An impregnated amine-modified solid amine sorbent and method of making the same

Abstract

The application belongs to the technical field of solid amine adsorbent preparation, and particularly relates to an impregnation method amine modified solid amine adsorbent and a preparation method thereof. By taking fly ash as raw material, acid activated SiO2 precursor is obtained through calcination and acid etching, then the precursor is dissolved by chelating resin exchange alkali solution, and then macroporous directing agent is added to obtain hierarchical porous SiO2, and then combined with polyvinyl alcohol to prepare spherical precursor, and then combined with p-phenylenediamine, 1,3,5-triaminobenzene and the like to form a low-temperature nucleus, and then treated in an inert atmosphere to obtain a composite spherical carrier, and finally the carrier is immersed in an impregnation solution, and then solidified through ultrasonic impregnation and staged heating to obtain the solid amine adsorbent, which has excellent CO2 adsorption performance and strong stability, and the raw material is widely sourced and low in price, and the solid waste is recycled.

Description

Technical Field

[0001] This invention belongs to the field of solid amine adsorbent preparation technology, and specifically relates to an impregnation method for amine-modified solid amine adsorbent and its preparation method. Background Technology

[0002] Carbon capture technologies can be categorized by separation principle into chemical adsorption, physical adsorption, membrane separation, and cryogenic distillation. Among these, chemical absorption / adsorption technology based on amine materials has become one of the most mature technologies in industrial applications due to its advantages such as high selectivity for carbon dioxide and large adsorption capacity. Traditional liquid amine absorption methods suffer from problems such as easy oxidation and degradation of amines, limiting their wider application. In contrast, solid amine adsorption technology, by loading amine functional groups onto the surface and pores of porous carrier materials, combines the high selectivity of chemical absorption with the low regeneration energy consumption of physical adsorption, making it a carbon capture technology with great development potential. Solid amine adsorbents are mainly divided into impregnated solid amine adsorbents, grafted solid amine adsorbents, and in-situ polymerized solid amine adsorbents. Impregnated solid amine adsorbents are produced by physically impregnating amine compounds onto the pores and surface of a porous carrier. Capillary action, surface tension, and hydrogen bonding allow the amine solution to permeate and adsorb into the carrier. After drying to remove the solvent, a stable solid adsorbent material is formed. Depending on the impregnation process, it can be further divided into solution impregnation, vapor deposition and plasma-enhanced impregnation. Among them, solution impregnation is the most widely used preparation method due to its simple process, flexible operation and low cost.

[0003] Chinese Patent CN112403441B discloses a method for preparing a CO2 solid adsorbent supported on chemical bonds with organic amines. Using mesoporous silica (MPS) as a carrier, the method involves carboxyl activation, carrier surface modification, chemical bond reaction immobilization, and solid adsorbent preparation. This effectively solves the problems of low stability and easy decomposition at high temperatures in organic amine-supported CO2 adsorbents, increasing the cycle stability and adsorption rate of the CO2 adsorbent. Chinese Patent CN113877539B discloses a CO2 solid adsorbent and its preparation and application. The method involves dissolving an organic amine in water to obtain solution A, then adding a metal salt to obtain solution B. A porous carrier is then immersed in solution B, and the aqueous solution is evaporated after immersion to obtain the CO2 solid adsorbent. By preparing a lower viscosity organic amine solution, the interaction forces between organic amine molecules are reduced, resulting in high dispersion of the organic amine in the carrier pores. This facilitates the diffusion of CO2 molecules during adsorption, enhances transport, and improves the kinetic adsorption rate.

[0004] Although impregnated solid amine adsorbents have the advantage of simple preparation process, they have shortcomings in terms of cycle stability and adaptability to complex working conditions. Therefore, developing impregnated solid amine adsorbents that can solve the above technical bottlenecks has important application value. Summary of the Invention

[0005] To address at least one of the above problems, the present invention provides a method for preparing an impregnated amine-modified solid amine adsorbent, comprising the following steps:

[0006] S100: Using raw materials including fly ash, after calcination, acid etching, washing and drying, an acid-activated SiO2 precursor is obtained. Then, after chelation resin exchange, washing and drying, alkaline solution etching, macroporous guiding agent is added, reaction, filtration and washing until neutral, and drying to obtain hierarchical pore SiO2.

[0007] S200: Using raw materials including hierarchical SiO2, polyvinyl alcohol, and water, a SiO2 spherical precursor is prepared; using raw materials including the SiO2 spherical precursor, terephthalaldehyde, 1,3,5-triaminobenzene, boric acid, crystallization promoter, and catalyst, a low-temperature reaction nucleation is carried out, followed by heat treatment under an inert atmosphere and vacuum drying to obtain a composite spherical carrier.

[0008] S300 is prepared using hexadecyltrimethylammonium bromide, diethylenetriaminepentaacetic acid, tetraethylenepentamine, ethylene glycol diglycidyl ether, and ethylene glycol aqueous solution as raw materials to obtain the impregnation solution.

[0009] S400. The composite spherical carrier is immersed in the impregnation liquid, ultrasonically impregnated, then cured by segmented heating, washed and dried to obtain the solid amine adsorbent.

[0010] Furthermore, step S100 specifically includes:

[0011] S110. After crushing the fly ash, calcine it at 500-600℃ for 2-3 hours, add nitric acid solution, stir at room temperature for 4-5 hours, filter and wash until neutral, and dry to obtain acid-activated SiO2 precursor.

