Preparation method and application of marine MOF-based porous liquid carbon capture absorbent

Abstract

The invention discloses a preparation method and application of a marine MOF-based porous liquid carbon capture absorbent, and belongs to the technical field of carbon dioxide capture materials. The invention aims to solve the problems that a traditional liquid absorbent is easy to degrade and volatilize, a traditional solid adsorption material has structural performance loss, mechanical fatigue, physical aging and slow mass and heat transfer, and large-scale industrial trapping is difficult to apply due to lack of fluidity and need of high-pressure adsorption. The method comprises the following steps: 1, preparing a ZIF-8 porous material; 2, preparing an MEA (at) ZIF-8 amino functional porous material; 3, preparing a steric hindrance solvent; and 4, preparing the marine MOF-based porous liquid carbon capture absorbent. The marine MOF-based porous liquid carbon capture absorbent is used for capturing and separating carbon dioxide gas. The preparation method disclosed by the invention is simple and convenient, mild in reaction condition, low in equipment requirement, small in modification on the existing equipment and beneficial to reducing the preparation and use cost, and has excellent performance in the aspect of carbon dioxide gas adsorption.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon dioxide capture materials, and specifically relates to a preparation method and application of a marine MOF-based porous liquid carbon capture absorbent. Background Art

[0002] In recent years, with the development of the economy, human dependence on fossil fuels has continued to deepen, resulting in increasing emissions of carbon dioxide. According to the assessment report released by the IPCC (Intergovermmental Panel On Climate Change), CO2, as the main greenhouse gas, its increased emissions will lead to rising global temperatures, triggering a series of frequent natural disasters and having a great impact on the human ecological environment. This issue has attracted great attention from all countries, and CO2 emission reduction has therefore become an urgent global issue.

[0003] As an important pillar of global trade, the shipping industry undertakes most of the world's trade transportation. Ships generally use marine diesel with high carbon content as fuel. With the continuous deepening of international trade, the number of ships has increased dramatically, and the greenhouse gas emissions of the shipping industry have also increased significantly. According to data released by the International Maritime Organization (IMO) in 2020, the annual CO2 emissions generated by the shipping industry have reached nearly 1 billion tons, accounting for about 3% of the total global CO2 emissions. Reducing carbon dioxide emissions from the shipping industry has become a global consensus. Although industrial carbon capture technology on land is relatively mature, the equipment is large in scale and cannot be used for a long time on ocean-going ships working in complex marine environments. Therefore, it is necessary to carry out targeted research on relevant shipping carbon capture as soon as possible.

[0004] So far, in response to the various policies and regulations issued by the International Maritime Organization (IMO) and its Maritime Environment Protection Committee (MEPC), many technologies to reduce ship exhaust emissions have been developed. The main measures include optimizing ship operating parameters, improving ship equipment technology, and exploring high-value alternative energy sources. Carbon capture and storage (CCS) technology, as part of the optimization of ship equipment technology, is considered to be an effective way to achieve carbon dioxide emissions and one of the most promising solutions.

[0005] At present, the common CO2 capture and separation technologies mainly include chemical absorption and solid adsorption. The chemical absorption method is widely used. Common absorbents (such as ionic liquids, alcohol amine absorbents, etc.) can realize continuous operation in the absorption and desorption process during flue gas treatment, greatly improve the utilization rate of absorbents, and require less modification to the existing power plant operating equipment. The chemical absorption method faces the problems of high operating costs and high energy consumption. The absorbent may also cause certain corrosion to the pipelines of the operating equipment, increasing the subsequent operation and maintenance costs. In contrast, the solid adsorption method has certain advantages in carbon dioxide capture, avoiding the corrosion of equipment during operation caused by the volatilization of liquid absorbents, reducing the subsequent operation and maintenance costs, and solid absorbents have a high specific surface area, excellent adsorption performance, low regeneration energy consumption and good stability. In current practical applications, solid absorbents are difficult to connect to existing pipelines due to their lack of fluidity, so it is difficult to achieve continuous operation, and they usually have problems such as mechanical fatigue and aging. Summary of the invention

[0006] The purpose of the present invention is to solve the problems that traditional liquid absorbents are easy to degrade and volatilize, traditional solid adsorption materials have structural performance loss, mechanical fatigue, physical aging and slow mass and heat transfer, and are difficult to apply industrial capture on a large scale due to lack of fluidity and high-pressure adsorption. A preparation method and application of a marine MOF-based porous liquid carbon capture absorbent is provided.

