Modified zeolite-based adsorption type composite moisture absorption material and preparation method thereof

Abstract

The invention discloses a modified zeolite-based adsorption type composite moisture absorption material and a preparation method thereof.The preparation method comprises the steps that zeolite is dispersed in an alkaline aqueous solution, selective etching is conducted, mesopores are generated, and a modified zeolite matrix of a multi-stage pore channel structure is obtained; s2, dispersing the modified zeolite matrix obtained in the step S1 into an organic solvent containing an organosilane coupling agent, and reacting for 2-12 hours at the temperature of 60-120 DEG C; s2, dipping the modified zeolite matrix treated in the step S2 in an aqueous solution containing a hydrophilic polymeric monomer, a cross-linking agent and an initiator or a water-alcohol mixed solution, reacting for 2-8 hours at the temperature of 40-80 DEG C in an inert atmosphere, or performing polymerization reaction under an ultraviolet irradiation condition to form a composite moisture absorption material with an organic-inorganic interpenetrating network structure; the introduction of the polymer network enhances the hydrophilicity and expansion capability of the material, and significantly improves the moisture absorption capacity and moisture absorption rate of the material.

Description

TECHNICAL FIELD

[0001] The present application relates to a modified zeolite-based adsorption type composite hygroscopic material, in particular to a modified zeolite-based adsorption type composite hygroscopic material and a preparation method thereof. BACKGROUND

[0002] In the field of traditional hygroscopic materials, silica gel, calcium chloride and other substances have been widely used, but they each have obvious limitations. The hygroscopic capacity of silica gel is limited and its performance significantly deteriorates in high-temperature environments, while salts such as calcium chloride have strong initial hygroscopic capacity but are prone to deliquescence or even solution leakage, which can cause potential harm to equipment and the environment. These materials lack durability and stability, making it difficult to meet the stringent requirements of precision instruments, electronic equipment, pharmaceutical storage and other high-end fields for humidity control. Therefore, developing a new type of adsorbent material that has high hygroscopic capacity, excellent stability and outstanding performance in a wide humidity range has become a key issue that needs to be addressed in this technical field.

[0003] Zeolites, as a kind of microporous crystalline material with regular pore structure, have great potential in the fields of adsorption and catalysis due to their unique shape-selective adsorption capacity and ion exchange properties. In particular, its molecular-sized pore structure can effectively capture water molecules through physical adsorption, and it has excellent thermal stability. However, natural zeolites or conventional synthetic zeolites also have inherent defects. Their hygroscopic performance is strongly dependent on the match between pore size and the kinetic diameter of water molecules, and desorption regeneration after adsorption saturation usually requires high temperatures, limiting its energy efficiency. More importantly, the adsorption capacity of a single zeolite is limited by its specific surface area and pore volume, and the hygroscopic kinetics in low humidity environments is often unsatisfactory. These factors make it difficult for pure zeolite materials to independently shoulder the heavy responsibility of high-efficiency hygroscopic materials. SUMMARY

[0004] The present application overcomes the shortcomings of the prior art and provides a modified zeolite-based adsorption type composite hygroscopic material and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a modified zeolite-based adsorption type composite hygroscopic material and a preparation method thereof, comprising the following steps:

[0006] S1: dispersing zeolite in an alkaline aqueous solution, performing selective etching to generate mesopores, and obtaining a modified zeolite substrate with a multi-level pore structure;

[0007] S2: dispersing the modified zeolite substrate obtained in S1 in an organic solvent containing an organosilane coupling agent, and reacting at a temperature of 60-120℃ for 2-12h;

[0008] S3: the modified zeolite matrix treated in S2 is immersed in an aqueous solution or a water-alcohol mixed solution containing a hydrophilic polymer monomer, a crosslinking agent and an initiator, and is reacted at a temperature of 40-80°C for 2-8h under an inert atmosphere or under ultraviolet light irradiation to form a composite moisture-absorbing material with an organic-inorganic interpenetrating network structure.

[0009] In a preferred embodiment of the present application, in S1, the zeolite has a Si / Al ratio of 1.5-4 and a particle size of 0.5-50μm; the aqueous alkaline solution has a pH of 10-14, and the alkali source is selected from one or more of sodium hydroxide, potassium hydroxide or ammonium hydroxide; and after the alkaline treatment, the zeolite matrix is subjected to washing, filtration and drying treatment, wherein the drying is performed in a vacuum oven at 80-120°C for 4-12h.

[0010] In a preferred embodiment of the present application, in S1, the aqueous alkaline solution has a pH of 12-13.5 and a temperature of 80-95°C, and the treatment time is 4-12h.

[0011] In a preferred embodiment of the present application, in S2, the organic solvent is selected from toluene, ethanol, isopropanol or a mixture thereof; the concentration of the organosilane coupling agent is 0.5-10%(w / v); and the reaction is performed under nitrogen.

[0012] After the reaction is completed, the modified zeolite matrix is subjected to washing, filtration and drying treatment, wherein the drying is performed in a vacuum oven at 60-80°C for 4-8h.

[0013] In a preferred embodiment of the present application, in S2, the organosilane coupling agent is vinyltrimethoxysilane, vinyltriethoxysilane, methacryloyloxypropyltrimethoxysilane, methacryloyloxypropyltriethoxysilane, acryloyloxypropyltrimethoxysilane or acryloyloxypropyltriethoxysilane.

[0014] The concentration of the organosilane coupling agent is 2-5%(w / v), the reaction temperature is 90-110°C, and the reaction time is 6-10h.

[0015] In a preferred embodiment of the present application, in S3, the hydrophilic polymer monomer is acrylic acid, acrylamide, hydroxyethyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, N-isopropyl acrylamide or a derivative thereof, and the concentration is 1-5mol / L.

[0016] The crosslinking agent is selected from N,N'-methylenebisacrylamide, ethylene glycol dimethacrylate, pentaerythritol tetraacrylate or a combination thereof, and the mol ratio of the crosslinking agent to the hydrophilic polymer monomer is 1:50-200.

[0017] The initiator is a thermal initiator or a photo initiator, and the concentration is 0.1%-2% of the total mol amount of the hydrophilic polymer monomers.

[0018] In a preferred embodiment of the present application, the thermal initiator in S3 is ammonium persulfate, potassium persulfate, azobisisobutyronitrile or benzoyl peroxide.

[0019] The wavelength of the ultraviolet light is 250-400nm, the light intensity is 10-100 mW / cm 2 , and the light exposure time is 10-60min.

