Novel metal organic framework material for C2H2 / CO2 separation and preparation method thereof

Abstract

The invention belongs to the technical field of resources and environments, and particularly relates to a novel metal organic framework material for C2H2 / CO2 separation and a preparation method of the novel metal organic framework material. According to the preparation method, formic acid molecules in an MOF-808Zr6 cluster are replaced by TA (tartaric acid) through a post-synthesis modification means, and a TA functionalized MOF material, namely MOF-808-TA, is obtained. The MOF-808-TA shows high affinity to C2H2 under the conditions of 298 K and 1 bar, and the capturing capacity of a specific confinement space to C2H2 is verified in one step through a single-component adsorption isotherm and a dynamic penetration experiment. The MOF-808-TA can be applied to C2H2 / CO2 mixed gas separation due to high stability, simple synthesis, excellent thermodynamic selectivity and excellent dynamic separation capacity.

Description

Technical Field

[0001] The present invention belongs to the technical field of resources and environment, and specifically relates to a novel metal-organic framework material, a preparation method thereof, and the separation of a mixed gas of carbon dioxide and acetylene. Background Technique

[0002] As a clean energy carrier, low hydrocarbon gases have attracted increasing attention in industrial and daily production due to their advantages of high calorific value and low carbon emissions. Among them, acetylene (C2H2) is an important basic raw material and fuel in the electronics and petrochemical industries. As the simplest unsaturated hydrocarbon compound, its unique and very active carbon-carbon triple bond can participate in addition reactions to produce various compounds with added value. The industrial preparation of C2H2 is mainly through the cracking of hydrocarbons or the partial combustion of natural gas, and carbon dioxide (CO2) needs to be removed as the main impurity. Therefore, the separation of C2H2 / CO2 to produce high-purity C2H2 is of great significance in industry. At present, the processes for separating and purifying C2H2 from other gases mainly include cryogenic distillation, partial hydrogenation, or solvent extraction, and these technologies often have high energy consumption or pollution. In contrast, physical adsorption using non-thermally driven porous materials is more energy-efficient and environmentally friendly. These problems all require further research and exploration. Therefore, it is crucial to develop metal-organic framework adsorbents with good separation performance for C2H2 / CO2 and stability and selectivity.

[0003] MOFs are porous organic coordination polymers formed by the coordination self-assembly of metal ions and organic ligands. MOF crystal materials have a series of advantages such as high specific surface area, large pore volume, adjustable pore size, functionalizable pore channels, and strong designability. These advantages make MOF crystal materials have unparalleled advantages compared with traditional adsorption materials. The present invention synthesizes a novel adsorbent MOF-808-TA by the post-synthetic exchange method, and then explores the CO2 / C2H2 separation performance of MOF-808-TA. It has important guiding significance for the design and development of metal-organic framework adsorbents for separating CO2 / C2H2 and purifying C2H2, and provides an effective and general idea. Summary of the Invention

[0004] The object of the present invention is to prepare a novel metal-organic framework material based on MOF-808-TA (TA = tartaric acid), and its special three-dimensional framework increases the reaction area and is more conducive to the subsequent reaction.

[0005] The technical solution adopted by the present invention is as follows:

[0006] Based on the MOF-808-TA metal-organic framework material, its preparation method includes the following steps:

[0007] 1) Preparation of MOF-808:

[0008] 1.1) Add ZrOCl2·8H2O, trimesic acid and DMF into a beaker. After stirring for 10 - 20 min until fully dissolved, add formic acid and continue stirring for 20 - 30 min;

[0009] 1.2) Place the mixed solution obtained in step 1.1) into a reaction kettle and heat it at 110 - 120 °C for 48 - 50 h;

[0010] 1.3) After the reaction, slowly cool the obtained white solution to room temperature;

[0011] 1.4) Use deionized water, DMF and ethanol for centrifugal cleaning 3 - 4 times, and then dry the sample in an oven at 60 - 70 °C for 20 - 24 h to obtain a white MOF - 808 sample;

[0012] 2) Activation: Soak the MOF - 808 prepared in step 1) in acetone for 2 - 3 days, and then activate it in an oven at 60 - 70 °C for 5 - 6 h to obtain activated MOF - 808.

