Activated carbon-based bifunctional material for removing formaldehyde and bacteria as well as preparation method and application of activated carbon-based bifunctional material

Abstract

The invention discloses a formaldehyde-removing and bacterium-removing activated carbon-based bifunctional material as well as a preparation method and application thereof, and aims to solve the technical problems that active components of an existing modified activated carbon material are easy to fall off, and efficient formaldehyde removal and lasting bacterium resistance are difficult to realize at the same time. Comprising an activated carbon carrier and an active component loaded on the activated carbon carrier, wherein the surface of the activated carbon carrier contains oxygen-containing functional groups; the active components comprise an aldehyde removal active component and a bacteria removal active component, and the active components and metal ions in the active components form coordinate bonds or hydrogen bonds through oxygen-containing functional groups; the aldehyde removal active component is metal oxide nano-particles which are selected from at least one of manganese dioxide, zinc oxide, titanium dioxide, copper oxide and iron oxide; the degerming active component is nano-antibacterial metal and / or metal oxide nanoparticles, and is selected from at least one of nano-silver, zinc oxide and copper oxide; the loading capacity of the aldehyde removal active component is 0.5-15 wt% of the total mass of the material; the loading capacity of the antibacterial active component is 0.05-2wt% of the total mass of the material.

Description

Technical Field

[0001] This invention relates to the field of activated carbon-based material preparation technology, specifically to an activated carbon-based dual-functional material for removing formaldehyde and bacteria, its preparation method, and its application. Background Technology

[0002] Activated carbon, due to its large specific surface area and well-developed pore structure, is widely used as an adsorbent to remove gaseous pollutants from indoor air. However, traditional activated carbon has significant limitations in practical applications: First, its removal of formaldehyde mainly relies on physical adsorption, which has a limited adsorption capacity and weak adsorption force. When the ambient temperature or humidity increases, the adsorbed formaldehyde is prone to desorption, causing secondary pollution. Second, for microorganisms, activated carbon can only physically trap some bacteria through its pores and does not have the ability to actively kill them. In humid environments, activated carbon enriched with organic pollutants may become a breeding ground for microorganisms, leading to problems such as odors from the air vents.

[0003] To enhance the functionality of activated carbon, some researchers have attempted to improve its performance through modification. For example, impregnation methods are used to load metal oxides (such as manganese oxide, zinc oxide, and titanium dioxide) to endow it with the ability to catalytically oxidize formaldehyde. Despite some progress, existing modified activated carbon technologies still have the following major shortcomings: First, the design concepts of existing modified activated carbon materials are relatively limited, often targeting only a single pollutant. For example, they may only possess catalytic formaldehyde removal capabilities, which is insufficient to meet the synergistic purification needs of complex pollutants coexisting in modern indoor air environments. Second, the active components loaded through conventional impregnation methods are mostly bound to the activated carbon carrier through physical adsorption or weak interactions, resulting in insufficient binding strength. In actual use, under the influence of continuous airflow or changes in ambient temperature and humidity, the active components are prone to detaching from the carrier surface. This not only leads to a rapid decline in the material's purification performance over time, but the detached nanoparticles may also enter the environment with the airflow, posing a risk of secondary dust pollution. Third, nanoscale metal or metal oxide components have high surface energy and are prone to aggregation during loading. Grouping leads to a significant reduction in the effective specific surface area of ​​the active component and a decrease in the number of exposed active sites. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-functional activated carbon-based material for formaldehyde removal and antibacterial purposes, its preparation method, and its application, in order to solve the technical problems of easy shedding of active components and difficulty in simultaneously achieving efficient formaldehyde removal and long-lasting antibacterial effects in existing modified activated carbon materials.

[0005] Firstly, a dual-functional activated carbon-based material for formaldehyde removal and sterilization includes an activated carbon carrier and an active component loaded on the activated carbon carrier. The activated carbon carrier surface contains oxygen-containing functional groups. The active component includes a formaldehyde-removing active component and a sterilization active component, wherein the active component forms coordination bonds or hydrogen bonds with metal ions in the active component through the oxygen-containing functional groups. The formaldehyde-removing active component is a metal oxide nanoparticle selected from at least one of manganese dioxide, zinc oxide, titanium dioxide, copper oxide, and iron oxide. The sterilization active component is a nano-antibacterial metal and / or metal oxide nanoparticle selected from at least one of nano-silver, zinc oxide, and copper oxide. The loading amount of the formaldehyde-removing active component is 0.5wt%-15wt% of the total material mass; the loading amount of the sterilization active component is 0.05wt%-2wt% of the total material mass. It should be noted that the zinc oxide and copper oxide possess both formaldehyde removal and sterilization properties; when the active component contains zinc oxide or copper oxide, it can simultaneously serve as both a formaldehyde-removing active component and a sterilization active component.

