A quaternary ammonium modified polyurethane CO2 adsorbent and its preparation method

Abstract

The present invention discloses a quaternary ammonium-modified polyurethane CO2 adsorbent and a preparation method thereof. The quaternary ammonium-modified polyurethane CO2 adsorbent comprises: a polyurethane porous carrier, and functional ions loaded therein. The preparation method comprises: subjecting the polyurethane to a hydrophilic modification treatment, then contacting the hydrophilic polyurethane with a functional quaternary ammonium mixed solution, soaking and heating, then filtering and washing, and subjecting the obtained material to ion exchange to obtain the quaternary ammonium-modified polyurethane CO2 adsorbent. The polyurethane CO2 adsorbent prepared by the present invention is granular and is more convenient for practical engineering applications compared to existing powdered CO2 adsorbents. At the same time, the adsorbent has a higher CO2 adsorption performance, which can reach 1.80 mmol / g, and still has a high adsorption capacity after 10 adsorption and desorption cycles, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide adsorption, and in particular to a quaternary ammonium group-modified polyurethane CO2 adsorbent and a preparation method thereof. Background Art

[0002] Currently, carbon dioxide, the primary driver of global warming, is emitted not only from centralized sources like power plants and steel mills, but also from mobile, decentralized sources like exhaust from cars and airplanes. Carbon capture, utilization, and storage (CCUS) and direct air capture (DAT) are important tools for addressing this issue. DAT not only captures CO2 from mobile, decentralized sources, but also captures CO2 leaked during the storage process. This makes it an important complement to CCUS for centralized sources, jointly achieving carbon reduction targets.

[0003] Carbon dioxide adsorbents are at the heart of direct air capture technology. Nanoporous materials loaded with carbonate ions can serve as adsorbents for both adsorption and desorption of carbon dioxide. The basic principle is that when dry, the material adsorbs CO2. When the ambient humidity increases, the material desorbs CO2, enabling an adsorption / desorption cycle by adjusting the humidity.

[0004] As shown in chemical reaction equations (1) and (2), as the number of water molecules decreases, the free energy of carbonate ion hydrolysis becomes negative, and there is a trend of spontaneous reaction in thermodynamics, that is, it can be self-hydrolyzed into bicarbonate ions and hydroxide ions, and the OH produced - It has a strong adsorption capacity for acidic CO2. When the humidity increases, the number of water molecules increases and CO2 is released.

[0005]

[0006] Current variable-wetting adsorbents mainly include ion exchange resin powder, chitosan aerogel powder, and quaternized bamboo cellulose powder. However, since powder materials are not suitable for large-scale engineering applications, they are currently only in the laboratory research stage. Some scholars combine ion exchange resin powder with materials such as polyvinyl chloride to make ion exchange membranes to adsorb carbon dioxide. However, because the base material is inert and cannot adsorb carbon dioxide, the CO2 adsorption capacity of the ion exchange membrane is not strong. At the same time, in order to adapt to engineering application scenarios, the flat ion exchange membrane needs to be processed into a three-dimensional porous shape to achieve the maximum possible filling of the adsorption tower with adsorbent and maximize the contact area between the ion exchange membrane and the air. This step consumes a lot of manpower and material resources. Summary of the Invention

[0007] To overcome the aforementioned problems of the prior art, the present invention provides a quaternary ammonium-modified polyurethane CO2 adsorbent and a method for its preparation. The preparation method of the present invention features low energy consumption, a simple process, and is economical and environmentally friendly. The prepared polyurethane CO2 adsorbent is granular, making it more suitable for practical engineering applications compared to existing powdered CO2 adsorbents. Furthermore, the adsorbent lacks an inert base material, exhibits enhanced CO2 adsorption performance, and has promising prospects for engineering applications.

[0008] The present invention provides a method for preparing a quaternary ammonium group-modified polyurethane CO2 adsorbent, comprising the following steps:

[0009] a) mixing the isocyanate and the composite polyether at room temperature, and rapidly stirring to obtain a first reaction product;

[0010] b) rinsing the first reaction product obtained in step a) with water, drying it, and then cleaning it in an ultrasonic cleaner with acetone, anhydrous ethanol, and deionized water for 10 to 20 minutes, respectively. Then, soaking it in an oxidizing solution, washing it with water, and drying it for later use. The chemically oxidized polyurethane is soaked in a glutaraldehyde solution for 24 hours, and then soaked in an acrylic acid solution at a certain temperature to carry out a grafting reaction. After completion, it is washed with ethanol to obtain a second reaction product.

