A porous aluminum-based carrier and a preparation method thereof, a co2 adsorbent and application thereof

Abstract

The application discloses a porous aluminum-based carrier and a preparation method thereof, a CO2 adsorbent and application thereof. The preparation of the porous aluminum-based carrier comprises the following steps: segmental aging: a solution containing pseudo-boehmite is subjected to two-stage aging, the first stage is stirring aging, and the second stage is standing aging, the two kinds of aging modes are combined to improve the crystallinity of the pseudo-boehmite; organic solvent washing and pore expansion: the pseudo-boehmite is filtered out, and is subjected to water washing first and then organic solvent washing; segmental drying: low-temperature air blowing drying and vacuum drying are combined, the drying mode, the drying temperature and the solvent evaporation rate during drying are adjusted to avoid pore shrinkage or collapse caused by excessively high drying temperature and excessively fast solvent evaporation speed. The preparation of the porous aluminum-based carrier is simple in operation and low in energy consumption, and the CO2 adsorbent prepared from the porous aluminum-based carrier and an organic amine has excellent adsorption performance such as high adsorption capacity, fast adsorption rate and high stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material synthesis and gas adsorption, and particularly relates to a porous aluminum-based carrier and a preparation method thereof, a CO2 adsorbent and application thereof. BACKGROUND

[0002] Solid amine adsorbents are widely used in the field of CO2 capture and storage technology, and mesoporous molecular sieves are often used as carrier materials of solid amine adsorbents due to their large pore volume, high specific surface area and adjustable pore size.

[0003] However, the preparation process of mesoporous carrier materials often involves the addition of a template agent and a pore-expanding agent and high-temperature calcination. The addition of the template agent and the pore-expanding agent can introduce impurities and is expensive, and the template agent and the pore-expanding agent need to be removed by high-temperature calcination, which makes the preparation process of the mesoporous material too complex, the material cost is too high, and the energy consumption is high. SUMMARY

[0004] The present application discloses a porous aluminum-based carrier and a preparation method thereof, a CO2 adsorbent and application thereof, and the preparation method of the porous aluminum-based carrier is simple in operation and low in cost.

[0005] To achieve the above-mentioned purpose, in a first aspect, the present application discloses a preparation method of a porous aluminum-based carrier, and the preparation method comprises the following steps:

[0006] Segmented aging: the solution containing pseudo-boehmite is aged in two segments, the first segment is stirred and aged at 50 DEG C to 80 DEG C, the stirring rate is 100 rad / min to 500 rad / min, and the aging time is 1 h to 5 h, and the second segment is aged at 70 DEG C to 150 DEG C, and the aging time is 1 h to 8 h;

[0007] Organic solvent washing and pore expansion: the precipitate in the solution containing pseudo-boehmite is filtered out to obtain pseudo-boehmite, and the pseudo-boehmite is washed with water first and then with an organic solvent;

[0008] Segmented drying: the pseudo-boehmite washed with the organic solvent is dried in segments, in the first segment, the organic solvent content in the pseudo-boehmite is 15 wt.% to 60 wt.%, and the pseudo-boehmite is dried by low-temperature air blowing at 50 DEG C to 90 DEG C, and the solvent evaporation rate is controlled at 1.5 wt.%·h -1 ~ 4 wt.%·h -1 , in the second segment, the organic solvent content in the pseudo-boehmite is less than 15 wt.%, and the pseudo-boehmite is dried in vacuum at 50 DEG C to 130 DEG C, and the solvent evaporation rate is controlled at 0.5 wt.%·h -1 ~ 1.5 wt.%·h -1 .

[0009] As an optional implementation, in the embodiment of the first aspect of the present application, when the pseudo-boehmite is washed by the organic solvent, the organic solvent and the pseudo-boehmite are mixed, stirred at 25-80℃ for 0.5-3h at a stirring rate of 100-500rad / min, and then filtered while hot,

[0010] wherein the washing is performed for 1-5 times, and the mass ratio of the organic solvent to the pseudo-boehmite is 5:1 to 20:1.

[0011] As an optional implementation, in the embodiment of the first aspect of the present application, the organic solvent comprises one or more of ethanol, acetic acid, propanol, acetone, glycerol and butanol.

[0012] As an optional implementation, in the embodiment of the first aspect of the present application, the dried pseudo-boehmite is ground to 200 mesh or less.

[0013] In the second aspect, the present application further discloses a porous aluminum-based carrier prepared by the preparation method of the first aspect.

[0014] Further, the porous aluminum-based carrier has a pore volume of greater than or equal to 2.0cm 3 / g, an average pore size of 15-20nm, and a specific surface area of greater than or equal to 480m 2 / g.

[0015] In the third aspect, the present application further discloses a CO2 adsorbent comprising the porous aluminum-based carrier of the second aspect and an active substance loaded on the porous aluminum-based carrier.

[0016] wherein the active substance is an amine substance, and the loading amount of the active substance in the CO2 adsorbent is 40%-70%.

[0017] In the fourth aspect, the present application further discloses an application of the CO2 adsorbent, which is used for adsorbing carbon dioxide and / or desorbing and regenerating after adsorbing carbon dioxide.