[0012] S120. Add the acid-activated SiO2 precursor to the chelating resin column, pass deionized water through it for ion exchange, and after the exchange is completed, wash the resin with hydrochloric acid, and then wash and dry it to obtain a clean SiO2 precursor.

[0013] S130. Mix the clean SiO2 precursor with sodium hydroxide solution and stir at 60-80℃ for 3-5 hours. Then add macroporous guiding agent. After the reaction is complete, filter and wash until neutral. After drying, hierarchical porous SiO2 is obtained.

[0014] Furthermore, the fly ash is pulverized to a particle size ≤100μm.

[0015] Furthermore, step S200 specifically includes:

[0016] S210. SiO2 with hierarchical holes, polyvinyl alcohol and water are mixed into a paste, extruded and rolled into spherical particles, and dried to obtain SiO2 spherical precursor.

[0017] S220: Disperse SiO2 spherical precursor, terephthalaldehyde, and 1,3,5-triaminobenzene in ethanol solvent, sonicate until uniformly dispersed, add catalyst, boric acid and crystallization promoter, first react at 50-60℃ for 8-10h, then raise the temperature to 70-90℃ and continue the reaction for 16-18h to obtain composite spherical carrier precursor;

[0018] The composite spherical carrier precursor is obtained by vacuum drying after being kept at 250-350℃ for 2-3 hours under an inert atmosphere (S230).

[0019] Further, step S300 is as follows: hexadecyltrimethylammonium bromide and diethylenetriaminepentaacetic acid are added to an aqueous ethylene glycol solution and stirred until completely dissolved. Tetraethylenepentamine is added and ultrasonically dispersed until uniform. Then, ethylene glycol diglycidyl ether is added and ultrasonically dispersed again to obtain an impregnation solution.

[0020] Furthermore, the ethylene glycol aqueous solution is prepared by mixing ethylene glycol and water at a volume ratio of 2-6:1.

[0021] Further, step S400 specifically includes: immersing the composite spherical carrier in the impregnation solution, ultrasonically impregnating it at 40-45℃ for 2-3 hours, drying it at 50-60℃ for 8-10 hours, then heating it to 130-140℃ and holding it for 3-4 hours, and then washing and drying it to obtain the solid amine adsorbent.

[0022] An impregnation-modified solid amine adsorbent is prepared using the impregnation-modified solid amine adsorbent preparation method described in any of the above technical solutions.

[0023] The present invention has the following beneficial effects:

[0024] This invention uses fly ash as a raw material to prepare a hierarchical porous SiO2 substrate. The raw material is widely available and inexpensive, achieving resource utilization of solid waste and reducing environmental pollution. The hierarchical porous SiO2 structure provides a foundation for subsequent amine loading. The polymer layer of the composite spherical carrier enhances the stability of the amine loading, and segmented temperature curing ensures the stable formation of the amine functional layer, guaranteeing the overall performance of the adsorbent. The entire process is highly operable and easy for industrial-scale production. Detailed Implementation

[0025] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0026] With the acceleration of industrialization, the large-scale combustion of fossil fuels has led to a continuous rise in the concentration of greenhouse gases such as CO2 in the atmosphere, making CO2 capture and storage a global focus. Currently, the preparation of solid amine adsorbents mostly uses pure silicon sources as substrates, resulting in high costs and uneven amine loading, making it difficult to meet the adsorption performance requirements of practical applications. Therefore, this invention provides a method for preparing an impregnated amine-modified solid amine adsorbent, comprising the following steps:

[0027] S100: Using raw materials including fly ash, after calcination, acid etching, washing and drying, an acid-activated SiO2 precursor is obtained. Then, after chelation resin exchange, washing and drying, alkaline solution etching, macroporous guiding agent is added, reaction, filtration and washing until neutral, and drying to obtain hierarchical pore SiO2.

[0028] S200: Using raw materials including hierarchical SiO2, polyvinyl alcohol, and water, a SiO2 spherical precursor is prepared; using raw materials including the SiO2 spherical precursor, terephthalaldehyde, 1,3,5-triaminobenzene, boric acid, crystallization promoter, and catalyst, a low-temperature reaction nucleation is carried out, followed by heat treatment under an inert atmosphere and vacuum drying to obtain a composite spherical carrier.

[0029] S300 is prepared using hexadecyltrimethylammonium bromide, diethylenetriaminepentaacetic acid, tetraethylenepentamine, ethylene glycol diglycidyl ether, and ethylene glycol aqueous solution as raw materials to obtain the impregnation solution.

[0030] S400. The composite spherical carrier is immersed in the impregnation liquid, ultrasonically impregnated, then cured by segmented heating, washed and dried to obtain the solid amine adsorbent.

[0031] In step S100, the chelating resin is preferably an aminophosphonic acid type chelating resin, and the macroporous guiding agent is preferably polyethylene glycol 2000, with an amount of 5-10% of the fly ash mass. In step S200, the mass ratio of hierarchical pore SiO2, polyvinyl alcohol, and water is 100:15-22:65-85; the mass ratio of SiO2 spherical precursor, terephthalaldehyde, 1,3,5-triaminobenzene, boric acid, crystallization promoter, and catalyst is 100:18-25:12-20:6-10:3-5:2-4. In step S300, the ethylene glycol aqueous solution is prepared by mixing ethylene glycol and water at a volume ratio of 2-6:1, preferably 4:1; the mass ratio of hexadecyltrimethylammonium bromide, diethylenetriaminepentaacetic acid, tetraethylenepentamine, ethylene glycol diglycidyl ether, and the ethylene glycol aqueous solution is 2-5:3-6:12-18:6.5-10:80-100. In step S400, the solid-liquid ratio (g:mL) of the composite spherical carrier to the impregnation solution is 1:8-12.

