Formaldehyde removal filter element material, preparation method thereof and indoor air purifier

Abstract

In order to overcome the problem of insufficient formaldehyde removal efficiency of the existing formaldehyde removal materials, the application provides a preparation method of formaldehyde removal filter core material, which comprises the following operation steps: acrylic ester hard monomer, crosslinking agent, photoinitiator, assistant initiator and surfactant are added into silica sol, tetrabutyl titanate is added, and a premixing solution is obtained; ultraviolet light irradiation curing is carried out, the premixing solution is crosslinked and cured, and a pre-polymer is obtained; the pre-polymer is transferred to hydrothermal reaction at 150 DEG C to 170 DEG C, tetrabutyl titanate is hydrolyzed and converted into nano titanium dioxide, and an intermediate is obtained; the intermediate is washed with water and placed in lye, so that part of the silica in the intermediate is removed, internal pores are formed, the surface of the pores has silanol, and a filter core material precursor is obtained; the filter core material precursor is washed with water and dried, and formaldehyde removal filter core material is obtained. Meanwhile, the application also discloses the formaldehyde removal filter core material prepared by the above preparation method and an indoor air purifier.

Description

Technical Field

[0001] This invention belongs to the field of filter material technology, specifically relating to a formaldehyde removal filter material and its preparation method, and an indoor air purifier. Background Technology

[0002] In the field of indoor air purification, formaldehyde removal technology has always been a research hotspot. Existing formaldehyde removal materials are mainly divided into two types: physical adsorption and catalytic decomposition. Among physical adsorption materials, porous materials such as activated carbon, due to their abundant pore structure and large specific surface area, can adsorb formaldehyde molecules onto their surface through van der Waals forces and other interactions, thereby achieving formaldehyde removal. Catalytic decomposition materials, such as titanium dioxide, with their unique photocatalytic properties, can generate highly oxidizing free radicals under light conditions, decomposing formaldehyde into carbon dioxide and water, thus fundamentally eliminating formaldehyde.

[0003] Because physical adsorption suffers from adsorption saturation and the release of formaldehyde after saturation, existing technologies propose loading titanium dioxide into the pores of activated carbon to form a composite material, aiming to achieve both physical adsorption and catalytic decomposition of formaldehyde, in order to fully utilize the advantages of both technologies. While this design is ingenious, it has significant drawbacks in practical applications. Since titanium dioxide requires ultraviolet light to activate its catalytic function, and activated carbon itself is black, it strongly absorbs and blocks ultraviolet light. This makes it difficult for ultraviolet light to penetrate the outer layer of activated carbon and effectively reach the titanium dioxide loaded in its internal pores. Even with ultraviolet lamps in the environment, the titanium dioxide inside the activated carbon cannot receive sufficient light to produce actual catalytic decomposition, making it difficult for the composite material to achieve the expected formaldehyde removal effect, greatly limiting its promotion and application in the field of air purification. Summary of the Invention

[0004] To address the problem of insufficient formaldehyde removal efficiency in existing formaldehyde removal materials, this invention provides a formaldehyde removal filter material, its preparation method, and an indoor air purifier.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] On one hand, the present invention provides a method for preparing a formaldehyde removal filter material, comprising the following steps:

[0007] Acrylate hard monomers, crosslinking agents, photoinitiators, co-initiators and surfactants were added to silica sol, and tetrabutyl titanate was added under stirring conditions to obtain a premixed solution.

[0008] The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer.

[0009] The prepolymer was transferred to a hydrothermal reaction at 150℃~170℃ to hydrolyze tetrabutyl titanate into nano-titanium dioxide, thus obtaining the intermediate.

[0010] The intermediate is washed with water and then placed in an alkaline solution to remove some of the silica, forming internal pores. The pore surface has silanol groups, thus obtaining the filter material precursor.

[0011] The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

[0012] Optionally, the acrylate hard monomer is selected from methyl methacrylate, and the crosslinking agent is selected from ethylene glycol dimethacrylate.

[0013] Optionally, the silica sol is prepared by mixing tetraethyl orthosilicate, ethanol and water in a volume ratio of 1~3:1~2:0.5~1, adjusting the pH to 3~4, and obtaining silica sol.

