Process for the preparation of imidazol modified cu-btc, products and uses thereof

Abstract

The present application relates to the technical field of organic waste gas treatment, and particularly relates to a method for preparing imidazole-modified Cu-BTC, a product and application thereof. The product synthesized by the present application has a large specific surface area and a large pore, and can effectively capture toluene; the three-dimensional skeleton structure of the product contains many open Cu 2+ sites in the pore, can attract formaldehyde molecules through electrostatic action, thereby having a certain formaldehyde adsorption capacity; a large number of pores can load a large amount of imidazole, thereby providing abundant nitrogen-containing functional groups. The imidazole-modified Cu-BTC provided by the present application has better toluene and formaldehyde adsorption capacity, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic waste gas treatment, and particularly relates to a method for preparing imidazole-modified Cu-BTC, a product and application thereof. BACKGROUND

[0002] As industrial solvents, volatile organic compounds (VOCs) are discharged in large quantities, which poses a serious threat to the environment and human health. VOCs are diverse in types and vary in characteristics. Aromatic hydrocarbons among VOCs can be converted into secondary organic aerosols (SOA) through physical and chemical processes. Compared with primary organic aerosols (POA), SOA has higher polarity and oxidizability, and has 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; and others such as certain aromatic amines, aldehydes, halogenated hydrocarbons and their derivatives, and chloroethylene may cause mutation reactions of human liver, kidney, 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 petroleum chemical industry, and motor vehicle exhaust emissions. Long-term exposure to toluene increases the risk of cancer, and high concentration exposure can cause symptoms such as irritation, nausea, dizziness and headache. Chronic poisoning may also cause serious damage to liver, kidney and brain. In addition, formaldehyde, as another VOCs that attracts much attention, is also very harmful, such as carcinogenic and potential leukemia risk. Formaldehyde exists widely in enclosed environments such as passenger cars, airplanes, public spaces and some production workshops, making it an urgent task to control indoor formaldehyde pollution.

[0004] Metal-organic frameworks (MOFs) are a new type of crystalline hybrid porous material, which is composed of metal ions or clusters and organic ligands through coordination in an ordered one-dimensional, two-dimensional or three-dimensional framework. The organic and inorganic components of MOFs have high variability, and more active sites can be generated by introducing various functional group modified monomers, so MOFs are widely used in the adsorption of various pollutants, and particularly show great potential in the field of VOCs removal. It is of great significance to develop more MOFs with better performance for organic waste gas treatment.

[0005] Therefore, the present application is provided. SUMMARY

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

[0007] Specifically, the technical solutions of the present application are as follows:

[0008] In a first aspect, the present application provides a synthesis method of imidazole-modified Cu-BTC, comprising: dissolving copper chloride dihydrate and trimesic acid in a mixed solution of N,N-dimethylformamide and deionized water, adding dilute hydrochloric acid, and mixing uniformly; placing the mixture in 75-85℃ for 20-28 hours to synthesize Cu-BTC; and grinding the synthesized Cu-BTC into powder and placing it in a sealed container containing imidazole for heating reaction for 20-100 hours.

[0009] Preferably, the mass ratio of copper chloride dihydrate to trimesic acid is 43-66:53-81.

[0010] Preferably, the synthesis method provided by the present application further comprises washing and drying steps after the mixture is heated at 75-85℃ for 20-28 hours; and the drying parameters are 95-105℃ for 10-16 hours.

[0011] Preferably, the synthesis method provided by the present application comprises: dissolving copper chloride dihydrate and trimesic acid in a mixed solution of N,N-dimethylformamide and deionized water at a mass ratio of 53-57:66-69, adding dilute hydrochloric acid, and mixing uniformly; placing the mixture in 78-82℃ for 22-26 hours; and drying after washing, with the drying parameters being 98-102℃ for 11-15 hours; and grinding the synthesized Cu-BTC into powder and placing it in a sealed container containing imidazole for heating reaction for 20-100 hours.

[0012] Preferably, in the present application, the amount of N,N-dimethylformamide is 8-12 mL and the amount of deionized water is 65-95 mL, based on the amount of copper chloride dihydrate being 54.5 mg.