[0013] Preferably, in the above - mentioned preparation method of the MOF - 808 - TA metal - organic framework material, in step 1.1), the addition amount of ZrOCl2·8H2O is 0.253 - 0.263 g, the addition amount of trimesic acid is 0.051 - 0.061 g, the dosage of DMF is 10 - 15 mL, and the dosage of formic acid is 12 mL.

[0014] The above - mentioned application of the MOF - 808 metal - organic framework material in C2H2 / CO2 separation.

[0015] Furthermore, for the above - mentioned application of the MOF - 808 metal - organic framework material in C2H2 / CO2 separation, the method is as follows: Take the MOF - 808 metal - organic framework material and separate the mixed gas under the atmosphere of a mixed gas with a C2H2 / CO2 volume ratio of 50:50 at 298 K and 2 mL / min.

[0016] For the MOF - 808 - TA metal - organic framework material, its preparation method includes the following steps:

[0017] 1) Preparation of MOF - 808 - TA:

[0018] 1.1) Add tartaric acid into water and stir for 10 - 20 min. After fully dissolving, add the MOF - 808 metal - organic framework material and stir for 10 - 20 min for dissolution;

[0019] 1.2) Stir the mixed solution obtained in step 1.1) continuously at 60 - 70 °C for 24 - 26 h;

[0020] 1.3) After the reaction, centrifuge 3 - 4 times with deionized water to wash away the unreacted tartaric acid, and then dry the sample in an oven at 90 - 100 °C for 20 - 24 h to obtain a white MOF - 808 - TA sample;

[0021] 2) Activation: Immerse the MOF - 808 - TA prepared in step 1) in acetone for 2 - 3 days, and then activate it in an oven at 60 - 70 °C for 5 - 6 h to obtain activated MOF - 808 - TA.

[0022] Preferably, in the preparation method of the above - mentioned MOF - 808 - TA metal - organic framework material, in step 1.1), the addition amount of tartaric acid is 0.17 - 0.21 g, the amount of water used is 10 - 15 mL, and the addition amount of the MOF - 808 metal - organic framework material is 0.13 - 0.17 g.

[0023] The application of the above - mentioned MOF - 808 - TA metal - organic framework material in C2H2 / CO2 separation.

[0024] Further, for the application of the above - mentioned MOF - 808 - TA metal - organic framework material in C2H2 / CO2 separation, the method is as follows: Take the MOF - 808 - TA metal - organic framework material and separate the mixed gas under the atmosphere of a mixed gas with a C2H2 / CO2 volume ratio of 50:50 at 288 K, 2 mL / min under dry conditions.

[0025] Compared with the prior art, it has the following beneficial effects: The pore functionalization of MOFs materials is a mature strategy to meet specific separation requirements, but there are inherent limitations in adding functional groups to MOFs through in - situ strategies during the synthesis process, and the available range of functional groups is relatively limited. The post - synthesis modification method has developed into a successful method to design and expand MOFs based on pre - constructed materials, and has shown its versatility in various application fields such as catalysis, adsorption, and drug delivery. Therefore, the research on the preparation of metal - organic framework materials, the post - synthesis modification of functional groups, and the gas adsorption and separation performance is a crucial link in better exploring and developing more types of metal - organic framework materials in the future and has great application prospects. Description of the Drawings

[0026] Figure 1 It is the infrared radiation test chart of the MOF - 808 and MOF - 808 - TA metal - organic framework materials synthesized by the present invention.

[0027] Figure 2Single-component adsorption curves of CO2 and C2H2 at 273K and 298K respectively for the MOF-808 and MOF-808-TA metal-organic framework materials synthesized in the present invention.

[0028] Figure 3 Powder X-ray diffraction (PXRD) patterns of the MOF-808 and MOF-808-TA metal-organic framework materials synthesized in the present invention.

[0029] Figure 4 Breakthrough curves of the MOF-808 and MOF-808-TA metal-organic framework materials synthesized in the present invention at 298K and 2 mL / min.

[0030] Figure 5 Breakthrough curves of the MOF-808-TA metal-organic framework material synthesized in the present invention at 288K, 298K, and 308K respectively.

[0031] Figure 6 Breakthrough curves of the MOF-808-TA metal-organic framework material synthesized in the present invention at 2 mL / min, 3 mL / min, and 4 mL / min respectively.

