Foamed nickel-based Ni (OH) 2-organic framework composite catalyst as well as preparation method and application thereof in purifying biological aerosol

Abstract

The invention discloses a foamed nickel-based Ni (OH) 2-organic framework composite catalyst, a preparation method thereof and application of the foamed nickel-based Ni (OH) 2-organic framework composite catalyst to purification of biological aerosol, and belongs to the field of environmental catalytic materials and air purification. According to the preparation method, two-step electrochemical deposition is adopted, firstly, surface-activated foamed nickel is immersed in a Ni (NO) 3 aqueous solution for in-situ deposition of Ni (OH) 2, then the foamed nickel is immersed in a carboxylic acid ligand aqueous solution for in-situ epitaxial coordination growth of Ni MOFs, and the Ni (OH) 2-Ni MOFs nano composite catalyst is formed on the surface of the foamed nickel. The composite catalyst is adjustable in interface structure and rich in catalytic site exposure, Ni (OH) 2 provides rich initial active sites, and Ni MOFs greatly enhances the adsorption capacity to biological aerosol by virtue of a high specific surface area and a unique porous structure, and shows excellent activity and stability in the aspect of dynamic catching and killing of biological aerosol particles.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental catalytic purification, and specifically relates to a foamed nickel-based Ni(OH)2-organic framework composite catalyst, a preparation method thereof, and application in the field of bioaerosol purification. Background Art

[0002] Bioaerosols are important carriers of airborne pathogens, and their efficient, rapid, and harmless treatment is a critical need in the fields of public health and environmental safety. Catalytic oxidation, particularly photocatalytic technology, demonstrates significant potential as a highly effective and environmentally friendly method for bioaerosol purification, as it utilizes light-activated catalysts to deeply oxidize microorganisms into harmless carbon dioxide and water at room temperature.

[0003] In the prior art, the preparation of catalysts usually relies on traditional methods (such as hydrothermal method). For example, the Chinese patent publication number CN114643057A discloses a nickel-iron bimetallic oxyhydroxide composite catalyst supported on a nickel foam, which has a certain photocatalytic killing efficiency for bioaerosols. However, the catalyst is prepared by the traditional hydrothermal method, and the preparation conditions are complex and time-consuming, and it is difficult to achieve uniform growth of the catalyst. Metal organic frameworks (MOFs) materials have shown great potential in the field of catalysis with their unique porous structure, high specific surface area and adjustable chemical properties. The Chinese patent publication number CN109675639A uses N, N-dimethylformamide as solvent and trimesic acid as ligand to prepare Ni-MOF / NF catalyst on the surface of nickel foam by constant potential deposition method. It can be used for electrolysis of water for hydrogen evolution and preparation of glucaric acid at the same time. However, this method uses a large amount of toxic reagent N, N-dimethylformamide, and the potential harm to human body and environment cannot be ignored. In addition, the direct electrodeposition of MOFs on the surface of nickel foam results in too small a catalyst loading, making it difficult to provide sufficient catalytic active sites; secondly, the poor conductivity and photoresponse characteristics of MOFs seriously hinder the spatial transport of electrons and the continuous and stable progress of catalytic redox reactions. Summary of the Invention

[0004] The present invention aims to provide a nickel-based foamed Ni(OH)2-organic framework composite catalyst. By optimizing the material structure and interfacial interactions, it significantly enhances the adsorption and catalytic oxidation capabilities of bioaerosols. This catalyst can efficiently catalytically oxidize microorganisms in bioaerosols into harmless substances, thereby effectively reducing the environmental and human health hazards of bioaerosols.

[0005] The present invention also provides an in-situ electrochemical deposition method for preparing the nickel foam-based Ni(OH)2-organic framework composite catalyst. This method is simple to operate, low in cost, and amenable to large-scale production, ensuring that the prepared composite catalyst has stable and excellent performance.

[0006] The foamed nickel-based Ni(OH)2-organic framework composite catalyst provided by the present invention is prepared by the following method:

[0007] Step 1: The nickel foam is sequentially placed in acetone and ethanol to remove surface stains, then ultrasonically cleaned in dilute hydrochloric acid to remove surface oxides, and finally cleaned with deionized water and vacuum dried to obtain surface-activated nickel foam.

[0008] Step 2: Immerse the surface-activated nickel foam in a nickel nitrate aqueous solution and perform electrochemical deposition to obtain nickel foam with deposited Ni(OH)2.

