Covalent organic framework material for directly capturing carbon dioxide in air and coupling solar energy photo-thermal rapid desorption and preparation method of covalent organic framework material

Abstract

The invention discloses a covalent organic framework material for directly capturing carbon dioxide in air and coupling solar photo-thermal rapid desorption and a preparation method of the covalent organic framework material, and belongs to the field of materials. According to the material, piperazine with secondary amine sites and dialdehyde derivatives are used as raw materials, dioxane and mesitylene, m-xylene and mesitylene or o-xylene and mesitylene are used as solvents, and solvothermal reaction is performed; and after the reaction is finished, sequentially carrying out suction filtration and washing by using DMF and THF, carrying out Soxhlet extraction for 24 hours, and then carrying out vacuum drying to obtain the covalent organic framework. The aldehyde and the secondary amine are condensed according to the proportion of 1: 2, and the secondary amine site of the raw material piperazine is converted into the tertiary amine site in the covalent organic framework through aminal reaction. Tertiary amine nitrogen atoms can specifically recognize carbon dioxide in air and perform chemical adsorption, and firm covalent bonds can ensure the stability of a covalent organic framework, so that efficient air carbon dioxide capture is realized. In addition, ionic bonds formed by the covalent organic framework and carbon dioxide are also beneficial to coupling solar photo-thermal low-energy-consumption desorption.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of air carbon dioxide capture and covalent organic framework materials, and particularly relates to a covalent organic framework material for direct air carbon dioxide capture and coupling solar light heat rapid desorption and a preparation method thereof. BACKGROUND

[0002] In the past half century, the extensive use of fossil energy has brought about serious environmental problems. The greenhouse effect caused by excessive emission of carbon dioxide is threatening the sustainable development of human society. With the intensification of global warming, in order to combat the increasingly serious ecological changes, a low-cost, large-scale popularization technology for reducing carbon dioxide concentration is urgently needed. Direct air capture technology (DAC) is an innovative climate solution that can directly capture carbon dioxide from the air and store it, thereby reducing the concentration of greenhouse gases in the atmosphere. This technology plays an increasingly important role in addressing the challenges of global warming.

[0003] The core of DAC technology lies in the carbon dioxide adsorbent. Traditional adsorbents such as liquid solvents and amine-based compounds achieve specific adsorption by forming strong covalent bonds with carbon dioxide in the air through chemical reactions, and then desorption is completed at high temperature to complete the cycle. However, these traditional adsorbents have problems such as poor stability and difficult desorption, which brings additional costs in practical application. SUMMARY

[0004] Traditional carbon dioxide adsorbents have problems such as cycle performance degradation and high desorption energy consumption. As a new type of efficient air carbon capture material, covalent organic framework should have excellent stability and abundant adsorption sites. Covalent organic framework (COF) is a kind of porous material formed by connecting light elements through dynamic covalent bonds, which has extremely high porosity and excellent thermal stability. At the same time, covalent organic framework with tertiary amine sites can convert carbon dioxide into bicarbonate, and then combine it with protonated nitrogen atoms on the COF skeleton through electrostatic interaction. This not only realizes the specific recognition and capture of carbon dioxide in the air, but also reduces the difficulty of carbon dioxide desorption through electrostatic interaction. This covalent organic framework with secondary amine sites has great application potential in the field of air carbon capture.

[0005] The aminal is introduced in the synthesis of the COF, so as to reduce the energy consumption of carbon dioxide desorption; thanks to the firm covalent bond, the COF has excellent cycle stability, and the high crystallinity also brings high porosity to the COF. The purpose of the present application is to provide a covalent organic framework material for direct air carbon dioxide capture and coupling solar light heat rapid desorption and a preparation method thereof, which is based on the construction of a covalent organic framework with a tertiary amine site by using a piperazine with a secondary amine site and a dithio derivative as a construction block, so as to obtain the covalent organic framework material for carbon dioxide capture in air through a solvothermal reaction.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows: A covalent organic framework material for direct air carbon dioxide capture and coupling solar light heat rapid desorption, the material structure formula is as follows: 、 or wherein R is CH3, OH, F, Cl, Br or I.