[0032] Specifically, step S100 includes:

[0033] S110. After crushing fly ash, calcine it in air at 500-600℃ for 2-3 hours, add nitric acid solution, stir at room temperature for 4-5 hours, filter, wash with deionized water until neutral, and dry to obtain acid-activated SiO2 precursor.

[0034] S120. Add the acid-activated SiO2 precursor to the chelating resin column, pass deionized water through it for ion exchange, after the exchange is completed, wash the resin with hydrochloric acid, then wash with deionized water until the pH of the washing solution is neutral, and then dry to obtain a clean SiO2 precursor.

[0035] S130. Mix the clean SiO2 precursor with sodium hydroxide solution and stir at 60-80℃ for 3-5 hours. Then add macroporous guiding agent and continue stirring for 1-2 hours. After the reaction is complete, filter, wash with deionized water until neutral, and dry to obtain hierarchical porous SiO2.

[0036] In step S110, fly ash (from Tianjin Petrochemical Thermal Power Plant, mainly rich in silicon and aluminum, with SiO2 content of 48.62 wt.% and Al2O3 content of 40.01 wt.%) is pulverized to a particle size ≤100 μm; the concentration of nitric acid solution is 1-2 mol / L, the solid-liquid ratio (g:mL) of fly ash to nitric acid solution is 1:3-5, and the drying conditions are: drying at 100-110℃ for 6-8 h. In step S120, the deionized water flow rate during ion exchange is 6-10 mL / min, the concentration of hydrochloric acid used for elution is 0.5-1 mol / L, the elution rate is 1-2 mL / min, the elution time is 1-2 h, and the drying conditions are: drying at 100-110℃ for 4-6 h. In step 130, the concentration of sodium hydroxide solution is 2-3 mol / L, the solid-liquid ratio (g:mL) of clean SiO2 precursor to sodium hydroxide solution is 1:2-4, and the drying conditions are: drying at 110-120℃ for 8-10 h.

[0037] In the above steps, calcination of fly ash removes organic impurities and volatile substances, while also creating microcracks within the fly ash particles, which facilitates subsequent penetration and etching with nitric acid. Nitric acid reacts with metal oxides in the fly ash, and the resulting nitrates are removed through filtration and washing, simultaneously etching the SiO2 framework to form a preliminary porous structure. Further, acid-activated SiO2...

[0038] The precursor is added to a chelating resin column, preferably an aminophosphonic acid chelating resin (Purolite aminophosphonic acid chelating cation exchange resin S940, Shanghai Kaiping Resin Co., Ltd.). This resin can chelate with residual metal ions on the surface of the SiO2 precursor to form stable chelates, thereby purifying the SiO2 precursor. The metal ions on the resin are then eluted with hydrochloric acid, and after washing and drying, a clean SiO2 precursor is obtained. Finally, the clean SiO2 precursor is mixed with a sodium hydroxide solution. Sodium hydroxide selectively dissolves the SiO2 framework, forming a mesoporous structure. The added macroporous guiding agent, polyethylene glycol 2000, acts as a template during the etching process, guiding the pores to grow towards macropores, ultimately forming a hierarchical porous SiO2 with both mesopores and macropores. This hierarchical porous structure increases the subsequent amine loading and gas diffusion rate.

[0039] Specifically, step S200 includes:

[0040] S210. SiO2 with hierarchical holes, polyvinyl alcohol and water are mixed into a paste, extruded and rolled into spherical particles, and dried to obtain SiO2 spherical precursor.

[0041] S220: Disperse SiO2 spherical precursor, terephthalaldehyde, and 1,3,5-triaminobenzene in 95% ethanol solvent, sonicate until uniformly dispersed, add catalyst, boric acid and crystallization promoter, first stir at 50-60℃ for 8-10h, then raise the temperature to 70-90℃ and continue stirring for 16-18h to obtain composite spherical carrier precursor;

[0042] The composite spherical carrier precursor is obtained by vacuum drying after being kept at 250-350℃ for 2-3 hours under an inert atmosphere (S230).

[0043] In step S210, the mixing temperature is 60-70℃, the stirring time is 1-2 hours, and a uniform paste is prepared. The extrusion speed of the extrusion and spheroidizing equipment is 50-60 r / min, the spheroidizing speed is 200-300 r / min, and the spheroidizing time is 10-15 minutes. The prepared spherical particles have a particle size of 0.5-1.0 mm. The drying conditions are: drying at 90-100℃ for 8-10 hours. In step S220, the catalyst is hydrochloric acid, and the crystallization promoter is sodium acetate. The ultrasonic conditions are: power 100-150 W, ultrasonic time 20-40 minutes. In step S230, the vacuum drying conditions are: drying at 100-110℃ for 6-8 hours.