[0032] Figure 7 Breakthrough curves of the MOF-808-TA metal-organic framework material synthesized in the present invention at 298K and 2 mL / min in dry and humid environments respectively.

[0033] Figure 8 Breakthrough curves of three groups of MOF-808-TA metal-organic framework materials synthesized in the present invention at 298K and 2 mL / min.

[0034] Figure 9 Specific surface area diagrams of the MOF-808 and MOF-808-TA metal-organic framework materials synthesized in the present invention.

[0035] Figure 10 Pore size distribution diagrams of the MOF-808 and MOF-808-TA metal-organic framework materials synthesized in the present invention. Specific embodiments

[0036] Example 1: MOF-808 metal-organic framework material

[0037] 1) Add 0.258 g of ZrOCl2·8H2O, 0.056 g of trimesic acid and 12 mL of DMF into a beaker. After stirring for 10 min to fully dissolve, add 12 mL of formic acid and continue stirring for 30 min. Then heat it at 120 °C for 48 h. After the reaction, cool the obtained white solution to room temperature at a cooling rate of 5 °C·h -1 and centrifuge and wash it three times with deionized water, DMF and ethanol respectively. Then dry the sample in an oven at 60 °C for 24 h to obtain a white MOF-808 sample.

[0038] 2) Activation: To remove the solvent molecules in the pores of the material to obtain an activated MOF-808 metal-organic framework material, the MOF-808 metal-organic framework material is activated by the solvent exchange method. Immerse 300 mg of the synthesized MOF-808 in acetone for 72 h, and then place it in an oven at 60 °C for 6 h to obtain the activated MOF-808, which is the MOF-808 metal-organic framework material.

[0039] Example 2 Based on MOF-808-TA Metal-Organic Framework Material

[0040] 1) Add 0.19 g of tartaric acid into 10 mL of water and stir for 10 min to dissolve. Then add 0.15 g of the activated MOF-808 and stir for 10 min to dissolve. Then stir at 70 °C for 24 h. After the reaction, wash away the unreacted tartaric acid with deionized water, and then dry the sample in an oven at 90 °C for 24 h to obtain a white MOF-808-TA sample.

[0041] 2) Activation: To remove the solvent molecules in the pores of the material to obtain an activated MOF-808-TA metal-organic framework material, the MOF-808-TA metal-organic framework material is activated by the solvent exchange method. Immerse 300 mg of the synthesized MOF-808-TA in acetone for 72 h, and then place it in an oven at 60 °C for 6 h to obtain the activated MOF-808-TA, which is the MOF-808-TA metal-organic framework material.

[0042] Example 3 Infrared Study of MOF-808 and MOF-808-TA Metal-Organic Framework Materials

[0043] According to Figure 1 The characteristic peak shown at 1646.937 cm -1 is for the carboxyl group. Figure 1 This is the infrared radiation test chart of the MOF-808 metal-organic framework material synthesized in Example 1 and the MOF-808-TA metal-organic framework material in Example 2.

[0044] Example 4 X-ray Diffraction Study of MOF-808 and MOF-808-TA Metal-Organic Framework Materials

[0045] According to Figure 3 In [reference], the peak intensities shown by the MOF-808 metal-organic framework material at 4.26091°, 8.2924°, 8.68085°, 10.0293° and the MOF-808-TA metal-organic framework material at 4.28734°, 8.2311°, 8.59891°, 9.94756° respectively are consistent with the theoretical data of the MOF-808 and MOF-808-TA metal-organic framework materials. Figure 3 It is the X-ray diffraction pattern of the MOF-808 metal-organic framework material synthesized in Example 1 and the MOF-808-TA metal-organic framework material in Example 2.

[0046] Example 5 Application of MOF-808 and MOF-808-TA Metal-Organic Framework Materials in C2H2 / CO2 Separation

[0047] The specific method steps are as follows:

[0048] Take 1.2 g of the MOF-808 metal-organic framework material prepared in Example 1 and complete the penetration simulation of C2H2 / CO2 on a dynamic gas penetration device. Under the mixed gas atmosphere with a C2H2 / CO2 volume ratio of 50:50, the separation performance and separation cycle stability of the material were tested at 298 K and 2 mL / min.

