A porous lignin fiber adsorption material and a production process thereof

Abstract

The present application belongs to the field of adsorbing material, discloses a kind of porous lignin fiber adsorbing material and its production process, including the following by weight parts of raw materials: lignin fiber 40-60 parts, bamboo fiber 20-30 parts, chitosan 5-15 parts, sodium bicarbonate 5-10 parts, attapulgite 5-10 parts, zeolite 5-10 parts, magnetic nano-particle 2-5 parts;The present application is intended to provide a kind of production process of porous lignin fiber adsorbing material, through innovative raw material formula and optimized production process, solve the problems such as poor pore structure, limited adsorption performance, separation difficulty of existing lignin fiber adsorbing material, realize the efficient adsorption of light component in asphalt, enhance the stability of asphalt mixture, while the efficient adsorption and rapid separation of heavy metal ions, organic pollutants etc., while reducing production energy consumption, improve the environmental protection and economy of process.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, specifically to a porous lignin fiber adsorption material and its production process. Background Technology

[0002] Lignin fiber, a natural polymer material derived from biomass, is widely used as a reinforcing filler in asphalt pavement engineering due to its wide availability, low cost, and certain physical and mechanical properties. It is used to improve the high-temperature stability and fatigue resistance of asphalt mixtures. However, with the development of environmental protection technologies, the application potential of lignin fiber in environmental remediation (such as pollutant adsorption) is gradually attracting attention.

[0003] First, the pore structure is not ideal, with low porosity and uneven pore size distribution, resulting in a small specific surface area, which limits its ability to adsorb pollutants.

[0004] Secondly, it has poor adsorption selectivity, making it difficult to achieve efficient adsorption of specific pollutants;

[0005] Third, the separation and recycling of adsorbent materials after use is difficult, and it usually requires energy-intensive and inefficient methods such as centrifugation and filtration, which limits their large-scale application.

[0006] Currently, although some studies have improved lignin fiber adsorbent materials by adding pore-forming agents and optimizing carbonization activation processes, the aforementioned problems have not been fundamentally solved. For example, while some existing adsorbent materials can increase porosity, they do not effectively improve pore size distribution, and there is a lack of in-depth development of the functionalization of adsorbent materials, failing to meet the demands for efficient, specific adsorption and convenient separation in complex environments. Therefore, how to directionally modify lignin fibers used in asphalt pavements into high-porosity, highly selective, and easily separable adsorbent materials, while reducing production energy consumption, has become a key technological bottleneck for expanding its environmental applications. This invention systematically solves the above problems through innovative raw material formulation (introducing functional components such as zeolite and magnetic nanoparticles) and optimized processes (freeze-drying + catalytic activation), opening up a new path for the high-value utilization of lignin fibers. Summary of the Invention

[0007] This invention aims to provide a production process for porous lignin fiber adsorbent materials. Through innovative raw material formulation and optimized production process, it solves the problems of poor pore structure, limited adsorption performance, and difficult separation of existing lignin fiber adsorbent materials, achieving efficient adsorption of lightweight components in asphalt, enhancing the stability of asphalt mixtures, and simultaneously achieving efficient adsorption and rapid separation of heavy metal ions, organic pollutants, etc., while reducing production energy consumption and improving the environmental friendliness and economy of the process.

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

[0009] The technical solution provided by this invention is: a porous lignin fiber adsorbent material, comprising the following raw materials in parts by weight: 40-60 parts of lignin fiber, 20-30 parts of bamboo fiber, 5-15 parts of chitosan, 5-10 parts of sodium bicarbonate, 5-10 parts of attapulgite, 5-10 parts of zeolite, and 2-5 parts of magnetic nanoparticles.

[0010] The porous lignin fiber adsorbent material has a porosity of 80%-85%, a specific surface area of ​​600-800 m² / g, an average pore size of 10-30 nm, an adsorption capacity for lead ions ≥150 mg / g, and a saturation magnetization ≥30 emu / g.

[0011] Furthermore, the magnetic nanoparticles are Fe3O4 nanoparticles with a particle size of 10-30 nm.

[0012] Furthermore, the zeolite is clinoptilolite with a particle size of 200-500 mesh and a silicon-to-aluminum ratio (SiO2 / Al2O3) of 5-10.

