Coal gasification fine slag-based imitation brain fold aerogel porous material and application

Abstract

The application discloses coal gasification fine slag-based brain fold-imitating aerogel porous material and application, and belongs to the field of solid waste resource utilization, and the material has brain cortex fold-imitating structure on the upper surface, and the inside contains 3-4nm, 14-21nm mesoporous and 2-3mu m macroporous interpenetrating pore structure, the macropore porosity reaches 90.45%, and has super-hydrophilic property and wide-spectrum high light absorption capacity;The preparation method comprises the following steps: grinding and screening the coal gasification fine slag, dispersing in chitosan acetic acid solution, adding polyether F127 acetic acid solution and polyvinyl alcohol solution in sequence, crosslinking gelification and aging through glutaraldehyde, adding deionized water on the top of the wet gel for morphology induction, and then directional freezing through liquid nitrogen, water washing to remove the template agent, secondary freeze-drying, and the target material is obtained.The application realizes high-value utilization of coal gasification fine slag, and the material has interface evaporation and soil water-retention improvement functions, and has good application prospect.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization and functional materials, specifically to a brain-like folded aerogel porous material based on coal gasification fine slag and its application. Background Technology

[0002] In the coal chemical industry, the key technology for clean and efficient coal conversion, coal gasification, generates a large amount of solid waste, specifically fine coal gasification slag. This type of solid waste is characterized by high moisture content and complex pore structure, making its resource utilization challenging. Currently, due to immature high-value conversion technologies and limited product application scenarios, the utilization of fine coal gasification slag suffers from low scale, low resource utilization, and low recycling efficiency. Most of it is still disposed of using traditional methods such as stockpiling, landfilling, and mine backfilling. This not only occupies significant land resources but also easily causes ecological disturbances under the influence of rainfall leaching and surface runoff, posing a potential risk to the stability of regional ecosystems.

[0003] Chinese patent (CN118978156A) discloses a method for the comprehensive utilization of multi-component coal gasification waste residue: the waste residue is slurryed and floated to obtain refined carbon and tailings ash; the refined carbon is acid-washed and alkali-activated to prepare CO2-captured porous carbon; the tailings ash is acid-washed with acidic leachate, and the filtrate is adjusted for pH and mineralized with CO2 to prepare calcium-rich filtrate; the silica-alumina residue is alkali-fused and modified to obtain Al2O3-SiO2 aerogel. This process requires multiple flotation, acid washing, and alkali activation, and depends on strong acid and alkali conditions, resulting in a long process, numerous steps, high reagent consumption, and high cost.

[0004] To address the challenges of disposing of fine coal gasification slag and to explore its resource utilization value, this invention uses fine coal gasification slag as a photothermal component to prepare an aerogel porous material. Under illumination, this material can capture light energy and convert it into heat energy, thereby increasing the rate of water evaporation and demonstrating its potential application in the interfacial evaporation treatment of high-salt wastewater. Furthermore, its high porosity, combined with its water absorption and retention properties, can improve the physical and chemical properties of soil, making it a promising candidate for soil water retention and improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a brain-like wrinkled aerogel porous material based on coal gasification fine slag and its applications. A novel method is used to prepare high-value-added aerogels from bulk solid waste coal gasification fine slag as raw material. The technical solution adopted by this invention is as follows: A porous material based on fine coal gasification slag and mimicking brain folds has an upper surface with a folded structure mimicking the cerebral cortex, and an internal pore structure containing interconnected mesopores of 3-4 nm and 14-21 nm and macropores of 2-3 μm. It also has light absorption capacity, water absorption and retention properties, and interfacial evaporation properties. Its surface water contact angle in air is about 0°, exhibiting superhydrophilic characteristics.

[0006] Furthermore, the preparation method of the aerogel porous material is as follows: Step 1: After mechanical grinding, the coal gasification fine slag is screened to obtain 50-200 mesh coal gasification fine slag particles; Step 2: Disperse the coal gasification fine slag particles in chitosan acetic acid solution to obtain coal gasification fine slag dispersion; then add polyether F127 acetic acid solution and polyvinyl alcohol solution, stir, and prepare coal gasification fine slag-based mixed liquid; Step 3: Add glutaraldehyde solution to the coal gasification fine slag-based mixture, stir, and then transfer it to a mold for gel aging to obtain coal gasification fine slag-based wet gel. Step 4: Add deionized water to the top of the coal gasification fine slag-based wet gel for morphology induction, then use liquid nitrogen for directional freezing, and then put the frozen sample into a freeze dryer for drying to obtain the coal gasification fine slag-based solidified material; the principle of morphology induction is that the surface gel absorbs water and swells under the action of osmotic pressure, while the presence of coal gasification fine slag inside leads to the uneven distribution of the micro-gel skeleton and the resulting difference in swelling capacity, so after absorbing water, it forms wrinkles with a cerebral cortex-like structure; Step 5: Wash the coal gasification fine slag-based solidified material with deionized water to remove polyether F127, and then put the material directly into a freeze dryer for freeze drying to obtain the coal gasification fine slag-based brain-like wrinkled aerogel porous material.

[0007] Furthermore, in step 1, the mechanical grinding is carried out using a ball mill with a power of 0.75kW, a rotation speed of 70-670r / min, and a grinding time of 1-2h.

[0008] Further, in step 2, the mass ratio of the coal gasification fine slag particles to the chitosan acetic acid solution is 1:(16-50).

