Preparation method of biomass carbon aerogel material and application thereof

Abstract

The present application belongs to the technical field of biomass materials, and particularly relates to a biomass carbon aerogel and a preparation method and application thereof. The present application provides a preparation method of a biomass carbon aerogel, comprising the following steps: mixing corrugated paper and water to obtain a suspension; filtering the suspension in a mold, performing solvent replacement with anhydrous ethanol, and drying after static forming to obtain a blank; after oscillation activation of the blank in a phosphoric acid ethanol solution, the biomass carbon aerogel is obtained through carbonization. The present application takes household waste corrugated paper as a precursor, takes phosphoric acid as an activator, and obtains the carbon aerogel material through the methods of sol-gel, chemical activation and high-temperature carbonization. The preparation method is simple in process, low in cost of raw materials, small in environmental footprint, suitable for large-scale production, and the prepared carbon aerogel material has low density, high specific surface area, high micropore ratio and good carbon dioxide adsorption performance.

Description

Technical Field

[0001] This invention belongs to the field of biomass materials technology, specifically relating to a biomass carbon aerogel, its preparation method, and its application. Background Technology

[0002] To address global warming, various sustainable carbon dioxide capture strategies have been developed. Carbon capture and storage (CCS) technology is crucial for reducing carbon dioxide emissions and can benefit various industries. Adsorption separation technology is a major CCS technology, using materials including zeolites, activated carbon, metal-organic frameworks, and carbon molecular sieves. Although many such adsorbents have been reported to have extremely high adsorption capacity and carbon dioxide selectivity, the use of non-renewable resources and complex manufacturing processes remain major obstacles to widespread application. Broadly speaking, an ideal carbon dioxide adsorbent should possess certain specific properties, including high specific surface area, rapid adsorption and desorption kinetics, a mild adsorption and desorption temperature range, and excellent regeneration stability. Innovation and design of solid materials for environmental applications and clean energy are key research focuses.

[0003] Many solid adsorbents with ideal properties have been developed, with porous solid adsorbents capable of capturing carbon dioxide on their surfaces. Porous solid adsorbents are mainly used for the physical adsorption of carbon dioxide from flue gas, exhaust gas, and even the air. Porous adsorbents have several advantages, including numerous active sites, low cost, large specific surface area, chemical stability, and low energy requirements for regeneration. Adsorbents can be regenerated by heating or depressurizing. However, existing adsorbents still suffer from low carbon dioxide adsorption efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a biomass carbon aerogel, its preparation method, and its application. The biomass carbon aerogel obtained by the method provided by this invention has a high adsorption efficiency for carbon dioxide.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing biomass carbon aerogel, comprising the following steps:

[0007] Mix corrugated paper and water to obtain a suspension;

[0008] The suspension was placed in a mold and filtered, solvent was replaced with anhydrous ethanol, and after standing and molding, it was dried to obtain a blank.

[0009] The embryo material was immersed in a phosphoric acid ethanol solution and activated by shaking, and then carbonized to obtain the biomass carbon aerogel.

[0010] Preferably, the mass ratio of the corrugated paper to water is 5:250 to 400.

[0011] Preferably, the phosphoric acid ethanol solution is obtained by mixing a phosphoric acid solution and ethanol;

[0012] The phosphoric acid solution has a mass concentration of 85%; the mass ratio of the raw material to the phosphoric acid solution is 5:10-15; and the ratio of the raw material to ethanol is 5g:100-150mL.

[0013] Preferably, the mixing is carried out under stirring conditions, and the stirring time is 6 to 10 hours.

[0014] Preferably, the oscillation activation time is 8 to 10 hours.

[0015] Preferably, the carbonization is carried out under a protective atmosphere.

[0016] Preferably, the carbonization includes performing a first carbonization and a second carbonization sequentially;

[0017] The temperature of the first carbonization is 250-300℃, and the holding time is 1 hour.

[0018] The second carbonization temperature is 800-900℃, and the holding time is 2 hours.

[0019] Preferably, the carbonization heating rate is 5°C / min.

[0020] The present invention also provides biomass carbon aerogel prepared by the preparation method described in the above technical solution.

[0021] This invention also provides the application of the biomass carbon aerogel described in the above technical solution as a carbon dioxide adsorbent.

