Air filtering material, preparation method thereof and air purification device

Abstract

The invention discloses an air filtering material, a preparation method thereof and an air purifying device.The method comprises the steps that chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide are used for preparing an intermediate product with a core-shell structure, then the intermediate product is added into a second mixed solvent, and under the condition of continuous stirring, the second mixed solvent is added into the first mixed solvent for stirring, and the air filtering material is obtained. Sequentially adding dopamine hydrochloride and a catalyst, and filtering, washing and drying a product after reaction to obtain an adsorbent; and preparing the air filtering material from the adsorbent, a polymer and an additive through a melt-blowing process and a flat pressing process. The air filtering material provided by the invention is applied to adsorption of pollutants in air and has good formaldehyde adsorption performance.

Description

Technical Field

[0001] The present invention relates to the field of air purification, and in particular to an air filter material and a preparation method thereof, and an air purification device. Background Art

[0002] As environmental pressures grow, people's awareness of environmental protection is gradually strengthening, and attention to indoor air quality is increasing. Air pollutants, such as formaldehyde and inhalable particulate matter, have attracted widespread attention as key factors affecting the health and comfort of people's living environments. Formaldehyde, in particular, is a volatile organic toxic substance that can cause harm to the human body.

[0003] Currently, the main methods for treating indoor formaldehyde include physical adsorption, chemical adsorption, and photocatalytic oxidation. Physical adsorption is the most common method, and various adsorption materials are used to remove formaldehyde, such as porous carbon materials, calcium carbonate, and metal particles. Among porous carbon materials, activated carbon is the most commonly used adsorption material for formaldehyde, but its actual adsorption effect is poor.

[0004] In related technologies, in order to improve the adsorption performance of activated carbon for formaldehyde, methods such as adding titanium dioxide to achieve photocatalytic oxidation or loading organic amine substances are often used. However, the adsorption effects of these methods still need to be further improved. Summary of the Invention

[0005] In view of at least one technical problem in the prior art, the object of the present invention is to provide an air filter material and a preparation method thereof, and an air purification device.

[0006] In order to solve the above technical problems, on the one hand, the present invention provides a method for preparing an air filter material, comprising the following steps:

[0007] placing chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide in a first mixed solution and continuously stirring the solution; filtering the product after the reaction and washing and drying the product to obtain an intermediate product having a core-shell structure;

[0008] The intermediate product is added to a second mixed solvent, and dopamine hydrochloride and a catalyst are added in sequence under continuous stirring. After the reaction, the product is filtered, washed, and dried to obtain an adsorbent;

[0009] The adsorbent, polymer and additive are subjected to a melt-blowing process and a flat-pressing process to prepare an air filter material.

[0010] Preferably, the mass ratio of chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide is (2-3):(4-5):(1-2); and / or,

[0011] The mass ratio of the intermediate product, dopamine hydrochloride and catalyst is (2-3):(1-2):(0.5-1); and / or,

[0012] The mass ratio of the adsorbent, the polymer and the additive is (10-20):(350-410):(5-10).

[0013] Preferably, the first mixed solution comprises anhydrous 1,4-dioxane and a 5% aqueous acetic acid solution; and the process of placing chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide in the first mixed solution and continuously stirring is specifically as follows:

[0014] Chloromethyl salicylaldehyde was added to anhydrous 1,4-dioxane, and then a 5% acetic acid aqueous solution was added for ultrasonication, and then polyethyleneimine and zirconium dioxide were added and stirred continuously until the reaction was completed.

[0015] Preferably, the process of placing in the first mixed solution and continuously stirring satisfies at least one of the following conditions:

[0016] The volume ratio of anhydrous 1,4-dioxane and acetic acid aqueous solution is (2-3):(3-4);

[0017] The mass volume ratio of the chloromethyl salicylaldehyde and anhydrous 1,4-dioxane is (2-3) g: (20-30) mL;

[0018] The time for adding 5% acetic acid aqueous solution and performing ultrasound is 10 minutes to 60 minutes;

[0019] The time for adding polyethyleneimine and zirconium dioxide and continuously stirring is 1 hour to 3 hours.

[0020] Preferably, the preparation method of the air filter material satisfies at least one of the following conditions:

[0021] The second mixed solvent is any one of dioxane and butanol, dioxane and glacial acetic acid, dichloromethane and ethyl acetate;

[0022] The catalyst is any one of trifluoroacetic acid, benzothiazole disulfide or tetraethyl silicate;

[0023] The additive is any one of ethylene diethyl ether, di-sec-butylamine, and cyclopropaneamide;

[0024] The stirring time in the second mixed solvent is 50 min to 60 min.

[0025] Preferably, the polymer is a blend of polylactic acid and cellulose acetate;

[0026] In the melt-blowing process, the mass ratio of polylactic acid to cellulose acetate is (20-24):(15-17).

[0027] Preferably, the process of preparing the air filter material by melt-blowing and flat-pressing the adsorbent, polymer and additive comprises:

[0028] The polymer, adsorbent and additives are added to the twin-screw extruder. After heating, melting and extrusion, the melt is extruded from the spinneret holes to form ultra-fine filament fibers, which are condensed on the drum-type fiber receiver to form a melt-blown fiber web.

