A catalytic antibacterial composite material, its preparation method and application

Abstract

This application discloses a catalytic antibacterial composite material, its preparation method, and its applications, belonging to the field of functional inorganic-organic hybrid porous materials technology. The composite material comprises: an MCM-41@ZIF-8 core-shell composite material with a hierarchical porous structure; wherein the core is an MCM-41 mesoporous molecular sieve; and the shell is ZIF-8 nanocrystals in situ grown and loaded on the surface and within the pores of the MCM-41 mesoporous molecular sieve. This application solves the problem of excessive aggregation of ZIF-8 nanocrystals by forming a hierarchical porous core-shell structure, and achieves superior antibacterial ability than pure ZIF-8 nanocrystals through a synergistic effect generated by the specific structural combination of MCM-41 and ZIF-8. This material is applicable to polymer-based antibacterial materials and their products, and has great application potential in personal hygiene products, medical protective materials, and environmental purification filtration media.

Description

Technical Field

[0001] This application relates to a catalytic antibacterial composite material, its preparation method and application, belonging to the field of functional inorganic-organic hybrid porous materials technology. Background Technology

[0002] "Zeolitic imidazole ester framework material (ZIF-8), as a zinc-based metal-organic framework material, shows potential in the field of heterogeneous catalytic antibacterial applications due to its structural stability, high specific surface area, and unsaturated metal sites. Compared with mainstream traditional 'release-type' antibacterial materials (such as those that achieve antibacterial effects through the dissolution of metal ions like silver ions or the sustained release of active ingredients like quaternary ammonium salts), ZIF-8, based on a solid-phase surface catalytic mechanism, has the potential advantages of non-dissolution, long-lasting effect, and safety, and is of great significance in the development of next-generation hygiene and protective materials."

[0003] However, the practical application of ZIF-8 in polymer fiber materials faces a key technical obstacle: ZIF-8 is highly prone to agglomeration when used as a powder, and the agglomerated material is difficult to depolymerize and uniformly disperse in polymer melts or solutions. This not only leads to the embedding of catalytic active sites and a significant reduction in utilization, but also causes serious processing defects such as fiber breakage and decreased strength during spinning. Therefore, effectively overcoming the agglomeration problem of ZIF-8 and preparing ZIF-8-based functional materials with excellent dispersibility in polymer matrices is a prerequisite that must be solved to promote its large-scale application in polymer products such as fibers. Summary of the Invention

[0004] To address the problem of limited catalytic performance of ZIF-8 powder in polymer melts or solutions due to agglomeration issues in existing non-leaching catalytic antibacterial materials, this application provides a catalytic antibacterial composite material solution. This solution combines ZIF-8 with the mesoporous material MCM-41, using the mesoporous molecular sieve MCM-41 as the core carrier. ZIF-8 nanocrystals, a metal-organic framework material, are uniformly and orderly grown in situ on the surface and within the pores of MCM-41, forming a multi-level porous core-shell structure. This prevents excessive agglomeration of the ZIF-8 nanocrystals and improves the accessibility of active sites. This solution utilizes the large specific surface area and mesoporous structure of MCM-41 as an "adsorbent enricher," and the ZIF-8 nanocrystals grown on the surface and within the pores of MCM-41 provide catalytic active sites for in-situ killing of enriched microorganisms. It captures and concentrates microorganisms and their metabolites, achieving efficient, safe, and long-lasting antibacterial function through a synergistic mechanism of "adsorption enrichment-in-situ catalytic killing."

[0005] The technical solution adopted in this application is as follows: According to a first aspect of this application, a catalytic antibacterial composite material is provided, comprising: an MCM-41@ZIF-8 core-shell composite material having a hierarchical porous structure; The core is MCM-41 mesoporous molecular sieve; The shell is composed of ZIF-8 nanocrystals grown in situ on the surface and pores of the MCM-41 mesoporous molecular sieve.

[0006] Optionally, in the MCM-41@ZIF-8 core-shell composite material, the mass percentage of ZIF-8 nanocrystals is 20-60%; Optionally, the MCM-41@ZIF-8 core-shell composite material is a powder material with a particle size distribution of 0.3-3 μm.

[0007] Optionally, the MCM-41@ZIF-8 core-shell composite material has at least one of the following properties: The pH of the MCM-41@ZIF-8 core-shell composite material is neutral; No zinc ions or organic ligands were dissolved when the MCM-41@ZIF-8 core-shell composite material was immersed in water, weak acid solution and weak alkali solution. The specific surface area of ​​the MCM-41@ZIF-8 core-shell composite material is 900-1300 m² / g; The pore size distribution of the MCM-41@ZIF-8 core-shell composite material includes both micropores centered at 0.8 nm and mesopores centered at 3.8 nm.