[0020] In a preferred embodiment of the present application, the photo initiator in S3 is 2,2-dimethoxy-2-phenylacetophenone or 1-hydroxycyclohexyl phenyl ketone.

[0021] In a preferred embodiment of the present application, the inert atmosphere in S3 is nitrogen or argon, and after the polymerization reaction is completed, the composite material is subjected to washing, filtering and drying treatment, wherein the washing is repeatedly performed using water or an alcohol-water mixture until no monomer or initiator residue is detected in the washing liquid, and the drying is performed in a vacuum oven at 60-100℃ for 8-24h.

[0022] A modified zeolite-based adsorption type composite moisture absorption material comprises a modified zeolite base and a high moisture absorption polymer network,

[0023] The modified zeolite base is obtained by alkali treatment of zeolite, and the modified zeolite comprises a multi-level pore structure of micropores and mesopores, and the inner and outer surfaces of the modified zeolite base are pre-anchored with organic silane coupling agent residues having polymerizable unsaturated double bonds;

[0024] The mesopore volume ratio of the multi-level pore structure is 0.1cm 3 / g to 0.5cm 3 / g, and the average mesopore size is 2nm to 50nm.

[0025] The high moisture absorption polymer network is formed in the multi-level pore structure of the modified zeolite base by in-situ polymerization reaction, and the high moisture absorption polymer network and the organic silane coupling agent residues anchored on the surface of the modified zeolite base are connected by covalent bonds to form an organic-inorganic interpenetrating network structure.

[0026] The present application solves the defects in the background art, and has the following beneficial effects:

[0027] (1) The application provides a modified zeolite-based adsorption type composite hygroscopic material and a preparation method thereof, a multi-stage pore structure is generated by alkali treatment of zeolite, and surface functionalization is performed by using an organic silane coupling agent, and finally an organic-inorganic interpenetrating network structure is formed by in-situ polymerization, so that a micropore and mesopore synergistic multi-stage channel is formed in the zeolite matrix, the multi-stage channel not only provides more adsorption sites, but also optimizes the water molecule transmission path, and the introduction of the polymer network enhances the hydrophilicity and swelling capacity of the material, significantly improves the hygroscopic capacity and hygroscopic rate of the material, and enables the material to quickly reach hygroscopic equilibrium, compared with a traditional physical mixing material, the application avoids the problem of interface separation, and the hygroscopic efficiency is greatly improved; and the high-efficiency hygroscopic performance enables the material to exhibit rapid response capability in a dynamic humidity environment.

[0028] (2) The application provides a modified zeolite-based adsorption type composite hygroscopic material and a preparation method thereof, an interpenetrating network structure connected by covalent bonds is formed by anchoring and in-situ polymerization of an organic silane coupling agent, molecular-level combination of organic and inorganic phases is realized, the interface bonding force is effectively enhanced through covalent bond connection, and the peeling of the polymer network and the zeolite matrix under stress is prevented, so that the material exhibits excellent mechanical strength and can withstand a large external pressure without being easily damaged, compared with a simple impregnation and polymerization material, the application eliminates interface defects through chemical bonding, and the mechanical performance is obviously improved; and the high mechanical strength ensures the structural integrity of the material during processing and use, and expands the application range of the material in environments requiring bearing or wear resistance.

[0029] (3) The application provides a modified zeolite-based adsorption type composite hygroscopic material and a preparation method thereof, through the interpenetrating network structure of chemical anchoring, the polymer network is firmly fixed on the zeolite matrix through covalent bond connection, the stability of the covalent bond resists the repeated stress in the hygroscopic-desorption cycle, reduces the structural degradation, so that the material has excellent cycle stability, and the hygroscopic performance remains highly stable after multiple uses, compared with a physical mixing or non-covalent bonding material, the application fundamentally solves the interface failure problem, and the long-term durability is significantly improved; further, the long-term stability reduces the maintenance cost and the material replacement frequency, and enhances the reliability and economy in a continuous operation humidity control system. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, a brief introduction will be given to the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments described in the application, and other drawings can be obtained by those skilled in the art without creating laborious work;

[0031] Figure 1is a flow chart of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other manners different from those described herein, and therefore, the protective scope of the present application is not limited to the specific embodiments disclosed below.

[0034] As shown in Figure 1 A modified zeolite-based adsorption type composite moisture absorption material and a preparation method thereof, comprising the following steps:

[0035] S1: dispersing zeolite in an alkaline aqueous solution, performing selective etching to generate mesopores, and obtaining a modified zeolite substrate with a multi-level pore structure;

[0036] S2: dispersing the modified zeolite substrate obtained in S1 in an organic solvent containing an organosilane coupling agent, and reacting at a temperature of 60-120℃ for 2-12h;

[0037] S3: immersing the modified zeolite substrate treated in S2 in an aqueous solution or a water-alcohol mixed solution containing a hydrophilic polymer monomer, a crosslinking agent and an initiator, and reacting at a temperature of 40-80℃ for 2-8h under an inert atmosphere, or under ultraviolet light irradiation conditions to form a composite moisture absorption material with an organic-inorganic interpenetrating network structure.

[0038] S1: dispersing zeolite in an alkaline aqueous solution, performing selective etching to generate mesopores, and obtaining a modified zeolite substrate with a multi-level pore structure;

[0039] In a preferred embodiment of the present application, in S1, the silicon-aluminum ratio of the zeolite is 1.5-4, and the particle size is 0.5-50μm; the pH value of the alkaline aqueous solution is 10-14, and the alkali source is selected from one or more of sodium hydroxide, potassium hydroxide or ammonium hydroxide; after the alkali treatment, the zeolite substrate is subjected to washing, filtration and drying treatment, wherein the drying is performed in a vacuum oven at 80-120℃, and the drying time is 4-12h.

[0040] In a preferred embodiment of the present application, in S1, the pH of the alkaline aqueous solution is 12-13.5, the temperature is 80-95℃, and the time is 4-12h.

[0041] It should be noted that in this step, Y zeolite with a particle size of 15 μm and a silicon-aluminum ratio of 3.0 is selected, which is added to the previously prepared sodium hydroxide aqueous solution with a pH value of 12.8 at a concentration of 10% (w / v), and the alkali treatment is carried out at a temperature of 85°C for 7h. In this process, the sodium hydroxide mildly etches the silicon-oxygen bonds in the zeolite framework, introducing mesopores with a pore size of about 25 nm while retaining micropores, so that the mesopore volume reaches 0.28 cm 3 / g.

