Geopolymer foam adsorbent material with vein-like multi-stage network pore structure and preparation method thereof

Abstract

The application belongs to the technical field of new materials, and relates to a geopolymer foam material with a vein-shaped multistage network pore structure and a preparation method thereof. The application comprises the following steps: pretreating luffa, cow horn fiber and coconut fiber respectively, and loading catalysts; uniformly mixing fly ash floating beads, metakaolin, slag, an anionic surfactant, the cow horn fiber loaded with catalysts and the coconut fiber loaded with catalysts to obtain mixed powder; mixing the mixed powder with an alkali activator to prepare a slurry, adding a chemical foaming agent into the slurry, and then pouring the slurry into the luffa loaded with catalysts, and then sequentially performing foaming and curing treatment; and performing freeze-drying and calcination on the cured material, and the geopolymer foam material is obtained; the geopolymer foam material prepared by the application has a vein-shaped multistage pore structure, can have physical and chemical adsorption properties on heavy metal ions and cationic dyes, and can remove pollutants such as macromolecules, microorganisms, perfluoroalkyl compounds and ammonia nitrogen compounds.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology and relates to geopolymer foam adsorbent materials with a vein-like multi-level network pore structure and their preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Geopolymers are a new type of inorganic polymer material. After molding, they possess a dense network molecular structure and exhibit strong adsorption capacity for heavy metal ions and cationic dyes. Compared to traditional adsorption materials, they offer advantages such as simple preparation processes, low carbon emissions, and low cost. Pore structure is crucial for pollution reduction materials, especially in dynamic adsorption treatment, a commonly used industrial process. Therefore, materials require extremely high connectivity and porosity to ensure effective gas and water permeation. However, current geopolymer foam materials have relatively simple pore structures; simple macroporous pores cannot provide the broad adsorption capacity of porous ceramics or activated carbon. Therefore, preparing multi-level pore structures ranging from nanometers to millimeters, while simultaneously endowing these pore structures with the functionality to remove specific pollutants, can enable geopolymers to possess broader physical adsorption, chemical adsorption, and catalytic reaction capabilities, allowing them to simultaneously adsorb pollutants such as heavy metals, organic dyes, macromolecular organic matter, microorganisms, perfluoroalkyl compounds, and ammonia nitrogen compounds. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a geopolymer foam material with a vein-like hierarchical network pore structure and its preparation method. The geopolymer foam material prepared by the present invention has a hierarchical pore structure at the nanoscale, microscale, and millimeter scale, and various functional catalytic materials are anchored in the network pores. It can not only chemically adsorb heavy metal ions and cationic dyes, but also separate macromolecules, microorganisms, perfluoroalkyl compounds, and ammonia nitrogen compounds.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] On the one hand, a method for preparing a geopolymer foam material with a vein-like multi-level network pore structure includes the following steps:

[0007] Alkali metal hydroxides were used to pretreat loofah sponge, horned melon fiber and coconut shell fiber respectively. The pretreated loofah sponge, pretreated horned melon fiber and pretreated coconut shell fiber were loaded with molybdenum catalyst and / or manganese catalyst respectively to obtain catalyst-anchored loofah sponge, catalyst-loaded horned melon fiber and catalyst-loaded coconut shell fiber respectively.

[0008] The fly ash cenospheres, metakaolin, slag, anionic surfactant, hornwort fiber supported on catalyst, and coconut shell fiber supported on catalyst are mixed evenly to obtain a mixed powder.

[0009] Mix the powder with an alkali activator to form a slurry. Add a chemical foaming agent to the slurry and mix evenly. Then inject the mixture into the loaded loofah sponge. Then, perform foaming treatment and curing treatment in sequence. Freeze-dry the cured material and calcine it at 500-800℃ under an inert atmosphere to obtain the final product.

[0010] The composition, by weight, includes 40-60 parts fly ash cenospheres, 20-30 parts metakaolin, 20-30 parts slag, 40-70 parts alkali activator, 5-10 parts total of loofah sponge anchoring catalyst, horn gourd fiber loaded with catalyst, and coconut shell fiber loaded with catalyst, 5-10 parts chemical foaming agent, and 0.4-0.8 parts anionic surfactant.

[0011] This invention, under the condition of anionic surfactant incorporation, allows low-concentration chemical foaming agents to form independently and uniformly distributed micropores within the material. The dense distribution of these micropores, compared to macropores, allows water to flow along them, enabling sufficient contact with the matrix and facilitating efficient physical and chemical adsorption. As the geopolymer reaction proceeds, water is gradually released, leaving a significant amount of residual water in the formed geopolymer matrix. This residual water provides the conditions for preparing interconnected mesopores. Upon transfer to a freeze dryer, the water within the pores rapidly freezes and expands in volume, leaving voids after drying. Since water only migrates along the capillaries within the material, all pathways are interconnected pores. Therefore, the freeze-drying process further expands the water channels (mesopores), enhancing the matrix's connectivity and increasing the contact area between the matrix and water. Macromolecular or bacterial contaminants will remain within the pores.

[0012] Fly ash cenospheres, as hollow spherical active precursors, have been widely used in lightweight fillers. In this invention, fly ash cenospheres corrode under alkali activation, exposing internal voids and creating conditions for matrix connectivity.

