Preparation Method and Application of a Carbon Capture Material for Capturing Water from Low-Humidity Air

Abstract

The present application provides a preparation method and application of a carbon capture material for low-humidity air water capture, comprising the following steps: S1. Mix a porous carrier suspension with an organic amine solution, filter and vacuum dry to obtain a composite; S2. React with a halogenated alkane and the composite as raw materials to obtain a modified organic amine porous material; S3. React with an inorganic salt and the modified organic amine porous material as raw materials to obtain a precursor of a water capture type adsorption material; S4. Perform solvent exchange and freeze drying on the precursor of the water capture type adsorption material to obtain a carbon capture material for low-humidity air water capture; Through the combination of material selection and various modification means, the present application simultaneously separates and captures CO2 and water molecules from the air, and also ensures the cyclic stability of the carbon separation and capture material.

Description

Technical Field

[0001] The present invention relates to the technical field of separating CO2 and moisture from air, and particularly relates to a preparation method and application of a water-harvesting carbon capture material for low-humidity air. Background Art

[0002] Direct air carbon capture technology (DAC) captures excessive CO2 emissions from the atmosphere and separates CO2 from the air, which can solve the problem of distributed CO2 emissions. After separating CO2 from the air through DAC technology and then using the captured CO2 to form a carbon cycle closed loop, net-zero CO2 emissions can be achieved. In addition, DAC materials can also separate and absorb some moisture from the air, synchronously achieving the effect of separating water and CO2 from the air, which helps to reduce the content of greenhouse gases and solve problems such as water resource shortage.

[0003] Solid amines have good separation and adsorption effects on high-concentration CO2. In related technologies, solid amine adsorbents are also applied to the DAC process. However, solid amine adsorbents also have some disadvantages under low-humidity conditions, such as slow CO2 separation rate, low CO2 separation and capture amount, low separation and water capture amount, etc. On the other hand, moisture in the air is separated and adsorbed by solid amines. The solid amines adsorbed with water molecules require high energy consumption when desorbing water molecules, and organic amines will be lost during the process of desorbing water molecules, resulting in poor cyclic stability of the solid amine adsorbent in separating water and CO2 from the air again, thereby affecting the separation and capture effects of CO2 and water molecules.

[0004] Therefore, it is necessary to provide a DAC material to improve the effects of separating CO2 and water molecules from the air under low humidity. Summary of the Invention

[0005] Aiming at the defects in the prior art, the present invention proposes a preparation method and application of a water-harvesting carbon capture material for low-humidity air to solve the technical problem of how to improve the effects of separating CO2 and water molecules from the air by solid amine adsorption materials under low humidity.

[0006] To solve the above technical problems, the present application provides the following technical solutions:

[0007] In a first aspect, the present application provides a preparation method of a water-harvesting carbon capture material for low-humidity air, including the following steps:

[0008] S1. Mix a porous carrier suspension with an organic amine solution, filter and vacuum dry to obtain a composite;

[0009] S2. Use a halogenated alkane and the composite as raw materials to carry out a reaction to obtain a modified organic amine porous material;

[0010] S3. React the inorganic salt and the modified organic amine porous material as raw materials to obtain a precursor of the water-capturing adsorption material;

[0011] S4. Perform solvent exchange and freeze-drying on the precursor of the water-capturing adsorption material to obtain the low-humidity air water-capturing carbon capture material.

[0012] Preferably, in step S1, the porous carrier includes one or more of silica, alumina, molecular sieve, and resin.

[0013] Preferably, in step S1, the mass ratio of the porous carrier to the organic amine is 1: (0.4 - 1.2).

[0014] Preferably, in step S2, the haloalkane includes one or more of dichloroethane, dibromoethane, and epichlorohydrin.

[0015] Preferably, in step S2, the molar ratio of the haloalkane to the organic amine in step S1 is (0.1 - 0.5): 1.

