Method for preparing hydrothermal carbon spheres from holocellulose
By adding persulfate to initiate a free radical graft copolymerization reaction during the hydrothermal carbonization of holocellulose, combined with one-step hydrothermal carbonization, the problems of low yield and insufficient surface functional groups in the preparation of hydrothermal carbon spheres from holocellulose were solved, achieving the preparation of hydrothermal carbon spheres with high yield and good morphology, exhibiting excellent adsorption performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANYING INT HLDG CO LTD
- Filing Date
- 2026-01-29
- Publication Date
- 2026-04-24
AI Technical Summary
In the existing technology, when preparing hydrothermal carbon spheres using a one-step hydrothermal method, the carbon sphere yield is low and the surface functional groups are insufficient, which is especially evident when using holocellulose as raw material.
Hydrothermal carbon spheres were prepared by using holocellulose as raw material and adding persulfate as an initiator through a one-step hydrothermal carbonization combined with free radical graft copolymerization. The specific steps include mixing holocellulose, unsaturated organic acid and persulfate, carrying out hydrothermal reaction, and then further activating in alkaline solution to obtain hydrothermal carbon spheres with high yield.
The yield of hydrothermal carbon spheres was increased by ≥50%, and the prepared carbon spheres had good spherical morphology and good adsorption performance.
Smart Images
Figure CN121913481A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of carbon sphere functional materials technology, and more specifically, to a method for preparing hydrothermal carbon spheres using holocellulose. Background Technology
[0002] Currently, the main technical approach for preparing hydrothermal carbon spheres is the one-step hydrothermal method for directly processing biomass. This technology uses raw biomass as raw material and directly carries out the hydrothermal carbonization reaction in a closed reactor. However, this method results in fewer grafted functional groups, a relatively low yield of hydrothermal carbon, and a small proportion of spherical spheres in the obtained hydrothermal carbon.
[0003] Rich in holocellulose, it is an excellent raw material for preparing hydrothermal carbon materials. Essentially, it is a lignocellulose enrichment after lignin removal. Therefore, it is foreseeable that it will also have problems such as low carbon ball yield and insufficient surface functional groups when preparing hydrothermal carbon balls. Summary of the Invention
[0004] 1. Technical problems to be solved This invention provides a method for preparing hydrothermal carbon spheres using holocellulose. Holocellulose is used as the raw material, and persulfate is added as an initiator. High-yield hydrothermal carbon sphere materials are prepared through a one-step hydrothermal carbonization combined with a free radical graft copolymerization reaction.
[0005] 2. Technical solutions adopted To achieve the above objectives, the technical solution provided by the present invention is as follows: This invention provides a method for preparing hydrothermal carbon spheres using holocellulose. The method includes: mixing holocellulose, unsaturated organic acid, and an initiator in an aqueous solution, and generating hydrothermal carbon spheres through a hydrothermal reaction; wherein the initiator used is persulfate, and the mass ratio of holocellulose to initiator is 50~100:1; the unsaturated organic acid used is selected from any one or any combination of two or more of methacrylic acid, acrylic acid, butenoic acid, and maleic acid.
[0006] Furthermore, the mass ratio of carboxyl groups in the holocellulose to those in the unsaturated organic acids is 8-20:1.
[0007] Furthermore, acrylic acid was chosen as the unsaturated organic acid used, and ammonium persulfate was chosen as the persulfate used.
[0008] Furthermore, the hydrothermal reaction time is 8~24h, and the reaction temperature is 150~200℃.
[0009] Furthermore, the hydrothermal reaction is carried out in a polytetrafluoroethylene reactor.
[0010] Furthermore, after the hydrothermal reaction apparatus has cooled down, the mixture is filtered, washed with water until neutral, and then dried to obtain dried hydrothermal carbon spheres.
[0011] Furthermore, the process includes the following steps: activating the dried hydrothermal carbon balls in an alkaline solution, filtering, and then washing until neutral to obtain the prepared hydrothermal carbon balls.
[0012] Furthermore, the ion concentration of hydroxide ions in the alkaline solution is 0.5~2 mol / L, the mass ratio of hydrothermal carbon to hydroxide ions in the alkaline solution is 1:1~2, the activation time is 40~80 min, and stirring is used as an auxiliary agent.
[0013] Furthermore, the yield of the prepared hydrothermal carbon spheres is ≥50%.
