Solid amine adsorbent, its preparation method and application

Abstract

Provided are a solid amine adsorbent, a method for preparing the same, and uses thereof. 【Solution means】The solid amine adsorbent includes a modified organic amine and a porous nanocarrier. The modified organic amine has a ratio of secondary amine of 70% or more. The method for preparing the modified organic amine includes the following process: S1: Mix and add an organic amine and an organic amine modifier to an acetonitrile solvent, and stir to mix well. S2: Add a crosslinking agent to the solution and stir. S3: While stirring, add acetic acid drop by drop to adjust the pH of the solution to neutral, and continue stirring. S4: Rotate and evaporate the above solution using a rotary evaporator at 90 - 110 °C until the solvent is completely evaporated, and use the obtained substrate as a modified organic amine. 【Effect】The modified solid amine adsorbent produced by the present invention can maintain high stability in repeated adsorption and desorption while considering the adsorption performance.

Description

Technical Field

[0001] The present invention relates to the technical field of solid amine adsorbents, and particularly relates to solid amine adsorbents, a preparation method thereof, and applications thereof.

Background Art

[0002] Currently, the increasing global CO2 emissions are further exacerbating the risks of climate change and threats to the ecological environment. Carbon dioxide capture, utilization, and storage (CCUS) have attracted wide attention among scientists as an important means to combat global climate change. Among them, CO2 capture is a pioneering and important technology that can effectively suppress CO2 emissions by recovering a large amount of CO2 generated from industries, power generation, etc. and efficiently separating and recovering it.

[0003] Solid amine CO2 adsorption technology has the characteristics of high-efficiency adsorption, low energy consumption, low cost, and a simple process, and is a carbon capture technology with broad application prospects. Among them, organic amines are components of solid amine adsorbents that directly react with CO2, and their properties critically determine the performance of the adsorbent. In the actual CO2 capture process, primary amine groups and secondary amine groups of organic amine molecules can react with CO2 in a molar ratio of 2:1 to form reversible amino carboxylic acids or carbamate products. After undergoing a temperature-programmed desorption reaction, the adsorbed CO2 can be separated, and the primary amine groups and secondary amine groups can be regenerated. To achieve CO2 concentration and efficient utilization of organic amines, the adsorbent requires a desorption reaction that uses pure CO2 as a purge gas under high-temperature environments. However, under high-temperature environments, due to poor thermal stability, organic amines volatilize from the surface of the adsorbent carrier, causing physical amine deactivation. Also, when pure CO2 is used as a purge gas, the CO2 adsorbed on the adsorbent becomes less likely to desorb from the adsorbent due to the influence of the concentration gradient. Instead, it further reacts to form irreversible compounds, resulting in the deactivation of amine groups on the organic amines and causing chemical deactivation of the adsorbent. Regarding the two serious problems faced by organic amines, physical deactivation and chemical deactivation, in order to promote the industrial application of solid amine adsorption, many scholars have conducted a lot of research to solve the problem of amine deactivation of the adsorbent. However, most of the research has led to a decrease in the adsorption performance of the adsorbent, with the single adsorption capacity decreasing by more than 50% at most. Most of the current research adopts means to improve the stability of adsorption at the expense of adsorption performance. Most of the current research uses means that sacrifice adsorption performance to improve stability, which is a major constraint for the actual industrial application process. Therefore, the preparation of solid amine adsorbents with excellent thermal and chemical stability, high adsorption performance, and a secondary amine ratio of more than 70% is a technical bottleneck that should be overcome to promote the industrial application of solid amine adsorbents.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention provides a solid amine adsorbent, a preparation method thereof, and an application, aiming at the drawbacks of the prior art.

Means for Solving the Problems

[0005] The present invention provides a solid amine adsorbent comprising a modified organic amine and a porous nanocarrier, wherein the loading amount of the modified organic amine in the adsorbent is 10 wt.% - 80 wt.%, the proportion of secondary amines in the modified organic amine is 70% or more, and the preparation method of the modified organic amine comprises the following steps. S1: Mix an organic amine and an organic amine modifier, add it to 5 - 15 times the volume fraction of an acetonitrile solvent, stir at 25 - 60 °C at 300 - 600 rpm for 3 - 5 minutes to mix uniformly. S2: Add a crosslinking agent to the solution and stir at room temperature for 5 - 20 hours at 300 - 1500 rpm. S3: While stirring at 300 - 600 rpm, add acetic acid dropwise to the solution to adjust the pH, keep it in the neutral range of pH 6.5 - 7.5, and continue stirring for 15 - 60 minutes. S4: Rotate and evaporate the above solution using a rotary evaporator at 90 - 110 °C until the solvent is completely evaporated, and use the obtained substrate as the modified organic amine.

