Process for the preparation of formaldehyde adsorbents

Abstract

The application discloses a preparation method of a formaldehyde adsorbent, and is characterized in that the method comprises the following steps: ①preparing Ce / Co3O4 microspheres; ②growing the Ce / Co3O4 microspheres and anion powder on sodium hydroxymethyl cellulose in situ, and then grafting an ammonium monomer; and the weight ratio of the Ce / Co3O4 microspheres, the sodium hydroxymethyl cellulose, the anion powder and the ammonium monomer is 1-2:3-4:2-3:10-12. The Ce / Co3O4 microspheres synthesized by the method have the advantages of small particle size, developed surface pore structure, high specific surface area and strong adsorption capacity.

Description

Technical Field

[0001] This invention relates to a method for preparing a formaldehyde adsorption agent, belonging to the field of formaldehyde purification technology. Background Technology

[0002] Formaldehyde is a ubiquitous indoor air pollutant with strong toxicity. Long-term exposure to formaldehyde can lead to abnormal immune function, liver damage, lung damage, and impairment of the central nervous system. It can also denature proteins and has a powerful destructive effect on human cells, potentially causing death in severe cases. Formaldehyde is also a potential cause of birth defects and female infertility.

[0003] With increasing environmental pressure and growing public awareness of environmental protection, people are paying more attention to indoor air quality. Various adsorption materials are used for formaldehyde removal, such as porous carbon materials, organometallic frameworks, calcium carbonate, and metal particles. Among these, porous carbon materials are the most commonly used. Activated carbon fiber, as a novel adsorption material, has a larger specific surface area and more developed micropores compared to powdered and granular activated carbon, resulting in a faster adsorption rate. However, activated carbon fiber has fewer functional groups on its surface. During adsorption, it primarily adsorbs non-polar small molecules, falling under the category of physical adsorption. Its adsorption capacity for polar molecules is poor, exhibiting low adsorption affinity and easy desorption. Therefore, the formaldehyde adsorption performance of activated carbon fiber is not ideal. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a formaldehyde adsorbent with strong adsorption capacity, in view of the above-mentioned technical status.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a method for preparing a formaldehyde adsorbent, characterized by comprising the following steps:

[0006] ①Preparation of Ce / Co3O4 microspheres;

[0007] ② Ce / Co3O4 microspheres and negative ion powder were grown in situ on sodium hydroxymethyl cellulose, and then ammonium monomers were grafted onto them.

[0008] The weight ratio of the aforementioned Ce / Co3O4 microspheres, sodium hydroxymethyl cellulose, negative ion powder, and ammonium monomers is 1-2:3-4:2-3:10-12.

[0009] Preferably, the preparation of Ce / Co3O4 microspheres in step ① includes the following steps:

[0010] Cobalt nitrate hexahydrate was placed in a container with 100-120 ml of distilled water and stirred. Sodium oxalate and ammonia were then added, and stirring continued to yield solution A. Cerium nitrate was placed in a container with distilled water and stirred. Polyvinylpyrrolidone was then added, and stirring continued to yield solution B. Solution B was slowly poured into solution A, and the mixture was then transferred to a reaction vessel for hydrothermal treatment. The resulting product was centrifuged, rinsed, and then dried in an oven. The dried product was then calcined in a high-temperature muffle furnace to obtain Ce / Co3O4 microspheres.

[0011] The weight ratio of the aforementioned cobalt nitrate hexahydrate, sodium oxalate, cerium nitrate, and polyvinylpyrrolidone is 2-3:0.4-0.6:1-2:10-14; the aforementioned sodium oxalate and ammonia are mixed in the following ratio: 0.4-0.6g of sodium oxalate with 3-5ml of ammonia, the ammonia concentration being 4-6mol / L.

[0012] Preferably, the hydrothermal temperature is 70–80°C, and the hydrothermal time is 50–60 minutes.

[0013] Preferably, the drying temperature is 60–80°C and the drying time is 4–6 hours.

[0014] Preferably, the calcination temperature is 1000–1200℃ and the calcination time is 1–2 hours.

