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CN-122010085-A - Biomass tar-based mesophase carbon microsphere, and microfluidic preparation method and application thereof

CN122010085ACN 122010085 ACN122010085 ACN 122010085ACN-122010085-A

Abstract

The invention discloses a biomass tar-based mesophase carbon microsphere, a microfluidic preparation method and application thereof, and belongs to the technical field of environment-friendly carbon materials. The invention provides a microfluidic preparation method of biomass tar-based mesophase carbon microspheres for realizing high-value recycling of biomass tar, which comprises the steps of mixing biomass tar with an emulsifying solvent to obtain a tar internal phase solution, respectively injecting the tar internal phase solution and an external phase solution into a single-stage capillary microfluidic chip, shearing to obtain tar-based monodisperse micro-droplets, dripping into a receiving phase through a collecting pipe to form tar-based carbonaceous liquid crystal micro-droplets, performing hydrothermal carbonization to generate a layered carbonaceous mesophase, and then separating, cleaning and drying to obtain the biomass tar-based mesophase carbon microsphere. The invention utilizes the advantages of the biomass tar that the biomass tar is rich in aromatic compounds, oxygen-containing functional groups, nitrogen-containing functional groups and the like, adopts a microfluidic technology to regulate and control process conditions, promotes the preformation of lamellar carbonaceous liquid crystals under mild conditions, and has the advantages of high yield, mild liquid crystallization conditions and the like.

Inventors

  • JIN ZIHENG
  • ZHOU RUI
  • HE JINGLIN
  • JIANG XIA

Assignees

  • 四川大学

Dates

Publication Date
20260512
Application Date
20260122
Priority Date
20250124

Claims (10)

  1. 1. The microfluidic preparation method of the biomass tar-based mesophase carbon microsphere is characterized by comprising the following steps of: A. Mixing biomass tar and an emulsifying solvent to obtain a tar internal phase solution, respectively injecting the tar internal phase solution and an external phase solution into a single-stage capillary microfluidic chip, and shearing the tar internal phase solution into tar-based monodisperse micro-droplets through the shearing action of the external phase solution; B. C, dripping the tar monodisperse micro-droplets obtained in the step A into a receiving phase through a collecting pipe, and further depositing carbon to form tar-based carbonaceous liquid crystal micro-droplets; C. And C, heating the tar-based carbonaceous liquid crystal micro-droplets obtained in the step B to 200-450 ℃ for hydrothermal carbonization for 4-12 hours, carrying out planar aromatic macromolecule polycondensation and orderly orientation to generate a layered carbonaceous mesophase, and then separating, cleaning and drying to obtain the biomass tar-based mesophase carbon microsphere with a layered structure.
  2. 2. The microfluidic preparation method of biomass tar-based mesophase carbon microspheres according to claim 1, wherein in the step A, at least one of the following is satisfied: the emulsifying solvent is at least one of ethanol, toluene, benzene, carbon disulfide, DMF or chloroform; the mass concentration of biomass tar in the tar internal phase solution is 4-17%; the external phase solution is water or F127 water solution with the weight percent of 1-5%; When the single-stage capillary microfluidic chip is injected, controlling the flow rate of the internal phase solution of tar to be 0.5-3.0 mL/h, and controlling the flow rate of the external phase solution to be 20-50 mL/h, or controlling the flow rate of the external phase solution to be 5-50 mL/h.
  3. 3. The microfluidic preparation method of biomass tar-based mesophase carbon microspheres according to claim 1, wherein in the step A, at least one of the following is satisfied: The biomass tar is a semisolid byproduct generated by pyrolysis or gasification of at least one of straw, vinasse, rice hulls, wheat bran, yellow bamboo, wood bamboo, coconut shells, peanut shells or walnut shells; The single-stage capillary microfluidic chip comprises a glass capillary and a quartz square tube which are assembled on a glass slide, wherein an AB type epoxy adhesive is adopted to bond the conical end of the glass capillary and the quartz square tube to form a liquid drop cutting channel, wherein in the microfluidic chip, a tar internal phase solution channel is a glass capillary, the inner diameter of an inlet is 400-800 mu m, the outer diameter of the inlet is 800-1200 mu m, the inner diameter of an outlet conical end is 100-600 mu m, and the inner diameter of the outlet conical end is smaller than the inner diameter of the inlet; Injecting the tar internal phase solution and the external phase solution into the single-stage capillary microfluidic chip respectively by adopting an injection tube, wherein the inner diameter of the injection tube is 810-1210 mu m, and the inner diameter of the injection tube is consistent with the outer diameter of an inlet of a tar internal phase solution channel.
  4. 4. The microfluidic preparation method of biomass tar-based mesophase carbon microspheres according to claim 1, wherein in the step B, at least one of the following is satisfied: The collecting pipe is connected with the outlet end of the internal and external phase solution mixing channel, the inner diameter of the collecting pipe is 810-1210 mu m, and the inner diameter of the collecting pipe is matched with the outer diameter of the internal and external phase solution mixing channel; the length of the collecting pipe is 2-20 cm; The temperature of the collecting pipe is 0-150 ℃, preferably 0-80 ℃, and more preferably 0-60 ℃.
  5. 5. The microfluidic preparation method of biomass tar-based mesophase carbon microspheres according to claim 1, wherein in the step B, at least one of the following is satisfied: The receiving phase is water or F127 aqueous solution with the weight percent of 1-5%; in the dropping process, stirring the receiving phase at 200-1000 rpm; in the dropping process, the temperature of the receiving phase is 0 to 80 ℃, preferably 0 to 60 ℃, and more preferably 0 to 15 ℃.
  6. 6. The microfluidic preparation method of the biomass tar-based mesophase carbon microsphere according to claim 1, wherein in the step C, hydrothermal carbonization is performed for 4-8 hours at 180-330 ℃.
  7. 7. The microfluidic preparation method of biomass tar-based mesophase carbon microspheres according to claim 1, wherein in step C, at least one of the following is satisfied: The separation mode is centrifugation or filtration; the cleaning mode is that ethanol and water are adopted for cleaning until the cleaning solution is colorless; The drying mode is-50 to-90 ℃ and 0.01 to 0.1MPa freeze drying, 60 to 80 ℃ and 0.08 to 0.1MPa vacuum drying or 50 to 105 ℃ heating drying.
  8. 8. The biomass tar-based mesophase carbon microsphere prepared by the microfluidic preparation method of the biomass tar-based mesophase carbon microsphere according to any one of claims 1-7.
  9. 9. The biomass tar-based mesophase carbon microsphere as set forth in claim 8, wherein the particle size of the biomass tar-based mesophase carbon microsphere is 100-600 μm, and the biomass tar-based mesophase carbon microsphere has an anisotropy of flickering under polarized light.
  10. 10. The biomass tar-based mesophase carbon microsphere prepared by the microfluidic preparation method of the biomass tar-based mesophase carbon microsphere according to any one of claims 1-7, or the application of the biomass tar-based mesophase carbon microsphere according to claim 8-9 in preparation of lithium ion battery cathodes, carbon dioxide adsorption, hydrogen storage, hydrogen separation or low-carbon hydrocarbon separation.

