Air purification MOF activated carbon composite material, preparation method and application

Abstract

The present application relates to air purification material technical field, especially to a kind of air purification MOF activated carbon composite material, preparation method and application.The composite material is prepared by the method.The method comprises: under the condition of stirring, MOF-active component suspension is gradually added to pretreated activated carbon, and continuously stirring 2~4h;Subsequently, gradually add binder solution, and continuously stirring 1~3h, to obtain composite slurry;The composite slurry is heated by water bath treatment, to obtain slurry material;Slurry material is laid on carrier, and sequentially after solidification treatment and calcination treatment, to obtain the composite material.The application includes the application of the composite material in purifying formaldehyde and in purifying toluene.The present application can prepare composite material with large adsorption capacity, low cost, high catalytic activity, good stability, strong moisture resistance, and air purification can be realized in indoor environment conditions with light or without light.

Description

Technical Field

[0001] This invention relates to the field of air purification materials technology, and in particular to an air purification MOF activated carbon composite material, its preparation method, and its application. Background Technology

[0002] Air pollution from indoor decoration cannot be ignored. Formaldehyde and toluene, as representative indoor volatile organic compounds (VOCs), have been identified by the World Health Organization as strong carcinogens and teratogens, seriously endangering human health. Currently, technologies for treating indoor VOCs mainly include adsorption, photocatalysis, and low-temperature catalytic oxidation. Among these, low-temperature catalytic oxidation is recognized as the most thorough method for treating indoor VOCs, capable of converting VOCs into CO2 and H2O at low temperatures. While noble metal catalysts (such as Pt and Pd) used in low-temperature catalytic oxidation have high activity, they are expensive; while some non-noble metal oxide catalysts (such as MnO2 and CeO2) are cheaper, they have low catalytic activity and poor stability in high humidity environments, making them prone to deactivation.

[0003] Currently, the industry is also using MOF activated carbon composite materials for air purification. For example, invention patent CN119926362A discloses an environmentally friendly gelling material for efficient formaldehyde adsorption and its preparation method. It uses activated carbon loaded with metal-organic framework (MOF) powder to adsorb formaldehyde, but it only enriches the formaldehyde rather than catalytically decomposes it, resulting in adsorption saturation problems. Another invention patent CN120575362A discloses an activated carbon fiber for efficient formaldehyde removal and its preparation method. By constructing a composite fiber structure of activated carbon and porous TiO2 derived from metal-organic framework (MOF), it synergistically combines physical adsorption and photocatalytic degradation functions, solving the interfacial bonding problem between MOF derivatives and activated carbon. This achieves highly dispersed loading and stable and firm composite of active components, but it requires light (such as ultraviolet light) excitation to operate. If under weak light or no light conditions indoors, the catalytic efficiency is low, and harmful byproducts may be generated.

[0004] Therefore, it is necessary to provide an air purification MOF activated carbon composite material, its preparation method, and its application to solve the problems of high cost of precious metal catalysts, low catalytic activity and poor moisture resistance of non-precious metal oxide catalysts used in low-temperature catalytic oxidation methods; and to solve the problems that existing air purification MOF activated carbon composite materials only enrich formaldehyde rather than catalytically decompose it, and that they need to operate under photoexcitation. Summary of the Invention

[0005] The purpose of this invention is to provide an air purification MOF activated carbon composite material, its preparation method, and its application. The specific technical solution is as follows:

[0006] In a first aspect, the present invention provides a method for preparing an air-purifying MOF activated carbon composite material, comprising:

[0007] Step S1: Under stirring conditions, the MOF-active component suspension is gradually added to the pretreated activated carbon and stirred continuously for 2-4 hours; then, the binder solution is gradually added and stirred continuously for 1-3 hours to obtain the composite slurry.

[0008] The active components used include Mn, Co, and Ce;

[0009] The pretreatment includes drying the activated carbon after the strong acid solution has been refluxed.

[0010] Step S2: The composite slurry is heated in a water bath to obtain a slurry material;

[0011] Step S3: Spread the slurry material evenly on the carrier, and then perform curing and calcination treatments in sequence to obtain an air purification MOF activated carbon composite material.