[0009] Step 3: Immerse the nickel foam with deposited Ni(OH)2 in a carboxylic acid ligand aqueous solution and perform electrochemical deposition to obtain a nickel foam-based Ni(OH)2-organic framework composite catalyst.

[0010] Furthermore, in the above step 1, the concentration of the dilute hydrochloric acid is preferably 0.1 to 3 mol / L.

[0011] Furthermore, in the above step 2, the concentration of the nickel nitrate aqueous solution is preferably 0.1 to 2 mol / L.

[0012] Furthermore, in the above step 2, the carboxylic acid ligand is preferably any one of terephthalic acid, trimesic acid, and oxalic acid; and the concentration of the carboxylic acid ligand aqueous solution is 0.1 to 3 mol / L.

[0013] Furthermore, in the above steps 2 and 3, the voltage of the electrochemical deposition is 0.1 to 1.5 V, and the deposition time is 1 to 30 minutes.

[0014] Furthermore, in the above steps 2 and 3, the voltage of the electrochemical deposition is preferably 0.75 to 1.25 V, and the deposition time is 5 to 15 minutes.

[0015] The present invention also provides the use of the nickel foam-based Ni(OH)2-organic framework composite catalyst in the catalytic purification of bioaerosols, such as viral aerosols, bacterial aerosols, or fungal aerosols, providing an efficient and environmentally friendly solution for the treatment of bioaerosols.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention utilizes a two-step electrochemical deposition process, first depositing Ni(OH)2 on nickel foam, and then epitaxially growing Ni MOFs on the surface of the nickel foam-based Ni(OH)2 to construct a Ni(OH)2-Ni MOFs composite structure. This structure combines the high conductivity of Ni(OH)2 with the unique advantages of MOFs. On the one hand, Ni(OH)2 is used to provide a transport channel for photogenerated carriers and achieve a high MOF loading capacity. On the other hand, the porous structure of MOFs increases the specific surface area, improving adsorption and catalytic efficiency. Compared to traditional impregnation and hydrothermal methods, the present invention precisely controls the growth rate and deposition amount of MOFs on the surface of the nickel foam-based Ni(OH)2 by adjusting key parameters of electrochemical deposition, such as the deposition potential and deposition time. This completely solves the problems of low loading, localized agglomeration, and uneven distribution in existing methods. Traditional methods are affected by concentration gradients and thermodynamic differences, making it difficult to achieve uniform deposition on complex-shaped nickel foam surfaces. The present invention, however, utilizes electric field forces to drive the uniform migration of metal ions and organic ligands. Even when faced with a three-dimensional porous, irregularly structured nickel foam substrate, a dense and uniform MOFs coating can be formed, providing more sufficient and more reasonably distributed active sites for the catalytic reaction. Furthermore, during use, traditional MOFs catalysts are prone to problems such as loss of active sites and structural collapse due to their weak loading and loose structure, which affects the durability of the catalytic performance. The present invention achieves a close bond between MOFs, the nickel foam substrate, and Ni(OH)2 through electrochemical deposition, forming a stable three-dimensional composite structure. This structure not only enhances the overall mechanical strength of the catalyst, but also effectively resists chemical erosion during the reaction process, significantly improving the stability and service life of the catalyst, reducing replacement frequency, and lowering processing costs.

[0018] 2. The composite structure of Ni(OH)2 and Ni-MOFs constructed in this invention fully exploits the synergistic effect of the two. Ni(OH)2 provides abundant initial active sites, while Ni-MOFs, with their high specific surface area and unique porous structure, significantly enhance the adsorption capacity of bioaerosols. Simultaneously, they optimize the electron transport and migration pathways, accelerating the reaction kinetics, thereby achieving rapid oxidation and killing of bioaerosols. This solves the problem of low bioaerosol treatment efficiency caused by the slow reaction kinetics of existing catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a scanning electron microscope image of the nickel foam on which Ni(OH)2 is deposited in Example 1.

[0020] Figure 2 This is a scanning electron microscope image of the nickel foam-based Ni(OH)2-organic framework composite catalyst in Example 1.

[0021] Figure 3This is a diagram showing the killing effect of the nickel foam-based Ni(OH)2-organic framework composite catalyst on bioaerosol particles in Example 1. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and examples, but the protection scope of the present invention is not limited to these examples.