[0011] c) soaking the second reaction product obtained in step b) in a NaOH aqueous solution at room temperature for 2 to 6 hours to enhance reactivity, washing with water and drying at 60 to 70° C., first adding isopropyl alcohol and 3-chloro-2-hydroxypropyltrimethylammonium chloride, and then adding a NaOH aqueous solution to carry out a quaternization reaction, and the obtained product is washed with an HCl aqueous solution and then with water until the pH of the washing solution reaches neutral, thereby obtaining a third reaction product;

[0012] d) After filtering the third reaction product obtained in step c), adding Na2CO3 solution to carry out several ion exchange reactions, and finally washing with water, filtering and drying to obtain a granular quaternary ammonium group-modified polyurethane CO2 adsorbent.

[0013] The chemical reactions of the preparation process are as follows:

[0014]

[0015] Preferably, the mass ratio of the isocyanate to the combined polyether in step a) is 1:(1-2).

[0016] Preferably, the oxidation solution in step b) is a mixed solution of 0.7% (mass fraction) nitric acid and 17% (mass fraction) sulfuric acid in a mass ratio of 1:1 to 3; and the soaking time is 6 to 8 hours.

[0017] Preferably, the molar concentration of acrylic acid in step b) is 1.0 to 3.5 mol / L; the time of the grafting reaction is 1.0 to 2.5 hours; and the temperature of the grafting reaction is 15 to 45°C.

[0018] Preferably, the mass fraction of the NaOH aqueous solution in step c) is 20-40%.

[0019] Preferably, the amount of isopropanol used in step c) is 20-40 mL of isopropanol for every 1 g of the second reaction product; the mass fraction of the 3-chloro-2-hydroxypropyl-trimethylammonium chloride is 60%, and the amount used is 3-5 mL of 3-chloro-2-hydroxypropyl-trimethylammonium chloride for every 1 g of the second reaction product; the volume ratio of the NaOH aqueous solution to the 3-chloro-2-hydroxypropyl-trimethylammonium chloride solution is (3-5):5.

[0020] Preferably, the quaternization reaction temperature in step c) is 25-40° C., and the reaction time is 3-5 h.

[0021] Preferably, the molar concentration of the HCl aqueous solution in step c) is 0.1 mol / L.

[0022] Preferably, the process of the several ion exchange reactions in step d) is specifically as follows:

[0023] The third reaction product obtained in step c) is added with 0.4-0.6 mol / L Na2CO3 solution and stirred for 2-6 hours, then filtered, washed with water, and filtered again to complete an ion exchange; the above ion exchange is repeated 3-5 times.

[0024] The present invention also provides a quaternary ammonium group-modified polyurethane CO2 adsorbent, which is prepared by the preparation method described in the above technical solution and is in granular form, comprising a polyurethane porous carrier and functional ions loaded therein.

[0025] The present invention also provides a method for direct air capture of carbon dioxide, using the quaternary ammonium modified polyurethane CO2 adsorbent described in the above technical solution for the adsorption and desorption of carbon dioxide, and the quaternary ammonium modified polyurethane CO2 adsorbent has an adsorption capacity of 1.40 to 1.80 mmol / g for CO2.

[0026] Compared to existing technologies, the preparation method provided by the present invention uses polyurethane as the raw material and, under specific process steps and conditions, achieves optimal interaction, thereby producing a quaternary ammonium-modified polyurethane CO2 adsorbent. This quaternary ammonium-modified polyurethane CO2 adsorbent expands the application range of polyurethane and provides more options for the selection of wet-regeneration capture materials for carbon dioxide, while also exhibiting high carbon dioxide adsorption performance. Experimental results show that the quaternary ammonium-modified polyurethane CO2 adsorbent provided by the present invention has a CO2 adsorption capacity of 1.40 to 1.80 mmol / g.

[0027] At the same time, the raw materials selected and the preparation method provided by the present invention have the advantages of low energy consumption cost, simple process, economy and environmental protection, and therefore have good application prospects in the field of CO2 direct air capture technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a flow chart of the preparation method of the present invention.

