Preparation process of efficient VOCs adsorption and dehumidification composite rotating wheel

Abstract

The preparation process comprises the following steps: adding a template agent into a mixed solution of hydrochloric acid and water to obtain a molecular sieve template; mixing molecular sieve template water to prepare slurry, so as to obtain ordered mesoporous carbon; placing the mesoporous carbon in a strong oxidant solution to obtain ordered mesoporous carbon loaded with palladium single atoms; s3, mixing the mesoporous carbon obtained in S3 with a solvent, adding an amino-containing silane coupling agent, carrying out a reflux reaction, and washing to obtain a core-shell precursor; the preparation method comprises the following steps: dissolving an amphiphilic surfactant in an aqueous solution of a solvent and a base catalyst to obtain a core-shell material; the preparation method comprises the following steps: removing a template agent on a core-shell material, activating, adding a binder and mixing with water, dispersing and coating on a ceramic base material, carrying out gradient drying, preparing into a rotating wheel core, and placing in a rotating wheel, thereby realizing sequential function integration of VOCs preferential adsorption and deep dehumidification on single material particles.

Description

Technical Field

[0001] This invention relates to the field of composite rotor preparation, and more particularly to a preparation process of a composite rotor for high-efficiency VOCs adsorption and dehumidification. Background Technology

[0002] In the production process of lithium-ion batteries, electrolyte filling and formation are two crucial core processes. During this stage, the battery casing is filled with an electrolyte mainly composed of carbonate organic solvents (such as dimethyl carbonate and diethyl carbonate). However, in actual operation, some electrolyte solvents inevitably evaporate and escape through the workshop exhaust system, forming a special waste gas containing high-boiling-point, highly polar volatile organic compounds (VOCs) and a large amount of ambient moisture.

[0003] Traditional rotary adsorption purification technology faces severe challenges when dealing with complex waste gases. Currently, the mainstream solution in the industry is to use zeolite rotors for adsorption and concentration. The working principle utilizes the large specific surface area and hydrophilic properties of zeolite molecular sieves to simultaneously adsorb moisture and VOCs from the waste gas, followed by hot air desorption to obtain high-concentration waste gas for subsequent disposal. However, when such rotors are directly applied to lithium battery workshops, their inherent defects become apparent: the strong affinity of zeolite materials for water molecules causes them to preferentially adsorb large amounts of water, putting hydrophobic carbonate VOC molecules at a disadvantage in the adsorption competition and preventing their effective capture. These unremoved VOCs can penetrate the rotor, leading to excessive outlet concentrations. Summary of the Invention

[0004] This invention overcomes the shortcomings of the prior art and provides a preparation process for a composite rotor for high-efficiency VOCs adsorption and dehumidification.

[0005] To achieve the above objectives, the technical solution adopted by this invention is as follows: a preparation process for a high-efficiency VOCs adsorption and dehumidification composite rotor, comprising the following steps:

[0006] S1: Add the template agent to a mixed solution of hydrochloric acid and water, stir continuously, add silicon source material and stir at constant temperature, crystallize under high temperature and high pressure, dry, and calcine at high temperature to remove the template agent to obtain molecular sieve template;

[0007] S2: Mix molecular sieve template, carbon source material and catalyst with water to form a slurry, perform gradient drying, carbonization, remove molecular sieve template, wash and filter with water to obtain ordered mesoporous carbon.

[0008] S3: Place the mesoporous carbon in a strong oxidizing agent solution, reflux to oxidize, dry, place in a palladium-containing complex solution and stir, collect the solid by centrifugation, and pyrolyze to obtain ordered mesoporous carbon loaded with palladium single atoms;

[0009] S4: Mix the mesoporous carbon obtained in S3 with a solvent, add an amino-containing silane coupling agent, reflux the reaction, wash, and obtain the core-shell precursor;

[0010] S5: Dissolve the amphiphilic surfactant in an aqueous solution of solvent and base catalyst, add the core-shell precursor from S4, stir, add the silicon source solution that undergoes a condensation reaction with the core-shell precursor dropwise, keep stirring, replace the silicon source solution, continue the reaction, wash and dry to obtain the core-shell material.

[0011] S6: Remove the template agent from the core-shell material, activate it, add binder and water to mix, disperse and coat it on the ceramic substrate, gradient dry it to make a rotating core, and place it in the rotating wheel.

[0012] In a preferred embodiment of the present invention, in S1, the template agent is selected from one of Pluronic P123, Pluronic F-127 or Pluronic L121, the template agent mass is 3-5 parts, the hydrochloric acid acidity is 1-3M, the amount of hydrochloric acid is 100-140ml, the water mass is 20-40 parts, the continuous stirring temperature is 30-40℃, and the stirring speed is 200-400rpm.

[0013] In a preferred embodiment of the present invention, in S1, the silicon source material is selected from tetraethyl orthosilicate, sodium silicate, or silicon chloride, and the mass of the silicon source material added is 8-9 parts. The constant temperature and continuous stirring specifically means maintaining the stirring speed and temperature of the previous stirring and continuing to stir for 22-26 hours; the high temperature and high pressure crystallization is carried out in a high pressure reactor lined with polytetrafluoroethylene at 90-110°C for 47-49 hours; the drying temperature is 90-110°C for 10-14 hours; the high temperature calcination temperature is 540-560°C for 5-7 hours; and the molecular sieve template is SBA-15 molecular sieve template.

[0014] In a preferred embodiment of the present invention, in step S2, the carbon source is selected from sucrose, phenolic resin or sugar alcohol, and the catalyst is selected from concentrated sulfuric acid, phosphoric acid or toluenesulfonic acid. The mass ratio of molecular sieve template, carbon source, catalyst and water is 1:0.5-1.5:0.1-0.8:4-6. The gradient drying specifically involves drying at 90-110℃ for 5-7 hours, then heating to 150-170℃ and drying for 5-7 hours to pre-carbonize the sucrose.

