Carbon capture adsorbent with composite carrier loaded with organic amine as well as preparation method and application of carbon capture adsorbent

Abstract

The invention discloses a carbon capture adsorbent with a composite carrier loaded with organic amine as well as a preparation method and application thereof. The carbon capture adsorbent comprises the composite carrier and a modified active layer loaded on the surface of the composite carrier, the composite carrier comprises magnesium oxide and silicon oxide; and the modified active layer is a polydopamine-polyethyleneimine co-deposition layer. The adopted magnesium oxide has high specific surface area and chemical activity, the adopted silicon oxide has excellent thermal stability and structural stability, the magnesium oxide and the silicon oxide are compounded to prepare the carrier, guarantee can be provided for stable loading and efficient effects of functional groups, and the polydopamine has the characteristics of high biological adhesion and easy functionalization; the polyethyleneimine contains a large number of amino active sites, and the CO2 chemical adsorption capacity and hydrophobicity of the adsorbent can be synchronously enhanced through composite loading of the polyethyleneimine and the amino active sites. The technical bottlenecks that an existing adsorbent is poor in stability, insufficient in moisture resistance and limited in trapping efficiency are solved.

Description

Technical Field

[0001] This invention relates to the field of carbon capture technology, and more specifically, to a carbon capture adsorbent with organic amines supported on a composite carrier, its preparation method, and its application. Background Technology

[0002] With continuous technological advancements, the application scope of carbon capture technology is constantly expanding, from traditional fossil fuel power plants to emerging direct air capture systems, all contributing to the goal of achieving carbon neutrality.

[0003] Currently, CO2 capture technologies mainly include absorption, adsorption, and membrane separation. Among these, adsorption has broad prospects in industrial applications due to its advantages such as simple operation, low energy consumption, and reusable adsorbents. The adsorbent is the core of CO2 capture in adsorption methods, and its performance directly determines the capture efficiency and application cost. Existing CO2 adsorbents are mostly prepared by loading functional groups onto a single carrier. Single carriers often suffer from insufficient stability and poor dispersion of functional groups, making it difficult for the adsorbent's capture efficiency, mechanical strength, and heat resistance to meet the requirements of long-term industrial operation. Furthermore, industrial exhaust gases and flue gas from coal-fired power plants are often accompanied by a certain level of humidity. Traditional adsorbents are prone to active site failure and adsorption performance degradation in humid environments, severely limiting their industrial application.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a carbon capture adsorbent with organic amines supported on a composite carrier, along with its preparation method and applications. Magnesium oxide possesses a high specific surface area and chemical activity, while silicon oxide exhibits excellent thermal and structural stability. Combining these two components to prepare the carrier ensures stable loading and efficient functioning of functional groups. Polydopamine possesses strong bioadhesion and easy functionalization properties, while polyethyleneimine contains numerous amino active sites. The composite loading of these two components simultaneously enhances the adsorbent's CO2 chemisorption capacity and hydrophobicity. This overcomes the technical bottlenecks of existing adsorbents, such as poor stability, insufficient moisture resistance, and limited capture efficiency.

[0006] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a carbon capture adsorbent for organic amines supported on a composite carrier, comprising a composite carrier and a modified active layer supported on the surface of the composite carrier. The composite carrier comprises magnesium oxide and silicon oxide; The modified active layer is a polydopamine-polyethyleneimine co-deposited layer.

[0007] Furthermore, the mass ratio of MgO to SiO2 in the composite carrier is 1:2 to 1:5.

[0008] The proportion range selected in this invention allows the composite support to simultaneously possess suitable specific surface area and structural stability, providing sufficient loading sites for the modified active layer while ensuring the mechanical strength of the support. If the MgO proportion is too high, the heat resistance of the composite support will decrease; if the SiO2 proportion is too high, the number of adsorption active sites on the support will be reduced.

[0009] Furthermore, the loading of the modified active layer is 15% to 35% of the mass of the composite carrier. Too low a loading will result in insufficient CO2 capture capacity, while too high a loading will easily lead to aggregation of the active layer, reducing the capture kinetics performance.

[0010] Furthermore, the mass percentage of polyethyleneimine in the co-deposited layer is 30% to 60%, which can balance the number of amino active sites and the dispersion of the active layer, thereby maximizing the CO2 chemisorption capacity.