[0012] Optionally, in step S1, the step of obtaining the MOF-active component suspension includes:

[0013] Based on 100 parts by mass of activated carbon, 10-15 parts by mass of MOF powder and 1-5 parts by mass of active component are added to an alcohol reagent and ultrasonically dispersed to obtain the MOF-active component suspension.

[0014] In the active component, the molar ratio of Mn:Co:Ce is 4~5:1~3:1~3; the Mn is derived from manganese salt; the manganese salt includes manganese nitrate; the Co is derived from cobalt salt; the manganese salt includes cobalt nitrate; the Ce is derived from cerium salt; the cerium salt includes cerium nitrate.

[0015] The volume ratio of the alcohol reagent to the mass ratio of the activated carbon is 100~120mL:100g;

[0016] The alcohol reagent includes ethanol;

[0017] The ultrasonic dispersion process uses an ultrasonic power of 200-300W and an ultrasonic time of 10-30min.

[0018] The MOF powder has a pore size of 1~2 nm.

[0019] Optionally, in step S1, the reflux treatment includes adding the strong acid solution to 100 parts by mass of activated carbon and refluxing for 4-6 hours under stirring conditions.

[0020] The reflux temperature is 90±5℃;

[0021] The molar concentration of the strong acid solution is 3 ± 0.5 mol / L;

[0022] The volume ratio of the strong acid solution to the mass ratio of the activated carbon is 1000~1500mL:100g;

[0023] The strong acid solution includes a nitric acid solution;

[0024] The activated carbon includes coconut shell activated carbon;

[0025] The particle size of the coconut shell activated carbon is 50-100 mesh;

[0026] The specific surface area of ​​the coconut shell activated carbon is ≥1000 m². 2 / g.

[0027] Optionally, between the reflux treatment and the drying treatment, the activated carbon filtered out after the reflux treatment is further washed with water until the pH of the washing solution is 6.5~7.0.

[0028] The drying process uses a drying temperature of 100~120℃ and a drying time of 12~20h to dry the water-washed activated carbon to a constant weight.

[0029] Optionally, in step S1, the step of obtaining the adhesive solution includes:

[0030] Based on 100 parts by weight of activated carbon, 5-6 parts by weight of silica sol, 1-4 parts by weight of aqueous polyurethane dispersion and 0.01-0.07 parts by weight of silane coupling agent are mixed and stirred continuously in a water bath at 60±5℃ for 2-4 hours to obtain the adhesive solution.

[0031] The mass percentage of SiO2 in the silica sol is 10% to 30%.

[0032] The solid content of the aqueous polyurethane dispersion is 20%~40%;

[0033] The silane coupling agent includes KH-550.

[0034] Optionally, in step S2, the water bath heating treatment uses a heating temperature of 60±5℃ and a heating time of 10~30min.

[0035] Optionally, in step S3, the curing temperature is 80±5℃ and the curing time is 2~5h.

[0036] The calcination process uses a calcination temperature of 200~270℃ and a calcination time of 1~3h; wherein the heating rate from the curing temperature to the calcination temperature is 3~5℃ / min.

[0037] In a second aspect, the present invention provides an air-purifying MOF activated carbon composite material, which is prepared by the aforementioned method for preparing air-purifying MOF activated carbon composite material.

[0038] In a third aspect, the present invention provides the application of the aforementioned air-purifying MOF activated carbon composite material in the purification of formaldehyde.

[0039] In a fourth aspect, the present invention provides the application of the aforementioned air-purifying MOF activated carbon composite material in the purification of toluene.

[0040] The application of the technical solution of the present invention has at least the following beneficial effects:

[0041] (1) The present invention provides a method for preparing an air-purifying MOF activated carbon composite material, which can produce a composite material with large adsorption capacity, low cost, high catalytic activity, good stability, strong moisture resistance, and the ability to purify air under both light and dark indoor environmental conditions. The specific principle is as follows:

[0042] The pretreated activated carbon particles form a main channel for the rapid diffusion of the air to be purified (such as toluene and formaldehyde), enabling rapid capture and initial conduction of toluene and formaldehyde in the air. The microporous-mesoporous hierarchical structure (pore size 1-50 nm) inside the activated carbon provides a huge specific surface area. Furthermore, after reflux treatment with strong acid solution, multiple oxygen-containing functional groups such as carboxyl and phenolic hydroxyl groups are introduced onto the outer surface and inner surface of the pores of the activated carbon. These oxygen-containing functional groups enhance the chemical adsorption capacity for polar formaldehyde molecules and also provide anchoring sites for MOF growth. Specifically, the lone pair electrons on the oxygen atoms in these oxygen-containing functional groups coordinate with the empty orbitals of metal ions in the MOF, forming strong coordinate bonds that anchor the MOF to the activated carbon. Further, the pores of the MOF... With a particle size of 1–2 nm, it exhibits a molecular sieve effect, effectively adsorbing toluene and formaldehyde molecules with a kinetic diameter less than 1 nm. Furthermore, the active components Mn, Co, and Ce can be confined within the MOF channels, ensuring the particle size of the active components is strictly controlled to <2 nm. This particle size increases the proportion of exposed active crystal faces, significantly increasing the number of active sites and enhancing catalytic activity. Additionally, the pore confinement effect of the MOF prevents the active components from agglomerating and atrophying during calcination, which could lead to decreased activity or deactivation. Moreover, calcination allows the metal atoms of the active components to form coordination bonds with nitrogen and oxygen atoms on the MOF organic ligands, stably confining the active components within the MOF channels and contributing to improved composite material stability. The active components Mn, Co, and Ce used in this invention, after curing and calcination, can be oxidized to manganese oxide, cobalt oxide, and cerium oxide, respectively. These three oxides synergistically and efficiently catalyze the decomposition of formaldehyde. The specific catalytic principle is as follows:

[0043] Manganese oxides utilize their unique electronic structure to form abundant oxygen vacancies on their surface, strongly adsorbing and breaking down oxygen molecules, converting them into highly reactive atomic oxygen.

[0044] Cobalt oxides, with their excellent electron transport capabilities, are primarily responsible for "capturing" and "activating" formaldehyde, weakening its CH bonds, making it easier for it to react with highly reactive atomic oxygen, and ultimately being completely oxidized into CO2 and H2O.

[0045] Cerium oxide through Ce 3+ / Ce 4+ The reversibility of the valence state enables the storage and release of oxygen. That is, oxygen is stored when there is sufficient oxygen and released immediately when a large amount of oxygen is consumed. This ensures that manganese oxides continuously provide highly active atomic oxygen for the decomposition of formaldehyde, thereby achieving the synergistic and efficient catalytic decomposition of formaldehyde by manganese oxides, cobalt oxides, and cerium oxides.

[0046] Furthermore, as formaldehyde is continuously decomposed by the active components, formaldehyde molecules can be continuously adsorbed within the MOF channels, and then continuously decomposed by the active components, ultimately achieving complete purification of formaldehyde in indoor air.

[0047] Furthermore, the active components Mn, Co, and Ce used in this invention are all non-precious metals, which greatly reduces the preparation cost. The composite slurry formed under stirring conditions in step S1 of this invention facilitates the uniform dispersion of the MOF-active components in the pretreated activated carbon. The binder solution used in this invention helps to improve the adhesion between the MOF-active components and the activated carbon, thereby improving the stability of the composite material. In step S3 of this invention, the slurry material is first spread evenly on a ceramic boat, and then solidified and calcined in sequence, which facilitates the full and uniform oxidation of the active components into manganese oxide, cobalt oxide, and cerium oxide, thereby improving the catalytic activity of the composite material.

[0048] Regarding strong moisture resistance, firstly, the composite material prepared in this invention contains MOF material, which is uniformly anchored on activated carbon. The hydrophobicity and size sieving effect of the MOF material itself can effectively repel water molecules and prevent them from capillary agglomeration in the composite material. Secondly, the composite material prepared in this invention contains active components Mn, Co, and Ce, which can be oxidized into manganese oxide, cobalt oxide, and cerium oxide after curing and calcination. All of these have moisture resistance. Even in high humidity environments where oxygen is scarce, cerium oxide can release stored oxygen, ensuring that manganese oxide continuously provides highly active atomic oxygen for formaldehyde decomposition. This achieves synergistic and efficient catalytic decomposition of formaldehyde by manganese oxide, cobalt oxide, and cerium oxide, ensuring the continuous operation of the catalytic chain. In addition, the active components Mn, Co, and Ce have a better affinity for formaldehyde pollutants than for water molecules. Therefore, even when water molecules coexist, they can preferentially capture and degrade the target pollutant formaldehyde, thus achieving efficient and long-lasting purification under high humidity conditions.