[0029] The collected meltblown fiber web is pressed flatly and then consolidated into a film to obtain an air filter material.

[0030] Preferably, the temperatures of zones 1 to 5 of the twin-screw extruder used are 130°C to 140°C, 160°C to 170°C, 180°C to 190°C, 200°C to 210°C, and 220°C to 230°C, respectively; the screw speed is 50r / min to 70r / min; the feeding speed is 8r / min to 9r / min; and the receiving distance is 5cm to 25cm.

[0031] And / or, the obtained meltblown fiber web has an average diameter of 2 μm to 7 μm and an average pore size of 25 μm to 35 μm.

[0032] Preferably, before the step of preparing the intermediate product having a core-shell structure, the method further comprises:

[0033] Dissolve salicylaldehyde in deionized water, add ethanol and sonicate, then add glycerol and continue sonicating to mix evenly to obtain a salicylaldehyde solution;

[0034] Trioxymethylene is added to the salicylaldehyde solution and stirred continuously, and then 30% hydrochloric acid is added thereto and stirred continuously until the reaction is completed. A solid product is obtained by suction filtration and dried to obtain chloromethyl salicylaldehyde.

[0035] Preferably, the process for preparing the intermediate product having a core-shell structure satisfies at least one of the following conditions:

[0036] The mass ratio of salicylaldehyde to trioxymethylene is (0.5-1.5):(2-3);

[0037] The volume ratio of the deionized water, ethanol, glycerol and hydrochloric acid is (1-2):(8-9):(2-3):(1-2);

[0038] The mass volume ratio of salicylaldehyde to glycerol is: (0.5-1.5) g: (20-30) mL;

[0039] The ultrasonic time after adding ethanol is 15min to 1h;

[0040] The time of adding the salicylaldehyde solution and stirring continuously is 20 minutes to 60 minutes;

[0041] The time for adding 30% hydrochloric acid and continuously stirring is 30 minutes to 60 minutes.

[0042] On the other hand, the present invention also provides an air filter material, which is prepared by the method described in the above technical solution and is used for adsorbing pollutants in the air.

[0043] On the other hand, the present invention also provides an air purification device, which includes the air filter material described in the above technical solution.

[0044] The air filter material, preparation method thereof, and air purification device of the present invention have at least the following beneficial effects:

[0045] In an embodiment of the present invention, an intermediate product having a core-shell structure is prepared by combining chloromethyl salicylaldehyde, polyethyleneimine, and zirconium dioxide. This intermediate product is then added to a second mixed solvent. Dopamine hydrochloride and a catalyst are then added sequentially under continuous stirring. After the reaction, the product is filtered, washed, and dried to obtain the adsorbent ZrO2@CMSA-PEI-DA. The adsorbent, polymer, and additive are then melt-blown and flat-pressed to produce an air filter material. As the prepared air filter material is a membrane material, its high specific surface area provides more adsorption sites. The air filter material obtained by adding the synthesized adsorbent to the melt-blown process of polylactic acid and cellulose acetate has excellent adsorption capabilities for airborne pollutants, particularly formaldehyde.

[0046] Furthermore, the adsorbent ZrO2@CMSA-PEI-DA in this invention imparts superior mechanical properties to the air filter material, making it resistant to breakage and highly stable. Furthermore, it imparts hydrolysis resistance and swelling resistance, enabling the manufacture of durable, long-lasting filter materials for adsorbing airborne pollutants. Furthermore, the polylactic acid and cellulose acetate used in the meltblown process are both biodegradable and environmentally friendly materials, effectively preventing secondary environmental contamination from the adsorbed filter membrane.

[0047] Furthermore, the preparation method of the present invention features a simple process, mild conditions, and easy control. The raw materials used are all non-toxic or low-toxic, resulting in low raw material consumption and low cost during the reaction. Furthermore, no toxic byproducts are generated, making it an environmentally friendly synthesis method. Furthermore, the prepared air filter material has a high functional group content and maintains good morphology and strength, making it suitable for use in the field of air purification. Furthermore, the prepared air filter material also has application prospects in functionalized textiles, water purification, and chemical separation and extraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 This is a flow chart of the steps of a method for preparing an air filter material provided by the present invention;

[0050] Figure 2 is a scanning electron microscope image of the adsorbent prepared in Example 3 of the present invention;

[0051] Figure 3 This is a scanning electron microscope image of the air filter material prepared in Example 3 of the present invention;

[0052] Figure 4 This is a photo of the fiber membrane of the air filter material prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0054] The present invention provides a method for preparing an air filter material, such as Figure 1 As shown, the following steps are included.

[0055] S1, placing chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide in a first mixed solution and continuously stirring, filtering and washing the product after the reaction to obtain an intermediate product having a core-shell structure;

[0056] S2, adding the intermediate product to a second mixed solvent, and adding dopamine hydrochloride and a catalyst in sequence under continuous stirring. After the reaction, the product is filtered, washed, and dried to obtain an adsorbent;

[0057] S3. The adsorbent, polymer and additive are subjected to a melt-blowing process and a flat-pressing process to prepare an air filter material.

[0058] Preferably, in step S1, the mass ratio of chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide is (2-3):(4-5):(1-2); and / or,

[0059] In step S2, the mass ratio of the intermediate product, dopamine hydrochloride and catalyst is (2-3):(1-2):(0.5-1); and / or,

[0060] In step S3, the mass ratio of the adsorbent, polymer and additive is (10-20):(350-410):(5-10).