[0006] Here, the organic amine modifier is selected from any one of acetaldehyde, propionaldehyde, cyclopentanone, cyclohexanone, acetone, 3 - pentanone, or cyclohexanone. The crosslinking agent is selected from any one of sodium triacetoxyborohydride ((CH3COO)3BHNa), sodium cyanoborohydride (NaBH3CN), or borane - 2 - methylpyridine complex (C6H 10 BN). The molar ratio of the organic amine to the organic amine modifier is 1:(1 - 4). The loading amount of the modified organic amine in the adsorbent is 10 wt.% - 80 wt.%.

[0007] The method for modifying the organic amine in the adsorbent is a method of reducing aldehyde or ketone with respect to the primary amine group of the organic amine and converting the primary amine into a secondary amine using a mild crosslinking agent. This method uses aldehyde or ketone as a modifier compared to highly reactive epoxy compounds, and realizes the graft modification of the organic amine using a mild crosslinking agent. It only converts the highly reactive primary amine into a secondary amine. Since the original secondary amine group has low activity and there is a certain steric site resistance effect in the carbon chain, the progress of the graft modification reaction is further restricted. Finally, by dropwise adding acetic acid during the reaction process, the pH of the reaction is controlled within a neutral range of 6.5 to 7.5, ensuring the conversion from primary amine to secondary amine, and at the same time, restricting the conversion from secondary amine to tertiary amine.

[0008] The modification reaction pathway is shown in Fig. 1. It targets chain organic amine molecules containing primary amine, secondary amine, and tertiary amine. Reaction (1) is the main reaction, reaction (2) hardly occurs, and the modification method is such that the primary amine conversion rate is 80% or more and the secondary amine conversion rate is 10% or less. The modification process of the organic amine is, firstly, to increase the molecular weight to improve the thermal stability and expand the application environment and application fields. Secondly, since the primary amine is converted into a secondary amine in the modification process, the proportion of the highly stable secondary amine in the organic amine molecule increases significantly, and the reaction occurs in the direction of desorption rather than in the direction of generating irreversible compounds in the CO2 desorption process. Finally, since the secondary amine hardly converts into a tertiary amine in the modification process, the decrease in the adsorption performance of the organic amine is extremely small. Ultimately, the amine efficiency can basically be maintained at a high level, which is of great significance in promoting the industrial application of CO2 recovery by solid amine adsorbents.

[0009] Furthermore, the organic amine is selected from any one of diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), or polyethyleneimine (PEI). Here, in order to keep the viscosity and amine density of the modified polyethyleneimine within the usable range, the polyethyleneimine is a branched or linear polymer with a weight average molecular weight of 300 to 2500, preferably a weight average molecular weight of 600 to 1200. Furthermore, the molar ratio of the organic amine to the crosslinking agent is 1:(1 - 4).

[0010] The present invention also provides the above method for preparing a solid amine adsorbent including the following steps. S1: Dissolve the evaporated modified organic amine using a base solution with a concentration of 0.5 - 3.0 mol / L, and extract 2 - 10 times using an extractant until the extraction is complete. S2: After mixing all the extraction phases, add a porous nanocarrier, and use a rotary evaporator to perform rotary evaporation at 40 - 140 °C until the solvent is completely evaporated to obtain Product 1. S3: Dry Product 1 in a vacuum drying oven at a temperature of 40 - 140 °C for 4 - 12 hours to obtain a solid amine adsorbent.