[0013] Using catalyst-anchored loofah sponges, catalyst-loaded horned melon fibers, and catalyst-loaded coconut shell fibers as functionalized mesh fiber pore-forming agents, these fibers are formed by crisscrossing fiber bundles with good inter-bundle connectivity and extremely high toughness. The loofah sponges can reach a diameter of 1 mm, thus forming a complex network structure within the matrix. Sodium hydroxide treatment removes organic matter from the cell walls of the loofah sponges, horned melon fibers, and coconut shell fibers, while simultaneously disrupting hydrogen bonds in the fiber structure, increasing surface roughness, making the plant fiber skeleton clearer, and facilitating catalyst anchoring on the surface. This invention anchors compounds such as molybdenum and manganese within the mesh fibers, enabling the geopolymer material to degrade perfluoroalkyl compounds and ammonia nitrogen compounds.

[0014] Functionalized mesh fiber pore-forming agent is a plant fiber that can be calcined and carbonized at high temperatures of 500-800℃. Geopolymer materials have excellent high-temperature resistance and can withstand temperatures up to 1000℃. Therefore, it can ensure that the matrix properties are not damaged when the loofah is fully calcined. After calcination, interconnected pores are formed inside the material.

[0015] The pore structures of various sizes and characteristics prepared by the method of this invention work together to form a pore network inside the material. The numerous interconnected pores generated by calcined functionalized mesh fibers ensure smooth water flow and enable the matrix to perform basic ion exchange functions for pollutants. The matrix is ​​composed of small pores of 0.1 to 1.5 mm made by a pore-forming agent. The pores divide the cross-sectional water flow into countless individual small water flows, allowing the water flow to have a large contact area with the matrix. When the water flow comes into contact with the various small pores formed by freeze-drying on the matrix, it can effectively block pollutants in the water and produce physical adsorption.

[0016] On the other hand, a geopolymer foam material with a vein-like multi-level network pore structure is obtained by the above preparation method.

[0017] Thirdly, the application of the above-mentioned geopolymer foam material with a vein-like multi-level network pore structure in sewage treatment, flue gas purification, or sponge city construction.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) This invention prepares a geopolymer foam material with a vein-like multi-level network pore structure. It makes full use of the high adsorption capacity of geopolymer materials and further imparts a multi-level pore structure to the material through a multi-process organic coordination of multiple plant fiber composites, foaming, freeze drying, calcination and other methods, so that it has the characteristics of chemical and physical adsorption and catalytic reaction, which broadens the application scope of geopolymer materials and deeply explores the application potential of geopolymer adsorption materials.

[0020] (2) The geopolymer foam material with vein-like multi-level network pore structure provided by the present invention contains a novel pore structure. The functionalized mesh fiber pore-forming agent acts as a bridge connecting the pores, increasing the connectivity of the structure, avoiding the use of excessive foaming agent, ensuring the strength of the material, and not weakening the strength due to excessive foaming agent, which is conducive to the integrity of the structure.

[0021] (3) The nano-micro level multi-level pores inside the material provided by the present invention endow the material with filtration and physical adsorption functions.

[0022] (4) The present invention uses loofah sponge anchored with catalyst, horned melon fiber loaded with catalyst, and coconut shell fiber loaded with catalyst as functionalized mesh fiber pore-forming agents, which can serve as catalyst carriers, thus broadening the application of geopolymers in pollution control. Combined with foaming, mesoporous bubbles can be formed by adhering to the mesh fiber growth. After the material solidifies, it becomes interconnected, enhancing the adsorption effect. The functionalized mesh fiber pore-forming agent, after high-temperature sintering, becomes fibrous biochar, which also has adsorption function, increasing the degradation efficiency of pollutants. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] Given the limited adsorption capacity of existing geopolymer materials, this invention proposes a geopolymer foam material with a vein-like multi-level network pore structure and its preparation method.

[0026] A typical embodiment of the present invention provides a method for preparing a geopolymer foam material with a vein-like multi-level network pore structure, comprising the following steps:

[0027] Alkali metal hydroxides were used to pretreat loofah sponge, horned melon fiber and coconut shell fiber respectively. The pretreated loofah sponge, pretreated horned melon fiber and pretreated coconut shell fiber were loaded with molybdenum catalyst and / or manganese catalyst respectively to obtain catalyst-anchored loofah sponge, catalyst-loaded horned melon fiber and catalyst-loaded coconut shell fiber respectively.

[0028] The fly ash cenospheres, metakaolin, slag, anionic surfactant, hornwort fiber supported on catalyst, and coconut shell fiber supported on catalyst are mixed evenly to obtain a mixed powder.

[0029] Mix the powder with an alkali activator to form a slurry. Add a chemical foaming agent to the slurry and mix evenly. Then inject the mixture into the loaded loofah sponge. Then, perform foaming treatment and curing treatment in sequence. Freeze-dry the cured material and calcine it at 500-800℃ under an inert atmosphere to obtain the final product.

[0030] The composition, by weight, includes 40-60 parts fly ash cenospheres, 20-30 parts metakaolin, 20-30 parts slag, 40-70 parts alkali activator, 5-10 parts total of loofah sponge anchoring catalyst, horn gourd fiber loaded with catalyst, and coconut shell fiber loaded with catalyst, 5-10 parts chemical foaming agent, and 0.4-0.8 parts anionic surfactant.

[0031] In some embodiments, the fly ash cenospheres are commercially available Grade 1 or Grade 2. The main components are SiO2 and Al2O3 (greater than 90%), containing a small amount of CaO, and are 200-400 mesh.

[0032] The metakaolin described in this invention is a common commercial grade, and in some embodiments, the metakaolin particle size is 5–20 μm. Its main components are SiO2 and Al2O3, with a content >90%.

[0033] In some embodiments, the slag is commercially available S95 or S105 grade. The particle size is controlled between 10 and 30 μm. The main components are CaO, SiO2, and Al2O3, with a mesh size of 400 to 600 mesh.

