Photo-thermal oil absorption material with graded capillary network and preparation method of photo-thermal oil absorption material

Abstract

The invention discloses a photo-thermal oil absorption material with a graded capillary network and a preparation method of the photo-thermal oil absorption material, and relates to the technical field of adsorption materials. The bi-component ethylene-propylene fiber and the collagenous fiber are compounded by adopting an in-situ thermal bonding process to obtain the photo-thermal oil absorption material, so that the collagenous fiber rich in fine capillaries in the photo-thermal oil absorption material is wound on the surface of the bi-component ethylene-propylene fiber with relatively large pores to form a graded capillary network; boron nitride nanosheets are directionally stacked and continuously anchored on the surface of the bi-component ethylene-propylene fiber to form a large-area continuous heat conduction channel, and the photothermal conversion efficiency and the heat conductivity of the photothermal oil absorption material are synergistically enhanced by adding the carbon nanoparticles; the heat on the upper surface of the photo-thermal oil absorption material is quickly transferred to an oil-material interface to reduce the viscosity of oil, so that the adsorption performance of the photo-thermal oil absorption material on the oil is further improved.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, and in particular to a photothermal oil-absorbing material with a hierarchical capillary network and its preparation method. Background Technology

[0002] In recent years, oil spills, including crude oil, have posed a serious threat to marine ecosystems, socio-economic development, and human health. To minimize the harm caused by oil spills, related technologies utilize oil-absorbing materials to effectively adsorb and recover oil floating on the water surface. Among these technologies, photothermal oil-absorbing materials (PTOA) utilize solar energy to generate localized heat to reduce the viscosity of crude oil and improve its fluidity, demonstrating excellent performance in high-viscosity crude oil removal scenarios.

[0003] The PTOA preparation methods provided by related technologies improve the oil absorption performance of PTOA products by increasing PTOA porosity. However, excessively large pores can easily lead to low PTOA density, which in turn affects the physical properties of the product. Furthermore, under the influence of factors such as the gravity and surface tension of the oil itself, single-sized pores can only adsorb oil in the shallow layer of the pores, resulting in extremely low internal pore utilization. In addition, the heat of PTOA comes from sunlight, and a large amount of heat energy is lost during the transfer of its upper surface to the oil-material interface, further affecting its adsorption performance in actual oil adsorption scenarios. Summary of the Invention

[0004] The main objective of this invention is to provide a photothermal oil-absorbing material with a hierarchical capillary network and its preparation method, thereby addressing the technical problem of low oil adsorption performance in related technologies and achieving the technical effect of improving the oil adsorption performance of photothermal oil-absorbing materials. The technical solution of this invention is as follows: According to a first aspect of the present invention, a method for preparing a photothermal oil-absorbing material having a hierarchical capillary network is provided, characterized in that the method for preparing the photothermal oil-absorbing material includes: A high-pressure pulsed water jet method is used to spray a boron nitride nanosheet dispersion onto the surface of a two-component ethylene-propylene fiber at a preset angle, so that the boron nitride nanosheets are continuously anchored to the surface of the two-component ethylene-propylene fiber along the fluid direction. After mixing the bicomponent ethylene-propylene fiber anchored with boron nitride nanosheets with collagen fiber, carbon nanoparticles are added for homogenization to obtain mixed fiber. The mass ratio of the bicomponent ethylene-propylene fiber, the collagen fiber, the carbon nanoparticles and the boron nitride nanosheets are 0.5:0.5:0.01-0.2:0.01-0.2, respectively. The mixed fibers are carded by a carding machine to obtain a mixed fiber web. The mixed fiber web is then evenly cut and fed into a flat mold of a preset size for compaction to obtain a felt-like preform. The felt-like preform is placed in a continuous hot air furnace at 140°C for 5 minutes for heat bonding treatment, then cooled to room temperature and demolded to obtain a semi-finished product of photothermal oil-absorbing material. The semi-finished photothermal oil-absorbing material is immersed in a polydimethylsiloxane / n-hexane solution for 10 minutes, then removed and dried in an oven at room temperature for 30 minutes to obtain a photothermal oil-absorbing material with a hierarchical capillary network. The mass ratio of polydimethylsiloxane to n-hexane in the polydimethylsiloxane / n-hexane solution is 0.015-0.035:1.

