Mechanism of Methane's Adsorption on Nanometer Active Carbon at Supercritical State

Isosteric heats and adsorption isotherms of methane on nanometer active carbon were measured at supercritical temperature (273–373 K) and pressure from 0 to 10 MPa. The measured data agreed well with Dubinin-Astakhov (DA) model at lower pressure but failed when pressure exceeded a special range. General Freundlich (GF) equation was used to modify the DA equation at high pressure and thus formed a combined bisection model GFDA. The adsorption mechanism of methane on nanometer active carbon was raised according to GFDA model and the heterogeneous energy distribution of the adsorbent was analyzed.