[0015] Preferably, the rinsing is performed using at least one of anhydrous ethanol, anhydrous methanol, or anhydrous tert-butanol.

[0016] Preferably, the Ce / Co3O4 microspheres have a thickness of 300–400 μm, a particle size range of 50–100 μm, and a pore size of 2.5–3.5 μm.

[0017] Preferably, step ② includes the following steps:

[0018] Ammonium monomers are added to a container containing solvent, then formaldehyde solution is added, the pH of the solution is adjusted to 8-9, the temperature is raised to 40-50℃, and the reaction is carried out for 40-50 minutes until the solution becomes clear and transparent; then sodium carboxymethyl cellulose, Ce / Co3O4 and 2-3g of negative ion powder are added, and then an initiator is added. After mixing evenly, the mixture is reacted at 70-80℃ for 2-3 hours, filtered, the obtained product is washed, and dried to obtain the formaldehyde adsorbent;

[0019] The aforementioned weight ratio of ammonium monomers to initiators is 10–12:0.5–0.7.

[0020] Preferably, the pH of the solution is adjusted using a sodium carbonate solution with a weight percentage of 10%.

[0021] Preferably, the ammonium monomer is at least one of ammonium carbonate, ammonium sulfate, or ammonium bromide.

[0022] Preferably, the initiator is at least one of lauroyl peroxide, tert-butyl hydroperoxide, or dicumyl peroxide.

[0023] Preferably, the rinsing is performed using at least one of anhydrous ethanol, anhydrous methanol, or anhydrous tert-butanol.

[0024] Compared with existing technologies, the advantages of this invention are: physical adsorption methods for removing formaldehyde have low activated carbon utilization and poor effect, and are prone to causing secondary pollution. The Ce / Co3O4 microspheres synthesized in this invention have the advantages of small particle size, well-developed surface pore structure and high specific surface area, and strong adsorption capacity.

[0025] Using sodium carboxymethyl cellulose as the functional monomer, it first reacts with Ce / Co3O4 microspheres and negative ion powder, increasing the specific surface area of ​​the adsorbent material. This not only adsorbs organic molecules such as formaldehyde but also decomposes the adsorbed organic molecules into smaller molecules, releasing beneficial negative ions. The negative ion powder transfers negative charges to dust, smoke, and other particles in the air, causing them to settle and purify the air. Simultaneously, the grafted ammonium monomers give the adsorbent material resistance to hydrolysis and swelling, making it suitable for manufacturing durable, long-lasting filter materials. Furthermore, it also has a certain adsorption capacity for formaldehyde.

[0026] The preparation method of this invention is simple, mild, and easy to control. All raw materials used are non-toxic or low-toxic, resulting in low raw material consumption and low cost. Furthermore, no toxic byproducts are generated, making it an environmentally friendly synthesis method. The resulting adsorbent material has a high content of functional groups and maintains good morphology and strength, showing broad application prospects in functional textiles, water and air purification, and the separation and extraction of chemical substances. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the embodiments.

[0028] Example 1, (1) Weigh 2g of cobalt nitrate hexahydrate and place it in a container containing 100ml of distilled water, and stir for 30min. Then add 0.4g of sodium oxalate and 3ml of ammonia water, and continue stirring for 10min to obtain solution A. Weigh 1g of cerium nitrate and place it in a container containing 100ml of distilled water, and stir for 30min. Then add 10g of polyvinylpyrrolidone, and stir for 20min to obtain solution B. Slowly pour solution B into solution A, and then transfer the mixed solution to a stainless steel reactor lined with polytetrafluoroethylene. Perform hydrothermal reaction at 70℃ for 50min. Centrifuge the obtained product, wash it three times with anhydrous ethanol, and then put the solid into an oven to dry at 70℃ for 4h. Place the obtained dried sample into a high-temperature muffle furnace at 1000℃ and calcine for 1h to obtain Ce / Co3O4.