[0006] As an optimization and / or instantiation of the above-mentioned formaldehyde-removing and antibacterial activated carbon-based dual-functional material, further: the specific surface area of ​​the activated carbon carrier is 800 m². 2 / g-1500m 2 / g, iodine value is 900mg / g-1300mg / g.

[0007] As an optimization and / or instantiation of the above-mentioned formaldehyde-removing and antibacterial activated carbon-based dual-functional material, further: the oxygen-containing functional groups abundant on the surface of the activated carbon carrier include phenolic hydroxyl groups, carboxyl groups and ether bonds; the formaldehyde-removing active component is manganese dioxide and / or zinc oxide; the antibacterial active component is nano-silver.

[0008] The second aspect is a method for preparing a formaldehyde-removing and antibacterial activated carbon-based bifunctional material, comprising: sequentially acid washing, water washing, and drying of raw activated carbon, followed by high-temperature activation treatment in a steam atmosphere to obtain an activated carbon carrier; preparing a mixed solution containing a formaldehyde-removing active component precursor and an antibacterial active component precursor; loading the mixed solution onto the activated carbon carrier by impregnation, and supplementing with ultrasonic treatment; drying the impregnated material, followed by calcination at 250℃-550℃ for 1 hour-5 hours in an inert atmosphere, and cooling to obtain the formaldehyde-removing and antibacterial activated carbon-based bifunctional material of the first aspect.

[0009] As an optimization and / or instance of the preparation method of the above-mentioned formaldehyde-removing and antibacterial activated carbon-based bifunctional material, further: the acid washing treatment involves immersing the activated carbon in an acid solution with a concentration of 0.05 mol / L-0.5 mol / L for 1 hour to 4 hours, wherein the acid solution is hydrochloric acid, nitric acid, or sulfuric acid solution; the high-temperature activation treatment is performed at a temperature of 750℃-900℃ for 1 hour to 3 hours, and the ratio of water to carbon is 0.8 mL / g-1.8 mL / g.

[0010] As an optimization and / or instance of the preparation method of the above-mentioned formaldehyde-removing and antibacterial activated carbon-based bifunctional material, further: the formaldehyde-removing active component precursor is selected from at least one of manganese nitrate, manganese acetate, manganese sulfate, zinc nitrate, zinc acetate, zinc sulfate, titanium oxysulfate, copper nitrate, or ferric nitrate, and the total cation concentration of the formaldehyde-removing active component precursor in the mixed solution is 0.01 mol / L-0.5 mol / L; the antibacterial active component precursor is selected from at least one of silver nitrate, zinc nitrate, zinc acetate, or zinc sulfate, and the total cation concentration of the antibacterial active component precursor in the mixed solution is 0.001 mol / L-0.05 mol / L.

[0011] As an optimization and / or instance of the preparation method of the above-mentioned formaldehyde-removing and antibacterial activated carbon-based bifunctional material, the mixed solution further contains a surfactant with a mass fraction of 0.01%-0.5%, selected from at least one of sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide and polyethylene glycol.

[0012] As an optimization and / or instance of the preparation method of the above-mentioned formaldehyde-removing and antibacterial activated carbon-based bifunctional material, further: the impregnation is carried out at 20℃-60℃ for 2-12 hours; the ultrasonic treatment time is 30-60 minutes, the ultrasonic power is 50-200W, and the frequency is 40kHz.

[0013] As an optimization and / or instance of the preparation method of the above-mentioned formaldehyde-removing and antibacterial activated carbon-based bifunctional material, further: the drying step is to dry at 80℃-120℃ for 6-24 hours.

[0014] The third aspect concerns the application of the formaldehyde-removing and antibacterial activated carbon-based dual-function material mentioned in the first aspect in air purification.