[0014] Optionally, the mass fractions of the acrylate hard monomer, the crosslinking agent, the photoinitiator, the co-initiator, the surfactant, the silica sol, and the tetrabutyl titanate are as follows: 80-120 parts acrylate hard monomer, 10-20 parts crosslinking agent, 0.5-3 parts photoinitiator, 0.2-1 parts co-initiator, 2-10 parts surfactant, 40-60 parts silica sol, and 3-15 parts tetrabutyl titanate.

[0015] Optionally, the photoinitiator includes one or more of benzoin and its derivatives and thioxanthone initiators; and / or,

[0016] The co-initiator includes one or more of triethanolamine, azo initiators, peroxide initiators, and persulfate initiators; and / or,

[0017] The surfactant includes one or more of sodium dodecyl sulfate, sodium hexadecyl sulfate, sodium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

[0018] Optionally, the alkaline solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the sodium hydroxide solution is 10%~20%.

[0019] Optionally, the formaldehyde-removing filter material is immersed in an aminosilane coupling agent solution. The aminosilane coupling agent binds to the silanol groups on the surface of the pores through hydrolysis and condensation. After washing and drying, the formaldehyde-removing filter material is obtained.

[0020] In another aspect, the present invention provides a formaldehyde removal filter material prepared by the preparation method described above. The formaldehyde removal filter material includes a transparent polyacrylate porous structure, wherein nano-titanium dioxide is attached to the surface of the pores of the transparent polyacrylate porous structure, and the surface of the pores has silanol groups.

[0021] Optionally, the porous surface of the transparent polyacrylate structure is provided with an amino-modified layer, which is obtained by hydrolytic condensation of an aminosilane coupling agent with silanol groups on the surface of the pores.

[0022] In another aspect, the present invention provides an indoor air purifier, including a fan, a filter element, and an ultraviolet lamp. The filter element includes an outer filter element layer and an inner filter element layer. The outer filter element layer covers the outer periphery of the inner filter element layer. The outer filter element layer is a physical filtration layer. The inner filter element layer is a cylindrical structure prepared from the formaldehyde removal filter element material as described above. The ultraviolet lamp is located inside the cylindrical structure. One end of the cylindrical structure is closed, and the fan is located at the other end of the cylindrical structure.

[0023] According to the preparation method of the formaldehyde removal filter material provided by the present invention, a reaction is carried out by mixing acrylate hard monomers, crosslinking agents and silica sol. The acrylate hard monomers and crosslinking agents form a transparent polyacrylate framework, and the silica sol undergoes hydrolysis and condensation to form nano-silica dispersed in the transparent polyacrylate framework. During subsequent drying, solvent removal forms a porous structure. Simultaneously, alkaline treatment removes the nano-silica, further enriching the pore structure. Meanwhile, a large number of silanol groups remain on the surface of the porous structure. When this formaldehyde removal filter material is used for formaldehyde removal, the porous structure has sufficient pore area to fully contact formaldehyde, and the silanol groups on its surface act as active adsorption sites, forming hydrogen bonds with formaldehyde, thereby achieving physical adsorption of formaldehyde. Furthermore, the polyacrylate framework is a transparent structure that is permeable to ultraviolet light, allowing ultraviolet light to directly irradiate the nano-titanium dioxide on the pore surface, fully stimulating it to generate free radicals. This avoids the problem of light shading rendering the internal nano-titanium dioxide ineffective, effectively improving the catalytic decomposition effect of the nano-titanium dioxide on formaldehyde, achieving a dual effect of "adsorption + catalysis". Detailed Implementation

[0024] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] An embodiment of the present invention provides a method for preparing a formaldehyde removal filter material, comprising the following steps:

[0026] Acrylate hard monomers, crosslinking agents, photoinitiators, co-initiators and surfactants were added to silica sol, and tetrabutyl titanate was added under stirring conditions to obtain a premixed solution.

[0027] The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer.

[0028] The prepolymer was transferred to a hydrothermal reaction at 150℃~170℃ to hydrolyze tetrabutyl titanate into nano-titanium dioxide, thus obtaining the intermediate.

[0029] The intermediate is washed with water and then placed in an alkaline solution to remove some of the silica, forming internal pores. The pore surface has silanol groups, thus obtaining the filter material precursor.