[0007] Based on the unique operating characteristics and exhaust emission properties of ocean-going ships, the present invention studies ship-based carbon capture technology suitable for ocean-going ships and provides a method for preparing a ship-based MOF-based porous liquid carbon capture absorbent. The prepared ship-based MOF-based porous liquid carbon capture absorbent has both the good fluidity of a liquid absorbent and the porosity of a solid adsorption material, and can be well used in the field of gas adsorption.

[0008] A method for preparing a marine MOF-based porous liquid carbon capture absorbent is specifically completed by the following steps:

[0009] 1. Preparation of ZIF-8 porous materials:

[0010] ①, dissolve Zn(NO3)2·6H2O in methanol to obtain mixed solution A;

[0011] ②, dissolve 2-methylimidazole in methanol to obtain a mixed solution B;

[0012] ③. Add the mixed solution A dropwise into the mixed solution B, stir and react for a period of time to obtain a reaction product;

[0013] ④, centrifuging the reaction product, washing the obtained precipitate, vacuum drying, and grinding to obtain a ZIF-8 porous material;

[0014] 2. Preparation of MEA@ZIF-8 amine-functionalized porous materials:

[0015] Ethanolamine was added to methanol, stirred at room temperature for a period of time, and then the ZIF-8 porous material was added, stirred and ultrasonicated at room temperature to make it fully mixed, then heated to remove excess methanol, and finally vacuum dried to obtain MEA@ZIF-8 amine-functionalized porous material;

[0016] 3. Preparation of hindered solvents:

[0017] Add choline chloride to ethanolamine, and heat and stir for a period of time to obtain a hindered solvent;

[0018] 4. Preparation of MOF-based porous liquid carbon capture absorbent for marine use:

[0019] The MEA@ZIF-8 amine-functionalized porous material was added into a solvent and ultrasonically dispersed for a period of time to obtain a marine MOF-based porous liquid carbon capture absorbent.

[0020] A marine MOF-based porous liquid carbon capture absorbent is used for capturing and separating carbon dioxide gas.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention provides a method for preparing a marine MOF-based porous liquid carbon capture absorbent, which uses ZIF-8 as the main unit and loads ethanolamine (MEA) to perform amine functionalization modification on it. The prepared MEA@ZIF-8 amine-functionalized porous material has a high specific surface area and considerable carbon dioxide adsorption performance; and the introduction of the porous main unit material makes the traditional solvent have a permanent pore structure; to a certain extent, it makes up for the defects of traditional liquid absorbents such as easy degradation and volatilization;

[0023] Second, the preparation method of the present invention is simple, the reaction conditions are mild, and the equipment requirements are low, and the modification of existing equipment is small, which is conducive to reducing the preparation and use costs, and has excellent performance in carbon dioxide gas adsorption;

[0024] 3. The method for preparing the marine MOF-based porous liquid carbon capture absorbent prepared by the present invention has a simple preparation process, can effectively reduce production costs, and has the advantages of controllable concentration of porous materials, large carbon dioxide absorption capacity, fast absorption rate, stable properties and low volatility; the steric solvent is a low eutectic solvent, which has the advantages of being green, environmentally friendly, non-toxic, controllable viscosity, and high thermal stability; it can make up for the defects of traditional liquid absorbents such as easy degradation and volatility, and the problem that solid materials are difficult to apply for industrial capture on a large scale due to lack of fluidity and high-pressure adsorption, and has both good fluidity of liquid absorbents and the porosity of solid adsorption materials.

