A porous adsorbent with high adsorption efficiency and high desorption capacity and a preparation method thereof

Abstract

The present application relates to the technical field of porous adsorption material, and discloses a porous adsorbent with high adsorption efficiency and high desorption capacity and a preparation method thereof, wherein the porous adsorbent is prepared from raw materials including 15-25 parts of silica gel powder, 25-35 parts of ZSM-5 type zeolite powder, 20-25 parts of wood active carbon powder, 10-20 parts of synthetic resin powder and 10-15 parts of sodium alginate powder; the preparation method comprises the following steps: mixing the dry powders, mixing micron-sized ice powder and mechanically high-pressure dry pressing into primary particles under an environment below the freezing point; then, the particles are put into a deep cold main crosslinking solution containing calcium ions, so that the sodium alginate is crosslinked and solidified while being slowly hydrated in situ, and finally, vacuum freeze-drying is performed to remove the internal solid micron-sized ice crystals by direct sublimation to be shaped.The present application effectively avoids the pore wall shrinkage and collapse and the pore blockage in the forming process through the cooperation of ice crystal phase change occupation and deep cold in-situ crosslinking, builds a ladder-type through mass transfer channel, and significantly reduces the internal diffusion resistance.

Description

Technical Field

[0001] This invention relates to the field of porous adsorption materials technology, specifically to a porous adsorbent with high adsorption efficiency and high desorption capacity, and its preparation method. Background Technology

[0002] Porous adsorbent materials play an important role in applications such as industrial waste gas treatment, water purification, and mixture separation. When dealing with complex substances in actual industrial processes, adsorbent materials composed of a single matrix often struggle to capture both polar and non-polar molecules. Therefore, combining powders with different pore sizes and surface chemical properties has become a major approach to improving the overall performance of adsorbents.

[0003] To adapt to the operating conditions of industrial packed beds and reduce pressure drop during fluid flow, powdered adsorbent matrices must be processed into macroscopic particles of specific sizes. Currently, conventional composite adsorbent molding relies heavily on wet granulation processes, which involve introducing a liquid binder into the mixed powder followed by kneading and mechanical extrusion. However, in this process, the fluid liquid binder inevitably penetrates and coats the surface of the inorganic adsorbent matrix, thereby blocking the inherent micropores and mesopores of the material over a large area, resulting in the ineffective consumption of effective adsorption sites. In the subsequent conventional heating, drying, and dehydration stages, the gas-liquid interfacial tension generated during the phase change of the liquid solvent evaporation induces significant capillary contraction stress within the particles, causing the originally formed micropores to be squeezed, contracted, and even irreversibly physically collapsed.

[0004] The combined effects of physical blockage and structural collapse result in the loss of continuous three-dimensional mass transfer channels within the formed composite adsorbent, with some areas even developing dense, plate-like layers. This deterioration of the internal structure directly leads to a sharp increase in the penetration and diffusion resistance of adsorbate molecules within the particles, manifesting as a sluggish overall adsorption rate on a macroscopic level. Simultaneously, during desorption and regeneration, due to pore blockage and the lack of smooth outward flow, deeply adsorbed molecules struggle to overcome steric hindrance and successfully escape, causing a severe mismatch between adsorption and desorption kinetics. This directly impacts the adsorbent's cycle life and operational efficiency. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a porous adsorbent with high adsorption efficiency and high desorption capacity, and its preparation method. This solves the problems that existing adsorbent materials typically suffer from: mismatch between adsorption and desorption rates; easy collapse and blockage of internal pores during the pressing process of molded adsorbents; and increased mass transfer resistance due to uneven distribution of binder during multi-component composite molding.

[0006] To achieve the above objectives, the present invention provides a porous adsorbent with high adsorption efficiency and high desorption capacity, using the following technical solution: A porous adsorbent with high adsorption efficiency and high desorption capacity, the porous adsorbent being made from raw materials comprising the following parts by weight: silica gel powder: 15-25 parts; ZSM-5 type zeolite powder: 25-35 parts; wood-based activated carbon powder: 20-25 parts; synthetic resin powder: 10-20 parts; sodium alginate powder: 10-15 parts.

[0007] By employing the above technical solution, this invention utilizes a specific ratio of inorganic powders and organic macromolecules to construct a porous system with graded distribution characteristics. Specifically, silica gel powder, with its abundant surface hydroxyl groups and nanoscale pore size, is mainly used to capture polar small molecules; combined with the uniform microporous structure and shape-selective adsorption sites of ZSM-5 zeolite powder, and further supplemented by the well-developed micropores and mesopores of wood-based activated carbon powder, it collectively provides the basis for the material's broad-spectrum physical adsorption. Simultaneously, the hydrophobic framework, such as benzene rings, contained in the synthetic resin powder achieves adsorption of non-polar organic matter through partitioning and plays a role in regulating the mesopore distribution within the overall framework. Furthermore, sodium alginate powder, as a molding matrix, firmly anchors the dispersed powders in a continuous three-dimensional network after in-situ cross-linking, effectively overcoming the problem of powder agglomeration. This synergistic mechanism among multiple components not only accommodates the adsorption of both polar and non-polar target substances but also opens up a stepped mass transfer channel from micropores to macropores within the material, thereby significantly reducing the diffusion resistance throughout the adsorption and desorption cycle.

[0008] Preferably, the porous adsorbent has a macroscopic morphology of particles with a diameter of 3 to 5 mm, and the interior of the porous adsorbent has micron-sized three-dimensional channels formed by the in-situ sublimation and removal of solid micron-sized ice crystals with a particle size of 50 to 200 μm.

[0009] By employing the above technical solution, the adsorbent is processed into particles of a specific diameter, directly ensuring that it can maintain a suitable bed porosity in industrial packed beds and effectively reducing the pressure drop during fluid flow. More importantly, the micron-sized three-dimensional channels left by the phase transition and sublimation of solid ice crystals constitute a macroscopic pathway for adsorbate molecules to reach deep into the particles, significantly shortening the internal diffusion path. Because the micron-sized solid ice crystals sublimate directly during the pore-forming process, the capillary contraction force accompanying liquid water evaporation is avoided, thus the channels maintain their original three-dimensional physical morphology, fundamentally eliminating the hidden danger of pore wall shrinkage and collapse, and ensuring that the final product has excellent macroscopic specific surface area and porosity.

[0010] Preferably, the synthetic resin powder is a styrene-divinylbenzene copolymer that has undergone post-crosslinking and pore-expanding treatment, and is prepared by a method comprising the following steps: Styrene accounting for 60%~75% of the total mass of the oil phase, divinylbenzene accounting for 10%~20% of the total mass of the oil phase, toluene accounting for 15%~20% of the total mass of the oil phase, and benzoyl peroxide accounting for 1.0%~2.0% of the total mass of the aforementioned styrene and divinylbenzene monomers are mixed evenly to obtain the oil phase; In an aqueous phase containing a polyvinyl alcohol suspending dispersant, the oil phase is added at a mass ratio of (3~5):1. After reacting at a constant temperature of 75~85℃ for 6~8 hours, the temperature is raised to 90~95℃ for 2~3 hours to obtain copolymer microspheres. The dried copolymer microspheres were placed in 1,2-dichloroethane at a mass-volume ratio of 1g:(4~6)mL and swollen for 12~24 hours. Then, anhydrous aluminum chloride of 20%~30% of the mass of the microspheres was added, and the mixture was refluxed at 80~85℃ for 8~12 hours. After the reaction was completed, the microspheres were washed, dried and pulverized.