[0015] In a preferred embodiment of the present invention, in S2, carbonization specifically involves heating to 800-1000°C at a rate of 1-3°C / min under a nitrogen atmosphere and carbonizing for 5-7 hours; removal of the molecular sieve template specifically involves using one of a sodium hydroxide solution, a potassium hydroxide solution, or a lithium hydroxide solution to corrode and remove the molecular sieve template; and water washing and filtration involves rinsing with water until neutral.

[0016] In a preferred embodiment of the present invention, in step S3, the strong oxidant solution is selected from concentrated nitric acid, hydrogen peroxide solution, or concentrated sulfuric acid solution, wherein the mass ratio of mesoporous carbon to concentrated nitric acid is 1:8-9; the reflux oxidation temperature is 80-100℃, and the time is 2-4h; the stirring speed is 150-300rpm, and the time is 22-26h, so that the complex solution is adsorbed on the carbon surface.

[0017] In a preferred embodiment of the present invention, in S3, the centrifugation speed is 200-300 rpm, and the pyrolysis is carried out under nitrogen atmosphere, with the temperature increased to 780-820℃ at 4-6℃ / min and held for 1-3 hours to form a Pd single-atom catalyst; the complex solution is specifically one of an aqueous solution containing chloropalladium acid and excess cyanoguanidine, a metal salt and sodium citrate solution, or a metal salt and melamine solution, and the ratio of mesoporous carbon to complex solution is 0.1:1-10.

[0018] In a preferred embodiment of the present invention, in step S4, the solvent is selected from anhydrous ethanol, isopropanol, or ethyl acetate, wherein the mass ratio of mesoporous carbon to solvent is 0.1-1:10; the amino-containing silane coupling agent is selected from 3-aminopropyltriethoxysilane, aminopropyltrimethoxysilane, or quaternary ammonium salt silane, wherein the ratio of solvent to amino-containing silane coupling agent is 100:0.1-2; the reflux reaction is carried out at a temperature of 76-80°C for 10-14 hours; and the washing is performed by rinsing with ethanol to remove unreacted silane coupling agent.

[0019] In a preferred embodiment of the present invention, in S5, the amphiphilic surfactant is selected from one of hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, or dodecyltrimethylammonium bromide, and the solvent is selected from one of anhydrous ethanol, ethyl acetate, or dimethyl sulfoxide.

[0020] The alkaline catalyst is selected from concentrated ammonia, sodium hydroxide, or potassium hydroxide, wherein the mass ratio of surfactant, solvent, and alkaline catalyst is 0.5-1.5:300:4; the ratio of core-shell precursor to aqueous solution is 0.2-0.4 parts of core-shell precursor per 100 ml of aqueous solution, and the stirring speed is 200-400 rpm; the silicon source solution is selected from tetraethyl orthosilicate, methyltriethoxysilane, or silicon tetrachloride, with a dropping rate of 0.3-0.7 mL / h and a reaction time of 5-7 h.

[0021] The silicon source solution is replaced with a mixed solution of tetraethyl orthosilicate and one of 3-aminopropyltriethoxysilane, methyltriethoxysilane, or silicon tetrachloride, with a mixing mass ratio of 4 parts tetraethyl orthosilicate and 0.1-1.0 parts of the other solution. The continuous reaction temperature is 30-50℃, and the reaction time is 20-28 hours.

[0022] In a preferred embodiment of the present invention, in step S6, removing the template agent from the core-shell material specifically involves refluxing the core-shell material in an ethanol solution of 0.1-0.3M hydrogen chloride for 10-14 hours; activation involves vacuum treating the core-shell material after template agent removal at a temperature of 100-200°C for 5-7 hours; the ratio of core-shell material, binder, and water is 80-90:10:5; dispersion involves stirring at a speed of 2500-3500 rpm for 0.5-1.5 hours; and the coating thickness is 380-420 μm.

[0023] The gradient drying process is as follows: initially dry under hot air at 70-90℃ for 20-40 minutes, then increase the temperature to 200-400℃ at a rate of 0.5-1.5℃ / min and hold for 50-70 minutes; then increase the temperature to 400-600℃ at a rate of 1.5-2.5℃ / min and hold for 110-130 minutes.

[0024] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0025] (1) This invention provides a process for preparing a composite rotor for high-efficiency VOCs adsorption and dehumidification. By using an ordered mesoporous carbon loaded with palladium single atoms as the catalytic core and an amino-modified gradient mesoporous silica as the hydrophilic shell, VOCs molecules can quickly reach the core through the mesopores of the shell and be strongly adsorbed by it. At the same time, the shell generates a preliminary physical hindrance to water molecules, thereby realizing the sequential integration of VOCs preferential adsorption and deep dehumidification on a single material particle. This allows the organic solvents in the exhaust gas to be captured and fixed in the core area first, greatly reducing the chance of them contacting the subsequent hydrophilic materials and undergoing corrosion reactions. Compared with the existing technology that uses physical partitioning, i.e., axial partitioned rotors or simple physical mixing of different adsorbents, this invention achieves precise division of labor and seamless connection of functions from the source of material design. It not only simplifies the overall structure of the rotor and reduces the complexity of manufacturing and maintenance, but also fundamentally avoids the interface separation problem that may occur due to the mismatch of the thermal expansion coefficients of different functional areas, thus improving the long-term operational reliability of the rotor.

[0026] (2) This invention provides a process for preparing a composite rotor for high-efficiency VOCs adsorption and dehumidification. By introducing a palladium single-atom catalyst and making it form a microsystem capable of generating energy and matter synergy with a mesoporous carbon support and a silica shell, when VOCs are catalytically degraded into CO2 and H2O in the core, the exothermic reaction will instantly increase the local temperature of the particles. This temperature increase reduces the viscosity of the moisture and accelerates its diffusion rate in the hydrophilic pores of the shell, thereby significantly improving the overall dehumidification efficiency. Compared with the existing rotors that require a large amount of heat energy input from the outside during the desorption stage and have independent energy consumption in the adsorption and desorption processes, this invention creatively transforms the decomposition process of harmful VOCs into an auxiliary energy source to drive the dehumidification function, realizing an intrinsic and self-driven energy synergy. This not only reduces the demand for additional heat energy and brings energy-saving effects, but also enables the rotor to have an adaptive and intelligent response characteristic when facing fluctuating VOCs concentration exhaust gas, exhibiting a more stable outlet air quality.

