CN113667136A

CN113667136A - Ultrahigh-stability and low-cost metal-organic framework material for efficiently separating acetylene/carbon dioxide and preparation method thereof

Info

Publication number: CN113667136A
Application number: CN202111056328.1A
Authority: CN
Inventors: 李斌; 陆风帆; 钱国栋
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2021-09-09
Filing date: 2021-09-09
Publication date: 2021-11-19
Anticipated expiration: 2041-09-09
Also published as: CN113667136B

Abstract

The invention discloses a preparation method of an aluminum-based metal-organic framework (MOFs) material with high stability and application thereof in the field of gas adsorption and separation; the MOFs material can be used as an adsorbent to realize the high-efficiency separation of acetylene/carbon dioxide. The preparation method improves the integral reaction yield and enables the product to have good crystallinity and uniform appearance by regulating and controlling the proportion, reaction time and reaction temperature between reactants and a solvent in the synthesis process. The microporous Al-MOFs material has excellent chemical stability and structural versatility, and the characteristics of low cost and easy large-scale synthesis of aluminum greatly promote the industrial application process of the series of materials in the field of gas adsorption and separation.

Description

Ultrahigh-stability and low-cost metal-organic framework material for efficiently separating acetylene/carbon dioxide and preparation method thereof

Technical Field

The invention relates to the technical field of metal-organic framework nano materials and gas adsorption and separation, in particular to a large-scale preparation method of aluminum-based MOFs materials (Al-MOFs) and application thereof in gas adsorption and separation. The material can be used for high-efficiency separation of acetylene/carbon dioxide, and acetylene is selectively adsorbed from mixed gas so as to achieve the aim of purifying acetylene.

Background

Acetylene, one of the very important industrial gases, can be used as a fuel and for producing other chemicals (such as vinyl chloride, acrylic acid, etc.), and is widely used in the fields of petrochemical industry, electronic industry, etc. At present, acetylene is mainly generated through processes of petroleum fractionation, cracking and the like, and is often accompanied with impurity gases such as carbon dioxide, methane and the like, so that the subsequent use benefit is greatly influenced. Thus, the purification of acetylene is a problem to be solved urgently in industry. The acetylene molecules and the carbon dioxide molecules have very similar boiling points (189.3K and 194.7K) and the same kinetic dimensions

Making acetylene/carbon dioxide separation very challenging. The traditional separation method comprises solvent extraction, cryogenic rectification and the like, but has the defects of high cost and large energy consumption. Compared with the prior art, the adsorption separation technology based on the porous material can realize low-energy-consumption separation of acetylene/carbon dioxide, and is more energy-saving and environment-friendly.

Metal-organic frameworks (MOFs) are solid crystalline porous materials formed by connecting inorganic clusters (or secondary building units, SBUs) and organic molecules through coordination bonds. Compared with traditional porous materials such as molecular sieves and activated carbon, the porous metal-organic framework material has the advantages of high specific surface area and pore volume, precisely adjustable pore channel structure, easy functionalization and the like, and becomes one of ideal adsorbent materials for realizing the efficient separation of mixed gas.

In recent years, research on the separation of acetylene/carbon dioxide by using a metal-organic framework material as an adsorbent has been advanced by using strategies such as introduction of functional sites (e.g., open metal sites), but the method still has the disadvantages of low adsorption amount, poor chemical stability, difficult regeneration, high cost and the like. For example, in practical industrial processes, acetylene feed gas often contains water vapor and other acidic corrosive gasesAnd the like. Therefore, in addition to excellent acetylene/carbon dioxide adsorption and separation performance, the chemical stability of MOFs materials is also very important for their practical industrial applications. In addition, most of the reports for C are now made₂H₂/CO₂The separated MOFs material has high raw material cost, cannot be produced in a large scale and cannot meet the actual industrial application requirement. In conclusion, how to prepare the MOFs material with high separation performance, high stability, low regeneration energy consumption and low cost and realize the high-efficiency separation of acetylene/carbon dioxide is of great significance to the industrial acetylene purification process and is a challenging problem.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides an Al-MOFs material with ultrahigh stability and low synthesis cost and a preparation method thereof, and the preparation method controls the crystal growth process of a product by regulating and controlling the ratio, reaction time and reaction temperature between a reactant and a solvent, so that the product has uniform appearance, and the material with good crystallinity and stability is prepared. The material is used in the field of gas adsorption and separation, and can realize the high-efficiency separation of acetylene/carbon dioxide. The microporous Al-MOFs material synthesized by the method has excellent chemical stability and structural versatility, and the material has great industrial application value of acetylene/carbon dioxide separation due to the low cost of aluminum and organic ligands and the characteristic that Al-MOF is easy to synthesize in a large scale.

