Poly (ether-block amide) thin-film membranes containing functionalized MIL-101 MOFs for efficient separation of CO2/CH4

Y In this study, a post-synthesis modification method was used to graft tetraethylenepentamine (TEPA) on MIL-101 (Cr) metal organic framework (MOF). The post-modified amine grafted MIL-101(Cr) was incorporated into poly (ether-block amide) (Pebax (R) 1657) to fabricate thin-film nanocomposite (TFN) membrane. A series of single gas permeation experiments were carried out through the synthesized membranes to evaluate the effect of amine functional groups on the gas permeability and selectivity. BET, FT-IR, XRD, and FE-SEM results indicated that the amine groups were grafted on MIL-101(Cr) successfully. Moreover, the morphological studies of synthesized membranes demonstrated the formation of uniform and non-defected composite selective layer over the polyethersulfone sublayer. Gas permeation tests revealed that the best performance of TFN membranes obtained for sample containing 5 wt% TEPA-MIL-101 at 4 bar; in which the CO2 permeability increased by 63% (34.6 Barrer) as compared with Pebax neat membrane (21.8 Barrer). Meanwhile, an outstanding CO2/CH4 selectivity of 46.3 was achieved, which was 110% greater than the parent neat Pebax membrane (21.1). The results showed that TFN membranes have great potential in CO2 separation at low pressure.

Automated summary

In this study, tetraethylenepentamine (TEPA) was successfully grafted onto MIL-101 (Cr) metal organic framework (MOF) using a post-synthesis modification method. The thin-film nanocomposite (TFN) membrane incorporating amine grafted MIL-101(Cr) showed significantly improved CO2 permeability and selectivity compared to the neat Pebax membrane. The results demonstrate the great potential of TFN membranes in CO2 separation at low pressure.