Mesoporous molecular sieve adsorbent as well as synthesis method and application thereof
By exchanging metal ions with MCM-41 mesoporous molecular sieves to form diverse adsorption sites, the problems of low efficiency and insufficient safety of traditional materials in the adsorption of multi-component gases are solved, realizing the efficient adsorption of various irritating gases and their application in hygiene products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-12
- Publication Date
- 2026-04-03
AI Technical Summary
Existing adsorption materials are inefficient at removing a variety of irritating gases with different physicochemical properties, especially in high humidity environments where they have low adsorption efficiency for large molecular gases. Furthermore, traditional materials lack safety and biocompatibility when used in hygiene products.
Metal ion exchange is performed using MCM-41 mesoporous molecular sieves, introducing metal ions such as Li+, K+, Mg2+, Ca2+, Fe2+, Zn2+, and Ag2+. Through surface acid-base interactions, complexation and chemical bonding, and enhanced van der Waals forces, diverse adsorption sites are formed. Combining the advantages of the mesoporous structure, efficient adsorption of gases of different sizes and polarities is achieved.
It provides high adsorption capacity and rate for gases such as ammonia, trimethylamine, hydrogen sulfide, isovaleric acid, methanethiol, nonanal, and decanal, and exhibits good stability under high humidity conditions, meeting the safety and biocompatibility requirements of hygiene products, and achieving broad-spectrum and efficient adsorption of multi-component odors.
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Figure CN121775802A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical materials technology, and more particularly to a mesoporous molecular sieve adsorbent, its synthesis method, and its application. Background Technology
[0002] In various scenarios such as biodegradation, industrial production, and daily life, a variety of gases with strong irritant and malodorous properties are produced, such as ammonia (NH3), trimethylamine ((CH3)3N), hydrogen sulfide (H2S), and isovaleric acid (C5H2O). 10 O2), methanethiol (CH4S), indole (C8H7N), nonanal (C9H 18 O), decanal (C 10 H 20 These gases, such as oxygen (O), not only cause sensory discomfort but are also corrosive or toxic, posing a threat to human health and quality of life. Especially in personal care products such as sanitary napkins and diapers, these gases are produced by microbial decomposition and metabolism, and direct contact with the skin can easily trigger allergies, dermatitis, and other problems. Therefore, their effective removal has become a key requirement for product upgrades in this field.
[0003] The efficient adsorption and removal of these gas molecules faces significant technical challenges, primarily due to the diversity of their physicochemical properties. Firstly, the molecular sizes and polarities vary greatly, ranging from small inorganic molecules (NH3, H2S) to organic amines, thiols, carboxylic acids, and large aldehydes, exhibiting significant differences in kinetic diameters, polarity, and acidity / basicity. Secondly, the adsorption mechanisms are complex, and a single mechanism is insufficient to efficiently adsorb all target substances. For example, while traditional activated carbon materials possess high specific surface areas, their adsorption capacity for small polar molecules (such as ammonia) and low-concentration odorous substances is limited, and their adsorption performance deteriorates sharply under high humidity conditions. Although zeolite molecular sieves possess regular microporous structures and ion exchange capabilities, their pore sizes are typically less than 2 nanometers, creating diffusion resistance for larger odorous molecules such as nonanal and decanal, resulting in low adsorption efficiency. Therefore, developing novel adsorption materials that combine a large specific surface area, suitable pore size to accommodate molecules of different sizes, and the ability to provide diverse adsorption sites through chemical modification has become an urgent need to solve the adsorption problem of these multi-component irritating odorous gases. Summary of the Invention
[0004] The MCM-41 mesoporous molecular sieve described in this invention, as a typical silicon-based nanomaterial, is characterized by its highly ordered two-dimensional hexagonal phase (P6mm) pore structure, tunable nanoscale pore size (2-10 nm), and high specific surface area (>1000 m²). 2It is known for its large pore volume ( / g). Its regular and uniformly sized mesoporous channels provide unobstructed diffusion paths and ample adsorption space for large molecules such as nonanal, decanal, and indole, fundamentally overcoming the bottleneck of microporous materials in adsorbing large molecules.
