Modified graphite felt with electro-thermal and photo-thermal dual response characteristics, preparation method and application thereof

Abstract

The application discloses modified graphite felt with electric heating and photothermal dual response characteristics, a preparation method and application, and comprises a graphite felt matrix, a graphitized multi-walled carbon nanotube conductive photothermal layer loaded on the surface of the graphite felt matrix, and a hydrophobic layer wrapped on the outer surface of the conductive photothermal layer. The composite material has high efficient electric heating conversion and photothermal conversion capacity, can rapidly heat up under power supply and / or illumination to reduce the viscosity of high-viscosity oil, has stable super-hydrophobic characteristics, can realize efficient and selective separation of an oil-water mixture, and is suitable for oil spill recovery in a complex environment, especially in weak light or no light conditions.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and relates to modified graphite felt with dual electrothermal and photothermal response characteristics, its preparation method, and its application. Background Technology

[0002] With the continuous expansion of offshore oil and gas development and the petrochemical industry, oil spills and oily wastewater discharge pose a serious threat to the ecological environment. In particular, high-viscosity crude oil, due to its poor fluidity and easy adhesion, generally suffers from problems such as low adsorption rate, difficult regeneration, and easy secondary pollution in the treatment process of traditional adsorption materials. There is an urgent need to develop oil-water separation functional materials with active heating and viscosity reduction capabilities.

[0003] Graphite felt (GF) has potential applications in electrothermal / photothermal assisted oil-water separation due to its three-dimensional porous network structure, good electrical conductivity, and chemical stability. However, the surface of raw graphite felt exhibits hydrophilic and oleophobic properties, making it difficult to selectively adsorb the oil phase. Furthermore, its photothermal conversion efficiency is limited, which cannot effectively meet the requirements for rapid separation of high-viscosity crude oil.

[0004] To improve surface selectivity, polydimethylsiloxane (PDMS) is often used to construct superhydrophobic surfaces due to its low surface energy and chemical inertness. However, single PDMS coatings have weak adhesion to the substrate and are prone to peeling off under long-term use or mechanical friction conditions. Furthermore, PDMS itself does not have photothermal or electrothermal functions, making it difficult to achieve active viscosity reduction.

[0005] Graphitized multi-walled carbon nanotubes (GMWCNTs) possess excellent photothermal conversion capabilities and thermal and electrical conductivity, making them ideal functional fillers for improving the heating efficiency of composite materials. However, due to their high specific surface area and strong van der Waals forces, GMWCNTs are prone to agglomeration in the matrix, affecting their performance. Achieving uniform and stable loading of GMWCNTs on the surface of three-dimensional porous flexible substrates, and on this basis, endowing the material with long-lasting hydrophobic properties, remains a challenge in current fabrication processes.

[0006] In summary, how to simultaneously achieve efficient photothermal / electrothermal conversion capabilities and durable superhydrophobic properties while maintaining the advantages of the three-dimensional porous framework of graphite felt, and also taking into account the scalability of the fabrication process, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a modified graphite felt with dual electrothermal and photothermal response characteristics. The resulting material has both high-efficiency electrothermal conversion and photothermal conversion capabilities. It can rapidly heat up under electricity or light to reduce the viscosity of high-viscosity oil. At the same time, it has stable superhydrophobic properties and can achieve efficient selective separation of oil-water mixtures. It is suitable for oil spill recovery in complex environments, especially under weak light or no light conditions.

[0008] A first aspect of the present invention is to provide a modified graphite felt with dual electrothermal and photothermal response characteristics, comprising a graphite felt matrix, a graphitized multi-walled carbon nanotube conductive and photothermal layer loaded on the surface of the graphite felt matrix, and a hydrophobic layer wrapped around the outer surface of the conductive and photothermal layer.

[0009] A second aspect of the present invention is to provide a method for preparing the modified graphite felt with dual electrothermal and photothermal response characteristics, comprising the following steps: S1: Graphitized multi-walled carbon nanotubes and dispersant polyvinylpyrrolidone were added to anhydrous ethanol and a uniform dispersion was prepared by ultrasonic dispersion treatment. S2: Immerse the graphite felt matrix in the dispersion obtained in step S1, sonicate it, let it stand, fully impregnate it, and then take it out and dry it to obtain graphite felt loaded with graphitized multi-walled carbon nanotubes. S3: The graphite felt material obtained in step S2 is impregnated with polydimethylsiloxane (PDMS) solution and cured to obtain a graphitized multi-walled carbon nanotube / graphite felt composite material encapsulated with PDMS.

