Calcium silicate composite adsorbent for DAC (Digital-to-Analog Converter) carbon capture and preparation method of calcium silicate composite adsorbent

Abstract

The invention relates to the technical field of industrial dust removal, in particular to a calcium silicate composite adsorbent for DAC (Digital-to-Analog Converter) carbon capture and a preparation method of the calcium silicate composite adsorbent. The calcium silicate composite adsorbent for DAC carbon capture is prepared from the following raw materials in parts by mass: 5 to 15 parts of sodium silicate, 10 to 20 parts of lauryl sodium sulfate, 1 to 3 parts of amino-terminated polyamidoamine, 1 to 3 parts of graphene oxide, 1 to 2 parts of dopamine, 1 to 2 parts of polyethyleneimine, 0.1 to 0.2 part of glutaraldehyde, 1 to 5 parts of calcium chloride, 1 to 2 parts of sodium lignin sulfonate and 1 to 3 parts of aluminum silicate fiber. And 1-2 parts of silicon dioxide microspheres. According to the present invention, the dust resistance barrier can be provided, the efficient and stable CO2 capture in the industrial dust removal scene is finally achieved, the long-term service ability of the material in the complex industrial environment is ensured, and the preparation method is simple, and is suitable for large-scale promotion and application.

Description

Technical Field

[0001] This invention relates to the field of industrial dust removal technology, and in particular to a calcium silicate composite adsorbent for carbon capture in DAC and its preparation method. Background Technology

[0002] As a non-renewable energy source, the excessive consumption of fossil fuels not only leads to energy depletion, but the large amounts of CO2 emitted during combustion also contribute to the greenhouse effect, posing a serious threat to the global climate. Currently, CO2 capture technology has become a key solution, with Direct Air Capture (DAC) being a hot research topic due to its ability to directly capture carbon dioxide from the atmosphere.

[0003] DAC (Decoupling and Deposition) technology separates CO2 from the air using chemical or physical methods, offering flexible operating conditions and providing a new pathway for carbon capture. Traditional adsorbents are mostly designed for high-concentration CO2 environments; under low-concentration conditions, their adsorption capacity decreases significantly, leading to reduced capture efficiency. Furthermore, in industrial dust removal processes, impurities such as dust and particulate matter can interfere with the adsorbent's performance, further weakening its capture capacity. Existing DAC technology suffers from difficulties in controlling capture conditions during industrial dust removal, resulting in poor absorption performance in low-concentration CO2 environments.

[0004] Existing adsorbents, when used in industrial dust removal environments, suffer from poor absorption and capture performance due to low CO2 concentrations and uncontrollable capture conditions, failing to meet the demands for efficient and low-cost dust collection. Therefore, developing an adsorbent with high adsorption capacity and a broad CO2 concentration absorption range is crucial for advancing DAC (Digital Dioxide Disposal) technology. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a calcium silicate composite adsorbent for carbon capture in DAC and its preparation method.

[0006] A calcium silicate composite adsorbent for carbon capture in DACs comprises the following raw materials by mass: 5-15 parts sodium silicate, 10-20 parts sodium dodecyl sulfate, 1-3 parts amino-terminated polyamide amine, 1-3 parts graphene oxide, 1-2 parts dopamine, 1-2 parts polyethyleneimine, 0.1-0.2 parts glutaraldehyde, 1-5 parts calcium chloride, 1-2 parts sodium lignosulfonate, 1-3 parts aluminum silicate fiber, and 1-2 parts silica microspheres.

[0007] Preferably, the aspect ratio of the aluminum silicate fiber is 100-150:1.

[0008] Preferably, the silica microspheres have a particle size of 10-100 μm.

[0009] Preferably, the generation of the amino-terminated polyamide amine is 2.0-5.0.

[0010] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Add sodium silicate, sodium dodecyl sulfate and amino-terminated polyamide amine to water, and stir at 70-80℃ for 10-30 min under nitrogen protection to obtain pretreated sodium silicate. S2. Add graphene oxide to Tris-HCl buffer and stir until homogeneous. Add dopamine and sonicate for 1-2 hours. Add polyethyleneimine and glutaraldehyde and stir for 5-10 hours. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to water and stir for 10-30 minutes under nitrogen protection. Add it to pretreated sodium silicate and stir at 70-80℃ for 5-10 hours. Add modified graphene and sodium lignosulfonate and continue stirring for 1-2 hours. Cool to room temperature and adjust the pH of the system to 11-12. Add a cold source to the bottom and cool unidirectionally to -20 to -30℃. Keep warm for 10-20 minutes and freeze dry for 10-20 hours. Crush the mixture and add aluminum silicate fiber and silica microspheres and mix evenly.