[0005] Pure silicon-based MCM-41 has a chemically inert surface and a weak adsorption capacity for polar gas molecules. This invention functionalizes it through metal ion exchange, incorporating Li... + K + Mg 2+ Ca 2+ Fe 2+ Zn 2+ Ag 2+ By introducing these into its framework or pore surface, the material is endowed with specific chemical adsorption active centers.
[0006] The adsorption principle and mechanism of this invention are mainly based on the following aspects: First, the surface acid-base interaction introduces metal cations (such as Li) + , K + Ca 2+ Mg 2+ As a Lewis acid site, it can strongly adsorb basic gas molecules with lone pairs of electrons, such as ammonia (NH3) and trimethylamine ((CH3)3N). Simultaneously, skeletal hydroxyl groups generated after ion exchange or basic sites introduced (such as K+) can also adsorb these molecules. + The relevant sites can adsorb acidic gases, such as hydrogen sulfide (H2S) and isovaleric acid; secondly, they can adsorb transition metal ions such as Fe. 2+ Zn 2+ Zn can form stable coordination bonds or undergo chemical reactions with sulfur- and nitrogen-containing compounds. 2+ Ag reacts with hydrogen sulfide (H2S) to form ZnS, and with methanethiol (CH3SH) to form Zn(CH3S)2, thus achieving irreversible or highly efficient chemisorption. + It has an extremely high affinity for sulfur-containing compounds and can catalyze their decomposition; finally, there is the enhanced van der Waals force and polarization. The highly dispersed metal ions change the electron cloud density on the pore surface, which enhances the van der Waals force between the adsorbent and gas molecules. In particular, for polar molecules such as aldehydes (nonanal, decanal), the presence of metal ions can induce them to generate stronger dipole moments, thereby improving the physical adsorption capacity through electrostatic interactions.
[0007] This invention balances the hydrophobicity of the framework with the number of exchangeable sites by adjusting the silicon-to-aluminum ratio (40-80); and optimizes the density and distribution of surface active sites by controlling the ion exchange rate (50%-80%), thus preventing pore blockage. Finally, the material, after calcination at a specific temperature (300℃-500℃) and atmosphere, can stabilize its structure and activate adsorption sites, forming a highly efficient composite adsorbent that integrates physical adsorption (mesoporous channels) and chemical adsorption (metal active sites).
[0008] This invention does not simply use the original MCM-41, but creatively combines the advantages of MCM-41's large pore size and high specific surface area with the specific chemical adsorption capacity of metal ions through multi-metal ion exchange and precise process control (exchange degree, silicon-aluminum ratio, calcination conditions), achieving "broad-spectrum" and efficient adsorption of a series of irritating odor gases from inorganic to organic and from small molecules to large molecules.
[0009] This invention successfully introduces mesoporous molecular sieve materials, originally widely used in industrial fields such as catalysis and macromolecular separation, into the field of hygiene products that come into direct contact with human skin. This requires materials to not only possess highly efficient adsorption properties but also meet stringent requirements such as safety, non-toxicity, and high biocompatibility. This invention achieves this technological breakthrough by selecting appropriate metal ions and synthesis processes.
[0010] Compared with traditional activated carbon and zeolite, the adsorbent provided by this invention exhibits comprehensive performance advantages in terms of adsorption capacity (especially for larger and polar molecules), adsorption rate (thanks to the mesoporous structure), and stability under high humidity conditions, providing a novel and efficient material solution for solving the problem of complex multi-component odor adsorption.
[0011] A method for synthesizing a mesoporous molecular sieve adsorbent, wherein the adsorbent is an MCM-41 mesoporous molecular sieve that has undergone metal ion exchange, followed by washing, drying, and calcination.