Description

Biomass tar-based mesophase carbon microsphere, and microfluidic preparation method and application thereof Technical Field The invention belongs to the technical field of environment-friendly carbon materials, and particularly relates to a biomass tar-based mesophase carbon microsphere, a microfluidic preparation method and application thereof. Background Biomass tar is a black, high viscosity, pungent, semi-solid complex mixed byproduct produced during pyrolysis and gasification of biomass. The biomass tar is rich in aromatic compounds, has extremely high carbon content, can be fully mixed with an activating agent for pore forming due to higher viscosity and flowability, and can form a porous carbon material with large specific surface area, rich pore structure, high aroma and high stability after carbonization, thus being widely applied to various fields. CN117165315A discloses a continuous tar carbonization device and method, which uses a cylinder body with a continuous stirring mechanism to drive tar to flow and continuously carbonize, and activates carbonized gas based on CH 4、CO、CO2 and the like to prepare porous carbon materials. CN115215338a discloses a process system and a method for preparing porous carbon by carbonization and activation of biomass tar, the biomass tar and a cavitation agent are premixed, dried, carbonized and activated, and the obtained solid phase product is subjected to neutralization and water washing treatment to obtain the porous carbon. However, the above-mentioned process does not fully consider the properties of fluidity, self-polycondensation, strong anisotropy and easy graphitization of biomass tar under high temperature conditions, and simply directly carbonizes the tar under high temperature or directly carbonizes the tar after mixing with a pore etching agent. Because the tar is in a short-lasting state in high-temperature solid-phase carbonization and melting, aromatic ring molecules in biomass tar are subjected to pyrolysis and polycondensation, and then are subjected to disordered orientation, a final carbon net layer is in an irregular stack, the obtained tar derived carbon is of an amorphous carbon structure, the activity, stability and pore-forming potential of the tar derived carbon are lower than those of carbon materials with high graphitization degree, and the tar recycling efficiency is greatly reduced. In addition, the porous carbon material prepared by the process is in an irregular shape, and an additional forming process is needed in the subsequent application. The mesocarbon microbeads have a lamellar molecular parallel stacking structure, the activity, stability and pore-forming potential of which are far higher than those of the amorphous carbon materials, and meanwhile, the mesocarbon microbeads have the characteristics of sphere, have uniform particle size distribution and become a base material of a plurality of novel carbon materials. The biomass tar is similar to coal tar pitch and other components, is rich in aromatic compounds, and has the potential of preparing mesophase carbon microspheres. In addition, the biomass tar is unique to contain a large amount of oxygen-containing functional groups, nitrogen-containing functional groups and heteroatoms, and the oxygen-containing functional groups can promote the polycondensation of planar aromatic macromolecules at low temperature, accelerate the nucleation of a carbonaceous mesophase and prepare the mesophase carbon microsphere with higher yield. However, the heterogeneity of heteroatoms and nitrogen-containing functional groups may hinder ordered stacking of polycyclic aromatic hydrocarbons, forming a bridged disordered structure, and thus failing to form a carbonaceous liquid crystal. CN108840331a discloses a high-layer spacing artificial graphite material and a preparation method thereof, and CN108821275A discloses a high-capacity high-magnification graphite negative electrode material for lithium ion batteries and a preparation method thereof, wherein in the process of preparing mesophase carbon, a great number of functional groups such as aldehyde groups, carbonyl groups, hydroxyl groups and the like are arranged on aromatic rings of asphalt, and can be subjected to crosslinking reaction with aliphatic units and oxygen-containing groups in biomass tar under proper conditions, so that the polymerization degree of asphalt molecules is promoted, and polycondensation and crosslinking are carried out, so that the crosslinked mesophase carbon is obtained. However, the methods have low utilization rate of biomass tar (the ratio of asphalt to biomass tar is 100:3-30), severe crosslinking conditions, high temperature (350-550 ℃) and long time (10-24 hours). Under the background that a large amount of biomass tar needs to be recycled at a high value, the novel biomass tar-based intermediate phase carbon material with mild and stable liquid crystallization conditions and high yield is developed, and