A method for producing graphene includes: a pretreatment process of drying and pulverizing a vegetable material to obtain a carbon source; a carbonization process of carbonizing the carbon source to obtain a carbide; and a purification process of removing an impurity containing silica from the carbide obtained in the carbonization process, wherein the carbonization process including a heating process of supplying an inert gas into a chamber and heating the carbon source in the chamber in a plasma atmosphere.

Provided are graphene nanosheets having a polyaromatic hydrocarbon concentration of less than about 0.7% by weight and a tap density of less than about 0.08 g/cm.sup.3, as measured by ASTM B527-15 standard. The graphene nanosheets also have a specific surface area (B.E.T) greater than about 250 m.sup.2/g. Also provided are processes for producing graphene nanosheets as well as for removing polyaromatic hydrocarbons from graphene nanosheets, comprising heating said graphene nanosheets under oxidative atmosphere, at a temperature of at least about 200° C.

Provided are graphene nanosheets having a polyaromatic hydrocarbon concentration of less than about 0.7% by weight and a tap density of less than about 0.08 g/cm.sup.3, as measured by ASTM B527-15 standard. The graphene nanosheets also have a specific surface area (B.E.T) greater than about 250 m.sup.2/g. Also provided are processes for producing graphene nanosheets as well as for removing polyaromatic hydrocarbons from graphene nanosheets, comprising heating said graphene nanosheets under oxidative atmosphere, at a temperature of at least about 200° C.

The present disclosure provides a method for repairing defect of graphene, including: firstly introducing a composite fluid containing a reactive compound and a supercritical fluid to a reactor where the graphene powder has been placed, and impregnating the graphene powder with the composite fluid to passivate and repair the defect of graphene, wherein the reactive compound includes carbon, hydrogen, nitrogen, silicon or oxygen element; and separating the composite fluid from the graphene powder, simultaneously using molecular sieves to absorb the graphene from the composite fluid. The present disclosure further provides the graphene powder prepared by the method above. With the method of the present disclosure, it effectively reduces the ratio of the defect of the graphene, increases the content of the graphene, and has less-layer graphene with high thermal conductivity and electrical conductivity.

A method and system of separating graphene nanoplatelets (GNPs) from initial graphite raw material is disclosed. The raw material is exfoliated to create a percentage of separated GNPs in a resulting bulk mixture. Agglomerates between the separated graphene nanoplatelets are broken. The mixture is separated into fractions having nanoparticles of different GNP content and size distribution. Each different range of nanoparticles is separated into GNPs and graphite nanopowder via a medium flow process or via electrostatic separation or both.

A method and system of separating graphene nanoplatelets (GNPs) from initial graphite raw material is disclosed. The raw material is exfoliated to create a percentage of separated GNPs in a resulting bulk mixture. Agglomerates between the separated graphene nanoplatelets are broken. The mixture is separated into fractions having nanoparticles of different GNP content and size distribution. Each different range of nanoparticles is separated into GNPs and graphite nanopowder via a medium flow process or via electrostatic separation or both.

The present invention relates to a scanning probe microscope. The scanning probe microscope can be configured to remove a polymeric material from a surface of a nanostructure. The scanning probe microscope includes a metal coated probe tip and a voltage source. The voltage source can be configured to apply a bias voltage between the probe tip and a sample. The bias voltage can be between 0.5 V and 2 V. The scanning probe microscope further includes a sample positioner configured to position the sample in relation to the probe tip and a system controller configured to control the scanning probe microscope.

The present invention relates to a scanning probe microscope. The scanning probe microscope can be configured to remove a polymeric material from a surface of a nanostructure. The scanning probe microscope includes a metal coated probe tip and a voltage source. The voltage source can be configured to apply a bias voltage between the probe tip and a sample. The bias voltage can be between 0.5 V and 2 V. The scanning probe microscope further includes a sample positioner configured to position the sample in relation to the probe tip and a system controller configured to control the scanning probe microscope.

A system and a method of continuously separating submicron thickness laminar solid particles from a solid suspension, segregating the suspension into a submicron thickness particle fraction suspension and a residual particle fraction suspension, the method comprising the steps of; providing a continuous centrifuge apparatus; providing a suspension of submicron thickness laminar solid particles in a solid suspension; wherein the solid suspension comprises the submicron thickness solid particles in a liquid continuous phase; separating the solid suspension in the apparatus.

A system and a method of continuously separating submicron thickness laminar solid particles from a solid suspension, segregating the suspension into a submicron thickness particle fraction suspension and a residual particle fraction suspension, the method comprising the steps of; providing a continuous centrifuge apparatus; providing a suspension of submicron thickness laminar solid particles in a solid suspension; wherein the solid suspension comprises the submicron thickness solid particles in a liquid continuous phase; separating the solid suspension in the apparatus.