[0011] Preferably, in S2, the pH value of the Tris-HCl buffer is 8-9.

[0012] Preferably, in S2, the frequency of ultrasonic treatment is 60-80kHz.

[0013] Preferably, in S3, the cooling rate of unidirectional cooling is 1-5℃ / min.

[0014] Preferably, in S3, the freeze-drying temperature is -50 to -60°C.

[0015] A device for capturing carbon in a DAC includes: an absorption device and the aforementioned calcium silicate composite adsorbent for capturing carbon in a DAC fixed on the absorption device.

[0016] Beneficial effects: This invention uses sodium dodecyl sulfate as a template and combines it with dendritic polyamide amine to induce calcium silicate to form a high specific surface area mesoporous structure, which provides abundant active sites and improves the structural stability of the framework. The introduction of modified graphene forms a cross-linked network, which greatly increases the porosity, effectively reduces CO2 diffusion resistance, and achieves rapid mass transfer. The resulting modified graphene is made by cross-linking graphene oxide with dopamine self-polymerization-polyethyleneimine. The abundant amino groups on the surface work synergistically with sodium lignosulfonate to effectively improve the adsorption capacity of the product at low concentrations.

[0017] This invention utilizes silica microspheres to fill the pores of the adsorbent, forming a physical barrier to prevent dust particles from entering, while the high aspect ratio of aluminosilicate fibers enhances mechanical strength, allowing the adsorbent to maintain the integrity of its pore structure in dusty airflow and avoiding performance degradation caused by pore blockage. Furthermore, by adding a unidirectional cold source at the bottom, ice crystals are oriented to grow, and combined with freeze-drying, a regular microporous structure is formed, which significantly reduces CO2 mass transfer resistance and greatly enhances adsorption stability at low concentrations.

[0018] This invention provides a dust barrier, ultimately achieving efficient and stable CO2 capture in industrial dust removal scenarios, ensuring the long-term service capability of the material in complex industrial environments, and the preparation method is simple and suitable for large-scale application. Attached Figure Description

[0019] Figure 1 This is a comparison chart showing the adsorption capacity of the calcium silicate composite adsorbents obtained in Example 5 and Comparative Examples 1-3 for carbon dioxide and nitrogen mixtures.

[0020] Figure 2 This is a comparison chart showing the adsorption capacity and the rate of decrease in carbon dioxide adsorption capacity of the calcium silicate composite adsorbents obtained in Example 5 and Comparative Examples 1-3 for a mixture of carbon dioxide, fly ash, and nitrogen. Detailed Implementation

[0021] The present invention will be further explained below with reference to specific embodiments.

[0022] The aluminosilicate fibers used below were purchased from Lingshou County Mouxin New Material Technology Co., Ltd., with a diameter of 6±2μm and a length of 1±0.1mm. The silica microspheres used below were purchased from Moumu (Ningbo) New Material Co., Ltd., with a particle size of 20μm. The amino-terminated polyamide amine (PAMAM, G4.0) used below was purchased from Hangzhou Mouqiao Biotechnology Co., Ltd. The dopamine used below was purchased from Moupin Chemical Technology (Shanghai) Co., Ltd. The polyethyleneimine used below was purchased from Hubei Mouyuhong Biomedical Technology Co., Ltd.

[0023] Example 1 A calcium silicate composite adsorbent for carbon capture in DACs comprises the following raw materials: 50 mg sodium silicate, 100 mg sodium dodecyl sulfate, 10 mg amino-terminated polyamide amine, 10 mg graphene oxide, 10 mg dopamine, 10 mg polyethyleneimine, 1 mg glutaraldehyde, 10 mg calcium chloride, 10 mg sodium lignosulfonate, 10 mg aluminum silicate fiber, and 10 mg silica microspheres.