[0011] By employing the above-mentioned technical solution, the polymerization process of the synthetic resin utilizes toluene as a pore-forming agent to build an initial pore network. Subsequently, anhydrous aluminum chloride is introduced as a Lewis acid catalyst to induce Friedel-Crafts alkylation reactions between the residual vinyl groups within the copolymer network and adjacent benzene rings. This specific chemical reaction can establish additional methylene crosslinking bridges between the already formed microsphere framework, rigidly solidifying the fully swollen polymer segments, thereby deriving a rich mesoporous structure. Relying on this post-crosslinking pore-expanding mechanism, the synthetic resin powder achieves a significantly higher specific surface area and a highly developed mesoporous network than conventional methods, significantly accelerating the diffusion and adsorption rates of macromolecular organic matter within it.

[0012] Preferably, the physicochemical parameters of the raw material meet the following conditions: The silica gel powder has a pore size distribution of 2~10nm and a particle size of 200~400 mesh; the ZSM-5 zeolite powder has a silica-alumina ratio of 20~100 and a particle size of 300~500 mesh; the wood-based activated carbon powder has an iodine adsorption value ≥800mg / g and a particle size of 200~300 mesh; the sodium alginate powder is a polymer composed of block copolymers of β-D-mannuronic acid and α-L-guluronic acid, with a molecular weight distribution between 10000~600000.

[0013] By employing the above technical solutions, the strict definition of the particle size range of each inorganic powder ensures that particles of different sizes can achieve close physical packing during mixing. Simultaneously, controlling the silica-alumina ratio of ZSM-5 zeolite imparts a suitable surface acidity, and high-iodine-value activated carbon lays a solid foundation for adsorption capacity. Notably, limiting the molecular weight of sodium alginate powder to a specific range ensures that its polymer chains carry sufficient carboxyl crosslinking sites to provide the necessary structural strength for the subsequent gel framework, while effectively preventing a surge in hydration liquid viscosity caused by exceeding the molecular weight limit, thus guaranteeing the smoothness of the preparation process.

[0014] Secondly, the present invention provides a method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity, employing the following technical solution: A method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity includes the following steps: S1. Prepare silica gel powder, ZSM-5 zeolite powder and wood activated carbon powder according to the weight parts and put them into a fluidized bed. Spray the pre-activation liquid and pass hot air through for flash evaporation treatment to obtain absolutely dry inorganic powder. S2. The absolutely dry inorganic powder obtained in step S1, the synthetic resin powder prepared according to the stated weight parts, and the sodium alginate powder are mixed by pure physical mixing in an environment with a relative humidity of ≤40% to obtain a dry mixed powder. S3. Mix 20-50 parts by weight of micron-sized ice powder into the dry powder mixture of step S2 and mix evenly. Then apply a mechanical high pressure of 10-30 MPa without adding any liquid water to compress it into primary particles. S4. The primary particles pressed out in step S3 are directly immersed in a cryogenic main crosslinking liquid containing calcium ions at a temperature controlled at -15℃~-20℃ for low-speed stirring and soaking reaction, so that sodium alginate undergoes crosslinking and curing simultaneously while being hydrated in situ. S5. Remove the cryogenically solidified granules and place them in a vacuum freeze dryer for continuous freeze drying, so that the internal solid ice can be directly sublimated and removed to obtain the finished product.

[0015] By adopting the above technical solution, this process route fundamentally avoids the inherent drawback of conventional wet granulation, where binders easily clog pores. During the activation stage, relying on hot air flash evaporation technology, the active components in the pre-activated liquid are uniformly anchored on the surface of the inorganic powder, and the solvent is instantly stripped away. Subsequent homogenization operations are strictly carried out in an extremely low humidity environment to cut off the pathway of sodium alginate's hygroscopic swelling and prevent the formation of local clumps. To construct internal pores, micron-sized ice powder is introduced into the preparation process as a solid-state phase change template and endogenous hydration medium; utilizing a low-temperature, high-pressure environment, the material is compacted under dry conditions where the ice powder has not melted, thereby establishing the initial mechanical strength of the primary particles.

[0016] In the crucial cryogenic in-situ crosslinking process, the particles are placed in a cryogenic liquid environment close to the freezing point of sodium alginate. At this time, external calcium ions slowly infiltrate, and the crosslinking liquid wetting causes a small amount of slow thawing on the surface of the micron-sized ice crystals inside the particles. The released water drives localized hydration of the sodium alginate. The exposed macromolecular carboxyl groups from the hydration then coordinate with the infiltrated calcium ions, constructing a stable crosslinking network. The core reaction formula is: ; Due to the cryogenic conditions, the rates of water molecule dispersion and polymer chain segment extension are suppressed in both directions. This extremely slow cross-linking dynamic effectively prevents the particle surface from forming a crust too quickly, ensuring that the cross-linking reaction can proceed uniformly from the surface to the interior. Ultimately, the remaining solid ice phase sublimates directly under vacuum freezing conditions, bypassing the liquid phase stage, completely eliminating the pore wall shrinkage force caused by liquid film tension, and replicating the space originally occupied by ice crystals into interconnected macroscopic channels.

[0017] Preferably, in step S1: the pre-activation solution is an anhydrous calcium chloride anhydrous ethanol solution with a mass fraction of 0.1%~0.5%, or an anhydrous ferric chloride anhydrous ethanol solution with a mass fraction of 0.1%~0.5%; the amount of the pre-activation solution is 3%~8% of the total mass of the inorganic powder; the flash evaporation conditions are: passing hot air at 40~50℃ for flash evaporation for 10~20 minutes to rapidly evaporate the ethanol solvent.

[0018] By employing the above technical solution and leveraging the excellent volatility potential of anhydrous ethanol, hot air flash evaporation promotes the uniform deposition of calcium or iron ions on the outer surface and even deep within the pores of the inorganic powder in a very short time. This strategy of pre-positioning crosslinking ions allows them to act as endogenous crosslinking nodes in the subsequent cryogenic crosslinking reaction, forming a synergistic in-situ solidification effect with the externally infiltrated sodium alginate matrix, further enhancing the structural cohesion of the entire porous framework.

[0019] Preferably, in step S3: the particle size of the micron-sized ice powder is 50~200μm; the mixing of the micron-sized ice powder and the pressing and molding operation are carried out under the condition of ambient temperature control of -5℃~0℃; the diameter of the primary particles pressed is 3~5mm.

