Method for combined adsorption purification of formaldehyde and carbon dioxide

Abstract

The application discloses a formaldehyde and carbon dioxide combined adsorption purification method, characterized in that a porous adsorption material with aluminum atom sites on the surface to form an active electron gathering area is adopted, after capturing formaldehyde and carbon dioxide molecules by utilizing the porous characteristics, the aluminum atom sites of the active electron gathering area and the carbon dioxide are reacted to generate a quasi-carbonate structure, and the carbon dioxide is deformed into a V-shaped polar structure; then the deformed carbon dioxide and hydrogen atoms of formaldehyde are combined to form a polar hydrogen bond, so that the intermolecular strong force is obtained to tightly combine the formaldehyde molecules and the carbon dioxide molecules, and the combined adsorption removal of the carbon dioxide and the formaldehyde is realized. The application can simultaneously adsorb the two harmful gases of formaldehyde and carbon dioxide, has the characteristics of high adsorption efficiency and high adsorption strength, and is especially suitable for being used in newly decorated rooms, and improves the indoor air purification effect.

Description

Technical Field

[0001] This invention relates to the field of waste gas treatment technology, and in particular to a method for the combined adsorption and purification of formaldehyde and carbon dioxide. Background Technology

[0002] Formaldehyde, especially in newly renovated homes, is a significant pollutant affecting human health. Some furniture and building materials can even release formaldehyde over a long period. Inhaling formaldehyde can damage the respiratory system, necessitating passive adsorption purification strategies. Additionally, high levels of carbon dioxide in respiration can also negatively impact health, as inhaling carbon dioxide can impair sensory perception. Some air purifiers have incorporated carbon dioxide adsorption capabilities. Therefore, both formaldehyde and carbon dioxide are harmful gases that require long-term purification.

[0003] However, existing adsorption treatment technologies are all designed based on the removal of a single pollutant. For example, CN117244399A disclosed an environmentally friendly formaldehyde eliminator and its preparation method, CN116459807A disclosed a modified keratin-based formaldehyde adsorbent and its preparation method, CN116531894A disclosed a formaldehyde adsorbent material preparation process, and CN201210500176.4 disclosed a carbon dioxide air purifier, etc.

[0004] Therefore, the existing adsorption treatment technology has the following drawbacks: limited functionality, significant interference during the adsorption process, low adsorption intensity, and easy re-release. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a method for the combined adsorption and purification of formaldehyde and carbon dioxide that can simultaneously adsorb two harmful gases, formaldehyde and carbon dioxide, with high adsorption efficiency and high adsorption intensity.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for the combined adsorption and purification of formaldehyde and carbon dioxide is characterized by employing a porous adsorption material with aluminum atom sites on its surface forming active electron aggregation regions. After capturing formaldehyde and carbon dioxide molecules using its porous properties, the aluminum atom sites in the active electron aggregation regions react with carbon dioxide to form a quasi-carbonate structure, transforming the carbon dioxide into a V-shaped polar structure. Then, the hydrogen atoms of the transformed carbon dioxide and formaldehyde combine to form polarized hydrogen bonds, obtaining strong intermolecular forces to tightly bind formaldehyde and carbon dioxide molecules, thereby achieving the combined adsorption and removal of carbon dioxide and formaldehyde.

[0008] More specifically, the reaction equation for the aluminum atom sites and carbon dioxide in the above process is Al + e. - + CO2→Al 3+ O=C - =O···Al 3+ (Electron transfer and electron cloud overlap), the reaction equation for the hydrogen atom combination of deformed carbon dioxide and formaldehyde is 2HCHO + CO2 → COH2. 2+ O=C - =O··· 2+ H2OC (hydrogen bonding orientation interaction). As seen from the above process, this method captures carbon dioxide and formaldehyde through a porous structure. First, the aluminum sites exert an inductive force on carbon dioxide, adsorbing and fixing it. This causes the carbon dioxide electron cloud to deform and form polar centers. Then, the initial inductive force between formaldehyde and carbon dioxide transforms into an orientation force, further generating a secondary inductive force, greatly enhancing the attraction between formaldehyde and carbon dioxide. Therefore, this method can not only simultaneously adsorb and purify carbon dioxide and formaldehyde, but also features good adsorption efficiency and strong adsorption capacity.

[0009] Furthermore, this method relies on a formaldehyde-carbon dioxide co-adsorbent, which is a solid porous material and the effective component is aluminum-doped hexagonal boron nitride.