[0044] In the above steps, firstly, hierarchical SiO2, polyvinyl alcohol (degree of polymerization 1700-1800) and water are mixed. Polyvinyl alcohol acts as a binder, and its molecular chains can interact with the hydroxyl groups on the surface of hierarchical SiO2 through hydrogen bonds, thus bonding the SiO2 particles together to form a uniform paste material, thereby preparing the SiO2 spherical precursor. Subsequently, the SiO2 spherical precursor, terephthalaldehyde, and 1,3,5-triaminobenzene were dispersed in an ethanol solvent. After uniform ultrasonic dispersion, hydrochloric acid, boric acid, and sodium acetate as a crystallization promoter were added. The aldehyde groups in terephthalaldehyde and the amino groups in 1,3,5-triaminobenzene underwent a Schiff base reaction at 50-60°C to generate a polymer containing imine bonds. Boric acid, as a crosslinking agent, enhanced the bonding force between the polymer and the SiO2 spherical precursor substrate. Sodium acetate, as a crystallization promoter, guided polymer crystallization and improved the structural stability of the carrier. Further increasing the temperature could make the reaction more complete, ultimately forming a polymer layer uniformly coated on the surface of the SiO2 spherical precursor, thus obtaining a composite spherical carrier precursor. Finally, under an inert atmosphere (preferably a nitrogen atmosphere), high-temperature holding could remove residual solvents and small molecule impurities from the carrier, while simultaneously causing the polymer layer to undergo slight crosslinking and curing, improving the thermal stability and mechanical strength of the carrier.

[0045] Step S300 involves adding hexadecyltrimethylammonium bromide and diethylenetriaminepentaacetic acid to an aqueous ethylene glycol solution, stirring at 50-60°C for 30-40 minutes until completely dissolved, adding tetraethylenepentamine, ultrasonically dispersing for 20-30 minutes, then adding ethylene glycol diglycidyl ether, and continuing ultrasonically dispersing for another 20-30 minutes to obtain the impregnation solution.

[0046] In this step, ethylene glycol aqueous solution, as a solvent, exhibits good solubility and dispersibility. Hexadecyltrimethylammonium bromide, as a surfactant, reduces the surface tension of the solution, improving the adsorption performance of the amine component on the composite spherical carrier surface. Diethylenetriaminepentaacetic acid, as a chelating agent, can chelate with trace metal ions present in the solution, preventing the metal ions from adversely affecting the amine loading and adsorption performance. Tetraethylenepentamine is the main active amine component; ultrasonic dispersion ensures uniform dispersion of tetraethylenepentamine in the solution, preventing excessively high local concentrations that could lead to amine component aggregation. The epoxy groups in ethylene glycol diglycidyl ether can undergo ring-opening reactions with the amino groups in tetraethylenepentamine to form cross-linked amine polymer precursors. These precursors can be firmly loaded onto the composite spherical carrier surface during subsequent curing, preventing the loss of the amine component.

[0047] Specifically, step S400 includes: immersing the composite spherical carrier in an impregnation solution, ultrasonically impregnating it at 40-45℃ for 2-3 hours, drying it at 50-60℃ for 8-10 hours, then heating it to 130-140℃ and holding it at that temperature for 3-4 hours in an inert gas atmosphere, preferably nitrogen. After holding it at that temperature, cooling it to room temperature, washing it with deionized water until the pH of the washing solution is neutral, and then drying it at 80-90℃ for 4-6 hours to obtain the solid amine adsorbent.

[0048] In this step, the composite spherical carrier is immersed in an impregnation solution. Ultrasonic vibration allows the impregnation solution to rapidly penetrate the hierarchical channels of the composite spherical carrier. Simultaneously, the hydroxyl groups on the carrier surface and the imine bonds in the polymer layer interact with the amine polymer precursor, causing the amine component to be initially adsorbed on the carrier surface and within the channels. Finally, drying at 50-60℃ removes the solvent from the impregnation solution, allowing the amine polymer precursor to form a thin film on the carrier surface. Further heating to 130-140℃ allows for further cross-linking and curing of the amine polymer precursor, forming a stable amine functional layer, ultimately yielding a solid amine adsorbent with high amine loading and strong stability. The segmented heating and curing process allows for solvent removal during low-temperature drying, avoiding the volatilization of the amine component caused by direct high-temperature drying; high-temperature holding ensures complete curing of the amine polymer precursor, guaranteeing a strong bond between the amine functional layer and the carrier, and ensuring the overall performance of the adsorbent.

[0049] Example 1

[0050] A method for preparing an impregnated amine-modified solid amine adsorbent includes the following steps:

[0051] S1. Take 150g of pulverized fly ash, calcine it in air at 550℃ for 2.5h, cool it to room temperature, add 450mL of 1.5mol / L nitric acid solution, stir at room temperature for 4.5h, filter, wash with deionized water until the pH of the washing solution is neutral, and dry at 110℃ for 7h to obtain acid-activated SiO2 precursor.

[0052] S2. 102.3g of acid-activated SiO2 precursor was passed into a chelating resin column (2.5cm in diameter, 55cm in height, filled with 250mL of aminophosphonic acid chelating resin), while deionized water was passed through at a flow rate of 7mL / min for ion exchange for 2.5h. Then, 250mL of 0.8mol / L hydrochloric acid solution was passed through at a rate of 1.5mL / min to elute the resin for 1.5h. After elution, the solution was washed with deionized water until the pH of the washing solution was neutral, and then dried at 110℃ for 5h to obtain a clean SiO2 precursor.

[0053] S3. Mix 98.5g of clean SiO2 precursor with 300mL of 2.5mol / L sodium hydroxide solution, stir at 70℃ for 4h, then add 10.5g of macroporous guiding agent polyethylene glycol 2000, continue stirring for 1.5h, filter, wash with deionized water until the pH of the washing solution is neutral, and dry at 120℃ for 9h to obtain hierarchical porous SiO2.