[0042] After the completion of the alkali treatment, the obtained suspension is cooled, and then the solid product is separated by suction filtration, and the solid product is repeatedly washed with a large amount of deionized water until the pH value of the washing liquid reaches 6.8-7.2, and finally, the washed zeolite is dried in a vacuum oven at 100°C for 12h to completely dehydrate and activate the surface silicon hydroxyl groups.

[0043] S2: dispersing the modified zeolite matrix obtained in S1 in an organic solvent containing an organic silane coupling agent, and reacting at a temperature of 60-120°C for 2-12h;

[0044] In a preferred embodiment of the present application, in the S2, the organic solvent is selected from toluene, ethanol, isopropanol or a mixture thereof; the concentration of the organic silane coupling agent is 0.5-10% (w / v); and the reaction is carried out under nitrogen.

[0045] After the reaction is completed, the modified zeolite matrix is subjected to washing, filtration and drying treatment, wherein the drying is carried out in a vacuum oven at 60-80°C for 4-8h.

[0046] In a preferred embodiment of the present application, in the S2, the organic silane coupling agent is vinyltrimethoxysilane, vinyltriethoxysilane, methacryloyloxypropyltrimethoxysilane, methacryloyloxypropyltriethoxysilane, acryloyloxypropyltrimethoxysilane or acryloyloxypropyltriethoxysilane.

[0047] The concentration of the organic silane coupling agent is 2-5% (w / v), the reaction temperature is 90-110°C, and the reaction time is 6-10h.

[0048] It should be noted that in this step, the modified zeolite matrix obtained in S1 is dispersed in an organic solvent containing an organic silane coupling agent, and the reaction is carried out under heating conditions to anchor the organic silane coupling agent residues on the inner and outer surfaces of the modified zeolite matrix.

[0049] The 15 g of modified zeolite matrix after S1 treatment and drying is added to 300 ml of anhydrous toluene, and ultrasonic dispersion is performed for 30 min to ensure uniform suspension. 6 ml of methacryloxypropyl triethoxysilane (MPS) is added as an organosilane coupling agent, and the concentration is about 2.0% (w / v). The reaction is heated under reflux at 110°C for 10 h under a nitrogen atmosphere, and continuous stirring is performed to promote the full reaction of the coupling agent with the surface silanol groups of the zeolite, so as to ensure that the MPS forms stable siloxane bonds with the zeolite framework through a hydrolysis condensation reaction, thereby firmly anchoring the polymerizable methacryloxy groups on the surface of the zeolite matrix.

[0050] After the reaction is completed, the suspension is cooled to room temperature, the solid product is collected by suction filtration, and the solid product is washed three times with 200 ml of anhydrous ethanol each time to remove unreacted coupling agents and residues. The solid product is dried in a vacuum oven at 75°C for 6 h to obtain a surface-functionalized modified zeolite matrix.

[0051] S3: The modified zeolite matrix treated in S2 is immersed in an aqueous solution or a water-alcohol mixed solution containing a hydrophilic polymerizable monomer, a crosslinking agent, and an initiator, and the reaction is carried out at a temperature of 40-80°C for 2-8 h under an inert atmosphere, or the polymerization reaction is carried out under ultraviolet light irradiation conditions, to form a composite moisture-absorbing material with an organic-inorganic interpenetrating network structure.

[0052] In a preferred embodiment of the present application, in S3, the hydrophilic polymerizable monomer is acrylic acid, acrylamide, hydroxyethyl methacrylate, 2-acrylamide-2-methylpropanesulfonic acid, N-isopropyl acrylamide, or a derivative thereof, and the concentration is 1-5 mol / L.

[0053] The crosslinking agent is selected from N,N'-methylenebisacrylamide, ethylene glycol dimethacrylate, pentaerythritol tetraacrylate, or a combination thereof, and the mol ratio of the crosslinking agent to the hydrophilic polymerizable monomer is 1:50-200.

[0054] The initiator is a thermal initiator or a photoinitiator, and the concentration is 0.1%-2% of the total mol amount of the hydrophilic polymerizable monomer.

[0055] In a preferred embodiment of the present application, in S3, a thermal initiator is used, and the thermal initiator is specifically ammonium persulfate, potassium persulfate, azobisisobutyronitrile, or benzoyl peroxide.

[0056] The wavelength of the ultraviolet light is 250-400 nm, the light intensity is 10-100 mW / cm 2 , and the light irradiation time is 10-60 min.

[0057] In a preferred embodiment of the present application, in S3, a photoinitiator is used, and the photoinitiator is specifically 2,2-dimethoxy-2-phenylphenylacetophenone or 1-hydroxycyclohexyl phenyl ketone.

[0058] In a preferred embodiment of the present application, in S3, the inert atmosphere is nitrogen or argon, and after the polymerization reaction is completed, the composite material is subjected to washing, filtering and drying treatment, wherein the washing is repeatedly performed using water or an alcohol-water mixture until no monomer or initiator residue is detected in the washing liquid, and the drying is performed in a vacuum oven at 60-100°C for 8-24h.

[0059] It should be noted that in this step, the modified zeolite matrix with the anchored residues of the organosilane coupling agent obtained in S2 is immersed in an aqueous solution or a water-alcohol mixed solution containing hydrophilic polymerization monomers, a crosslinking agent and an initiator, and a polymerization reaction is initiated under specific conditions, thereby forming an organic-inorganic interpenetrating network structure in which a high-hygroscopic polymer network is covalently connected to the modified zeolite matrix.

[0060] 5g of the functionalized zeolite matrix obtained in S2 is dispersed in 100ml of deionized water, and 12ml of acrylic acid is added as a hydrophilic polymerization monomer, with a concentration of 4mol / L, 0.15g of N, N'-methylenebisacrylamide is added as a crosslinking agent, with a mol ratio of 1:120 to the acrylic acid, and 0.05g of potassium persulfate is added as a thermal initiator, with a concentration of 0.2% of the total mol amount of the acrylic acid.

[0061] The mixture is dispersed under ultrasonic for 20min, high-purity nitrogen is introduced for 1h to completely remove oxygen, the reaction system is heated to 65°C under nitrogen protection, and stirring is continued at this temperature for 8h. In this process, the initiator decomposes to generate free radicals, which initiate the polymerization reaction of the acrylic acid monomer. At the same time, copolymerization and crosslinking occur between the acrylic acid monomer and the methacryloyloxy groups anchored on the surface of the functionalized zeolite and the crosslinking agent, forming a covalently connected interpenetrating network structure.