[0018] As an optional implementation, when the CO2 adsorbent is used for adsorbing carbon dioxide, the adsorption conditions are as follows: the CO2 is adsorbed in a CO2 gas stream of 4vol.%-100vol.% at 60-100℃, and the CO2 adsorption amount of the CO2 adsorbent is greater than or equal to 200mg / g.

[0019] Further, the CO2 adsorbent can be regenerated by desorption under the following conditions: desorption under inert gas or vacuum at 100-150 DEG C for 10-50 minutes.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] The porous aluminum-based carrier, the preparation method thereof, the CO2 adsorbent and the application thereof are disclosed. In the preparation method, the solution containing pseudo-boehmite is subjected to two-stage aging before being washed with an organic solvent. The stirring aging can make the generated pseudo-boehmite in a fully dispersed state, thereby controlling the growth rate of the crystallization thereof. The standing aging can make the pseudo-boehmite crystallization more complete. Through the combination of the stirring aging and the standing aging, on the one hand, the crystallization process can be better controlled, the grain growth is slower and more fine, and the pore structure of the pseudo-boehmite is prevented from being damaged due to the rapid grain growth. On the other hand, the crystallinity of the pseudo-boehmite can be improved, the internal crystal water of the pseudo-boehmite is combined more closely, and the crystal water is prevented from being washed out in the organic solvent washing process. When the organic solvent is washed, on the one hand, the adsorbed water in the pore of the pseudo-boehmite is replaced by the organic solvent with small surface tension, and the pore shrinkage caused by the capillary force in the drying process is avoided. On the other hand, the small water molecules are replaced by the large organic solvent molecules, and the organic solvent molecules enter the pore of the pseudo-boehmite, thereby further expanding the pore. The above-mentioned combination of the aging and the organic solvent washing can smoothly expand the pore of the pseudo-boehmite, the pore collapse of the pseudo-boehmite due to the removal of most of the crystal water in the organic solvent washing process is avoided, and the step of removing the combined organic solvent molecules in the pseudo-boehmite by high-temperature calcination is also avoided. The pseudo-boehmite after the organic solvent washing contains a large amount of organic solvent, and the content is generally 15wt.%-60wt.%. In order to realize the rapid drying at low temperature as much as possible, the preparation method adopts the segmented drying. When the content of the organic solvent in the pseudo-boehmite is 15wt.%-60wt.%, the low-temperature drying is performed at 50-90 DEG C, so as to evaporate most of the organic solvent. The evaporation rate of the solvent is controlled to be 1.5wt.%·h -1 -4wt.%·h -1 When the content of the organic solvent is less than 15wt.%, the vacuum drying is adopted to reduce the boiling point of the solvent, and then the organic solvent in the pseudo-boehmite is further removed. The temperature of the vacuum drying is set to be 50-130 DEG C, and the evaporation rate of the solvent is controlled to be 0.5wt.%·h -1 -1.5wt.%·h -1By adjusting the drying method, drying temperature and solvent evaporation rate during drying, the pore shrinkage or collapse caused by too high drying temperature and too fast solvent evaporation rate is avoided. The organic combination of each step makes the prepared porous aluminum-based carrier have large pore volume and suitable pore size, which can be used as a carrier to prepare a CO2 adsorbent. The preparation method is simple in operation, can effectively simplify the process flow, and is conducive to reducing the production cost. At the same time, when the porous aluminum-based carrier is used to prepare a CO2 adsorbent, it has excellent adsorption performance such as high adsorption capacity, fast adsorption rate and high stability. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the present application will be briefly introduced as follows. Obviously, the drawings described in the following are only some embodiments and comparative examples of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0023] Figure 1 is a scanning electron microscope image of the porous aluminum-based carrier provided by the first embodiment of the present application.

[0024] Figure 2 is a scanning electron microscope image of the aluminum-based carrier provided by the second comparative example of the present application.

[0025] Figure 3 is a N2 adsorption curve of the porous aluminum-based carrier provided by the first embodiment of the present application and the aluminum-based carriers provided by the second comparative example and the sixth comparative example of the present application.

[0026] Figure 4 is a CO2 adsorption experiment graph of the solid amine adsorbent provided by the first test example, the second comparative test example and the sixth comparative test example of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0028] It should be noted that the terms "include" and "have" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusion.

[0029] The solid amine adsorbent has low energy consumption, small corrosion and wide application scene, is widely used in the field of CO2 capture and storage technology, and the mesoporous molecular sieve is often used as a carrier material of the solid amine adsorbent due to large pore volume, high specific surface area and adjustable pore size. However, the mesoporous carrier material such as MCM-41 and SBA-15 often needs to add an expensive template agent in the synthesis process, and needs to be calcined at high temperature to remove the template agent, and the pore adjustment process often involves adding a pore expander, heating azeotrope with an organic solvent, high-temperature calcination and other operations, so that the synthesis process of the mesoporous material is too complex, the material cost is too high, the environment is polluted greatly and the energy consumption is high. At present, a new solid amine adsorbent with simple preparation method, easily available material, small environmental pollution and low energy consumption is urgently needed, and the adsorbent needs to have high CO2 adsorption capacity, fast adsorption kinetics and good adsorption-desorption stability.