[0011] Furthermore, the alkaline solution is any one of sodium hydroxide, potassium hydroxide, barium hydroxide, or ammonia. Furthermore, the volume of the base solution is 1 - 3 times the volume fraction of acetonitrile. Furthermore, the extractant is any one of ethyl acetate, ethyl ether, diisopropyl ether, or isoamyl alcohol. Furthermore, the extractant is used once in an amount of 0.5 - 3 times the volume fraction of acetonitrile. Furthermore, the porous nanocarrier is any one of silica, alumina, zeolite molecular sieves, resin, or MOFs. The present invention also provides the application of the solid amine adsorbent in the field of CO2 adsorption.

Advantages of the Invention

[0012] In summary, the present invention achieves the following technical effects as compared with the prior art. (1) The solid amine adsorbent prepared according to the present invention can achieve high stability of organic amines in the desorption process while considering the stability of the adsorption capacity. (2) In the preparation methods of the present invention, the primary amine conversion rate is 80% or more and the secondary amine conversion rate is 10% or less in all cases. (3) The solid amine adsorbent prepared according to the present invention has a proportion of secondary amines in the modified organic amines of 70% or more and is excellent in stability. (4) The adsorption capacity of the solid amine adsorbent prepared according to the present invention remains stable even after 10 cycles.

Brief Description of the Drawings

[0013] To more clearly explain the technical solutions of the embodiments of the present invention, the attached drawings used in the embodiments are briefly introduced below. However, the following attached drawings only show specific embodiments of the present invention and should not be regarded as limiting the scope. It should be understood that those of ordinary skill in the art can obtain other related attached drawings based on these drawings without creative effort.

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0015] In order for those skilled in the art to better understand the embodiments of the present invention, hereinafter, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. However, it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments that can be obtained by those skilled in the art without creative labor should be included in the protection scope of the present invention.

[0016] I. Embodiments and Proportional Forms Raw Material Sources Propanetriol: CAS: 6-81-5, Shanghai LuoShi; B-PEI-300: CAS: 9002-98-6, Thermo Fisher Scientific Chemical; B-PEI-1200: CAS: 9002-98-6, Thermo Fisher Scientific Chemical; B-PEI-600: CAS: 9002-98-6, Thermo Fisher Scientific Chemical; B-PEI-1800: CAS: 9002-98-6, Thermo Fisher Scientific Chemical; TEPA: CAS: 112-57-2, Shanghai Aladdin; PEHA: CAS: 4067-16-7, Shanghai Aladdin; NaBH3CN: CAS: 25895-60-7, Shanghai Aladdin; (CH3COO)3BHNa: CAS: 56553-60-7, Vokai; Borane-2-methylpyridine complex (C6H 10 BN): CAS: 3999-38-0; Alfa Sodium hydroxide: CAS: 1310-73-2, Shanghai Aladdin; Acetonitrile: CAS: 75-05-8, Shanghai Aladdin; Diethyl ether: CAS: 2679-89-2, Shanghai Aladdin; Ethyl acetate: CAS: 141-78-6, Shanghai Aladdin; Acetone: CAS: 127-06-0, Shanghai Aladdin; Cyclopentanone: CAS: 120-92-3, Shanghai Aladdin; Cyclohexanone: CAS: 108-94-1, Shanghai Aladdin; Propylene oxide: CAS: 75-56-9, Vokai; Methanol: CAS: 67-56-1, Shanghai Aladdin.

[0017] II. Performance test methods (1) Cycle adsorption method of solid amine CO2 adsorbent Using a thermogravimetric analyzer, perform an adsorption test on 15 mg of the prepared adsorbent under the conditions of an adsorption temperature of 60°C, an atmosphere of CO2 concentration of 15%, an adsorption time of 60 minutes, a desorption temperature of 150°C, an atmosphere of CO2 concentration of 100%, and a desorption time of 30 minutes, and repeat the above adsorption and desorption conditions 10 times. (2) Test method for the ratio of primary, secondary, and tertiary amines of modified organic amines In this method, the ratio of primary, secondary, and tertiary amines of organic amine molecules is tested by a liquid 13C nuclear magnetic resonance apparatus (NMR; Bruker, Ascend TM500 MHz, Germany). The 13C spectrum is quantitatively analyzed by the inverse gated decoupling pulse method, and the distribution of primary, secondary, and tertiary amines is calculated by a quantitative method of area integration that examines the area of characteristic carbon atoms corresponding to primary, secondary, and tertiary amines. (3) Conversion rate test in organic amine modification Conversion rate from primary amine to secondary amine = (Ratio of primary amine before modification - Ratio of primary amine after modification) / Ratio of primary amine before modification Conversion rate from secondary amine to tertiary amine = (Ratio of tertiary amine after modification - Ratio of tertiary amine before modification) / Ratio of secondary amine before modification (4) CO2 Adsorption Test The CO2 adsorption characteristics of the adsorbent in this study were tested using a Setsys EVO Easy 1750 thermogravimetric analyzer (TGA; SETARAM, France). In the test, 15 - 25 mg of the adsorbent was weighed, and after degassing and stabilizing for 30 minutes at 150 °C in a 100% Ar atmosphere, the mass was taken as the initial mass M1. Then, the temperature and atmosphere were switched to 60 °C and 15% CO2, and after adsorbing for 60 minutes, the mass was taken as the saturated mass M2. The adsorption capacity Q (unit: mmol / g adsorbent) was calculated as follows.

