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CN-122011411-A - Preparation method and application of o-trifluoromethyl benzoic acid modified Ni-Mg-MOF-74

CN122011411ACN 122011411 ACN122011411 ACN 122011411ACN-122011411-A

Abstract

The invention discloses a Metal Organic Framework (MOF) with an efficient adsorption effect, and a preparation method and application thereof, and belongs to the field of gas adsorption separation. According to the invention, the defect of solvent synthesis of the MOF material is utilized, a polar tube energy group is introduced to replace a defect group, so that an adsorption dead zone is eliminated, and the o-trifluoromethyl benzoic acid modified Ni-Mg-MOF-74 material with high-efficiency adsorption is obtained. The MOF material prepared by the invention has excellent CO 2 adsorption capacity and high CO 2 /N 2 selectivity.

Inventors

  • HUANG YAN
  • ZHANG JINHONG
  • WANG JIAWEI

Assignees

  • 北京化工大学

Dates

Publication Date
20260512
Application Date
20260209

Claims (7)

  1. 1. The application of the o-trifluoromethyl benzoic acid modified Ni-Mg-MOF-74 material in CO 2 separation is characterized in that the original defects of formate in the material are utilized, the o-trifluoromethyl benzoic acid is introduced through post-synthesis modification, formate is partially replaced, and the MOF material with polar functional groups is obtained and is marked as Ni-Mg-MOF-74-TBA.
  2. 2. The method for preparing the Ni-Mg-MOF-74-TBA material according to claim 1, wherein the preparation method comprises the steps of dispersing the dried Ni-Mg-MOF-74 and a certain mass of o-trifluoromethyl benzoic acid in 20 mL DMF respectively, stirring the two solutions uniformly, mixing the two solutions, stirring the two solutions for 2 hours, reacting the two solutions in a 70 ℃ oil bath for 24 hours, washing the product by using 100mL acetone after the reaction is finished, and finally drying the product in vacuum at 60 ℃ for 24 hours to obtain the Ni-Mg-MOF-74-TBA material.
  3. 3. The method for preparing the Ni-Mg-MOF-74-TBA as claimed in claim 2, wherein the method for synthesizing the Ni-Mg-MOF-74 precursor comprises the steps of dissolving H 4 dobdc, magnesium salt and nickel salt in a mixed solvent consisting of DMF, ethanol and water respectively, wherein the total volume of the mixed solvent is 25 mL, placing the mixed solvent in a 50 mL reaction bottle, fully dissolving the mixed solvent by ultrasonic treatment, stirring the mixed solvent for 1 hour, transferring the mixed solution into a 100mL reaction kettle liner, continuously stirring the mixed solution for 2 hours, sealing the reaction kettle, reacting for 24 hours at 135 ℃, washing the mixed solution with DMF for 2 times (3 hours each time), washing the mixed solution with methanol for 4 times (12 hours each time), collecting solid products, drying the solid products in vacuum for 24 hours at 60 ℃ to obtain the Ni-Mg-MOF-74 precursor, and activating the solid products under the vacuum condition for later use.
  4. 4. The method for preparing the MOF material Ni-Mg-MOF-74-TBA according to claim 2, wherein the mass ratio of the Ni-Mg-MOF-74 to the o-trifluoromethyl benzoic acid is 20:19.
  5. 5. The method for preparing the MOF material Ni-Mg-MOF-74-TBA according to claim 3, wherein the molar mass ratio of the nickel salt to the magnesium salt to the NiCl 2 、MgCl 2 ,NiCl 2 、MgCl 2 is 0.76:0.24, 0.54:0.46, 0.32:0.68 and 1:0.
  6. 6. The method for preparing the MOF material Ni-Mg-MOF-74-TBA according to claim 3, wherein the volume ratio of DMF/ethanol/water is 15:1:1.
  7. 7. The method for producing a MOF material Ni-Mg-MOF-74-TBA according to claim 3, wherein the vacuum activation step is carried out at 255℃for 12 hours.

