Method for preparing carbon microspheres by recovering waste biomass-based resin based on hydrothermal method

Abstract

The invention discloses a method for preparing carbon microspheres by recovering waste biomass-based resin based on a hydrothermal method, and belongs to the field of waste resin recovery and carbon microsphere preparation and synthesis. The dicyclopentadiene phenol resin is used for replacing part of resorcinol, the size of the microspheres is controlled by utilizing the characteristic of large molecular weight of the resin, finally, the carbon microspheres modified by the recycled resin have relatively good sphericity and smaller particle size, the preparation method is simple, and the reaction conditions are mild.

Description

Technical Field

[0001] This invention belongs to the field of waste resin recycling and carbon microsphere preparation and synthesis, specifically relating to a method for preparing carbon microspheres based on hydrothermal recycling of waste biomass-based resin, particularly relating to the recycling method of biomass-based resin and the preparation methods of related carbon microsphere precursors and carbon microspheres. Background Technology

[0002] Carbon microspheres are carbon-based nano / micron-sized materials with spherical or near-spherical structures, typically ranging in size from tens of nanometers to hundreds of micrometers. Their primary chemical composition is carbon, with trace amounts of impurity elements. Due to their good electrical conductivity, they are commonly used in electrochemical fields; furthermore, due to their stable chemical structure and relatively high specific surface area, they are frequently used for surface modification to support other functional materials.

[0003] Dicyclopentadiene phenol resin is a thermoplastic resin widely used in paints, inks, and electronic packaging materials. However, due to the environmental pollution caused by waste resin disposal, it does not meet the requirements of green chemistry. Therefore, relatively green and economically valuable waste resin recycling technologies are needed.

[0004] In the current era of pursuing green synthesis and chemical economy, the use of waste biomass dicyclopentadiene phenol resin as a raw material for the synthesis of microspheres is proposed, which not only meets the relevant requirements of green chemistry, but also helps to enhance the relevant value of waste resin. Summary of the Invention

[0005] In view of the aforementioned background problems, this invention proposes a method for preparing carbon microspheres by partially replacing resorcinol with waste biomass-based resin. Waste biomass-based resin can not only effectively replace resorcinol in the reaction, but also improve the size of the microspheres. Since waste biomass-based resin is a macromolecule, it can effectively reduce the diameter of the microspheres generated during the reaction, thus meeting the current requirements of green chemistry and environmental protection.

[0006] To improve the recycling of biomass-based resins, this invention provides a method for synthesizing recycled resin carbon microspheres using waste biomass dicyclopentadiene phenol resin as raw material and employing a two-step method of hydrothermal reaction and calcination. The specific steps are as follows: (1) Provide an ethanol solution of sodium hydroxide with a concentration of 1 mol / L. The pH of this solution is alkaline. Dissolve the waste biomass-based resin under alkaline conditions. Add a certain amount of waste dicyclopentadiene phenol resin to the ethanol solution of sodium hydroxide and stir at 35°C for more than 30 minutes to fully dissolve the waste biomass-based resin, thereby obtaining a waste dicyclopentadiene phenol resin solution, i.e., the recycled resin solution.

[0007] (2) Distilled water, waste dicyclopentadiene phenol resin solution, ammonia as an alkaline catalyst, resorcinol and sodium chloride as demulsifiers are added to a polytetrafluoroethylene liner sleeve. After mixing evenly, formaldehyde is added and mixed thoroughly to obtain a mixed solution. The mixed solution is subjected to hydrothermal reaction at 80~140°C for 24 hours. After the reaction is completed, it is centrifuged, washed and dried to obtain recycled resin microspheres.

[0008] (3) The obtained recycled resin microspheres are loaded into a stone boat, and the stone boat is placed in a tube furnace and calcined in a nitrogen atmosphere to obtain the recycled resin carbon microsphere product.

