Tailor-made asymmetric PVDF hollow fibers for soluble gas removal

Abstract

Tailor-made polyvinylidene fluoride (PVDF) asymmetric hollow-fiber membranes and their membrane modules were employed for soluble gas removal, such as H2S from waste gas streams. This study focused on the techniques of fabricating and characterizing the PVDF asymmetric hollow-fiber membranes and their membrane modules for removal of H2S using an aqueous solution containing 10% NaOH. A laminar parabolic velocity profile was used to characterize the flow of the H2S gas mixture in the hollow-fiber lumen. Effects of operating conditions and the morphological structures of the membranes on the membrane's coefficient, k(AM), were examined both theoretically and experimentally. The capabilities of the hollow-fiber membranes developed for removal of H2S from waste gas streams were evaluated and compared with conventional symmetric hydrophobic hollow-fiber membranes, such as polypropylene. An analysis of H2S transfer across the more developed PVDF membranes reveals that the membrane's coefficient, k(AM), evaluated from its structure parameters, such as the effective surface porosity and mean radius, agreed well with the experimental data obtained from absorption experiments.