[0062] After the reaction is completed, the flask is cooled to room temperature, and the obtained composite material is taken out. The composite material is repeatedly washed five times using a 1:1 mixed solution of water and ethanol, with 100ml of washing liquid each time, and is subjected to suction filtration until no characteristic peaks of monomers or initiators are detected in the washing liquid. The washed composite material is dried in a vacuum oven at 90°C for 20h to completely remove moisture and residual solvents, and a final white modified zeolite-based adsorption-type composite hygroscopic material is obtained.

[0063] The scanning electron microscope (SEM) image of the obtained material shows that the polymer network uniformly fills and covers the inside and surface of the hierarchical pores of the zeolite matrix, and forms a dense combination with the zeolite framework without obvious interface defects. Fourier transform infrared spectroscopy (FTIR) analysis further confirms the presence of siloxane bonds and characteristic peaks of acrylic acid polymers, and the characteristic peaks of the siloxane bonds are at 1080cm -1Characteristic absorption of ester bond was observed nearby, which indicated the copolymerization reaction between the methacryloxy group and the acrylic monomer.

[0064] A modified zeolite-based adsorption type composite moisture absorption material, comprising a modified zeolite base and a superabsorbent polymer network,

[0065] The modified zeolite base is obtained by alkali treatment of zeolite, and the modified zeolite comprises a hierarchical pore structure of micropores and mesopores, and the inner and outer surfaces of the modified zeolite base are pre-anchored with organic silane coupling agent residues having polymerizable unsaturated double bonds;

[0066] The mesopore volume ratio of the hierarchical pore structure is 0.1 / 0.5 cm 3 / g, and the average mesopore size is 2-50 nm;

[0067] The superabsorbent polymer network is formed by in-situ polymerization inside and on the surface of the hierarchical pore structure of the modified zeolite base, and is connected to the organic silane coupling agent residues anchored on the surface of the modified zeolite base by covalent bonds to form an organic-inorganic interpenetrating network structure.

[0068] It should be noted that in the present application, the modified zeolite base is obtained by alkali treatment of zeolite, and has a hierarchical pore structure of micropores and mesopores inside and on the surface, and organic silane coupling agent residues having polymerizable unsaturated double bonds are pre-anchored on the inside and surface of the pores by chemical bonds.

[0069] The superabsorbent polymer network is formed by in-situ polymerization inside and on the surface of the hierarchical pore structure of the modified zeolite base, and is connected to the organic silane coupling agent residues anchored on the surface of the modified zeolite base by covalent bonds to form an organic-inorganic interpenetrating network structure.

[0070] In the above, the zeolite is a crystalline silico-aluminate mineral with a regular microporous structure, and the zeolite is Y-type zeolite with a silicon-aluminum ratio of 2.5-4.0 and an average particle size of 10-20 μm. When the silicon-aluminum ratio is too low, the resistance of the zeolite framework to alkaline environment is insufficient, and excessive damage occurs, leading to collapse of the microporous structure. When the silicon-aluminum ratio is too high, the framework stability is too high, and it is difficult to effectively generate sufficient mesopores, limiting the construction of the hierarchical pore structure. The particle size of the zeolite affects the overall bulk density, heat and mass transfer efficiency, and mechanical processing performance of the material.

[0071] During the preparation process, the zeolite is dispersed in an alkaline aqueous solution for reaction, and sodium hydroxide is used as the alkali source. A Y-type zeolite with a silicon-aluminum ratio of 3.0 and a particle size of 15 μm is dispersed in a 10% (w / v) concentration of a sodium hydroxide aqueous solution with a pH value of 12.5.

[0072] The alkaline treatment is carried out at a constant temperature of 80°C, and the reaction time is set to 6 h. Under this condition, the sodium hydroxide solution can selectively etch the silicon-oxygen tetrahedral bonds and the silicon-aluminum-oxygen bonds in the zeolite framework. Compared with the aluminum-oxygen tetrahedron, the silicon-oxygen tetrahedron is more easily eroded by the alkaline condition. This selective etching mechanism leads to the dissolution and reconstruction of part of the micropore wall, generating mesoporous structures in the internal and peripheral areas while retaining the core part of the original microporous structure. As a result, the microporous structure of the zeolite framework is retained, and the mesoporous structure is effectively constructed.

[0073] After this alkaline treatment, mesopores with a mesopore volume ratio of 0.25 cm 3 / g are formed inside the zeolite substrate, and the average pore size distribution of these mesopores is in the range of 10-30 nm. This hierarchical pore structure realizes the rapid transmission of water vapor molecules when they enter the deep area of the zeolite framework, while providing more abundant adsorption sites. After the alkaline treatment is completed, the obtained modified zeolite substrate is thoroughly washed, filtered, and dried. The washing operation uses high-purity deionized water for repeated rinsing until the pH value of the washing liquid reaches neutral, ensuring the removal of all residual alkaline substances and byproducts. Subsequently, suction filtration separation is performed, and finally, drying is carried out in a vacuum oven at 90°C for 10 h to completely remove the water and activate the surface silicon hydroxyl groups, providing a surface with high reactivity for subsequent surface functionalization reactions.

[0074] The organic silane coupling agent residue is then anchored on the inner and outer surfaces of the modified zeolite substrate. The organic silane coupling agent contains at least one silane group and one polymerizable unsaturated double bond. The silane group, such as a trimethoxysilane group, can form silicon hydroxyl groups after hydrolysis. These silicon hydroxyl groups can form stable covalent siloxane bonds with the existing silicon hydroxyl groups on the surface of the modified zeolite substrate through hydrolysis condensation reaction, thereby realizing the chemical anchoring of the organic silane coupling agent on the surface of the zeolite substrate.

[0075] The polymerizable unsaturated double bond, such as a vinyl or methacryloxy group, serves as an active site for subsequent polymerization reactions, used for copolymerization with hydrophilic polymer monomers. By selecting methacryloxypropyltrimethoxysilane as the organic silane coupling agent, the coupling agent has good hydrolysis activity and polymer compatibility. Its silane group can form stable bonding with the zeolite surface, and the methacryloxy group provides a highly active polymerizable site.