[0012] Optionally, the metal ion described in this invention is selected from Li. + K + Mg 2+ Ca 2+ Fe 2+ Zn 2+ Ag 2+ At least one of them.
[0013] Optionally, the ion exchange degree of the adsorbent obtained after ion exchange is 50% to 80%.
[0014] Optionally, the degree of ion exchange is selected from any value of 50%, 55%, 60%, 65%, 70%, 75%, or 80%, or a range between any two.
[0015] Optionally, the MCM-41 mesoporous molecular sieve has a silicon-to-aluminum ratio of 40 to 80, expressed as a molar ratio of SiO2 to Al2O3.
[0016] Optionally, the silicon-to-aluminum ratio is selected from any value or a range between any two of 40, 42, 45, 48, 50, 54, 56, 58, 60, 64, 66, 70, 72, 75, 78 or 80.
[0017] Optionally, the calcination temperature is 300℃~500℃, and the calcination is carried out in a preset atmosphere or vacuum; the preset atmosphere includes at least one of nitrogen, air or inert atmosphere; the calcination time is 2~24h.
[0018] Optionally, the roasting temperature is selected from any value of 300°C, 350°C, 400°C, 450°C or 500°C or a range between any two.
[0019] Optionally, the roasting time is selected from 2h, 5h, 7.5h, 10h, 12.5h, 15h, 17.5h, 20h, 22h or 24h.
[0020] Optionally, the adsorbent is used to adsorb a mixed gas from an air atmosphere, the mixed gas being derived from one, several, or all of the irritating odor gases such as ammonia, trimethylamine, hydrogen sulfide, isovaleric acid, methanethiol, indole, nonanal, and decanal produced by biodegradation, industrial production, and daily life.
[0021] Optionally, the adsorption test temperature in the adsorption includes liquid nitrogen temperature 77K, liquid argon temperature 87K, liquid oxygen temperature 90K, liquefied natural gas temperature 113K, ice temperature 273K, room temperature 298K, and human body temperature 309K.
[0022] Optionally, the adsorption pressure is 50~3000kPa.
[0023] Optionally, the adsorption pressure is selected from any value or a range between any two of 50 kPa, 100 kPa, 300 kPa, 500 kPa, 750 kPa, 1000 kPa, 1500 kPa, 1750 kPa, 2000 kPa, 2250 kPa, 2500 kPa, 2750 kPa, or 3000 kPa.
[0024] Compared with the prior art, the present invention has the following beneficial effects: 1) The adsorbent provided by the present invention has a greater adsorption capacity and higher adsorption efficiency for irritating odor gases including ammonia, trimethylamine, hydrogen sulfide, isovaleric acid, methanethiol, indole, nonanal, and decanal.
[0025] 2) The adsorbent provided by this invention is the first to successfully introduce mesoporous molecular sieve materials into the field of hygiene products that come into direct contact with human skin. This requires the material to not only have high adsorption performance, but also to meet stringent requirements such as safety, non-toxicity, and high biocompatibility. This invention achieves this technological breakthrough by selecting appropriate metal ions and synthesis processes.
[0026] 3) This invention provides a novel and efficient material solution for solving the problem of complex multi-component odor adsorption. Attached Figure Description
[0027] Figure 1 This is an XRD pattern of the product synthesized according to Example 1 of the present invention; Figure 2 This is a scanning electron microscope (SEM) image of the product synthesized according to Example 1 of the present invention; Figure 3 This is a single-component physical adsorption diagram of the product synthesized according to Example 1 of the present invention. Figure 4 This is a simulation diagram of the theoretical calculation framework of MCM-41 without ion exchange according to the present invention (Materialstudio). Figure 5 This is a physical image of the MCM-41(a) mesoporous molecular sieve; Figure 6 This is a physical image of adsorbent 1#, the product synthesized according to Example 2 of the present invention; Figure 7 This is a physical image of adsorbent 4#, the product synthesized according to Example 5 of the present invention; Figure 8 It is through the metal ion Mg 2+ A photograph of the exchanged Mg-MCM-41 mesoporous molecular sieve; Detailed Implementation
[0028] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.