[0016] Preferably, in step S3, the inorganic salt includes one or more of calcium chloride, magnesium chloride, and lithium chloride.

[0017] Preferably, in step S3, the molar ratio of the inorganic salt to the organic amine is (0.05 - 0.15): 1.

[0018] Preferably, in step S4, the solvent used for solvent exchange is a mixed solution of 2-methyl-2-propanol and water with a volume ratio of (1 - 5): 1.

[0019] In a second aspect, the present application provides a low-humidity air water-capturing carbon capture material.

[0020] In a third aspect, the present application provides an application of the low-humidity air water-capturing carbon capture material in simultaneously separating CO2 and H2O from air under the condition of RH ≤ 50%.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] The present application uses metal salt modification to increase the water adsorption amount of the organic amine in low-humidity air, and at the same time drives the increase of the CO2 adsorption amount to improve the separation amount of CO2 and water in low-humidity air; at the same time, the combination of the metal salt and the organic amine overcomes the defect that the organic amine is lost due to the high dehydration temperature of the metal salt, and improves the cycle stability of the low-humidity air water-capturing carbon capture material in separating CO2 and water from air;

[0023] In this application, the organic amine is modified with halogenated alkane to improve the stability of the organic amine, further ensuring the cyclic stability of the low-humidity air water-harvesting carbon capture material when desorbing water molecules after completing the process of separating CO2 and water molecules from the air, thereby improving the adsorption effect of the low-humidity air water-harvesting carbon capture material on CO2 and water molecules in a low-humidity environment, and the separation effect is stable;

[0024] In this application, the formation of ice crystals in the pores is controlled by selecting porous materials and through solvent exchange and freeze-drying steps, the pore structure of the porous material is regulated, and the adsorption rate of the low-humidity air water-harvesting carbon capture material for separating CO2 and water molecules from the air is increased. Detailed implementation manners

[0025] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] In the related art, materials such as MOFs, COFs, and hygroscopic salts all have unstable problems. The structures of MOFs and COFs are easily damaged during the adsorption and desorption of water, and the salts are prone to leakage during the water absorption process of hygroscopic salts, all of which will lead to a decrease in the recycling performance of the materials.

[0027] The inventor found that due to the low water content in a low-humidity environment, the separation and capture effects of CO2 and water molecules from the air by DAC materials are not good, which are reflected in the following aspects: 1. The adsorption amount and adsorption rate of water are low; 2. The adsorption amount and adsorption rate of CO2 are low; 3. The cyclic stability of DAC materials is poor, resulting in a vicious cycle in the capture and separation of water and CO2. At the same time, there is also a correlation between the separation and capture of water and the separation and capture of CO2: too little water adsorption is not conducive to improving the CO2 adsorption amount and also fails to achieve the effect of water resource reuse, but too much water adsorption will reduce the CO2 adsorption rate. At the same time, the desorption process after adsorbing water will reduce the stability of DAC materials, but if the adsorbed water is not desorbed, the recycling cannot be achieved. Therefore, how to balance the efficient and synchronous separation and capture of CO2 and water molecules while ensuring the cyclic stability of the adsorption material is the key to improving the separation and capture performance of DAC materials in a low-humidity environment.

[0028] Based on this, the present invention was created.

[0029] This application provides a preparation method for a low-humidity air water-harvesting carbon capture material, including the following steps:

[0030] S1. Mix the porous carrier suspension with the organic amine solution, filter and dry under vacuum to obtain a composite;

[0031] S2. Use the haloalkane and the composite as raw materials to carry out a reaction to obtain a modified organic amine porous material;

[0032] S3. Use the inorganic salt and the modified organic amine porous material as raw materials to carry out a reaction to obtain a precursor of the water-capturing adsorption material;

[0033] S4. Carry out solvent exchange and freeze-drying on the precursor of the water-capturing adsorption material to obtain the water-capturing carbon capture material for low-humidity air.