[0049] (2) In this invention, the use of silica sol, aqueous polyurethane dispersion, and silane coupling agent in the adhesive solution can synergistically form a dual network bonding structure between activated carbon and MOF. On the one hand, this ensures that the MOF-active component is firmly fixed with a shedding rate of <1%. On the other hand, it does not clog the pores of activated carbon and MOF, thus avoiding affecting the adsorption performance. Specifically, the curing and calcination processes cause the silanol groups (-Si-OH) of the silane coupling agent to undergo dehydration condensation with the carboxyl groups and / or phenolic hydroxyl groups on the surface of activated carbon, generating strong Si-OC covalent bonds; the amino groups (-NH2) of the silane coupling agent react with the groups on the aqueous polyurethane chain segments (such as the residual isocyanate groups -NCO) to generate stable urea bonds; the nitrogen atom of the amino group of the silane coupling agent has a lone pair of electrons, which can also coordinate with the empty orbitals of metal ions in MOF to form coordinate bonds; during the curing stage, hydrogen bonds are formed between the carbonyl groups on one molecular chain of the aqueous polyurethane and the amino groups on another molecular chain. Numerous hydrogen bonds act as "buttons" between different molecular chains. The "-Si-O-Si-" structure binds the waterborne polyurethane together, crosslinking to form a strong yet flexible three-dimensional network, preventing the bonding structure from cracking and causing the MOF-active component to detach. During the calcination stage, it promotes a large number of thorough dehydration reactions between the silanol groups (-Si-OH) inside the silica sol, thereby generating a dense and hard -Si-O-Si- three-dimensional network skeleton. This -Si-O-Si- three-dimensional network skeleton and the waterborne polyurethane form a flexible three-dimensional network that interpenetrates with each other, forming a stable interpenetrating double network structure between the activated carbon and MOF. This not only ensures that the MOF-active component is firmly fixed with a detachment rate of <1%, but also prevents the pores of the activated carbon and MOF from being blocked.

[0050] (3) The air purification MOF activated carbon composite material prepared in this invention can maintain a formaldehyde conversion rate of over 85% after purifying formaldehyde for 100 hours.

[0051] (4) The air purification MOF activated carbon composite material prepared in this invention has a toluene penetration adsorption capacity of more than 265 mg / g in terms of toluene purification.

[0052] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0054] Figure 1 This is a data graph of the formaldehyde purification test results in Example 1.

[0055] Figure 2 This is a data graph showing the toluene purification test results in Example 1. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0057] Example 1:

[0058] A method for preparing an air purification MOF activated carbon composite material, comprising:

[0059] Step S1: Under stirring conditions (stirring speed of 30~50 rpm, 50 rpm can be selected), gradually add the MOF-active component suspension to the pretreated activated carbon (the pretreated activated carbon is placed in a 2000 mL beaker in advance) and continue stirring for 2~4 h (e.g., stirring for 2 h); then, gradually add the binder solution and continue stirring for 1~3 h (e.g., stirring for 1 h) to obtain the composite slurry;

[0060] The active components used include Mn, Co, and Ce;

[0061] The pretreatment includes drying the activated carbon after reflux treatment with strong acid solution (completed in an oven).

[0062] Step S2: The composite slurry is heated in a water bath to obtain a slurry material;

[0063] Step S3: Spread the slurry material evenly on a carrier (such as a ceramic boat), and then perform a curing treatment (completed in an oven) and a calcination treatment (completed in a muffle furnace) in sequence. After that, allow it to cool naturally to room temperature to obtain an air purification MOF activated carbon composite material.

[0064] In step S1, the step of obtaining the MOF-active component suspension includes:

[0065] Based on 100 parts by mass (specifically 100g) of activated carbon, 10-15 parts by mass (specifically 12g) of MOF powder (specifically metal-organic framework powder) and 1-5 parts by mass (specifically 3g) of active component are added to an alcohol reagent and ultrasonically dispersed to obtain the MOF-active component suspension.