Description

Preparation method and application of o-trifluoromethyl benzoic acid modified Ni-Mg-MOF-74 Technical Field The invention belongs to the field of gas adsorption separation, and particularly relates to a preparation method of o-trifluoromethyl benzoic acid modified Ni-Mg-MOF-74 and application thereof in CO 2 adsorption. Background With the development of industry, human beings have had unprecedented impact on the environment. The progress of industrialization has led to the emission of greenhouse gases. The large amount of CO 2 emissions has a great impact on the environment, such as ocean acidification, global warming, etc. Therefore, the task of reducing carbon is urgent. The majority of the emitted CO 2 is mainly from the flue gas of fossil fuel fired power plants, thus reducing the emission of CO 2 from a point source can be achieved by Carbon Capture and Storage (CCS) technology. At present, various physical adsorption materials are reported to be used for carbon dioxide adsorption, but the problems of high energy consumption, equipment corrosion and the like are faced, and compared with the traditional adsorbent, the metal organic framework has the advantages of high specific surface area, easiness in pore regulation and the like, and is widely applied to the field of gas adsorption separation. MOF-74 greatly increases the adsorption of CO 2 due to the high density of open metal sites, but therefore also results in a very easy adsorption of moisture, resulting in structural collapse. Therefore, there is a need to improve the frame water stability and high adsorption capacity. Disclosure of Invention Aiming at the problems of poor structural stability, low CO 2/N2 selectivity and the like of materials, the invention provides a preparation method of o-trifluoromethyl benzoic acid modified Ni-Mg-MOF-74 and application thereof in CO 2 adsorption by utilizing the defects of material solvent synthesis and introducing polar tube energy groups. The Ni-Mg-MOF-74-TBA of the invention enhances the stability of the material and improves the adsorption capacity of CO 2. The preparation method of the Ni-Mg-MOF-74-TBA material comprises the following steps of dispersing or dissolving dried Ni-Mg-MOF-74 and a certain mass of o-trifluoromethyl benzoic acid in 20 mL DMF respectively, stirring uniformly, mixing the two parts of solutions, stirring for 2 hours, reacting in an oil bath at 70 ℃ for 24 hours, washing a product by using 30 mL diethyl ether and 50mL acetone in sequence after the reaction is finished, and finally drying in vacuum at 60 ℃ for 24 hours to obtain the Ni-Mg-MOF-74-TBA material. Further, the method for synthesizing the Ni-Mg-MOF-74 precursor comprises the steps of respectively dissolving H 4 dobdc, magnesium salt and nickel salt in a mixed solvent consisting of DMF, ethanol and water, wherein the total volume of the mixed solvent is 25 mL, placing the mixed solvent in a 50 mL reaction bottle, fully dissolving the mixed solvent by ultrasonic treatment, stirring for 1 hour, transferring the mixed solution into a lining of a 100 mL reaction kettle, continuously stirring for 2 hours, sealing the reaction kettle, reacting for 24 hours at 135 ℃, washing the reaction kettle for 2 times by using DMF and 4 times by using methanol after the reaction is finished, collecting a solid product, and vacuum-drying the solid product for 24 hours at 60 ℃ to obtain the Ni-Mg-MOF-74 precursor for later use after activation under vacuum condition. Further, in the preparation method of the Ni-Mg-MOF-74-TBA material, the mass ratio of the Ni-Mg-MOF-74 to the o-trifluoromethyl benzoic acid is 20:19. Further, in the preparation method of the Ni-Mg-MOF-74 material, the molar mass ratio of nickel salt to magnesium salt is NiCl 2、MgCl2,NiCl2、MgCl2 and is 0.76:0.24, 0.54:0.46, 0.32:0.68 and 1:0. Further, in the preparation method of the Ni-Mg-MOF-74 material, the volume ratio of DMF/ethanol/water is 15:1:1. Further, the preparation method of the MOF material Ni-Mg-MOF-74-TBA comprises the step of activating for 12 hours at 255 ℃. The MOF material Ni-Mg-MOF-74-TBA of the invention shows excellent CO 2 adsorption performance and CO 2/N2 selectivity. (1) The saturated CO 2 adsorption amount of Ni 0.32Mg0.68 -MOF-74-TBA was 214 cm 3/g at 298K, 1 atm. (2) The specific CO 2 capture application exhibited excellent adsorption capacity, ni-Mg-MOF-74-TBA at 112: 112 mmHg pressure (post-combustion carbon dioxide capture-PC), and CO 2 adsorption amounts to 114-149: 149 cm 3/g. (3) CO 2/N2 adsorption selectivity 550 of Ni 0.32Mg0.68 -MOF-74-TBA. The Ni-Mg-MOF-74-TBA shows excellent CO 2 adsorption capacity and higher CO 2/N2 adsorption selectivity compared with the prior standard materials. Drawings FIG. 1 is a powder X-ray diffraction pattern of the precursor of examples 1-4 Ni-Mg-MOF-74. FIG. 2 is a powder X-ray diffraction pattern of examples 1-4 Ni-Mg-MOF-74-TBA. FIG. 3 is a Fourier transform infrared spectrum of the precursor of example