Characterization of Cabot non-graphitized carbon blacks with a defective surface model: Adsorption of argon and nitrogen

A grand canonical Monte Carlo simulation (GCMC) is used to study the adsorption of argon and nitrogen on non-graphitized carbon black. The surface is assumed to be finite in length and composed of three graphene layers, the top layer of which contains defects. The isotherm obtained for the non-graphitized carbon shows a smooth S-shaped type while that obtained for the perfect graphene layer shows a wavy type. The isosteric heat is also affected by the defect; its behaviour versus loading exhibits a decrease at the beginning and then slightly increases once the first layer has been formed. The decreasing behaviour of isosteric heat at low loadings is not observed in the case of graphitized carbon black. The simulated results are compared against the experimental data of argon and nitrogen at 77 and 87.3 K on the Cabot carbon black BP 280, 460 and 2000. It is found that the defected finite surface describes well the data of these blacks. For the case of BP 2000 we have found that besides the defects of the surface, this sample contains a small population of small micropores having a width of 8.2 Å and its specific pore volume of 0.08 cm 3/g.