[0061] Preferably, in step S1, the first mixed solution comprises anhydrous 1,4-dioxane and a 5% aqueous acetic acid solution; and the process of placing chloromethyl salicylaldehyde, polyethyleneimine, and zirconium dioxide in the first mixed solution and continuously stirring is specifically as follows:

[0062] Chloromethyl salicylaldehyde was added to anhydrous 1,4-dioxane, and then a 5% acetic acid aqueous solution was added for ultrasonication, and then polyethyleneimine and zirconium dioxide were added and stirred continuously until the reaction was completed.

[0063] Preferably, the process of placing in the first mixed solution and continuously stirring satisfies at least one of the following conditions:

[0064] The volume ratio of anhydrous 1,4-dioxane and acetic acid aqueous solution is (2-3):(3-4);

[0065] The mass volume ratio of the chloromethyl salicylaldehyde and anhydrous 1,4-dioxane is (2-3) g: (20-30) mL;

[0066] The time for adding 5% acetic acid aqueous solution for ultrasonication is 10 minutes to 60 minutes, preferably 20 minutes;

[0067] The time for continuously stirring the adding polyethyleneimine and zirconium dioxide is 1 hour to 3 hours, preferably 1.5 hours to 2 hours.

[0068] Preferably, the preparation method of the air filter material satisfies at least one of the following conditions:

[0069] The second mixed solvent is any one of dioxane and butanol, dioxane and glacial acetic acid, dichloromethane and ethyl acetate;

[0070] The catalyst is any one of trifluoroacetic acid, benzothiazole disulfide or tetraethyl silicate;

[0071] The additive is any one of ethylene diethyl ether, di-sec-butylamine, and cyclopropaneamide;

[0072] The continuous stirring time in the second mixed solvent is 30 min to 80 min, preferably 50 min to 60 min.

[0073] Preferably, the polymer is a blend of polylactic acid and cellulose acetate. In the melt-blowing process, the mass ratio of polylactic acid to cellulose acetate is (20-24):(15-17).

[0074] Preferably, in the melt-blowing process, the proportions of the substances are as follows: polylactic acid 200g-240g, cellulose acetate 150g-170g, adsorbent 10g-20g, and additive 5g-10g.

[0075] Preferably, the process of preparing the air filter material by melt-blowing and flat-pressing the adsorbent, polymer and additive comprises:

[0076] The polymer, adsorbent and additives are added to the twin-screw extruder. After heating, melting and extrusion, the melt is extruded from the spinneret holes to form ultra-fine filament fibers, which are condensed on the drum-type fiber receiver to form a melt-blown fiber web.

[0077] The collected meltblown fiber web is pressed flatly and then consolidated into a film to obtain an air filter material.

[0078] Preferably, the temperatures of zones 1 to 5 of the twin-screw extruder used are 130°C to 140°C, 160°C to 170°C, 180°C to 190°C, 200°C to 210°C, and 220°C to 230°C, respectively; the screw speed is 50r / min to 70r / min; the feeding speed is 8r / min to 9r / min; and the receiving distance is 5cm to 25cm.

[0079] And / or, the obtained meltblown fiber web has an average diameter of 2 μm to 7 μm and an average pore size of 25 μm to 35 μm.

[0080] Preferably, before the step of preparing the intermediate product having a core-shell structure, the method further comprises:

[0081] Dissolve salicylaldehyde in deionized water, add ethanol and sonicate, then add glycerol and continue sonicating to mix evenly to obtain a salicylaldehyde solution;

[0082] Trioxymethylene is added to the salicylaldehyde solution and stirred continuously, and then 30% hydrochloric acid is added thereto and stirred continuously until the reaction is completed. A solid product is obtained by suction filtration and dried to obtain chloromethyl salicylaldehyde.

[0083] Preferably, the process for preparing the intermediate product having a core-shell structure satisfies at least one of the following conditions:

[0084] The mass ratio of salicylaldehyde to trioxymethylene is (0.5-1.5):(2-3);

[0085] The volume ratio of the deionized water, ethanol, glycerol and hydrochloric acid is (1-2):(8-9):(2-3):(1-2);

[0086] The mass volume ratio of salicylaldehyde to glycerol is: (0.5-1.5) g: (20-30) mL;

[0087] The ultrasonic time after adding ethanol is 15min to 1h;

[0088] The time of adding the salicylaldehyde solution and stirring continuously is 20 min to 60 min, preferably 20 min to 30 min;

[0089] The time for adding 30% hydrochloric acid and continuously stirring is 30 minutes to 60 minutes, preferably 30 minutes to 40 minutes.

[0090] As a preferred overall solution, an embodiment of the present invention provides a method for preparing an air filter material, comprising the following steps:

[0091] a) Dissolve 0.5-1.5 g of salicylaldehyde in 10-20 mL of deionized water, add 80-90 mL of ethanol, and sonicate for 30 minutes. Then, add 20-30 mL of glycerol and continue sonicating for 10 minutes. Add 2-3 g of trioxymethylene to the solution and stir continuously for 20-30 minutes. Then, add 10-20 mL of 30% hydrochloric acid and stir continuously for 30-40 minutes. After the reaction is complete, filter the resulting solid product and dry it in an oven at 40°C for 5 hours to obtain chloromethyl salicylaldehyde (CMSA).

