REMOVAL OF IRON FROM CARBON NANOTUBES AND RECYCLING OF METAL CATALYST Russian patent published in 2024 - IPC C01B32/17 B82Y40/00 B01J31/20 

FIELD: chemistry.

SUBSTANCE: present invention provides a method of purifying nanostructured material containing carbon nanotubes, metal impurities and amorphous carbon impurities. Invention involves a method involving the following steps: (a) obtaining a certain amount of crude carbon nanostructured material as a result of a chemical vapor deposition process with a floating catalyst, wherein the crude carbon nanostructured material is contaminated with metal catalyst particles and amorphous carbon structures; (b) oxidation of the crude carbon nanostructured material by exposure to carbon dioxide at an elevated temperature, where oxidation removes amorphous carbon structures to form carbon dioxide-treated nanostructured material and carbon monoxide; (c) subjecting the carbon dioxide treated nanostructured material to a gas stream containing at least carbon monoxide obtained in step (b); (d) increasing the temperature of the carbon dioxide-treated nanostructured material and the gas stream from 20 °C to 200 °C to form a purified carbon nanostructured material and a gaseous stream containing volatile metal compounds; and (e) removing the gaseous stream from the purified carbon nanostructured material. Invention also relates to purified carbon nanostructured material.

EFFECT: effective removal of impurities of amorphous carbon and metal catalyst at low or moderate temperatures and pressure without damage or destruction of carbon nanotubes, possibility of formation of sufficient amount of carbon monoxide required for the stage of formation of carbonyl in situ during the stage of oxidation, which reduces total carbon emission of this method and the need for separate raw material of carbon monoxide.

18 cl, 5 dwg