[0013] Furthermore, the degree of deacetylation of chitosan is 80%-95%.

[0014] Furthermore, a production process for a porous lignin fiber adsorbent material includes the following steps:

[0015] S1: Immerse lignin fiber and bamboo fiber separately in a 5%-10% sodium hydroxide solution at 50-70℃ for 2-4 hours, wash until neutral and dry to obtain pretreated lignin fiber and pretreated bamboo fiber.

[0016] S2: Add the pretreated lignin fiber, pretreated bamboo fiber, chitosan, sodium bicarbonate, attapulgite, zeolite and magnetic nanoparticles to a mixer and disperse them under 200W ultrasonic conditions for 10 minutes to obtain a mixture.

[0017] S3: Add deionized water to the mixture to a humidity of 50%-60%, granulate, freeze dry at -50℃ and 10Pa for 24 hours to obtain precursor particles with a particle size of 2-5mm, and obtain carbonized products.

[0018] S4: Heat the precursor particles to 300-400℃ at 5-10℃ / min under nitrogen protection and hold for 1-2 hours.

[0019] S5: Mix the carbonization product with the Pt-Co single-atom catalyst at a mass ratio of 100:1-3, and heat it to 500-600℃ at a rate of 10-15℃ / min in a water vapor atmosphere (flow rate 0.5-1.5L / min) for 2-3 hours to obtain activated particles;

[0020] S6: Wash the activated particles until neutral, and dry them at 80-100℃ for 6-8 hours to obtain the target product.

[0021] Furthermore, in S5, the Pt-Co single-atom catalyst has a Pt loading of 0.5-2 wt% and a Co loading of 1-3 wt%, with activated carbon as the catalyst support.

[0022] Furthermore, the inert gas in S4 is nitrogen or argon, and the gas flow rate is 1-2 L / min.

[0023] Furthermore, the magnetic nanoparticles in S2 were prepared via an in-situ co-precipitation method, including: [details about Fe]. 2+ and Fe 3+ Fe3O4 nanoparticles were obtained by dissolving the nanoparticles in deionized water at a molar ratio of 1:2, adding ammonia dropwise at 70-80℃ and pH=10 until precipitation was complete, centrifuging, washing, and drying.

[0024] The beneficial effects of this technical solution are:

[0025] (1) By introducing clinoptilolite and Fe3O4 nanoparticles, a “zeolite-attapulgite multi-level channel + magnetic core-shell structure” is formed. The micropores of zeolite and the mesopores of attapulgite work together to increase the proportion of 10-30nm pore size to 85%, which greatly improves the specific surface area and adsorption sites of the material. Fe3O4 nanoparticles are uniformly loaded on the fiber surface through in-situ co-precipitation, which endows the material with magnetic response characteristics and enables rapid separation within 30 seconds under a magnetic field. Compared with traditional lignin fiber adsorption materials, the material of this invention has improved adsorption capacity for lead ions and significantly improved adsorption capacity for organic pollutants such as phenol, and its reusability is enhanced.

[0026] (2) The ice crystal template formed by the freeze-drying step increases the porosity of the material from 75% to 85% in the existing technology, increases the proportion of macropores by 30%, significantly improves the mass transfer efficiency, and increases the adsorption kinetic constant k2 to 0.05 g / (mg・min); the catalytic activation stage uses a Pt-Co single-atom catalyst to achieve deep pore etching at a low temperature of 500-600℃, increasing the specific surface area to 600-800 m² / g, reducing energy consumption by 30% compared with the traditional activation process. At the same time, the catalyst promotes the generation of phenolic hydroxyl and carboxyl groups on the surface, further enhancing the adsorption performance of the material.

[0027] (3) The raw materials of this invention are all renewable or natural materials. There are no harmful pollutant emissions during the production process, which meets the environmental protection requirements. The optimization of the process reduces energy consumption and production costs. Moreover, the high efficiency and reusability of the adsorption material make it more cost-effective in practical applications and have broad market application prospects. Attached Figure Description

[0028] Figure 1 Example 1 of the production process of a porous lignin fiber adsorbent material proposed in this invention is shown in the data table.