[0005] In a preferred embodiment, the parameters used in the high-pressure pulsed water jet method include: The nozzle diameter of the high-pressure spray gun is 2.5 mm; the pressure of the high-pressure pump is 700 bar, and the flow rate is 4 L / min; the preset angle is 25°.

[0006] In a preferred embodiment, the method for preparing the boron nitride nanosheet dispersion includes: After adding boron nitride nanosheets to deionized water, ultrasonic dispersion was performed for 30 minutes using an ultrasonic cleaner to ensure uniform dispersion of the boron nitride nanosheets, resulting in a homogeneous and stable boron nitride nanosheet dispersion.

[0007] In a preferred embodiment, the mass ratio of the bicomponent ethylene-propylene fiber, the collagen fiber, the carbon nanoparticles, and the boron nitride nanosheets is 0.5:0.5:0.2:0.17, respectively.

[0008] In a preferred embodiment, the mass ratio of polydimethylsiloxane to n-hexane in the polydimethylsiloxane / n-hexane solution is 0.025:1.

[0009] In a preferred embodiment, the pore size of each capillary channel in the hierarchical capillary network of the photothermal oil-absorbing material is 70 nm-500 µm.

[0010] In a preferred embodiment, the oil absorption rate of the photothermal oil-absorbing material is 168-256 g / (g·min).

[0011] In a preferred embodiment, the density of the photothermal oil-absorbing material is 0.027 g / cm³.

[0012] According to a second aspect of the present invention, a photothermal oil-absorbing material having a hierarchical capillary network is provided, characterized in that the photothermal oil-absorbing material is prepared by any of the above-described methods for preparing photothermal oil-absorbing materials, and the oil absorption rate of the photothermal oil-absorbing material is 168-256 g / (g·min).

[0013] Compared with existing technologies, the photothermal oil-absorbing material with a hierarchical capillary network and its preparation method provided by the present invention have the following advantages: This invention provides a photothermal oil-absorbing material with a hierarchical capillary network and its preparation method. The photothermal oil-absorbing material is obtained by in-situ thermal bonding of bicomponent ethylene-propylene fibers and collagen fibers. This allows the collagen fibers, rich in fine capillaries, to entwine around the surface of the more porous bicomponent ethylene-propylene fibers, forming a hierarchical capillary network. This accelerates the adsorption performance of the photothermal oil-absorbing material on oils. Furthermore, by directionally stacking and continuously anchoring boron nitride nanosheets onto the surface of the bicomponent ethylene-propylene fibers to form a large-area continuous thermal conduction pathway, and by adding carbon nanoparticles, the photothermal conversion efficiency and thermal conductivity of the photothermal oil-absorbing material are synergistically enhanced. This allows heat from the upper surface of the photothermal oil-absorbing material to be rapidly transferred to the oil-material interface to reduce oil viscosity, thereby further improving the adsorption performance of the photothermal oil-absorbing material on oils. Attached Figure Description

[0014] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0015] Figure 1 This is a flowchart illustrating a photothermal oil-absorbing material method with a hierarchical capillary network according to an exemplary embodiment.

[0016] Figure 2 This is a schematic diagram of the internal structure of the PTOA provided by the present invention.

[0017] Figure 3 This is a schematic diagram of the VTLF bundle morphology in the PTOA provided by the present invention.

[0018] Figure 4 This is a schematic diagram of the VTLF diameter in the PTOA provided by the present invention.

[0019] Figure 5 This is a schematic diagram of the crosslinking point distribution between ES in PTOA provided by the present invention.

[0020] Figure 6 This is a schematic diagram of the crosslinking point distribution between ES and VTLF in PTOA provided by the present invention.

[0021] Figure 7 This is a schematic diagram of the core-shell structure of the ES in the PTOA provided by the present invention.

[0022] Figure 8 This is a schematic diagram of the dispersion of CNPs in VTLF in PTOA provided by the present invention.

[0023] Figure 9This is a schematic diagram of the BNNS package on the VTLF in the PTOA provided by the present invention.

[0024] Figure 10 This is a schematic diagram of the distribution of BNNS and CNPs within the PTOA provided by the present invention.

[0025] Figure 11 This is a schematic diagram of the reconstructed three-dimensional structure of PTOA provided by the present invention.