[0010] In one optional embodiment, in step S1, the mass ratio of graphitized multi-walled carbon nanotubes to polyvinylpyrrolidone is 20:1 to 30:1.

[0011] In one optional embodiment, in step S2, the ultrasound time is 2 to 10 minutes and the settling time is 1 to 2 hours.

[0012] In one optional embodiment, in step S2, the soaking time is 30–90 min, the drying temperature is 70–100°C, and the drying time is 2–4 h.

[0013] In one optional embodiment, in step S3, the curing temperature is 80–110°C and the curing time is 2–4 h.

[0014] In an optional embodiment, in step S3, the concentration of the polydimethylsiloxane PDMS solution is 0.5 to 2 wt%.

[0015] A third aspect of the present invention is to provide an application of the modified graphite felt with dual electrothermal and photothermal response characteristics in the adsorption and / or oil-water separation of high-viscosity crude oil driven by photothermal / electrothermal processes.

[0016] Compared with the prior art, the technical solution of the present invention has the following advantages: 1. The material of this invention has dual heating capabilities of electrothermal and photothermal modes. It can be heated rapidly by electricity or by light, adapting to different environmental conditions to achieve all-weather oil-water separation. At the same time, it can reduce the viscosity of high-viscosity crude oil under both light and electrothermal conditions, achieving efficient adsorption and oil-water separation. The PDMS encapsulation process gives the material a stable superhydrophobic surface with a water contact angle greater than 150°, significantly improving oil-water selectivity and anti-fouling ability.

[0017] 2. The composite material achieves a rapid adsorption rate by utilizing the abundant oil adsorption channels provided by the three-dimensional porous structure of graphite felt (GF) and the abundant adsorption sites provided by the high specific surface area of ​​GMWCNTs.

[0018] 3. Utilizing the one-dimensional high aspect ratio structure of carbon nanotubes, and a three-dimensional interconnected woven framework of graphite felt, through homologous sp... 2 carbon materials Conjugate physical anchoring can simultaneously achieve functions such as filling fiber gaps to reconstruct the transmission network, constructing a non-blocking hierarchical porous structure, forming a continuous and stable wettability control network, and bridging fibers, thereby improving the mechanical properties of composite materials while also meeting the needs of low-cost and scalable industrialization.

[0019] 4. The preparation process is simple, requires no complex equipment, has mild reaction conditions, is easy to scale up, and has good application prospects. Attached Figure Description

[0020] Figure 1 The images show SEM images of the photothermal / electrothermal graphite felt composite material PDMS-CNTs-GF and unmodified graphite felt of the present invention.

[0021] Figure 2 This is a water contact angle test diagram of the photothermal / electrothermal graphite felt composite material PDMS-CNTs-GF of the present invention.

[0022] Figure 3 This is an experimental diagram showing the oil-water separation of the photothermal / electrothermal graphite felt composite material PDMS-CNTs-GF in a gravity-driven device.

[0023] Figure 4 This is a graph showing the oil-water separation efficiency of the photothermal / electrothermal graphite felt composite material PDMS-CNTs-GF after 10 cycles of use.

[0024] Figure 5 The graph shows the photothermal heating curve of the photothermal / electrothermal graphite felt composite material PDMS-CNTs-GF under one solar intensity and the photothermal stability test graph after five heating and cooling cycles.

[0025] Figure 6The electrothermal heating curve of the photothermal / electrothermal graphite felt composite material PDMS-CNTs-GF of the present invention is shown at 1.5V. Figure 5 Electrothermal stability test diagram for repeated heating and cooling.

[0026] Figure 7 This is a schematic diagram of the adsorption process of high-viscosity crude oil by the photothermal / electrothermal graphite felt composite material PDMS-CNTs-GF under light irradiation.

[0027] Figure 8 This is a schematic diagram of the adsorption process of high-viscosity crude oil by the photothermal / electrothermal composite graphite felt PDMS-CNTs-GF under electrothermal conditions according to the present invention.