[0015] Acid washing and high-temperature activation treatment endow the activated carbon carrier with a large specific surface area, a well-developed pore structure, and abundant surface oxygen-containing functional groups (such as phenolic hydroxyl groups, carboxyl groups, and ether bonds). These functional groups serve as key anchoring points, utilizing the lone pair electrons of oxygen atoms to form strong coordination bonds with metal ions in the formaldehyde-removing and antibacterial active components, or to form hydrogen bonds with the surface of the active components. This firmly anchors the active components and highly disperses them on the surface and within the pores of the carrier, effectively inhibiting particle aggregation and preventing them from falling off during use. During the purification process, the formaldehyde-removing active component catalyzes the physical adsorption and decomposition of formaldehyde into carbon dioxide and water at room temperature, while the antibacterial active component destroys bacterial cell structure by releasing metal ions or generating reactive oxygen species. The synergistic effect of both components, combined with the physical adsorption and retention of the activated carbon carrier, achieves the dual functions of highly efficient formaldehyde removal and long-lasting antibacterial properties. Based on the above mechanism, the technical solution of this invention can produce the following beneficial effects:

[0016] First, by co-loading formaldehyde-removing and antibacterial active components, the high specific surface area of ​​the activated carbon carrier is fully utilized to enrich pollutants. The formaldehyde-removing active component catalyzes the degradation of formaldehyde, while the antibacterial active component releases ions or active oxygen to kill bacteria. The formaldehyde-removing and antibacterial active components are uniformly distributed on the carrier surface, do not interfere with each other, and have a synergistic effect, effectively solving the problem of the single function of traditional materials.

[0017] Secondly, through acid washing and high-temperature activation pretreatment, abundant oxygen-containing functional groups (such as phenolic hydroxyl groups, carboxyl groups, and ether bonds) are introduced onto the surface of the activated carbon support. These functional groups act as "anchors," tightly adsorbing precursor ions through coordination bonds or hydrogen bonds. The subsequent inert atmosphere calcination process further transforms the precursor into stably attached metal oxide nanoparticles or nano-antibacterial metals. This dual effect of chemical bonding and physical anchoring effectively prevents the active components from detaching during use, ensuring the long-term stability of the material's performance.

[0018] Third, the impregnation method combined with ultrasonic treatment, and the optional addition of surfactants, effectively breaks down the aggregation of nanoparticles, allowing the active components to penetrate deep into the micropores and mesopores of the activated carbon support. This high dispersibility not only maximizes the number of exposed active sites, significantly improving catalytic and antibacterial efficiency, but also avoids the decline in adsorption performance caused by pore blockage.

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages provided by the present invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice. Attached Figure Description

[0020] The accompanying drawings, which form part of this specification, are used to aid in understanding the invention. The contents provided in the drawings and their related descriptions in this specification can be used to explain the invention, but do not constitute an undue limitation of the invention.

[0021] Figure 1 This is a SEM analysis image of the sample obtained in Example 4 of the present invention (scale bar = 4 μm).

[0022] Figure 2 This is a SEM analysis image (scale bar = 200 nm) of the sample obtained in Example 4 of the present invention.

[0023] Figure 3 This is the infrared spectrum (FTIR) of the sample obtained in Example 4 of the present invention. Detailed Implementation

[0024] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0025] The technical solutions and features provided in the various sections, including the following description, can be combined with each other without conflict. Furthermore, where possible, these technical solutions, features, and related combinations can be given specific technical subject matter and protected by relevant patents.

[0026] The embodiments of the present invention described below are generally only some embodiments and not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of patent protection.

[0027] The term "comprising" and any variations thereof in this specification, the corresponding claims, and related sections are intended to cover a non-exclusive inclusion. Other related terms and units can be reasonably interpreted based on the relevant content provided in this specification.

[0028] The performance tests of the samples prepared in the embodiments and comparative examples of this invention were all conducted using the following standard methods:

[0029] Formaldehyde removal rate test: The test was conducted according to the formaldehyde clean air delivery rate (CADR) test method in the standard "Air Purifiers" (GB / T 18801-2022). At a 3m... 3 Inside the standard test chamber, 10g of the test material was placed in front of a fan, and formaldehyde gas was introduced into the chamber to achieve an initial concentration of 1.0±0.2mg / m³. 3The fan was started to circulate air, and the temperature inside the chamber was controlled at (25±1)℃ and the relative humidity at (50±5)%. After running for 2 hours, the residual formaldehyde concentration inside the chamber was collected and measured using the phenol reagent spectrophotometric method. Calculation formula: Formaldehyde removal rate (%) = (initial concentration - final concentration) / initial concentration × 100%.