[0026] Figure 12 This is a schematic diagram of the single-factor experimental results showing the influence of CNPs and BNNS content on the bottom temperature of PTOA provided by this invention.

[0027] Figure 13 This is a schematic diagram illustrating the effect of CNPs and BNNS content on the response surface temperature of the top surface of the PTOA provided by this invention.

[0028] Figure 14 This is a schematic diagram illustrating the effect of CNPs and BNNS content on the response surface temperature of the bottom surface of the PTOA provided by this invention. Detailed Implementation

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] For ease of reading, the English abbreviations used in the embodiments of this invention are explained below: CNPs: Carbon nanoparticles; BNNS: Boron nitride nanosheets; PTOA: Photothermal oil-absorbing material; ES: Bicomponent ethylene-propylene fiber; VTLF: Collagen fiber; RSM: Response Surface Methodology; Figure 1 This is a flowchart illustrating a photothermal oil-absorbing material method with a hierarchical capillary network according to an exemplary embodiment, as shown below. Figure 1 As shown, the method for preparing the photothermal oil-absorbing material with a hierarchical capillary network is characterized in that the method for preparing the photothermal oil-absorbing material includes: Step 100: The boron nitride nanosheet dispersion is sprayed at a preset angle onto the surface of the two-component ethylene-propylene fiber using a high-pressure pulsed water jet method, so that the boron nitride nanosheets are continuously anchored to the surface of the two-component ethylene-propylene fiber along the fluid direction.

[0031] The high-pressure pulsed water jet method employed in this invention involves spraying a boron nitride nanosheet dispersion from a high-pressure spray gun at a predetermined angle onto the surface of bicomponent ethylene-propylene fibers. Under the intense fluid shearing and instantaneous impact forces generated by the high-speed water flow, the boron nitride nanosheets in the dispersion align oriented along the fluid direction. Through physical adsorption between their surface functional groups and the surface of the bicomponent ethylene-propylene fibers, they adhere tightly to the fibers and their interlacing nodes, forming a uniform, dense boron nitride nanosheet coating layer with a biomimetic multi-level roughness structure on the surface of the bicomponent ethylene-propylene fibers. This boron nitride nanosheet coating layer exhibits a layered morphology similar to wool scales, significantly increasing the nanoscale roughness and specific surface area of ​​the fiber surface, forming continuous thermal conductivity pathways, facilitating heat transfer, and endowing the material with excellent photothermal conversion properties.

[0032] Step 200: After mixing the bicomponent ethylene-propylene fiber anchored with boron nitride nanosheets with collagen fiber, carbon nanoparticles are added for homogenization treatment to obtain mixed fiber. The mass ratio of the bicomponent ethylene-propylene fiber, the collagen fiber, the carbon nanoparticles and the boron nitride nanosheets are 0.5:0.5:0.01-0.2:0.01-0.2, respectively.

[0033] Step 300: The mixed fibers are carded by a carding machine to obtain a mixed fiber web. The mixed fiber web is then evenly cut and fed into flat molds of preset specifications for compaction to obtain a felt-like preform.

[0034] Step 400: The felt-like preform is placed in a continuous hot air furnace at 140°C for 5 minutes for heat bonding treatment, then cooled to room temperature and demolded to obtain a semi-finished product of photothermal oil-absorbing material.

[0035] Step 500: The semi-finished photothermal oil-absorbing material is immersed in a polydimethylsiloxane / n-hexane solution for 10 minutes, then removed and dried in an oven at room temperature for 30 minutes to obtain a photothermal oil-absorbing material with a hierarchical capillary network. The mass ratio of polydimethylsiloxane to n-hexane in the polydimethylsiloxane / n-hexane solution is 0.015-0.035:1.

[0036] Among them, polydimethylsiloxane / n-hexane solution is used to modify the surface of semi-finished photothermal oil-absorbing materials to make them hydrophobic, thereby further improving their adsorption efficiency for oils.