[0028] Figure 9 This is a schematic diagram illustrating the adsorption process of high-viscosity crude oil by the photothermal / electrothermal composite graphite felt PDMS-CNTs-GF under the synergistic effect of photothermal and electrothermal processes of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0030] Example 1 A modified graphite felt with dual electrothermal and photothermal response characteristics is prepared by the following steps: (1) Preparation of graphitized multi-walled carbon nanotube dispersion Weigh 50 mg of graphitized multi-walled carbon nanotubes (GMWCNTs) and 3 mg of polyvinylpyrrolidone (PVP), add 10 mL of anhydrous ethanol, and sonicate for 2 h to obtain a uniform dispersion of graphitized multi-walled carbon nanotubes (GMWCNTs) with a concentration of 5 mg / mL.

[0031] (2) Preparation of composite material CNTs-GF A pre-cleaned graphite felt GF (2 cm × 2 m) was immersed in the above dispersion for 60 min, then removed and dried in an oven at 90 °C for 3 h to obtain the composite material CNTs-GF.

[0032] (3) Preparation of graphite felt composite material PDMS-CNTs-GF Prepare a 2 wt% PDMS solution (PDMS prepolymer to curing agent mass ratio 10:1, dissolved in n-hexane), immerse the composite material CNTs-GF obtained in step (2) in it for 5 min, take it out and cure it at 100℃ for 3 h to obtain the graphite felt composite material PDMS-CNTs-GF.

[0033] Example 2 A modified graphite felt with dual electrothermal and photothermal response characteristics is prepared by the following steps: (1) Preparation of graphitized multi-walled carbon nanotube dispersion Weigh 30 mg of graphitized multi-walled carbon nanotubes (GMWCNTs) and 1 mg of polyvinylpyrrolidone (PVP), add 10 mL of anhydrous ethanol, and sonicate for 1.5 h to obtain a uniform dispersion of graphitized multi-walled carbon nanotubes (GMWCNTs) with a concentration of 3 mg / mL.

[0034] (2) Preparation of composite material CNTs-GF A pre-cleaned graphite felt GF (2 cm × 2 m) was immersed in the above dispersion for 40 min, then removed and dried in an oven at 80 °C for 4 h to obtain the composite material CNTs-GF.

[0035] (3) Preparation of graphite felt composite material Prepare a 0.5 wt% PDMS solution (PDMS prepolymer to curing agent mass ratio 10:1, dissolved in n-hexane), immerse the composite material CNTs-GF obtained in step (2) in it for 5 min, take it out and cure it at 80℃ for 4 h to obtain the graphite felt composite material.

[0036] Example 3 A modified graphite felt with dual electrothermal and photothermal response characteristics is prepared by the following steps: (1) Preparation of graphitized multi-walled carbon nanotube dispersion Weigh 75 mg of graphitized multi-walled carbon nanotubes (GMWCNTs) and 3 mg of polyvinylpyrrolidone (PVP), add 10 mL of anhydrous ethanol, and sonicate for 2 h to obtain a uniform dispersion of graphitized multi-walled carbon nanotubes (GMWCNTs) with a concentration of 7.5 mg / mL.

[0037] (2) Preparation of composite material CNTs-GF A pre-cleaned graphite felt GF (2 cm × 2 m) was immersed in the above dispersion for 80 min, then removed and dried in an oven at 95 °C for 2.5 h to obtain the composite material CNTs-GF.

[0038] (3) Preparation of graphite felt composite material Prepare a 1 wt% PDMS solution (PDMS prepolymer to curing agent mass ratio 10:1, dissolved in n-hexane), immerse the composite material CNTs-GF obtained in step (2) in it for 5 min, take it out and cure it at 80℃ for 2 h to obtain the graphite felt composite material.

[0039] Test Example 1 The microstructure of the graphite felt composite material PDMS-CNTs-GF prepared in Example 1 and the structure of the graphite felt (GF) substrate were observed using scanning electron microscopy. The results are as follows: Figure 1 As shown. Figure 1 (a) shows the structure of the graphite felt (GF) substrate; Figure 1 (b) shows the structure of the graphite felt composite material PDMS-CNTs-GF.

[0040] from Figure 1 As can be seen in (a), the original GF substrate has a loose three-dimensional fiber interwoven porous network structure. The fiber bundles overlap to form pore channels with excellent connectivity. The pores are evenly distributed, and the surface of a single graphite fiber is relatively flat and smooth, providing a stable substrate support and smooth path for the loading of functional components of graphitized multi-walled carbon nanotubes (GMWCNTs) and subsequent fluid transport.