[0092] b) 2-3 g of CMSA was added to 20 mL-30 mL of anhydrous 1,4-dioxane, and then 30 mL-40 mL of 5% acetic acid aqueous solution was added and ultrasonicated for 20 min. Then 4 g-5 g of polyethyleneimine (PEI) and 1 g-2 g of zirconium dioxide (ZrO2) were added and stirred continuously for 1.5 h-2 h. After the reaction was completed, the supernatant was removed and the solid at the bottom was washed with 20 mL of anhydrous ethanol for 30 s. The obtained product was dried in an oven at 40 ° C for 5 h to obtain ZrO2@CMSA-PEI, i.e., the intermediate product.

[0093] c) Add 2-3 g of the above-mentioned ZrO2@CMSA-PEI to 20-40 mL of the binary solvent. While stirring continuously for 50-60 minutes, 1-2 g of dopamine hydrochloride and 0.5-1 g of the catalyst are added sequentially. After the reaction is completed, the supernatant is removed, and the resulting product is washed with 20 mL of anhydrous ethanol for 30 seconds. After washing, it is dried in a 40°C oven for 5 hours to obtain ZrO2@CMSA-PEI-DA, the adsorbent.

[0094] d) adding the polymer, adsorbent and additive into a twin-screw extruder in a certain proportion, obtaining ultrafine fibers by melt-blowing, and then obtaining air filter materials by flat pressing.

[0095] In another aspect, the present invention further provides an air filter material, the air filter material being prepared by the method described in the above technical solution, and the air filter material being used for adsorbing pollutants in the air. Exemplary pollutants include, but are not limited to, one or more of formaldehyde, ammonia, and trimethylamine.

[0096] On the other hand, the present invention also provides an air purification device, comprising the air filter material described in the above technical solution. The air purification device may include but is not limited to an air purifier, an air conditioner with integrated air purification function, or other electrical devices.

[0097] The following is further described in detail with reference to specific embodiments to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0098] Example 1

[0099] (1) Synthesis of adsorbent:

[0100] 0.5 g of salicylaldehyde was dissolved in 10 mL of deionized water, 80 mL of ethanol was added, and the mixture was ultrasonicated for 30 minutes. 20 mL of glycerol was then added and ultrasonicated for another 10 minutes. 2 g of trioxymethylene was added to the solution and stirred continuously for 20 minutes. Then, 10 mL of 30% hydrochloric acid was added and stirred continuously for 30 minutes. After the reaction was complete, the resulting solid product was filtered and dried in a 40°C oven for 5 hours to obtain chloromethyl salicylaldehyde (CMSA).

[0101] 2 g of CMSA was added to 20 mL of anhydrous 1,4-dioxane, and then 30 mL of 5% acetic acid aqueous solution was added and ultrasonicated for 20 min. Then 4 g of polyethyleneimine (PEI) and 1 g of ZrO2 were added and stirred continuously for 1.5 h. After the reaction was completed, the supernatant was removed and the solid at the bottom was washed with 20 mL of anhydrous ethanol for 30 s. The obtained product was dried in an oven at 40 ° C for 5 h to obtain the intermediate product ZrO2@CMSA-PEI.

[0102] 2g of the intermediate product, ZrO2@CMSA-PEI, was added to a binary solvent consisting of 10mL of dioxane and 10mL of butanol. Under constant stirring for 50 minutes, 1g of dopamine hydrochloride and 0.5g of the catalyst, benzothiazole disulfide, were added sequentially. After the reaction, the supernatant was removed, and the resulting product was washed with 20mL of anhydrous ethanol for 30 seconds. After washing, it was dried in a 40°C oven for 5 hours to obtain the adsorbent ZrO2@CMSA-PEI-DA.

[0103] (2) Preparation of air filter materials:

[0104] 200g of polylactic acid, 150g of cellulose acetate, 10g of adsorbent ZrO2@CMSA-PEI-DA, and 5g of ethylene diethyl ester were mixed evenly and added to a twin-screw extruder. The temperatures of zones 1 to 5 of the twin-screw extruder were 130°C, 160°C, 180°C, 200°C, and 220°C, respectively; the screw speed was 50r / min; the feeding speed was 8r / min; the receiving distance was 5cm, and ultrafine fibers were obtained through a melt-blowing process, and then a fiber membrane, i.e., an air filter material, was obtained after flat pressing.

[0105] Example 2

[0106] (1) Synthesis of adsorbent:

[0107] 1.0 g of salicylaldehyde was dissolved in 15 mL of deionized water, followed by the addition of 85 mL of ethanol and ultrasonication for 30 minutes. 25 mL of glycerol was then added and ultrasonication continued for 10 minutes. 2.5 g of trioxymethylene was added to the solution and stirred continuously for 25 minutes. Then, 15 mL of 30% hydrochloric acid was added and stirred continuously for 35 minutes. After the reaction was complete, the resulting solid product was filtered and dried in a 40°C oven for 5 hours to yield chloromethyl salicylaldehyde (CMSA).