[0076] In the anchoring modification of the organic silane coupling agent, the modified zeolite substrate after the above-mentioned alkali treatment and drying is dispersed in anhydrous toluene solvent at a concentration of 5% (w / v), under stirring, 2.0% (w / v) of methacryloxypropyltrimethoxysilane is added, the modification reaction is carried out under nitrogen protection at 100°C under heating conditions, and the reaction time is set to 8h.

[0077] In the above-mentioned anchoring modification step, the purpose of nitrogen protection is to prevent the oxidation or unnecessary hydrolysis of methacryloxypropyltrimethoxysilane at high temperature, to ensure the specificity and efficiency of its reaction with the surface silanol groups of the zeolite, and to form a firm siloxane covalent bond through the hydrolysis and condensation reaction of the methacryloxypropyltrimethoxysilane molecules with the abundant surface silanol groups of the zeolite, which ensures the uniform distribution of the organic silane coupling agent on the inner and outer surfaces of the micropores and mesopores of the zeolite substrate, and permanently anchors the polymerizable methacryloxy group on the zeolite framework.

[0078] After the modification reaction is completed, the obtained functionalized zeolite substrate is washed with anhydrous ethanol for multiple times to completely remove the unreacted organic silane coupling agent and toluene solvent, then it is suction filtered and dried in a vacuum oven at 70°C for 6h to ensure that the surface active sites are not damaged and the material is completely dried.

[0079] Further, the high-hygroscopic polymer network is formed by in-situ grafting crosslinking polymerization of at least one hydrophilic polymer monomer, by selecting acrylic acid as the main hydrophilic polymer monomer, which has good hygroscopicity and polymerization activity, the carboxyl group in the acrylic acid can form hydrogen bonds with water molecules when absorbing moisture, and generate charged groups through dissociation, thereby enhancing the hygroscopic swelling capacity of the polymer network.

[0080] The polymer network is also connected to the organic silane coupling agent residues anchored on the surface of the modified zeolite substrate through grafting polymerization reaction, in which the carbon-carbon double bond in the acrylic acid monomer copolymerizes with the polymerizable unsaturated double bond in the organic silane coupling agent residues (such as methacryloxy group), and this copolymerization reaction is a key step to form the organic-inorganic covalently connected interpenetrating network structure.

[0081] The in-situ polymerization reaction is achieved by immersing the functionalized zeolite substrate with anchored organosilane coupling agent residues into a specific polymerization precursor solution and initiating polymerization under specific conditions. 10 g of the functionalized modified zeolite substrate is dispersed in a solution prepared by mixing deionized water and ethanol in a volume ratio of 1:1, which contains 3 mol / L of acrylic acid as a hydrophilic polymerization monomer. To build a stable three-dimensional cross-linked network, N, N'-methylene bisacrylamide is introduced as a cross-linking agent, and the mol ratio of N, N'-methylene bisacrylamide to acrylic acid is controlled at 1:100. N, N'-methylene bisacrylamide has two polymerizable acrylamide groups, which can connect different polymer chains during polymerization to form chemical cross-linking points, thereby giving the polymer network sufficient mechanical strength and structural stability to prevent dissolution or excessive deformation during moisture absorption expansion. To initiate the polymerization reaction, a thermal initiator ammonium persulfate is used, with a concentration of 0.5% of the total mol amount of acrylic acid. The initiator generates free radicals after thermal decomposition, thereby initiating the polymerization of acrylic acid monomers.

[0082] The in-situ polymerization reaction is carried out under a nitrogen-protected inert atmosphere, effectively inhibiting the polymerization inhibition of oxygen on free radical polymerization, ensuring the conversion rate and polymer yield of the polymerization reaction. The reaction temperature is 60°C, and the reaction time is 6h. In this way, ammonium persulfate can stably decompose to generate free radicals to initiate the chain growth polymerization of acrylic acid. At the same time, the copolymerization reaction between acrylic acid monomers, N, N'-methylene bisacrylamide cross-linking agent, and the methacryloyloxy groups anchored on the surface of the functionalized zeolite is carried out simultaneously, allowing the high-hygroscopic polymer network to grow inside the multi-level channels of the zeolite and be anchored on the zeolite framework in the form of a covalent bond.

[0083] After the polymerization reaction is completed, the resulting composite material needs to be subjected to repeated washing, filtering, and drying processes. The washing operation uses a mixture of water and ethanol for multiple rinses until no residual acrylic acid monomer or ammonium persulfate initiator is detected in the washing solution by high-performance liquid chromatography (HPLC), ensuring the removal of all unreacted components and byproducts. Finally, the material is dried in a vacuum oven at 80°C for 16h to obtain the final modified zeolite-based adsorption-type composite hygroscopic material, which is in the form of a white or light yellow powder.

[0084] It should also be noted that the zeolite with a silicon-aluminum ratio of 1.5-4 is from Tianjin Paixinnano Technology Co., Ltd.; the organic solvent in step S2 is from Sinopharm Chemical Reagent Co., Ltd.; and the silane coupling agent is from Wacker Chemical Company in Germany.

[0085] Example 1:

[0086] Take 100 g of Y zeolite with a silicon-aluminum ratio of 3.0 mol, add it to 1000 ml of a previously prepared sodium hydroxide aqueous solution with a pH of 12.8, which is obtained by dissolving 20 g of NaOH in 1000 ml of water; the mixture is subjected to magnetic stirring at 85°C for 7 h. After the reaction is completed, the system is cooled to room temperature, and the solid product is separated by suction filtration.

[0087] The solid product is repeatedly washed with 5000 ml of water, each time with about 500 ml, until the pH of the washing liquid reaches 7 by pH meter test, and the washed solid is dried in a vacuum oven at 100°C for 12 h to obtain a white powder of modified Y zeolite.

[0088] Take 50 g of the modified Y zeolite obtained in S1, add it to 1000 ml of anhydrous toluene, ultrasonically disperse for 30 min, add 20 ml of methacryloyloxypropyl trimethoxysilane (MPS) to the dispersion, pass high-purity nitrogen for 1 h, and then heat under reflux at 110°C for 10 h. Continuous stirring is maintained during the reaction, the system is cooled to room temperature, and the solid product is separated by suction filtration.

[0089] The solid product is washed three times with anhydrous ethanol, each time with 300 ml, to remove unreacted MPS and toluene, and the washed solid is dried in a vacuum oven at 75°C for 6 h to obtain a surface-functionalized modified Y zeolite, denoted as Y-MPS.