[0029] (2) Add 10g of ammonium carbonate to a container containing 50ml of isopropanol, then add 3ml of formaldehyde solution, adjust the pH of the solution to 8 with 10% sodium carbonate solution, heat to 40℃ and react for 40min to make the solution clear and transparent. Then add 3g of sodium carboxymethyl cellulose, 1g of Ce / Co3O4 and 2g of negative ion powder, and 0.5g of lauroyl peroxide. After mixing evenly, react at 70℃ for 2h, filter, wash the obtained solid three times with anhydrous ethanol, and dry to obtain a composite material that can adsorb formaldehyde.

[0030] Example 2, (1) Weigh 2.5g of cobalt nitrate hexahydrate and place it in a container containing 110ml of distilled water, and stir for 35min. Then add 0.5g of sodium oxalate and 4ml of ammonia water, and continue stirring for 15min to obtain solution A. Weigh 1.5g of cerium nitrate and place it in a container containing 110ml of distilled water, and stir for 35min. Then add 12g of polyvinylpyrrolidone, and stir for 25min to obtain solution B. Slowly pour solution B into solution A, and then transfer the mixed solution to a stainless steel reactor lined with polytetrafluoroethylene. Perform hydrothermal reaction at 75℃ for 55min. Centrifuge the obtained product, wash it three times with anhydrous ethanol, and then put the solid into an oven to dry at 70℃ for 5h. Place the obtained dried sample into a high-temperature muffle furnace at 1100℃ and calcine for 1.5h to obtain Ce / Co3O4.

[0031] (2) Add 11g of ammonium carbonate to a container containing 55ml of isopropanol, then add 4ml of formaldehyde solution, adjust the pH of the solution to 8.5 with 10% sodium carbonate solution, heat to 45℃ and react for 45min to make the solution clear and transparent. Then add 3.5g of sodium carboxymethyl cellulose, 1.5g of Ce / Co3O4 and 2.5g of negative ion powder, and 0.6g of lauroyl peroxide. After mixing evenly, react at 75℃ for 2.5h, filter, wash the obtained solid three times with anhydrous ethanol, and dry to obtain a composite material that can adsorb formaldehyde.

[0032] Example 3, (1) Weigh 3g of cobalt nitrate hexahydrate and place it in a container containing 120ml of distilled water, and stir for 40min. Then add 0.6g of sodium oxalate and 5ml of ammonia water, and continue stirring for 20min to obtain solution A. Weigh 2g of cerium nitrate and place it in a container containing 120ml of distilled water, and stir for 40min. Then add 14g of polyvinylpyrrolidone, and stir for 30min to obtain solution B. Slowly pour solution B into solution A, and then transfer the mixed solution to a stainless steel reactor lined with polytetrafluoroethylene. Perform hydrothermal reaction at 80℃ for 60min. Centrifuge the obtained product, wash it three times with anhydrous ethanol, and then put the solid into an oven to dry at 70℃ for 6h. Place the dried sample into a high-temperature muffle furnace at 1200℃ and calcine for 2h to obtain Ce / Co3O4.

[0033] (2) Add 12g of ammonium carbonate to a container containing 60ml of isopropanol, then add 5ml of formaldehyde solution, adjust the pH of the solution to 9 with 10% sodium carbonate solution, heat to 50℃ and react for 50min to make the solution clear and transparent. Then add 4g of sodium carboxymethyl cellulose, 2g of Ce / Co3O4 and 3g of negative ion powder, and 0.7g of lauroyl peroxide. After mixing evenly, react at 80℃ for 3h, filter, wash the obtained solid three times with anhydrous ethanol, and dry to obtain a composite material that can adsorb formaldehyde.

[0034] Comparative Example 1: Ce / Co3O4 was not synthesized.

[0035] (1) Add 12g of ammonium carbonate to a container containing 60ml of isopropanol, then add 5ml of formaldehyde solution, adjust the pH of the solution to 9 with 10% sodium carbonate solution, heat to 50℃ and react for 50min until the solution becomes clear and transparent. Then add 4g of sodium carboxymethyl cellulose and 3g of negative ion powder, and add 0.7g of lauroyl peroxide. Mix well and react at 80℃ for 3h. Filter, wash the obtained solid three times with anhydrous ethanol, and dry to obtain a composite material that can adsorb formaldehyde.