[0054] S4. Mix 100g of hierarchical SiO2, 20g of polyvinyl alcohol and 82g of deionized water and stir at 65℃ for 1.5h to prepare a uniform paste; add the paste to an extrusion spheroidizer (extrusion speed 55r / min, spheroidizing speed 250r / min, spheroidizing time 12min) to prepare spherical particles with a particle size of 0.5-1.0mm, and dry at 100℃ for 9h to obtain SiO2 spherical precursor;

[0055] S5. 100g of SiO2 spherical precursor, 20g of terephthalaldehyde, and 15g of 1,3,5-triaminobenzene were dispersed in 200mL of 95% ethanol solvent and ultrasonically dispersed at 120W for 30min. Then, 3g of 30% hydrochloric acid, 7g of boric acid, and 4g of sodium acetate crystallization promoter were added. The mixture was stirred at 55℃ for 9h, and then the temperature was increased to 80℃ and the mixture was stirred for 17h to obtain a composite spherical carrier precursor. The precursor was placed in a nitrogen atmosphere and kept at 300℃ for 2.5h. After cooling, it was placed in a vacuum drying oven at 110℃ and vacuum dried for 7h to obtain the composite spherical carrier.

[0056] S6. Mix 120 mL of ethylene glycol and 30 mL of deionized water, then add 3.5 g of cetyltrimethylammonium bromide and 4.5 g of diethylenetriaminepentaacetic acid. Stir at 55 °C for 35 min, then add 15 mL of tetraethylenepentamine. After ultrasonic dispersion for 25 min, add 7.5 mL of ethylene glycol diglycidyl ether and continue ultrasonic dispersion for 25 min to obtain the impregnation solution.

[0057] S7. Immerse 100g of composite spherical carrier in 700mL of impregnation solution, use a constant temperature water bath at 42℃, ultrasonically impregnate for 2.5h, dry at 55℃ for 9h, then heat to 135℃ at a heating rate of 2.5℃ / min, purge with nitrogen and keep warm for 3.5h, cool to room temperature, wash with deionized water until the pH of the washing solution is neutral, and then dry at 85℃ for 5h to obtain solid amine adsorbent.

[0058] Example 2

[0059] This embodiment differs from Embodiment 1 in the following ways:

[0060] In step S1, 100g of pulverized fly ash was calcined in air at 500℃ for 3h and then cooled to room temperature. 300mL of 1mol / L nitric acid solution was added, and the mixture was stirred at room temperature for 5h. After filtration, the mixture was washed with deionized water until the pH of the washing solution was neutral. The mixture was then dried at 100℃ for 8h to obtain the acid-activated SiO2 precursor.

[0061] In step S2, 68.5 g of acid-activated SiO2 precursor was passed into a chelating resin column (filled with 200 mL of aminophosphonic acid chelating resin), and deionized water was passed through at a flow rate of 6 mL / min for ion exchange for 3 h. Then, 200 mL of 0.5 mol / L hydrochloric acid solution was passed through at a rate of 1 mL / min for 2 h to wash until the pH of the washing solution was neutral. After drying at 100 °C for 6 h, a clean SiO2 precursor was obtained.

[0062] In step S3, 65.2g of clean SiO2 precursor was mixed with 200mL of 2mol / L sodium hydroxide solution and stirred at 60℃ for 5h. Then, 5g of macroporous guiding agent polyethylene glycol 2000 was added and stirred for another 2h. After filtration, the mixture was washed until the pH of the washing solution was neutral and dried at 110℃ for 10h to obtain hierarchical porous SiO2.

[0063] In step S4, 100g of hierarchical SiO2, 15g of polyvinyl alcohol and 65g of deionized water are mixed and stirred at 60℃ for 2h; the paste is added to an extrusion spherical mill (extrusion speed of 50r / min, spherical speed of 200r / min, spherical time of 15min) to prepare spherical particles with a particle size of 0.5-1.0mm, which are then dried at 90℃ for 10h to obtain the SiO2 spherical precursor.

[0064] In step S5, 100g of SiO2 spherical precursor, 18g of terephthalaldehyde, and 12g of 1,3,5-triaminobenzene were dispersed in 180mL of 95% ethanol solvent and ultrasonically dispersed at 150W for 40min. Then, 2g of 30% hydrochloric acid, 6g of boric acid, and 3g of sodium acetate crystallization promoter were added, and the mixture was stirred at 50℃ for 10h. Subsequently, the temperature was increased to 70℃ and the mixture was stirred for another 18h to obtain the composite spherical carrier precursor. The precursor was placed under a nitrogen atmosphere and kept at 250℃ for 3h. After cooling, it was placed in a vacuum drying oven at 100℃ and vacuum dried for 8h to obtain the composite spherical carrier.

[0065] In step S6, 80 mL of ethylene glycol and 20 mL of deionized water are mixed, and then 2 g of cetyltrimethylammonium bromide and 3 g of diethylenetriaminepentaacetic acid are added. The mixture is stirred at 50 °C for 40 min, and then 12 mL of tetraethylenepentamine is added. After ultrasonic dispersion for 30 min, 67.5 mL of ethylene glycol diglycidyl ether is added, and ultrasonic dispersion is continued for another 30 min to obtain the impregnation solution.

[0066] In step S7, 100g of composite spherical carrier is immersed in 800mL of impregnation solution, and then ultrasonically impregnated in a 42℃ constant temperature water bath for 3h. After that, it is dried at 50℃ for 10h, then heated to 130℃, kept at nitrogen protection for 4h, and then cooled to room temperature. The washing solution is washed until the pH is neutral, and then dried at 80℃ for 6h to obtain solid amine adsorbent.