[0090] Disperse 10 g of the Y-MPS functionalized zeolite obtained in S2 in 200 ml of water, ultrasonically disperse for 15 min, and then sequentially add 24 ml of acrylic acid (AA, about 0.327 mol), 0.32 g of N, N'-methylenebisacrylamide (MBAA, about 0.002 mol, AA:MBAA mol ratio about 1:160), and 0.08 g of ammonium persulfate (APS, about 0.00035 mol, APS mol percentage relative to AA is 0.11%) to the dispersion.

[0091] After the mixture is thoroughly stirred, high-purity nitrogen is passed for 1 h to completely remove oxygen, the reaction system is heated to 65°C under nitrogen protection, and stirring is continued at this temperature for 8 h. After the reaction is completed, the flask is cooled to room temperature, and the resulting composite material is removed. The composite material is repeatedly washed with a 1:1 mixture of deionized water and ethanol, each time with 200 ml, a total of five times, and the washed composite material is dried in a vacuum oven at 90°C for 20 h to obtain the final modified zeolite-based adsorption type composite hygroscopic material, denoted as Y-PAA.

[0092] Performance test:

[0093] The prepared Y-PAA material was subjected to dynamic vapor sorption (DVS) test, mechanical strength test and cycle stability test, respectively.

[0094] The DVS test was carried out at 25℃ with the relative humidity (RH) gradually increasing from 0% to 90%, and the results showed that the equilibrium moisture absorption of the Y-PAA material at 90% RH was as high as 2.8 g water / g material, and the moisture absorption at 60% RH was 1.5 g water / g material. In terms of moisture absorption rate, the Y-PAA material reached more than 90% of its equilibrium moisture absorption within 30 min at 60% RH, showing excellent moisture absorption kinetics.

[0095] The mechanical strength test was carried out by uniaxial compression test, and the Y-PAA material was pressed into a disc with a diameter of 10 mm and a thickness of 2 mm. The compressive strength was measured to be 15.2 MPa.

[0096] The cycle stability test was carried out by 100 consecutive moisture absorption-desorption cycles, each cycle being 25℃, moisture absorption condition 90% RH / 4h, and desorption condition 100℃ / 2h. After 100 cycles, the moisture absorption performance (90% RH equilibrium moisture absorption) of the Y-PAA material remained above 98.5% of the initial value, showing excellent cycle stability.

[0097] Comparative Example 1:

[0098] Y-type zeolite with an average particle size of 15 μm and a silicon-aluminum ratio of 3.0 was selected, acrylic acid (AA), N, N'-methylenebisacrylamide (MBAA), ammonium persulfate (APS), and water were used. The monomer, crosslinking agent and initiator were mixed according to the ratio of the in-situ polymerization in Example 1, and a pure polyacrylic acid (PAA) hydrogel was prepared without adding zeolite. 24 ml of acrylic acid, 0.32 g of MBAA and 0.08 g of APS were dissolved in 200 ml of water, and nitrogen was passed for 1 h. Then the reaction was carried out at 65℃ for 8 h. The obtained gel was washed, dried and ground into fine powder. 10 g of the original Y-type zeolite powder and 5 g of the PAA powder prepared in step 1 were thoroughly mixed in a mortar to obtain a physical mixed composite material (denoted as Y / PAA-PM).

[0099] Performance test:

[0100] The Y / PAA-PM material was subjected to DVS test, mechanical strength test and cycle stability test, respectively.

[0101] The DVS test results show that the equilibrium moisture uptake of the Y / PAA-PM material is 1.8 g water / g material at 90% RH and 0.9 g water / g material at 60% RH; in terms of moisture uptake rate, the moisture uptake of the Y / PAA-PM material within 30 min at 60% RH reaches only 75% of the equilibrium moisture uptake, and the moisture uptake rate is significantly lower than that of the material of Example 1.

[0102] The mechanical strength test results show that the tablet compression strength of the Y / PAA-PM is 5.8 MPa.

[0103] In the cycle stability test, after 20 cycles of moisture absorption and desorption, the moisture absorption performance (equilibrium moisture uptake at 90% RH) of the Y / PAA-PM material has decreased to about 85% of the initial value, and the material has obvious pulverization and polymer shedding after multiple cycles, indicating that its structural stability is poor.

[0104] Comparative Example 2:

[0105] Select the modified Y zeolite after alkali treatment (obtained in step 1 of Example 1); acrylic acid (AA); N, N'-methylene bisacrylamide (MBAA); ammonium persulfate (APS); water for preparation.

[0106] Disperse 10 g of the modified Y zeolite after alkali treatment obtained in step 1 of Example 1 in 200 ml of deionized water, and then add 24 ml of acrylic acid, 0.32 g of MBAA and 0.08 g of APS to the dispersion. After 1 h of nitrogen blowing, react at 65°C for 8 h. After the reaction is completed, wash and dry according to step 3 of Example 1 to obtain a composite material, which is denoted as mY-PAA-IP. In this material, the polymer network is combined with the zeolite matrix through physical action and hydrogen bond, but lacks covalent bond connection.

[0107] Performance test:

[0108] The mY-PAA-IP material was subjected to DVS test, mechanical strength test and cycle stability test, respectively.

[0109] The DVS test results show that the equilibrium moisture uptake of the mY-PAA-IP material is 2.2 g water / g material at 90% RH and 1.2 g water / g material at 60% RH. In terms of moisture uptake rate, the moisture uptake of the mY-PAA-IP material within 30 min at 60% RH reaches 85% of the equilibrium moisture uptake.

[0110] The mechanical strength test results show that the tablet compression strength of the mY-PAA-IP is 9.5 MPa.

[0111] In the cycle stability test, after 50 cycles of moisture adsorption-desorption, the moisture adsorption performance (equilibrium moisture adsorption capacity at 90% RH) of the mY-PAA-IP material decreased to about 92% of the initial value, and a small amount of polymer was observed to be stripped from the zeolite surface.

[0112] Experiment 1:

[0113] According to the preparation methods of Example 1, Comparative Example 1 and Comparative Example 2, respectively, and the above method for performance testing, a comparison is made, as shown in Table 1.

