Method for preparing imidazole modified Cu-BTC, product and application

Abstract

The invention relates to the technical field of organic waste gas treatment, in particular to a method for preparing imidazole modified Cu-BTC, a product and application. The product synthesized by the method shows a larger specific surface area, has larger pore channels, and can effectively capture toluene; a plurality of open Cu < 2 + > sites are contained in a pore channel of a three-dimensional skeleton structure, and formaldehyde molecules can be attracted through electrostatic interaction, so that a certain formaldehyde adsorption capacity is achieved; a large amount of imidazole can be loaded by a large amount of pore channels, so that rich nitrogen-containing functional groups are provided. The imidazole modified Cu-BTC provided by the invention has better toluene and formaldehyde adsorption capacity, and has a good application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of organic waste gas treatment, and in particular to a method for preparing imidazole-modified Cu-BTC, a product and application thereof. Background Art

[0002] As industrial solvents, large-scale emissions of volatile organic compounds (VOCs) pose a serious threat to the environment and human health. VOCs are of various types with different characteristics. Aromatic compounds can be converted into secondary organic aerosols (SOA) through physical and chemical processes. Compared with primary organic aerosols (POA), SOA has higher polarity and oxidizing properties, and has a more significant impact on the environment and human health. Some VOCs such as benzene, polycyclic aromatic hydrocarbons, aromatic amines, resin compounds, aldehydes and nitrosamines are carcinogenic; while others such as certain aromatic amines, aldehydes, halogenated hydrocarbons and their derivatives, vinyl chloride, etc. may cause mutations in the liver, kidneys, brain, blood and nervous system.

[0003] Toluene, as a representative of benzene series, mainly comes from the use of organic solvents, industrial production emissions such as petrochemicals, and exhaust emissions from motor vehicles. Long-term exposure to toluene increases the risk of cancer. High-concentration exposure can cause symptoms such as irritation, nausea, dizziness and headaches. Chronic poisoning may also cause serious damage to the liver, kidneys and brain. In addition, formaldehyde, as another VOCs that has attracted much attention, is equally harmful, such as carcinogenicity and potential risk of leukemia. Formaldehyde is widely present in closed environments, such as passenger cars, airplanes, public spaces and some production workshops, making the control of indoor formaldehyde pollution an urgent task.

[0004] Metal organic framework materials (MOFs) are a new type of crystalline hybrid porous materials, which are composed of metal ions or clusters and organic ligands in an ordered one-dimensional, two-dimensional or three-dimensional framework through coordination. The organic and inorganic components of MOFs are highly variable. By introducing various functional groups to modify the monomers, more active sites can be generated. Therefore, they are widely used in the adsorption of various pollutants, especially in the field of VOCs removal. It shows great potential. Developing more MOFs with better performance is of great significance for the treatment of organic waste gas.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a synthesis method of imidazole-modified Cu-BTC with good toluene and formaldehyde adsorption capacity, and its product and application.

[0007] Specifically, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for synthesizing imidazole-modified Cu-BTC, comprising: dissolving cupric chloride dihydrate and trimesic acid in a mixed solution of N,N-dimethylformamide and deionized water, adding dilute hydrochloric acid, and mixing evenly; heating the mixture at 75-85° C. for 20-28 hours to synthesize Cu-BTC; and grinding the synthesized Cu-BTC into powder, placing the powder in a sealed container containing imidazole, and heating the mixture for reaction for 20-100 hours.

[0008] Preferably, the mass ratio of cupric chloride dihydrate to trimesic acid is 43-66:53-81.

[0009] Preferably, the synthesis method provided by the present invention further comprises washing and drying steps after heating the mixture at 75-85°C for 20-28 hours; the drying parameters are 95-105°C and 10-16h.

