A self-heating, wood-based compressible, resilient, hydrophobic, and oleophilic carbon sponge, its preparation method, and its applications.

Abstract

This invention relates to a method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge, comprising the following steps: (1) cutting wood into blocks; (2) immersing the wood blocks in boiling alkaline solution; (3) immersing the wood blocks treated in step (2) in hydrogen peroxide solution; (4) drying the wood blocks to remove moisture; (5) immersing the dried wood blocks in silane-modified solution; (6) drying the modified wood blocks treated in step (5) and then carbonizing them; (7) immersing the carbonized wood blocks again in silane-modified solution and finally drying them. This invention also relates to a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge and its applications. The carbon sponge prepared by this invention has high oil absorption capacity, good reusability, low preparation cost, simple process, and easy operation, belonging to the field of adsorption materials.

Description

Technical Field

[0001] This invention relates to the field of adsorbent materials, specifically to a method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge, and also to the application of such a sponge. Background Technology

[0002] Due to increasing environmental concerns and the demands of the petroleum industry, effective oil-water separation is of paramount importance. Commonly used methods for separating oil-water mixtures, such as skimming, centrifugation, microbial degradation, and various polymer physical adsorption methods, suffer from high costs, low removal rates, discontinuous operation, and secondary pollution. To overcome these drawbacks, researchers have developed several advanced functional materials with superhydrophobic properties and special structures for oil-water separation, such as polyvinyl alcohol aerogel and titanium dioxide-coated polyurethane sponges. However, due to the high viscosity of crude oil, the capillary force of the adsorption channels in conventional porous adsorption materials is insufficient to allow crude oil to penetrate, making it difficult for these materials to successfully adsorb crude oil. For the adsorption of heavy crude oil, self-heating adsorption materials are currently widely used. These materials can effectively reduce the viscosity of crude oil at the surface contact point, achieving viscosity-reducing adsorption. Examples include PDMS / PDA-coated melamine sponges based on photothermal conversion and reduced graphene oxide-coated melamine sponges based on the Joule heating effect. However, the preparation of these materials requires complex and laborious experimental procedures and expensive equipment. Moreover, the synthesized superhydrophobic materials are non-renewable and non-biodegradable, which limits their practical application in oil-water separation.

[0003] With the development of adsorption material research, green and environmentally friendly oil-absorbing materials have attracted increasing attention. Among these, using abundant biomass materials from nature as raw materials for oil-absorbing materials has become a research hotspot in recent years. For example, CN107778523A discloses a petroleum adsorption and degradation material and its preparation method, wherein the material is a modified cellulose aerogel composite material. However, the material prepared in this scheme has poor adsorption effect on high-viscosity crude oil and the material is not recyclable.

[0004] Therefore, there is an urgent need to develop new, low-cost, multifunctional, and recyclable superhydrophobic materials for practical crude oil adsorption. Summary of the Invention

[0005] In view of the technical problems existing in the prior art, the purpose of this invention is to provide a method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge, so as to solve the problems that the adsorption effect of the adsorbent material in the prior art is not ideal and that it cannot be recycled.

[0006] Another objective of this invention is to provide a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge with high oil absorption, good reusability, low preparation cost, simple process, and easy operation.

[0007] Another objective of this invention is to provide an application of a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge includes the following steps:

[0010] (1) Cut the wood into pieces;

[0011] (2) Soak the wood blocks in boiling alkaline solution;

[0012] (3) Soak the wood blocks treated in step (2) in hydrogen peroxide solution;

[0013] (4) Dry the wood blocks to remove the moisture from the wood;

[0014] (5) Soak the dried wood blocks in a silane-modified solution;

[0015] (6) The modified wood blocks treated in step (5) are dried and then carbonized.

[0016] (7) The carbonized wood blocks are soaked again in silane-modified solution and then dried.

[0017] Preferably, in step (1), the wood block is balsa wood (light wood), and the block size is 10mm*10mm*10mm.

[0018] Preferably, in step (2), the alkaline solution includes sodium hydroxide and sodium sulfite, with mass concentrations of 10 wt.% and 5 wt.% respectively, and the soaking time is 7 h.

[0019] Preferably, in step (3), the mass concentration of the hydrogen peroxide solution is 10 wt.%, and the treatment temperature is 80°C.

[0020] Preferably, in step (4), the drying method is freeze drying, the drying temperature is -56℃, and the drying time is 36h.