[0034] The preparation process of the water-capturing carbon capture material for low-humidity air in this application is as follows: First, through step S1, organic amine molecules with adsorption characteristics for CO2 are loaded into the pores of the porous carrier to obtain a composite (i.e., a solid amine adsorption material); through step S2, the composite is confined and modified by the haloalkane to improve the stability of the organic amine in the porous carrier; through step S3, an inorganic salt with a water-absorbing function is introduced into the material pores to improve the capture effect and cycle stability for water and CO2; through step S4, solvent exchange and freeze-drying can control the formation of ice crystals in the pores, regulate the pore structure of the material, increase the pore volume, and enhance the capture rate of water and CO2.

[0035] After obtaining the highly stable modified organic amine porous material in this application, metal inorganic salts are introduced, which not only utilize the advantages of the metal inorganic salts themselves but also overcome their own disadvantages. The mechanism is as follows: Since the metal inorganic salt is weakly acidic, it can combine with organic amine molecules through acid-base interaction. Therefore, the water-absorbing property (hydrophilicity) of the metal inorganic salt can be used to increase the water capture amount of the material, and at the same time, the increase in the water capture amount is conducive to promoting the increase in the CO2 adsorption amount; however, the metal inorganic salt itself has a strong binding ability with water molecules, and the energy consumption required for desorbing water molecules is too high, and the thermal stability of the organic amine is also limited. After the metal inorganic salt in this application combines with the organic amine molecules, the binding ability of the metal inorganic salt to water molecules is weakened, the energy consumption for water molecule desorption is reduced, and the water molecules can be desorbed at a low temperature (60 - 95 °C). At the same time, after the metal inorganic salt combines with the organic amine molecules, the stability of the organic amine can be improved, jointly avoiding the loss of the organic amine caused by too high desorption temperature from two aspects, and thus improving the cycle stability of the carbon capture material.

[0036] It should be noted that, on the basis of the above effects, this application also has the effect of balancing high water absorption rate and CO2 capture. The mechanism is that although water molecules can promote CO2 adsorption, too high a water absorption rate will cause the adsorption penetration rate of the adsorbent for CO2 to slow down and the adsorption penetration time to be longer, which is not conducive to industrial application. It will also cause the adsorbent material to agglomerate, affecting the mass transfer and heat transfer of the material. The reason is that the enhanced effect of chemical water capture in the material will cause the weakening of the physical water capture effect, thereby reducing the adsorption of CO2. To address the above problems, this application uses the selection of porous materials and the ice crystal template method (which means that after the solvent-exchanged material is placed in a low-temperature (-20°C or below) condition for freeze-drying for more than 8 hours, the solvent in the pores forms ice crystals, and the ice crystals form large ice crystal particles through the processes of nucleation and nuclear growth. When freeze-drying, the ice crystal template volatilizes to form pores, retaining the void structure of the material) to retain as much of the void structure of the carrier as possible, avoiding the slow diffusion rate and the decrease in adsorption capacity caused by pore blockage after organic amine loading, improving the problem of the too slow CO2 penetration rate caused by too high a water absorption rate, and also using the water absorption effect of metal salts to weaken the decrease in the contact probability between CO2 and amine groups caused by the combination of excessive water molecules and organic amines, thereby increasing the CO2 adsorption capacity.

[0037] In summary, under an air atmosphere, this application can efficiently and synchronously separate and capture CO2 and water molecules while ensuring the cyclic stability of the carbon capture material.

[0038] In some embodiments, in step S1, the porous carrier includes one or more of silica, alumina, molecular sieve, and resin.

[0039] Preferably, the pore volume of the porous carrier is 0.8 - 2.0 cm 3 / g.