[0025] The present invention is further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the laboratory CO2 capture device;

[0027] Figure 2 This is the XRD pattern of the MEA@ZIF-8 amine-functionalized porous material prepared in Example 1;

[0028] Figure 3 The SEM images of the ZIF-8 porous material and the MEA@ZIF-8 amine-functionalized porous material prepared in Example 1, wherein (a) is the ZIF-8 porous material and (b) is the MEA@ZIF-8 amine-functionalized porous material;

[0029] Figure 4 N2 adsorption-desorption curve and pore size distribution diagram of MEA@ZIF-8 amine-functionalized porous material prepared in Example 1;

[0030] Figure 5 The thermogravimetric analysis curves of the ZIF-8 porous material and the MEA@ZIF-8 amine-functionalized porous material prepared in Example 1, in which the black curve is the ZIF-8 porous material and the red curve is the MEA@ZIF-8 amine-functionalized porous material;

[0031] Figure 6 The graphs are the absorption rate and the absorption amount of carbon dioxide by the marine MOF-based porous liquid carbon capture absorbent prepared in Examples 1 to 3 and the liquid carbon capture absorbent prepared in the comparative example;

[0032] Figure 7 This is a diagram showing the fitting results of the carbon dioxide adsorption process of the MOF-based porous liquid carbon capture absorbent for ships prepared in Example 2 using pseudo-first-order, pseudo-second-order and Avrami fractional adsorption kinetic models. DETAILED DESCRIPTION

[0033] Specific implementation method 1: This implementation method is a method for preparing a marine MOF-based porous liquid carbon capture absorbent, which is specifically completed by the following steps:

[0034] 1. Preparation of ZIF-8 porous materials:

[0035] ①, dissolve Zn(NO3)2·6H2O in methanol to obtain mixed solution A;

[0036] ②, dissolve 2-methylimidazole in methanol to obtain a mixed solution B;

[0037] ③. Add the mixed solution A dropwise into the mixed solution B, stir and react for a period of time to obtain a reaction product;

[0038] ④, centrifuging the reaction product, washing the obtained precipitate, vacuum drying, and grinding to obtain a ZIF-8 porous material;

[0039] 2. Preparation of MEA@ZIF-8 amine-functionalized porous materials:

[0040] Ethanolamine was added to methanol, stirred at room temperature for a period of time, and then the ZIF-8 porous material was added, stirred and ultrasonicated at room temperature to make it fully mixed, then heated to remove excess methanol, and finally vacuum dried to obtain MEA@ZIF-8 amine-functionalized porous material;

[0041] 3. Preparation of hindered solvents:

[0042] Add choline chloride to ethanolamine, and heat and stir for a period of time to obtain a hindered solvent;

[0043] 4. Preparation of MOF-based porous liquid carbon capture absorbent for marine use:

[0044] The MEA@ZIF-8 amine-functionalized porous material was added into a solvent and ultrasonically dispersed for a period of time to obtain a marine MOF-based porous liquid carbon capture absorbent.

[0045] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that: the mass ratio of Zn(NO3)2·6H2O to methanol in step 1① is (1g-1.5g):40mL; the mass ratio of 2-methylimidazole to methanol in step 1② is (2g-3g):40mL. The other steps are the same as those in specific embodiment 1.

[0046] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that: the volume ratio of the mixed solution A to the mixed solution B in step 1 ③ is 1:1; the stirring reaction time in step 1 ③ is 1h to 3h, and the stirring reaction speed is 200r / min to 400r / min. The other steps are the same as those in specific implementation method 1 or 2.

[0047] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that: the centrifugal speed described in step 1 ④ is 4000 rpm to 6000 rpm, and the centrifugal time is 3 min to 5 min; the obtained precipitate is washed 3 to 5 times with methanol solution in step 1 ④; the vacuum drying temperature described in step 1 ④ is 60°C to 80°C, and the vacuum drying time is 4h to 8h. The other steps are the same as those of specific embodiments 1 to 3.

[0048] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the mass ratio of ethanolamine to ZIF-8 porous material in step 2 is 1:1; the mass ratio of ethanolamine to methanol in step 2 is (0.1 g to 1.5 g): 20 mL. The other steps are the same as those in specific embodiments 1 to 4.

[0049] Specific implementation method 6: The difference between this implementation method and specific implementation methods 1 to 5 is that the stirring time at room temperature in step 2 is 20min to 40min; the stirring and ultrasonic temperature at room temperature in step 2 is 25℃ to 30℃, the ultrasonic frequency is 40kHz, and the stirring and ultrasonic time is 1h to 2h; heating at 65℃ to 80℃ in step 2 to remove excess methanol; the vacuum drying temperature in step 2 is 60℃ to 80℃, and the vacuum drying time is 4h to 8h. The other steps are the same as those in specific implementation methods 1 to 5.