[0029] Figure 2 This is an infrared test image of a quaternary ammonium group-modified polyurethane CO2 adsorbent of the present invention;

[0030] Figure 3 This is a scanning electron microscope image of a quaternary ammonium group-modified polyurethane CO2 adsorbent of the present invention;

[0031] Figure 4 The adsorption curves of an embodiment and a comparative example of a quaternary ammonium group-modified polyurethane CO2 adsorbent of the present invention are shown;

[0032] Figure 5 This is a physical picture of a quaternary ammonium group-modified polyurethane CO2 adsorbent of the present invention;

[0033] Figure 6 This is a physical picture of a quaternary ammonium-modified polyurethane CO2 adsorbent of the present invention placed in a small adsorption tower. DETAILED DESCRIPTION

[0034] In order to make the technical content, achieved objectives, effects and advantages of the present invention more clear, the following description is given in conjunction with the embodiments and the accompanying drawings.

[0035] like Figure 1 As shown, the present invention provides a method for preparing a quaternary ammonium group-modified polyurethane CO2 adsorbent, comprising the following steps:

[0036] a) mixing the isocyanate and the composite polyether at room temperature, and rapidly stirring to obtain a first reaction product;

[0037] b) rinsing the first reaction product obtained in step a) with water, drying it, and then cleaning it in an ultrasonic cleaner with acetone, anhydrous ethanol, and deionized water for 10 to 20 minutes, respectively. Then, soaking it in an oxidizing solution, washing it with water, and drying it for later use. The chemically oxidized polyurethane is soaked in a glutaraldehyde solution for 24 hours, and then soaked in an acrylic acid solution at a certain temperature to carry out a grafting reaction. After completion, it is washed with ethanol to obtain a second reaction product.

[0038] c) soaking the second reaction product obtained in step b) in a NaOH aqueous solution at room temperature for 2 to 6 hours to enhance reactivity, filtering, washing with water, and drying at 60 to 70° C., first adding isopropyl alcohol and 3-chloro-2-hydroxypropyltrimethylammonium chloride, then adding a NaOH aqueous solution, and then maintaining the temperature at 40° C. for quaternization reaction, and washing the obtained product with an HCl aqueous solution and then water in sequence until the pH of the washing solution reaches neutral, thereby obtaining a third reaction product;

[0039] d) filtering the third reaction product obtained in step c), adding a Na2CO3 solution to carry out several ion exchange reactions, and finally washing with water, filtering and drying to obtain a quaternary ammonium group-modified polyurethane CO2 adsorbent.

[0040] The present invention first mixes an isocyanate and a composite polyether at room temperature and then rapidly stirs to obtain a first reaction product. In the present invention, the mass ratio of the isocyanate to the composite polyether is preferably 1:(1-2), more preferably 1:1. The present invention does not particularly limit the source of the polyurethane black and white material; commercially available products or homemade products familiar to those skilled in the art can be used.

[0041] After obtaining the first reaction product, the present invention rinses the obtained first reaction product with water, dries it, and sequentially cleans it with acetone, anhydrous ethanol, and deionized water in an ultrasonic cleaner for 10 to 20 minutes, then soaks it in an oxidizing solution, washes it with water, and then dries it for later use. The chemically oxidized polyurethane is soaked in a glutaraldehyde solution for 24 hours, and then soaked in an acrylic acid solution at a certain temperature to carry out a grafting reaction. After completion, it is washed with ethanol to obtain a second reaction product.

[0042] The present invention has no particular limitation on the sources of acetone, anhydrous ethanol, aqueous nitric acid solution, aqueous concentrated sulfuric acid solution, glutaraldehyde and acrylic acid solution, and commercially available products known to those skilled in the art may be used.

[0043] In the present invention, the oxidizing solution is a mixed solution of 0.7% (mass fraction) nitric acid and 17% (mass fraction) sulfuric acid in a mass ratio of 1:(1-3), preferably 1:1. In the present invention, the soaking time is 6-8 hours, preferably 8 hours of soaking reaction at 25°C. In the present invention, the molar concentration of acrylic acid is preferably 1.0-3.5 mol / L, more preferably 3.5 mol / L. In the present invention, the time of the grafting reaction is preferably 1.0-2.5 hours, more preferably 1.5 hours. In the present invention, the temperature of the grafting reaction is preferably 15-45°C, more preferably 40°C.

