SKIN RESISTANCE FOR ADSORBATE MASS TRANSFER INTO EXTRUDED ADSORBENT PELLETS.

Three samples of extruded mordenite pellets were tested for nitrogen adsorption from air. Pure gas and binary isotherms for nitrogen and oxygen were measured by volumetric and desorption techniques, respectively. All three samples exhibited identical equilibrium isotherms and are quantitatively described by single and mixed Langmuir models. The internal pore structure and other physical properties of the adsorbents were measured by mercury porosimetry and helium pycnometry techniques. It was postulated that the external 'skins' of the three samples were different. Scanning electron micrographs of the interiors, the external surfaces, and the edges of the cross sections of these pellets qualitatively confirmed the existence of a dense non-crystalline material at the external surface of the extruded pellets.