Protein fiber-based composite aerogel material and preparation method thereof

Abstract

The present invention discloses a protein fiber-based composite aerogel material and a preparation method thereof, relating to the technical field of adsorption materials. The protein fiber-based composite aerogel material and preparation method provided by the present invention utilize vegetable-tanned leather fibers as the protein fiber-based raw material of the protein fiber-based composite aerogel. This fully utilizes the photothermal conversion properties of tannins in the vegetable-tanned leather fiber component, reducing the amount of photothermal conversion particles used in the aerogel material preparation process. This improves the photothermal conversion properties of the aerogel material while avoiding the technical problem of three-dimensional structural damage caused by excessive use of photothermal conversion particles. This further enhances the aerogel material's efficient and stable adsorption performance for highly viscous oil stains.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorption materials, and in particular to a protein fiber-based composite aerogel material and a preparation method thereof. Background Art

[0002] As a typical adsorbent material, aerogel has a highly porous structure and a large surface area that can accommodate a large amount of liquid and has excellent oil absorption performance. At the same time, the low density of aerogel enables it to easily float on the water surface after absorbing oil, facilitating the recycling and reuse of oil, making aerogel an ideal choice for treating oil pollution, oil leaks and other liquid pollution.

[0003] The oil absorption principle of traditional aerogel materials is mainly physical adsorption. The oil-water contact angle on the surface of the aerogel material is relatively small, and there is a certain tension at the oil-water interface. When it comes into contact with oil, the tension gathers the oil into the microchannels of the aerogel material pores and is adsorbed by hollow capillaries and macroporous polymers to form a certain thickness.

[0004] While using the aerogel material provided by the related art to perform oil pollution adsorption operations, the inventors discovered that the related art has the following technical problems:

[0005] When the aerogel material provided by the related technology is used in the adsorption scenario of oil pollution, if the oil pollution to be adsorbed is highly viscous, for example, the viscosity of petroleum at room temperature is 103~105mPa·s, then the viscous oil pollution can easily clog the pores of the aerogel material and cannot be effectively adsorbed, resulting in poor adsorption efficiency of the aerogel material for oil pollution and difficulty in recovery. Summary of the Invention

[0006] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a protein fiber-based composite aerogel material and a preparation method thereof. By using vegetable tanned leather fiber as the protein fiber-based raw material of the protein fiber-based composite aerogel, the photothermal conversion performance of the tannin in the vegetable tanned leather fiber component can be fully utilized, and the amount of photothermal conversion particles used in the aerogel material preparation process can be reduced, thereby achieving the goal of improving the photothermal conversion performance of the aerogel material while avoiding the technical problem of damage to the three-dimensional structure caused by excessive use of photothermal conversion particles, thereby improving the efficient and stable adsorption performance of the aerogel material for high-viscosity oil stains. The technical solutions provided by the present invention are as follows:

[0007] According to a first aspect of an embodiment of the present invention, a method for preparing a protein fiber-based composite aerogel material is provided, wherein the method comprises:

[0008] S10: adding the vegetable tanned leather fiber to the dimethyl sulfoxide solvent and keeping the mixture at 80° C. for 30 minutes until the mixture is completely dissolved, thereby obtaining a vegetable tanned leather fiber / dimethyl sulfoxide solution, wherein the content of the vegetable tanned leather fiber in the vegetable tanned leather fiber / dimethyl sulfoxide solution is 5 g / 100 ml;

[0009] S20: After adding chitosan powder to distilled water, slowly adding glacial acetic acid dropwise until the chitosan powder is completely dissolved to obtain a first mixed solution, and then adjusting the pH of the first mixed solution to 4 to obtain a chitosan solution, wherein the content of the chitosan powder in the chitosan solution is 4 g / 100 ml, and the volume ratio of the glacial acetic acid to the distilled water is 1:1;

[0010] S30: mixing the vegetable tanned leather fiber / dimethyl sulfoxide solution, the chitosan solution, and distilled water in a volume ratio of 1-2:1-2:1-2, adding C-NPs with stirring and evenly dispersing to obtain a second mixed solution, then dispensing the second mixed solution into each porous plate, adding glutaraldehyde solution to the second mixed solution in each porous plate, stirring evenly, and then sealing, and keeping warm at 60° C. for 4 h to obtain a composite wet gel semi-finished product, wherein the mass of the C-NPs is 0.15% of the mass of the vegetable tanned leather fiber;

[0011] S40: taking out the composite wet gel semi-finished product from each porous plate and placing it at room temperature for 12-36 hours, soaking the composite wet gel semi-finished product in anhydrous ethanol for 12-36 hours, taking it out, and then soaking the composite wet gel semi-finished product in ultrapure water for another 12-36 hours to obtain a carbon nano-protein-based composite wet gel material;

[0012] S50: placing the carbon nano-protein-based composite wet gel material in a -60°C environment to freeze-form it, and then placing it in a vacuum freeze dryer for freeze drying to obtain a carbon nano-protein-based composite aerogel;

[0013] S60: After the carbon nano-protein-based composite aerogel is immersed in a PDMS hydrophobic agent solution for modification for 2 hours, it is placed in a 120° C. environment for drying for 20 minutes to obtain a protein fiber-based composite aerogel material.

[0014] Preferably, the volume ratio of the vegetable tanned leather fiber / dimethyl sulfoxide solution, the chitosan solution and distilled water in S30 is 2:2:4.

[0015] Preferably, the content of glutaraldehyde in the glutaraldehyde solution is 2.5%, and the volume ratio of the glutaraldehyde solution to the vegetable tanned leather fiber / dimethyl sulfoxide solution in each porous plate is 3:50.