[0040] In this embodiment, selecting a porous carrier with a large pore volume is beneficial to improving the adsorption rates of water and CO2. At the same time, the porous carrier with a large pore volume is the basis for maintaining a large pore volume using the ice crystal template method. It should be noted that the pore volume of the porous carrier in this application is preferably 0.8 - 2.0 cm 3 / g. The reason is that a carrier with too small a pore volume is not conducive to the loading of organic amines, while too large a pore volume requires higher requirements for the material preparation process and cost. After the carrier with a large pore volume is loaded with organic amines, the specific surface area and pore volume decrease significantly, and the disordered accumulation of organic amines in the pores is also not conducive to the diffusion of CO2 in the pores. The ice crystal template method forms ice crystals from the water molecules in the pores, nucleates and grows, and finally removes the ice crystal template through freeze-drying, opening some of the originally blocked pores in the pores, providing channels for the diffusion of water molecules and CO2.

[0041] In some embodiments, in step S1, the mass ratio of the porous carrier to the organic amine is 1: (0.4 - 1.2).

[0042] In this embodiment, excessive loading of organic amine will cause accumulation of organic amine, insufficient exposure of active sites, low utilization rate of amino groups, and increased raw material cost; while insufficient loading of organic amine results in low adsorption capacity of the material.

[0043] In some embodiments, in step S2, the haloalkane includes one or more of dichloroethane, dibromoethane, and epichlorohydrin; and the organic amine includes one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0044] In this embodiment, the haloalkane has characteristics such as a highly reactive carbon-halogen bond, moderate boiling point and polarity. The haloalkane exhibits excellent reactivity during the reaction with the organic amine. As a leaving group, the halogen is easily removed, and it has advantages such as fast reaction rate and few by-products.

[0045] In some embodiments, in step S2, the molar ratio of the haloalkane to the organic amine is (0.1 - 0.5):1. The reaction process of the haloalkane and the organic amine is as follows: The haloalkane and the organic amine are dispersed in an alcohol solution, and the reaction is carried out at 50 - 60 °C for 2 - 3 h under anaerobic conditions, followed by vacuum drying.

[0046] In this embodiment, an excess of haloalkane will cause the amino groups in the organic amine to be consumed (primary amine becomes secondary amine, and secondary amine transforms into tertiary amine which has no adsorption ability under dry conditions), reducing the adsorption capacity.

[0047] In some embodiments, in step S3, the inorganic salt is a metal inorganic salt, and the inorganic salt includes one or more of calcium chloride, lithium chloride, and magnesium chloride.

[0048] In this embodiment, the inorganic metal salt is a chloride salt of an alkali / alkaline earth metal, which has strong hygroscopicity and can form a hexahydrate; if other metal salts are selected, on the one hand, they do not have strong hygroscopicity, and on the other hand, they may catalyze the oxidative degradation of the organic amine under high-temperature and oxygen-containing conditions, resulting in a decrease in the stability of the material.

[0049] In some embodiments, in step S3, the molar ratio of the inorganic salt to the organic amine is (0.05 - 0.15):1. The reaction conditions for the inorganic salt and the modified organic amine porous material are as follows: The inorganic salt and the modified organic amine are dispersed in an alcohol solution, and the reaction is carried out at room temperature (20 - 30 °C) for 12 - 18 h.

[0050] In this embodiment, if the amount of the inorganic salt used is excessive, the water absorption will increase, the CO2 adsorption rate will decrease, and the adsorption capacity will also become smaller; however, the inorganic salt is acidic and will combine with the basic organic amine, increasing the stability of the organic amine in the pores.

[0051] In some embodiments, in step S4, the solvent is a mixed solution of 2-methyl-2-propanol and water with a volume ratio of (1-5):1. The process of step S4 is as follows: After mixing the alcohol solution of the water-capturing adsorbent material precursor with the solvent, a solvent exchange reaction is carried out at room temperature (20-30 °C) for 12-18 h, then the solid sample is frozen into ice crystals, and then freeze-dried.