[0027] (3) This invention provides a process for preparing a composite rotor for high-efficiency VOCs adsorption and dehumidification. By catalytic degradation, it fundamentally eliminates the risk of high-boiling-point VOCs polymerizing and remaining at the adsorption sites, thereby solving the industry pain point of carbonization clogging the channels or hydrolysis generating acidic substances that corrode the zeolite skeleton. This allows the core adsorption and catalytic functions of the rotor to be maintained for a long time, avoiding the sharp decline in performance caused by the contamination of active sites. Compared with the current situation where existing dehumidification rotors have significantly shortened lifespan and need to be frequently replaced when facing the exhaust gas of lithium battery workshops, the rotor material provided by this invention exhibits excellent anti-poisoning ability and chemical stability, which further brings considerable economic benefits, greatly extends the service life and maintenance cycle of the rotor, reduces production losses caused by shutdown and replacement, and at the same time, its stable high performance ensures the dew point requirements of the downstream process, creating a continuous and reliable low-humidity environment for battery production, and significantly reducing the overall operating cost. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a three-dimensional structural diagram of a preferred embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0032] As shown in the figure, the preparation process of a high-efficiency VOCs adsorption and dehumidification composite rotor includes the following steps:

[0033] S1: Add the template agent to a mixed solution of hydrochloric acid and water, stir continuously, add silicon source material and stir at constant temperature, crystallize under high temperature and high pressure, dry, and calcine at high temperature to remove the template agent to obtain molecular sieve template;

[0034] S2: Mix molecular sieve template, carbon source material and catalyst with water to form a slurry, perform gradient drying, carbonization, remove molecular sieve template, wash and filter with water to obtain ordered mesoporous carbon.

[0035] S3: Place the mesoporous carbon in a strong oxidizing agent solution, reflux to oxidize, dry, place in a palladium-containing complex solution and stir, collect the solid by centrifugation, and pyrolyze to obtain ordered mesoporous carbon loaded with palladium single atoms;

[0036] S4: Mix the mesoporous carbon obtained in S3 with a solvent, add an amino-containing silane coupling agent, reflux the reaction, wash, and obtain the core-shell precursor;

[0037] S5: Dissolve the amphiphilic surfactant in an aqueous solution of solvent and base catalyst, add the core-shell precursor from S4, stir, add the silicon source solution that undergoes a condensation reaction with the core-shell precursor dropwise, keep stirring, replace the silicon source solution, continue the reaction, wash and dry to obtain the core-shell material.

[0038] S6: Remove the template agent from the core-shell material, activate it, add binder and water to mix, disperse and coat it on the ceramic substrate, gradient dry it to make a rotating core, and place it in the rotating wheel.

[0039] It should be noted that this invention consists of ordered mesoporous carbon loaded with palladium single-atom catalysts, which efficiently captures and catalytically degrades volatile organic compounds (VOCs). The mesoporous carbon itself possesses a large specific surface area and hydrophobic properties, giving it a natural strong adsorption preference for VOC molecules. The highly dispersed palladium single atoms act as "efficient decomposition stations" residing in the core, rapidly converting the adsorbed organic matter into harmless small molecules. The outer shell is a gradient mesoporous layer composed of amino-modified silica, which plays the role of a "smart screening and transport layer." Through controlled synthesis kinetics, the pore size of this shell exhibits a gradient change from the inside to the outside. This structure can perform preliminary screening of VOCs and water molecules based on differences in molecular size and polarity. VOC molecules, due to their characteristics, preferentially and rapidly pass through the outer shell channels to reach the core, while water molecules experience some diffusion hindrance in the outer shell layer.

[0040] Furthermore, the core and shell achieve deep functional synergy through interfacial chemical modification. When VOCs are catalytically degraded in the core, the released heat of reaction locally increases the particle temperature, which in turn promotes the diffusion and adsorption kinetics of water molecules that are blocked by the shell, thus achieving a synergistic effect of "heat of reaction-driven dehumidification". This intrinsic energy coupling generated by the material itself greatly optimizes the overall dehumidification efficiency.

[0041] Therefore, by constructing a gradient functionalized core-shell structure with core-in-core catalytic degradation, shell-layer intelligent screening, and interfacial energy synergy, this process spontaneously and orderly realizes a sequential workflow of "first adsorbing and eliminating VOCs, then deeply removing moisture" on a single material particle. This not only physically blocks the contact between corrosive organic matter and sensitive hydrophilic materials, but also eliminates the source of corrosion at its root through catalytic conversion. Thus, while ensuring efficient dehumidification performance, it endows the impeller with excellent durability and inherent corrosion resistance.

[0042] S1: Add the template agent to a mixed solution of hydrochloric acid and water, stir continuously, add silicon source material and stir at constant temperature, crystallize under high temperature and high pressure, dry, and calcine at high temperature to remove the template agent to obtain molecular sieve template;

[0043] In a preferred embodiment of the present invention, in S1, the template agent is selected from one of Pluronic P123, Pluronic F-127 or Pluronic L121, the template agent mass is 3-5 parts, the hydrochloric acid acidity is 1-3M, the amount of hydrochloric acid is 100-140ml, the water mass is 20-40 parts, the continuous stirring temperature is 30-40℃, and the stirring speed is 200-400rpm.

