The invention has for its object to provide an aqueous solution for structural separation capable of acting on carbon nanotubes (CNTs) having a specific structure thereby separating them with high accuracy, a separation and recovery method capable of allowing the aqueous solution to act on CNTs having a specific structure thereby separating and recovering them, and CNTs obtained by the separation and recovery method. According to the invention, it is possible to separate CNTs having a specific structure with high accuracy by solubilizing lithocholic acid or a lithocolic acid isomer that has high hydrophobicity and is insoluble in water by itself, and a carbon nanotube obtained by using an aqueous solution containing lithocholic acid or a lithocholic acid isomer, each solubilized, as an aqueous solution for structural separation of CNTs.

A low carbon footprint material is used to decrease the carbon dioxide emission for production of a high carbon footprint substance. A method of forming composite materials comprises providing a first high carbon footprint substance; providing a carbon nanomaterial produced with a carbon-footprint of less than 10 unit weight of carbon dioxide (CO.sub.2) emission during production of 1 unit weight of the carbon nanomaterial; and forming a composite comprising the high carbon footprint substance and from 0.001 wt % to 25 wt % of the carbon nanomaterial, wherein the carbon nanomaterial is homogeneously dispersed in the composite to reduce the carbon dioxide emission for producing the composite material relative to the high carbon footprint substance.

In the present invention, only low-growth carbon nanotubes are selectively separated among solid particles discharged during a reaction and then re-input to a reactor, so that it is possible to improve the quality of a carbon nanotube product to be produced and the productivity of a carbon nanotube production process.

A cross-linked structure of a carbon material is excellent in mechanical strength, such as tensile strength. The carbon materials such as carbon nanotube, graphite, fullerene, and carbon nanocoil, are cross-linked with each other. The carbon materials are cross-linked through a linking group derived from a nucleophilic compound having two or more nucleophilic groups in the molecule.

The present invention relates to a carbon nanotube fiber and methods for preparing the same. In one embodiment, a method for preparing a carbon nanotube fiber comprises reacting a carbon source in the presence of a catalyst and a catalytic activator to form carbon nanotube aggregates, contacting the carbon nanotube aggregates with graphene oxide, and forming the carbon nanotube aggregates in contact with the graphene oxide into a carbon nanotube fiber.

The present invention relates to a carbon nanotube composition including entangled-type carbon nanotubes and bundle-type carbon nanotubes, wherein the carbon nanotube composition has a specific surface area of 190 m.sup.2/g to 240 m.sup.2/g and a ratio of specific surface area to bulk density of 0.1 to 5.29.

The invention has for its object to provide an aqueous solution for structural separation capable of acting on carbon nanotubes (CNTs) having a specific structure thereby separating them with high accuracy, a separation and recovery method capable of allowing the aqueous solution to act on CNTs having a specific structure thereby separating and recovering them, and CNTs obtained by the separation and recovery method. According to the invention, it is possible to separate CNTs having a specific structure with high accuracy by solubilizing lithocholic acid or a lithocolic acid isomer that has high hydrophobicity and is insoluble in water by itself, and a carbon nanotube obtained by using an aqueous solution containing lithocholic acid or a lithocholic acid isomer, each solubilized, as an aqueous solution for structural separation of CNTs.

A method for making a carbon nanotube composite structure includes the following steps: dispersing a plurality of carbon nanotubes in water, to form a carbon nanotube dispersion; adding an aniline solution into the carbon nanotube dispersion, to form a mixed solution; adding an initiator into the mixed solution, to form a carbon nanotube composite structure preform; freeze-drying the carbon nanotube composite structure preform in a vacuum environment; and carbonizing the carbon nanotube composite structure preform in a protective gas after freeze-drying. The present application also relates to the carbon nanotube composite structure.

The present disclosure provides an apparatus capable of continuously producing carbon nanotubes having high crystallinity, a low residual catalyst content and a high aspect ratio. The apparatus for producing carbon nanotubes includes: a reaction unit configured to synthesize carbon nanotubes (CNTs), a supply unit configured to supply a carbon source to the reaction unit through a supply pipe; and a collection unit configured to collect carbon nanotubes discharged from the reaction unit, wherein the reaction unit may include a chemical vapor deposition reactor.

The present invention has an object to provide a carbon nanotube aggregate exhibiting excellent grip force in room temperature and high temperature environments. The present invention relates to a carbon nanotube aggregate comprising a plurality of carbon nanotubes aggregated in a sheet form, wherein a degree of orientation in a middle part is less than 84%, and a degree of orientation in at least one surface part is 15% or more.