[0008] According to a second aspect of this application, a method for preparing the aforementioned catalytic antibacterial composite material is provided, comprising: Provide a suspension A containing MCM-41 mesoporous molecular sieve, provide a solution B containing 2-methylimidazole, and provide a solution C containing zinc salt.

[0009] Under stirring conditions, solutions B and C are simultaneously and slowly added to suspension A to obtain a mixture. The mixture is then reacted under stirring conditions, and the reaction products are separated, washed, and dried to obtain the MCM-41@ZIF-8 core-shell composite material.

[0010] Optionally, the solvents in the suspension A, the solution B, and the solution C are independently selected from at least one of methanol, ethanol, and isopropanol.

[0011] Optionally, the zinc salt is selected from at least one of zinc nitrate, zinc chloride, and zinc sulfate.

[0012] Optionally, the molar ratio of MCM-41 mesoporous molecular sieve, 2-methylimidazole, and zinc salt in the mixture is 1:(50-70):(15-25).

[0013] Optionally, the reaction conditions include: a reaction temperature of 0-30°C and a reaction time of 4-16 hours.

[0014] Optionally, the MCM-41 mesoporous molecular sieve is synthesized by a hydrothermal method. The synthesis steps include: using hexadecyltrimethylammonium bromide as a template agent and tetraethyl orthosilicate as a silicon source, hydrothermal crystallization is carried out in an alkaline aqueous solution. After washing and drying, the crystallized product is calcined at 500-600℃ to remove the template agent, thereby obtaining the MCM-41 mesoporous molecular sieve.

[0015] According to a third aspect of this application, at least one of the aforementioned catalytic antibacterial composite materials or catalytic antibacterial composite materials obtained according to the aforementioned preparation method is provided as a non-leaching additive in polymer-based antibacterial materials and their products, wherein the catalytic antibacterial composite material is uniformly dispersed in a polymer matrix.

[0016] Optionally, the catalytic antibacterial composite material has a mass percentage of 0.5%-5.0% in the polymer matrix.

[0017] Optionally, the polymer-based antibacterial material and its products are antibacterial textile materials and textile products made from the antibacterial textile materials.

[0018] Optionally, the antibacterial textile material includes antibacterial masterbatch, antibacterial fiber, and nonwoven fabric; The nonwoven fabric is prepared from antibacterial masterbatch and / or antibacterial fibers.

[0019] Optionally, it includes one of hot-air nonwoven fabric, ES fiber nonwoven fabric, spunbond nonwoven fabric, spunlace nonwoven fabric or meltblown fabric.

[0020] Optionally, the textile products include children's diaper pads, adult diaper pads, sanitary napkins, medical dressings, air filters, water filters, or pet hygiene products.

[0021] The beneficial effects of this application include: (1) Highly effective and broad-spectrum antibacterial: Combining physical adsorption and chemical catalysis, it exhibits excellent and rapid killing effects on common pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, and Candida albicans.

[0022] (2) High safety: The material is extremely chemically stable and is neutral in general. No metal ions or organic components are leached out in the human body, thus avoiding the biotoxicity and allergy risks of traditional leaching antibacterial agents.

[0023] (3) Long-lasting and stable: The antibacterial effect does not depend on the consumable active ingredients. The material itself is stable, resistant to water, weak acids and weak alkalis, and the antibacterial effect is long-lasting and will not become ineffective due to the "depletion of active ingredients".

[0024] (4) Excellent application performance: The powder material has a moderate particle size and has little impact on the spinning process and fiber mechanical properties.

[0025] (5) Environmentally friendly: Common, low-toxic chemicals are used in the production process, and the materials themselves do not release harmful substances, which meets the requirements of green environmental protection. Attached Figure Description

[0026] Figure 1 X-ray diffraction (XRD) images of MCM-41, ZIF-8, and MCM-41@ZIF-8 of this application. Figure 2 This is a scanning electron microscope (SEM) image of MCM-41 in this application. Figure 3 The image is a scanning electron microscope (SEM) image of ZIF-8 in this application. Figure 4 The image is a scanning electron microscope (SEM) image of MCM-41@ZIF-8 in this application. Figure 5 The NH3 adsorption isotherm (87K) for MCM-41, ZIF-8, and MCM-41@ZIF-8 of this application. Detailed Implementation