[0021] Preferably, in step (5), the silane modification solution is a dodecyltrimethoxysilane solution with a mass concentration of 3 wt.% and the soaking time is 1.5 h.

[0022] Preferably, in step (6), the carbonization process is as follows: the wood block is placed in a tube furnace and heated from room temperature to 900°C at a heating rate of 8°C / min in an argon atmosphere, and held at that temperature for 6 hours.

[0023] Preferably, in step (7), the silane modification solution is a dodecyltrimethoxysilane solution with a mass concentration of 3 wt.%, and the soaking time is 3 h.

[0024] A self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge is prepared using a method for producing such a sponge.

[0025] The application of a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge as an adsorbent for crude oil.

[0026] The present invention has the following advantages:

[0027] 1. This invention uses balsa wood as raw material, which is abundant, sustainable, and low in cost.

[0028] 2. The preparation process of the present invention is simple, easy to operate, and low in cost. The silanization modification before carbonization successfully forms a polysiloxane coating on the wood surface, which well maintains the integrity of the wavy layered structure of the wood-based carbon sponge, enhances the mechanical strength of the carbon sponge, and can remain undamaged after multiple cyclic compression tests.

[0029] 3. After high-temperature carbonization, the wood-based carbon sponge tends to become graphitized, exhibiting excellent light absorption capabilities. This material can generate heat under sunlight or when powered on, thus achieving successful adsorption of crude oil.

[0030] 4. The wood-based carbon sponge prepared by this invention has a wavy layered structure. The arched structure of the wavy layers and the synergistic effect between the layers enable compression and rebound perpendicular to the direction of the wavy layers. Furthermore, after 100 cycles of compression and release at a compression rate of 50%, almost no plastic deformation occurs.

[0031] 5. The method of the present invention can realize the mass production of high-quality oil-absorbing materials and enable large-scale application. Attached Figure Description

[0032] Figure 1 This is a SEM image of the cross-section of the adsorbent material prepared in Example 1.

[0033] Figure 2 This is a SEM image of the cross-section of the adsorbent material prepared in Example 4.

[0034] Figure 3 SEM image of the cross-section of the adsorbent material prepared in Comparative Example 1.

[0035] Figure 4Cyclic compressive stress-strain curves of the adsorbent material prepared in Example 4.

[0036] Figure 5 The water contact angle is for the adsorbent material prepared in Example 4. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0038] All raw materials involved in this invention can be purchased directly from the market. For process parameters not specifically specified, conventional techniques can be used as a reference.

[0039] The raw material used in the examples and comparative examples was balsa wood; the main reagents involved were sodium hydroxide, sodium sulfite, hydrogen peroxide, and dodecyltrimethoxysilane, all of which were purchased from Shanghai Maclean Biochemical Reagent Co., Ltd.

[0040] Example 1

[0041] Wood was cut into 10mm*10mm*10mm blocks. The wood blocks were soaked in a boiling mixed solution of 10wt.% sodium hydroxide and 5wt.% sodium sulfite for 4 hours, rinsed with deionized water, and then soaked in a 10wt.% hydrogen peroxide solution at 80℃ until the wood blocks turned completely white. The white wood blocks were freeze-dried at -56℃ for 36 hours to remove moisture. The dried wood blocks were then soaked in 3wt.% dodecyltrimethoxysilane for 1.5 hours. After drying, the wood blocks were placed in a tube furnace and heated from room temperature to 600℃ at a rate of 8℃ / min in an argon atmosphere and held at that temperature for 6 hours. Finally, the carbonized wood blocks were soaked in 3wt.% dodecyltrimethoxysilane for 3 hours to obtain a hydrophobic and oleophilic wood-based adsorbent material.

[0042] Example 2

[0043] Wood was cut into 10mm*10mm*10mm blocks. The wood blocks were soaked in a boiling solution of 10wt.% sodium hydroxide and 5wt.% sodium sulfite for 5 hours, rinsed with deionized water, and then soaked in a 10wt.% hydrogen peroxide solution at 80℃ until the wood blocks turned completely white. The white wood blocks were freeze-dried at -56℃ for 36 hours to remove moisture. The dried wood blocks were then soaked in 3wt.% dodecyltrimethoxysilane for 1.5 hours. After drying, the wood blocks were placed in a tube furnace and heated from room temperature to 700℃ at a rate of 8℃ / min in an argon atmosphere and held at that temperature for 6 hours. Finally, the carbonized wood blocks were soaked in 3wt.% dodecyltrimethoxysilane for 3 hours to obtain a hydrophobic and oleophilic wood-based adsorbent material.