[0029] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.
[0030] The adsorption process of the adsorbent of this invention for irritating odor gases such as ammonia, trimethylamine, hydrogen sulfide, isovaleric acid, methanethiol, indole, nonanal, and decanal is as follows: The adsorption column is a stainless steel tube (5 mL in volume). The calcined adsorbent (mass m) is loaded into the column, and the adsorption bed is purged with helium. The column is then placed in a coolant bath, water bath temperature, or human body temperature bath, and helium is added until the adsorption pressure is p. Then, mixtures of ammonia, trimethylamine, hydrogen sulfide, isovaleric acid, methanethiol, indole, nonanal, and decanal are prepared, each with a volume percentage of x, where 40% ≥ x ≥ 0.01%. The gas is passed through the adsorption bed at a flow rate L, and the permeated gas is continuously monitored using mass spectrometry. After the initial feed gas is introduced, the adsorbent bed becomes saturated after an adsorption time t, at which point the target component permeates through the bed. The saturated adsorption capacity of the adsorption bed is L·C·x·(t-t0) / m, where t0 is the dead time of the adsorbent bed and C is the concentration of the target gas.
[0031] Example 1
[0032] 10 g, 20 g, 30 g, 40 g, and 50 g of hexadecyltrimethylammonium bromide (DTAB) were added to 4.8 L of distilled water to form a homogeneous solution under stirring. 35 mL of sodium hydroxide (2 M) solution was added to this solution, and the mixture was stirred continuously at 80 °C for 5 minutes. Subsequently, 50 mL, 100 mL, 150 mL, 200 mL, and 250 mL of tetraethyl orthosilicate (TEOS) were added, and the reaction was continued at 80 °C for 2 h, 4 h, 6 h, 8 h, and 10 h, respectively. After the reaction was complete, the product was collected, washed with distilled water, and dried at 60 °C for 24 h. Finally, the obtained MCM-41 material was calcined at 550 °C for 5 h to completely remove the surfactant, yielding dried raw powders MCM-41-1, MCM-41-2, MCM-41-3, MCM-41-4, and MCM-41-5. Their silicon-to-aluminum ratio was determined using XRF.
[0033] Example 2
[0034] The MCM-41(a) mesoporous molecular sieve is the MCM-41 mesoporous molecular sieve. The MCM-41 mesoporous molecular sieve (with a silicon-to-aluminum ratio of SiO2 / Al2O3 = 40) is passed through a lithium-ion (Li... + The Li-MCM-41 mesoporous molecular sieve obtained after lithium ion exchange (60% lithium ion exchange capacity) was activated by calcination at 450℃ in air for 6 hours to obtain adsorbent 1# (corresponding to MCM-A). It was used to adsorb and separate ammonia / nitrogen mixtures with a concentration of 1000 ppm under ambient conditions (298 K and 101.3 kPa). The saturated adsorption capacity for ammonia was 3.8 mmol / g.
[0035] Example 3
[0036] MCM-41(a) mesoporous molecular sieve (selected with a silicon-to-aluminum ratio of SiO2 / Al2O3=60) was passed through a potassium ion exchange system (K+). + The K-MCM-41 mesoporous molecular sieve obtained after potassium ion exchange (75% potassium ion exchange rate) was activated by calcination at 500℃ under a nitrogen atmosphere for 4 hours to obtain adsorbent #2 (corresponding to MCM-B). Under human body temperature (309K) and normal pressure (101.3 kPa), it was used to adsorb and separate a trimethylamine / nitrogen mixture with a concentration of 500 ppm. The saturated adsorption capacity of trimethylamine was 2.9 mmol / g.