[0018]

Equation

[0019] (Embodiment 1) The solid amine adsorbent obtained by the preparation of this embodiment includes an organic amine modification step and an adsorbent preparation step.

[0020] <Modification of Organic Amine> S1: Add 11.4 g of TEPA and 9.80 g of cyclohexanone (molar ratio 1.2:2) to 200 mL of an acetonitrile solvent, stir at 25 °C at 400 rpm for 3 minutes to form a homogeneous mixture. S2: Add 6.30 g of NaBH3CN (molar ratio 2:1 to TEPA) to this solution and stir at room temperature at 1000 rpm for 10 hours. S3: While stirring at 300 rpm, dropwise add acetic acid to adjust the pH of the solution to 7.0 and continue stirring for 30 minutes. S4: Rotate and evaporate the above solution using a vacuum rotary evaporator at 100 °C until the solvent is completely evaporated to obtain the modified organic amine.

[0021] <Preparation of Adsorbent> S5: Dissolve the evaporated modified organic amine in 200 mL of a 1.0 mol / L sodium hydroxide aqueous solution and extract it 4 times with 100 mL of ether each time. S6: Mix all the extracted phases, add 9.45 g of silica carrier, and rotary evaporate at 40 °C using a vacuum rotary evaporator until the solvent is completely evaporated to obtain Product 1. S7: Dry Product 1 in a vacuum drying oven at 40 °C for 6 hours to prepare a solid amine CO2 adsorbent with an organic amine loading of 50 wt%.

[0022] (Embodiment 2) The solid amine adsorbent obtained by the preparation of this embodiment includes an organic amine modification step and an adsorbent preparation step.

[0023] <Modification of Organic Amine> S1: Add 11.6 g of PEHA and 14.7 g of cyclopentanone (molar ratio 1:3.5) to 300 mL of acetonitrile solvent, stir at 35 °C and 500 rpm for 3 minutes to form a homogeneous mixture. S2: Add 9.45 g of NaBH3CN (molar ratio 3:1 with respect to PEHA) to this solution and stir at room temperature at 1000 rpm for 15 hours. S3: While stirring at 500 rpm, dropwise add acetic acid to adjust the pH of the solution to 7.0 to keep it neutral, and continue stirring for 30 minutes. S4: Rotary evaporate the above solution using a vacuum rotary evaporator at 100 °C until the solvent is completely evaporated to obtain the modified organic amine.

[0024] <Preparation of Adsorbent> S5: Dissolve the evaporated substrate in 300 mL of 1.5 mol / L sodium hydroxide aqueous solution and extract it three times with 200 mL of ethyl acetate each time. S6: Mix all the extracted phases, add an alumina carrier, and rotary evaporate at 85 °C using a vacuum rotary evaporator until the solvent is completely evaporated to obtain Product 1. S7: Dry Product 1 in a vacuum drying oven at 85 °C for 4 hours to prepare a solid amine CO2 adsorbent with an organic amine loading of 50 wt%.