[0011] Secondly, the present invention provides a method for preparing a carbon trapping adsorbent with organic amines supported on a composite support, comprising the following steps: (1) Preparation of MgO-SiO2 composite carrier: MgO powder and SiO2 powder are mixed at a preset mass ratio, and dispersant and deionized water are added; the mixture is stirred evenly to form a suspension, which is then ultrasonically dispersed, dried, calcined at high temperature, and ground to obtain composite carrier powder; (2) The surface of the composite carrier is coated with a modified active layer: The composite carrier powder is added to the Tris buffer solution, and dopamine hydrochloride and polyethyleneimine are added at the same time. The mixture is stirred at 25~35℃ for 4~8h. After washing and drying, the PDA-PEI co-deposition modified composite carrier is obtained. (3) The modified composite support is calcined to obtain a high-efficiency carbon capture agent based on MgO-SiO2 composite support.

[0012] Furthermore, in step (1), the dispersant is selected as polyvinylpyrrolidone or polyethylene glycol, and the addition amount is 0.5%~2% of the total mass of MgO and SiO2, which can effectively prevent powder agglomeration and improve the uniformity of the carrier. The suspension is ultrasonically dispersed in an ultrasonic device for 30~60 min, and then dried at 80~120℃ for 4~8 h to remove moisture; the dried solid is placed in a muffle furnace and calcined at 500~700℃ for 2~4 h to fully fuse the two components. After cooling to room temperature, it is ground to obtain a composite carrier powder with uniform particle size.

[0013] Furthermore, in step (1), after obtaining the composite carrier powder, it undergoes surface pretreatment, specifically as follows: The prepared composite carrier powder was added to a dilute hydrochloric acid solution with a concentration of 0.1~0.5 mol / L, with a solid-liquid ratio of 1:15~1:25 (g / mL). The mixture was stirred at a constant temperature of 30~50℃ for 2~4 h. This pretreatment removed impurities from the carrier surface, increased surface active sites and roughness, and improved the bonding strength between the modified active layer and the carrier, preventing the active layer from falling off. After the pretreatment, the solid was collected by filtration and repeatedly washed with deionized water until the filtrate was neutral. The filtrate was then dried at 80~100℃ for 2~3 h to obtain the pre-modified composite carrier.

[0014] Further, in step (2), the concentration of dopamine hydrochloride is 0.5~2 mg / mL, and the concentration of polyethyleneimine is 1~3 mg / mL. The pre-modified composite carrier powder is added to a Tris buffer solution with a pH of 8.0~8.5 and a concentration of 50~100 mmol / L, and dopamine hydrochloride and PEI are added simultaneously, so that the concentration of dopamine hydrochloride is 0.5~2 mg / mL and the concentration of PEI is 1~3 mg / mL. The mixture is stirred at a constant temperature of 25~35℃ for 4~8 h to allow PDA and PEI to co-deposit on the surface of the pre-modified carrier to form an active layer. After the reaction is complete, the mixture is washed 3~4 times alternately with deionized water and ethanol to remove free components, and then dried to obtain the PDA-PEI co-deposited modified composite carrier.

[0015] Furthermore, in step (4), the calcination temperature is 300~400℃ and the calcination time is 4~6h.

[0016] Thirdly, this invention provides the application of a carbon capture adsorbent in CO2 capture. The carbon capture adsorbent is filled into an adsorption column, allowing a CO2-containing gas mixture to pass through the column at a flow rate of 0.5–2 L / min. High-efficiency CO2 capture is achieved under conditions of 25–80°C and 30%–80% relative humidity. Once the adsorbent reaches saturation, desorption can be performed at 120–150°C to decompose the products, release CO2, and recover the adsorbent. The adsorbent can be reused multiple times, reducing operating costs.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention provides a carbon capture adsorbent loaded with organic amines on a composite carrier, its preparation method and application. The composite carrier is prepared by using MgO and SiO2, which fully utilizes the advantages of MgO's large specific surface area and high adsorption activity and SiO2's strong thermal stability and stable structure. This effectively improves the mechanical strength and heat resistance of the carbon capture agent, making it adaptable to complex working conditions of high temperature and high flow rate in industry and extending the service life of the adsorbent. 2. The present invention provides a carbon capture adsorbent with organic amines loaded on a composite carrier, its preparation method, and its application. Through pre-modification of the carrier surface, the surface activity and roughness of the carrier are significantly improved, enhancing the bonding strength between the subsequent PDA / PEI modified active layer and the carrier, effectively preventing the active components from falling off, and providing more sites for loading the active layer. Combined with PDA coating or PDA-PEI co-deposition modification, a large number of amino active sites are directionally introduced to enhance CO2 chemical adsorption, and the hydrophobic properties of PDA are used to improve the moisture resistance, making it suitable for actual industrial flue gas humid conditions. 3. The present invention provides a carbon capture adsorbent with organic amines loaded on a composite carrier, a preparation method and application. The preparation process is mild and easy to control, does not require high temperature and high pressure equipment, the overall preparation process is simple, the raw materials are readily available and the cost is controllable, the adsorbent can be repeatedly regenerated and reused, the energy consumption is low, there is no secondary pollution, it is suitable for industrial-scale production and application, and is of great significance for mitigating the greenhouse effect and promoting the development of the environmental protection industry. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. The illustrative embodiments and descriptions of this invention are only used to explain this invention and are not intended to limit this invention.

