Preparation method of carbon aerogel material suitable for adsorbing acidic gas

Abstract

The invention relates to the technical field of adsorption materials, and discloses a preparation method of a carbon aerogel material suitable for adsorbing acidic gases, and the preparation method specifically comprises the following steps: carrying out ultrasonic dispersion and centrifugation on carbon aerogel, calcium salt, copper salt and water, drying the precipitate, leaching with a mixed solution containing N, N '-carbonyldiimidazole and a surfactant, and drying to obtain metal carbon aerogel; then uniformly dispersing the metal carbon aerogel, a vinyl benzene-containing monomer, polyvinyl alcohol and a solvent under a stirring condition, adding an initiator solution, and after the reaction is finished, performing centrifugal drying and high-temperature heat treatment to obtain the adsorption type carbon aerogel material. Calcium oxide and copper oxide surrounded by a nitrogen-containing carbon framework are generated on carbon aerogel in situ, meanwhile, the inner surface and the outer surface of the carbon aerogel are covered with a benzene-containing polymer, an ordered carbon framework is obtained after heat treatment, and the adsorption performance of the carbon aerogel can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorption materials, and particularly relates to a preparation method of a carbon aerogel material suitable for adsorbing acidic gases. Background Art

[0002] With the acceleration of the industrialization and urbanization processes, the pollution problems of nitrogen oxides (NO x ) and sulfur oxides (SO x ) in the atmosphere are becoming increasingly severe. Among them, nitrogen dioxide (NO2) and sulfur dioxide (SO2), as the main pollutants, not only cause environmental problems such as acid rain and photochemical smog, but also pose direct hazards to the human respiratory system and the ecological system.

[0003] Traditional adsorption materials (such as activated carbon, zeolite, etc.) mainly rely on physical adsorption, with small adsorption capacity and poor selectivity. In addition, the molecules of NO2 and SO2 are relatively small, and in high-temperature and high-humidity environments, the adsorption effect will be further reduced. Carbon aerogel has a large specific surface area and rich pore characteristics, and has excellent adsorption performance for benzene-containing organic compounds, but usually has poor adsorption effects on NO2 and SO2. Therefore, developing an efficient preparation method of a carbon aerogel material suitable for adsorbing acidic gases is of great significance for the further application expansion of carbon aerogel materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a carbon aerogel material suitable for adsorbing acidic gases, and solve the problems of small adsorption capacity and poor selectivity of the current mainstream adsorption materials for sulfur dioxide and nitrogen dioxide adsorption.

[0005] To achieve the above purpose, the present application provides the following technical solutions: The present application discloses a preparation method of a carbon aerogel material suitable for adsorbing acidic gases: ultrasonically disperse carbon aerogel, calcium salt, copper salt, and water, centrifuge, dry the precipitate, and then wash it with a mixed solution containing N,N'-carbonyldiimidazole and a surfactant, and then dry it to obtain a metal carbon aerogel; subsequently, disperse the metal carbon aerogel, vinyl benzene-containing monomer, polyvinyl alcohol, and solvent evenly under stirring, add an initiator solution, centrifuge and dry after the reaction is completed, and perform high-temperature heat treatment to obtain an adsorption-type carbon aerogel material.

[0006] Preferably, the calcium salt is a water-soluble calcium salt, which can be one of calcium chloride, calcium formate, calcium nitrate, or calcium acetate; the copper salt is a water-soluble copper salt, which can be one of copper chloride, copper nitrate, or copper sulfate; the weight ratio of carbon aerogel, calcium salt, copper salt, and water is 1:(0.1~1):(0.3~1):(20~100).

[0007] Preferably, the molar concentration of N,N'-carbonyldiimidazole in the mixed solution is 0.1 - 0.5 mol / L.

[0008] Preferably, the surfactant is one of sodium dodecyl sulfate, polysorbate, and polyoxyethylene fatty acid ester; the mass concentration of the surfactant in the mixed solution is 0.005 - 0.05 g / L.

[0009] Preferably, the elution time is 0.5 - 1 h.

[0010] Preferably, the vinyl benzene-containing monomer is a substance with a vinyl group and at least two connected benzene rings in the molecular formula, which can be one of 1-vinylnaphthalene, 2-vinylnaphthalene, or 9-vinylanthracene; the solvent is one of N,N-dimethylformamide, methanol, or ethanol.

[0011] Preferably, the mass ratio of the metal carbon aerogel, vinyl benzene-containing monomer, polyvinyl alcohol, and solvent is 1:(0.1 - 0.5):(0.01 - 0.03):(10 - 50).

