Gas sorption and permeation in mixed matrix membranes based on glassy polymers and silica nanoparticles

The improvement of the separation performance of polymeric membranes for gas separations has been pursued by the addition of specific fillers, which produced diverse and even unexpected behaviors, hard to rationalize and to predict, both quantitatively and qualitatively. In particular, the addition of fumed silica nanoparticles in glassy polymeric membranes has shown unusual properties that apparently lead to the indication that only a specific experimental analysis could provide the information required for the permeability and separation of the gases of interest.We review transport properties, solubility and permeability in mixed matrix membranes obtained by loading fumed silica nanoparticles in different glassy polymers, interesting for membrane separations, and revise the main modeling procedure suitable to calculate and predict the relevant transport properties in such mixed matrix membranes.

► Gas transport in mixed matrix membranes is reviewed.
► Effects of fumed silica nanofillers are presented.
► A model rationalization allows calculation of solubility, diffusivity and permeability.
► Expected gas selectivity in gas separations is also obtained.