[0036] Comparative Example 2: No negative ion powder was introduced.

[0037] (1) Weigh 3g of cobalt nitrate hexahydrate and place it in a container containing 120ml of distilled water, and stir for 40min. Then add 0.6g of sodium oxalate and 5ml of ammonia water, and continue stirring for 20min to obtain solution A. Weigh 2g of cerium nitrate and place it in a container containing 120ml of distilled water, and stir for 40min. Then add 14g of polyvinylpyrrolidone, and stir for 30min to obtain solution B. Slowly pour solution B into solution A, and then transfer the mixed solution to a stainless steel reactor lined with polytetrafluoroethylene. Perform a hydrothermal reaction at 80℃ for 60min. Centrifuge the obtained product, wash it three times with anhydrous ethanol, and then place the solid in an oven to dry at 70℃ for 6h. Place the dried sample in a high-temperature muffle furnace at 1200℃ and calcine for 2h to obtain Ce / Co3O4.

[0038] (2) Add 12g of ammonium carbonate to a container containing 60ml of isopropanol, then add 5ml of formaldehyde solution, adjust the pH of the solution to 9 with 10% sodium carbonate solution, heat to 50℃ and react for 50min until the solution becomes clear and transparent. Then add 4g of sodium carboxymethyl cellulose and 2g of Ce / Co3O4, and then add 0.7g of lauroyl peroxide. After mixing evenly, react at 80℃ for 3h, filter, wash the obtained solid three times with anhydrous ethanol, and dry to obtain a composite material that can adsorb formaldehyde.

[0039] Comparative Example 3, without introducing ammonium monomers.

[0040] (1) Weigh 3g of cobalt nitrate hexahydrate and place it in a container containing 120ml of distilled water, and stir for 40min. Then add 0.6g of sodium oxalate and 5ml of ammonia water, and continue stirring for 20min to obtain solution A. Weigh 2g of cerium nitrate and place it in a container containing 120ml of distilled water, and stir for 40min. Then add 14g of polyvinylpyrrolidone, and stir for 30min to obtain solution B. Slowly pour solution B into solution A, and then transfer the mixed solution to a stainless steel reactor lined with polytetrafluoroethylene. Perform a hydrothermal reaction at 80℃ for 60min. Centrifuge the obtained product, wash it three times with anhydrous ethanol, and then place the solid in an oven to dry at 70℃ for 6h. Place the dried sample in a high-temperature muffle furnace at 1200℃ and calcine for 2h to obtain Ce / Co3O4.

[0041] (2) In a container containing 60 ml of isopropanol, 5 ml of formaldehyde solution was added. The pH of the solution was adjusted to 9 with 10% sodium carbonate solution. The temperature was raised to 50°C and reacted for 50 min until the solution became clear and transparent. Then, 4 g of sodium carboxymethyl cellulose, 2 g of Ce / Co3O4, and 3 g of negative ion powder were added. 0.7 g of lauroyl peroxide was added, and the mixture was stirred evenly. The mixture was then reacted at 80°C for 3 h. After filtration, the obtained solid was washed three times with anhydrous ethanol and dried to obtain a composite material that can adsorb formaldehyde.

[0042] The samples obtained in Examples 1-3 and Comparative Examples 1-3 were suspended in sample chambers, respectively. A certain amount of formaldehyde solution was added to the chambers, the chamber doors were immediately closed, and the chamber fan was turned on to stir for 1 minute. After the air inside the chamber was mixed with the pollutants from the release source, the fan was turned off, and air samples were taken from the blank chamber. The concentration of pollutants in the air inside the chamber was measured as the initial concentration, denoted as C. A After being sealed for 24 hours, the concentration of air pollutants inside the chamber is measured. This concentration value within the chamber over a certain period is denoted as C. B .

[0043] The pollutant removal rate of passive purification materials is calculated using the following formula:

[0044]

[0045] y—Removal rate, %

[0046] C A —Original pollutant concentration in the experimental chamber, mg / m³ 3

[0047] C B —Concentration of pollutants after adsorption in the experimental chamber, mg / m³ 3

[0048] The results of adsorption experiments on the adsorbent materials prepared in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1:

[0049]

[0050] As can be seen from the table above, the materials obtained in each embodiment have excellent formaldehyde adsorption effect, with an adsorption rate of over 99%.