[0052] In this embodiment, the pores of the porous material are regulated based on nanopore confinement modification and ice crystal templating method; the solvent in this embodiment can be freeze-dried, has a small surface tension, and will not cause the pore structure to collapse during the thermal drying process.

[0053] It should be noted that the material preparation of this application has strict requirements on the order of steps: first load the organic amine, and then carry out the nano-confinement modification, which can improve the stability of the material. If the organic amine is modified first and then the modified organic amine is loaded, the effective loading amount of the carrier for the organic amine may decrease; similarly, after the organic amine is loaded and confined and then the metal salt is loaded, it has a promoting effect on the overall adsorption performance and stability of the material. If the order of steps S2 and S3 is changed, that is, the metal salt is loaded first and then the haloalkane modification is carried out, the adsorption performance will decrease. The reason is that, on the one hand, the binding between the metal salt and the organic amine is strong, resulting in a strong weakening effect on the alkalinity of the organic amine and a decrease in the water adsorption rate of the material. On the other hand, the binding between the metal salt and the organic amine will inhibit the modification of the organic amine by the haloalkane; the ice crystal templating method is used in the last step of this application to dredge some pores that may be blocked during the loading of the organic amine. If this step is used in advance or changed, it may cause defects in the pores being blocked during the loading and modification process.

[0054] This application provides a low-humidity air water-capturing carbon capture material.

[0055] This application provides an application of a low-humidity air water-capturing carbon capture material under the condition of RH≤50%.

[0056] The following further illustrates this solution through specific embodiments.

[0057] Example 1

[0058] A preparation method of a low-humidity air water-capturing carbon capture material includes the following steps:

[0059] S1. After degassing 1 part by mass of porous silica (CAS: 7631-86-9), it is dispersed in 50 parts by volume of methanol solution to obtain a porous carrier suspension; 0.66 part by mass of diethylenetriamine is dissolved in 30 parts by volume of methanol to obtain an organic amine solution; the organic amine solution is added dropwise to the porous carrier suspension, ultrasonic treatment is carried out for 0.5 h, and then stirred at room temperature for 24 h. After filtration and drying, a composite is obtained;

[0060] S2. Redisperse the complex in 50 parts by volume of methanol solution, then add 0.13 part by mass of dichloroethane (molar ratio to diethylenetriamine is 0.2:1), react at 50 °C for 24 h under anaerobic conditions, filter and then dry in vacuum to obtain the modified organic amine porous material;

[0061] S3. Disperse the modified organic amine porous material in methanol solution, then add 0.07 part by mass of calcium chloride (molar ratio to diethylenetriamine is 0.1:1), react at 25 °C for 12 h to obtain the precursor of the water-capturing adsorbent material (liquid containing methanol);

[0062] S4. Mix the precursor of the water-capturing adsorbent material with a mixed solution of 2-methyl-2-propanol and water with a volume ratio of 3:1, conduct solvent exchange at 25 °C for 24 h, then freeze the solid sample to form ice crystals, and freeze-dry at -20 °C for 10 h to obtain the low-humidity air water-capturing carbon capture material.

[0063] Example 2

[0064] A preparation method of a low-humidity air water-capturing carbon capture material, comprising the following steps:

[0065] S1. After degassing treatment, disperse 1 part by mass of molecular sieve (CAS: 12173-28-3) in 50 parts by volume of methanol solution to obtain a porous carrier suspension; dissolve 0.66 part by mass of ethylenediamine in 30 parts by volume of methanol to obtain an organic amine solution; dropwise add the organic amine solution into the porous carrier suspension, ultrasonically treat for 0.5 h, then stir at room temperature for 24 h, filter and dry to obtain the complex;

[0066] S2. Redisperse the complex in 50 parts by volume of methanol solution, then add 0.2 part by mass of epichlorohydrin (molar ratio to ethylenediamine is 0.2), react at 60 °C for 24 h under anaerobic conditions, filter and then dry in vacuum to obtain the modified organic amine porous material;

