Porous silica nanosheets in PIM-1 membranes for CO2 separation

PIM-1-based freestanding mixed matrix membranes (MMMs) and thin film nanocomposites (TFNs) were prepared by incorporating porous silica nanosheets (SN) exfoliated SN (E-SN) derived from natural vermiculite (Verm) in the PIM-1 polymer matrix. In addition, functionalized sulfonic acid amine groups (S-SN N-SN, respectively) also used as fillers for preparation of MMMs. The gas separation performance was evaluated using CO2/CH4 CO2/N2 (1:1, v:v) binary mixtures. Among membranes, fresh ones (i.e. tested right after preparation) containing 0.05 wt% E-SN outperformed neat PIM-1, surpassing 2008 Robeson upper bound. At same filler concentration, MMMs with acid-functionalized (S-SN) exhibited 40% higher CO2 permeability, 20% selectivity almost membranes. Moreover, 150 days aging, these capable maintaining up to 68% their initial permeability (compared 37% PIM-1). When TFN incorporation S-SN led 35% permeance five times 28 days.