[0066] In the active components, the molar ratio of Mn:Co:Ce is 5:3:2; the Mn is derived from manganese salt; the manganese salt is manganese nitrate; the Co is derived from cobalt salt; the manganese salt is cobalt nitrate; the Ce is derived from cerium salt; the cerium salt is cerium nitrate.

[0067] The volume ratio of the alcohol reagent to the mass ratio of the activated carbon is 100-120 mL: 100 g (specifically 100 mL: 100 g).

[0068] The alcohol reagent is ethanol;

[0069] The ultrasonic dispersion process uses an ultrasonic power of 300W and an ultrasonic time of 10~30min (specifically 30min).

[0070] The MOF powder has a pore size of 1~2 nm.

[0071] In step S1, the reflux treatment includes adding the strong acid solution to 100 parts by mass of activated carbon (the activated carbon is added to a 2000 mL three-necked flask in advance), and refluxing for 4 to 6 hours under stirring conditions (stirring speed of 30 to 50 rpm, 50 rpm can be selected).

[0072] The reflux temperature is 90±5℃ (specifically 90℃).

[0073] The molar concentration of the strong acid solution is 3 ± 0.5 mol / L (specifically 3 mol / L).

[0074] The volume ratio of the strong acid solution to the mass ratio of the activated carbon is 1000~1500mL:100g (specifically 1500mL:100g).

[0075] The strong acid solution is a nitric acid solution;

[0076] The activated carbon is coconut shell activated carbon;

[0077] The particle size of the coconut shell activated carbon is 50-100 mesh;

[0078] The specific surface area of ​​the coconut shell activated carbon is ≥1000 m². 2 / g; the iodine value of the coconut shell activated carbon is 1000.

[0079] Between the reflux treatment and the drying treatment, the activated carbon filtered out after the reflux treatment is washed with water (specifically, repeatedly washed with deionized water) until the pH of the washing solution is 6.5~7.0 (specifically 7.0).

[0080] The drying process uses a drying temperature of 100~120℃ (specifically 110℃) and a drying time of 12~20h (specifically 12h) to dry the water-washed activated carbon to a constant weight; the dried activated carbon is then sealed and stored for later use.

[0081] In step S1, the step of obtaining the adhesive solution includes:

[0082] Based on 100 parts by weight (specifically 100g) of activated carbon, 5.6 parts by weight (specifically 5.6g) of silica sol, 2.4 parts by weight (specifically 2.4g) of aqueous polyurethane dispersion and 0.05 parts by weight (specifically 0.05g) of silane coupling agent were mixed and stirred continuously in a 60°C water bath for 2-4 hours (specifically 2 hours of stirring at a speed of 50 rpm) to obtain the adhesive solution.

[0083] The silica sol contains 30% SiO2 by mass and has a pH of 9.5.

[0084] The solid content of the aqueous polyurethane dispersion is 40%.

[0085] The silane coupling agent is KH-550.

[0086] In step S2, the water bath heating treatment uses a heating temperature of 65°C and a heating time of 15 minutes.

[0087] In step S3, the curing temperature is 80°C and the curing time is 4 hours.

[0088] Subsequently, it is transferred to a muffle furnace for calcination treatment; the calcination treatment uses a calcination temperature of 250℃ and a calcination time of 1 hour; wherein, the heating rate from the curing temperature to the calcination temperature is 5℃ / min, which effectively relieves the thermal stress of the composite material, prevents cracking, and prevents carbon deposition of the active components.

[0089] Based on Example 1, the present invention also includes Examples 2-5 and Comparative Examples 1-5, and the specific experimental variables are shown in Table 1.

[0090] Samples of the composite materials prepared in Examples 1-5 and Comparative Examples 1-5 were taken for formaldehyde purification tests and toluene purification tests, and the test results are shown in Table 1.

[0091] The formaldehyde purification test conditions are as follows: test temperature is 65℃, relative humidity is 90%, formaldehyde concentration is 25ppm, and gas flow rate is 50mL / min; each composite material is run under the formaldehyde purification test conditions for 100h to test the formaldehyde conversion rate.