[0013] Preferably, in the present application, the concentration of dilute hydrochloric acid is 0.45-0.55 mol / L and the amount is 0.4-0.6 mL, based on the amount of copper chloride dihydrate being 54.5 mg.

[0014] Further preferably, the synthesis method of imidazole-modified Cu-BTC provided by the present application has a heating temperature of 115-125℃ and a reaction time of 40-60 hours in the sealed container containing imidazole.

[0015] In a second aspect, the present application provides a product synthesized by the above synthesis method.

[0016] In a third aspect, the present application provides an application of the above product as a toluene and / or formaldehyde adsorbent.

[0017] Beneficial effects:

[0018] The application provides a synthesis method of imidazole modified Cu-BTC with good toluene and formaldehyde adsorption capacity, a product thereof and application. 2+ The synthesized product has a large specific surface area and large pores, can effectively capture toluene, contains many open Cu 2+ sites in the three-dimensional skeleton structure of the pores, can attract formaldehyde molecules through electrostatic action, thereby having a certain formaldehyde adsorption capacity, and a large number of pores can load a large amount of imidazole, thereby providing abundant nitrogen-containing functional groups. The imidazole modified Cu-BTC provided by the application has better toluene and formaldehyde adsorption capacity, and has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the application or prior art, the drawings needed to be used in the embodiments or prior art description will be described below.

[0020] Figure 1 The synthesis schematic diagram of Cu-BTC used in the application.

[0021] Figure 2 The structure schematic diagram of Cu-BTC and imidazole modified Cu-BTC used in the application.

[0022] Figure 3 The specific surface area (BET) diagram of Cu-BTC used in the application.

[0023] Figure 4 The scanning electron microscope (SEM) diagram: (a-b) Cu-BTC; (c-d) imidazole modified Cu-BTC.

[0024] Figure 5 The adsorption toluene isotherm curve diagram of imidazole modified Cu-BTC in the application.

[0025] Figure 6 The adsorption formaldehyde isotherm curve diagram of imidazole modified Cu-BTC in the application. DETAILED DESCRIPTION

[0026] Cu-BTC is a MOFs with excellent adsorption properties, which is constructed by Cu²⁺ and trimesic acid, has a three-dimensional structure (main pore diameter is 9 Å, tetrahedral side pore is 3.5 Å), and has the advantages of high specific surface area, pore volume and adjustable structure. The application synthesizes Cu-BTC metal organic framework material by using solvent thermal method, and modifies by imidazole after synthesis, so as to realize efficient removal of volatile organic compounds toluene and formaldehyde, and the application performs characterization.

[0027] In a more specific embodiment, the imidazole-modified Cu-BTC is prepared by modifying Cu-BTC with imidazole. The Cu-BTC is prepared by dissolving 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 of N,N-dimethylformamide (DMF) and 80 mL of deionized water, adding about 0.5 mL of dilute hydrochloric acid (0.5 mol / L), then ultrasonically stirring the mixture for 10 minutes to completely dissolve and uniformly mix, and finally heating the mixture at 80 ℃ 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 at 100 ℃ in vacuum for 12 hours to obtain Cu-BTC. The imidazole-modified Cu-BTC is prepared by further modifying the above Cu-BTC with imidazole, that is, grinding the Cu-BTC into a powder with uniform particle size, placing it in a glass container, placing the glass container containing the Cu-BTC into a sealed container containing imidazole, heating to 120 ℃, and reacting for 48 hours, and then taking out the material and marking it as imidazole-modified Cu-BTC. The loading amount of imidazole after modification is about 488.6 mg / g.

[0028] The Cu-BTC material provided by the present application has a large specific surface area of 547.66 m 2 / g Figure 3 , and has large pores that can effectively capture toluene; in addition, it contains many open Cu 2+ sites in the three-dimensional framework structure of the pores, which can attract formaldehyde molecules through electrostatic interaction, thereby having a certain formaldehyde adsorption capacity. On this basis, a large number of pores can load a large amount of imidazole, thereby providing a large number of nitrogen-containing functional groups, so that the imidazole-modified Cu-BTC has better toluene and formaldehyde adsorption capacity.