The invention adopts the following technical scheme:

an Al-MOFs material, which is a solid crystalline porous material with a one-dimensional network structure, and has a general structural formula of Al (OH) X (wherein X represents a dicarboxylic acid organic ligand); the Al-MOFs material can be used as an adsorbent for high-efficiency separation of acetylene/carbon dioxide.

The organic dicarboxylic acid ligand comprises isophthalic acid (1, 3-H)₂BDC), 5-aminoisophthalic acid (5-amoIPA), 5-hydroxyisophthalic acid (5-hidPA), pyridine-3, 5-dicarboxylic acid (pyd-3,5-BDC), pyridine-2, 4-dicarboxylic acid (pyd-2,4-BDC), pyrazine-2, 6-dicarboxylic acid (pyz-2,6-BDC), pyrimidine-4, 6-dicarboxylic acid (pym-4,6-BDC), 1,3, 5-triazine-2, 4-dicarboxylic acid (1,3,5-trz-2, 4-dicarboxylic acid4-BDC), 2, 5-furandicarboxylic acid (2,5-FDC), 2, 5-thiophenedicarboxylic acid (2,5-TDC), 3, 5-pyrazoledicarboxylic acid (3,5-PyzDC), 2, 4-furandicarboxylic acid (2,4-FDC), 2, 4-thiophenedicarboxylic acid (2,4-TDC), 2, 4-pyrroledicarboxylic acid (2,4-PylDC), 3, 5-isoxazoledicarboxylic acid (3,5-IsxDC), 3, 5-isothiazoledicarboxylic acid (3,5-IstDC) and 2, 5-pyrroledicarboxylic acid (2, 5-PylDC).

The preparation method comprises the following steps:

1) mixing organic ligands of the dicarboxylic acid, a regulator and a solvent in proportion, carrying out ultrasonic treatment until a clear solution is obtained, adding a certain amount of soluble metal salt or metal salt solution into the solution, carrying out ultrasonic treatment until a uniform turbid solution is obtained, and then carrying out reaction by using an oven or a magnetic stirrer.

2) And after the reaction is finished, performing suction filtration, washing the mixture for three times by using one of deionized water, N-dimethylformamide and acetonitrile during suction filtration, then washing the mixture for three times by using one of anhydrous methanol, acetone, anhydrous ethanol and dichloromethane, and drying to obtain the Al-MOFs material.

In the above technical scheme, the organic ligand is isophthalic acid (1, 3-H)₂BDC), 5-aminoisophthalic acid (5-amoIPA), 5-hydroxyisophthalic acid (5-hidPA), pyridine-3, 5-dicarboxylic acid (pyd-3,5-BDC), pyridine-2, 4-dicarboxylic acid (pyd-2,4-BDC), pyrazine-2, 6-dicarboxylic acid (pyz-2,6-BDC), pyrimidine-4, 6-dicarboxylic acid (pym-4,6-BDC), 1,3, 5-triazine-2, 4-dicarboxylic acid (1,3,5-trz-2,4-BDC), 2, 5-furandicarboxylic acid (2,5-FDC), 2, 5-thiophenedicarboxylic acid (2,5-TDC), 3, 5-pyrazoledicarboxylic acid (3,5-PyzDC), 2, 4-Furanedicarboxylic acid (2,4-FDC), 2, 4-thiophenedicarboxylic acid (2,4-TDC), 2, 4-pyrroledicarboxylic acid (2,4-PylDC), 3, 5-isoxazoledicarboxylic acid (3,5-IsxDC), 3, 5-isothiazoledicarboxylic acid (3,5-IstDC) and 2, 5-pyrroledicarboxylic acid (2, 5-PylDC).