[0030] The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

[0031] The reaction is carried out by mixing acrylate hard monomers, crosslinking agents, and silica sol. The acrylate hard monomers and crosslinking agents form a transparent polyacrylate framework, while the silica sol undergoes hydrolysis and condensation to form nano-silica dispersed within the transparent polyacrylate framework. During subsequent drying, solvent removal creates a porous structure. Alkali treatment further enriches the pore structure by removing the nano-silica. The porous structure retains a large number of silanol groups on its surface. When this formaldehyde-removing filter material is used for formaldehyde removal, the porous structure provides sufficient pore area for contact with formaldehyde, and the silanol groups on its surface act as active adsorption sites, forming hydrogen bonds with formaldehyde to achieve physical adsorption. Simultaneously, the polyacrylate framework is a transparent structure permeable to ultraviolet light, allowing ultraviolet light to directly irradiate the nano-titanium dioxide on the pore surface, fully stimulating it to generate free radicals. This avoids the problem of light shading rendering the internal nano-titanium dioxide ineffective, effectively improving the catalytic decomposition effect of the nano-titanium dioxide on formaldehyde, achieving a dual effect of "adsorption + catalysis".

[0032] In addition, due to the affinity between silica sol and tetrabutyl titanate, after the hydrothermal reaction, the titanium dioxide formed has a certain degree of bonding with silica. During alkaline treatment, the silica is etched, which helps to expose the surface of titanium dioxide, increases the contact area between titanium dioxide and air in the formaldehyde removal filter material, and enhances its reaction area with formaldehyde.

[0033] In some embodiments, the acrylate hard monomer is selected from methyl methacrylate, and the crosslinking agent is selected from ethylene glycol dimethacrylate.

[0034] The methyl methacrylate is used to form a rigid, transparent polymer framework, ensuring the material's light transmittance while improving mechanical strength and preventing filter element deformation during use. The ethylene glycol dimethacrylate has multiple reaction sites, enabling cross-linking reactions of different polymer segments to form a three-dimensional network structure, enhancing material stability, maintaining a regular pore structure during preparation and use, and improving the sustainability of adsorption and catalysis.

[0035] In some embodiments, the silica sol is prepared by mixing tetraethyl orthosilicate, ethanol and water in a volume ratio of 1~3:1~2:0.5~1, adjusting the pH to 3~4, and obtaining silica sol.

[0036] Ethanol, as a good organic solvent, is miscible with water and helps control the formation process of sol. It can slow down the hydrolysis rate of precursors such as tetrabutyl titanate or tetraethyl orthosilicate, and prevent particle agglomeration caused by rapid hydrolysis, thereby helping to form more uniform and finer silica particles.

[0037] By adjusting the silica sol to an acidic pH of 3-4, the hydrolysis process of tetrabutyl titanate can be facilitated, and the subsequent condensation reaction can be promoted. This helps to control the growth rate and size distribution of silica particles. On the other hand, in the subsequent hydrothermal reaction, tetrabutyl titanate first undergoes a hydrolysis reaction to generate titanium alkoxide intermediates. Subsequently, these intermediates will undergo a further condensation reaction to form amorphous titanium oxides. The acidic conditions help to control the hydrolysis rate of tetrabutyl titanate and avoid its excessively rapid hydrolysis, which could lead to particle agglomeration or the production of uneven products.

[0038] In some embodiments, the premixed solution also contains a hindered amine light stabilizer.

[0039] In some embodiments, hydrochloric acid is added to the silica sol to adjust the pH of the silica sol.

[0040] In some embodiments, the mass fractions of the acrylate hard monomer, the crosslinking agent, the photoinitiator, the co-initiator, the surfactant, the silica sol, and the tetrabutyl titanate are as follows: 80-120 parts acrylate hard monomer, 10-20 parts crosslinking agent, 0.5-3 parts photoinitiator, 0.2-1 parts co-initiator, 2-10 parts surfactant, 40-60 parts silica sol, and 3-15 parts tetrabutyl titanate.

[0041] The acrylate hard monomer and the crosslinking agent are used to form a transparent porous framework. When the acrylate hard monomer and the crosslinking agent are in the above weight ratio, it is beneficial to avoid the problems of insufficient crosslinking leading to a loose structure or excessive crosslinking leading to poor pore flow.

[0042] The photoinitiator is the main initiator in this preparation method. It can be fully dispersed with the acrylate hard monomers and crosslinking agents in the system, and then initiate crosslinking and polymerization reactions under ultraviolet light. Unlike emulsion polymerization, which uses an initiator solution to stir and drop the reaction, using a photoinitiator as the main initiator can ensure that the formaldehyde removal filter material obtained by polymerization has high transparency, while stirring polymerization can easily affect the transparency after polymerization.