[0034] In some embodiments, the alkali activator is a sodium-based alkali activator or a potassium-based alkali activator, with a modulus of 1.2 to 1.6, and a volume fraction of sodium silicate or potassium silicate of 40 to 60%.

[0035] In some embodiments, the mass ratio of loofah sponge, horned melon fiber, and coconut shell fiber is 80-90:5-10:5-10.

[0036] The loofah sponge described in this invention is a natural loofah sponge, taken from dried common loofah, with a fiber diameter > 0.5 mm.

[0037] The horned melon fiber described in this invention is taken from dried horned melon, and the fiber length is between 1 and 3 mm.

[0038] The coconut shell fiber described in this invention has a fiber diameter of <0.1mm and a fiber length between 1 and 3mm.

[0039] In some embodiments, the chemical foaming agent is hydrogen peroxide or aluminum powder paste. Preferably, the hydrogen peroxide has a mass fraction of 3-5%. Preferably, the aluminum powder paste has a particle size of 15-30 μm and an active aluminum content of ≥75%.

[0040] In some embodiments, the anionic surfactant is an anionic surfactant such as sodium dodecyl sulfonate, sodium oleate, sodium dodecylbenzene sulfonate, or sodium dodecyl sulfate.

[0041] In some embodiments, the pretreatment process is as follows: soaking the loofah sponge, horned melon fiber or coconut shell fiber in hot water until softened, drying it, immersing it in an alkali metal hydroxide solution for treatment, and then taking it out to wash and dry.

[0042] In some embodiments, a molybdenum catalyst is supported on the pretreated loofah sponge. Specifically, the pretreated loofah sponge, thiourea (CH4N2S), and sodium molybdate (Na2MoO4) are added to water and dispersed evenly, and a hydrothermal reaction is carried out at 150–200°C. The product is then washed after the reaction. The hydrothermal reaction described in this invention refers to a reaction system under closed-loop conditions, using water as a solvent, and heating to form a high-temperature and high-pressure reaction system. Preferably, the mass ratio of the pretreated loofah sponge, CH4N2S, and Na2MoO4 is 1:14–16:4–6. Preferably, the hydrothermal reaction time is 5–7 hours.

[0043] In some embodiments, the pretreated horned melon fiber is loaded with a manganese catalyst. Specifically, the pretreated horned melon fiber is immersed in a potassium permanganate solution for 8–12 hours, washed, and dried to obtain the catalyst.

[0044] In some embodiments, the pretreated coconut shell fiber is loaded with a manganese catalyst. Specifically, the pretreated coconut shell fiber is immersed in a potassium permanganate solution for 8–12 hours, washed, and dried to obtain the catalyst.

[0045] In some embodiments, the loofah sponge anchored with the catalyst is cut into small pieces with the same area as the selected mold, stacked to fill the entire mold, and a slurry containing a chemical foaming agent is injected into the mold. The volume of the slurry containing the chemical foaming agent is 60-70% of the mold volume.

[0046] In some embodiments, the foaming treatment is performed at room temperature for 30 to 90 minutes.

[0047] In some embodiments, the curing treatment is carried out at a temperature of 40–75°C for 1–2 days.

[0048] In some embodiments, the freeze-drying conditions are -80°C for 12 to 24 hours.

[0049] In some embodiments, the calcination heating process is carried out using programmed temperature rise. The preferred heating rate is 4–6 °C / min.

[0050] In some embodiments, the cooling process after calcination is carried out using programmed cooling. The cooling rate is preferably 4–6 °C / min.

[0051] The preferred steps of the present invention are as follows:

[0052] (1) Catalyst Grid Construction: Loofah sponges are soaked in hot water to soften them fully, and the core is removed. After thorough drying with hot air, they are immersed in a sodium hydroxide solution. After soaking, they are removed, washed with ultrapure water, and thoroughly dried with hot air to obtain pretreated loofah sponges. The preferred temperature of the hot water for soaking the loofah sponges is 75–85°C. The preferred soaking time is 18–36 hours. The concentration of the sodium hydroxide solution is 9–11% (mass percentage). The soaking time in the sodium hydroxide solution is 1–3 hours. The preferred temperature of the hot air used for drying is 55–65°C.

[0053] Pretreated horned melon fibers are softened by soaking them in hot water, dried thoroughly with hot air, and then immersed in a sodium hydroxide solution. After soaking, the fibers are removed, washed with ultrapure water, and dried thoroughly with hot air to obtain pretreated horned melon fibers. The preferred temperature of the hot water for soaking the horned melon fibers is 45–55°C. The preferred soaking time is 8–12 hours. The concentration of the sodium hydroxide solution is 1–3% (mass percentage). The soaking time in the sodium hydroxide solution is 0.5–2 hours. The preferred temperature of the hot air used for drying is 55–65°C.

[0054] Coconut shell fibers are soaked in hot water to soften them completely, then dried thoroughly with hot air, and finally immersed in a sodium hydroxide solution. After soaking, they are removed, washed with ultrapure water, and dried thoroughly with hot air to obtain pretreated coconut shell fibers. The preferred temperature of the hot water for soaking the coconut shell fibers is 45–55°C. The preferred soaking time is 3–7 hours. The concentration of the sodium hydroxide solution is 1–3% (mass percentage). The soaking time in the sodium hydroxide solution is 1–3 hours. The preferred temperature of the hot air used for drying is 55–65°C.