[0024] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Add sodium silicate, sodium dodecyl sulfate, and amino-terminated polyamide amine to 1g of deionized water, stir for 10min under nitrogen protection, at a stirring speed of 500r / min and a stirring temperature of 70℃, to obtain pretreated sodium silicate. S2. Add graphene oxide to 400 mg of Tris-HCl buffer solution with pH=9 and stir until homogeneous. Add dopamine and sonicate for 1 h at a frequency of 60 kHz. Add polyethyleneimine and glutaraldehyde and stir for 5 h at a stirring speed of 100 r / min. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to 1g of deionized water and stir for 10min under nitrogen protection at a stirring speed of 500r / min. Add the calcium chloride to the pretreated sodium silicate and stir at 70℃ for 5h at a stirring speed of 1000r / min. Add modified graphene and sodium lignosulfonate and continue stirring for 1h. Cool to room temperature and adjust the pH of the system to 11 using ammonia. Add a cold source to the bottom and unidirectionally cool to -20℃ at a rate of 1℃ / min. Keep warm for 10min and freeze dry at -50℃ for 10h. Grind the mixture through a 60-mesh sieve and add aluminum silicate fiber and silica microspheres and mix evenly.

[0025] Example 2 A calcium silicate composite adsorbent for capturing carbon in DACs comprises the following raw materials: 150 mg sodium silicate, 200 mg sodium dodecyl sulfate, 30 mg amino-terminated polyamide amine, 30 mg graphene oxide, 20 mg dopamine, 20 mg polyethyleneimine, 2 mg glutaraldehyde, 50 mg calcium chloride, 20 mg sodium lignosulfonate, 30 mg aluminum silicate fiber, and 20 mg silica microspheres.

[0026] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Sodium silicate, sodium dodecyl sulfate, and amino-terminated polyamide amine were added to 1.5g of deionized water and stirred for 30min under nitrogen protection at a stirring speed of 1500r / min and a stirring temperature of 80℃ to obtain pretreated sodium silicate. S2. Add graphene oxide to 600 mg of Tris-HCl buffer solution with pH=9 and stir until homogeneous. Add dopamine and sonicate for 2 h at a frequency of 80 kHz. Add polyethyleneimine and glutaraldehyde and stir for 10 h at a stirring speed of 400 r / min. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to 1.5g of deionized water and stir for 30min under nitrogen protection at a stirring speed of 1500r / min. Add the calcium chloride to the pretreated sodium silicate and stir at 80℃ for 10h at a stirring speed of 1500r / min. Add modified graphene and sodium lignosulfonate and continue stirring for 2h. Cool to room temperature and adjust the pH of the system to 12 using ammonia. Add a cold source to the bottom and unidirectionally cool to -30℃ at a rate of 5℃ / min. Keep warm for 20min and freeze dry at -60℃ for 20h. Grind the mixture through a 60-mesh sieve and add aluminum silicate fiber and silica microspheres and mix evenly.

[0027] Example 3 A calcium silicate composite adsorbent for carbon capture in DACs comprises the following raw materials: 80 mg sodium silicate, 180 mg sodium dodecyl sulfate, 15 mg amino-terminated polyamide amine, 25 mg graphene oxide, 12 mg dopamine, 18 mg polyethyleneimine, 1.5 mg glutaraldehyde, 20 mg calcium chloride, 18 mg sodium lignosulfonate, 15 mg aluminum silicate fiber, and 18 mg silica microspheres.

[0028] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Sodium silicate, sodium dodecyl sulfate, and amino-terminated polyamide amine were added to 1.1 g of deionized water and stirred for 25 min under nitrogen protection at a stirring speed of 800 r / min and a stirring temperature of 77 °C to obtain pretreated sodium silicate. S2. Add graphene oxide to 450 mg of Tris-HCl buffer solution with pH=9 and stir until homogeneous. Add dopamine and sonicate for 100 min at a frequency of 65 kHz. Add polyethyleneimine and glutaraldehyde and stir for 9 h at a stirring speed of 200 r / min. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to 1.3g of deionized water and stir for 15min under nitrogen protection at a stirring speed of 1200r / min. Add the calcium chloride to the pretreated sodium silicate and stir at 73℃ for 9h at a stirring speed of 1100r / min. Add modified graphene and sodium lignosulfonate and continue stirring for 100min. Cool to room temperature and adjust the pH of the system to 11.8 using ammonia. Add a cold source to the bottom and unidirectionally cool to -28℃ at a rate of 2℃ / min. Hold at this temperature for 12min and freeze-dry at -58℃ for 12h. Grind the mixture through a 60-mesh sieve and add aluminum silicate fiber and silica microspheres, mixing thoroughly.