[0041] from Figure 1 (b) As can be seen, after loading GMWCNTs functional layers and modifying the surface with PDMS, the graphite fiber surface and pore inner walls of the graphite felt composite material are covered with a nanoscale composite coating. The integrity of the original three-dimensional porous network structure is preserved, with only a slight reduction in some pore sizes and a significant roughening of the fiber surface morphology. Local high-magnification images show that tubular nanostructures (corresponding to the typical one-dimensional morphology of GMWCNTs) are uniformly wrapped around the fiber surface, providing more adsorption sites. PDMS, as a binder and coating phase, further anchors GMWCNTs firmly and uniformly to the GF substrate surface and pore walls, while filling the tiny gaps between GMWCNTs, forming a continuous, stable, and tightly bonded functionalized modified layer.

[0042] Test Example 2 The wettability of the graphite felt composite material PDMS-CNTs-GF was characterized by water contact angle testing. The tests were conducted at room temperature using a contact angle meter.

[0043] The graphite felt composite material was stably placed on the sample stage of the contact angle measuring instrument. At room temperature and atmospheric pressure, 5 μL of deionized water was added to the membrane surface using the seated drop method. After the water droplet morphology stabilized (approximately 30 seconds), five test points were selected in different areas of the membrane surface for repeated measurements, and the average value was taken as the final data. The results are as follows: Figure 2 As shown.

[0044] from Figure 2As can be seen, the water contact angle of the graphite felt composite material can reach 150°, demonstrating its typical superhydrophobic properties. This characteristic can effectively hinder the spread and penetration of water molecules, laying a key foundation for efficient oil-water selective separation. Furthermore, after being soaked in acidic and alkaline solutions with different pH values ​​(3 and 12) and a high-concentration salt solution of 0.5wt% NaCl for 24 hours, the water contact angle of the graphite felt composite material still remained above 150°, maintaining stable superhydrophobic properties and demonstrating excellent environmental tolerance and practical application potential.

[0045] Test Example 3 The oil-water separation process of the graphite felt composite material PDMS-CNTs-GF was demonstrated using a simple gravity-driven device.

[0046] Carbon tetrachloride and deionized water were mixed evenly at a volume ratio of 1:2 to prepare an oil-water mixture. The composite graphite felt was cut to a suitable size and sealed and fixed to the filter membrane support of the gravity-driven separation device. The mixture was slowly poured into the inlet, flowing through the composite graphite felt under gravity. The results are as follows... Figure 3 As shown, during the separation process, the oil phase can quickly pass through the membrane layer and collect in the collection bottle below, while the water phase is effectively blocked and rolls off the membrane surface in a spherical shape, achieving efficient separation of the oil and water phases.

[0047] The separation efficiency was tested after the graphite felt composite material was continuously recycled 10 times, and the results are as follows: Figure 4 As shown, its oil-water separation efficiency remains stable at over 96%, which fully demonstrates that the material not only has high separation efficiency, but also excellent operational stability and durability for repeated use, and can meet the requirements of actual oily wastewater treatment for material life.

[0048] Test Example 4 The photothermal properties and stability of the graphite felt composite material PDMS-CNTs-GF were investigated.

[0049] Graphite felt composite material was cut into 2 cm × 2 cm samples and placed horizontally on a heat-insulating platform. A simulated sunlight source (light intensity 1 kW / m², equivalent to one sun) was used to vertically irradiate blank graphite felt and the graphite felt composite material PDMS-CNTs-GF (Example 1). An infrared thermometer was used to record the surface temperature change with irradiation time in real time. The stability of the graphite felt composite material PDMS-CNTs-GF was tested by repeating the "light-heating-cooling" cycle, continuously monitoring for 17.5 minutes, and recording the temperature change trend for each cycle. The results are as follows: Figure 5 As shown.

[0050] from Figure 5As shown in (a), under one solar irradiation, the blank graphite felt started to heat up from room temperature (approximately 20°C), reaching a maximum temperature of about 74°C in 90 seconds; while the graphite felt composite material started to heat up from room temperature (approximately 20°C), reaching a maximum temperature of about 90°C in 90 seconds; after the irradiation stopped (approximately 120 seconds), the temperature of both materials gradually cooled to around 30°C. These results confirm that GMWCNTs can enhance the photothermal effect of the GF substrate. GMWCNTs efficiently capture sunlight and convert it into heat energy, the three-dimensional porous skeleton of the graphite felt accelerates uniform heat conduction, and PDMS coating reduces heat loss, together achieving rapid heating and short-term isothermal photothermal performance.