[0025] In this embodiment, the ratio of primary amine, secondary amine, and tertiary amine of the modified organic amine was prepared as 4:80:16. However, as can be seen from FIG. 5 compared with the unmodified organic amine, the conversion rate of the primary amine to the secondary amine after modification was 89.7%, while the conversion rate of the secondary amine to the tertiary amine was only 4.3%. The prepared CO2 adsorbent had an adsorption capacity of 3.72 mmol / g for the first CO2 adsorption and 3.55 mmol / g for the tenth CO2 adsorption, and the adsorption residual rate was 95.4%. As a result, the modified organic amine and the prepared CO2 adsorbent exhibited excellent stability while considering the adsorption performance.

[0026] (Embodiment 3) The solid amine adsorbent obtained by the preparation of this embodiment includes an organic amine modification step and an adsorbent preparation step.

[0027] <Modification of Organic Amine> S1: 4.3 g of branched polyethyleneimine (B-PEI-1200) with a weight average molecular weight of 1200 and 8.7 g of acetone (molar ratio 1:1.5) are added to 100 mL of an acetonitrile solvent, and stirred at 50 °C and 500 rpm for 5 minutes to form a homogeneous mixture. S2: 9.45 g of NaBH3CN (molar ratio 1.5:1 with respect to polyethyleneimine) is added to this solution, and stirred at room temperature for 20 hours at 1000 rpm. S3: While stirring at 500 rpm, acetic acid is added dropwise to adjust the pH of the solution to 7.0, and stirring is continued for 30 minutes. S4: The above solution is rotary evaporated at 100 °C using a vacuum rotary evaporator until the solvent is completely evaporated to obtain a modified organic amine.

[0028] <Preparation of Adsorbent> S5: The evaporated substrate is dissolved in 200 mL of a 2.0 mol / L sodium hydroxide aqueous solution, and extracted 5 times with 50 mL of ether each time. S6: All the extraction phases are mixed, and a resin carrier is added using a vacuum evaporator at 45 °C until the solvent is completely evaporated to obtain a modified organic amine product. S7: The synthetic product prepared above is dried in a vacuum drying oven at 45 °C for 6 hours to prepare a solid amine CO2 adsorbent having a loading rate of 50 wt.% with respect to the organic amine.

[0029] (Embodiment 4) Although the masses of TEPA, cyclohexanone, and NaBH3CN used are 9.45 g, 14.7 g, and 9.45 g (molar ratio 1:3:3), the organic amine modifier and the adsorbent are prepared in the same manner as in Embodiment 1.

[0030] (Embodiment 5) Although the masses of PEHA, cyclopentanone, and NaBH3CN used are 11.6 g, 16.8 g, and 12.6 g (molar ratio 1:4:4), the organic amine modifier and the adsorbent are prepared in the same manner as in Embodiment 2.

[0031] (Embodiment 6) The organic amine modifier and the adsorbent are prepared in the same manner as in Embodiment 3, except that the masses of branched polyethyleneimine (B-PEI-1200) with a weight-average molecular weight of 1200, acetone, and NaBH3CN used are 4.3 g, 5.8 g, and 6.3 g (molar ratio 1:1:1).

[0032] (Embodiment 7) The organic amine modification and the adsorbent were prepared in the same manner as in Embodiment 3, except that the porous nanocarrier used was silica.

[0033] (Embodiment 8) The organic amine modification and the adsorbent are prepared in the same manner as in Embodiment 3, except that the porous nanocarrier used was alumina.

[0034] (Embodiment 9) The organic amine modification and the adsorbent are prepared in the same manner as in Embodiment 3, except that the porous nanocarrier used was zeolite molecular sieve.

[0035] (Embodiment 10) The modified organic amine and the adsorbent are prepared in the same manner as in Embodiment 6, except that the organic amine used was branched polyethyleneimine with a weight average molecular weight of 1800 (B-PEI-1800).

[0036] (Embodiment 11) The modified organic amine and the adsorbent are prepared in the same manner as in Embodiment 6, except that the organic amine used was branched polyethyleneimine with a weight average molecular weight of 600 (B-PEI-600).

[0037] (Embodiment 12) The modified organic amine and the adsorbent are prepared in the same manner as in Embodiment 6, except that the organic amine used was branched polyethyleneimine with a weight average molecular weight of 300 (B-PEI-300).

[0038] (Embodiment 13) The modified organic amine and the adsorbent are prepared in the same manner as in Embodiment 3, except that the crosslinking agent used was (CH3COO)3BHNa.

