Deformation of AUK Microporous Carbon Adsorbent Induced by Methane Adsorption

The dependence of the relative linear deformation of AUK microporous carbon adsorbent on pressure is studied upon the adsorption of methane in the pressure range of 1 Pa to 6 MPa at 177.65, 216.2, 243.3, 273.15, 313, 333, and 393 K. It is found that the curves of adsorption-induced deformation show similar behavior; except for in the initial pressure range (p < 0.2 MPa), the adsorption-induced deformation increases with pressure and drops as the temperature rises. At low temperatures, a shrinkage region is observed in the initial part of the deformation curves that narrows with a rise in temperature. At temperatures above 350 K, the initial shrinkage is absent and the adsorbent expands with an increase in methane pressure. In the pressure and temperature ranges under investigation, the contribution of deformation to the differential isosteric heat of adsorption of AUK carbon adsorbent does not exceed 2%. It is shown that, upon the adsorption of CO(2), N(2), Ar, and CH(4) at 273 K and pressures below 6 MPa, the maximum deformation of AUK adsorbent varies cymbately with variations in the Lennard-Jones (6-12) potential constants for the pair interaction of gas molecules.