[0030] Antibacterial performance test: The test was conducted using the shaking flask method as described in "Testing of Antibacterial Properties of Nano-Inorganic Materials" (GB / T 21510-2008). The test bacteria were *Escherichia coli* (ATCC 8739) and *Staphylococcus aureus* (ATCC 6538). 0.5 g of the test sample was added to 50 mL of solution containing 10... 5 -10 6 The bacteria were cultured in phosphate buffer at (37±1) ℃ and 150 rpm for 24 hours with shaking. The bacterial suspensions before and after shaking were appropriately diluted, and the number of viable bacteria before and after culture was determined by plate counting. The calculation formula was: Antibacterial rate (%) = (Number of viable bacteria in the control group - Number of viable bacteria in the sample group) / Number of viable bacteria in the control group × 100%.

[0031] Example 1

[0032] This embodiment provides a method for preparing a dual-functional activated carbon-based material for formaldehyde removal and sterilization. The specific steps are as follows: (1) Pretreatment of raw activated carbon: Take 100g of bamboo activated carbon (specific surface area 1150m² / g, iodine value 1050mg / g), place it in 1L of 0.1mol / L hydrochloric acid solution and soak it at room temperature for 2 hours, stirring intermittently during the process. After taking it out, wash it with deionized water until the pH value is 6.5, and dry it at 110℃ for 12 hours. Then, perform high-temperature activation treatment at 800℃ in a water vapor atmosphere for 1.5 hours, with a heating rate of 10℃ / min, and control the ratio of water to carbon to be 1.5mL / g. After natural cooling, an activated carbon carrier with oxygen-containing functional groups on the surface is obtained. (2) Preparation of mixed solution: Weigh 13.8g of manganese nitrate (Mn(NO3)2·4H2O) as the precursor of the formaldehyde removal active component and 0.85g of silver nitrate (AgNO3) as the precursor of the bactericidal active component, dissolve them in 50mL of deionized water, and stir until completely dissolved to obtain a mixed solution. (3) Impregnation and ultrasound: Using the equal volume impregnation method, spray the above mixed solution evenly onto the activated carbon carrier prepared in step (1). Then, perform ultrasonic dispersion treatment for 30 minutes, with an ultrasonic power of 100W and a frequency of 40kHz. After ultrasound, let it stand at 40℃ for 4 hours for impregnation. (4) Drying and calcination: Dry the impregnated material at 105℃ for 12 hours by forced air. Finally, place the dried material in a nitrogen atmosphere and calcine at 400℃ for 3 hours with a heating rate of 5℃ / min. After cooling, the formaldehyde removal and bactericidal activated carbon-based bifunctional material is obtained.

[0033] Example 2

[0034] The difference between this embodiment and Example 1 lies in the different activated carbon raw materials, types of active components, and calcination parameters. (1) Pretreatment of raw activated carbon: 100g of bamboo activated carbon (specific surface area 950m² / g, iodine value 980mg / g) was selected, and the pretreatment process was the same as in Example 1. (2) Preparation of mixed solution: 18.2g of zinc acetate (Zn(CH3COO)2·2H2O) and 0.42g of silver nitrate were weighed and dissolved in 50mL of deionized water. (3) Impregnation and sonication: Same as in Example 1. (4) Drying and calcination: The drying steps were the same as in Example 1; the calcination temperature was adjusted to 350℃ and the calcination time was 4 hours.

[0035] Example 3

[0036] The difference between this embodiment and Example 1 lies in the different activated carbon raw materials, types of active components, and calcination parameters. (1) Pretreatment of raw activated carbon: 100g of fruit shell activated carbon (specific surface area 1250m² / g, iodine value 1100mg / g) was selected, and the pretreatment process was the same as in Example 1. (2) Preparation of mixed solution: 19.6g of titanium oxysulfate (TiOSO4) and 1.2g of copper nitrate (Cu(NO3)2·3H2O) were weighed and dissolved in 50mL of deionized water. The copper component has both catalytic aldehyde removal and antibacterial effects. (3) Impregnation and ultrasound: Same as in Example 1. (4) Drying and calcination: The drying steps were the same as in Example 1; the calcination temperature was adjusted to 500℃ and the calcination time was 2 hours.

