A method for preparing hollow micro-nano carbon spheres by microwave-assisted heating of lignin

A microwave-assisted, lignin technology, applied in the field of waste resource utilization, can solve the problems of poor process controllability of carbon materials, difficult to control morphology, complex lignin structure, etc., and achieve good thermal stability, excellent electrical conductivity, The effect of high strength to weight ratio

Active Publication Date: 2021-06-18
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are few reports on the technology and method of producing hollow micro-nano carbon spheres by using lignin. This is due to the complex structure of lignin, the poor controllability of the preparation process of carbon materials and the difficulty in controlling the morphology.

Method used

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  • A method for preparing hollow micro-nano carbon spheres by microwave-assisted heating of lignin
  • A method for preparing hollow micro-nano carbon spheres by microwave-assisted heating of lignin
  • A method for preparing hollow micro-nano carbon spheres by microwave-assisted heating of lignin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Taking alkali lignin as an example to introduce the implementation process of the present invention is as follows:

[0031] Put 10 grams of lignin with a particle size of 10-150 μm in a microwave reactor, and then pass 400mL / min nitrogen gas for 20 minutes to eliminate the air in the microwave reaction system, then turn on the microwave reactor for microwave-assisted heating, and the microwave frequency is 2.45 GHz, the microwave power is 800W, and the corresponding heating rate is 50°C / min. After the temperature rises to 350°C, adjust the microwave power to 300W, and the corresponding heating rate is 10°C / min, raise the temperature to 600°C, keep warm for 60 minutes, and then shut down Microwave reactor, when the temperature in the system drops below 150°C, turn off the nitrogen, and sieve the obtained solid product through a 12500-mesh filter. The solid product that passes through the filter is hollow carbon nanospheres, and the solid product that does not pass through...

Embodiment 2

[0034] Taking lignosulfonate as an example to introduce the implementation process of the present invention is as follows:

[0035] Put 10 grams of lignin with a particle size of less than 90 μm in a microwave reactor, and then pass 1000 mL / min of argon gas for 10 minutes to remove the air in the microwave reaction system, then turn on the microwave reactor for microwave-assisted heating, and the microwave frequency is 2.45 GHz , the microwave power is 2000W, and the corresponding heating rate is 150°C / min. After the temperature rises to 550°C, adjust the microwave power to 800W, and the corresponding heating rate is 50°C / min, raise the temperature to 800°C, keep warm for 10 minutes, and then turn off the microwave Reactor, when the temperature in the system drops below 150°C, turn off the argon, and sieve the obtained solid product through a 12500-mesh filter. The solid product that passes through the filter is hollow carbon nanospheres, and the solid product that does not pas...

Embodiment 3

[0037] Taking kraft lignin, dealkalized lignin, and enzymatic lignin mixed lignin (the mixing mass ratio of the three is 1:3:2) as an example to introduce the implementation process of the present invention as follows:

[0038] Put 10 grams of mixed lignin with a particle size of less than 50 μm in a microwave reactor, and then pass 800 mL / min of nitrogen gas for 15 minutes to eliminate the air in the microwave reaction system, then turn on the microwave reactor for microwave-assisted heating, and the microwave frequency is 2.45 GHz , the microwave power is 1400W, and the corresponding heating rate is 100°C / min. After the temperature rises to 450°C, adjust the microwave power to 550W, and the corresponding heating rate is 30°C / min, raise the temperature to 700°C, keep warm for 20 minutes, and then turn off the microwave Reactor, when the temperature in the system drops below 150°C, turn off the nitrogen, and sieve the obtained solid product through a 12500 mesh filter. The soli...

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Abstract

The invention discloses a method for preparing hollow micro-nano carbon spheres by microwave assisted heating of lignin. Firstly, the lignin is placed in a microwave reactor, and then a carrier gas is passed through to remove the air therein; then the microwave reactor is turned on and kept loaded. The air flow rate is constant, and the temperature is raised to 350-550°C at a heating rate of 50-150°C / min, wherein the microwave power is 800-2000W; then the microwave power is adjusted to 300-800W, and the heating rate is 10-50°C / min. To 600-800°C, keep warm for 10-60 minutes; finally close the microwave reactor, keep the flow rate of the carrier gas constant, after cooling down to below 150°C, turn off the carrier gas, and the obtained solid product is hollow micro-nano carbon spheres. The invention will provide a new approach for high-value utilization of waste resource lignin, and is also expected to provide a new type of basic material for the field of carbon materials.

Description

technical field [0001] The invention belongs to the field of resource utilization of waste, and in particular relates to a method for preparing hollow micro-nano carbon spheres by microwave-assisted heating of lignin. Background technique [0002] Lignin is the main by-product in the process of pulping and papermaking and forest biomass refining, and its output is huge. Every year, the national pulping and papermaking industry and biomass refining industry produce more than 50 million tons of lignin, such as the alkali produced by caustic soda pulping Lignin, lignin sulfonate produced by sulfite pulping, kraft lignin produced by kraft pulping and enzymatic lignin produced by biorefinery ethanol, etc. These lignins are usually used for direct combustion or Treated as waste, the added value of utilization is low. [0003] Lignin is a three-dimensional natural polymer compound with both carbon chains and aromatic rings in its structure. It has a high carbon content and is an e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/05
CPCC01P2004/03C01P2004/34C01P2004/61C01P2006/12C01B32/05
Inventor 王文亮时宇杰党泽攀陈珊珊黄佳乐唐宁
Owner SHAANXI UNIV OF SCI & TECH
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