[0016] Preferably, the composite wet gel semi-finished product is allowed to stand at room temperature for 24 hours, is immersed in anhydrous ethanol for 12 hours, and is immersed in ultrapure water for 12 hours.

[0017] Preferably, the content of PDMS in the PDMS hydrophobic agent solution is 1.5%.

[0018] Preferably, the preparation method of the vegetable tanned leather fiber comprises:

[0019] The vegetable tanned leather scraps were cut into 2cm×3cm sizes and then put into a grinder for grinding for 5 minutes to obtain the vegetable tanned leather fiber raw materials;

[0020] The vegetable tanned leather fiber raw material is soaked in anhydrous ethanol for 2-4 days to wash out alcohol-soluble impurities, and then filtered and dried in an environment of 120° C. for 2 hours, and finally put into a grinder for grinding for 5 minutes to obtain the vegetable tanned leather fiber.

[0021] Preferably, the protein fiber-based composite aerogel material is used in petroleum adsorption operations.

[0022] According to a second aspect of an embodiment of the present invention, a protein fiber-based composite aerogel material is provided, characterized in that the protein fiber-based composite aerogel material is prepared by the preparation method of the protein fiber-based composite aerogel material described in any one of 1 above.

[0023] Compared with the prior art, the protein fiber-based composite aerogel material and its preparation method provided by the present invention have the following advantages:

[0024] The present invention provides a protein fiber-based composite aerogel material and a preparation method thereof. The preparation method comprises: adding vegetable tanned leather fiber to a dimethyl sulfoxide solvent, and then keeping the mixture in an 80°C environment for 30 minutes until the mixture is completely dissolved to obtain a vegetable tanned leather fiber / dimethyl sulfoxide solution; adding chitosan powder to distilled water, and then slowly adding glacial acetic acid until the chitosan powder is completely dissolved to obtain a first mixed solution, and then adjusting the pH of the first mixed solution to 4 to obtain a chitosan solution; mixing the vegetable tanned leather fiber / dimethyl sulfoxide solution, the chitosan solution, and distilled water in a volume ratio of 1-2:1-2:1-2, and then stirring and adding C-NPs and uniformly dispersing the mixed solution to obtain a second mixed solution; and then dispensing the second mixed solution into each porous plate, adding glutaraldehyde solution to the second mixed solution in each porous plate, stirring the mixed solution, and then sealing the mixed solution, and then keeping the mixture in an 60°C environment for 4 minutes. h to obtain a composite wet gel semi-finished product, wherein the mass of C-NPs is 0.15% of the mass of the vegetable tanned leather fiber; the composite wet gel semi-finished product is taken out from each porous plate and placed at room temperature for 12-36 hours, and then the composite wet gel semi-finished product is soaked in anhydrous ethanol for 12-36 hours and then taken out, and then the composite wet gel semi-finished product is further soaked in ultrapure water for 12-36 hours to obtain a carbon nano-protein-based composite wet gel material; the carbon nano-protein-based composite wet gel material is placed in a -60°C environment for freeze molding, and then sent to a vacuum freeze dryer for freeze drying to obtain a carbon nano-protein-based composite aerogel; the carbon nano-protein-based composite aerogel is soaked and modified with a PDMS hydrophobic agent solution for 2 hours, and then placed in a 120°C environment for drying for 20 minutes to obtain a protein fiber-based composite aerogel material. The present invention utilizes the photothermal conversion performance of tannin in the vegetable tanned leather fiber component to reduce the amount of photothermal conversion particles used in the preparation process of aerogel materials, thereby improving the photothermal conversion performance of the aerogel material while avoiding the problem of three-dimensional structure damage caused by excessive use of photothermal conversion particles, thereby improving the efficient and stable adsorption performance of the aerogel material for high-viscosity oil stains. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0026] Figure 1 The figure is a flow chart of a method for preparing a protein fiber-based composite aerogel material according to an exemplary embodiment of the present invention.

[0027] Figure 2 FIG1 is a schematic diagram of preparing a plantation tanned leather fiber according to an exemplary embodiment of the present invention.

[0028] Figure 3 1 is a scanning electron microscope image of four aerogels shown in the present invention.

[0029] Figure 4Schematic diagram of the rebound performance test results of the aerogel shown in the present invention.

[0030] Figure 5 This is a schematic diagram of the adsorption rate of three oils by PDMS@C-PCA provided by the present invention at room temperature.

[0031] Figure 6 Schematic diagram of the photothermal performance analysis experiment of the aerogel shown in the present invention.

[0032] Figure 7 Schematic diagram of the temperature change of the aerogel under a simulated light source shown in the present invention.

[0033] Figure 8 Schematic diagram of the ultrasonic stability analysis experiment of aerogel shown in the present invention. DETAILED DESCRIPTION

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] To facilitate understanding of the technical solution provided by the present invention, before specifically describing the preparation method of a protein fiber-based composite aerogel material provided by the present invention, the following terms involved in the specific embodiments of the present invention are explained as follows:

[0036] Photothermal conversion: refers to the phenomenon of photoinduced heating, which usually means that the material heats up when exposed to light. There are three main photothermal conversion mechanisms: plasma interface vibration, non-radiative relaxation, and molecular thermal vibration.

[0037] Photothermal conversion particles: Based on the above photothermal conversion mechanism, they are divided into the following three categories:

[0038] 1) Particles that absorb photons through electron transitions and generate resonant temperature rise to achieve photothermal conversion, such as Au, Ag, Pd, Pt, Al, etc.

[0039] 2) When exposed to light, electron-hole pairs are generated, which relax and radiate energy, resulting in heat generation in semiconductor particles;

[0040] 3) Particles that absorb sunlight energy and generate heat through electron transitions are mainly black carbon-based materials, such as graphene, carbon nanotubes, carbon dots, etc., which use π-π conjugated bonds to convert the absorbed energy into heat energy. The C-NPs used in this invention are such photothermal conversion particles.