[0055] Pretreated loofah sponge, CH4N2S and Na2MoO4 were added to ultrapure water and stirred evenly (preferably at 180 rpm for 5 h). The solution was then transferred to an autoclave and reacted at 150-200℃ for 5-7 h. After cooling, the loofah sponge was removed and washed three times with anhydrous ethanol and distilled water to obtain loofah sponge with molybdenum anchored catalyst.

[0056] Pretreated horned melon fiber or pretreated coconut shell fiber was immersed in potassium permanganate solution, stirred for 10 hours, and then removed and washed with distilled water to obtain manganese-loaded horned melon fiber or manganese-loaded coconut shell fiber.

[0057] The molybdenum-anchored catalyst loofah sponge was unfolded as an external mesh structure, cut into small pieces with the same area as the selected mold, and stacked until it filled the entire mold.

[0058] (2) Powder preparation: Weigh fly ash cenospheres, metakaolin, slag, and anionic surfactant, add 1-3 parts of manganese-loaded zucchini fiber and 1-3 parts of manganese-loaded coconut shell fiber, and mix evenly to obtain powder. Preferably, the powder is stirred at 1800-2200 rpm for 20-40 seconds using a high-speed mixer.

[0059] (3) Slurry preparation: Mix the prepared powder with the alkali activator at a ratio of 1:0.45 to 0.6, stir at 250 to 300 rpm for 3 to 6 minutes to form a fresh slurry, and then pour in the chemical foaming agent and mix for 30 to 60 seconds.

[0060] (4) Preparation of pore structure: Add chemical foaming agent to slurry and stir evenly. Fix the mold on the vibration table and pour the slurry while vibrating until it fills 2 / 3 of the mold. After foaming at room temperature for 30-90 minutes, transfer it to 40-75℃ for curing for 1-2 days.

[0061] (5) Preparation of mesoporous structure: After the material is formed, wipe off the surface moisture and transfer it to a freeze dryer to freeze dry at -80℃ for 12 to 24 hours.

[0062] (6) Preparation of vein-like network pore structure: After the material is freeze-dried, it is transferred to a tube furnace for high-temperature calcination. Under an argon atmosphere, the temperature inside the furnace is raised to 500-800℃ at a heating rate of 4-6℃ / min and held for 2 hours. Then, it is lowered to room temperature at the same rate. The residue inside the pores is washed with clean water and dried at room temperature to obtain the material.

[0063] Another embodiment of the present invention provides a geopolymer foam material having a vein-like multi-level network pore structure, obtained by the above preparation method.

[0064] A third embodiment of the present invention provides an application of the above-mentioned geopolymer foam material with a vein-like multi-level network pore structure in sewage treatment or sponge city construction.

[0065] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0066] Example 1

[0067] (1) Catalyst grid construction: Soak the loofah sponge in 80℃ hot water for 24h to soften it fully and remove the core. After drying it fully with hot air at 60℃, soak it in 10% sodium hydroxide solution for 2h. After soaking, take it out, wash it 5 times with ultrapure water, and dry it fully with hot air at 60℃ to obtain pretreated loofah sponge.

[0068] The horned melon fiber was soaked in 50℃ hot water for 10 hours to soften it fully, dried thoroughly with hot air at 60℃, then soaked in 2% sodium hydroxide solution for 1 hour. After soaking, it was taken out, washed 5 times with ultrapure water, and dried thoroughly with hot air at 60℃ to obtain pretreated horned melon fiber.

[0069] Coconut shell fibers were soaked in 50°C hot water for 5 hours to soften them fully, dried thoroughly with 60°C hot air, then immersed in 2% sodium hydroxide solution for 2 hours. After soaking, they were removed, washed 5 times with ultrapure water, and dried thoroughly with 60°C hot air to obtain pretreated coconut shell fibers.

[0070] Two parts by mass of pretreated loofah sponge, 30 parts by mass of CH4N2S, and 10 parts by mass of Na2MoO4 were diluted to ultrapure water (the mass ratio of pretreated loofah sponge to ultrapure water in the solution was 2:500, g / mL), and stirred at 180 rpm for 5 h. The solution was then transferred to an autoclave and reacted at 180 °C for 6 h. After cooling, the loofah sponge was removed, washed five times with anhydrous ethanol, and then three times with distilled water to obtain the molybdenum-anchored catalyst loofah sponge.

[0071] Pretreated horned melon fiber or pretreated coconut shell fiber was immersed in a 50 mmol / L potassium permanganate solution, stirred at 200 rpm for 10 h, and then removed and washed three times with distilled water to obtain manganese-loaded horned melon fiber or manganese-loaded coconut shell fiber.

[0072] The molybdenum-anchored catalyst loofah sponge was unfolded as an external mesh structure, cut into small pieces with the same area as the selected mold, and stacked until it filled the entire mold.

[0073] (2) Powder preparation: Take 40 parts of Grade 1 fly ash cenospheres, 30 parts of metakaolin, 30 parts of S105 slag, 0.4 parts of sodium oleate, 1 part of manganese-loaded horn gourd fiber and 1 part of manganese-loaded coconut shell fiber, and stir them with a high-speed mixer at 2000 rpm for 30 seconds before use.

[0074] (3) Slurry preparation: Mix the prepared powder with 60 parts of sodium silicate alkali activator (modulus 1.3) and stir at 285 rpm for 3-6 minutes to form a fresh slurry.

[0075] (4) Preparation of pore structure: Add 10 parts of 3% hydrogen peroxide to the slurry and stir evenly. Fix the mold on the vibration table and pour the slurry while vibrating until it fills 2 / 3 of the mold. After foaming at room temperature for 60 minutes, transfer it to 60℃ for curing for 2 days.