[0044] The product is washed with anhydrous ethanol to obtain a second reaction product.

[0045] After obtaining the second reaction product, the present invention soaks the obtained second reaction product in a NaOH aqueous solution at room temperature for 2 to 6 hours to enhance reactivity, washes with water, and then dries at 60 to 70° C., first adds isopropyl alcohol and 3-chloro-2-hydroxypropyltrimethylammonium chloride, then adds a NaOH aqueous solution, and then performs a quaternization reaction. The obtained product is washed with an HCl aqueous solution and then water in sequence until the pH of the washing solution reaches neutral, thereby obtaining a third reaction product.

[0046] The present invention has no particular limitation on the sources of the NaOH aqueous solution, isopropyl alcohol, 3-chloro-2-hydroxypropyltrimethylammonium chloride and HCl aqueous solution, and commercially available products known to those skilled in the art may be used.

[0047] In the present invention, the mass fraction of the NaOH aqueous solution is preferably 20-40%, more preferably 30%. In the present invention, the amount of isopropyl alcohol is preferably 20-40 mL of isopropyl alcohol per 1 g of the second reaction product, more preferably 30 mL. In the present invention, the mass fraction of the 3-chloro-2-hydroxypropyl-trimethylammonium chloride is preferably 60%, and the amount is preferably 3-5 mL of 3-chloro-2-hydroxypropyl-trimethylammonium chloride per 1 g of the second reaction product, more preferably 5 mL. In the present invention, the volume ratio of the NaOH aqueous solution to the 3-chloro-2-hydroxypropyl-trimethylammonium chloride solution is preferably (3-5):5, more preferably 4:5.

[0048] The present invention is carried out at 25-40° C. for 3-5 hours, preferably at 40° C. for 4 hours.

[0049] In the present invention, the washing process is preferably as follows: washing the filtered product with water for the first time, washing with a 0.1 mol / L hydrochloric acid aqueous solution, and washing with water for the second time until neutrality to obtain a third reaction product.

[0050] After obtaining the third reaction product, the present invention filters the third reaction product and then adds a Na2CO3 solution to conduct several ion exchange reactions. Finally, the product is washed with water, filtered, and dried to obtain a quaternary ammonium group-modified polyurethane CO2 adsorbent. The present invention does not particularly limit the source of the Na2CO3 solution; commercially available products or homemade products known to those skilled in the art can be used.

[0051] In the present invention, the process of the multiple ion exchange reactions is preferably as follows:

[0052] The washed and filtered third reaction product was added with 0.5 mol / L Na2CO3 solution and stirred for 4 h, then filtered, washed with water, and filtered again to complete an ion exchange; the above ion exchange was repeated 4 times.

[0053] The present invention has no special limitation on the washing and filtering process, and a large amount of deionized water well known to those skilled in the art can be used for washing and filtering.

[0054] The quaternary ammonium modified polyurethane CO2 adsorbent prepared by the preparation method provided by the present invention is further subjected to quaternary ammonium treatment after hydrophilic modification and grafting of hydroxyl groups on the polyurethane. Figure 2 It can be seen from the infrared test chart that at 1450~1600cm -1 In the range, two obvious characteristic peaks appeared, namely 1465cm -1 and 1565cm -1 , namely CH bending vibration and CN stretching vibration, which indicates that the quaternary ammonium group has been loaded on the polyurethane. Compared with the traditional quaternary ammonium anion exchange resin CO2 adsorbent, it improves the carbon dioxide adsorption performance, reduces the cost, helps to achieve carbon emission reduction, and is in line with the concept of sustainable development. At the same time, Figure 5 As shown, the polyurethane CO2 adsorbent prepared by the present invention is in granular form, which is more convenient for practical engineering applications compared with existing powdered CO2 adsorbents.