[0037] This invention employs a biomimetic approach, using a highly elastic ES (external elastic element) as a framework to simulate the rigid support of a tree trunk. This provides excellent mechanical properties for the photothermal oil-absorbing material while enhancing its elasticity and porosity, and improving oil retention. VTLF (Vibration-Temperature Lung Fiber) and ES intertwine to form a multi-scale porous network containing both fine and wide capillaries with a hierarchical pore size distribution (70nm–500µm). The VTLF, rich in fine capillaries, wraps around the ES surface like vines, generating a synergistic effect that promotes oil transport and significantly improves absorption kinetics. This can be described using a modified Washburn equation and a hierarchical wetting model. The capillary rise height h and flow velocity v are controlled by Laplace pressure. According to the Lucas-Washburn equation, the penetration distance follows the law L(t)∝r1 / 2. Larger radius capillaries are beneficial for forming a larger cross-sectional flow area, while narrower capillaries generate higher capillary pressure (P=2γcosθ / r), thus forming a local pressure gradient. In a hierarchical capillary network, oil flow does not occur in isolation but is coupled. Oil entering the nanoscale pores generates negative pressure, drawing oil into adjacent microscale pores, effectively accelerating the entire oil permeation process. These microcapillaries act as "capillary accelerators," pre-wetting the structure and forming capillary bridges, allowing oil to bypass the initial flow resistance in the macroscopic capillaries. This dynamic coupling between narrow and wide pores ensures that oil not only penetrates rapidly but also distributes more evenly and deeply within the felt-like structure. Simultaneously, intermolecular interactions play a crucial role. First, the hydrophobic and oleophilic components of the photothermal oil-absorbing material interact favorably with nonpolar oil molecules through van der Waals forces. This affinity induces oil molecules to spontaneously aggregate along the inner surface of the fiber, wetting the fiber surface—a thermodynamically spontaneous process. Subsequently, the initially attached oil molecules initiate oil-oil cascade cohesion, forming continuous molecular layers that ultimately fill the available free volume. The macroscopic absorption process finally terminates when the interfacial tension acting on the oil reaches equilibrium with the opposing gravitational force.

[0038] It is evident that the synergistic coupling of multi-scale capillary-driven absorption and molecular self-assembly endows the PTOA provided by this invention with excellent adsorption capacity and ultra-fast adsorption performance. The hierarchical capillary network constructs a continuous pressure gradient and a rapid transport channel, enabling oil molecules to quickly penetrate and diffuse through multi-scale pores. Simultaneously, driven by the synergistic effect between oil molecules, molecular self-assembly gradually transforms the available free volume into a highly ordered and stable filling region. This dual mechanism based on adsorbent-oil surface wetting and oil molecule-intermolecular interaction makes the adsorption process thermodynamically spontaneous, further accelerating the absorption rate of oils, thereby enabling PTOA to possess highly efficient oil absorption performance.

[0039] To further illustrate the internal structure of the PTOA provided by this invention, a schematic field emission scanning electron microscope (FESEM) image of the internal structure of the PTOA with a density of 0.027 g / cm³ provided by this invention is shown as follows: Figure 2-10 As shown. According to Figure 2 As shown in the schematic diagram of the internal structure of PTOA, the internal cavity size of PTOA is 100-500µm, and the diameter of ES is 26-30µm. According to... Figure 3 The diagram shows the morphology of the VTLF bundle in the PTOA and Figure 4 As shown in the schematic diagram of VTLF diameter, collagen fibers are uniformly dispersed inside PTOA. Its structure shows that the average diameter of collagen fibers is 2-5µm, and the average diameter of VTLF bundles is about 115µm. VTLF and ES together form an open cavity channel structure of 70nm to 500µm, which provides a structural basis for rapid oil absorption driven by macroscopic capillary effect controlled by Laplace pressure. Figure 5 and 6 The diagram shows the crosslinking point distribution between ES and between ES and VTLF in PTOA. These crosslinking points are mainly formed by the melting and cooling of the PE layer on the ES surface at 140°C. Figure 7 A schematic diagram of the core-shell structure of ES in PTOA is shown. After PE melts and shrinks, the PP core layer is exposed on the surface of ES. Figure 8 , Figure 9 and Figure 10 The diagrams show the distribution of CNPs in the VTLF within the PTOA, the encapsulation of BNNS on the VTLF within the PTOA, and the distribution of BNNS and CNPs within the PTOA: (e.g.) Figure 8 As shown, CNPs are uniformly dispersed between VTLFs without aggregation; Figure 9 and 10 This indicates that BNNS is dispersed in the form of monolayer nanosheets, with all nanosheets tightly connected to form a scale-like layered distribution, similar to the texture of hair. This arrangement can form heat transfer channels, thereby improving the thermal conductivity. The unique spatial arrangement of CNPs and BNNS in the collagen matrix can synergistically enhance the conversion of solar energy to thermal energy and heat transfer. CNPs, due to their strong broadband absorption characteristics, become highly efficient photothermal agents, while the ordered BNNS layers act as in-plane heat transfer channels, jointly improving the heat transfer efficiency at the oil-material interface.