[0009] Further, in step 2, the concentration of chitosan in the chitosan acetate solution is 15-25 g / L; the concentration of polyether F127 in the polyether F127 acetate solution is 25-35 g / L; the solvent of the polyether F127 acetate solution is a 2 wt% glacial acetic acid aqueous solution; and the concentration of polyvinyl alcohol in the polyvinyl alcohol solution is 25-35 g / L.

[0010] Furthermore, in step 3, the glutaraldehyde solution has a mass fraction of 1.5-2.5 wt%, the stirring time is 2-4 min, and the gel aging time is 10-14 h.

[0011] Furthermore, in steps 4 and 5, the morphology induction time is 2-4 minutes; freeze drying is performed using a freeze dryer, and the set parameters of the freeze dryer are: cold trap temperature -86.8℃, vacuum degree 12.4 Pa, drying temperature 25-35℃ (preferably 30℃), and drying time 70-74h (preferably 72h).

[0012] Furthermore, the preparation method of chitosan acetate solution is as follows: Taking the preparation of 20g / L chitosan acetate solution as an example, dissolve 2mL of glacial acetic acid solution in 98mL of deionized water in a beaker, add 2g of chitosan, stir to dissolve, and obtain 20g / L chitosan acetate solution.

[0013] Furthermore, the preparation method of polyether F127 acetic acid solution is as follows: Taking the preparation of 30g / L polyether F127 acetic acid solution as an example, dissolve 2mL of glacial acetic acid solution in 98mL of deionized water in a beaker, add 3g of polyether F127, stir to dissolve, and obtain 30g / L polyether F127 acetic acid solution.

[0014] Furthermore, the preparation method of the polyvinyl alcohol solution is as follows: Taking the preparation of a 30 g / L polyvinyl alcohol solution as an example, dissolve 3 g of polyvinyl alcohol in 100 mL of deionized water in a beaker, and dissolve it by heating and stirring to obtain a 30 g / L polyvinyl alcohol solution; the heating temperature is 180℃ and the rotation speed is 550 r / min.

[0015] Furthermore, the preparation method of glutaraldehyde solution is as follows: Taking the preparation of 2wt% glutaraldehyde solution as an example, measure 8mL of glutaraldehyde solution stock solution (25wt%) and dissolve it in 92mL of deionized water to obtain a glutaraldehyde solution with a mass fraction of 2wt%.

[0016] Furthermore, the prepared material is gray to black in color, with a cylindrical shape, a height of 18-19 mm, and a diameter of 19-21 mm. The upper surface has a cortical-like fold structure, with a depth of approximately 1.51 mm and a width of approximately 1.54 mm. The contact angle between the material surface and water droplets in air is approximately 0°, exhibiting superhydrophilic properties. Under 1 ray of sunlight, the water evaporation efficiency is 2.627-3.122 kg·m³. -2 ·h -1 Among them, the optimal material has a light absorption rate of about 95% in the wavelength range of 200–2500 nm; the internal pore size distribution is mainly composed of mesopores of 3-4 nm and 14-21 nm and macropores of 2-3 μm, which are interconnected, and the macropore porosity is 90.45%; at the same time, its saturated adsorption capacity for pure water reaches 7.18 g / g, and the water loss rate is stable at 8.07% after centrifugation at 1000 r / min for 12 min, showing good water absorption and water retention performance.

[0017] Secondly, based on the superhydrophilic properties, high water retention capacity, and hierarchical porous structure of the material of this invention, the invention also provides the application of a brain-like wrinkled aerogel porous material based on coal gasification fine slag, used as a soil water-retaining agent or soil conditioner. The hierarchical porous structure of the material can effectively store soil moisture, its superhydrophilic surface facilitates rapid water migration between the material and soil particles, while its high water retention capacity allows for the slow release of water to crop roots under drought conditions, extending the effective water supply time of the soil. Simultaneously, the porous structure of the material increases soil porosity; the material can be uniformly mixed with soil particles, and its rigid porous framework is not easily collapsed in the soil, improving soil aggregate structure and enhancing soil aeration and permeability. Therefore, the material of this invention is particularly suitable for water-saving irrigation and soil improvement in agricultural planting in arid and semi-arid regions.

[0018] Thirdly, based on the high light absorption characteristics, superhydrophilicity, and hierarchical porous structure of the material of this invention, the application of a brain-like wrinkled aerogel porous material based on coal gasification fine slag is discussed, using it as an interfacial evaporation material for treating high-salt wastewater. Its working principle is as follows: Due to its high light absorption rate (≥90% in the 200-2500nm wavelength range), the material can efficiently capture sunlight and convert it into heat energy. The heat is localized at the material-water interface, reducing conduction and dissipation into the water body. Simultaneously, its superhydrophilic properties and hierarchical porous structure can continuously transport water from the lower water body to the evaporation surface through capillary action, maintaining a stable water supply and evaporation cycle. Based on the above mechanism, the evaporation efficiency of the material of this invention for high-salt wastewater (3.5wt% NaCl solution) can reach 2.611 kg·m³ under 1 solar radiation intensity. -2 ·h -1 It also has good salt resistance and operational stability, and can provide a low-carbon and environmentally friendly technical approach for the treatment of high-salt wastewater from coal chemical industry and seawater desalination, which does not require external power input and is driven solely by solar energy.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses coal gasification fine slag as the main raw material and, through processes such as pretreatment, compound crosslinking, morphology induction, and directional freeze drying, produces a coal gasification fine slag-based aerogel porous material with an upper surface mimicking the folds of the cerebral cortex. This achieves high-value utilization of coal-based solid waste, effectively reducing material preparation costs and alleviating the environmental pressure caused by the stockpiling of coal gasification fine slag. At the same time, the preparation process is green and environmentally friendly, and the template agent can be removed by water washing and recycled, possessing good potential for large-scale production and engineering applications.