[0010] Preferably, the synthesis method provided by the invention comprises: dissolving cupric chloride dihydrate and trimesic acid in a mass ratio of 53-57:66-69 in a mixed solution of N,N-dimethylformamide and deionized water, adding dilute hydrochloric acid, and mixing evenly; heating the mixture at 78-82°C for 22-26 hours; drying after washing, the drying parameters being 98-102°C for 11-15 hours; then grinding the synthesized Cu-BTC into powder, placing it in a sealed container containing imidazole, and heating the reaction for 20-100 hours.

[0011] Preferably, in the present invention, based on the usage of cupric chloride dihydrate being 54.5 mg, the usage of N,N-dimethylformamide being 8-12 mL, and the usage of deionized water being 65-95 mL.

[0012] Preferably, in the present invention, based on the usage of 54.5 mg of cupric chloride dihydrate, the concentration of dilute hydrochloric acid is 0.45-0.55 mol / L, and the usage is 0.4-0.6 mL.

[0013] Further preferably, in the method for synthesizing imidazole-modified Cu-BTC provided by the present invention, the heating temperature in the sealed container containing imidazole is 115-125° C., and the reaction time is 40-60 h.

[0014] In a second aspect, the present invention provides a product synthesized by the above synthesis method.

[0015] In a third aspect, the present invention provides the use of the above product as a toluene and / or formaldehyde adsorbent.

[0016] Beneficial effects: The present invention provides a method for synthesizing imidazole-modified Cu-BTC with good toluene and formaldehyde adsorption capacity, and its products and applications. The product synthesized by the present invention exhibits a large specific surface area and has large pores, which can effectively capture toluene; the pores of its three-dimensional skeleton structure contain many open Cu 2+ The imidazole-modified Cu-BTC provided by the present invention has better toluene and formaldehyde adsorption capacity and good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be described below.

[0018] Figure 1 Schematic diagram of the synthesis of Cu-BTC used in the present invention.

[0019] Figure 2 Schematic diagram of the structure of Cu-BTC and imidazole-modified Cu-BTC used in the present invention.

[0020] Figure 3 This is the specific surface area (BET) diagram of Cu-BTC used in the present invention.

[0021] Figure 4 Scanning electron microscopy (SEM) images: (ab) Cu-BTC; (cd) imidazole-modified Cu-BTC.

[0022] Figure 5 This is the toluene adsorption isotherm of the imidazole-modified Cu-BTC of the present invention.

[0023] Figure 6 The figure is the formaldehyde adsorption isotherm of the imidazole-modified Cu-BTC of the present invention. DETAILED DESCRIPTION

[0024] Cu-BTC is a MOFs with excellent adsorption properties. + and trimesic acid, and has a three-dimensional structure (main pore diameter is 9 Å, tetrahedral side pore is 3.5 Å), as well as advantages such as high specific surface area, pore volume and adjustable structure. The present invention adopts a solvothermal method to synthesize the Cu-BTC metal organic framework material, and modifies it after synthesis by imidazole to achieve efficient removal of volatile organic compounds toluene and formaldehyde, and characterizes this.

[0025] In one of the more specific embodiments, the imidazole-modified Cu-BTC provided by the present invention is prepared by imidazole modification of Cu-BTC as the base material. The preparation method of Cu-BTC is as follows: dissolve copper chloride dihydrate (54.5 mg, 0.32 mmol) and trimesic acid (67.2 mg, 0.32 mmol) in a mixed solution of 10 mL N,N-dimethylformamide (DMF) and 80 mL deionized water, and then add about 0.5 mL of dilute hydrochloric acid (0.5 mol / L), and then ultrasonically stir the mixture for 10 minutes to completely dissolve and mix evenly, and finally heat the mixture at 80 ° C for 24 hours. After natural cooling, the obtained product is filtered and washed with DMF and deionized water. Finally, the obtained MOF material is dried in a vacuum at 100 ° C for 12 hours to obtain Cu-BTC. Based on the above Cu-BTC, the method of further imidazole modification to obtain imidazole-modified Cu-BTC is as follows: grind Cu-BTC into powder with uniform particle size, put it into a glass container, then put the glass container containing Cu-BTC into a sealed container containing imidazole, heat to 120 ° C, react for 48 hours, and then take out the material and mark it as imidazole-modified Cu-BTC. The loading amount of imidazole after modification is about 488.6 mg / g.