[0020] By employing the above technical solution, the pre-selected ice powder with a specific particle size essentially serves as a dimensional template for the interconnected pores within the final product. Compared to conventional mesopores, the pore size of 50–200 μm is sufficient to serve as the main channels for fluid permeation, significantly reducing the fluid resistance when the adsorbate diffuses into the particle core. Combined with a strictly controlled sub-zero forming environment, the ice powder undergoes only the necessary plastic deformation to conform to the gaps between powder particles under high mechanical pressure, completely avoiding phase transformation and melting, thus fulfilling its physical positioning function as a pore-forming template.

[0021] Preferably, in step S4: the cryogenic main crosslinking solution is a calcium chloride aqueous solution with a mass fraction of 25%~30%, and hydroquinone with a mass fraction of 0.05%~0.2% is also added to the cryogenic main crosslinking solution; the conditions for the low-speed stirring soaking reaction are: soaking reaction for 1~2 hours at a stirring speed of 10~20 r / min.

[0022] By employing the above technical solution, the preparation of a high-concentration calcium chloride aqueous solution not only significantly lowers the freezing point of the system, ensuring good fluidity of the crosslinked liquid in the extremely low temperature range, but also, through the large osmotic pressure gradient it creates, strongly drives calcium ions to penetrate deep into the primary particles. The additional hydroquinone introduced into the system acts as an antioxidant, effectively blocking the oxidative degradation of organic matter under complex crosslinking conditions, thus ensuring the integrity of the sodium alginate molecular chain segments. Coupled with a designed low-speed stirring mechanism, sufficient time is reserved for mass transfer between the solid and liquid phases.

[0023] Preferably, in step S5, the conditions for vacuum freeze drying are: continuous freeze drying for 12 to 24 hours under conditions of vacuum degree ≤10Pa and shelf temperature gradient controlled at -20℃ gradually increasing to 25℃.

[0024] By employing the above technical solution, the system vacuum is suppressed below the 10Pa threshold, forcing the environmental pressure of the ice phase to be lower than its triple point pressure, thereby triggering a direct transition of solid water to the gaseous state. A stepped heating strategy is implemented during the freeze-drying process to mitigate the internal thermal stress concentration caused by intense heat exchange, thus avoiding the risk of particle cracking and ultimately endowing the porous adsorbent with a highly intact three-dimensional macroscopic structure.

[0025] Preferably, in step S2: the process control parameters for the pure physical homogenization are: homogenization at a speed of 30-50 r / min for 30-60 minutes at a temperature of 20-25℃.

[0026] By employing the above-mentioned technical solution, applying specific mechanical shear force for homogenization at room temperature can completely disintegrate the micro-agglomerates formed by electrostatic adsorption between dry powders. This purely physical kneading process overcomes the obstacle of significant differences in specific gravity between inorganic and organic components, enabling the mixture to achieve a highly uniform dispersion state, laying the foundation for the stable performance of each batch of products in subsequent large-scale production.

[0027] This invention provides a porous adsorbent with high adsorption efficiency and high desorption capacity, and a method for preparing the same. It offers the following advantages: 1. This invention constructs a broad-spectrum adsorption system that accommodates both polar and non-polar target analytes by compounding inorganic porous powders with different pore size distributions and surface properties with organic synthetic resin powder and sodium alginate matrix in a specific ratio. The powder components are uniformly dispersed within a three-dimensional alginate network formed through in-situ cross-linking, avoiding the pore blockage problems caused by uneven flow and excessive coating of liquid binders in traditional wet granulation. This combination of multi-component physical stacking and chemical framework establishes continuous mass transfer channels within the material, extending from micropores and mesopores to macropores, significantly reducing the internal diffusion resistance of adsorbates throughout the adsorption and desorption cycle in practical applications.

[0028] 2. This invention uses micron-sized solid ice powder as a phase-change pore-forming template, combined with an anhydrous high-pressure dry forming process in a sub-freezing environment. This allows the ice crystals to undergo only plastic deformation under mechanical stress, achieving physical occupancy within the particles. The subsequent vacuum freeze-drying process forces the internal solid ice to sublimate and escape directly without passing through the liquid phase, completely eliminating the capillary shrinkage stress caused by gas-liquid interfacial tension during the water evaporation stage in conventional wet forming. This pore-forming mechanism ensures that the micron-sized three-dimensional channels retain their initial three-dimensional morphology completely during the shaping stage, fundamentally preventing pore wall shrinkage and collapse, and endowing the formed particles with a stable macroscopic porosity.

[0029] 3. The preparation process of this invention introduces a cryogenic liquid-phase bidirectional in-situ crosslinking mechanism, in which primary particles are placed in a cryogenic calcium-containing crosslinking liquid close to the freezing point of sodium alginate for solidification reaction. The cryogenic environment simultaneously restricts the inward permeation and diffusion rate of water molecules and the unfolding hydration rate of polymer chain segments, resulting in a slow and dynamic process where the swelling of sodium alginate and the subsequent coordination crosslinking of calcium ions are mutually constrained. This mechanism effectively avoids the phenomenon that the particle surface forms a dense shell due to instantaneous and intense crosslinking, hindering internal ion exchange, ensuring that calcium ions can fully penetrate into the particle core, and ultimately achieving uniformity of crosslinking density and stability of the overall mechanical structure of the adsorbent particles from the surface to the interior. Attached Figure Description

[0030] Figure 1 This is a comparison diagram of nitrogen adsorption-desorption isotherms of the present invention; Figure 2 A comparison diagram of the aperture distribution curves of the present invention is provided to highlight the invention. Figure 3 To highlight the two-dimensional correlation distribution diagram of the mechanical properties and wear resistance of the porous composite adsorbent of the present invention; Figure 4 To highlight the percentage mass loss curve of the present invention; Figure 5 To highlight the heat flow rate curve of this invention; Figure 6To highlight the dynamic breakthrough curve of the toluene component in the mixed gas of the present invention; Figure 7 To highlight the dynamic penetration curves of the corresponding samples for styrene components under the same test conditions of the present invention; Figure 8 To highlight the toluene adsorption capacity decay curve of the present invention; Figure 9 To highlight the two-dimensional correlation distribution of the initial adsorption capacity and cycle retention rate of the sample in this invention. Detailed Implementation

[0031] The technical solutions in 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.

[0032] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0033] Silica gel powder, CAS number 112926-00-8, has a mesoporous structure with a pore size distribution of 2~10nm and a particle size of 200~400 mesh.

[0034] ZSM-5 type zeolite powder, CAS number 1318-02-1, has a silicon-to-aluminum ratio (SiO2 / Al2O3) of 20~100 and a particle size of 300~500 mesh.

[0035] Wood-based activated carbon powder, CAS number 7440-44-0, microporous structure, iodine adsorption value ≥800mg / g, particle size 200~300 mesh.

[0036] Sodium alginate powder, CAS number 9005-38-3, is a linear block copolymer composed of β-D-mannuronic acid and α-L-guluronic acid linked by (1→4) bonds. Its molecular weight is between 10,000 and 600,000, and its viscosity is between 200 and 500 mPa·s (1% aqueous solution, 20℃).

