STRESSES AND STRAINS IN ADSORBENT-ADSORBATE SYSTEMS

From thermodynamic considerations a simple equation is derived which correlates length changes of a porous rigid adsorbent with its elastic and adsorptive properties. The equation contains a structure factor which is a constant characteristic of the adsorbent. Calculated and observed results agree reasonably well and suggest that, in the cases concerned, the assumptions underlying the derivation of the equation are valid. The underlying assumptions are: (a) both adsorbate and adsorbent can each exist separately in equilibrium with externally applied forces in states that are thermodynamically identical with their states in the adsorbate-adsorbent system, (b) adsorption isotherms represent paths of thermodynamic reversibility.