[0007] The second object of the present application is to provide a preparation method of a covalent organic framework material for direct air carbon dioxide capture and coupling solar light heat rapid desorption, the preparation method comprising the following steps: The piperazine with a secondary amine site and a dithio derivative are used as raw materials and dissolved in a reaction solvent, and the reaction is carried out at 100-130 DEG C for 3-7 days; The piperazine with a secondary amine site has the following structure: The dithio derivative has the following structure: 、 、 、 、 、 、 、 、 or .

[0008] In an embodiment, the amount-of-substance ratio of the piperazine with a secondary amine site to the dithio derivative is 1:3-3:1.

[0009] In an embodiment, the reaction solvent is a mixture of dioxane and mesitylene, a mixture of m-xylene and mesitylene, or a mixture of o-xylene and mesitylene.

[0010] In one embodiment, the volume ratio of dioxane to mesitylene, m-xylene to mesitylene, or o-xylene to mesitylene is 1:9 to 9:1.

[0011] In one embodiment, after the reaction is complete, the mixture is naturally cooled to room temperature and the solid powder is collected by filtration, then washed, purified, and dried with an organic solvent.

[0012] In one embodiment, the organic solvent includes one or more of N,N-dimethylformamide and tetrahydrofuran; the purification method includes Soxhlet extraction; and the drying conditions are vacuum, 90-120°C. o C.

[0013] Beneficial effects This invention rationally designs a covalent organic framework material for direct capture of airborne carbon dioxide and coupled with rapid solar photothermal desorption. By reacting piperazine with secondary amine sites with dialdehyde derivatives, a covalent organic framework material with abundant tertiary amine sites is obtained. The tertiary amine sites of the covalent organic framework can chemically react with carbon dioxide and water vapor in the air to form chemical bonds, protonating the nitrogen atoms of the tertiary amine, and converting carbon dioxide into bicarbonate ions, thereby achieving the goal of specifically recognizing and rapidly capturing airborne carbon dioxide. Furthermore, since the chemical bonds formed between the tertiary amine sites of the covalent organic framework and carbon dioxide are low-energy ionic bonds, rapid desorption can be achieved by coupling with solar photothermal energy. As a porous material, the high specific surface area and high porosity of the covalent organic framework can effectively accelerate the mass transfer process of carbon dioxide, improving the efficiency of airborne carbon dioxide capture and desorption cycles. The high stability of the covalent organic framework ensures its continuous operation over long periods, effectively reducing the cost of adsorbent replacement. This invention has the advantages of rapid and efficient airborne carbon dioxide capture, low desorption energy consumption, and low cost. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the synthesis route of a covalent organic framework material for direct air carbon dioxide capture and coupled solar photothermal rapid desorption, as provided in Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the synthesis route of a covalent organic framework material for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption, provided in Embodiment 2 of the present invention. Figure 3 This is a schematic diagram of the synthesis route of a covalent organic framework material for direct air carbon dioxide capture and coupled solar photothermal rapid desorption, provided in Embodiment 3 of the present invention. Figure 4This is a schematic diagram of the synthesis route of a covalent organic framework material for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption, provided in Embodiment 4 of the present invention. Figure 5 This is a schematic diagram of a covalent organic framework material for direct air carbon dioxide capture and coupled solar photothermal desorption, provided in Embodiment 5 of the present invention. Figure 6 A flowchart illustrating the process of capturing carbon dioxide from the air and coupling it with solar photothermal desorption using a covalent organic framework material for direct air carbon dioxide capture and rapid solar photothermal desorption. Figure 7 This is a conceptual diagram of a covalent organic framework material for direct air carbon dioxide capture and coupled solar photothermal desorption. Detailed Implementation

[0015] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0016] Example 1 The preparation method of the covalent organic framework material used for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption in this embodiment is as follows: (1) 0.04 mmol of piperazine building blocks and 0.02 mmol of dialdehyde building blocks (see schematic diagram of synthesis) Figure 1 Add it to a mixture of 0.5 mL trimethylbenzene and 0.5 mL dioxane as a reaction solvent, and disperse it evenly by ultrasonication.