[0051] from Figure 5 As shown in (b), during the 17.5-minute multiple "light-shading" cycle test, the graphite felt composite material was able to quickly rise to a high temperature range of about 70°C during each light exposure phase and stably drop back to about 30°C during the cooling phase. After multiple cycles, the maximum temperature did not decrease significantly, and the heating rate was basically the same as that of the initial cycle, proving that it has excellent photothermal stability. The bonding and coating effect of PDMS can prevent GMWCNTs from falling off or agglomerating during the light exposure cycle, ensuring long-term stability of photothermal performance and making it suitable for long-term outdoor light exposure conditions.

[0052] Test Example 5 The electrothermal properties and stability of the graphite felt composite material PDMS-CNTs-GF were investigated.

[0053] Blank graphite felt and graphite felt composite materials were cut into 2 cm × 2 cm samples and placed horizontally on a heat-insulating platform. Electrodes were led out at both ends through conductive silver paste and connected to a DC regulated power supply. A constant working voltage of 1.5V was set, and the surface temperature change with the energizing time was recorded in real time using an infrared thermometer. The stability test was performed by repeating the "energizing-heating-cooling" cycle (each cycle includes energizing, isothermal, and cooling stages), for a total of 5 cycles. The highest temperature and temperature change trend of each cycle were recorded. The results are as follows: Figure 6 As shown.

[0054] from Figure 6As shown in (a), under a constant low voltage of 1.5V, the surface temperature of the graphite felt composite material rapidly rises from room temperature (approximately 20℃) to about 80℃ within 30 seconds, with a heating rate of 2℃ / s. After approximately 90 seconds of energization, it remains above 85℃, reaching a temperature as high as 90℃, demonstrating efficient electrothermal heating and temperature control capabilities. In contrast, the surface temperature of the blank graphite felt rapidly rises from room temperature (approximately 20℃) to about 70℃ within 30 seconds, with a heating rate of 1.6℃ / s. After approximately 90 seconds of energization, it remains around 75℃, showing a smaller temperature change. This result confirms the synergistic electrical and thermal conductivity effect of GMWCNTs combined with the GF substrate. The excellent conductivity of GMWCNTs allows current to pass uniformly through the film, rapidly converting electrical energy into heat energy through the Joule heating effect. The three-dimensional porous skeleton of the graphite felt accelerates heat conduction and diffusion, while the PDMS coating reduces heat loss without affecting conductivity, further enhancing the electrothermal conversion efficiency.

[0055] from Figure 6 As shown in (b), after five "power-on-cool" cycle tests (completed within 10 minutes), the composite graphite felt maintained a stable maximum temperature above 85°C at 1.5V, with a temperature drop of less than 1% per cycle. The heating rate and the duration of high-temperature maintenance showed no significant decrease, fully demonstrating its excellent electrothermal stability. A stable structure is key to long-term performance maintenance: PDMS firmly anchors GMWCNTs to the surface of the graphite felt fibers, preventing GMWCNTs from falling off, agglomerating, or causing poor electrode contact during power-on cycles. The graphite felt skeleton structure ensures long-term stability of the conductive path, providing reliable support for complex working conditions without light, such as in darkness or underground environments.

[0056] Test Example 6 The adsorption effects of the graphite felt composite material PDMS-CNTs-GF (Example 1) on high-viscosity crude oil under light, electrothermal, and photothermal / electrothermal synergy were investigated.

[0057] 0.2g of solid crude oil was selected as the treatment object; graphite felt composite material was cut into 2 cm × 2 cm samples and fixed in a customized testing device; a simulated sunlight source (light intensity 1 kW / m²), a voltage of 1.5 V, and simultaneously applying one sunlight source and a voltage of 1.5 V were used to record the rate of crude oil adsorption. The results are as follows: Figure 7 , Figure 8 as well as Figure 9 As shown.