[0044] In a preferred embodiment of the present invention, in S1, the silicon source material is selected from tetraethyl orthosilicate, sodium silicate, or silicon chloride, and the mass of the silicon source material added is 8-9 parts. The constant temperature and continuous stirring specifically means maintaining the stirring speed and temperature of the previous stirring and continuing to stir for 22-26 hours; the high temperature and high pressure crystallization is carried out in a high pressure reactor lined with polytetrafluoroethylene at 90-110°C for 47-49 hours; the drying temperature is 90-110°C for 10-14 hours; the high temperature calcination temperature is 540-560°C for 5-7 hours; and the molecular sieve template is SBA-15 molecular sieve template.

[0045] It should be noted that in this step, Pluronic P123, a template agent, is selected as a triblock copolymer surfactant. When dissolved in an acidic aqueous solution, it self-assembles to form regular cylindrical micelles. After adding tetraethyl orthosilicate, a silicon source, the tetraethyl orthosilicate hydrolyzes under acidic conditions to generate silicic acid, which then condenses around the P123 micelles to form a silica / surfactant complex with micelles as templates. The high-temperature and high-pressure crystallization process promotes the perfection and stability of the silica framework. Through high-temperature calcination, the organic P123 template agent is completely burned off, leaving a silica framework with a regular hexagonal channel structure, namely the SBA-15 molecular sieve template. This template has uniform channel size and orderly arrangement, making it an ideal mold for replicating high-performance mesoporous carbon.

[0046] S2: Mix molecular sieve template, carbon source material and catalyst with water to form a slurry, perform gradient drying, carbonization, remove molecular sieve template, wash and filter with water to obtain ordered mesoporous carbon.

[0047] In a preferred embodiment of the present invention, in step S2, the carbon source is selected from sucrose, phenolic resin or sugar alcohol, and the catalyst is selected from concentrated sulfuric acid, phosphoric acid or toluenesulfonic acid. The mass ratio of molecular sieve template, carbon source, catalyst and water is 1:0.5-1.5:0.1-0.8:4-6. The gradient drying specifically involves drying at 90-110℃ for 5-7 hours, then heating to 150-170℃ and drying for 5-7 hours to pre-carbonize the sucrose.

[0048] In a preferred embodiment of the present invention, in S2, carbonization specifically involves heating to 800-1000°C at a rate of 1-3°C / min under a nitrogen atmosphere and carbonizing for 5-7 hours; removal of the molecular sieve template specifically involves using one of a sodium hydroxide solution, a potassium hydroxide solution, or a lithium hydroxide solution to corrode and remove the molecular sieve template; and water washing and filtration involves rinsing with water until neutral.

[0049] It should be noted that in this step, sucrose is used as a carbon source and impregnated into the pores of the SBA-15 template along with a concentrated sulfuric acid catalyst. The concentrated sulfuric acid acts as a catalyst to promote the dehydration and carbonization of the sucrose, and also as a crosslinking agent to help form a stable carbon skeleton. Through gradient drying, moisture is removed at a lower temperature, and then the sucrose is pre-carbonized at a higher temperature to form a preliminary carbon structure, preventing structural collapse during subsequent high-temperature treatment. High-temperature carbonization is carried out under an inert atmosphere to completely convert the sucrose into pure carbon. Finally, the silica template is removed by etching with a strong alkaline solution, and after washing with water until neutral, ordered mesoporous carbon with a structure opposite to that of the SBA-15 template (i.e., the pore walls of the template become the skeleton of the material) is obtained. The ordered mesoporous carbon inherits the regular pores of the template and has an extremely high specific surface area, providing abundant sites for the adsorption of a large number of VOC molecules.

[0050] S3: Place the mesoporous carbon in a strong oxidizing agent solution, reflux to oxidize, dry, place in a palladium-containing complex solution and stir, collect the solid by centrifugation, and pyrolyze to obtain ordered mesoporous carbon loaded with palladium single atoms;

[0051] In a preferred embodiment of the present invention, in step S3, the strong oxidant solution is selected from concentrated nitric acid, hydrogen peroxide solution, or concentrated sulfuric acid solution, wherein the mass ratio of mesoporous carbon to concentrated nitric acid is 1:8-9; the reflux oxidation temperature is 80-100℃, and the time is 2-4h; the stirring speed is 150-300rpm, and the time is 22-26h, so that the complex solution is adsorbed on the carbon surface.

[0052] In a preferred embodiment of the present invention, in S3, the centrifugation speed is 200-300 rpm, and the pyrolysis is carried out under nitrogen atmosphere, with the temperature increased to 780-820℃ at 4-6℃ / min and held for 1-3 hours to form a Pd single-atom catalyst; the complex solution is specifically one of an aqueous solution containing chloropalladium acid and excess cyanoguanidine, a metal salt and sodium citrate solution, or a metal salt and melamine solution, and the ratio of mesoporous carbon to complex solution is 0.1:1-10.

[0053] It should be noted that this step involves reflux oxidation with concentrated nitric acid to introduce oxygen-containing functional groups such as carboxyl and hydroxyl groups onto the framework of mesoporous carbon. These functional groups improve the hydrophilicity of the carbon material, facilitating subsequent solution treatment. Furthermore, they provide active sites for anchoring palladium. The oxidized mesoporous carbon is then immersed in a complex solution composed of chloropalladium acid and excess cyanoguanidine. The cyanoguanidine, acting as a strong ligand, forms a stable complex with palladium ions and is fixed to the functional groups of the mesoporous carbon through physical adsorption and coordination. After centrifugation, the mixture is subjected to controlled-temperature pyrolysis under an inert atmosphere. The pyrolysis process decomposes the organic ligands, while the palladium atoms are firmly fixed to defect sites on the carbon framework, forming a highly dispersed palladium single-atom catalyst. This single-atom morphology ensures that each palladium atom becomes an active center, maximizing the utilization of catalyst atoms and enabling efficient catalytic degradation of adsorbed VOCs.