The soluble metal salt is a soluble aluminum salt;

the modifier comprises one or more of formic acid, acetic acid, trifluoroacetic acid, hydrochloric acid, hydrofluoric acid, sodium hydroxide and potassium hydroxide, the modifier is reasonably selected according to the properties of the dicarboxylic acid ligand, the integral structure of the dicarboxylic acid ligand is not broken while the dicarboxylic acid ligand is deprotonated, the meta-aromatic ring dicarboxylic acid organic ligand is generally adjusted by using acid, and the five-membered heterocyclic dicarboxylic acid organic ligand is generally adjusted by using alkali;

the solvent comprises one or more of deionized water, ethanol, methanol, acetonitrile, N-dimethylformamide, N-dimethylacetamide, N-diethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide;

the ultrasonic temperature is 25-50 ℃, and the ultrasonic time is 5-120 min;

the reaction temperature of the oven is 85-150 ℃; the reaction time of the oven is 12-96 hours;

the stirring temperature of the magnetic stirrer is 85-150 ℃; the stirring speed of the stirrer is 200-500 rpm; the reaction time of the stirrer is 4-96 h;

the soluble aluminum salt comprises one or more of aluminum chloride, aluminum sulfate, basic aluminum acetate, aluminum nitrate and sodium metaaluminate;

during the suction filtration, washing with one of deionized water, N-dimethylformamide and acetonitrile for three times, and then washing with one of anhydrous methanol, acetone, anhydrous ethanol and dichloromethane for three times;

the drying treatment needs to adopt a solvent exchange method to exchange the homogeneous phase crystal material obtained after the suction filtration with one of high-purity methanol, high-purity ethanol and high-purity acetone (the high-purity concentration is more than or equal to 99.8%) for multiple times, wherein the interval is at least 3h each time, and then the homogeneous phase crystal material is sequentially subjected to vacuum drying for 12h at room temperature and 50-120 ℃ respectively to obtain the Al-MOFs material capable of being used for acetylene/carbon dioxide separation.

The molar ratio of the meta-aromatic dicarboxylic acid organic ligand to the metal salt is 1 (1-3); the ratio of the organic ligand to the regulator to the solvent is 1mmol (0-25 mL) to 3-30 mL), and the related reagents are all commercial analytical pure reagents and are not further purified before use.

The MOFs material prepared by the simple and rapid method comprises the following steps: the microporous Al-MOFs has the characteristics of good chemical stability, structural function adjustability, low synthesis cost and easiness in large-scale synthesis, so that the industrial application potential of the series of materials is far better than that of similar MOFs materials. The constructed Al-MOFs material has a proper pore structure, so that the acetylene/carbon dioxide is efficiently separated.

The invention principle of the invention is as follows:

the invention designs and synthesizes a series of Al-MOFs materials according to the current difficulty of the acetylene purification problem which is very important industrially, and the selected organic ligand is a meta-aromatic ring dicarboxylic acid organic ligand. Such as CAU-10-H synthesized using 1, 3-phthalic acid and aluminum sulfate octadecahydrate, has a size slightly larger than the kinetics of acetylene and carbon dioxide

Is/are as follows

The structure can ensure that acetylene molecules are effectively accumulated in the pore channel to form an acetylene molecule cluster, thereby increasing the total adsorption amount of materials to acetylene and achieving the purpose of efficiently separating acetylene/carbon dioxide, and a CAU-10-H packed column bed is used for realizing the total pressure of 298K and 1bar and the total pressure of 2mL min^-1C at Total flow₂H₂/CO ₂50/50 in the experiment of mixed gas, the acetylene adsorption amount of CAU-10-H is up to 3.3mmol g^-1The acetylene/carbon dioxide separation ratio is 3.4, which is one of the most excellent materials known at present. Based on the success of the CAU-10-H material in the acetylene/carbon dioxide separation field, the range is expanded to the other organic ligands of meta-aromatic ring dicarboxylic acid and five-membered heterocyclic dicarboxylic acid. Compared with the rest high-performance acetylene/carbon dioxide separation MOFs materials, the Al-MOFs materials show ultrahigh chemical stability, and can still maintain the structural stability after being soaked in water, acidic and alkaline solutions. Excellent C₂H₂/CO₂The combination of the separation performance, the ultrahigh chemical stability and the low synthesis cost means that the series of Al-MOFs materials are C which has the most industrial utilization value so far₂H₂/CO₂One of the materials is separated.