[0037] Example 4

[0038] This embodiment aims to verify the effect of mixed metal oxides as an active component for formaldehyde removal. (1) Pretreatment of raw activated carbon: Same as in Example 1. (2) Preparation of mixed solution: Weigh 6.9g of manganese nitrate, 9.1g of zinc acetate and 0.85g of silver nitrate, dissolve in 50mL of deionized water and stir to dissolve. (3) Impregnation and sonication: Same as in Example 1. (4) Drying and calcination: Same as in Example 1.

[0039] Examples 5-6

[0040] Examples 5 and 6 aim to verify the effect of calcination temperature on material properties. Except for the calcination temperature in step (4), the raw materials and steps are the same as in Example 1. Example 5: Calcination temperature was 250℃. Example 6: Calcination temperature was 550℃.

[0041] Examples 7-8

[0042] Examples 7 and 8 were designed to verify the effect of precursor concentration (i.e., loading) on ​​material properties. Except for the amount of precursor used in step (2), the raw materials and steps were the same as in Example 1. Example 7 (low concentration): 2.76 g of manganese nitrate and 0.17 g of silver nitrate were weighed. Example 8 (high concentration): 27.6 g of manganese nitrate and 1.7 g of silver nitrate were weighed.

[0043] Example 9

[0044] This embodiment aims to verify the effect of the acid washing pretreatment step. 100g of bamboo activated carbon, the same as in Example 1, was taken, and the acid washing step in step (1) was omitted. After washing with water, it was directly activated by high-temperature steam. The remaining steps (2)-(4) were the same as in Example 1.

[0045] Example 10

[0046] This embodiment aims to verify the effect of the high-temperature activation step. 100g of bamboo activated carbon, the same as in Example 1, was acid-washed and water-washed, but the high-temperature steam activation step in step (1) was omitted. The remaining steps (2)-(4) are the same as in Example 1.

[0047] Example 11

[0048] This embodiment aims to verify the effect of soaking time. Except for the change of the standing soaking time in step (3) to 12 hours, the other raw materials and steps are the same as in Example 1.

[0049] Example 12

[0050] This example aims to verify the effect of surfactants. In step (2) of Example 1, an additional 0.1 g of sodium dodecylbenzenesulfonate (SDBS) was added to the mixed solution and stirred thoroughly to dissolve. The remaining steps were the same as in Example 1.

[0051] Example 13

[0052] This embodiment aims to verify the universality of different carrier types and process parameters. (1) Pretreatment of raw activated carbon: Take 100g of coal-based activated carbon (specific surface area 800m² / g, iodine value 900mg / g) and soak it in 1L of 0.3mol / L nitric acid solution at room temperature for 3 hours. After washing with water until neutral, dry at 110℃. Then activate it at 850℃ in a steam atmosphere for 2 hours, with a water:carbon ratio of 1.5mL / g. (2) Preparation of mixed solution: Weigh 14.5g of ferric nitrate (Fe(NO3)3·9H2O) and 0.85g of silver nitrate and dissolve them in 50mL of deionized water. (3) Impregnation and sonication: After spraying, sonicate for 45 minutes (100W, 40kHz), and then let it stand at 50℃ for 6 hours. (4) Drying and calcination: Dry at 105℃ for 18 hours; calcinate at 450℃ in a nitrogen atmosphere for 2.4 hours.

[0053] Comparative Example 1

[0054] Take 100g of bamboo activated carbon from Example 1 and perform only the pretreatment (acid washing, water washing, activation) step (1) of Example 1 without performing the subsequent active component loading, drying and calcination steps.

[0055] Comparative Example 2

[0056] Take 100g of bamboo activated carbon from Example 1, and without undergoing the acid washing and activation pretreatment in step (1), directly carry out the loading, drying and calcination operations in steps (2)-(4) of Example 1.

