Preparation of carbon/carbon nanotubes doped with Co/N and their dye adsorption performance

In order to solve the problem of low specific surface areas and pore volumes, low nitrogen contents and wide pore size distributions of ZIFs based carbon materials at high temperatures, Micron-ZIF-67 was used as template, and PDA and MA were introduced as carbon and nitrogen precursors to improve nitrogen doping amount and regulate pore structure. Co/N-HCPC/CNTs were prepared by one-step carbonization at 800 ℃under the atmosphere of reducing gas and inert gas using the self-catalysis performance of Co in ZIF-67. The results show that the specific surface area, pore volume and the N-doped amount of Co/N-HCPC/CNTs can reach 723.2 m2∙g-1, 1.873 cm3∙g-1 and 4.06%, respectively. The pore size was between 1-30 nm with the maximum distribution at 3.8 nm, and the contribution of mesoporous to the specific surface area and pore volume was 89.7% and 98.39%. There are many nitrogen-containing and oxygen-containing functional groups on the surface of Co/N-HCPC/CNTs. C and N atoms formed coordination bonds with Co, which make the materials with more adsorption active sites. Co nanoparticles were wrapped by carbon nitrogen layer or encapsulated in carbon nanotubes, which made the material had stable magnetism and easy to realize solid-liquid separation. The highest adsorption capacity of Co/N-HCPC/CNTs for CR an MG were 361.7 mg∙g-1 and 1 332.6 mg∙g-1, respectively. The adsorption process was in accordance with the pseudo-second-order kinetic model and Freundlich isotherm adsorption model. © 2022, Editorial Board of "Journal of Chemical Engineering of Chinese Universities". All right reserved.