[0020] 2. This invention avoids the harsh conditions such as strong acids, strong alkalis, high temperature and high pressure commonly used in the preparation of traditional aerogels. The entire process can be completed at room temperature and pressure. It is simple to operate, consumes less reagents, is environmentally friendly, and is easy to scale up.

[0021] 3. This invention, through a process combining top deionized water morphology induction and directional freeze-drying, for the first time prepared a porous aerogel material with a cerebral cortex-like folded structure. This folded structure not only significantly increases the effective working area of ​​the material, but also, in conjunction with the multi-level pore network of interconnected 3-4nm and 14-21nm mesopores and 2-3μm macropores, endows the material with excellent capillary water transport and vapor diffusion capabilities.

[0022] 4. The coal gasification fine slag-based brain-like wrinkled aerogel porous material prepared by this invention has a light absorption rate of up to about 95% in a broad spectral range of 200-2500 nm, and its superhydrophilic surface ensures a continuous water supply; under one solar radiation intensity, the pure water evaporation rate can reach 3.122 kg·m³. -2 ·h -1 The evaporation rate for high-salinity wastewater with 3.5 wt% NaCl still reached 2.611 kg·m³. -2 ·h -1 It exhibits efficient and stable interfacial evaporation performance, making it suitable for seawater desalination and high-salinity wastewater treatment without the need for external energy input.

[0023] 5. The coal gasification fine slag-based brain-like folded aerogel porous material prepared by this invention has a saturated adsorption capacity of 7.18 g / g and a water loss rate of only 8.07% after high-speed centrifugation at 1000 r / min for 12 min, indicating that it has extremely strong water retention capacity. Combined with its porous structure, it can improve soil aggregate structure and aeration. The material of this invention can be directly used as a soil water retention agent or soil conditioner, and is suitable for water-saving agriculture in arid and semi-arid regions. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope image of the fine slag from coal gasification used in Example 3 of the present invention.

[0025] Figure 2 The infrared spectrum of the coal gasification slag and chitosan used in Example 3 of this invention.

[0026] Figure 3 The image shows a photograph of 0.2g of the coal gasification fine slag-based aerogel prepared in Example 3 of this invention; where a is a side view of the aerogel and b is a top view of the aerogel.

[0027] Figure 4 The images shown are scanning electron microscope (SEM) images of 0.2 g of coal gasification fine slag-based aerogel prepared in Example 3 of this invention; wherein, a is a cross-sectional SEM image of the sample at a scale of 500 μm, b is a cross-sectional SEM image of the sample at a scale of 200 μm, c is a longitudinal SEM image of the sample at a scale of 500 μm, and d is a longitudinal SEM image of the sample at a scale of 200 μm.

[0028] Figure 5 The UV-Vis-NIR absorption spectrum of 0.2g of the coal gasification fine slag-based aerogel prepared in Example 3 of this invention is shown.

[0029] Figure 6 The differential curve of mesopore size distribution of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3 of the present invention was obtained by measuring with a fully automated N2- physical adsorption-desorption instrument.

[0030] Figure 7 The macropore size distribution curve of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3 of this invention is shown.

[0031] Figure 8 This is a test diagram of the contact angle between the surface of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3 of the present invention and a water droplet.

[0032] Figure 9 This is a schematic diagram of the interface evaporation testing device of the present invention; Figure 10 The figures are mass loss-time curves for each comparative example and embodiment; where a is the mass loss-time curve of deionized water in the control group, b is the mass loss-time curve of 0.1g of coal gasification fine slag-based aerogel prepared in Example 1 on the surface of deionized water, c is the mass loss-time curve of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3 of the present invention on the surface of deionized water, d is the mass loss-time curve of 0.2g (unwrinkled) of coal gasification fine slag-based aerogel prepared in Comparative Example 1 on the surface of deionized water, e is the mass loss-time curve of 0.3g of coal gasification fine slag-based aerogel prepared in Example 2 on the surface of deionized water, and f is the mass loss-time curve of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3 of the present invention on the surface of 3.5wt% NaCl solution.

[0033] Figure 11 The saturated water absorption curve of 0.2g of the coal gasification fine slag-based aerogel prepared in Example 3 of this invention.

[0034] Figure 12 The graph shows the water loss rate of 0.2g of the coal gasification fine slag-based aerogel prepared in Example 3 of this invention after saturation adsorption under centrifugation.

[0035] Figure labeling: 1. Container, 2. Polyethylene foam, 3. Aerogel, 4. Weighing equipment, 5. Xenon lamp. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The following experimental results are all obtained by taking the average value after repeating the test three times.

[0037] The leaching concentration of heavy metal ions in the coal gasification fine slag used was tested according to the standards of "Determination of 32 Elements in Water by Inductively Coupled Plasma Atomic Emission Spectrometry" (HJ 776-2015) and "Determination of Mercury, Arsenic, Selenium, Bismuth and Antimony in Solid Waste by Microwave Digestion / Atomic Fluorescence" (HJ 702-2014). The test results were compared with those of "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3-2007). The leaching concentrations of each heavy metal ion were lower than the standard limits, indicating that the material has good environmental safety.

[0038] The sources and characteristics of the raw materials / reagents used in this invention are shown in Table 1.

[0039] Table 1. Sources and properties of raw materials / reagents used in this invention.