[0067] Example 3

[0068] This embodiment differs from Embodiment 1 in the following ways:

[0069] In step S1, 200g of pulverized fly ash was calcined in air at 600℃ for 2h and then cooled to room temperature. 1000mL of 2mol / L nitric acid solution was added, and the mixture was stirred at room temperature for 4h. After filtration, the mixture was washed with deionized water until the pH of the washing solution was neutral. After drying at 110℃ for 6h, acid-activated SiO2 precursor was obtained.

[0070] In step S2, 135.8 g of acid-activated SiO2 precursor was passed into a chelating resin column (filled with 300 mL of aminophosphonic acid chelating resin), and deionized water was passed through at a flow rate of 10 mL / min for ion exchange for 2 h. Then, 300 mL of 1 mol / L hydrochloric acid solution was passed through at a rate of 2 mL / min to elute the resin for 1 h. After elution, the solution was washed with deionized water until the pH of the washing solution was neutral, and then dried at 110 °C for 4 h to obtain a clean SiO2 precursor.

[0071] In step S3, 130.2g of clean SiO2 precursor was mixed with 400mL of 3mol / L sodium hydroxide solution and stirred at 80℃ for 3h. Then, 20g of macroporous guiding agent polyethylene glycol 2000 was added and stirred for another 1h. After filtration, the mixture was washed with deionized water until the pH of the washing solution was neutral and dried at 120℃ for 8h to obtain hierarchical porous SiO2.

[0072] In step S4, 100g of hierarchical SiO2, 22g of polyvinyl alcohol and 85g of deionized water are mixed and stirred at 70℃ for 1h to prepare a uniform paste. The paste is added to an extrusion spheroidizer (extrusion speed is 60r / min, spheroidizing speed is 300r / min, spheroidizing time is 10min) to prepare spherical particles with a particle size of 0.5-1.0mm. After drying at 100℃ for 8h, a SiO2 spherical precursor is obtained.

[0073] In step S5, 100g of SiO2 spherical precursor, 25g of terephthalaldehyde, and 20g of 1,3,5-triaminobenzene were dispersed in 250mL of 95% ethanol solvent and ultrasonically dispersed at 200W for 30min. Then, 4g of 30% hydrochloric acid, 10g of boric acid, and 5g of sodium acetate crystallization promoter were added. The mixture was stirred at 60℃ for 8h, and then the temperature was increased to 90℃ and the stirring was continued for 16h to obtain the composite spherical carrier precursor. The precursor was placed under a nitrogen atmosphere and kept at 350℃ for 2h. After cooling, it was placed in a vacuum drying oven at 110℃ for 6h to obtain the composite spherical carrier.

[0074] In step S6, 160 mL of ethylene glycol and 40 mL of deionized water are mixed, and then 5 g of cetyltrimethylammonium bromide and 6 g of diethylenetriaminepentaacetic acid are added. The mixture is stirred at 60 °C for 30 min, and then 18 mL of tetraethylenepentamine is added. After ultrasonic dispersion for 20 min, 10 mL of ethylene glycol diglycidyl ether is added, and ultrasonic dispersion is continued for another 20 min to obtain the impregnation solution.

[0075] In step S7, 100g of composite spherical carrier is immersed in 1200mL of impregnation solution, and ultrasonically impregnated in a 45℃ constant temperature water bath for 2h. After that, it is dried at 60℃ for 8h, and then heated to 140℃ at a heating rate of 3℃ / min. Nitrogen gas is introduced and kept at this temperature for 3h. After cooling to room temperature, it is washed with deionized water until the pH of the washing solution is neutral. Then it is dried at 90℃ for 4h to obtain solid amine adsorbent.

[0076] Example 4

[0077] This embodiment differs from Embodiment 1 in the following ways:

[0078] In step S1, 180g of pulverized fly ash was calcined in air at 580℃ for 2.5h and then cooled to room temperature. 720mL of 1.8mol / L nitric acid solution was added, and the mixture was stirred at room temperature for 4.5h. After filtration, the mixture was washed with deionized water until the pH of the washing solution was neutral. After drying at 108℃ for 6.5h, acid-activated SiO2 precursor was obtained.

[0079] In step S2, 122.5 g of acid-activated SiO2 precursor was passed into a chelating resin column (filled with 280 mL of aminophosphonic acid chelating resin), and deionized water was simultaneously passed through at a flow rate of 9 mL / min for ion exchange for 2.5 h. Subsequently, 280 mL of 0.9 mol / L hydrochloric acid solution was passed through at a rate of 1.8 mL / min to elute the resin for 1.2 h. After elution, the solution was washed with deionized water until the pH of the washing solution was neutral, and then dried at 108 °C for 4.5 h to obtain a clean SiO2 precursor.

[0080] In step S3, 118.3g of clean SiO2 precursor was mixed with 350mL of 2.8mol / L sodium hydroxide solution and stirred at 75℃ for 3.5h. Then, 14.4g of macroporous guiding agent polyethylene glycol 2000 was added and stirred for another 1.2h. After filtration, the mixture was washed with deionized water until the pH of the washing solution was neutral. After drying at 118℃ for 8.5h, hierarchical porous SiO2 was obtained.

[0081] In step S4, 100g of hierarchical SiO2, 20g of polyvinyl alcohol and 75g of deionized water are mixed and stirred at 68℃ for 1.2h to prepare a uniform paste. The paste is added to an extrusion spheroidizer (extrusion speed of 58r / min, spheroidizing speed of 280r / min, spheroidizing time of 11min) to prepare spherical particles with a particle size of 0.5-1.0mm. After drying at 95℃ for 8.5h, a SiO2 spherical precursor is obtained.