[0023] Example 1

[0024] Step 1: Immerse a 3cm×3cm nickel foam in acetone and anhydrous ethanol for 0.5h each to remove surface stains, then ultrasonically clean with 0.5mol / L dilute hydrochloric acid to remove surface oxides, and finally rinse with deionized water. Place the cleaned nickel foam in a vacuum drying oven at 60°C and dry for 12h to obtain surface-activated nickel foam.

[0025] Step 2: Immerse the surface activated nickel foam in a 0.5 mol / L Ni(NO)3 aqueous solution, perform electrochemical deposition at a voltage of 0.75 V for 10 min, and rinse with deionized water to obtain nickel foam with deposited Ni(OH)2. Figure 1 It can be seen that Ni(OH)2 nanosheets are uniformly deposited on the surface of nickel foam, indicating that the surface of nickel foam can be quickly and easily modified in situ by electrochemical deposition.

[0026] Step 3: Immerse the nickel foam with deposited Ni(OH)2 in a 0.5 mol / L terephthalic acid aqueous solution, perform electrochemical deposition at a voltage of 0.75 V for 5 min, rinse with deionized water, and dry at 60°C to obtain a nickel foam-based Ni(OH)2-organic framework (abbreviated as Ni MHOFs) composite catalyst. Figure 2 It can be seen that after the in situ deposition of Ni MOFs, the thickness of Ni(OH)2 nanosheets has increased significantly, indicating that the Ni MHOFs composite catalyst was successfully prepared in situ on the surface of nickel foam by a two-step electrochemical deposition method.

[0027] Example 2

[0028] Step 1: Immerse a 10cm×5cm nickel foam in acetone and anhydrous ethanol for 0.5h each to remove surface stains, then ultrasonically clean with 3mol / L dilute hydrochloric acid to remove surface oxides, and finally rinse with deionized water. Place the cleaned nickel foam in a vacuum drying oven at 60°C and dry for 12h to obtain surface-activated nickel foam.

[0029] Step 2: Immerse the surface-activated nickel foam in a 1 mol / L Ni(NO)3 aqueous solution, perform electrochemical deposition at a voltage of 0.75 V for 10 min, and rinse with deionized water to obtain a nickel foam with deposited Ni(OH)2.

[0030] Step 3: Immerse the nickel foam with deposited Ni(OH)2 in a 1 mol / L aqueous solution of terephthalic acid, perform electrochemical deposition at a voltage of 0.75 V for 10 min, rinse with deionized water, and dry at 80°C to obtain a nickel foam-based Ni(OH)2-organic framework composite catalyst.

[0031] Example 3

[0032] Step 1: Immerse a 2.5 cm × 2.5 cm nickel foam in acetone and anhydrous ethanol for 0.5 h each to remove surface stains, then ultrasonically clean with 0.5 mol / L dilute hydrochloric acid to remove surface oxides, and finally rinse with deionized water. Place the cleaned nickel foam in a vacuum drying oven at 60 ° C and dry for 12 h to obtain surface-activated nickel foam.

[0033] Step 2: Immerse the surface-activated nickel foam in a 1 mol / L Ni(NO)3 aqueous solution, perform electrochemical deposition at a voltage of 1.25 V for 5 minutes, and rinse with deionized water to obtain a nickel foam with deposited Ni(OH)2.

[0034] Step 3: Immerse the nickel foam with deposited Ni(OH)2 in a 1 mol / L oxalic acid aqueous solution, perform electrochemical deposition at a voltage of 1.25 V for 5 minutes, rinse with deionized water, and dry at 60°C to obtain a nickel foam-based Ni(OH)2-organic framework composite catalyst.

[0035] Example 4

[0036] Step 1: Immerse a 10cm×5cm nickel foam in acetone and anhydrous ethanol for 0.5h each to remove surface stains, then ultrasonically clean with 3mol / L dilute hydrochloric acid to remove surface oxides, and finally rinse with deionized water. Place the cleaned nickel foam in a vacuum drying oven at 60°C and dry for 12h to obtain surface-activated nickel foam.

[0037] Step 2: Immerse the surface-activated nickel foam in a 1 mol / L Ni(NO)3 aqueous solution, perform electrochemical deposition at a voltage of 1.25 V for 5 minutes, and rinse with deionized water to obtain a nickel foam with deposited Ni(OH)2.