[0076] (5) Preparation of mesoporous structure: After the material is formed, wipe off the surface moisture and transfer it to a freeze dryer to freeze dry at -80℃ for 24 hours.

[0077] (6) Preparation of vein-like network pore structure: After the material is freeze-dried, it is transferred to a tube furnace for high-temperature calcination. Under an argon atmosphere, the temperature inside the furnace is raised to 600°C at a heating rate of 5°C / min and held for 2 hours. Then, it is lowered to room temperature at the same rate. The residue inside the pores is washed with clean water and dried at room temperature to obtain the material.

[0078] Example 2

[0079] (1) Catalyst grid construction: Soak the loofah sponge in 80℃ hot water for 24h to soften it fully and remove the core. After drying it fully with hot air at 60℃, soak it in 10% sodium hydroxide solution for 2h. After soaking, take it out, wash it 5 times with ultrapure water, and dry it fully with hot air at 60℃ to obtain pretreated loofah sponge.

[0080] The horned melon fiber was soaked in 50℃ hot water for 10 hours to soften it fully, dried thoroughly with hot air at 60℃, then soaked in 2% sodium hydroxide solution for 1 hour. After soaking, it was taken out, washed 5 times with ultrapure water, and dried thoroughly with hot air at 60℃ to obtain pretreated horned melon fiber.

[0081] Coconut shell fibers were soaked in 50°C hot water for 5 hours to soften them fully, dried thoroughly with 60°C hot air, then immersed in 2% sodium hydroxide solution for 2 hours. After soaking, they were removed, washed 5 times with ultrapure water, and dried thoroughly with 60°C hot air to obtain pretreated coconut shell fibers.

[0082] Two parts by mass of pretreated loofah sponge, 30 parts by mass of CH4N2S, and 10 parts by mass of Na2MoO4 were diluted to ultrapure water (the mass ratio of pretreated loofah sponge to ultrapure water in the solution was 2:500, g / mL), and stirred at 180 rpm for 5 h. The solution was then transferred to an autoclave and reacted at 180 °C for 6 h. After cooling, the loofah sponge was removed, washed five times with anhydrous ethanol, and then three times with distilled water to obtain the molybdenum-anchored catalyst loofah sponge.

[0083] Pretreated horned melon fiber or pretreated coconut shell fiber was immersed in a 50 mmol / L potassium permanganate solution, stirred at 200 rpm for 10 h, and then removed and washed three times with distilled water to obtain manganese-loaded horned melon fiber or manganese-loaded coconut shell fiber.

[0084] The molybdenum-anchored catalyst loofah sponge was unfolded as an external mesh structure, cut into small pieces with the same area as the selected mold, and stacked until it filled the entire mold.

[0085] (2) Powder preparation: Take 50 parts of grade 2 fly ash cenospheres, 20 parts of metakaolin, 30 parts of S95 slag, 0.1 parts of sodium oleate, 0.1 parts of sodium dodecyl sulfonate, 0.2 parts of sodium dodecylbenzene sulfonate, 1 part of manganese-loaded horn gourd fiber and 1 part of manganese-loaded coconut shell fiber, stir them with a high-speed mixer at 2000 rpm for 30 seconds and set aside.

[0086] (3) Slurry preparation: Mix the prepared powder with 60 parts of sodium silicate alkali activator (modulus 1.3) and stir at 285 rpm for 3-6 minutes to form a fresh slurry.

[0087] (4) Preparation of pore structure: Add 8 parts of 5% hydrogen peroxide to the slurry and stir evenly. Fix the mold on the vibration table and pour the slurry while vibrating until it fills 2 / 3 of the mold. After foaming at room temperature for 30 minutes, transfer it to 60℃ for curing for 2 days.

[0088] (5) Preparation of mesoporous structure: After the material is formed, wipe off the surface moisture and transfer it to a freeze dryer to freeze dry at -80℃ for 24 hours.

[0089] (6) Preparation of vein-like network pore structure: After the material is freeze-dried, it is transferred to a tube furnace for high-temperature calcination. Under an argon atmosphere, the temperature inside the furnace is raised to 700℃ at a heating rate of 5℃ / min and held for 2 hours. Then, it is lowered to room temperature at the same rate. The residue inside the pores is washed with clean water and dried at room temperature to obtain the material.

[0090] Example 3

[0091] (1) Catalyst grid construction: Soak the loofah sponge in 80℃ hot water for 24h to soften it fully and remove the core. After drying it fully with hot air at 60℃, soak it in 10% sodium hydroxide solution for 2h. After soaking, take it out, wash it 5 times with ultrapure water, and dry it fully with hot air at 60℃ to obtain pretreated loofah sponge.

[0092] The horned melon fiber was soaked in 50℃ hot water for 10 hours to soften it fully, dried thoroughly with hot air at 60℃, then soaked in 2% sodium hydroxide solution for 1 hour. After soaking, it was taken out, washed 5 times with ultrapure water, and dried thoroughly with hot air at 60℃ to obtain pretreated horned melon fiber.

[0093] Coconut shell fibers were soaked in 50°C hot water for 5 hours to soften them fully, dried thoroughly with 60°C hot air, then immersed in 2% sodium hydroxide solution for 2 hours. After soaking, they were removed, washed 5 times with ultrapure water, and dried thoroughly with 60°C hot air to obtain pretreated coconut shell fibers.

