Surface heterogeneity analysis of MWCNT from methane adsorption isotherms for adsorbed natural gas storage

Adsorption equilibria of methane on multi-walled carbon nanotube (MWCNT) were measured. For comparison of the adsorption properties, two zeolites (DAY and HSZ-320) were chosen. The isotherm data were obtained using a static volumetric method at 303.15 K, 313.15 K, 323.15 K and at pressures up to 3 MPa. Experimental data of zeolites and carbon nanotube were correlated by the Sips isotherm and the hybrid Langmuir-Sips equations, respectively. Isosteric enthalpies of adsorption were calculated as a function of surface loading.