[0026] The Cu-BTC material provided by the present invention exhibits a large specific surface area, reaching 547.66 m 2 / g( Figure 3 ), and has large pores that can effectively capture toluene; in addition, the pores in its three-dimensional skeleton structure contain many open Cu 2+ Sites can attract formaldehyde molecules through electrostatic interaction, thus having a certain formaldehyde adsorption capacity. On this basis, a large number of pores can load a large amount of imidazole, thereby providing abundant nitrogen-containing functional groups. Therefore, after imidazole modification, better toluene and formaldehyde adsorption capacity can be obtained.

[0027] The present invention detects the morphology of the above-mentioned Cu-BTC and its imidazole-loaded Cu-BTC by scanning electron microscopy (SEM). Cu-BTC has a regular octahedral structure and a crystal particle size of about 50 μm. After imidazole is loaded, the crystal surface becomes rough and many tiny particles are attached ( Figure 4 ).

[0028] The material provided by the present invention is a modified MOF material with numerous active sites, which can be used as an adsorbent to adsorb and remove toluene and formaldehyde in the environment.

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0030] The endpoints and any values ​​of the ranges disclosed in this specification are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "specific implementations", or "some specific implementations" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0032] In the examples provided in this specification, if no specific techniques or conditions are specified, the techniques or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased through regular channels.

[0033] Example 1 This embodiment provides an imidazole-modified porous metal-organic framework compound, which is based on Cu-BTC and is further modified with imidazole to obtain imidazole-modified Cu-BTC.

[0034] This embodiment provides a method for synthesizing Cu-BTC, the steps of which are: dissolving cupric chloride dihydrate (54.5 mg, 0.32 mmol) and trimesic acid (67.2 mg, 0.32 mmol) in a mixed solution of 10 mL N,N-dimethylformamide (DMF) and 80 mL deionized water, adding about 0.5 mL of dilute hydrochloric acid (0.5 mol / L), and then ultrasonically stirring the mixture for 10 minutes to completely dissolve and mix evenly, and finally heating the mixture at 80 ° C for 24 hours. After natural cooling, the obtained product is filtered and washed with DMF and deionized water. Finally, the obtained MOF material is dried in a vacuum at 100 ° C for 12 hours to obtain Cu-BTC.

[0035] This embodiment provides a method for synthesizing imidazole-modified Cu-BTC, comprising the steps of grinding Cu-BTC into a powder having uniform particle size, placing the powder into a glass vessel, placing the glass vessel containing Cu-BTC into a sealed container containing imidazole, heating to 120° C. for reaction for 48 hours, and then taking out the material and marking it as imidazole-modified Cu-BTC.

[0036] Example 2 This embodiment provides an imidazole-modified porous metal-organic framework compound, which is based on Cu-BTC and is further modified with imidazole to obtain imidazole-modified Cu-BTC.

[0037] The synthesis method of Cu-BTC in this embodiment is the same as that in Example 1.

[0038] This embodiment provides a method for synthesizing imidazole-modified Cu-BTC, comprising the steps of grinding Cu-BTC into a powder having a uniform particle size, placing the powder into a glass container, placing the glass container containing Cu-BTC into a sealed container containing imidazole, heating to 125° C. for reaction for 40 hours, and then taking out the material and marking it as imidazole-modified Cu-BTC.

[0039] Example 3 This embodiment provides an imidazole-modified porous metal-organic framework compound, which is based on Cu-BTC and is further modified with imidazole to obtain imidazole-modified Cu-BTC.

[0040] The synthesis method of Cu-BTC in this embodiment is the same as that in Example 1.

