A method for preparing a biomatrix-mediated hydrophobic calcium-based sorbent of honeycomb structure

Abstract

The application provides a preparation method of a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent, and comprises the following steps: respectively preparing a stabilizer gel, a template solution and a precursor mixed solution containing a calcium source and a manganese source; mixing the template solution and the stabilizer gel to form a supramolecular mixed solution; dropwise adding the supramolecular mixed solution into the precursor mixed solution to form microspheres and soak and age; performing directional freezing treatment on the microspheres, and then performing freeze drying to form honeycomb-shaped channels in the microspheres; calcining the microspheres in an inert atmosphere to form a hydrophobic carbon film, and inducing manganese doping to form oxygen vacancies, so as to obtain the honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent. The application reduces the diffusion resistance of carbon dioxide in the calcium-based adsorbent, makes the calcium-based adsorbent difficult to be coalesced in high-temperature cyclic operation, reduces the interference ability of water molecules, and improves the adsorption performance on carbon dioxide.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide adsorption technology, and in particular to a method for preparing a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent. Background Technology

[0002] Among numerous carbon capture, utilization, and storage technologies, calcium recycling technology stands out as one of the most promising technological pathways due to its significant advantages, including high adsorption heat, wide availability of materials, large theoretical adsorption capacity, and environmental friendliness.

[0003] In the prior art, Chinese patent CN112316887A discloses a method for regulating the microstructure of calcium-based CO2 adsorbents, proposing to use calcium nitrate tetrahydrate and citric acid monohydrate to regulate the microstructure of the adsorbent. Chinese patent CN117732422A discloses calcium-based carbon dioxide adsorbents, their preparation methods, and applications, disclosing an adsorbent using calcium hydroxide, unsaturated organic compounds, and metal oxides as raw materials. Chinese patent CN109954476A discloses a method for preparing manganese-doped double-shell calcium carbonate hollow microsphere CO2 adsorbents, achieving the preparation of manganese-doped double-shell calcium carbonate hollow microsphere CO2 adsorbents by adjusting the calcium-manganese ratio, carbon sphere template, and solvent composition. While the technical solutions of the above patents improve the adsorption performance of carbon dioxide adsorbents to some extent, they have the following drawbacks:

[0004] 1. Limited kinetics and severe capacity decay: The calcium-based adsorbents prepared by the above patents have disordered pore distribution and mostly disordered stacking structures, which leads to extremely high diffusion resistance of gas in the deep layers of the material, thus limiting their initial adsorption capacity.

[0005] 2. High-temperature sintering and lack of thermal stability: Calcium-based materials are prone to grain aggregation at high temperatures, and active sites are rapidly buried in repeated thermal cycles, resulting in the complete loss of activity of calcium-based materials.

[0006] 3. Competitive adsorption in complex flue gas environments: The calcium-based adsorbents prepared by the above patents generally lack the ability to shield water molecules. In humid flue gas, water molecules will strongly compete for active sites and occupy diffusion channels, thereby weakening the selectivity for carbon dioxide. Summary of the Invention

[0007] The present invention aims to provide a method for preparing a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent, so as to reduce the diffusion resistance of carbon dioxide in the calcium-based adsorbent, make it difficult for the calcium-based adsorbent to aggregate during high-temperature cycling, reduce the interference of water molecules, and improve the adsorption performance of carbon dioxide.

[0008] Therefore, the technical solution adopted in this invention is: a method for preparing a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent, comprising the following steps:

[0009] S1. Prepare stabilizer gel, template agent solution and precursor mixture containing calcium source and manganese source respectively;

[0010] S2. The template agent solution is mixed with the stabilizer gel to form a supramolecular mixture with a supramolecular complex structure. The template agent solution is at least one of cyclodextrin solution, microcrystalline cellulose solution, polyethylene solution, and glucose solution. The stabilizer gel is at least one of xanthan gum gel and sodium alginate gel.

[0011] S3. The supramolecular mixture is added to the precursor mixture using coaxial dropping technology to form microspheres through a contact reaction, and the microspheres are then soaked and aged.

[0012] S4. Take out the microspheres and perform directional freezing treatment to guide the controlled growth of ice crystals, thereby squeezing the components for directional rearrangement. Then freeze-dry the microspheres to sublimate the ice crystals in the microspheres and form honeycomb-shaped channels that are distributed in a divergent manner from the center to the surface of the microspheres.