[0037] Polyvinyl alcohol, CAS number 9002-89-5, is a linear polymer obtained by polymerizing vinyl acetate to obtain polyvinyl acetate and then undergoing alcoholysis. The degree of alcoholysis is 87%~89%, and the average degree of polymerization is 1700.

[0038] Preparation Example 1: This preparation example provides a method for preparing synthetic resin powder, including the following steps: Deionized water was added to a mechanically stirred reactor, along with 1.0% (by mass) of polyvinyl alcohol as a suspending agent. The mixture was heated to 45°C and stirred until dissolved, yielding an aqueous phase. Styrene (65% by mass), divinylbenzene (15% by mass), toluene (20% by mass), and benzoyl peroxide (1.5% by mass) of the aforementioned monomers (styrene and divinylbenzene) were mixed thoroughly to obtain an oil phase. The oil phase was then added to the aqueous phase at a mass ratio of 4:1, with the stirring speed controlled at 300 rpm. The temperature was slowly increased to 80℃ and kept constant for 7 hours, then increased to 92℃ for 2.5 hours to obtain white copolymer microspheres. The obtained white copolymer microspheres were filtered, washed with water and dried. The dried microspheres were placed in 1,2-dichloroethane at a mass-volume ratio of 1g:5mL to swell for 18 hours. Then anhydrous aluminum chloride at 25% of the mass of the microspheres was added and the mixture was refluxed at 82℃ for 10 hours. After the reaction was completed, the mixture was repeatedly washed with dilute hydrochloric acid and deionized water until neutral. After drying, the mixture was pulverized and passed through a 150-mesh sieve to obtain synthetic resin powder.

[0039] Preparation Example 2: This preparation example provides a method for preparing synthetic resin powder, including the following steps: Deionized water was added to a mechanically stirred reactor, along with 1.5% polyvinyl alcohol (polyvinyl alcohol by mass) as a suspending agent. The mixture was heated to 50°C and stirred until dissolved, yielding an aqueous phase. Styrene (60% by mass), divinylbenzene (20% by mass), toluene (20% by mass), and benzoyl peroxide (2.0% by mass) of the aforementioned monomers were mixed thoroughly to obtain an oil phase. The oil phase was then added to the aqueous phase at a mass ratio of 5:1, with the stirring speed controlled at 400 rpm. The mixture was slowly heated to 85°C and reacted at a constant temperature for 6 hours, followed by aging at 95°C for 2 hours to obtain white copolymer microspheres. The obtained white copolymer microspheres were filtered, washed with water, and dried. The dried microspheres were placed in 1,2-dichloroethane at a mass-volume ratio of 1g:6mL to swell for 24 hours. Then, anhydrous aluminum chloride (30% of the mass of the microspheres) was added, and the mixture was refluxed at 85°C for 8 hours. After the reaction was completed, the mixture was repeatedly washed with dilute hydrochloric acid and deionized water until neutral, dried, and pulverized through a 200-mesh sieve to obtain synthetic resin powder.

[0040] Preparation Example 3: This preparation example provides a method for preparing synthetic resin powder, including the following steps: Deionized water was added to a mechanically stirred reactor, along with 0.5% polyvinyl alcohol (PEA) as a suspending agent (based on the mass of the deionized water). The mixture was heated to 40°C and stirred until dissolved, yielding an aqueous phase. Styrene (75% by mass), divinylbenzene (10% by mass), toluene (15% by mass), and benzoyl peroxide (1.0% by mass) of the aforementioned monomers were mixed thoroughly to obtain an oil phase. The oil phase was then added to the aqueous phase at a mass ratio of 3:1, with the stirring speed controlled at 200 rpm. The mixture was slowly heated to 75°C and reacted at a constant temperature for 8 hours, followed by aging at 90°C for 3 hours to obtain white copolymer microspheres. The obtained white copolymer microspheres were filtered, washed with water, and dried. The dried microspheres were placed in 1,2-dichloroethane at a mass-volume ratio of 1g:4mL to swell for 12 hours. Then, anhydrous aluminum chloride at 20% of the mass of the microspheres was added, and the mixture was refluxed at 80°C for 12 hours. After the reaction was completed, the mixture was repeatedly washed with dilute hydrochloric acid and deionized water until neutral, dried, and pulverized through a 100-mesh sieve to obtain synthetic resin powder.

[0041] Example 1: This embodiment provides a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following components in parts by weight: Silica powder: 20 parts; ZSM-5 type zeolite powder: 30 parts; Wood-based activated charcoal powder: 20 parts; Synthetic resin powder (obtained from Preparation Example 1): 15 parts; Sodium alginate powder: 15 parts.

[0042] This embodiment also provides a method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following steps: S1. Dry pre-wetting and activation of inorganic powder surface: The formulated amounts of silica gel powder, ZSM-5 zeolite powder, and wood-based activated carbon powder are added to a fluidized bed; an anhydrous ethanol solution of anhydrous calcium chloride with a mass fraction of 0.3% is prepared as a pre-activation liquid, and the amount of pre-activation liquid is 5% of the total mass of inorganic powder; the fluidized bed is turned on, and the pre-activation liquid is evenly sprayed onto the surface of inorganic powder through a high-pressure atomizing nozzle with an atomization pressure of 0.4MPa. At the same time as spraying, hot air at 45℃ is introduced for flash evaporation treatment for 15 minutes to make the ethanol solvent evaporate rapidly, and an absolutely dry inorganic powder with dry cross-linked crystal nuclei on the surface is obtained. S2. Absolutely dry mixing of multiple components: The absolutely dry inorganic powder obtained in step S1, the formulated amount of synthetic resin powder and sodium alginate powder are put into a three-dimensional dry powder mixer and physically mixed for 45 minutes at a speed of 40r / min under an environment of 25℃ and relative humidity ≤40%. S3. Introduction of cold phase change pore-forming agent and high-pressure dry molding: In a cold room with an ambient temperature controlled at -2℃, 35 parts of micron-sized ice powder (particle size 50~200μm) are rapidly mixed into the dry powder of step S2 and mixed evenly; the cold powder is fed into a roller dry granulator, and a mechanical high pressure of 20MPa is applied without adding any liquid water. The micron-sized ice crystals are locally micro-melted under high pressure (re-icing phenomenon) to release a trace amount of interfacial water, which instantly wets and activates the sodium alginate powder to produce initial tack, and is forcibly pressed into primary particles with a diameter of 3~5mm; S4. Cryogenic liquid phase bidirectional in-situ crosslinking: Prepare a 28% calcium chloride aqueous solution in advance and add 0.1% hydroquinone. Use a refrigeration unit to keep the temperature constant at -18℃ as the cryogenic main crosslinking liquid. Put the primary particles pressed in step S3 directly into the cryogenic main crosslinking liquid. Driven by the osmotic pressure of high-concentration electrolyte, the unfrozen free water and calcium ions in the crosslinking liquid penetrate into the particle interior, so that sodium alginate undergoes crosslinking and solidification simultaneously while being hydrated in situ. Soak and react for 1.5 hours under low-speed stirring at 15r / min. S5. Vacuum freeze-drying and three-dimensional channel shaping: Take out the deeply cryogenically solidified particles, drain the surface free liquid, and lay them flat in the cold trap tray of the vacuum freeze dryer; freeze-dry continuously for 18 hours under the conditions of vacuum degree ≤10Pa and shelf temperature gradient controlled at -20℃ to gradually increase to 25℃, so that the internal solid ice is directly sublimated and removed, and the finished product is obtained.