[0094] Two parts by mass of pretreated loofah sponge, 30 parts by mass of CH4N2S, and 10 parts by mass of Na2MoO4 were diluted to ultrapure water (the mass ratio of pretreated loofah sponge to ultrapure water in the solution was 2:500, g / mL), and stirred at 180 rpm for 5 h. The solution was then transferred to an autoclave and reacted at 180 °C for 6 h. After cooling, the loofah sponge was removed, washed five times with anhydrous ethanol, and then three times with distilled water to obtain the molybdenum-anchored catalyst loofah sponge.

[0095] Pretreated horned melon fiber or pretreated coconut shell fiber was immersed in a 50 mmol / L potassium permanganate solution, stirred at 200 rpm for 10 h, and then removed and washed three times with distilled water to obtain manganese-loaded horned melon fiber or manganese-loaded coconut shell fiber.

[0096] The molybdenum-anchored catalyst loofah sponge was unfolded as an external mesh structure, cut into small pieces with the same area as the selected mold, and stacked until it filled the entire mold.

[0097] (2) Powder preparation: Take 50 parts of Grade 1 fly ash cenospheres, 30 parts of metakaolin, 20 parts of S95 slag, 0.1 parts of sodium oleate, 0.1 parts of sodium dodecyl sulfate, 0.2 parts of sodium dodecylbenzene sulfonate, 1 part of manganese-loaded horn gourd fiber and 1 part of manganese-loaded coconut shell fiber, stir them with a high-speed mixer at 2000 rpm for 30 seconds and set aside.

[0098] (3) Slurry preparation: Mix the prepared powder with 60 parts of potassium silicate alkali activator (modulus 1.3) and stir at 285 rpm for 3-6 minutes to form a fresh slurry.

[0099] (4) Preparation of pore structure: Add 5 parts of 7% hydrogen peroxide to the slurry and stir evenly. Fix the mold on the vibration table and pour the slurry while vibrating until it fills 2 / 3 of the mold. After foaming at room temperature for 30 minutes, transfer it to 70℃ for curing for 2 days.

[0100] (5) Preparation of mesoporous structure: After the material is formed, wipe off the surface moisture and transfer it to a freeze dryer to freeze dry at -80℃ for 16h.

[0101] (6) Preparation of vein-like network pore structure: After the material is freeze-dried, it is transferred to a tube furnace for high-temperature calcination. Under an argon atmosphere, the temperature inside the furnace is raised to 800℃ at a heating rate of 4℃ / min and held for 2 hours. Then, it is lowered to room temperature at the same rate. The residue inside the pores is washed with clean water and dried at room temperature to obtain the material.

[0102] Comparative Example 1

[0103] (1) Catalyst grid construction: Soak the loofah sponge in 80℃ hot water for 24h to soften it fully and remove the core. After drying it fully with hot air at 60℃, soak it in 10% sodium hydroxide solution for 2h. After soaking, take it out, wash it 5 times with ultrapure water, and dry it fully with hot air at 60℃ to obtain pretreated loofah sponge.

[0104] Two parts by mass of pretreated loofah sponge, 30 parts by mass of CH4N2S, and 10 parts by mass of Na2MoO4 were diluted to ultrapure water (the mass ratio of pretreated loofah sponge to ultrapure water in the solution was 2:500, g / mL), and stirred at 180 rpm for 5 h. The solution was then transferred to an autoclave and reacted at 180 °C for 6 h. After cooling, the loofah sponge was removed, washed five times with anhydrous ethanol, and then three times with distilled water to obtain the molybdenum-anchored catalyst loofah sponge.

[0105] The molybdenum-anchored catalyst loofah sponge was unfolded as an external mesh structure, cut into small pieces with the same area as the selected mold, and stacked until it filled the entire mold.

[0106] (2) Powder preparation: Take 50 parts of grade 2 fly ash cenospheres, 20 parts of metakaolin, 30 parts of S95 slag, 0.1 parts of sodium oleate, 0.1 parts of sodium dodecyl sulfonate, and 0.2 parts of sodium dodecylbenzene sulfonate. Stir them with a high-speed mixer at 2000 rpm for 30 seconds and set aside.

[0107] (3) Slurry preparation: Mix the prepared powder with 60 parts of sodium silicate alkali activator (modulus 1.3) and stir at 285 rpm for 3-6 minutes to form a fresh slurry.

[0108] (4) Preparation of pore structure: Add 8 parts of 5% hydrogen peroxide to the slurry and stir evenly. Fix the mold on the vibration table and pour the slurry while vibrating until it fills 2 / 3 of the mold. After foaming at room temperature for 30 minutes, transfer it to 60℃ for curing for 2 days.

[0109] (5) Preparation of mesoporous structure: After the material is formed, wipe off the surface moisture and transfer it to a freeze dryer to freeze dry at -80℃ for 24 hours.

[0110] (6) Preparation of vein-like network pore structure: After the material is freeze-dried, it is transferred to a tube furnace for high-temperature calcination. Under an argon atmosphere, the temperature inside the furnace is raised to 700℃ at a heating rate of 5℃ / min and held for 2 hours. Then, it is lowered to room temperature at the same rate. The residue inside the pores is washed with clean water and dried at room temperature to obtain the material.

[0111] Comparative Example 2

[0112] (1) Catalyst grid construction: The horned melon fiber was soaked in hot water at 50℃ for 10h to soften it fully. After being dried with hot air at 60℃, it was soaked in 2% sodium hydroxide solution for 1h. After being taken out, it was washed 5 times with ultrapure water and dried with hot air at 60℃ to obtain pretreated horned melon fiber.

[0113] Coconut shell fibers were soaked in 50°C hot water for 5 hours to soften them fully, dried thoroughly with 60°C hot air, then immersed in 2% sodium hydroxide solution for 2 hours. After soaking, they were removed, washed 5 times with ultrapure water, and dried thoroughly with 60°C hot air to obtain pretreated coconut shell fibers.