[0030] The embodiment of the present application discloses a preparation method of a porous aluminum-based carrier, and the preparation method comprises the following steps:

[0031] Segmented aging: the solution containing pseudo-boehmite is aged in two segments, the first segment is stirred and aged at 50-80 DEG C, the stirring rate is 100-500 rad / min, and the aging time is 1-5 h, and the second segment is statically aged at 70-150 DEG C, and the aging time is 1-8 h;

[0032] Organic solvent washing and pore expansion: the precipitate in the solution containing pseudo-boehmite is filtered out to obtain pseudo-boehmite, and the pseudo-boehmite is washed with water first and then with an organic solvent;

[0033] Segmented drying: the pseudo-boehmite washed with the organic solvent is dried in segments, in the first segment, the organic solvent content in the pseudo-boehmite is 15-60 wt.%, and the pseudo-boehmite is dried by low-temperature air blowing at 50-90 DEG C, the solvent evaporation rate is controlled to be 1.5 wt.% h -1 -4 wt.% h -1 , in the second segment, the organic solvent content in the pseudo-boehmite is less than 15 wt.%, and the pseudo-boehmite is vacuum dried at 50-130 DEG C, and the solvent evaporation rate is controlled to be 0.5 wt.% h -1 -1.5 wt.% h -1 .

[0034] By combining stirring aging and static aging, the crystallization process can be better controlled, the grain growth is slower and finer, and the pseudo-boehmite with higher crystallinity and more stable pore structure is obtained; by organic solvent washing, the adsorbed water in the pore of the pseudo-boehmite is replaced by the organic solvent with small surface tension, avoiding the pore shrinkage caused by capillary force in the drying process, at the same time, the small water molecules are replaced by the larger organic solvent molecules, and the organic solvent molecules enter the pore of the pseudo-boehmite, further expanding the pore, which is simple to operate and avoids the step of removing the combined organic solvent molecules in the pseudo-boehmite by high-temperature calcination and cracking; the segmented drying helps to realize low-temperature rapid drying, when the content of the organic solvent in the pseudo-boehmite is high, the low-temperature air drying is used to evaporate most of the organic solvent, and when the content of the organic solvent is low, the vacuum drying is used to reduce the boiling point of the solvent, and then further remove the organic solvent in the pseudo-boehmite. By adjusting the drying method, drying temperature and solvent evaporation rate, the pore shrinkage or collapse caused by too high drying temperature and too fast solvent evaporation rate is avoided.

[0035] It can be understood that, in the segmented aging step, for the first aging, the aging temperature is 50℃-80℃, including any point value in the temperature range, for example, 50℃, 60℃, 70℃, 80℃, etc.; the stirring rate is 100 rad / min-500 rad / min, including any point value in the rate range, for example, 100 rad / min, 200 rad / min, 300 rad / min, 400 rad / min, 500 rad / min, etc.; the aging time is 1h-5h, including any point value in the time range, for example, 1h, 2h, 3h, 4h, 5h, etc. For the second aging, the aging temperature is 70℃-150℃, including any point value in the temperature range, for example, 70℃, 90℃, 110℃, 130℃, 150℃, etc.; the aging time is 1h-8h, including any point value in the time range, for example, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, etc.

[0036] It can be understood that, in the segmented drying step, the content of the organic solvent in the pseudo-boehmite refers to the mass percentage of the organic solvent in the pseudo-boehmite, which can be determined by calculating the mass of the pre-dried pseudo-boehmite, for example, the content of the organic solvent in the pseudo-boehmite can be measured by the following method: after preparing the solution containing the pseudo-boehmite, filtering, and drying the filtered pseudo-boehmite, the mass of the pseudo-boehmite is obtained; after filtering the solution containing the pseudo-boehmite, washing with water first, then washing with the organic solvent, filtering, and measuring the mass of the precipitate, the mass of the pseudo-boehmite after the organic solvent washing is obtained. The mass percentage of the organic solvent in the pseudo-boehmite is The solvent evaporation rate can be obtained by measuring the mass of solvent reduced due to evaporation per unit time, i.e.

[0037] The first drying section has a drying temperature of 50-90°C, including any value within the range, such as 50°C, 60°C, 70°C, 80°C, 90°C, etc. The second drying section has a drying temperature of 50-130°C, including any value within the range, such as 50°C, 70°C, 90°C, 110°C, 130°C, etc.

[0038] Optionally, when the organic solvent is used to wash the pseudo-boehmite, the organic solvent and the pseudo-boehmite are mixed and stirred at 25-80°C for 0.5-3h at a stirring rate of 100-500rad / min, and then filtered while hot. The washing is performed 1-5 times, and the mass ratio of the organic solvent to the pseudo-boehmite is 5:1 to 20:1 each time.