[0029] Figure 2 Example 2 data table of the production process of a porous lignin fiber adsorbent material proposed in this invention;

[0030] Figure 3 Example 3 data table for the production process of a porous lignin fiber adsorbent material proposed in this invention;

[0031] Figure 4 This invention presents a comparative performance table showing the differences in raw material composition during the production process of a porous lignin fiber adsorbent material.

[0032] Figure 5 This is a data table showing the influence of process parameter differences on pore structure in the production process of a porous lignin fiber adsorbent material proposed in this invention.

[0033] Figure 6 Comparative Example 1 data table showing the production process of a porous lignin fiber adsorbent material proposed in this invention;

[0034] Figure 7 Comparative Example 2 data table for the production process of a porous lignin fiber adsorbent material proposed in this invention;

[0035] Figure 8 Comparative Example 3 data table shows the production process of a porous lignin fiber adsorbent material proposed in this invention.

[0036] Figure 9 Comparative Examples 1-3 data tables show the production process of a porous lignin fiber adsorbent material proposed in this invention.

[0037] Figure 10 This table shows the core differences between the comparative examples and the embodiments of the production process of the porous lignin fiber adsorbent material proposed in this invention.

[0038] Figure 11 Table showing the differences between embodiments and comparative examples of the production process of a porous lignin fiber adsorbent material proposed in this invention; Figure 12 This table compares experimental data from examples and comparative examples of the production process of the porous lignin fiber adsorbent material proposed in this invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0040] The specific implementation process is as follows:

[0041] Example 1:

[0042] Please see Figure 1-12 The present invention provides a technical solution: a production process for porous lignin fiber adsorbent materials, comprising the following steps:

[0043] S1: Weigh 40 kg of lignin fiber and 20 kg of bamboo fiber, and place them separately into two corrosion-resistant containers. Add a 5% sodium hydroxide solution to each container, ensuring the solution volume completely submerges the fiber. Place the containers in a constant temperature water bath at 50°C and soak for 2 hours. After soaking, wash the fiber multiple times with deionized water until the pH of the washing solution is 7. Transfer the washed fiber to a forced-air drying oven and dry it at 80°C until constant weight. Remove it for later use to obtain pretreated lignin fiber and pretreated bamboo fiber.

[0044] S2: Add the pretreated lignin fiber, pretreated bamboo fiber, 5kg chitosan, 5kg sodium bicarbonate, 5kg attapulgite, 5kg clinoptilolite (200 mesh, silica-alumina ratio 5) and 2kg Fe3O4 nanoparticles (particle size 10nm) to a mixer, turn on the mixer and stir at 200r / min for 5 minutes. After preliminary mixing, place the mixer in an ultrasonic device and disperse it at 200W ultrasonic power for 10 minutes to obtain the mixture.

[0045] S3: Slowly add deionized water to the mixture while stirring. Use a humidity detector to monitor the humidity of the material in real time until the humidity reaches 50%. Use a granulator to make the wet material into granules with a particle size of 2mm. Spread the granules evenly on a freeze drying tray and put it into a freeze dryer. Freeze dry at -50℃ and 10Pa for 24 hours to obtain precursor granules.

[0046] S4: Transfer the precursor particles to a tube furnace, introduce nitrogen gas at a flow rate of 1L / min, raise the temperature of the tube furnace to 300℃ at a heating rate of 5℃ / min, hold at this temperature for 1 hour, and perform carbonization treatment; after carbonization, turn off the heating device, continue to introduce nitrogen gas until the temperature of the tube furnace drops to room temperature, and take out the carbonization product.

[0047] S5: The carbonization product and Pt-Co single-atom catalyst (Pt loading 0.5wt%, Co loading 1wt%, with activated carbon as support) are mixed evenly at a mass ratio of 100:1, placed in an activation furnace, and steam is introduced at a flow rate of 0.5L / min. The mixture is heated to 500℃ at a heating rate of 10℃ / min and held at this temperature for 2 hours to perform activation treatment and obtain activated particles.

[0048] S6: The activated granules are repeatedly washed with deionized water until the pH of the washing solution is 7 to remove the activator and impurities remaining on the surface of the granules; then the granules are placed in a forced-air drying oven and dried at 80°C for 6 hours to obtain porous lignin fiber adsorbent material.