[0013] S5. The microspheres are calcined at high temperature under an inert atmosphere, causing the organic components to undergo in-situ pyrolysis to form a hydrophobic carbon film, and inducing manganese doping to form oxygen vacancies, thereby obtaining a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent. The honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent includes CaO, CaMnO3, and Ca4Mn3O4. 10 .

[0014] As a preferred embodiment of the above scheme, the mass percentage concentration of the stabilizer in the stabilizer gel is 0.8% to 3%. The preferred mass percentage concentration of the stabilizer in the stabilizer gel is 1.5% to 2.5%, and most preferably 2%.

[0015] More preferably, the mass percentage concentration of the template agent in the template agent solution is 0.5% to 3%.

[0016] More preferably, the precursor mixture is formed by mixing a first precursor material and a second precursor material with water. The first precursor material includes a calcium skeletal source and a hydrophobic modifier. The calcium skeletal source is calcium chloride or calcium nitrate, and the hydrophobic modifier is calcium stearate. The second precursor material is manganese nitrate tetrahydrate.

[0017] More preferably, the molar ratio of the first precursor material to the second precursor material, calculated based on the metal elements Ca and Mn, is 100:(3~30), preferably 100:15.

[0018] More preferably, in step S2, the mass ratio of the stabilizer gel to the template agent solution is (1~5):1, preferably 2:1.

[0019] More preferably, in step S3, the volume ratio of the supramolecular mixture to the precursor mixture is 1:(2~10), more preferably 1:(3~6). This preferred ratio ensures the formation of composite microspheres with good sphericity and uniform component distribution during coaxial drop addition.

[0020] More preferably, in step S4, the freeze-drying is ultra-low temperature freeze-drying at a temperature of -60 to -80°C.

[0021] More preferably, in step S5, the inert atmosphere is a nitrogen atmosphere, and the calcination temperature and time are 800~900℃ and 1~2h, respectively, with the calcination temperature preferably being 850℃.

[0022] The beneficial effects of this invention are:

[0023] 1. By performing directional freezing and freeze-drying on the microspheres, the ice crystals in the microspheres sublimate, forming honeycomb-like channels that are distributed divergently from the center to the surface of the microspheres. This greatly shortens the radial diffusion path of carbon dioxide, reduces the diffusion resistance of carbon dioxide, and enables rapid transfer and instantaneous capture of carbon dioxide inside the calcium-based adsorbent of this invention, thereby increasing the initial adsorption capacity.

[0024] 2. By calcining microspheres in an inert atmosphere and inducing oxygen vacancies formed by manganese doping, the honeycomb framework (i.e., honeycomb channels) can be used for support, effectively inhibiting the aggregation and sintering of grains at high temperatures. This enables the calcium-based adsorbent of the present invention to achieve long-term and stable cyclic adsorption operation, and has excellent prospects for industrial application.

[0025] 3. Microspheres are calcined at high temperature in an inert atmosphere, causing the organic components to undergo in-situ pyrolysis to form a hydrophobic carbon film. This film effectively blocks the physical or chemical occupancy of water molecules in the flue gas, significantly reducing the competitive adsorption of water vapor and ensuring the high selectivity and chemical stability of the adsorbent for carbon dioxide in humid flue gas. Attached Figure Description

[0026] Figure 1 This is a kinetic curve showing the change of CO2 adsorption capacity over time for the adsorbent samples obtained in Examples 1-5 of this invention.

[0027] Figure 2 This is a kinetic curve showing the change of CO2 adsorption rate over time for the adsorbent samples obtained in Examples 1-5 of this invention.

[0028] Figure 3The graph shows the change in CO2 adsorption capacity of the adsorbent samples obtained in Examples 1-5 of this invention after 15 calcination-carbonation cycles.

[0029] Figure 4 This is a SEM image of the adsorbent prepared in Example 1 of the present invention.

[0030] Figure 5 This is a flowchart of the present invention.

[0031] Figure 6 The graphs show the kinetic curves of the CO2 adsorption capacity of the adsorbent samples obtained in Examples 6-8 of this invention as a function of time.

[0032] Figure 7 The graphs show the kinetic curves of the CO2 adsorption rate of the adsorbent samples obtained in Examples 6-8 of this invention as a function of time.