[0050] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the molar ratio of choline chloride to ethanolamine in step 3 is 1:(4-6). The other steps are the same as those of specific embodiments 1 to 6.

[0051] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the temperature of heating and stirring in step 3 is 70°C to 80°C, the time of heating and stirring is 3h to 5h, and the speed of heating and stirring is 200rpm to 600rpm. The other steps are the same as those of specific embodiments 1 to 7.

[0052] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that: the mass fraction of MEA@ZIF-8 amine-functionalized porous material in the marine MOF-based porous liquid carbon capture absorbent described in step 4 is 1% to 10%; the temperature of ultrasonic dispersion described in step 4 is 25°C to 30°C, the frequency of ultrasonic dispersion is 40kHz, and the time of ultrasonic dispersion is 1h to 3h. The other steps are the same as those of specific embodiments 1 to 8.

[0053] Specific embodiment 10: This embodiment is a marine MOF-based porous liquid carbon capture absorbent for capturing and separating carbon dioxide gas.

[0054] The following examples are used to verify the beneficial effects of the present invention:

[0055] Example 1: A method for preparing a marine MOF-based porous liquid carbon capture absorbent is specifically completed by the following steps:

[0056] 1. Preparation of ZIF-8 porous materials:

[0057] ①, dissolve 1.2g Zn(NO3)2·6H2O in 40mL methanol to obtain mixed solution A;

[0058] ②, dissolve 2.6 g of 2-methylimidazole in 40 mL of methanol to obtain a mixed solution B;

[0059] ③. Add the mixed solution A dropwise into the mixed solution B, and stir the mixture for 2 h at a stirring speed of 200 r / min to obtain a reaction product;

[0060] ④, centrifuging the reaction product, washing the obtained precipitate with deionized water for 3 times, and then vacuum drying at 80°C for 6h, and grinding to obtain ZIF-8 porous material;

[0061] The centrifugal speed in step 1 (4) is 6000 rpm and the centrifugal time is 5 min;

[0062] 2. Preparation of MEA@ZIF-8 amine-functionalized porous materials:

[0063] Ethanolamine was added to methanol and stirred at room temperature for 30 min, then the ZIF-8 porous material was added, stirred and ultrasonicated at room temperature for 1 h to fully mix, then heated at 65 ° C to remove excess methanol, and finally vacuum dried at 80 ° C for 6 h to obtain MEA@ZIF-8 amine-functionalized porous material;

[0064] The mass ratio of ethanolamine to ZIF-8 porous material described in step 2 is 1:1;

[0065] The mass ratio of ethanolamine to methanol in step 2 is 1 g:20 mL;

[0066] In step 2, the temperature of stirring and ultrasonication at room temperature is 25°C to 30°C, and the frequency of ultrasonication is 40kHz;

[0067] 3. Preparation of hindered solvents:

[0068] Add 22.86 g of choline chloride to 50 g of ethanolamine, place in a water bath at 80° C. and stir for 4 h at a constant temperature of 300 rpm to obtain a hindered solvent;

[0069] 4. Preparation of MOF-based porous liquid carbon capture absorbent for marine use:

[0070] The MEA@ZIF-8 amine-functionalized porous material was added into the inert solvent and ultrasonically dispersed for 2 h to obtain a marine MOF-based porous liquid carbon capture absorbent.

[0071] The mass fraction of the MEA@ZIF-8 amine-functionalized porous material in the marine MOF-based porous liquid carbon capture absorbent described in step 4 is 1%;

[0072] The temperature of the ultrasonic dispersion in step 4 is 25° C., and the frequency of the ultrasonic dispersion is 40 kHz.

[0073] Example 2: The difference between this example and Example 1 is that the mass fraction of the MEA@ZIF-8 amine-functionalized porous material in the marine MOF-based porous liquid carbon capture absorbent described in step 4 is 5%. The other steps and parameters are the same as those in Example 1.