[0022] This invention provides a method for preparing biomass carbon aerogel, comprising the following steps: mixing corrugated paper and water to obtain a suspension; filtering the suspension in a mold, performing solvent replacement with anhydrous ethanol, allowing it to stand and solidify, and then drying to obtain a preform; immersing the preform in a phosphoric acid ethanol solution for oscillation activation, followed by carbonization to obtain the biomass carbon aerogel. This invention uses corrugated paper from household waste as a precursor and phosphoric acid as an activator to prepare carbon aerogel materials through a sol-gel process, chemical activation, and high-temperature carbonization. This preparation method is simple, uses inexpensive and readily available raw materials, has a small environmental footprint, and is suitable for large-scale production. The prepared carbon aerogel material exhibits low density, high specific surface area, high micropore ratio, and good carbon dioxide adsorption performance. Furthermore, this invention can adjust the pore structure of the carbon aerogel by controlling the mass ratio of phosphoric acid to the precursor to improve its adsorption performance, showing great application potential in the field of carbon capture. Attached Figure Description

[0023] Figure 1 This is a photograph of the biomass carbon aerogel obtained in Example 1.

[0024] Figure 2 The carbon dioxide adsorption isotherm of the biomass carbon aerogel obtained in Example 1;

[0025] Figure 3 The carbon dioxide adsorption isotherm of the biomass carbon aerogel obtained in Example 2;

[0026] Figure 4 The carbon dioxide adsorption isotherm of the biomass carbon aerogel obtained in Example 3;

[0027] Figure 5 The image shows the carbon dioxide adsorption isotherm of the biomass carbon aerogel obtained in Comparative Example 1. Detailed Implementation

[0028] This invention provides a method for preparing biomass carbon aerogel, comprising the following steps:

[0029] Mix corrugated paper and water to obtain a suspension;

[0030] The suspension was placed in a mold and filtered, solvent was replaced with anhydrous ethanol, and after standing and molding, it was dried to obtain a blank.

[0031] The embryo material was immersed in a phosphoric acid ethanol solution and activated by shaking, and then carbonized to obtain the biomass carbon aerogel.

[0032] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0033] This invention mixes corrugated paper and water to obtain a suspension.

[0034] This invention does not impose any special limitation on the size of the corrugated paper; any size well-known to those skilled in the art can be used. Prior to mixing, this invention preferably includes a crushing process on the corrugated paper; the crushing time is preferably 3 seconds; the crushing process is preferably carried out in a crusher. In this invention, the water is preferably deionized water.

[0035] In this invention, the mass ratio of corrugated paper to water is preferably 5:250-400, more preferably 5:300-350. In this invention, the mixing is preferably carried out under stirring conditions, and the stirring time is preferably 6-10 hours. In this invention, the stirring is preferably magnetic stirring.

[0036] After obtaining the suspension, the present invention places the suspension in a mold for filtration, uses anhydrous ethanol for solvent replacement, allows it to stand and form, and then dries it to obtain a blank.

[0037] In this invention, the filter cloth used for filtration preferably has a pore size of 300 mesh. This invention does not impose any particular limitation on the solvent replacement process; any process well-known to those skilled in the art can be used. In a specific embodiment of this invention, the solvent replacement process is preferably as follows: 300 mL of anhydrous ethanol is placed in a mold to replace the water in the sample.

[0038] In this invention, the drying method is preferably natural drying at room temperature and pressure; the drying time is preferably 4 to 8 hours.

[0039] After obtaining the preform, the present invention impregnates the preform in a phosphoric acid ethanol solution for oscillation activation, and then carbonizes it to obtain the biomass carbon aerogel.

[0040] In this invention, the phosphoric acid ethanol solution is preferably obtained by mixing a phosphoric acid solution and ethanol; the mass concentration of the phosphoric acid solution is preferably 85%; the mass ratio of the raw material to the phosphoric acid solution is preferably 5:10-15; and the amount ratio of the raw material to ethanol is preferably 5g:100-150mL.

[0041] After the oscillation activation, the present invention preferably includes drying the obtained billet, wherein the drying method is preferably natural drying at room temperature and pressure; and the drying time is preferably 4 to 8 hours.

[0042] In this invention, the carbonization is preferably carried out under a protective atmosphere, preferably nitrogen. In this invention, the carbonization is preferably carried out in a tubular furnace.

[0043] In this invention, the carbonization preferably includes sequentially performing a first carbonization and a second carbonization; the temperature of the first carbonization is preferably 250–300°C, and the holding time is preferably 1 hour; the temperature of the second carbonization is preferably 800–900°C, and the holding time is preferably 2 hours. In this invention, the heating rate of the carbonization is preferably 5°C / min.