[0108] 2.5 g of CMSA was added to 25 mL of anhydrous 1,4-dioxane, and then 35 mL of 5% acetic acid aqueous solution was added and ultrasonicated for 20 min. Then 4.5 g of polyethyleneimine (PEI) and 1.5 g of ZrO2 were added and stirred continuously for 1.7 h. After the reaction was completed, the supernatant was removed and the solid at the bottom was washed with 20 mL of anhydrous ethanol for 30 s. The obtained product was dried in an oven at 40 ° C for 5 h to obtain the intermediate product ZrO2@CMSA-PEI.

[0109] 2.5g of the above-mentioned ZrO2@CMSA-PEI was added to a binary solvent consisting of 15mL of dioxane and 15mL of butanol. Under constant stirring for 55 minutes, 1.5g of dopamine hydrochloride and 0.7g of the catalyst benzothiazole disulfide were added sequentially. After the reaction, the supernatant was removed, and the resulting product was washed with 20mL of anhydrous ethanol for 30 seconds. After washing, it was dried in a 40°C oven for 5 hours to obtain the adsorbent ZrO2@CMSA-PEI-DA.

[0110] (2) Preparation of air filter materials:

[0111] 220g of polylactic acid, 160g of cellulose acetate, 15g of adsorbent ZrO2@CMSA-PEI-DA, and 7g of ethylene diethyl ester were mixed evenly and added to a twin-screw extruder. The temperatures of zones 1 to 5 of the twin-screw extruder were 135°C, 165°C, 185°C, 205°C, and 225°C, respectively; the screw speed was 60r / min; the feeding speed was 8.5r / min; the receiving distance was 15cm, and ultrafine fibers were obtained through a melt-blowing process, and then a fiber membrane, i.e., an air filter material, was obtained after flat pressing.

[0112] Example 3

[0113] (1) Synthesis of adsorbent:

[0114] 1.5 g of salicylaldehyde was dissolved in 20 mL of deionized water, 90 mL of ethanol was added, and the mixture was ultrasonicated for 30 minutes. 30 mL of glycerol was then added and ultrasonicated for another 10 minutes. 3 g of trioxymethylene was added to the solution and stirred continuously for 30 minutes. Then, 20 mL of 30% hydrochloric acid was added and stirred continuously for 40 minutes. After the reaction was complete, the resulting solid product was filtered and dried in a 40°C oven for 5 hours to obtain chloromethyl salicylaldehyde (CMSA).

[0115] 3 g of CMSA was added to 30 mL of anhydrous 1,4-dioxane, and then 40 mL of 5% acetic acid aqueous solution was added and ultrasonicated for 20 min. Then 5 g of polyethyleneimine (PEI) and 2 g of ZrO2 were added and stirred continuously for 2 h. After the reaction was completed, the supernatant was removed and the solid at the bottom was washed with 20 mL of anhydrous ethanol for 30 s. The obtained product was dried in an oven at 40 ° C for 5 h to obtain ZrO2@CMSA-PEI, the intermediate product.

[0116] 3g of the above ZrO2@CMSA-PEI was added to a binary solvent consisting of 20mL of dioxane and 20mL of butanol. Under constant stirring for 60min, 2g of dopamine hydrochloride and 1g of the catalyst benzothiazole disulfide were added in sequence. After the reaction, the supernatant was removed and the resulting product was washed with 20mL of anhydrous ethanol for 30s. After washing, it was placed in a 40°C oven and dried for 5h to obtain the adsorbent ZrO2@CMSA-PEI-DA. Its structural diagram is shown in Figure 2 As shown,

[0117] (2) Preparation of air filter materials:

[0118] 240g of polylactic acid, 170g of cellulose acetate, 20g of adsorbent ZrO2@CMSA-PEI-DA, and 10g of ethylene diethyl ester were mixed evenly and added to a twin-screw extruder. The temperatures of zones 1 to 5 of the twin-screw extruder were 140°C, 170°C, 190°C, 210°C, and 230°C, respectively; the screw speed was 70r / min; the feeding speed was 9r / min; the receiving distance was 25cm, and ultrafine fibers were obtained by melt-blowing process, and then fiber membranes, i.e., air filter materials, were obtained after flat pressing. The structural diagram is shown in FIG. Figure 3 As shown in the figure, the photo of the fiber membrane of the air filter material is as follows Figure 4 shown.

[0119] Comparative Example 1

[0120] The difference from Example 3 is that no adsorbent ZrO2@CMSA-PEI-DA was added during the melt-blowing process. The specific preparation steps of the air filter material of this comparative example are as follows:

[0121] Specifically, 240g of polylactic acid, 170g of cellulose acetate, and 10g of ethylene diethyl ester were mixed evenly and added to a twin-screw extruder. The temperatures of zones 1 to 5 of the twin-screw extruder were 140°C, 170°C, 190°C, 210°C, and 230°C, respectively; the screw speed was 70r / min; the feeding speed was 9r / min; the receiving distance was 25cm, and the air filter material was obtained through a melt-blowing process.