[0012] Preferably, the initiator solution is one of ammonium persulfate solution, potassium persulfate solution, or sodium persulfate solution, with a concentration of 0.02 - 0.05 mol / L, and the addition amount is 0.2 - 1 times the weight of the metal carbon aerogel.

[0013] Preferably, the high-temperature heat treatment method is: maintaining the temperature at 850 - 1000 °C for 1 - 3 h under a nitrogen atmosphere.

[0014] Preferably, the adsorptive carbon aerogel material is applicable to the adsorption of gaseous benzene series, sulfur dioxide, and nitrogen dioxide.

[0015] Advantages of the present invention: 1. By the method of this application, calcium oxide and copper oxide surrounded by a nitrogen-containing carbon framework can be in-situ generated on the carbon aerogel. The nitrogen-containing carbon framework can effectively improve the pore properties of the carbon aerogel and increase the proportion of micropores. Calcium oxide and copper oxide can enrich and remove sulfur dioxide and nitrogen dioxide in the polluted gas through surface adsorption and chemical adsorption. The synergistic effect of the two can effectively improve the adsorption performance of the carbon aerogel for sulfur dioxide and nitrogen dioxide.

[0016] 2. Through the polymerization reaction, the benzene-containing polymer is covered on the inner and outer surfaces of the carbon aerogel in the preparation method of this application. After heat treatment, the obtained ordered carbon skeleton can not only improve the structural stability of calcium oxide and copper oxide but also further increase the number and pore volume of the micropores of the carbon aerogel, thereby further improving the adsorption performance of the carbon aerogel. Description of the Drawings

[0017] Figure 1Schematic diagram of a preparation method of a carbon aerogel material applicable to adsorbing acidic gases in this application; Figure 2 Adsorption curves of the aerogel materials obtained in Example 1 and Comparative Examples 1-3. Specific implementation manners

[0018] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below through the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0019] As Figure 1 shown, a preparation method of a carbon aerogel material applicable to adsorbing acidic gases is disclosed: carbon aerogel, calcium salt, copper salt, and water are ultrasonically dispersed in a weight ratio of 1:(0.1~1):(0.3~1):(20~100), centrifuged, and the precipitate is dried and then rinsed with a mixed solution containing 0.1~0.5 mol / L N,N'-carbonyldiimidazole and 0.005~0.05 g / L surfactant for 0.5~1 h, and then dried to obtain a metal carbon aerogel; subsequently, under stirring, the metal carbon aerogel, vinyl benzene-containing monomer, polyvinyl alcohol, and solvent are dispersed evenly in a mass ratio of 1:(0.1~0.5):(0.01~0.03):(10~50), and an initiator solution of 0.02~0.05 mol / L with a weight 0.2~1 times that of the metal carbon aerogel is added. After the reaction is completed, it is centrifuged and dried, and kept at a temperature of 850~1000 °C for 1~3 h under a nitrogen atmosphere to obtain an adsorption-type carbon aerogel material.

[0020] The calcium salt is a water-soluble calcium salt, which can be one of calcium chloride, calcium formate, calcium nitrate, and calcium acetate; the copper salt is a water-soluble copper salt, which can be one of copper chloride, copper nitrate, and copper sulfate. The surfactant is one of sodium dodecyl sulfate, polysorbate, and polyoxyethylene fatty acid ester. The vinyl benzene-containing monomer is a substance containing a vinyl group and at least two connected benzene rings in the molecular formula, which can be one of 1-vinylnaphthalene, 2-vinylnaphthalene, and 9-vinylanthracene; the solvent is one of N,N-dimethylformamide, methanol, and ethanol. The initiator solution is one of ammonium persulfate solution, potassium persulfate solution, and sodium persulfate solution.

[0021] Example 1: This example adopts the following scheme The carbon aerogel, calcium chloride, copper chloride, and water were ultrasonically dispersed in a weight ratio of 1:0.1:0.3:20, centrifuged, and the precipitate was dried and then rinsed with a mixed solution containing 0.1 mol / L N,N'-carbonyldiimidazole and 0.005 g / L sodium dodecyl sulfate for 0.5 h, and then dried to obtain a metal carbon aerogel; subsequently, the metal carbon aerogel, 1-vinylnaphthalene, polyvinyl alcohol, and N,N-dimethylformamide were dispersed evenly in a mass ratio of 1:0.1:0.01:10 under stirring, and a 0.02 mol / L ammonium persulfate solution 0.2 times the weight of the metal carbon aerogel was added. After the reaction ended, it was centrifuged and dried, and maintained at 850 °C for 1 h under a nitrogen atmosphere to obtain an adsorption-type carbon aerogel material.