[0019] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known methods have not been specifically described in order to avoid obscuring the invention.

[0020] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination.

[0021] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0022] Example 1 This embodiment provides a method for preparing a highly efficient carbon capture agent based on a MgO-SiO2 composite support, comprising the following steps: (1) Preparation of MgO-SiO2 composite carrier: Weigh 10g of MgO powder and 20g of SiO2 powder, mix them evenly, add 0.3g of polyethylene glycol and 180mL of deionized water, stir for 20min to form a suspension; ultrasonically disperse the suspension for 30min, and then dry it at 80℃ for 8h; place the dried solid in a muffle furnace, calcine at 500℃ for 4h, cool to room temperature and grind to obtain composite carrier powder.

[0023] (2) Surface pre-modification of composite carrier: Weigh 10g of composite carrier powder and add it to 150mL of KH550 silane coupling agent ethanol pretreatment solution with a concentration of 2% (volume fraction). Stir at 35℃ for 2.5h. After the reaction is completed, filter, wash with deionized water until neutral, and dry at 85℃ for 3h to obtain pre-modified composite carrier.

[0024] (3) Construction of PDA-PEI co-deposition layer: Weigh 10g of pre-modified composite carrier powder, add it to 120mL of Tris buffer solution with pH=8.0 and concentration of 50mmol / L, add 0.1g of dopamine hydrochloride and 0.2g of PEI, and stir at 25℃ for 6h. After the reaction is completed, wash with deionized water and ethanol alternately 4 times, and dry at 60℃ for 6h to obtain PDA-PEI co-deposition modified composite carrier (PEI accounts for 40% of the mass in the co-deposition layer).

[0025] (4) Preparation of finished product: The modified composite carrier is placed in a muffle furnace and calcined at 350°C for 6 hours to obtain carbon capture agent (the co-deposited layer loading is 18% of the composite carrier mass).

[0026] Example 2 This embodiment provides a method for preparing a high-efficiency carbon capture agent based on a MgO-SiO2 composite support, comprising the following steps: (1) Preparation of MgO-SiO2 composite carrier: Weigh 10g of MgO powder and 50g of SiO2 powder, mix them evenly, add 1.2g of polyvinylpyrrolidone and 250mL of deionized water, stir for 40min to form a suspension; ultrasonically disperse the suspension for 60min, and then dry it at 120℃ for 4h; place the dried solid in a muffle furnace, calcine at 700℃ for 2h, cool to room temperature and grind to obtain composite carrier powder.

[0027] (2) Surface pre-modification of composite carrier: Weigh 10g of composite carrier powder and add it to 200mL of dilute hydrochloric acid pretreatment solution with a concentration of 0.4mol / L. Stir at 45℃ for 2h. After the reaction is completed, filter and wash with deionized water until the filtrate is neutral. Dry at 100℃ for 2h to obtain pre-modified composite carrier.

[0028] (3) Construction of PDA-PEI co-deposition layer: Weigh 10g of pre-modified composite carrier powder, add it to 180mL of Tris buffer solution with pH=8.3 and concentration of 100mmol / L, add 0.2g of dopamine hydrochloride and 0.3g of PEI, and stir at 35℃ for 4h. After the reaction is completed, wash with deionized water and ethanol three times alternately, and dry at 80℃ for 4h to obtain PDA-PEI co-deposition modified composite carrier (PEI accounts for 50% of the mass in the co-deposition layer).

[0029] (4) Preparation of finished product: The modified composite carrier is placed in a muffle furnace and calcined at 400°C for 4 hours to obtain carbon capture agent (the co-deposited layer loading is 32% of the composite carrier mass).

[0030] Comparative Example 1 This comparative example provides a method for preparing a carbon capture adsorbent, which differs from Example 2 in that it uses a single SiO2 powder as a carrier to load PDA and PEI.

[0031] Comparative Example 2 This comparative example provides a method for preparing a carbon capture adsorbent, which differs from Example 2 in that only PDA is loaded on the surface of the composite carrier.