[0114] Pretreated horned melon fiber or pretreated coconut shell fiber was immersed in a 50 mmol / L potassium permanganate solution, stirred at 200 rpm for 10 h, and then removed and washed three times with distilled water to obtain manganese-loaded horned melon fiber or manganese-loaded coconut shell fiber.

[0115] (2) Powder preparation: Take 50 parts of grade 2 fly ash cenospheres, 20 parts of metakaolin, 30 parts of S95 slag, 0.1 parts of sodium oleate, 0.1 parts of sodium dodecyl sulfonate, 0.2 parts of sodium dodecylbenzene sulfonate, 1 part of manganese-loaded horn gourd fiber and 1 part of manganese-loaded coconut shell fiber, stir them with a high-speed mixer at 2000 rpm for 30 seconds and set aside.

[0116] (3) Slurry preparation: Mix the prepared powder with 60 parts of sodium silicate alkali activator (modulus 1.3) and stir at 285 rpm for 3-6 minutes to form a fresh slurry.

[0117] (4) Preparation of pore structure: Add 8 parts of 5% hydrogen peroxide to the slurry and stir evenly. Fix the mold on the vibration table and pour the slurry while vibrating until it fills 2 / 3 of the mold. After foaming at room temperature for 30 minutes, transfer it to 60℃ for curing for 2 days.

[0118] (5) Preparation of mesoporous structure: After the material is formed, wipe off the surface moisture and transfer it to a freeze dryer to freeze dry at -80℃ for 24 hours.

[0119] (6) Preparation of vein-like network pore structure: After the material is freeze-dried, it is transferred to a tube furnace for high-temperature calcination. Under an argon atmosphere, the temperature inside the furnace is raised to 700℃ at a heating rate of 5℃ / min and held for 2 hours. Then, it is lowered to room temperature at the same rate. The residue inside the pores is washed with clean water and dried at room temperature to obtain the material.

[0120] Comparative Example 3

[0121] (1) Catalyst grid construction: Soak the loofah sponge in 80℃ hot water for 24h to soften it fully and remove the core. After drying it fully with hot air at 60℃, soak it in 10% sodium hydroxide solution for 2h. After soaking, take it out, wash it 5 times with ultrapure water, and dry it fully with hot air at 60℃ to obtain pretreated loofah sponge.

[0122] The horned melon fiber was soaked in 50℃ hot water for 10 hours to soften it fully, dried thoroughly with hot air at 60℃, then soaked in 2% sodium hydroxide solution for 1 hour. After soaking, it was taken out, washed 5 times with ultrapure water, and dried thoroughly with hot air at 60℃ to obtain pretreated horned melon fiber.

[0123] Coconut shell fibers were soaked in 50°C hot water for 5 hours to soften them fully, dried thoroughly with 60°C hot air, then immersed in 2% sodium hydroxide solution for 2 hours. After soaking, they were removed, washed 5 times with ultrapure water, and dried thoroughly with 60°C hot air to obtain pretreated coconut shell fibers.

[0124] Two parts by mass of pretreated loofah sponge, 30 parts by mass of CH4N2S, and 10 parts by mass of Na2MoO4 were diluted to ultrapure water (the mass ratio of pretreated loofah sponge to ultrapure water in the solution was 2:500, g / mL), and stirred at 180 rpm for 5 h. The solution was then transferred to an autoclave and reacted at 180 °C for 6 h. After cooling, the loofah sponge was removed, washed five times with anhydrous ethanol, and then three times with distilled water to obtain the molybdenum-anchored catalyst loofah sponge.

[0125] Pretreated horned melon fiber or pretreated coconut shell fiber was immersed in a 50 mmol / L potassium permanganate solution, stirred at 200 rpm for 10 h, and then removed and washed three times with distilled water to obtain manganese-loaded horned melon fiber or manganese-loaded coconut shell fiber.

[0126] The molybdenum-anchored catalyst loofah sponge was unfolded as an external mesh structure, cut into small pieces with the same area as the selected mold, and stacked until it filled the entire mold.

[0127] (2) Powder preparation: Take 50 parts of grade 2 fly ash cenospheres, 20 parts of metakaolin, 30 parts of S95 slag, 0.1 parts of sodium oleate, 0.1 parts of sodium dodecyl sulfonate, 0.2 parts of sodium dodecylbenzene sulfonate, 1 part of manganese-loaded horn gourd fiber and 1 part of manganese-loaded coconut shell fiber, stir them with a high-speed mixer at 2000 rpm for 30 seconds and set aside.

[0128] (3) Slurry preparation: Mix the prepared powder with 60 parts of sodium silicate alkali activator (modulus 1.3) and stir at 285 rpm for 3-6 minutes to form a fresh slurry.

[0129] (4) Preparation of pore structure: Add 8 parts of 5% hydrogen peroxide to the slurry and stir evenly. Fix the mold on the vibration table and pour the slurry while vibrating until it fills 2 / 3 of the mold. After foaming at room temperature for 30 minutes, transfer it to 60℃ for curing for 2 days.