[0039] It can be understood that the temperature of 25-80°C includes any value within the range, such as 25°C, 40°C, 55°C, 80°C, etc. The stirring time of 0.5-3h includes any value within the range, such as 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, etc. The stirring rate of 100-500rad / min includes any value within the range, such as 100rad / min, 200rad / min, 300rad / min, 400rad / min, 500rad / min, etc. The washing times of 1-5 times includes any value within the range, such as 1 time, 2 times, 3 times, 4 times, 5 times, etc. The mass ratio of 5:1 to 20:1 includes any value within the range, such as 5:1, 10:1, 15:1, 20:1, etc.

[0040] Optionally, the organic solvent includes one or more of ethanol, acetic acid, propanol, acetone, glycerol, and butanol.

[0041] Optionally, the dried pseudo-boehmite is ground to 200 mesh or less.

[0042] Compared with the way of expanding the pore by the azeotropy of the organic solvent and the porous material, the organic solvent washing expansion way used in the scheme is simpler in operation, but it has higher requirements for the stability of the pore structure of the porous material. For pseudo-boehmite, the higher the crystallinity, the more stable the pore structure. Only the pseudo-boehmite with high crystallinity can be expanded by the organic reagent, and the pseudo-boehmite with poor crystallinity is easy to take away the crystal water when washed with the organic reagent, resulting in the collapse of the pore. In the present application, the crystallinity of the pseudo-boehmite is effectively improved by twice aging, and the pore expansion is successfully achieved by the organic solvent washing. In the subsequent drying and removal of the organic solvent, the pore stability of the pseudo-boehmite after the pore expansion is further ensured by the relatively mild step-by-step drying, and the problem of a small amount of pore collapse caused by high-temperature drying is avoided.

[0043] The present application also provides a porous aluminum-based carrier prepared by the preparation method as described above.

[0044] The present application also provides a CO2 adsorbent comprising a carrier and an active substance loaded on the carrier, wherein the carrier is the porous aluminum-based carrier as described above, and the active substance is an amine substance, and the loading amount of the active substance in the CO2 adsorbent is 40% to 70%.

[0045] The present application also provides an application of the CO2 adsorbent for adsorbing carbon dioxide and / or desorbing and regenerating after adsorbing carbon dioxide.

[0046] Further, for adsorption, the CO2 adsorption amount of the CO2 adsorbent is greater than or equal to 200mg / g under the condition of 60℃ to 100℃ and in a CO2 gas flow of 4vol.% to 100vol.%.

[0047] Further, for desorption and regeneration, the CO2 adsorbent can be desorbed and regenerated under the condition of 100℃ to 150℃ in an inert gas or vacuum for 10min to 50min.

[0048] The technical solutions provided by the present application will be further described below with reference to the embodiments and the accompanying drawings.

[0049] Embodiment One

[0050] The present embodiment one discloses a porous aluminum-based carrier, and the preparation method thereof comprises the following steps:

[0051] Preparation of the solution containing pseudo-boehmite: 20 g / L sodium aluminate solution was placed in a reaction kettle, aeration head with a pore size of 1 μm was placed in the reaction kettle, 15 vol.% CO2 gas with a flow rate of 800 mL / min per liter of sodium aluminate solution was introduced through the aeration head, and the reaction was carried out at 25°C until the pH of the reaction system dropped to 9.8, then the reaction was stopped, to obtain the solution containing pseudo-boehmite;

[0052] Segmented aging: the solution containing pseudo-boehmite was transferred to a water bath, and was aged at 60°C with a stirring rate of 100 rad / min for 3 h, and then was aged at 70°C for 3 h;

[0053] Organic solvent washing and hole expansion: the precipitate in the solution containing pseudo-boehmite was filtered to obtain pseudo-boehmite, the pseudo-boehmite was washed with deionized water at 25°C for 3 times, then butanol was used to mix the pseudo-boehmite with a mass ratio of 1:10, and then was stirred at 50°C with a stirring rate of 200 rad / min for 1 h, and was quickly filtered while hot, and the washing process was repeated for 3 times;

[0054] Segmented drying: the washed pseudo-boehmite was air-dried at 70°C for 8 h, and then was transferred to a vacuum drying oven at 110°C for drying for 12 h, and was taken out and cooled, and was ground into a powder with a particle size of 200 mesh, to obtain the porous aluminum-based carrier.

[0055] Please refer to Figure 1 , Figure 1 is a scanning electron microscope image of the porous aluminum-based carrier provided in Example One, and it can be seen that the surface of each small ball of the porous aluminum-based carrier is covered with "tentacles", and the "tentacles" between the small balls interweave with each other, so that the pore structure of the carrier is exceptionally developed, and the formed pores are relatively uniform, the pore size is relatively large, and the pore size is about 15-20 nm.