[0032] Comparative Example 3 This comparative example provides a method for preparing a carbon trapping adsorbent, which differs from Example 2 in that: ethylenediamine is loaded onto a single SiO2 surface.

[0033] Performance testing The carbon capture adsorbents prepared in Examples 1-2 and Comparative Examples 1-3 were subjected to performance tests under the following conditions: adsorption temperature 50℃, CO2 gas flow rate 1L / min, CO2 volume fraction 15%, and relative humidity 60% (simulating humid industrial conditions). The test results are shown in Table 1 below. Table 1 The test results show that the carbon capture adsorbents prepared in Examples 1 and 2 of this invention are significantly better than those prepared in Comparative Examples 1-3 in terms of CO2 adsorption capacity, heat resistance, reusability, and moisture resistance. Among them, Example 2 has the best performance due to the use of high-loading PDA-PEI co-deposition modification and the strengthening of the active layer binding force after pre-modification treatment. It not only has a higher adsorption capacity, but also a better activity retention rate after repeated use. It can effectively adapt to industrial humid conditions and has good industrial application potential.

[0034] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A carbon capture adsorbent for organic amines supported on a composite carrier, characterized in that, It comprises a composite carrier and a modified active layer loaded on the surface of the composite carrier; The composite carrier comprises magnesium oxide and silicon oxide; The modified active layer is a polydopamine-polyethyleneimine co-deposited layer.

2. The carbon capture adsorbent for organic amines supported on a composite carrier according to claim 1, characterized in that, The mass ratio of MgO to SiO2 in the composite carrier is 1:2 to 1:

5.

3. The carbon capture adsorbent for organic amines supported on a composite carrier according to claim 1, characterized in that, The loading amount of the modified active layer is 15% to 35% of the mass of the composite carrier.

4. The carbon capture adsorbent for organic amines supported on a composite carrier according to claim 3, characterized in that, Polyethyleneimine accounts for 30% to 60% of the mass of the co-deposited layer.

5. A method for preparing a carbon capture adsorbent with organic amine supported on a composite carrier as described in any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Preparation of MgO-SiO2 composite carrier: MgO powder and SiO2 powder are mixed according to a preset mass ratio, dispersant and deionized water are added, and the mixture is stirred evenly to form a suspension. After ultrasonic dispersion, drying and high-temperature calcination, the composite carrier powder is obtained by grinding. (2) The surface of the composite carrier is coated with a modified active layer: The composite carrier powder is added to the Tris buffer solution, and dopamine hydrochloride and polyethyleneimine are added at the same time. The mixture is stirred at 25~35℃ for 4~8h. After washing and drying, the PDA-PEI co-deposition modified composite carrier is obtained. (3) The modified composite support is calcined to obtain a high-efficiency carbon capture agent based on MgO-SiO2 composite support.

6. The method for preparing a carbon trapping adsorbent with organic amine supported on a composite carrier according to claim 5, characterized in that, In step (1), the dispersant is usually polyvinylpyrrolidone or polyethylene glycol, and the amount added is 0.5% to 2% of the total mass of MgO and SiO2; the high-temperature calcination temperature is 500 to 700°C, and the calcination time is 2 to 4 hours.

7. The method for preparing a carbon trapping adsorbent with organic amine supported on a composite carrier according to claim 5, characterized in that, In step (1), after obtaining the composite carrier powder, it undergoes surface pretreatment, specifically as follows: The prepared composite carrier powder was added to a dilute hydrochloric acid solution and stirred at a constant temperature of 30-50℃ for 2-4 hours. Then, it was filtered, washed with deionized water until neutral, and dried at 80-100℃ for 2-3 hours to obtain the pretreated composite carrier. The concentration of the dilute hydrochloric acid solution was 0.1-0.5 mol / L.

8. The method for preparing a carbon trapping adsorbent with organic amine supported on a composite carrier according to claim 5, characterized in that, In step (2), the concentration of dopamine hydrochloride is 0.5~2 mg / mL and the concentration of polyethyleneimine is 1~3 mg / mL.

9. The method for preparing a carbon trapping adsorbent with organic amine supported on a composite carrier according to claim 5, characterized in that, In step (4), the calcination temperature is 300~400℃ and the calcination time is 4~6h.

10. The application of the carbon capture adsorbent according to any one of claims 1 to 4 in CO2 capture, characterized in that, The carbon capture agent is filled into an adsorption column, and a gas mixture containing CO2 is passed through the adsorption column at a flow rate of 0.5~2L / min to achieve efficient CO2 capture under conditions of 25~80℃ and 30%~80% relative humidity.

Images