Adsorption-Induced and Thermal Deformation of Microporous Carbon Adsorbent upon n-Octane Adsorption

Abstract

Relative linear adsorption-induced deformation of granules of AR-V microporous carbon adsorbent has been measured upon n-octane adsorption at pressures p of 1 Pa to 1.6 kPa and temperatures T = 273, 293, 313, 353, and 393 K. At p > 200 Pa, the adsorption-induced deformation is positive and grows with p throughout the considered temperature range. Under isobaric conditions, the adsorption-induced deformation and the slope of deformation isotherms increase as T decreases. At p < 200 Pa and T < 350 K, the adsorption-induced deformation is negative. The range of adsorbent contraction narrows with an increase in T, and, at T > 350 K, the adsorbent expands throughout the pressure range. Molecular dynamics simulation has been employed to study the structure of n-octane adsorption associates in model slit-like micropores having a width corresponding to the effective size of micropores in AR-V adsorbent calculated in terms of the theory of volume filling of micropores. The structure of the adsorption associates has been related to the characteristic features of the adsorption-induced deformation of AR-V adsorbent.