The invention has the beneficial effects that:

(1) An Al-MOFs material, which is a solid crystalline porous material with a one-dimensional network structure, and has a general structural formula of Al (OH) X (wherein X represents a dicarboxylic acid organic ligand); the series of materials have proper one-dimensional pore channels and functional surfaces, and can ensure that acetylene molecules form acetylene molecule clusters in the pore channels, thereby increasing the total adsorption amount of the materials on acetylene and achieving C₂H₂/CO₂The purpose of high-efficiency separation is achieved; the preparation method can improve the integral reaction yield and ensure that the product has good crystallinity and uniform appearance by regulating and controlling the proportion, reaction time and reaction temperature between reactants and a solvent in the synthesis process.

(2) The series of Al-MOFs materials can be used as an adsorbent for high-efficiency separation of acetylene/carbon dioxide. At 298K, 1bar total pressure and 2mL min^-1C at Total flow₂H₂/CO ₂50/50 experiment of mixed gas, the acetylene adsorption quantity of the Al-MOFs material>3.0mmol g^-1Acetylene/carbon dioxide separation ratio>3.0, the comprehensive performance is in front of the commercial porous materials and the reported similar materials.

(3) The series of materials have good chemical stability, can still maintain the structural stability after being soaked in water for 72 hours and soaked in a solution with the pH value of 1, 2,4, 10 and 12, and provides a powerful and reliable guarantee for the practical application of the materials in industrial environment.

(4) The material has good thermal stability. The structure remained unchanged over the 300 ℃ temperature range tested.

The series of Al-MOFs materials combine a plurality of advantages of ultrahigh stability, low synthesis cost, easiness in large-scale production and the like, greatly meet various requirements on acetylene purification and adsorption materials under the industrial background, and greatly promote the industrial application process of the MOFs materials in the field of gas adsorption and separation. The invention provides a new idea for improving the acetylene/carbon dioxide separation performance of the porous material, also provides different visual angles for developing new MOFs material with high separation performance, high stability and low cost, and is beneficial to promoting the industrial application of the MOFs material in the separation of other important gases in the long run.

Drawings

FIG. 1 is a schematic diagram of the organic ligands involved in the present invention (FIG. 1a) and used in the materials of example 1 (FIG. 1b), example 2 (FIG. 1c) and example 3 (FIG. 1 d).

FIG. 2 is a schematic representation of the microcrystalline structure of the material of example 1.

FIG. 3 is a PXRD pattern of the material of example 1.

FIG. 4 is the 77K nitrogen isothermal total adsorption curve (FIG. 4a) and pore size distribution plot (FIG. 4b) for the material of example 1.

FIG. 5 shows PXRD pattern and acetylene isothermal adsorption curve (296K) before and after testing for water stability and chemical stability of the material of example 1.

FIG. 6 is a PXRD pattern after thermal stability testing of the material of example 1.

FIG. 7 is a single component isothermal adsorption curve (296K) for acetylene and carbon dioxide for the material of example 1.

FIG. 8 is 296K equimolar C predicted by IAST theory in example 1₂H₂/CO₂Two-component mixed gas competes for the adsorption curve.

FIG. 9 shows a material pair C in example 1₂H₂/CO₂(50/50, v/v) and C₂H₂/CO₂(2/1, v/v) IAST separation Selectivity of two ratios of mixed gases (296K).

FIG. 10 shows the results of the column packed with the material of example 1 at 298K, 1bar total pressure and 2mL min^-1C at Total flow₂H₂/CO ₂50/50 dynamic breakthrough experiment test curves.

FIG. 11 is a PXRD pattern for the synthesis and product of the material scale-up in example 1.

FIG. 12 is a schematic representation of the microcrystalline structure of the material of example 2.

FIG. 13 is a PXRD pattern of the material in example 2.

FIG. 14 is a 77K nitrogen isothermal total adsorption curve and pore size distribution plot for the material of example 2.

FIG. 15 is a single component isothermal adsorption curve (296K) for acetylene and carbon dioxide for the material of example 2.

FIG. 16 shows the material pair C in example 2₂H₂/CO₂(50/50, v/v) IAST separation Selectivity of the mixed gas (296K).

FIG. 17 is a PXRD pattern of the material in example 3.