[0027] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0028] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0029] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0030] According to one embodiment of this application, a catalytic antibacterial composite material includes: an MCM-41@ZIF-8 core-shell composite material having a hierarchical porous structure; The core is MCM-41 mesoporous molecular sieve; The shell consists of ZIF-8 nanocrystals grown in situ on the surface and within the pores of the MCM-41 mesoporous molecular sieve. The large specific surface area and mesoporous structure of MCM-41 can act as an "adsorbent and enricher" to capture and concentrate microorganisms and their metabolites. The ZIF-8 nanocrystals grown on the surface and within the pores of MCM-41 provide catalytically active sites for in-situ killing of the enriched microorganisms. The shell structure prevents excessive aggregation of ZIF-8 nanocrystals and improves the accessibility of the active sites.

[0031] In one embodiment, the mass percentage of ZIF-8 nanocrystals in the MCM-41@ZIF-8 core-shell composite material is 20% to 60%; preferably 30% to 50%.

[0032] In one embodiment, the MCM-41@ZIF-8 core-shell composite material is a powder material with a particle size distribution of 0.3-3 μm.

[0033] In one embodiment, the MCM-41@ZIF-8 core-shell composite material has at least one of the following properties: The pH of the MCM-41@ZIF-8 core-shell composite material is neutral; No zinc ions or organic ligands were dissolved when the MCM-41@ZIF-8 core-shell composite material was immersed in water, weak acid solution and weak alkali solution. The specific surface area of ​​the MCM-41@ZIF-8 core-shell composite material is 900-1300 m² / g; The pore size distribution of the MCM-41@ZIF-8 core-shell composite material includes both micropores centered at 0.8 nm and mesopores centered at 3.8 nm.

[0034] According to one embodiment of this application, the method for preparing the aforementioned catalytic antibacterial composite material includes: Provide a suspension A containing MCM-41 mesoporous molecular sieve, provide a solution B containing 2-methylimidazole, and provide a solution C containing zinc salt.

[0035] Under stirring conditions, solutions B and C are simultaneously and slowly added to suspension A to obtain a mixture. The mixture is then reacted under stirring conditions, and the reaction products are separated, washed, and dried to obtain the MCM-41@ZIF-8 core-shell composite material.

[0036] In one embodiment, the preparation method of the aforementioned catalytic antibacterial composite material includes: dispersing MCM-41 in methanol to obtain a uniformly dispersed suspension A (dispersion can be achieved by ultrasonic treatment for 0.5-1 hour). Dissolving 2-methylimidazole in methanol to obtain solution B. Dissolving zinc salt in methanol to obtain solution C. Simultaneously and slowly adding solutions B and C to suspension A under vigorous stirring. The mixture is continuously stirred and reacted at room temperature for 4-8 hours. After the reaction is complete, the product is centrifuged, washed 3-5 times with methanol, and dried in a vacuum drying oven at 60-80℃ for 12-24 hours to obtain the MCM-41@ZIF-8 core-shell composite material.

[0037] In one embodiment, the solvents in the suspension A, the solution B, and the solution C are independently selected from at least one of methanol, ethanol, and isopropanol.

[0038] In one embodiment, the zinc salt is selected from at least one of zinc nitrate, zinc chloride, and zinc sulfate.

[0039] The content of MCM-41 mesoporous molecular sieve in suspension A, the content of 2-methylimidazole in solution B, and the content of zinc salt in solution C are not strictly limited in this application, and can be selected as needed.

[0040] In one embodiment, the molar ratio of MCM-41 mesoporous molecular sieve, 2-methylimidazole, and zinc salt in the mixture is 1:(50-70):(15-25).

[0041] In one embodiment, the reaction conditions include a reaction temperature of 0-30°C and a reaction time of 4-16 hours.

[0042] In one embodiment, the MCM-41 mesoporous molecular sieve is synthesized by a hydrothermal method. The synthesis steps include: using hexadecyltrimethylammonium bromide as a template agent and tetraethyl orthosilicate as a silicon source, hydrothermal crystallization is carried out in an alkaline aqueous solution. After washing and drying, the crystallized product is calcined at 500-600°C to remove the template agent, thereby obtaining the MCM-41 mesoporous molecular sieve.