[0055] The present invention also provides a quaternary ammonium modified polyurethane CO2 adsorbent, which is prepared by the preparation method described in the above technical solution. The preparation method provided by the present invention uses polyurethane as raw material, and achieves good interaction under specific process steps, condition and parameters, thereby preparing a quaternary ammonium modified polyurethane CO2 adsorbent; the carbon dioxide adsorption capacity of ordinary resin or anion exchange resin membrane is 0.4-0.8mmol / g, and the carbon dioxide adsorption capacity of quaternized chitosan aerogel and quaternized bamboo cellulose is about 0.18mmol / g. The carbon dioxide of the quaternary ammonium modified polyurethane CO2 adsorbent provided by the present invention is placed in Figure 6 The adsorption capacity of the small adsorption tower shown can reach 1.40~1.80mmol / g. Figure 4 It can be seen from the adsorption curve that the adsorption capacity of the CO2 adsorbents in the examples is within this range. Therefore, it can be shown that under the same quality, the quaternary ammonium modified polyurethane CO2 adsorbent provided by the present invention has better carbon dioxide adsorption performance; at the same time, from Figure 3 Scanning electron micrographs show that the quaternary ammonium-modified polyurethane CO2 adsorbent provided by the present invention retains the high porosity and high specific surface area characteristics of polyurethane, and its adsorption rate is comparable to that of existing CO2 adsorbents. Therefore, the quaternary ammonium-modified polyurethane CO2 adsorbent provided by the present invention improves carbon dioxide adsorption performance without compromising the adsorption rate.

[0056] The present invention also provides a method for direct air capture of carbon dioxide, using the quaternary ammonium-modified polyurethane CO2 adsorbent described in the above technical solution for the adsorption and desorption of carbon dioxide.

[0057] Compared to existing technologies, the preparation method provided by the present invention uses polyurethane as the raw material and, under specific process steps, conditions, and parameters, achieves superior interaction, thereby producing a quaternary ammonium-modified polyurethane CO2 adsorbent. The polyurethane CO2 adsorbent prepared by the present invention is granular, making it more suitable for practical engineering applications compared to existing powdered CO2 adsorbents. Furthermore, the adsorbent exhibits higher CO2 adsorption performance. Experimental results show that the quaternary ammonium-modified polyurethane CO2 adsorbent provided by the present invention has a CO2 adsorption capacity of 1.40 to 1.80 mmol / g.

[0058] At the same time, the raw materials selected and the preparation method provided by the present invention have the advantages of low energy consumption cost, simple process, economy and environmental protection, and therefore have good application prospects in the field of CO2 direct air capture technology.

[0059] In order to further illustrate the present invention, the following examples are provided for detailed description. The raw materials used in the following examples of the present invention are all commercially available.

[0060] Example 1

[0061] (1) Take 0.5 g each of polyurethane black material (isocyanate) and polyurethane white material (combined polyether), mix them at room temperature, and stir rapidly to obtain a first reaction product.

[0062] (2) The first reaction product obtained in step (1) was rinsed with water, dried, and then washed in an ultrasonic cleaner with 6 mL of acetone, anhydrous ethanol, and deionized water for 15 minutes respectively. The product was then immersed in an oxidizing solution (a mixed solution of 0.7% nitric acid and 17% sulfuric acid prepared in a 1:1 (mass ratio)) for 8 hours, filtered, washed with a large amount of water, and dried for later use. The chemically oxidized polyurethane was then immersed in a glutaraldehyde solution for 24 hours, and then immersed in a 3.5 mol / L acrylic acid solution at 40°C for 1.5 hours to carry out a grafting reaction. After completion, the product was washed with ethanol to obtain a second reaction product.

[0063] (3) The second reaction product obtained in step (2) was immersed in a 30% by mass NaOH aqueous solution at room temperature for 4 hours to enhance reactivity, washed with a large amount of water and dried at 60°C to constant weight, then placed in a mixed solution of 30 mL of isopropanol and 5 mL of 3-chloro-2-hydroxypropyltrimethylammonium chloride, and then 4 mL of NaOH aqueous solution was added. The reaction was continued for 4 hours while maintaining the temperature at 40°C. The obtained product was washed with HCl aqueous solution and water in sequence until the pH of the washing solution reached neutrality, thereby obtaining a third reaction product.

[0064] (4) The third reaction product obtained in step (3) was filtered, 50 mL of 0.5 mol / L Na2CO3 solution was added and stirred for 4 h for ion exchange, and then filtered, rinsed with a large amount of deionized water, and filtered again. After repeating the ion exchange process 4 times, the mixture was washed with a large amount of water, filtered, and dried to obtain a quaternary ammonium modified polyurethane CO2 adsorbent.