[0041] Photothermal oil absorption: A technology that uses solar energy to adsorb and decompose oil. Because crude oil is very viscous at room temperature, the adsorbent material needs to raise the temperature of the crude oil to reduce its viscosity and increase its fluidity, facilitating adsorption and improving adsorption efficiency. The photothermal adsorbent rapidly heats up on its upper surface in sunlight, conducting heat to raise the temperature of its lower surface. Direct contact with the oil reduces its viscosity upon heating, enabling the adsorbent to function smoothly and improving oil absorption efficiency for oil treatment and recovery.

[0042] Figure 1 FIG. 1 is a flow chart of a method for preparing a protein fiber-based composite aerogel material according to an exemplary embodiment of the present invention. Figure 1 As shown, the preparation method of the protein fiber-based composite aerogel material is characterized in that the preparation method comprises:

[0043] S10: After adding the vegetable tanned leather fiber to the dimethyl sulfoxide solvent, the mixture is kept warm at 80° C. for 30 minutes until it is completely dissolved, thereby obtaining a vegetable tanned leather fiber / dimethyl sulfoxide solution, wherein the content of the vegetable tanned leather fiber in the vegetable tanned leather fiber / dimethyl sulfoxide solution is 5 g / 100 ml.

[0044] Preferably, the preparation method of the vegetable tanned leather fiber comprises:

[0045] The vegetable tanned leather scraps are cut into 2cm×3cm sizes, and then sent to a grinder for grinding for 5 minutes to obtain vegetable tanned leather fiber raw materials; the vegetable tanned leather fiber raw materials are soaked in anhydrous ethanol for 2-4 days to wash out alcohol-soluble impurities, and then filtered and placed in a 120°C environment for drying for 2 hours, and finally sent to a grinder for grinding for 5 minutes to obtain vegetable tanned leather fibers.

[0046] The preparation diagram of vegetable tanned leather fiber can be shown as follows: Figure 2 As shown, the preparation order is Figure 2 1A, 1B, 1C, 1D, 1E.

[0047] S20: After adding chitosan powder to distilled water, continue to slowly add glacial acetic acid until the chitosan powder is completely dissolved to obtain a first mixed solution, and then adjust the pH of the first mixed solution to 4 to obtain a chitosan solution, wherein the content of the chitosan powder in the chitosan solution is 4 g / 100 ml, and the volume ratio of the glacial acetic acid to the distilled water is 1:1.

[0048] S30: After mixing the vegetable tanned leather fiber / dimethyl sulfoxide solution, the chitosan solution and distilled water in a volume ratio of 1-2:1-2:1-2, C-NPs are added with stirring and dispersed evenly to obtain a second mixed liquid. After the second mixed liquid is divided into each porous plate, glutaraldehyde solution is added to the second mixed liquid in each porous plate, the plate is stirred and sealed, and the mixture is kept warm at 60°C for 4 hours to obtain a composite wet gel semi-finished product, wherein the mass of the C-NPs is 0.15% of the mass of the vegetable tanned leather fiber.

[0049] S40: The composite wet gel semi-finished product is taken out from each porous plate and placed at room temperature for 12-36 hours, and then the composite wet gel semi-finished product is soaked in anhydrous ethanol for 12-36 hours and then taken out, and then the composite wet gel semi-finished product is further soaked in ultrapure water for 12-36 hours to obtain a carbon nano-protein-based composite wet gel material.

[0050] Among them, the step of removing the composite wet gel semi-finished product from each porous plate and placing it at room temperature for 12-36 hours allows the sol inside the composite wet gel semi-finished product to fully age the gel under the cross-linking action of glutaraldehyde; the step of soaking the composite wet gel semi-finished product in anhydrous ethanol for 12-36 hours and then taking it out allows the fillers in the wet gel network of the composite wet gel semi-finished product, mainly DMSO, residual glutaraldehyde, etc. in the reaction to be fully replaced; and the step of continuing to soak the composite wet gel semi-finished product in ultrapure water for 12-36 hours is intended to facilitate its subsequent freeze-drying molding process.

[0051] S50: placing the carbon nano-protein-based composite wet gel material in a -60°C environment to freeze-form it, and then sending it into a vacuum freeze dryer for freeze drying to obtain a carbon nano-protein-based composite aerogel.

[0052] Through the processing in step S50, the solvent liquid in the carbon nano-protein-based composite wet gel material is frozen and solidified at low temperatures. Then, under vacuum conditions, the solvent is directly sublimated from the solid state to form an aerogel. Under these conditions, the liquid is replaced with ultrapure water or anhydrous ethanol and then removed by sublimation. The solid support structure in the gel is maintained intact during the drying process, thus forming a high-porosity, low-density aerogel.

[0053] S60: After the carbon nano-protein-based composite aerogel is immersed in a PDMS hydrophobic agent solution for modification for 2 hours, it is placed in a 120° C. environment for drying for 20 minutes to obtain a protein fiber-based composite aerogel material.

[0054] It should be noted that the effect of the amount of photothermal conversion particles on aerogel formation is mainly the stability of its internal three-dimensional network structure. In order to make the aerogel material have better photothermal conversion performance to meet the aerogel material's adsorption requirements for oils, the preparation process of aerogel materials provided by related technologies often requires the use of a large amount of photothermal conversion particles, which can easily lead to a large load of photothermal conversion particles on the surface of the three-dimensional structure of the prepared aerogel material, thereby reducing the cross-linking effect of the cross-linking agent, and further making the three-dimensional network structure of the prepared aerogel material unable to maintain a long-term stable state after vacuum drying treatment, and the physical resistance is poor, and it cannot be applied to the long-term stable operation of actual marine oil pollution adsorption.