FIG. 18 is a 77K nitrogen isothermal total adsorption curve for the material of example 3.

FIG. 19 is a single component isothermal adsorption curve (296K) for acetylene and carbon dioxide for the material of example 3.

FIG. 20 shows the material pair C in example 3₂H₂/CO₂(50/50, v/v) IAST separation Selectivity of the mixed gas (296K).

Detailed Description

The present invention will be further explained with reference to examples, which do not limit the scope of the present invention, and various modifications and variations can be made by those skilled in the art without inventive changes based on the technical solution of the present invention.

Example 1

1.2mmol (200mg) of the organic ligand isophthalic acid was dissolved in 1mL DMF solvent and sonicated to give a clear solution, 1.2mmol (800mg) of the metal salt Al₂(SO₄)₃·18H₂O was dissolved in 4mL of deionized water. Then the aqueous solution of metal salt is dropped into the DMF solution of isophthalic acid under stirring, the clear solution quickly becomes white paste, after a period of ultrasonic treatment, it is transferred to a hydrothermal kettle to react for 24h under the condition of 135 ℃. Subsequently, it was slowly cooled to room temperature in air. And respectively washing with DMF and deionized water for 3 times during suction filtration to obtain pure CAU-10-H.

The microscopic crystal structure of the material is schematically shown in fig. 2, and the PXRD characterization data is shown in fig. 3. And exchanging the obtained homogeneous phase crystal material in anhydrous methanol for multiple times by adopting a solvent exchange method, wherein the interval is at least 3 hours each time, and then sequentially drying the homogeneous phase crystal material in vacuum at room temperature and 50 ℃ for 12 hours respectively to obtain the purified CAU-10-H.

To test the specific surface area of CAU-10-H, an isothermal nitrogen soak at 77K was performedThe test results are shown in FIG. 4, with a BET specific surface area of 627m²Per g, pore diameter of

In order to test the water stability and chemical stability of CAU-10-H, after immersing the synthesized fresh sample in water for 72H and in acid-base solution with

pH

1 and 12 for 72H, PXRD data and acetylene adsorption curve of the sample are measured (fig. 5), and it can be seen from the figure that the material still maintains good structural integrity, indicating that it has excellent water stability and acid-base stability.

To characterize the thermal stability of CAU-10-H in air environment, the samples were heated to 50 deg.C, 100 deg.C, 150 deg.C, 200 deg.C, 250 deg.C, 300 deg.C and held for 12H, respectively, before PXRD characterization. As can be seen from the PXRD pattern, the sample can still keep good crystal structure integrity under the environment of 300 ℃ (FIG. 6).

In order to characterize the single-component adsorption performance of CAU-10-H to acetylene and carbon dioxide at normal temperature, C at the temperature of 296K is tested₂H₂And CO₂The single-component adsorption curve of (FIG. 7) shows that CAU-10-H shows good C₂H₂/CO₂And 4, selective separation prospect.

To further CAU-10-H pair C₂H₂/CO₂The selective adsorption separation effect of the mixed gas is evaluated, and the equimolar C is predicted by Ideal Adsorption Solution Theory (IAST)₂H₂/CO₂The two-component mixed gas competitive adsorption curve (FIG. 8) shows that CAU-10-H exhibits preferential adsorption of acetylene.

To evaluate CAU-10-H to C more intuitively₂H₂/CO₂The adsorption separation effect of the mixed gas is calculated, and the adsorption separation effect is calculated for C at 296K₂H₂/CO₂(50/50, v/v) IAST separation selectivity of gas mixture (FIG. 9), it can be seen that CAU-10-H has good acetylene/carbon dioxide separation performance, and is one of the most excellent materials known at present.

To simulate a practical industrial separation process, dynamic breakthrough experiments were used to evaluate CAU-10-H versus C₂H₂/CO₂Actual separation effect of the mixed gas. 0.8563g of the activated sample was packed into a packed column as a fixed bed of an adsorption column, followed by 2mL min^-1 Flow rate introduction 50/50C₂H₂/CO₂The gas mixture was subjected to breakthrough testing (FIG. 10). As can be seen from the figure, CAU-10-H can realize pair 50/50C₂H₂/CO₂And (3) high-efficiency separation of the mixed gas.