[0043] In one embodiment, the MCM-41 mesoporous molecular sieve is synthesized using a hydrothermal method. The synthesis steps include: using hexadecyltrimethylammonium bromide (CTAB) as a template agent, dissolving CTAB in an alkaline aqueous solution, stirring until dissolved, and then adding tetraethyl orthosilicate (TEOS) dropwise as a silicon source. The mixture is stirred continuously at 30-40°C for 2-4 hours. The resulting mixture is transferred to a polytetrafluoroethylene-lined stainless steel high-pressure reactor and hydrothermally crystallized at 100-120°C for 24-48 hours. After the reaction, the mixture is cooled to room temperature, filtered, and repeatedly washed with deionized water and ethanol. The resulting solid is dried at 80°C for 6-12 hours, and finally calcined in a muffle furnace at 500-600°C for 5-6 hours (heating rate 1°C / min) to remove the template agent, yielding the pure silicon MCM-41 mesoporous molecular sieve.

[0044] Mesoporous molecular sieve MCM-41 possesses a highly ordered hexagonal pore structure, a large specific surface area (typically greater than 1000 m² / g), and adjustable pore size (2-10 nm). Its abundant silanol groups on the surface give it strong physical adsorption capacity for microorganisms and their metabolites, but it lacks significant catalytic antibacterial activity. In contrast, ZIF-8, a metal-organic framework material formed by the coordination of zinc ions and 2-methylimidazolium, exhibits a sodalite topology. ZIF-8 possesses excellent chemical stability (especially in water), abundant microporous structure, and a high specific surface area. In the technical solution of this application, the Zn-N sites in ZIF-8 may catalyze the generation of reactive oxygen species (such as ·OH) under humid conditions, or disrupt the integrity of microbial cell membranes through surface coordination, thereby achieving non-leaching catalytic sterilization.

[0045] According to one embodiment of this application, at least one of the aforementioned catalytic antibacterial composite material or the catalytic antibacterial composite material obtained according to the aforementioned preparation method is used as a non-leaching additive in polymer-based antibacterial materials and their products, wherein the catalytic antibacterial composite material is uniformly dispersed in the polymer matrix.

[0046] In one embodiment, the catalytic antibacterial composite material has a mass percentage of 0.5%-5.0% in the polymer matrix.

[0047] In one embodiment, the polymer-based antimicrobial material and its products are antimicrobial textile materials and textile products made from the antimicrobial textile materials.

[0048] In one embodiment, the antimicrobial textile material includes antimicrobial masterbatch, antimicrobial fiber, and nonwoven fabric; The nonwoven fabric is prepared from antibacterial masterbatch and / or antibacterial fibers. Specifically, antibacterial textile materials are dispersed or mixed into chemical fiber spinning melt or spinning solution, and antibacterial fibers with antibacterial functions are prepared through a spinning process.

[0049] In one embodiment, it includes one of hot air nonwoven fabric, ES fiber nonwoven fabric, spunbond nonwoven fabric, spunlace nonwoven fabric or meltblown fabric.

[0050] In one embodiment, the textile products include children's diapers, adult diapers, sanitary napkins, medical dressings, air filters, water filters, or pet hygiene products.

[0051] The antibacterial principle of the catalytic antibacterial composite material or the polymer-based antibacterial material and its products based on the present application is as follows: This antibacterial agent, a non-leaching catalytic antibacterial agent, exerts its antibacterial effect through a synergistic "adsorption-catalysis" mechanism. Specifically, the mesoporous structure of MCM-41 adsorbs and enriches microorganisms and their metabolites (accumulating free bacteria, fungi, and their released toxins and metabolites from solution or air on the material surface and near the pores). The active sites of the ZIF-8 shell then catalytically kill the enriched microorganisms in situ. (In humid environments (such as wound exudate or moisture in the air), these sites may catalyze the generation of hydroxyl radicals (·OH) and superoxide anions (·O2) through Fenton-like reactions or ligand-metal charge transfer processes.) - These reactive oxygen species (ROS) can irreversibly oxidize and damage the cell membrane lipids, proteins, and DNA of microorganisms, leading to their rapid death. Simultaneously, the unique chemical microenvironment on the ZIF-8 surface may also directly interfere with the normal function of microbial cell membranes, disrupting their permeability and integrity. The entire process does not rely on the release of zinc ions and is a non-leaching catalytic sterilization method. The microorganisms include at least one of *Escherichia coli*, *Staphylococcus aureus*, and *Candida albicans*.