[0057] Comparative Example 3

[0058] The activated carbon carrier pretreated in step (1) of Example 1 was mechanically mixed with commercially available manganese dioxide powder (particle size approximately 1 μm) and nano-silver powder. The mass ratio of activated carbon, MnO2, and Ag was controlled to be consistent with the theoretical content after loading in Example 1. The mixing time was 2 hours, and no subsequent calcination was performed.

[0059] The preparation parameters for each embodiment and comparative example are summarized in Table 1, and the performance test results are summarized in Table 2.

[0060] Table 1 Summary of key preparation parameters for each embodiment and comparative example

[0061] Example number <![CDATA[Type of activated carbon (specific surface area m 2 / g)]]> Pretreatment acid concentration (mol / L) / Activation temperature (°C) Formaldehyde removal precursor (dosage, g) Sterilization precursor (dosage, g) Calcination temperature (°C) / Time (h) 1 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Mn(NO3)2·4H2O (13.8)]]> <![CDATA[AgNO3(0.85)]]> 400 / 3 2 Bamboo (950) HCl 0.1 / 800 <![CDATA[Zn(CH3COO)2·2H2O (18.2)]]> <![CDATA[AgNO3(0.42)]]> 350 / 4 3 Nutshell (1250) HCl 0.1 / 800 <![CDATA[TiOSO4 (19.6), Cu(NO3)2·3H2O (1.2)]]> (Cu element has multiple functions) 500 / 2 4 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Mn(NO3)2·4H2O (6.9), Zn(CH3COO)2·2H2O (9.1)]]> <![CDATA[AgNO3(0.85)]]> 400 / 3 5 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Mn(NO3)2·4H2O (13.8)]]> <![CDATA[AgNO3(0.85)]]> 250 / 3 6 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Mn(NO3)2·4H2O (13.8)]]> <![CDATA[AgNO3(0.85)]]> 550 / 3 7 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Mn(NO3)2·4H2O (2.76)]]> <![CDATA[AgNO3(0.17)]]> 400 / 3 8 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Mn(NO3)2·4H2O (27.6)]]> <![CDATA[AgNO3 (1.7)]]> 400 / 3 9 Bamboo (1150) Acid-free pickling / 800 <![CDATA[Mn(NO3)2·4H2O (13.8)]]> <![CDATA[AgNO3(0.85)]]> 400 / 3 10 Bamboo (1150) HCl 0.1 / Unactivated <![CDATA[Mn(NO3)2·4H2O (13.8)]]> <![CDATA[AgNO3(0.85)]]> 400 / 3 11 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Mn(NO3)2·4H2O (13.8)]]> <![CDATA[AgNO3(0.85)]]> 400 / 3 (Soaking for 12 hours) 12 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Mn(NO3)2·4H2O (13.8)]]> <![CDATA[AgNO3(0.85) (+SDBS)]]> 400 / 3 13 Coal quality (800) <![CDATA[HNO3 0.3 / 850]]> <![CDATA[Fe(NO3)3·9H2O (14.5)]]> <![CDATA[AgNO3(0.85)]]> 450 / 2.5 Comparative Example 1 Bamboo (1150) HCl 0.1 / 800 No load No load Uncalcined Comparative Example 2 Bamboo (1150) No pretreatment <![CDATA[Mn(NO3)2·4H2O (13.8)]]> <![CDATA[AgNO3(0.85)]]> 400 / 3 Comparative Example 3 Bamboo (1150) HCl 0.1 / 800 <![CDATA[Physically mixed MnO2]]> Physical mixing of n-Ag Uncalcined

[0062] Table 2 Performance test results of each embodiment and comparative example

[0063]

[0064] Figure 1 The image shown is a low-magnification image (scale bar = 4 μm), revealing the overall morphology and hierarchical pore structure of the activated carbon support. The activated carbon support exhibits a rich, uneven surface and a highly developed pore structure, including numerous mesopores and macropores visible on SEM. This hierarchical pore structure not only significantly increases the specific surface area, providing numerous adsorption sites for formaldehyde molecules, but also provides space for microorganisms such as E. coli to enter and attach, thus significantly enhancing the material's adsorption capacity for bacteria through physical retention.