[0082] In step S5, 100g of SiO2 spherical precursor, 22g of terephthalaldehyde, and 18g of 1,3,5-triaminobenzene were dispersed in 220mL of 95% ethanol solvent and ultrasonically dispersed at 120W for 40min. Then, 3.5g of 30% hydrochloric acid, 8g of boric acid, and 4.5g of sodium acetate crystallization promoter were added, and the mixture was stirred at 55℃ for 9h. Subsequently, the temperature was increased to 85℃ and the mixture was stirred for another 16h to obtain a composite spherical carrier precursor. This precursor was placed under a nitrogen atmosphere and kept at 320℃ for 2.5h. After cooling, it was placed in a vacuum drying oven at 110℃ and vacuum dried for 6.5h to obtain the composite spherical carrier.

[0083] In step S6, 140 mL of ethylene glycol and 35 mL of deionized water are mixed, and then 4 g of cetyltrimethylammonium bromide and 5 g of diethylenetriaminepentaacetic acid are added. The mixture is stirred at 55 °C for 35 min, and then 16.5 mL of tetraethylenepentamine is added. After ultrasonic dispersion for 25 min, 9 mL of ethylene glycol diglycidyl ether is added, and ultrasonic dispersion is continued for 25 min to obtain the impregnation solution.

[0084] In step S7, 100g of composite spherical carrier is immersed in 1000mL of impregnation solution, and ultrasonically impregnated in a 45℃ constant temperature water bath for 2h. After that, it is dried at 60℃ for 8.5h, and then heated to 140℃ at a heating rate of 2.5℃ / min. Nitrogen gas is introduced and kept at this temperature for 3h. After cooling to room temperature, it is washed with deionized water until the pH of the washing solution is neutral. Then it is dried at 85℃ for 4.5h to obtain solid amine adsorbent.

[0085] Comparative Example 1

[0086] Compared with Example 1, this comparative example does not undergo chelation resin exchange purification, but all other steps are the same as in Example 1, that is, the acid-activated SiO2 precursor is directly etched by alkaline solution (i.e., step S2 is omitted).

[0087] Comparative Example 2

[0088] Compared with Example 1, this comparative example does not add the macroporous guiding agent polyethylene glycol 2000 in the preparation process of step S3, while all other steps are the same as in Example 1.

[0089] Comparative Example 3

[0090] Compared with Example 1, this comparative example directly uses the SiO2 spherical precursor as a carrier for amine impregnation (i.e., step S5 is omitted), while the rest is the same as in Example 1.

[0091] Comparative Example 4

[0092] Compared with Example 1, this comparative example does not include cetyltrimethylammonium bromide and diethylenetriaminepentaacetic acid in step S6, while all other steps are the same as in Example 1.

[0093] Comparative Example 5

[0094] Compared with Example 1, in this comparative example, tetraethylenepentamine was replaced with ethanolamine in step S6, while all other steps were the same as in Example 1.

[0095] Related tests

[0096] 1. The adsorption performance of the solid amine adsorbents prepared in Examples 1 to 4 and Comparative Examples 1 to 5 was tested. After several adsorption-desorption cycles, the changes in carbon dioxide capture were recorded. The test results are shown in Table 1. The method for testing carbon dioxide adsorption was as follows: The CO2 adsorption performance of the prepared solid amine adsorbents was tested using a TGA / DSC simultaneous thermal analyzer. High-purity N2 was introduced into the instrument, and the sample was heated from room temperature to 110°C at a rate of 10°C / min and held at this temperature for 3 hours. Then, the sample was cooled to 25°C at a rate of 10°C / min, and high-purity N2 was introduced at this temperature for 2 hours. The gas flow was then switched to a mixed gas containing 400 ppm CO2 and the remainder being N2, and this was maintained for 12 hours until the solid adsorbent reached saturation. Then, high-purity N2 was introduced again, and the sample was heated from 25°C to 110°C at a rate of 10°C / min for desorption. The multiple-cycle adsorption-desorption process follows the same steps as this process, with each cycle consisting of an adsorption time of 8.5 hours, a desorption time of 35 minutes, and 10 cycles.

[0097] Table 1 Adsorption performance test results

[0098]

[0099] 2. The adsorption capacity of the solid amine adsorbents prepared in each example and comparative example for carbon dioxide was tested by TGA using simulated flue gas (10% CO2, balanced with argon) under dry conditions and at different temperatures. The test results are shown in Table 2.

[0100] Table 2 Adsorption performance test results at different temperatures

[0101]

[0102] Analysis of the test data in Tables 1 and 2 shows that the solid amine adsorbent prepared in Example 1 has the best performance, while Comparative Example 5 has the worst performance. This is because replacing tetraethylenepentamine with ethanolamine results in insufficient binding sites for carbon dioxide, and the monoamine has poor thermal stability, leading to significant loss during cycling. Comparison of the test results between Comparative Example 1 and Example 1 shows that omitting the chelating resin purification step results in a higher impurity content on the carrier, thus causing a decrease in adsorption capacity. In Comparative Example 2, omitting the macroporous directing agent resulted in a carrier with poor pore structure, insufficient adsorption sites, and a decrease in adsorption capacity. Compared to Example 1, Comparative Example 4 (without cetyltrimethylammonium bromide and diethylenetriaminepentaacetic acid) showed a decrease in adsorption capacity because the lack of cetyltrimethylammonium bromide and diethylenetriaminepentaacetic acid caused the amine components to easily aggregate in the impregnation solution, resulting in uneven distribution on the carrier surface after loading, hindering carbon dioxide diffusion, and reducing adsorption performance and cycling stability. Comparative Example 3 (using SiO2 spherical precursors directly as a support for amine impregnation) showed a larger decay rate. This is because the support surface was not coated with polymers, which prevented the support from effectively fixing the amine components, resulting in a reduced amine loading, increased amine loss during cycling, and poorer adsorption stability.