[0040] Compared with two-dimensional field emission scanning electron microscopy (FESEM) images, micro-computed tomography (Micro-241CT) reconstruction can provide a better three-dimensional quantitative assessment of the pore connectivity and anisotropic capillary orientation of the PTOA of the present invention, which is crucial for understanding the macroscopic oil absorption behavior of the PTOA provided by the present invention. Figure 11A schematic diagram of the reconstructed three-dimensional structure of PTOA with a density of 0.027 g / cm³ provided by the present invention is shown. Figure 11 (a) shows, from left to right, a schematic diagram of the micro-CT sample of PTOA provided by the present invention, a schematic diagram of the analysis area and a schematic diagram of the pore size distribution. The PTOA exhibits a loose and highly porous structure. Its internal structure is mainly composed of macropores with a pore size distribution in the range of 100-500µm, accounting for about 98% of the total pore volume. This result is consistent with the above-mentioned FESEM results. Figure 11 (b) shows, from left to right, a schematic diagram of the mixed distribution of fibers, a schematic diagram of the single ES distribution, and a schematic diagram of the single VTLF distribution in the PTOA provided by the present invention. It further shows that the ES and VTLF are uniformly distributed in the PTOA, and the high porosity in the three directions results in permeability coefficients of 2735, 2941 and 2241 Darcy in the X, Y and Z directions, respectively. These values ​​are significantly higher than those of typical porous adsorbents (10-800 Darcy), indicating that the PTOA has a highly interconnected and low-resistance internal network, which is beneficial to fluid transport. Figure 11 Image (c) shows, from left to right, schematic diagrams of the flow field distribution curves of the PTOA in the x, y, and z directions. This flow field simulation further confirms the existence of continuously interconnected oil channels in the PTOA provided by this invention, with minimal stagnation zones and uniform velocity distribution, which is conducive to rapid oil penetration. Overall, the biomimetic structure and hierarchical porosity endow the PTOA provided by this invention with high oil absorption kinetics and excellent stability, providing a structural basis for its superior performance in photothermal crude oil recovery.

[0041] Furthermore, in the process of implementing the embodiments of the present invention, CNPs and BNNS exhibit obvious antagonistic effects, specifically as follows: BNNS tends to reduce the photothermal conversion efficiency of the surface, while CNPs hinder the improvement in thermal conductivity brought about by BNNS.

[0042] The aforementioned mutual interference phenomena cannot be effectively resolved using traditional full-factor experimental design. Therefore, this invention employs Response Surface Methodology (RSM) to optimize the dosage of CNPs and BNNS to comprehensively improve the photothermal and thermal conductivity properties of the product. Specifically, RSM uses the percentage content of CNPs and BNNS as input factors, with the surface temperature T of a 10mm thick photothermal oil-absorbing material as the input factor. top and lower surface temperature T bottom As the response output, a central composite design was adopted, and the levels of each factor were determined based on preliminary single-factor experiments.

