The Sorption Mechanism of Pure Gases in a Homogenous Polymer Membrane-a Modified Dual-Mode Sorption Model

Sorption Mechanism of pure gases in a homogenous polymer membrane was studied. Based on the concept of the dual-mode sorption model, gas sorption in a glassy polymer membrane can be interpretal as two concurrent processes: （a）an ordinary dissolution in the homogenous region and （b）a multi-layered molede adsorption in the microcavities. By idealizing the ordinary dissolution in a polymer membrane as that in solution, a modified dual-mode sorption model was derived for pure gases in glassy polymer membranes with the combination of BET equation. The derived model was verifried by the experimental data as reported in the literature. The result showed very consistent between the theoretical and thee xperimental. With the consideration of both the multi-layeds molecule adsorption and the effect of the dissolved concentration on solubility coefficient, i.e., the interaction between gas and polymer, the derived model is capable of describing the sorption of gases both in a glassy polymer membrane and in a rubber one which Henry’s law is not obeyed.