Combination of ordered mesoporous silica MCM-41 and layered titanosilicate JDF-L1 fillers for 6FDA-based copolyimide mixed matrix membranes

MCM-41 is an ordered mesoporous silica that can be prepared in a spherical shape (440 nm diameter), while JDF-L1 is a layered microporous titanosilicate with sheet-like growth habit (about 105 nm thickness) and a pore size of about 0.3 nm. JDF-L1 is a good material for H-2 selective transport and MCM-41 spheres may improve permeability for most gases. These fillers have been used to cast mixed matrix membranes (MMMs) with copolyimide 6FDA-4MPD/6FDA-DABA as a continuous polymer matrix. JDF-L1 sheets with a preferential horizontal orientation provide H2 selectivity while improving the dispersion of MCM-41 particles in the MMMs. This was evidenced by statistical analysis of 30 cross-section backscattering SEM images in each analyzed membrane. Regarding H-2/CH4 separation, MMMs containing 8 and 4 wt% of MCM-41 and JDF-L1, respectively, showed an optimum H-2/CH4 selectivity value of 32.0 (with 440 Barrer of H-2 permeability). Finally, this study demonstrates that MMM performance can be enhanced by combining highly selective inorganic sheets with highly permeable inorganic spheres