[0033] Figure 8 The graph shows the change in CO2 adsorption capacity of the adsorbent samples obtained in Examples 6-8 of this invention after 15 calcination-carbonation cycles. Detailed Implementation

[0034] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0035] Example 1

[0036] A method for preparing a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent includes the following steps:

[0037] S1. Preparation of stabilizer gel: Add 2g xanthan gum to 100mL of deionized water, heat and stir at 85℃ for 1h to form a uniform gel, and obtain xanthan gum gel with a mass percentage concentration of 2%.

[0038] S2. Preparation of template solution: Dissolve 1g of cyclodextrin in 100mL of water to obtain a cyclodextrin solution with a mass percentage concentration of 1%.

[0039] S3. Preparation of precursor mixture: Calcium nitrate, calcium stearate (as the first precursor material), and manganese nitrate tetrahydrate (as the second precursor material) are dissolved in water, wherein the Ca:Mn molar ratio is 100:15.

[0040] S4. Preparation of supramolecular mixture: The cyclodextrin solution and xanthan gum gel were mixed at a mass ratio of 1:2 and stirred at 85℃ for 1 h to obtain a supramolecular mixture.

[0041] S5. Microsphere Formation and Pore Formation: The supramolecular mixture was added dropwise to the precursor mixture using a coaxial droplet technique, with a volume ratio of 1:3 between the supramolecular mixture and the precursor mixture. The resulting microspheres were soaked in a constant-temperature water bath for 48 hours, then removed and directionally frozen using cryogenic casting technology (an existing technique, not described in detail here). The microspheres were then placed in an ultra-low temperature freeze dryer and sublimated at -60°C for 24 hours to obtain the dried product (i.e., microspheres with honeycomb-like pores distributed radially from the center to the surface).

[0042] S6. Calcination: The dried material is placed in a muffle furnace and calcined at 850°C for 1.5 h under a nitrogen atmosphere to obtain a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent.

[0043] Example 2

[0044] This embodiment is the same as the basic steps of embodiment 1, except that: based on embodiment 1, only the ratio of the first precursor material to the second precursor material is changed so that the molar ratio of Ca:Mn is adjusted to 100:3.

[0045] Example 3

[0046] The basic steps of this embodiment are the same as those of Embodiment 1, except that the mass percentage concentration of xanthan gum is adjusted to 0.8% based on Embodiment 1.

[0047] Example 4

[0048] The basic steps of this embodiment are the same as those of Embodiment 1, except that: based on Embodiment 1, the template agent cyclodextrin is replaced with microcrystalline cellulose, and the mass percentage concentration is kept at 1%.

[0049] Example 5

[0050] The basic steps of this embodiment are the same as those of Embodiment 1, except that the calcination temperature is adjusted to 800℃ based on Embodiment 1.

[0051] Experimental Results and Analysis

[0052] The CO2 cyclic adsorption performance of the adsorbents prepared in Examples 1-5 was tested under the following conditions: calcination regeneration at 850℃ and adsorption at 450℃. At 450℃, the volume of carbon dioxide and water vapor accounted for 15% and 5% of the total gas volume, respectively. The adsorption performance test results are as follows:

[0053] The adsorbent prepared in Example 1 has clear honeycomb-shaped channels and a hydrophobic carbon film distributed on its surface. After 15 cycles of adsorption, the capacity retention rate is over 90%.

[0054] The adsorbent prepared in Example 2 had a high initial capacity due to its low manganese content, but it exhibited agglomeration and sintering after 15 cycles, and its stability was slightly lower than that in Example 1, demonstrating the superiority of the Ca:Mn molar ratio of 100:15.

[0055] The adsorbent prepared in Example 3 has a low gel viscosity, which reduces the squeezing force on the components during ice crystal growth, resulting in thinner honeycomb pore walls and a decrease in material mechanical strength. However, the initial adsorption rate is extremely fast, demonstrating the significant improvement in mass transfer brought about by "directional pore formation".

[0056] In Example 4, although microcrystalline cellulose can play a pore-forming role, due to the lack of cyclodextrin's cavity complexing ability, the dispersion uniformity of calcium / manganese active sites in the adsorbent is slightly inferior to that in Example 1, and the adsorption capacity is reduced by about 12.3% compared to Example 1.