[0067] S3. Disperse the modified organic amine porous material in methanol solution, then add 0.05 part by mass of lithium chloride (molar ratio to ethylenediamine is 0.1), react at 25 °C for 12 h to obtain the precursor of the water-capturing adsorbent material (liquid containing methanol);

[0068] S4. Mix the precursor of the water-capturing adsorbent material with a mixed solution of 2-methyl-2-propanol and water with a volume ratio of 4:1, conduct solvent exchange at 25 °C for 24 h, then freeze the solid sample to form ice crystals, and freeze-dry at -20 °C for 10 h to obtain the low-humidity air water-capturing carbon capture material.

[0069] Example 3

[0070] A preparation method of a carbon capture material for water harvesting from low-humidity air, the other contents are the same as those in Example 1, the difference is that the amount of the porous carrier remains unchanged, but the mass ratio of the porous carrier to the organic amine is 1:2.

[0071] Example 4

[0072] A preparation method of a carbon capture material for water harvesting from low-humidity air, the other contents are the same as those in Example 1, the difference is that the amount of the organic amine remains unchanged, but the molar ratio of the haloalkane to the organic amine is 1:1.

[0073] Example 5

[0074] A preparation method of a carbon capture material for water harvesting from low-humidity air, the other contents are the same as those in Example 1, the difference is that the amount of the organic amine remains unchanged, but the molar ratio of the inorganic salt to the organic amine is 0.3:1.

[0075] Comparative Example 1

[0076] A preparation method of a carbon capture material, the other contents are the same as those in Example 1, the difference is that the composite obtained in step S1 is not modified with a haloalkane, that is, step S2 is not included.

[0077] Comparative Example 2

[0078] A preparation method of a carbon capture material, the other contents are the same as those in Example 1, the difference is that the obtained modified organic amine porous material is not modified with a metal inorganic salt, that is, step S3 is not included.

[0079] Comparative Example 3

[0080] A preparation method of a carbon capture material, the other contents are the same as those in Example 1, the difference is that steps S2 and S3 are not included.

[0081] Comparative Example 4

[0082] A preparation method of a carbon capture material, the other contents are the same as those in Example 1, the difference is that the order of the haloalkane modification and the metal inorganic salt modification is reversed, that is, the process orders of steps S2 and S3 are exchanged.

[0083] Comparative Example 5

[0084] A preparation method of a carbon capture material, the other contents are the same as those in Example 1, the difference is that the water-harvesting adsorbent precursor obtained in step S3 is vacuum dried, that is, the freeze drying in step S4 is replaced by vacuum drying.

[0085] Testing and Evaluation

[0086] The carbon capture materials obtained from each example and comparative example were placed in a quartz tube and separated and adsorbed CO2 and moisture in an air stream at a temperature of 25 °C and a humidity of 30%. After adsorption saturation (about 12 h), the water absorption rate, CO2 adsorption capacity, water adsorption rate per unit adsorbent, and CO2 adsorption rate of the carbon capture materials were measured. The steps were as follows: At the outlet of the quartz tube, a gas chromatograph and a humidity analyzer were used to measure the CO2 concentration and moisture content in the outlet gas, respectively, and the CO2 and moisture adsorption amounts were obtained by integral calculation; the adsorption rate was relatively fast in the first few hours during the adsorption process. To better evaluate the adsorption performance, the CO2 adsorption rate was the average adsorption rate in the first 3 h, and the water adsorption rate was the average adsorption rate in the first 5 h. The results are shown in Table 1.

[0087] Table 1 Test results of adsorption performance

[0088]

[0089] The carbon capture materials after adsorption saturation (12 h) were passed through a hot inert gas for desorption experiments at 90 °C, and the desorbed materials were used for cyclic tests of adsorption capacity in an air stream. The results are shown in Table 2.