[0040] Example 1 A porous material of brain-like wrinkled aerogel based on coal gasification fine slag, which is prepared by the following method: Step 1: The coal gasification slag is first coarsely crushed using a ball mill, and then finely ground using a mortar and pestle to screen out coal gasification slag particles with a mesh size of 200. In this embodiment, the ball mill has a power of 0.75kW, a rotation speed of 400r / min, and a ball milling time of 1h.

[0041] Step 2: Prepare a 20 g / L chitosan acetic acid solution: Dissolve 2 mL of glacial acetic acid solution in 98 mL of deionized water in a beaker, add 2 g of chitosan, and stir until dissolved to obtain a 20 g / L chitosan acetic acid solution; Weigh 0.1 g of the coal gasification fine slag screened in Step 1 and disperse it in 5.0 g of chitosan acetic acid solution to obtain a coal gasification fine slag dispersion; Prepare a 30 g / L polyether F127 acetic acid solution: Dissolve 2 mL of glacial acetic acid solution in 98 mL of deionized water in a beaker, add 3 g of polyether F127, and stir until dissolved to obtain a 30 g / L polyether F127 acetic acid solution. 0 g / L polyether F127 acetic acid solution; Preparation of 30 g / L polyvinyl alcohol solution: Dissolve 3 g of polyvinyl alcohol in 100 mL of deionized water, and stir with a heated magnetic stirrer at 550 r / min and 180 °C to obtain a 30 g / L polyvinyl alcohol solution; Add 1.5 mL of the prepared polyether F127 acetic acid solution (the amount of deionized water added should be enough to completely wet the top surface of the gel) and 0.4 mL of polyvinyl alcohol solution to the coal gasification fine slag dispersion, and stir thoroughly to obtain a coal gasification fine slag-based mixture.

[0042] Step 3: Prepare a 2wt% glutaraldehyde solution: Dissolve 8mL of glutaraldehyde stock solution (25wt%) in 92mL of deionized water to obtain a 2wt% glutaraldehyde solution; add 1.2mL of the prepared glutaraldehyde solution to the coal gasification fine slag-based mixture prepared in Step 2, stir for 2min, transfer to a mold and gel for 10h to obtain a coal gasification fine slag-based wet gel.

[0043] Step 4: Add 1.5 mL of deionized water to the top of the above wet gel, let it stand for 2 min, then use liquid nitrogen for directional freezing, and then put the frozen sample into a freeze dryer for drying to obtain coal gasification fine slag-based solidified material; the freeze dryer cold trap temperature is -86.8℃, the vacuum degree is 12.4 Pa, the drying temperature is 30℃, and the drying time is 72 h.

[0044] Step 5: The above-mentioned coal gasification fine slag-based solidified material was washed with deionized water to remove the polyether F127 mesoporous template. The material was then directly placed in a freeze dryer for freeze drying to obtain a coal gasification fine slag-based aerogel porous material. The freeze dryer's cold trap temperature was -86.8℃, vacuum degree was 12.4 Pa, drying temperature was 30℃, and drying time was 72 h. The final product was a coal gasification fine slag-based brain-like wrinkled aerogel porous material, denoted as coal gasification fine slag-based aerogel-0.1 g.

[0045] Example 2 A porous material of brain-like wrinkled aerogel based on coal gasification fine slag, which is prepared by the following method: Step 1: The coal gasification slag is first coarsely crushed using a ball mill, and then finely ground using a mortar and pestle to screen out coal gasification slag particles with a mesh size of 200. In this embodiment, the ball mill has a power of 0.75kW, a rotation speed of 400r / min, and a ball milling time of 1h.

[0046] Step 2: Prepare a 20 g / L chitosan acetic acid solution: Dissolve 2 mL of glacial acetic acid solution in 98 mL of deionized water in a beaker, add 2 g of chitosan, and stir until dissolved to obtain a 20 g / L chitosan acetic acid solution; Weigh 0.3 g of the coal gasification fine slag screened in Step 1 and disperse it in 5.0 g of chitosan acetic acid solution to obtain a coal gasification fine slag dispersion; Prepare a 30 g / L polyether F127 acetic acid solution: Dissolve 2 mL of glacial acetic acid solution in 98 mL of deionized water in a beaker, and add 3 g of polyether... F127 was dissolved by stirring to obtain a 30 g / L polyether F127 acetic acid solution; a 30 g / L polyvinyl alcohol solution was prepared by dissolving 3 g of polyvinyl alcohol in 100 mL of deionized water and stirring at 550 r / min and 180 °C using a heated stirring table to obtain a 30 g / L polyvinyl alcohol solution; 1.5 mL of the prepared polyether F127 acetic acid solution and 0.4 mL of polyvinyl alcohol solution were added to the coal gasification fine slag dispersion and stirred thoroughly to obtain a coal gasification fine slag-based mixed solution.

[0047] Step 3: Prepare a 2wt% glutaraldehyde solution: Dissolve 8mL of glutaraldehyde stock solution (25wt%) in 92mL of deionized water to obtain a 2wt% glutaraldehyde solution; add 1.2mL of the prepared glutaraldehyde solution to the coal gasification fine slag-based mixture prepared in Step 2, stir for 4min, transfer to a mold and gel for 14h to obtain a coal gasification fine slag-based wet gel.

[0048] Step 4: Add 1.5 mL of deionized water to the top of the above wet gel, let it stand for 4 min to induce morphology, then use liquid nitrogen for directional freezing, and then put the frozen sample into a freeze dryer for drying to obtain coal gasification fine slag-based solidified material; the freeze dryer cold trap temperature is -86.8℃, the vacuum degree is 12.4 Pa, the drying temperature is 30℃, and the drying time is 72 h.