[0052] Example 1 Synthesis of catalytic antibacterial composite material MCM-41@ZIF-8 (1) Dissolve 2.0 g of hexadecyltrimethylammonium bromide (CTAB) in a mixed solution of 240 mL of deionized water and 8 mL of 25% ammonia water, and stir in a water bath at 35 °C until clear. Under vigorous stirring, slowly add 10 mL of tetraethyl orthosilicate (TEOS). After the addition is complete, continue stirring at 35 °C for 3 hours. Transfer the mixture to a high-pressure reactor and crystallize at 110 °C for 36 hours. After cooling, filter, wash with a large amount of deionized water and ethanol, and dry at 80 °C overnight. The obtained powder is calcined at 550 °C for 6 hours at a rate of 1 °C / min to obtain white powder MCM-41. Disperse 0.5 g of the prepared MCM-41 in 50 mL of methanol and sonicate for 30 minutes to obtain suspension A; (2) Dissolve 3.28 g of 2-methylimidazole in 50 mL of methanol to obtain solution B; (3) Dissolve 1.49 g of zinc nitrate hexahydrate in 50 mL of methanol to obtain solution C; (4) Under vigorous stirring, solutions B and C were simultaneously and slowly added dropwise to solution A at a rate of 10 drops per minute. After the addition was complete, the mixture was stirred at room temperature for 6 hours. The product was centrifuged, washed three times with methanol, and dried under vacuum at 60°C for 12 hours to obtain a pale yellow powdery MCM-41@ZIF-8 core-shell composite material. Thermogravimetric analysis showed that the ZIF-8 loading was approximately 45 wt%.

[0053] Comparative Example 1: Synthesis of Pure MCM-41 Material 2.0 g of hexadecyltrimethylammonium bromide (CTAB) was dissolved in a mixed solution of 240 mL deionized water and 8 mL 25% ammonia solution, and stirred in a 35 °C water bath until clear. Under vigorous stirring, 10 mL of tetraethyl orthosilicate (TEOS) was slowly added dropwise. After the addition was complete, the reaction was continued at 35 °C for 3 hours. The mixture was transferred to a high-pressure reactor and crystallized at 110 °C for 36 hours. After cooling, the mixture was filtered, washed with a large amount of deionized water and ethanol, and dried overnight at 80 °C. The resulting powder was calcined at 550 °C at a rate of 1 °C / min for 6 hours to obtain a white powder, MCM-41.

[0054] Comparative Example 2: Synthesis of Pure ZIF-8 Material 3.28 g of 2-methylimidazole was dissolved in 50 mL of methanol (solution B). 1.49 g of zinc nitrate hexahydrate was dissolved in 50 mL of methanol (solution C). Under vigorous stirring, solution C was rapidly poured into solution B, and the reaction was continued at room temperature for 6 hours. The product was centrifuged, washed three times with methanol, and dried under vacuum at 60 °C for 12 hours to obtain a white powder, ZIF-8.

[0055] Test Example 1: Microstructure Characterization XRD characterization analysis was performed on MCM-41@ZIF-8 prepared in Example 1, MCM-41 prepared in Comparative Example 1, and ZIF-8 prepared in Comparative Example 2. The results are as follows: Figure 1 As shown, MCM-41 exhibits typical (100) plane diffraction peaks at 2θ≈2.2°, indicating its ordered mesoporous structure. The diffraction peaks of pure ZIF-8 are consistent with the standard card (ZIF-8). The core-shell composite material MCM-41@ZIF-8 simultaneously exhibits both the low-angle peaks of MCM-41 and the characteristic peaks of ZIF-8, with a slight increase in the peak width of ZIF-8, indicating that it grows on the surface of MCM-41 in the form of smaller grains.

[0056] Test Example 2: Microscopic Morphology Characterization The MCM-41@ZIF-8 prepared in Example 1, the MCM-41 prepared in Comparative Example 1, and the ZIF-8 prepared in Comparative Example 2 were characterized by SEM, and the results are as follows: Figure 2 As shown, MCM-41 is in the form of regular blocks; as Figure 3 As shown, pure ZIF-8 is a rhombic dodecahedron, exhibiting obvious framework structure characteristics of MOF materials; as Figure 4 As shown, in the core-shell composite material MCM-41@ZIF-8, a layer of fine ZIF-8 nanocrystals can be uniformly covered on the surface of MCM-41, confirming the formation of the core-shell structure.

[0057] Test Example 3: Hole Structure Test Nitrogen adsorption tests were performed on MCM-41@ZIF-8 prepared in Example 1, MCM-41 prepared in Comparative Example 1, and ZIF-8 prepared in Comparative Example 2 (using a Micromeritics ASAP 2460 analyzer at 77 K). The results are shown in Table 1. The composite material exhibits a type IV isotherm, combining microporous and mesoporous characteristics. Its specific surface area and pore volume fall between those of MCM-41 and ZIF-8, demonstrating their effective composite composition. The pore size distribution shows that the composite material simultaneously possesses a pore size distribution of approximately 0.8 nm (micropores from ZIF-8) and 3.8 nm (mesopores from MCM-41).