[0065] The CO2 adsorption detection method is as follows: 0.1g of the material and a carbon dioxide detector are placed in a plexiglass box (the volume of the detection system is 26.5L), and the initial carbon dioxide concentration is recorded as 876ppm. After 120 minutes, the carbon dioxide concentration in the test system no longer changes, and the carbon dioxide concentration at this time is recorded as 716ppm. After conversion, the quaternary ammonium modified polyurethane CO2 adsorbent obtained by the preparation method provided in Example 1 of the present invention has an adsorption capacity of 1.73mmol / g of CO2. The detection methods of other embodiments and comparative examples are the same.

[0066] Example 2

[0067] The preparation method provided in Example 1 was adopted, except that the concentration of acrylic acid in the grafting reaction in step (2) was selected to be 2.5 mol / L, to obtain a quaternary ammonium group-modified polyurethane CO2 adsorbent.

[0068] After testing, the quaternary ammonium modified polyurethane CO2 adsorbent obtained by the preparation method provided in Example 2 of the present invention has an adsorption capacity of 1.53 mmol / g for CO2.

[0069] Example 3

[0070] The preparation method provided in Example 1 was adopted, except that the concentration of acrylic acid in the grafting reaction in step (2) was selected to be 1.0 mol / L, to obtain a quaternary ammonium group-modified polyurethane CO2 adsorbent.

[0071] After testing, the quaternary ammonium modified polyurethane CO2 adsorbent obtained by the preparation method provided in Example 3 of the present invention has an adsorption capacity of 1.41 mmol / g for CO2.

[0072] Comparative Example 1

[0073] The preparation method provided in Example 1 was adopted, except that the temperature of the grafting reaction in step (2) was selected to be 25° C., and step (3) was omitted, and finally a hydroxyl-modified polyurethane CO 2 adsorbent was prepared.

[0074] After testing, it was found that the hydroxyl-modified polyurethane CO2 adsorbent obtained by the preparation method provided in Comparative Example 1 of the present invention had an adsorption capacity of 0 for CO2 and had no adsorption capacity for CO2.

[0075] Comparative Example 2

[0076] The preparation method provided in Example 1 was adopted, except that the temperature of the grafting reaction in step (2) was selected to be 55° C., to obtain a quaternary ammonium group-modified polyurethane CO 2 adsorbent.

[0077] After testing, the quaternary ammonium modified polyurethane CO2 adsorbent obtained by the preparation method provided in Comparative Example 2 of the present invention has an adsorption capacity of 0.87 mmol / g for CO2.

[0078] Comparative Example 3

[0079] The preparation method provided in Example 1 was adopted, except that the grafting reaction time in step (2) was selected to be 0.5 h, to obtain a quaternary ammonium group-modified polyurethane CO2 adsorbent.

[0080] After testing, the quaternary ammonium modified polyurethane CO2 adsorbent obtained by the preparation method provided in Comparative Example 3 of the present invention has an adsorption capacity of 1.07 mmol / g for CO2.

[0081] Comparative Example 4

[0082] The preparation method provided in Example 1 was adopted, except that in step (3), the volume ratio of the NaOH aqueous solution to the 3-chloro-2-hydroxypropyl-trimethylammonium chloride solution was selected to be 2:1, thereby obtaining a quaternary ammonium-modified polyurethane CO2 adsorbent.

[0083] After testing, the quaternary ammonium modified polyurethane CO2 adsorbent obtained by the preparation method provided in Comparative Example 4 of the present invention has an adsorption capacity of 1.12 mmol / g for CO2.

[0084] Comparative Example 5

[0085] The preparation method provided in Example 1 was adopted, except that the volume ratio of the NaOH aqueous solution to the 3-chloro-2-hydroxypropyl-trimethylammonium chloride solution in step (3) was selected to be 1:1, and step (4) was omitted to obtain a quaternary ammonium-modified polyurethane CO2 adsorbent.

[0086] After testing, the quaternary ammonium modified polyurethane CO2 adsorbent obtained by the preparation method provided in Comparative Example 5 of the present invention has an adsorption capacity of 0 for CO2 and has no adsorption capacity for CO2.

[0087] Application Examples

[0088] In actual applications, the material has no special requirements for the adsorption environment. It only needs to be placed in a ventilated and dry environment to dry. During this process, the material will absorb carbon dioxide in the environment by itself. The drier the material, the more carbon dioxide it absorbs.