[0049] Step 5: The above-mentioned coal gasification fine slag-based solidified material was washed with deionized water to remove the polyether F127 mesoporous template. Then, it was freeze-dried to obtain a coal gasification fine slag-based aerogel porous material. The freeze dryer cold trap temperature was -86.8℃, the vacuum degree was 12.4 Pa, the drying temperature was 30℃, and the drying time was 72 h. The final product was a coal gasification fine slag-based brain-like wrinkled aerogel porous material, denoted as coal gasification fine slag-based aerogel-0.3 g.

[0050] Example 3 A porous material of brain-like wrinkled aerogel based on coal gasification fine slag, which is prepared by the following method: Step 1: The coal gasification slag is first coarsely crushed using a ball mill, and then finely ground using a mortar and pestle to screen out coal gasification slag particles with a mesh size of 200. In this embodiment, the ball mill has a power of 0.75kW, a rotation speed of 400r / min, and a ball milling time of 1h.

[0051] Step 2: Prepare a 20 g / L chitosan acetic acid solution: Dissolve 2 mL of glacial acetic acid solution in 98 mL of deionized water in a beaker, add 2 g of chitosan, and stir until dissolved to obtain a 20 g / L chitosan acetic acid solution; Weigh 0.2 g of the coal gasification fine slag screened in Step 1 and disperse it in 5.0 g of chitosan acetic acid solution to obtain a coal gasification fine slag dispersion; Prepare a 30 g / L polyether F127 acetic acid solution: Dissolve 2 mL of glacial acetic acid solution in 98 mL of deionized water in a beaker, and add 3 g of polyether... F127 was dissolved by stirring to obtain a 30 g / L polyether F127 acetic acid solution; a 30 g / L polyvinyl alcohol solution was prepared by dissolving 3 g of polyvinyl alcohol in 100 mL of deionized water and stirring at 550 r / min and 180 °C using a heated stirring table to obtain a 30 g / L polyvinyl alcohol solution; 1.5 mL of the prepared polyether F127 acetic acid solution and 0.4 mL of polyvinyl alcohol solution were added to the coal gasification fine slag dispersion and stirred thoroughly to obtain a coal gasification fine slag-based mixed solution.

[0052] Step 3: Prepare a 2wt% glutaraldehyde solution: Dissolve 8mL of glutaraldehyde stock solution (25wt%) in 92mL of deionized water to obtain a 2wt% glutaraldehyde solution; add 1.2mL of the prepared glutaraldehyde solution to the coal gasification fine slag-based mixture prepared in Step 2, stir for 3min, transfer to a mold and gel for 12h to obtain a coal gasification fine slag-based wet gel.

[0053] Step 4: Add 1.5 mL of deionized water to the top of the above wet gel, let it stand for 3 min, then use liquid nitrogen for directional freezing, and then put the frozen sample into a freeze dryer for drying to obtain coal gasification fine slag-based solidified material; the freeze dryer cold trap temperature is -86.8℃, the vacuum degree is 12.4 Pa, the drying temperature is 30℃, and the drying time is 72 h.

[0054] Step 5: Use deionized water to wash the above coal gasification fine slag-based solidified material to remove the polyether F127 mesoporous template, and then freeze-dry it to finally obtain the coal gasification fine slag-based aerogel porous material, denoted as coal gasification fine slag-based aerogel-0.2g; the cold trap temperature of the freeze dryer is -86.8℃, the vacuum degree is 12.4Pa, the drying temperature is 30℃, and the drying time is 72h.

[0055] Figure 1 The image shows a scanning electron microscope (SEM) image of the coal gasification fine slag used in Example 3 of this invention. As can be seen from the image, at a scale of 20 μm, the coal gasification fine slag is composed of multi-scale particles. The main particles are irregularly shaped blocks with rough surfaces and a large number of pores of uneven size. The morphology of the surrounding debris particles is consistent with that of the main particles.

[0056] Figure 2 The image shows the infrared spectra of the coal gasification fine slag and chitosan used in Example 3 of this invention. As can be seen from the image, the coal gasification fine slag... -1 The presence of a characteristic -OH absorption peak at [location missing] indicates that the hydroxyl group, acting as a hydrophilic group, imparts excellent hydrophilic properties to the raw material; while chitosan exhibits a peak at 1589.9 cm⁻¹. -1 The -NH2 characteristic absorption peak is present at the point, indicating that this active amino group can readily undergo a cross-linking reaction with the cross-linking agent glutaraldehyde solution.

[0057] Figure 3 Figure 3a shows the morphological observation of the coal gasification fine slag-based aerogel prepared in Example 3 of this invention. As can be seen from the figure, the coal gasification fine slag-based aerogel (0.2g) is black and cylindrical. Measurements show its diameter d = 21.40 mm and height h = 17.80 mm. Its macroscopic volume V can be calculated using the formula for cylinder volume. b =6.399cm 3 The mass m of the aerogel was weighed using an electronic analytical balance. b =0.3727g.

[0058] Figure 3 Figure b shows a macroscopic top view of 0.2g of coal gasification fine slag-based aerogel. Its top features a continuous, dense, and uniformly distributed cortical-like folded morphology. The depth of the folded structure is 1.51 mm and the width is approximately 1.54 mm. The unique cortical-like folded structure not only gives the material a larger effective working area, but also provides a structural basis for its efficient photothermal conversion and continuous moisture transport in applications such as interfacial evaporation.