[0065] Figure 2 A high-magnification image (scale bar = 200 nm) shows the detailed morphology of the active component particles loaded on the surface of the activated carbon carrier. It can be clearly observed that the formaldehyde-removing active component (metal oxide nanoparticles) and the antibacterial active component (silver nanoparticles) have been successfully loaded onto the surface and pores of the activated carbon. Due to the high surface energy of the nanoparticles, a certain aggregation effect occurs, forming aggregates of varying sizes. Among them, the highly active silver nanoparticles release silver ions (Ag... + The ability of the material to generate reactive oxygen species (ROS) that damage bacterial structures is a key reason why it possesses efficient and long-lasting antibacterial properties.

[0066] Figure 3 3431cm -1 The absorption peak at 1630 cm⁻¹ corresponds to the stretching vibration of the OH bond (possibly an alcohol hydroxyl group or an associated hydroxyl group), and is related to the absorption peak at 1630 cm⁻¹. -1 The bending vibration peaks of the HOH bond echo each other, further confirming the existence of the hydroxyl structure; meanwhile, at 1129 cm⁻¹... -1The absorption peak at 615 cm⁻¹ corresponds to the stretching vibration of the CO bond (a characteristic peak of the CO bond in ethers or alcohols). Based on these peak characteristics, it can be determined that oxygen-containing functional groups such as hydroxyl groups (-OH), ether bonds (COC), or CO bonds of alcohols have been successfully introduced onto the surface of the activated carbon support. These functional groups can provide support for the stable anchoring of the active components through coordination (the combination of the hydroxyl O atom with metal ions) or by improving interfacial compatibility. Furthermore, the absorption peak at 615 cm⁻¹... -1 The absorption peak at that point corresponds to the MO bond of the metal oxide, indicating that the aldehyde removal active component and the antibacterial active component have been successfully loaded onto the catalyst surface.

[0067] Comparing Example 1 and Comparative Example 1, it can be seen that although the unmodified activated carbon carrier was activated, its formaldehyde removal rate was only 35.2% (mainly relying on physical adsorption) and it had almost no antibacterial ability. In contrast, the bifunctional material prepared in Example 1 had a formaldehyde removal rate as high as 94.5% and an antibacterial rate of more than 99.9%, proving the necessity of loading the active component.

[0068] Comparing Example 1 and Comparative Example 3, it is evident that the material prepared using the impregnation-calcination process of this invention exhibits significantly superior performance compared to simple physical mixing. The physical mixing method (Comparative Example 3) suffers from weak bonding between the active component and the carrier, leading to easy detachment and a formaldehyde removal rate of only 78.5%, along with a low and unstable antibacterial rate. This verifies the mechanistic advantage of this invention, which uses both chemical bonding and physical anchoring to immobilize the active component.

[0069] Comparing Example 1 with Comparative Examples 2, 9, and 10, it is evident that complete pretreatment (acid washing + high-temperature activation) is crucial for improving material performance. Comparative Example 2, lacking pretreatment, suffered from a deficiency of oxygen-containing functional groups on its surface, resulting in poor dispersion and weak adhesion of the active components, leading to a formaldehyde removal rate as low as 82.1%. The performance of Examples 9 (without acid washing) and 10 (without activation) was also lower than that of Example 1, indicating that acid washing to remove impurities and high-temperature activation to create pores and introduce functional groups are fundamental to achieving high dispersion and loading of the active components.

[0070] Influence of Active Components and Process Parameters: Synergistic Effect of Active Components: Example 4 used a manganese-zinc composite oxide, whose formaldehyde removal rate was slightly higher than that of Example 1 using a single manganese oxide, indicating a possible synergistic catalytic effect between different metal oxides. Calcination Temperature: Example 5 showed that too low a calcination temperature (250℃) would lead to incomplete decomposition of the precursor, affecting catalytic activity; while Example 6 showed that the material performance remained stable at 550℃. Loading Amount: Example 7 reduced the loading amount, resulting in a slight decrease in performance; Example 8 significantly increased the loading amount, but the performance improvement was not significant and it may have caused slight agglomeration, indicating that the loading range set in this invention is reasonable. Dispersion Method: In Example 12, the addition of the surfactant SDBS increased the formaldehyde removal rate to 95.5%, proving that surfactants help break up nanoparticle agglomeration and further increase the exposure of active sites.

[0071] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the foregoing content of this specification without inventive effort should fall within the scope of the present invention.

