Preparation method of graphene
Technical Field
The invention relates to the field of new materials, in particular to the technical field of graphene, and more particularly relates to a method for industrially preparing graphene.
Background
Graphene is a novel planar two-dimensional carbon material, has unique structural characteristics and excellent mechanical, electrical, optical and thermal properties, and has wide application prospects in the fields of nano-electronic devices, energy storage materials, catalysis, sensors, drug carriers, functional composite materials and the like. In addition, the graphene has great application prospects in the fields of bioengineering and medicine, including targeted drug delivery, cell imaging, biological detection, tumor treatment and the like. However, the existing preparation technology and cost of graphene limit the application and development of graphene.
Due to the excellent physical and chemical properties of graphene, the graphene has great application prospects and requirements in the fields of energy, chemical engineering, materials, biotechnology, aerospace, electric vehicles and the like, so that the development of a novel graphene preparation method which is low in cost, high in yield, free of pollution and capable of realizing large-scale production is an urgent need for graphene industrialization.
Disclosure of Invention
In order to overcome the problems in the prior art, the invention provides a preparation method of graphene. The method has the advantages of low cost, good separation effect, environmental friendliness and large-scale production, and the prepared graphene has a large size, so the method has a very good application prospect.
The invention adopts the following technical scheme:
a method for industrially preparing graphene comprises the following steps:
mixing graphite and concentrated sulfuric acid to obtain a mixed solution, and carrying out high-energy ball milling on the mixed solution under the protection of Ar gas, wherein the rotating speed of a ball mill is 1200-1300 rpm in the high-energy ball milling process, and the ball milling time is 30-48 hours;
and after the ball milling is finished, separating, washing, filtering and drying to obtain the graphene.
The weight-volume ratio of the mass of the graphite to the concentrated sulfuric acid is 1: 50-1: 500 g/mL.
The mass concentration of the concentrated sulfuric acid is 75-98%.
The graphite is selected from crystalline flake graphite, expandable graphite or a product of anthracite sintered at the temperature of 1200-1300 ℃.
The mixed solution is also added with hydrogen peroxide with the mass concentration of 30-45%. The addition of the hydrogen peroxide can accelerate the ball milling process of the graphene, shorten the ball milling time to 10-15 hours and quickly obtain the high-quality graphene.
The separated graphene and sulfuric acid can be recycled, resources are saved, and graphite flakes are basically and completely stripped to form graphene.
The particle size of the large-size graphene prepared by the method is less than 5 mu m, and the graphene prepared by stripping by the method can also realize large-scale production. In the invention, high-concentration sulfuric acid and graphite are weighed according to a certain proportion and are mixed and then ball-milled. Sulfuric acid is used as an necessary intercalation agent for graphite stripping, and natural graphite flakes are effectively stripped through long-time sulfuric acid bath high-energy ball milling. The stripped graphene can float on the upper layer of a sulfuric acid solution due to the fact that the specific gravity becomes light, the graphene floating on the upper layer is collected, distilled water is added for washing, the incompletely separated graphene can be still located below the stripped graphene due to the fact that the specific gravity is heavy. High-quality graphene can float on the water surface, and the upper graphene layer finally obtained is the graphene with excellent quality through washing and separation. The residual graphite which is not completely separated can be recycled and subjected to ultrasonic separation again, a large amount of acid is not discharged basically in the whole process, and waste acid caused by introducing an oxidant is not generated, so that the method for preparing the large-size graphene with high efficiency, environmental protection, large scale and no pollution is realized.