[0039] (Comparative Form 1) Comparative Form 1 directly prepares the adsorbent without performing the modification of the organic amine as compared with Embodiment 1. S1: After mixing 9.45 g of TEPA with 400 mL of ether, 9.45 g of silica carrier was added, and rotary evaporation was carried out at 45 °C using a vacuum rotary evaporator until the solvent was completely evaporated to obtain Product 1. S2: Product 1 was dried in a vacuum oven at 45 °C for 6 hours to prepare a solid amine CO2 adsorbent with an organic amine loading of 50 wt%.

[0040] (Comparative Form 2) Comparing Comparative Form 2 with Embodiment 2, the modification of the organic amine is not performed, and the adsorbent is directly prepared. S1: After mixing 11.6 g of PEHA with 600 mL of ethyl acetate, 11.6 g of alumina carrier was added, and rotary evaporation was carried out at 85 °C using a vacuum rotary evaporator until the solvent was completely evaporated to obtain Product 1. S2: Dry the product 1 in a vacuum oven at 85 °C for 4 hours to prepare a solid amine CO2 adsorbent with an organic amine loading of 50 wt%.

[0041] (Comparative Form 3) When comparing Comparative Form 3 with Embodiment 3, the adsorbent is prepared directly without modifying the organic amine. S1: After mixing 4.3 g of B-PEI-1200 with 250 mL of ether, add 4.3 g of the resin support and perform rotary evaporation using a vacuum rotary evaporator at 45 °C until the solvent is completely evaporated to obtain product 1. S2: Dry the product 1 in a vacuum oven at 45 °C for 6 hours to prepare a solid amine CO2 adsorbent with an organic amine loading of 50 wt%.

[0042] (Comparative Form 4) When comparing Embodiment 4 with Embodiment 3, the organic amine modifier was prepared in the same way as the adsorbent, but the difference is that 8.6 g of B-PEI-1200 was used with 2.32 g of acetone and 2.52 g of NaBH3CN (molar ratio 1:0.2:0.2).

[0043] (Comparative Form 5) When comparing Embodiment 5 with Embodiment 3, the preparation method of the adsorbent is the same, but the difference is that the pH of the reaction is controlled at 4 in step S3 of the organic amine modification.

[0044] (Comparative Form 6) When comparing Comparative Form 6 with Embodiment 1, the preparation method of the adsorbent is the same, but the difference is that the organic amine modification method used is the propylene oxide ring-opening grafting method. Propylene oxide and TEPA are mixed at a molar ratio of 2:1, added to methanol with a volume fraction 10 times, stirred at room temperature for 12 hours to obtain a methanol solution of the organic amine to be modified, add the silica support, perform rotary evaporation using a vacuum rotary evaporator at 70 °C until the solvent is completely evaporated, put the remaining substrate into a vacuum drying oven at 70 °C for 4 hours to prepare a solid amine CO2 adsorbent with 50 wt.% of the organic amine loaded.

[0045]

Table 1

[0046] In Embodiments 1 to 13, in all cases, an organic amine was modified, the conversion rate from primary amine to secondary amine in the organic amine was 85% or more, the conversion rate from secondary amine to tertiary amine was 7.3% or less, the proportion of secondary amine in the obtained modified organic amine was 70% or more, the solid amine adsorbent obtained with the modified organic amine had high stability, and the residual adsorption capacity was maintained at 93% or more even after 10 cycles. The fact that the adsorption capacity of the adsorbent is high means that the modified solid amine adsorbent obtained by the formulation and preparation method of the present application can improve the thermal stability and chemical stability while considering the adsorption performance. This shows that there are obvious advantages compared with the comparative form, and it can effectively satisfy the needs of customers and the market at a high level.