[0055] Vegetable tanned leather is tanned mainly with vegetable tanning agents. Vegetable tanning agents mainly use vegetable tanning materials and vegetable tannins. Vegetable tannins are polyphenolic compounds such as tannins and plant polyphenols contained in plants that can turn raw hides into leather. The present invention uses vegetable tanned leather fibers as raw materials for preparing carbon nano-protein-based composite aerogels, utilizes a large number of π-π conjugated bonds contained in the hydrolyzed acid of tannin, a component of the fiber, to cause mutual influence of electron clouds, absorb solar energy and vibrate, and generate heat energy through the optical transition of the π-π bonds, so that the aerogel material has a certain initial photothermal conversion performance. Then, by doping a small amount of photothermal conversion particles C-NPs and designing a corresponding process flow, the photothermal conversion performance of the prepared carbon nano-protein-based composite aerogel meets the requirements of its application in photothermal oil absorption, while avoiding the problems of unstable three-dimensional network structure and poor physical properties of the aerogel material caused by doping with a large number of photothermal conversion particles. In addition, the doping of an appropriate amount of C-NPs can also increase the roughness of the surface of the aerogel material. The rough surface layer and the microporous structure both increase the specific surface area of ​​the aerogel material, which is more conducive to the adsorption and storage of oil products.

[0056] Preferably, the volume ratio of the vegetable tanned leather fiber / dimethyl sulfoxide solution, the chitosan solution and distilled water in S30 is 2:2:4.

[0057] Preferably, the content of glutaraldehyde in the glutaraldehyde solution is 2.5%, and the volume ratio of the glutaraldehyde solution to the vegetable tanned leather fiber / dimethyl sulfoxide solution in each porous plate is 3:50.

[0058] Preferably, the composite wet gel semi-finished product is allowed to stand at room temperature for 24 hours, is immersed in anhydrous ethanol for 12 hours, and is immersed in ultrapure water for 12 hours.

[0059] Preferably, the content of PDMS in the PDMS hydrophobic agent solution is 1.5%.

[0060] Preferably, the protein fiber-based composite aerogel material is used in petroleum adsorption operations.

[0061] In order to better illustrate the technical effects of the protein fiber-based composite aerogel material and the preparation method thereof provided by the present invention, the following experimental tests were conducted on the protein fiber-based composite aerogel material provided by the present invention. For ease of reading, the English abbreviations of the reagents correspond to the following:

[0062] Vegetable tanned leather fiber: VTLF, Vegetable Tanned Leather Fiber;

[0063] Dimethyl sulfoxide: DMSO;

[0064] Chitosan: CS;

[0065] Carbon nano-protein-based composite aerogel: C-PCA, C-NPs-Protein-based Composite Aerogel;

[0066] Protein fiber-based composite aerogel: PDMS@C-PCA.

[0067] The reagents and materials used in the experiment are shown in Table 1. Most of the reagents were of analytical and chemical purity.

[0068] Table 1

[0069]

[0070]

[0071] Benchmark Experiment Example

[0072] S10: After cutting 10 g of vegetable tanned leather scraps into 2 cm × 3 cm sizes, the raw materials were ground in a grinder for 5 minutes to obtain a vegetable tanned leather fiber raw material; the raw materials were soaked in anhydrous ethanol for 2 days to wash out alcohol-soluble impurities, and then filtered and dried at 120° C. for 2 hours. Finally, the raw materials were ground in a grinder for 5 minutes to obtain VTLF.

[0073] S20: 5 g of VTLF was added to 100 ml of DMSO solvent and kept at 80° C. for 30 min until completely dissolved to obtain a VTLF / DMSO solution.

[0074] S30: After adding 4 g of CS powder to 100 ml of distilled water, 100 ml of glacial acetic acid was slowly added dropwise until the CS powder was completely dissolved to obtain a first mixed solution, and then the pH of the first mixed solution was adjusted to 4 to obtain a CS solution.

[0075] S40: After mixing VTLF / DMSO solution, CS solution and distilled water in a volume ratio of 2:2:4, C-NPs were added with stirring and dispersed evenly to obtain a second mixed solution. The second mixed solution was then dispensed into each porous plate, and a 2.5% glutaraldehyde solution was added to the second mixed solution in each porous plate, stirred evenly and sealed. The mixture was kept warm at 60°C for 4 hours to obtain a composite wet gel semi-finished product, wherein the mass of the C-NPs was 0.15% of the mass of the VTLF.

[0076] S50: The composite wet gel semi-finished product is taken out from each porous plate and placed at room temperature for 12 hours, and then the composite wet gel semi-finished product is soaked in anhydrous ethanol for 12 hours and then taken out, and then the composite wet gel semi-finished product is further soaked in ultrapure water for 12 hours to obtain a carbon nano-protein-based composite wet gel material.

[0077] S60: The carbon nano-protein-based composite wet gel material is placed in a -60°C environment for freezing and forming, and then sent to a vacuum freeze dryer for freeze drying to obtain C-PCA.

[0078] S70: After the C-PCA is immersed in a 1.5% PDMS hydrophobic agent solution for modification for 2 hours, it is placed in a 120° C. environment for drying for 20 minutes to obtain PDMS@C-PCA.