[0057] In Example 5, calcium stearate underwent near-complete pyrolysis at 800°C, forming an effective hydrophobic interface, and the adsorbent exhibited good selectivity in the water-containing flue gas. However, due to the slightly lower temperature, the calcium-based precursor did not decompose completely, and the content of the effective active component of the adsorbent was slightly lower than in Example 1.

[0058] Figure 1 The kinetic curves of CO2 adsorption capacity change over time for the adsorbent samples obtained in Examples 1-5 are shown. Figure 1 middle, This indicates the mass of carbon dioxide that each gram of adsorbent can absorb; g represents grams. Figure 2 The kinetic curves of CO2 adsorption rate versus time for the adsorbent samples obtained in Examples 1-5 are shown. Figure 2 middle, This indicates the mass of carbon dioxide that each gram of adsorbent can absorb per minute, i.e., the CO2 adsorption rate per gram of adsorbent. min means minutes.

[0059] Depend on Figure 1 and Figure 2 It can be seen that the series of adsorbents prepared in Examples 1-5 of this invention exhibit a synergistic effect of high adsorption capacity and fast kinetic response during CO2 capture. For example... Figure 1 As shown, the equilibrium adsorption capacities of the adsorbent samples in each embodiment are all in the high range of 0.32 g / g to 0.43 g / g. Among them, Example 1 shows the best performance, with an equilibrium adsorption capacity as high as approximately 0.425 g / g. Figure 2 It can be seen that, within the first 4 minutes of the adsorption reaction, all examples maintained extremely high adsorption rates, with peak rates stabilizing between 0.048 and 0.052 g / (g·min). The adsorption rate began to decline after 4 minutes, which is consistent with... Figure 1 This corresponds to the trend of the gradually decreasing slope of the adsorption amount.

[0060] By comparison with traditional CO2 adsorbents:

[0061] (1) In terms of adsorption capacity, the adsorption capacity of traditional adsorbents under the same conditions is usually only 0.08-0.18 g / g, while the capacity of the samples obtained in Examples 1-5 of this invention is increased by more than 150%.

[0062] (2) Regarding the adsorption rate, traditional particulate adsorbents are often limited by internal diffusion resistance, and the rate curve often shows a slow, gradual decay. However, this invention optimizes the gas diffusion path by combining coaxial dripping with freeze-drying technology, so that the adsorbent can maintain a high rate before approaching saturation, which is significantly better than traditional particulate adsorbents.

[0063] Figure 3 The graph shows the change in CO2 adsorption capacity of the adsorbent samples obtained in Examples 1-5 after 15 calcination-carbonation cycles. Figure 3 It is known that, compared with traditional calcium-based or alkali metal-based adsorbents, the adsorption capacity of traditional adsorbents usually decreases sharply by 30% to 50% after multiple cycles under the same conditions due to pore collapse caused by high-temperature sintering. However, the adsorbent of this invention retains more than 85% of its capacity after 15 cycles, demonstrating extremely strong anti-sintering performance.

[0064] Figure 4 SEM images of the adsorbent prepared in Example 1 are shown, revealing honeycomb-like channels that radiate from the center to the surface of the microspheres. Figure 5 The method flowchart of the present invention is shown, by Figure 5 The specific preparation steps of the adsorbent of the present invention are as follows.

[0065] Example 6

[0066] A method for preparing a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent includes the following steps:

[0067] S1. Prepare stabilizer gel, template agent solution and precursor mixture containing calcium source and manganese source respectively.

[0068] The precursor mixture is prepared by mixing a first precursor material and a second precursor material in water. The first precursor material includes a calcium skeletal source and a hydrophobic modifier. The calcium skeletal source is calcium chloride, and the hydrophobic modifier is calcium stearate. The second precursor material is manganese nitrate tetrahydrate. The molar ratio of the first precursor material to the second precursor material is calculated based on the metallic elements Ca and Mn, and the molar ratio of Ca in the first precursor material to Mn in the second precursor material is 100:3.

[0069] S2. The template agent solution and the stabilizer gel are mixed to form a supramolecular mixture with a supramolecular complex structure. The template agent solution is a cyclodextrin solution with a mass percentage concentration of 0.5% for cyclodextrin. The stabilizer gel is a xanthan gum gel with a mass percentage concentration of 1.5% for xanthan gum.