[0130] Table 1. Pore Structure of Materials in Examples and Comparative Examples

[0131]

[0132] Table 2. Adsorption performance of materials in the examples and comparative examples

[0133] Serial Number <![CDATA[Pb 2+ Removal rate Methylene blue removal rate E. coli removal rate Perfluorooctanoic acid removal rate Example 1 98.10％ 96.30％ 89.30％ 78.9.3％ Example 2 99.30％ 99.10％ 93.30％ 77.20％ Example 3 99.10％ 96.80％ 92.10％ 75.30％ Comparative Example 1 95.30％ 92.80％ 89.20％ 53.13％ Comparative Example 2 72.81％ 66.25％ 57.33％ 14.25％ Comparative Example 3 94.32％ 90.22％ 64.51％ 68.9％

[0134] Pb 2+ The removal rate refers to the removal of Pb at a concentration of 200 mg / L for a 1.5 g / L sample. 2+ The removal rate of the solution over 2 hours;

[0135] The removal rate of methylene blue refers to the removal rate of a 200 mg / L methylene blue solution from a 1.5 g / L sample over 2 hours.

[0136] The removal rate of E. coli refers to a colony concentration of 5 × 10⁻⁶. 9 Initial removal rate of E. coli culture medium of 1 / L through a d6×10cm column;

[0137] The removal rate of perfluorooctanoic acid (PFOA) refers to the removal rate of a PFOA solution with a concentration of 50 mg / L and a sample concentration of 1.5 g / L over 2 hours.

[0138] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a geopolymer foam material with a vein-like multi-level network pore structure, characterized in that, Includes the following steps: Alkali metal hydroxides were used to pretreat loofah sponge, horned melon fiber and coconut shell fiber respectively; Pretreated loofah sponge, CH4N2S, and Na2MoO4 were added to water and dispersed evenly. A hydrothermal reaction was carried out at 150~200 ℃. After the reaction, the loofah sponge anchored with molybdenum catalyst was obtained by washing. The pretreated horned melon fiber was immersed in potassium permanganate solution for 8-12 hours, washed and dried to obtain horned melon fiber loaded with manganese catalyst. The pretreated coconut shell fiber was immersed in potassium permanganate solution for 8-12 hours, washed and dried to obtain coconut shell fiber loaded with manganese catalyst. The fly ash cenospheres, metakaolin, slag, anionic surfactant, manganese-catalyst-supported horn gourd fiber, and manganese-catalyst-supported coconut shell fiber are mixed evenly to obtain a mixed powder. The mixed powder and alkali activator are mixed to form a slurry. A chemical foaming agent is added to the slurry and mixed evenly. The mixture is then injected into the loofah sponge anchored with molybdenum catalyst. Then, foaming treatment and curing treatment are carried out in sequence. The cured material is freeze-dried, and then calcined at 500-800℃ under an inert atmosphere to obtain the final product. The composition, by weight, includes 40-60 parts fly ash cenospheres, 20-30 parts metakaolin, 20-30 parts slag, 40-70 parts alkali activator, 5-10 parts total of loofah sponge anchored with molybdenum catalyst, horn gourd fiber supported with manganese catalyst, and coconut shell fiber supported with manganese catalyst, 5-10 parts chemical foaming agent, and 0.4-0.8 parts anionic surfactant.

2. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 1, characterized in that, The metakaolin has a particle size of 5~20μm; Alternatively, the slag particle size is 10~30μm.

3. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 1, characterized in that, The alkaline activator is a sodium-based or potassium-based alkaline activator with a modulus of 1.2 to 1.6 and a volume fraction of sodium silicate or potassium silicate of 40 to 60%. Alternatively, the chemical foaming agent may be hydrogen peroxide or aluminum powder paste; Alternatively, the anionic surfactant may be one or more of sodium dodecyl sulfonate, sodium oleate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate.

4. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 3, characterized in that, The hydrogen peroxide has a mass fraction of 3-5%.

5. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 3, characterized in that, The aluminum powder paste has a particle size of 15~30μm and an active aluminum content of ≥75%.

6. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 1, characterized in that, The mass ratio of loofah sponge, horned melon fiber, and coconut shell fiber is 80~90:5~10:5~10.

7. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 1, characterized in that, The pretreatment process is as follows: soak the loofah sponge, horned melon fiber or coconut shell fiber in hot water until softened, dry it, and then immerse it in an alkali metal hydroxide solution for treatment. Finally, take it out, wash it, and dry it.

8. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 1, characterized in that, The mass ratio of pretreated loofah sponge, CH4N2S, and Na2MoO4 was 1:14~16:4~6.

9. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 1, characterized in that, The hydrothermal reaction time is 5-7 hours.

10. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 1, characterized in that, Cut the loofah sponge anchored to the molybdenum catalyst into small pieces of the same area as the selected mold, stack them to fill the entire mold, and inject a slurry with added chemical foaming agent into the mold.

11. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 10, characterized in that, The volume of the slurry with added chemical foaming agent is 60-70% of the mold volume.

12. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 1, characterized in that, The foaming treatment was carried out at room temperature for 30-90 minutes. Alternatively, the curing temperature should be 40~75℃, and the time should be 1~2 days; Alternatively, the freeze-drying conditions are -80℃ for 12~24 h; Alternatively, the calcination heating process may be carried out using programmed heating; Alternatively, the cooling process after calcination can be carried out using programmed cooling.

13. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 12, characterized in that, The heating rate used in the calcination process is 4~6 ℃ / min.

14. The method for preparing geopolymer foam material with a vein-like multi-level network pore structure as described in claim 12, characterized in that, The cooling process after calcination adopts a cooling rate of 4~6 ℃ / min.

15. A geopolymer foam material with a vein-like multi-level network pore structure, characterized in that, Obtained by the preparation method according to any one of claims 1 to 14.

16. The application of a geopolymer foam material with a vein-like multi-level network pore structure as described in claim 15 in wastewater, flue gas treatment, or sponge city construction.

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