[0056] Example Two

[0057] The Example Two further discloses a porous aluminum-based carrier, and a preparation method thereof includes the following steps:

[0058] Preparation of the solution containing pseudo-boehmite: the preparation method is the same as that in Example One;

[0059] Segmented aging: the solution containing pseudo-boehmite was transferred to a water bath, and was aged at 50°C with a stirring rate of 200 rad / min for 2 h, and then was aged at 80°C for 3 h;

[0060] Organic solvent washing and pore expansion: the precipitate in the solution containing pseudo-boehmite was filtered out to obtain pseudo-boehmite, the pseudo-boehmite was repeatedly washed with deionized water at 25°C for 5 times, then glycerol was used to mix the pseudo-boehmite and the glycerol at a mass ratio of 1:20, then stirring was carried out at 80°C and a stirring rate of 200 rad / min for 2 h, rapid filtration was carried out while hot, and the washing process was repeated for 3 times;

[0061] Segmented drying: the washed pseudo-boehmite was placed in a blast drying oven at 80°C for 12 h, then was transferred to a vacuum drying oven at 130°C for drying for 12 h, was taken out and cooled, and was ground into a powder with a particle size of 200 mesh or less, so that a porous aluminum-based carrier was prepared.

[0062] Example Three

[0063] The example three also discloses a porous aluminum-based carrier, and a preparation method thereof includes the following steps:

[0064] Preparation of a solution containing pseudo-boehmite: the preparation method is the same as that in example one;

[0065] Segmented aging: the solution containing pseudo-boehmite was transferred to a water bath, and was aged at 80°C and a stirring rate of 300 rad / min for 1 h, and then was aged at 100°C for 2 h;

[0066] Organic solvent washing and pore expansion: the precipitate in the solution containing pseudo-boehmite was filtered out to obtain pseudo-boehmite, the pseudo-boehmite was repeatedly washed with deionized water at 25°C for 5 times, then glycerol was used to mix the pseudo-boehmite and the glycerol at a mass ratio of 1:20, then stirring was carried out at 80°C and a stirring rate of 200 rad / min for 2 h, rapid filtration was carried out while hot, and the washing process was repeated for 3 times;

[0067] Segmented drying: the washed pseudo-boehmite was placed in a blast drying oven at 80°C for 12 h, then was transferred to a vacuum drying oven at 130°C for drying for 12 h, was taken out and cooled, and was ground into a powder with a particle size of 200 mesh or less, so that a porous aluminum-based carrier was prepared.

[0068] Example Four

[0069] The example four also discloses a porous aluminum-based carrier, and a preparation method thereof includes the following steps:

[0070] Preparation of a solution containing pseudo-boehmite: the preparation method is the same as that in example one;

[0071] Segmented aging: the solution containing pseudo-boehmite was transferred to a water bath, and was aged at 80°C and a stirring rate of 300 rad / min for 1 h, and then was aged at 100°C for 2 h;

[0072] Organic solvent washing and pore expansion: the precipitate in the solution containing pseudo-boehmite was filtered out to obtain pseudo-boehmite, and the pseudo-boehmite was repeatedly washed with deionized water at 25°C for 5 times, then mixed with butanol according to a mass ratio of pseudo-boehmite to butanol of 1:5, then stirred at 40°C and a stirring rate of 200 rad / min for 3 h, quickly filtered while hot, and the washing process was repeated for 3 times;

[0073] Segmented drying: the washed pseudo-boehmite was placed in a common oven at 90°C for drying for 12 h, then transferred to a vacuum drying oven at 110°C for drying for 12 h, taken out and cooled, and ground into a powder with a particle size of 200 mesh or less, thereby obtaining the porous aluminum-based carrier.

[0074] Example Five

[0075] This Example Five discloses a porous aluminum-based carrier, and a preparation method thereof includes the following steps:

[0076] Preparation of a solution containing pseudo-boehmite: the preparation method is the same as that in Example One;

[0077] Segmented aging: the solution containing pseudo-boehmite was transferred to a water bath, and aged at 70°C and a stirring rate of 100 rad / min for 2 h, and then aged at 90°C for 1 h;

[0078] Organic solvent washing and pore expansion: the precipitate in the solution containing pseudo-boehmite was filtered out to obtain pseudo-boehmite, and the pseudo-boehmite was repeatedly washed with deionized water at 25°C for 5 times, then mixed with butanol according to a mass ratio of pseudo-boehmite to butanol of 1:5, then stirred at 40°C and a stirring rate of 200 rad / min for 3 h, quickly filtered while hot, and the washing process was repeated for 3 times;

[0079] Segmented drying: the washed pseudo-boehmite was placed in a common oven at 90°C for drying for 12 h, then transferred to a vacuum drying oven at 110°C for drying for 12 h, taken out and cooled, and ground into a powder with a particle size of 200 mesh or less, thereby obtaining the porous aluminum-based carrier.

[0080] Comparative Example One

[0081] This Comparative Example One provides an aluminum-based carrier, and the preparation method thereof is different from that in Example One only in that the segmented aging step and the organic solvent washing and pore expansion step are not performed. In this Comparative Example One, the precipitate in the solution containing pseudo-boehmite was filtered out to obtain pseudo-boehmite, and the pseudo-boehmite was repeatedly washed with deionized water at 25°C for 3 times, and then the segmented drying step was performed.