[0059] Figure 4 This is a scanning electron microscope (SEM) image of 0.2 g of the coal gasification fine slag-based aerogel prepared in Example 3 of this invention. Figure 4 As shown in Figure a, at a scale of 500 μm, the cross-section of the coal gasification fine slag-based aerogel-0.2 g exhibits a uniform honeycomb porous structure. Figure 4 As shown in b, under a 200μm scale, the pores in its cross-section are interconnected, with thin and interconnected pore walls, forming a continuous three-dimensional network structure. Figure 4As shown in c, at a scale of 500 μm, it can be observed that the pores of the longitudinal section of the coal gasification fine slag-based aerogel (0.2 g) are oriented vertically; as shown in c. Figure 4 As shown in d, the complete structure and morphology of the longitudinal section directional channel can be clearly observed under a 200μm scale.

[0060] Figure 5 The image shows the UV-Vis-NIR absorption spectrum of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3 of this invention. Detection using a UV-Vis-NIR spectrometer revealed that the absorbance of 0.2g of the coal gasification fine slag-based aerogel was approximately 95% in the wavelength range of 200-2500 nm, demonstrating excellent light absorption capabilities.

[0061] Figure 6 The differential curve of mesopore size distribution of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3 of this invention was measured using a fully automated N2-physical adsorption-desorption instrument. As can be seen from the figure, the mesopores of 0.2g of coal gasification fine slag-based aerogel are mainly concentrated in the ranges of 3-4 nm and 14-21 nm.

[0062] Figure 7 The graph shows the macropore size distribution of 0.2g of the coal gasification fine slag-based aerogel prepared in Example 3 of this invention, measured using a fully automated mercury porosimeter. As can be seen from the graph, the macropores of the 0.2g coal gasification fine slag-based aerogel are mainly concentrated in the 2-3 μm range; simultaneously, the mercury porosimeter test results show that the macropore porosity of the coal gasification fine slag-based aerogel is 90.45%. Combined with the aforementioned mesoporous structure, this demonstrates that the coal gasification fine slag-based aerogel prepared in Example 3 of this invention possesses both mesoporous and macroporous pore structures internally.

[0063] Figure 8 This image shows the contact angle test results of 0.2g of the coal gasification fine slag-based aerogel prepared in Example 3 of this invention with a water droplet in air. Detected using a video optical contact angle meter, the water droplet rapidly spreads and penetrates the material surface, with the water contact angle on the sample surface approaching 0°, exhibiting superhydrophilicity.

[0064] The evaporation efficiency of 0.2 g of the coal gasification fine slag-based aerogel prepared in Example 3 was tested. The test procedure is as follows: Figure 9The diagram shows a schematic of an interfacial evaporation testing device according to the present invention. The device includes a container 1 filled with deionized water; a polyethylene foam 2 is used as a support, with a central hole in the polyethylene foam 2 into which the aerogel 3 prepared according to the present invention is embedded. The polyethylene foam 2 is placed on the surface of the deionized water and floats, with the lower surface of the aerogel 3 in contact with the deionized water (the lower surface is immersed in the deionized water for approximately 1 mm). The container 1 is placed on a weighing device 4, such as an electronic scale, to measure the mass change of the container 1. The entire device is installed directly below the xenon lamp 5 of a xenon lamp light source system. The xenon lamp 5 light source system is model CEL-HXF300-T3. The xenon lamp light source system simulates sunlight.

[0065] During the test, under simulated sunlight (1sun irradiation), the mass of container 1 continuously decreased. The change in the mass of container 1 over time was recorded, such as... Figure 10 Figure c shows the mass loss-time curve obtained from the evaporation efficiency test of 0.2g of the coal gasification fine slag-based aerogel of this invention. Linear fitting revealed that the evaporation rate of 0.2g of the coal gasification fine slag-based aerogel was 3.122 kg·m⁻¹. -2 ·h -1 .

[0066] control group Adopting such Figure 9 The interface evaporation test apparatus shown was used to test evaporation performance. The apparatus includes a container 1, polyethylene foam 2, a weighing device 4, and a xenon lamp 5. Deionized water was added to container 1, and polyethylene foam 2 was placed on the surface of the deionized water, floating (without any aerogel material), with a central opening exposed above the water surface. Container 1 was placed directly under the xenon lamp 5 of the xenon lamp light source system (model CEL-HXF300-T3), and the evaporation test was conducted under simulated sunlight (1 sun). The change in the mass of container 1 over time was recorded. Figure 10 As shown in figure a, the evaporation rate of pure water, obtained through linear fitting, is 0.622 kg·m³. -2 ·h -1 .

[0067] Comparative Example 1 In this comparative example, the method for preparing coal gasification fine slag-based aerogel is as follows: the operation of "adding 1.5 mL of deionized water to the top of the wet gel and letting it stand for 3 min to induce morphology" in step 4 of Example 3 is omitted. That is, the wet gel is directly subjected to liquid nitrogen directional freezing. The remaining operation steps are the same as in Example 3. The prepared coal gasification fine slag-based aerogel is recorded as coal gasification fine slag-based aerogel-0.2 g (without wrinkles).

[0068] Using the same interfacial evaporation testing apparatus and conditions as the control group, the evaporation rate was tested under simulated sunlight, and the change in the mass of container 1 over time was recorded. Figure 10 As shown in d, the evaporation rate of 0.2 g (unwrinkled) of coal gasification fine slag-based aerogel was found to be 2.773 kg·m⁻¹ after linear fitting. -2 ·h -1 .