[0044] Example 3

[0045] Wood was cut into 10mm*10mm*10mm blocks. The wood blocks were soaked in a boiling mixed solution of 10wt.% sodium hydroxide and 5wt.% sodium sulfite for 6 hours, rinsed with deionized water, and then soaked in a 10wt.% hydrogen peroxide solution at 80℃ until the wood blocks turned completely white. The white wood blocks were freeze-dried at -56℃ for 36 hours to remove moisture. The dried wood blocks were then soaked in 3wt.% dodecyltrimethoxysilane for 1.5 hours. After drying, the wood blocks were placed in a tube furnace and heated from room temperature to 800℃ at a rate of 8℃ / min under an argon atmosphere and held at that temperature for 6 hours. Finally, the carbonized wood blocks were soaked in 3wt.% dodecyltrimethoxysilane for 3 hours to obtain a hydrophobic and oleophilic wood-based adsorbent material.

[0046] Example 4

[0047] The wood was cut into 10mm*10mm*10mm blocks. The wood blocks were soaked in a boiling mixed solution of 10wt.% sodium hydroxide and 5wt.% sodium sulfite for 7 hours, rinsed with deionized water, and then soaked in a 10wt.% hydrogen peroxide solution at 80℃ until the wood blocks turned completely white. The white wood blocks were freeze-dried at -56℃ for 36 hours to remove moisture. The dried wood blocks were then soaked in 3wt.% dodecyltrimethoxysilane for 1.5 hours. After drying, the wood blocks were placed in a tube furnace and heated from room temperature to 900℃ at a rate of 8℃ / min in an argon atmosphere and held at that temperature for 6 hours. Finally, the carbonized wood blocks were soaked in 3wt.% dodecyltrimethoxysilane for 3 hours to obtain a compressible, resilient, hydrophobic, and oleophilic wood-based carbon sponge.

[0048] Comparative Example 1

[0049] The wood is cut into 10mm*10mm*10mm blocks; the wood blocks are soaked in a boiling mixed solution of 10wt.% sodium hydroxide and 5wt.% sodium sulfite for 7 hours, rinsed with deionized water, and then soaked in a 10wt.% hydrogen peroxide solution at 80℃ until the wood blocks turn completely white. The white wood blocks are then freeze-dried at -56℃ for 36 hours to remove moisture from the wood. The dried wood blocks are then soaked in 3wt.% dodecyltrimethoxysilane for 3 hours to obtain a compressible, resilient, hydrophobic, and oleophilic sponge.

[0050] Comparative Example 2

[0051] The wood was cut into 10mm*10mm*10mm blocks; the wood blocks were soaked in a boiling mixed solution of 10wt.% sodium hydroxide and 5wt.% sodium sulfite for 7 hours, rinsed with deionized water, and then soaked in a 10wt.% hydrogen peroxide solution at 80℃ until the wood blocks turned completely white. The white wood blocks were freeze-dried at -56℃ for 36 hours to remove moisture from the wood. The dried wood blocks were placed in a tube furnace and heated from room temperature to 900℃ at a rate of 8℃ / min in an argon atmosphere and held at that temperature for 6 hours. Finally, the carbonized wood blocks were soaked in 3wt.% dodecyltrimethoxysilane for 3 hours.

[0052] The adsorbent materials prepared in Examples 1-4 and Comparative Examples 1-2 were tested for crude oil adsorption capacity under simulated sunlight. The test results are shown in Table 1.

[0053] Table 1 shows the adsorption capacity of crude oil by the adsorbent materials prepared in Examples 1-4 and Comparative Examples 1-2.

[0054]

[0055] Table 2. Surface temperatures of the adsorbent materials prepared in Examples 1-4 and Comparative Examples 1-2 under light irradiation conditions.

[0056]

[0057] Table 3 shows the surface temperature of the adsorbent materials prepared in Examples 1-4 and Comparative Examples 1-2 under a 6V voltage applied at both ends.