[0043] The co-initiator is used to further promote the reaction of unreacted monomers and crosslinking agents under subsequent hydrothermal conditions after the polymerization and crosslinking reaction initiated by the photoinitiator, thereby reducing monomer and crosslinking agent residues and improving the mechanical strength of the formaldehyde removal filter material.

[0044] The surfactant is used to promote the full dispersion of the acrylate hard monomer, the crosslinking agent, the photoinitiator, the co-initiator, the silica sol, and the tetrabutyl titanate in the reaction system, thereby improving the compositional uniformity of the formaldehyde removal filter material.

[0045] In some embodiments, the photoinitiator includes one or more of benzoin and its derivatives and thioxanthone initiators.

[0046] In a preferred embodiment, the photoinitiator is selected from benzoin ether.

[0047] In some embodiments, the co-initiator includes one or more of triethanolamine, azo initiators, peroxide initiators, and persulfate initiators.

[0048] In a preferred embodiment, the co-initiator is selected from triethanolamine.

[0049] In some embodiments, the surfactant includes one or more of sodium dodecyl sulfate, sodium hexadecyl sulfate, sodium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

[0050] In a preferred embodiment, the surfactant is selected from sodium dodecyl sulfate.

[0051] In some embodiments, the alkaline solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the sodium hydroxide solution is 10% to 20%.

[0052] A sodium hydroxide solution with a mass concentration of 10% to 20% can achieve a good etching effect on silicon dioxide. At the same time, the etching time can be controlled according to the concentration of the sodium hydroxide solution to leave silanol groups on the surface of the holes.

[0053] In some embodiments, the formaldehyde removal filter material is immersed in an aminosilane coupling agent solution, and the aminosilane coupling agent is hydrolyzed and condensed to bind to the silanol groups on the surface of the pores. After washing and drying, the formaldehyde removal filter material is obtained.

[0054] By treating the formaldehyde removal filter material with an aminosilane coupling agent, amino groups can be attached to the surface of the filter material. The amino groups can undergo a nucleophilic addition reaction with free formaldehyde at room temperature, thereby fixing and eliminating the formaldehyde and achieving the effect of chemically eliminating formaldehyde. In this preparation method, during the initial alkaline treatment, the reaction between the alkaline solution and silica leaves a large number of silanol groups in the pores. The residual silanol groups not only have a hydrogen bond adsorption effect on formaldehyde, but also serve as hydrolysis condensation sites for the aminosilane coupling agent, forming Si-O-Si connections, which helps to ensure the amino loading in the formaldehyde removal filter material.

[0055] Since the reaction between amino groups and formaldehyde is a consumable reaction, the formaldehyde removal filter material can be retreated with an aminosilane coupling agent after a period of use to restore its amino loading.

[0056] In a preferred embodiment, the aminosilane coupling agent is selected from 3-aminopropyltrimethoxysilane.

[0057] Another embodiment of the present invention provides a formaldehyde removal filter material prepared by the preparation method described above. The formaldehyde removal filter material includes a transparent polyacrylate porous structure, wherein nano-titanium dioxide is attached to the surface of the pores of the transparent polyacrylate porous structure, and the surface of the pores has silanol groups.

[0058] In some embodiments, an amino-modified layer is disposed on the surface of the pores of the transparent polyacrylate porous structure, the amino-modified layer being obtained by hydrolytic condensation of an aminosilane coupling agent with silanol groups on the pore surface.

[0059] Another embodiment of the present invention provides an indoor air purifier, including a fan, a filter element, and an ultraviolet lamp. The filter element includes an outer filter element layer and an inner filter element layer. The outer filter element layer covers the outer periphery of the inner filter element layer. The outer filter element layer is a physical filtration layer. The inner filter element layer is a cylindrical structure prepared from the formaldehyde removal filter element material as described above. The ultraviolet lamp is located inside the cylindrical structure. One end of the cylindrical structure is closed, and the fan is located at the other end of the cylindrical structure.

[0060] By providing an outer filter layer outside the inner layer of the filter element, the air entering the inner layer of the filter element can be physically filtered, thereby reducing the number of dust and other particles entering the inner layer of the filter element, reducing the coverage of particles on the pores of the formaldehyde removal filter element material, and thus extending the service life and formaldehyde removal effect of the formaldehyde removal filter element material.