[0074] Example 3: This example is different from Example 1 in that the mass fraction of the MEA@ZIF-8 amine-functionalized porous material in the marine MOF-based porous liquid carbon capture absorbent described in step 4 is 10%. The other steps and parameters are the same as those in Example 1.

[0075] Comparative Example: The difference between this example and Example 1 is that the mass fraction of the MEA@ZIF-8 amine-functionalized porous material in the marine MOF-based porous liquid carbon capture absorbent described in step 4 is 0%. The other steps and parameters are the same as those in Example 1.

[0076] Figure 2 This is the XRD pattern of the MEA@ZIF-8 amine-functionalized porous material prepared in Example 1;

[0077] like Figure 2 As shown in the figure, obvious characteristic diffraction peaks can be observed at 2θ=7.2°, 10.3°, 12.6°, 14.7°, 16.5° and 18.1°, which correspond to the characteristic peaks of the (011), (002), (112), (022), (013) and (022) crystal planes of ZIF-8, respectively, which is consistent with the literature reports, indicating that the introduction of MEA did not destroy its original crystal structure and the crystal structure of the prepared porous nanomaterial remained intact.

[0078] Figure 3 The SEM images of the ZIF-8 porous material and the MEA@ZIF-8 amine-functionalized porous material prepared in Example 1, wherein (a) is the ZIF-8 porous material and (b) is the MEA@ZIF-8 amine-functionalized porous material;

[0079] like Figure 3 As shown in (a), ZIF-8 has a rhombic polyhedral structure and presents a relatively concentrated particle size distribution; Figure 3 As shown in (b), the MEA@ZIF-8 amine-functionalized porous material has obvious agglomeration and protrusions. With the introduction of MEA, surface agglomeration occurs.

[0080] Figure 4N2 adsorption-desorption curve and pore size distribution diagram of MEA@ZIF-8 amine-functionalized porous material prepared in Example 1;

[0081] The results are as follows Figure 4 As shown in Figure 2, the N2 adsorption-desorption curve of MEA@ZIF-8 material is consistent with the type I isotherm, proving that the prepared material has a typical microporous structure. Figure 4 The pore size distribution curve in (b) shows that MEA@ZIF-8 has a large number of micropores. In addition, the pore characteristics of the sample are shown in Table 1. The specific surface area of ​​the main unit material MEA@ZIF-8 is 1026.9593 m 2 / g, pore volume is 0.4599cm 3 / g, and the pore diameter is 2.0314nm, which meets the requirements of fillers in synthetic porous liquids.

[0082] Table 1 MEA@ZIF-8 (pore characteristics)

[0083]

[0084] Figure 5 The thermogravimetric analysis curves of the ZIF-8 porous material and the MEA@ZIF-8 amine-functionalized porous material prepared in Example 1, in which the black curve is the ZIF-8 porous material and the red curve is the MEA@ZIF-8 amine-functionalized porous material;

[0085] like Figure 5 As shown in the figure, the decomposition process of MEA@ZIF-8 amine-functionalized porous material is similar to that of ZIF-8 porous material, which can be roughly divided into three stages. In the first stage, below 100℃, trace water in the sample volatilizes, resulting in trace mass loss. In the second stage, between 100℃ and 450℃, the residual solvent or a small amount of guest molecules in the sample are removed. MEA@ZIF-8 amine-functionalized porous material shows a slightly delayed decomposition phenomenon in this stage, indicating that the introduction of ethanolamine slows down the early heat loss of ZIF-8 and enhances the thermal stability of the material to a certain extent. In the third stage, after 450℃, the sample loses weight faster, the skeleton begins to collapse, the structure is gradually destroyed, and finally decomposes at high temperature; in this stage, the addition of ethanolamine increases the thermal decomposition temperature of MEA@ZIF-8 porous material and slows down the rate of mass loss; in summary, the two prepared materials have good stability. Moreover, the modified material not only maintains a thermal stability similar to that of ZIF-8, but also shows a thermal stability better than that of ZIF-8 under most temperature conditions, showing its potential in industrial applications.