[0058]

[0059] Table 1 shows that the adsorption effects of the adsorbent materials prepared in Examples 1, 2, 3, and 4 on petroleum increased sequentially, and were significantly higher than those in Comparative Example 1. This indicates that with increasing soaking time in boiling alkaline solution, lignin and hemicellulose were removed more completely, resulting in a more complete wavy layered structure, which is beneficial for crude oil adsorption. Table 2 shows that after high-temperature carbonization, the carbonized wood converts sunlight into heat energy, effectively improving its adsorption capacity for crude oil. Furthermore, the higher the carbonization temperature, the stronger the light absorption and the higher the surface temperature. Simultaneously, with increasing carbonization temperature, the graphitization degree of the wood-based carbon sponge increases, improving conductivity and leading to a rise in material temperature under energized conditions. This is a crucial reason why crude oil can be successfully adsorbed. The uncarbonized comparative example, however, lacks both photothermal and electrothermal conversion capabilities.

[0060] The wood-based carbon sponge adsorbent materials prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to 100 cycles of compression testing at 50% strain, and their height loss was calculated. The results are shown in Table 4.

[0061] Table 4 shows the height loss of the adsorbent materials prepared in Examples 1-4 and Comparative Examples 1-2 after 100 cycles of cyclic compression.

[0062]

[0063] As shown in Table 4, with increasing soaking time in boiling alkaline solution, lignin and hemicellulose are removed more completely, resulting in a more complete wavy layered structure and better compression resilience. Compared to Comparative Example 2, Examples 1, 2, 3, and 4 successfully formed a polysiloxane coating on the wood surface through silanization modification before carbonization treatment, which effectively protected the wood structure, enhanced the mechanical strength of the carbon sponge, and prevented damage after multiple cyclic compression tests.

[0064] Depend on Figure 1 , Figure 2 , Figure 3 It can be seen that as the soaking time in boiling alkaline solution increases, lignin and hemicellulose are removed more completely, resulting in a more perfect wavy layered structure. Figure 4 The stress-strain curves of the wood-based carbon sponge under 100 cycles of compression at 50% compression rate are shown, demonstrating that the material has good compressive resilience. Figure 5 The water contact angle of the wood-based carbon sponge is shown, indicating that the material has good hydrophobic properties.

[0065] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge, characterized in that, Includes the following steps: (1) The wood is cut into pieces; the wood is balsa wood. (2) Soak the wood block in boiling alkaline solution, which includes sodium hydroxide and sodium sulfite; (3) Soak the wood blocks treated in step (2) in hydrogen peroxide solution; (4) Freeze-dry the wood blocks to remove moisture from the wood; (5) Soak the dried wood blocks in a silane-modified solution, wherein the silane-modified solution is a dodecyltrimethoxysilane solution; (6) The modified wood blocks treated in step (5) are dried and then carbonized. (7) The carbonized wood blocks are soaked again in silane modification solution and then dried to obtain carbon sponge, wherein the silane modification solution is dodecyltrimethoxysilane solution.

2. The method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 1, characterized in that, In step (1), the size of the cut pieces is 10mm*10mm*10mm.

3. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 1, characterized in that, In step (2), the alkaline solution includes sodium hydroxide and sodium sulfite, with mass concentrations of 10 wt.% and 5 wt.% respectively, and the soaking time is 4-7 h.

4. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 1, characterized in that, In step (3), the mass concentration of hydrogen peroxide solution is 10 wt.%, and the treatment temperature is 80 °C.

5. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 1, characterized in that, In step (4), the drying temperature is -56℃ and the drying time is 36h.

6. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 1, characterized in that, In step (5), the silane modification solution is a dodecyltrimethoxysilane solution with a mass concentration of 3 wt.%, and the soaking time is 1.5 h.

7. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 1, characterized in that, In step (6), the carbonization process is as follows: the wood block is placed in a tube furnace and heated from room temperature to 600-900℃ in an argon atmosphere at a heating rate of 8℃ / min, and held at that temperature for 6 hours.

8. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 1, characterized in that: In step (7), the silane modification solution is a dodecyltrimethoxysilane solution with a mass concentration of 3 wt.%, and the soaking time is 3 h.

9. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 3, characterized in that: In step (2), the soaking time is 7 hours.

10. A method for preparing a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 7, characterized in that: The temperature was increased from room temperature to 900℃ at a heating rate of 8℃ / min.

11. A self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge, characterized in that, The self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge is prepared using any one of claims 1 to 8.

12. The application of a self-heating, wood-based, compressible, resilient, hydrophobic, and oleophilic carbon sponge according to claim 11, characterized in that: Used as an adsorbent for crude oil.

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