[0058] Table 1

[0059] Test Example 4: Adsorption Performance Test NH3 adsorption isotherm tests were performed on MCM-41@ZIF-8 prepared in Example 1, MCM-41 prepared in Comparative Example 1, and ZIF-8 prepared in Comparative Example 2 (at 87 K). The results are as follows: Figure 5 As shown: (1) Adsorption behavior of MCM-41: Its adsorption isotherm exhibits typical type IV characteristics. In the low-pressure region (P / P0<0.1), the adsorption capacity increases slowly, and when P / P0=0.01, the adsorption capacity is only 25 cm³ / g STP, indicating that the interaction between its surface and ammonia molecules is weak and there are very few micropores. When P / P0 rises to the range of 0.7~0.8, the adsorption capacity increases sharply due to capillary condensation in the mesoporous channels, and the final saturated adsorption capacity is about 350 cm³ / g STP. This confirms its nature as a pure mesoporous material, and its adsorption capacity mainly comes from the multilayer adsorption and capillary condensation filling of the mesopores.

[0060] (2) Adsorption behavior of ZIF-8: Its adsorption isotherm exhibits typical Type I characteristics, which is a hallmark of microporous materials. Under extremely low relative pressure (P / P0<0.01), the adsorption capacity increases sharply, reaching 490 cm³ / g STP at P / P0=0.01, close to 94% of its saturation adsorption capacity (522 cm³ / g STP). After that, the isotherm enters the plateau region. This fully demonstrates that ZIF-8 has a rich and uniformly sized microporous structure, and its Zn-N sites have a strong affinity for polar ammonia molecules, resulting in micropore filling even at extremely low partial pressures.

[0061] (3) Adsorption behavior of MCM-41@ZIF-8 composite material: Its adsorption isotherm shows the composite characteristics of type I and type IV, which directly reflects the successful construction of the core-shell structure: Low pressure region (strong adsorption characteristics): When P / P0=0.01, the ammonia adsorption capacity of the composite material is as high as 380cm³ / gSTP, which is much higher than that of pure MCM-41 (25cm³ / gSTP) and reaches 78% of the corresponding adsorption capacity of pure ZIF-8.

[0062] The above data directly and strongly demonstrate that ZIF-8 nanocrystals have been successfully loaded onto the surface of MCM-41 and exposed a large number of strong adsorption sites, enabling the composite material to achieve excellent low-pressure adsorption (strong adsorption) performance similar to ZIF-8. In the medium-high pressure region (mesoporous adsorption characteristics): as the relative pressure continues to increase, the adsorption capacity of the composite material increases gradually, and a relatively mild adsorption jump occurs after P / P0>0.7, with the final saturated adsorption capacity (422 cm³ / g STP) falling between that of MCM-41 and ZIF-8. This confirms that the mesoporous structure of MCM-41 remains accessible after composite formation, but the capillary condensation effect is weakened compared to pure MCM-41, indicating that the growth of ZIF-8 has a certain modification or confinement effect on some mesoporous inlets or channels.

[0063] Test Example 5: Inhibition Loop Test The inhibition zone experiment (diffusion method) was performed on MCM-41@ZIF-8 prepared in Example 1, MCM-41 prepared in Comparative Example 1, and ZIF-8 prepared in Comparative Example 2. The specific steps are as follows: The test was conducted in accordance with GB / T20944.1-2007 Evaluation of antimicrobial properties of textiles - Part 1: Agar plate diffusion method.

[0064] (1) Preparation of bacterial plates: The bacterial suspensions of Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC6538) and Candida albicans (ATCC10231) were evenly spread on nutrient agar plates or Sabouraud dextrose agar plates respectively.

[0065] (2) Sample Placement: Take 20 mg of each sample powder (MCM-41, ZIF-8, MCM-41@ZIF-8) and place it in a sterile blank paper disc (6 mm in diameter), gently press it down, and place it on the pre-coated agar plate. Use the blank paper disc and commercially available silver-loaded antibacterial powder (Ag) to... + A 2% concentration was used as a control.

[0066] (3) Culture and observation: Bacterial plates were incubated at 37℃ for 24 hours, and fungal plates were incubated at 28℃ for 48 hours. The diameter of the inhibition zone (including the diameter of the paper disc) was measured.