[0049] Take 1.2 g of the MOF-808-TA metal-organic framework material prepared in Example 2 and complete the penetration simulation of C2H2 / CO2 on a dynamic gas penetration device. Under the mixed gas atmosphere with a C2H2 / CO2 volume ratio of 50:50, the separation performance and separation cycle stability of the material were tested under different conditions of 298 K, 2 mL / min; 298 K, 3 mL / min; 298 K, 4 mL / min; 288 K, 2 mL / min; 308 K, 2 mL / min; 298 K, 2 mL / min, dry; 298 K, 2 mL / min, wet respectively. It should be noted that after each penetration, regeneration can be completed only by purging with helium at 10 mL / min at 80 °C, demonstrating the excellent regenerable performance of the material.

[0050] Example 6 Adsorption Study of MOF-808 and MOF-808-TA Metal-Organic Framework Materials for C2H2 / CO2

[0051] According to Figure 2It is clearly seen that the adsorption effect based on the MOF-808-TA metal-organic framework material is significantly better than that based on the MOF-808 metal-organic framework material. Figure 2 Single-component adsorption curves of CO2 and C2H2 of the MOF-808 metal-organic framework material synthesized in Example 1 and the MOF-808-TA metal-organic framework material in Example 2 at 273K and 298K respectively.

[0052] Study on the C2H2 / CO2 separation performance of the MOF-808 and MOF-808-TA metal-organic framework materials in Example 7

[0053] 1) Study on the C2H2 / CO2 separation performance of the MOF-808 and MOF-808-TA metal-organic framework materials, in the range of 34.17 - 51.26 min g -1 It shows that the separation effect of MOF-808-TA is better than that of MOF-808 in the range of 28.97 - 35.18 min g -1 Better. Figure 4 Penetration curve of the MOF-808 and MOF-808-TA metal-organic framework materials synthesized in the present invention at 298K and 2 mL / min.

[0054] 2) Study on the C2H2 / CO2 separation performance of the MOF-808-TA metal-organic framework material at different temperatures of 288K, 298K, and 308K. When the temperature is 288K, it is reflected in the range of 38.74 - 61.54 min g -1 , when the temperature is 298K, it is reflected in the range of 26.35 - 40.99 min g -1 , when the temperature is 308K, it is reflected in the range of 33.22 - 54.41 min g -1 , and the separation effect is better when the temperature is 288K. Figure 5 Penetration curves of the MOF-808-TA metal-organic framework material synthesized in the present invention at 288K, 298K, and 308K respectively.

[0055] 3) Study on the C2H2 / CO2 separation performance of the MOF-808-TA metal-organic framework material at different flow rates of 2 mL / min, 3 mL / min, and 4 mL / min. When the flow rate is 2 mL / min, it is reflected in the range of 32.97 - 51.26 min g -1 , when the flow rate is 3 mL / min, it is reflected in the range of 15.86 - 22.66 min g -1 , when the flow rate is 4 mL / min, it is reflected in the range of 21.76 - 32.01 min g -1 , and the separation effect is better when the flow rate is 2 mL / min.Figure 6 Penetration curves of the MOF-808-TA metal-organic framework material synthesized according to the present invention at 2 mL / min, 3 mL / min, and 4 mL / min respectively.

[0056] 4) Study on the separation performance of the MOF-808-TA metal-organic framework material for C2H2 / CO2 in dry and humid environments at 298K and 2 mL / min. The dry condition is reflected in 34.17 - 51.26 min g -1 , and the humid condition is reflected in 38.71 - 53.54 min g -1 , and the separation effect is better under dry conditions. Figure 7 Penetration curves of the MOF-808-TA metal-organic framework material synthesized according to the present invention for dry and humid environments at 298K and 2 mL / min respectively.

[0057] 5) Study on the separation performance of three groups of MOF-808-TA metal-organic framework materials synthesized according to the preparation method of Example 2 for C2H2 / CO2 at 298K and 2 mL / min. The separation effects of the three groups of materials are not significantly different. Figure 8 Penetration curves of three groups of MOF-808-TA metal-organic framework materials synthesized according to the present invention at 298K and 2 mL / min.