[0047] For Comparative Forms 1 to 3, none of them were modified. Since the solid amine adsorbent obtained from the unmodified organic amine has a high proportion of primary amines, the amine deactivation rate during the cycle process is high. The residual adsorption amount after 10 cycles remains in the range of 14.2% to 32.6%, indicating that the stability of the CO2 adsorbent prepared using the unmodified organic amine in the cycle adsorption process is not good. In the organic amine modification of Comparative Form 4, the amount of the added modifier was too small and the addition amount of the cross-linking agent was also insufficient. Therefore, the conversion from primary amine to secondary amine was incomplete, and the stability during the repeated adsorption and desorption of the prepared organic amine adsorbent was not good. The organic amine of Comparative Form 5 was modified under an acidic environment, so the conversion process from primary amine to secondary amine was inhibited, and the prepared organic amine and CO2 adsorbent were not stable. The modified organic amine of Comparative Form 6 was modified by ring-opening graft polymerization of propylene oxide. The initial adsorption capacity of the CO2 adsorbent prepared with the modified amine decreased by 25.1% compared with that of the unmodified Comparative Form 1, and the amine utilization efficiency was significantly reduced. However, since the initial adsorption capacity of the CO2 adsorbent prepared with the modified amine of Embodiment 1 of the present application changed little compared with that of the unmodified Comparative Form 1, this indicates that the adsorbent prepared using the modified organic amine of the present application can consider both stability and adsorption performance.

[0048] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any changes, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. CO ２ A method for preparing a solid amine adsorbent in the field of adsorption, characterized in that the solid amine adsorbent is composed of a modified organic amine and a porous nanocarrier, the proportion of secondary amine in the modified organic amine is 70% or more, and the loading amount of the modified organic amine in the solid amine adsorbent is 10 wt% to 80 wt%, and the preparation method for the modified organic amine comprises the following processes: S1: Mix an organic amine and an organic amine modifier, add to a 5-15-fold amount of acetonitrile solvent, and stir at 25-60°C and 300-600 rpm for 3-5 minutes to obtain a homogeneous mixture; S2: Add the crosslinker to the solution and stir at 300-1500 rpm for 5-20 hours at room temperature; S3: While stirring at 300-600 rpm, add acetic acid dropwise to the solution to adjust the pH to keep it in the neutral range of pH 6.5-7.5, and continue stirring for 15-60 minutes; S4: The solution is rotary evaporated using a rotary evaporator at 90 to 110° C. until the solvent is completely evaporated, and the obtained substrate is the modified organic amine; wherein the organic amine modifier is selected from any one of acetaldehyde, propionaldehyde, cyclopentanone, acetone, 3-pentanone, and cyclohexanone; the crosslinking agent is selected from any one of sodium triacetoxyborohydride, sodium cyanoborohydride, or borane-2-methylpyridine complex; the molar ratio of the organic amine to the organic amine modifier is 1:(1-4); The molar ratio of the organic amine to the crosslinking agent is 1:(1-4). ２ A method for producing solid amine sorbents in the adsorption field.

2. 2. The method of claim 1, wherein the organic amine is selected from any one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenepentamine, or polyethyleneimine.

3. 2. The method for preparing the solid amine sorbent according to claim 1, characterized in that the method for preparing the solid amine sorbent includes the following process: S1: The evaporated modified organic amine is dissolved using an alkaline solution with a concentration of 0.5-3.0 mol / L, and extracted with an extractant 2-10 times until the extraction is completed; S2: After mixing all the extraction phases, add the porous nanocarriers and rotatory evaporate at 40-140°C until the solvent is completely evaporated using a rotary evaporator to obtain product 1; S3: The product 1 is dried in a vacuum drying oven at a temperature of 40 to 140° C. for 4 to 12 hours to obtain a solid amine adsorbent.

4. 4. The method for producing a solid amine adsorbent according to claim 3, wherein the alkaline solution is any one of sodium hydroxide, potassium hydroxide, barium hydroxide, and ammonia.

5. 4. The method for preparing the solid amine adsorbent according to claim 3, wherein the volume of the alkaline solution is 1 to 3 times the volume of acetonitrile.

6. 4. The method of claim 3, wherein the extractant is one of ethyl acetate, ethyl ether, diisopropyl ether, or isoamyl alcohol.

7. 4. The method for preparing a solid amine sorbent according to claim 3, wherein the extractant is used in an amount of 0.5 to 3 times the volume of acetonitrile in one application.

8. 4. The method for producing a solid amine adsorbent according to claim 3, wherein the porous nanocarriers are any of silica, alumina, zeolite molecular sieves, resins or MOFs.

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