[0086] Application examples:

[0087] The marine MOF-based porous liquid carbon capture absorbent prepared in Examples 1 to 3 and the liquid carbon capture absorbent prepared in the comparative example were used to absorb CO2 gas; a bubbling absorption method was used to conduct a carbon dioxide absorption experiment. The specific steps are:

[0088] Experimental setup Figure 1 As shown, equal amounts of the absorbents prepared in the above embodiments and comparative embodiments are weighed and added into a gas absorption bottle, a gas mixing device is used to prepare a mixed gas of CO2:N2=15:85 to simulate ship exhaust gas, the mixed gas is passed into the absorption bottle, and a CO2 infrared flue gas analyzer is used to monitor the carbon dioxide concentration at the outlet of the absorption bottle in real time; when the reading of the flue gas analyzer is stable and no longer changes, the absorption is completed.

[0089] Figure 6 The graphs are the absorption rate and the absorption amount of carbon dioxide by the marine MOF-based porous liquid carbon capture absorbent prepared in Examples 1 to 3 and the liquid carbon capture absorbent prepared in the comparative example;

[0090] from Figure 6 It can be seen that the addition of the main unit (MEA@ZIF-8 amine-functionalized porous material) has a certain influence on the absorption rate and absorption capacity of carbon dioxide gas of the absorbent. Figure 6 As shown in (a), in the initial stage, the CO2 absorption rate of all samples is relatively high, and the absorption rate gradually decreases over time. The absorbent with 10% MEA@ZIF-8 added (the marine MOF-based porous liquid carbon capture absorbent prepared in Example 3) has a relatively fast absorption rate in the initial stage, but its absorption rate also decreases faster. In contrast, the absorbent with 5% MEA@ZIF-8 added (the marine MOF-based porous liquid carbon capture absorbent prepared in Example 2) has better adsorption performance, especially within 10-30 minutes, the absorption rate remains at a high level. The absorbents with 0% (comparative example) and 1% MEA@ZIF-8 added (the marine MOF-based porous liquid carbon capture absorbent prepared in Example 1) show slower absorption rates, and their absorption rates tend to stabilize earlier over time. As shown Figure 6 As shown in (b), the absorption amount of the absorbent with 5% MEA@ZIF-8 mass fraction is the highest, and it maintains a rapid growth throughout the experiment. Although the absorbent with 10% MEA@ZIF-8 mass fraction has a faster initial adsorption, the absorption growth rate slows down in the later period (after 30 minutes). The absorbents with 0% and 1% MEA@ZIF-8 have the lowest absorption amount, and the absorption amount increases relatively slowly with time. In summary, for CO2 adsorption performance, a porous liquid absorbent with 5% MEA@ZIF-8 may be the best choice, which can not only maintain a high initial absorption rate, but also adsorb more CO2 over a long period of time.

[0091] Table 2 shows the fitting parameters of different kinetic models.

[0092] from Figure 7 As can be seen from Table 2, the equilibrium adsorption capacities fitted by the pseudo-first-order and pseudo-second-order kinetic models are 8.50mmol / g and 12.34mmol / g, respectively, which are quite different from the experimental value of 7.24mmol / g, indicating that the adsorption process of the absorbent is not a single physical adsorption or chemical adsorption process. In contrast, the correlation coefficient (R 2 ) is the highest, which is 0.998, and the fitting error (ARE) is the lowest, which is only 2.76%, and its fitted equilibrium adsorption amount is closest to the experimental value. This shows that the Avrami fractional-order kinetic model is more suitable for describing the CO2 adsorption process of the MOF-based porous liquid. The good fitting correlation of the Avrami fractional-order kinetic model shows that the adsorption of CO2 by the absorbent is not a simple physical adsorption or chemical adsorption, but a complex multi-path adsorption process involving adsorption sites and adsorption activity. The reaction order n in the Avrami fractional-order kinetic model is a non-integer greater than 1. It is further shown that the adsorption process includes both single-layer adsorption and multi-phase multi-layer adsorption.