[0114] Table 1

[0115] Performance index Example 1 Comparative Example 1 Comparative Example 2 90% RH equilibrium moisture uptake / g (H20) / g material 2.8 1.8 2.2 60% RH equilibrium moisture uptake / g (H20) / g material 1.5 0.9 1.2 60% RH equilibrium moisture absorption rate / percentage of moisture absorption amount reaching equilibrium in 30 minutes 95% 75% 85% Compressive strength / MPa 15.2 5.8 9.5 Moisture absorption amount retention rate after 100 cycles / % 99% 85% (after 20 cycles) 92% (after 50 cycles)

[0116] As can be seen from Table 1, compared with the physical mixing material of Comparative Example 1, the equilibrium moisture adsorption capacity of Y-PAA is increased by about 55% to 66%, the moisture adsorption rate is accelerated, and the mechanical strength is increased by about 160%. More importantly, Y-PAA can still maintain a moisture adsorption performance close to the initial value after 100 cycles of moisture adsorption-desorption, while the material of Comparative Example 1 has been greatly degraded in performance after only 20 cycles, and structural damage has occurred. This fully proves that the organic-inorganic interpenetrating network structure constructed by the present application is connected by covalent bonds, which fundamentally solves the problem of weak interfacial bonding force and poor structural stability of traditional physical mixing materials.

[0117] Compared with the simple impregnation polymer material of Comparative Example 2, the equilibrium moisture adsorption capacity of Y-PAA is increased by about 27% to 33%, the moisture adsorption rate is faster, and the mechanical strength is also increased by about 60%. In addition, the cycle stability of Y-PAA is also much better than that of Comparative Example 2. Even after 50 cycles, the material of Comparative Example 2 has shown a certain degree of performance degradation and polymer stripping, while Y-PAA still maintains high stability after 100 cycles. This indicates that simply constructing multiple channels by alkali treatment cannot completely solve the interfacial bonding problem between the polymer and the zeolite matrix. Only through chemical anchoring by organosilane coupling agent and subsequent in-situ grafting copolymerization, can a truly firm covalent bond connection be formed, thereby endowing the material with excellent long-term stability and mechanical strength.

[0118] As can be seen from the present application, by synergistically constructing multiple channels by alkali treatment, chemically anchoring by organosilane coupling agent, and forming an organic-inorganic interpenetrating network structure by in-situ grafting crosslinking polymerization, the moisture adsorption capacity, moisture adsorption rate, mechanical strength and cycle stability of the zeolite-based adsorption type composite moisture adsorption material can be significantly improved. The material prepared by the present application can cope with more complex and more severe application environments and exhibit more persistent performance, thereby expanding new possibilities for the application of high-performance moisture adsorption materials.

[0119] Experiment 2:

[0120] Take Example 1 as the experimental group, and change the silicon-aluminum ratio in step S1 and the concentration of the organosilane coupling agent in S2 in the experimental group respectively to prepare several control groups. Weigh the samples prepared in the experimental group and the control group, record the initial mass M0, and then place the samples in a constant temperature and humidity box at 25°C and 90% RH. After 4h, 8h and 24h, weigh the samples again and record them as M t Then calculate the moisture absorption amount of the sample, as shown in Table 2.

[0121] Table 2

[0122] Silicon aluminum ratio Concentration / % Initial mass (g) 4h moisture absorption amount (g / g) 8h moisture absorption amount (g / g) 24h moisture absorption amount (g / g) Experimental group 3.0 2% 1.001 1.45 2.10 2.75 Control group 1 2.0 2% 1.005 0.90 1.20 1.55 Control group 2 5.0 2% 0.998 0.60 0.85 1.10 Control group 3 3.0 0.5% 1.002 0.95 1.40 1.80 Control group 4 3.0 5% 0.995 0.80 1.25 1.65

[0123] As can be seen from Table 2, by comparing the data of the experimental group, control group 1 and control group 2 with a fixed MPS concentration of 2%, it can be seen that in the initial 4h of moisture absorption, the moisture absorption amount of the experimental group has reached 1.45 g / g, while that of control group 1 is only 0.90 g / g, and that of control group 2 is even lower at 0.60 g / g. This is because the silicon-aluminum ratio affects the etching effect of the base. The silicon-aluminum ratio of 3.0 in the experimental group is in the best range, so that the base treatment can successfully etch out abundant mesopores without damaging the overall integrity of the zeolite framework, forming a highway network that is conducive to the rapid diffusion of water molecules.

[0124] The silicon-aluminum ratio in control group 1 is too low, and the zeolite framework is not stable enough under alkaline conditions, leading to excessive etching and possible collapse of part of the microporous structure. Not only does it fail to effectively form mesopores, but it also reduces the original adsorption sites, causing the diffusion channel to be blocked and the moisture absorption rate to be slow. Conversely, the silicon-aluminum ratio in control group 2 is too high, and the framework is too stable to resist the etching effect of the base, making it difficult to generate enough mesopores. It mainly relies on the original micropores for diffusion, and the water molecule transmission path is long and the resistance is large, so the moisture absorption rate is the slowest.

[0125] Even at 24h near equilibrium, the final moisture absorption capacity of the experimental group is also much higher than that of control group 1 and control group 2, which indicates that the optimized hierarchical pore structure not only provides a high-speed diffusion path, but also creates more effective adsorption sites due to the large specific surface area of the mesopores, which together determine a higher equilibrium moisture absorption capacity.

[0126] On the other hand, the experimental data also highlights the role of the concentration of the organosilane coupling agent in step S2 in achieving high moisture absorption capacity. By comparing the data of the experimental group, control group 3 and control group 4 with a fixed silicon-aluminum ratio of 3.0, it can be seen that the experimental group reached a maximum equilibrium moisture absorption capacity of 2.75 g / g at 24h, while control group 3 and control group 4 reached 1.80 g / g and 1.65 g / g respectively, with a significant difference.

[0127] The fundamental reason for this phenomenon is that the coupling agent concentration directly affects the firmness and effectiveness of the connection between the high-hygroscopic polymer network and the modified zeolite matrix. For the control group 3, the excessively low concentration of 0.5% makes the polymerizable active sites anchored on the zeolite surface insufficient, and the polyacrylic acid network cannot be effectively "locked" on the zeolite skeleton through covalent bonds in the subsequent in-situ polymerization process.

[0128] A considerable part of the polymer is only physically blended, rather than chemically grafted, and this part of the physically adsorbed polymer is easily detached during washing and use, and cannot effectively contribute to the overall hygroscopic capacity, resulting in a lower measured hygroscopic amount. For the control group 4, an excessively high concentration of 5% may cause excessive accumulation or self-polymerization of the coupling agent molecules in the zeolite pores, which partially blocks the carefully constructed mesoporous channels, increasing the diffusion resistance of water molecules, which is evidenced by the fact that the hygroscopic amounts at 4h and 8h are lower than those of the experimental groups.