[0049] Example 2:

[0050] Please see Figure 1-12 The present invention provides a technical solution: a production process for a porous lignin fiber adsorbent material, comprising the following steps:

[0051] S1: Weigh 50kg of lignin fiber and 25kg of bamboo fiber, place them separately in corrosion-resistant containers, add 8% sodium hydroxide solution, and soak them in a constant temperature water bath at 60℃ for 3 hours; after soaking, wash the fibers repeatedly with deionized water until the washing solution is neutral, put the fibers into a forced-air drying oven, and dry them at 80℃ to constant weight for later use, to obtain pretreated lignin fiber and pretreated bamboo fiber;

[0052] S2: Add the pretreated lignin fiber, pretreated bamboo fiber, 10kg chitosan, 8kg sodium bicarbonate, 8kg attapulgite, 8kg clinoptilolite (300 mesh, silica-alumina ratio 8) and 3kg Fe3O4 nanoparticles (particle size 20nm) to a mixer, stir at 200r / min for 5 minutes, and then disperse under 200W ultrasonic power for 10 minutes to obtain a mixture.

[0053] S3: Add deionized water to the mixture and stir until the humidity reaches 55%. Use a granulator to form particles with a particle size of 3 mm. Place the particles in a freeze dryer and freeze dry them at -50℃ and 10 Pa for 24 hours to obtain precursor particles.

[0054] S4: Place the precursor particles into a tube furnace, introduce nitrogen (flow rate 1.5L / min), heat to 350℃ at a heating rate of 8℃ / min, and hold for 1.5 hours for carbonization; after carbonization, wait for the temperature to drop to room temperature and remove the carbonized product.

[0055] S5: The carbonization product is mixed with a Pt-Co single-atom catalyst (Pt loading 1wt%, Co loading 2wt%, with activated carbon as support) at a mass ratio of 100:2, placed in an activation furnace, and steam (flow rate 1L / min) is introduced and heated to 550℃ at a heating rate of 12℃ / min. The mixture is then kept at this temperature for 2.5 hours to activate the product and obtain the activated particles.

[0056] S6: The activated particles are washed with deionized water until neutral, and dried in a 90℃ forced-air drying oven for 7 hours to obtain porous lignin fiber adsorbent material.

[0057] Example 3:

[0058] Please see Figure 1-12 The present invention provides a technical solution: a production process for a porous lignin fiber adsorbent material, comprising the following steps:

[0059] S1: Weigh 60kg of lignin fiber and 30kg of bamboo fiber, add 10% sodium hydroxide solution to each, and soak in a 70℃ constant temperature water bath for 4 hours; after soaking, wash the fiber with deionized water until neutral, and dry it in an 80℃ forced-air drying oven to constant weight for later use, to obtain pretreated lignin fiber and pretreated bamboo fiber.

[0060] S2: Add the pretreated lignin fiber, pretreated bamboo fiber, 15kg chitosan, 10kg sodium bicarbonate, 10kg attapulgite, 10kg clinoptilolite (500 mesh, silica-alumina ratio 10) and 5kg Fe3O4 nanoparticles (particle size 30nm) to a mixer, stir for 5 minutes, and then disperse under 200W ultrasonication for 10 minutes to obtain a mixture.

[0061] S3: Add deionized water to the mixture and stir until the humidity is 60%. Use a granulator to form particles with a particle size of 5 mm. Freeze-dry at -50℃ and 10 Pa for 24 hours to obtain precursor particles.

[0062] S4: Place the precursor particles into a tube furnace, introduce nitrogen (flow rate 2L / min), heat to 400℃ at a heating rate of 10℃ / min, hold for 2 hours for carbonization; after carbonization is completed, cool down and remove the carbonized product.

[0063] S5: The carbonization product is mixed with a Pt-Co single-atom catalyst (Pt loading 2wt%, Co loading 3wt%, with activated carbon as support) at a mass ratio of 100:3, placed in an activation furnace, and steam (flow rate 1.5L / min) is introduced. The mixture is heated to 600℃ at a heating rate of 15℃ / min and kept at that temperature for 3 hours to obtain activated particles.

[0064] S6: The activated particles are washed with deionized water until neutral, and dried in a 100℃ forced-air drying oven for 8 hours to obtain porous lignin fiber adsorbent material.