[0051] The present invention has been described above by way of example. It is obvious that the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution, or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention. The protection scope of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for producing a formaldehyde adsorbent, characterized by Includes the following steps: Preparation of Ce / Co3O4 microspheres; Ammonium monomers are added to a container containing solvent, then formaldehyde solution is added, the pH of the solution is adjusted to 8-9, the temperature is raised to 40-50℃, and the reaction is carried out until the solution becomes clear and transparent; then sodium carboxymethyl cellulose, Ce / Co3O4 and negative ion powder are added, and then an initiator is added, mixed evenly, and reacted at 70-80℃, filtered, the obtained product is washed, dried, and the formaldehyde adsorbent is obtained; The weight ratio of the aforementioned Ce / Co3O4 microspheres, sodium hydroxymethyl cellulose, negative ion powder, and ammonium monomers is 1~2:3~4:2~3:10~12.

2. The method for preparing the formaldehyde adsorbent according to claim 1, characterized in that... step The preparation of the Ce / Co3O4 microspheres described herein includes the following steps: Cobalt nitrate hexahydrate was placed in a container with 100-120 ml of distilled water and stirred. Sodium oxalate and ammonia were then added, and stirring continued to obtain solution A. Cerium nitrate was placed in a container with distilled water and stirred. Polyvinylpyrrolidone was then added, and stirring continued to obtain solution B. Solution B was slowly poured into solution A, and the mixture was then transferred to a reaction vessel for hydrothermal treatment. The resulting product was centrifuged, rinsed, and then dried in an oven. The dried product was then calcined in a high-temperature muffle furnace to obtain Ce / Co3O4 microspheres. The weight ratio of the aforementioned cobalt nitrate hexahydrate, sodium oxalate, cerium nitrate, and polyvinylpyrrolidone is 2~3: 0.4~0.6: 1~2: 10~14; the aforementioned sodium oxalate and ammonia are mixed in the following ratio: 0.4~0.6g of sodium oxalate with 3~5ml of ammonia, and the ammonia concentration is 4~6mol / L.

3. The method for preparing the formaldehyde adsorbent according to claim 2, characterized in that... The hydrothermal temperature is 70~80℃; the hydrothermal time is 50~60min.

4. The method for preparing the formaldehyde adsorbent according to claim 2, characterized in that... The drying temperature is 60~80℃, and the drying time is 4~6 hours.

5. The method for preparing the formaldehyde adsorbent according to claim 2, characterized in that... The calcination temperature is 1000~1200℃, and the calcination time is 1~2h.

6. The method for preparing the formaldehyde adsorbent according to claim 2, characterized in that... The rinsing process uses at least one of anhydrous ethanol, anhydrous methanol, or anhydrous tert-butanol.

7. The method for preparing the formaldehyde adsorbent according to claim 2, characterized in that... The Ce / Co3O4 microspheres have a thickness of 300~400μm, a particle size range of 50~100μm, and a pore size of 2.5~3.5μm.

8. The method for preparing the formaldehyde adsorbent according to claim 1, characterized in that... step The weight ratio of ammonium monomers to initiators described herein is 10~12: 0.5~0.

7.

9. The method for preparing the formaldehyde adsorbent according to claim 1, characterized in that... The pH of the solution was adjusted using a 10% sodium carbonate solution by weight.

10. The method for preparing the formaldehyde adsorbent according to claim 1, characterized in that... The ammonium monomer is at least one of ammonium carbonate, ammonium sulfate, or ammonium bromide.

11. The method for preparing the formaldehyde adsorbent according to claim 1, characterized in that... The initiator is at least one of lauroyl peroxide, tert-butyl hydroperoxide, or dicumyl peroxide.

12. The method for preparing the formaldehyde adsorbent according to claim 1, characterized in that... The rinsing process uses at least one of anhydrous ethanol, anhydrous methanol, or anhydrous tert-butanol.

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