[0061] The present invention will be further illustrated by the following examples.

[0062] Example 1

[0063] This embodiment illustrates the formaldehyde removal filter material and its preparation method disclosed in this invention, including the following steps:

[0064] Tetraethyl orthosilicate, ethanol, and water were mixed in a volume ratio of 2:1.5:0.5, and the pH was adjusted to 4 to obtain silica sol.

[0065] By weight, 100 parts of methyl methacrylate, 15 parts of ethylene glycol dimethacrylate, 2 parts of benzoin ether, 0.5 parts of triethanolamine and 5 parts of sodium dodecyl sulfate were added to 50 parts of silica sol, and 6 parts of tetrabutyl titanate were added under stirring to obtain a premixed solution.

[0066] The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer.

[0067] The prepolymer was transferred to a hydrothermal reaction at 160°C, which hydrolyzed tetrabutyl titanate into nano-titanium dioxide to obtain an intermediate.

[0068] The intermediate was washed with water and then placed in a 15wt% sodium hydroxide solution for 3 hours to remove some of the silica, forming internal pores. The pore surface has silanol groups, thus obtaining the filter material precursor.

[0069] The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

[0070] The formaldehyde removal filter material was immersed in a 5 wt% solution of 3-aminopropyltrimethoxysilane for 4 hours. The 3-aminopropyltrimethoxysilane was hydrolyzed and condensed to bind to the silanol groups on the surface of the pores. After washing and drying, the formaldehyde removal filter material was obtained.

[0071] Example 2

[0072] This embodiment illustrates the formaldehyde removal filter material and its preparation method disclosed in this invention, including the following steps:

[0073] Tetraethyl orthosilicate, ethanol, and water were mixed in a volume ratio of 2:1.5:0.5, and the pH was adjusted to 3 to obtain silica sol.

[0074] By weight, 80 parts of methyl methacrylate, 20 parts of ethylene glycol dimethacrylate, 1 part of benzoin ether, 1 part of triethanolamine and 4 parts of sodium dodecyl sulfate were added to 40 parts of silica sol, and 15 parts of tetrabutyl titanate were added under stirring to obtain a premixed solution.

[0075] The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer.

[0076] The prepolymer was transferred to a hydrothermal reaction at 160°C, which hydrolyzed tetrabutyl titanate into nano-titanium dioxide to obtain an intermediate.

[0077] The intermediate was washed with water and then placed in a 15wt% sodium hydroxide solution for 3 hours to remove some of the silica, forming internal pores. The pore surface has silanol groups, thus obtaining the filter material precursor.

[0078] The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

[0079] The formaldehyde removal filter material was immersed in a 5 wt% solution of 3-aminopropyltrimethoxysilane for 4 hours. The 3-aminopropyltrimethoxysilane was hydrolyzed and condensed to bind to the silanol groups on the surface of the pores. After washing and drying, the formaldehyde removal filter material was obtained.

[0080] Example 3

[0081] This embodiment illustrates the formaldehyde removal filter material and its preparation method disclosed in this invention, including the following steps:

[0082] Tetraethyl orthosilicate, ethanol, and water were mixed in a volume ratio of 1:2:1, and the pH was adjusted to 3 to obtain silica sol.

[0083] By weight, 120 parts of methyl methacrylate, 10 parts of ethylene glycol dimethacrylate, 3 parts of benzoin ether, 1 part of triethanolamine and 8 parts of sodium dodecyl sulfate were added to 60 parts of silica sol, and 5 parts of tetrabutyl titanate were added under stirring to obtain a premixed solution.

[0084] The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer.

[0085] The prepolymer was transferred to a hydrothermal reaction at 160°C, which hydrolyzed tetrabutyl titanate into nano-titanium dioxide to obtain an intermediate.

[0086] The intermediate was washed with water and then placed in a 15wt% sodium hydroxide solution for 3 hours to remove some of the silica, forming internal pores. The pore surface has silanol groups, thus obtaining the filter material precursor.

[0087] The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

[0088] The formaldehyde removal filter material was immersed in a 5 wt% solution of 3-aminopropyltrimethoxysilane for 4 hours. The 3-aminopropyltrimethoxysilane was hydrolyzed and condensed to bind to the silanol groups on the surface of the pores. After washing and drying, the formaldehyde removal filter material was obtained.