[0022] Example 2: The following scheme was adopted in this example The carbon aerogel, calcium formate, copper nitrate, and water were ultrasonically dispersed in a weight ratio of 1:1:1:100, centrifuged, and the precipitate was dried and then rinsed with a mixed solution containing 0.5 mol / L N,N'-carbonyldiimidazole and 0.05 g / L polysorbate for 1 h, and then dried to obtain a metal carbon aerogel; subsequently, the metal carbon aerogel, 2-vinylnaphthalene, polyvinyl alcohol, and methanol were dispersed evenly in a mass ratio of 1:0.5:0.03:50 under stirring, and a 0.05 mol / L potassium persulfate solution 1 time the weight of the metal carbon aerogel was added. After the reaction ended, it was centrifuged and dried, and maintained at 1000 °C for 3 h under a nitrogen atmosphere to obtain an adsorption-type carbon aerogel material.

[0023] Example 3: The following scheme was adopted in this example The carbon aerogel, calcium nitrate, copper sulfate, and water were ultrasonically dispersed in a weight ratio of 1:0.5:0.6:50, centrifuged, and the precipitate was dried and then rinsed with a mixed solution containing 0.3 mol / L N,N'-carbonyldiimidazole and 0.01 g / L polyoxyethylene fatty acid ester for 0.8 h, and then dried to obtain a metal carbon aerogel; subsequently, the metal carbon aerogel, 9-vinylanthracene, polyvinyl alcohol, and ethanol were dispersed evenly in a mass ratio of 1:0.3:0.02:30 under stirring, and a 0.4 mol / L sodium persulfate solution 0.5 times the weight of the metal carbon aerogel was added. After the reaction ended, it was centrifuged and dried, and maintained at 900 °C for 2 h under a nitrogen atmosphere to obtain an adsorption-type carbon aerogel material.

[0024] Example 4: The following scheme was adopted in this example Carbon aerogel, calcium acetate, copper nitrate, and water were ultrasonically dispersed at a weight ratio of 1:0.7:0.5:80, centrifuged, and the precipitate was dried and then rinsed with a mixed solution containing 0.3 mol / L N,N'-carbonyldiimidazole and 0.03 g / L sodium dodecyl sulfate for 0.8 h, and then dried to obtain metal carbon aerogel; subsequently, under stirring, the metal carbon aerogel, 1-vinylnaphthalene, polyvinyl alcohol, and N,N-dimethylformamide were dispersed evenly at a mass ratio of 1:0.2:0.03:50, and a 0.04 mol / L ammonium persulfate solution 0.7 times the weight of the metal carbon aerogel was added. After the reaction ended, it was centrifuged and dried, and kept at 950 °C for 2 h under a nitrogen atmosphere to obtain an adsorptive carbon aerogel material.

[0025] Comparative Example 1 This comparative example used untreated carbon aerogel.

[0026] Comparative Example 2 Carbon aerogel, calcium chloride, copper chloride, and water were ultrasonically dispersed at a weight ratio of 1:0.1:0.3:20, centrifuged, and the precipitate was dried and then rinsed with a mixed solution containing 0.1 mol / L N,N'-carbonyldiimidazole and 0.005 g / L sodium dodecyl sulfate for 0.5 h, and then dried to obtain metal carbon aerogel, which was kept at 850 °C for 1 h under a nitrogen atmosphere.

[0027] Comparative Example 3 Under stirring, carbon aerogel, 1-vinylnaphthalene, polyvinyl alcohol, and N,N-dimethylformamide were dispersed evenly at a mass ratio of 1:0.1:0.01:10, and a 0.02 mol / L ammonium persulfate solution 0.2 times the weight of the metal carbon aerogel was added. After the reaction ended, it was centrifuged and dried, and kept at 850 °C for 1 h under a nitrogen atmosphere.

[0028] Referring to GB / T 12496.5-1999 "Test Methods for Wood Activated Carbon - Determination of Carbon Tetrachloride Adsorption Rate (Activity)", the aerogel materials of Examples 1-4 and Comparative Examples 1-3 were subjected to sulfur dioxide and nitrogen dioxide adsorption experiments under the same test conditions to measure the saturated adsorption capacity of the materials.

