0085] The polylysine / vermiculite composite aerogel material is a hydrogel crosslinked by the electrostatic interaction between polylysine and vermiculite nanosheets (VNs). After freeze-drying, it will generate a highly porous aerogel with an open pore structure, presenting an orderly arranged lamellar structure. Adding boron nitride, it presents a scaly lamellar structure, has a porous and loose property, and is a composite aerogel material convenient for the adsorption of formaldehyde.

[0086] Example 6

[0087] A preparation method of a novel polylysine / vermiculite composite aerogel material provided by an embodiment of the present invention includes the following steps:

[0088] Step 1, prepare modified vermiculite:

[0089] Grind vermiculite particles and dry them at a temperature of 50 °C; Immerse 5.4 g of the dried vermiculite powder in 95 mL of saturated sodium chloride (NaCl) solution, stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h; After cooling for 20 h to room temperature, filter it under vacuum and wash it with 500 mL of pure water until neutral to obtain the first filter residue. Dry the first filter residue in a drying oven at 50 °C for 24 h to obtain modified vermiculite;

[0090] Step 2, prepare a concentrated dispersion of vermiculite nanosheets:

[0091] Weigh 5.4 g of modified vermiculite and immerse it in 80 mL of a lithium chloride (LiCl) solution with a concentration of 1.5 mol / L. Stir it evenly and then add it to a hydrothermal reaction kettle, and react at 110 °C for 2 h. After cooling for 20 h to room temperature, filter it under vacuum and wash it with 500 mL of pure water until neutral to obtain the second filter residue. Dry the second filter residue in a drying oven at 50 °C for 24 h;

[0092] Immerse 5.4 g of the dried second filter residue in 80 mL of ionized water and perform intermittent shear mixing at a speed of 20000 rpm / min for 10 min for delamination and exfoliation;

[0093] Centrifuge the delaminated and exfoliated suspension at a rotational speed of 300 rpm / min for 30 minutes. The collected supernatant is the dispersion of vermiculite nanosheets (VNs). Then centrifuge it at a rotational speed of 6000 rpm / min for 1 h to concentrate it to a 10 mg / mL VNS dispersion;

[0094] Step 3, prepare polylysine-vermiculite composite aerogel

[0095] Mix 5 mL of a 10 mg / mL VNS dispersion with 2 mL of a 40 mg / mL polylysine aqueous solution, stir at room temperature, and perform ultrasonic treatment in a water bath for 20 minutes; Then add 15 mL of a 5 mg / mL boron nitride aqueous solution, stir at room temperature, and perform ultrasonic treatment in a water bath for 20 minutes, and carry out low-temperature freezing and curing for 3 hours; Freeze-dry the obtained polylysine-vermiculite composite aerogel.

[0096] The polylysine / vermiculite composite aerogel material is a hydrogel formed by crosslinking polylysine and vermiculite nanosheets (VNs) through electrostatic interactions. After freeze-drying, it produces a highly porous aerogel with an open pore structure and orderly arranged lamellar structures. The addition of boron nitride creates a scaly lamellar structure, creating a porous and loose composite aerogel material that facilitates formaldehyde adsorption.

[0097] Comparative Example 1

[0098] The preparation method of a polylysine / vermiculite composite aerogel material provided in the comparative example of the present invention comprises the following steps:

[0099] Grind the vermiculite particles and dry them at 50℃.

[0100] Weigh 3.6 g of the dried filter residue and immerse it in 50 mL of deionized water. Shear mixing was performed at a speed of 20,000 rpm / min for 10 min to perform layered exfoliation.

[0101] The suspension after delamination was centrifuged at 300 rpm / min for 1 hour. The collected supernatant was the vermiculite nanosheet (VNs) dispersion, which was then centrifuged at 6000 rpm / min for 1 hour to concentrate it to 5 mg / mL VNS dispersion.

[0102] 10 mL of 10 mg / mL VNS dispersion was mixed with 10 mL of 100 mg / mL polylysine aqueous solution, stirred at room temperature, and ultrasonicated in a water bath for 10 minutes.

[0103] 10 mL of 5 mg / mL boron nitride was added, and the resulting mixture was stirred at room temperature, ultrasonically treated in a water bath for 10 minutes, and freeze-dried to obtain the polylysine-vermiculite composite aerogel.

[0104] Experimental example

[0105] like Figure 1 As shown, SEM: SEM observations show that the aerogels prepared in Examples 1-6 of the present invention all exhibit irregular flaky or blocky structures, with uneven surfaces and numerous bumps. This indicates that the materials have complex surface morphology and a large specific surface area, demonstrating good formaldehyde adsorption performance.

[0106] Performance Testing

[0107] Formaldehyde adsorption experiment: In a 200L closed chamber, the temperature and humidity were controlled at 27°C and 30%. In the chamber, the heating stage was preheated to 80°C, 150 μl of formaldehyde solution was dropped into a glass petri dish and placed on the heating stage for heating for 30 min to completely volatilize the formaldehyde. Then, 15 g of aerogel sample was placed in, and samples were taken at different time points using an air sampler, and the values were recorded. The results are as Figure 3 shown. The aerogels prepared in Examples 1-6 of the present invention and the aerogel prepared in Comparative Example 1 (Control Group 1) can effectively remove formaldehyde under dry conditions. Among them, the aerogel prepared in Example 1 of the present invention can remove up to 99% of formaldehyde within 24 h.

