Long-term study of CO2 absorption by PVDF/ZSM-5 hollow fiber mixed matrix membrane in gas-liquid contacting process

Abstract

In order to fabricate hollow fiber mixed matrix membrane (HFMMM) for long-term CO2 absorption process, ZSM-5 (Zeolite Socony Mobil–5) zeolite was modified using hexadecyltrichlorosilane for increasing hydrophobicity and then added to the polyvinylidene fluoride (PVDF) spinning dope. The in-house made HFMMMs were characterized in terms of gas permeance, overall porosity, average pore size, effective surface porosity, surface roughness, mechanical stability, and wetting resistance. The morphology of the HFMMMs was studied using SEM. The cross-sectional SEM images indicated that the membrane structure has changed from sponge-like to finger-like by ZSM-5 loading. The surface roughness increased by increasing ZSM-5 concentration in the spinning dope. The HFMMM spun from the spinning dope with 0.5 wt % of ZSM-5 zeolite showed that the CO2 absorption flux decreased 18.9% in the initial 115 h of the operation and then the absorption flux remained constant until the end of the operation. For plain PVDF HFM the absorption flux decreased 36% from the initial value in the first 15 h of the experiment. Thus it could be concluded that the long term stability of HFM was improved by the incorporation of ZSM-5.