[0043] Example 2: This embodiment provides a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following components in parts by weight: Silica powder: 25 parts; ZSM-5 type zeolite powder: 35 parts; Wood-based activated charcoal powder: 20 parts; Synthetic resin powder (obtained from Preparation Example 3): 10 parts; Sodium alginate powder: 10 parts.

[0044] This embodiment also provides a method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following steps: S1. Dry Pre-wetting Activation of Inorganic Powder Surface: The formulated amounts of silica gel powder, ZSM-5 zeolite powder, and wood-based activated carbon powder are added to a fluidized bed; an anhydrous ethanol solution of anhydrous calcium chloride with a mass fraction of 0.1% is prepared as a pre-activation liquid, and the amount of pre-activation liquid is 3% of the total mass of the inorganic powder; the fluidized bed is turned on, and the pre-activation liquid is evenly sprayed onto the surface of the inorganic powder through a high-pressure atomizing nozzle with an atomization pressure of 0.3MPa. At the same time as spraying, hot air at 40℃ is introduced for flash evaporation treatment for 20 minutes to make the ethanol solvent evaporate rapidly, and an absolutely dry inorganic powder with dry cross-linked crystal nuclei on the surface is obtained. S2. Absolutely dry mixing of multiple components: The absolutely dry inorganic powder obtained in step S1, the formulated amount of synthetic resin powder and sodium alginate powder are put into a three-dimensional dry powder mixer and mixed physically for 60 minutes at a speed of 30r / min under an environment of 20℃ and relative humidity ≤40%. S3. Introduction of cold phase change pore-forming agent and high-pressure dry molding: In a cold room with the ambient temperature controlled at 0℃, 20 parts of micron-sized ice powder (particle size 50~200μm) are quickly mixed into the dry powder of step S2 and mixed evenly; the cold powder is fed into a roller dry granulator, and a mechanical high pressure of 10MPa is applied without adding any liquid water. The micron-sized ice crystals are locally micro-melted under high pressure (re-icing phenomenon) to release a trace amount of interfacial water, which instantly wets and activates the sodium alginate powder to make it produce initial tack, and is forcibly pressed into primary particles with a diameter of 3~5mm; S4. Cryogenic liquid phase bidirectional in-situ crosslinking: Prepare a 25% calcium chloride aqueous solution in advance and add 0.05% hydroquinone. Use a refrigeration unit to keep the temperature constant at -15℃ as the cryogenic main crosslinking liquid. Put the primary particles pressed in step S3 directly into the cryogenic main crosslinking liquid. Driven by the osmotic pressure of high-concentration electrolyte, the unfrozen free water and calcium ions in the crosslinking liquid penetrate into the particle interior, so that sodium alginate undergoes crosslinking and solidification simultaneously while being hydrated in situ. Soak and react for 2 hours under low-speed stirring at 10r / min. S5. Vacuum freeze-drying and three-dimensional channel shaping: Take out the deeply cryogenically solidified particles, drain the surface free liquid, and lay them flat in the cold trap tray of the vacuum freeze dryer; freeze-dry continuously for 24 hours under the conditions of vacuum degree ≤10Pa and shelf temperature gradient controlled from -20℃ to 25℃, so that the internal solid ice is directly sublimated and removed, and the finished product is obtained.

[0045] Example 3: This embodiment provides a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following components in parts by weight: Silica powder: 15 parts; ZSM-5 type zeolite powder: 25 parts; Wood-based activated charcoal powder: 25 parts; Synthetic resin powder (obtained from Preparation Example 2): 20 parts; Sodium alginate powder: 15 parts.

[0046] This embodiment also provides a method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following steps: S1. Dry Pre-wetting Activation of Inorganic Powder Surface: The formulated amounts of silica gel powder, ZSM-5 zeolite powder, and wood-based activated carbon powder are added to a fluidized bed; an anhydrous ethanol solution of 0.5% anhydrous calcium chloride is prepared as a pre-activation liquid, and the amount of pre-activation liquid is 8% of the total mass of the inorganic powder; the fluidized bed is turned on, and the pre-activation liquid is evenly sprayed onto the surface of the inorganic powder through a high-pressure atomizing nozzle with an atomization pressure of 0.5MPa. At the same time as spraying, hot air at 50℃ is introduced for flash evaporation treatment for 10 minutes to make the ethanol solvent evaporate rapidly, and an absolutely dry inorganic powder with dry cross-linked crystal nuclei on the surface is obtained. S2. Absolutely dry mixing of multiple components: The absolutely dry inorganic powder obtained in step S1, the synthetic resin powder of the formula amount and the sodium alginate powder are put into a three-dimensional dry powder mixer and physically mixed for 30 minutes at a speed of 50r / min under an environment of 25℃ and relative humidity ≤40%. S3. Introduction of cold phase change pore-forming agent and high-pressure dry molding: In a cold room with an ambient temperature controlled at -5℃, 50 parts of micron-sized ice powder (particle size 50~200μm) are quickly mixed into the dry powder of step S2 and mixed evenly; the cold powder is fed into a roller dry granulator, and a mechanical high pressure of 30MPa is applied without adding any liquid water. The micron-sized ice crystals are locally melted under high pressure (re-icing phenomenon) to release a trace amount of interfacial water, which instantly wets and activates the sodium alginate powder to produce initial tack, and is forcibly pressed into primary particles with a diameter of 3~5mm; S4. Cryogenic liquid phase bidirectional in-situ crosslinking: Prepare a 30% calcium chloride aqueous solution and add 0.2% hydroquinone. Use a refrigeration unit to keep the temperature constant at -20℃ as the cryogenic main crosslinking liquid. Put the primary particles pressed in step S3 directly into the cryogenic main crosslinking liquid. Driven by the osmotic pressure of high-concentration electrolyte, the unfrozen free water and calcium ions in the crosslinking liquid penetrate into the particle interior, so that sodium alginate undergoes crosslinking and solidification simultaneously while being hydrated in situ. Soak and react for 1 hour under low-speed stirring at 20r / min. S5. Vacuum freeze-drying and three-dimensional channel shaping: Take out the deeply cryogenically solidified particles, drain the surface free liquid, and lay them flat in the cold trap tray of the vacuum freeze dryer; freeze-dry continuously for 12 hours under the conditions of vacuum degree ≤10Pa and shelf temperature gradient controlled at -20℃ to gradually increase to 25℃, so that the internal solid ice is directly sublimated and removed, and the finished product is obtained.