[0079] Based on the above benchmark experimental example, the amount of VTFL / DMSO was set to 20 ml for experimental testing and optimization. The chitosan ratio, glutaraldehyde dosage, C-NPs content, aging and water change time were used as influencing factors, and the molding effect of the synthesized aerogel was used as the inspection index for optimization and adjustment. The four factors were independently subjected to single-factor experimental design, and the optimization results of each single factor were directly used in the next single-factor experimental design. The details are as follows:

[0080] (1) Experiment on the effect of chitosan ratio on wet gel forming properties

[0081] The effect of chitosan on the moldability of aerogels is reflected in the wet gel molding effect and is determined by subjective evaluation. The role of adding chitosan to assist molding is that the reaction between chitosan and glutaraldehyde is more stable. The addition of water is necessary for hydrogel molding and also to reduce the solid content and density of the molded aerogel. Using too little chitosan and adding too much water may result in insufficient mechanical properties of the wet gel. Adding too much water may result in poor molding and may affect the subsequent reaction rate. As shown in the chitosan ratio optimization test results in Table 2 below, the preferred ratio scheme is determined to be 2:2:4 (V:V:V).

[0082] Table 2

[0083] Test number VTFL / DMSO:CS:H2O(V:V:V) Molding effect 1 2：2：2 Poor molding and breakage 2 2：2：3 General molding 3 2：2：4 Complete molding 4 2：2：5 Poor molding and insufficient mechanical properties 5 2：1；2 General molding 6 2：1：3 Incomplete molding 7 2：1：4 Incomplete molding, broken 8 2：1：5 Poor molding

[0084] (2) Experiment on the effect of glutaraldehyde dosage on aerogel formability

[0085] The optimal glutaraldehyde dosage was selected based on the aerogel formability. The results are shown in Table 3. The optimal glutaraldehyde dosage under the optimal ratio of 2:2:4 in (1) was 1.2 ml. A smaller amount of glutaraldehyde results in incomplete reaction within the system, affecting formability. An excessive amount of glutaraldehyde can lead to uneven reaction within the porous plate, resulting in excessive surface tension at 60°C and cracking of the surface, resulting in poor formability. Alternatively, the glutaraldehyde reaction can be more intense, destroying the three-dimensional structure and causing collapse after drying.

[0086] Table 3

[0087]

[0088]

[0089] (3) Experiment on the effect of C-NPs dosage on aerogel formability

[0090] The results of the C-NPs dosage optimization test on aerogels are shown in Table 4. The effect of C-NPs dosage on aerogel formation is mainly due to the internal three-dimensional network structure. When the C-NPs dosage is large, the surface load of the three-dimensional structure is high, the cross-linking effect of glutaraldehyde is weakened, and the three-dimensional network has insufficient support after vacuum drying, resulting in a more serious morphological breakage into powder. Therefore, in the scheme (2), the optimal C-NPs content is 0.15%.

[0091] Table 4

[0092] serial number C-NPs dosage / % (VTLF) Forming effect after drying 1 3 Broken, shapeless 2 2 Poor molding and breakage 3 1.5 General molding, some breakage 4 1 Incomplete molding 5 0.15 More complete molding

[0093] (4) Experiment on the effects of static aging and water change time on the formability of wet gel and aerogel

[0094] Table 5 shows the optimal results of tests on the effects of static aging and water exchange time on the formability of wet gels and aerogels. Insufficient static aging time leads to incomplete glutaraldehyde reaction, incomplete wet gel formation, and a lack of porosity and elasticity in the unformed portion after drying. Insufficient water exchange time can cause the solvent DMSO and some unreacted glutaraldehyde to remain in the reaction system, affecting porosity. Excessive water exchange time can cause the wet gel to swell, destroying the internal three-dimensional structure and causing severe collapse after drying. Overall, the optimal solution is a static aging and water exchange time of 24 hours each.

[0095] Table 5

[0096]

[0097]

[0098] Based on the optimization results of the above four single-factor experiments, the optimal preparation process of C-PCA is: VTFL / DMSO:CS:H2O (V:V:V) 2:2:4; glutaraldehyde dosage is 1.2 ml; C-NPs content is 0.15%, and after keeping warm for 4 hours, the static aging and water change time are 24 hours each.

[0099] Furthermore, the structural characterization and performance testing of the PDMS@C-PCA corresponding to the C-PCA prepared under the above optimal preparation process were carried out, and the data results were obtained as follows:

[0100] Microscopic morphology observation of aerogel

[0101] A small piece of aerogel material was taken from the inside of chitosan aerogel (CA), protein-based composite aerogel (PCA), PDMS@PCA, and PDMS@C-PCA, and then cut, dried, fixed, and gold-sprayed. Then, a field emission scanning electron microscope was used to observe the surface morphology of the material at a working voltage of 15kV and analyze the surface structure of each sample at a parameter of 1000 times. The results are as follows Figure 3 Scanning electron micrographs of the four aerogels shown. Figure 3 As can be seen from (a), the interior of chitosan aerogel (CA) is mainly composed of lamellar pores. Figure 3 The disordered pore cross-distribution structure inside the protein-based composite aerogel (PCA) in (b) is more conducive to the adsorption of oil. Figure 3 In (c), the PDMS hydrophobic layer on the PDMS@PCA surface is relatively smooth, and PDMS is coated more evenly on the surface, indicating that the hydrophobic modification is relatively successful. Figure 3 Although the surface of PDMS@C-PCA in (d) has a hydrophobic layer, it is a rough surface with uneven spots, which indicates that the dispersion of C-NPs is relatively uniform. In addition, there are many micropores in the cross section. The rough surface and microporous structure increase the specific surface area of ​​the material, which is more conducive to the adsorption and storage of oil products. Therefore, PDMS@C-PCA has better oil absorption capacity. According to actual measurements, the density of PDMS@C-PCA can reach 20mg / cm 3 .