[0044] This invention also provides a biomass carbon aerogel prepared by the preparation method described above. In this invention, the specific surface area of ​​the biomass carbon aerogel is preferably 1200 m². 2 The total pore volume of the biomass carbon aerogel is preferably 0.6 mL / g or more; the micropore volume of the biomass carbon aerogel is preferably 0.4 mL / g or more; the average pore size of the biomass carbon aerogel is preferably 2.0 nm or more; and the micropore content of the biomass carbon aerogel is preferably 74% or more.

[0045] This invention also provides the application of the biomass carbon aerogel described in the above technical solution as a carbon dioxide adsorbent. The specific implementation of this application is not particularly limited, and any method well known to those skilled in the art can be used. In this invention, the adsorption capacity of the biomass carbon aerogel for carbon dioxide is preferably 1.9 mmol / g or higher.

[0046] To further illustrate the present invention, a biomass carbon aerogel, its preparation method, and its application are described in detail below with reference to the accompanying drawings and embodiments. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0047] Example 1

[0048] Mix 5g of crushed corrugated paper with 300mL of deionized water and stir on a magnetic stirrer for 6 hours to obtain a suspension.

[0049] The suspension was poured into a mold and filtered through a 300-mesh filter cloth until no water droplets fell. 300 mL of anhydrous ethanol was poured into the mold to replace the water in the sample. After the sample was formed, it was removed and dried at room temperature and pressure for 4 hours to obtain the blank.

[0050] The embryo was soaked in a mixture of 12.5g of 85wt% phosphoric acid solution and 150mL of anhydrous ethanol and activated by shaking on a shaker for 8h.

[0051] The activated sample was dried at room temperature and pressure for 6 hours to obtain the activated billet.

[0052] The activated billet was placed in a tube furnace and heated to 300°C at a heating rate of 5°C / min under a nitrogen atmosphere. It was held for 1 hour and then heated to 800°C at a heating rate of 5°C / min. It was held for 2 hours to obtain biomass carbon aerogel.

[0053] The physical image of the biomass carbon aerogel obtained in this embodiment is shown below. Figure 1 As shown.

[0054] Example 2

[0055] Mix 5g of crushed corrugated paper with 300mL of deionized water and stir on a magnetic stirrer for 6 hours to obtain a suspension.

[0056] The suspension was poured into a mold and filtered through a 300-mesh filter cloth until no water droplets fell. 300 mL of anhydrous ethanol was poured into the mold to replace the water in the sample. After the sample was formed, it was removed and dried at room temperature and pressure for 4 hours to obtain the blank.

[0057] The embryo was soaked in a mixture of 10g of 85wt% phosphoric acid solution and 150mL of anhydrous ethanol and activated by shaking on a shaker for 8h.

[0058] The activated sample was dried at room temperature and pressure for 6 hours to obtain the activated billet.

[0059] The obtained billet was placed in a tube furnace and heated to 300°C at a heating rate of 5°C / min under a nitrogen atmosphere. The temperature was held for 1 hour, and then heated to 800°C at a heating rate of 5°C / min. The temperature was held for 2 hours to obtain biomass carbon aerogel.

[0060] Example 3

[0061] Mix 5g of crushed corrugated paper with 300mL of deionized water and stir on a magnetic stirrer for 6 hours to obtain a suspension.

[0062] The suspension was poured into a mold and filtered through a 300-mesh filter cloth until no water droplets fell. 300 mL of anhydrous ethanol was poured into the mold to replace the water in the sample. After the sample was formed, it was removed and dried at room temperature and pressure for 4 hours to obtain the blank.

[0063] The embryo was soaked in a mixture of 15g of 85wt% phosphoric acid solution and 150mL of anhydrous ethanol and activated by shaking on a shaker for 8h.

[0064] The shaken sample was dried at room temperature and pressure for 6 hours to obtain the activated billet.

[0065] The obtained billet was placed in a tube furnace and heated to 300°C at a heating rate of 5°C / min under a nitrogen atmosphere. The temperature was held for 1 hour, and then heated to 800°C at a heating rate of 5°C / min. The temperature was held for 2 hours to obtain biomass carbon aerogel.

[0066] Comparative Example 1

[0067] Mix 5g of crushed corrugated paper with 300mL of deionized water and stir on a magnetic stirrer for 6 hours to obtain a suspension.

[0068] The suspension was poured into a mold and filtered through a 300-mesh filter cloth until no water droplets fell. 300 mL of anhydrous ethanol was poured into the mold to replace the water in the sample. After the sample was formed, it was removed and dried at room temperature and pressure for 4 hours to obtain the blank.