[0089] Example 4

[0090] This embodiment illustrates the formaldehyde removal filter material and its preparation method disclosed in this invention, including the following steps:

[0091] Tetraethyl orthosilicate, ethanol, and water were mixed in a volume ratio of 2:1.5:0.5, and the pH was adjusted to 4 to obtain silica sol.

[0092] By weight, 100 parts of methyl methacrylate, 15 parts of ethylene glycol dimethacrylate, 2 parts of benzoin ether, 0.5 parts of triethanolamine and 5 parts of sodium dodecyl sulfate were added to 50 parts of silica sol, and 6 parts of tetrabutyl titanate were added under stirring to obtain a premixed solution.

[0093] The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer.

[0094] The prepolymer was transferred to a hydrothermal reaction at 160°C, which hydrolyzed tetrabutyl titanate into nano-titanium dioxide to obtain an intermediate.

[0095] The intermediate was washed with water and then placed in a 15wt% sodium hydroxide solution for 3 hours to remove some of the silica, forming internal pores. The pore surface has silanol groups, thus obtaining the filter material precursor.

[0096] The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

[0097] Comparative Example 1

[0098] This comparative example is used to illustrate the formaldehyde removal filter material and its preparation method disclosed in this invention, and includes the following steps:

[0099] By weight, 100 parts of methyl methacrylate, 15 parts of ethylene glycol dimethacrylate, 2 parts of benzoin ether, 0.5 parts of triethanolamine and 5 parts of sodium dodecyl sulfate were added to 50 parts of solvent. Under stirring, 6 parts of tetrabutyl titanate were added to obtain a premixed solution. The solvent was a mixture of ethanol and water with a volume ratio of 1.5:0.5.

[0100] The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer.

[0101] The prepolymer was transferred to a hydrothermal reaction at 160°C, which hydrolyzed tetrabutyl titanate into nano-titanium dioxide to obtain an intermediate.

[0102] The intermediate was washed with water and then placed in a 15wt% sodium hydroxide solution for 3 hours to obtain the filter material precursor.

[0103] The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

[0104] The formaldehyde removal filter material was immersed in a 5 wt% solution of 3-aminopropyltrimethoxysilane for 4 hours. The 3-aminopropyltrimethoxysilane was hydrolyzed and condensed to bind to the surface of the pores. After washing and drying, the formaldehyde removal filter material was obtained.

[0105] Comparative Example 2

[0106] This comparative example is used to illustrate the formaldehyde removal filter material and its preparation method disclosed in this invention, and includes the following steps:

[0107] Tetraethyl orthosilicate, ethanol, and water were mixed in a volume ratio of 2:1.5:0.5, and the pH was adjusted to 4 to obtain silica sol.

[0108] By weight, 100 parts of methyl methacrylate, 15 parts of ethylene glycol dimethacrylate, 2 parts of benzoin ether, 0.5 parts of triethanolamine and 5 parts of sodium dodecyl sulfate were added to 50 parts of silica sol to obtain a premixed solution.

[0109] The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer.

[0110] The prepolymer was transferred to a hydrothermal reaction at 160°C to obtain an intermediate.

[0111] The intermediate was washed with water and then placed in a 15wt% sodium hydroxide solution for 3 hours to remove some of the silica, forming internal pores. The pore surface has silanol groups, thus obtaining the filter material precursor.

[0112] The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

[0113] The formaldehyde removal filter material was immersed in a 5 wt% solution of 3-aminopropyltrimethoxysilane for 4 hours. The 3-aminopropyltrimethoxysilane was hydrolyzed and condensed to bind to the silanol groups on the surface of the pores. After washing and drying, the formaldehyde removal filter material was obtained.

[0114] Performance testing

[0115] The formaldehyde removal filter material prepared above was subjected to the following performance tests:

[0116] Adopting 1m 3 The test chamber is equipped with air inlets and outlets and a formaldehyde monitoring device. Paraformaldehyde is placed in a heating device and pyrolyzed at 120℃. Nitrogen carrier gas is then introduced into the test chamber at a flow rate of 100 mL / min. The flow rate is controlled to maintain the formaldehyde concentration in the test chamber at 1.0 ± 0.1 mg / m³. 3 After assembling the formaldehyde removal filter material with the fan and ultraviolet lamp, place it in the test chamber, turn on the fan and ultraviolet lamp, and record the formaldehyde concentration in the chamber at 0 min, 10 min, 30 min and 60 min respectively.