To demonstrate the feasibility of scale-up synthesis of this series of materials, the scale-up of CAU-10-H was expanded and PXRD characterization was performed on the product (FIG. 11). As can be seen from the figure, the product synthesized on a scale has good crystallinity.

Example 2

Dissolving 1.2mmol 2, 5-thiophenedicarboxylic acid in 5mL 0.4mmol/mL NaOH aqueous solution, sonicating to obtain a clear solution, and adding 0.9mmol of the metal salt AlCl₃·6H₂O and 0.3mmol of NaAlO₂After ultrasonic treatment for a period of time, the solution is transferred to a hydrothermal kettle and reacted for 24 hours at the temperature of 100 ℃. Subsequently, it was slowly cooled to room temperature in air. And respectively washing with DMF and absolute ethyl alcohol for 3 times during suction filtration to obtain Al (OH) (TDC).

The microscopic crystal structure of the material is schematically shown in fig. 12, and the PXRD characterization data is shown in fig. 13. The obtained homogeneous phase crystal material is exchanged in absolute methanol for a plurality of times by a solvent exchange method, each time at least 3 hours, and then is dried in vacuum for 12 hours at room temperature and 50 ℃ in sequence to obtain purified Al (OH) (TDC).

To test the specific surface area and pore size distribution of Al (OH) (TDC), a 77K nitrogen isothermal adsorption test was performed, the test results are shown in FIG. 14, and the BET specific surface area is 1221m²Per g, pore diameter of

In order to characterize the single-component adsorption performance of Al (OH) (TDC) on acetylene and carbon dioxide at normal temperature, C at the temperature of 296K is tested₂H₂And CO₂Single component adsorption ofThe curve (FIG. 15) shows that Al (OH) (TDC) has good C₂H₂/CO₂The separability was selected.

In order to more intuitively show Al (OH) (TDC) vs C₂H₂/CO₂The adsorption separation effect of the mixed gas is calculated, and the adsorption separation effect is calculated for C at 296K₂H₂/CO₂(50/50, v/v) IAST separation selectivity of gas mixture (FIG. 16), it can be seen that Al (OH) (TDC) has a promising application for efficient acetylene/carbon dioxide separation.

Example 3

Dissolving 1.0mmol of organic ligand 3, 5-pyrazole dicarboxylic acid in 5mL of 0.4mmol/mL NaOH aqueous solution, performing ultrasonic treatment to obtain clear solution, and adding 1.2mmol of metal salt AlCl₃·6H₂O was dissolved in 4mL of deionized water. Then, the aqueous solution of the metal salt is dripped into the NaOH aqueous solution of the 3, 5-pyrazole dicarboxylic acid under stirring, after ultrasonic treatment for a period of time, the solution is transferred into a hydrothermal kettle to react for 24 hours at the temperature of 100 ℃. Subsequently, it was slowly cooled to room temperature in air. The filtration is carried out by washing with DMF and absolute methanol for 3 times respectively to obtain pure Al (OH) (PyzDC).

PXRD characterization data for the material are shown in figure 17. The obtained homogeneous phase crystal material is exchanged in absolute methanol for a plurality of times by a solvent exchange method, each time at least 3 hours, and then is dried in vacuum for 12 hours at room temperature and 50 ℃ in sequence to obtain purified Al (OH) (PyzDC).

To test the specific surface area of Al (OH) (PyzDC), a 77K nitrogen isothermal adsorption test was performed, and the test results are shown in FIG. 18, where the BET specific surface area is comparable to that of Al (OH) (TDC).

To characterize the single-component adsorption properties of Al (OH) (PyzDC) to acetylene and carbon dioxide at room temperature, C at a temperature of 296K was tested₂H₂And CO₂As can be seen from the single-component adsorption curve (FIG. 19), Al (OH) (PyzDC) adsorbs acetylene first, and has a promising application prospect in acetylene/carbon dioxide separation.

For clarity of presentation of Al (OH) (PyzDC) vs. C₂H₂/CO₂The adsorption separation effect of the mixed gas is calculated, and the adsorption separation effect is calculated for C at 296K₂H₂/CO₂(50/50, v/v) IAST separation selectivity of the gas mixture (FIG. 20), it is clear that Al (OH) (PyzDC) has excellent acetylene/carbon dioxide separation performance.