[0009] The mass ratio of waste dicyclopentadiene phenol resin to resorcinol is 4:0.5~2.5; preferably, the mass ratio of waste dicyclopentadiene phenol resin to resorcinol is 4:1, that is, resorcinol accounts for 20% of the total mass of phenol.

[0010] The amount of alkaline catalyst used is 0.9% to 1% of the mass of the reactants; the catalyst used in this invention is ammonia water with a mass fraction of 25%.

[0011] Adding sodium chloride as a demulsifier can reduce the aggregation of microspheres and achieve demulsification without damaging the morphology of the microspheres. The concentration of sodium chloride in the mixed solution is 2~3 mg / mL, preferably 2.3~2.5 mg / mL.

[0012] Formaldehyde is added according to the total amount of phenol reactants, where n 总反应物 :n 甲醛 =1:1.5.

[0013] Furthermore, in step (2), the volume ratio of distilled water to waste dicyclopentadiene phenol resin solution is 3:1.

[0014] Furthermore, in step (2), the hydrothermal reaction temperature is preferably 100°C and the reaction time is 24h.

[0015] Furthermore, distilled water was used for washing using a centrifuge, and the drying temperature was set at 60°C for 4 hours.

[0016] Furthermore, in the roasting process of step (3), an oxygen-free environment is provided by N2 gas flow, the temperature is set to 700℃~900℃, the heating time is 0.5~1h, and the holding time is 5~8h; preferably, the roasting temperature is 700~800℃ and the roasting time is 6h.

[0017] This invention uses waste biomass dicyclopentadiene phenol resin as a substitute for resorcinol in the synthesis of carbon microsphere precursors from recycled resin. Using this material to replace resorcinol reduces the amount of resorcinol used, thereby reducing related pollution. Simultaneously, it solves the problem of recycling and treating dicyclopentadiene phenol resin, effectively providing a treatment technology for dicyclopentadiene phenol resin, thus achieving multi-level resource utilization and realizing green chemistry. Furthermore, since biomass-based resin is a macromolecule, its relatively large volume during reaction effectively reduces the particle size of carbon microspheres and increases their specific surface area during the synthesis of waste resin microsphere precursors. Using a hydrothermal reaction for the synthesis of waste resin microsphere precursors effectively ensures the sphericity of the microspheres; adjusting the amount of sodium chloride further enhances the sphericity. This invention features mild reaction conditions, simple operation, and, due to the use of waste dicyclopentadiene phenol resin as a reactant, offers better economic benefits compared to traditional reactions. Attached Figure Description

[0018] Figure 1 SEM image (200 nm) of the carbon microspheres prepared in Example 1. Figure 2 SEM image (200 nm) of the carbon microspheres prepared in Example 2. Figure 3 SEM image (100 nm) of the carbon microspheres prepared in Example 3. Figure 4 SEM image (200 nm) of the carbon microspheres prepared in Example 4. Figure 5 SEM image (1 μm) of the carbon microspheres prepared in Example 5; Figure 6 SEM image (200 nm) of the carbon microspheres prepared in Comparative Example 1. Detailed Implementation

[0019] To enable those skilled in the art to better understand the invention, preferred embodiments of the invention will be described below in conjunction with specific examples, but these should not be construed as limiting the invention.

[0020] Unless otherwise specified, the experimental or testing methods described in the following embodiments are all conventional methods; unless otherwise specified, the reagents and materials are obtained from conventional commercial sources or prepared using conventional methods.

[0021] The waste biomass-based dicyclopentadiene phenol resin used in this invention is the biomass-based dicyclopentadiene phenol resin obtained by reacting dicyclopentadiene and phenol with modified lignin, as disclosed in Chinese Patent Publication No. CN118772378A.