[0043] in, Figure 12 , 13 Section 14 illustrates the results of optimizing the CNPs and BNNS usage using the response surface methodology (RSM) in an embodiment of the present invention. Through... Figure 12The schematic diagram showing the single-factor experimental results of the effect of CNPs and BNNS content on the bottom temperature of the PTOA provided by this invention shows that, with the increase of CNPs or BNNS content, the bottom surface temperature T of the photothermal oil-absorbing material increases. bottom All concentrations increased, with a maximum increase of approximately 20%. Beyond this value, further temperature increases were negligible. Therefore, in the RSM experiment, the concentration ranges for CNPs and BNNS were set at 1%–20%. Figure 13 The schematic diagram showing the effect of CNPs and BNNS content on the response surface temperature of the top surface of the oil-absorbing material indicates that T top The photothermal effect is mainly influenced by the content of CNPs, while the influence of BNNS is relatively small. This is because the excellent photothermal properties of CNPs are attributed to their strong broadband absorption and efficient photothermal conversion achieved through non-radiative decay. In contrast, BNNS mainly enhances thermal conductivity due to its high intrinsic thermal conductivity, but its weaker light absorption limits its direct contribution to the photothermal effect. Figure 14 The schematic diagram showing the effect of CNPs and BNNS content on the response surface temperature of the bottom surface of the oil-absorbing material indicates that the content of both CNPs and BNNS affects the temperature of the bottom surface of the oil-absorbing material. bottom It has a significant impact; the increase in CNP content continuously increases T. bottom This is due to the increased photothermal conversion efficiency and the increased surface heat generation; conversely, the BNNS content has an effect on T Bottom The effects exhibit a saddle-shaped trend; both insufficient and excessive BNNS levels can lead to T Bottom The decrease indicates that an appropriate amount of BNNS is beneficial for the effective conduction of heat from the upper surface to the lower surface; however, excessive BNNS may reduce the photothermal performance of the upper surface by shielding or scattering incident light, thereby reducing thermal conductivity and total heat generation.

[0044] After RSM optimization, the effects of CNPs and BNNS usage on T top and T bottom The equation for the effect is as follows: T top =77.8+0.447x−0.117y Formula 1; T bottom =39.51+1.35x+0.5y+0.425xy+0.9638x 2 –1.04y 2 +0.775x 2 Formula 2; Where x represents CNPs%, y represents BNNS%, and T is calculated using formulas 1 and 2. top and T bottomThe optimal values ​​are 85.3°C and 42.3°C, respectively, with CNPs%=20%, BNNS%=17%, and each indicator weight is 0.5, with an expected value of 0.993.

[0045] In a preferred embodiment, the parameters used in the high-pressure pulsed water jet method include: The nozzle diameter of the high-pressure spray gun is 2.5 mm; the pressure of the high-pressure pump is 700 bar, and the flow rate is 4 L / min; the preset angle is 25°.

[0046] In a preferred embodiment, the method for preparing the boron nitride nanosheet dispersion includes: Boron nitride nanosheets were added to deionized water and then ultrasonically dispersed for 30 minutes using an ultrasonic cleaner to ensure uniform dispersion of the boron nitride nanosheets, resulting in a homogeneous and stable boron nitride nanosheet dispersion. In a preferred embodiment, the mass ratio of the two-component ethylene-propylene fiber, the collagen fiber, the carbon nanoparticles, and the boron nitride nanosheets was 0.5:0.5:0.2:0.17, respectively.

[0047] In a preferred embodiment, the mass ratio of polydimethylsiloxane to n-hexane in the polydimethylsiloxane / n-hexane solution is 0.025:1.

[0048] In a preferred embodiment, the pore size of each capillary channel in the hierarchical capillary network of the photothermal oil-absorbing material is 70nm-500µm.

[0049] In a preferred embodiment, the oil absorption rate of the photothermal oil-absorbing material is 168-256 g / (g·min).

[0050] In a preferred embodiment, the density of the photothermal oil-absorbing material is 0.027 g / cm³.

[0051] Further experiments showed that the PTOA provided by this invention has an oil absorption rate of up to 168–256 g / (g·min) and a maximum oil absorption capacity of 27.6 g / g. Under a solar radiation intensity of 1 kW / m², the surface temperature reaches 80.4°C within 2.3 minutes, rapidly reducing the viscosity of the oil and promoting absorption. Moreover, the PTOA retains more than 70% of its capacity after 20 cycles and exhibits excellent environmental stability and flame retardancy.