[0069] The obtained billet was placed in a tube furnace and heated to 300°C at a heating rate of 5°C / min under a nitrogen atmosphere. The temperature was held for 1 hour, and then heated to 800°C at a heating rate of 5°C / min. The temperature was held for 2 hours to obtain biomass carbon aerogel.

[0070] Performance testing

[0071] The properties of the biomass carbon aerogels obtained in Examples 1-3 and Comparative Example 1 were characterized, and the results are shown in Table 1. Figures 2-5 The carbon dioxide adsorption isotherms of the biomass carbon aerogels obtained in Examples 1-3 and Comparative Example 1 are respectively.

[0072] Table 1. Performance characterization results of biomass carbon aerogels obtained in Examples 1-3 and Comparative Example 1

[0073] <![CDATA[BET specific surface area / m 2 ·g -1 > 1212.587 1173.098 1070.783 257.173 <![CDATA[Total pore volume / mL·g -1 > 0.6226 0.5586 0.5788 0.1867 <![CDATA[Micropore volume / mL·g -1 > 0.4652 0.4499 0.4001 0.0858 Average pore size / nm 2.0538 1.9047 2.1622 2.9039 Micropore percentage / % 74.72 80.54 69.13 45.96 <![CDATA[CO2 adsorption capacity]]> 1.903 1.5714 1.719 1.3529

[0074] The table above shows that the BET specific surface area, total pore volume, and micropore ratio of the phosphoric acid-modified biomass carbon aerogel are significantly increased. A positive correlation exists between the specific surface area of ​​the carbon aerogel and its carbon dioxide adsorption capacity. A larger surface area provides more active sites for carbon dioxide adsorption via physical adsorption. Therefore, a higher specific surface area of ​​the carbon aerogel should result in a greater carbon dioxide adsorption capacity. Pore volume and pore size also play a crucial role in carbon dioxide adsorption. Volatile matter is released from the carbon skeleton of the raw material, leading to the formation of a porous structure in the carbon aerogel. A larger total pore volume provides more active sites for the interaction between carbon dioxide and the carbon aerogel. Typically, the carbon dioxide capture capacity of carbon aerogel strongly depends on the presence of micropores, as the kinetic diameter of carbon dioxide is around 0.33 nm. Studies have shown that at low partial pressures, pores with a diameter of 0.5 nm or smaller significantly contribute to carbon dioxide adsorption, while pores with a diameter less than 0.8 nm contribute even more to carbon dioxide absorption at 1 bar. The ability to adsorb carbon dioxide is more strongly correlated with the micropore volume ratio and specific surface area, indicating that the microporous structure of carbon aerogel has a significant impact on the adsorption capacity of carbon dioxide.

[0075] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing biomass carbon aerogel, characterized in that, Includes the following steps: Mix corrugated paper and water to obtain a suspension; The suspension was placed in a mold and filtered, solvent was replaced with anhydrous ethanol, and after standing and molding, it was dried to obtain a blank; the drying was natural drying at room temperature and pressure. The preform is immersed in a phosphoric acid ethanol solution and activated by shaking, and then carbonized to obtain the biomass carbon aerogel; the phosphoric acid ethanol solution is obtained by mixing phosphoric acid solution and ethanol; the mass concentration of the phosphoric acid solution is 85%; the mass ratio of the preform to the phosphoric acid solution is 5:10-15; the amount ratio of the preform to ethanol is 5g:100-150mL. The biomass carbon aerogel has a micropore ratio of over 74%; The biomass carbon aerogel is used to adsorb carbon dioxide.

2. The production method according to claim 1, characterized by, The mass ratio of corrugated paper to water is 5:250 to 400.

3. The preparation method according to claim 1, characterized in that, The mixing is carried out under stirring conditions for 6 to 10 hours.

4. The preparation method according to claim 1, characterized in that, The oscillation activation time is 8–10 hours.

5. The preparation method according to claim 1, characterized in that, The carbonization is carried out under a protective atmosphere.

6. The production method according to claim 1 or 5, characterized by, The carbonization includes performing a first carbonization and a second carbonization sequentially. The temperature of the first carbonization is 250-300℃, and the holding time is 1 hour. The second carbonization temperature is 800-900℃, and the holding time is 2 hours.

7. The preparation method according to claim 6, characterized in that, The carbonization heating rate is 5°C / min.

8. Biomass carbon aerogel prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the biomass carbon aerogel according to claim 8 as a carbon dioxide adsorbent.

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