[0070] In step S2, the mass ratio of xanthan gum gel to cyclodextrin solution is 1:1.

[0071] S3. The supramolecular mixture is added to the precursor mixture via coaxial dropwise addition to form microspheres through contact reaction, and the microspheres are then soaked and aged.

[0072] In step S3, the volume ratio of the supramolecular mixture to the precursor mixture is 1:3.

[0073] S4. Take out the microspheres and perform directional freezing treatment to guide the controlled growth of ice crystals, thereby compressing the components for directional rearrangement. Then freeze-dry the microspheres to sublimate the ice crystals in the microspheres and form honeycomb-shaped channels that are distributed in a divergent manner from the center to the surface of the microspheres.

[0074] In step S4, the freeze-drying is ultra-low temperature freeze-drying at a temperature of -60°C.

[0075] S5. The microspheres are calcined at high temperature under an inert atmosphere, causing the organic components to undergo in-situ pyrolysis to form a hydrophobic carbon film. This induces manganese doping to create oxygen vacancies, thereby obtaining a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent. The honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent includes CaO, CaMnO3, and Ca4Mn3O4. 10 .

[0076] In step S5, the inert atmosphere is nitrogen, and the calcination temperature and time are 800℃ and 1h, respectively.

[0077] This embodiment utilizes the excellent biocompatibility of xanthan gum to construct a stable matrix framework and innovatively introduces cyclodextrin as a template agent. The unique supramolecular cavity structure of cyclodextrin enables uniform molecular-level complexation with the metal precursor, ensuring a high degree of dispersion of pore-forming sites. Through cryo-casting technology, the controlled growth of ice crystals generates a squeezing effect that guides the directional rearrangement of components. During the subsequent freeze-drying process, the sublimated ice crystals leave behind honeycomb-like channels that diffuse from the center to the surface of the spheres.

[0078] Example 7

[0079] A method for preparing a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent includes the following steps:

[0080] S1. Prepare stabilizer gel, template agent solution and precursor mixture containing calcium source and manganese source respectively.

[0081] The precursor mixture is prepared by mixing a first precursor material and a second precursor material with water. The first precursor material includes a calcium skeletal source and a hydrophobic modifier. The calcium skeletal source is calcium chloride, and the hydrophobic modifier is calcium stearate. The second precursor material is manganese nitrate tetrahydrate. The molar ratio of the first precursor material to the second precursor material is calculated based on the metallic elements Ca and Mn, and the molar ratio of Ca in the first precursor material to Mn in the second precursor material is 100:15.

[0082] S2. The template agent solution and the stabilizer gel are mixed to form a supramolecular mixture with a supramolecular complex structure. The template agent solution is a microcrystalline cellulose solution with a mass percentage concentration of 1.5% for microcrystalline cellulose. The stabilizer gel is a xanthan gum gel with a mass percentage concentration of 2% for xanthan gum.

[0083] In step S2, the mass ratio of xanthan gum gel to cyclodextrin solution is 2:1.

[0084] S3. The supramolecular mixture is added to the precursor mixture via coaxial dropwise addition to form microspheres through contact reaction, and the microspheres are then soaked and aged.

[0085] In step S3, the volume ratio of the supramolecular mixture to the precursor mixture is 1:5.

[0086] S4. Take out the microspheres and perform directional freezing treatment to guide the controlled growth of ice crystals, thereby compressing the components for directional rearrangement. Then freeze-dry the microspheres to sublimate the ice crystals in the microspheres and form honeycomb-shaped channels that are distributed in a divergent manner from the center to the surface of the microspheres.

[0087] In step S4, the freeze-drying is ultra-low temperature freeze-drying at a temperature of -70°C.

[0088] S5. The microspheres are calcined at high temperature under an inert atmosphere, causing the organic components to undergo in-situ pyrolysis to form a hydrophobic carbon film. This induces manganese doping to create oxygen vacancies, thereby obtaining a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent. The honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent includes CaO, CaMnO3, and Ca4Mn3O4. 10 .

[0089] In step S5, the inert atmosphere is nitrogen, and the calcination temperature and time are 850℃ and 1.5h, respectively.