[0054] S4: Mix the mesoporous carbon obtained in S3 with a solvent, add an amino-containing silane coupling agent, reflux the reaction, wash, and obtain the core-shell precursor;

[0055] In a preferred embodiment of the present invention, in step S4, the solvent is selected from anhydrous ethanol, isopropanol, or ethyl acetate, wherein the mass ratio of mesoporous carbon to solvent is 0.1-1:10; the amino-containing silane coupling agent is selected from 3-aminopropyltriethoxysilane, aminopropyltrimethoxysilane, or quaternary ammonium salt silane, wherein the ratio of solvent to amino-containing silane coupling agent is 100:0.1-2; the reflux reaction is carried out at a temperature of 76-80°C for 10-14 hours; and the washing is performed by rinsing with ethanol to remove unreacted silane coupling agent.

[0056] It should be noted that in this step, mesoporous carbon is dispersed in anhydrous ethanol, 3-aminopropyltriethoxysilane (APTES) is added, and a reflux reaction is carried out. The ethoxy group at one end of the APTES molecule hydrolyzes and condenses with the hydroxyl group on the surface of the mesoporous carbon to form a strong Si-OC covalent bond; the amino group at the other end faces outward, forming an amino-rich molecular layer on the core surface. This layer of amino functional groups becomes the "anchor point" for the subsequent growth of the silica shell, greatly enhancing the chemical bond between the core and shell and preventing the shell from falling off during use. This prepares a core-shell precursor that can be used for the next coating step. To coat the hydrophobic mesoporous carbon core loaded with catalyst with a hydrophilic shell, it is necessary to solve the problem of weak interfacial bonding between the two.

[0057] S5: Dissolve the amphiphilic surfactant in an aqueous solution of solvent and base catalyst, add the core-shell precursor from S4, stir, add the silicon source solution that undergoes a condensation reaction with the core-shell precursor dropwise, keep stirring, replace the silicon source solution, continue the reaction, wash and dry to obtain the core-shell material.

[0058] In a preferred embodiment of the present invention, in S5, the amphiphilic surfactant is selected from one of hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, or dodecyltrimethylammonium bromide, and the solvent is selected from one of anhydrous ethanol, ethyl acetate, or dimethyl sulfoxide.

[0059] The alkaline catalyst is selected from concentrated ammonia, sodium hydroxide, or potassium hydroxide, wherein the mass ratio of surfactant, solvent, and alkaline catalyst is 0.5-1.5:300:4; the ratio of core-shell precursor to aqueous solution is 0.2-0.4 parts of core-shell precursor per 100 ml of aqueous solution, and the stirring speed is 200-400 rpm; the silicon source solution is selected from tetraethyl orthosilicate, methyltriethoxysilane, or silicon tetrachloride, with a dropping rate of 0.3-0.7 mL / h and a reaction time of 5-7 h.

[0060] The silicon source solution is replaced with a mixed solution of tetraethyl orthosilicate and one of 3-aminopropyltriethoxysilane, methyltriethoxysilane or silicon tetrachloride, with a mixing mass ratio of 4 parts tetraethyl orthosilicate to 0.1-1.0 parts of other solutions. The continuous reaction temperature is 30-50℃ and the reaction time is 20-28h.

[0061] It should be noted that in this step, the surfactant CTAB is dissolved in an ethanol-water system containing ammonia. CTAB forms spherical micelles. After adding the precursor obtained from S4, tetraethyl orthosilicate (TEOS) is slowly added dropwise. The silicate ions generated by the hydrolysis of TEOS condense at the amino anchoring sites on the core surface under the catalysis of ammonia and grow around the CTAB micelles, forming a dense primary silica layer. This layer can effectively seal the core pores and prevent subsequent reagent intrusion. Subsequently, the reaction is continued with a mixed silicon source of TEOS and APTES. The addition of APTES introduces hydrophilic amino functional groups into the growing silica framework itself. At the same time, by controlling the reaction kinetics, the pore structure of the shell exhibits a gradient change from the inside to the outside: the inside is denser, preferentially sieving organic matter; the outside is looser, allowing molecules to pass through. The final core-shell material has a hydrophobic and catalytic mesoporous carbon core and a hydrophilic and gradient-porous silica shell.

[0062] S6: Remove the template agent from the core-shell material, activate it, add binder and water to mix, disperse and coat it on the ceramic substrate, gradient dry it to make a rotating core, and place it in the rotating wheel.

[0063] In a preferred embodiment of the present invention, in step S6, removing the template agent from the core-shell material specifically involves refluxing the core-shell material in an ethanol solution of 0.1-0.3M hydrogen chloride for 10-14 hours; activation involves vacuum treating the core-shell material after template agent removal at a temperature of 100-200°C for 5-7 hours; the ratio of core-shell material, binder, and water is 80-90:10:5; dispersion involves stirring at a speed of 2500-3500 rpm for 0.5-1.5 hours; and the coating thickness is 380-420 μm.

[0064] The gradient drying process is as follows: initially dry under hot air at 70-90℃ for 20-40 minutes, then increase the temperature to 200-400℃ at a rate of 0.5-1.5℃ / min and hold for 50-70 minutes; then increase the temperature to 400-600℃ at a rate of 1.5-2.5℃ / min and hold for 110-130 minutes.

[0065] It should be noted that this step involves reflux treatment of the core-shell material with a dilute hydrochloric acid ethanol solution to dissolve and remove the pore-forming template CTAB, thereby opening up the mesoporous channels of the shell and exposing the internal adsorption sites. Vacuum activation is then used to remove residual solvents and moisture from the pores. Subsequently, the activated core-shell material is mixed with the inorganic binder silica sol and water, and dispersed at high speed to form a uniform slurry. The silica sol will be converted into silica in the subsequent heat treatment, which firmly bonds the functional material particles to the ceramic fiber substrate. Gradient heating is used for drying and heat treatment. First, preliminary drying removes most of the moisture, then the binder is initially cured in the medium temperature stage, and finally the binder is completely cured in the high temperature stage and the material pores are further activated to ensure the structural stability of the rotor under high temperature desorption conditions. Finally, it is rolled into shape and packaged into the rotor housing.