[0069] Comparative analysis of the interfacial evaporation test results of Examples 1, 3, and 2 and Comparative Example 1 ( Figure 10 b- Figure 10 e) It can be seen that the amount of fine coal gasification slag added has a significant impact on the evaporation rate. When the amount added increases from 0.1g (Example 1) to 0.2g (Example 3), the evaporation rate increases from 2.627kg·m³. -2 ·h -1 Increased to 3.122 kg·m -2 ·h -1 This is because the increased content of fine coal gasification slag, as the main light-absorbing component, provides more light-harvesting sites, enhancing the photothermal conversion capacity of the material and thus effectively driving moisture evaporation. However, when the addition amount was further increased to 0.3 g (Example 2), the evaporation rate actually decreased to 3.028 kg·m³. -2 ·h -1 This is lower than the 3.122 kg·m³ of Example 3. -2 ·h -1 The reason is that excessive fine slag particles tend to aggregate within the aerogel framework, leading to partial pore blockage, reducing the material's porosity and capillary water transport capacity, and consequently restricting the continuous supply of water from the bottom to the evaporation surface. The above results indicate that there is an optimal range for the amount of fine slag added in coal gasification, and the 0.2g addition amount of this invention is the preferred ratio.

[0070] Furthermore, comparing the evaporation rates of Example 3 (with folds) and Comparative Example 1 (without folds), it can be seen that the introduction of the cerebral cortex-inspired fold structure reduces the evaporation rate from 2.773 kg·m³. -2 ·h -1 Increased to 3.122 kg·m -2 ·h -1 Although the wrinkled structure has a limited direct contribution to light absorption, it macroscopically increases the contact area between the material and air, while providing more channels for water vapor to escape, which is beneficial for the rapid diffusion and evaporation of moisture at the interface. Therefore, the brain-inspired wrinkled structure and the hierarchical channels work synergistically to ensure the material's efficient interfacial evaporation performance.

[0071] The comparison results between Comparative Example 1 and Examples 1-3 show that the amount of coal gasification fine slag added directly affects the photothermal evaporation efficiency. The evaporation rate is optimal when the amount of coal gasification fine slag added is 0.2 g. The cortical-like folded structure induced by the top deionized water morphology can further improve the water conveyance efficiency. The heavy metal leaching concentration of the prepared material meets the national standard limits, exhibiting good environmental safety. It can be used simultaneously for interfacial evaporation treatment of high-salt wastewater and soil water retention and improvement, realizing the high-value and resource utilization of coal-based solid waste, and possessing significant economic and environmental benefits.

[0072] Experiment 1 Using the same interfacial evaporation testing apparatus and conditions as the control group, the evaporation rate of 0.1 g of the coal gasification fine slag-based aerogel prepared in Example 1 was tested under simulated sunlight, and the change in the mass of container 1 over time was recorded. Figure 10 As shown in b, the evaporation rate of 0.1 g of coal gasification fine slag-based aerogel was found to be 2.627 kg·m⁻¹ after linear fitting. -2 ·h -1 .

[0073] Using the same interfacial evaporation testing apparatus and conditions as the control group, the evaporation rate of 0.3 g of the coal gasification fine slag-based aerogel prepared in Example 2 was tested under simulated sunlight, and the change in the mass of container 1 over time was recorded. Figure 10 As shown in e, the evaporation rate of 0.3 g of coal gasification fine slag-based aerogel was found to be 3.028 kg·m⁻¹ after linear fitting. -2 ·h -1 .

[0074] Experiment 2 To evaluate the interfacial evaporation performance of coal gasification fine slag-based aerogel in a high-salt environment, this experiment used a 3.5 wt% NaCl solution to simulate high-salt wastewater and tested the evaporation rate of a 0.2 g sample of coal gasification fine slag-based aerogel prepared in Example 3.

[0075] In this experiment, only the solution added to container 1 of the test device was adjusted to be a 3.5wt% NaCl solution, and the other devices were the same as the control group. To prepare the 3.5wt% NaCl solution, take 3.50g of NaCl solid, add it to 96.50g of deionized water, stir until completely dissolved, and a 3.5wt% NaCl solution is prepared.

[0076] Evaporation rate tests were conducted under simulated sunlight (1sun), and the change in the mass of container 1 over time was recorded. Figure 10 Figure f shows the mass loss-time curve of 0.2g of coal gasification fine slag-based aerogel. Linear fitting revealed that the evaporation rate of 0.2g of coal gasification fine slag-based aerogel was 2.611 kg·m⁻¹. -2 ·h-1 .

[0077] Experiment 3 To evaluate the water absorption performance of coal gasification fine slag-based aerogel, this invention conducted a saturation water absorption test on 0.2g of the coal gasification fine slag-based aerogel prepared in Example 3. The test procedure is as follows: The sample was completely immersed in deionized water. Every 1 minute, the sample was removed from the deionized water, and the surface moisture was absorbed with filter paper. The weight was recorded until the difference between two consecutive weighings was less than 0.001g. At this point, the sample was considered to have reached water saturation. Timing was stopped and the corresponding time was recorded. This time is the saturation adsorption time of the material. Figure 11 The figure shows the water absorption saturation curve of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3. The test results show that the saturation adsorption time of this sample in deionized water is 10min and the saturation adsorption amount is 7.18g / g, which demonstrates good water absorption performance.

[0078] Experiment 4 This invention tests the water retention capacity of 0.2 g of coal gasification fine slag-based aerogel prepared in Example 3. The test procedure is as follows: The coal gasification fine slag-based aerogel after the water absorption test is centrifuged in a high-speed centrifuge at 1000 r / min, and the weight of the sample is measured every 3 min of centrifugation; Figure 12 The figure shows the water loss rate curve of 0.2g of coal gasification fine slag-based aerogel prepared in Example 3 of this invention after saturation adsorption under centrifugation. The test results show that the water loss rate of the sample is stable at 8.07% after centrifugation for 12 minutes, indicating good water retention performance.