[0122] Comparative Example 2

[0123] The difference from Example 3 is that no polyethyleneimine is added. The specific preparation steps of the air filter material of this comparative example are as follows:

[0124] (1) Synthesis of adsorbent:

[0125] 1.5 g of salicylaldehyde was dissolved in 20 mL of deionized water, 90 mL of ethanol was added, and the mixture was ultrasonicated for 30 minutes. 30 mL of glycerol was then added and ultrasonicated for another 10 minutes. 3 g of trioxymethylene was added to the solution and stirred continuously for 30 minutes. Then, 20 mL of 30% hydrochloric acid was added and stirred continuously for 40 minutes. After the reaction was complete, the resulting solid product was filtered and dried in a 40°C oven for 5 hours to obtain chloromethyl salicylaldehyde (CMSA).

[0126] 3 g of CMSA was added to 30 mL of anhydrous 1,4-dioxane, and then 40 mL of 5% acetic acid aqueous solution was added and ultrasonicated for 20 min. Then 2 g of ZrO2 was added and stirred continuously for 2 h. After the reaction was completed, the supernatant was removed and the solid at the bottom was washed with 20 mL of anhydrous ethanol for 30 s. The obtained product was dried in an oven at 40 °C for 5 h to obtain ZrO2@CMSA.

[0127] 3g of the above-mentioned ZrO2@CMSA was added to a binary solvent consisting of 20mL of dioxane and 20mL of butanol. Under constant stirring for 60 minutes, 2g of dopamine hydrochloride and 1g of the catalyst benzothiazole disulfide were added sequentially. After the reaction, the supernatant was removed, and the resulting product was washed with 20mL of anhydrous ethanol for 30 seconds. After washing, it was dried in a 40°C oven for 5 hours to obtain the adsorbent ZrO2@CMSA-DA.

[0128] (2) Preparation of air filter material: 240 g of polylactic acid, 170 g of cellulose acetate, 20 g of adsorbent ZrO2@CMSA-DA, and 10 g of ethylene diethyl ester were mixed evenly and added to a twin-screw extruder. The temperatures of zones 1 to 5 of the twin-screw extruder used were 140°C, 170°C, 190°C, 210°C, and 230°C, respectively; the screw speed was 70 r / min; the feeding speed was 9 r / min; the receiving distance was 25 cm, and the air filter material was obtained by melt-blowing and pressing processes.

[0129] Comparative Example 3

[0130] The difference from Example 3 is that chloromethyl salicylaldehyde is not added. The specific preparation steps of the air filter material of this comparative example are as follows:

[0131] (1) Synthesis of adsorbent:

[0132] 5 g of polyethyleneimine (PEI) and 2 g of ZrO2 were added to 30 mL of anhydrous 1,4-dioxane, and then 40 mL of 5% acetic acid aqueous solution was added and ultrasonicated for 20 minutes. The mixture was stirred continuously for 2 hours. After the reaction was completed, the supernatant was removed and the solid at the bottom was washed with 20 mL of anhydrous ethanol for 30 seconds. The product was dried in an oven at 40°C for 5 hours to obtain ZrO2@PEI.

[0133] 3g of the above-mentioned ZrO2@PEI was added to a binary solvent consisting of 20mL of dioxane and 20mL of butanol. Under constant stirring for 60 minutes, 2g of dopamine hydrochloride and 1g of the catalyst benzothiazole disulfide were added sequentially. After the reaction, the supernatant was removed, and the resulting product was washed with 20mL of anhydrous ethanol for 30 seconds. After washing, it was dried in a 40°C oven for 5 hours to obtain the adsorbent ZrO2@PEI-DA.

[0134] (2) Preparation of air filter materials:

[0135] 240g of polylactic acid, 170g of cellulose acetate, 20g of adsorbent ZrO2@PEI-DA, and 10g of ethylene diethyl ester were mixed evenly and added to a twin-screw extruder. The temperatures of zones 1 to 5 of the twin-screw extruder were 140°C, 170°C, 190°C, 210°C, and 230°C, respectively; the screw speed was 70r / min; the feeding speed was 9r / min; the receiving distance was 25cm, and the air filter material was obtained through melt-blowing and pressing processes.

[0136] Comparative Example 4

[0137] The difference from Example 3 is that dopamine hydrochloride is not added. The specific preparation steps of the air filter material of this comparative example are as follows:

[0138] (1) Synthesis of adsorbent:

[0139] 1.5 g of salicylaldehyde was dissolved in 20 mL of deionized water, 90 mL of ethanol was added, and the mixture was ultrasonicated for 30 minutes. 30 mL of glycerol was then added and ultrasonicated for another 10 minutes. 3 g of trioxymethylene was added to the solution and stirred continuously for 30 minutes. Then, 20 mL of 30% hydrochloric acid was added and stirred continuously for 40 minutes. After the reaction was complete, the resulting solid product was filtered and dried in a 40°C oven for 5 hours to obtain chloromethyl salicylaldehyde (CMSA).

[0140] 3 g of CMSA was added to 30 mL of anhydrous 1,4-dioxane, and then 40 mL of 5% acetic acid aqueous solution was added and ultrasonicated for 20 min. Then 5 g of polyethyleneimine (PEI) and 2 g of ZrO2 were added and stirred continuously for 2 h. After the reaction was completed, the supernatant was removed and the solid at the bottom was washed with 20 mL of anhydrous ethanol for 30 s. The obtained product was dried in an oven at 40 ° C for 5 h to obtain the adsorbent ZrO2@CMSA-PEI.