[0029] Example 4 A calcium silicate composite adsorbent for carbon capture in DACs comprises the following raw materials: 120 mg sodium silicate, 120 mg sodium dodecyl sulfate, 25 mg amino-terminated polyamide amine, 15 mg graphene oxide, 18 mg dopamine, 12 mg polyethyleneimine, 1.5 mg glutaraldehyde, 40 mg calcium chloride, 12 mg sodium lignosulfonate, 25 mg aluminum silicate fiber, and 12 mg silica microspheres.

[0030] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Sodium silicate, sodium dodecyl sulfate, and amino-terminated polyamide amine were added to 1.3g of deionized water and stirred for 15min under nitrogen protection at a stirring speed of 1200r / min and a stirring temperature of 73℃ to obtain pretreated sodium silicate. S2. Add graphene oxide to 550 mg of Tris-HCl buffer solution with pH=9 and stir until homogeneous. Add dopamine and sonicate for 80 min at a frequency of 75 kHz. Add polyethyleneimine and glutaraldehyde and stir for 7 h at a stirring speed of 300 r / min. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to 1.1g of deionized water and stir for 25min under nitrogen protection at a stirring speed of 800r / min. Add the calcium chloride to the pretreated sodium silicate and stir at 77℃ for 7h at a stirring speed of 1300r / min. Add modified graphene and sodium lignosulfonate and continue stirring for 80min. Cool to room temperature and adjust the pH of the system to 11.3 using ammonia. Add a cold source to the bottom and unidirectionally cool to -22℃ at a rate of 4℃ / min. Hold at this temperature for 18min and freeze-dry at -52℃ for 18h. Grind the mixture through a 60-mesh sieve and add aluminum silicate fiber and silica microspheres, mixing thoroughly.

[0031] Example 5 A calcium silicate composite adsorbent for carbon capture in DACs comprises the following raw materials: 100 mg sodium silicate, 150 mg sodium dodecyl sulfate, 20 mg amino-terminated polyamide amine, 20 mg graphene oxide, 15 mg dopamine, 15 mg polyethyleneimine, 1.5 mg glutaraldehyde, 30 mg calcium chloride, 15 mg sodium lignosulfonate, 20 mg aluminum silicate fiber, and 15 mg silica microspheres.

[0032] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Sodium silicate, sodium dodecyl sulfate, and amino-terminated polyamide amine were added to 1.2g of deionized water and stirred for 20min under nitrogen protection at a stirring speed of 1000r / min and a stirring temperature of 75℃ to obtain pretreated sodium silicate. S2. Add graphene oxide to 500 mg of Tris-HCl buffer solution with pH=9 and stir until homogeneous. Add dopamine and sonicate for 90 min at a frequency of 70 kHz. Add polyethyleneimine and glutaraldehyde and stir for 8 h at a stirring speed of 260 r / min. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to 1.2g of deionized water and stir for 20min under nitrogen protection at a stirring speed of 1000r / min. Add the calcium chloride to the pretreated sodium silicate and stir at 75℃ for 8h at a stirring speed of 1200r / min. Add modified graphene and sodium lignosulfonate and continue stirring for 90min. Cool to room temperature and adjust the pH of the system to 11.5 using ammonia. Add a cold source to the bottom and unidirectionally cool to -25℃ at a rate of 3℃ / min. Hold at this temperature for 15min and freeze-dry at -55℃ for 15h. Grind the mixture through a 60-mesh sieve and add aluminum silicate fiber and silica microspheres and mix evenly.

[0033] Comparative Example 1 A calcium silicate composite adsorbent for carbon capture in DACs comprises the following raw materials: 100 mg sodium silicate, 170 mg sodium dodecyl sulfate, 20 mg graphene oxide, 15 mg dopamine, 15 mg polyethyleneimine, 1.5 mg glutaraldehyde, 30 mg calcium chloride, 15 mg sodium lignosulfonate, 20 mg aluminum silicate fiber, and 15 mg silica microspheres.

[0034] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Add sodium silicate and sodium dodecyl sulfate to 1.2g of deionized water, stir for 20min under nitrogen protection at a stirring speed of 1000r / min and a stirring temperature of 75℃ to obtain pretreated sodium silicate. S2. Add graphene oxide to 500 mg of Tris-HCl buffer solution with pH=9 and stir until homogeneous. Add dopamine and sonicate for 90 min at a frequency of 70 kHz. Add polyethyleneimine and glutaraldehyde and stir for 8 h at a stirring speed of 260 r / min. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to 1.2g of deionized water and stir for 20min under nitrogen protection at a stirring speed of 1000r / min. Add the calcium chloride to the pretreated sodium silicate and stir at 75℃ for 8h at a stirring speed of 1200r / min. Add modified graphene and sodium lignosulfonate and continue stirring for 90min. Cool to room temperature and adjust the pH of the system to 11.5 using ammonia. Add a cold source to the bottom and unidirectionally cool to -25℃ at a rate of 3℃ / min. Hold at this temperature for 15min and freeze-dry at -55℃ for 15h. Grind the mixture through a 60-mesh sieve and add aluminum silicate fiber and silica microspheres and mix evenly.