[0037] Example 4
[0038] MCM-41(a) mesoporous molecular sieve (selected with a silicon-to-aluminum ratio of SiO2 / Al2O3=50) was passed through calcium ion (Ca) 2+ The Ca-MCM-41 molecular sieve obtained after calcium ion exchange (calcium ion exchange degree of 70%) was activated by calcination at 400℃ in air for 8 hours to obtain adsorbent 3# (corresponding to MCM-C). It was used to adsorb and separate a hydrogen sulfide / nitrogen mixture with a concentration of 2000 ppm under ambient conditions (298 K and 101.3 kPa). The saturated adsorption capacity of hydrogen sulfide was 4.5 mmol / g.
[0039] Example 5
[0040] MCM-41(a) mesoporous molecular sieve (with a SiO2 / Al2O3 ratio of 80) was passed through a zinc ion exchanger (ZnO2 / Al2O3) filter. 2+ The Zn-MCM-41 molecular sieve obtained after zinc ion exchange (zinc ion exchange degree of 80%) was activated by calcination at 350℃ under vacuum for 10 hours to obtain adsorbent 4# (corresponding to MCM-D). It was used to adsorb and separate a 1000 ppm methanethiol / nitrogen mixture at room temperature (298 K) and atmospheric pressure (101.3 kPa). The saturated adsorption capacity of methanethiol was 3.2 mmol / g.
[0041] Example 6
[0042] MCM-41(a) mesoporous molecular sieve (selected with a silicon-to-aluminum ratio of SiO2 / Al2O3=70) was passed through a silver ion (Ag) ion exchanger. + The Ag-MCM-41 molecular sieve obtained after silver ion exchange (silver ion exchange degree of 65%) was activated by calcination at 300℃ under an argon atmosphere for 12 hours to obtain adsorbent 5# (corresponding to MCM-E). Under room temperature (298K) and atmospheric pressure (101.3 kPa), it was used to adsorb and separate a mixed malodorous gas (containing methanethiol and hydrogen sulfide) with a concentration of 800 ppm. The saturated adsorption capacity of methanethiol was 3.5 mmol / g.
[0043] Example 7
[0044] MCM-41(a) mesoporous molecular sieve (with a SiO2 / Al2O3 ratio of 45) was subjected to zinc and calcium ion composite exchange to obtain Zn / Ca-MCM-41 molecular sieve (total ion exchange degree of 75%). This Zn / Ca molecular sieve was then activated by calcination at 500℃ under a nitrogen atmosphere for 5 hours to obtain adsorbent #6 (corresponding to MCM-F). Under room temperature (298 K) and atmospheric pressure (101.3 kPa), a mixture of simulated isovaleric acid and hydrogen sulfide was adsorbed and separated. The saturated adsorption capacity of isovaleric acid was 2.5 mmol / g, and the saturated adsorption capacity of hydrogen sulfide was 4.0 mmol / g.
[0045] Example 8
[0046] MCM-41(a) mesoporous molecular sieve (selected with a silicon-to-aluminum ratio of SiO2 / Al2O3=55) was passed through a process involving iron ions (Fe). 2+ The Fe-MCM-41 molecular sieve obtained after ferric ion exchange (with an iron ion exchange rate of 55%) was activated by calcination at 450℃ under vacuum for 8 hours to obtain adsorbent #7 (corresponding to MCM-G). It was used to adsorb and separate an indole / nitrogen mixture with a concentration of 1000 ppm under ambient conditions (298 K and 101.3 kPa). The saturated adsorption capacity of indole was 2.1 mmol / g.
[0047] Comparative Example 1 Commercial coconut shell activated carbon was calcined at 300°C under a nitrogen atmosphere for 5 hours to obtain comparative adsorbent 1#.
[0048] Adsorption separation process: An ammonia / nitrogen mixture with a concentration of 1000 ppm was subjected to adsorption separation at room temperature (298 K) and atmospheric pressure (101.3 kPa). The saturated adsorption capacity of ammonia was 1.2 mmol / g.