[0029] The present application detects the morphology of the above Cu-BTC and the imidazole-loaded Cu-BTC by scanning electron microscopy (SEM). The Cu-BTC has a regular octahedral structure, and the crystal particle size is about 50 μm; after loading imidazole, the crystal surface becomes rough and is attached with many small particles. Figure 4 .

[0030] The above material provided by the present application is a modified MOF material with a large number of active sites, which can be used as an adsorbent for adsorbing and removing toluene and formaldehyde in the environment.

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "specific implementation," or "some specific implementations," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0034] In the embodiments provided in this specification, unless specific techniques or conditions are specified, the techniques or conditions described in the literature in this field, or the product instructions, shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0035] Example 1

[0036] This embodiment provides an imidazole-modified porous metal-organic framework compound, which is an imidazole-modified Cu-BTC obtained by further imidazole modification based on Cu-BTC.

[0037] This embodiment provides a method for synthesizing Cu-BTC, comprising the following steps: dissolving 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, then adding approximately 0.5 mL of dilute hydrochloric acid (0.5 mol / L). The mixture is then ultrasonically stirred for 10 minutes to ensure complete dissolution and homogeneity. Finally, the mixture is heated at 80 °C for 24 hours. After natural cooling, the resulting product is filtered and washed with DMF and deionized water. Finally, the obtained MOF material is dried under vacuum at 100 °C for 12 hours to obtain Cu-BTC.

[0038] This embodiment provides a method for synthesizing imidazole-modified Cu-BTC. The steps are as follows: Cu-BTC is ground into a powder with uniform particle size, placed in a glass container, and then the glass container containing Cu-BTC is placed into a sealed container containing imidazole. The mixture is heated to 120 °C and reacted for 48 hours. The material is then taken out and labeled as imidazole-modified Cu-BTC.

[0039] Example 2

[0040] This embodiment provides an imidazole-modified porous metal-organic framework compound, which is an imidazole-modified Cu-BTC obtained by further imidazole modification based on Cu-BTC.

[0041] The synthesis method of Cu-BTC in this embodiment is the same as that in Embodiment 1.

[0042] This embodiment provides a method for synthesizing imidazole-modified Cu-BTC. The steps are as follows: Cu-BTC is ground into a powder with uniform particle size, placed in a glass container, and then the glass container containing Cu-BTC is placed into a sealed container containing imidazole. The mixture is heated to 125 °C and reacted for 40 hours. The material is then taken out and labeled as imidazole-modified Cu-BTC.

[0043] Example 3

[0044] This embodiment provides an imidazole-modified porous metal-organic framework compound, which is an imidazole-modified Cu-BTC obtained by further imidazole modification based on Cu-BTC.

[0045] The synthesis method of Cu-BTC in this embodiment is the same as that in Embodiment 1.

[0046] This embodiment provides a method for synthesizing imidazole-modified Cu-BTC. The steps are as follows: Cu-BTC is ground into a powder with uniform particle size, placed in a glass container, and then the glass container containing Cu-BTC is placed into a sealed container containing imidazole. The mixture is heated to 115 °C and reacted for 60 hours. The material is then taken out and labeled as imidazole-modified Cu-BTC.

[0047] Example 4

[0048] This embodiment uses the imidazole-modified Cu-BTC provided in Example 3 as an example to demonstrate its application in the adsorption of toluene and formaldehyde.

[0049] The application method provided in this embodiment is as follows: 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 container. Next, the glass container containing the imidazole-modified Cu-BTC powder is placed into sealed containers containing toluene and formaldehyde respectively, and then placed together in a 55 °C oven for reaction. The adsorption curve changes are recorded by weighing at given time intervals.