[0090] Example 8

[0091] A method for preparing a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent includes the following steps:

[0092] S1. Prepare stabilizer gel, template agent solution and precursor mixture containing calcium source and manganese source respectively.

[0093] The precursor mixture is prepared by mixing a first precursor material and a second precursor material with water. The first precursor material includes a calcium skeletal source and a hydrophobic modifier. The calcium skeletal source is calcium nitrate, and the hydrophobic modifier is calcium stearate. The second precursor material is manganese nitrate tetrahydrate. The molar ratio of the first precursor material to the second precursor material is calculated based on the metallic elements Ca and Mn, and the molar ratio of Ca in the first precursor material to Mn in the second precursor material is 100:30.

[0094] S2. The template agent solution and the stabilizer gel are mixed to form a supramolecular mixture with a supramolecular complex structure. The template agent solution is a polyethylene solution with a polyethylene mass percentage concentration of 3%. The stabilizer gel is a sodium alginate gel with a sodium alginate mass percentage concentration of 2.5%.

[0095] In step S2, the mass ratio of sodium alginate gel to polyethylene solution is 5:1.

[0096] S3. The supramolecular mixture is added to the precursor mixture via coaxial dropwise addition to form microspheres through contact reaction, and the microspheres are then soaked and aged.

[0097] In step S3, the volume ratio of the supramolecular mixture to the precursor mixture is 1:6.

[0098] S4. Take out the microspheres and perform directional freezing treatment to guide the controlled growth of ice crystals, thereby compressing the components for directional rearrangement. Then freeze-dry the microspheres to sublimate the ice crystals in the microspheres and form honeycomb-shaped channels that are distributed in a divergent manner from the center to the surface of the microspheres.

[0099] In step S4, the freeze-drying is ultra-low temperature freeze-drying at a temperature of -80°C.

[0100] S5. The microspheres are calcined at high temperature under an inert atmosphere, causing the organic components to undergo in-situ pyrolysis to form a hydrophobic carbon film. This induces manganese doping to create oxygen vacancies, thereby obtaining a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent. The honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent includes CaO, CaMnO3, and Ca4Mn3O4. 10 .

[0101] In step S5, the inert atmosphere is nitrogen, and the calcination temperature and time are 900℃ and 2h, respectively. Step S5 completes the carbonization of the biomatrix, the modification of calcium stearate, and the decomposition and transformation of the calcium-based precursor.

[0102] The adsorbents prepared in Examples 6-8 of this invention exhibit a synergistic effect of high adsorption capacity and fast kinetic response during CO2 capture. Figure 6 The kinetic curves of CO2 adsorption capacity versus time for the adsorbent samples obtained in Examples 6-8 of this invention are shown. Figure 7 The kinetic curves of CO2 adsorption rate versus time for the adsorbent samples obtained in Examples 6-8 of this invention are shown. Figure 8 The graph shows the change in CO2 adsorption capacity of the adsorbent samples obtained in Examples 6-8 of the present invention after 15 calcination-carbonation cycles.

[0103] like Figure 6 As shown, the equilibrium adsorption capacity of the samples in each embodiment is in the range of 0.31 g / g to 0.34 g / g, with the adsorption capacity of Example 7 reaching as high as 0.34 g / g.

[0104] like Figure 7 As shown, all examples maintained a high adsorption rate during the first 5 minutes of the adsorption reaction, with the peak rate stabilizing between 0.048 and 0.050 g / (g·min). The adsorption rate began to decline after 5 minutes.

[0105] like Figure 8 As shown, the adsorbents prepared in Examples 6-8 all maintained a capacity retention rate of over 85% after test cycles, exhibiting extremely strong stability. Among them, Example 7 showed the most outstanding stability, maintaining optimal adsorption efficiency even after long-term operation.

[0106] Coaxial droplet addition technology: This technology uses coaxial nested needles to introduce the gel component as the dispersed phase. The constant shear force of the external fluid overcomes the surface tension of the gel, enabling the miniaturization and discretization of droplets. This technique effectively solves the technical challenges of uneven particle size and easy adhesion in the micro-titration of high-viscosity materials, thereby obtaining microspheres with regular structures and controllable morphology.

[0107] In the precursor system of this invention, calcium stearate is added in addition to calcium nitrate. During the high-temperature calcination stage, the long carbon chains of calcium stearate undergo in-situ pyrolysis, forming a hydrophobic carbon film on the surface of the active sites of calcium oxide and on the pore walls.