[0058] Example 8 Study on the specific surface area and pore size of MOF-808 and MOF-808-TA metal-organic framework materials

[0059] 1) According to Figure 9 The changes of the MOF-808 metal-organic framework material at a relative pressure of 0.0822 and the MOF-808-TA metal-organic framework material at a relative pressure of 0.0392 are consistent with the theoretical data of the MOF-808 and MOF-808-TA metal-organic framework materials. Figure 9 Specific surface area diagram of the MOF-808 metal-organic framework material synthesized in Example 1 and the MOF-808-TA metal-organic framework material in Example 2.

[0060] 2) According to Figure 10 The intrinsic viscosity of the MOF-808 metal-organic framework material is 0.8217 dL / g at 0.5709 nm and 3.5815 dL / g at 1.1272 nm, and the intrinsic viscosity of the MOF-808-TA metal-organic framework material is 0.3762 dL / g at 0.5408 nm and 0.4245 dL / g at 0.9611 nm, which is consistent with the theoretical data of the MOF-808 and MOF-808-TA metal-organic framework materials.Figure 10 Pore size distribution diagrams of the MOF-808 metal-organic framework material synthesized in Example 1 and the MOF-808-TA metal-organic framework material in Example 2.

Claims

1. Based on MOF-808-TA metal organic framework material, characterized in that its preparation method comprises the following steps: 1) Preparation of MOF-808-TA: 1.1) Add tartaric acid to water and stir for 10-20 minutes. After fully dissolved, add MOF-808 metal organic framework material and stir for 10-20 minutes to dissolve; 1.2) stirring the mixed solution obtained in step 1.1) at 60-70° C. for 24-26 hours; 1.3) After the reaction, the unreacted tartaric acid was washed away by centrifugation with deionized water for 3-4 times, and then the sample was dried in a drying oven at 90-100°C for 20-24h to obtain a white MOF-808-TA sample; 2) Activation: The MOF-808-TA prepared in step 1) was soaked in acetone for 2-3 days, and then activated in an oven at 60-70° C. for 5-6 hours to obtain activated MOF-808-TA.

2. The MOF-808-TA metal organic framework material according to claim 1, characterized in that: In step 1.1), the amount of tartaric acid added is 0.17-0.21 g, the amount of water used is 10-15 mL, and the amount added based on the MOF-808 metal organic framework material is 0.13-0.17 g.

3. The MOF-808-TA metal organic framework material according to claim 1, characterized in that: The preparation method based on MOF-808 metal organic framework material comprises the following steps: 1) Preparation of MOF-808: 1.1) Add ZrOCl2·8H2O, trimesic acid and DMF into a beaker, stir for 10-20 minutes until fully dissolved, then add formic acid and continue stirring for 20-30 minutes; 1.2) placing the mixed solution obtained in step 1.1) in a reaction vessel and heating it at 110-120° C. for 48-50 hours; 1.3) After the reaction is completed, the obtained white solution is slowly cooled to room temperature; 1.4) Use deionized water, DMF and ethanol to perform centrifugal washing 3-4 times, and then dry the sample in a drying oven at 60-70°C for 20-24h to obtain a white MOF-808 sample; 2) Activation: The MOF-808 prepared in step 1) is soaked in acetone for 2-3 days, and then activated in an oven at 60-70° C. for 5-6 hours to obtain activated MOF-808.

4. The MOF-808-TA metal organic framework material according to claim 3, characterized in that: In step 1.1), the amount of ZrOCl2·8H2O added is 0.253-0.263 g, the amount of trimesic acid added is 0.051-0.061 g, the amount of DMF used is 10-15 mL, and the amount of formic acid used is 12 mL.

5. Application of the MOF-808-TA metal organic framework material according to any one of claims 1 to 4 in C2H2 / CO2 separation.

6. The use according to claim 5, characterized in that: The method is as follows: Take the MOF-808-TA metal organic framework material, separate the mixed gas under dry, 288K, 2mL / min conditions in a mixed gas atmosphere with a C2H2 / CO2 volume ratio of 50:

50.

7. Application of the MOF-808 metal organic framework material according to claim 3 or 4 in C2H2 / CO2 separation.

8. The use according to claim 7, characterized in that: The method is as follows: Take the MOF-808 metal organic framework material, separate the mixed gas under the conditions of 298K and 2mL / min in a mixed gas atmosphere with a C2H2 / CO2 volume ratio of 50:50.

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