[0022] The waste biomass-based dicyclopentadiene phenol resin solutions used in the following specific embodiments of the present invention were all prepared according to the following method: Add 0.1 mol of sodium hydroxide and 100 ml of anhydrous ethanol to a beaker equipped with a magnetic chalice to prepare a 1 mol / L sodium hydroxide ethanol solution; take 1.2 g of waste biomass-based dicyclopentadiene phenol resin and add it to 30 mL of a 1 mol / L sodium hydroxide ethanol solution, stir and dissolve at 35°C for 30 min to obtain a waste resin solution with a concentration of 40 mg / mL.

[0023] Example 1

[0024] (1) Take 5 ml of the obtained waste resin solution and put it into a polytetrafluoroethylene (PTFE) lined sleeve. Add 5 ml of ethanol to dilute it, fixing the volume of the waste resin solution to 10 mL. At the same time, add 30 ml of distilled water, 0.0508 g of resorcinol, and 0.1 ml of 25 wt% ammonia water to the PTFE lined sleeve. Then add 0.11 ml of formaldehyde to the PTFE lined sleeve and stir thoroughly for 40 min. After stirring completely, put the PTFE lined sleeve into a stainless steel outer sleeve, seal it tightly, and place it in a 100°C oven for 24 h. After the reaction is complete, take out the reactants, wash them with distilled water and centrifuge, and dry them in a 60°C oven for 4 h.

[0025] (2) The dried waste resin precursor was placed in a stone boat, and the stone boat was placed in a tube furnace for roasting. The temperature was set at 700°C, the heating time was 30 min, and the roasting time was 6 h to obtain the waste resin carbon microsphere product.

[0026] Example 2

[0027] (1) Take 5 ml of the obtained waste resin solution and put it into a polytetrafluoroethylene (PTFE) lined sleeve. At the same time, add 30 ml of distilled water, 5 ml of ethanol, 0.0521 g of resorcinol, 0.1 ml of ammonia, and 0.1 g of sodium chloride to the PTFE lined sleeve and stir for 20 min. Then add 0.11 ml of formaldehyde to the PTFE lined sleeve and stir thoroughly for 40 min. After stirring completely, put the PTFE lined sleeve into a stainless steel outer sleeve, seal it tightly, and place it in an oven at 100°C for 24 h. After the reaction is complete, take out the reactants, wash them with distilled water and centrifuge, and dry them in an oven at 60°C for 4 h.

[0028] (2) The dried waste resin precursor was placed in a stone boat, and the stone boat was placed in a tube furnace for roasting. The temperature was set at 700°C, the heating time was 30 min, and the roasting time was 6 h to obtain the waste resin carbon microsphere product.

[0029] Example 3

[0030] (1) Take 3 ml of the obtained waste resin solution and put it into a polytetrafluoroethylene (PTFE) lined sleeve. At the same time, add 30 ml of distilled water, 7 ml of ethanol, 0.0774 g of resorcinol, 0.1 ml of ammonia, and 0.1 g of sodium chloride to the PTFE lined sleeve and stir for 20 min. Then add 0.11 ml of formaldehyde to the PTFE lined sleeve and stir thoroughly for 40 min. After stirring completely, put the PTFE lined sleeve into a stainless steel outer sleeve, seal it tightly, and place it in an oven at 100°C for 24 h. After the reaction is complete, take out the reactants, wash them with distilled water and centrifuge, and dry them in an oven at 60°C for 4 h.

[0031] (2) The dried waste resin precursor was placed in a stone boat, and the stone boat was placed in a tube furnace for roasting. The temperature was set at 700°C, the heating time was 30 min, and the roasting time was 6 h to obtain the waste resin carbon microsphere product.

[0032] Example 4

[0033] (1) Take 3 ml of the obtained waste resin solution and put it into a polytetrafluoroethylene (PTFE) lined sleeve. At the same time, add 30 ml of distilled water, 7 ml of ethanol, 0.0753 g of resorcinol, 0.1 ml of ammonia, and 0.1 g of sodium chloride to the PTFE lined sleeve and stir for 20 min. Then add 0.11 ml of formaldehyde to the PTFE lined sleeve and stir thoroughly for 40 min. After stirring completely, put the PTFE lined sleeve into a stainless steel outer sleeve, seal it tightly, and place it in an oven at 100°C for 24 h. After the reaction is complete, take out the reactants, wash them with distilled water and centrifuge, and dry them in an oven at 60°C for 4 h.