[0047] Example 4: This embodiment provides a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following components in parts by weight: Silica powder: 20 parts; ZSM-5 type zeolite powder: 30 parts; Wood-based activated charcoal powder: 20 parts; Synthetic resin powder (obtained from Preparation Example 1): 15 parts; Sodium alginate powder: 15 parts.

[0048] This embodiment also provides a method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following steps: S1. Dry Pre-wetting Activation of Inorganic Powder Surface: The formulated amounts of silica gel powder, ZSM-5 zeolite powder, and wood-based activated carbon powder are added to a fluidized bed; an anhydrous ethanol solution with a mass fraction of 0.1% anhydrous ferric chloride is prepared as a pre-activation liquid, and the amount of pre-activation liquid is 3% of the total mass of the inorganic powder; the fluidized bed is turned on, and the pre-activation liquid is evenly sprayed onto the surface of the inorganic powder through a high-pressure atomizing nozzle with an atomization pressure of 0.3MPa. At the same time as spraying, hot air at 40℃ is introduced for flash evaporation treatment for 20 minutes to make the ethanol solvent evaporate rapidly, and an absolutely dry inorganic powder with dry cross-linked crystal nuclei on the surface is obtained. S2. Absolutely dry mixing of multiple components: The absolutely dry inorganic powder obtained in step S1, the formulated amount of synthetic resin powder and sodium alginate powder are put into a three-dimensional dry powder mixer and physically mixed for 45 minutes at a speed of 40r / min under an environment of 22℃ and relative humidity ≤40%. S3. Introduction of cold phase change pore-forming agent and high-pressure dry molding: In a cold room with an ambient temperature controlled at -2℃, 35 parts of micron-sized ice powder (particle size 50~200μm) are rapidly mixed into the dry powder of step S2 and mixed evenly; the cold powder is fed into a roller dry granulator, and a mechanical high pressure of 10MPa is applied without adding any liquid water. The micron-sized ice crystals are locally micro-melted under high pressure (re-icing phenomenon) to release a trace amount of interfacial water, which instantly wets and activates the sodium alginate powder to produce initial tack, and is forcibly pressed into primary particles with a diameter of 3~5mm; S4. Cryogenic liquid phase bidirectional in-situ crosslinking: Prepare a 25% calcium chloride aqueous solution in advance and add 0.1% hydroquinone. Use a refrigeration unit to keep the temperature constant at -15℃ as the cryogenic main crosslinking liquid. Put the primary particles pressed in step S3 directly into the cryogenic main crosslinking liquid. Driven by the osmotic pressure of high-concentration electrolyte, the unfrozen free water and calcium ions in the crosslinking liquid penetrate into the particle interior, so that sodium alginate undergoes crosslinking and solidification simultaneously while being hydrated in situ. Soak and react for 2 hours under low-speed stirring at 15r / min. S5. Vacuum freeze-drying and three-dimensional channel shaping: Take out the deeply cryogenically solidified particles, drain the surface free liquid, and lay them flat in the cold trap tray of the vacuum freeze dryer; freeze-dry continuously for 18 hours under the conditions of vacuum degree ≤10Pa and shelf temperature gradient controlled at -20℃ to gradually increase to 25℃, so that the internal solid ice is directly sublimated and removed, and the finished product is obtained.

[0049] Example 5: This embodiment provides a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following components in parts by weight: Silica powder: 20 parts; ZSM-5 type zeolite powder: 30 parts; Wood-based activated charcoal powder: 20 parts; Synthetic resin powder (obtained from Preparation Example 1): 15 parts; Sodium alginate powder: 15 parts.

[0050] This embodiment also provides a method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity, comprising the following steps: S1. Dry pre-wetting and activation of inorganic powder surface: The formulated amounts of silica gel powder, ZSM-5 zeolite powder, and wood-based activated carbon powder are added to a fluidized bed; an anhydrous ethanol solution with a mass fraction of 0.5% anhydrous ferric chloride is prepared as a pre-activation liquid, and the amount of pre-activation liquid is 8% of the total mass of inorganic powder; the fluidized bed is turned on, and the pre-activation liquid is evenly sprayed onto the surface of inorganic powder through a high-pressure atomizing nozzle with an atomization pressure of 0.5MPa. At the same time as spraying, hot air at 50℃ is introduced for flash evaporation treatment for 10 minutes to make the ethanol solvent evaporate rapidly, and an absolutely dry inorganic powder with dry cross-linked crystal nuclei on the surface is obtained. S2. Absolutely dry mixing of multiple components: The absolutely dry inorganic powder obtained in step S1, the formulated amount of synthetic resin powder and sodium alginate powder are put into a three-dimensional dry powder mixer and physically mixed for 45 minutes at a speed of 40r / min under an environment of 25℃ and relative humidity ≤40%. S3. Introduction of cold phase change pore-forming agent and high-pressure dry molding: In a cold room with an ambient temperature controlled at -5℃, 35 parts of micron-sized ice powder (particle size 50~200μm) are rapidly mixed into the dry powder of step S2 and mixed evenly; the cold powder is fed into a roller dry granulator, and a mechanical high pressure of 30MPa is applied without adding any liquid water. The micron-sized ice crystals are locally micro-melted under high pressure (re-icing phenomenon) to release a trace amount of interfacial water, which instantly wets and activates the sodium alginate powder to produce initial tack, and is forcibly pressed into primary particles with a diameter of 3~5mm; S4. Cryogenic liquid phase bidirectional in-situ crosslinking: Prepare a 30% calcium chloride aqueous solution in advance and add 0.1% hydroquinone. Use a refrigeration unit to keep the temperature constant at -20℃ as the cryogenic main crosslinking liquid. Put the primary particles pressed in step S3 directly into the cryogenic main crosslinking liquid. Driven by the osmotic pressure of high-concentration electrolyte, the unfrozen free water and calcium ions in the crosslinking liquid penetrate into the particle interior, so that sodium alginate undergoes crosslinking and solidification simultaneously while being hydrated in situ. Soak and react for 1 hour under low-speed stirring at 15r / min. S5. Vacuum freeze-drying and three-dimensional channel shaping: Take out the deeply cryogenically solidified particles, drain the surface free liquid, and lay them flat in the cold trap tray of the vacuum freeze dryer; freeze-dry continuously for 18 hours under the conditions of vacuum degree ≤10Pa and shelf temperature gradient controlled at -20℃ to gradually increase to 25℃, so that the internal solid ice is directly sublimated and removed, and the finished product is obtained.

[0051] Comparative Example 1: Compared with Example 1, the difference is that the dry pre-wetting and activation of the inorganic powder surface in step S1 is omitted, and the absolutely dry inorganic powder is directly mixed with the other components by dry method. The rest are the same.

[0052] Comparative Example 2: The difference from Example 1 is that micron-sized ice powder was not added in step S3, but all other steps are the same.