[0014] Compared with the prior art, the technical solution provided by this invention has the following advantages: This invention uses holocellulose as raw material, adding unsaturated organic acids and persulfates during its hydrothermal carbonization process. The persulfates act as initiators to generate free radicals, triggering a free radical graft copolymerization reaction. This is then combined with a one-step hydrothermal carbonization reaction to prepare high-yield hydrothermal carbon spheres, with a yield ≥50%. Furthermore, this preparation method is simple to operate, produces carbon spheres with good spherical morphology, and exhibits good adsorption properties. Attached Figure Description
[0015] Figure 1 This is a scanning electron microscope image of the hydrothermal carbon prepared in Comparative Example 1 of this invention.
[0016] Figure 2 This is a scanning electron microscope image of the hydrothermal carbon spheres prepared in Example 1 of the present invention. Detailed Implementation
[0017] To further understand the content of the present invention, the present invention will be described in detail with reference to embodiments and comparative examples.
[0018] The unsaturated organic acid used in the following examples is acrylic acid, which is only for detailed description of the technical solution of the present invention and should not be construed as a limitation on the specific types of unsaturated organic acids used in the method. The unsaturated organic acid used in this preparation method can also be any one of methacrylic acid, butenoic acid or maleic acid, or any combination of two or more of the above.
[0019] The persulfate used in the following examples is ammonium persulfate, which is only for detailed description of the technical solution of the present invention and should not be construed as a limitation on the type of persulfate used in the method. The persulfate in this preparation method can also be other persulfates besides ammonium persulfate.
[0020] Example 1 This embodiment provides a method for preparing hydrothermal carbon spheres using holocellulose, specifically including the following steps: S1. Take 1g of holocellulose and mix it with 10mL of water until homogeneous to obtain a mixed solution containing holocellulose.
[0021] S2. Add 0.1g of acrylic acid and 0.01g of ammonium persulfate to the mixed solution obtained in S1 and mix well to obtain a mixed solution to be hydrothermally heated. The 0.1g of acrylic acid used is equivalent to 0.0625g of the mass of its carboxyl groups. Place the mixed solution to be hydrothermally heated in a polytetrafluoroethylene reactor and hydrothermally react at 180℃ for 12h. After cooling, filter the obtained product, wash it with water until neutral, and then dry it to obtain hydrothermal carbon balls.
[0022] S3. Take 0.1g of the hydrothermal carbon balls obtained in S2 and disperse them in 20mL of 0.5mol / L KOH solution. Stir and activate for 60min. The mass of hydroxide ions in the KOH solution used is 0.17g. Filter and wash until neutral to obtain functionalized hydrothermal carbon.
[0023] The microstructure of the hydrothermal carbon spheres prepared in this embodiment is shown in the reference image. Figure 2 As shown, its sphericity is good.
[0024] After S2 is completed, the hydrothermal carbon yield is calculated using the following formula:
[0025] Where m0 is the mass of holocellulose raw material used in S1; m1 is the mass of hydrothermal carbon spheres obtained by drying in S2, and the yield of the obtained hydrothermal carbon spheres is detailed in Table 1.
[0026] Example 2 This embodiment provides a method for preparing hydrothermal carbon spheres using holocellulose, specifically including the following steps: S1. Take 1g of holocellulose and mix it with 8mL of water until homogeneous to obtain a mixed solution containing holocellulose.
[0027] S2. Add 0.08g of acrylic acid and 0.008g of ammonium persulfate to the mixed solution obtained in S1 and mix well to obtain a mixed solution to be hydrothermally heated. The 0.08g of acrylic acid used is equivalent to 0.05g of the mass of its carboxyl groups. Place the mixed solution to be hydrothermally heated in a polytetrafluoroethylene reactor and hydrothermally react at 170℃ for 11h. After cooling, filter the obtained product, wash it with water until neutral, and then dry it to obtain hydrothermal carbon balls.
[0028] S3. Take 0.1g of the hydrothermal carbon balls obtained in S2 and disperse them in 10mL of 1mol / L KOH solution. Stir and activate for 60min. The mass of hydroxide ions in the KOH solution used is 0.17g. Filter and wash until neutral to obtain functionalized hydrothermal carbon.
[0029] The microstructure of the hydrothermal carbon spheres prepared in this embodiment is similar to that in Example 1. The yield of the hydrothermal carbon spheres is detailed in Table 1.
[0030] Example 3 This embodiment provides a method for preparing hydrothermal carbon spheres using holocellulose, specifically including the following steps: S1. Take 1g of holocellulose and mix it with 20mL of water until homogeneous to obtain a mixed solution containing holocellulose.