Claims

1. An Al-MOFs material is characterized in that the material is a framework material with a one-dimensional network structure, and the structural general formula is Al (OH) X, wherein X represents a dicarboxylic acid organic ligand; the Al-MOFs material can be used as an adsorbent for high-efficiency separation of acetylene/carbon dioxide.

2. The Al-MOFs material of claim 1, wherein the dicarboxylic acid organic ligand is a meta-aromatic ring dicarboxylic acid organic ligand or a five-membered heterocyclic dicarboxylic acid organic ligand.

3. The Al-MOFs material according to claim 1, wherein the one-dimensional channel size is between

In the meantime.

4. Al-MOFs material according to claim 1, wherein the properties are such that at 298K, 1bar total pressure and 2mL min^-1C at Total flow₂H₂/CO₂50/50 experiment of mixed gas, the acetylene adsorption quantity of the Al-MOFs material>3.0mmol g^-1Acetylene/carbon dioxide separation ratio>3.0。

5. The preparation method of the Al-MOFs material is characterized by comprising the following steps: 1) mixing organic ligands of the dicarboxylic acid, a regulator and a solvent in proportion, carrying out ultrasonic treatment to obtain a clear solution, adding soluble metal salt or metal salt solution into the solution, carrying out ultrasonic treatment to obtain a uniform turbid solution, then carrying out reaction by using an oven or a magnetic stirrer, carrying out suction filtration after the reaction is finished, and carrying out drying treatment to obtain the Al-MOFs material.

6. The method for preparing Al-MOFs materials according to claim 5, wherein said dicarboxylic acid organic ligand is an aromatic-isophthalic acid organic ligand and a five-membered heterocyclic dicarboxylic acid organic ligand, and comprises isophthalic acid, 5-aminoisophthalic acid, 5-hydroxyisophthalic acid, pyridine-3, 5-dicarboxylic acid, pyridine-2, 4-dicarboxylic acid, pyrazine-2, 6-dicarboxylic acid, pyrimidine-4, 6-dicarboxylic acid, 1,3, 5-triazine-2, 4-dicarboxylic acid, 2, 5-furandicarboxylic acid, 2, 5-thiophenedicarboxylic acid, 3, 5-pyrazoledicarboxylic acid, 2, 4-furandicarboxylic acid, 2, 4-thiophenedicarboxylic acid, 2, 4-pyrroledicarboxylic acid, 3, 5-isoxazoledicarboxylic acid, 2, 4-thiophenedicarboxylic acid, 5-thiophenedicarboxylic acid, and the like, 3, 5-isothiazoledicarboxylic acid and 2, 5-pyrroledicarboxylic acid;

the soluble metal salt is a soluble aluminum salt;

the modifier comprises one or more of formic acid, acetic acid, trifluoroacetic acid, hydrochloric acid, hydrofluoric acid, sodium hydroxide and potassium hydroxide, the use of the modifier needs to be reasonably selected according to the properties of a dicarboxylic acid ligand, the integral structure of the dicarboxylic acid ligand is not broken while the dicarboxylic acid ligand is deprotonated, the meta-aromatic ring dicarboxylic acid organic ligand is adjusted by using acid, and the five-membered heterocyclic dicarboxylic acid organic ligand is adjusted by using alkali;

the solvent comprises one or more of deionized water, ethanol, methanol, acetonitrile, N-dimethylformamide, N-dimethylacetamide, N-diethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

7. The method for preparing the Al-MOFs materials according to claim 5, wherein the ultrasonic temperature is 25-50 ℃ and the ultrasonic time is 5-120 min;

and the drying treatment needs to adopt a solvent exchange method to exchange the homogeneous phase crystal material obtained after the suction filtration with one of high-purity methanol, high-purity ethanol and high-purity acetone for multiple times, wherein the interval is at least 3 hours each time, and then the homogeneous phase crystal material is sequentially dried in vacuum for 12 hours at room temperature and 50-120 ℃ respectively to obtain the dried MOFs material.

8. The preparation method of the Al-MOFs materials according to claim 5, wherein the molar ratio of the organic dicarboxylic acid ligand to the metal salt is 1 (1-3); the ratio of the organic ligand of the dicarboxylic acid, the regulator and the solvent is 1mmol (0-25 mL) to (3-30 mL), and the regulator and the solvent are all commercial analytical reagents.