[0058] from Figure 7As can be seen from the data, under illumination, the surface temperature of the graphite felt composite material rapidly increases due to the synergistic photothermal effect of GMWCNTs and the GF substrate. The viscosity of the crude oil at the contact points decreases significantly after localized heating, and its fluidity is greatly enhanced, allowing for rapid adsorption. High-viscosity crude oil can be completely adsorbed within 90 seconds. This indicates that the graphite felt composite material can actively reduce the viscosity of high-viscosity crude oil using solar energy and adsorb it efficiently, effectively overcoming the technical bottleneck of slow adsorption rate and low recovery efficiency caused by the poor fluidity of traditional adsorption materials. Furthermore, PDMS coating modification endows the material with excellent hydrophobic and oleophilic properties, further enhancing its selective adsorption capacity for crude oil. Simultaneously, its strong bonding effect prevents GMWCNTs from easily detaching during long-term illumination and adsorption-desorption cycles, providing a reliable guarantee for the efficient and stable treatment of high-viscosity crude oil.

[0059] from Figure 8 As can be seen, under the condition of 1.5 V electric heating, the material can achieve efficient adsorption within 80 s, which is 10 s shorter than that under light conditions.

[0060] from Figure 9 As can be seen, under the combined conditions of one sunlight and 1.5 V photothermal and electrothermal, the material can achieve efficient adsorption within 30 s. Compared with the adsorption time under light and electrothermal conditions, the adsorption time is shortened by 60 s and 50 s respectively, and its adsorption efficiency is significantly improved.

[0061] Although the present invention has been described using the above preferred embodiments, it is not intended to limit the scope of protection of the present invention. Any changes and modifications made by those skilled in the art to the above embodiments without departing from the spirit and scope of the present invention shall still fall within the scope of protection of the present invention.

Claims

1. A modified graphite felt possessing dual electrothermal and photothermal response characteristics, characterized in that, It includes a graphite felt substrate, a graphitized multi-walled carbon nanotube conductive photothermal layer loaded on the surface of the graphite felt substrate, and a hydrophobic layer wrapped around the outer surface of the conductive photothermal layer.

2. A method for preparing the modified graphite felt with dual electrothermal and photothermal response characteristics as described in claim 1, characterized in that, Includes the following steps: S1: Graphitized multi-walled carbon nanotubes and dispersant polyvinylpyrrolidone were added to anhydrous ethanol and a uniform dispersion was prepared by ultrasonic dispersion treatment. S2: Immerse the graphite felt matrix in the dispersion obtained in step S1, sonicate it, let it stand, fully impregnate it, and then take it out and dry it to obtain graphite felt loaded with graphitized multi-walled carbon nanotubes. S3: The graphite felt material obtained in step S2 is impregnated with polydimethylsiloxane (PDMS) solution and cured to obtain a graphitized multi-walled carbon nanotube / graphite felt composite material encapsulated with PDMS.

3. The method for preparing the modified graphite felt with dual electrothermal and photothermal response characteristics according to claim 2, characterized in that, In step S1, the concentration of graphitized multi-walled carbon nanotubes is 2–10 mg / ml.

4. The method for preparing the modified graphite felt with dual electrothermal and photothermal response characteristics according to claim 2, characterized in that, In step S1, the mass ratio of graphitized multi-walled carbon nanotubes to polyvinylpyrrolidone is 20:1 to 30:

1.

5. The method for preparing the modified graphite felt with dual electrothermal and photothermal response characteristics according to claim 2, characterized in that, In step S2, the ultrasound time is 2 to 10 minutes and the settling time is 1 to 2 hours.

6. The method for preparing the modified graphite felt with dual electrothermal and photothermal response characteristics according to claim 2, characterized in that, In step S2, the soaking time is 30-90 min, the drying temperature is 70-100℃, and the drying time is 2-4 h.

7. The method for preparing the modified graphite felt with dual electrothermal and photothermal response characteristics according to claim 2, characterized in that, In step S3, the curing temperature is 80–110°C and the curing time is 2–4 h.

8. The method for preparing the modified graphite felt with dual electrothermal and photothermal response characteristics according to claim 2, characterized in that, In step S3, the concentration of the polydimethylsiloxane PDMS solution is 0.5–2 wt%.

9. The application of the modified graphite felt with dual electrothermal and photothermal response characteristics as described in claim 1 in the adsorption and recovery of high-viscosity crude oil or oil-water separation driven by photothermal and / or electrothermal processes.

Images