[0035] Comparative Example 2 A calcium silicate composite adsorbent for carbon capture in DACs comprises the following raw materials: 100 mg sodium silicate, 150 mg sodium dodecyl sulfate, 20 mg amino-terminated polyamide amine, 51.5 mg graphene oxide, 30 mg calcium chloride, 15 mg sodium lignosulfonate, 20 mg aluminum silicate fiber, and 15 mg silica microspheres.

[0036] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Sodium silicate, sodium dodecyl sulfate, and amino-terminated polyamide amine were added to 1.2g of deionized water and stirred for 20min under nitrogen protection at a stirring speed of 1000r / min and a stirring temperature of 75℃ to obtain pretreated sodium silicate. S2. Add calcium chloride to 1.2g of deionized water and stir for 20min under nitrogen protection at a stirring speed of 1000r / min. Add the calcium chloride to the pretreated sodium silicate and stir at 75℃ for 8h at a stirring speed of 1200r / min. Add graphene oxide and sodium lignosulfonate and continue stirring for 90min. Cool to room temperature and adjust the pH of the system to 11.5 using ammonia. Add a cold source to the bottom and unidirectionally cool to -25℃ at a rate of 3℃ / min. Hold at this temperature for 15min and freeze-dry at -55℃ for 15h. Grind the mixture through a 60-mesh sieve and add aluminum silicate fiber and silica microspheres, mixing thoroughly.

[0037] Comparative Example 3 A calcium silicate composite adsorbent for carbon capture in DACs comprises the following raw materials: 100 mg sodium silicate, 150 mg sodium dodecyl sulfate, 20 mg amino-terminated polyamide amine, 20 mg graphene oxide, 15 mg dopamine, 15 mg polyethyleneimine, 1.5 mg glutaraldehyde, 30 mg calcium chloride, 15 mg sodium lignosulfonate, 20 mg aluminum silicate fiber, and 15 mg silica microspheres.

[0038] The above-mentioned method for preparing calcium silicate composite adsorbent for carbon capture in DAC includes the following steps: S1. Sodium silicate, sodium dodecyl sulfate, and amino-terminated polyamide amine were added to 1.2g of deionized water and stirred for 20min under nitrogen protection at a stirring speed of 1000r / min and a stirring temperature of 75℃ to obtain pretreated sodium silicate. S2. Add graphene oxide to 500 mg of Tris-HCl buffer solution with pH=9 and stir until homogeneous. Add dopamine and sonicate for 90 min at a frequency of 70 kHz. Add polyethyleneimine and glutaraldehyde and stir for 8 h at a stirring speed of 260 r / min. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to 1.2g of deionized water and stir for 20min under nitrogen protection at a stirring speed of 1000r / min. Add the calcium chloride to the pretreated sodium silicate and stir at 75℃ for 8h at a stirring speed of 1200r / min. Add modified graphene and sodium lignosulfonate and continue stirring for 90min. Cool to room temperature and adjust the pH of the system to 11.5 using ammonia. Add a cold source around the system and cool to -25℃ at a rate of 3℃ / min. Keep warm for 15min and freeze dry at -55℃ for 15h. Grind the mixture through a 60-mesh sieve and add aluminum silicate fiber and silica microspheres and mix evenly.

[0039] Take 1.5g of the calcium silicate composite adsorbent obtained in Example 5 and Comparative Examples 1-3, and load them into fixed beds to form adsorption columns. Then, purge with nitrogen gas at a flow rate of 150mL / min for 5min. Next, switch the nitrogen gas to a mixture of carbon dioxide and nitrogen with a carbon dioxide content of 200ppm. Keep the gas flow rate constant. At the same time, use a flue gas analyzer to analyze the concentration of the gas after passing through the adsorption column. Continue for 48h and calculate the amount of carbon dioxide adsorbed.