[0066] Therefore, when waste gas containing DMC / DEC electrolyte organic matter and moisture passes through this rotor, the waste gas first comes into contact with the outer shell of the material. Because the outer shell has gradient mesopores and the core is strongly hydrophobic mesoporous carbon, it has an extremely high affinity for organic molecules. VOCs molecules will quickly pass through the pores of the outer shell, be efficiently adsorbed by the mesoporous carbon core and enriched around the palladium single-atom catalyst sites. Subsequently, triggered by the heat of adsorption or the hot air of desorption, the palladium catalyst catalytically degrades the VOCs molecules into small molecule products such as carbon dioxide and water. This process fundamentally eliminates the possibility of high-boiling-point VOCs polymerizing and remaining on the rotor, solving the corrosion source problem.

[0067] Meanwhile, water molecules behave differently. In the initial adsorption stage, due to the strong hydrophobicity of the core and the competitive adsorption of VOCs, most water molecules are temporarily "blocked" or only adsorbed on the hydrophilic amino sites of the shell. When the catalytic reaction of the core occurs, the generated by-product water and the heat released by the reaction will change the local chemical environment. The heat may further enhance the hydrophilicity of the shell, so that subsequent water molecules can be more efficiently adsorbed by the shell, achieving deep dehumidification. This sequential and functional synergy of "first adsorbing and converting VOCs, then adsorbing water" achieved through the material's own properties is the core principle of this invention to avoid rotor corrosion and achieve long-life and efficient operation.

[0068] Example 1:

[0069] Weigh 4 parts of Pluronic P123 template agent, add 130 mL of 2 M hydrochloric acid solution and 30 parts of deionized water, and place in a 35°C constant temperature water bath. Stir at 300 rpm until the template agent is completely dissolved and the solution is clear. Then, slowly add 8.6 parts of tetraethyl orthosilicate (TEOS) dropwise using a constant pressure dropping funnel. After the addition is complete, maintain the water temperature at 35°C and the stirring speed at 300 rpm, and continue the reaction for 24 hours. Transfer the resulting milky white mixture to a 200 mL polytetrafluoroethylene-lined high-pressure reactor and crystallize in a 100°C forced-air drying oven for 48 hours. After the reaction is complete, allow it to cool naturally to room temperature, filter, and wash the solid product with a large amount of deionized water until the filtrate is neutral. Place the filter cake in a 100°C oven to dry for 12 hours, then place the dried powder in a muffle furnace and program the temperature to 550°C at a rate of 1°C / min, and calcine at this temperature for 6 hours to completely remove the organic template agent. The final product was a white powdery SBA-15 molecular sieve template.

[0070] Weigh 1 part of the SBA-15 molecular sieve template prepared in step S1 above, 1.2 parts of sucrose, and 0.14 parts of concentrated sulfuric acid (as a catalyst), add 5 parts of deionized water, and sonicate to form a homogeneous slurry. Transfer the slurry to a petri dish, dry it in an oven at 100℃ for 6 hours, then raise the temperature to 160℃ and continue drying for 6 hours to fully melt the sucrose and preliminarily carbonize it. Transfer the resulting black solid powder to a tube furnace, raise the temperature to 900℃ at a rate of 2℃ / min under a nitrogen atmosphere, and carbonize it at this temperature for 6 hours. After naturally cooling to room temperature, place the carbonized product in a 2 M sodium hydroxide solution and stir at 80℃ for 12 hours to etch away the SBA-15 silicon template. After the reaction is complete, filter the product and wash the filter cake repeatedly with deionized water until the filtrate is neutral. Finally, dry the solid product at 100℃ for 12 hours to obtain black powdery ordered mesoporous carbon.

[0071] One part of the ordered mesoporous carbon obtained in step S2 was weighed and dispersed in 90 mL of concentrated nitric acid. It was refluxed at 90 °C for 3 hours, cooled, centrifuged, washed with deionized water until neutral, and dried at 100 °C to obtain oxidized mesoporous carbon with oxygen-containing functional groups on its surface. 0.5 parts of the oxidized mesoporous carbon were dispersed in 50 mL of an aqueous solution containing chloropalladium acid and excess cyanoguanidine (chloropalladium acid concentration 0.5 mmol / L). The solution was stirred at 250 rpm for 24 hours at room temperature to allow the palladium complex to be fully adsorbed onto the carbon surface. The solid was collected by centrifugation and heated to 800 °C at a programmed rate of 5 °C / min under a nitrogen atmosphere, and then pyrolyzed at this temperature for 2 hours. During pyrolysis, the cyanoguanidine ligands decomposed, and palladium atoms were anchored by defects in the carbon framework, forming a stable palladium single-atom catalyst.

[0072] Weigh 0.5 parts of the palladium single-atom catalyst obtained in step S3 and disperse it in 100 mL of anhydrous ethanol. Add 1.0 mL of 3-aminopropyltriethoxysilane (APTES) to this suspension and reflux at 78 °C for 12 hours. After the reaction is complete, centrifuge to separate the solid product and wash it three times with anhydrous ethanol to completely remove unreacted silane coupling agent. Dry the resulting solid at 60 °C to obtain a surface-aminated core-shell precursor.

[0073] 0.2 parts of hexadecyltrimethylammonium bromide (CTAB) were dissolved in a mixed solution consisting of 80 mL anhydrous ethanol, 20 mL deionized water, and 1 mL concentrated ammonia. The solution was sonicated until clear. 0.3 parts of the core-shell precursor obtained in step S4 were added to the mixed solution and mechanically stirred. 0.5 mL of tetraethyl orthosilicate (TEOS) was added dropwise at a rate of 0.5 mL / h using a micropump. After the addition was complete, the reaction was continued for 6 hours to form a dense primary silica layer. Subsequently, the silicon source was changed, and a mixed silicon source consisting of 4 mL of TEOS and 0.5 mL of APTES was added dropwise at a rate of 2 mL / h using a syringe pump. The reaction temperature was controlled at 40 °C, and the reaction was continued for 24 hours. After the reaction was completed, the product was collected by centrifugation, washed with ethanol, and dried at 60 °C to obtain the core-shell material precursor.