[0093] Table 2 Fitting parameters of different kinetic models

[0094]

[0095]

[0096] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a marine MOF-based porous liquid carbon capture absorbent, characterized in that The preparation method is specifically completed according to the following steps:

1. Preparation of ZIF-8 porous materials: ①, dissolve Zn(NO3)2·6H2O in methanol to obtain mixed solution A; ②, dissolve 2-methylimidazole in methanol to obtain a mixed solution B; ③. Add the mixed solution A dropwise into the mixed solution B, stir and react for a period of time to obtain a reaction product; ④, centrifuging the reaction product, washing the obtained precipitate, vacuum drying, and grinding to obtain a ZIF-8 porous material; 2. Preparation of MEA@ZIF-8 amine-functionalized porous materials: Ethanolamine was added to methanol, stirred at room temperature for a period of time, and then the ZIF-8 porous material was added, stirred and ultrasonicated at room temperature to make it fully mixed, then heated to remove excess methanol, and finally vacuum dried to obtain MEA@ZIF-8 amine-functionalized porous material; 3. Preparation of hindered solvents: Add choline chloride to ethanolamine, and heat and stir for a period of time to obtain a hindered solvent; 4. Preparation of MOF-based porous liquid carbon capture absorbent for marine use: The MEA@ZIF-8 amine-functionalized porous material was added into a solvent and ultrasonically dispersed for a period of time to obtain a marine MOF-based porous liquid carbon capture absorbent.

2. The method for preparing a marine MOF-based porous liquid carbon capture absorbent according to claim 1, characterized in that The mass ratio of Zn(NO3)2·6H2O described in step 1① to the volume ratio of methanol is (1g~1.5g):40mL; the mass ratio of 2-methylimidazole described in step 1② to the volume ratio of methanol is (2g~3g):40mL.

3. The method for preparing a marine MOF-based porous liquid carbon capture absorbent according to claim 1, characterized in that The volume ratio of the mixed solution A to the mixed solution B described in step 1③ is 1:1; the stirring reaction time described in step 1③ is 1h to 3h, and the stirring reaction speed is 200r / min to 400r / min.

4. The method for preparing a marine MOF-based porous liquid carbon capture absorbent according to claim 1, characterized in that The centrifugal speed described in step 1④ is 4000rpm~6000rpm, and the centrifugal time is 3min~5min; In step 1④, the precipitate obtained is washed 3 times~5 times with methanol solution; The vacuum drying temperature described in step 1④ is 60℃~80℃, and the vacuum drying time is 4h~8h.

5. The method for preparing a marine MOF-based porous liquid carbon capture absorbent according to claim 1, characterized in that The mass ratio of the ethanolamine described in step 2 to the ZIF-8 porous material is 1:1; the mass ratio of the ethanolamine described in step 2 to the volume ratio of methanol is (0.1 g to 1.5 g): 20 mL.

6. The method for preparing a marine MOF-based porous liquid carbon capture absorbent according to claim 1, characterized in that The stirring time at room temperature in step 2 is 20 min to 40 min; the temperature of stirring and ultrasonicating at room temperature in step 2 is 25°C to 30°C, the frequency of ultrasonicating is 40kHz, and the time of stirring and ultrasonicating is 1h to 2h; heating at 65°C to 80°C to remove excess methanol in step 2; the temperature of vacuum drying in step 2 is 60°C to 80°C, and the time of vacuum drying is 4h to 8h.

7. The method for preparing a marine MOF-based porous liquid carbon capture absorbent according to claim 1, characterized in that The molar ratio of choline chloride to ethanolamine in step 3 is 1:(4-6).

8. The method for preparing a marine MOF-based porous liquid carbon capture absorbent according to claim 1, characterized in that The temperature of the heating and stirring in step 3 is 70° C. to 80° C., the time of the heating and stirring is 3 h to 5 h, and the speed of the heating and stirring is 200 rpm to 600 rpm.

9. The method for preparing a marine MOF-based porous liquid carbon capture absorbent according to claim 1, characterized in that The mass fraction of MEA@ZIF-8 amine-functionalized porous material in the marine MOF-based porous liquid carbon capture absorbent described in step 4 is 1% to 10%; the temperature of ultrasonic dispersion described in step 4 is 25°C to 30°C, the frequency of ultrasonic dispersion is 40kHz, and the time of ultrasonic dispersion is 1h to 3h.

10. Use of a marine MOF-based porous liquid carbon capture absorbent prepared by the preparation method according to claim 1, characterized in that A marine MOF-based porous liquid carbon capture absorbent is used for capturing and separating carbon dioxide gas.

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