[0103] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0104] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an impregnated amine-modified solid amine sorbent, characterized by, Includes the following steps: S100 uses raw materials including fly ash, which are calcined, acid etched, washed, and dried to obtain an acid-activated SiO2 precursor. This precursor is then subjected to chelating resin exchange, washing, drying, and alkaline solution etching, followed by the addition of a macroporous guiding agent. The reaction is then filtered, washed until neutral, and dried to obtain hierarchical porous SiO2. The amount of macroporous guiding agent used is 5-10% of the fly ash mass. S200: Using raw materials including hierarchical porous SiO2, polyvinyl alcohol, and water, a spherical SiO2 precursor is prepared. Using raw materials including the spherical SiO2 precursor, terephthalaldehyde, 1,3,5-triaminobenzene, boric acid, a crystallization promoter, and a catalyst, the mixture is first reacted at a constant temperature of 50-60℃ for 8-10 hours, then the temperature is increased to 70-90℃ and the reaction continues for 16-18 hours to obtain a composite spherical carrier precursor. Then, under an inert atmosphere... The composite spherical carrier precursor was kept at 250-350℃ for 2-3 hours and then vacuum dried to obtain the composite spherical carrier; wherein the mass ratio of hierarchical pore SiO2, polyvinyl alcohol and water was 100:15-22:65-85; the mass ratio of SiO2 spherical precursor, terephthalaldehyde, 1,3,5-triaminobenzene, boric acid, crystallization promoter and catalyst was 100:18-25:12-20:6-10:3-5:2-4; S300 is prepared using hexadecyltrimethylammonium bromide, diethylenetriaminepentaacetic acid, tetraethylenepentamine, ethylene glycol diglycidyl ether, and an aqueous solution of ethylene glycol as raw materials; wherein the mass ratio of hexadecyltrimethylammonium bromide, diethylenetriaminepentaacetic acid, tetraethylenepentamine, ethylene glycol diglycidyl ether, and aqueous solution of ethylene glycol is 2-5:3-6:12-18:6.5-10:80-100; S400. The composite spherical carrier is immersed in the impregnation solution, ultrasonically impregnated at 40-45℃ for 2-3 hours, dried at 50-60℃ for 8-10 hours, and then heated to 130-140℃ and kept at that temperature for 3-4 hours. After washing and drying, the solid amine adsorbent is obtained. The solid-liquid ratio of the composite spherical carrier to the impregnation liquid is 1g:8-12ml.

2. The method for preparing an impregnated amine-modified solid amine adsorbent according to claim 1, characterized in that, Step S100 specifically includes: S110. After crushing the fly ash, calcine it at 500-600℃ for 2-3 hours, add nitric acid solution, stir at room temperature for 4-5 hours, filter and wash until neutral, and dry to obtain acid-activated SiO2 precursor. S120. Add the acid-activated SiO2 precursor to the chelating resin column, pass deionized water through it for ion exchange, and after the exchange is completed, wash the resin with hydrochloric acid, and then wash and dry it to obtain a clean SiO2 precursor. S130. Mix the clean SiO2 precursor with sodium hydroxide solution and stir at 60-80℃ for 3-5 hours. Then add macroporous guiding agent. After the reaction is complete, filter and wash until neutral. After drying, hierarchical porous SiO2 is obtained.

3. The method of claim 2, wherein the impregnated amine-modified solid amine adsorbent is prepared by the steps of: Fly ash is pulverized to a particle size ≤100μm.

4. The method of claim 1, wherein the impregnated amine-modified solid amine adsorbent is prepared by the steps of: Step S200 specifically includes: S210. SiO2 with hierarchical pores, polyvinyl alcohol and water are mixed into a paste, extruded and rolled into spherical particles, and dried to obtain SiO2 spherical precursor. S220: Disperse SiO2 spherical precursor, terephthalaldehyde, and 1,3,5-triaminobenzene in ethanol solvent, sonicate until uniformly dispersed, add catalyst, boric acid and crystallization promoter, first react at 50-60℃ for 8-10h, then raise the temperature to 70-90℃ and continue the reaction for 16-18h to obtain composite spherical carrier precursor; The composite spherical carrier precursor is obtained by vacuum drying after being kept at 250-350℃ for 2-3 hours under an inert atmosphere (S230).

5. The method for preparing an impregnated amine-modified solid amine adsorbent according to claim 1, characterized in that, Step S300 is as follows: hexadecyltrimethylammonium bromide and diethylenetriaminepentaacetic acid are added to an aqueous ethylene glycol solution and stirred until completely dissolved. Tetraethylenepentamine is added and ultrasonically dispersed until uniform. Then, ethylene glycol diglycidyl ether is added and ultrasonic dispersion is continued to obtain the impregnation solution.

6. The method for preparing an impregnated amine-modified solid amine adsorbent according to claim 5, characterized in that, Ethylene glycol aqueous solution is prepared by mixing ethylene glycol and water at a volume ratio of 2-6:

1.

7. An impregnation-modified solid amine adsorbent, characterized in that, It was prepared using the impregnation method for preparing solid amine adsorbents modified with amines as described in any one of claims 1-6.

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