[0092] The toluene purification test conditions are as follows: test temperature is 65℃, relative humidity is 90%, toluene concentration is 1000ppm, and gas flow rate is 33mL / min; each composite material is run under the toluene purification test conditions until toluene penetration (that is, when the concentration of toluene passing through the composite material is 5% of its initial concentration of 1000ppm, it is considered toluene penetration), and the toluene penetration adsorption capacity is calculated.

[0093] Table 1. Grouping and test results of Examples 1-5 and Comparative Examples 1-5

[0094]

[0095] From Table 1 and Figures 1-2 Data shows:

[0096] Compared to Comparative Examples 1-5, the composite materials prepared in Examples 1-5 of this invention exhibit a formaldehyde conversion rate of over 85% after 100 hours of continuous formaldehyde purification, and the composite material prepared in Example 1 maintains a 100% formaldehyde conversion rate after 100 hours of continuous formaldehyde purification, demonstrating a significant catalytic decomposition effect on formaldehyde. Regarding toluene purification, the toluene penetration adsorption capacity reaches over 265 mg / g, and the toluene penetration adsorption capacity of the composite material prepared in Example 1 reaches 293 mg / g. (See [link to relevant documentation]). Figure 2 When the toluene purification test time was 2158 min, the composite material was penetrated by toluene, demonstrating excellent adsorption performance for toluene.

[0097] Compared to Example 1, Comparative Example 1 did not use MOF powder, resulting in a significant decrease in the formaldehyde conversion rate and toluene penetration adsorption capacity of the prepared composite material. This is because the absence of MOF powder in Comparative Example 1 caused the composite material to lose molecular-level adsorption sites, leading to a significant decrease in toluene penetration adsorption capacity. Furthermore, the lack of MOF powder meant that the active components could not be confined within the MOF channels, but were directly exposed on the activated carbon surface and within the channels. This made them prone to carbon buildup and deactivation during calcination or reaction, resulting in a significant decrease in the formaldehyde conversion rate.

[0098] Compared to Example 1, Comparative Example 2 did not use an active component, resulting in a significant decrease in the formaldehyde conversion rate and toluene penetration adsorption capacity of the prepared composite material. This is because Comparative Example 2 did not use an active component, meaning the composite material only possesses adsorption properties and lacks catalytic activity, leading to a significant decrease in the formaldehyde conversion rate. The decrease in toluene penetration adsorption capacity is due to the lack of an active component; the adsorbed formaldehyde molecules cannot be degraded and will permanently occupy the adsorption sites of the MOF and activated carbon, blocking the pores that should be used for toluene adsorption, thus reducing the toluene penetration adsorption capacity.

[0099] Compared to Example 1, Comparative Example 3 did not use silica sol, resulting in a significant decrease in the formaldehyde conversion rate and toluene penetration adsorption capacity of the prepared composite material. This is because the absence of silica sol in Comparative Example 3 resulted in a single flexible three-dimensional network bonding structure in the composite material, which did not firmly encapsulate the MOF-active component and was prone to detachment, thus leading to a significant decrease in both the formaldehyde conversion rate and the toluene penetration adsorption capacity.

[0100] Compared to Example 1, Comparative Example 4 did not use a silane coupling agent, resulting in a significant decrease in the formaldehyde conversion rate and toluene penetration adsorption capacity of the prepared composite material. This is because the absence of a silane coupling agent in Comparative Example 4 meant that the dual network bonding structure in the composite material was only physically wrapped around it, resulting in weak encapsulation of the MOF-active component, which easily detached, thus leading to a significant decrease in the formaldehyde conversion rate and toluene penetration adsorption capacity.

[0101] Compared to Example 1, Comparative Example 5 did not use an aqueous polyurethane dispersion, resulting in a significant decrease in the formaldehyde conversion rate and toluene penetration adsorption capacity of the prepared composite material. This is because Comparative Example 5 did not use an aqueous polyurethane dispersion, resulting in a dense and rigid silicon-oxygen-silicon (-Si-O-Si-) three-dimensional network skeleton in the composite material. This skeleton has poor toughness and is prone to cracking, leading to the shedding of the MOF-active component, which in turn causes a significant decrease in the formaldehyde conversion rate and toluene penetration adsorption capacity.