[0102] Aerogel rebound performance test

[0103] Aerogel materials are mainly subjected to a compression-adsorption cycle when reused, so the quality of the material's rebound performance has a direct impact on its reusability, so there are certain requirements for the material's rebound performance. The prepared aerogel was subjected to a compression rebound test. The sample was deformed under a fixed compression force (200g weight), and then the weight was released to observe whether the sample returned to its original shape and the degree of recovery. The test was repeated 20 times, and its rebound height and rebound time were recorded to evaluate its compression rebound performance. The rebound performance test results of aerogel are as follows: Figure 4 As shown, in Figure 4 In the figure, a is a schematic diagram of the rebound performance corresponding to chitosan aerogel, b is a schematic diagram of the rebound performance corresponding to C-PCA aerogel, and c is a schematic diagram of the rebound performance corresponding to PDMS@C-PCA aerogel.

[0104] Depend on Figure 4 As can be seen, when a 200g weight was placed on each of the three aerogels and completely compressed without deformation, and then the weight was removed, the chitosan aerogel showed almost no deformation and lacked compression resilience. The C-PCA exhibited minimal deformation and fully recovered after 10 seconds, demonstrating moderate compression resilience. However, the PDMS@C-PCA exhibited significant deformation and recovered rapidly within 2 seconds after the pressure was removed, achieving a recovery rate of almost 100%. During the compression phase, even at a deformation rate of 80%, the PDMS@C-PCA exhibited no cracking or collapse, demonstrating an elastic recovery rate of almost 100%, demonstrating excellent resilience. Importantly, the elastic recovery rate remained high at 92.8% even after 20 compression-release cycles, though recovery took longer. This demonstrates the excellent structural robustness and reusability of the PDMS@C-PCA, making it a highly valuable material for oil absorption applications.

[0105] Aerogel oil absorption performance analysis experiment

[0106] Take 0.3g of PDMS@C-PCA aerogel material and test the oil absorption rate of three oils (petroleum oil, motor oil, and rapeseed oil). Pour 20ml of oil into a beaker and place the weighed PDMS@C-PCA (M0 = 0.5g) flatly in the oil and let it stand for 10 minutes. Take out the aerogel from the beaker and place it flat on a metal filter for 5 minutes. Weigh the mass of the aerogel after standing (M1) and calculate the average oil absorption rate. Test each oil 10 times and take the average oil absorption to calculate the oil absorption rate C. The calculation formula of the oil absorption rate C is as shown in Formula 1:

[0107]

[0108] The calculated oil absorption test results of PDMS@C-PCA aerogel for three oils (petroleum oil, motor oil, and rapeseed oil) are shown in Table 6.

[0109] Table 6

[0110] Oil type <![CDATA[Mass M0 of the aerogel oil absorbent / g]]> <![CDATA[Average oil absorption M1 / g]]> Oil absorption rate / (g / g) rapeseed oil 0.30 8.125 27.30 engine oil 0.30 7.580 25.27 oil 0.30 9.337 30.13

[0111] As shown in Table 6, PDMS@C-PCA exhibits excellent adsorption for the three oils, with maximum adsorption rates reaching 27.3 g / g for rapeseed oil, 25.27 g / g for motor oil, and 30.13 g / g for petroleum oil, respectively. Clearly, the modified aerogel exhibits the best adsorption for petroleum oil, with oil adsorption rates exceeding 30 times. The excellent adsorption performance of PDMS@C-PCA for the three oils is primarily due to the presence of porous regions within the aerogel, which provide an adsorption effect, as well as the high number of pores within the three-dimensional space of the prepared material, resulting in a large specific surface area and strong adsorption capacity.

[0112] Furthermore, the oil absorption rate of PDMS@C-PCA aerogel material for three kinds of oil (petroleum, motor oil, rapeseed oil) was tested. An appropriate amount of oil was poured into a beaker and PDMS@C-PCA aerogel material was added. 1S, 2S, 3S, 4S, 5S, 10S, 15S, 20S, 30S, 40S, 50S, 60S, 90S, and 120S were taken as time points to test the oil absorption rate of PDMS@C-PCA at these time points. The above experimental operations were repeated in sequence and the experimental data were recorded. A curve with time as the horizontal axis and the oil absorption rate as the vertical axis was drawn. The straight line part of the curve was taken to calculate the oil absorption rate. The calculation formula of the oil absorption rate v is shown in Formula 2:

[0113]

[0114] In formula 2, v represents the average oil absorption rate, in g / (g / min); C max Indicates the adsorption capacity at adsorption saturation, unit is g; t max It indicates the time for adsorption to reach saturation, in min.

[0115] The calculated adsorption rates of PDMS@C-PCA for the three oils at room temperature are as follows: Figure 5 As shown, a is the oil absorption rate diagram of PDMS@C-PCA within 120S. Figure 5 It can be seen that the oil absorption process of PDMS@C-PCA is divided into two stages: rapid adsorption process and adsorption equilibrium stage.

[0116] like Figure 5As shown, PDMS@C-PCA adsorbs all three oils well. The oil absorption for rapeseed oil and motor oil reaches a plateau around 10 seconds, with absorption rates of 26.3 g / g and 24.7 g / g, respectively. The absorption rate for petroleum oil reaches equilibrium around 20 seconds, and after 1 minute, the absorption remains essentially constant, reaching saturation. With further adsorption time, the absorption for rapeseed oil and motor oil does not increase significantly, indicating that the initial interaction between the adsorbent and the oil is primarily physical adsorption at the porous sites.