[0082] Comparative Example Two

[0083] Comparative Example 2 provides an aluminum-based carrier, the preparation method of which is different from that of Example 1 only in that the step of segmental aging is not performed. In Comparative Example 2, the precipitate in the solution containing pseudo-boehmite is filtered out to obtain pseudo-boehmite, and the step of organic solvent washing and pore expansion is performed.

[0084] Referring to Figure 2 , Figure 2 The scanning electron microscope image of the aluminum-based carrier of Comparative Example 2 shows that the aluminum-based carrier is composed of many smooth and small particles tightly packed together, and almost no pores can be seen between the particles, and no pores can be seen inside the particles, and the pore structure of the carrier is very underdeveloped.

[0085] Comparative Example 3

[0086] Comparative Example 3 provides an aluminum-based carrier, the preparation method of which is different from that of Example 1 only in that the step of organic solvent washing and pore expansion is not performed. In Comparative Example 3, after the step of segmental aging is performed, the pseudo-boehmite after aging is repeatedly washed 3 times using deionized water at 25°C, i.e., the step of segmental drying is performed.

[0087] Comparative Example 4

[0088] Comparative Example 4 provides an aluminum-based carrier, the preparation method of which is different from that of Example 1 only in that one-stage aging instead of segmental aging is performed. The aging condition is that the solution containing pseudo-boehmite is transferred to a water bath, and is aged at 60°C with a stirring rate of 100 rad / min for 3h.

[0089] Comparative Example 5

[0090] Comparative Example 5 provides an aluminum-based carrier, the preparation method of which is different from that of Example 1 only in that one-stage drying instead of segmental drying is performed. The drying condition is that the washed pseudo-boehmite is placed in a 120°C ordinary oven for drying for 20h, and is taken out and cooled, and is ground into a powder with a particle size of 200 mesh or less.

[0091] Comparative Example 6

[0092] Comparative Example 6 provides an aluminum-based carrier, the preparation method of which is different from that of Example 1 only in that both aging and drying are one-stage instead of segmental aging and segmental drying. The aging condition is that the solution containing pseudo-boehmite is transferred to a water bath, and is aged at 60°C with a stirring rate of 100 rad / min for 3h; and the drying condition is that the washed pseudo-boehmite is placed in a 120°C air oven for drying for 20h, and is taken out and cooled, and is ground into a powder with a particle size of 200 mesh or less.

[0093] <Structure parameter test>

[0094] The BET specific surface area, pore volume, average pore diameter of the porous aluminum-based carrier of Example 1 to Example 5 and the aluminum-based carrier of Comparative Example 1 to Comparative Example 6 were measured by N2sorption-desorption method. See Table 1 for details.

[0095] Referring to Figure 3 , Figure 3 is the N2sorption curve of the porous aluminum-based carrier provided by Example 1 and the aluminum-based carrier provided by Comparative Example 2 and Comparative Example 6. It can be seen that the specific surface area and pore volume of Example 1 are 504 m 2 / g and 2.16 cm 3 / g, respectively, while the specific surface area and pore volume of Comparative Example 2 are 132 m 2 / g and 0.22 cm 3 / g, respectively, and the specific surface area and pore volume of Comparative Example 6 are 381 m 2 / g and 1.26 cm 3 / g, respectively.

[0096] Application Example 1

[0097] The application example 1 provides a CO2adsorbent, and the preparation method thereof comprises the following steps: 3g of polyethyleneimine is added into 45mL of methanol solution, stirred and dissolved to uniformly disperse the polyethyleneimine, 1g of the porous aluminum-based carrier of Example 1 is added, stirred and evaporated at 25°C for 4h, and then placed in a vacuum drying box and dried at 60°C for 6h to prepare a solid amine CO2adsorbent.

[0098] Application Example 2

[0099] The application example 2 provides a CO2adsorbent, and the preparation method thereof is different from that of application example 1 in that the amount of polyethyleneimine is 3.5g, and the porous aluminum-based carrier added is prepared from Example 2.

[0100] Application Example 3

[0101] The application example 3 provides a CO2adsorbent, and the preparation method thereof is different from that of application example 1 in that the amount of polyethyleneimine is 2.5g, and the porous aluminum-based carrier added is prepared from Example 3.

[0102] Application Example 4

[0103] The application example 4 provides a CO2adsorbent, and the preparation method thereof is different from that of application example 1 in that the porous aluminum-based carrier added is prepared from Example 4.

[0104] Application Example 5

[0105] The application example 5 provides a CO2adsorbent, and the preparation method thereof is different from that of application example 1 in that the amount of polyethyleneimine is 2.5g, and the porous aluminum-based carrier added is prepared from Example 5.

[0106] Comparative Application Examples 1 to 6 were prepared according to the preparation method of Application Example 1, using the aluminum-based supports of Comparative Examples 1 to 6, respectively.