[0089] For example, place 1g of material on a culture dish and place it in a 40°C oven. Take it out after half an hour. At this time, the material is saturated with adsorption. Then place the material in a plexiglass cavity and atomize and humidify it at room temperature. After humidification, the material will release carbon dioxide by itself. The generated carbon dioxide can be extracted with an air pump for other application scenarios.

[0090] The above-mentioned specific embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to allow people familiar with the technology to implement the technology according to the content of the present invention. It should be pointed out that all embodiments obtained by ordinary technicians in this field without making any creative work, within the principle of the present invention, and only making certain improvements to the present invention, fall within the scope of protection of the present invention.

Claims

1. A method for preparing a quaternary ammonium group-modified polyurethane CO2 adsorbent, characterized in that: The following steps are involved: a) mixing the isocyanate and the composite polyether at room temperature, and rapidly stirring to obtain a first reaction product; b) rinsing the first reaction product obtained in step a) with water, drying it, and then cleaning it in an ultrasonic cleaner with acetone, anhydrous ethanol, and deionized water for 10 to 20 minutes respectively, then soaking it in an oxidizing solution, washing it with water, drying it, and then soaking it in a glutaraldehyde solution for 24 hours. Then, soaking it in an acrylic acid solution at a certain temperature to carry out a grafting reaction, and then washing it with ethanol after completion to obtain a second reaction product; c) soaking the second reaction product obtained in step b) in a NaOH aqueous solution at room temperature for 2 to 6 hours to enhance reactivity, filtering it, washing it with water, and drying it at 60 to 70° C., adding isopropyl alcohol and an aqueous solution of 3-chloro-2-hydroxypropyltrimethylammonium chloride, and then adding an aqueous NaOH solution to carry out a quaternization reaction, and washing the obtained product with an HCl aqueous solution and then water in sequence until the pH of the washing solution reaches neutral, thereby obtaining a third reaction product; d) filtering the third reaction product obtained in step c), adding a Na2CO3 solution to carry out several ion exchange reactions, and finally washing, filtering, and drying to obtain a granular quaternary ammonium modified polyurethane CO2 adsorbent; The chemical reactions of the preparation process are as follows:

2. The preparation method according to claim 1, characterized in that The mass ratio of the isocyanate to the combined polyether in step a) is 1:(1-2).

3. The preparation method according to claim 1, characterized in that The oxidation solution in step b) is a mixed solution of 0.7% nitric acid and 17% sulfuric acid in a mass ratio of 1:1 to 3; the immersion time in the oxidation solution is 6 to 8 hours.

4. The preparation method according to claim 1, characterized in that The molar concentration of acrylic acid in step b) is 1.0 to 3.5 mol / L; the time of the grafting reaction is 1.0 to 2.5 hours; and the temperature of the grafting reaction is 15 to 45°C.

5. The preparation method according to claim 1, characterized in that The mass fraction of the NaOH aqueous solution in step c) is 20-40%.

6. The preparation method according to claim 1, characterized in that In step c), the amount of isopropanol used is 20-40 mL of isopropanol per 1 g of the second reaction product; the mass fraction of the 3-chloro-2-hydroxypropyl-trimethylammonium chloride aqueous solution is 60%, and the amount used is 3-5 mL of the 3-chloro-2-hydroxypropyl-trimethylammonium chloride aqueous solution per 1 g of the second reaction product; the volume ratio of the NaOH aqueous solution to the 3-chloro-2-hydroxypropyl-trimethylammonium chloride aqueous solution is (3-5):

5.

7. The preparation method according to claim 1, characterized in that The quaternization reaction temperature in step c) is 25-40° C., and the reaction time is 3-5 hours.

8. The preparation method according to claim 1, characterized in that The molar concentration of the HCl aqueous solution in step c) is 0.1 mol / L.

9. A quaternary ammonium modified polyurethane CO2 adsorbent, characterized in that: The polyurethane composite material is prepared by the preparation method according to any one of claims 1 to 8 and is in granular form, comprising a polyurethane porous carrier and functional ions loaded therein.

10. The quaternary ammonium group-modified polyurethane CO2 adsorbent according to claim 9 is used for the adsorption and desorption of carbon dioxide, wherein the adsorption capacity of the quaternary ammonium group-modified polyurethane CO2 adsorbent for CO2 is 1.40 to 1.80 mmol / g.

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