[0141] (2) Preparation of air filter materials:

[0142] 240g of polylactic acid, 170g of cellulose acetate, 20g of adsorbent ZrO2@CMSA-PEI, and 10g of ethylene diethyl ester were mixed evenly and added to a twin-screw extruder. The temperatures of zones 1 to 5 of the twin-screw extruder were 140°C, 170°C, 190°C, 210°C, and 230°C, respectively; the screw speed was 70r / min; the feeding speed was 9r / min; the receiving distance was 25cm, and the air filter material was obtained through melt-blowing and pressing processes.

[0143] Comparative Example 5

[0144] The difference from Example 3 is that ZrO2 is not added. The specific preparation steps of the air filter material of this comparative example are as follows:

[0145] (1) Synthesis of adsorbent:

[0146] 1.5 g of salicylaldehyde was dissolved in 20 mL of deionized water, 90 mL of ethanol was added, and the mixture was ultrasonicated for 30 minutes. 30 mL of glycerol was then added and ultrasonicated for another 10 minutes. 3 g of trioxymethylene was added to the solution and stirred continuously for 30 minutes. Then, 20 mL of 30% hydrochloric acid was added and stirred continuously for 40 minutes. After the reaction was complete, the resulting solid product was filtered and dried in a 40°C oven for 5 hours to obtain chloromethyl salicylaldehyde (CMSA).

[0147] 3 g of CMSA was added to 30 mL of anhydrous 1,4-dioxane, and then 40 mL of 5% acetic acid aqueous solution was added and ultrasonicated for 20 min. Then 5 g of polyethyleneimine (PEI) was added and stirred continuously for 2 h. After the reaction was completed, the supernatant was removed and the solid at the bottom was washed with 20 mL of anhydrous ethanol for 30 s. The obtained product was dried in an oven at 40 ° C for 5 h to obtain ZrO2@CMSA-PEI.

[0148] 3g of the above-mentioned ZrO2@CMSA-PEI was added to a binary solvent consisting of 20mL of dioxane and 20mL of butanol. Under constant stirring for 60 minutes, 2g of dopamine hydrochloride and 1g of the catalyst benzothiazole disulfide were added sequentially. After the reaction, the supernatant was removed, and the resulting product was washed with 20mL of anhydrous ethanol for 30 seconds. After washing, it was dried in a 40°C oven for 5 hours to obtain the adsorbent ZrO2@CMSA-PEI-DA.

[0149] (2) Preparation of air filter materials:

[0150] 240g of polylactic acid, 170g of cellulose acetate, 20g of adsorbent ZrO2@CMSA-PEI-DA, and 10g of ethylene diethyl ester were mixed evenly and added to a twin-screw extruder. The temperatures of zones 1 to 5 of the twin-screw extruder were 140°C, 170°C, 190°C, 210°C, and 230°C, respectively; the screw speed was 70r / min; the feeding speed was 9r / min; the receiving distance was 25cm, and the air filter material was obtained through a melt-blown process.

[0151] In order to test the performance of the prepared air filter materials, the air filter materials prepared in each embodiment and each comparative example were subjected to adsorption performance and mechanical property tests. Among them, the adsorption performance test part was carried out using the following adsorption experimental steps: the air filter materials obtained in Examples 1-3 and Comparative Examples 1-5 were respectively hung in the sample cabin as samples, and a certain amount of formaldehyde (ammonia and trimethylamine) solution was placed in the cabin. The cabin door was immediately closed, and the cabin fan was turned on to stir for 1 minute. After the cabin air was mixed with the release source pollutants, the fan was turned off, and air sampling was carried out in the blank cabin. The concentration of pollutants in the cabin air was measured as the initial concentration, which was recorded as C A After being sealed for 24 hours, the concentration of air pollutants in the cabin is measured, which is the concentration value of the cabin during a certain period of time, recorded as C B In addition, the mechanical properties of tensile strength and elongation at break of the air filter materials obtained in Examples 1-3 and Comparative Examples 1-5 were tested. The test results of each air filter material are shown in Table 1:

[0152] Table 1 Test results

[0153]

[0154] The adsorption rate of pollutants by passive purification materials is calculated according to the following formula: y = (C A -C B ) / C A , where y is the adsorption rate, %; C A ―Original pollutant concentration value in the experimental chamber, mg / m 3 ; C B ― Pollutant concentration value after adsorption in the experimental chamber, mg / m 3 .

[0155] As can be seen from Table 1 above, the air filter material prepared in this embodiment has a high adsorption rate for formaldehyde, and also has a high adsorption rate for ammonia and trimethylamine. At the same time, the tensile strength is greater than 5.1 MPa and the elongation at break is greater than 40%. This shows that the air filter material prepared in this embodiment has excellent ability to adsorb pollutants in the air and also has good mechanical properties.

[0156] In addition, by comparing Example 3 and Comparative Examples 1-5, it can be seen that the various components of the air filter material prepared in this embodiment all have an effect on the adsorption performance of formaldehyde, ammonia and trimethylamine. That is to say, the various components of the air filter material prepared in this embodiment have a synergistic effect on the adsorption performance of formaldehyde, ammonia and trimethylamine.