[0041] This embodiment provides a method for synthesizing imidazole-modified Cu-BTC, comprising the steps of grinding Cu-BTC into a powder having uniform particle size, placing the powder into a glass container, placing the glass container containing Cu-BTC into a sealed container containing imidazole, heating to 115° C. for reaction for 60 hours, and then taking out the material and marking it as imidazole-modified Cu-BTC.

[0042] Example 4 This example takes the imidazole-modified Cu-BTC provided in Example 3 as an example, and provides its application in the adsorption of toluene and formaldehyde.

[0043] The application method provided in this embodiment comprises the following steps: the imidazole-modified Cu-BTC synthesized in Example 4 is ground into a uniform powder in an agate mortar. Then 50 mg of the ground imidazole-modified Cu-BTC powder is weighed and added to a glass vessel. Afterwards, the glass vessel containing the imidazole-modified Cu-BTC powder is placed in sealed containers containing toluene and formaldehyde, respectively, and placed in a 55°C oven for reaction. The weight is weighed and the adsorption curve changes are recorded at given time intervals by a weighing method.

[0044] The experimental results show that imidazole-modified Cu-BTC exhibits excellent adsorption performance, with an adsorption capacity of 172.62 mg / g for toluene and 78.63 mg / g for formaldehyde. In contrast, the adsorption capacity of unmodified Cu-BTC for toluene and formaldehyde is 74.68 mg / g and 74.07 mg / g, respectively (see Figure 5 and Figure 6 ). This shows that the imidazole-modified Cu-BTC can effectively improve the adsorption capacity of the material for toluene and formaldehyde.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synthesizing imidazole-modified Cu-BTC, characterized in that: include: Dissolve cupric chloride dihydrate and trimesic acid in a mixed solution of N,N-dimethylformamide and deionized water, add dilute hydrochloric acid, and mix well; heat the mixture at 75-85°C for 20-28 hours to synthesize Cu-BTC; grind the synthesized Cu-BTC into powder, place it in a sealed container containing imidazole, and heat it for reaction for 20-100 hours.

2. The method for synthesizing imidazole-modified Cu-BTC according to claim 1, characterized in that: The mass ratio of cupric chloride dihydrate to trimesic acid is 43-66:53-81.

3. The synthetic method of imidazole-modified Cu-BTC according to claim 1 or 2, characterized in that: After the mixture is heated at 75-85°C for 20-28 hours, washing and drying steps are also included; the drying parameters are 95-105°C, 10-16 hours.

4. The method for synthesizing imidazole-modified Cu-BTC according to any one of claims 1 to 3, characterized in that: include: Dissolve copper chloride dihydrate and trimesic acid in a mass ratio of 53-57:66-69 in a mixed solution of N,N-dimethylformamide and deionized water, add dilute hydrochloric acid, and mix evenly; heat the mixture at 78-82°C for 22-26 hours; wash and dry, and the drying parameters are 98-102°C for 11-15 hours; then grind the synthesized Cu-BTC into powder, place it in a sealed container containing imidazole, and heat it for reaction for 20-100 hours.

5. The method for synthesizing imidazole-modified Cu-BTC according to any one of claims 1 to 4, characterized in that: Based on the usage of 54.5 mg of cupric chloride dihydrate, the usage of N,N-dimethylformamide is 8-12 mL, and the usage of deionized water is 65-95 mL.

6. The method for synthesizing imidazole-modified Cu-BTC according to any one of claims 1 to 5, characterized in that: Based on the usage of 54.5 mg of cupric chloride dihydrate, the concentration of dilute hydrochloric acid is 0.45-0.55 mol / L, and the usage is 0.4-0.6 mL.

7. The method for synthesizing imidazole-modified Cu-BTC according to any one of claims 1 to 6, characterized in that: The heating temperature in the sealed container containing imidazole is 115-125°C, and the reaction time is 40-60h.

8. The product synthesized by the synthesis method according to any one of claims 1 to 7.

9. Use of the product according to claim 8 as a toluene and / or formaldehyde adsorbent.

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