[0040]

[0041] Where q is the amount of carbon dioxide adsorbed, mmol / g; Q is the flow rate of the mixed gas, mL / min; t is the adsorption reaction time, s; C0 is the volume fraction of carbon dioxide in the mixed gas, %; C is the volume fraction of carbon dioxide in the adsorbed tail gas at time t, %; and W is the mass of the adsorbent, g.

[0042] like Figure 1 As shown, the calcium silicate composite adsorbent obtained in Example 5 has the highest carbon dioxide adsorption capacity, which is significantly better than that of the comparative example.

[0043] Subsequently, the test was repeated following the same steps, except the carbon dioxide and nitrogen mixture was replaced with a mixture of carbon dioxide, fly ash, and nitrogen. A rotary aerosol generator was used to disperse the fly ash particles and stably feed them into the mixed gas stream. The carbon dioxide content remained at 200 ppm, while the fly ash flow rate was 1.5 μg / min (equivalent to 10 mg / m³). 3 To simulate factory exhaust gas.

[0044] Calculate the amount of carbon dioxide adsorbed and compare it with the previous experiment to calculate the rate of decrease in the amount of carbon dioxide adsorbed.

[0045] like Figure 2 As shown, the calcium silicate composite adsorbent obtained in Example 5 still has the highest carbon dioxide adsorption capacity, exceeding 2 mmol / g, and the lowest rate of decrease in carbon dioxide adsorption capacity, which is significantly better than the comparative example.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A calcium silicate composite adsorbent for carbon capture in DACs, characterized in that, The raw materials, by weight, include: 5-15 parts sodium silicate, 10-20 parts sodium dodecyl sulfate, 1-3 parts amino-terminated polyamide amine, 1-3 parts graphene oxide, 1-2 parts dopamine, 1-2 parts polyethyleneimine, 0.1-0.2 parts glutaraldehyde, 1-5 parts calcium chloride, 1-2 parts sodium lignosulfonate, 1-3 parts aluminum silicate fiber, and 1-2 parts silica microspheres.

2. The calcium silicate composite adsorbent for carbon capture in DAC according to claim 1, characterized in that, The aspect ratio of aluminum silicate fiber is 100-150:

1.

3. The calcium silicate composite adsorbent for carbon capture in DAC according to claim 1, characterized in that, The silica microspheres have a particle size of 10-100 μm.

4. The calcium silicate composite adsorbent for carbon capture in DAC according to claim 1, characterized in that, The generation of terminal amino-terminated polyamide amines is 2.0-5.

0.

5. A method for preparing a calcium silicate composite adsorbent for carbon capture in DACs as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Add sodium silicate, sodium dodecyl sulfate and amino-terminated polyamide amine to water, and stir at 70-80℃ for 10-30 min under nitrogen protection to obtain pretreated sodium silicate. S2. Add graphene oxide to Tris-HCl buffer and stir until homogeneous. Add dopamine and sonicate for 1-2 hours. Add polyethyleneimine and glutaraldehyde and stir for 5-10 hours. Filter, wash, and vacuum dry to obtain modified graphene. S3. Add calcium chloride to water and stir for 10-30 minutes under nitrogen protection. Add it to pretreated sodium silicate and stir at 70-80℃ for 5-10 hours. Add modified graphene and sodium lignosulfonate and continue stirring for 1-2 hours. Cool to room temperature and adjust the pH of the system to 11-12. Add a cold source to the bottom and cool unidirectionally to -20 to -30℃. Keep warm for 10-20 minutes and freeze dry for 10-20 hours. Crush the mixture and add aluminum silicate fiber and silica microspheres and mix evenly.

6. The method for preparing the calcium silicate composite adsorbent for carbon capture in DAC according to claim 5, characterized in that, In S2, the pH of the Tris-HCl buffer solution is 8-9.

7. The method for preparing the calcium silicate composite adsorbent for carbon capture in DAC according to claim 5, characterized in that, In S2, the frequency of ultrasonic treatment is 60-80kHz.

8. The method for preparing the calcium silicate composite adsorbent for carbon capture in DAC according to claim 5, characterized in that, In S3, the cooling rate of unidirectional cooling is 1-5℃ / min.

9. The method for preparing the calcium silicate composite adsorbent for carbon capture in DAC according to claim 5, characterized in that, In S3, the freeze-drying temperature is -50 to -60℃.

10. A device for capturing carbon using a DAC, characterized in that, include: The absorption device and the calcium silicate composite adsorbent for carbon capture in DAC as described in any one of claims 1-4, fixed on the absorption device.

Images