[0117] The test results are entered into Table 1.

[0118] Table 1

[0119]

[0120] As can be seen from the test results in Table 1, the formaldehyde removal filter material prepared by the preparation method provided by the present invention has abundant pores, which can promote full contact between the formaldehyde in the airflow and the pore surface of the formaldehyde removal filter material. At the same time, the formaldehyde removal filter material has good physical adsorption, catalytic decomposition and chemical reaction elimination effects on formaldehyde, and can quickly remove formaldehyde from the air.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a formaldehyde-removing filter material, characterized in that, The following steps are included: Acrylic hard monomers, crosslinking agents, photoinitiators, co-initiators and surfactants are added to silica sol, and tetrabutyl titanate is added under stirring conditions to obtain a premix. The acrylate hard monomers are selected from methyl methacrylate, and the crosslinking agent is selected from ethylene glycol dimethacrylate. The premixed liquid is cured by ultraviolet light irradiation to crosslink and cure, thus obtaining a prepolymer. The prepolymer was transferred to a hydrothermal reaction at 150℃~170℃ to hydrolyze tetrabutyl titanate into nano-titanium dioxide, thus obtaining the intermediate. The intermediate is washed with water and then placed in an alkaline solution to remove some of the silica, forming internal pores. The pore surface has silanol groups, thus obtaining the filter material precursor. The filter material precursor is washed and dried to obtain the formaldehyde removal filter material.

2. The method for preparing the formaldehyde removal filter material according to claim 1, characterized in that, The silica sol is prepared by mixing tetraethyl orthosilicate, ethanol and water in a volume ratio of 1~3:1~2:0.5~1, adjusting the pH to 3~4, and obtaining silica sol.

3. The method for preparing the formaldehyde-removing filter material according to claim 1, characterized in that, The mass fractions of the acrylate hard monomer, the crosslinking agent, the photoinitiator, the co-initiator, the surfactant, the silica sol, and the tetrabutyl titanate are as follows: 80-120 parts acrylate hard monomer, 10-20 parts crosslinking agent, 0.5-3 parts photoinitiator, 0.2-1 parts co-initiator, 2-10 parts surfactant, 40-60 parts silica sol, and 3-15 parts tetrabutyl titanate.

4. The method for preparing the formaldehyde-removing filter material according to claim 1, characterized in that, The photoinitiator includes one or more of benzoin and its derivatives and thioxanthone initiators; and / or, The co-initiator includes one or more of triethanolamine, azo initiators, peroxide initiators, and persulfate initiators; and / or, The surfactant includes one or more of sodium dodecyl sulfate, sodium hexadecyl sulfate, sodium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

5. The method for preparing the formaldehyde-removing filter material according to claim 1, characterized in that, The alkaline solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the sodium hydroxide solution is 10%~20%.

6. The method for preparing the formaldehyde-removing filter material according to claim 1, characterized in that, The formaldehyde removal filter material is immersed in an aminosilane coupling agent solution. The aminosilane coupling agent binds to the silanol groups on the surface of the pores through hydrolysis and condensation. After washing and drying, the formaldehyde removal filter material is obtained.

7. The formaldehyde-removing filter material prepared by the preparation method according to any one of claims 1 to 6, characterized in that, The formaldehyde removal filter material includes a transparent polyacrylate porous structure, with nano-titanium dioxide attached to the surface of the pores of the transparent polyacrylate porous structure, and the pore surface having silanol groups.

8. The formaldehyde removal filter material according to claim 7, characterized in that, The porous structure of the transparent polyacrylate has an amino-modified layer on its pore surface, which is obtained by hydrolytic condensation of an aminosilane coupling agent with silanol groups on the pore surface.

9. An indoor air purifier, characterized in that, The device includes a fan, a filter element, and an ultraviolet lamp. The filter element comprises an outer layer and an inner layer, with the outer layer covering the outer periphery of the inner layer. The outer layer is a physical filtration layer, and the inner layer is a cylindrical structure prepared from the formaldehyde removal filter material as described in claim 7 or 8. The ultraviolet lamp is located inside the cylindrical structure, one end of the cylindrical structure is closed, and the fan is located at the other end of the cylindrical structure.

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