[0053] Comparative Example 3: Compared with Example 1, the difference is that in step S4, the temperature of the crosslinking liquid is set to room temperature (25°C) for conventional aqueous phase crosslinking, while the rest are the same.

[0054] Comparative Example 4: Compared with Example 1, the difference is that hydroquinone was not added to the cryogenic main crosslinking solution in step S4, but all other aspects are the same.

[0055] Comparative Example 5: Compared with Example 1, the difference is that no synthetic resin powder was added, and it was replaced with wood-based activated carbon powder in equal mass; otherwise, they are the same.

[0056] Test Example 1: Samples from Examples 1 to 5 and Comparative Examples 1 to 5 were degassed under vacuum at 120°C for 12 hours. Nitrogen adsorption-desorption tests were then conducted at 77 K (relative pressure range 0.01 to 0.995). Specific surface area was calculated using the BET method, the proportion of mesopore and macropore volumes was calculated using the BJH model, and the peak value of the average pore size distribution was calculated using NLDFT theory.

[0057] Table 1. Results of pore structure parameter determination for adsorbents in each example and comparative example.

[0058] refer to Figure 1 and Figure 2 Example 1 exhibits a larger specific surface area and total pore volume, with mesopores and macropores accounting for 65.23% of the volume. In Comparative Example 1, due to the lack of pre-activation of the inorganic powder surface, sodium alginate exhibits disordered agglomeration around the inorganic substrate, forming gel blocks that clog inherent pores, leading to a sharp reduction in specific surface area and total pore volume. Comparative Example 2, without the addition of micron-sized ice powder, relies solely on existing micropores, resulting in an extremely low proportion of mesopores and macropores, increasing mass transfer resistance. Comparative Example 3 undergoes crosslinking at room temperature; the melting of the ice powder removes the template support, and increased moisture causes excessive gel swelling, leading to pore collapse after drying. All examples maintain the solid ice crystal structure through cryogenic crosslinking, and vacuum freeze-drying allows the ice crystals to sublimate directly, forming three-dimensional interconnected channels in situ, effectively reducing physical mass transfer resistance.

[0059] Test Example 2: Fifty particles each from Examples 1 to 5 and Comparative Examples 1 to 5 were randomly selected and subjected to radial compressive strength tests. The average critical pressure at break was recorded. Another 50.0g sample was loaded into a fluidized bed and continuously purged with dry air at 0.5m / s for 120 minutes. The weight was then used to calculate the resistance to airflow impact abrasion.

[0060] Table 2. Test results of macroscopic mechanical and wear resistance properties of the adsorbents in each example and comparative example.

[0061] refer to Figure 3 Based on the data in Table 2, the compressive strengths of Examples 1 to 5 ranged from 48.7 N to 55.1 N, with abrasion rates all below 1.2%. Comparative Example 1 lacked surface pre-activation; the gel network and substrate were merely physically bound, making it easily peeled off under airflow impact, resulting in a compressive strength of only 18.3 N and a significantly increased abrasion rate. Comparative Example 3 rapidly gelled at room temperature, forming a shell that hindered internal cross-linking and failed to establish a complete pressure-bearing network. The examples, through cryogenic negative temperature and high-concentration electrolytes, suppressed instantaneous cross-linking and, combined with pre-placed crystal nuclei, achieved synchronous cross-linking network locking inside and outside the particles. Comparative Example 2, lacking a pore-forming agent, had a solid structure; although its compressive strength was high, it lacked porosity. The examples, while maintaining high porosity, also maintained mechanical stability against airflow impact.

[0062] Test Example 3: The particulate samples obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were placed in a closed static adsorption chamber saturated with styrene vapor at 25°C and kept at adsorption equilibrium for 24 hours. TGA-DSC testing was then performed, with nitrogen gas introduced and the temperature increased from 30°C to 250°C at a rate of 10°C / min. The mass residue at 200°C was extracted, and the exothermic peak enthalpy in the range of 100°C to 180°C was calculated by integration.

[0063] Table 3. High-temperature thermodynamics and anti-polymerization stability test results of the adsorbents in each example and comparative example.

[0064] refer to Figure 4 and Figure 5 Based on the data in Table 3, the examples effectively suppressed the polymerization reaction of styrene during high-temperature desorption. Comparative Example 4 showed an exothermic peak enthalpy of 214.7 J / g during heated desorption, with a residual rate of 38.6% at 200℃, indicating that a large amount of styrene polymerized and blocked the pores. The examples introduced hydroquinone as a polymerization inhibitor, which was locked at the gel network nodes during cryogenic crosslinking and could couple with free radicals to block the chain reaction during high-temperature desorption, significantly reducing the exothermic peak and resulting in residual rates below 5%. Comparative Example 2, due to its solid internal structure, experienced hindered styrene desorption mass transfer, prolonged local residence time, and exceeded the interception limit of the polymerization inhibitor, with the residual rate rising to 21.5%. The examples relied on a combination of multi-level pores and in-situ polymerization inhibitors to facilitate the smooth detachment of easily polymerizable components from the bed.

[0065] Test Example 4: Accurately weigh 2.0 g of pretreated particulate samples from each example and comparative example and pack them into a fixed-bed reaction tube. Introduce a mixture of ethyl acetate, toluene, and styrene (initial mass concentration 1000 mg / m³ each). 3 A mixture of gases was introduced at a flow rate of 200 mL / min and a temperature of 25 °C. The outlet gas concentration was monitored using a gas chromatograph, and the dynamic adsorption capacity was calculated with the breakthrough point being 5% of the inlet concentration for a single component.

[0066] Table 4. Dynamic breakthrough adsorption capacity test results of adsorbents for multi-component VOCs in each example and comparative example.

[0067] refer to Figure 6 and Figure 7Based on the data in Table 4, Comparative Example 5, without the addition of synthetic resin and relying solely on the microporous chassis, showed an adsorption capacity reduced to 102.4 mg / g when faced with larger styrene. In the quaternary system constructed in the examples, the hydrophobic framework and aromatic ring structure of the synthetic resin enabled targeted enrichment of styrene, allowing subsequent polar small molecules to smoothly enter the inorganic micropores, resulting in a balanced distribution of adsorption capacities among the components. In Comparative Example 2, due to the absence of a pore-forming template, the dense internal structure hindered molecular mass transfer, resulting in a styrene adsorption capacity of only 75.2 mg / g. The interconnected mesoporous and macroporous networks constructed using phase change pore-forming in the examples served as pathways for deep molecular mass transfer, reducing steric hindrance and achieving deep synergistic adsorption of multiple components.

[0068] Test Example 5: Weigh 3.0g of the particle samples from Examples 1 to 5 and Comparative Examples 1 to 5 and pack them into a fixed-bed reaction tube. Then, introduce toluene at a concentration of 1000mg / m³ at 25°C. 3 Simulated waste gas with a relative humidity of 80% was introduced until adsorption equilibrium was reached. Subsequently, nitrogen was introduced at 150°C for purging and desorption for 120 minutes. The adsorption and desorption process was repeated for 20 cycles, and the adsorption capacity of the first and last cycles was recorded and the retention rate was calculated.

