Effects of silica loading on the absorption of carbon dioxide by mixed matrix membranes

Abstract

Fumed silica nanoparticles, TS-530 were used with polyvinylidene fluoride (PVDF) in this work to produce mixed matrix membranes (MMM). Various nanoparticle loading were used to observe the effects of different nanoparticle loading on the characteristics, morphology and gas absorption performance of the resulting MMMs. 0.5 wt%, 1.0 wt%, 1.5 wt%, 3 wt%, 5 wt% and 10 wt% silica nanoparticles were added into the polymer dope solution before the membranes were cast in flat sheet configuration. Membrane contact angle tests showed an increase of the contact angle with silica loading, which is a desired characteristic in membrane gas absorption process. Energy dispersive X-ray (EDX) surface mapping of these MMMs indicated that the nanoparticles were quite well distributed in the polymer matrix despite its tendency to agglomerate. Permeability of carbon dioxide (CO2) in a gas mixture of CO2 and nitrogen (N2) for MMMs were better compared to the pure PVDF membrane, with 1 wt% silica loading having the best CO2 permeability. Selectivity, however, decreased with increasing nanoparticles loading, which may be the result of poor compatibility between the nanoparticles and the polymer matrix.