The invention has the beneficial effects that:
the invention provides a method for industrially preparing graphene, wherein graphite and concentrated sulfuric acid are mixed according to a certain proportion and then are subjected to ball milling treatment to obtain graphene with excellent quality floating on an upper layer, and graphite which is not completely stripped sinks on a lower layer of a solution and can be recycled for further ball milling. The method has the advantages of repeated recycling of sulfuric acid, resource saving, avoidance of waste acid discharge and environmental friendliness. The method solves the problems of high cost, low efficiency, environmental pollution and incapability of industrial large-scale production in the existing graphene preparation technology. In addition, the invention provides a novel method for industrially preparing graphene.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
The preparation method of the graphene comprises the following steps:
(1) weighing 10g of flake graphite and 1L of concentrated sulfuric acid with the mass concentration of 80%, and mixing to form a mixed solution, wherein the volume ratio of the mass of the graphite flake to the concentrated sulfuric acid is 1:100 g/mL;
(2) putting the mixed solution of the graphite and the concentrated sulfuric acid into a high-energy ball mill, and performing ball milling for 38 hours at the rotating speed of 1200 revolutions per minute; after the ball milling is finished, graphene is obtained through separation, washing, filtering and drying, 7.6g of graphene is obtained, and the particle size of the graphene is smaller than 4 microns. The separated sulfuric acid is recycled after being collected.
Example 2
The preparation method of the graphene comprises the following steps:
(1) weighing 10g of anthracite sintered product at 1200 ℃ and 1L of concentrated sulfuric acid with the mass concentration of 98%, and mixing to form a mixed solution, wherein the volume ratio of the mass of the graphite flake to the concentrated sulfuric acid is 1:100 g/mL;
(2) putting the mixed solution of the graphite and the concentrated sulfuric acid into a high-energy ball mill, and performing ball milling for 38 hours at the rotating speed of 1200 revolutions per minute; and after the ball milling is finished, separating, washing, filtering and drying to obtain 8.2g of graphene, wherein the particle size of the graphene is less than 3 microns. The separated sulfuric acid is recycled after being collected.
Example 3
The preparation method of the graphene comprises the following steps:
(1) weighing 10g of anthracite sintered product at 1200 ℃ and 1L of concentrated sulfuric acid with the mass concentration of 70%, and mixing to form a mixed solution, wherein the volume ratio of the mass of the graphite flake to the concentrated sulfuric acid is 1:100 g/mL;
(2) putting the mixed solution of the graphite and the concentrated sulfuric acid into a high-energy ball mill, and performing ball milling for 38 hours at the rotating speed of 1200 revolutions per minute; after ball milling is finished, graphene is obtained through separation, washing, filtering and drying, 5.5g of graphene is obtained, and the particle size of the graphene is smaller than 8 microns. The separated sulfuric acid is recycled after being collected.
Example 4
The preparation method of the graphene comprises the following steps:
(1) weighing 10g of flake graphite and 1L of concentrated sulfuric acid with the mass concentration of 85%, and mixing to form a mixed solution, wherein the volume ratio of the mass of the graphite flake to the volume of the concentrated sulfuric acid is 1:100 g/mL;
(2) putting the mixed solution of the graphite and the concentrated sulfuric acid into a high-energy ball mill, and performing ball milling for 45 hours at the rotating speed of 1300 revolutions per minute; and after the ball milling is finished, separating, washing, filtering and drying to obtain 8.8g of graphene, wherein the particle size of the graphene is less than 8 microns. The separated sulfuric acid is recycled after being collected.
Example 5
The preparation method of the graphene comprises the following steps:
(1) weighing 10g of flake graphite and 1L of concentrated sulfuric acid with the mass concentration of 85%, and mixing to form a mixed solution, wherein the volume ratio of the mass of the graphite flake to the volume of the concentrated sulfuric acid is 1:100 g/mL;
(2) putting the mixed solution of the graphite and the concentrated sulfuric acid into a high-energy ball mill, adding 35% hydrogen peroxide by mass concentration, and performing ball milling for 10 hours at the rotating speed of 1300 r/min; and after the ball milling is finished, separating, washing, filtering and drying to obtain 9.3g of graphene, wherein the particle size of the graphene is less than 3 microns. The separated sulfuric acid is recycled after being collected.