[0108] Formaldehyde scavenging experiment: In a 200L closed chamber, the temperature and humidity were controlled at 27°C and 70%. In the chamber, the heating stage was preheated to 80°C, 150 μl of formaldehyde solution was dropped into a glass petri dish and placed on the heating stage for heating for 30 min to completely volatilize the formaldehyde. Then, 15 g of aerogel sample was placed in, and samples were taken at different time points using an air sampler, and the values were recorded. The results are as Figure 4 shown. The aerogels prepared in Examples 1-6 of the present invention can all effectively remove formaldehyde. Among them, the aerogel prepared in Example 1 of the present invention can still remove 99% of formaldehyde within 24 h. The aldehyde removal effect of the aerogel prepared in Comparative Example 1 (Control Group 1) decays to 50% under high humidity.

[0109] Aerogel cycle life determination experiment: In a 200L closed chamber, the temperature and humidity were controlled at 27°C and 30%. In the chamber, the heating stage was preheated to 80°C, 150 μl of formaldehyde solution was dropped into a glass petri dish and placed on the heating stage for heating for 30 min to completely volatilize the formaldehyde. Then, 10 g of aerogel sample was placed in, and samples were taken at different time points (0 - 24 h) using an air sampler, and the data were recorded. Then, the aerogel materials of Examples 1-6 were placed in an oven at 70°C for formaldehyde desorption (0 - 24 h), which was regarded as one cycle. Five cycles were carried out, and the formaldehyde removal rate was measured each time. The formaldehyde removal rate = formaldehyde concentration at 24 h / initial formaldehyde concentration; The results are as Figure 2 shown. The aerogels prepared in Examples 1-6 of the present invention and the aerogel prepared in Comparative Example 1 (Control Group 1) can effectively remove formaldehyde under dry conditions. After cyclic testing, the formaldehyde removal rates all gradually decreased, and the formaldehyde removal rate of Example 1 was the best after 5 cycles.

[0110] The above has described in detail an embodiment of the present invention, but the content described is only the preferred embodiment of the present invention and cannot be considered as limiting the implementation scope of the present invention. All equivalent changes and improvements made according to the scope of the present invention application should still fall within the scope covered by the patent of the present invention.

Claims

1. A preparation method of a novel polylysine / vermiculite composite aerogel material, characterized in that, It includes the following steps: Hydrothermally treat vermiculite powder with saturated sodium chloride solution to obtain modified vermiculite; Perform secondary hydrothermal treatment on the modified vermiculite with a lithium salt solution to obtain modified vermiculite powder. After the modified vermiculite powder is subjected to shear peeling treatment, gradient centrifugal separation is carried out on the peeled product to obtain a vermiculite nanosheet dispersion; Uniformly mix the vermiculite nanosheet dispersion with an aqueous polylysine solution and perform freeze-drying treatment to obtain a polylysine-vermiculite composite aerogel material with a three-dimensional porous network structure.

2. The preparation method of a novel polylysine / vermiculite composite aerogel material according to claim 1, characterized in that The dosage ratio of vermiculite powder to saturated sodium chloride solution is (1.2 - 5.4) g : (1 - 200) mL.

3. The preparation method of a novel polylysine / vermiculite composite aerogel material according to claim 1, characterized in that The dosage ratio of modified vermiculite to lithium salt solution is (1.2 - 5.4) g : (50 - 150) mL.

4. The preparation method of a novel polylysine / vermiculite composite aerogel material according to claim 1, characterized in that, The amount of substance of the vermiculite nanosheet dispersion is 1 - 10 mol / L.

5. The preparation method of a novel polylysine / vermiculite composite aerogel material according to claim 1, characterized in that The mass ratio of the vermiculite nanosheet dispersion to polylysine is (1 - 100) mg : (1 - 100) mg.

6. The preparation method of a novel polylysine / vermiculite composite aerogel material according to claim 1, characterized in that The mass ratio of the vermiculite nanosheet dispersion to boron nitride is (1 - 100) mg : (1 - 100) mg.

7. The preparation method of a novel polylysine / vermiculite composite aerogel material according to claim 1, characterized in that, The specific steps for gradient centrifugal separation of the peeled product are as follows: First, remove the unpeeled particles by low-speed centrifugation. After collecting the supernatant, perform high-speed centrifugation. The obtained precipitate is redispersed and adjusted to vermiculite nanosheet dispersions with different concentrations.

8. The preparation method of a novel polylysine / vermiculite composite aerogel material according to claim 7, characterized in that, The rotation speed of low-speed centrifugation is 100 - 500 rpm / min, and the time of low-speed centrifugation is 5 - 20 min; The rotation speed of high-speed centrifugation is 5000 - 6000 rpm / min, and the time of high-speed centrifugation is 20 - 40 min.

9. A novel polylysine / vermiculite composite aerogel material, characterized in that The composite aerogel material is prepared by the method described in any one of claims 1 - 8 above. The composite aerogel material is: A hydrogel crosslinked by electrostatic interaction between polylysine and vermiculite nanosheets. After freeze-drying, it will generate a highly porous aerogel with an open pore structure, presenting an ordered lamellar structure; adding boron nitride, it presents a scaly lamellar structure, has a porous and loose property, and is an aerogel material convenient for formaldehyde adsorption.

10. Application of a novel polylysine / vermiculite composite aerogel material, characterized in that, The application of the composite aerogel material prepared by the method described in any one of claims 1 - 8 above in formaldehyde removal.

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