[0065] Please see Figure 1-12 The present invention provides a comparative example 1 (zeolite and magnetic particles are omitted, and a traditional activation process is used).

[0066] Raw material composition (parts by weight): lignin fiber 40, bamboo fiber 20, chitosan 5, sodium bicarbonate 5, attapulgite 5 (no zeolite, no Fe3O4 nanoparticles).

[0067] Production process

[0068] S1: Soak 40 kg of lignin fiber and 20 kg of bamboo fiber in a 5% sodium hydroxide solution at 50°C for 2 hours, wash with deionized water until neutral, and dry at 80°C to constant weight (exactly the same as in Example 1).

[0069] S2: Add the pretreated lignin fiber, bamboo fiber, 5kg chitosan, 5kg sodium bicarbonate, and 5kg attapulgite to a mixer and stir at 200r / min for 5 minutes (no ultrasonic dispersion, no zeolite / magnetic particle addition); add deionized water to the mixture and stir until the moisture content is 50%, then use a conventional granulator (non-freeze granulation) to produce 2mm particles (no freeze drying, direct granulation);

[0070] S3: Place the particles into a tube furnace, introduce nitrogen gas (flow rate 1L / min), heat to 300°C at 5°C / min, and hold for 1 hour (same as in Example 1).

[0071] S4: Using the traditional KOH activation method: the carbonization product and potassium hydroxide are mixed at a mass ratio of 1:1 (without Pt-Co catalyst), placed in an activation furnace, and heated to 600℃ at 10℃ / min (100℃ higher than the example), and kept at this temperature for 2 hours in a water vapor atmosphere (flow rate 0.5L / min);

[0072] S5: Wash with deionized water until neutral, and dry at 80°C for 6 hours (same as in Example 1);

[0073] Due to the lack of zeolite and magnetic particles, multi-level channels and magnetic response functions cannot be formed, and the adsorption capacity and separation efficiency are significantly lower than those of this invention, proving that a single pore-forming agent cannot achieve high performance.

[0074] Please see Figure 1-12 The present invention provides a comparative example 2 (magnetic particles omitted, zeolite retained, traditional activation process).

[0075] Raw material composition (parts by weight): lignin fiber 40, bamboo fiber 20, chitosan 5, sodium bicarbonate 5, attapulgite 5, zeolite 5 (no Fe3O4 nanoparticles)

[0076] Production process

[0077] S1: Same as Comparative Example 1, except that it is soaked in 5% NaOH at 50℃ for 2 hours and dried at 80℃.

[0078] S2: Add the pretreated fiber, 5kg chitosan, 5kg sodium bicarbonate, 5kg attapulgite, and 5kg clinoptilolite (200 mesh, silica-alumina ratio 5) to a mixer and stir for 5 minutes (no ultrasonic dispersion, no magnetic particles). Add water to 50% humidity and granulate into 2mm particles using a traditional granulator (without freeze drying).

[0079] S3 is the same as Comparative Example 1, except that it is 300℃ and nitrogen protection for 1 hour.

[0080] S4: Same as Comparative Example 1, except that it is activated with KOH at 600℃ for 2 hours;

[0081] S5: Same as Comparative Example 1, except that it is dried at 80℃ for 6 hours;

[0082] Although zeolite was added, no magnetic particles were introduced, and traditional centrifugal separation was still relied upon. Furthermore, due to the lack of catalytic activation and freeze-drying, the improvement in porosity and specific surface area was limited, indicating that simply improving the raw material composition does not necessarily lead to a technological breakthrough.

[0083] Please see Figure 1-12 The present invention provides a comparative example 3 (zeolite omitted, magnetic particles retained, traditional activation process).

[0084] Raw material composition (parts by weight): lignin fiber 40, bamboo fiber 20, chitosan 5, sodium bicarbonate 5, attapulgite 5, Fe3O4 nanoparticles 2 (no zeolite)

[0085] Production process

[0086] S1: Same as Comparative Example 1, except that it is soaked in 5% NaOH at 50℃ for 2 hours and dried at 80℃.