[0017] (2) After ultrasonic dispersion, the mixed solution is transferred to a Shrek tube.

[0018] (3) Place the Shrek tube at 120 o The mixture was kept at a constant temperature of C for 3 days. After the reaction was completed, it was naturally cooled to room temperature and then filtered to collect the solid powder.

[0019] (4) The collected solid powder was washed by centrifugation with DMF and THF for 10 mL × 5 times in sequence, and the solid powder was collected again.

[0020] (5) After Soxhlet extraction of the solid powder with THF as solvent for 24 hours, it was then subjected to a process at 120°C. o The target product, namely the covalent organic framework material for capturing carbon dioxide from the air, was obtained by vacuum drying at C for 12 hours.

[0021] Example 2 The preparation method of the covalent organic framework material used for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption in this embodiment is as follows: (1) 0.04 mmol of piperazine building blocks and 0.02 mmol of dialdehyde building blocks (see schematic diagram of synthesis) Figure 2 (R=CH3) was added to a mixture of 0.5 mL of mesitylene and 0.5 mL of dioxane as a reaction solvent and ultrasonically dispersed until uniform.

[0022] (2) After ultrasonic dispersion, the mixed solution is transferred to a Shrek tube.

[0023] (3) Place the Shrek tube at 120 o The mixture was kept at a constant temperature of C for 3 days. After the reaction was completed, it was naturally cooled to room temperature and then filtered to collect the solid powder.

[0024] (4) The collected solid powder was washed by centrifugation with DMF and THF for 10 mL × 5 times in sequence, and the solid powder was collected again.

[0025] (5) After Soxhlet extraction of the solid powder with THF as solvent for 24 hours, it was then subjected to a process at 120°C. o The target product, namely the covalent organic framework material for capturing carbon dioxide from the air, was obtained by vacuum drying at C for 12 hours.

[0026] Example 3 The preparation method of the covalent organic framework material used for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption in this embodiment is as follows: (1) 0.04 mmol of piperazine building blocks and 0.02 mmol of dialdehyde building blocks (see schematic diagram of synthesis) Figure 3 Add it to a mixture of 0.5 mL trimethylbenzene and 0.5 mL dioxane as a reaction solvent, and disperse it evenly by ultrasonication.

[0027] (2) After ultrasonic dispersion, the mixed solution is transferred to a Shrek tube.

[0028] (3) Place the Shrek tube at 120 o The mixture was kept at a constant temperature of C for 3 days. After the reaction was completed, it was naturally cooled to room temperature and then filtered to collect the solid powder.

[0029] (4) The collected solid powder was washed by centrifugation with DMF and THF for 10 mL × 5 times in sequence, and the solid powder was collected again.

[0030] (5) After Soxhlet extraction of the solid powder with THF as solvent for 24 hours, it was then subjected to a process at 120°C. o The target product, namely the covalent organic framework material for capturing carbon dioxide from the air, was obtained by vacuum drying at C for 12 hours.

[0031] Example 4 The preparation method of the covalent organic framework material used for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption in this embodiment is as follows: (1) 0.04 mmol of piperazine building blocks and 0.02 mmol of dialdehyde building blocks (see schematic diagram of synthesis) Figure 4 (R=CH3) was added to a mixture of 0.5 mL of mesitylene and 0.5 mL of dioxane as a reaction solvent and ultrasonically dispersed until uniform.

[0032] (2) After ultrasonic dispersion, the mixed solution is transferred to a Shrek tube.

[0033] (3) Place the Shrek tube at 120 o The mixture was kept at a constant temperature of C for 3 days. After the reaction was completed, it was naturally cooled to room temperature and then filtered to collect the solid powder.

[0034] (4) The collected solid powder was washed by centrifugation with DMF and THF for 10 mL × 5 times in sequence, and the solid powder was collected again.

[0035] (5) After Soxhlet extraction of the solid powder with THF as solvent for 24 hours, it was then subjected to a process at 120°C. o The target product, namely the covalent organic framework material for capturing carbon dioxide from the air, was obtained by vacuum drying at C for 12 hours.