[0102] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing an air-purifying MOF activated carbon composite material, characterized in that, include: Step S1: Under stirring conditions, the MOF-active component suspension is gradually added to the pretreated activated carbon and stirred continuously for 2-4 hours. Subsequently, the adhesive solution is gradually added and stirred continuously for 1-3 hours to obtain the composite slurry; The active components used include Mn, Co, and Ce; The pretreatment includes drying the activated carbon after the strong acid solution has been refluxed. The steps for obtaining the adhesive solution include: Based on 100 parts by weight of activated carbon, 5-6 parts by weight of silica sol, 1-4 parts by weight of aqueous polyurethane dispersion and 0.01-0.07 parts by weight of silane coupling agent are mixed and stirred continuously in a water bath at 60±5℃ for 2-4 hours to obtain the adhesive solution. Step S2: The composite slurry is heated in a water bath to obtain a slurry material; Step S3: Spread the slurry material evenly on the carrier, and then perform curing and calcination treatments in sequence to obtain an air purification MOF activated carbon composite material.

2. The preparation method of the air purification MOF activated carbon composite material as described in claim 1, characterized in that, In step S1, the step of obtaining the MOF-active component suspension includes: Based on 100 parts by mass of activated carbon, 10-15 parts by mass of MOF powder and 1-5 parts by mass of active component are added to an alcohol reagent and ultrasonically dispersed to obtain the MOF-active component suspension. In the active component, the molar ratio of Mn:Co:Ce is 4~5:1~3:1~3; the Mn is derived from manganese salt; the manganese salt includes manganese nitrate; the Co is derived from cobalt salt; the manganese salt includes cobalt nitrate; the Ce is derived from cerium salt; the cerium salt includes cerium nitrate. The volume ratio of the alcohol reagent to the mass ratio of the activated carbon is 100~120mL:100g; The alcohol reagent includes ethanol; The ultrasonic dispersion process uses an ultrasonic power of 200-300W and an ultrasonic time of 10-30min. The MOF powder has a pore size of 1~2 nm.

3. The preparation method of the air purification MOF activated carbon composite material as described in claim 1, characterized in that, In step S1, the reflux treatment includes adding the strong acid solution to 100 parts by mass of activated carbon and refluxing for 4 to 6 hours under stirring conditions. The reflux temperature is 90±5℃; The molar concentration of the strong acid solution is 3 ± 0.5 mol / L; The volume ratio of the strong acid solution to the mass ratio of the activated carbon is 1000~1500mL:100g; The strong acid solution includes a nitric acid solution; The activated carbon includes coconut shell activated carbon; The particle size of the coconut shell activated carbon is 50-100 mesh; The specific surface area of ​​the coconut shell activated carbon is ≥1000 m². 2 / g.

4. The preparation method of the air purification MOF activated carbon composite material as described in claim 1, characterized in that, Between the reflux treatment and the drying treatment, the activated carbon filtered out after the reflux treatment is washed with water until the pH of the washing solution is 6.5~7.0; The drying process uses a drying temperature of 100~120℃ and a drying time of 12~20h to dry the water-washed activated carbon to a constant weight.

5. The preparation method of the air purification MOF activated carbon composite material as described in claim 1, characterized in that, In step S1, the mass percentage of SiO2 in the silica sol is 10% to 30%. The solid content of the aqueous polyurethane dispersion is 20%~40%; The silane coupling agent includes KH-550.

6. The method for preparing the air-purifying MOF activated carbon composite material as described in claim 1, characterized in that, In step S2, the water bath heating treatment uses a heating temperature of 60±5℃ and a heating time of 10~30min.

7. The method for preparing the air-purifying MOF activated carbon composite material as described in claim 1, characterized in that, In step S3, the curing temperature is 80±5℃ and the curing time is 2~5h. The calcination process uses a calcination temperature of 200~270℃ and a calcination time of 1~3h; wherein the heating rate from the curing temperature to the calcination temperature is 3~5℃ / min.

8. An air-purifying MOF activated carbon composite material, characterized in that, It is prepared using the method described in any one of claims 1 to 7 for the preparation of air purification MOF activated carbon composite material.

9. The application of the air-purifying MOF activated carbon composite material as described in claim 8 in the purification of formaldehyde.

10. The application of the air-purifying MOF activated carbon composite material as described in claim 8 in the purification of toluene.

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