Abstract
Membrane permeation and separation characteristics of mixed gas/membrane systems are typically calculated from single-component transport parameters, namely, diffusion coefficients and solubility constants. As a operating condition, temperature has great impact on permeability and selectivity of membrane for various gases and therefore the membrane efficiency.In this work, transport of oxygen and nitrogen through Poly(ethylene-co-vinyl acetate) (EVA) membranes prepared from polymeric solutions of EVA in tetrahydrofuran (THF), was studied by permeation measurements (variable pressure method) in different temperatures. Permeabilities, diffusivities and solubilities were determined for EVA films containing 28% (w/w) VA. Then these transport properties together with ideal selectivity were compared in four temperatures. By analyzing the acquired experimental data, we found out that permeability and diffusivity both increase with increasing temperature and also gas solubility increases slightly with temperature. Meanwhile we observed that temperature dependence of these transport properties obeys an Arrhenius-type relation. In the end, we calculated the activation energies of gas permeation (Ep) and diffusion (Ed) processes and the heat of gas solution (ΔHs).