Claims

1. A bifunctional material of aldehyde-removing and bacteria-removing activated carbon base, characterized in that: The material comprises an activated carbon carrier and active components loaded on the activated carbon carrier; wherein the surface of the activated carbon carrier contains oxygen-containing functional groups; the active components include an aldehyde-removing active component and an antibacterial active component, wherein the active components form coordination bonds or hydrogen bonds with metal ions in the active components through the oxygen-containing functional groups; the aldehyde-removing active component is a metal oxide nanoparticle selected from at least one of manganese dioxide, zinc oxide, titanium dioxide, copper oxide, and iron oxide; the antibacterial active component is a nano-antibacterial metal and / or metal oxide nanoparticle selected from at least one of nano-silver, zinc oxide, and copper oxide; the loading amount of the aldehyde-removing active component is 0.5wt%-15wt% of the total mass of the material; the loading amount of the antibacterial active component is 0.05wt%-2wt% of the total mass of the material.

2. The aldehyde-removing and bacteria-removing activated carbon-based bifunctional material of claim 1, characterized in that: The specific surface area of ​​the activated carbon carrier is 800 m². 2 / g-1500m 2 / g, iodine value is 900mg / g-1300mg / g.

3. The formaldehyde-removing and antibacterial activated carbon-based dual-functional material as described in claim 1, characterized in that: The activated carbon carrier surface is rich in oxygen-containing functional groups including phenolic hydroxyl groups, carboxyl groups and ether bonds; the aldehyde removal active component is manganese dioxide and / or zinc oxide; the antibacterial active component is nano-silver.

4. A method for preparing an activated carbon-based dual-functional material for formaldehyde removal and sterilization, characterized in that: include: The raw activated carbon was sequentially acid-washed, water-washed, and dried, and then subjected to high-temperature activation treatment in a steam atmosphere to obtain an activated carbon carrier. A mixed solution containing a precursor of formaldehyde-removing active ingredient and a precursor of antibacterial active ingredient is prepared; the mixed solution is loaded onto the activated carbon carrier by impregnation and then subjected to ultrasonic treatment. The impregnated material is dried, and then calcined at 250℃-550℃ for 1 hour to 5 hours in an inert atmosphere. After cooling, the formaldehyde-removing and antibacterial activated carbon-based dual-function material as described in any one of claims 1-3 is obtained.

5. The preparation method of the formaldehyde-removing and antibacterial activated carbon-based dual-functional material as described in claim 4, characterized in that: The acid washing treatment involves immersing activated carbon in an acid solution with a concentration of 0.05 mol / L to 0.5 mol / L for 1 to 4 hours. The acid solution is hydrochloric acid, nitric acid, or sulfuric acid. The high-temperature activation treatment is performed at a temperature of 750℃ to 900℃ for 1 to 3 hours, with a water-to-carbon ratio of 0.8 mL / g to 1.8 mL / g.

6. The method for preparing the bifunctional material of removing aldehyde and bacteria-removing activated carbon according to claim 4, characterized in that: The formaldehyde-removing active component precursor is selected from at least one of manganese nitrate, manganese acetate, manganese sulfate, zinc nitrate, zinc acetate, zinc sulfate, titanium oxysulfate, copper nitrate, or ferric nitrate, and the total cation concentration of the formaldehyde-removing active component precursor in the mixed solution is 0.01 mol / L-0.5 mol / L; the antibacterial active component precursor is selected from at least one of silver nitrate, zinc nitrate, zinc acetate, or zinc sulfate, and the total cation concentration of the antibacterial active component precursor in the mixed solution is 0.001 mol / L-0.05 mol / L.

7. The method of claim 4, wherein the method is characterized by: The mixed solution also contains 0.01%-0.5% by mass of a surfactant selected from at least one of sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, and polyethylene glycol.

8. The method of claim 4, wherein the method is characterized by: The impregnation is carried out at 20℃-60℃ for 2-12 hours; the ultrasonic treatment takes 30-60 minutes, with an ultrasonic power of 50-200W and a frequency of 40kHz.

9. The method of claim 4, wherein the method is characterized by: The drying step involves drying at 80℃-120℃ for 6-24 hours.

10. Use of the bifunctional material of any one of claims 1 to 3 in air purification.

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