[0067] The results of the inhibition zone experiment are shown in Table 2. MCM-41 showed almost no inhibition zone, indicating that it has no antibacterial activity. Pure ZIF-8 showed a significant inhibition zone (approximately 12-15 mm), proving its catalytic antibacterial ability. The MCM-41@ZIF-8 composite material had the largest inhibition zone (approximately 16-20 mm), significantly better than pure ZIF-8 and commercially available silver-loaded antibacterial agents (approximately 14-16 mm), demonstrating that the synergistic effect of adsorption and catalysis greatly improved the antibacterial efficiency. The blank control showed no inhibition zone.

[0068] Table 2. Diameter of inhibition zone / mm (including paper disc diameter 6 mm)

[0069] Test Example 6: Oscillating Antibacterial Test The MCM-41@ZIF-8 prepared in Example 1, the MCM-41 prepared in Comparative Example 1, and the ZIF-8 prepared in Comparative Example 2 were subjected to an antibacterial test (quantitative). The specific steps were as follows: The antimicrobial properties of textiles—part 3: shaking method—were tested according to GB / T20944.3-2008. The sample powder and bacterial suspension were shaken together for a certain period, and the number of viable bacteria was measured. The antimicrobial rate was calculated. The results are shown in Table 3. The composite material achieved an antimicrobial rate of over 99.9% within a short time (2 hours), and the effect was long-lasting.

[0070] Table 3 Antibacterial rate (%) by shaking method (after 2 hours of action)

[0071] Test Example 7: Dissolution Safety Test Dissolution safety tests were conducted on the MCM-41@ZIF-8 prepared in Example 1, the MCM-41 prepared in Comparative Example 1, and the ZIF-8 prepared in Comparative Example 2. The specific steps were as follows: 0.1 g of the MCM-41@ZIF-8 composite material was immersed in 10 mL of physiological saline (simulated body fluid) and acidic artificial sweat (pH 5.5), and the mixture was kept at 37°C with constant shaking for 24 hours. The supernatant was collected by centrifugation, and the Zn ion concentration was detected by inductively coupled plasma mass spectrometry (ICP-MS), while the presence of organic matter dissolution was detected by high-performance liquid chromatography (HPLC).

[0072] The results showed that Zn² was measured by ICP-MS. + The concentration was below 0.05 ppm (near the instrument's detection limit), far below the drinking water standard (5 ppm) and the concentration of dissolved ions required for antibacterial activity. No characteristic peaks originating from the 2-methylimidazole ligand were detected in the HPLC chromatogram. This demonstrates that the material exhibits virtually no dissolution under actual use conditions and possesses high safety.

[0073] Comparative Example 3: Simple Physical Mixture of MCM-41 / ZIF-8 Materials The MCM-41 prepared in Comparative Example 1 and the ZIF-8 prepared in Comparative Example 2 were simply physically mixed in a mortar at a mass ratio of 55:45 to obtain a simply physically mixed MCM-41 / ZIF-8 material. An antibacterial ring experiment was then performed on this material (using the same test method as in Test Example 5). The results showed that the diameter of the antibacterial ring of the simply physically mixed MCM-41 / ZIF-8 was approximately 13 mm, significantly smaller than the 19.2 mm of the in-situ grown composite material in Example 1 (Table 2). This demonstrates that the tight interfacial bonding and synergistic effect brought about by the core-shell structure are far superior to those of simple physical mixing.

[0074] Comparative Example 4: High ZIF-8 Loading Capacity Composite Material The same steps as in Example 1 were followed, except that the amount of zinc salt and ligand was increased to achieve a ZIF-8 loading of 70 wt%, resulting in a high ZIF-8 loading composite material. Specific surface area (test method same as in Example 3) and inhibition ring experiment (test method same as in Example 5) were then performed on this material. The results showed that the specific surface area of ​​the high ZIF-8 loading composite sample decreased to 950 m² / g, and the inhibition ring experiment showed that its effect (approximately 17 mm) was not significantly improved compared to the 45% loading sample (19.2 mm) in Example 1, and even slightly decreased. This may be because the excessively thick ZIF-8 shell blocked the mesoporous channels of MCM-41, weakening its adsorption and enrichment function, indicating the existence of an optimal loading range.

[0075] Comparative Example 5: Commercial Photocatalytic Antibacterial Agent Compared with commercially available P25 nano-TiO2, an inhibition zone experiment was conducted. The testing method was the same as in Test Example 5, except that when the experiment was conducted under light-protected conditions, it almost did not show an inhibition zone, only exhibiting antibacterial activity under ultraviolet irradiation. This demonstrates that the material of this invention does not depend on an external light source and can work efficiently under normal ambient light or even dark conditions, thus having a wider range of applications.