[0029] The test results are shown in Table 1: Table 1 Summary of Test Results

[0030] From Table 1 and Figure 2It can be seen that, compared with Comparative Example 1, the saturated adsorption capacity and adsorption rate of Examples 1-4 and Comparative Examples 2-3 are both significantly improved, indicating that the carbon aerogel material prepared by the method of the present application can effectively improve the adsorption effect of sulfur dioxide and nitrogen dioxide. Further, the adsorption capacity of Examples 1-4 is greater than that of Comparative Example 3, mainly because the method of the present application can in-situ generate calcium oxide and copper oxide surrounded by a nitrogen-containing carbon framework on the carbon aerogel. The nitrogen-containing carbon framework can effectively improve the pore properties of the carbon aerogel and increase the proportion of micropores. Calcium oxide and copper oxide can enrich and remove sulfur dioxide and nitrogen dioxide in the polluted gas through surface adsorption and chemical adsorption. The synergistic effect of the two can effectively improve the adsorption performance of the carbon aerogel. The adsorption capacity of Examples 1-4 is greater than that of Comparative Example 3, mainly because the preparation method of the present application covers the inner and outer surfaces of the carbon aerogel with a benzene-containing polymer through a polymerization reaction. After heat treatment, the obtained ordered carbon skeleton can not only improve the structural stability of calcium oxide and copper oxide, but also further increase the number and pore volume of the micropores of the carbon aerogel, which can further improve the adsorption performance of the carbon aerogel.

[0031] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements or improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a carbon aerogel material suitable for adsorbing acidic gases, characterized in that, The preparation method is as follows: Ultrasonically disperse carbon aerogel, calcium salt, copper salt and water, then centrifuge. After drying the precipitate, wash it with a mixed solution containing N,N'-carbonyldiimidazole and surfactant, and then dry to obtain metal carbon aerogel. Subsequently, under stirring, disperse the metal carbon aerogel, vinyl benzene-containing monomer, polyvinyl alcohol and solvent evenly, add the initiator solution, centrifuge and dry after the reaction is completed, and then perform high-temperature heat treatment to obtain the adsorbent carbon aerogel material.

2. The preparation method of a carbon aerogel material applicable to adsorb acidic gases according to claim 1, wherein The calcium salt is a water-soluble calcium salt, which can be one of calcium chloride, calcium formate, calcium nitrate and calcium acetate; the copper salt is a water-soluble copper salt, which can be one of copper chloride, copper nitrate and copper sulfate; the weight ratio of carbon aerogel, calcium salt, copper salt and water is 1:(0.1~1):(0.3~1):(20~100).

3. The preparation method of a carbon aerogel material applicable to adsorbing acidic gases as described in claim 1, characterized in that The molar concentration of N,N'-carbonyldiimidazole in the mixed solution is 0.1~0.5 mol / L.

4. The preparation method of a carbon aerogel material applicable to adsorbing acidic gases according to claim 1, characterized in that, The surfactant is one of sodium dodecyl sulfate, polysorbate and polyoxyethylene fatty acid ester; the mass concentration of the surfactant in the mixed solution is 0.005~0.05 g / L.

5. The preparation method of a carbon aerogel material applicable to adsorbing acidic gases according to claim 1, characterized in that, The washing time is 0.5~1 h.

6. The preparation method of a carbon aerogel material applicable to adsorbing acidic gases as described in claim 1, characterized in that, The vinyl benzene-containing monomer is a substance with a vinyl group and at least two connected benzene rings in its molecular formula, which can be one of 1-vinylnaphthalene, 2-vinylnaphthalene and 9-vinylanthracene; the solvent is one of N,N-dimethylformamide, methanol and ethanol.

7. The preparation method of a carbon aerogel material applicable to adsorbing acidic gases as described in claim 1, characterized in that, The mass ratio of metal carbon aerogel, vinyl benzene-containing monomer, polyvinyl alcohol and solvent is 1:(0.1~0.5):(0.01~0.03):(10~50).

8. The preparation method of a carbon aerogel material applicable to adsorbing acidic gases as described in claim 1, characterized in that, The initiator solution is one of ammonium persulfate solution, potassium persulfate solution and sodium persulfate solution, with a concentration of 0.02~0.05 mol / L, and the addition amount is 0.2~1 times the weight of the metal carbon aerogel.

9. The preparation method of a carbon aerogel material applicable to adsorb acidic gases according to claim 1, characterized in that, The high-temperature heat treatment method is as follows: Keep the temperature at 850~1000 °C for 1~3 h under a nitrogen atmosphere.

10. The preparation method of a carbon aerogel material applicable to adsorbing acidic gases according to claim 1, characterized in that, The adsorbent carbon aerogel material is suitable for the adsorption of gaseous benzene series, sulfur dioxide and nitrogen dioxide.

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