[0107] <Adsorption performance test>

[0108] Test Example 1

[0109] 30 mg of Application Example 1 was placed in a crucible in a thermal analyzer, and the CO2 adsorbent was first pretreated under a nitrogen atmosphere at 120℃ for 30 min, then cooled to 90℃, and a CO2 gas with a flow rate of 50 mL / min and a concentration of 100 vol.% was introduced for the adsorption experiment, and the adsorption process was 60 min. Then the gas flow was switched to a nitrogen atmosphere, and the regeneration was carried out at 135℃ for 20 min, and then cooled to 90℃ for a new adsorption-regeneration process, and the adsorption-regeneration process was repeated for 30 times.

[0110] Test Example 2

[0111] According to the test conditions of Test Example 1, the adsorption performance test was carried out on Application Example 2, with the difference that the regeneration temperature was set to 120℃ and the regeneration time was set to 30 min.

[0112] Test Example 3

[0113] According to the test conditions of Test Example 1, the adsorption performance test was carried out on Application Example 3, with the difference that the adsorption temperature was set to 75℃, the regeneration temperature was set to 120℃, and the regeneration time was set to 30 min.

[0114] Test Example 4

[0115] According to the test conditions of Test Example 1, the adsorption performance test was carried out on Application Example 4, with the difference that the regeneration temperature was set to 110℃ and the regeneration time was set to 30 min.

[0116] Test Example 5

[0117] According to the test conditions of Test Example 1, the adsorption performance test was carried out on Application Example 5, with the difference that the concentration of the CO2 gas introduced during the adsorption experiment was set to 40 vol.%, the regeneration temperature was set to 110℃, and the regeneration time was set to 30 min.

[0118] According to the test method of Test Example 1, the adsorption performance test was carried out on Comparative Application Examples 1 to 6, respectively.

[0119] The products of the above examples and comparative examples were measured by using a specific surface area analyzer ASAP2460, and the test results are shown in Table 1.

[0120] Table 1 Structure and performance of porous aluminum-based supports in examples and comparative examples

[0121]

[0122] Table 2 Comparison of CO2 adsorption capacity in test examples

[0123]

[0124] Reference is made to Figure 4 , Figure 4 Figure 1 is a CO2 adsorption experiment graph of the solid amine adsorbent provided in Test Example One, Comparative Test Example Two and Comparative Test Example Six of the present application. As can be seen, the CO2 adsorption capacity of the solid amine adsorbent of Test Example One of the present application is about 214 mg / g, while the CO2 adsorption capacity of the solid amine adsorbent of Comparative Test Example Two is only 31 mg / g, and the CO2 adsorption capacity of the solid amine adsorbent of Comparative Test Example Six is 152 mg / g.

[0125] As shown in Table 1 and Figure 3 Table 2, the porous aluminum-based carrier prepared according to the preparation method of the present application has a large specific surface area, a large pore volume and a pore diameter, and when the porous aluminum-based carrier is used to prepare a CO2 adsorbent, the CO2 adsorption capacity of the CO2 adsorbent for CO2 can be improved. For example, the specific surface area of Example One can reach 504 m 2 / g, the pore volume can reach 2.16 cm 3 / g, and the average pore diameter can reach 15 nm. The CO2 adsorption capacity of the CO2 adsorbent prepared from the porous aluminum-based carrier of Example One can reach 214 mg / g. It is noted that the 10 min adsorption capacity of Example One can reach 205 mg / g, which shows that the CO2 adsorbent has a fast adsorption rate. For another example, the specific surface area of Example Four can reach 587 m 2 / g, the pore volume can reach 2.81 cm 3 / g, and the average pore diameter can reach 20 nm. The CO2 adsorption capacity of the CO2 adsorbent prepared from the porous aluminum-based carrier of Example Four can reach 226 mg / g, and the 10 min adsorption capacity can reach 215 mg / g.

[0126] Comparative Examples One to Six are the same as Example One except for the indicated differences. By comparing Comparative Examples One to Six with Example One, it can be found that:

[0127] Comparative Example One directly uses pseudo-boehmite which has not been aged and has not been washed with an organic solvent. The specific surface area of the pseudo-boehmite is 316 m 2 / g, the pore volume is 0.88 cm 3 / g, and the average pore diameter is 10 nm, which are all significantly smaller than those of Example One. The CO2 adsorbent prepared from the aluminum-based carrier of Comparative Example One has an adsorption capacity of 138 mg / g, which is far smaller than that of Example One.

[0128] Comparative Example 2 uses pseudo-boehmite which is not aged and directly washed by organic solvent, its specific surface area is 132 m 2 / g, pore volume is 0.22 cm 3 / g, average pore size is 5 nm, all of which are obviously smaller than Example 1, and far smaller than Comparative Example 1. The CO2 adsorbent prepared by the aluminum-based carrier in Comparative Example 2 has an adsorption capacity of 31 mg / g, far smaller than Example 1, and far smaller than Comparative Example 1.

[0129] Comparative Example 3 uses pseudo-boehmite which is aged but not washed by organic solvent, its specific surface area is 367 m 2 / g, pore volume is 0.83 cm 3 / g, average pore size is 8 nm, all of which are obviously smaller than Example 1, and close to the data of Comparative Example 1. The CO2 adsorbent prepared by the aluminum-based carrier in Comparative Example 3 has an adsorption capacity of 129 mg / g, far smaller than Example 1, close to Comparative Example 1, and far larger than Comparative Example 2.

