Phenomenological Kinetics of Real Gas-Adsorption-Systems: Isothermal Kinetics and Kinetics of Thermodesorption

Abstract

All adsorption systems which have to deal with technology and environment are systems which are not in equilibrium. They are only on their way to achieving a certain adsorption equilibrium. Therefore, knowledge of the time evolution of adsorption systems should be of fundamental importance. However, the overwhelming majority of the published papers report on experimental and theoretical studies of adsorption equilibria. This is probably why the theories of adsorption equilibria are at present much more advanced than the theories of time evolution of non-equilibrium adsorption systems. The theories of the kinetics of gas adsorption/ desorption on/from flat solid surfaces provide a very impressive illustration. On both the experimental and theoretical side, one finds a level far behind that characterizing current studies of adsorption equilibria. One can still observe controversies concerning the fundamentals of adsorption/desorption kinetics. The present review reports on the most recent achievements in the theoretical description of both isothermal adsorption kinetics and kinetics of thermodesorption, achieved by applying the Statistical Rate Theory.