[0079] In summary, this invention successfully prepared a porous material of coal gasification fine slag-based aerogel with a cortical-like folded morphology on its upper surface and a hierarchical pore structure using coal gasification fine slag and chitosan as main raw materials through pretreatment, composite cross-linking, morphology induction, directional freeze-drying, template removal, and freeze-drying processes. The coal gasification fine slag-based aerogel prepared in Example 3 (0.2g) exhibited a light absorption rate of approximately 95% in the 200–2500 nm wavelength range; the contact angle between the material surface and water droplets in air was approximately 0°, demonstrating superhydrophilic properties; the material contained a hierarchical pore structure, and characterization by mercury intrusion porosimetry and nitrogen adsorption showed that its pore size distribution was mainly composed of mesopores of 3-4 nm and 14-21 nm and macropores of 2-3 μm, with a macropore porosity of 90.45%; the water evaporation efficiency reached 3.122 kg·m³ under 1 day of sunlight irradiation. -2 ·h -1 Furthermore, a concentration of 2.611 kg·m³ can be achieved in 3.5 wt% NaCl saline solution. -2 ·h -1The material exhibits high evaporation efficiency; its saturated adsorption capacity reaches 7.18 g / g, and its water loss rate remains stable at 8.07% after centrifugation at 1000 r / min for 12 min, demonstrating excellent water absorption and retention properties.

Claims

1. A coal gasification fine slag-based, brain-crease-imitating aerogel porous material, characterized by, The upper surface of the porous material has a folded structure that mimics the cerebral cortex, and the interior contains a channel structure in which mesopores of 3-4 nm and 14-21 nm and macropores of 2-3 μm are interconnected. It also has light absorption capacity, water absorption and retention capacity and interfacial evaporation capacity. The method for preparing the porous material includes the following steps: Step 1: After mechanically grinding the coal gasification fine slag, screen it to obtain 50-200 mesh coal gasification fine slag particles; Step 2: Disperse the coal gasification fine slag particles in chitosan acetic acid solution to obtain coal gasification fine slag dispersion; then add polyether F127 acetic acid solution and polyvinyl alcohol solution, stir, and prepare coal gasification fine slag-based mixed liquid; Step 3: Add glutaraldehyde solution to the coal gasification fine slag-based mixture, stir, and then transfer it to a mold for gel aging to obtain coal gasification fine slag-based wet gel. Step 4: Add deionized water to the top of the coal gasification fine slag-based wet gel for morphology induction, then use liquid nitrogen for directional freezing, and then put the frozen sample into a freeze dryer for drying to obtain the coal gasification fine slag-based solidified material. Step 5: Wash the coal gasification fine slag-based solidified material with deionized water to remove polyether F127, and then put the material directly into a freeze dryer for freeze drying to obtain the coal gasification fine slag-based brain-like wrinkled aerogel porous material.

2. The coal gasification fine slag-based, brain-crease mimicking aerogel porous material according to claim 1, characterized in that, In step 1, the mechanical grinding is carried out using a ball mill with a power of 0.75kW, a rotation speed of 70-670r / min, and a grinding time of 1-2h.

3. The coal gasification fine slag-based, brain-crease mimicking aerogel porous material according to claim 1, characterized in that, In step 2, the mass ratio of the coal gasification fine slag particles to the chitosan acetic acid solution is 1:(16-50).

4. The coal gasification fine slag-based brain-like wrinkled aerogel porous material according to claim 1, characterized in that, In step 2, the concentration of chitosan in the chitosan acetate solution is 15-25 g / L; the concentration of polyether F127 in the polyether F127 acetate solution is 25-35 g / L; the solvent of the polyether F127 acetate solution is a 2 wt% glacial acetic acid aqueous solution; and the concentration of polyvinyl alcohol in the polyvinyl alcohol solution is 25-35 g / L.

5. The coal gasification fine slag-based brain-like wrinkled aerogel porous material according to claim 1, characterized in that, In step 3, the glutaraldehyde solution has a mass fraction of 1.5-2.5 wt%, the stirring time is 2-4 min, and the gel aging time is 10-14 h.

6. The coal gasification fine slag-based brain-like wrinkled aerogel porous material according to claim 1, characterized in that, In step 4, the morphology induction time is 2-4 min; in steps 4 and 5, the set parameters of the freeze dryer are: cold trap temperature is -86.8℃, vacuum degree is 12.4 Pa, drying temperature is 30℃, and drying time is 70-74 h.

7. The coal gasification fine slag-based brain-like wrinkled aerogel porous material according to any one of claims 1-6, characterized in that, The light absorption capability is: light absorption rate ≥90% in the wavelength range of 200-2500nm; The water absorption and retention performance is as follows: the saturated adsorption capacity for pure water reaches 7.18 g / g, and the water loss rate after centrifugation at 1000 r / min for 12 min is 8.07%. The interface evaporation performance is that the pure water evaporation rate is 3.122 kg·m -2 ·h -1 , under 1 solar intensity, the evaporation rate of 3.5wt% NaCl high-salt wastewater is 2.611 kg·m -2 ·h -1 .

8. The application of a brain-like wrinkled aerogel porous material based on coal gasification fine slag according to any one of claims 1-6, characterized in that, Used as a soil water-retaining agent or soil conditioner.

9. The application of a brain-like wrinkled aerogel porous material based on coal gasification fine slag according to any one of claims 1-6, characterized in that, Used in interfacial evaporation materials for treating high-salt wastewater.

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