[0036] Example 5: Direct Capture of Carbon Dioxide from Air This embodiment utilizes a covalent organic framework material for direct air carbon dioxide capture and coupled solar photothermal desorption (see schematic diagram). Figure 5 As shown, the operation flowchart is as follows: Figure 6 (as shown) (1) Approximately 100 mg of the COF sample prepared in Example 1 was loaded into a jacketed column. First, the oil bath was heated to 100°C. o C, to make the column wall temperature 95 o C, the temperature at the center of the column is 60. o C.

[0037] (2) Next, N2 is introduced into the jacketed column and allowed to flow through the sample to activate and expel CO2 from the jacketed column and the sample until the outlet concentration in the jacketed column is less than 5 ppm.

[0038] (3) Cool the oil bath and maintain it at 25°C. oC. The sample is exposed to a gas mixture simulating air conditions, which has the desired air CO2 concentration (400 ppm) and is balanced with air of different relative humidities (20%, 30%, 40%, 50%, 60%, 70%, or 80%). The COF sample adsorbs CO2 until the outlet CO2 concentration is constant, at which point the adsorption is complete.

[0039] (4) The specific CO2 adsorption capacity of the sample was obtained by the difference between the apparent adsorption capacity and the background adsorption capacity per unit mass of sample, which were 0.21, 0.38, 0.42, 0.57, 0.63, 0.62, and 0.64 mmol g at different humidity levels. -1 .

[0040] (5) Place the COF solid powder that has adsorbed carbon dioxide into a transparent quartz beaker, seal the quartz beaker and place it on an open, flat surface, allowing sunlight to irradiate the quartz beaker. After the sunlight has been irradiated for half an hour, water droplets will appear on the wall of the quartz beaker, indicating that desorption is complete. Extract the carbon dioxide from the quartz beaker and collect it.

[0041] like Figure 7 As shown, covalent organic framework materials react with carbon dioxide in the air through tertiary amine nitrogen sites to form low-energy ionic bonds. After capture, the covalent organic framework can undergo a rapid reverse reaction under solar irradiation, achieving high-efficiency air carbon capture.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A covalent organic framework material for direct air carbon dioxide capture and coupled rapid solar photothermal desorption, characterized in that, The structural formula of the material is: 、 or Where R is CH3, OH, F, Cl, Br or I.

2. The method for preparing a covalent organic framework material for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption as described in claim 1, characterized in that, The preparation method includes the following steps: Piperazine and dialdehyde derivatives with secondary amine sites are dissolved in a reaction solvent at 100-130 °C. o At temperature C, the reaction time is 3-7 days; The piperazine with the secondary amine site has the following structure: The structure of the dialdehyde derivative is as follows: 、 、 、 、 、 , , , or .

3. The method for preparing a covalent organic framework material for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption according to claim 2, characterized in that, The molar ratio of the piperazine with the secondary amine site to the dialdehyde derivative is 1:3 to 3:

1.

4. A covalent organic framework material for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption, as described in claim 2, and its preparation method thereof, characterized in that, The reaction solvent is a mixture of dioxane and mesitylene, a mixture of m-xylene and mesitylene, or a mixture of o-xylene and mesitylene.

5. A covalent organic framework material for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption, as described in claim 4, and its preparation method thereof, characterized in that, The volume ratio of dioxane to mesitylene, m-xylene to mesitylene, or o-xylene to mesitylene is 1:9 to 9:

1.

6. The method for preparing a covalent organic framework material for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption according to claim 2, characterized in that, After the reaction was completed, the mixture was allowed to cool naturally to room temperature and the solid powder was collected by filtration. The powder was then washed, purified, and dried with an organic solvent.

7. A covalent organic framework material for direct air carbon dioxide capture and coupled with rapid solar photothermal desorption, as described in claim 6, and its preparation method thereof, characterized in that, The organic solvent includes one or more of N,N-dimethylformamide and tetrahydrofuran; the purification method includes Soxhlet extraction; the drying conditions are vacuum, 90-120°C. o C.

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