[0010] The aluminum-doped hexagonal boron nitride is a solid porous material combining aluminum metal and hexagonal boron nitride doping, with hexagonal boron nitride serving as the substrate and aluminum participating in the adsorption reaction. Hexagonal boron nitride, also known as white graphite, possesses excellent heat resistance, corrosion resistance, and chemical stability. Importantly, it exhibits a hexagonal network layered structure similar to graphite. Adsorbents formed using this substrate are not only stable but also possess a porous adsorption structure, enhancing the adsorption treatment effect. In this way, the non-metallic sites on the surface of aluminum-doped hexagonal boron nitride form the main reaction sites, which are mainly responsible for the initial adsorption and capture of formaldehyde and carbon dioxide. Because aluminum doping changes the electron distribution on the surface of hexagonal boron nitride and makes it polarized, the non-metallic sites form a dual capture effect of "van der Waals force + electrostatic attraction" with formaldehyde or carbon dioxide, thereby increasing the adsorption intensity of the two pollutants by more than 10 times. The metallic sites on the surface of aluminum-doped hexagonal boron nitride are highly active electron aggregation regions, which are mainly responsible for the co-adsorption of formaldehyde and carbon dioxide. Carbon dioxide first forms a quasi-carbonate structure with aluminum atomic sites. At this time, carbon dioxide has been transformed into a V-shaped polar structure. Then, the hydrogen atoms of formaldehyde can form stronger polarized hydrogen bonds with carbon dioxide. Formaldehyde molecules and carbon dioxide form strong intermolecular interactions and are thus adsorbed and fixed.

[0011] Furthermore, the formaldehyde-carbon dioxide combined adsorbent comprises the following phase materials in the following mass ratios: 0.01-0.08 parts of aluminum oxide phase, 0.05-0.15 parts of pure hexagonal boron nitride phase, and 0.77-0.94 parts of aluminum-doped hexagonal boron nitride phase.

[0012] The primary phase in this formulation is aluminum-doped hexagonal boron nitride, which is the effective component of the adsorbent. The remaining phases are present in smaller quantities, and their role is to better facilitate the interconnection of the hexagonal network layers of boron nitride to form a porous structure, thus making its physical structure more stable. Simultaneously, the remaining phases are reaction products, which, through the equilibrium effect of the reaction equation, can form a dynamic compensating equilibrium after the effective component is consumed, better ensuring the persistence of the adsorption effect.

[0013] Furthermore, the formaldehyde-carbon dioxide combined adsorbent comprises the following phase materials in the following mass ratios: 0.03 parts of aluminum oxide phase, 0.09 parts of pure hexagonal boron nitride phase, and 0.88 parts of aluminum-doped hexagonal boron nitride phase.

[0014] The above ratio has been verified in practice to achieve the best results.

[0015] Furthermore, the formaldehyde-carbon dioxide combined adsorbent is prepared using the following steps:

[0016] 1. Using a ratio of 500 mL deionized water to 0.2 mol boric acid (H3BO3) powder, heat the deionized water to 40-60℃ (preferably to 50℃) and mix it with the boric acid powder, stirring until homogeneous to form a boric acid solution;

[0017] 2. Add a certain amount of melamine (C3N6H6) to the above boric acid solution and stir until a transparent mixed solution is formed. Gradually heat the mixed solution to 85-95℃ (preferably 90℃), wherein the molar ratio of boric acid to melamine is controlled to be 1:(2-4).

[0018] 3. Add a certain amount of aluminum nitrate to the mixed solution obtained in step 2 and mix well, controlling the molar ratio of boron to aluminum to be 1:(0.01-0.5).

[0019] 4. The mixed solution obtained in step 3 is placed in an air environment at 85-95℃ (preferably 90℃) for evaporation to obtain a white solid agglomerate;

[0020] 5. Place the white solid agglomerate obtained in step 4 into a calcination apparatus (e.g., a muffle furnace) and calcine it at 1100-1300℃ (preferably 1200℃) for 7-9 hours (preferably 8 hours) under an argon (Ar) atmosphere. Before calcination, the rate at which the calcination apparatus is raised from room temperature to the calcination temperature is 10℃ / min, and the heating time is about 120 minutes. The calcination yields brown solid granular material.

[0021] 6. The brown solid particulate material obtained in step 5 is calcined at 1100-1300℃ (preferably 1200℃) for 7-9 hours (preferably 8 hours) in an ammonia (NH3) atmosphere. Before calcination, the calcination device is heated from room temperature to the calcination temperature at a rate of 10℃ / min and the heating time is about 120 minutes. The white porous solid material obtained by calcination is the formaldehyde and carbon dioxide combined adsorbent.