[0129] At the same time, excessive coupling agent may not effectively participate in interfacial connection, forming an invalid coating. Only the 2% optimal concentration used in the experimental group can form a uniform, dense and appropriate active site layer on the zeolite surface, ensuring that the polymer network can grow fully and form a firm covalent bond interpenetrating network with the inorganic skeleton, thereby efficiently and stably integrating the high-hygroscopic properties of polyacrylic acid into the composite material, and maximizing the hygroscopic capacity.

[0130] In summary, through comparative analysis of the control variables, the optimal silicon-aluminum ratio of S1 step is the core of achieving excellent hygroscopic rate, and the ideal multi-level channel structure laid the foundation for rapid water transmission. The optimal coupling agent concentration of S2 step is the key to achieving ultra-high hygroscopic capacity, which ensures that the function of the high-hygroscopic polymer network is maximized by forming a stable covalent bond connection.

[0131] Based on the ideal embodiments of the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the scope of the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing a modified zeolite-based adsorption-type composite moisture-absorbing material, characterized in that, Includes the following steps: S1: Zeolite is dispersed in an alkaline aqueous solution and selectively etched to generate mesopores, thereby obtaining a modified zeolite matrix with a multi-level pore structure; S2: Disperse the modified zeolite matrix obtained in S1 in an organic solvent containing an organosilane coupling agent and react at a temperature of 60-120℃ for 2-12 hours. S3: The modified zeolite matrix treated with S2 is impregnated in an aqueous solution or a water-alcohol mixture containing hydrophilic polymeric monomers, crosslinking agents and initiators, and reacted at 40-80℃ for 2-8 hours under an inert atmosphere, or under ultraviolet light irradiation, to form a composite moisture-absorbing material with an organic-inorganic interpenetrating network structure.

2. The preparation method of the modified zeolite-based adsorption-type composite moisture-absorbing material according to claim 1, characterized in that: In S1, the zeolite has a silica-alumina ratio of 1.5-4 and a particle size of 0.5-50 μm; the pH of the alkaline aqueous solution is 10-14, and the alkali source is selected from one or more of sodium hydroxide, potassium hydroxide, or ammonium hydroxide; after alkali treatment, the zeolite matrix is ​​washed, filtered, and dried, wherein the drying is carried out in a vacuum oven at 80-120℃ for 4-12 hours.

3. The preparation method of the modified zeolite-based adsorption-type composite moisture-absorbing material according to claim 1, characterized in that: In S1, the pH of the alkaline aqueous solution is 12-13.5, the temperature is 80-95℃, and the time is 4-12h.

4. The preparation method of the modified zeolite-based adsorption-type composite moisture-absorbing material according to claim 1, characterized in that: In step S2, the organic solvent is selected from toluene, ethanol, isopropanol, or mixtures thereof; the concentration of the organosilane coupling agent is 0.5-10% (w / v); the reaction is carried out under nitrogen atmosphere. After the reaction was completed, the modified zeolite matrix was washed, filtered and dried. The drying was carried out in a vacuum oven at 60-80℃ for 4-8 hours.

5. The preparation method of a modified zeolite-based adsorption-type composite moisture-absorbing material according to claim 1, characterized in that: In S2, the organosilane coupling agent is vinyltrimethoxysilane, vinyltriethoxysilane, methacryloyloxypropyltrimethoxysilane, methacryloyloxypropyltriethoxysilane, acryloyloxypropyltrimethoxysilane, or acryloyloxypropyltriethoxysilane. The concentration of the organosilane coupling agent is 2-5% (w / v), the reaction temperature is 90-110℃, and the reaction time is 6-10h.

6. The preparation method of the modified zeolite-based adsorption-type composite moisture-absorbing material according to claim 1, characterized in that: In S3, the hydrophilic polymeric monomer is acrylic acid, acrylamide, hydroxyethyl methacrylate, 2-acrylamide-2-methylpropanesulfonic acid, N-isopropylacrylamide or its derivatives, and the concentration is 1-5 mol / L; The crosslinking agent is selected from N,N'-methylenebisacrylamide, ethylene glycol dimethacrylate, pentaerythritol tetraacrylate or a combination thereof, and the molar ratio of the crosslinking agent to the hydrophilic polymeric monomer is 1:50-200; The initiator is a thermal initiator or a photoinitiator, with a concentration of 0.1%-2% of the total molar amount of the hydrophilic polymer monomers.

7. The preparation method of a modified zeolite-based adsorption-type composite moisture-absorbing material according to claim 6, characterized in that: In S3, a thermal initiator is used, specifically ammonium persulfate, potassium persulfate, azobisisobutyronitrile, or benzoyl peroxide. The ultraviolet light wavelength is 250-400nm, and the light intensity is 10-100mW / cm². 2 The illumination time is 10-60 minutes.

8. The preparation method of a modified zeolite-based adsorption-type composite moisture-absorbing material according to claim 6, characterized in that: In step S3, a photoinitiator is used, specifically 2,2-dimethoxy-2-phenylacetophenone or 1-hydroxycyclohexylphenyl ketone.

9. The preparation method of a modified zeolite-based adsorption-type composite moisture-absorbing material according to claim 1, characterized in that: In step S3, the inert atmosphere is nitrogen or argon. After the polymerization reaction is completed, the composite material is washed, filtered and dried. The washing is carried out repeatedly with water or an alcohol-water mixture until no monomer or initiator residue can be detected in the washing liquid. The drying is carried out in a vacuum oven at 60-100℃ for 8-24 hours.

10. A modified zeolite-based adsorption-type composite hygroscopic material, prepared according to any one of claims 1-9, comprising a modified zeolite matrix and a highly hygroscopic polymer network, characterized in that: The modified zeolite matrix is ​​obtained by alkali treatment of zeolite. The modified zeolite contains a multi-level channel structure of micropores and mesopores. The inner and outer surfaces of the modified zeolite matrix are pre-anchored with organosilane coupling agent residues with polymerizable unsaturated double bonds. The mesopore volume ratio of the multi-level channel structure is 0.1-0.5 cm³. 3 / g, with an average mesopore diameter of 2nm to 50nm; The highly hygroscopic polymer network is formed in the interior and surface of the multi-level porous structure of the modified zeolite matrix through in-situ polymerization. The highly hygroscopic polymer network is covalently connected to the organosilane coupling agent residues anchored on the surface of the modified zeolite matrix to form an organic-inorganic interpenetrating network structure.

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