[0087] S2: Add the pretreated fiber, 5kg chitosan, 5kg sodium bicarbonate, 5kg attapulgite, and 2kg Fe3O4 nanoparticles (10nm) to a mixer and stir for 5 minutes (without ultrasonic dispersion or zeolite). Add water to 50% humidity and granulate into 2mm particles using a conventional granulator (without freeze drying).

[0088] S3: Same as Comparative Example 1, except that it is 300℃ and nitrogen protection for 1 hour;

[0089] S4: Same as Comparative Example 1, except that it is activated with KOH at 600℃ for 2 hours;

[0090] S5: Same as Comparative Example 1, except that it is dried at 80℃ for 6 hours;

[0091] Although magnetic particles were added, the lack of zeolite ion exchange resulted in a small increase in adsorption capacity. Furthermore, the magnetic particles agglomerated due to the absence of ultrasonic dispersion and freeze granulation, leading to low magnetic response efficiency. This demonstrates that functional fillers need to be synergistic with the process to function effectively.

[0092] Please see Figure 4 The gradient adjustment of the raw material ratio shows a progressive effect of "skeleton strengthening → pore optimization → functional group enrichment". Example 3 achieves maximum performance by using the upper limit of dosage: porosity 85%, specific surface area 800m² / g, lead ion adsorption capacity 180mg / g, proving that there is a significant synergistic effect among the components, rather than a simple superposition.

[0093] Please see Figure 5 The coupling process of catalytic activation and freeze-drying is the core of the performance breakthrough. In Example 3, by using the upper limit of catalyst dosage (2wt% Pt-Co) and the highest activation temperature (600℃), 85% porosity and 800m² / g specific surface area were achieved, which are 6.25% and 33.3% higher than those in Example 1, respectively. This proves that "low-temperature catalytic etching + ice crystal template pore formation" can precisely control the pore size distribution (10-30nm pore volume ratio is stable at 85%), solving the problem of disordered pore size in traditional processes.

[0094] Please see Figure 1-12 Example 1 vs. Comparative Example 1:

[0095] By freeze-drying (ice crystal template) and introducing Fe3O4, the porosity was increased from 68% to 80%, and magnetic response function (32 emu / g) was imparted, solving the core pain points of traditional adsorbents such as "low adsorption efficiency and difficult separation".

[0096] The addition of zeolite increased the proportion of 10-30nm pore size from 60% to 85%, and the phenol adsorption capacity from 40mg / g to 80mg / g, demonstrating the selective adsorption advantage of hierarchical channels for organic matter.

[0097] Please see Figure 1-12 Example 2 vs. Example 1:

[0098] Medium-temperature activation (550℃) and optimization of catalyst dosage (1wt% Pt-Co) achieved a balance between energy consumption and performance, increasing the specific surface area to 700m² / g and the lead ion adsorption capacity to 168mg / g, which is 10.5% higher than that of Example 1, demonstrating the amplification effect of precise control of process parameters on performance.

[0099] The synergistic effect of chitosan and zeolite (silicon-to-aluminum ratio of 8) increases the ion exchange rate by 30% and shortens the adsorption equilibrium time from 60 minutes to 40 minutes, making it suitable for continuous industrial processing.

[0100] Please see Figure 1-12 Example 3:

[0101] The extreme combination of raw materials and process parameters (60 parts lignin fiber, 5 parts Fe3O4, activation at 600℃) achieved a lead ion adsorption capacity of 180 mg / g (2.25 times that of Comparative Example 1) and a saturation magnetization of 50 emu / g (industrial grade standard), becoming the performance benchmark for similar materials;

[0102] With 85% porosity and 800m² / g specific surface area, the material's adsorption capacity for small molecule pollutants such as formaldehyde and toluene is increased to 120mg / g, covering more industrial wastewater treatment scenarios.

[0103] The hierarchical pore structure (85% pore size of 10-30nm) enables highly efficient adsorption of heavy metal ions (such as Pb²⁺) and organic pollutants (such as phenol), with an adsorption capacity 50%-100% higher than that of a single packing system.

[0104] The high-density functional groups (-NH2, -OH) on the surface provide chemical adsorption sites, which improves the adsorption selectivity by 30% compared with traditional physical adsorption materials (such as activated carbon), making it particularly suitable for the removal of target pollutants in complex water quality.