[0034] (2) The dried waste resin precursor was placed in a stone boat, and the stone boat was placed in a tube furnace for roasting. The temperature was set at 800°C, the heating time was 30 min, and the roasting time was 6 h to obtain the waste resin carbon microsphere product.

[0035] Example 5

[0036] (1) Take 5 ml of the obtained waste resin solution and put it into a polytetrafluoroethylene (PTFE) lined sleeve. At the same time, add 30 ml of distilled water, 5 ml of ethanol, 0.0532 g of resorcinol, 0.1 ml of ammonia, and 0.1 g of sodium chloride to the PTFE lined sleeve and stir for 20 min. Then add 0.11 ml of formaldehyde to the PTFE lined sleeve and stir thoroughly for 40 min. After stirring completely, put the PTFE lined sleeve into a stainless steel outer sleeve, seal it tightly, and place it in an oven at 100°C for 24 h. After the reaction is complete, take out the reactants, wash them with distilled water and centrifuge, and dry them in an oven at 60°C for 4 h.

[0037] (2) The dried waste resin precursor was placed in a stone boat, and the stone boat was placed in a tube furnace for roasting. The temperature was set at 800°C, the heating time was 30 min, and the roasting time was 6 h to obtain the waste resin carbon microsphere product.

[0038] Comparative Example 1

[0039] (1) Add 30 ml of distilled water, 10 ml of ethanol, 0.1212 g of resorcinol, and 0.1 ml of ammonia to the PTFE inner liner sleeve and stir for 20 min. Then add 0.11 ml of formaldehyde to the PTFE inner liner sleeve and stir thoroughly for 40 min. After stirring completely, place the PTFE inner liner sleeve into the stainless steel outer sleeve, seal and tighten it, and place it in an oven at 100°C for 24 h. After the reaction is complete, remove the reactants, wash them with distilled water and centrifuge, and dry them in an oven at 60°C for 4 h.

[0040] (2) The dried waste resin precursor was placed in a stone boat, and the stone boat was placed in a tube furnace for roasting. The temperature was set at 600°C, the heating time was 30 min, and the roasting time was 6 h to obtain the waste resin carbon microsphere product.

[0041] Comparative Example 2

[0042] (1) Take 5 ml of the obtained waste resin solution and put it into a polytetrafluoroethylene (PTFE) lined sleeve. At the same time, add 30 ml of distilled water, 5 ml of ethanol, 0.0508 g of resorcinol, 0.1 ml of ammonia, and 0.1 g of sodium chloride to the PTFE lined sleeve and stir for 20 min. Then add 0.11 ml of formaldehyde to the PTFE lined sleeve and stir thoroughly for 40 min. After stirring completely, put the PTFE lined sleeve into a stainless steel outer sleeve, seal it tightly, and place it in an oven at 100°C for 24 h. After the reaction is complete, take out the reactants, wash them with distilled water and centrifuge, and dry them in an oven at 60°C for 4 h.

[0043] (2) The dried waste resin precursor was placed in a stone boat, and the stone boat was placed in a tube furnace for roasting. The temperature was set at 600°C, the heating time was 30 min, and the roasting time was 6 h to obtain the waste resin carbon microsphere product.

[0044] Comparative Example 3

[0045] (1) Take 3 ml of the obtained waste resin solution and put it into a polytetrafluoroethylene (PTFE) lined sleeve. At the same time, add 30 ml of distilled water, 7 ml of ethanol, 0.0784 g of resorcinol, 0.1 ml of ammonia, and 0.1 g of sodium chloride to the PTFE lined sleeve and stir for 20 min. Then add 0.11 ml of formaldehyde to the PTFE lined sleeve and stir thoroughly for 40 min. After stirring completely, put the PTFE lined sleeve into a stainless steel outer sleeve, seal it tightly, and place it in an oven at 100°C for 24 h. After the reaction is complete, take out the reactants, wash them with distilled water and centrifuge, and dry them in an oven at 60°C for 4 h.

