The permeation of CO 2 and N 2 gases through asymmetric polyetherimide membrane

Abstract

The asymmetric hollow fiber membranes were prepared by the wet spinning of polyetheimide dope solution and the effect of hollow fiber structures on the permeation characteristics of carbon dioxide and nitrogen gases through these membrane were investigated. As the concentration of the γ-butyrolactone (GBL) in dope solution, acting as a swelling agent was increased, the structure of hollow fiber was changed from the finger to sponge type. The permeabilities of gases (CO 2, N 2) through these membrane were measured over the wide range of pressure under different temperature. The effect of water vapor on the permeabilities of gases was also investigated. The measured permeabilities showed the different characteristics depending on the structure of membranes. This experimental results were explained by the combination of gas phase flow, solution - diffusion flow mode and surface condensed flow. It was found that the flow through the pores were dominant over the polymers matrix. Blocking effect by water vapor in the pores of skin layer greatly improved the ideal separtion factor of carbon dioxide/nitrogen.