[0076] In summary, this application successfully prepared a novel MCM-41@ZIF-8 composite material with a core-shell structure. This material combines the strong adsorption capacity of MCM-41 with the non-dissolution catalytic antibacterial activity of ZIF-8, exhibiting highly efficient, rapid, and broad-spectrum killing effects against a variety of common pathogenic microorganisms through a synergistic mechanism of "adsorption enrichment-in-situ catalytic killing." The material exhibits good stability, high safety, no dissolution risk, and is easily compounded with polymer materials, making it particularly suitable for manufacturing various antibacterial nonwoven fabric products for hygiene, medical, and filtration applications with high safety requirements, demonstrating broad market prospects and social benefits.

[0077] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A catalytic antibacterial composite material, characterized in that, include: MCM-41@ZIF-8 core-shell composite material with a hierarchical porous structure; The core is MCM-41 mesoporous molecular sieve; The shell is composed of ZIF-8 nanocrystals grown in situ on the surface and pores of the MCM-41 mesoporous molecular sieve.

2. The catalytic antibacterial composite material according to claim 1, characterized in that, In the MCM-41@ZIF-8 core-shell composite material, the mass percentage of ZIF-8 nanocrystals is 20-60%.

3. The catalytic antibacterial composite material according to claim 1, characterized in that, The MCM-41@ZIF-8 core-shell composite material has at least one of the following properties: The pH of the MCM-41@ZIF-8 core-shell composite material is neutral; No zinc ions or organic ligands were dissolved when the MCM-41@ZIF-8 core-shell composite material was immersed in water, weak acid solution and weak alkali solution. The specific surface area of ​​the MCM-41@ZIF-8 core-shell composite material is 900-1300 m² / g; The pore size distribution of the MCM-41@ZIF-8 core-shell composite material includes both micropores centered at 0.8 nm and mesopores centered at 3.8 nm.

4. The method for preparing the catalytic antibacterial composite material according to any one of claims 1 to 3, characterized in that, include: Provide a suspension A containing MCM-41 mesoporous molecular sieve, provide a solution B containing 2-methylimidazole, and provide a solution C containing zinc salt; Under stirring conditions, solutions B and C are simultaneously and slowly added to suspension A to obtain a mixture. The mixture is then reacted under stirring conditions, and the reaction products are separated, washed, and dried to obtain the MCM-41@ZIF-8 core-shell composite material.

5. The preparation method according to claim 4, characterized in that, The solvents in suspension A, solution B, and solution C are independently selected from at least one of methanol, ethanol, and isopropanol; The zinc salt is selected from at least one of zinc nitrate, zinc chloride, and zinc sulfate; The molar ratio of MCM-41 mesoporous molecular sieve, 2-methylimidazole, and zinc salt in the mixture is 1:(50-70):(15-25).

6. The preparation method according to claim 4, characterized in that, The reaction conditions include: a reaction temperature of 0-30°C and a reaction time of 4-16 hours.

7. The preparation method according to claim 4, characterized in that, The MCM-41 mesoporous molecular sieve is synthesized by a hydrothermal method. The synthesis steps include: using hexadecyltrimethylammonium bromide as a template agent and tetraethyl orthosilicate as a silicon source, hydrothermal crystallization is carried out in an alkaline aqueous solution. After washing and drying, the crystallized product is calcined at 500-600℃ to remove the template agent, thereby obtaining the MCM-41 mesoporous molecular sieve.

8. The use of at least one of the catalytic antibacterial composite materials according to any one of claims 1 to 3 or the catalytic antibacterial composite materials obtained by the preparation method according to any one of claims 4 to 7 as a non-leaching additive in polymer-based antibacterial materials and their products, characterized in that, The catalytic antibacterial composite material is uniformly dispersed in the polymer matrix; The catalytic antibacterial composite material has a mass percentage of 0.5%-5.0% in the polymer matrix.

9. The application according to claim 8, characterized in that, The polymer-based antibacterial material and its products are antibacterial textile materials and textile products made from the antibacterial textile materials.

10. The application according to claim 9, characterized in that, The antibacterial textile material includes antibacterial masterbatch, antibacterial fiber, and nonwoven fabric; The nonwoven fabric is prepared from antibacterial masterbatch and / or antibacterial fibers; The nonwoven fabric includes one of hot air nonwoven fabric, ES fiber nonwoven fabric, spunbond nonwoven fabric, spunlace nonwoven fabric or meltblown fabric. The textile products include children's diaper pads, adult diaper pads, sanitary napkins, medical dressings, air filters, water filters, or pet hygiene products.

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