[0049] Comparative Example 2 MCM-41(a) mesoporous molecular sieve (silicon-to-aluminum ratio of SiO2 / Al2O3=60) without any metal ion exchange was calcined at 450℃ in air for 6 hours to obtain comparative adsorbent 2#.
[0050] Adsorption separation process: An ammonia / nitrogen mixture with a concentration of 1000 ppm was subjected to adsorption separation at room temperature (298 K) and atmospheric pressure (101.3 kPa). The saturated adsorption capacity of ammonia was 0.7 mmol / g.
[0051] The adsorbent of Example 2 of this invention exhibited a saturated adsorption capacity of 3.8 mmol / g for ammonia under the same conditions; the commercial activated carbon of Comparative Example 1 had an adsorption capacity of 1.2 mmol / g; and the MCM-41(a) mesoporous molecular sieve of Comparative Example 2 had an adsorption capacity of 0.7 mmol / g. The comparison shows that the adsorption capacity of Example 2 is 3.2 times that of Comparative Example 1 and 5.4 times that of Comparative Example 2, indicating that the adsorbent of this invention, after metal ion exchange, has a significantly better adsorption capacity for irritating odor gases than traditional adsorbents and unmodified molecular sieves, demonstrating a remarkable deodorization effect.
[0052] The inventors have discovered that the adsorbent using the above-mentioned specific metal ion exchange is highly effective in adsorbing and removing irritating gases such as ammonia, trimethylamine, hydrogen sulfide, isovaleric acid, methanethiol, and indole. It has a large adsorption capacity and a fast adsorption rate, and can be used in personal care products such as sanitary napkins and diapers, as well as in the fields of industrial odor control and indoor air purification.
[0053] The above description is merely a few embodiments of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for synthesizing a mesoporous molecular sieve adsorbent, characterized in that, The adsorbent is an MCM-41 mesoporous molecular sieve adsorbent that has undergone metal ion exchange, followed by washing, drying, and calcination.
2. The method for synthesizing a mesoporous molecular sieve adsorbent according to claim 1, characterized in that, The metal ions include: Li + K + Mg 2+ Ca 2+ Fe 2+ Zn 2+ Ag 2+ At least one of them.
3. The method for synthesizing a mesoporous molecular sieve adsorbent according to claim 1, characterized in that, The ion exchange degree of the adsorbent obtained after metal ion exchange is 50% to 80%.
4. The method for synthesizing a mesoporous molecular sieve adsorbent according to claim 1, characterized in that, The silicon-aluminum ratio in the MCM-41 mesoporous molecular sieve is 40~80, expressed as the molar ratio of SiO2 to Al2O3.
5. The method for synthesizing a mesoporous molecular sieve adsorbent according to claim 1, characterized in that, The calcination temperature is between 300℃ and 500℃, and the calcination is carried out in a preset atmosphere or vacuum; the preset atmosphere includes one of nitrogen, air or inert gas; the calcination time is 2 to 24 hours.
6. A mesoporous molecular sieve adsorbent, characterized in that, The method described in any one of claims 1 to 5 is used for synthesis.
7. The application of the mesoporous molecular sieve adsorbent according to claim 6 to adsorb irritating odor gases from an air atmosphere, characterized in that, The pungent gas is at least one of ammonia, trimethylamine, hydrogen sulfide, isovaleric acid, methanethiol, indole, nonanal, and decanal.
8. The application according to claim 7, characterized in that, The adsorption test temperatures for the adsorbent during the adsorption process are: liquid nitrogen temperature 77K, liquid argon temperature 87K, liquid oxygen temperature 90K, liquefied natural gas temperature 113K, ice temperature 273K, room temperature 298K, or human body temperature 309K.
9. The application according to claim 7, characterized in that, The adsorption pressure of the adsorbent during the adsorption process is 50~3000kPa.