[0050] Experimental results showed that imidazole-modified Cu-BTC exhibited 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 capacities of unmodified Cu-BTC for toluene and formaldehyde were 74.68 mg / g and 74.07 mg / g, respectively (see [link to study]). Figure 5 and Figure 6 This indicates that the imidazole-modified Cu-BTC can effectively improve the material's adsorption capacity for toluene and formaldehyde.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The application of imidazole-modified Cu-BTC as a toluene or formaldehyde adsorbent, characterized in that, The method for synthesizing imidazole-modified Cu-BTC includes: dissolving copper chloride dihydrate and trimesic acid in a mixed solution of N,N-dimethylformamide and deionized water, adding dilute hydrochloric acid, and mixing thoroughly; heating the mixture at 75-85°C for 20-28 hours to synthesize Cu-BTC; then grinding the synthesized Cu-BTC into powder, placing it in a sealed container containing imidazole, and heating the reaction for 20-100 hours.

2. The application of the imidazole-modified Cu-BTC according to claim 1 as a toluene or formaldehyde adsorbent, characterized in that, The mass ratio of copper chloride dihydrate to pyromellitic acid is 43-66:53-81.

3. The application of imidazole-modified Cu-BTC as a toluene or formaldehyde adsorbent according to claim 1 or 2, characterized in that, After heating the mixture at 75-85°C for 20-28 hours, the process also includes washing and drying steps; the drying parameters are 95-105°C for 10-16 hours.

4. The application of the imidazole-modified Cu-BTC according to claim 3 as a toluene or formaldehyde adsorbent, 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 well; heat the mixture at 78-82℃ for 22-26 hours; wash and dry at 98-102℃ for 11-15 hours.

5. The application of the imidazole-modified Cu-BTC according to any one of claims 1-2, 4 as a toluene or formaldehyde adsorbent, characterized in that, Based on a dosage of 54.5 mg of copper chloride dihydrate, the dosage of N,N-dimethylformamide is 8-12 mL, and the dosage of deionized water is 65-95 mL.

6. The application of the imidazole-modified Cu-BTC according to claim 3 as a toluene or formaldehyde adsorbent, characterized in that, Based on a dosage of 54.5 mg of copper chloride dihydrate, the dosage of N,N-dimethylformamide is 8-12 mL, and the dosage of deionized water is 65-95 mL.

7. The application of the imidazole-modified Cu-BTC according to any one of claims 1-2, 4, 6 as a toluene or formaldehyde adsorbent, characterized in that, Based on a dosage of 54.5 mg of copper chloride dihydrate, the concentration of dilute hydrochloric acid is 0.45-0.55 mol / L, and the dosage is 0.4-0.6 mL.

8. The application of the imidazole-modified Cu-BTC according to claim 3 as a toluene or formaldehyde adsorbent, characterized in that, Based on a dosage of 54.5 mg of copper chloride dihydrate, the concentration of dilute hydrochloric acid is 0.45-0.55 mol / L, and the dosage is 0.4-0.6 mL.

9. The application of the imidazole-modified Cu-BTC according to claim 5 as a toluene or formaldehyde adsorbent, characterized in that, Based on a dosage of 54.5 mg of copper chloride dihydrate, the concentration of dilute hydrochloric acid is 0.45-0.55 mol / L, and the dosage is 0.4-0.6 mL.

10. The application of the imidazole-modified Cu-BTC according to any one of claims 1-2, 4, 6, 8-9 as a toluene or formaldehyde adsorbent, characterized in that, The heating temperature in the sealed container containing imidazole is 115-125℃, and the reaction time is 40-60h.

11. The application of the imidazole-modified Cu-BTC according to claim 3 as a toluene or formaldehyde adsorbent, characterized in that, The heating temperature in the sealed container containing imidazole is 115-125℃, and the reaction time is 40-60h.

12. The application of the imidazole-modified Cu-BTC according to claim 5 as a toluene or formaldehyde adsorbent, characterized in that, The heating temperature in the sealed container containing imidazole is 115-125℃, and the reaction time is 40-60h.

13. The application of the imidazole-modified Cu-BTC according to claim 7 as a toluene or formaldehyde adsorbent, characterized in that, The heating temperature in the sealed container containing imidazole is 115-125℃, and the reaction time is 40-60h.

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