[0117] Photothermal performance analysis experiment of aerogel

[0118] The photothermal conversion test was carried out according to the device shown in the figure below, where the top surface is defined as facing the simulated sunlight source, and the bottom surface is defined as facing away from the simulated sunlight source. Figure 6 As shown, a cold xenon lamp light source was used to simulate sunlight conditions (1000W / m 2 ), with a distance of one sun (10 cm), and an infrared camera was used to record the temperature changes and the actual temperature of the sample, and to analyze the heating rate and thermal conductivity, and to evaluate the photothermal conversion effect of the material.

[0119] Starting from the moment the simulated sunlight source is turned on, the temperature-time curves of the top and bottom surfaces are measured using an infrared camera. The heating rate of the top surface and the thermal conductivity of the material are calculated. The heating rate V is calculated as shown in Formula 3:

[0120]

[0121] In formula 3, T t is the temperature of the center point of the top surface after irradiation tS; T0 is the initial temperature of the center point of the bottom surface; t is the irradiation time of the simulated solar light source.

[0122] The thermal conductivity is calculated using the Fourier equation, as shown in Formula 4:

[0123]

[0124] In formula 4, Q (kW / m 2 ) represents the heat flux, that is, the power of the energy supply source; k represents the thermal conductivity of the material; ΔT (°C) represents the temperature difference between the top and bottom surfaces of the material; ΔX (m) represents the thickness of the material; ΔT / ΔX represents the temperature gradient of the sample under the irradiation of the light source.

[0125] The temperature-time curves of the top and bottom surfaces of C-PCA were measured using an infrared camera and compared with PCA to explore the effect of C-NPs on the photothermal oil absorption performance. The temperature change diagram is shown in the figure below. Figure 7 As shown, Figure 7In (a), A1 is the temperature change curve of the top of C-PCA, A2 is the temperature change curve of the bottom of C-PCA, B1 is the temperature change curve of the top of PCA, and B2 is the temperature change curve of the bottom of PCA; Figure 7 In (b), C1 is the temperature change curve of the top of C-PCA under periodic switching light source, and C2 is the temperature change curve of the bottom of C-PCA under periodic switching light source.

[0126] The top temperature of C-PCA increased from 25°C to 95°C within 50 seconds, and the temperature gradually reached equilibrium after 100 seconds. The heating rate in the rapid heating stage was 1.4°C / S. Figure 7 During the heating phase (a), the top surfaces of both PCA and C-PCA heat up at a rapid rate, with similar peak temperatures. However, the bottom surfaces show a significant temperature difference. This is primarily due to the excellent thermal conductivity of the C-NPs in C-PCA, which allows heat from the top surface to be quickly transferred to the bottom surface, resulting in a significant temperature increase. Furthermore, as shown in (b), the top and bottom surfaces of the C-PCA rapidly rise in temperature when exposed to simulated sunlight. Upon turning off the light source, the top and bottom surface temperatures drop dramatically, indicating that the temperature increase on the bottom surface of the C-PCA is due to thermal conduction from the heated top surface, and this heat conduction is rapid. Furthermore, the C-PCA temperature rises to 99.8°C within 120 seconds and remains stable after repeated heating. The bottom surface shows the same trend, rising to 47.8°C and remaining stable, demonstrating the excellent photothermal stability of the surface material. Therefore, the addition of C-NPs significantly improves thermal conductivity, giving the C-PCA material efficient photothermal conversion performance, sufficient for practical applications in photothermal oil absorption.

[0127] also, Figure 7 (a) It can be seen that the overall trend of the heating curves of PCA without C-NPs and C-PCA is similar, and the top temperature rise value is slightly lower, while the bottom surface is quite different. This is because the vegetable tanning agent used in the preparation of vegetable tanned animal leather contains a large amount of plant gum (plant adhesive), the main component of which is tannin. The hydrolyzed acid in tannin contains a large number of π-π conjugated bonds, which cause the mutual influence of electron clouds, absorb solar energy and vibrate, and generate heat energy through the optical transition of π-π bonds. This is the natural characteristic of vegetable tanned leather. Therefore, PCA has self-heating properties under light, and the reason why the bottom temperature of PCA is low is that the thermal conductivity is insufficient, which is poorer than the effect containing C-NPs. This also proves that the C-PCA material has good thermal conductivity.

[0128] Ultrasonic stability analysis experiment of aerogel

[0129] 0.2 g of PDMS@C-PCA loaded with nanoparticles was put into 100 ml of simulated seawater and ultrasonicated in an ultrasonic cleaning machine for 10 min, 20 min, 40 min, and 60 min, respectively. After the ultrasonication, the water was observed to see if there were any suspended nanoparticles to determine the adhesion strength of the C-NPs nanoparticles in the PDMS@C-PCA. The schematic diagram of the solution changes after ultrasonication is shown in the figure below. Figure 8 shown.

[0130] pass Figure 8 It can be seen that after ultrasonic treatment for 10 min, 30 min, and 60 min, the solution is still clear and there are no suspended C-NPs, which proves that PDMS@C-PCA has good ultrasonic stability.