[0074] The core-shell material precursor obtained from S5 was placed in a 0.2M hydrochloric acid-ethanol solution and refluxed for 12 hours to remove the CTAB template agent. It was then washed with ethanol and vacuum activated at 150°C for 6 hours to obtain the final core-shell composite material. The core-shell material, silica sol (30% solid content), and deionized water were weighed at a mass ratio of 85:10:5 and placed in a high-speed disperser. The mixture was stirred at 3000 rpm for 60 minutes to prepare a homogeneous slurry. Using a doctor blade coater, the slurry was uniformly coated onto a ceramic fiber paper substrate, controlling the wet film thickness to 400 μm. The coated substrate was first pre-dried in hot air at 80°C for 30 minutes, and then placed in a muffle furnace for programmed temperature heat treatment: first, the temperature was increased to 300°C at 1°C / min and held for 60 minutes; then, it was increased to 500°C at 2°C / min and held for 120 minutes. After heat treatment, the coated substrate and corrugated paper are alternately stacked and rolled into a rotating core of specified size, and then encapsulated in the rotating housing to obtain the high-efficiency VOCs adsorption and dehumidification composite rotating wheel.

[0075] Experiment 1:

[0076] Example 1 was used as the control group. Several experimental groups were prepared by varying the pyrolysis temperature in S3 and the dropping rate of the silicon source solution in S5. Simulated exhaust gas with a composition similar to that of a lithium battery electrolyte filling workshop was prepared, containing a nitrogen / air mixture with a concentration of 500 ppm dimethyl carbonate and a relative humidity of 60% RH. Equal amounts of materials from the experimental and control groups were loaded into two adsorption tubes, respectively. Simulated exhaust gas was introduced under the same temperature, pressure, and space velocity. The VOCs concentration breakthrough time and moisture breakthrough time in the outlet gas flow were monitored online. Details are shown in Table 1.

[0077] Table 1

[0078] Pyrolysis temperature / °C Dropping rate / ml / h Concentration breakthrough time / min Moisture penetration time / min control group 800 0.5 83 75 Experimental Group 1 780 0.5 180 148 Experimental Group 2 820 0.5 182 152 Experimental Group 3 800 0.3 179 150 Experimental Group 4 800 0.7 181 151

[0079] As shown in Table 1, when the pyrolysis temperature is within an appropriate range, the palladium precursor can be fully reduced and stably anchored on the mesoporous carbon framework in single-atom form. This palladium single-atom catalyst exhibits the highest atom utilization rate, enabling extremely efficient catalytic degradation of adsorbed VOC molecules. In the breakthrough experiment, this highly efficient catalytic ability significantly prolongs the breakthrough time of VOC concentration. The VOCs adsorbed by the core are rapidly converted into small molecules of CO2 and H2O, thereby continuously releasing new adsorption sites. This allows the core to continuously capture organic solvents in the exhaust gas, greatly delaying their breakthrough time through the entire adsorption bed. Conversely, if improper temperature control leads to palladium atom aggregation into less active nanoparticles, the catalytic efficiency is greatly reduced, and VOCs will quickly saturate and break through, failing to achieve preferential and sustained adsorption.

[0080] When an extremely slow dropping rate is used, allowing the silicon source material to slowly hydrolyze and condense, a gradient mesoporous structure with gradually increasing pore size from the inside to the outside can be successfully constructed around the catalytic core. This structure creates differentiated mass transfer resistance between VOCs molecules and water molecules. The dense inner layer provides a dedicated channel for hydrophobic VOCs molecules to quickly reach the core, while the relatively loose but amino-modified hydrophilic outer layer produces a preliminary physical blocking effect on water molecule clusters. As a result, the water penetration time point is delayed and controlled after the VOCs penetration time point.

[0081] Ultimately, the long-lasting catalytic capability ensured by the pyrolysis temperature extends the VOCs penetration time. This, combined with the intelligent flow-guiding structure constructed through the dropping rate that delays and regulates the moisture penetration time, creates a synergistic effect of "integrated time-sequential VOCs preferential adsorption and deep dehumidification." The extended VOCs penetration time means that organic solvents are confined to the core area and treated efficiently to the maximum extent. Meanwhile, the delayed and orderly moisture penetration time ensures that the hydrophilic shell is in contact with the core-purified airflow with extremely low VOCs concentration for most of the operating time. This synergistic regulation of penetration time fundamentally blocks the path of direct contact between high-boiling-point, highly corrosive organic solvents and hydrophilic materials, thereby greatly improving the rotor's corrosion resistance and long-term operational stability, achieving the aforementioned beneficial effects of inherent safety and long-term durability.

[0082] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A preparation process for a high-efficiency VOCs adsorption and dehumidification composite rotor, characterized in that, Includes the following steps: S1: Add the template agent to a mixed solution of hydrochloric acid and water, stir continuously, add silicon source material and stir at constant temperature, crystallize under high temperature and high pressure, dry, and calcine at high temperature to remove the template agent to obtain molecular sieve template; S2: Mix molecular sieve template, carbon source material and catalyst with water to form a slurry, perform gradient drying, carbonization, remove molecular sieve template, wash and filter with water to obtain ordered mesoporous carbon. S3: Place the mesoporous carbon in a strong oxidizing agent solution, reflux to oxidize, dry, place in a palladium-containing complex solution and stir, collect the solid by centrifugation, and pyrolyze to obtain ordered mesoporous carbon loaded with palladium single atoms; S4: Mix the mesoporous carbon obtained in S3 with a solvent, add an amino-containing silane coupling agent, reflux the reaction, wash, and obtain the core-shell precursor; S5: Dissolve the amphiphilic surfactant in an aqueous solution of solvent and base catalyst, add the core-shell precursor from S4, stir, add the silicon source solution that undergoes a condensation reaction with the core-shell precursor dropwise, keep stirring, replace the silicon source solution, continue the reaction, wash and dry to obtain the core-shell material. S6: Remove the template agent from the core-shell material, activate it, add binder and water to mix, disperse and coat it on the ceramic substrate, gradient dry it to make a rotating core, and place it in the rotating wheel.