[0130] Through the comparative analysis of Comparative Examples 1 to 3, it can be seen that the aging step and the organic solvent washing step have a strong correlation. Only the aluminum-based carrier material which is aged can achieve the purpose of pore expansion by organic solvent washing. If the aging step is not performed, the organic solvent washing cannot achieve the purpose of pore expansion, and on the contrary, the pore channels will collapse.

[0131] Comparative Example 4 uses pseudo-boehmite which is aged in one stage and dried in stages, its specific surface area is 422 m 2 / g, pore volume is 1.58 cm 3 / g, average pore size is 12 nm, all of which are smaller than Example 1. The CO2 adsorbent prepared by the aluminum-based carrier in Comparative Example 4 has an adsorption capacity of 169 mg / g, smaller than Example 1.

[0132] Comparative Example 5 uses pseudo-boehmite which is aged in stages and dried in one stage, its specific surface area is 406 m 2 / g, pore volume is 1.46 cm 3 / g, average pore size is 13 nm, all of which are smaller than Example 1. The CO2 adsorbent prepared by the aluminum-based carrier in Comparative Example 4 has an adsorption capacity of 169 mg / g, smaller than Example 1.

[0133] Comparative Example 6 uses pseudo-boehmite which is aged in one stage and dried in one stage, its specific surface area is 381 m 2 / g, pore volume is 1.26 cm 3The CO2 adsorbent prepared by the aluminum-based carrier in the comparative example six has an adsorption capacity of 152 mg / g, which is less than that of the example one and obviously less than that of the comparative examples four and five. It can be seen that the sectional aging and the sectional drying have a great influence on the specific surface area and volume of the pores.

[0134] The technical features of the above examples can be combined in any way. In order to make the description simple, all possible combinations of the technical features in the above examples are not described, however, as long as the combinations of the technical features do not contradict, they should be considered as the scope of the description.

[0135] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing a porous aluminum-based carrier, characterized in that, The preparation method includes the following steps: Segmented aging: The solution containing boehmite is aged in two segments. The first segment is aged by stirring at 50℃~80℃ with a stirring rate of 100rad / min~500rad / min and an aging time of 1h~5h. The second segment is aged by standing at 70℃~150℃ for 1h~8h. Organic solvent washing and pore enlargement: The precipitate in the solution containing boehmite is filtered out to obtain boehmite. The boehmite is first washed with water and then washed with an organic solvent. Segmented drying: The pseudoboehmite, after washing with organic solvent, is dried in segments. In the first segment, the organic solvent content in the pseudoboehmite is 15 wt.% to 60 wt.%, and it is dried at a low temperature of 50℃ to 90℃ with forced air drying, and the solvent evaporation rate is controlled at 1.5 wt.%·h. -1 ~4wt.%·h -1 In the second paragraph, the organic solvent content in the pseudoboehmite is less than 15 wt.%, and it is vacuum dried at 50℃ to 130℃, with the solvent evaporation rate controlled at 0.5 wt.%·h. -1 ~1.5wt.%·h -1 ; The porous aluminum-based carrier obtained has a pore volume greater than or equal to 2.0 cm³. 3 / g.

2. According to the preparation method of claim 1, when washing the pseudoboehmite with the organic solvent, the organic solvent and the pseudoboehmite are mixed evenly, stirred at 25℃~80℃ for 0.5h~3h at a stirring rate of 100rad / min~500rad / min, and then filtered. in, The washing is performed 1 to 5 times, and the mass ratio of the organic solvent to the boehmite added each time is 5:1 to 20:

1.

3. The preparation method according to claim 1, characterized in that, The organic solvent includes one or more of ethanol, acetic acid, propanol, acetone, glycerol, and butanol.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The dried boehmite was ground to a mesh size of less than 200.

5. A porous aluminum-based carrier, characterized in that, The porous aluminum-based carrier is prepared by the preparation method described in any one of claims 1 to 4.

6. A porous aluminum-based carrier as described in claim 5, characterized in that, The average pore size is 15nm to 20nm, and the specific surface area is greater than or equal to 480m². 2 / g.

7. A CO2 adsorbent, characterized in that, The CO2 adsorbent comprises the porous aluminum-based support as described in any one of claims 5 and 6, and the active substance supported on the porous aluminum-based support. The active substance is an amine, and the loading of the active substance in the CO2 adsorbent is 40% to 70%.

8. The application of the CO2 adsorbent as described in claim 7, characterized in that, The CO2 adsorbent is used for adsorbing carbon dioxide and / or desorbing and regenerating carbon dioxide after adsorption. Adsorption: CO2 is adsorbed in a CO2 gas stream of 4 vol.% to 100 vol.% at 60℃ to 100℃, wherein the CO2 adsorbent has a CO2 adsorption capacity greater than or equal to 200 mg / g; Desorption and regeneration: The CO2 adsorbent can be desorbed and regenerated under conditions of 100℃~150℃ in an inert gas or vacuum for 10min~50min.

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