[0108] When the adsorbent prepared in this invention adsorbs CO2, the electron transfer between Mn ions of different valence states in the adsorbent disrupts the electroneutrality of the calcium-based adsorbent lattice, thereby generating positively charged oxygen vacancies to compensate for the charge imbalance. The formation of these oxygen vacancies initiates a dynamic process.

[0109] The dynamic process is as follows: driven by energy, lattice oxygen (i.e., O) 2-Oxygen vacancies migrate to the surface to fill vacancies, transforming into highly active surface-adsorbed oxygen or directly participating in reactions. This process establishes a continuous "oxygen vacancy generation and migration" cycle, promoting CO2 production. 2 The continuous reaction between CaO and CaO.

[0110] Ca4Mn3O 10 The components do not react with CaMnO3, maintaining structural stability throughout the cycle. They are uniformly dispersed within the CaO adsorbent particles, achieving effective separation of active sites. This prevents the migration and aggregation of CaO particles. The physical barrier provided by these highly stable supports is crucial for improving the overall anti-sintering properties of the adsorbent. Therefore, combining the electronic properties of manganese with the high reactivity of calcium achieves the dual benefits of "adsorption capacity and stability."

[0111] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent, characterized in that, Includes the following steps: S1. Prepare stabilizer gel, template agent solution and precursor mixture containing calcium source and manganese source respectively; the precursor mixture is prepared by adding a first precursor material and a second precursor material to water and mixing them. The first precursor material includes a skeleton calcium source and a hydrophobic modifier. The skeleton calcium source is calcium chloride or calcium nitrate. The hydrophobic modifier is calcium stearate. The second precursor material is manganese nitrate tetrahydrate. S2. The template agent solution is mixed with the stabilizer gel to form a supramolecular mixture with a supramolecular complex structure. The template agent solution is at least one of cyclodextrin solution, microcrystalline cellulose solution, and polyethylene solution. The stabilizer gel is at least one of xanthan gum gel and sodium alginate gel. S3. The supramolecular mixture is added to the precursor mixture using coaxial dropping technology to form microspheres through a contact reaction, and the microspheres are then soaked and aged. S4. Take out the microspheres and perform directional freezing treatment to guide the controlled growth of ice crystals, thereby squeezing the components for directional rearrangement. Then freeze-dry the microspheres to sublimate the ice crystals in the microspheres and form honeycomb-shaped channels that are distributed in a divergent manner from the center to the surface of the microspheres. S5. The microspheres are calcined at high temperature under an inert atmosphere, causing the organic components to undergo in-situ pyrolysis to form a hydrophobic carbon film, and inducing manganese doping to form oxygen vacancies, thereby obtaining a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent. The honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent includes CaO, CaMnO3, and Ca4Mn3O4. 10 .

2. The method for preparing a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent according to claim 1, characterized in that: The stabilizer in the stabilizer gel has a mass percentage concentration of 0.8% to 3%.

3. The method for preparing a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent according to claim 1, characterized in that: The template agent in the template agent solution has a mass percentage concentration of 0.5% to 3%.

4. The method for preparing a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent according to claim 1, characterized in that: The molar ratio of the first precursor material to the second precursor material is calculated based on the metallic elements Ca and Mn, and the molar ratio of Ca in the first precursor material to Mn in the second precursor material is 100:(3~30).

5. The method for preparing a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent according to claim 1, characterized in that: In step S2, the mass ratio of the stabilizer gel to the template agent solution is (1~5):

1.

6. The method for preparing a honeycomb-structured biomatrix-mediated hydrophobic calcium-based adsorbent according to claim 1, characterized in that: In step S3, the volume ratio of the supramolecular mixture to the precursor mixture is 1:(2~10).

7. The method for preparing a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent according to claim 1, characterized in that: In step S4, the freeze-drying is ultra-low temperature freeze-drying, with a temperature of -60 to -80°C.

8. The method for preparing a honeycomb-structured bio-matrix-mediated hydrophobic calcium-based adsorbent according to claim 1, characterized in that: In step S5, the inert atmosphere is a nitrogen atmosphere, and the calcination temperature and time are 800~900℃ and 1~2h, respectively.

Images