[0022] In the above process, in step 2, boric acid and melamine first form a polymer, and during heating, (C3H6N6)(H3B)3O3 is gradually formed, with the reaction equation being (CH2)6N4 + 3H3BO3 → (C3H6N6)(H3B)3O3 + 3H2O; in step 3, (C3H6N6)(H3B)3O3 forms a complex with aluminum ions, with the reaction equation being Al 3+ + 3(C3H6N6)(H3B)3O3 + 3e - →Al 3+ ...[(C3H6N6)(H3B)3O3]3 3- The above preparation process has the advantages of simple procedure, fast reaction rate, and high product yield. The product generated by the reaction has a porous material structure, which is the above-mentioned adsorbent material whose main component is aluminum-doped hexagonal boron nitride phase.

[0023] In summary, this invention can simultaneously adsorb two harmful gases, formaldehyde and carbon dioxide, and features strong adsorption efficiency and high adsorption intensity, making it particularly suitable for use in newly renovated homes to improve indoor air purification. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the microscopic mechanism of formaldehyde / carbon dioxide co-adsorption on the surface of the adsorbent material in an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram comparing the adsorption effects of the adsorbent material of the present invention and a porous adsorbent material composed of pure hexagonal boron nitride. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to specific embodiments.

[0027] Example: A method for the combined adsorption and purification of formaldehyde and carbon dioxide, characterized by the use of a porous adsorbent material with aluminum atom sites on its surface forming active electron aggregation regions. After capturing formaldehyde and carbon dioxide molecules using its porous properties, the aluminum atom sites in the active electron aggregation regions react with carbon dioxide to form a quasi-carbonate structure, transforming the carbon dioxide into a V-shaped polar structure. Then, the hydrogen atoms of the transformed carbon dioxide and formaldehyde combine to form polarized hydrogen bonds, obtaining strong intermolecular forces to tightly bind formaldehyde and carbon dioxide molecules, thereby achieving the combined adsorption and removal of carbon dioxide and formaldehyde.

[0028] More specifically, the reaction equation for the aluminum atom sites and carbon dioxide in the above process is Al + e. - + CO2→Al 3+ O=C - =O···Al 3+ (Electron transfer and electron cloud overlap), the reaction equation for the hydrogen atom combination of deformed carbon dioxide and formaldehyde is 2HCHO + CO2 → COH2. 2+ O=C - =O··· 2+ H2OC (hydrogen bonding orientation interaction). As seen from the above process, this method captures carbon dioxide and formaldehyde through a porous structure. First, the aluminum sites exert an inductive force on carbon dioxide, adsorbing and fixing it. This causes the carbon dioxide electron cloud to deform and form polar centers. Then, the initial inductive force between formaldehyde and carbon dioxide transforms into an orientation force, further generating a secondary inductive force, greatly enhancing the attraction between formaldehyde and carbon dioxide. Therefore, this method can not only simultaneously adsorb and purify carbon dioxide and formaldehyde, but also features good adsorption efficiency and strong adsorption capacity.

[0029] In practice, this method relies on a formaldehyde-carbon dioxide co-adsorbent, which is a solid porous material and its effective component is aluminum-doped hexagonal boron nitride.

[0030] The aluminum-doped hexagonal boron nitride is a solid porous material combining aluminum metal and hexagonal boron nitride doping, with hexagonal boron nitride serving as the substrate and aluminum participating in the adsorption reaction. Hexagonal boron nitride, also known as white graphite, possesses excellent heat resistance, corrosion resistance, and chemical stability. Importantly, it exhibits a hexagonal network layered structure similar to graphite. Adsorbents formed using this substrate are not only stable but also possess a porous adsorption structure, enhancing the adsorption treatment effect.

[0031] For details on the adsorption principle and process of the above adsorbent, please refer to [link / reference needed]. Figure 1Understanding the process, the non-metallic sites on the surface of aluminum-doped hexagonal boron nitride form the primary reaction sites, mainly responsible for the initial adsorption and capture of formaldehyde and carbon dioxide. Because aluminum doping alters the electron distribution on the hexagonal boron nitride surface, giving it a polar orientation, the non-metallic sites also form a dual capture effect with formaldehyde or carbon dioxide through "van der Waals forces + electrostatic attraction," thus increasing the adsorption intensity of both pollutants by more than 10 times. The metallic sites on the surface of aluminum-doped hexagonal boron nitride are highly active electron-gathering regions, mainly responsible for the co-adsorption of formaldehyde and carbon dioxide. Carbon dioxide first forms a quasi-carbonate structure with aluminum atomic sites, at which point it has transformed into a V-shaped polar structure. Then, the hydrogen atoms of formaldehyde can form stronger polarized hydrogen bonds with carbon dioxide, and formaldehyde molecules and carbon dioxide form strong intermolecular interactions, thus being adsorbed and fixed. Of course, in other embodiments, the adsorbent can also employ other strategies to form a porous structure and use materials that, after aluminum doping, alter the surface electron distribution to form a polar orientation and generate highly active surface metallic sites as the substrate material; these will not be detailed here.