[0131] In summary, the present invention provides a protein fiber-based composite aerogel material and a preparation method thereof, which comprises: adding vegetable tanned leather fiber to a dimethyl sulfoxide solvent, and keeping it warm at 80°C for 30 minutes until it is completely dissolved to obtain a vegetable tanned leather fiber / dimethyl sulfoxide solution; adding chitosan powder to distilled water, and then slowly adding glacial acetic acid until the chitosan powder is completely dissolved to obtain a first mixed solution, and then adjusting the pH of the first mixed solution to 4 to obtain a chitosan solution; mixing the vegetable tanned leather fiber / dimethyl sulfoxide solution, the chitosan solution and distilled water in a volume ratio of 1-2:1-2:1-2, stirring and adding C-NPs and dispersing them evenly to obtain a second mixed solution, and then dividing the second mixed solution into each porous plate, adding glutaraldehyde solution to the second mixed solution in each porous plate, stirring evenly and sealing, and then keeping the mixture at 60°C. The composite wet gel semi-finished product is obtained by keeping warm for 4 hours, and the mass of C-NPs is 0.15% of the mass of the vegetable tanned leather fiber; the composite wet gel semi-finished product is taken out from each porous plate and placed at room temperature for 12-36 hours, and then the composite wet gel semi-finished product is soaked in anhydrous ethanol for 12-36 hours and then taken out, and then the composite wet gel semi-finished product is soaked in ultrapure water for another 12-36 hours to obtain a carbon nano-protein-based composite wet gel material; the carbon nano-protein-based composite wet gel material is placed in a -60°C environment for freeze molding, and then sent to a vacuum freeze dryer for freeze drying to obtain a carbon nano-protein-based composite aerogel; the carbon nano-protein-based composite aerogel is soaked and modified with a PDMS hydrophobic agent solution for 2 hours, and then placed in a 120°C environment for drying for 20 minutes to obtain a protein fiber-based composite aerogel material. The present invention utilizes the photothermal conversion performance of tannin in the vegetable tanned leather fiber component to reduce the amount of photothermal conversion particles used in the preparation process of aerogel materials, thereby improving the photothermal conversion performance of the aerogel material while avoiding the problem of three-dimensional structure damage caused by excessive use of photothermal conversion particles, thereby improving the efficient and stable adsorption performance of the aerogel material for high-viscosity oil stains.

[0132] Although the present invention has been described in detail above using general explanations, specific embodiments, and experiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements that do not depart from the spirit of the present invention are intended to be within the scope of protection claimed herein.

[0133] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof.

Claims

1. A method for preparing a protein fiber-based composite aerogel material, characterized in that: The preparation method comprises: S10: adding the vegetable tanned leather fiber to the dimethyl sulfoxide solvent and keeping the mixture at 80° C. for 30 minutes until the mixture is completely dissolved, thereby obtaining a vegetable tanned leather fiber / dimethyl sulfoxide solution, wherein the content of the vegetable tanned leather fiber in the vegetable tanned leather fiber / dimethyl sulfoxide solution is 5 g / 100 ml; S20: After adding chitosan powder to distilled water, slowly adding glacial acetic acid dropwise until the chitosan powder is completely dissolved to obtain a first mixed solution, and then adjusting the pH of the first mixed solution to 4 to obtain a chitosan solution, wherein the content of the chitosan powder in the chitosan solution is 4 g / 100 ml, and the volume ratio of the glacial acetic acid to the distilled water is 1:1; S30: mixing the vegetable tanned leather fiber / dimethyl sulfoxide solution, the chitosan solution, and distilled water in a volume ratio of 1-2:1-2:1-2, adding C-NPs with stirring and evenly dispersing to obtain a second mixed solution, then dispensing the second mixed solution into each porous plate, adding glutaraldehyde solution to the second mixed solution in each porous plate, stirring evenly, and then sealing, and keeping warm at 60° C. for 4 h to obtain a composite wet gel semi-finished product, wherein the mass of the C-NPs is 0.15% of the mass of the vegetable tanned leather fiber; S40: taking out the composite wet gel semi-finished product from each porous plate and placing it at room temperature for 12-36 hours, soaking the composite wet gel semi-finished product in anhydrous ethanol for 12-36 hours, taking it out, and then soaking the composite wet gel semi-finished product in ultrapure water for another 12-36 hours to obtain a carbon nano-protein-based composite wet gel material; S50: placing the carbon nano-protein-based composite wet gel material in a -60°C environment to freeze-form it, and then placing it in a vacuum freeze dryer for freeze drying to obtain a carbon nano-protein-based composite aerogel; S60: After the carbon nano-protein-based composite aerogel is immersed in a PDMS hydrophobic agent solution for modification for 2 hours, it is placed in a 120° C. environment for drying for 20 minutes to obtain a protein fiber-based composite aerogel material.

2. The preparation method according to claim 1, characterized in that The volume ratio of the vegetable tanned leather fiber / dimethyl sulfoxide solution, the chitosan solution and distilled water in S30 is 2:2:

4.

3. The preparation method according to claim 1, characterized in that The content of glutaraldehyde in the glutaraldehyde solution is 2.5%, and the volume ratio of the glutaraldehyde solution to the vegetable tanned leather fiber / dimethyl sulfoxide solution in each porous plate is 3:

50.

4. The preparation method according to claim 1, characterized in that The composite wet gel semi-finished product is allowed to stand at room temperature for 24 hours, is immersed in anhydrous ethanol for 12 hours, and is immersed in ultrapure water for 12 hours.

5. The preparation method according to claim 1, characterized in that The content of PDMS in the PDMS hydrophobic agent solution is 1.5%.

6. The preparation method according to claim 1, characterized in that The preparation method of the vegetable tanned leather fiber comprises: The vegetable tanned leather scraps were cut into 2cm×3cm sizes and then put into a grinder for grinding for 5 minutes to obtain the vegetable tanned leather fiber raw materials; The vegetable tanned leather fiber raw material is soaked in anhydrous ethanol for 2-4 days to wash out alcohol-soluble impurities, and then filtered and dried in an environment of 120° C. for 2 hours, and finally put into a grinder for grinding for 5 minutes to obtain the vegetable tanned leather fiber.

7. The preparation method according to claim 1, characterized in that The protein fiber-based composite aerogel material is used in petroleum adsorption operations.

8. A protein fiber-based composite aerogel material, characterized in that: The protein fiber-based composite aerogel material is prepared by the method for preparing the protein fiber-based composite aerogel material according to any one of claims 1 to 7.

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