[0038] Step 3: Immerse the nickel foam with deposited Ni(OH)2 in a 2 mol / L aqueous solution of trimesic acid, perform electrochemical deposition at a voltage of 1.25 V for 15 min, rinse with deionized water, and dry at 80°C to obtain a nickel foam-based Ni(OH)2-organic framework composite catalyst.

[0039] The foam nickel-based Ni(OH)2-organic framework composite catalyst prepared in Examples 1 to 4 was modularly assembled on the filter plate of the catalytic purification device in the bioaerosol killing performance evaluation system (authorization announcement number CN216978969U), and the concentration of 10 5 ~10 9 cfu / mL of bacterial aerosol was introduced into the aerosol, and the concentration of aerosol in the air before and after inactivation was compared. Figure 3 It can be seen that the Ni MHOFs composite catalyst prepared in Example 1 has a bacterial aerosol killing efficiency of 99.99%, which is much higher than the catalytic performance of Ni(OH)2 alone (i.e., the nickel foam deposited with Ni(OH)2 in Step 2 of Example 1) and MOFs (Ni MOFs obtained by electrochemically depositing the surface-activated nickel foam in Step 1 of Example 1 directly in Step 3). After testing, the nickel foam-based Ni(OH)2-organic framework composite catalysts prepared in Examples 2 to 4 also have a bacterial aerosol killing efficiency of over 99.99%.

[0040] The Ni MHOFs composite catalyst of Example 1 was further subjected to a cyclic catalytic performance test. The results showed that its efficiency did not decrease significantly after 4 cycles, indicating that the foamed nickel-based Ni(OH)2-organic framework composite catalyst of the present invention has great potential to become a functional material for purifying air pollutants such as bioaerosol particles.

[0041] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a foamed nickel-based Ni(OH)2-organic framework composite catalyst, characterized in that: The method comprises the following steps: Step 1: The nickel foam is sequentially placed in acetone and ethanol to remove surface stains, then ultrasonically cleaned in dilute hydrochloric acid to remove surface oxides, and finally rinsed with deionized water and vacuum dried to obtain a surface-activated nickel foam; Step 2: Immersing the surface-activated nickel foam in a nickel nitrate aqueous solution for electrochemical deposition to obtain nickel foam deposited with Ni(OH)2; Step 3: Immerse the nickel foam with deposited Ni(OH)2 in a carboxylic acid ligand aqueous solution and perform electrochemical deposition to obtain a nickel foam-based Ni(OH)2-organic framework composite catalyst.

2. The method for preparing a foamed nickel-based Ni(OH)2-organic framework composite catalyst according to claim 1, wherein: In step 1, the concentration of the dilute hydrochloric acid is 0.1 to 3 mol / L.

3. The method for preparing the nickel foam-based Ni(OH)2-organic framework composite catalyst according to claim 1, wherein: In step 2, the concentration of the nickel nitrate aqueous solution is 0.1-2 mol / L.

4. The method for preparing a foamed nickel-based Ni(OH)2-organic framework composite catalyst according to claim 1, wherein: In step 3, the carboxylic acid ligand is any one of terephthalic acid, trimesic acid, and oxalic acid; and the concentration of the carboxylic acid ligand aqueous solution is 0.1 to 3 mol / L.

5. The method for preparing the foamed nickel-based Ni(OH)2-organic framework composite catalyst according to claim 1, wherein: In step 2 and step 3, the voltage of the electrochemical deposition is 0.1 to 1.5 V, and the deposition time is 1 to 30 minutes.

6. The method for preparing the foamed nickel-based Ni(OH)2-organic framework composite catalyst according to claim 1, wherein: In step 2 and step 3, the voltage of the electrochemical deposition is 0.75 to 1.25 V, and the deposition time is 5 to 15 minutes.

7. A foamed nickel-based Ni(OH)2-organic framework composite catalyst obtained by the preparation method according to any one of claims 1 to 6.

8. Use of the foamed nickel-based Ni(OH)2-organic framework composite catalyst according to claim 7 in catalytic purification of bioaerosols.

9. Use of the foamed nickel-based Ni(OH)2-organic framework composite catalyst in catalytic purification of bioaerosols according to claim 8, characterized in that: The bioaerosol is a viral aerosol, a bacterial aerosol or a fungal aerosol.

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