[0032] In practice, the formaldehyde-carbon dioxide combined adsorbent comprises the following phase materials in the following mass ratios: 0.01-0.08 parts of aluminum oxide phase, 0.05-0.15 parts of pure hexagonal boron nitride phase, and 0.77-0.94 parts of aluminum-doped hexagonal boron nitride phase.

[0033] The primary phase in this formulation is aluminum-doped hexagonal boron nitride, which is the effective component of the adsorbent. The remaining phases are present in smaller quantities, and their role is to better facilitate the interconnection of the hexagonal network layers of boron nitride to form a porous structure, thus making its physical structure more stable. Simultaneously, the remaining phases are reaction products, which, through the equilibrium effect of the reaction equation, can form a dynamic compensating equilibrium after the effective component is consumed, better ensuring the persistence of the adsorption effect.

[0034] In practice, as the optimal formulation, the formaldehyde-carbon dioxide combined adsorbent comprises the following phase materials in the following mass ratios: 0.03 parts aluminum oxide phase, 0.09 parts pure hexagonal boron nitride phase, and 0.88 parts aluminum-doped hexagonal boron nitride phase.

[0035] The above ratio has been verified in practice to achieve the best results.

[0036] In practice, the formaldehyde-carbon dioxide combined adsorbent is prepared using the following steps:

[0037] 1. Using a ratio of 500 mL deionized water to 0.2 mol boric acid (H3BO3) powder, heat the deionized water to 40-60℃ (preferably to 50℃) and mix it with the boric acid powder, stirring until homogeneous to form a boric acid solution;

[0038] 2. Add a certain amount of melamine (C3N6H6) to the above boric acid solution and stir until a transparent mixed solution is formed. Gradually heat the mixed solution to 85-95℃ (preferably 90℃), wherein the molar ratio of boric acid to melamine is controlled to be 1:(2-4).

[0039] 3. Add a certain amount of aluminum nitrate to the mixed solution obtained in step 2 and mix well, controlling the molar ratio of boron to aluminum to be 1:(0.01-0.5).

[0040] 4. The mixed solution obtained in step 3 is placed in an air environment at 85-95℃ (preferably 90℃) for evaporation to obtain a white solid agglomerate;

[0041] 5. Place the white solid agglomerate obtained in step 4 into a calcination apparatus (e.g., a muffle furnace) and calcine it at 1100-1300℃ (optimal 1200℃) for 7-9 hours (optimal 8 hours) under an argon (Ar) atmosphere. Before calcination, the rate at which the calcination apparatus is raised from room temperature to the calcination temperature is 10℃ / min, and the heating time is about 120 minutes. Calcination yields brown solid granular material.

[0042] 6. The brown solid particulate material obtained in step 5 is calcined in an ammonia (NH3) atmosphere at 1100-1300℃ (optimal 1200℃) for 7-9 hours (optimal 8 hours). Before calcination, the calcination device is heated from room temperature to the calcination temperature at a rate of 10℃ / min and the heating time is about 120 minutes. The white porous solid material obtained by calcination is the formaldehyde and carbon dioxide combined adsorbent.

[0043] In the above process, in step 2, boric acid and melamine first form a polymer, and during heating, (C3H6N6)(H3B)3O3 is gradually formed, with the reaction equation being (CH2)6N4 + 3H3BO3 → (C3H6N6)(H3B)3O3 + 3H2O; in step 3, (C3H6N6)(H3B)3O3 forms a complex with aluminum ions, with the reaction equation being Al 3+ + 3(C3H6N6)(H3B)3O3 + 3e - →Al 3+ ...[(C3H6N6)(H3B)3O3]3 3- The above preparation process has the advantages of simple procedure, fast reaction rate and high product yield.