[0069] Table 5. Test results of the regeneration performance of the adsorbents in each example and comparative example under high humidity alternating environment.

[0070] Reference Figure 8 and Figure 9 Based on the data in Table 5, Comparative Example 5, without the addition of synthetic resin, retained only 42.1% of its capacity after 20 cycles. The pure inorganic microporous network is susceptible to capillary condensation of water vapor, leading to irreversible blockage of adsorption sites by water molecules. Comparative Example 2, without the addition of pore-forming agent, retained 66.2% of its capacity. Due to the lack of large dehumidification channels, the retained moisture underwent phase transformation and expansion during high-temperature desorption, causing microscopic damage to the pore walls. The retention rates of all examples were above 91.8%. The hydrophobic microenvironment of the synthetic resin weakened the affinity adsorption of water molecules, and the remaining large, interconnected pores acted as a dehumidification buffer network, preventing the formation of continuous liquid blockages in the deeper layers. Simultaneously, the gel skeleton constructed by freeze-crosslinking exhibited good structural toughness, effectively mitigating adsorption passivation and attenuation under high-humidity alternating conditions.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art 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 appended claims and their equivalents.

Claims

1. A porous adsorbent with high adsorption efficiency and high desorption capacity, characterized in that, The porous adsorbent is made from raw materials comprising the following parts by weight: Silica powder: 15-25 parts; ZSM-5 type zeolite powder: 25-35 parts; Wood-based activated carbon powder: 20-25 parts; Synthetic resin powder: 10-20 parts; Sodium alginate powder: 10-15 parts.

2. The porous adsorbent with high adsorption efficiency and high desorption capacity according to claim 1, characterized in that, The porous adsorbent has a macroscopic morphology of particles with a diameter of 3 to 5 mm, and the interior of the porous adsorbent has micron-sized three-dimensional channels formed by the in-situ sublimation and removal of solid micron-sized ice crystals with a particle size of 50 to 200 μm.

3. The porous adsorbent with high adsorption efficiency and high desorption capacity according to any one of claims 1-2, characterized in that, The synthetic resin powder is a styrene-divinylbenzene copolymer that has undergone post-crosslinking and pore-expanding treatment. The preparation method includes the following steps: Styrene accounting for 60%~75% of the total mass of the oil phase, divinylbenzene accounting for 10%~20% of the total mass of the oil phase, toluene accounting for 15%~20% of the total mass of the oil phase, and benzoyl peroxide accounting for 1.0%~2.0% of the total mass of the aforementioned styrene and divinylbenzene monomers are mixed evenly to obtain the oil phase; In an aqueous phase containing a polyvinyl alcohol suspending dispersant, the oil phase is added at a mass ratio of (3~5):

1. After reacting at a constant temperature of 75~85℃ for 6~8 hours, the temperature is raised to 90~95℃ for 2~3 hours to obtain copolymer microspheres. The dried copolymer microspheres were placed in 1,2-dichloroethane at a mass-volume ratio of 1g:(4~6)mL and swollen for 12~24 hours. Then, anhydrous aluminum chloride of 20%~30% of the mass of the microspheres was added, and the mixture was refluxed at 80~85℃ for 8~12 hours. After the reaction was completed, the microspheres were washed, dried and pulverized.

4. The porous adsorbent with high adsorption efficiency and high desorption capacity according to any one of claims 1-3, characterized in that, The physicochemical parameters of the raw material meet the following conditions: The silica powder has a pore size distribution of 2~10nm and a particle size of 200~400 mesh; The ZSM-5 type zeolite powder has a silica-alumina ratio of 20~100 and a particle size of 300~500 mesh; The iodine adsorption value of the wood-based activated carbon powder is ≥800 mg / g, and the particle size is 200~300 mesh; The sodium alginate powder is a polymer composed of block copolymers of β-D-mannuronic acid and α-L-guluronic acid, with a molecular weight distribution between 10,000 and 600,000.

5. A method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Prepare silica gel powder, ZSM-5 zeolite powder and wood activated carbon powder according to the weight parts and put them into a fluidized bed. Spray the pre-activation liquid and pass hot air through for flash evaporation treatment to obtain absolutely dry inorganic powder. S2. The absolutely dry inorganic powder obtained in step S1, the synthetic resin powder prepared according to the stated weight parts, and the sodium alginate powder are mixed by pure physical mixing in an environment with a relative humidity of ≤40% to obtain a dry mixed powder. S3. Mix 20-50 parts by weight of micron-sized ice powder into the dry powder mixture of step S2 and mix evenly. Then apply a mechanical high pressure of 10-30 MPa without adding any liquid water to compress it into primary particles. S4. The primary particles pressed out in step S3 are directly put into the cryogenic main crosslinking liquid with the temperature controlled at -15℃~-20℃ for low-speed stirring and soaking reaction, so that sodium alginate undergoes crosslinking and curing simultaneously while being hydrated in situ. S5. Remove the cryogenically solidified granules and place them in a vacuum freeze dryer for continuous freeze drying, so that the internal solid ice can be directly sublimated and removed to obtain the finished product.

6. The method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity according to claim 5, characterized in that, In step S1: The pre-activation solution is an anhydrous calcium chloride solution in anhydrous ethanol with a mass fraction of 0.1% to 0.5%, or an anhydrous ferric chloride solution in anhydrous ethanol with a mass fraction of 0.1% to 0.5%. The amount of the pre-activation solution is 3% to 8% of the total mass of the inorganic powder; The flash evaporation conditions are as follows: hot air at 40-50°C is introduced for flash evaporation for 10-20 minutes to rapidly evaporate the ethanol solvent.

7. The method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity according to claim 5, characterized in that, In step S3: The particle size of the micron-sized ice powder is 50~200μm; The mixing of micron-sized ice powder and the pressing process are carried out under an ambient temperature controlled at -5℃ to 0℃; the diameter of the primary particles pressed is 3 to 5 mm.

8. The method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity according to claim 5, characterized in that, In step S4: The cryogenic main crosslinking solution is a calcium chloride aqueous solution with a mass fraction of 25%~30%, and hydroquinone with a mass fraction of 0.05%~0.2% is also added to the cryogenic main crosslinking solution; The conditions for the low-speed stirring soaking reaction are: soaking reaction for 1 to 2 hours at a stirring speed of 10 to 20 r / min.

9. The method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity according to claim 5, characterized in that, In step S5: The conditions for vacuum freeze drying are as follows: continuous freeze drying for 12 to 24 hours under conditions of vacuum degree ≤10Pa and shelf temperature gradient controlled at -20℃ gradually increasing to 25℃.

10. The method for preparing a porous adsorbent with high adsorption efficiency and high desorption capacity according to claim 5, characterized in that, In step S2: The process control parameters for the pure physical homogenization are: homogenization at a speed of 30-50 r / min for 30-60 minutes in an environment with a temperature of 20-25℃.

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