[0090] Table 2 Test results of desorption performance

[0091]

[0092] As can be seen from Table 1 and Table 2, Examples 1 and 2 had higher CO2 and moisture adsorption capacities, faster adsorption rates, and good cyclic stability. In Example 3, the excessive loading of organic amine led to pore blockage, and the active sites could not be fully exposed, resulting in a decrease in CO2 adsorption capacity and a slower adsorption rate. In Example 4, the increase in the ratio of halogenated alkane to organic amine consumed the active sites in the organic amine, resulting in a decrease in both CO2 adsorption capacity and adsorption rate. In Example 5, the increase in the amount of metal salt used increased the binding ratio of metal salt to organic amine, resulting in a decrease in CO2 adsorption capacity, but a slight increase in water absorption amount and water absorption rate.

[0093] Halogenated alkanes modified organic amines can improve the stability of materials, and the introduction of metal salts can simultaneously improve the stability and water absorption rate of materials. In Comparative Example 1, the organic amine was not modified, and the CO2 adsorption capacity and adsorption rate of the adsorbent were improved, but the cyclic stability was poor. In Comparative Example 2, the adsorbent without inorganic salt modification had a low water capture amount from the air. Due to the absence of the interaction between the inorganic salt and the organic amine, the active sites of the organic amine were not consumed, and the CO2 adsorption capacity was improved, but the overall cyclic stability also decreased. Similarly, in Comparative Example 3, without modification by halogenated alkanes and metal salts, the CO2 adsorption capacity and adsorption rate were improved, but the water adsorption rate decreased and the cyclic stability was poor. In Comparative Example 4, the order of steps S2 and S3 was changed, and the metal salt first combined with the organic amine, resulting in a strong weakening effect on the alkalinity of the organic amine and a decrease in the water adsorption rate of the material. In Comparative Example 5, vacuum drying was used instead of freeze drying. Due to the large surface tension of water, the volatilization of water easily caused the collapse of the pore structure, resulting in a decrease in the adsorption rate and adsorption capacity of the material.

[0094] The above results show that the low-humidity air water capture type carbon capture material prepared in this application has good effects of simultaneously separating CO2 and H2O from the air under the condition of RH ≤ 50%.

[0095] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a carbon capture material for low-humidity air water capture, characterized in that, It includes the following steps: S1. Mix the porous carrier suspension with the organic amine solution, filter, and then conduct vacuum drying to obtain a composite; S2. Use the haloalkane and the said composite as raw materials to conduct a reaction to obtain a modified organic amine porous material; S3. Use the inorganic salt and the said modified organic amine porous material as raw materials to conduct a reaction to obtain a precursor of the water-trapping adsorption material; S4. Conduct solvent exchange and freeze drying on the said precursor of the water-trapping adsorption material to obtain the low-humidity air water-trapping carbon capture material; in step S2, the haloalkane includes one or more of dichloroethane, dibromoethane, and epichlorohydrin; in step S3, the inorganic salt includes one or more of calcium chloride, magnesium chloride, and lithium chloride; in step S1, the mass ratio of the porous carrier to the organic amine is 1: (0.4 - 1.2); in step S2, the molar ratio of the haloalkane to the organic amine in step S1 is (0.1 - 0.5): 1; in step S3, the molar ratio of the inorganic salt to the organic amine is (0.05 - 0.15): 1; in step S4, the solvent used for solvent exchange is a mixed solution of 2-methyl-2-propanol and water with a volume ratio of (1 - 5):

1.

2. The preparation method of the low-humidity air water capture type carbon capture material according to claim 1, wherein, In step S1, the porous carrier includes one or more of silica, alumina, molecular sieve, and resin.

3. A low-humidity air water-trapping carbon capture material obtained by the preparation method according to any one of claims 1 - 2.

4. Application of the low-humidity air water-trapping carbon capture material according to claim 3 in simultaneously separating CO2 and H2O from air under the condition of RH ≤ 50%.

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