[0157] The above description fully discloses the specific embodiments of the present invention. It should be noted that any modifications made by those skilled in the art to the specific embodiments of the present invention do not depart from the scope of the claims. Accordingly, the scope of the claims of the present invention is not limited solely to the foregoing specific embodiments.

Claims

1. A method for preparing an air filter material, characterized in that: The following steps are involved: placing chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide in a first mixed solution and continuously stirring the solution; filtering the product after the reaction and washing and drying the product to obtain an intermediate product having a core-shell structure; The intermediate product is added to a second mixed solvent, and dopamine hydrochloride and a catalyst are added in sequence under continuous stirring. After the reaction, the product is filtered, washed, and dried to obtain an adsorbent; The adsorbent, polymer and additive are subjected to a melt-blowing process and a flat-pressing process to prepare an air filter material.

2. The method according to claim 1, characterized in that The mass ratio of chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide is (2-3):(4-5):(1-2); and / or, The mass ratio of the intermediate product, dopamine hydrochloride and catalyst is (2-3):(1-2):(0.5-1); and / or, The mass ratio of the adsorbent, the polymer and the additive is (10-20):(350-410):(5-10).

3. The method according to claim 1 or 2, characterized in that The first mixed solution includes anhydrous 1,4-dioxane and a 5% acetic acid aqueous solution; the process of placing chloromethyl salicylaldehyde, polyethyleneimine and zirconium dioxide in the first mixed solution and continuously stirring is specifically as follows: Add chloromethyl salicylaldehyde to anhydrous 1,4-dioxane, then add 5% acetic acid aqueous solution for ultrasonication, then add polyethyleneimine and zirconium dioxide and stir continuously until the reaction is complete; The process of placing the mixture in the first mixed solution and continuously stirring the mixture satisfies at least one of the following conditions: The volume ratio of anhydrous 1,4-dioxane and acetic acid aqueous solution is (2-3):(3-4); The mass volume ratio of the chloromethyl salicylaldehyde and anhydrous 1,4-dioxane is (2-3) g: (20-30) mL; The time for adding 5% acetic acid aqueous solution and performing ultrasound is 10 minutes to 60 minutes; The time for adding polyethyleneimine and zirconium dioxide and continuously stirring is 1 hour to 3 hours.

4. The method according to claim 1, wherein The preparation method of the air filter material meets at least one of the following conditions: The second mixed solvent is any one of dioxane and butanol, dioxane and glacial acetic acid, dichloromethane and ethyl acetate; The catalyst is any one of trifluoroacetic acid, benzothiazole disulfide or tetraethyl silicate; The additive is any one of ethylene diethyl ether, di-sec-butylamine, and cyclopropaneamide; The continuous stirring time in the second mixed solvent is 30 min to 80 min.

5. The method according to claim 1, wherein The polymer is a blend of polylactic acid and cellulose acetate; In the melt-blowing process, the mass ratio of polylactic acid to cellulose acetate is (20-24):(15-17).

6. The method according to claim 1, characterized in that The preparation of the air filter material by melt-blowing and flat-pressing the adsorbent, polymer and additive comprises: The polymer, adsorbent and additives are added to the twin-screw extruder. After heating, melting and extrusion, the melt is extruded from the spinneret holes to form ultra-fine filament fibers, which are condensed on the drum-type fiber receiver to form a melt-blown fiber web. The collected meltblown fiber web is pressed flatly and then consolidated into a film to obtain an air filter material.

7. The method according to claim 6, characterized in that The temperatures of zones 1 to 5 of the twin-screw extruder used are 130°C to 140°C, 160°C to 170°C, 180°C to 190°C, 200°C to 210°C, and 220°C to 230°C, respectively; the screw speed is 50r / min to 70r / min; the feeding speed is 8r / min to 9r / min; and the receiving distance is 5cm to 25cm. And / or, the obtained meltblown fiber web has an average diameter of 2 μm to 7 μm and an average pore size of 25 μm to 35 μm.

8. The method according to claim 1, characterized in that Before the step of preparing the intermediate product having a core-shell structure, the method further comprises: Dissolve salicylaldehyde in deionized water, add ethanol and sonicate, then add glycerol and continue sonicating to mix evenly to obtain a salicylaldehyde solution; Adding trioxymethylene to the salicylaldehyde solution and stirring continuously, then adding 30% hydrochloric acid and stirring continuously until the reaction is completed, filtering to obtain a solid product, and drying to obtain chloromethyl salicylaldehyde; The process of preparing the intermediate product having a core-shell structure satisfies at least one of the following conditions: The mass ratio of salicylaldehyde to trioxymethylene is (0.5-1.5):(2-3); The volume ratio of the deionized water, ethanol, glycerol and hydrochloric acid is (1-2):(8-9):(2-3):(1-2); The mass volume ratio of salicylaldehyde to glycerol is: (0.5-1.5) g: (20-30) mL; The ultrasonic time after adding ethanol is 15min to 1h; The time of adding the salicylaldehyde solution and stirring continuously is 20 minutes to 60 minutes; The time for adding 30% hydrochloric acid and continuously stirring is 30 minutes to 60 minutes.

9. An air filter material, characterized in that: The air filter material is prepared by the method according to any one of claims 1 to 8, and the air filter material is used for adsorbing pollutants in the air.

10. An air purification device, characterized in that: The air purification device comprises the air filter material according to claim 9.

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