[0052] Compared with existing technologies, the photothermal oil-absorbing material with a hierarchical capillary network and its preparation method provided by the present invention have the following advantages: This invention provides a photothermal oil-absorbing material with a hierarchical capillary network and its preparation method. The photothermal oil-absorbing material is obtained by in-situ thermal bonding of bicomponent ethylene-propylene fibers and collagen fibers. This allows the collagen fibers, rich in fine capillaries, to entwine around the surface of the more porous bicomponent ethylene-propylene fibers, forming a hierarchical capillary network. This accelerates the adsorption performance of the photothermal oil-absorbing material on oils. Furthermore, by directionally stacking and continuously anchoring boron nitride nanosheets onto the surface of the bicomponent ethylene-propylene fibers to form a large-area continuous thermal conduction pathway, and by adding carbon nanoparticles, the photothermal conversion efficiency and thermal conductivity of the photothermal oil-absorbing material are synergistically enhanced. This allows heat from the upper surface of the photothermal oil-absorbing material to be rapidly transferred to the oil-material interface to reduce oil viscosity, thereby further improving the adsorption performance of the photothermal oil-absorbing material on oils.

[0053] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

[0054] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. It should be understood that the invention is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for preparing a photothermal oil-absorbing material with a hierarchical capillary network, characterized in that, The preparation method of the photothermal oil-absorbing material includes: A high-pressure pulsed water jet method is used to spray a boron nitride nanosheet dispersion onto the surface of a two-component ethylene-propylene fiber at a preset angle, so that the boron nitride nanosheets are continuously anchored to the surface of the two-component ethylene-propylene fiber along the fluid direction. After mixing the bicomponent ethylene-propylene fiber anchored with boron nitride nanosheets with collagen fiber, carbon nanoparticles are added for homogenization to obtain mixed fiber. The mass ratio of the bicomponent ethylene-propylene fiber, the collagen fiber, the carbon nanoparticles and the boron nitride nanosheets are 0.5:0.5:0.01-0.2:0.01-0.2, respectively. The mixed fibers are carded by a carding machine to obtain a mixed fiber web. The mixed fiber web is then evenly cut and fed into a flat mold of a preset size for compaction to obtain a felt-like preform. The felt-like preform is placed in a continuous hot air furnace at 140°C for 5 minutes for heat bonding treatment, then cooled to room temperature and demolded to obtain a semi-finished product of photothermal oil-absorbing material. The semi-finished photothermal oil-absorbing material is immersed in a polydimethylsiloxane / n-hexane solution for 10 minutes, then removed and dried in an oven at room temperature for 30 minutes to obtain a photothermal oil-absorbing material with a hierarchical capillary network. The mass ratio of polydimethylsiloxane to n-hexane in the polydimethylsiloxane / n-hexane solution is 0.015-0.035:

1.

2. The method for preparing the photothermal oil-absorbing material according to claim 1, characterized in that, The parameters used in the high-pressure pulsed water jet method include: The nozzle diameter of the high-pressure spray gun is 2.5 mm; the pressure of the high-pressure pump is 700 bar, and the flow rate is 4 L / min; the preset angle is 25°.

3. The method for preparing the photothermal oil-absorbing material according to claim 1, characterized in that, The preparation method of the boron nitride nanosheet dispersion includes: After adding boron nitride nanosheets to deionized water, ultrasonic dispersion was performed for 30 minutes using an ultrasonic cleaner to ensure uniform dispersion of the boron nitride nanosheets, resulting in a homogeneous and stable boron nitride nanosheet dispersion.

4. The method for preparing the photothermal oil-absorbing material according to claim 1, characterized in that, The mass ratios of the bicomponent ethylene-propylene fiber, the collagen fiber, the carbon nanoparticles, and the boron nitride nanosheets are 0.5:0.5:0.2:0.17, respectively.

5. The method for preparing the photothermal oil-absorbing material according to claim 1, characterized in that, The mass ratio of polydimethylsiloxane to n-hexane in the polydimethylsiloxane / n-hexane solution is 0.025:

1.

6. The method for preparing the photothermal oil-absorbing material according to claim 1, characterized in that, The pore size of each capillary channel in the hierarchical capillary network of the photothermal oil-absorbing material is 70 nm-500 µm.

7. The preparation method according to claim 1, characterized in that, The oil absorption rate of the photothermal oil-absorbing material is 168-256 g / (g·min).

8. The preparation method according to claim 1, characterized in that, The density of the photothermal oil-absorbing material is 0.027 g / cm³.

9. A photothermal oil-absorbing material with a hierarchical capillary network, characterized in that, The photothermal oil-absorbing material is prepared by any one of the preparation methods of the photothermal oil-absorbing material according to claims 1-8, and the oil absorption rate of the photothermal oil-absorbing material is 168-256 g / (g·min).

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