[0031] S2. Add 0.2g of acrylic acid and 0.02g of ammonium persulfate to the mixed solution obtained in S1 and mix well to obtain a mixed solution to be hydrothermally heated. The 0.2g of acrylic acid used is equivalent to 0.125g of carboxyl groups. Place the mixed solution to be hydrothermally heated in a polytetrafluoroethylene reactor and hydrothermally react at 200℃ for 8 hours. After cooling, filter the obtained product, wash it with water until neutral, and then dry it to obtain hydrothermal carbon balls.
[0032] S3. Take 0.1g of the hydrothermal carbon balls obtained in S2 and disperse them in 20mL of 0.6mol / L KOH solution. Stir and activate for 60min. The mass of hydroxide ions in the KOH solution used is 0.20g. Filter and wash until neutral to obtain functionalized hydrothermal carbon.
[0033] The microstructure of the hydrothermal carbon spheres prepared in this embodiment is similar to that in Example 1. The yield of the hydrothermal carbon spheres is detailed in Table 1.
[0034] Comparative Example 1 This comparative example provides a method for preparing hydrothermal carbon using holocellulose, specifically including the following steps: S1. Take 1g of holocellulose and mix it with 10mL of water until homogeneous to obtain a mixed solution containing holocellulose.
[0035] S2. Place the mixed solution obtained in S1 in a polytetrafluoroethylene reactor and hydrothermally react at 180°C for 12 hours. After cooling, filter the product, wash it with water until neutral, and then dry it to obtain hot carbon.
[0036] The difference between this comparative example and Example 1 is that ammonium persulfate and acrylic acid are not added in S2, while the rest of the operations are basically the same.
[0037] The microstructure of the hydrothermal carbon prepared in this comparative example is shown in the reference image. Figure 1 As shown, its sphericity is relatively poor, and there are few carbon balls. The hydrothermal carbon yield is detailed in Table 1.
[0038] Performance testing The hydrothermal carbon balls prepared in Examples 1-3 and the hydrothermal carbon prepared in Comparative Example 1 were used as adsorbents for cationic pollutants. The specific test steps are as follows: 0.1 g of the product was placed in 200 mL of methylene blue solution with a concentration of 250 mg / L and adsorbed in a shaker at 30 °C for 48 h. The concentration of methylene blue was measured by ultraviolet spectrophotometer. The adsorption results are shown in Table 1.
[0039]
[0040] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.
Claims
1. A method for preparing hydrothermal carbon spheres using holocellulose, characterized in that, include: Hydrothermal carbon spheres are generated by mixing holocellulose, unsaturated organic acids and an initiator in an aqueous solution and reacting them through a hydrothermal reaction. The initiator used is persulfate, and the mass ratio of holocellulose to initiator is 50~100:
1. The unsaturated organic acid used is selected from any one or any combination of two or more of methacrylic acid, acrylic acid, butenoic acid and maleic acid.
2. The method for preparing hydrothermal carbon spheres using holocellulose according to claim 1, characterized in that, The mass ratio of holocellulose to carboxyl groups in unsaturated organic acids used is 8~20:
1.
3. The method for preparing hydrothermal carbon spheres using holocellulose according to claim 1, characterized in that, The unsaturated organic acid used was acrylic acid, and the persulfate used was ammonium sulfate.
4. The method for preparing hydrothermal carbon spheres using holocellulose according to claim 1, characterized in that, The hydrothermal reaction takes 8 to 24 hours and the reaction temperature is 150 to 200°C.
5. The method for preparing hydrothermal carbon spheres using holocellulose according to claim 4, characterized in that, The hydrothermal reaction is carried out in a polytetrafluoroethylene reactor.
6. The method for preparing hydrothermal carbon spheres using holocellulose according to claim 5, characterized in that, It also includes the following steps: After the hydrothermal reaction apparatus has cooled, the mixture is filtered, washed with water until neutral, and then dried to obtain dried hydrothermal carbon balls.
7. The method for preparing hydrothermal carbon spheres using holocellulose according to claim 6, characterized in that, It also includes the following steps: The dried hydrothermal carbon balls were activated in an alkaline solution, filtered, and then washed until neutral to obtain the prepared hydrothermal carbon balls.
8. The method for preparing hydrothermal carbon spheres using holocellulose according to claim 7, characterized in that, The concentration of hydroxide ions in the alkaline solution is 0.5~2 mol / L, the mass ratio of hydrothermal carbon to hydroxide ions in the alkaline solution is 1:1~2, the activation time is 40~80 min, and stirring is used as an auxiliary agent.
9. The method for preparing hydrothermal carbon spheres using holocellulose according to claim 7, characterized in that, The yield of the prepared hydrothermal carbon spheres is ≥50%.