[0105] The magnetic response function (saturation magnetization ≥30 emu / g) enables rapid solid-liquid separation within 30 seconds, which is 30 times more efficient than traditional methods such as centrifugation and filtration, and significantly reduces separation energy consumption and equipment investment.

[0106] In-situ co-precipitation + ultrasonic dispersion process ensures uniform loading of magnetic particles, avoids the decrease in separation efficiency caused by agglomeration (comparative example 3, separation time extended to 40 seconds), and ensures stability for industrial applications;

[0107] The raw materials are all renewable natural materials (lignin, bamboo fiber, chitosan), which reduces the cost by 25% compared to synthetic adsorbents, and the production process has no harmful emissions (it only needs to be washed until neutral).

[0108] The catalytic activation temperature is reduced by 200℃, and combined with freeze-drying, the overall energy consumption is reduced by 30% compared to traditional high-temperature activation processes, meeting the requirements of green manufacturing. The above descriptions are merely embodiments of the present invention; well-known technical solutions or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A porous lignin fiber adsorbent material comprising, characterized by: The raw materials include lignin fiber 40-60 parts by weight, bamboo fiber 20-30 parts by weight, chitosan 5-15 parts by weight, sodium bicarbonate 5-10 parts by weight, attapulgite 5-10 parts by weight, zeolite 5-10 parts by weight, and magnetic nanoparticles 2-5 parts by weight. The porosity of the porous lignin fiber adsorption material is 80-85%, the specific surface area is 600-800 m² / g, the average pore size is 10-30 nm, the adsorption capacity for lead ions is ≥150 mg / g, and the saturation magnetization is ≥30 emu / g. The method comprises the following steps: S1: lignin fiber and bamboo fiber are respectively soaked in a 5-10% sodium hydroxide solution at 50-70°C for 2-4 hours, washed to neutral and dried, to obtain pretreated lignin fiber and pretreated bamboo fiber; S2: the pretreated lignin fiber, bamboo fiber, chitosan, sodium bicarbonate, attapulgite, zeolite and magnetic nanoparticles are added to a blender and dispersed for 10 minutes under 200W ultrasonic conditions to obtain a mixture; S3: deionized water is added to the mixture to a humidity of 50-60%, and the mixture is granulated and freeze-dried at -50°C and 10Pa for 24 hours to obtain precursor particles with a particle size of 2-5mm; S4: the precursor particles are heated to 300-400°C at a rate of 5-10°C / min under nitrogen protection, and held for 1-2 hours to obtain a carbonized product; S5: the carbonized product is mixed with a Pt-Co single-atom catalyst at a mass ratio of 100:1-3, heated to 500-600°C at a rate of 10-15°C / min in a water vapor atmosphere, the water vapor atmosphere flow rate is 0.5-1.5L / min, and the activation is performed for 2-3 hours to obtain activated particles; S6: the activated particles are washed to neutral and dried at 80-100°C for 6-8 hours to obtain the target product.

2. The porous lignin fiber adsorbent material of claim 1, wherein: The magnetic nanoparticles are Fe3O4 nanoparticles with a particle size of 10-30 nm.

3. The porous lignin fiber adsorbent material of claim 1, wherein: The zeolite is clinoptilolite with a particle size of 200-500 mesh and a silicon-aluminum ratio SiO2 / Al2O3 of 5-10.

4. The porous lignin fiber adsorbent material of claim 1, wherein: The degree of deacetylation of the chitosan is 80-95%.

5. The porous lignin fiber adsorbent material of claim 1, wherein: The Pt-Co single-atom catalyst in S5 has a Pt loading of 0.5-2wt% and a Co loading of 1-3wt%, and the catalyst uses activated carbon as a carrier.

6. The porous lignin fiber adsorbent material of claim 1, wherein: The gas in S4 is nitrogen, and the gas flow rate is 1-2L / min.

7. The porous lignin fiber adsorbent material of claim 1, wherein: The magnetic nanoparticles in S2 are prepared by in-situ co-precipitation method, including: dissolving Fe 2+ and Fe 3+ in deionized water at a molar ratio of 1:2, adding ammonia water dropwise at 70-80°C and pH=10 until the precipitation is complete, centrifugal washing and drying to obtain Fe3O4 nanoparticles.

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