[0044] To further verify the effectiveness of this application, the applicant selected the formaldehyde-carbon dioxide co-adsorbent prepared in the above-mentioned preferred embodiment and a conventional porous adsorbent material composed of pure hexagonal boron nitride for comparative experiments. Comparative experiments were conducted under three conditions: adsorption of carbon dioxide alone, adsorption of formaldehyde alone, and co-adsorption of both carbon dioxide and formaldehyde. The experimental structure is as follows: Figure 2 As shown, we can see that: 1. The average carbon dioxide capture rate is significantly improved (<10% → 70%+); 2. The average formaldehyde adsorption rate is significantly improved (~10% → ~80%); 3. The formaldehyde / carbon dioxide co-adsorption rate is significantly improved (<10% → ~70%). Therefore, it can be concluded that this invention can not only simultaneously adsorb carbon dioxide and formaldehyde, but also achieve a significantly improved adsorption effect compared to conventional adsorbent materials.

Claims

1. A method for the combined adsorption and purification of formaldehyde and carbon dioxide, characterized in that, A porous adsorbent material with aluminum atom sites forming active electron aggregation regions on its surface is used to capture formaldehyde and carbon dioxide molecules. The aluminum atom sites in these active electron aggregation regions react with carbon dioxide to form a pseudo-carbonate structure, transforming the carbon dioxide into a V-shaped polar structure. Then, the hydrogen atoms of the transformed carbon dioxide and formaldehyde combine to form polarized hydrogen bonds, resulting in strong intermolecular forces that tightly bind formaldehyde and carbon dioxide molecules, achieving the joint adsorption and removal of carbon dioxide and formaldehyde. The reaction equation between the aluminum atom sites and carbon dioxide is Al + e⁻. - + CO2→ Al 3+ O=C - =O···Al 3+ The reaction equation for the hydrogen atoms of carbon dioxide and formaldehyde after deformation is 2HCHO + CO2 → COH2. 2+ O=C - =O··· 2+ H2OC; The method relies on a formaldehyde-carbon dioxide co-adsorbent, which is a solid porous material and the effective component is aluminum-doped hexagonal boron nitride. The formaldehyde-carbon dioxide combined adsorbent was prepared using the following steps: Step 1. According to the ratio of 500 mL of deionized water to 0.2 mol of boric acid powder, heat the deionized water to 40-60℃ and mix it with boric acid powder and stir evenly to form a boric acid solution; Step 2. Add a certain amount of melamine to the above boric acid solution and stir until a transparent mixed solution is formed. Gradually heat the mixed solution to 85-95℃, while controlling the molar ratio of boric acid to melamine to be 1:(2-4). Step 3. Add a certain amount of aluminum nitrate to the mixed solution obtained in Step 2 and mix well, controlling the molar ratio of boron to aluminum to be 1:(0.01-0.5). Step 4. Place the mixed solution obtained in Step 3 in an air environment at 85-95℃ to evaporate, and obtain a white solid agglomerate; Step 5. Place the white solid agglomerate obtained in Step 4 into a calcination apparatus, raise the calcination apparatus from room temperature to a calcination temperature of 1100-1300℃, wherein the heating rate is 10℃ / min and the heating time is 120 minutes, and then calcine at 1100-1300℃ for 7-9 hours under an argon atmosphere to obtain brown solid granular material. Step 6. Place the brown solid granular material obtained in Step 5 into a calcination apparatus, raise the calcination temperature from room temperature to 1100-1300℃, wherein the heating rate is 10℃ / min and the heating time is 120 minutes, and then calcine at 1100-1300℃ for 7-9 hours in an ammonia atmosphere. The resulting white porous solid material is the formaldehyde-carbon dioxide co-adsorbent.

2. The formaldehyde and carbon dioxide combined adsorption purification method as described in claim 1, characterized in that, The formaldehyde and carbon dioxide combined adsorbent comprises the following phase materials in the following mass ratios: 0.01-0.08 parts of aluminum oxide phase, 0.05-0.15 parts of pure hexagonal boron nitride phase, and 0.77-0.94 parts of aluminum-doped hexagonal boron nitride phase.

3. The formaldehyde and carbon dioxide combined adsorption purification method as described in claim 2, characterized in that, The formaldehyde and carbon dioxide combined adsorbent comprises the following phase materials in the following mass ratios: 0.03 parts of aluminum oxide phase, 0.09 parts of pure hexagonal boron nitride phase, and 0.88 parts of aluminum-doped hexagonal boron nitride phase.

4. The formaldehyde and carbon dioxide combined adsorption purification method as described in claim 1, characterized in that, The heating temperature in step 1 is 50℃.

5. The formaldehyde and carbon dioxide combined adsorption purification method as described in claim 1, characterized in that, The heating temperature in steps 2 and 4 is 90℃.

6. The formaldehyde and carbon dioxide combined adsorption purification method as described in claim 1, characterized in that, In steps 5 and 6, the calcination temperature is 1200℃ and the calcination time is 8 hours.

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