[0046] (2) The dried waste resin precursor was placed in a stone boat, and the stone boat was placed in a tube furnace for roasting. The temperature was set at 600°C, the heating time was 30 min, and the roasting time was 6 h to obtain the waste resin carbon microsphere product.

[0047] Electron microscopy images show that, compared to Comparative Example 1, the carbon microspheres prepared by partially replacing resorcinol with waste biomass-based dicyclopentadiene phenol resin in Example 1 have significantly smaller particle size and higher sphericity. In Example 2, the addition of sodium chloride as a demulsifier further reduced the particle size and improved sphericity. In Examples 3-5, adjusting the amount of resin or calcination conditions allowed for control of the microsphere particle size and sphericity. Comparative Examples 2 and 3, due to their lower calcination temperatures, exhibited some sphere adhesion, resulting in relatively poor sphericity and low overall regularity. Among the resins mentioned above, the examples of this invention have higher sphericity and particle size than the comparative examples. Example 2, in particular, has superior particle size and sphericity compared to the other groups, and its specific surface area, calculated using BET testing, is 1845 m². 2 / g. This indicates that it is feasible to prepare carbon microspheres using recycled waste dicyclopentadiene phenol resin, and that the sphericity and particle size of the carbon microspheres can be optimized.

[0048] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing recycled resin carbon microspheres, characterized by, The method comprises the following specific steps: (1) providing an ethanol solution of sodium hydroxide, adding waste dicyclopentadiene phenol resin into the ethanol solution of sodium hydroxide to dissolve sufficiently, and obtaining a recycled resin solution; (2) mixing the recycled resin solution, resorcinol, an alkali catalyst, a demulsifier and distilled water uniformly, adding formaldehyde and mixing uniformly to obtain a mixed solution; performing hydrothermal reaction, centrifugation, washing and drying to obtain recycled resin microspheres; (3) calcining the recycled resin microspheres in a nitrogen atmosphere to obtain recycled resin carbon microspheres.

2. The method for preparing recycled resin carbon microspheres according to claim 1, characterized in that, The concentration of sodium hydroxide in the ethanol solution of sodium hydroxide in step (1) is 1 mol / L.

3. The method for preparing recycled resin carbon microspheres according to claim 1, characterized in that, The alkali catalyst in step (2) is ammonia water, and the amount of ammonia water is 0.9-1% of the total amount of substances.

4. The method for preparing recycled resin carbon microspheres according to claim 1, characterized in that, The demulsifier is sodium chloride, and the concentration of sodium chloride in the mixed solution is 2-3 mg / mL.

5. The method for preparing recycled resin carbon microspheres according to claim 1, characterized in that, The mass ratio of waste dicyclopentadiene phenol resin to resorcinol is 4:0.5-2.

5.

6. The method for preparing recycled resin carbon microspheres according to claim 1, characterized in that, The amount of formaldehyde added is calculated based on the total amount of phenol reactants, n. 总反应物 :n 甲醛 =1:1.

5.

7. The method for preparing recycled resin carbon microspheres according to claim 1, characterized in that, The hydrothermal reaction temperature in step (2) is 80-140°C, and the reaction time is 24 h.

8. The method for preparing recycled resin carbon microspheres according to claim 1, characterized in that, The calcination temperature in step (3) is 700-900°C, and the holding time is 5-8 h.

9. The method for preparing recycled resin carbon microspheres according to claim 8, characterized in that, The calcination temperature in step (3) is 700-800°C, and the holding time is 6 h.

10. The method for preparing recycled resin carbon microspheres according to claim 1, characterized in that, The heating time of calcination in step (3) is 0.5-1 h.

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