2. The preparation process of the high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In step S1, the template agent is selected from one of Pluronic P123, Pluronic F-127 or Pluronic L121, the template agent mass is 3-5 parts, the hydrochloric acid acidity is 1-3M, the amount of hydrochloric acid is 100-140ml, the water mass is 20-40 parts, the continuous stirring temperature is 30-40℃, and the stirring speed is 200-400rpm.

3. The preparation process of the high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In step S1, the silicon source material is selected from tetraethyl orthosilicate, sodium silicate, or silicon chloride, and the mass of the silicon source material added is 8-9 parts. The constant temperature and continuous stirring specifically means maintaining the stirring speed and temperature of the previous stirring and continuing to stir for 22-26 hours. The high temperature and high pressure crystallization is carried out in a high pressure reactor lined with polytetrafluoroethylene at 90-110°C for 47-49 hours. The drying temperature is 90-110°C for 10-14 hours, and the high temperature calcination temperature is 540-560°C for 5-7 hours. The molecular sieve template is SBA-15 molecular sieve template.

4. The preparation process of the high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In step S2, the carbon source is selected from sucrose, phenolic resin, or sugar alcohol, and the catalyst is selected from concentrated sulfuric acid, phosphoric acid, or toluenesulfonic acid. The mass ratio of molecular sieve template, carbon source, catalyst, and water is 1:0.5-1.5:0.1-0.8:4-6. The gradient drying process involves drying at 90-110℃ for 5-7 hours, followed by heating to 150-170℃ and drying for another 5-7 hours to pre-carbonize the sucrose.

5. The preparation process of the high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In S2, carbonization specifically involves heating to 800-1000℃ at a rate of 1-3℃ / min under nitrogen atmosphere and carbonizing for 5-7 hours; removal of the molecular sieve template specifically involves using one of sodium hydroxide solution, potassium hydroxide solution, or lithium hydroxide solution to corrode and remove the molecular sieve template; and water washing and filtration involves rinsing with water until neutral.

6. The preparation process of the high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In step S3, the strong oxidant solution is selected from concentrated nitric acid, hydrogen peroxide solution, or concentrated sulfuric acid solution, wherein the mass ratio of mesoporous carbon to concentrated nitric acid is 1:8-9; the reflux oxidation temperature is 80-100℃, and the time is 2-4h; the stirring speed is 150-300rpm, and the time is 22-26h, so that the complex solution is adsorbed on the carbon surface.

7. The preparation process of the high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In S3, the centrifugation speed is 200-300 rpm, and the pyrolysis is carried out under nitrogen atmosphere, with the temperature increased to 780-820℃ at 4-6℃ / min and held for 1-3 hours to form a Pd single-atom catalyst; the complex solution is specifically one of the following: an aqueous solution containing chloropalladium acid and excess cyanoguanidine, a solution of metal salt and sodium citrate, or a solution of metal salt and melamine, and the ratio of mesoporous carbon to complex solution is 0.1:1-10.

8. The preparation process of the high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In step S4, the solvent is selected from anhydrous ethanol, isopropanol, or ethyl acetate, wherein the mass ratio of mesoporous carbon to solvent is 0.1-1:10; the amino-containing silane coupling agent is selected from 3-aminopropyltriethoxysilane, aminopropyltrimethoxysilane, or quaternary ammonium salt silane, wherein the ratio of solvent to amino-containing silane coupling agent is 100:0.1-2; the reflux reaction is carried out at 76-80℃ for 10-14 hours; and the washing is performed by rinsing with ethanol to remove unreacted silane coupling agent.

9. The preparation process of a high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In S5, the amphiphilic surfactant is selected from one of hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, or dodecyltrimethylammonium bromide, and the solvent is selected from one of anhydrous ethanol, ethyl acetate, or dimethyl sulfoxide. The alkaline catalyst is selected from concentrated ammonia, sodium hydroxide, or potassium hydroxide, wherein the mass ratio of surfactant, solvent, and alkaline catalyst is 0.5-1.5:300:4; the ratio of core-shell precursor to aqueous solution is 0.2-0.4 parts of core-shell precursor per 100 ml of aqueous solution, and the stirring speed is 200-400 rpm; the silicon source solution is selected from tetraethyl orthosilicate, methyltriethoxysilane, or silicon tetrachloride, with a dropping rate of 0.3-0.7 mL / h and a reaction time of 5-7 h. The silicon source solution is replaced with a mixed solution of tetraethyl orthosilicate and one of 3-aminopropyltriethoxysilane, methyltriethoxysilane or silicon tetrachloride, with a mixing mass ratio of 4 parts tetraethyl orthosilicate to 0.1-1.0 parts of other solutions. The continuous reaction temperature is 30-50℃ and the reaction time is 20-28h.

10. The preparation process of a high-efficiency VOCs adsorption and dehumidification composite rotor according to claim 1, characterized in that: In step S6, removing the template agent from the core-shell material specifically involves refluxing the core-shell material in an ethanol solution of 0.1-0.3M hydrogen chloride for 10-14 hours; activation involves vacuum treating the core-shell material after template removal at 100-200°C for 5-7 hours; the ratio of core-shell material, binder, and water is 80-90:10:5; dispersion involves stirring at 2500-3500 rpm for 0.5-1.5 hours; and the coating thickness is 380-420 μm. Gradient drying specifically involves initial drying at 70-90°C for 20-40 minutes, increasing the temperature to 200-400°C at 0.5-1.5°C / min and holding for 50-70 minutes; then increasing the temperature to 400-600°C at 1.5-2.5°C / min and holding for 110-130 minutes.

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